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Sample records for ferrous bisglycinate chelate

  1. Effect of supplementation with ferrous sulfate or iron bis-glycinate chelate on ferritin concentration in Mexican schoolchildren: a randomized controlled trial

    PubMed Central

    2014-01-01

    Background Iron deficiency is one of the most common nutritional deficiencies worldwide. It is more prevalent when iron requirements are increased during pregnancy and during growth spurts of infancy and adolescence. The last stage in the process of iron depletion is characterized by a decrease in hemoglobin concentration, resulting in iron deficiency anemia. Iron deficiency, even before it is clinically identified as anemia, compromises the immune response, physical capacity for work, and intellectual functions such as attention level. Therefore, interventions addressing iron deficiency should be based on prevention rather than on treatment of anemia. The aim of this study was to compare short- and medium-term effects on ferritin concentration of daily supplementation with ferrous sulfate or iron bis-glycinate chelate in schoolchildren with iron deficiency but without anemia. Methods Two hundred schoolchildren from public boarding schools in Mexico City who had low iron stores as assessed by serum ferritin concentration but without anemia were randomly assigned to a daily supplement of 30 mg/day of elemental iron as ferrous sulfate or iron bis-glycinate chelate for 12 weeks. Iron status was evaluated at baseline, one week post-supplementation (short term), and 6 months (medium term) after supplementation. Results Ferritin concentration increased significantly between baseline and post-supplementation as well as between baseline and 6 months after supplementation. One week post-supplementation no difference was found in ferritin concentration between iron compounds, but 6 months after supplementation ferritin concentration was higher in the group that received bis-glycinate chelate iron. However, there is no difference in the odds for low iron storage between 6 months after supplementation versus the odds after supplementation; nor were these odds different by type of supplement. Hemoglobin concentration did not change significantly in either group after supplementation. Conclusions Supplementing with 30 mg/d of elementary iron, either as ferrous sulfate or iron bis-glycinate chelate for 90 days, showed positive effects on increasing ferritin concentration in schoolchildren with low iron stores, and this effect persisted 6 months after supplementation. PMID:25023784

  2. Study of Anti-Fatigue Effect in Rats of Ferrous Chelates Including Hairtail Protein Hydrolysates.

    PubMed

    Huang, Saibo; Lin, Huimin; Deng, Shang-Gui

    2015-01-01

    The ability of ferrous chelates including hairtail protein hydrolysates to prevent and reduce fatigue was studied in rats. After hydrolysis of hairtail surimi with papain, the hairtail protein hydrolysates (HPH) were separated into three groups by range of relative molecular weight using ultrafiltration membrane separation. Hairtail proteins were then chelated with ferrous ions, and the antioxidant activity, the amino acid composition and chelation rate of the three kinds of ferrous chelates including hairtail protein hydrolysates (Fe-HPH) were determined. Among the three groups, the Fe-HPH chelate showing the best conditions was selected for the anti-fatigue animal experiment. For it, experimental rats were randomly divided into seven groups. Group A was designated as the negative control group given distilled water. Group B, the positive control group, was given glutathione. Groups C, D and E were designated as the Fe-HPH chelate treatment groups and given low, medium, and high doses, respectively. Group F was designated as HPH hydrolysate treatment group, and Group G was designated as FeCl? treatment group. The different diets were orally administered to rats for 20 days. After that time, rats were subjected to forced swimming training after 1 h of gavage. Rats given Fe-FPH chelate had higher haemoglobin regeneration efficiency (HRE), longer exhaustive swimming time and higher SOD activity. Additionally, Fe-FPH chelate was found to significantly decrease the malondialdehyde content, visibly enhance the GSH-Px activity in liver and reduce blood lactic acid of rats. Fe-HPH chelate revealed an anti-fatigue effect, similar to or better than the positive control substance and superior to HPH or Fe when provided alone. PMID:26633476

  3. Study of Anti-Fatigue Effect in Rats of Ferrous Chelates Including Hairtail Protein Hydrolysates

    PubMed Central

    Huang, Saibo; Lin, Huimin; Deng, Shang-gui

    2015-01-01

    The ability of ferrous chelates including hairtail protein hydrolysates to prevent and reduce fatigue was studied in rats. After hydrolysis of hairtail surimi with papain, the hairtail protein hydrolysates (HPH) were separated into three groups by range of relative molecular weight using ultrafiltration membrane separation. Hairtail proteins were then chelated with ferrous ions, and the antioxidant activity, the amino acid composition and chelation rate of the three kinds of ferrous chelates including hairtail protein hydrolysates (Fe-HPH) were determined. Among the three groups, the Fe-HPH chelate showing the best conditions was selected for the anti-fatigue animal experiment. For it, experimental rats were randomly divided into seven groups. Group A was designated as the negative control group given distilled water. Group B, the positive control group, was given glutathione. Groups C, D and E were designated as the Fe-HPH chelate treatment groups and given low, medium, and high doses, respectively. Group F was designated as HPH hydrolysate treatment group, and Group G was designated as FeCl2 treatment group. The different diets were orally administered to rats for 20 days. After that time, rats were subjected to forced swimming training after 1 h of gavage. Rats given Fe-FPH chelate had higher haemoglobin regeneration efficiency (HRE), longer exhaustive swimming time and higher SOD activity. Additionally, Fe-FPH chelate was found to significantly decrease the malondialdehyde content, visibly enhance the GSH-Px activity in liver and reduce blood lactic acid of rats. Fe-HPH chelate revealed an anti-fatigue effect, similar to or better than the positive control substance and superior to HPH or Fe when provided alone. PMID:26633476

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

    PubMed

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

    2015-03-18

    The ferrous (Fe2+) chelating capabilities of WPI hydrolysate fractions produced via cascade membrane filtration were investigated, specifically 1 kDa permeate (P) and 30 kDa retentate (R) fractions. The 1 kDa-P possessed a Fe2+ chelating capability at 1 g L(-1) equivalent to 84.4 μM EDTA (for 30 kDa-R the value was 8.7 μM EDTA). Fourier transformed infrared (FTIR) spectroscopy was utilized to investigate the structural characteristics of hydrolysates and molecular interactions with Fe2+. Solid-phase extraction was employed to enrich for chelating activity; the most potent chelating fraction was enriched in histidine and lysine. The solubility of ferrous sulfate solutions (10 mM) over a range of pH values was significantly (P<0.05) improved in dispersions of hydrolysate fraction solutions (10 g protein L(-1)). Total iron solubility was improved by 72% in the presence of the 1 kDa-P fraction following simulated gastrointestinal digestion (SGID) compared to control FeSO4·7H2O solutions. PMID:25716093

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

    NASA Astrophysics Data System (ADS)

    Mondal, P.; Sleep, B.

    2014-12-01

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

  6. Combined NO/sub x//SO/sub 2/ removal from flue gas using ferrous chelates of SH-containing amino acids and alkali

    SciTech Connect

    Liu, D.K.; Chang, S.G.

    1987-04-01

    We report herein the use of ferrous chelates of SH-containing amino acids including cysteine, penicillamine, N-acetylcysteine, and N-acetylpenicillamine in neutral or alkaline solutions for the combined removal of NO and SO/sub 2/ in wet flue gas clean-up systems. These SH-containing amino acids not only can stabilize ferrous ions in alkaline solutions to promote the absorption of NO, but are also capable of rapidly reducing ferric ions formed during the scrubbing process back to ferrous ions. The disulfide form of the above amino acids can be reduced by SO/sub 2/ and H/sub 2/S to regenerate the starting monomeric species. The chemistry relevant to the absorption of NO by the above ferrous chelates and the ligand regeneration process will be discussed.

  7. Combined NO/sub x//SO/sub 2/ removal from flue gas using ferrous chelates of SH-containing amino acids and alkali

    SciTech Connect

    Liu, D.K.; Chang, S.G.

    1987-01-01

    We report herein the use of ferrous chelates of SH-containing amino acids including cysteine, penicillamine, N-acetylcysteine, and N-acetylpenicillamine in neutral or alkaline solutions for the combined removal of NO and SO/sub 2/ in wet flue gas clean-up systems. These SH-containing amino acids not only can stabilize ferrous ions in alkaline solutions to promote the absorption of NO, but are also capable of rapidly reducing ferric ions formed during the scrubbing process back to ferrous ions. The disulfide from of the above amino acids can be reduced by SO/sub 2/ and H/sub 2/S to regenerate the starting monomeric species. The chemistry relevant to the absorption of NO by the above ferrous chelates and the ligand regeneration process will be discussed.

  8. Toxicological evaluation of ferrous N-carbamylglycinate chelate: Acute, Sub-acute toxicity and mutagenicity.

    PubMed

    Wan, Dan; Zhou, Xihong; Xie, Chunyan; Shu, Xugang; Wu, Xin; Yin, Yulong

    2015-11-01

    Iron is an essential trace element that is vital important in various biological process. A deficiency in iron could induce public health problem e.g. anaemia, while an overload could induce ROS production, lipid peroxidation and DNA bases modifications. In the present study, a new iron fortifier was synthesized, and its acute/sub-acute toxicity was investigated. According to the improved Karber's method, the median lethal dose (LD50) of the ferrous N-carbamylglycinate in SD rat was 3.02 g/kg and the 95% confidence intervals were between 2.78 and 3.31 g/kg. No biologically significant or test substance-related differences were observed in body weights, feed consumption, clinical signs, organ weights, histopathology, ophthalmology, hematology, and clinical chemistry parameters in any of the treatment groups of ferrous N-carbamylglycinate at target concentrations corresponding to 150, 300, and 600 mg/kg/day for 28 days. The no observed adverse effect level (NOAEL) for ferrous N-carbamylglycinate was at least 600 mg/kg b.w. day in rats. In addition, no evidence of mutagenicity was found, either in vitro in bacterial reverse mutation assay or in vivo in mice bone marrow micronucleus assay and sperm shape abnormality assay. On the basis of our findings, we conclude that ferrous N-carbamylglycinate is a low-toxic substance with no genotoxicity. PMID:26364753

  9. Use of ferrous chelates of SH-containing amino acids and peptides for the removal of NO/sub x/ and SO/sub 2/ from flue gas

    SciTech Connect

    Chang, S.G.; Littlejohn, D.; Liu, D.K.

    1988-11-01

    The use of ferrous complexes of SH-containing amino acids and peptides for the removal of NO and SO/sub 2/ in wet flue gas clean-up systems is reported. The ferrous chelates investigated in the present study include those of cysteine, N-acetylcysteine, penicillamine, N-acetylpenicillamine, glutathine, and cysteinylglycine. Compared to conventional chelates such as EDTA, these thioamino acids/peptides not only can stabilize ferrous ion in alkaline solutions to promote the absorption of NO but are also capable of rapidly reducing any ferric ions formed during the scrubbing process back to ferrous ions so that continual absorption of NO can be achieved. In the case of ferrous cysteine and ferrous penicillamine, most of the absorbed NO is reduced to N/sub 2/. The disulfide form of several of the thioamino acids/peptides produced upon oxidation can be conveniently reduced by SO/sub 2/ and H/sub 2/S to regenerate the starting materials, thus making possible the recycling of the reagents.

  10. Mssbauer Spectroscopy of Iron Containing Vitamins and Dietary Supplements

    NASA Astrophysics Data System (ADS)

    Oshtrakh, M. I.; Milder, O. B.; Semionkin, V. A.

    2004-12-01

    Mssbauer spectroscopy was used to study various industrial samples of vitamins containing ferrous fumarate and ferrous bisglycinate chelate (Ferrochel) and dietary supplements containing ferrous sulfate. The presence of small quantities of various ferric impurities was found. Two vitamins contained major iron compounds that did not correspond to ferrous fumarate and ferrous bisglycinate chelate.

  11. Deoxyribonucleic acid-protein and deoxyribonucleic acid interstrand cross-links induced in isolated chromatin by hydrogen peroxide and ferrous ethylenediaminetetraacetate chelates

    SciTech Connect

    Lesko, S.A.; Drocourt, J.; Yang, S.

    1982-01-01

    DNA-protein and DNA interstrand cross-links were induced in isolated chromatin after treatment with H/sub 2/O/sub 2/ and ferrous ethylenediaminetetraacetate (EDTA). Retention of DNA on membrane filters after heating of chromatin in a dissociating solvent indicated the presence of a stable linkage between DNA and protein. Treatment of protein-free DNA with H/sub 2/O/sub 2//Fe/sup 2 +/-EDTA did not result in enhanced filter retention. Incubation of cross-linked chromatin with proteinase K completely eliminated filter retention. Resistance to S/sub 1/ nuclease after a denaturation-renaturation cycle was used to detect DNA interstrand cross-links. Heating the treated chromatin at 45/sup 0/C for 16 h and NaBH/sub 4/ reduction enhanced the extent of interstrand cross-linking. The following data are consistent with, but do not totally prove, the hypothesis that cross-links are induced by hydroxyl radicals generated in Fenton-type reactions: (1) cross-linking was inhibited by hydroxyl radical scavengers; (2) the degree of inhibition of DNA interstrand cross-links correlated very closely with the rate constants of the scavengers for reaction with hydroxyl radicals; (3) cross-linking was eliminated or greatly reduced by catalase; (4) the extent of cross-linking was directly related to the concentration of Fe/sup 2 +/-EDTA. Partial inhibition of cross-linking by superoxide dismutase indicates that super-oxide-driven Fenton chemistry is involved. The data indicate that DNA cross-linking may play a role in the manifestation of the biological activity of agents of systems that generate reactive hydroxyl radicals.

  12. Synthesis, growth and characterization of organic nonlinear optical bis-glycine maleate (BGM) single crystals

    NASA Astrophysics Data System (ADS)

    Balasubramanian, D.; Murugakoothan, P.; Jayavel, R.

    2010-05-01

    A new organic compound of bis-glycine maleate was synthesized in the alkaline medium of 10% ammonium hydroxide solution. The bulk single crystals of Bis-Glycine Maleate (BGM) have been grown by slow cooling method. The grown crystals were characterized by employing single crystal and powder X-ray diffraction, Fourier transform infrared, optical absorption spectral studies and thermo gravimetric analysis. The microhardness studies confirmed that the BGM has a fairly high Vicker's hardness number value (41 kg mm -2) in comparison to other organic NLO crystals. Second harmonic generation efficiency of the crystal measured by Kurtz-Perry powder method using Nd:YAG laser is found to be comparable to that of potassium dihydrogen phosphate (KDP). Frequency dependent dielectric studies were carried out along the major growth axis.

  13. Growth and characterization of a nonlinear optical crystal: Bisglycine hydrogen chloride

    NASA Astrophysics Data System (ADS)

    Chandra, Ch. Sateesh; Krishna, N. Gopi; Raja Shekar, P. V.; Nagaraju, D.

    2013-02-01

    Single crystals of bisglycine hydrogen chloride (BGHC), a semiorganic nonlinear optical crystal, of dimensions 13×6×4 mm3 were grown in a period of 10 days. The grown crystals were confirmed by powder XRD, FTIR and DSC studies. For the first time, the defect content present in the crystals was estimated by chemical etching studies. The results indicate that the average dislocation density is about 3.1×103/cm2. The load-hardness curves for BGHC were studied over the load range 10-100 g. The UV-Vis. studies indicate that the crystal has a wide transmission range. The Kurtz powder test indicates that the second harmonic generation efficiency of BGHC is almost two times that of KDP.

  14. Structural, optical and dielectric studies of novel non-linear Bisglycine Lithium Nitrate piezoelectric single crystal

    NASA Astrophysics Data System (ADS)

    Dalal, Jyoti; Sinha, Nidhi; Kumar, Binay

    2014-11-01

    The novel non-linear semiorganic Bisglycine Lithium Nitrate (BGLiN) single crystals were grown by slow evaporation technique. The structural analysis revealed that it belongs to non-centrosymmetric orthorhombic structure. The presence of various functional groups in the grown crystal was confirmed by FTIR and Raman analysis. Surface morphology of the grown crystal was studied by scanning electron microscopy. The optical studies show that crystal has good transmittance (more than 80%) in the entire visible region and a wide band gap (5.17 eV). The optical constants such as extinction coefficient (K), the reflectance (R) and refractive index (n) as a function of photon energy were calculated from the optical measurements. With the help of these optical constants the electric susceptibility (?c) and both the real (?r) and imaginary (?i) parts of the dielectric constants were also calculated which are required to develop optoelectronic devices. In photoluminescence studies, a broad emission band centered at 404 nm was found in addition to a small band at 352 nm. A broad transition (from 29 to 33 C) was observed with low dielectric constant value. A high piezoelectric charge coefficient (d33) of 14 pC/N was measured at room temperature which implies its usefulness for various sensor applications. The second harmonic generation efficiency of crystal was found to be 1.5 times to that of KDP. From thermo gravimetric analysis and differential thermal analysis, thermal stability and melting point (246 C) were investigated. The dielectric behavior, optical characterization, piezoelectric behavior and the non-linear optical properties of the Bisglycine Lithium Nitrate single crystals were reported for the first time which established the usefulness of these crystals for various piezo- and opto-electronics applications.

  15. 21 CFR 184.1315 - Ferrous sulfate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...SO4·7H2O, CAS Reg. No. 7782-63-0) is prepared by the action of sulfuric acid on iron. It occurs as... ferrous sulfate (dried). Ferrous sulfate (dried) consists primarily of ferrous sulfate monohydrate...

  16. Study of Vitamins and Dietary Supplements Containing Ferrous Fumarate and Ferrous Sulfate Using Moessbauer Spectroscopy

    SciTech Connect

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

    2010-07-13

    A study of several samples of vitamins and dietary supplements containing ferrous fumarate and ferrous sulfate was carried out using Moessbauer spectroscopy with a high velocity resolution. A presence of ferrous and ferric impurities was revealed. Small variations of Moessbauer hyperfine parameters were found for both ferrous fumarates and ferrous sulfates in the investigated medicines.

  17. Comment on the paper by R. Sankar, C.M. Ragahvan, R. Mohan Kumar, R. Jayavel, Growth and characterization of bis-glycine sodium nitrate (BGSN), a novel semiorganic nonlinear optical crystal, J. Crystal Growth 309 (2007) 30 36

    NASA Astrophysics Data System (ADS)

    Petrosyan, A. M.

    2008-08-01

    It is argued that the conclusion of the authors of the title paper on obtaining of a new crystal bis-glycine sodium nitrate is erroneous. From an aqueous solution containing 2 glycine+NaNO 3 the authors actually have obtained earlier known crystals: glycine (alpha form) and glycine sodium nitrate.

  18. Hydroxypyridonate chelating agents

    SciTech Connect

    Raymond, K.N.; Scarrow, R.C.; White, D.L.

    1987-10-06

    Chelating agents are disclosed having 1-hydroxy-2-pyridinone (HOPO) and related moieties incorporated within their structures, including polydentate HOPO-substituted polyamines such as spermidine and spermine, and HOPO-substituted desferrioxamine. The chelating agents are useful in selectively removing certain cations from solution, and are particularly useful as ferric ion and actinide chelators. Novel syntheses of the chelating agents are provided.

  19. Hydroxypyridonate chelating agents

    DOEpatents

    Raymond, Kenneth N. (Berkeley, CA); Scarrow, Robert C. (Minneapolis, MN); White, David L. (Oakland, CA)

    1987-01-01

    Chelating agents having 1-hydroxy-2-pyridinone (HOPO) and related moieties incorporated within their structures, including polydentate HOPO-substituted polyamines such as spermidine and spermine, and HOPO-substituted desferrioxamine. The chelating agents are useful in selectively removing certain cations from solution, and are particularly useful as ferric ion and actinide chelators. Novel syntheses of the chelating agents are provided.

  20. Fluorescent Pseudomonad Pyoverdines Bind and Oxidize Ferrous Ion

    PubMed Central

    Xiao, Rong; Kisaalita, William S.

    1998-01-01

    Major pyoverdines from Pseudomonas fluorescens 2-79 (Pf-B), P. aeruginosa ATCC 15692 (Pa-C), and P. putida ATCC 12633 (Pp-C) were examined by absorption and fluorescence spectroscopic techniques to investigate the interaction between ferrous ion and the pyoverdine ligand. At physiological pH, ferrous ion quenched the fluorescence of all three pyoverdines much faster than ferric ion did. Also, increased absorbance at 460 nm was observed to be much faster for Fe2+-pyoverdine than for Fe3+-pyoverdine. At pH 7.4, about 90% of Fe3+ was bound by pyoverdine Pa-C after 24 h whereas Fe2+ was bound by the pyoverdine completely in only 5 min. The possibility that Fe2+ underwent rapid autoxidation before being bound by pyoverdine was considered unlikely, since the Fe2+ concentration in pyoverdine-free samples remained constant over a 3-min period at pH 7.4. Incubating excess Fe2+ with pyoverdine in the presence of 8-hydroxyquinoline, an Fe3+-specific chelating agent, resulted in the formation of a Fe3+-hydroxyquinoline complex, suggesting that the iron in the Fe2+-pyoverdine complex existed in the oxidized form. These results strongly suggested that pyoverdines bind and oxidize the ferrous ion. PMID:9575133

  1. 21 CFR 184.1308 - Ferrous gluconate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...-yellow powder or granules. It is prepared by reacting hot solutions of barium or calcium gluconate with ferrous sulfate or by heating freshly prepared ferrous carbonate with gluconic acid in aqueous...

  2. 21 CFR 73.160 - Ferrous gluconate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... ferrous gluconate is the ferrous gluconate defined in the Food Chemicals Codex, 3d Ed. (1981), pp. 122-123... shall meet the specifications given in the Food Chemicals Codex, 3d Ed. (1981), which is incorporated...

  3. 21 CFR 73.160 - Ferrous gluconate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... ferrous gluconate is the ferrous gluconate defined in the Food Chemicals Codex, 3d Ed. (1981), pp. 122-123... shall meet the specifications given in the Food Chemicals Codex, 3d Ed. (1981), which is incorporated...

  4. 21 CFR 73.160 - Ferrous gluconate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... ferrous gluconate is the ferrous gluconate defined in the Food Chemicals Codex, 3d Ed. (1981), pp. 122-123... shall meet the specifications given in the Food Chemicals Codex, 3d Ed. (1981), which is incorporated...

  5. 21 CFR 73.160 - Ferrous gluconate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... ferrous gluconate is the ferrous gluconate defined in the Food Chemicals Codex, 3d Ed. (1981), pp. 122-123... shall meet the specifications given in the Food Chemicals Codex, 3d Ed. (1981), which is incorporated...

  6. 21 CFR 73.160 - Ferrous gluconate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... ferrous gluconate is the ferrous gluconate defined in the Food Chemicals Codex, 3d Ed. (1981), pp. 122-123... shall meet the specifications given in the Food Chemicals Codex, 3d Ed. (1981), which is incorporated...

  7. 21 CFR 582.5311 - Ferrous lactate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 582.5311 Ferrous lactate. (a) Product. Ferrous lactate. (b) Conditions of use. This...

  8. 21 CFR 582.5308 - Ferrous gluconate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 582.5308 Ferrous gluconate. (a) Product. Ferrous gluconate. (b) Conditions of use....

  9. 21 CFR 582.5315 - Ferrous sulfate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 582.5315 Ferrous sulfate. (a) Product. Ferrous sulfate. (b) Conditions of use. This...

  10. 21 CFR 582.5311 - Ferrous lactate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 582.5311 Ferrous lactate. (a) Product. Ferrous lactate. (b) Conditions of use. This...

  11. 21 CFR 582.5315 - Ferrous sulfate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 582.5315 Ferrous sulfate. (a) Product. Ferrous sulfate. (b) Conditions of use. This...

  12. 21 CFR 582.5311 - Ferrous lactate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 582.5311 Ferrous lactate. (a) Product. Ferrous lactate. (b) Conditions of use. This...

  13. 21 CFR 582.5308 - Ferrous gluconate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 582.5308 Ferrous gluconate. (a) Product. Ferrous gluconate. (b) Conditions of use....

  14. 21 CFR 582.5308 - Ferrous gluconate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 582.5308 Ferrous gluconate. (a) Product. Ferrous gluconate. (b) Conditions of use....

  15. 21 CFR 582.5315 - Ferrous sulfate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 582.5315 Ferrous sulfate. (a) Product. Ferrous sulfate. (b) Conditions of use. This...

  16. 21 CFR 184.1311 - Ferrous lactate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... lactic acid with iron filings, reaction of ferrous chloride with sodium lactate, or reaction of ferrous...) and 1 CFR part 51. Copies are available from the National Academy Press, 2101 Constitution Ave....

  17. 21 CFR 184.1311 - Ferrous lactate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... lactic acid with iron filings, reaction of ferrous chloride with sodium lactate, or reaction of ferrous...) and 1 CFR part 51. Copies are available from the National Academy Press, 2101 Constitution Ave....

  18. 21 CFR 184.1311 - Ferrous lactate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... lactic acid with iron filings, reaction of ferrous chloride with sodium lactate, or reaction of ferrous...) and 1 CFR part 51. Copies are available from the National Academy Press, 2101 Constitution Ave....

  19. 46 CFR 148.260 - Ferrous metal.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Ferrous metal. 148.260 Section 148.260 Shipping COAST... THAT REQUIRE SPECIAL HANDLING Special Requirements for Certain Materials § 148.260 Ferrous metal. (a... waters of United States. (b) Ferrous metal may not be stowed or transported in bulk unless the...

  20. 46 CFR 148.260 - Ferrous metal.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Ferrous metal. 148.260 Section 148.260 Shipping COAST... THAT REQUIRE SPECIAL HANDLING Special Requirements for Certain Materials § 148.260 Ferrous metal. (a... waters of United States. (b) Ferrous metal may not be stowed or transported in bulk unless the...

  1. 46 CFR 148.260 - Ferrous metal.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Ferrous metal. 148.260 Section 148.260 Shipping COAST... THAT REQUIRE SPECIAL HANDLING Special Requirements for Certain Materials § 148.260 Ferrous metal. (a... waters of United States. (b) Ferrous metal may not be stowed or transported in bulk unless the...

  2. 21 CFR 184.1315 - Ferrous sulfate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... heptahydrate, FeSO4·7H2O, CAS Reg. No. 7782-63-0) is prepared by the action of sulfuric acid on iron. It occurs... produces ferrous sulfate (dried). Ferrous sulfate (dried) consists primarily of ferrous sulfate...

  3. 21 CFR 582.5315 - Ferrous sulfate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Ferrous sulfate. 582.5315 Section 582.5315 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Supplements 1 582.5315 Ferrous sulfate. (a) Product. Ferrous sulfate. (b) Conditions of use. This...

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

    SciTech Connect

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

    1987-05-01

    The uptake of radiolabeled transferrin and iron by the rat placenta has been studied using two approaches. The first involved injection of a ferrous or ferric iron chelator followed by injection of label. Neither chelator decreased the amount of labelled transferrin in the placenta after 2-h incubation and only bipyridine, a ferrous iron chelator, inhibited iron transport to the fetus. Deferoxamine (DFO), a ferric iron chelator, had no effect on iron transport to the fetus but reduced iron uptake by the liver. Both bipyridine and DFO increased iron excretion into the gut and by the urinary tract to the same degree into the gut, but there was a 10-fold greater urinary excretion with bipyridine than with DFO. Injection of iron attached to the chelators showed that neither bipyridine nor DFO could donate iron to the fetus as efficiently as transferrin. The mechanism involved was further investigated by studying the effect of the chelators on uptake of transferrin-bound iron by placental cells in culture. DFO inhibited iron accumulation more effectively than bipyridine in the cultured cells. The effect was not due to a decrease in the cycling time of the receptor. The results can be explained if the iron is released from the transferrin in intracellular vesicles in the ferrous form, where it may be chelated by bipyridine and prevented from passing to the fetus or converted to the ferric form once it is inside the cell matrix.

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

    NASA Astrophysics Data System (ADS)

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

    2010-04-01

    Several commercially available medicaments containing ferrous fumarate (FeC4H2O4) and ferrous sulfate (FeSO4), as a source of ferrous iron, were studied using a high velocity resolution Mssbauer spectroscopy. A comparison of the 57Fe hyperfine parameters revealed small variations for the main components in both medicaments indicating some differences in the ferrous fumarates and ferrous sulfates. It was also found that all spectra contained additional minor components probably related to ferrous and ferric impurities or to partially modified main components.

  6. Chelation in Metal Intoxication

    PubMed Central

    Flora, Swaran J.S.; Pachauri, Vidhu

    2010-01-01

    Chelation therapy is the preferred medical treatment for reducing the toxic effects of metals. Chelating agents are capable of binding to toxic metal ions to form complex structures which are easily excreted from the body removing them from intracellular or extracellular spaces. 2,3-Dimercaprol has long been the mainstay of chelation therapy for lead or arsenic poisoning, however its serious side effects have led researchers to develop less toxic analogues. Hydrophilic chelators like meso-2,3-dimercaptosuccinic acid effectively promote renal metal excretion, but their ability to access intracellular metals is weak. Newer strategies to address these drawbacks like combination therapy (use of structurally different chelating agents) or co-administration of antioxidants have been reported recently. In this review we provide an update of the existing chelating agents and the various strategies available for the treatment of heavy metals and metalloid intoxications. PMID:20717537

  7. Macrocyclic bifunctional chelating agents

    DOEpatents

    Meares, Claude F. (Davis, CA); DeNardo, Sally J. (El Macero, CA); Cole, William C. (Houston, TX); Mol, Min K. (Davis, CA)

    1987-01-01

    A copper chelate conjugate which is stable in human serum. The conjugate includes the copper chelate of a cyclic tetraaza di-, tri-, or tetra-acetic acid, a linker attached at one linker end to a ring carbon of the chelate, and a biomolecule joined at the other end of the linker. The conjugate, or the linker-copper chelate compound used in forming the conjugate, are designed for use in diagnostic and therapeutic applications which involve Cu(II) localization via the systemic route.

  8. The Rules of Ferrous Metallurgy

    PubMed Central

    2010-01-01

    The ways in which the sciences have been delineated and categorized throughout history provide insights into the formation, stabilization, and establishment of scientific systems of knowledge. The Dresdener school’s approach for explaining and categorizing the genesis of the engineering disciplines is still valid, but needs to be complemented by further-reaching methodological and theoretical reflections. Pierre Bourdieu’s theory of social practice is applied to the question of how individual agents succeed in influencing decisively a discipline’s changing object orientation, institutionalisation and self-reproduction. Through the accumulation of social, cultural and economic capital, they succeed in realising their own organisational ideas and scientific programs. Key concepts for the analysis include the struggle for power and resources, monopolies of interpretation, and the degree of autonomy. A case study from the Aachener Technische Hochschule shows that the consolidation of ferrous metallurgy can be conceived as a symbolical struggle between Fritz Wüst, professor for ferrous metallurgy, and the German Iron and Steel Institute, leading to a construction of a system of differences in which scientists accepted being scientists rather than entrepreneurs, and entrepreneurs accepted becoming entrepreneurs and renounced science.

  9. Study of Vitamins and Dietary Supplements Containing Ferrous Fumarate and Ferrous Sulfate Using Mössbauer Spectroscopy

    NASA Astrophysics Data System (ADS)

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

    2010-07-01

    A study of several samples of vitamins and dietary supplements containing ferrous fumarate and ferrous sulfate was carried out using Mössbauer spectroscopy with a high velocity resolution. A presence of ferrous and ferric impurities was revealed. Small variations of Mössbauer hyperfine parameters were found for both ferrous fumarates and ferrous sulfates in the investigated medicines.

  10. 21 CFR 73.165 - Ferrous lactate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... is incorporated by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies are... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Ferrous lactate. 73.165 Section 73.165 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Foods 73.165 Ferrous lactate. (a) Identity. The color additive...

  11. 21 CFR 73.165 - Ferrous lactate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... is incorporated by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies are... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Ferrous lactate. 73.165 Section 73.165 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Foods 73.165 Ferrous lactate. (a) Identity. The color additive...

  12. 46 CFR 148.260 - Ferrous metal.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Ferrous metal. 148.260 Section 148.260 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) DANGEROUS CARGOES CARRIAGE OF BULK SOLID MATERIALS THAT REQUIRE SPECIAL HANDLING Special Requirements for Certain Materials § 148.260 Ferrous metal. (a) This part does not apply to the stowage...

  13. 21 CFR 184.1308 - Ferrous gluconate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... Specific Substances Affirmed as GRAS 184.1308 Ferrous gluconate. (a) Ferrous gluconate (iron (II) gluconate dihydrate, C12H22FeO142H2O, CAS Reg. No. 6047-12-7) is a fine yellowish-gray or pale...

  14. 21 CFR 184.1308 - Ferrous gluconate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... Specific Substances Affirmed as GRAS 184.1308 Ferrous gluconate. (a) Ferrous gluconate (iron (II) gluconate dihydrate, C12H22FeO142H2O, CAS Reg. No. 6047-12-7) is a fine yellowish-gray or pale...

  15. 21 CFR 184.1308 - Ferrous gluconate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... Specific Substances Affirmed as GRAS 184.1308 Ferrous gluconate. (a) Ferrous gluconate (iron (II) gluconate dihydrate, C12H22FeO142H2O, CAS Reg. No. 6047-12-7) is a fine yellowish-gray or pale...

  16. 21 CFR 184.1308 - Ferrous gluconate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Ferrous gluconate. 184.1308 Section 184.1308 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DIRECT FOOD SUBSTANCES AFFIRMED AS GENERALLY RECOGNIZED AS SAFE Listing of Specific Substances Affirmed as GRAS 184.1308 Ferrous gluconate. (a)...

  17. 21 CFR 582.5315 - Ferrous sulfate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Ferrous sulfate. 582.5315 Section 582.5315 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 582.5315 Ferrous sulfate. (a)...

  18. 21 CFR 582.5308 - Ferrous gluconate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Ferrous gluconate. 582.5308 Section 582.5308 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 582.5308 Ferrous gluconate....

  19. 21 CFR 582.5311 - Ferrous lactate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Ferrous lactate. 582.5311 Section 582.5311 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 582.5311 Ferrous lactate. (a)...

  20. The Chelate Effect Redefined.

    ERIC Educational Resources Information Center

    da Silva, J. J. R. Frausto

    1983-01-01

    Discusses ambiguities of the accepted definition of the chelate effect, suggesting that it be defined in terms of experimental observation rather than mathematical abstraction. Indicates that the effect depends on free energy change in reaction, ligand basicity, pH of medium, type of chelates formed, and concentration of ligands in solution. (JN)

  1. Ferrous iron transport in Streptococcus mutans

    SciTech Connect

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

    1986-12-01

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

  2. Chelation of cadmium

    SciTech Connect

    Andersen, O.

    1984-03-01

    The toxicity of cadmium is determined by chelation reactions: in vivo, Cd/sup 2 +/ exists exclusively in coordination complexes with biological ligands, or with administered chelating agents. The mechanism of action of the Cd-metallothionein complex and of various chelating agents is described. During acute treatment of Cd/sup 2 +/ poisoning the superior agents seem to be the polyamino-polycarboxylates, especially DTPA, which increases renal excretion. The time lapse between Cd intoxication and antidote administration is critical due to the rapid intracellular accumulation of Cd/sup 2 -/, mainly in liver. During chronic Cd/sup 2 +/ exposure, BAL significantly increases biliary excretion of Cd/sup 2 +/, and part of the mobilized Cd/sup 2 +/ is chelated out of MT. 128 references, 4 figures, 11 tables.

  3. 21 CFR 184.1311 - Ferrous lactate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... reacting calcium lactate or sodium lactate with ferrous sulfate, direct reaction of lactic acid with iron... to 155, which is incorporated by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part...

  4. 21 CFR 184.1311 - Ferrous lactate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... prepared by reacting calcium lactate or sodium lactate with ferrous sulfate, direct reaction of lactic acid.... (1996), pp. 154 to 155, which is incorporated by reference in accordance with 5 U.S.C. 552(a) and 1...

  5. POLYCYCLIC AROMATIC HYDROCARBONS AND PHENOLICS IN FERROUS AND NON-FERROUS WASTE FOUNDRY SANDS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A total of 43 sets of waste sand were collected from ferrous and non-ferrous foundries in the eastern United States. The concentration of organic compounds known as polycyclic aromatic hydrocarbons (PAHs) and phenolics were determined. These compounds are known to be toxic to humans. Since there ...

  6. Iron Chelation Therapy

    MedlinePLUS

    ... iron overload. Deferasirox ( Exjade ) . Deferasirox is a newer iron chelating medication that comes in a tablet form. It is dissolved in juice or water and taken (by mouth) once a day. Most patients tolerate it very well, but side effects can include nausea, diarrhea, rash, and more serious ...

  7. Non-ferrous metal data yearbook 1986

    SciTech Connect

    Not Available

    1986-01-01

    Non-Ferrous Metal Data Yearbook has been published annually since 1920. It contains data on metals production for five comparative years and has over 180 statistical tables for (1) imports and exports, (2) mine, smelter, and refined production, (3) inventory tonnages, and (4) listed prices for each metal. Significant non-ferrous metals include copper, lead, zinc, aluminum, silver, gold, antimony, cadmium, magnesium, molybdenum, cobalt, nickel, platinum, selenium, tellurium, titanium, tin, and uranium. Included in the yearbook is an extensive listing of the names, and in some cases, addresses of major producers, smelters, and refiners.

  8. 21 CFR 184.1315 - Ferrous sulfate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...) sulfate heptahydrate, FeSO4·7H2O, CAS Reg. No. 7782-63-0) is prepared by the action of sulfuric acid on... monohydrate (CAS Reg. No. 17375-41-6) with varying amounts of ferrous sulfate tetrahydrate (CAS Reg. No....

  9. 21 CFR 184.1315 - Ferrous sulfate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...) sulfate heptahydrate, FeSO4·7H2O, CAS Reg. No. 7782-63-0) is prepared by the action of sulfuric acid on... monohydrate (CAS Reg. No. 17375-41-6) with varying amounts of ferrous sulfate tetrahydrate (CAS Reg. No....

  10. 21 CFR 184.1315 - Ferrous sulfate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...) sulfate heptahydrate, FeSO4·7H2O, CAS Reg. No. 7782-63-0) is prepared by the action of sulfuric acid on... monohydrate (CAS Reg. No. 17375-41-6) with varying amounts of ferrous sulfate tetrahydrate (CAS Reg. No....

  11. 21 CFR 73.165 - Ferrous lactate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... is incorporated by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies are... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Ferrous lactate. 73.165 Section 73.165 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF...

  12. 21 CFR 73.165 - Ferrous lactate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... is incorporated by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies are... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Ferrous lactate. 73.165 Section 73.165 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF...

  13. 21 CFR 73.165 - Ferrous lactate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... is incorporated by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies are... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Ferrous lactate. 73.165 Section 73.165 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF...

  14. Bacterial ferrous iron transport: the Feo system.

    PubMed

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

    2016-03-01

    To maintain iron homeostasis within the cell, bacteria have evolved various types of iron acquisition systems. Ferric iron (Fe(3+)) is the dominant species in an oxygenated environment, while ferrous iron (Fe(2+)) is more abundant under anaerobic conditions or at low pH. For organisms that must combat oxygen limitation for their everyday survival, pathways for the uptake of ferrous iron are essential. Several bacterial ferrous iron transport systems have been described; however, only the Feo system appears to be widely distributed and is exclusively dedicated to the transport of iron. In recent years, many studies have explored the role of the FeoB and FeoA proteins in ferrous iron transport and their contribution toward bacterial virulence. The three-dimensional structures for the Feo proteins have recently been determined and provide insight into the molecular details of the transport system. A highly select group of bacteria also express the FeoC protein from the same operon. This review will provide a comprehensive look at the structural and functional aspects of the Feo system. In addition, bioinformatics analyses of the feo operon and the Feo proteins have been performed to complement our understanding of this ubiquitous bacterial uptake system, providing a new outlook for future studies. PMID:26684538

  15. 46 CFR 56.60-3 - Ferrous materials.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Ferrous materials. 56.60-3 Section 56.60-3 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PIPING SYSTEMS AND APPURTENANCES Materials 56.60-3 Ferrous materials. (a) Ferrous pipe used for salt water service must...

  16. 46 CFR 56.60-3 - Ferrous materials.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 2 2014-10-01 2014-10-01 false Ferrous materials. 56.60-3 Section 56.60-3 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PIPING SYSTEMS AND APPURTENANCES Materials 56.60-3 Ferrous materials. (a) Ferrous pipe used for salt water service must...

  17. 46 CFR 56.60-3 - Ferrous materials.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Ferrous materials. 56.60-3 Section 56.60-3 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PIPING SYSTEMS AND APPURTENANCES Materials 56.60-3 Ferrous materials. (a) Ferrous pipe used for salt water service must...

  18. 46 CFR 56.60-3 - Ferrous materials.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 false Ferrous materials. 56.60-3 Section 56.60-3 Shipping... APPURTENANCES Materials § 56.60-3 Ferrous materials. (a) Ferrous pipe used for salt water service must be protected against corrosion by hotdip galvanizing or by the use of extra heavy schedule material....

  19. 46 CFR 56.60-3 - Ferrous materials.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 2 2012-10-01 2012-10-01 false Ferrous materials. 56.60-3 Section 56.60-3 Shipping... APPURTENANCES Materials § 56.60-3 Ferrous materials. (a) Ferrous pipe used for salt water service must be protected against corrosion by hotdip galvanizing or by the use of extra heavy schedule material....

  20. Oxidation of Ferrous Iron and Elemental Sulfur by Thiobacillus ferrooxidans

    PubMed Central

    Espejo, Romilio T.; Escobar, Blanca; Jedlicki, Eugenia; Uribe, Paulina; Badilla-Ohlbaum, Ricardo

    1988-01-01

    The oxidation of ferrous iron and elemental sulfur by Thiobacillus ferrooxidans that was absorbed and unabsorbed onto the surface of sulfur prills was studied. Unadsorbed sulfur-grown cells oxidized ferrous iron at a rate that was 3 to 7 times slower than that of ferrous iron-grown cells, but sulfur-grown cells were able to reach the oxidation rate of the ferrous iron-adapted cells after only 1.5 generations in a medium containing ferrous iron. Bacteria that were adsorbed to sulfur prills oxidized ferrous iron at a rate similar to that of unadsorbed sulfur-grown bacteria. They also showed the enhancement of ferrous iron oxidation activity in the presence of ferrous iron, even though sulfur continued to be available to the bacteria in this case. An increase in the level of rusticyanin together with the enhancement of the ferrous iron oxidation rate were observed in both sulfur-adsorbed and unadsorbed cells. On the other hand, sulfur oxidation by the adsorbed bacteria was not affected by the presence of ferrous iron in the medium. When bacteria that were adsorbed to sulfur prills were grown at a higher pH (ca. 2.5) in the presence of ferrous iron, they rapidly lost both ferrous iron and sulfur oxidation capacities and became inactive, apparently because of the deposition of a jarosite-like precipitate onto the surface to which they were attached. Images PMID:16347681

  1. Rigid bifunctional chelating agents

    DOEpatents

    Sweet, M.P.; Mease, R.C.; Srivastava, S.C.

    1998-07-21

    Bicyclo[2.2.2] octane-2,3 diamine-N,N,N`,N`-tetraacetic acids (BODTA) and bicyclo[2.2.1] heptane-2,3 diamine-N,N,N`,N`-tetraacetic acid (BHDTA) are chelating agents useful in forming detectably labeled bioconjugate compounds for diagnostic and therapeutic purposes. New compounds and processes of forming BODTA and BHDTA are disclosed. Radioimmunoconjugates of the present invention show high and prolonged tumor uptake with low normal tissue uptakes.

  2. Rigid bifunctional chelating agents

    DOEpatents

    Sweet, Mark P. (Coram, NY); Mease, Ronnie C. (Fairfax, VA); Srivastava, Suresh C. (Setauket, NY)

    2000-02-08

    Bicyclo[2.2.2]octane-2,3 diamine-N,N,N',N'-tetraacetic acids (BODTA) and bicyclo[2.2.1]heptane-2,3 diamine-N,N,N',N'-tetraacetic acid (BHDTA) are chelating agents useful in forming detectably labeled bioconjugate compounds for diagnostic and therapeutic purposes. New compounds and processes of forming BODTA and BHDTA are disclosed. Radioimmunoconjugates of the present invention show high and prolonged tumor uptake with low normal tissue uptakes.

  3. Rigid bifunctional chelating agents

    DOEpatents

    Sweet, Mark P. (Coram, NY); Mease, Ronnie C. (Fairfax, VA); Srivastava, Suresh C. (Setauket, NY)

    1998-07-21

    Bicyclo2.2.2! octane-2,3 diamine-N,N,N',N'-tetraacetic acids (BODTA) and bicyclo2.2.1! heptane-2,3 diamine-N,N,N',N'-tetraacetic acid (BHDTA) are chelating agents useful in forming detectably labeled bioconjugate compounds for diagnostic and therapeutic purposes. New compounds and processes of forming BODTA and BHDTA are disclosed. Radioimmunoconjugates of the present invention show high and prolonged tumor uptake with low normal tissue uptakes.

  4. Natural chelates for radionuclide decorporation

    DOEpatents

    Premuzic, E.T.

    1983-08-25

    This invention relates to the method and resulting chelates of desorbing a radionuclide selected from thorium, uranium, and plutonium containing cultures in a bioavailable form involving pseudomonas or other microorganisms. A preferred microorganism is Pseudomonas aeruginosa which forms multiple chelates with thorium in the range of molecular weight 1000 to 1000 and also forms chelates with uranium of molecular weight in the area of 100 to 1000 and 1000 to 2000.

  5. Chelation of cadmium.

    PubMed Central

    Andersen, O

    1984-01-01

    The toxicity of cadmium is determined by chelation reactions: in vivo, Cd2+ exists exclusively in coordination complexes with biological ligands, or with administered chelating agents. The Cd2+ ion has some soft character, but it is not a typical soft ion. It has a high degree of polarizability, and its complexes with soft ligands have predominantly covalent bond characteristics. Cd2+ forms the most stable complexes with soft donor atoms (S much greater than N greater than 0). The coordination stereochemistry of Cd2+ is unusually varied, including coordination numbers from 2 to 8. Even though the Cd2+ ion is a d10 ion, disturbed coordination geometries are often seen. Generally, the stability of complexes increases with the number of coordination groups contributed by the ligand; consequently, complexes of Cd2+ with polydentate ligands containing SH groups are very stable. Cd2+ in metallothionein (MT) is coordinated with 4 thiolate groups, and the log stability constant is estimated to 25.5. Complexes between Cd2+ and low molecular weight monodentate or bidentate ligands, e.g., free amino acids (LMW-Cd), seem to exist very briefly, and Cd2+ is rapidly bound to high molecular weight proteins, mainly serum albumin. These complexes (HMW-Cd) are rapidly scavenged from blood, mainly by the liver, and Cd2+ is redistributed to MT. After about 1 day the Cd-MT complex (MT-Cd) almost exclusively accounts for the total retained dose of Cd2+, independent of the route of exposure. MT-Cd is slowly transferred to and accumulated in kidney cortex. The acute toxicity and interorgan distribution of parenterally administered Cd2+ are strongly influenced by preceding MT induction, or decreased capacity for MT synthesis; however, the gastrointestinal (GI) uptake of Cd2+ seems unaffected by preceding MT induction resulting in considerable capacity for Cd2+ chelation in intestinal mucosa, and this finding indicates that endogenous MT is not involved in Cd2+ absorption. The toxicity of parenterally administered Cd2+ is strongly enhanced when administered as complexes with NTA or STPP , but it is much decreased when administered as a complex with EDTA. In chronic oral exposure the toxicity and GI uptake of Cd2+ is not changed when Cd2+ is administered as a complex with the detergent formula chelating agents NTA, EDTA and STPP . The uptake of Cd2+ from ligated intestine in vivo was not affected by administration of Cd2+ as complexes with CYS or GSH, but significantly reduced by complexation with EDTA or BAL. The acute toxicity of orally administered Cd2+ is reduced when Cd2+ is administered as a complex with EDTA.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:6734560

  6. Removal of copper from ferrous scrap

    DOEpatents

    Blander, M.; Sinha, S.N.

    1990-05-15

    A process for removing copper from ferrous or other metal scrap in which the scrap is contacted with a polyvalent metal sulfide slag in the presence of an excess of copper-sulfide forming additive to convert the copper to copper sulfide which is extracted into the slag to provide a ratio of copper in the slag to copper in the metal scrap of at least about 10.

  7. Removal of copper from ferrous scrap

    DOEpatents

    Blander, M.; Sinha, S.N.

    1987-07-30

    A process for removing copper from ferrous or other metal scrap in which the scrap is contacted with a polyvalent metal sulfide slag in the presence of an excess of copper-sulfide forming additive to convert the copper to copper sulfide which is extracted into the slag to provide a ratio of copper in the slag to copper in the metal scrap of at least about 10.

  8. Removal of copper from ferrous scrap

    DOEpatents

    Blander, Milton (12833 S. 82nd Ct., Palos Park, IL 60464); Sinha, Shome N. (5748 Drexel, 2A, Chicago, IL 60637)

    1990-01-01

    A process for removing copper from ferrous or other metal scrap in which the scrap is contacted with a polyvalent metal sulfide slag in the presence of an excess of copper-sulfide forming additive to convert the copper to copper sulfide which is extracted into the slag to provide a ratio of copper in the slag to copper in the metal scrap of at least about 10.

  9. Novel fluorescent chelate for Eu

    NASA Astrophysics Data System (ADS)

    Savitsky, Alexander P.; Chydinov, Alexander V.; Krilova, Svetlana M.

    1995-05-01

    Novel high efficient fluorescent chelate for Eu based on diethylenethriaminepentaacetic acid and amino (beta) -diketones is proposed for time-resolved fluorescence immunoassay. The label surpasses all known chelates for europium in major spectral and luminescent characteristics. The proposed label has number of advantages over the well-known europium chelates. The assays with new fluorescent chelate do not require enhancement solution, but the sensitivity of Eu determination is the same as for DELFIA enhancement solution. The assay with new fluorescent chelate is insensitive to contamination of solutions and samples with ions of heavy metals, because the concentration of fluorescent chelate is measured and high excess of Eu prevents dissociation of fluorescent chelate complex. Techniques have been developed for covalent labeling of proteins with the new fluorescent chelate. The labelling proteins can be stored in the lyophilized state or in stabilized solution rather long and retain their immunological properties. Application of the new fluorescent chelate enables the washing step to be avoided and to develop the express non-separation assay.

  10. Salmonella Acquires Ferrous Iron from Hemophagocytic Macrophages

    PubMed Central

    Nagy, Toni A.; Moreland, Sarah M.; Detweiler, Corrella S.

    2014-01-01

    SUMMARY Bacteria harbor both ferrous and ferric iron transporters. We now report that infection of macrophages and mice with a Salmonella enterica Typhimurium strain containing an inactivated feoB-encoded ferrous iron transporter results in increased bacterial replication, compared to infection with wild-type. Inactivation of other cation transporters, SitABCD or MntH, did not increase bacterial replication. The feoB mutant strain does not have an intrinsically faster growth rate. Instead, increased replication correlated with increased expression in macrophages of the fepB-encoded bacterial ferric iron transporter and also required siderophores, which capture ferric iron. Co-infection of mice with wild type and a feoB mutant strain yielded a different outcome: FeoB is clearly required for tissue colonization. In co-infected primary mouse macrophages, FeoB is required for S. Typhimurium replication if the macrophages were IFN? treated and contain phagocytosed erythrocytes, a model for hemophagocytosis. Hemophagocytes are macrophages that have engulfed erythrocytes and/or leukocytes and can harbor Salmonella in mice. These observations suggest that Salmonella acquires ferrous iron from hemophagocytic macrophages. PMID:25081030

  11. Salmonella acquires ferrous iron from haemophagocytic macrophages.

    PubMed

    Nagy, Toni A; Moreland, Sarah M; Detweiler, Corrella S

    2014-09-01

    Bacteria harbour both ferrous and ferric iron transporters. We now report that infection of macrophages and mice with a Salmonella enterica?Typhimurium strain containing an inactivated feoB-encoded ferrous iron transporter results in increased bacterial replication, compared to infection with wild type. Inactivation of other cation transporters, SitABCD or MntH, did not increase bacterial replication. The feoB mutant strain does not have an intrinsically faster growth rate. Instead, increased replication correlated with increased expression in macrophages of the fepB-encoded bacterial ferric iron transporter and also required siderophores, which capture ferric iron. Co-infection of mice with wild type and a feoB mutant strain yielded a different outcome: FeoB is clearly required for tissue colonization. In co-infected primary mouse macrophages, FeoB is required for S.?Typhimurium replication if the macrophages were IFN? treated and contain phagocytosed erythrocytes, a model for haemophagocytosis. Haemophagocytes are macrophages that have engulfed erythrocytes and/or leucocytes and can harbour Salmonella in mice. These observations suggest that Salmonella acquires ferrous iron from haemophagocytic macrophages. PMID:25081030

  12. Polycatecholamide chelating agents

    SciTech Connect

    Weitl, Frederick L.; Raymond, Kenneth N.

    1984-01-01

    Novel polybenzamide compounds useful for in vitro or in vivo chelation are described. The compounds have the formula ##STR1## Polyamines are reacted with 2,3-dimethoxy benzoyl chloride unsubstituted or substituted with SO.sub.3 H, SO.sub.3 M, NO.sub.2, CO.sub.2 H or CO.sub.2 M as desired is reacted with a polyamine in an inert solvent then demethylated with BBr.sub.3 or BCl.sub.3 in an inert solvent. Where compounds symmetrically substituted on the terminal N's are desired, the polyamine is first reductively alkylated by reaction with an aldehyde or ketone and the resulting Schiff base is hydrogenated.

  13. Novel polycatecholamide chelating agents

    DOEpatents

    Weitl, F.L.; Raymond, K.N.

    1981-08-24

    Novel polybenzamide compounds useful for in vitro or in vivo chelation are described. Formulas of the compounds are given. To prepare them polyamines are reacted with 2,3-dimethoxy benzoyl chloride unsubstituted or substituted with SO/sub 3/H, SO/sub 3/M, NO/sub 2/, CO/sub 2/H or CO/sub 2/M as desired is reacted with a polyamine in an inert solvent then demethylated with BBr/sub 3/ or BCl/sub 3/ in an inert solvent. Where compounds symmetrically substituted on the terminal N's are desired, the polyamine is first reductively alkylated by reaction with an aldehyde or ketone and the resulting Schiff base is hydrogenated.

  14. Polycatecholamide chelating agents

    DOEpatents

    Weitl, F.L.; Raymond, K.N.

    1984-04-10

    Novel polybenzamide compounds useful for in vitro or in vivo chelation are described. The compounds have the formula given in patent. Polyamines are reacted with 2,3-dimethoxy benzoyl chloride unsubstituted or substituted with SO[sub 3]H, SO[sub 3]M, NO[sub 2], CO[sub 2]H or CO[sub 2]M as desired is reacted with a polyamine in an inert solvent then demethylated with BBr[sub 3] or BCl[sub 3] in an inert solvent. Where compounds symmetrically substituted on the terminal N's are desired, the polyamine is first reductively alkylated by reaction with an aldehyde or ketone and the resulting Schiff base is hydrogenated. No Drawings

  15. 21 CFR 184.1307c - Ferrous citrate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Ferrous citrate. 184.1307c Section 184.1307c Food... GRAS § 184.1307c Ferrous citrate. (a) Ferrous citrate (iron (II) citrate, (C6H6FeO7), CAS Reg. No. 23383-11-1) is a slightly colored powder or white crystals. It is prepared from the reaction of...

  16. Ferrous iron oxidation by anoxygenic phototrophic bacteria

    NASA Astrophysics Data System (ADS)

    Widdel, Friedrich; Schnell, Sylvia; Heising, Silke; Ehrenreich, Armin; Assmus, Bernhard; Schink, Bernhard

    1993-04-01

    NATURAL oxidation of ferrous to ferric iron by bacteria such as Thiobacillus ferrooxidans or Gallionella ferruginea1, or by chemical oxidation2,3 has previously been thought always to involve molecular oxygen as the electron acceptor. Anoxic photochemical reactions4-6 or a photobiological process involving two photosystems7-9 have also been discussed as mechanisms of ferrous iron oxidation. The knowledge of such processes has implications that bear on our understanding of the origin of Precambrian banded iron formations10-14. The reducing power of ferrous iron increases dramatically at pH values higher than 2-3 owing to the formation of ferric hydroxy and oxyhydroxy compounds1,2,15 (Fig. 1). The standard redox potential of Fe3+/Fe2+ (E0 = +0.77 V) is relevant only under acidic conditions. At pH 7.0, the couples Fe(OH)3/Fe2+ (E'0 = -0.236V) or Fe(OH)3 + HCO-3FeCO3 (E'0 = +0.200 V) prevail, matching redox potentials measured in natural sediments9,16,17. It should thus be possible for Fe(n) around pH 7.0 to function as an electron donor for anoxygenic photosynthesis. The midpoint potential of the reaction centre in purple bacteria is around +0.45 V (ref. 18). Here we describe purple, non-sulphur bacteria that can indeed oxidize colourless Fe(u) to brown Fe(in) and reduce CO2 to cell material, implying that oxygen-independent biological iron oxidation was possible before the evolution of oxygenic photosynthesis.

  17. Hydroxypyridonate chelating agents and synthesis thereof

    DOEpatents

    Raymond, K.N.; Scarrow, R.C.; White, D.L.

    1985-11-12

    Chelating agents having 1-hydroxy-2-pyridinone (HOPO) and related moieties incorporated within their structures, including polydentate HOPO-substituted polyamines such as spermidine and spermine, and HOPO-substituted desferrioxamine. The chelating agents are useful in selectively removing certain cations from solution, and are particularly useful as ferric ion and actinide chelators. Novel syntheses of the chelating agents are provided. 4 tabs.

  18. A Reaction of Aspirin with Ferrous Gluconate.

    PubMed

    Zhang, Jian

    2015-12-01

    A color reaction of aspirin with ferrous gluconate was studied by UV-Vis spectrophotometry and HPLC-MS. It was found that the UV-Vis spectra of the two drugs were different before and after they were mixed in water at about 0.3M (diluted by>20 times for analysis), indicating that a complexation reaction took place. The drug-iron complex dissociated when the reacting solution was diluted by 400 times. The by-products of the reaction identified by HPLC-MS were salicylic acid, acetylated gluconic acid, salicylate-gluconic acid conjugate, and an oxidized product of salicylic acid that was complexed with iron with a molecular weight of 212. This reaction may be used as an important consideration to optimize the dosing regime of the two drugs and to help explain some pharmacological reactions between aspirin and biomolecules. PMID:25771741

  19. Fast Ferrous Heme-NO Oxidation in Nitric Oxide Synthases

    PubMed Central

    Tejero, Jess; Santolini, Jrme; Stuehr, Dennis J.

    2009-01-01

    During catalysis, the heme in nitric oxide synthase (NOS) binds NO before releasing it to the environment. Oxidation of the NOS ferrous heme-NO complex by O2 is key for catalytic cycling, but the mechanism is unclear. We utilized stopped-flow methods to study reaction of O2 with ferrous heme-NO complexes of the inducible and neuronal NOS enzymes. We found that the reaction does not involve heme-NO dissociation, but instead proceeds by a rapid, direct reaction of O2 with the ferrous heme-NO complex. This behavior is novel and may distinguish heme-thiolate enzymes like NOS from related heme proteins. PMID:19691141

  20. Metallic Recovery and Ferrous Melting Processes

    SciTech Connect

    Luis Trueba

    2004-05-30

    The effects of melting atmosphere and charge material type on the metallic and alloy recovery of ferrous charge materials were investigated in two sets of experiments (Tasks 1 and 2). In addition, thermodynamic studies were performed (Task 3) to determine the suitability of ladle treatment for the production of ductile iron using scrap charge materials high in manganese and sulfur. Task 1--In the first set of experiments, the charge materials investigated were thin steel scrap, thick steel scrap, cast iron scrap, and pig iron in the rusty and clean states. Melting atmospheres in this set of experiments were varied by melting with and without a furnace cover. In this study, it was found that neither covered melting nor melting clean (non-rusty) ferrous charge materials improved the metallic recovery over the recovery experienced with uncovered melting or rusty charge materials. However, the silicon and manganese recoveries were greater with covered melting and clean materials. Silicon and manganese in the molten iron react with oxygen dissolved in the iron from uncovered melting and oxidized iron (surface rust). Silica and manganese silicates are formed which float to the slag decreasing recoveries of silicon and manganese. Cast iron and pig iron had higher metallic recoveries than steel scrap. Carbon recovery was affected by the carbon content of the charge materials, and not by the melting conditions. Irons with higher silicon contents had higher silicon recovery than irons with lower silicon contents. Task 2--In the second set of experiments, briquetted turnings and borings were used to evaluate the effects of briquette cleanliness, carbon additions, and melting atmosphere on metallic and alloy recovery. The melting atmosphere in this set of experiments was varied by melting in air and with an argon atmosphere using the SPAL process. In this set of experiments, carbon additions to the briquettes were found to have the greatest effect on metallic and alloy recovery. The use of an argon atmosphere was also found to increase recoveries, but to a lesser extent than with carbon additions to the briquettes. Task 3--Finally, thermodynamic studies were carried out to evaluate the potential for removing manganese and sulfur from iron melts for the production of ferritic ductile iron. Thermodynamic calculations indicated that manganese and sulfur might be removed from iron melts by careful control of the temperature and slag. In laboratory tests however, it was shown that the removal of sulfur was much less successful than that indicated by the thermodynamic analyses.

  1. Pulsed laser surface hardening of ferrous alloys.

    SciTech Connect

    Xu, Z.; Reed, C. B.; Leong, K. H.; Hunter, B. V.

    1999-09-30

    A high power pulsed Nd:YAG laser and special optics were used to produce surface hardening on 1045 steel and gray cast iron by varying the process parameters. Unlike CO{sub 2} lasers, where absorptive coatings are required, the higher absorptivity of ferrous alloys at the Nd:YAG laser wavelength eliminates the necessity of applying a coating before processing. Metallurgical analysis of the treated tracks showed that very fine and hard martensitic microstructure (1045 steel) or inhomogeneous martensite (gray cast iron) were obtained without surface melting, giving maximum hardness of HRC 61 and HRC 40 for 1045 steel and gray cast iron respectively. The corresponding maximum case depths for both alloys at the above hardness are 0.6 mm. Gray cast iron was more difficult to harden without surface melting because of its lower melting temperature and a significantly longer time-at-temperature required to diffuse carbon atoms from the graphite flakes into the austenite matrix during laser heating. The thermal distortion was characterized in term of flatness changes after surface hardening.

  2. Preparation and Characterization of Cast Ferrous Metal Matrix Composites

    NASA Astrophysics Data System (ADS)

    Dash, R. R.; Chakrabarti, A. K.; Mukherjee, P. S.

    2012-02-01

    TiC/SiC reinforced cast ferrous composites have been prepared by smelting red mud30 pct charcoal briquettes in a 20-kg basic lined, single-phase direct arc furnace. Elements like silicon, aluminum, zirconium, and so on are also reduced from their respective oxides in the red mud and dissolved in the ferrous matrix. TiC/SiC particulates in the composite grow in a typical spiraling fashion.

