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1

Magnitogorsk Armor Plate.  

National Technical Information Service (NTIS)

This is a sketch of how the metallurgists at the Magnitogorsk (Magnitka) steel factory in the Soviet Union fulfilled the Soviet Union's need for armor plate during World War II. Since no mills for rolling armor plate existed in Magnitka before the war, en...

Y. Petrov

1968-01-01

2

Vacuum degassing of chromium-nickel-molybdenum steel at the Magnitogorsk Metallurgical Combine  

Microsoft Academic Search

The Magnitogorsk Metallurgical Combine has conducted a study of the effect of technological factors on the hydrogen content\\u000a of chromium-nickel-molybdenum steel after vacuum degassing. It was established that the most important factor is the hydrogen\\u000a content of the steel before the degassing operation. The study also determined the effects of the circulation coefficient,\\u000a the duration of the degassing operation, and

B. A. Sarychev; O. A. Nikolaev; A. F. Sarychev; D. I. Chigasov

2006-01-01

3

Preliminary fission-track results from the southern Urals — Sterlitamak to Magnitogorsk  

Microsoft Academic Search

Results are reported from a pilot fission-track study of a west-east traverse across the southern Urals from Sterlitamak through to the Dzhabyk granite, east of Magnitogorsk, which was undertaken in order to study the low-temperature (?300°C) thermotectonic post-Uralian history of the mountain belt. The transect crosses the major tectonic units including the Main Uralian Fault, the suture zone which separates

Diane Seward; Andres Pérez-Estaún; Victor Puchkov

1997-01-01

4

A Linear Programming Model of Integrated Iron and Steel Production  

Microsoft Academic Search

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

Tibor Fabian

1958-01-01

5

Updating the Circulating Vacuum Degassing Technology at the Magnitogorsk Iron and Steel Works Joint-Stock Co  

Microsoft Academic Search

Updating of a unit for outside-the-furnace vacuum degassing intended for the preparation of a low-carbon (= 0.004% C) IF-steel is described. The updating involved replacement of the electric heater for the work space with a gas-oxygen burner. Changes in the refractory lining wear rate associated with this replacement are discussed. Routes towards further improvement of the vacuum degassing technology are

Yu. A. Bodyaev; E. V. Burmistrova; V. G. Ovsyannikov; V. I. Frolov; S. A. Samoilin; I. M. Shatokhin

2004-01-01

6

Continuous X-ray fluorescence analysis of iron ore mixtures in the production of agglomerate  

Microsoft Academic Search

A system is developed for the continuous control of the chemical composition of iron ore mixtures (IOMs) by X-ray fluorescence analysis (XRF) directly on the conveyor belt. The system was found to be efficient under the conditions of mining and smelting production\\u000a at the Magnitogorsk Metallurgical Combine. The proposed XRF method does not require sampling; provides the required accuracy;\\u000a and

N. V. Alov; A. I. Volkov; A. I. Usherov; E. N. Ishmets’ev; E. V. Usherova

2010-01-01

7

A novel streptococcal integrative conjugative element involved in iron acquisition  

PubMed Central

In this study, we determined the function of a novel non-ribosomal peptide synthetase (NRPS) system carried by a streptococcal integrative conjugative element (ICE), ICESe2. The NRPS shares similarity with the yersiniabactin system found in the high-pathogenicity island of Yersinia sp. and is the first of its kind to be identified in streptococci. We named the NRPS product ‘equibactin’ and genes of this locus eqbA–N. ICESe2, although absolutely conserved in Streptococcus equi, the causative agent of equine strangles, was absent from all strains of the closely related opportunistic pathogen Streptococcus zooepidemicus. Binding of EqbA, a DtxR-like regulator, to the eqbB promoter was increased in the presence of cations. Deletion of eqbA resulted in a small-colony phenotype. Further deletion of the irp2 homologue eqbE, or the genes eqbH, eqbI and eqbJ encoding a putative ABC transporter, or addition of the iron chelator nitrilotriacetate, reversed this phenotype, implicating iron toxicity. Quantification of 55Fe accumulation and sensitivity to streptonigrin suggested that equibactin is secreted by S. equi and that the eqbH, eqbI and eqbJ genes are required for its associated iron import. In agreement with a structure-based model of equibactin synthesis, supplementation of chemically defined media with salicylate was required for equibactin production.

Heather, Zoe; Holden, Matthew T G; Steward, Karen F; Parkhill, Julian; Song, Lijiang; Challis, Gregory L; Robinson, Carl; Davis-Poynter, Nicholas; Waller, Andrew S

2008-01-01

8

[Heme metabolism as an integral part of iron homeostasis].  

PubMed

Heme, a ferrous iron protoporphyrin IX complex, is employed as a prosthetic group in a number of diverse heme proteins that participate in important cellular and systemic physiological processes. Provision of an adequate amount of iron for heme biosynthesis is one of the elemental hallmarks of intracellular iron homeostasis. In the cell the bioavailability of iron for the two main iron biological pathways--heme synthesis and the biogenesis of iron-sulfur clusters ([Fe-S])--is mainly regulated by the IRP/IRE posttranscriptional system. The biogenesis of [Fe-S] centers is crucial for heme synthesis because these co-factors determine the activity of IRP1 and that of ferrochelatase, an enzyme responsible for the insertion of an iron into protoporphyrin IX to produce heme. On the other hand, delivery of iron for heme and hemoglobin synthesis in erythroblasts, precursors of erythrocytes in bone marrow, is an indispensable element of body iron homeostasis. This process relies on the recovery of iron from senescent red blood cells through the enzymatic degradation of heme molecules and recycling of iron to the circulation. Molecular coordination of these processes involves the activity of heme oxygenase 1, IRP1 and IRP2 as well as the functioning of the hepcidin-ferroportin regulatory axis. Recent studies show in mammals the existence of an expanded system of proteins involved in the transport of intact heme molecules at the cellular and systemic levels. The biological role of this system is of particular importance when the concentration of free heme reaches a toxic level in the body (intravascular hemolysis) as well as locally in cells having intensive heme metabolism such as erythroblasts and macrophages. PMID:24864106

Lipi?ski, Pawe?; Starzy?ski, Rafa? R; Sty?, Agnieszka; Gajowiak, Anna; Staro?, Robert

2014-01-01

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

Iron  

Microsoft Academic Search

Iron poisoning causes its metabolic effects in proportion to the concentrations of free iron. Toxicity is therefore related to dose ingested. The amount of iron in different salts varies, and iron concentrations may rise and fall, making plasma concentrations difficult to interpret in acute poisoning. Clinical features include severe gastrointestinal irritation, cardiovascular collapse and direct organ damage to liver and

D. Nicholas Bateman

2007-01-01

11

AP-42 ADDITIONS AND REVISIONS - INTEGRATED IRON AND STEEL INDUSTRY - STEEL MINI MILLS  

EPA Science Inventory

This project develops emission factors, etc., for the integrated iron and steel industry which are incorporated into AP-42. AP-42 is a massive collection of information concerning processes which generate air emissions and presents emission factors and control effectiveness infor...

12

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

NASA Astrophysics Data System (ADS)

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.

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

2014-03-01

13

Assessing dust exposure in an integrated iron and steel manufacturing plant in South India.  

PubMed

A study to monitor and estimate respirable particulate matter (RPM), toxic trace metal concentrations in the work environment was carried out in different sections of an integrated steel manufacturing industry. The average RPM concentration observed varied according to the section blast furnace was 2.41 mg/m;{3}; energy optimization furnace, 1.87 mg/m;{3}; sintering plant, 0.98 mg/m;{3}; continuous casting machine, 1.93 mg/m;{3}. The average trace metal concentration estimated from the RPM samples like iron, manganese, lead and chromium did not exceed ACGIH prescribed levels. PMID:18413935

Ravichandran, B; Krishnamurthy, V; Ravibabu, K; Raghavan, S; Rajan, B K; Rajmohan, H R

2008-01-01

14

Chemical profile identification of fugitive and confined particle emissions from an integrated iron and steelmaking plant.  

PubMed

The aim of this study is to obtain the characteristic inorganic chemical profile of important particle sources identified in the integrated iron and steel process: sintering, blast furnace, steelmaking and desulfurization slag processing. A complete chemical and physical characterization program was developed: particle size distribution, chemical analysis, XRD, SEM-EDX and TGA/DTA. The sample collected from the sinter stack showed high levels of K and Cl(-), followed by Fe, NH4(+), Ca, Na and Pb. The profile of the dust samples taken from the sinter cake discharge zone was quite different, showing higher amounts of Fe, Ca and Al, and lower amounts of K, Cl(-), Na and Pb. Dust samples collected from the blast furnace (BF) and steelmaking cast house may be distinguished from each other based on the higher levels of Fe (hematite and magnetite) and lower levels of Ca, Zn and C (graphite) found in BF dust. High levels of Ca and Fe were found in samples taken from the desulfurization slag processing area. Such information can be useful for source apportionment studies at receptor sites that could be influenced by iron and steelmaking plant emissions. PMID:23454464

Hleis, Dany; Fernández-Olmo, Ignacio; Ledoux, Frédéric; Kfoury, Adib; Courcot, Lucie; Desmonts, Thérèse; Courcot, Dominique

2013-04-15

15

Conceptual design and modelling of the Steam-Iron process and fuel cell integrated system  

Microsoft Academic Search

The Steam-Iron process, based on the redox reaction of iron oxides (Fe3O4+4H2?3Fe+4H2O), is an interesting alternative to other methods of storing and generating pure hydrogen. In order to evaluate the ability of the Steam-Iron process to supply hydrogen to a solid oxide fuel cell (SOFC), a mathematical model for the oxidation process in a fixed bed reactor has been developed

E. Lorente; Q. Cai; J. A. Peña; J. Herguido; N. P. Brandon

2009-01-01

16

Synthesis of iron-based chemical looping sorbents integrated with pH swing carbon mineral sequestration.  

PubMed

The previously developed pH swing carbon mineral sequestration immobilizes the gaseous CO2 into a thermodynamically stable solid, MgCO3, using Mg-bearing minerals such as serpentine. This mineral carbonation technology is particularly promising since it generates value-added solid products: high surface area silica, iron oxide, and magnesium carbonate, while providing a safe and permanent storage option for CO2. By carefully controlling the pH of the system, these solids products can be produced with high purity. This study focuses on the synthesis of iron oxide particles as a chemical looping sorbent in order to achieve the integration between carbon capture and storage technologies. Since the solubility of Fe in aqueous phase is relatively low at neutral pH, the effect of the weak acid and chelating agents on the extraction of Fe from serpentine was investigated. The synthesized iron-based chemical looping sorbent was found to be as effective as commercially available iron oxide nanoparticles at converting syngas into high purity H2, while producing a sequestration-ready CO2 stream. PMID:19908801

Kim, Hyung Ray; Lee, Dong Hyun; Fan, Liang-Shih; Park, Ah-Hyung Alissa

2009-12-01

17

Integrating microarray analysis and the soybean genome to understand the soybeans iron deficiency response  

PubMed Central

Background Soybeans grown in the upper Midwestern United States often suffer from iron deficiency chlorosis, which results in yield loss at the end of the season. To better understand the effect of iron availability on soybean yield, we identified genes in two near isogenic lines with changes in expression patterns when plants were grown in iron sufficient and iron deficient conditions. Results Transcriptional profiles of soybean (Glycine max, L. Merr) near isogenic lines Clark (PI548553, iron efficient) and IsoClark (PI547430, iron inefficient) grown under Fe-sufficient and Fe-limited conditions were analyzed and compared using the Affymetrix® GeneChip® Soybean Genome Array. There were 835 candidate genes in the Clark (PI548553) genotype and 200 candidate genes in the IsoClark (PI547430) genotype putatively involved in soybean's iron stress response. Of these candidate genes, fifty-eight genes in the Clark genotype were identified with a genetic location within known iron efficiency QTL and 21 in the IsoClark genotype. The arrays also identified 170 single feature polymorphisms (SFPs) specific to either Clark or IsoClark. A sliding window analysis of the microarray data and the 7X genome assembly coupled with an iterative model of the data showed the candidate genes are clustered in the genome. An analysis of 5' untranslated regions in the promoter of candidate genes identified 11 conserved motifs in 248 differentially expressed genes, all from the Clark genotype, representing 129 clusters identified earlier, confirming the cluster analysis results. Conclusion These analyses have identified the first genes with expression patterns that are affected by iron stress and are located within QTL specific to iron deficiency stress. The genetic location and promoter motif analysis results support the hypothesis that the differentially expressed genes are co-regulated. The combined results of all analyses lead us to postulate iron inefficiency in soybean is a result of a mutation in a transcription factor(s), which controls the expression of genes required in inducing an iron stress response.

2009-01-01

18

Monolithic integration of chalcogenide glass/iron garnet waveguides and resonators for on-chip nonreciprocal photonic devices  

NASA Astrophysics Data System (ADS)

We report monolithic integration of chalcogenide glass(ChG)/iron garnet waveguides and racetrack resonators on silicon for on-chip nonreciprocal photonic devices applications. Using a two step growth strategy, we successfully integrated phase pure Bi0.8Y2.2Fe5O12 (Bi0.8YIG), Bi1.8Y1.2Fe5O12 (Bi1.8YIG) and Ce1Y2Fe5O12 (CeYIG) polycrystalline thin films on silicon with low fabrication thermal budgets. Strip-loaded ChG/Iron garnet waveguides and racetrack resonators were fabricated by thermal evaporation and lift off. The waveguide loss was systematically characterized by cutback and paperclip methods. For the first time, the optical transmission loss of polycrystalline Bi or Ce doped garnets were evaluated at communication wavelengths in waveguides. Polycrystalline CeYIG films show a saturation Faraday rotation of -830deg/cm and transmission loss of ~40dB/cm at 1550nm, which is promising for on-chip nonreciprocal photonic device applications. Such waveguide structures were successfully incorporated in GeS2/Bi0.8YIG racetrack resonators which show well defined resonance spectrum at near infrared wavelength. The nonreciprocal phase shift (NRPS) and device figure of merit of the ChG/Garnet waveguides were simulated by numerical methods. Possible improvements and applications of such devices for integrated optical isolator applications are analyzed and discussed.

Bi, Lei; Hu, Juejun; Dionne, Gerald F.; Kimerling, Lionel; Ross, C. A.

2011-02-01

19

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...

20

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

PubMed Central

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.

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

21

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

SciTech Connect

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.}

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

22

Integrating yttrium iron garnet onto nongarnet substrates with faster deposition rates and high reliability  

SciTech Connect

Magneto-optical garnets (Y{sub 3}Fe{sub 5}O{sub 12} or YIG) were grown monolithically by a novel reactive radio-frequency sputtering method that used a partial pressure differential to increase sputtering rates. MgO and quartz substrates were used as they are good buffer layers and optical claddings for integration. A wide single-phase field for annealed YIG was found (26.9-43.2 at % Y), and the magnetic properties were measured. The films had refractive indices of 2.1 and out-of-plane Faraday rotations up to 0.2 deg. /{mu}m at 633 nm. The dielectric matrix was used to calculate the difference in the propagation constants of forward and backward traveling light ({delta}{beta}=1.999x10{sup -5})

Sung, S.-Y.; Qi Xiaoyuan; Stadler, Bethanie J.H. [Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, Minnesota 55455 (United States)

2005-09-19

23

New evidence on iron, copper accumulation and zinc depletion and its correlation with DNA integrity in aging human brain regions  

PubMed Central

Deoxyribonucleic acid (DNA) conformation and stability play an important role in brain function. Earlier studies reported alterations in DNA integrity in the brain regions of neurological disorders like Parkinson’s and Alzheimer’s diseases. However, there are only limited studies on DNA stability in an aging brain and the factors responsible for genomic instability are still not clear. In this study, we assess the levels of Copper (Cu), Iron (Fe) and Zinc (Zn) in three age groups (Group I: below 40 years), Group II: between 41-60 years) and Group III: above 61 years) in hippocampus and frontal cortex regions of normal brains. The number of samples in each group was eight. Genomic DNA was isolated and DNA integrity was studied by nick translation studies and presented as single and double strand breaks. The number of single strand breaks correspondingly increased with aging compared to double strand breaks. The strand breaks were more in frontal cortex compared to hippocampus. We observed that the levels of Cu and Fe are significantly elevated while Zn is significantly depleted as one progresses from Group I to Group III, indicating changes with aging in frontal cortex and hippocampus. But the elevation of metals was more in frontal cortical region compared to hippocampal region. There was a clear correlation between Cu and Fe levels versus strand breaks in aging brain regions. This indicates that genomic instability is progressive with aging and this will alter the gene expressions. To our knowledge, this is a new comprehensive database to date, looking at the levels of redox metals and corresponding strand breaks in DNA in two brain regions of the aging brain. The biological significance of these findings with relevance to mental health will be discussed.

Vasudevaraju, P.; Bharathi; T, Jyothsna; Shamasundar, N. M.; Subba Rao, K.; Balaraj, B. M.; KSJ, Rao; T.S, Sathyanarayana Rao

2010-01-01

24

Utilization of Industrial Waste Heat, Citing an Integrated Iron and Steel Works as an Example to Save Primary Energy and to Reduce the Burden on the Environment, Volume 2.  

National Technical Information Service (NTIS)

The potential of waste energy utilization in an integrated iron and steel works were investigated in technical and economic terms. The utilization of wste heat to substitute primary energy is an essential factor to complement the savings of primary energy...

H. G. Poettken H. Strohschein

1982-01-01

25

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

PubMed Central

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.

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

2014-01-01

26

Magneto-optical properties of cerium substituted yttrium iron garnet films with reduced thermal budget for monolithic photonic integrated circuits.  

PubMed

Thin films of polycrystalline cerium substituted yttrium iron garnet (CeYIG) were grown on an yttrium iron garnet (YIG) seed layer on Si and Si-on-insulator substrates by pulsed laser deposition, and their optical and magneto-optical properties in the near-IR region were measured. A YIG seed layer of ~30 nm thick processed by rapid thermal anneal at 800°C provided a virtual substrate to promote crystallization of the CeYIG. The effect of the thermal budget of the YIG/CeYIG growth process on the film structure, magnetic and magnetooptical properties was determined. PMID:23263087

Goto, Taichi; Onba?l?, Mehmet C; Ross, C A

2012-12-17

27

The Iron Transport Protein NRAMP2 Is an Integral Membrane Glycoprotein That Colocalizes with Transferrin in Recycling Endosomes  

Microsoft Academic Search

Summary The natural resistance associated macrophage protein ( Nramp ) gene family is composed of two members in mammals, Nramp1 and Nramp2. Nramp1 is expressed primarily in macrophages and mutations at this locus cause susceptibility to infectious diseases. Nramp2 has a much broader range of tissue expression and mutations at Nramp2 result in iron deficiency, indicating a role for Nramp2

Samantha Gruenheid; François Canonne-Hergaux; Susan Gauthier; David J. Hackam; Sergio Grinstein; Philippe Gros

28

Iron acquisition by teleost fish  

Microsoft Academic Search

Iron is a vital micronutrient for teleost fish, being an integral component of proteins involved in cellular respiration and oxygen transfer. However, in excess iron is toxic, and fish need to balance uptake to prevent deficiency vs. potential toxicity. This review assesses the current physiological and molecular knowledge of the mechanisms of iron acquisition in the teleost fish. It focuses

Nicolas Bury; Martin Grosell

2003-01-01

29

The MAP kinase MpkA controls cell wall integrity, oxidative stress response, gliotoxin production and iron adaptation in Aspergillus fumigatus.  

PubMed

The saprophytic fungus Aspergillus fumigatus is the most important air-borne fungal pathogen. The cell wall of A. fumigatus has been studied intensively as a potential target for development of effective antifungal agents. A major role in maintaining cell wall integrity is played by the mitogen-activated protein kinase (MAPK) MpkA. To gain a comprehensive insight into this central signal transduction pathway, we performed a transcriptome analysis of the ?mpkA mutant under standard and cell wall stress conditions. Besides genes involved in cell wall remodelling, protection against ROS and secondary metabolism such as gliotoxin, pyomelanin and pseurotin A, also genes involved in siderophore biosynthesis were regulated by MpkA. Consistently, northern and western blot analyses indicated that iron starvation triggers phosphorylation and thus activation of MpkA. Furthermore, localization studies indicated that MpkA accumulates in the nucleus under iron depletion. Hence, we report the first connection between a MAPK pathway and siderophore biosynthesis. The measurement of amino acid pools and of the pools of polyamines indicated that arginine was continuously converted into ornithine to fuel the siderophore pool in the ?mpkA mutant strain. Based on our data, we propose that MpkA fine-tunes the balance between stress response and energy consuming cellular processes. PMID:21883519

Jain, Radhika; Valiante, Vito; Remme, Nicole; Docimo, Teresa; Heinekamp, Thorsten; Hertweck, Christian; Gershenzon, Jonathan; Haas, Hubertus; Brakhage, Axel A

2011-10-01

30

Integrated self-assembly of the Mms6 magnetosome protein to form an iron-responsive structure.  

PubMed

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

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

2013-01-01

31

Fully quantum mechanical calculation of the diffusivity of hydrogen in iron using the tight-binding approximation and path integral theory  

NASA Astrophysics Data System (ADS)

We present calculations of free energy barriers and diffusivities as functions of temperature for the diffusion of hydrogen in ?-Fe. This is a fully quantum mechanical approach since the total energy landscape is computed using a self-consistent, transferable tight binding model for interstitial impurities in magnetic iron. Also the hydrogen nucleus is treated quantum mechanically and we compare here two approaches in the literature both based in the Feynman path integral formulation of statistical mechanics. We find that the quantum transition state theory which admits greater freedom for the proton to explore phase space gives result in better agreement with experiment than the alternative which is based on fixed centroid calculations of the free energy barrier. This will have an impact on future modeling and the simulation of hydrogen trapping and diffusion.

Katzarov, Ivaylo H.; Pashov, Dimitar L.; Paxton, Anthony T.

2013-08-01

32

Iron shielded MRI optimization  

Microsoft Academic Search

The design of the main current systems of an actively shielded and of an iron shielded MRI device for nuclear resonance imaging, is considered. The model for the analysis of the magnetic induction produced by the current system, is based on the combination of a Boundary Element technique and of the integration of two Fredholm integral equations of the first

C. A. Borghi; M. Fabbri

1998-01-01

33

Development of Bottom-up Representation of Industrial Energy Efficiency Technologies in Integrated Assessment Models for the Iron and Steel Sector  

SciTech Connect

Adoption of efficient end-use technologies is one of the key measures for reducing greenhouse gas (GHG) emissions. With the working of energy programs and policies on carbon regulation, how to effectively analyze and manage the costs associated with GHG reductions become extremely important for the industry and policy makers around the world. Energy-climate (EC) models are often used for analyzing the costs of reducing GHG emissions (e.g., carbon emission) for various emission-reduction measures, because an accurate estimation of these costs is critical for identifying and choosing optimal emission reduction measures, and for developing related policy options to accelerate market adoption and technology implementation. However, accuracies of assessing of GHG-emission reduction costs by taking into account the adoption of energy efficiency technologies will depend on how well these end-use technologies are represented in integrated assessment models (IAM) and other energy-climate models. In this report, we first conduct brief overview on different representations of end-use technologies (mitigation measures) in various energy-climate models, followed by problem statements, and a description of the basic concepts of quantifying the cost of conserved energy including integrating non-regrets options. A non-regrets option is defined as a GHG reduction option that is cost effective, without considering their additional benefits related to reducing GHG emissions. Based upon these, we develop information on costs of mitigation measures and technological change. These serve as the basis for collating the data on energy savings and costs for their future use in integrated assessment models. In addition to descriptions of the iron and steel making processes, and the mitigation measures identified in this study, the report includes tabulated databases on costs of measure implementation, energy savings, carbon-emission reduction, and lifetimes. The cost curve data on mitigation measures are available over time, which allows an estimation of technological change over a decade-long historical period. In particular, the report will describe new treatment of technological change in energy-climate modeling for this industry sector, i.e., assessing the changes in costs and energy-savings potentials via comparing 1994 and 2002 conservation supply curves. In this study, we compared the same set of mitigation measures for both 1994 and 2002 -- no additional mitigation measure for year 2002 was included due to unavailability of such data. Therefore, the estimated potentials in total energy savings and carbon reduction would most likely be more conservative for year 2002 in this study. Based upon the cost curves, the rate of change in the savings potential at a given cost can be evaluated and be used to estimate future rates of change that can be the input for energy-climate models. Through characterizing energy-efficiency technology costs and improvement potentials, we have developed and presented energy cost curves for energy efficiency measures applicable to the U.S. iron and steel industry for the years 1994 and 2002. The cost curves can change significantly under various scenarios: the baseline year, discount rate, energy intensity, production, industry structure (e.g., integrated versus secondary steel making and number of plants), efficiency (or mitigation) measures, share of iron and steel production to which the individual measures can be applied, and inclusion of other non-energy benefits. Inclusion of other non-energy benefits from implementing mitigation measures can reduce the costs of conserved energy significantly. In addition, costs of conserved energy (CCE) for individual mitigation measures increase with the increases in discount rates, resulting in a general increase in total cost of mitigation measures for implementation and operation with a higher discount rate. In 1994, integrated steel mills in the U.S. produced 55.

Xu, T.T.; Sathaye, J.; Galitsky, C.

2010-09-30

34

Integration  

ERIC Educational Resources Information Center

Integrated learning is an exciting adventure for both teachers and students. It is not uncommon to observe the integration of academic subjects such as math, science, and language arts. However, educators need to recognize that movement experiences in physical education also can be linked to academic curricula and, may even lead the…

Kalyn, Brenda

2006-01-01

35

Integration of nanosized zero-valent iron particles addition with UV/H2O2 process for purification of azo dye Acid Black 24 solution.  

PubMed

The challenging national effluent standards for color and organic concentration enforce the industrial concern most the techniques providing fast and efficient solution for the strenuous dye wastewater treatment before outflow. The best remediation technique pursuit is urgently demand for the industrial, government, academia and community. In this study, a di-azo dye, C.I. Acid Black 24, synthesized wastewater was successfully removed synchronously its total color and total organic carbon (TOC) using an integrated innovation technology by coupling the zero-valent iron (ZVI) nanoparticles with UV/H(2)O(2) oxidation process. The nanosized ZVI (NZVI) primarily reduced color successfully following coupling UV/H(2)O(2) oxidation process for the residual organic mineralization resulting reduction with oxidation process (Re-Ox) for total color removal and organic mineralization. From the experimental data, the Re-Ox process consumed shorter time than UV/H(2)O(2) oxidation process alone to obtain total color removal of dye wastewater. Moreover, the residual TOC of dye wastewater after NZVI reduction from 45 to 100% was effectively mineralized by UV/H(2)O(2) process. By using proposed processes integration with NZVI dosage of 0.3348 g l(-1) and hydrogen peroxide concentration of 23.2 mM, in only 10 min the AB24 color was complete eliminated and in 90 min the TOC was 93.9% removed. Thus, the coupling Re-Ox process was developed to provide a superior solution for dye wastewater treatment. PMID:19250743

Shu, Hung-Yee; Chang, Ming-Chin; Chang, Chi-Chen

2009-08-15

36

Iron Ore.  

National Technical Information Service (NTIS)

Iron ore is an important mineral commodity because it is the primary source of iron, the metal most widely used by man. World production of iron ore in 1977 was estimated at 840 million tons, and an estimated 350 million tons was shipped in international ...

F. L. Klinger

1978-01-01

37

Human CIA2A-FAM96A and CIA2B-FAM96B integrate iron homeostasis and maturation of different subsets of cytosolic-nuclear iron-sulfur proteins.  

PubMed

Numerous cytosolic and nuclear proteins involved in metabolism, DNA maintenance, protein translation, or iron homeostasis depend on iron-sulfur (Fe/S) cofactors, yet their assembly is poorly defined. Here, we identify and characterize human CIA2A (FAM96A), CIA2B (FAM96B), and CIA1 (CIAO1) as components of the cytosolic Fe/S protein assembly (CIA) machinery. CIA1 associates with either CIA2A or CIA2B and the CIA-targeting factor MMS19. The CIA2B-CIA1-MMS19 complex binds to and facilitates assembly of most cytosolic-nuclear Fe/S proteins. In contrast, CIA2A specifically matures iron regulatory protein 1 (IRP1), which is critical for cellular iron homeostasis. Surprisingly, a second layer of iron regulation involves the stabilization of IRP2 by CIA2A binding or upon depletion of CIA2B or MMS19, even though IRP2 lacks an Fe/S cluster. In summary, CIA2B-CIA1-MMS19 and CIA2A-CIA1 assist different branches of Fe/S protein assembly and intimately link this process to cellular iron regulation via IRP1 Fe/S cluster maturation and IRP2 stabilization. PMID:23891004

Stehling, Oliver; Mascarenhas, Judita; Vashisht, Ajay A; Sheftel, Alex D; Niggemeyer, Brigitte; Rösser, Ralf; Pierik, Antonio J; Wohlschlegel, James A; Lill, Roland

2013-08-01

38

Integration  

NSDL National Science Digital Library

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.

Liao, David

39

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

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.

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

40

[Iron deficiency in domestic animals].  

PubMed

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

Agergaard, N; Rotenberg, S; Boisen, S

1984-01-01

41

Iron refractory iron deficiency anemia  

PubMed Central

Iron refractory iron deficiency anemia is a hereditary recessive anemia due to a defect in the TMPRSS6 gene encoding Matriptase-2. This protein is a transmembrane serine protease that plays an essential role in down-regulating hepcidin, the key regulator of iron homeostasis. Hallmarks of this disease are microcytic hypochromic anemia, low transferrin saturation and normal/high serum hepcidin values. The anemia appears in the post-natal period, although in some cases it is only diagnosed in adulthood. The disease is refractory to oral iron treatment but shows a slow response to intravenous iron injections and partial correction of the anemia. To date, 40 different Matriptase-2 mutations have been reported, affecting all the functional domains of the large ectodomain of the protein. In vitro experiments on transfected cells suggest that Matriptase-2 cleaves Hemojuvelin, a major regulator of hepcidin expression and that this function is altered in this genetic form of anemia. In contrast to the low/undetectable hepcidin levels observed in acquired iron deficiency, in patients with Matriptase-2 deficiency, serum hepcidin is inappropriately high for the low iron status and accounts for the absent/delayed response to oral iron treatment. A challenge for the clinicians and pediatricians is the recognition of the disorder among iron deficiency and other microcytic anemias commonly found in pediatric patients. The current treatment of iron refractory iron deficiency anemia is based on parenteral iron administration; in the future, manipulation of the hepcidin pathway with the aim of suppressing it might become an alternative therapeutic approach.

De Falco, Luigia; Sanchez, Mayka; Silvestri, Laura; Kannengiesser, Caroline; Muckenthaler, Martina U.; Iolascon, Achille; Gouya, Laurent; Camaschella, Clara; Beaumont, Carole

2013-01-01

42

Iron Toxicity and Chelation Therapy  

Microsoft Academic Search

Iron is an essential mineral for normal cellular physiology, but an excess can result in cell injury. Iron in low-molecular-weight\\u000a forms may play a catalytic role in the initiation of free radical reactions. The resulting oxyradicals have the potential\\u000a to damage cellular lipids, nucleic acids, proteins, and carbohydrates; the result is wide-ranging impairment in cellular function\\u000a and integrity. The rate

Robert S. Britton; Katherine L. Leicester; Bruce R. Bacon

2002-01-01

43

Serum iron  

MedlinePLUS

Higher-than-normal levels may mean: Hemochromatosis Hemolysis Hemolytic anemias Hemosiderosis Liver tissue death (hepatic necrosis ) Hepatitis Vitamin B-12 deficiency, vitamin B-6 deficiency Iron poisoning Many blood transfusions Lower- ...

44

Iron Test  

MedlinePLUS

... and Kowdley, K. (2012). Review Article: The Iron Overload Syndromes. Medscape Reference from Aliment Pharmacol Ther . V35 (8):876-893. [On-line information]. Available online at http://www.medscape.com/viewarticle/ ...

45

Iron contamination in silicon technology  

NASA Astrophysics Data System (ADS)

This article continues the review of fundamental physical properties of iron and its complexes in silicon (Appl. Phys. A 69, 13 (1999)), and is focused on ongoing applied research of iron in silicon technology. The first section of this article presents an analysis of the effect of iron on devices, including integrated circuits, power devices, and solar cells. Then, sources of unintentional iron contamination and reaction paths of iron during device manufacturing are discussed. Experimental techniques to measure trace contamination levels of iron in silicon, such as minority carrier lifetime techniques (SPV, ?-PCD, and ELYMAT), deep-level transient spectroscopy (DLTS), total X-ray fluorescence (TXRF) and vapor-phase decomposition TXRF (VPD-TXRF), atomic absorption spectroscopy (AAS), mass spectrometry and its modifications (SIMS, SNMS, ICP-MS), and neutron activation analysis (NAA) are reviewed in the second section of the article. Prospective analytical tools, such as heavy-ion backscattering spectroscopy (HIBS) and synchrotron-based X-ray microprobe techniques (XPS, XANES, XRF) are briefly discussed. The third section includes a discussion of the present achievements and challenges of the electrochemistry and physics of cleaning of silicon wafers, with an emphasis on removal of iron contamination from the wafers. Finally, the techniques for gettering of iron are presented.

Istratov, A. A.; Hieslmair, H.; Weber, E. R.

46

Iron Homeostasis and the Inflammatory Response  

PubMed Central

Iron and its homeostasis are intimately tied to the inflammatory response. The adaptation to iron deficiency, which confers resistance to infection and improves the inflammatory condition, underlies what is probably the most obvious link: the anemia of inflammation or chronic disease. A large number of stimulatory inputs must be integrated to tightly control iron homeostasis during the inflammatory response. In order to understand the pathways of iron trafficking and how they are regulated, this chapter will present a brief overview of iron homeostasis. A major focus will be on the regulation of the peptide hormone hepcidin during the inflammatory response and how its function contributes to the process of iron withdrawal. The review will also summarize new and emerging information about other iron metabolic regulators and effectors that contribute to the inflammatory response. Potential benefits of treatment to ameliorate the hypoferremic condition promoted by inflammation will also be considered.

Wessling-Resnick, Marianne

2011-01-01

47

Iron control in zinc pressure leach processes  

NASA Astrophysics Data System (ADS)

The occurrence of zinc in sulfide ore deposits is generally accompanied by various iron minerals. Hence, even the most efficient concentrators generally produce a zinc concentrate with significant iron content. The efficient recovery of zinc metal from zinc concentrates requires the rejection of iron residue in a form that minimizes the zinc entrainment. Careful control of the iron precipitation step is important, so that the iron residue produced is amenable to efficient liquid-solid separation in order to obtain high zinc recoveries. In hydrometallurgical zinc processes, the coprecipitation of minor impurities along with iron precipitation is also important in producing zinc-sulfate solution from which high-purity zinc cathode can be electrowon. The integration of Dynatec’s zinc pressure leach process with existing roast-leach-electrowin plants employing various methods of iron rejection is briefly described in this article, along with the application of two-stage pressure leaching in stand-alone processes.

Buban, K. R.; Collins, M. J.; Masters, I. M.

1999-12-01

48

Iron Chelation Therapy  

MedlinePLUS

... iron overload. What actually happens to cause iron overload? With each red blood cell transfusion, your body ... is deposited. What are the symptoms of iron overload? Early on, iron overload can cause no symptoms, ...

49

Iron and infection  

Microsoft Academic Search

Iron and infection. Intravenous iron therapy maintains iron stores and decreases erythropoietin demand in patients undergoing regular dialysis therapy. Microbiology studies show a close relationship between the availability of iron and bacterial virulence. Iron is also an essential requirement of bacteria for multiplication in the host. Therefore, clinical conditions associated with iron excess in the host may increase the risk

SANDA I. PATRUTA; WALTER H. HORL

1999-01-01

50

Iron and iron derived radicals  

SciTech Connect

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.

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

1987-04-01

51

The Integrated Field-Scale Subsurface Research Challenge Site (IFC) at Rifle, Colorado: Preliminary Results on Microbiological, Geochemical and Hydrologic Processes Controlling Iron Reduction and Uranium Mobility  

NASA Astrophysics Data System (ADS)

The IFC at Rifle, Colorado was recently funded by the U.S. Department of Energy to address knowledge gaps in 1) geochemical and microbial controls on stimulated U(VI) bioreduction by iron-reducers, 2) U(VI) sorption under Fe-reducing conditions, 3) post-biostimulation U(VI) stability and removal, and 4) rates of natural bioreduction of U(VI). The over-arching goal of the project is to develop a mechanistic understanding of bioreductive and abiotic processes that control uranium mobility targeting new knowledge that can be translated into scientifically defensible flow and reactive transport process models. The Rifle IFC will conduct a focused set of field and lab experiments that use recently developed sciences of proteogenomics and stable isotope probing to track microbial metabolic status during acetate amendment. This information will be linked to changes in Fe redox status and sulfide minerals, with field-scale changes detected by non-invasive hydrogeophysics, including 3-D resistivity tomography. A key goal of the project is to combine abiotic sorption processes under reducing conditions with biotic processes controlling U(VI) reduction. The initial field-scale experiment for the Rifle IFC was conducted during the summer of 2007 with the objectives of collecting simultaneous metagenomic and proteomic samples during acetate amendment and to assess the impact of intentionally decreasing electron donor concentration on the metabolic processes of iron reducers. The 2007 experiment replicated previous field experiments, producing dominance of Geobacter sp. in groundwater within 10 days after the start of acetate amendment. The experiment also confirmed the importance of heterogeneities in controlling the flux of electron donor and the impact of naturally reduced zones on the duration of Fe reduction.

