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Sample records for nanophase ferric oxide

  1. High Resolution Transmission Electron Microscopy (HRTEM) of nanophase ferric oxides

    NASA Technical Reports Server (NTRS)

    Golden, D. C.; Morris, R. V.; Ming, D. W.; Lauer, H. V., Jr.

    1994-01-01

    Iron oxide minerals are the prime candidates for Fe(III) signatures in remotely sensed Martian surface spectra. Magnetic, Mossbauer, and reflectance spectroscopy have been carried out in the laboratory in order to understand the mineralogical nature of Martian analog ferric oxide minerals of submicron or nanometer size range. Out of the iron oxide minerals studied, nanometer sized ferric oxides are promising candidates for possible Martian spectral analogs. 'Nanophase ferric oxide (np-Ox)' is a generic term for ferric oxide/oxihydroxide particles having nanoscale (less than 10 nm) particle dimensions. Ferrihydrite, superparamagnetic particles of hematite, maghemite and goethite, and nanometer sized particles of inherently paramagnetic lepidocrocite are all examples of nanophase ferric oxides. np-Ox particles in general do not give X-ray diffraction (XRD) patterns with well defined peaks and would often be classified as X-ray amorphous. Therefore, different np-Oxs preparations should be characterized using a more sensitive technique e.g., high resolution transmission electron microscopy (HRTEM). The purpose of this study is to report the particle size, morphology and crystalline order, of five np-Ox samples by HRTEM imaging and electron diffraction (ED).

  2. Nanophase iron oxides as a key ultraviolet sunscreen for ancient photosynthetic microbes

    NASA Astrophysics Data System (ADS)

    Bishop, Janice L.; Louris, Stephanie K.; Rogoff, Dana A.; Rothschild, Lynn J.

    2006-07-01

    We propose that nanophase iron-oxide-bearing materials provided important niches for ancient photosynthetic microbes on the Earth that ultimately led to the oxygenation of the Earth's atmosphere and the formation of iron-oxide deposits. Atmospheric oxygen and ozone attenuate ultraviolet radiation on the Earth today providing substantial protection for photosynthetic organisms. With ultraviolet radiation fluxes likely to have been even higher on the early Earth than today, accessing solar radiation was particularly risky for early organisms. Yet, we know that photosynthesis arose early and played a critical role in subsequent evolution. Of primary importance was protection below 290 nm, where peak nucleic acid (~260 nm) and protein (~280 nm) absorptions occur. Nanophase ferric oxide/oxyhydroxide minerals absorb, and thus block, the lethal ultraviolet radiation, while transmitting light through much of the visible and near-infrared regions of interest to photosynthesis (400 to 1100 nm). Furthermore, they were available in early environments, and are synthesized by many organisms. Based on experiments using nanophase ferric oxide/oxyhydroxide minerals as a sunscreen for photosynthetic microbes, we suggest that iron, an abundant element widely used in biological mechanisms, may have provided the protection that early organisms needed in order to be able to use photosynthetically active radiation while being protected from ultraviolet-induced damage. The results of this study are broadly applicable to astrobiology because of the abundance of iron in other potentially habitable bodies and the evolutionary pressure to utilize solar radiation when available as an energy source. This model could apply to a potential life form on Mars or other bodies where liquid water and ultraviolet radiation could have been present at significant levels. Based on ferric oxide/oxyhydroxide spectral properties, likely geologic processes, and the results of experiments with the photosynthetic organisms, Euglena sp. and Chlamydomonas reinhardtii, we propose a scenario where photosynthesis, and ultimately the oxygenation of the atmosphere, depended on the protection of early microbes by nanophase ferric oxides/oxyhydroxides.

  3. Nanophase Iron Oxides as an Ultraviolet Sunscreen for Ancient Photosynthetic Microbes: A Possible Link Between Early Organisms, Banded-Iron Formations, and the Oxygenation of the Atmosphere

    NASA Technical Reports Server (NTRS)

    Bishop, Janice L.; Rothschild, Lynn J.; Rothschild, Lynn J.; Rogoff, Dana A.

    2006-01-01

    We propose that nanophase iron oxide-bearing materials provided important niches for ancient photosynthetic microbes on the early Earth that ultimately led to the oxygenation of the Earth s atmosphere and the formation of iron oxide deposits. Atmospheric oxygen and ozone attenuate UV radiation on the Earth today providing substantial protection for photosynthetic organisms. With ultraviolet radiation fluxes likely to have been even higher on the early Earth than today, accessing solar radiation was particularly risky for early organisms. Yet, we know that photosynthesis arose then and played a critical role in subsequent evolution. Of primary importance was protection at approx.250-290 nm, where peak nucleic acid (approx.260 nm) and protein (approx.280 nm) absorptions occur. Nanophase ferric oxide/oxyhydroxide minerals absorb, and thus block, the lethal UV radiation, while transmitting light through much of the visible and near-infrared regions of interest to photosynthesis (400 to 1100 nm). Further, they were available in early environments, and are synthesized by many organisms. Based on ferric oxide/oxyhydroxide spectral properties, likely geologic processes, and the results of experiments with the photosynthetic organisms, Euglena sp. and Chlumydomonus reinhardtii, we propose a scenario where photosynthesis, and ultimately the oxygenation of the atmosphere, depended on the protection of early microbes by nanophase ferric oxides/oxyhydroxides. The results of this study are also applicable to other potentially habitable iron-bearing planetary bodies because of the evolutionary pressure to utilize solar radiation when available as an energy source.

  4. Irradiation of Anorthite by Iron Ions-A Simulation of the Solar Wind Origin of Nanophase Iron in Lunar Soil

    NASA Astrophysics Data System (ADS)

    Li, Y.; Li, X. Y.; Wu, Y. X.; Li, S. J.; Wang, S. J.

    2015-07-01

    We present a simulant study of the origin of nanophase iron particles that implanted into the lunar soil particles by solar wind. Iron, ferroferric oxide and ferric oxide were identified and their origins were discussed.

  5. Microwave drying of ferric oxide pellets

    SciTech Connect

    Pickles, C.A.; Xia, D.K.

    1997-12-31

    The application of microwave energy for the drying of ferric oxide pellets has been investigated and evaluated. It is shown that the microwave drying rates are much higher than those observed in the conventional process. Also there is some potential for improved quality of the product. As a stand-alone technology it is unlikely that microwave drying would be economical for pellets due to the low cost of conventional fuels. However, based on an understanding of the drying mechanisms in the conventional process and in the microwave process, it is shown that microwave-assisted drying offers considerable potential. In this hybrid process, the advantages of the two drying techniques are combined to provide an improved drying process.

  6. Ferric iron reduction by sulfur- and iron-oxidizing bacteria.

    PubMed Central

    Brock, T D; Gustafson, J

    1976-01-01

    Acidophilic bacteria of the genera Thiobacillus and Sulfolobus are able to reduce ferric iron when growing on elemental sulfur as an energy source. It has been previously thought that ferric iron serves as a nonbiological oxidant in the formation of acid mine drainage and in the leaching of ores, but these results suggest that bacterial catalysis may play a significant role in the reactivity of ferric iron. PMID:825043

  7. NMR study of nanophase Al/Al-oxide powder and consolidated composites

    SciTech Connect

    Suits, B.H.; Apte, P.; Wilken, D.E.; Siegel, R.W.

    1994-10-01

    {sup 27}Al Nuclear Magnetic Resonance (NMR) measurements from aluminum powders and consolidated nanophase aluminum made from those powders are presented. The signals from the metal and surface oxidation are easily separated and are compared before and after consolidation. The results presented indicate that the oxide coating becomes the interface region within the nanophase composite material and that during consolidation the metal has undergone a deformation equivalent to that seen for bulk material under a compressive strain of between 4% and 8%.

  8. Pigmenting agents in Martian soils: inferences from spectral, Mossbauer, and magnetic properties of nanophase and other iron oxides in Hawaiian palagonitic soil PN-9

    NASA Technical Reports Server (NTRS)

    Morris, R. V.; Golden, D. C.; Lauer, H. V. Jr; Adams, J. B.

    1993-01-01

    We have examined a Hawaiian palagonitic tephra sample (PN-9) that has spectroscopic similarities to Martian bright regions using a number of analytical techniques, including Mossbauer and reflectance spectroscopy, X-ray diffraction, instrumental neutron activation analysis, electron probe microanalysis, transmission electron microscopy, and dithionite-citrate-bicarbonate extraction. Chemically, PN-9 has a Hawaiitic composition with alkali (and presumably silica) loss resulting from leaching by meteoric water during palagonitization; no Ce anomaly is present in the REE pattern. Mineralogically, our results show that nanophase ferric oxide (np-Ox) particles (either nanophase hematite (np-Hm) or a mixture of ferrihydrite and np-Hm) are responsible for the distinctive ferric doublet and visible-wavelength ferric absorption edge observed in Mossbauer and reflectivity spectra, respectively, for this and other spectrally similar palagonitic samples. The np-Ox particles appear to be imbedded in a hydrated aluminosilicate matrix material; no evidence was found for phyllosilicates. Other iron-bearing phases observed are titanomagnetite, which accounts for the magnetic nature of the sample; olivine; pyroxene; and glass. By analogy, np-Ox is likely the primary pigmenting agent of the bright soils and dust of Mars.

  9. ADSORPTION OF TRACE METALS BY HYDROUS FERRIC OXIDE IN SEAWATER

    EPA Science Inventory

    The adsorption of trace metals by amorphous hydrous ferric oxide in seawater is studied with reference to simple model systems designed to isolate the factors which may have an effect on the isotherms. Results show that the complex system behaves in a remarkably simple way and th...

  10. Lunar dust simulant containing nanophase iron and method for making the same

    NASA Technical Reports Server (NTRS)

    Hung, Chin-cheh (Inventor); McNatt, Jeremiah (Inventor)

    2012-01-01

    A lunar dust simulant containing nanophase iron and a method for making the same. Process (1) comprises a mixture of ferric chloride, fluorinated carbon powder, and glass beads, treating the mixture to produce nanophase iron, wherein the resulting lunar dust simulant contains .alpha.-iron nanoparticles, Fe.sub.2O.sub.3, and Fe.sub.3O.sub.4. Process (2) comprises a mixture of a material of mixed-metal oxides that contain iron and carbon black, treating the mixture to produce nanophase iron, wherein the resulting lunar dust simulant contains .alpha.-iron nanoparticles and Fe.sub.3O.sub.4.

  11. NMR study and hardness behavior of nanophase Al/Al-oxide consolidated composite

    NASA Astrophysics Data System (ADS)

    Apte, Palash Prakash

    Over the past few years, nanostructured materials (grain sizes 1-100 nm) have generated a lot of interest in the scientific community. This interest has mainly stemmed from the reported superior properties of these materials over conventional ones and their potential for commercial applications. A variety of techniques including SEM, TEM, PAS, etc. have been used to study nanophase materials. This work reports the study of a nanophase composite material using the non-destructive NMR spectroscopic technique. The composite studied is a nanophase Al/Al-Oxide system with the Al metal in the grains and the Al-Oxide in the grain boundaries. The production of such a nanoscale Al/Al-Oxide powder is described. Hardness, mass density and electrical conductivity measurements on the pellets formed by the consolidation of this powder at different consolidation pressures is reported. NMR studies of this composite material are reported at room temperature. The design and construction of a high temperature NMR probe is described. Limited high temperature NMR measurements are then described. Hardness measurements conducted on the samples indicate an increase in hardness with decrease in grain size in accordance with the Hall-Petch relationship. Interestingly, some of the samples were electrically conducting and some non-conducting. An increase in hardness with an insignificant change in mass density was observed in some samples. High temperature NMR results indicate the melting of the Al metal within the oxide at or around the melting point of aluminum (660spC). X-Ray measurements show no evidence of grain growth with increase in temperature. Both the X-Ray and NMR measurements show a substantial increase in the aluminum-oxide content of the samples after heating. NMR measurements performed on the samples before and after heating show a non-reversible behavior of the samples upon heating with respect to their signal intensity. Hardness tests performed on the samples after heating them indicate an increase in hardness by as much as a factor of five as compared to the hardness of the unheated samples. In conclusion, the experiments have successfully demonstrated the synthesis of a unique nanophase low density, high strength composite material capable of retaining its superior properties even above the melting point of aluminum.

  12. Nickel adsorption to hydrous ferric oxide in the presence of EDTA: Effects of component addition sequence

    SciTech Connect

    Bryce, A.L.; Kornicker, W.A.; Elzerman, A.W. ); Clark, S.B. )

    1994-12-01

    Nickel, EDTA, and hydrous ferric oxide were combined in different sequences to study the effect on equilibration. In this system, the fraction of nickel adsorbed to the hydrous ferric oxide depended on the component addition sequence, but the fraction of EDTA adsorbed did not. In one sequence, nickel and EDTA were combined to preform a NiEDTA[sup 2[minus

  13. Ferric oxide quantum dots in stable phosphate glass system and their magneto-optical study

    SciTech Connect

    Garaje, Sunil N.; Apte, Sanjay K.; Kumar, Ganpathy; Panmand, Rajendra P.; Naik, Sonali D.; Mahajan, Satish M.; Chand, Ramesh; Kale, Bharat B.

    2013-02-15

    Graphical abstract: We report synthesis of ferric oxide embedded low melting phosphate glass nanocomposite and also the effect of ferric oxide nanoparticles (NCs) content on the optical and magneto-optical properties of the glasses. Faraday rotation of the glass nanocomposites was measured and showed variation in Verdet constant with concentration of ferric oxide. Interestingly, the host glass itself showed fairly good Verdet constant (11.5°/T cm) and there is a threefold enhancement in the Verdet constant of ferric oxide quantum dot-glass nanocomposite. Highlights: ► We synthesize ferric oxide embedded low melting stable phosphate glass nanocomposite. ► Glasses doped with 0.25 and 2% ferric oxide show particle size in the range of 4–12 nm. ► The host phosphate glass itself shows fairly good Verdet constant (11.5°/T cm). ► Glasses doped with 0.25% ferric oxide show high Verdet constant (30.525°/T cm). ► The as synthesis glasses may have potential application in magneto optical devices. -- Abstract: Herein, we report the synthesis of ferric oxide embedded low melting phosphate glass nanocomposite and also the effect of ferric oxide nanoparticles content on the optical and magneto-optical properties of the glasses. The optical study clearly showed red shift in optical cut off with increasing ferric oxide concentration. The band gap of the host glass was observed to be 3.48 eV and it shifted to 3.14 eV after doping with ferric oxide. The glasses doped with 0.25 and 2% ferric oxide showed particle size of 4–6 nm and 8–12 nm, respectively. Faraday rotation of the glass nanocomposites was measured and showed variation in the Verdet constant as per increasing concentration of ferric oxide. Interestingly, the host glass itself showed fairly good Verdet constant (11.5°/T cm) and threefold enhancement was observed in the Verdet constant of ferric oxide quantum dot-glass nanocomposite.

  14. Rapidly reversible redox transformation in nanophase manganese oxides at room temperature triggered by changes in hydration

    PubMed Central

    Birkner, Nancy; Navrotsky, Alexandra

    2014-01-01

    Chemisorption of water onto anhydrous nanophase manganese oxide surfaces promotes rapidly reversible redox phase changes as confirmed by calorimetry, X-ray diffraction, and titration for manganese average oxidation state. Surface reduction of bixbyite (Mn2O3) to hausmannite (Mn3O4) occurs in nanoparticles under conditions where no such reactions are seen or expected on grounds of bulk thermodynamics in coarse-grained materials. Additionally, transformation does not occur on nanosurfaces passivated by at least 2% coverage of what is likely an amorphous manganese oxide layer. The transformation is due to thermodynamic control arising from differences in surface energies of the two phases (Mn2O3 and Mn3O4) under wet and dry conditions. Such reversible and rapid transformation near room temperature may affect the behavior of manganese oxides in technological applications and in geologic and environmental settings. PMID:24733903

  15. Magnetotactic bacteria form magnetite from a phosphate-rich ferric hydroxide via nanometric ferric (oxyhydr)oxide intermediates

    PubMed Central

    Baumgartner, Jens; Morin, Guillaume; Menguy, Nicolas; Perez Gonzalez, Teresa; Widdrat, Marc; Cosmidis, Julie; Faivre, Damien

    2013-01-01

    The iron oxide mineral magnetite (Fe3O4) is produced by various organisms to exploit magnetic and mechanical properties. Magnetotactic bacteria have become one of the best model organisms for studying magnetite biomineralization, as their genomes are sequenced and tools are available for their genetic manipulation. However, the chemical route by which magnetite is formed intracellularly within the so-called magnetosomes has remained a matter of debate. Here we used X-ray absorption spectroscopy at cryogenic temperatures and transmission electron microscopic imaging techniques to chemically characterize and spatially resolve the mechanism of biomineralization in those microorganisms. We show that magnetite forms through phase transformation from a highly disordered phosphate-rich ferric hydroxide phase, consistent with prokaryotic ferritins, via transient nanometric ferric (oxyhydr)oxide intermediates within the magnetosome organelle. This pathway remarkably resembles recent results on synthetic magnetite formation and bears a high similarity to suggested mineralization mechanisms in higher organisms. PMID:23980143

  16. Dietary bioavailability of Cu adsorbed to colloidal hydrous ferric oxide

    USGS Publications Warehouse

    Cain, Daniel J.; Croteau, Marie-Noële; Fuller, Christopher C.

    2013-01-01

    The dietary bioavailability of copper (Cu) adsorbed to synthetic colloidal hydrous ferric oxide (HFO) was evaluated from the assimilation of 65Cu by two benthic grazers, a gastropod and a larval mayfly. HFO was synthesized, labeled with 65Cu to achieve a Cu/Fe ratio comparable to that determined in naturally formed HFO, and then aged. The labeled colloids were mixed with a food source (the diatom Nitzschia palea) to yield dietary 65Cu concentrations ranging from 211 to 2204 nmol/g (dry weight). Animals were pulse fed the contaminated diet and assimilation of 65Cu from HFO was determined following 1–3 days of depuration. Mass transfer of 65Cu from HFO to the diatom was less than 1%, indicating that HFO was the source of 65Cu to the grazers. Estimates of assimilation efficiency indicated that the majority of Cu ingested as HFO was assimilated (values >70%), implying that colloidal HFO potentially represents a source of dietary Cu to benthic grazers, especially where there is active formation and infiltration of these particles into benthic substrates.

  17. RATES OF HYDROUS FERRIC OXIDE CRYSTALLIZATION AND THE INFLUENCE ON COPRECIPITATED ARSENATE: JOURNAL ARTICLE

    EPA Science Inventory

    NRMRL-ADA-02101 Ford*, R. Rates of Hydrous Ferric Oxide Crystallization and the Influence on Coprecipitated Arsenate. Environmental Science & Technology 36 (11):2459-2463 (2002). EPA/600/J-02/240. Arsenate coprecipitated with hydrous fer...

  18. Location of nanophase Fe-oxides in palagonitic soils: Implication for Martian pigments

    NASA Technical Reports Server (NTRS)

    Golden, D. C.; Morris, R. V.; Ming, D. W.; Lauer, H. V., Jr.

    1992-01-01

    Palagonitic materials from Mauna Kea, Hawaii, were identified as Mars analogs based on their spectral and magnetic properties. These materials probably resulted from hydrothermal alteration during eruption of the volcano and/or from weathering under ambient conditions. The reflectance spectra of the Mars surface obtained by Earth-based telescopes and the reflectance spectra of analogs obtained in the laboratory show features due to electronic transitions of Fe(III) in oxide particles that range in size from nanometer (nanophase) to micrometer sized or larger. The presence of Fe(III) suggests oxidizing conditions during the alteration process in Mars that may have occurred in the past or during a slow ongoing process. Two naturally altered basaltic samples from Hawaii (HWMK12 and HWMK13) and a laboratory-altered (PH-13-DCGT2) basaltic glass similar in elemental composition to the above two samples was examined. All three samples exhibited spectral characteristics similar to martian bright-region spectra. Chemical and mineralogical changes occurring at the surface of these basalts were studied in order to understand the basis for their Mars-like properties. The spectral properties of the three samples were examined after the removal of Fe oxides by chemical extractants.

  19. Interaction of nanoparticles of ferric oxide with brain nerve terminals and blood platelets

    NASA Astrophysics Data System (ADS)

    Borisova, Tatiana; Krisanova, Natalia; Sivko, Roman; Borisov, Arseniy

    2012-07-01

    Nanoparticles of ferric oxide are the components of Lunar and Martian soil simulants. The observations suggest that exposure to Lunar soli simulant can be deleterious to human physiology and the components of lunar soil may be internalized by lung epithelium and may overcome the blood-brain barrier. The study focused on the effects of nanoparticles of ferric oxide on the functional state of rat brain nerve terminals (synaptosomes) and rabbit blood platelets. Using photon correlation spectroscopy, we demonstrated the binding of nanoparticles of ferric oxide with nerve terminals and platelets. Nanoparticles did not depolarize the plasma membrane of nerve terminals and platelets that was shown by fluorimetry with potential-sensitive fluorescent dye rhodamine 6G. Using pH-sensitive fluorescent dye acridine orange, we revealed that the acidification of synaptic vesicles of nerve terminals and secretory granules of platelets did not change in the presence of nanoparticles. The initial velocity of uptake of excitatory neurotransmitter glutamate was not influenced by nanoparticles of ferric oxide, whereas glutamate binding to nerve terminals was altered. Thus, it was suggested that nanoparticles of ferric oxide might disturb glutamate transport in the mammalian CNS.

  20. RATES OF HYDROUS FERRIC OXIDE CRYSTALLIZATION AND THE INFLUENCE ON COPRECIPITATED ARSENATE

    EPA Science Inventory

    Arsenate coprecipitated with hydrous ferric oxide (HFO) was stabilized against dissolution during transformation of HFO to more crystalline iron (hydr)oxides. The rate of arsenate stabilization approximately coincided with the rate of HFO transformation at pH 6 and 40 ?C. Compa...

  1. The formation of magnetic ferric oxides in soils over underground gas storage reservoirs

    NASA Astrophysics Data System (ADS)

    Mozharova, N. V.; Pronina, V. V.; Ivanov, A. V.; Shoba, S. A.; Zagurskii, A. M.

    2007-06-01

    The concepts of the specific mechanisms responsible for the formation of magnetic ferric oxides in soils over artificial gas storage reservoirs are considered for the first time. Upon the interaction of technogenic allochthonous methane with soil, some biogeochemical barriers are formed that are characterized by the accumulation of solid products resulting from the functioning and development of the soil. The pedogenic new formations are represented by fine magnetic ferric oxides of specific shape. They are the result of an elementary soil-forming processoxidogenesis composed of a complex of microprocesses of biogenic and abiogenic nature.

  2. A Ferric-Peroxo Intermediate in the Oxidation of Heme by IsdI.

    PubMed

    Takayama, Shin-Ichi J; Loutet, Slade A; Mauk, A Grant; Murphy, Michael E P

    2015-04-28

    The canonical heme oxygenases (HOs) catalyze heme oxidation via a heme-bound hydroperoxo intermediate that is stabilized by a water cluster at the active site of the enzyme. In contrast, the hydrophobic active site of IsdI, a heme-degrading enzyme from Staphylococcus aureus, lacks a water cluster and is expected to oxidize heme by an alternative mechanism. Reaction of the IsdI-heme complex with either H2O2 or m-chloroperoxybenzoic acid fails to produce a specific oxidized heme iron intermediate, suggesting that ferric-hydroperoxo or ferryl derivatives of IsdI are not involved in the catalytic mechanism of this enzyme. IsdI lacks a proton-donating group in the distal heme pocket, so the possible involvement of a ferric-peroxo intermediate has been evaluated. Density functional theory (DFT) calculations indicate that heme oxidation involving a ferric-peroxo intermediate is energetically accessible, whereas the energy barrier for a reaction involving a ferric-hydroperoxo intermediate is too great in the absence of a proton donor. We propose that IsdI catalyzes heme oxidation through nucleophilic attack by the heme-bound peroxo species. This proposal is consistent with our previous demonstration by nuclear magnetic resonance spectroscopy that heme ruffling increases the susceptibility of the meso-carbon of heme to nucleophilic attack. PMID:25853501

  3. Complexation of ferric oxide particles with pectins of ordered and random distribution of charged units

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Complexation between ferric oxide particles and pectins with degree of methylation 50%, but having blockwise (ordered) or random arrangement of free carboxyl groups, are investigated by electric light scattering and electrophoresis. The influence of charge distribution in pectin chain on the electri...

  4. The biostimulation of anaerobic digestion with (semi)conductive ferric oxides: their potential for enhanced biomethanation.

    PubMed

    Baek, Gahyun; Kim, Jaai; Cho, Kyungjin; Bae, Hyokwan; Lee, Changsoo

    2015-12-01

    The effect of biostimulation with ferric oxides, semiconductive ferric oxyhydroxide, and conductive magnetite on the anaerobic digestion of dairy wastewater was examined in a batch mode. The reactors supplemented with ferric oxyhydroxide (R2) and magnetite (R3) showed significantly enhanced biomethanation performance compared with the control (R1). The removal of chemical oxygen demand (COD) after 30 days was 31.9, 59.3, and 82.5% in R1, R2, and R3, respectively. The consumed COD was almost fully recovered as biogas in R2 and R3, while only 79% was recovered in R1. The total energy production as biogas was accordingly 32.2, 71.0, and 97.7 kJ in R1, R2, and R3, respectively. The reactors also differed in the acid formation profile with more propionate and butyrate found in R1 and more acetate found in R3. The enhanced biomethanation seems to be associated with variations in the bacterial community structure supposedly induced by the ferric oxides added. In contrast, no evident variation was observed in the archaeal community structure among the reactors. The potential electric syntrophy formed between Methanosaeta concilii-like methanogens and electroactive iron-reducing bacteria, particularly Trichococcus, was likely responsible for the enhanced performance. The stimulated growth of fermentative iron reducers may also have contributed by altering the metabolic characteristics of the bacterial communities to produce more favorable acidogenic products for methanogenesis. The overall results suggest the potential of biostimulation with (semi)conductive ferric oxides to enhance the rate and efficiency of the biomethanation of organic wastes. This seems to be potentially attractive, as increasing attention is being paid to the energy self-sufficiency of waste/wastewater treatment processes today. PMID:26272096

  5. Charge-coupled device imaging spectroscopy of Mars. II - Results and implications for Martian ferric mineralogy

    NASA Technical Reports Server (NTRS)

    Bell, James F., III

    1992-01-01

    Materials similar to nanophase ferric oxides are presently seen to dominate the spectral behavior of the Martian surface in the visible-to-near-IR, in view of imaging spectroscopic observations of Mars. Attention is accordingly given to models for the formation of hematite and other ferric minerals in both current terrestrial environments and in the current and past, possibly wetter Martian climate. It is noted that imaging spectroscopy is an ideal tool for high spatial resolution spacecraft and telescopic studies of the Martian surface.

  6. A combined treatment of landfill leachate using calcium oxide, ferric chloride and clinoptilolite.

    PubMed

    Orescanin, Visnja; Ruk, Damir; Kollar, Robert; Mikelic, Ivanka Lovrencic; Nad, Karlo; Mikulic, Nenad

    2011-01-01

    The aim of this research was development of appropriate procedure for treatment of landfill leachate taken from old sanitary landfill Piskornica (Koprivnica, Croatia). Due to complex nature of the effluent a combined treatment approach was applied. Samples were treated with calcium oxide followed by ferric chloride and finally with clinoptilolite. The optimum amount of treating agents and contact time were determined. Application of calcium oxide (25 g/L, 20 min. contact time) resulted in the reduction of color, turbidity, suspended solids and ammonia for 94.50%, 96.55%, 95.66% and 21.60%, respectively, while the removal efficiency of Cr (VI), Fe, Ni, Cu, Zn and Pb was 75.00%, 95.34%, 56.52%, 78.72%, 73.02% and 100.00%, respectively. After addition of ferric chloride (570 mg Fe(3+)/L, 20 min. contact time) removal efficiency of color, turbidity, suspended solids and ammonia increased to 96.04%, 99.27%, 98.61%, and 43.20%, respectively. Removal of ammonia (81.60%) increased significantly after final adsorption onto clinoptilolite (25 g/L, 4 h contact time). Removal of COD after successive treatment with calcium oxide, ferric chloride and clinoptilolite was 64.70%, 77.40% and 81.00%, respectively. PMID:21308604

  7. Energetic basis of catalytic activity of layered nanophase calcium manganese oxides for water oxidation

    PubMed Central

    Birkner, Nancy; Nayeri, Sara; Pashaei, Babak; Najafpour, Mohammad Mahdi; Casey, William H.; Navrotsky, Alexandra

    2013-01-01

    Previous measurements show that calcium manganese oxide nanoparticles are better water oxidation catalysts than binary manganese oxides (Mn3O4, Mn2O3, and MnO2). The probable reasons for such enhancement involve a combination of factors: The calcium manganese oxide materials have a layered structure with considerable thermodynamic stability and a high surface area, their low surface energy suggests relatively loose binding of H2O on the internal and external surfaces, and they possess mixed-valent manganese with internal oxidation enthalpy independent of the Mn3+/Mn4+ ratio and much smaller in magnitude than the Mn2O3-MnO2 couple. These factors enhance catalytic ability by providing easy access for solutes and water to active sites and facile electron transfer between manganese in different oxidation states. PMID:23667149

  8. Graphene oxide/ferric hydroxide composites for efficient arsenate removal from drinking water.

    PubMed

    Zhang, Kai; Dwivedi, Vineet; Chi, Chunyan; Wu, Jishan

    2010-10-15

    A series of novel composites based on graphene oxide (GO) cross-linked with ferric hydroxide was developed for effective removal of arsenate from contaminated drinking water. GO, which was used as a supporting matrix here, was firstly treated with ferrous sulfate. Then, the ferrous compound cross-linked with GO was in situ oxidized to ferric compound by hydrogen peroxide, followed by treating with ammonium hydroxide. The morphology and composition of the composites were analyzed by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The ferric hydroxide was found to be homogenously impregnated onto GO sheets in amorphous form. These composites were evaluated as absorbents for arsenate removal from contaminated drinking water. For the water with arsenate concentration at 51.14 ppm, more than 95% of arsenate was absorbed by composite GO-Fe-5 with an absorption capacity of 23.78 mg arsenate/g of composite. Effective arsenate removal occurred in a wide range of pH from 4 to 9. However, the efficiency of arsenate removal was decreased when pH was increased to higher than 8. PMID:20580161

  9. The mechanism of selenate adsorption on goethite and hydrous ferric oxide

    SciTech Connect

    Manceau, A.; Charlet, L. . Environmental Geochemistry Group)

    1994-11-01

    Sorption of anions on mineral surfaces, and specifically on Fe oxides, is a topic of continued interest in soil and environmental chemistry. EXAFS spectroscopy has been used to investigate the structure of selenate surface complexes sorbed on dry and wet goethite and hydrous ferric oxide. It is shown that selenate oxyanions always form inner-sphere surface complexes on both sorbents regardless of the hydration state. Selenate, like phosphate and selenite, forms binuclear bridging complexes on (hk0) planes with two singly coordinated A-type OH groups. Furthermore evidence is provided for the attachment of selenate oxyanions on (001) planes by the sharing of edges with Fe octahedra. Selenite and arsenate appear to form the same types of surface complexes as selenate at the surface of goethite and hydrous ferric oxide. It is likely that this sorption mechanism is operative for other anions including phosphate and sulfate. A consequence of this study is the conclusion that the crystallographic planes of Fe oxides (hk0 and 001) do not appear to selectivity bond either cations or anions, at least at high surface coverage.

  10. The fate of iron on Mars: Mechanism of oxidation of basaltic minerals to ferric-bearing assemblages

    NASA Technical Reports Server (NTRS)

    Burns, Roger G.

    1992-01-01

    Perhaps the most conspicuous indication that chemical weathering has occurred on the surface of Mars is the overall color of the red planet and the spectroscopic features that identify ferric-bearing assemblages in the martian regolith. Apparently, Fe(2+) ions in primary minerals in parent igneous rocks on the martian surface have been oxidized to ferric iron, which occurs in degradation products that now constitute the regolith. The mineralogy of the unweathered igneous rocks prior to weathering on the martian surface is reasonably well constrained, mainly as a result of petrographic studies of the SNC meteorites. However, the alteration products resulting from oxidative weathering of these rocks are less well-constrained. The topics covered include the following: primary rocks subjected to chemical weathering; dissolution processes; oxidation of dissolved Fe(2+); mechanism of polymerization of hydrous ferric oxides; terrestrial occurrences of ferromagnesian smectites; and dehydroxylated Mg-Fe smectites on Mars.

  11. The Ferric Mineralogy of Mars

    NASA Astrophysics Data System (ADS)

    Bell, James F., III

    1992-12-01

    This dissertation presents the results of new telescope observations of Mars using the technique of imaging spectroscopy. Data at high spectral resolution (lambda/delta-lambda=350) and at the best possible spatial resolution from Earth (80-150 km) were obtained from Mauna Kea Observatory during the 1988 perihelic opposition. Spectra in the 0.4-0.8 micron region reveal distinct absorption features and spectral slope changes that are characteristic of Fe^3+ bearing minerals. Poorly crystalline materials, similar perhaps to nanophase ferric minerals or palagonitelike weathering products of basaltic glass, dominate the spectral behavior of the Martian surface in the visible to near IR. Analysis of absorption-band shapes and positions and the character of the strong near-UV ferric absorption edge provides solid evidence for the detection of minor amounts (4-8%) of crystalline hematite (alpha-Fe2O3) on Mars. While there is no unique evidence in the 0.40-0.95 micron region for the existence of other ferric oxides/oxyhydroxides, Fe-rich clays, or ferric sulfates, in these new data or in previous spacecraft and telescopic data, the existence of these and other ferric-bearing phases (e.g., goethite, jarosite, ferrihydrite, feroxyhite, maghemite) cannot be unequivocally ruled out, partly because of the spectral masking effects of hematite. Different models for the formation of hematite and other ferric minerals in various terrestrial analog environments and in the current and possibly past warmer, wetter Martian climate are discussed. Images in the 0.4-1.0 micron region reveal the ``classical'' albedo features at red and green wavelengths (lambda > 0.5 microns) and show a spectrally bland surface dominated by polar ices and atmospheric condensates at blue wavelengths. A number of differnet telescopic laboratory data analysis techniques are used to show that (1) the 2%-5% deep 0.6-0.7 micron ferric absorption bands varies across the surface at the 1%-2% level, with bright regions typically having a deeper band; (2) many dark regions and a few isolated bright regions are perhaps more spectrally hteterogeneous than once thought; (3) 95% of the variance in Mars spectra can be modeled using two endmembers (classical bright and dark regions), but there are distinct spatially coherent units within the remaining 5% of the variance that correlate with ices, condensates, and/or dark, ferric-rich materials; (4) numerous ferric minerals have absorption features in the 0.9-1.0 micron region, and the weak bands observed in previous Mars spectra at these wavelengths that have been ascribed entirely to Fe^2+ minerals may, within the limits of the available data, also be consistent with variations in Fe^3+ mineralogy. The advantages of imaging spectroscopy over traditional point spectroscopy or broadband filter imaging make it an ideal tool for high spatial-resolution spacecraft studies of the Martian surface. (SECTION: Dissertation Abstracts)

  12. Uranium Extraction From Laboratory Synthesized, Uranium-Doped Hydrous Ferric Oxides

    SciTech Connect

    Smith, Steven C.; Douglas, Matthew; Moore, Dean A.; Kukkadapu, Ravi K.; Arey, Bruce W.

    2009-03-01

    The extractability of uranium (U) from synthetic hydrous ferric oxides has been shown to decrease as a function of mineral ripening, consistent with the hypothesis that the ripening process decrease contaminant lability. To evaluate this process, three hydrous ferric oxide (HFO) suspensions were co-precipitated with uranyl (UO22+) and maintained at pH 7.0 0.1. Uranyl was added to the HFO post-precipitation in a fourth suspension. Two suspensions also contained either co-precipitated silicate (Si-U-HFO) or phosphate (P-U-HFO). After precipitation of the HFOs, at time intervals of one week, one month, six months, one year, and 2 years, aliquots of the suspensions were contacted with five solutions for a range of time. The extracts were analyzed for U and iron (Fe). The results are consistent with the hypothesis that U and Fe extractability will decrease as the mineral phase ripens. All extracting solutions exhibited some degree of selectivity for U, as the proportional extraction of U exceeded that for congruent dissolution. Micro X-ray diffraction analysis indicates the transformation from an amorphous phase to a material containing substantial proportions of crystalline goethite and hematite, except the P-U-HFO which remained primarily amorphous. Further analysis of the co-precipitates by the Mssbauer technique and scanning electron microscopy (SEM) provides further evidence of mineralogic ripening

  13. Arsenic and antimony removal from drinking water by adsorption on granular ferric oxide.

    PubMed

    Sazakli, Eleni; Zouvelou, Stavroula V; Kalavrouziotis, Ioannis; Leotsinidis, Michalis

    2015-01-01

    Arsenic and antimony occur in drinking water due to natural weathering or anthropogenic activities. There has been growing concern about their impact on health. The aim of this study was to assess the efficiency of a granular ferric oxide adsorbent medium to remove arsenic and antimony from drinking water via rapid small-scale column tests (RSSCTs). Three different water matrices - deionized, raw water treated with a reverse osmosis domestic device and raw water - were spiked with arsenic and/or antimony to a concentration of 100 ?g L?. Both elements were successfully adsorbed onto the medium. The loadings until the guideline value was exceeded in the effluent were found to be 0.35-1.63 mg g? for arsenic and 0.12-2.11 mg g? for antimony, depending on the water matrix. Adsorption of one element was not substantially affected by the presence of the other. Aeration did not affect significantly the adsorption capacity. Granular ferric oxide could be employed for the simultaneous removal of arsenic and antimony from drinking water, whereas full-scale systems should be assessed via laboratory tests before their implementation. PMID:25746656

  14. Moessbauer search for ferric oxide phases in lunar materials and simulated lunar materials

    NASA Technical Reports Server (NTRS)

    Forester, D. W.

    1973-01-01

    Moessbauer studies were carried out on lunar fines and on simulated lunar glasses containing magnetic-like precipitates with the primary objective of determining how much, if any, ferric oxide is present in the lunar soils. Although unambiguous evidence of lunar Fe(3+) phases was not obtained, an upper limit was estimated from different portions of the Moessbauer spectra to be between 0.1 and 0.4 wt.% (as Fe3O4). A smaller than 62 microns fraction of 15021,118 showed 0.5 wt.% ferromagnetic iron at 300 K in as-returned condition. After heating to 650 C in an evacuated, sealed quartz tube for 1400 hours, the same sample exhibited 1 wt.% ferromagnetic iron at room temperature. An accompanying decrease in excess absorption area near zero velocity was noted. Thus, the result of the vacuum heat treatment was to convert fine grained iron to larger particles, apparently without the oxidation effects commonly reported.

  15. Hydrous ferric oxide precipitation in the presence of nonmetabolizing bacteria: Constraints on the mechanism of a biotic effect

    NASA Astrophysics Data System (ADS)

    Rancourt, Denis G.; Thibault, Pierre-Jean; Mavrocordatos, Denis; Lamarche, Gilles

    2005-02-01

    We have used room temperature and cryogenic 57Fe Mssbauer spectroscopy, powder X-ray diffraction (pXRD), mineral magnetometry, and transmission electron microscopy (TEM), to study the synthetic precipitation of hydrous ferric oxides (HFOs) prepared either in the absence (abiotic, a-HFO) or presence (biotic, b-HFO) of nonmetabolizing bacterial cells ( Bacillus subtilis or Bacillus licheniformis, 10 8 cells/mL) and under otherwise identical chemical conditions, starting from Fe(II) (10 -2, 10 -3, or 10 -4 mol/L) under open oxic conditions and at different pH (6-9). We have also performed the first Mssbauer spectroscopy measurements of bacterial cell wall ( Bacillus subtilis) surface complexed Fe, where Fe(III) (10 -3.5-10 -4.5 mol/L) was added to a fixed concentration of cells (10 8 cells/mL) under open oxic conditions and at various pH (2.5-4.3). We find that non-metabolic bacterial cell wall surface complexation of Fe is not passive in that it affects Fe speciation in at least two ways: (1) it can reduce Fe(III) to sorbed-Fe 2+ by a proposed steric and charge transfer effect and (2) it stabilizes Fe(II) as sorbed-Fe 2+ against ambient oxidation. The cell wall sorption of Fe occurs in a manner that is not compatible with incorporation into the HFO structure (different coordination environment and stabilization of the ferrous state) and the cell wall-sorbed Fe is not chemically bonded to the HFO particle when they coexist (the sorbed Fe is not magnetically polarized by the HFO particle in its magnetically ordered state). This invalidates the concept that sorption is the first step in a heterogeneous nucleation of HFO onto bacterial cell walls. Both the a-HFOs and the b-HFOs are predominantly varieties of ferrihydrite (Fh), often containing admixtures of nanophase lepidocrocite (nLp), yet they show significant abiotic/biotic differences: Biotic Fh has less intraparticle (including surface region) atomic order (Mssbauer quadrupole splitting), smaller primary particle size (magnetometry blocking temperature), weaker Fe to particle bond strength (Mssbauer center shift), and no six-line Fh (6L-Fh) admixture (pXRD, magnetometry). Contrary to current belief, we find that 6L-Fh appears to be precipitated directly, under a-HFO conditions, from either Fe(II) or Fe(III), and depending on Fe concentration and pH, whereas the presence of bacteria disables all such 6L-Fh precipitation and produces two-line Fh (2L-Fh)-like biotic coprecipitates. Given the nature of the differences between a-HFO and b-HFO and their synthesis condition dependences, several biotic precipitation mechanisms (template effect, near-cell environment effect, catalyzed nucleation and/or growth effect, and substrate-based coprecipitation) are ruled out. The prevailing present view of a template or heterogeneous nucleation barrier reduction effect, in particular, is shown not to be the cause of the large observed biotic effects on the resulting HFOs. The only proposed mechanism (relevant to Fh) that is consistent with all our observations is coprecipitation with and possible surface poisoning by ancillary bacteriagenic compounds. That bacterial cell wall functional groups are redox active and the characteristics of biotic (i.e., natural) HFOs compared to those of abiotic (i.e., synthetic) HFOs have several possible biogeochemical implications regarding Fe cycling, in the photic zones of water columns in particular.

  16. Novel regeneration method for phosphate loaded granular ferric (hydr)oxide--a contribution to phosphorus recycling.

    PubMed

    Kunaschk, Marco; Schmalz, Viktor; Dietrich, Norman; Dittmar, Thomas; Worch, Eckhard

    2015-03-15

    At a progressive rate, small wastewater treatment plants in rural areas need to be equipped with an additional phosphorus removal stage in order to achieve a good chemical status in the receiving natural water bodies. A conventional regeneration method for ferric (hydr)oxides such as phosphate specific adsorbents, which can be applied to remove and recover phosphorus in fixed bed filters, was investigated and improved. It was shown that a loss of up to 85% of the initial capacity can be observed when regeneration with 1 M NaOH is implemented. The losses are caused by surface blocking with different calcium-containing compounds as revealed by an EDX analysis. These blocking compounds could be removed completely with an additional acidic regeneration step at pH = 2.5. During the alkaline desorption that followed, complete phosphorus removal and a full recovery of the adsorption capacity were achieved for goethite-rich Bayoxide(®) E 33 HC (E33HC) and akaganéite-rich GEH(®) 104 (GEH). The regeneration procedure was repeated up to eight times without any signs of further decline in the phosphate adsorption capacity or any changes in the specific surface area or pore size distribution of the adsorbent. In contrast to GEH and E33HC, ferric hydroxide- and calcite-rich FerroSorp(®) Plus (FSP) was partly dissolved during acid treatment. PMID:25618522

  17. In situ monitoring magnetism and resistance of nanophase platinum upon electrochemical oxidation

    PubMed Central

    Steyskal, Eva-Maria; Topolovec, Stefan; Landgraf, Stephan; Krenn, Heinz

    2013-01-01

    Summary Controlled tuning of material properties by external stimuli represents one of the major topics of current research in the field of functional materials. Electrochemically induced property tuning has recently emerged as a promising pathway in this direction making use of nanophase materials with a high fraction of electrode-electrolyte interfaces. The present letter reports on electrochemical property tuning of porous nanocrystalline Pt. Deeper insight into the underlying processes could be gained by means of a direct comparison of the charge-induced response of two different properties, namely electrical resistance and magnetic moment. For this purpose, four-point resistance measurements and SQUID magnetometry were performed under identical in situ electrochemical control focussing on the regime of electrooxidation. Fully reversible variations of the electrical resistance and the magnetic moment of 6% and 1% were observed upon the formation or dissolution of a subatomic chemisorbed oxygen surface layer, respectively. The increase of the resistance, which is directly correlated to the amount of deposited oxygen, is considered to be primarily caused by charge-carrier scattering processes at the metalelectrolyte interfaces. In comparison, the decrease of the magnetic moment upon positive charging appears to be governed by the electric field at the nanocrystalliteelectrolyte interfaces due to spinorbit coupling. PMID:23844345

  18. Enhanced dark hydrogen fermentation by addition of ferric oxide nanoparticles using Enterobacter aerogenes.

    PubMed

    Lin, Richen; Cheng, Jun; Ding, Lingkan; Song, Wenlu; Liu, Min; Zhou, Junhu; Cen, Kefa

    2016-05-01

    Ferric oxide nanoparticles (FONPs) were used to facilitate dark hydrogen fermentation using Enterobacter aerogenes. The hydrogen yield of glucose increased from 164.5±2.29 to 192.4±1.14mL/g when FONPs concentration increased from 0 to 200mg/L. SEM images of E. aerogenes demonstrated the existence of bacterial nanowire among cells, suggesting FONPs served as electron conduits to enhance electron transfer. TEM showed cellular internalization of FONPs, indicating hydrogenase synthesis and activity was potentially promoted due to the released iron element. When further increasing FONPs concentration to 400mg/L, the hydrogen yield of glucose decreased to 147.2±2.54mL/g. Soluble metabolic products revealed FONPs enhanced acetate pathway of hydrogen production, but weakened ethanol pathway. This shift of metabolic pathways allowed more nicotinamide adenine dinucleotide for reducing proton to hydrogen. PMID:26890796

  19. Magnetic ordering of ferric oxide within SiO{sub 2}-based mesoporous materials

    SciTech Connect

    Guo Haiquan; Zhang Xiaoming; Cui Minhui; Sharma, Renu; Yang Nanloh; Akins, Daniel L. . E-mail: akins@sci.ccny.cuny.edu

    2005-10-06

    Nanostructural ferric oxide was encapsulated within one-dimensional (1-D) silicate mesoporous molecular materials, resulting in the formation of nanocomposites. The resulting nanocomposites were characterized by UV-vis, IR, TEM, EPR and X-ray diffraction. The occluded Fe{sub 2}O{sub 3} nanostructures were found to evince optical spectra and magnetic properties that were significantly different from that of bulk Fe{sub 2}O{sub 3}. EPR measurements indicate that the various nanocomposites (whose dimensions were controllable by the pore sizes of the silicate materials), when sufficiently loaded with small Fe{sub 2}O{sub 3} nanoparticles, possess nonzero absorptions at zero applied magnetic field, as well as significant microwave absorption capacities as a function of applied magnetic field strength.

  20. Boat pressure washing wastewater treatment with calcium oxide and/or ferric chloride.

    PubMed

    Ore?anin, Vinja; Kollar, Robert; Na?, Karlo; Mikeli?, Ivanka Lovren?i?; Mikuli?, Nenad

    2012-03-01

    The aim of this study was to investigate the efficiency of (1) chemical precipitation by calcium oxide, (2) coagulation/flocculation by ferric chloride (FC), and (3) the combination these two methods in reducing the toxicity of wastewater generated by boat pressure washing. All three methods gave satisfactory results in the removal of colour, turbidity, Cr, Fe, Cu, Zn, and Pb. The concentrations of heavy metals were lowered below national limits with 1 g of CaO, 2.54 mg of Fe3+ in the form of FeCl3x6H2O, and the combination of 0.25 g of CaO and 5.08 mg of Fe3+ per 50 mL of wastewater. Both CaO (1.50 g per 50 mL of wastewater) and FC proved efficient, but their combination yielded a significantly better performance: 99.41 %, 100.00 %, 97.87 %, 99.09 %, 99.90 %, 99.46 % and 98.33 % for colour, turbidity, Cr, Fe, Cu, Zn, and Pb respectively. For colour, Cr, Cu, Zn, and Pb removal efficiencies increased in the following order: FCoxide followed by ferric chloride is efficient, cost-effective, and user-friendly. PMID:22450202

  1. Preloading hydrous ferric oxide into granular activated carbon for arsenic removal.

    PubMed

    Jang, Min; Chen, Weifang; Cannon, Fred S

    2008-05-01

    Arsenic is of concern in water treatment because of its health effects. This research focused on incorporating hydrous ferric oxide (HFO) into granular activated carbon (GAC) for the purpose of arsenic removal. Iron was incorporated into GAC via incipient wetness impregnation and cured at temperatures ranging from 60 to 90 degrees C. X-ray diffractions and arsenic sorption as a function of pH were conducted to investigate the effect of temperature on final iron oxide (hydroxide) and their arsenic removal capabilities. Results revealed that when curing at 60 degrees C, the procedure successfully created HFO in the pores of GAC, whereas at temperatures of 80 and 90 degrees C, the impregnated iron oxide manifested a more crystalline form. In the column tests using synthetic water, the HFO-loaded GAC prepared at 60 degrees C also showed higher sorption capacities than media cured at higher temperatures. These results indicated that the adsorption capacity for arsenic was closely related to the form of iron (hydr)oxide for a given iron content For the column test using a natural groundwater, HFO-loaded GAC (Fe, 11.7%) showed an arsenic sorption capacity of 26 mg As/g when the influent contained 300 microg/L As. Thus, the preloading of HFO into a stable GAC media offered the opportunity to employ fixed carbon bed reactors in water treatment plants or point-of-use filters for arsenic removal. PMID:18522120

  2. Formation of Green Rust and Immobilization of Nickel in Response to Bacterial Reduction of Hydrous Ferric Oxide

    SciTech Connect

    Parmar, N.; Gorby, Yuri A.; Beveridge, Terrance J.; Ferris, F G.

    2001-04-01

    This investigation documents the formation of Green Rust (GR) and immobilization of Ni2+ in response to bacterial reduction of hydrous ferric oxide (HFO) reduction experiments provided evidence that the solid-phase partitioning of Ni2+ in GR extended from equilibrium solid-solution behavior.

  3. Ameliorative effect of butylated hydroxyanisole against ferric nitrilotriacetate-induced hepatotoxicity and oxidative stress in rats.

    PubMed

    Ansar, S; Iqbal, M

    2015-11-01

    Ferric nitrilotriacetate (Fe-NTA) is a known renal carcinogen and has been shown to adversely induce oxidative stress and tissue toxicity after both acute and chronic exposure. Present studies were designed to study the hepatoprotective and antioxidant potential of butylated hydroxyanisole (BHA), a phenolic antioxidant used in foods on ferric nitrilotriacetate (Fe-NTA) induced hepatotoxicity in rats. Male albino rats of Wistar strain (4-6 weeks old) weighing 125-150 g were used in this study. Animals were given a single dose of Fe-NTA (9 mg/kg body weight, intraperitoneal) after a week's treatment with BHA. BHA was administered orally once daily for 7 days at doses of 1 and 2 mg/animal/day. The hepatoprotective activity was assessed using various biochemical parameters as serum transaminases (alanine transaminase (ALT), aspartate transaminase (AST)) and lactate dehydrogenase (LDH). Fe-NTA treatment increased ALT, AST, and LDH levels significantly when compared to the corresponding saline-treated group (p < 0.001). Fe-NTA also depleted the levels of glutathione and the activities of antioxidant enzymes namely glutathione reductase and glutathione-S-tranferase (p < 0.05). Pretreatment with BHA significantly decreased ALT, AST and LDH levels in a dose-dependent manner (p < 0.05). BHA also increased antioxidant enzymes level and decreased lipid peroxidation and hydrogen peroxide generation to 1.3-1.5-fold as compared to Fe-NTA-treated group. The results show the strong hepatoprotective activity of BHA which could be due to its potent antioxidant effects. PMID:26499990

  4. Hydrous ferric oxide doped alginate beads for fluoride removal: Adsorption kinetics and equilibrium studies

    NASA Astrophysics Data System (ADS)

    Sujana, M. G.; Mishra, A.; Acharya, B. C.

    2013-04-01

    A new biopolymer beads, composite of hydrous ferric oxide (HFO) and alginate were synthesised, characterised and studied for its fluoride efficiency from water. The beads were characterised by chemical analysis, BET surface area, pHPZC and X-ray diffraction (XRD) analysis. The optimum conditions for fluoride removal were determined by studying operational variables viz. pH, contact time, initial F- concentration, bead dose and temperature. Presence of other anions like SO42-, PO43-, NO3-, Cl- and HCO3- effect on fluoride removal efficiency of prepared beads was also tested. The beads were 0.8-0.9 mm in size and contain 32-33% Fe (III) and showed specific surface area of 25.80 m2 g-1 and pHPZC of 5.15. Modified beads demonstrated Langmuir F- adsorption capacity of 8.90 mg g-1 at pH 7.0. The adsorption kinetics were best described by the pseudo-second order kinetic model followed by intra-particle diffusion as the rate determining step. It was found that about 80% of the adsorbed fluoride could be desorbed by using 0.05 M HCl. The FTIR, Raman and SEM-EDAX analysis were used to study the fluoride adsorption mechanisms on beads. Studies were also conducted to test the potential application of beads for F- removal from drinking water and the treated water quality.

  5. ATR-FTIR spectroscopic studies of boric acid adsorption on hydrous ferric oxide

    NASA Astrophysics Data System (ADS)

    Peak, Derek; Luther, George W.; Sparks, Donald L.

    2003-07-01

    Boron is an important micronutrient for plants, but high B levels in soils are often responsible for toxicity effects in plants. It is therefore important to understand reactions that may affect B availability in soils. In this study, Attenuated Total Reflectance Fourier transform Infrared (ATR-FTIR) spectroscopy was employed to investigate mechanisms of boric acid (B(OH) 3) and borate (B(OH) 4-) adsorption on hydrous ferric oxide (HFO). On the HFO surface, boric acid adsorbs via both physical adsorption (outer-sphere) and ligand exchange (inner-sphere) reactions. Both trigonal (boric acid) and tetrahedral (borate) boron are complexed on the HFO surface, and a mechanism where trigonal boric acid in solution reacts to form either trigonal or tetrahedral surface complexes is proposed based upon the spectroscopic results. The presence of outer-sphere boric acid complexes can be explained based on the Lewis acidity of the B metal center, and this complex has important implications for boron transport and availability. Outer-sphere boric acid is more likely to leach downward in soils in response to water flow. Outer-sphere boron would also be expected to be more available for plant uptake than more strongly bound boron complexes, and may more readily return to the soil solution when solution concentrations decrease.

  6. The effect of solids residence time on phosphorus adsorption to hydrous ferric oxide floc.

    PubMed

    Conidi, Daniela; Parker, Wayne J

    2015-11-01

    The impact of solids residence time (SRT) on phosphate adsorption to hydrous ferric oxide (HFO) floc when striving for ultra-low P concentrations was characterized and an equilibrium model that describes the adsorption of P onto HFO floc of different ages was developed. The results showed that fresh HFO had a higher adsorption capacity in comparison to aged (2.8, 7.4, 10.8 and 22.8 days) HFO and contributed substantially to P removal at steady state. P adsorption onto HFO solids was determined to be best described by the Freundlich isotherm. P desorption from HFO solids was negligible supporting the hypothesis that chemisorption is the mechanism of P adsorption on HFO solids. A model that included the contribution of different classes of HFO solids (i.e. High, Low or Old, containing high concentration, low concentration or no active surface sites, respectively) to adsorption onto HFO from a sequencing batch reactor (SBR) system was found to adequately describe P adsorption onto HFO solids of different ages. From the model it was determined that the fractions of High and Low HFO decreased with SRT while the fraction of Old HFO increased with SRT. The transformation of High HFO to Low HFO did not limit the overall production of Old HFO and the fresh HFO solids contributed more to P removal at steady state than the aged solids. PMID:26265079

  7. Defect Clustering and Nano-phase Structure Characterization of Multicomponent Rare Earth-Oxide-Doped Zirconia-Yttria Thermal Barrier Coatings

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming; Chen, Yuan L.; Miller, Robert A.

    2004-01-01

    Advanced thermal barrier coatings (TBCs) have been developed by incorporating multicomponent rare earth oxide dopants into zirconia-based thermal barrier coatings to promote the creation of the thermodynamically stable, immobile oxide defect clusters and/or nanophases within the coating systems. In this paper, the defect clusters, induced by Nd, Gd, and Yb rare earth dopants in the zirconia-yttria thermal barrier coatings, were characterized by high-resolution transmission electron microscopy (TEM). The TEM lattice imaging, selected area diffraction (SAD), and electron energy-loss spectroscopy (EELS) analyses demonstrated that the extensive nanoscale rare earth dopant segregation exists in the plasma-sprayed and electron-physical-vapor-deposited (EB PVD) thermal barrier coatings. The nanoscale concentration heterogeneity and the resulting large lattice distortion promoted the formation of parallel and rotational defective lattice clusters in the coating systems. The presence of the 5-to 100-nm-sized defect clusters and nanophases is believed to be responsible for the significant reduction of thermal conductivity, improved sintering resistance, and long-term high temperature stability of the advanced thermal barrier coating systems.

  8. The kinetics of the oxidation of pyrite by ferric ions and dissolved oxygen: An electrochemical study

    SciTech Connect

    Holmes, P.R.; Crundwell, F.K.

    2000-01-01

    The dissolution of pyrite is important in the geochemical cycling of iron and sulphur, in the formation of acid mine drainage, and in the extraction of metals by bacterial leaching. Many researchers have studied the kinetics of dissolution, and the rate of dissolution has often been found to be half-order in ferric ions or oxygen. Previous work has not adequately explained the kinetics of dissolution of pyrite. The dissolution of pyrite is an oxidation-reduction reaction. The kinetics of the oxidation and reduction half-reactions was studied independently using electrochemical techniques of voltammetry. The kinetics of the overall reaction was studied by the electrochemical technique of potentiometry, which consisted of measuring the mixed potential of a sample of corroding pyrite in solutions of different compositions. The kinetics of the half reactions are related to the kinetics of the overall dissolution reaction by the condition that there is no accumulation of charge. This principle is used to derive expressions for the mixed potential and the rate of dissolution, which successfully describe the mixed potential measurements and the kinetics of dissolution reported in the literature. It is shown that the observations of half-order kinetics and that the oxygen in the sulphate product arises from water are both a direct consequence of the electrochemical mechanism. Thus it is concluded that the electrochemical reaction steps occurring at the mineral-solution interface control the rate of dissolution. Raman spectroscopy was used to analyze reaction products formed on the pyrite surface. The results indicated that small amounts of polysulphides form on the surface of the pyrite. However, it was also found that the mixed (corrosion) potential does not change over a 14-day leaching period. This indicates that even though polysulphide material is present on the surface, it does not influence the rate of the reactions occurring at the surface. Measurement of the sulphur yields as a function of electrode potential indicate that thiosulphate is not the only source of the sulphur product.

  9. Evidence of Nitrogen Loss from Anaerobic Ammonium Oxidation Coupled with Ferric Iron Reduction in an Intertidal Wetland.