  3. Questions and Answers on Unapproved Chelation Products

    MedlinePLUS

    ... OTC) to prevent or treat diseases. Companies are marketing unapproved OTC chelation therapy products to patients with ... 4. Why did FDA take this action? Companies marketing unapproved OTC chelation products with unsubstantiated treatment claims ...

  4. Hydroxypyridonate and hydroxypyrimidinone chelating agents

    SciTech Connect

    Raymond, Kenneth N.; Doble, Daniel M.; Sunderland, Christopher J.; Thompson, Marlon

    2005-01-25

    The present invention provides hydroxypyridinone and hydroxypyrimidone chelating agents. Also provides are Gd(III) complexes of these agents, which are useful as contrast enhancing agents for magnetic resonance imaging. The invention also provides methods of preparing the compounds of the invention, as well as methods of using the compounds in magnetic resonance imaging applications.

  5. Induction of Porphyrin Synthesis in Etiolated Bean Leaves by Chelators of Iron 12

    PubMed Central

    Duggan, Jeffrey; Gassman, Merrill

    1974-01-01

    Primary leaves of 7- to 9-day-old etiolated seedlings of Phaseolus vulgaris L. var. Red Kidney infiltrated in darkness with aqueous solutions of ?, ??-dipyridyl, o-phenanthroline, pyridine-2-aldoxime, pyridine-2-aldehyde, 8-hydroxyquinoline, or picolinic acid synthesize large amounts of magnesium protoporphyrin monomethyl ester and lesser amounts of magnesium protoporphyrin, protoporphyrin, and protochlorophyllide. Pigment formation proceeds in a linear manner for up to 21 hours after vacuum infiltration with 10 mm ?, ??-dipyridyl. Etiolated tissues of Zea mays L., Cucumis sativus L., and Pisum sativum L. respond in the same way to dipyridyl treatment. Compounds active in eliciting this response are aromatic heterocyclic nitrogenous bases which also act as bidentate chelators and form extremely stable complexes with iron; other metal ion chelators, such as ethylenediaminetetraacetic acid, salicylaldoxime, and sodium diethyldithiocarbamate, do not elicit any pigment synthesis. The ferrous, ferric, cobaltous, and zinc chelates of ?, ??-dipyridyl are similarly ineffective. If levulinic acid is supplied to etiolated bean leaves together with ?, ??-dipyridyl, porphyrin production is inhibited and ?-aminolevulinic acid accumulates in the tissue. Synthesis of porphyrins proceeds in the presence of 450 micrograms per milliliter chloramphenicol or 50 micrograms per milliliter cycloheximide with only partial diminution. We propose that heme or an iron-protein complex blocks the action of the enzyme(s) governing the synthesis of ?-aminolevulinic acid in etiolated leaves in the dark and that iron chelators antagonize this inhibition, leading to the biosynthesis of ?-aminolevulinic acid and porphyrins. PMID:16658677

  6. Natural chelating agents for radionuclide decorporation

    DOEpatents

    Premuzic, Eugene T.

    1988-01-01

    This invention relates to the preparation of new, naturally produced chelating agents as well as to the method and resulting chelates of desorbing cultures in a bioavailable form involving Pseudomonas species or other microorganisms. A preferred microorganism is Pseudomonas aeruginosa which forms multiple chelates with thorium in the range of molecular weight 100-1,000 and also forms chelates with uranium of molecular weight in the area of 100-1,000 and 1,000-2,000.

  7. Iron chelation and multiple sclerosis

    PubMed Central

    Weigel, KelseyJ.; Lynch, SharonG.; LeVine, StevenM.

    2014-01-01

    Histochemical and MRI studies have demonstrated that MS (multiple sclerosis) patients have abnormal deposition of iron in both gray and white matter structures. Data is emerging indicating that this iron could partake in pathogenesis by various mechanisms, e.g., promoting the production of reactive oxygen species and enhancing the production of proinflammatory cytokines. Iron chelation therapy could be a viable strategy to block iron-related pathological events or it can confer cellular protection by stabilizing hypoxia inducible factor 1?, a transcription factor that normally responds to hypoxic conditions. Iron chelation has been shown to protect against disease progression and/or limit iron accumulation in some neurological disorders or their experimental models. Data from studies that administered a chelator to animals with experimental autoimmune encephalomyelitis, a model of MS, support the rationale for examining this treatment approach in MS. Preliminary clinical studies have been performed in MS patients using deferoxamine. Although some side effects were observed, the large majority of patients were able to tolerate the arduous administration regimen, i.e., 68h of subcutaneous infusion, and all side effects resolved upon discontinuation of treatment. Importantly, these preliminary studies did not identify a disqualifying event for this experimental approach. More recently developed chelators, deferasirox and deferiprone, are more desirable for possible use in MS given their oral administration, and importantly, deferiprone can cross the bloodbrain barrier. However, experiences from other conditions indicate that the potential for adverse events during chelation therapy necessitates close patient monitoring and a carefully considered administration regimen. PMID:24397846

  8. Iron chelation and multiple sclerosis.

    PubMed

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

    2014-01-01

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

  9. SYNTHETIC IRON CHELATES AS SUBSTRATES OF ROOT FERRIC CHELATE REDUCTASE IN GREEN STRESSED CUCUMBER PLANTS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    While the chemistry of chelates in soils is fairly well understood, the role of the Fe3+-chelates as substrates for roots has received less attention. This work evaluated the efficacy of Fe-chelates to supply iron to mildly chlorotic plants. Fe-chelate reductase activity (FCR) and Fe in xylem sap ...

  10. Enhanced NO{sub x} removal in wet scrubbers using metal chelates. Final report, Volume 1

    SciTech Connect

    Smith, K.; Lani, B.; Berisko, D.; Schultz, C.; Carlson, W.; Benson, L.B.

    1992-12-01

    Successful pilot plant tests of simultaneous removal of S0{sub 2} and NO{sub x} in a wet lime flue gas desulfurization system were concluded in December. The tests, at up to 1.5 MW(e) capacity, were conducted by the Cincinnati Gas and Electric Company and Dravo Lime Company for the US Department of Energy at a pilot facility at the Miami Fort station of CG&E near Cincinnati, Ohio. The pilot plant scrubbed a slipstream of flue gas from Unit 7, a 530 MW coal-fired electric generating unit. Tests were conducted in three phases between April and December. The technology tested was wet scrubbing with Thiosorbic{reg_sign} magnesium-enhanced lime for S0{sub 2} removal and simultaneous NO scrubbing with ferrous EDTA, a metal chelate. Magnesium-enhanced lime-based wet scrubbing is used at 20 full-scale high-sulfur coal-fired electric generating units with a combined capacity of 8500 NW. Ferrous EDTA reacts with nitric oxide, NO, which comprises about 95% of NO{sub x} from coal-fired boilers. In this report, although not precise, NO and NO{sub x} are used interchangably. A major objective of the tests was to combine NO{sub x} removal using ferrous EDTA, a developing technology, with SO{sub 2} removal using wet lime FGD, already in wide commercial use. If successful, this could allow wide application of this NO{sub x} removal technology.

  11. Luminescent lanthanide chelates and methods of use

    DOEpatents

    Selvin, Paul R. (Berkeley, CA); Hearst, John (Berkeley, CA)

    1997-01-01

    The invention provides lanthanide chelates capable of intense luminescence. The celates comprise a lanthanide chelator covalently joined to a coumarin-like or quinolone-like sensitizer. Exemplary sensitzers include 2- or 4-quinolones, 2- or 4-coumarins, or derivatives thereof e.g. carbostyril 124 (7-amino-4-methyl-2-quinolone), coumarin 120 (7-amino-4-methyl-2-coumarin), coumarin 124 (7-amino-4-(trifluoromethyl)-2-coumarin), aminomethyltrimethylpsoralen, etc. The chelates form high affinity complexes with lanthanides, such as terbium or europium, through chelator groups, such as DTPA. The chelates may be coupled to a wide variety of compounds to create specific labels, probes, diagnostic and/or therapeutic reagents, etc. The chelates find particular use in resonance energy transfer between chelate-lanthanide complexes and another luminescent agent, often a fluorescent non-metal based resonance energy acceptor. The methods provide useful information about the structure, conformation, relative location and/or interactions of macromolecules.

  12. Some Linguistic Detail on Chelation

    NASA Astrophysics Data System (ADS)

    Haworth, Daniel T.

    1998-01-01

    The term chelate was first applied by Morgan and Drew in 1920 to describe the heterocyclic rings formed from bidentate ligands bonding to a central atom. The history of the word ch_l_ is traced from its original Greek meaning through the Latin language to its anglicized form, chela. This word has a very rich history and has been cited by both Greek (Aristotle) and Latin (Cicero, Vergil) philosophers and poets.

  13. The origin of ferrous zoning in Allende chondrule olivines

    NASA Technical Reports Server (NTRS)

    Peck, Julia A.; Wood, John A.

    1987-01-01

    Very similar major and minor element compositions are noted in the ferrous olivine occurring in chondrules at olivine grain boundaries, along cracks in olivine grains, interleaved with enstatite, and in the inner portions of exposed olivine grain surface rims; simultaneous formation by a single process is therefore suggested. The ferrous chondrule olivine probably formed by the reaction of chondrules with very hot nebular vapors over a period of several hours, followed by the condensation of residual metal vapors onto those olivine surfaces that were in direct contact with the gas as the system cooled. The ferrous chondrule olivine that occurs interleaved with enstatite in Allende does not have a composition idendical to, and is not the precursor of, matrix olivine.

  14. The ferrous-oxy complex of human aromatase

    SciTech Connect

    Grinkova, Yelena V.; Denisov, Ilia G.; Waterman, Michael R. Arase, Miharu; Kagawa, Norio; Sligar, Stephen G.

    2008-07-25

    In this communication, we document the self-assembly of heterologously expressed truncated human aromatase (CYP19) into nanometer scale phospholipids bilayers (Nanodiscs). The resulting P450 CYP19 preparation is stable and can tightly associate with the substrate androstenedione to form a nearly complete high-spin ferric protein. Ferrous CYP19 in Nanodiscs was mixed anaerobically in a rapid-scan stopped-flow with atmospheric dioxygen and the formation of the ferrous-oxy complex observed. First order decay of the oxy-complex to release superoxide and regenerate the ferric enzyme was monitored kinetically. Surprisingly, the ferrous-oxy complex of aromatase is more stable than that of hepatic CYP3A4, opening the path to precisely determine the biochemical and biophysical properties of the reaction cycle intermediates in this important human drug target.

  15. [Ferrous-manganese oxidizing bacteria from the nature water].

    PubMed

    Qin, Song-yan; Ma, Fang; Huang, Peng

    2008-06-01

    Glass slides were hanged into a canal to acquire the ferrous-manganese oxidizing bacteria settled bio-film. Two isolated methods for ferrous-manganese oxidizing bacteria with special iron-manganese oxidizing matrix from the bio-film were tested. Element component of bacteria product and sheath structure of bacteria were analyzed. With two methods, plate cultivation and the novel semi-solid in situ cultivation method, strains belong to Family Leptothrix were isolated. XRF showed that the amorphous iron and manganese were two major metal elements of the precipitation formed by one strain of Leptothrix spp.. Through the microscope observation, one strain of Family Leptothrix was determined to form branch-like structured sheath, while another strain formed spider web-like structured sheath. Those isolated bacteria provide model strains for future testing of FISH probe and PCR primer of ferrous-manganese oxidizing bacteria. PMID:18763517

  16. Ascorbic acid enhanced activation of oxygen by ferrous iron: A case of aerobic degradation of rhodamine B.

    PubMed

    Hou, Xiaojing; Shen, Wenjuan; Huang, Xiaopeng; Ai, Zhihui; Zhang, Lizhi

    2016-05-01

    Molecular oxygen activation by ferrous ions (Fe(II)) in aqueous solution could generate reactive oxygen species (ROS) with high oxidation potential via reaction between Fe(II) and oxygen molecules (Fe(II)/air), however, ROS yielded in the Fe(II)/air process is insufficient for removal of organic pollutants due to the irreversible ferric ions (Fe(III)) accumulation. In this study, we demonstrate that ascorbic acid (AA) could enhance ROS generation via oxygen activation by ferrous irons (AA/Fe(II)/air) and thus improve the degradation of rhodamine (RhB) significantly. It was found that the first-order aerobic degradation rate of RhB in the AA/Fe(II)/air process in the presence of ascorbic acid is more than 4 times that of the Fe(II)/Air system without adding ascorbic acid. The presence of ascorbic acid could relieve the accumulation of Fe(III) by reductive accelerating the Fe(III)/Fe(II) cycles, as well as lower the redox potential of Fe(III)/Fe(II) through chelating effect, leading to enhanced ROS generation for promoting RhB degradation. This study not only sheds light on the effect of ascorbic acid on aerobic Fe(II) oxidation, but also provides a green method for effective remediation of organic pollutants. PMID:26808244

  17. Phosphonated chelates for nuclear imaging.

    PubMed

    Abada, Sabah; Lecointre, Alexandre; Christine, Cline; Ehret-Sabatier, Laurence; Saupe, Falk; Orend, Gertraud; Brasse, David; Ouadi, Ali; Hussenet, Thomas; Laquerrire, Patrice; Elhabiri, Mourad; Charbonnire, Loc J

    2014-12-21

    A series of bis-, tris- and tetra-phosphonated pyridine ligands is presented. In view of their potential use as chelates for radiopharmaceutical applications, the physico-chemical properties of the ligands and of their Co(II), Ni(II), Cu(II), and Zn(II) complexes were studied by means of potentiometry and UV-Vis absorption spectroscopy. The pKa values of the ligands and of the complexes, as well as the stability constants for the formation of the complexes, are presented. The kinetic aspects of the formation of Cu(II) complexes and of their dissociation in acidic media were studied by means of stopped flow experiments, and the stability of the Cu(II) complex toward reduction to Cu(I) was investigated by cyclic voltammetry and by titration with different reducing agents. The different thermodynamic and kinetic aspects of the polyphosphonated ligands were compared with regard to the impact of the number of phosphonic acid functions. Considering the very promising properties for complexation, preliminary SPECT/CT imaging experiments were carried out on mice with (99m)Tc using the bis- and tetra-phosphonated ligands L(2) and L(1). Finally, a bifunctional version of chelate L(1), L*, was used to label MTn12, a rat monoclonal antibody with both specificity and relatively high affinity for murine tenascin-C. The labeling was monitored by MALDI/MS spectrometry and the affinity of the labeled antibody was checked by immunostaining experiments. After chelation with (99m)Tc, the (99m)Tc-L*-MTn12 antibody was injected into a transgenic mouse with breast cancer and the biodistribution of the labeled antibody was followed by SPECT/CT imaging. PMID:25338628

  18. Synthesis and thermodynamic evaluation of mixed hexadentate linear iron chelators containing hydroxypyridinone and terephthalamide units.

    PubMed

    Abergel, Rebecca J; Raymond, Kenneth N

    2006-05-01

    A series of new linear iron chelators containing hydroxypyridinone and terephthalamide (TAMmeg) moieties have been prepared. All are hexadentate ligands composed of a systematically varied combination of methyl-3,2-hydroxypyridinone and 2,3-dihydroxyterephthalamide binding units; most are based on a spermidine scaffold, but one incorporates the bifunctional 2,3-dihydroxyterephthalamide unit as an integral part of the backbone. Protonation and ferric iron complex formation constants have been determined from solution thermodynamic studies, giving log beta(110) values of 25.7, 30.7, 36.3, 43.8, and 45.0, respectively. The ferric complexes display reversible reduction potentials from -276 to -1032 mV (measured relative to the normal hydrogen electrode) in alkaline solution. The incremental replacement of hydroxypyridinone units by terephthalamide binding groups progressively reduces the ligand acidity, markedly increases the iron-chelate stability, and improves the selectivity for the ferric ion over the ferrous ion. While the majority of iron chelators forming very stable ferric complexes are based on a tripodal backbone such as TREN, the ferric 5-LIO(TAMmeg)(2)(TAM) complex, despite its nontripodal scaffold, is one of the most stable iron complexes yet reported. Moreover, the high affinity for the ferric ion of the discussed linear ligands strongly correlates with their ability to remove iron in vivo. PMID:16634594

  19. 21 CFR 184.1307c - Ferrous citrate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Ferrous citrate. 184.1307c Section 184.1307c Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) DIRECT FOOD SUBSTANCES AFFIRMED AS GENERALLY RECOGNIZED AS SAFE Listing of Specific Substances Affirmed as GRAS...

  20. 21 CFR 184.1307c - Ferrous citrate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Ferrous citrate. 184.1307c Section 184.1307c Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) DIRECT FOOD SUBSTANCES AFFIRMED AS GENERALLY RECOGNIZED AS SAFE Listing of Specific Substances Affirmed as GRAS...

  1. 21 CFR 184.1307c - Ferrous citrate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Ferrous citrate. 184.1307c Section 184.1307c Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) DIRECT FOOD SUBSTANCES AFFIRMED AS GENERALLY RECOGNIZED AS SAFE Listing of Specific Substances Affirmed as GRAS...

  2. 21 CFR 184.1307c - Ferrous citrate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ferrous citrate. 184.1307c Section 184.1307c Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) DIRECT FOOD SUBSTANCES AFFIRMED AS GENERALLY RECOGNIZED AS SAFE Listing of Specific Substances Affirmed as GRAS...

  3. 21 CFR 184.1307a - Ferrous ascorbate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ferrous ascorbate. 184.1307a Section 184.1307a Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) DIRECT FOOD SUBSTANCES AFFIRMED AS GENERALLY RECOGNIZED AS SAFE Listing of Specific Substances Affirmed as GRAS...

  4. Method for the preparation of ferrous low carbon porous material

    SciTech Connect

    Miller, Curtis Jack

    2014-05-27

    A method for preparing a porous metal article using a powder metallurgy forming process is provided which eliminates the conventional steps associated with removing residual carbon. The method uses a feedstock that includes a ferrous metal powder and a polycarbonate binder. The polycarbonate binder can be removed by thermal decomposition after the metal article is formed without leaving a carbon residue.

  5. Cu(II) - Catalyzed Hydrazine Reduction of Ferrous Nitrate

    SciTech Connect

    Karraker, D.G.

    2001-10-15

    This report discusses the results of a study of catalyzed hydrazine reduction of ferrous nitrate. It is apparent that there is a substantial reaction between hydrazine and nitrate ion (or nitric acid) to produce HN3 during both the reduction of Fe(III) and during storage at room temperature.

  6. LIMESTONE AND LIME NEUTRALIZATION OF FERROUS IRON ACID MINE DRAINAGE

    EPA Science Inventory

    The U.S. Environmental Protection Agency conducted a 2-yr study on hydrated lime and rock-dust limestone neutralization of acid mine drainage containing ferrous iron at the EPA Crown Mine Drainage Control Field Site near Rivesville, West Virginia. The study investigated optimizat...

  7. 40 CFR 464.30 - Applicability; description of the ferrous casting subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... ferrous casting subcategory. 464.30 Section 464.30 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) METAL MOLDING AND CASTING POINT SOURCE CATEGORY Ferrous Casting Subcategory 464.30 Applicability; description of the ferrous casting...

  8. 40 CFR 464.30 - Applicability; description of the ferrous casting subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... ferrous casting subcategory. 464.30 Section 464.30 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS METAL MOLDING AND CASTING POINT SOURCE CATEGORY Ferrous Casting Subcategory 464.30 Applicability; description of the ferrous casting subcategory....

  9. 40 CFR 464.30 - Applicability; description of the ferrous casting subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... ferrous casting subcategory. 464.30 Section 464.30 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) METAL MOLDING AND CASTING POINT SOURCE CATEGORY Ferrous Casting Subcategory 464.30 Applicability; description of the ferrous casting...

  10. 40 CFR 464.30 - Applicability; description of the ferrous casting subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... ferrous casting subcategory. 464.30 Section 464.30 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS METAL MOLDING AND CASTING POINT SOURCE CATEGORY Ferrous Casting Subcategory 464.30 Applicability; description of the ferrous casting subcategory....

  11. 40 CFR 464.30 - Applicability; description of the ferrous casting subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... ferrous casting subcategory. 464.30 Section 464.30 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) METAL MOLDING AND CASTING POINT SOURCE CATEGORY Ferrous Casting Subcategory 464.30 Applicability; description of the ferrous casting...

  12. DETERMINATION OF THE RATES AND PRODUCTS OF FERROUS IRON OXIDATION IN ARSENIC-CONTAMINATED POND WATER.

    EPA Science Inventory

    Dissolved ferrous iron and arsenic in the presence of insufficient oxygenated ground water is released into a pond. When the mixing of ferrous iron and oxygenated water within the pond occurs, the ferrous iron is oxidized and precipitated as an iron oxide. Groups of experiments...

  13. 40 CFR 180.1230 - Ferrous sulfate; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Ferrous sulfate; exemption from the... Exemptions From Tolerances 180.1230 Ferrous sulfate; exemption from the requirement of a tolerance. An exemption from the requirement of a tolerance is established for residues of ferrous sulfate....

  14. 40 CFR 180.1230 - Ferrous sulfate; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Ferrous sulfate; exemption from the... Exemptions From Tolerances 180.1230 Ferrous sulfate; exemption from the requirement of a tolerance. An exemption from the requirement of a tolerance is established for residues of ferrous sulfate....

  15. 40 CFR 180.1230 - Ferrous sulfate; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Ferrous sulfate; exemption from the... Exemptions From Tolerances 180.1230 Ferrous sulfate; exemption from the requirement of a tolerance. An exemption from the requirement of a tolerance is established for residues of ferrous sulfate....

  16. 40 CFR 180.1230 - Ferrous sulfate; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Ferrous sulfate; exemption from the... Exemptions From Tolerances 180.1230 Ferrous sulfate; exemption from the requirement of a tolerance. An exemption from the requirement of a tolerance is established for residues of ferrous sulfate....

  17. 40 CFR 180.1230 - Ferrous sulfate; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Ferrous sulfate; exemption from the... Exemptions From Tolerances 180.1230 Ferrous sulfate; exemption from the requirement of a tolerance. An exemption from the requirement of a tolerance is established for residues of ferrous sulfate....

  18. Characterization of antibody-chelator conjugates: Determination of chelator content by terbium fluorescence titration

    SciTech Connect

    Brandt, K.D.; Schnobrich, K.E.; Johnson, D.K. )

    1991-01-01

    Fluorescence titrations were performed by adding varying mole ratios of terbium(III) to antibody conjugates formed by benzyl isothiocyanate derivatives of three different polyaminopolycarboxylate chelators (NTA, EDTA, and DTPA) and the results compared to values for average chelator content obtained by cobalt-57 binding assays. For two different murine monoclonal antibodies, the average chelator content obtained by terbium fluorescence titration correlated closely with that measured by the cobalt-57 binding assay. It is concluded that lanthanide fluorescence titrations provide a useful alternative to radiometal binding assays for the determination of chelator content in protein-chelator conjugates.

  19. Chelators in biomedical research: a review.

    PubMed

    Mbati, P A

    1996-06-01

    Chelators have been used in many aspects of biomedical research, from water softening to antidotes for heavy metal ion intoxication. At present, novel therapeutic regimens have been developed against psychiatric disorders, viral, and protozoal infections. Many clinical trials and biomedical research continues in the use of chelating agents in solving various medical problems. PMID:8840593

  20. Natural chelating agents for radionuclide decorporation

    DOEpatents

    Premuzic, E.T.

    1985-06-11

    This invention relates to the production of metal-binding compounds useful for the therapy of heavy metal poisoning, for biological mining and for decorporation of radionuclides. The present invention deals with an orderly and effective method of producing new therapeutically effective chelating agents. This method uses challenge biosynthesis for the production of chelating agents that are specific for a particular metal. In this approach, the desired chelating agents are prepared from microorganisms challenged by the metal that the chelating agent is designed to detoxify. This challenge induces the formation of specific or highly selective chelating agents. The present invention involves the use of the challenge biosynthetic method to produce new complexing/chelating agents that are therapeutically useful to detoxify uranium, plutonium, thorium and other toxic metals. The Pseudomonas aeruginosa family of organisms is the referred family of microorganisms to be used in the present invention to produce the new chelating agent because this family is known to elaborate strains resistant to toxic metals.

  1. Complexation of nicotinamide adenine dinucleotide with ferric and ferrous ions.

    PubMed

    Lvovich, V; Scheeline, A

    1995-06-20

    Motivated by the observed influence of stainless steel and ferric and ferrous ions on the behavior of the peroxidase/oxidase oscillator, the mechanism and kinetics of interaction of 1,4-dihydronicotinamide adenine dinucleotide (NADH) with iron ions in 0.1 M acetic acid/sodium acetate buffer with pH 5.1 and with the solution/stainless steel interface were extensively studied. The character of a possible mutual influence of NADH/acetate buffer solution and Type 316 stainless steel has been investigated. We also suggest the mechanism of stainless steel corrosion inhibition by NADH. It was determined that fast complexation of ferric and ferrous ions with NADH occurred with rate constant kcompl = 4.0 x 10(9) +/- 0.2 x 10(9) M-1 s-1. The composition of the product complex is [Fe-(NADH)2] for both Fe2+ and Fe3+. A previously unreported complex of ferrous ion and NADH was discovered, determined, and separately investigated. Kinetic and equilibrium constants for reactions of iron ions-NADH complexation and following redox processes of the complex decomposition were determined from spectrophotometric and electrochemical experiments. PMID:7793967

  2. Enhanced NO{sub x} removal in wet scrubbers using metal chelates. Final report, Volume 2

    SciTech Connect

    1992-12-01

    Successful pilot plant tests of simultaneous removal of SO{sub 2} and NO{sub x} in a wet lime flue gas desulfurization system were concluded in December. The test, at up to 1.5 MW(e) capacity, were conducted by the Cincinnati Gas and Electric Company and Dravo Lime Company for the US Department of Energy at a pilot plant facility at the Miami Fort station of CG&E near Cincinnati, Ohio. The pilot plant scrubbed a slipstream of flue gas from Unit 7 a 530 MW coal-fired electric generating unit. Tests were conducted in three phases between April and December. The technology tested was wet scrubbing with Thiosorbic{reg_sign} magnesium-enhanced lime for SO{sub 2} removal and simultaneous NO scrubbing with ferrous EDTA, a metal chelate. Magnesium-enhanced lime-based wet scrubbing is used at 20 full-scale high-sulfur coal-fired electric generating units with a combined capacity of 8500 MW. Ferrous EDTA reacts with nitric oxide, NO, which comprises about 96% of NO{sub x} from coal-fired boilers. In this report, although not precise, NO and NO{sub x} are used interchangeably. A major objective of the tests was to combine NO{sub x} removal using ferrous EDTA, a developing technology, with SO{sub 2} removal using wet lime FGD, already in wide commercial use. If successful, this could allow wide application of this NO{sub x} removal technology. Volume 2 covers: description and results of NO{sub x} removal tests; and description and results of waste characterization studies.

  3. [Influence of ionizing radiation, application of iron ions and their chelate complexes on the oxidative status of blood serum of rats].

    PubMed

    Riabchenko, N I; Ivannik, B P; Riabchenko, V I; Dzikovskaia, L A

    2011-01-01

    Influence of ionizing radiation, ions of iron and their chelate complexes on the oxidative status of blood serum of rats has been investigated. Animals were irradiated by gamma-rays 60Co at a dose of 4 Gy. Ions of iron and iron chelates with nitrilotriacetic acid and citric acid were introduced into animals intra-abdominally at a doze of 10 mg of iron on 1 kg of body weight. The oxidative status of blood serum was determined according to the estimated content of oxidizing peroxide equivalents which oxidize ferrous iron in ferric iron with the subsequent estimation of ferric iron by means of xylenol orange. We also estimated the total content of iron in blood serum using ferrozine as an indicator. The oxidative status was defined 24 and 96 hours after irradiation and 2 hours after introduction of iron ions and their chelates. The research conducted has shown that the concentration of oxidizing peroxide equivalents in serum and the total iron concentration increase 1.47 times and 1.63 times correspondingly 24 hours after irradiation. The increase in the content of oxidizing peroxide equivalents and iron owing to Fenton's reaction can lead to the appearance of OH* radical and raise the level of damage of nuclear and membrane structures in irradiated cells. 2 hours after introduction of iron ions and their chelates, the content of oxidizing peroxide equivalents increased in the blood serum of irradiated and non-irradiated rats, and the maximum effect was observed when introducing ferrous iron and its chelate with citric acid. PMID:21674949

  4. Iron-chelating activity of chickpea protein hydrolysate peptides.

    PubMed

    Torres-Fuentes, Cristina; Alaiz, Manuel; Vioque, Javier

    2012-10-01

    Chickpea-chelating peptides were purified and analysed for their iron-chelating activity. These peptides were purified after affinity and gel filtration chromatography from a chickpea protein hydrolysate produced with pepsin and pancreatin. Iron-chelating activity was higher in purified peptide fractions than in the original hydrolysate. Histidine contents were positively correlated with the iron-chelating activity. Hence fractions with histidine contents above 20% showed the highest chelating activity. These results show that iron-chelating peptides are generated after chickpea protein hydrolysis with pepsin plus pancreatin. These peptides, through metal chelation, may increase iron solubility and bioavailability and improve iron absorption. PMID:25005984

  5. Fluid extraction using carbon dioxide and organophosphorus chelating agents

    DOEpatents

    Smart, Neil G.; Wai, Chien M.; Lin, Yuehe; Kwang, Yak Hwa

    1998-01-01

    Methods for extracting metalloid and metal species from a solid or liquid material by exposing the material to a fluid solvent, particularly supercritical CO.sub.2, and a chelating agent are described. The chelating agent forms a chelate with the species, the chelate being soluble in the fluid to allow removal of the species from the material. In preferred embodiments the extraction solvent is supercritical CO.sub.2 and the chelating agent comprises an organophosphorous chelating agent, particularly sulfur-containing organophosphorous chelating agents, including mixtures of chelating agents. Examples of chelating agents include monothiophosphinic acid, di-thiophosphinic acid, phosphine sulfite, phosphorothioic acid, and mixtures thereof. The method provides an environmentally benign process for removing metal and metalloids from industrial waste solutions, particularly acidic solutions. Both the chelate and the supercritical fluid can be regenerated and the contaminant species recovered to provide an economic, efficient process.

  6. Fluid extraction using carbon dioxide and organophosphorus chelating agents

    DOEpatents

    Smart, N.G.; Wai, C.M.; Lin, Y.; Kwang, Y.H.

    1998-11-24

    Methods for extracting metalloid and metal species from a solid or liquid material by exposing the material to a fluid solvent, particularly supercritical CO{sub 2}, and a chelating agent are described. The chelating agent forms a chelate with the species, the chelate being soluble in the fluid to allow removal of the species from the material. In preferred embodiments the extraction solvent is supercritical CO{sub 2} and the chelating agent comprises an organophosphorous chelating agent, particularly sulfur-containing organophosphorous chelating agents, including mixtures of chelating agents. Examples of chelating agents include monothiophosphinic acid, di-thiophosphinic acid, phosphine sulfite, phosphorothioic acid, and mixtures thereof. The method provides an environmentally benign process for removing metal and metalloids from industrial waste solutions, particularly acidic solutions. Both the chelate and the supercritical fluid can be regenerated and the contaminant species recovered to provide an economic, efficient process. 1 fig.

  7. Iron Reverses Impermeable Chelator Inhibition of DNA Synthesis in CCl39 Cells

    NASA Astrophysics Data System (ADS)

    Alcain, Francisco J.; Low, Hans; Crane, Frederick L.

    1994-08-01

    Treatment of Chinese hamster lung fibro-blasts (CCl 39 cells) with the impermeable iron(II) chelator bathophenanthroline disulfonate (BPS) inhibits DNA synthesis when cell growth is initiated with growth factors including epidermal growth factor plus insulin, thrombin, or ceruloplasmin, but not with 10% fetal calf serum. The BPS treatment inhibits transplasma membrane electron transport. The treatment leads to release of iron from the cells as determined by BPS iron(II) complex formation over 90 min. Growth factor stimulation of DNA synthesis and electron transport are restored by addition of di- or trivalent iron to the cells in the form of ferric ammonium citrate, ferrous ammonium sulfate, or diferric transferrin. The effect with BPS differs from the inhibition of growth by hydroxyurea, which acts on the ribonucleotide reductase, or diethylenetriaminepentaacetic acid, which is another impermeable chelating agent, in that these agents inhibit growth in 10% fetal calf serum. The BPS effect is consistent with removal of iron from a site on the cell surface that controls DNA synthesis.

  8. Overview of Lightweight Ferrous Materials: Strategies and Promises

    NASA Astrophysics Data System (ADS)

    Rana, Radhakanta; Lahaye, Chris; Ray, Ranjit Kumar

    2014-09-01

    Reducing the density of steels is a novel approach for weight reduction of automobiles to improve fuel efficiency. In this overview article, strategies for the development of lightweight steels are presented with a focus on bulk ferrous alloys. The metallurgical principles of these steels and their mechanical properties of relevance to automotive applications are discussed. Some of the engineering aspects highlighting the possible problems related to mass production of these steels are also considered. Application prospects of these steels vis--vis standard automotive steels are shown.

  9. Overview of Lightweight Ferrous Materials: Strategies and Promises

    NASA Astrophysics Data System (ADS)

    Rana, Radhakanta; Lahaye, Chris; Ray, Ranjit Kumar

    2014-08-01

    Reducing the density of steels is a novel approach for weight reduction of automobiles to improve fuel efficiency. In this overview article, strategies for the development of lightweight steels are presented with a focus on bulk ferrous alloys. The metallurgical principles of these steels and their mechanical properties of relevance to automotive applications are discussed. Some of the engineering aspects highlighting the possible problems related to mass production of these steels are also considered. Application prospects of these steels vis--vis standard automotive steels are shown.

  10. Copper Chelation in Alzheimer's Disease Protein

    NASA Astrophysics Data System (ADS)

    Rose, Frisco; Hodak, Miroslav; Bernholc, Jerry

    2013-03-01

    Alzheimer's disease (AD) is a neurodegenerative disorder affecting millions of people in the U.S. AD is primarily characterized at the cellular level by densely tangled fibrils of amyloid- ? protein. These protein clusters have been found in association with elevated levels of multiple transition metals, with copper being the most egregious. Interestingly, metal chelation has shown promise in attenuating the symptoms of AD in recent clinical studies. We investigate this process by constructing an atomistic model of the amyloid- ?-copper complex and profile the energetic viability in each of its subsequent disassociation stages. Our results indicate that five energetic barriers must be overcome for full metal chelation. The energy barriers are biologically viable in the presence water mediated bond and proton transfer between the metal and the protein. We model the chelation reaction using a consecutive path nudged elastic band method implemented in our ab initio real-space multi-grid code to obtain a viable sequence. This reaction model details a physically consistent explanation of the chelation process that could lead to the discovery of more effective chelation agents in the treatment of AD.

  11. Iron (FeII) Chelation, Ferric Reducing Antioxidant Power, and Immune Modulating Potential of Arisaema jacquemontii (Himalayan Cobra Lily)

    PubMed Central

    Sudan, Rasleen; Bhagat, Madhulika; Singh, Jasvinder; Koul, Anupurna

    2014-01-01

    This study explored the antioxidant and immunomodulatory potential of ethnomedicinally valuable species, namely, Arisaema jacquemontii of north-western Himalayan region. The tubers, leaves, and fruits of this plant were subjected to extraction using different solvents. In vitro antioxidant studies were performed in terms of chelation power on ferrous ions and FRAP assay. The crude methanol extract of leaves was found to harbour better chelating capacity (58% at 100 μg/mL) and reducing power (FRAP value 1085.4 ± 0.11 μMFe3+/g dry wt.) than all the other extracts. The crude methanol extract was thus further partitioned with solvents to yield five fractions. Antioxidant study of fractions suggested that the methanol fraction possessed significant chelation capacity (49.7% at 100 μg/mL) and reducing power with FRAP value of 1435.4 μM/g dry wt. The fractions were also studied for immune modulating potential where it was observed that hexane fraction had significant suppressive effect on mitogen induced T-cell and B-cell proliferation and remarkable stimulating effect on humoral response by 141% and on DTH response by 168% in immune suppressed mice as compared to the controls. Therefore, it can be concluded that A. jacquemontii leaves hold considerable antioxidant and immunomodulating potential and they can be explored further for the identification of their chemical composition for a better understanding of their biological activities. PMID:24895548

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

    PubMed

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

    2014-01-01

    To better understand the mechanism of low-iron stress tolerance in Malus xiaojinensis, the differences in physiological parameters and gene expression between an iron deficiency-sensitive species, Malus baccata, and an iron deficiency-tolerant species, M. xiaojinensis were investigated under low-iron (4 ?M Fe) conditions. Under iron sufficient conditions, the expressions of iron uptake- and transport-related genes, i.e. FIT1, IRT1, CS1, FRD3 and NRMAP1, and the immanent leaf and root active iron contents were higher in M. xiaojinensis than those in M. baccata. However, on the first three days of low iron stress, the rhizospheric pH decreased and the root ferric chelate reductase (FCR) activity and the expression of ferrous uptake- and iron transport-related genes in the roots increased significantly only in M. xiaojinensis. Leaf chlorosis occurred on the 3rd and the 9th day after low-iron treatment in M. baccata and M. xiaojinensis, respectively. The expression of iron relocalization-related genes, such as NAS1, FRD3 and NRMAP3, increased after the 5th or 6th day of low iron stress in leaves of M. xiaojinensis, whereas the expression of NAS1, FRD3 and NRMAP3 in the leaves of M. baccata increased immediately after the onset of low iron treatment. Conclusively, the relative high active iron contents caused by the immanently active root ferrous uptake and the increased root ferrous uptake in response to low iron stress were the dominant mechanisms for the tolerance to iron deficiency in M. xiaojinensis. PMID:24268163

  13. Tryptophan-to-heme electron transfer in ferrous myoglobins

    PubMed Central

    Monni, Roberto; Al Haddad, Andr; van Mourik, Frank; Aubck, Gerald; Chergui, Majed

    2015-01-01

    It was recently demonstrated that in ferric myoglobins (Mb) the fluorescence quenching of the photoexcited tryptophan 14 (*Trp14) residue is in part due to an electron transfer to the heme porphyrin (porph), turning it to the ferrous state. However, the invariance of *Trp decay times in ferric and ferrous Mbs raises the question as to whether electron transfer may also be operative in the latter. Using UV pump/visible probe transient absorption, we show that this is indeed the case for deoxy-Mb. We observe that the reduction generates (with a yield of about 30%) a low-valence Feporphyrin ? [FeII(porph??)] -anion radical, which we observe for the first time to our knowledge under physiological conditions. We suggest that the pathway for the electron transfer proceeds via the leucine 69 (Leu69) and valine 68 (Val68) residues. The results on ferric Mbs and the present ones highlight the generality of Trpporphyrin electron transfer in heme proteins. PMID:25902517

  14. Analyzing the International Exergy Flow Network of Ferrous Metal Ores

    PubMed Central

    Qi, Hai; An, Haizhong; Hao, Xiaoqing; Zhong, Weiqiong; Zhang, Yanbing

    2014-01-01

    This paper employs an un-weighted and weighted exergy network to study the properties of ferrous metal ores in countries worldwide and their evolution from 2002 to 2012. We find that there are few countries controlling most of the ferrous metal ore exports in terms of exergy and that the entire exergy flow network is becoming more heterogeneous though the addition of new nodes. The increasing of the average clustering coefficient indicates that the formation of an international exergy flow system and regional integration is improving. When we contrast the average out strength of exergy and the average out strength of currency, we find both similarities and differences. Prices are affected largely by human factors; thus, the growth rate of the average out strength of currency has fluctuated acutely in the eleven years from 2002 to 2012. Exergy is defined as the maximum work that can be extracted from a system and can reflect the true cost in the world, and this parameter fluctuates much less. Performing an analysis based on the two aspects of exergy and currency, we find that the network is becoming uneven. PMID:25188407

  15. Analyzing the international exergy flow network of ferrous metal ores.

    PubMed

    Qi, Hai; An, Haizhong; Hao, Xiaoqing; Zhong, Weiqiong; Zhang, Yanbing

    2014-01-01

    This paper employs an un-weighted and weighted exergy network to study the properties of ferrous metal ores in countries worldwide and their evolution from 2002 to 2012. We find that there are few countries controlling most of the ferrous metal ore exports in terms of exergy and that the entire exergy flow network is becoming more heterogeneous though the addition of new nodes. The increasing of the average clustering coefficient indicates that the formation of an international exergy flow system and regional integration is improving. When we contrast the average out strength of exergy and the average out strength of currency, we find both similarities and differences. Prices are affected largely by human factors; thus, the growth rate of the average out strength of currency has fluctuated acutely in the eleven years from 2002 to 2012. Exergy is defined as the maximum work that can be extracted from a system and can reflect the true cost in the world, and this parameter fluctuates much less. Performing an analysis based on the two aspects of exergy and currency, we find that the network is becoming uneven. PMID:25188407

  16. Combined SO{sub 2}/NO{sub x} control using ferrous{center_dot}EDTA and a secondary additive in a lime-based aqueous scrubber system

    SciTech Connect

    Mendelsohn, M.H.; Livengood, C.D.; Harkness, J.B.L.

    1991-12-01

    Integration of NO{sub x} control into existing flue-gas desulfurization (FGD) systems addresses site-specific control requirements while minimizing retrofit difficulties. Argonne has studied the use of the metal-chelate additives, such as ferrous{center_dot}EDTA in various wet FGD chemistries, to promote combined SO{sub 2}/NO{sub x} scrubbing. A major process problem is oxidation of the iron to the ferric species, leading to a significant decrease in NO{sub x}-removal capability. Argonne discovered a class of organic compounds that, when used with ferrous{center_dot}EDTA in a sodium carbonate chemistry, could maintain high levels of NO{sub x} removal. However, those antioxidant/reducing agents are not effective in a lime-based chemistry, and a broader investigation of antioxidants was initiated. This paper discusses results of that investigation, which found a practical antioxidant/reducing agent capable of maintaining NO{sub x} removals of about 50% (compared with about 15% without the agent) in a lime-based FGD chemistry with FE(II){center_dot}EDTA. 5 refs., 10 figs.

  17. Method and apparatus for back-extracting metal chelates

    DOEpatents

    Wai, C.M.; Smart, N.G.; Lin, Y.

    1998-08-11

    A method is described for extracting metal and metalloid species from a solid or liquid substrate using a supercritical fluid solvent containing one or more chelating agents followed by back-extracting the metal and metalloid species from the metal and metalloid chelates formed thereby. The back-extraction acidic solution is performed utilizing an acidic solution. Upon sufficient exposure of the metal and metalloid chelates to the acidic solution, the metal and metalloid species are released from the chelates into the acid solution, while the chelating agent remains in the supercritical fluid solvent. The chelating agent is thereby regenerated and the metal and metalloid species recovered. 3 figs.

  18. Method and apparatus for back-extracting metal chelates

    DOEpatents

    Wai, Chien M. (Moscow, IA); Smart, Neil G. (Moscow, IA); Lin, Yuehe (Moscow, IA)

    1998-01-01

    A method of extracting metal and metalloid species from a solid or liquid substrate using a supercritical fluid solvent containing one or more chelating agents followed by back-extracting the metal and metalloid species from the metal and metalloid chelates formed thereby. The back-extraction acidic solution is performed utilizing an acidic solution. Upon sufficient exposure of the metal and metalloid chelates to the acidic solution, the metal and metalloid species are released from the chelates into the acid solution, while the chelating agent remains in the supercritical fluid solvent. The chelating agent is thereby regenerated and the metal and metalloid species recovered.

  19. Trypanotoxic activity of thiosemicarbazone iron chelators.

    PubMed

    Ellis, Samuel; Sexton, Darren W; Steverding, Dietmar

    2015-03-01

    Only a few drugs are available for treating sleeping sickness and nagana disease; parasitic infections caused by protozoans of the genus Trypanosoma in sub-Saharan Africa. There is an urgent need for the development of new medicines for chemotherapy of these devastating diseases. In this study, three newly designed thiosemicarbazone iron chelators, TSC24, Dp44mT and 3-AP, were tested for in vitro activity against bloodstream forms of Trypanosoma brucei and human leukaemia HL-60 cells. In addition to their iron chelating properties, TSC24 and Dp44mT inhibit topoisomerase II? while 3-AP inactivates ribonucleotide reductase. All three compounds exhibited anti-trypanosomal activity, with minimum inhibitory concentration (MIC) values ranging between 1 and 100?M and 50% growth inhibition (GI50) values of around 250?nM. Although the compounds did not kill HL-60 cells (MIC values >100?M), TSC24 and Dp44mT displayed considerable cytotoxicity based on their GI50 values. Iron supplementation partly reversed the trypanotoxic and cytotoxic activity of TSC24 and Dp44mT but not of 3-AP. This finding suggests possible synergy between the iron chelating and topoisomerase II? inhibiting activity of the compounds. However, further investigation using separate agents, the iron chelator deferoxamine and the topoisomerase II inhibitor epirubicin, did not support any synergy for the interaction of iron chelation and topoisomerase II inhibition. Furthermore, TSC24 was shown to induce DNA degradation in bloodstream forms of T.brucei indicating that the mechanism of trypanotoxic activity of the compound is topoisomerase II independent. In conclusion, the data support further investigation of thiosemicarbazone iron chelators with dual activity as lead compounds for anti-trypanosomal drug development. PMID:25595343

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

    SciTech Connect

    Piwonka, T.S.

    1996-01-01

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

  1. 76 FR 9810 - Agency Information Collection Activities: Comment Request for the Ferrous Metals Surveys (17 Forms)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-22

    ... Geological Survey Agency Information Collection Activities: Comment Request for the Ferrous Metals Surveys... to supply the USGS with domestic consumption data of 13 ores, concentrates, metals, and ferroalloys... OMB Control Number: 1028-0068. Form Number: Various (17 forms). Title: Ferrous Metals Surveys. Type...

  2. Ferrous versus ferric oral iron formulations for the treatment of iron deficiency: a clinical overview.

    PubMed

    Santiago, Palacios

    2012-01-01

    Iron deficiency anaemia represents a major public health problem, particularly in infants, young children, pregnant women, and females with heavy menses. Oral iron supplementation is a cheap, safe, and effective means of increasing haemoglobin levels and restoring iron stores to prevent and correct iron deficiency. Many preparations are available, varying widely in dosage, formulation (quick or prolonged release), and chemical state (ferrous or ferric form). The debate over the advantages of ferrous versus ferric formulations is ongoing. In this literature review, the tolerability and efficacy of ferrous versus ferric iron formulations are evaluated. We focused on studies comparing ferrous sulphate preparations with ferric iron polymaltose complex preparations, the two predominant forms of iron used. Current data show that slow-release ferrous sulphate preparations remain the established and standard treatment of iron deficiency, irrespective of the indication, given their good bioavailability, efficacy, and acceptable tolerability demonstrated in several large clinical studies. PMID:22654638

  3. EDTA chelation therapy in chronic degenerative disease.

    PubMed

    Olszewer, E; Carter, J P

    1988-09-01

    A retrospective analysis of treatment results from 2870 patients, with various chronic degenerative and age-associated diseases, who were treated with di-sodium magnesium EDTA chelation therapy, suggests that the case against EDTA Chelation Therapy should be re-opened. Using qualitative but never-the-less standardized criteria for improvement, our analysis shows that EDTA Chelation Therapy resulted in "marked" improvement in 76.89% and "good" improvement in 16.56% of patients with ischemic heart disease; also, "marked" improvement in 91% and "good" improvement in 7.6% of patients with peripheral vascular disease and intermittent claudication. In a group of patients with cerebro-vascular and other degenerative cerebral diseases, 24% had "marked" improvement, and 30% had "good" improvement. Of four patients with scleroderma, three had "marked" improvement and one had "good" improvement. Seventy-five percent of all of the patients had "marked" improvement in "geriatric symptomatology of vascular origin". The authors recommend renewed study of EDTA Chelation Therapy. The possibility of a "tomato effect", i.e., a drug which works, but the majority of physicians believe that it doesn't work, needs to be ruled out. A favorable climate needs to be created, in which FDA-approved studies of its usefulness in treating peripheral vascular disease can take place. PMID:3144646

  4. Deferitazole, a new orally active iron chelator.

    PubMed

    Hider, Robert C; Kong, Xiaole; Abbate, Vincenzo; Harland, Rachel; Conlon, Kelly; Luker, Tim

    2015-03-21

    Following a systematic search of desferrithiocin analogs, a polyether derivative, deferitazole (formerly FBS0701), has entered into phase 1 and 2 clinical trials with promising biological properties. However, until now, detailed physicochemical properties of this chelator have not been reported. The compound displays a high affinity and selectivity for iron(III) as demonstrated by the log??2 = 33.39 0.03 and the pFe(3+) value of 22.3. Two equilibrating isomeric forms of the iron(III) complex exist under biological conditions. Deferitazole also binds the trivalent metals Al(III) and La(III) with high affinity; log??2 values, 26.68 and 21.55 respectively. The affinity of deferitazole for divalent cations is somewhat lower, with the exception of Cu(II) which possesses a log??2 value of 25.5; deferitazole scavenges iron from labile sources such as citrate and albumin with efficiencies comparable with those of other therapeutic iron chelators, including deferasirox, deferiprone and desferrioxamine. The Fe(III)(deferitazole)2 is stable under physiological conditions and does not redox cycle. The high affinity of deferitazole for iron(III) renders it unlikely that this chelator will lead to the redistribution of iron and consequently deferitazole shows considerable promise as a therapeutic iron(III) chelator. PMID:25687725

  5. Current approach to iron chelation in children.

    PubMed

    Aydinok, Yesim; Kattamis, Antonis; Viprakasit, Vip

    2014-06-01

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

  6. Development of an upconverting chelate assay

    NASA Astrophysics Data System (ADS)

    Xiao, Xudong; Haushalter, Jeanne P.; Kotz, Kenneth T.; Faris, Gregory W.

    2005-04-01

    We report progress on performing a cell-based assay for the detection of EGFR on cell surfaces by using upconverting chelates. An upconversion microscope has been developed for performing assays and testing optical response. A431 cells are labeled with europium DOTA and imaged using this upconverting microscope.

  7. Composite Ferrous Powder Metallurgy Structures: Mechanical Properties and Stress Analysis

    NASA Astrophysics Data System (ADS)

    Ahmed, M. N.; Vedula, M.; Koczak, M. J.

    1990-11-01

    Macrocomposite mechanics modeling is done for asymmetrical triplex structures. Relative parameters are obtained for the location of the centroid and the moment of inertia of triplex structures. The general analysis described can be applied to the special cases of symmetrical sandwich and asymmetrical duplex structures. The stress analysis includes the effect of the residual stress, and residual stress factors are determined for the special case of asymmetricaduplex structures. The rule-of-mixtures yield strength calculation with use of the relative parameters and residual stress factors was found to correlate very well with experimental results for macrocomposite ferrous powder metallurgy (P/M) duplex, 4620 and 4660, structures. The effects of volume fraction and the variations of elastic moduli of the constituents are examined.

  8. Equilibria between ferrous and ferric chlorides in molten chloride salts

    NASA Astrophysics Data System (ADS)

    Zhao, Guangwen; Tian, Qiuzhan; Duan, Shuzhen

    1990-02-01

    Equilibria between ferrous and ferric chlorides in molten salts have been studied for improving magnesium electrolysis and molten salt chlorination. The apparent equilibrium constants, K, of reaction FeCl2(melt)+0.5Cl2(gas)=FeCl3(melt) were obtained. Measured values of K were in good agreement with computed ones from regression equations. The composition of the melts, the partial pressure of chlorine, and the temperature were found to have important effects on K, and the effect of dissolved iron was smaller than that of other factors. At identical other conditions, the largest values of K were observed in system 3, which suggested that the current efficiency for electrolysis of MgCl2 should be lower when carnallite was used as electrolyte and that catalysis of iron species in molten salt chlorination would be better when molten salt systems containing high potassium chloride were used.

  9. [Research advances on anaerobic ferrous-oxidizing microorganisms].

    PubMed

    Zhang, Meng; Zheng, Ping; Ji, Jun-yuan

    2013-08-01

    Anaerobic ferrous-oxidizing microorganisms (AFOM) are one of the important discoveries in microbiology, geology and environmental science. The study of AFOM is of significance to make clear the banded iron formations (BIFs), promote the biogeochemical cycles of iron, nitrogen and carbon, enrich the microbiological content, develop new biotechnologies for anaerobic iron oxidation, and explore the ancient earth environment and extraterrestrial life. This paper summarized the research advances on AFOM, introduced the habitats of AFOM, discussed the biodiversity and the nutritive and metabolic characteristics of AFOM, and assessed the potential functions of AFOM. An outlook was made on the future researches of new species AFOM, their microbial metabolism mechanisms, and their development and applications. PMID:24380362

  10. Oxidation of ferrous ions by ozone in acidic solutions

    SciTech Connect

    Loegager, T.; Holcman, J.; Sehested, K.; Pedersen, T. )

    1992-08-19

    In the aqueous phase of the atmosphere (aerosols, clouds, fog, etc.), where iron, acids, and ozone are simultaneously present, the oxidation of Fe{sup 2+} by O{sub 3} is very important as an ozone sink. The oxidation of ferrous ions by ozone in acidic solution of pH 0-2 was studied using a stopped-flow spectrophotometer. The reaction can be characterized as an oxygen atom transfer from O{sub 3} to Fe{sup 2+}. An intermediate product assigned to be the ferryl ion, FeO{sup 2+}, was found and its UV-vis spectrum measured. A reaction mechanism is proposed, which accounts for all the authors experimental results.

  11. Bacterial oxidation of ferrous iron at low temperatures.

    PubMed

    Kupka, Daniel; Rzhepishevska, Olena I; Dopson, Mark; Lindstrm, E Brje; Karnachuk, Olia V; Tuovinen, Olli H

    2007-08-15

    This study comprises the first report of ferrous iron oxidation by psychrotolerant, acidophilic iron-oxidizing bacteria capable of growing at 5 degrees C. Samples of mine drainage-impacted surface soils and sediments from the Norilsk mining region (Taimyr, Siberia) and Kristineberg (Skellefte district, Sweden) were inoculated into acidic ferrous sulfate media and incubated at 5 degrees C. Iron oxidation was preceded by an approximately 3-month lag period that was reduced in subsequent cultures. Three enrichment cultures were chosen for further work and one culture designated as isolate SS3 was purified by colony isolation from a Norilsk enrichment culture for determining the kinetics of iron oxidation. The 16S rRNA based phylogeny of SS3 and two other psychrotolerant cultures, SS5 from Norilsk and SK5 from Northern Sweden, was determined. Comparative analysis of amplified 16S rRNA gene sequences showed that the psychrotolerant cultures aligned within Acidithiobacillus ferrooxidans. The rate constant of iron oxidation by growing cultures of SS3 was in the range of 0.0162-0.0104 h(-1) depending on the initial pH. The oxidation kinetics followed an exponential pattern, consistent with a first order rate expression. Parallel iron oxidation by a mesophilic reference culture of Acidithiobacillus ferrooxidans was extremely slow and linear. Precipitates harvested from the 5 degrees C culture were identified by X-ray diffraction as mixtures of schwertmannite (ideal formula Fe(8)O(8)(OH)(6)SO(4)) and jarosite (KFe(3)(SO(4))(2)(OH)(6)). Jarosite was much more dominant in precipitates produced at 30 degrees C. PMID:17304566

  12. Shortened forms of provocative lead chelation

    SciTech Connect

    Sokas, R.K.; Atleson, J.; Keogh, J.P.

    1988-05-01

    Shortened urinary lead collections following provocative chelation have been standardized for pediatric patients, but have not been considered adequate for adults. This study compared shortened urine collections for lead excretion post chelation with standard 24-hour collections. Thirty-five patients without known current lead exposure and with serum creatinine measurements less than 2 mg/dL were hospitalized and had provocative chelation performed as follows: One gram of CaNa2-ethylenediaminetetraacetic acid (EDTA) was administered in 250 mL of a 5% dextrose in water solution intravenously over one hour; the same dose was repeated 12 hours later. A 24-hour urine collection for lead excretion was begun at the time of initiation of the first dose. At three hours and six hours from start of first dose, each patient was instructed to void, total volume to that point was recorded, and a 10-mL aliquot was withdrawn for lead measurement. Both three-hour and six-hour urinary lead excretion following a single dose of EDTA correlated linearly with 24-hour lead excretion post chelation (r = .89 and .94, respectively). When a 24-hour level of 600 micrograms was defined as true positive the three-hour collection had a sensitivity of 76% and specificity of 95% and six-hour urinary lead excretion had 82% sensitivity and 100% specificity. Mild renal insufficiency (reflected by serum creatinine levels between 1.5 and 2.1 mg/dL) did not significantly alter the correlation between three-, six-, and 24-hour urinary post-chelation lead excretion.

  13. Chelation therapy after the Trial to Assess Chelation Therapy: results of a unique trial

    PubMed Central

    Avila, Maria D.; Escolar, Esteban; Lamas, Gervasio A.

    2014-01-01

    Purpose of review EDTA chelation therapy has been in off-label use for the treatment of atherosclerosis. We review the results of the first large-scale randomized trial of this treatment. Recent findings The trial to assess chelation therapy was a $30 million National Institutes of Health-funded study of the safety and efficacy of EDTA-based chelation infusions in 1708 post-myocardial infarction (MI) patients. The trial to assess chelation therapy demonstrated a significant (P?=?0.035) 18% reduction in a combined primary endpoint of death, MI, stroke, coronary revascularization, or hospitalization for angina. In diabetic patients the benefit was more extreme, with a 41% relative reduction in risk (P?=?0.0002) and a 43% reduction in total mortality (P?=?0.011). Safety data were favorable. A reduction of oxidative stress by chelation of toxic metals has been proposed as a possible mechanism of action. Summary Recent research suggests that EDTA chelation may be a well-tolerated and effective treatment for post-MI patients. Future replication and mechanistic studies are important prior to implementation in all post-MI patients. PMID:25023079

  14. A randomized, double-blind clinical study on the safety and tolerability of an iron multi-amino acid chelate preparation in premenopausal women.

    PubMed

    Fouad, Gameil T; Evans, Malkanthi; Sharma, Prachi; Baisley, Joshua; Crowley, David; Guthrie, Najla

    2013-03-01

    ABSTRACT Considerable risk of iron deficiency has been identified in premenopausal women because of the adverse effects associated with commercial iron preparations. This study examined the safety and tolerability of a novel iron multi-amino acid chelate (IMAAC) preparation in premenopausal women. A single-centre, randomized, double-blind, three-arm placebo-controlled (n = 60) study was conducted where subjects received one of three test materials: IMAAC (600 mg) or ferrous sulfate (600 mg) each containing 25 mg of elemental iron, or placebo as a single daily dose for 7 days. After testing, there were no significant differences found in any of the hematological outcomes between the different test groups. The safety analyses showed that a significantly (p = .044) higher number of patients reported adverse events when taking the ferrous sulfate supplement compared to IMAAC. A significantly lower number of adverse effects (p = .008) were reported by subjects on IMAAC. The current study demonstrated the superiority of the IMAAC preparation over ferrous sulfate with regards to tolerability and adverse effects. PMID:23387416

  15. Upconversion from aqueous phase lanthanide chelates

    PubMed Central

    Xiao, Xudong; Haushalter, Jeanne P.; Faris, Gregory W.

    2006-01-01

    We have prepared and characterized several lanthanide ion complexes of multidentate ligands or chelates in an effort to develop new upconverting luminescent labels that can be immune to autofluorescence and photobleaching. This study has involved the characterization of various chelates of Nd, Er, and Tm with respect to relative luminescent efficiency and excited-state lifetimes and explored various two-photon stepwise excitation mechanisms. Using peak laser powers near 100 kW, the upconversion emissions of Nd in Nd(EDTA)2 5− at 386 nm, Er in Er(DPA)3 3− at 550 nm, and Tm in Tm(DPA)3 3− at 480 nm, at levels of ~10−12 moles can be detected. PMID:16075534

  16. Ferrous iron oxidation by Thiobacillus ferrooxidans: inhibition with benzoic acid, sorbic acid and sodium lauryl sulfate

    SciTech Connect

    Onysko, S.J.

    1984-07-01

    Acid mine drainage is formed by the weathering or oxidation of pyritic material exposed during coal mining. The rate of pyritic material oxidation can be greatly accelerated by certain acidophilic bacteria such as Thiobacillus ferrooxidans which catalyse the oxidation of ferrous to ferric iron. A number of organic compounds, under laboratory conditions, can apparently inhibit both the oxidation of ferrous to ferric iron by T. ferrooxidans and the weathering of pyritic material by mixed cultures of acid mine drainage micro-organisms. Sodium lauryl sulphate (SLS), an anionic surfactant has proved effective in this respect. Benzoic acid, sorbic acid and SLS at low concentrations, each effectively inhibited bacterial oxidation of ferrous iron in batch cultures of T. ferrooxidans. The rate of chemical oxidation of ferrous iron in low pH, sterile, batch reactors was not substantially affected at the tested concentrations of any of the compounds.

  17. Ferrous iron oxidation by Thiobacillus ferrooxidans: inhibition with benzoic acid, sorbic acid, and sodium lauryl sulfate

    SciTech Connect

    Onysko, S.J.; Kleinmann, R.L.P.; Erickson, P.M.

    1984-07-01

    Thiobacillus ferrooxidans promote indirect oxidation of pyrite through the catalysis of the oxidation of ferrous iron to ferric iron, which is an effective oxidant of pyrite. These bacteria also may catalyze direct oxidation of pyrite by oxygen. A number of organic compounds, under laboratory conditions, can apparently inhibit both the oxidation of ferrous iron to ferric iron by T. ferrooxidans and the weathering of pyritic material by mixed cultures of acid mine drainage microorganisms. In this study, benzoic acid, sorbic acid, and sodium lauryl sulfate at low concentrations (5 to 10 mg/liter) each effectively inhibited bacterial oxidation of ferrous iron in batch cultures of Thiobacillus ferrooxidans. The rate of chemical oxidation of ferrous iron in low-pH, sterile batch reactors was not substantially affected at the tested concentrations (5 to 50 mg/liter) of any of the compounds.

  18. Iron lung: bronchoscopic and pathological consequences of aspiration of ferrous sulphate.

    PubMed Central

    Godden, D J; Kerr, K M; Watt, S J; Legge, J S

    1991-01-01

    Acute bronchial damage was caused by aspiration of a ferrous sulphate tablet, early histological changes (unlike in the few previously reported cases) being observed in the biopsy specimens. Images PMID:2014497

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

    NASA Technical Reports Server (NTRS)

    Miyoshi, K.; Buckley, D. H.

    1983-01-01

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

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

    NASA Technical Reports Server (NTRS)

    Miyoshi, K.; Buckley, D. H.

    1984-01-01

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

  1. Development of cast ferrous alloys for Stirling engine application

    NASA Technical Reports Server (NTRS)

    Lemkey, F. D.