Long, P. E.; Banfield, J.; Bush, R.; Campbell, K.; Chandler, D. P.; Davis, J. A.; Dayvault, R.; Druhan, J.; Elifantz, H.; Englert, A.; Hettich, R. L.; Holmes, D.; Hubbard, S.; Icenhower, J.; Jaffe, P. R.; Kerkhof, L. J.; Kukkadapu, R. K.; Lesher, E.; Lipton, M.; Lovley, D.; Morris, S.; Morrison, S.; Mouser, P.; Newcomer, D.; N'guessan, L.; Peacock, A.; Qafoku, N.; Resch, C. T.; Spane, F.; Spaulding, B.; Steefel, C.; Verberkmoes, N.; Wilkins, M.; Williams, K. H.; Yabusaki, S. B.

2007-12-01

52

Cellular iron metabolism  

Microsoft Academic Search

Cellular iron metabolism. Iron is essential for oxidation-reduction catalysis and bioenergetics, but unless appropriately shielded, iron plays a key role in the formation of toxic oxygen radicals that can attack all biological molecules. Hence, specialized molecules for the acquisition, transport (transferrin), and storage (ferritin) of iron in a soluble nontoxic form have evolved. Delivery of iron to most cells, probably

PREM PONKA

1999-01-01

53

Controversies in iron management  

Microsoft Academic Search

Controversies in iron management.BackgroundIron therapy is required in hemodialysis patients receiving erythropoietic stimulators in order to achieve the target hemoglobin in the most efficient way. While oral iron has been disappointing in this regard, parenteral iron has been widely used, despite a significant incidence of severe side effects when iron dextran is used. The recent availability of a more effective

Allen R. Nissenson; Chaim Charytan

2003-01-01

54

Nutritional iron deficiency  

Microsoft Academic Search

Iron deficiency is one of the leading risk factors for disability and death worldwide, affecting an estimated 2 billion people. Nutritional iron deficiency arises when physiological requirements cannot be met by iron absorption from diet. Dietary iron bioavailability is low in populations consuming monotonous plant-based diets. The high prevalence of iron deficiency in the developing world has substantial health and

Michael B Zimmermann; Richard F Hurrell

2007-01-01

55

Iron-Deficiency Anemia  

MedlinePLUS Videos and Cool Tools

... Research 4 Home » Health Information for the Public » Health Topics » Iron-Deficiency Anemia » What Is ... Iron-Deficiency Anemia Explore Iron-Deficiency Anemia What Is ... Causes Who Is at Risk Signs & Symptoms Diagnosis Treatments Prevention Living With Clinical ...

56

Iron Absorption by Infants.  

National Technical Information Service (NTIS)

The research team studied absorption of iron from carefully selected iron-fortified foods that are now commercially available or are attractive candidates for future iron fortification. Because of possible adverse interactions with zinc and copper when in...

S. J. Fomon

1995-01-01

57

Hemochromatosis: Iron Storage Disease  

MedlinePLUS

... body's tissues and organs, a term called iron overload. If this iron buildup is untreated, it can, ... Detected? If your doctor suspects you have iron overload associated with hemochromatosis, there are two blood tests – ...

58

HEPCIDIN AND IRON HOMEOSTASIS  

PubMed Central

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.

Ganz, Tomas; Nemeth, Elizabeta

2014-01-01

59

Iron speciation and dynamics during SERIES, a mesoscale iron enrichment experiment in the NE Pacific  

NASA Astrophysics Data System (ADS)

During the Sub-arctic Ecosystem Response to Iron Enrichment Study (SERIES), the addition of ferrous iron to high-nitrate low-chlorophyll (HNLC) waters near Ocean Station PAPA (OSP: 50°N, 145°W) produced a phytoplankton bloom and CO 2 drawdown, as evidenced by decreasing CO 2 fugacity ( fCO 2). We analyzed five fractions or phases of iron: soluble (<0.03 ?m), dissolved (<0.22 ?m), total dissolved (acidified dissolved, <0.22 ?m), labile (unfiltered), and total (acidified, unfiltered). From these, we also calculated non-labile iron, colloidal iron (0.03-0.22 ?m), and both labile and non-labile particulate iron (>0.22 ?m). Here, we describe iron distributions and the evolution of iron phases in the upper ocean during the experiment. We also present an iron budget accounting for horizontal and vertical dilution. At the time of our first sampling eight hours after fertilization was completed, total iron reached 8.6 nmol L -1 and dissolved iron was approximately 3 nmol L -1. Early in the experiment the dissolved iron phase decreased the most rapidly and by late day 6 the integrated dissolved iron (8.6 ?mol m -2) represented less than 10% of the initial addition (90-95 ?mol m -2). However at this same time the total integrated iron at the centre of the patch was still 52 ?mol m -2 or almost 60% of the calculated initial addition. By day 12,45% of the added iron (from both injections) could be accounted for in the patch. The half-life of total iron in the patch for the first injection was estimated to be less than 5 days if dilution is not considered, but more than 13 days if dilution is taken into account. The most notable change in iron percentages from one form to another occurred early in the first week of the experiment where the predominant phase shift was from the colloidal portion of dissolved iron to labile particulate iron that could have been biologically induced or simply aggregation of oxyhydroxides. This was immediately followed by a physical event resulting in a reduction in the non-labile particulate iron due to sinking out of the patch. The second infusion did not change the relative concentration of the various pools of iron as might be expected, but this was likely due to the fact that it was a much smaller injection than the first. The most pronounced change after the second infusion was the reduction in the labile particulate pool which coincided with one of the largest decreases in silicate observed during the entire experiment. In general the gradual decrease in the fraction of the 10 m colloidal iron as well as episodic losses of, or shifts in, integrated colloidal iron are thought to be the result of adsorption of colloidal iron to the plankton cell surfaces as well as aggregation of oxyhydroxides but could also be the result of utilization of colloidal iron by mixotrophic phytoplankton.

Wong, C. S.; Johnson, W. K.; Sutherland, N.; Nishioka, J.; Timothy, D. A.; Robert, M.; Takeda, S.

2006-10-01

60

Natural Resource Condition Assessment for Saugus Iron Works National Historic Site.  

National Technical Information Service (NTIS)

Saugus Iron Works National Historic Site (SAIR), a small, urban park located just outside of Boston, MA, preserves the site of Americas first sustained, integrated, and successful iron works. The primary natural resources of the park are the tidally influ...

M. J. James-Pirri P. D. Vaux S. J. Nelson

2011-01-01

61

Neuroimaging, nutrition, and iron-related genes.  

PubMed

Several dietary factors and their genetic modifiers play a role in neurological disease and affect the human brain. The structural and functional integrity of the living brain can be assessed using neuroimaging, enabling large-scale epidemiological studies to identify factors that help or harm the brain. Iron is one nutritional factor that comes entirely from our diet, and its storage and transport in the body are under strong genetic control. In this review, we discuss how neuroimaging can help to identify associations between brain integrity, genetic variations, and dietary factors such as iron. We also review iron's essential role in cognition, and we note some challenges and confounds involved in interpreting links between diet and brain health. Finally, we outline some recent discoveries regarding the genetics of iron and its effects on the brain, suggesting the promise of neuroimaging in revealing how dietary factors affect the brain. PMID:23817740

Jahanshad, Neda; Rajagopalan, Priya; Thompson, Paul M

2013-12-01

62

Iron metabolism and toxicity  

Microsoft Academic Search

Iron is an essential nutrient with limited bioavailability. When present in excess, iron poses a threat to cells and tissues, and therefore iron homeostasis has to be tightly controlled. Iron's toxicity is largely based on its ability to catalyze the generation of radicals, which attack and damage cellular macromolecules and promote cell death and tissue injury. This is lucidly illustrated

G. Papanikolaou; K.. Pantopoulos

2005-01-01

63

Nutritional iron deficiency.  

PubMed

Iron deficiency is one of the leading risk factors for disability and death worldwide, affecting an estimated 2 billion people. Nutritional iron deficiency arises when physiological requirements cannot be met by iron absorption from diet. Dietary iron bioavailability is low in populations consuming monotonous plant-based diets. The high prevalence of iron deficiency in the developing world has substantial health and economic costs, including poor pregnancy outcome, impaired school performance, and decreased productivity. Recent studies have reported how the body regulates iron absorption and metabolism in response to changing iron status by upregulation or downregulation of key intestinal and hepatic proteins. Targeted iron supplementation, iron fortification of foods, or both, can control iron deficiency in populations. Although technical challenges limit the amount of bioavailable iron compounds that can be used in food fortification, studies show that iron fortification can be an effective strategy against nutritional iron deficiency. Specific laboratory measures of iron status should be used to assess the need for fortification and to monitor these interventions. Selective plant breeding and genetic engineering are promising new approaches to improve dietary iron nutritional quality. PMID:17693180

Zimmermann, Michael B; Hurrell, Richard F

2007-08-11

64

Iron shielded MRI optimization  

NASA Astrophysics Data System (ADS)

The design of the main current systems of an actively shielded and of an iron shielded MRI device for nuclear resonance imaging, is considered. The model for the analysis of the magnetic induction produced by the current system, is based on the combination of a Boundary Element technique and of the integration of two Fredholm integral equations of the first and the second kind. The equivalent current magnetization model is used for the calculation of the magnetization produced by the iron shield. High field uniformity in a spherical region inside the device, and a low stray field in the neighborhood of the device are required. In order to meet the design requirements a multi-objective global minimization problem is solved. The minimization method is based on the combination of the filled function technique and the (1+1) evolution strategy algorithm. The multi-objective problem is treated by means of a penalty method. The actively shielded MRI system results to utilize larger amount of conductor and produce higher magnetic energy than the iron shield device. On veut étudier le projet du système des courants principaux d'un MRI à écran en fer et d'un MRI à écran actif. Le modèle d'analyse du champ magnétique produit par le système de courants est basé sur la combinaison d'une technique Boundary Element et de l'intégration de deux équations intégrales de Fredholm de première et de seconde sorte. On utilise pour calculer la magnétisation produite par l'écran en fer le modèle à cou rants de magné ti sa tion équivalents. On exige une élévation uniforme du champ dans une région sphérique au cœur de l'appareil et un bas champ magnétique dispersé à proximité de l'appareil. Dans le but de répondre aux impératifs du projet, on va résoudre un problème multiobjectif de minimisation globale. On utilise une technique de minimisation obtenue par la combinaison des méthodes “Filled Function” et “(1+1) Evolution Strategy”. Le problème multiobjectif est traité avec la méthode des pénalités. Il s'ensuit que le MRI à écran actif utilise une plus grande quantité de conducteur et produit une énergie magnétique plus élevée que le MRI à écran en fer.

Borghi, C. A.; Fabbri, M.

1998-09-01

65

Iron and copper release in drinking-water distribution systems.  

PubMed

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

Shi, Baoyou; Taylor, James S

2007-09-01

66

IRON IN MULTIPLE MYELOMA  

PubMed Central

Multiple myeloma is a non-curable B cell malignancy in which iron metabolism plays an important role. Patients with this disorder almost universally suffer from a clinically significant anemia, which is often symptomatic, and which is due to impaired iron utilization. Recent studies indicate that the proximal cause of dysregulated iron metabolism and anemia in these patients is cytokine-induced upregulation of hepcidin expression. Malignant myeloma cells are dependent on an increased influx of iron and therapeutic efforts are being made to target this requirement. The studies detailing the characteristics and biochemical abnormalities in iron metabolism causing anemia and the initial attempts to target iron therapeutically are described in this review.

VanderWall, Kristina; Daniels-Wells, Tracy R; Penichet, Manuel; Lichtenstein, Alan

2013-01-01

67

Ocean iron cycle  

NASA Astrophysics Data System (ADS)

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.

Boyd, Philip W.

68

Genetics Home Reference: Iron-refractory iron deficiency anemia  

MedlinePLUS

... PubMed Recent literature OMIM Genetic disorder catalog Conditions > Iron-refractory iron deficiency anemia On this page: Description Genetic changes ... names Glossary definitions Reviewed July 2014 What is iron-refractory iron deficiency anemia? Iron-refractory iron deficiency ...

69

Initial Oxidation of Iron and Iron Nitride.  

National Technical Information Service (NTIS)

Iron nitride layers on low alloyed steels are of interest because they improve their performance with respect to wear, fatigue and corrosion. Subjecting a nitrided workpiece to an oxidation treatment brings about an iron-oxide layer at the surface, which ...

P. Graat

1998-01-01

70

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

Microsoft Academic Search

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

F. Goto; T. Yoshihara; H. Saiki

2000-01-01

71

Latent Iron in Silicon  

Microsoft Academic Search

It is usually assumed that the iron in iron-contaminated, boron-doped silicon exists as FeB pairs. The iron can be cycled between its interstitial (Fei) and paired (FeB) states with the total density Fei+FeB remaining constant. We have discovered that iron can also exist in other paired states, which we believe to be Fe-vacancy or Fe-implant damage pairs. When these pairs

Byoung-Deog Choi; Dieter K. Schroder; Sergei Koveshnikov; Subhash Mahajan

2001-01-01

72

Iron fortification in dairy industry  

Microsoft Academic Search

Iron deficiency is usually the result of insufficient dietary intake of iron, poor utilization of iron from ingested food, or a combination of the two. Direct addition of iron to milk or dairy products might be an effective mean of increasing the dietary intake of iron to the general population. However, iron fortification of milk or dairy products induces several

Frédéric Gaucheron

2000-01-01

73

Minerals Yearbook, 1989: Slag-Iron and Steel.  

National Technical Information Service (NTIS)

Notable events in the iron and steel slag industry during 1989 included the acquisition of one of the Nation's largest slag companies and a major international concrete conference on natural pozzolans in which slag played an integral role. Research during...

J. F. Owens

1989-01-01

74

Neurodegeneration with brain iron accumulation: from genes to pathogenesis.  

PubMed

Neurodegeneration with brain iron accumulation comprises a clinically and genetically heterogeneous collection of disorders that share key features. These include progressive neurological disease accompanied by high basal ganglia iron and axonal dystrophy. To date, 2 genetic forms have been associated with mutations in PANK2 and PLA2G6, both of which encode proteins that are critical to membrane integrity. The intersection of pathways perturbed by defects in these 2 genes now enables us to test hypotheses of a common pathogenesis and ask why iron accumulates. The mechanisms implicated may contribute to our understanding of more common neurodegenerative disorders with iron dyshomeostasis, including Parkinson and Alzheimer disease. PMID:17101457

Hayflick, Susan J

2006-09-01

75

Thermodynamic properties of Iron—Tellurium alloys  

Microsoft Academic Search

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

H. Ipser; K. L. Komarek

1974-01-01

76

Molecular Structure of Iron  

NSDL National Science Digital Library

Since antiquity, Iron has been known for its malleability and abundance. Iron is a soft grey metal that is very ductile and easy to work; it can be rolled, hammered, bent, and tempered. Iron makes up 5% of the earth's crust in the form of ores such as hematite, limonite, magnetite, and taconite. This makes it the second most abundant metal, following aluminum. Most iron is used to manufacture carbon steel: iron with about 1.5% carbon and traces of other elements, but it is also used for many other alloys and steels of various types. Iron melts at 1808 degrees Kelvin and boils at 3023 degrees Kelvin. Insufficient iron in the bloodstream causes anemia, a medical condition causing unusual tiredness and other symptoms resulting from underdeveloped or few red blood cells.

2003-04-16

77

Iron metabolism and malaria.  

PubMed

Recent evidence from a large, randomized, controlled trial has suggested that the universal administration of iron to children in malaria-endemic areas is associated with an increase in adverse health outcomes. The purpose of this paper is to summarize the available ecologic and intervention trials related to iron and malaria in children, and to set these against current knowledge of the biology of host-pathogen interactions involving iron metabolism. We conclude that, although not fully consistent, the balance of evidence confirms that administration of iron (usually in combination with folic acid) increases the incidence of malaria when given without prophylaxis and in the absence of universal access to treatment. The mechanisms by which additional iron can benefit the parasite are far from clear. There is evidence to suggest that the apparent detrimental effect of iron supplementation may vary according to levels of antecedent iron status, the presence of hemoglobinopathies and glucose-6-phosphate dehydrogenase (G6PD) deficiency, and other host genetic variants, such as variants in haptoglobin. The effects of malaria on host iron metabolism are also reviewed and reveal that the key cause of malaria-induced anemia is a maldistribution of iron and suppression of erythropoiesis rather than an exacerbation of gross iron deficiency. We tentatively conclude that, if it is to be recommended, universal iron supplementation in malarious areas should only be considered in conjunction with some form of prophylaxis (e.g., intermittent preventive therapy [IPT]) or in the context of good health services with ready access to facilities for malaria diagnosis and treatment. An alternative approach would be to screen for anemia and target supplementation only to anemic children. With regard to treatment, there is good evidence that iron supplementation should be withheld until the treatment schedule is complete, both because iron may inhibit treatment and because the absorption of oral iron is blocked by the inflammatory response. PMID:18297891

Prentice, Andrew M; Ghattas, Hala; Doherty, Conor; Cox, Sharon E

2007-12-01

78

The ubiquity of iron.  

PubMed

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

Frey, Perry A; Reed, George H

2012-09-21

79

Iron and intestinal immunity  

PubMed Central

Purpose of review Recent advances in the study of iron metabolism have led to a better understanding of the molecular basis for the interactions between iron and the inflammatory response. We will review this new information in the context of the gastrointestinal tract. Recent findings The effects of iron on microbial enteropathogens are well known. Recent work has demonstrated that iron also has potentially important effects on the intestinal microbiota. On the host side, hepcidin, a key regulator of mammalian iron metabolism, has emerged as an important mediator of the cross-talk between iron homeostasis and inflammation. Hepcidin-dependent changes in iron flux can influence the expression of inflammatory cytokines, and conversely, inflammatory cytokines can induce hepcidin expression and alter iron homeostasis. Hepcidin levels have been found to be elevated in some studies of inflammatory bowel disease, while manipulating hepcidin expression in animal models of this condition has beneficial effects on both inflammation and dysregulated iron metabolism. Summary The information on iron metabolism that has become available in recent years has shed new light on the pathogenesis of inflammatory diseases of the gastrointestinal tract, and is also starting to suggest new approaches to treating such diseases.

Cherayil, Bobby J.; Ellenbogen, Shiri; Shanmugam, Nandakumar N.

2013-01-01

80

Iron-Air Rechargeable Battery: A Robust and Inexpensive Iron-Air Rechargeable Battery for Grid-Scale Energy Storage  

SciTech Connect

GRIDS Project: USC is developing an iron-air rechargeable battery for large-scale energy storage that could help integrate renewable energy sources into the electric grid. Iron-air batteries have the potential to store large amounts of energy at low cost—iron is inexpensive and abundant, while oxygen is freely obtained from the air we breathe. However, current iron-air battery technologies have suffered from low efficiency and short life spans. USC is working to dramatically increase the efficiency of the battery by placing chemical additives on the battery’s iron-based electrode and restructuring the catalysts at the molecular level on the battery’s air-based electrode. This can help the battery resist degradation and increase life span. The goal of the project is to develop a prototype iron-air battery at significantly cost lower than today’s best commercial batteries.

None

2010-10-01

81

Marginally excessive iron loading transiently blocks mucosal iron uptake in iron-deficient rats.  

PubMed

Regular "mucosal block" is characterized by decreased uptake of a normal iron load 3-72 h after the administration of excess iron (generally 10 mg) to iron-deficient animals. We found that short-acting mucosal block could be induced by much lower iron concentration and much shorter induction time than previously reported, without affecting levels of gene expression. A rapid endocytic mechanism was reported to decrease intestinal iron absorption after a high iron load, but the activating iron load and the time to decreased absorption were undetermined. We assessed the effects of 30-2,000 ?g iron load on iron uptake in the duodenal loop of iron-deficient and iron-sufficient rats under anesthesia. One hour later, mucosal cellular iron uptake in iron-deficient rats administered 30 ?g iron was 76.1%, decreasing 25% to 50.7% in rats administered 2,000 ?g iron. In contrast, iron uptake by iron-sufficient rats was 63% (range 60.3-65.5%) regardless of iron load. Duodenal mucosal iron concentration was significantly lower in iron-deficient than in iron-sufficient rats. Iron levels in portal blood were consistently higher in iron-deficient rats regardless of iron load, in contrast to the decreased iron uptake on the luminal side. Iron loading blocked mucosal uptake of marginally excess iron (1,000 ?g), with a greater effect at 15 min than at 30 min. The rapid induction of short-acting mucosal block only in iron-deficient rats suggests DMT1 internalization. PMID:24833704

Shinoda, Shoko; Yoshizawa, Shiho; Nozaki, Eriko; Tadai, Kouki; Arita, Anna

2014-07-01

82

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

PubMed

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

Bonnefoy, Violaine; Holmes, David S

2012-07-01

83

Iron Storage in Bacteria  

Microsoft Academic Search

Iron is an essential nutrient for nearly all organisms but presents problems of toxicity, poor solubility and low availability. These problems are alleviated through the use of iron-storage proteins. Bacteria possess two types of iron-storage protein, the haemcontaining bacterioferritins and the haem-free ferritins. These proteins are widespread in bacteria, with at least 39 examples known so far in eubacteria and

Simon C. Andrews

1998-01-01

84

Iron (III) isomaltoside 1000.  

PubMed

Intravenous (iv.) iron is now the recommended treatment for iron deficiency anemia if oral preparations have failed or in those undergoing hemodialysis. Iron isomaltoside is a new iv. iron preparation, licensed since 2009 in the UK and Europe. The iron is tightly bound within a nonionic isomaltoside carbohydrate matrix, as opposed to most other iv. iron preparations that use branched polymers to form a carbohydrate shell. This conformation produces a low immunogenic potential, which allows high single-dose infusions to adequately replenish stores. Two Phase III, open-label, noncomparative, multicenter clinical trials have investigated the safety profile of iron isomaltoside in chronic kidney disease and chronic heart failure. Two serious adverse events were observed (Staphylococcus aureus sepsis and angina pectoris), although their relationship to the drug was questioned. Significant hemoglobin and serum ferritin rises were seen in the chronic kidney disease group. The chronic heart failure group showed a significant serum ferritin rise and improved 'overall quality of life' but a nonsignificant hemoglobin rise. Preparations of iv. iron can cause renal injury, possibly through oxidative stress. Modern preparations, such as iron isomaltoside and ferumoxytol, have demonstrated less free iron release and hence may theoretically cause less renal damage. The cost of iron isomaltoside is greater than some of the current standard preparations used in most hospitals in the UK and Europe. However, when overheads and patient throughput are calculated, it may be a more cost-effective therapy than current therapies in the UK, owing to its faster infusion rate. Currently, there remains limited data on efficacy, safety and cost-effectiveness. Although initial data are encouraging, they come from only three published small trials, thus restricting the conclusions that can be made. Future research needs to concentrate on comparative analyses with other iv. iron therapies. PMID:23782077

Mace, Thomas A R; Syed, Ahsan; Bhandari, Sunil

2013-06-01

85

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

86

Iron deficiency: beyond anemia.  

PubMed

Iron deficiency is the most common nutritional disorder affecting at least one third of world's population. Though anemia is common manifestation of iron deficiency, other effects of iron deficiency on various tissues, organs and systems are usually under recognized. Impaired brain development and cognitive, behavioural and psychomotor impairment are most worrisome manifestations of iron deficiency. Studies have demonstrated that some of these changes occurring during period of brain growth spurt (<2 years age) may be irreversible. Association of iron deficiency with febrile seizures, pica, breath holding spells, restless leg syndrome and thrombosis is increasingly being recognized. Impaired cell-mediated immunity and bactericidal function are generally noted in iron-deficient persons; however, the findings are inconsistent. Despite proven reversible functional immunological defects in vitro studies, a clinically important relationship between states of iron deficiency and susceptibility to infections remains controversial. Studies from malaria endemic regions have reported increased incidence of malaria in association with iron supplementation. These and some other aspects of iron deficiency are reviewed in this article. PMID:20814842

Yadav, Dinesh; Chandra, Jagdish

2011-01-01

87

Physics of iron  

SciTech Connect

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.

Anderson, O.

1993-10-01

88

Physiology of Iron Metabolism  

PubMed Central

Summary 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.

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

2014-01-01

89

Iron, Meat and Health  

PubMed Central

This article is a summary of the publication “Iron and Health” by the Scientific Advisory Committee on Nutrition (SACN) to the U.K. Government (2010), which reviews the dietary intake of iron and the impact of different dietary patterns on the nutritional and health status of the U.K. population. It concludes that several uncertainties make it difficult to determine dose-response relationships or to confidently characterize the risks associated with iron deficiency or excess. The publication makes several recommendations concerning iron intakes from food, including meat, and from supplements, as well as recommendations for further research.

Geissler, Catherine; Singh, Mamta

2011-01-01

90

Intraluminal Factors Affecting Iron Absorption.  

National Technical Information Service (NTIS)

The simplest model of iron absorption must consider (1) the mucosal uptake of dietary iron and (2) the transfer of iron from intestinal cells into the body. It provides three anatomic locations for studying regulatory factors: (a) intraluminal, (b) duoden...

M. E. Conrad

1968-01-01

91

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

SciTech Connect

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.

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

1983-03-28

92

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

...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...

2014-04-01

93

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

Code of Federal Regulations, 2011 CFR

...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...

2011-04-01

94

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

Code of Federal Regulations, 2012 CFR

...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...

2012-04-01

95

Thin Wall Iron Castings  

SciTech Connect

Results of an investigation made to develop methods of making iron castings having wall thicknesses as small as 2.5 mm in green sand molds are presented. It was found that thin wall ductile and compacted graphite iron castings can be made and have properties consistent with heavier castings. Green sand molding variables that affect casting dimensions were also identified.

J.F. Cuttino; D.M. Stefanescu; T.S. Piwonka

2001-10-31

96

The case for iron  

Microsoft Academic Search

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

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

1991-01-01

97

The Rusting of Iron  

Microsoft Academic Search

DURING the past few months the study of the chemical changes involved in the rusting of iron has been coming to the fore. In 1888 Crum Brown pointed out that iron remained free from rust in an atmosphere of oxygen carbon dioxide, and water vapour so long as liquid water was prevented from condensing on its surface. Whitney, in 1903,

J. Newton Friend

1906-01-01

98

Iron studies in hemophilia  

SciTech Connect

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.

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

1981-12-01

99

Iron economy in Chlamydomonas reinhardtii  

PubMed Central

While research on iron nutrition in plants has largely focused on iron-uptake pathways, photosynthetic microbes such as the unicellular green alga Chlamydomonas reinhardtii provide excellent experimental systems for understanding iron metabolism at the subcellular level. Several paradigms in iron homeostasis have been established in this alga, including photosystem remodeling in the chloroplast and preferential retention of some pathways and key iron-dependent proteins in response to suboptimal iron supply. This review presents our current understanding of iron homeostasis in Chlamydomonas, with specific attention on characterized responses to changes in iron supply, like iron-deficiency. An overview of frequently used methods for the investigation of iron-responsive gene expression, physiology and metabolism is also provided, including preparation of media, the effect of cell size, cell density and strain choice on quantitative measurements and methods for the determination of metal content and assessing the effect of iron supply on photosynthetic performance.

Glaesener, Anne G.; Merchant, Sabeeha S.; Blaby-Haas, Crysten E.

2013-01-01

100

Seminar on Role of Copper and Copper Alloys in Iron and Steel Industry. Proceedings of the Seminar Held in Calcutta, August 18, 1978.  

National Technical Information Service (NTIS)

Various papers presented at the seminar covered the following topics: Use of Copper in Integrated Iron and Steel works; Copper Base Components in Iron & Steel Industries - Problems and Prospects in India; Steel Plant Requirements of High Conductivity Copp...

1978-01-01

101

[Diagnosis of iron overload syndrome].  

PubMed

The article presents a classification of conditions, accompanied with increasing of iron accumulation of the liver cells, normal iron metabolism in the human body, etiology, epidemiology, multifactorial structure of the pathogenesis of HFE homozygous hemochromatosis, clinic of iron overload syndrome. The modern algorithms of diagnostic and tactics of patients with the use of genotyping and correction of iron content. PMID:20731136

Polunina, T E; Maev, I V

2010-01-01

102

Coal desulfurization. [using iron pentacarbonyl  

NASA Technical Reports Server (NTRS)

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.

Hsu, G. C. (inventor)

1979-01-01

103

Molecular Structure of Iron Monoxide  

NSDL National Science Digital Library

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.

2003-06-04

104

Reactive iron in marine sediments  

NASA Technical Reports Server (NTRS)

The influence of reactive iron oxides on sediment pore-water chemistry is considered in detail. A carefully calibrated extraction scheme is used to determine the depth distributions of reactive iron phases at two very different localities: the relatively iron-rich Mississippi Delta and the relatively iron-poor FOAM site in Long Island Sound. Closed system incubations are used to characterize the rates of reaction between sulfide and both naturally occurring and pure iron mineral phases. Rates of iron liberation to pore solution are measured in the presence and absence of sulfate reduction, and the origin of dissolved iron in organic-rich sediments is speculated upon.

Canfield, Donald E.

1989-01-01

105

Perturbation theory of iron-pnictide superconductivity  

NASA Astrophysics Data System (ADS)

To study the high-T superconductivity in iron pnictides, we solve the Eliashberg equation for a five-orbital Hubbard model by expanding the pairing interaction perturbatively to third order in the on-site Coulomb integrals. The most favorable pairing symmetry is an s±-wave with sign change of the order parameter between the hole and electron pockets. It is suggested that the superconductivity disappears in high-doping regions where the electron pockets or the hole pockets disappear.

Nomura, Takuji

2010-12-01

106

Laser-modified aluminium surfaces with iron  

Microsoft Academic Search

Possible improvements in the mechanical properties of surface-coated aluminium have been investigated. Aluminium plasma sprayed with iron powder was processed using two different laser-beam settings (integrated and defocused) with varying processing parameters. Mechanical and microstructural characterizations of the specimens revealed great differences between the two laser-beam settings. The defocused laser beam showed a clear improvement of hardness which was not

L. Gjønnes; A. Olsen

1994-01-01

107

An Ancient Gauge for Iron  

NSDL National Science Digital Library

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.

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

2009-10-30

108

Iron Dominated Magnets.  

National Technical Information Service (NTIS)

These two lectures on iron dominated magnets are meant for the student of accelerator science and contain general treatments of the subjects design and construction. The material is arranged in the categories: General Concepts and Cost Considerations, Pro...

G. E. Fischer

1985-01-01

109

Taking iron supplements  

MedlinePLUS

... If constipation becomes a problem, take a stool softener such as docusate sodium (Colace). Nausea and vomiting ... stain your teeth. Try mixing the iron with water or other liquids (such as fruit juice or ...

110

The IRON project  

NASA Astrophysics Data System (ADS)

The international computational consortium referred to as the IRON Project is briefly described, emphasizing the current astrophysical needs for accurate Fe atomic data. The computational framework and the physical effects that must be taken into account are also discussed.

Mendoza, C.

1999-09-01

111

Iron homeostasis in the liver  

PubMed Central

Iron is an essential nutrient that is tightly regulated. A principal function of the liver is the regulation of iron homeostasis. The liver senses changes in systemic iron requirements and can regulate iron concentrations in a robust and rapid manner. The last 10 years have led to the discovery of several regulatory mechanisms in the liver which control the production of iron regulatory genes, storage capacity, and iron mobilization. Dysregulation of these functions leads to an imbalance of iron, which is the primary causes of iron-related disorders. Anemia and iron overload are two of the most prevalent disorders worldwide and affect over a billion people. Several mutations in liver-derived genes have been identified, demonstrating the central role of the liver in iron homeostasis. During conditions of excess iron, the liver increases iron storage and protects other tissues, namely the heart and pancreas from iron-induced cellular damage. However, a chronic increase in liver iron stores results in excess reactive oxygen species production and liver injury. Excess liver iron is one of the major mechanisms leading to increased steatohepatitis, fibrosis, cirrhosis, and hepatocellular carcinoma.

Anderson, Erik R; Shah, Yatrik M

2014-01-01

112

Iron in the brain  

NASA Astrophysics Data System (ADS)

The results of our studies of iron in three brain structures, substantia nigra (SN), globus pallidus (GP), and hippocampus (Hip), are presented. Mössbauer spectroscopy, electron microscopy and ELISA (enzyme-linked immuno-absorbent assay) were applied. Mössbauer studies show that most of the iron in the brain is ferritin-like. The concentration of iron is similar in SN and GP, but less than half of this in Hip. ELISA studies showed that the H/L ratio of ferritin in SN and GP is also similar, but is about three times higher in Hip. These results suggest that the role of iron in SN and GP may be different from that in Hip. Electron microscopy shows that the diameters of the ferritin iron cores in the brain are smaller that in the liver (3.5 ± 0.5 nm vs. 6.0 ± 0.5 nm). Mössbauer studies yield the ratio between the concentration of iron in control and parkinsonian SN as 1.00 ± 0.13.

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

2009-02-01

113

Pancreatic iron loading predicts cardiac iron loading in thalassemia major.  

PubMed

Diabetes mellitus and cardiomyopathy are common in chronically transfused thalassemia major patients, occurring in the second and third decades of life. We postulated that pancreatic iron deposition would precede cardiac iron loading, representing an environment favorable for extrahepatic iron deposition. To test this hypothesis, we examined pancreatic and cardiac iron in 131 thalassemia major patients over a 4-year period. Cardiac iron (R2* > 50 Hz) was detected in 37.7% of patients and pancreatic iron (R2* > 28 Hz) in 80.4% of patients. Pancreatic and cardiac R2* were correlated (r(2) = 0.52), with significant pancreatic iron occurring nearly a decade earlier than cardiac iron. A pancreatic R2* less than 100 Hz was a powerful negative predictor of cardiac iron, and pancreatic R2* more than 100 Hz had a positive predictive value of more than 60%. In serial analysis, changes in cardiac iron were correlated with changes in pancreatic iron (r(2) = 0.33, P < .001), but not liver iron (r(2) = 0.025, P = .25). As a result, pancreatic R2* measurements offer important early recognition of physiologic conditions suitable for future cardiac iron deposition and complementary information to liver and cardiac iron during chelation therapy. Staging abdominal and cardiac magnetic resonance imaging examinations could significantly reduce costs, magnet time, and need for sedation in young patients. PMID:19726718

Noetzli, Leila J; Papudesi, Jhansi; Coates, Thomas D; Wood, John C

2009-11-01

114

Iron Absorption in Drosophila melanogaster  

PubMed Central

The way in which Drosophila melanogaster acquires iron from the diet remains poorly understood despite iron absorption being of vital significance for larval growth. To describe the process of organismal iron absorption, consideration needs to be given to cellular iron import, storage, export and how intestinal epithelial cells sense and respond to iron availability. Here we review studies on the Divalent Metal Transporter-1 homolog Malvolio (iron import), the recent discovery that Multicopper Oxidase-1 has ferroxidase activity (iron export) and the role of ferritin in the process of iron acquisition (iron storage). We also describe what is known about iron regulation in insect cells. We then draw upon knowledge from mammalian iron homeostasis to identify candidate genes in flies. Questions arise from the lack of conservation in Drosophila for key mammalian players, such as ferroportin, hepcidin and all the components of the hemochromatosis-related pathway. Drosophila and other insects also lack erythropoiesis. Thus, systemic iron regulation is likely to be conveyed by different signaling pathways and tissue requirements. The significance of regulating intestinal iron uptake is inferred from reports linking Drosophila developmental, immune, heat-shock and behavioral responses to iron sequestration.

Mandilaras, Konstantinos; Pathmanathan, Tharse; Missirlis, Fanis

2013-01-01

115

Bicarbonate-Induced Iron Complexes and Iron Absorption: One Effect of Pancreatic Secretions.  

National Technical Information Service (NTIS)

The addition of sodium bicarbonate to iron solutions produces both soluble macromolecular iron chelates and iron precipitates and causes decreased absorption of test doses of iron by normal guinea pigs. Similar physicochemical changes occur when iron solu...

B. I. Benjamin S. Cortell M. E. Conrad

1967-01-01

116

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

Microsoft Academic Search

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

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

1996-01-01

117

Hepcidin response to acute iron intake and chronic iron loading in dysmetabolic iron overload syndrome  

PubMed Central

Background The pathogenesis of dysmetabolic iron overload syndrome (DIOS) is still unclear. Hepcidin is the key regulator of iron homeostasis controlling iron absorption and macrophage release. Aim To investigate hepcidin regulation by iron in DIOS. Methods We analysed urinary hepcidin at baseline and 24 h after a 65 mg oral iron dose in 24 patients at diagnosis and after iron depletion (n=13) and compared data with those previously observed in 23 healthy controls. Serum iron indices, liver histology and metabolic data were available for all patients. Results At diagnosis, hepcidin values were significantly higher than in controls (P<0.001). After iron depletion, hepcidin levels decreased to normal values in all patients. At baseline, a significant response of hepcidin to iron challenge was observed only in the subgroup with lower basal hepcidin concentration (P=0.007). In iron-depleted patients, urinary hepcidin significantly increased after oral iron test (P=0.006). Conclusions Ours findings suggest that in DIOS, the progression of iron accumulation is counteracted by the increase in hepcidin production and progressive reduction of iron absorption, explaining why these patients develop a mild–moderate iron overload that tends to a plateau.

Trombini, Paola; Paolini, Valentina; Pelucchi, Sara; Mariani, Raffaella; Nemeth, Elizabeta; Ganz, Tomas; Piperno, Alberto

2014-01-01

118

Determination of iron in solutions containing iron complexes  

Microsoft Academic Search

A method of estimating the iron content of solutions containing haemoglobin, ferritin, or ferrioxamine is described. Iron is released by treatment with acid permanganate and ascorbic acid before conventional determination by an Auto Analyzer technique.

