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1

Plate Rolling Modeling at Mill 5000 of OJSC ``Magnitogorsk Iron and Steel'' for Analysis and Optimization of Temperature Rates  

Microsoft Academic Search

Modeling of strip deflected mode and thermal state in rolling is an integral part of the technology and perspective rolling-mill machinery such as plate mill 5000 of the OJSC ``Magnitogorsk Iron and Steel''. To comprehend metal behavior in the deformation zone in the rough passes during plate rolling it is essential to assess the impact of various temperature factors on

V. Salganik; A. Shmakov; A. Pesin; D. Pustovoytov

2010-01-01

2

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

SciTech Connect

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

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

1981-01-01

3

Plate Rolling Modeling at Mill 5000 of OJSC ``Magnitogorsk Iron and Steel'' for Analysis and Optimization of Temperature Rates  

NASA Astrophysics Data System (ADS)

Modeling of strip deflected mode and thermal state in rolling is an integral part of the technology and perspective rolling-mill machinery such as plate mill 5000 of the OJSC ``Magnitogorsk Iron and Steel''. To comprehend metal behavior in the deformation zone in the rough passes during plate rolling it is essential to assess the impact of various temperature factors on variations in field of stress and strain intensities as well as temperature fields in deformation. To do such researches in consideration of various software products and adequate results one of the most effective methods nowadays is regarded as the method of finite elements. The research shows modeling of roughing rolling of a pipe steel sheet with strength category X80 according to standard API-5L. In the research of the metal deflected mode software product DEFORM 2D has been used for the isothermal and nonisothermic process. The mathematical modeling allows revealing the impact of temperature field on the metal deflected mode in the rough passes in plate rolling. Supposedly, it is deformation heating that can have more impact on the ingot temperature profile in the finishing passes in controlled rolling of the pipe steel grades. It is defined by high percent reduction, rolling speeds; more area of heat exchange surface; less thickness and lower temperature of rolling. The results can be used to develop efficient modes of plate rolling of the pipe steels.

Salganik, V.; Shmakov, A.; Pesin, A.; Pustovoytov, D.

2010-06-01

4

The lost centre: Magnitogorsk revisited  

Microsoft Academic Search

The following article sketches the history of Magnitogorsk, once the most exciting new industrial city in the Soviet Union under Stalin, and recently experiencing the problems of a city in transition. It is argued that even under a rigid planned economy city development is shaped by continuously changing paradigms. It is interesting to find the political and economic history of

Uwe Altrock

1998-01-01

5

Investigation of the formation of hydrogen cyanide in the coking of kuzbass coal. [Magnitogorsk Integrated Iron and Steel Works-USSR  

SciTech Connect

The experiments were performed using equipment which practically excluded deep pyrolysis of the vapor gas products. The hydrogen cyanide was recovered with 0.1 N caustic soda solution in the temperature range of 500 to 1000/sup 0/C. The HCN concentration was measured photometrically by the acid derivative formed as a result of the reaction of the cyanide radical with the barbituric acid amines. The dynamics of the HCN yield were investigated as a function of the heating rate, the degree of comminuition of the coal types and the charge. 2/3 of the HCN is formed as a result of pyrolysis of the vapor-gas products and 1/3 is attributed to the thermochemical conversion of organic matter.

Grigorev, N.P.; Zhilyaev, Yu.A.; Akulov, P.V.

1981-01-01

6

Slag treatment at Kardemir integrated iron and steel works  

Microsoft Academic Search

Integrated iron- and steelmaking plants generate large amounts of solid wastes, which are mainly blast furnace and steel furnace slags, dusts, sludges, etc. The main problem faced at Kardemir integrated iron and steel works is with the steelmaking slags, i.e. open-hearth furnace slag and more recently basic oxygen furnaces (BOF) slag. Over the last 50 years of operation, more than

Y. Topkaya; N. Sevinç; A. Günayd?n

2004-01-01

7

A novel streptococcal integrative conjugative element involved in iron acquisition.  

PubMed

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 (55)Fe 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. PMID:18990191

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

2008-12-01

8

Integrated modeling and heat treatment simulation of austempered ductile iron  

NASA Astrophysics Data System (ADS)

The integrated modeling and simulation of the casting and heat treatment processes for producing austempered ductile iron (ADI) castings is presented. The focus is on describing different models to simulate the austenitization, quenching and austempering steps during ADI heat treatment. The starting point for the heat treatment simulation is the simulated microstructure after solidification and cooling. The austenitization model considers the transformation of the initial ferrite-pearlite matrix into austenite as well as the dissolution of graphite in austenite to attain a uniform carbon distribution. The quenching model is based on measured CCT diagrams. Measurements have been carried out to obtain these diagrams for different alloys with varying Cu, Ni and Mo contents. The austempering model includes nucleation and growth kinetics of the ADI matrix. The model of ADI nucleation is based on experimental measurements made for varied Cu, Ni, Mo contents and austempering temperatures. The ADI kinetic model uses a diffusion controlled approach to model the growth. The models have been integrated in a tool for casting process simulation. Results are shown for the optimization of the heat treatment process of a planetary carrier casting.

Hepp, E.; Hurevich, V.; Schäfer, W.

2012-07-01

9

Integrated analysis for evaluation of an iron mine by geophysical and geostatistical approach  

NASA Astrophysics Data System (ADS)

Multiple geophysical data (DC resistivity, IP and magnetic survey), borehole and geological information and sample ore analyses were geostatistically integrated to evaluate an iron mine in three-dimensional way. Downscaling of geophysical data was used to overcome the problem of different frequency of each result. Relation between different physical properties, used for integration of different kinds of information, was classified from the sample ores. The finally integrated model explains the delineation of the economically profitable area of iron mine, and may provide information on the quality of the mine.

Suh, B.; Oh, S.; Noh, M.; Ahn, T.

2011-12-01

10

IRON  

Technology Transfer Automated Retrieval System (TEKTRAN)

Iron is an essential mineral. Although abundant in nature, it is mostly insoluble and biological absorbable forms are limited to most organisms. Iron is of fundamental importance to a variety of iron-containing proteins, especially the oxygen-carrying molecules hemoglobin and myoglobin. Iron may als...

11

Integrated Iron and Nitrogen Control for Lake Restoration.  

National Technical Information Service (NTIS)

The project is unique in that nitrogen is the focus of the lake management program; whereas phosphorus is the focus in all the other Clean Lake Programs. In addition, this program is unique in that it deals with the impact of the micro-nutrient iron in th...

J. B. Carr

1979-01-01

12

Iron  

MedlinePLUS

... high in calories but low in vitamins and minerals. Sugar sweetened sodas and most desserts are examples ... higher doses of iron supplementation [ 86 ]. Iron and mineral interactions Some researchers have raised concerns about interactions ...

13

IRON  

EPA Science Inventory

The document surveys the effects of organic and inorganic iron that are relevant to humans and their environment. The biology and chemistry of iron are complex and only partially understood. Iron participates in oxidation reduction processes that not only affect its geochemical m...

14

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...

15

Effects of fluctuating iron dosage on nitrification in integrated fixed film and conventional activated sludge processes.  

PubMed

An integrated fixed-film activated sludge (IFFAS) process with four media cells is operating in parallel with a conventional activated sludge (CAS) train at Lakeview Wastewater Treatment Plant (Ontario, Canada). During winter 2007, an intensive sampling campaign was conducted to monitor the temporal and spatial variations of the nitrification capacity within the two plug-flow reactors. At the beginning of the six-week study, the CAS train was partially nitrifying, whereas the IFFAS train was nitrifying completely using the first two IFFAS cells only. Within one week, the CAS train lost nitrification because of a drop in solids retention time and pH caused by the onset of iron overdosing. When the IFFAS train received an iron spike, the carriers at the injection point (first cell) became iron-coated and lost 80% of their nitrification capacity. However, this train maintained its total nitrification capacity using the reserve capacity in the three remaining cells. PMID:19860147

Stricker, Anne-Emmanuelle; Lishman, Lori; Barrie, Ashley

16

MMS19 assembles iron-sulfur proteins required for DNA metabolism and genomic integrity  

PubMed Central

Instability of the nuclear genome is a hallmark of cancer and aging. MMS19 protein has been linked to maintenance of genomic integrity but the molecular basis of this connection is unknown. Here, we identify MMS19 as a member of the cytosolic iron-sulfur protein assembly (CIA) machinery. MMS19 functions as part of the CIA targeting complex that specifically interacts with and facilitates iron-sulfur cluster insertion into apoproteins involved in methionine biosynthesis, DNA replication, DNA repair and telomere maintenance. MMS19 thus serves as an adapter between early-acting CIA components and a subset of cellular iron-sulfur proteins. The function of MMS19 in maturation of crucial components of DNA metabolism may explain the sensitivity of MMS19 mutants to DNA damage and the presence of extended telomeres.

Stehling, Oliver; Vashisht, Ajay A.; Mascarenhas, Judita; Jonsson, Zophonias O.; Sharma, Tanu; Netz, Daili J.A.; Pierik, Antonio J.; Wohlschlegel, James A.; Lill, Roland

2012-01-01

17

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

18

FISICA Integral Field Spectroscopy of the Shocked Iron Gas in the Supernova Remnant G11.2--0.3  

NASA Astrophysics Data System (ADS)

We have recently discovered strong iron line ([Fe II] (lambda)1.644 (mu)m) emission in the young supernova remnant G11.2-0.3. The iron line emission occurs at the south-eastern shell edge of G11.2-0.3, and positionally overlaps with the very strong X-ray and radio emission of the supernova remnant. The iron line emission is most likely caused by the shock acceleration of G11.2-0.3 interacting with the ambient medium. We propose to carry out JH-band integral-field spectroscopy of the two iron line clumps in G11.2-0.3 with FISICA, an image-slicing integral-field unit for FLAMINGOS, which will give us a uniquely comprehensive view of the strong shock acceleration of a SNR.

Moon, Dae-Sik; Eikenberry, Stephen S.; Koo, Bon-Chul; Raines, S. Nicholas; Gruel, Nicolas

2006-02-01

19

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

Microsoft Academic Search

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

Jamie A O'Rourke; Rex T Nelson; David Grant; Jeremy Schmutz; Jane Grimwood; Steven Cannon; Carroll P Vance; Michelle A Graham; Randy C Shoemaker

2009-01-01

20

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

2013-02-08

21

Integrated magnetooptic Bragg cell modulator in yttrium iron garnet-gadolinium gallium garnet taper waveguide and applications  

Microsoft Academic Search

An integrated magnetooptic (MO) device which consists of an ion-milled collimation-focusing lens pair and a guided-wave MO Bragg cell modulator in a yttrium iron garnet-gadolinium gallium garnet (YIG-GGG) taper waveguide substrate with dimensions of 6.0×16.0 mm 2 has been realized for the first time. Performance characteristics of the waveguide lenses including the focal spot size, sidelobe level and throughput, and

C. L. Wang; Chen S. Tsai

1997-01-01

22

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

23

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

24

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

NASA Astrophysics Data System (ADS)

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

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

2011-01-01

25

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

SciTech Connect

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

Meena, A.; El Mansori, M.; Ghidossi, P. [Arts et Metiers ParisTech, LMPF-EA 4106, Rue Saint Dominique, BP 508, 51006, Chalons-en-Champagne, Cedex (France)

2011-01-17

26

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

PubMed Central

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 in iron metabolism. To get further insight into the function and mechanism of action of Nramp proteins, we have generated isoform specific anti-Nramp1 and anti-Nramp2 antisera. Immunoblotting experiments indicate that Nramp2 is present in a number of cell types, including hemopoietic precursors, and is coexpressed with Nramp1 in primary macrophages and macrophage cell lines. Nramp2 is expressed as a 90–100-kD integral membrane protein extensively modified by glycosylation (>40% of molecular mass). Subcellular localization studies by immunofluorescence and confocal microscopy indicate distinct and nonoverlapping localization for Nramp1 and Nramp2. Nramp1 is expressed in the lysosomal compartment, whereas Nramp2 is not detectable in the lysosomes but is expressed primarily in recycling endosomes and also, to a lower extent, at the plasma membrane, colocalizing with transferrin. These findings suggest that Nramp2 plays a key role in the metabolism of transferrin-bound iron by transporting free Fe2+ across the endosomal membrane and into the cytoplasm.

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

1999-01-01

27

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

Microsoft Academic Search

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

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

2009-01-01

28

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

Microsoft Academic Search

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

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

2008-01-01

29

Thick yttrium-iron-garnet (YIG) films produced by pulsed laser deposition (PLD) for integration applications  

Microsoft Academic Search

High magnetic and dielectric quality, thick (50-100 ?m), epitaxial, yttrium-iron-garnet (YIG) films were deposited at high rate by PLD. A two-step (low temperature deposition followed by rapid thermal anneal) low thermal budget PLD process was demonstrated suitable to deposit thick polycrystalline YIG films on metallized Si and GaAs. A modified PLD apparatus is used to deposit uniform, 80-100 ?m, thick

H. Buhay; J. D. Adam; M. R. Daniel; N. J. Doyle; M. C. Driver; G. W. Eldridge; M. H. Hanes; R. L. Messham; M. M. Sopira

1995-01-01

30

Iron-dependent degradation of IRP2 requires its C-terminal region and IRP structural integrity  

Microsoft Academic Search

BACKGROUND: Iron regulatory protein 2 (IRP2), a post-transcriptional regulator of cellular iron metabolism, undergoes iron-dependent degradation via the ubiquitin-proteasome pathway. A stretch of 73 amino acids within the N-terminal domain 1 of the protein was reported to function as an iron sensor. However, mutants lacking this fragment remain sensitive to degradation in iron-replete cells. RESULTS: To identify elements within IRP2

Jian Wang; Guohua Chen; Julie Lee; Kostas Pantopoulos

2008-01-01

31

Integrating naive Bayes models and external knowledge to examine copper and iron homeostasis in S. cerevisiae.  

PubMed

A novel suite of analytical techniques and visualization tools are applied to 78 published transcription profiling experiments monitoring 5,687 Saccharomyces cerevisiae genes in studies examining cell cycle, responses to stress, and diauxic shift. A naive Bayes model discovered and characterized 45 classes of gene profile vectors. An enrichment measure quantified the association between these classes and specific external knowledge defined by four sets of categories to which genes can be assigned: 106 protein functions, 5 stages of the cell cycle, 265 transcription factors, and 16 chromosomal locations. Many of the 38 genes in class 42 are known to play roles in copper and iron homeostasis. The 17 uncharacterized open reading frames in this class may be involved in similar homeostatic processes; human homologs of two of them could be associated with as yet undefined disease states arising from aberrant metal ion regulation. The Met4, Met31, and Met32 transcription factors may play a role in coregulating genes involved in copper and iron metabolism. Extensions of the simple graphical model used for clustering to learning more complex models of genetic networks are discussed. PMID:11120873

Moler, E J; Radisky, D C; Mian, I S

2000-12-18

32

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); Jiang, H. [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)

1999-03-01

33

Integrating iron and oxygen\\/antioxidant signals via a combinatorial array of DNA – (antioxidant response elements) and mRNA (iron responsive elements) sequences  

Microsoft Academic Search

Fe (cellular iron), O (dioxygen, antioxidant inducers, hydrogen peroxide), and P (protein phosphorylation) signals combine to regulate DNA activity (transcription\\/mRNA synthesis) for antioxidant\\/Phase II response proteins (e.g., ferritin H, ferritin L, thioredoxin reductase I, NAD(P)H quinone oxido-reductase, heme oxygenase1 and ?-globin) and mRNA activity for proteins of iron transport, storage or oxygen metabolism (e.g., ferritin H, ferritin L, transferrin receptor1,

Elizabeth C. Theil

2006-01-01

34

Integration of Genome-Scale Metabolic Nodels of Iron-Reducing Bacteria With Subsurface Flow and Geochemical Reactive Transport Models  

NASA Astrophysics Data System (ADS)

Several field and laboratory experiments have demonstrated that the growth and activity of iron-reducing bacteria can be stimulated in many subsurface environments by amendment of groundwater with a soluble electron donor. Under strong iron-reducing conditions, these organisms mediate reactions that can impact a wide range of subsurface contaminants including chlorinated hydrocarbons, metals, and radionuclides. Therefore there is strong interest in in-situ bioremediation as a potential technology for cleanup of contaminated aquifers. To evaluate and design bioremediation systems, as well as to evaluate the viability of monitored natural attenuation as an alternative, quantitative models of biogeochemically reactive transport are needed. To date, most such models represent microbial activity in terms of kinetic rate (e.g., Monod- type) formulations. Such models do not account for fundamental changes in microbial functionality (such as utilization of alternative respiratory pathways) that occur as the result of spatial and temporal variations in the geochemical environment experienced by microorganisms. Constraint-based genome-scale in silico models of microbial metabolism present an alternative to simplified rate formulations that provide flexibility to account for changes in microbial function in response to local geochemical conditions. We have developed and applied a methodology for coupling a constraint-based in silico model of Geobacter sulfurreducens with a conventional model of groundwater flow, transport, and geochemical reaction. Two uses of the in silico model are tested: 1) incorporation of modified microbial growth yield coefficients based on the in silico model, and 2) variation of reaction rates in a reactive transport model based on in silico modeling of a range of local geochemical conditions. Preliminary results from this integrated model will be presented.

Scheibe, T. D.; Mahadevan, R.; Fang, Y.; Garg, S.; Long, P. E.; Lovley, D. M.

2008-12-01

35

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

PubMed

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

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

2010-09-10

36

Degradation of a biorecalcitrant dye precursor present in industrial wastewaters by a new integrated iron(III) photoassisted–biological treatment  

Microsoft Academic Search

This study focuses on the mineralization of 5-amino-6-methyl-2-benzimidazolone (AMBI), an important precursor in the industrial production of dyes, through an integrated Fe(III) photoassisted–biological system without addition of other electron acceptor than O2. The iron photoassisted process produces a biocompatible solution, removing 100% of the initial biorecalcitrant compound and 40% of the Dissolved Organic Carbon (DOC), and then the complete mineralization

V Sarria; M Deront; P Péringer; C Pulgarin

2003-01-01

37

Iron and Iron Deficiency  

MedlinePLUS

... them to get enough iron from their normal diet. Women who are pregnant have higher iron needs. To ... iron sources in the diet (e.g., vegetarian diets) Low absorption Taking antacids beyond ... Young children and pregnant women are at higher risk of iron deficiency because ...

38

Curie temperature, exchange integrals, and magneto-optical properties in off-stoichiometric bismuth iron garnet epitaxial films  

Microsoft Academic Search

We have studied the influence of the stoichiometry on the structural, magnetic, and magneto-optical properties of bismuth iron garnet (Bi3Fe5O12) thin films grown by pulsed laser deposition. Films with different stoichiometries have been obtained by varying the Bi\\/Fe ratio of the target and the oxygen pressure during deposition. Stoichiometry variations influence the Curie temperature TC by tuning the (Fe)-O-[Fe] geometry:

B. Vertruyen; R. Cloots; J. S. Abell; T. J. Jackson; R. C. da Silva; E. Popova; N. Keller

2008-01-01

39

The DUF59 Family Gene AE7 Acts in the Cytosolic Iron-Sulfur Cluster Assembly Pathway to Maintain Nuclear Genome Integrity in Arabidopsis[C][W][OA  

PubMed Central

Eukaryotic organisms have evolved a set of strategies to safeguard genome integrity, but the underlying mechanisms remain poorly understood. Here, we report that ASYMMETRIC LEAVES1/2 ENHANCER7 (AE7), an Arabidopsis thaliana gene encoding a protein in the evolutionarily conserved Domain of Unknown Function 59 family, participates in the cytosolic iron-sulfur (Fe-S) cluster assembly (CIA) pathway to maintain genome integrity. The severe ae7-2 allele is embryo lethal, whereas plants with the weak ae7 (ae7-1) allele are viable but exhibit highly accumulated DNA damage that activates the DNA damage response to arrest the cell cycle. AE7 is part of a protein complex with CIA1, NAR1, and MET18, which are highly conserved in eukaryotes and are involved in the biogenesis of cytosolic and nuclear Fe-S proteins. ae7-1 plants have lower activities of the cytosolic [4Fe-4S] enzyme aconitase and the nuclear [4Fe-4S] enzyme DNA glycosylase ROS1. Additionally, mutations in the gene encoding the mitochondrial ATP binding cassette transporter ATM3/ABCB25, which is required for the activity of cytosolic Fe-S enzymes in Arabidopsis, also result in defective genome integrity similar to that of ae7-1. These results indicate that AE7 is a central member of the CIA pathway, linking plant mitochondria to nuclear genome integrity through assembly of Fe-S proteins.

Luo, Dexian; Bernard, Delphine G.; Balk, Janneke; Hai, Huang; Cui, Xiaofeng

2012-01-01

40

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

PubMed Central

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.

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

2011-01-01

41

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

2011-08-30

42

Regulation of cellular iron metabolism  

PubMed Central

Iron is an essential but potentially hazardous biometal. Mammalian cells require sufficient amounts of iron to satisfy metabolic needs or to accomplish specialized functions. Iron is delivered to tissues by circulating transferrin, a transporter that captures iron released into the plasma mainly from intestinal enterocytes or reticuloendothelial macrophages. The binding of iron-laden transferrin to the cell-surface transferrin receptor 1 results in endocytosis and uptake of the metal cargo. Internalized iron is transported to mitochondria for the synthesis of haem or iron–sulfur clusters, which are integral parts of several metalloproteins, and excess iron is stored and detoxified in cytosolic ferritin. Iron metabolism is controlled at different levels and by diverse mechanisms. The present review summarizes basic concepts of iron transport, use and storage and focuses on the IRE (iron-responsive element)/IRP (iron-regulatory protein) system, a well known post-transcriptional regulatory circuit that not only maintains iron homoeostasis in various cell types, but also contributes to systemic iron balance.

Wang, Jian; Pantopoulos, Kostas

2011-01-01

43

Accelerated dynamic leaching of iron from soil with on-line derivatization and integrated concentration-detection.  

PubMed

A module for continuous high pressure-temperature leaching is proposed. The overall approach involves the coupling of an extractor with a continuous-flow manifold where the analyte forms a complex with SCN(-), which is driven to a flow-cell packed with a suitable material for retention and continuous monitoring of this process which in turn is a way for indirect monitoring of the leaching kinetics. The approach has been used for the determination of iron in soil after leaching and derivatization. The sensitivity of the method (ng level) and the short time required (only 15 min versus 24 h for leaching and 30 min for the measurement step required by the conventional method), together with its precision (RSD less than 9%) makes this method an excellent alternative to the conventional procedure. PMID:18967074

Jiménez-Carmona, M M; da Silva, M P; Luque de Castro, M D

1998-03-01

44

Atmospheric Iron Deposition: Global Distribution, Variability, and Human Perturbations  

Microsoft Academic Search

Atmospheric inputs of iron to the open ocean are hypothesized to modulate ocean biogeochemistry. This review presents an integration of available observations of atmospheric iron and iron deposition, and also covers bioavailable iron distributions. Methods for estimating temporal variability in ocean deposition over the recent past are reviewed. Desert dust iron is estimated to represent 95% of the global atmospheric

Natalie M. Mahowald; Sebastian Engelstaedter; Chao Luo; Andrea Sealy; Paulo Artaxo; Claudia Benitez-Nelson; Sophie Bonnet; Ying Chen; Patrick Y. Chuang; David D. Cohen; Francois Dulac; Barak Herut; Anne M. Johansen; Nilgun Kubilay; Remi Losno; Willy Maenhaut; Adina Paytan; Joseph M. Prospero; Lindsey M. Shank; Ronald L. Siefert

2009-01-01

45

Atmospheric iron deposition: global distribution, variability, and human perturbations.  

PubMed

Atmospheric inputs of iron to the open ocean are hypothesized to modulate ocean biogeochemistry. This review presents an integration of available observations of atmospheric iron and iron deposition, and also covers bioavailable iron distributions. Methods for estimating temporal variability in ocean deposition over the recent past are reviewed. Desert dust iron is estimated to represent 95% of the global atmospheric iron cycle, and combustion sources of iron are responsible for the remaining 5%. Humans may be significantly perturbing desert dust (up to 50%). The sources of bioavailable iron are less well understood than those of iron, partly because we do not know what speciation of the iron is bioavailable. Bioavailable iron can derive from atmospheric processing of relatively insoluble desert dust iron or from direct emissions of soluble iron from combustion sources. These results imply that humans could be substantially impacting iron and bioavailable iron deposition to ocean regions, but there are large uncertainties in our understanding. PMID:21141037

Mahowald, Natalie M; Engelstaedter, Sebastian; Luo, Chao; Sealy, Andrea; Artaxo, Paulo; Benitez-Nelson, Claudia; Bonnet, Sophie; Chen, Ying; Chuang, Patrick Y; Cohen, David D; Dulac, Francois; Herut, Barak; Johansen, Anne M; Kubilay, Nilgun; Losno, Remi; Maenhaut, Willy; Paytan, Adina; Prospero, Joseph M; Shank, Lindsey M; Siefert, Ronald L

2009-01-01

46

The Integrated Role of Desferrioxamine and Phenserine Targeted to an Iron-Responsive Element in the APP-mRNA 5'-Untranslated Region  

Microsoft Academic Search

The Alzheimer's amyloid precursor protein (APP) is the metallo- protein that is cleaved to generate the pathogenic Apeptide. We showed that iron closely regulated the expression of APP by 5'-untranslated region (5'- UTR) sequences in APP mRNA. Iron modulated APP holoprotein expression by a pathway similar to iron control of the translation of the ferritin-L and -H mRNAs by iron-responsive

AMANDA VENTI; TONY GIORDANO; PAUL EDER; ASHLEY I. BUSH; DEBOMOY K. LAHIRI; NIGEL H. GREIG; JACK T. ROGERSa

2004-01-01

47

Drug-loaded and superparamagnetic iron oxide nanoparticle surface-embedded amphiphilic block copolymer micelles for integrated chemotherapeutic drug delivery and MR imaging.  

PubMed

We report on the fabrication of organic/inorganic hybrid micelles of amphiphilic block copolymers physically encapsulated with hydrophobic drugs within micellar cores and stably embedded with superparamagnetic iron oxide (SPIO) nanoparticles within hydrophilic coronas, which possess integrated functions of chemotherapeutic drug delivery and magnetic resonance (MR) imaging contrast enhancement. Poly(?-caprolactone)-b-poly(glycerol monomethacrylate), PCL-b-PGMA, and PCL-b-P(OEGMA-co-FA) amphiphilic block copolymers were synthesized at first by combining ring-opening polymerization (ROP), atom transfer radical polymerization (ATRP), and post- modification techniques, where OEGMA and FA are oligo(ethylene glycol) monomethyl ether methacrylate and folic acid-bearing moieties, respectively. A model hydrophobic anticancer drug, paclitaxel (PTX), and 4 nm SPIO nanoparticles were then loaded into micellar cores and hydrophilic coronas, respectively, of mixed micelles fabricated from PCL-b-PGMA and PCL-b-P(OEGMA-co-FA) diblock copolymers by taking advantage of the hydrophobicity of micellar cores and strong affinity between 1,2-diol moieties in PGMA and Fe atoms at the surface of SPIO nanoparticles. The controlled and sustained release of PTX from hybrid micelles was achieved, exhibiting a cumulative release of ~61% encapsulated drugs (loading content, 8.5 w/w%) over ~130 h. Compared to that of surfactant-stabilized single SPIO nanoparticles (r(2) = 28.3 s(-1) mM(-1) Fe), the clustering of SPIO nanoparticles within micellar coronas led to considerably enhanced T(2) relaxivity (r(2) = 121.1 s(-1) mM(-1) Fe), suggesting that hybrid micelles can serve as a T(2)-weighted MR imaging contrast enhancer with improved performance. Moreover, preliminary experiments of in vivo MR imaging were also conducted. These results indicate that amphiphilic block copolymer micelles surface embedded with SPIO nanoparticles at the hydrophilic corona can act as a new generation of nanoplatform integrating targeted drug delivery, controlled release, and disease diagnostic functions. PMID:22047551

Hu, Jinming; Qian, Yinfeng; Wang, Xiaofeng; Liu, Tao; Liu, Shiyong

2011-11-11

48

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

2009-02-06

49

Using Integrated Approaches of Modeling, In-situ Observations and Laboratory Experiments to Study Aeolian Iron Solubility and Input to the Ocean  

NASA Astrophysics Data System (ADS)

Aeolian dust input is an important source of iron (Fe) for phytoplankton growth in some oceanic regions. However, the efficiency of Fe uptake by phytoplankton may partly depend on Fe properties, in particular Fe solubility and speciation, as soluble Fe is believed to be more readily used by marine organisms. Many processes in the atmosphere, such as interactions between dust particles and pollution derived substances, may alter dust properties and then Fe bioavailability. Here we discuss our efforts of taking integrated approaches to quantify Fe solubility and its input to the ocean that include model simulations, in-situ measurements and laboratory experiments. We use the MOZART-2 atmospheric transport model to simulate the heterogeneous processes and magnitude of soluble Fe deposition to the ocean. We conduct field measurements to investigate the interactions of different aerosol species focusing on their particle size- distributions using a MOUDI impactor. We also target certain Fe-containing minerals to test Fe solubility through laboratory procedures. Preliminary results suggest that heterogeneous chemical processes play an important role on Fe solubility. More detailed discussions of the results will be given at this session.

Gao, Y.; Yang, H.; Zhao, Y.; Jusino-Atresino, R.; Xu, N.; Thuman, C.

2006-12-01

50

Iron overdose  

MedlinePLUS

Ferrous sulfate overdose; Ferrous gluconate overdose; Ferrous fumarate overdose ... Iron is an ingredient in many mineral and vitamin supplements. Iron ... (Femiron, Feostat) Note: This list may not be all-inclusive.

51

Integral neutron kerma coefficient ratios for silicon, iron, and oxygen to carbon on the energy range from 15 to 30 MeV  

NASA Astrophysics Data System (ADS)

Kerma coefficient ratios are reported for carbon to oxygen, silicon, and iron in the energy range of 15 to 30 MeV. The determination was done by measuring dose to the gas of proportional counters exposed to a well characterized neutron field. The measured dose in the proportional counter gas was then converted to dose in the proportional counter wall material applying Bragg-Gray theory. The proportional counters were made of the material of interest. The oxygen measurement was done by irradiating simultaneously zirconium and zirconium oxide proportional counters and substracting the dose to the zirconium from the zirconium oxide. Neutrons were generated with the UW Tandem Accelerator. The reaction 3H(d, n)4 He provided our neutron source which consisted of monoenergetic neutrons. Neutron spectra measurements were carried out for the 27.3 MeV neutron energy. This was necessary because of the presence of contaminating breakup neutrons at this energy. The spectra were measured with a pulse beam time-of-flight spectrometer and a NE-213 liquid scintillator. The dose conversion factor r is reported for carbon, oxygen, silicon, iron, zirconium, and zirconium oxide relative to TE-propane gas at neutron energies of 20, 23 and 27 MeV. The factor r, which relates the dose to the gas to that of the proportional counter through the Bragg-Gray theory, was calculated from angle integrated differential cross sections. This required a calculation of the initial energy spectra as well as the differential secondary charged particle energy spectra and for the first time a complete treatment of all heavy ions is considered. Furthermore, as the conditions required to apply the Bragg-Gray theory are difficult to satisfy (infinitesimal cavity), we report the calculation of the dose conversion factor r for the finite cavity case for carbon/TE-gas in order to test the validity of the application of the theory to this type of applications. We found that the two conditions of the Bragg-Gray theory are violated: the differential secondary charged particle spectrum is perturbed by the presence of the cavity and that the dose absorbed in the cavity is not enteraly deposited by the particles crossing it. However, these changes in the spectra and the dose deposition are not very sensitive to the conversion factor r because this factor only reflects the ratio of these changes. Our results are found to be in agreement, within the uncertainty associated to the determination, with previous published values when comparable data exits.