    PubMed

    Li, Xiaofei; Hou, Lijun; Liu, Min; Zheng, Yanling; Yin, Guoyu; Lin, Xianbiao; Cheng, Lv; Li, Ye; Hu, Xiaoting

    2015-10-01

    Anaerobic ammonium oxidation coupled with nitrite reduction is an important microbial pathway of nitrogen removal in intertidal wetlands. However, little is known about the role of anaerobic ammonium oxidation coupled with ferric iron reduction (termed Feammox) in intertidal nitrogen cycling. In this study, sediment slurry incubation experiments were combined with an isotope-tracing technique to examine the dynamics of Feammox and its association with tidal fluctuations in the intertidal wetland of the Yangtze Estuary. Feammox was detected in the intertidal wetland sediments, with potential rates of 0.24-0.36 mg N kg(-1) d(-1). The Feammox rates in the sediments were generally higher during spring tides than during neap tides. The tidal fluctuations affected the growth of iron-reducing bacteria and reduction of ferric iron, which mediated Feammox activity and the associated nitrogen loss from intertidal wetlands to the atmosphere. An estimated loss of 11.5-18 t N km(-2) year(-1) was linked to Feammox, accounting for approximately 3.1-4.9% of the total external inorganic nitrogen transported into the Yangtze Estuary wetland each year. Overall, the co-occurrence of ferric iron reduction and ammonium oxidation suggests that Feammox can act as an ammonium removal mechanism in intertidal wetlands. PMID:26360245

  10. EXAFS Analyses of Innersphere Surface Complexations of Arsenate and Silicate on Natural Hydrous Ferric Oxides

    NASA Astrophysics Data System (ADS)

    Tommaseo, C. E.; Kersten, M.

    2002-12-01

    X-ray absorption spectroscopy (EXAFS) was used to determine the near range order of three elements (Fe, As, Si) on the surface of hydrous ferric oxide (HFO) from thermal water scales. Fe K-edge EXAFS analyses of the 2nd shell show a better fit including Si as backscattering neighbor. Validation of the Si-Fe bond was obtained by Si K-edge EXAFS spectra, where the light absorber element is surrounded favourably by much heavier second-shell elements. Least-squares fitting of the second-shell Fourier-filtered EXAFS spectrum in the k-range of 5-11 -1 yields in a Si-Fe distance of 3.10-3.13, and a Si-Si distance of 3.00. Both these interatomic distances and the coordination number N = 2 obtained for the Si-Fe shell are consistent with the formation of a corner-bridging bidentate binuclear (2C) surface complex on the HFO surface. The Si-Si bonds and existance of a vibrational band at 964 cm-1 in the infrared spectrum indicate polymerisation of the silicate on the HFO surface (Tommaseo and Kersten). As K-edge XANES analyses showed the As present in form of arsenate scavenged by the HFO phase. As and Si K-edge EXAFS analyses revealed both elements to compete for 2C surface complexation sites. A mean As-Fe distance of 3.03 indicate an approx. equal distribution of arsenate between 2C (3.24) and another 1E (bidentate mononuclear surface complexation) sites (2.84). The average Fe-(O,OH) bond length of 2.09 is compatible with a high proportion of distorted surficial FeIII(O,OH)6 octahedra in the colloidal HFO precipitates of the scale deposits. The slight distortion of the FeIII(O,OH)6 octahedra is consistent with the apparent strong binding of the 1E arsenate surface complexes (Manceau, 1995). The adverse effect of silicate would therefore be overpredicted without surface complexation models constructed to account for both surface functional groups. The Si K-edge EXAFS data provide also a basis for explaining at the molecular level the poisoning of HFO particle growth and the slowing down of the transformation of HFO to crystalline goethite. The inhibition of crystal growth by both oxoanions form a kind of passivation layer which protects HFO from recrystallization and concomitant release of part of the arsenic upon otherwise rapid ageing in the thermal waters. LITERATURE Manceau, A., The mechanism of anion adsorption on iron oxides: Evidence for the bonding of arsenate tetrahedral on free Fe(O,OH)6 edges. Geochim. Cosmochim Acta, Vol. 59, No 17, 3647-3653 (1995). Tommaseo, C.E. and Kersten, M., EXAFS analysis of competitive adsorption of arsenate and silicate on natural hydrous ferric oxides in thermal water scales. Environ. Sci. Technol. (submitted).

  11. Synthesis of waste cooking oil based biodiesel via ferric-manganese promoted molybdenum oxide / zirconia nanoparticle solid acid catalyst: influence of ferric and manganese dopants.

    PubMed

    Alhassan, Fatah H; Rashid, Umer; Taufiq-Yap, Yun Hin

    2015-01-01

    The utilization of ferric-manganese promoted molybdenum oxide/zirconia (Fe-Mn- MoO3/ZrO2) (FMMZ) solid acid catalyst for production of biodiesel was demonstrated. FMMZ is produced through impregnation reaction followed by calcination at 600C for 3 h. The characterization of FMMZ had been done using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), thermal gravimetric analysis (TGA), temperature programmed desorption of NH3 (TPD-NH3), transmission electron microscopy(TEM) and Brunner-Emmett-Teller (BET) surface area measurement. The effect of waste cooking oil methyl esters (WCOME's) yield on the reactions variables such as reaction temperature, catalyst loading, molar ratio of methanol/oil and reusability were also assessed. The catalyst was used to convert the waste cooking oil into corresponding methyl esters (95.6%0.15) within 5 h at 200? reaction temperature, 600 rpm stirring speed, 1:25 molar ratio of oil to alcohol and 4% w/w catalyst loading. The reported catalyst was successfully recycled in six connective experiments without loss in activity. Moreover, the fuel properties of WCOME's were also reported using ASTM D 6751 methods. PMID:25843280

  12. High k nanophase zinc oxide on biomimetic silicon nanotip array as supercapacitors.

    PubMed

    Han, Hsieh-Cheng; Chong, Cheong-Wei; Wang, Sheng-Bo; Heh, Dawei; Tseng, Chi-Ang; Huang, Yi-Fan; Chattopadhyay, Surojit; Chen, Kuei-Hsien; Lin, Chi-Feng; Lee, Jiun-Haw; Chen, Li-Chyong

    2013-04-10

    A 3D trenched-structure metal-insulator-metal (MIM) nanocapacitor array with an ultrahigh equivalent planar capacitance (EPC) of ~300 ?F cm(-2) is demonstrated. Zinc oxide (ZnO) and aluminum oxide (Al2O3) bilayer dielectric is deposited on 1 ?m high biomimetic silicon nanotip (SiNT) substrate using the atomic layer deposition method. The large EPC is achieved by utilizing the large surface area of the densely packed SiNT (!5 10(10) cm(-2)) coated conformally with an ultrahigh dielectric constant of ZnO. The EPC value is 30 times higher than those previously reported in metal-insulator-metal or metal-insulator-semiconductor nanocapacitors using similar porosity dimensions of the support materials. PMID:23432577

  13. Rare earth element partitioning between hydrous ferric oxides and acid mine water during iron oxidation

    USGS Publications Warehouse

    Verplanck, P.L.; Nordstrom, D.K.; Taylor, H.E.; Kimball, B.A.

    2004-01-01

    Ferrous iron rapidly oxidizes to Fe (III) and precipitates as hydrous Fe (III) oxides in acid mine waters. This study examines the effect of Fe precipitation on the rare earth element (REE) geochemistry of acid mine waters to determine the pH range over which REEs behave conservatively and the range over which attenuation and fractionation occur. Two field studies were designed to investigate REE attenuation during Fe oxidation in acidic, alpine surface waters. To complement these field studies, a suite of six acid mine waters with a pH range from 1.6 to 6.1 were collected and allowed to oxidize in the laboratory at ambient conditions to determine the partitioning of REEs during Fe oxidation and precipitation. Results from field experiments document that even with substantial Fe oxidation, the REEs remain dissolved in acid, sulfate waters with pH below 5.1. Between pH 5.1 and 6.6 the REEs partitioned to the solid phases in the water column, and heavy REEs were preferentially removed compared to light REEs. Laboratory experiments corroborated field data with the most solid-phase partitioning occurring in the waters with the highest pH. ?? 2004 Elsevier Ltd. All rights reserved.

  14. Biogenic iron mineralization accompanying the dissimilatory reduction of hydrous ferric oxide by a groundwater bacterium

    NASA Astrophysics Data System (ADS)

    Fredrickson, James K.; Zachara, John M.; Kennedy, David W.; Dong, Hailang; Onstott, Tullis C.; Hinman, Nancy W.; Li, Shu-mei

    1998-10-01

    Dissimilatory iron-reducing bacteria (DIRB) couple the oxidation of organic matter or H 2 to the reduction of iron oxides. The factors controlling the rate and extent of these reduction reactions and the resulting solid phases are complex and poorly understood. Batch experiments were conducted with amorphous hydrous ferric oxide (HFO) and the DIRB Shewanella putrefaciens, strain CN32, in well-defined aqueous solutions to investigate the reduction of HFO and formation of biogenic Fe(II) minerals. Lactate-HFO solutions buffered with either bicarbonate or 1,4-piperazinediethanesulfonic acid (PIPES) containing various combinations of phosphate and anthraquinone-2,6-disulfonate (AQDS), were inoculated with S. putrefaciens CN32. AQDS, a humic acid analog that can be reduced to dihydroanthraquinone by CN32, was included because of its ability to function as an electron shuttle during microbial iron reduction and as an indicator of pe. Iron reduction was measured with time, and the resulting solids were analyzed by X-ray diffraction, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) with energy-dispersive X-ray spectroscopy (EDS) and selected area electron diffraction (SAED). In HCO 3- buffered medium with AQDS, HFO was rapidly and extensively reduced, and the resulting solids were dominated by ferrous carbonate (siderite). Ferrous phosphate (vivianite) was also present in HCO 3- medium containing P, and fine-grained magnetite was present as a minor phase in HCO 3- medium with or without P. In the PIPES-buffered medium, the rate and extent of reduction was strongly influenced by AQDS and P. With AQDS, HFO was rapidly converted to highly crystalline magnetite whereas in its absence, magnetite mineralization was slower and the final material less crystalline. In PIPES with both P and AQDS, a green rust type compound [Fe (6-x)IIFe xIII(OH) 12] x+[(A 2-) x/2 yH 2O] x- was the dominant solid phase formed; in the absence of AQDS a poorly crystalline product was observed. The measured pe and nature of the solids identified were consistent with thermodynamic considerations. The composition of aqueous media in which microbial iron reduction occurred strongly impacted the rate and extent of iron reduction and the nature of the reduced solids. This, in turn, can provide a feedback control mechanism on microbial metabolism. Hence, in sediments where geochemical conditions promote magnetite formation, two-thirds of the Fe(III) will be sequestered in a form that may not be available for anaerobic bacterial respiration.

  15. Moessbauer spectroscopic investigations of nanophase iron oxides synthesized by thermal plasma route

    SciTech Connect

    Harshada Nagar; Kulkarni, Naveen V.; Karmakar, Soumen; Sahoo, B.; Banerjee, I.; Chaudhari, P.S.; Pasricha, R.; Das, A.K.; Bhoraskar, S.V. Date, S.K.; Keune, W.

    2008-09-15

    Magnetic nanoparticles of iron oxide were synthesized by transferred arc plasma induced gas phase condensation method. Structural, morphological and magnetic studies of the as synthesized powder were carried out using X-ray diffraction, transmission electron microscopy and Moessbauer spectroscopy. These studies have revealed the simultaneous nucleation and condensation of different magnetic phases with a broad size distribution of the nanoparticles which is peaked at 30-50 nm and ranges from 10 nm to 80 nm. {sup 57}Fe Moessbauer spectra recorded at various temperatures (5 K-300 K) in presence of external magnetic field (at 5 K) have suggested the presence of different phases of iron oxide with sizable amounts of {gamma}-Fe{sub 2}O{sub 3} and {alpha}-Fe{sub 2}O{sub 3} in addition to Fe{sub 3}O{sub 4}. The relative concentrations of these phases have been obtained by a self consistent spectral area analysis and were found to be 44:22:34 (%)

  16. Removal of arsenate with hydrous ferric oxide coprecipitation: effect of humic acid.

    PubMed

    Du, Jingjing; Jing, Chuanyong; Duan, Jinming; Zhang, Yongli; Hu, Shan

    2014-02-01

    Insights from the adverse effect of humic acid (HA) on arsenate removal with hydrous ferric oxide (HFO) coprecipitation can further our understanding of the fate of As(V) in water treatment process. The motivation of our study is to explore the competitive adsorption mechanisms of humic acid and As(V) on HFO on the molecular scale. Multiple complementary techniques were used including macroscopic adsorption experiments, surface enhanced Raman scattering (SERS), extended X-ray absorption fine structure (EXAFS) spectroscopy, flow-cell attenuated total reflectance Fourier transform infrared (ATR-FTIR) measurement, and charge distribution multisite complexation (CD-MUSIC) modeling. The As(V) removal efficiency was reduced from over 95% to about 10% with the increasing HA concentration to 25 times of As(V) mass concentration. The SERS analysis excluded the HA-As(V) complex formation. The EXAFS results indicate that As(V) formed bidentate binuclear surface complexes in the presence of HA as evidenced by an As-Fe distance of 3.26-3.31 angstroms. The in situ ATR-FTIR measurements show that As(V) replaces surface hydroxyl groups and forms innersphere complex. High concentrations of HA may physically block the surface sites and inhibit the As(V) access. The adsorption of As(V) and HA decreased the point of zero charge of HFO from 7.8 to 5.8 and 6.3, respectively. The CD-MUSIC model described the zeta potential curves and adsorption edges of As(V) and HA reasonably well. PMID:25076514

  17. 21 CFR 184.1297 - Ferric chloride.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ferric chloride. 184.1297 Section 184.1297 Food and... Substances Affirmed as GRAS 184.1297 Ferric chloride. (a) Ferric chloride (iron (III) chloride, FeC13, CAS Reg. No. 7705-08-0) may be prepared from iron and chlorine or from ferric oxide and hydrogen...

  18. 21 CFR 184.1297 - Ferric chloride.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Ferric chloride. 184.1297 Section 184.1297 Food... GRAS 184.1297 Ferric chloride. (a) Ferric chloride (iron (III) chloride, FeC13, CAS Reg. No. 7705-08-0) may be prepared from iron and chlorine or from ferric oxide and hydrogen chloride. The...

  19. Immobilization of strontium during iron biomineralization coupled to dissimilatory hydrous ferric oxide reduction

    NASA Astrophysics Data System (ADS)

    Roden, Eric E.; Leonardo, Michael R.; Ferris, F. Grant

    2002-09-01

    The potential for incorporation of strontium (Sr) into biogenic Fe(II)-bearing minerals formed during microbial reduction of synthetic hydrous ferric oxide (HFO) was investigated in circumneutral bicarbonate-buffered medium containing SrCl 2 at concentrations of 10 ?M, 100 ?M, or 1.0 mM. CaCl 2 (10 mM) was added to some experiments to simulate a Ca-rich groundwater. In Ca-free systems, 89 to 100% of total Sr was captured in solid-phase compounds formed during reduction of 30 to 40 mmol Fe(III) L -1 over a 1-month period. A smaller fraction of total Sr (25 to 34%) was incorporated into the solid phase in cultures amended with 10 mM CaCl 2. X-ray diffraction identified siderite and ferroan ankerite as major end products of HFO reduction in Ca-free and Ca-amended cultures, respectively. Scanning electron microscopy-energy dispersive x-ray spectroscopy revealed the presence of Sr associated with carbonate phases. Selective extraction of HFO reduction end products indicated that 46 to 100% of the solid-phase Sr was associated with carbonates. The sequestration of Sr into carbonate phases in the Ca-free systems occurred systematically according to a heterogeneous (Doerner-Hoskins) partition coefficient (D D-H) of 1.81 0.15. This D D-H value was 2 to 10 times higher than values determined for incorporation of Sr (10 ?M) into FeCO 3(s) precipitated abiotically at rates comparable to or greater than rates observed during HFO reduction, and fivefold higher than theoretical partition coefficients for equilibrium Fe(Sr)CO 3 solid solution formation. Surface complexation and entrapment of Sr by rapidly growing siderite crystals (and possibly other biogenic Fe(II) solids) provides an explanation for the intensive scavenging of Sr in the Ca-free systems. The results of abiotic siderite precipitation experiments in the presence and absence of excess Ca indicate that substitution of Ca for Sr at foreign element incorporation sites (mass action effect) on growing FeCO 3(s) surfaces can account for the inhibition of Sr incorporation into the siderite component of ankerite formed in the Ca-amended HFO reduction experiments. Likewise, substitution of Fe(II) for Sr may explain the absence of major Sr partitioning into the calcite component of ankerite. The findings indicate that under appropriate conditions, sequestration of metals in siderite produced during bacterial Fe(III) oxide reduction may provide a mechanism for retarding the migration of Sr and other divalent metal contaminants in anaerobic, carbonate-rich sedimentary environments.

  20. Enhancement of Fenton oxidation for removing organic matter from hypersaline solution by accelerating ferric system with hydroxylamine hydrochloride and benzoquinone.

    PubMed

    Peng, Siwei; Zhang, Weijun; He, Jie; Yang, Xiaofang; Wang, Dongsheng; Zeng, Guisheng

    2016-03-01

    Fenton oxidation is generally inhibited in the presence of a high concentration of chloride ions. This study investigated the feasibility of using benzoquinone (BQ) and hydroxylamine hydrochloride (HA) as Fenton enhancers for the removal of glycerin from saline water under ambient temperature by accelerating the ferric system. It was found that organics removal was not obviously affected by chloride ions of low concentration (less than 0.1mol/L), while the mineralization rate was strongly inhibited in the presence of a large amount of chloride ions. In addition, ferric hydrolysis-precipitation was significantly alleviated in the presence of HA and BQ, and HA was more effective in reducing ferric ions into ferrous ions than HA, while the H2O2 decomposition rate was higher in the BQ-Fenton system. Electron spin resonance analysis revealed that OH production was reduced in high salinity conditions, while it was enhanced after the addition of HA and BQ (especially HA). This study provided a possible solution to control and alleviate the inhibitory effect of chloride ions on the Fenton process for organics removal. PMID:26969046

  1. Mafic Silicate and Ferric Oxide Mineralogy of Gale Crater and the Mars Science Laboratory Rover Field Site

    NASA Astrophysics Data System (ADS)

    Bell, J. F.; Anderson, R. B.; Milliken, R.; Hamilton, V. E.; Edgett, K. S.

    2011-12-01

    Gale, a 155 km diameter impact crater on the boundary of the Martian southern highlands near 5S, 222W, has been selected as the field site for NASA's Mars Science Laboratory (MSL) rover, Curiosity. Several published studies have focused on the discovery, mapping, and analysis of hydrated or hydroxylated minerals (e.g., sulfates, phyllosilicates) in Gale as exciting potential targets for in situ exploration. Less attention has generally been paid to the anhydrous mafic (ferrous) silicates and ferric oxides which have also been detected in Gale from orbital remote sensing studies and which may be the precursor parent materials that weathered into the observed aqueous phases. Here we review previous and new observations regarding the presence and spatial distribution of anhydrous ferrous silicates and ferric oxides in Gale and discuss the scientific implications for the close-up study of these materials with the MSL payload. Despite a common misconception that Gale is a "dusty" site, visible to near-IR observations from the Mars Express OMEGA and Mars Reconnaissance Orbiter CRISM and thermal infrared observations from Mars Global Surveyor TES and Mars Odyssey THEMIS provide evidence for olivine and pyroxene and the anhydrous ferric oxide, hematite, associated with distinct geologic materials in Gale. Olivine-bearing mafic (likely basaltic) materials have been interpreted to occur in low albedo aeolian dunes near and around the base of the 5 km high mound of sedimentary rock in the crater. Both low and high calcium pyroxene (LCP, HCP) have been identified in and around the crater, with CRISM data showing HCP-bearing material occurring primarily within a "cap rock" on the relatively flat crater floor and within the relatively dust-free units of the lower few km of the sedimentary rock mound. Potentially more mobile (via wind) LCP-bearing material occurs throughout the crater and the lower few km of the mound and into the low albedo wind streak that extends ~200 km to the south. Models of TES spectral data are consistent with the presence of LCP+HCP, high silica phases, feldspar, olivine, and possibly sulfate in the low albedo surfaces exposed in the crater, central mound, and southern wind streak. VNIR data reveal that a ferric oxide phase, potentially fine-grained (red) hematite, occurs in association with both HCP and LCP units in a so-called "mound skirting unit" within the Curiosity field site. THEMIS and CRISM imaging both display compositional layering within mound materials that will be accessible to the rover.

  2. Optical Study of Cuprous Oxide and Ferric Oxide Based Materials for Applications in Low Cost Solar Cells

    NASA Astrophysics Data System (ADS)

    Than, Thi Cuc; Bui, Bao Thoa; Wegmuller, Benjamin; Nguyen, Minh Hieu; Hoang Ngoc, Lam Huong; Bui, Van Diep; Nguyen, Quoc Hung; Hoang, Chi Hieu; Nguyen-Tran, Thuat

    2016-02-01

    One of the interesting forms of cuprous oxide and ferric oxide based materials is CuFeO2 which can be a delafossite-type compound and is a well known p-type semiconductor. This compound makes up an interesting family of materials for technological applications. CuFeO2 thin films recently gained renewed interest for potential applications in solar cell devices especially as absorption layers. One of the interesting facts is that CuFeO2 is made from cheap materials such as copper and iron. In this study, CuFeO2 thin films are intentionally deposited on corning glass and silicon substrates by the radio-frequency and direct current sputtering method with complicated and well developed co-sputtering recipes. The deposition was performed at room temperature which leads to an amorphous phase with extremely low roughness and high density. The films also were annealed at 500°C in 5% H2 in Ar for the passivation. A detailed optical study was performed on these thin films by spectroscopic ellipsometry and by ultra-violet visible near infrared spectroscopy. Depending on sputtering conditions, the direct band gap was extrapolated to be from 1.96 eV to 2.2 eV and 2.92 eV to 2.96 eV and the indirect band gap is about 1.22 eV to 1.42 eV. A good electrical conduction is also observed which is suitable for solar cell applications. In future more study on the structural properties will be carried out in order to fully understand these materials.

  3. 21 CFR 73.1298 - Ferric ammonium ferrocyanide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...) Identity. (1) The color additive ferric ammonium ferrocyanide is the blue pigment obtained by oxidizing... product is filtered, washed, and dried. The pigment consists principally of ferric ammonium...

  4. 21 CFR 73.1298 - Ferric ammonium ferrocyanide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...) Identity. (1) The color additive ferric ammonium ferrocyanide is the blue pigment obtained by oxidizing... product is filtered, washed, and dried. The pigment consists principally of ferric ammonium...

  5. 21 CFR 73.1298 - Ferric ammonium ferrocyanide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...) Identity. (1) The color additive ferric ammonium ferrocyanide is the blue pigment obtained by oxidizing... product is filtered, washed, and dried. The pigment consists principally of ferric ammonium...

  6. 21 CFR 73.1298 - Ferric ammonium ferrocyanide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...) Identity. (1) The color additive ferric ammonium ferrocyanide is the blue pigment obtained by oxidizing... product is filtered, washed, and dried. The pigment consists principally of ferric ammonium...

  7. 21 CFR 184.1307 - Ferric sulfate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Ferric sulfate. 184.1307 Section 184.1307 Food and....1307 Ferric sulfate. (a) Ferric sulfate (iron (III) sulfate, Fe2(SO4)3 CAS Reg. No. 10028-22-5) is a yellow substance that may be prepared by oxidizing iron (II) sulfate or by treating ferric oxide...

  8. The Induction of Oxidative/Nitrosative Stress, Inflammation, and Apoptosis by a Ferric Carboxymaltose Copy Compared to Iron Sucrose in a Non-Clinical Model

    PubMed Central

    Cao, Gabriel; Angerosa, Margarita

    2015-01-01

    Introduction Ferric carboxymaltose is a next-generation polynuclear iron(III)-hydroxide carbohydrate complex for intravenous iron therapy belonging to the class of so-called non-biological complex drugs. The product characteristics and therapeutic performance of non-biological complex drugs are largely defined by the manufacturing process. A follow-on product, termed herein as ferric carboxymaltose similar, is available in India. Given that non-biological complex drugs may display differences in diverse product properties not characterisable by physico-chemical methods alone. Aim The aim is to assess the effects of this ferric carboxymaltose similar in our non-clinical model in non-anaemic healthy rats. Materials and Methods Non-anaemic rats were treated with intravenous ferric carboxymaltose similar or iron sucrose both at (40 mg iron/kg body weight), or with saline solution (control) for four weeks, after which the animals were sacrificed. Parameters for tissue iron distribution, oxidative stress, nitrosative stress, inflammation and apoptosis were assessed by immunohistomorphometry. Results Ferric carboxymaltose similar resulted in deranged iron distribution versus iron sucrose originator as indicated by increased serum iron, transferrin saturation and tissue iron(III) deposits as well as decreased ferritin deposits in the liver, heart and kidneys versus iron sucrose originator. Ferric carboxymaltose similar also increased significantly oxidative/nitrosative stress, pro-inflammatory, and apoptosis markers in the liver, heart and kidneys versus iron sucrose originator. Conclusion In our rat model, ferric carboxymaltose similar had a less favourable safety profile than iron sucrose originator, adversely affecting iron deposition, oxidative and nitrosative stress, inflammatory responses, with impaired liver and kidney function. PMID:26816915

  9. Fayalite Oxidation Processes: Experimental Evidence for the Stability of Pure Ferric Fayalite?

    NASA Technical Reports Server (NTRS)

    Martin, A. M.; Righter, K.; Keller, L. P.; Medard, E.; Devouard, B.; Rahman, Z.

    2011-01-01

    Olivine is one of the most important minerals in Earth and planetary sciences. Fayalite Fe2(2+)SiO4, the ferrous end-member of olivine, is present in some terrestrial rocks and primitive meteorites (CV3 chondrites). A ferric fayalite (or ferri-fayalite), Fe(2+) Fe2(3+)(SiO4)2 laihunite, has been reported in Earth samples (magnetite ore, metamorphic and volcanic rocks...) and in Martian meteorites (nakhlites). Laihunite was also synthesized at 1 atmosphere between 400 and 700 C. We show evidence for the stability of a pure ferrifayalite end-member and for potential minerals with XFe(3+) between 2/3 and 1.

  10. Visible Wavelength Spectroscopy of Ferric Minerals: A Key Tool for Identification of Ancient Martian Aqueous Environments

    NASA Technical Reports Server (NTRS)

    Murchie, Scott L.; Bell, J. F., III; Morris, Richard V.

    2000-01-01

    The mineralogic signatures of past aqueous alteration of a basaltic Martian crust may include iron oxides and oxyhydroxides, zeolites, carbonates, phyllosilicates, and silica. The identities, relative abundances, and crystallinities of the phases formed in a particular environment depend on physicochemical conditions. At one extreme, hot spring environments may be characterized by smectite-chlorite to talc-kaolinite silicate assemblages, plus crystalline ferric oxides dominated by hematite. However, most environments, including cold springs, pedogenic layers, and ponded surface water, are expected to deposit iron oxides and oxyhydroxides, carbonates, and smectite-dominated phyllosilicates. A substantial fraction of the ferric iron is expected to occur in nanophase form, with the exact mineralogy strongly influenced by Eh-pH conditions. Detection of these phases has been an objective of a large body of terrestrial telescopic, Mars orbital, and landed spectral investigations and in situ compositional measurements. However, clear identifications of many of these phases is lacking. Neither carbonate nor silica has been unequivocally detected by any method. Although phyllosilicates may occur near the limit of detection by remote sensing, in general they appear to occur in only poorly crystalline form. In contrast, compelling evidence for ferric iron minerals has been gathered by recent telescopic investigations, the Imager for Mars Pathfinder (IMP), and the Thermal Emission Spectrometer (TES) on the Mars Global Surveyor (MGS). These data yield two crucial findings: (1) In the global, high spatial resolution TES data set, highly crystalline ferric iron (as coarse-grained 'gray' hematite) has been recognized but with only very limited spatial occurrence and (2) Low-resolution telescopic reflectance spectroscopy, very limited orbital reflectance spectroscopy, and landed multispectral imaging provide strong indications that at least two broad classes of ferric iron minerals are commonplace in non-dust covered regions.

  11. Syzyguim guineense Extracts Show Antioxidant Activities and Beneficial Activities on Oxidative Stress Induced by Ferric Chloride in the Liver Homogenate

    PubMed Central

    Pieme, Constant Anatole; Ngoupayo, Joseph; Khou-Kouz Nkoulou, Claude Herve; Moukette Moukette, Bruno; Njinkio Nono, Borgia Legrand; Ama Moor, Vicky Jocelyne; Ze Minkande, Jacqueline; Yonkeu Ngogang, Jeanne

    2014-01-01

    The aim of this study was to determine the in vitro antioxidant activity, free radical scavenging property and the beneficial effects of extracts of various parts of Syzygium guineense in reducing oxidative stress damage in the liver. The effects of extracts on free radicals were determined on radicals DPPH, ABTS, NO and OH followed by the antioxidant properties using Ferric Reducing Antioxidant Power assay (FRAP) and hosphomolybdenum (PPMB). The phytochemical screening of these extracts was performed by determination of the phenolic content. The oxidative damage inhibition in the liver was determined by measuring malondialdehyde (MDA) as well as the activity of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) and peroxidase. Overall, the bark extract of the ethanol/water or methanol showed the highest radical scavenging activities against DPPH, ABTS and OH radicals compared to the other extracts. This extract also contained the highest phenolic content implying the potential contribution of phenolic compounds towards the antioxidant activities. However, the methanol extract of the root demonstrated the highest protective effects of SOD and CAT against ferric chloride while the hydro-ethanol extract of the leaves exhibited the highest inhibitory effects on lipid peroxidation. These findings suggest that antioxidant properties of S. guineense extracts could be attributed to phenolic compounds revealed by phytochemical studies. Thus, the present results indicate clearly that the extracts of S. guineense possess antioxidant properties and could serve as free radical inhibitors or scavengers, acting possibly as primary antioxidants. The antioxidant properties of the bark extract may thus sustain its various biological activities. PMID:26785075

  12. Ferric Oxide Mediated Formation of PCDD/Fs from 2-Monochlorophenol

    PubMed Central

    Nganai, Shadrack; Lomnicki, Slawo; Dellinger, Barry

    2012-01-01

    The copper oxide, surface-mediated formation of polychlorinated dibenzop-dioxins and dibenzofurans (PCDD/F) from precursors such as chlorinated phenols is considered to be a major source of PCDD/F emissions from combustion sources. In spite of being present at 2–50x higher concentrations than copper oxide, virtually no studies of the iron oxide-mediated formation of PCDD/F have been reported in the literature. We have performed packed bed, flow reactor studies of the reaction of 50 ppm gas phase 2-monochlorophenol (2-MCP) over a surface of 5% iron oxide on silica over a temperature range of 200–500 °C. Dibenzo-p-dioxin (DD), 1-monochlorodibenzo-p-dioxin (1-MCDD), 4,6-dichlorodibenzofuran (4,6-DCDF), and dibenzofuran (DF) were formed in maximum yields of 0.1, 0.2, 0.3, and 0.4 %, respectively. The yield of PCDD/F over iron oxide peaked at temperatures 50–100 °C higher in temperature than over copper oxide. The maximum yields of DD, 1-MCDD and 4,6-DCDF were 2x and 5x higher over iron oxide, respectively, than over copper oxide, while DF was not observed at all for copper oxide. The resulting PCDD/PCDF ratio was 0.39 versus 1.2 observed for iron oxide and copper oxide, respectively, which is in agreement with PCDD to PCDF ratios in full-scale combustors that are typically ≪1. The combination of 2–50x higher concentrations of iron oxide than copper oxide in most full-scale combustors and 2.5x higher yields of PCDD/F observed in the laboratory, suggest that iron oxide may contribute as much as 5–125x more than copper oxide to the emissions of PCDD/F from full-scale combustors. PMID:19238966

  13. Biodiesel synthesis catalyzed by transition metal oxides: ferric-manganese doped tungstated/molybdena nanoparticle catalyst.

    PubMed

    Alhassan, Fatah Hamid; Rashid, Umer; Taufiq-Yap, Yun Hin

    2015-01-01

    The solid acid Ferric-manganese doped tungstated/molybdena nananoparticle catalyst was prepared via impregnation reaction followed by calcination at 600C for 3 h. The characterization was done using X-ray diffraction (XRD), Raman spectroscopy, thermal gravimetric analysis (TGA), temperature programmed desorption of NH3 (TPD-NH3), X-ray fluorescence (XRF), Transmission electron microscope (TEM) and Brunner-Emmett-Teller surface area measurement (BET). Moreover, dependence of biodiesel yield on the reaction variables such as the reaction temperature, catalyst loading, as well as molar ratio of methanol/oil and reusability were also appraised. The catalyst was reused six times without any loss in activity with maximum yield of 92.3% 1.12 achieved in the optimized conditions of reaction temperature of 200C; stirring speed of 600 rpm, 1:25 molar ratio of oil to alcohol, 6 % w/w catalyst loading as well as 8 h as time of the reaction. The fuel properties of WCOME's were evaluated, including the density, kinematic viscosity, pour point, cloud point and flash point whereas all properties were compared with the limits in the ASTM D6751 standard. PMID:25492234

  14. Amperometric determination of acetylcholine-A neurotransmitter, by chitosan/gold-coated ferric oxide nanoparticles modified gold electrode.

    PubMed

    Chauhan, Nidhi; Pundir, C S

    2014-11-15

    An amperometric acetylcholine biosensor was constructed by co-immobilizing covalently, a mixture of acetylcholinesterase (AChE) and choline oxidase (ChO) onto nanocomposite of chitosan (CHIT)/gold-coated ferric oxide nanoparticles (Fe@AuNPs) electrodeposited onto surface of a Au electrode and using it as a working electrode, Ag/AgCl as reference electrode and Pt wire as auxiliary electrode connected through potentiostat. The biosensor is based on electrochemical measurement of H2O2 generated from oxidation of choline by immobilized ChO, which in turn is produced from hydrolysis of acetylcholine by immobilized AChE. The biosensor exhibited optimum response within 3s at +0.2V, pH 7.0 and 30°C. The enzyme electrode had a linear working range of 0.005-400 µM, with a detection limit of 0.005 µM for acetylcholine. The biosensor measured plasma acetylcholine in apparently healthy and persons suffering from Alzheimer's disease. The enzyme electrode was unaffected by a number of serum substances but lost 50% of its initial activity after its 100 uses over a period of 3 months, when stored at 4°C. PMID:24836212

  15. Ameliorative effect of polyphenols from Padina boergesenii against ferric nitrilotriacetate induced renal oxidative damage: With inhibition of oxidative hemolysis and in vitro free radicals.

    PubMed

    Rajamani, Karthikeyan; Renju, V C; Sethupathy, S; Thirugnanasambandan, Somasundaram S

    2015-07-01

    The aim of this study was to evaluate the antioxidant activities of diethyl ether (DEE) and methanol (M) extracts from brown alga Padina boergesenii using in vitro and in vivo antioxidant assay, which may help to relate the antioxidant properties with the possible outline of its ameliorative effect. M extract showed higher radical scavenging activity through ferric reducing antioxidant power 139.11 mol tannic acid equivalent/g; DPPH 71.32??0.56%; deoxyribose radical 88.31??0.47%, and total antioxidant activity 0.47??0.02 mg ascorbic acid equivalents/g. Oxidative red blood cell (RBC) hemolysis inhibition rate was significantly higher in M extract (150 mg/kg body weight) in reference to total phenolic content (r = 0.935). Rats administered with DEE and M extracts (150 mg/kg body weight) for seven days before the administration of ferric nitrilotriacetate (9 mg of Fe/mg/kg bodyweight). Rats pretreated with extracts significantly changed the level of renal microsomal lipid peroxidation, glutathione, and antioxidant enzymes in post-mitochondrial supernatant (P?oxidative damage was evident in rat kidney through changes in necrotic and epithelial cells. HPTLC technique has identified the presence of rutin with reference to retardation factor (Rf ) in both the extracts. These findings support the source of polyphenols (rutin) from P. boergesenii had potent antioxidant activity; further work on isolation of bioactive compounds can be channeled to develop as a natural antioxidant. PMID:24458998

  16. Detecting Adsorbed Sulfate and Phosphate on Nanophase Weathering Products on Mars

    NASA Astrophysics Data System (ADS)

    Rampe, E. B.; Morris, R. V.

    2012-12-01

    Characterizing the mineralogy and chemistry of aqueous alteration phases on the martian surface is essential for understanding past aqueous processes because the types of secondary phases present and their chemical compositions tell us about the environments in which they formed. Orbital mid-infrared data and in-situ mineralogical and chemical data from the martian surface indicate that Si/Al- and Fe-bearing nanophase weathering products are widespread, including allophane and nanophase ferric oxide (npOx), which includes any combination of superparamagnetic hematite and goethite, ferrihydrite, schwertmannite, akaganeite, iddingsite, and palagonite (altered basaltic glass) [Morris et al., 2006; Michalski et al., 2006; Rampe et al., in press]. These weathering products have larger surface areas and variable surface charge and can adsorb anions and cations onto their surfaces. Some anions, such as sulfate and phosphate, specifically chemically adsorb onto mineral/mineraloid surfaces so that these complexes are covalently bonded and form ligands. Nanophase weathering products on Earth can specifically adsorb up to a few weight percent to a few tens of weight percent phosphate and sulfate, respectively [Parfitt and Smart, 1978; Jara et al., 2006]. Phosphate and sulfate have been identified in martian rocks and soils in abundances of up to ~5 wt.% and ~30 wt.%, respectively [Gellert et al., 2006; Ming et al., 2006], and it has been suggested that phosphate and sulfate ions may be adsorbed on nanophase weathering products on the martian surface [Greenwood and Blake, 2006; Morris et al., 2006]. What is relatively unknown is how to use in-situ and orbital instruments on Mars to determine if these ions are present as discrete minerals or adsorbed onto the surfaces of weathering products. We adsorbed phosphate and sulfate onto allophane surfaces in the laboratory. Here, we present laboratory measurements of phosphate- and sulfate-adsorbed allophane to compare to in-situ observations from CheMin and SAM on Mars Science Laboratory and remote observations from OMEGA, CRISM, and TES. CheMin- and OMEGA/CRISM-relevant laboratory measurements reveal minor differences between ion-free and ion-adsorbed allophane that would not be detectable by those instruments. However, SAM-relevant evolved gas analyses of sulfate-adsorbed allophane show a high-temperature (>950 C) release related to SO2 gas. The release at high temperatures suggests that sulfate was strongly bonded to the allophane surface. TES-relevant thermal-infrared emission spectra of phosphate- and sulfate-adsorbed allophane display broad absorptions near 1000 cm-1 from P-O and S-O vibrations. Our laboratory measurements suggest that ions adsorbed onto weathering product surfaces may be recognized on Mars with in-situ measurements by SAM on MSL and with orbital measurements from TES. Future experiments will include similar laboratory measurements of phosphate- and sulfate-adsorbed nanophase ferric oxides.

  17. Nitrogen Requirement of Iron-Oxidizing Thiobacilli for Acidic Ferric Sulfate Regeneration

    PubMed Central

    Tuovinen, Olli H.; Panda, Fern A.; Tsuchiya, Henry M.

    1979-01-01

    Ammonium was shown to be a limiting nutrient for iron oxidation in cultures of Thiobacillus ferrooxidans. In addition, one strain was also able to assimilate nitrate, but not nitrite, for growth and coupled iron oxidation. Some amino acids (0.5 mM) were tested as a source of nitrogen; none clearly stimulated bacterial activity and inhibition was commonly encountered. Complex nitrogenous compounds were inhibitory at high concentrations (0.1 to 0.5%, wt/vol) and, at low concentrations, some clearly stimulated the bacterial iron oxidation in ammonium-limited cultures. Enhancement of iron oxidation by these compounds was also observed in ammonium-unlimited cultures, suggesting their possible role in providing trace nutrients and possibly carbon for the bacteria. PMID:16345391

  18. Experimental constraints on Fe isotope fractionation during magnetite and Fe carbonate formation coupled to dissimilatory hydrous ferric oxide reduction

    NASA Astrophysics Data System (ADS)

    Johnson, Clark M.; Roden, Eric E.; Welch, Susan A.; Beard, Brian L.

    2005-02-01

    Iron isotope fractionation between aqueous Fe(II) and biogenic magnetite and Fe carbonates produced during reduction of hydrous ferric oxide (HFO) by Shewanella putrefaciens, Shewanella algae, and Geobacter sulfurreducens in laboratory experiments is a function of Fe(III) reduction rates and pathways by which biogenic minerals are formed. High Fe(III) reduction rates produced 56Fe/ 54Fe ratios for Fe(II) aq that are 2-3 lower than the HFO substrate, reflecting a kinetic isotope fractionation that was associated with rapid sorption of Fe(II) to HFO. In long-term experiments at low Fe(III) reduction rates, the Fe(II) aq-magnetite fractionation is -1.3, and this is interpreted to be the equilibrium fractionation factor at 22C in the biologic reduction systems studied here. In experiments where Fe carbonate was the major ferrous product of HFO reduction, the estimated equilibrium Fe(II) aq-Fe carbonate fractionations were ca. 0.0 for siderite (FeCO 3) and ca. +0.9 for Ca-substituted siderite (Ca 0.15Fe 0.85CO 3) at 22C. Formation of precursor phases such as amorphous nonmagnetic, noncarbonate Fe(II) solids are important in the pathways to formation of biogenic magnetite or siderite, particularly at high Fe(III) reduction rates, and these solids may have 56Fe/ 54Fe ratios that are up to 1 lower than Fe(II) aq. Under low Fe(III) reduction rates, where equilibrium is likely to be attained, it appears that both sorbed Fe(II) and amorphous Fe(II)(s) components have isotopic compositions that are similar to those of Fe(II) aq. The relative order of ? 56Fe values for these biogenic minerals and aqueous Fe(II) is: magnetite > siderite ? Fe(II) aq > Ca-bearing Fe carbonate, and this is similar to that observed for minerals from natural samples such as Banded Iron Formations (BIFs). Where magnetite from BIFs has ? 56Fe >0, the calculated ? 56Fe value for aqueous Fe(II) suggests a source from midocean ridge (MOR) hydrothermal fluids. In contrast, magnetite from BIFs that has ? 56Fe ?0 apparently requires formation from aqueous Fe(II) that had very low ? 56Fe values. Based on this experimental study, formation of low-? 56Fe Fe(II) aq in nonsulfidic systems seems most likely to have been produced by dissimilatory reduction of ferric oxides by Fe(III)-reducing bacteria.

  19. The Ferric Mineralogy of Mars

    NASA Astrophysics Data System (ADS)

    Bell, James Francis, III

    1992-01-01

    This dissertation presents new telescopic observations of Mars using the technique of imaging spectroscopy. Data at high spectral resolution (lambda/ Deltalambda = 350) and at the best possible spatial resolution (80-150 km) were obtained from Mauna Kea Observatory during the 1988 perihelic opposition. Spectra from 0.4-0.8 ?m reveal distinct absorption features and slope changes that are characteristic of Fe^{3+}-bearing minerals. Poorly crystalline materials, similar to nanophase ferric minerals or palagonite-like weathering products of basaltic glass, dominate the spectral behavior of the Martian surface in the visible to near-IR. Analysis of absorption band shapes and positions and the strong near-UV ferric absorption edge provides solid evidence for the detection of minor amounts (4-8%) of crystalline hematite (alpha -Fe_2O_3) on Mars. Different models for the formation of hematite and other ferric minerals in the current and possibly past warmer, wetter Martian climate are discussed. Images in the 0.4-1.0 ?m region reveal the "classical" albedo features at red and green wavelengths (lambda > 0.5 ?m) and show a spectrally bland surface dominated by polar ices and atmospheric condensates at blue wavelengths. The main results are that (1) the 2-5% deep 0.6-0.7 mu m ferric absorption band varies across the surface with bright regions typically having a deeper band; (2) many dark regions and isolated bright regions are more spectrally heterogeneous than once thought; (3) 95% of the variance in Mars spectra can be modeled using two endmembers (classical bright and dark regions), and spatially coherent units within the remaining variance correlate with condensates and dark, ferric-rich materials; (4) ferric minerals have absorption features at 0.9-1.0 mum, and weak bands observed in previous Mars spectra at these wavelengths that have been ascribed entirely to Fe ^{2+} minerals may also be consistent with variations in Fe^{3+} mineralogy. The advantages of imaging spectroscopy over other observing techniques make it an ideal tool for high spatial resolution spacecraft studies of the Martian surface.

  20. Mercury (II) reduction and co-precipitation of metallic mercury on hydrous ferric oxide in contaminated groundwater.

    PubMed

    Richard, Jan-Helge; Bischoff, Cornelia; Ahrens, Christian G M; Biester, Harald

    2016-01-01

    Mercury (Hg) speciation and sorption analyses in contaminated aquifers are useful for understanding transformation, retention, and mobility of Hg in groundwater. In most aquifers hydrous ferric oxides (HFOs) are among the most important sorbents for trace metals; however, their role in sorption or mobilization of Hg in aquifers has been rarely analyzed. In this study, we investigated Hg chemistry and Hg sorption to HFO under changing redox conditions in a highly HgCl2-contaminated aquifer (up to 870μgL(-1) Hg). Results from aqueous and solid phase Hg measurements were compared to modeled (PHREEQC) data. Speciation analyses of dissolved mercury indicated that Hg(II) forms were reduced to Hg(0) under anoxic conditions, and adsorbed to or co-precipitated with HFO. Solid phase Hg thermo-desorption measurements revealed that between 55 and 93% of Hg bound to HFO was elemental Hg (Hg(0)). Hg concentrations in precipitates reached more than 4 weight %, up to 7000 times higher than predicted by geochemical models that do not consider unspecific sorption to and co-precipitation of elemental Hg with HFO. The observed process of Hg(II) reduction and Hg(0) formation, and its retention and co-precipitation by HFO is thought to be crucial in HgCl2-contaminated aquifers with variable redox-conditions regarding the related decrease in Hg solubility (factor of ~10(6)), and retention of Hg in the aquifer. PMID:26352645

  1. Uranyl adsorption onto hydrous ferric oxide-A re-evaluation for the diffuse layer model database.

    PubMed

    Mahoney, John J; Cadle, Sonya A; Jakubowski, Ryan T

    2009-12-15

    The diffuse layer model (DLM) database of Dzombak and Morel was developed to quantify the adsorption of dissolved species onto the hydrous ferric oxide (HFO) surface, and contained numerous surface complexation reactions, including surface complexation reactions for uranyl (UO(2)(+2)) consisting of Hfo_sOUO(2)(+) and Hfo_wOUO(2)(+). However, these constants were not based upon experimentally obtained data, but rather were derived from linear free energy relationships (LFER) using log K(MOH) values. When compared to experimental data, the LFER-derived constants for uranyl were shown to overestimate adsorption by a factor of 10 in some cases. At least 14 uranyl HFO data sets have been previously published and were used to re-estimate constants by coupling the geochemical computer code PHREEQC with UCODE_2005, an automated parameter optimization program. Five uranyl-bearing surface complexation reactions were initially evaluated; the constants were optimized by allowing UCODE to incrementally vary selected log K(x)(int) values until the best fit to the experimental data was obtained. Assumptions consistent with the original DLM were retained. Changes to the K(1)(int) and K(2)(int) constants, and addition of uranyl monocarbonate and uranyl dicarbonate surface complexes, will update and correct the uranyl sorption reactions in this widely used database. PMID:20000518

  2. Ascorbic acid inhibits ferric nitrilotriacetate induction of ornithine decarboxylase, DNA synthesis, oxidative stress, and hepatotoxicity in rats.

    PubMed

    Ansar, S; Iqbal, M

    2015-11-01

    Ascorbic acid (AA) is a naturally occurring phenolic compound with antioxidant properties used in food, cosmetics, and pharmaceutical products. In this study, the effect of AA on ferric nitrilotriacetate (Fe-NTA)-induced hepatotoxicity in rats has been examined. Fe-NTA alone enhances ornithine decarboxylase activity to 4.5-fold and tritiated thymidine incorporation in DNA to 3.6-fold in livers compared with the corresponding saline-treated controls. The enhanced ornithine decarboxylase activity and DNA synthesis showed a reduction to 3.02- and 1.88-fold, respectively, at a higher dose of 2 mg AA per day per animal, compared with the Fe-NTA-treated groups. Fe-NTA treatment also enhanced the hepatic microsomal lipid peroxidation to 1.7-fold compared to saline-treated controls. These changes were reversed significantly in animals receiving pretreatment of AA. The present data shows that AA can reciprocate the toxic effects of Fe-NTA and can serve as a potent chemopreventive agent to suppress oxidant-induced tissue injury and hepatotoxicity in rats. PMID:23863956

  3. Application of citrate-stabilized gold-coated ferric oxide composite nanoparticles for biological separations

    NASA Astrophysics Data System (ADS)

    Hien Pham, Thao Thi; Cao, Cuong; Sim, Sang Jun

    Gold-coated magnetic nanoparticles were synthesized with size ranging from 15 to 40 nm using sodium citrates as the reducing agent. Oxidized magnetites (Fe 3O 4) fabricated by co-precipitation of Fe 2+ and Fe 3+ in strong alkaline solution were used as magnetic cores. The structures of gold (Au) shell and magnetic core (Au-Fe) were studied by transmission electron microscopy (TEM) image and energy dispersive spectroscopy (EDS) spectrum. Results from high-resolution X-ray diffraction (HR XRD) show that the Au-Fe oxide nanoparticles have a face-centered cubic shape with the crystalline faces of {1 1 1}. The Au-coated magnetic nanoparticles exhibited a surface plasmon resonance peak at 528 nm. The nanoparticles are well dispersed in distilled water. A 3000 G permanent magnet was successfully used for the separation of the functionalized nanoparticles. Magnetic properties of the nanoparticles were determined by magnetic force microscope (MFM) in nanometric resolution and vibrating sample magnetometer (VSM). Magnetic separation of biological molecules using Au-coated magnetic oxide composite nanoparticles was examined after attachment of protein immunoglobulin G (IgG) through electrostatic interactions. Using this method, separation was achieved with a maximum yield of 35% at an IgG concentration of 400 ng/ml.

  4. The formation, structure, and ageing of As-rich hydrous ferric oxide at the abandoned Sb deposit Pezinok (Slovakia)

    NASA Astrophysics Data System (ADS)

    Majzlan, Juraj; Lalinsk, Bronislava; Chovan, Martin; Jurkovi?, L.'ubomr; Milovsk, Stanislava; Gttlicher, Jrg

    2007-09-01

    The abandoned Sb deposit Pezinok in Slovakia is a significant source of As and Sb pollution that can be traced in the upper horizons of soils kilometers downstream. The source of the metalloids are two tailing impoundments which hold 380,000 m 3 of mining waste. The tailings and the discharged water have circumneutral pH values (7.0 0.6) because the acidity generated by the decomposition of the primary sulfides (pyrite, FeS 2; arsenopyrite, FeAsS; berthierite, FeSb 2S 4) is rapidly neutralized by the abundant carbonates. The weathering rims on the primary sulfides are iron oxides which act as very efficient scavengers of As and Sb (with up to 19.2 wt% As and 23.7 wt% Sb). In-situ ?-XANES experiments indicate that As in the weathering rims is fully oxidized (As 5+). The pore solutions in the impoundment body contain up to 81 ppm As and 2.5 ppm Sb. Once these solutions are discharged from the impoundments, they precipitate or deposit masses of As-rich hydrous ferric oxide (As-HFO) with up to 28.3 wt% As 2O 5 and 2.7 wt% Sb. All As-HFO samples are amorphous to X-rays. They contain Fe and As in their highest oxidation state and in octahedral and tetrahedral coordination, respectively, as suggested by XANES and EXAFS studies on Fe K and As K edges. The iron octahedra in the As-HFO share edges to form short single chains and the chains polymerize by sharing edges or corners with the adjacent units. The arsenate ions attach to the chains in a bidentate-binuclear and monodentate fashion. In addition, hydrogen-bonded complexes may exist to satisfy the bonding requirements of all oxygen atoms in the first coordination sphere of As 5+. Structural changes in the As-HFO samples were traced by chemical analyses and Fe EXAFS spectroscopy during an ageing experiment. As the samples age, As becomes more easily leachable. EXAFS spectra show a discernible trend of increasing number of Fe-Fe pairs at a distance of 3.3-3.5 , that is, increasing polymerization of the iron octahedra to form larger units with fewer adsorption sites. Therefore, although ferrihydrite is an excellent material for capturing arsenic, its use as a medium for a long-term storage of As has to be considered with a great caution because it will tend to release arsenic as it ages.

  5. The Formation, Structure, and Ageing of As-Rich Hydrous Ferric Oxide at the Abandoned Sb Deposit Pezinok (Slovakia)

    SciTech Connect

    Majzlan,J.; Lalinska, B.; Chovan, M.; Jurkovic, L.; Milovska, S.; Gottlicher, J.

    2007-01-01

    The abandoned Sb deposit Pezinok in Slovakia is a significant source of As and Sb pollution that can be traced in the upper horizons of soils kilometers downstream. The source of the metalloids are two tailing impoundments which hold {approx}380,000 m{sup 3} of mining waste. The tailings and the discharged water have circumneutral pH values (7.0 {+-} 0.6) because the acidity generated by the decomposition of the primary sulfides (pyrite, FeS{sub 2}; arsenopyrite, FeAsS; berthierite, FeSb{sub 2}S{sub 4}) is rapidly neutralized by the abundant carbonates. The weathering rims on the primary sulfides are iron oxides which act as very efficient scavengers of As and Sb (with up to 19.2 wt% As and 23.7 wt% Sb). In-situ {mu}-XANES experiments indicate that As in the weathering rims is fully oxidized (As{sup 5+}). The pore solutions in the impoundment body contain up to 81 ppm As and 2.5 ppm Sb. Once these solutions are discharged from the impoundments, they precipitate or deposit masses of As-rich hydrous ferric oxide (As-HFO) with up to 28.3 wt% As{sub 2}O{sub 5} and 2.7 wt% Sb. All As-HFO samples are amorphous to X-rays. They contain Fe and As in their highest oxidation state and in octahedral and tetrahedral coordination, respectively, as suggested by XANES and EXAFS studies on Fe K and As K edges. The iron octahedra in the As-HFO share edges to form short single chains and the chains polymerize by sharing edges or corners with the adjacent units. The arsenate ions attach to the chains in a bidentate-binuclear and monodentate fashion. In addition, hydrogen-bonded complexes may exist to satisfy the bonding requirements of all oxygen atoms in the first coordination sphere of As{sup 5+}. Structural changes in the As-HFO samples were traced by chemical analyses and Fe EXAFS spectroscopy during an ageing experiment. As the samples age, As becomes more easily leachable. EXAFS spectra show a discernible trend of increasing number of Fe-Fe pairs at a distance of 3.3-3.5 {angstrom}, that is, increasing polymerization of the iron octahedra to form larger units with fewer adsorption sites. Therefore, although ferrihydrite is an excellent material for capturing arsenic, its use as a medium for a long-term storage of As has to be considered with a great caution because it will tend to release arsenic as it ages.

  6. Arsenate Adsorption by Hydrous Ferric Oxide Nanoparticles Embedded in Cross-linked Anion Exchanger: Effect of the Host Pore Structure.

    PubMed

    Li, Hongchao; Shan, Chao; Zhang, Yanyang; Cai, Jianguo; Zhang, Weiming; Pan, Bingcai

    2016-02-10

    Three composite adsorbents were fabricated via confined growth of hydrous ferric oxide (HFO) nanoparticles within cross-linked anion exchangers (NS) of different pore size distributions to investigate the effect of host pore structure on the adsorption of As(V). With the decrease in the average pore size of the NS hosts from 38.7 to 9.2 nm, the mean diameter of the confined HFO nanoparticles was lessened from 31.4 to 11.6 nm as observed by transmission electron microscopy (TEM), while the density of active surface sites was increased due to size-dependent effect proved by potentiometric titration. The adsorption capacity of As(V) yielded by Sips model was elevated from 24.2 to 31.6 mg/g via tailoring the pore size of the NS hosts, and the adsorption kinetics was slightly accelerated with the decrease of pore size in background solution containing 500 mg/L of Cl(-). Furthermore, the enhanced adsorption of As(V) was achieved over a wide pH range from 3 to 10, as well as in the presence of competing anions including Cl(-), SO4(2-), HCO3(-), NO3(-) (up to 800 mg/L), and PO4(3-) (up to 10 mg P/L). In addition, the fixed-bed working capacity increased from 2200 to 2950 bed volumes (BV) owing to the size confinement effect, which did not have adverse effect on the desorption of As(V) as the cumulative desorption efficiency reached 94% with 10 BV of binary solution (5% NaOH + 5% NaCl) for all the three adsorbents. Therefore, this study provided a promising strategy to regulate the reactivity of the nanoparticles via the size confinement effect of the host pore structure. PMID:26765396

  7. Sorption kinetics of strontium in porous hydrous ferric oxide aggregates II. Comparison of experimental results and model predictions.

    PubMed

    Hofmann, Annette; van Beinum, Wendy; Meeussen, Johannes C L; Kretzschmar, Ruben

    2005-03-01

    In a previous paper, we introduced the Donnan diffusion model to describe cation diffusion into microporous solids with variably charged surfaces, such as hydrous ferric oxides (HFO). Here, we present experiments investigating slow diffusion and sorption of strontium by HFO aggregates with well-characterized porosity. Adsorption of protons and strontium at the HFO surface was evaluated by acid-base titration and batch adsorption experiments with dispersed HFO. The experimental data were fitted with a 1-pK basic Stern model including surface ion pair formation of Na(+) and NO(3)(-) and charge distribution for Sr surface complexes. Sorption-diffusion experiments were conducted in flow-through columns at controlled flow rates and at two different pH values, pH 4 and 7. Wet HFO aggregates, which were synthesized using a freezing and thawing method, were packed into chromatographic columns, pre-equilibrated to reach a constant pH, and then Sr breakthrough curves for adsorption and desorption of Sr were recorded. Strong retardation of Sr indicated that diffusion was sufficiently fast in a fraction of pores, so that sorption sites in these pores were rapidly accessible. Based on the analysis of NaNO(3) breakthrough curves, this rapidly accessible pore fraction was estimated to be 37% of the total aggregate pore volume at pH 4.0 and 72% at pH 7.0, respectively. Taking this into account, the Donnan diffusion model gave a good description of the experimental Sr breakthrough curves. Cation exclusion was correctly predicted at pH 4.0. At pH 7, the strong tailing of Sr breakthrough curves due to Sr diffusion into the smallest pores was very well simulated. The Donnan diffusion model proved adequate for pore sizes between approximately 2 and 5 nm, depending on pH and ionic strength. This category of pores was dominant in the HFO aggregates used in this work. PMID:15694421

  8. 21 CFR 184.1307 - Ferric sulfate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ferric sulfate. 184.1307 Section 184.1307 Food and... Substances Affirmed as GRAS 184.1307 Ferric sulfate. (a) Ferric sulfate (iron (III) sulfate, Fe2(SO4)3 CAS Reg. No. 10028-22-5) is a yellow substance that may be prepared by oxidizing iron (II) sulfate or...

  9. 21 CFR 184.1307 - Ferric sulfate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Ferric sulfate. 184.1307 Section 184.1307 Food and... Substances Affirmed as GRAS 184.1307 Ferric sulfate. (a) Ferric sulfate (iron (III) sulfate, Fe2(SO4)3 CAS Reg. No. 10028-22-5) is a yellow substance that may be prepared by oxidizing iron (II) sulfate or...

  10. 21 CFR 184.1307 - Ferric sulfate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Ferric sulfate. 184.1307 Section 184.1307 Food and... Substances Affirmed as GRAS 184.1307 Ferric sulfate. (a) Ferric sulfate (iron (III) sulfate, Fe2(SO4)3 CAS Reg. No. 10028-22-5) is a yellow substance that may be prepared by oxidizing iron (II) sulfate or...

  11. 21 CFR 184.1307 - Ferric sulfate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Ferric sulfate. 184.1307 Section 184.1307 Food and... Substances Affirmed as GRAS 184.1307 Ferric sulfate. (a) Ferric sulfate (iron (III) sulfate, Fe2(SO4)3 CAS Reg. No. 10028-22-5) is a yellow substance that may be prepared by oxidizing iron (II) sulfate or...

  12. Mechanical properties of nanophase materials

    SciTech Connect

    Siegel, R.W.; Fougere, G.E.