G. B. Tennant; D. A. Greenman

1969-01-01

119

Forging the anthropogenic iron cycle.  

PubMed

Metallurgical iron cycles are characterized for four anthropogenic life stages: production, fabrication and manufacturing, use, and waste management and recycling. This analysis is conducted for year 2000 and at three spatial levels: 68 countries and territories, nine world regions, and the planet. Findings include the following: (1) contemporary iron cycles are basically open and substantially dependent on environmental sources and sinks; (2) Asia leads the world regions in iron production and use; Oceania, Latin America and the Caribbean, Africa, and the Commonwealth of Independent States present a highly production-biased iron cycle; (3) purchased scrap contributes a quarter of the global iron and steel production; (4) iron exiting use is three times less than that entering use; (5) about 45% of global iron entering use is devoted to construction, 24% is devoted to transport equipment, and 20% goes to industrial machinery; (6) with respect to international trade of iron ore, iron and steel products, and scrap, 54 out of the 68 countries are net iron importers, while only 14 are net exporters; (7) global iron discharges in tailings, slag, and landfill approximate one-third of the iron mined. Overall, these results provide a foundation for studies of iron-related resource policy, industrial development, and waste and environmental management. PMID:17711233

Wang, Tao; Müller, Daniel B; Graedel, T E

2007-07-15

120

Iron–sulphur cluster biogenesis and mitochondrial iron homeostasis  

Microsoft Academic Search

Iron–sulphur clusters are important cofactors for proteins that are involved in many cellular processes, including electron transport, enzymatic catalysis and regulation. The enzymes that catalyse the formation of iron–sulphur clusters are widely conserved from bacteria to humans. Recent studies in model systems and humans reveal that iron–sulphur proteins have important roles in mitochondrial iron homeostasis and in the pathogenesis of

Tracey A. Rouault; Wing-Hang Tong

2005-01-01

121

Iron biomineralization by anaerobic neutrophilic iron-oxidizing bacteria  

Microsoft Academic Search

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).

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

122

Iron availability, cellular iron quotas, and nitrogen fixation in Trichodesmium  

Microsoft Academic Search

Iron availability is suggested to be a primary factor limiting nitrogen fixation in the oceans. This hypothesis is principally based on cost-benefit analyses of iron quotas in the dominant nitrogen-fixing cyanobacteria,Trichodesmium spp., in the contemporary oceans. Although previous studies with Trichodesmium have indicated that iron availability enhanced nitrogen fixation and photosynthesis, no clear relationship has been reported between cellular iron

Ilana Berman-Frank; Jay T. Cullen; Yeala Shaked; Robert M. Sherrell; Paul G. Falkowski

2001-01-01

123

Utilization of Industrial Waste Heat, Citing an Integrated Iron and Steel Works as an Example to Save Primary Energy and to Reduce the Burden on the Environment, Volume 1.  

National Technical Information Service (NTIS)

The utilization of waste heat to substitute primary energy is an essential factor to complement the savings of primary energy achieved by changes in the design of industrial plant and processes. The potential for waste energy utilization in an integrated ...

H. G. Poettken H. Strohschein

1982-01-01

124

Iron Science Teacher!  

NSDL National Science Digital Library

Every weekend during the summer, crowds gather at San Francisco's Exploratorium to watch the "Iron Science Teacher" game. Based on the wildly popular Japanese TV show, Iron Chef, in which chefs compete to see who can whip up the most creative and delicious meal with the day's "secret ingredient," Iron Science Teacher asks primary and secondary science educators to whip up a science lesson based on a "secret ingredient" -- be it PVC pipe, pantyhose, toothpicks or even marshmallow peeps! The goal of the project is to celebrate science education and to demonstrate that teachers can teach the $10 million state science standards on a $10 budget. Web surfers who can't make it to the Exploratorium can view this wacky yet totally educational program online. An archive of 25 broadcasts from June 1999 to the present is available (RealPlayer).

1998-01-01

125

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

126

Treatment of Iron Deficiency Anemia with Intravenous Iron Preparations  

Microsoft Academic Search

Objective: We aimed to determine the effects of intravenous iron therapy on blood parameters in pediatric patients who do not tolerate oral iron therapy for any reason. Patients and Methods: The patient group consisted of candidates for elective operations requiring blood transfusions in order to raise hemoglobin (Hb) concentrations rapidly and for whom oral iron administration is useless and compliance

Saadet Akarsu; Erdal Taskin; Erdal Yilmaz; Huseyin Yilmaz; Mehmet Kilic; A. Denizmen Aygun

2006-01-01

127

Cooling rates of 27 iron and stony-iron meteorites  

Microsoft Academic Search

A method for the precise determination of the cooling rates of iron and stony-iron meteorites has been developed and applied to 18 irons, 8 pallasites, and the siderophyre Steinbach. The cooling rates are determined by comparing the measured Ni gradients in several kamacitetaenite areas which result from the growth of the Widmanstätten structure between 700 and 300°C with gradients calculated

Joseph I. Goldstein; James M. Short

1967-01-01

128

The Iron-Storage Diseases.  

National Technical Information Service (NTIS)

Idiopathic, generalized, massive iron overloading (hemochromatosis) is a familial disorder in which excessive amounts of dietary iron are absorbed and accumulate in various organs of the body to produce tissue damage. Usually, the disease becomes manifest...

M. E. Conrad

1968-01-01

129

Iron in Infection and Immunity  

PubMed Central

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.

Cassat, James E.; Skaar, Eric P.

2013-01-01

130

Iron Nutrition, Immunity and Infection.  

National Technical Information Service (NTIS)

During infection, physiological mechanisms withhold iron from invading microorganisms by sequestering it in tissue stores. These mechanisms increase the concentration of unsaturated transferrin in plasma by reducing plasma iron values. In contrast to the ...

W. R. Beisel

1980-01-01

131

Iron Meteorite on Mars  

NASA Technical Reports Server (NTRS)

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.

2005-01-01

132

Nonbiological fractionation of iron isotopes  

NASA Technical Reports Server (NTRS)

Laboratory experiments demonstrate that iron isotopes can be chemically fractionated in the absence of biology. Isotopic variations comparable to those seen during microbially mediated reduction of ferrihydrite are observed. Fractionation may occur in aqueous solution during equilibration between inorganic iron complexes. These findings provide insight into the mechanisms of iron isotope fractionation and suggest that nonbiological processes may contribute to iron isotope variations observed in sediments.

Anbar, A. D.; Roe, J. E.; Barling, J.; Nealson, K. H.

2000-01-01

133

Ovotransferrin with One Iron Atom  

Microsoft Academic Search

TRANSFERRINS are iron-binding proteins which can carry a maximum of two atoms of iron per mole protein. If a preparation of hen ovotransferrin is incompletely saturated with iron and subjected to isoelectric focusing three main protein fractions are observed1. The most acidic fraction (pHI 5.78) is the protein complex with two iron atoms, and the most alkaline fraction (pHI 6.73)

J. Williams; C. F. Phelps; J. M. Lowe

1970-01-01

134

Viral infection and iron metabolism  

Microsoft Academic Search

Fundamental cellular operations, including DNA synthesis and the generation of ATP, require iron. Viruses hijack cells in order to replicate, and efficient replication needs an iron-replete host. Some viruses selectively infect iron-acquiring cells by binding to transferrin receptor 1 during cell entry. Other viruses alter the expression of proteins involved in iron homeostasis, such as HFE and hepcidin. In HIV-1

Hal Drakesmith; Andrew Prentice

2008-01-01

135

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

NASA Technical Reports Server (NTRS)

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.

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

2003-01-01

136

Iron storage in Mycoplasma capricolum.  

PubMed Central

Considerable quantities or iron were incorporated into the Mycoplasma capricolum cell membrane. Mossbauer studies showed that the iron is in a form which becomes magnetically ordered at low temperatures. The iron-enriched cells contained membrane-bound electron-dense particles of about 6.0 nm in diameter. Images

Bauminger, E R; Cohen, S G; Labenski de Kanter, F; Levy, A; Ofer, S; Kessel, M; Rottem, S

1980-01-01

137

Iron cofactor assembly in plants.  

PubMed

Iron is an essential element for all photosynthetic organisms. The biological use of this transition metal is as an enzyme cofactor, predominantly in electron transfer and catalysis. The main forms of iron cofactor are, in order of decreasing abundance, iron-sulfur clusters, heme, and di-iron or mononuclear iron, with a wide functional range. In plants and algae, iron-sulfur cluster assembly pathways of bacterial origin are localized in the mitochondria and plastids, where there is a high demand for these cofactors. A third iron-sulfur cluster assembly pathway is present in the cytosol that depends on the mitochondria but not on plastid assembly proteins. The biosynthesis of heme takes place mainly in the plastids. The importance of iron-sulfur cofactors beyond photosynthesis and respiration has become evident with recent discoveries of novel iron-sulfur proteins involved in epigenetics and DNA metabolism. In addition, increased understanding of intracellular iron trafficking is opening up research into how iron is distributed between iron cofactor assembly pathways and how this distribution is regulated. PMID:24498975

Balk, Janneke; Schaedler, Theresia A

2014-04-29

138

Pollution Effects of Abnormal Operations in Iron and Steel Making. Volume 1. Technical Report.  

National Technical Information Service (NTIS)

The report is the first 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...

B. H. Carpenter D. W. VanOsdell D. W. Coy R. Jablin

1978-01-01

139

Epitaxial Iron Films.  

National Technical Information Service (NTIS)

The research program focused on the growth and the magnetic properties of epitaxial iron films grown on GaAs/InAs alloy substrates. Pseudomorphic growth of magnetic films on semiconductor substrates provides the potential for tuning of the magnetic proper...

E. D. Dahlberg P. I. Cohen

1989-01-01

140

Iron dominated magnets  

Microsoft Academic Search

These two lectures on iron dominated magnets are meant for the student of accelerator science and contain general treatments of magnet design and construction. The areas covered are general concepts and cost considerations, profile configuration and harmonics, magnetic measurements, a few examples of ‘‘special magnets,’’ and materials and practices. An extensive list of references is provided.

G. E. Fischer

1987-01-01

141

Iron dominated magnets  

Microsoft Academic Search

These two lectures on iron dominated magnets are meant for the student of accelerator science and contain general treatments of magnet design and construction. The areas covered are general concepts and cost considerations, profile configuration and harmonics, magnetic measurements, a few examples of ``special magnets,'' and materials and practices. An extensive list of references is provided.

G. E. Fischer

1987-01-01

142

Iron dominated resistive magnets  

SciTech Connect

This paper starts with a review of Amperes Law and Potential Theory (Perfect Iron). It then proceeds to a discussion of Magnet Ends and on to Curved Magnets, Coil Construction, and Core Construction. It concludes with a discussion of Quality Control Methods and Examples of Recent Magnets Built.

Fred E. Mills

1999-06-03

143

Iron dominated resistive magnets  

Microsoft Academic Search

This paper starts with a review of Amperes Law and Potential Theory (Perfect Iron). It then proceeds to a discussion of Magnet Ends and on to Curved Magnets, Coil Construction, and Core Construction. It concludes with a discussion of Quality Control Methods and Examples of Recent Magnets Built.

Fred E. Mills

1999-01-01

144

Iron dominated magnets  

Microsoft Academic Search

These two lectures on iron dominated magnets are meant for the student of accelerator science and contain general treatments of the subjects design and construction. The material is arranged in the categories: General Concepts and Cost Considerations, Profile Configuration and Harmonics, Magnetic Measurements, a few examples of special magnets and Materials and Practices. Extensive literature is provided.

G. E. Fischer

1985-01-01

145

Iron dominated magnets  

SciTech Connect

These two lectures on iron dominated magnets are meant for the student of accelerator science and contain general treatments of the subjects design and construction. The material is arranged in the categories: General Concepts and Cost Considerations, Profile Configuration and Harmonics, Magnetic Measurements, a few examples of ''special magnets'' and Materials and Practices. Extensive literature is provided.

Fischer, G.E.

1985-07-01

146

Iron Sucrose Injection  

MedlinePLUS

Iron sucrose injection comes as a solution (liquid) to inject intravenously (into a vein) by a doctor or nurse in a medical office or hospital outpatient clinic. It is usually injected over 2 ... number of doses based on your condition and how well you respond to the ...

147

Iron ERRs with Salmonella.  

PubMed

The hormone hepcidin promotes iron sequestration by macrophages. A recent study by Kim et al. (2014) implicates the orphan receptor ERR? (estrogen-related receptor ?) in the regulation of hepcidin production and suggests that targeting the ERR?-hepcidin axis may be beneficial during infection with the facultative intracellular pathogen Salmonella. PMID:24832443

Fang, Ferric C; Weiss, Günter

2014-05-14

148

Iron monoxide photodissociation.  

PubMed

The photodissociation of (56)FeO was studied by means of the velocity map imaging technique. A molecular beam of iron atoms and iron monoxide molecules was created using an electrical discharge with an iron electrode in a supersonic expansion of molecular oxygen. The ground state iron atom Fe((5)D(4)) and FeO concentrations in the molecular beam have been estimated. The dissociation energy of the FeO X (5)Delta ground electronic state was found to be D(0) (0)(FeO)=4.18+/-0.01 eV. The effective absorption cross section of FeO at 252.39 nm (vac), leading to the Fe((5)D(4))+O((3)P) dissociation channel, is approximately 1.2 x 10(-18) cm(2). A (1+1) resonantly enhanced multiphoton ionization spectrum of (56)FeO in the region 39 550-39 580 cm(-1) with rotational structure has been observed, but not assigned. Angular distributions of Fe((5)D(4)) and Fe((5)D(3)) products for the channel FeO-->Fe((5)D(4,3))+O((3)P) have been measured at several points in the 210-260 nm laser light wavelength region. The anisotropy parameter varies strongly with wavelength for both channels. PMID:15836034

Chestakov, D A; Parker, D H; Baklanov, A V

2005-02-22

149

Iron Intake in Relation to Diet and Iron Status of Young Adult Women  

Microsoft Academic Search

Aims: To determine the iron intake and food sources of iron in young adult women and to compare women with high versus low iron intake on diet and iron status. Methods: Iron intake and food sources were assessed by a 2-day estimated food record. Iron status was determined by a fasting venous blood sample. Differences in diet and iron status

I. Pynaert; J. Delanghe; M. Temmerman; S. De Henauw

2007-01-01

150

Free energies of mixing in the liquid iron-cobalt orthosilicates at 1450°c  

Microsoft Academic Search

Measurements have been made of the equilibrium between liquid iron-cobalt orthosilicates and solid iron-cobalt alloys. It\\u000a is shown that the integral free energies of mixing of the oxide components and the integral and partial molar free energies\\u000a of mixing of the pseudobinary (orthosilicate) components can be derived from a knowledge of the metallic activities in such\\u000a exchange equilibria. The thermodynamic

G. R. Belton; Hideaki Suito; D. R. Gaskell

1973-01-01

151

ASSESSMENT OF SURFACE RUNOFF FROM IRON AND STEEL MILLS  

EPA Science Inventory

The report gives results of a program to determine if surface runoff from iron and steel mills is an environmental problem. It includes a compilation of data available before this program, information gathered from plant tours, and results of a field survey at two fully integrate...

152

Combustion Iron Distribution and Deposition  

NASA Astrophysics Data System (ADS)

Iron is hypothesized to be an important micronutrient for ocean biota, thus modulating carbon dioxide uptake by the ocean biological pump. Studies have assumed that atmospheric deposition of iron to the open ocean is predominantly from mineral aerosols. For the first time, we model the source, transport and deposition of iron from combustion sources. Iron is produced in small quantities during fossil fuel burning, incinerator use, and biomass burning. The sources of combustion iron are concentrated in the industrialized regions and biomass burning regions, largely in the tropics. Model results suggest that combustion iron can represent up to 50 percent of the total iron deposited, but over open ocean regions is usually less than 5 percent of the total iron, with the highest values (less than 30 percent) close to the East Asian continent in the North Pacific. For ocean biogeochemistry the bioavailability of the iron is important, and this is often estimated by the fraction which is soluble (Fe(II)). Previous studies have argued that atmospheric processing of the relatively insoluble Fe(III) occurs to make it more soluble (Fe(II)). Modeled estimates of soluble iron amounts based solely on atmospheric processing as simulated here cannot match the variability in daily averaged in situ concentration measurements in Korea, which is located close to both combustion and dust sources. The best match to the observations is that there is substantial direct emissions of soluble iron from combustion processes. If we assume observed soluble Fe/black carbon (BC) ratios in Korea are representative of the whole globe, we obtain the result that deposition of soluble iron from combustion contribute 20-100 percent of the soluble iron deposition over many ocean regions. This implies that more work should be done refining the emissions and deposition of combustion sources of soluble iron globally.

Luo, C.; Mahowald, N.; Bond, T.; Chuang, P.; Artaxo, P.; Siefert, R.; Chen, Y.; Schauer, J.

2007-05-01

153

Preliminary evaluation of a conceptual molten iron gasification process for the production of hydrogen. [Molten iron gasification process  

Microsoft Academic Search

Conceptual designs for a molten iron hydrogen production process are developed and assessed, and process designs and costs are derived for the best of these designs. The selected designs have been integrated with the Solvent Refined Coal (SRC) plant presented in R and D Report No. 114, Interim Report No. 4 by The Ralph M. Parsons Company under Contract No.

L. Seglin; R. H. Lamb

1978-01-01

154

Iron homeostasis and eye disease  

PubMed Central

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,.

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

2009-01-01

155

Magnetic behavior of free-iron and iron oxide clusters  

NASA Astrophysics Data System (ADS)

We report the first measurement of the magnetic properties of isolated iron-atom clusters ranging in size from 2 to 17 atoms as well as the magnetic behavior of the monoxides and dioxides of (2-7)-atom iron clusters. Production of metal clusters is initiated by laser vaporization of an iron rod inside the throat of a high-pressure pulsed nozzle. The neutral metal cluster beam passes through a Stern-Gerlach magnet and the deflected beam is detected by spatially resolved time-of-flight photoionization mass spectrometry. From our analysis we conclude that the spin per atom of iron clusters is at least that of bulk iron, suggesting these small clusters are the precursors to bulk ferromagnetic iron.

Cox, D. M.; Trevor, D. J.; Whetten, R. L.; Rohlfing, E. A.; Kaldor, A.

1985-12-01

156

Iron oxide pillared graphite.  

PubMed

We show that alpha-Fe2O3- and Fe3O4-pillared graphites can be prepared by pillaring graphite oxide with trinuclear iron acetato complex ion and calcining it in air and in vacuo, respectively. A pillared graphite structure is confirmed by transmission electron microscopy observations. The adsorption isotherms of water indicate that the mesopores of Fe3O4-pillared graphite constitute a hydrophobic nanospace. PMID:15982031

Morishige, Kunimitsu; Hamada, Takanobu

2005-07-01

157

Is excess iron carcinogenic?  

Microsoft Academic Search

It is welt known that overnutrition, particularly with certain fatty acids, may be a co-factor in the carcinogenesis of e.g. breast and colon carcinoma. It is also well known that semi-starvation can delay the rate of growth of experimental tumors, and that so-called nutritional immunity can deprive tumor cells of nutrients like folates and iron, t Hyposideremia and hypofolatemia in

Peter Reizenstein

1990-01-01

158

Iron pages of HTSC  

SciTech Connect

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.

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

2010-08-15

159

Isotopic, petrologic and biogeochemical investigations of banded iron-formations  

NASA Technical Reports Server (NTRS)

It is recognized that the first occurrence of banded iron-formations (BIFs) clearly predates biological oxygenation of the atmosphere-hydrosphere system and that their last occurrences extend beyond plausible dates of pervasive biological oxygenation. For this reason, and because enormous quantities of oxidizing power have been sequestered in them, it is widely thought that these massive, but enigmatic, sediments must encode information about the mechanism and timing of the rise of atmospheric O2. By coupling isotopic analyses of iron-formation carbonates with biogeochemical and petrologic investigations, we are studying (1) the mechanism of initial sedimentation of iron; (2) the role of iron in microbially mediated diagenetic processes in fresh iron-formation sediments; and (3) the logical integration of mechanisms of deposition with observed levels of banding. Thus far, it has been shown that (1) carbonates in BIFs of the Hamersley Group of Western Australia are isotopically inhomogenous; (2) the nature and pattern of isotopic ordering is not consistent with a metamorphic origin for the overall depletion of C-13 observed in the carbonates; (3) if biological, the origin of the C-13 depleted carbonate could be either respiratory or fermentative; (4) iron may have been precipitate d as Fe(3+), then reduced to Fe(2+) within the sediment; and (5) sedimentary biogeochemical systems may have been at least partially closed to mass transport of carbonate species.

Hayes, J. M.; Kaufman, A. J.; Klein, C.; Studley, S. A.; Baur, M. E.; Walter, M. R.

1986-01-01

160

Flare Plasma Iron Abundance  

NASA Technical Reports Server (NTRS)

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.

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

2008-01-01

161

Extracellular Iron Biomineralization by Photoautotrophic Iron-Oxidizing Bacteria  

Microsoft Academic Search

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

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

2009-01-01

162

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

Microsoft Academic Search

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

ANATOLE BESARAB; WALTER HERMANN HÖRL

163

Biologically induced iron ore at Gunma iron mine, Japan  

Microsoft Academic Search

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

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

1999-01-01

164

Magnetic behavior of free-iron and iron oxide clusters  

Microsoft Academic Search

We report the first measurement of the magnetic properties of isolated iron-atom clusters ranging in size from 2 to 17 atoms as well as the magnetic behavior of the monoxides and dioxides of (2-7)-atom iron clusters. Production of metal clusters is initiated by laser vaporization of an iron rod inside the throat of a high-pressure pulsed nozzle. The neutral metal

D. M. Cox; D. J. Trevor; R. L. Whetten; E. A. Rohlfing; A. Kaldor

1985-01-01

165

Iron and ferritin accumulate in separate cellular locations in Phaseolus seeds  

PubMed Central

Background Iron is an important micronutrient for all living organisms. Almost 25% of the world population is affected by iron deficiency, a leading cause of anemia. In plants, iron deficiency leads to chlorosis and reduced yield. Both animals and plants may suffer from iron deficiency when their diet or environment lacks bioavailable iron. A sustainable way to reduce iron malnutrition in humans is to develop staple crops with increased content of bioavailable iron. Knowledge of where and how iron accumulates in seeds of crop plants will increase the understanding of plant iron metabolism and will assist in the production of staples with increased bioavailable iron. Results Here we reveal the distribution of iron in seeds of three Phaseolus species including thirteen genotypes of P. vulgaris, P. coccineus, and P. lunatus. We showed that high concentrations of iron accumulate in cells surrounding the provascular tissue of P. vulgaris and P. coccineus seeds. Using the Perls' Prussian blue method, we were able to detect iron in the cytoplasm of epidermal cells, cells near the epidermis, and cells surrounding the provascular tissue. In contrast, the protein ferritin that has been suggested as the major iron storage protein in legumes was only detected in the amyloplasts of the seed embryo. Using the non-destructive micro-PIXE (Particle Induced X-ray Emission) technique we show that the tissue in the proximity of the provascular bundles holds up to 500 ?g g-1 of iron, depending on the genotype. In contrast to P. vulgaris and P. coccineus, we did not observe iron accumulation in the cells surrounding the provascular tissues of P. lunatus cotyledons. A novel iron-rich genotype, NUA35, with a high concentration of iron both in the seed coat and cotyledons was bred from a cross between an Andean and a Mesoamerican genotype. Conclusions The presented results emphasize the importance of complementing research in model organisms with analysis in crop plants and they suggest that iron distribution criteria should be integrated into selection strategies for bean biofortification.

2010-01-01

166

Expanding horizons in iron chelation and the treatment of cancer: role of iron in the regulation of ER stress and the epithelial-mesenchymal transition.  

PubMed

Cancer is a major public health issue and, despite recent advances, effective clinical management remains elusive due to intra-tumoural heterogeneity and therapeutic resistance. Iron is a trace element integral to a multitude of metabolic processes, including DNA synthesis and energy transduction. Due to their generally heightened proliferative potential, cancer cells have a greater metabolic demand for iron than normal cells. As such, iron metabolism represents an important "Achilles' heel" for cancer that can be targeted by ligands that bind and sequester intracellular iron. Indeed, novel thiosemicarbazone chelators that act by a "double punch" mechanism to both bind intracellular iron and promote redox cycling reactions demonstrate marked potency and selectivity in vitro and in vivo against a range of tumours. The general mechanisms by which iron chelators selectively target tumour cells through the sequestration of intracellular iron fall into the following categories: (1) inhibition of cellular iron uptake/promotion of iron mobilisation; (2) inhibition of ribonucleotide reductase, the rate-limiting, iron-containing enzyme for DNA synthesis; (3) induction of cell cycle arrest; (4) promotion of localised and cytotoxic reactive oxygen species production by copper and iron complexes of thiosemicarbazones (e.g., Triapine(®) and Dp44mT); and (5) induction of metastasis and tumour suppressors (e.g., NDRG1 and p53, respectively). Emerging evidence indicates that chelators can further undermine the cancer phenotype via inhibiting the epithelial-mesenchymal transition that is critical for metastasis and by modulating ER stress. This review explores the "expanding horizons" for iron chelators in selectively targeting cancer cells. PMID:24472573

Lane, Darius J R; Mills, Thomas M; Shafie, Nurul H; Merlot, Angelica M; Saleh Moussa, Rayan; Kalinowski, Danuta S; Kovacevic, Zaklina; Richardson, Des R

2014-04-01

167

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

Code of Federal Regulations, 2010 CFR

...General graphitization. Each segment of cast iron or ductile iron pipe on which general graphitization is found to a degree...graphitization. Each segment of cast iron or ductile iron pipe on which localized graphitization is found to a...

2009-10-01

168

Intestinal Iron Homeostasis and Colon Tumorigenesis  

PubMed Central

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.

Xue, Xiang; Shah, Yatrik M.

2013-01-01

169

Iron, brain and restless legs syndrome  

Microsoft Academic Search

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

Jean Krieger; Carmen Schroeder

2001-01-01

170

Mössbauer Spectroscopy of Selected Banded Iron Formations  

Microsoft Academic Search

Banded iron formations are rocks of sedimentary origin, formed 2-4 billion years ago. They consist of alternating layers of iron oxides and silicates. In the oxide layers the iron is often in the Fe3+ state while in the silicate layers the iron is mainly in the Fe2+ state. The conditions under which banded iron formations formed are not understood, but

V W A Vieira; H G Jensen; J M Knudsen; M Olsen

1984-01-01

171

Chemistry and biology of eukaryotic iron metabolism  

Microsoft Academic Search

With rare exceptions, virtually all studied organisms from Archaea to man are dependent on iron for survival. Despite the ubiquitous distribution and abundance of iron in the biosphere, iron-dependent life must contend with the paradoxical hazards of iron deficiency and iron overload, each with its serious or fatal consequences. Homeostatic mechanisms regulating the absorption, transport, storage and mobilization of cellular

Philip Aisen; Caroline Enns; Marianne Wessling-Resnick

2001-01-01

172

Cellular management of iron in the brain  

Microsoft Academic Search

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

James R. Connor; Sharon L. Menzies

1995-01-01

173

Preventing childhood anemia in India: iron supplementation and beyond.  

PubMed

Childhood anemia has major adverse consequences for health and development. It's prevalence in India continues to range from 70 to 90%. Although anemia is multifactorial in etiology, preventative efforts have predominantly focused on increasing iron intake, primarily through supplementation in pregnant and lactating women. Policy thrust for childhood anemia is only recent. However, program implementation is dismal; only 3.8-4.7% of preschoolers receive iron-folate supplements. There is an urgent need for effective governance and implementation. Policy makers must distinguish anemia from iron deficiency, and introduce additional area-specific interventions as an integrated package.Increased iron intake may yield maximum benefit but will only address up to half the burden. In 6-59 months old children, instead of 100 days' continuous dosing with iron-folate syrup in a year, a directly supervised intermittent supplementation (biweekly; ~100 days per year) merits consideration. Multiple micronutrient powders for home fortification of foods in 6-23 months old infants do not appear viable. Additional interventions include delayed cord clamping, earlier supplementation in low birth weight infants, appropriate infant and young child feeding guidelines, and intermittent supervised supplementation in children and adolescents through school health programs. Use of double (iron-folate)-fortified salt in mid-day meal programs deserves piloting.Important area-specific, non-iron interventions include targeted deworming, and prevention and treatment of hemoglobinopathies, malaria and other common infections. Routine addition of multi-micronutrients to iron-folate supplementation appears unjustified currently. There is a pressing need to conduct relevant research, especially to inform etiology, additional interventions and implementation issues. PMID:23388662

Sachdev, H P S; Gera, T

2013-05-01

174

Pagophagia in iron deficiency anemia.  

PubMed

The relationship between pagophagia (ice pica) and iron deficiency anemia was studied. All 81 patients with iron deficiency anemia defined as hemoglobin <12.0 g/dl and ferritin level <12 ng/ml were interviewed about their habits of eating ice or other non-food substances. Pagophagia was defined as compulsive and repeated ingestion of at least one tray of ice or ice eating which was relieved after iron administration. Pagophagia was present in 13 patients (16.0%). All patients who received oral iron were periodically assessed employing a questionnaire on pagophagia and laboratory data. Iron therapy can cure the pagophagia earlier than hemoglobin recovery and repair of tissue iron deficiency. Although the pathogenesis of pagophagia is unclear, a biochemical approach involving the central nervous system might elucidate the mechanism underlying these abnormal behaviors. PMID:24850454

Uchida, Tatsumi; Kawati, Yasunori

2014-04-01

175

Microbial reduction of iron ore  

DOEpatents

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.

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

1989-01-01

176

The importance of bioavailability of dietary iron in relation to the expected effect from iron fortification  

Microsoft Academic Search

Background:The most common method of combating iron deficiency is iron fortification, especially in developing countries. However, few studies have shown a significant effect on iron status following iron fortification of low bioavailability diets.Objective:To investigate how iron fortification and dietary modifications affect iron absorption and rates of changes in iron stores.Methods:Research has made it possible to predict both iron absorption and

M Hoppe; L Hulthén; L Hallberg

2008-01-01

177

Iron Refractory Iron Deficiency Anemia: Presentation With Hyperferritinemia and Response to Oral Iron Therapy  

PubMed Central

Iron-refractory iron-deficiency anemia (IRIDA) is an autosomal recessive disorder caused by mutations in TMPRSS6. Patients have hypochromic microcytic anemia refractory to oral iron and are only partially responsive to parenteral iron administration. We report a French-Canadian kindred in which 2 siblings presented in early childhood with severe microcytic anemia, hypoferremia, and hyperferritinemia. Both children have been successfully treated solely with low-dose oral iron since diagnosis. Clinical and biological presentation did not fit any previously described genetic iron-deficiency anemia. Whole exome sequencing identified in both patients compound heterozygous mutations of TMPRSS6 leading to p.G442R and p.E522K, 2 mutations previously reported to cause classic IRIDA, and no additional mutations in known iron-regulatory genes. Thus, the phenotype associated with the unique combination of mutations uncovered in both patients expands the spectrum of disease associated with TMPRSS6 mutations to include iron deficiency anemia that is accompanied by hyperferritinemia at initial presentation and is responsive to continued oral iron therapy. Our results have implications for genetic testing in early childhood iron deficiency anemia. Importantly, they emphasize that whole exome sequencing can be used as a diagnostic tool and greatly facilitate the elucidation of the genetic basis of unusual clinical presentations, including hypomorphic mutations or compound heterozygosity leading to different phenotypes in known Mendelian diseases.

Khuong-Quang, Dong-Anh; Schwartzentruber, Jeremy; Westerman, Mark; Lepage, Pierre; Finberg, Karin E.; Majewski, Jacek

2013-01-01

178

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

PubMed Central

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.

Abhilashini, G.D.; Reddi, Rani

2014-01-01

179

Iron Aluminide Hot Gas Filters  

SciTech Connect

Currently, high temperature filter systems are in the demonstration phase with the first commercial scale hot filter systems being installed on integrated gasification combined cycle (IGCC) and pressurized fluid bed combustion cycle (PBFC) systems (70 MW). They are dependent on the development of durable and economic high temperature filter systems. These filters are mostly ceramic tubes or candles. Ceramic filter durability has not been high. Failure is usually attributed to mechanical or thermal shock: they can also undergo significant changes due to service conditions. The overall objective of this project is to commercialize weldable, crack resistant filters which will provide several years service in advanced power processes. The specific objectives of this project are to develop corrosion resistant alloys and manufacturing processes to make Iron Aluminide filter media, and to use a ``short term`` exposure apparatus supported by other tests to identify the most promising candidate (alloy plus sintering cycle). The objectives of the next phases are to demonstrate long term corrosion stability for the best candidate followed by the production of fifty filters (optional).

Hurley, J.; Brosious, S.; Johnson, M. [Pall Process Equipment Development Div., Pall Corp., Cortland, NY (United States)

1996-12-31

180

Enzymes of respiratory iron oxidation  

SciTech Connect

This report describes experimental progress in characterizing and identifying redox proteins in a number of iron-oxidizing bacteria. Sections of the paper are entitled (1) In Situ electrolysis was explored to achieve enhanced yields of iron-oxidizing bacteria, (2)Structure/function studies were performed on redox-active biomolecules from Thiobacillus ferrooxidans, (3) Novel redox-active biomolecules were demonstrated in other iron autotrophs, and (4) New probes of metalloprotein electron-transfer reactions were synthesized and characterized.

Blake, R. II.

1992-01-01

181

Ferromagnetic Gold-Iron Alloys  

Microsoft Academic Search

Magnetic measurements were made on a gold-iron alloy containing 37 atomic percent iron, both in the quenched and successively annealed states. It was found that the quenched supersaturated solid solution is ferromagnetic. When this supersaturated solid solution was gradually heated up, perceptible precipitation took place at about 450°C. Both the final gold-rich and iron-rich phases precipitated at 450°C were found

S. T. Pan; A. R. Kaufmann; F. Bitter

1942-01-01

182

Iron sulfide minerals in Black Sea sediments  

NASA Astrophysics Data System (ADS)

This study presents an integrated geochemical, environmental magnetic, and electron microscopic approach to better understand the physicochemical processes in deep sea sediments from the northwestern Black Sea. The investigated gravity core GC 214 was retrieved in 2007 during RV Meteor cruise M72/1 west of the Crimean Peninsula in a water depth of 1686 mbsf. Geochemical analyses of the pore water and solid phase indicate non-steady state sedimentation. The oxygen-depleted water column conditions, anaerobic oxidation of methane (AOM) and related microbially-driven sulfate reduction favor a highly complex iron sulfide mineral assemblage in the sediment column. The detailed magnetic susceptibility and remanence measurements indicate an irregularly stratified depth profile showing intervals of particularly high values. Further environmental magnetic analyses depict strongly elevated coercivities for those depth horizons, suggesting greigite as one of the main magnetic carrier minerals. Automated chemical classification (ACC), using electron dispersive spectrometer (EDS) attached to a JEOL840 scanning electron microscope (SEM), on dispersed particle samples permitted the identification of greigite (Fe3S4) next to pyrrhotite (Fe7S8), pyrite (FeS2) and monosulfides (FeS), but also allowed for the absolute quantification of the various mineral phases. These analyses were carried out on magnetic extracts and density separates to be able to calculate budgets between the different present iron sulfides. We obtained excellent correlations between the different iron sulfide concentrations and the magnetic signal. Additional analyses on polished sections yield inside into the details of the sulfidization pathways along the depth profile of the sediment sequence and help to develop a more general process model for this particular geochemical (paleo-)environment. Keywords: Black Sea, iron sulfides, environmental magnetism, anaerobic oxidation of methane (AOM), scanning electron microscopy (SEM), automated chemical classification (ACC), electron dispersive spectrometer (EDS)

Franke, C.; Robin, E.; Henkel, S.; Kasten, S.; Bleil, U.

2009-04-01

183

Snapshot of iron response in Shewanella oneidensis by gene network reconstruction  

SciTech Connect

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.

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

184

Iron dysregulation in Huntington's disease.  

PubMed

Huntington's disease (HD) is one of many neurodegenerative diseases with reported alterations in brain iron homeostasis that may contribute to neuropathogenesis. Iron accumulation in the specific brain areas of neurodegeneration in HD has been proposed based on observations in post-mortem tissue and magnetic resonance imaging studies. Altered magnetic resonance imaging signal within specific brain regions undergoing neurodegeneration has been consistently reported and interpreted as altered levels of brain iron. Biochemical studies using various techniques to measure iron species in human samples, mouse tissue, or in vitro has generated equivocal data to support such an association. Whether elevated brain iron occurs in HD, plays a significant contributing role in HD pathogenesis, or is a secondary effect remains currently unclear. Huntington's disease (HD) is one of many neurodegenerative diseases reported to have alterations in brain iron homeostasis. Whether elevated brain iron occurs in HD, and whether elevated iron levels play a significant contributory role in HD pathogenesis remains currently unclear. In this review, we discuss potential mechanisms by which mutant huntingtin-mediated increases in intracellular calcium and elevated intracellular iron may interact to result in elevated levels of reactive oxygen species leading to lipid peroxidation, DNA damage, and neuronal cell death. PMID:24717009

Muller, Michelle; Leavitt, Blair R

2014-08-01

185

Effects of iron deficiency on iron binding and internalization into acidic vacuoles in Dunaliella salina.  