    1982-01-01

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

  2. NO2(-)-mediated nitrosylation of ferrous microperoxidase-11.

    PubMed

    Ascenzi, Paolo; Sbardella, Diego; Fiocchetti, Marco; Santucci, Roberto; Coletta, Massimo

    2015-12-01

    Microperoxidase-11 (MP11) is an undecapeptide derived from horse heart cytochrome c (cyt c) and characterized by a covalently-linked solvent-exposed heme group. Here, kinetics of the NO2(-)-mediated nitrosylation of ferrous MP11 (MP11-Fe(II)) is reported. Data were obtained between pH6.4 and 8.2, at 20.0C. The NO2(-)-mediated conversion of MP11-Fe(II) to MP11-Fe(II)-NO requires one proton; accordingly, values of the apparent second-order rate constant (kon) decrease by about two orders of magnitude from (2.90.3)10(1)M(-1)s(-1) to (5.00.6)10(-1)M(-1)s(-1) upon increasing pH from 6.4 to pH8.2. The slope of the linear fitting of Logkon versus pH is -1.000.06. Values of kon for the NO2(-)-mediated nitrosylation of MP11-Fe(II) are similar to those of penta-coordinated cardiolipin-bound horse heart cyt c, exceeding by about two orders of magnitude those of wild-type horse heart cyt c. Present results highlight the role of heme distal residues in modulating horse heart cyt c reactivity. PMID:26277417

  3. Characterization of particulate emissions from non-ferrous smelters

    SciTech Connect

    Bennett, R.L.; Knapp, K.T.

    1989-01-01

    Chemical-composition and particle-size data for particulate emissions from stationary sources are required for environmental health-effect assessments, air chemistry studies, and air-quality-modelling investigations such as source apportionment. In this study, particulate emissions from a group of non-ferrous smelters were physically and chemically characterized. Emission samples were collected at the baghouse outlets from smelter furnaces and at smelter acid plant stacks at three locations: a zinc, a lead, and a copper smelter. Mass emission rate determinations were made by EPA reference methods. Cascade impactors were used to collect in-stack samples for particle-size distribution measurements. Particulate samples for chemical characterization were collected on membrane filters for analysis by X-ray fluorescence spectroscopy. Development measurement techniques required to determine the elemental composition of the total mass and sized fractions of the emission are discussed. Results of the tests at the three smelters include total mass and elemental emission rates, particle-size distribution, and the elemental composition of the total particulate mass and of sized fractions from both the smelter furnaces and acid plants.

  4. [Ferrous sulfate: acute poisoning with a frequent use drug].

    PubMed

    Mariano, Daz; Cabrerizo, Silvia; Docampo, Patricia C

    2011-02-01

    The iron is the main component of hemoglobin and is also part of myoglobin and enzymes. Its deficit is the most common cause of nutritional anemia in humans. The use of iron salts is very common in children, because they are indicated for prophylaxis and treatment of iron deficiency anemia. The availability in households and the emergence of flavored formulations that promote adherence to treatment, greatly assist in this type of poisoning. Usually, the overdose is considered a low hazard, because it is a mineral supplement added in many of the baby food. Iron in free state is able of producing toxicity, disrupting multiple cellular processes by catalyzing redox reactions with lipid peroxidation and free radical formation. We report a case of serious toxicity by iron salts, in which early intervention and management with specific chelator, allowed a favorable evolution. PMID:21283930

  5. Removal of cyanide compounds from coking wastewater by ferrous sulfate: Improvement of biodegradability.

    PubMed

    Yu, Xubiao; Xu, Ronghua; Wei, Chaohai; Wu, Haizhen

    2016-01-25

    The effect of ferrous sulfate (FeSO4) treatment on the removal of cyanide compounds and the improvement of biodegradability of coking wastewater were investigated by varying Fe:TCN molar ratios. Results suggested that the reaction between FeSO4 and coking wastewater was a two-step process. At the first step, i.e., 0?Fe:TCN?1.0, the reaction mechanisms were dominated by the precipitation of FeS, the complexation of CN(-), and the coagulation of organic compounds. The COD of coking wastewater decreased from 3748.1mg/L to 3450.2mg/L, but BOD5:COD (B/C) was improved from 0.30 to 0.51. At the second step, i.e., 1.0ferrous ions was the dominating mechanism. The COD showed a continuous increase to 3542.2mg/L (Fe:TCN=3.2) due to the accumulated ferrous ions in coking wastewater. Moreover, B/C decreased progressively to 0.35, which was attributed to the negative effects of excess ferrous ions on biodegradability. To improve coking wastewater's biodegradability, a minimum ferrous dosage is required to complete the first step reaction. However, the optimum ferrous dosage should be determined to control a safe residual TCN in coking wastewater for the further biological treatment. PMID:26547041

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

    PubMed

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

    2015-01-01

    The recovery of ferrous and non-ferrous metals from waste to energy (WTE) ash continues to advance as the sale of removed metals improves the economics of waste combustion. Published literature suggests that Fe and Fe oxides play a role in suppressing Pb leaching in the Toxicity Characteristic Leaching Procedure (TCLP); further removal of ferrous metals from WTE ashes may facilitate higher Pb leaching under the TCLP. Eight WTE bottom ash size-fractions, from three facilities, were evaluated to assess the effect of metallic Fe addition and ferrous metal removal on TCLP leaching. Metallic Fe addition was demonstrated to reduce Pb leaching; the removal of ferrous metals by magnet resulted in a decrease in total available Pb (mg/kg) in most ash samples, yet Pb leachability increased in 5 of 6 ash samples. The research points to two chemical mechanisms to explain these results: redox interactions between Pb and Fe and the sorption of soluble Pb onto Fe oxide surfaces, as well as the effect of the leachate pH before and after metals recovery. The findings presented here indicate that generators, processors, and regulators of ash should be aware of the impact ferrous metal removal may have on Pb leaching, as a substantial increase in leaching may have significant implications regarding the management of WTE ashes. PMID:25464288

  7. Effect of abomasal ferrous lactate infusion on phosphorus absorption in lactating dairy cows.

    PubMed

    Feng, X; Knowlton, K F; Dietrich, A D; Duncan, S

    2013-07-01

    The objective of this study was to evaluate the effect of ferrous lactate infusion on postruminal P absorption in lactating dairy cows. Four ruminally cannulated lactating cows were used in a 44 Latin square design with 14 d per period. Cows were fed a basal diet containing 0.39% P, providing 100% of the calculated P requirement. On d 8 to 14 of each period, each cow was infused with 0, 200, 500, or 1,250mg of Fe/d in the form of ferrous lactate solution (ferrous lactate in 1L of double-distilled water) into the abomasum. Infusate was formulated to approximate 0, 2, 5, or 12.5mg of Fe/L in drinking water with 100L of water intake/d. Total fecal collection was conducted in the last 4 d of each period to measure nutrient digestion and excretion. Dry matter intake, milk yield, and milk composition were not affected by treatment. Digestibility of DM, NDF, and nitrogen decreased linearly with increasing ferrous lactate infusion. Infusion of ferrous lactate did not affect intake and digestibility of total P, inorganic P, or phytate P. In lactating cows, P absorption was not negatively influenced by abomasally infused ferrous lactate up to 1,250mg of Fe/d. PMID:23660146

  8. Comparative studies on storage stability of ferrous iron in whole wheat flour and flat bread (naan).

    PubMed

    Alam, Sahib; Shah, Hamid Ullah; Saleemullah; Riaz, Ayesha

    2007-02-01

    Whole wheat flour was fortified with premix containing ferrous sulfate, ethylenediamine tetraacetic acid and folic acid (20.0:20.0:1.5 ppm) and was stored at ambient temperature for 60 days. Naans (flat bread) were prepared from 0 ppm, 25 ppm, 50 ppm and 75 ppm ferrous iron-fortified flour samples at 10-day intervals and were analyzed for physicochemical constants and sensory evaluation. It was observed that flour containing 75 ppm ferrous sulfate contained the highest iron residues. The total iron in flour samples showed no significant difference, while ferrous iron significantly decreased in fortified flour (0.53-3.08%) and in the naans (0.42-3.48%) because of its oxidation to ferric iron during storage. The phytic acid content decreased (0.886-0.810%) significantly during the same storage period. Iron levels affected some sensory characteristics significantly (P < or =0.05), including color, texture, flexibility, chewability and overall acceptability of the naans, but not taste and flavor. The sensory attributes of naans illustrated that naans containing 50 ppm ferrous iron are more acceptable than those prepared with 75 ppm ferrous iron. PMID:17415956

  9. Anaerobic oxidation of ferrous iron by purple bacteria, a new type of phototrophic metabolism.

    PubMed Central

    Ehrenreich, A; Widdel, F

    1994-01-01

    Anoxic iron-rich sediment samples that had been stored in the light showed development of brown, rusty patches. Subcultures in defined mineral media with ferrous iron (10 mmol/liter, mostly precipitated as FeCO3) yielded enrichments of anoxygenic phototrophic bacteria which used ferrous iron as the sole electron donor for photosynthesis. Two different types of purple bacteria, represented by strains L7 and SW2, were isolated which oxidized colorless ferrous iron under anoxic conditions in the light to brown ferric iron. Strain L7 had rod-shaped, nonmotile cells (1.3 by 2 to 3 microns) which frequently formed gas vesicles. In addition to ferrous iron, strain L7 used H2 + CO2, acetate, pyruvate, and glucose as substrate for phototrophic growth. Strain SW2 had small rod-shaped, nonmotile cells (0.5 by 1 to 1.5 microns). Besides ferrous iron, strain SW2 utilized H2 + CO2, monocarboxylic acids, glucose, and fructose. Neither strain utilized free sulfide; however, both strains grew on black ferrous sulfide (FeS) which was converted to ferric iron and sulfate. Strains L7 and SW2 grown photoheterotrophically without ferrous iron were purple to brownish red and yellowish brown, respectively; absorption spectra revealed peaks characteristic of bacteriochlorophyll a. The closest phototrophic relatives of strains L7 and SW2 so far examined on the basis of 16S rRNA sequences were species of the genera Chromatium (gamma subclass of proteobacteria) and Rhodobacter (alpha subclass), respectively. In mineral medium, the new isolates formed 7.6 g of cell dry mass per mol of Fe(II) oxidized, which is in good agreement with a photoautotrophic utilization of ferrous iron as electron donor for CO2 fixation. Dependence of ferrous iron oxidation on light and CO2 was also demonstrated in dense cell suspensions. In media containing both ferrous iron and an organic substrate (e.g., acetate, glucose), strain L7 utilized ferrous iron and the organic compound simultaneously; in contrast, strain SW2 started to oxidize ferrous iron only after consumption of the organic electron donor. Ferrous iron oxidation by anoxygenic phototrophs is understandable in terms of energetics. In contrast to the Fe3+/Fe2+ pair (E0 = +0.77 V) existing in acidic solutions, the relevant redox pair at pH 7 in bicarbonate-containing environments, Fe(OH)3 + HCO3-/FeCO3, has an E0' of +0.2 V. Ferrous iron at pH 7 can therefore donate electrons to the photosystem of anoxygenic phototrophs, which in purple bacteria has a midpoint potential around +0.45 V. The existence of ferrous iron-oxidizing anoxygenic phototrophs may offer an explanation for the deposition of early banded-iron formations in an assumed anoxic biosphere in Archean times. Images PMID:7811087

  10. Chelators whose affinity for calcium is decreased by illumination

    NASA Technical Reports Server (NTRS)

    Tsien, Roger Y. (Inventor); Grynkiewicz, Grzegorz (Inventor); Minta, Akwasi (Inventor)

    1987-01-01

    The present invention discloses a group of calcium chelating compounds which have a descreased affinity for calcium following illumination. These new compounds contain a photolabile nitrobenzyl derivative coupled to a tetracarboxylate Ca.sup.2+ chelating parent compound having the octacoordinate chelating groups characteristic of EGTA or BAPTA. In a first form, the new compounds are comprised of a BAPTA-like chelator coupled to a single 2-nitrobenzyl derivative, which in turn is a photochemical precursor of a 2-nitrosobenzophenone. In a second form, the new compounds are comprised of a BAPTA-like chelator coupled to two 2-nitrobenzyl derivatives, themselves photochemical prcursors of the related 2-nitrosobenzophenones. The present invention also discloses a novel method for preparing 1-hydroxy- or 1-alkoxy-1-(2-nitroaryl)-1-aryl methanes. Methanes of this type are critical to the preparation of, or actually constitute, the photolabile Ca.sup.2+ chelating compounds disclosed and claimed herein.

  11. Ferrous Iron Diffusion in Periclase across the Spin Transition

    NASA Astrophysics Data System (ADS)

    Ammann, M. W.; Brodholt, J. P.; Dobson, D. P.

    2010-12-01

    Theoretical investigations on the spin-transition in ferro-periclase revealed that the transition is not sharp but occurs throughout the lower mantle and is not completed at the core-mantle boundary. This continuous transition results in a smooth variation of the elastic properties of the material making the change of the spin state difficult to detect using seismic waves. Thus, its geophysical significance remains unclear. The effect of the spin-transition on rheology is currently unknown. While diffusion-experiments are limited to conditions of the shallow lower mantle, ab initio methods allow us to calculate absolute diffusion rates at any pressure and temperature [1,2]. We here present results of density-functional-theory calculations on absolute diffusion rates of high- and low-spin ferrous iron in periclase. The diffusivity of high- and low-spin iron depends on the physical conditions (pressure and temperature), iron concentration and the value of the chosen Hubbard U. We also find that low-spin iron swaps back to high-spin during migration, such that the difference between high- and low-spin migration enthalpies only depends on the energy-difference of the ground-states. We compared our absolute diffusion rates with experimental data of magnesium-iron interdiffusion in ferro-periclase at temperatures between 1873 K and 2273 K and at pressures ranging from 7 GPa to 35 GPa. All our diffusion rates are in excellent agreement with all the available experimental data. Our results show that throughout the Earth's lower mantle, iron diffuses at a similar rate as magnesium. Thus, the effect of the spin transition of ferrous iron has no significant impact on the rheology of ferro-periclase in the Earth's mantle, and ferro-periclase is much weaker than perovskite throughout the mantle. We conclude, therefore, that ferro-periclase can only control the viscosity of the mantle in regions where it becomes interconnected, such as areas of high strain around slabs or near plumes. At much higher pressures, such as in Super-Earths, low-spin iron diffusion is expected to become much slower than magnesium, making ferro-periclase more viscous than pure periclase. Whether ferro-periclase becomes more viscous than post-perovskite will depend on the vacancy concentration of the phases. REFERENCES: [1] Ammann, M. W., Brodholt, J. P., Dobson, D. P., 2010. Simulating Diffusion. Reviews in Mineralogy and Geochemistry: Theoretical and Computational Methods in Mineral Physics: Applications to Geophysics 71, 201-224. [2] Ammann, M. W., Brodholt, J. P., Wookey, J., Dobson, D. P., 2010. First-principles constraints on diffusion in lower-mantle minerals and a weak D" layer. Nature 466, 462-465.

  12. Degradation of ciprofloxacin and sulfamethoxazole by ferrous-activated persulfate: implications for remediation of groundwater contaminated by antibiotics.

    PubMed

    Ji, Yuefei; Ferronato, Corinne; Salvador, Arnaud; Yang, Xi; Chovelon, Jean-Marc

    2014-02-15

    The wide occurrence of antibiotics in groundwater raised great scientific interest as well as public awareness in recent years due to their potential ability to spread antibiotic resistant gene and pose risk to humans. The present study investigated the ferrous ion (Fe(II)) activated decomposition of persulfate (S2O8(2-)), as a potential in situ chemical oxidation (ISCO) approach, for remediation of groundwater contaminated by antibiotics. Fe(II)-persulfate mediated ciprofloxacin (CIP) degradation was found to be more efficient than sulfamethoxazole (SMX) at near neutral pH (pH6.0), probably due to the higher electric density in CIP molecule and its ability to form complex with Fe(II) as a ligand. Hydroxyl (HO) and sulfate radical (SO4(-)) were determined to be responsible for the degradation of CIP and SMX in Fe(II)-persulfate system by molecular probes. No enhancement in the degradation of CIP was observed when citrate (CA), ethylenediaminetetraacetate (EDTA) and (S,S)-ethylenediamine-N,N'-disuccinate (EDDS) were used as Fe(II) chelating agents in Fe(II)-persulfate system. For SMX, CA and EDTA accelerated the degradation by Fe(II)-persulfate. Degradation of antibiotics in river water matrix was nearly the same as that in Milli-Q water, implying the possibility of using Fe(II)-persulfate for antibiotics depletion under environmentally relevant condition. A comparison of the degradation efficiency of SMX with other sulfonamides and sulfanilic acid indicated that the heterocyclic ring has a large impact on the degradation of sulfonamides. Transformation products of CIP and SMX by Fe(II)-persulfate were analyzed by solid phase extraction-liquid chromatography-mass spectrometry (SPE-LC-MS) technique. Based on the intermediate products, Fe(II)-persulfate mediated CIP degradation pathways were tentatively proposed. PMID:24342085

  13. Recent advances in cancer treatment by iron chelators.

    PubMed

    Corc, Vincent; Gouin, Sbastien G; Renaud, Stphanie; Gaboriau, Franois; Deniaud, David

    2016-01-15

    The development of new therapeutic alternatives for cancers is a major public health priority. Among the more promising approaches, the iron depletion strategy based on metal chelation in the tumoral environment has been particularly studied in recent decades. After a short description of the importance of iron for cancer cell proliferation, we will review the different iron chelators developed as potential chemotherapeutics. Finally, the recent efforts to vectorize the chelating agents specifically in the microtumoral environment will be discussed in detail. PMID:26684852

  14. Intermediate-spin ferrous iron in the Earth's lower mantle?

    NASA Astrophysics Data System (ADS)

    Hsu, Han; Wentzcovitch, Renata

    2014-03-01

    Using density functional theory + self-consistent Hubbard U (DFT +Usc) calculations, we investigate intermediate-spin (IS) ferrous iron (Fe2+) in major lower-mantle minerals, ferropericlase (Fp) and magnesium silicate (MgSiO3) perovskite (Pv). In both minerals, two distinct types of IS Fe2+ are found. In Fp, while both types of IS Fe2+ are configured t2g5 eg1,one has a dz2 electron\\ and the other has a dx 2 - y 2 electron, referred to as the IS(z2) and IS(x2 - y2) state, respectively.\\ The IS(z2) state has an exceptionally high QS (>= 5.5 mm/s); the IS(x2 - y2) state has a quite low QS (<0.5 mm/s). Also, the IS(z2) state has a stronger on-site Coulomb interaction and much higher energy. In Pv, while Fe2+ substitutes Mg in the dodecahedral site, it is effectively under a distorted octahedral crystal field, and the two IS states can be characterized by their filled eg-like orbitals as well. These two IS Fe2+, in contrast to those in Fp, are energetically competitive, and they both have a small QS (<1.6 mm/s). Our calculations show that all IS Fe2+ in lower-mantle minerals are unfavorable, and their QSs are all inconsistent with experiments. Therefore, IS Fe2+ is highly unlikely in the Earth's lower mantle. Research supported by Taiwan NSC under Grant No. NSC 102-2112-M-008-001-MY3 (H.H.) and NSF Awards EAR-1319361, -1019853, and -0810272 (R.M.W).

  15. Transformation of graphene oxide by ferrous iron: Environmental implications.

    PubMed

    Wang, Fanfan; Wang, Fang; Gao, Guandao; Chen, Wei

    2015-09-01

    Abiotic transformation of graphene oxide (GO) in aquatic environments can markedly affect the fate, transport, and effects of GO. The authors observed that ferrous iron (Fe[II])-an environmentally abundant, mild reductant-can significantly affect the physicochemical properties of GO (examined by treating aqueous GO suspensions with Fe(2+) at room temperature, with doses of 0.032?mM Fe(2+) ?per?mg/L, 0.08?mM Fe(2+) ?per?mg/L, and 0.32?mM Fe(2+) ?per?mg/L GO). Microscopy data showed stacking of GO nanosheets on Fe(2+) treatment. Spectroscopy evidence (X-ray diffraction, Fourier transform infrared transmission, Raman and X-ray photoelectron spectroscopy) showed significant changes in GO surface O-functionalities, in terms of loss of epoxy and carbonyl groups but increase of carboxyl group. The reduction mechanisms were verified by treating model organic molecules (styrene oxide, p-benzoquinone, and benzoic acid) resembling O-containing fragments of GO macromolecules with Fe(2+). With sedimentation and adsorption experiments (using bisphenol A as a model contaminant), the authors demonstrated that Fe(2+) reduced GOs still maintained relatively high colloidal stability, whereas their adsorption affinities were significantly enhanced. Thus, reduction of GO by mild reductants might be of greater environmental concerns than by stronger reducing agents (e.g., N2H4 and S(2-)), because the latter can result in too significant losses of surface O-functionalities and colloidal stability of GO. This interesting aspect should be given consideration in the risk assessment of GO. PMID:25939959

  16. Ultrafine Particulate Ferrous Iron and Anthracene Associations with Mitochondrial Dysfunction

    SciTech Connect

    Faiola, Celia; Johansen, Anne M.; Rybka, Sara; Nieber, Annika; Thomas-Bradley, Carin; Bryner, Stephanie; Johnston, Justin M.; Engelhard, Mark H.; Nachimuthu, Ponnusamy; Owens, Kalyn S.

    2011-04-20

    The ultrafine size fraction of ambient particles (ultrafine particles, UFP, diameter < 100 nm) has been identified as being far more potent in their adverse health effects than their larger counterparts, yet, the detailed mechanisms for why UFP display such distinctive toxicity are not well understood. In the present study, ambient UFP were exposed to mitochondria while monitoring electron transport chain (ETC) activity as a model system for biochemical toxicity. UFP samples were collected in rural (Ellensburg, WA) and urban environments (Seattle, WA) and chemically characterized for total trace metals, ferrous (Fe(II)) and easily reducible ferric (Fe(III)) iron, polycyclic aromatic hydrocarbons, and surface constituents with X-ray photoelectron spectroscopy (XPS). Low doses of UFP (8 g mL-1) caused a decrease in mitochondrial ETC function compared to controls in 94% of the samples after The 20 min of exposure. Significant correlations exist between initial %ETC inhibition (0-10 min) and Fe(II) (R=0.55, P=0.03, N=15), anthracene (R=0.74, P<0.01, N=13), and %C-O surface bonds (R=0.56, P=0.03, N=15), whereby anthracene and %C-O correlate as well (R=0.58, P=0.03, N=14). No significant associations were identified with total Fe and other trace metals. Results from this study indicate that the redox active fraction of Fe as well as the abundance of anthracene-related, C-O containing, surface structures may contribute to the initial detrimental behavior of UFP, thus supporting the idea that the Fe(II)/Fe(III) and certain efficient hydroquinone/quinone redox pairs may play an important role likely due to their potential to produce reactive oxygen species (ROS).

  17. Iron chelation and tumor cell calcium homeostasis.

    PubMed

    Anghileri, L J

    1994-01-01

    The effects of iron chelation on calcium homeostasis of Ehrlich carcinoma cells were studied using 59Fe-ferric lactate and 45CaCl2. Desferrioxamine action on bound iron is characterized by the presence of an insoluble fraction located deep in the cell membrane and another soluble fraction on the cell surface. The competitive binding by albumin suggests that the iron is bound by protein containing molecular structures of the cell. The modification of cellular calcium homeostasis induced by ferric lactate, which is a phenomenon inherent in cell injury, is not caused by lipid peroxidation. The role of iron-induced cellular calcium homeostasis in carcinogenesis is discussed. PMID:8074502

  18. Metal regeneration of iron chelates in nitric oxide scrubbing

    DOEpatents

    Chang, S.G.; Littlejohn, D.; Shi, Y.

    1997-08-19

    The present invention relates to a process of using metal particles to reduce NO to NH{sub 3}. More specifically, the invention concerns an improved process to regenerate iron (II) (CHELATE) by reduction of iron (II) (CHELATE) (NO) complex, which process comprises: (a) contacting an aqueous solution containing iron (II) (CHELATE) (NO) with metal particles at between about 20 and 90 C to reduce NO present, produce ammonia or an ammonium ion, and produce free iron (II) (CHELATE) at a pH of between about 3 and 8. The process is useful to remove NO from flue gas and reduce pollution. 34 figs.

  19. Metal regeneration of iron chelates in nitric oxide scrubbing

    DOEpatents

    Chang, Shih-Ger (El Cerrito, CA); Littlejohn, David (Oakland, CA); Shi, Yao (Berkeley, CA)

    1997-08-19

    The present invention relates to a process of using metal particles to reduce NO to NH.sub.3. More specifically, the invention concerns an improved process to regenerate iron (II) (CHELATE) by reduction of iron (II) (CHELATE) (NO) complex, which process comprises: a) contacting an aqueous solution containing iron (II) (CHELATE) (NO) with metal particles at between about 20.degree. and 90.degree. C. to reduce NO present, produce ammonia or an ammonium ion, and produce free iron (II) (CHELATE) at a pH of between about 3 and 8. The process is useful to remove NO from flue gas and reduce pollution.

  20. Chemical treatment of chelated metal finishing wastes.

    PubMed

    McFarland, Michael J; Glarborg, Christen; Ross, Mark A

    2012-12-01

    This study evaluated two chemical approaches for treatment of commingled cadmium-cyanide (Cd-CN) and zinc-nickel (Zn-Ni) wastewaters. The first approach, which involved application of sodium hypochlorite (NaOCl), focused on elimination of chelating substances. The second approach evaluated the use of sodium dimethyldithiocarbamate (DMDTC) to specifically target and precipitate regulated heavy metals. Results demonstrated that by maintaining a pH of 10.0 and an oxidation-reduction potential (ORP) value of +600 mV, NaOCl treatment was effective in eliminating all chelating substances. Cadmium, chromium, nickel, and zinc solution concentrations were reduced from 0.27, 4.44, 0.06, and 0.10 ppm to 0.16, 0.17, 0.03, and 0.06 ppm, respectively. Similarly, a 1% DMDTC solution reduced these same metal concentrations in commingled wastewater to 0.009, 1.142, 0.036, and 0.320 ppm. Increasing the DMDTC concentration to 2% improved the removal of all regulated heavy metals except zinc, the removal of which at high pH values is limited by its amphotericity. PMID:23342939

  1. Chelates of molybdenyl with o-hydroxyazomethines

    SciTech Connect

    Abramenko, V.L.; Garnovskii, A.D.; Surpina, L.V.; Kuzharov, A.S.

    1986-05-01

    Chelates of dioxomolybdenum(VI) with Schiff bases derived from salicylaldehyde and aliphatic, aromatic, and heterocyclic amines and diamines have been synthesized by ligand exchange and template synthesis methods. Complexes with the general formula MoO/sub 2/L/sub 2/ form of N-alkyl- and N-arylsalicylidenimines (HL). Chelates with molybdenum-ligand ratios equal to 1:1 and 1:2 are realized with heterocyclic azomethines. Bis(salicylidene) diimines form only complexes with a 1:1 composition. The compounds isolated are finely crystalline substances, which predominantly have a yellow color and limited solubility in methanol and dimethyl sulfoxide. On the basis of data from conductometry, UV, IR, and /sup 1/H NMR spectroscopy it has been postulated that the complexes have an octahedral structure with maintenance of the cis configuration of the MoO/sub 2/ group. A dimeric or polymeric structure has been proposed for the 1:1 complexes. The thermal decomposition of the azomethine complexes of molybdenum(VI) under dynamic conditions takes place in two stages and ultimately results in the formation of MoO/sub 3/.

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

    PubMed

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

    2015-05-01

    Basaltic glass (BG) is an amorphous ferrous iron [Fe(II)]-containing material present in basaltic rocks, which are abundant on rocky planets such as Earth and Mars. Previous research has suggested that Fe(II) in BG can serve as an energy source for chemolithotrophic microbial metabolism, which has important ramifications for potential past and present microbial life on Mars. However, to date there has been no direct demonstration of microbially catalyzed oxidation of Fe(II) in BG. In this study, three different culture systems were used to investigate the potential for microbial oxidation of Fe(II) in BG, including (1) the chemolithoautotrophic Fe(II)-oxidizing, nitrate-reducing "Straub culture"; (2) the mixotrophic Fe(II)-oxidizing, nitrate-reducing organism Desulfitobacterium frappieri strain G2; and (3) indigenous microorganisms from a streambed Fe seep in Wisconsin. The BG employed consisted of clay and silt-sized particles of freshly quenched lava from the TEB flow in Kilauea, Hawaii. Soluble Fe(II) or chemically reduced NAu-2 smectite (RS) were employed as positive controls to verify Fe(II) oxidation activity in the culture systems. All three systems demonstrated oxidation of soluble Fe(II) and/or structural Fe(II) in RS, whereas no oxidation of Fe(II) in BG material was observed. The inability of the Straub culture to oxidize Fe(II) in BG was particularly surprising, as this culture can oxidize other insoluble Fe(II)-bearing minerals such as biotite, magnetite, and siderite. Although the reason for the resistance of the BG toward enzymatic oxidation remains unknown, it seems possible that the absence of distinct crystal faces or edge sites in the amorphous glass renders the material resistant to such attack. These findings have implications with regard to the idea that Fe(II)-Si-rich phases in basalt rocks could provide a basis for chemolithotrophic microbial life on Mars, specifically in neutral-pH environments where acid-promoted mineral dissolution and utilization of dissolved Fe(II) as an energy source is not likely to take place. PMID:25915449

  3. Evaluation of the treatment of chromite ore processing residue by ferrous sulfate and asphalt.

    PubMed

    Moon, Deok Hyun; Wazne, Mahmoud; Koutsospyros, Agamemnon; Christodoulatos, Christos; Gevgilili, Halil; Malik, Moinuddin; Kalyon, Dilhan M

    2009-07-15

    The effectiveness of the treatment of chromite ore processing residue (COPR) with ferrous sulfate and encapsulation into asphalt were explored separately and in combination. The asphalt treatment was conducted by mixing COPR or ferrous sulfate pretreated COPR with varying amounts of asphalt. To assess the efficacy of the treatment, the leachability of toxicity characteristic leaching procedure (TCLP) total chromium (Cr) from all treated samples was determined for curing periods up to 16 months. X-ray absorption near edge structure (XANES) analyses were also performed to evaluate the Cr(6+) concentration in the selected samples. The combination treatment of ferrous sulfate and the encapsulation of the treated COPR into asphalt reduced the TCLP total Cr concentration to lower than the regulatory limit of 5mg/L for Cr contaminated soils, after 16 months. However, the Cr concentrations were still higher than the universal treatment standards (UTS) of 0.6 mg/L for hazardous waste. On the other hand, treatment with ferrous sulfate alone or the encapsulation of the COPR in asphalt failed to meet the TCLP total Cr concentration of 5mg/L, after 16 months. XANES analyses results showed that more than 75% Cr(6+) reduction was achieved upon pretreatment with ferrous sulfate. PMID:18992990

  4. Radiation Chemical and MR Studies of Aqueous Agarose Gels Containing Ferrous Ions.

    NASA Astrophysics Data System (ADS)

    Leghrouz, Amin Ahmad

    Aqueous agarose gels containing ferrous ions, in 0.05 N sulfuric acid have been studied after irradiation with 6-18 MeV electrons or ^{137} Cs gamma-rays. Such gels can sustain a radiolytic chain reaction, producing Fe ^{3+} with G(Fe^ {3+})-values up to 100 having been observed. The Fe^{3+} production is independent of dose rate between 0.434 and 3.74 Gy min ^{-1}. Dissolved oxygen is needed to maintain the chain reaction, and initial ferric yields are increased if the gel is oxygen saturated or if the ferrous concentration is decreased below 1 mM. The oxidation of ferrous to ferric alters the magnetic moment of the ion and its electron spin relaxation time, which in turn affects its ability to promote proton spin relaxation rates. Longitudinal proton magnetic relaxation rates are increased in proportion to ferric production, permitting visualization of dose levels in these gels by magnetic resonance imaging (MRI) techniques. Non-uniform dose distribution images of electron irradiated ferrous/agarose (FA) systems have been obtained using MRI. Images of radiation doses surrounding capillary tubes filled with radioactive material embedded in FA systems have also been obtained. In this work, another new method of using the ferrous/agarose gel system doped with xylenol orange to visualize the radiation dose distribution directly by eye has been developed. The color change developed depends both quantitatively and qualitatively on the concentrations of solutes in the gel.

  5. Melting of low-level radioactive non-ferrous metal for release

    SciTech Connect

    Quade, Ulrich; Kluth, Thomas; Kreh, Rainer

    2007-07-01

    Siempelkamp Nukleartechnik GmbH has gained lots of experience from melting ferrous metals for recycling in the nuclear cycle as well as for release to general reuse. Due to the fact that the world market prices for non-ferrous metals like copper, aluminium or lead raised up in the past and will remain on a high level, recycling of low-level contaminated or activated metallic residues from nuclear decommissioning becomes more important. Based on the established technology for melting of ferrous metals in a medium frequency induction furnace, different melt treatment procedures for each kind of non-ferrous metals were developed and successfully commercially converted. Beside different procedures also different melting techniques such as crucibles, gas burners, ladles etc. are used. Approximately 340 Mg of aluminium, a large part of it with a uranium contamination, have been molten successfully and have met the release criteria of the German Radiation Protection Ordinance. The experience in copper and brass melting is based on a total mass of 200 Mg. Lead melting in a special ladle by using a gas heater results in a total of 420 Mg which could be released. The main goal of melting of non-ferrous metals is release for industrial reuse after treatment. Especially for lead, a cooperation with a German lead manufacturer also for recycling of non releasable lead is being planned. (authors)

  6. Evaluation of Ferric and Ferrous Iron Therapies in Women with Iron Deficiency Anaemia

    PubMed Central

    Berber, Ilhami; Erkurt, Mehmet Ali; Aydogdu, Ismet; Kuku, Irfan

    2014-01-01

    Introduction. Different ferric and ferrous iron preparations can be used as oral iron supplements. Our aim was to compare the effects of oral ferric and ferrous iron therapies in women with iron deficiency anaemia. Methods. The present study included 104 women diagnosed with iron deficiency anaemia after evaluation. In the evaluations performed to detect the aetiology underlying the iron deficiency anaemia, it was found and treated. After the detection of the iron deficiency anaemia aetiology and treatment of the underlying aetiology, the ferric group consisted of 30 patients treated with oral ferric protein succinylate tablets (2 40?mg elemental iron/day), and the second group consisted of 34 patients treated with oral ferrous glycine sulphate tablets (2 40?mg elemental iron/day) for three months. In all patients, the following laboratory evaluations were performed before beginning treatment and after treatment. Results. The mean haemoglobin and haematocrit increases were 0.95?g/dL and 2.62% in the ferric group, while they were 2.25?g/dL and 5.91% in the ferrous group, respectively. A significant difference was found between the groups regarding the increase in haemoglobin and haematocrit values (P < 0.05). Conclusion. Data are submitted on the good tolerability, higher efficacy, and lower cost of the ferrous preparation used in our study. PMID:25006339

  7. Chelation Treatment for Autism Spectrum Disorders: A Systematic Review

    ERIC Educational Resources Information Center

    Davis, Tonya N.; O'Reilly, Mark; Kang, Soyeon; Lang, Russell; Rispoli, Mandy; Sigafoos, Jeff; Lancioni, Giulio; Copeland, Daelynn; Attai, Shanna; Mulloy, Austin

    2013-01-01

    Chelation treatment is used to eliminate specific metals from the body, such as mercury. It has been hypothesized that mercury poisoning may be a factor in autism and data suggest that perhaps 7% of individuals with autism spectrum disorder (ASD) have received chelation treatment. It would therefore seem timely to review studies investigating the…

  8. Reusable chelating resins concentrate metal ions from highly dilute solutions

    NASA Technical Reports Server (NTRS)

    Bauman, A. J.; Weetal, H. H.; Weliky, N.

    1966-01-01

    Column chromatographic method uses new metal chelating resins for recovering heavy-metal ions from highly dilute solutions. The absorbed heavy-metal cations may be removed from the chelating resins by acid or base washes. The resins are reusable after the washes are completed.

  9. Chelation Treatment for Autism Spectrum Disorders: A Systematic Review

    ERIC Educational Resources Information Center

    Davis, Tonya N.; O'Reilly, Mark; Kang, Soyeon; Lang, Russell; Rispoli, Mandy; Sigafoos, Jeff; Lancioni, Giulio; Copeland, Daelynn; Attai, Shanna; Mulloy, Austin

    2013-01-01

    Chelation treatment is used to eliminate specific metals from the body, such as mercury. It has been hypothesized that mercury poisoning may be a factor in autism and data suggest that perhaps 7% of individuals with autism spectrum disorder (ASD) have received chelation treatment. It would therefore seem timely to review studies investigating the

  10. Clawing Back: Broadening the Notion of Metal Chelators in Medicine

    PubMed Central

    Franz, Katherine J.

    2013-01-01

    The traditional notion of chelation therapy is the administration of a chemical agent to remove metals from the body. But formation of a metal-chelate can have biological ramifications that are much broader than metal elimination. Exploring these other possibilities could lead to pharmacological interventions that alter the concentration, distribution, or reactivity of metals in targeted ways for therapeutic benefit. This review highlights recent examples that showcase four general strategies of using principles of metal chelation in medicinal contexts beyond the traditional notion of chelation therapy. These strategies include altering metal biodistribution, inhibiting specific metalloenzymes associated with disease, enhancing the reactivity of a metal complex to promote cytotoxicity, and conversely, passivating the reactivity of metals by site-activated chelation to prevent cytotoxicity. PMID:23332666

  11. Chelating versatility of toxic metal resistant microorganisms

    SciTech Connect

    Premuzic, E.T.; Lin, M.

    1985-05-01

    Thorium- and uranium-resistant strains of Pseudomonas aeruginosa when grown in high concentration of these metals (100 to 1000 ppM) in citrate- or succinate-containing media produce several chelating agents. Crude extracts of the metal-induced products, when tested for their toxicity and decorporation potential from mammalian tissues have shown that their efficiency is comparable to DTPA (Diethylene triamine pentaacetic acid) and DFOA (Desferrioxamine). Washed biomass of P. aeruginosa also bioaccumulates heavy metals. Bioaccumulation is selective and several microorganisms have been tested for selective adsorption of uranium, thorium, cobalt, chromium, manganese, tin, and platinum. The results have shown that P. aeruginosa CSU has a preference for uranium, while P. aeruginosa PAO-1 and P. fluorescens exhibit a preference for thorium, and Aspergillus niger is selective for chromium and thorium. 8 refs., 3 figs., 2 tabs.

  12. Severe Endobronchial Inflammation Induced by Aspiration of a Ferrous Sulfate Tablet.

    PubMed

    Lim, Sang Youn; Sohn, Sung Birm; Lee, Jung Min; Lee, Ji Ae; Chung, Sangmi; Kim, Junga; Choi, Juwhan; Kim, Sehwa; Yoo, Ah Young; Roh, Jong Ah; Park, Haein; Kim, Won Shik; Sim, Jae Kyeom; Shim, Jae Jeong; Min, Kyung Hoon

    2016-01-01

    Iron supplements such as ferrous sulfate tablets are usually used to treat iron-deficiency anemia in some elderly patients with primary neurologic disorders or decreased gag reflexes due to stroke, senile dementia, or parkinsonism. While the aspiration of ferrous sulfate is rarely reported, it is a potentially life-threatening condition that can lead to airway necrosis and bronchial stenosis. A detailed history and high suspicion of aspiration are required to avoid delays in diagnosis and treatment. The diagnosis can be confirmed by bronchoscopic examination and a tissue biopsy. Early removal of the aspirated tablet prevents acute complications, such as bronchial necrosis, hemoptysis, and lobar consolidation. Tablet removal is also necessary to prevent late bronchial stenosis. We presented the first case in Korea of a ferrous sulfate tablet aspiration that induced severe endobronchial inflammation. PMID:26770233

  13. Severe Endobronchial Inflammation Induced by Aspiration of a Ferrous Sulfate Tablet

    PubMed Central

    Lim, Sang Youn; Sohn, Sung Birm; Lee, Jung Min; Lee, Ji Ae; Chung, Sangmi; Kim, Junga; Choi, Juwhan; Kim, Sehwa; Yoo, Ah Young; Roh, Jong Ah; Park, Haein; Kim, Won Shik; Sim, Jae Kyeom; Shim, Jae Jeong

    2016-01-01

    Iron supplements such as ferrous sulfate tablets are usually used to treat iron-deficiency anemia in some elderly patients with primary neurologic disorders or decreased gag reflexes due to stroke, senile dementia, or parkinsonism. While the aspiration of ferrous sulfate is rarely reported, it is a potentially life-threatening condition that can lead to airway necrosis and bronchial stenosis. A detailed history and high suspicion of aspiration are required to avoid delays in diagnosis and treatment. The diagnosis can be confirmed by bronchoscopic examination and a tissue biopsy. Early removal of the aspirated tablet prevents acute complications, such as bronchial necrosis, hemoptysis, and lobar consolidation. Tablet removal is also necessary to prevent late bronchial stenosis. We presented the first case in Korea of a ferrous sulfate tablet aspiration that induced severe endobronchial inflammation. PMID:26770233

  14. Chelation in metal intoxication XXI: chelation in lead intoxication during vitamin B complex deficiency

    SciTech Connect

    Not Available

    1986-09-01

    The vitamin B-complex deficiency increases the vulnerability to neuro- and systemic toxicity of Pb in young rats. Thus, the nutritional status of vitamins like that of protein or minerals seems to influence the etiology of Pb toxicity and may be expected to affect the response toward Pb chelators. 2,3 dimercaptosuccinic acid (DMSA) and N-(2-hydroxyethyl) ethylene-diamine triacetic acid (HEDTA) have been found to be effective antidotes to Pb intoxication. In the present study, these selective metal chelating agents were compared for their ability to reduce the body burden of Pb and restore the altered biochemical parameters in young developing Pb intoxicated rats maintained on normal or vitamin B-complex deficient diet. The investigation was aimed to suggest suitable prophylaxis of Pb poisoning prevalent among children who may also be suffering from vitamin deficiency in developing and poor countries.

  15. Influence of chelate ring interactions on copper(II) chelate stability studied by connectivity index functions.

    PubMed

    Milicević, Ante; Raos, Nenad

    2008-08-21

    Linear models for estimation of the first (K1), second (K2), and overall stability constant (beta2) based on the valence connectivity index of the third order ((3)chi(v)) were developed and checked on four sets of copper(II) chelates (with diamines, N-alkylated glycines, and naturally occurring amino acids, including their mixed complexes). Univariate models were valid when log K1 and log K2 values were linearly correlated, i.e., when there was no interaction between chelate rings. The univariate models proved applicable for estimation of all three stability constants of complexes with diamines and N-alkylated glycines, but for complexes with amino acids additional terms were needed (bivariate models). Models reproduced stability constants with an error usually less than 0.3 log K units. PMID:18665572

  16. Chelating ionic liquids for reversible zinc electrochemistry.

    PubMed

    Kar, Mega; Winther-Jensen, Bjorn; Forsyth, Maria; MacFarlane, Douglas R

    2013-05-21

    Advanced, high energy-density, metal-air rechargeable batteries, such as zinc-air, are of intense international interest due to their important role in energy storage applications such as electric and hybrid vehicles, and to their ability to deal with the intermittency of renewable energy sources such as solar and wind. Ionic liquids offer a number of ideal thermal and physical properties as potential electrolytes in such large-scale energy storage applications. We describe here the synthesis and characterisation of a family of novel "chelating" ILs designed to chelate and solubilize the zinc ions to create electrolytes for this type of battery. These are based on quaternary alkoxy alkyl ammonium cations of varying oligo-ether side chains and anions such as p-toluene sulfonate, bis(trifluoromethylsulfonyl)amide and dicyanoamides. This work shows that increasing the ether chain length in the cation from two to four oxygens can increase the ionic conductivity and reduce the melting point from 67 C to 15 C for the tosylate system. Changing the anion also plays a significant role in the nature of the zinc deposition electrochemistry. We show that zinc can be reversibly deposited from [N(222(20201))][NTf2] and [N(222(202020201))][NTf2] beginning at -1.4 V and -1.7 V vs. SHE, respectively, but not in the case of tosylate based ILs. This indicates that the [NTf2] is a weaker coordinating anion with the zinc cation, compared to the tosylate anion, allowing the coordination of the ether chain to dominate the behavior of the deposition and stripping of zinc ions. PMID:23558696

  17. Changes of ferrous iron and its transporters after intracerebral hemorrhage in rats

    PubMed Central

    Wang, Gaiqing; Shao, Anwen; Hu, Weimin; Xue, Fang; Zhao, Hongping; Jin, Xiaojie; Li, Guanglai; Sun, Zhitang; Wang, Li

    2015-01-01

    Objective: Ferrous iron is a major source inducing oxidative stress after intracerebral hemorrhage (ICH). Divalent metal transporter1 (DMT1) is the important and well-known plasma membrane transport protein which was proved to be involved in the transport of free ferrous iron in mammals. Ferroportin 1 (FPN1) is the unique exporter of ferrous iron from mammalian cells. The role of DMT1 and FPN1 in brain after ICH is still not elucidated. Therefore, we measure the expression of DMT1 and FPN1, to explore the correlations between ferrous iron and its specific transporters after ICH. Methods: Ninety-six Sprague-Dawley rats received intra-striatal infusions of 0.5 U type IV collagenase to establish ICH model. Ferrous iron content in brain was determined using Turnbulls method. DMT1 and FPN1 expression were examined by immunohistochemical staining and Real-Time quantitative polymerase chain reaction (RT-PCR). With the use of confocal laser microscopy, we determined the colocalization of DMT1 and FPN1 at 1, 3, 7 and 14 days after ICH. Results: Ferrous iron deposition was shown in the perihematomal zone as early as 1 day after ICH; it reached a peak after 7 days and was not elevated within 14 days following ICH. The expression of the DMT1 upregulated and reached to peak at day 7 after ICH. FPN1 reached a plateau at 3 days post-ICH. Expression levels of DMT1 and FPN1 were in parallel with ferrous iron deposition. There was a positive correlation between FPN1 and DMT1. DMT1 mainly localized in the cytoplasm of glias and neurons. FPN1 were mostly distributed on the membrane of endothelial cells and glias. Confocal microscope showed that DMT1 colocalized with FPN1. Conclusions: DMT1 and FPN1 are positively influenced by ferrous iron status in brain after ICH. DMT1 and FPN1 attenuate iron overload after ICH via increasing transmembrane iron export. PMID:26617777

  18. Development of an intelligent control system for ferrous iron oxidation by Thiobacillus ferrooxidans

    SciTech Connect

    Light, M.D.; Torma, A.E.; Cordes, G.A.

    1991-01-01

    An intelligent control system (ICS) is being developed for ferrous iron oxidation by Thiobacillus ferroxidans. The ICS provides compterized data acquisition and control of process variables (temperature, Eh, pH, dissolved oxygen and carbon dioxide concentrations, and dilution rate) to maintain the ferrous iron oxidation at the highest possible rate. The ICS uses fuzzy logic for analysis of data inputs and implementation of control strategies. This paper provides preliminary information on the development of the ICS and its operation. 17 refs., 3 figs.

  19. Chelation: Harnessing and Enhancing Heavy Metal Detoxification—A Review

    PubMed Central

    Sears, Margaret E.

    2013-01-01

    Toxic metals such as arsenic, cadmium, lead, and mercury are ubiquitous, have no beneficial role in human homeostasis, and contribute to noncommunicable chronic diseases. While novel drug targets for chronic disease are eagerly sought, potentially helpful agents that aid in detoxification of toxic elements, chelators, have largely been restricted to overt acute poisoning. Chelation, that is multiple coordination bonds between organic molecules and metals, is very common in the body and at the heart of enzymes with a metal cofactor such as copper or zinc. Peptides glutathione and metallothionein chelate both essential and toxic elements as they are sequestered, transported, and excreted. Enhancing natural chelation detoxification pathways, as well as use of pharmaceutical chelators against heavy metals are reviewed. Historical adverse outcomes with chelators, lessons learned in the art of using them, and successes using chelation to ameliorate renal, cardiovascular, and neurological conditions highlight the need for renewed attention to simple, safe, inexpensive interventions that offer potential to stem the tide of debilitating, expensive chronic disease. PMID:23690738

  20. Synthetic and natural iron chelators: therapeutic potential and clinical use

    PubMed Central

    Hatcher, Heather C; Singh, Ravi N; Torti, Frank M; Torti, Suzy V

    2013-01-01

    Iron-chelation therapy has its origins in the treatment of iron-overload syndromes. For many years, the standard for this purpose has been deferoxamine. Recently, considerable progress has been made in identifying synthetic chelators with improved pharmacologic properties relative to deferoxamine. Most notable are deferasirox (Exjade®) and deferiprone (Ferriprox®), which are now available clinically. In addition to treatment of iron overload, there is an emerging role for iron chelators in the treatment of diseases characterized by oxidative stress, including cardiovascular disease, atherosclerosis, neurodegenerative diseases and cancer. While iron is not regarded as the underlying cause of these diseases, it does play an important role in disease progression, either through promotion of cellular growth and proliferation or through participation in redox reactions that catalyze the formation of reactive oxygen species and increase oxidative stress. Thus, iron chelators may be of therapeutic benefit in many of these conditions. Phytochemicals, many of which bind iron, may also owe some of their beneficial properties to iron chelation. This review will focus on the advances in iron-chelation therapy for the treatment of iron-overload disease and cancer, as well as neurodegenerative and chronic inflammatory diseases. Established and novel iron chelators will be discussed, as well as the emerging role of dietary plant polyphenols that effectively modulate iron biochemistry. PMID:21425984

  1. Nanoparticle and Iron Chelators as a Potential Novel Alzheimer Therapy

    PubMed Central

    Liu, Gang; Men, Ping; Perry, George; Smith, Mark A.

    2010-01-01

    Current therapies for Alzheimer disease (AD) such as the acetylcholinesterase inhibitors and the latest NMDA receptor inhibitor, Namenda, provide moderate symptomatic delay at various stages of the disease, but do not arrest the disease progression or bring in meaningful remission. New approaches to the disease management are urgently needed. Although the etiology of AD is largely unknown, oxidative damage mediated by metals is likely a significant contributor since metals such as iron, aluminum, zinc, and copper are dysregulated and/or increased in AD brain tissue and create a pro-oxidative environment. This role of metal ion-induced free radical formation in AD makes chelation therapy an attractive means of dampening the oxidative stress burden in neurons. The chelator desferrioxamine, FDA approved for iron overload, has shown some benefit in AD, but like many chelators, it has a host of adverse effects and substantial obstacles for tissue-specific targeting. Other chelators are under development and have shown various strengths and weaknesses. Here, we propose a novel system of chelation therapy through the use of nanoparticles. Nanoparticles conjugated to chelators show unique ability to cross the blood–brain barrier (BBB), chelate metals, and exit through the BBB with their corresponding complexed metal ions. This method may provide a safer and more effective means of reducing the metal load in neural tissue, thus attenuating the harmful effects of oxidative damage and its sequelae. Experimental procedures are presented in this chapter. PMID:20013176

  2. [Dithiols as chelators. A cause of bullous skin reactions].

    PubMed

    Storim, J; Stoevesandt, J; Anders, D; Kneitz, H; Brcker, E-B; Trautmann, A

    2011-03-01

    Chelation therapy with (RS)-2,3-Bis(sulfonyl)propane-1-sulfonic acid (DMPS) after an occupational lead exposure led to the development of a severe bullous drug eruption. Skin tests and histology/immunohistology of the test reactions indicated a T-cell-mediated immune response against DMPS. Metal-binding thiol groups as in DMPS are chemically highly reactive and therefore effectively mediate the development of immunogenic hapten (DMPS)-protein complexes. Therefore, the pharmacological effects and sensitization potential of dithiols are tightly connected. Cross-reactivity of DMPS to other chelators like D-penicillamine is possible; the indications for chelation therapy should be weighed carefully. PMID:20945055

  3. Use of gadolinium chelates in MR imaging of the spine.

    PubMed

    Bradley, W G

    1997-01-01

    Spinal disease can be divided into intramedullary, extramedullary-intradural, and extradural compartments. In the cord (intramedullary compartment), gadolinium chelates are useful to diagnose primary and metastatic tumors, inflammation, and demyelination, and to evaluate syringomyelia when a Chiari I malformation is not present. In the extramedullary-intradural compartment, gadolinium chelates are useful for the diagnosis of drop metastases, meningiomas, and schwannomas. In the extradural compartment, gadolinium chelates are most useful to distinguish recurrent disc herniation from epidural fibrosis in the postoperative back and may be useful to diagnosis the soft tissue component of osseous metastases. PMID:9039592

  4. IN SITU CR(VI) TREATMENT USING A FERROUS IRON-BASED REDUCTANT

    EPA Science Inventory

    Laboratory and field studies were conducted to evaluate the performance of a ferrous sulfate/ sodium hydrosulfite (dithionite) reductant blend in treating a hexavalent chromium (Cr(VI)) source area and Cr(VI) dissolved phase plume at a former industrial site in Charleston, South ...

  5. COMBINATION LIMESTONE-LIME NEUTRALIZATION OF FERROUS IRON ACID MINE DRAINAGE

    EPA Science Inventory

    Studies were conducted on ferrous-iron acid mine drainage (AMD) treatment by a two-step neutralization process in which rock-dust limestone was mixed with the influent AMD and then hydrated lime was added in a polishing reactor. This combination treatment process resulted in reag...

  6. 46 CFR 148.04-13 - Ferrous metal borings, shavings, turnings, or cuttings (excluding stainless steel).

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Ferrous metal borings, shavings, turnings, or cuttings (excluding stainless steel). 148.04-13 Section 148.04-13 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) DANGEROUS CARGOES CARRIAGE OF SOLID HAZARDOUS MATERIALS IN BULK Special Additional Requirements for Certain Material §...

  7. Energy conservation and efficiency in Giprokoks designs at Ukrainian ferrous-metallurgical enterprises

    SciTech Connect

    M.I. Fal'kov

    2009-07-15

    Energy conditions at Ukrainian ferrous-metallurgical enterprises are analyzed. Measures to boost energy conservation and energy efficiency are proposed: specifically, the introduction of systems for dry slaking of coke; and steam-gas turbines that employ coke-oven gas or a mixture of gases produced at metallurgical enterprises. Such turbines may be built from Ukrainian components.

  8. ANALYSIS OF FERRIC AND FERROUS IONS IN SOIL EXTRACTS BY ION CHROMATOGRAPHY

    EPA Science Inventory

    A method using ion chromatography (IC) for the analysis of ferrous (Fe 2+) and ferric (Fe 3+) ions in soil extracts has been developed. This method uses an ion exchange column with detection at 520 nm after post-column derivatization. Selectivity is achieved by using an anionic...

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

    PubMed

    Xenidis, Anthimos; Stouraiti, Christina; Papassiopi, Nymphodora

    2010-05-15

    The chemical immobilization of Pb and As in contaminated soil from Lavrion, Greece, using monocalcium phosphate and ferrous sulfate as stabilizing agents was investigated. Monocalcium phosphate was added to contaminated soil at PO(4) to Pb molar ratios equal to 0, 0.5, 1, 1.5 and 2.5, whereas ferrous sulfate was added at Fe to As molar ratios equal to 0, 2.5, 5, 10 and 20. Phosphates addition to contaminated soil decreased Pb leachability, but resulted in significant mobilization of As. Simultaneous immobilization of Pb and As was obtained only when soil was treated with mixtures of phosphates and ferrous sulfate. Arsenic uptake by plants was also seen to increase when soil was treated only with phosphates, but co-addition of ferrous sulfate was efficient in maintaining As phytoaccumulation at low levels. The addition of at least 1.5M/M phosphates and 10M/M iron sulfate to soil reduced the dissolved levels of Pb and As in the water extracts to values in compliance with the EU drinking water standards. However, both additives contributed in the acidification of soil, decreasing pH from 7.8 to values as low as 5.6 and induced the mobilization of pH sensitive elements, such as Zn and Cd. PMID:20116921

  10. Application of ferrous hydrogen peroxide for treatment of DSD-acid manufacturing process wastewater.

    PubMed

    Zhu, W; Yang, Z; Wang, L

    2001-06-01

    A pretreatment method for the biological treatment of wastewater from 4,4'-diaminostilbene-2,2'-disulfonic acid (DSD-acid) manufacturing processes, a refractory dye intermediate wastewater, based on combined ferrous hydrogen peroxide oxidation and coagulation-flocculation, was developed. When the wastewater was treated with ferrous hydrogen peroxide oxidation ([Fe2+] = 2.7 mmol/L, [H2O2] = 0.21 mol/L) after a flocculation using an organic flocculant TS-1 at a dosage of 3 g/L, the overall COD and color removals were 64 and 62%, respectively. BOD5/COD value of the effluent was 0.3. Ferrous hydrogen peroxide oxidation treatment can reduce the solubility of organic molecules with sulfonic group and increase the efficiency of coagulation treatment. The COD and color removals were both more than 90% when FeCl3 was used as the coagulation (dosages of two-step coagulation were 0.031 and 0.012 mol/L respectively) after a ferrous hydrogen peroxide oxidation pretreatment at a H2O2 dosage of 0.06 mol/L. PMID:11337859

  11. ORGANIC EMISSIONS FROM FERROUS METALLURGICAL INDUSTRIES: COMPILATION OF EMISSION FACTORS AND CONTROL TECHNOLOGIES

    EPA Science Inventory

    The report gives results of a review and analysis of the information and data available in the public domain on organic emissions from the ferrous metallurgy industry, specifically the iron and steel, iron foundry, and ferroalloy industries. Emission sources and information gaps ...

  12. Sound Velocities for Ferrous Periclase Through the High Spin - Low Spin Transition

    NASA Astrophysics Data System (ADS)

    Brown, J. M.; Crowhurst, J.; Goncharov, A.; Zaug, J.; Jacobsen, S. D.

    2006-12-01

    We report the first determination of elastic wave velocities in (Mg,Fe)O with 6% iron through the high spin to low spin (HS-LS) transition (between 40 and 60 GPa). We obtained elastic wave velocities for ferrous periclase using impulsively stimulated light scattering in a diamond anvil cell with noble gas pressure media. Since discovery of the HS-LS transition in iron-bearing lower mantle phases, the effect of the transition on seismic properties has loomed as a significant issue in understanding the compositional state of the mantle. In our analysis of recent data and theory, we note that the transition is non-first order and relatively insensitive to iron compositions for Fe/(Fe+Mg) less than about 20%. The pressure of transition is largely temperature independent but is significantly broadened at high temperature. Our model for the transition (based on theory and prior experiments and including a frequency dependent term associated with the spin-flip transition rate) is consistent with our data. Predicted seismic profiles for the lower mantle based on this model differ significantly from profiles using high-spin ferrous periclase properties. Several interpretations are possible. (1) Ferrous periclase is not a significant phase in the lower mantle or (2) the equilibrium HS-LS transition in ferrous periclase is suppressed in the lower mantle to perhaps higher pressures.

  13. ELECTRODE MEASUREMENT OF REDOX POTENTIAL IN ANAEROBIC FERRIC/FERROUS CHLORIDE SYSTEMS

    EPA Science Inventory

    The behaviour of two inert redox electrodes (Pt and wax-impregnated graphite) was investigated in anaerobic ferrous and ferric chloride solutions in order to establish if these electrodes respond to the Fe3+/Fe2+ couple in a Nernstian manner. A new method fo...

  14. ELECTRODE MEASUREMENT OF REDOX POTENTIAL IN ANAEROBIC FERRIC/FERROUS CHLORIDE SYSTEMS

    EPA Science Inventory

    The behavior of two inert redox electrodes (Pt and wax-impregnated graphite) was investigated in anaerobic ferrous and ferric chloride solutions in order to establish if these electrodes respond to the FE3/Fe2+ couple in a Nernstian nanner. ew method for determining dissolved fer...

  15. Effects of adding glycerol and sucrose to ferrous xylenol orange hydrogel

    NASA Astrophysics Data System (ADS)

    Jordan, Kevin; Sekimoto, Masaya

    2010-11-01

    Glycerol and sucrose were substituted up to 40% by mass for water in ferrous xylenol gelatin hydrogel (FX). Both materials increased the refractive index of the aqueous component of the gels and lowered the optical scatter coefficient. Diffusion of the FX products was reduced 3-fold at 40% substitution levels. The radiation response was more stable with glycerol.

  16. Ceric and ferrous dosimeters show precision for 50-5000 rad range

    NASA Technical Reports Server (NTRS)

    Frigerio, N. A.; Henry, V. D.

    1968-01-01

    Ammonium thiocyanate, added to the usual ferrous sulfate dosimeter solution, yielded a very stable, precise and temperature-independent system eight times as sensitive as the classical Fricke system in the 50 to 5000 rad range. The ceric dosimeters, promising for use in mixed radiation fields, respond nearly independently of LET.

  17. 76 FR 31357 - Agency Information Collection Activities: Comment Request for the Ferrous Metals Surveys

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-31

    ... Comments On February 22, 2011, we published a Federal Register Notice (76 FR 9810) announcing that we would... Metals Surveys AGENCY: U.S. Geological Survey (USGS), Interior. ACTION: Notice of a revision of a... requirements for the Ferrous Metals Surveys. This collection consists of 17 forms. This notice provides...

  18. Chelating ligands for nanocrystals' surface functionalization.

    PubMed

    Querner, Claudia; Reiss, Peter; Bleuse, Joël; Pron, Adam

    2004-09-22

    A new family of ligands for the surface functionalization of CdSe nanocrystals is proposed, namely alkyl or aryl derivatives of carbodithioic acids (R-C(S)SH). The main advantages of these new ligands are as follows: they nearly quantitatively exchange the initial surface ligands (TOPO) in very mild conditions; they significantly improve the resistance of nanocrystals against photooxidation because of their ability of strong chelate-type binding to metal atoms; their relatively simple preparation via Grignard intermediates facilitates the development of new bifunctional ligands containing, in addition to the anchoring carbodithioate group, a second function, which enables the grafting of molecules or macromolecules of interest on the nanocrystal surface. To give an example of this approach, we report, for the first time, the grafting of an electroactive oligomer from the polyaniline family-aniline tetramer-on CdSe nanocrystals after their functionalization with 4-formyldithiobenzoic acid. The grafting proceeds via a condensation reaction between the aldehyde group of the ligand and the terminal primary amine group of the tetramer. The resulting organic/inorganic hybrid exhibits complete extinction of the fluorescence of its constituents, indicating efficient charge or energy transfer between the organic and the inorganic semiconductors. PMID:15366904

  19. Radiation-chemical and MR studies of aqueous agarose gels containing ferrous ions

    SciTech Connect

    Leghrous, A.A.

    1989-01-01

    Aqueous agarose gels containing ferrous ions, in 0.05 N sulfuric acid have been studied after irradiation with 6-18 MeV electrons or {sup 137}Cs {gamma}-rays. Such gels can sustain a radiolytic chain reaction, producing Fe{sup 3+} with G (Fe{sup 3+})-values up to 100 having been observed. The Fe{sup 3+} production is independent of dose rate between 0.434 and 3.74 Gy min{sup {minus}1}. Dissolved oxygen is needed to maintain the chain reaction, and initial ferric yields are increased if the gel is oxygen saturated or if the ferrous concentration is decreased below 1 mM. The oxidation of ferrous to ferric alters the magnetic moment of the ion and its electron spin relaxation time, which in turn affects its ability to promote proton spin relaxation rates. Longitudinal proton magnetic relaxation rates are increased in proportion to ferric production, permitting visualization of dose levels in these gels by magnetic resonance imaging (MRI) techniques. Non-uniform dose distribution images of electron irradiated ferrous/agarose (FA) systems have been obtained using MRI. Images of radiation doses surrounding capillary tubes filled with radioactive material embedded in PA systems have also been obtained. In this work, another new method of using the ferrous/agarose gel system doped with xylenol orange to visualize the radiation dose distribution directly by eye has been developed. The color change developed depends both quantitatively and qualitatively on the concentrations of solutes in the gel.