    1993-11-01

    It has become possible in recent years to synthesize new materials under controlled conditions with constituent structures on a nanometer size scale (below 100 nm). These novel nanophase materials have grain-size dependent mechanical properties significantly different than those of their coarser-grained counterparts. For example, nanophase metals are much stronger and apparently less ductile than conventional metals, while nanophase ceramics are more ductile and more easily formed than conventional ceramics. The observed mechanical property changes are related to grain size limitations and/or the large percentage of atoms in grain boundary environments; they can also be affected by such features as flaw populations, strains and impurity levels that can result from differing synthesis and processing methods. An overview of what is presently known about the mechanical properties of nanophase materials, including both metals and ceramics, is presented. Some possible atomic mechanisms responsible for the observed behavior in these materials are considered in light of their unique structures.

  13. Nuclear fuel elements made from nanophase materials

    DOEpatents

    Heubeck, N.B.

    1998-09-08

    A nuclear reactor core fuel element is composed of nanophase high temperature materials. An array of the fuel elements in rod form are joined in an open geometry fuel cell that preferably also uses such nanophase materials for the cell structures. The particular high temperature nanophase fuel element material must have the appropriate mechanical characteristics to avoid strain related failure even at high temperatures, in the order of about 3000 F. Preferably, the reactor type is a pressurized or boiling water reactor and the nanophase material is a high temperature ceramic or ceramic composite. Nanophase metals, or nanophase metals with nanophase ceramics in a composite mixture, also have desirable characteristics, although their temperature capability is not as great as with all-ceramic nanophase material. Combinations of conventional or nanophase metals and conventional or nanophase ceramics can be employed as long as there is at least one nanophase material in the composite. The nuclear reactor so constructed has a number of high strength fuel particles, a nanophase structural material for supporting a fuel rod at high temperature, a configuration to allow passive cooling in the event of a primary cooling system failure, an ability to retain a coolable geometry even at high temperatures, an ability to resist generation of hydrogen gas, and a configuration having good nuclear, corrosion, and mechanical characteristics. 5 figs.

  14. Nuclear fuel elements made from nanophase materials

    DOEpatents

    Heubeck, Norman B.

    1998-01-01

    A nuclear reactor core fuel element is composed of nanophase high temperature materials. An array of the fuel elements in rod form are joined in an open geometry fuel cell that preferably also uses such nanophase materials for the cell structures. The particular high temperature nanophase fuel element material must have the appropriate mechanical characteristics to avoid strain related failure even at high temperatures, in the order of about 3000.degree. F. Preferably, the reactor type is a pressurized or boiling water reactor and the nanophase material is a high temperature ceramic or ceramic composite. Nanophase metals, or nanophase metals with nanophase ceramics in a composite mixture, also have desirable characteristics, although their temperature capability is not as great as with all-ceramic nanophase material. Combinations of conventional or nanophase metals and conventional or nanophase ceramics can be employed as long as there is at least one nanophase material in the composite. The nuclear reactor so constructed has a number of high strength fuel particles, a nanophase structural material for supporting a fuel rod at high temperature, a configuration to allow passive cooling in the event of a primary cooling system failure, an ability to retain a coolable geometry even at high temperatures, an ability to resist generation of hydrogen gas, and a configuration having good nuclear, corrosion, and mechanical characteristics.

  15. Sodium Ferric Gluconate Injection

    MedlinePLUS

    Sodium ferric gluconate injection is used to treat iron-deficiency anemia (a lower than normal number of ... are also receiving the medication epoetin (Epogen, Procrit). Sodium ferric gluconate injection is in a class of ...

  16. 21 CFR 73.1298 - Ferric ammonium ferrocyanide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...) Identity. (1) The color additive ferric ammonium ferrocyanide is the blue pigment obtained by oxidizing... with smaller amounts of ferric ferrocyanide and ferric sodium ferrocyanide. (2) Color additive mixtures... subpart as safe and suitable for use in color additive mixtures for coloring drugs. (b)...

  17. Interactions between substrates and the haem-bound nitric oxide of ferric and ferrous bacterial nitric oxide synthases

    PubMed Central

    Chartier, FranoisJ.M.; Couture, Manon

    2006-01-01

    We report here the resonance Raman spectra of the FeIIINO and FeIINO complexes of the bacterial NOSs (nitric oxide synthases) from Staphylococcus aureus and Bacillus subtilis. The haemNO complexes of these bacterial NOSs displayed FeNO frequencies similar to those of the mammalian NOSs, in presence and absence of L-arginine, indicating that haem-bound NO and L-arginine had similar haem environments in bacterial and mammalian NOSs. The only notable difference between the two types of NOS was the lack of change in FeNO frequencies of the FeIIINO complexes upon (6R) 5,6,7,8-tetrahydro-L-biopterin binding to bacterial NOSs. We report, for the first time, the characterization of NO complexes with NOHA (N?-hydroxy-L-arginine), the substrate used in the second half of the catalytic cycle of NOSs. In the FeIIINO complexes, both L-arginine and NOHA induced the FeNO bending mode at nearly the same frequency as a result of a steric interaction between the substrates and the haem-bound NO. However, in the FeIINO complexes, the FeNO bending mode was not observed and the ?Fe?NO mode displayed a 5cm?1 higher frequency in the complex with NOHA than in the complex with L-arginine as a result of direct interactions that probably involve hydrogen bonds. The different behaviour of the substrates in the FeIINO complexes thus reveal that the interactions between haem-bound NO and the substrates are finely tuned by the geometry of the Fe-ligand structure and are relevant to the use of the FeIINO complex as a model of the oxygenated complex of NOSs. PMID:16970546

  18. Preparation of ferric tungstate and its catalytic behavior toward methanol

    SciTech Connect

    Harrison, W.T.A.; Cheetham, A.K.; Chowdhry, U.; Machiels, C.J.; Sleight, A.W.

    1985-11-01

    Pure ferric tungstate, Fe/sub 2/(WO/sub 4/)/sub 3/, has been prepared and characterized for the first time. Ferric tungstate has a structure very similar to that of ferric molybdate with a unit cell volume about 1.5% larger. Decomposition to Fe/sub 2/WO/sub 6/ and WO/sub 3/ occurs at about 600/sup 0/C. Ferric tungstate was tested as catalyst for the selective oxidation of methanol and shown to have very different properties from ferric molybdate for this reaction. Whereas over the molybdate the predominant reaction is oxidation of methanol to formaldehyde, over the tungstate it is dehydration to dimethyl ether.

  19. Ferric nitrilotriacetate (Fe-NTA)-induced reactive oxidative species protects human hepatic stellate cells from apoptosis by regulating Bcl-2 family proteins and mitochondrial membrane potential

    PubMed Central

    Liu, Mei; Li, Shu-Jie; Xin, Yong-Ning; Ji, Shu-Sheng; Xie, Rui-Jin; Xuan, Shi-Ying

    2015-01-01

    Reactive oxidative species (ROS)-induced apoptosis of human hepatic stellate (HSC) is one of the treatments for liver fibrosis. However, how ROS (reactive oxygen species) affect HSC apoptosis and liver fibrosis is still unknown. In our study, ROS in human HSC cell line LX-2 was induced by ferric nitrilotriacetate (Fe-NTA) and assessed by superoxide dismutase (SOD) activity and methane dicarboxylic aldehyde (MDA) level. We found that in LX2 cells Fe-NTA induced notable ROS, which played a protective role in HSCs cells apoptosis by inhibiting Caspase-3 activation. Fe-NTA-induced ROS increased mRNA and protein level of anti-apoptosis Bcl-2 and decreased mRNA protein level of pro-apoptosis gene Bax, As a result, maintaining mitochondrial membrane potential of HSCs. Fe-NTA-induced ROS play a protective role in human HSCs by regulating Bcl-2 family proteins and mitochondrial membrane potential. PMID:26770403

  20. Heterogeneous catalytic ozonation of biologically pretreated Lurgi coal gasification wastewater using sewage sludge based activated carbon supported manganese and ferric oxides as catalysts.

    PubMed

    Zhuang, Haifeng; Han, Hongjun; Hou, Baolin; Jia, Shengyong; Zhao, Qian

    2014-08-01

    Sewage sludge of biological wastewater treatment plant was converted into sewage sludge based activated carbon (SBAC) with ZnCl? as activation agent, which supported manganese and ferric oxides as catalysts (including SBAC) to improve the performance of ozonation of real biologically pretreated Lurgi coal gasification wastewater. The results indicated catalytic ozonation with the prepared catalysts significantly enhanced performance of pollutants removal and the treated wastewater was more biodegradable and less toxic than that in ozonation alone. On the basis of positive effect of higher pH and significant inhibition of radical scavengers in catalytic ozonation, it was deduced that the enhancement of catalytic activity was responsible for generating hydroxyl radicals and the possible reaction pathway was proposed. Moreover, the prepared catalysts showed superior stability and most of toxic and refractory compounds were eliminated at successive catalytic ozonation runs. Thus, the process with economical, efficient and sustainable advantages was beneficial to engineering application. PMID:24907577

  1. The nanophase iron mineral(s) in Mars soil

    NASA Technical Reports Server (NTRS)

    Banin, A.; Ben-Shlomo, T.; Margulies, L.; Blake, D. F.; Mancinelli, R. L.; Gehring, A. U.

    1993-01-01

    A series of surface-modified clays containing nanophase (np) iron oxide/oxyhydroxides of extremely small particle sizes, with total iron contents as high as found in Mars soil, were prepared by iron deposition on the clay surface from ferrous chloride solution. Comprehensive studies of the iron mineralogy in these "Mars-soil analogs" were conducted using chemical extractions, solubility analyses, pH and redox, x ray and electron diffractometry, electron microscopic imaging, specific surface area and particle size determinations, differential thermal analyses, magnetic properties characterization, spectral reflectance, and Viking biology simulation experiments. The clay matrix and the procedure used for synthesis produced nanophase iron oxides containing a certain proportion of divalent iron, which slowly converts to more stable, fully oxidized iron minerals. The clay acted as an effective matrix, both chemically and sterically, preventing the major part of the synthesized iron oxides from ripening, i.e., growing and developing larger crystals. The precipitated iron oxides appear as isodiametric or slightly elongated particles in the size range 1-10 nm, having large specific surface area. The noncrystalline nature of the iron compounds precipitated on the surface of the clay was verified by their complete extractability in oxalate. Lepidocrocite (gamma-FeOOH) was detected by selected area electron diffraction. It is formed from a double iron Fe(II)/Fe(III) hydroxy mineral such as "green rust," or ferrosic hydroxide. Magnetic measurements suggested that lepidocrocite converted to the more stable maghemite (gamma-Fe2O3) by mild heat treatment and then to nanophase hematite (alpha-Fe2O3) by extensive heat treatment. After mild heating, the iron-enriched clay became slightly magnetic, to the extent that it adheres to a hand-held magnet, as was observed with Mars soil. The chemical reactivity of the iron-enriched clays strongly resembles, and offers a plausible mechanism for, the somewhat puzzling observations of the Viking biology experiments. Their unique chemical reactivities are attributed to the combined catalytic effects of the iron oxide/oxyhydroxides and silicate phase surfaces. The reflectance spectrum of the clay-iron preparations in the visible range is generally similar to the reflectance curves of bright regions on Mars. This strengthens the evidence for the predominance of nanophase iron oxides/oxyhydroxides in Mars soil. The mode of formation of these nanophase iron oxides on Mars is still unknown. It is puzzling that despite the long period of time since aqueous weathering took place on Mars, they have not developed from their transitory stage to well-crystallized end-members. The possibility is suggested that these phases represent a continuously on-going, extremely slow weathering process.

  2. The nanophase iron mineral(s) in Mars soil.

    PubMed

    Banin, A; Ben-Shlomo, T; Margulies, L; Blake, D F; Mancinelli, R L; Gehring, A U

    1993-11-25

    A series of surface-modified clays containing nanophase (np) iron oxide/oxyhydroxides of extremely small particle sizes, with total iron contents as high as found in Mars soil, were prepared by iron deposition on the clay surface from ferrous chloride solution. Comprehensive studies of the iron mineralogy in these "Mars-soil analogs" were conducted using chemical extractions, solubility analyses, pH and redox, x ray and electron diffractometry, electron microscopic imaging, specific surface area and particle size determinations, differential thermal analyses, magnetic properties characterization, spectral reflectance, and Viking biology simulation experiments. The clay matrix and the procedure used for synthesis produced nanophase iron oxides containing a certain proportion of divalent iron, which slowly converts to more stable, fully oxidized iron minerals. The clay acted as an effective matrix, both chemically and sterically, preventing the major part of the synthesized iron oxides from ripening, i.e., growing and developing larger crystals. The precipitated iron oxides appear as isodiametric or slightly elongated particles in the size range 1-10 nm, having large specific surface area. The noncrystalline nature of the iron compounds precipitated on the surface of the clay was verified by their complete extractability in oxalate. Lepidocrocite (gamma-FeOOH) was detected by selected area electron diffraction. It is formed from a double iron Fe(II)/Fe(III) hydroxy mineral such as "green rust," or ferrosic hydroxide. Magnetic measurements suggested that lepidocrocite converted to the more stable maghemite (gamma-Fe2O3) by mild heat treatment and then to nanophase hematite (alpha-Fe2O3) by extensive heat treatment. After mild heating, the iron-enriched clay became slightly magnetic, to the extent that it adheres to a hand-held magnet, as was observed with Mars soil. The chemical reactivity of the iron-enriched clays strongly resembles, and offers a plausible mechanism for, the somewhat puzzling observations of the Viking biology experiments. Their unique chemical reactivities are attributed to the combined catalytic effects of the iron oxide/oxyhydroxides and silicate phase surfaces. The reflectance spectrum of the clay-iron preparations in the visible range is generally similar to the reflectance curves of bright regions on Mars. This strengthens the evidence for the predominance of nanophase iron oxides/oxyhydroxides in Mars soil. The mode of formation of these nanophase iron oxides on Mars is still unknown. It is puzzling that despite the long period of time since aqueous weathering took place on Mars, they have not developed from their transitory stage to well-crystallized end-members. The possibility is suggested that these phases represent a continuously on-going, extremely slow weathering process. PMID:11539182

  3. Antioxidant and nephroprotective potential of butylated hydroxyanisole against ferric nitrilotriacetate-induced oxidative stress and early tumor events.

    PubMed

    Ansar, S; Iqbal, M

    2016-04-01

    The present study was aimed to study protective effect of butylated hydroxyanisole (BHA), a phenolic antioxidant used in foods on ferric nitrilotriacetate (Fe-NTA)-induced nephrotoxicity. Male albino rats of Wistar strain (4-6 weeks old) weighing 125-150 g were used in this study. Animals were given a single dose of Fe-NTA (9 mg kg(-1) body weight) after treatment with BHA (1 and 2 mg animal(-1) day(-1)). Fe-NTA treatment enhanced ornithine decarboxylase (ODC) activity to 5.3-fold, and [(3)H]-thymidine incorporation in DNA to 2.5-fold in kidney compared with the corresponding saline-treated control, whereas glutathione (GSH) levels and the activities of antioxidant enzymes decreased to a range of 2- to 2.5-fold in kidney. These changes were reversed significantly in animals receiving a pretreatment of BHA. The enhanced ODC activity and DNA synthesis showed a reduction to 2.12-fold and 1.15-fold, respectively, at a higher dose of 2 mg BHA day(-1) animal(-1), compared with the Fe-NTA-treated groups. Pretreatment with BHA prior to Fe-NTA treatment increased GSH and the activities of antioxidant enzymes to a range of 1.5- to 2-fold in kidney. The results indicate that BHA suppresses Fe-NTA-induced nephrotoxicity in male Wistar rats. PMID:26078281

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

    PubMed

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

    2016-01-01

    Iron (Fe) is abundant in soils but generally poorly soluble. Plants, with the exception of Graminaceae, take up Fe using an Fe(III)-chelate reductase coupled to an Fe(II) transporter. Whether or not nongraminaceous species can convert scarcely soluble Fe(III) forms into soluble Fe forms has deserved little attention so far. We have used Beta vulgaris, one among the many species whose roots secrete flavins upon Fe deficiency, to study whether or not flavins are involved in Fe acquisition. Flavins secreted by Fe-deficient plants were removed from the nutrient solution, and plants were compared with Fe-sufficient plants and Fe-deficient plants without flavin removal. Solubilization of a scarcely soluble Fe(III)-oxide was assessed in the presence or absence of flavins, NADH (nicotinamide adenine dinucleotide, reduced form) or plant roots, and an Fe(II) trapping agent. The removal of flavins from the nutrient solution aggravated the Fe deficiency-induced leaf chlorosis. Flavins were able to dissolve an Fe(III)-oxide in the presence of NADH. The addition of extracellular flavins enabled roots of Fe-deficient plants to reductively dissolve an Fe(III)-oxide. We concluded that root-secretion of flavins improves Fe nutrition in B. vulgaris. Flavins allow B. vulgaris roots to mine Fe from Fe(III)-oxides via reductive mechanisms. PMID:26351005

  5. Labeling of the pathogenic bacterium Staphylococcus aureus with gold or ferric oxide-core nanoparticles highlights new capabilities for investigation of host-pathogen interactions.

    PubMed

    Depke, Maren; Surmann, Kristin; Hildebrandt, Petra; Jehmlich, Nico; Michalik, Stephan; Stanca, Sarmiza E; Fritzsche, Wolfgang; Völker, Uwe; Schmidt, Frank

    2014-02-01

    Throughout the world, infections caused by bacteria such as Staphylococcus aureus are a major cause of morbidity and mortality. In order to gain some understanding of the complicated physiological link between host and pathogen, modern techniques such as confocal microscopy and sophisticated OMICs technologies are suitable. However, labeling of pathogens such as S. aureus with green fluorescent protein, for example, or the generation of a reliable antibody, which are prerequisites for the application of reproducible isolation techniques, does not always succeed. Here, we present a universal approach for monitoring pathogen traffic after internalization into host cells by fluorescence microscopy and for isolation of bacteria from host-pathogen interaction assays using gold or ferric oxide-core, poly(vinyl alcohol) coated, and fluorescence-labeled nanoparticles (NP). The incubation of S. aureus HG001 with those NP had only minor effects on the bacterial growth in vitro. Quantitative proteome analysis after 24 h of NP incubation revealed that presence of NP provoked only marginal changes in the proteome pattern. The method presented enabled us to investigate the behavior of S. aureus HG001 during infection of S9 human epithelial cells by means of fluorescence microscopy and proteomics using magnetic separation or cell sorting. PMID:24347542

  6. Mineralogical confirmation of a near-P:Fe = 1:2 limiting stoichiometric ratio in colloidal P-bearing ferrihydrite-like hydrous ferric oxide

    NASA Astrophysics Data System (ADS)

    Thibault, Pierre-Jean; Rancourt, Denis G.; Evans, R. James; Dutrizac, John E.

    2009-01-01

    We present a chemical and mineralogical explanation, derived from powder X-ray diffraction and Mssbauer spectroscopy measurements of synthetic samples, of the P:Fe = 1:2 limiting ratio of P incorporation (as PO 4) that was previously observed in natural aquatic oxic iron precipitates. The 57Fe Mssbauer hyperfine parameters are interpreted with the help of state-of-the-art ab initio electronic structure calculations. We find that there is a strong tendency for solid solution P-Fe mixing in the P-bearing hydrous ferric oxide (P-HFO) aqueous coprecipitate system, interpreted as occurring between the P-free (ferrihydrite) end-member and an inferred P:Fe = 1:2 end-member beyond which P is not incorporated in the structure of the P-HFO solid. Up to and somewhat beyond the limiting end-member P:Fe ratio, all available P is scavenged by the coprecipitation reaction, suggesting strong P-Fe complexation in the precipitation-precursor dissolved species. The P-HFO solids are more stable (i.e., have stronger chemical bonds) than the P-free ferrihydrite end-member. We show that in coprecipitation the P specifically incorporates within the nanoparticle structure rather than complexing to the nanoparticle surface. Our results are relevant to the question of the mechanisms of coupling between the Fe and P cycles in natural aqueous environments and highlight a strong affinity between Fe and P in aqueous environments.

  7. Low electrical potential anode modified with Fe/ferric oxide and its application in marine benthic microbial fuel cell with higher voltage and power output

    NASA Astrophysics Data System (ADS)

    Fu, Yubin; Xu, Qian; Zai, Xuerong; Liu, Yuanyuan; Lu, Zhikai

    2014-01-01

    Low voltage and power output limit the widespread application of marine benthic microbial fuel cell (BMFCs). To increase the cell power, a Fe/Ferric oxide modified anode fabricating by electrolytic deposition is reported here. The novel anode has a lower surface contact angle and higher wettability, which favors the adhesion of bacteria. It is firstly demonstrated that the electrical potential of the modified anode is about -775 mV, much lower than that of the plain graphite (about -450 mV). Open circuit potential of BMFC with the modified anode is about 1050 ± 50 mV, while the potential for the plain cells is only 700 ± 50 mV. In comparison with the plain graphite, the modified anode presents a 393-fold exchange current density and a higher kinetic activity. The output power reaches 7.4 × 10-2 mW cm-2, 17.4-fold higher than that of the plain graphite. A composite mechanism of both chemical and microbial enhancement of the modified anode is proposed to explain its excellent electrochemical performance. The modified anode has potential for high-power output cell and novel voltage-booster design to make the BMFC utilization feasibility.

  8. Isolation and characterization of Acidicaldus organivorus, gen. nov., sp. nov.: a novel sulfur-oxidizing, ferric iron-reducing thermo-acidophilic heterotrophic Proteobacterium.

    PubMed

    Johnson, D Barrie; Stallwood, Bethan; Kimura, Sakurako; Hallberg, Kevin B

    2006-04-01

    Thermo-acidophilic prokaryotes isolated from geothermal sites in Yellowstone National Park were identified as novel alpha-Proteobacteria, distantly related (approximately 93% 16S rRNA gene identity) to the mesophilic acidophile Acidisphaera rubrifaciens. One of these isolates (Y008) was shown to be more thermophilic than all previously characterized acidophilic proteobacteria, with a temperature optimum for growth between 50 and 55 degrees C and a temperature maximum of 65 degrees C. Growth was observed in media maintained at pH between 1.75 and 3.0 and was fastest at pH between 2.5 and 3.0. The G + C content of Y008 was 71.8+/-0.9 mol%. The acidophile was able to grow heterotrophically on a range of organic substrates, including various monosaccharides, alcohols and amino acids and phenol, though growth on single organic compounds required the provision of one or more growth factors. The isolate oxidized sulfur to sulfuric acid in media containing yeast extract, but was not capable of autotrophic growth with sulfur as energy source. Growth occurred under aerobic conditions and also in the absence of oxygen via anaerobic respiration using ferric iron as terminal electron acceptor. Based on these genotypic and phenotypic traits, it is proposed that Y008 represents the type species of Acidicaldus organivorus, gen. nov., sp. nov. PMID:16432746

  9. Selective mineralization of microbes in Fe-rich precipitates (jarosite, hydrous ferric oxides) from acid hot springs in the Waiotapu geothermal area, North Island, New Zealand

    NASA Astrophysics Data System (ADS)

    Jones, Brian; Renaut, Robin W.

    2007-01-01

    A group of small springs that are informally called "Orange Spring", located near Hakereteke Stream in the northern part of the Waiotapu geothermal area, feed hot ( 80 C), acidic (pH: 2.1 - 2.4), As-rich sulfate waters into a discharge channel that is up to 25 cm deep. Submerged reddish-brown precipitates on the channel floor are formed largely of noncrystalline As-rich hydrous ferric oxide (HFO: mainly goethite), poorly crystalline lepidocrocite, and crystalline jarosite. Well-preserved coccoid and rod-shaped microbes are found in the As-rich HFO, but not in the lepidocrocite or jarosite. The jarosite was probably precipitated when the water had a low pH (< 3) and high SO 4 content, whereas the goethite and lepidocrocite were probably precipitated when the water had a slightly higher pH (> 4) and lower SO 4 content. The fluctuations in the pH and SO 4 content, which led to precipitation of the different mineral phases, may reflect mixing of the spring water with stream water that flowed through the channel when Hakereteke Stream was in flood stage. The goethite probably formed when coccoid and rod-shaped bacteria ( Acidithiobacillus ferrooxidans?) mediated rapid oxidization of the Fe 2+ to Fe 3+ that was then immediately coprecipitated with the As. Such rapid precipitation promoted mineralization of the microbes. The lack of mineralized microbes and the lower As in the lepidocrocite and jarosite may reflect precipitation rates that were slower than the decay rates of the microbes, or ecological factors that limited their growth.

  10. Combined Hydrous Ferric Oxide and Quaternary Ammonium Surfactant Tailoring of Granular Activated Carbon for Concurrent Arsenate and Perchlorate Removal

    SciTech Connect

    Jang, M.; Cannon, F; Parette, R; Yoon, S; Chen, W

    2009-01-01

    Activated carbon was tailored with both iron and quaternary ammonium surfactants so as to concurrently remove both arsenate and perchlorate from groundwater. The iron (hydr)oxide preferentially removed the arsenate oxyanion but not perchlorate; while the quaternary ammonium preferentially removed the perchlorate oxyanion, but not the arsenate. The co-sorption of two anionic oxyanions via distinct mechanisms has yielded intriguing phenomena. Rapid small-scale column tests (RSSCTs) with these dually prepared media employed synthetic waters that were concurrently spiked with arsenate and perchlorate; and these trial results showed that the quaternary ammonium surfactants enhanced arsenate removal bed life by 25-50% when compared to activated carbon media that had been preloaded merely with iron (hydr)oxide; and the surfactant also enhanced the diffusion rate of arsenate per the Donnan effect. The authors also employed natural groundwater from Rutland, MA which contained 60 microg/L As and traces of silica, and sulfate; and the authors spiked this with 40 microg/L perchlorate. When processing this water, activated carbon that had been tailored with iron and cationic surfactant could treat 12,500 bed volumes before 10 microg/L arsenic breakthrough, and 4500 bed volumes before 6 microg/L perchlorate breakthrough. Although the quaternary ammonium surfactants exhibited only a slight capacity for removing arsenate, these surfactants did facilitate a more favorably positively charged avenue for the arsenate to diffuse through the media to the iron sorption site (i.e. via the Donnan effect).

  11. Effect of La{sub 2}O{sub 3}-treatment on textural and solid-solid interactions in ferric/cobaltic oxides system

    SciTech Connect

    Fagal, Gehan A.; Badawy, Abdelrahman A.; Hassan, Neven A.; El-Shobaky, Gamil A.

    2012-10-15

    Pure and La{sub 2}O{sub 3}-containing (0.75-3.0 mol%) Fe{sub 2}O{sub 3}/Co{sub 3}O{sub 4} solids were prepared by thermal treatment of their carbonates at 500-700 Degree-Sign C. The produced solids were characterized using XRD, HRTEM, EDX and nitrogen adsorption at -196 Degree-Sign C. The results revealed that pure solids calcined at 600 and 700 Degree-Sign C consisted of nanosized CoFe{sub 2}O{sub 4} phase, while pure mixed solids calcined at 500 Degree-Sign C consisted of trace amount of CoFe{sub 2}O{sub 4} and unreacted Fe{sub 2}O{sub 3}, Co{sub 3}O{sub 4} phases. The presence of 0.75 mol% La{sub 2}O{sub 3} enhanced solid-solid interaction between Fe{sub 2}O{sub 3} and Co{sub 3}O{sub 4} at 500 Degree-Sign C yielding CoFe{sub 2}O{sub 4}. The ferrite phase existed also in all mixed oxides upon treated with La{sub 2}O{sub 3} besides LaCoO{sub 3} phase. LaCoO{sub 3} existed as a major phase in all mixed oxides treated with 3 mol% La{sub 2}O{sub 3}. La{sub 2}O{sub 3}-treatment modified the crystallite size of all phases present to an extent dependent on calcination temperature and amount of La{sub 2}O{sub 3} content. This treatment decreased effectively the S{sub BET} of all mixed solids. - Graphical Abstract: TEM photographs of pure mixed oxides calcined at 500 Degree-Sign C. Highlights: Black-Right-Pointing-Pointer Cobalt ferrite exhibit chemical stability, low electric loss and high coercivity. Black-Right-Pointing-Pointer Cobalt ferrite is used in microwave devices, computer memories and magnetic storage. Black-Right-Pointing-Pointer Solid-solid interactions in ferric/cobaltic oxides system were investigated. Black-Right-Pointing-Pointer La{sub 2}O{sub 3}-treatment modified surface compositions of the system investigated. Black-Right-Pointing-Pointer All phases present in various solids existed as nanosized solids.

  12. Ferric iron amendment increases Fe(III)-reducing microbial diversity and carbon oxidation in on-site wastewater systems.

    PubMed

    Azam, Hossain M; Finneran, Kevin T

    2013-01-01

    Onsite wastewater systems, or septic tanks, serve approximately 25% of the United States population; they are therefore a critical component of the total carbon balance for natural water bodies. Septic tanks operate under strictly anaerobic conditions, and fermentation is the dominant process driving carbon transformation. Nitrate, Fe(III), and sulfate reduction may be operating to a limited extent in any given septic tank. Electron acceptor amendments will increase carbon oxidation, but nitrate is toxic and sulfate generates corrosive sulfides, which may damage septic system infrastructure. Fe(III) reducing microorganisms transform all major classes of organic carbon that are dominant in septic wastewater: low molecular weight organic acids, carbohydrate monomers and polymers, and lipids. Fe(III) is not toxic, and the reduction product Fe(II) is minimally disruptive if the starting Fe(III) is added at 50-150 mg L(-1). We used (14)C radiolabeled acetate, lactate, propionate, butyrate, glucose, starch, and oleic acid to demonstrate that short and long-term carbon oxidation is increased when different forms of Fe(III) are amended to septic wastewater. The rates of carbon mineralization to (14)CO(2) increased 2-5 times (relative to unamended systems) in the presence of Fe(III). The extent of mineralization reached 90% for some carbon compounds when Fe(III) was present, compared to levels of 50-60% in the absence of Fe(III). (14)CH(4) was not generated when Fe(III) was added, demonstrating that this strategy can limit methane emissions from septic systems. Amplified 16S rDNA restriction analysis indicated that unique Fe(III)-reducing microbial communities increased significantly in Fe(III)-amended incubations, with Fe(III)-reducers becoming the dominant microbial community in several incubations. The form of Fe(III) added had a significant impact on the rate and extent of mineralization; ferrihydrite and lepidocrocite were favored as solid phase Fe(III) and chelated Fe(III) (with nitrilotriacetic acid or EDTA) as soluble Fe(III) forms. PMID:23062939

  13. Ferric Tourmaline from Mexico.

    PubMed

    Mason, B; Donnay, G; Hardie, L A

    1964-04-01

    Dark brown crystals, up to 10 mm long, occur in rhyolite at Mexquitic, San Luis Potosi, Mexico. They are short prismatic, showing {1120}, {3030}, {1011}, {0221}, with c/a 0.4521, measured with a goniometer, and distinct {1120} cleavage. With an unusual combination of cell dimensions, high density, high refractive indices, and extreme birefringence, this tourmaline falls outside the known elbaite-schorl and schorl-dravite series. A chemical analysis, recalculated on the basis of cell volume and density, gives close to the theoretical 150 atoms per cell, whether the iron is ferrous or ferric, but the physical properties indicate a ferric tourmaline. PMID:17729799

  14. Formation, reactivity, and aging of ferric oxide particles formed from Fe(II) and Fe(III) sources: Implications for iron bioavailability in the marine environment

    NASA Astrophysics Data System (ADS)

    Bligh, Mark W.; Waite, T. David

    2011-12-01

    Freshly formed amorphous ferric oxides (AFO) in the water column are potentially highly reactive, but with reactivity declining rapidly with age, and have the capacity to partake in reactions with dissolved species and to be a significant source of bioavailable iron. However, the controls on reactivity in aggregated oxides are not well understood. Additionally, the mechanism by which early rapid aging occurs is not clear. Aging is typically considered in terms of changes in crystallinity as the structure of an iron oxide becomes more stable and ordered with time thus leading to declining reactivity. However, there has been recognition of the role that aggregation can play in determining reactivity, although it has received limited attention. Here, we have formed AFO in seawater in the laboratory from either an Fe(II) or Fe(III) source to produce either AFO(II) or AFO(III). The changes in reactivity of these two oxides following formation was measured using both ligand-promoted dissolution (LPD) and reductive dissolution (RD). The structure of the two oxides was examined using light scattering and X-ray adsorption techniques. The dissolution rate of AFO(III) was greater than that of AFO(II), as measured by both dissolution techniques, and could be attributed to both the less ordered molecular structure and smaller primary particle size of AFO(III). From EXAFS analysis shortly (90 min) following formation, AFO(II) and AFO(III) were shown to have the same structure as aged lepidocrocite and ferrihydrite respectively. Both oxides displayed a rapid decrease in dissolution rate over the first hours following formation in a pattern that was very similar when normalised. The early establishment and little subsequent change of crystal structure for both oxides undermined the hypothesis that increasing crystallinity was responsible for early rapid aging. Also, an aging model describing this proposed process could only be fitted to the data with kinetic parameters that were inconsistent with such a mechanism. The similar aging patterns and existence of diffusion limited cluster aggregation (DLCA) suggested that loss of Fe centre accessibility due to aggregation is the likely cause of early rapid aging of AFO. A simple model describing the loss of surface area during the aggregate growth, measured using dynamic light scattering (DLS), produced aging patterns that matched the reactivity loss of AFO(III) measured using RD but not LPD. The difference between the two measures of dissolution rate could not be explained, but indicated that different measures of reactivity respond differentially to various parameters controlling reactivity. Analysis of aggregate structure using aggregation kinetics and static light scattering (SLS) suggested that restructuring during aggregation was occurring at an aggregate level for AFO(III), but only minimally so for AFO(II). While our investigations support the contention that aggregation is responsible for early rapid aging, the role of aggregate structure is remains unclear.

  15. Nanophase materials assembled from clusters

    SciTech Connect

    Siegel, R.W.

    1992-02-01

    The preparation of metal and ceramic atom clusters by means of the gas-condensation method, followed by their in situ collection and consolidation under high-vacuum conditions, has recently led to the synthesis of a new class of ultrafine-grained materials. These nanophase materials, with typical average grain sizes of 5 to 50 nm and, hence, a large fraction of their atoms in interfaces, exhibit properties that are often considerably improved relative to those of conventional materials. Furthermore, their synthesis and processing characteristics should enable the design of new materials with unique properties. Some examples are ductile ceramics that can be formed and sintered to full density at low temperatures without the need for binding or sintering aids, and metals with dramatically increased strength. The synthesis of these materials is briefly described along with what is presently known of their structure and properties. Their future impact on materials science and technology is also considered.

  16. Calorimetry of Nanophases of Macromolecules

    NASA Astrophysics Data System (ADS)

    Wunderlich, Bernhard

    2007-06-01

    The thermodynamic description of polymeric systems is summarized based on 50 years of gathering experimental information with adiabatic, differential-scanning, and temperature-modulated calorimetry. This experience has led to a description of macro- to micro- to nano-phases with macromolecules able to traverse the phase boundaries and decouple at the surfaces, resulting in different thermodynamic properties for the separated parts of the molecule. A typical thermodynamic characterization of semicystalline polymers is that of a globally metastable system with locally reversible processes. Unique phenomena in polymers include the ability of semicrystalline polymers to undergo cold crystallization and molecular nucleation, possess thermally generated point defects and rigid-amorphous fractions, and have amorphous to mesophasic to crystalline macroconformations with glass, ordering, and disordering transitions in all three structures. To describe such multifaceted systems, special combinations of equilibrium, and irreversible thermodynamics as well as statistical and quantum mechanics are necessary. Only then is it possible to handle violations of phase rules, changes of properties when approaching nanophase dimensions, local reversibility, and enthalpy relaxation. The enthalpy relaxation in polymers originates in the cooperativeness of conformational motion and the interferences of processes of different time scales. The experiments to identify the effects of the different molecular motions from typical vibrational time scales of picoseconds to cooperative, large-amplitude rearrangements of up to megaseconds span heating rates of thousands of Ks-1 with superfast chip calorimeters to many hours for slow, quasi-isothermal analysis by temperature-modulated differential scanning calorimetry (TMDSC). Selected examples of this far-reaching thermal characterization will be presented.

  17. Defect Clustering and Nano-Phase Structure Characterization of Multi-Component Rare Earth Oxide Doped Zirconia-Yttria Thermal Barrier Coatings

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming; Chen, Yuan L.; Miller, Robert A.

    2003-01-01

    Advanced oxide thermal barrier coatings have been developed by incorporating multi-component rare earth oxide dopants into zirconia-yttria to effectively promote the creation of the thermodynamically stable, immobile oxide defect clusters and/or nano-scale phases within the coating systems. The presence of these nano-sized defect clusters has found to significantly reduce the coating intrinsic thermal conductivity, improve sintering resistance, and maintain long-term high temperature stability. In this paper, the defect clusters and nano-structured phases, which were created by the addition of multi-component rare earth dopants to the plasma-sprayed and electron-beam physical vapor deposited thermal barrier coatings, were characterized by high-resolution transmission electron microscopy (TEM). The defect cluster size, distribution, crystallographic and compositional information were investigated using high-resolution TEM lattice imaging, selected area diffraction (SAD), electron energy-loss spectroscopy (EELS) and energy dispersive spectroscopy (EDS) analysis techniques. The results showed that substantial defect clusters were formed in the advanced multi-component rare earth oxide doped zirconia- yttria systems. The size of the oxide defect clusters and the cluster dopant segregation was typically ranging from 5 to 50 nm. These multi-component dopant induced defect clusters are an important factor for the coating long-term high temperature stability and excellent performance.

  18. Defect Clustering and Nano-Phase Structure Characterization of Multi-Component Rare Earth Oxide Doped Zirconia-Yttria Thermal Barrier Coatings

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming; Chen, Yuan L.; Miller, Robert A.

    1990-01-01

    Advanced oxide thermal barrier coatings have been developed by incorporating multi- component rare earth oxide dopants into zirconia-yttria to effectively promote the creation of the thermodynamically stable, immobile oxide defect clusters and/or nano-scale phases within the coating systems. The presence of these nano-sized defect clusters has found to significantly reduce the coating intrinsic thermal conductivity, improve sintering resistance, and maintain long-term high temperature stability. In this paper, the defect clusters and nano-structured phases, which were created by the addition of multi-component rare earth dopants to the plasma- sprayed and electron-beam physical vapor deposited thermal barrier coatings, were characterized by high-resolution transmission electron microscopy (TEM). The defect cluster size, distribution, crystallographic and compositional information were investigated using high-resolution TEM lattice imaging, selected area diffraction (SAD), and energy dispersive spectroscopy (EDS) analysis techniques. The results showed that substantial defect clusters were formed in the advanced multi-component rare earth oxide doped zirconia-yttria systems. The size of the oxide defect clusters and the cluster dopant segregation was typically ranging fiom 5 to 50 nm. These multi-component dopant induced defect clusters are an important factor for the coating long-term high temperature stability and excellent performance.

  19. Synthesis and properties of nanophase materials

    SciTech Connect

    Siegel, R.W.

    1993-03-01

    Nanophase materials, with their grain sizes or phase dimensions in the nanometer size regime, are now being produced by a wide variety of synthesis and processing methods. The interest in these new ultrafine-grained materials results primarily from the special nature of their various physical, chemical, and mechanical properties and the possibilities to control these properties during the synthesis and subsequent processing procedures. Since it is now becoming increasingly apparent that their properties can be engineered effectively during synthesis and processing, and that they can also be produced in quantity, nanophase materials should have considerable potential for technological development in a variety of applications. Some of the recent research on nanophase materials related to their synthesis and properties is briefly reviewed and the future potential of these new materials is considered.

  20. Crossed ferric oxide nanosheets supported cobalt oxide on 3-dimensional macroporous Ni foam substrate used for diesel soot elimination under self-capture contact mode

    NASA Astrophysics Data System (ADS)

    Cao, Chunmei; Li, Xingang; Zha, Yuqing; Zhang, Jing; Hu, Tiandou; Meng, Ming

    2016-03-01

    Crossed Fe2O3 nanosheets supported cobalt oxide nanoparticles on three-dimensionally macroporous nickel foam substrate (xCo/Fe-NF) was designed and successfully prepared through a facile hydrothermal and impregnation route. These catalysts showed high catalytic soot combustion activities under self-capture contact mode. The three-dimensional macroporous structures of Ni foam and the crossed Fe2O3 nanosheets constituted macroporous voids can greatly increase the contact efficiency between soot particulates and catalysts. The interaction between Co and Fe facilitated the activation of the Fe-O bond and increased the amounts of active oxygen species, thus improving the redox property of the catalysts. The 0.6Co/Fe-NF catalyst exhibited the highest turnover frequency (TOF) for soot combustion, which is in good accordance with the largest amount of active oxygen species. Based upon the catalytic performance and multiple characterization results, two reaction pathways for soot oxidation are identified, namely, the direct oxidation by the activated oxygen species via oxygen vacancies and the NOx-aided soot oxidation.Crossed Fe2O3 nanosheets supported cobalt oxide nanoparticles on three-dimensionally macroporous nickel foam substrate (xCo/Fe-NF) was designed and successfully prepared through a facile hydrothermal and impregnation route. These catalysts showed high catalytic soot combustion activities under self-capture contact mode. The three-dimensional macroporous structures of Ni foam and the crossed Fe2O3 nanosheets constituted macroporous voids can greatly increase the contact efficiency between soot particulates and catalysts. The interaction between Co and Fe facilitated the activation of the Fe-O bond and increased the amounts of active oxygen species, thus improving the redox property of the catalysts. The 0.6Co/Fe-NF catalyst exhibited the highest turnover frequency (TOF) for soot combustion, which is in good accordance with the largest amount of active oxygen species. Based upon the catalytic performance and multiple characterization results, two reaction pathways for soot oxidation are identified, namely, the direct oxidation by the activated oxygen species via oxygen vacancies and the NOx-aided soot oxidation. Electronic supplementary information (ESI) available: The images of HRTEM, EDS mapping, SEM, EXAFS and Fe 2p XPS. Table providing information on prepared catalysts. See DOI: 10.1039/c5nr05310b

  1. Nanophase change for data storage applications.

    PubMed

    Shi, L P; Chong, T C

    2007-01-01

    Phase change materials are widely used for date storage. The most widespread and important applications are rewritable optical disc and Phase Change Random Access Memory (PCRAM), which utilizes the light and electric induced phase change respectively. For decades, miniaturization has been the major driving force to increase the density. Now the working unit area of the current data storage media is in the order of nano-scale. On the nano-scale, extreme dimensional and nano-structural constraints and the large proportion of interfaces will cause the deviation of the phase change behavior from that of bulk. Hence an in-depth understanding of nanophase change and the related issues has become more and more important. Nanophase change can be defined as: phase change at the scale within nano range of 100 nm, which is size-dependent, interface-dominated and surrounding materials related. Nanophase change can be classified into two groups, thin film related and structure related. Film thickness and clapping materials are key factors for thin film type, while structure shape, size and surrounding materials are critical parameters for structure type. In this paper, the recent development of nanophase change is reviewed, including crystallization of small element at nano size, thickness dependence of crystallization, effect of clapping layer on the phase change of phase change thin film and so on. The applications of nanophase change technology on data storage is introduced, including optical recording such as super lattice like optical disc, initialization free disc, near field, super-RENS, dual layer, multi level, probe storage, and PCRAM including, superlattice-like structure, side edge structure, and line type structure. Future key research issues of nanophase change are also discussed. PMID:17455476

  2. Crossed ferric oxide nanosheets supported cobalt oxide on 3-dimensional macroporous Ni foam substrate used for diesel soot elimination under self-capture contact mode.

    PubMed

    Cao, Chunmei; Li, Xingang; Zha, Yuqing; Zhang, Jing; Hu, Tiandou; Meng, Ming

    2016-03-21

    Crossed Fe2O3 nanosheets supported cobalt oxide nanoparticles on three-dimensionally macroporous nickel foam substrate (xCo/Fe-NF) was designed and successfully prepared through a facile hydrothermal and impregnation route. These catalysts showed high catalytic soot combustion activities under self-capture contact mode. The three-dimensional macroporous structures of Ni foam and the crossed Fe2O3 nanosheets constituted macroporous voids can greatly increase the contact efficiency between soot particulates and catalysts. The interaction between Co and Fe facilitated the activation of the Fe-O bond and increased the amounts of active oxygen species, thus improving the redox property of the catalysts. The 0.6Co/Fe-NF catalyst exhibited the highest turnover frequency (TOF) for soot combustion, which is in good accordance with the largest amount of active oxygen species. Based upon the catalytic performance and multiple characterization results, two reaction pathways for soot oxidation are identified, namely, the direct oxidation by the activated oxygen species via oxygen vacancies and the NOx-aided soot oxidation. PMID:26509240

  3. Adhesion of Pseudomonas fluorescens onto nanophase materials

    NASA Astrophysics Data System (ADS)

    Webster, Thomas J.; Tong, Zonghua; Liu, Jin; Banks, M. Katherine

    2005-07-01

    Nanobiotechnology is a growing area of research, primarily due to the potentially numerous applications of new synthetic nanomaterials in engineering/science. Although various definitions have been given for the word 'nanomaterials' by many different experts, the commonly accepted one refers to nanomaterials as those materials which possess grains, particles, fibres, or other constituent components that have one dimension specifically less than 100 nm. In biological applications, most of the research to date has focused on the interactions between mammalian cells and synthetic nanophase surfaces for the creation of better tissue engineering materials. Although mammalian cells have shown a definite positive response to nanophase materials, information on bacterial interactions with nanophase materials remains elusive. For this reason, this study was designed to assess the adhesion of Pseudomonas fluorescens on nanophase compared to conventional grain size alumina substrates. Results provide the first evidence of increased adhesion of Pseudomonas fluorescens on alumina with nanometre compared to conventional grain sizes. To understand more about the process, polymer (specifically, poly-lactic-co-glycolic acid or PLGA) casts were made of the conventional and nanostructured alumina surfaces. Results showed similar increased Pseudomonas fluorescens capture on PLGA casts of nanostructured compared to conventional alumina as on the alumina itself. For these reasons, a key material property shown to enhance bacterial adhesion was elucidated in this study for both polymers and ceramics: nanostructured surface features.

  4. Environmental magnetism of nanophase iron minerals: Testing the biomineralization pathway

    NASA Astrophysics Data System (ADS)

    Banerjee, Subir K.

    2006-03-01

    Nanoparticles of iron oxides and iron oxyhydroxides are sensitive proxies of environmental change near the earth's surface. Our research programme aims to provide information about the environmental control variables (temperature, rainfall, pH, as well as microbial type and concentration) for the process of Fe(III) to Fe(II) reduction and solid phase precipitation. Such solid phases of environmental change proxies (e.g., magnetite and maghemite) are being produced in the laboratory for calibration of field data. Low temperature magnetometry and Mssbauer spectra are shown to be extremely useful for characterization and granulometry of such nanophases. In addition, it appears that magnetism may also be a sensitive probe for physical-chemical properties of the outermost 'skins' of such nanoparticles, confirming Louis Nel's predictions for the magnetic behavior of such outermost layers.

  5. Development of Surface Complexation Models of Cr(VI) Adsorption on Soils, Sediments and Model Mixtures of Kaolinite, Montmorillonite, γ-Alumina, Hydrous Manganese and Ferric Oxides and Goethite

    SciTech Connect

    Koretsky, Carla

    2013-11-29

    Hexavalent chromium is a highly toxic contaminant that has been introduced into aquifers and shallow sediments and soils via many anthropogenic activities. Hexavalent chromium contamination is a problem or potential problem in the shallow subsurface at several DOE sites, including Hanford, Idaho National Laboratory, Los Alamos National Laboratory and the Oak Ridge Reservation (DOE, 2008). To accurately quantify the fate and transport of hexavalent chromium at DOE and other contaminated sites, robust geochemical models, capable of correctly predicting changes in chromium chemical form resulting from chemical reactions occurring in subsurface environments are needed. One important chemical reaction that may greatly impact the bioavailability and mobility of hexavalent chromium in the subsurface is chemical binding to the surfaces of particulates, termed adsorption or surface complexation. Quantitative thermodynamic surface complexation models have been derived that can correctly calculate hexavalent chromium adsorption on well-characterized materials over ranges in subsurface conditions, such pH and salinity. However, models have not yet been developed for hexavalent chromium adsorption on many important constituents of natural soils and sediments, such as clay minerals. Furthermore, most of the existing thermodynamic models have been developed for relatively simple, single solid systems and have rarely been tested for the complex mixtures of solids present in real sediments and soils. In this study, the adsorption of hexavalent chromium was measured as a function of pH (3-10), salinity (0.001 to 0.1 M NaNO3), and partial pressure of carbon dioxide(0-5%) on a suite of naturally-occurring solids including goethite (FeOOH), hydrous manganese oxide (MnOOH), hydrous ferric oxide (Fe(OH)3), γ-alumina (Al2O3), kaolinite (Al2Si2O5(OH)4), and montmorillonite (Na3(Al, Mg)2Si4O10(OH)2�nH2O). The results show that all of these materials can bind substantial quantities of hexavalent chromium, especially at low pH. Unexpectedly, experiments with the clay minerals kaolinite and montmorillonite suggest that hexavalent chromium may interact with these solids over much longer periods of time than expected. Furthermore, hexavalent chromium may irreversibly bind to these solids, perhaps because of oxidation-reduction reactions occurring on the surfaces of the clay minerals. More work should be done to investigate and quantify these chemical reactions. Experiments conducted with mixtures of goethite, hydrous manganese oxide, hydrous ferric oxide, γ-alumina, montmorillonite and kaolinite demonstrate that it is possible to correctly predict hexavalent chromium binding in the presence of multiple minerals using thermodynamic models derived for the simpler systems. Further, these models suggest that of the six solid considered in this study, goethite is typically the solid to which most of the hexavalent chromium will bind. Experiments completed with organic-rich and organic-poor natural sediments demonstrate that in organic-rich substrates, organic matter is likely to control uptake of the hexavalent chromium. The models derived and tested in this study for hexavalent chromium binding to γ-alumina, hydrous manganese oxide, goethite, hydrous ferric oxide and clay minerals can be used to better predict changes in hexavalent chromium bioavailability and mobility in contaminated sediments and soils.

  6. 21 CFR 73.1299 - Ferric ferrocyanide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs 73.1299 Ferric ferrocyanide. (a) Identity. (1) The color additive ferric ferrocyanide is a ferric hexacyanoferrate pigment characterized by the structual... ferrocyanide. (2) Color additive mixtures for drug use made with ferric ferrocyanide may contain only...

  7. 21 CFR 73.1299 - Ferric ferrocyanide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs 73.1299 Ferric ferrocyanide. (a) Identity. (1) The color additive ferric ferrocyanide is a ferric hexacyanoferrate pigment characterized by the structual... ferrocyanide. (2) Color additive mixtures for drug use made with ferric ferrocyanide may contain only...

  8. 21 CFR 184.1297 - Ferric chloride.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Ferric chloride. 184.1297 Section 184.1297 Food... Specific Substances Affirmed as GRAS 184.1297 Ferric chloride. (a) Ferric chloride (iron (III) chloride... hydrogen chloride. The pure material occurs as hydroscopic, hexagonal, dark crystals. Ferric...

  9. 21 CFR 184.1297 - Ferric chloride.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Ferric chloride. 184.1297 Section 184.1297 Food... Specific Substances Affirmed as GRAS 184.1297 Ferric chloride. (a) Ferric chloride (iron (III) chloride... hydrogen chloride. The pure material occurs as hydroscopic, hexagonal, dark crystals. Ferric...

  10. 21 CFR 184.1297 - Ferric chloride.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Ferric chloride. 184.1297 Section 184.1297 Food... Specific Substances Affirmed as GRAS 184.1297 Ferric chloride. (a) Ferric chloride (iron (III) chloride... hydrogen chloride. The pure material occurs as hydroscopic, hexagonal, dark crystals. Ferric...

  11. Functionally Graded Nanophase Beryllium/Carbon Composites

    NASA Technical Reports Server (NTRS)

    Choi, Michael K.

    2003-01-01

    Beryllium, beryllium alloys, beryllium carbide, and carbon are the ingredients of a class of nanophase Be/Be2C/C composite materials that can be formulated and functionally graded to suit a variety of applications. In a typical case, such a composite consists of a first layer of either pure beryllium or a beryllium alloy, a second layer of B2C, and a third layer of nanophase sintered carbon derived from fullerenes and nanotubes. The three layers are interconnected through interpenetrating spongelike structures. These Be/Be2C/C composite materials are similar to Co/WC/diamond functionally graded composite materials, except that (1) W and Co are replaced by Be and alloys thereof and (2) diamond is replaced by sintered carbon derived from fullerenes and nanotubes. (Optionally, one could form a Be/Be2C/diamond composite.) Because Be is lighter than W and Co, the present Be/Be2C/C composites weigh less than do the corresponding Co/WC/diamond composites. The nanophase carbon is almost as hard as diamond. WC/Co is the toughest material. It is widely used for drilling, digging, and machining. However, the fact that W is a heavy element (that is, has high atomic mass and mass density) makes W unattractive for applications in which weight is a severe disadvantage. Be is the lightest tough element, but its toughness is less than that of WC/Co alloy. Be strengthened by nanophase carbon is much tougher than pure or alloy Be. The nanophase carbon has an unsurpassed strength-to-weight ratio. The Be/Be2C/C composite materials are especially attractive for terrestrial and aerospace applications in which there are requirements for light weight along with the high strength and toughness of the denser Co/WC/diamond materials. These materials could be incorporated into diverse components, including cutting tools, bearings, rocket nozzles, and shields. Moreover, because Be and C are effective as neutron moderators, Be/Be2C/C composites could be attractive for some nuclear applications.

  12. Coordination modes of tyrosinate-ligated catalase-type heme enzymes: magnetic circular dichroism studies of Plexaura homomalla allene oxide synthase, Mycobacterium avium ssp. paratuberculosis protein-2744c, and bovine liver catalase in their ferric and ferrous states.

    PubMed

    Bandara, D M Indika; Sono, Masanori; Bruce, Grant S; Brash, Alan R; Dawson, John H

    2011-12-01

    Bovine liver catalase (BLC), catalase-related allene oxide synthase (cAOS) from Plexaura homomalla, and a recently isolated protein from the cattle pathogen Mycobacterium avium ssp. paratuberculosis (MAP-2744c (MAP)) are all tyrosinate-ligated heme enzymes whose crystal structures have been reported. cAOS and MAP have low (<20%) sequence similarity to, and significantly different catalytic functions from, BLC. cAOS transforms 8R-hydroperoxy-eicosatetraenoic acid to an allene epoxide, whereas the MAP protein is a putative organic peroxide-dependent peroxidase. To elucidate factors influencing the functions of these and related heme proteins, we have investigated the heme iron coordination properties of these tyrosinate-ligated heme enzymes in their ferric and ferrous states using magnetic circular dichroism and UV-visible absorption spectroscopy. The MAP protein shows remarkable spectral similarities to cAOS and BLC in its native Fe(III) state, but clear differences from ferric proximal heme ligand His93Tyr Mb (myoglobin) mutant, which may be attributed to the presence of an Arg(+)-N(?)-HO-Tyr (proximal heme axial ligand) hydrogen bond in the first three heme proteins. Furthermore, the spectra of Fe(III)-CN, Fe(III)-NO, Fe(II)-NO (except for five-coordinate MAP), Fe(II)-CO, and Fe(II)-O(2) states of cAOS and MAP, but not H93Y Mb, are also similar to the corresponding six-coordinate complexes of BLC, suggesting that a tyrosinate (Tyr-O) is the heme axial ligand trans to the bound ligands in these complexes. The Arg(+)-N(?)-H to O-Tyr hydrogen bond would be expected to modulate the donor properties of the proximal tyrosinate oxyanion and, combined with the subtle differences in the catalytic site structures, affect the activities of cAOS, MAP and BLC. PMID:22104301

  13. Reflectance spectroscopy of ferric sulfate-bearing montmorillonites as Mars soil analog materials

    NASA Technical Reports Server (NTRS)

    Bishop, J. L.; Pieters, C. M.; Burns, R. G.; Edwards, J. O.; Mancinelli, R. L.; Froschl, H.

    1995-01-01

    Spectroscopic analyses have shown that smectites enhanced in the laboratory with additional ferric species exhibit important similarities to those of the soils on Mars. Ferrihydrite in these chemically treated smectites has features in the visible to near-infrared region that resemble the energies and band strengths of features in reflectance spectra observed for several bright regions on Mars. New samples have been prepared with sulfate as well, because S was found by Viking to be a major component in the surface material on Mars. A suite of ferrihydrite-bearing and ferric sulfate-bearing montmorillonites, prepared with variable Fe3+ and S concentrations and variable pH conditions, has been analyzed using reflectance spectroscopy in the visible and infrared regions, Mossbauer spectroscopy at room temperature and 4 K, differential thermal analysis, and X-ray diffraction. These analyses support the formation of ferrihydrite of variable crystallinity in the ferrihydrite-bearing montmorillonites and a combination of schwertmannite and ferrihydrite in the ferric sulfate-bearing montmorillonites. Small quantities of poorly crystalline or nanophase forms of other ferric materials may also be present in these samples. The chemical formation conditions of the ferrihydrite-bearing and ferric sulfate-bearing montmorillonites influence the character of the low temperature Mossbauer sextets and the visible reflectance spectra. An absorption minimum is observed at 0.88-0.89 micrometers in spectra of the ferric sulfate-bearing samples, and at 0.89-0.92 micrometers in spectra of the ferrihydrate-bearing montmorillonites. Mossbauer spectra of the ferric sulfate-bearing montmorillonites indicate variable concentrations of ferrihydrite and schwertmannite in the interlaminar spaces and along grain surfaces. Dehydration under reduced atmospheric pressure conditions induces a greater effect on the adsorbed and interlayer water in ferrihydrite-bearing montmorillonite than on the water in ferric sulfate-bearing montmorillonite. Reflectance spectra of ferric sulfate-bearing montmorillonite include a strong 3-micrometers band that is more resistant to dry atmospheric conditions than the 3-micrometers band in spectra of similarly prepared ferrihydrite-bearing montmorillonites.

  14. Reflectance spectroscopy of ferric sulfate-bearing montmorillonites as Mars soil analog materials.

    PubMed

    Bishop, J L; Pieters, C M; Burns, R G; Edwards, J O; Mancinelli, R L; Frschl, H

    1995-09-01

    Spectroscopic analyses have shown that smectites enhanced in the laboratory with additional ferric species exhibit important similarities to those of the soils on Mars. Ferrihydrite in these chemically treated smectites has features in the visible to near-infrared region that resemble the energies and band strengths of features in reflectance spectra observed for several bright regions on Mars. New samples have been prepared with sulfate as well, because S was found by Viking to be a major component in the surface material on Mars. A suite of ferrihydrite-bearing and ferric sulfate-bearing montmorillonites, prepared with variable Fe3+ and S concentrations and variable pH conditions, has been analyzed using reflectance spectroscopy in the visible and infrared regions, Mssbauer spectroscopy at room temperature and 4 K, differential thermal analysis, and X-ray diffraction. These analyses support the formation of ferrihydrite of variable crystallinity in the ferrihydrite-bearing montmorillonites and a combination of schwertmannite and ferrihydrite in the ferric sulfate-bearing montmorillonites. Small quantities of poorly crystalline or nanophase forms of other ferric materials may also be present in these samples. The chemical formation conditions of the ferrihydrite-bearing and ferric sulfate-bearing montmorillonites influence the character of the low temperature Mssbauer sextets and the visible reflectance spectra. An absorption minimum is observed at 0.88-0.89 micrometers in spectra of the ferric sulfate-bearing samples, and at 0.89-0.92 micrometers in spectra of the ferrihydrate-bearing montmorillonites. Mssbauer spectra of the ferric sulfate-bearing montmorillonites indicate variable concentrations of ferrihydrite and schwertmannite in the interlaminar spaces and along grain surfaces. Dehydration under reduced atmospheric pressure conditions induces a greater effect on the adsorbed and interlayer water in ferrihydrite-bearing montmorillonite than on the water in ferric sulfate-bearing montmorillonite. Reflectance spectra of ferric sulfate-bearing montmorillonite include a strong 3-micrometers band that is more resistant to dry atmospheric conditions than the 3-micrometers band in spectra of similarly prepared ferrihydrite-bearing montmorillonites. PMID:11538594

  15. ESTCP DEMONSTRATION OF A BIOAVAILABLE FERRIC IRON TEST KIT

    EPA Science Inventory

    Bioavailable ferric iron (BAFeIII) is used by iron-reducing bacteria as an electron acceptor during the oxidation of various organic contaminants such as vinyl chloride and benzene. Quantification of BAFeIII is important with respect to characterizing candidate natural attenuati...