PubMed

Uptake of iron in the halotolerant alga Dunaliella salina is mediated by a transferrin-like protein (TTf), which binds and internalizes Fe(3+) ions. Recently, we found that iron deficiency induces a large enhancement of iron binding, which is associated with accumulation of three other plasma membrane proteins that associate with TTf. In this study, we characterized the kinetic properties of iron binding and internalization and identified the site of iron internalization. Iron deficiency induces a 4-fold increase in Fe binding, but only 50% enhancement in the rate of iron uptake and also increases the affinity for iron and bicarbonate, a coligand for iron binding. These results indicate that iron deprivation leads to accumulation and modification of iron-binding sites. Iron uptake in iron-sufficient cells is preceded by an apparent time lag, resulting from prebound iron, which can be eliminated by unloading iron-binding sites. Iron is tightly bound to surface-exposed sites and hardly exchanges with medium iron. All bound iron is subsequently internalized. Accumulation of iron inhibits further iron binding and internalization. The vacuolar inhibitor bafilomycin inhibits iron uptake and internalization. Internalized iron was localized by electron microscopy within vacuolar structures that were identified as acidic vacuoles. Iron internalization is accompanied by endocytosis of surface proteins into these acidic vacuoles. A novel kinetic mechanism for iron uptake is proposed, which includes two pools of bound/compartmentalized iron separated by a rate-limiting internalization stage. The major parameter that is modulated by iron deficiency is the iron-binding capacity. We propose that excessive iron binding in iron-deficient cells serves as a temporary reservoir for iron that is subsequently internalized. This mechanism is particularly suitable for organisms that are exposed to large fluctuations in iron availability. PMID:17513481

Paz, Yakov; Shimoni, Eyal; Weiss, Meira; Pick, Uri

2007-07-01

186

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

PubMed

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

Cornelissen, C N; Sparling, P F

1994-12-01

187

Electrochemically fabricated zero-valent iron, iron-nickel, and iron-palladium nanowires for environmental remediation applications  

Microsoft Academic Search

Monodisperse crystalline zero-valent iron, iron-nickel, iron-palladium nanowires were synthesised using template-directed electrodeposition methods. Prior to nanowire fabrication, alumina nanotemplates with controlled pore structure (e.g. pore diameter and porosity) were fabricated by anodising high purity aluminium foil in sulphuric acid. After fabrication of alumina nanotemplates, iron, iron-nickel and iron- palladium nanowires were electrodeposited within the pore structure. The dimensions of nanowires

B.-Y. Yoo; S. C. Hernandez; B. Koo; Y. Rheem; N. V. Myung

2007-01-01

188

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

189

Nanosized Iron Oxide Colloids Strongly Enhance Microbial Iron Reduction? †  

PubMed Central

Microbial iron reduction is considered to be a significant subsurface process. The rate-limiting bioavailability of the insoluble iron oxyhydroxides, however, is a topic for debate. Surface area and mineral structure are recognized as crucial parameters for microbial reduction rates of bulk, macroaggregate iron minerals. However, a significant fraction of iron oxide minerals in the subsurface is supposed to be present as nanosized colloids. We therefore studied the role of colloidal iron oxides in microbial iron reduction. In batch growth experiments with Geobacter sulfurreducens, colloids of ferrihydrite (hydrodynamic diameter, 336 nm), hematite (123 nm), goethite (157 nm), and akaganeite (64 nm) were added as electron acceptors. The colloidal iron oxides were reduced up to 2 orders of magnitude more rapidly (up to 1,255 pmol h?1 cell?1) than bulk macroaggregates of the same iron phases (6 to 70 pmol h?1 cell?1). The increased reactivity was not only due to the large surface areas of the colloidal aggregates but also was due to a higher reactivity per unit surface. We hypothesize that this can be attributed to the high bioavailability of the nanosized aggregates and their colloidal suspension. Furthermore, a strong enhancement of reduction rates of bulk ferrihydrite was observed when nanosized ferrihydrite aggregates were added.

Bosch, Julian; Heister, Katja; Hofmann, Thilo; Meckenstock, Rainer U.

2010-01-01

190

Nanosized iron oxide colloids strongly enhance microbial iron reduction.  

PubMed

Microbial iron reduction is considered to be a significant subsurface process. The rate-limiting bioavailability of the insoluble iron oxyhydroxides, however, is a topic for debate. Surface area and mineral structure are recognized as crucial parameters for microbial reduction rates of bulk, macroaggregate iron minerals. However, a significant fraction of iron oxide minerals in the subsurface is supposed to be present as nanosized colloids. We therefore studied the role of colloidal iron oxides in microbial iron reduction. In batch growth experiments with Geobacter sulfurreducens, colloids of ferrihydrite (hydrodynamic diameter, 336 nm), hematite (123 nm), goethite (157 nm), and akaganeite (64 nm) were added as electron acceptors. The colloidal iron oxides were reduced up to 2 orders of magnitude more rapidly (up to 1,255 pmol h(-1) cell(-1)) than bulk macroaggregates of the same iron phases (6 to 70 pmol h(-1) cell(-1)). The increased reactivity was not only due to the large surface areas of the colloidal aggregates but also was due to a higher reactivity per unit surface. We hypothesize that this can be attributed to the high bioavailability of the nanosized aggregates and their colloidal suspension. Furthermore, a strong enhancement of reduction rates of bulk ferrihydrite was observed when nanosized ferrihydrite aggregates were added. PMID:19915036

Bosch, Julian; Heister, Katja; Hofmann, Thilo; Meckenstock, Rainer U

2010-01-01

191

IRON TEEMING FROM CUPOLA (UPPER RIGHT CORNER) DUCTILE IRON LADLE ...  

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

IRON TEEMING FROM CUPOLA (UPPER RIGHT CORNER) DUCTILE IRON LADLE MOVING DOWN TRACK IN PREPARATION FOR DISTRIBUTION TO DE LAVAUD MACHINES, LADLE TRANSFER CRANE ON FAR LEFT. - United States Pipe & Foundry Company Plant, Melting & Treatment Areas, 2023 St. Louis Avenue at I-20/59, Bessemer, Jefferson County, AL

192

IRON TEEMING FROM CUPOLA (UPPER RIGHT CORNER) DUCTILE IRON LADLE ...  

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

IRON TEEMING FROM CUPOLA (UPPER RIGHT CORNER) DUCTILE IRON LADLE MOVING DOWN TRACK IN PREPARATION FOR DISTRIBUTION TO DE LAVAUD MACHINES. - United States Pipe & Foundry Company Plant, Melting & Treatment Areas, 2023 St. Louis Avenue at I-20/59, Bessemer, Jefferson County, AL

193

Iron uptake and iron-repressible polypeptides in Yersinia pestis.  

PubMed Central

Pigmented (Pgm+) cells of Yersinia pestis are virulent, are sensitive to pesticin, adsorb exogenous hemin at 26 degrees C (Hms+), produce iron-repressible outer membrane proteins, and grow at 37 degrees C in iron-deficient media. These traits are lost upon spontaneous deletion of a chromosomal 102-kb pgm locus (Pgm-). Here we demonstrate that an Hms+ but pesticin-resistant (Pst(r)) mutant acquired a 5-bp deletion in the pesticin receptor gene (psn) encoding IrpB to IrpD. Growth and assimilation of iron by Pgm- and Hms+ Pst(r) mutants were markedly inhibited by ferrous chelators at 37 degrees C; inhibition by ferric and ferrous chelators was less effective at 26 degrees C. Iron-deficient growth at 26 degrees C induced iron-regulated outer membrane proteins of 34, 28.5, and 22.5 kDa and periplasmic polypeptides of 33.5 and 30 kDa. These findings provide a basis for understanding the psn-driven system of iron uptake, indicate the existence of at least one additional 26 degrees C-dependent iron assimilation system, and define over 30 iron-repressible proteins in Y. pestis.

Lucier, T S; Fetherston, J D; Brubaker, R R; Perry, R D

1996-01-01

194

Oxidation sizing of iron and iron-neodymium-boron powders  

Microsoft Academic Search

A powder sizing test developed for use on WC powders has been extended for use on iron and iron-neodymium-boron powders. In this test the particle size is derived from the rate of oxidation, because finer powders oxidize quicker. The rate of oxidation is monitored in a thermogravimetric analyser, where the powders are subjected to a controlled heating rate from room

M. Stewart; B. Roebuck; M. G. Gee

1991-01-01

195

Airway iron and iron-regulatory cytokines in cystic fibrosis  

Microsoft Academic Search

Iron availability is critical to Pseudomonas aeruginosa. The current authors determined sputum iron, ferritin, microalbumin levels and total cell counts (TCC) in 19 adult patients with cystic fibrosis (CF) during an acute exacerbation and repeated analyses following a median of 12 days antibiotic treatment. The current authors also determined sputum interleukin (IL)-1b and tumour necrosis factor (TNF)- a levels because

D. W. Reid; Q. T. Lam; H. Schneider; E. H. Walters

2004-01-01

196

The iron metallome in eukaryotic organisms.  

PubMed

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

Dlouhy, Adrienne C; Outten, Caryn E

2013-01-01

197

The Iron Metallome in Eukaryotic Organisms  

PubMed Central

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.

Dlouhy, Adrienne C.; Outten, Caryn E.

2013-01-01

198

THE SOLUBILITY OF LEAD IN LIQUID IRON  

Microsoft Academic Search

Measurements of the solubility of lead in liquid iron were made at 1550, ; 1600, 1650, and 1700 deg C using two different methods: liquid iron-liquid lead ; equilibration and liquid iron-lead vapor equilibration. (auth);

A. E. Lord; N. A. Parlee

1960-01-01

199

Can Iron Lift Your Learning Ability?  

ERIC Educational Resources Information Center

Presents samples of publicly available materials related to the role of iron in the diet. Summarizes what nutritionists feel about iron in the human diet and suggests some experiments related to iron for the classroom. (AIM)

Schibeci, Renato

1997-01-01

200

49 CFR 230.91 - Chafing irons.  

Code of Federal Regulations, 2013 CFR

... 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...

2013-10-01

201

Process for the Synthesis of Iron Powder.  

National Technical Information Service (NTIS)

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 fro...

1982-01-01

202

21 CFR 522.1182 - Iron injection.  

Code of Federal Regulations, 2010 CFR

...100 milligrams (mg) of elemental iron derived from: (i) Ferric hydroxide; (ii) Ferric oxide; or (iii) Elemental iron. (2) 200 mg of elemental iron derived from ferric hydroxide. (b) Sponsors and...

2010-04-01

203

Neoproterozoic banded iron formations  

Microsoft Academic Search

Two epochs of the formation of ferruginous quartzites—Archean-Paleoproterozoic (3.2–1.8 Ga) and Neoproterozoic (0.85–0.7 Ga)—are\\u000a distinguished in the Precambrian. They are incommensurable in scale: the Paleoproterozoic Kursk Group of the Kursk Magnetic\\u000a Anomaly (KMA) extends over 1500 km, whereas the extension of Neoproterozoic banded iron formations (BIF) beds does not exceed\\u000a a few tens of kilometers. Their thickness is up to

A. V. Ilyin

2009-01-01

204

Corrosion of Iron Experiment  

NSDL National Science Digital Library

The Materials Science and Technology Teacher's Workshop (MAST) provides this demonstration on corrosion. The laboratory exercise will allow students the opportunity to "observe the electrochemical nature of the changes in an iron nail when it corrodes and to investigate methods to protect it." Ways of preventing corrosion include protecting the metal with a more active metal and excluding oxygen and moisture from the material's surface with a protective coating. The lesson includes a step by step explanation of the laboratory procedure, discussion questions and teacher notes.

2011-11-14

205

Iron regulatory proteins in pathobiology.  

PubMed Central

The capacity of readily exchanging electrons makes iron not only essential for fundamental cell functions, but also a potential catalyst for chemical reactions involving free-radical formation and subsequent oxidative stress and cell damage. Cellular iron levels are therefore carefully regulated in order to maintain an adequate substrate while also minimizing the pool of potentially toxic 'free iron'. Iron homoeostasis is controlled through several genes, an increasing number of which have been found to contain non-coding sequences [i.e. the iron-responsive elements (IREs)] which are recognized at the mRNA level by two cytoplasmic iron-regulatory proteins (IRP-1 and IRP-2). The IRPs belong to the aconitase superfamily. By means of an Fe-S-cluster-dependent switch, IRP-1 can function as an mRNA-binding protein or as an enzyme that converts citrate into isocitrate. Although structurally and functionally similar to IRP-1, IRP-2 does not seem to assemble a cluster nor to possess aconitase activity; moreover, it has a distinct pattern of tissue expression and is modulated by means of proteasome-mediated degradation. In response to fluctuations in the level of the 'labile iron pool', IRPs act as key regulators of cellular iron homoeostasis as a result of the translational control of the expression of a number of iron metabolism-related genes. Conversely, various agents and conditions may affect IRP activity, thereby modulating iron and oxygen radical levels in different pathobiological settings. As the number of mRNAs regulated through IRE-IRP interactions keeps growing, the definition of IRPs as iron-regulatory proteins may in the near future become limiting as their role expands to other essential metabolic pathways.

Cairo, G; Pietrangelo, A

2000-01-01

206

Radiolabeled iron in soybeans: intrinsic labeling and bioavailability of iron to rats from defatted flour  

SciTech Connect

Soybeans can be efficiently labeled with radiolabeled iron by supplying the iron via a nutrient culture medium as an iron salt or as a chelate. By using dual labeled iron and EDTA, it was determined that none of the chelator was transported to the shoots with the iron. Therefore, the use of chelated iron as the iron source in the nutrient medium should not affect assessments of bioavailability of iron from plants. Bioavailability (determined from whole-body retention curves of /sup 59/Fe in rats) of iron from defatted soy flour was relatively high and addition of vitamin C did not significantly enhance absorption of iron from defatted soy flour.

Weaver, C.M.; Schmitt, H.A.; Stuart, M.A.; Mason, A.C.; Meyer, N.R.; Elliott, J.G.

1984-06-01

207

The Pharmacokinetics and Pharmacodynamics of Iron Preparations  

PubMed Central

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.

Geisser, Peter; Burckhardt, Susanna

2011-01-01

208

Plasma of iron powder combustion  

SciTech Connect

The results of experimental study of the thermal plasma formed in the two-phase diffusion flame of a burning iron dust cloud are presented. It has been demonstrated that the particles of iron oxide (magnetite) have sufficient charges to form ordered structures.

Doroshenko, J.; Florko, A.; Poletaev, N.; Vishnyakov, V. [Mechnikov Odessa National University, Odessa 65082 (Ukraine)

2007-09-15

209

Starch and Iron Absorption. (32431).  

National Technical Information Service (NTIS)

Decreased iron absorption was observed in rats fed protein deficient starch and sucrose diets. This was not caused by a direct intraluminal effect of starch or sucrose upon iron absorption. The abnormality was attributed to both a retarded rate of growth ...

F. D. Garretson M. E. Conrad

1967-01-01

210

Iron deficiency in the tropics.  

PubMed

Iron in food is classified as belonging to the haem pool, the nonhaem pool, and extraneous sources. Haem iron is derived from vegetable and animal sources with varying bioavailability. Hookworm infestation of the intestinal tract affects 450 million people in the tropics. Schistosoma mansoni caused blood loss in 7 Egyptian patients of 7.5- 25.9 ml/day which is equivalent to a daily loss of iron of .6-7.3 mg daily urinary loss of iron in 9 Egyptian patients. Trichuris trichiura infestation by whipworm is widespread in children with blood loss of 5 ml/day/worm. The etiology of anemia in children besides iron deficiency includes malaria, bacterial or viral infections, folate deficiency and sickle-cell disease. Severe infections cause profound iron-deficiency anemia in children in central American and Malaysia. Plasmodium falciparum malaria-induced anaemia in tropical Africa lowers the mean haemoglobin concentration in the population by 2 g/dI, causing profound anaemia in some. The increased risk of premature delivery, low birthweight, fetal abnormalities, and fetal death is directly related to the degree of maternal anemia. Perinatal mortality was reduced from 38 to 4% in treated anemic mothers. Mental performance was significantly lower in anemic school children and improved after they received iron. Supplements of iron, soy-protein, calcium, and vitamins given to villagers with widespread malnutrition, iron deficiency, and hookworm infestation in Colombia reduced enteric infections in children. Severe iron-deficiency anemia was treated in adults in northern Nigeria by daily in Ferastral 10 ml, which is equivalent to 500 mg of iron per day. Choloroquine, folic acid, rephenium hydroxynaphthoate, and tetrachlorethylene treat adults with severe iron deficiency from hookworm infestation in rural tropical Africa. Blood transfusion is indicated if the patient is dying of anaemia or is pregnant with a haemoglobin concentration 6 gm/dl. In South East Asia, mg per day prevented iron-deficiency anaemia in pregnancy. Field-trials on nutritional iron deficiency include an acidified milk formula plus ferrous sulphate for infants; biscuits with added bovine hemoglobin for children in Chile; sugar plus sodium ferric EDTA in Guatemala; salt with ferric orthophosphate and sodium acid sulphate in India; and Salt with ferrous sulphate plus sodium hexametaphosphate. PMID:7042157

Fleming, A F

1982-06-01

211

Magnetic resonance assessment of iron overload by separate measurement of tissue ferritin and hemosiderin iron  

PubMed Central

With transfusional iron overload, almost all the excess iron is sequestered intracellularly as rapidly mobilizable, dispersed, soluble, ferritin iron, and as aggregated, insoluble hemosiderin iron for long-term storage. Established magnetic resonance imaging (MRI) indicators of tissue iron (R2, R2*) are principally influenced by hemosiderin iron and change slowly, even with intensive iron chelation. Intracellular ferritin iron is evidently in equilibrium with the low-molecular-weight cytosolic iron pool that can change rapidly with iron chelation. We have developed a new magnetic resonance imaging (MRI) method to separately measure ferritin and hemosiderin iron, based on the non-monoexponential signal decay induced by aggregated iron in multiple-spin-echo sequences. We have initially validated the method in agarose phantoms and in human liver explants and shown the feasibility of its application in patients with thalassemia major. Measurement of tissue ferritin iron is a promising new means to rapidly evaluate the effectiveness of iron-chelating regimens.

Wu, Ed X.; Kim, Daniel; Tosti, Christina L.; Tang, Haiying; Jensen, Jens H.; Cheung, Jerry S.; Feng, Li; Au, Wing-Yan; Ha, Shau-Yin; Sheth, Sujit S.; Brown, Truman R.; Brittenham, Gary M.

2010-01-01

212

MRI measures of corpus callosum iron and myelin in early Huntington's disease.  

PubMed

Increased iron in subcortical gray matter (GM) structures of patients with Huntington's disease (HD) has been suggested as a causal factor in neuronal degeneration. But how iron content is related to white matter (WM) changes in HD is still unknown. For example, it is not clear whether WM changes share the same physiopathology (i.e. iron accumulation) with GM or whether there is a different mechanism. The present study used MRI to examine iron content in premanifest gene carriers (PreHD, n = 25) and in early HD patients (n = 25) compared with healthy controls (n = 50). 3T MRI acquisitions included high resolution 3D T1, EPI sequences for diffusion tensor imaging (DTI) as an indirect measure of tissue integrity, and T2*-weighted gradient echo-planar imaging for MR-based relaxometry (R2*), which provides an indirect measure of ferritin/iron deposition in the brain. Myelin breakdown starts in the PreHD stage, but there is no difference in iron content values. Iron content reduction manifests later, in the early HD stage, in which we found a lower R2* parameter value in the isthmus. The WM iron reduction in HD is temporally well-defined (no iron differences in PreHD subjects and iron differences only in early HD patients). Iron level in callosal WM may be regarded as a marker of disease state, as iron does not differentiate PreHD subjects from controls but distinguishes between PreHD and HD. Hum Brain Mapp 35:3143-3151, 2014. © 2013 Wiley Periodicals, Inc. PMID:24895252

Di Paola, M; Phillips, O R; Sanchez-Castaneda, C; Di Pardo, A; Maglione, V; Caltagirone, C; Sabatini, U; Squitieri, F

2014-07-01

213

Abnormal iron homeostasis and neurodegeneration  

PubMed Central

Abnormal iron metabolism is observed in many neurodegenerative diseases, however, only two have shown dysregulation of brain iron homeostasis as the primary cause of neurodegeneration. Herein, we review one of these - hereditary ferritinopathy (HF) or neuroferritinopathy, which is an autosomal dominant, adult onset degenerative disease caused by mutations in the ferritin light chain (FTL) gene. HF has a clinical phenotype characterized by a progressive movement disorder, behavioral disturbances, and cognitive impairment. The main pathologic findings are cystic cavitation of the basal ganglia, the presence of ferritin inclusion bodies (IBs), and substantial iron deposition. Mutant FTL subunits have altered sequence and length but assemble into soluble 24-mers that are ultrastructurally indistinguishable from those of the wild type. Crystallography shows substantial localized disruption of the normally tiny 4-fold pores between the ferritin subunits because of unraveling of the C-termini into multiple polypeptide conformations. This structural alteration causes attenuated net iron incorporation leading to cellular iron mishandling, ferritin aggregation, and oxidative damage at physiological concentrations of iron and ascorbate. A transgenic murine model parallels several features of HF, including a progressive neurological phenotype, ferritin IB formation, and misregulation of iron metabolism. These studies provide a working hypothesis for the pathogenesis of HF by implicating (1) a loss of normal ferritin function that triggers iron accumulation and overproduction of ferritin polypeptides, and (2) a gain of toxic function through radical production, ferritin aggregation, and oxidative stress. Importantly, the finding that ferritin aggregation can be reversed by iron chelators and oxidative damage can be inhibited by radical trapping may be used for clinical investigation. This work provides new insights into the role of abnormal iron metabolism in neurodegeneration.

Muhoberac, Barry B.; Vidal, Ruben

2013-01-01

214

Microbial acquisition of iron from ferric iron bearing minerals  

SciTech Connect

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.

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

1998-12-31

215

Safety of Iron Sucrose in Hemodialysis Patients Intolerant to Other Parenteral Iron Products  

Microsoft Academic Search

Background\\/Aims: This report summarizes the data gathered in four prospective studies of intravenous iron sucrose therapy administered to iron-deficient hemodialysis patients with a history of intolerance to other parenteral iron preparations. Methods: A total of 130 iron dextran- and\\/or sodium ferric gluconate-sensitive patients received intravenous iron sucrose therapy to correct iron deficiency, and\\/or maintain body iron stores. A history of

Chaim Charytan; Michael H. Schwenk; Mourhege M. Al-Saloum; Bruce S. Spinowitz

2004-01-01

216

Iron and Neurodegeneration in Multiple Sclerosis  

PubMed Central

Increased iron deposition might be implicated in multiple sclerosis (MS). Recent development of MRI enabled to determine brain iron levels in a quantitative manner, which has put more interest on studying the role of iron in MS. Evidence for abnormal iron homeostasis in MS comes also from analyses of iron and iron-related proteins in CSF and blood and postmortem MS brain sections. However, it is not yet clear if iron accumulation is implicated in MS pathology or merely reflects an epiphenomenon. Further interest has been generated by the idea of chronic cerebrospinal venous insufficiency that might be associated with brain iron accumulation due to a reduction in venous outflow, but its existence and etiologic role in MS are currently controversially debated. In future studies, combined approaches applying quantitative MRI together with CSF and serum analyses of iron and iron-related proteins in a clinical followup setting might help to elucidate the implication of iron accumulation in MS.

Khalil, Michael; Teunissen, Charlotte; Langkammer, Christian

2011-01-01

217

Unraveling Mechanisms Regulating Systemic Iron Homeostasis  

PubMed Central

Systemic iron balance must be tightly regulated to prevent the deleterious effects of iron deficiency and iron overload. Hepcidin, a circulating hormone that is synthesized by the liver, has emerged as a key regulator of systemic iron homeostasis. Hepcidin inhibits the absorption of dietary iron from the intestine as well as the release of iron derived from red blood cells from macrophages; thus, variation in hepcidin levels modifies the total amount of iron stored in the body as well as the availability of iron for erythropoiesis. The production of hepcidin by the liver is modulated by multiple physiological stimuli, including iron loading, inflammation, and erythropoietic activity. Investigation of the functions of the gene products mutated in inherited iron disorders using tissue culture systems and animal models has provided valuable insights into the mechanisms by which these hepcidin responses are mediated. This review focuses on recent advances in our understanding of the molecular mechanisms underlying the regulation of systemic iron homeostasis.

Finberg, Karin E.

2013-01-01

218

Intravenous Iron Versus Oral Iron in the Treatment of Postpartum Iron Deficiency Anemia  

Microsoft Academic Search

Background: Postpartum anemia can develop after delivery because of unforeseen medical problems during and after delivery which could complicate a mother’s ability to properly care for her newborn child. The current treatment for postpartum anemia is oral iron supplementation but this treatment has been associated with several gastrointestinal side effects. Alternative treatments include blood transfusions and intravenous (IV) iron therapy.

Meghan Crowley

2010-01-01

219

Silver-reductor method for determination of iron in iron ores and iron-ore sinters.  

PubMed

A new technique for the quick dissolution of iron ore, magnetite and sinter products has been developed. The sample is dissolved with thioglycollic acid and hydrochloric acid, the excess of thioglycollic acid is oxidized, and the iron is reduced in the silver reductor. PMID:18962704

Banerjee, S; Dutta, R K

1980-05-01

220

Iron biomineralization by anaerobic neutrophilic iron-oxidizing bacteria  

NASA Astrophysics Data System (ADS)

Minerals formed by bio-oxidation of ferrous iron (Fe(II)) at neutral pH, their association with bacterial ultrastructures as well as their impact on the metabolism of iron-oxidizing bacteria remain poorly understood. Here, we investigated iron biomineralization by the anaerobic nitrate-dependent iron-oxidizing bacterium Acidovorax sp. strain BoFeN1 in the presence of dissolved Fe(II) using electron microscopy and Scanning Transmission X-ray Microscopy (STXM). All detected minerals consisted mainly of amorphous iron phosphates, but based on their morphology and localization, three types of precipitates could be discriminated: (1) mineralized filaments at distance from the cells, (2) globules of 100 ± 25 nm in diameter, at the cell surface and (3) a 40-nm thick mineralized layer within the periplasm. All of those phases were shown to be intimately associated with organic molecules. Periplasmic encrustation was accompanied by an accumulation of protein moieties. In the same way, exopolysaccharides were associated with the extracellular mineralized filaments. The evolution of cell encrustation was followed by TEM over the time course of a culture: cell encrustation proceeded progressively, with rapid precipitation in the periplasm (in a few tens of minutes), followed by the formation of surface-bound globules. Moreover, we frequently observed an asymmetric mineral thickening at the cell poles. In parallel, the evolution of iron oxidation was quantified by STXM: iron both contained in the bacteria and in the extracellular precipitates reached complete oxidation within 6 days. While a progressive oxidation of Fe in the bacteria and in the medium could be observed, spatial redox (oxido-reduction state) heterogeneities were detected at the cell poles and in the extracellular precipitates after 1 day. All these findings provide new information to further the understanding of molecular processes involved in iron biomineralization by anaerobic iron-oxidizing bacteria and offer potential signatures of those metabolisms that can be looked for in the geological record.

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

2009-02-01

221

Integrated Means Integrity  

ERIC Educational Resources Information Center

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)

Odegard, John D.

1978-01-01

222

Reduction of Soluble Iron and Reductive Dissolution of Ferric Iron-Containing Minerals by Moderately Thermophilic Iron-Oxidizing Bacteria  

Microsoft Academic Search

Five moderately thermophilic iron-oxidizing bacteria, including representative strains of the three classified species (Sulfobacillus thermosulfidooxidans, Sulfobacillus acidophilus, and Acidimicrobium ferrooxidans), were shown to be capable of reducing ferric iron to ferrous iron when they were grown under oxygen limitation conditions. Iron reduction was most readily observed when the isolates were grown as mixotrophs or hetero- trophs with glycerol as an

TONI A. M. BRIDGE; D. BARRIE JOHNSON

1998-01-01

223

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.

224

Antimony in iron meteorites  

NASA Technical Reports Server (NTRS)

Sb concentrations determined by radiochemical neutron activation analysis in 60 iron meteorites range from 0.2 ng/g to 36 microg/g. The meteorites with the highest Sb concentrations are those of the nonmagmatic groups IAB and IIICD, while meteorites with the lowest Sb concentrations are found in groups IVA and IVB. In all groups Sb is positively correlated with Ni; slopes on log Sb vs log Ni plots decrease with increasing Ni. This decrease may reflect an increasing tendency to avoid schreibersite during the analysis of high-Ni meteorites because Sb partitions strongly into schreibersite. It is found that schreibersite from New Westville is enriched in Cr, Ni, Ge, As, Sb, and Au and depleted in Fe, Co, Ir; the Sb content in schreibersite is 540 times higher than the bulk metal value.

Willis, J.

1981-01-01

225

Iron Mountain Electromagnetic Results  

SciTech Connect

Iron Mountain Mine is located seventeen miles northwest of Redding, CA. After the completion of mining in early 1960s, the mine workings have been exposed to environmental elements which have resulted in degradation in water quality in the surrounding water sheds. In 1985, the EPA plugged ore stoops in many of the accessible mine drifts in an attempt to restrict water flow through the mine workings. During this process little data was gathered on the orientation of the stoops and construction of the plugs. During the last 25 years, plugs have begun to deteriorate and allow acidic waters from the upper workings to flow out of the mine. A team from Idaho National Laboratory (INL) performed geophysical surveys on a single mine drift and 3 concrete plugs. The project goal was to evaluate several geophysical methods to determine competence of the concrete plugs and orientation of the stopes.

Gail Heath

2012-07-01

226

Comparison of polysaccharide iron complexes used as iron supplements.  

PubMed

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

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

1995-03-01

227

Recovery of scrap iron metal value using biogenerated ferric iron.  

PubMed

The utility of employing biogenerated ferric iron as an oxidant for the recycling of scrap metal has been demonstrated using continuously growing cells of the extremophilic organism Acidithiobacillus ferrooxidans. A ferric iron rich (70 mol%) lixiviant resulting from bioreactor based growth of A. ferrooxidans readily solubilized target scrap metal with the resultant generation of a leachate containing elevated ferrous iron levels and solubilized copper previously resident in the scrap metal. Recovery of the copper value was easily accomplished via a cementation reaction and the clarified leachate containing a replenished level of ferrous iron as growth substrate was shown to support the growth of A. ferrooxidans and be fully recyclable. The described process for scrap metal recycling and copper recovery was shown to be efficient and economically attractive. Additionally, the utility of employing the E(h) of the growth medium as a means for monitoring fluctuations in cell density in cultures of A. ferrooxidans is demonstrated. PMID:16440341

Ballor, Nicholas R; Nesbitt, Carl C; Lueking, Donald R

2006-04-20

228

Gaseous reduction of iron oxides: Part III. Reduction-oxidation of porous and dense iron oxides and iron  

Microsoft Academic Search

The internal reduction of high-grade granular hematite ore in hydrogen and carbon monoxide, and also the internal oxidation\\u000a of porous iron granules in CO2-CO mixtures have been investigated. To assist the interpretation of the rate data for porous iron and iron oxides, rate measurements\\u000a have been made also with dense wustite, previously grown on iron by oxidation. The iron formed

E. T. Turkdogan; J. V. Vinters

1972-01-01

229

Iron status of breastfed infants is improved equally by medicinal iron and iron-fortified cereal123  

PubMed Central

Background: Although uncommon, iron deficiency (ID) occurs in breastfed infants. The regular provision of iron may prevent ID. Objective: The objective was to test the feasibility and effectiveness of 2 modalities of providing iron (medicinal iron or iron-fortified cereal) to breastfed infants. The study tested the hypothesis that regular provision of iron improves iron status of breastfed infants without adverse effects. Design: In this prospective, randomized, open-label trial, breastfed infants received on a regular basis either medicinal iron (n = 48) or an iron-fortified fruit-cereal combination (n = 45) from 4 to 9 mo or no intervention (control group; n = 59). The interventions provided 7.0–7.5 mg ferrous sulfate/d. Infants were enrolled at 1 mo and were followed to 2 y. Iron-status indicators were determined periodically, stool characteristics were recorded, and growth was monitored. Results: The regular provision of iron led to improved iron status during and for some months after the intervention. Both sources of iron were about equally effective. Iron affected stool color but had no effect on feeding-related behavior. However, medicinal iron was associated with a small but significant reduction in length gain and a trend toward reduced weight gain. ID anemia was observed in 4 infants (2.3%), most of whom had a low birth iron endowment. Mild ID was common in the second year of life. Conclusions: Regular provision of medicinal iron or iron-fortified cereal improves the iron status of breastfed infants and may prevent ID. Both modalities are equally effective, but medicinal iron leads to somewhat reduced growth. This trial was registered at clinicaltrials.gov as NCT00760890.

Nelson, Steven E; Jeter, Janice M

2009-01-01

230

21 CFR 186.1374 - Iron oxides.  

Code of Federal Regulations, 2013 CFR

(a) Iron oxides (oxides of iron, CAS Reg. No. 1332-37-2) are undefined mixtures of iron (II) oxide (CAS Reg. No. 1345-25-1, black cubic crystals) and iron (III) oxide (CAS Reg. No. 1309-37-1, red-brown to black trigonal crystals). (b) In accordance with §...

2013-04-01

231

Hepcidin, A New Iron Regulatory Peptide  

Microsoft Academic Search

ABSTRACTMaintaining normal iron homeostasis is essential for the organism, as both iron deficiency and iron excess are associated with cellular dysfunction. Recently, several lines of evidence have suggested that hepcidin, a peptide mainly produced by the liver, plays a major role in the control of body iron homeostasis. The subject of this paper is to summarize the advances toward the

Gaël Nicolas; Lydie Viatte; Myriam Bennoun; Carole Beaumont; Axel Kahn; Sophie Vaulont

2002-01-01

232

46 CFR 56.60-10 - Cast iron and malleable iron.  

Code of Federal Regulations, 2010 CFR

...occur should be avoided. Cast iron and malleable iron...temperatures above 450 °F. Cast iron and malleable...a) may be used at pressures not exceeding the...Malleable iron and cast iron valves and fittings...service provided the pressure limitation of 300...

2009-10-01

233

46 CFR 56.60-10 - Cast iron and malleable iron.  

Code of Federal Regulations, 2013 CFR

...occur should be avoided. Cast iron and malleable iron...temperatures above 450 °F. Cast iron and malleable...a) may be used at pressures not exceeding the...Malleable iron and cast iron valves and fittings...service provided the pressure limitation of 300...

2013-10-01

234

46 CFR 56.60-10 - Cast iron and malleable iron.  

Code of Federal Regulations, 2010 CFR

...occur should be avoided. Cast iron and malleable iron...temperatures above 450 °F. Cast iron and malleable...a) may be used at pressures not exceeding the...Malleable iron and cast iron valves and fittings...service provided the pressure limitation of 300...

2010-10-01

235

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

Code of Federal Regulations, 2010 CFR

...Cast iron and ductile iron. (a) Cast or ductile iron pipe less than 6 inches (152 millimeters) in diameter...installed for service lines. (b) If cast iron pipe or ductile iron pipe is installed for use as a service line,...

2009-10-01

236

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

Code of Federal Regulations, 2010 CFR

...Cast iron and ductile iron. (a) Cast or ductile iron pipe less than 6 inches (152 millimeters) in diameter...installed for service lines. (b) If cast iron pipe or ductile iron pipe is installed for use as a service line,...

2010-10-01

237

Uptake and metabolism of iron and iron oxide nanoparticles in brain astrocytes.  

PubMed

Astrocytes are considered key regulators of the iron metabolism of the brain. These cells are able to rapidly accumulate iron ions and various iron-containing compounds, store iron efficiently in ferritin and also export iron. The present short review summarizes our current knowledge of the molecular mechanisms involved in the handling of iron by astrocytes. Cultured astrocytes efficiently take up iron as ferrous or ferric iron ions or as haem by specific iron transport proteins in their cell membrane. In addition, astrocytes accumulate large amounts of iron oxide nanoparticles by endocytotic mechanisms. Despite the rapid accumulation of high amounts of iron from various iron-containing sources, the viability of astrocytes is hardly affected. A rather slow liberation of iron from accumulated haem or iron oxide nanoparticles as well as the strong up-regulation of the synthesis of the iron storage protein ferritin are likely to contribute to the high resistance of astrocytes to iron toxicity. The efficient uptake of extracellular iron by cultured astrocytes as well as their strong up-regulation of ferritin after iron exposure also suggests that brain astrocytes deal well with an excess of iron and protect the brain against iron-mediated toxicity. PMID:24256259

Hohnholt, Michaela C; Dringen, Ralf

2013-12-01

238

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

Code of Federal Regulations, 2013 CFR

...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...

2013-10-01

239

Microorganisms pumping iron: anaerobic microbial iron oxidation and reduction  

Microsoft Academic Search

Iron (Fe) has long been a recognized physiological requirement for life, yet for many microorganisms that persist in water, soils and sediments, its role extends well beyond that of a nutritional necessity. Fe(II) can function as an electron source for iron-oxidizing microorganisms under both oxic and anoxic conditions and Fe(III) can function as a terminal electron acceptor under anoxic conditions

Karrie A. Weber; Laurie A. Achenbach; John D. Coates

2006-01-01

240

Mechanism of thermochemical growth of iron borides on iron  

Microsoft Academic Search

The mechanism of thermochemical growth of iron borides on iron was studied by analysing the products which form on samples placed in contact with B4C-base powder mixtures with different boronising potential. The analyses were carried out by means of metallographic and X-ray diffraction techniques. Three subsequent stages of growth were observed which explain the occurrence of typical properties of the

C. Martini; G. Palombarini; M. Carbucicchio

2004-01-01

241

Deep-seated iron ores from banded-iron formation  

Microsoft Academic Search

Very large iron ore deposits have formed in many parts of the world, evidently by the supergene alteration of Precambrian banded-iron formation (BIF). Some of these deposits extend to great depths, ranging to 2,400 m at Krivoyrog1, beyond the likely reach of oxygenated water. We propose here, on the basis of studies in the Hamersley Ranges, Western Australia, a mechanism

R. C. Morris; M. R. Thornber; W. E. Ewers

1980-01-01

242

Isotopic variations of germanium in iron and stony iron meteorites  

Microsoft Academic Search

Germanium isotopic ratios for six iron meteorites of various groups, metallic phase of pallasite stony iron meteorites, three chemical reagents, and terrestrial germanite sample from Tsumeb mine, Namibia have been determined using a multiple collector-inductively coupled plasma mass spectrometer (MC-ICPMS). In this study, Ga-external correction technique, which enables us to detect the isotopic fractionation of the elements during the sample

Takefumi Hirata

1997-01-01

243

Iron deficiency anemia in heart failure.  