  20. Strategies for the preparation of bifunctional gadolinium(III) chelators

    PubMed Central

    Frullano, Luca; Caravan, Peter

    2012-01-01

    The development of gadolinium chelators that can be easily and readily linked to various substrates is of primary importance for the development high relaxation efficiency and/or targeted magnetic resonance imaging (MRI) contrast agents. Over the last 25 years a large number of bifunctional chelators have been prepared. For the most part, these compounds are based on ligands that are already used in clinically approved contrast agents. More recently, new bifunctional chelators have been reported based on complexes that show a more potent relaxation effect, faster complexation kinetics and in some cases simpler synthetic procedures. This review provides an overview of the synthetic strategies used for the preparation of bifunctional chelators for MRI applications. PMID:22375102

  1. 3-hydroxy-2(1H)-pyridinone chelating agents

    DOEpatents

    Raymond, Kenneth (Berkeley, CA); Xu, Jide (Berkeley, CA)

    1999-01-01

    Disclosed is a series of improved chelating agents and the chelates formed from these agents, which are highly effective upon both injection and oral administration. Several of the most effective are of low toxicity. These chelating agents incorporate within their structure 3-hydroxy-2-pyridinone (3,2-HOPO) moieties with a substituted carbamoyl group ortho to the hydroxy group of the hydroxypyridinone ring. The electron-withdrawing carbamoyl group increases the acidity, as well as the chemical stability towards oxidation and reduction, of the hydroxypyridinones. In the metal complexes of the chelating agents, the amide protons form very strong hydrogen bonds with the adjacent HOPO oxygen donor, making these complexes very stable at physiological conditions. The terminal N-substituents provide a certain degree of lipophilicity to the 3,2-HOPO, increasing oral activity.

  2. 3-hydroxy-2(1H)-pyridinone chelating agents

    DOEpatents

    Raymond, K.; Xu, J.

    1999-04-06

    Disclosed is a series of improved chelating agents and the chelates formed from these agents, which are highly effective upon both injection and oral administration. Several of the most effective are of low toxicity. These chelating agents incorporate within their structure 3-hydroxy-2-pyridinone (3,2-HOPO) moieties with a substituted carbamoyl group ortho to the hydroxy group of the hydroxypyridinone ring. The electron-withdrawing carbamoyl group increases the acidity, as well as the chemical stability towards oxidation and reduction, of the hydroxypyridinones. In the metal complexes of the chelating agents, the amide protons form very strong hydrogen bonds with the adjacent HOPO oxygen donor, making these complexes very stable at physiological conditions. The terminal N-substituents provide a certain degree of lipophilicity to the 3,2-HOPO, increasing oral activity. 2 figs.

  3. Metal chelate process to remove pollutants from fluids

    DOEpatents

    Chang, Shih-Ger T. (El Cerrito, CA)

    1994-01-01

    The present invention relates to improved methods using an organic iron chelate to remove pollutants from fluids, such as flue gas. Specifically, the present invention relates to a process to remove NO.sub.x and optionally SO.sub.2 from a fluid using a metal ion (Fe.sup.2+) chelate wherein the ligand is a dimercapto compound wherein the --SH groups are attached to adjacent carbon atoms (HS--C--C--SH) or (SH--C--CCSH) and contain a polar functional group so that the ligand of DMC chelate is water soluble. Alternatively, the DMC' is covalently attached to a water insoluble substrate such as a polymer or resin, e.g., polystyrene. The chelate is regenerated using electroreduction or a chemical additive. The dimercapto compound bonded to a water insoluble substrate is also useful to lower the concentration or remove hazardous metal ions from an aqueous solution.

  4. Comparing potential copper chelation mechanisms in Parkinson's disease protein

    NASA Astrophysics Data System (ADS)

    Rose, Frisco; Hodak, Miroslav; Bernholc, Jerry

    2011-03-01

    We have implemented the nudged elastic band (NEB) as a guided dynamics framework for our real-space multigrid method of DFT-based quantum simulations. This highly parallel approach resolves a minimum energy pathway (MEP) on the energy hypersurface by relaxing intermediates in a chain-of-states. As an initial application we present an investigation of chelating agents acting on copper ion bound to α -synuclein, whose misfolding is implicated in Parkinson's disease (PD). Copper ions are known to act as highly effective misfolding agents in a-synuclein and are thus an important target in understanding PD. Furthermore, chelation therapy has shown promise in the treatment of Alzheimer's and other neuro-degenerative diseases with similar metal-correlated pathologies. At present, our candidate chelating agents include nicotine, curcumin and clioquinol. We examine their MEP activation barriers in the context of a PD onset mechanism to assess the viability of various chelators for PD remediation.

  5. Minding Metals: Tailoring Multifunctional Chelating Agents for Neurodegenerative Disease

    PubMed Central

    Perez, Lissette R.; Franz, Katherine J.

    2010-01-01

    Neurodegenerative diseases like Alzheimer's and Parkinson's disease are associated with elevated levels of iron, copper, and zinc and consequentially high levels of oxidative stress. Given the multifactorial nature of these diseases, it is becoming evident that the next generation of therapies must have multiple functions to combat multiple mechanisms of disease progression. Metal-chelating agents provide one such function as an intervention for ameliorating metal-associated damage in degenerative diseases. Targeting chelators to adjust localized metal imbalances in the brain, however, presents significant challenges. In this perspective, we focus on some noteworthy advances in the area of multifunctional metal chelators as potential therapeutic agents for neurodegenerative diseases. In addition to metal chelating ability, these agents also contain features designed to improve their uptake across the blood-brain barrier, increase their selectivity for metals in damage-prone environments, increase antioxidant capabilities, lower Aβ peptide aggregation, or inhibit disease-associated enzymes such as monoamine oxidase and acetylcholinesterase. PMID:20162187

  6. An Evaluation of the Chelating Agent EDDS for Marigold Production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aminopolycarboxylic acid (APCA) ligands (chelating agents) like ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DTPA) are commonly used in soluble fertilizers to supply copper (Cu), iron (Fe), manganese (Mn), and/or zinc (Zn) to plants. The offsite runoff and contamina...

  7. Metal chelate process to remove pollutants from fluids

    DOEpatents

    Chang, S.G.T.

    1994-12-06

    The present invention relates to improved methods using an organic iron chelate to remove pollutants from fluids, such as flue gas. Specifically, the present invention relates to a process to remove NO[sub x] and optionally SO[sub 2] from a fluid using a metal ion (Fe[sup 2+]) chelate wherein the ligand is a dimercapto compound wherein the --SH groups are attached to adjacent carbon atoms (HS--C--C--SH) or (SH--C--CCSH) and contain a polar functional group so that the ligand of DMC chelate is water soluble. Alternatively, the DMC is covalently attached to a water insoluble substrate such as a polymer or resin, e.g., polystyrene. The chelate is regenerated using electroreduction or a chemical additive. The dimercapto compound bonded to a water insoluble substrate is also useful to lower the concentration or remove hazardous metal ions from an aqueous solution. 26 figures.

  8. Electrokinetic remediation of concrete: effect of chelating agents.

    PubMed

    Popov, K; Glazkova, I; Yachmenev, V; Nikolayev, A

    2008-05-01

    Contamination of concrete at various nuclear power plants and spent nuclear fuel reprocessing facilities by radionuclides represents a significant problem for the world's nuclear power industries and nuclear waste management. The present publication summarizes the most recently published data on Electrokinetic Remediation (EK) of various concrete installations and advantageous effects of the combination of EK with different chelating agents. The specific aspects of decontamination of concrete and mortar surfaces are analyzed, such as: (a) effect of chelating agents (EDTA, citric acid), (b) effect of the zeta-potential (zeta) of concrete surface, (c) effects of sorption and complex formation equilibrium, and (d) specific advantages and problems of the electrokinetic decontamination process. The results of laboratory and in situ tests of chelating agent assisted EK removal of radionuclides are reported. It is demonstrated that the correct combination of EK with specific chelating agents can be effectively employed for decontamination of concrete surfaces. PMID:18313182

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

    PubMed

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

    2016-01-01

    Calcium oxide was added into ferrous ion oxidation system in the presence of Acidithiobacillus ferrooxidans at concentrations of 0-4.00 g/L. The pH, ferrous ion oxidation efficiency, total iron precipitation efficiency, and phase of the solid minerals harvested from different treatments were investigated during the ferrous ion oxidation process. In control check (CK) system, pH of the solution decreased from 2.81 to 2.25 when ferrous ions achieved complete oxidation after 72 h of Acidithiobacillus ferrooxidans incubation without the addition of calcium oxide, and total iron precipitation efficiency reached 20.2%. Efficiency of ferrous ion oxidation and total iron precipitation was significantly improved when the amount of calcium oxide added was ≤1.33 g/L, and the minerals harvested from systems were mainly a mixture of jarosite and schwertmannite. For example, the ferrous ion oxidation efficiency reached 100% at 60 h and total iron precipitation efficiency was increased to 32.1% at 72 h when 1.33 g/L of calcium oxide was added. However, ferrous ion oxidation and total iron precipitation for jarosite and schwertmannite formation were inhibited if the amount of calcium oxide added was above 2.67 g/L, and large amounts of calcium sulfate dihydrate were generated in systems. PMID:27003087

  10. Chelated Ruthenium Catalysts for Z-Selective Olefin Metathesis

    PubMed Central

    Endo, Koji; Grubbs, Robert H.

    2011-01-01

    We report the development of ruthenium-based metathesis catalysts with chelating N-heterocyclic carbene (NHC) ligands which catalyze highly Z-selective olefin metathesis. A very simple and convenient synthetic procedure of such a catalyst has been developed. An intramolecular C-H bond activation of the NHC ligand, which is promoted by anion ligand substitution, forms the appropriate chelate for stereo- controlled olefin metathesis. PMID:21563826

  11. Extraction of metals using supercritical fluid and chelate forming legand

    DOEpatents

    Wai, Chien M.; Laintz, Kenneth E.

    1998-01-01

    A method of extracting metalloid and metal species from a solid or liquid material by exposing the material to a supercritical fluid solvent containing a chelating agent is described. The chelating agent forms chelates that are soluble in the supercritical fluid to allow removal of the species from the material. In preferred embodiments, the extraction solvent is supercritical carbon dioxide and the chelating agent is a fluorinated .beta.-diketone. In especially preferred embodiments the extraction solvent is supercritical carbon dioxide, and the chelating agent comprises a fluorinated .beta.-diketone and a trialkyl phosphate, or a fluorinated .beta.-diketone and a trialkylphosphine oxide. Although a trialkyl phosphate can extract lanthanides and actinides from acidic solutions, a binary mixture comprising a fluorinated .beta.-diketone and a trialkyl phosphate or a trialkylphosphine oxide tends to enhance the extraction efficiencies for actinides and lanthanides. The method provides an environmentally benign process for removing contaminants from industrial waste without using acids or biologically harmful solvents. The method is particularly useful for extracting actinides and lanthanides from acidic solutions. The chelate and supercritical fluid can be regenerated, and the contaminant species recovered, to provide an economic, efficient process.

  12. Iron chelators ICL670 and 311 inhibit HIV-1 transcription

    SciTech Connect

    Debebe, Zufan; Ammosova, Tatyana; Jerebtsova, Marina; Kurantsin-Mills, Joseph; Niu, Xiaomei; Charles, Sharroya; Richardson, Des R.; Ray, Patricio E.; Gordeuk, Victor R.; Nekhai, Sergei

    2007-10-25

    HIV-1 replication is induced by an excess of iron and iron chelation by desferrioxamine (DFO) inhibits viral replication by reducing proliferation of infected cells. Treatment of cells with DFO and 2-hydroxy-1-naphthylaldehyde isonicotinoyl hydrazone (311) inhibit expression of proteins that regulate cell-cycle progression, including cycle-dependent kinase 2 (CDK2). Our recent studies showed that CDK2 participates in HIV-1 transcription and viral replication suggesting that inhibition of CDK2 by iron chelators might also affect HIV-1 transcription. Here we evaluated the effect of a clinically approved orally effective iron chelator, 4-[3,5-bis-(hydroxyphenyl)-1,2,4-triazol-1-yl]-benzoic acid (ICL670) and 311 on HIV-1 transcription. Both ICL670 and 311 inhibited Tat-induced HIV-1 transcription in CEM-T cells, 293T and HeLa cells. Neither ICL670 nor 311 induced cytotoxicity at concentrations that inhibited HIV-1 transcription. The chelators decreased cellular activity of CDK2 and reduced HIV-1 Tat phosphorylation by CDK2. Neither ICL670A or 311 decreased CDK9 protein level but significantly reduced association of CDK9 with cyclin T1 and reduced phosphorylation of Ser-2 residues of RNA polymerase II C-terminal domain. In conclusion, our findings add to the evidence that iron chelators can inhibit HIV-1 transcription by deregulating CDK2 and CDK9. Further consideration should be given to the development of iron chelators for future anti-retroviral therapeutics.

  13. Extraction of metals using supercritical fluid and chelate forming ligand

    DOEpatents

    Wai, C.M.; Laintz, K.E.

    1998-03-24

    A method of extracting metalloid and metal species from a solid or liquid material by exposing the material to a supercritical fluid solvent containing a chelating agent is described. The chelating agent forms chelates that are soluble in the supercritical fluid to allow removal of the species from the material. In preferred embodiments, the extraction solvent is supercritical carbon dioxide and the chelating agent is a fluorinated {beta}-diketone. In especially preferred embodiments the extraction solvent is supercritical carbon dioxide, and the chelating agent comprises a fluorinated {beta}-diketone and a trialkyl phosphate, or a fluorinated {beta}-diketone and a trialkylphosphine oxide. Although a trialkyl phosphate can extract lanthanides and actinides from acidic solutions, a binary mixture comprising a fluorinated {beta}-diketone and a trialkyl phosphate or a trialkylphosphine oxide tends to enhance the extraction efficiencies for actinides and lanthanides. The method provides an environmentally benign process for removing contaminants from industrial waste without using acids or biologically harmful solvents. The method is particularly useful for extracting actinides and lanthanides from acidic solutions. The chelate and supercritical fluid can be regenerated, and the contaminant species recovered, to provide an economic, efficient process. 7 figs.

  14. Iron Chelation Adherence to Deferoxamine and Deferasirox in Thalassemia

    PubMed Central

    Trachtenberg, Felicia; Vichinsky, Elliott; Haines, Dru; Pakbaz, Zahra; Mednick, Lauren; Sobota, Amy; Kwiatkowski, Janet; Thompson, Alexis A.; Porter, John; Coates, Thomas; Giardina, Patricia J.; Olivieri, Nancy; Yamashita, Robert; Neufeld, Ellis J.

    2015-01-01

    The Thalassemia Clinical Research Network collected adherence information from 79 patients on deferoxamine and 186 on deferasirox from 2007 to 2009. Chelation adherence was defined as percent of doses administered in the last 4 weeks (patient report) out of those prescribed (chart review). Chelation history since 2002 was available for 97 patients currently on deferoxamine and 217 on deferasirox, with crude estimates of adherence from chart review. Self-reported adherence to both deferoxamine and deferasirox were quite high, with slightly higher adherence to the oral chelator (97 vs. 92%). Ninety percent of patients on deferasirox reported at least 90% adherence, compared with 75% of patients on deferoxamine. Adherence to both chelators was highest in children, followed by adolescents and older adults. Predictors of lower deferoxamine adherence were smoking in the past year, problems sticking themselves (adults only), problems wearing their pump, and fewer transfusions in the past year. Predictors of lower deferasirox adherence were bodily pain and depression. Switching chelators resulted in increased adherence, regardless of the direction of the switch, although switching from deferoxamine to deferasirox was far more common. As adherence to deferoxamine is higher than previously reported, it appears beneficial for patients to have a choice in chelators. PMID:21523808

  15. Bifunctional chelates optimized for molecular MRI.

    PubMed

    Wiener, Erik C; Abadjian, Marie-Caline; Sengar, Raghvendra; Vander Elst, Luce; Van Niekerk, Christoffel; Grotjahn, Douglas B; Leung, Po Yee; Schulte, Christie; Moore, Curtis E; Rheingold, Arnold L

    2014-07-01

    Important requirements for exogenous dyes or contrast agents in magnetic resonance imaging (MRI) include an effective concentration of paramagnetic or superparamagnetic ions at the target to be imaged. We report the concise synthesis and characterization of several new enantiopure bifunctional derivatives of (?(1)R,?(4)R,?(7)R,?(10)R)-?(1),?(4),?(7),?(10)-tetramethyl-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTMA) (and their 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) analogues as controls) that can be covalently attached to a contrast agent delivery system using either click or peptide coupling chemistry. Gd complexes of these derivatives can be attached to delivery systems while maintaining optimal water residence time for increased molecular imaging sensitivity. Long chain biotin (LC-biotin) derivatives of the Eu(III) and Gd(III) chelates associated with avidin are used to demonstrate higher efficiencies. Variable-temperature relaxometry, (17)O NMR, and nuclear magnetic resonance dispersion (NMRD) spectroscopy used on the complexes and biotin-avidin adducts measure the influence of water residence time and rotational correlation time on constrained and unconstrained systems. The Gd(III)-DOTMA derivative has a shorter water residence time than the Gd(III)-DOTA derivative. Compared to the constrained Gd(III)-DOTA derivatives, the rotationally constrained Gd(III)-DOTMA derivative has ?40% higher relaxivity at 37 C, which could increase its sensitivity as an MRI agent as well as reduce the dose of the targeting agent. PMID:24933389

  16. Bifunctional Chelates Optimized for Molecular MRI

    PubMed Central

    2015-01-01

    Important requirements for exogenous dyes or contrast agents in magnetic resonance imaging (MRI) include an effective concentration of paramagnetic or superparamagnetic ions at the target to be imaged. We report the concise synthesis and characterization of several new enantiopure bifunctional derivatives of (α1R,α4R,α7R,α10R)-α1,α4,α7,α10-tetramethyl-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTMA) (and their 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) analogues as controls) that can be covalently attached to a contrast agent delivery system using either click or peptide coupling chemistry. Gd complexes of these derivatives can be attached to delivery systems while maintaining optimal water residence time for increased molecular imaging sensitivity. Long chain biotin (LC-biotin) derivatives of the Eu(III) and Gd(III) chelates associated with avidin are used to demonstrate higher efficiencies. Variable-temperature relaxometry, 17O NMR, and nuclear magnetic resonance dispersion (NMRD) spectroscopy used on the complexes and biotin–avidin adducts measure the influence of water residence time and rotational correlation time on constrained and unconstrained systems. The Gd(III)-DOTMA derivative has a shorter water residence time than the Gd(III)-DOTA derivative. Compared to the constrained Gd(III)-DOTA derivatives, the rotationally constrained Gd(III)-DOTMA derivative has ∼40% higher relaxivity at 37 °C, which could increase its sensitivity as an MRI agent as well as reduce the dose of the targeting agent. PMID:24933389

  17. The magnesium chelation step in chlorophyll biosynthesis

    SciTech Connect

    Weinstein, J.

    1990-11-01

    In photosynthetic organisms, the biogenesis of energy transducing membranes requires the coordinate synthesis of prosthetic groups, proteins, and various lipids. Two of the major prosthetic groups, chlorophyll and heme, share a common biosynthetic pathway that diverges at the point of metal insertion into protoporphyrin IX (Proto). Insertion of iron leads to the formation of hemes, while insertion of magnesium is the first step unique to chlorophyll formation. This project is directed toward identifying the enzyme(s) responsible for magnesium chelation and elucidating the mechanism which regulates the flux of precursors through the branch point enzymes in isolated chloroplasts. Using intact chloroplasts from greening cucumber cotyledons, we have confirmed the ATP requirement for Mg-Proto formation. Use of non-hydrolyzable ATP analogs, uncouplers and ionophores has led to the conclusions that ATP hydrolysis is necessary, but that this hydrolysis is not linked to the requirement for membrane intactness by transmembrane ion gradients or electrical potentials. The enzyme(s) are flexible with respect to the porphyrin substrate specificity, accepting porphyrins with -vinyl, -ethyl, or -H substituents at the 2 and 4 positions. The activity increases approximately four-fold during greening. Possible physiological feedback inhibitors such as heme, protochlorophyllide, and chlorophyllide had no specific effect on the activity. The activity has now been assayed in barely, corn and peas, with the system from peas almost ten-fold more active than the cucumber system. Work is continuing in pea chloroplasts with the development of a continuous assay and investigation of the feasibility of characterizing an active, organelle-free preparation. 6 figs.

  18. Method for preparing radionuclide-labeled chelating agent-ligand complexes

    DOEpatents

    Meares, Claude F.; Li, Min; DeNardo, Sally J.

    1999-01-01

    Radionuclide-labeled chelating agent-ligand complexes that are useful in medical diagnosis or therapy are prepared by reacting a radionuclide, such as .sup.90 Y or .sup.111 In, with a polyfunctional chelating agent to form a radionuclide chelate that is electrically neutral; purifying the chelate by anion exchange chromatography; and reacting the purified chelate with a targeting molecule, such as a monoclonal antibody, to form the complex.

  19. Oxidative Transformations of Ferrous Iron-Bearing Smecitites: Routes to Martian Nontronites

    NASA Astrophysics Data System (ADS)

    Beehr, A. R.; Catalano, J. G.

    2011-12-01

    Data collected by the OMEGA spectrometer and the CRISM instrument indicate the presence of iron-bearing phyllosilicates on Mars' surface. Identified species include chlorite, saponite (Mg-rich smectite), and nontronite (Fe(III)-bearing smectite). The observed phyllosilicates occur in units that were deposited during the Noachian, which is thought to have had chemically reducing and alkaline conditions. Phyllosilicates are expected aqueous weathering products of basaltic minerals; the aqueous activity may have occurred episodically and hydrothermally, or as prolonged, low temperature alteration. Aqueous alkaline and reducing conditions favor the initial formation of ferrous iron-bearing phyllosilicates; subsequent surface alteration events are required to have oxidized these units into ferric smectites. Understanding the formation and oxidation of ferrous phyllosilicates can offer insight into the early Martian environment by allowing us to determine by what mechanism the oxidation occurred. We have investigated chemical and structural changes that occur upon oxidation of a synthetic ferrous saponite to determine the conditions under which such a process can produce nontronite or other ferric smectites. Both H2O2 and NO3- were used as oxidants. Hydrogen peroxide is likely the dominant oxidant currently present on Mars and nitrate is a plausible oxidant produced through photochemical processes. Deposition of photochemical nitrate is observed in the Antarctic dry valleys where it co-occurs with perchlorate, which was recently identified in Martian soil by the Phoenix lander. The initial ferrous saponite contains Fe(II) in the octahedral sheet. X-ray absorption spectroscopy (XAS) indicates that in the presence of a 1m nitrate solution under hydrothermally conditions the ferrous saponite undergoes oxidation to an Fe(III)-bearing phyllosilicate. Similar oxidation is not observed at 22C, but this appears to be a kinetic phenomenon as oxidation is thermodynamically favorable. In contrast, exposure to hydrogen peroxide causes significant oxidation regardless of temperature. However, oxidation at 22C produces a poorly crystalline material lacking substantial structural Fe. Recrystallization upon aging under mild hydrothermal conditions (150C) produces an Fe(III)-bearing phyllosilicate. X-ray diffraction indicates that this oxidized phyllosilicate is a 2:1 clay with lattice parameters similar to nontronite. XAS demonstrates that this oxidized clay contains Fe in similar local coordiation environments as two nontronite standards, NAu-2 and SWa-1. In both systems the need for hydrothermal aging to produce a nontronite-like clay likely reflects the slow rate of crystallization of smectites at room temperature on laboratory timescales rather than changes in their favorabtility of formation. Oxidation of ferrous smectites formed through weathering of basalt under reducing conditions is thus a viable formation pathway for the observed Martian nontronites.

  20. Affinity purification of copper chelating peptides from chickpea protein hydrolysates.

    PubMed

    Megías, Cristina; Pedroche, Justo; Yust, Maria M; Girón-Calle, Julio; Alaiz, Manuel; Millan, Francisco; Vioque, Javier

    2007-05-16

    Chickpea protein hydrolysates obtained with alcalase and flavourzyme were used for purification of copper chelating peptides by affinity chromatography using copper immobilized on solid supports. The chelating activity of purified peptides was indirectly measured by the inhibition of beta-carotene oxidation in the presence of copper. Two protein hydrolysates, obtained after 10 and 100 min of hydrolysis, were the most inhibitory of beta-carotene oxidation. Purified copper chelating peptides from these protein hydrolysates contained 19.7 and 35.1% histidine, respectively, in comparison to 2.7 and 2.6% in the protein hydrolysates. Chelating peptides from hydrolysate obtained after 10 min of hydrolysis were the most antioxidative being 8.3 times more antioxidative than the hydrolysate, while chelating peptides purified from protein hydrolysate obtained after 100 min were 3.1 times more antioxidative than its hydrolysate. However, the histidine content was higher in peptides derived from the 100 min hydrolysate (19.7 against 35.1% in 10 min hydrolysate), indicating that this amino acid is not the only factor involved in the antioxidative activity, and other factors such as peptide size or amino acid sequence are also determinant. This manuscript shows that affinity chromatography is a useful procedure for purification of copper chelating peptides. This method can be extended to other metals of interest in nutrition, such as calcium, iron, or zinc. Purified chelating peptides, in addition to their antioxidative properties, may also be useful in food mineral fortification for increasing the bioavailability of these metals. PMID:17428066

  1. Amelioration of iron overload-induced liver toxicity by a potent antioxidant and iron chelator, Emblica officinalis Gaertn.

    PubMed

    Sarkar, Rhitajit; Hazra, Bibhabasu; Mandal, Nripendranath

    2015-07-01

    In liver, the major site of iron storage, iron overload is associated with oxidative damage of protein, lipid, and DNA and causes protein oxidation, lipid peroxidation, and rupture of hepatocytes, leading to cell death. Serum ferritin and liver iron content are the main forecasters of moderate to severe iron overload in the liver. The sequels of excess iron deposition in the liver are fibrosis and enhanced levels of serum enzymes and bilirubin markers. Emblica officinalis (EO) fruit extract was found efficient in lessening intraperitoneally injected iron dextran-induced liver toxicity in Swiss albino mice. Mice administered with different doses of 70% methanol extract of EO (50, 100, and 200mgkg(-1) body weight) showed significant decrease in liver iron, serum ferritin, and serum enzyme levels, along with the decrease in lipid peroxidation, protein oxidation, and collagen content. The activity was further supported by its considerable iron chelation with half-maximal inhibitory concentration of 70.242.74?gml(-1) and the protection on ferrous ion-mediated DNA breakdown with 50% protection ([P]50) of 1.040.01?gml(-1). Simultaneously, the extract effectively induced the antioxidant enzyme levels and also exhibited the potential activity of reductive release of ferritin iron. These findings suggest that the EO extract may be used as a potent drug for the treatment of pathological sequences arisen in the iron overload-induced liver damage. PMID:23524878

  2. Expression profiling of the Arabidopsis ferric chelate reductase (FRO) gene family reveals differential regulation by iron and copper.

    PubMed

    Mukherjee, Indrani; Campbell, Nathan H; Ash, Joshua S; Connolly, Erin L

    2006-05-01

    The Arabidopsis FRO2 gene encodes the iron deficiency-inducible ferric chelate reductase responsible for reduction of iron at the root surface; subsequent transport of iron across the plasma membrane is carried out by a ferrous iron transporter (IRT1). Genome annotation has identified seven additional FRO family members in the Arabidopsis genome. We used real-time RT-PCR to examine the expression of each FRO gene in different tissues and in response to iron and copper limitation. FRO2 and FRO5 are primarily expressed in roots while FRO8 is primarily expressed in shoots. FRO6 and FRO7 show high expression in all the green parts of the plant. FRO3 is expressed at high levels in roots and shoots, and expression of FRO3 is elevated in roots and shoots of iron-deficient plants. Interestingly, when plants are Cu-limited, the expression of FRO6 in shoot tissues is reduced. Expression of FRO3 is induced in roots and shoots by Cu-limitation. While it is known that FRO2 is expressed at high levels in the outer layers of iron-deficient roots, histochemical staining of FRO3-GUS plants revealed that FRO3 is predominantly expressed in the vascular cylinder of roots. Together our results suggest that FRO family members function in metal ion homeostasis in a variety of locations in the plant. PMID:16362328

  3. Optimization of ferrous burden high temperature properties to meet blast furnace requirements in British Steel

    SciTech Connect

    Bergstrand, R.

    1996-12-31

    The high temperature properties of ferrous burden materials have long been an important consideration in the operation of British Steel blast furnaces. Previous research presented at this conference has shown that the behavior of materials in the lower stack and bosh can have a significant effect on furnace permeability and stability of operation. However, with increasing levels of hydrocarbon injection via the tuyeres, the reduction conditions inside British Steel blast furnaces have significantly altered over recent years. This paper focuses on the further work that has been undertaken to study the effect on ferrous burden high temperatures properties of the widely differing reduction regimes which can be experienced in today`s blast furnaces. The implications of the findings, and how they have been used in optimizing blast furnace operation and burden quality, are discussed.

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

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

    NASA Mars Exploration Rover (MER) Spirit explored Gusev Crater to look for signs of ancient aqueous activity, assess past environmental conditions and suitability for life. Spirit excavated light-toned, S-rich soils at several locations. These are likely of hydrothermal, possibly fumarolic origin. At a location dubbed Paso Robles the light-toned soil was also rich in P - a signature from surrounding rock. While S is mainly bound in ferric hydrated sulfates [1], the mineralogy of P is ill-constrained [2]. P is a key element for life and its mineralogy constrains its availability. Ferrous phases observed in Paso Robles Mössbauer spectra may represent olivine and pyroxene from surrounding basaltic soil [1] or ferrous phosphate minerals [3]. Phosphate is well-known to complex and stabilize Fe 2+ against oxidation to Fe 3+ . Schröder et al. [3] proposed a formation pathway of ferrous phosphate/ferric sulfate associations: sulfuric acid reacts with basalt containing apatite, forming CaSO4 and phosphoric acid. The phosphoric and/or excess sulfuric acid reacts with olivine, forming Fe2+-phosphate and sulfate. The phosphate is less soluble and precipitates. Ferrous sulfate remains in solution and is oxidized as pH increases. To verify this pathway, we dissolved Fe2+-chloride and Na-phosphate salts in sulfuric acid inside an anoxic glovebox. The solution was titrated to pH 6 by adding NaOH when a first precipitate formed, which was ferrous phosphate according to Mössbauer spectroscopy (MB). At that point the solution was removed from the glovebox and allowed to evaporate in the presence of atmospheric oxygen, leading to the oxidation of Fe2+. The evaporation rate was controlled by keeping the suspensions at different temperatures; pH was monitored during the evaporation process. The final precipitates were analyzed by MB and X-Ray Fluorescence (XRF), comparable to MER MB and Alpha Particle X-ray Spectrometer instrument datasets, and complementary techniques such as X-ray diffraction. Fourier Transform Infrared spectroscopy measurements to compare to MER miniature thermal emission spectrometer data are planned. We observed differences depending on the heat source during evaporation. The closest match to Martian data on the basis of Mössbauer spectra was achieved with a suspension evaporated at 80°C on a hot plate, i.e. heated from below with a temperature gradient in the bottle. The Fe2+/FeT ratio matched, and ferrous phases were all phosphate. When heated in a water bath, i.e. without a temperature gradient in the bottle, Fe2+/FeT ratios increased and ferrous sulfates precipitated also. These results indicate that the Martian light-toned S-rich deposits formed by evaporation on the surface where temperature gradients would be expected rather than underground. They confirm that ferrous phosphate/ferric sulfate associations are possible on Mars and could be preserved in the oxygen-free Martian atmosphere. References: [1] Morris et al., J.Geophys. Res. 111 (2006) E02S13; [2] Ming et al., J. Geophys. Res. 111 (2006) E02S12; [3] Schröder et al., GSA Annual Meeting 2008, Paper No. 171-3.

  5. Purification of electroplating wastewaters utilizing waste by-product ferrous sulfate and wood fly ash.

    PubMed

    Orescanin, Visnja; Mikelic, Luka; Lulic, Stipe; Nad, Karlo; Mikulic, Nenad; Rubcic, Mirta; Pavlovic, Gordana

    2004-01-01

    A new procedure for electroplating wastewater treatment using waste by-product (ferrous-sulfate) and waste (wood fly ash) is presented. Ferrous-sulfate was employed for Cr(VI) reduction whereas neutralization and heavy metal removal from electroplating wastewaters was performed using wood fly ash. Heavy metal removal efficiency varied from 97.5% for Cu to 99.973% for Zn. Satisfying results can be achieved already at the pH 8. The method is suitable for the purposes of wastewater treatment and disposal in compliance with environmental laws. Furthermore, it is technically simple, cost-efficient and requires less space compared to the classical methodology. According to the composition of its water extractable fraction remaining waste ash could be safely deposited on domestic waste repositories. PMID:15478934

  6. A modified ferrous oxidation-xylenol orange assay for lipoxygenase activity in rice grains.

    PubMed

    Timabud, Tarinee; Sanitchon, Jirawat; Pongdontri, Paweena

    2013-12-01

    Ferrous oxidation-xylenol orange assay reagent was reformulated by using spectral analysis of ferric-xylenol orange complex to detect low concentrations of lipoxygenase rice grain products. Reducing the levels of ferrous sulphate and xylenol orange in the FOX reagent enabled the detection of low concentrations of hydroperoxy fatty acid derived from lipoxygenase activity in the range of 0.1-1.5 μM. Protein, substrate and time courses of the modified FOX assay were studied to determine lipoxygenase activity in rice grain. The assay was also applicable as a high throughput technique for comparisons of lipoxygenase activity from various rice varieties. This has important implications for rapid screening for low-lipoxygenase containing rice cultivars in rice breeding program and grain quality during storage. PMID:23870974

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

    NASA Astrophysics Data System (ADS)

    Dube, R. K.

    2008-05-01

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

  8. Laser beam welding non-ferrous metals. (Latest citations from METADEX). Published Search

    SciTech Connect

    Not Available

    1994-09-01

    The bibliography contains citations concerning techniques and the evaluation of laser beam welding of non-ferrous metals. Welding parameters, such as incident laser power and welding speed, are reviewed in relation to their characterization of weld microstructure. Weld examination techniques are cited, including macrophotography, light and electron microscopy, and microhardness profiling. (Contains a minimum of 170 citations and includes a subject term index and title list.)

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

    NASA Technical Reports Server (NTRS)

    Nelson, E. E.

    1971-01-01

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

  10. Effect of ferrous sulfate and multivitamins with zinc on absorption of ciprofloxacin in normal volunteers.

    PubMed Central

    Polk, R E; Healy, D P; Sahai, J; Drwal, L; Racht, E

    1989-01-01

    Cations such as magnesium and aluminum significantly impair the absorption of ciprofloxacin. Twelve healthy adult male volunteers participated in this four-way crossover study to investigate the effects of ferrous sulfate and multivitamins with zinc on the absorption of ciprofloxacin. Doses of ciprofloxacin (500 mg) were given 7 days apart and after an overnight fast. Dose 1 was administered alone (regimen A). The subjects then received either a ferrous sulfate tablet (325 mg three times a day; regimen B) or a once-daily multivitamin with zinc (regimen C) for 7 days; dose 2 of ciprofloxacin was then given with the last dose of regimen B or C. Subjects were crossed over to the alternate regimen for 7 days, and dose 3 of ciprofloxacin was again administered with the last dose of regimen B or C. After a 7-day washout, dose 4 of ciprofloxacin was given (regimen D). Ciprofloxacin concentrations were determined by high-pressure liquid chromatography. The areas under the concentration-time curve (AUCs) of ciprofloxacin for regimens A and D were not significantly different (14.5 +/- 2.3 versus 15.7 +/- 2.8 micrograms.h/ml, mean +/- standard deviation). The AUCs for regimen B (5.4 +/- 1.7 micrograms.h/ml) and regimen C (11.3 +/- 2.4 micrograms.h/ml) were significantly different from the AUCs for regimens A and D. Peak concentrations of ciprofloxacin with regimen B were below the MIC for 90% of strains of many organisms normally considered susceptible. Ferrous sulfate and multivitamins with zinc significantly impaired the absorption of ciprofloxacin. The effect of ferrous sulfate is likely to be clinically significant; the responsible component of multivitamins with zinc requires additional study. PMID:2610494

  11. Ab Initio Coordination Chemistry for Nickel Chelation Motifs

    PubMed Central

    Jesu Jaya Sudan, R.; Lesitha Jeeva Kumari, J.; Sudandiradoss, C.

    2015-01-01

    Chelation therapy is one of the most appreciated methods in the treatment of metal induced disease predisposition. Coordination chemistry provides a way to understand metal association in biological structures. In this work we have implemented coordination chemistry to study nickel coordination due to its high impact in industrial usage and thereby health consequences. This paper reports the analysis of nickel coordination from a large dataset of nickel bound structures and sequences. Coordination patterns predicted from the structures are reported in terms of donors, chelate length, coordination number, chelate geometry, structural fold and architecture. The analysis revealed histidine as the most favored residue in nickel coordination. The most common chelates identified were histidine based namely HHH, HDH, HEH and HH spaced at specific intervals. Though a maximum coordination number of 8 was observed, the presence of a single protein donor was noted to be mandatory in nickel coordination. The coordination pattern did not reveal any specific fold, nevertheless we report preferable residue spacing for specific structural architecture. In contrast, the analysis of nickel binding proteins from bacterial and archeal species revealed no common coordination patterns. Nickel binding sequence motifs were noted to be organism specific and protein class specific. As a result we identified about 13 signatures derived from 13 classes of nickel binding proteins. The specifications on nickel coordination presented in this paper will prove beneficial for developing better chelation strategies. PMID:25985439

  12. Chelation in metal intoxication--Principles and paradigms.

    PubMed

    Aaseth, Jan; Skaug, Marit Aralt; Cao, Yang; Andersen, Ole

    2015-01-01

    The present review provides an update of the general principles for the investigation and use of chelating agents in the treatment of intoxications by metals. The clinical use of the old chelators EDTA (ethylenediamine tetraacetate) and BAL (2,3-dimercaptopropanol) is now limited due to the inconvenience of parenteral administration, their own toxicity and tendency to increase the neurotoxicity of several metals. The hydrophilic dithiol chelators DMSA (meso-2,3-dimercaptosuccinic acid) and DMPS (2,3-dimercapto-propanesulphonate) are less toxic and more efficient than BAL in the clinical treatment of heavy metal poisoning, and available as capsules for oral use. In copper overload, DMSA appears to be a potent antidote, although d-penicillamine is still widely used. In the chelation of iron, the thiols are inefficient, since iron has higher affinity for ligands with nitrogen and oxygen, but the new oral iron antidotes deferiprone and desferasirox have entered into the clinical arena. Comparisons of these agents and deferoxamine infusions are in progress. General principles for research and development of new chelators are briefly outlined in this review. PMID:25457281

  13. Chemical decontamination of process equipment using recyclable chelating agents

    SciTech Connect

    Palmer, P.A.

    1994-10-01

    The Babcock and Wilcox Company is performing research and development in the application of chelating chemicals to dissolve uranium compounds and other actinide species from the surfaces of DOE process equipment. A chelating system specific for the removal of uranium and other actinides will be applied to the component selected for full-scale demonstration of the process. After application of the chelating solvent for an appropriate time period, the spent solvent will be removed to a waste processing facility, and the dissolved radioactive contaminants will be precipitated out of the solution. The regenerated chelating solvent will then be available for reuse in the cleaning system, thereby minimizing the amount of secondary waste generated by the process. Phase 1 activity has begun with bench-scale tests in the laboratory, to screen and optimize candidate solvent systems, and will proceed to development of a chemical cleaning process that will be tested in a pilot facility on an actual piece of contaminated equipment. The potential for application of the chelating agent as a foam rather than a liquid will also be investigated. The advantage of foaming application is a reduction of solvent volume requiring eventual treatment. The second phase of this program will be a full-scale demonstration of the developed technology on contaminated process equipment at a DOE site.

  14. 3-hydroxy-2(1H)-pyridinone chelating agents

    DOEpatents

    Raymond, Kenneth N. (Berkeley, CA); Xu, Jide (Berkeley, CA)

    1997-01-01

    Disclosed is a series of improved metal chelating agents, which are highly effective upon both injection and oral administration; several of the most effective are of low toxicity. These chelating agents incorporate within their structure 1-hydroxy-2-pyridinone (1,2-HOPO) and 3-hydroxy-2-pyridinone (3,2-HOPO) moieties with a substituted carbamoyl group ortho to the hydroxy or oxo groups of the hydroxypyridinone ring. The electron-withdrawing carbamoyl group increases the acidity of the hydroxypyridinones. In the metal complexes of said chelating agents, the amide protons form very strong hydrogen bonds with its adjacent HOPO oxygen donor, making these complexes very stable at physiological conditions. The terminal N-substituents provides a certain degree of lipophilicity to said 3,2-HOPO, increasing oral activity. Also disclosed is a method of making the chelating agents and a method of producing a known compound, 3-hydroxy-1-alkyl-2(1H)pyridinone, used as a precursor to the chelating agent, safely and in large quantities.

  15. Oxidation-Induced Degradable Nanogels for Iron Chelation

    PubMed Central

    Liu, Zhi; Wang, Yan; Purro, Max; Xiong, May P.

    2016-01-01

    Iron overload can increase cellular oxidative stress levels due to formation of reactive oxygen species (ROS); untreated, it can be extremely destructive to organs and fatal to patients. Since elevated oxidative stress levels are inherent to the condition in such patients, oxidation-induced degradable nanogels for iron chelation were rationally designed by simultaneously polymerizing oxidation-sensitive host-guest crosslinkers between β-cyclodextrin (β-CD) and ferrocene (Fc) and iron chelating moieties composed of deferoxamine (DFO) into the final gel scaffold in reverse emulsion reaction chambers. UV-Vis absorption and atomic absorption spectroscopy (AAS) was used to verify iron chelating capability of nanogels. These materials can degrade into smaller chelating fragments at rates proportional to the level of oxidative stress present. Conjugating DFO reduces the cytotoxicity of the chelator in the macrophage cells. Importantly, the nanogel can effectively reduce cellular ferritin expression in iron overloaded cells and regulate intracellular iron levels at the same time, which is important for maintaining a homeostatic level of this critical metal in cells. PMID:26868174

  16. 3-hydroxy-2(1H)-pyridinone chelating agents

    DOEpatents

    Raymond, K.N.; Xu, J.

    1997-04-29

    Disclosed is a series of improved metal chelating agents, which are highly effective upon both injection and oral administration; several of the most effective are of low toxicity. These chelating agents incorporate within their structure 1-hydroxy-2-pyridinone (1,2-HOPO) and 3-hydroxy-2-pyridinone (3,2-HOPO) moieties with a substituted carbamoyl group ortho to the hydroxy or oxo groups of the hydroxypyridinone ring. The electron-withdrawing carbamoyl group increases the acidity of the hydroxypyridinones. In the metal complexes of the chelating agents, the amide protons form very strong hydrogen bonds with its adjacent HOPO oxygen donor, making these complexes very stable at physiological conditions. The terminal N-substituents provides a certain degree of lipophilicity to the 3,2-HOPO, increasing oral activity. Also disclosed is a method of making the chelating agents and a method of producing a known compound, 3-hydroxy-1-alkyl-2(1H)pyridinone, used as a precursor to the chelating agent, safely and in large quantities. 2 figs.

  17. Analysis of metal chelates by electrospray ionization mass spectrometry

    SciTech Connect

    Wahl, K.L.; Stromatt, R.W.; Blanchard, D.L.

    1995-12-31

    Solubilized metal ions pose a potential environmental threat for many waste-disposal sites. Understanding the behavior of metal ions in complex organic matrices and the possible metal-chelate complexes that could form may aid in developing remediation techniques. For example, waste tanks on the Hanford Site are known to contain large amounts of chelators such as ethylenediaminetetraacetic acid (EDTA). These chelators may be responsible for difficulties in removing some of the radioactive metals, such as {sup 90}Sr. One possible method for examining these metal-chelate complexes is electrospray ionization mass spectrometry (ESI-MS). The goal of this project is to examine the behavior of strontium (Sr) in complex mixtures containing a variety of inorganic and organic components that simulate tank waste constituents. Preliminary results presented suggest that ESI-MS can be used to study the behavior of chelators, such as EDTA, N-(2-hydroxyethyl)ethylenediaminetriacetic acid (HEDTA), and nitrilotriacetic acid (NTA), in the presence of metals such as iron (Fe) and Sr.

  18. Oxidation-Induced Degradable Nanogels for Iron Chelation.

    PubMed

    Liu, Zhi; Wang, Yan; Purro, Max; Xiong, May P

    2016-01-01

    Iron overload can increase cellular oxidative stress levels due to formation of reactive oxygen species (ROS); untreated, it can be extremely destructive to organs and fatal to patients. Since elevated oxidative stress levels are inherent to the condition in such patients, oxidation-induced degradable nanogels for iron chelation were rationally designed by simultaneously polymerizing oxidation-sensitive host-guest crosslinkers between ?-cyclodextrin (?-CD) and ferrocene (Fc) and iron chelating moieties composed of deferoxamine (DFO) into the final gel scaffold in reverse emulsion reaction chambers. UV-Vis absorption and atomic absorption spectroscopy (AAS) was used to verify iron chelating capability of nanogels. These materials can degrade into smaller chelating fragments at rates proportional to the level of oxidative stress present. Conjugating DFO reduces the cytotoxicity of the chelator in the macrophage cells. Importantly, the nanogel can effectively reduce cellular ferritin expression in iron overloaded cells and regulate intracellular iron levels at the same time, which is important for maintaining a homeostatic level of this critical metal in cells. PMID:26868174

  19. The role of chelation in the treatment of other metal poisonings.

    TOXLINE Toxicology Bibliographic Information

    Smith SW

    2013-12-01

    These proceedings will review the role of chelation in five metals-aluminum, cadmium, chromium, cobalt, and uranium-in order to illustrate various chelation concepts. The process of "chelation" can often be oversimplified, leading to incorrect assumptions and risking patient harm. For chelation to be effective, two critical assumptions must be fulfilled: the presumed "metal toxicity" must correlate with a given body or a particular compartment burden, and reducing this compartmental or the body burden (through chelation) attenuates toxicity. Fulfilling these assumptions requires an established dose-response relationship, a validated, reproducible means of toxicity assessment (clinical, biochemical, or radiographical), and an appropriate assessment mechanisms of body or compartment burden. While a metal might "technically" be capable of chelation (and readily demonstrable in urine or feces), this is an insufficient endpoint. Clinical relevance must be affirmed. Deferoxamine is an accepted chelator for appropriately documented aluminum toxicity. There is a very minimal treatment window in order to address chelation in cadmium toxicity. In acute toxicity, while no definitive chelation benefit is described, succimer (DMSA), diethylenetriaminepentaacetate (DTPA), and potentially ethylenediaminetetraacetic acid (EDTA) have been considered. In chronic toxicity, chelation is unsupported. There is little evidence to suggest that currently available chromium chelators are efficacious. Similarly, scant human evidence exists with which to provide recommendation for cobalt chelation. DTPA has been recommended for cobalt radionuclide chelation, although DMSA, EDTA, and N-acetylcysteine have also been suggested. DTPA is unsupported for uranium chelation. Sodium bicarbonate is currently recommended, although animal evidence is conflicting.

  20. Stable intermediate-spin ferrous iron in lower-mantle perovskite

    SciTech Connect

    McCammon, C.; Kantor, I.; Narygina, O.; Rouquette, J.; Ponkratz, U.; Sergueev, I.; Mezouar, M.; Prakapenka, V.; Dubrovinsky, L.

    2008-11-10

    The lower mantle is dominated by a magnesium- and iron-bearing mineral with the perovskite structure. Iron has the ability to adopt different electronic configurations, and transitions in its spin state in the lower mantle can significantly influence mantle properties and dynamics. However, previous studies aimed at understanding these transitions have provided conflicting results. Here we report the results of high-pressure (up to 110 GPa) and high-temperature (up to 1,000 K) experiments aimed at understanding spin transitions of iron in perovskite at lower-mantle conditions. Our Moessbauer and nuclear forward scattering data for two lower-mantle perovskite compositions demonstrate that the transition of ferrous iron from the high-spin to the intermediate-spin state occurs at approximately 30 GPa, and that high temperatures favour the stability of the intermediate-spin state. We therefore infer that ferrous iron adopts the intermediate-spin state throughout the bulk of the lower mantle. Our X-ray data show significant anisotropic compression of lower-mantle perovskite containing intermediate-spin ferrous iron, which correlates strongly with the spin transition. We predict spin-state heterogeneities in the uppermost part of the lower mantle associated with sinking slabs and regions of upwelling. These may affect local properties, including thermal and electrical conductivity, deformation (viscosity) and chemical behaviour, and thereby affect mantle dynamics.

  1. Isolation and characterization of an acidophilic, heterotrophic bacterium capable of oxidizing ferrous iron.

    PubMed Central

    Johnson, D B; Ghauri, M A; Said, M F

    1992-01-01

    A heterotrophic bacterium, isolated from an acidic stream in a disused pyrite mine which contained copious growths of "acid streamers," displayed characteristics which differentiated it from previously described mesophilic acidophiles. The isolate was obligately acidophilic, with a pH range of 2.0 to 4.4 and an optimum pH of 3.0. The bacterium was unable to fix carbon dioxide but oxidized ferrous iron, although at a slower rate than either Thiobacillus ferrooxidans or Leptospirillum ferrooxidans. Elemental sulfur and manganese(II) were not oxidized. In liquid media, the isolate produced macroscopic streamerlike growths. Microscopic examination revealed that the bacterium formed long (greater than 100 microns) filaments which tended to disintegrate during later growth stages, producing single, motile cells and small filaments. The isolate did not appear to utilize the energy from ferrous iron oxidation. Both iron (ferrous or ferric) and an organic substrate were necessary to promote growth. The isolate displayed a lower tolerance to heavy metals than other iron-oxidizing acidophiles, and growth was inhibited by exposure to light. There was evidence of extracellular sheath production by the isolate. In this and some other respects, the isolate resembles members of the Sphaerotilus-Leptothrix group of filamentous bacteria. The guanine-plus-cytosine content of the isolate was 62 mol%, which is less than that recorded for Sphaerotilus-Leptothrix spp. and greater than those of L. ferrooxidans and most T. ferrooxidans isolates. Images PMID:1622207

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

    NASA Astrophysics Data System (ADS)

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

    1993-04-01

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

  3. Folding process of silk fibroin induced by ferric and ferrous ions

    NASA Astrophysics Data System (ADS)

    Ji, Dan; Deng, Yi-Bin; Zhou, Ping

    2009-12-01

    Bombyx mori silk fiber has useful mechanical properties largely due to a high content of ordered ?-sheet crystallites separated by non-crystalline spacers. Metallic ions present in the silk dope in nature could affect the ?-sheet content. In this work, we used solid-state 13C NMR, EPR and Raman spectroscopy to investigate how the ferric/ferrous ions affect the folding process of the silk fibroin. NMR and Raman results indicate that ferric and ferrous ions have different effects on the secondary structure of silk fibroin. Ferric ions can induce a conformation change from helix to ?-sheet form in silk fibroin when their concentration exceeds a critical value, while ferrous ions cannot. EPR results indicate that the ferric ions bound with silk fibroin have a high-spin state ( S = 5/2) with g-value of g1 = 1.950, g2 = 1.990 and g3 = 1.995, zero-field splitting interaction D of 1.2-2 cm -1, and symmetric character of E/ D = 1/3, resulting in an effective g-value of g' = 4.25. The hydrophilic spacer GTGSSGFGPYVAN(H)GGYSGYEYAWSSESDFGT in the heavy chain of silk fibroin is likely to be involved in the binding of ferric ions, and His, Asn and Tyr residues are considered as the potential binding sites.

  4. LITERATURE REVIEW: REDUCTION OF NP(V) TO NP (IV)-ALTERNATIVES TO FERROUS SULFAMATE

    SciTech Connect

    Kessinger, G.; Kyser, E.; Almond, P.

    2009-09-28

    The baseline approach to control of Np oxidation in UREX and PUREX separation processes is the reduction of Np(V) and Np(VI) to Np(IV) using ferrous sulfamate. Use of this reagent results in increased sulfur and iron concentrations in the liquid waste streams from the process. Presence of these two elements, especially sulfur, increases the complexity of the development of wasteforms for immobilizing these effluents. Investigations are underway to identify reductants that eliminate sulfur and iron from the Np reduction process. While there are a variety of chemical reductants that will reduce Np to Np(IV) in nitric acid media, the reaction rates for most are so slow that the reductants are not be feasible for use in an operating plant process. In an attempt to identify additional alternatives to ferrous sulfamate, a literature search and review was performed. Based on the results of the literature review, it is concluded that photochemical and catalytic processes should also be investigated to test the utility of these two approaches. The catalytic process could be investigated for use in conjunction with chemical oxidants to speed the reaction rates for reductants that react slowly, but would otherwise be appropriate replacements for ferrous sulfamate. The photochemical approach, which has received little attention during the past few decades, also shows promise, especially the photocatalytic approach that includes a catalyst, such as Pt supported on SiC, which can be used in tandem with an oxidant, for Np reduction.

  5. Molecular nanotechnologies of gelatin-immobilization using macrocyclic metal chelates

    PubMed Central

    Mikhailov, Oleg V.

    2014-01-01

    This article is a review of recent developments in the self-assembled nanostructures based on chelate coordination compounds. Molecular nanotechnologies of self-assembly of 3d-element aza- and thiazametalmacrocyclic complexes that happen in nanoreactors on the basis of metal hexacyanoferrate(II) gelatin-immobilized matrix under their contact with water solutions containing various (N,O,S)-donor atomic ligands and organic compounds having one or two carbonyl groups have been considered in this review. It has been noted that the assortment of macrocyclic metal chelates obtained as a result of using molecular nanotechnologies in such specific conditions considerably differs from the assortment of metal chelates formed at the conditions traditional for chemical synthesis. PMID:24516711

  6. Bifunctional chelates of Rh-105 and Au-199 as potential radiotherapeutic agents

    SciTech Connect

    Troutner, D.E.; Schlemper, E.O.

    1990-01-25

    Since last year we have: continued the synthesis of pentadentate bifunctional chelating agents based on diethylene triamine; studied the chelation Rh-105, Au-198 (as model for Au-199) and Tc-99m with these agents as well as chelation of Pd-109, Cu-67, In-111, and Co-57 with some of them; synthesized a new class of potential bifunctional chelating agents based on phenylene diamine; investigated the behavior of Au-198 as a model for Au-199; begun synthesis of bifunctional chelating agents based on terpyridly and similar ligands; and continued attempts to produce tetradentate bifunctional chelates based on diaminopropane. Each of these will be addressed in this report.

  7. Clinical monitoring and management of complications related to chelation therapy in patients with β-thalassemia.

    PubMed

    Saliba, Antoine N; El Rassi, Fuad; Taher, Ali T

    2016-02-01

    Iron chelating agents - deferoxamine (DFO), deferiprone (DFP), and deferasirox (DFX) - are used to treat chronic iron overload in patients with β-thalassemia in an attempt to reduce morbidity and mortality related to siderosis. Each of the approved iron chelating agents has its own advantages over the others and also has its own risks, whether related to over-chelation or not. In this review, we briefly discuss the methods to monitor the efficacy of iron chelation therapy (ICT) and the evidence behind the use of each iron chelating agent. We also portray the risks and complications associated with each iron chelating agent and recommend strategies to manage adverse events. PMID:26613264

  8. Combinational chelation therapy abrogates lead-induced neurodegeneration in rats

    SciTech Connect

    Pachauri, Vidhu; Saxena, Geetu; Mehta, Ashish; Mishra, Deepshikha; Flora, Swaran J.S.

    2009-10-15

    Lead, a ubiquitous and potent neurotoxicant causes oxidative stress which leads to numerous neurobehavioral and physiological alterations. The ability of lead to bind sulfhydryl groups or compete with calcium could be one of the reasons for its debilitating effects. In the present study, we addressed: i) if chelation therapy could circumvent the altered oxidative stress and prevent neuronal apoptosis in chronic lead-intoxicated rats, ii) whether chelation therapy could reverse biochemical and behavioral changes, and iii) if mono or combinational therapy with captopril (an antioxidant) and thiol chelating agents (DMSA/MiADMSA) is more effective than individual thiol chelator in lead-exposed rats. Results indicated that lead caused a significant increase in reactive oxygen species, nitric oxide, and intracellular free calcium levels along with altered behavioral abnormalities in locomotor activity, exploratory behavior, learning, and memory that were supported by changes in neurotransmitter levels. A fall in membrane potential, release of cytochrome c, and DNA damage indicated mitochondrial-dependent apoptosis. Most of these alterations showed significant recovery following combined therapy with captopril with MiADMSA and to a smaller extend with captopril + DMSA over monotherapy with these chelators. It could be concluded from our present results that co-administration of a potent antioxidant (like captopril) might be a better treatment protocol than monotherapy to counter lead-induced oxidative stress. The major highlight of the work is an interesting experimental evidence of the efficacy of combinational therapy using an antioxidant with a thiol chelator in reversing neurological dystrophy caused due to chronic lead exposure in rats.

  9. Heavy metal displacement in chelate-irrigated soil during phytoremediation

    NASA Astrophysics Data System (ADS)

    Madrid, F.; Liphadzi, M. S.; Kirkham, M. B.

    2003-03-01

    Heavy metals in wastewater sewage sludge (biosolids), applied to land, contaminate soils. Phytoremediation, the use of plants to clean up toxic heavy metals, might remove them. Chelating agents are added to soil to solubilize the metals for enhanced phytoextraction. Yet no studies follow the displacement and leaching of heavy metals in soil with and without roots following solubilization with chelates. The objective of this work was to determine the mobility of heavy metals in biosolids applied to the surface of soil columns (76 cm long; 17 cm diam.) with or without plants (barley; Hordeum vulgare L.). Three weeks after barley was planted, all columns were irrigated with the disodium salt of the chelating agent, EDTA (ethylenediamine tetraacetic acid) (0.5 g/kg soil). Drainage water, soil, and plants were analyzed for heavy metals (Cd, Cu, Fe, Mn, Ni, Pb, Zn). Total concentrations of the heavy metals in all columns at the end of the experiment generally were lower in the top 30 cm of soil with EDTA than without EDTA. The chelate increased concentrations of heavy metals in shoots. With or without plants, the EDTA mobilized Cd, Fe, Mn, Ni, Pb, and Zn, which leached to drainage water. Drainage water from columns without EDTA had concentrations of these heavy metals below detection limits. Only Cu did not leach in the presence of EDTA. Even though roots retarded the movement of Cd, Fe, Mn, Ni, Pb, and Zn through the EDTA-treated soil from 1 d (Cd) to 5 d (Fe), the drainage water from columns with EDTA had concentrations of Cd, Fe, Mn, and Pb that exceeded drinking water standards by 1.3, 500, 620, and 8.6 times, respectively. Because the chelate rendered Cd, Fe, Mn, Ni, Pb, and Zn mobile, it is suggested that the theory for leaching of soluble salts, put forward by Nielsen and associates in 1965, could be applied to control movement of the heavy metals for maximum uptake during chelate-assisted phytoremediation.

  10. Biocombinatorial Selection of Metal Ion-Chelating Peptides

    NASA Astrophysics Data System (ADS)

    Matsubara, Teruhiko; Hiura, Yuko; Kawashiro, Katsuhiro

    A phage-displayed library selection was performed to obtain metal ion-chelating peptides. A dodecamer (12-mer) random peptide library was displayed on the surface of filamentous bacterial phage and subjected to an affinity selection. Four rounds of the selection gave fourteen Zn2+-positive phage clones. Enzyme-linked immunosorbent assay showed that the selected clones specifically bound to Zn2+ and Ni2+, but not to Cu2+ and Fe3+. Deduced amino acid sequences of the clones had histidine-rich consensus motifs. These chelating peptides should be applied to designing for metal ion-trapping biomaterials.

  11. Cytotoxic effects of the lipophilic iron chelator omadine.

    PubMed

    Kontoghiorghes, G J; Piga, A; Hoffbrand, A V

    1986-08-18

    Cytotoxic effects were observed following 4 h incubation of human leukaemic cells with the iron chelator 1-hydroxypyridine-2-thione (omadine). Its cytotoxic activity was comparable to that of the cytotoxic drug doxorubicin. At the same concentration two other effective iron chelators, desferrioxamine and 1,2-dimethyl-3-hydroxypyrid-4-one, were not cytotoxic. Addition of iron augmented the effect of omadine. It is suggested that the lipophilic properties of omadine and of its iron complex cause their intracellular accumulation and potent cytotoxic activity. PMID:3460820

  12. Removal of phenol from saline water by polyamine chelating resin.

    PubMed

    Yamada, Arisa; Matsui, Akihiro; Tsuji, Hideyuki

    2013-01-01

    Removal of phenol from saline water was carried out with chelating resin. A polyamine chelating resin, Diaion CR-20, removed phenol compounds selectively from industrial wastewater containing 2% salt. From saline water containing 20 mg/L phenol, 70% of the phenol was removed. After treatment, phenol was eluted from the resin by aqueous NaOH, and the resin could also be regenerated by heating in air. Diaion CR-20 adsorbed phenol even in the presence of FeCl3, indicating that treatment with this resin of wastewater containing metal can remove phenol and metal cations in a single step. PMID:24185065

  13. Iron chelating strategies in systemic metal overload, neurodegeneration and cancer.

    PubMed

    Gumienna-Kontecka, Elzbieta; Pyrkosz-Bulska, Monika; Szebesczyk, Agnieszka; Ostrowska, Malgorzata

    2014-01-01

    Iron is a trace element required for normal performance of cellular processes. Because both the deficiency and excess of this metal are dangerous, its absorption, distribution and accumulation must be tightly regulated. Disturbances of iron homeostasis and an increase in its level may lead to overload and neurodegenerative diseases. Phlebotomy was for a long time the only way of removing excess iron. But since there are many possible disadvantages of this method, chelation therapy seems to be a logical approach to remove toxic levels of iron. In clinical use, there are three drugs: desferrioxamine, deferiprone and deferasirox. FBS0701, a novel oral iron chelator, is under clinical trials with very promising results. Developing novel iron-binding chelators is an urgent matter, not only for systemic iron overload, but also for neurodegenerative disorders, such as Parkinson's disease. Deferiprone is also used in clinical trials in Parkinson's disease. In neurodegenerative disorders the main goal is not only to remove iron from brain tissues, but also its redistribution in system. Few chelators are tested for their potential use in neurodegeneration, such as nonhalogeneted derivatives of clioquinol. Such compounds gave promising results in animal models of neurodegenerative diseases. Drugs of possible use in neurodegeneration must meet certain criteria. Their development includes the improvement in blood brain barrier permeability, low toxicity and the ability to prevent lipid peroxidation. One of the compounds satisfying these requirements is VK28. In rat models it was able to protect neurons in very low doses without significantly changing the iron level in liver or serum. Also iron chelators able to regulate activity of monoamine oxidase were tested. Polyphenols and flavonoids are able to prevent lipid peroxidation and demonstrate neuroprotective activity. While cancer does not involve true iron overload, neoplastic cells have a higher iron requirement and are especially prone to its depletion. It was shown, that desferrioxamine and deferasirox are antiproliferative agents active in several types of cancer. Very potent compounds with possible use as anticancer drugs are thiosemicarbazones. They are able to inhibit ribonucleotide reductase, an enzyme involved in DNA synthesis. Because the relationship between the development of overload / neurodegenerative disorders, or cancer, and iron are very complex, comprehension of the mechanisms involved in the regulation of iron homeostasis is a crucial factor in the development of new pharmacological strategies based on iron chelation. In view of various factors closely involved in pathogenesis of such diseases, designing multifunctional metal-chelators seems to be the most promising approach, but it requires a lot of effort. In this perspective, the review summarizes systemic iron homeostasis, and in brain and cancer cells, iron dysregulation in neurodegenerative disease and possible chelation strategies in the treatment of metal systemic overload, neurodegeneration and cancer. PMID:25005181

  14. Enumeration and Detection of Anaerobic Ferrous Iron-Oxidizing, Nitrate-Reducing Bacteria from Diverse European Sediments

    PubMed Central

    Straub, Kristina L.; Buchholz-Cleven, Berit E. E.