Miranda, Juan Gustavo

2001-07-01

52

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

53

Iron chelators and iron toxicity  

Microsoft Academic Search

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

Gary M. Brittenham

2003-01-01

54

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

55

Microbial iron cycling in acidic geothermal springs of yellowstone national park: integrating molecular surveys, geochemical processes, and isolation of novel fe-active microorganisms.  

PubMed

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

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

2012-03-26

56

Iron toxicity  

PubMed Central

During the past half century, excessive/misplaced iron has been observed to be a risk factor for an increasing number and diversity of disease conditions. An extensive list of conditions and of the types of iron association were published in early 2008. Within the subsequent year, four additional disorders have been recognized to be enhanced by iron: aging muscle atrophy, viral replication, rosacea and pulmonary alveolar proteinosis. This paper adds new data and emphasis on these disorders as entities associated with increased iron load and toxicity.

2009-01-01

57

Iron refractory iron deficiency anemia.  

PubMed

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. PMID:23729726

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

2013-06-01

58

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

59

Iron chelators and iron toxicity.  

PubMed

Iron chelation may offer new approaches to the treatment and prevention of alcoholic liver disease. With chronic excess, either iron or alcohol alone may individually injure the liver and other organs. In combination, each exaggerates the adverse effects of the other. In alcoholic liver disease, both iron and alcohol contribute to the production of hepatic fibrosis through their effects on damaged hepatocytes, hepatic macrophages, hepatic stellate cells, and the extracellular matrix. The pivotal role of iron in these processes suggests that chelating iron may offer a new approach to arresting or ameliorating liver injury. For the past four decades, deferoxamine B mesylate has been the only iron-chelating agent generally available for clinical use. Clinical experience with deferoxamine has demonstrated the safety and effectiveness of iron chelation for the prevention and treatment of iron overload. Determined efforts to develop alternative agents have at last resulted in the development of a variety of candidate iron chelators that are now in or near clinical trial, including (a) the hexadentate phenolic aminocarboxylate HBED [N,N'-bis(2-hydroxybenzyl)ethylenediamine-N,N'-diacetic acid], (b) the tridentate desferrithiocin derivative 4'-OH-dadmDFT [4'-hydroxy-(S)-desazadesmethyl-desferrithiocin; (S)-4,5-dihydro-2-(2,4-dihydroxyphenyl)-4-thiazolecarboxylic acid], (c) the tridentate triazole ICL670A [CGP72 670A; 4-[3,5-bis-(hydroxyphenyl)-1,2,4-triazol-1-yl]-benzoic acid], and (d) the bidentate hydroxypyridin-4-one deferiprone [L1, CP20; 1,2-dimethyl-3-hydroxypyridin-4-one]. These agents may provide new pharmacological means of averting or ameliorating liver damage in alcoholic liver disease by binding, inactivating, and eliminating the reactive forms of iron that contribute to oxidative injury of cellular components, are involved in signal transduction, or both. PMID:12957300

Brittenham, Gary M

2003-06-01

60

Calculating iron contents of lunar highland materials surrounding Tycho crater from integrated Clementine UV-visible and near-infrared data  

Microsoft Academic Search

Optical properties of lunar surface materials are modified by exposure to the space environment, including bombardment by solar wind particles and micrometeorites. One of the main problems in the interpretation of lunar spectral observations is to separate the effects of exposure (``space weathering'') and those due to the composition of the soils (mainly iron and titanium content). Here we use

Stéphane Le Mouélic; P. G. Lucey; Yves Langevin; B. Ray Hawke

2002-01-01

61

Calculating iron contents of lunar highland materials surrounding Tycho crater from integrated Clementine UV-visible and near-infrared data  

NASA Astrophysics Data System (ADS)

Optical properties of lunar surface materials are modified by exposure to the space environment, including bombardment by solar wind particles and micrometeorites. One of the main problems in the interpretation of lunar spectral observations is to separate the effects of exposure (``space weathering'') and those due to the composition of the soils (mainly iron and titanium content). Here we use Clementine near-infrared (NIR) data to investigate this problem for highland-type soils in the Tycho crater area. Our approach is based on the methods developed for an analysis of a mare region near Aristarchus Plateau [Le Mouélic et al., 2000]. We show that the systematic relationships between spectral parameters (1-?m band depth and continuum slope), which were previously observed in a mare area with varying maturity degree, are also valid for highland-type soils. This technique aimed at evaluating the iron content of the surface materials from Clementine UV-visible (UVVIS) and near-infrared data can therefore be applied globally. This approach complements the widely used method of Lucey and coworkers, which relies on the UV-visible bands only. The proposed method relies mostly on band ratios. The iron map produced from this method is therefore less dependent on topography than the iron estimates obtained with UV-visible data alone, where brightness is one of the controlling parameters. Therefore the proposed approach should be particularly useful at middle to high latitudes, where local topography generates large variations in brightness and therefore hampers the interpretation of iron maps produced from UV-visible bands only.

Le Mouélic, Stéphane; Lucey, P. G.; Langevin, Yves; Hawke, B. Ray

2002-10-01

62

Infection structure-specific reductive iron assimilation is required for cell wall integrity and full virulence of the maize pathogen Colletotrichum graminicola.  

PubMed

Ferroxidases are essential components of the high-affinity reductive iron assimilation pathway in fungi. Two ferroxidase genes, FET3-1 and FET3-2, have been identified in the genome of the maize anthracnose fungus Colletotrichum graminicola. Complementation of growth defects of the ferroxidase-deficient Saccharomyces cerevisiae strain ?fet3fet4 showed that both Fet3-1 and Fet3-2 of C. graminicola represent functional ferroxidases. Expression of enhanced green fluorescent protein fusions in yeast and C. graminicola indicated that both ferroxidase proteins localize to the plasma membrane. Transcript abundance of FET3-1 increased dramatically under iron-limiting conditions but those of FET3-2 were hardly detectable. ?fet3-1 and ?fet3-2 single as well as ?fet3-1/2 double-deletion strains were generated. Under iron-sufficient or deficient conditions, vegetative growth rates of these strains did not significantly differ from that of the wild type but ?fet3-1 and ?fet3-1/2 strains showed increased sensitivity to reactive oxygen species. Furthermore, under iron-limiting conditions, appressoria of ?fet3-1 and ?fet3-1/2 strains showed significantly reduced transcript abundance of a class V chitin synthase and exhibited severe cell wall defects. Infection assays on intact and wounded maize leaves, quantitative data of infection structure differentiation, and infection stage-specific expression of FET3-1 showed that reductive iron assimilation is required for appressorial penetration, biotrophic development, and full virulence. PMID:23639025

Albarouki, Emad; Deising, Holger B

2013-06-01

63

Formation and occurrence of biogenic iron-rich minerals  

Microsoft Academic Search

Iron cycling in the Earth's crust depends on redox reactions, which often trigger the precipitation and dissolution of Fe-rich minerals. Microbial activity is also an integral part of iron cycling, through carbon fixation, respiration and passive sorption reactions. Iron oxides formed in close association with bacteria (either as internal or external precipitates) are referred to as biogenic minerals. They form

Danielle Fortin; Sean Langley

2005-01-01

64

Bacterial iron homeostasis.  

PubMed

Iron is essential to virtually all organisms, but poses problems of toxicity and poor solubility. Bacteria have evolved various mechanisms to counter the problems imposed by their iron dependence, allowing them to achieve effective iron homeostasis under a range of iron regimes. Highly efficient iron acquisition systems are used to scavenge iron from the environment under iron-restricted conditions. In many cases, this involves the secretion and internalisation of extracellular ferric chelators called siderophores. Ferrous iron can also be directly imported by the G protein-like transporter, FeoB. For pathogens, host-iron complexes (transferrin, lactoferrin, haem, haemoglobin) are directly used as iron sources. Bacterial iron storage proteins (ferritin, bacterioferritin) provide intracellular iron reserves for use when external supplies are restricted, and iron detoxification proteins (Dps) are employed to protect the chromosome from iron-induced free radical damage. There is evidence that bacteria control their iron requirements in response to iron availability by down-regulating the expression of iron proteins during iron-restricted growth. And finally, the expression of the iron homeostatic machinery is subject to iron-dependent global control ensuring that iron acquisition, storage and consumption are geared to iron availability and that intracellular levels of free iron do not reach toxic levels. PMID:12829269

Andrews, Simon C; Robinson, Andrea K; Rodríguez-Quiñones, Francisco

2003-06-01

65

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

SciTech Connect

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

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

1997-11-01

66

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

67

Snapshot of iron response in Shewanella oneidensis by gene network reconstruction  

Microsoft Academic Search

BACKGROUND: Iron homeostasis of Shewanella oneidensis, a ?-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.

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

2009-01-01

68

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

69

Systemic iron homeostasis.  

PubMed

The iron hormone hepcidin and its receptor and cellular iron exporter ferroportin control the major fluxes of iron into blood plasma: intestinal iron absorption, the delivery of recycled iron from macrophages, and the release of stored iron from hepatocytes. Because iron losses are comparatively very small, iron absorption and its regulation by hepcidin and ferroportin determine total body iron content. Hepcidin is in turn feedback-regulated by plasma iron concentration and iron stores, and negatively regulated by the activity of erythrocyte precursors, the dominant consumers of iron. Hepcidin and ferroportin also play a role in host defense and inflammation, and hepcidin synthesis is induced by inflammatory signals including interleukin-6 and activin B. This review summarizes and discusses recent progress in molecular characterization of systemic iron homeostasis and its disorders, and identifies areas for further investigation. PMID:24137020

Ganz, Tomas

2013-10-01

70

Disorders of iron metabolism. Part II: iron deficiency and iron overload  

Microsoft Academic Search

Main disorders of iron metabolismIncreased iron requirements, limited external supply, and increased blood loss may lead to iron deficiency (ID) and iron deficiency anaemia. In chronic inflammation, the excess of hepcidin decreases iron absorption and prevents iron recycling, resulting in hypoferraemia and iron restricted erythropoiesis, despite normal iron stores (functional iron deficiency), and finally anaemia of chronic disease (ACD), which

Manuel Muñoz; José Antonio García-Erce; Ángel Francisco Remacha

2010-01-01

71

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

72

[Control of iron deficiency in developing countries].  

PubMed

Iron deficiency is the most prevalent nutritional disorder worldwide, especially in developing countries. It occurs when iron absorption cannot compensate iron requirements and losses. Requirements are especially high in pregnant women, infants, young children and adolescents who run a higher risk of being iron-deficient. In developing countries, the main cause of iron deficiency is the low iron bioavailability of the diet. The consequences of iron deficiency are many and serious, affecting not only individuals' health but also the development of societies and countries. The prevention and the control of iron deficiency and anemia in all groups of a population with different iron requirements imply to coordinate different interventions. Iron fortification of staple foods or condiments directed to the whole population is a sustainable and low cost-effective approach. However, at some periods of life, especially during pregnancy and in children from the age of 6 months, iron requirements are high. For pregnant women, the current approach favours the daily iron-folate supplementation during pregnancy but the results in terms of public health are disappointing. The preventive weekly iron-folate supplementation of women during their reproductive life, whose efficacy is recognized, offers a promising alternative; its impact in terms of public health is under current evaluation. For infants and young children, iron fortification of complementary food is effective but this food is generally imported and economically inaccessible to populations with limited resources. The production, by small private units from local products, of complementary foods of low viscosity, good nutritional quality, fortified with vitamins and minerals, and of low cost is at hand in several countries. When complementary foods are not available, the preventive iron supplementation from 6 to 18 months of age has to be advised. This approach should be strengthened by the advantages of the weekly approach. These interventions are more effective when they integrate other approaches like the improvement of the nutritional practices, infection control and the promotion of breast-feeding and when coupled with programs aiming to control other micronutrient deficiencies. The success of most interventions requires the active participation of the individuals. Information and education of the populations, especially through social mobilization campaigns, are essential because iron deficiency induces few visible symptoms, not easily recognizable by individuals. The implementation of national nutrition plans including the control of iron deficiency as one of the priorities and the participation of the public health and education sectors, food industries, the community and the media should contribute to the success of the interventions and to the control of iron deficiency. PMID:11943635

Berger, Jacques; Dillon, Jean-Claude

73

Iron metabolism in man.  

PubMed

Iron metabolism in man is a highly regulated process designed to provide iron for erythropoiesis, mitochondrial energy production, electron transport, and cell proliferation. The mechanisms of iron handling also protect cells from the deleterious effects of free iron, which can produce oxidative damage of membranes, proteins, and lipids. Over the past decade, several important molecules involved in iron homeostasis have been discovered, and their function has expanded our understanding of iron trafficking under normal and pathological conditions. Physiologic iron metabolism is strongly influenced by inflammation, which clinically leads to anemia. Although hepcidin, a small circulating peptide produced by the liver, has been found to be the key regulator of iron trafficking, molecular pathways of iron sensing that control iron metabolism and hepcidin production are still incompletely understood. With this review, we provide an overview of the current understanding of iron metabolism, the recently discovered regulators of iron trafficking, and a focus on the effects of inflammation on the process. PMID:22968710

von Drygalski, Annette; Adamson, John W

2012-09-11

74

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

75

Taking iron supplements  

MedlinePLUS

... care provider immediately. Liquid forms of iron may stain your teeth. Try mixing the iron with water ... and drinking the medicine with a straw. Iron stains can be removed by brushing your teeth with ...

76

Hemochromatosis: Iron Storage Disease  

MedlinePLUS

... en... Favorites Delicious Digg Google Bookmarks Hemochromatosis: Iron Storage Disease Excessive iron buildup in the body's tissues ... Learn more about hemochromatosis, a type of iron storage disease, and stay healthy. What Is Hemochromatosis? Hemochromatosis ...

77

Iron metabolism and toxicity  

SciTech Connect

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 in diseases of iron overload, such as hereditary hemochromatosis or transfusional siderosis, where excessive iron accumulation results in tissue damage and organ failure. Pathological iron accumulation in the liver has also been linked to the development of hepatocellular cancer. Here we provide a background on the biology and toxicity of iron and the basic concepts of iron homeostasis at the cellular and systemic level. In addition, we provide an overview of the various disorders of iron overload, which are directly linked to iron's toxicity. Finally, we discuss the potential role of iron in malignant transformation and cancer.

Papanikolaou, G. [First Department of Internal Medicine, National and Kapodistrian University of Athens, School of Medicine, Laikon General Hospital, Athens 11527 (Greece); Pantopoulos, K. [Lady Davis Institute for Medical Research, Sir Mortimer B. Davis Jewish General Hospital, Montreal, Quebec, H3T 1E2 (Canada) and Department of Medicine, McGill University (Canada)]. E-mail: kostas.pantopoulos@mcgill.ca

2005-01-15

78

Iron and Stony-iron Meteorites  

Microsoft Academic Search

Without iron and stony-iron meteorites, our chances of ever sampling the deep interior of a differentiated planetary object would be next to nil. Although we live on a planet with a very substantial core, we will never be able to sample it. Fortunately, asteroid collisions provide us with a rich sampling of the deep interiors of differentiated asteroids.Iron and stony-iron

H. Haack; T. J. McCoy

2003-01-01

79

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

80

Pathways of Iron Absorption  

Microsoft Academic Search

ABSTRACTIron is vital for all living organisms but excess iron can be lethal because it facilitates free radical formation. Thus iron absorption is carefully regulated to maintain an equilibrium between absorption and body loss of iron. In countries where meat is a significant part of the diet, most body iron is derived from dietary heme because heme binds few of

Marcel E. Conrad; Jay N. Umbreit

2002-01-01

81

Collisional Records in Iron Meteorites  

NASA Astrophysics Data System (ADS)

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

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

1995-09-01

82

Evolution of the Microbial Community Structure and Iron Reduction Rate in a Column Biostimulation Experiment During the Transition From Iron to Sulfate Reduction  

Microsoft Academic Search

During the biostimulation of iron reducers for the purpose of concurrent biological reduction of U(VI), it has been postulated that iron reduction proceeds while bioavailable iron is present, after which the system switches to sulfate reduction if sulfate is present. Field experiments from the Rifle Integrated Field Challenge (IFC) site in Colorado showing that the onset of sulfate reduction has

P. R. Jaffe; H. Elbishlawi; R. L. Hettich; L. Kerkhof; J. Komlos; R. P. Kukkadapu; M. S. Lipton; P. E. Long; L. McGuinness; H. Moon; A. D. Peacock; N. C. Verberkmoes; K. H. Williams

2007-01-01

83

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

84

Neonatal iron nutrition.  

PubMed

Preterm infants are prone to iron deficiency. Their total body iron content at birth is low and gets further depleted by clinical practices such as uncompensated phlebotomy losses and exogenous erythropoietin administration during the neonatal period. Early iron deficiency appears to adversely affect cognitive development in human infants. To maintain iron sufficiency and meet the iron demands of catch-up postnatal growth, iron supplementation is prudent in preterm infants. A dose of 2-4 mg/kg/day is recommended for preterm infants who are fed exclusively human milk. A dose of 6 mg/kg/day or more is needed with the use of exogenous erythropoietin or to correct preexisting iron deficiency. However, due to the poor antioxidant capabilities of preterm infants and the potential role of iron in several oxidant-related perinatal disorders, indiscriminate iron supplementation should be avoided. PMID:11988032

Rao, R; Georgieff, M K

2001-10-01

85

Iron Fractionation During Microbial Reduction of Iron  

NASA Astrophysics Data System (ADS)

The isotopic fractionation of iron during the biological reduction of iron by microbes has received much attention due to the possible use of iron isotopes as an indicator of biological activity in ancient and extraterrestrial environments. However the mechanisms of dissimilatory iron reduction have not been fully characterized. We are investigating the mechanisms by which Shewanella putrefaciens strain CN32 reduces ferric iron in the form of goethite, as well as, the resulting iron isotopic fractionation. In the experiments a PIPES buffered minimal media was used in an effort to eliminate or control the formation of secondary ferrous-iron solids. S. putrefaciens is thought to also produce an electron shuttle, which carries electrons from the cell to the iron solid. In one set of experiments, S. putrefaciens was cultured in minimal media containing goethite both with and without anthraquinone-2,6-disulfonate (AQDS, an artificial electron shuttle). Preliminary data indicates that the fractionation of iron in solution in the AQDS amended cultures is -1.57 per mil lighter than the starting goethite. This fractionation corresponds well with previously reported fractionations in similar systems. However, other researchers have shown that, in these systems, much of the reduced Fe(II) sorbs to the goethite. An acid extraction is often used to remove this sorbed Fe(II) and determine the total amount of reduced iron. This extraction was used to extract sorbed Fe(II) for isotopic analysis. Although the extraction itself may cause a fractionation effect, less than 1% of the total iron in the extraction can be attributed to this effect. Therefore, the observed fractionation should be primarily a function of the microbially reduced iron and not an artifact of the extraction. The isotope fractionation in the extraction, which includes both soluble and sorbed Fe(II), is -2.42 per mil relative to the starting goethite. We are currently combining parts of the cell involved in iron reduction (cell wall components) with an electron shuttle and goethite to accomplish in vitro Fe reduction. We will compare the in vitro iron isotope fractionations that occur without live cells to those with live cultures in an effort to elucidate iron reducing mechanisms and pathways.

Icopini, G. A.; Brantley, S. L.; Ruebush, S.; Tien, M.; Bullen, T. D.

2002-12-01

86

Iron Therapy for Preterm Infants  

PubMed Central

SYNOPSIS Preterm infants are at risk for both iron deficiency and iron overload. The role of iron in multiple organ functions suggests that iron supplementation is essential for the preterm infant. Conversely, the potential for iron overload and the poorly developed anti-oxidant measures in the preterm infant argues against indiscriminate iron supplementation in this population. The purpose of this article is to review the predisposing factors and consequences of iron deficiency and iron overload in the preterm infant, the current recommendation for iron supplementation and its appropriateness, and describe potential management strategies that strike a balance between iron deficiency and iron toxicity.

Rao, Raghavendra; Georgieff, Michael K.

2009-01-01

87

Iron-Deficiency Anemia  

MedlinePLUS Videos and Cool Tools

... NHLBI Entire Site NHLBI Entire Site 1 Health Topics 2 News & Resources 3 Intramural Research 4 Home » Health Information for the Public » Health Topics » Iron-Deficiency Anemia » What Is ... Iron-Deficiency Anemia ...

88

Ferrous Sulfate (Iron)  

MedlinePLUS

... the iron needed by the body to produce red blood cells. It is used to treat or prevent iron- ... that occurs when the body has too few red blood cells because of pregnancy, poor diet, excess bleeding, or ...

89

Can iron be teratogenic?  

Microsoft Academic Search

Several kinds of evidence indicate that elevated iron during the 3–8 week embryonic (organogenesis) period of human gestation\\u000a may be teratogenic. (1) In the embryonic period, the natural maternal absorption of food iron is 30% below the estimated daily\\u000a iron loss. (2) As compared with maternal serum, embryonic fetal coelomic fluid contains only one-fourth as much iron but nearly\\u000a six times

E. D. Weinberg

2010-01-01

90

Iron Deficiency: Beyond Anemia  

Microsoft Academic Search

Iron deficiency is the most common nutritional disorder affecting at least one third of world’s population. Though anemia\\u000a is common manifestation of iron deficiency, other effects of iron deficiency on various tissues, organs and systems are usually\\u000a under recognized. Impaired brain development and cognitive, behavioural and psychomotor impairment are most worrisome manifestations\\u000a of iron deficiency. Studies have demonstrated that some

Dinesh Yadav; Jagdish Chandra

2011-01-01

91

Iron nutrition in adolescence  

Microsoft Academic Search

Adolescence is an important period of nutritional vulnerability due to increased dietary requirements for growth and development. Iron needs are elevated as a result of intensive growth and muscular development, which implies an increase in blood volume; thus, it is extremely important for the adolescent's iron requirements to be met. Diet, therefore, must provide enough iron and, moreover, nutrients producing

MARTA MESÍAS; ISABEL SEIQUER; M. PILAR NAVARRO

2012-01-01

92

Iron, mycobacteria and tuberculosis  

Microsoft Academic Search

The role of iron in the growth and metabolism of M. tuberculosis and other mycobacteria is discussed in relation to the acquisiton of iron from host sources, such as transferrin, lactoferrin and ferritin, and its subsequent assimilation and utilization by the bacteria. Key components involved in the acquisition of iron (as ferric ion) and its initial transport into the mycobacterial

Colin Ratledge

2004-01-01

93

The Rusting of Iron  

Microsoft Academic Search

SEVERAL letters have appeared in NATURE respecting conditions under which iron rusts. The usually accepted view has been that iron will not rust unless carbonic acid is present. After a very careful investigation of the subject, I was led to the conclusion that provided iron, oxygen, and liquid water are brought together, chemical change takes place with the production of

Wyndham R. Dunstan

1907-01-01

94

Iron losses in sweat  

Microsoft Academic Search

The losses of iron in whole body cell-free sweat were determined in eleven healthy men. A new experimental design was used with a very careful cleaning procedure of the skin and repeated consecutive sampling periods of sweat in a sauna. The purpose was to achieve a steady state of sweat iron losses with minimal influence from iron originating from desquamated

M. Brune; B. Magnusson; H. Persson; L. Hallberg

1986-01-01

95

Iron, radiation, and cancer.  

PubMed Central

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

Stevens, R G; Kalkwarf, D R

1990-01-01

96

Distribution and diversity of gallionella-like neutrophilic iron oxidizers in a tidal freshwater marsh  

Microsoft Academic Search

Microbial iron oxidation is an integral part of the iron redox cycle in wetlands. Nonetheless, relatively little\\u000ais known about the composition and ecology of iron-oxidizing communities in the soils and sediments of\\u000awetlands. In this study, sediment cores were collected across a freshwater tidal marsh in order to characterize\\u000athe iron-oxidizing bacteria (FeOB) and to link their distributions to

J. Wang; S. Vollrath; T. Behrends; P. L. E. Bodelier; G. Muyzer; F. Den Oudsten; M. Meima-Franke; P. Cappellen; H. J. Laanbroek

2011-01-01

97

Distribution and diversity of Gallionella-like neutrophilic iron oxidizers in a tidal freshwater marsh  

Microsoft Academic Search

Microbial iron oxidation is an integral part of the iron redox cycle in wetlands. Nonetheless, relatively little is known about the composition and ecology of iron-oxidizing communities in the soils and sediments of wetlands. In this study, sediment cores were collected across a freshwater tidal marsh in order to characterize the iron-oxidizing bacteria (FeOB) and to link their distributions to

J. Wang; S. Vollrath; T. Behrends; P. L. E. Bodelier; G. Muyzer; M. Meima-Franke; F. den Oudsten; P. Van Cappellen; H. J. Laanbroek

2011-01-01

98

Iron and thrombosis  

PubMed Central

Although essential for cell physiology, an increase or depletion of body iron has harmful effects on health. Apart from iron deficiency anemia and iron overload-related organ tissue damage, there are increasing evidences that body iron status is implicated in atherosclerotic cardiovascular diseases. The hypothesis formulated in 1981 that iron depletion may protect against cardiovascular events is intriguing and has generated a significant debate in the last two decades. Indeed, to study this phenomenon, several investigators have tried to design appropriate experimental and clinical studies and to identify useful biochemical and genetic markers of iron status. The results of the literature on the effect of iron deficiency and overload on vascular health are critically reviewed in this study from a pathogenic and clinical point of view.

Targher, Giovanni; Montagnana, Martina; Lippi, Giuseppe

2007-01-01

99

A role for tumour necrosis factor ? in human small bowel iron transport  

PubMed Central

Cytokines are integral to the development of anaemia of chronic inflammation. Cytokines modulate hepcidin expression and iron sequestration by the reticuloendothelial system but their direct effects on small bowel iron transport are not well characterized. The aim of the present study was to examine the local effects of TNF? (tumour necrosis factor ?) on small bowel iron transport and on iron transporter expression in the absence of hepcidin. The effects of TNF? on iron transport were determined using radiolabelled iron in an established Caco-2 cell model. The effect of TNF? on the expression and localization of the enterocyte iron transporters DMT-1 (divalent metal transporter 1), IREG-1 (iron-regulated transporter 1) and ferritin was determined utilizing Caco-2 cells and in a human ex vivo small bowel culture system. TNF? mediated an early induction in both iron import and iron export, which were associated with increased DMT-1 and IREG-1 mRNA and protein expression (P<0.05). However, by 24 h, both iron import and iron export were significantly inhibited, coinciding with an induction of ferritin heavy chain (P<0.05) and a decrease in DMT-1 and IREG-1 to baseline levels. In addition, there was a relocalization of IREG-1 away from the basolateral cell border and increased iron deposition in villous enterocytes. In conclusion, TNF? has a direct effect on small bowel iron transporter expression and function, leading to an inhibition of iron transport.

2005-01-01

100

Case studies: iron1234  

PubMed Central

Iron biomarkers were developed to define the size of iron stores and the adequacy of the iron supply required to meet functional needs. Approximately 80% of the iron delivered to tissues through the circulating plasma pool will be incorporated into hemoglobin. Consequently, with the exception of serum ferritin, iron biomarkers are measures of iron sufficiency for erythrocyte production. They have proven to be very valuable in the determination of the cause of anemia in the clinical setting in which additional information about factors that affect the patient's health is available. However, all current biomarkers are affected by factors other than iron status, which limit their utility for the determination of the prevalence of iron deficiency in some populations, particularly in populations who live in developing countries. Furthermore, relations between iron status and functional outcomes such as neonatal and infant mortality; motor, cognitive, and emotional development in infants; and severe morbidity from malaria in young children are inadequately characterized. There is a need to identify and standardize biomarkers that have the highest predictive value for specific functional outcomes in each setting. The most appropriate biomarkers may vary with the setting and be influenced by age, sex, gestational stage of pregnancy, and environmental factors such as repeated or chronic infections. There is also an urgent need for improved technology to permit the use of specific biomarkers in field studies in resource-poor regions. Finally, more research is required to define the potential role of hepcidin and non–transferrin-bound iron assays.

Lynch, Sean

2011-01-01

101

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

2011-11-03

102

Energy and materials flows in the fabrication of iron and steel semifinished products  

Microsoft Academic Search

The flow of energy and materials in the fabrication of iron and steel semifinished products from molten metal is discussed. The focus is on techniques to reduce the amount of energy required to produce the typical products of integrated steel plants and iron and steel foundries. In integrated steel plants, if only 50% of the steel being cast were continuously

J. B. Jr. Darby; R. M. Arons

1979-01-01

103

Human Iron-Sulfur Cluster Assembly, Cellular Iron Homeostasis, and Disease†  

PubMed Central

Iron?sulfur (Fe?S) proteins contain prosthetic groups consisting of two or more iron atoms bridged by sulfur ligands, which facilitate multiple functions, including redox activity, enzymatic function, and maintenance of structural integrity. More than 20 proteins are involved in the biosynthesis of iron?sulfur clusters in eukaryotes. Defective Fe?S cluster synthesis not only affects activities of many iron?sulfur enzymes, such as aconitase and succinate dehydrogenase, but also alters the regulation of cellular iron homeostasis, causing both mitochondrial iron overload and cytosolic iron deficiency. In this work, we review human Fe?S cluster biogenesis and human diseases that are caused by defective Fe?S cluster biogenesis. Fe?S cluster biogenesis takes place essentially in every tissue of humans, and products of human disease genes, including frataxin, GLRX5, ISCU, and ABCB7, have important roles in the process. However, the human diseases, Friedreich ataxia, glutaredoxin 5-deficient sideroblastic anemia, ISCU myopathy, and ABCB7 sideroblastic anemia/ataxia syndrome, affect specific tissues, while sparing others. Here we discuss the phenotypes caused by mutations in these different disease genes, and we compare the underlying pathophysiology and discuss the possible explanations for tissue-specific pathology in these diseases caused by defective Fe?S cluster biogenesis.