PubMed

Anemia and iron deficiency are quite prevalent in patients with heart failure (HF) and may overlap. Both anemia and iron deficiency are associated with worse symptoms and adverse clinical outcomes. In the past few years, there has been an enormous interest in the subject of iron deficiency and its management in patients with HF. In this review, the etiology and relevance of iron deficiency, iron metabolism in the setting of HF, studies on iron supplementation in patients with HF and potential cardiovascular effects of subclinical iron overload are discussed. PMID:22948485

Arora, Natasha P; Ghali, Jalal K

2013-07-01

244

Extracellular Iron Biomineralization by Photoautotrophic Iron-Oxidizing Bacteria ? †  

PubMed Central

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.

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

2009-01-01

245

Field theory CAD of waffle-iron filters  

Microsoft Academic Search

A combined generalized scattering matrix\\/Galerkin's method for CAD of waveguide waffle-iron filters is presented. The proposed technique includes the solution of eigenvalue problems for multiridged waveguide sections, the solution of key scattering problems for basic discontinuities and evaluation of total S-matrix of filter. All particular eigenvalue problems and scattering problems are reduced to corresponding systems of electric field integral equations

Mikhail B. Manuilov; Konstantin V. Kobrin

2005-01-01

246

Cooperative strategies in iron and steel: Motives and results  

Microsoft Academic Search

During the past quarter-century, the American iron and steel industry has undergone far-reaching structural changes. Until the mid-1980s the established, integrated producers responded to these changes with essentially defensive measures. Then they began to embark on a radically new strategy--the establishment of joint ventures with foreign, especially Japanese, competitors. So far, these ventures have been concentrated in the production of

G Rosegger

1992-01-01

247

Process for the synthesis of iron powder  

DOEpatents

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.

Welbon, W.W.

1983-11-08

248

Magnetic Resonance Imaging Quantification of Liver Iron  

PubMed Central

Iron overload is the histological hallmark of genetic hemochromatosis and transfusional hemosiderosis but also may occur in chronic hepatopathies. This article provides an overview of iron deposition and diseases where liver iron overload is clinically relevant. Next, this article reviews why quantitative non-invasive biomarkers of liver iron would be beneficial. Finally, we describe current state of the art methods for quantifying iron with MRI and review remaining challenges and unsolved problems,

Sirlin, Claude B.; Reeder, Scott B.

2011-01-01

249

Iron and Women’s Health  

Microsoft Academic Search

\\u000a • Iron is an essential mineral required for transport of oxygen throughout the body and for the optimal development of the\\u000a fetal brain.\\u000a \\u000a \\u000a • Iron-intake requirements are regulated by the size of body iron stores. Lifestyle factors that often influence iron status\\u000a in women include amount of iron consumed, use of oral contraceptives, use of hormone replacement therapy, vegetarianism, intestinal

Adrianne Bendich; Ronit Zilberboim

250

Oxygen isotope relationships in iron meteorites  

NASA Technical Reports Server (NTRS)

Iron meteorites with oxygen-bearing phases can be classified in terms of their oxygen isotopic abundances. These iron meteorite classes are isotopically similar to various stony meteorite classes, which may indicate a common origin. The group IAB and IIICD irons may be related to the winonaites; group IIE irons may be related to H chondrites; group IVA irons may be related to L or LL chondrites.

Clayton, R. N.; Mayeda, T. K.; Olsen, E. J.; Prinz, M.

1983-01-01

251

Luminescent iron clusters in solution.  

PubMed

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 [Fe??(TOPO)?(H?O)?](+), [Fe??(TOPO)?(H?O)](+) and [Fe?(TOPO)(H?O)?](+) by mass spectrometry. This study lays the groundwork for exploiting unique properties of soluble iron clusters. PMID:24356936

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

2014-01-16

252

Iron for restless legs syndrome  

PubMed Central

Background Restless legs syndrome (RLS) is a common neurologic syndrome and is associated with iron deficiency in many patients. It is unclear whether iron therapy is effective treatment for RLS. Objectives The objective of this review was to assess the effects of iron supplementation (oral or intravenous) for patients with RLS. Search methods We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (Jan 1995 to April 2011); EMBASE (Jan 1995 to April 2011); PsycINFO (Jan 1995 to April 2011); and CINAHL (Jan 1995 to April 2011). Corresponding authors of included trials and additional members of the International Restless Legs Syndrome Study Group were contacted to locate additional published or unpublished trials. Selection criteria Controlled trials comparing any formulation of iron with placebo, other medications, or no treatment in adults diagnosed with RLS according to expert clinical interview or explicit diagnostic criteria. Data collection and analysis Two review authors extracted data and at least two authors assessed trial quality. We contacted trial authors for missing data. Main results Six studies (192 total subjects) were identified and included in this analysis. The quality of trials was variable. Our primary outcome was restlessness or uncomfortable leg sensations, which was quantified using the IRLS severity scale in four trials and another RLS symptom scale in a fifth trial. Combining data from the four trials using the IRLS severity scale, there was no clear benefit from iron therapy (mean difference in IRLS severity scores of -3.79, 95% CI: -7.68 to 0.10, p = 0.06). However, the fifth trial did find iron therapy to be beneficial (median decrease of 3 points in the iron group and no change in the placebo group on a 10 point scale of RLS symptoms, p = 0.01). Quality of life was improved in the iron group relative to placebo in some studies but not others. Changes in periodic limb movements were not different between groups (measured in two studies). Objective sleep quality, subjective sleep quality and daytime functioning were not different between treatment groups in the studies that assessed them. The single study of subjects with end stage renal disease did show a benefit of therapy. Most trials did not require subjects to have co-morbid iron deficiency and several excluded patients with severe anemia. The single study that was limited to iron deficient subjects did not show clear benefit of iron supplementation on RLS symptoms. There was no clear superiority of oral or intravenous delivery of iron. Iron therapy did not result in significantly more side effects than placebo (RR 1.39, 95% CI 0.85 to 2.27). Authors' conclusions There is insufficient evidence to determine whether iron therapy is beneficial for the treatment of RLS. Further research to determine whether some or all types of RLS patients may benefit from iron therapy, as well as the best route of iron administration, is needed.

Trotti, Lynn M; Bhadriraju, Srinivas; Becker, Lorne A

2014-01-01

253

Iron Radiation in Tokamak Discharges.  

National Technical Information Service (NTIS)

Iron ion resonance-line intensity measurements are described as a representative sample of spectroscopic diagnostics of tokamak plasmas. A brief outline of the tokamak discharge characteristics is followed by a description of the spectrometer, and its cal...

E. Hinnov

1978-01-01

254

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

PubMed Central

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.

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

2012-01-01

255

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

NASA Astrophysics Data System (ADS)

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.

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

2012-12-01

256

Ironing out the phosphorus problem  

Microsoft Academic Search

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

Joshua J Zaritsky; Isidro B Salusky

2010-01-01

257

Nitrate reduction by metallic iron  

Microsoft Academic Search

Chemical reduction of nitrate by metallic iron (Fe0) was studied as a potential technology to remove nitrate from water. The effects of pH and the iron-to-nitrate ratio on both nitrate reduction rate and percent removal were investigated. Rate constants and the apparent reaction order with respect to nitrate were determined and a mass balance was obtained. Rapid nitrate reduction by

Chin-Pao Huang; Hung-Wen Wang; Pei-Chun Chiu

1998-01-01

258

Properties of iron silicide nanowires  

Microsoft Academic Search

Iron silicide nanowires (NWs) were grown and studied in this work. We have found that self-assembled epitaxial iron silicide NWs grown on Si(110) can be converted from a cubic s-phase to an orthorhombic beta-phase FeSi 2 by annealing at 800°C for 1 hour. The transformation temperature of 800°C is considerably higher than that observed in thin films (200-500°C), due to

Shengde Liang

2006-01-01

259

Mucosal iron in the control of iron absorption in a rat intestinal transplant model  

SciTech Connect

Isogeneic intestinal transplantation of iron-loaded and iron-deficient intestine into iron-deficient rats was performed in 20 Lewis rats to isolate the effect of intestinal mucosal iron on iron absorption. Rats were iron loaded with three weekly IM injections of 50 mg of iron dextran and were rendered iron deficient with an iron-deficient diet for 3 weeks. Iron status was assessed by hepatic and gut mucosal iron determination. Uptake and transfer of 59Fe-ascorbate was measured in an isolated perfused segment of transplanted intestine 48 hours after transplantation. The mean rate of uptake of 59Fe from an iron-loaded intestine (mean mucosal iron concentration, 7.97 +/- 2.02 mumol/g) was 431 +/- 27 nmol/30 min, and from an iron-deficient intestine (mean mucosal iron concentration, 1.35 +/- .84 mumol/g), 743 +/- 222 nmol/30 min (P less than 0.001). The mean transfer of 59Fe from the mucosal cell to the body through an iron-loaded intestine was 63 +/- 22 nmol/30 min, and through an iron-deficient intestine was 86 +/- 32 nmol/30 min (P less than 0.05). These results suggest that the gut mucosal iron concentration regulates the uptake and transfer of iron in the intestine.

Adams, P.C.; Zhong, R.; Haist, J.; Flanagan, P.R.; Grant, D.R. (Univ. of Western Ontario, London (Canada))

1991-02-01

260

Rethinking Iron Regulation and Assessment in Iron Deficiency, Anemia of Chronic Disease, and Obesity: Introducing Hepcidin  

PubMed Central

Adequate iron availability is essential to human development and overall health. Iron is a key component of oxygen-carrying proteins, has a pivotal role in cellular metabolism, and is essential to cell growth and differentiation. Inadequate dietary iron intake, chronic and acute inflammatory conditions, and obesity are each associated with alterations in iron homeostasis. Tight regulation of iron is necessary because iron is highly toxic and human beings can only excrete small amounts through sweat, skin and enterocyte sloughing, and fecal and menstrual blood loss. Hepcidin, a small peptide hormone produced mainly by the liver, acts as the key regulator of systemic iron homeostasis. Hepcidin controls movement of iron into plasma by regulating the activity of the sole known iron exporter ferroportin-1. Downregulation of the ferroportin-1 exporter results in sequestration of iron within intestinal enterocytes, hepatocytes, and iron-storing macrophages reducing iron bioavailability. Hepcidin expression is increased by higher body iron levels and inflammation and decreased by anemia and hypoxia. Importantly, existing data illustrate that hepcidin may play a significant role in the development of several iron-related disorders, including the anemia of chronic disease and the iron dysregulation observed in obesity. Therefore, the purpose of this article is to discuss iron regulation, with specific emphasis on systemic regulation by hepcidin, and examine the role of hepcidin within several disease states, including iron deficiency, anemia of chronic disease, and obesity. The relationship between obesity and iron depletion and the clinical assessment of iron status will also be reviewed.

Tussing-Humphreys, Lisa; Pustacioglu, Cenk; Nemeth, Elizabeta; Braunschweig, Carol

2012-01-01

261

Eccentricity Dependence on Iron Abundance  

NASA Astrophysics Data System (ADS)

The occurrence and eccentricity distribution of planets as a function of period is significantly different for iron-rich and iron-poor planet systems. We find that iron-poor stars with planets having periods between 525 and 600 days have higher eccentricity than such systems outside this range. If whole planet pollution causes the correlation of giant planet eccentricity with stellar iron abundance, then this cluster could be due to a paucity of pollution in this period range. Newly reported patterns of planet occurrence must result from planet system architectural features such as the snow line, followed by subsequent migration. Different results favor pollution or higher initial iron abundance causing the higher occurrence fraction of giant planets hosted by iron-rich stars, but the two explanations could be complementary. Relations between planet and stellar parameters are a major product of planet-finding, which promise further insights into star-planet system formation and evolution. Collaborators are sought to study these patterns. We expect a spirited debate over the relative contributions of initial abundances, disk accretion, and whole planet accretion.

Taylor, Stuart F.

2014-01-01

262

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

National Technical Information Service (NTIS)

We are investigating biological mechanisms of terrestrial iron deposition as analogs for Martian hematite. Possible terrestrial analogs include iron oxide hydrothermal deposits, rock varnish, iron-rich laterites, ferricrete soils, moki balls, and banded i...

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

2005-01-01

263

Root Excretions in Iron-Deficient Tobacco Plants and Possible Effects on Iron Nutrition.  

National Technical Information Service (NTIS)

Tobacco plants grown without iron tended to excrete riboflavin to the external solution and to reabsorb it. The riboflavin translocation was somehow related to iron translocation in plants. Iron-deficient plants generally absorbed much more exp 59 Fe from...

A. Wallace E. F. Frolich A. ElGazzar

1967-01-01

264

The World Beyond Iron  

NASA Astrophysics Data System (ADS)

The mere fact that the Mössbauer effect was discovered with the 129.4 keV transition in 191Ir demonstrates immediately the availability of Mössbauer isotopes other than 57Fe. Nevertheless, the 57Fe resonance remains the soul of Mössbauer spectroscopy. It combines a number of favorable properties: a source with convenient half-life (270 days), a large recoil-free fraction which allows measurements well above room temperature, and an energy resolution of ˜ 10 - 8 eV which is one to two orders of magnitude smaller than the typical hyperfine interaction energies. Yet, the energy resolution is not high enough to lead to substantial line broadenings by the unavoidable small distortions in the crystalline lattice of a real solid. The low natural abundance (2,2%) of the 57Fe is compensated by the large resonance cross-section and isotopic enrichment is only needed for materials containing iron in very low concentration or for extremely small samples. 57Fe was in fact not the second Mössbauer transition to be used after 191Ir. In establishing the correctness of the, not immediately believed, result of Mössbauer, the group at Argonne National Laboratory [1] measured not only the recoil-free resonance absorption in 191Ir, but also that of the 100 keV transition in 182W. This historically number two resonance has later mainly be used for the establishment of nuclear parameters.

Kalvius, G. Michael

265

Potential low-grade iron ore deposits in metamorphosed banded iron formations, Northern Province, South Africa  

Microsoft Academic Search

Exploitation of low-grade iron ore would be quite unique in a South African context as South Africa is well endowed with\\u000a high-grade iron ore resources. Low-grade iron ore, defined as containing between 20 and 47% iron, is thought to be the primary\\u000a iron-bearing lithology from which most high-grade ore deposits formed, through different processes of enrichment. The low-grade\\u000a iron ores

G. du Plessis; G. J. Jonck; R. Kruger

1997-01-01

266

Comparative Effects of Iron Deficiency Induced by Bleeding and a Low-Iron Diet on the Intestinal Absorptive Interactions of Iron, Cobalt, Manganese, Zinc, Lead and Cadmium1  

Microsoft Academic Search

Dietary iron deficiency enhances the absorption of iron, cobalt, manganese, zinc, cadmium and lead, whereas, iron deficiency due to bleeding in creases the absorption of iron, cobalt and perhaps manganese. To determine whether the response to bleeding is qualitatively different from that induced by dietary iron deficiency, metal absorption was studied in mice fed either a high- iron diet (120

PETER R. FLANAGAN; JAMES HAIST; LESLIE S. VALBERG

267

Adiposity in women and children from transition countries predicts decreased iron absorption, iron deficiency and a reduced response to iron fortification  

Microsoft Academic Search

Background:Overweight is increasing in transition countries, while iron deficiency remains common. In industrialized countries, greater adiposity increases risk of iron deficiency. Higher hepcidin levels in obesity may reduce dietary iron absorption. Therefore, we investigated the association between body mass index (BMI) and iron absorption, iron status and the response to iron fortification in populations from three transition countries (Thailand, Morocco

M. B. Zimmermann; C. Zeder; S. Muthayya; P. Winichagoon; N. Chaouki; I. Aeberli; R. F. Hurrell

2008-01-01

268

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

NASA Astrophysics Data System (ADS)

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.

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

2014-01-01

269

Sequestration and Scavenging of Iron in Infection  

PubMed Central

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.

Parrow, Nermi L.; Fleming, Robert E.

2013-01-01

270

[Iron, hepcidin and chronic kidney disease].  

PubMed

Iron deficiency is commonly observed in chronic kidney disease. Blood loss and iron consumption under erythropiesis activating agents (ESA) induce absolute deficiency whereas defect of iron intestinal absorption and storage release account for functional deficiency. High hepcidin plasma levels are probably induced by inflammatory process and can explain functional deficiency. However, hepcidin is negatively correlated with ESA needs and hepcidin expression is influenced by other factors as degree of renal insufficiency, iron pool, treatments (iron IV and ESA). IV iron is the common therapeutic approach of iron deficiency and only normalized iron marrow supply cannot account for his efficiency. New IV iron products allow us to conceive new therapeutic schemes. Hepcidin inhibition is another therapeutic alternative. PMID:21186144

Fievet, Patrick; Brazier, François

2011-04-01

271

Mössbauer investigation of iron uptake in wheat  

NASA Astrophysics Data System (ADS)

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.

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

2008-07-01

272

[Iron metabolism: State of the art].  

PubMed

About 60% of body iron is associated with hemoglobin in circulating red blood cells and daily erythropoiesis requires about 25 to 30mg iron per day. This iron is provided by macrophages through recycling of heme iron following phagocytosis of senescent red blood cells and heme catabolism. Intestinal iron absorption (1 to 2mg per day) only compensates for daily iron losses. Hepcidin, a 25 amino-acid peptide synthesized in hepatocytes, secreted in plasma and rapidly removed in urines, is a negative regulator of both intestinal iron absorption and heme iron recycling by macrophages. Hepcidin synthesis is stimulated by iron or by inflammation (mostly by IL-6) and is repressed by iron deficiency and by all conditions that stimulate bone marrow erythropoiesis such as anemia, bleeding, hemolysis, dyserythropoiesis or erythropoietin injections. A defect in the activation of hepcidin normally triggered by iron excess is the underlying mechanism for all juvenile or adult forms of hemochromatosis whereas a defect in hepcidin repression is responsible for an iron deficiency iron refractory anemia (IRIDA). Reduced hepcidin filtration in renal insufficiency contributes to the associated anemia and stimulation of hepcidin synthesis by inflammation is a major determinant of the anemia of chronic disorders. New therapeutic perspectives are currently underway such as the development of agonists or antagonists of hepcidin or siRNA approaches aiming at reducing hepcidin synthesis. The validation of hepcidin assays in a near future will allow identifying the patients most likely to benefit from intravenous iron therapy. PMID:22595534

Beaumont, C; Karim, Z

2013-01-01

273

Regulation of Iron Metabolism by Pyrococcus furiosus  

PubMed Central

Iron is an essential element for the hyperthermophilic archaeon Pyrococcus furiosus, and many of its iron-containing enzymes have been characterized. How iron assimilation is regulated, however, is unknown. The genome sequence contains genes encoding two putative iron-responsive transcription factors, DtxR and Fur. Global transcriptional profiles of the dtxR deletion mutant (?DTXR) and the parent strain under iron-sufficient and iron-limited conditions indicated that DtxR represses the expression of the genes encoding two putative iron transporters, Ftr1 and FeoAB, under iron-sufficient conditions. Under iron limitation, DtxR represses expression of the gene encoding the iron-containing enzyme aldehyde ferredoxin oxidoreductase and a putative ABC-type transporter. Analysis of the dtxR gene sequence indicated an incorrectly predicted translation start site, and the corrected full-length DtxR protein, in contrast to the truncated version, specifically bound to the promoters of ftr1 and feoAB, confirming its role as a transcription regulator. Expression of the gene encoding Ftr1 was dramatically upregulated by iron limitation, but no phenotype was observed for the ?FTR1 deletion mutant under iron-limited conditions. The intracellular iron concentrations of ?FTR1 and the parent strain were similar, suggesting that under the conditions tested, Ftr1 is not an essential iron transporter despite its response to iron. In contrast to DtxR, the Fur protein appears not to be a functional regulator in P. furiosus, since it did not bind to the promoters of any of the iron-regulated genes and the deletion mutant (?FUR) revealed no transcriptional responses to iron availability. DtxR is therefore the key iron-responsive transcriptional regulator in P. furiosus.

Zhu, Yixuan; Kumar, Sunil; Menon, Angeli L.; Scott, Robert A.

2013-01-01

274

Iron: effect of overload and deficiency.  

PubMed

Iron is a redox active metal which is abundant in the Earth's crust. It has played a key role in the evolution of living systems and as such is an essential element in a wide range of biological phenomena, being critical for the function of an enormous array of enzymes, energy transduction mechanisms, and oxygen carriers. The redox nature of iron renders the metal toxic in excess and consequently all biological organisms carefully control iron levels. In this overview the mechanisms adopted by man to control body iron levels are described.Low body iron levels are related to anemia which can be treated by various forms of iron fortification and supplementation. Elevated iron levels can occur systemically or locally, each giving rise to specific symptoms. Systemic iron overload results from either the hyperabsorption of iron or regular blood transfusion and can be treated by the use of a selection of iron chelating molecules. The symptoms of many forms of neurodegeneration are associated with elevated levels of iron in certain regions of the brain and iron chelation therapy is beginning to find an application in the treatment of such diseases. Iron chelators have also been widely investigated for the treatment of cancer, tuberculosis, and malaria. In these latter studies, selective removal of iron from key enzymes or iron binding proteins is sought. Sufficient selectivity between the invading organism and the host has yet to be established for such chelators to find application in the clinic.Iron chelation for systemic iron overload and iron supplementation therapy for the treatment of various forms of anemia are now established procedures in clinical medicine. Chelation therapy may find an important role in the treatment of various neurodegenerative diseases in the near future. PMID:24470094

Hider, Robert C; Kong, Xiaole

2013-01-01

275

Disposition, accumulation and toxicity of iron fed as iron (II) sulfate or as sodium iron EDTA in rats.  

PubMed

A study was performed to provide data on the disposition, accumulation and toxicity of sodium iron EDTA in comparison with iron (II) sulfate in rats on administration via the diet for 31 and 61 days. Clinical signs, body weights, food consumption, food conversion efficiency, hematology, clinical chemistry and pathology of selected organs were used as criteria for disclosing possible harmful effects. Determination of iron and total iron binding capacity in blood plasma and non-heme iron analysis in liver, spleen and kidneys were used to assess the disposition and accumulation of iron originating from sodium iron EDTA or iron (II) sulfate. It was concluded that, under the conditions of the present study, iron is accumulated from the diet in liver, spleen and kidneys in a dose-dependent manner, and iron derived from FeEDTA is taken up and/or accumulated less efficiently in liver and spleen than iron from FeSO(4). Moreover, feeding iron up to 11.5 and 11.2 mg/kg body weight/day, derived from FeSO(4) and FeEDTA, respectively, did not result in tissue iron excess nor in any other toxicologically significant effects. PMID:11278058

Appel, M J; Kuper, C F; Woutersen, R A

2001-03-01

276

Metabolic crossroads of iron and copper  

PubMed Central

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.

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

2013-01-01

277

[Investigations of the bioavailability of iron from bi- and trivalent iron salts (author's transl)].  

PubMed

In a clinical pilot study, performed as an intraindividual comparison, 3 oral iron preparations, one bivalent iron sulfate (quick release stick capsule preparation) and two trivalent iron citrate complex preparations with different additives, were investigated on 9 healthy young male test persons by the iron absorption test (postabsorption serum iron concentration curves) in order to study the bioavailability of these drugs and their compatibility. Whereas both iron drugs proved equally compatible when administered in therapeutical doses, it was again confirmed that the enteral bioavailability of the ferrous iron sulfate is superior to that of the ferric iron complex preparation. According to these results the medication of ferric iron preparations seems once again to be proved unsuitable, trivalent iron having first to be reduced to bivalent absorbable iron, there however being usually not enough "reducing capacity" in the gastrointestinal tract to do this. PMID:853979

Dietzfelbinger, H; Kaboth, W

1977-04-15

278

Iron isotope composition of some Archean and Proterozoic iron formations  

NASA Astrophysics Data System (ADS)

Fe isotopes can provide new insight into redox-dependent biogeochemical processes. Precambrian iron formations (IF) are deserving targets for Fe isotope studies because they are composed predominantly of authigenic Fe phases and record a period of unprecedented iron deposition in Earth's history. We present Fe isotope data for bulk samples from 24 Archean and Proterozoic IF and eight Phanerozoic Fe oxide-rich deposits. These data reveal that many Archean and early Paleoproterozoic iron formations were a sink for isotopically heavy Fe, in contrast to later Proterozoic and Phanerozoic Fe oxide-rich rocks. The positive ?56Fe values in IF are best explained by delivery of particulate ferric oxides formed in the water column to the sediment-water interface. Because IF are a net sink for isotopically heavy Fe, there must be a corresponding pool of isotopically light Fe in the sedimentary record. Earlier work suggested that Archean pyritic black shales were an important part of this light sink before 2.35 billion years ago (Ga). It is therefore likely that the persistently and anomalously low ?56Fe values in shales are linked with the deposition of isotopically heavy Fe in IF in the deeper parts of basins. IF deposition produced a residual isotopically light dissolved Fe pool that was captured by pyritic Fe in shales. Local dissimilatory Fe reduction in porewater and associated diagenetic reactions resulting in pyrite and carbonate precipitation may have further enhanced Fe isotope heterogeneity in marine sediments, and an 'iron shuttle' may have transported isotopically light Fe from shelf sediments to the basin. Nevertheless, water-column processing of hydrothermally delivered Fe likely had the strongest influence on the bulk iron isotope composition of Archean and Paleoproterozoic iron formations and other marine sediments.

Planavsky, Noah; Rouxel, Olivier J.; Bekker, Andrey; Hofmann, Axel; Little, Crispin T. S.; Lyons, Timothy W.

2012-03-01

279

Laser cooling of Iron atoms  

NASA Astrophysics Data System (ADS)

We report on the first laser cooling of Iron atoms. Our laser cooling setup makes use of 2 UV laser radiation sent colinearly in a 0.8 m Zeeman slower. One laser is meant for optical pumping of the Iron atoms from the ground state to the lowest energy metastable state. The second laser cools down the atoms using a quasi-perfect closed transition from the optical pumped metastable state. The velocity distribution at the exit of the Zeeman slower is obtained from a probe laser crossing the atom beam at an angle of 50 degrees. The fluorescence light is detected using a photomultiplier tube coupled with a boxcar analyzer. The Iron atom beam is produced with a commercial effusion cell working at around 1950 K. Our laser radiations are stabilized using standard saturated-absorption signals in both an Iron hollow cathode absorption cell and an Iodine cell. We will present our experimental setup, as well as the first evidences of cooled down Iron atoms at the exit of the Zeeman slower.

Bastin, Thierry; Huet, Nicolas; Krins, Stephanie

2013-03-01

280

Sonochemical synthesis of iron colloids  

SciTech Connect

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.

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

1996-11-27

281

Hepatic iron accumulation over time in European starlings (Sturnus vulgaris) fed two levels of iron.  

PubMed

European starlings (Sturnus vulgaris) were used as a passerine bird model to examine the effect of dietary iron on the level of hepatic iron in birds. Nestling and fledgling starlings (n = 56) were raised on a controlled-iron diet. When birds maintained constant body weight, they were assigned in pairs to cages, and baseline sampling was performed. Pairs were then assigned to one of two diets: the controlled-iron diet (168 ppm, dry basis) or a high-iron diet (3,035 ppm, dry basis). Dry-matter intake and iron consumption were recorded. Dry-matter intake did not differ between the dietary treatment groups and was stable during treatment periods. Iron intake was higher in the high-iron group (P < 0.05). Birds were euthanized at baseline, 8 wk, and 16 wk. Body, liver, and spleen weights were measured. Hepatic iron and copper concentrations were determined. Body weight did not differ between the two treatment groups or among individuals for the study duration. Liver iron concentration differed over time and between treatment groups. Birds receiving both treatments had similar liver iron content at week 8 (3,107 +/- 228.6 ppm and 3,122 +/- 306.2 ppm high and controlled iron, respectively; P > 0.05), but by week 16, birds consuming the high-iron diet had greater hepatic iron levels than those consuming the controlled-iron diet (5,929 +/- 937.2 ppm and 3,683 +/- 229.5 ppm high and controlled iron, respectively; P < 0.05). Birds on the controlled-iron diet also had higher hepatic iron at 16 wk than at 8 wk. Liver copper decreased over time in all birds regardless of treatment. Results show that both dietary iron level and duration of time influenced hepatic iron storage. The controlled-iron diets still allowed accumulation of hepatic iron in an 8-wk period. PMID:11428395

Crissey, S D; Ward, A M; Block, S E; Maslanka, M T

2000-12-01

282

The world iron and steel industry and its impact on Indiana iron and steel and electric utility industries  

NASA Astrophysics Data System (ADS)

In this research, a large scale mathematical programming model is developed to represent steel production and distribution. This model is used to investigate how technological changes, environmental restrictions, and government trade policies will affect future production location and relocation, world energy consumption, environmental pollution, and international trade in steel. Future potential relocation of production capacity of the world iron and steel industry will have substantial impacts on the North American electric utility industry, especially in Indiana. Given that the iron and steel industry is among the most energy intensive industries in North America, the electricity consumption of Indiana in particular is expected to change significantly as the industry adjusts to the changing environment. This research models the iron and steel industry in its use of two types of mills: integrated mills and mini-mills. Integrated mills use complex and capital intensive production processes to produce steel from iron ore, using a combination of the blast furnace and basic oxygen furnace. Mini-mills use electric melters which convert mainly scrap or directly reduced iron to steel. The model can reflect the trade and energy consequences of a chosen pattern of steel production, as well as the constraints on the pollutant generation. It also reflects various government trade policies to protect domestic steel production, such as quotas and protective tariffs. In addition, the model minimizes the total cost of steel production and transportation by evaluating the geographic patterns of the following factors: (1) iron and steel production; (2) new facility construction; (3) trade patterns. These factors are each subject to various constraints, such as demands, environmental restrictions, and government trade policies, imposed on the pattern of production. Optimization is performed for a single target year far enough in the future to allow construction of new capacity. The model also captures the transitional competition between the existing and the new capacities. Results indicate how future technological changes, environmental concerns and restrictions, and government trade policies can influence the iron and steel industry and the electric consumption of Indiana.

Leung, Thomas Cheong-Yuen

283

Direct Biohydrometallurgical Extraction of Iron from Ore  

SciTech Connect

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.

T.C. Eisele

2005-10-01

284

Iron acquisition and allocation in stramenopile algae.  

PubMed

The essential element iron has a low biological availability in the surface ocean where photosynthetic organisms live. Recent advances in our understanding of iron acquisition mechanisms in brown algae and diatoms (stramenopile algae) show the importance of the reduction of ferric to ferrous iron prior to, or during, transport in the uptake process. The uses of iron in photosynthetic stramenopiles resembles that in other oxygenic organisms, although (with the exception of the diatom Thalassiosira oceanica from an iron-deficient part of the ocean) they lack plastocyanin, instead using cytochrome c 6, This same diatom further economizes genotypically on the use of iron in photosynthesis by decreasing the expression of photosystem I, cytochrome c 6, and the cytochrome b 6 f complex per cell and per photosystem II relative to the coastal Thalassiosira pseudonana; similar changes occur phenotypically in response to iron deficiency in other diatoms such as Phaeodactylum tricornutum. In some diatoms grown under iron-limiting conditions, essentially all of the iron in the cells can be accounted for by the iron occurring in catalytic proteins. However, stramenopiles can store iron. Genomic studies show that pennate, but not centric, diatoms have the iron storage protein ferritin. While Mössbauer and X-ray analysis of (57)Fe-labelled Ectocarpus siliculosus shows iron in an amorphous mineral phase resembling the core of ferritin, the genome shows no protein with significant sequence similarity to ferritin. PMID:23658428

Raven, John A

2013-05-01

285

Iron homeostasis and toxicity in retinal degeneration  

PubMed Central

Iron is essential for many metabolic processes but can also cause damage. As a potent generator of hydroxyl radical, the most reactive of the free radicals, iron can cause considerable oxidative stress. Since iron is absorbed through diet but not excreted except through menstruation, total body iron levels build up with age. Macular iron levels increase with age, in both men and women. This iron has the potential to contribute to retinal degeneration. Here we present an overview of the evidence suggesting that iron may contribute to retinal degenerations. Intraocular iron foreign bodies cause retinal degeneration. Retinal iron buildup resulting from hereditary iron homeostasis disorders aceruloplasminemia, Friedreich’s Ataxia, and panthothenate kinase associated neurodegeneration cause retinal degeneration. Mice with targeted mutation of the iron exporter ceruloplasmin have age-dependent retinal iron overload and a resulting retinal degeneration with features of age-related macular degeneration (AMD). Post mortem retinas from patients with AMD have more iron and the iron carrier transferrin than age- matched controls. Over the past ten years much has been learned about the intricate network of proteins involved in iron handling. Many of these, including transferrin, transferrin receptor, divalent metal transporter 1, ferritin, ferroportin, ceruloplasmin, hephaestin, iron regulatory protein, and histocompatibility leukocyte antigen class I-like protein involved in iron homeostasis (HFE) have been found in the retina. Some of these proteins have been found in the cornea and lens as well. Levels of the iron carrier transferrin are high in the aqueous and vitreous humors. The functions of these proteins in other tissues, combined with studies on cultured ocular tissues, genetically engineered mice, and eye exams on patients with hereditary iron diseases provide clues regarding their ocular functions. Iron may play a role in a broad range of ocular diseases, including glaucoma, cataract, AMD, and conditions causing intraocular hemorrhage. While iron deficiency must be prevented, the therapeutic potential of limiting iron induced ocular oxidative damage is high. Systemic, local, or topical iron chelation with an expanding repertoire of drugs has clinical potential.

He, Xining; Hahn, Paul; Iacovelli, Jared; Wong, Robert; King, Chih; Bhisitkul, Robert; Massaro-Giordano, Mina; Dunaief, Joshua L.

2007-01-01

286

Magnetism in dense hexagonal iron.  

PubMed

The magnetic state of hexagonal close-packed iron has been the subject of debate for more than three decades. Although Mössbauer measurements find no evidence of the hyperfine splitting that can signal the presence of magnetic moments, density functional theory predicts an antiferromagnetic (afm) ground state. This discrepancy between theory and experiment is now particularly important because of recent experimental findings of anomalous splitting in the Raman spectra and the presence of superconductivity in hexagonal close-packed iron, which may be caused by magnetic correlations. Here, we report results from first principles calculations on the previously predicted theoretical collinear afm ground state that strongly support the presence of afm correlations in hexagonal close-packed iron. We show that anomalous splitting of the Raman mode can be explained by spin-phonon interactions. Moreover, we find that the calculated hyperfine field is very weak and would lead to hyperfine splitting below the resolution of Mössbauer experiments. PMID:14694193

Steinle-Neumann, Gerd; Stixrude, Lars; Cohen, Ronald E

2004-01-01

287

Magnetism in dense hexagonal iron  

PubMed Central

The magnetic state of hexagonal close-packed iron has been the subject of debate for more than three decades. Although Mössbauer measurements find no evidence of the hyperfine splitting that can signal the presence of magnetic moments, density functional theory predicts an antiferromagnetic (afm) ground state. This discrepancy between theory and experiment is now particularly important because of recent experimental findings of anomalous splitting in the Raman spectra and the presence of superconductivity in hexagonal close-packed iron, which may be caused by magnetic correlations. Here, we report results from first principles calculations on the previously predicted theoretical collinear afm ground state that strongly support the presence of afm correlations in hexagonal close-packed iron. We show that anomalous splitting of the Raman mode can be explained by spin–phonon interactions. Moreover, we find that the calculated hyperfine field is very weak and would lead to hyperfine splitting below the resolution of Mössbauer experiments.

Steinle-Neumann, Gerd; Stixrude, Lars; Cohen, Ronald E.

2004-01-01

288

Heterometallic (iron, cobalt) dioximates  

SciTech Connect

The polynuclear heterometallic (iron, cobalt) dioximates FeCoD/sub 2/Cl/sub 2/(C/sub 5/H/sub 5/N)/sub 2/ x 2H/sub 2/O (I), Fe/sub 2/CoD/sub 2/(DH)/sub 2/Cl/sub 3/(H/sub 2/O)/sub 3/ (II), and Fe/sub 2/CoD/sub 2/(DH)/sub 2/Cl/sub 2/(4-CH/sub 3/C/sub 5/H/sub 4/N)/sub 2/(H/sub 2/O)/sub 2/ (III) (DH/sub 2/ stands for dimethylglyoxime) have been synthesized. An investigation of I-III by Moessbauer spectroscopy has shown that high-spin Fe(III) ions appear in an octahedral hexaoxygen or mixed oxygen-halide environment involving the oxygen atoms of the hydroxyimino groups of DH/sub 2/ and the water molecules as well as the chloride ions. In III along with the Fe(III) ions there are Fe(II) ions in an Fe(III): Fe(II) ratio equal to 1:1 in a low-spin state in an environment of six nitrogen atoms from the DH/sub 2/ and 4-CH/sub 3/C/sub 5/H/sub 4/N molecules. An analysis of the IR spectra (400-4000 cm/sup -1/) has provided evidence of the presence of an MN/sub 4/ dioximate chelate grouping and coordinated molecules of the amine and evidence of the absence of intramolecular hydrogen bonding in I-III. The values of ..mu../sub eff/ for I-III (295/sup 0/K) correspond to Fe(III) with S = 5/2. A thermogravimetric investigation of I-III has shown that the temperature for their complete decomposition ranges from 195 to 240 /sup 0/C. The elimination of 4-CH/sub 3/C/sub 5/H/sub 4/N has been characterized by kinetic parameters.