  16. DEMONSTRATION OF A BIOAVAILABLE FERRIC IRON TEST KIT

    EPA Science Inventory

    Bioavailable ferric iron (BAFeIII) is used by iron-reducing bacteria as an electron acceptor during the oxidation of various organic contaminants such as vinyl chloride and benzene. Quantification of BAFeIII is important with respect to characterizing candidate natural attenuati...

  17. 21 CFR 582.5304 - Ferric pyrophosphate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 582.5304 Ferric pyrophosphate. (a) Product. Ferric pyrophosphate. (b) Conditions of use....

  18. 21 CFR 582.5304 - Ferric pyrophosphate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 582.5304 Ferric pyrophosphate. (a) Product. Ferric pyrophosphate. (b) Conditions of use....

  19. 21 CFR 582.5304 - Ferric pyrophosphate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 582.5304 Ferric pyrophosphate. (a) Product. Ferric pyrophosphate. (b) Conditions of use....

  20. Detecting Nanophase Weathering Products with CheMin: Reference Intensity Ratios of Allophane, Aluminosilicate Gel, and Ferrihydrite

    NASA Technical Reports Server (NTRS)

    Rampe, E. B.; Bish, D. L.; Chipera, S. J.; Morris, R. V.; Achilles, C. N.; Ming, D W.; Blake, D. F.; Anderson, R. C.; Bristow, T. F.; Crisp, A.; DesMarais, D. J.; Downs, R. T.; Farmer, J. D.; Morookian, J. M.; Morrison, S. M.; Sarrazin, P.; Spanovich, N.; Stolper, E. M.; Treiman, A. H.; Vaniman, D. T.; Yen, A. S.

    2013-01-01

    X-ray diffraction (XRD) data collected of the Rocknest samples by the CheMin instrument on Mars Science Laboratory suggest the presence of poorly crystalline or amorphous materials [1], such as nanophase weathering products or volcanic and impact glasses. The identification of the type(s) of X-ray amorphous material at Rocknest is important because it can elucidate past aqueous weathering processes. The presence of volcanic and impact glasses would indicate that little chemical weathering has occurred because glass is highly susceptible to aqueous alteration. The presence of nanophase weathering products, such as allophane, nanophase iron-oxides, and/or palagonite, would indicate incipient chemical weathering. Furthermore, the types of weathering products present could help constrain pH conditions and identify which primary phases altered to form the weathering products. Quantitative analysis of phases from CheMin data is achieved through Reference Intensity Ratios (RIRs) and Rietveld refinement. The RIR of a mineral (or mineraloid) that relates the scattering power of that mineral (typically the most intense diffraction line) to the scattering power of a separate mineral standard such as corundum [2]. RIRs can be calculated from XRD patterns measured in the laboratory by mixing a mineral with a standard in known abundances and comparing diffraction line intensities of the mineral to the standard. X-ray amorphous phases (e.g., nanophase weathering products) have broad scattering signatures rather than sharp diffraction lines. Thus, RIRs of X-ray amorphous materials are calculated by comparing the area under one of these broad scattering signals with the area under a diffraction line in the standard. Here, we measured XRD patterns of nanophase weathering products (allophane, aluminosilicate gel, and ferrihydrite) mixed with a mineral standard (beryl) in the CheMinIV laboratory instrument and calculated their RIRs to help constrain the abundances of these phases in the Rocknest samples.

  1. 21 CFR 582.5301 - Ferric phosphate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Ferric phosphate. 582.5301 Section 582.5301 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Supplements 1 § 582.5301 Ferric phosphate. (a) Product. Ferric phosphate. (b) Conditions of use....

  2. 21 CFR 582.5301 - Ferric phosphate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Ferric phosphate. 582.5301 Section 582.5301 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Supplements 1 § 582.5301 Ferric phosphate. (a) Product. Ferric phosphate. (b) Conditions of use....

  3. 21 CFR 582.5301 - Ferric phosphate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Ferric phosphate. 582.5301 Section 582.5301 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Supplements 1 § 582.5301 Ferric phosphate. (a) Product. Ferric phosphate. (b) Conditions of use....

  4. 21 CFR 582.5301 - Ferric phosphate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Ferric phosphate. 582.5301 Section 582.5301 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Supplements 1 § 582.5301 Ferric phosphate. (a) Product. Ferric phosphate. (b) Conditions of use....

  5. 21 CFR 582.5301 - Ferric phosphate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Ferric phosphate. 582.5301 Section 582.5301 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Supplements 1 § 582.5301 Ferric phosphate. (a) Product. Ferric phosphate. (b) Conditions of use....

  6. 21 CFR 73.1299 - Ferric ferrocyanide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... color additive ferric ferrocyanide is a ferric hexacyanoferrate pigment characterized by the structual... ferrocyanide. (2) Color additive mixtures for drug use made with ferric ferrocyanide may contain only those diluents listed in this subpart as safe and suitable for use in color additive mixtures for coloring...

  7. Is superplasticity in the future of nanophase materials

    SciTech Connect

    Siegel, R.W.

    1990-07-01

    The ultrafine grain sizes and high diffusivities in nanophase materials assembled from atomic clusters suggest that these materials may have a strong tendency toward superplastic mechanical behavior. Both small grain size and enhanced diffusivity can be expected to lead to increased diffusional creep rates as well as to a significantly greater propensity for grain boundary sliding. Recent mechanical properties measurements at room temperature on nanophase Cu, Pd, and TiO{sub 2}, however, give no indications of superplasticity. Nonetheless, significant ductility has been clearly demonstrated in these studies of both nanophase ceramics and metals. The synthesis of cluster-assembled nanophase materials is described and the salient features of what is known of their structure and mechanical properties is reviewed. Finally, the answer to the question posed in the title is addressed. 34 refs., 6 figs.

  8. Superhard nanophase materials for rock drilling applications

    SciTech Connect

    Sadangi, R.K.; Voronov, O.A.; Tompa, G.S.; Kear, B.H.

    1997-12-31

    Diamond Materials Incorporated is developing new class of superhard materials for rock drilling applications. In this paper, we will describe two types of superhard materials, (a) binderless polycrystalline diamond compacts (BPCD), and (b) functionally graded triphasic nanocomposite materials (FGTNC). BPCDs are true polycrystalline diamond ceramic with < 0.5 wt% binders and have demonstrated to maintain their wear properties in a granite-log test even after 700{degrees}C thermal treatment. FGTNCs are functionally-graded triphasic superhard material, comprising a nanophase WC/Co core and a diamond-enriched surface, that combine high strength and toughness with superior wear resistance, making FGTNC an attractive material for use as roller cone stud inserts.

  9. Transparent monolithic metal ion containing nanophase aerogels

    SciTech Connect

    Risen, W. M., Jr.; Hu, X.; Ji, S.; Littrell, K.

    1999-12-01

    The formation of monolithic and transparent transition metal containing aerogels has been achieved through cooperative interactions of high molecular weight functionalized carbohydrates and silica precursors, which strongly influence the kinetics of gelation. After initial gelation, subsequent modification of the ligating character of the system, coordination of the group VIII metal ions, and supercritical extraction afford the aerogels. The structures at the nanophase level have been probed by photon and electron transmission and neutron scattering techniques to help elucidate the basis for structural integrity together with the small entity sizes that permit transparency in the visible range. They also help with understanding the chemical reactivities of the metal-containing sites in these very high surface area materials. These results are discussed in connection with new reaction studies.

  10. Hydrogen Storage in Nano-Phase Diamond at High Temperature and Its Release

    SciTech Connect

    Tushar K Ghosh

    2008-10-13

    The objectives of this proposed research were: 91) Separation and storage of hydrogen on nanophase diamonds. It is expected that the produced hydrogen, which will be in a mixture, can be directed to a nanophase diamond system directly, which will not only store the hydrogen, but also separate it from the gas mixture, and (2) release of the stored hydrogen from the nanophase diamond.

  11. Hydrogen Reduction of Ferric Ions for Use in Copper Electrowinning

    SciTech Connect

    Karl S. Noah; Debby F. Bruhn; John E. Wey; Robert S. Cherry

    2005-01-01

    The conventional copper electrowinning process uses the water hydrolysis reaction as the anodic source of electrons. However this reaction generates acid mist and requires large quantities of energy. In order to improve energy efficiency and avoid acid mist, an alternative anodic reaction of ferrous ion oxidation has been proposed. This reaction does not involve evolution of acid mist and can be carried out at a lower cell voltage than the conventional process. However, because ferrous ions are converted to ferric ions at the anode in this process, there is a need for reduction of ferric ions to ferrous ions to continue this process. The most promising method for this reduction is the use of hydrogen gas since the resulting byproduct acid can be used elsewhere in the process and, unlike other reductants, hydrogen does not introduce other species that need subsequent removal. Because the hydrogen reduction technology has undergone only preliminary lab scale testing, additional research is needed to evaluate its commercial potential. Two issues for this research are the potentially low mass transfer rate of hydrogen into the electrolyte stream because of its low solubility in water, and whether other gaseous reductants less expensive than hydrogen, such as natural gas or syngas, might work. In this study various reductants were investigated to carry out the reduction of ferric ions to ferrous ions using a simulated electrolyte solution recycled through a trickle bed reactor packed with catalyst. The gases tested as reductants were hydrogen, methane, carbon monoxide, and a 50/50 mixture of H2 and CO. Nitrogen was also tested as an inert control. These gases were tested because they are constituents in either natural gas or syngas. The catalysts tested were palladium and platinum. Two gas flow rates and five electrolyte flow rates were tested. Pure hydrogen was an effective reductant of ferric ion. The rates were similar with both palladium and platinum. The ferric iron reduction increased with both the flow rate of gas as well as the liquid flow rate (up to ~0.1 g/L/min). Pure carbon monoxide also reduced the ferric ion, but at a rate about one tenth that of pure hydrogen at similar conditions. The syngas mixture of equimolar hydrogen and carbon monoxide reacted at a rate intermediate between each gas as a pure stream (up to ~ 0.06 g/L/min). This gas mixture shows that some form of unpurified reformer gas could be used to reduce the ferric ion in the electrolyte solution. Nitrogen was inert causing very little to no reduction of ferric ion.

  12. The role of hydrous ferric oxide precipitation in the fractionation of arsenic, gallium, and indium during the neutralization of acidic hot spring water by river water in the Tama River watershed, Japan

    NASA Astrophysics Data System (ADS)

    Ogawa, Yasumasa; Ishiyama, Daizo; Shikazono, Naotatsu; Iwane, Kenta; Kajiwara, Masahiro; Tsuchiya, Noriyoshi

    2012-06-01

    The Obuki spring is the largest and most acidic of the Tamagawa hot springs (Akita Prefecture, northern Japan), and it discharges ca. 9000 L/min of chloride-rich acidic water (pH 1.2) that contains high concentrations of both As and rare metals such as Ga and In. This paper aims to quantify seasonal variations in the mobility of these elements in the Shibukuro and Tama rivers, which are fed by the thermal waters of the Obuki spring, caused by sorption onto hydrous ferric oxide (HFO). Seasonal observations revealed the following relationships with respect to As removal by HFO: (a) the oxidation of Fe2+ is predominantly controlled by both pH and water temperature, and progresses more quickly in less acidic and warmer conditions; (b) HFO formation was predominantly controlled by pH; and (c) the removal of dissolved arsenate is directly related to the amount of HFO present. Consequently, the oxidation to Fe3+ was slower during periods of cold and lower pH, and the amount of HFO was too small to remove the dissolved arsenate effectively. Consequently, considerable amounts of dissolved arsenate and Fe2+ remained in river water. In contrast, when HFO production from Fe3+ increased, and dissolved arsenate was removed during warmer and less acidic periods, only small amounts of dissolved arsenite and Fe2+ remained in the river water. The geochemical behavior of Ga and In was essentially controlled by pH; however, when HFO production was limited by a pH of less than 3.5, Ga behavior was controlled mainly by the amount of HFO. Gallium tended to be sorbed under more acidic conditions than was In. Due to differences in sorption behavior, Ga, As, and In were fractionated during sedimentation. In the upstream reaches, arsenate and dissolved Ga sorbed onto HFO, and were widely distributed across the watershed. Conversely, dissolved In was removed by HFO downstream. As a result, In is relatively concentrated on the downstream lakebed, unlike As and Ga, and In-rich mineral deposits are accumulating at present.

  13. Access of ligands to the ferric center in lipoxygenase-1.

    PubMed

    Gaffney, B J; Mavrophilipos, D V; Doctor, K S

    1993-03-01

    A form of ferric lipoxygenase-1 has been isolated that gives an EPR spectrum that is dominated by a species of intermediate rhombicity (E/D = 0.065). This species is obtained in the presence of a number of buffers of high concentration and in the absence of fatty acid byproducts of the iron oxidation. The species is unstable over a period of one day with respect to symmetry of the iron. The EPR lineshapes of the unstable species are highly sensitive to the anionic composition of the buffer and to the addition of neutral ligands. These results suggest that newly formed ferric lipoxygenase has weak affinity for a number of ligands. Affinity of charged ligands for the iron center may provide a mechanism for charge compensation as the iron center alternates between ferric and ferrous in the catalytic cycle. We use spectral simulation to evaluate quantitatively the interaction of the ferric center with ligands and also show that a transition in the middle Kramers doublet makes a significant contribution to the EPR spectrum of the more rhombic species. PMID:8386016

  14. Superhard nanophase cutter materials for rock drilling applications

    SciTech Connect

    Voronov, O.; Tompa, G.; Sadangi, R.; Kear, B.; Wilson, C.; Yan, P.

    2000-06-23

    The Low Pressure-High Temperature (LPHT) System has been developed for sintering of nanophase cutter and anvil materials. Microstructured and nanostructured cutters were sintered and studied for rock drilling applications. The WC/Co anvils were sintered and used for development of High Pressure-High Temperature (HPHT) Systems. Binderless diamond and superhard nanophase cutter materials were manufactured with help of HPHT Systems. The diamond materials were studied for rock machining and drilling applications. Binderless Polycrystalline Diamonds (BPCD) have high thermal stability and can be used in geothermal drilling of hard rock formations. Nanophase Polycrystalline Diamonds (NPCD) are under study in precision machining of optical lenses. Triphasic Diamond/Carbide/Metal Composites (TDCC) will be commercialized in drilling and machining applications.

  15. Raman Mapping for the Investigation of Nano-phased Materials

    NASA Astrophysics Data System (ADS)

    Gouadec, G.; Bellot-Gurlet, L.; Baron, D.; Colomban, Ph.

    Nanosized and nanophased materials exhibit special properties. First they offer a good compromise between the high density of chemical bonds by unit volume, needed for good mechanical properties and the homogeneity of amorphous materials that prevents crack initiation. Second, interfaces are in very high concentration and they have a strong influence on many electrical and redox properties. The analysis of nanophased, low crystallinity materials is not straigtforward. The recording of Raman spectra with a geometric resolution close to 0.5 \\upmu {text{ m}^3} and the deep understanding of the Raman signature allow to locate the different nanophases and to predict the properties of the material. Case studies are discussed: advanced polymer fibres, ceramic fibres and composites, textured piezoelectric ceramics and corroded (ancient) steel.

  16. Method of treating inflammatory diseases using a radiolabeled ferric hydroxide calloid

    DOEpatents

    Atcher, Robert W.; Hines, John J.

    1992-01-01

    A ferric hydroxide colloid having an alpha-emitting radionuclide essentially on the outer surfaces and a method of forming same. The method includes oxidizing a ferrous hydroxide to ferric hydroxide in the presence of a preselected radionuclide to form a colloid having the radionuclide on the outer surface thereof, and thereafter washing the colloid, and suspending the washed colloid in a suitable solution. The labelled colloid is useful in cancer therapy and for the treatment of inflamed joints.

  17. Structure and properties of nanophase TiO/sub 2/

    SciTech Connect

    Siegel, R.W.; Hahn, H.; Ramasamy, S.; Zongquan, Li; Ting, Lu; Gronsky, R.

    1987-07-01

    Ultrafine-grained, nanophase samples of TiO/sub 2/ (rutile) were synthesized by the gas-condensation method and subsequent in-situ compaction, and then studied by transmission electron microscopy, Vickers hardness measurements, and positron annihilation spectroscopy as a function of sintering temperature. The nanophase compacts densified rapidly above 500/sup 0/C, with only a small increase in grain size. The hardness values obtained by this method are comparable to or greater than coarser-grained compacts, but at temperatures 400 to 600/sup 0/C lower than conventional sintering temperatures and without the need for sintering aids. 11 refs., 3 figs.

  18. 21 CFR 184.1301 - Ferric phosphate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Ferric phosphate. 184.1301 Section 184.1301 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 § 184.1301 Ferric phosphate. (a)...

  19. 21 CFR 582.5304 - Ferric pyrophosphate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Ferric pyrophosphate. 582.5304 Section 582.5304 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 1 582.5304 Ferric pyrophosphate....

  20. Ferric sulfate montmorillonites as Mars soil analogs

    NASA Technical Reports Server (NTRS)

    Bishop, J. L.; Pieters, C. M.; Burns, R. G.

    1993-01-01

    Spectroscopic analyses have shown that Fe(3+)-doped smectites prepared in the laboratory exhibit important similarities to the soils on Mars. Ferrihydrite in these smectites has features in the visible to near-infrared region that resemble the energies and band-strengths of features in reflectance spectra observed for several bright regions on Mars. Ferric - sulfate - montmorillonite samples have been prepared more recently because they are a good compositional match with the surface material on Mars as measured by Viking. Reflectance spectra of montmorillonite doped with ferric sulfate in the interlayer regions include a strong 3 micron band that persists under dry conditions. This is in contrast to spectra of similarly prepared ferric-doped montmorillonites, which exhibit a relatively weaker 3 micron band under comparable dry environmental conditions. Presented here are reflectance spectra of a suite of ferric-sulfate exchanged montmorillonites prepared with variable ferric sulfate concentrations and variable pH conditions.

  1. Hydrolysis of ferric chloride in solution

    SciTech Connect

    Lussiez, G.; Beckstead, L.

    1996-11-01

    The Detox{trademark} process uses concentrated ferric chloride and small amounts of catalysts to oxidize organic compounds. It is under consideration for oxidizing transuranic organic wastes. Although the solution is reused extensively, at some point it will reach the acceptable limit of radioactivity or maximum solubility of the radioisotopes. This solution could be cemented, but the volume would be increased substantially because of the poor compatibility of chlorides and cement. A process has been developed that recovers the chloride ions as HCl and either minimizes the volume of radioactive waste or permits recycling of the radioactive chlorides. The process involves a two-step hydrolysis at atmospheric pressure, or preferably under a slight vacuum, and relatively low temperature, about 200{degrees}C. During the first step of the process, hydrolysis occurs according to the reaction below: FeCl{sub 3 liquid} + H{sub 2}O {r_arrow} FeOCl{sub solid} + 2 HCl{sub gas} During the second step, the hot, solid, iron oxychloride is sprayed with water or placed in contact with steam, and hydrolysis proceeds to the iron oxide according to the following reaction: 2 FeOCl{sub solid} + H{sub 2}O {r_arrow} Fe{sub 2}O{sub 3 solid} + 2 HCl{sub gas}. The iron oxide, which contains radioisotopes, can then be disposed of by cementation or encapsulation. Alternately, these chlorides can be washed off of the solids and can then either be recycled or disposed of in some other way.

  2. Recovery of scrap iron metal value using biogenerated ferric iron.

    PubMed

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

    2006-04-20

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

  3. 21 CFR 184.1298 - Ferric citrate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Reg. No. 2338-05-8) is prepared from reaction of citric acid with ferric hydroxide. It is a compound of indefinite ratio of citric acid and iron. (b) The ingredient must be of a purity suitable for...

  4. 21 CFR 184.1298 - Ferric citrate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... Reg. No. 2338-05-8) is prepared from reaction of citric acid with ferric hydroxide. It is a compound of indefinite ratio of citric acid and iron. (b) The ingredient must be of a purity suitable for...

  5. 21 CFR 184.1298 - Ferric citrate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... Reg. No. 2338-05-8) is prepared from reaction of citric acid with ferric hydroxide. It is a compound of indefinite ratio of citric acid and iron. (b) The ingredient must be of a purity suitable for...

  6. 21 CFR 184.1298 - Ferric citrate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... prepared from reaction of citric acid with ferric hydroxide. It is a compound of indefinite ratio of citric acid and iron. (b) The ingredient must be of a purity suitable for its intended use. (c) In...

  7. 21 CFR 184.1298 - Ferric citrate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... Reg. No. 2338-05-8) is prepared from reaction of citric acid with ferric hydroxide. It is a compound of indefinite ratio of citric acid and iron. (b) The ingredient must be of a purity suitable for...

  8. 21 CFR 73.2299 - Ferric ferrocyanide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2299 Ferric ferrocyanide. (a) Identity and... coloring externally applied cosmetics, including cosmetics applied to the area of the eye, in...

  9. 21 CFR 73.2299 - Ferric ferrocyanide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2299 Ferric ferrocyanide. (a) Identity and... coloring externally applied cosmetics, including cosmetics applied to the area of the eye, in...

  10. 21 CFR 73.2299 - Ferric ferrocyanide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2299 Ferric ferrocyanide. (a) Identity and... coloring externally applied cosmetics, including cosmetics applied to the area of the eye, in...

  11. 21 CFR 73.2299 - Ferric ferrocyanide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2299 Ferric ferrocyanide. (a) Identity and... coloring externally applied cosmetics, including cosmetics applied to the area of the eye, in...

  12. 21 CFR 73.2299 - Ferric ferrocyanide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2299 Ferric ferrocyanide. (a) Identity and... coloring externally applied cosmetics, including cosmetics applied to the area of the eye, in...

  13. Hematite, pyroxene, and phyllosilicates on Mars: Implications from oxidized impact melt rocks from Manicouagan Crater, Quebec, Canada

    NASA Technical Reports Server (NTRS)

    Morris, Richard V.; Golden, D. C.; Bell, James F., III; Lauer, H. V., Jr.

    1995-01-01

    Visible and near-IR reflectivity, Mossbauer, and X ray diffraction data were obtained on powders of impact melt rock from the Manicouagan Impact Crater located in Quebec, Canada. The iron mineralogy is dominated by pyroxene for the least oxidized samples and by hematite for the most oxidized samples. Phyllosilicate (smectite) contents up to 15 wt % were found in some heavily oxidized samples. Nanophase hematite and/or paramagnetic ferric iron is observed in all samples. No hydrous ferric oxides (e.g., goethite, lepidocrocite, and ferrihydrite) were detected, which implies the alteration occurred above 250 C. Oxidative alteration is thought to have occurred predominantly during late-stage crystallization and subsolidus cooling of the impact melt by invasion of oxidizing vapors and/or solutions while the impact melt rocks were still hot. The near-IR band minimum correlated with the extent of aleration (Fe(3+)/Fe(sub tot)) and ranged from approx. 1000 nm (high-Ca pyroxene) to approx. 850 nm (bulk, well-crystalline hematite) for least and most oxidized samples, respectively. Intermediate band positions (900-920 nm) are attributed to low-Ca pyroxene and/or a composite band from hematite-pyroxene assemblages. Manicouagan data are consistent with previous assignments of hematite and pyroxene to the 850 and 1000 nm bands observed in Martian reflectivity spectra. Manicouagan data also show that possible assignments for intermediate band positions (900-920 nm) in Martian spectra are pyroxene and/or hematite-pyroxene assemblages. By analogy with impact melt sheets and in agreement with observables for Mars, oxidative alteration of Martian impact melt sheets above 250 C and subsequent erosion could produce rocks and soils with variable proportions of hematite (both bulk and nanophase), pyroxene, and phyllosilicates as iron-bearing mineralogies. If this process is dominant, these phases on Mars were formed rapidly at relatively high temperatures on a sporadic basis throughout the history of the planet. The Manicouagan samples also show that this mineralogical diversity can be accomplished at constant chemical composition, which is also indicated for Mars from analyses of soil at the two Viking landing sites.

  14. Hematite, pyroxene, and phyllosilicates on Mars: Implications from oxidized impact melt rocks from Manicouagan Crater, Quebec, Canada

    NASA Technical Reports Server (NTRS)

    Morris, Richard V.; Golden, D. C.; Bell, James F., III; Lauer, H. V., Jr.

    1995-01-01

    Visible and near-IR refectivity, Moessbauer, and X ray diffraction data were obtained on powders of impact melt rock from the Manicouagan Impact Crater located in Quebec, Canada. The iron mineralogy is dominated by pyroxene for the least oxidized samples and by hematite for the most oxidized samples. Phyllosilicate (smectite) contents up to approximately 15 wt % were found in some heavily oxidized samples. Nanophase hematite and/or paramagnetic ferric iron is observed in all samples. No hydrous ferric oxides (e.g., goethite, lepidocrocite, and ferrihydrite) were detected, which implies the alteration occurred above 250 C. Oxidative alteration is thought to have occurred predominantly during late-stage crystallization and subsolidus cooling of the impact melt by invasion of oxidizing vapors and/or solutions while the impact melt rocks were still hot. The near-IR band minimum correlated with the extent of aleration Fe(3+)/Fe(sub tot) and ranged from approximately 1000 nm (high-Ca pyroxene) to approximately 850 nm (bulk, well-crystalline hematite) for least and most oxidized samples, respectively. Intermediate band positions (900-920 nm) are attributed to low-Ca pyroxene and/or a composite band from hematite-pyroxene assemblages. Manicouagan data are consistent with previous assignments of hematite and pyroxene to the approximately 850 and approximately 1000nm bands observed in Martian reflectivity spectra. Manicouagan data also show that possible assignments for intermediate band positions (900-920 nm) in Martian spectra are pyroxene and/or hematite-pyroxene assemblages. By analogy with impact melt sheets and in agreement with observables for Mars, oxidative alteration of Martian impact melt sheets above 250 C and subsequent erosion could produce rocks and soils with variable proportions of hematite (both bulk and nanophase), pyroxene, and phyllosilicates as iron-bearing mineralogies. If this process is dominant, these phases on Mars were formed rapidly at relativly high temperatures on a sporadic basis throughout the history of the planet. The Manicouagan samples also show that this mineralogical diversity can be accomplished at constant chemical composition, which is also indicated for Mars from the analyses of soil at the two Viking landing sites.

  15. Nanophase Nickel-Zirconium Alloys for Fuel Cells

    NASA Technical Reports Server (NTRS)

    Narayanan, Sekharipuram; Whitacre, jay; Valdez, Thomas

    2008-01-01

    Nanophase nickel-zirconium alloys have been investigated for use as electrically conductive coatings and catalyst supports in fuel cells. Heretofore, noble metals have been used because they resist corrosion in the harsh, acidic fuel cell interior environments. However, the high cost of noble metals has prompted a search for less-costly substitutes. Nickel-zirconium alloys belong to a class of base metal alloys formed from transition elements of widely different d-electron configurations. These alloys generally exhibit unique physical, chemical, and metallurgical properties that can include corrosion resistance. Inasmuch as corrosion is accelerated by free-energy differences between bulk material and grain boundaries, it was conjectured that amorphous (glassy) and nanophase forms of these alloys could offer the desired corrosion resistance. For experiments to test the conjecture, thin alloy films containing various proportions of nickel and zirconium were deposited by magnetron and radiofrequency co-sputtering of nickel and zirconium. The results of x-ray diffraction studies of the deposited films suggested that the films had a nanophase and nearly amorphous character.

  16. Sinter-forging of nanophase TiO sub 2

    SciTech Connect

    Uchic, M.; Hofler, H.J.; Flick, W.J.; Tao, R.; Averback, R.S. . Dept. of Materials Science and Engineering); Kurath, P. . Dept. of Mechanical Engineering)

    1992-03-01

    Considerable effort has been directed in recent years to developing ceramic materials that can be both sintered to full density at low temperatures and processed by superplastic forming. One strategy for achieving this goal has been to reduce the particle size of the starting powder, and by anaphase processing, particles of sizes less than {approx}10 nm can now be realized. Indeed, recent studies on nanophase ceramics have demonstrated that sintering temperatures can be reduced dramatically and that nanophase ceramics have excellent potential for superplastic forming. Nevertheless, the grain growth that occurs during the processing of these new materials restricts their applicability. In nanophase (n-) TiO{sub 2}, some progress in controlling grain size has been achieved by using dopants or hot pressing. Sinter-forging offers another means to achieve this goal, although this method has been applied mostly to materials with larger grains. Studies of sinter-forging are also useful for elucidating the mechanisms of sintering and creep in ceramic materials. In the present paper, the authors examine the characteristics of sinter-forging in n-TiO{sub 2}. Only limited studies of sinter-forging have thus far been performed on well characterized powders of comparable size, and even these had a somewhat larger grain size.

  17. New nanophase iron-based catalysts for hydrocracking applications

    SciTech Connect

    Matson, D.W.; Linehan, J.C.; Darab, J.G.; Camaioni, D.M.; Autrey, S.T.; Lui, E.

    1994-11-01

    Development of highly efficient iron-based materials for processes involving carbon-carbon bond cleavage, including petroleum hydrocracking and coal liquefaction, offers the potential for decreasing catalyst costs as well as reducing the need for expensive catalyst recovery and recycling steps. Carbon-carbon bond cleavage catalysts produced in situ at reaction conditions from nanocrystalline hydrated iron oxides, show high activity and selectivity in model compound studies. Two highly active catalyst precursors, ferric oxyhydroxysulfate (OHS) and 6-line ferrihydrite, can be produced by a flow-through hydrothermal powder synthesis method, the Rapid Thermal Decomposition of precursors in Solution (RTDS) process. Model compound studies indicate that both catalyst precursors are active at a 400 C reaction temperature, but that there are significant differences in their catalytic characteristics. The activity of 6-line ferrihydrite is highly dependent on the particle (aggregate) size whereas the activity of the OHS is essentially independent of particle size. These differences are attributed to variations in the crystallite aggregation and particle surface characteristics of the two catalyst precursor materials. Catalytic activity is retained to lower reaction temperatures in tests using OHS than in similar tests using 6-line ferrihydrite.

  18. Ferric chloride graphite intercalation compounds prepared from graphite fluoride

    NASA Technical Reports Server (NTRS)

    Hung, Ching-Cheh

    1994-01-01

    The reaction between graphite fluoride and ferric chloride was observed in the temperature range of 300 to 400 C. The graphite fluorides used for this reaction have an sp3 electronic structure and are electrical insulators. They can be made by fluorinating either carbon fibers or powder having various degrees of graphitization. Reaction is fast and spontaneous and can occur in the presence of air. The ferric chloride does not have to be predried. The products have an sp2 electronic structure and are electrical conductors. They contain first stage FeCl3 intercalated graphite. Some of the products contain FeCl2*2H2O, others contain FeF3 in concentrations that depend on the intercalation condition. The graphite intercalated compounds (GIC) deintercalated slowly in air at room temperature, but deintercalated quickly and completely at 370 C. Deintercalation is accompanied by the disappearing of iron halides and the formation of rust (hematite) distributed unevenly on the fiber surface. When heated to 400 C in pure N2 (99.99 vol %), this new GIC deintercalates without losing its molecular structure. However, when the compounds are heated to 800 C in quartz tube, they lost most of its halogen atoms and formed iron oxides (other than hematite), distributed evenly in or on the fiber. This iron-oxide-covered fiber may be useful in making carbon-fiber/ceramic-matrix composites with strong bonding at the fiber-ceramic interface.

  19. Preliminary toxicological study of ferric acetyl acetonate

    SciTech Connect

    London, J.E.; Smith, D.M.

    1983-01-01

    The calculated acute oral LD/sub 50//sup 30/ (lethal does for 50% of the animals occuring with 30 days after compound administration) values for ferric acetyl acetonate were 584 mg/kg in mice and 995 mg/kg in rats. According to classical guidelines, this compound would be considered slightly toxic in both species. Skin application studies in the rabbit demonstrated the compound to be irritating. The eye irritation study disclosed the compound to be a severe irritant causing permanent damage to the cornea (inflammation and scarring resulting in blindness). The sensitization study in the guinea pig did not show ferric acetyl acetonate to be deleterious in this regard.

  20. Synthesis and phase transformations involving scorodite, ferric arsenate and arsenical ferrihydrite: Implications for arsenic mobility

    SciTech Connect

    Paktunc, D.; Dutrizac, J.; Gertsman, V.

    2008-07-07

    Scorodite, ferric arsenate and arsenical ferrihydrite are important arsenic carriers occurring in a wide range of environments and are also common precipitates used by metallurgical industries to control arsenic in effluents. Solubility and stability of these compounds are controversial because of the complexities in their identification and characterization in heterogeneous media. To provide insights into the formation of scorodite, ferric arsenate and ferrihydrite, series of synthesis experiments were carried out at 70 C and pH 1, 2, 3 and 4.5 from 0.2 M Fe(SO{sub 4}){sub 1.5} solutions also containing 0.02--0.2 M Na{sub 2}HAsO{sub 4}. The precipitates were characterized by transmission electron microscopy, X-ray diffraction and X-ray absorption fine structure techniques. Ferric arsenate, characterized by two broad diffuse peaks on the XRD pattern and having the structural formula of FeAsO{sub 4}{center_dot}4-7H{sub 2}O, is a precursor to scorodite formation. As defined by As XAFS, the local structure of ferric arsenate is profoundly different than that of scorodite. It is postulated that the ferric arsenate structure is made of single chains of corner-sharing Fe(O,OH){sub 6} octahedra with bridging arsenate tetrahedra alternating along the chains. Scorodite was precipitated from solutions with Fe/As molar ratios of 1 over the pH range of 1--4.5. The pH strongly controls the kinetics of scorodite formation and its transformation from ferric arsenate. The scorodite crystallite size increased from 7 to 33 nm by ripening and aggregation. Precipitates, resulting from continuous synthesis at pH 4.5 from solutions having Fe/As molar ratios ranging from 1 to 4 and resembling the compounds referred to as ferric arsenate, arsenical ferrihydrite and As-rich hydrous ferric oxide in the literature, represent variable mixtures of ferric arsenate and ferrihydrite. When the Fe/As ratio increases, the proportion of ferrihydrite increases at the expense of ferric arsenate. Arsenate adsorption appears to retard ferrihydrite growth in the precipitates with molar Fe/As ratios of 1--4, whereas increased reaction gradually transforms two-line ferrihydrite to six-line ferrihydrite at Fe/As ratios of 5 and greater.

  1. 21 CFR 184.1304 - Ferric pyrophosphate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Ferric pyrophosphate. 184.1304 Section 184.1304 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 184.1301 - Ferric phosphate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Ferric phosphate. 184.1301 Section 184.1301 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 184.1304 - Ferric pyrophosphate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Ferric pyrophosphate. 184.1304 Section 184.1304 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. 21 CFR 184.1304 - Ferric pyrophosphate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Ferric pyrophosphate. 184.1304 Section 184.1304 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...

  5. 21 CFR 184.1301 - Ferric phosphate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ferric phosphate. 184.1301 Section 184.1301 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...

  6. 21 CFR 184.1301 - Ferric phosphate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Ferric phosphate. 184.1301 Section 184.1301 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...

  7. 21 CFR 184.1301 - Ferric phosphate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Ferric phosphate. 184.1301 Section 184.1301 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...

  8. 21 CFR 184.1304 - Ferric pyrophosphate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ferric pyrophosphate. 184.1304 Section 184.1304 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 §...

  9. 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

  10. A rotating disk study of silver dissolution with thiourea in the presence of ferric sulfate

    NASA Astrophysics Data System (ADS)

    Pesic, Batric; Seal, Thom

    1990-06-01

    The rotating disk technique was used to study silver dissolution with thiourea as a function of sulfuric acid, ferric sulfate, and thiourea concentrations. The effect of many foreign ions (Mn, Cu, Co, Ca, Na, etc.) and various additives was also examined. The dissolution of silver was zero order with sulfuric acid, first order with ferric sulfate, and second order with thiourea. Among the foreign ions, copper had a dramatically negative effect. The strong oxidants such as hydrogen peroxide and manganese dioxide were also detrimental for silver dissolution. According to the temperature effect studied (5 C to 35 C), the activation energy was 22.6 kJ/ mole. Silver does not dissolve with thiourea in the absence of ferric ions. Sulfuric acid does not participate in the dissolution reaction. The most important parameter for silver dissolution is the ferric sulfate/thiourea ratio. In excess ferric sulfate, a solid silver-thiourea complex is formed, which precludes transfer of silver into solution. In excess thiourea, the free thiourea reacts with formed solid silver-thiourea complex, and silver goes into the solution, predominantly as the dimers of AgTU+ 3 complexes. The solid silver-thiourea complex in question was characterized by various spectroscopic, microscopic, and chemical analysis techniques. According to chemical composition, it corresponds to Ag2SO23TUH2O compound.

  11. 21 CFR 582.5306 - Ferric sodium pyrophosphate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Ferric sodium pyrophosphate. 582.5306 Section 582.5306 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Dietary Supplements 1 § 582.5306 Ferric sodium pyrophosphate. (a) Product. Ferric sodium pyrophosphate....

  12. 21 CFR 73.1025 - Ferric ammonium citrate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Ferric ammonium citrate. 73.1025 Section 73.1025 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1025 Ferric ammonium citrate. (a) Identity. The color additive ferric ammonium...

  13. Understanding arsenate reaction kinetics with ferric hydroxides.

    PubMed

    Farrell, James; Chaudhary, Binod K

    2013-08-01

    Understanding arsenic reactions with ferric hydroxides is important in understanding arsenic transport in the environment and in designing systems for removing arsenic from potable water. Many experimental studies have shown that the kinetics of arsenic adsorption on ferric hydroxides is biphasic, where a fraction of the arsenic adsorption occurs on a time scale of seconds while full equilibrium may require weeks to attain. This research employed density functional theory modeling in order to understand the mechanisms contributing to biphasic arsenic adsorption kinetics. The reaction energies and activation barriers for three modes of arsenate adsorption to ferric hydroxides were calculated. Gibbs free energies of reaction depended on the net charge of the complexes, which is a function of the system pH value. Physical adsorption of arsenate to ferric hydroxide proceeded with no activation barrier, with Gibbs free energies of reaction ranging from -21 to -58 kJ/mol. The highest Gibbs free energies of reaction for physical adsorption resulted from negative charge assisted hydrogen bonding between H atoms on the ferric hydroxide and O atoms in arsenate. The conversion of physically adsorbed arsenate into monodentate surface complexes had Gibbs free energies of activation ranging from 62 to 73 kJ/mol, and Gibbs free energies of reaction ranging from -23 to -38 kJ/mol. The conversion of monodentate surface complexes to bidentate, binuclear complexes had Gibbs free energies of activation ranging from 79 to 112 kJ/mol and Gibbs free energies of reaction ranging from -11 to -55 kJ/mol. For release of arsenate from uncharged bidentate complexes, energies of activation as high as 167 kJ/mol were encountered. Increasingly negative charges on the complexes lowered the activation barriers for desorption of arsenate, and in complexes with -2 charges, the highest activation barrier was 65 kJ/mol. This study shows that the slow kinetics associated with arsenic adsorption and desorption can be attributed to the high Gibbs free energies of activation for forming and breaking bonds with the ferric hydroxide. PMID:23806140

  14. Understanding Arsenate Reaction Kinetics with Ferric Hydroxides

    PubMed Central

    Farrell, James; Chaudhary, Binod K.

    2015-01-01

    Understanding arsenic reactions with ferric hydroxides is important in understanding arsenic transport in the environment and in designing systems for removing arsenic from potable water. Many experimental studies have shown that the kinetics of arsenic adsorption on ferric hydroxides is biphasic, where a fraction of the arsenic adsorption occurs on a time scale of seconds while full equilibrium may require weeks to attain. This research employed density functional theory modeling in order to understand the mechanisms contributing to biphasic arsenic adsorption kinetics. The reaction energies and activation barriers for three modes of arsenate adsorption to ferric hydroxides were calculated. Gibbs free energies of reaction depended on the net charge of the complexes, which is a function of the system pH value. Physical adsorption of arsenate to ferric hydroxide proceeded with no activation barrier, with Gibbs free energies of reaction ranging from ?21 to ?58 kJ/mol. The highest Gibbs free energies of reaction for physical adsorption resulted from negative charge assisted hydrogen bonding between H atoms on the ferric hydroxide and O atoms in arsenate. The conversion of physically adsorbed arsenate into monodentate surface complexes had Gibbs free energies of activation ranging from 62 to 73 kJ/mol, and Gibbs free energies of reaction ranging from ?23 to ?38 kJ/mol. The conversion of monodentate surface complexes to bidentate, binuclear complexes had Gibbs free energies of activation ranging from 79 to 112 kJ/mol, and Gibbs free energies of reaction ranging from ?11 to ?55 kJ/mol. For release of arsenate from uncharged bidentate complexes, energies of activation as high as 167 kJ/mol were encountered. Increasingly negative charges on the complexes lowered the activation barriers for desorption of arsenate, and in complexes with ?2 charges, the highest activation barrier was 65 kJ/mol. This study shows that the slow kinetics associated with arsenic adsorption and desorption can be attributed to the high Gibbs free energies of activation for forming and breaking bonds with the ferric hydroxide. PMID:23806140

  15. Nickel hydroxide and other nanophase cathode materials for rechargeable batteries

    NASA Astrophysics Data System (ADS)

    Reisner, David E.; Salkind, Alvin J.; Strutt, Peter R.; Xiao, T. Danny

    The staff of US Nanocorp, Inc. are developing unique nanostructured materials for a wide range of applications in the areas of energy storage (batteries and ultracapacitors) and energy conversion (fuel cells and thermoelectric) devices. Many of the preparations of these materials exploit a wet synthesis process (patent pending) that is scaleable to large volume manufacturing and anticipated to be low in cost. Specifically, both the ?-form of nickel hydroxide and the hollandite form of manganese dioxide have been synthesized. The hexagonal Ni(OH) 2 is anticipated to significantly boost energy densities in nickel-alkaline batteries, including nickel/cadmium, nickel/metal hydride and nickel/zinc. The nanophase MnO 2 microstructure exhibits an unusual tunnelled tubular geometry within a 'bird's nest' superstructure, and is expected to be of interest as an intercalation cathode material in lithium-ion systems as well as a catalyst for fuel cells. Characterization of these materials has been by the techniques of high resolution SEM and TEM, as well as XRD. Both Hg porosimetry and BET surface measurements for conventional and spherical nickel hydroxides are summarized. Pore distribution and electrochemical activity for the nanophase materials will be examined in the future.

  16. Wetting of nanophases: Nanobubbles, nanodroplets and micropancakes on hydrophobic surfaces.

    PubMed

    An, Hongjie; Liu, Guangming; Craig, Vincent S J

    2015-08-01

    The observation by Atomic Force Microscopy of a range of nanophases on hydrophobic surfaces poses some challenging questions, not only related to the stability of these objects but also regarding their wetting properties. Spherical capped nanobubbles are observed to exhibit contact angles that far exceed the macroscopic contact angle measured for the same materials, whereas nanodroplets exhibit contact angles that are much the same as the macroscopic contact angle. Micropancakes are reported to consist of gas, in which case their wetting properties are mysterious. They should only be stable when the van der Waals forces act to thicken the film whereas for a gas, the van der Waals forces will always act to thin the film. Here we examine the available evidence and contribute some additional experiments in order to review our understanding of the wetting properties of these nanophases. We demonstrate that if in fact micropancakes consist of a contaminant their wetting properties can be explained, though the very high contact angles of nanobubbles remain unexplained. PMID:25128452

  17. Intravenous ferric carboxymaltose for anaemia in pregnancy

    PubMed Central

    2014-01-01

    Background Iron deficiency is a common nutritional deficiency amongst women of childbearing age. Peri-partum iron deficiency anaemia (IDA) is associated with significant maternal, fetal and infant morbidity. Current options for treatment are limited: these include oral iron supplementation, which can be ineffective and poorly tolerated, and red blood cell transfusions, which carry an inherent risk and should be avoided. Ferric carboxymaltose is a new treatment option that may be better tolerated. The study was designed to assess the safety and efficacy of iron deficiency anaemia (IDA) correction with intravenous ferric carboxymaltose in pregnant women with mild, moderate and severe anaemia in the second and third trimester. Methods Prospective observational study; 65 anaemic pregnant women received ferric carboxymaltose up to 15mg/kg between 24 and 40weeks of pregnancy (median 35weeks gestational age, SD 3.6). Treatment effectiveness was assessed by repeat haemoglobin (Hb) measurements and patient report of well-being in the postpartum period. Safety was assessed by analysis of adverse drug reactions and fetal heart rate monitoring during the infusion. Results Intravenous ferric carboxymaltose infusion significantly increased Hb values (p?ferric carboxymaltose in the treatment of iron deficiency anaemia in pregnancy. PMID:24667031

  18. Changes in calcium uptake by liver induced by ferric lactate.

    PubMed

    Anghileri, L J; Maleki, P; Robert, J

    1992-02-01

    In vitro and in vivo Ca(2+)-uptake by the liver is increased by ferric lactate. In vitro albumin and deferoxamine inhibit ferric lactate effects. Electrophoresis demonstrates the binding of ferric lactate to albumin. In vivo, ferric lactate induces a significant increase of Ca(2+)-uptake by liver, with a maximum of 2.9 nmol/g against 0.66 nmol/g for control livers (P less than 0.005) between 5 and 24 h after administration. This uptake modification is reversible, while the amount of iron (measured as 59Fe taken up) remains constant throughout the experiment. The affinity of ferric lactate for protein and the iron mass-dependence of Ca(2+)-uptake increase support for the hypothesis of a ferric lactate-cell membrane interaction rather than an iron-catalyzed cell injury by lipid peroxidation as the major event leading to an increased Ca(2+)-uptake. PMID:1531001

  19. High Strain Rate Response of Sandwich Composites with Nanophased Cores

    NASA Astrophysics Data System (ADS)

    Mahfuz, Hassan; Uddin, Mohammed F.; Rangari, Vijaya K.; Saha, Mrinal C.; Zainuddin, Shaik; Jeelani, Shaik

    2005-05-01

    Polyurethane foam materials have been used as core materials in a sandwich construction with S2-Glass/SC-15 facings. The foam material has been manufactured from liquid polymer precursors of polyurethane. The precursors are made of two components; part-A (diphenylmethane diisocyanate) and part-B (polyol). In one set of experiments, part-A was mixed with part-B to manufacture the foam. In another set, TiO2 nanoparticles have been dispersed in part-A through ultrasonic cavitation technique. The loading of nanoparticles was 3% by weight of the total polymer precursor. The TiO2 nanoparticles were spherical in shape, and were about 29 nm in diameter. Sonic cavitation was carried out with a vibrasound liquid processor at 20 kHz frequency with a power intensity of about 100 kW/m2. The two categories of foams manufactured in this manner were termed as neat and nanophased. Sandwich composites were then fabricated using these two categories of core materials using a co-injection resin transfer molding (CIRTM) technique. Test samples extracted from the panel were subjected to quasi-static as well as high strain rate loadings. Rate of loading varied from 0.002 s-1 to around 1300 s-1. It has been observed that infusion of nanoparticles had a direct correlation with the cell geometry. The cell dimensions increased by about 46% with particle infusion suggesting that nanoparticles might have worked as catalysts during the foaming process. Correspondingly, enhancement in thermal properties was also noticed especially in the TGA experiments. There was also a significant improvement in mechanical properties due to nanoparticle infusion. Average increase in sandwich strength and energy absorption with nanophased cores was between 40 60% over their neat counterparts. Details of manufacturing and analyses of thermal and mechanical tests are presented in this paper.

  20. Catalytic decomposition of hydrogen peroxide by ferric ion in dilute sulfuric acid solutions

    NASA Astrophysics Data System (ADS)

    Eary, L. E.

    1985-06-01

    Hydrogen peroxide decomposition in acidic solutions is catalyzed by the free ferric ion, Fe3+. The following rate law for this reaction is determined by the initial rate method in solutions similar to those used for acidic in situ uranium leaching: - (dm_{H_2 O_2 } /dt)_{25^circ C} = k{(m_{H_2 O_2 } )(m_{Fe} 3 - )}/{(m_H - )} where k = 4.3 10-3 s1 at 25 C. From 25 to 50 C, the activation energy is 85.6 kJ/mol. The decomposition of hydrogen peroxide proceeds by a particular redox reaction sequence that depends on the ratio of the concentrations of hydrogen peroxide to free ferric ion. The rate law determined here is consistent with the form derived from the redox sequence for the case where the ratio of hydrogen peroxide to free ferric ion concentration is greater than 1.0. The magnitude of the rate constant indicates that the decomposition of hydrogen peroxide may cause rapid loss of this oxidant in leaching solutions containing ferric ion.

  1. Proximal Ligand Electron Donation and Reactivity of the Cytochrome P450 Ferric-Peroxo Anion

    PubMed Central

    Sivaramakrishnan, Santhosh; Ouellet, Hugues; Matsumura, Hirotoshi; Guan, Shenheng; Monne-Loccoz, Pierre; Burlingame, Alma L.

    2012-01-01

    CYP125 from Mycobacterium tuberculosis catalyzes sequential oxidation of the cholesterol side-chain terminal methyl group to the alcohol, aldehyde, and finally acid. Here, we demonstrate that CYP125 simultaneously catalyzes the formation of five other products, all of which result from deformylation of the sterol side chain. The aldehyde intermediate is shown to be the precursor of both the conventional acid metabolite and the five deformylation products. The acid arises by protonation of the ferric-peroxo anion species and formation of the ferryl-oxene species, also known as Compound I, followed by hydrogen abstraction and oxygen transfer. The deformylation products arise by addition of the same ferric-peroxo anion to the aldehyde intermediate to give a peroxyhemiacetal that leads to C-C bond cleavage. This bifurcation of the catalytic sequence has allowed us to examine the effect of electron donation by the proximal ligand on the properties of the ferric-peroxo anion. Replacement of the cysteine thiolate iron ligand by a selenocysteine results in UV-vis, EPR, and resonance Raman spectral changes indicative of an increased electron donation from the proximal selenolate ligand to the iron. Analysis of the product distribution in the reaction of the selenocysteine substituted enzyme reveals a gain in the formation of the acid (Compound I pathway) at the expense of deformylation products. These observations are consistent with an increase in the pKa of the ferric-peroxo anion, which favors its protonation and therefore Compound I formation. PMID:22444582

  2. More Evidence of the Importance of Amorphous Silicates in CM Carbonaceous Chondrites: New Observations from a Fine-Grained Rim in the CM2 Chondrite, TIL 91722

    NASA Astrophysics Data System (ADS)

    Brearley, A. J.; Le Guillou, C.

    2015-07-01

    A fine-grained rim in TIL 91722 contains abundant amorphous silicate material containing nanophase sulfides. Phyllosilicates are rare. The amorphous material has a high ferric iron content indicative of oxidation coupled with hydration.

  3. 46 CFR 151.50-75 - Ferric chloride solution.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Ferric chloride solution. 151.50-75 Section 151.50-75... CARRYING BULK LIQUID HAZARDOUS MATERIAL CARGOES Special Requirements 151.50-75 Ferric chloride solution... solution must be lined with rubber, corrosion resistant plastic, or a material approved by the...

  4. 46 CFR 151.50-75 - Ferric chloride solution.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Ferric chloride solution. 151.50-75 Section 151.50-75... CARRYING BULK LIQUID HAZARDOUS MATERIAL CARGOES Special Requirements 151.50-75 Ferric chloride solution... solution must be lined with rubber, corrosion resistant plastic, or a material approved by the...

  5. 46 CFR 151.50-75 - Ferric chloride solution.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Ferric chloride solution. 151.50-75 Section 151.50-75... CARRYING BULK LIQUID HAZARDOUS MATERIAL CARGOES Special Requirements 151.50-75 Ferric chloride solution... solution must be lined with rubber, corrosion resistant plastic, or a material approved by the...

  6. 46 CFR 151.50-75 - Ferric chloride solution.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Ferric chloride solution. 151.50-75 Section 151.50-75... CARRYING BULK LIQUID HAZARDOUS MATERIAL CARGOES Special Requirements 151.50-75 Ferric chloride solution... solution must be lined with rubber, corrosion resistant plastic, or a material approved by the...

  7. 46 CFR 151.50-75 - Ferric chloride solution.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Ferric chloride solution. 151.50-75 Section 151.50-75... CARRYING BULK LIQUID HAZARDOUS MATERIAL CARGOES Special Requirements 151.50-75 Ferric chloride solution... solution must be lined with rubber, corrosion resistant plastic, or a material approved by the...

  8. 21 CFR 582.5306 - Ferric sodium pyrophosphate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Ferric sodium pyrophosphate. 582.5306 Section 582.5306 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 1 582.5306 Ferric...

  9. Energy transduction by anaerobic ferric iron respiration in Thiobacillus ferrooxidans

    SciTech Connect

    Pronk, J.T.; Liem, K.; Bos, P.; Kuenen, J.G. )

    1991-07-01

    Formate-grown cells of the obligately chemolithoautotrophic acidophile Thiobacillus ferrooxidans were capable of formate- and elemental sulfur-dependent reduction of ferric iron under anaerovic conditions. Under aerobic conditions, both oxygen and ferric iron could be simultaneously used as electron acceptors. To investigate whether anaerobic ferric iron respiration by T. ferrooxidans is an energy-transducing process, uptake of amino acids was studied. Glycine uptake by starved cells did not occur in the absence of an electron donor, neither under aerobic conditions nor under anaerobic conditions. Uptake of glycine could be driven by formate- and ferrous iron-dependent oxygen uptake. Under anaerobic conditions, ferric iron respiration with the electron donors formate and elemental sulfur could energize glycine uptake. Glycine uptake was inhibited by the uncoupler 2,4-dinitrophenol. The results indicate that anaerobic ferric iron respiration can contribute to the energy budget of T. ferrooxidans.

  10. Bioproduction of ferric sulfate used during heavy metals removal from sewage sludge.

    PubMed

    Drogui, Patrick; Mercier, Guy; Blais, Jean-Franois

    2005-01-01

    Toxic metals removal from wastewater sewage sludge can be achieved through microbial processes involving Acidithiobacillus ferrooxidans. The oxidation of ferrous ions by A. ferrooxidans, cultured in sewage sludge filtrate, was studied in both batch and continuous flow stirred tank reactors. Sewage sludge filtrate containing natural nutrients (phosphorus and nitrogen) was recovered as effluent following the dehydration of a primary and secondary sludge mixture. Batch and continuous flow stirred tank reactor tests demonstrated that A. ferrooxidans were able to grow and completely oxidize ferrous iron in a culture medium containing more than 80% (v v(-1)) sewage sludge filtrate with 10 g Fe(II) L(-1) added. Toxic levels were reached when total organic carbon in the sewage sludge filtrate exceeded 250 mg L(-1). The ferric iron solution produced in the sludge filtrate by A. ferrooxidans was used to solubilize heavy metals in primary and secondary sludge. The solubilization of Cu, Cr, and Zn yielded 71, 49, and 80%, respectively. This is comparable with the yield percentages obtained using a FeCl(3) solution. The cost of treating wastewater sewage sludge by bioproducing a ferric ion solution from sewage sludge is three times less expensive than the conventional method requiring a commercial ferric chloride solution. PMID:15843644

  11. The Formation of High-Coercivity, Oriented, Nanophase Cobalt Precipitates in Al

    SciTech Connect

    Honda, S.; Modine, F.A.; Haynes, T.E.; Meldrum, A.; Budai, J.D.; SOng, K.J.; Thompson, J.R.; Boatner, L.A.

    1999-11-29

    Ion-implantation and thermal-processing methods have been used to form nanophase magnetic precipitates of metallic cobalt that are embedded in the near-surface region of single crystals of Al{sub 2}O{sub 3}. The Co precipitates are isolated, single-crystal particles that are crystallographically oriented with respect to the host Al{sub 2}O{sub 3} lattice. Embedded nanophase Co precipitates were formed by the implantation of Co+ at an energy of 140 keV and a dose of 8 x l0{sup 16} ions/cm{sup 2} followed by annealing in a reducing atmosphere. The implanted/annealed Co depth profile, particle size distributions and shapes, and the orientational relationship between the nanophase precipitates and the host crystal lattice were determined using RBS/channeling, transmission electron microscopy, and x-ray diffraction.

  12. Nanophase Fe alloys consolidated to full density from mechanically milled powders

    SciTech Connect

    He, L.; Allard, L. F.; Breder, K.; Ma, E.

    2000-04-01

    Nanophase elemental Fe powders prepared by mechanical milling were sinter forged to full density with an average grain size in the nanophase range (below 100 nm). If Cu additions are introduced during milling to form supersaturated solid solutions (Fe{sub 85}Cu{sub 15} and Fe{sub 60}Cu{sub 40}), grain sizes can be easily controlled to below 50 nm after consolidation. For Fe-Cu, it was observed that atomic level alloying between the two elements during milling was very helpful for obtaining a homogeneous microstructure and nanocrystalline grain/domain sizes in the consolidated product. The advantages of using sinter forging (upset die forging), as well as the role of the Cu addition, in the retention of nanocrystalline grain sizes are discussed. The consolidated Fe alloys exhibit very high strength under compression, further demonstrating that low populations of flaws and nanophase grain structures were attained in the consolidated products. (c) 2000 Materials Research Society.

  13. Surface Enthalpies of Nanophase ZnO with Different Morphologies

    SciTech Connect

    Zhang, Peng; Xu, Fen; Navrotsky, Alexandra; Lee, Jong Soo; Kim, Sangtae; Liu, Jun

    2007-11-13

    A direct calorimetric measurement of the dependence of the surface enthalpy of nanophase ZnO on morphology is reported. Nanoparticles, nanoporous composites, nanorods, and nanotetrapods were prepared with various sizes and their surface enthalpies were derived from their drop solution enthalpies in molten sodium molybdate. Water adsorption calorimetry for nanoparticles and nanorods was carried out to characterize the stabilization effect of surface hydration. The surface enthalpies of hydrated surfaces for nanoparticles, nanoporous composites, nanorods and nanotetrapods are 1.31±0.07, 1.42±0.21, 5.19±0.56, and 5.77±2.50 J/m2, respectively, while those of the anhydrous surfaces are 2.55±0.23, 2.74±0.16, 6.67±0.56, and 7.28±2.50 J/m2. The surface enthalpies of nanoparticles are the same as those of nanoporous composites, and are much lower than those of nanorods and nanotetrapods, which are also close to each other. The dependence of surface enthalpy on morphology is discussed in terms of exposed surface structures. This is the first time that calorimetry on nanocrystalline powders bas been able to detect differences in surface energetics of materials having different morphologies.