2010-01-01

104

Iron-Fortified Infant Cereals  

Microsoft Academic Search

Infants are particularly susceptible to iron deficiency and related anemia due to their high growth rates and the low iron content of breast milk and most unfortified weaning foods. Cows' milk also is poor in iron, and certain forms of cows' milk cause blood and thus iron loss from the gastrointestinal tract. Iron-fortified cereal-based complementary foods – infant cereals –

Richard C. Theuer

2008-01-01

105

Iron metabolism in mammalian cells  

Microsoft Academic Search

Most living things require iron to exist. Iron has many functions within cells but is rarely found unbound because of its propensity to catalyze the formation of toxic free radicals. Thus the regulation of iron requirements by cells and the acquisition and uptake of iron into tissues in multicellular organisms is tightly regulated. In humans, understanding iron transport and utility

Brandie L Walker; Jacqueline W. C Tiong; Wilfred A Jefferies

2001-01-01

106

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

107

Iron Deficiency Anemia  

Microsoft Academic Search

The prevalence of iron deficiency anemia is 2 percent in adult men, 9 to 12 percent in non-Hispanic white women, and nearly 20 percent in black and Mexican-American women. Nine percent of patients older than 65 years with iron deficiency anemia have a gastrointestinal cancer when evaluated. The U.S. Preventive Services Task Force currently recommends screening for iron deficiency anemia

SHERSTEN KILLIP; JOHN M. BENNETT; MARA D. CHAMBERS

108

Iron Dynamics in Plants  

Microsoft Academic Search

Iron dynamics in plants start by complex interactions between plants and the rhizospheric microflora, which determine the amount of available iron for uptake by root transporters. Under iron?deficient conditions, two types of high affinity transport systems are activated, depending on the plant family considered. In nongrass plants, Fe(III)?chelate reduction is followed by Fe(II) uptake, whereas in grasses, Fe(III) chelated to

2007-01-01

109

Reactivity of Iron  

NSDL National Science Digital Library

In this laboratory excercise, students will be introduced to the oxidation / corrosion of iron from two different sources (flame and water). From the examination of corrosion from multiple sources, students will be able to compare and contrast the effects each has on the iron samples. Students will also be able to observe the effect of various material processing techniques has on the corrosive properties of iron.

Stoebe, Thomas G.

2008-10-28

110

Iron oxide modified minerals  

Microsoft Academic Search

Composites of iron oxide nanoparticles immobilized on the surface of various clay mineral matrices (muscovite, montmorillonite\\u000a and vermiculite) have been prepared by the alkaline oxidative hydrolysis of iron sulphate in the presence of mineral matrices.\\u000a The composites have been studied by Mössbauer spectroscopy, XRD, TEM and SQUID. Correspondence between the hyperfine parameters\\u000a and the iron oxide particle size and magnetic

M. Mashlan; H. Bartonkova; D. Jancik; J. Tucek; P. Martinec

111

Iron oxide modified minerals  

Microsoft Academic Search

Composites of iron oxide nanoparticles immobilized on the surface of various clay mineral matrices (muscovite, montmorillonite\\u000a and vermiculite) have been prepared by the alkaline oxidative hydrolysis of iron sulphate in the presence of mineral matrices.\\u000a The composites have been studied by Mössbauer spectroscopy, XRD, TEM and SQUID. Correspondence between the hyperfine parameters\\u000a and the iron oxide particle size and magnetic

M. Mashlan; H. Bartonkova; D. Jancik; J. Tucek; P. Martinec

2009-01-01

112

Plea for Iron Astrochemistry  

SciTech Connect

Iron is a key element and compound in living bodies. It is the most abundant refractory element and has the most stable nucleus in the Universe. Also, elemental Iron has a relevant abundance in the interstellar medium and dense clouds, it can be in gas phase or included in dust particles. During this talk, I shall explain why this special interest in Iron and shall give a brief explanation about its origin and the interstellar nucleosynthesis. After this I'll detail the rich chemistry that Iron can be involved in the interstellar medium, dense clouds with several species.

Mostefaoui, T. A.; Benmerad, B.; Kerkar, M. [Faculte des Sciences Exactes, Targa ou Zemmour, Universite de A. Mira, 6000 Bejaiea (Algeria)

2010-10-31

113

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

114

Micromanaging Iron Homeostasis  

PubMed Central

Iron is fundamental for sustaining life for living organisms, and the iron metabolism is finely regulated at different levels. In cancer cells, deregulation of the iron metabolism induces oxidative stress and drives tumor progression and metastasis; however, the molecular mechanisms of iron homeostasis are not fully understood. Here we found that iron deficiency as well as hypoxia promoted microRNA-210 (miR-210) expression. A central mediator of miR-210 transcriptional activation is the hypoxia-inducible factor (HIF)-1?, and the hypoxia-response element in the miR-210 promoter is confirmed experimentally. This is in agreement with the data from in vivo studies that have demonstrated the presence of miR-210-expressing cells at the chronic hypoxic regions of xenografted tumors. Furthermore we found two essential molecules for iron homeostasis, iron-sulfur cluster scaffold protein (ISCU) and transferrin receptor 1 (TfR), are a direct target of miR-210. Transfection of miR-210 decreases the uptake of transferrin by inhibiting the expression of TfR. In addition, inhibition of miR-210 by anti-miR-210 up-regulates ISCU expression. These findings suggest that miR-210 works as an iron sensor and is involved in the maintenance of iron homeostasis by sustaining the TfR expression level to stimulate cell proliferation and promote cell survival in the hypoxic region within tumors.

Yoshioka, Yusuke; Kosaka, Nobuyoshi; Ochiya, Takahiro; Kato, Takashi

2012-01-01

115

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

116

Regulation of iron pathways in response to hypoxia.  

PubMed

Constituting an integral part of a heme's porphyrin ring, iron is essential for supplying cells and tissues with oxygen. Given tight links between oxygen delivery and iron availability, it is not surprising that iron deprivation and oxygen deprivation (hypoxia) have very similar consequences at the molecular level. Under hypoxia, the expression of major iron homeostasis genes including transferrin, transferrin receptor, ceruloplasmin, and heme oxygenase-1 is activated by hypoxia-inducible factors to provide increased iron availability for erythropoiesis in an attempt to enhance oxygen uptake and delivery to hypoxic cells. Iron-response proteins (IRP1 and IRP2) and "cap-n-collar" bZIP transcriptional factors (NE-F2 p45; Nrf1, 2, and 3; Bach1 and 2) also control gene and protein expression of the key iron homeostasis proteins. In this article, we give an overview of the mechanisms by which iron pathways are regulated by hypoxia at multiple levels. In addition, potential clinical benefits of manipulating iron pathways in the hypoxia-related conditions anemia and ischemia are discussed. PMID:21185934

Chepelev, Nikolai L; Willmore, William G

2010-12-24

117

Brain iron homeostasis.  

PubMed

Iron is essential for virtually all types of cells and organisms. The significance of the iron for brain function is reflected by the presence of receptors for transferrin on brain capillary endothelial cells. The transport of iron into the brain from the circulation is regulated so that the extraction of iron by brain capillary endothelial cells is low in iron-replete conditions and the reverse when the iron need of the brain is high as in conditions with iron deficiency and during development of the brain. Whereas there is good agreement that iron is taken up by means of receptor-mediated uptake of iron-transferrin at the brain barriers, there are contradictory views on how iron is transported further on from the brain barriers and into the brain extracellular space. The prevailing hypothesis for transport of iron across the BBB suggests a mechanism that involves detachment of iron from transferrin within barrier cells followed by recycling of apo-transferrin to blood plasma and release of iron as non-transferrin-bound iron into the brain interstitium from where the iron is taken up by neurons and glial cells. Another hypothesis claims that iron-transferrin is transported into the brain by means of transcytosis through the BBB. This thesis deals with the topic "brain iron homeostasis" defined as the attempts to maintain constant concentrations of iron in the brain internal environment via regulation of iron transport through brain barriers, cellular iron uptake by neurons and glia, and export of iron from brain to blood. The first part deals with transport of iron-transferrin complexes from blood to brain either by transport across the brain barriers or by uptake and retrograde axonal transport in motor neurons projecting beyond the blood-brain barrier. The transport of iron and transport into the brain was examined using radiolabeled iron-transferrin. Intravenous injection of [59Fe-125]transferrin led to an almost two-fold higher accumulation of 59Fe than of [125I]transferrin in the brain. Some of the 59Fe was detected in CSF in a fraction less than 30 kDa (III). It was estimated that the iron-binding capacity of transferrin in CSF was exceeded, suggesting that iron is transported into the brain in a quantity that exceeds that of transferrin. Accordingly, it was concluded that the paramount iron transport across the BBB is the result of receptor-mediated endocytosis of iron-containing transferrin by capillary endothelial cells, followed by recycling of transferrin to the blood and transport of non-transferrin-bound iron into the brain. It was found that retrograde axonal transport in a cranial motor nerve is age-dependent, varying from almost negligible in the neonatal brain to high in the adult brain. The principle sources of extracellular transferrin in the brain are hepatocytes, oligodendrocytes, and the choroid plexus. As the passage of liver-derived transferrin into the brain is restricted due to the BBB, other candidates for binding iron in the interstitium should be considered. In vitro studies have revealed secretion of transferrin from the choroid plexus and oligodendrocytes. The second part of the thesis encompasses the circulation of iron in the extracellular fluids of the brain, i.e. the brain interstitial fluid and the CSF. As the latter receives drainage from the interstitial fluid, the CSF of the ventricles can be considered a mixture of these fluids, which may allow for analysis of CSF in matters that relate to the brain interstitial fluid. As the choroid plexus is known to synthesize transferrin, a key question is whether transferrin of the CSF might play a role for iron homeostasis by diffusing from the ventricles and subarachnoid space to the brain interstitium. Intracerebroventricular injection of [59Fe125I]transferrin led to a higher accumulation of 59Fe than of [125I]transferrin in the brain. Except for uptake and axonal transport by certain neurons with access to the ventricular CSF, both iron and transferrin were, however, restricted to areas situated in close proximity to the ventric

Moos, Torben

2002-11-01

118

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

Code of Federal Regulations, 2013 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...

2013-04-01

119

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

Code of Federal Regulations, 2010 CFR

...Remedial measures: Cast iron and ductile iron pipelines. 192.489 Section...Remedial measures: Cast iron and ductile iron pipelines. (a) General graphitization... Each segment of cast iron or ductile iron pipe on which general...

2010-10-01

120

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

Code of Federal Regulations, 2010 CFR

...Remedial measures: Cast iron and ductile iron pipelines. 192.489 Section...Remedial measures: Cast iron and ductile iron pipelines. (a) General graphitization... Each segment of cast iron or ductile iron pipe on which general...

2009-10-01

121

Nonhematological Benefits of Iron  

Microsoft Academic Search

Iron deficiency anemia is common in people with chronic kidney disease (CKD) and its importance in supporting erythropoiesis is unquestioned especially in those patients treated with erythropoietin. Clinical symptomatology such as fatigability, cold intolerance, failure to concentrate and poor effort intolerance is often attributed to anemia or uremia. That iron deficiency, per se, can cause these symptoms is poorly recognized.

Rajiv Agarwal

2007-01-01

122

RED Facts: Iron Salts.  

National Technical Information Service (NTIS)

When a pesticide is eligible for reregistration, EPA announces this and explains why in a Reregistration Eligibility Document, or RED. The fact sheet summarizes the information in the RED for iron salts. The iron salts consist of three pesticide active in...

1993-01-01

123

Iron Absorption from Maize  

Microsoft Academic Search

The present study was performed to measure the effect of increasing amounts of ascorbic acid on the absorption of 5 mg iron in a maize meal. 30 normal subjects were served two maize meals, one of them with ascorbic acid at different dose levels. At the dose level of 200 mg ascorbic acid there was a sixfold increase in iron

Erik Björn-Rasmussen; Leif Hallberg

1974-01-01

124

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

125

The Rusting of Iron  

Microsoft Academic Search

IN my remarks on ``The Rusting of Iron,'' published in NATURE of September 27, I directed attention to the fact that pure hydrogen peroxide solution was rapidly decomposed by cast-iron, the latter becoming covered with rust. This, I stated, ``was, no doubt, due to catalytic action.''

J. Newton Friend

1906-01-01

126

Reregistration Eligibility Document (RED): Iron Salts.  

National Technical Information Service (NTIS)

The iron salts consist of three pesticide active ingredients that are eligible for reregistration: Iron (III) sulfate, Iron (II) sulfate monohydrate, and Iron (II) sulfate heptahydrate. Iron salts are registered for use as herbicides to control moss on la...

1993-01-01

127

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

128

Iron Status in Newborns Born to Iron-Deficient Mothers  

Microsoft Academic Search

Background: Iron deficiency anemia is one of the important prob- lems during pregnancy. Iron deficiency has several adverse effects on pregnant women and their newborns. Objective: To determine the status of iron store in newborns born to mothers with iron deficiency anemia. Methods: In a cross-sectional study, 90 mothers were categorized into three groups according to their pre-delivery hemoglobin and

S. Ziaei

2003-01-01

129

Molecular control of vertebrate iron homeostasis by iron regulatory proteins  

PubMed Central

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

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

2008-01-01

130

Erythropoiesis, iron metabolism and iron supplementation during erythropoietin therapy  

Microsoft Academic Search

\\u000a Knowledge gained regarding the relationship between erythropoietin, iron, and erythropoiesis in patients with anemia undergoing\\u000a recombinant human erythropoietin therapy (EPO) has implications for patient management. During EPO therapy, iron restricted\\u000a erythropoiesis is evident even in the presence of storage iron and oral iron supplementation. Intravenous iron therapy in\\u000a renal dialysis patients undergoing EPO therapy can produce hematological responses in patients

Lawrence T. Goodnough

131

Iron deficiency anemia and educational  

Microsoft Academic Search

The present study investigates the effect of iron supplementation on measures of school performance among 78 iron-deficient anemic and 41 nonanemic children in an economically deprived rural area in Central Java, Indonesia. All the subjects were treated forancylostomiasis before iron supplementation. They were randomly assigned to either an iron or placebo group. Hematological and behavioral measurements were obtained immediately before

AG Soemantri; Ernesto Pollitt; Insun Kim

1985-01-01

132

Enzymes of respiratory iron oxidation  

Microsoft Academic Search

This report focuses on the progress made in three areas of research concerned with enzymes involved in respiratory iron oxidation. The three areas are as follows: development of an improved procedure for the routine large scale culture of iron oxidizing chemolithotrophs based on the in-situ electrolysis of the soluble iron in the growth medium; to perform iron oxidation kinetic studies

Blake; R. II

1991-01-01

133

Iron in Cereal  

NSDL National Science Digital Library

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

Mid-continent Research for Education and Learning (McREL); Jacobs, Steve

2004-01-01

134

Synthesis and Characterization of Iron(II) Quinaldate Complexes  

PubMed Central

Treatment of iron(II) chloride or iron(II) bromide with two equivalents of sodium quinaldate (qn = quinaldate or C10H6NO2?) yields the coordinatively unsaturated mononuclear iron(II) quinaldate complexes Na[FeII(qn)2Cl]·DMF and Na[FeII(qn)2Br]·DMF, respectively. When a similar synthesis is carried out using iron(II) triflate, a solvent derived linear tri-iron(II) complex, [FeII3(qn)6(DMF)2], with two five-coordinate iron(II) centers and a single six-coordinate iron(II) center is obtained. Each of these species has been characterized using X-ray diffraction. The vibrational features of these complexes are consistent with the observed solid state structures. Each of these compounds exhibits an iron(II)-to-quinaldate(?*) charge-transfer band between 520-550 nm. These metal-to-ligand charge-transfer bands are sensitive to substitution of the quinaldates as well as alteration of the first coordination sphere ligands. However, the 1H NMR spectra of these paramagnetic high-spin iron(II) complexes are not consistent with retention of the solid state structures in DMF solution. The chemical shifts, longitudinal relaxation times (T1), relative integrations, and substitution of the quinaldate ligands provide a means to fully assign the 1H NMR spectra of the paramagnetic materials. These spectra are consistent with coordination equilibria between five-and six-coordinate species in DMF solution. Electrochemical studies are reported to place these oxygen-sensitive compounds in a broader context with other iron(II) compounds. Iron complexes of bidentate quinoline-2-carboxylate derived ligands are germane to metabolic pathways, environmental remediation, as well as to catalytic applications.

Houghton, Dylan T.; Gydesen, Nicholas W.; Arulsamy, Navamoney; Mehn, Mark P.

2010-01-01

135

Plant Cell Nucleolus as a Hot Spot for Iron*  

PubMed Central

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

Roschzttardtz, Hannetz; Grillet, Louis; Isaure, Marie-Pierre; Conejero, Genevieve; Ortega, Richard; Curie, Catherine; Mari, Stephane

2011-01-01

136

Plant cell nucleolus as a hot spot for iron.  

PubMed

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

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

2011-06-30

137

Isocitrate ameliorates anemia by suppressing the erythroid iron restriction response.  

PubMed

The unique sensitivity of early red cell progenitors to iron deprivation, known as the erythroid iron restriction response, serves as a basis for human anemias globally. This response impairs erythropoietin-driven erythropoiesis and underlies erythropoietic repression in iron deficiency anemia. Mechanistically, the erythroid iron restriction response results from inactivation of aconitase enzymes and can be suppressed by providing the aconitase product isocitrate. Recent studies have implicated the erythroid iron restriction response in anemia of chronic disease and inflammation (ACDI), offering new therapeutic avenues for a major clinical problem; however, inflammatory signals may also directly repress erythropoiesis in ACDI. Here, we show that suppression of the erythroid iron restriction response by isocitrate administration corrected anemia and erythropoietic defects in rats with ACDI. In vitro studies demonstrated that erythroid repression by inflammatory signaling is potently modulated by the erythroid iron restriction response in a kinase-dependent pathway involving induction of the erythroid-inhibitory transcription factor PU.1. These results reveal the integration of iron and inflammatory inputs in a therapeutically tractable erythropoietic regulatory circuit. PMID:23863711

Richardson, Chanté L; Delehanty, Lorrie L; Bullock, Grant C; Rival, Claudia M; Tung, Kenneth S; Kimpel, Donald L; Gardenghi, Sara; Rivella, Stefano; Goldfarb, Adam N

2013-07-25

138

Ferritin Iron Absorption in Man  

Microsoft Academic Search

The iron absorption from ferntin and hemosiderin biosynthetically labeled with radioiron was studied in 108 subjects. The geometric mean absorption of ferritin iron in both normal and iron-deficient subjects was 1.9%. Its mean absorption ranged from 0.9% in normal subjects to 2.5% in subjects with moderate iron deficiency and 5.7% in subjects with marked iron de- ficiency. The administration of

Miguel Layrisse; Martha Renzy; Irene Leets

1975-01-01

139

Iron Binding Properties of Saliva  

Microsoft Academic Search

GASTRIC juice of healthy people contains a high molecular weight iron binding protein ``gastroferrin''1. A role for the gastric iron binding protein in the regulation of iron absorption has been proposed2,3, and alterations in its production have been described in clinical conditions of iron deficiency3 and iron overload2. The gastric juice obtained for the studies previously reported was free of

Peter L. Reilly; Peter S. Davis; Donald J. Deller

1968-01-01

140

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

141

Development of Iron Aluminides.  

National Technical Information Service (NTIS)

A program was conducted to develop improved iron-aluminide alloys with higher elevated temperature strength and room temperature ductility compared to the baseline Fe3Al alloy. The technical approach involved the screening evaluation of two experimental s...

G. C. Culbertson C. S. Kortovich

1986-01-01

142

Studies of Hypervalent Iron.  

National Technical Information Service (NTIS)

The iron (IV), (V) and (VI) oxidation states are of great interest because of their role in catalytic oxidation/hydroxylation reactions. This report summarizes the information currently available on the kinetic and chemical properties of the water-soluble...

B. H. J. Bielski

1989-01-01

143

An update on iron physiology  

PubMed Central

Iron is an essential micronutrient, as it is required for adequate erythropoietic function, oxidative metabolism and cellular immune responses. Although the absorption of dietary iron (1-2 mg/d) is regulated tightly, it is just balanced with losses. Therefore, internal turnover of iron is essential to meet the requirements for erythropoiesis (20-30 mg/d). Increased iron requirements, limited external supply, and increased blood loss may lead to iron deficiency (ID) and iron-deficiency anemia. Hepcidin, which is made primarily in hepatocytes in response to liver iron levels, inflammation, hypoxia and anemia, is the main iron regulatory hormone. Once secreted into the circulation, hepcidin binds ferroportin on enterocytes and macrophages, which triggers its internalization and lysosomal degradation. Thus, in chronic inflammation, the excess of hepcidin decreases iron absorption and prevents iron recycling, which results in hypoferremia and iron-restricted erythropoiesis, despite normal iron stores (functional ID), and anemia of chronic disease (ACD), which can evolve to ACD plus true ID (ACD + ID). In contrast, low hepcidin expression may lead to iron overload, and vice versa. Laboratory tests provide evidence of iron depletion in the body, or reflect iron-deficient red cell production. The appropriate combination of these laboratory tests help to establish a correct diagnosis of ID status and anemia.

Munoz, Manuel; Villar, Isabel; Garcia-Erce, Jose Antonio

2009-01-01

144

Reinforced iron boride materials  

Microsoft Academic Search

1.An iron boride alloy introduced by infiltration into the pores between molybdenum wires and an iron matrix ensures strong bonding between the wires and the matrix.2.During the manufacture of a RIBM diffusion zone transition layers form around the molybdenum wires. The transition layers consist of variable-composition solid solutions comprising all the elements present in the composite.3.Reinforcement with molybdenum wires substantially

A. E. Mashkov; V. I. Gurdin

1976-01-01

145

The Rusting of Iron  

Microsoft Academic Search

HAS anyone inquired whether the rusting of iron may not be associated with some micro-organisms? The facts that oxygen, water, and carbon dioxide are necessary; that iron does not rust when immersed in boiling water and then sealed up; that certain solutions are said to inhibit rusting (e.g. potassium ferrocyanide, a poison), and that certain other solutions encourage rusting (e.g.

Hugh Richardson

1906-01-01

146

[Iron quantification in iron overload disease using MRI].  

PubMed

Iron as an essential nutrient is involved in multiple metabolic activities. The importance of a sufficient iron supply is stressed by the fact that, according to WHO data, about 30 % of the global population suffers from iron deficiency and resulting anemia. In contrast, hereditary hemochromatosis is the most common monogeneous inherited disease (prevalence of homozygous genotype 1:200 - 300 in Germany). While iron-induced anemia can be handled by relatively simple diagnostic and therapeutic management, the diagnosis and quantification of organ iron overload is far more challenging. This is of great clinical impact, as the overall body and organ iron concentration is the crucial prognostic parameter in iron overload disease. In 2001 the international workshop of NIDDK (National Institute of Diabetes and Digestive and Kidney Diseases) concluded that a quantitative, noninvasive, safe, and accurate approach for the assessment of body iron storage is needed to improve the diagnosis and management of patients with iron overload. PMID:23450372

Schönnagel, B P; Fischer, R; Nielsen, P; Grosse, R; Adam, G; Yamamura, J

2013-02-28

147

Iron-deficiency anaemia.  

PubMed

Iron-deficiency anaemia (IDA) is a common clinical problem throughout the world and an enormous public health problem in developing countries. The cornerstone of the laboratory identification of IDA is a low haemoglobin and serum ferritin concentration although a normal serum ferritin does exclude IDA. When the serum ferritin is normal in an anaemic patient with iron-deficient erythropoiesis, it is common practise to perform a bone marrow examination to diagnose IDA. The recent introduction of serum transferrin receptor measurements is a useful alternative for distinguishing IDA from the anaemia of chronic disease because the serum receptor concentration is usually elevated in patients with IDA but normal in patients with anaemia due to inflammation or neoplasia. It is helpful for the clinican to be aware of the causes of physiological IDA. The most important are increased rate of body growth, excessive menstrual blood loss, pregnancy, regular blood donation, intensive endurance training, chronic aspirin use and a vegetarian diet. Without these, a careful search for unsuspected gastrointestinal blood loss must be made and even when the suspicion of physiological IDA is high, it is prudent to screen for fecal occult blood. In most patients, IDA responds promptly to oral iron therapy. Patients who experience troublesome side-effects with oral iron might benefit from a gastric delivery system for oral iron which eliminates nausea and vomiting and improves iron absorption when given with food.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7881154

Cook, J D

1994-12-01

148

Iron-activated iron uptake: A positive feedback loop mediated by iron regulatory protein 1  

Microsoft Academic Search

The love-hate relationship between iron and living matter has generated mechanisms to maintain iron concentration in a narrow range, above and below which deleterious effects occur. At the cellular level, iron homeostasis is accomplished by the activity of the IRP proteins, which, under conditions of iron depletion, up-regulate the expression of the iron acquisition proteins TfR and DMT1. It has

Marto T. Núñez; Claudia Núñez-Millacura; Victoria Tapia; Patricia Muñoz; Dora Mazariegos; Miguel Arredondo; Pablo Muñoz; Casilda Mura; Ricardo B. Maccioni

2003-01-01

149

[Iron metabolism and maternal-fetal iron circulation].  

PubMed

Iron is an essential micronutrient for the proper functioning of most organisms. This element is used in oxygen transport, myelin and neurotransmitters synthesis, cell cycle and synthesis of nucleic acids. The importance of iron in the maturation of lymphocytes and proper functioning of the eye is also stressed. Newborns are particularly sensitive to imbalances in iron metabolism. Iron deficiency during pregnancy carries serious clinical consequences. It seems that a key role in the transport of iron between mother and fetus is plays by hepcidin and, described in 2010 zyklopen. The physiological role of proteins involved in iron metabolism and transport of this metal by the placenta are described in this paper.  PMID:23175344

S?omka, Artur; Zekanowska, Ewa; Piotrowska, Katarzyna; Kwapisz, Justyna

2012-11-16

150

Protein Degradation and Iron Homeostasis  

PubMed Central

Regulation of both systemic and cellular iron homeostasis requires the capacity to sense iron levels and appropriately modify the expression of iron metabolism genes. These responses are coordinated through the efforts of several key regulatory factors including F-box and Leucine-rich Repeat Protein 5 (FBXL5), Iron Regulatory Proteins (IRPs), Hypoxia Inducible Factor (HIF), and ferroportin. Notably, the stability of each of these proteins is regulated in response to iron. Recent discoveries have greatly advanced our understanding of the molecular mechanisms governing iron-sensing and protein degradation within these pathways. It has become clear that iron’s privileged roles in both enzyme catalysis and protein structure contribute to its regulation of protein stability. Moreover, these multiple pathways intersect with one another in larger regulatory networks to maintain iron homeostasis.

Thompson, Joel W.; Bruick, Richard K.

2013-01-01

151

Sphingolipid Signaling Mediates Iron Toxicity  

PubMed Central

Summary Iron constitutes a major source of toxicity due to its ability to generate reactive oxygen species that can damage cellular macromolecules. However the precise mechanism by which exposure to high iron concentrations results in cellular toxicity remains unknown. Here we identify sphingolipid synthesis and signaling as a major mediator of iron toxicity in S. cerevisiae. Inhibition of sphingolipid synthesis by myriocin treatment or after overexpression of the negative regulator Orm2p confers resistance to high iron. High iron conditions upregulate sphingolipid synthesis, and increasing sphingolipid levels by inactivating Orm2p exacerbates sensitivity to iron. Toxicity is mediated by sphingolipid signaling, as inactivation of the sphingolipid-activated protein kinases Pkh1p and Ypk1p and of the transcription factor Smp1p also enhances resistance to high iron conditions. These results demonstrate an unexpected connection between sphingolipid flux and iron toxicity, and show that activation of a signal transduction cascade contributes to iron-mediated cellular toxicity.

Lee, Yueh-Jung; Huang, Xinhe; Kropat, Janette; Henras, Anthony; Merchant, Sabeeha S; Dickson, Robert C; Chanfreau, Guillaume F.

2012-01-01

152

Sphingolipid signaling mediates iron toxicity.  

PubMed

Iron constitutes a major source of toxicity due to its ability to generate reactive oxygen species that can damage cellular macromolecules. However, the precise mechanism by which exposure to high iron concentrations results in cellular toxicity remains unknown. Here we identify sphingolipid synthesis and signaling as a major mediator of iron toxicity in S. cerevisiae. Inhibition of sphingolipid synthesis by myriocin treatment or after overexpression of the negative regulator Orm2p confers resistance to high iron. High iron conditions upregulate sphingolipid synthesis, and increasing sphingolipid levels by inactivating Orm2p exacerbates sensitivity to iron. Toxicity is mediated by sphingolipid signaling, as inactivation of the sphingolipid-activated protein kinases Pkh1p and Ypk1p and of the transcription factor Smp1p also enhances resistance to high iron conditions. These results demonstrate an unexpected connection between sphingolipid flux and iron toxicity and show that activation of a signal transduction cascade contributes to iron-mediated cellular toxicity. PMID:22768841

Lee, Yueh-Jung; Huang, Xinhe; Kropat, Janette; Henras, Anthony; Merchant, Sabeeha S; Dickson, Robert C; Chanfreau, Guillaume F

2012-07-01

153

Iron absorption in Drosophila melanogaster.  

PubMed

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. PMID:23686013

Mandilaras, Konstantinos; Pathmanathan, Tharse; Missirlis, Fanis

2013-05-17

154

MR characterization of hepatic storage iron in transfusional iron overload.  

PubMed

PURPOSE: To quantify the two principal forms of hepatic storage iron, diffuse, soluble iron (primarily ferritin), and aggregated, insoluble iron (primarily hemosiderin) using a new MRI method in patients with transfusional iron overload. MATERIALS AND METHODS: Six healthy volunteers and 20 patients with transfusion-dependent thalassemia syndromes and iron overload were examined. Ferritin- and hemosiderin-like iron were determined based on the measurement of two distinct relaxation parameters: the "reduced" transverse relaxation rate, RR2 , and the "aggregation index," A, using three sets of Carr-Purcell-Meiboom-Gill (CPMG) datasets with different interecho spacings. Agarose phantoms, simulating the relaxation and susceptibility properties of tissue with different concentrations of dispersed (ferritin-like) and aggregated (hemosiderin-like) iron, were used for validation. RESULTS: Both phantom and in vivo human data confirmed that transverse relaxation components associated with the dispersed and aggregated iron could be separated using the two-parameter (RR2 , A) method. The MRI-determined total hepatic storage iron was highly correlated (r?=?0.95) with measurements derived from biopsy or biosusceptometry. As total hepatic storage iron increased, the proportion stored as aggregated iron became greater. CONCLUSION: This method provides a new means for noninvasive MRI determination of the partition of hepatic storage iron between ferritin and hemosiderin in iron overload disorders. J. Magn. Reson. Imaging 2013;. © 2013 Wiley Periodicals, Inc. PMID:23720394

Tang, Haiying; Jensen, Jens H; Sammet, Christina L; Sheth, Sujit; Swaminathan, Srirama V; Hultman, Kristi; Kim, Daniel; Wu, Ed X; Brown, Truman R; Brittenham, Gary M

2013-05-29

155

Influence of Solute Additions on the Fracture Behaviour of Armco Iron  

Microsoft Academic Search

The influence of solutes, namely cobalt, molybdenum, nickel and silicon, on the deformation and fracture behaviour of Armco iron has been studied. The J-integral method was used for the measurement of ductile initiation fracture toughness JIC. Although cobalt is seen to enhance significantly JIC of the starting material (Armco iron), molybdenum, nickel and silicon are observed to have a deleterious

M. Srinivas; G. Malakondaiah; P. Rama Rao

1994-01-01

156

Impacts of an Iron and Steel Plant on Residential Property Values  

Microsoft Academic Search

The hedonic price method is used to estimate the relationship between residential property values and proximity to an integrated iron and steel plant located in the outskirts of Gijón, a city in the north of Spain. Empirical results suggest that there is a statistically significant negative relationship between housing values and the distance from the iron and steel plant. From

Celia Bilbao-Terol

2009-01-01

157

Optimum arrangement for the neutron dose rate of an iron-polyethylene shielding system  

SciTech Connect

Integral shielding experiments using iron-polyethylene slab shields were carried out to determine an optimum arrangement for the neutron dose rate. The total thickness of the iron slabs was fixed at 32 cm, while several thicknesses of polyethylene slabs were employed as a parameter. Some measured data were analyzed by the Mone Carlo code MORSE-CG with the splitting technique.