Samus, N.M.; Khoroshun, I.V.; Yushchenko, S.P.; Turte, K.I.

1988-04-01

289

Bioavailability of bi- and trivalent oral iron preparations. Investigations of iron absorption by postabsorption serum iron concentrations curves.  

PubMed

Since 1977 the bioavailability of 14 bi- and trivalent oral iron preparations has been investigated in five separate orientated clinical studies by using postabsorption serum iron concentration curves. The range of relative bioavailability was 46 to 100% in the first group of preparations, 31 to 47% in the second group and 6 to 29% in the third group. The first group contained mainly bivalent quick release preparations, the second group slow or sustained release preparations and the third mainly trivalent iron preparations. The postabsorption serum iron concentration curves which show a good congruence with exact 59Fe whole body retention tests again confirmed the nearly 50-year-old rule that bivalent iron is up to 16 times better absorbed than trivalent iron. There is no doubt that the oral iron preparations of good bioavailability are able to cure an iron deficiency more rapidly than iron preparations with a low bioavailability. This therefore has a clear influence on the overall expense of iron therapy. Only those preparations from the first group can be recommended for oral iron therapy. The preparations in the second group are less suitable and those in the third group should be excluded from iron therapy in all countries. PMID:3566864

Dietzfelbinger, H

1987-01-01

290

Antioxidant capacity of parsley cells (Petroselinum crispum L.) in relation to iron-induced ferritin levels and static magnetic field.  

PubMed

This study was aimed to evaluate antioxidant response of parsley cells to 21 ppm iron and static magnetic field (SMF; 30 mT). The activity of catalase (CAT) and ascorbate peroxidase (APX) and the contents of malonyldialdehyde, iron and ferritin were measured at 6 and 12 h after treatments. Exposure to SMF increased the activity of CAT in treated cells, while combination of iron and SMF treatments as well as iron supply alone decreased CAT activity, compared to that of control cells. Combination of SMF with iron treatment reduced iron content of the cells and ameliorated mal effect of iron on CAT activity. All treatments reduced APX activity; however, the content of total ascorbate increased in response to iron and SMF+iron. The results showed that among the components of antioxidant system of parsley cells, enhanced activity of CAT in SMF-treated cells and increase of ascorbate in SMF+Fe-treated ones were responsible for the maintenance of membranes integrity. Ferritin contents of SMF- and SMF+Fe-treated cells also decreased significantly 12 h after treatments, compared to those of the control cells. These results cast doubt on the proposed functions of ferritin as a putative reactive oxygen species detoxifying molecule. PMID:23323716

Rajabbeigi, Elham; Ghanati, Faezeh; Abdolmaleki, Parviz; Payez, Atefeh

2013-12-01

291

Iron, hepcidin, and the metal connection.  

PubMed

Identification of new players in iron metabolism, such as hepcidin, which regulates ferroportin and divalent metal transporter 1 expression, has improved our knowledge of iron metabolism and iron-related diseases. However, from both experimental data and clinical findings, "iron-related proteins" appear to also be involved in the metabolism of other metals, especially divalent cations. Reports have demonstrated that some metals may affect, directly or indirectly, the expression of proteins involved in iron metabolism. Throughout their lives, individuals are exposed to various metals during personal and/or occupational activities. Therefore, better knowledge of the connections between iron and other metals could improve our understanding of iron-related diseases, especially the variability in phenotypic expression, as well as a variety of diseases in which iron metabolism is secondarily affected. Controlling the metabolism of other metals could represent a promising innovative therapeutic approach. PMID:24926268

Loréal, Olivier; Cavey, Thibault; Bardou-Jacquet, Edouard; Guggenbuhl, Pascal; Ropert, Martine; Brissot, Pierre

2014-01-01

292

Iron, hepcidin, and the metal connection  

PubMed Central

Identification of new players in iron metabolism, such as hepcidin, which regulates ferroportin and divalent metal transporter 1 expression, has improved our knowledge of iron metabolism and iron-related diseases. However, from both experimental data and clinical findings, “iron-related proteins” appear to also be involved in the metabolism of other metals, especially divalent cations. Reports have demonstrated that some metals may affect, directly or indirectly, the expression of proteins involved in iron metabolism. Throughout their lives, individuals are exposed to various metals during personal and/or occupational activities. Therefore, better knowledge of the connections between iron and other metals could improve our understanding of iron-related diseases, especially the variability in phenotypic expression, as well as a variety of diseases in which iron metabolism is secondarily affected. Controlling the metabolism of other metals could represent a promising innovative therapeutic approach.

Loreal, Olivier; Cavey, Thibault; Bardou-Jacquet, Edouard; Guggenbuhl, Pascal; Ropert, Martine; Brissot, Pierre

2014-01-01

293

Mechanisms of iron metabolism in Caenorhabditis elegans  

PubMed Central

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.

Anderson, Cole P.; Leibold, Elizabeth A.

2014-01-01

294

Food iron and lead absorption in humans.  

PubMed

Food iron and lead absorption were measured simultaneously in 28 subjects by extrinsically labeling three consecutive meals with the radioactive tracers, iron 59-sulfate and lead 203-chloride. Absorption was measured directly in all subjects by whole-body counting and indirectly in 15 subjects by assessing subsequent levels of tracer in blood. Iron status of the subjects ranged from iron deficient to replete, thus providing a wide range of iron absorption. Statistically significant positive correlations were obtained between food-iron and lead absorption measured by whole-body counting and also between the tracer levels of iron and lead in the blood. However, the correlation between the absorption of the two elements was not strong, as evidenced by the fact that only 50% of the subjects who hyperabsorbed iron also hyperabsorbed lead. PMID:3728362

Watson, W S; Morrison, J; Bethel, M I; Baldwin, N M; Lyon, D T; Dobson, H; Moore, M R; Hume, R

1986-08-01

295

Prereduced Iron Ore Pellets: Preparation, Properties, Utilization.  

National Technical Information Service (NTIS)

A process for simultaneously reducing and indurating iron ore pellets was developed by Bureau of Mines laboratory research and confirmed on a continuous pilot plant basis. Moist iron ore concentrate was balled, mixed with solid reductant, and heated at ab...

M. M. Fine N. B. Melcher

1970-01-01

296

Selected properties of iron aluminides  

SciTech Connect

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.

Schneibel, J.H.

1994-09-01

297

49 CFR 192.487 - Remedial measures: Distribution lines other than cast iron or ductile iron lines.  

Code of Federal Regulations, 2010 CFR

... (a) General corrosion. Except for cast iron or ductile iron pipe, each segment of generally corroded distribution...Localized corrosion pitting. Except for cast iron or ductile iron pipe, each segment of distribution line pipe with...

2009-10-01

298

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

Microsoft Academic Search

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

Lijian Wang; Bobby J. Cherayil

2009-01-01

299

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

Microsoft Academic Search

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

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

2007-01-01

300

Controlling iron availability to phytoplankton in iron-replete coastal waters  

Microsoft Academic Search

Recent work demonstrates that the micronutrient iron may strongly influence the magnitude and character of algal production in nearshore waters due in part to the higher but variable iron requirements of neritic phytoplankton. However, ascertaining the direct effects of iron nutrition in coastal waters has been forestalled by our inability to experimentally regulate ambient iron availability independent of other factors.

Mark L. Wells; Charles G. Trick

2004-01-01

301

A new refining process for iron oxide using iron ore and its application to hard ferrites  

NASA Astrophysics Data System (ADS)

Kawasaki Steel Corporation and Kawatetsu Mining Co., Ltd. have developed a new refining process to extract iron oxide from iron ore to meet the increase in demand for iron oxide for high- grade hard ferrites. This article discusses the quality of iron oxides and the characteristics of the hard ferrite magnets produced from them.

Nakashima, S.; Ikeda, Y.; Hirose, S.; Nakamura, H.; Ito, T.

1992-03-01

302

The importance of non-transferrin bound iron in disorders of iron metabolism  

Microsoft Academic Search

The concept of non-transferrin bound iron (NTBI) was introduced 22 years ago by Hershko et al. (Brit. J. Haematol. 40 (1978) 255). It stemmed from a suspicion that, in iron overloaded patients, the large amounts of excess iron released into the circulation are likely to exceed the serum transferrin (Tf) iron-binding capacity (TIBC), leading to the appearance of various forms

W Breuer; C Hershko; Z. I Cabantchik

2000-01-01

303

Size and composition control of core-shell structured iron\\/iron-oxide nanoparticles  

Microsoft Academic Search

Metallic iron nanoparticles with a crystalline iron oxide shell were synthesized by the thermal decomposition of iron pentacarbonyl [Fe(CO)5] in octadecene in the presence of oleic acid and oleylamine. The effect of different synthetic parameters was investigated in details including the refluxing time and temperature, the injection temperature of iron precursor and the surfactant concentrations. The particles size can be

H. Khurshid; V. Tzitzios; Wanfeng Li; C. G. Hadjipanayis; G. C. Hadjipanayis

2010-01-01

304

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

Code of Federal Regulations, 2013 CFR

...2013-10-01 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...

2013-10-01

305

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

Microsoft Academic Search

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,

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

1988-01-01

306

A new refining process for iron oxide using iron ore and its application to hard ferrites  

Microsoft Academic Search

Kawasaki Steel Corporation and Kawatetsu Mining Co., Ltd. have developed a new refining process to extract iron oxide from\\u000a iron ore to meet the increase in demand for iron oxide for high- grade hard ferrites. This article discusses the quality of\\u000a iron oxides and the characteristics of the hard ferrite magnets produced from them.

S. Nakashima; Y. Ikeda; S. Hirose; H. Nakamura; T. Ito

1992-01-01

307

Intestinal HIF2? promotes tissue-iron accumulation in disorders of iron overload with anemia.  

PubMed

Several distinct congenital disorders can lead to tissue-iron overload with anemia. Repeated blood transfusions are one of the major causes of iron overload in several of these disorders, including ?-thalassemia major, which is characterized by a defective ?-globin gene. In this state, hyperabsorption of iron is also observed and can significantly contribute to iron overload. In ?-thalassemia intermedia, which does not require blood transfusion for survival, hyperabsorption of iron is the leading cause of iron overload. The mechanism of increased iron absorption in ?-thalassemia is unclear. We definitively demonstrate, using genetic mouse models, that intestinal hypoxia-inducible factor-2? (HIF2?) and divalent metal transporter-1 (DMT1) are activated early in the pathogenesis of ?-thalassemia and are essential for excess iron accumulation in mouse models of ?-thalassemia. Moreover, thalassemic mice with established iron overload had significant improvement in tissue-iron levels and anemia following disruption of intestinal HIF2?. In addition to repeated blood transfusions and increased iron absorption, chronic hemolysis is the major cause of tissue-iron accumulation in anemic iron-overload disorders caused by hemolytic anemia. Mechanistic studies in a hemolytic anemia mouse model demonstrated that loss of intestinal HIF2?/DMT1 signaling led to decreased tissue-iron accumulation in the liver without worsening the anemia. These data demonstrate that dysregulation of intestinal hypoxia and HIF2? signaling is critical for progressive iron overload in ?-thalassemia and may be a novel therapeutic target in several anemic iron-overload disorders. PMID:24282296

Anderson, Erik R; Taylor, Matthew; Xue, Xiang; Ramakrishnan, Sadeesh K; Martin, Angelical; Xie, Liwei; Bredell, Bryce X; Gardenghi, Sara; Rivella, Stefano; Shah, Yatrik M

2013-12-10

308

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

ERIC Educational Resources Information Center

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)

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

1982-01-01

309

Effects of High Dietary HEME Iron and Radiation on Cardiovascular Function  

NASA Technical Reports Server (NTRS)

The radiation related health risks to astronauts is of particular concern to NASA. Data support that exposure to radiation is associated with a number of disorders including a heightened risk for cardiovascular diseases. Independent of radiation, altered nutrient status (e.g. high dietary iron) also increases ones risk for cardiovascular disease. However, it is unknown whether exposure to radiation in combination with high dietary iron further increases ones cardiovascular risk. The intent of our proposal is to generate compulsory data examining the combined effect of radiation exposure and iron overload on sensitivity to radiation injury to address HRP risks: 1) Risk Factor of Inadequate Nutrition; 2) Risk of Cardiac Rhythm Problems; and 3) Risk of Degenerative Tissue or other Health Effects from Space Radiation. Towards our goal we propose two distinct pilot studies using the following specific aims: Vascular Aim 1: To determine the short-term consequences of the independent and combined effects of exposure to gamma radiation and elevated body iron stores on measures of endothelial function and cell viability and integrity. We hypothesize that animals that have high body iron stores and are exposed to gamma radiation will show a greater reduction in endothelial dependent nitric oxid production and larger pathological changes in endothelial integrity than animals that have only 1 of those treatments (either high iron stores or exposure to gamma radiation). Vascular Aim 2: Identify and compare the effects of gamma radiation and elevated body iron stores on the genetic and epigenetic regulation of proteins associated with endothelial cell function. We hypothesize that modifications of epigenetic control and posttranslational expression of proteins associated with endothelial cell function will be differentially altered in rats with high body iron stores and exposed to gamma radiation compared to rats with only 1 type of treatment. Cardiac Aim 1: To determine the short-term consequences of the independent and combined effects of gamma radiation and elevated body iron stores on measures of cardiac structure. We hypothesize that modifications to cardiac structure and function will be greater in rats with high body iron stores and exposed to gamma radiation than in rats that have only 1 of those treatments. Cardiac Aim 2: Identify and compare the effects of gamma radiation and elevated body iron stores on the genetic and epigenetic regulation of proteins associated with cardiac structure and function. We hypothesize that modifications of epigenetic control and posttranslational expression of proteins associated with cardiac contractile function will be differentially altered in rats with high body iron stores and exposed to gamma radiation compared to rats with only 1 type of treatment.

Westby, Christian M.; Brown, A. K.; Platts, S. H.

2012-01-01

310

Iron-oxo complexes: Elusive iron(V) species identified  

NASA Astrophysics Data System (ADS)

A (hydroxo)oxoiron(V) oxidant has been implicated in cis-dihydroxylation reactions catalysed by Rieske dioxygenases and biomimetic non-haem iron complexes, but with only indirect proof of its existence. Variable-temperature mass spectrometry now provides persuasive evidence for just such a reactive intermediate in a synthetic system.

McDonald, Aidan R.; Que, Lawrence

2011-10-01

311

Microporation and 'Iron' tophoresis for treating Iron deficiency anemia  

PubMed Central

Purpose Iontophoretic mediated transdermal delivery of ferric pyrophosphate (FPP) in combination with microneedle pretreatment was investigated as a potential treatment for iron deficiency anemia (IDA). Methods In vitro transdermal delivery studies were performed using hairless rat skin and pharmacodynamic studies were performed in hairless anemic rat model. The hematological and biochemical parameters like hemoglobin, hematocrit and % serum transferrin were monitored in rats at healthy, anemic condition and post treatment. Micropores created by the microneedles were visualized in histological skin sections after staining with hemotoxylin and eosin. The recovery of micropores was investigated in vivo by measuring Transepidermal water loss (TEWL) at different time points. Results The passive, microneedle and iontophoresis mediated delivery did not lead to significant improvement in hematological and biochemical parameters in anemic rats, when used individually. When iontophoresis (0.15 mA/cm2 for 4 hours) was combined with microneedle pretreatment (for 2 minutes), therapeutically adequate amount of FPP was delivered and there was significant recovery of rats from IDA. Conclusions Microneedle and iontophoresis mediated delivery of iron via transdermal route could be developed as a potential treatment for IDA. The transdermal controlled delivery of iron could become a potential, safe and effective alternative to parenteral iron therapy.

Modepalli, Naresh; Jo, Seongbong; Repka, Michael A.; Murthy, S. Narasimha

2012-01-01

312

Iron trafficking as an antimicrobial target  

Microsoft Academic Search

Iron is essential for the survival of most organisms. Microbial iron acquisition depends on multiple, sometimes complex steps,\\u000a many of which are not shared by higher eukaryotes. Depriving pathogenic microbes of iron is therefore a potential antimicrobial\\u000a strategy. The following minireview briefly describes general elements in microbial iron uptake pathways and summarizes some\\u000a of the current work aiming at their

Rosanne E. Frederick; Jeffery A. Mayfield; Jennifer L. DuBois

2009-01-01

313

Intranigral iron infusion in the rat  

Microsoft Academic Search

Iron is known to induce lipid perocidation and recent evidence indicates that both iron and lipid peroxidation are elevated\\u000a in the substantia nigra in Parkinson's disease (PD). To test whether excess intranigral iron induces lipid peroxidation, we\\u000a infused an iron citrate solution (0.63 nmol in 0.25 ?L) into the rat substantia nigra and measured nigral thiobarbituric acid\\u000a reactive products at

Gregory J. Sengstock; Nasser H. Zawia; Charles W. Olanow; Adrian J. Dunn; Gary W. Arendash

1997-01-01

314

Iron and its complexes in silicon  

NASA Astrophysics Data System (ADS)

This article is the first in a series of two reviews on the properties of iron in silicon. It offers a comprehensive of the current state of understanding of fundamental physical properties of iron and its complexes in silicon. The first section of this review discusses the position of iron in the silicon lattice and the electrical properties of interstitial iron. Updated expressions for the solubility and the diffusivity of iron in silicon are presented, and possible explanations for conflicting experimental data obtained by different groups are discussed. The second section of the article considers the electrical and the structural properties of complexes of interstitial iron with shallow acceptors (boron, aluminum, indium, gallium, and thallium), shallow donors (phosphorus and arsenic) and other impurities (gold, silver, platinum, palladium, zinc, sulfur, oxygen, carbon, and hydrogen). Special attention is paid to the kinetics of iron pairing with shallow acceptors, the dissociation of these pairs, and the metastability of iron-acceptor pairs. The parameters of iron-related defects in silicon are summarized in tables that include more than 30 complexes of iron as detected by electron paramagnetic resonance (EPR) and almost 20 energy levels in the band gap associated with iron. The data presented in this review illustrate the enormous complexing activity of iron, which is attributed to the partial or complete (depending on the temperature and the conductivity type) ionization of iron as well as the high diffusivity of iron in silicon. It is shown that studies of iron in silicon require exceptional cleanliness of experimental facilities and highly reproducible diffusion and temperature ramping (quenching) procedures. Properties of iron that are not yet completely understood and need further research are outlined.

Istratov, A. A.; Hieslmair, H.; Weber, E. R.

315

Anemia and Iron Deficiency in Developing Countries  

Microsoft Academic Search

Iron deficiency and anemia are major public health concerns throughout the world and are of special concern in many developing\\u000a countries where the incidence and severity of anemia in certain populations is very high. Pregnant women, women of childbearing\\u000a age, and young children are especially vulnerable to iron deficiency and iron-deficiency anemia (IDA) because of increased\\u000a iron needs during growth

Usha Ramakrishnan; Beth Imhoff-Kunsch

316

Intestinal iron absorption during suckling in mammals  

Microsoft Academic Search

The maintenance of appropriate iron levels is important for mammalian health, particularly during the rapid growth period\\u000a following birth. Too little iron can lead to irreversible damage to the developing central nervous system and too much iron\\u000a at this point can have adverse long term consequences, possibly due to excessive free radical production. In order to maintain\\u000a iron levels, intestinal

David M. Frazer; Deepak Darshan; Gregory J. Anderson

2011-01-01

317

EPR Spectra of Modified Iron Oxides  

Microsoft Academic Search

EPR spectra of iron oxides, obtained by calcination of iron oxide-hydroxides a-, ß-, ?- and d-FeOOH, and ruthenium catalysts based on them (Ru\\/Fe2O3 and Ru\\/Na-Fe2O3), used for the water-gas shift reaction (WGSR), were analyzed. The iron oxide (B) (obtained from ß-FeOOH) is inactive in WGSR. Deposition of ruthenium on iron oxide supports, in particular on those modified with sodium, enhanced

Anna Basi?ska; Wanda Wójtowicz; Andrzej B. Wi?ckowski; Florian Domka

2000-01-01

318

intestinal iron transport, is defective in the sla mouse  

Microsoft Academic Search

Iron is essential for many cellular functions; consequently, dis- turbances of iron homeostasis, leading to either iron deficiency or iron overload, can have significant clinical consequences. Despite the clinical prevalence of these disorders, the mecha- nism by which dietary iron is absorbed into the body is poorly understood. We have identified a key component in intestinal iron transport by study

Christopher D. Vulpe; Yien-Ming Kuo; Therese L. Murphy; Lex Cowley; Candice Askwith; Natasha Libina; Jane Gitschier; Gregory J. Anderson

319

Effect of Iron Fortification on Quality of Cheddar Cheese  

Microsoft Academic Search

Dairy products are an important source of nutrients but are low in iron. Iron fortification of cheese could increase average dietary iron intake about 14%. In three experiments, 14 cheeses were forti- fied with iron to evaluate iron recovery and cheese quality. Iron was added to 8 kg of pasteurized milk before starter cul- ture. Cheese quality was evaluated chemi-

Dejia Zhang; Arthur W. Mahoney

1989-01-01

320

Electron Energy Loss Spectroscopy (EELS) of Iron Fischer Tropsch Catalysts  

Microsoft Academic Search

Electron energy loss spectroscopy (EELS), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy have been used to study iron catalysts for Fischer Tropsch synthesis. When silica-containing iron oxide precursors are activated in flowing CO, the iron phase segregates into iron carbide crystallites, leaving behind some unreduced iron oxide in an amorphous state coexisting with the silica binder. The iron carbide

Aming Jin; Huifang Xu; Abhaya K. Datye

2006-01-01

321

Iron chaperones for mitochondrial Fe-S cluster biosynthesis and ferritin iron storage  

PubMed Central

Protein controlled iron homeostasis is essential for maintaining appropriate levels and availability of metal within cells. Recently, two iron chaperones have been discovered that direct metal within two unique pathways: (1) mitochondrial iron–sulfur (Fe–S) cluster assembly and (2) within the ferritin iron storage system. Although structural and functional details describing how these iron chaperones operate are emerging, both share similar iron binding affinities and metal–ligand site structures that enable them to bind and release Fe2+ to specific protein partners. Molecular details related to iron binding and delivery by these chaperones will be explored within this review.

Subramanian, Poorna; Rodrigues, Andria V; Ghimire-Rijal, Sudipa; Stemmler, Timothy L

2012-01-01

322

Intestinal Hypoxia Inducible Transcription Factors are Essential for Iron Absorption Following Iron Deficiency  

PubMed Central

Summary Iron deficiency and iron overload are among the most prevalent nutritional disorders worldwide. Duodenal cytochrome b (DcytB) and divalent metal transporter 1 (DMT1) are regulators of iron absorption. Their expression is increased during high systemic requirements for iron, but the molecular mechanisms that regulate DcytB and DMT1 expression are undefined. Hypoxia inducible factor (HIF) signaling was induced in the intestine following acute iron deficiency in the duodenum, resulting in activation of DcytB and DMT1 expression and an increase in iron uptake. DcytB and DMT1 were demonstrated as direct HIF-2? target genes. Genetic disruption of HIF signaling in the intestine abolished the adaptive induction of iron absorption following iron deficiency, resulting in low systemic iron and hematological defects. These results demonstrate that HIF signaling in the intestine is a critical regulator of systemic iron homeostasis.

Shah, Yatrik M.; Matsubara, Tsutomu; Ito, Shinji; Yim, Sun-Hee; Gonzalez, Frank J.

2008-01-01

323

Iron, brain ageing and neurodegenerative disorders  

Microsoft Academic Search

There is increasing evidence that iron is involved in the mechanisms that underlie many neurodegenerative diseases. Conditions such as neuroferritinopathy and Friedreich ataxia are associated with mutations in genes that encode proteins that are involved in iron metabolism, and as the brain ages, iron accumulates in regions that are affected by Alzheimer's disease and Parkinson's disease. High concentrations of reactive

Moussa B. H. Youdim; Peter Riederer; James R. Connor; Robert R. Crichton; Luigi Zecca

2004-01-01

324

Exploring Microbial Iron Oxidation in Wetland Soils  

Microsoft Academic Search

Iron is one of the most abundant elements on earth and is essential for life. Because of its importance, iron cycling and its interaction with other chemical and microbial processes has been the focus of many studies. Iron-oxidizing bacteria (FeOB) have been detected in a wide variety of environments. Among those is the rhizosphere of wetland plants roots which release

J. Wang; G. Muyzer; P. L. E. Bodelier; F. den Oudsten; H. J. Laanbroek

2009-01-01

325

Africa: The Birthplace of Iron Mining.  

ERIC Educational Resources Information Center

Describes the discovery in Swaziland of the oldest iron mining site known. Before this evidence that it was Africans who discovered iron mining and smelting around 42,000 B.C., it had been believed that the knowledge of iron originated in the Middle East between 550-1500 B.C. (GC)

Mutunhu, Tendai

1981-01-01

326

Carbonyl Iron Particles in Magnetic Cell Sorting  

Microsoft Academic Search

Iron-dextran microspheres are easily and inexpensively made by coating uniformly sized carbonyl iron particles with dextran. The iron-dextran spheres can be conjugated with a variety of ligands (antibodies, lectins, avidin, etc.) and used with a permanent rare earth magnet to remove cells, organelles, or macromolecules from mixtures and suspensions. The spheres can be stored indefinitely for use when they are

B. DeSales Lawless; Joann Williams

1993-01-01

327

Iron sulfide deposition during coal gasification  

Microsoft Academic Search

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

D. Duane Brooker; Myongsook S. Oh

1995-01-01

328

The Ins and Outs of Iron Homeostasis  

NSDL National Science Digital Library

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.

Adriana Donovan (Harvard Medical School, ChildrenÃÂs Hospital Boston, Dana-Farber Cancer Institute); Cindy N. Roy (Harvard Medical School ChildrenÃÂs Hospital Boston, Dana-Farber Cancer Institute); Nancy C. Andrews (Harvard Medical School ChildrenÃÂs Hospital Boston, Dana-Farber Cancer Institute,)

2006-04-01

329

Marine Siderophores and Microbial Iron Mobilization  

Microsoft Academic Search

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

Alison Butler

2005-01-01

330

Absorption of Hemoglobin Iron by the Rat.  

National Technical Information Service (NTIS)

In the rat the absorption of a test dose of hemoglobin or hemin iron59 was significantly less than a comparable dose of iron 59 as FeSO4. That this is of physiologic significance was demonstrated by producing a state of iron deficiency in animals raised o...

L. R. Weintraub M. E. Conard W. H. Crosby

1965-01-01

331

21 CFR 184.1375 - Iron, elemental.  

Code of Federal Regulations, 2013 CFR

...Drugs 3 2013-04-01 2013-04-01 false Iron, elemental. 184.1375 Section 184.1375...Specific Substances Affirmed as GRAS § 184.1375 Iron, elemental. (a) Iron, elemental (CAS Reg. No. 7439-89-6) is...

2013-04-01

332

Ligand iron catalysts for selective hydrogenation  

DOEpatents

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.

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

2010-11-16

333

Iron supplementation improves progressive fatigue resistance during dynamic knee extensor exercise in iron-depleted  

Microsoft Academic Search

Background: Tissue iron depletion may negatively affect endurance performance and muscle fatigability. Objective: We investigated tissue-level iron depletion and pro- gressive fatigue of the quadriceps during dynamic knee-extension exercise in young women. Design: Twenty iron-depleted (serum ferritin < 20 ? g\\/L), nonane- mic (hemoglobin > 110 g\\/L) women (x - ± SEM age: 29.1 ± 1.2 y) received iron (iron

Tom D Brutsaert; Sonia Hernandez-Cordero; Juan Rivera; Tracey Viola; Gail Hughes; Jere D Haas

334

Changes in biochemical indicators of iron status during iron repletion and depletion in monkeys.  

PubMed

Different modes of iron depletion and repletion were studied in monkeys to understand the sequential changes in and the relative importance of different biochemical indicators of iron status. Six control monkeys were divided into two groups, one was fed an iron-deficient diet (group 1) and the other underwent phlebotomy in addition to receiving an iron-deficient diet (group 2). Previously iron-depleted monkeys were subdivided into 4 groups of 3 animals each. While one group was continued on the iron-deficient diet (group 3), the second group received parenteral iron (group 4), the third group (group 5) received a sufficient-iron-containing diet, and the fourth group was fed 50% of the iron requirement. All indicators of iron status like hemoglobin (Hb), erythrocyte protoporphyrin (EPP), serum transferrin saturation and serum ferritin were monitored periodically, in addition to liver and bone marrow iron. all the indicators except serum ferritin and liver iron showed a decrease in group 2. On the other hand, animals receiving parenteral iron (group 4) showed an increase in all the parameters except serum ferritin. The dietary supplementation produced an increase in Hb and a decrease in EPP only (groups 5 and 6). There was a significant positive correlation between changes in bone marrow iron and Hb concentration depending on the severity of depletion and repletion. Both serum ferritin and liver iron did not respond to changes in dietary iron. Another parameter which responded to repletion was EPP. Serum ferritin and liver iron did not respond to changes in dietary iron or was not sensitive to subclinical iron deficiency. The results indicate that change in Hb is more sensitive to detect the deficiency of iron. It was also observed that different parameters respond variably under different modes of depletion and repletion. PMID:9267587

Sreeramulu, D; Nair, K M; Qadri, S S; Rao, K V; Sivakumar, B

1997-01-01

335

Evaluation of iron status in European adolescents through biochemical iron indicators: the HELENA Study  

Microsoft Academic Search

Background\\/Objectives:To assess the iron status among European adolescents through selected biochemical parameters in a cross-sectional study performed in 10 European cities.Subjects\\/Methods:Iron status was defined utilising biochemical indicators. Iron depletion was defined as low serum ferritin (SF8.5 mg\\/l) plus iron depletion. Iron deficiency anaemia (IDA) was defined as ID with haemoglobin (Hb) below the WHO cutoff for age and sex: 12.0

M Ferrari; L Mistura; E Patterson; M Sjöström; L E Díaz; P Stehle; M Gonzalez-Gross; M Kersting; K Widhalm; D Molnár; F Gottrand; S De Henauw; Y Manios; A Kafatos; L A Moreno; C Leclercq

2011-01-01

336

Iron-deficiency anemia and infant development: Effects of extended oral iron therapy  

Microsoft Academic Search

OBJECTIVE: To determine whether extended oral iron therapy corrects lower developmental test scores in infants with iron-deficiency anemia. STUDY DESIGN: Double-blind, controlled trial in Costa Rica involving 32 12- to 23-month-old infants with iron-deficiency anemia and 54 nonanemic control subjects. Anemic infants were treated with orally administered iron for 6 months; half the nonanemic children were treated with iron and

Betsy Lozoff; Abraham W. Wolf; Elias Jimenez

1996-01-01

337

Gold supported iron oxide–hydroxide derived from iron ore tailings for CO oxidation  

Microsoft Academic Search

Iron ore tailing, a waste material of iron ore industry, has been used to prepare iron oxide–hydroxide support for anchoring nano-gold particles. FeOOH was prepared from iron chloride solution obtained from acid digestion of iron ore tailing. Precipitation deposition method was used to prepare Au supported FeOOH. The samples were characterized by XRD, TEM, TG-DTA and FTIR. The XRD studies

R. Sakthivel; B. Das; B. Satpati; B. K. Mishra

2009-01-01

338

Consequences of Removing Iron Fortification of Flour on Iron Status among Danish Adults: Some Longitudinal Observations between 1987 and 1994  

Microsoft Academic Search

Background. Health authorities recommend that populations consume a diet providing sufficient iron, and in order to prevent iron deficiency, a number of countries have fortified certain foods with iron. In Denmark, flour was fortified with iron from 1954 until 1987, at which time the mandatory fortification was stopped. This study examines the effect of iron fortification on iron status by

Merete Osler; Nils Milman; Berit L. Heitmann

1999-01-01

339

Nucleation Mechanisms in Ductile Iron  

Microsoft Academic Search

The present paper reviews different mechanisms for graphite nucleation in ductile iron (DI) and how these are affected by the inoculation process. Theories describing the fundamentals of graphite formation are given and the strengths and weaknesses of each theory discussed. Effects of key elements in the nucleation process, such as silicon (Si), calcium (Ca), strontium (Sr), barium (Ba), aluminum (Al),

T. Skaland

340

Iron Deficiency and Bariatric Surgery  

PubMed Central

It is estimated that the prevalence of anaemia in patients scheduled for bariatric surgery is higher than in the general population and the prevalence of iron deficiencies (with or without anaemia) may be higher as well. After surgery, iron deficiencies and anaemia may occur in a higher percentage of patients, mainly as a consequence of nutrient deficiencies. In addition, perioperative anaemia has been related with increased postoperative morbidity and mortality and poorer quality of life after bariatric surgery. The treatment of perioperative anaemia and nutrient deficiencies has been shown to improve patients’ outcomes and quality of life. All patients should undergo an appropriate nutritional evaluation, including selective micronutrient measurements (e.g., iron), before any bariatric surgical procedure. In comparison with purely restrictive procedures, more extensive perioperative nutritional evaluations are required for malabsorptive procedures due to their nutritional consequences. The aim of this study was to review the current knowledge of nutritional deficits in obese patients and those that commonly appear after bariatric surgery, specifically iron deficiencies and their consequences. As a result, some recommendations for screening and supplementation are presented.

Jauregui-Lobera, Ignacio

2013-01-01

341

Coal desulfurization with iron pentacarbonyl  

NASA Technical Reports Server (NTRS)

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.

Hsu, G. C.

1979-01-01

342

Synthesis of iron oxide nanoworms  

NASA Astrophysics Data System (ADS)

We report on the synthesis of highly crystalline iron oxide nanoworms via a modified ``heat-up'' method using iron oleate as the precursor. According to a detailed nanoparticle growth study, we proposed that the nanoworms resulted from the aggregation of spherical iron oxide nanoparticles. The aggregation was induced by the high percentage coverage of a weakly bound ligand (trioctylphosphine oxide) on the iron oxide surfaces. A time dependent study clearly demonstrated the evolution of these nanostructures from spheres to one-dimensional nanoworms. The diameter of the nanoworms was similar to the spherical nanoparticles observed at an early stage of the reaction, and the length of the nanoworms changed from 50-200 nm during the reaction. The spheres and the nanoworms were both maghemite crystal structures, but the magnetic properties changed from superparamagnetic for the spheres to ferromagnetic for the elongated nanoworms. These one dimensional structures will offer additional opportunities for biomedical applications because of their high blood circulation time and large surface area for bio-labeling.

Palchoudhury, Soubantika; Xu, Yaolin; Goodwin, Johnny; Bao, Yuping

2011-04-01

343

Iron deficiency and bariatric surgery.  

PubMed

It is estimated that the prevalence of anaemia in patients scheduled for bariatric surgery is higher than in the general population and the prevalence of iron deficiencies (with or without anaemia) may be higher as well. After surgery, iron deficiencies and anaemia may occur in a higher percentage of patients, mainly as a consequence of nutrient deficiencies. In addition, perioperative anaemia has been related with increased postoperative morbidity and mortality and poorer quality of life after bariatric surgery. The treatment of perioperative anaemia and nutrient deficiencies has been shown to improve patients' outcomes and quality of life. All patients should undergo an appropriate nutritional evaluation, including selective micronutrient measurements (e.g., iron), before any bariatric surgical procedure. In comparison with purely restrictive procedures, more extensive perioperative nutritional evaluations are required for malabsorptive procedures due to their nutritional consequences. The aim of this study was to review the current knowledge of nutritional deficits in obese patients and those that commonly appear after bariatric surgery, specifically iron deficiencies and their consequences. As a result, some recommendations for screening and supplementation are presented. PMID:23676549

Jáuregui-Lobera, Ignacio

2013-05-01

344

Ironic Processes of Mental Control  

Microsoft Academic Search

A theory of ironic processes of mental control is proposed to account for the intentional and counterintentional effects that result from efforts at self-control of mental states. The theory holds that an attempt to control the mind introduces 2 processes: (a) an operating process that promotes the intended change by searching for mental contents consistent with the intended state and

Daniel M. Wegner

1994-01-01

345

Minerals Yearbook, 1989: Iron Ore.  

National Technical Information Service (NTIS)

The United States produced 59.03 million metric tons (Mmt) of usable iron ore during 1989. Although the tonnage was only slightly more than that of 1988, significant improvements were made in pellet quality. For the first time, fluxed pellets accounted fo...

P. H. Kuck C. M. Cvetic

1989-01-01

346

Neurodegeneration with brain iron accumulation.  

PubMed

Neurodegenerative disorders with brain iron accumulation (NBIA) are a clinically and genetically heterogeneous group of conditions in which there is neurodegeneration accompanied by elevated levels of brain iron. NBIA is frequently of genetic etiology, but may be secondary to an acquired systemic or neurological disease. Mutations in the ferritin light chain cause an adult-onset autosomal-dominant choreiform movement disorder termed neuroferritinopathy. Homozygous mutations in the ceruloplasmin gene cause aceruloplasminemia, which is characterized by the triad of diabetes, retinopathy, and a neurological disorder in mid adulthood. Mutations in pantothenate kinase 2 (PANK2) and phospholipase A2 (PLA2G6) cause recessive, childhood-onset extrapyramidal disorders termed pantothenate kinase-associated neurodegeneration (PKAN) and infantile neuroaxonal dystrophy (INAD), respectively. There is considerable phenotypic overlap between these conditions. The most useful investigation in suspected NBIA is brain magnetic resonance imaging, which can identify pathological iron deposition and distinguish between genotypes. Iron depletion therapy has been demonstrated to be successful in aceruloplasminemia, but not neuroferritinopathy, PKAN, or INAD. The presentation of NBIA overlaps with the more common adult movement disorders and pediatric neurometabolic conditions, and a high index of suspicion is required to make a correct diagnosis. PMID:21496576

McNeill, Alisdair; Chinnery, Patrick F

2011-01-01

347

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,...