    1998-01-01

    Anaerobic, nitrate-dependent microbial oxidation of ferrous iron was recently recognized as a new type of metabolism. In order to study the occurrence of three novel groups of ferrous iron-oxidizing, nitrate-reducing bacteria (represented by strains BrG1, BrG2, and BrG3), 16S rRNA-targeted oligonucleotide probes were developed. In pure-culture experiments, these probes were shown to be suitable for fluorescent in situ hybridization, as well as for hybridization analysis of denaturing gradient gel electrophoresis (DGGE) patterns. However, neither enumeration by in situ hybridization nor detection by the DGGE-hybridization approach was feasible with sediment samples. Therefore, the DGGE-hybridization approach was combined with microbiological methods. Freshwater sediment samples from different European locations were used for enrichment cultures and most-probable-number (MPN) determinations. Bacteria with the ability to oxidize ferrous iron under nitrate-reducing conditions were detected in all of the sediment samples investigated. At least one of the previously described types of bacteria was detected in each enrichment culture. MPN studies showed that sediments contained from 1 105 to 5 108 ferrous iron-oxidizing, nitrate-reducing bacteria per g (dry weight) of sediment, which accounted for at most 0.8% of the nitrate-reducing bacteria growing with acetate. Type BrG1, BrG2, and BrG3 bacteria accounted for an even smaller fraction (0.2% or less) of the ferrous iron-oxidizing, nitrate-reducing community. The DGGE patterns of MPN cultures suggested that more organisms than those isolated thus far are able to oxidize ferrous iron with nitrate. A comparison showed that among the anoxygenic phototrophic bacteria, organisms that have the ability to oxidize ferrous iron also account for only a minor fraction of the population. PMID:9835573

  15. Iron chelating active packaging: Influence of competing ions and pH value on effectiveness of soluble and immobilized hydroxamate chelators.

    PubMed

    Ogiwara, Yoshiko; Roman, Maxine J; Decker, Eric A; Goddard, Julie M

    2016-04-01

    Many packaged foods utilize synthetic chelators (e.g. ethylenediaminetetraacetic acid, EDTA) to inhibit iron-promoted oxidation or microbial growth which would result in quality loss. To address consumer demands for all natural products, we have previously developed a non-migratory iron chelating active packaging material by covalent immobilization of polyhydroxamate and demonstrated its efficacy in delaying lipid oxidation. Herein, we demonstrate the ability of this hydroxamate-functionalized iron chelating active packaging to retain iron chelating capacity; even in the presence of competing ions common in food. Both immobilized and soluble hydroxamate chelators retained iron chelating capacity in the presence of calcium, magnesium, and sodium competing ions, although at pH 5.0 the presence of calcium reduced immobilized hydroxamate iron chelation. A strong correlation was found between colorimetric and mass spectral analysis of iron chelation by the chelating packaging material. Such chelating active packaging may support reducing additive use in product formulations, while retaining quality and shelf life. PMID:26593563

  16. Chelation-controlled regioselective alkylation of pyrimidine 2'-deoxynucleosides.

    PubMed

    Lucas, R; Teste, K; Zerrouki, R; Champavier, Y; Guilloton, M

    2010-01-26

    Protection-deprotection steps, which are usually needed for regioselective alkylation of pyrimidine deoxynucleosides, can be avoided by choosing the appropriate solvent. The combined effects of low dielectric constant and possible sodium chelation by pyrimidine nucleosides may account for the unexpected regioselectivity observed in THF. PMID:19932891

  17. Chelation of thallium by combining deferasirox and desferrioxamine in rats.

    PubMed

    Saljooghi, Amir Shokooh; Babaie, Maryam; Mendi, Fatemeh Delavar; Zahmati, Maliheh; Saljooghi, Zoheir Shokouh

    2016-01-01

    The hypothesis that two known chelators deferasirox (4-[3,5-bis(2-hydroxyphenyl)-1,2,4-triazol-1-yl]-benzoic acid) and desferrioxamine (DFO) might be more efficient as combined treatment than as monotherapies in removing thallium from the body was tested in a new acute rat model. 7-week-old male Wistar rats received chelators: deferasirox (orally), DFO (intraperitoneal; i.p.), or deferasirox + DFO as 75 or 150 mg/kg dose half an hour after a single i.p. administration of 8 mg thallium/kg body weight in the form of chloride. Serum thallium concentration, urinary thallium, and iron excretions were determined by graphite furnace atomic absorption spectrometry. Both chelators were effective only at the higher dose level, while DFO was more effective than deferasirox in enhancing urinary thallium excretion, deferasirox was more effective than DFO in enhancing urinary iron excretion. In the combined treatment group, deferasirox did not increase the DFO effect on thallium and DFO did not increase the effect of deferasirox on iron elimination. Our results support the usefulness of this animal model for preliminary in vivo testing of thallium chelators. Urinary values were more useful because of the high variability of serum results. PMID:24021432

  18. A versatile water-soluble chelating and radical scavenging platform.

    PubMed

    Eckshtain-Levi, Meital; Lavi, Ronit; Yufit, Dmitry S; Daniel, Bareket; Green, Omer; Fleker, Ohad; Richman, Michal; Rahimipour, Shai; Gruzman, Arie; Benisvy, Laurent

    2016-01-28

    The phenol-diamide compound, 5-(tert-butyl)-2-hydroxy-N1,N3-bis(2-hydroxyethyl)isophthalamide (), is water-soluble, non-cytotoxic, and capable of both, trapping ROS species and chelating Cu(ii) and Fe(iii) ions; these combined properties confer a protective effect against ROS induced cell death. PMID:26731129

  19. Desferrithiocin: A Search for Clinically Effective Iron Chelators

    PubMed Central

    2015-01-01

    The successful search for orally active iron chelators to treat transfusional iron-overload diseases, e.g., thalassemia, is overviewed. The critical role of iron in nature as a redox engine is first described, as well as how primitive life forms and humans manage the metal. The problems that derive when iron homeostasis in humans is disrupted and the mechanism of the ensuing damage, uncontrolled Fenton chemistry, are discussed. The solution to the problem, chelator-mediated iron removal, is clear. Design options for the assembly of ligands that sequester and decorporate iron are reviewed, along with the shortcomings of the currently available therapeutics. The rationale for choosing desferrithiocin, a natural product iron chelator (a siderophore), as a platform for structureactivity relationship studies in the search for an orally active iron chelator is thoroughly developed. The study provides an excellent example of how to systematically reengineer a pharmacophore in order to overcome toxicological problems while maintaining iron clearing efficacy and has led to three ligands being evaluated in human clinical trials. PMID:25207964

  20. Evaluation of intakes of transuranics influenced by chelation therapy

    SciTech Connect

    LaBone, T.R.

    1994-02-01

    Once an intake of transuranics occurs, there are only three therapeutic procedures available to the physician for reducing the intake and mitigating the dose: excision of material from wounds, removal of material from the lungs with lavage, and chelation therapy. The only chelation agents approved in the United States for the treatment of occupational intakes of transuranics are the zinc and calcium salts of diethylene-triamine-pentaacetic acid, better known as Zn-DTPA and Ca-DTPA. In the past 35 years, approximately 3000 doses of DTPA have been administrated to over 500 individuals who had intakes of transuranics. The drug is considered to be quiet safe and has few side effects. For the internal dosimetrist, perhaps the most important aspects of chelation therapy is that if enhances the excretion rate of a transuranic and perturbs the shape of the urinary excretion curve. These perturbations last for months and are so great that standard urinary excretion models cannot be used to evaluate the intake. We review here a method for evaluating intakes of transuranics influenced by chelation therapy that has been used with some degree of success at the Savannah River Site for over 20 years.

  1. Scintigraphic monitoring of immunotoxins using radionuclides and heterobifunctional chelators

    SciTech Connect

    Reardan, D.; Bernhard, S.

    1991-10-22

    This patent describes a method for in vivo radioimmunodetection of cytotoxic immunotoxin. It comprises administering internally to a mammal a radio-labeled immunotoxin, wherein a heterobifunctional chelating agent provides a chemical bridge between a radiolabel and a cytotoxic component bound to the antigen-binding component of the immunotoxin, and detecting externally the distribution of the immunotoxin in the mammal.

  2. Mineral Levels in Thalassaemia Major Patients Using Different Iron Chelators.

    PubMed

    Genc, Gizem Esra; Ozturk, Zeynep; Gumuslu, Saadet; Kupesiz, Alphan

    2016-03-01

    The goal of the present study was to determine the levels of minerals in chronically transfused thalassaemic patients living in Antalya, Turkey and to determine mineral levels in groups using different iron chelators. Three iron chelators deferoxamine, deferiprone and deferasirox have been used to remove iron from patients' tissues. There were contradictory results in the literature about minerals including selenium, zinc, copper, and magnesium in thalassaemia major patients. Blood samples from the 60 thalassaemia major patients (the deferoxamine group, n=19; the deferiprone group, n=20 and the deferasirox group, n=21) and the controls (n=20) were collected. Levels of selenium, zinc, copper, magnesium, and iron were measured, and all of them except iron showed no significant difference between the controls and the patients regardless of chelator type. Serum copper levels in the deferasirox group were lower than those in the control and deferoxamine groups, and serum magnesium levels in the deferasirox group were higher than those in the control, deferoxamine and deferiprone groups. Iron levels in the patient groups were higher than those in the control group, and iron levels showed a significant correlation with selenium and magnesium levels. Different values of minerals in thalassaemia major patients may be the result of different dietary intake, chelator type, or regional differences in where patients live. That is why minerals may be measured in thalassaemia major patients at intervals, and deficient minerals should be replaced. Being careful about levels of copper and magnesium in thalassaemia major patients using deferasirox seems to be beneficial. PMID:26179086

  3. Efficacy of reversal of aortic calcification by chelating agents

    PubMed Central

    Lei, Yang; Sinha, Aditi; Vyavahare, Naren

    2013-01-01

    Elastin specific medial vascular calcification, termed Monckebergs sclerosis has been recognized as a major risk factor for various cardiovascular events. We hypothesize that chelating agents, such as disodium ethylene diamine tetraacetic acid (EDTA), diethylene triamine pentaacetic acid (DTPA) and sodium thiosulfate (STS) might reverse elastin calcification by directly removing calcium (Ca) from calcified tissues into soluble calcium complexes. We assessed the chelating ability of EDTA, DTPA, and STS on removal of calcium from hydroxyapatite (HA) powder, calcified porcine aortic elastin, and calcified human aorta in vitro. We show that both EDTA and DTPA could effectively remove calcium from HA and calcified tissues, while STS was not effective. The tissue architecture was not altered during chelation. In the animal model of aortic elastin-specific calcification, we further show that local periadventitial delivery of EDTA loaded in to poly (lactic-co-glycolic acid) (PLGA) nanoparticles regressed elastin specific calcification in the aorta. Collectively, the data indicate that elastin-specific medial vascular calcification could be reversed by chelating agents. PMID:23963635

  4. Copper chelators: chemical properties and bio-medical applications.

    PubMed

    Tegoni, M; Valensin, D; Toso, L; Remelli, M

    2014-01-01

    Copper is present in different concentrations and chemical forms throughout the earth crust, surface and deep water and even, in trace amounts, in the atmosphere itself. Copper is one of the first metals used by humans, the first artifacts dating back 10,000 years ago. Currently, the world production of refined copper exceeds 16,000 tons/year. Copper is a micro-element essential to life, principally for its red-ox properties that make it a necessary cofactor for many enzymes, like cytochrome-c oxidase and superoxide dismutase. In some animal species (e.g. octopus, snails, spiders, oysters) copper-hemocyanins also act as carriers of oxygen instead of hemoglobin. However, these red-ox properties also make the pair Cu(+)/Cu(2+) a formidable catalyst for the formation of reactive oxygen species, when copper is present in excess in the body or in tissues. The treatment of choice in cases of copper overloading or intoxication is the chelation therapy. Different molecules are already in clinical use as chelators or under study or clinical trial. It is worth noting that chelation therapy has also been suggested to treat some neurodegenerative diseases or cardiovascular disorders. In this review, after a brief description of the homeostasis and some cases of dyshomeostasis of copper, the main (used or potential) chelators are described; their properties in solution, even in relation to the presence of metal or ligand competitors, under physiological conditions, are discussed. The legislation of the most important Western countries, regarding both the use of chelating agents and the limits of copper in foods, drugs and cosmetics, is also outlined. PMID:24934357

  5. Elucidating the Role of Ferrous Ion Cocatalyst in Enhancing Dilute Acid Pretreatment of Lignocellulosic Biomass

    SciTech Connect

    Wei, H.; Donohoe, B. S.; Vinzant, T. B.; Ciesielski, P. N.; Wang, W.; Gedvilas, L. M.; Zeng, Y.; Johnson, D. K.; Ding, S. Y.; Himmel, M. E.; Tucker, M. P.

    2011-01-01

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

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

    PubMed Central

    2011-01-01

    Background Recently developed iron cocatalyst enhancement of dilute acid pretreatment of biomass is a promising approach for enhancing sugar release from recalcitrant lignocellulosic biomass. However, very little is known about the underlying mechanisms of this enhancement. In the current study, our aim was to identify several essential factors that contribute to ferrous ion-enhanced efficiency during dilute acid pretreatment of biomass and to initiate the investigation of the mechanisms that result in this enhancement. Results During dilute acid and ferrous ion cocatalyst pretreatments, we observed concomitant increases in solubilized sugars in the hydrolysate and reducing sugars in the (insoluble) biomass residues. We also observed enhancements in sugar release during subsequent enzymatic saccharification of iron cocatalyst-pretreated biomass. Fourier transform Raman spectroscopy showed that major peaks representing the C-O-C and C-H bonds in cellulose are significantly attenuated by iron cocatalyst pretreatment. Imaging using Prussian blue staining indicated that Fe2+ ions associate with both cellulose/xylan and lignin in untreated as well as dilute acid/Fe2+ ion-pretreated corn stover samples. Analyses by scanning electron microscopy and transmission electron microscopy revealed structural details of biomass after dilute acid/Fe2+ ion pretreatment, in which delamination and fibrillation of the cell wall were observed. Conclusions By using this multimodal approach, we have revealed that (1) acid-ferrous ion-assisted pretreatment increases solubilization and enzymatic digestion of both cellulose and xylan to monomers and (2) this pretreatment likely targets multiple chemistries in plant cell wall polymer networks, including those represented by the C-O-C and C-H bonds in cellulose. PMID:22074910

  7. Suboptimal response to ferrous sulfate in iron-deficient patients taking omeprazole.

    PubMed

    Ajmera, Akash V; Shastri, Ghanshyam S; Gajera, Mithil J; Judge, Thomas A

    2012-05-01

    Iron deficiency anemia is commonly encountered in outpatient practice. Gastric acid is one of the important factors for optimum absorption of iron. Proton pump inhibitors are very commonly prescribed medications. One of the debated effects of proton pump inhibitors is on oral iron absorption. Their effect on absorption of oral iron supplementation in iron-deficient patients has not been studied. At the Cooper Hematology Outpatient office, we reviewed charts of iron-deficient anemic patients who were on omeprazole for the last 4 years. Fifty patients having no apparent ongoing blood loss, having other causes of anemia especially that of chronic diseases ruled out, and on omeprazole while starting ferrous sulfate therapy for iron deficiency were selected for chart review. The iron-study results at the start of oral ferrous sulfate therapy and at 3 months follow-up were compared to evaluate the response of ferrous sulfate. The mean hemoglobin change was 0.8 1.2 g/L. The mean change in ferrtin values was 10.2 7.8 ?g/L. Only 16% of the patients had a normal response to hemoglobin levels (rise of >2 g/dL), and only 40% had a normal response to ferritin levels (rise of >20 ?g/dL). The average age of patients having a suboptimal response to both hemoglobin and ferritin was significantly higher compared with that of the patients with an optimal response. Omeprazole and possibly all proton pump inhibitors decrease the absorption of oral iron supplementation. Iron-deficient patients taking proton pump inhibitors may have to be treated with high dose iron therapy for a longer duration or with intravenous iron therapy. PMID:21150767

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

    SciTech Connect

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

    2013-04-01

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

  9. Oral ferrous sulfate does not increase preoperative hemoglobin in patients scheduled for hip or knee arthroplasty.

    TOXLINE Toxicology Bibliographic Information

    Lachance K; Savoie M; Bernard M; Rochon S; Fafard J; Robitaille R; Vendittoli PA; Lvesque S; de Denus S

    2011-06-01

    BACKGROUND: Low hemoglobin (Hb) concentrations before lower limb joint replacement are associated with the need for blood transfusions and increased mortality. To optimize preoperative Hb, blood conservation protocols often recommend oral iron supplements, even in nonanemic patients.OBJECTIVE: To investigate the impact of ferrous sulfate on the change in Hb prior to hip or knee arthroplasty and evaluate the effect of oral iron on hematocrit, mean corpuscular volume (MCV), ferritin, and transferrin saturation, as well as its tolerability and treatment adherence.METHODS: We conducted a prospective, observational cohort study of adults with Hb concentrations between 10 and 15 g/dL who received iron supplementation prior to hip or knee arthroplasty. Systemic inflammatory diseases, vitamin B(12) or folate deficiency, and current use of iron supplements, intravenous iron, or erythropoietin were exclusion criteria. All participants were prescribed ferrous sulfate 300 mg 3 times daily for a minimum of 3 weeks. Complete blood cell counts and iron studies were performed before therapy and surgery.RESULTS: Eighty-seven patients with a mean (SD) Hb of 13.47 (0.84) g/dL were included in the study. Preoperative Hb decreased after treatment with iron (-0.14 [0.53] g/dL, p = 0.015). Hematocrit also declined (-0.6% [1.8%], p = 0.002), whereas ferritin increased (25.8 [38.6] ng/mL, p < 0.001). No significant change was seen in MCV and transferrin saturation. The most common adverse effects were constipation (33.3%), heartburn (13.8%), and abdominal pain (12.6%). The adherence rate was 67.1%.CONCLUSIONS: Oral ferrous sulfate supplementation is not an effective method to increase preoperative Hb in patients scheduled for hip or knee arthroplasty, and its use is associated with adverse effects.

  10. Oxygen isotope fractionation of dissolved oxygen during reduction by ferrous iron

    NASA Astrophysics Data System (ADS)

    Oba, Yasuhiro; Poulson, Simon R.

    2009-01-01

    The oxygen isotope fractionation factor of dissolved oxygen gas has been measured during inorganic reduction by aqueous FeSO 4 at 10-54 C under neutral (pH 7) and acidic (pH 2) conditions, with Fe(II) concentrations ranging up to 0.67 mol L -1, in order to better understand the geochemical behavior of oxygen in ferrous iron-rich groundwater and acidic mine pit lakes. The rate of oxygen reduction increased with increasing temperature and increasing Fe(II) concentration, with the pseudo-first-order rate constant k ranging from 2.3 to 82.9 10 -6 s -1 under neutral conditions and 2.1 to 37.4 10 -7 s -1 under acidic conditions. The activation energy of oxygen reduction was 30.9 6.6 kJ mol -1 and 49.7 13.0 kJ mol -1 under neutral and acidic conditions, respectively. Oxygen isotope enrichment factors ( ?) become smaller with increasing temperature, increasing ferrous iron concentration, and increasing reaction rate under acidic conditions, with ? values ranging from -4.5 to -11.6. Under neutral conditions, ? does not show any systematic trends vs. temperature or ferrous iron concentration, with ? values ranging from -7.3 to -10.3. Characterization of the oxygen isotope fractionation factor associated with O 2 reduction by Fe(II) will have application to elucidating the process or processes responsible for oxygen consumption in environments such as groundwater and acidic mine pit lakes, where a number of possible processes (e.g. biological respiration, reduction by reduced species) may have taken place.

  11. Pulsed ENDOR Determination of the Arginine Location in Ferrous-NO Form of Neuronal NOS

    PubMed Central

    Astashkin, Andrei V.; Elmore, Bradley O.; Chen, Li; Fan, Weihong; Guillemette, J. Guy; Feng, Changjian

    2012-01-01

    Mammalian nitric oxide synthases (NOSs) are enzymes responsible for oxidation of L-arginine (L-Arg) to nitric oxide (NO). Mechanisms of reactions at the catalytic heme site are not well understood, and it is of current interest to study structures of the heme species that activates O2 and transforms the substrate. The NOS ferrous-NO complex is a close mimic of the obligatory ferric (hydro)peroxo intermediate in NOS catalysis. In this work, pulsed electron-nuclear double resonance (ENDOR) was used to probe the position of the L-Arg substrate at the NO-coordinated ferrous heme center(s) in the oxygenase domain of rat neuronal NOS (nNOS). The analysis of 2H and 15N ENDOR spectra of samples containing D7- or guanidino-15N2 labeled L-Arg has resulted in distance estimates for the nearby guanidino nitrogen and the nearby proton (deuteron) at C?. The L-Arg position was found to be noticeably different from that in the X-ray crystal structure of nNOS ferrous-NO complex [Li et al., J. Biol. Inorg. Chem. 2006, 11, 753768], with the nearby guanidino nitrogen being ~ 0.5 closer to, and the nearby H? about 1 further from the NO ligand than in the X-ray structure. The difference might be related to the structural constraints imposed on the protein by the crystal. Importantly, in spite of its closer position, the guanidino nitrogen does not form a hydrogen bond with the NO ligand, as evidenced by the absence of significant isotropic hfi constant for Ng1. This is consistent with the previous reports that it is not the L-Arg substrate itself that would most likely serve as a direct proton donor to the diatomic ligands (NO and O2) bound to the heme. PMID:22667467

  12. Molecular mechanisms of in vivo metal chelation: implications for clinical treatment of metal intoxications.

    PubMed Central

    Andersen, Ole; Aaseth, Jan

    2002-01-01

    Successful in vivo chelation treatment of metal intoxication requires that a significant fraction of the administered chelator in fact chelate the toxic metal. This depends on metal, chelator, and organism-related factors (e.g., ionic diameter, ring size and deformability, hardness/softness of electron donors and acceptors, route of administration, bioavailability, metabolism, organ and intra/extracellular compartmentalization, and excretion). In vivo chelation is not necessarily an equilibrium reaction, determined by the standard stability constant, because rate effects and ligand exchange reactions considerably influence complex formation. Hydrophilic chelators most effectively promote renal metal excretion, but they complex intracellular metal deposits inefficiently. Lipophilic chelators can decrease intracellular stores but may redistribute toxic metals to, for example, the brain. In chronic metal-induced disease, where life-long chelation may be necessary, possible toxicity or side effects of the administered chelator may be limiting. The metal selectivity of chelators is important because of the risk of depletion of the patient's stores of essential metals. Dimercaptosuccinic acid and dimercaptopropionic sulfonate have gained more general acceptance among clinicians, undoubtedly improving the management of many human metal intoxications, including lead, arsenic, and mercury compounds. Still, development of new safer chelators suited for long-term oral administration for chelation of metal deposits (mainly iron), is an important research challenge for the future. PMID:12426153

  13. EDTA Chelation Therapy, Without Added Vitamin C, Decreases Oxidative DNA Damage and Lipid Peroxidation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chelation therapy is thought to not only remove contaminating metals, but also to decrease free radical production. However, in standard EDTA chelation therapy high doses of vitamin C with potential prooxidant effects are often added to the chelation solution. We demonstrated previously that the in...

  14. Role of chelating agents for prevention, intervention, and treatment of exposures to toxic metals

    SciTech Connect

    Goyer, R.A.; Cherian, M.G.; Jones, M.M.

    1995-11-01

    This article discusses the role of chelating agents for prevention, intervention and treatment of exposures to toxic metals. Experimental and clinical studies concerned with the effectiveness and potential toxicity of chelating agents used to reduce the body burden of various metals and to identify research needs in the area of chelation are discussed. 40 refs.

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

    NASA Technical Reports Server (NTRS)

    Miyoshi, K.; Buckley, D. H.

    1982-01-01

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

  16. Clean Ferrous Casting Technology Research. Annual report, September 29, 1993--September 28, 1994

    SciTech Connect

    Stefanescu, D.M.; Lane, A.M.; Giese, S.R.; Pattabhi, R.; El-Kaddah, N.H.; Griffin, J.; Bates, C.E.; Piwonka, T.S.

    1994-10-01

    This annual report covers work performed in the first year of research on Clean Ferrous Casting Technology Research. During this year the causes of penetration of cast iron in sand molds were defined and a program which predicts the occurrence of penetration was written and verified in commercial foundries. Calculations were made to size a reaction chamber to remove inclusions from liquid steel using electromagnetic force and the chamber was built. Finally, significant progress was made in establishing pouring practices which avoid re-oxidation of steel during pouring application of revised pouring practices have led to reduced inclusion levels in commercially poured steel castings.

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

    SciTech Connect

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

    1996-01-31

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

  18. Reproducibilty test of ferrous xylenol orange gel dose response with optical cone beam CT scanning

    NASA Astrophysics Data System (ADS)

    Jordan, K.; Battista, J.

    2004-01-01

    Our previous studies of ferrous xylenol orange gelatin gel have revealed a spatial dependence to the dose response of samples contained in 10 cm diameter cylinders. Dose response is defined as change in optical attenuation coefficient divided by the dose (units cm-1 Gy-1). This set of experiments was conducted to determine the reproducibility of our preparation, irradiation and full 3D optical cone beam CT scanning. The data provided an internal check of a larger storage time-dose response dependence study.

  19. Characterisation of the ferrous-xylenol orange-gelatin (FXG) gel dosimeter

    NASA Astrophysics Data System (ADS)

    Healy, B.; Brindha, S.; Zahmatkesh, M.; Baldock, C.

    2004-01-01

    Recent studies have used the ferrous-xylenol orange-gelatin (FXG) gel dosimeter for 3D radiation field mapping using the optical computed tomography technique. However the characterisation of the dosimetry performance of the FXG gel has not been detailed, such as the variation in dose-response of the FXG gel with changes in preparation techniques, constituent concentrations, pre-irradiation storage time, and concentrations of additives such as oxygen and saccharides. In this paper these issues are addressed with the aim of developing a standard FXG gel for future use in radiation dosimetry applications.

  20. Hydrocracking with molten zinc chloride catalyst containing 2-12% ferrous chloride

    DOEpatents

    Zielke, Clyde W. (McMurray, PA); Bagshaw, Gary H. (Library, PA)

    1981-01-01

    In a process for hydrocracking heavy aromatic polynuclear carbonaceous feedstocks to produce hydrocarbon fuels boiling below about 475.degree. C. by contacting the feedstocks with hydrogen in the presence of a molten zinc chloride catalyst and thereafter separating at least a major portion of the hydrocarbon fuels from the spent molten zinc chloride catalyst, an improvement comprising: adjusting the FeCl.sub.2 content of the molten zinc chloride to from about 2 to about 12 mol percent based on the mixture of ferrous chloride and molten zinc chloride.

  1. Ferrous Analysis.

    ERIC Educational Resources Information Center

    Straub, William A.

    1989-01-01

    Elements covered in this review include: aluminum, antimony, arsenic, bismuth, boron, calcium, carbon, chromium, cobalt, copper, hydrogen, iron, lead, magnesium, manganese, molybdenum, nickel, niobium, nitrogen, oxygen, phosphorus, platinum, rare earths, silicons, sulfur, tin, titanium, tungsten, vanadium, zinc, and zirconium. Analytical methods…

  2. Ferrous Analysis.

    ERIC Educational Resources Information Center

    Straub, William A.

    1989-01-01

    Elements covered in this review include: aluminum, antimony, arsenic, bismuth, boron, calcium, carbon, chromium, cobalt, copper, hydrogen, iron, lead, magnesium, manganese, molybdenum, nickel, niobium, nitrogen, oxygen, phosphorus, platinum, rare earths, silicons, sulfur, tin, titanium, tungsten, vanadium, zinc, and zirconium. Analytical methods

  3. High-rate acidophilic ferrous iron oxidation in a biofilm airlift reactor and the role of the carrier material.

    PubMed

    Ebrahimi, S; Fernndez Morales, F J; Kleerebezem, R; Heijnen, J J; van Loosdrecht, M C M

    2005-05-20

    In this study, the feasibility and engineering aspects of acidophilic ferrous iron oxidation in a continuous biofilm airlift reactor inoculated with a mixed culture of Acidithiobacillus ferrooxidans and Leptospirillum ferrooxidans bacteria were investigated. Specific attention was paid to biofilm formation, competition between both types of bacteria, ferrous iron oxidation rate, and gas liquid mass transfer limitations. The reactor was operated at a constant temperature of 30 degrees C and at pH values of 0-1.8. Startup of the reactor was performed with basalt carrier material. During the experiments the basalt was slowly removed and the ferric iron precipitates formed served as a biofilm carrier. These precipitates have highly suitable characteristics as a carrier material for the immobilization of ferrous iron-oxidizing bacteria and dense conglomerates were observed. Lowering the pH (0.6-1) resulted in dissolution of the ferric precipitates and induced granular sludge formation. The maximum ferrous iron oxidation rate achieved in this study was about 145 molFe(2+)/m(3).h at a hydraulic residence time of 0.25 h. Optimal treatment performance was obtained at a loading rate of 100 mol/m(3).h at a conversion efficiency as high as 98%. Fluorescent in situ hybridization (FISH) studies showed that when the reactor was operated at high ferrous iron conversion (>85%) for 1 month, the desirable L. ferrooxidans species could out-compete A. ferrooxidans due to the low Fe(2+) and high Fe(3+) concentrations. PMID:15772947

  4. Examining the fixation kinetics of chelated and non-chelated copper and the applications to micronutrient management in semiarid alkaline soils

    NASA Astrophysics Data System (ADS)

    Udeigwe, T. K.; Eichmann, M. B.; Menkiti, M. C.; Kusi, N. Y. O.

    2016-02-01

    This study examined and compared the fixation and fixation kinetics of copper (Cu) in chelated (ethylene diamine tetraacetic acid, EDTA) and non-chelated mixed systems of micronutrients in the semiarid soils of the Southern High Plains, USA, using findings from Cu extraction studies and kinetic models. Approximately, 22 % more Cu was fixed in the non-chelated system compared to the chelated within the first 14 days with only 7 % difference between the two systems by day 90. Findings suggest a decrease in the effectiveness of chelated micronutrients over time, highlighting the significance of timing even when chelated micronutrients are used. The strengths of the relationship of change in available Cu with respect to other micronutrients (iron (Fe), manganese (Mn), and zinc (Zn)) were higher in the non-chelated system (R2: 0.68-0.94), compared to the chelated (R2: 0.42-0.81), with slopes of 0.40 (Cu-Fe), 0.31 (Cu-Mn), and 1.04 (Cu-Zn) in the non-chelated system and 0.26 (Cu-Fe), 0.22 (Cu-Mn), and 0.90 (Cu-Zn) in the chelated system. Reduction in the amount of available Cu was best described by the power function model (R2 = 0.91, SE = 0.081) in the non-chelated system and second-order model (R2 = 0.95, SE = 0.010) in the chelated system. The applications generated from this study could be used as tools for improved micronutrient management and also provide baseline data for future work in other semiarid/arid alkaline soils of the world. Findings are also more applicable to field settings, an improvement over related previous studies.

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

    USGS Publications Warehouse

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

    1998-01-01

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

  6. Ferrous sulfate based low temperature synthesis and magnetic properties of nickel ferrite nanostructures

    SciTech Connect

    Tejabhiram, Y.; Pradeep, R.; Helen, A.T.; Gopalakrishnan, C.; Ramasamy, C.

    2014-12-15

    Highlights: • Novel low temperature synthesis of nickel ferrite nanoparticles. • Comparison with two conventional synthesis techniques including hydrothermal method. • XRD results confirm the formation of crystalline nickel ferrites at 110 °C. • Superparamagnetic particles with applications in drug delivery and hyperthermia. • Magnetic properties superior to conventional methods found in new process. - Abstract: We report a simple, low temperature and surfactant free co-precipitation method for the preparation of nickel ferrite nanostructures using ferrous sulfate as the iron precursor. The products obtained from this method were compared for their physical properties with nickel ferrites produced through conventional co-precipitation and hydrothermal methods which used ferric nitrate as the iron precursor. X-ray diffraction analysis confirmed the synthesis of single phase inverse spinel nanocrystalline nickel ferrites at temperature as low as 110 °C in the low temperature method. Electron microscopy analysis on the samples revealed the formation of nearly spherical nanostructures in the size range of 20–30 nm which are comparable to other conventional methods. Vibrating sample magnetometer measurements showed the formation of superparamagnetic particles with high magnetic saturation 41.3 emu/g which corresponds well with conventional synthesis methods. The spontaneous synthesis of the nickel ferrite nanoparticles by the low temperature synthesis method was attributed to the presence of 0.808 kJ mol{sup −1} of excess Gibbs free energy due to ferrous sulfate precursor.

  7. Studies with Ferrous Sulfamate and Alternate Reductants for 2nd Uranium Cycle

    SciTech Connect

    Crowder, M.L.

    2003-01-15

    A wide range of miniature mixer-settler tests were conducted to determine the source of iron and sulfur contamination in the uranium product stream (''1EU'') of H Canyon's 2nd Uranium Cycle. The problem was reproduced on the laboratory scale mixer-settlers by changing the feed location of ferrous sulfamate from stage D4 to stage D1. Other process variables effected no change. It was later determined that ferrous sulfamate (FS) solids had plugged the FS line to stage D4, causing FS to backup a ventline and enter the Canyon process at stage D1. Pluggage was almost certainly due to precipitation of FS solids during extended process downtime. During the search for the root cause, tests showed that FS solids were quite small (1-10 mm), and a portion of them could bypass the current Canyon prefilter (3-mm). Also, additional tests were done to find an alternate means of reducing and thereby removing plutonium and neptunium from the uranium product. These tests showed that FS was a more effective reductant than either ascorbic acid or a hydroxylamine nitrate (HAN) / dilute FS combination.

  8. Efficient near ultraviolet light induced formation of hydrogen by ferrous hydroxide. [in primitive earth

    NASA Technical Reports Server (NTRS)

    Borowska, Zofia K.; Mauzerall, David C.

    1987-01-01

    A possible origin of early hydrogen by UV-induced photoreduction of ferrous ions was investigated by measuring the rate of H2 formation from irradiated FeSO4 solutions as a function of pH and the range of UV sources. It was found that, in addition to the known reaction in acid solution which decreases in yield with increasing pH and requires far-UV light, there is an efficient reaction occurring between pH 6 and 9 which utilizes near-UV light (of a 200-W mercury arc lamp). This latter reaction is a linear function of both the concentration of Fe(2+) and the light intensity. These results support the suggestion of Braterman et al. (1983) that the near-UV-driven photooxidation of ferrous ions may be responsible for the origin of the banded iron formations on the early earth. The efficient photoreaction could also explain the source of reducing equivalents for CO2 reduction.

  9. Effect of ferrous and ferric ions on copigmentation in model solutions

    NASA Astrophysics Data System (ADS)

    Kunsgi-Mt, Sndor; Ortmann, Erika; Kollr, Lszl; Szab, Kornlia; Nikfardjam, Martin Pour

    2008-11-01

    The thermodynamics of the molecular association process between malvidin-3- O-glucoside and ellagic acid (so-called "copigmentation") was studied in model wine solutions in the presence and absence, respectively, of ferrous and ferric ions. The Gibbs free energy, enthalpy, and entropy values of the complexation process were determined by means of a spectrofluorometric method. A combination of the Job's method with the van't Hoff theory was used for data evaluation. The results show the generally exothermic character of the process. The free enthalpy changes obtained during formation of malvidin-3- O-glucoside-ellagic acid complexes increase from -17.8 kJ/mol to -40.5 kJ/mol in the presence of Fe(II) ions. The increased free enthalpy is a consequence of the drastic reduction of entropy change due to the slight "swinging" movement of the interacting malvidin and ellagic acid molecules in the complexes stabilized by the ferrous ions. These results are also supported by the findings of other authors stating that iron ions play an important role in the stabilization of color in the plant kingdom and various plant products.

  10. Low Frequency Spectral Density of Ferrous Heme: Perturbations Induced by Axial Ligation and Protein Insertion

    PubMed Central

    Gruia, Flaviu; Ye, Xiong; Ionascu, Dan; Kubo, Minoru; Champion, Paul M.

    2007-01-01

    Femtosecond coherence spectroscopy is used to probe low frequency (20400 cm?1) modes of the ferrous heme group in solution, with and without 2-methyl imidazole (2MeIm) as an axial ligand. The results are compared to heme proteins (CPO, P450cam, HRP, Mb) where insertion of the heme into the protein results in redistribution of the low frequency spectral density and in (?60%) longer damping times for the coherent signals. The major effect of imidazole ligation to the ferrous heme is the softening of the low frequency force constants by a factor of ?0.6 0.1. The functional consequences of imidazole ligation are assessed and it is found that the enthalpic CO rebinding barrier is increased significantly when imidazole is bound. The force constant softening analysis, combined with the kinetics results, indicates that the iron is displaced by only ?0.2 from the heme plane in the absence of the imidazole ligand, whereas it is displaced by ?0.4 when imidazole (histidine) is present. This suggests that binding of imidazole (histidine) as an axial ligand, and the concomitant softening of the force constants, leads to an anharmonic distortion of the heme group that has significant functional consequences. PMID:17766351

  11. Ettringite-induced heave in chromite ore processing residue (COPR) upon ferrous sulfate treatment.

    PubMed

    Dermatas, Dimitris; Chrysochoou, Maria; Moon, Deok Hyun; Grubb, Dennis G; Wazne, Mahmoud; Christodoulatos, Christos

    2006-09-15

    A pilot-scale treatment study was implemented at a deposition site of chromite ore processing residue (COPR) in New Jersey. Ferrous sulfate heptahydrate (FeSO4 x 7H2O) was employed to reduce hexavalent chromium in two dosages with three types of soil mixing equipment. XANES analyses of treated samples cured for 240 days indicated that all treatment combinations failed to meet the Cr(VI) regulatory limit of 240 mg/kg. More importantly, the discrepancy between XANES and alkaline digestion results renders the latter unreliable for regulatory purposes when applied to ferrous-treated COPR. Regardless of Cr-(VI), the introduction of reductant containing sulfate, mechanical mixing, water, acidity, and the resulting temperature increase in treated COPR promoted dissolution of brownmillerite (Ca2FeAlO5), releasing alumina and alkalinity. The pH increase caused initially precipitated gypsum (CaSO4 x 2H2O) to progressively convert to ettringite (Ca6Al2(SO4)3 x 32H2O) and its associated volume expansion under both in situ and ex situ conditions, with a maximum of 0.8 m vertical swell within 40 days of curing. While Cr-(VI) treatment remains a challenge, the intentional exhaustion of the heave potential of COPR by transforming all Al sources to ettringite emerges as a possible solution to delayed ettringite formation, which would hamper site redevelopment. PMID:17007141

  12. A ferrous oxalate mediated photo-Fenton system: toward an increased biodegradability of indigo dyed wastewaters.

    PubMed

    Vedrenne, Michel; Vasquez-Medrano, Ruben; Prato-Garcia, Dorian; Frontana-Uribe, Bernardo A; Hernandez-Esparza, Margarita; de Andrés, Juan Manuel

    2012-12-01

    This study assessed the applicability of a ferrous oxalate mediated photo-Fenton pretreatment for indigo-dyed wastewaters as to produce a biodegradable enough effluent, likely of being derived to conventional biological processes. The photochemical treatment was performed with ferrous oxalate and hydrogen peroxide in a Compound Parabolic Concentrator (CPC) under batch operation conditions. The reaction was studied at natural pH conditions (5-6) with indigo concentrations in the range of 6.67-33.33 mg L(-1), using a fixed oxalate-to-iron mass ratio (C(2)O(4)(2-)/Fe(2+)=35) and assessing the system's biodegradability at low (257 mg L(-1)) and high (1280 mg L(-1)) H(2)O(2) concentrations. In order to seek the optimal conditions for the treatment of indigo dyed wastewaters, an experimental design consisting in a statistical surface response approach was carried out. This analysis revealed that the best removal efficiencies for Total Organic Carbon (TOC) were obtained for low peroxide doses. In general it was observed that after 20 kJ L(-1), almost every treated effluent increased its biodegradability from a BOD(5)/COD value of 0.4. This increase in the biodegradability was confirmed by the presence of short chain carboxylic acids as intermediate products and by the mineralization of organic nitrogen into nitrate. Finally, an overall decrease in the LC(50) for Artemia salina indicated a successful detoxification of the effluent. PMID:23142056

  13. Ferrous alloy metallurgy, liquid lithium corrosion and welding. Final report, April 1, 1973-March 31, 1984

    SciTech Connect

    Olson, D.L.; Matlock, D.K.

    1984-01-01

    This research program consists of two parts: an evaluation of the corrosion behavior of ferrous alloys in liquid lithium, and a study of microstructure development and properties of dissimilar metal weldments. A ten-year overview of the research accomplishments made is presented. The effects of liquid lithium on both uniform corrosion and grain boundary penetration in ferrous alloys has been investigated as a function of time, temperature, base metal alloy content, and liquid lithium nitrogen content. Kinetic equations for the various corrosion processes have been developed and analyzed with respect to models for corrosion and corrosion product development. The effects of liquid lithium on mechanical properties, particularly fatigue, have been studied. Results have shown that in both austenitic stainless steels and ferritic steels, liquid lithium significantly reduces the mechanical integrity of all materials by inducing liquid metal embrittlement. A model for liquid metal embrittlement induced damage during fatigue was developed and shown to correlate with the experimental results. Microstructural development in austenitic weld metal, with particular emphasis on new grades with reduced chromium contents, has been investigated. The microstructures have been correlated with alloy content and the basics of a thermodynamic model for predicting weld metal microstructure has been developed. The high temperature mechanical behavior of dissimilar metal weldments (austenitic stainless steel to ferritic steel) has been investigated with the impression-creep test technique. Observed microstructural changes with position across the weldment are shown to correlate directly with creep behavior. A model based on deformation of composite materials was developed.

  14. Oxidation of elemental sulfur, tetrathionate and ferrous iron by the psychrotolerant Acidithiobacillus strain SS3.

    PubMed

    Kupka, Daniel; Liljeqvist, Maria; Nurmi, Pauliina; Puhakka, Jaakko A; Tuovinen, Olli H; Dopson, Mark

    2009-12-01

    Mesophilic iron and sulfur-oxidizing acidophiles are readily found in acid mine drainage sites and bioleaching operations, but relatively little is known about their activities at suboptimal temperatures and in cold environments. The purpose of this work was to characterize the oxidation of elemental sulfur (S(0)), tetrathionate (S4O6(2-)) and ferrous iron (Fe2+) by the psychrotolerant Acidithiobacillus strain SS3. The rates of elemental sulfur and tetrathionate oxidation had temperature optima of 20 degrees and 25 degrees C, respectively, determined using a temperature gradient incubator that involved narrow (1.1 degrees C) incremental increases from 5 degrees to 30 degrees C. Activation energies calculated from the Arrhenius plots were 61 and 89 kJ mol(-1) for tetrathionate and 110 kJ mol(-1) for S(0) oxidation. The oxidation of elemental sulfur produced sulfuric acid at 5 degrees C and decreased the pH to approximately 1. The low pH inhibited further oxidation of the substrate. In media with both S(0) and Fe2+, oxidation of elemental sulfur did not commence until all available ferrous iron was oxidized. These data on sequential oxidation of the two substrates are in keeping with upregulation and downregulation of several proteins previously noted in the literature. Ferric iron was reduced to Fe2+ in parallel with elemental sulfur oxidation, indicating the presence of a sulfur:ferric iron reductase system in this bacterium. PMID:19782750

  15. Degradation kinetics of TNT in the presence of six mineral surfaces and ferrous iron.

    PubMed

    Nefso, E K; Burns, S E; McGrath, C J

    2005-08-31

    Trinitrotoluene (TNT), a nitroaromatic explosive, is a commonly encountered groundwater contaminant in the United States that can pose a human health risk, even at very low aqueous concentrations. This study describes the process characteristics of abiotic degradation of dissolved TNT in the presence of ferrous iron (Fe2+) and six different minerals-processes relevant to a more complete understanding of reduced iron technologies in TNT cleanup. Kinetic degradation batch reactions involving combinations of TNT, ferrous iron, six minerals with varying cation exchange capacity, and two pH buffers were performed. The rate of TNT degradation was quantified using high performance liquid chromatography (HPLC). Unbuffered reactions between TNT, Fe2+, and magnetite, pyrite, quartz, and goethite/quartz were insignificant. However, unbuffered reactions between TNT, Fe2+, and calcite and siderite proceeded rapidly to completion. The difference in reaction rates was attributable to the elevated pH in the presence of the latter minerals. For reactions performed in buffered systems with pH 7.4, degradation followed a second-order kinetics rate law. For reactions in buffered systems with pH 9.0, the reactions proceeded to completion almost instantaneously. The presence of the mineral solid surface was necessary for TNT reduction to proceed, with the most rapid reaction rates occurring in the presence of a suspected hydroxy solid phase that formed at high pH. PMID:15961226

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

    NASA Astrophysics Data System (ADS)

    Mauzerall, David C.

    1990-05-01

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

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

    NASA Technical Reports Server (NTRS)

    Mauzerall, David C.

    1990-01-01

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

  18. Degradation of trichloroethylene in aqueous solution by calcium peroxide activated with ferrous ion.

    PubMed

    Zhang, Xiang; Gu, Xiaogang; Lu, Shuguang; Miao, Zhouwei; Xu, Minhui; Fu, Xiaori; Qiu, Zhaofu; Sui, Qian

    2015-03-01

    The application of calcium peroxide (CaO2) activated with ferrous ion to stimulate the degradation of trichloroethylene (TCE) was investigated. The experimental results showed that TCE could be completely degraded in 5 min at a CaO2/Fe(II)/TCE molar ratio of 4/8/1. Probe compound tests demonstrated the presence of reactive oxygen species HO and O2(-) in CaO2/Fe(II) system, while scavenging tests indicated that HO was the dominant active species responsible for TCE removal, and O2(-) could promote TCE degradation in CaO2/Fe(II) system. In addition, the influences of initial solution pH and solution matrix were evaluated. It suggested that the elevation of initial solution pH suppressed TCE degradation. Cl(-) had significant scavenging effect on TCE removal, whereas HCO3(-) of high concentration showed favorable function. The influences of NO3(-) and SO4(2-) could be negligible, while natural organic matter (NOM) had a negative effect on TCE removal at a relatively high concentration. The results demonstrated that the technique of CaO2 activated with ferrous ion is a highly promising technique in in situ chemical oxidation (ISCO) remediation in TCE contaminated sites. PMID:25463240

  19. Ferrous and ferric ions-based high-throughput screening strategy for nitrile hydratase and amidase.

    PubMed

    Lin, Zhi-Jian; Zheng, Ren-Chao; Lei, Li-Hua; Zheng, Yu-Guo; Shen, Yin-Chu

    2011-06-01

    Rapid and direct screening of nitrile-converting enzymes is of great importance in the development of industrial biocatalytic process for pharmaceuticals and fine chemicals. In this paper, a combination of ferrous and ferric ions was used to establish a novel colorimetric screening method for nitrile hydratase and amidase with α-amino nitriles and α-amino amides as substrates, respectively. Ferrous and ferric ions reacted sequentially with the cyanide dissociated spontaneously from α-amino nitrile solution, forming a characteristic deep blue precipitate. They were also sensitive to weak basicity due to the presence of amino amide, resulting in a yellow precipitate. When amino amide was further hydrolyzed to amino acid, it gave a light yellow solution. Mechanisms of color changes were further proposed. Using this method, two isolates with nitrile hydratase activity towards 2-amino-2,3-dimethyl butyronitrile, one strain capable of hydrating 2-amino-4-(hydroxymethyl phosphiny) butyronitrile and another microbe exhibiting amidase activity against 2-amino-4-methylsulfanyl butyrlamide were obtained from soil samples and culture collections of our laboratory. Versatility of this method enabled it the first direct and inexpensive high-throughput screening system for both nitrile hydratase and amidase. PMID:21420446

  20. Aluminum chelation: chemistry, clinical, and experimental studies and the search for alternatives to desferrioxamine.

    PubMed

    Yokel, R A

    1994-02-01

    This review focuses on aluminum (Al) chelation, its chemistry and biology. The toxicology and biology of Al in mammalian organisms are briefly reviewed to introduce the problems associated with excessive Al exposure and accumulation and the challenges facing an effective Al chelator. The basics of Al chelation chemistry are considered to help the reader understand the Al chelation chemical literature. The chemical properties of Al enable prediction of effective functional groups for Al chelation. A compilation of distribution coefficients between octanol and aqueous phases (Do/a) for chelators and their complexes with Al shows the effect of complexation on lipophilicity. A compilation of stability constants for Al.chelator complexes illustrates the role of oxygen in ligands that form stable complexes. The history of clinical Al chelation therapy is reviewed, with emphasis on desferrioxamine (DFO), which has been extensively used since 1980. The beneficial and adverse effects and limitations of DFO use in end-stage renal-diseased patients, in patients with neurodegenerative disorders, including Alzheimer's disease, and in animal models of Al intoxication are presented. The methods to evaluate potential Al chelators in vitro, in vivo, and using computer modeling are discussed. The Al chelation literature is reviewed by the chemical class of chelators, including fluoride, carboxylic acids, amino acids, catechols, polyamino carboxylic acids, phenyl carboxylic acids, the hydroxypyridinones, and hydroxamic acids. PMID:8301696

  1. Chemical Fixation of Trace Elements in Coal Fly Ash using Ferrous Sulfate Treatment

    NASA Astrophysics Data System (ADS)

    Bhattacharyya, S.; Donahoe, R. J.

    2008-12-01

    Coal fired electric power plants produce 50% of the electricity consumed in the US and generate large volumes of fly ash and other coal combustion by-products (CCBs). The majority of the CCB materials are disposed of in surface impoundments and landfills located throughout the US. Fly ash contains trace elements such as As, B, Cr, Mo, Ni, Se, Sr and V which can have a negative impact on the environment due to leaching by acid rain and groundwater with time. The potential release of these toxic trace elements into the environment is a big concern for the US power industry due to the high cost involved in lining the old and existing ash disposal sites. As a result, simple and effective treatment techniques are needed to stabilize the coal combustion by-products produced by power plants in the ash disposal sites and also to increase the use of coal fly ash for beneficial purposes. This paper reports the results of batch experiments designed to chemically treat coal fly ash with ferrous sulfate solution by promoting the formation of insoluble iron oxy- hydroxide phases that immobilize the toxic trace elements. Four fly ash samples, three acidic (HA, HB and MA) and one alkaline (PD), were treated with a ferrous sulfate (FS) solution (322 ppm Fe) and a ferrous sulfate + calcium carbonate (FS+CC) solution (322 ppm Fe and 28 ppm CaCO3) at solid:liquid ratios of 1:3 and 1:30. The effectiveness of this treatment technique was evaluated by the batch sequential leaching of treated and untreated coal fly ash samples using a synthetic acid rain (SAR) solution (USEPA Method 1312B) and also by a 7-step sequential chemical extraction procedure (SCEP) to understand the mechanism of treatment. The unbuffered FS solution at the 1:30 ratio was highly successful in reducing the mobility of the oxyanionic trace elements As (24-91%), Cr (82-97%), Mo (79-100%), Se (41-87%) and V (55-100%). However, the unbuffered FS treatment failed to reduce the mobility of B, Ni and Sr for the acidic fly ash samples. The buffered FS + CC solution greatly increased the mobility of the oxyanionic trace elements in the acidic fly ash samples, except for Cr in HA and HB fly ash. The buffered FS+CC solution reduced the mobility of all the trace elements except Ni in the alkaline PD fly ash. The ferrous sulfate treatment can be applied directly to the fresh fly ash produced in the electric power plants as well as to the fly ash already placed in the ash disposal facilities. A preliminary estimate indicates that ferrous sulfate treatment of fly ash at a power plant would be cost effective.

  2. Fractionation and identification of Alaska pollock skin collagen-derived mineral chelating peptides.

    PubMed

    Guo, Lidong; Harnedy, Pdraign A; O'Keeffe, Martina B; Zhang, Li; Li, Bafang; Hou, Hu; FitzGerald, Richard J

    2015-04-15

    Peptides with the ability to chelate dietary minerals have been reported to have potential as functional food ingredients. A collagen tryptic hydrolysate (CTH), previously shown to chelate iron, was further investigated for the presence of Ca, Fe and Cu chelating peptides. Sequential purification steps, including immobilised metal affinity chromatography (IMAC) and gel permeation chromatography (GPC) were employed for the separation of chelating peptides. GPC analysis showed that the mineral chelating peptides were mainly between 500 and 2000 Da. Subsequent identification was carried out using UPLC-ESI-QTOF MS/MS. Overall, 10 sequences were identified as potential chelating peptides. The Ca, Fe and Cu chelating activity of GPAGPHGPPG was 11.522.23 nmol/?mol, 1.710.17 nmol/?mol and 0.430.02 ?mol/?mol, respectively. This study identifies collagen as a good source of peptides with potential applications as functional ingredients in the management of mineral deficiencies. PMID:25466056

  3. Synthesis and evaluation of iron chelators with masked hydrophilic moieties.

    PubMed

    Meijler, Michael M; Arad-Yellin, Rina; Cabantchik, Z Ioav; Shanzer, Abraham

    2002-10-30

    Synthetic iron chelators based on the natural siderophore ferrichrome have previously been shown to bind Fe(III) with high affinity (pKf > 27) and have shown no toxicity to mammalian cell cultures in vitro. A new class of lipophilic ferrichrome analogues carrying acetoxymethyl ester moieties has been synthesized. We have shown that these molecules penetrate rapidly through cell membranes and turn highly hydrophilic while inside the cells, upon esterase mediated hydrolysis of the lipophilic termini. The intracellular retention was visualized by labeling these analogues with a fluorescent naphthalic diimide probe. The prohydrophilic iron chelators have been shown to inhibit the metal-catalyzed intracellular formation of reactive oxygen species with high effectivity, and preliminary results suggest these molecules to be potent antimalarial agents. PMID:12392406

  4. Nanomagnetic chelators for removal of toxic metal ions

    NASA Astrophysics Data System (ADS)

    Singh, Sarika; Barick, K. C.; Bahadur, D.

    2013-02-01

    Ethylenediamine trtraaceteic acid (EDTA) functionalized Fe3O4 nanomagnetic chelators (NMCs) were synthesized by co-precipitation method followed by in-situ grafting of EDTA. XRD and TEM analyses reveal the formation of highly crystalline single-phase Fe3O4 nanoparticles of size about 10 nm. Surface functionalization of Fe3O4 with EDTA was evident from FTIR spectroscopy, TGA analysis and zeta-potential measurement. These NMCs exhibit superparamagnetic behavior at room temperature with strong field dependent magnetic responsivity. It has been observed that NMCs have strong tendency for adsorption of various toxic metal ions (Ni2+, Cr3+, Cu2+, Cd2+, Co2+ and Pb2+) from waste-water. Furthermore, these magnetic chelators can be used as highly efficient separable and reusable material for removal of toxic metal ions.

  5. Doping of graphene nanomeshes by ion-chelation

    NASA Astrophysics Data System (ADS)

    Maarouf, Ahmed; Nistor, Razvan; Afzali, Ali; Kuroda, Marcelo; Newns, Dennis; Martyna, Glenn

    2013-03-01

    Graphene nanomeshes (GNM's) are formed by the creation of a superlattice of pores in graphene. Depending upon the pore shape, size, superlattice constant and symmetry, GNM's can be semimetallic, or semiconducting with a fractional eV band gap, allowing them to be fruitfully employed in applications that pristine graphene cannot. In this work, first principles calculations are used to study the doping of semiconducting GNM's using a chemically motivated approach. It is shown that ion-chelation leads to a stable doping of the GNM's, and that it occurs within a rigid band doping picture. Such chelated or ``crown'' GNM structures are thus stable, high mobility semiconducting materials which can serve as building blocks for novel graphene-based nanoelectronics applications.

  6. Improved paramagnetic chelate for molecular imaging with MRI

    NASA Astrophysics Data System (ADS)

    Winter, Patrick; Athey, Phillip; Kiefer, Garry; Gulyas, Gyongyi; Frank, Keith; Fuhrhop, Ralph; Robertson, David; Wickline, Samuel; Lanza, Gregory

    2005-05-01

    The relaxivity and transmetallation of two lipophilic paramagnetic chelates incorporated onto perfluorocarbon nanoparticles, i.e., gadolinium-methoxy-tetraazacyclododecane-tetraacetic acid phosphatidylethanolamine (Gd-MeO-DOTA-PE) and gadolinium-methoxy-tetraazacyclododecane-tetraacetic acid triglycine phosphatidylethanolamine (Gd-MeO-DOTA-triglycine-PE (Gd-MeO-DOTA-triglycine-PE)), were compared to a prototypic gadolinium-diethylene-triamine-pentaacetic acid bis-oleate (Gd-DTPA-BOA) paramagnetic formulation. Nanoparticles with MeO-DOTA-based chelates demonstrated higher relaxivity (40% higher for Gd-MeO-DOTA-PE and 55% higher for Gd-MeO-DOTA-triglycine-PE) and less transmetallation than the original Gd-DTPA-BOA-based agent.

  7. Lanthanides caged by the organic chelates; structural properties

    NASA Astrophysics Data System (ADS)

    Smentek, Lidia

    2011-04-01

    The structure, in particular symmetry, geometry and morphology of organic chelates coordinated with the lanthanide ions are analyzed in the present review. This is the first part of a complete presentation of a theoretical description of the properties of systems, which are widely used in technology, but most of all, in molecular biology and medicine. The discussion is focused on the symmetry and geometry of the cages, since these features play a dominant role in the spectroscopic activity of the lanthanides caged by organic chelates. At the same time, the spectroscopic properties require more formal presentation in the language of Racah algebra, and deserve a separate analysis. In addition to the parent systems of DOTA, DOTP, EDTMP and CDTMP presented here, their modifications by various antennas are analyzed. The conclusions that have a strong impact upon the theory of the energy transfer and the sensitized luminescence of these systems are based on the results of numerical density functional theory calculations.

  8. Removal of cadmium from fish sauce using chelate resin.

    PubMed

    Sasaki, Tetsuya; Araki, Ryohei; Michihata, Toshihide; Kozawa, Miyuki; Tokuda, Koji; Koyanagi, Takashi; Enomoto, Toshiki

    2015-04-15

    Fish sauce that is prepared from squid organs contains cadmium (Cd), which may be present at hazardous concentrations. Cd molecules are predominantly protein bound in freshly manufactured fish sauce, but are present in a liberated form in air-exposed fish sauce. In the present study, we developed a new method for removing both Cd forms from fish sauce using chelate resin and a previously reported tannin treatment. Sixteen-fold decreases in Cd concentrations were observed (0.78-0.05 mg/100 mL) following the removal of liberated Cd using chelate resin treatment, and the removal of protein-bound Cd using tannin treatment. Major nutritional components of fish sauce were maintained, including free amino acids and peptides, and angiotensin I-converting enzyme inhibitory and antioxidant activities. PMID:25466035

  9. MULTIDENTATE TEREPHTHALAMIDATE AND HYDROXYPYRIDONATE LIGANDS: TOWARDS NEW ORALLY ACTIVE CHELATORS

    SciTech Connect

    Abergel, Rebecca J.; Raymond, Kenneth N.

    2011-07-13

    The limitations of current therapies for the treatment of iron overload or radioisotope contamination have stimulated efforts to develop new orally bioavailable iron and actinide chelators. Siderophore-inspired tetradentate, hexadentate and octadentate terephthalamidate and hydroxypyridonate ligands were evaluated in vivo as selective and efficacious iron or actinide chelating agents, with several metal loading and ligand assessment procedures, using {sup 59}Fe, {sup 238}Pu, and {sup 241}Am as radioactive tracers. The compounds presented in this study were compared to commercially available therapeutic sequestering agents [deferoxamine (DFO) for iron and diethylenetriaminepentaacetic acid (DPTA) for actinides] and are unrivaled in terms of affinity, selectivity and decorporation efficacy, which attests to the fact that high metal affinity may overcome the low bioavailability properties commonly associated to multidenticity.

  10. A Novel Antimycobacterial Compound Acts as an Intracellular Iron Chelator

    PubMed Central

    Dragset, Marte S.; Poce, Giovanna; Alfonso, Salvatore; Padilla-Benavides, Teresita; Ioerger, Thomas R.; Kaneko, Takushi; Sacchettini, James C.; Biava, Mariangela; Parish, Tanya; Argello, Jos M.