Ueki, K.; Namito, Y.

1987-05-01

158

Mammalian iron metabolism and its control by iron regulatory proteins?  

PubMed Central

Cellular iron homeostasis is maintained by iron regulatory proteins 1 and 2 (IRP1 and IRP2). IRPs bind to iron-responsive elements (IREs) located in the untranslated regions of mRNAs encoding protein involved in iron uptake, storage, utilization and export. Over the past decade, significant progress has been made in understanding how IRPs are regulated by iron-dependent and iron-independent mechanisms and the pathological consequences of IRP2 deficiency in mice. The identification of novel IREs involved in diverse cellular pathways has revealed that the IRP–IRE network extends to processes other than iron homeostasis. A mechanistic understanding of IRP regulation will likely yield important insights into the basis of disorders of iron metabolism. This article is part of a Special Issue entitled: Cell Biology of Metals.

Anderson, Cole P.; Shen, Lacy; Eisenstein, Richard S.; Leibold, Elizabeth A.

2013-01-01

159

Iron or iron oxide grains in the interstellar medium?  

NASA Astrophysics Data System (ADS)

Iron grains have often been proposed as a component of circumstellar and interstellar grains. It is apparent that 'cosmic abundance' circumstellar shells should condense iron-rich particles such as metallic iron, iron/nickel alloys and iron carbides. It is not, however, clear that these grains can survive in this state in the interstellar medium. In this paper the chemistry of iron particles in the diffuse interstellar medium is examined and it is concluded that these grains cannot survive as pristine metallic iron-rich entities. The reactivity of iron, and in particular its reaction with interstellar gas-phase oxygen and sulphur species, will result in the rapid degradation of the metal to an oxide, sulphide or even sulphate. The lack of metallic phases in the mineralogy of primitive interplanetary dust particles is consistent with the absence of metallic particles in the interstellar medium.

Jones, A. P.

1990-07-01

160

Iron metabolism: The low-molecular-mass iron pool  

Microsoft Academic Search

Summary This review examines various aspects of iron metabolism in mammalian and bacterial cells which support the hypothesis of the existence and the biological significance of an intracellular pool of low-molecular mass iron complexes.

M. Fontecave; J. L. Pierre

1991-01-01

161

Formation and occurrence of biogenic iron-rich minerals  

NASA Astrophysics Data System (ADS)

Iron cycling in the Earth's crust depends on redox reactions, which often trigger the precipitation and dissolution of Fe-rich minerals. Microbial activity is also an integral part of iron cycling, through carbon fixation, respiration and passive sorption reactions. Iron oxides formed in close association with bacteria (either as internal or external precipitates) are referred to as biogenic minerals. They form in several types of environments on Earth, from freshwater to marine systems, aquifers, soils and mining impacted systems. Biogenic iron oxides generally occur as nanocrystals and show a wide range of morphology and mineralogy. These minerals form as a result of the direct metabolic activity of bacteria or as a result of passive sorption and nucleation reactions. The metabolic activity of acidophilic and neutrophilic iron-oxidizing bacteria under oxic conditions promotes the oxidation of Fe(II) to Fe(III) and the precipitation of biogenic iron oxides as extracellular precipitates near or on the bacterial cells. Iron oxidation under anoxic conditions can also occur, as a result of the activity of nitrate-reducers and photoautotrophic bacteria using Fe(II) as an electron donor. Secondary Fe-oxide formation has been reported during the microbial reduction of iron oxides. Passive Fe sorption and nucleation onto bacterial cell walls represents another important mechanism leading to iron oxide formation. The surface reactivity of the bacterial surface under environmental pH conditions confers a net negative charge to the cell wall, which leads to the binding of soluble iron and eventually to the precipitation of iron oxides under saturation conditions. Extracellular polymers produced by bacteria can act as a template for iron sorption and Fe-oxide nucleation. Intracellular iron oxide formation has been observed in natural environments. Magnetotactic bacteria produce intracellular magnetosomes, occurring as chains of magnetite crystals within the cells, and an unidentified iron-rich mineral phase forms inside Shewanella cells during the anaerobic reduction of ferrihydrite. Several studies have clearly shown that biogenic iron oxides form in present-day environments, but they might also be important components of ancient geological formations, such as banded-iron formations (BIF). BIF formation is still being debated, but there is now strong evidence that bacteria, more specifically, phototrophic iron oxidizers and possibly iron reducers might have been involved. Biogenic iron oxides represent a potential tool in the search for past and present life on Earth and other planetary systems. Despite the promising use of Fe-isotopes and magnetosomes, there is still no clear proof that they can form only as a result of biological activity. In fact, Fe isotope fractionation of abiotic iron oxides is often similar to that of biogenic oxides and the specific mineralogical characteristics of magnetite crystals present inside magnetotactic bacteria can be reproduced under abiotic conditions. In summary, the role of bacteria in iron cycling has been the focus of several studies in the last few decades, but clearly, more research is needed in order to fully assess the role of microorganisms in their formation.

Fortin, Danielle; Langley, Sean

2005-09-01

162

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

163

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

164

Effect of cellular iron concentration on iron uptake by hepatocytes.  

PubMed

The effect of intracellular iron content on transferrin and iron uptake by cultured hepatocytes isolated from fetal rat liver was examined with ferric ammonium citrate and the iron chelator desferrioxamine (DFO). Incubation of the cells with ferric ammonium citrate for 24 h significantly increased the cellular nonheme iron level, whereas the number of transferrin binding sites and the uptake of transferrin and iron were reduced. In contrast, when iron-treated cells were incubated with DFO for 24 h, the cellular nonheme iron level was not altered, but the number of transferrin binding sites was increased. Treatment of the cells with exogenous iron and/or DFO did not affect the uptake of transferrin and iron by the nonsaturable processes. These results indicated that, in cultured hepatocytes, transferrin receptor expression and the subsequent uptake of transferrin and iron are regulated by the size of an intracellular, chelatable iron pool, whereas the uptake of iron by the nonsaturable processes is dependent on the extracellular transferrin concentration. PMID:2221071

Trinder, D; Batey, R G; Morgan, E H; Baker, E

1990-10-01

165

Intrahepatic Iron Variation May Greatly Affect the Hepatic Iron Index  

Microsoft Academic Search

The quantitative hepatic iron index is considered the gold standard for the diagnosis of primary hemochromatosis. While intrahepatic variability in the amount of stainable iron in histologic sections of liver is well known, the quantitative variability has not been addressed. Eight native livers removed at transplantation for cirrhosis associated with hepatitis C were studied. Iron-stained sections from multiple different areas

Pedram Argani; Emma E. Furth

1996-01-01

166

Iron sucrose: The oldest iron therapy becomes new  

Microsoft Academic Search

Several parenteral iron preparations are now available. This article focuses on iron sucrose, a hematinic, used more widely than any other for more than five decades, chiefly in Europe and now available in North America. Iron sucrose has an average molecular weight of 34 to 60 kd, and after intravenous (IV) administration, it distributes into a volume equal to that

Jerry Yee; Anatole Besarab

2002-01-01

167

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

168

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

169

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

170

Development and Optimization of Targeted Nanoscale Iron Delivery Methods for Treatment of NAPL Source Zones.  

National Technical Information Service (NTIS)

This project was designed to develop and evaluate innovative nanoscale zero valent iron (nZVI) technologies for application to the treatment of dense nonaqueous phase liquid (DNAPL) source zones. An integrated research program, that combined multi-scale l...

A. Ramsburg K. Pennell L. Abriola

2011-01-01

171

Silver-iron batteries  

NASA Astrophysics Data System (ADS)

Production methods for iron electrodes were studied. It was found that a sintering temperature of 700 C gave the best strength and capacity. Production methods and additions for silver electrodes were also studied. The capacity of the produced iron and silver electrodes were 1100 mAh/cu cm. Different separators were investigated. Cellophane I and II from Du Pont was found to be the best. In tests open cells achieved 60 percent of the calculated capacity. In order to minimize the increase of the pressure in closed cells different additions to the electrodes were studied.

Lindstroem, O.

1980-04-01

172

The Role of Hepcidin in Iron Metabolism  

Microsoft Academic Search

Hepcidin is the central regulator of systemic iron homeostasis. Dysregulation of hepcidin production results in a variety of iron disorders. Hepcidin deficiency is the cause of iron overload in hereditary hemochromatosis, iron-loading anemias, and hepatitis C. Hepcidin excess is associated with anemia of inflammation, chronic kidney disease and iron-refractory iron deficiency anemia. Diagnostic and therapeutic applications of this new knowledge

Elizabeta Nemeth; Tomas Ganz

2009-01-01

173

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

174

Enzymes of respiratory iron oxidation  

SciTech Connect

This report focuses on the progress made in three areas of research concerned with enzymes involved in respiratory iron oxidation. The three areas are as follows: development of an improved procedure for the routine large scale culture of iron oxidizing chemolithotrophs based on the in-situ electrolysis of the soluble iron in the growth medium; to perform iron oxidation kinetic studies on whole cells using the oxygen electrode; and to identify, separate, purify, and characterize the individual cellular components.

Blake, R. II.

1991-01-01

175

An update on iron physiology  

Microsoft Academic Search

Iron is an essential micronutrient, as it is required for adequate erythropoietic function, oxidative metabolism and cellular immune responses. Although the absorption of dietary iron (1-2 mg\\/d) is regulated tightly, it is just balanced with losses. Therefore, internal turnover of iron is essential to meet the requirements for erythropoiesis (20-30 mg\\/d). Increased iron requirements, limited external supply, and increased blood

Manuel Muñoz; Isabel Villar; José Antonio García-Erce; Javier P Gisbert; Fernando Gomollón

176

Iron transport and the kidney  

Microsoft Academic Search

Over the last decade there has been an explosion in our understanding of the proteins that modulate iron homeostasis. Much research has focused on the tissues classically associated with iron absorption and metabolism, namely the duodenum, the liver and the reticulo-endothelial system. Expression profiling has highlighted that many of the components associated with iron homeostasis, are also expressed in tissues

Craig P. Smith; Frank Thévenod

2009-01-01

177

Iron Absorption from Wheat Bread  

Microsoft Academic Search

Bran is known to reduce iron absorption. There is, however, no information on the relationship between the amount of bran added and the decrease in iron absorption. In the present study a comparison was made of the iron absorption from a white wheat bread and a bread baked with different amounts of bran added (from 10 to 0.3%). There was

Erik Björn-Rasmussen

1974-01-01

178

Release of Iron from Hemoglobin.  

National Technical Information Service (NTIS)

The measurement of free iron in hemoglobin solutions as well as the measurement of total hemoglobin-bound iron are important validation assays for large-scale production of hemoglobin-based oxygen carriers. In addition, the detection of iron released from...

S. S. Panter

1993-01-01

179

Iron abundance in galaxy clusters  

Microsoft Academic Search

Up to now, there are 22 clusters of galaxies for which reliable measures of both gas temperature and iron line equivalent width are available. The authors derive the variation of the iron line equivalent width with the temperature. The cluster iron abundance can be deduced from the comparison between the measurements and the computations. Its value appears to be universal,

R. Rothenflug; M. Arnaud

1985-01-01

180

Iron and immunity: immunological consequences of iron deficiency and overload  

PubMed Central

The influence of iron on immune function has been long appreciated. However, the molecular basis for this interaction is less well understood. Recently, there have been several important advances that have shed light on the mechanisms that regulate mammalian iron metabolism. The new insights provide a conceptual framework for understanding and manipulating the cross-talk between iron homeostasis and the immune system. This article will review what is currently known about how disturbances of iron metabolism can affect immunity and how activation of the immune system can lead to alterations in iron balance.

Cherayil, Bobby J.

2011-01-01

181

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

182

Hepatic iron in dialysed patients given intravenous iron dextran.  

PubMed Central

Five percutaneous biopsy and 17 necropsy liver specimens were analysed histologically and chemically for iron content in 22 patients receiving dialysis for chronic renal failure, 13 of whom were given intravenous iron-dextran. Brissot scores for assessing histological hepatic iron deposition and chemically measured liver iron concentrations correlated closely. Both variables depended on total cumulative dose of iron, and to a lesser extent, on time since the last dose. Fibrosis (seen in five patients) was minimal and non-specific. Electron microscopic examination showed that there was no generalised damage and confirmed the presence of iron in the hepatocytes in the form of ferritin. High liver iron concentrations, in excess of 1000 micrograms/100 mg dry weight, were seen in two patients. Four others given comparable cumulated amounts (18-23 g iron) did not have such high concentrations. Plasma ferritin concentrations were high in eight patients, some with and some without fibrosis. The risk of temporarily high iron deposition in the liver causing damage seemed to be minimal when weighed against the benefit of increased haemoglobin in most of the patients. Intravenous iron treatment merits further evaluation, particularly with the advent of erythropoietin treatment, which requires continuously available iron. Images

Fleming, L W; Hopwood, D; Shepherd, A N; Stewart, W K

1990-01-01

183

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

184

Hugoniot data for iron  

Microsoft Academic Search

A definitive set of the Los Alamos Hugoniot data for iron in a pressure regime extending to 442 GPa is given. Earlier standards data, obtained using conventional explosive systems, were thoroughly reprocessed. All original film records were reread. On the basis of more recent experiment and theory, some data were culled because the experimental designs were found to be insufficiently

J. M. Brown; J. N. Fritz; R. S. Hixson

2000-01-01

185

Iron, transferrin and myelinogenesis  

NASA Astrophysics Data System (ADS)

Transferrin (Tf), the iron binding protein of vertebrates serum, is known to be synthesized by oligodendrocytes (Ols) in the central nervous system. It has been postulated that Tf is involved in Ols maturation and myelinogenesis. This link is particularly important in the understanding of a severe human pathology: the multiple sclerosis, which remains without efficient treatment. We generated transgenic mice containing the complete human Tf gene and extensive regulatory sequences from the 5' and 3' untranslated regions that specifically overexpress Tf in Ols. Brain cytoarchitecture of the transgenic mice appears to be normal in all brain regions examined, total myelin content is increased by 30% and motor coordination is significantly improved when compared with non-transgenic littermates. Tf role in the central nervous system may be related to its affinity for metallic cations. Normal and transgenic mice were used for determination of trace metals (iron, copper and zinc) and minerals (potassium and calcium) concentration in cerebellum and corpus callosum. The freeze-dried samples were prepared to allow proton-induced X-ray emission and Rutherford backscattering spectrometry analyses with the nuclear microprobe in Bordeaux. Preliminary results were obtained and carbon distribution was revealed as a very good analysis to distinguish precisely the white matter region. A comparison of metallic and mineral elements contents in brain between normal and transgenic mice shows that iron, copper and zinc levels remained constant. This result provides evidence that effects of Tf overexpression in the brain do not solely relate to iron transport.

Sergeant, C.; Vesvres, M. H.; Devès, G.; Baron, B.; Guillou, F.

2003-09-01

186

Culture's Unacknowledged Iron Grip  

ERIC Educational Resources Information Center

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

Engle, John

2007-01-01

187

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

188

Iron Chelation Therapy  

MedlinePLUS

... the complexity, cost, and technical requirements of this technology have limited its use for measuring iron. Only a handful of SQUID ... called T2 MRI, R2 MRI or quantitative MRI - uses the magnetic properties of ... with biopsy. This technology is relatively new and not all centers have ...

189

Metallurgy Beyond Iron  

Microsoft Academic Search

Metallurgy is one of the oldest sciences. Its history can be traced back to 6000 BCE with the discovery of Gold, and each new discovery - Copper, Silver, Lead, Tin, Iron and Mercury - marked the beginning of a new era of civilization. Currently there are 86 known metals, but until the end of the 17th century, only 12 of

Isabella Gallino; Ralf Busch

2009-01-01

190

The Rusting of Iron  

Microsoft Academic Search

IN NATURE of February 21 (p. 390) appears a letter from Prof. Wyndham R. Dunstan in which he represents me as having concluded ``that carbonic acid is essential to the rusting of iron, and that rusting does not occur in its absence.'' As such a general statement, without reference to the context of the paper to which Prof. Dunstan refers,

Gerald T. Moody

1907-01-01

191

The role of iron regulatory proteins in mammalian iron homeostasis and disease  

Microsoft Academic Search

Iron regulatory proteins 1 and 2 (IRP1 and IRP2) are mammalian proteins that register cytosolic iron concentrations and post-transcriptionally regulate expression of iron metabolism genes to optimize cellular iron availability. In iron-deficient cells, IRPs bind to iron-responsive elements (IREs) found in the mRNAs of ferritin, the transferrin receptor and other iron metabolism transcripts, thereby enhancing iron uptake and decreasing iron

Tracey A Rouault

2006-01-01

192

Failure analysis of a crankshaft made from ductile cast iron  

Microsoft Academic Search

This paper describes the failure analysis of a diesel engine crankshaft used in a truck, which is made from ductile cast iron. The crankshaft was found to break into two pieces at the crankpin portion before completion of warranty period. The crankshaft was induction hardened. An evaluation of the failed crankshaft was undertaken to assess its integrity that included a

Osman Asi

2006-01-01

193

Effect of dietary iron source and iron status on iron bioavailability tests in the rat  

SciTech Connect

Weanling male rats were made anemic in 7 days by feeding a low iron diet and bleeding. Healthy rats were fed the low iron diet supplemented with ferrous sulfate (29 ppm Fe). Each group was subdivided and fed for 10 days on test diets containing about 29 ppm iron that were formulated with meat:spinach mixtures or meat:soy mixtures to provided 100:0, 75:25, 50:50, 25:75, or 0:100% of the dietary iron from these sources or from a ferrous sulfate diet. After 3 days on the diets all rats were dosed orally with 2 or 5 micro curries of /sup 59/Fe after a 18 hour fast and refeeding for 1.5 hours. Iron status influenced liver iron, carcass iron, liver radio activity and percent of radioactive dose retained. Diet influenced fecal iron and apparent absorption of iron. In iron bioavailability studies assessment methodology and iron status of the test subject greatly influences the estimates of the value of dietary sources of iron.

Zhang, D.; Hendricks, D.G.; Mahoney, A.W.

1986-03-05

194

Iron Aluminide Composites  

SciTech Connect

Iron aluminides with the B2 structure are highly oxidation and corrosion resistant. They are thermodynamically compatible with a wide range of ceramics such as TiC, WC, TiB{sub 2}, and ZrB{sub 2}. In addition, liquid iron aluminides wet these ceramics very well. Therefore, FeAl/ceramic composites may be produced by techniques such as liquid phase sintering of powder mixtures, or pressureless melt infiltration of ceramic powders with liquid FeAl. These techniques, the resulting microstructure, and their advantages as well as limitations are described. Iron aluminide composites can be very strong. Room temperature flexure strengths as high as 1.8 GPa have been observed for FeAl/WC. Substantial gains in strength at elevated temperatures (1073 K) have also been demonstrated. Above 40 vol.% WC the room temperature flexure strength becomes flaw-limited. This is thought to be due to processing flaws and limited interfacial strength. The fracture toughness of FeAl/WC is unexpectedly high and follows a mile of mixtures. Interestingly, sufficiently thin (< 1 {micro}m) FeAl ligaments between adjacent WC particles fracture not by cleavage, but in a ductile manner. For these thin ligaments the dislocation pile-ups formed during deformation are not long enough to nucleate cleavage fracture, and their fracture mode is therefore ductile. For several reasons, this brittle-to-ductile size transition does not improve the fracture toughness of the composites significantly. However, since no cleavage cracks are nucleated in sufficiently thin FeAl ligaments, slow crack growth due to ambient water vapor does not occur. Therefore, as compared to monolithic iron aluminizes, environmental embrittlement is dramatically reduced in iron aluminide composites.

Schneibel, J.H.

1998-11-20

195

Ferrioxamine excretion in iron-loaded man  

SciTech Connect

Factors affecting iron excretion after subcutaneous desferrioxamine infusion were evaluated in individuals with iron overload. Urinary iron varied directly, whereas stool iron varied inversely with the level of erythropoiesis. Ascorbic acid greatly enhanced urinary iron excretion but had a less constant effect on stool iron. Stool iron losses contributed a greater proportion of total iron excretion at higher chelator dosage. These studies indicate the importance of biliary iron excretion in monitoring the effectiveness of desferrioxamine. They also suggest that large chelator doses may remove established iron overload much more rapidly than has previously been realized.

Pippard, M.J. (Univ. of Washington, Seattle); Callender, S.T.; Finch, C.A.

1982-08-01

196

[Iron and invasive fungal infection.  

PubMed

Iron is an essential factor for both the growth and virulence of most of microorganisms. As a part of the innate (or nutritional) immune system, mammals have developed different mechanisms to store and transport this element in order to limit free iron bioavailability. To survive in this hostile environment, pathogenic fungi have specific uptake systems for host iron sources, one of the most important of which is based on the synthesis of siderophores-soluble, low-molecular-mass, high-affinity iron chelators. The increase in free iron that results from iron-overload conditions is a well-established risk factor for invasive fungal infection (IFI) such as mucormycosis or aspergillosis. Therefore, iron chelation may be an appealing therapeutic option for these infections. Nevertheless, deferoxamine -the first approved iron chelator- paradoxically increases the incidence of IFI, as it serves as a xeno-siderophore to Mucorales. On the contrary, the new oral iron chelators (deferiprone and deferasirox) have shown to exert a deleterious effect on fungal growth both in vitro and in animal models. The present review focuses on the role of iron metabolism in the pathogenesis of IFI and summarises the preclinical data, as well as the limited clinical experience so far, in the use of new iron chelators as treatment for mucormycosis and invasive aspergillosis. PMID:23684655

Alvarez, Florencio; Fernández-Ruiz, Mario; Aguado, José María

2013-05-14

197

Iron dysregulation in movement disorders.  

PubMed

Iron is an essential element necessary for energy production, DNA and neurotransmitter synthesis, myelination and phospholipid metabolism. Neurodegeneration with brain iron accumulation (NBIA) involves several genetic disorders, two of which, aceruloplasminemia and neuroferritinopathy, are caused by mutations in genes directly involved in iron metabolic pathway, and others, such as pantothenate-kinase 2, phospholipase-A2 and fatty acid 2-hydroxylase associated neurodegeneration, are caused by mutations in genes coding for proteins involved in phospholipid metabolism. Phospholipids are major constituents of myelin and iron accumulation has been linked to myelin derangements. Another group of NBIAs is caused by mutations in lysosomal enzymes or transporters such as ATP13A2, mucolipin-1 and possibly also ?-galactosidase and ?-fucosidase. Increased cellular iron uptake in these diseases may be caused by impaired recycling of iron which normally involves lysosomes. Abnormal iron utilization by mitochondria, as has been proposed in Friedreich's ataxia, is another possible mechanism of iron accumulation. Other, more common degenerative movement disorders, such as Parkinson's disease, Huntington's disease, multiple system atrophy and progressive supranuclear palsy also exhibit increased brain iron content. Finally, brain iron deficiency has been implicated in restless legs syndrome. This review provides an update on recent findings related to genetics, pathogenic mechanisms, diagnosis, and treatment of movement disorders associated with dysregulation of brain iron. We also propose a new classification of NBIAs. PMID:22266337

Dusek, Petr; Jankovic, Joseph; Le, Weidong

2012-01-12

198

Identification of Discrete Domains within Gonococcal Transferrin-Binding Protein A That Are Necessary for Ligand Binding and Iron Uptake Functions  

Microsoft Academic Search

The availability of free iron in vivo is strictly limited, in part by the iron-binding protein transferrin. The pathogenic Neisseria spp. can sequester iron from this protein, dependent upon two iron-repressible, trans- ferrin-binding proteins (TbpA and TbpB). TbpA is a TonB-dependent, integral, outer membrane protein that may form a b-barrel exposing multiple surface loops, some of which are likely to

IAN C. BOULTON; MARY KATE YOST; JAMES E. ANDERSON; CYNTHIA NAU CORNELISSEN

2000-01-01

199

Importance of iron chelation in free radical-induced oxidative stress and human disease.  

PubMed

Iron is a redox active metal involved in the oxidation-reduction reactions and regulation of cell growth and differentiation. Iron is an integral part of many proteins and enzymes that maintains various physiological functions. Most of the human body's iron is contained in red blood cells. Despite iron being an abundant trace metal in food, millions of people worldwide suffer from anemia. Iron deficiency results in impaired production of iron-containing proteins and inhibition of cell growth. In contrast, abnormal iron uptake has been related to the most common hereditary disease hemochromatosis, leading to tissue damage derived from free radical toxicity. In addition, disruption of iron regulation plays a key role in the etiology of Alzheimer's disease, Parkinson's disease, Huntington's disease, Friedreich's ataxia and other neurological disorders, cancer (lung cancer, breast cancer, colon cancer), Fanconi anemia, stroke and ageing. Thus the control of this necessary but potentially toxic substance is an important part of many aspects of human health and disease. The most frequent is the toxic role of iron linked with the catalytic decomposition of hydrogen peroxide (Fenton reaction) leading to the formation of reactive oxygen species (ROS) causing damage to biomolecules, including lipids, proteins and DNA. The binding of iron-designed chelators via nitrogen, oxygen or sulphur donor atoms blocks iron s ability to catalyze the formation of free radicals. Thus the design of various metal chelators to prevent free radical reactions is an important approach in the treatment of many iron-related diseases. The development of effective dual functioning antioxidants, possessing both metal-chelating and free radical-scavenging properties is awaited. The aim of this review is to discuss the role of iron and importance of iron-chelation in human disease and ageing. PMID:21902663

Jomova, Klaudia; Valko, Marian

2011-01-01

200

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

Code of Federal Regulations, 2010 CFR

...Distribution lines other than cast iron or ductile iron lines. 192.487 Section 192...Distribution lines other than cast iron or ductile iron lines. (a) General corrosion. Except for cast iron or ductile iron pipe, each segment...

2009-10-01

201

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

Code of Federal Regulations, 2010 CFR

...Distribution lines other than cast iron or ductile iron lines. 192.487 Section 192...Distribution lines other than cast iron or ductile iron lines. (a) General corrosion. Except for cast iron or ductile iron pipe, each segment...

2010-10-01

202

Feo – Transport of Ferrous Iron into Bacteria  

Microsoft Academic Search

Summary  Bacteria commonly utilise a unique type of transporter, called Feo, to specifically acquire the ferrous (Fe2+) form of iron from their environment. Enterobacterial Feo systems are composed of three proteins: FeoA, a small, soluble\\u000a SH3-domain protein probably located in the cytosol; FeoB, a large protein with a cytosolic N-terminal G-protein domain and\\u000a a C-terminal integral inner-membrane domain containing two ‘Gate’

Michaël L. Cartron; Sarah Maddocks; Paul Gillingham; C. Jeremy Craven; Simon C. Andrews

2006-01-01

203

Iron Resources and Ocanic Nutrients: Advancement of Global Environment Simulations  

NASA Astrophysics Data System (ADS)

Iron limits phytoplankton growth in more than 40 percent of the oceans and is a co-limitation in the remaining 60 percent of surface waters. Moreover the paradigm of a single limiting factor for plankton blooms has given way to the concept of co-limitation by light, and the nutrient elements N, Fe, P and Si. Primary production, export into the deep sea, and CO2 uptake from the atmosphere together form the biological pump in Ocean Biogeochemical Climate Models (OBCM's). The IRONAGES project is a consortium of 12 European institutes developing more realistic OBCM's for budgeting and exchanges of both CO2 and DMS, by implementing the following improvements: (i) co-limitation by four nutrients N, Fe, P, Si simultaneously; (ii) five major bloom-forming taxonomic groups, the diatoms, calcifiers, N2-fixers, Phaecystis sp. and nano-pico-plankton; (iii) DMS(P) pathways; (iv) integrated plankton ecosystem modeling; (v) realistic global oceanic iron cycling, on basis of: (vi) iron supply from below reducing sediments; (vii) iron supply from above aeolian dust input; (viii) several chemical forms of iron in surface waters; (ix) certification of iron data in the oceans.

de Baar, H.; Ironages Team

2003-04-01

204

MRI of Brain Iron  

Microsoft Academic Search

A prominently decreased signal intensity in the globus pallidum, reticular substantia nigra, red nucleus, and dentate nucleus was routinely noted in 150 consecutive individ- uals on T2-weighted images (SE 2000\\/100) using a high field strength (1.5 T) MR system. This MR finding correlated closely with the decreased estimated T2 relaxation times and the sites of preferential accumulation of ferric iron

Burton Drayer; Peter Burgers; Robert Darwin; Stephen Riederer; Robert Herfkens; G. Allan Johnson

1986-01-01

205

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

206

Iron Currency-Bars  

Microsoft Academic Search

IN NATURE of May 19, p. 372, reference is made to iron currency-bars and ``early British water-clocks.'' The discovery of the true nature of the currency-bars is not, as is implied, a recent one, but was made in 1905 by Mr. Reginald Smith (see his paper, Proceedings of the Society of Antiquaries, vol. xx., pp. 179-94). Similarly, the ``early British

O. G. S. Crawford

1921-01-01

207

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

208

Iron and Immunity: Immunological Consequences of Iron Deficiency and Overload  

Microsoft Academic Search

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

Bobby J. Cherayil

2010-01-01

209

Iron Transport in Mycobacterium smegmatis: Uptake of Iron from Ferriexochelin  

Microsoft Academic Search

Exochelins are a group of extracellular iron chelators produced by mycobacteria. Iron uptake by washed suspensions of iron-deficiently grown Mycobacterium smegmatis from 55Fe(III)-exochelin fractions (at about 1 ,UM) was greatest from the fractions containing the compounds that naturally predominate in culture filtrates. Uptake from the major fraction, as well as from combined exochelins, had a K, of about 6,u~ and

MARIS C. STEPHENSON; COLIN RATLEDGE

1979-01-01

210

Iron speciation in iron-rich wood by Mössbauer spectroscopy  

Microsoft Academic Search

Several iron-rich wood samples were investigated using Mössbauer spectroscopy to obtain information on the chemical state\\u000a of the iron species contained in them. The Mössbauer spectrum of Japanese cedar (Cryptomeria japonica D. Don) wood containing iron species that originated from rusted nails exhibited a symmetrical doublet from a high-spin Fe(III)\\u000a species, which is expected to be ?-FeOOH (lepidocrocite). Mössbauer absorption

Shigeru Yamauchi; Yoichi Sakai; Hikaru Aimi

211

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

212

Iron homeostasis: new players, newer insights.  