348

Iron core in the sun?  

Microsoft Academic Search

A suggestion has been made that the sun may have a central core composed of iron (New Scientist, June 23, 1983). This suggestion is the latest attempt to force a fit to theoretical models of the sun's internal temperature structure. That the sun does not fit well enough as a model for compositional origin of the rest of the solar

Peter M. Bell

1983-01-01

349

Characterization of Synechocystis sp. PCC 6803 in iron-supplied and iron-deficient media.  

PubMed

The photosynthetic apparatus is rich in iron-containing cofactors and iron deficiency causes severe impairment of photosynthesis in plants, algae, and cyanobacteria. Synechocystis sp. PCC 6803 serves as a model system to investigate the complex assembly and integration of the multi-subunit protein complexes of oxygenic photosynthetic electron transport; particularly when coupled to developmental cues due to nutrient limitation or requirements. We study Fe(3+)-deficient and Fe(3+)-supplemented cultures of Synechocystis sp. PCC 6803. The autotrophic growth rate of Fe(3+)-deficient cultures is slower than Fe(3+)-supplemented cultures. Whole cell spectral analysis reveals differences in both the quantity and the peak absorbance of chlorophyll. Fe3+ deficiency decreases rates of photosynthetic electron transport and the mRNA and corresponding protein levels as observed using specific probes. mRNA levels of psaB increased 20-fold during recovery from Fe3+ deficiency, as compared to the control. psaD transcript levels increased to 160% during recovery as compared to the control. PsaA/B heterodimer formation and turnover is dependent on Fe3+ and the complete assembly on the reducing side of photosystem I (PS I) is PsaD-dependent. Recovery from Fe3+ deficiency suggests that regulation occurs at both the mRNA and protein level. PMID:8292789

Odom, W R; Hodges, R; Chitnis, P R; Guikema, J A

1993-12-01

350

Effects of Iron Deficiency on Iron Binding and Internalization into Acidic Vacuoles in Dunaliella salina1[W][OA  

PubMed Central

Uptake of iron in the halotolerant alga Dunaliella salina is mediated by a transferrin-like protein (TTf), which binds and internalizes Fe3+ ions. Recently, we found that iron deficiency induces a large enhancement of iron binding, which is associated with accumulation of three other plasma membrane proteins that associate with TTf. In this study, we characterized the kinetic properties of iron binding and internalization and identified the site of iron internalization. Iron deficiency induces a 4-fold increase in Fe binding, but only 50% enhancement in the rate of iron uptake and also increases the affinity for iron and bicarbonate, a coligand for iron binding. These results indicate that iron deprivation leads to accumulation and modification of iron-binding sites. Iron uptake in iron-sufficient cells is preceded by an apparent time lag, resulting from prebound iron, which can be eliminated by unloading iron-binding sites. Iron is tightly bound to surface-exposed sites and hardly exchanges with medium iron. All bound iron is subsequently internalized. Accumulation of iron inhibits further iron binding and internalization. The vacuolar inhibitor bafilomycin inhibits iron uptake and internalization. Internalized iron was localized by electron microscopy within vacuolar structures that were identified as acidic vacuoles. Iron internalization is accompanied by endocytosis of surface proteins into these acidic vacuoles. A novel kinetic mechanism for iron uptake is proposed, which includes two pools of bound/compartmentalized iron separated by a rate-limiting internalization stage. The major parameter that is modulated by iron deficiency is the iron-binding capacity. We propose that excessive iron binding in iron-deficient cells serves as a temporary reservoir for iron that is subsequently internalized. This mechanism is particularly suitable for organisms that are exposed to large fluctuations in iron availability.

Paz, Yakov; Shimoni, Eyal; Weiss, Meira; Pick, Uri

2007-01-01

351

Iron, anemia and hepcidin in malaria  

PubMed Central

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.

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

2014-01-01

352

In-situ identification of iron--zinc intermetallics in galvannealed steel coatings and iron oxides on exposed steel  

NASA Astrophysics Data System (ADS)

Identification of all the compounds present in various coatings on steels is particularly difficult. Non-destructive, in-situ analysis is necessary if the fraction of each compound as well as its probable layering within the coating, is to be determined. Mössbauer spectroscopy is one valuable probe capable of uniquely identifying all iron compounds which form as coatings on steel and other iron alloy surfaces. To investigate a complete coating several criteria need to be considered. Removing the coating inevitably leaves a small and perhaps important component intact on the substrate. Therefore investigating the coating as it remains intact on the steel is important if complete identification of the iron compounds is to be made. This also preserves crystalline texture or preferred growth orientation within the coating to which the Mössbauer effect is sensitive. Mössbauer spectroscopy is a non-destructive technique which allows the integrity of the coating to be maintained during analysis. The combined transmission and scattering Mössbauer geometries generally result in accurate analysis of the coating composition. For the scattering geometry added information on compound layering is obtained if separate Mössbauer spectra are recorded using the re-emitted gamma rays as well as the conversion electrons and subsequently emitted X-rays. In-situ scattering Mössbauer spectroscopy has been used to characterize the iron--zinc alloys which form in the coatings of commercially produced corrosion resistant galvannealed sheet steel, a product of great interest to automotive producers. The results show that different amounts of four iron--zinc phases are present depending on the production conditions of the coating. The different phases are also distinctly layered. Mössbauer analyses of corrosion coatings formed on the surface of steels which have been exposed to different environments has also been undertaken. Materials include structural steels exposed for up to 25 years in marine, rural and industrial environments, and the interior surfaces of boiler pipes subjected to adverse chemical and temperature environments.

Cook, Desmond C.

1998-12-01

353

Iron uptake and translocation by macrocystis pyrifera  

SciTech Connect

Parameters of iron uptake have been determined for blade tissue of Macrocystis pyrifera (L.) C. Ag. These include the effects of iron concentration, light, various inhibitors, and blade type. All experiments were conducted in the defined artificial seawater Aquil. Iron uptake is light independent, energy dependent, and dependent on the reduction from Fe/sup 3+/ to Fe/sup 2+/. Iron is concentrated in the sieve tube exudate; exudate analysis revealed the presence of other micronutrients. Iron and other micronutrient translocation is discussed.

Manley, S.L.

1981-10-01

354

[Clinical use of parenteral preparations of iron].  

PubMed

The article contains an analytical review of medical literature concerning the use of parenteral preparations of iron in clinical practice. In recent years new effective and safe intravenous preparations of iron have come to be used in medical practice, with formulae developed to calculate a general bodily iron deficiency, ways for and doses of their administration. Indications for administration of intravenous preparations of iron have now been extended in a well-founded manner to include a wider variety of cases. In the present review, modern status of use of intravenous preparations of iron are discussed together with prospects of their employment in future. PMID:12669535

Vydyborets', S V

2002-01-01

355

Iron and acetaminophen a fatal combination?  

PubMed

Intentional iron overdose in adults is uncommon. Clinical consequences are variable and depend on the quantity of iron ingested and the delay to treatment. Severe iron overdose can lead to multi-organ failure and acute hepatic necrosis. Here, we report three cases of polypharmacy overdose including iron resulting in acute liver failure. Despite maximum supportive care including liver transplantation in two cases, all patients died. Iron poisoning may have an additive toxic effect in drug-induced acute liver failure and worsen outcome. PMID:21883506

Audimoolam, Vinod K; Wendon, Julia; Bernal, William; Heaton, Nigel; O'Grady, John; Auzinger, Georg

2011-10-01

356

Chemical classification of iron meteorites. XI - Multielement studies of 38 new irons and the high abundance of ungrouped irons from Antarctica  

Microsoft Academic Search

Concentrations of 14 elements in the metal of 38 iron meteorites and a pallasite are reported. Three samples are paired with previously classified irons, raising the number of well-classified, independent iron meteorites to 598. Several of the new irons are from Antarctica. Of 24 independent irons from Antarctica, eight are ungrouped, a much higher fraction than that among all classified

J. T. Wasson; Xinwei Ouyang; Jianmin Wang; Jerde Eric

1989-01-01

357

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

PubMed

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

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

2007-01-01

358

Adipocyte iron regulates adiponectin and insulin sensitivity  

PubMed Central

Iron overload is associated with increased diabetes risk. We therefore investigated the effect of iron on adiponectin, an insulin-sensitizing adipokine that is decreased in diabetic patients. In humans, normal-range serum ferritin levels were inversely associated with adiponectin, independent of inflammation. Ferritin was increased and adiponectin was decreased in type 2 diabetic and in obese diabetic subjects compared with those in equally obese individuals without metabolic syndrome. Mice fed a high-iron diet and cultured adipocytes treated with iron exhibited decreased adiponectin mRNA and protein. We found that iron negatively regulated adiponectin transcription via FOXO1-mediated repression. Further, loss of the adipocyte iron export channel, ferroportin, in mice resulted in adipocyte iron loading, decreased adiponectin, and insulin resistance. Conversely, organismal iron overload and increased adipocyte ferroportin expression because of hemochromatosis are associated with decreased adipocyte iron, increased adiponectin, improved glucose tolerance, and increased insulin sensitivity. Phlebotomy of humans with impaired glucose tolerance and ferritin values in the highest quartile of normal increased adiponectin and improved glucose tolerance. These findings demonstrate a causal role for iron as a risk factor for metabolic syndrome and a role for adipocytes in modulating metabolism through adiponectin in response to iron stores.

Gabrielsen, J. Scott; Gao, Yan; Simcox, Judith A.; Huang, Jingyu; Thorup, David; Jones, Deborah; Cooksey, Robert C.; Gabrielsen, David; Adams, Ted D.; Hunt, Steven C.; Hopkins, Paul N.; Cefalu, William T.; McClain, Donald A.

2012-01-01

359

Cellular Iron Distribution in Bacillus anthracis  

PubMed Central

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.

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

2012-01-01

360

Ferric Iron Reduction by Acidophilic Heterotrophic Bacteria  

PubMed Central

Fifty mesophilic and five moderately thermophilic strains of acidophilic heterotrophic bacteria were tested for the ability to reduce ferric iron in liquid and solid media under aerobic conditions; about 40% of the mesophiles (but none of the moderate thermophiles) displayed at least some capacity to reduce iron. Both rates and extents of ferric iron reduction were highly strain dependent. No acidophilic heterotroph reduced nitrate or sulfate, and (limited) reduction of manganese(IV) was noted in only one strain (Acidiphilium facilis), an acidophile which did not reduce iron. Insoluble forms of ferric iron, both amorphous and crystalline, were reduced, as well as soluble iron. There was evidence that, in at least some acidophilic heterotrophs, iron reduction was enzymically mediated and that ferric iron could act as a terminal electron acceptor. In anaerobically incubated cultures, bacterial biomass increased with increasing concentrations of ferric but not ferrous iron. Mixed cultures of Thiobacillus ferrooxidans or Leptospirillum ferrooxidans and an acidophilic heterotroph (SJH) produced sequences of iron cycling in ferrous iron-glucose media.

Johnson, D. Barrie; McGinness, Stephen

1991-01-01

361

Wetting of iron aluminide alloys by Ag, Au, and Cu 1  

Microsoft Academic Search

Because successful integration of alloys into engineering structures often relies on joining technologies this study was done to learn about behavior relevant to brazing of iron aluminide alloys. Brazing processes are largely controlled by the wetting phenomenon, i.e. how well a liquid spreads over the surface of a solid. These experiments involved melting pure silver, copper and gold on the

Michael L. Santella; Amber B. Patterson

1998-01-01

362

Vintage structure dynamics and climate change policies: the case of US iron and steel  

Microsoft Academic Search

The US iron and steel industry consists of two main sectors—integrated firms producing outputs predominantly from virgin materials and fossil fuels, and electric arc furnaces operating mainly on scrap and electricity. Capacity and market shares of the former have declined for more than three decades, leading to reductions in energy use and emissions as the existing capital stock is retired.

Matthias Ruth; Anthony Amato

2002-01-01

363

POLLUTION EFFECTS OF ABNORMAL OPERATIONS IN IRON AND STEEL MAKING. VOLUME 1. TECHNICAL REPORT  

EPA Science Inventory

The report is the first 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, ge...

364

A generalized ionic approach to the epitaxial growth of yttrium iron garnet films in molten solutions  

Microsoft Academic Search

An ionic approach to the liquid-phase-epitaxy (LPE) growth of yttrium iron garnet (YIG) films suitable for microwave signal processing and other integrated electronic or magnetic applications has been developed. By extending Giess' theory and by accounting for the conspicuous amount of previous published data, the proposed model figures out a unified description of the solubility characteristics of the YIG system.

P. De Gasperis; R. Marcelli

1987-01-01

365

Comparative analysis of RBC membrane fatty acids, proteins and glycophorin in patients with heterozygous beta thalassemia and iron deficiency anemia  

Microsoft Academic Search

Membrane lipid and protein composition was compared in erythrocytes from iron deficiency anemia (IDA) and heterozygous beta\\u000a thalassemia patients. The study was planned to correlate the influence of iron deficiency with the intrinsic defect of the\\u000a heterozygous condition on the membrane structural integrity as well as to investigate whether there are differences in membrane\\u000a changes between the two conditions. Results

S. P. Sanghani; V. A. Haldankar

2006-01-01

366

Iron requirements of infants and toddlers.  

PubMed

Iron deficiency (ID) is the most common micronutrient deficiency worldwide and young children are a special risk group because their rapid growth leads to high iron requirements. Risk factors associated with a higher prevalence of ID anemia (IDA) include low birth weight, high cow's-milk intake, low intake of iron-rich complementary foods, low socioeconomic status, and immigrant status. The aim of this position paper was to review the field and provide recommendations regarding iron requirements in infants and toddlers, including those of moderately or marginally low birth weight. There is no evidence that iron supplementation of pregnant women improves iron status in their offspring in a European setting. Delayed cord clamping reduces the risk of ID. There is insufficient evidence to support general iron supplementation of healthy European infants and toddlers of normal birth weight. Formula-fed infants up to 6 months of age should receive iron-fortified infant formula, with an iron content of 4 to 8 mg/L (0.6-1.2 mg(-1) · kg(-1) · day(-1)). Marginally low-birth-weight infants (2000-2500 g) should receive iron supplements of 1-2 mg(-1) · kg(-1) · day(-1). Follow-on formulas should be iron-fortified; however, there is not enough evidence to determine the optimal iron concentration in follow-on formula. From the age of 6 months, all infants and toddlers should receive iron-rich (complementary) foods, including meat products and/or iron-fortified foods. Unmodified cow's milk should not be fed as the main milk drink to infants before the age of 12 months and intake should be limited to <500 mL/day in toddlers. It is important to ensure that this dietary advice reaches high-risk groups such as socioeconomically disadvantaged families and immigrant families. PMID:24135983

Domellöf, Magnus; Braegger, Christian; Campoy, Cristina; Colomb, Virginie; Decsi, Tamas; Fewtrell, Mary; Hojsak, Iva; Mihatsch, Walter; Molgaard, Christian; Shamir, Raanan; Turck, Dominique; van Goudoever, Johannes

2014-01-01

367

EfeO-cupredoxins: major new members of the cupredoxin superfamily with roles in bacterial iron transport  

Microsoft Academic Search

The EfeUOB system of Escherichia coli is a tripartite, low pH, ferrous iron transporter. It resembles the high-affinity iron transporter (Ftr1p-Fet3p) of yeast\\u000a in that EfeU is homologous to Ftr1p, an integral-membrane iron-permease. However, EfeUOB lacks an equivalent of the Fet3p\\u000a component—the multicopper oxidase with three cupredoxin-like domains. EfeO and EfeB are periplasmic but their precise roles\\u000a are unclear. EfeO

Mohan B. Rajasekaran; Sanjay Nilapwar; Simon C. Andrews; Kimberly A. Watson

2010-01-01

368

Iron plaque formation and morphoanatomy of roots from species of restinga subjected to excess iron.  

PubMed

The restingas, a sandy coastal plain ecosystem of Brazil, have received an additional amount of iron due to the activity of mining industries. The present study aims to characterize morphoanatomically and histochemically the iron plaque formation on roots of Ipomoea pes-caprae L. and Canavalia rosea DC, cultivated in hydroponic solution with and without excess iron. The iron plaque formation as well as changes in the external morphology of the lateral roots of both species were observed after the subjection to excess iron. Changes in the nutrient uptake, and in the organization and form of the pericycle and cortex cells were observed for both species. Scanning electron microscopy showed evident iron plaques on the whole surface of the root. The iron was histolocalized in all root tissues of both species. The species of restinga studied here formed iron plaque in their roots when exposed to excess of this element, which may compromise their development in environments polluted by particulated iron. PMID:22169228

Siqueira-Silva, Advanio Inácio; da Silva, Luzimar Campos; Azevedo, Aristéa Alves; Oliva, Marco Antonio

2012-04-01

369

Tissue iron, copper and zinc levels in offspring of iron-sufficient and iron-deficient rats.  

PubMed

To study the effects of iron nutriture on tissue iron, copper and zinc contents, we fed iron-deficient or control diets to pregnant rats and their offspring. Pups were weaned to the same or opposite diet as that fed to their dams, yielding four groups: control-control (CC), control-deficient (CD), deficient-control (DC) and deficient-deficient (DD). Offspring were killed at 2, 21, 30, 60 and 90 days of age. Iron deficiency, induced by feeding a 5 ppm iron diet to the dam and/or to the weanlings, resulted in impaired body growth, lower hemoglobin and hematocrit levels and reduced iron levels in liver, spleen and kidney of the offspring. Two-day-old iron-deficient pups had hepatic copper levels 1.5- fold higher than control pups. By the end of the suckling period, hepatic copper levels in iron-deficient pups were 3-fold greater than those of control pups. Hepatic copper concentration in control-fed rats (CC and DC) declined with maturation. In deficient rats (CD and DD), this normal decrease in hepatic copper did not occur and in CD rats, there was a progressive accumulation of copper in the liver. Renal zinc concentrations were lower in CD and DD than in control-fed animals at 60 and 90 days of age. These interactions among iron, copper and zinc may assume clinical importance since iron deficiency is a common nutritional problem. PMID:7463170

Sherman, A R; Tissue, N T

1981-02-01

370

Magnetic frustration and iron-vacancy ordering in iron chalcogenide  

NASA Astrophysics Data System (ADS)

We study the spin- and vacancy-ordered states in 122 iron chalcogenides (A1-yFe2-xSe2) by inspecting the magnetic ground states of a J1-J2-J3 model on different vacancy-ordered lattices observed/conjectured in these compounds. A highly frustrated J1-J2-J3 model was first applied to the study of magnetism in FeTe and was reported to explain the inelastic neutron-scattering data qualitatively. We find that the vacancy-ordered states are generally energetically favored for their reduction of magnetic frustration inherent to the spin-exchange model and, especially, that the 245 vacancy-spin-ordered state minimizes the magnetic exchange energy among all known vacancy-ordered states, in line with the fact that it has the highest vacancy-ordering phase transition temperature and the largest ordered moment in all iron-based superconductors. Thus, our study provides an electronic perspective for understanding the various vacancy orderings in these compounds. Then we focus on the experimentally well-studied 245 state and calculate the spin-wave spectrum and dynamic spin susceptibility. Finding that the key features of these calculated quantities are consistent with a recent inelastic neutron-scattering experiment, we conclude that we have obtained a qualitative local spin model for the 245 state. We also discuss the possibility of a unified local-moment description for all iron chalcogenides based on our result.

Fang, Chen; Xu, Bao; Dai, Pengcheng; Xiang, Tao; Hu, Jiangping

2012-04-01

371

[Growth characteristics and control of iron bacteria on cast iron in drinking water distribution systems].  

PubMed

This study investigated the growth characteristics of iron bacteria on cast iron and relationship between suspended and attached iron bacteria. The steady-state growth of iron bacteria would need 12 d and iron bacteria level in effluents increased 1 lg. Hydraulics influence on iron bacteria level and detachment rate of steady-state attached iron bacteria was not significant. But it could affect the time of attached iron bacteria on cast-iron coupons reaching to steady state. When the chlorine residual was 0.3 mg/L, the iron bacteria growth could be controlled effectively and suspended and attached iron bacteria levels both decreased 1 lg. When the chlorine residual was more than 1.0 mg/L, it could not inactivate the iron bacteria of internal corrosion scale yet. There was little effect on inhibiting the iron bacteria growth that the chlorine residual was 0.05 mg/L in drinking water quality standard of China. The iron bacteria on coupons reached to steady state without disinfectant and then increased the chlorine residual to 1.25 mg/L, the attached iron bacteria level could decrease 2 lg to 3 lg. Under steady-state, the suspended iron bacteria levels were linearly dependent on the attached iron bacteria. The control of iron bacteria in drinking water distribution systems was advanced: maintaining the chlorine residual (0.3 mg/L), flushing the pipeline with high dosage disinfectant, adopting corrosion-resistant pipe materials and renovating the old pipe loop. PMID:20063743

Wang, Yang; Zhang, Xiao-Jian; Chen, Yu-Qiao; Lu, Pin-Pin; Chen, Chao

2009-11-01

372

Iron and anemia in human biology: a review of mechanisms  

Microsoft Academic Search

The biology of iron in relation to anemia is best understood by a review of the iron cycle, since the majority of iron for\\u000a erythropoiesis is provided by iron recovered from senescent erythrocytes. In iron-deficiency anemia, storage iron declines\\u000a until iron delivery to the bone marrow is insufficient for erythropoiesis. This can be monitored with clinical indicators,\\u000a beginning with low

Garry J. Handelman; Nathan W. Levin

2008-01-01

373

Integration Update.  

ERIC Educational Resources Information Center

In this update of the integration efforts of the Riverside Unified School District, it is shown that the district continues to be committed to the integration of the staff. It is also committed to search for minority heritage staff. Along with staffing changes, there have been major program developments such as finding and using ethnic oriented…

Berry, Ray

374

Integrated care requires integrated supervision  

PubMed Central

Introduction Given recent developments in integrated care, it is becoming increasingly important for the Dutch Health Care Inspectorate to direct its supervision in a way that may help speed up the implementation of integrated care. Description of care practice Since the implementation of integrated care for chronic patients is facing obstacles, alternative methods are required to ensure that the implementation process does not run into any delays. By applying a risk-based approach to integrated care providers, the Inspectorate can analyse the care providers' performance by means of quality indicators and rank them. In order to be effective, appropriated supervision arrangements will be applied to the care providers of integrated care. Discussion With a ranking model transparency will be improved and this may encourage integrated care providers to strive for greater quality due to the competition inherent in the system. Supervision based on advice and encouragement might be helpful in the implementation of integrated care. Conclusion Integrated care also requires integrated supervision, which means the Inspectorate may have to reconsider its working methods and the composition of its inspection teams.

Ketelaars, Corry A.J

2011-01-01

375

Synthesis and Characterization of Stable Iron–Iron Oxide Core–Shell Nanoclusters for Environmental Applications  

SciTech Connect

Iron–iron oxide core–shell nanoclusters are of great interest due to their potential applications as a remedy for environmental contamination. We report the room-temperature synthesis of core–shell iron–iron oxide nanoclusters using our novel cluster deposition system. Various types of measurements such as Transmission Electron Microscopy, X-ray Diffraction, X-ray Photon Spectroscopy, and Electron Energy Loss Spectroscopy are conducted in characterizing nanoclusters. Stable, monodispersive iron–iron oxide core–shell nanocrystals are identified.

Antony, Jiji; Qiang, You; Baer, Donald R.; Wang, Chong M.

2006-02-01

376

Integrated care  

PubMed Central

Abstract The WHO European Office for Integrated Health Care Services in Barcelona is an integral part of the World Health Organizations' Regional Office for Europe. The main purpose of the Barcelona office is within the integration of services to encourage and facilitate changes in health care services in order to promote health and improve management and patient satisfaction by working for quality, accessibility, cost-effectiveness and participation. This position paper outlines the need for Integrated Care from a European perspective, provides a theoretical framework for the meaning of Integrated Care and its strategies and summarizes the programmes of the office that will support countries in the WHO European Region to improve health services.

Grone, Oliver; Garcia-Barbero, Mila

2001-01-01

377

Theoretical analysis of iron-bore superconducting undulators  

SciTech Connect

The unavoidable undulator field errors due to machining tolerances of the yokes lead to a reduction of the gain in comparison with the case computed with an ideally perfect undulator. We describe a mathematical model of errors in iron-dominated micro-undulators introduced by manufacturing tolerances. Explicit expressions for the perturbation fields are derived. We use these fields to calculate the first, second and phase integrals describing the effects on the electron trajectory. We conclude that the intrinsic tolerances achievable with wire electric discharge machining do not significantly affect the performance of the Accelerator Test Facility free-electron laser. 9 refs., 6 figs.

Ben-Zvi, I.; Fernow, R.; Gallardo, J.; Ingold, G.; Sampson, W.; Woodle, M.

1991-01-01

378

Iron Acquisition and Regulation in Campylobacter jejuni  

PubMed Central

Iron affects the physiology of bacteria in two different ways: as a micronutrient for bacterial growth and as a catalyst for the formation of hydroxyl radicals. In this study, we used DNA microarrays to identify the C. jejuni genes that have their transcript abundance affected by iron availability. The transcript levels of 647 genes were affected after the addition of iron to iron-limited C. jejuni cells. Several classes of affected genes were revealed within 15 min, including immediate-early response genes as well as those specific to iron acquisition and metabolism. In contrast, only 208 genes were differentially expressed during steady-state experiments comparing iron-rich and iron-limited growth conditions. As expected, genes annotated as being involved in either iron acquisition or oxidative stress defense were downregulated during both time course and steady-state experiments, while genes encoding proteins involved in energy metabolism were upregulated. Because the level of protein glycosylation increased with iron limitation, iron may modulate the level of C. jejuni virulence by affecting the degree of protein glycosylation. Since iron homeostasis has been shown to be Fur regulated in C. jejuni, an isogenic fur mutant was used to define the Fur regulon by transcriptome profiling. A total of 53 genes were Fur regulated, including many genes not previously associated with Fur regulation. A putative Fur binding consensus sequence was identified in the promoter region of most iron-repressed and Fur-regulated genes. Interestingly, a fur mutant was found to be significantly affected in its ability to colonize the gastrointestinal tract of chicks, highlighting the importance of iron homeostasis in vivo. Directed mutagenesis of other genes identified by the microarray analyses allowed the characterization of the ferric enterobactin receptor, previously named CfrA. Chick colonization assays indicated that mutants defective in enterobactin-mediated iron acquisition were unable to colonize the gastrointestinal tract. In addition, a mutation in a receptor (Cj0178) for an uncharacterized iron source also resulted in reduced colonization potential. Overall, this work documents the complex response of C. jejuni to iron availability, describes the genetic network between the Fur and iron regulons, and provides insight regarding the role of iron in C. jejuni colonization in vivo.

Palyada, Kiran; Threadgill, Deborah; Stintzi, Alain

2004-01-01

379

Iron storage disease in tapirs.  

PubMed

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

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

2006-03-01

380

Modelling iron interaction with organic matter  

NASA Astrophysics Data System (ADS)

The understanding of iron speciation and its various biogeochemical interactions remains an important issue in environmental science. Indeed, available Fe is an essential element for numerous biotas, including phytoplankton. In addition colloidal iron oxides are known to play an important role on the mobility and bioavailability of various contaminants, through their reactivity, their high surface area and ubiquity at the earth's surface. Recent modelling efforts have provided generic Fe binding parameters towards natural organic matter analogues. Nevertheless these models are calibrated with a limited database and do not take explicitly into account iron oxides. Mixture of insolubilized humic acid was reacted with solutions of known total iron concentration in a 0.1 KNO3 background electrolyte. The pH of the experiments ranged from 2 to 5.5. The combination of spectroscopic and chemical analysis provided data that is necessary to constrain the modelling approach. The binding of iron is strongly pH dependent and controlled by iron amorphous oxides solubility when high concentrations of iron are used. At much lower concentrations the redox properties of organic matter are controlling the speciation of iron. This new experimental data set is analyzed with the NICA- Donnan approach. New parameters constrained by spectroscopic data are proposed to describe the behaviour of iron in natural systems. These new findings are compared to field measurements in organic and iron rich tropical soil solutions and rivers.

Benedetti, M. F.; Weber, T.; Allard, T.

2006-12-01

381

Current approach to iron chelation in children.  

PubMed

Transfusion-dependent children, mostly with thalassaemia major, but also and occasionally to a more significant degree, with inherited bone marrow failures, can develop severe iron overload in early life. Moreover, chronic conditions associated with ineffective erythropoiesis, such as non-transfusion-dependent thalassaemia (NTDT), may lead to iron overload through increased gut absorption of iron starting in childhood. Currently, the goal of iron chelation has shifted from treating iron overload to preventing iron accumulation and iron-induced end-organ complications, in order to achieve a normal pattern of complication-free survival and of quality of life. New chelation options increase the likelihood of achieving these goals. Timely initiation, close monitoring and continuous adjustment are the cornerstones of optimal chelation therapy in children, who have a higher transfusional requirements compared to adults in order to reach haemoglobin levels adequate for normal growth and development. Despite increased knowledge, there are still uncertainties about the level of body iron at which iron chelation therapy should be started and about the appropriate degree of iron stores' depletion. PMID:24646011

Aydinok, Yesim; Kattamis, Antonis; Viprakasit, Vip

2014-06-01

382

F-8 Iron Bird Cockpit  

NASA Technical Reports Server (NTRS)

The F-8 DFBW (Digital-Fly-By-Wire) simulator used an 'Iron-Bird' for its cockpit. It was used from 1971 to 1986. The F-8 DFBW simulator was used in the development, testing, and validation of an all digital flight-control system installed in the F-8 aircraft that replaced the normal mechanical/hydraulic controls. Many military and commercial aircraft have digital flight control systems based on the technologies developed at NASA Dryden.

1975-01-01

383

Magnetic Properties of Iron Clusters  

Microsoft Academic Search

In this dissertation we present results of experiments designed to map out the magnetic behavior of free iron clusters. We report a decrease in the magnetic moment from a high of 3.06mu_{B} \\/atom for 70 atom clusters down to the bulk value of 2.2mu_{B} for clusters of 700 or more atoms. The clusters are superparamagnetic for vibrational temperatures above 248K.

Joseph Girard Louderback IV

1995-01-01

384

Reactive iron in marine sediments  

Microsoft Academic Search

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

Donald E. Canfield

1989-01-01

385

Southern Ocean natural iron fertilization  

Microsoft Academic Search

Modeling and Synthesis of Southern Ocean Natural Iron Fertilization; Woods Hole, Massachusetts, 27--29 June 2011; For many years a major paradox in ocean science was the existence of regions where the major nutrients are present in nonlimiting concentrations yet phytoplankton biomass is low. Pioneering experiments in the 1990s firmly established that the likely cause of this high-nutrient, low-chlorophyll condition is

Matt Charette; Richard Sanders; Meng Zhou

2011-01-01

386

Albumin holograms with iron ions  

NASA Astrophysics Data System (ADS)

The preparation of photosensitive films of quail albumen (protein), applying as oxidizing agent, green iron ammonium citrate. Exposed to a He-Cd laser, ? = 442nm, transmission holograms were recorded. We obtained the diffraction patterns reconstructed with He-Ne laser, ?=632.8nm and measuring diffraction efficiencies for first order as a function of exposure energy. Holographic gratings made with these materials exhibit behaviour of self develop. We analyse the experimental results.

Ordóñez-Padilla, M. J.; Olivares-Pérez, A.; Ortiz-Gutiérrez, M.; Juárez-Ramírez, J. C.

2014-02-01

387

Intravenous iron in inflammatory bowel disease  

PubMed Central

The prevalence of anemia across studies on patients with inflammatory bowel disease (IBD) is high (30%). Both iron deficiency (ID) and anemia of chronic disease contribute most to the development of anemia in IBD. The prevalence of ID is even higher (45%). Anemia and ID negatively impact the patient’s quality of life. Therefore, together with an adequate control of disease activity, iron replacement therapy should start as soon as anemia or ID is detected to attain a normal hemoglobin (Hb) and iron status. Many patients will respond to oral iron, but compliance may be poor, whereas intravenous (IV) compounds are safe, provide a faster Hb increase and iron store repletion, and presents a lower rate of treatment discontinuation. Absolute indications for IV iron treatment should include severe anemia, intolerance or inappropriate response to oral iron, severe intestinal disease activity, or use of an erythropoietic stimulating agent. Four different products are principally used in clinical practice, which differ in their pharmacokinetic properties and safety profiles: iron gluconate and iron sucrose (lower single doses), and iron dextran and ferric carboxymaltose (higher single doses). After the initial resolution of anemia and the repletion of iron stores, the patient’s hematological and iron parameters should be carefully and periodically monitored, and maintenance iron treatment should be provided as required. New IV preparations that allow for giving 1000-1500 mg in a single session, thus facilitating patient management, provide an excellent tool to prevent or treat anemia and ID in this patient population, which in turn avoids allogeneic blood transfusion and improves their quality of life.

Munoz, Manuel; Gomez-Ramirez, Susana; Garcia-Erce, Jose Antonio

2009-01-01

388

The molecular biology of human iron metabolism.  

PubMed

Iron is one of the most important nonorganic substances that make life possible. Iron plays major roles in oxygen transport (eg, hemoglobin; -67% of total body iron [TBI]), short-term oxygen storage (eg, myoglobin; -3.5% of TBI), and energy generation (eg, cytochromes; -3% of TBI). Iron also serves vital roles in various nonheme-containing enzymes (-2% of TBI). Figure 1 lists heme-containing and nonheme iron-containing proteins. TBI is controlled by the rate of iron absorption; there are no physiologic mechanisms to excrete excess iron. Iron deficiency has many adverse consequences, including anemia, and in children, behavioral and learning disorders. Iron excess is toxic to the body, harming the heart, liver, skin, pancreatic islet beta cells, bones, joints, and pituitary gland. Maintaining proper iron balance is essential for maintaining homeostasis and health. TBI in adults normally ranges between 3.5 and 5.0 g. A total of 75% of TBI is functional, and 25% is stored within cells as ferritin or hemosiderin. Ferritin contains 24 subunits of light chains (L chains; 19.7 kDa) and heavy chains (H chains; 21.1 kDa). The L chains are encoded on chromosome 19q13.33 and are 175 amino acids long. The H chains are encoded on chromosome 11q1 and are 183 amino acids long. Each ferritin molecule can contain as many as approximately 4500 ferric ions. Because the major role of iron is in hemoglobin synthesis, this review will focus on iron, iron transport, and hematopoiesis. PMID:24868988

Winter, William E; Bazydlo, Lindsay A L; Harris, Neil S

2014-01-01

389

Iron-Tolerant Cyanobacteria: Ecophysiology and Fingerprinting  

NASA Technical Reports Server (NTRS)

Although the iron-dependent physiology of marine and freshwater cyanobacterial strains has been the focus of extensive study, very few studies dedicated to the physiology and diversity of cyanobacteria inhabiting iron-depositing hot springs have been conducted. One of the few studies that have been conducted [B. Pierson, 1999] found that cyanobacterial members of iron depositing bacterial mat communities might increase the rate of iron oxidation in situ and that ferrous iron concentrations up to 1 mM significantly stimulated light dependent consumption of bicarbonate, suggesting a specific role for elevated iron in photosynthesis of cyanobacteria inhabiting iron-depositing hot springs. Our recent studies pertaining to the diversity and physiology of cyanobacteria populating iron-depositing hot springs in Great Yellowstone area (Western USA) indicated a number of different isolates exhibiting elevated tolerance to Fe(3+) (up to 1 mM). Moreover, stimulation of growth was observed with increased Fe(3+) (0.02-0.4 mM). Molecular fingerprinting of unialgal isolates revealed a new cyanobacterial genus and species Chroogloeocystis siderophila, an unicellular cyanobacterium with significant EPS sheath harboring colloidal Fe(3+) from iron enriched media. Our preliminary data suggest that some filamentous species of iron-tolerant cyanobacteria are capable of exocytosis of iron precipitated in cytoplasm. Prior to 2.4 Ga global oceans were likely significantly enriched in soluble iron [Lindsay et al, 2003], conditions which are not conducive to growth of most contemporary oxygenic cyanobacteria. Thus, iron-tolerant CB may have played important physiological and evolutionary roles in Earths history.

Brown, I. I.; Mummey, D.; Lindsey, J.; McKay, D. S.

2006-01-01

390

Iron overload and glucose metabolism in subjects with ?-thalassaemia major: an overview.  