  14. Nanophase hydroxyapatite as a biomaterial in advanced hard tissue engineering: a review.

    PubMed

    Zakaria, Siti Maisurah; Sharif Zein, Sharif Hussein; Othman, Mohd Roslee; Yang, Fang; Jansen, John A

    2013-10-01

    Hydroxyapatite is a biocompatible material that is extensively used in the replacement and regeneration of bone material. In nature, nanostructured hydroxyapatite is the main component present in hard body tissues. Hence, the state of the art in nanotechnology can be exploited to synthesize nanophase hydroxyapatite that has similar properties with natural hydroxyapatite. Sustainable methods to mass-produce synthetic hydroxyapatite nanoparticles are being developed to meet the increasing demand for these materials and to further develop the progress made in hard tissue regeneration, especially for orthopedic and dental applications. This article reviews the current developments in nanophase hydroxyapatite through various manufacturing techniques and modifications. PMID:23557483

  15. In vivo distribution of ferric-ATP complex.

    PubMed

    Anghileri, L J; Robert, J

    1994-01-01

    At physiological pH, ferric-ATP complex presents ionic characteristics unlike those of ferric lactate. Its rapid diffusion into the tissues, and its reactivity which is not impaired by polymerization seem responsible for its toxicity. In comparison with ferric lactate, after parenteral administration there is a much higher spleen, lung, kidney and bone accumulation. After oral administration, on the other hand, the values are lower. ATP hydrolysis by the stomach's pH, and the subsequent iron insolubilization as phosphate could be the reason for this behaviour. PMID:7957445

  16. Ferric chloride based downstream process for microalgae based biodiesel production.

    PubMed

    Seo, Yeong Hwan; Sung, Mina; Kim, Bohwa; Oh, You-Kwan; Kim, Dong Yeon; Han, Jong-In

    2015-04-01

    In this study, ferric chloride (FeCl3) was used to integrate downstream processes (harvesting, lipid extraction, and esterification). At concentration of 200 mg/L and at pH 3, FeCl3 exhibited an expected degree of coagulation and an increase in cell density of ten times (170 mg/10 mL). An iron-mediated oxidation reaction, Fenton-like reaction, was used to extract lipid from the harvested biomass, and efficiency of 80% was obtained with 0.5% H2O2 at 90 C. The iron compound was also employed in the esterification step, and converted free fatty acids to fatty acid methyl esters under acidic conditions; thus, the fatal problem of saponification during esterification with alkaline catalysts was avoided, and esterification efficiency over 90% was obtained. This study clearly showed that FeCl3 in the harvesting process is beneficial in all downstream steps and have a potential to greatly reduce the production cost of microalgae-originated biodiesel. PMID:25647024

  17. Stability of phosphorus within a wetland soil following ferric chloride treatment to control eutrophication.

    PubMed

    Sherwood, L J; Qualls, R G

    2001-10-15

    Addition of iron and aluminum compounds has become an increasingly popular method to regulate phosphorus eutrophication in lakes and reservoirs. It has been proposed that ferric chloride addition to agricultural runoff entering the northern Everglades could provide a means for enhancing natural mechanisms of phosphorus removal from the wetland. In this study we added ferric chloride to Everglades water spiked with 32PO4, incubating the resulting precipitates in microcosms simulating the Everglades ecosystem. 32P activity and reduction-oxidation (redox) potentials were monitored to determine if the 32P was released into the overlying water column due to iron reduction. Results of redox potential measurements and 32P activity indicate that although reducing conditions exist in the soil, on average less than 1% of the added 32P was measured in the water column during the 139-day incubation. Ferric chloride addition thus might prove an effective means of long-term phosphorus retention in the Florida Everglades and perhaps other wetland systems. PMID:11686376

  18. 21 CFR 73.2298 - Ferric ammonium ferrocyanide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2298 Ferric ammonium ferrocyanide. (a... ferrocyanide is safe for use in coloring externally applied cosmetics, including cosmetics applied to the...

  19. 21 CFR 73.2298 - Ferric ammonium ferrocyanide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2298 Ferric ammonium ferrocyanide. (a... ferrocyanide is safe for use in coloring externally applied cosmetics, including cosmetics applied to the...

  20. 21 CFR 73.2298 - Ferric ammonium ferrocyanide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2298 Ferric ammonium ferrocyanide. (a... ferrocyanide is safe for use in coloring externally applied cosmetics, including cosmetics applied to the...

  1. 21 CFR 73.2298 - Ferric ammonium ferrocyanide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2298 Ferric ammonium ferrocyanide. (a... ferrocyanide is safe for use in coloring externally applied cosmetics, including cosmetics applied to the...

  2. 21 CFR 73.2298 - Ferric ammonium ferrocyanide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2298 Ferric ammonium ferrocyanide. (a... ferrocyanide is safe for use in coloring externally applied cosmetics, including cosmetics applied to the...

  3. Limit of miscibility and nanophase separation in associated mixtures.

    PubMed

    Artola, P A; Raihane, A; Crauste-Thibierge, C; Merlet, D; Emo, M; Alba-Simionesco, C; Rousseau, B

    2013-08-22

    We present a detailed analysis of the mixing process in an associating system, the water-tert-butanol (2-methyl-2-propanol) mixture. Using molecular dynamics simulations, together with neutron, X-ray diffraction experiments, and pulsed gradient spin-echo NMR, we study the local structure and dynamic properties over the full concentration range, and thereby provide quantitative data that reveal relationships between local structure and macroscopic behavior. For an alcohol-rich mixture, diffraction patterns from both neutron and X-ray experiments exhibit a peak at low wavelength vector (q ≈ 0.7 Å(-1)) characteristic of supermolecular structures. On increasing the water content, this "prepeak" progressively flattens and shifts to low wave vector . We identify hydrogen bonds in the system as the driving force for the specific organization that appears in mixtures, and provide an analysis of the variation of the cluster size distribution with composition. We find that the sizes of local hydrogen-bonded clusters observed in alcohol-rich mixtures become larger as the mole fraction, x(w), of water is increased; a nanophase separation is seen for x(w) in the range 0.6-0.7. This corresponds to several changes in some macroscopic properties of the liquid mixture. Thus, we propose a microscopic description of the effect of water addition in alcohol, which is in agreement with both neutron diffraction pattern and mobility of water and alcohol species. In summary we present a full and comprehensive description of miscibility at its limit in an associated system. PMID:23937163

  4. Comparing polyaluminum chloride and ferric chloride for antimony removal.

    PubMed

    Kang, Meea; Kamei, Tasuku; Magara, Yasumoto

    2003-10-01

    Antimony has been one of the contaminants required to be regulated, however, only limited information has been collected to date regarding antimony removal by polyaluminium chloride (PACl) and ferric chloride (FC). Accordingly, the possible use of coagulation by PACl or FC for antimony removal was investigated. Jar tests were used to determine the effects of solution pH, coagulant dosage, and pre-chlorination on the removal of various antimony species. Although high-efficiency antimony removal by aluminum coagulation has been expected because antimony is similar to arsenic in that both antimony and arsenic are a kind of metalloid in group V of the periodic chart, this study indicated: (1) removal density (arsenic or antimony removed per mg coagulant) for antimony by PACl was about one forty-fifth as low as observed for As(V); (2) although the removal of both Sb(III) and Sb(V) by coagulation with FC was much higher than that of PACl, a high coagulant dose of 10.5mg of FeL(-1) at optimal pH of 5.0 was still not sufficient to meet the standard antimony level of 2 microg as SbL(-1) for drinking water when around 6 microg as SbL(-1) were initially present. Consequently, investigation of a more appropriate treatment process is necessary to develop economical Sb reduction; (3) although previous studies concluded that As(V) is more effectively removed than As(III), this study showed that the removal of Sb(III) by coagulation with FC was much more pronounced than that of Sb(V); (4) oxidation of Sb(III) with chlorine decreased the ability of FC to remove antimony. Accordingly, natural water containing Sb(III) under anoxic condition should be coagulated without pre-oxidation. PMID:12946899

  5. Ferric microperoxidase-11 catalyzes peroxynitrite isomerization.

    PubMed

    Ascenzi, Paolo; Leboffe, Loris; Santucci, Roberto; Coletta, Massimo

    2015-03-01

    Microperoxidase-11 (MP11) is an undecapeptide derived from horse heart cytochrome c offering the possibility to study the reactivity of the heme group relatively unshielded by the protein. Here, the peroxynitrite isomerization to NO3(-) catalyzed by ferric MP11 (MP11-Fe(III)) is reported. Data were obtained between pH3.6 and 8.1, at 20.0C. The value of the second-order rate constant (kon) for peroxynitrite isomerization to NO3(-) by MP11-Fe(III) decreases from (1.10.1)10(5)M(-1)s(-1), at pH3.6, to (6.10.6)10(3)M(-1)s(-1), at pH8.1. The pH dependence of kon (pKa=6.9) suggests that peroxynitrous acid reacts preferentially with MP11-Fe(III). The MP11-Fe(III)-catalyzed isomerization of peroxynitrite to NO3(-) has been ascribed to the reactive penta-coordinated heme-Fe atom of MP11-Fe(III). In fact, cyanide binding to the sixth coordination position of the heme-Fe atom inhibits the MP11-Fe(III)-catalyzed isomerization of peroxynitrite to NO3(-). The values of the first-order rate constant (k0) for isomerization of peroxynitrite to NO3(-) in the presence of the MP11-Fe(III)-CN complex are superimposable to those obtained in the absence of MP-Fe(III). Values of kon for peroxynitrite isomerization to NO3(-) by MP11-Fe(III) overlap those obtained for penta-coordinated cardiolipin-cytochrome c complex and for carboxymethylated cytochrome c in absence and presence of cardiolipin. Present results highlight the role of the heme-Fe(III) co-ordination state in the modulation of cytochrome c reactivity. PMID:25578411

  6. Hydrogen and Ferric Iron in Mars Materials

    NASA Technical Reports Server (NTRS)

    Dyar, Melinda D.

    2004-01-01

    Knowledge of oxygen and hydrogen fugacity is of paramount importance in constraining phase equilibria and crystallization processes of melts, as well as understanding the partitioning of elements between the cope and silicate portions of terrestrial planets. H and Fe(3+) must both be analyzed in order to reconstruct hydrogen and oxygen fugacities on Mars. To date, SIMS data have elucidated D/H and H contents of hydrous phases in SNC meteorites, but until now anhydrous martian minerals have not been systematically examined for trace hydrogen. Ferric iron has been quantified using XANES in many martian phases, but integrated studies of both Fe(3+) and H on the same spots are really needed to address the H budget. Finally, the effects of shock on both Fe(3+) and H in hydrous and anhydrous phases must be quantified. Thus, the overall goal of this research was to understand the oxygen and hydrogen fugacities under which martian samples crystallized. In this research one-year project, we approached this problem by 1) characterizing Fe(3+) and H contents of SNC meteorites using both bulk (Mossbauer spectroscopy and uranium extraction, respectively) and microscale (synchrotron micro-XANES and SIMS) methods; 2) relating Fe(3+) and H contents of martian minerals to their oxygen and hydrogen fugacities through analysis of experimentally equilibrated phases (for pyroxene) and through study of volcanic rocks in which the oxygen and hydrogen fugacities can be independently constrained (for feldspar); and 3) studying the effects of shock processes on Fe(3+) and H contents of the phases of interest. Results have been used to assess quantitatively the distribution of H and Fe(3+) among phases in the martian interior, which will better constrain the geodynamic processes of the interior, as well as the overall hydrogen and water budgets on Mars. There were no inventions funded by this research.

  7. Thermal Properties of Phase Change Composites Containing Ferric Oxide Nanoparticles.

    PubMed

    Wang, Jifen; Xie, Huaqing; Li, Yang

    2015-04-01

    We prepared a series of homogeneous nanocomposites by suspending Fe2O3 nanoparticles into paraffin wax (PW) matrix. Fe2O3/PW nanocomposites have reduced both solid-solid phase change latent heat capacity (Ls-s) and solid-liquid phase change latent heat capacity (Ls-l) with an increase in the mass fraction of Fe2O3 nanoparticles. There is almost equable solid-solid phase change temperature (Ts-s) between PW and Fe2O3/PW composites, as well as melting temperature (Ts-l). Fe2O3 nanoparticle addition leads to substantial enhancement in the thermal conductivity of Fe2O3/PW and the enhancement ratio increases with the nanoparticle loading. Thermal conductivity of Fe2O3/PW composite with 3.0 wt% nanoparticles is about 0.27 W/(m K) at 15 C, which close to that of ?-Al2O3/PW with 5.0 wt% nanoparticles but higher than that of ZnO/PW containing 5.0 wt% nanoparticles. At 60 C, Fe2O3/PW has higher thermal conductivity than ?-A12O3/PW and ZnO/PW contained with same fraction of nanoparticles. PMID:26353577

  8. Magnetic phases in lunar fines - Metallic Fe or ferric oxides.

    NASA Technical Reports Server (NTRS)

    Tsay, F.-D.; Manatt, S. L.; Chan, S. I.

    1973-01-01

    The ferromagnetic resonance observed for the Apollo 11 and 12 lunar fines is characterized by an asymmetric lineshape with a narrower appearance on the high field side. This asymmetry together with an anisotropy energy which varies from +640 to +500 G over the temperature range of 80 to 298 K indicate that the ferromagnetic resonance arises from metallic Fe having the body-centered cubic structure and not from hematite, magnetite or other Fe(3+) ions in magnetite-like phases. The g-value, the lineshape asymmetry, and the temperature dependence of the linewidth for the Apollo 14 and 15 fines as reported by other workers are found to be essentially similar to those observed for the Apollo 11 and 12 fines.

  9. Coupled ferric oxides and sulfates on the Martian surface.

    PubMed

    Bibring, J-P; Arvidson, R E; Gendrin, A; Gondet, B; Langevin, Y; Le Mouelic, S; Mangold, N; Morris, R V; Mustard, J F; Poulet, F; Quantin, C; Sotin, C

    2007-08-31

    The Mars Exploration Rover (MER), Opportunity, showed that layered sulfate deposits in Meridiani Planum formed during a period of rising acidic ground water. Crystalline hematite spherules formed in the deposits as a consequence of aqueous alteration and were concentrated on the surface as a lag deposit as wind eroded the softer sulfate rocks. On the basis of Mars Express Observatoire pour la Minralogie, l'Eau, les Glaces et l'Activit (OMEGA) orbital data, we demonstrate that crystalline hematite deposits are associated with layered sulfates in other areas on Mars, implying that Meridiani-like ground water systems were indeed widespread and representative of an extensive acid sulfate aqueous system. PMID:17673623

  10. Nanophase hydroxyapatite coatings for dental and orthopedic applications

    NASA Astrophysics Data System (ADS)

    Sato, Michiko

    In order to improve dental and orthopedic implant performance, the objective of this study was to synthesize nanocrystalline hydroxyapatite (HA) powders to coat metals (specifically, titanium and tantalum). Precipitated HA powders were either sintered in order to produce UltraCaP HA (or microcrystalline size HA) or were treated hydrothermally to produce nanocrystalline HA. Some of the UltraCaP and nanocrystalline HA powders were doped with yttrium (Y) since previous in vitro studies demonstrated that Y-doped HA in bulk improved osteoblast (or bone-forming cell) function over undoped HA. The nanocrystalline HA powders were also mixed with nanophase titania powders because previous studies demonstrated that titania/HA composite coatings increased coating adhesive strength and HA nucleation. These powders were then deposited onto titanium by a novel room-temperature process, called IonTiteT(TM). The results demonstrated that the chemical properties and crystallite size of the original HA powders were maintained in the coatings. More importantly, in vitro studies showed increased osteoblast (bone-forming cell) adhesion on the single phase nanocrystalline HA and nano-titania/HA coatings compared to traditionally used plasma-sprayed HA coatings and uncoated metals. Results further demonstrated greater amounts of calcium deposition by osteoblasts cultured on nanocrystalline HA coatings compared to UltraCaP coatings and conventionally used plasma-sprayed HA coatings. To elucidate mechanisms that influenced osteoblast functions on the HA coatings, the amount of proteins (fibronectin and vitronectin) onto the HA powders and the adsorbed fibronectin conformation were investigated. Exposure of cell integrin binding domains (in fibronectin III10 segments) was greater in fibronectin adsorbed onto 1.2 mole% Y-doped UltraCaP HA coatings compared to nanocrystalline HA coatings tested. However, 1.2 mole% Y-doped UltraCaP HA coatings did not increase mineralization by osteoblasts compared to the nanocrystalline HA coatings. These results suggested that the availability of integrin binding domains in fibronectin did not correlate to enhanced mineralization by osteoblasts on nanocrystalline HA coatings. Lastly, undoped nanocrystalline HA coatings were studied using a well-established rat calvaria in vivo. Histological analysis showed that nanocrystalline HA coated on tantalum scaffolds increased bone and fibrous tissue infiltration into the scaffolds while uncoated and UltraCaP HA coated scaffolds did not after as early as 6 weeks. In summary, these results encourage further studies on nanocrystalline IonTiteTM HA coatings on various metals for orthopedic and dental applications.

  11. Nanophase Carbonates on Mars: Implications for Carbonate Formation and Habitability

    NASA Technical Reports Server (NTRS)

    Archer, P. Douglas, Jr.; Lauer, H. Vern; Ming, Douglas W.; Niles, Paul B.; Morris, Richard V.; Rampe, Elizabeth B.; Sutter, Brad

    2014-01-01

    Despite having an atmosphere composed primarily of CO2 and evidence for abundant water in the past, carbonate minerals have only been discovered in small amounts in martian dust [1], in outcrops of very limited extent [2, 3], in soils in the Northern Plains (the landing site of the 2007 Phoenix Mars Scout Mission) [4] and may have recently been detected in aeolian material and drilled and powdered sedimentary rock in Gale Crater (the Mars Science Laboratory [MSL] landing site) [5]. Thermal analysis of martian soils by instruments on Phoenix and MSL has demonstrated a release of CO2 at temperatures as low as 250-300 degC, much lower than the traditional decomposition temperatures of calcium or magnesium carbonates. Thermal decomposition temperature can depend on a number of factors such as instrument pressure and ramp rate, and sample particle size [6]. However, if the CO2 released at low temperatures is from carbonates, small particle size is the only effect that could have such a large impact on decomposition temperature, implying the presence of extremely fine-grained (i.e., "nanophase" or clay-sized) carbonates. We hypothesize that this lower temperature release is the signature of small particle-sized (clay-sized) carbonates formed by the weathering of primary minerals in dust or soils through interactions with atmospheric water and carbon dioxide and that this process may persist under current martian conditions. Preliminary work has shown that clay-sized carbonate grains can decompose at much lower temperatures than previously thought. The first work took carbonate, decomposed it to CaO, then flowed CO2 over these samples held at temperatures >100 degC to reform carbonates. Thermal analysis confirmed that carbonates were indeed formed and transmission electron microsopy was used to determine crystal sized were on the order of 10 nm. The next step used minerals such as diopside and wollastonite that were sealed in a glass tube with a CO2 and H2O source. After reacting these materials for a number of hours, thermal analysis demonstrated the formations of carbonates that decomposed at temperatures as low as 500 degC [7]. Further work is underway to carry out the weathering process under more Mars-like conditions (low pressure and low temperature) to determine if the carbonate decomposition temperature can be shifted to even lower temperatures, consistent with what has been detected by thermal analysis instruments on Mars.

  12. Reduction of ferric iron by L-lactate and DL-glycerol-3-phosphate in membrane preparations from Staphylococcus aureus and interactions with the nitrate reductase system.

    PubMed Central

    Lascelles, J; Burke, K A

    1978-01-01

    Membrane fractions with L-lactate dehydrogenase, sn-glycerol-3-phosphate (G3P) dehydrogenase, and nitrate reductase activities were prepared from Staphylococcus aureus wild-type and hem mutant strains. These preparations reduced ferric to ferrous iron with L-lactate or G3P as the source of reductant, using ferrozine to trap the ferrous iron. Reduction of ferric iron was insensitive to 2-heptyl-4-hydroxyquinoline-N-oxide (HQNO) with either L-lactate or G3P as reductant, but oxalate and dicumarol inhibited reduction with L-lactate as substrate. The membranes had L-lactate- and G3P-nitrate reductase activities, which were inhibited by azide and by HQNO. Reduction of ferric iron under anaerobic conditions was inhibited by nitrate with preparations from the wild-type strain. This effect of nitrate was abolished by blocking electron transport to the nitrate reductase system with azide or HQNO. Nitrate did not inhibit reduction of ferric iron in heme-depleted membranes from the hem mutant unless hemin was added to restore L-lactate- and G3P-nitrate reductase activity. We conclude that reduced components of the electron transport chain that precede cytochrome b serve as the source of reductant for ferric iron and that these components are oxidized preferentially by a functional nitrate reductase system. PMID:207671

  13. Nanophase Carbonates on Mars: Does Evolved Gas Analysis of Nanophase Carbonates Reveal a Large Organic Carbon Budget in Near-Surface Martian Materials?

    NASA Technical Reports Server (NTRS)

    Archer, P. Douglas, Jr.; Niles, Paul B.; Ming, Douglas W.; Sutter, Brad; Eigenbrode, Jen

    2015-01-01

    Evolved Gas Analysis (EGA), which involves heating a sample and monitoring the gases released, has been performed on Mars by the Viking gas chromatography/mass spectrometry instruments, the Thermal and Evolved Gas Analyzer (TEGA) on the Phoenix lander, and the Sample Analysis at Mars (SAM) instrument on the Mars Science Laboratory. All of these instruments detected CO2 released during sample analysis at abundances of approx. 0.1 to 5 wt% assuming a carbonate source. The source of the CO2 can be constrained by evaluating the temperature of the gas release, a capability of both the TEGA and SAM instruments. The samples analyzed by SAM show that the majority of the CO2 is released below 400C, much lower than traditional carbonate decomposition temperatures which can be as low as 400C for some siderites, with magnesites and calcites decomposing at even higher temperatures. In addition to mineralogy, decomposition temperature can depend on particle size (among other factors). If carbonates formed on Mars under low temperature and relative humidity conditions, the resulting small particle size (nanophase) carbonates could have low decomposition temperatures. We have found that calcite can be synthesized by exposing CaO to water vapor and CO2 and that the resulting mineral has an EGA peak of approx. 550C for CO2, which is about 200C lower than for other calcites. Work is ongoing to produce Fe and Mg-bearing carbonates using the same process. Current results suggest that nanophase calcium carbonates cannot explain the CO2 released from martian samples. If the decomposition temperatures of Mg and Fe-bearing nanophase carbonates are not significantly lower than 400C, other candidate sources include oxalates and carboxylated organic molecules. If present, the abundance of organic carbon in these samples could be greater than 0.1 wt % (1000s of ppm), a signficant departure from the paradigm of the organic-poor Mars based on Viking results.

  14. Preparation of silica nanospheres and porous polymer membranes with controlled morphologies via nanophase separation

    NASA Astrophysics Data System (ADS)

    Lee, Jung-Pil; Choi, Sinho; Park, Soojin

    2012-08-01

    We successfully synthesized two different structures, silica nanospheres and porous polymer membranes, via nanophase separation, based on a sol-gel process. Silica sol, which was in situ polymerized from tetraorthosilicate, was used as a precursor. Subsequently, it was mixed with a polymer that was used as a matrix component. It was observed that nanophase separation occurred after the mixing of polymer with silica sol and subsequent evaporation of solvents, resulting in organizing various structures, from random network silica structures to silica spheres. In particular, silica nanospheres were produced by manipulating the mixing ratio of polymer to silica sol. The size of silica beads was gradually changed from micro- to nanoscale, depending on the polymer content. At the same time, porous polymer membranes were generated by removing the silica component with hydrofluoric acid. Furthermore, porous carbon membranes were produced using carbon source polymer through the carbonization process.

  15. Nanophase Magnetite and Pyrrhotite in ALH84001 Martian Meteorite: Evidence for an Abiotic Origin

    NASA Technical Reports Server (NTRS)

    Golden, D. C.; Lauer, H. V., Jr. III; Ming, D. W.; Morris, R. V.

    2006-01-01

    The nanophase magnetite crystals in the black rims of pancake-shaped carbonate globules of the Martian meteorite ALH84001 have been studied extensively because of the claim by McKay et al.that they are biogenic in origin. A subpopulation of these magnetite crystals are reported to conform to a unique elongated shape called "truncated hexa-octahedral" or "THO" by Thomas-Keprta et al. They claim these THO magnetite crystals can only be produced by living bacteria thus forming a biomarker in the meteorite. In contrast, thermal decomposition of Fe-rich carbonate has been suggested as an alternate hypothesis for the elongated magnetite formation in ALH84001 carbonates. The experimental and observational evidence for the inorganic formation of nanophase magnetite and pyrrhotite in ALH84001 by decomposition of Fe-rich carbonate in the presence of pyrite are provided.

  16. Comparison of periodontal ligament cells responses to dense and nanophase hydroxyapatite.

    PubMed

    Sun, Weibin; Chu, Chenlin; Wang, Juan; Zhao, Huating

    2007-05-01

    Hydroxyapatite, a synthetic calcium phosphate ceramic, is used as a biomaterial for the restoration of human hard tissue as well as in techniques which aim to regenerate periodontal tissues. Generally, hydroxyapatite is believed to have osteoconductive effects and to be non-bioresorbable but not to induce to periodontal tissue regeneration. No report has been found on responses of periodontal ligament cells (PDLC), the main contributor to periodontal tissue regeneration, to nanoparticles of hydroxyapatite. The objective of this study was to investigate the possible effects of nanophase powder of hydroxyapatite on proliferation of periodontal ligament cells. Using a sol-gel method, the nanophase hydroxyapatite powders were fabricated. These powders were proved to comprise nanoparticles by transmission electron microscope examination. The primary periodontal ligament cells were cultured on dense particle hydroxyapatite and nanometer particle hydroxyapatite. The effects on proliferation of periodontal ligament cells on dense and nanoparticle hydroxyapatite were examined in vitro using a methyl thiazolil tetracolium (MTT) test. The intercellular effects were studied with scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive X-ray (EDX). In addition, the influence of the two materials on osteogenic differentiation was determined through measurement of alkaline phosphatase activity and flow cytometry. About 2, 3, and 4 days after treatment with nanoparticles of hydroxyapatite, the proliferation activity of the PDLC increased significantly compared with those proliferating on dense hydroxyapatite and of control PDLC, but no significant difference was found between the PDLC proliferation on dense hydroxyapatite and the control PDLCs. After 3 and 5 days' incubation with nanoparticles of hydroxyapatite, alkaline phosphatase activity was significantly increased as compared to PDLCs incubated with dense hydroxyapatite and control PDLCs. Intracellular engulfment was found in the cultured cells with nanophase hydroxyapatite under electron microscopy. The results suggest that nanophase hydroxyapatite can promote proliferation and osteogenic differentiation of periodontal ligament cells and further that it may be used as a bioresorbable agent in osseous restoration. PMID:17143736

  17. Size dependence and field-induced magnetic anisotropy of granular nanophases. Application to microwave isolation

    NASA Astrophysics Data System (ADS)

    Mallgol, Stphane; Brosseau, Christian; Qufflec, Patrick; Konn, Anne-Marie

    2004-05-01

    The induced anisotropy of magnetized nanocomposite samples is investigated through the experimental determination of a non-zero off-diagonal effective permeability tensor term ?. The samples are constituted of ferrimagnetic (?-Fe 2O 3) or ferromagnetic (Ni) grains uniformly dispersed in a matrix composed of ZnO particles. We characterize the volume fraction and grain size dependences of ?. Then, we show that the induced anisotropy of the nanophases can be exploited to realize a microwave resonance isolator.

  18. Use of ferric sulfate: acid media for the desulfurization of model compounds of coal. [Dibenzothiophene, diphenyl sulfide, di-n-butyl sulfide

    SciTech Connect

    Clary, L.R.; Vermeulen, T.; Lynn, S.

    1980-12-01

    The objective of this work has been to investigate the ability of ferric sulfate-acid leach systems to oxidize the sulfur in model compounds of coal. Ferric iron-acid leach systems have been shown to be quite effective at removal of inorganic sulfur in coal. In this study, the oxidative effect of ferric iron in acid-leach systems was studied using dibenzothiophene, diphenyl sulfide, and di-n-butyl sulfide as models of organic sulfur groups in coal. Nitrogen and oxygen, as well as various transition metal catalysts and oxidants, were utilized in this investigation. Dibenzothiophene was found to be quite refractory to oxidation, except in the case where metavanadate was added, where it appears that 40% oxidation to sulfone could have occurred per hour at 150/sup 0/C and mild oxygen pressure. Diphenyl sulfide was selectively oxidized to sulfoxide and sulfone in an iron and oxygen system. Approximately 15% conversion to sulfone occurred per hour under these conditions. Some of the di-n-butyl sulfide was cracked to 1-butene and 1-butanethiol under similar conditions. Zinc chloride and ferric iron were used at 200/sup 0/C in an attempt to desulfonate dibenzothiophene sulfone, diphenyl sulfone, and di-n-butyl sulfone. Di-n-butyl sulfone was completely desulfurized on one hour and fragmented to oxidized parafins, while dibenzothiophene sulfone and diphenyl sulfone were unaffected. These results suggest that an iron-acid leach process could only selectively oxidize aryl sulfides under mild conditions, representing only 20% of the organic sulfur in coal (8% of the total sulfur). Removal through desulfonation once selective sulfur oxidation had occurred was only demonstrated for alkyl sulfones, with severe oxidation of the fragmented paraffins also occurring in one hour.

  19. Bacterial Formation of As(V) and As(III) Ferric Oxyhydroxides in Acid Mine Drainage.

    NASA Astrophysics Data System (ADS)

    Morin, G.; Juillot, F.; Lebrun, S.; Casiot, C.; Elbaz-Poulichet, F.; Bruneel, O.; Personne, J.; Leblanc, M.; Ildefonse, P.; Calas, G.

    2002-12-01

    The oxidation of dissolved Fe(II) which is often promoted by acidophilic bacteria in acid mine drainage (AMD) and some hot springs, leads to the precipitation of Fe(III) oxy-hydroxides which incorporate toxic elements within their structure or adsorb them at their surface, thus limiting their mobility. In such complex natural systems, synchrotron-based techniques as X-ray absorption spectroscopy offer the opportunity to monitor surface/solution interactions as well as redox changes affecting the mobility and toxicity of trace elements as arsenic. Spatial and seasonal variations of the (bio-) oxidation of Fe(II) and As(III), and the subsequent precipitation of As-Fe gels, were followed by XANES, XRD, and SEM along the Carnouls AMD (Gard, France). Chemical and mineralogical data collected on sediments, stromatolite, and bioassay samples showed that some indigenous bacteria living in the As-rich Carnouls water ([As] = up to 350 mg.l-1) play an important role in the nature and composition of the solid phases that sequester arsenic at the site. The formation of nano-crystalline and amorphous As(III) ferric oxy-hydroxides has been related to the presence of bacteria able to oxidize Fe(II) but not As(III), which are only present in winter in the upstream area. A rare ferric arsenite sulfate oxy-hydroxide mineral was discovered in this context. Other types of bacteria, occurring in the downstream area whatever the season, are able to catalyze As(III) to As(V) oxidation and, provided that enough Fe(II) oxidizes, promote the formation of amorphous As(V) rich ferric oxy-hydroxides. These bacterially mediated reactions significantly reduce the concentration of dissolved As(III), which is more toxic and mobile than As(V), and might thus be helpful for designing As-removal processes. This work was supported by the French PEVS and ACI Ecologie Quantitative Programs and the PIRAMID EC program. ?Deceased, 26 October 1999 Juillot F., Ildefonse Ph., Morin G., Calas G., De Kersabiec A.M. and Benedetti M. Applied Geochemistry 8, 1031-1048 (1999). Morin G., Lecocq D., Juillot F., Ildefonse Ph., Calas Bull. Soc. Gol. Fr. 173, 281-291 (2002). Morin G., Juillot F., Casiot C., Bruneel O., Personn J-C., Elbaz-Poulichet F., Leblanc M., Ildefonse P. and Calas G. Environ. Sci. Technol (in review.)

  20. Thermochemical Investigations of Nano-phase Ammonia Borane: Effect of Higher Loading

    NASA Astrophysics Data System (ADS)

    Karkamkar, Abhi; Stowe, Ashley; Autrey, Tom

    2009-03-01

    Chemical hydrogen storage materials that release H2 by thermolysis without generating CO2 offer an attractive option. The ammonia borane is an attractive compound containing more than 18 wt% hydrogen. However, the kinetics of hydrogen release in not favorable in bulk materials where H2 is released at 114 ^oC. We recently reported use of SBA-15 as scaffold material to form a nanophase ammonia borane species which liberated H2 at significantly lower temperatures. Hydrogen formation from bulk AB is slightly exothermic (-5 kcal/mol). The reaction enthalpy (?H) for release of H2 from AB adsorbed into SBA-15 (1:1 w/w) was determined to be nearly thermoneutral---dramatically lower than the bulk material. A near thermoneutral reaction suggests that there would be less restrictive heat management issues, greater thermal stability and potentially a lower energy input requirement for regeneration of AB. One drawback which results for nano-phase AB is that while the hydrogen release properties are enhanced, the gravimetric hydrogen density is reduced by a 50% for the 1 to 1 by mass ratio material. We here report on our efforts to increase the gravimetric hydrogen density of nano-phase AB by developing higher loading conditions of AB adsorbed into mesoporous silica (MCM-41).

  1. 21 CFR 73.1025 - Ferric ammonium citrate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Ferric ammonium citrate. 73.1025 Section 73.1025 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF... material. (3) When the sutures are used for the purposes specified in their labeling, there is no...

  2. 21 CFR 73.1025 - Ferric ammonium citrate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Ferric ammonium citrate. 73.1025 Section 73.1025 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF... material. (3) When the sutures are used for the purposes specified in their labeling, there is no...

  3. 21 CFR 73.1025 - Ferric ammonium citrate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Ferric ammonium citrate. 73.1025 Section 73.1025 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF... material. (3) When the sutures are used for the purposes specified in their labeling, there is no...

  4. 21 CFR 73.1025 - Ferric ammonium citrate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Ferric ammonium citrate. 73.1025 Section 73.1025 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF... material. (3) When the sutures are used for the purposes specified in their labeling, there is no...

  5. The Effect of Ferric Chloride on Superficial Bleeding

    PubMed Central

    Nouri, Saeed; Sharif, Mohammad Reza; Sahba, Sare

    2015-01-01

    Background: Controlling superficial bleeding, despite all the progress in surgical science, is still a challenge in some settings. Objectives: This study assesses the hemostatic effects of ferric chloride and compares it with the standard method (suturing technique) to control superficial bleeding. Materials and Methods: In this animal model study, 60 male Wistar rats were used. An incision, 2 cm long and 0.5 cm deep was made on rat skin and the hemostasis time was recorded using ferric chloride at different concentrations (5%, 10%, 15%, 25%, and 50%) and then using a control (i.e. control of bleeding by suturing). The skin tissue was examined for pathological changes. Finally, the obtained data were entered into SPSS (ver. 16) and analyzed using Kruskal-Wallis test, Mann-Whitney, Kolmogorov-Smirnov, and Wilcoxon signed ranks test. Results: The hemostasis time for the ferric chloride concentration group was significantly less than for the control group (P < 0.001). Conclusions: Ferric chloride may be an effective hemostatic agent to control superficial bleeding in rats. PMID:25825694

  6. 21 CFR 184.1296 - Ferric ammonium citrate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... citrate (iron (III) ammonium citrate) is prepared by the reaction of ferric hydroxide with citric acid... 18.5 percent iron, approximately 9 percent ammonia, and 65 percent citric acid and occurs as reddish... composed of 14.5 to 16 percent iron, approximately 7.5 percent ammonia, and 75 percent citric acid...

  7. 21 CFR 184.1296 - Ferric ammonium citrate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... citrate (iron (III) ammonium citrate) is prepared by the reaction of ferric hydroxide with citric acid... 18.5 percent iron, approximately 9 percent ammonia, and 65 percent citric acid and occurs as reddish... composed of 14.5 to 16 percent iron, approximately 7.5 percent ammonia, and 75 percent citric acid...

  8. CU(II): catalyzed hydrazine reduction of ferric nitrate

    SciTech Connect

    Karraker, D.G.

    1981-11-01

    A method is described for producing ferrous nitrate solutions by the cupric ion-catalyzed reduction of ferric nitrate with hydrazine. The reaction is complete in about 1.5 hours at 40/sup 0/C. Hydrazoic acid is also produced in substantial quantities as a reaction byproduct.

  9. Complex-formation and reduction of ferric iron by 2-oxo-4-thiomethylbutyric acid, and the production of hydroxyl radicals.

    PubMed Central

    Winston, G W; Eibschutz, O M; Strekas, T; Cederbaum, A I

    1986-01-01

    2-Oxo-4-thiomethylbutyric acid (OMBA) is a widely used oxygen-radical-scavenging agent and has been used for the detection of .OH-like species in a variety of systems. This scavenger reacts with other radicals and is therefore not specific for .OH. Since iron is required in most systems for the generation of OH-like species, studies were carried out to investigate the possible interaction of OMBA with iron. Fe3+ reacted with OMBA to produce complexes that gave rise to discrete spectra. Intense purple complexes, with broad absorbance maxima of 525-550 nm, were found at OMBA/Fe3+ ratios of up to 1:1, whereas red complexes with a prominent shoulder between 440 and 480 nm were found at higher OMBA/Fe3+ ratios. OMBA caused reduction of ferric iron to the ferrous state, as detected with 2,2'-bipyridyl as the indicator. This reduction occurs in the dark, can be photo-accelerated especially by light with wavelengths near the absorbance maximum of the respective complexes, and is increased as the OMBA/Fe3+ ratio is elevated. The presence of phosphate buffer quenches the purple and red ferric-ion-OMBA complexes and lowers the rate of reduction of Fe3+ by OMBA about 10-fold. The resulting ferrous-ion-OMBA-phosphate complex is very stable against autoxidation. Both the ferrous-ion-OMBA and ferric-ion-OMBA complexes reacted with H2O2, with the subsequent production of ethylene gas from OMBA. The interaction with H2O2 resulted in discrete spectral changes of both the ferrous-ion-OMBA and ferric-ion-OMBA complexes. The ferrous-ion-OMBA/H2O2 or ferric-ion-OMBA/H2O2 system appeared to produce .OH free radicals via a Fenton-type of reaction since ethylene production was inhibited by competitive OH scavengers. Ferrous-ion-OMBA complex reacted with H2O2 not only to produce ethylene from the OMBA, but also to promote the oxidation of another scavenger, ethanol. The ability of OMBA to chelate iron, to promote reduction of ferric iron and to react with H2O2 to produce potent oxidizing radicals may play a role in the lack of specificity of OMBA as a scavenger of oxygen radicals. PMID:3741403

  10. 40 CFR 415.380 - Applicability; description of the ferric chloride production subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... ferric chloride production subcategory. 415.380 Section 415.380 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Ferric Chloride Production Subcategory 415.380 Applicability; description of the ferric chloride production subcategory. The provisions of this subpart are applicable to discharges and to...

  11. 40 CFR 415.380 - Applicability; description of the ferric chloride production subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... ferric chloride production subcategory. 415.380 Section 415.380 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Ferric Chloride Production Subcategory 415.380 Applicability; description of the ferric chloride production subcategory. The provisions of this subpart are applicable to discharges and to...

  12. 40 CFR 180.1191 - Ferric phosphate; 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 Ferric phosphate; exemption from the... Exemptions From Tolerances § 180.1191 Ferric phosphate; exemption from the requirement of a tolerance. An..., ferric phosphate (FePO4, CAS No. 11045-86-0) in or on all food commodities....

  13. 40 CFR 180.1191 - Ferric phosphate; 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 Ferric phosphate; exemption from the... Exemptions From Tolerances § 180.1191 Ferric phosphate; exemption from the requirement of a tolerance. An..., ferric phosphate (FePO4, CAS No. 11045-86-0) in or on all food commodities....

  14. 40 CFR 180.1191 - Ferric phosphate; 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 Ferric phosphate; exemption from the... Exemptions From Tolerances § 180.1191 Ferric phosphate; exemption from the requirement of a tolerance. An..., ferric phosphate (FePO4, CAS No. 11045-86-0) in or on all food commodities....

  15. 40 CFR 180.1191 - Ferric phosphate; 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 Ferric phosphate; exemption from the... Exemptions From Tolerances § 180.1191 Ferric phosphate; exemption from the requirement of a tolerance. An..., ferric phosphate (FePO4, CAS No. 11045-86-0) in or on all food commodities....

  16. 40 CFR 180.1191 - Ferric phosphate; 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 Ferric phosphate; exemption from the... Exemptions From Tolerances § 180.1191 Ferric phosphate; exemption from the requirement of a tolerance. An..., ferric phosphate (FePO4, CAS No. 11045-86-0) in or on all food commodities....

  17. 40 CFR 415.380 - Applicability; description of the ferric chloride production subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... ferric chloride production subcategory. 415.380 Section 415.380 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Ferric Chloride Production Subcategory 415.380 Applicability; description of the ferric chloride production subcategory. The provisions of this subpart are applicable to discharges and to...

  18. 40 CFR 415.380 - Applicability; description of the ferric chloride production subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... ferric chloride production subcategory. 415.380 Section 415.380 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Ferric Chloride Production Subcategory 415.380 Applicability; description of the ferric chloride production subcategory. The provisions of this subpart are applicable to discharges and to...

  19. 40 CFR 415.380 - Applicability; description of the ferric chloride production subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... ferric chloride production subcategory. 415.380 Section 415.380 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Ferric Chloride Production Subcategory 415.380 Applicability; description of the ferric chloride production subcategory. The provisions of this subpart are applicable to discharges and to...

  20. Optimization of ferric hydroxide coprecipitation process for selenium removal from petroleum refinery stripped four water

    SciTech Connect

    Gerhardt, M.B.; Marrs, D.R.; Roehl, R.

    1996-12-31

    Iron coprecipitation was used in bench-scale tests to remove selenium from stripped sour water generated by two petroleum refineries. Chlorine dioxide and hydrogen peroxide were found to convert selenocyanate in the stripped sour water to selenite, which can be removed by iron coprecipitation. An iodometric titration procedure was developed to determine the required oxidant dose. Iron coprecipitation reduced selenium concentrations by 40 to 99 percent in stripped sour water after chlorine dioxide pretreatment Removal was less effective with hydrogen peroxide as the oxidant: total selenium concentrations were reduced by 28 to 92 percent in stripped sour water after hydrogen peroxide pretreatment. Highest removals were obtained at the highest oxidant and iron doses. Sludges produced in coprecipitation tests were hazardous under California regulations. Ozone oxidized selenocyanate but prevented ferric hydroxide precipitation or coagulation. Air was ineffective at selenocyanate oxidation. Repeatedly contacting iron hydroxide with stripped sour water pretreated with hydrogen peroxide, in a simulation of a countercurrent adsorption process, increased the selenium adsorbed on the solids from 32 to 147 pg selenium per mg of iron, but some of the adsorbed selenite was oxidized to selenate and desorbed back into solution.

  1. Ferric sulfate as pulpotomy agent in primary teeth: twenty month clinical follow-up.

    PubMed

    Ibricevic, H; al-Jame, Q

    2000-01-01

    Seventy primary molar teeth, carious exposed, symptom free, without any sign of root resorption in children aged from 3 to 6 years (main age 4.3 yr) were treated with conventional pulpotomy procedures. Ferric sulfate 15.5% solution (applied for 15 second for 35 teeth) and formocresol solution (five minute procedure of Buckley's formula for next 35 teeth) have been used as pulpotomy agents. In both groups, pulp stumps were covered with zinc-oxide eugenol paste. Permanent restorations were stainless steel crowns. Clinical check up was every three-months and radiographic follow-up time was six and twenty months after treatment. Our results within this period revealed 100% clinical success rate in both groups. Radiographic success rate was in both groups 97.2%, while in 2.8% cases has shown internal root resorption. On the basis of these results, we can recommend ferric sulfate as a pulpotomy agent in primary teeth in substitution for formocresol at the moment. PMID:11314410

  2. Ferric saponite and serpentine in the nakhlite martian meteorites

    NASA Astrophysics Data System (ADS)

    Hicks, L. J.; Bridges, J. C.; Gurman, S. J.

    2014-07-01

    Transmission electron microscopy and Fe-K X-ray absorption spectroscopy have been used to determine structure and ferric content of the secondary phase mineral assemblages in the nakhlite martian meteorites, NWA 998, Lafayette, Nakhla, GV, Y 000593, Y 000749, MIL 03346, NWA 817, and NWA 5790. The secondary phases are a rapidly cooled, metastable assemblage that has preserved Mg# and Ca fractionation related to distance from the fluid source, for most of the nakhlites, though one, NWA 5790, appears not to have experienced a fluid pathway. All nine nakhlite samples have also been analysed with scanning electron microscopy, electron probe micro analysis, Bright Field high-resolution transmission electron microscopy (HRTEM) and selected area electron diffraction. By measuring the energy position of the Fe-K XANES 1s ? 3d pre-edge transition centroid we calculate the ferric content of the minerals within the nakhlite meteorites. The crystalline phyllosilicates and amorphous silicate of the hydrothermal deposits filling the olivine fractures are found to have variable Fe3+/?Fe values ranging from 0.4 to 0.9. In Lafayette, the central silicate gel parts of the veins are more ferric than the phyllosilicates around it, showing that the fluid became increasingly oxidised. The mesostasis of Lafayette and NWA 817 also have phyllosilicate, which have a higher ferric content than the olivine fracture deposits, with Fe3+/?Fe values of up to 1.0. Further study, via TEM analyses, reveal the Lafayette and NWA 817 olivine phyllosilicates to have 2:1 T-O-T lattice structure with a the d001-spacing of 0.96 nm, whereas the Lafayette mesostasis phyllosilicates have 1:1 T-O structure with d001-spacings of 0.7 nm. Based on our analyses, the phyllosilicate found within the Lafayette olivine fractures is trioctahedral ferric saponite (Ca0.2K0.1)?0.3(Mg2.6Fe2+1.3Fe3+1.7Mn0.1)?5.7[(Si6.7AlIV0.9Fe3+0.4)?8.0O20](OH)4nH2O, and that found in the mesostasis fractures is an Fe-serpentine (Ca0.1Mg0.7Fe3+1.0AlVI0.4)?2.2[Si2O5]OH4, with a ferric gel of similar composition in Lafayette and found as fracture fills throughout the other nakhlites.

  3. Ferric-Thiolate Bond Dissociation Studied with Electronic Structure Calculations.

    PubMed

    Arantes, Guilherme Menegon; Field, Martin J

    2015-10-01

    The stability and reactivity of iron-sulfur clusters are fundamental properties for the biological function of these prosthetic groups. Here, we investigate the ferric-thiolate bond dissociation of model iron-sulfur tetrahedral complexes with high-level ab initio multiconfigurational electronic structure calculations. We find that the reaction mechanism is homolytic with a spin-crossing from the sextet state in the reactant to quartet state in the product. We also compare several density functionals and semiempirical configuration interaction with the high-level ab initio results to find an accurate but computationally more efficient method to describe the reaction. The functionals M06 and those based on the OPTX exchange functional show the best performance and may reasonably describe the various electron correlation effects involved in ferric-thiolate bond dissociation. PMID:26351881

  4. Impact of Iron-Reducing Bacteria on Metals and Radionuclides Adsorbed to Humic-Coated Iron(III) Oxides

    SciTech Connect

    Burgos, W. D.

    2005-02-01

    This is the final report for Grant No. DEFGO2-98ER62691 submitted to the DOE NABR Program. This research has focused on (1) the role of natural organic matter (NOM), quinines, and complexants in enhancing the biological reduction of solid-phase crystalline ferric oxides, (2) the effect of heavy metals (specifically zinc) and NOM on ferric oxide bioreduction, (3) the sorption of Me(II) [Cu(II), Fe(II), Mn(II) and Zn(II)] to ferric oxides and subsequent Me(II)-promoted phase transformations of the ferric oxides, and (4) the development of reaction-based biogeochemical models to numerically simulate our experimental results.

  5. Paracoccidioides spp. ferrous and ferric iron assimilation pathways

    PubMed Central

    Bailo, Elisa Flvia L. C.; Lima, Patrcia de Sousa; Silva-Bailo, Mirelle G.; Bailo, Alexandre M.; Fernandes, Gabriel da Rocha; Kosman, Daniel J.; Soares, Clia Maria de Almeida

    2015-01-01

    Iron is an essential micronutrient for almost all organisms, including fungi. Usually, fungi can uptake iron through receptor-mediated internalization of a siderophore or heme, and/or reductive iron assimilation (RIA). Traditionally, the RIA pathway consists of ferric reductases (Fres), ferroxidase (Fet3) and a high-affinity iron permease (Ftr1). Paracoccidioides spp. genomes do not present an Ftr1 homolog. However, this fungus expresses zinc regulated transporter homologs (Zrts), members of the ZIP family of membrane transporters that are able in some organisms to transport zinc and iron. A 2,3,5-triphenyltetrazolium chloride (TTC)-overlay assay indicates that both Pb01 and Pb18 express a ferric reductase activity; however, 59Fe uptake assays indicate that only in Pb18 is this activity coupled to a reductase-dependent iron uptake pathway. In addition, Zrts are up-regulated in iron deprivation, as indicated by RNAseq and qRT-PCR using Pb01 transcripts. RNAseq strategy also demonstrated that transcripts related to siderophore uptake and biosynthesis are up-regulated in iron-deprived condition. The data suggest that the fungus could use both a non-classical RIA, comprising ferric reductases and Fe/Zn permeases (Zrts), and siderophore uptake pathways under iron-limited conditions. The study of iron metabolism reveals novel surface molecules that could function as accessible targets for drugs to block iron uptake and, consequently, inhibit pathogen's proliferation. PMID:26441843

  6. Ferric chloride-induced murine carotid arterial injury: A model of redox pathology?

    PubMed Central

    Li, Wei; McIntyre, Thomas M.; Silverstein, Roy L.

    2013-01-01

    Ferric chloride (FeCl3) induced vascular injury is a widely used model of occlusive thrombosis that reports platelet activation in the context of an aseptic closed vascular system. This model is based on redox-induced endothelial cell injury, which is simple and sensitive to both anticoagulant and anti-platelets drugs. The time required for platelet aggregation to occlude blood flow gives a quantitative measure of vascular damage that is pathologically relevant to thrombotic disease. We have refined the traditional FeCl3-induced carotid artery model making the data highly reproducible with lower variation. This paper will describe our artifices and report the role of varying the oxidative damage by varying FeCl3 concentrations and exposure. To explore a maximum difference between experimental groups, adjustment of the selected FeCl3 dose and exposure duration may be necessary. PMID:25101237

  7. Factors influencing the mechanism of surfactant catalyzed reaction of vitamin C-ferric chloride hexahydrate system

    NASA Astrophysics Data System (ADS)

    Farrukh, Muhammad Akhyar; Kauser, Robina; Adnan, Rohana

    2013-09-01

    The kinetics of vitamin C by ferric chloride hexahydrate has been investigated in the aqueous ethanol solution of basic surfactant viz. octadecylamine (ODA) under pseudo-first order conditions. The critical micelle concentration (CMC) of surfactant was determined by surface tension measurement. The effect of pH (2.5-4.5) and temperature (15-35C) in the presence and absence of surfactant were investigated. Activation parameters, ? E a, ? H #, ? S #, ? G ?, for the reaction were calculated by using Arrhenius and Eyring plot. Surface excess concentration (?max), minimum area per surfactant molecule ( A min), average area occupied by each molecule of surfactant ( a), surface pressure at the CMC (?max), Gibb's energy of micellization (? G M), Gibb's energy of adsorption (? G ad), were calculated. It was found that the reaction in the presence of surfactant showed faster oxidation rate than the aqueous ethanol solution. Reaction mechanism has been deduced in the presence and absence of surfactant.

  8. A new route to the preparation of nanophase composites via layered double hydroxides

    SciTech Connect

    Isupov, V.P.; Tarasov, K.A.; Mitrofanova, R.P.; Chupakhina, L.E.

    1997-09-01

    A promising route to the preparation of nanophase composites with fine particles of transition metals via layered double hydroxides has been shown on the derivatives of Li-Al double hydroxide, LADH-X, where interlayer X anions are complexes of transition metals. Thermal decomposition of such materials in vacuum or an inert gas leads to dehydration and dehydroxylation of the hydroxide matrix and to the collapse red/ox process of the complex anion. The latter results in the carbonization of the samples and in the appearance of nanoscale (20--500 {angstrom}) metal particles.

  9. Ferric citrate controls phosphorus and delivers iron in patients on dialysis.

    PubMed

    Lewis, Julia B; Sika, Mohammed; Koury, Mark J; Chuang, Peale; Schulman, Gerald; Smith, Mark T; Whittier, Frederick C; Linfert, Douglas R; Galphin, Claude M; Athreya, Balaji P; Nossuli, A Kaldun Kaldun; Chang, Ingrid J; Blumenthal, Samuel S; Manley, John; Zeig, Steven; Kant, Kotagal S; Olivero, Juan Jose; Greene, Tom; Dwyer, Jamie P

    2015-02-01

    Patients on dialysis require phosphorus binders to prevent hyperphosphatemia and are iron deficient. We studied ferric citrate as a phosphorus binder and iron source. In this sequential, randomized trial, 441 subjects on dialysis were randomized to ferric citrate or active control in a 52-week active control period followed by a 4-week placebo control period, in which subjects on ferric citrate who completed the active control period were rerandomized to ferric citrate or placebo. The primary analysis compared the mean change in phosphorus between ferric citrate and placebo during the placebo control period. A sequential gatekeeping strategy controlled study-wise type 1 error for serum ferritin, transferrin saturation, and intravenous iron and erythropoietin-stimulating agent usage as prespecified secondary outcomes in the active control period. Ferric citrate controlled phosphorus compared with placebo, with a mean treatment difference of -2.20.2 mg/dl (meanSEM) (P<0.001). Active control period phosphorus was similar between ferric citrate and active control, with comparable safety profiles. Subjects on ferric citrate achieved higher mean iron parameters (ferritin=899488 ng/ml [meanSD]; transferrin saturation=39%17%) versus subjects on active control (ferritin=628367 ng/ml [meanSD]; transferrin saturation=30%12%; P<0.001 for both). Subjects on ferric citrate received less intravenous elemental iron (median=12.95 mg/wk ferric citrate; 26.88 mg/wk active control; P<0.001) and less erythropoietin-stimulating agent (median epoetin-equivalent units per week: 5306 units/wk ferric citrate; 6951 units/wk active control; P=0.04). Hemoglobin levels were statistically higher on ferric citrate. Thus, ferric citrate is an efficacious and safe phosphate binder that increases iron stores and reduces intravenous iron and erythropoietin-stimulating agent use while maintaining hemoglobin. PMID:25060056

  10. Ferric Citrate Controls Phosphorus and Delivers Iron in Patients on Dialysis

    PubMed Central

    Sika, Mohammed; Koury, Mark J.; Chuang, Peale; Schulman, Gerald; Smith, Mark T.; Whittier, Frederick C.; Linfert, Douglas R.; Galphin, Claude M.; Athreya, Balaji P.; Nossuli, A. Kaldun Kaldun; Chang, Ingrid J.; Blumenthal, Samuel S.; Manley, John; Zeig, Steven; Kant, Kotagal S.; Olivero, Juan Jose; Greene, Tom; Dwyer, Jamie P.

    2015-01-01

    Patients on dialysis require phosphorus binders to prevent hyperphosphatemia and are iron deficient. We studied ferric citrate as a phosphorus binder and iron source. In this sequential, randomized trial, 441 subjects on dialysis were randomized to ferric citrate or active control in a 52-week active control period followed by a 4-week placebo control period, in which subjects on ferric citrate who completed the active control period were rerandomized to ferric citrate or placebo. The primary analysis compared the mean change in phosphorus between ferric citrate and placebo during the placebo control period. A sequential gatekeeping strategy controlled study-wise type 1 error for serum ferritin, transferrin saturation, and intravenous iron and erythropoietin-stimulating agent usage as prespecified secondary outcomes in the active control period. Ferric citrate controlled phosphorus compared with placebo, with a mean treatment difference of ?2.20.2 mg/dl (meanSEM) (P<0.001). Active control period phosphorus was similar between ferric citrate and active control, with comparable safety profiles. Subjects on ferric citrate achieved higher mean iron parameters (ferritin=899488 ng/ml [meanSD]; transferrin saturation=39%17%) versus subjects on active control (ferritin=628367 ng/ml [meanSD]; transferrin saturation=30%12%; P<0.001 for both). Subjects on ferric citrate received less intravenous elemental iron (median=12.95 mg/wk ferric citrate; 26.88 mg/wk active control; P<0.001) and less erythropoietin-stimulating agent (median epoetin-equivalent units per week: 5306 units/wk ferric citrate; 6951 units/wk active control; P=0.04). Hemoglobin levels were statistically higher on ferric citrate. Thus, ferric citrate is an efficacious and safe phosphate binder that increases iron stores and reduces intravenous iron and erythropoietin-stimulating agent use while maintaining hemoglobin. PMID:25060056

  11. The nanophase iron mineral(s) in Mars soil

    NASA Technical Reports Server (NTRS)

    Banin, A.; Ben-Shlomo, T.; Margulies, L.; Blake, D. F.; Gehring, A. U.

    1992-01-01

    Iron-enriched smectites have been suggested as important mineral compounds of the Martian soil. They were shown to comply with the chemical analysis of the Martian soil, to simulate many of the findings of the Viking Labeled Release Experiments on Mars, to have spectral reflectance in the VIS-NIR strongly resembling the bright regions on Mars. The analogy with Mars soil is based, in a number of aspects, on the nature and behavior of the iron oxides and oxyhydroxides deposited on the surface of the clay particles. A summary of the properties of these iron phases and some recent findings are presented. Their potential relevance to Mars surface processes is discussed.

  12. The role of the crystallization temperature on the nanophase structure evolution of poly[(R)-3-hydroxybutyrate].

    PubMed

    Righetti, Maria Cristina; Tombari, Elpidio; Di Lorenzo, Maria Laura

    2013-10-10

    The nanophase structure of semicrystalline polymers, which determines the mechanical, thermal, and gas permeability behavior, can be quantified by thermal methods. A detailed investigation of the nanophase structure of poly[(R)-3-hydroxybutyrate] (PHB) was performed under conditions of isothermal, quasi-isothermal, and nonisothermal crystallizations. The experimental analyses revealed that the establishment of the nanophase rigid amorphous fraction (RAF) in PHB depends on the temperature at which crystallization occurs. The RAF grows in parallel with the crystal phase during quasi-isothermal crystallization at 30 C, whereas during nonisothermal crystallization at higher temperatures, RAF starts to develop at 70 C, in correspondence with the final stages of the crystallization process. The influence of crystallization temperature on the nanophase structure was rationalized taking into account the effect of the mobility of the entangled chain segments during the phase transition. The melting behavior was found to change after isothermal crystallization at 70 C, revealing that complete RAF mobilization is achieved approximately at this temperature. The temperature of 70 C could be the limit for the formation and the disappearance of rigid amorphous fraction in the PHB analyzed in the present study. PMID:24020615

  13. Laboratory Simulation of Space Weathering: ESR Measurements of Nanophase Metallic Iron in Laser-irradiated Olivine and Pyroxene Samples

    NASA Technical Reports Server (NTRS)

    Kurahashi, E.; Yamanaka, C.; Nakamura, K.; Sasaki, S.

    2003-01-01

    S-type asteroids are believed to be parent bodies of ordinary chondrites. Although both S-type asteroids and ordinary chondrites contain the same mineral assemblage, mainly olivine and pyroxene, the reflectance spectra of the asteroids exhibit more overall depletion (darkening) and reddening, and more weakening of absorption bands relative to the meteorites. This spectral mismatch is explained by space weathering process, where high-velocity dust particle impacts should change the optical properties of the uppermost regolith surface of asteroids. In order to simulate the space weathering, we irradiated nanosecond pulse laser beam onto pellet samples of olivine (8.97wt% FeO) and pyroxene (enstatite: 9.88wt% FeO, hypersthene: 16.70wt%). We got spectral changes in our samples similar to that by space weathering on asteroids and confirmed nanophase alpha-metallic iron particles, which were theoretically predicted, not only on olivine but also on pyroxene samples by Transmission Electron Microscopy (TEM). Nanophase metallic iron particles were widely scattered throughout the amorphous rims developed along the olivine grains, whereas they were embedded in aggregates of amorphous in enstatite samples. Recently, we also measured laser-irradiated samples by ESR (Electron Spin Resonance). Strong ESR signals, characteristic to nanophase iron particles, are observed on irradiated olivine samples. In this paper, we report the quantities of nanophase metallic iron particles in pyroxene samples by ESR observations in addition to olivine samples.

  14. Reducing bacteria and macrophage density on nanophase hydroxyapatite coated onto titanium surfaces without releasing pharmaceutical agents.