PubMed

Although iron is a relatively abundant element in the universe, it is estimated that more than 2 billion people worldwide suffer from iron deficiency anemia. Iron deficiency results in impaired production of iron-containing proteins, the most prominent of which is hemoglobin. Cellular iron deficiency inhibits cell growth and subsequently leads to cell death. Hemochromatosis, an inherited disorder results in disproportionate absorption of iron and the extra iron builds up in tissues resulting in organ damage. As both iron deficiency and iron overload have adverse effects, cellular and systemic iron homeostasis is critically important. Recent advances in the field of iron metabolism have led to newer understanding of the pathways involved in iron homeostasis and the diseases which arise from alteration in the regulators. Although insight into this complex regulation of the proteins involved in iron homeostasis has been obtained mainly through animal studies, it is most likely that this knowledge can be directly extrapolated to humans. PMID:18754855

Edison, Eunice S; Bajel, Ashish; Chandy, Mammen

2008-09-13

213

Serum Iron and Iron-Binding Capacity in Normal Subjects  

PubMed Central

Normal values for serum iron and unsaturated iron-binding capacity of serum were established in a carefully selected group of control subjects by a modification of the procedure described by Schade and coworkers. No significant difference was found between mean values in males and females, and there was no correlation between serum iron levels and age in adults. The value of serum iron as a diagnostic aid is limited by the wide range in normal subjects and the large variation that occurs in the same individual from hour to hour and day to day.

Card, Robert T.; Brown, G. Malcolm; Valberg, Leslie S.

1964-01-01

214

Iron metabolism, iron deficiency, thrombocytosis, and the cardiorenal anemia syndrome.  

PubMed

In treating moderate to severe anemia of chronic kidney disease (CKD), oral iron is effective only in a minority of nondialysis patients. Intravenous iron is more effective and can raise levels of hemoglobin even without the use of erythropoiesis-stimulating agents (ESAs). Unfortunately, the current assays of iron status that are presently 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 <100 ng/ml to 800 ng/ml. None of the three available randomized controlled trials comparing oral with i.v. iron showed evidence of nephrotoxicity caused by i.v. iron. Iron deficiency is a risk factor for thrombocytosis and should, wherever possible, be avoided. Optimal coadministration of iron may reduce the risk for ESA-driven cardiovascular events. Increased total body iron stores (imperfectly reflected by serum ferritin levels in CKD) do not appear to be related to such events or hospitalization in CKD; it is unclear what other risk factors and mechanisms need to be considered. In the appreciable proportion of patients with both renal and cardiac dysfunction, management is further complicated by a vicious circle (which can be characterized as cardiorenal anemia syndrome) in which CKD, heart failure, and anemia exacerbate each other. In such patients, correction of anemia appears to improve cardiac function and quality of life without a greater risk for adverse events. PMID:19762514

Besarab, Anatole; Hörl, Walter Hermann; Silverberg, Donald

2009-01-01

215

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

216

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

217

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

218

An international registry for neurodegeneration with brain iron accumulation.  

PubMed

We report the development of an international registry for Neurodegeneration with Brain Iron Accumulation (NBIA), in the context of TIRCON (Treat Iron-Related Childhood-Onset Neurodegeneration), an EU-FP7 - funded project. This registry aims to combine scattered resources, integrate clinical and scientific knowledge, and generate a rich source for future research studies. This paper describes the content, architecture and future utility of the registry with the intent to capture as many NBIA patients as possible and to offer comprehensive information to the international scientific community. PMID:22985983

Kalman, Bernadette; Lautenschlaeger, Ronald; Kohlmayer, Florian; Büchner, Boriana; Kmiec, Thomas; Klopstock, Thomas; Kuhn, Klaus A

2012-09-17

219

Snapshot of iron response in Shewanella oneidensis by gene network reconstruction  

PubMed Central

Background Iron homeostasis of Shewanella oneidensis, a ?-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. Conclusion 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

2009-01-01

220

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

221

Iron metabolism in mammalian cells.  

PubMed

Most living things require iron to exist. Iron has many functions within cells but is rarely found unbound because of its propensity to catalyze the formation of toxic free radicals. Thus the regulation of iron requirements by cells and the acquisition and uptake of iron into tissues in multicellular organisms is tightly regulated. In humans, understanding iron transport and utility has recently been advanced by a "great conjunction" of molecular genetics in simple organisms, identifying genes involved in genetic diseases of metal metabolism and by the application of traditional cell physiology approaches. We are now able to approach a rudimentary understanding of the "iron cycle" within mammals. In the future, this information will be applied toward modulating the outcome of therapies designed to overcome diseases involving metals. PMID:11597005

Walker, B L; Tiong, J W; Jefferies, W A

2001-01-01

222

Integrated Neighborhood and Integrated Education  

ERIC Educational Resources Information Center

|The author is executive director of National Neighbors, a nationwide federation of interracial neighborhoods working to strengthen and encourage successful integrated communities, and to keep integrated schools integrated so that integrated neighborhoods can stay that way. (Author/JM)|

Milgram, Jean Gregg

1974-01-01

223

Magnetostructural study of iron sucrose  

Microsoft Academic Search

Magnetic and structural analyses have been performed on an iron sucrose complex used as a haematinic agent. The system contains two-line ferrihydrite particles of about 5nm that are superparamagnetic above approximately 50K. The observed low-temperature magnetic dynamics of this compound is closer to simple models than in the case of other iron-containing drugs for intravenous use like iron dextran.

Lucía Gutiérrez; María del Puerto Morales; Francisco José Lázaro

2005-01-01

224

Magnetostructural study of iron sucrose  

NASA Astrophysics Data System (ADS)

Magnetic and structural analyses have been performed on an iron sucrose complex used as a haematinic agent. The system contains two-line ferrihydrite particles of about 5 nm that are superparamagnetic above approximately 50 K. The observed low-temperature magnetic dynamics of this compound is closer to simple models than in the case of other iron-containing drugs for intravenous use like iron dextran.

Gutiérrez, Lucía; del Puerto Morales, María; José Lázaro, Francisco

2005-05-01

225

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

226

Enzymes of respiratory iron oxidation  

Microsoft Academic Search

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

Blake; R. II

1992-01-01

227

Labile iron in parenteral iron formulations: a quantitative and comparative study  

Microsoft Academic Search

Background. Evidence of iron-mediated oxidative stress, neutrophil dysfunction and enhanced bacterial growth after intravenous (IV) iron administration has been ascribed to a labile or bioactive iron fraction present in all IV iron agents. Methods. To quantify and compare the size of the labile fraction in several classes of IV iron agents, we examined iron donation to transferrin (Tf) in vitro

David Van Wyck; Jaime Anderson; Kevin Johnson

228

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

Code of Federal Regulations, 2010 CFR

...iron and malleable iron. (a) The low ductility of cast iron and malleable iron should be recognized and the use of these metals where shock loading may occur should be avoided. Cast iron and malleable iron components shall not be used at...

2010-10-01

229

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

Code of Federal Regulations, 2010 CFR

...iron and malleable iron. (a) The low ductility of cast iron and malleable iron should be recognized and the use of these metals where shock loading may occur should be avoided. Cast iron and malleable iron components shall not be used at...

2009-10-01

230

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

231

Calcium, iron and neuronal function.  

PubMed

Calcium and iron play dual roles in neuronal function: they are both essential but when present in excess they cause neuronal damage and may even induce neuronal death. Calcium signals are required for synaptic plasticity, a neuronal process that entails gene expression and which is presumably the cellular counterpart of cognitive brain functions such as learning and memory. Neuronal activity generates cytoplasmic and nuclear calcium signals that in turn stimulate pathways that promote the transcription of genes known to participate in synaptic plasticity. In addition, evidence discussed in this article shows that iron deficiency causes learning and memory impairments that persist following iron repletion, indicating that iron is necessary for normal development of cognitive functions. Recent results from our group indicate that iron is required for long-term potentiation in hippocampal CA1 neurons and that iron stimulates ryanodine receptor-mediated calcium release through ROS produced via the Fenton reaction leading to stimulation of the ERK signaling pathway. These combined results support a coordinated action between iron and calcium in synaptic plasticity and raise the possibility that elevated iron levels may contribute to neuronal degeneration through excessive intracellular calcium increase caused by iron-induced oxidative stress. PMID:17505966

Hidalgo, Cecilia; Núñez, Marco T

232

Biogeochemical impact of a model western iron source in the Pacific Equatorial Undercurrent  

NASA Astrophysics Data System (ADS)

Trace element distributions in the source waters of the Pacific Equatorial Undercurrent (EUC) show the existence of elevated total acid-soluble iron concentrations. This region has been suggested to contribute enough bioavailable iron to regulate interannual and interglacial variability in biological productivity downstream in the high-nitrate low-chlorophyll upwelling zone of the eastern equatorial Pacific. We investigated the advection and first-order biogeochemical impact of an imposed, data-based iron maximum in the western Pacific EUC using an ecosystem model forced by a global dynamical model. We imposed two source profiles of iron constrained by total acid-soluble iron measurements. Though the data for total acid-soluble iron included both dissolved and acid-soluble particulate iron species, we treated all of the total acid-soluble iron as if it was dissolved and bioavailable. A deeper (270 m) source was centered in the density horizon of the observed iron maximum and a shallower (180 m) source was located in the core of our model's EUC, where a dissolved iron maximum has been frequently postulated. These source runs were compared with a control run that contained no specific source of iron associated with the EUC. In the source runs elevated iron concentrations were simulated in the EUC across its entire zonal span, evident as a subsurface plume of dissolved iron slightly below the core of the EUC. In the control run there was no iron maximum associated with the EUC. Upwelling of iron-replete water in the central and eastern equatorial Pacific increased integrated primary productivity in the Wyrtki box (180°W:90°W, 5°S:5°N, 0:200 m) by 41% and 66% for the deeper and shallower iron perturbation, respectively. The source runs increased the realism of the zonal extent of HNLC conditions and the meridional distributions of biological productivity, relative to the control run. However, in the source simulations surface chlorophyll concentrations were too high by a factor of two and maximum surface nitrate concentrations were too low, relative to climatologies. The relative abundance of diatoms roughly doubled upon the input of additional iron, exceeding field observations. Though biogeochemical data are limited and we did not adjust parameters to optimize the model fits to observations, these results suggest that acid-soluble particulate iron supplied to the EUC in the western equatorial Pacific is unlikely to be entirely bioavailable.

Slemons, Lia; Gorgues, Thomas; Aumont, Olivier; Menkes, Christophe; Murray, James W.

2009-12-01

233

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

SciTech Connect

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

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

1997-11-01

234

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

PubMed

Aerobes and anaerobes alike express a plethora of essential iron enzymes; in the resting state, the iron atom(s) in these proteins are in the ferrous state. For aerobes, ferric iron is the predominant environmental valence form which, given ferric iron's aqueous chemistry, occurs as 'rust', insoluble, bio-inert polymeric ferric oxide that results from the hydrolysis of [Fe(H(2)O)(6)](3+). Mobilizing this iron requires bio-ferrireduction which in turn requires managing the rapid autoxidation of the resulting Fe(II) which occurs at pH > 6. This review examines the aqueous redox chemistry of iron and the mechanisms evolved in aerobes to suppress the 'rusting out' of Fe(III) and the ROS-generating autoxidation of Fe(II) so as to make this metal ion available as the most ubiquitous prosthetic group in metallobiology. PMID:23264695

Kosman, Daniel J

2013-01-01

235

Prospects for the 2020 Iron Ore Market.Quantitative Analysis of Market Dynamics and Risk Mitigation Strategies  

Microsoft Academic Search

As the key ingredient for steelmaking, iron ore is integral to the global economy and represents the world's second-largest natural resource market by value. The overall structure and dynamics of the iron ore market have recently undergone various radical changes. The global demand shock caused by the rapid industrialization of China has sent market prices skywards and triggered a collapse

Marc P. Bielitza

236

21 CFR 522.1182 - Iron injection.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 2009-04-01 false Iron injection. 522.1182 Section 522...FORM NEW ANIMAL DRUGS § 522.1182 Iron injection. (a) Specifications ...1) 100 milligrams (mg) of elemental iron derived from: (i) Ferric...

2009-04-01

237

21 CFR 73.3125 - Iron oxides.  

Code of Federal Regulations, 2013 CFR

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

2013-04-01

238

Interrelationship of Cobalt and Iron Absorption.  

National Technical Information Service (NTIS)

Cobalt and iron seem to share a common intestinal absorptive pathway. Cobalt decreases iron absorption as effectively as equimolar amounts of carrier iron. Factors which influence the absorption of one metal significantly affect the absorption of the othe...

S. G. Schade B. F. Felsher G. M. Bernier M. E. Conrad

1969-01-01

239

Iron Produced from Recycled Municipal Ferrous Waste.  

National Technical Information Service (NTIS)

Production of gray iron from magnetically separated municipal ferrous waste was investigated. Pig iron formed from the ferrous waste was melted in a local foundry together with regular charge materials to make gray iron. Tensile fracture tests of the cast...

M. A. Imam C. M. Gilmore E. A. H. Purcell

1981-01-01

240

Evidence that stainable bone marrow iron following parenteral iron therapy does not correlate with serum iron studies and may not represent readily available storage iron.  

PubMed

We recently reported that parenteral iron therapy is associated with a characteristic pattern of iron staining on bone marrow aspirate smears. We now present clinical information from 6 patients who received parenteral iron and, at one or more points in follow-up, were found to have low or borderline low serum ferritin levels and/or serum iron levels, even though marrow aspirate smears revealed abundant stainable iron in the pattern characteristic of prior parenteral iron therapy. We conclude that stainable iron seen in this pattern does not correlate with serum iron studies and may not represent functionally available storage iron. This pattern of iron staining should not be used as evidence to withhold further iron therapy in patients who otherwise continue to have features of iron deficiency anemia. PMID:19289594

Thomason, Ronald W; Almiski, Muhamad S

2009-04-01

241

Studies of Alternating Current Corrosion of Iron.  

National Technical Information Service (NTIS)

An analysis of the effects of alternating current on the corrosion of iron is presented. The corrosion efficiency of iron, generation efficiency of hydrogen gas, and polarization characteristics in the alternating current electrolysis of iron in the aqueo...

Y. Torigoe

1972-01-01

242

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

243

Iron Metabolism and Iron Chelation in Sickle Cell Disease  

Microsoft Academic Search

This review highlights recent advances in iron metabolism that are relevant to sickle cell disease (SCD). SCD is a common hemoglobinopathy that results in chronic inflammation. Improved understanding of how iron metabolism is controlled by proteins such as hepcidin, ferroportin, hypoxia-inducible factor 1, and growth differentiation factor 15 have revealed how they are involved in the organ toxicity of SCD.

Patrick B. Walter; Paul Harmatz; Elliott Vichinsky

2009-01-01

244

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

245

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

246

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

247

Iron regulatory proteins in pathobiology.  

PubMed

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. PMID:11085915

Cairo, G; Pietrangelo, A

2000-12-01

248

Fluidized bed for removing iron and acidity from acid mine drainage  

SciTech Connect

Acid mine drainage (AMD) continues to be an important water pollution problem around the world. A fluidized bed reactor (FBR) for the removal of iron from acid mine drainage (AMD) was evaluated as part of a prototype multistage system, which included a bioreactor to oxidize ferrous iron, an FBR for the precipitation of ferric iron as a coating on media, and a carbonate bed (CB) for pH control. In the integrated system, a 99% iron removal efficiency was achieved, with effluent iron concentration remaining <3 mg L{sup {minus}1} and pH > 6. The optimum pH for iron removal in the FBR was about pH 3.5. Above that pH, and above an iron loading of about 0.20 mg Fe h{sup {minus}1} m{sup {minus}2} reactor surface area, suspended iron particles developed in the reactor system. Particulates in the feed had an adverse impact on the removal performance of the system. Schwertmannite appeared to be the predominant mineral formed in the precipitation reactor. Coating growth on the sand media appeared to result from the attachment and consolidation of small iron particles (<1.0 {mu}m) that formed in the bulk solution.

Diz, H.R.; Novak, J.T. [Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States). Dept. of Civil Engineering

1998-08-01

249

Iron salts dosage for sulfide control in sewers induces chemical phosphorus removal during wastewater treatment.  

PubMed

Chemical phosphorus (P) removal during aerobic wastewater treatment induced by iron salt addition in sewer systems for sulfide control is investigated. Aerobic batch tests with activated sludge fed with wastewater containing iron sulfide precipitates showed that iron sulfide was rapidly reoxidised in aerobic conditions, resulting in phosphate precipitation. The amount of P removed was proportional to the amount of iron salts added, and for the sludge used, ratios of 0.44 and 0.37 mgP/mgFe were obtained for ferric and ferrous dosages, respectively. The hydraulic retention time (HRT) of iron sulfide in sewers was found to have a crucial impact on the settling of iron sulfide precipitates during primary settling, with a shorter HRT resulting in a higher concentration of iron sulfide in the primary effluent and thus enabling higher P removal. A mathematical model was developed to describe iron sulfide oxidation in aerated activated sludge and the subsequent iron phosphate precipitation. The model was used to optimise FeCl(3) dosing in a real wastewater collection and treatment system. Simulation studies revealed that, by moving FeCl(3) dosing from the WWTP, which is the current practice, to a sewer location upstream of the plant, both sulfide control and phosphate removal could be achieved with the current ferric salt consumption. This work highlights the importance of integrated management of sewer networks and wastewater treatment plants. PMID:20434190

Gutierrez, Oriol; Park, Donghee; Sharma, Keshab R; Yuan, Zhiguo

2010-04-09

250

The Iron Within  

NSDL National Science Digital Library

Forty-fifth monthly installment of our "What A Year!" website project, introducing life science breakthroughs to middle and high school students and their teachers. In order to cause infection, pathogenic bacteria must be able to obtain all the nutrients they need from the human body, including metals such as zinc, iron, and manganese. As a result, many vertebrate species (including humans) have evolved ways to store these metals in forms that are not readily accessible to bacteria. This mechanism is known as nutritional immunity. Staphylococcus aureus has developed such a mechanism, making it a very successful invader.

2011-02-01

251

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

252

Studies of hypervalent iron.  

PubMed

The iron(IV), (V) and (VI) oxidation states are of great interest because of their role in catalytic oxidation/hydroxylation reactions. This report summarizes the information currently available on the kinetic and chemical properties of the water-soluble ions of FeO4(2-), FeO4(3-), and FeO4(4-), their protonated forms and/or simple complex derivatives. The discussion includes their radiation-induced formation, decay kinetics, reactivity with other compounds, determination of their respective pKa values as well as spectral properties. PMID:2060824

Bielski, B H

1991-01-01

253

The Iron line (stacked) emission properties of Chandra surveys sources  

NASA Astrophysics Data System (ADS)

We exploit deep Chandra data in the CDF-S (4Ms), CDF-N (2Ms), E-CDF-S (250 ks) COSMOS (160 ks) and AEGIS (800 ks) fields to perform source stacking analyses of iron K lines in integrated X-ray spectra of the ~190 brightest X-ray sources, as a function of luminosity, redshift, and absorption column density. The combined Chandra datasets substantially improve the statistics for the low-redshift AGN population (z<1) and provide new sources detected mostly at z>1. The average rest-frame properties of AGN can be studied, allowing a full characterization of the line intensity and line profile. The available multi-wavelength data allow us to study Iron-line properties also as a function of the optical properties of the AGN host galaxies (stellar masses, star formation rates), therefore putting the production of iron within the more general AGN-host galaxies co-evolution framework.

Brusa, Marcella; Mainieri, V.; Santini, P.; Rosario, D.

2012-09-01

254

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

Microsoft Academic Search

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

Balvant Rajani; Jon Makar

2000-01-01

255

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

256

Integrating Art.  

ERIC Educational Resources Information Center

|These articles focus on art as a component of interdisciplinary integration. (1) "Integrated Curriculum and the Visual Arts" (Anna Kindler) considers various aspects of integration and implications for art education. (2) "Integration: The New Literacy" (Tim Varro) illustrates how the use of technology can facilitate cross-curricular integration.…

BCATA Journal for Art Teachers, 1991

1991-01-01

257

Integrating Art.  

ERIC Educational Resources Information Center

These articles focus on art as a component of interdisciplinary integration. (1) "Integrated Curriculum and the Visual Arts" (Anna Kindler) considers various aspects of integration and implications for art education. (2) "Integration: The New Literacy" (Tim Varro) illustrates how the use of technology can facilitate cross-curricular integration.…

BCATA Journal for Art Teachers, 1991

1991-01-01

258

Serum hepcidin levels in Helicobacter pylori-infected children with iron-deficiency anemia: a case-control study.  

PubMed

Recently, hepcidin, an antimicrobial-like peptide hormone, has evolved as the master regulator of systemic iron homeostasis. Hepcidin integrates signals from diverse physiological inputs, forming a key connection between iron trafficking and response to infection. In this study, we aimed to investigate whether Helicobacter pylori infection modulates serum hepcidin level and response to oral iron therapy in children with iron-deficiency anemia. This was a case-control study including 60 children with iron-deficiency anemia (IDA; 30 H. pylori infected and 30 H. pylori noninfected) and 30 healthy children with comparable age and gender as the control group. Iron parameters including serum iron, ferritin, transferrin, total iron binding capacity, and transferrin saturation and serum hepcidin levels were assessed initially and after 3 months of oral iron therapy for IDA. Compared to the control group, serum hepcidin was significantly lower in H. pylori-noninfected children with IDA (P?iron therapy (P?iron therapy (P?>?0.05). Although hepcidin showed significant positive correlations with serum ferritin, hemoglobin (Hb), iron, and transferrin saturation in noninfected children with IDA (P?iron, and transferrin saturation in H. pylori-infected children with IDA (P?iron therapy in children with iron-deficiency anemia. PMID:23760782

Azab, Seham F A; Esh, Asmaa M H

2013-06-13

259

Fetal and neonatal iron deficiency causes volume loss and alters the neurochemical profile of the adult rat hippocampus  

PubMed Central

Objective Perinatal iron deficiency results in persistent hippocampus-based cognitive deficits in adulthood despite iron supplementation. The objective of the present study was to determine the long-term effects of perinatal iron deficiency and its treatment on hippocampal anatomy and neurochemistry in formerly iron-deficient young adult rats. Methods Perinatal iron deficiency was induced using a low-iron diet during gestation and the first postnatal week in male rats. Hippocampal size was determined using volumetric magnetic resonance imaging at 8 weeks of age. Hippocampal neurochemical profile, consisting of 17 metabolites indexing neuronal and glial integrity, energy reserves, amino acids, and myelination, was quantified using high-field in vivo 1H NMR spectroscopy at 9.4 T (N = 11) and compared with iron-sufficient control group (N = 10). Results The brain iron concentration was 56% lower than the control group at 7 days of age in the iron-deficient group, but had recovered completely at 8 weeks. The cross-sectional area of the hippocampus was decreased by 12% in the formerly iron-deficient group (P = 0.0002). The hippocampal neurochemical profile was altered: relative to the control group, creatine, lactate, N-acetylaspartylglutamate, and taurine concentrations were 6–29% lower, and glutamine concentration 18% higher in the formerly iron-deficient hippocampus (P < 0.05). Discussion Perinatal iron deficiency was associated with reduced hippocampal size and altered neurochemistry in adulthood, despite correction of brain iron deficiency. The neurochemical changes suggest suppressed energy metabolism, neuronal activity, and plasticity in the formerly iron-deficient hippocampus. These anatomic and neurochemical changes are consistent with previous structural and behavioral studies demonstrating long-term hippocampal dysfunction following perinatal iron deficiency.

Rao, Raghavendra; Tkac, Ivan; Schmidt, Adam T.; Georgieff, Michael K.

2011-01-01

260

Widmanstatten ferrite in lunar iron  

Microsoft Academic Search

Fragments of lunar matter recovered by Luna 16 are subjected to metallographic analyses. Based on thermodynamic analyses, the specific nature of the Widmanstatten ferrite found in the high-iron lunar metal is discussed. The Widmanstatten microstructure of the iron-nickel lunar metal differs morphologically from the Widmanstatten structure found in meteorities. Chemical data indicate similar processes are responsible for the development of

R. I. Mints; T. M. Petukhova; V. M. Segal; L. S. Tarasov

1975-01-01

261

Widmanstatten ferrite in lunar iron  

Microsoft Academic Search

Fragments of lunar matter recovered by Luna 16 are subjected to metallographic analyses. Based on thermodynamic analyses, the specific nature of the Widmanstatten ferrite found in the high-iron lunar metal is discussed. The Widmanstatten microstructure of the iron-nickel lunar metal differs morphologically from the Widmanstatten structure found in meteorities. Chemical data indicate similar processes are responsible for the development of

R. I. Mints; T. M. Petukhova; V. M. Segal; L. S. Tarasov

1974-01-01

262

Neurodegeneration with brain iron accumulation  

Microsoft Academic Search

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.

Alisdair Mcneill; Patrick F. Chinnery

2011-01-01

263

Archaeometallurgy of Iron and Steel  

Microsoft Academic Search

century in some areas. At higher temperatures (1300°-1600°), carbon diffuses in the iron and the melting occurs. The product is cast iron that can be moulded but is too brittle to be hammered. It is necessary to remelt the alloy in an oxygen-rich atmosphere to reduce the carbon content (finery process). Then, the metal can be shaped by hammering. This

Vincent Serneels

264

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

265

Internal regulation of iron absorption  

Microsoft Academic Search

MCCANCE and Widdowson1 concluded that body iron content is regulated by variation in the amount absorbed and not by variation in excretion, and many workers have since attempted to define the factors which relate iron absorption to the needs of the body. Although there is a large body of data on the intracellular mechanisms of absorption2 this has not advanced

I. Cavill; M. Worwood; A. Jacobs

1975-01-01

266

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

267

Exploring Mercury. The iron planet  

Microsoft Academic Search

How did Mercury get such an enormous iron core? Why is its tectonic framework so different from any other planet or satellite? What is its crystal composition? Why is the crust so depleted in iron when the interior is so rich in that element? What are the polar deposits? Where do the elements in the exosphere come from? Mercury is

Robert G. Strom; Ann L. Sprague

2003-01-01

268

Viscosity of Iron  

NASA Astrophysics Data System (ADS)

Knowledge of the viscosity of fluid iron is necessary for a reasonable description of Earth's core, the geodynamo, and more generally for evaluation of planetary evolution scenarios. Direct measurement of viscosity under core conditions is not immediately possible. Several high-pressure experiments report viscosities (to 9 GPa), or self-diffusivities (to 20 GPa); viscosities can be inferred from the latter via the Stokes-Einstein relation. We show that these experiments do not agree with each other, nor do they agree with the strong systematic correlation between entropy and viscosity observed in other liquid metals. Iron's viscosity (and/or self-diffusivity) has also been simulated under core conditions but not at pressures for which data exist. Entropies for the simulated fluids, needed for evaluation of systematic correlations, have not been reported. Possible paths forward include new low pressure measurements with improved experimental control, measurement of self-diffusion in the laser-heated diamond-anvil cell, use of x-ray determined radial distribution functions to estimate entropies of the fluids at high pressures, all backed by simulations under appropriate experimental conditions.

Abramson, E.; Brown, J.

2010-12-01

269

Comparison of injectable iron complexes in their ability to iron load tissues and to induce oxidative stress  

Microsoft Academic Search

Iron and copper homeostasis have been studied in various tissues after iron-loading with the polynuclear ferric hydroxide carbohydrate complexes, iron dextran, iron polymaltose, iron sucrose and iron gluconate for four weeks. There were significant increases in the iron content of the different rat tissues compared to controls, with the exception of the brain, which showed no change in its iron

R. Legssyer; P. Geisser; Harry McArdle; R. R. Crichton; R. J. Ward

2003-01-01

270

Iron and Mechanisms of Neurotoxicity  

PubMed Central

The accumulation of transition metals (e.g., copper, zinc, and iron) and the dysregulation of their metabolism are a hallmark in the pathogenesis of several neurodegenerative diseases. This paper will be focused on the mechanism of neurotoxicity mediated by iron. This metal progressively accumulates in the brain both during normal aging and neurodegenerative processes. High iron concentrations in the brain have been consistently observed in Alzheimer's (AD) and Parkinson's (PD) diseases. In this connection, metalloneurobiology has become extremely important in establishing the role of iron in the onset and progression of neurodegenerative diseases. Neurons have developed several protective mechanisms against oxidative stress, among them, the activation of cellular signaling pathways. The final response will depend on the identity, intensity, and persistence of the oxidative insult. The characterization of the mechanisms mediating the effects of iron-induced increase in neuronal dysfunction and death is central to understanding the pathology of a number of neurodegenerative disorders.

Salvador, Gabriela A.; Uranga, Romina M.; Giusto, Norma M.

2011-01-01

271

Iron abundance in galaxy clusters  

NASA Astrophysics Data System (ADS)

Up to now, there are 22 clusters of galaxies for which reliable measures of both gas temperature and iron line equivalent width are available. The authors derive the variation of the iron line equivalent width with the temperature. The cluster iron abundance can be deduced from the comparison between the measurements and the computations. Its value appears to be universal, 0.53±0.03 (1?) solar value. Gas masses in clusters, and thus iron masses are shown to vary as N02.4±0.6, where N0 is the central number of galaxies. It is confirmed that gas masses are proportional to virial masses, with Mvirial = 10 Mgas = 1.5×104Miron. Implications of such relations in terms of observable gas quantities, galaxy formation and iron origin are briefly discussed.

Rothenflug, R.; Arnaud, M.

1985-03-01

272

Cellular distribution and localisation of iron in adult rat brain (substantia nigra)  

NASA Astrophysics Data System (ADS)

Iron appears to be one of the main factors in the metal induced neurodegeneration. Quantitative information on cellular, sub-cellular and cell specific distributions of iron is therefore important to assess. The investigations reported here were carried out on a brain from an adult rat. Therefore, 6 ?m thick embedded, unstained brain sections containing the midbrain (substantia nigra, SN) were analysed. Particle induced X-ray emission (PIXE) using a focussed proton beam (beam diameter app. 1 ?m) was performed to determine the quantitative iron content on a cellular and sub-cellular level. The integral analysis shows that the iron content in the SN pars reticulata is twice as high than in the SN pars compacta. The analysis of the iron content on the cellular level revealed no remarkable differences between glia cells and neurons. This is in contrast to other studies using staining techniques.

Meinecke, Ch.; Morawski, M.; Reinert, T.; Arendt, T.; Butz, T.

2006-08-01

273

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

274

Disorders of iron metabolism. Part 1: molecular basis of iron homoeostasis  

Microsoft Academic Search

Iron functionsIron is an essential micronutrient, as it is required for satisfactory erythropoietic function, oxidative metabolism and cellular immune response.Iron physiologyAbsorption of dietary iron (1–2 mg\\/day) is tightly regulated and just balanced against iron loss because there are no active iron excretory mechanisms. Dietary iron is found in haem (10%) and non-haem (ionic, 90%) forms, and their absorption occurs at

Manuel Muñoz; José Antonio García-Erce; Ángel Francisco Remacha

2010-01-01

275

Microorganisms pumping iron: anaerobic microbial iron oxidation and reduction.  