    2015-01-01

    Efficient iron acquisition is crucial for the pathogenesis of Mycobacterium tuberculosis. Mycobacterial iron uptake and metabolism are therefore attractive targets for antitubercular drug development. Resistance mutations against a novel pyrazolopyrimidinone compound (PZP) that is active against M. tuberculosis have been identified within the gene cluster encoding the ESX-3 type VII secretion system. ESX-3 is required for mycobacterial iron acquisition through the mycobactin siderophore pathway, which could indicate that PZP restricts mycobacterial growth by targeting ESX-3 and thus iron uptake. Surprisingly, we show that ESX-3 is not the cellular target of the compound. We demonstrate that PZP indeed targets iron metabolism; however, we found that instead of inhibiting uptake of iron, PZP acts as an iron chelator, and we present evidence that the compound restricts mycobacterial growth by chelating intrabacterial iron. Thus, we have unraveled the unexpected mechanism of a novel antimycobacterial compound. PMID:25645825

  11. Multidentate terephthalamidate and hydroxypyridonate ligands: towards new orally active chelators.

    PubMed

    Abergel, Rebecca J; Raymond, Kenneth N

    2011-01-01

    The limitations of current therapies for the treatment of iron overload or radioisotope contamination have stimulated efforts to develop new orally bioavailable iron and actinide chelators. Siderophore-inspired tetradentate, hexadentate and octadentate terephthalamidate and hydroxypyridonate ligands were evaluated in vivo as selective and efficacious iron or actinide chelating agents, with several metal loading and ligand assessment procedures, using (59)Fe, (238)Pu, and (241)Am as radioactive tracers. The compounds presented in this study were compared to commercially available therapeutic sequestering agents [deferoxamine (DFO) for iron and diethylenetriaminepentaacetic acid (DPTA) for actinides] and are unrivaled in terms of affinity, selectivity and decorporation efficacy, which attests to the fact that high metal affinity may overcome the low bioavailability properties commonly associated to multidenticity. PMID:21599440

  12. Metal-chelate affinity precipitation of proteins using responsive polymers.

    PubMed

    Mattiasson, Bo; Kumar, Ashok; Ivanov, Alexander E; Galaev, Igor Y

    2007-01-01

    Affinity precipitation of proteins uses polymers capable of reversible soluble-insoluble transitions in response to small environmental changes (temperature, pH or solvent composition). Here we describe protocols for (i) the synthesis of responsive polymers with specific affinity to target proteins and (ii) the purification of proteins using these polymers. The purification is based on precipitation of the affinity complex between the protein and the polymer, which is induced by environmental changes. This separation strategy is simpler and more cost effective than conventional affinity column chromatography. Specifically, we describe the synthesis of thermoresponsive 1-vinylimidazole:N-isopropylacrylamide copolymers. The whole procedure takes 2-3 h when applied to purification of recombinant His-tag proteins or proteins with natural metal binding groups by means of metal chelate affinity precipitation. Optimization of the polymer composition and the type of chelating ions allows for target protein yields of 80% and higher. PMID:17401356

  13. Dose response of ferrous-xylenol orange gels: the effects of gel substrate, gelation time and dose fractionation

    NASA Astrophysics Data System (ADS)

    Jordan, K.; Battista, J.

    2004-01-01

    Investigations of the dose dependent change in optical transmission, dose response, for radiochromic ferrous-xylenol orange-gelatin gels (FXG) 3D optical CT scanning has revealed that gelation time, temperature, and dose fractionation affect the dose response (Δμ/Δdose). Correction for these factors is important for developing a reproducible dosimeter that can be reliably calibrated and used clinically. The purpose of this report is to examine trends in dose response changes for the following parameters: gelation time-temperature, concentrations of ferrous ion and xylenol orange (XO), dose range and dose fractionation.

  14. Chelate-Assisted Heavy Metal Movement Through the Root Zone

    NASA Astrophysics Data System (ADS)

    Kirkham, M.; Madrid, F.; Liphadzi, M. S.

    2001-12-01

    Chelating agents are added to soil as a means to mobilize heavy metals for plant uptake during phytoremediation. Yet almost no studies follow the displacement of heavy metals through the vadose zone following solubilization with chelating agents. The objective of this work was to determine the movement of heavy metals through the soil profile and their absorption by barley (Hordeum vulgare L.) in a soil amended with biosolids and in the presence of a chelating agent (EDTA). Twelve columns 75 cm in height and 17 in diameter were packed with a Haynie very fine sandy loam (coarse-silty, mixed, calcareous, mesic Mollic Udifluvents) and watered with liquid biosolids applied at the surface at a rate of 120 kg N/ha. Three weeks after plants germinated, soil was irrigated with a solution of the disodium salt of EDTA added at a rate of 0.5 g/kg soil. Four treatments were imposed: columns with no plants and no EDTA; columns with no plants plus EDTA; columns with plants and no EDTA; and columns with plants and EDTA. Columns were watered intensively for 35 days until two pore volumes of water had been added, and the leachates were collected daily. With or without plants, columns with EDTA had lower total concentrations of Cu, Zn, Cd, Ni, and Pb in the surface 20 cm than columns without EDTA. Concentrations of the heavy metals in this layer were not afffected by the presence of roots. Iron in leachate was followed as an indicator metal for movement to groundwater. No iron appeared in the leachate without EDTA, either in the columns with plants or without plants. The peak concentration of iron in the leachate occurred three days earlier in the columns without plants and EDTA compared to the columns with plants and EDTA. The results indicated the importance of vegetation on retarding heavy metal leaching to groundwater during chelate-facilitated phytoremediation.

  15. Reaction of gadolinium chelates with ozone and hydroxyl radicals.

    PubMed

    Cyris, Maike; Knolle, Wolfgang; Richard, Jessica; Dopp, Elke; von Sonntag, Clemens; Schmidt, Torsten C

    2013-09-01

    Gadolinium chelates are used in increasing amounts as contrast agents in magnetic resonance imaging, and their fate in wastewater treatment has recently become the focus of research. Oxidative processes, in particular the application of ozone, are currently discussed or even implemented for advanced wastewater treatment. However, reactions of the gadolinium chelates with ozone are not yet characterized. In this study, therefore, rate constants with ozone were determined for the three commonly used chelates Gd-DTPA, Gd-DTPA-BMA, and Gd-BT-DO3A, which were found to be 4.8 0.88, 46 2.5, and 24 1.5 M(-1) s(-1), respectively. These low rate constants indicate that a direct reaction with ozone in wastewater is negligible. However, application of ozone in wastewater leads to substantial yields of ()OH. Different methods have been applied and compared for determination of k(()OH+Gdchelate). From rate constants determined by pulse radiolysis experiments (k(()OH+Gd-DTPA) = 2.6 0.2 10(9) M(-1) s(-1), k(()OH+Gd-DTPA-BMA) = 1.9 0.7 10(9) M(-1) s(-1), k(()OH+Gd-BT-DO3A) = 4.3 0.2 10(9) M(-1) s(-1)), it is concluded that a reaction in wastewater via ()OH radicals is feasible. Toxicity has been tested for educt and product mixtures of both reactions. Cytotoxicity (MTT test) and genotoxicity (micronuclei assay) were not detectable. PMID:23888885

  16. Flue gas desulfurization/denitrification using metal-chelate additives

    DOEpatents

    Harkness, J.B.L.; Doctor, R.D.; Wingender, R.J.

    1985-08-05

    A method of simultaneously removing SO/sub 2/ and NO from oxygen-containing flue gases resulting from the combustion of carbonaceous material by contacting the flue gas with an aqueous scrubber solution containing an aqueous sulfur dioxide sorbent and an active metal chelating agent which promotes a reaction between dissolved SO/sub 2/ and dissolved NO to form hydroxylamine N-sulfonates. The hydroxylamine sulfonates are then separated from the scrubber solution which is recycled. 3 figs.

  17. Flue gas desulfurization/denitrification using metal-chelate additives

    DOEpatents

    Harkness, John B. L. (Naperville, IL); Doctor, Richard D. (Glen Ellyn, IL); Wingender, Ronald J. (Deerfield, IL)

    1986-01-01

    A method of simultaneously removing SO.sub.2 and NO from oxygen-containing flue gases resulting from the combustion of carbonaceous material by contacting the flue gas with an aqueous scrubber solution containing an aqueous sulfur dioxide sorbent and an active metal chelating agent which promotes a reaction between dissolved SO.sub.2 and dissolved NO to form hydroxylamine N-sulfonates. The hydroxylamine sulfonates are then separated from the scrubber solution which is recycled.

  18. New building blocks or dendritic pseudopeptides for metal chelating.

    PubMed

    Ruan, Min; Nicolas, Irène; Baudy-Floc'h, Michèle

    2016-01-01

    Dendritic oligopeptides have been reported as useful building blocks for many interactions. Starting from hydrazine, we described an approach to create new dendritic pseudopeptides linked with biological systems, such as cell membrane, as chelate metal, Ni(2+)-nitrilotriacetic acid moieties which could target histidine rich peptides or proteins. Depending on the nature of these new chemical recognition units, they could be integrated into a peptide by coupling in C or N-termini.Graphical abstract:Dendrimer formation. PMID:26835235

  19. Examining the fixation kinetics of chelated and non-chelated copper micronutrient and the applications to micronutrient management in semi-arid alkaline soils

    NASA Astrophysics Data System (ADS)

    Udeigwe, T. K.; Eichmann, M. B.; Menkiti, M. C.

    2015-10-01

    The relationship between the deficiency of a nutrient in plants and its total concentration in the soil is complex. This study examined and compared the fixation and fixation kinetics of copper (Cu) in chelated (Ethylene diamine tetraacetic acid, EDTA) and non-chelated mixed systems of micronutrients in the semi-arid soils of the Southern High Plains, US using findings from Cu extraction studies and kinetic models. Approximately, 22 % more Cu was fixed in the non-chelated system within the first 14 days with only 7 % difference between the two systems by day 90. Findings suggest a decrease in the effectiveness of chelated micronutrient over time, highlighting the significance of timing even when chelated micronutrients are applied. The strengths of the relationship of change in available Cu with respect to other micronutrients [iron (Fe), manganese (Mn), and zinc (Zn)] were higher in the non-chelated system (R2: 0.68-0.94), compared to the chelated (R2: 0.42-0.81) with slopes of 0.40 (Cu-Fe), 0.31 (Cu-Mn), and 1.04 (Cu-Zn) in the non-chelated system and 0.26 (Cu-Fe), 0.22 (Cu-Mn), and 0.90 (Cu-Zn) in the chelated. Reduction in the amount of available Cu was best described by the power function model (R2 = 0.91, SE = 0.081) in the non-chelated system and second order model (R2 = 0.95, SE = 0.010) in the chelated system. The applications generated from this study could be used as tools for improved micronutrient management and also provide baseline data for future work in other semi-arid/arid alkaline soils of the world. Findings are also more applicable to field settings, an improvement over related previous studies.

  20. Copper and Zinc Chelation as a Treatment of Alzheimer's Disease

    NASA Astrophysics Data System (ADS)

    Hodak, Miroslav; Bernholc, Jerry

    2014-03-01

    Alzheimer's disease (AD) is a neurodegenerative disorder affecting millions of people in the U.S. The cause of the disease remains unknown, but amyloid- ? (A ?), a short peptide, is considered causal its pathogenesis. At cellular level, AD is characterized by deposits mainly composed of A ? that also contain elevated levels of transition metals ions. Targeting metals is a promising new strategy for AD treatment, which uses moderately strong metal chelators to sequester them from A ? or the environment. PBT2 is a chelating compound that has been the most promising in clinical trials. In our work, we use computer simulations to investigate complexes of a close analog of PBT2 with Cu2+ and Zn2+ ions. The calculations employ KS/FD DFT method, which combines Kohn-Sham DFT with the frozen-density DFT to achieve efficient description of explicit solvent beyond the first solvation shell. Our work is based on recent experiments and examines both 1:1 and 2:1 chelator-metal stochiometries detected experimentally. The results show that copper attaches more strongly than zinc, find that 1:1 complexes involve water in the first coordination shell and determine which one of several possible 2:1 geometries is the most preferable.

  1. Prevention by chelating agents of metal-induced developmental toxicity.

    PubMed

    Domingo, J L

    1995-01-01

    Chelating agents such as calcium disodium ethylenediaminetetraacetate (EDTA), 2,3-dimercaptopropanol (BAL), or D-penicillamine (D-PA) have been widely used for the past 4 decades as antidotes for the treatment of acute and chronic metal poisoning. In recent years, meso-2,3-dimercaptosuccinic acid (DMSA), sodium 2,3-dimercapto-1-propanesulfonate (DMPS) and sodium 4,5-dihydroxybenzene-1,3-disulfonate (Tiron) have also shown to be effective to prevent against toxicity induced by a number of heavy metals. The purpose of the present article was to review the protective activity of various chelating agents against the embryotoxic and teratogenic effects of well-known developmental toxicants (arsenic, cadmium, lead, mercury, uranium, and vanadium). DMSA and DMPS were found to be effective in alleviating arsenate- and arsenite-induced teratogenesis, whereas BAL afforded only some protection against arsenic-induced embryo/fetal toxicity. Also, DMSA, DMPS, and Tiopronin were effective in ameliorating methyl mercury-induced developmental toxicity. Although the embryotoxic and teratogenic effects of vanadate were significantly reduced by Tiron, no significant amelioration of uranium-induced embryotoxicity was observed after treatment with this chelator. PMID:7795320

  2. Effectiveness of chelation therapy with time after acute uranium intoxication

    SciTech Connect

    Domingo, J.L.; Ortega, A.; Llobet, J.M.; Corbella, J. )

    1990-01-01

    The effect of increasing the time interval between acute uranium exposure and chelation therapy was studied in male Swiss mice. Gallic acid, 4,5-dihydroxy-1,3- benzenedisulfonic acid (Tiron), diethylenetriaminepentaacetic acid (DTPA), and 5-aminosalicylic acid (5-AS) were administered ip at 0, 0.25, 1, 4, and 24 hr after sc injection of 10 mg/kg of uranyl acetate dihydrate. Chelating agents were given at doses equal to one-fourth of their respective LD50 values. Daily elimination of uranium into urine and feces was determined for 4 days after which time the mice were killed, and the concentration of uranium was measured in kidney, spleen, and bone. The excretion of uranium was especially rapid in the first 24 hr. Treatment with Tiron or gallic acid at 0, 0.25, or 1 hr after uranium exposure significantly increased the total excretion of the metal. In kidney and bone, only administration of Tiron at 0, 0.25, or 1 hr after uranium injection, or gallic acid at 1 hr after uranium exposure significantly reduced tissue uranium concentrations. Treatment at later times (4 to 24 hr) did not increase the total excretion of the metal and did not decrease the tissue uranium concentrations 4 days after uranyl acetate administration. The results show that the length of time before initiating chelation therapy for acute uranium intoxication greatly influences the effectiveness of this therapy.

  3. Increased inorganic mercury in spinal motor neurons following chelating agents.

    PubMed

    Ewan, K B; Pamphlett, R

    1996-01-01

    Heavy metal toxicity has been implicated in the pathogenesis of motor neuron diseases. In an attempt to assess the efficacy of chelating agents to remove mercury from motor neurons, we quantitated the effect of the chelating agents meso-2,3-dimercaptosuccinic acid (DMSA) and 2,3- dimercaptopropane -1-sulphonate (DMPS) on the burden of inorganic mercury in mouse spinal motor neurons. Mice were injected intraperitoneally with 1.0 mg HgCl2/kg body weight and one week later with either 4,400 mg/kg DMPS, 3,600 mg/kg DMSA or 5% NaHCO3 (control) over 4 weeks. Mercury deposits in motor neurons of 50 micron frozen sections of lumbar spinal cord were visualised with an autometallographic technique. Optical sections of silver-enhanced deposits were acquired using a confocal microscope in reflective mode and the volume of the deposits within the perikaryon was estimated. Mercury deposits occupied significantly more volume in motor neurons after both DMPS (7.4%, SD +/- 0.7%) and DMSA (8.0% +/- SD 0.7%) treatment than in controls (4.3%, SD +/- 1.7%). The higher levels of neuronal inorganic mercury may be due to increased entry of mercury into motor axons across the neuromuscular junction as a result of chelator-induced elevated circulating mercury. PMID:8856730

  4. Mercury removal in utility wet scrubber using a chelating agent

    SciTech Connect

    Amrhein, Gerald T.

    2001-01-01

    A method for capturing and reducing the mercury content of an industrial flue gas such as that produced in the combustion of a fossil fuel or solid waste adds a chelating agent, such as ethylenediaminetetraacetic acid (EDTA) or other similar compounds like HEDTA, DTPA and/or NTA, to the flue gas being scrubbed in a wet scrubber used in the industrial process. The chelating agent prevents the reduction of oxidized mercury to elemental mercury, thereby increasing the mercury removal efficiency of the wet scrubber. Exemplary tests on inlet and outlet mercury concentration in an industrial flue gas were performed without and with EDTA addition. Without EDTA, mercury removal totaled 42%. With EDTA, mercury removal increased to 71%. The invention may be readily adapted to known wet scrubber systems and it specifically provides for the removal of unwanted mercury both by supplying S.sup.2- ions to convert Hg.sup.2+ ions into mercuric sulfide (HgS) and by supplying a chelating agent to sequester other ions, including but not limited to Fe.sup.2+ ions, which could otherwise induce the unwanted reduction of Hg.sup.2+ to the form, Hg.sup.0.

  5. TREATMENT OF HEXAVALENT CHROMIUM IN CHROMITE ORE PROCESSING SOLID WASTE USING A MIXED REDUCTANT SOLUTION OF FERROUS SULFATE AND SODIUM DITHIONITE

    EPA Science Inventory

    We developed a method for disseminating ferrous iron in the subsurface to enhance chemical reduction of hexavalent chromium (Cr(VI)) in a chromite ore processing solid waste derived from the production of ferrochrome alloy. The method utilizes ferrous sulfate (FeSO4) in combinati...

  6. FERROUS METALS RECOVERY AT RECOVERY 1, NEW ORLEANS: PERFORMANCE OF THE MODIFIED SYSTEM. TEST NO. 4.05 AND TEST NO. 4.09, RECOVERY 1, NEW ORLEANS

    EPA Science Inventory

    This report documents two series of samplings and the monitoring of enery consumption and shredder hammer wear of the upgraded ferrous recovery system that produces a light ferrous product from the processing of municipal refuse at the New Orleans resource recovery project. A ser...

  7. Tests of stability on waste produced in pilot plant testing using ferrous{center_dot}EDTA and magnesium-enhanced lime for combined SO{sub 2}/NO{sub x} removal

    SciTech Connect

    Mendelsohn, M.H.; Livengood, C.D.

    1994-03-01

    A pilot-plant-scale study of combined sulfur dioxide/nitrogen oxides (SO{sub 2}/NO{sub x}) removal has been performed by the Dravo Lime Company at the Cincinnati Gas and Electric Company`s Miami Fort Station in North Bend, Ohio. This study used Dravo`s patented Thiosorbic{reg_sign} lime process, utilizing a magnesium-enhanced lime, along with Argonne National Laboratory`s (ANL`s) patented ARGONOX metal-chelate additive, ferrous{center_dot}ethylenediaminetetraacetic acid (Fe{center_dot}EDTA). For approximately nine months, scrubbing tests were carried out, and waste samples were collected. Waste testing at ANL involved two types of long-term chemical stability experiments. In one experiment, the gas-phase composition above several different samples was studied by mass spectrometry over a period of about 22 months. Significant changes were noted for oxygen (O{sub 2}), carbon dioxide (CO{sub 2}), and hydrogen sulfide (H{sub 2}S) gases. The other experiment involved solid-phase leaching using the Toxicity Characteristic Leaching Procedure (TCLP). Samples were stored for up to 14 months before leaching. Then each leachate was tested for total Kjeldahl nitrogen and for some nitrogen-containing species. Total leachable nitrogen was found to stabilize after about the first seven months of storage.

  8. Chelating compounds as potential flash rust inhibitors and melamine & aziridine cure of acrylic colloidal unimolecular polymers (CUPs)

    NASA Astrophysics Data System (ADS)

    Mistry, Jigar Kishorkumar

    Waterborne coatings on ferrous substrates usually show flash rusting which decreases the adhesion of the coating and the corrosion products can form a stain. Chelating compounds were investigated as potential flash rust inhibitors. Compounds being evaluated include amine alcohols, diamines and sulfur containing amines. A new corrosion inhibitor 2,5-bis(thioaceticacid)-1,3,4-thiadiazole (H2ADTZ) was synthesized and its performance characteristics were evaluated. It was noted that the observed structure of 1,3,4-thiadiazolidine-2,5-dithione (also known as 2,5-dimercapto-1,3,4-thiadiazole (DMTD or DMcT)) has been previously reported in three different tautomeric forms including -dithiol and -dithione. The relative stability of each form as well as the synthesis and characterization of the structures of mono- and dialkylated forms of 5-mercapto-1,3,4-thiadiazole-2(3H)-thione (MTT) were examined. The methods of X-ray crystallography, NMR spectroscopy and ab-initio electronic structure calculations were combined to understand the reactivity and structure of each compound. Polymers were synthesized with a 1:7 or 1:8 ratio of acrylic acid to acrylate monomers to produce an acid rich resin. The polymers were reduced and solvent stripped to produce Colloidal Unimolecular Polymers (CUPs). These particles are typically 3-9 nanometers in diameter depending upon the molecular weight. They were then formulated into a clear coating with either a melamine (bake) or an aziridine (ambient cure) and then cured. The melamine system was solvent free, a near zero VOC and the aziridine system was very low to near zero VOC. The coatings were evaluated for their MEK resistance, adhesion, hardness, gloss, flexibility, wet adhesion, abrasion and impact resistance properties.

  9. A randomised double-blind study comparing sodium feredetate with ferrous fumarate in anaemia in pregnancy.

    PubMed

    Sarkate, Pankaj; Patil, Amrapali; Parulekar, Shashank; Rege, N N; Samant, B D; Lokhande, Jaisen; Gupta, Ashwaria; Kulkarni, Kamlakar

    2007-05-01

    Iron deficiency anaemia is a major health problem in India especially in women of reproductive age group. The World Health Organisation recommends that the haemoglobin concentration should not fall below 11.0 g/dl at any time during pregnancy. The aim of study was to compare the efficacy and safety of two doses of sodium feredetate with ferrous fumarate in improving haemoglobin profile in pregnant anaemic women. Pregnant women with gestation period between 12 and 26 weeks having serum haemoglobin < 10 g/dl, serum ferritin levels less than 12 microg/l were included in the study. Patients were divided into 3 groups and drugs administered accordingly. A total of 48 patients were available for analysis which included 37 patients who had completed all the visits up to 75 days follow-up and 11 patients who were treatment failures. In group A combination of sodium feredetate (containing 33 mg of elemental iron) along with vitamin B12 (15 microg) and folic acid (1.5 mg) was administered twice a day. In group B combination of sodium feredetate (containing 66 mg of elemental iron) along with vitamin B12 (15 microg) and folic acid (1.5 mg) was administered twice a day. In group C combination of ferrous fumarate (containing 100 mg of elemental iron) along with vitamin B12 (15 microg) and folic acid (1.5 mg) was administered twice a day. Patients were evaluated for Hb, RBC count, MCV, MCH and MCHC at day 0, 30, 45, 60 and 75. Serum ferritin, serum iron, TIBC and transferrin saturation were assessed at recruitment and end study. Mean rise of haemoglobin at the completion of study, over that of basal values was 1.79 g/dl (0.71 to 2.87, 95% CI, p < 0.05) in group A, 1.84 g/dl (0.82 to 2.86, 95% CI, p < 0.05) in group B and 1.63 g/dl (0.38 to 2.88, 95% CI, p < 0.05) in group C. Safety assessment was done by doing liver and kidney function test at the time of recruitment and end study. Low doses of sodium feredetate (33 mg and 66 mg of elemental iron given twice daily) produce comparable results as higher dose of ferrous fumarate (100 mg elemental iron given twice daily). As there were no adverse effects reported with sodium feredetate, it can be concluded from this study that this new formulation appears to be effective in improving haemoglobin profile in pregnant anaemic women and is tolerated well. PMID:17915799

  10. Studies on electronic effects in O-, N- and S-chelated ruthenium olefin-metathesis catalysts.

    PubMed

    Tzur, Eyal; Szadkowska, Anna; Ben-Asuly, Amos; Makal, Anna; Goldberg, Israel; Wo?niak, Krzysztof; Grela, Karol; Lemcoff, N Gabriel

    2010-08-01

    A short overview on the structural design of the Hoveyda-Grubbs-type ruthenium initiators chelated through oxygen, nitrogen or sulfur atoms is presented. Our aim was to compare and contrast O-, N- and S-chelated ruthenium complexes to better understand the impact of electron-withdrawing and -donating substituents on the geometry and activity of the ruthenium complexes and to gain further insight into the trans-cis isomerisation process of the S-chelated complexes. To evaluate the different effects of chelating heteroatoms and to probe electronic effects on sulfur- and nitrogen-chelated latent catalysts, we synthesised a series of novel complexes. These catalysts were compared against two well-known oxygen-chelated initiators and a sulfoxide-chelated complex. The structures of the new complexes have been determined by single-crystal X-ray diffraction and analysed to search for correlations between the structural features and activity. The replacement of the oxygen-chelating atom by a sulfur or nitrogen atom resulted in catalysts that were inert at room temperature for typical ring-closing metathesis (RCM) and cross-metathesis reactions and showed catalytic activity only at higher temperatures. Furthermore, one nitrogen-chelated initiator demonstrated thermo-switchable behaviour in RCM reactions, similar to its sulfur-chelated counterparts. PMID:20564287

  11. Performance of Nonmigratory Iron Chelating Active Packaging Materials in Viscous Model Food Systems.

    PubMed

    Roman, Maxine J; Decker, Eric A; Goddard, Julie M

    2015-09-01

    Many packaged food products undergo quality deterioration due to iron promoted oxidative reactions. Recently, we have developed a nonmigratory iron chelating active packaging material that represents a novel approach to inhibit oxidation of foods while addressing consumer demands for "clean? labels. A challenge to the field of nonmigratory active packaging is ensuring that surface-immobilized active agents retain activity in a true food system despite diffusional limitations. Yet, the relationship between food viscosity and nonmigratory active packaging activity retention has never been characterized. The objective of this study was to investigate the influence of food viscosity on iron chelation by a nonmigratory iron chelating active packaging material. Methyl cellulose was added to aqueous buffered iron solutions to yield model systems with viscosities ranging from ?1 to ?10(5) mPas, representing viscosities ranging from beverage to mayonnaise. Iron chelation was quantified by material-bound iron content using colorimetry and inductively coupled plasma-optical emission spectrometry (ICP-OES). Maximum iron chelation was reached in solutions up to viscosity ?10(2) mPas. In more viscous solutions (up to ?10(4) mPas), there was a significant decrease in iron chelating capacity (P < 0.05). However, materials still retained at least 76% iron chelating capacity. Additionally, the influence of different food hydrocolloids on the performance of nonmigratory iron chelating active packaging was characterized. Methyl cellulose and carrageenan did not compete with the material for specific iron chelation (P > 0.05). Materials retained 32% to 45% chelating capacity when in contact with competitively chelating hydrocolloids guar gum, locust bean gum, and xanthan gum. This work demonstrates the potential application of nonmigratory iron chelating active packaging in liquid and semi-liquid foodsto allow for the removal of synthetic chelators, while maintaining food quality. PMID:26220302

  12. INJECTION OF A FERROUS SULFATE/SODIUM DITHIONITE REDUCTANT FOR IN-SITU TREATMENT OF HEXAVALENT CHROMIUM

    EPA Science Inventory

    An in situ pilot study was conducted to evaluate the performance of a ferrous iron-based reductant solution in treating hexavalent chromium within a saturated zone source area at a former industrial site in Charleston, South Carolina (USA). The hexavalent source area, consisting...

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

    EPA Science Inventory

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

  14. Use of a Ferrous Sulfate - Sodium Dithionite Blend to Treat a Dissolved Phase Cr(VI) Plume

    EPA Science Inventory

    A field study was conducted to evaluate the use of a combination of sodium dithionite and ferrous sulfate in creating an in situ redox zone for treatment of a dissolved phase Cr(VI) plume at a former industrial site. The reductant blend was injected into the path of a dissolved ...

  15. IMPROVEMENT OF MAGNETICALLY SEPARATED FERROUS CONCENTRATE BY SHREDDING: A PERFORMANCE TEST. TEST NO. 4.07, RECOVERY 1, NEW ORLEANS

    EPA Science Inventory

    This report describes a series of test runs in which ferrous product magnetically recovered from municipal waste was further shredded in a small (50 hp) hammermill to free attached or entrapped contaminant. A belt magnet was then used to separate metal from the liberated contamin...

  16. Tribological Behavior of Ferrous-Based APS Coatings Under Dry Sliding Conditions

    NASA Astrophysics Data System (ADS)

    Vencl, Aleksandar

    2015-04-01

    The use of Al-alloys for engine blocks production, instead of e.g., gray cast iron, results with weight savings and lower fuel consumption and therefore, reduces pollution. Possible solution for overcoming poor tribological properties of Al-alloys is the application of thermal spray coatings. In this paper, the tribological properties of two ferrous-based coatings were analyzed and compared with gray cast iron as a standard material for engine blocks. The process used for coating deposition on an Al-Si alloy substrate was atmospheric plasma spraying. In order to investigate the tribological behavior of these coatings under dominant adhesive and abrasive wear regime, two tests were applied with different test equipments and conditions. Both tribological tests showed that, for the investigated conditions, both coatings had improved wear resistance and lower coefficient of friction compared with gray cast iron.

  17. Reactivity of an All-Ferrous Iron-Nitrogen Heterocubane under Reductive and Oxidative Conditions.

    PubMed

    Lichtenberg, Crispin; Prokopchuk, Demyan E; Adelhardt, Mario; Viciu, Liliana; Meyer, Karsten; Grtzmacher, Hansjrg

    2015-10-26

    The reactivity of the all-ferrous FeN heterocubane [Fe4 (Ntrop)4 ] (1) with i)?Brnsted acids, ii)??-donors, iii)??-donors/?-acceptors, and iv)?one-electron oxidants has been investigated (trop = 5H-dibenzo[a,d]cyclo-hepten-5-yl). 1 showed self-re-assembling after reactions with i) and proved surprisingly inert in reactions with ii) and iii), with the exception of CO. Reductive and oxidative cluster degradation was observed in reactions with CO and TEMPO, respectively. These reactions yielded new cluster compounds, namely a trinuclear bis(?3 -imido) 48 electron complex in the former case and a tetranuclear all ferric ?-oxo-?-imido species in the latter case. Characterization techniques include NMR and in situ IR spectroscopy, single crystal X-ray analysis, Mssbauer spectroscopy, cyclic voltammetry, magnetic susceptibility measurements, and DFT calculations. PMID:26374167

  18. Iron oxide and hydroxide precipitation from ferrous solutions and its relevance to Martian surface mineralogy

    NASA Technical Reports Server (NTRS)

    Posey-Dowty, J.; Moskowitz, B.; Crerar, D.; Hargraves, R.; Tanenbaum, L.

    1986-01-01

    Experiments were performed to examine if the ubiquitousness of a weak magnetic component in all Martian surface fines tested with the Viking Landers can be attributed to ferric iron precipitation in aqueous solution under oxidizing conditions at neutral pH. Ferrous solutions were mixed in deionized water and various minerals were added to separate liquid samples. The iron-bearing additives included hematite, goethite, magnetite, maghemite, lepidocrocite and potassium bromide blank at varying concentrations. IR spectroscopic scans were made to identify any precipitates resulting from bubbling oxygen throughout the solutions; the magnetic properties of the precipitates were also examined. The data indicated that the lepidocrocite may have been preferentially precipitated, then aged to maghemite. The process would account for the presumed thin residue of maghemite on the present Martian surface, long after abundant liquid water on the Martian surface vanished.

  19. Iron oxide and hydroxide precipitation from ferrous solutions and its relevance to Martian surface mineralogy

    SciTech Connect

    Posey-Dowty, J.; Moskowitz, B.; Crerar, D.; Hargraves, R.; Tanenbaum, L.

    1986-04-01

    Experiments were performed to examine if the ubiquitousness of a weak magnetic component in all Martian surface fines tested with the Viking Landers can be attributed to ferric iron precipitation in aqueous solution under oxidizing conditions at neutral pH. Ferrous solutions were mixed in deionized water and various minerals were added to separate liquid samples. The iron-bearing additives included hematite, goethite, magnetite, maghemite, lepidocrocite and potassium bromide blank at varying concentrations. IR spectroscopic scans were made to identify any precipitates resulting from bubbling oxygen throughout the solutions; the magnetic properties of the precipitates were also examined. The data indicated that the lepidocrocite may have been preferentially precipitated, then aged to maghemite. The process would account for the presumed thin residue of maghemite on the present Martian surface, long after abundant liquid water on the Martian surface vanished. 40 references.

  20. Mars: Compositional variability of ferric/ferrous minerals and polar volatiles from groundbased imaging spectroscopy

    NASA Technical Reports Server (NTRS)

    Bell, James F., III

    1992-01-01

    In an attempt to further constrain the ferric and ferrous mineralogy of Mars, Bell et al. (1989; 1990) obtained high resolution imaging spectroscopic data of much of the Martian surface in the visible and near-infrared (0.4-1.1 micron) during the 1988 opposition. Preliminary analysis of these data showed further evidence of crystalline hematite absorption features at 0.8-0.9 microns and 0.6-0.7 microns. Additionally, the 0.6-0.7 micron Fe(III) band was shown to vary across the surface, with a substantial correlation with albedo in the region studied. Calibration of this 1988 data set (along with a similar data set obtained during the 1990 opposition) has been ongoing, and some of the most recent results of the analysis of these data using linear spectral mixture modeling are reported.

  1. Ferrous iron and α-ketoglutarate-dependent dioxygenases in the biosynthesis of microbial natural products.

    PubMed

    Wu, Long-Fei; Meng, Song; Tang, Gong-Li

    2016-05-01

    Apart from its vital role as the terminal electron acceptor in oxidative phosphorylation in nature, dioxygen also serves as a universal agent which diversifies natural products by oxidative transformations. Ferrous iron and α-ketoglutarate (αKG)-dependent dioxygenases (αKGDs) are versatile enzymes that use dioxygen as an oxidant to catalyse various reactions via CH bond activation, including hydroxylation, dealkylation, desaturation, epoxidation, epimerisation, halogenation, cyclisation, peroxide formation, and ring expansion/contraction reactions. This review updates the reported αKGDs that catalyse reactions related to microbial natural product biosynthesis in the past 10years. We hope that the versatility of αKGDs shown here can serve as an inspiration for future engineering and catalyst design, which could provide alternative methods to meet the on-going demand for fine chemicals and pharmaceutics. PMID:26845569

  2. Evaluation of a ferrous benzoic xylenol orange transparent PVA cryogel radiochromic dosimeter.

    PubMed

    Eyadeh, Molham M; Farrell, Thomas J; Diamond, Kevin R

    2014-04-01

    A stable cryogel dosimeter was prepared using ferrous benzoic xylenol orange (FBX) in a transparent poly-(vinyl alcohol) (PVA) cryogel matrix. Dose response was evaluated for different numbers of freeze-thaw cycles (FTCs), different concentrations of PVA, and ratios of water/dimethyl sulfoxide. Linear relationships between dose and absorbance were obtained in the range of 0-1000 cGy for all formulations. Increasing the concentration of PVA and number of FTCs resulted in increased absorbance and sensitivity. The effects of energy and dose rate were also evaluated. No significant dose rate dependence was observed over the range 1.05 to 6.33 Gy min(-1). No energy response was observed over photon energies of 6, 10, and 18 MV. PMID:24619200

  3. Three-dimensional determination of absorbed dose by spectrophotometric analysis of ferrous-sulphate agarose gel

    NASA Astrophysics Data System (ADS)

    Gambarini, G.; Gomarasca, G.; Marchesini, R.; Pecci, A.; Pirola, L.; Tomatis, S.

    1999-02-01

    We describe a technique to obtain three-dimensional (3-D) imaging of an absorbed dose by optical transmittance measurements of phantoms composed by agarose gel in which a ferrous sulphate and xylenol orange solution are incorporated. The analysis of gel samples is performed by acquiring transmittance images with a system based on a CCD camera provided with an interference filter matching the optical absorption peak of interest. The proposed technique for 3-D measurements of an absorbed dose is based on the imaging of phantoms composed of sets of properly piled up gel slices. The slice thickness was optimized in order to obtain a good image contrast as well as a good in-depth spatial resolution. To test the technique, a phantom has been irradiated with a collimated γ-beam and then analysed. Proper software was adapted in order to visualise the images of all slices and to attain the 2-D profiles of the dose absorbed by each slice.

  4. Evaluation of a ferrous benzoic xylenol orange transparent PVA cryogel radiochromic dosimeter

    NASA Astrophysics Data System (ADS)

    Eyadeh, Molham M.; Farrell, Thomas J.; Diamond, Kevin R.

    2014-04-01

    A stable cryogel dosimeter was prepared using ferrous benzoic xylenol orange (FBX) in a transparent poly-(vinyl alcohol) (PVA) cryogel matrix. Dose response was evaluated for different numbers of freeze-thaw cycles (FTCs), different concentrations of PVA, and ratios of water/dimethyl sulfoxide. Linear relationships between dose and absorbance were obtained in the range of 0-1000 cGy for all formulations. Increasing the concentration of PVA and number of FTCs resulted in increased absorbance and sensitivity. The effects of energy and dose rate were also evaluated. No significant dose rate dependence was observed over the range 1.05 to 6.33 Gy min-1. No energy response was observed over photon energies of 6, 10, and 18 MV.

  5. Direct recycling of municipal ferrous wastes for local foundry application. Final technical report

    SciTech Connect

    Not Available

    1981-01-09

    This project investigated the concept of direct recycling as an appropriate technology (AT) approach to improving resource recovery from wastes in Region III. Direct recycling is the process of bringing waste materials directly to reprocessing facilities with few or no intermediate processing steps. Municipal Ferrous Waste (MFW) was the waste material involved. The Region III states were surveyed for (a) municipal recycling systems incorporating MFW separation and (b) grey iron foundries where MFW could be utilized. Contacts and visits were made with foundry and recycling group personnel. A handbook titled Tin Cans and Trash Recovery was prepared for distribution to interested persons in Region III. This handbook delineates the direct recycling method for MFW, describes recycling potential for areas of different populations in the Region, and lists foundries, recycling groups, and resource persons for the Region. It was distributed widely in Region III and elsewhere.

  6. Fast start-up of Anammox process with appropriate ferrous iron concentration.

    PubMed

    Bi, Zhen; Qiao, Sen; Zhou, Jiti; Tang, Xin; Zhang, Jie

    2014-10-01

    In this study, three upflow column reactors were compared for anaerobic ammonium oxidation (Anammox) process start-up time with different ferrous iron concentration in feeding. Continuous experiments indicated that the start-up time of Anammox process could be shortened from 70 to 58d in R2 (0.06mM Fe(2+)) and 50d in R3 (0.09mM Fe(2+)). The Anammox activity appeared after 16days operation in R3. Quantitative PCR (q-PCR) analysis demonstrated a significant increase in quantity of Anammox bacteria in R3 compared with the other two reactors during entire operation. At the Fe(II) concentration of 0.09mM, the heme c levels inside Anammox cell and hydrazine dehydrogenase (HDH) activity increased dramatically, which could be the trigger of fast Anammox start-up. PMID:25164343

  7. Hydrogen peroxide-independent generation of superoxide catalyzed by soybean peroxidase in response to ferrous ion.

    PubMed

    Kimura, Makoto; Kawano, Tomonori

    2015-11-01

    It is well documented that extracellular alkalization occurs in plants under the challenges by pathogenic microbes. This may eventually induce the pH-dependent extracellular peroxidase-mediated oxidative burst at the site of microbial challenges. By employing the purified proteins of horseradish peroxidase as a model, we have recently proposed a likely role for free Fe(2+) in reduction of ferric enzyme of plant peroxidases into ferrous intermediate and oxygen-bound form of enzyme known as Compound III which may eventually releases superoxide anion radical (O2(-)), especially under alkaline condition, possibly contributing to the plant defense mechanism. In the present study, we employed the purified protein of soybean peroxidase (SBP) as an additional model, and examined the changes in the redox status of enzyme accompanying the generation of O2(-) in response to Fe(2+) under alkaline condition. PMID:26417938

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

    PubMed Central

    Kosman, Daniel J.

    2012-01-01

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

  9. Kinetics of triscarbonato uranyl reduction by aqueous ferrous iron: a theoretical study.

    PubMed

    Wander, Matthew C F; Kerisit, Sebastien; Rosso, Kevin M; Schoonen, Martin A A

    2006-08-10

    Uranium is a pollutant whose mobility is strongly dependent on its oxidation state. While U(VI) in the form of the uranyl cation is readily reduced by a range of natural reductants, by contrast complexation of uranyl by carbonate greatly reduces its reduction potential and imposes increased electron transfer (ET) distances. Very little is known about the elementary processes involved in uranium reduction from U(VI) to U(V) to U(IV) in general. In this study, we examine the theoretical kinetics of ET from ferrous iron to triscarbonato uranyl in aqueous solution. A combination of molecular dynamics (MD) simulations and density functional theory (DFT) electronic structure calculations is employed to compute the parameters that enter into Marcus' ET model, including the thermodynamic driving forces, reorganization energies, and electronic coupling matrix elements. MD simulations predict that two ferrous iron atoms will bind in an inner-sphere fashion to the three-membered carbonate ring of triscarbonato uranyl, forming the charge-neutral ternary Fe(2)UO(2)(CO(3))(3)(H(2)O)(8) complex. Through a sequential proton-coupled electron-transfer mechanism (PCET), the first ET step converting U(VI) to U(V) is predicted by DFT to occur with an electronic barrier that corresponds to a rate on the order of approximately 1 s(-1). The second ET step converting U(V) to U(IV) is predicted to be significantly endergonic. Therefore, U(V) is a stabilized end product in this ET system, in agreement with experiment. PMID:16884201

  10. Structural analysis of metastable pseudobrookite ferrous titanium oxides with neutron diffraction and Mossbauer spectroscopy

    NASA Astrophysics Data System (ADS)

    Teller, Raymond G.; Antonio, Mark R.; Grau, Alphonso E.; Gueguin, Michel; Kostiner, Edward

    1990-10-01

    Four synthetic iron titanium oxides with the pseudobrookite ( AB2O 5, Cmcm, Z = 4) structure have been prepared and characterized by neutron diffraction and zero-field, natural abundance 57Fe Mossbauer effect spectroscopy (MES). The combination of the element specificity of MES with the different neutron scattering lengths of Ti and Fe (-0.33 and 0.95 10 -12 cm, respectively) offers a unique opportunity to distinguish between cation distributions on the two (" A" and " B") sites. Two of the samples have been prepared in low temperature experiments (quenched from 1200C) and have the stoichiometry FeTi 2O 5, and Fe .6Mg .6Ti 1.8O 5. The third and fourth samples are commercial iron titanium oxides prepared by the reduction of ilmenite ore with carbon above 1700C. The stoichiometries of these samples are Mn 0.05Fe 0.33Ti 2.52O 5 and Fe .33Mg .31Ti 2.36O 5. Results from these experiments indicate that for each of these samples the B site is predominantly (>65%) occupied by Ti, while the A site contains a mixture of Ti, Fe, and/or Mg. However, only at higher temperatures (>1700C) is the B site devoid of ferrous cations. These results suggest that an "ordered" model for ferrous titanium-rich oxides of the pseudobrookite structure (100% Ti occupancy of the B site) is descriptive only at elevated temperatures, and that at lower temperatures a "disordered" model (partial iron occupation of the B site) is a more accurate representation of the structure. Because of this difference, it may be possible to predict the thermal history of naturally occurring samples based on cation distributions.

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

    PubMed

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

    2016-02-01

    In this study, the removal of ibuprofen (IBP), a pharmaceutical compound, from aqueous media by Money plant (Epipremnum aureum) was investigated. The effect of ferrous iron (Fe(2+)) on enhancing the IBP removal rate was also analyzed. The first-order removal rate constants showed higher values for lower IBP initial concentrations in the range of 0.20-0.28 d(-1) for an initial concentration of 125?gL(-1) to 0.03-0.13 d(-1) for an initial concentration of 1000?gL(-1). Introducing ferrous iron to the aqueous media enhanced the first-order removal rate constant up to 6.5 times in a 3d time period. Along with the removal of IBP from the media, the endogenous concentration of H2O2 also decreased presumably by the production of hydroxyl radical (OH). Reduction in the endogenous H2O2 concentration was recorded to be 38% and 98% in the absence and presence of Fe(2+) respectively in the first day and the H2O2 level remained considerably low until day 7 which then gradually increased slightly. Simultaneous reduction of IBP and endogenous H2O2 concentration could be due to the reaction of IBP with OH and presumably OH production itself accelerated via Fenton reaction. In addition, presence of sodium bicarbonate (NaHCO3) as OH scavenger in the system showed reduction of first-order removal rate constant from 1.30 d(-1) to 0.07 d(-1) which could be a possible evidence of biological advanced oxidation process which is believed to play an important role in phytoremediation. PMID:26347930

  12. Optical Imaging of Radiation Dose Distributions in a Ferrous-Gelatin Orange Gel Dosimeter.

    NASA Astrophysics Data System (ADS)

    Fried, Richard Marc

    A new tissue-equivalent radiation dosimeter was developed and studied. The dosimeter consists of a ferrous -xylenol orange solution suspended in a gelatin matrix. Ferric ions produced from irradiation react with the xylenol orange dye to form a complex which absorbs light maximally at 585 nm, in the visible band. The optical density at this wavelength increases in proportion to the absorbed dose over a limited dose range. The dosimeter's gelatin component serves to solidify the chemical system so that an irradiated dosimeter yields a stable three-dimensional image of its dose distribution. The dosimeter is transparent to most other visible wavelengths so that the image of the dose distribution is clearly visible to the naked eye. Experiments were conducted in order to optimize the sensitivity of the chemical system and determine the conditions which produce a linear dose response for doses up to 6 Gray. A computed-tomography system was developed in order to quantify the dose-distribution images recorded by the dosimeter. The accuracy of the tomographic-reconstruction process was to be determined by comparing the resulting data to that obtained by standard dosimetry techniques. It was found that dosimeter sensitivity is gained with increasing ferrous and/or gelatin concentration and decreasing xylenol orange concentration. It was also determined that a dose range which provides a linear response can be extended by increasing the xylenol orange concentration and/or decreasing the dosimeter's sensitivity. An optimal chemical formulation that achieves a balance among sensitivity, linearity, and dosimeter stability was defined. In preliminary tests involving a homogeneous-dose simulation, the tomography code was tested and determined to be in error as it produced an inaccurate rendering of the dosimeter volume. Reasons for this error are discussed and suggestions for an improved optical-tomography system are made.

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

    USGS Publications Warehouse

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

    2013-01-01

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

  14. Assessment of ferrous chloride and Portland cement for the remediation of chromite ore processing residue.

    PubMed

    Jagupilla, Santhi C; Wazne, Mahmoud; Moon, Deok Hyun

    2015-10-01

    Chromite Ore Processing Residue (COPR) is an industrial waste containing up to 7% chromium (Cr) including up to 5% hexavalent chromium [Cr(VI)]. The remediation of COPR has been challenging due to the slow release of Cr(VI) from a clinker like material and thereby the incomplete detoxification of Cr(VI) by chemical reagents. The use of sulfur based reagents such as ferrous sulfate and calcium polysulfide to detoxify Cr(VI) has exasperated the swell potential of COPR upon treatment. This study investigated the use of ferrous chloride alone and in combination with Portland cement to address the detoxification of Cr(VI) in COPR and the potential swell of COPR. Chromium regulatory tests, X-ray powder diffraction (XRPD) analyses and X-ray absorption near edge structure (XANES) analyses were used to assess the treatment results. The treatment results indicated that Cr(VI) concentrations for the acid pretreated micronized COPR as measured by XANES analyses were below the New Jersey Department of Environmental Protection (NJDEP) standard of 20 mg kg(-1). The Toxicity characteristic leaching procedure (TCLP) Cr concentrations for all acid pretreated samples also were reduced below the TCLP regulatory limit of 5 mg L(-1). Moreover, the TCLP Cr concentration for the acid pretreated COPR with particle size ⩽0.010 mm were less than the universal treatment standard (UTS) of 0.6 mg L(-1). The treatment appears to have destabilized all COPR potential swell causing minerals. The unconfined compressive strength (UCS) for the treated samples increased significantly upon treatment with Portland cement. PMID:25966327

  15. Rates of cuticular penetration of chelated Fe(III): role of humidity, concentration, adjuvants, temperature, and type of chelate.

    PubMed

    Schnherr, Jrg; Fernndez, Victoria; Schreiber, Lukas

    2005-06-01

    Time courses of cuticular penetration of FeCl3 and Fe(III) complexes of citric acid, EDTA, EDDHA (Sequestrene 138Fe), imidodisuccinic acid (IDHA), and ligninsulfonic acid (Natrel) were studied using astomatous cuticular membranes (CMs) isolated from Populus x canescens leaves. At 100% relative humidity, the Fe(III) chelates disappeared exponentially with time from the surface of the CMs; that is, penetration was a first-order process that can be described using rate constants or half-times of penetration (t(1/2)). Half-times ranged from 20 to 30 h. At 90% humidity, penetration rates were insignificant with the exception of Natrel, for which t(1/2) amounted to 58 h. Rate constants were independent of temperature (15, 25, and 35 degrees C). Permeability decreased with increasing Fe chelate concentration (IDHA and EDTA). At 100% humidity, half-times measured with FeIDHA were 11 h (2 mmol L(-1)), 17 h (10 mmol L(-1)) and 36 h (20 mmol L(-1)), respectively. In the presence of FeEDTA, penetration of CaCl2 was slowed greatly. Half-times for penetration of CaCl2, which were 1.9 h in the absence of FeEDTA, rose to 3.12 h in the presence of an equimolar concentration of EDTA and 13.3 h when the FeEDTA concentration was doubled. Hence, Fe chelates reduced permeability of CMs to CaCl2 and to the Fe chelates themselves. It is suggested that Fe chelates reduced the size of aqueous pores. This view is supported by the fact that rate constants for calcium salts were about 5 times higher than for Fe chelates with the same molecular weights. Adding Tween 20 (5 g L(-1)) as a humectant did not increase permeability to FeIDHA at 90% humidity and below, while addition of glycine betaine did. Penetration of FeCl3 applied at 5 g L(-1) (pH 1.5) was not a first order process as rate constants decreased rapidly with time. Only 2% of the dose penetrated during the first 2 h and less than that in the subsequent 8 h. Recovery was only 70%. This was attributed to the formation of insoluble Fe hydroxide precipitates on CMs. These results explain why in the past foliar application of Fe compounds had limited success. Inorganic Fe salts are instable and phytotoxic because of low pH, while Fe chelates penetrate slowly and 100% humidity is required for significant penetration rates. Concentrations as low as reasonably possible should be used. These physical facts are expected to apply to stomatous leaf surfaces as well, but absolute rates probably depend on leaf age and plant species. High humidity in stagnant air layers may favor penetration rates across stomatous leaf surfaces when humidity in bulk air is below 100%. PMID:15913315

  16. Ferrous Sulfate Supplementation Causes Significant Gastrointestinal Side-Effects in Adults: A Systematic Review and Meta-Analysis

    PubMed Central

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

    2015-01-01

    Background The tolerability of oral iron supplementation for the treatment of iron deficiency anemia is disputed. Objective Our aim was to quantify the odds of GI side-effects in adults related to current gold standard oral iron therapy, namely ferrous sulfate. Methods Systematic review and meta-analysis of randomized controlled trials (RCTs) evaluating GI side-effects that included ferrous sulfate and a comparator that was either placebo or intravenous (IV) iron. Random effects meta-analysis modelling was undertaken and study heterogeneity was summarised using I2 statistics. Results Forty three trials comprising 6831 adult participants were included. Twenty trials (n = 3168) had a placebo arm and twenty three trials (n = 3663) had an active comparator arm of IV iron. Ferrous sulfate supplementation significantly increased risk of GI side-effects versus placebo with an odds ratio (OR) of 2.32 [95% CI 1.74–3.08, p<0.0001, I2 = 53.6%] and versus IV iron with an OR of 3.05 [95% CI 2.07-4.48, p<0.0001, I2 = 41.6%]. Subgroup analysis in IBD patients showed a similar effect versus IV iron (OR = 3.14, 95% CI 1.34-7.36, p = 0.008, I2 = 0%). Likewise, subgroup analysis of pooled data from 7 RCTs in pregnant women (n = 1028) showed a statistically significant increased risk of GI side-effects for ferrous sulfate although there was marked heterogeneity in the data (OR = 3.33, 95% CI 1.19-9.28, p = 0.02, I2 = 66.1%). Meta-regression did not provide significant evidence of an association between the study OR and the iron dose. Conclusions Our meta-analysis confirms that ferrous sulfate is associated with a significant increase in gastrointestinal-specific side-effects but does not find a relationship with dose. PMID:25700159

  17. NMR study of the interaction of fluorescent 3-hydroxy-4-pyridinone chelators with DMPC liposomes.

    PubMed

    Moniz, Tânia; de Castro, Baltazar; Rangel, Maria; Ivanova, Galya

    2016-02-01

    In the present study we discuss the interaction of two fluorescent 3-hydroxy-4-pyridinone chelators (MRB7 and MRB8) of different lipophilicities with DMPC liposomes based on the analysis of the shifts of the resonance NMR signals and changes in the translational diffusion of both species. The analysis of the variation of the resonance signals of the chelators indicates that both MRB7 and MRB8 strongly interact with the liposomes and that such interaction occurs through both the fluorophore and the chelating moieties of the chelator's framework. Analysis of the variations in the characteristic resonance signals of the lipid provides evidence that MRB7 is able to reach the hydrophobic zone of the bilayer independent of the chelator concentration. The present results corroborate the fact that ethyl substituents in the amino groups of the xanthene ring and the thiourea link are important for the chelator's ability to diffuse across the lipid bilayer. PMID:26812137

  18. EDTA Chelation Therapy to Reduce Cardiovascular Events in Persons with Diabetes.

    PubMed

    Ouyang, Pamela; Gottlieb, Sheldon H; Culotta, Valerie L; Navas-Acien, Ana

    2015-11-01

    The Trial to Assess Chelation Therapy (TACT) was a randomized double-blind placebo-controlled trial enrolling patients age ?50 years with prior myocardial infarction. TACT used a 2 2 factorial design to study ethylene diamine tetraacetic acid (EDTA) chelation and high-dose vitamin supplementation. Chelation provided a modest but significant reduction in cardiovascular endpoints. The benefit was stronger and significant among participants with diabetes but absent in those without diabetes. Mechanisms by which chelation might reduce cardiovascular risk in persons with diabetes include the effects of EDTA chelation on transition and toxic metals. Transition metals, particularly copper and iron, play important roles in oxidative stress pathways. Toxic metals, in particular cadmium and lead, are toxic for the cardiovascular system. This review discusses the epidemiologic evidence and animal and human studies supporting the role of these metals in the development of diabetes and ischemic heart disease and potential ways by which EDTA chelation could confer cardiovascular benefit. PMID:26364188

  19. Synergistic intracellular iron chelation combinations: mechanisms and conditions for optimizing iron mobilization.

    PubMed

    Vlachodimitropoulou Koumoutsea, Evangelia; Garbowski, Maciej; Porter, John

    2015-09-01

    Iron chelators are increasingly combined clinically but the optimal conditions for cellular iron mobilization and mechanisms of interaction are unclear. Speciation plots for iron(III) binding of paired combinations of the licensed iron chelators desferrioxamine (DFO), deferiprone (DFP) and deferasirox (DFX) suggest conditions under which chelators can combine as 'shuttle' and 'sink' molecules but this approach does not consider their relative access and interaction with cellular iron pools. To address this issue, a sensitive ferrozine-based detection system for intracellular iron removal from the human hepatocyte cell line (HuH-7) was developed. Antagonism, synergism or additivity with paired chelator combinations was distinguished using mathematical isobologram analysis over clinically relevant chelator concentrations. All combinations showed synergistic iron mobilization at 8h with clinically achievable concentrations of sink and shuttle chelators. Greatest synergism was achieved by combining DFP with DFX, where about 60% of mobilized iron was attributable to synergistic interaction. These findings predict that the DFX dose required for a half-maximum effect can be reduced by 38-fold when only 1?mol/l DFP is added. Mechanisms for the synergy are suggested by consideration of the iron-chelate speciation plots together with the size, charge and lipid solubilities for each chelator. Hydroxypyridinones with low lipid solubilities but otherwise similar properties to DFP were used to interrogate the mechanistic interactions of chelator pairs. These studies confirm that synergistic cellular iron mobilization requires one chelator to have the physicochemical properties to enter cells, chelate intracellular iron and subsequently donate iron to a second 'sink' chelator. PMID:26033030

  20. Synthesis and antioxidant evaluation of some novel ortho-hydroxypyridine-4-one iron chelators

    PubMed Central

    Mohammadpour, M.; Sadeghi, A.; Fassihi, A.; Saghaei, L.; Movahedian, A.; Rostami, M.

    2012-01-01

    A series of ortho-hydroxypyridine-4-ones were prepared in high yields and evaluated for antioxidant and iron chelating activities. N1-H hydroxypyridinones Va, Vb, and Ve were the best radical scavengers in DPPH free radical scavenging assay. Compound Vb was proved to be the most potent compound in hydrogen peroxide scavenging assay. All of the synthesized compounds had very close chelating ability, compounds containing N1-CH3 hydroxypyridinone ring were stronger chelating agents. PMID:23181095

  1. Chelate-modified polymers for atmospheric gas chromatography

    NASA Technical Reports Server (NTRS)

    Christensen, W. W.; Mayer, L. A.; Woeller, F. H. (Inventor)

    1980-01-01

    Chromatographic materials were developed to serve as the stationary phase of columns used in the separation of atmospheric gases. These materials consist of a crosslinked porous polymer matrix, e.g., a divinylbenzene polymer, into which has been embedded an inorganic complexed ion such as N,N'-ethylene-bis-(acetylacetoniminato)-cobalt (2). Organic nitrogenous bases, such as pyridine, may be incorporated into the chelate polymer complexes to increase their chromatographic utility. With such materials, the process of gas chromatography is greatly simplified, especially in terms of time and quantity of material needed for a gas separation.

  2. Effect of neutralized solid waste generated in lime neutralization on the ferrous ion bio-oxidation process during acid mine drainage treatment.

    PubMed

    Liu, Fenwu; Zhou, Jun; Zhou, Lixiang; Zhang, Shasha; Liu, Lanlan; Wang, Ming

    2015-12-15

    Bio-oxidation of ferrous ions prior to lime neutralization exhibits great potential for acid mine drainage (AMD) treatment, while slow ferrous ion bio-oxidation or total iron precipitation is a bottleneck in this process. In this study, neutralized solid waste (NSW) harvested in an AMD lime neutralization procedure was added as a crystal seed in AMD for iron oxyhydroxysulfate bio-synthesis. The effect of this waste on ferrous ion oxidation efficiency, total iron precipitation efficiency, and iron oxyhydroxysulfate minerals yield during ferrous ion bio-oxidation by Acidithiobacillus ferrooxidans was investigated. Ferrous ion oxidation efficiency was greatly improved by adding NSW. After 72h incubation, total iron precipitation efficiency in treatment with 24g/L of NSW was 1.74-1.03 times higher than in treatment with 0-12g/L of NSW. Compared with the conventional treatment system without added NSW, the iron oxyhydroxysulfate minerals yield was increased by approximately 21.2-80.9% when 3-24g/L of NSW were added. Aside from NSW, jarosite and schwertmannite were the main precipitates during ferrous ion bio-oxidation with NSW addition. NSW can thus serve as the crystal seed for iron oxyhydroxysulfate mineral bio-synthesis in AMD, and improve ferrous ion oxidation and total iron precipitation efficiency significantly. PMID:26150283

  3. Correlation of molecular structure with fluorescence spectra in rare earth chelates. I.

    NASA Technical Reports Server (NTRS)

    Bjorklund, S.; Degnan, J.; Filipescu, N.; Mcavoy, N.

    1968-01-01

    Rare earth chelates fluorescence spectra correlation with molecular structure, analyzing emission spectrum internal Stark splitting of tetramethylammonium tetrakis /dibenzoylmethido/europate microcrystals

  4. Effect of metal chelators on the oxidative stability of model wine.

    PubMed

    Kreitman, Gal Y; Cantu, Annegret; Waterhouse, Andrew L; Elias, Ryan J

    2013-10-01

    Oxidation is a major problem with respect to wine quality, and winemakers have few tools at their disposal to control it. In this study, the effect of exogenous Fe(II) (bipyridine; Ferrozine) and Fe(III) chelators (ethylenediaminetetraacetic acid, EDTA; phytic acid) on nonenzymatic wine oxidation was examined. The ability of these chelators to affect the formation of 1-hydroxyethyl radicals (1-HER) and acetaldehyde was measured using a spin trapping technique with electron paramagnetic resonance (EPR) and by HPLC-PDA, respectively. The chelators were then investigated for their ability to prevent the oxidative loss of an important aroma-active thiol, 3-mercaptohexan-1-ol (3MH). The Fe(II)-specific chelators were more effective than the Fe(III) chelators with respect to 1-HER inhibition during the early stages of oxidation and significantly reduced oxidation markers compared to a control during the study. However, although the addition of Fe(III) chelators was less effective or even showed an initial pro-oxidant activity, the Fe(III) chelators proved to be more effective antioxidants compared to Fe(II) chelators after 8 days of accelerated oxidation. In addition, it is shown for the first time that Fe(II) and Fe(III) chelators can significantly inhibit the oxidative loss of 3MH in model wine. PMID:24001152

  5. Chelating polymeric beads as potential therapeutics for Wilson's disease.

    PubMed

    Mattov, Jana; Pou?kov, Pavla; Ku?ka, Jan; Skodov, Michaela; Vetrk, Miroslav; St?pnek, Petr; Urbnek, Petr; Pet?k, Milo; Nov, Zbyn?k; Hrub, Martin

    2014-10-01

    Wilson's disease is a genetic disorder caused by a malfunction of ATPase 7B that leads to high accumulation of copper in the organism and consequent toxic effects. We propose a gentle therapy to eliminate the excessive copper content with oral administration of insoluble non-resorbable polymer sorbents containing selective chelating groups for copper(II). Polymeric beads with the chelating agents triethylenetetramine, N,N-di(2-pyridylmethyl)amine, and 8-hydroxyquinoline (8HQB) were investigated. In a preliminary copper uptake experiment, we found that 8HQB significantly reduced copper uptake (using copper-64 as a radiotracer) after oral administration in Wistar rats. Furthermore, we measured organ radioactivity in rats to demonstrate that 8HQB radiolabelled with iodine-125 is not absorbed from the gastrointestinal tract after oral administration. Non-resorbability and the blockade of copper uptake were also confirmed with small animal imaging (PET/CT) in mice. In a long-term experiment with Wistar rats fed a diet containing the polymers, we have found that there were no signs of polymer toxicity and the addition of polymers to the diet led to a significant reduction in the copper contents in the kidneys, brains, and livers of the rats. We have shown that polymers containing specific ligands could potentially be novel therapeutics for Wilson's disease. PMID:24815561

  6. Hematein chelates of unusual metal ions for tinctorial histochemistry.

    PubMed

    Smith, A A

    2010-02-01

    Hematoxylin is oxidized easily to hematein, an excellent stain for metal ions. If it already is bound to a substrate, the metal ion becomes a mordant linking the dye to the substrate. Metal ions added to hematein in solution are chelated by the hematein to form a lake. Most of these chelates stain animal tissues. They usually are bound to the tissue by a combination of hydrogen bonding of the hematein and ionic bonding of the metal ion. When binding of the lake to the tissue occurs by way of the metal ion, the metal ion is a mordant. Mordant staining often is specific. Chromium hematoxylin binds to strong acids; it can be made selective for protein-bound sulfonic acids. Zirconyl hematoxylin is selective for acidic mucins. Mucihematein can be made selective for all acidic mucins or for sulfomucins alone. Bismuth hematoxylin appears to be selective for the guanido group of arginine and there is some evidence that the bonding is covalent. Although it is not a histochemical stain, copper-chrome hematoxylin is an excellent stain for organelles with double membranes, i.e., mitochondria and nuclei. PMID:19575317

  7. Using iron chelating agents to enhance dermatological PDT

    NASA Astrophysics Data System (ADS)

    Curnow, Alison; Dogra, Yuktee; Winyard, Paul; Campbell, Sandra

    2009-06-01

    Topical protoporphyrin IX (PPIX) induced photodynamic therapy (PDT) of basal cell carcinoma (BCC) produces good clinical outcomes with excellent cosmesis as long as the disease remains superficial. Efficacy for nodular BCC however appears inferior to standard treatment unless repeat treatments are performed. Enhancement is therefore required and is possible by employing iron chelating agents to temporarily increase PPIX accumulation above the levels normally obtained using aminolevulinic acid (ALA) or the methyl ester of ALA (MAL) alone. In vitro studies investigated the effect of the novel iron chelator, CP94 on necrotic or apoptotic cell death in cultured human skin fibroblasts and epidermal carcinoma cells incubated with MAL. Furthermore, following a dose escalating safety study conducted with ALA in patients, an additional twelve nodular BCCs were recruited for topical treatment with standard MAL-PDT +/- increasing doses of CP94. Six weeks later following clinical assessment, the whole treatment site was excised for histological analysis. CP94 produced greater cell death in vitro when administered in conjunction with MAL than this porphyrin precursor could produce when administered alone. Clinically, PDT treatment using Metvix + CP94 was a simple and safe modification associated with a trend of reduced tumor thickness with increasing CP94 dose.