PubMed

Thalassaemia is one of the most common genetic disorders caused by a reduction of the globin chains leading to chronic haemolytic anaemia from birth. The mainstay of treatment is blood transfusion to maintain adequate levels of the haemoglobin. Iron overload in ?-thalassaemia major patients is secondary to multiple blood transfusions and increased iron absorption. Excess iron potentially catalyzes free-radicals generation and impairment in cellular function and integrity. Extensive iron-induced injury develops in the heart, liver, pancreas and endocrine system. Pancreatic iron loading in thalassaemia major patients begins at early childhood, and the prevalence of diabetes mellitus (DM) ranges from 6.4% to 14.1% in cross-sectional studies. Both insulin resistance and decreased insulin secretion contribute to DM in thalassaemia major patients. This has been shown by oral glucose tolerance test, euglycemic insulin clamp, homeostatic model assessment, intravenous glucose tolerance test and continuous glucose monitoring system. The prevalence of DM in thalassaemia has been shown to correlate with serum ferritin concentration, hepatitis C infection, and pancreatic and cardiac iron measured by imaging techniques. Therefore the incidence of disturbed glucose homeostasis depends on adherence to chelation treatment, the adequacy of the dosage, the chemical properties of the chelating agent and the prevention of liver infections. PMID:23687960

De Sanctis, Vincenzo; Soliman, Ashraf; Yassin, Mohamed

2013-07-01

391

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

PubMed

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

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

2005-12-01

392

Synthesis and Thermodynamic Evaluation of Mixed Hexadentate Linear Iron Chelators Containing Hydroxypyridinone and Terephthalamide Units1  

PubMed Central

A series of new linear iron chelators containing hydroxypyridinone and terephthalamide moieties has been prepared. All are hexadentate ligands composed of a systematically varied combination of me-3,2-hydroxypyridinone and 2,3-dihydroxyterephthalamide binding units; most are based on a spermidine scaffold but one incorporates the bifunctional 2,3-dihydroxyterephthalamide unit as an integral part of the backbone. Protonation and ferric iron complex formation constants have been determined from solution thermodynamic studies giving log ?110 values of 25.7, 30.7, 36.3, 43.8, and 45.0 respectively. The ferric complexes display reversible reduction potentials from ?276 mV to ?1032 mV (measured relative to the normal hydrogen electrode NHE) in alkaline solution. The incremental replacement of hydroxypyridinone units by terephthalamide binding groups progressively reduces the ligand acidity, markedly increases the iron-chelate stability, and improves the selectivity for ferric ion over ferrous ion. While the majority of iron chelators forming very stable ferric complexes are based on a tripodal backbone such as TREN, the ferric 5-LIO(TAMmeg)2(TAM) complex, despite its non-tripodal scaffold, is one of the most stable iron complexes yet reported. Moreover, the high affinity for ferric ion of the discussed linear ligands strongly correlates with their ability to remove iron in vivo.

Abergel, Rebecca J.; Raymond, Kenneth N.

2011-01-01

393

Iron core in the sun?  

NASA Astrophysics Data System (ADS)

A suggestion has been made that the sun may have a central core composed of iron (New Scientist, June 23, 1983). This suggestion is the latest attempt to force a fit to theoretical models of the sun's internal temperature structure. That the sun does not fit well enough as a model for compositional origin of the rest of the solar system is evidenced in its apparent deficiency in the production of neutrinos. Measurements on the earth to detect the emission of solar neutrinos are typically low by as much as a factor of 3. If the core of the sun were to be composed of a sufficiently stable element, such as the form of iron that would exist at 14 million K, the production of neutrinos would be about what is observed. The result of the calculations of Carl Rouse is that the sun could have a core radius of about 5% of the total, with a density of about 1.6×105 kg m-3. This core would be consistent with the properties of an iron plasma, instead of hydrogen and helium nuclei. In the modeling procedure one could adjust the sun's temperature to a value lowered by about 1 million K and have a lowered neutrino flux as well.

Bell, Peter M.

394

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

PubMed

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

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

2013-12-01

395

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

PubMed Central

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.

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

2010-01-01

396

Escherichia coli RIC is able to donate iron to iron-sulfur clusters.  

PubMed

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

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

2014-01-01

397

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

PubMed Central

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.

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

2014-01-01

398

Iron fortification and iron supplementation are cost-effective interventions to reduce iron deficiency in four subregions of the world  

Microsoft Academic Search

Iron deficiency is the most common and widespread nutritional disorder in\\u000a the world, affecting millions of people in both nonindustrialized and\\u000a industrialized countries. We estimated the costs, effects, and\\u000a cost-effectiveness of iron supplementation and iron fortification\\u000a interventions in 4 regions of the world. The effects on population health\\u000a were arrived at by using a population model designed to estimate the

C. Knai; M. Sharan; R. M. P. M. Baltussen

2004-01-01

399

Spin-Lattice Dynamics Simulations of Ferromagnetic Iron  

NASA Astrophysics Data System (ADS)

We develop a Spin-Lattice Dynamics (SLD) simulation model for ferromagnetic iron where atoms are treated as classical particles with spins. The atoms interact via many-body forces as well as via spin-orientation-dependent forces of the Heisenberg form. The coupling between the lattice and the spin degrees of freedom is described by a coordinate-dependent exchange function. An algorithm for integrating the spin-lattice dynamics equations of motion is based on the 2nd order Suzuki-Trotter decomposition for the non-commuting Liouville evolution operators for atomic coordinates and spins. The notions of the spin thermostat and the spin temperature are introduced through a combined application of the Langevin spin dynamics and the fiuctuation-dissipation theorem. Several applications of the new method described in the paper illustrate the significant effect of the spin degrees of freedom on the dynamics of atomic motion in iron and iron-based alloys, and confirm that the Spin-Lattice Dynamics approach provides a viable framework for performing realistic large-scale simulations of magnetic materials.

Ma, Pui-Wai; Woo, C. H.; Dudarev, S. L.

2008-04-01

400

Structural basis for iron piracy by pathogenic Neisseria  

PubMed Central

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.

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

401

Structural basis for iron piracy by pathogenic Neisseria.  

PubMed

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

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

402

The development of precipitated iron catalysts with improved stability  

SciTech Connect

The goal of this program is to identify the chemical principles governing the deactivation of precipitated iron catalysts during Fischer-Tropsch synthesis and to use these chemical principles in the design of catalysts suitable for slurry reactors. This report covers testing an iron catalyst. During the last quarter, a new precipitated iron catalyst was prepared and tested in the slurry autoclave reactor at various conditions. This catalyst did not noticeably deactivate during 1250 hours of testing. This quarter, the test was extended to include performance evaluations at different conversion levels ranging from 35 to 88% at 265 and 275{degree}C. The conversion levels were varied by changing the feed rate. The catalytic performance at different conversion intervals was then integrated to approximately predict performance in a bubble column reactor. The run was shut down at the end of 1996 hours because of a 24-hour-power outage. When the power was back on, the run was restarted from room temperature. Catalytic performance during the first 300 hours after the restart-up was monitored. Overall product distributions are being tabulated as analytical laboratory data are obtained. 34 figs., 3 tabs.

Not Available

1990-01-01

403

Modelling Iron-Bentonite Interactions  

NASA Astrophysics Data System (ADS)

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.

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

2009-04-01

404

Iron management in end-stage renal disease  

Microsoft Academic Search

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

Steven Fishbane; John K. Maesaka

1997-01-01

405

Geochemistry of banded iron formation of Orissa, India  

Microsoft Academic Search

Major and trace element analyses of representative samples of various types of banded iron-formation and its various minerals, associated sediments, iron ores and volcanic tuff from different localities of Orissa, India, are presented in this paper. The Orissa banded iron-formation is classified as Precambrian banded iron formation and is similar to the oxide facies iron formation of Lake Superior type.

Tapan Majumder; K. L. Chakraborty; Auditeya Bhattacharyya

1982-01-01

406

The mechanochemical synthesis of thermoelectric material iron disilicide based  

Microsoft Academic Search

The iron disilicide is the cheapest thermoelectric material available for mass production of generators. The problem is one of low efficiency of iron disilicide. The efficiency can be imceased by means of doping of iron disilicide, thus making a composite material, and diminishing the grain size of iron disilicide ceramics. Mechanical alloying is the most convenient method of iron silicide

E. Yu. Belyaev; G. A. Suchkova; A. I. Ancharov; O. I. Lomovsky; V. I. Maly

2001-01-01

407

Mbosi: an anomalous iron with unique silicate inclusions  

Microsoft Academic Search

The Mbosi iron meteorite contains millimeter size silicate inclusions. Mbosi is an ungrouped iron with a Ge\\/Ga ratio >10, an anomalous property shared with the five-member IIF iron group, the Eagle Station pallasites and four other ungrouped irons. Neither the IIF group nor the four other ungrouped irons are known to have silicate inclusions. Chips from three Mbosi inclusions were

Edward J. Olsen; Robert N. Clayton; Toshiko K. Mayeda; Andrew M. Davis; Roy S. Clarke Jr.; John T. Wasson

1996-01-01

408

Iron-Deficient Diet: Effects in Rats and Humans.  

National Technical Information Service (NTIS)

Iron absorption in rats is increased by dietary iron deprivation. Erythropoiesis in the rat is unaffected by dietary iron deprivation that increases iron absorption by more than a factor of four. Iron absorption is not increased in rats bled of an amount ...

R. M. Kaufman S. Pollack W. H. Crosby

1966-01-01

409

Iron meteorites: Crystallization, thermal history, parent bodies, and origin  

Microsoft Academic Search

We review the crystallization of the iron meteorite chemical groups, the thermal history of the irons as revealed by the metallographic cooling rates, the ages of the iron meteorites and their relationships with other meteorite types, and the formation of the iron meteorite parent bodies. Within most iron meteorite groups, chemical trends are broadly consistent with fractional crystallization, implying that

J. I. Goldstein; E. R. D. Scott; N. L. Chabot

2009-01-01

410

Solid iron compressed up to 560 GPa.  

PubMed

Dynamic compression by multiple shocks is used to compress iron up to 560 GPa (5.6 Mbar), the highest solid-state pressure yet attained for iron in the laboratory. Extended x-ray absorption fine structure (EXAFS) spectroscopy offers simultaneous density, temperature, and local-structure measurements for the compressed iron. The data show that the close-packed structure of iron is stable up to 560 GPa, the temperature at peak compression is significantly higher than expected from pure compressive work, and the dynamic strength of iron is many times greater than the static strength based on lower pressure data. The results provide the first constraint on the melting line of iron above 400 GPa. PMID:23971582

Ping, Y; Coppari, F; Hicks, D G; Yaakobi, B; Fratanduono, D E; Hamel, S; Eggert, J H; Rygg, J R; Smith, R F; Swift, D C; Braun, D G; Boehly, T R; Collins, G W

2013-08-01

411

Interface Motion in Phase Transformations. Transformations in Iron and Iron-9 Percent Nickel Alloys.  

National Technical Information Service (NTIS)

Thermal arrest, hot stage microscopy and transmission electron microscopy techniques have been employed to study the transformations in low carbon iron and iron-9% nickel alloys. In continuous cooling experiments, both series of alloys transform at an ess...

R. H. Goodenow R. F. Hehemann

1965-01-01

412

Significance of Iron Isotope Mineral Fractionation in Pallasite and Iron Meteorites  

NASA Astrophysics Data System (ADS)

The iron isotope compositions of minerals from pallasites, iron meteorites, and of bulk chondrites are presented. The significance of these data regarding pallasite parent bodies and planetary mantle-core differentiation is then explored.

Poitrasson, F.; Levasseur, S.; Teutsch, N.

2004-03-01

413

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

Code of Federal Regulations, 2013 CFR

...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...

2013-10-01

414

Iron Deficiency and Obesity: The Contribution of Inflammation and Diminished Iron Absorption.  

National Technical Information Service (NTIS)

Poor iron status affects billions of people worldwide. The prevalence of obesity continues to rise in both developed and developing nations. An association between iron status and obesity has been described in children and adults. The mechanism explaining...

J. P. Karl J. P. McClung

2008-01-01

415

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

Code of Federal Regulations, 2010 CFR

...PIPELINE SAFETY TRANSPORTATION OF NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Requirements for Corrosion Control § 192.489 Remedial measures: Cast iron and ductile iron pipelines. (a) General graphitization....

2010-10-01

416

Surface modification of high temperature iron alloys  

DOEpatents

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.

Park, J.H.

1995-06-06

417

Adsorption of ammonia on multilayer iron phthalocyanine  

SciTech Connect

The adsorption of ammonia on multilayers of well-ordered, flat-lying iron phthalocyanine (FePc) molecules on a Au(111) support was investigated by x-ray photoelectron spectroscopy. We find that the electron-donating ammonia molecules coordinate to the metal centers of iron phthlalocyanine. The coordination of ammonia induces changes of the electronic structure of the iron phthalocyanine layer, which, in particular, lead to a modification of the FePc valence electron spin.

Isvoranu, Cristina; Knudsen, Jan; Ataman, Evren; Andersen, Jesper N.; Schnadt, Joachim [Division of Synchrotron Radiation Research, Department of Physics, Lund University, Box 118, 221 00 Lund (Sweden); Schulte, Karina [MAX-lab, Lund University, Box 118, 221 00 Lund (Sweden); Wang Bin; Bocquet, Marie-Laure [Laboratoire de chimie, Ecole normale superieure de Lyon, 46, Allee d'Italie, 69364 Lyon Cedex 07 (France)

2011-03-21

418

Thermodynamics applied to iron smelting techniques  

NASA Astrophysics Data System (ADS)

Thermodynamics allows us to understand the chemical reactions occurring inside an experimental archaeometallurgical shaft furnace for iron smelting. The production of an iron bloom, with the so-called direct process, is described in a daily pyrometallurgical cycle. The experiences suggest that, as higher and better blown furnaces were built for improving the production, different reactions have been involved and a new material, pig iron, has been obtained

Cavallini, Mauro

2013-12-01

419

Insulin resistance–associated hepatic iron overload  

Microsoft Academic Search

Background & Aims: Hepatic iron overload has been reported in various metabolic conditions, including the insulin-resistance syndrome (IRS) and nonalcoholic steatohepatitis (NASH). The aim of this study was to show that such hepatic iron overload is part of a unique and unrecognized entity. Methods: A total of 161 non–C282Y-homozygous patients with unexplained hepatic iron overload were included. We determined the

Michel-Henry Mendler; Bruno Turlin; Romain Moirand; Anne-Marie Jouanolle; Thierry Sapey; Dominique Guyader; Jean-Yves le Gall; Pierre Brissot; Véronique David; Yves Deugnier

1999-01-01

420

Iron dyshomeostasis in Parkinson’s disease  

Microsoft Academic Search

Owing to its ability to undergo one-electron reactions, iron transforms the mild oxidant hydrogen peroxide into hydroxyl radical,\\u000a one of the most reactive species in nature. Deleterious effects of iron accumulation are dramatically evidenced in several\\u000a neurodegenerative diseases. The work of Youdim and collaborators has been fundamental in describing the accumulation of iron\\u000a confined to the substantia nigra (SN) in

J. Salazar; N. Mena; M. T. Núñez

421

High toughness-high strength iron alloy  

NASA Technical Reports Server (NTRS)

An iron alloy is provided which exhibits strength and toughness characteristics at cryogenic temperatures. The alloy consists essentially of about 10 to 16 percent by weight nickel, about 0.1 to 1.0 percent by weight aluminum, and 0 to about 3 percent by weight copper, with the balance being essentially iron. The iron alloy is produced by a process which includes cold rolling at room temperature and subsequent heat treatment.

Stephens, J. R.; Witzke, W. R. (inventors)

1980-01-01

422

Directional Solidification of Nodular Cast Iron  

NASA Technical Reports Server (NTRS)

Cerium enhances formation of graphite nodules. Preliminary experiments in directional solidification of cast iron shows quantitative correlation of graphite microstructure with growth rate and thermal gradient, with sufficient spheroidizing element to form spheroidal graphite under proper thermal conditions. Experimental approach enables use of directional solidification to study solidification of spheriodal-graphite cast iron in low gravity. Possible to form new structural materials from nodular cast iron.

Curreri, P. A.; Stefanescu, D. M.; Hendrix, J. C.

1987-01-01

423

Reduction of double layered iron ore pellets  

Microsoft Academic Search

In the, present investigation an attempt has been made to study the reduction behaviour of double layer pellets consisting of a core of iron ore and a non-coking coal mixture within a shell of iron ore. The reduction tests were conducted under isothermal conditions in the temperature range 1000–1200°C. The variables (parameters) studied are reduction temperature, carbon\\/iron oxide ratio and

T. Sharma

1997-01-01

424

Iron oxyhydroxide colloids stabilized with polysaccharides  

Microsoft Academic Search

Neutralization of iron salts in aqueous solutions of ?-carrageenan and cellulose sulfate results in iron oxyhydroxide–polysaccharide\\u000a hybrid colloids with unusual pH stability up to pH 13. It is shown that both polysaccharides form a tight polymer layer surrounding\\u000a the inorganic particles, which in the case of ?-carrageenan is cross-linked by helical domains forming a self-assembled nanoreactor.\\u000a The stabilized iron oxyhydroxide

F. Jones; H. Cölfen; M. Antonietti

2000-01-01

425

Zinc inhibits nonheme iron bioavailability in humans  

Microsoft Academic Search

There is increasing concern about potential negative interactions in combined iron and zinc supplementation. The aim of the\\u000a present study was to determine the dose-response effect of zinc, given as a solution, on iron bioavailability. Twenty-two\\u000a healthy adult women were selected to participate in the study. Iron, with or without zinc was given as an aqueous solution\\u000a on d 1,2,14,

M. Olivares; F. Pizarro; M. Ruz

2007-01-01

426

The Iron Abundance of IOTA Herculis From Ultraviolet Iron Lines  

NASA Astrophysics Data System (ADS)

We have obtained (Adelman 1992, 1993, private comunication) coadded, high-resolution IUE spectra of Iota Herculis (B3 IV) in both short wavelength (SWP) and long wavelength (LWP) regions. The spectra span the ultraviolet spectrum from 110 - 300 nm and have a SNR of roughly 30 -50; they are described in Adelman et. al. (1993, ApJ 419, 276). Abundance indicators were 54 lines of Fe II and 26 lines of Fe III whose atomic parameters have been measured in the laboratory. LTE synthetic spectra for comparison with observations were produced with the Kurucz model atmosphere and spectral synthesis codes ATLAS9/SYNTHE (Kurucz 1979, ApJS 40,1; Kurucz and Avrett 1981, SAO Special Report 391). Model parameters were chosen from the literature: effective temperature = 17500 K, log g =3.75, v sin i= 11 km/s, and turbulent velocity = 0 km/s. (Peters and Polidan 1985, in IAU Symposium 111, ed. D. S. Hayes et al. (Dordrecht: Reidel), 417). We determined the equivalent widths of the chosen lines by fitting gaussian profiles to the lines and by measuring the equivalent widths of the gaussians. We derived abundances by fitting a straight line to a plot of observed equivalent widths vs. synthetic equivalent widths; we adjusted the iron abundance of the models until a slope of unity was achieved. The abundances derived from the different ionization stages are in agreement: Fe II lines indicate an iron abundance that is 34 +15/-10% the solar value([Fe/H]=-0.47 +0.16-0.15dex), while from Fe III lines we obtain 34 +/- 10% ([Fe/H]=-0.47 +0.11/-0.15 dex). A search of the literature suggests that no previous investigations of this star's iron abundance have found agreement between the different ionization stages. We thank Saul Adelman for his generous assistance, and the Faculty Research Fund Board of Wittenberg University for support of this research.

Grigsby, J.; Mulliss, C.; Baer, G.

1995-03-01

427

Integrated diagnostics  

NASA Technical Reports Server (NTRS)

Recently completed projects in which advanced diagnostic concepts were explored and/or demonstrated are summarized. The projects begin with the design of integrated diagnostics for the Army's new gas turbine engines, and advance to the application of integrated diagnostics to other aircraft subsystems. Finally, a recent project is discussed which ties together subsystem fault monitoring and diagnostics with a more complete picture of flight domain knowledge.

Hunthausen, Roger J.

1988-01-01

428

Selective-Area Micropatterning of Liquid-Phase Epitaxy-Grown Iron Garnet Films  

NASA Astrophysics Data System (ADS)

We investigated selective-area micropatterning of iron garnet film grown by liquid-phase epitaxy (LPE). This method of producing a flat-surface structure overcomes the disadvantages of geometrical grooves, which are formed by wet or dry etching, with a limited resolution due to underetching and nonplanar structure. Moreover, patterned iron garnet films grown by selective-area LPE have better single-crystal properties than films grown by selective-area sputter epitaxy deposition. Thus, this method offers new possibilities for the fabrication of integrated magnetooptic light switch arrays, magnetic waveguides and other magnetooptic devices.

Park, Jae-Hyuk; Cho, Jae-kyeong; Nishimura, Kazuhiro; Uchida, Hironaga; Inoue, Mitsuteru

2004-07-01

429

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

PubMed Central

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.

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

2013-01-01

430

Organic iron (III) complexing ligands during an iron enrichment experiment in the western subarctic North Pacific  

Microsoft Academic Search

Complexation of iron (III) with natural organic ligands was investigated during a mesoscale iron enrichment experiment in the western subarctic North Pacific (SEEDS II). After the iron infusions, ligand concentrations increased rapidly with subsequent decreases. While the increases of ligands might have been partly influenced by amorphous iron colloids formation (12–29%), most in-situ increases were attributable to the <200 kDa

Yoshiko Kondo; Shigenobu Takeda; Jun Nishioka; Hajime Obata; Ken Furuya; William Keith Johnson; C. S. Wong

2008-01-01

431

Iron-regulatory proteins limit hypoxia-inducible factor-2? expression in iron deficiency  

Microsoft Academic Search

Hypoxia stimulates erythropoiesis, the major iron-utilization pathway. We report the discovery of a conserved, functional iron-responsive element (IRE) in the 5? untranslated region of the messenger RNA encoding endothelial PAS domain protein-1, EPAS1 (also called hypoxia-inducible factor-2?, HIF2?). Via this IRE, iron regulatory protein binding controls EPAS1 mRNA translation in response to cellular iron availability. Our results uncover a regulatory

Mayka Sanchez; Bruno Galy; Martina U Muckenthaler; Matthias W Hentze

2007-01-01

432

Hepcidin expression inversely correlates with the expression of duodenal iron transporters and iron absorption in rats  

Microsoft Academic Search

Background & Aims: Hepcidin is an antimicrobial peptide thought to be involved in the regulation of intestinal iron absorption. To further investigate its role in this process, we examined hepatic and duodenal gene expression in rats after the switch from a control diet to an iron-deficient diet. Methods: Adult rats on an iron-replete diet were switched to an iron-deficient diet

David M. Frazer; Sarah J. Wilkins; Erika M. Becker; Christopher D. Vulpe; Andrew T. Mckie; Deborah Trinder; Gregory J. Anderson

2002-01-01

433

Influence of Iron Reducing Bacteria on Phosphate and Arsenate Release and Sequestration Onto Iron Oxides  

NASA Astrophysics Data System (ADS)

This study investigates the potential for iron oxides to capture phosphate and arsenate. While iron oxides clearly bind phosphate and arsenate, one should not assume that iron oxides would straightforwardly trap these contaminants. Instead, iron oxides in shallow groundwater sediments undergo chemical transformations that could lead to the release of sorbed contaminants. Most notably, scientists commonly observe that the biologically driven reduction of ferric iron (Fe[III]) to ferrous iron (Fe[II]) releases phosphate and/or arsenate under some conditions. Despite this observation, it is generally unclear whether iron reduction will lead to greater or lesser mobility of phosphate and arsenic. This is because sorbed phosphate and arsenate may dissolve into the aqueous phase under iron-reducing conditions, thereby becoming more mobile, while under the same reducing conditions, phosphate and arsenate may precipitate with ferrous iron solids, thus decreasing their mobility. Further complications arise when the system is exposed to cycles of oxic and anoxic conditions. Under oxic conditions, ferrous iron will oxidize and form new iron oxides, while existing solid ferrous oxides will transform to new ferric oxides. In shallow groundwater, flooding and drought lead to cycles of oxic and anoxic conditions that could produce cyclic patterns in iron redox states and in the mobility of arsenic and phosphate. To better predict the evolution of arsenate and phosphate in the field, this research employs a simplified laboratory model. This study tracks the fate of arsenate and phosphate sorbed onto goethite, a common sediment component, as geobacter sulfurreducens reduces iron from Fe[III] to Fe[II], and after re-oxidation of reduced iron. By studying that particular phenomenon, this research sheds light on how microbes and one soil constituent influence the mobility of arsenate and phosphate contamination. The results of this study show that freshly precipitated ferrous iron solids can sequester arsenate and phosphate as they remove these anions from the aqueous phase and incorporate them into the matrix of freshly precipitated ferrous iron solids.

MacDonald, L. H.; Durrant, L. R.; Jaffe, P. R.

2008-12-01

434

Secreted pyomelanin of Legionella pneumophila promotes bacterial iron uptake and growth under iron-limiting conditions.  

PubMed

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

Zheng, Huaixin; Chatfield, Christa H; Liles, Mark R; Cianciotto, Nicholas P

2013-11-01

435

Leishmania chagasi: uptake of iron bound to lactoferrin or transferrin requires an iron reductase  

Microsoft Academic Search

Leishmania chagasi can utilize iron bound to transferrin, lactoferrin, or other chelates. We investigated the mechanism of iron uptake. Promastigotes preferentially took up iron in a reduced rather than an oxidized form, suggesting that extracellular iron must be reduced prior to internalization. Similar to literature reports, a 70-kDa protein in promastigote membrane-containing microsomes bound to [125I]-labeled transferrin. However, [125I]lactoferrin and

Mary E. Wilson; Troy S. Lewis; Melissa A. Miller; Michael L. McCormick; Bradley E. Britigan

2002-01-01

436

Efficacy and safety of intravenous iron sucrose in treating adults with iron deficiency anemia  

PubMed Central

Background Iron deficiency is the most common disorder in the world, affecting approximately 25% of the world`s population and the most common cause of anemia. Objective To evaluate the efficacy and safety of intravenous iron sucrose (IS) in the treatment of adults with iron deficiency anemia Methods Eighty-six adult patients with iron deficiency anemia, who had intolerance or showed no effect with oral iron therapy, received a weekly dose of 200 mg of intravenous iron sucrose until the hemoglobin level was corrected or until receiving the total dose of intravenous iron calculated for each patient Results The mean hemoglobin and serum ferritin levels were 8.54 g/dL and 7.63 ng/mL (pre-treatment) and 12.1 g/dL and 99.0 ng/mL (post-treatment) (p-value < 0.0001), respectively. The average increases in hemoglobin levels were 3.29 g/dL for women and 4.58 g/dL for men; 94% of male and 84% of female patients responded (hemoglobin increased by at least 2 g/dL) to intravenous iron therapy. Correction of anemia was obtained in 47 of 69 (68.1%) female patients and in 12 of 17 male (70.6%) patients. A total of 515 intravenous infusions of iron sucrose were administered and iron sucrose was generally well tolerated with no moderate or serious adverse drug reactions recorded by the investigators. Conclusions Our data confirm that the use of intravenous iron sucrose is a safe and effective option in the treatment of adult patients with iron deficiency anemia who lack satisfactory response to oral iron therapy. Intravenous iron sucrose is well tolerated and with a clinically manageable safety profile when using appropriate dosing and monitoring. The availability of intravenous iron sucrose would potentially improve compliance and thereby reduce morbidities from iron deficiency.

Cancado, Rodolfo Delfini; de Figueiredo, Pedro Otavio Novis; Olivato, Maria Cristina Albe; Chiattone, Carlos Sergio

2011-01-01

437

Synthesis of Iron-Iron Oxide Core Shell Nanoclusters for Environmental Applications  

Microsoft Academic Search

Nanoscale iron particles have gained much attention recently for their potential application in the remediation of a wide variety of common environmental contaminants. Fe0 iron nanoparticles are difficult to synthesize by conventional methods. Here we report room-temperature synthesis of iron-iron oxide core-shell nanoclusters using a new type of source. Oxide shells act as passivation layers preventing further oxidation of the

Antony Jiji; You Qiang; Baer R; David E. McCready; Engelhard H

2004-01-01

438

Hemoglobin, Packed Cell Volume, Serum Iron and Iron Binding Capacity of Selected Athletes During Training  

Microsoft Academic Search

Hematological findings obtained by screening topathletes during training in The Neterlands reveal an occurrence of iron-deficient anemia of 2% in male and 2.5% in female athletes. In addition, 3% of the athletes have mild anemia without signs of iron depletion. Moreover, iron depletion without anemia as well as latent iron deficiency without anemia was present in 3, respectively 5% of

J. F. de Wijn; J. L. de Jongste; W. Mosterd; D. Willebrand

1971-01-01

439

Iron requirement and siderophore production in Rhizobium ciceri during growth on an iron-deficient medium  

Microsoft Academic Search

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

E. L. Berraho; D. Lesueur; H. G. Diem; A. Sasson

1997-01-01

440

Synthesis of iron fertilization experiments: From the Iron Age in the Age of Enlightenment  

NASA Astrophysics Data System (ADS)

Comparison of eight iron experiments shows that maximum Chl a, the maximum DIC removal, and the overall DIC/Fe efficiency all scale inversely with depth of the wind mixed layer (WML) defining the light environment. Moreover, lateral patch dilution, sea surface irradiance, temperature, and grazing play additional roles. The Southern Ocean experiments were most influenced by very deep WMLs. In contrast, light conditions were most favorable during SEEDS and SERIES as well as during IronEx-2. The two extreme experiments, EisenEx and SEEDS, can be linked via EisenEx bottle incubations with shallower simulated WML depth. Large diatoms always benefit the most from Fe addition, where a remarkably small group of thriving diatom species is dominated by universal response of Pseudo-nitzschia spp. Significant response of these moderate (10-30 ?m), medium (30-60 ?m), and large (>60 ?m) diatoms is consistent with growth physiology determined for single species in natural seawater. The minimum level of "dissolved" Fe (filtrate < 0.2 ?m) maintained during an experiment determines the dominant diatom size class. However, this is further complicated by continuous transfer of original truly dissolved reduced Fe(II) into the colloidal pool, which may constitute some 75% of the "dissolved" pool. Depth integration of carbon inventory changes partly compensates the adverse effects of a deep WML due to its greater integration depths, decreasing the differences in responses between the eight experiments. About half of depth-integrated overall primary productivity is reflected in a decrease of DIC. The overall C/Fe efficiency of DIC uptake is DIC/Fe ˜ 5600 for all eight experiments. The increase of particulate organic carbon is about a quarter of the primary production, suggesting food web losses for the other three quarters. Replenishment of DIC by air/sea exchange tends to be a minor few percent of primary CO2 fixation but will continue well after observations have stopped. Export of carbon into deeper waters is difficult to assess and is until now firmly proven and quite modest in only two experiments.

de Baar, Hein J. W.; Boyd, Philip W.; Coale, Kenneth H.; Landry, Michael R.; Tsuda, Atsushi; Assmy, Philipp; Bakker, Dorothee C. E.; Bozec, Yann; Barber, Richard T.; Brzezinski, Mark A.; Buesseler, Ken O.; Boyé, Marie; Croot, Peter L.; Gervais, Frank; Gorbunov, Maxim Y.; Harrison, Paul J.; Hiscock, William T.; Laan, Patrick; Lancelot, Christiane; Law, Cliff S.; Levasseur, Maurice; Marchetti, Adrian; Millero, Frank J.; Nishioka, Jun; Nojiri, Yukihiro; van Oijen, Tim; Riebesell, Ulf; Rijkenberg, Micha J. A.; Saito, Hiroaki; Takeda, Shigenobu; Timmermans, Klaas R.; Veldhuis, Marcel J. W.; Waite, Anya M.; Wong, Chi-Shing

2005-09-01

441

Functional Integration  

NASA Astrophysics Data System (ADS)

Acknowledgements; List symbols, conventions, and formulary; Part I. The Physical and Mathematical Environment: 1. The physical and mathematical environment; Part II. Quantum Mechanics: 2. First lesson: gaussian integrals; 3. Selected examples; 4. Semiclassical expansion: WKB; 5. Semiclassical expansion: beyond WKB; 6. Quantum dynamics: path integrals and operator formalism; Part III. Methods from Differential Geometry: 7. Symmetries; 8. Homotopy; 9. Grassmann analysis: basics; 10. Grassmann analysis: applications; 11. Volume elements, divergences, gradients; Part IV. Non-Gaussian Applications: 12. Poisson processes in physics; 13. A mathematical theory of Poisson processes; 14. First exit time: energy problems; Part V. Problems in Quantum Field Theory: 15. Renormalization 1: an introduction; 16. Renormalization 2: scaling; 17. Renormalization 3: combinatorics; 18. Volume elements in quantum field theory Bryce DeWitt; Part VI. Projects: 19. Projects; Appendix A. Forward and backward integrals: spaces of pointed paths; Appendix B. Product integrals; Appendix C. A compendium of gaussian integrals; Appendix D. Wick calculus Alexander Wurm; Appendix E. The Jacobi operator; Appendix F. Change of variables of integration; Appendix G. Analytic properties of covariances; Appendix H. Feynman's checkerboard; Bibliography; Index.

Cartier, Pierre; DeWitt-Morette, Cecile

2010-06-01

442

Functional Integration  

NASA Astrophysics Data System (ADS)

Acknowledgements; List symbols, conventions, and formulary; Part I. The Physical and Mathematical Environment: 1. The physical and mathematical environment; Part II. Quantum Mechanics: 2. First lesson: gaussian integrals; 3. Selected examples; 4. Semiclassical expansion: WKB; 5. Semiclassical expansion: beyond WKB; 6. Quantum dynamics: path integrals and operator formalism; Part III. Methods from Differential Geometry: 7. Symmetries; 8. Homotopy; 9. Grassmann analysis: basics; 10. Grassmann analysis: applications; 11. Volume elements, divergences, gradients; Part IV. Non-Gaussian Applications: 12. Poisson processes in physics; 13. A mathematical theory of Poisson processes; 14. First exit time: energy problems; Part V. Problems in Quantum Field Theory: 15. Renormalization 1: an introduction; 16. Renormalization 2: scaling; 17. Renormalization 3: combinatorics; 18. Volume elements in quantum field theory Bryce DeWitt; Part VI. Projects: 19. Projects; Appendix A. Forward and backward integrals: spaces of pointed paths; Appendix B. Product integrals; Appendix C. A compendium of gaussian integrals; Appendix D. Wick calculus Alexander Wurm; Appendix E. The Jacobi operator; Appendix F. Change of variables of integration; Appendix G. Analytic properties of covariances; Appendix H. Feynman's checkerboard; Bibliography; Index.

Cartier, Pierre; DeWitt-Morette, Cecile

2006-11-01

443

Thermal stabilization of iron piston rings  

SciTech Connect

This article presents the results of an investigation of the influence of the chemical composition and structure of the material on the elastic properties and heat resistance of piston rings. It is recommended that thermal stabilization of iron piston rings be done in the 600-620/sup 0/C range, which provides a polygonization structure and the maximum strength and elasticity. Alloying of irons with cerium makes it possible to broaden the thermal stabilization temperature range, to provide stabilization of the polygonized structure, and to strengthen the resistance to recrystallization. Irons with spheroidal and vermicular graphite posses higher elasticity and heat resistance than special gray irons.

Pogrebnysk, G.D.; Kuzina, M.G.

1987-11-01

444

Thermomagnetic evidence of native iron in sediments  

NASA Astrophysics Data System (ADS)

The paper summarizes the results of thermomagnetic analysis concerning the distribution of metallic iron in the sediments ranging in age from Miocene to Early Cretaceous sampled from the following sections: Gams (Austria); Verkhorech'e and Sel'bukhra (the Crimea); Kvirinaki and Tetritskaro (Georgia); Aimaki, Dzhengutai, Madzhalis, and Gergebil (Ciscaucasia, Russia); Klyuchi and Teplovka (Volga region, Russia); Koshak (Kazakhstan); and Khalats and Kara-Kala (Turkmenia). Small amounts of native iron (from 10-5% to 0.05%) are identified in 521 samples of 921 studied; i.e., iron particles are almost pervasive. This fact traces the origin of these particles to cosmic dust. Some established features point to the heterogeneous character of the cosmic dust: (a) the samples clearly fall into two groups. One group comprises the rocks that contain iron particles; the rocks of the other group are iron-free. In the first group, four intervals are distinguished where the sediments are globally enriched with iron with constant nickel content (5-6%); (b) in terms of composition, the iron particles are divided into three groups. The first group contains pure iron; the particles pertaining to the second group contain iron with a minor amount of nickel typical for kamacite; and the third group comprises the particles of Fe-Ni alloy with more than 20% nickel. The first and the second groups are ubiquitous; the particles of the third group are spread locally. They bear no relation to cosmic dust and are probably associated with the meteoritic impacts.

Pechersky, D. M.; Sharonova, Z. V.

2012-04-01

445

Iron medication-induced gastric mucosal injury.  

PubMed

Severe gastrointestinal erosion, ulcer, necrosis and strictures after an acute iron overdose are well described. However, gastric mucosal injury in patients receiving therapeutic iron has received only scant recognition despite its wide use. We report a case of iron medication-induced gastric mucosal injury in a 76-year-old male who presented with iron deficiency anemia and had been taking ferrous sulfate tablet for 4 years. Esophagogastroduodenoscopy (EGD) revealed a pale, villous appearing flat lesion along the lesser curvature of gastric body. Histopathologic examination of EGD biopsies of the flat lesion showed brown crystalline materials deposited in the lamina propria of gastric mucosa, which was accompanied with fibrosis, chronic inflammation, and foreign body reaction. The crystalline materials were covered and admixed with gastric epithelium. Prussian blue iron stain confirmed that the brown crystalline materials were iron. The iron and hemosiderin accumulation was also seen in cytoplasm of epithelial cells and lumen of fundic gastric glands. The recognition and reporting by pathologists of iron-induced changes in EGD biopsies will alert clinicians to this underrecognized but easily correctable complication by alternative forms of iron therapy, such as liquid preparation. PMID:19232839

Zhang, Xuchen; Ouyang, Jie; Wieczorek, Rosemary; DeSoto, Fidelina

2009-01-01

446

Iron oxyhydroxide mineralization on microbial extracellular polysaccharides  

NASA Astrophysics Data System (ADS)

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 (?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.