    PubMed

    Bhardwaj, Garima; Yazici, Hilal; Webster, Thomas J

    2015-05-14

    Reducing bacterial density on titanium implant surfaces has been a major concern because of the increasing number of nosocomial infections. Controlling the inflammatory response post implantation has also been an important issue for medical devices due to the detrimental effects of chronic inflammation on device performance. It has recently been demonstrated that manipulating medical device surface properties including chemistry, roughness and wettability can control both infection and inflammation. Here, we synthesized nanophase (that is, materials with one dimension in the nanoscale) hydroxyapatite coatings on titanium to reduce bacterial adhesion and inflammatory responses (as measured by macrophage functions) and compared such results to bare titanium and plasma sprayed hydroxyapatite titanium coated surfaces used clinically today. This approach is a pharmaceutical-free approach to inhibit infection and inflammation due to the detrimental side effects of any drug released in the body. Here, nanophase hydroxyapatite was synthesized in sizes ranging from 110-170 nm and was subsequently coated onto titanium samples using electrophoretic deposition. Results indicated that smaller nanoscale hydroxyapatite features on titanium surfaces alone decreased bacterial attachment in the presence of gram negative (P. aeruginosa), gram positive (S. aureus) and ampicillin resistant gram-negative (E. coli) bacteria as well as were able to control inflammatory responses; properties which should lead to their further investigation for improved medical applications. PMID:25876524

  15. Heavy metal phosphate nanophases in silica: influence of radiolysis probed via f-electron state properties

    SciTech Connect

    Beitz, James V. . E-mail: beitz@anl.gov; Williams, C.W.; Hong, K.-S.; Liu, G.K.

    2005-02-15

    We have assessed the feasibility of carrying out time- and wavelength-resolved laser-induced fluorescence measurements of radiation damage in glassy silica. The consequences of alpha decay of Es-253 in LaPO{sub 4} nanophases embedded in silica were probed based on excitation of 5f states of Cm{sup 3+}, Bk{sup 3+}, and Es{sup 3+} ions. The recorded emission spectra and luminescence decays showed that alpha decay of Es-253 ejected Bk-249 decay daughter ions into the surrounding silica and created radiation damage within the LaPO{sub 4} nanophases. This conclusion is consistent with predictions of an ion transport code commonly used to model ion implantation. Luminescence from the {sup 6}D{sub 7/2} state of Cm{sup 3+}was used as an internal standard. Ion-ion energy transfer dominated the dynamics of the observed emitting 5f states and strongly influenced the intensity of observed spectra. In appropriate sample materials, laser-induced fluorescence provides a powerful method for fundamental investigation of alpha-induced radiation damage in silica.

  16. Reducing bacteria and macrophage density on nanophase hydroxyapatite coated onto titanium surfaces without releasing pharmaceutical agents

    NASA Astrophysics Data System (ADS)

    Bhardwaj, Garima; Yazici, Hilal; Webster, Thomas J.

    2015-04-01

    Reducing bacterial density on titanium implant surfaces has been a major concern because of the increasing number of nosocomial infections. Controlling the inflammatory response post implantation has also been an important issue for medical devices due to the detrimental effects of chronic inflammation on device performance. It has recently been demonstrated that manipulating medical device surface properties including chemistry, roughness and wettability can control both infection and inflammation. Here, we synthesized nanophase (that is, materials with one dimension in the nanoscale) hydroxyapatite coatings on titanium to reduce bacterial adhesion and inflammatory responses (as measured by macrophage functions) and compared such results to bare titanium and plasma sprayed hydroxyapatite titanium coated surfaces used clinically today. This approach is a pharmaceutical-free approach to inhibit infection and inflammation due to the detrimental side effects of any drug released in the body. Here, nanophase hydroxyapatite was synthesized in sizes ranging from 110-170 nm and was subsequently coated onto titanium samples using electrophoretic deposition. Results indicated that smaller nanoscale hydroxyapatite features on titanium surfaces alone decreased bacterial attachment in the presence of gram negative (P. aeruginosa), gram positive (S. aureus) and ampicillin resistant gram-negative (E. coli) bacteria as well as were able to control inflammatory responses; properties which should lead to their further investigation for improved medical applications.

  17. Pre-terrestrial oxidation products in carbonaceous meteorites identified by Mossbauer spectroscopy

    NASA Technical Reports Server (NTRS)

    Burns, Roger G.; Fisher, Duncan S.

    1991-01-01

    The occurrence of ferric bearing assemblages, comprising phyllosilicates, oxide hydroxides and magnetite, in carbonaceous chondrites (CC) indicates that these meteorites underwent pre-terrestrial, sub-aqueous oxidation reactions. Reported here are results of a Mossbauer spectral study of a suite of CC demonstrating that a variety of ferrous and ferric bearing phases may be distinguished in different classes of this meteorite type.

  18. Formation of Metallic Nanophases in Polymeric Matrices for Space Applications

    NASA Technical Reports Server (NTRS)

    Orwoll, Robert A.; Thompson, David W.

    1999-01-01

    There are a select number of polyimides which are soluble in organic media. Incorporation of hexafluoroisopropylidene groups is a route to achieving solubility. Such fluorinated polyimides have desirable properties for processing and electronic purposes; however, they often have linear coefficients of thermal expansion (CTE) which are well above those for metals and inorganic oxides or ceramics with which they might be bonded. We have developed a synthesis of composite inorganic-polyimide films using diaquotris(2,4-pentane-dionato)lanthanam(III) as the inorganic precursor and two soluble polyimides formed from 2,2-bis(3,4- dicarboxyphenyl)hexafluoro-propane (6FDA) and 1,3-bis(3-aminophenoxy)benzene (APB) or 2,2-bis[4-(4-aminophenoxy)phenyllhexafluoropropane (4-BDAF). A primary goal of our work was to control the linear CTE in these fluorinated polymer composites without adversely affecting mechanical or other thermal properties.

  19. Particulate and THM precursor removal with ferric chloride

    SciTech Connect

    Childress, A.E.; Vrijenhoek, E.M.; Elimelech, M.; Tanaka, T.S.; Beuhler, M.D.

    1999-11-01

    Pilot-scale experiments were performed to investigate the effectiveness of enhanced coagulation in removing particles and trihalomethane (THM) precursors from two surface source waters: California State Project water and Colorado River water. The removal of suspended particles and natural organic matter at various ferric chloride doses and coagulation pHs was assessed through source water and filter effluent measurements of turbidity, particle count. UV{sub 254}, TOC, and THM formation potential. Overall, it was found that optimal removal of particles and THM precursors by enhanced coagulation with ferric chloride is obtained at high coagulant doses and low pH conditions. Generally, turbidity removal is more efficient and head loss is more moderate at ambient pH compared with pH 5.5. Additionally, filter effluent particle counts were found to be consistent with residual turbidity data. The removal of THM precursors by enhanced coagulation is significantly enhanced at pH 5.5 compared with ambient pH. The reduction in THM formation potential is consistent with the trends observed for the THM precursor removal data. Furthermore, specific UV absorbance was used to estimate the proportion of humic substances in the raw waters. Enhanced coagulation was found to be less effective for the source water with the lower specific UV absorbance.

  20. Intravenous ferric carboxymaltose for the treatment of iron deficiency anemia

    PubMed Central

    Friedrisch, Joo Ricardo; Canado, Rodolfo Delfini

    2015-01-01

    Nutritional iron deficiency anemia is the most common deficiency disorder, affecting more than two billion people worldwide. Oral iron supplementation is usually the first choice for the treatment of iron deficiency anemia, but in many conditions, oral iron is less than ideal mainly because of gastrointestinal adverse events and the long course needed to treat the disease and replenish body iron stores. Intravenous iron compounds consist of an iron oxyhydroxide core, which is surrounded by a carbohydrate shell made of polymers such as dextran, sucrose or gluconate. The first iron product for intravenous use was the high molecular weight iron dextran. However, dextran-containing intravenous iron preparations are associated with an elevated risk of anaphylactic reactions, which made physicians reluctant to use intravenous iron for the treatment of iron deficiency anemia over many years. Intravenous ferric carboxymaltose is a stable complex with the advantage of being non-dextran-containing and a very low immunogenic potential and therefore not predisposed to anaphylactic reactions. Its properties permit the administration of large doses (15mg/kg; maximum of 1000mg/infusion) in a single and rapid session (15-minute infusion) without the requirement of a test dose. The purpose of this review is to discuss some pertinent issues in relation to the history, pharmacology, administration, efficacy, and safety profile of ferric carboxymaltose in the treatment of patients with iron deficiency anemia. PMID:26670403

  1. Synthesis and characterization of akaganeite-like ferric oxyhydroxides

    SciTech Connect

    Linehan, J.C.; Darab, J.G.; Matson, D.W.; Chen, X.; Amonette, J.E.

    1997-08-01

    Iron-based powders have been used as catalytic and stoichiometric reactants in a variety of organic reactions and are receiving additional attention as ion exchange materials or once-through adsorbents for clean-up of toxic or radioactive waste streams. Recent efforts have been directed toward the design of iron-based products, in particular iron sulfides, capable of performing as hydrocracking catalysts for coal liquefaction and heavy crude or resid cracking. Here the authors present structural studies of new materials having akaganeite-like structures and of their use as hydrocracking catalyst precursors. Akaganeite, {beta}-FeOOH, a natural ferric oxyhydroxide mineral, has a structure containing tunnel-like cavities in which chloride ions reside. Analogs of akaganeite in which carbonate or sulfate groups replace the chloride ions have also been synthesized. Both akaganeite and its substituted analogs are known to be precursors for active hydrocracking catalysts. The authors present powder X-ray diffraction (XRD) and X-ray absorption fine-structure spectroscopy (XAFS) data confirming the synthesis of new ferric oxyhydroxides having structures similar to akaganeite, but contain molybdate and tungstate oxy-anions. They also present a new hydrothermal method to prepare this family of materials.

  2. Intravenous ferric carboxymaltose for the treatment of iron deficiency anemia.

    PubMed

    Friedrisch, Joo Ricardo; Canado, Rodolfo Delfini

    2015-01-01

    Nutritional iron deficiency anemia is the most common deficiency disorder, affecting more than two billion people worldwide. Oral iron supplementation is usually the first choice for the treatment of iron deficiency anemia, but in many conditions, oral iron is less than ideal mainly because of gastrointestinal adverse events and the long course needed to treat the disease and replenish body iron stores. Intravenous iron compounds consist of an iron oxyhydroxide core, which is surrounded by a carbohydrate shell made of polymers such as dextran, sucrose or gluconate. The first iron product for intravenous use was the high molecular weight iron dextran. However, dextran-containing intravenous iron preparations are associated with an elevated risk of anaphylactic reactions, which made physicians reluctant to use intravenous iron for the treatment of iron deficiency anemia over many years. Intravenous ferric carboxymaltose is a stable complex with the advantage of being non-dextran-containing and a very low immunogenic potential and therefore not predisposed to anaphylactic reactions. Its properties permit the administration of large doses (15mg/kg; maximum of 1000mg/infusion) in a single and rapid session (15-minute infusion) without the requirement of a test dose. The purpose of this review is to discuss some pertinent issues in relation to the history, pharmacology, administration, efficacy, and safety profile of ferric carboxymaltose in the treatment of patients with iron deficiency anemia. PMID:26670403

  3. 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

  4. Ferric and cobaltous hydroacid complexes for forward osmosis (FO) processes.

    PubMed

    Ge, Qingchun; Fu, Fengjiang; Chung, Tai-Shung

    2014-07-01

    Cupric and ferric hydroacid complexes have proven their advantages as draw solutes in forward osmosis in terms of high water fluxes, negligible reverse solute fluxes and easy recovery (Ge and Chung, 2013. Hydroacid complexes: A new class of draw solutes to promote forward osmosis (FO) processes. Chemical Communications 49, 8471-8473.). In this study, cobaltous hydroacid complexes were explored as draw solutes and compared with the ferric hydroacid complex to study the factors influencing their FO performance. The solutions of the cobaltous complexes produce high osmotic pressures due to the presence of abundant hydrophilic groups. These solutes are able to dissociate and form a multi-charged anion and Na(+) cations in water. In addition, these complexes have expanded structures which lead to negligible reverse solute fluxes and provide relatively easy approaches in regeneration. These characteristics make the newly synthesized cobaltous complexes appropriate as draw solutes. The FO performance of the cobaltous and ferric-citric acid (Fe-CA) complexes were evaluated respectively through cellulose acetate membranes, thin-film composite membranes fabricated on polyethersulfone supports (referred as TFC-PES), and polybenzimidazole and PES dual-layer (referred as PBI/PES) hollow fiber membranes. Under the conditions of DI water as the feed and facing the support layer of TFC-PES FO membranes (PRO mode), draw solutions at 2.0 M produced relatively high water fluxes of 39-48 LMH (L m(-2) hr(-1)) with negligible reverse solute fluxes. A water flux of 17.4 LMH was achieved when model seawater of 3.5 wt.% NaCl replaced DI water as the feed and 2.0 M Fe-CA as the draw solution under the same conditions. The performance of these hydroacid complexes surpasses those of the synthetic draw solutes developed in recent years. This observation, along with the relatively easy regeneration, makes these complexes very promising as a novel class of draw solutes. PMID:24768702

  5. Nanophase separation in monomolecularly thin water-ethanol films controlled by graphene.

    PubMed

    Severin, N; Gienger, J; Scenev, V; Lange, P; Sokolov, I M; Rabe, J P

    2015-02-11

    Control over nanoscale patterning of ultrathin molecular films plays an important role both in natural as well as artificial nanosystems. Here we report on nanophase separated patterns of water and ethanol within monomolecularly thin films confined between the cleavage plane of mica and single or a few layers of graphene. Employing scanning force microscopy of the graphene layers conforming to the molecular films we quantify the patterns using the ethanol-water cross correlation and the autocorrelation of domain wall directions. They reveal that lateral pattern dimensions grow and the domain walls stiffen upon increasing the thickness of the graphene multilayers. We attribute the control of the patterns through the graphene layers to the competition between the mechanical deformation energy of the graphene sheets and the electrostatic repulsion of dipoles normal to the interface. The latter results from charge transfer between graphene and the molecules confined between mica and graphene. PMID:25615007

  6. The Optical Properties of Nanophase Iron: Investigation of a Space Weathering Analog

    NASA Technical Reports Server (NTRS)

    Noble, S. K.; Pieters, C. M.; Keller, L. P.

    2003-01-01

    It is known that space weathering, in particular the nanophase iron (npFe(sup 0)) created via vapor and/or sputter deposition, has distinct and predictable effects on the optical properties of lunar soils. In addition to the attenuation of absorption bands, weathering introduces a characteristic continuum which is controlled by the amount of npFe(sup 0) present. The shape of this continuum may also be controlled by the size of the npFe(sup 0) grains. It is thought that small npFe(sup 0) grains result in reddening, while larger grains only darken the material. To investigate this phenomenon we have created a lunar weathering analog by impregnating silica gel powders with npFe(sup 0) following the methods presented.

  7. Electro-optic effects in nanophase polymer dispersed liquid-crystal systems

    SciTech Connect

    Blacker, R.S.; Lewis, K.L.; Mason, I.; Sage, I.; Webb, K.

    1998-07-01

    Research into electro-optic effects in nanophase polymer dispersed liquid crystal (PDLC) materials has highlighted their potential as materials for a new class of tunable filters. The structures, based on UV cured phase separated composites, contain liquid crystal both as discrete nano-scale droplets, and as material dissolved in the polymeric host. The essential difference between these materials and more conventional PDLC's is the scale of the refractive index inhomogeneity which is considerably smaller than the wavelength of visible light. Based upon effective medium approximations, the composite thus acts as a single isotropic medium, whose average refractive index is dependent on the level of applied electric field. Tunable filters have been fabricated using the composite material for use in the visible spectral band.

  8. Experimental Evidence of the Origin of Nanophase Separation in Low Hole-Doped Colossal Magnetoresistant Manganites.

    PubMed

    Corts-Gil, Raquel; Ruiz-Gonzlez, M Luisa; Gonzlez-Merchante, Daniel; Alonso, Jos M; Hernando, Antonio; Trasobares, Susana; Vallet-Reg, Mara; Rojo, Juan M; Gonzlez-Calbet, Jos M

    2016-01-13

    While being key to understanding their intriguing physical properties, the origin of nanophase separation in manganites and other strongly correlated materials is still unclear. Here, experimental evidence is offered for the origin of the controverted phase separation mechanism in the representative La1-xCaxMnO3 system. For low hole densities, direct evidence of Mn(4+) holes localization around Ca(2+) ions is experimentally provided by means of aberration-corrected scanning transmission electron microscopy combined with electron energy loss spectroscopy. These localized holes give rise to the segregated nanoclusters, within which double exchange hopping between Mn(3+) and Mn(4+) remains restricted, accounting for the insulating character of perovskites with low hole density. This localization is explained in terms of a simple model in which Mn(4+) holes are bound to substitutional divalent Ca(2+) ions. PMID:26683223

  9. Ultraviolet and white photon avalanche upconversion in Ho{sup 3+}-doped nanophase glass ceramics

    SciTech Connect

    Lahoz, F.; Martin, I.R.; Calvilla-Quintero, J.M.

    2005-01-31

    Ho{sup 3+}-doped fluoride nanophase glass ceramics have been synthesized from silica-based oxyfluoride glass. An intense white emission light is observed by the naked eye under near infrared excitation at 750 nm. This visible upconversion is due to three strong emission bands in the primary color components, red, green, and blue. Besides, ultraviolet signals are also recorded upon the same excitation wavelength. The excitation mechanism of both the ultraviolet and the visible emissions is a photon avalanche process with a relatively low pump power threshold at about 20 mW. The total upconverted emission intensity has been estimated to increase by about a factor of 20 in the glass ceramic compared to the precursor glass, in which an avalanche type mechanism is not generated.

  10. QTL analysis of ferric reductase activity in the model legume lotus japonicus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Physiological and molecular studies have demonstrated that iron accumulation from the soil into Strategy I plants can be limited by ferric reductase activity. An initial study of Lotus japonicus ecotypes Miyakojima MG-20 and Gifu B-129 identified significant leaf chlorosis and ferric reductase activ...

  11. Stabilisation of Fe2O3-rich Perovskite Nanophase in Epitaxial Rare-earth Doped BiFeO3 Films

    PubMed Central

    Zhang, Huairuo; Reaney, Ian M.; Marincel, Daniel M.; Trolier-McKinstry, Susan; Ramasse, Quentin M.; MacLaren, Ian; Findlay, Scott D.; Fraleigh, Robert D.; Ross, Ian M.; Hu, Shunbo; Ren, Wei; Mark Rainforth, W.

    2015-01-01

    Researchers have demonstrated that BiFeO3 exhibits ferroelectric hysteresis but none have shown a strong ferromagnetic response in either bulk or thin film without significant structural or compositional modification. When remanent magnetisations are observed in BiFeO3 based thin films, iron oxide second phases are often detected. Using aberration-corrected scanning transmission electron microscopy, atomic resolution electron energy loss spectrum-mapping and quantitative energy dispersive X-ray spectroscopy analysis, we reveal the existence of a new Fe2O3-rich perovskite nanophase, with an approximate formula (Fe0.6Bi0.25Nd0.15)3+ Fe3+O3, formed within epitaxial Ti and Nd doped BiFeO3 perovskite films grown by pulsed laser deposition. The incorporation of Nd and Bi ions on the A-site and coherent growth with the matrix stabilise the Fe2O3-rich perovskite phase and preliminary density functional theory calculations suggest that it should have a ferrimagnetic response. Perovskite-structured Fe2O3 has been reported previously but never conclusively proven when fabricated at high-pressure high-temperature. This work suggests the incorporation of large A-site species may help stabilise perovskite-structured Fe2O3. This finding is therefore significant not only to the thin film but also to the high-pressure community. PMID:26272264

  12. Stabilisation of Fe2O3-rich Perovskite Nanophase in Epitaxial Rare-earth Doped BiFeO3 Films.

    PubMed

    Zhang, Huairuo; Reaney, Ian M; Marincel, Daniel M; Trolier-McKinstry, Susan; Ramasse, Quentin M; MacLaren, Ian; Findlay, Scott D; Fraleigh, Robert D; Ross, Ian M; Hu, Shunbo; Ren, Wei; Rainforth, W Mark

    2015-01-01

    Researchers have demonstrated that BiFeO3 exhibits ferroelectric hysteresis but none have shown a strong ferromagnetic response in either bulk or thin film without significant structural or compositional modification. When remanent magnetisations are observed in BiFeO3 based thin films, iron oxide second phases are often detected. Using aberration-corrected scanning transmission electron microscopy, atomic resolution electron energy loss spectrum-mapping and quantitative energy dispersive X-ray spectroscopy analysis, we reveal the existence of a new Fe2O3-rich perovskite nanophase, with an approximate formula (Fe0.6Bi0.25Nd0.15)(3+) Fe(3+)O3, formed within epitaxial Ti and Nd doped BiFeO3 perovskite films grown by pulsed laser deposition. The incorporation of Nd and Bi ions on the A-site and coherent growth with the matrix stabilise the Fe2O3-rich perovskite phase and preliminary density functional theory calculations suggest that it should have a ferrimagnetic response. Perovskite-structured Fe2O3 has been reported previously but never conclusively proven when fabricated at high-pressure high-temperature. This work suggests the incorporation of large A-site species may help stabilise perovskite-structured Fe2O3. This finding is therefore significant not only to the thin film but also to the high-pressure community. PMID:26272264

  13. 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.

  14. Niobium Uptake and Release by Bacterial Ferric Ion Binding Protein

    PubMed Central

    Shi, Yanbo; Harvey, Ian; Campopiano, Dominic; Sadler, Peter J.

    2010-01-01

    Ferric ion binding proteins (Fbps) transport FeIII across the periplasm and are vital for the virulence of many Gram negative bacteria. Iron(III) is tightly bound in a hinged binding cleft with octahedral coordination geometry involving binding to protein side chains (including tyrosinate residues) together with a synergistic anion such as phosphate. Niobium compounds are of interest for their potential biological activity, which has been little explored. We have studied the binding of cyclopentadienyl and nitrilotriacetato NbV complexes to the Fbp from Neisseria gonorrhoeae by UV-vis spectroscopy, chromatography, ICP-OES, mass spectrometry, and Nb K-edge X-ray absorption spectroscopy. These data suggest that NbV binds strongly to Fbp and that a dinuclear NbV centre can be readily accommodated in the interdomain binding cleft. The possibility of designing niobium-based antibiotics which block iron uptake by pathogenic bacteria is discussed. PMID:20445753

  15. 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.

  16. Transcriptional regulation by Ferric Uptake Regulator (Fur) in pathogenic bacteria

    PubMed Central

    Troxell, Bryan; Hassan, Hosni M.

    2013-01-01

    In the ancient anaerobic environment, ferrous iron (Fe2+) was one of the first metal cofactors. Oxygenation of the ancient world challenged bacteria to acquire the insoluble ferric iron (Fe3+) and later to defend against reactive oxygen species (ROS) generated by the Fenton chemistry. To acquire Fe3+, bacteria produce low-molecular weight compounds, known as siderophores, which have extremely high affinity for Fe3+. However, during infection the host restricts iron from pathogens by producing iron- and siderophore-chelating proteins, by exporting iron from intracellular pathogen-containing compartments, and by limiting absorption of dietary iron. Ferric Uptake Regulator (Fur) is a transcription factor which utilizes Fe2+ as a corepressor and represses siderophore synthesis in pathogens. Fur, directly or indirectly, controls expression of enzymes that protect against ROS damage. Thus, the challenges of iron homeostasis and defense against ROS are addressed via Fur. Although the role of Fur as a repressor is well-documented, emerging evidence demonstrates that Fur can function as an activator. Fur activation can occur through three distinct mechanisms (1) indirectly via small RNAs, (2) binding at cis regulatory elements that enhance recruitment of the RNA polymerase holoenzyme (RNAP), and (3) functioning as an antirepressor by removing or blocking DNA binding of a repressor of transcription. In addition, Fur homologs control defense against peroxide stress (PerR) and control uptake of other metals such as zinc (Zur) and manganese (Mur) in pathogenic bacteria. Fur family members are important for virulence within bacterial pathogens since mutants of fur, perR, or zur exhibit reduced virulence within numerous animal and plant models of infection. This review focuses on the breadth of Fur regulation in pathogenic bacteria. PMID:24106689

  17. Leaching of bornite in acidified ferric chloride solutions

    NASA Astrophysics Data System (ADS)

    Pesic, B.; Olson, F. A.

    1983-12-01

    In an acidified ferric chloride solution, bornite leaches in two stages of reaction with the first being relatively much more rapid than the second; the first terminates at 28 pct copper dissolution. The first-stage dissolution reaction is electrochemical and is mixed kinetics-controlled; ferric-ion transfer through the solution boundary layer and reduction on the surface to release Cu2+ into solution are both important in controlling the rate. The concentration of labile Cu+ in the bornite lattice governs the potential of the surface reaction, and, once Cu+ is depleted from the original bornite, stage-I reaction ceases. The solid reaction intermediate formed is Cu3FeS4. Minute subcrystallites formed at the latter part of stage I leach topochemically in stage II. This reaction which commences at 28 pct Cu dissolution is characterized by a change in mechanism at about 40 pct copper dissolution, though the overall chemical equation for reaction is unchanged in stage II; cupric and ferrous ions and sulfur as a solid residue are products of reaction. The region 28 to about 40 pct Cu dissolution is designated as a transition period to stage-II reaction. Reaction rate in this period is interpreted as being controlled by reduction of Fe3+ on active product sulfur surface sites, and hence the reaction rate is controlled by the rate of nucleation and growth of sulfur on the Cu3FeS4 intermediate surfaces. Strain in the Cu3FeS4 crystal lattice is released during this period by diffusion from the lattice of Cu+ remaining from the labile copper initially present in the bornite. After about 40 pct Cu dissolution the rate of reaction is controlled by diffusion through the fully formed sulfur layer in an equiaxial geometrically controlled reaction.

  18. Synchrotron Characterization of Hydrogen and Ferric Iron in Martian Meteorites

    NASA Technical Reports Server (NTRS)

    Dyar, Melinda D.

    2003-01-01

    The hydrogen budget of the Martian interior is distributed among several phases: melts, hydrous minerals, and nominally anhydrous minerals like olivine, pyroxene, and garnet. All these phases are vulnerable to loss of hydrogen during shock, excavation and transport via the mechanism of dehydrogenation, in which the charge on the H protons is left behind as polarons on Fe atoms. Thus, both H and F(3x) must be analyzed in order to reconstruct hydrogen and oxygen fugacities on Mars. To date, SIMS data have elucidated D/H and H contents of hydrous phases in SNC meteorites, but anhydrous martian minerals have not been systematically examined for trace hydrogen. Ferric iron has been quantified using XANES in many marital phases, but integrated studies of both Fe(3x) and H on the same spots are really needed to address the H budget. Here, we measure and profile H and Fe(3x) abundances in and across individual grains of glass and silicates in Martian meteorites. We use the new technology of synchrotron microFI'lR spectroscopy to measure the hydrogen contents of hydrous and nominally anhydrous minerals in martian meteorites on 30-100 microns thick, doubly polished thin sections on spots down to 3 x 3 microns. Synchrotron microXANES was used to analyze Fe(3x) on the same scale, and complementary SIMS D/H data will be collected where possible, though at a slightly larger scale. Development of this combination of techniques is critical because future sample return missions will generate only microscopic samples for study. Results have been used to quantitatively assess the distribution of hydrogen and ferric iron among phases in the martian interior, which will better constrain the geodynamic processes of the interior, as well as the overall hydrogen and water budgets on Mars.

  19. Fe{sup II} induced mineralogical transformations of ferric oxyhydroxides into magnetite of variable stoichiometry and morphology

    SciTech Connect

    Usman, M.; CNRS, Laboratoire de Chimie Physique et Microbiologie pour l'Environnement, LCPME, UMR 7564, Institut Jean Barriol, CNRS-, 405 rue de Vandoeuvre, 54600 Villers-les-Nancy; Institute of Soil and Environmental Sciences, University of Agriculture, Faisalabad 38040 ; Abdelmoula, M.; CNRS, Laboratoire de Chimie Physique et Microbiologie pour l'Environnement, LCPME, UMR 7564, Institut Jean Barriol, CNRS-, 405 rue de Vandoeuvre, 54600 Villers-les-Nancy ; Hanna, K.; CNRS, Laboratoire de Chimie Physique et Microbiologie pour l'Environnement, LCPME, UMR 7564, Institut Jean Barriol, CNRS-, 405 rue de Vandoeuvre, 54600 Villers-les-Nancy; Ecole Nationale Superieure de Chimie de Rennes, UMR CNRS 6226 'Sciences Chimiques de Rennes', Avenue du General Leclerc, 35708 Rennes Cedex 7 ; and others

    2012-10-15

    The Moessbauer spectroscopy was used to monitor the mineralogical transformations of ferrihydrite (F), lepidocrocite (L) and goethite (G) into magnetite as a function of aging time. Ferric oxyhydroxides were reacted with soluble Fe{sup II} and OH{sup -} in stoichiometric amounts to form magnetite at an initial pH of {approx}9.7. Observed transformation extent into magnetite followed the order: F>L>G with almost 30% of untransformed G after 1 month. The departure from stoichiometry, {delta}, of magnetite (Fe{sub 3-{delta}}O{sub 4}) generated from F ({delta}{approx}0.04) and L ({delta}{approx}0.05) was relatively low as compared to that in magnetite from G ({delta}{approx}0.08). The analysis by transmission electron microscopy and BET revealed that generated magnetite was also different in terms of morphology, particle size and surface area depending on the nature of initial ferric oxyhydroxide. This method of preparation is a possible way to form nano-sized magnetite. - Graphical abstract: Moessbauer spectrum of the early stage of magnetite formation formed from the interaction of adsorbed Fe{sup II} species with goethite. Highlights: Black-Right-Pointing-Pointer Ferric oxides were reacted with hydroxylated Fe{sup II} to form magnetite. Black-Right-Pointing-Pointer Magnetite formation was quantified as a function of aging time. Black-Right-Pointing-Pointer Complete transformation of ferrihydrite and lepidocrocite was achieved. Black-Right-Pointing-Pointer Almost 70% of initial goethite was transformed. Black-Right-Pointing-Pointer Resulting magnetites have differences in stoichiometry and morphological properties.

  20. Application of granular ferric hydroxides for removal elevated concentrations of arsenic from mine waters

    NASA Astrophysics Data System (ADS)

    Szlachta, Małgorzata; Włodarczyk, Paweł; Wójtowicz, Patryk

    2015-04-01

    Arsenic is naturally occurring element in the environment. Over three hundred minerals are known to contain some form of arsenic and among them arsenopyrite is the most common one. Arsenic-bearing minerals are frequently associated with ores containing mined metals such as copper, tin, nickel, lead, uranium, zinc, cobalt, platinum and gold. In the aquatic environment arsenic is typically present in inorganic forms, mainly in two oxidation states (+5, +3). As(III) is dominant in more reduced conditions, whereas As(V) is mostly present in an oxidizing environment. However, due to certain human activities the elevated arsenic levels in aquatic ecosystems are arising to a serious environmental problem. High arsenic concentrations found in surface and groundwaters, in some regions originate from mining activities and ore processing. Therefore, the major concern of mining industry is to maintain a good quality of effluents discharged in large volumes. This requires constant monitoring of effluents quality that guarantee the efficient protection of the receiving waters and reacting to possible negative impact of contamination on local communities. A number of proven technologies are available for arsenic removal from waters and wastewaters. In the presented work special attention is given to the adsorption method as a technically feasible, commonly applied and effective technique for the treatment of arsenic rich mine effluents. It is know that arsenic has a strong affinity towards iron rich materials. Thus, in this study the granular ferric hydroxides (CFH 12, provided by Kemira Oyj, Finland) was applied to remove As(III) and As(V) from aqueous solutions. The batch adsorption experiments were carried out to assess the efficiency of the tested Fe-based material under various operating parameters, including composition of treated water, solution pH and temperature. The results obtained from the fixed bed adsorption tests demonstrated the benefits of applying granular ferric hydroxides for treatment As-contaminated waters. This research is a part of the study supported by the National Centre for Research and Development grant (2014-2017) "Sustainable and responsible supply of primary resources - SUSMIN" (http://projects.gtk.fi/susmin), within the EU ERA-NET ERA-MIN program.

  1. Deposition rates of oxidized iron on Mars

    NASA Technical Reports Server (NTRS)

    Burns, R. G.

    1993-01-01

    The reddened oxidized surface of Mars is indicative of temporal interactions between the Martian atmosphere and its surface. During the evolution of the Martian regolith, primary ferromagnesian silicate and sulfide minerals in basaltic rocks apparently have been oxidized to secondary ferric-bearing assemblages. To evaluate how and when such oxidized deposits were formed on Mars, information about the mechanisms and rates of chemical weathering of Fe(2+)-bearing minerals has been determined. In this paper, mechanisms and rates of deposition of ferric oxide phases on the Martian surface are discussed.

  2. Strong Oxidants are Needed to form Sulfates in CM Chondrites

    NASA Astrophysics Data System (ADS)

    Zolotov, M. Yu.

    2013-09-01

    Oxidants (O_2, H_2O_2, O_3, etc.) produced through radiolysis and photolysis of water ice in the solar nebula could be responsible for formation of sulfates and some ferric phases in carbonaceous chondrites.

  3. Nanophasic biodegradation enhances the durability and biocompatibility of magnesium alloys for the next-generation vascular stents

    NASA Astrophysics Data System (ADS)

    Mao, Lin; Shen, Li; Niu, Jialin; Zhang, Jian; Ding, Wenjiang; Wu, Yu; Fan, Rong; Yuan, Guangyin

    2013-09-01

    Biodegradable metal alloys emerge as a new class of biomaterials for tissue engineering and medical devices such as cardiovascular stents. Deploying biodegradable materials to fabricate stents not only obviates a second surgical intervention for implant removal but also circumvents the long-term foreign body effect of permanent implants. However, these materials for stents suffer from an un-controlled degradation rate, acute toxic responses, and rapid structural failure presumably due to a non-uniform, fast corrosion process. Here we report that highly uniform, nanophasic degradation is achieved in a new Mg alloy with unique interstitial alloying composition as the nominal formula Mg-2.5Nd-0.2Zn-0.4Zr (wt%, hereafter, denoted as JDBM). This material exhibits highly homogeneous nanophasic biodegradation patterns as compared to other biodegradable metal alloy materials. Consequently it has significantly reduced degradation rate determined by electrochemical characterization. The in vitro cytotoxicity test using human vascular endothelial cells indicates excellent biocompatibility and potentially minimal toxic effect on arterial vessel walls. Finally, we fabricated a cardiovascular stent using JDBM and performed in vivo long-term assessment via implantation of this stent in an animal model. The results confirmed the reduced degradation rate in vivo, excellent tissue compatibility and long-term structural and mechanical durability. Thus, this new Mg-alloy with highly uniform nanophasic biodegradation represents a major breakthrough in the field and a promising material for manufacturing the next generation biodegradable vascular stents.

  4. [Stabilization of Cadmium Contaminated Soils by Ferric Ion Modified Attapulgite (Fe/ATP)--Characterizations and Stabilization Mechanism].

    PubMed

    Rong, Yang; Li, Rong-bo; Zhou, Yong-li; Chen, Jing; Wang, Lin-ling; Lu, Xiao-hua

    2015-08-01

    Ferric ion modified attapulgite (Fe/ATP) was prepared by impregnation and its structure and morphology were characterized. The toxicity characteristic leaching procedure (TCLP) was used to evaluate the effect of Cadmium( Cd) stabilization in soil with the addition of attapulgite (ATP) and Fe/ATP. The stabilization mechanism of Cd was further elucidated by comparing the morphologies and structure of ATP and Fe/ATP before and after Cd adsorption. Fe/ATP exhibited much better adsorption capacity than ATP, suggesting different adsorption mechanisms occurred between ATP and Fe/ATP. The leaching concentrations of Cd in soil decreased by 45% and 91% respectively, with the addition of wt. 20% ATP and Fe/ATP. The former was attributed to the interaction between Cd2 and --OH groups by chemical binding to form inner-sphere complexes in ATP and the attachment between Cd2+ and the defect sites in ATP framework. Whereas Cd stabilization with Fe/ATP was resulted from the fact that the active centers (--OH bonds or O- sites) on ATP could react with Fe3+ giving Fe--O--Cd-- bridges, which helped stabilize Cd in surface soil. What'more, the ferric oxides and metal hydroxides on the surface of ATP could interact with Cd, probably by the formation of cadmium ferrite. In conclusion, Fe/ATP, which can be easily prepared, holds promise as a potential low-cost and environmental friendly stabilizing agent for remediation of soil contaminated with heavy metals. PMID:26592037

  5. Ferrous iron formation following the co-aggregation of ferric iron and the Alzheimer's disease peptide ?-amyloid (1-42).

    PubMed

    Everett, J; Cspedes, E; Shelford, L R; Exley, C; Collingwood, J F; Dobson, J; van der Laan, G; Jenkins, C A; Arenholz, E; Telling, N D

    2014-06-01

    For decades, a link between increased levels of iron and areas of Alzheimer's disease (AD) pathology has been recognized, including AD lesions comprised of the peptide ?-amyloid (A?). Despite many observations of this association, the relationship between A? and iron is poorly understood. Using X-ray microspectroscopy, X-ray absorption spectroscopy, electron microscopy and spectrophotometric iron(II) quantification techniques, we examine the interaction between A?(1-42) and synthetic iron(III), reminiscent of ferric iron stores in the brain. We report A? to be capable of accumulating iron(III) within amyloid aggregates, with this process resulting in A?-mediated reduction of iron(III) to a redox-active iron(II) phase. Additionally, we show that the presence of aluminium increases the reductive capacity of A?, enabling the redox cycling of the iron. These results demonstrate the ability of A? to accumulate iron, offering an explanation for previously observed local increases in iron concentration associated with AD lesions. Furthermore, the ability of iron to form redox-active iron phases from ferric precursors provides an origin both for the redox-active iron previously witnessed in AD tissue, and the increased levels of oxidative stress characteristic of AD. These interactions between A? and iron deliver valuable insights into the process of AD progression, which may ultimately provide targets for disease therapies. PMID:24671940

  6. Processes for extraction of uranium and radium from uranium-containing ores using ferric nitrate

    SciTech Connect

    Nirdosh, I.

    1987-03-10

    A process is described for the extraction of both uranium and radium from uranium ores in the presence of an interfering sulfate ion resulting from the presence of sulfide therein by use of an aqueous ferric nitrate leachant including the steps of: (a) mechanically treating the finely ground ore for the removal of sulfide therefrom; (b) leaching the mechanically treated finely ground ore with aqueous acidic ferric nitrate solution in a concentration from 0.01 to 0.1M for the removal of uranium and radium therefrom to result in a liquid ferric nitrate leachate containing radium and uranium and a wet cake containing radium, uranium and ferric nitrate; (c) treating the ferric nitrate leachate to separate uranium and radium therefrom; (d) separately treating the wet cake for removal of retained ferric nitrate and the residual radium and uranium therefrom; and (e) recirculating a major portion of the ferric nitrate leachate from step (c) for the leaching of more of the mechanically treated finely ground ore.

  7. Mssbauer and infrared spectroscopy as a diagnostic tool for the characterization of ferric tannates

    NASA Astrophysics Data System (ADS)

    Jan, Juan A.; Navarro, Csar

    2009-07-01

    Fourier transform infrared spectroscopy and Mssbauer spectroscopy are use for the characterization and qualitative analysis of hydrolysable and condensed tannates. The two classes of tannates may be differentiated from the characteristic IR pattern. Mssbauer proof that a mixture of mono- and bis-type ferric tannate complexes, and an iron(II)-tannin complex are obtained from the interaction of hydrolysable tannins (tannic acid and chestnut tannin) and condensed tannins (mimosa and quebracho) with a ferric nitrate solution. At pH 7, a partially hydrolyzed ferric tannate complex was also obtained.

  8. Formation of ferric iron crusts in Quaternary sediments of Lake Baikal, Russia, and implications for paleoclimate

    USGS Publications Warehouse

    Deike, R.G.; Granina, L.; Callender, E.; McGee, J.J.

    1997-01-01

    Phosphate-bearing, ferric iron and siliceous crusts ranging in age from Recent to approximately 65,000 yr B.P. are observed in sediments of Lake Baikal. In younger sediments the crusts are at the base of a spectrum of secondary iron and manganese oxides that accumulate near the sediment/water interface in the zone of positive oxidation potential beneath an oxygenated water column. In areas where the average Quaternary sedimentation rates have been slow (e.g. 0.026 mm/yr), the crusts are more common, and span a wider range of ages. No crusts have been found where the Quaternary sedimentation mode has been deltaic and rapid (0.15 mm/yr). Independent core correlation based on magnetic properties of the sediment suggests that crusts can be correlated over most of Academician Ridge, an area that is particularly sensitive to climatic events affecting the concentration of suspended sediment. These crusts may be indicative of periods of low suspended sediment concentration, which occur during sustained transitions from glacial periods of high detrital input, to interglacial periods of high diatom sedimentation. The crusts are dominated by iron-rich and siliceous amorphous mineral phases, with an FeO:SiO2 by weight of 3:1. Regardless of age or location in the lake the Fe phase always includes Ca, P and Mn. Extensive microprobe data for these four elements recast as normalized elemental weight percent reveal linear trends of Ca:P and Fe:P. With increasing P, Ca also increases such that the two elements maintain a linear relationship passing very close to the origin and with a mean molar Ca:P=0.3 (too low for well-characterized apatite). Conversely, with increasing P, Fe decreases (mean molar Fe:P=3.4). There is no correlation between Mn and P. Molar Fe:P ratios for vivianite (an Fe(II) phosphate mineral observed in sediments closely below some crusts) are clustered around a stoichiometric composition. The covariant increase in Ca:P and the corresponding decrease in Fe:P may be explained by: (1) coupled adsorption of aqueous Ca and P by a colloidal ferric hydrous oxide; (2) loss of Fe from a Ca-P-Fe phase; or (3) oxidation of vivianite to a metastable mineral phase that gradually loses Ca and gains Fe. The first explanation is favored, because there is no petrographic evidence for either the existence of an originating Ca-P-Fe phase, or, for the oxidation of vivianite. Further, it is suggested that by continually equalizing surface charge, Ca allows more phosphate to be adsorbed leading to thicker crusts and longer preservation after burial.

  9. Amelioration of ferric nitrilotriacetate-induced hepatotoxicity in Wistar rats by diallylsulfide.

    PubMed

    Ansar, S; Iqbal, M

    2016-03-01

    Garlic contains diallylsulfide (DAS) and other structurally related compounds that are widely believed to be active agents in preventing cancer. This study shows the effect of DAS (a phenolic antioxidant used in foods, cosmetics, and pharmaceutical products : on ferric nitrilotriacetate (Fe-NTA)-induced hepatotoxicity in rats. Male albino rats of Wistar strain weighing 125-150 g were given a single dose of Fe-NTA (9 mg kg(-1) body weight, intraperitoneally) after 1 week of treatment with 100 and 200 mg kg(-1) DAS in corn oil respectively administered through the gavage. Fe-NTA administration led to 2.5-fold increase in the values of both alanine transaminase and aspartate aminotransferase, respectively, and 3.2-fold increase in the activity of lactate dehydrogenase, microsomal lipid peroxidation to approximately 2.0-fold compared to saline-treated control. The activities of glutathione (GSH) and other antioxidant enzymes decreased to a range of 2.2-2.5-fold. These changes were reversed significantly (p < 0.001) in animals receiving a pretreatment of DAS. DAS protected against hepatic lipid peroxidation, hydrogen peroxide generation, preserved GSH levels, and GSH metabolizing enzymes to 60-80% as compared to Fe-NTA alone-treated group. Present data suggest that DAS can ameliorate the toxic effects of Fe-NTA and suppress oxidant-induced tissue injury and hepatotoxicity in rats. PMID:25904316

  10. Near the Ferric Pseudobrookite Composition (Fe2TiO5).

    PubMed

    Seitz, Guillaume; Penin, Nicolas; Decoux, Léa; Wattiaux, Alain; Duttine, Mathieu; Gaudon, Manuel

    2016-03-01

    Because of a very low thermodynamic stability, obtaining a pure monophasic compound of ferric pseudobrookite is quite difficult to achieve. Indeed, the low reticular energy of this phase leads easily to its decomposition and the occurrence of the secondary phases: hematite (Fe2O3) and/or rutile (TiO2). Samples with global composition Fe2-xTi1+xO5 (x = 0, 0.05, and 0.10) have been synthesized by the Pechini route and, thereafter, thermally treated at different temperatures. The concentrations of Fe2O3 and TiO2 secondary phases were accurately determined and correlated with the target compositions and the synthesis parameters, especially the thermal treatment temperature. As revealed by Mössbauer spectroscopy, all iron ions are at the III+ oxidation state. Thus, the formation of hematite or rutile as a secondary phase may be related to the occurrence of cationic vacancies within the pseudobrookite structure, with the amount of vacancies depending on the annealing temperature. In light of the presented results, it appears unreasonable to propose a "fixed" binary phase diagram for such a complex system. Furthermore, the occurrence of cationic vacancies induces a coloration change (darkening), preventing any industrial use of this reddish-brown pseudobrookite as a ceramic pigment. PMID:26866894

  11. Iron Amendment and Fenton Oxidation of MTBE-Spent Granular Activated Carbon

    EPA Science Inventory

    Fenton-driven regeneration of Methyl tert-butyl ether (MTBE)-spent granular activated carbon (GAC) involves Fe amendment to the GAC to catalyze H2O2 reactions and to enhance the rate of MTBE oxidation and GAC regeneration. Four forms of iron (ferric sulfate, ferric chloride, fer...

  12. Formation of Nanophase Iron in Lunar Soil Simulant for Use in ISRU Studies

    NASA Technical Reports Server (NTRS)

    Liu, Yang; Taylor, Lawrence A.; Hill, Eddy; Day, James D. M.

    2005-01-01

    For the prospective return of humans to the Moon and the extensive amount of premonitory studies necessary, large quantities of lunar soil simulants are required, for a myriad of purposes from construction/engineering purposes all the way to medical testing of its effects from ingestion by humans. And there is only a limited and precious quantity of lunar soil available on Earth (i.e., Apollo soils) - therefore, the immediate need for lunar soil simulants. Since the Apollo era, there have been several simulants; of these JSC-1 (Johnson Space Center) and MLS-1 (Minnesota Lunar Simulant) have been the most widely used. JSC-1 was produced from glassy volcanic tuff in order to approximate lunar soil geotechnical properties; whereas, MLS-1 approximates the chemistry of Apollo 11 high-Ti soil, 10084. Stocks of both simulants are depleted, but JSC-1 has recently gone back into production. The lunar soil simulant workshop, held at Marshall Space Flight Center in January 2005, identified the need to make new simulants for the special properties of lunar soil, such as nanophase iron (np-Fe(sup 0). Hill et al. (2005, this volume) showed the important role of microscale Fe(sup 0) in microwave processing of the lunar soil simulants JSC-1 and MLS-1. Lunar soil is formed by space weathering of lunar rocks (e.g., micrometeorite impact, cosmic particle bombardment). Glass generated during micrometeorite impact cements rock and mineral fragments together to form aggregates called agglutinates, and also produces vapor that is deposited and coats soil grains. Taylor et al. (2001) showed that the relative amount of impact glass in lunar soil increases with decreasing grain size and is the most abundant component in lunar dust (less than 20 micrometer fraction). Notably, the magnetic susceptibility of lunar soil also increases with the decreasing grain size, as a function of the amount of nanophase-sized Fe(sup 0) in impact-melt generated glass. Keller et al. (1997, 1999) also discovered the presence of abundant np-Fe(sup 0) particles in the glass patinas coating most soil particles. Therefore, the correlation of glass content and magnetic susceptibility can be explained by the presence of the np-Feo particles in glass: small particles contain relatively more np-Fe(sup 0) as glass coatings because the surface area versus mass ratio of the grain size is so increased. The magnetic properties of lunar soil are important in dust mitigation on the Moon (Taylor et al. 2005). Thus material simulating this property is important for testing mitigation methods using electromagnetic field. This np- Fe(sup 0) also produces a unique energy coupling to normal microwaves, such as present in kitchen microwave ovens. Effectively, a portion of lunar soil placed in a normal 2.45 GHz oven will melt at greater than 1200 C before your tea will boil at 100 C, a startling and new discovery reported by Taylor and Meek (2004, 2005). Several methods have been investigated in attempts to make nanophase-sized Feo dispersed within silicate glass; like in the lunar glass. We have been successful in synthesizing such a product and continue to improve on our recipe. We have performed extensive experimentation on this subject to date. Ultimately it will probably be necessary to add this np-Fe(sup 0) bearing silicate glass to lunar soil stimulant, like JSC-1, to actually produce the desired magnetic and microwave coupling properties for use in appropriate ISRU experimentation.

  13. How the Ferric Iron Proportion in Basalts Changes Towards the Iceland Plume

    NASA Astrophysics Data System (ADS)

    Shorttle, O.; Moussallam, Y.; Hartley, M. E.; Edmonds, M.; Maclennan, J.; Murton, B. J.

    2014-12-01

    Planetary differentiation has been driven by the Earth's giant convective system, which has been redistributing heat, volatile elements and myriad other chemical species for 4.5 billion years. A key exchange in this transport process is between the mantle and the atmosphere through the volcanic degassing of sulfur, carbon and hydrogen from silicate melts forming in the deep Earth. The speciation and mobility of volatile elements during silicate melting is modulated by the oceanic mantle's oxygen fugacity (fO2), which away from subduction zones has long been considered uniform. However, a recent study has challenged this paradigm with new measurements of ferric iron proportions (Fe3+/Fe) in glasses from mid-ocean ridge basalts (Cottrell & Kelley, 2013). These new results suggest mantle domains containing material recycled from the Earth's surface are more reducing than ambient mantle and contain high concentrations of carbon. The pervasive mantle heterogeneity well documented in other geochemical indices may therefore be systematically associated with changes in oxidation state In this study we have produced a dataset of combined XANES, volatile element (C, S, F, Cl, H, B) and boron isotope analyses of 65 basalts from the Mid-Atlantic Ridge south of Iceland. These samples form a transect from 1000 km south of the Iceland plume to within 300 km of the plume centre, crossing into the zone experiencing the greatest geophysical and geochemical influence from the plume. Accordingly there are major changes in the isotopic and trace element composition of the basalts in this sample set, driven by both an increase in the proportion of recycled oceanic crustal components towards Iceland and a shift to a plume driven flow field. This suite of basalts therefore form an excellent test of the global correlations observed by Cottrell & Kelley (2013), where ferric iron contents anti-correlated with isotopic enrichment, with a high resolution regional dataset. By combining major element, volatile element and boron isotope data we have also interrogated the role of magmatic processes such as assimilation and degassing in influencing magmatic redox state. References: E. Cottrell & K. A. Kelley, Science, 340:1314 2013.

  14. The Self-Assembled Nanophase Particle (SNAP) Process: A Nanoscience Approach to Coatings

    SciTech Connect

    Donley, Michael S.; Mantz, Robert A.; Khramov, A. N.; Balbyshev, Vsevolod; Kasten, Linda S.; Gaspar, Dan J.

    2003-09-15

    In the corrosion protection of aluminum-skinned aircraft, surface pretreatment and cleaning are critical steps in protecting aerospace alloys from corrosion. Our recent discovery of a revolutionary new method of forming functionalized silica nanoparticles in situ in an aqueous-based sol-gel process, and then crosslinking the nanoparticles to form a thin film, is an excellent example of a nanoscience approach to coatings. This coating method is called the self-assembled nanophase particle (SNAP) process. The SNAP coating process consists of three stages: (1) sol-gel processing; (2) SNAP solution mixing; (3) SNAP coating application and cure. Here, we report on key parameters in the ''sol-gel processing'' and the ''coating application and cure'' stages in the GPTMS/TMOS system. The SNAP process is discussed from the formation of the nanosized macromolecules to the coating application and curing process. The ''sol-gel processing'' stage involves hydrolysis and condensation reactions and is controlled by the solution pH and water content. Here, the molar ratio of water to hydrolysable silane is a key factor. SNAP solutions have been investigated by NMR, IR, light scattering, and GPC to identify molecular condensation structures formed as a function of aging time in the solution. In moderate pH and highwater content solutions, hydrolysis occurs rapidly and condensation kinetic conditions are optimized to generate nanophase siloxane macromolecules. In the ''SNAP solution mixing'' stage, crosslinking agents and additives are added to the solution, which is then applied to a substrate by dip-coating to form the SNAP coating. The chemical structure and morphology of the films have been characterized using X-ray diffraction (XRD), time-of-flight secondary ion mass spectrometry (TOF-SIMS) and atomic force microscopy (AFM). SNAP films are amorphous but exhibit nanostructured assembly of siloxane oligomers at a separation of about 1.8 nm as well as molecular level ordering of O-Si-O species. The surface analytical data indicate that the films retain the basic chemical arrangement of the siloxane macromolecules/oligomers and crosslinking process creates a network of siloxane oligomers tethered together. Results of these analyses are then used to construct a model of the SNAP coating.

  15. Enhanced organic pollutant removal influenced by activated-ferric-sludge.

    PubMed

    Xu, G R; Tang, J H; Li, G B; Spinosa, L

    2014-01-01

    The primary goal of this study was to compare the pollutant removal efficiency of the reactivated activated-ferric-sludge (AFS) with that of the activated sludge (AS). Most tested organic pollutants were preferably removed by reactivated AFS. The optimal reactivated conditions for AFS were a reactivation time of 3 h, pH of 5-9, AFS dose of 5 g/L and dissolved oxygen of 2-6 mg/L. The results revealed a positive correlation between microbial activity and the removal efficiency of organic pollutants, with a higher microbial activity being associated with a better removal efficiency of organic pollutants. Additionally, variations in extracellular polymeric substances were found to be crucial to the microbial activity and adsorption capacity of reactivated AFS. After reactivation, reactivated AFS was superior to AS for the removal ofmost pollutants. Finally, the mechanism of AFS reactivation was investigated. Overall, the results of the present study demonstrate that reactivated AFS has the potential for widespread application in the removal of organic pollutants during the wastewater treatment process. PMID:25145208

  16. Exfoliation of Hexagonal Boron Nitride via Ferric Chloride Intercalation

    NASA Technical Reports Server (NTRS)

    Hung, Ching-cheh; Hurst, Janet; Santiago, Diana; Rogers, Richard B.

    2014-01-01

    Sodium fluoride (NaF) was used as an activation agent to successfully intercalate ferric chloride (FeCl3) into hexagonal boron nitride (hBN). This reaction caused the hBN mass to increase by approx.100 percent, the lattice parameter c to decrease from 6.6585 to between 6.6565 and 6.6569 ?, the x-ray diffraction (XRD) (002) peak to widen from 0.01deg to 0.05deg of the full width half maximum value, the Fourier transform infrared (FTIR) spectrum's broad band (1277/cm peak) to change shape, and new FTIR bands to emerge at 3700 to 2700 and 1600/cm. This indicates hBN's structural and chemical properties are significantly changed. The intercalated product was hygroscopic and interacted with moisture in the air to cause further structural and chemical changes (from XRD and FTIR). During a 24-h hold at room temperature in air with 100 percent relative humidity, the mass increased another 141 percent. The intercalated product, hydrated or not, can be heated to 750 C in air to cause exfoliation. Exfoliation becomes significant after two intercalation-air heating cycles, when 20-nm nanosheets are commonly found. Structural and chemical changes indicated by XRD and FTIR data were nearly reversed after the product was placed in hydrochloric acid (HCl), resulting in purified, exfoliated, thin hBN products.

  17. Ferric Phosphate Hydroxide Microstructures Affect Their Magnetic Properties

    PubMed Central

    Zhao, Junhong; Zhang, Youjuan; Run, Zhen; Li, Pengwei; Guo, Qifei; Pang, Huan

    2015-01-01

    Uniformly sized and shape-controlled nanoparticles are important due to their applications in catalysis, electrochemistry, ion exchange, molecular adsorption, and electronics. Several ferric phosphate hydroxide (Fe4(OH)3(PO4)3) microstructures were successfully prepared under hydrothermal conditions. Using controlled variations in the reaction conditions, such as reaction time, temperature, and amount of hexadecyltrimethylammonium bromide (CTAB), the crystals can be grown as almost perfect hyperbranched microcrystals at 180 °C (without CTAB) or relatively monodisperse particles at 220 °C (with CTAB). The large hyperbranched structure of Fe4(OH)3(PO4)3 with a size of ∼19 μm forms with the “fractal growth rule” and shows many branches. More importantly, the magnetic properties of these materials are directly correlated to their size and micro/nanostructure morphology. Interestingly, the blocking temperature (TB) shows a dependence on size and shape, and a smaller size resulted in a lower TB. These crystals are good examples that prove that physical and chemical properties of nano/microstructured materials are related to their structures, and the precise control of the morphology of such functional materials could allow for the control of their performance. PMID:26246988

  18. Iron fortification of flour with a complex ferric orthophosphate

    SciTech Connect

    Hallberg, L.; Rossander-Hulthen, L.; Gramatkovski, E.

    1989-07-01

    The unexpectedly low bioavailability in humans of elemental iron powder prompted us to search for other Fe compounds suitable for Fe fortification of flour that fulfill the two requirements of insolubility in water (due to high water content of flour) and good bioavailability in humans. Systematic studies of compatibility, solubility, and bioavailability led to this study of a microcrystalline complex ferric orthophosphate (CFOP), Fe/sub 3/H/sub 8/(NH/sub 4/)-(PO/sub 4/)6.6H/sub 2/O, a well-defined compound. This compound was labeled with /sup 59/Fe, and the native Fe in meals was labeled with /sup 55/FeCl3. The ratio of absorbed /sup 59/Fe to absorbed /sup 55/Fe is a direct measure of the fraction of CFOP that joins the nonheme Fe pool and that is made potentially available for absorption. The relative bioavailability of CFOP varied from 30% to 60% when labeled wheat rolls were served with different meals. The CFOP meets practical requirements of an Fe fortificant for flour well, with regard to both compatibility and bioavailability in humans.

  19. Effects of albumin and adenosine phosphates on iron transfer from ferric lactate.

    PubMed

    Anghileri, L J; Maincent, P; Crdova-Martnez, A; Escanero, J F

    1994-01-01

    Ferric lactate is known to modify Ca2+ uptake by the cells. To enlighten the role of protein and ATP in this phenomenon, iron transfer from ferric lactate to albumin and adenosine polyphosphates was determined by electrophoresis. The order of iron affinity was ATP > ADP > AMP for the polyphosphates, and albumin does not compete for iron binding with the polyphosphates. The iron transfer to ATP was also observed in vivo by adsorption chromatography of the adenosine polyphosphates fraction from blood plasma of mice injected with ferric lactate plus ATP. In vitro iron and calcium uptake by Ehrlich ascites tumor cells showed that albumin and ATP decreased iron uptake, whereas calcium incorporation is diminished by albumin but augmented by ATP. This difference might be explained by albumin binding of ferric lactate that is inhibited from reaching cell structures, whereas ATP, known to be an inhibitor of iron polymerization, facilitates it. PMID:7511923

  20. 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

  1. A micronised, dispersible ferric pyrophosphate with high relative bioavailability in man.

    PubMed

    Fidler, Meredith C; Walczyk, Thomas; Davidsson, Lena; Zeder, Christophe; Sakaguchi, Noboru; Juneja, Lekh R; Hurrell, Richard F

    2004-01-01

    Ferric pyrophosphate is a water-insoluble Fe compound used to fortify infant cereals and chocolate-drink powders as it causes no organoleptic changes to the food vehicle. However, it is only of low absorption in man. Recently, an innovative ferric pyrophosphate has been developed (Sunactive Fe trade mark ) based on small-particle-size ferric pyrophosphate (average size 0.3 microm) mixed with emulsifiers, so that it remains in suspension in liquid products. The aim of the present studies was to compare Fe absorption of micronised, dispersible ferric pyrophosphate (Sunactive Fe trade mark ) with that of ferrous sulfate in an infant cereal and a yoghurt drink. Two separate Fe absorption studies were made in adult women (ten women/study). Fe absorption was based on the erythrocyte incorporation of stable isotopes ((57)Fe and (58)Fe) 14 d after the intake of labelled test meals of infant cereal (study 1) or yoghurt drink (study 2). Each test meal was fortified with 5 mg Fe as ferrous sulfate or micronised, dispersible ferric pyrophosphate. Results are presented as geometric means. There was no statistically significant difference between Fe absorption from micronised, dispersible ferric pyrophosphate- and ferrous sulfate-fortified infant cereal (3.4 and 4.1 % respectively; P=0.24) and yoghurt drink (3.9 and 4.2 % respectively; P=0.72). The results of the present studies show that micronised, dispersible ferric pyrophosphate is as well absorbed as ferrous sulfate in adults. The high relative Fe bioavailability of micronised, dispersible ferric pyrophosphate indicates the potential usefulness of this compound for food fortification. PMID:14748943

  2. Demonstration of ferric L-parabactin-binding activity in the outer membrane of Paracoccus denitrificans.

    PubMed Central

    Bergeron, R J; Weimar, W R; Dionis, J B

    1988-01-01

    Under low-iron conditions, Paracoccus denitrificans excretes a catecholamine siderophore, L-parabactin, to sequester and utilize iron. In this report, we demonstrate the presence of stereospecific high-affinity ferric L-parabactin-binding activity associated with P. denitrificans membranes grown in low-iron medium. Isolated outer membrane components were shown to be three to four times higher in specific activity for ferric L-parabactin. The same amount of binding activity existed whether or not the radiolabel was present in the metal (55Fe) or the ligand (3H) portion of ferric parabactin chelate, suggesting that binding was to the intact complex. Ion-exchange chromatography of a Triton X-100-solubilized outer membrane mixture on DEAE-cellulose resulted in a 10-fold increase in binding activity relative to that present in whole membranes. Polypeptide profiles by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the products of each stage of the purification showed that binding activity copurified with one or more of the low-iron-induced outer membrane proteins in the 80-kilodalton (kDa) region. Membrane proteins and [55Fe]ferric L-parabactin electrophoresed in nondenaturing gels demonstrated the presence of membrane component(s) which stereo-specifically bound ferric L-parabactin, thus providing independent confirmation of the binding assay results. Moreover, when the band labeled by [55Fe]ferric L-parabactin was excised and profiled by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, 80-kDa polypeptides were the major components present. These results demonstrate the presence of a high-affinity ferric L-parabactin receptor in P. denitrificans membranes and suggest that one or more of the 80-kDa low-iron-induced polypeptides are components of the ferric L-parabactin receptor. Images PMID:3403511

  3. Mechanistic insights on the ortho-hydroxylation of aromatic compounds by non-heme iron complex: a computational case study on the comparative oxidative ability of ferric-hydroperoxo and high-valent Fe(IV)?O and Fe(V)?O intermediates.