  8. Immobilization of alcohol dehydrogenase onto metal-chelated cryogels.

    PubMed

    Uygun, Deniz Akta?; Akduman, Begm; Uygun, Murat; Akgl, Sinan; Denizli, Adil

    2015-01-01

    In this presented work, poly(HEMA-GMA) cryogel was synthesized and used for the immobilization of alcohol dehydrogenase. For this, synthesized cryogels were functionalized with iminodiacetic acid and chelated with Zn(2+). This metal-chelated cryogels were used for the alcohol dehydrogenase immobilization and their kinetic parameters were compared with free enzyme. Optimum pH was found to be 7.0 for both immobilized and free enzyme preparations, while temperature optima for free and immobilized alcohol dehydrogenase was 25 C. Kinetic constants such as K(m), V(max), and k(cat) for free and immobilized form of alcohol dehydrogenase were also investigated. k(cat) value of free enzyme was found to be 3743.9 min(-1), while k(cat) for immobilized enzyme was 3165.7 min(-1). Thermal stability of the free and immobilized alcohol dehydrogenase was studied and stability of the immobilized enzyme was found to be higher than free form. Also, operational stability and reusability profile of the immobilized alcohol dehydrogenase were investigated. Finally, storage stability of the free and immobilized alcohol dehydrogenase was studied, and at the end of the 60 days storage, it was demonstrated that, immobilized alcohol dehydrogenase was exhibited high stability than that of free enzyme. PMID:25715869

  9. Optically Switchable Chelates: Optical Control and Sensing of Metal Ions

    PubMed Central

    Sakata, Tomoyo; Jackson, David K.; Mao, Shu; Marriott, Gerard

    2008-01-01

    This study introduces new concepts in the design, synthesis, and in vitro and in vivo characterization, manipulation, and imaging of organic chelates whose association with metal ions is rapidly and reversibly controlled by using light. Di- and tricarboxylic group bearing photochromes, nitrobenzospiropyran (nitroBIPS), undergo rapid and reversible, optically driven transitions between their spiro (SP) and fluorescent merocyanine (MC) states. The MC state of nitroBIPS-8-DA binds tightly to various metal ions resulting in specific shifts in absorption and fluorescence, and the dissociation constant for its Gadolinium complex in water is measured at ~5 ?M. The metal-bound MC state is converted to the weaker-binding SP state with use of 543 nm light, while the SP to MC transition is complete with use of 365 or 720 nm (2-photon) light within several microseconds. Fluorescence imaging of the MC state of nitroBIPS-8-TriA was used to quantify the rate and efficiency of optical switching and to provide a real-time readout of the state of the optically switchable chelate within living cells. PMID:18072788

  10. Sorption of trace heavy metals by thiol containing chelating resins

    SciTech Connect

    Saha, B.; Iglesias, M.; Cumming, I.W.; Streat, M.

    2000-01-01

    The sorption of copper, cadmium, nickel and zinc ions on thiol (-SH) based chelating polymeric resins (thiomethyl resin and Duolite GT-73) has been investigated. The physical and chemical characterization of these polymers in the form of scanning electron micrographs (SEM), BET and Langmuir surface area measurements. Fourier transform infra red spectroscopy (FTIR) analysis, X-ray photoelectron spectroscopy (XPS) analysis, atomic composition measurement, sodium capacity determination and zeta potential measurements have been conducted to assess their performance as sorbents for trace toxic metal removal. Density functional theory (DFT) has been used to analyze the pore size distribution data. The adsorption of metal ions from aqueous solution on these sorbents has been studied in batch equilibrium experiments. The influence of pH on metal adsorption capacity has also been examined. The kinetic performance of these polymers has been assessed and the results have been analyzed by a pore diffusion model. The resins have been used in mini-columns to study the selectivity towards the desired metal ion. The desorption of metal ions has been studied using hydrochloric acid (1 M and 4 M), sulfuric acid (1 M and 4 M) and acidified thiourea. The present study confirms that these thiol based chelating resins are very effective for selective removal of trace heavy metals from water.

  11. Branched polymeric media: boron-chelating resins from hyperbranched polyethylenimine.

    PubMed

    Mishra, Himanshu; Yu, Changjun; Chen, Dennis P; Goddard, William A; Dalleska, Nathan F; Hoffmann, Michael R; Diallo, Mamadou S

    2012-08-21

    Extraction of boron from aqueous solutions using selective resins is important in a variety of applications including desalination, ultrapure water production, and nuclear power generation. Today's commercial boron-selective resins are exclusively prepared by functionalization of styrene-divinylbenzene (STY-DVB) beads with N-methylglucamine to produce resins with boron-chelating groups. However, such boron-selective resins have a limited binding capacity with a maximum free base content of 0.7 eq/L, which corresponds to a sorption capacity of 1.16 0.03 mMol/g in aqueous solutions with equilibrium boron concentration of ?70 mM. In this article, we describe the synthesis and characterization of a new resin that can selectively extract boron from aqueous solutions. We show that branched polyethylenimine (PEI) beads obtained from an inverse suspension process can be reacted with glucono-1,5-D-lactone to afford a resin consisting of spherical beads with high density of boron-chelating groups. This resin has a sorption capacity of 1.93 0.04 mMol/g in aqueous solution with equilibrium boron concentration of ?70 mM, which is 66% percent larger than that of standard commercial STY-DVB resins. Our new boron-selective resin also shows excellent regeneration efficiency using a standard acid wash with a 1.0 M HCl solution followed by neutralization with a 0.1 M NaOH solution. PMID:22827255

  12. Competition among marine phytoplankton for different chelated iron species

    NASA Astrophysics Data System (ADS)

    Hutchins, David A.; Witter, Amy E.; Butler, Alison; Luther, George W.

    1999-08-01

    Dissolved-iron availability plays a critical role in controlling phytoplankton growth in the oceans,. The dissolved iron is overwhelmingly (~99%) bound to organic ligands with a very high affinity for iron, but the origin, chemical identity and biological availability of this organically complexed Fe is largely unknown. The release into sea water of complexes that strongly chelate iron could result from the inducible iron-uptake systems of prokaryotes (siderophore complexes) or by processes such as zooplankton-mediated degradation and release of intracellular material (porphyrin complexes). Here we compare the uptake of siderophore- and porphyrin-complexed 55Fe by phytoplankton, using both cultured organisms and natural assemblages. Eukaryotic phytoplankton efficiently assimilate porphyrin-complexed iron, but this iron source is relatively unavailable to prokaryotic picoplankton (cyanobacteria). In contrast, iron bound to a variety of siderophores is relatively more available to cyanobacteria than to eukaryotes, suggesting that the two plankton groups exhibit fundamentally different iron-uptake strategies. Prokaryotes utilize iron complexed to either endogenous or exogenous siderophores, whereas eukaryotes may rely on a ferrireductase system, that preferentially accesses iron chelated by tetradentate porphyrins, rather than by hexadentate siderophores. Competition between prokaryotes and eukaryotes for organically-bound iron may therefore depend on the chemical nature of available iron complexes, with consequences for ecological niche separation, plankton community size-structure and carbon export in low-iron waters.

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

    PubMed

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

    2016-03-01

    Iron (Fe) is an essential element for many organisms, but high concentrations of iron can be toxic. The complex relation between iron, arsenic (As), bacteria, and organic matter in sediments and groundwater is still an issue of environmental concern. The present study addresses the effects of humic acids and microorganisms on the mobilization of iron in sediments from an arsenic-affected area, and the microbial diversity was analyzed. The results showed that the addition of 50, 100, and 500 mg/L humic acids enhanced ferrous iron (Fe(II)) release in a time-dependent and dose-dependent fashion under anaerobic conditions. A significant increase in the soluble Fe(II) concentrations occurred in the aqueous phases of the samples during the first 2 weeks, and aqueous Fe(II) reached its maximum concentrations after 8 weeks at the following Fe(II) concentrations: 28.95 ± 1.16 mg/L (original non-sterilized sediments), 32.50 ± 0.71 mg/L (50 mg/L humic acid-amended, non-sterilized sediments), 37.50 ± 1.85 mg/L (100 mg/L humic acid-amended, non-sterilized sediments), and 39.00 ± 0.43 mg/L (500 mg/L humic acid-amended, non-sterilized sediments). These results suggest that humic acids can further enhance the microbially mediated release of sedimentary iron under anaerobic conditions. By contrast, very insignificant amounts of iron release were observed from sterilized sediments (the abiotic controls), even with the supplementation of humic acids under anaerobic incubation. In addition, the As(III) release was increased from 50 ± 10 μg/L (original non-sterilized sediments) to 110 ± 45 μg/L (100 mg/L humic acid-amended, non-sterilized sediments) after 8 weeks of anaerobic incubation. Furthermore, a microbial community analysis indicated that the predominant class was changed from Alphaproteobacteria to Deltaproteobacteria, and clearly increased populations of Geobacter sp., Paludibacter sp., and Methylophaga sp. were found after adding humic acids along with the increased release of iron and arsenic. Our findings provide evidence that humic acids can enhance the microbially mediated release of sedimentary ferrous iron in an arsenic-affected area. It is thus suggested that the control of anthropogenic humic acid use and entry into the environment is important for preventing the subsequent iron contamination in groundwater. PMID:25997809

  14. Uranyl binary and ternary chelates of tenoxicam. Synthesis, spectroscopic and thermal characterization of ternary chelates of tenoxicam and alanine with transition metals

    NASA Astrophysics Data System (ADS)

    El-Gamel, Nadia E. A.

    2007-11-01

    Ternary Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and UO 2(II) chelates with tenoxicam (Ten) drug (H 2L 1) and dl-alanine (Ala) (HL 2) and also the binary UO 2(II) chelate with Ten were studied. The structures of the chelates were elucidated using elemental, molar conductance, magnetic moment, IR, diffused reflectance and thermal analyses. UO 2(II) binary chelate was isolated in 1:2 ratio with the formula [UO 2(H 2L) 2](NO 3) 2. The ternary chelates were isolated in 1:1:1 (M:H 2L 1:L 2) ratios and have the general formulae [M(H 2L 1)(L 2)(Cl) n(H 2O) m] yH 2O (M = Fe(III) ( n = 2, m = 0, y = 2), Co(II) ( n = 1, m = 1, y = 2) and Ni(II) ( n = 1, m = 1, y = 3)); [M(H 2L 1)(L 2)](X) z yH 2O (M = Cu(II) (X = AcO, z = 1, y = 0), Zn(II) (X = AcO, z = 1, y = 3) and UO 2(II) (X = NO 3, z = 1, y = 2)). IR spectra reveal that Ten behaves as a neutral bidentate ligand coordinated to the metal ions via the pyridine-N and carbonyl-O groups, while Ala behaves as a uninegatively bidentate ligand coordinated to the metal ions via the deprotonated carboxylate-O and amino-N. The magnetic and reflectance spectral data confirm that all the chelates have octahedral geometry except Cu(II) and Zn(II) chelates have tetrahedral structures. Thermal decomposition of the chelates was discussed in relation to structure and different thermodynamic parameters of the decomposition stages were evaluated.

  15. ADSORPTION AND LIGAND-ASSISTED FEOOH(GOETHITE) DISSOLUTION BY AMINOCARBOXYLATE CHELATING AGENTS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In order for extracellular chelating agents to solubilize Fe(III) (hydr)oxides, the following criteria must be met: 1. The chelating agent must adsorb. Amine groups structurally close to a carboxylate group strongly diminish adsorption (via hydrogen-bonding), while distal amine groups slightly dimi...

  16. [FTIR spectroscopic study on synthesis and adsorption performance of amino phosphonic acid chelating fiber].

    PubMed

    Feng, Chang-Gen; Sun, Yao-Ran; Li, Ming-Yu; Zeng, Qing-Xuan; Liang, Chun-Bo

    2012-12-01

    During the preparation of amino phosphoric chelating fiber, polypropylene grafted styrene, acetyl, amine series and amino phosphonic acid chelating fibers were certified by infrared spectrum, and the functionalization degree of raw fibers was studied. By the semi-qualitative method of infrared spectrum, the adsorption performance of indium and copper on amino phosphonic chelating fiber was also discussed. The results showed that (1) The peak at 1 116 cm(-1) was assigned to--P(ONa)2 in amino phosphonic acid chelating fiber. So the success of phosphorylation was verified. (2) During preparation, the phosphorylation effect of amino phosphonic acid chelating fiber could be reflected by the change of the peaks at 1 056 and 1 110 cm(-)1. (3) After adsorption of In3+ on amino phosphonic acid chelating fiber, the new forming N-In coordination key was absorbed strongly at the bands of 1 000-1 200 cm(-1) and at 1 107, 699 and 617 cm(-1). After adsorption Cu2+ on amino phosphonic acid chelating fiber two new strong and wide peaks were found at 1 110 and 618 cm(-1), respectively. (4) Through the area change of the bands at 1 200-900 and 600 cm(-1), the adsorption performance of indium and copper on amino phosphonic acid chelating fiber was compared. PMID:23427532

  17. Removal of heavy metals from a chelated solution with electrolytic foam separation

    SciTech Connect

    Min-Her Leu; Juu-En Chang; Ming-Sheng Ko

    1994-11-01

    An experimental study was conducted on the chelation and electrolytic foam separation of trace amounts of copper, nickel, zinc, and cadmium from a synthetic chelated metal wastewater. Sodium ethylenediaminetetraacetate (EDTA), citrate, sodium diethyldithiocarbamate (NDDTC), and potassium ethyl xanthate (KEtX) were used with sodium dodecylsulfate (NaDS) as a foam-producing agent. Experimental results from an electrolytic foam separation process showed that chelating agents NDDTC and KEtX, due to their higher chelating strength and hydrophobic property, can efficiently separate Cu and Ni from chelated compounds (Cu, Ni/EDTA, and Cu, Ni/citrate). In a Cu-EDTA-NDDTC system with a chelating agent/metal ratio of 4, the residual Cu(II) concentration is 0.7 mg/L. The effects of chelating agent types and different chelating agents concentrations on the removal of metal ions were studied. The effect of NaDS dosage on flotation behavior and the efficiency of metal removal were also investigated.

  18. Effects of chelating agents on protein, oil, fatty acid amd seed mineral concentrations in soybean

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soybean seed is a major source of protein and oil for human diet. Since not much information is available on the effects of chelating agents on soybean seed composition constituents, the current study aimed to investigate the effects of various chelating agents on soybean [(Glycine max (L.) Merr.)] ...

  19. Membrane-permeant chelators can attenuate Zn2+-induced cortical neuronal death.

    PubMed

    Canzoniero, Lorella M T; Manzerra, Pat; Sheline, Christian T; Choi, Dennis W

    2003-09-01

    Chelating extracellular Zn(2+) with the membrane-impermeant Zn(2+) chelator, CaEDTA, can inhibit toxic Zn(2+) influx and subsequent neuronal death. However, this drug does not cross the blood-brain barrier. In the present study, we explored the ability of two membrane-permeant Zn(2+) chelators to inhibit Zn(2+)-induced death of cultured cortical neurons. Addition of either the high affinity (K(D)=10(-15.6)) Zn(2+) chelator, N, N, N', N', tetrakis (2-pyridylmethyl) etylenediaminepentaethylene (TPEN), or the low affinity (K(D)=10(-6)) Zn(2+) chelator, 1-hydroxypyridine-2-thione (pyrithione), to the culture medium following exposure to extracellular Zn(2+) reduced subsequent neuronal death, even if chelator administration was delayed by up to 1 h. Indeed, some delay was essential for neuroprotection with pyrithione, as co-administration of pyrithione together with extracellular Zn(2+) increased levels of [Zn(2+)](i) and cell death compared to the levels induced by Zn(2+) alone. TPEN, but not pyrithione, was intrinsically toxic at high concentrations, likely due to excessive chelation of [Zn(2+)](i), as this intrinsic toxicity was reduced by prior addition of extracellular Zn(2+). These data point to a potential therapeutic role for membrane-permeant Zn(2+) chelators, perhaps especially possessing low Zn(2+) affinity, in attenuating neuronal death after certain acute insults. PMID:12871659

  20. Inhibitory activity of chelating agent against bacteria associated with poultry processing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ethylenediaminetetraacetic acid (EDTA) and ethylenediamine-N, N’-disuccinic acid (EDDS) are chelating agents that can bind minerals that produce water hardness. By sequestering minerals in hard water, chelators reduce water hardness and increase the ability of cleansers to remove dirt and debris dur...

  1. Leaching of zinc sulfide by Thiobacillus ferrooxidans: Bacterial oxidation of the sulfur product layer increases the rate of zinc sulfide dissolution at high concentrations of ferrous ions

    SciTech Connect

    Fowler, T.A.; Crundwell, F.K.

    1999-12-01

    This paper reports the results of leaching experiments conducted with and without Thiobacillus ferroxidans at the same conditions in solution. The extent of leaching of ZnS with Bacteria is significantly higher than that without bacteria at high concentrations of ferrous ions. A porous layer of elemental sulfur is present on the surfaces of the chemically leached particles, which no sulfur is present on the surfaces of the bacterially leached particles. The analysis of the data using the shrinking-core model shows that the chemical leaching of ZnS is limited by the diffusion of ferrous ions through the sulfur product layer at high concentrations of ferrous ions. The analysis of the data shows that diffusion through the product layer does not limit the rate of dissolution when bacteria are present. This suggests that the action of T.ferroxidans in oxidizing the sulfur formed on the particle surface is to remove the barrier to diffusion by ferrous ions.

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

    PubMed

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

    2015-12-01

    Hydrogen peroxide is an important regulator of protein tyrosine phosphatase activity via reversible oxidation. However, the role of iron in this reaction has not been yet elucidated. Here we compare the influence of hydrogen peroxide and the ferrous iron (reagent for Fenton reaction) on the enzymatic activity of recombinant CD45, LAR, PTP1B phosphatases and cellular CD45 in Jurkat cells. The obtained results show that ferrous iron (II) is potent inhibitor of CD45, LAR and PTP1B, but the inhibitory effect is concentration dependent. We found that the higher concentrations of ferrous iron (II) increase the inactivation of CD45, LAR and PTP1B phosphatase caused by hydrogen peroxide, but the addition of the physiological concentration (500 nM) of ferrous iron (II) has even a slightly preventive effect on the phosphatase activity against hydrogen peroxide. PMID:26407665

  3. An experimental determination of ferrous chloride and acetate complexation in aqueous solutions to 300[degrees]C

    SciTech Connect

    Palmer, D.A. ); Hyde, K.E. )

    1993-04-01

    Reliable thermodynamic information on the stability of ferrous chloride complexes at high temperatures is important to evaluations of iron transport in hydrothermal fluids, and to the power industry for iron corrosion and transport in the water/steam cycle. The formation of the monochloroiron(II) complex, FeCl[sup +], was studied potentiometrically from 125 to 295[degrees]C at 25 degree intervals at one molal ionic strength in aqueous solutions containing acetic acid, sodium acetate, and sodium trifluoromethanesulfonate. In this method, competition between chloride and acetate ions for the ferrous cation resulted in a change in solution pH, which in turn was monitored in situ in a hydrogen-electrode, concentration cell. A simple empirical approach was used to extrapolate these formation quotients to infinite dilution. The resulting constants proved to be in excellent agreement with previous spectrophotometric results obtained from 25 to 200[degrees]C. Thus, the present study confirms the validity of the conclusions made based on these earlier data concerning the solubility of Fe-containing minerals in hydrothermal brines. Formation constants at infinite dilution for FeCl[sup +] are compared with the stability of ferrous acetate and hydroxide complexes. The original potentiometric titration data for ferrous acetate complex formation were combined in a new fit with values determined from the present study at unit ionic strength. Two empirical treatments (namely the isocoulombic method and the temperature/water density function) were considered for fitting and extrapolating the infinite dilution formation constants to 350[degrees]C. 40 refs., 12 figs., 5 tabs.

  4. Alginate Inhibits Iron Absorption from Ferrous Gluconate in a Randomized Controlled Trial and Reduces Iron Uptake into Caco-2 Cells

    PubMed Central

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

    2014-01-01

    Previous in vitro results indicated that alginate beads might be a useful vehicle for food iron fortification. A human study was undertaken to test the hypothesis that alginate enhances iron absorption. A randomised, single blinded, cross-over trial was carried out in which iron absorption was measured from serum iron appearance after a test meal. Overnight-fasted volunteers (n?=?15) were given a test meal of 200 g cola-flavoured jelly plus 21 mg iron as ferrous gluconate, either in alginate beads mixed into the jelly or in a capsule. Iron absorption was lower from the alginate beads than from ferrous gluconate (8.5% and 12.6% respectively, p?=?0.003). Sub-group B (n?=?9) consumed the test meals together with 600 mg calcium to determine whether alginate modified the inhibitory effect of calcium. Calcium reduced iron absorption from ferrous gluconate by 51%, from 11.5% to 5.6% (p?=?0.014), and from alginate beads by 37%, from 8.3% to 5.2% (p?=?0.009). In vitro studies using Caco-2 cells were designed to explore the reasons for the difference between the previous in vitro findings and the human study; confirmed the inhibitory effect of alginate. Beads similar to those used in the human study were subjected to simulated gastrointestinal digestion, with and without cola jelly, and the digestate applied to Caco-2 cells. Both alginate and cola jelly significantly reduced iron uptake into the cells, by 34% (p?=?0.009) and 35% (p?=?0.003) respectively. The combination of cola jelly and calcium produced a very low ferritin response, 16.5% (p<0.001) of that observed with ferrous gluconate alone. The results of these studies demonstrate that alginate beads are not a useful delivery system for soluble salts of iron for the purpose of food fortification. Trial Registration ClinicalTrials.gov NCT01528644 PMID:25391138

  5. First-principles study of intermediate-spin ferrous iron in the Earth's lower mantle

    NASA Astrophysics Data System (ADS)

    Hsu, Han; Wentzcovitch, Renata M.

    2014-11-01

    Spin crossover of iron is of central importance in solid Earth geophysics. It impacts all physical properties of minerals that altogether constitute 95 vol% of the Earth's lower mantle: ferropericlase [(Mg,Fe)O] and Fe-bearing magnesium silicate (MgSiO3) perovskite. Despite great strides made in the past decade, the existence of an intermediate-spin (IS) state in ferrous iron (Fe2 +) (with total electron spin S =1 ) and its possible role in the pressure-induced spin crossover in these lower-mantle minerals still remain controversial. Using density functional theory + self-consistent Hubbard U (DFT+Usc ) calculations, we investigate all possible types of IS states of Fe2 + in (Mg,Fe)O and (Mg,Fe)SiO3 perovskite. Among the possible IS states in these minerals, the most probable IS state has an electronic configuration that significantly reduces the electron overlap and the iron nuclear quadrupole splitting (QS). These most probable IS states, however, are still energetically disfavored, and their QSs are inconsistent with Mssbauer spectra. We therefore conclude that IS Fe2 + is highly unlikely in the Earth's lower mantle.

  6. Development of a New Ferrous Aluminosilicate Refractory Material for Investment Casting of Aluminum Alloys

    NASA Astrophysics Data System (ADS)

    Yuan, Chen; Jones, Sam; Blackburn, Stuart

    2012-12-01

    Investment casting is a time-consuming, labour intensive process, which produces complex, high value-added components for a variety of specialised industries. Current environmental and economic pressures have resulted in a need for the industry to improve current casting quality, reduce manufacturing costs and explore new markets for the process. Alumino-silicate based refractories are commonly used as both filler and stucco materials for ceramic shell production. A new ceramic material, norite, is now being produced based on ferrous aluminosilicate chemistry, having many potential advantages when used for the production of shell molds for casting aluminum alloy. This paper details the results of a direct comparison made between the properties of a ceramic shell system produced with norite refractories and a typical standard refractory shell system commonly used in casting industry. A range of mechanical and physical properties of the systems was measured, and a full-scale industrial casting trial was also carried out. The unique properties of the norite shell system make it a promising alternative for casting aluminum based alloys in the investment foundry.

  7. Control of ferrous iron oxidation within circumneutral microbial iron mats by cellular activity and autocatalysis.

    PubMed

    Rentz, Jeremy A; Kraiya, Charoenkwan; Luther, George W; Emerson, David

    2007-09-01

    Ferrous iron (Fe2+) oxidation by microbial iron mat samples, dominated by helical stalks of Gallionella ferruginea or sheaths of Leptothrix ochracea, was examined. Pseudo-first-order rate constants for the microbial mat samples ranged from 0.029 +/- 0.004 to 0.249 +/- 0.042 min(-1) and correlated well with iron content (R2 = 0.929). Rate constants for Na azide-treated (1 mM) samples estimated autocatalytic oxidation by iron oxide stalks or sheaths, with values ranging from 0.016 +/- 0.008 to 0.062 +/- 0.006 min(-1). Fe2+ oxidation attributable to cellular activities was variable with respect to sampling location and sampling time, with rate constants from 0.013 +/- 0.005 to 0.187 +/- 0.037 min(-1). Rates of oxidation of the same order of magnitude for cellular processes and autocatalysis suggested that bacteria harnessing Fe2+ as an energy source compete with their own byproducts for growth, not chemical oxidation (under conditions where aqueous oxygen concentrations are less than saturating). The use of cyclic voltammetry within this study for the simultaneous measurement of Fe2+ and oxygen allowed the collection of statistically meaningful and reproducible data, two factors that have limited aerobic, circumneutral, Fe2+ -oxidation rate studies. PMID:17937285

  8. Small Angle Neutron Scattering Study of Nano Sized Precipitates in Ferrous Alloys.

    PubMed

    Han, Young-Soo; Park, Duck-Gun; Kobayashi, Satoru

    2015-11-01

    Nano-sized precipitates in a Fe-1 wt% Cu alloy were studied by SANS (Small Angle Neutron Scattering). The SANS experiments were performed with the 40 m SANS instrument at HANARO. Due to the ferromagnetic nature of the ferrous alloys, a horizontal magnetic field of 1 Tesla was applied during the SANS experiment. The nano-sized Cu precipitates were quantitatively analyzed by SANS in the Fe-1 wt% Cu alloy. The size of the precipitates increased from 2 nm to 4 nm with increasing aging time from 20 min. to 1800 min. at 753 K. The measured A-ratio obtained from SANS data increased from 2.2 to 6.6 with increasing aging time. It is surmised that Cu clusters containing a large amount of Fe are initiated at the early stage of aging and the Fe content in the Cu precipitate decreases with increasing aging time and eventually an almost pure BCC Cu precipitate is formed. PMID:26726560

  9. Lung cancer in a non-ferrous smelter: the role of cadmium.

    PubMed Central

    Ades, A E; Kazantzis, G

    1988-01-01

    Lung cancer mortality was examined in a cohort of 4393 men employed at a zinc-lead-cadmium smelter. There was an excess of lung cancer (overall SMR = 124.5, 95% confidence interval 107-144) which was particularly evident for those employed for more than 20 years. A statistically significant trend in SMRs with increasing duration of employment was apparent. Quantitative estimates of exposure to cadmium and ordinal rankings for lead, arsenic, zinc, sulphur dioxide, and dust were used to calculate cumulative exposures from job histories. Matched logistic regression was used to compare the cumulative exposures of cases of lung cancer to those of controls matched for date of birth and date of starting work and surviving at the time of death of the matched cases. The increasing risk of lung cancer associated with increasing duration of employment could not be accounted for by cadmium and did not appear to be restricted to any particular process or department. Although lung cancer mortality was associated with estimates of cumulative exposure to arsenic and to lead, it was not possible to determine whether the increased risk might be due to arsenic, lead, or to other contaminants in the smelter. These results are compared with findings from other non-ferrous smelters. PMID:3395580

  10. Abiotic reductive dechlorination of cis-DCE by ferrous monosulfide mackinawite.

    PubMed

    Hyun, Sung Pil; Hayes, Kim F

    2015-11-01

    Cis-1,2,-dichloroethylene (cis-DCE) is a toxic, persistent contaminant occurring mainly as a daughter product of incomplete degradation of perchloroethylene (PCE) and trichloroethylene (TCE). This paper reports on abiotic reductive dechlorination of cis-DCE by mackinawite (FeS1-x), a ferrous monosulfide, under variable geochemical conditions. To assess in situ abiotic cis-DCE dechlorination by mackinawite in the field, mackinawite suspensions prepared in a field groundwater sample collected from a cis-DCE contaminated field site were used for dechlorination experiments. The effects of geochemical variables on the dechlorination rates were monitored. A set of dechlorination experiments were also carried out in the presence of aquifer sediment from the site over a range of pH conditions to better simulate the actual field situations. The results showed that the suspensions of freshly prepared mackinawite reductively transformed cis-DCE to acetylene, whereas the conventionally prepared powder form of mackinawite had practically no reactivity with cis-DCE under the same experimental conditions. Significant cis-DCE degradation by mackinawite has not been reported prior to this study, although mackinawite has been shown to reductively transform PCE and TCE. This study suggests feasibility of using mackinawite for in situ remediation of cis-DCE-contaminated sites with high S levels such as estuaries under naturally achieved or stimulated sulfate-reducing conditions. PMID:26278897

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

    SciTech Connect

    Kyser, E.; O'Rourke, P.

    2013-12-10

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

  12. Ferrous ions as catalysts for photochemical reduction of CO{sub 2} in homogeneous solutions

    SciTech Connect

    Grodkowski, J.; Neta, P.

    2000-05-18

    Ferrous ions are found to catalyze the photochemical reduction of CO{sub 2} to CO in acetonitrile (ACN) solutions containing triethylamine (TEA) or triethanolamine (TEOA) as reductive quenchers and p-terphenyl (TP) as a photosensitizer. TP is photoreduced to form the radical anion, TP{sup {sm_bullet}{minus}}, which reduces Fe(II) ions. The rate constant for the reduction of Fe(II) by TP{sup {sm_bullet}{minus}} was determined by pulse radiolysis in ACN/TEOA solutions and found to be (1.2 {+-} 0.4) x 10{sup 8} L mol{sup {minus}1}s{sup {minus}1}. The Fe(I) ions produced are expected to react with Co{sub 2} to form an adduct that is equivalent to the adduct known to be formed upon reaction of CO{sub 2}{sup {sm_bullet}{minus}} with Fe(II) complexes. Subsequent reduction of the Fe-CO{sub 2} adduct leads to formation of CO. Fe(I) can also undergo protonation and form H{sub 2}. After extensive irradiation, photochemical production of CO stops, probably due to competition between CO and CO{sub 2} for the Fe(I) binding sites. Addition of CO to the solution enhances the photochemical production of H{sub 2}.

  13. Investigation and analysis of ferrous sulfate polyvinyl alcohol (PVA) gel dosimeter

    NASA Astrophysics Data System (ADS)

    Hill, Brendan; Bäck, Sven Å. J.; Lepage, Martin; Simpson, John; Healy, Brendan; Baldock, Clive

    2002-12-01

    Ferrous sulfate (Fe(SO4)2) PVA gels were investigated for a range of absorbed doses up to 20 Gy using both magnetic resonance imaging (MRI) and spectrophotometry to determine R1 and optical density (OD) dose responses and G values. It was found that R1- and OD-dose sensitivities increased with O2 saturation or by the introduction of a freeze-thaw cycle during preparation of the PVA gel. The storage temperature of the Fe(SO4)2 PVA gel at -18 °C increased R1-dose sensitivity above that of gels stored at 5 °C. The addition of sucrose to the formulation was found to result in the largest increase in both R1- and OD-dose sensitivities. Fe(SO4)2 PVA gel with and without the addition of xylenol orange was demonstrated to have a G value of ~20 ions/100 eV and with sucrose ~24 ions/100 eV.

  14. Role of Ferrous Ions in Synthetic Cobaltous Sulfide Leaching of Thiobacillus ferrooxidans

    PubMed Central

    Sugio, Tsuyoshi; Domatsu, Chitoshi; Tano, Tatsuo; Imai, Kazutami

    1984-01-01

    Microbiological leaching of synthetic cobaltous sulfide (CoS) was investigated with a pure strain of Thiobacillus ferroxidans. The strain could not grow on CoS-salts medium in the absence of ferrous ions (Fe2+). However, in CoS-salts medium supplemented with 18 mM Fe2+, the strain utilized both Fe2+ and the sulfur moiety in CoS for growth, resulting in an enhanced solubilization of Co2+. Cell growth on sulfur-salts medium was strongly inhibited by Co2+, and this inhibition was completely protected by Fe2+. Cobalt-resistant cells, obtained by subculturing the strain in medium supplemented with both Fe2+ and Co2+, brought a marked decrease in the amount of Fe2+ absolutely required for cell growth on CoS-salts medium. As one mechanism of protection by Fe2+, it is proposed that the strain utilizes one part of Fe2+ externally added to CoS-salts medium to synthesize the cobalt-resistant system. Since a similar protective effect by Fe2+ was also observed for cell inhibition by stannous, nickel, zinc, silver, and mercuric ions, a new role of Fe2+ in bacterial leaching in T. ferrooxidans is proposed. PMID:16346615

  15. Vibrational Assignments of Six-Coordinate Ferrous Heme Nitrosyls: New Insight From Nuclear Resonance Vibrational Spectroscopy

    SciTech Connect

    Paulat, F.; Berto, T.C.; George, S.DeBeer; Goodrich, L.; Praneeth, V.K.K.; Sulok, C.D.; Lehnert, N.

    2009-05-21

    This Communication addresses a long-standing problem: the exact vibrational assignments of the low-energy modes of the Fe-N-O subunit in six-coordinate ferrous heme nitrosyl model complexes. This problem is addressed using nuclear resonance vibrational spectroscopy (NRVS) coupled to {sup 15}N{sup 18}O isotope labeling and detailed simulations of the obtained data. Two isotope-sensitive features are identified at 437 and 563 cm{sup -1}. Normal coordinate analysis shows that the 437 cm{sup -1} mode corresponds to the Fe-NO stretch, whereas the 563 cm{sup -1} band is identified with the Fe-N-O bend. The relative NRVS intensities of these features determine the degree of vibrational mixing between the stretch and the bend. The implications of these results are discussed with respect to the trans effect of imidazole on the bound NO. In addition, a comparison to myoglobin-NO (Mb-NO) is made to determine the effect of the Mb active site pocket on the bound NO.

  16. Enhanced and Stabilized Arsenic Retention in Microcosms through the Microbial Oxidation of Ferrous Iron by Nitrate

    PubMed Central

    SUN, JING; CHILLRUD, STEVEN N.; MAILLOUX, BRIAN J.; STUTE, MARTIN; SINGH, RAJESH; DONG, HAILIANG; LEPRE, CHRISTOPHER J.; BOSTICK, BENJAMIN C.

    2016-01-01

    Magnetite strongly retains As, and is relatively stable under Fe(III)-reducing conditions common in aquifers that release As. Here, laboratory microcosm experiments were conducted to investigate a potential As remediation method involving magnetite formation, using groundwater and sediments from the Vineland Superfund site. The microcosms were amended with various combinations of nitrate, Fe(II)(aq)(as ferrous sulfate) and lactate, and were incubated for more than 5 weeks. In the microcosms enriched with 10 mM nitrate and 5 mM Fe(II)(aq), black magnetic particles were produced, and As removal from solution was observed even under sustained Fe(III) reduction stimulated by the addition of 10 mM lactate. The enhanced As retention was mainly attributed to co-precipitation within magnetite and adsorption on a mixture of magnetite and ferrihydrite. Sequential chemical extraction, X-ray absorption spectroscopy and magnetic susceptibility measurements showed that these minerals formed at pH 6 – 7 following nitrate-Fe(II) addition, and As-bearing magnetite was stable under reducing conditions. Scanning electron microscopy and X-ray diffraction indicated that nano-particulate magnetite was produced as coatings on fine sediments, and no aging effect was detected on morphology over the course of incubation. These results suggest that a magnetite based strategy may be a long-term remedial option for As-contaminated aquifers. PMID:26454120

  17. The chemistry of the thermal decomposition of pseudobrookite ferrous titanium oxides

    SciTech Connect

    Teller, R.G.; Antonio, M.R. ); Grau, A.E.; Gueguin, M. ); Kostiner, E. )

    1990-10-01

    The thermal decomposition of two metastable ferrous titanium oxide compounds of commercial interest have been studied by in situ x-ray and neutron diffraction at elevated temperatures as well as by {sup 57}Fe Mossbauer effect spectroscopy. Thermal decomposition was monitored by collecting neutron diffraction data (taken at the Argonne National Laboratory Intense Pulsed Neutron Source (IPNS) powder diffractometers) at 30-min intervals at 900 and 1,000{degree}C. Previous work has shown that each of these materials (pseudobrookite structure, AB{sub 2}O{sub 5}), (Mn{sub 0.05}Fe{sub 0.33}Ti{sub 0.52})(Ti{sub 2.0})O{sub 5} and (Mg{sub 0.21}Fe{sub 0.33}Ti{sub 0.46})(Ti{sub 1.9}Mg{sub 0.1})O{sub 5}, has a significant amount of Ti in the +3 oxidation state and is completely ordered (no Fe located in the B site). The results of these in situ diffraction studies show that, prior to the thermal decomposition of the slags, there is a redistribution of cations within the pseudobrookite structure.

  18. Ferrous iron uptake by Bifidobacterium bifidum var. pennsylvanicus: the effect of metals and metabolic inhibitors.

    PubMed

    Bezkorovainy, A; Solberg, L; Poch, M; Miller-Catchpole, R

    1987-01-01

    Ferrous iron uptake studies in Bifidobacterium bifidum var. pennsylvanicus were carried out in a well-defined salt solution termed "modified Hanks solution" at both high iron concentrations (LAFIUS conditions) and low concentrations (HAFIUS conditions). Various divalent metals, Mn2+, Zn2+, Ni2+ and Cu2+, inhibited iron uptake under HAFIUS conditions in a non-competitive manner, and in a pseudo-competitive manner under LAFIUS conditions. Cr2+ had no effect. Co2+ inhibited iron uptake competitively under HAFIUS conditions. Metabolic affectors that inhibited iron uptake both under HAFIUS and LAFIUS conditions were: tetraphenylphosphonium chloride, diethylstilbesterol, vanadate, carbonylcyanide-m-chlorophenyl-hydrazone, and a mixture of valinomycin and nigericin. Substances that stimulated iron uptake were KCl, valinomycin, and nigericin. Iron uptake under LAFIUS conditions in piperazine-buffered modified Hanks solution was higher than that in the acetate-buffered solution, and acetate inhibited iron uptake in the piperazine buffer. HAFIUS showed no difference. It is concluded that iron uptake in bifidobacteria is driven by an ATPase-dependent proton-motive force and that both the pH gradient and membrane potential are involved in this process. Mn2+, Zn2+, Ni2+, and Cu2+ may be transported via LAFIUS, but not HAFIUS. HAFIUS may transport only Co2+ in addition to Fe2+. PMID:3038634

  19. Enhanced and stabilized arsenic retention in microcosms through the microbial oxidation of ferrous iron by nitrate.

    PubMed

    Sun, Jing; Chillrud, Steven N; Mailloux, Brian J; Stute, Martin; Singh, Rajesh; Dong, Hailiang; Lepre, Christopher J; Bostick, Benjamin C

    2016-02-01

    Magnetite strongly retains As, and is relatively stable under Fe(III)-reducing conditions common in aquifers that release As. Here, laboratory microcosm experiments were conducted to investigate a potential As remediation method involving magnetite formation, using groundwater and sediments from the Vineland Superfund site. The microcosms were amended with various combinations of nitrate, Fe(II) (aq) (as ferrous sulfate) and lactate, and were incubated for more than 5 weeks. In the microcosms enriched with 10mM nitrate and 5mM Fe(II) (aq), black magnetic particles were produced, and As removal from solution was observed even under sustained Fe(III) reduction stimulated by the addition of 10mM lactate. The enhanced As retention was mainly attributed to co-precipitation within magnetite and adsorption on a mixture of magnetite and ferrihydrite. Sequential chemical extraction, X-ray absorption spectroscopy and magnetic susceptibility measurements showed that these minerals formed at pH 6-7 following nitrate-Fe(II) addition, and As-bearing magnetite was stable under reducing conditions. Scanning electron microscopy and X-ray diffraction indicated that nano-particulate magnetite was produced as coatings on fine sediments, and no aging effect was detected on morphology over the course of incubation. These results suggest that a magnetite based strategy may be a long-term remedial option for As-contaminated aquifers. PMID:26454120

  20. Oxidative precipitation of groundwater-derived ferrous iron in the subterranean estuary of a coastal bay

    NASA Astrophysics Data System (ADS)

    Charette, Matthew A.; Sholkovitz, Edward R.

    2002-05-01

    Sediment cores from the intertidal zone of Waquoit Bay (Cape Cod, Massachusetts) yielded iron oxide-coated sands in the subterranean estuary, which underlies the head of the bay. The oxides were dark red, yellow and orange colors and are formed by the oxidation of ferrous iron-rich groundwater near the groundwater-seawater interface. Within these iron oxide-rich sediments, the concentration of the combined amorphous and crystalline forms of iron oxides ranged between 2500 and 4100 ppm of Fe. These concentrations were 4-6 times greater than the surface sands, and 10-15 times more Fe rich than sands collected from an off-site location. The precipitation of iron oxides in subterranean estuaries could act as a geochemical barrier by retaining and accumulating certain dissolved chemical species carried to the coast by groundwater. Indeed, phosphorus concentrations in the iron oxide-rich sands of Waquoit Bay were 5-7 times greater than the overlying surface sands.

  1. In vitro evaluation of iron solubility and dialyzability of various iron fortificants and of iron-fortified milk products targeted for infants and toddlers.

    PubMed

    Kapsokefalou, Maria; Alexandropoulou, Isidora; Komaitis, Michail; Politis, Ioannis

    2005-06-01

    The objectives of the present study were: to compare the solubility and dialyzability of various iron fortificants (iron pyrophosphate, ferrous bis-glycinate, ferrous gluconate, ferrous lactate, ferrous sulfate) added, in the presence of ascorbic acid, to pasteurized milk samples produced under laboratory conditions; and to compare the solubility and dialyzability of iron in commercial pasteurized, UHT and condensed milk products available in the Greek market fortified with various vitamins and minerals including iron and targeted towards infants (6-12 months old) and toddlers. Iron solubility and dialyzability were determined using a simulated gastrointestinal digestive system. Ferrous dialyzable iron (molecular weight lower than 8000) was used as an index for prediction of iron bioavailability. Ferrous dialyzable iron in pasteurized milk samples fortified with iron pyrophosphate, ferrous lactate and ferrous bis-glycinate was higher (P < 0.05) than that in milk samples fortified with ferrous sulfate and ferrous gluconate. In commercial liquid pasteurized or UHT milk products, formation of ferrous dialyzable iron in products fortified with ferrous lactate was not different (P > 0.05) from those fortified with ferrous sulfate. Ferrous dialyzable iron in four condensed commercial milk products was higher (P < 0.05) than the corresponding values of the liquid UHT milk samples fortified with the same fortificant (ferrous sulfate). Ferrous dialyzable iron was higher (P < 0.05) in products targeted for infants compared with those targeted for toddlers. In conclusion, the type of iron source, milk processing and the overall product composition affect formation of ferrous dialyzable iron and may determine the success and effectiveness of iron fortification of milk. PMID:16096139

  2. Method for separating metal chelates from other materials based on solubilities in supercritical fluids

    DOEpatents

    Wai, Chien M. (Moscow, ID); Smart, Neil G. (Workington, GB); Phelps, Cindy (Moscow, ID)

    2001-01-01

    A method for separating a desired metal or metalloi from impurities using a supercritical extraction process based on solubility differences between the components, as well as the ability to vary the solvent power of the supercritical fluid, is described. The use of adduct-forming agents, such as phosphorous-containing ligands, to separate metal or metalloid chelates in such processes is further disclosed. In preferred embodiments, the extraction solvent is supercritical carbon dioxide and the chelating agent is selected from the group consisting of .beta.-diketones; phosphine oxides, such as trialkylphosphine oxides, triarylphosphine oxides and alkylarylphosphine oxides; phosphinic acids; carboxylic acids; phosphates, such as trialkylphosphates, triarylphosphates and alkylarylphosphates; crown ethers; dithiocarbamates; phosphine sulfides; phosphorothioic acids; thiophosphinic acids; halogenated analogs of these chelating agents; and mixtures of these chelating agents. In especially preferred embodiments, at least one of the chelating agents is fluorinated.

  3. Convection-aided collection of metal ions using chelating porous flat-sheet membranes.

    PubMed

    Saito, Kaori; Saito, Kyoichi; Sugita, Kazuyuki; Tamada, Masao; Sugo, Takanobu

    2002-04-19

    Chelating porous membranes were prepared by radiation-induced graft polymerization of an epoxy-group-containing monomer onto a polyethylene flat sheet and subsequent conversion of the epoxy group to an iminodiacetate group as a chelate-forming group. The chelating group density on the resultant porous flat-sheet membrane of 1.0 mol/kg was comparable to that of commercially available chelating beads. The pure water permeability of the membrane was 40% that of the trunk porous membrane, which was used for microfiltration. During the permeation of a copper chloride solution through the membrane, diffusional mass-transfer resistance of copper ion was negligible, since the ion was transported by convective flow through the pore. The tensile strength and elongation at break of the membranes were measured as a function of dose of electron-beam irradiation, the degree of grafting, and the chelating group density to determine an applicable range for practical use. PMID:12058912

  4. Competitive coordination between lead and oligoelements with respect to some therapeutic heavy-metal chelators

    NASA Astrophysics Data System (ADS)

    Gourlaouen, C.; Parisel, O.

    The competitive complexation of Ca2+, Fe2+, Cu2+, Zn2+, and Pb2+ toward ethylene diamine tetraacetate (EDTA), dimercaprol and D-penicillamine, three liganding agents commonly used in chelation therapy against heavy metal, especially lead, poisonings is examined by means of B3LYP calculations, natural population analyses, and the topological analysis of the electron localization function. It is shown that Pb2+ can displace any of Ca2+, Fe2+, Cu2+, or Zn2+ chelated by any of dimercaprol or D-penicillamine, but can only displace Ca2+ if EDTA is concerned. The first two chelators thus appear as better entities than EDTA to be used in chelation therapy, where in vivo selective complexation is essential. Moreover, the comparison of the bonding characteristics of Pb2+ with those of the other cations allows deriving three features to be taken into account in designing new chelators expecting to have an increased selectivity toward this cation.

  5. Role of pH in metal adsorption from aqueous solutions containing chelating agents on chitosan

    SciTech Connect

    Wu, F.C.; Tseng, R.L.; Juang, R.S.

    1999-01-01

    The role of pH in adsorption of Cu(II) from aqueous solutions containing chelating agents on chitosan was emphasized. Four chelating agents including ethylenediaminetetraacetic acid (EDTA), citric acid, tartaric acid, and sodium gluconate were used. It was shown that the adsorption ability of Cu(II) on chitosan from its chelated solutions varied significantly with pH variations. The competition between coordination of Cu(II) with unprotonated chitosan and electrostatic interaction of the Cu(II) chelates with protonated chitosan took place because of the change in solution pH during adsorption. The maximum adsorption capacity was obtained within each optimal pH range determined from titration curves of the chelated solutions. Coordination of Cu(II) with the unprotonated chitosan was found to dominate at pH below such an optimal pH value.

  6. Advances in transient (pulsed) eddy current for inspection of multi-layer aluminum structures in the presence of ferrous fasteners

    NASA Astrophysics Data System (ADS)

    Desjardins, D. R.; Vallires, G.; Whalen, P. P.; Krause, T. W.

    2012-05-01

    An experimental investigation of the electromagnetic processes underlying transient (pulsed) eddy current inspection of aircraft wing structures in the vicinity of ferrous fasteners is performed. The separate effects of transient excitation of ferrous fastener and eddy currents induced in the surrounding aluminum structure are explored using a transmit-receive configuration with transient excitation of a steel rod, an aluminum plate with a bore hole and a steel rod through the bore hole. Observations are used to interpret results from a coupled driving and differential coil sensing unit applied to detect fatigue cracks emanating from bolt holes in aluminum structures with ferrous fasteners present. In particular, it is noted that abrupt magnetization of the fastener, by the probe's central driving unit, can transfer flux and consequently, induce strong eddy current responses deep within the aluminum structure in the vicinity of the bore hole. Rotation of the probe, centered over the fastener, permits detection of subsurface discontinuities, such as cracks, by the pair of differentially connected pickup coils.

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

    PubMed

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

    2013-03-01

    Iron fortification of foods continues to be one of the preferred ways of improving the iron status of the population. Dairy product is a common product in the diet; therefore, it is a plausible vehicle for iron fortification. This study aims to investigate the bioavailability of ferrous gluconate stabilised with glycine (FGSG) in a fresh cheese fortified with zinc. The iron bioavailability of fresh cheese fortified with either FGSG and with or without zinc and FGSG in aqueous solution and a water solution of ferrous ascorbate (reference dose) was studied using double radio iron ((55)Fe and (59)Fe) erythrocyte incorporation in 15 male subjects. All subjects presented with normal values for iron status parameters. The geometric mean of iron bioavailability for the water solution of FGSG was 38.2 %, adjusted to 40 % from reference doses (N.S.). Iron bioavailability in fresh cheese fortified with Ca and Zn was 15.4 % and was 23.1 % without Zn, adjusted to 40 % from reference doses (N.S.). The results of the present study show that the novel iron compound ferrous gluconate stabilised with glycine in a fresh cheese matrix is a good source of iron and can be used in iron fortification programmes. PMID:23271679

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

    PubMed

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

    2012-12-01

    Non-ferrous metal smelting takes up a large proportion of the anthropogenic mercury emission inventory in China. Zinc, lead and copper smelting are three leading sources. Onsite measurements of mercury emissions were conducted for six smelters. The mercury emission factors were 0.09-2.98 g Hg/t metal produced. Acid plants with the double-conversion double-absorption process had mercury removal efficiency of over 99%. In the flue gas after acid plants, 45-88% was oxidized mercury which can be easily scavenged in the flue gas scrubber. 70-97% of the mercury was removed from the flue gas to the waste water and 1-17% to the sulfuric acid product. Totally 0.3-13.5% of the mercury in the metal concentrate was emitted to the atmosphere. Therefore, acid plants in non-ferrous metal smelters have significant co-benefit on mercury removal, and the mercury emission factors from Chinese non-ferrous metal smelters were probably overestimated in previous studies. PMID:22892573

  9. Control of cytoplasmic calcium with photolabile tetracarboxylate 2-nitrobenzhydrol chelators.

    PubMed Central

    Tsien, R Y; Zucker, R S

    1986-01-01

    This paper introduces nitr-2, a new Ca2+ chelator designed to release Ca2+ upon illumination with near UV (300-400 nm) light. Before illumination nitr-2 has Ca2+ dissociation constants of 160 and 630 nM in 0.1 and 0.3 M ionic strength respectively; after photoconversion to a nitrosobenzophenone the values shift to 7 and 18 microM, high enough to liberate substantial amounts of Ca2+ under intracellular conditions. The speed of release is limited by a dark reaction with rate constant 5 s-1. Aplysia central neurons injected with nitr-2 and exposed to UV light exhibit two separate Ca2+-dependent membrane currents: one carried by potassium ions and one a nonspecific cation current. A quantitative estimate of the spatial distribution of intracellular [Ca2+] changes in large cells filled with a high concentration of nitr-2 and exposed to an intense UV flash is offered. PMID:3098316

  10. Magnetic memory effect in chelated zero valent iron nanoparticles

    NASA Astrophysics Data System (ADS)

    Ghosh, N.; Mandal, B. K.; Mohan Kumar, K.

    2012-11-01

    We report the study of nonequilibrium magnetic behavior of air stable zero valent iron nanoparticles synthesized in presence of N-cetyl-N,N,N-trimethyl ammonium bromide chelating agent. X-ray photoelectron spectroscopy study has suggested the presence of iron oxides on nZVI surfaces. Zero-field-cooled and field-cooled magnetization measurements have been carried out at 20-300 K and 100 Oe. For field-cooled measurements with 1 h stops at 200, 100 and 50 K when compared with the warming cycle, we found the signature of magnetic memory effect. A study of magnetic relaxation at the same temperatures shows the existence of two relaxation times.

  11. Mesoporous organosilica nanotubes containing a chelating ligand in their walls

    SciTech Connect

    Liu, Xiao; Goto, Yasutomo; Maegawa, Yoshifumi; Inagaki, Shinji

    2014-11-01

    We report the synthesis of organosilica nanotubes containing 2,2′-bipyridine chelating ligands within their walls, employing a single-micelle-templating method. These nanotubes have an average pore diameter of 7.8 nm and lengths of several hundred nanometers. UV-vis absorption spectra and scanning transmission electron microscopy observations of immobilized nanotubes with an iridium complex on the bipyridine ligands showed that the 2,2′-bipyridine groups were homogeneously distributed in the benzene-silica walls. The iridium complex, thus, immobilized on the nanotubes exhibited efficient catalytic activity for water oxidation using Ce{sup 4+}, due to the ready access of reactants to the active sites in the nanotubes.

  12. Clinically Approved Iron Chelators Influence Zebrafish Mortality, Hatching Morphology and Cardiac Function

    PubMed Central

    Hamilton, Jasmine L.; Hatef, Azadeh; Imran ul-haq, Muhammad; Nair, Neelima; Unniappan, Suraj; Kizhakkedathu, Jayachandran N.

    2014-01-01

    Iron chelation therapy using iron (III) specific chelators such as desferrioxamine (DFO, Desferal), deferasirox (Exjade or ICL-670), and deferiprone (Ferriprox or L1) are the current standard of care for the treatment of iron overload. Although each chelator is capable of promoting some degree of iron excretion, these chelators are also associated with a wide range of well documented toxicities. However, there is currently very limited data available on their effects in developing embryos. In this study, we took advantage of the rapid development and transparency of the zebrafish embryo, Danio rerio to assess and compare the toxicity of iron chelators. All three iron chelators described above were delivered to zebrafish embryos by direct soaking and their effects on mortality, hatching and developmental morphology were monitored for 96 hpf. To determine whether toxicity was specific to embryos, we examined the effects of chelator exposure via intra peritoneal injection on the cardiac function and gene expression in adult zebrafish. Chelators varied significantly in their effects on embryo mortality, hatching and morphology. While none of the embryos or adults exposed to DFO were negatively affected, ICL -treated embryos and adults differed significantly from controls, and L1 exerted toxic effects in embryos alone. ICL-670 significantly increased the mortality of embryos treated with doses of 0.25 mM or higher and also affected embryo morphology, causing curvature of larvae treated with concentrations above 0.5 mM. ICL-670 exposure (10 µL of 0.1 mM injection) also significantly increased the heart rate and cardiac output of adult zebrafish. While L1 exposure did not cause toxicity in adults, it did cause morphological defects in embryos at 0.5 mM. This study provides first evidence on iron chelator toxicity in early development and will help to guide our approach on better understanding the mechanism of iron chelator toxicity. PMID:25329065

  13. A new approach to bifunctional chelate attachment to antibodies

    SciTech Connect

    Wang, T.S.T.; Rosen, J.M.; Smith, R.; Fawwaz, R.A.; Ferrone, S.; Alderson, P.O.

    1984-01-01

    One potential problem with the synthesis of bifunctional chelates (BC) of antibodies (Abs) is inactivation of the Ab by attachment of the chelate (C) at or near the antigen (Ag) binding site. The most common method of synthesizing BC depends on attachment of a C (e.g., DTPA) to a free amino group on the Ab molecule. However, the Ab may be inactivated if this amino group is too near the Ag binding site. We examined an alternative method, with attachment of a C, desferrioxamine-B(DF), to free carboxyl groups of Ab molecules. BC of a monoclonal Ab to a melanoma-associated Ag were prepared using DF, and labeled with In-111. DF-Ab was prepared by mixing Ab, DF, and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide at pH 4.75. BC of the same Ab also were prepared, using DTPA, by the cyclic anhydride method (DTPA-Ab). Good radiolabeling yields were achieved with both DF-Ab and DTPA-Ab. The reactivity of DF-Ab and DTPA-Ab with melanoma Ag was treated in vitro. Binding of the Ab to melanoma cells and to control (lymphoma) cells was assayed. DF-Ab and DTPA-Ab demonstrated significant cell binding (61.5 and 38.2% respectively, at appropriate dilutions) when tested with melanoma cells. Neither Ab bound significantly to control cells (6.9 and 3.3% respectively). These experiments demonstrate that BC of Abs can be successfully prepared by binding C to free carboxyl groups on Abs. The DF-Ab so produced demonstrates significant reactivity with its Ag. With some Abs, as with the above anti-melanoma Ab, this method of BC preparation may result in less loss of antigenic reactivity than occurs with conventional methods.

  14. Spin-Spin Relaxation Rate MRI Dosimetry Using Ferrous Sulphate Gelatin Materials.

    NASA Astrophysics Data System (ADS)

    Duzenli, Cheryl Rose

    1995-01-01

    Recent developments in conformal radiotherapy involving non-standard geometries and time dependent radiation beam configurations, have increased the challenge to provide accurate dosimetry. Existing methods of dose measurement in the clinical setting fall short of fulfilling the need for a volumetric, tissue equivalent, integrating dosimeter to cover the range of clinical applications now available. The volumetric requirement provides for realistic anatomical representation of the patient; tissue equivalence ensures accurate determination of absorbed dose by tissue; and integration provides for the measurement of non-stationary radiotherapy beams. In this thesis the dosimetry problem is addressed in terms of a measurement technique that merges chemical dosimetry with nuclear magnetic resonance (NMR) and imaging in an attempt to fulfill the above criteria. A general discussion of the dosimetry of ionizing radiation is followed by a summary of the NMR relaxation theory and radiation chemistry required to understand the dosimeter response. Acquisition of accurate relaxation rate data in the spectrometer and imaging settings is discussed. A wide-ranging study of NMR spin-spin relaxation rate (R2) in the ferrous sulphate gelatin dosimeter system is presented. This includes an investigation of the frequency dependence of both R2 and spin-lattice relaxation rate (R1) in aqueous solutions containing ferrous or ferric ions. Also explored are the effects of acid and gelling agent concentrations on the R2 response of the dosimeter material, and on diffusion of ferric ions within the material. The effects of benzoic acid, of spontaneous oxidation, and of temperature on the dosimeter are also explored. Correction techniques for R2 distortion in the imaging setting are discussed. A novel method of producing accurate distributions of changes in R2 (Delta R2) to reflect absorbed dose is demonstrated. This method, termed the echo quotient technique, is then applied to external electron beam dosimetry, dynamic external photon beam dosimetry and high dose rate (HDR) brachytherapy dosimetry. The dosimetric quality of the Delta R2 image data is discussed and compared with film, diode and ion chamber data. Finally, a summary and conclusions regarding the viability of the technique include the following: (1) measuring Delta R2 at the highest available imaging frequency provides the best sensitivity to dose, (2) a standard dosimeter composition providing the best compromise between good sensitivity to dose and reduction of ion diffusion rates has been determined to be 4% gelatin by weight, 0.05 rm MH_2SO_4 and 1 mM FeSO_4, (3) O _2 depletion effects are significant but can be avoided, (4) maintaining a constant phantom temperature during the imaging process is important, (5) gelatin is inferior to agarose as a gelling agent in terms of both dosimeter sensitivity enhancement and reduction of ion diffusion rate, and (6) the echo quotient technique allows dose distributions to be measured in extended phantoms to an accuracy of +/-1 Gy with a spatial resolution of 1 mm x 1 mm x 5 mm.

  15. Effects of iron glycine chelate on growth, tissue mineral concentrations, fecal mineral excretion, and liver antioxidant enzyme activities in broilers.