PubMed

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 for iron-reducing microorganisms. Given that iron is the fourth most abundant element in the Earth's crust, iron redox reactions have the potential to support substantial microbial populations in soil and sedimentary environments. As such, biological iron apportionment has been described as one of the most ancient forms of microbial metabolism on Earth, and as a conceivable extraterrestrial metabolism on other iron-mineral-rich planets such as Mars. Furthermore, the metabolic versatility of the microorganisms involved in these reactions has resulted in the development of biotechnological applications to remediate contaminated environments and harvest energy. PMID:16980937

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

2006-10-01

276

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

277

Pumping iron: mechanisms for iron uptake by Campylobacter.  

PubMed

Campylobacter requires iron for successful colonization of the host. In the last 7 years, a wealth of data has been generated allowing detailed molecular characterization of Campylobacter iron-uptake systems. Several exogenous siderophores have been identified as sources of ferric iron for Campylobacter. Ferri-enterochelin uptake requires both the outer-membrane receptor protein CfrA and the inner-membrane ABC transporter system CeuBCDE. Ferrichrome has been shown to support growth of some Campylobacter jejuni strains and the presence of homologues of Escherichia coli fhuABD genes was proposed; the Cj1658-Cj1663 system appears to be involved in the uptake of ferri-rhodotorulic acid. In addition to siderophores, the importance of host iron sources was highlighted by recent studies demonstrating that C. jejuni can exploit haem compounds and the transferrins using ChuABCDZ and Cj0173c-Cj0178, respectively. An additional putative receptor, Cj0444, present in some, but not all, strains has not yet been characterized. Following diffusion through the outer membrane, inner-membrane transport of ferrous iron can occur via the FeoB protein. While it may be assumed that all systems are not essential, there is growing evidence supporting the need for multiple iron-uptake systems for successful host colonization by Campylobacter. In light of this, comparative molecular characterization of iron systems in all Campylobacter strains is necessary to gain further insight into the pathogenesis of members of this genus. PMID:19696110

Miller, Claire E; Williams, Peter H; Ketley, Julian M

2009-08-20

278

Normal Iron Metabolism and the Pathophysiology of Iron Overload Disorders  

PubMed Central

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

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

2006-01-01

279

TCDD, dietary iron and hepatic iron distribution in female rats  

SciTech Connect

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a prototype for a large group of halogenated aromatic hydrocarbons, and is the most potent of these compounds. TCDD is an environmental pollutant with exceptional toxicity for certain mammalian and avian species. The liver is one of the principal target organs affected by TCDD in the rat and other laboratory species. TCDD induces many functional, biochemical and pathological changes, including altered lipid metabolism in the liver. Ferrous iron plays an important role in the initiation of lipid peroxidation. A proposed mechanism for the production of liver injury in chronic iron overload is that organelle damage leading to cell death occurs as a result of membrane lipid peroxidation initiated and promoted by intracellular iron. The presence of iron in subcellular fractions in vitro may catalyze lipid peroxidation and produce membrane damage. There is evidence for the occurrence of hepatic lipid peroxidation after TCDD administration. The purpose of this study was to determine if TCDD induced lipid peroxidation was associated with an increase in the iron content of liver and its subcellular fractions. The effect of TCDD administration on the iron content of whole homogenate, microsomes, mitochondria, and cytosol of livers of female rats fed defined diets containing deficient, normal and excessive levels of iron for 17, 24 and 31 days was investigated.

Al-Bayati, Z.A.F.; Stohs, S.J.; Al-Turk, W.A.

1987-02-01

280

Iron metabolism: current facts and future directions.  

PubMed

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

Tandara, Leida; Salamunic, Ilza

2012-01-01

281

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

282

SNAPing Coronal Iron  

NASA Astrophysics Data System (ADS)

This is a Snapshot Survey to explore two forbidden lines of highly ionized iron in late-type coronal sources. Fe XII 1349 {T 2 MK} and Fe XXI 1354 {T 10 MK} - well known to Solar Physics - have been detected in about a dozen cool stars, mainly with HST/STIS. The UV coronal forbidden lines are important because they can be observed with velocity resolution of better than 15 km/s, whereas even the state-of-the-art X-ray spectrometers on Chandra can manage only 300 km/s in the kilovolt band where lines of highly ionized iron more commonly are found. The kinematic properties of hot coronal plasmas, which are of great interest to theorists and modelers, thus only are accessible in the UV at present. The bad news is that the UV coronal forbidden lines are faint, and were captured only in very deep observations with STIS. The good news is that 3rd-generation Cosmic Origins Spectrograph, slated for installation in HST by SM4, in a mere 25 minute exposure with its G130M mode can duplicate the sensitivity of a landmark 25-orbit STIS E140M observation of AD Leo, easily the deepest such exposure of a late-type star so far. Our goal is to build up understanding of the properties of Fe XII and Fe XXI in additional objects beyond the current limited sample: how the lineshapes depend on activity, whether large scale velocity shifts can be detected, and whether the dynamical content of the lines can be inverted to map the spatial morphology of the stellar corona {as in "Doppler Imaging''}. In other words, we want to bring to bear in the coronal venue all the powerful tricks of spectroscopic remote sensing, well in advance of the time that this will be possible exploiting the corona's native X-ray radiation. The 1290-1430 band captured by side A of G130M also contains a wide range of key plasma diagnostics that form at temperatures from below 10,000 K {neutral lines of CNO}, to above 200,000 K {semi-permitted O V 1371}, including the important bright multiplets of C II at 1335 and Si IV at 1400; yielding a diagnostic gold mine for the subcoronal atmosphere. Because of the broad value of the SNAP spectra, beyond the coronal iron project, we waive the normal proprietary rights.;

Ayres, Thomas

2008-07-01

283

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

284

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

285

Metallurgy Beyond Iron  

NASA Astrophysics Data System (ADS)

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

Gallino, Isabella; Busch, Ralf

2009-08-01

286

Iron loss analysis in linear dc motor  

SciTech Connect

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

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

1999-09-01

287

Iron loss analysis in linear dc motor  

Microsoft Academic Search

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

M. Hippner; H. Yamada; T. Mizuno

1999-01-01

288

Iron acquisition by Neisseria meningitidis in vitro.  

PubMed Central

Assays employing iron-limited solid and liquid, defined and complex media were devised to test the iron requirements of Neisseria meningitidis. A variety of tests yielded no evidence for the secretion of a soluble iron-binding substance (siderophore) by the meningococci. The meningococci were unable to use iron bound to some common hydroxamate- and catechol-type siderophores or even compete with them for iron in the growth medium. A total of 20 strains of meningococci, differing widely in their virulence for mice, were similar in ability to acquire iron from a variety of iron-containing substances; the iron in such compounds as hog gastric mucin, citrate, hemoglobin, and myoglobin was easily acquired, whereas the iron in compounds such as ferrioxamine B, ferrichrome,ferritin, Imferon, cytochrome c, FePO4, and [Fe(OH)3]n was not readily available. No correlation was noted between the ability of particular strains to obtain iron from compounds and virulence in mice. Iron complexed or chelated with a number of metabolic organic acids, polyphosphates, and several synthetic polycarboxylic acids was readily available to all strains, even though some of the compounds used had high effective binding constants for iron and all were in 3- or 10-fold molar excess over the iron present. The addition of some of these iron-complexing substances (e.g., citrate and pyrophosphate) in iron-free form made many biologically important iron compounds that are normally inaccessible to the meningococci readily available. Images Fig. 1

Archibald, F S; DeVoe, I W

1980-01-01

289

Iron Oxide Based High Temperature Desulfurization Sorbent  

Microsoft Academic Search

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

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

2009-01-01

290

Iron incorporation and post-malaria anaemia  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

291

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

292

Acid mine drainage biogeochemistry at Iron Mountain, California  

Microsoft Academic Search

: The Richmond Mine at Iron Mountain, Shasta County, California, USA provides an excellent opportunity to study the chemical and biological controls on acid mine drainage (AMD) generation in situ, and to identify key factors controlling solution chemistry. Here we integrate four years of field-based geochemical data with 16S rRNA gene clone libraries and rRNA probe-based studies of microbial population

Gregory K. Druschel; Brett J. Baker; Thomas M. Gihring; Jillian F. Banfield

2004-01-01

293

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

294

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

Code of Federal Regulations, 2012 CFR

...malleable iron. (a) The low ductility of cast iron and malleable iron should be recognized and the use of these metals where shock loading may occur should be avoided. Cast iron and malleable iron components shall not be used at temperatures...

2012-10-01

295

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

Code of Federal Regulations, 2011 CFR

...malleable iron. (a) The low ductility of cast iron and malleable iron should be recognized and the use of these metals where shock loading may occur should be avoided. Cast iron and malleable iron components shall not be used at temperatures...

2011-10-01

296

Carbohydrate Metabolism of Iron-Rich and Iron-Poor Staphylococcus aureus  

Microsoft Academic Search

SUMMARY Comparative studies were made of the metabolic activities of a strain of Staphylococcus aureus grown in iron-poor and iron-rich trypticase medium, with and without glucose. Four nutritionally distinctive types of organisms were produced : iron-rich without glucose (Fe + G - ) ; iron- poor without glucose (Fe - G - ) ; iron-rich with glucose (Fe + G

T. S. THEODORE; A. L. SCHADE

1965-01-01

297

The role of desferrioxamine chelatable iron in rat liver mitochondrial dysfunction in chronic dietary iron overload  

Microsoft Academic Search

Lipid peroxidation and organelle dysfunction are important factors in hepatic iron toxicity. The form of the intracellular iron responsible for these abnormalities is still unknown. In order to investigate the iron species inducing cell injury, the level of chelatable iron in the liver mitochondria isolated from rats fed a 2.5% carbonyl iron diet for 12 weeks was measured by EPR

Daniela Ceccarelli; A. V. Kozlov; D. Gallesi; A. Tomasi; F. Giovannini; A. Masini

1997-01-01

298

Safety and Efficacy of Iron Sucrose in Patients Sensitive to Iron Dextran: North American Clinical Trial  

Microsoft Academic Search

Sensitivity to iron dextran is a potent obstacle to maintaining optimum iron status in patients with dialysis-associated anemia. As part of the North American clinical trials for iron sucrose injection, we examined the effect of intravenous (IV) iron sucrose in 23 hemodialysis patients with documented sensitivity to iron dextran, ongoing epoetin alfa therapy, and below-target-range hemoglobin (Hgb) levels (

David B. Van Wyck; Guilio Cavallo; Bruce S. Spinowitz; Rohini Adhikarla; Suzanne Gagnon; Chaim Charytan; Nathan Levin

2000-01-01

299

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

Code of Federal Regulations, 2010 CFR

...2009-10-01 false Service lines: Cast iron and ductile iron. 192.373 Section 192.373 Transportation... § 192.373 Service lines: Cast iron and ductile iron. (a) Cast or ductile iron pipe less than 6 inches (152...

2009-10-01

300

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

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Service lines: Cast iron and ductile iron. 192.373 Section 192.373 Transportation... § 192.373 Service lines: Cast iron and ductile iron. (a) Cast or ductile iron pipe less than 6 inches (152...

2010-10-01

301

Iron and lactoferrin in milk of anemic mothers given iron supplements  

Microsoft Academic Search

The factors regulating concentrations of iron and iron-binding proteins in milk are incompletely known. Since anemic women usually are given iron supplements, we have evaluated the effect of this practice on iron and lactoferrin levels in milk. Lactating Peruvian mothers (n = 29) were studied during the first month of lactation. Lactoferrin and iron in milk were analyzed at 2

Nelly Zavaleta; Jose Nombera; Rafael Rojas; Leif Hambraeus; Johannes Gislason; Bo Lönnerdal

1995-01-01

302

Austempered ductile iron process development  

NASA Astrophysics Data System (ADS)

Pressure from imports and material substitution has severly affected demand for domestic iron industry products. It is estimated that the potential market for Austempered Ductile Iron (ADI) is as large as the market for carburized and/or through hardened forgings. The primary interest in ADI is generated by the economics of process. Improved machinability and reduced processing costs as well as interesting physical properties has created an enormous interest in all metalworking industries towards ADI. The development of gas-fired austempering processes and resoluton of technical and economic uncertainities concerning the process will help improve the outlook for iron founderies.

Gupta, C. D.; Keough, J. R.; Pramstaller, D. M.

1986-11-01

303

Magnetic study of iron sorbitol  

NASA Astrophysics Data System (ADS)

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

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

2002-09-01

304

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

305

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

306

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

307

Synthesis and magnetic properties of iron-iron oxide nanoparticles  

Microsoft Academic Search

Monodisperse magnetic nanoparticles are of much interest for data storage and biomedical applications as well as for studies of the fundamental characteristics of magnetism on small length scales. In light of this attention, we have been investigating the properties of iron-iron oxide nanoparticles, prepared by modifying a recently developed solvent-based synthesis method that produces particles of well-defined size [1]. By

Anna Clausen; Yumi Ijiri

2004-01-01

308

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

309

FOLLOW-UP OF A RANDOMIZED CONTROLLED TRIAL OF IRON-FORTIFIED (12.7 MG/L) VS. LOW-IRON (2.3 MG/L) INFANT FORMULA: DEVELOPMENTAL OUTCOME AT 10 YEARS  

PubMed Central

Objective To assess long-term developmental outcome in children who received iron-fortified or low-iron formula. Design Follow-up at 10 years of randomized controlled trial (1991–1994) of 2 levels of formula iron. Examiners blind to group. Setting Urban areas around Santiago, Chile. Participants Original study enrolled healthy full-term infants in community clinics; 835 completed the trial. At 10 years, 573 were assessed (57%). Intervention Iron-fortified (12.7 mg/l) or low-iron (2.3 mg/l) formula from 6 to 12 months. Main Outcome Measures IQ, spatial memory, arithmetic achievement, visual-motor integration, visual perception, and motor functioning. We used covaried regression to compare iron-fortified and low-iron groups and consider hemogobin (HB) prior to randomization and sensitivity analyses to identify 6-month HB at which groups diverged in outcome. Results Compared to low-iron, the iron-fortified group scored lower on every 10-year outcome (significant for spatial memory, visual-motor integration; suggestive for IQ, arithmetic, visual perception, motor coordination; 1.4 – 4.6 points lower, effect sizes 0.13 – 0.21). Children with high 6-month HB (> 128 g/l) showed poorer outcome on these measures if they received iron-fortified formula (10.7 – 19.3 points lower; large effect sizes, 0.85 – 1.36); those with low HB (< 105 g/l) showed better outcome (2.6 – 4.5 points higher; small but significant effects, 0.22 – 0.36). High HB represented 5.5% of sample (n = 26); low HB, 17.0% (n = 87). Conclusions Long-term development may be adversely affected in infants with high HB who receive 12.7 mg/l iron-fortified formula. Optimal amounts of iron in infant formula warrant further study.

Lozoff, Betsy; Castillo, Marcela; Clark, Katy M.; Smith, Julia B.

2012-01-01

310

Integrated economics  

SciTech Connect

This article offers ideas for evaluating integrated solid waste management systems through the use of a conceptual cost overview. The topics of the article include the integrated solid waste management system; making assumptions about community characteristics, waste generation rates, waste collection responsibility, integrated system components, sizing and economic life of system facilities, system implementation schedule, facility ownership, and system administration; integrated system costs; integrated system revenues; system financing; cost projections; and making decisions.

Bratton, T.J. (Gershman, Brickner and Bratton Inc., Falls Church, VA (United States))

1992-09-01

311

Acquisition of Iron by Gardnerella vaginalis  

PubMed Central

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

Jarosik, Gregory P.; Land, Carol Beth; Duhon, Patrice; Chandler, Roderick; Mercer, Tammy

1998-01-01

312

Mitochondrial iron transport and homeostasis in plants  

PubMed Central

Iron (Fe) is an essential nutrient for plants and although the mechanisms controlling iron uptake from the soil are relatively well understood, comparatively little is known about subcellular trafficking of iron in plant cells. Mitochondria represent a significant iron sink within cells, as iron is required for the proper functioning of respiratory chain protein complexes. Mitochondria are a site of Fe–S cluster synthesis, and possibly heme synthesis as well. Here we review recent insights into the molecular mechanisms controlling mitochondrial iron transport and homeostasis. We focus on the recent identification of a mitochondrial iron uptake transporter in rice and a possible role for metalloreductases in iron uptake by mitochondria. In addition, we highlight recent advances in mitochondrial iron homeostasis with an emphasis on the roles of frataxin and ferritin in iron trafficking and storage within mitochondria.

Jain, Anshika; Connolly, Erin L.

2013-01-01

313

Membrane development in the cyanobacterium, Anacystis nidulans, during recovery from iron starvation  

SciTech Connect

Deprivation of iron from the growth medium results in physiological as well as structural changes in the unicellular cyanobacterium Anacystis nidulans R2. Important among these changes are alterations in the composition and function of the photosynthetic membranes. Room-temperature absorption spectra of iron-starved cyanobacterial cells show a chlorophyll absorption peak at 672 nanometers, 7 nanometers blue-shifted from its normal position at 679 nanometers. Iron-starved cells have decreased amounts of chlorophyll and phycobilins. Their fluorescence spectra (77K) have one prominent chlorophyll emission peak at 684 nanometers as compared to three peaks at 687, 696, and 717 nanometers from normal cells. Chlorophyll-protein analysis of iron-deprived cells indicated the absence of high molecular weight bands. Addition of iron to iron-starved cells induced a restoration process in which new components were initially synthesized and integrated into preexisting membranes; at later times, new membranes were assembled and cell division commenced. Synthesis of chlorophyll and phycocyanins started almost immediately after the addition of iron. The origin of the fluorescence emission at 687 and 696 nanometers is discussed in relation to the specific chlorophyll-protein complexes formed during iron reconstitution. 26 references, 2 figures, 1 table.

Pakrasi, H.B.; Goldenberg, A.; Sherman, L.A.

1985-09-01

314

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

PubMed

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

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

2013-04-18

315

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

316

Correlation, magnetization and conduction in iron pnictides and iron chalcogenides  

NASA Astrophysics Data System (ADS)

By combining density functional theory (DFT) and dynamical mean field theory (DMFT), we study the electronic properties of iron pnictides and iron chalcogenides in both the paramagnetic and magnetic states. With ab initio derived realistic Coulomb interaction U and Hund's exchange coupling J, we find detailed agreements bewtween our calculations and many experimental observations in these compounds, including ARPES, magnetic properties, optical conductivity and anisotropy, and so on, WITHOUT any adjustment such as shifting of atomic positions, Fermi level and bands and renormalizations of bands which are commonly needed in DFT calculations in order to compare with experiments. Our theory explains the origin of the different magnetizations in FeTe and other iron pnictides and provides a unique physical picture. We find that in the magnetic phase of the iron pnictides, both the spin and the orbital polarization are strongly energy dependent. The spin polarization becomes weaker around Fermi level when the orbital polarization is stronger and vice verse at high energies. We stress on the role of the Hund's J rather than the Coulomb U and show how the iron pnictides and iron chalcogenides differ from other compounds.

Yin, Zhiping; Haule, Kristjan; Kotliar, Gabriel

2011-03-01

317

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

318

Iron overload and toxicity: implications for anesthesiologists.  

PubMed

Conditions leading to iron overload range from rare hereditary disorders to more common medical conditions associated with chronic blood transfusions. Iron overload has deleterious effects on various vital organs (eg, liver, heart, and endocrine glands). Serum ferritin (in conjunction with transferrin saturation) is the most widely used test to evaluate iron burden and to screen for iron overload. The management plan should be adjusted to account for iron overload and potential consequences of liver, heart, and other organ involvement. PMID:22658368

Shander, Aryeh; Berth, Ulrike; Betta, Joanne; Javidroozi, Mazyar

2012-05-31

319

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.

Welbon, William W. (Belleair, FL)

1983-01-01

320

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

321

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.

Not Available

1982-03-06

322

Zinc Protoporphyrin and Iron Deficient Erythropoiesis  

Microsoft Academic Search

Iron-deficient erythropoiesis may occur in patients with adequate levels of storage iron as well as those with tissue iron deficiency. Here we compare two methods of detecting iron-deficient erythropoiesis. The measurement of percent hypochromic cells in the full blood count provides a direct indicator of iron-deficient erythropoiesis. The zinc protoporphyrin (ZPP) determination is simple, precise and reproducible, and also appears

Sally Garrett; Mark Worwood

1994-01-01

323

A Possible Mechanism of Iron Neurotoxicity  

Microsoft Academic Search

Iron-dependent microsomal lipid peroxidation and catechol-iron (copper-induced lipid peroxidation have been studied to prove possible nigrostriatal cell damage. Iron-dependent microsomal lipid peroxidation could be initiated by reduced irons coordinated with phosphate moieties in the membranes and significantly inhibited by copper salicylate (hydrophobic and permeable O2-scavenger) and desferrioxamine (a powerful iron-chelating agent), but not by SOD. Ferric or cupric ion significantly

Minora Nakano

1993-01-01

324

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

325

Neutron scattering of iron-based superconductors  

SciTech Connect

Low-energy spin excitations have been studied on polycrystalline LaFeAsO{sub 1-x}F{sub x} samples by inelastic neutron scattering. The Q-integrated dynamical spin susceptibility {chi}{double_prime}({omega}) of the superconducting samples is found to be comparable to that of the magnetically ordered parent sample. On the other hand, {chi}{double_prime}({omega}) almost vanishes at x = 0.158, where the superconducting transition temperature T{sub c} is suppressed to 7 K. In addition, {chi}{double_prime}({omega}) in optimally doped LaFeAsO{sub 0.918}F{sub 0.082} with T{sub c} = 29 K exhibits a spin resonance mode. The peak energy, E{sub res}, when scaled by k{sub B}T{sub c} is similar to the value of about 4.7 reported in other high-T{sub c} iron-based superconductors. This result suggests that there is intimate relationship between the dynamical spin susceptibility and high-T{sub c} superconductivity in iron-based superconductors, and is consistent with a nesting condition between Fermi surfaces at the {Gamma} and M points.

Shamoto, S [Japan Atomic Energy Agency (JAEA); Wakimoto, S [Japan Atomic Energy Agency (JAEA); Kodama, K. [Japan Synchrotron Radiation Research Institute, SPring-8; Ishikado, Motoyuki [JAEA and JST-TRIP, Tokyo; Christianson, Andrew D [ORNL; Lumsden, Mark D [ORNL; Kajimoto, Ryoichi [JST-TRIP and J-PARC Center; Nakamura, Mitsutaka [JST-TRIP and J-PARC Center; Inamura, Yasuhiro [JST-TRIP and J-PARC Center; Arai, Masatoshi [Japan Atomic Energy Agency (JAEA); Kakurai, K. [Japan Atomic Energy Agency (JAEA); Esaka, Fumitaka [Japan Atomic Energy Agency (JAEA); Iyo, Akira [JST-TRIP and NIAIST, Japan; Kito, Hijiri [JST-TRIP and NIAIST, Japan; Eisaki, Hiroshi [JST-TRIP and NIAIST, Japan

2011-01-01

326

Mechanism of skull formation in hot-metal-car ladles  

Microsoft Academic Search

At the Magnitogorsk Metallurgical Combine, pig iron is tapped into conventional loo-ton and 450-ton mixer ladles. However, untimely deliveries of the ladles for tapping have led to disruptions in the tapping schedule and reduced the technical-economic indices of the smelting operation. One reason for the late arrival of the ladles is the difficulty encountered in removing the shell of slag

M. N. Kurbatskii; K. N. Vdovin; V. L. Terent'ev; N. P. Sysoev; S. I. Trofimov

1997-01-01

327

Fabrication of Iron-Containing Carbon Materials from Graphite Fluoride.  

National Technical Information Service (NTIS)

Carbon materials containing iron alloy, iron metal, iron oxide or iron halide were fabricated. Typical samples of these metals were estimated to contain 1 iron atom per 3.5 to 5 carbon atoms. Those carbon materials containing iron alloy, iron metal, and/o...

C. Hung

1996-01-01

328

Iron catalyzed coal liquefaction process  

DOEpatents

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

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

1983-01-01

329

Discovery of the iron isotopes  

SciTech Connect

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

Schuh, A.; Fritsch, A.; Heim, M.; Shore, A. [National Superconducting Cyclotron Laboratory and Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Thoennessen, M., E-mail: thoennessen@nscl.msu.ed [National Superconducting Cyclotron Laboratory and Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States)

2010-11-15

330

Observing Iron Stars with Spitzer  

NASA Astrophysics Data System (ADS)

Only two so-called Iron stars exist: XX Oph and AS 325. XX Oph was first observed in 1924 by Merrill. He noted strong, doubly ionized iron emission lines were present in the spectra, thus the name iron star. AS325 was noted to be a similar type object by Howell and Bopp (1982). Further observations of both stars have led to the development of a model (Cool et al., 2005) for both stars which explains the optical emission lines and that the stars consist of two separate stars, possibly in a binary. The current model has each Iron Star composed of a Be star and a late type (supergiant) companion separated by 1-2 thousand AU. We plan to use Spitzer to observethe dust environment in the star AS325.

Thomas, Beth; Howell, Steve; Chapple, Lauren; Daou, Doris; Rapp, Steve; Roelofson, Theresa; Weehler, Cindy

2005-02-01

331

Magnetic properties of iron dextran  

NASA Astrophysics Data System (ADS)

The magnetic properties of a freeze-dried iron dextran complex have been studied using Mössbauer spectroscopy and DC magnetisation. The Mössbauer spectra show superparamagnetic relaxation with the onset of superparamagnetic blocking occurring close to 120 K.

Kilcoyne, S. H.; Gorisek, A.

1998-01-01

332

Fugitive Emissions from Iron Foundries.  

National Technical Information Service (NTIS)

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

D. Wallace C. Cowherd

1979-01-01

333

Extraction of Iron with Methylethylketone.  

National Technical Information Service (NTIS)

The extraction of iron (III) with methylethylketone as solvent from hydrochloric acid solution is described, and the maximum range of acid concentration for quantitative extraction was determined. Most of the elements of the third analytical group were in...

E. Gagliardi H. P. Woess

1974-01-01

334

Iron catalyzed coal liquefaction process  

SciTech Connect

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

Garg, D.; Givens, E.N.

1983-10-25

335

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

336

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

337

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

338

Iron acquisition in Vibrio cholerae  

Microsoft Academic Search

Vibrio cholerae, the causative agent of cholera, has an absolute requirement for iron and must obtain this element in the human host as well\\u000a as in its varied environmental niches. It has multiple systems for iron acquisition, including the TonB-dependent transport\\u000a of heme, the endogenous siderophore vibriobactin and several siderophores that are produced by other microorganisms. There\\u000a is also a

Elizabeth E. Wyckoff; Alexandra R. Mey; Shelley M. Payne

2007-01-01

339

Wear resistance of ductile irons  

Microsoft Academic Search

This study was undertaken to evaluate the wear resistance of different grades of ductile iron as alterna-tives to high- tensile-\\u000a strength alloyed and inoculated gray irons and bronzes for machine- tool and high-pressure hydraulic components. Special test\\u000a methods were employed to simulate typical conditions of reciprocating sliding wear with and without abrasive- contaminated\\u000a lubricant for machine and press guideways. Quantitative

Y. S. Lerner

1994-01-01

340

Enzymes and other iron proteins  

NASA Astrophysics Data System (ADS)

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

Debrunner, Peter G.

1990-07-01

341

Iron Requirements and Adverse Outcomes  

Microsoft Academic Search

Iron deficiency continues to be one of the most prevalent nutritional deficiency diseases in the world and has a particularly\\u000a high prevalence in pregnancy. The incidence and severity are greater in developing countries but even in developed countries,\\u000a the prevalence may reach 30–40% in the third trimester. The assessment of iron status in pregnancy can be challenging due\\u000a to the

John Beard

342

A Review of the Significance of Dietary Iron on Iron Storage Phenomena.  

National Technical Information Service (NTIS)

The report reviews and assesses the possible hazard that might result from increased iron enrichment of wheat flour and flour-containing dietary items. It identifies the iron compounds of the body associated with iron storage phenomena and emphasizes the ...

C. J. Carr H. F. Sassoon J. Waddell K. D. Fisher

1972-01-01

343

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

344

Electronic structure of small iron clusters  

NASA Astrophysics Data System (ADS)

We report calculations of energy levels and the charge and spin densities for small free (not embedded) clusters of iron atoms. Our method uses spin-density-functional theory in the local approximation. Single-particle functions are expanded in a basis set of symmetrized linear combinations of Gaussian orbitals. Matrix elements of the electrostatic potential are computed with the aid of a fit to the electron density, again with the use of symmetrized combinations of Gaussian orbitals. The matrix elements of the exchange-correlation potential are evaluated by direct numerical integration using a grid developed for this purpose. The clusters considered are Fe7, Fe9, and Fe15. Our results are compared with those obtained by other calculational procedures. The ionization potential of the Fe9 cluster is determined by a transition-state calculation and is compared with experiment.

Lee, Keeyung; Callaway, Joseph; Dhar, S.

1984-08-01

345

Differences in activation of mouse hepcidin by dietary iron and parenterally administered iron dextran: compartmentalization is critical for iron sensing.  

PubMed

The iron regulatory hormone hepcidin responds to both oral and parenteral iron. Here, we hypothesized that the diverse iron trafficking routes may affect the dynamics and kinetics of the hepcidin activation pathway. To address this, C57BL/6 mice were administered an iron-enriched diet or injected i.p. with iron dextran and analyzed over time. After 1 week of dietary loading with carbonyl iron, mice exhibited significant increases in serum iron and transferrin saturation, as well as in hepatic iron, Smad1/5/8 phosphorylation and bone morphogenetic protein 6 (BMP6), and hepcidin mRNAs. Nevertheless, hepcidin expression reached a plateau afterward, possibly due to upregulation of inhibitory Smad7, Id1, and matriptase-2 mRNAs, while hepatic and splenic iron continued to accumulate over 9 weeks. One day following parenteral administration of iron dextran, mice manifested elevated serum and hepatic iron levels and Smad1/5/8 phosphorylation, but no increases in transferrin saturation or BMP6 mRNA. Surprisingly, hepcidin failed to appropriately respond to acute overload with iron dextran, and a delayed (after 5-7 days) hepcidin upregulation correlated with increased transferrin saturation, partial relocation of iron from macrophages to hepatocytes, and induction of BMP6 mRNA. Our data suggest that the physiological hepcidin response is saturable and are consistent with the idea that hepcidin senses exclusively iron compartmentalized within circulating transferrin and/or hepatocytes. PMID:22847740

Daba, Alina; Gkouvatsos, Konstantinos; Sebastiani, Giada; Pantopoulos, Kostas

2012-07-31

346

Action of chelators in iron-loaded cardiac cells: accessibility to intracellular labile iron and functional consequences  

Microsoft Academic Search

Labile iron in hemosiderotic plasma and tissue are sources of iron toxicity. We compared the iron chelators deferox- amine, deferiprone, and deferasirox as scavengers of labile iron in plasma and cardiomyocytes at therapeutic concentra- tions. This comprised chelation of labile plasma iron (LPI) in samples from thalas- semia patients; extraction of total cellular iron; accessing labile iron accumulated in organelles

Hava Glickstein; Rinat Ben El; Gabi Link; William Breuer; Abraham M. Konijn; Chaim Hershko; Hanspeter Nick; Z. Ioav Cabantchik; Charles E. Smith

2006-01-01

347

Iron status of babies born to iron- deficient anaemic mothers in an Iranian hospital  

Microsoft Academic Search

We investigated the relation between maternal anaemia and neonatal iron status in 97 mothers and their babies. Haemoglobin (Hb), serum iron, total iron binding capacity and serum ferritin were determined. Mothers were divided into 3 groups: iron-deficient anaemic (22.7%), non-anaemic iron-deficient (27.8%) and non-anaemic non-iron-deficient (49.5%). There was no significant difference in the mean ages of the 3 groups but

F. Emamghorashi; T. Heidari

2004-01-01

348

Ability of Vibrio vulnificus to obtain iron from transferrin and other iron-binding proteins  

Microsoft Academic Search

The ability of virulent and avirulent strains ofVibrio vulnificus to overcome iron limitations by using iron bound to iron-binding proteins was examined. While no strains were able to obtain iron from lactoferrin or ferritin when these proteins were not fully saturated with iron, growth was enhanced by the iron-saturated form of these proteins. None of the strains was able to

Linda M. Simpson; James D. Oliver

1987-01-01

349

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

350

Iron trafficking system in Helicobacter pylori.  