    PubMed

    Ansari, Azaj; Kaushik, Abhishek; Rajaraman, Gopalan

    2013-03-20

    ortho-Hydroxylation of aromatic compounds by non-heme Fe complexes has been extensively studied in recent years by several research groups. The nature of the proposed oxidant varies from Fe(III)-OOH to high-valent Fe(IV)?O and Fe(V)?O species, and no definitive consensus has emerged. In this comprehensive study, we have investigated the ortho-hydroxylation of aromatic compounds by an iron complex using hybrid density functional theory incorporating dispersion effects. Three different oxidants, Fe(III)-OOH, Fe(IV)?O, and Fe(V)?O, and two different pathways, H-abstraction and electrophilic attack, have been considered to test the oxidative ability of different oxidants and to underpin the exact mechanism of this regiospecific reaction. By mapping the potential energy surface of each oxidant, our calculations categorize Fe(III)-OOH as a sluggish oxidant, as both proximal and distal oxygen atoms of this species have prohibitively high barriers to carry out the aromatic hydroxylation. This is in agreement to the experimental observation where Fe(III)-OOH is found not to directly attack the aromatic ring. A novel mechanism for the explicit generation of non-heme Fe(IV)?O and Fe(V)?O from isomeric forms of Fe(III)-OOH has been proposed where the OO bond is found to cleave via homolytic (Fe(IV)?O) or heterolytic (Fe(V)?O) fashion exclusively. Apart from having favorable formation energies, the Fe(V)?O species also has a lower barrier height compared to the corresponding Fe(IV)?O species for the aromatic ortho-hydroxylation reaction. The transient Fe(V)?O prefers electrophilic attack on the benzene ring rather than the usual aromatic C-H activation step. A large thermodynamic drive for the formation of a radical intermediate is encountered in the mechanistic scene, and this intermediate substantially diminishes the energy barrier required for C-H activation by the Fe(V)?O species. Further spin density distribution and the frontier orbitals of the computed species suggest that the Fe(IV)?O species has a substantial barrier height for this reaction, as the substrate is coordinated to the metal atoms. This coordination restricts the C-H activation step by Fe(IV)?O species to proceed via the ?-type pathway, and thus the usual energy lowering due to the low-lying quintet state is not observed here. PMID:23373840

  4. Structure and Growth of Quasi One-Dimensional YSi2 Nanophases on Si(100)

    PubMed Central

    Iancu, V.; Kent, P.R.C.; Hus, S.; Hu, H.; Zeng, C.G.; Weitering, H.H.

    2013-01-01

    Quasi one-dimensional YSi2 nanostructures are formed via self-assembly on the Si(100) surface. These epitaxial nanowires are metastable and their formation strongly depends on the growth parameters. Here, we explore the various stages of yttrium silicide formation over a range of metal coverages and growth temperatures, and establish a rudimentary phase diagram for these novel and often coexisting nanophases. In addition to previously identified stoichiometric wires, we identify several new nanowire systems. These nanowires exhibit a variety of surface reconstructions, which sometimes coexist on a single wire. From a comparison of scanning tunneling microcopy images, tunneling spectra, and first-principles density functional theory calculations, we determine that these surface reconstructions arise from local orderings of yttrium vacancies. Nanowires often agglomerate into nanowire bundles, the thinnest of which are formed by single wire pairs. The calculations show that such bundles are energetically favored compared to well-separated single wires. Thicker bundles are formed at slightly higher temperature. They extend over several microns, forming a robust network of conducting wires that could possibly be employed in nanodevice applications. PMID:23221350

  5. Side chain crystallization and non-equilibrium phenomena in nanophase separated poly(3-alkyl thiophenes)

    NASA Astrophysics Data System (ADS)

    Pankaj, Shireesh; Beiner, Mario

    2010-06-01

    A series of regio-random poly(3-alkyl thiophenes) containing C = 6-12 carbon atoms per side chain is studied using shear, calorimetry and x-ray scattering methods. Dynamic and structural data indicate a nanophase separation of thiophene main chains and alkyl groups. Alkyl nanodomains of size of 1-3 nm are formed as indicated by pre-peaks in scattering data at 0.2-1?q?0.6-1. Apart from the conventional ? relaxation, an additional ?PE process appears at low temperatures reflecting an independent dynamics within the alkyl nanodomains. The influence of slow side chain crystallization and densification processes during physical aging below Tg on the relaxation behavior is studied. Long term experiments show that short alkyl groups do not crystallize, whereas for longer alkyl groups, side chain crystallization is occurring but hindered by immobile and rigid main chains. Slow side chain crystallization processes are indicated in poly(3-decyl thiophene) and poly(3-dodecyl thiophene) by melting peaks in DSC scans, a decreasing ?PE intensity and an increase in the plateau modulus. Isothermal crystallization experiments on these samples show that the alkyl groups can exist in different polymorphic states.

  6. Nanophase iron production through laser irradiation and magnetic detection of space weathering analogs

    NASA Astrophysics Data System (ADS)

    Markley, Matthew; Kletetschka, Gunther

    2016-04-01

    Airless bodies are constantly exposed to space weathering. The Moon and other similar S-type asteroids physically change through comminution, melting, and agglutinate formation, while spectrally they are darkening, steepening (or reddening) the spectral slope toward longer wavelengths, and reducing silicate mineral absorption bands. In these S-type bodies the production of submicroscopic metallic iron, or nanophase iron (SMFe, npFe0) is a major contributor in these spectral changes. We made a qualitative estimate of both quantity and size distribution of produced metallic iron by space weathered analog, olivine irradiated by laser. Through SEM observation we confirmed that nanoparticles of metallic iron formed in the nm range. Spectroscopic and magnetic susceptibility (MS) through temperature analyses reveal an increasing trend of npFe0 formation, darkening, reddening, and shallowing of the 1 μm olivine absorption band. Olivine that produced the larger end of the size range of npFe0 produced similar effects, except for increased reddening. The magnetic data suggests that with laser irradiation there is both a linear increase of nanoparticles and a logarithmic increase in spectral change with SW time.

  7. Ferric-Pyoverdine Recognition by Fpv Outer Membrane Proteins of Pseudomonas protegens Pf-5

    PubMed Central

    Hartney, Sierra L.; Mazurier, Sylvie; Girard, Mava K.; Mehnaz, Samina; Davis, Edward W.; Gross, Harald; Lemanceau, Philippe

    2013-01-01

    The soil bacterium Pseudomonas protegens Pf-5 (previously called P. fluorescens Pf-5) produces two siderophores, enantio-pyochelin and a compound in the large and diverse pyoverdine family. Using high-resolution mass spectroscopy, we determined the structure of the pyoverdine produced by Pf-5. In addition to producing its own siderophores, Pf-5 also utilizes ferric complexes of some pyoverdines produced by other strains of Pseudomonas spp. as sources of iron. Previously, phylogenetic analysis of the 45 TonB-dependent outer membrane proteins in Pf-5 indicated that six are in a well-supported clade with ferric-pyoverdine receptors (Fpvs) from other Pseudomonas spp. We used a combination of phylogenetics, bioinformatics, mutagenesis, pyoverdine structural determinations, and cross-feeding bioassays to assign specific ferric-pyoverdine substrates to each of the six Fpvs of Pf-5. We identified at least one ferric-pyoverdine that was taken up by each of the six Fpvs of Pf-5. Functional redundancy of the Pf-5 Fpvs was also apparent, with some ferric-pyoverdines taken up by all mutants with a single Fpv deletion but not by a mutant having deletions in two of the Fpv-encoding genes. Finally, we demonstrated that phylogenetically related Fpvs take up ferric complexes of structurally related pyoverdines, thereby establishing structure-function relationships that can be employed in the future to predict the pyoverdine substrates of Fpvs in other Pseudomonas spp. PMID:23222724

  8. Biogenic catalysis of soil formation on Mars?

    NASA Technical Reports Server (NTRS)

    Bishop, J. L.

    1998-01-01

    The high iron abundance and the weak ferric iron spectral features of martian surface material are consistent with nanophase (nm-sized) iron oxide minerals as a major source of iron in the bright region soil on Mars. Nanophase iron oxide minerals, such as ferrihydrite and schwertmannite, and nanophase forms of hematite and goethite are formed by both biotic and abiotic processes on Earth. The presence of these minerals on Mars does not indicate biological activity on Mars, but it does raise the possibility. This work includes speculation regarding the possibility of biogenic soils on Mars based on previous observations and analyses. A remote sensing goal of upcoming missions should be to determine if nanophase iron oxide minerals, clay silicates and carbonates are present in the martian surface material. These minerals are important indicators for exobiology and their presence on Mars would invoke a need for further investigation and sample return from these sites.

  9. Biogenic catalysis of soil formation on Mars?

    PubMed

    Bishop, J L

    1998-10-01

    The high iron abundance and the weak ferric iron spectral features of martian surface material are consistent with nanophase (nm-sized) iron oxide minerals as a major source of iron in the bright region soil on Mars. Nanophase iron oxide minerals, such as ferrihydrite and schwertmannite, and nanophase forms of hematite and goethite are formed by both biotic and abiotic processes on Earth. The presence of these minerals on Mars does not indicate biological activity on Mars, but it does raise the possibility. This work includes speculation regarding the possibility of biogenic soils on Mars based on previous observations and analyses. A remote sensing goal of upcoming missions should be to determine if nanophase iron oxide minerals, clay silicates and carbonates are present in the martian surface material. These minerals are important indicators for exobiology and their presence on Mars would invoke a need for further investigation and sample return from these sites. PMID:9742725

  10. Transmission electron microscopy and electron holography of nanophase TiO{sub 2} generated in a flame burner system

    SciTech Connect

    Turner, S.; Bonevich, J.E.; Maslar, J.E.; Aquino, M.I.; Zachariah, M.R.

    1997-09-01

    Nanophase TiO{sub 2} (n-TiO{sub 2}) particles were generated in a flame burner system under three experimental conditions. Selected individual nanoparticles were identified and characterized using selected area electron diffraction, bright-field and, in some cases, dark-field imaging to determine morphology and microstructural features. Previously unknown TiO{sub 2} particles with unusual central features were identified as rutile. Electron holography was used to characterize the central features which were found to be consistent with voids. More extensive characterization of individual particles may lead to improved understanding of n-TiO{sub 2} nucleation and growth.

  11. Aggregation in complex triacylglycerol oils: coarse-grained models, nanophase separation, and predicted x-ray intensities

    NASA Astrophysics Data System (ADS)

    Quinn, Bonnie; Peyronel, Fernanda; Gordon, Tyler; Marangoni, Alejandro; Hanna, Charles B.; Pink, David A.

    2014-11-01

    Triacylglycerols (TAGs) are biologically important molecules which form crystalline nanoplatelets (CNPs) and, ultimately, fat crystal networks in edible oils. Characterizing the self-assembled hierarchies of these networks is important to understanding their functionality and oil binding capacity. We have modelled CNPs in multicomponent oils and studied their aggregation. The oil comprises (a) a liquid componentt, and (b) components which phase separately on a nano-scale (nano-phase separation) to coat the surfaces of the CNPs impenetrably, either isotropically or anisotropically, with either liquid-like coatings or crystallites, forming a coating of thickness Δ. We modelled three cases: (i) liquid-liquid nano-phase separation, (ii) solid-liquid nano-phase separation, with CNPs coated isotropically, and (iii) CNPs coated anisotropically. The models were applied to mixes of tristearin and triolein with fully hydrogenated canola oil, shea butter with high oleic sunflower oil, and cotton seed oil. We performed Monte Carlo simulations, computed structure functions and concluded: (1) three regimes arose: (a) thin coating regime, Δ \\lt 0.0701 u (b) transition regime, 0.0701 u≤slant Δ ≤slant 0.0916 u and (c) thick coating regime, Δ \\gt 0.0916 u . (arbitrary units, u) (2) The thin coating regime exhibits 1D TAGwoods, which aggregate, via DLCA/RLCA, into fractal structures which are uniformly distributed in space. (3) In the thick coating regime, for an isotropic coating, TAGwoods are not formed and coated CNPs will not aggregate but will be uniformly distributed in space. For anisotropic coating, TAGwoods can be formed and might form 1D strings but will not form DLCA/RLCA clusters. (4) The regimes are, approximately: thin coating, 0\\lt Δ \\lt 7.0 \\text{nm} transition regime, 7.0\\ltΔ \\lt 9.2 \\text{nm} and thick coating, Δ \\gt 9.2 \\text{nm} (5) The minimum minority TAG concentration required to undergo nano-phase separation is, approximately, 0.29% (thin coatings) and 0.94% (thick coatings). Minority components can have substantial effects upon aggregation for concentrations less than 1%.

  12. Aggregation in complex triacylglycerol oils: coarse-grained models, nanophase separation, and predicted x-ray intensities.

    PubMed

    Quinn, Bonnie; Peyronel, Fernanda; Gordon, Tyler; Marangoni, Alejandro; Hanna, Charles B; Pink, David A

    2014-11-19

    Triacylglycerols (TAGs) are biologically important molecules which form crystalline nanoplatelets (CNPs) and, ultimately, fat crystal networks in edible oils. Characterizing the self-assembled hierarchies of these networks is important to understanding their functionality and oil binding capacity. We have modelled CNPs in multicomponent oils and studied their aggregation. The oil comprises (a) a liquid component, and (b) components which phase separately on a nano-scale (nano-phase separation) to coat the surfaces of the CNPs impenetrably, either isotropically or anisotropically, with either liquid-like coatings or crystallites, forming a coating of thickness ?. We modelled three cases: (i) liquid?liquid nano-phase separation, (ii) solid?liquid nano-phase separation, with CNPs coated isotropically, and (iii) CNPs coated anisotropically. The models were applied to mixes of tristearin and triolein with fully hydrogenated canola oil, shea butter with high oleic sunflower oil, and cotton seed oil. We performed Monte Carlo simulations, computed structure functions and concluded: (1) three regimes arose: (a) thin coating regime, ? < 0.0701 u (b) transition regime, 0.0701 u ? ? ? 0.0916 u and (c) thick coating regime, ? > 0.0916 u. (arbitrary units, u) (2) The thin coating regime exhibits 1D TAGwoods, which aggregate, via DLCA/RLCA, into fractal structures which are uniformly distributed in space. (3) In the thick coating regime, for an isotropic coating, TAGwoods are not formed and coated CNPs will not aggregate but will be uniformly distributed in space. For anisotropic coating, TAGwoods can be formed and might form 1D strings but will not form DLCA/RLCA clusters. (4) The regimes are, approximately: thin coating, 0 < ? < 7.0 nm transition regime, 7.0 < ? < 9.2 nm and thick coating, ? > 9.2 nm (5) The minimum minority TAG concentration required to undergo nano-phase separation is, approximately, 0.29% (thin coatings) and 0.94% (thick coatings). Minority components can have substantial effects upon aggregation for concentrations less than 1%. PMID:25347720

  13. Liposome as a delivery system for carotenoids: comparative antioxidant activity of carotenoids as measured by ferric reducing antioxidant power, DPPH assay and lipid peroxidation.

    PubMed

    Tan, Chen; Xue, Jin; Abbas, Shabbar; Feng, Biao; Zhang, Xiaoming; Xia, Shuqin

    2014-07-16

    This study was conducted to understand how carotenoids exerted antioxidant activity after encapsulation in a liposome delivery system, for food application. Three assays were selected to achieve a wide range of technical principles, including 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging, ferric reducing antioxidant powder (FRAP), and lipid peroxidation inhibition capacity (LPIC) during liposome preparation, auto-oxidation, or when induced by ferric iron/ascorbate. The antioxidant activity of carotenoids was measured either after they were mixed with preformed liposomes or after their incorporation into the liposomal system. Whatever the antioxidant model was, carotenoids displayed different antioxidant activities in suspension and in liposomes. The encapsulation could enhance the DPPH scavenging and FRAP activities of carotenoids. The strongest antioxidant activity was observed with lutein, followed by ?-carotene, lycopene, and canthaxanthin. Furthermore, lipid peroxidation assay revealed a mutually protective relationship: the incorporation of either lutein or ?-carotene not only exerts strong LPIC, but also protects them against pro-oxidation elements; however, the LPIC of lycopene and canthaxanthin on liposomes was weak or a pro-oxidation effect even appeared, concomitantly leading to the considerable depletion of these encapsulated carotenoids. The antioxidant activity of carotenoids after liposome encapsulation was not only related to their chemical reactivity, but also to their incorporation efficiencies into liposomal membrane and modulating effects on the membrane properties. PMID:24745755

  14. Quantitative determination of cesium binding to ferric hexacyanoferrate: Prussian blue.

    PubMed

    Faustino, Patrick J; Yang, Yongsheng; Progar, Joseph J; Brownell, Charles R; Sadrieh, Nakissa; May, Joan C; Leutzinger, Eldon; Place, David A; Duffy, Eric P; Houn, Florence; Loewke, Sally A; Mecozzi, Vincent J; Ellison, Christopher D; Khan, Mansoor A; Hussain, Ajaz S; Lyon, Robbe C

    2008-05-12

    Ferric hexacyanoferrate (Fe4III[FeII(CN)6]3), also known as insoluble Prussian blue (PB) is the active pharmaceutical ingredient (API) of the drug product, Radiogardase. Radiogardase is the first FDA approved medical countermeasure for the treatment of internal contamination with radioactive cesium (Cs) or thallium in the event of a major radiological incident such as a "dirty bomb". A number of pre-clinical and clinical studies have evaluated the use of PB as an investigational decorporation agent to enhance the excretion of metal cations. There are few sources of published in vitro data that detail the binding capacity of cesium to insoluble PB under various chemical and physical conditions. The study objective was to determine the in vitro binding capacity of PB APIs and drug products by evaluating certain chemical and physical factors such as medium pH, particle size, and storage conditions (temperature). In vitro experimental conditions ranged from pH 1 to 9, to cover the range of pH levels that PB may encounter in the gastrointestinal (GI) tract in humans. Measurements of cesium binding were made between 1 and 24h, to cover gastric and intestinal tract residence time using a validated atomic emission spectroscopy (AES) method. The results indicated that pH, exposure time, storage temperature (affecting moisture content) and particle size play significant roles in the cesium binding to both the PB API and the drug product. The lowest cesium binding was observed at gastric pH of 1 and 2, whereas the highest cesium binding was observed at physiological pH of 7.5. It was observed that dry storage conditions resulted in a loss of moisture from PB, which had a significant negative effect on the PB cesium binding capacity at time intervals consistent with gastric residence. Differences were also observed in the binding capacity of PB with different particle sizes. Significant batch to batch differences were also observed in the binding capacity of some PB API and drug products. Our results suggest that certain physiochemical properties affect the initial binding capacity and the overall binding capacity of PB APIs and drug products during conditions that simulated gastric and GI residence time. These physiochemical properties can be utilized as quality attributes to monitor and predict drug product quality under certain manufacturing and storage conditions and may be utilized to enhance the clinical efficacy of PB. PMID:18242038

  15. Quantitative determination of thallium binding to ferric hexacyanoferrate: Prussian blue.

    PubMed

    Yang, Yongsheng; Faustino, Patrick J; Progar, Joseph J; Brownell, Charles R; Sadrieh, Nakissa; May, Joan C; Leutzinger, Eldon; Place, David A; Duffy, Eric P; Yu, Lawrence X; Khan, Mansoor A; Lyon, Robbe C

    2008-04-01

    Ferric hexacyanoferrate, (Fe(4)(III)[Fe(II)(CN)(6)](3)), also known as insoluble Prussian blue (PB), is the active pharmaceutical ingredient (API) of Radiogardase which is the first approved drug product (DP) for treatment of thallium and radiocesium poisoning. The aim of this study is (1) to determine the in vitro thallium binding capacity and binding rates of insoluble PB; and (2) to evaluate the effect of physiological pH conditions, PB particle size and storage conditions on the binding to PB. Experimental pH levels from 1.0 to 7.5 were used to cover the range of pH levels that PB may encounter when traveling through the gastrointestinal (GI) tract in humans. Measurements of thallium binding were made between 1 and 24h, to cover gastric and intestinal tract residence time. PB was found to have a binding capacity of approximately 1400 mg/g at pH 7.5. When the pH decreased, the binding decreased as well. The results indicated that the hydration state of PB influences the thallium binding process. It was also found that there exits a direct correlation between the moisture loss in PB and the thallium binding rate constant. The PB with 17 mol of water had a binding rate constant of 0.52, which was reduced to 0.32 when PB was dehydrated to 2.5 mol of water. Significant differences were observed in both binding capacity and binding rate constant among PB fractions with different particle size ranges. PB fraction with particle size of 220-1000 microm had a binding rate constant of 0.43, which increased to 0.64 when the particle size was reduced to 32-90 microm. Batch-to-batch variation in thallium binding was also observed among the APIs and the DPs and this was related to particle size and hydration state. These findings can be utilized to evaluate and predict drug product quality under certain manufacturing and dry storage conditions. PMID:18226478

  16. Effects of manganese and ferric iron on Fe-Mg mixing in garnet and biotite

    SciTech Connect

    Williams, M.L.; Grambling, J.A.

    1985-01-01

    The distribution of Fe and Mg between biotite and garnet is complicated by factors such as non-ideal mixing in garnet and the presence of ferric iron, not measurable by microprobe analysis, in biotite. The effects of these factors have been obscured by the larger scatter typically inherent in garnet-biotite KD measurements. This scatter can be significantly reduced by compositional mapping of garnet using 2-10/mu/ analysis intervals to resolve fine-scale zoning features, and by the elimination of biotite analyses that suggest incipient alteration. In a large suite of low-Ca garnet-biotite pairs from northern New Mexico, biotite has negligible Mn and a negative correlation exists between XMn, gar and KD for garnets with XMn less than 0.4. The data are consistent with minor non-ideal mixing of Mn in garnet (WMn = 1000 cal) and ideal mixing of Mg, Fe, and Ti in both garnet and biotite. An alternate interpretation is suggested by a linear relationship that exists between XMn and (XFe-XMg) in garnet. This relationship allows the possibility that Mn mixes more non-ideally in garnet, with this effect precisely counterbalanced by non-ideal Fe-Mg mixing in garnet. Further work is in progress to evaluate these two alternatives. At XMn near 0.4, the correlation between KD and XMn switches from negative to positive. This change apparently reflects increasing substitution of Fe/sup 3+/ into biotite. Oxide minerals document that oxygen fugacity increases as XMn,gar increases, and preliminary wet chemical analyses of biotite separates confirm that Fe/sup 3+//Fe/sup 2+/ in biotite increases with XMn in garnet.

  17. Thermally altered palagonitic tephra - A spectral and process analog to the soil and dust of Mars

    NASA Technical Reports Server (NTRS)

    Bell, James F., III; Morris, Richard V.; Adams, John B.

    1993-01-01

    Six palagonitic soil samples (PH-1 through PH-6) which were collected at 30-cm intervals from a lava slab on Mauna Kea, Hawaii, are studied. The samples present an alteration sequence caused by heating during emplacement of molten lava over a preexisting tephra cone. Techniques employed include visible and near-IUR spectroscopy, Moessbauer spectroscopy, and magnetic analysis. The four samples closest to the slab (PH-1 through PH-4) were strongly altered in response to heating during its emplacement; their iron oxide mineralogy is dominated by nanophase ferric oxide. The sample adjacent to the slab (PH-1) has a factor of 3 less H2O and contains crystalline hematite and magnetite in addition to nanophase ferric oxide. It is argued that localized thermal alteration events may provide a volumetrically important mechanism for the palagonitization of basaltic glass and the production of crystalline ferric oxides on Mars.

  18. Vibrational Dynamics of Ferric MbCN-A Revisit by Resonance Raman and Vibrational Coherence Spectroscopy

    NASA Astrophysics Data System (ADS)

    Zeng, Weiqiao; Sun, Yuhan; Benabbas, Abdelkrim; Champion, Paul M.

    2012-02-01

    Ultrafast pump-probe spectroscopy has indicated that there exists a photoproduct state following the excitation of ferric MbCN^[1][2]. This excited state decays with a time constant of 3.6 ps^[1]. Previous studies on this system have suggested that in this photoproduct state, the heme is either (i) still six-coordinated but vibrationally hot in the electronic ground state^[1] or (ii) the proximal histidine residue (His93) is transiently dissociated, while CN^- is still bound^[2]. Recent resonance Raman measurements on ferric MbCN in static solution yield spectra that are very similar to ferric myoglobin, which has His93 and a water molecule as axial ligands. This indicates that a water molecule replaces CN^- in ferric MbCN under continuous laser excitation. Photolysis of CN^- from the heme iron is necessary to make this happen, which is not consistent with the above two suggestions. In this presentation we will revisit the dynamics of ferric MbCN with resonance Raman and vibrational coherence spectroscopy and try to explain how a water molecule competes with CN^- in binding to the heme under photo excitation^[3]. References: [1]Helbing J. et al., Biophys J, vol 87, 1881(2004) [2]Gruia F. et al., Biophys J, vol 94, 2252(2008) [3]Cao W. et al., Biochemistry, vol 40, 5728(2001)

  19. A Cytochrome b561 with Ferric Reductase Activity from the Parasitic Blood Fluke, Schistosoma japonicum

    PubMed Central

    Glanfield, Amber; McManus, Donald P.; Smyth, Danielle J.; Lovas, Erica M.; Loukas, Alex; Gobert, Geoffrey N.; Jones, Malcolm K.

    2010-01-01

    Background Iron has an integral role in numerous cellular reactions and is required by virtually all organisms. In physiological conditions, iron is abundant in a largely insoluble ferric state. Ferric reductases are an essential component of iron uptake by cells, reducing iron to the soluble ferrous form. Cytochromes b561 (cyts-b561) are a family of ascorbate reducing transmembrane proteins found in most eukaryotic cells. The identification of the ferric reductase duodenal cytochrome b (dcytb) and recent observations that other cyts-b561 may be involved in iron metabolism have opened novel perspectives for elucidating their physiological function. Methodology/Principal Findings Here we have identified a new member of the cytochrome b561 (Sjcytb561) family in the pathogenic blood fluke Schistosoma japonicum that localises to the outer surface of this parasitic trematode. Heterologous expression of recombinant Sjcyt-b561 in a Saccharomyces cerevisiae mutant strain that lacks plasma membrane ferrireductase activity demonstrated that the molecule could rescue ferric reductase activity in the yeast. Significance/Conclusions This finding of a new member of the cytochrome b561 family further supports the notion that a ferric reductase function is likely for other members of this protein family. Additionally, the localisation of Sjcytb561 in the surface epithelium of these blood-dwelling schistosomes contributes further to our knowledge concerning nutrient acquisition in these parasites and may provide novel targets for therapeutic intervention. PMID:21103361

  20. 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.

  1. 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

  2. Chromium doped nano-phase separated yttria-alumina-silica glass based optical fiber preform: fabrication and characterization

    NASA Astrophysics Data System (ADS)

    Dutta, Debjit; Dhar, Anirban; Das, Shyamal; Bysakh, Sandip; Kir'yanov, Alexandar; Paul, Mukul Chandra

    2015-06-01

    Transition metal (TM) doping in silica core optical fiber is one of the research area which has been studied for long time and Chromium (Cr) doping specially attracts a lot of research interest due to their broad emission band covering U, C and L band with many potential application such as saturable absorber or broadband amplifier etc. This paper present fabrication of Cr doped nano-phase separated silica fiber within yttria-alumina-silica core glass through conventional Modified Chemical Vapor Deposition (MCVD) process coupled with solution doping technique along with different material and optical characterization. For the first time scanning electron microscope (SEM) / energy dispersive X-ray (EDX) analysis of porous soot sample and final preform has been utilized to investigate incorporation mechanism of Crions with special emphasis on Cr-species evaporation at different stages of fabrication. We also report that optimized annealing condition of our fabricated preform exhibited enhanced fluorescence emission and a broad band within 550- 800 nm wavelength region under pumping at 532 nm wavelength due to nano-phase restructuration.

  3. Nanophase cobalt, nickel and zinc ferrites: synchrotron XAS study on the crystallite size dependence of metal distribution.

    PubMed

    Nordhei, Camilla; Ramstad, Astrid Lund; Nicholson, David G

    2008-02-21

    Nanophase cobalt, nickel and zinc ferrites, in which the crystallites are in the size range 4-25 nm, were synthesised by coprecipitation and subsequent annealing. X-Ray absorption spectroscopy using synchrotron radiation (supported by X-ray powder diffraction) was used to study the effects of particle size on the distributions of the metal atoms over the tetrahedral and octahedral sites of the spinel structure. Deviations from the bulk structure were found which are attributed to the significant influence of the surface on very small particles. Like the bulk material, nickel ferrite is an inverse spinel in the nanoregime, although the population of metals on the octahedral sites increases with decreasing particle size. Cobalt ferrite and zinc ferrite take the inverse and normal forms of the spinel structure respectively, but within the nanoregime both systems show similar trends in being partially inverted. Further, in zinc ferrite, unlike the normal bulk structure, the nanophase system involves mixed coordinations of zinc(ii) and iron(iii) consistent with increasing partial inversion with size. PMID:18259645

  4. Microbial acquisition of iron from ferric iron bearing minerals

    SciTech Connect

    Hersman, L.E.; Sposito, G.

    1998-12-31

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

  5. Juvenile ferric iron prevents microbiota dysbiosis and colitis in adult rodents

    PubMed Central

    Ettreiki, Chourouk; Gadonna-Widehem, Pascale; Mangin, Irne; Coffier, Mose; Delayre-Orthez, Carine; Anton, Pauline M

    2012-01-01

    AIM: To assess whether juvenile chronic ferric iron ingestion limit colitis and dysbiosis at adulthood in rats and mice. METHODS: Two sets of experiments were designed. In the first set, recently weaned mice were either orally administered ferrous (Fe2+) iron salt or ferric (Fe3+) microencapsulated iron for 6 wk. The last week of experiments trinitrobenzene sulfonic acid (TNBS) colitis was induced. In the second set, juvenile rats received the microencapsulated ferric iron for 6 wk and were also submitted to TNBS colitis during the last week of experiments. In both sets of experiments, animals were sacrificed 7 d after TNBS instillation. Severity of the inflammation was assessed by scoring macroscopic lesions and quantifying colonic myeloperoxidase (MPO) activity. Alteration of the microflora profile was estimated using quantitative polymerase chain reaction (qPCR) by measuring the evolution of total caecal microflora, Bacteroidetes, Firmicutes and enterobacteria. RESULTS: Neither ferrous nor ferric iron daily exposures at the juvenile period result in any effect in control animals at adulthood although ferrous iron repeated administration in infancy limited weight gain. Ferrous iron was unable to limit the experimental colitis (1.71 0.27 MPO U/mg protein vs 2.47 0.22 MPO U/mg protein in colitic mice). In contrast, ferric iron significantly prevented the increase of MPO activity (1.64 0.14 MPO U/mg protein) in TNBS-induced colitis. Moreover, this positive effect was observed at both the doses of ferric iron used (75 and 150 mg/kg per day po - 6 wk). In the study we also compared, in both rats and mice, the consequences of chronic repeated low level exposure to ferric iron (75 mg/kg per day po - 6 wk) on TNBS-induced colitis and its related dysbiosis. We confirmed that ferric iron limited the TNBS-induced increase of MPO activity in both the rodent species. Furthermore, we assessed the ferric iron incidence on TNBS-induced intestinal microbiota dysbiosis. At first, we needed to optimize the isolation and quantify DNA copy numbers using standard curves to perform by qPCR this interspecies comparison. Using this approach, we determined that total microflora was similar in control rats and mice and was mainly composed of Firmicutes and Bacteroidetes at a ratio of 10/1. Ferric juvenile administration did not modify the microflora profile in control animals. Total microflora numbers remained unchanged whichever experimental conditions studied. Following TNBS-induced colitis, the Firmicutes/Bacteroidetes ratio was altered resulting in a decrease of the Firmicutes numbers and an increase of the Bacteroidetes numbers typical of a gut inflammatory reaction. In parallel, the subdominant population, the enterobacteria was also increased. However, ferric iron supplementation for the juvenile period prevented the increase of Bacteroidetes and of enterobacteria numbers consecutive to the colitis in both the studied species at adulthood. CONCLUSION: Rats and mice juvenile chronic ferric iron ingestion prevents colitis and dysbiosis at adulthood as assessed by the first interspecies comparison. PMID:22690070

  6. Uptake mechanisms for inorganic iron and ferric citrate in Trichodesmium erythraeum IMS101.

    PubMed

    Roe, Kelly L; Barbeau, Katherine A

    2014-11-01

    Growth of the prevalent marine organism Trichodesmium can be limited by iron in natural and laboratory settings. This study investigated the iron uptake mechanisms that the model organism T. erythraeum IMS101 uses to acquire iron from inorganic iron and iron associated with the weak ligand complex, ferric citrate. IMS101 was observed to employ two different iron uptake mechanisms: superoxide-mediated reduction of inorganic iron in the surrounding milieu and a superoxide-independent uptake system for ferric citrate complexes. While the detailed pathway of ferric citrate utilization remains to be elucidated, transport of iron from this complex appears to involve reduction and/or exchange of the iron out of the complex prior to uptake, either at the outer membrane of the cell or within the periplasmic space. Various iron uptake strategies may allow Trichodesmium to effectively scavenge iron in oligotrophic ocean environments. PMID:25222699

  7. Experimental Spinel Standards for Ferric Iron (Fe3+) Determination During Peridotite Partial Melting

    NASA Astrophysics Data System (ADS)

    Wenz, M. D.; Sorbadere, F.; Rosenthal, A.; Frost, D. J.; McCammon, C. A.

    2014-12-01

    The presence of ferric iron (Fe3+) in the mantle plays a significant role in the oxygen fugacity (fO2) of the Earth's interior. This has a wide range of implications for Earth related processes ranging from the composition of the atmosphere to magmatic phase relations during melting and crystallization processes [1]. A major source of Earth's mantle magmas is spinel peridotite. Despite its low abundance, spinel (Fe3+/?Fe = 15-34%, [2]) is the main contributor of Fe3+to the melt upon partial melting. Analyses of Fe3+ on small areas of spinel and melt are required to study the Fe3+ behavior during partial melting of spinel peridotite. Fe K-edge X-ray Absorption Near Edge Structure (XANES) combines both high precision and small beam size, but requires standards with a wide range of Fe3+ content to obtain good calibration. Glasses with varying Fe3+ content are easily synthesized [3, 4]. Spinel, however, presents a challenge for experimental standards due to the low diffusion of Cr and Al preventing compositional homogeneity. Natural spinel standards are often used, but only cover a narrow Fe3+ range. Thus, there is a need for better experimental spinel standards over a wider range of fO2. Our study involves making experimental mantle spinels with variable Fe3+ content. We used a sol-gel auto-combustion method to synthesize our starting material [5]. FMQ-2, FMQ+0, and air fO2 conditions were established using a gas mixing furnace. Piston cylinder experiments were performed at 1.5GPa, and 1310 -1370C to obtain solid material for XANES. To maintain distinct oxidizing conditions, three capsules were used: graphite for reduced, Re for intermediate and AuPd for oxidized conditions. The spinels were analyzed by Mssbauer spectroscopy. Fe3+/?Fe ranged from 0.3 to 0.6. These values are consistent with the Fe edge position obtained using XANES analyses, between 7130 and 7132 eV, respectively. Our spinels are thus suitable standards for Fe3+ measurements in peridotite systems and can be used to determine Fe3+/?Fe ratio of spinel during magma genesis from a peridotite source. [1] Canil et al. (1994), EPSL 123, 205-220. [2] Frost & McCammon (2008), Annu Rev Earth Planet Sci 36, 389-420. [3] Cottrell & Kelley (2011), EPSL 305, 270-282. [4] Falloon et al. (2008) J. Petrol. 49, 591-613. [5] Vader et al. (2013), J mater Sci 25, 765-771.

  8. Nitrosative Stress and Apoptosis by Intravenous Ferumoxytol, Iron Isomaltoside 1000, Iron Dextran, Iron Sucrose, and Ferric Carboxymaltose in a Nonclinical Model.

    PubMed

    Toblli, J E; Cao, G; Giani, J F; Dominici, F P; Angerosa, M

    2015-07-01

    Iron is involved in the formation as well as in the scavenging of reactive oxygen and nitrogen species. Thus, iron can induce as well as inhibit both oxidative and nitrosative stress. It also has a key role in reactive oxygen and nitrogen species-mediated apoptosis. We assessed the differences in tyrosine nitration and caspase 3 expression in the liver, heart, and kidneys of rats treated weekly with intravenous ferumoxytol, iron isomaltoside 1000, iron dextran, iron sucrose and ferric carboxymaltose (40?mg iron/kg body weight) for 5 weeks. Nitrotyrosine was quantified in tissue homogenates by Western blotting and the distribution of nitrotyrosine and caspase 3 was assessed in tissue sections by immunohistochemistry. Ferric carboxymaltose and iron sucrose administration did not result in detectable levels of nitrotyrosine or significant levels of caspase 3?vs. control in any of the tissue studied. Nitrotyrosine and caspase 3 levels were significantly (p<0.01) increased in all assessed organs of animals treated with iron dextran and iron isomaltoside 1000, as well as in the liver and kidneys of ferumoxytol-treated animals compared to isotonic saline solution (control). Nitrotyrosine and caspase 3 levels were shown to correlate positively with the amount of Prussian blue-detectable iron(III) deposits in iron dextran- and iron isomaltoside 1000-treated rats but not in ferumoxytol-treated rats, suggesting that iron dextran, iron isomaltoside 1000 and ferumoxytol induce nitrosative (and oxidative) stress as well as apoptosis via different mechanism(s). PMID:25050519

  9. Effects of phosphate and silicate on the transformation of hydroxycarbonate green rust to ferric oxyhydroxides

    NASA Astrophysics Data System (ADS)

    Feng, Xionghan; Wang, Xiaoming; Zhu, Mengqiang; Koopal, Luuk K.; Xu, Huanhuan; Wang, Yan; Liu, Fan

    2015-12-01

    Hydroxycarbonate green rust (GR1(CO32-)) was prepared by oxidation of aerated aqueous suspensions of Fe(II) hydroxide, and the presence of light promoted the transformation of GR1(CO32-) by dissolved O2 at pH 7.8 and 25 C. Further transformation of GR1(CO32-) in the light was conducted in the presence of orthophosphate (P) or silicate (Si) anions, followed by solution analysis and solid product characterization using X-ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FTIR). Results show that both P and Si anions significantly affect the transformation of GR1(CO32-) through adsorption on the intermediate products. The time required for complete GR1(CO32-) transformation and the phases, crystallinity and morphology of the transformation products all depend on the Fe/anion molar ratio. When compared to the control, the transformation can be promoted by low Si concentrations but retarded by P. With decreasing Fe/P ratio, the products change from acicular goethite (absence of P) to tabular lepidocrocite (Fe/P: 120-48) and to mixed phases of platelets of ferric GR1(CO32-) (EX-GR1) and minor ferrihydrite (Fe/P: 24-3). In terms of Si, the products are goethites when the Fe/Si ratio of 48-12, and with increasing ratio, the goethite crystallinity and particle size decrease and the morphology changes from acicular (absence of Si) to plate-like or isodimensional particles. The goethite morphology at low Fe/Si ratios is comparable to natural goethite samples commonly found in soils. At Fe/Si = 3, the products are EX-GR1 platelets with minor ferrihydrite coexisting. The likely pathway of the oxidative GR1(CO32-) transformation in the control system and in the presence of low concentrations of Si (Fe/Si ? 12) is GR1(CO32-) ? amorphous ?-FeOOH-like phase ? ?-FeOOH via a dissolution-oxidation-precipitation mechanism. In addition, Fe(II) released during dissolution of GR1(CO32-) is adsorbed on the products and the transformation of the ?-FeOOH-like phase to goethite is catalyzed by the adsorbed Fe(II). For the P system, the released Fe(II) forms ternary surface complexes with P on the mineral surfaces without any catalytic role, leading to the formation of lepidocrocite at low P concentrations. Clearly, the oxidative transformation of green rust to various crystalline iron oxyhydroxides depends on the type and concentration (Fe/anion molar ratio) of co-existing anions. This study also suggests that the natural goethite formed by Fe(II) oxidation in the form of plate-like or isodimensional particles is most likely related to the ubiquitous presence of silicates in soil environments.

  10. Suboxic Deposition of Ferric Iron by Bacteria in Opposing Gradients of Fe(II) and Oxygen at Circumneutral pH

    PubMed Central

    Sobolev, Dmitri; Roden, Eric E.

    2001-01-01

    The influence of lithotrophic Fe(II)-oxidizing bacteria on patterns of ferric oxide deposition in opposing gradients of Fe(II) and O2 was examined at submillimeter resolution by use of an O2 microelectrode and diffusion microprobes for iron. In cultures inoculated with lithotrophic Fe(II)-oxidizing bacteria, the majority of Fe(III) deposition occurred below the depth of O2 penetration. In contrast, Fe(III) deposition in abiotic control cultures occurred entirely within the aerobic zone. The diffusion microprobes revealed the formation of soluble or colloidal Fe(III) compounds during biological Fe(II) oxidation. The presence of mobile Fe(III) in diffusion probes from live cultures was verified by washing the probes in anoxic water, which removed ca. 70% of the Fe(III) content of probes from live cultures but did not alter the Fe(III) content of probes from abiotic controls. Measurements of the amount of Fe(III) oxide deposited in the medium versus the probes indicated that ca. 90% of the Fe(III) deposited in live cultures was formed biologically. Our findings show that bacterial Fe(II) oxidation is likely to generate reactive Fe(III) compounds that can be immediately available for use as electron acceptors for anaerobic respiration and that biological Fe(II) oxidation may thereby promote rapid microscale Fe redox cycling at aerobic-anaerobic interfaces. PMID:11229928

  11. Turnover of glucose and acetate coupled to reduction of nitrate, ferric iron and sulfate and to methanogenesis in anoxic rice field soil.

    PubMed

    Chidthaisong; Conrad

    2000-01-01

    Turnover of glucose and acetate in the presence of active reduction of nitrate, ferric iron and sulfate was investigated in anoxic rice field soil by using [U-(14)C]glucose and [2-(14)C]acetate. The turnover of glucose was not much affected by addition of ferrihydrite or sulfate, but was partially inhibited (60%) by addition of nitrate. Nitrate addition also strongly reduced acetate production from glucose while ferrihydrite and sulfate addition did not. These results demonstrate that ferric iron and sulfate reducers did not outcompete fermenting bacteria for glucose at endogenous concentrations. Nitrate reducers may have done so, but glucose fermentation may also have been inhibited by accumulation of toxic denitrification intermediates (nitrite, NO, N(2)O). Addition of nitrate resulted in complete inhibition of CH(4) production from [U-(14)C]glucose and [2-(14)C]acetate. However, addition of ferrihydrite or sulfate decreased the production of (14)CH(4) from [U-(14)C]glucose by only 70 and 65%, respectively. None of the electron acceptors significantly increased the production of (14)CO(2) from [U-(14)C]glucose, but all increased the production of (14)CO(2) from [2-(14)C]acetate. Uptake of acetate was faster in the presence of either nitrate, ferrihydrite or sulfate than in the unamended control. Addition of ferrihydrite and sulfate reduced (14)CH(4) production from [2-(14)C]acetate by 83 and 92%, respectively. Chloroform completely inhibited the methanogenic consumption of acetate. It also inhibited the oxidation of acetate, completely in the presence of sulfate, but not in the presence of nitrate or ferrihydrite. Our results show that, besides the possible toxic effect of products of nitrate reduction (NO, NO(2)(-) and N(2)O) on methanogens, nitrate reducers, ferric iron reducers and sulfate reducers were active enough to outcompete methanogens for acetate and channeling the flow of electrons away from CH(4) towards CO(2) production. PMID:10620721

  12. Study of arsenic(III) and arsenic(V) removal from waters using ferric hydroxide supported on silica gel prepared at low pH.

    PubMed

    Cifti, Tlin Deniz; Yayayrk, Onur; Henden, Emr

    2011-01-01

    Removal of As(III) and As(V) species using ferric hydroxide supported on silica gel was studied. Laboratory reagent quality silica gel was used as to avoid uncertainties that may be caused by impurities. Ferric hydroxide precipitation was realized at various pH values and a relatively low pH 6.0 was chosen because, at this pH, the highest arsenic removal capacity and removal efficiency were obtained and clear supernatant solution was observed. It was also shown by arsenic speciation analysis at trace level that As(III) is adsorbed onto ferric hydroxide partly without oxidation to As(V); this has been a controversial point in the literature. The effects on arsenic removal of some parameters such as pH, flow rate and matrix ions were investigated. In the batch method, initial pH change of the solution did not significantly affect the arsenic removal efficiencies for As(III) and As(V) in the pH range of 3.1-9.7. This was attributed to the decreases of the initial pH values to around 5 at equilibrium. The column capacities of 1.32 mg As(III)/g sorbent and 1.21 mg As(V)/g sorbent were found for initial concentration of 1.00 mg/L arsenic. Batch capacities were 16.2 mg As(III)/g sorbent and 17.7 mg As(V)/g sorbent for initial arsenic concentration of 100 mg/L. The method was applied successfully to the removal of As(III) and As(V) from drinking water, geothermal water and mineral water. PMID:21780702

  13. Efficacy and Safety of Ferric Chloride in Controlling Hepatic Bleeding; An Animal Model Study

    PubMed Central

    Nouri, Saeed; Sharif, Mohammad Reza

    2014-01-01

    Background: Controlling parenchymal hemorrhage especially in liver parenchyma, despite all the progress in surgical science, is still one of the challenges surgeons face saving patients lives and there is a research challenge among researchers in this field to introduce a more effective method. Objectives: This study attempts to determine the haemostatic effect of ferric chloride and compare it with that of the standard method (suturing technique) in controlling bleeding from liver parenchymal tissue. Materials and Methods: In this animal model study 60 male Wistar rats were used. An incision, two centimeters (cm) long and half a cm deep, was made on each rats liver and the hemostasis time was measured once using ferric chloride with different concentrations (5%, 10%, 15%, 25% and 50%) and then using the control method (i.e. controlling bleeding by suturing). The liver tissue was examined for pathological changes. Results: The hemostasis time of ferric chloride concentration groups was significantly less than that of the control group (P value < 0.001). The pathologic examination showed the highest frequency of low grade inflammation based on the defined pathological grading. Conclusions: Ferric chloride is an effective haemostatic agent in controlling liver parenchymal tissue hemorrhage in an animal model. PMID:24976842

  14. Role of lipid peroxidation in ferric lactate-enhanced calcium uptake by Ehrlich carcinoma cells.

    PubMed

    Anghileri, L J

    1993-04-15

    Comparison of Ca2+ uptake by Ehrlich carcinoma cells in presence of ferric lactate or aluminum lactate, and formation of thiobarbituric acid-reactive substances, suggests that lipid peroxidation is associated with but not the cause of calcium overload that can lead to cell injury and death. PMID:8477836

  15. A novel electrochemical process for the recovery and recycling of ferric chloride from precipitation sludge.

    PubMed

    Mejia Likosova, E; Keller, J; Poussade, Y; Freguia, S

    2014-03-15

    During wastewater treatment and drinking water production, significant amounts of ferric sludge (comprising ferric oxy-hydroxides and FePO4) are generated that require disposal. This practice has a major impact on the overall treatment cost as a result of both chemical addition and the disposal of the generated chemical sludge. Iron sulfide (FeS) precipitation via sulfide addition to ferric phosphate (FePO4) sludge has been proven as an effective process for phosphate recovery. In turn, iron and sulfide could potentially be recovered from the FeS sludge, and recycled back to the process. In this work, a novel process was investigated at lab scale for the recovery of soluble iron and sulfide from FeS sludge. Soluble iron is regenerated electrochemically at a graphite anode, while sulfide is recovered at the cathode of the same electrochemical cell. Up to 6018% soluble Fe and 4611% sulfide were recovered on graphite granules for up-stream reuse. Peak current densities of 9.54.2Am(-2) and minimum power requirements of 2.40.5kWhkgFe(-1) were reached with real full strength FeS suspensions. Multiple consecutive runs of the electrochemical process were performed, leading to the successful demonstration of an integrated process, comprising FeS formation/separation and ferric/sulfide electrochemical regeneration. PMID:24397913

  16. The rate of decomposition of the ferric-thiosulfate complex in acidic aqueous solutions

    SciTech Connect

    Williamson, M.A.; Rimstidt, J.D. )

    1993-08-01

    The rate of decomposition of the ferric thiosulfate complex varies as the square of the concentration of the complex. The rate of decomposition of the complex was determined by following the change in absorbance due to the complex as a function of time. Regression of log rate vs. log m[sub FeS[sub 2]O[sub 3][sup +

  17. 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...

  18. 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...

  19. 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...

  20. TRANSFORMATION AND MOBILIZATION OF ARSENIC ADSORBED ON GRANULAR FERRIC HYDROXIDE UNDER BIO-REDUCTIVE CONDITIONS

    EPA Science Inventory

    Biotic and abiotic reduction of arsenic (V) and iron (III) influences the partioning of arsenic (As) between the solid and aqueous phases in soils, sediments and wastes. In this study, laboratory experiments on arsenic adsorbed on granular ferric hydroxide (GFH) was performed to ...

  1. 40 CFR 180.1302 - Sodium Ferric Ethylenediaminetetraacetate (EDTA); exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Ethylenediaminetetraacetate (EDTA); exemption from the requirement of a tolerance. 180.1302 Section 180.1302 Protection of... Ethylenediaminetetraacetate (EDTA); exemption from the requirement of a tolerance. An exemption from the requirement of a tolerance is established for residues of sodium ferric EDTA in or on all food commodities when applied as...

  2. 40 CFR 180.1302 - Sodium Ferric Ethylenediaminetetraacetate (EDTA); exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Ethylenediaminetetraacetate (EDTA); exemption from the requirement of a tolerance. 180.1302 Section 180.1302 Protection of... Ethylenediaminetetraacetate (EDTA); exemption from the requirement of a tolerance. An exemption from the requirement of a tolerance is established for residues of sodium ferric EDTA in or on all food commodities when applied as...

  3. 40 CFR 180.1302 - Sodium Ferric Ethylenediaminetetraacetate (EDTA); exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Ethylenediaminetetraacetate (EDTA); exemption from the requirement of a tolerance. 180.1302 Section 180.1302 Protection of... Ethylenediaminetetraacetate (EDTA); exemption from the requirement of a tolerance. An exemption from the requirement of a tolerance is established for residues of sodium ferric EDTA in or on all food commodities when applied as...

  4. 40 CFR 180.1302 - Sodium Ferric Ethylenediaminetetraacetate (EDTA); exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Ethylenediaminetetraacetate (EDTA); exemption from the requirement of a tolerance. 180.1302 Section 180.1302 Protection of... Ethylenediaminetetraacetate (EDTA); exemption from the requirement of a tolerance. An exemption from the requirement of a tolerance is established for residues of sodium ferric EDTA in or on all food commodities when applied as...

  5. MOLECULAR AND PHENOTYPIC CHARACTERIZATION OF TRANSGENIC SOYBEAN EXPRESSING THE ARABIDOPSIS FERRIC CHELATE REDUCTASE GENE, FRO2

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soybean (Glycine max Merr.) production is reduced under iron-limiting calcareous soils throughout the upper Midwest regions of the U.S. Soybean like other dicotyledonous plants responds to iron-limiting environments by induction of an active proton pump, a ferric iron reductase and a Fe transporter....

  6. Involvement of Superoxide Radical in Extracellular Ferric Reduction by Iron-Deficient Bean Roots 1

    PubMed Central

    Cakmak, Ismail; van de Wetering, Dirk A. M.; Marschner, Horst; Bienfait, H. Frits

    1987-01-01

    The recent proposal of Tipton and Thowsen (Plant Physiol 79: 432-435) that iron-deficient plants reduce ferric chelates in cell walls by a system dependent on the leakage of malate from root cells was tested. Results are presented showing that this mechanism could not be responsible for the high rates of ferric reduction shown by roots of iron-deficient bean (Phaseolus vulgaris L. var Prlude) plants. The role of O2 in the reduction of ferric chelates by roots of iron-deficient bean plants was also tested. The rate of Fe(III) reduction was the same in the presence and in the absence of O2. However, in the presence of O2 the reaction was partially inhibited by superoxide dismutase (SOD), which indicates a role for the superoxide radical, O2[unk], as a facultative intermediate electron carrier. The inhibition by SOD increased with substrate pH and with decrease in concentration of the ferrous scavenger bathophenanthroline-disulfonate. The results are consistent with a mechanism for transmembrane electron transport in which a flavin or quinone is the final electron carrier in the plasma membrane. The results are discussed in relation to the ecological importance that O2[unk] may have in the acquisition of ferric iron by dicotyledonous plants. PMID:16665677

  7. Microdetermination of proteins by resonance light scattering technique based on aggregation of ferric nanoparticles

    NASA Astrophysics Data System (ADS)

    Shu-hong, Zhang; Yong-shan, Fan; Shuo, Feng; Yun-feng, Zhang

    2009-05-01

    A new method for protein determination is presented that allows measurement of proteins at nanogram levels with simple procedure. The method applies a resonance light scattering (RLS) technique, but based on aggregation of ferric nanoparticles on protein template instead of the usual interaction of organic days with proteins. By mixing ferric colloid with sodium cacodylate buffer solution, ferric nanoparticles can be obtained in the size of about 5 nm and kept their positive charges in a wide range of pH 1.8-7.6. The ferric nanoparticles can interact with proteins to form particular aggregates and thus result in strong and stable RLS. Under optimal conditions (wavelength of 451 nm and pH 7.4), few substances interfere with this assay. The detection limitation of bovine serum albumin (BSA) is 6.6 ng/mL and the linear range is 20-700 ng/mL. This method gives almost identical responses for BSA, human serum albumin (HSA) and γ-globulin (γ-G), and can be used for the determination of total proteins in human serum with satisfactory results.

  8. Use of ferric thiocyanate derivatization for quantification of polysorbate 80 in high concentration protein formulations.

    PubMed

    Savjani, Nimesh; Babcock, Eugene; Khor, Hui Koon; Raghani, Anil

    2014-12-01

    Quantitation of polysorbate 80 in high protein formulation using solid-phase extraction (SPE) followed by derivatization with cobalt thiocyanate and UV measurement of the complex at 620 nm resulted in lower recovery of polysorbate 80. Dilution of protein samples with water improved the recovery of polysorbate, however, it compromised the sensitivity of the method when cobalt thiocyanate was used for derivatization. The presented work discusses an evaluation of alternative approaches for increasing the sensitivity of the quantitation method for polysorbate using ferric thiocyanate and molybdenum thiocyanate. Ferric thiocyanate complex of polysorbate 80 exhibited the highest sensitivity among the metals thiocyanate evaluated in the current work. The improvement in the sensitivity through derivatization with ferric thiocyanate allowed 10-fold dilution of a 140 mg mL(-1) protein sample without affecting the recovery or compromising the sensitivity of polysorbate 80 quantitation, indicating that this methodology could be used as an alternate approach for the quantitation of polysorbate 80 in high concentration protein formulations. Stability of ferric thiocynate and cobalt thiocyanate complex was also studied. When these complexes were allowed to equilibrate for 1h between an organic layer containing polysorbate/thiocynate complex and an aqueous layer containing un-reacted metal thiocyanate, it resulted in the most reproducible UV absorbance measurements. The SPE method for quantification of polysorbate 80 using ferric thiocyanate for derivatization provided accuracy (% spike recovery) within 107%, reproducibility (%relative standard deviation) less than 11.7%. The method is linear from 0.0001 to 0.008% polysorbate 80 concentrations in the formulations with protein formulations as high as 140 mg mL(-1). PMID:25159444

  9. Experimental study on a nonlinear photonics process of Er(0.5)Yb(3):FOV oxyfluoride nanophase vitroceramics.

    PubMed

    Chen, Xiaobo; Song, Zengfu; Hu, Lili; Zhang, Junjie; Wen, Lei

    2007-07-15

    We study the nonlinear photonics of rare-earth-doped oxyfluoride nanophase vitroceramics (FOV), oxyfluoride glass (FOG), and ZBLAN fluoride glass. We found that an interesting fluorescence intensity inversion phenomenon between red and green fluorescence occurs from Er(0.5)Yb(3):FOV. The dynamic range summation operator of the intensity inversion between red and green fluorescence of Er(0.5)Yb(3):FOV is about 5.753 x 10(2), which is 100 to 1000 times larger than those of other materials. One of the applications of this phenomenon is double-wavelength fluorescence falsification-preventing technology, which is proved to possess the novel antifriction loss and antiscribble properties. PMID:17632629

  10. Distinguishing Multiple Surface Species of Glutamate on Hydrous Ferric Oxide (HFO)

    NASA Astrophysics Data System (ADS)

    Cleaves, H., II; Sverjensky, D. A.; Jonsson, C. M.; Jonsson, C. L.; Hazen, R. M.

    2008-12-01

    Surface complexation models provide a way of integrating the results of attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopic studies with bulk adsorption measurements. Assuming that glutamate adsorbs similarly on HFO and amorphous titanium dioxide (ATD), we used ATR-FTIR results for glutamate on ATD [1] to construct a surface complexation model for glutamate on HFO [2]. Three surface complexes were distinguished following the ATR-FTIR study: a bridging-bidentate, a chelating-monodentate and a chelating species,corresponding to 4, 3 and 2 points of attachment of the glutamate to surface functional groups, respectively. In this regard, the ATR-FTIR spectroscopic results and the model surface complexes agree. However, the model surface complexes contain partly inner-sphere binding and partly H- bonding or outer-sphere binding. For example, the model bridging-bidentate species has one oxygen of each carboxylate functional group bound in an inner-sphere mode, whereas the other oxygen of each carboxylate functional group is bound with a H-bond or as an outer-sphere species to a surface >FeOH group. The selection of this species gave the best reaction stoichiometry for the model of the adsorption data. However, it was suggested in [1] that all four glutamate oxygens may bind in an inner-sphere mode to surface cations. Distinguishing between these possibilities should be a primary goal of combined spectroscopic and theoretical molecular calculations. [1] Roddick-Lanzilotta A.D. and McQuillan A.J. (2000) J. Colloid & Interface Sci. 227, 48-54. [2] Sverjensky, D. A. et al. (2008) Env. Sci. & Technology, 42, 6034-6039.