    PubMed

    Ma, W Q; Sun, H; Zhou, Y; Wu, J; Feng, J

    2012-11-01

    The study was conducted to determine the effects of iron glycine chelate (Fe-Gly) on growth, tissue mineral concentrations, fecal mineral excretion, and liver antioxidant enzyme activities in broilers. A total of 360 1-day-old commercial broilers (Ross Ross) were randomly allotted to six dietary treatments with six replications of ten chicks per replicate. Broilers were fed a control diet with no Fe supplementation, while five other treatments consisted of 40, 80, 120, and 160 mg Fe/kg diets from Fe-Gly, and 160 mg Fe/kg from ferrous sulfate, respectively. After a 42-day feeding trial, the results showed that 120 and 160 mg Fe/kg as Fe-Gly improved the average daily gain (P < 0.05) and average daily feed intake (P < 0.05) of broilers (4-6 weeks). Addition with 120 and 160 mg Fe/kg from Fe-Gly and 160 mg Fe/kg from FeSO(4) increased Fe concentration in serum (P < 0.05), liver (P < 0.05), breast muscle (P < 0.05), tibia (P < 0.05), and feces (P < 0.01) at 21 and 42 days. There were linear responses to the addition of Fe-Gly from 0 to 160 mg/kg Fe on Fe concentration in serum (21 days, P = 0.005; 42 days, P = 0.001), liver (P = 0.001), breast muscle (P = 0.001), tibia (P = 0.001), and feces (21 days, P = 0.011; 42 days, P = 0.032). Liver Cu/Zn superoxide dismutase activities of chicks were increased by the addition of 80, 120, and 160 mg Fe/kg as Fe-Gly to diets at 42 days. There were no differences in liver catalase activities of chicks among the treatments (P > 0.05). This study indicates that addition with Fe-Gly could improve growth performance and iron tissue storage and improves the antioxidant status of broiler chickens. PMID:22549700

  16. Computational methods for intramolecular electron transfer in a ferrous-ferric iron complex.

    PubMed

    Zarzycki, Piotr; Kerisit, Sebastien; Rosso, Kevin

    2011-09-01

    The limitations of common theoretical and molecular computational approaches for predicting electron transfer quantities were assessed, using an archetypal bridged ferrous-ferric electron transfer system in aqueous solution. The basis set effect on the magnitude of the electronic coupling matrix element computed using the quasi-diabatic method was carefully examined, and it was found that the error related to a poor basis set could exceed the thermal energy at room temperature. A range of approaches to determining the external (solvent) reorganization energy were also investigated. Significant improvements from the Marcus continuum model can be obtained by including dipolar Born-Kirkwood-Onsager correction. In this regard, we also found that Klamt's Conductor-Like Screening Model (COSMO) yields estimations of the external reorganization energy similar to those obtained with explicit solvent molecular dynamics simulations if the fast-frequency modes are neglected, which makes it an attractive alternative to laborious umbrella sampling simulations. By using the COSMO model, we also confirm that a decrease in curvature of the potential energy surface is a manifestation of the dielectric saturation observed in the first solvation layer. The linearity of solvent response to the charge redistribution was assessed by analyzing the energy gap autocorrelation function as well as the solvent density and dipole moment fluctuations. Molecular dynamics was also used to evaluate the sign and magnitude of the solvent reorganization entropy and to determine its effect on the predicted electron transfer rate. Finally, we present a simple way of estimating the vibration frequency along the reaction coordinate, which also enables prediction of the mass-dependent isotopic signature of electron transfer reactions. PMID:21696749

  17. A Ferrous Iron Exporter Mediates Iron Resistance in Shewanella oneidensis MR-1.

    PubMed

    Bennett, Brittany D; Brutinel, Evan D; Gralnick, Jeffrey A

    2015-11-01

    Shewanella oneidensis strain MR-1 is a dissimilatory metal-reducing bacterium frequently found in aquatic sediments. In the absence of oxygen, S. oneidensis can respire extracellular, insoluble oxidized metals, such as iron (hydr)oxides, making it intimately involved in environmental metal and nutrient cycling. The reduction of ferric iron (Fe(3+)) results in the production of ferrous iron (Fe(2+)) ions, which remain soluble under certain conditions and are toxic to cells at higher concentrations. We have identified an inner membrane protein in S. oneidensis, encoded by the gene SO_4475 and here called FeoE, which is important for survival during anaerobic iron respiration. FeoE, a member of the cation diffusion facilitator (CDF) protein family, functions to export excess Fe(2+) from the MR-1 cytoplasm. Mutants lacking feoE exhibit an increased sensitivity to Fe(2+). The export function of FeoE is specific for Fe(2+), as an feoE mutant is equally sensitive to other metal ions known to be substrates of other CDF proteins (Cd(2+), Co(2+), Cu(2+), Mn(2+), Ni(2+), or Zn(2+)). The substrate specificity of FeoE differs from that of FieF, the Escherichia coli homolog of FeoE, which has been reported to be a Cd(2+)/Zn(2+) or Fe(2+)/Zn(2+) exporter. A complemented feoE mutant has an increased growth rate in the presence of excess Fe(2+) compared to that of the ΔfeoE mutant complemented with fieF. It is possible that FeoE has evolved to become an efficient and specific Fe(2+) exporter in response to the high levels of iron often present in the types of environmental niches in which Shewanella species can be found. PMID:26341213

  18. Structural analysis of metastable pseudobrookite ferrous titanium oxides with neutron diffraction and Mossbauer spectroscopy

    SciTech Connect

    Teller, R.G.; Antonio, M.R. ); Grau, A.E.; Gueguin, M. ); Kostiner, E. )

    1990-10-01

    Four synthetic iron titanium oxides with the pseudobrookite (AB{sub 2}O{sub 5}, Cmcm, Z = 4) structure have been prepared and characterized by neutron diffraction and zero-field, natural abundance {sup 57}Fe Mossbauer effect spectroscopy (MES). The combination of the element specificity of MES with the different neutron scattering lengths of Ti and Fe ({minus}0.33 and 0.95 {times} 10{sup {minus}12} cm, respectively) offers a unique opportunity to distinguish between cation distributions on the two (A and B) sites. Two of the samples have been prepared in low temperature experiments (quenched from 1,200{degree}C) and have the stoichiometry FeTi{sub 2}O{sub 5}, and Fe{sub .6}Mg{sub .6}Ti{sub 1.8}O{sub 5}. The third and fourth samples are commercial iron titanium oxides prepared by the reduction of ilmenite ore with carbon above 1,700{degree}C. The stoichiometries of these samples are Mn{sub 0.05}Fe{sub 0.33}Ti{sub 2.52}O{sub 5} and Fe{sub .33}Mg{sub .31}Ti{sub 2.36}O{sub 5}. Results from these experiments indicate that for each of these samples the B site is predominantly (> 65%) occupied by Ti, while the A site contains a mixture of Ti, Fe, and/or Mg. However, only at higher temperatures (> 1,700{degree}C) is the B site devoid of ferrous cations.

  19. A novel approach to oral iron delivery using ferrous sulphate loaded solid lipid nanoparticles.

    PubMed

    Zariwala, M Gulrez; Elsaid, Naba; Jackson, Timothy L; Corral Lpez, Francisco; Farnaud, Sebastien; Somavarapu, Satyanarayana; Renshaw, Derek

    2013-11-18

    Iron (Fe) loaded solid lipid nanoparticles (SLN's) were formulated using stearic acid and iron absorption was evaluated in vitro using the cell line Caco-2 with intracellular ferritin formation as a marker of iron absorption. Iron loading was optimised at 1% Fe (w/w) lipid since an inverse relation was observed between initial iron concentration and SLN iron incorporation efficiency. Chitosan (Chi) was included to prepare chitosan coated SLN's. Particle size analysis revealed a sub-micron size range (300.331.75 nm to 495.180.42 nm), with chitosan containing particles having the largest dimensions. As expected, chitosan (0.1%, 0.2% and 0.4% w/v) conferred a net positive charge on the particle surface in a concentration dependent manner. For iron absorption experiments equal doses of Fe (20 ?M) from selected formulations (SLN-FeA and SLN-Fe-ChiB) were added to Caco-2 cells and intracellular ferritin protein concentrations determined. Caco-2 iron absorption from SLN-FeA (583.9840.83 ng/mg cell protein) and chitosan containing SLN-Fe-ChiB (642.7729.37 ng/mg cell protein) were 13.42% and 24.9% greater than that from ferrous sulphate (FeSO4) reference (514.6620.43 ng/mg cell protein) (p?0.05). We demonstrate for the first time preparation, characterisation and superior iron absorption in vitro from SLN's, suggesting the potential of these formulations as a novel system for oral iron delivery. PMID:24012860

  20. Statistical Analysis of Metal Chelating Activity of Centella asiatica and Erythroxylum cuneatum Using Response Surface Methodology.

    PubMed

    Mohd Salim, R J; Adenan, M I; Amid, A; Jauri, M H; Sued, A S

    2013-01-01

    The purpose of the study is to evaluate the relationship between the extraction parameters and the metal chelating activity of Centella asiatica (CA) and Erythroxylum cuneatum (EC). The response surface methodology was used to optimize the extraction parameters of methanolic extract of CA and EC with respect to the metal chelating activity. For CA, Run 17 gave optimum chelating activity with IC50 = 0.93?mg/mL at an extraction temperature of 25C, speed of agitation at 200?rpm, ratio of plant material to solvent at 1?g?:?45?mL and extraction time at 1.5 hour. As for EC, Run 13 with 60C, 200?rpm, 1?g?:?35?mL and 1 hour had metal chelating activity at IC50 = 0.3817?mg/mL. Both optimized extracts were further partitioned using a solvent system to evaluate the fraction responsible for the chelating activity of the plants. The hexane fraction of CA showed potential activity with chelating activity at IC50 = 0.090 and the ethyl acetate fraction of EC had IC50 = 0.120?mg/mL. The study showed that the response surface methodology helped to reduce the extraction time, temperature and agitation and subsequently improve the chelating activity of the plants in comparison to the conventional method. PMID:23533781

  1. Chelating capture and magnetic removal of non-magnetic heavy metal substances from soil

    PubMed Central

    Fan, Liren; Song, Jiqing; Bai, Wenbo; Wang, Shengping; Zeng, Ming; Li, Xiaoming; Zhou, Yang; Li, Haifeng; Lu, Haiwei

    2016-01-01

    A soil remediation method based on magnetic beneficiation is reported. A new magnetic solid chelator powder, FS@IDA (core-shell Fe3O4@SiO2 nanoparticles coated with iminodiacetic acid chelators), was used as a reactive magnetic carrier to selectively capture non-magnetic heavy metals in soil by chelation and removal by magnetic separation. FS@IDA was prepared via inorganic-organic and organic synthesis reactions that generated chelating groups on the surface of magnetic, multi-core, core-shell Fe3O4@SiO2 (FS) nanoparticles. These reactions used a silane coupling agent and sodium chloroacetate. The results show that FS@IDA could chelate the heavy metal component of Cd, Zn, Pb, Cu and Ni carbonates, lead sulfate and lead chloride in water-insoluble salt systems. The resulting FS@IDA-Cd and FS@IDA-Pb chelates could be magnetically separated, resulting in removal rates of approximately 84.9% and 72.2% for Cd and Pb, respectively. FS@IDA could not remove the residual heavy metals and those bound to organic matter in the soil. FS@IDA did not significantly alter the chemical composition of the soil, and it allowed for fast chelating capture, simple magnetic separation and facilitated heavy metal elution. FS@IDA could also be easily prepared and reprocessed. PMID:26878770

  2. Effects of calcium chelators on calcium distribution and protein solubility in rennet casein dispersions.

    PubMed

    McIntyre, Irene; O' Sullivan, Michael; O' Riordan, Dolores

    2016-04-15

    This study investigated the effects of calcium chelating salts on calcium-ion activity (ACa(++)), calcium distribution, and protein solubility in model CaCl2 solutions (50 mmol L(-1)) or rennet casein dispersions (15 g/100 g). Disodium phosphate and trisodium citrate at concentrations of 10 and 30 mmol L(-1) and at ratios of 1:0, 2:1, 1:1, 1:2 and 0:1 were added to both systems. The CaCl2 system, despite its simplicity, was a good indicator of chelating salt-calcium interactions in rennet casein dispersions. Adding trisodium citrate either alone or as part of a mixed chelating salt system resulted in high levels of dispersed "chelated" calcium; conversely, disodium phosphate addition resulted in lower levels, while the ACa(++) decreased with increasing concentration of both chelating salts. Neither chelating salt produced high levels of soluble protein. Thus calcium chelating salts may play a more subtle role in modulating hydration during manufacture of casein-based matrices than simply solubilising calcium or protein. PMID:26616945

  3. Chelating capture and magnetic removal of non-magnetic heavy metal substances from soil.

    PubMed

    Fan, Liren; Song, Jiqing; Bai, Wenbo; Wang, Shengping; Zeng, Ming; Li, Xiaoming; Zhou, Yang; Li, Haifeng; Lu, Haiwei

    2016-01-01

    A soil remediation method based on magnetic beneficiation is reported. A new magnetic solid chelator powder, FS@IDA (core-shell Fe3O4@SiO2 nanoparticles coated with iminodiacetic acid chelators), was used as a reactive magnetic carrier to selectively capture non-magnetic heavy metals in soil by chelation and removal by magnetic separation. FS@IDA was prepared via inorganic-organic and organic synthesis reactions that generated chelating groups on the surface of magnetic, multi-core, core-shell Fe3O4@SiO2 (FS) nanoparticles. These reactions used a silane coupling agent and sodium chloroacetate. The results show that FS@IDA could chelate the heavy metal component of Cd, Zn, Pb, Cu and Ni carbonates, lead sulfate and lead chloride in water-insoluble salt systems. The resulting FS@IDA-Cd and FS@IDA-Pb chelates could be magnetically separated, resulting in removal rates of approximately 84.9% and 72.2% for Cd and Pb, respectively. FS@IDA could not remove the residual heavy metals and those bound to organic matter in the soil. FS@IDA did not significantly alter the chemical composition of the soil, and it allowed for fast chelating capture, simple magnetic separation and facilitated heavy metal elution. FS@IDA could also be easily prepared and reprocessed. PMID:26878770

  4. Function of the iron-binding chelator produced by Coriolus versicolor in lignin biodegradation.

    PubMed

    Wang, Lu; Yan, WenChao; Chen, JiaChuan; Huang, Feng; Gao, PeiJi

    2008-03-01

    An ultrafiltered low-molecular-weight preparation of chelating compounds was isolated from a wood-containing culture of the white-rot basidiomycete Coriolus versicolor. This preparation could chelate Fe3+ and reduce Fe3+ to Fe2+, demonstrating that the substance may serve as a ferric chelator, oxygen-reducing agent, and redox-cycling molecule, which would include functioning as the electron transport carrier in Fenton reaction. Lignin was treated with the iron-binding chelator and the changes in structure were investigated by 1H-NMR, 13C-NMR, difference spectrum caused by ionization under alkaline conditions and nitrobenzene oxidation. The results indicated that the iron-binding chelator could destroy the beta-O-4 bonds in etherified lignin units and insert phenolic hydroxyl groups. The low-molecular-weight chelator secreted by C. versicolor resulted in new phenolic substructures in the lignin polymer, making it susceptible to attack by laccase or manganese peroxidase. Thus, the synergic action of the iron-binding chelator and the lignocellulolytic enzymes made the substrate more accessible to degradation. PMID:18246309

  5. Chelating capture and magnetic removal of non-magnetic heavy metal substances from soil

    NASA Astrophysics Data System (ADS)

    Fan, Liren; Song, Jiqing; Bai, Wenbo; Wang, Shengping; Zeng, Ming; Li, Xiaoming; Zhou, Yang; Li, Haifeng; Lu, Haiwei

    2016-02-01

    A soil remediation method based on magnetic beneficiation is reported. A new magnetic solid chelator powder, FS@IDA (core-shell Fe3O4@SiO2 nanoparticles coated with iminodiacetic acid chelators), was used as a reactive magnetic carrier to selectively capture non-magnetic heavy metals in soil by chelation and removal by magnetic separation. FS@IDA was prepared via inorganic-organic and organic synthesis reactions that generated chelating groups on the surface of magnetic, multi-core, core-shell Fe3O4@SiO2 (FS) nanoparticles. These reactions used a silane coupling agent and sodium chloroacetate. The results show that FS@IDA could chelate the heavy metal component of Cd, Zn, Pb, Cu and Ni carbonates, lead sulfate and lead chloride in water-insoluble salt systems. The resulting FS@IDA-Cd and FS@IDA-Pb chelates could be magnetically separated, resulting in removal rates of approximately 84.9% and 72.2% for Cd and Pb, respectively. FS@IDA could not remove the residual heavy metals and those bound to organic matter in the soil. FS@IDA did not significantly alter the chemical composition of the soil, and it allowed for fast chelating capture, simple magnetic separation and facilitated heavy metal elution. FS@IDA could also be easily prepared and reprocessed.

  6. Fabrication and characterization of the nano-composite of whey protein hydrolysate chelated with calcium.

    PubMed

    Xixi, Cai; Lina, Zhao; Shaoyun, Wang; Pingfan, Rao

    2015-03-01

    The nano-composites of whey protein hydrolysate (WPH) chelated with calcium were fabricated in aqueous solution at 30 °C for 20 min, with the ratio of hydrolysate to calcium 15 : 1 (w/w). UV scanning spectroscopy, fluorescent spectroscopy, Fourier transform infrared spectroscopy, dynamic light scattering and atomic force microscopy were applied to characterize the structure of the WPH-calcium chelate. The nano-composites showed the successful incorporation of calcium into the WPH, indicating the interaction between calcium and WPH. The chelation of calcium ions to WPH caused molecular folding and aggregation which led to the formation of a WPH-calcium chelate of nanoparticle size, and the principal sites of calcium-binding corresponded to the carboxyl groups and carbonyl groups of WPH. The WPH-calcium chelate demonstrated excellent stability and absorbability under both acidic and basic conditions, which was beneficial for calcium absorption in the gastrointestinal tract of the human body. Moreover, the calcium absorption of the WPH-calcium chelate on Caco-2 cells was significantly higher than those of calcium gluconate and CaCl₂ in vitro, suggesting the possible increase in calcium bioavailability. The findings suggest that the WPH-calcium chelate has the potential in making dietary supplements for improving bone health of the human body. PMID:25588126

  7. Generation, Fractionation, and Characterization of Iron-Chelating Protein Hydrolysate from Palm Kernel Cake Proteins.

    PubMed

    Zarei, Mohammad; Ghanbari, Rahele; Tajabadi, Naser; Abdul-Hamid, Azizah; Bakar, Fatimah Abu; Saari, Nazamid

    2016-02-01

    Palm kernel cake protein was hydrolyzed with different proteases namely papain, bromelain, subtilisin, flavourzyme, trypsin, chymotrypsin, and pepsin to generate different protein hydrolysates. Peptide content and iron-chelating activity of each hydrolysate were evaluated using O-phthaldialdehyde-based spectrophotometric method and ferrozine-based colorimetric assay, respectively. The results revealed a positive correlation between peptide contents and iron-chelating activities of the protein hydrolysates. Protein hydrolysate generated by papain exhibited the highest peptide content of 10.5 mM and highest iron-chelating activity of 64.8% compared with the other hydrolysates. Profiling of the papain-generated hydrolysate by reverse phase high performance liquid chromatography fractionation indicated a direct association between peptide content and iron-chelating activity in most of the fractions. Further fractionation using isoelectric focusing also revealed that protein hydrolysate with basic and neutral isoelectric point (pI) had the highest iron-chelating activity, although a few fractions in the acidic range also exhibited good metal chelating potential. After identification and synthesis of papain-generated peptides, GGIF and YLLLK showed among the highest iron-chelating activities of 56% and 53%, whereas their IC50 were 1.4 and 0.2 μM, respectively. PMID:26720491

  8. Synthesis of novel bifunctional chelators and their use in preparing monoclonal antibody conjugates for tumor targeting

    SciTech Connect

    Westerberg, D.A.; Carney, P.L.; Rogers, P.E.; Kline, S.J.; Johnson, D.K.

    1989-01-01

    Bifunctional derivatives of the chelating agents ethylenediaminetetraacetic acid and diethylenetriaminepentaacetic acid, in which a p-isothiocyanatobenzyl moiety is attached at the methylene carbon atom of one carboxymethyl arm, was synthesized by reductive alkylation of the relevant polyamine with (p-nitrophenyl)pyruvic acid followed by carboxymethylation, reduction of the nitro group, and reaction with thiophosgene. The resulting isothiocyanate derivatives reacted with monoclonal antibody B72.3 to give antibody-chelator conjugates containing 3 mol of chelator per mole of immunoglobulin, without significant loss of immunological activity. Such conjugates, labeled with the radioisotopic metal indium-111, selectively bound a human colorectal carcinoma implanted in nude mice when given intravenously. Uptake into normal tissues was comparable to or lower than that reported for analogous conjugates with known bifunctional chelators. It is concluded that substitution with a protein reactive group at this position in polyaminopolycarboxylate chelators does not alter the chelating properties of these molecules to a sufficient extent to adversely affect biodistribution and thus provides a general method for the synthesis of such chelators.

  9. Statistical Analysis of Metal Chelating Activity of Centella asiatica and Erythroxylum cuneatum Using Response Surface Methodology

    PubMed Central

    Mohd Salim, R. J.; Adenan, M. I.; Amid, A.; Jauri, M. H.; Sued, A. S.

    2013-01-01

    The purpose of the study is to evaluate the relationship between the extraction parameters and the metal chelating activity of Centella asiatica (CA) and Erythroxylum cuneatum (EC). The response surface methodology was used to optimize the extraction parameters of methanolic extract of CA and EC with respect to the metal chelating activity. For CA, Run 17 gave optimum chelating activity with IC50 = 0.93?mg/mL at an extraction temperature of 25C, speed of agitation at 200?rpm, ratio of plant material to solvent at 1?g?:?45?mL and extraction time at 1.5 hour. As for EC, Run 13 with 60C, 200?rpm, 1?g?:?35?mL and 1 hour had metal chelating activity at IC50 = 0.3817?mg/mL. Both optimized extracts were further partitioned using a solvent system to evaluate the fraction responsible for the chelating activity of the plants. The hexane fraction of CA showed potential activity with chelating activity at IC50 = 0.090 and the ethyl acetate fraction of EC had IC50 = 0.120?mg/mL. The study showed that the response surface methodology helped to reduce the extraction time, temperature and agitation and subsequently improve the chelating activity of the plants in comparison to the conventional method. PMID:23533781

  10. Alteration of tissue disposition of cadmium by chelating agents. [Mice; rats

    SciTech Connect

    Klaassen, C.D.; Waalkes, M.P.; Cantilena, L.R. Jr.

    1984-03-01

    The effect of several chelating agents (diethyldithiocarbamic acid, DDC; nitrilotriacetic acid, NTA; 2,3-dimercaptopropanol, BAL; d,l-penicillamine, PEN; 2,3-dimercaptosuccinic acid, DMSA; ethylenediaminetetraacetic acid, EDTA; and diethylenetriaminepentaacetic acid, DTPA) on the toxicity, distribution and excretion of cadmium (Cd) was determined in mice. When chelators were administered immediately after Cd, significant increases in survival were noted after treatment with DMSA, EDTA, and DTPA. DTPA, followed by EDTA and then DMSA, were consistently the most effective in decreasing the tissue concentrations of Cd and increasing the excretion of Cd. NTA, BAL, DDC and PEN had no beneficial effects. To determine the role of MT in the acute decrease in chelator efficacy following Cd poisoning, rats were injected IV with Cd followed by DTPA at various times after Cd. Although DTPA reduced Cd content in the various organs when given immediately after Cd, the chelator was ineffective at all later times. Increases in hepatic and renal metallothionein (MT) did not occur until 2 hr after Cd, and did not coincide with the earlier drop in chelator efficacy. Blockade of MT synthesis by actinomycin D failed to eliminate this decreased DTPA effectiveness. Therefore, it appears that MT does not play an important role in the acute decrease in efficacy of chelation therapy for Cd poisoning. The effect of repeated daily administration of chelators on the distribution and excretion of Cd was studied by administering chelators daily for 5 days starting 48 hr after Cd. DTPA, EDTA, DMSA and BAL significantly increased the urinary elimination of Cd. Thus, mobilization of Cd into urine occurs with repeated chelation therapy, which may decrease tissue concentrations of Cd and reduce the toxicity of the metal. 4 references, 15 figures, 2 tables.

  11. Chelate effects in sulfate binding by amide/urea-based ligands.

    PubMed

    Jia, Chuandong; Wang, Qi-Qiang; Begum, Rowshan Ara; Day, Victor W; Bowman-James, Kristin

    2015-07-01

    The influence of chelate and mini-chelate effects on sulfate binding was explored for six amide-, amide/amine-, urea-, and urea/amine-based ligands. Two of the urea-based hosts were selective for SO4(2-) in water-mixed DMSO-d6 systems. Results indicated that the mini-chelate effect provided by a single urea group with two NH binding sites appears to provide enhanced binding over two amide groups. Furthermore, additional urea binding sites incorporated into the host framework appeared to overcome to some extent competing hydration effects with increasing water content. PMID:25966663

  12. (Bifunctional chelates of Rh-105, Au-199, and other metallic radionuclides as potential radiotherapeutic agents)

    SciTech Connect

    Not Available

    1991-01-01

    Progress during this period is reported under the following headings: Diethylenetriamine based and related bifunctional chelating agents and their complexation with Rh-105, Au-198, Pd-109, cu-67, In-111, and Co-57; studies of Pd-109, Rh-105 and Tc-99m with bifunctional chelates based on phenylenediamine; establishment of an appropriate protein assay method for conjugated proteins; studies of new bifunctional Bi, Tri and tetradentate amine oxime ligands with Rh-105; IgG and antibody B72.3 conjugation studies by HPLC Techniques with bifunctional metal chelates; and progress on ligand systems for Au(III).

  13. [Bifunctional chelates of Rh-105, Au-199, and other metallic radionuclides as potential radiotherapeutic agents

    SciTech Connect

    Not Available

    1991-12-31

    Progress during this period is reported under the following headings: Diethylenetriamine based and related bifunctional chelating agents and their complexation with Rh-105, Au-198, Pd-109, cu-67, In-111, and Co-57; studies of Pd-109, Rh-105 and Tc-99m with bifunctional chelates based on phenylenediamine; establishment of an appropriate protein assay method for conjugated proteins; studies of new bifunctional Bi, Tri and tetradentate amine oxime ligands with Rh-105; IgG and antibody B72.3 conjugation studies by HPLC Techniques with bifunctional metal chelates; and progress on ligand systems for Au(III).

  14. Design, synthesis, and evaluation of polyhydroxamate chelators for selective complexation of actinides

    SciTech Connect

    Gopalan, A.; Jacobs, H.; Koshti, N.; Stark, P.; Huber, V.; Dasaradhi, L.; Caswell, W.; Smith, P.; Jarvinen, G.

    1995-08-01

    Specific chelating polymers targeted for actinides have much relevance to problems involving remediation of nuclear waste. Goal is to develop polymer supported, ion specific extraction systems for removing actinides and other hazardous metal ions from wastewaters. This is part of an effort to develop chelators for removing actinide ions such as Pu from soils and waste streams. Selected ligands are being attached to polymeric backbones to create novel chelating polymers. These polymers and other water soluble and insoluble polymers have been synthesized and are being evaluated for ability to selectively remove target metal ions from process waste streams.

  15. River-derived humic substances as iron chelators in seawater

    PubMed Central

    Krachler, Regina; Krachler, Rudolf F.; Wallner, Gabriele; Hann, Stephan; Laux, Monika; Cervantes Recalde, Maria F.; Jirsa, Franz; Neubauer, Elisabeth; von der Kammer, Frank; Hofmann, Thilo; Keppler, Bernhard K.

    2015-01-01

    The speciation of iron(III) in oxic seawater is dominated by its hydrolysis and sedimentation of insoluble iron(III)-oxyhydroxide. As a consequence, many oceanic areas have very low iron levels in surface seawater which leads to iron deficiency since phytoplankton require iron as a micronutrient in order to grow. Fortunately, iron solubility is not truly as low as Fe(III) solubility measurements in inorganic seawater would suggest, since oceanic waters contain organic molecules which tend to bind the iron and keep it in solution. Various iron-binding organic ligands which combine to stabilize dissolved iron have been detected and thoroughly investigated in recent years. However, the role of iron-binding ligands from terrestrial sources remains poorly constrained. Blackwater rivers supply large amounts of natural organic material (NOM) to the ocean. This NOM (which consists mainly of vascular plant-derived humic substances) is able to greatly enhance iron bioavailability in estuaries and coastal regions, however, breakdown processes lead to a rapid decrease of river-derived NOM concentrations with increasing distance from land. It has therefore been argued that the influence of river-derived NOM on iron biogeochemistry in offshore seawater does not seem to be significant. Here we used a standard method based on 59Fe as a radiotracer to study the solubility of Fe(III)-oxyhydroxide in seawater in the presence of riverine NOM. We aimed to address the question how effective is freshwater NOM as an iron chelator under open ocean conditions where the concentration of land-derived organic material is about 3 orders of magnitude smaller than in coastal regions, and does this iron chelating ability vary between NOM from different sources and between different size fractions of the river-borne NOM. Our results show that the investigated NOM fractions were able to substantially enhance Fe(III)-oxyhydroxide solubility in seawater at concentrations of the NOM ≥ 5 μg L− 1. Terrigenous NOM concentrations ≥ 5 μg L− 1 are in no way unusual in open ocean surface waters especially of the Arctic and the North Atlantic Oceans. River-derived humic substances could therefore play a greater role as iron carriers in the ocean than previously thought. PMID:26412934

  16. Radiolabeled technetium chelates for use in renal function determinations

    DOEpatents

    Fritzberg, Alan (Edmonds, WA); Kasina, Sudhaker (Kirkland, WA); Johnson, Dennis L. (Las Cruces, NM)

    1994-01-01

    The present invention is directed to novel radiopharmaceutical imaging agents incorporating Tc-99m as a radiolabel. In particular, the novel imaging agents disclosed herein have relatively high renal extraction efficiencies, and hence are useful for conducting renal function imaging procedures. The novel Tc-99m compounds of a present invention have the following general formula: ##STR1## wherein X is S or N; and wherein Y is --H or wherein Y is ##STR2## and where R.sub.1 is --H, --CH.sub.3, or --CH.sub.2 CH.sub.3 ; R.sub.2 is --H, --CH.sub.2 CO.sub.2 H, --CH.sub.2 CONH.sub.2, --CH.sub.2 CH.sub.2 CO.sub.2 H, --CH.sub.2 CH.sub.2 CONH.sub.2, --CH.sub.3, --CH.sub.2 CH.sub.3, CH.sub.2 C.sub.6 H.sub.5, or --CH.sub.2 OH; and Z is --H, --CO.sub.2 H, --CONH.sub.2, --SO.sub.3 H, --SO.sub.2 NH.sub.2, or --CONHCH.sub.2 CO.sub.2 H; and the Tc is Tc-99m; and water-soluble salts thereof. Of the foregoing, the presently preferred Tc-99m compound of the present invention is Tc-99m-mercaptoacetylglycylglycylglycine (Tc-99m-MAGGG). The present invention is also directed to novel chelating agents that may be reacted with Tc-99m to form the foregoing compounds. Such novel chelating agents have the following general formula. ##STR3## where X and Y have the same definitions as above, and wherein Y' is --H.sub.2 when X is N, or wherein Y' is --H, or a suitable protective group such as --COCH.sub.3, --COC.sub.6 H.sub.5, --CH.sub.2 NHCOCH.sub.3, --COCF.sub.3, or --COCH.sub.2 OH when X is S. The present invention also provides methods for preparing and using the novel Tc-99m compounds.

  17. Radiolabeled technetium chelates for use in renal function determinations

    DOEpatents

    Fritzberg, Alan (Edmonds, WA); Kasina, Sudhakar (Kirkland, WA); Johnson, Dennis L. (Las Cruces, NM)

    1990-01-01

    The present invention is directed to novel radiopharmaceutical imaging agents incorporating Tc-99m as a radiolabel. In particular, the novel imaging agents disclosed herein have relatively high renal extraction efficiencies, and hence are useful for conducting renal function imaging procedures. The novel Tc-99m compounds of a present invention have the following general formula: ##STR1## wherein X is S or N; and wherein Y is--H or wherein Y is ##STR2## and where R.sub.1 is --H, --CH.sub.3, or --CH.sub.2 CH.sub.3 ; R.sub.2 is --H, --CH.sub.2 CO.sub.2 H, --CH.sub.2 CONH.sub.2, --CH.sub.2 CH.sub.2 CO.sub.2 H, --CH.sub.2 CH.sub.2 CONH.sub.2, --CH.sub.3, --CH.sub.2 CH.sub.3, CH.sub.2 C.sub.6 H.sub.5, or --CH.sub.2 OH; and Z is --H, --CO.sub.2 H, --CONH.sub.2, --SO.sub.3 H, --SO.sub.2 NH.sub.2, or --CONHCH.sub.2 CO.sub.2 H; and the Tc is Tc-99m; and water-soluble salts thereof. Of the foregoing, the presently preferred Tc-99m compound of the present invention is Tc-99m-mercaptoacetylglycylglycylglycine (Tc-99m-MAGGG). The present invention is also directed to novel chelating agents that may be reacted with Tc-99m to form the foregoing compounds. Such novel chelating agents have the following general formula. ##STR3## where X and Y have the same definitions as above, and wherein Y' is --H.sub.2 when X is N, or wherein Y' is --H, or a suitable protective group such as --COCH.sub.3, --COC.sub.6 H.sub.5, --CH.sub.2 NHCOCH.sub.3, --COCF.sub.3, or --COCH.sub.2 OH when X is S. The present invention also provides methods for preparing and using the novel Tc-99m compounds.

  18. Enhancement of bismuth antibacterial activity with lipophilic thiol chelators.

    PubMed Central

    Domenico, P; Salo, R J; Novick, S G; Schoch, P E; Van Horn, K; Cunha, B A

    1997-01-01

    The antibacterial properties of bismuth are greatly enhanced when bismuth is combined with certain lipophilic thiol compounds. Antibacterial activity was enhanced from 25- to 300-fold by the following seven different thiols, in order of decreasing synergy: 1,3-propanedithiol, dimercaprol (BAL), dithiothreitol, 3-mercapto-2-butanol, beta-mercaptoethanol, 1-monothioglycerol, and mercaptoethylamine. The dithiols produced the greatest synergy with bismuth at optimum bismuth-thiol molar ratios of from 3:1 to 1:1. The monothiols were generally not as synergistic and required molar ratios of from 1:1 to 1:4 for optimum antibacterial activity. The most-active mono- or dithiols were also the most soluble in butanol. The intensity of the yellow formed by bismuth-thiol complexes reflected the degree of chelation and correlated with antibacterial potency at high molar ratios. The bismuth-BAL compound (BisBAL) was active against most bacteria, as assessed by broth dilution, agar diffusion, and agar dilution analyses. Staphylococci (MIC, 5 to 7 microM Bi3+) and Helicobacter pylori (MIC, 2.2 microM) were among the most sensitive bacteria. Gram-negative bacteria were sensitive (MIC, < 17 microM). Enterococci were relatively resistant (MIC, 63 microM Bi3+). The MIC range for anaerobes was 15 to 100 microM Bi3+, except for Clostridium difficile (MIC, 7.5 microM). Bactericidal activity averaged 29% above the MIC. Bactericidal activity increased with increasing pH and/or increasing temperature. Bismuth-thiol solubility, stability, and antibacterial activity depended on pH and the bismuth-thiol molar ratio. BisBAL was stable but ineffective against Escherichia coli at pH 4. Activity and instability (reactivity) increased with increasing alkalinity. BisBAL was acid soluble at a molar ratio of greater than 3:2 and alkaline soluble at a molar ratio of less than 2:3. In conclusion, certain lipophilic thiol compounds enhanced bismuth antibacterial activity against a broad spectrum of bacteria. The activity, solubility, and stability of BisBAL were strongly dependent on the pH, temperature, and molar ratio. Chelation of bismuth with certain thiol agents enhanced the solubility and lipophilicity of this cationic heavy metal, thereby significantly enhancing its potency and versatility as an antibacterial agent. PMID:9257744

  19. Frequency-domain measurement of luminescent lanthanide chelates.

    PubMed

    Hyppnen, Iko; Soukka, Tero; Kankare, Jouko

    2010-08-01

    The sinusoidal modulation of excitation intensity and phase-sensitive detection of emission is ideally suitable for the accurate determination of the lifetime and intensity of lanthanide luminescence. In this work we elaborate on the general mathematical and instrumental techniques of the frequency-domain (FD) measurements in the low-frequency domain below 100 kHz. A modular FD luminometer is constructed by using a UV-LED as the excitation source, proper light filters in the excitation and emission paths, a photomultiplier with a fast preamplifier, and a conventional dual-phase lock-in amplifier. Starting from the set of linear differential equations governing the excited-state processes of the lanthanide chelates, an equation linking the luminescence intensity to the general form of the excitation modulation was derived. Application to the sinusoidal modulation in the Euler's exponential form gives the expression for the in-phase and out-of-phase signals of a dual-phase lock-in amplifier. It is shown that by using a relatively large number of logarithmically equidistant modulation frequencies it is possible to use the Kramers-Kronig relation for checking the compatibility of the out-of-phase and in-phase signals. As an example, the emission from two different europium(III) chelates were measured by using 200 modulation frequencies between 10 Hz and 100 kHz. In addition to the conventional transition between (5)D(0) and (7)F(2) levels emitting at 615 nm, also the emission from the transition between (5)D(1) and (7)F(1) levels at ca. 540 nm was measured. The latter emission was also measured at different temperatures, yielding the energy difference between the (5)D(1) and (5)D(0) levels. The relatively large number of modulation frequencies allows also an accurate determination of lifetimes and corresponding amplitudes by using an appropriate nonlinear regression method. Comparison of the time-domain and frequency-domain methods shows that the weighting of data is different and both methods have application areas of their own. PMID:20617797

  20. Modifications of boronic ester pro-chelators triggered by hydrogen peroxide tune reactivity to inhibit metal-promoted oxidative stress.

    PubMed

    Charkoudian, Louise K; Pham, David M; Kwon, Ashley M; Vangeloff, Abbey D; Franz, Katherine J

    2007-11-21

    Several new analogs of salicylaldehyde isonicotinoyl hydrazone (SIH) and salicylaldehyde benzoyl hydrazone (SBH) that contain an aryl boronic ester (BSIH, BSBH) or acid (BASIH) in place of an aryl hydroxide have been synthesized and characterized as masked metal ion chelators. These pro-chelators show negligible interaction with iron(III), although the boronic acid versions exhibit some interaction with copper(II), zinc(II) and nickel(II). Hydrogen peroxide oxidizes the aryl boronate to phenol, thus converting the pro-chelators to tridentate ligands with high affinity metal binding properties. An X-ray crystal structure of a bis-ligated iron(III) complex, [Fe(SBH(m-OMe)(3))(2)]NO(3), confirms the meridonal binding mode of these ligands. Modifications of the aroyl ring of the chelators tune their iron affinity, whereas modifications on the boron-containing ring of the pro-chelators attenuate their reaction rates with hydrogen peroxide. Thus, the methoxy derivative pro-chelator (p-OMe)BASIH reacts with hydrogen peroxide nearly 5 times faster than the chloro derivative (m-Cl)BASIH. Both the rate of pro-chelator to chelator conversion as well as the metal binding affinity of the chelator influence the overall ability of these molecules to inhibit hydroxyl radical formation catalyzed by iron or copper in the presence of hydrogen peroxide and ascorbic acid. This pro-chelator strategy has the potential to improve the efficacy of medicinal chelators for inhibiting metal-promoted oxidative stress. PMID:17992288

  1. A Speciation Study on the Perturbing Effects of Iron Chelators on the Homeostasis of Essential Metal Ions

    PubMed Central

    2015-01-01

    A number of reports have appeared in literature calling attention to the depletion of essential metal ions during chelation therapy on β-thalassaemia patients. We present a speciation study to determine how the iron chelators used in therapy interfere with the homeostatic equilibria of essential metal ions. This work includes a thorough analysis of the pharmacokinetic properties of the chelating agents currently in clinical use, of the amounts of iron, copper and zinc available in plasma for chelation, and of all the implied complex formation constants. The results of the study show that a significant amount of essential metal ions is complexed whenever the chelating agent concentration exceeds the amount necessary to coordinate all disposable iron —a frequently occurring situation during chelation therapy. On the contrary, copper and zinc do not interfere with iron chelation, except for a possible influence of copper on iron speciation during deferiprone treatment. PMID:26192307

  2. Combined chelation therapy with deferoxamine and deferiprone in ?-thalassemia major: compliance and opinions of young thalassemic patients.

    PubMed

    Hatzipantelis, Emmanuel S; Karasmanis, Konstantinos; Perifanis, Vassilios; Vlachaki, Efthimia; Tziomalos, Konstantinos; Economou, Marina

    2014-01-01

    Treatment of ?-thalassemia major (?-TM) includes regular blood transfusions and iron chelation with subcutaneous injection of deferoxamine (DFO). During the last decade, a new chelation agent, deferiprone (L1), was introduced. The purpose of our study was to determine the level of awareness/education regarding chelation therapy, the degree of compliance to this therapy and their views of L1 in patients with ?-TM. A relevant questionnaire was administered to 36 patients (12-26 years old) who were on combination chelation therapy with both DFO and L1. The majority of patients was well aware/educated about chelation therapy (76.6%), was compliant with this therapy (74.4%) and had a positive view towards oral chelation (86.0%). In conclusion, most patients with ?-TM who were on combination chelation therapy with DFO and L1 were satisfied with this treatment and this results in high compliance rates. PMID:24351163

  3. Bifunctional Indenyl-Derived Receptors for Fluoride Chelation and Detection.

    PubMed

    Tirfoin, Rmi; Abdalla, Joseph A B; Aldridge, Simon

    2015-08-10

    Anion receptors based on a [CpFe(indenyl)] scaffold offer the possibility for the incorporation of adjacent Lewis acidic functions onto a six-membered carbocyclic framework, while at the same time retaining the colorimetric/electrochemical reporter mechanisms available to synthetically simpler ferrocene systems. Thus, [CpFe(indenyl)] systems featuring mutually ortho BMes2 and PPh2 Me(+) substituents (with either 4,5 or 5,6 regiochemistry) are accessible which are capable of cooperative fluoride ion fixation. Simultaneous binding at the borane and phosphonium centres can be established by spectroscopic, structural and computational approaches, and is responsible for the favourable thermodynamics associated with F(-) uptake. Thus, in contrast to simple BMes2 systems, the binding of fluoride is found to be more favourable than the uptake of cyanide (which interacts only with the borane Lewis acid). Moreover, in the case of a 4-(MePh2 P)-5-(Mes2 B)-7-Me-indenyl derivative, fluoride chelation is signalled not only by a large cathodic shift in the Fe(II) /Fe(III) potential (>500?mV in THF), but also by a distinct colour change from green (for the free receptor) to maroon for the adduct. PMID:26179477

  4. Chelating water-soluble polymers for waste minimization

    SciTech Connect

    Smith, B.; Cournoyer, M.; Duran, B.; Ford, D.; Gibson, R.; Lin, M.; Meck, A.; Robinson, P.; Robison, T.

    1996-11-01

    Within the DOE complex and in industry there is a tremendous need for advanced metal ion recovery and waste minimization techniques. This project sought to employ capabilities for ligand-design and separations chemistry in which one can develop and evaluate water- soluble chelating polymers for recovering actinides and toxic metals from various process streams. Focus of this work was (1) to develop and select a set of water-soluble polymers suitable for a selected waste stream and (2) demonstrate this technology in 2 areas: removal of (a) actinides and toxic RCRA metals from waste water and (b) recovery of Cu and other precious metals from industrial process streams including from solid catalysts and aqueous waste streams. The R&D was done in 4 phases for each of the 2 target areas: polymer synthesis for scaleup, equipment assembly, process demonstration at a DOE or industrial site, and advanced ligand/polymer synthesis. The TA- 50 site at Los Alamos was thought to be appropriate due to logistics and to its being representative of similar problems throughout the DOE complex.

  5. Chelating ability and biological activity of hesperetin Schiff base.

    PubMed

    Lodyga-Chruscinska, Elzbieta; Symonowicz, Marzena; Sykula, Anna; Bujacz, Anna; Garribba, Eugenio; Rowinska-Zyrek, Magdalena; Oldziej, Stanislaw; Klewicka, Elzbieta; Janicka, Magdalena; Krolewska, Karolina; Cieslak, Marcin; Brodowska, Katarzyna; Chruscinski, Longin

    2015-02-01

    Hydrazone hesperetin Schiff base (HHSB) - N-[()-[5,7-dihydroxy-2-(3-hydroxy-4-methoxy-phenyl)chroman-4-ylidene]amino]benzamide has been synthesized and its crystal structure was determined. This compound was used for the formation of Cu(II) complexes in solid state and in solution which were characterized using different spectroscopic methods. The analyses of potentiometric titration curves revealed that monomeric and dimeric complexes of Cu(II) are formed above pH7. The ESI-MS (electrospray ionization-mass spectrometry) spectra confirmed their formation. The EPR and UV-visible spectra evidenced the involvement of oxygen and nitrogen atoms in Cu(II) coordination. Hydrazone hesperetin Schiff base can show keto-enol tautomerism and coordinate Cu(II) in the keto (O(-), N, Oket) and in the enolate form (O(-), N, O(-)enol). The semi-empirical molecular orbital method PM6 and DFT (density functional theory) calculations have revealed that the more stable form of the dimeric complex is that one in which the ligand is present in the enol form. The CuHHSB complex has shown high efficiency in the cleavage of plasmid DNA in aqueous solution, indicating its potential as chemical nuclease. Studies on DNA interactions, antimicrobial and cytotoxic activities have been undertaken to gain more information on the biological significance of HHSB and copper(II)-HHSB chelate species. PMID:25486205

  6. Lead analysis by anti-chelate fluorescence polarization immunoassay.

    PubMed

    Johnson, David K; Combs, Sherry M; Parsen, John D; Jolley, Michael E

    2002-03-01

    Lead concentrations were determined by a fluorescence polarization immunoassay (FPIA) method that uses polyclonal antibodies raised against the lead(II) chelate of ethylenediamine-N,N,N',N'-tetraacetic acid (EDTA). The technique is based on competition for a fixed concentration of antibody binding sites between Pb-EDTA, formed by treating the sample with excess EDTA, and a fixed concentration of a fluorescent analogue of the Pb-EDTA complex. The objective was to correlate results obtained by FPIA with those produced by conventional atomic spectroscopy analysis of soils, solid waste leachates (produced by the Toxicity Characteristic Leachate Procedure; TCLP), airborne dust, and drinking water. Linear regression analysis of FPIA results for 138 soil samples containing 0-3094 ppm Pb(II) by flame atomic absorption spectroscopy and 40 TCLP extracts containing 0-668 ppm Pb(II) by inductively coupled plasma atomic emission spectroscopy produced correlation coefficients (r2) of 0.96 and 0.93, respectively. Pilot studies of mineral acid extracts of airborne dust trapped on fiberglass filters and of two sources of drinking water demonstrated the feasibility of also measuring lead in these matrixes by FPIA. The limit of detection under conditions that minimized sample dilution was approximately 1 ppb, and cross reactivity with 15 nontarget metals was below 0.5% in all cases. The methods are simple to perform and are amenable to field testing and mobile laboratory use, allowing timely and cost-effective characterization of suspected sources of lead contamination. PMID:11917989

  7. Synthesis and characterizations of pyridazine-based iron chelators.

    PubMed

    Ma, Yongmin; Kong, Xiaole; Chen, Yu-lin; Hider, Robert C

    2014-12-01

    In an attempt to design ligands which require both a high iron(III) affinity and a low iron(II) affinity, the 3-hydroxypyridin-4-one structure has been modified to introduce an additional nitrogen atom in the pyridine ring to form a pyridazine. The target molecules were synthesized from a chlorine-substituted pyridazine using step-by-step methoxylations. A total of six 3- and 5-hydroxypyridazin-4(1H)-ones have been synthesized, with a methyl, ethyl or n-propyl group on the N1 of the pyridazine ring. In the reaction of the pyridazines with alkyl iodide, the presence of acetone drives the reaction to afford pyridazinones rather than the desired pyridaziniums. The pK(a) values of the free ligands, the stability constants of their iron(III) complexes and corresponding pFe(III) values demonstrate that this type of ligand has lower values when compared with those of deferiprone. The reduction potential values of the iron complexes obtained from cyclic voltammetry measurements, are used to determine the corresponding pFe(II) values. Although two compounds of the 20 series have marginally higher log??3(Fe(III))/log??3(Fe(II)) ratios than those of deferiprone, they possess pFe(III) values <20, indicating that this type of chelator is unlikely to be optimized into a useful therapeutic agent. PMID:25311299

  8. Chelating stability of an amphoteric chelating polymer flocculant with Cu(II), Pb(II), Cd(II), and Ni(II)

    NASA Astrophysics Data System (ADS)

    Liu, Lihua; Li, Yanhong; Liu, Xing; Zhou, Zhihua; Ling, Yulin

    2014-01-01

    The absorption spectra of Cu2+, Pb2+, Cd2+, and Ni2+ chelates of an amphoteric chelating polymer flocculant (ACPF) were measured by ultraviolet spectrophotometry, and their compositions and stability constants (β) were calculated. ACPF exhibited three apparent absorption peaks at 204, 251, and 285 nm. The sbnd CSS- group of ACPF reacted with Cu2+, Ni2+, Pb2+, and Cd2+ to form ACPF-Cu2+, ACPF-Ni2+, ACPF-Pb2+, and ACPF-Cd2+ chelates, respectively, according to a molar ratio of 2:1. The maximum absorption peaks of ACPF-Cu2+, ACPF-Ni2+, ACPF-Pb2+, and ACPF-Cd2+ appeared at 319, 326, 310, and 313.5 nm, respectively. The maximum absorption peaks of the chelates showed significant red shifting compared with the absorption peaks of ACPF. The β values of the ACPF-Cu2+, ACPF-Pb2+, ACPF-Cd2+, and ACPF-Ni2+ chelates were (1.37 ± 0.35) × 1012, (3.26 ± 0.39) × 1011, (2.05 ± 0.27) × 1011, and (3.04 ± 0.45) × 1010, respectively. The leaching rate of heavy metal ions from the chelating precipitates decreased with increasing pH. ACPF-Cu2+, ACPF-Ni2+, ACPF-Pb2+, and ACPF-Cd2+ were very stable at pH ⩾ 5.6. Cu2+, Ni2+, Pb2+, and Cd2+ concentrations in the leaching liquors were lower than the corresponding limits specified by the Integrated Wastewater Discharge Standard of China.

  9. In Vivo Curative and Protective Potential of Orally Administered 5-Aminolevulinic Acid plus Ferrous Ion against Malaria

    PubMed Central

    Suzuki, Shigeo; Hikosaka, Kenji; Balogun, Emmanuel O.; Komatsuya, Keisuke; Niikura, Mamoru; Kobayashi, Fumie; Takahashi, Kiwamu; Tanaka, Tohru; Nakajima, Motowo

    2015-01-01

    5-Aminolevulinic acid (ALA) is a naturally occurring amino acid present in diverse organisms and a precursor of heme biosynthesis. ALA is commercially available as a component of cosmetics, dietary supplements, and pharmaceuticals for cancer diagnosis and therapy. Recent reports demonstrated that the combination of ALA and ferrous ion (Fe2+) inhibits the in vitro growth of the human malaria parasite Plasmodium falciparum. To further explore the potential application of ALA and ferrous ion as a combined antimalarial drug for treatment of human malaria, we conducted an in vivo efficacy evaluation. Female C57BL/6J mice were infected with the lethal strain of rodent malaria parasite Plasmodium yoelii 17XL and orally administered ALA plus sodium ferrous citrate (ALA/SFC) as a once-daily treatment. Parasitemia was monitored in the infected mice, and elimination of the parasites was confirmed using diagnostic PCR. Treatment of P. yoelii 17XL-infected mice with ALA/SFC provided curative efficacy in 60% of the mice treated with ALA/SFC at 600/300 mg/kg of body weight; no mice survived when treated with vehicle alone. Interestingly, the cured mice were protected from homologous rechallenge, even when reinfection was attempted more than 230 days after the initial recovery, indicating long-lasting resistance to reinfection with the same parasite. Moreover, parasite-specific antibodies against reported vaccine candidate antigens were found and persisted in the sera of the cured mice. These findings provide clear evidence that ALA/SFC is effective in an experimental animal model of malaria and may facilitate the development of a new class of antimalarial drug. PMID:26324278

  10. Near-infrared spectra of ferrous mineral mixtures and methods for their identification in planetary surface spectra

    NASA Astrophysics Data System (ADS)

    Horgan, Briony H. N.; Cloutis, Edward A.; Mann, Paul; Bell, James F.

    2014-05-01

    Iron-bearing minerals are a major component of planetary surfaces, and many can be identified by their characteristic absorption bands in the near-infrared (NIR). Here we present laboratory NIR spectra of a wide range of common Fe-bearing minerals (e.g., olivines, pyroxenes), glasses, and mineral/glass mixtures. We then use this suite of spectra to evaluate the effects of mixtures on mineral detection methods, including olivine and pyroxene spectral indices developed for the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) onboard Mars Reconnaissance Orbiter. We find that although these indices can be compromised by minerals with atypical compositions, mineral mixtures, and the presence of other ferrous minerals, these issues can generally be mitigated by visual inspection of the spectra. However, a special case occurs when the mineral or mixture in question is spectrally indistinguishable from a more common mineral. In particular, we show that spectra of high-calcium pyroxene mixed with Fe-bearing glass can be virtually indistinguishable from common Fe-bearing olivine compositions. This effect, combined with the fact that Fe-bearing glass is generally much more difficult to detect than other ferrous minerals, may be causing glass occurrences on planetary surfaces to be underreported. In support of this hypothesis, we use Mars Express OMEGA observations to show that previous olivine detections in the north polar sand sea on Mars are actually more consistent with local mixing of glass and pyroxene. To address these issues, we present an alternative ferrous mineral identification method based on the position and shape of the 1 and 2 ?m iron absorption bands, which are sensitive to mineralogy, composition, and mineral mixtures in planetary surface spectra, including glass and mixtures with glass. Using Chandrayaan-1 Moon Mineralogy Mapper (M3) observations of Aristarchus Crater on the Moon, we show that these band parameters can reveal subtle spectral variations and can produce mineralogical maps at an exceptional level of detail.

  11. Major Role for FeoB in Campylobacter jejuni Ferrous Iron Acquisition, Gut Colonization, and Intracellular Survival

    PubMed Central

    Naikare, Hemant; Palyada, Kiran; Panciera, Roger; Marlow, Denver; Stintzi, Alain

    2006-01-01

    To assess the importance of ferrous iron acquisition in Campylobacter physiology and pathogenesis, we disrupted and characterized the Fe2+ iron transporter, FeoB, in Campylobacter jejuni NCTC 11168, 81-176, and ATCC 43431. The feoB mutant was significantly affected in its ability to transport 55Fe2+. It accumulated half the amount of iron than the wild-type strain during growth in an iron-containing medium. The intracellular iron of the feoB mutant was localized in the periplasmic space versus the cytoplasm for the wild-type strain. These results indicate that the feoB gene of C. jejuni encodes a functional ferrous iron transport system. Reverse transcriptase PCR analysis revealed the cotranscription of feoB and Cj1397, which encodes a homolog of Escherichia coli feoA. C. jejuni 81-176 feoB mutants exhibited reduced ability to persist in human INT-407 embryonic intestinal cells and porcine IPEC-1 small intestinal epithelial cells compared to the wild type. C. jejuni NCTC 11168 feoB mutant was outcompeted by the wild type for colonization and/or survival in the rabbit ileal loop. The feoB mutants of the three C. jejuni strains were significantly affected in their ability to colonize the chick cecum. And finally, the three feoB mutants were outcompeted by their respective wild-type strains for infection of the intestinal tracts of colostrum-deprived piglets. Taken together, these results demonstrate that FeoB-mediated ferrous iron acquisition contributes significantly to colonization of the gastrointestinal tract during both commensal and infectious relationship, and thus it plays an important role in Campylobacter pathogenesis. PMID:16988218

  12. O{sub 2}-mediated oxidation of ferrous nitrosylated human serum heme-albumin is limited by nitrogen monoxide dissociation

    SciTech Connect

    Ascenzi, Paolo; National Institute for Infectious Diseases I.R.C.C.S. 'Lazzaro Spallanzani', Via Portuense 292, I-00149 Roma ; Gullotta, Francesca; Gioia, Magda; Coletta, Massimo; Interuniversity Consortium for the Research on the Chemistry of Metals in Biological Systems, Piazza Umberto I 1, I-87100 Bari ; Fasano, Mauro

    2011-03-04

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

  13. Protein dynamics and the all-ferrous [Fe4 S4 ] cluster in the nitrogenase iron protein.

    PubMed

    Tan, Ming-Liang; Perrin, B Scott; Niu, Shuqiang; Huang, Qi; Ichiye, Toshiko

    2016-01-01

    In nitrogen fixation by Azotobacter vinelandii nitrogenase, the iron protein (FeP) binds to and subsequently transfers electrons to the molybdenum-FeP, which contains the nitrogen fixation site, along with hydrolysis of two ATPs. However, the nature of the reduced state cluster is not completely clear. While reduced FeP is generally thought to contain an [Fe4 S4 ](1+) cluster, evidence also exists for an all-ferrous [Fe4 S4 ](0) cluster. Since the former indicates a single electron is transferred per two ATPs hydrolyzed while the latter indicates two electrons could be transferred per two ATPs hydrolyzed, an all-ferrous [Fe4 S4 ](0) cluster in FeP is potenially two times more efficient. However, the 1+/0 reduction potential has been measured in the protein at both 460 and 790 mV, causing the biological significance to be questioned. Here, "density functional theory plus Poisson Boltzmann" calculations show that cluster movement relative to the protein surface observed in the crystal structures could account for both measured values. In addition, elastic network mode analysis indicates that such movement occurs in low frequency vibrations of the protein, implying protein dynamics might lead to variations in reduction potential. Furthermore, the different reductants used in the conflicting measurements of the reduction potential could be differentially affecting the protein dynamics. Moreover, even if the all-ferrous cluster is not the biologically relevant cluster, mutagenesis to stabilize the conformation with the more exposed cluster may be useful for bioengineering more efficient enzymes. PMID:26271353

  14. In vivo curative and protective potential of orally administered 5-aminolevulinic acid plus ferrous ion against malaria.

    PubMed

    Suzuki, Shigeo; Hikosaka, Kenji; Balogun, Emmanuel O; Komatsuya, Keisuke; Niikura, Mamoru; Kobayashi, Fumie; Takahashi, Kiwamu; Tanaka, Tohru; Nakajima, Motowo; Kita, Kiyoshi

    2015-11-01

    5-Aminolevulinic acid (ALA) is a naturally occurring amino acid present in diverse organisms and a precursor of heme biosynthesis. ALA is commercially available as a component of cosmetics, dietary supplements, and pharmaceuticals for cancer diagnosis and therapy. Recent reports demonstrated that the combination of ALA and ferrous ion (Fe(2+)) inhibits the in vitro growth of the human malaria parasite Plasmodium falciparum. To further explore the potential application of ALA and ferrous ion as a combined antimalarial drug for treatment of human malaria, we conducted an in vivo efficacy evaluation. Female C57BL/6J mice were infected with the lethal strain of rodent malaria parasite Plasmodium yoelii 17XL and orally administered ALA plus sodium ferrous citrate (ALA/SFC) as a once-daily treatment. Parasitemia was monitored in the infected mice, and elimination of the parasites was confirmed using diagnostic PCR. Treatment of P. yoelii 17XL-infected mice with ALA/SFC provided curative efficacy in 60% of the mice treated with ALA/SFC at 600/300 mg/kg of body weight; no mice survived when treated with vehicle alone. Interestingly, the cured mice were protected from homologous rechallenge, even when reinfection was attempted more than 230 days after the initial recovery, indicating long-lasting resistance to reinfection with the same parasite. Moreover, parasite-specific antibodies against reported vaccine candidate antigens were found and persisted in the sera of the cured mice. These findings provide clear evidence that ALA/SFC is effective in an experimental animal model of malaria and may facilitate the development of a new class of antimalarial drug. PMID:26324278

  15. Bis(imino)pyridine iron alkyls containing beta-hydrogens: synthesis, evaluation of kinetic stability, and decomposition pathways involving chelate participation.

    PubMed

    Trovitch, Ryan J; Lobkovsky, Emil; Chirik, Paul J

    2008-09-01

    Bis(imino)pyridine iron alkyl complexes bearing beta-hydrogens, ((iPr)PDI)FeR (((iPr)PDI = 2,6-(2,6-(i)Pr2-C6H3N=CMe)2C5H3N; R = Et, (n)Bu, (i)Bu, CH2 (cyclo)C5H 9; 1-R), were synthesized either by direct alkylation of ((iPr)PDI)FeCl (1-Cl) with the appropriate Grignard reagent or more typically by oxidative addition of the appropriate alkyl bromide to the iron bis(dinitrogen) complex, ((iPr)PDI)Fe(N2)2 (1-(N2)2). In the latter method, the formal oxidative addition reaction produced ((iPr)PDI)FeBr (1-Br), along with the desired iron alkyl, 1-R. Elucidation of the electronic structure of 1-Br and related 1-R derivatives by magnetic measurements, structural studies and NMR spectroscopy established high spin ferrous compounds antiferromagnetically coupled to chelate radical anions. Thus, the formal oxidative process is bis(imino)pyridine ligand-based (one electron is formally removed from each chelate, not the iron) during oxidative addition. The kinetic stability of each 1-R compound was assayed in benzene-d6 solution and found to produce a mixture of the corresponding alkane and alkene. The kinetic stability of the iron alkyl complexes was inversely correlated with the number of beta-hydrogens present. For example, the iron ethyl complex, 1-Et, underwent clean loss of ethane over the course of three hours, whereas the corresponding 1-(i)Bu compound had a half-life of over 12 h under identical conditions. The mechanism of the decomposition was studied with a series of deuterium labeling experiments and support a pathway involving initial beta-hydrogen elimination followed by cyclometalation of an isopropyl methyl group, demonstrating an overall transfer hydrogenation pathway. The relevance of such pathways to chain transfer in bis(imino)pyridine iron catalyzed olefin polymerization reactions is also presented. PMID:18686955

  16. BENCH-SCALE RECOVERY OF LEAD USING AND ELECTRO- MEMBRANE/CHELATION PROCESS

    EPA Science Inventory

    This report presents the results of a bench-scale treatability test to investigate key process parameters influencing an innovative chelation electrodeposition process for recovery of lead from contaminated sons. thylenediamine tetraacetic acid (EDTA) and diethylenetriamine penta...

  17. CONTROL OF CHELATOR-BASED UPSETS IN SURFACE FINISHING SHOP WASTE WATER TREATMENT SYSTEMS

    EPA Science Inventory

    Actual surface finishing shop examples are used to illustrate the use of process chemistry understanding and analyses to identify immediate, interim and permanent response options for industrial waste water treatment plant (IWTP) upset problems caused by chelating agents. There i...

  18. Bifunctional chelates of RH-105 and AU199 as potential radiotherapeutic agents

    SciTech Connect

    Droege, P.

    1997-03-01

    Research is presented on new bifunctional chelating ligand systems with stability on the macroscopic and radiochemical levels. The synthesis of the following complexes are described: rhodium 105, palladium 109, and gold 198.

  19. Bifunctional chelating agent for the design and development of site specific radiopharmaceuticals and biomolecule conjugation strategy

    DOEpatents

    Katti, Kattesh V.; Prabhu, Kandikere R.; Gali, Hariprasad; Pillarsetty, Nagavara Kishore; Volkert, Wynn A.

    2003-10-21

    There is provided a method of labeling a biomolecule with a transition metal or radiometal in a site specific manner to produce a diagnostic or therapeutic pharmaceutical compound by synthesizing a P.sub.2 N.sub.2 -bifunctional chelating agent intermediate, complexing the intermediate with a radio metal or a transition metal, and covalently linking the resulting metal-complexed bifunctional chelating agent with a biomolecule in a site specific manner. Also provided is a method of synthesizing the --PR.sub.2 containing biomolecules by synthesizing a P.sub.2 N.sub.2 -bifunctional chelating agent intermediate, complexing the intermediate with a radiometal or a transition metal, and covalently linking the resulting radio metal-complexed bifunctional chelating agent with a biomolecule in a site specific manner. There is provided a therapeutic or diagnostic agent comprising a --PR.sub.2 containing biomolecule.

  20. Synthesis of yttrium iron garnet using polymer-metal chelate precursor.

    PubMed

    Wang, Cheng-Chien; Yu, Wei-Ting

    2007-02-15

    Two kinds of polymer-metal compounds, heterogeneous complexes (metal-chelating copolymer microspheres, MCP) and homogeneous complexes (water-soluble metal-chelating polymers, WSMCP), were synthesized to act as nucleation agents for YIG precursor preparation in this text. Both of the metal-chelating polymers have the same chelating group and high metal ion adsorption ability from the FTIR and ICP measurement. Furthermore, good YIG crystals can be obtained by treating the MCP precursor with a low calcination temperature at 600 degrees C from the XRD spectra and TEM micrograph. However, the YIG crystal obtained using a WSMCP precursor should be synthesized at a higher calcination temperature (>900 degrees C) due to the different components of the YIG precursor. In addition, the YIG crystal obtained by using the MCP precursor had nearly superparamagnetic behavior after VSM examination. PMID:17118383