PubMed

Helicobacter pylori infections are closely associated with peptic ulcers, gastric malignancy and iron deficiency anemia. Iron is essential for almost all living organisms and the investigation of iron uptake and trafficking system is thus important to understand the pathological roles of H. pylori. Up to now, the iron trafficking system of H. pylori is not yet fully clear and merits further efforts in this regards. The available information about iron uptake and regulation has been discussed in this concise review, such as FeoB in ferrous transportation, FrpB2 in hemoglobin uptake, HugZ in heme processing, virulence factors (VacA and CagA) in transferrin utilization, Pfr and NapA in iron storage and Fur in iron regulation. The identified iron trafficking system will help us to understand the pathological roles of H. pylori in the various gastric diseases and iron deficiency anemia and stimulates further development of effective anti-bacterial drugs. PMID:22127376

Ge, Ruiguang; Sun, Xuesong

2011-11-30

351

Synthesis, properties, and applications of iron nanoparticles.  

SciTech Connect

Iron, the most ubiquitous of the transition metals and the fourth most plentiful element in the Earths crust, is the structural backbone of our modern infrastructure. It is therefore ironic that as a nanoparticle, iron has been somewhat neglected in favor of its own oxides, as well as other metals such as cobalt, nickel, gold, and platinum. This is unfortunate, but understandable. Irons reactivity is important in macroscopic applications (particularly rusting), but is a dominant concern at the nanoscale. Finely divided iron has long been known to be pyrophoric, which is a major reason that iron nanoparticles have not been more fully studied to date. This extreme reactivity has traditionally made iron nanoparticles difficult to study and inconvenient for practical applications. Iron however has a great deal to offer at the nanoscale, including very potent magnetic and catalytic properties. Recent work has begun to take advantage of irons potential, and work in this field appears to be blossoming.

Huber, Dale L.

2005-01-01

352

Synthesis, properties, and applications of iron nanoparticles.  

PubMed

Iron, the most ubiquitous of the transition metals and the fourth most plentiful element in the Earth's crust, is the structural backbone of our modern infrastructure. It is therefore ironic that as a nanoparticle, iron has been somewhat neglected in favor of its own oxides, as well as other metals such as cobalt, nickel, gold, and platinum. This is unfortunate, but understandable. Iron's reactivity is important in macroscopic applications (particularly rusting), but is a dominant concern at the nanoscale. Finely divided iron has long been known to be pyrophoric, which is a major reason that iron nanoparticles have not been more fully studied to date. This extreme reactivity has traditionally made iron nanoparticles difficult to study and inconvenient for practical applications. Iron however has a great deal to offer at the nanoscale, including very potent magnetic and catalytic properties. Recent work has begun to take advantage of iron's potential, and work in this field appears to be blossoming. PMID:17193474

Huber, Dale L

2005-05-01

353

Iron bioavailability and dietary reference values.  

PubMed

Iron differs from other minerals because iron balance in the human body is regulated by absorption only because there is no physiologic mechanism for excretion. On the basis of intake data and isotope studies, iron bioavailability has been estimated to be in the range of 14-18% for mixed diets and 5-12% for vegetarian diets in subjects with no iron stores, and these values have been used to generate dietary reference values for all population groups. Dietary factors that influence iron absorption, such as phytate, polyphenols, calcium, ascorbic acid, and muscle tissue, have been shown repeatedly to influence iron absorption in single-meal isotope studies, whereas in multimeal studies with a varied diet and multiple inhibitors and enhancers, the effect of single components has been, as expected, more modest. The importance of fortification iron and food additives such as erythorbic acid on iron bioavailability from a mixed diet needs clarification. The influence of vitamin A, carotenoids, and nondigestible carbohydrates on iron absorption and the nature of the "meat factor" remain unresolved. The iron status of the individual and other host factors, such as obesity, play a key role in iron bioavailability, and iron status generally has a greater effect than diet composition. It would therefore be timely to develop a range of iron bioavailability factors based not only on diet composition but also on subject characteristics, such as iron status and prevalence of obesity. PMID:20200263

Hurrell, Richard; Egli, Ines

2010-03-03

354

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

355

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

PubMed

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

Ahluwalia, Namanjeet

2002-05-01

356

MCNP ENDF/B-VI iron benchmark calculations  

SciTech Connect

Four iron shielding benchmarks have been calculated, we believe for the first time, with MCNP4A and its new ENDF/B-VI library. These calculations are part of the Hiroshima/Nagasaki dose re-evaluation for the National Academy of Sciences and the Defense Nuclear Agency. We believe these calculations are significant because they validate MCNP and the new ENDF/B-VI libraries. These calculations are compared with experimental results, as well as with calculations from other data sets, including ENDF/B-IV, ENDF/B-V, and the recommended MCNP data library (a T-2 evaluation). The first iron shielding benchmarks are the Livermore pulsed sphere experiments from the 1960s. These consist of a 14-MeV pulsed deuterium-tritium (D-T) neutron source in spheres of different materials and thicknesses and measured with time-of-flight detectors. The iron experiments were for iron spheres of 0.9 and 4.8 mean free paths (mfp). In addition to comparing the detailed energy spectrum from 2 to 16 MeV, the integrals of emerging neutrons are tabulated in two bins: 2 to 16 MeV and 12 to 16 MeV. These data are presented.

Court, J.D.; Hendricks, J.S. [Los Alamos National Lab., NM (United States)

1994-12-31

357

Reversing productivity losses from iron deficiency: the economic case.  

PubMed

Iron deficiency anemia (IDA) depresses human productivity, but policymakers do not generally view this effect as an impediment to sustained economic growth. Economic logic should be enfolded in public advocacy for increased investment in the prevention and control of IDA. This paper argues that integrated strategies are required, with each intervention clearly related to particular groups at risk, and benefits carefully calibrated with costs. Protecting women's lives through supplementation has the first call on public resources, but the most productive investments reduce population prevalence at least cost, and these lie with food-based approaches within the competence of the processed food and seed industries. The public and private sectors must embark on modernization of the food industry in developing countries and reorientation of the international agricultural research complex so that iron-enriched essential foods will be affordable and accessible to the poor, especially children. The costs of IDA, the availability of cost-effective strategies and the benefits of sustained iron nutrition improvement to individuals, families and nations are reviewed. The roles of iron supplementation, food fortification, plant breeding and biotechnology, both actual and imminent, are described. The paper concludes that a recast Green Revolution directed toward dietary quality may be the key to enhancing the learning and earning capacity of young people in the developing world. PMID:11925484

Hunt, Joseph M

2002-04-01

358

Iron and Porphyrin Trafficking in Heme Biogenesis*  

PubMed Central

Iron is an essential element for diverse biological functions. In mammals, the majority of iron is enclosed within a single prosthetic group: heme. In metazoans, heme is synthesized via a highly conserved and coordinated pathway within the mitochondria. However, iron is acquired from the environment and subsequently assimilated into various cellular pathways, including heme synthesis. Both iron and heme are toxic but essential cofactors. How is iron transported from the extracellular milieu to the mitochondria? How are heme and heme intermediates coordinated with iron transport? Although recent studies have answered some questions, several pieces of this intriguing puzzle remain unsolved.

Schultz, Iman J.; Chen, Caiyong; Paw, Barry H.; Hamza, Iqbal

2010-01-01

359

Iron, brain ageing and neurodegenerative disorders.  

PubMed

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 iron can increase oxidative-stress induced neuronal vulnerability, and iron accumulation might increase the toxicity of environmental or endogenous toxins. By studying the accumulation and cellular distribution of iron during ageing, we should be able to increase our understanding of these neurodegenerative disorders and develop new therapeutic strategies. PMID:15496864

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

2004-11-01

360

Size-fractionated iron distributions and iron-limitation processes in the subarctic NW Pacific  

NASA Astrophysics Data System (ADS)

Comparison of vertical profiles of size-fractionated iron between the western and eastern subarctic North Pacific clearly showed higher labile particulate iron concentrations towards the west and this result strongly supports the higher iron supply in the western region. Additionally, the results of the SEEDS experiment, the first meso-scale iron enrichment experiment in the subarctic North Pacific, clearly showed that artificially enriched iron in the dissolved fraction (mainly in colloidal fraction) was rapidly transformed to suspended labile particulate iron during phytoplankton growth and was retained in the surface mixed layer. Probably, this same rapid transformation process occurs naturally after sporadic atmospheric iron supply and the labile particulate iron is retained in the western region. Furthermore, this transformation process reduces dissolved concentration of iron and its bioavailability. Therefore, the transformation process is important for understanding how phytoplankton became iron limited and the biogeochemical iron cycle in the western subarctic North Pacific.

Nishioka, Jun; Takeda, Shigenobu; Kudo, Isao; Tsumune, Daisuke; Yoshimura, Takeshi; Kuma, Kenshi; Tsuda, Atsushi

2003-07-01

361

Preparation and protection of iron and iron compounds  

NASA Astrophysics Data System (ADS)

Iron, iron carbide and iron oxide nano- and micro-particles were synthesized in a hermetically sealed container using ferrocene and a mixture of ferrocene, xylene and water. The particles produced possess well expressed magnetic properties and are wrapped in a protective carbon cover. Carbon provides excellent protection against moisture and chemical influences and insures a long-lasting stability. Structural changes in the particles and their covers were examined at up to 1000 °C in vacuum and 800 °C in air, as were their stability under the influence of acids. The particles morphology was examined by scanning (SEM) and transmission electron microscopy (TEM); their chemical composition and crystal structure were studied by X-ray diffraction (XRD), Mössbauer spectroscopy and electron probe X-ray micro analysis and energy dispersive X-ray spectrometry (EDS).

Koprinarov, N.; Konstantinova, M.; Avdeev, G.; Ruskov, T.; Tzacheva, Tz

2012-03-01

362

Iron and Ferritin Levels in Saliva of Patients with Thalassemia and Iron Deficiency Anemia  

PubMed Central

Most of the techniques for measuring iron stores such as serum iron concentration, iron binding capacity, serum ferritin level, liver biopsy can be troublesome or invasive for patients with thalassemia. The salivary iron measurement could be of potential advantage being an easy and non invasive approach for diagnosis of iron deficiency and iron overload . The aim of this study was to compare the levels of iron and ferritin in saliva and serum of patients affected by thalassemia or iron deficiency anemia. For this purpose, 96 patients with iron overload (71 with thalassemia major, 10 with thalassemia intermedia and 15 with thalassemia trait), 30 patients with iron deficiency anemia, and 35 healthy children as control group were involved in this study. Their saliva and serum iron and ferritin levels were measured. Iron and ferritin levels were higher in iron overload groups than in control group and lower in iron deficiency group (p<0.05). Furthermore serum and saliva iron and ferritin levels paralleled in all groups. In conclusion, iron and ferritin saliva can be routinely used for diagnosis of both iron overload and deficiency; furthermore this procedure may be an important advantage for blood donors being easily available and not invasive.

Canatan, Duran; Akdeniz, Sevgi Kosaci

2012-01-01

363

Iron deficiency on neuronal function.  

PubMed

Because of the intrinsic ability of iron to catalyze the formation of reactive oxygen species, it has been associated with oxidative stress and neurodegenerative diseases. However, iron deficiency (ID) also negatively impacts various functions of the brain, suggesting that iron plays an important physiological role in neuronal processes such as myelination, synaptogenesis, behavior and synaptic plasticity (SP). ID not only produces changes in the hippocampus, striatum, amygdale or prefrontal cortex, it also affects the interaction among these systems. In both humans and rodents, the perturbations of these structures are associated to cognitive deficits. These cognitive alterations have been well correlated with changes in neural plasticity, the possible cellular substrate of memory and learning. Given that SP is strongly affected by early ID and the lasting-neurological consequences remain even after ID has been corrected, it is important to prevent ID as well as to seek effective therapeutic interventions that reduce or reverse the long-term effects of the ID in the nervous system. This review will give an overview of the literature on the effects of iron deficit in neuronal functions such as behavior, neurotransmission and SP. We also discuss our recent data about the possible oxidative effect of iron on the mechanisms involved in neural plasticity. PMID:22639188

Muñoz, Pablo; Humeres, Alexis

2012-05-26

364

Iron homeostasis and toxicity in retinal degeneration.  

PubMed

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 buildup 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 10 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. PMID:17921041

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

2007-08-11

365

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

366

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

2013-01-16

367

Rare causes of hereditary iron overload.  

PubMed

Iron is a vitally important element in mammalian metabolism because of its unsurpassed versatility as a biologic catalyst. However, when not appropriately shielded or when present in excess, iron plays a key role in the formation of extremely toxic oxygen radicals, which ultimately cause peroxidative damage to vital cell structures. Organisms are equipped with specific proteins designed for iron acquisition, export, transport, and storage as well as with sophisticated mechanisms that maintain the intracellular labile iron pool at an appropriate level. These systems normally tightly control iron homeostasis but their failure can lead to iron deficiency or iron overload and their clinical consequences. This review describes several rare iron loading conditions caused by genetic defects in some of the proteins involved in iron metabolism. A dramatic decrease in the synthesis of the plasma iron transport protein, transferrin, leads to a massive accumulation of iron in nonhematopoietic tissues but virtually no iron is available for erythropoiesis. Humans and mice with hypotransferrinemia have a remarkably similar phenotype. Homozygous defects in a recently identified gene encoding transferrin receptor 2 lead to iron overload (hemochromatosis type 3) with symptoms similar to those seen in patients with HFE-associated hereditary hemochromatosis (hemochromatosis type 1). Transferrin receptor 2 is primarily expressed in the liver but it is unclear how mutant forms cause iron overload. Mutations in the gene encoding the iron exporter, ferroportin 1, cause iron overload characterized by iron accumulation in macrophages yet normal plasma iron levels. Plasma iron, together with dominant inheritance, discriminates iron overload due to ferroportin mutations (hemochromatosis type 4) from hemochromatosis type 1. Heme oxygenase 1 is essential for the catabolism of heme and in the recycling of hemoglobin iron in macrophages. Homozygous heme oxygenase 1 deletion in mice leads to a paradoxical accumulation of nonheme iron in macrophages, hepatocytes, and many other cells and is associated with low plasma iron levels, anemia, endothelial cell damage, and decreased resistance to oxidative stress. A similar phenotype occurred in a child with severe heme oxygenase 1 deficiency. Recently, a mutation in the L-subunit of ferritin has been described that causes the formation of aberrant L-ferritin with an altered C-terminus. Individuals with this mutation in one allele of L-ferritin have abnormal aggregates of ferritin and iron in the brain, primarily in the globus pallidus. Patients with this dominantly inherited late-onset disease present with symptoms of extrapyramidal dysfunction. Mice with a targeted disruption of a gene for iron regulatory protein 2 (IRP2), a translational repressor of ferritin, misregulate iron metabolism in the intestinal mucosa and the central nervous system. Significant amounts of ferritin and iron accumulate in white matter tracts and nuclei, and adult IRP2-deficient mice develop a movement disorder consisting of ataxia, bradykinesia, and tremor. Mutations in the frataxin gene are responsible for Friedreich ataxia, the most common of the inherited ataxias. Frataxin appears to regulate mitochondrial iron (or iron-sulfur cluster) export and the neurologic and cardiac manifestations of Friedreich ataxia are due to iron-mediated mitochondrial toxicity. Finally, patients with Hallervorden-Spatz syndrome, an autosomal recessive, progressive neurodegenerative disorder, have mutations in a novel pantothenate kinase gene (PANK2). The cardinal feature of this extrapyramidal disease is pathologic iron accumulation in the globus pallidus. The defect in PANK2 is predicted to cause the accumulation of cysteine, which binds iron and causes oxidative stress in the iron-rich globus pallidus. PMID:12382200

Ponka, Prem

2002-10-01

368

Salmonella typhimurium Encodes a Putative Iron Transport System within the Centisome 63 Pathogenicity Island  

PubMed Central

Upon entry into the host, Salmonella enterica strains are presumed to encounter an iron-restricted environment. Consequently, these bacteria have evolved a variety of often-redundant high-affinity acquisition systems to obtain iron in this restricted environment. We have identified an iron transport system that is encoded within the centisome 63 pathogenicity island of Salmonella typhimurium. The nucleotide composition of this locus is significantly different from that of the rest of this pathogenicity island, suggesting a different ancestry and a mosaic structure for this region of the S. typhimurium chromosome. This locus, designated sit, consists of four open reading frames which encode polypeptides with extensive homology to the yfe ABC iron transport system of Yersinia pestis, as well as other ABC transporters. The sitA gene encodes a putative periplasmic binding protein, sitB encodes an ATP-binding protein, and sitC and sitD encode two putative permeases (integral membrane proteins). This operon is capable of complementing the growth defect of the enterobactin-deficient Escherichia coli strain SAB11 in iron-restricted minimal medium. Transcription of the sit operon is repressed under iron-rich growth conditions in a fur-dependent manner. Introduction of a sitBCD deletion into wild-type S. typhimurium resulted in no apparent growth defect in either nutrient-rich or minimal medium and no measurable virulence phenotype. These results further support the existence of redundant iron uptake systems in S. enterica.

Zhou, Daoguo; Hardt, Wolf-Dietrich; Galan, Jorge E.

1999-01-01

369

Do Iron Stars Really Exist?  

NASA Astrophysics Data System (ADS)

Only two stars have been classified as Iron Stars: XX Oph and AS 325. This distinction is bestowed upon them as their optical spectra consist entirely of a forest of emission lines, most of which are due to the ionized metals of iron, chromium, and titanium. Over the years, XX Oph (Merrill's iron star) and AS 325 have received various classifications including spectral types from B to M and even thought to be binary stars. Using new optical and near-IR spectroscopy we have finally observed the stellar photospheres in these two objects. They appear to be evolved stars trapped in a dense region of the Rho Oph star forming region. Taking our multi-wavelength observations plus past work by others, we have developed a new model for what these two unique objects really are.

Peña, M. A.; Cool, R. J.; Howell, S. B.; Adamson, A.

2004-12-01

370

Fracture of iron aluminide alloys  

SciTech Connect

Five heats of iron aluminide alloys have been prepared, and their impact fracture properties compared to FA-129 iron aluminide. The first was a simple ternary alloy of iron, aluminum, and chromium to match the FA-129 composition. The second was similar but with additions of zirconium and carbon. The third alloy had zirconium, carbon, niobium and molybdenum. Two heats were produced produced with reduced aluminum contents so that a disordered body-centered cubic structure would be present. The impact properties, microstructures, and fractography of these alloys were compared to FA-129. The ductile-to-brittle transition temperatures of all of the Fe{sub 3}Al alloys were similar, but the simple ternary alloy had a much higher upper-shelf energy. The reduced aluminum alloys had lower transition temperatures. The microstructures were, in general, coarse and anisotropic. The fracture processes were dominated by second-phase particles.

Alexander, D.J.; Sikka, V.K.

1992-01-01

371

Fracture of iron aluminide alloys  

SciTech Connect

Five heats of iron aluminide alloys have been prepared, and their impact fracture properties compared to FA-129 iron aluminide. The first was a simple ternary alloy of iron, aluminum, and chromium to match the FA-129 composition. The second was similar but with additions of zirconium and carbon. The third alloy had zirconium, carbon, niobium and molybdenum. Two heats were produced produced with reduced aluminum contents so that a disordered body-centered cubic structure would be present. The impact properties, microstructures, and fractography of these alloys were compared to FA-129. The ductile-to-brittle transition temperatures of all of the Fe{sub 3}Al alloys were similar, but the simple ternary alloy had a much higher upper-shelf energy. The reduced aluminum alloys had lower transition temperatures. The microstructures were, in general, coarse and anisotropic. The fracture processes were dominated by second-phase particles.

Alexander, D.J.; Sikka, V.K.

1992-08-01

372

Transferrins: iron release from lactoferrin.  

PubMed

Iron loss in vitro by the iron scavenger bovine lactoferrin was investigated in acidic media in the presence of three different monoanions (NO(3)(-), Cl(-) and Br(-)) and one dianion (SO(4)(2-)). Holo and monoferric C-site lactoferrins lose iron in acidic media (pH< or =3.5) by a four-step mechanism. The first two steps describe modifications in the conformation affecting the whole protein, which occur also with apolactoferrin. These two processes are independent of iron load and are followed by a third step consisting of the gain of two protons. This third step is kinetically controlled by the interaction with two Cl(-), Br(-) and NO(3)(-) or one SO(4)(2-). In the fourth step, iron loss is under the kinetic control of a slow gain of two protons; third-order rate-constants k(2), 4.3(+/-0.2)x10(3), 3.4(+/-0.5)x10(3), 3.3(+/-0.5)x10(3) and 1.5(+/-0.5)x10(3) M(-2) s(-1) when the protein is in interaction with SO(4)(2-), NO(3)(-), Cl(-) or Br(-), respectively. This step is accompanied by the loss of the interaction with the anions; equilibrium constant K(2), 20+/-5 mM, 1.0(+/-0.2)x10(-1), 1.5(+/-0.5)x10(-1) and 1.0(+/-0.3)x10(-1) M(2), for SO(4)(-), NO(3)(-), Cl(-) and Br(-), respectively. This mechanism is very different from that determined in mildly acidic media at low ionic strength (micro<0.5) for the iron transport proteins, serum transferrin and ovotransferrin, with which no prior change in conformation or interaction with anions is required. These differences may result from the fact that in the transport proteins, the interdomain hydrogen bonds that consolidate the closed conformation of the iron-binding cleft occur between amino acid side-chain residues that can protonate in mildly acidic media. With bovine lactoferrin, most of the interdomain hydrogen bonds involved in the C-site and one of those involved in the N-site occur between amino acid side-chain residues that cannot protonate. The breaking of the interdomain H-bond upon protonation can trigger the opening of the iron cleft, facilitating iron loss in serum transferrin and ovotransferrin. This situation is, however, different in lactoferrin, where iron loss requires a prior change in conformation. This can explain why lactoferrin does not lose its iron load in acidic media and why it is not involved in iron transport in acidic endosomes. PMID:11023790

Abdallah, F B; El Hage Chahine, J M

2000-10-20

373

Inflammation and iron deficiency in the hypoferremia of obesity  

Microsoft Academic Search

Context:Obesity is associated with hypoferremia, but it is unclear if this condition is caused by insufficient iron stores or diminished iron availability related to inflammation-induced iron sequestration.Objective:To examine the relationships between obesity, serum iron, measures of iron intake, iron stores and inflammation. We hypothesized that both inflammation-induced sequestration of iron and true iron deficiency were involved in the hypoferremia of

L B Yanoff; C M Menzie; B Denkinger; N G Sebring; T McHugh; A T Remaley; J A Yanovski

2007-01-01

374

The effect of alcohol consumption on the prevalence of iron overload, iron deficiency, and iron deficiency anemia  

Microsoft Academic Search

Background & Aims: Our aim was to investigate the relationship between alcohol consumption and iron overload, iron deficiency, or iron deficiency anemia in the U.S. population. Methods: Adult participants of the Third National Health and Nutrition Examination Survey who did not consume alcohol (n = 8839) were compared with participants who consumed ?1 (n = 4976), >1 to ?2 (n

George N. Ioannou; Jason A. Dominitz; Noel S. Weiss; Patrick J. Heagerty; Kris V. Kowdley

2004-01-01

375

Disassembling Iron Availability to Phytoplankton  

PubMed Central

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

Shaked, Yeala; Lis, Hagar

2012-01-01

376

Distribution of Iron in the Northwest Atlantic.  

National Technical Information Service (NTIS)

Samples from eleven stations in the Sargasso Sea, Slope Water, and continental shelf water of the Northwest Atlantic have been analyzed for total iron by atomic absorption spectrophotometry. Vertical profiles for iron and associated temperature and nutrie...

J. L. Symes D. R. Kester

1985-01-01

377

Characterization of iron in airborne particulate matter  

NASA Astrophysics Data System (ADS)

In this work soil samples, iron ore and airborne atmospheric particulate matter (PM) in the Metropolitan Region of Belo Horizonte (MRBH), State of Minas Gerais, Brazil, are investigated with the aim of identifying if the sources of the particulate matter are of natural origin, such as, resuspension of particles from soil, or due to anthropogenic origins from mining and processing of iron ore. Samples were characterized by powder X-ray diffraction, X-ray fluorescence and 57Fe-Mössbauer spectroscopy. The results showed that soil samples studied are rich in quartz and have low contents of iron mainly iron oxide with low crystallinity. The samples of iron ore and PM have high concentration of iron, predominantly well crystallized hematite. 57Fe-Mössbauer spectroscopy confirmed the presence of similar iron oxides in samples of PM and in the samples of iron ore, indicating the anthropogenic origin in the material present in atmosphere of the study area.

Tavares, F. V. F.; Ardisson, J. D.; Rodrigues, P. C. H.; Brito, W.; Macedo, W. A. A.; Jacomino, V. M. F.

2013-02-01

378

Thermal transport properties of grey cast irons.  

National Technical Information Service (NTIS)

Thermal diffusivity and thermal conductivity of grey cast iron have been measured as a function of graphite flake morphology, chemical composition, and position in a finished brake rotor. Cast iron samples used for this investigation were cut from ''step ...

R. L. Hecht R. B. Dinwiddie W. D. Porter H. Wang

1996-01-01

379

21 CFR 582.5375 - Iron reduced.  

Code of Federal Regulations, 2013 CFR

...AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5375 Iron reduced. (a) Product. Iron reduced. (b) Conditions of...

2013-04-01

380

Human Frataxin: Iron And Ferrochelatase Binding Surface  

SciTech Connect

The coordinated iron structure and ferrochelatase binding surface of human frataxin have been characterized to provide insight into the protein's ability to serve as the iron chaperone during heme biosynthesis.

Bencze, K.Z.; Yoon, T.; Millan-Pacheco, C.; Bradley, P.B.; Pastor, N.; Cowan, J.A.; Stemmler, T.L.

2009-06-02

381

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

Microsoft Academic Search

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

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

2008-01-01

382

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

383

Can an increase in leaf iron reductase activity enhance seed iron accumulation in soybean?  

Technology Transfer Automated Retrieval System (TEKTRAN)

Iron is an important micronutrient for human nutrition, with plant foods providing a significant amount of dietary iron in certain population groups, and in some cases, providing the sole source of dietary iron. Because iron deficiency is unfortunately common in many human populations, we have been...

384

Role of the Ferroportin Iron-Responsive Element in Iron and Nitric Oxide Dependent Gene Regulation  

Microsoft Academic Search

ABSTRACTThe newly described iron transporter, ferroportin (MTP1, IREG1), is expressed in a variety of tissues including the duodenum and cells of the mononuclear phagocyte system (MPS). In the MPS, ferroportin is hypothesized to be a major exporter of iron scavenged from senescent erythrocytes. Changes in iron metabolism, including the sequestration of iron in the MPS, are characteristic of both acute

Xiao-bing Liu; Ping Hill; David J. Haile

2002-01-01

385

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

386

Lost iron and iron converted into rust in steels submitted to dry–wet corrosion process  

Microsoft Academic Search

During the electrochemical corrosion of iron and steel not all the iron removed from the steel forms later part of the iron phases that remain stick to the surface. Here we report numerical data that demonstrates that the conversion of iron into adherent rust is not always equal to one, at least for steels submitted to chloride ions in dry–wet

K. E. García; C. A. Barrero; A. L. Morales; J. M. Greneche

2008-01-01

387

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

Microsoft Academic Search

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

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

388

The Contribution of Maternal Iron Stores to Fetal Iron in Rats  

Microsoft Academic Search

The contribution of maternal iron stores to fetal iron content in rats of the Sprague-Dawley strain has been examined. 59Fe was injected intramuscularly into two groups of rats to label iron in the liver. Two weeks later one group was bred. After delivery of fetuses, all animals were killed and examined for distribution of radioactivity and nonheme iron content in

M. J. MURRAY

389

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

390

Iron nutriture ine1der1y ia4ividuals  

Microsoft Academic Search

The purpose of this review is to examine current research on the iron status of the elderly and fac- tors that influence the body burden of iron. Studies of noninstitutionalized elderly individuals report mean iron intakes that meet current Recommended Dietary Al- lowances for iron. Dietary practicesthat may decrease iron bioavailability, and hence iron stores in the body, in- clude

G. FISCHER; A. BOWMAN; ELAINE W. GUNTER

391

Laboratorytests of iron status:correlation or common sense?  

Microsoft Academic Search

We demonstrate that simple correlation between the van- ous tests of iron status is not sufficient for examining their value in diagnosing iron deficiency (11)). Three degrees of ID are recognized: Iron depletion (ID grade I) is defined by decreased total body iron and normal iron support to erythropoiesis, as diagnosed by decreased storage iron, decreased ferritin, normal sideroblast count,

JAN HASTKA; JEAN-JACQUES LASSERRE; ANDREAS SCHWARZBECK; ANDREAS REITER; RUDIGER HEHLMANN

392

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

393

Diffusion of iron in gallium selenide  

SciTech Connect

The temperature dependence of the diffusion coefficient of iron in gallium selenide with a defective sphalerite lattice was studied in the range 98-450 C. Iron 55 and Iron 59, in the form of an iron chloride solution, were used as tracers. The activation energies of fast and slow diffusion in alpha-Ga/sub 2/Se/sub 3/ were determined to be, respectively, 25.1 and 21.2 kJ/mole.

Firsova, L.P.

1987-02-01

394

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

395

Effect of Iron Particle Size and Concentration on Thermal Conductivity of Iron/Polystyrene Composites  

NASA Astrophysics Data System (ADS)

The present study deals with the thermal conductivity of iron/polystyrene (PS) composites containing iron particles of different sizes: (5, 50, 150, and 250) \\upmu m, and with different iron concentrations: (0, 5, 10, 20 and 30) mass%. The effects of iron particle size and concentration on the thermal conductivity of iron/PS composites are investigated in the temperature range: (30 to 120)°C. It was found that the addition of ultrafine iron particles enhances the thermal conductivity of the composites more than that of larger (coarser) particles. The thermal conductivity also increases with increasing temperature and iron concentration. The glass transition temperature was found to increase with decreasing size of iron particles. A correlation between the observed electrical and thermal conductivities of the iron composites as a function of iron particle size is presented. Fitting of some theoretical models results in predictions of smaller values of the thermal conductivity than are the experimental values.

Elimat, Z. M.; AL-Aqrabawi, F. S.; Hazeem, T. Abu; Ramadin, Y.; Zihlif, A. M.

2013-08-01

396

Voice Modulations in German Ironic Speech  

ERIC Educational Resources Information Center

|Previous research has shown that in different languages ironic speech is acoustically modulated compared to literal speech, and these modulations are assumed to aid the listener in the comprehension process by acting as cues that mark utterances as ironic. The present study was conducted to identify paraverbal features of German "ironic

Scharrer, Lisa; Christmann, Ursula; Knoll, Monja

2011-01-01

397

Thermodynamic constraints on microbial iron oxide reduction  

Microsoft Academic Search

Iron oxides are ubiquitous reactive constituents of soils, sediments and aquifers. They exhibit large surface areas which bind trace metals, nutrients and organic molecules. Under suboxic conditions, iron oxides can reductively dissolve via several abiotic and microbial pathways. In particular, they serve as terminal electron acceptors for the oxidation of organic matter by iron reducing bacteria. The aim of our

S. Bonneville; T. Behrends; R. Haese; P. van Cappellen

2003-01-01

398

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

399

Applying of Aluminium Deoxidation in Iron Roll  

Microsoft Academic Search

In producing cast iron rolls for use in the hot rolling of billets, the furnace charge materials consist of bought in scrap, foundry returns and pig iron. Normally, to achieve acceptable casting quality, charges contain at least 30% pig iron. To meet increasingly tougher competition, foundries would like to reduce costs by using cheaper raw materials. To use greater proportions

Casting Teerapong Harnwirojkul; Mana Polboon; John Pearce; Thanaporn Korad

400

21 CFR 522.1182 - Iron injection.  

Code of Federal Regulations, 2013 CFR

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

2013-04-01

401

Intravenous iron sucrose: Establishing a safe dose  

Microsoft Academic Search

It is now recognized that the majority of patients on epoetin therapy require intravenous (IV) iron supplementation to maximize the response to treatment. Of the IV iron preparations available, iron sucrose has proved its efficacy and safety; however, there are no guidelines or systematic studies examining the optimum safe dosage regimen for this compound. The aim of the present study

Georgina Chandler; Jatinder Harchowal; Iain C. Macdougall

2001-01-01

402

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

403

In vivo iron metabolism by IRMS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Iron isotopes are used in both biological and geological investigations. Three low-abundance stable isotopes are available for human studies. They have been widely used to study iron metabolism. They have provided valuable insights into iron deficiency, one of the most common micronutrient deficienc...

404

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

405

Placental iron transfer in the cat  

PubMed Central

1. The transfer of iron from maternal plasma to the foetus was studied in the cat using cat transferrin labelled with 59Fe and radioiodine. 2. Pregnancy was accompanied by a fall in maternal haematocrit, a rise in serum total iron-binding capacity and iron stores, but no change in serum iron concentration or plasma iron turnover. 3. Near-term foetal haematocrit and serum iron concentration were higher and iron binding capacity lower than in the pregnant animals. 4. The uptake of 59Fe from maternal plasma by the placenta and transfer to the foetuses were slow and small in amount. The daily transfer of iron to the foetuses calculated from these data was only 5 ?g. 5. There was a small, transient uptake of 59Fe from the plasma by the foetal membranes. 6. Small amounts of plasma transferrin and albumin were slowly taken up by the placenta. 7. It was concluded that the maternal endothelium of the placenta of the cat acts as a barrier for the uptake of plasma transferrin-bound iron. As a result the rate of iron transfer to the foetuses from maternal plasma is inadequate to account for their rate of iron accumulation, and another source, such as maternal erythrocytes, must supply most of the iron to the foetuses.

Baker, Erica; Morgan, E. H.

1973-01-01

406

Rare causes of hereditary iron overload  

Microsoft Academic Search

Iron is a vitally important element in mammalian metabolism because of its unsurpassed versatility as a biologic catalyst. However, when not appropriately shielded or when present in excess, iron plays a key role in the formation of extremely toxic oxygen radicals, which ultimately cause peroxidative damage to vital cell structures. Organisms are equipped with specific proteins designed for iron acquisition,

Prem Ponka

2002-01-01

407

The Role of Iron in Neurocognitive Development  

Microsoft Academic Search

In this article we present a review of the current literature relating iron and iron deficiency to psychological and neurobiological outcomes in both humans and experimental animals. In particular, we focus on the role of iron during gestation and infancy and the possible impact on neurobehavioral development in the short and long term. In the context of reviewing this literature,

David G. Thomas; Stephanie L. Grant; Nicki L. Aubuchon-Endsley

2009-01-01

408

Iron and cadmium capture gamma-ray photofission measurements  

SciTech Connect

Photofission measurements have been made in {sup 238}U, {sup 232}Th, and {sup 237}Np in iron and cadmium capture gamma-ray spectra in cylindrical neutron-driven gamma-ray sources in the thermal column of the National Bureau of Standards (NBS) Reactor. The gamma-ray source strength was measured with neutron activation foils and by direct counting of activations produced in the metal cylinders. Photofission measurements were made with NBS miniature fission chambers. The integral photofission cross sections were compared with differential measurements by integrating the capture gamma-ray spectra with measured cross-section shapes. The integral cross sections measured in the capture gamma-ray fields are lower than the cross sections calculated from measured differential data.

Williamson, T.G. (Virginia Univ., Charlottesville, VA (USA). Dept. of Nuclear Engineering); Lamaze, G.P.; Gilliam, D.M.; Eisenhauer, C.M. (National Inst. of Standards and Technology, Gaithersburg, MD (USA))

1990-01-01

409

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

410

Homeostatic Regulation of Iron and Its Role in Normal and Abnormal Iron Status in Infancy and Childhood  

Microsoft Academic Search

Iron is important in neurodevelopment and cognitive function, and globally preventing iron deficiency and iron deficiency anemia remains a high priority. Term breast-fed infants and infants fed an iron-fortified formula usually have a satisfactory iron status during the first 6 months of life, but there are still ambiguities in assessing iron status in infants and how to properly meet their

Bo Lönnerdal; Olle Hernell

2010-01-01

411

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

412

TRITIUM MEASUREMENTS ON IRON METEORITES  

Microsoft Academic Search

The tritium content of seven iron meteorites, five chondrites and two ; achondrites, was determined by the usual method of fusion of the sampie in high ; vacumm and pumping the hydrogen obtained into a counter tube. The values ; obtained are tabulated and show that the ratio of the number of T decays per ; minute and gram to

K. Goebel; P. Schmidlin

1960-01-01

413

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,...

414

Iron Pyrites.Curious Phenomenon  

Microsoft Academic Search

SOME iron pyrites exhibited in a particular case in the Maidstone Museum have crumbled into a coarse, finely-divided mass. The specimens have been exhibited for about two months, and the decomposition has been effected in that time. Some other specimens recently removed from another case are becoming soft.

Frederic Case

1875-01-01

415

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

416

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

417

FUGITIVE EMISSIONS FROM IRON FOUNDRIES  

EPA Science Inventory

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

418

Iron catalyzed coal liquefaction process  

Microsoft Academic Search

A process is described for the solvent refining of coal into a gas product, a liquid product and a normally solid product. Particulate coal and a unique co-catalyst system are suspended in a coal solvent and processed in a coal liquefaction reactor, preferably an ebullated bed reactor. The co-catalyst system comprises a combination of a stoichiometric excess of iron oxide

D. Garg; E. N. Givens

1983-01-01

419

Iron catalyzed coal liquefaction process  

Microsoft Academic Search

A process is described for the solvent refining of coal into a gas product, a liquid product and a normally solid dissolved product. Particulate coal and a unique co-catalyst system are suspended in a coal solvent and processed in a coal liquefaction reactor, preferably an ebullated bed reactor. The co-catalyst system comprises a combination of a stoichiometric excess of iron

Diwakar Garg; Edwin N. Givens

1983-01-01

420

Corrosion of ductile iron piping  

SciTech Connect

A compilation of 20 classic NACE papers on the subject, dating from 1957 to 1994. Papers include: Corrosion of Municipal Iron Watermains, Protecting Water Pipelines with Pipeline Coatings Conforming to American Water Works Association Coating Standards, Analysis of Aged Water Distribution Systems, and many more.

Szeliga, M. [ed.

1995-12-31

421

Wear resistance of ductile irons  

SciTech Connect

This study was undertaken to evaluate the wear resistance of different grades of ductile iron as alternatives to high-tensile-strength alloyed and inoculated gray irons and bronzes for machine-tool and high-pressure hydraulic components. Special test methods were employed to simulate typical conditions of reciprocating sliding wear with and without abrasive-contaminated lubricant for machine and press guideways. Quantitative relationships were established among wear rate, microstructure and microhardness of structural constituents, and nodule size of ductile iron. The frictional wear resistance of ductile iron as a bearing material was tested with hardened steel shafts using standard test techniques under continuous rotating movement with lubricant. Lubricant sliding wear tests on specimens and components for hydraulic equipment and apparatus were carried out on a special rig with reciprocating motion, simulating the working conditions in a piston/cylindrical unit in a pressure range from 5 to 32 MPa. Rig and field tests on machine-tool components and units and on hydraulic parts have confirmed the test data.

Lerner, Y.S. (Grede Foundries, Inc., Cynthiana, KY (United States))

1994-06-01

422

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

423

Iron transportation across the placenta.  

PubMed

According to the classification of placental types among animals, the transfer of iron through the placenta can occur via: absorption connected to transferin through the outer surface of the trophoblast in direct contact with circulating maternal blood; absorption of the erythrocytes by the chorionic epithelium in direct contact with accumulation of blood extravased from haemotophagous areas; absorption by the chorionic epithelium in direct contact with iron enriched secretions from the endometrial glands and absorption by extravasations of the blood in the maternal-fetal surface and the subsequent phagocytosis of the erythrocytes by trophoblast cells described in bovine, small ruminants, canine and feline. The function of erythrophagocytosis observed after the extravasation of blood in the maternal-fetal interface is undefined in several species. Possibly, the iron is transferred to the fetus through the trophoblastic erythrophagocytosis in the hemophogous area of the placenta and also in the endometrial glands. In this literature survey, new methods of studies regarding placental transfer involving iron and other nutrients necessary for survival and maintenance of embryonic fetus to birth are proposed. PMID:22935921

Oliveira, Claudia M de; Rodrigues, Marcio N; Miglino, Maria Angélica

2012-08-30

424

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

EPA Science Inventory

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

425

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

EPA Science Inventory

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

426

Experimental Confirmation of the X-Ray Magnetic Circular Dichroism Sum Rules for Iron and Cobalt  

Microsoft Academic Search

High precision, L2,3-edge photoabsorption and magnetic circular dichroism spectra of iron and cobalt were measured in transmission with in situ grown thin films, eliminating experimental artifacts encountered by the indirect methods used in all previous measurements. The magnetic moments determined from the integrals of these spectra are found to be in excellent agreement (within 3%) for the orbital to spin

C. T. Chen; Y. U. Idzerda; H.-J. Lin; N. V. Smith; G. Meigs; E. Chaban; G. H. Ho; E. Pellegrin; F. Sette

1995-01-01

427

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

EPA Science Inventory

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

428

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

ERIC Educational Resources Information Center

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

Whitman, Maryann

429

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...

430

Influence of surfactants on filter cake parameters during vacuum filtration of flocculated iron ore sludge  

Microsoft Academic Search

The influence of certain surfactants on the dewatering of fine iron ore sludge flocculated with anionic flocculants has been investigated in a laboratory-scale vacuum filtration unit. The filtration data have been used in calculating the cake parameters from an integrated form of Darcy's law. A narrow concentration range of surfactant enables reduction of the specific cake resistance and an enhanced

L. Besra; B. P. Singh; P. S. R. Reddy; D. K. Sengupta

1998-01-01

431

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

ERIC Educational Resources Information Center

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

Whitman, Maryann

432

Global survey of Fur binding refines the iron responsive regulon of Pseudomonas syringae  

Technology Transfer Automated Retrieval System (TEKTRAN)

Pseudomonas syringae must sense and respond to a variety of environmental signals and understanding how the bacterium integrates these signals into a physiological response is central to our understanding of this plant pathogen. One important micronutrient for all biological organisms is iron. Pre...

433

Integrated Networks.  

ERIC Educational Resources Information Center

|A strategy for integrated data and voice networks implemented at the University of Michigan is described. These networks often use multi-technologies, multi-vendors, and multi-transmission media that will be fused into a single integrated network. Transmission media include twisted-pair wire, coaxial cable, fiber optics, and microwave.…

Robinovitz, Stewart

1987-01-01

434

Formation of IIAB iron meteorites  

NASA Astrophysics Data System (ADS)

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

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

2007-02-01

435

Validation of Gamma-Ray Production Data of Iron in JENDL-3.2 with Shielding Benchmark  

Microsoft Academic Search

An integral test of ?-ray production data of iron in the latest version of Japanese Evaluated Nuclear Data Library (JENDL-3.2) has been performed by means of a shielding benchmark analysis of KfK leakage neutron and ?-ray spectrum measurements from iron spheres with a Cf source in the center. Two comprehensive systems which consist of a continuous-energy Monte Carlo method and

Naoki YAMANO; Kohtaro UEKI

1995-01-01

436

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

437

[Treatment of disorders of iron metabolism].  

PubMed

When prescribing oral iron preparations, consideration must be given in particular to the question of bioavailability. In this connection, ferrous sulfate preparations are to be preferred. The simultaneous ingestion of tea, coffee or dairy products reduces the absorption of iron, while ascorbic acid increases it. Gastrointestinal side effects of oral iron substitution are usually dose-dependent. If absorption or mobilization disorders, gastrointestinal diseases or signs of intolerance to oral administration are present, iron must be administered via the parenteral route. To avoid toxicity, accurate calculation of the dose is necessary before injection. Since intolerance reactions extending to anaphylactic shock can occur, the indication for iron preparations must be rigorously applied. PMID:15625935

Pinggera, Wulf

2004-11-25

438

Metabolic Remodeling in Iron-deficient Fungi  

PubMed Central

Eukaryotic cells contain dozens, perhaps hundreds, of iron-dependent proteins, which perform critical functions in nearly every major cellular process. Nutritional iron is frequently available to cells in only limited amounts; thus, unicellular and higher eukaryotes have evolved mechanisms to cope with iron scarcity. These mechanisms have been studied at the molecular level in the model eukaryotes Saccharomyces cerevisiae and Schizosaccharomyces pombe, as well as in some pathogenic fungi. Each of these fungal species exhibits metabolic adaptations to iron deficiency that serve to reduce the cell’s reliance on iron. However, the regulatory mechanisms that accomplish these adaptations differ greatly between fungal species.

Philpott, Caroline C.; Leidgens, Sebastien; Frey, Avery G.

2012-01-01

439

THE INFLUENCE OF DIET ON IRON ABSORPTION  

PubMed Central

Rats placed on a corn grit diet and added iron absorbed large amounts of iron in contrast to control groups. The histological picture was that of progressive hemosiderosis of the hepatic parenchyma and of the reticuloendothelial system. On chemical analysis, the iron content of the liver was found to be greatly increased. This supports the concept that the liver represents the chief storage organ for iron so absorbed. These data indicate that a normal block for iron absorption may be overcome under certain circumstances.

Kinney, Thomas D.; Hegsted, D. Mark; Finch, Clement A.

1949-01-01

440

Weekly low-dose treatment with intravenous iron sucrose maintains iron status and decreases epoetin requirement in iron-replete haemodialysis patients  

Microsoft Academic Search

Background. Haemodialysis patients need sustained treatment with intravenous iron because iron defi- ciency limits the efficacy of recombinant human epoetin therapy in these patients. However, the optimal intravenous iron maintenance dose has not been established yet. Methods. We performed a prospective multicentre clinical trial in iron-replete haemodialysis patients to evaluate the efficacy of weekly low-dose (50 mg) intravenous iron sucrose

Daniela Schiesser; Isabelle Binet; Dimitrios Tsinalis; Michael Dickenmann; Markus Schmidli; Patrice M. Ambuhl; Rudolf P. Wuthrich

441

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

442

Iron acquisition by Legionella pneumophila.  

PubMed

For nearly 20 years, it was believed that Legionella pneumophila does not produce siderophores. Yet, we have now determined that L. pneumophila secretes a siderophore (legiobactin) that is detectable by the CAS assay. We have optimized conditions for legiobactin expression, shown its biological activity, and found genes (lbtAB) involved in its production and secretion. LbtA is homologous with siderophore synthetases from E. coli (aerobactin), Sinorhizobium (rhizobactin), and Bordetella (alcaligin), while LbtB is a member of the major facilitator superfamily of multidrug efflux pumps. Mutants lacking lbtAB produce 40-70% less CAS reactivity. The lbtA mutant is also defective for growth in deferrated media containing citrate, indicating that legiobactin is required in conditions of severe iron limitation. lbtAB mutants grow normally in macrophages and amoebae host cells as well as within the lungs of mice. L. pneumophila does express lbtA in macrophages, suggesting that legiobactin has a dispensable role in infection. Legiobactin is iron repressed and does not react in the Csáky and Arnow assays. Anion-exchange HPLC has been used to purify legiobactin, and thus far, structural analysis suggests that the molecule is similar but not identical to rhizobactin, rhizoferrin, and alcaligin. The residual CAS reactivity present in supernatants of the lbtAB mutants suggests that L. pneumophila might produce a second siderophore. Besides siderophores, we have determined that ferrous iron transport, encoded by feoB, is critical for L. pneumophila growth in low-iron conditions, in host cells, and in the mammalian lung. Some of our other studies have discovered a critical, yet undefined, role for the L. pneumophila cytochrome c maturation locus in low-iron growth, intracellular infection, and virulence. PMID:17180462

Cianciotto, Nicholas P

2006-12-16

443

Proteomic analysis of iron acquisition, metabolic and regulatory responses of Yersinia pestis to iron starvation  

PubMed Central

Background The Gram-negative bacterium Yersinia pestis is the causative agent of the bubonic plague. Efficient iron acquisition systems are critical to the ability of Y. pestis to infect, spread and grow in mammalian hosts, because iron is sequestered and is considered part of the innate host immune defence against invading pathogens. We used a proteomic approach to determine expression changes of iron uptake systems and intracellular consequences of iron deficiency in the Y. pestis strain KIM6+ at two physiologically relevant temperatures (26°C and 37°C). Results Differential protein display was performed for three Y. pestis subcellular fractions. Five characterized Y. pestis iron/siderophore acquisition systems (Ybt, Yfe, Yfu, Yiu and Hmu) and a putative iron/chelate outer membrane receptor (Y0850) were increased in abundance in iron-starved cells. The iron-sulfur (Fe-S) cluster assembly system Suf, adapted to oxidative stress and iron starvation in E. coli, was also more abundant, suggesting functional activity of Suf in Y. pestis under iron-limiting conditions. Metabolic and reactive oxygen-deactivating enzymes dependent on Fe-S clusters or other iron cofactors were decreased in abundance in iron-depleted cells. This data was consistent with lower activities of aconitase and catalase in iron-starved vs. iron-rich cells. In contrast, pyruvate oxidase B which metabolizes pyruvate via electron transfer to ubiquinone-8 for direct utilization in the respiratory chain was strongly increased in abundance and activity in iron-depleted cells. Conclusions Many protein abundance differences were indicative of the important regulatory role of the ferric uptake regulator Fur. Iron deficiency seems to result in a coordinated shift from iron-utilizing to iron-independent biochemical pathways in the cytoplasm of Y. pestis. With growth temperature as an additional variable in proteomic comparisons of the Y. pestis fractions (26°C and 37°C), there was little evidence for temperature-specific adaptation processes to iron starvation.

2010-01-01

444

Iron redistribution as a therapeutic strategy for treating diseases of localized iron accumulation.  

PubMed

Defective iron utilization leading to either systemic or regional misdistribution of the metal has been identified as a critical feature of several different disorders. Iron concentrations can rise to toxic levels in mitochondria of excitable cells, often leaving the cytosol iron-depleted, in some forms of neurodegeneration with brain accumulation (NBIA) or following mutations in genes associated with mitochondrial functions, such as ABCB7 in X-linked sideroblastic anemia with ataxia (XLSA/A) or the genes encoding frataxin in Friedreich's ataxia (FRDA). In anemia of chronic disease (ACD), iron is withheld by macrophages, while iron levels in extracellular fluids (e.g., plasma) are drastically reduced. One possible therapeutic approach to these diseases is iron chelation, which is known to effectively reduce multiorgan iron deposition in iron-overloaded patients. However, iron chelation is probably inappropriate for disorders associated with misdistribution of iron within selected tissues or cells. One chelator in clinical use for treating iron overload, deferiprone (DFP), has been identified as a reversed siderophore, that is, an agent with iron-relocating abilities in settings of regional iron accumulation. DFP was applied to a cell model of FRDA, a paradigm of a disorder etiologically associated with cellular iron misdistribution. The treatment reduced the mitochondrial levels of labile iron pools (LIP) that were increased by frataxin deficiency. DFP also conferred upon cells protection against oxidative damage and concomitantly mediated the restoration of various metabolic parameters, including aconitase activity. Administration of DFP to FRDA patients for 6 months resulted in selective and significant reduction in foci of brain iron accumulation (assessed by T2* MRI) and initial functional improvements, with only minor changes in net body iron stores. The prospects of drug-mediated iron relocation versus those of chelation are discussed in relation to other disorders involving iron misdistribution, such as ACD and XLSA/A. PMID:20393584

Kakhlon, Or; Breuer, William; Munnich, Arnold; Cabantchik, Z Ioav

2010-03-01

445

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

446

Adipocyte iron regulates adiponectin and insulin sensitivity.  

PubMed

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. PMID:22996660

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

2012-09-10

447

Vacancy coalescence during oxidation of iron nanoparticles  

SciTech Connect

In the present work, we analyze the geometry and composition of the nanostructures obtained from the oxidation of iron nanoparticles. The initial oxidation of iron takes place by outward diffusion of cations through the growing oxide shell. This net material flow is balanced by an opposite flow of vacancies, which coalesce at the metal/oxide interface. Thus, the partial oxidation of colloidal iron nanoparticles leads to the formation of core-void-shell nanostructures. Furthermore, the complete oxidation of iron nanoparticles in the 3-8 nm size range leads to the formation of hollow iron oxide nanoparticles. We analyze the size and temperature range in which vacancy coalescence during oxidation of amine-stabilized iron nanoparticles takes place. Maghemite is the crystallographic structure obtained from the complete oxidation of iron nanoparticles under our synthetic conditions.

Cabot, Andreu; Puntes, Victor F.; Shevchenko, Elena; Yin, Yadong; Balcells, Lluis; Markus, Matthew A.; Hughes, Steven M.; Alivisatos, A. Paul

2007-06-14

448

Iron regulatory proteins control a mucosal block to intestinal iron absorption.  

PubMed

Mammalian iron metabolism is regulated systemically by the hormone hepcidin and cellularly by iron regulatory proteins (IRPs) that orchestrate a posttranscriptional regulatory network. Through ligand-inducible genetic ablation of both IRPs in the gut epithelium of adult mice, we demonstrate that IRP deficiency impairs iron absorption and promotes mucosal iron retention via a ferritin-mediated "mucosal block." We show that IRP deficiency does not interfere with intestinal sensing of body iron loading and erythropoietic iron need, but rather alters the basal expression of the iron-absorption machinery. IRPs thus secure sufficient iron transport across absorptive enterocytes by restricting the ferritin "mucosal block" and define a basal set point for iron absorption upon which IRP-independent systemic regulatory inputs are overlaid. PMID:23523353

Galy, Bruno; Ferring-Appel, Dunja; Becker, Christiane; Gretz, Norbert; Gröne, Hermann-Josef; Schümann, Klaus; Hentze, Matthias W

2013-03-21

449

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

2011-12-09

450

Photosynthetic maximum quantum yield increases are an essential component of the Southern Ocean phytoplankton response to iron  

PubMed Central

It is well established that an increase in iron supply causes an increase in total oceanic primary production in many regions, but the physiological mechanism driving the observed increases has not been clearly identified. The Southern Ocean iron enrichment experiment, an iron fertilization experiment in the waters closest to Antarctica, resulted in a 9-fold increase in chlorophyll (Chl) concentration and a 5-fold increase in integrated primary production. Upon iron addition, the maximum quantum yield of photosynthesis (?m) rapidly doubled, from 0.011 to 0.025 mol C·mol quanta?1. Paradoxically, this increase in light-limited productivity was not accompanied by a significant increase in light-saturated productivity (Pmaxb). Pmaxb, maximum Chl normalized productivity, was 1.34 mg C·mg Chl?1·h?1 outside and 1.49 mg C·mg Chl?1·h?1 inside the iron-enriched patch. The importance of ?m as compared with Pmaxb in controlling the biological response to iron addition has vast implications for understanding the ecological response to iron. We show that an iron-driven increase in ?m is the proximate physiological mechanism affected by iron addition and can account for most of the increases in primary production. The relative importance of ?m over Pmaxb in this iron-fertilized bloom highlights the limitations of often-used primary productivity algorithms that are driven by estimates of Pmaxb but largely ignore variability in ?m and light-limited productivity. To use primary productivity models that include variability in iron supply in prediction or forecasting, the variability of light-limited productivity must be resolved.

Hiscock, Michael R.; Lance, Veronica P.; Apprill, Amy M.; Bidigare, Robert R.; Johnson, Zackary I.; Mitchell, B. Greg; Smith, Walker O.; Barber, Richard T.

2008-01-01

451

Side effects of iron supplements in blood donors: superior tolerance of heme iron.  

PubMed

Regular blood donors were enrolled in a double-blind, parallel group study to evaluate the side effects of two iron supplements, one containing both heme iron and non-heme iron (Hemofer, 2 tablets = 18 mg iron/day), the other non-heme iron only (Erco-Fer; 1 tablet = 60 mg iron/day). No differences were found between the two alternatives in regaining predonation iron status as measured by serum ferritin and hemoglobin levels. Despite this therapeutic equivalence, participants' symptom diaries showed substantial differences in the side effects for the two treatments. The frequency of constipation (p < 0.05) and the total incidence of all side effects (p < 0.01) were significantly higher for non-heme iron when compared with the heme iron-non-heme iron combination and a placebo. The study demonstrates that a low-dose iron supplement containing both heme iron and non-heme iron (Hemofer) has fewer side effects when compared with an equipotent, traditional non-heme iron supplement. PMID:8145004

Frykman, E; Bystrom, M; Jansson, U; Edberg, A; Hansen, T

1994-04-01

452

The Iron Project: Atomic Data for the Iron Peak Elements  

NASA Astrophysics Data System (ADS)

Emission and absorption lines from Iron ions are of great importance as diagnostics for a large variety of objects and in most wavelength ranges, from the X-ray and extreme UV up to the far IR. The IRON Project is an international collaboration devoted to the study of atomic processes and the calculation of collisional and radiative data for ions of the iron-peak elements for applications in astrophysical and laboratory plasmas. The ab initio atomic calculations are carried out in the close-coupling approximation, using the R-matrix method and a package of codes developed for the Opacity Project and extended to include relativistic effects in the Breit-Pauli approximation. Parameters for many of the atomic processes of importance in astrophysics are calculated: (i) photoionization cross sections, (ii) total e-ion recombination rates including both the radiative and di-electr onic recombination processes, (iii) collision strengths, and (iv) radiative transition probabilities. Selected results will be presented for Fe I, Fe II, Fe III, Fe IV, Fe V, Fe XXII, Fe XXV, and Ni II. Of particular interest are the results for the low ionization stages of Iron: Fe I,II, and III, for which the new photoionization cross sections and corresponding recombination rates, both computed in a self-consistent manner for the first time, differ from the data currently in use in astrophysical models by up to several orders of magnitude. Also, at Ohio State, a parallelized version of the R-matrix codes has been developed for the massively parallel machine Cray T3D, thus enhancing the computational capabilities needed for such extensive calculations. The work is supported partially by the U.S. National Science Foundation (PHY-9421898), the NASA LTSA program (NAGW-3315) and the NASA ADP program (NAS5-32643).

Pradhan, A. K.; Zhang, H. L.; Nahar, S. N.; Bautista, M. A.

1996-05-01

453

Iron Uptake and Release by Macrophages is Sensitive to Propranolol  

Microsoft Academic Search

In this study we have tested the effects of d-propranolol (D-Pro) on the iron uptake, iron release and oxidative response of iron-loaded cells in a cellular model of iron-overload using isolated rat peritoneal macrophages incubated with iron-dextran (Fe-D). Pretreatment of macrophages with D-Pro (5–200 ? M) prior to Fe-D exposure decreased the cellular iron content and partially prevented iron release

Andrei M. Komarov; Jonathon M. Hall; Joanna J. Chmielinska; William B. Weglicki

2006-01-01

454

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

455

Dietary fat level affects tissue iron levels but not the iron regulatory gene HAMP in rats.  

PubMed

Because dietary fats affect the regulation and use of body iron, we hypothesized that iron regulatory and transport genes may be affected by dietary fat. A model of early-stage I to II, nonalcoholic fatty liver was used in which rats were fed standard (35% energy from fat) or high-fat (71% energy from fat) liquid diets with normal iron content (STD/HF groups). In addition, intraperitoneal injections of iron dextran were given to iron-loaded (STD+/HF+ groups) and iron-deficient diets to STD-/HF- groups. Plasma osmolality, hemoglobin level, and mean corpuscular hemoglobin concentration were increased in all STD diet groups compared with all HF diet groups. Plasma iron and transferrin saturation were affected by an interaction between dietary fat and iron. They were high in the STD group (normal iron) compared with their respective HF group. Similarly, this group also showed a 4-fold increase in the messenger RNA expression of the hepatic hemochromatosis gene. Spleen iron was high in the iron-loaded STD+ group compared with all other groups. Hepatic iron and messenger RNA expression of peroxisome proliferator-activated receptor-?, CCAAT/enhancer binding protein ?, interleukin-6, and iron transport genes (transferrin receptor 2, divalent metal transporter 1 iron-responsive element, and divalent metal transporter 1 non-iron-responsive element) were increased, whereas tumor necrosis factor ? was decreased in the HF diet groups. The expression of iron regulatory gene HAMP was not increased in the HF diet groups. Iron regulatory and transport genes involved in cellular and systemic iron homeostasis may be affected by the macronutrient composition of the diet. PMID:23399663

Ahmed, Umbreen; Oates, Phillip S

2012-12-20

456

[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