  11. Natural media with negative index of refraction: Perspectives of complex transition metal oxides (Review Article)

    NASA Astrophysics Data System (ADS)

    Fertman, E. L.; Beznosov, A. B.

    2011-07-01

    The capabilities of perovskite-like compounds with the effect of colossal magnetoresistance (CMR) and some other complex oxides to have a negative index of refraction (NIR) are considered. Physical properties of these compounds are also analyzed from the standpoint of designing tunable metamaterials on their base. Of particular interest are temperature and magnetic field driven first-order transformations in oxides with perovskite structure and in spinels. These transformations give rise to nanophase separated states, using which the properties of negative refraction can be affected. The magnetic-field controlled metamaterials with CMR oxides as a boundary NIR media for a photonic crystal are discussed.

  12. Chemical evolution. XL - Clay-mediated oxidation of diaminomaleonitrile

    NASA Technical Reports Server (NTRS)

    Ferris, J. P.; Hagan, W. J., Jr.; Alwis, K. W.; Mccrea, J.

    1982-01-01

    The inhibition of the oligomerization of HCN by montmorillonite clays is shown to be caused by oxidation of diaminomaleonitrile (DAMN) by ferric ion in the clay lattice, with ferrous ion and oxalic acid the reaction products. It is demonstrated that diiminosuccinonitrile is the initial reaction product and is rapidly hydrolized to oxalic acid and HCN. The same oxidative transformations are effected by ferric ion bound to Dowex 50, ferric ion in solution, and Ni(NH3)6(2+). The rate of reaction of DAMN indicates no catalytic role for the clay in the oxidation of DAMN, and little reaction of the latter was observed with montmorillonite in which the bulk of the iron was in the divalent state. The possible significance of these redox reactions to chemical evolution is discussed.

  13. Mineralogy at Gusev Crater from the Mossbauer spectrometer on the Spirit Rover

    NASA Technical Reports Server (NTRS)

    Morris, R. V.; Klingelhofer, G.; Bernhardt, B.; Schroder, C.; Rodionov, D. S.; De Souza, P. A. Jr; Yen, A.; Gellert, R.; Evlanov, E. N.; Foh, J.; Kankeleit, E.; Gutlich, P.; Ming, D. W.; Renz, F.; Wdowiak, T.; Squyres, S. W.; Arvidson, R. E.

    2004-01-01

    Mossbauer spectra measured on Mars by the Spirit rover during the primary mission are characterized by two ferrous iron doublets (olivine and probably pyroxene) and a ferric iron doublet (tentatively associated to nanophase ferric iron oxide). Two sextets resulting from nonstoichiometric magnetite are also present, except for a coating on the rock Mazatzal, where a hematite-like sextet is present. Greater proportions of ferric-bearing phases are associated with undisturbed soils and rock surfaces as compared to fresh rock surfaces exposed by grinding. The ubiquitous presence of olivine in soil suggests that physical rather than chemical weathering processes currently dominate at Gusev crater.

  14. Mineralogy at Gusev Crater from the Mössbauer spectrometer on the Spirit Rover.

    PubMed

    Morris, R V; Klingelhöfer, G; Bernhardt, B; Schröder, C; Rodionov, D S; De Souza, P A; Yen, A; Gellert, R; Evlanov, E N; Foh, J; Kankeleit, E; Gütlich, P; Ming, D W; Renz, F; Wdowiak, T; Squyres, S W; Arvidson, R E

    2004-08-01

    Mössbauer spectra measured on Mars by the Spirit rover during the primary mission are characterized by two ferrous iron doublets (olivine and probably pyroxene) and a ferric iron doublet (tentatively associated to nanophase ferric iron oxide). Two sextets resulting from nonstoichiometric magnetite are also present, except for a coating on the rock Mazatzal, where a hematite-like sextet is present. Greater proportions of ferric-bearing phases are associated with undisturbed soils and rock surfaces as compared to fresh rock surfaces exposed by grinding. The ubiquitous presence of olivine in soil suggests that physical rather than chemical weathering processes currently dominate at Gusev crater. PMID:15297666

  15. Investigations of ferric heme cyanide photodissociation in myoglobin and horseradish peroxidase.

    PubMed

    Zeng, Weiqiao; Sun, Yuhan; Benabbas, Abdelkrim; Champion, Paul M

    2013-04-18

    The photodissociation of cyanide from ferric myoglobin (MbCN) and horseradish peroxidase (HRPCN) has definitively been observed. This has implications for the interpretation of ultrafast IR (Helbing et al. Biophys. J. 2004, 87, 1881-1891) and optical (Gruia et al. Biophys. J. 2008, 94, 2252-2268) studies that had previously suggested the Fe-CN bond was photostable in MbCN. The photolysis of ferric MbCN takes place with a quantum yield of ~75%, and the resonance Raman spectrum of the photoproduct observed in steady-state experiments as a function of laser power and sample spinning rate is identical to that of ferric Mb (metMb). The data are quantitatively analyzed using a simple model where cyanide is photodissociated and, although geminate rebinding with a rate of kBA ? (3.6 ps)(-1) is the dominant process, some CN(-) exits from the distal heme pocket and is replaced by water. Using independently determined values for the CN(-) association rate, we find that the CN(-) escape rate from the ferric myoglobin pocket to the solution at 293 K is kout ? (1-2) 10(7) s(-1). This value is very similar to, but slightly larger than, the histidine gated escape rate of CO from Mb (1.1 10(7) s(-1)) under the same conditions. The analysis leads to an escape probability kout/(kout + kBA) ~ 10(-4), which is unobservable in most time domain kinetic measurements. However, the photolysis is surprisingly easy to detect in Mb using cw resonance Raman measurements. This is due to the anomalously slow CN(-) bimolecular association rate (170 M(-1) s(-1)), which arises from the need for water to exchange at the ferric heme binding site of Mb. In contrast, ferric HRP does not have a heme bound water molecule and its CN(-) bimolecular association rate is larger by ~10(3), making the CN(-) photolysis more difficult to observe. PMID:23472676

  16. The oxidizing power of illinois coal. I. The reaction with titanous chloride

    USGS Publications Warehouse

    Yoke, G.R.; Harman, C. Alex

    1941-01-01

    Illinois coals which have been exposed to air or oxygen show a small but definite ability to oxidize titanous chloride. This oxidizing power is gained very rapidly when freshly ground coal is exposed to air. Neither the magnitude nor the rapid increase of this oxidizing power can be accounted for entirely by the presence or the formation of soluble ferric compounds in the coal.

  17. Primary Ferric Iron-Bearing Rhnite in Plutonic Igneous Angrite NWA 4590: Implications for Redox Conditions on the Angrite Parent Body

    NASA Astrophysics Data System (ADS)

    Kuehner, S. M.; Irving, A. J.

    2007-12-01

    Northwest Africa 4590 is a heterogeneous olivine gabbro with cumulate texture composed of Al-Ti-rich clinopyroxene, pure anorthite, Ca-rich olivine, kirschsteinite and ulvspinel, with accessory troilite, merrillite, Ca silicophosphate, kamacite and glasses [1]. Rhnite now has been identified in this specimen (for the first time in any angrite) as (1) a large (0.65 mm long), blocky, anhedral grain adjacent to anorthite, kirschsteinite and troilite, (2) ca. 15 micron grains along grain boundaries of the major phases (in one case in contact with clinopyroxene and metal), and (3) ca. 30 micron grains within melt inclusions and veins composed of kirschsteinite, olivine, anorthite, troilite, hercynite and glass. The rhnite is nearly opaque in transmitted light, with a deep cinnamon-red color on thin grain edges. The average composition of the largest grain is (in wt.%): SiO2 23.6, TiO2 9.9, Al2O3 16.3, Cr2O3 0.1, FeOt 33.6, MnO 0.14, MgO 3.5, CaO 13.1. Stoichiometry (14 cations, 20 oxygen atoms) requires about 12% of the total iron to be in the ferric state, resulting in the nominal formula: (Ca2.01Mn0.02)(Fe2+3.55Fe3+0.45Mg0.75Al0.12Cr0.15)Ti0.9 5(Si3.37Al2.63)O20 In the co-existing ulvspinel about 18% of the iron must be ferric to achieve charge balance; likewise, Fe-Ti spinel coexisting with metal in Angra dos Reis contains ferric iron [2]. In contrast, the spinel (Cr-pleonaste) in metal-rich angrite NWA 2999 is stoichiometric without any apparent ferric iron. The coexistence of ferric iron- bearing silicate and oxide phases with Fe metal implies that the oxygen fugacity during crystallization of NWA 4590 was somewhat more oxidizing than that of the IW buffer. Compositions of primary (pre-exsolution) olivine and kirschsteinite in NWA 4590 record a minimum magmatic temperature of 910-950C, based on the solvus of [3]. Previous experimental studies [4] also imply that other metal-bearing plutonic (AdoR, LEW 86010) and quench-textured (LEW 87051) angrites equilibrated at oxygen fugacities near QFM - 2 log units and relatively high temperatures. Although not previously known from angrites, rhnite has been reported from terrestrial alkalic rocks, CV chondrites and a lunar mare basalt [5]. [1] Irving A. et al. (2006) EOS, Trans. AGU 87, #P51E-1245; Kuehner S. and Irving A. (2007) LPS XXXVIII, #1344 [2] Prinz M. et al. (1977) EPSL 35, 317-330 [3] Mukhopadhyay D. and Lindsley D. (1983) Amer. Mineral. 68, 1089-1094 [4] Jurewicz A. et al. (1991) Science 252, 695-698; McKay G. et al. (1994) GCA 58, 2911-2919 [5] Treiman A. (2007) LPS XXXVIII, #1244.

  18. Energy cascades, excited state dynamics, and photochemistry in cob(III)alamins and ferric porphyrins.

    PubMed

    Rury, Aaron S; Wiley, Theodore E; Sension, Roseanne J

    2015-03-17

    Porphyrins and the related chlorins and corrins contain a cyclic tetrapyrrole with the ability to coordinate an active metal center and to perform a variety of functions exploiting the oxidation state, reactivity, and axial ligation of the metal center. These compounds are used in optically activated applications ranging from light harvesting and energy conversion to medical therapeutics and photodynamic therapy to molecular electronics, spintronics, optoelectronic thin films, and optomagnetics. Cobalt containing corrin rings extend the range of applications through photolytic cleavage of a unique axial carbon-cobalt bond, permitting spatiotemporal control of drug delivery. The photochemistry and photophysics of cyclic tetrapyrroles are controlled by electronic relaxation dynamics including internal conversion and intersystem crossing. Typically the electronic excitation cascades through ring centered ππ* states, ligand to metal charge transfer (LMCT) states, metal to ligand charge transfer (MLCT) states, and metal centered states. Ultrafast transient absorption spectroscopy provides a powerful tool for the investigation of the electronic state dynamics in metal containing tetrapyrroles. The UV-visible spectrum is sensitive to the oxidation state, electronic configuration, spin state, and axial ligation of the central metal atom. Ultrashort broadband white light probes spanning the range from 270 to 800 nm, combined with tunable excitation pulses, permit the detailed unravelling of the time scales involved in the electronic energy cascade. State-of-the-art theoretical calculations provide additional insight required for precise assignment of the states. In this Account, we focus on recent ultrafast transient absorption studies of ferric porphyrins and corrin containing cob(III)alamins elucidating the electronic states responsible for ultrafast energy cascades, excited state dynamics, and the resulting photoreactivity or photostability of these compounds. Iron tetraphenyl porphyrin chloride (Fe((III))TPPCl) exhibits picosecond decay to a metal centered d → d* (4)T state. This state decays on a ca. 16 ps time scale in room temperature solution but persists for much longer in a cryogenic glass. The photoreactivity of the (4)T state may lead to novel future applications for these compounds. In contrast, the nonplanar cob(III)alamins contain two axial ligands to the central cobalt atom. The upper axial ligand can be an alkyl group as in the two biologically active coenzymes or a nonalkyl ligand such as -CN in cyanocobalamin (vitamin B12) or -OH in hydroxocobalamin. The electronic structure, energy cascade, and bond cleavage of these compounds is sensitive to the details of the axial ligand. Nonalkylcobalamins exhibit ultrafast internal conversion to a low-lying state of metal to ligand or ligand to metal charge transfer character. The compounds are generally photostable with ground state recovery complete on a time scale of 2-7 ps in room temperature aqueous solution. Alkylcobalamins exhibit ultrafast internal conversion to an S1 state of d/π → π* character. Most compounds undergo bond cleavage from this state with near unit quantum yield within ∼100 ps. Recent theoretical calculations provide a potential energy surface accounting for these observations. Conformation dependent mixing of the corrin π and cobalt d orbitals plays a significant role in the observed photochemistry and photophysics. PMID:25741574

  19. Functional Analysis of the Ferric Uptake Regulator Gene fur in Xanthomonas vesicatoria

    PubMed Central

    Liu, Huiqin; Dong, Chunling; Zhao, Tingchang; Han, Jucai; Wang, Tieling; Wen, Xiangzhen; Huang, Qi

    2016-01-01

    Iron is essential for the growth and survival of many organisms. Intracellular iron homeostasis must be maintained for cell survival and protection against iron toxicity. The ferric uptake regulator protein (Fur) regulates the high-affinity ferric uptake system in many bacteria. To investigate the function of the fur gene in Xanthomonas vesicatoria (Xv), we generated a fur mutant strain, fur-m, by site-directed mutagenesis. Whereas siderophore production increased in the Xv fur mutant, extracellular polysaccharide production, biofilm formation, swimming ability and quorum sensing signals were all significantly decreased. The fur mutant also had significantly reduced virulence in tomato leaves. The above-mentioned phenotypes significantly recovered when the Xv fur mutation allele was complemented with a wild-type fur gene. Thus, Fur either negatively or positively regulates multiple important physiological functions in Xv. PMID:26910324

  20. Functional Analysis of the Ferric Uptake Regulator Gene fur in Xanthomonas vesicatoria.

    PubMed

    Liu, Huiqin; Dong, Chunling; Zhao, Tingchang; Han, Jucai; Wang, Tieling; Wen, Xiangzhen; Huang, Qi

    2016-01-01

    Iron is essential for the growth and survival of many organisms. Intracellular iron homeostasis must be maintained for cell survival and protection against iron toxicity. The ferric uptake regulator protein (Fur) regulates the high-affinity ferric uptake system in many bacteria. To investigate the function of the fur gene in Xanthomonas vesicatoria (Xv), we generated a fur mutant strain, fur-m, by site-directed mutagenesis. Whereas siderophore production increased in the Xv fur mutant, extracellular polysaccharide production, biofilm formation, swimming ability and quorum sensing signals were all significantly decreased. The fur mutant also had significantly reduced virulence in tomato leaves. The above-mentioned phenotypes significantly recovered when the Xv fur mutation allele was complemented with a wild-type fur gene. Thus, Fur either negatively or positively regulates multiple important physiological functions in Xv. PMID:26910324

  1. Using Crystal Structure Groups to Understand Mssbauer parameters of Ferric Sulfates

    NASA Astrophysics Data System (ADS)

    Knutson, J.; Dyar, M. D.; Sklute, E. C.; Lane, M. D.; Bishop, J. L.

    2008-12-01

    A Mssbauer doublet assigned to ferric sulfate (Fe3D2) was identified in Paso Robles, Mars, spectra by Morris et al. (2006), who noted that its parameters are not diagnostic of any specific mineral because a number of different sulfates with varying parageneses might be responsible for this doublet. Work by Lane et al. (2008) used a multi-instrument approach based on Fe3+ sulfate spectra acquired with VNIR and midinfrared reflectance, mid-infrared emission and Mssbauer spectrometers to narrow down the possible ferric sulfate phases present at Paso Robles to ferricopiapite possibly mixed with other ferric sulfates such as butlerite, parabutlerite, fibroferrite, or metahomanite. Thus, we explore here the crystal-chemical rationale behind these interpretations of the Mssbauer results, using similarities and difference among mineral structures to explore which phases might have similar coordination polyhedra around the Fe atoms in sulfates. Work by Hawthorne et al. (2000) organizes the sulfate minerals into groups with analogous crystal structures. Mssbauer doublets assigned to ferric sulfates ubiquitously have isomer shifts (IS) of 0.40-53 mm/s so that IS is non-diagnostic. However, quadrupole splitting of doublets in these mineral groups has a wide range (0-1.4 mm/s) and the variation can be systematically correlated with different structure types. Members of the hydration series Fe2(SO4)3 n H2O, which includes quenstedtite, coquimbite, paracoquimbite, kornelite, and lausenite have Mssbauer spectra that closely resemble singlets because of their near-zero QS. These minerals share structures involving finite clusters of sulfate tetrahedral and Fe octahedral or chains of depolymerized clusters, and all mineral species with these structures share similar Mssbauer parameters. At the other extreme, ferric sulfates with structures based on infinite sheets (hydrotalcite, alunite, jarosite), tend to have large electric field gradients at the nucleus of the Fe3+ cation, resulting in larger QS values (1-1.4 mm/s). Between these extremes of QS are two populations of structures based on finite clusters of polyhedra with QS = 0.36-0.80 mm/s (coquimbite, rmerite, halotrichite, rozenite) and infinite chains with QS = 0.70-0.97 mm/s (chalcanthite, butlerite, fibroferrite, metahomanite). Our fits to the Paso Robles sol 429A data show two ferric doublets, both with IS = 0.42-0.43 mm/s but with differing QS = 0.36 and 0.93 mm/s; these parameters rule out mineral structures that have spectra with very high or very low QS. Ferric sulfates with structures composed of finite clusters and infinite chains thus provide the closest matches to the Paso Robles Mssbauer doublets, as well as spectra of other bright soils. Further constraints provided by other types of spectroscopy are then needed to determine which species within these structure groups are present. As additional sulfate structures are characterized, it will be possible to better understand the interrelationships among sulfate crystal structures and their spectral characteristics may provide additional constraints on mineral identification from ferric materials of all types. Morris et al. (2006) JGR, 111, doi: 10.1029/2005JE002584. Lane et al. (2008) Amer. Mineral., 93, 738-739. Hawthorne et al. (2000) Revs. Mineral., 40, 1-112.

  2. Electrical and optical properties of ferric doped PVA-PVP-PPy composite films

    NASA Astrophysics Data System (ADS)

    Patil, Ravikumar V.; Ranganath, M. R.; Lobo, Blaise

    2013-02-01

    The analysis of experimental optical spectra & electrical properties of PVA-PVP-PPy composite films is discussed in this paper. The optical parameters like activation energy of optical transitions and the optical band gap for direct and indirect allowed transitions were determined for PVA-PVP-PPy composite films doped with different concentrations of ferric chloride. The optical band gap showed best fit for indirect allowed transitions, and there is a decrease in the optical band gap with increase in concentration of ferric chloride. The DC electrical properties of these films indicated agreement with Mott's Variable Range Hopping Model in three dimensions. The width of the forbidden band gap was determined from the Arrhenius relation after experimentally studying in-situ, the variation of DC electrical conductivity with temperature.

  3. Repeat radiation synovectomy with dysprosium 165-ferric hydroxide macroaggregates in rheumatoid knees unresponsive to initial injection

    SciTech Connect

    Vella, M.; Zuckerman, J.D.; Shortkroff, S.; Venkatesan, P.; Sledge, C.B.

    1988-06-01

    Because of failure to fully respond to an initial intraarticular injection of dysprosium 165-ferric hydroxide macroaggregates, 17 patients with seropositive rheumatoid arthritis underwent repeat radiation synovectomy using this agent. Of the 13 patients who were evaluated 1 year later, 54% (7 knees) had good results, 31% (4 knees) had fair results, and 15% (2 knees) had poor results. The initial lack of significant benefit from radiation synovectomy did not appear to preclude a favorable response to a second injection.

  4. Microscale speciation of arsenic and iron in ferric-based sorbents subjected to simulated landfill conditions.

    PubMed

    Root, Robert A; Fathordoobadi, Sahar; Alday, Fernando; Ela, Wendell; Chorover, Jon

    2013-11-19

    During treatment for potable use, water utilities generate arsenic-bearing ferric wastes that are subsequently dispatched to landfills. The biogeochemical weathering of these residuals in mature landfills affects the potential mobilization of sorbed arsenic species via desorption from solids subjected to phase transformations driven by abundant organic matter and bacterial activity. Such processes are not simulated with the toxicity characteristic leaching procedure (TCLP) currently used to characterize hazard. To examine the effect of sulfate on As retention in landfill leachate, columns of As(V) loaded amorphous ferric hydroxide were reacted biotically at two leachate sulfate concentrations (0.064 mM and 2.1 mM). After 300 days, ferric sorbents were reductively dissolved. Arsenic released to porewaters was partially coprecipitated in mixed-valent secondary iron phases whose speciation was dependent on sulfate concentration. As and Fe XAS showed that, in the low sulfate column, 75-81% of As(V) was reduced to As(III), and 53-68% of the Fe(III) sorbent was transformed, dominantly to siderite and green rust. In the high sulfate column, Fe(III) solids were reduced principally to FeS(am), whereas As(V) was reduced to a polymeric sulfide with local atomic structure of realgar. Multienergy micro-X-ray fluorescence (ME-?XRF) imaging at Fe and As K-edges showed that As formed surface complexes with ferrihydrite > siderite > green rust in the low sulfate column; while discrete realgar-like phases formed in the high sulfate systems. Results indicate that landfill sulfur chemistry exerts strong control over the potential mobilization of As from ferric sorbent residuals by controlling secondary As and Fe sulfide coprecipitate formation. PMID:24102155

  5. Microscale speciation of arsenic and iron in ferric-based sorbents subjected to simulated landfill conditions

    PubMed Central

    Root, Robert A.; Fathordoobadi, Sahar; Alday, Fernando; Ela, Wendell; Chorover, Jon

    2013-01-01

    During treatment for potable use, water utilities generate arsenic-bearing ferric wastes that are subsequently dispatched to landfills. The biogeochemical weathering of these residuals in mature landfills affects the potential mobilization of sorbed arsenic species via desorption from solids subjected to phase transformations driven by abundant organic matter and bacterial activity. Such processes are not simulated with the Toxicity Characteristic Leaching Procedure (TCLP) currently used to characterize hazard. To examine the effect of sulfate on As retention in landfill leachate, columns of As(V) loaded amorphous ferric hydroxide were reacted biotically at two leachate sulfate concentrations (0.064 mM and 2.1 mM). After 300 d, ferric sorbents were reductively dissolved. Arsenic released to porewaters was partially co-precipitated in mixed-valent secondary iron phases whose speciation was dependent on sulfate concentration. As and Fe XAS showed that, in the low sulfate column, 7581% of As(V) was reduced to As(III), and 5368% of the Fe(III) sorbent was transformed, dominantly to siderite and green rust. In the high sulfate column, Fe(III) solids were reduced principally to FeS(am), whereas As(V) was reduced to a polymeric sulfide with local atomic structure of realgar. Multi-energy micro-X-ray fluorescence (ME-?XRF) imaging at Fe and As K-edges showed that As formed surface complexes with ferrihydrite > siderite > green rust in the low sulfate column; while discrete realgar-like phases formed in the high sulfate systems. Results indicate that landfill sulfur chemistry exerts strong control over the potential mobilization of As from ferric sorbent residuals by controlling secondary As and Fe sulfide co-precipitate formation. PMID:24102155

  6. The Ferric Enterobactin Transporter Fep Is Required for Persistent Salmonella enterica Serovar Typhimurium Infection

    PubMed Central

    Moreland, Sarah M.; Andrews-Polymenis, Helene; Detweiler, Corrella S.

    2013-01-01

    Most bacterial pathogens require iron to grow and colonize host tissues. The Gram-negative bacterium Salmonella enterica serovar Typhimurium causes a natural systemic infection of mice that models acute and chronic human typhoid fever. S. Typhimurium resides in tissues within cells of the monocyte lineage, which limit pathogen access to iron, a mechanism of nutritional immunity. The primary ferric iron import system encoded by Salmonella is the siderophore ABC transporter FepBDGC. The Fep system has a known role in acute infection, but it is unclear whether ferric iron uptake or the ferric iron binding siderophores enterobactin and salmochelin are required for persistent infection. We defined the role of the Fep iron transporter and siderophores in the replication of Salmonella in macrophages and in mice that develop acute followed by persistent infections. Replication of wild-type and iron transporter mutant Salmonella strains was quantified in cultured macrophages, fecal pellets, and host tissues in mixed- and single-infection experiments. We show that deletion of fepB attenuated Salmonella replication and colonization within macrophages and mice. Additionally, the genes required to produce and transport enterobactin and salmochelin across the outer membrane receptors, fepA and iroN, are needed for colonization of all tissues examined. However, salmochelin appears to be more important than enterobactin in the colonization of the spleen and liver, both sites of dissemination. Thus, the FepBDGC ferric iron transporter and the siderophores enterobactin and salmochelin are required by Salmonella to evade nutritional immunity in macrophages and cause persistent infection in mice. PMID:23959718

  7. Purification of two muscle enzymes by chromatography on immobilized ferric ions.

    PubMed

    Chaga, G; Andersson, L; Ersson, B; Porath, J

    1989-08-01

    Two enzymes, glycogen phosphorylase and lactate dehydrogenase, were purified simultaneously in a single step. Ferric ions immobilized on a chelating gel were used as the adsorbent. Adsorption and desorption steps were accomplished by changes in buffer composition. The recoveries were better than 80% and the capacities were about 5 mg of protein per milliliter of adsorbent. The procedure worked well both on a small and on a preparative scale. The homogeneity of the purified enzymes was checked by FPLC. PMID:2775499

  8. Inhibition of sulfate-reducing and methanogenic activities of anaerobic sewer biofilms by ferric iron dosing.

    PubMed

    Zhang, Lishan; Keller, Jrg; Yuan, Zhiguo

    2009-09-01

    Ferric iron is commonly used for sulfide precipitation in sewers, thus achieving corrosion and odour control. Its impact on the activities of sulfate-reducing bacteria and methanogens in anaerobic sewer biofilms is investigated in this study. Two lab-scale rising main sewer systems fed with real sewage were operated for 8 months. One received Fe(3+) dosage (experimental system) and the other was used as a control. In addition to precipitating sulfide from bulk water, Fe(3+) dosage was found to significantly inhibit sulfate reduction and methane production by sewer biofilms. The experimental reactor discharged an effluent containing a higher concentration of sulfate and a lower concentration of methane in comparison with the reference reactor. Batch experiments showed that the addition of ferric ions reduced the sulfate reduction and methane production rates of the sewer biofilms by 60% and 80%, respectively. The batch experiments further showed that Fe(3+) dosage changed the final products of sulfate reduction with sulfide accounting for only 54% of the sulfate reduced. The other products could not be confirmed, but were not dissolved inorganic sulfur species such as sulfite or thiosulfate. The results suggest the addition of Fe(3+) at upstream locations would minimize the ferric salts required for achieving the same level of sulfide removal. Fe(3+) dosing could also substantially reduce the formation of methane, a potent greenhouse gas, in sewers. PMID:19576610

  9. Evolution of the Ferric Reductase Domain (FRD) Superfamily: Modularity, Functional Diversification, and Signature Motifs

    PubMed Central

    Zhang, Xuezhi; Krause, Karl-Heinz; Xenarios, Ioannis; Soldati, Thierry; Boeckmann, Brigitte

    2013-01-01

    A heme-containing transmembrane ferric reductase domain (FRD) is found in bacterial and eukaryotic protein families, including ferric reductases (FRE), and NADPH oxidases (NOX). The aim of this study was to understand the phylogeny of the FRD superfamily. Bacteria contain FRD proteins consisting only of the ferric reductase domain, such as YedZ and short bFRE proteins. Full length FRE and NOX enzymes are mostly found in eukaryotic cells and all possess a dehydrogenase domain, allowing them to catalyze electron transfer from cytosolic NADPH to extracellular metal ions (FRE) or oxygen (NOX). Metazoa possess YedZ-related STEAP proteins, possibly derived from bacteria through horizontal gene transfer. Phylogenetic analyses suggests that FRE enzymes appeared early in evolution, followed by a transition towards EF-hand containing NOX enzymes (NOX5- and DUOX-like). An ancestral gene of the NOX(1-4) family probably lost the EF-hands and new regulatory mechanisms of increasing complexity evolved in this clade. Two signature motifs were identified: NOX enzymes are distinguished from FRE enzymes through a four amino acid motif spanning from transmembrane domain 3 (TM3) to TM4, and YedZ/STEAP proteins are identified by the replacement of the first canonical heme-spanning histidine by a highly conserved arginine. The FRD superfamily most likely originated in bacteria. PMID:23505460

  10. Experimental determination of the phase boundary between kornelite and pentahydrated ferric sulfate at 0.1MPa

    USGS Publications Warehouse

    Kong, W.G.; Wang, A.; Chou, I.-Ming

    2011-01-01

    Recent findings of various ferric sulfates on Mars emphasize the importance of understanding the fundamental properties of ferric sulfates at temperatures relevant to that of Martian surface. In this study, the phase boundary between kornelite (Fe2(SO4)3.7H2O) and pentahydrated ferric sulfate (Fe2(SO4)3.5H2O) was experimentally determined using the humidity-buffer technique together with gravimetric measurements and Raman spectroscopy at 0.1MPa in the 36-56??C temperature range. Through the thermodynamic analysis of our experimental data, the enthalpy change (-290.8??0.3kJ/mol) and the Gibbs free energy change (-238.82??0.02kJ/mol) for each water molecule of crystallization in the rehydration of pentahydrated ferric sulfate to kornelite were obtained. ?? 2011 Elsevier B.V.

  11. Addition of citrate to Acidithiobacillus ferrooxidans cultures enables precipitate-free growth at elevated pH and reduces ferric inhibition.

    PubMed

    Li, Xiaozheng; Mercado, Roel; Kernan, Timothy; West, Alan C; Banta, Scott

    2014-10-01

    Acidithiobacillus ferrooxidans is an acidophilic chemolithoautotroph that is important in biomining and other biotechnological operations. The cells are able to oxidize inorganic iron, but the insolubility and product inhibition by Fe(3+) complicates characterization of these cultures. Here we explore the growth kinetics of A. ferrooxidans in iron-based medium in a pH range from 1.6 to 2.2. It was found that as the pH was increased from 1.6 to 2.0, the maintenance coefficient decreased while both the growth kinetics and maximum cell yield increased in the precipitate-free, low Fe(2+) concentration medium. In higher iron media a similar trend was observed at low pH, but the formation of precipitates at higher pH (2.0) hampered cell growth and lowered the specific growth rate and maximum cell yield. In order to eliminate ferric precipitates, chelating agents were introduced into the medium. Citric acid was found to be relatively non-toxic and did not appear to interfere with iron oxidation at a maximum concentration of 70 mM. Inclusion of citric acid prevented precipitation and A. ferrooxidans growth parameters resumed their trends as a function of pH. The addition of citrate also decreased the apparent substrate saturation constant (KS ) indicating a reduction in the competitive inhibition of growth by ferric ions. These results indicate that continuous cultures of A. ferrooxidans in the presence of citrate at elevated pH will enable enhanced cell yields and productivities. This will be critical as these cells are used in the development of new biotechnological applications such as electrofuel production. PMID:24771134

  12. Determination of iron-ligand bond lengths in ferric and ferrous horse heart cytochrome c using multiple-scattering analyses of XAFS data

    SciTech Connect

    Cheng, M.C.; Rich, A.M.; Armstrong, R.S.; Ellis, P.J.; Lay, P.A.

    1999-12-13

    Cytochrome c (cyt c) is a small heme protein (MW 12 384) that functions as a biological electron-transfer agent. It consists of a single polypeptide chain and a prosthetic heme group and provides a pathway for the transfer of electrons from cyt c reductase to cyt c oxidase in the mitochondrial respiratory chain (oxidative phosphorylation). The protein participates in oxidation-reduction reactions with the heme iron alternating between the oxidized (ferric, Fe{sup III}) state and the reduced (ferrous, Fe{sup II}) state. X-ray absorption fine structure (XAFS) data were obtained from frozen aqueous solutions (10 K) of horse heart ferri- and ferrocyt c. Models of the structure about the Fe center were refined to optimize the fit between the observed XAFS in the range 0 {le} k {le} 16.3 {angstrom}{sup {minus}1} and the XAFS calculated using both single-scattering (SS) and multiple-scattering (MS) calculations. The bond lengths obtained are more accurate and precise than those determined previously for cyt c from various species using X-ray crystallography. The Fe-N bond lengths are 1.98--1.99 {angstrom} for both oxidation states of cyt c. The Fe-S bond of derricyt c (2.33 {angstrom}) is significantly longer than that of ferrocyt c (2.29 {angstrom}). The small changes in the bond lengths are consistent with the small reorganizational energy required for the fast electron-transfer reaction of cyt c.

  13. Ferric Iron Precipitation in the Nagahama Bay, Satsuma Iwo-Jima Island, Kagoshima

    NASA Astrophysics Data System (ADS)

    Nagata, T.; Kiyokawa, S.; Ikehara, M.; Oguri, K.; Goto, S.; Ito, T.; Yamaguchi, K. E.; Ueshiba, T.

    2010-12-01

    Satsuma-Iwojima island is active volcanic island and 6 x 3 km in size, located 38km south of Kyushu island, Japan. The reddish brown water along the coast of the Iwo-dake volcano at the center of the island formed by neutralization through mixing of shallow hydrothermal fluid and seawater. The reddish brown water contains reddish ferrihydrite (Fe3+) that is derived from oxidation of Fe2+ from acidic hot spring (Shikaura and Tazaki, 2001). In the Nagahama Bay with its opening to the south, red-colored Fe-rich water is affected by tidal current, but sedimentation of the ferric hydroxide is confirmed to occur in the ocean bottom (Ninomiya and Kiyokawa, 2009). Here we focus other lines of evidence from long term observations and meteorological records as important factor to form thick iron rich sediments. Meteorological and stationary observations: We used weather record in the Satsuma Iwo-jima and cross-checked with stationary observations, which enabled us to observe color changes of the surface of Nagahama Bay. It was made clear that north wind condition in the Nagahama Bay resulted in changes of the color of its surface, from red to green, by intrusion of ocean water coming from outside. Long term temperature monitoring: The temperature of seawater in the Nagahama Bay fluctuated synchronically with the air temperature. But that of hot spring water rather remained constant regardless of the seasonal change. We observed that seawater temperature in the Nagahama Bay is low at high tide and high at low tide, and the rage of temperature change is maximum at the spring tide and minimum at the neap tide. In other words, the amount of discharge of hot spring and that of seawater inflow vary inversely. Core sample: In the Nagahama Bay, iron rich sediments that is more than 1 m thick were identified. The core sample shows lithology as following; upper part, 10-20cm thick, formed loose Fe-rich deposit, lower portion formed alteration of weakly consolidated Fe-rich orange-colored mud, the organic-rich black mud and volcanic ash layers. The basal part has distinctive pink ash layer, which was identified as 1997 volcanic activity. Therefore, the core samples have records of the past 12 years and show average deposition rate of 8cm/year. Sediment trap: There accumulated 7.5cm-thick materials, dominated by ferrihydrite, during the 82 days experiment (2009/July/12~Oct./03). Sedimentation rate is 2.8cm/month (33.3cm/year). Estimated deposition rate of the core sample is 8cm/year. These differences suggest that about three-forth of Fe-hydroxide formed the Nagahama Bay would have been flashed to the open ocean by tidal and storm effects. These lines of evidence suggest that neap tide supports relatively quiet and has enough supply of hot spring into seawater and south wind works as a cap. The fine-grained iron Fe-hydroxide in the Nagahama Bay is provided and deposited at neap tide and south wind condition.

  14. Simulation of Space Weathering by Nanosecond Pulse Laser Irradiation: Spectral Change and TEM-ESR Confirmation of Nanophase Iron Particles

    NASA Astrophysics Data System (ADS)

    Sasaki, S.; Kurahashi, E.; Nakamura, K.; Hiroi, T.; Yamanaka, C.

    2002-01-01

    In 1975, while examining why lunar regolith becomes darker and redder with time, Bruce Hapke with colleagues advocated that the lunar soil grains should have been coated with vapor-deposited rim containing nanometer-sized iron particles. High-velocity dust impacts and/or solar wind irradiations might produce ferrous silicate vapor. This process is called 'space weathering'. However, this hypothesis had been ignored until nanophase iron particles were confirmed in lunar regolith grains by TEM. S-type asteroids, majority in asteroids, are believed to be parent bodies of ordinary chondrites, which are a large majority in meteorites. However, S-type steroids exhibit more overall depletion and reddening of spectra, and more weakening of absorption bands relative to ordinary chondrites. This spectral mismatch is also considered being caused by space weathering process. Recent observation by Galileo showed that fresh crater interior and ejecta on S-type Ida have the spectra closer to that of ordinary chondrites. Some small asteroids have intermediate spectra between S-type and Q-type (ordinary-chondrite like) spectra. NEAR's X-ray spectrometer showed that S-type 433 Eros has elemental composition close to ordinary chondrites.

  15. Thermal and Evolved Gas Analysis of "Nanophase" Carbonates: Implications for Thermal and Evolved Gas Analysis on Mars Missions

    NASA Technical Reports Server (NTRS)

    Lauer, Howard V., Jr.; Archer, P. D., Jr.; Sutter, B.; Niles, P. B.; Ming, Douglas W.

    2012-01-01

    Data collected by the Mars Phoenix Lander's Thermal and Evolved Gas Analyzer (TEGA) suggested the presence of calcium-rich carbonates as indicated by a high temperature CO2 release while a low temperature (approx.400-680 C) CO2 release suggested possible Mg- and/or Fe-carbonates [1,2]. Interpretations of the data collected by Mars remote instruments is done by comparing the mission data to a database on the thermal properties of well-characterized Martian analog materials collected under reduced and Earth ambient pressures [3,4]. We are proposing that "nano-phase" carbonates may also be contributing to the low temperature CO2 release. The objectives of this paper is to (1) characterize the thermal and evolved gas proper-ties of carbonates of varying particle size, (2) evaluate the CO2 releases from CO2 treated CaO samples and (3) examine the secondary CO2 release from reheated calcite of varying particle size.

  16. Low-temperature reflectivity spectra of red hematite and the color of Mars

    NASA Astrophysics Data System (ADS)

    Morris, Richard V.; Golden, D. C.; Bell, James F.

    1997-04-01

    Reflectivity spectra (visible and near IR) were measured near 141, 210, and 300 K for four red and well-crystalline powders of hematite (red hematite) used as commercial pigments, two samples of volcanic tephra from Mauna Kea volcano that contain red hematite as their dominant pigment, three samples of palagonitic tephra from the same location that contain nanophase ferric oxide as their dominant pigment, and two mixtures of the two types of pigmenting phases. Relative proportions of red hematite and nanophase ferric oxide were determined by Mssbauer spectroscopy. For samples containing red hematite as the dominant pigment, the positions of the ferric electronic transitions near 430, 500, 630, and 860 nm are essentially independent of temperature, but their widths decrease with decreasing temperature. This decrease results in a well-defined minimum for the band at 630 nm at low temperatures and in significant increases in reflectivity in spectral regions near 1050 and 600 nm. For example, the reflectivity ratios R600/R530 and R600/R860 both increase by a factor as large as ~1.4 between 300 and 140 K. The spectral features from nanophase ferric oxide in samples of palagonitic tephra are nearly independent of temperature. Spectral data of Martian bright regions that are characterized by a shallow band minimum near 860 nm, a reflectivity maximum near 740 nm, a distinct bend near 600 nm, and a shallow absorption edge from ~400 to 740 nm are attributed to the presence of nanophase ferric oxide plus subordinate amounts of red hematite. The 600-, 740-, and 860-nm features are associated with red hematite. Because the reflectivity of red hematite at 600 nm is strongly dependent on temperature and because this wavelength is in the red part of the visible spectrum, the color of the Martian surface may vary as a function of its temperature. A conservative upper limit for the red hematite content of the optical surface of Mars is 5%.

  17. Cost-utility of ferric carboxymaltose (Ferinject) for iron-deficiency anemia patients with chronic heart failure in South Korea

    PubMed Central

    2014-01-01

    Background Iron-deficiency anemia (IDA) is prevalent in patients with advanced chronic heart failure (CHF). It affects the patients overall physical condition and is suggested as a strong outcome predictor in CHF. Recent clinical trials suggested that intravenous iron supplementation improves CHF functional status and quality of life. The aim of this study was to assess the cost-effectiveness of ferric carboxymaltose(FCM) in CHF patients with IDA. Methods Ferric carboxymaltose, an intravenous iron preparation, was compared with placebo. The target population comprised CHF patients with IDA in hospital and outpatient care settings. We conducted this study from the Korean healthcare payers perspective with a time horizon of 24weeks. One clinical trial provided the clinical outcomes of ferric carboxymaltose therapy. The improvement rates of the New York Heart Association (NYHA) functional class in the placebo and ferric carboxymaltose groups were used to estimate effectiveness in the base-case model. We also conducted a scenario 2 analysis using quality of life investigated in the clinical trial. A panel survey was conducted to obtain the ratio of healthcare resource use based on NYHA class in Korea. Cost-effectiveness was expressed as incremental cost (US dollars) per quality-adjusted life-year (QALY) gained. Results In the base-case analysis, the incremental cost-effectiveness ratio (ICER) of ferric carboxymaltose compared with placebo was $22,192 (?25,010,451) per QALY gained. The sensitivity analysis showed robust results, with the ICERs of ferric carboxymaltose ranging from $5,156 to $29,796 per QALY gained. In the scenario 2 analysis, ICER decreased to $12,598 (?14,198,501) per QALY gained. Conclusions Iron repletion with ferric carboxymaltose for IDA in CHF patients was cost-effective compared with placebo. PMID:25278814

  18. Ferric Citrate

    PubMed Central

    Cada, Dennis J.; Cong, Jasen; Baker, Danial E.

    2015-01-01

    Each month, subscribers to The Formulary Monograph Service receive 5 to 6 well-documented monographs on drugs that are newly released or are in late phase 3 trials. The monographs are targeted to Pharmacy & Therapeutics Committees. Subscribers also receive monthly 1-page summary monographs on agents that are useful for agendas and pharmacy/nursing in-services. A comprehensive target drug utilization evaluation/medication use evaluation (DUE/MUE) is also provided each month. With a subscription, the monographs are sent in print and are also available on-line. Monographs can be customized to meet the needs of a facility. A drug class review is now published monthly with The Formulary Monograph Service. Through the cooperation of The Formulary, Hospital Pharmacy publishes selected reviews in this column. For more information about The Formulary Monograph Service, call The Formulary at 800-322-4349. The February 2015 monograph topics are netupitant/palonosetron, naltrxone SR/bupropion SR, nintedanib, pirfenidone, and ivabradine. The Safety MUE is on netupitant/palonosetron. PMID:25717210

  19. Ferric citrate.

    PubMed

    Cada, Dennis J; Cong, Jasen; Baker, Danial E

    2015-02-01

    Each month, subscribers to The Formulary Monograph Service receive 5 to 6 well-documented monographs on drugs that are newly released or are in late phase 3 trials. The monographs are targeted to Pharmacy & Therapeutics Committees. Subscribers also receive monthly 1-page summary monographs on agents that are useful for agendas and pharmacy/nursing in-services. A comprehensive target drug utilization evaluation/medication use evaluation (DUE/MUE) is also provided each month. With a subscription, the monographs are sent in print and are also available on-line. Monographs can be customized to meet the needs of a facility. A drug class review is now published monthly with The Formulary Monograph Service. Through the cooperation of The Formulary, Hospital Pharmacy publishes selected reviews in this column. For more information about The Formulary Monograph Service, call The Formulary at 800-322-4349. The February 2015 monograph topics are netupitant/palonosetron, naltrxone SR/bupropion SR, nintedanib, pirfenidone, and ivabradine. The Safety MUE is on netupitant/palonosetron. PMID:25717210

  20. Ferric ammonium citrate decomposition--a taxonomic tool for gram-negative bacteria.

    PubMed

    Szentmihályi, A; Lányi, B

    1986-01-01

    The iron uptake test of Szabó and Vandra has been modified and used for the differentiation of Gram-negative bacteria. Nutrient agar containing 20 g per litre of ferric ammonium citrate was distributed into narrow tubes and solidified so as to form butts and slants. Considering the localization of the rusty-brown coloration produced after seeding and incubation, 2367 strains were classified into four groups. (1) Unchanged medium: Escherichia coli, Shigella spp., Yersinia spp., Hafnia alvei and Morganella morganii 100% each, Klebsiella spp., 50%, Enterobacter cloacae 37%, Proteus vulgaris 59%, Acinetobacter spp. 42%, Pseudomonas fluorescens 19%, some other bacteria 2-12%. (2) Rusty-brown slant, unchanged butt: Salmonella subgenera II, III and IV 98%, Citrobacter freundii 65%, E. cloacae 55%, P. vulgaris 41%, Proteus mirabilis 98%, Providencia rettgeri 100%, urease-negative Providencia 96%, Acinetobacter spp. 58%, Pseudomonas aeruginosa 100%, P. fluorescens 81%, UFP (unclassified fluorescent pseudomonads) 100%, other Pseudomonas spp. 55%. (3) Unchanged slant, brown butt: S. typhi 88%, Salmonella subgenus I 3%, Klebsiella spp. 31%, some other bacteria 2-3%. (4) Rusty-brown slant, brown butt: Salmonella subgenus I 75%, C. freundii 20%, Klebsiella spp. 12%, some other bacteria 1-5%. Colour reactions in ferric ammonium citrate agar are associated with the accumulation of ferric hydroxide: bacteria giving positive reactions on the slant took up as an average, 63 times more iron than those with negative test. The localization of colour reaction correlated partly with aerobic and anaerobic citrate utilization or decomposition in Simmons' minimal and in Kauffmann's peptone water medium. PMID:3529797

  1. Ferric iron reduction by bacteria associated with the roots of freshwater and marine macrophytes.

    PubMed

    King, G M; Garey, M A

    1999-10-01

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

  2. Carboxylate free ?-oxo bridged ferric wheel with a record exchange coupling.

    PubMed

    Ahmed, Naushad; Upadhyay, Apoorva; Rajeshkumar, Thayalan; Vaidya, Shefali; Schnack, Jrgen; Rajaraman, Gopalan; Shanmugam, Maheswaran

    2015-10-27

    A novel oxo-bridged, carboxylate free 'ferric wheel' was isolated with the molecular formula [Fe(?-O)4(L(2-))8] (). Magnetic susceptibility measurements suggest that the Fe(iii) ions are coupled antiferromagnetically and magnetic data modelling yields J1 = -26.4 cm(-1), J2 = -170 cm(-1) which are rationalized by DFT calculation. The exchange value for of -170 cm(-1) (Fe-O(oxo)-Fe) is the largest exchange value known compared to any homometallic or heterometallic wheel reported to date. PMID:26479520

  3. Surface topology of the Escherichia coli K-12 ferric enterobactin receptor.

    PubMed Central

    Murphy, C K; Kalve, V I; Klebba, P E

    1990-01-01

    Monoclonal antibodies (MAb) were raised to the Escherichia coli K-12 ferric enterobactin receptor, FepA, and used to identify regions of the polypeptide that are involved in interaction with its ligands ferric enterobactin and colicins B and D. A total of 11 distinct FepA epitopes were identified. The locations of these epitopes within the primary sequence of FepA were mapped by screening MAb against a library of FepA::PhoA fusion proteins, a FepA deletion mutant, and proteolytically modified FepA. These experiments localized the 11 epitopes to seven different regions within the FepA polypeptide, including residues 2 to 24, 27 to 37, 100 to 178, 204 to 227, 258 to 290, 290 to 339, and 382 to 400 of the mature protein. Cell surface-exposed epitopes of FepA were identified and discriminated by cytofluorimetry and by the ability of MAb that recognize them to block the interaction of FepA with its ligands. Seven surface epitopes were defined, including one each in regions 27 to 37, 204 to 227, and 258 to 290 and two each in regions 290 to 339 and 382 to 400. One of these, within region 290 to 339, was recognized by MAb in bacteria containing intact (rfa+) lipopolysaccharide (LPS); all other surface epitopes were susceptible to MAb binding only in a strain containing a truncated (rfaD) LPS core, suggesting that they are physically shielded by E. coli K-12 LPS core sugars. Antibody binding to FepA surface epitopes within region 290 to 339 or 382 to 400 inhibited killing by colicin B or D and the uptake of ferric enterobactin. In addition to the FepA-specific MAb, antibodies that recognized other outer membrane components, including Cir, OmpA, TonA, and LPS, were identified. Immunochemical and biochemical characterization of the surface structures of FepA and analysis of its hydrophobicity and amphilicity were used to generate a model of the ferric enterobactin receptor's transmembrane strands, surface peptides, and ligand-binding domains. Images PMID:2139651

  4. Resonant Inelastic X-ray Scattering on Ferrous and Ferric Bis-imidazole Porphyrin and Cytochrome c: Nature and Role of the Axial MethionineFe Bond

    PubMed Central

    2015-01-01

    Axial CuS(Met) bonds in electron transfer (ET) active sites are generally found to lower their reduction potentials. An axial S(Met) bond is also present in cytochrome c (cyt c) and is generally thought to increase the reduction potential. The highly covalent nature of the porphyrin environment in heme proteins precludes using many spectroscopic approaches to directly study the Fe site to experimentally quantify this bond. Alternatively, L-edge X-ray absorption spectroscopy (XAS) enables one to directly focus on the 3d-orbitals in a highly covalent environment and has previously been successfully applied to porphyrin model complexes. However, this technique cannot be extended to metalloproteins in solution. Here, we use metal K-edge XAS to obtain L-edge like data through 1s2p resonance inelastic X-ray scattering (RIXS). It has been applied here to a bis-imidazole porphyrin model complex and cyt c. The RIXS data on the model complex are directly correlated to L-edge XAS data to develop the complementary nature of these two spectroscopic methods. Comparison between the bis-imidazole model complex and cyt c in ferrous and ferric oxidation states show quantitative differences that reflect differences in axial ligand covalency. The data reveal an increased covalency for the S(Met) relative to N(His) axial ligand and a higher degree of covalency for the ferric states relative to the ferrous states. These results are reproduced by DFT calculations, which are used to evaluate the thermodynamics of the FeS(Met) bond and its dependence on redox state. These results provide insight into a number of previous chemical and physical results on cyt c. PMID:25475739

  5. Process for the synthesis of nanophase dispersion-strengthened aluminum alloy

    DOEpatents

    Barbour, John C. (Albuquerque, NM); Knapp, James Arthur (Albuquerque, NM); Follstaedt, David Martin (Albuquerque, NM); Myers, Samuel Maxwell (Albuquerque, NM)

    1998-12-15

    A process for fabricating dispersion-strengthened ceramic-metal composites is claimed. The process comprises in-situ interaction and chemical reaction of a metal in gaseous form with a ceramic producer in plasma form. Such composites can be fabricated with macroscopic dimensions. Special emphasis is placed on fabrication of dispersion-strengthened aluminum oxide-aluminum composites, which can exhibit flow stresses more characteristic of high strength steel.

  6. Metal tungstates at the ultimate two-dimensional limit: fabrication of a CuWO₄ nanophase.

    PubMed

    Denk, Martin; Kuhness, David; Wagner, Margareta; Surnev, Svetlozar; Negreiros, Fabio R; Sementa, Luca; Barcaro, Giovanni; Vobornik, Ivana; Fortunelli, Alessandro; Netzer, Falko P

    2014-04-22

    Metal tungstates (with general formula MWO4) are functional materials with a high potential for a diverse set of applications ranging from low-dimensional magnetism to chemical sensing and photoelectrocatalytic water oxidation. For high level applications, nanoscale control of film growth is necessary, as well as a deeper understanding and characterization of materials properties at reduced dimensionality. We succeeded in fabricating and characterizing a two-dimensional (2-D) copper tungstate (CuWO4). For the first time, the atomic structure of an ultrathin ternary oxide is fully unveiled. It corresponds to a CuWO4 monolayer arranged in three sublayers with stacking O-W-O/Cu from the interface. The resulting bidimensional structure forms a robust framework with localized regions of anisotropic flexibility. Electronically it displays a reduced band gap and increased density of states close to the Fermi level with respect to the bulk compound. These unique features open a way for new applications in the field of photo- and electrocatalysis, while the proposed synthesis method represents a radically new and general approach toward the fabrication of 2-D ternary oxides. PMID:24617647

  7. In situ XANES Spectroscopic Investigation of the Pre-Reduction of Iron-Based Catalysts for Non-Oxidative Alkane Dehydrogenation

    SciTech Connect

    Huggins, F.; Shen, W; Cprek, N; Shah, N; Marinkovic, N; Huffman, G

    2008-01-01

    The reduction in a methane atmosphere of two as-prepared ferric oxide catalysts for the non-oxidative dehydrogenation of alkanes has been investigated by in situ X-ray absorption near-edge structure (XANES) spectroscopy using a novel X-ray transmission reaction cell. The two catalysts were prepared by different synthesis methods (incipient wetness and nanoparticle impregnation) and were supported on Al-substituted magnesium oxide obtained by decomposition of a synthetic hydrotalcite. The reduction of the ferric oxides by methane was followed by iron XANES spectroscopy at temperatures up to 650 C complemented by a residual gas analyzer (RGA) used to track changes in the product gas. Results showed that the ferric oxides in the two catalysts underwent a stepwise reduction to first ferrous oxide, releasing mainly H{sub 2}O in the case of the nanoparticle catalyst but H{sub 2} and CO in the case of the incipient wetness formulation at temperatures between 200 and 550 C, and then more slowly to metallic iron at higher temperatures. Reaction of the ferrous oxide with the support to form magnesiowstite also occurred in conjunction with the reduction. This in situ investigation confirms that metallic iron is the active catalytic phase for alkane dehydrogenation and that observations of ferric iron in samples investigated at room temperature after reduction and reaction are most likely due to re-oxidation of the iron in the catalyst upon exposure to air rather than incomplete reduction of the original ferric iron in the catalyst.

  8. Combining Ferric Salt and Cactus Mucilage for Arsenic Removal from Water.

    PubMed

    Fox, Dawn I; Stebbins, Daniela M; Alcantar, Norma A

    2016-03-01

    New methods to remediate arsenic-contaminated water continue to be studied, particularly to fill the need for accessible methods that can significantly impact developing communities. A combination of cactus mucilage and ferric (Fe(III)) salt was investigated as a flocculation-coagulation system to remove arsenic (As) from water. As(V) solutions, ferric nitrate, and mucilage suspensions were mixed and left to stand for various periods of time. Visual and SEM observations confirmed the flocculation action of the mucilage as visible flocs formed and settled to the bottom of the tubes within 3 min. The colloidal suspensions without mucilage were stable for up to 1 week. Sample aliquots were tested for dissolved and total arsenic by ICP-MS and HGAFS. Mucilage treatment improved As removal (over Fe(III)-only treatment); the system removed 75-96% As in 30 min. At neutral pH, removal was dependent on Fe(III) and mucilage concentration and the age of the Fe(III) solution. The process is fast, achieving maximum removal in 30 min, with the majority of As removed in 10-15 min. Standard jar tests with 1000 μg/L As(III) showed that arsenic removal and settling rates were pH-dependent; As removal was between 52% (high pH) and 66% (low pH). PMID:26824141

  9. Arsenic removal from high-arsenic water by enhanced coagulation with ferric ions and coarse calcite.

    PubMed

    Song, S; Lopez-Valdivieso, A; Hernandez-Campos, D J; Peng, C; Monroy-Fernandez, M G; Razo-Soto, I

    2006-01-01

    Arsenic removal from high-arsenic water in a mine drainage system has been studied through an enhanced coagulation process with ferric ions and coarse calcite (38-74 microm) in this work. The experimental results have shown that arsenic-borne coagulates produced by coagulation with ferric ions alone were very fine, so micro-filtration (membrane as filter medium) was needed to remove the coagulates from water. In the presence of coarse calcite, small arsenic-borne coagulates coated on coarse calcite surfaces, leading the settling rate of the coagulates to considerably increase. The enhanced coagulation followed by conventional filtration (filter paper as filter medium) achieved a very high arsenic removal (over 99%) from high-arsenic water (5mg/l arsenic concentration), producing a cleaned water with the residual arsenic concentration of 13 microg/l. It has been found that the mechanism by which coarse calcite enhanced the coagulation of high-arsenic water might be due to attractive electrical double layer interaction between small arsenic-borne coagulates and calcite particles, which leads to non-existence of a potential energy barrier between the heterogeneous particles. PMID:16352327

  10. Synovectomy of the rheumatoid knee using intra-articular injection of dysprosium-165-ferric hydroxide macroaggregates

    SciTech Connect

    Sledge, C.B.; Zuckerman, J.D.; Shortkroff, S.; Zalutsky, M.R.; Venkatesan, P.; Snyder, M.A.; Barrett, W.P.

    1987-09-01

    One hundred and eleven patients who had seropositive rheumatoid arthritis and persistent synovitis of the knee were treated with intra-articular injection of 270 millicuries of dysprosium-165 bound to ferric hydroxide macroaggregates. A two-year follow-up was available for fifty-nine of the treated knees. Thirty-nine had a good result; nine, a fair result; and eleven, a poor result. Of the twenty-five knees that had Stage-I radiographic changes, nineteen had a good result. Of the thirty-four knees that had Stage-II radiographic changes, twenty showed a good result. Systemic spread of the radioactivity from the injected joint was minimum. The mean whole-body dose was calculated to be 0.3 rad and that to the liver twenty-four hours after injection, 3.2 rads. The results indicated that dysprosium-165-ferric hydroxide macroaggregate is an effective agent for performing radiation synovectomy, particularly in knees that have Stage-I radiographic changes. Because of the minimum rate of systemic spread of the dysprosium-165, it offers a definite advantage over agents that previously have been used.

  11. Treatment of rheumatoid synovitis of the knee with intraarticular injection of dysprosium 165-ferric hydroxide macroaggregates

    SciTech Connect

    Sledge, C.B.; Zuckerman, J.D.; Zalutsky, M.R.; Atcher, R.W.; Shortkroff, S.; Lionberger, D.R.; Rose, H.A.; Hurson, B.J.; Lankenner, P.A. Jr.; Anderson, R.J.

    1986-02-01

    One hundred eight knees of 93 patients with seropositive rheumatoid arthritis and persistent synovitis of the knee were treated with an intraarticular injection of 270 mCi of dysprosium 165 bound to ferric hydroxide macroaggregate. Leakage of radioactivity from the injected joint was minimal. Mean leakage to the venous blood 3 hours after injection was 0.11% of the injected dose; this corresponds to a mean whole body dose of 0.2 rads. Mean leakage to the liver 24 hours after injection was 0.64% of the injected dose; this corresponds to a mean liver dose of 3.2 rads. In 7 additional patients examined, there was negligible or near negligible activity found in the draining inguinal lymph nodes. One-year followup was possible for 74 knees (63 patients). Sixty-one percent of the knees had good results, 23% had fair results, and 16% had poor results. There was a direct correlation between the radiographic stage and response to treatment. In knees with stage I radiographic changes, 72% showed good results; 93% showed improvement. In knees with stage II changes, 59% showed good results; 81% showed improvement. These preliminary results indicate that dysprosium 165-ferric hydroxide macroaggregate is an effective agent for radiation synovectomy. The low leakage rates observed offer a definite advantage over agents previously used.

  12. [Mechanism of groundwater As(V) removal with ferric flocculation and direct filtration].

    PubMed

    Kang, Ying; Duan, Jin-Ming; Jing, Chuan-Yong

    2015-02-01

    The As removal process and mechanism from groundwater using ferric flocculation-direct filtration system was investigated using batch, field pilot tests, extended X-ray absorption fine structure ( EXAFS) spectroscopy, and charge-distribution multisite complexation (CD-MUSIC) model. The results showed that arsenate [As(V)] was the dominant As species in the groundwater with a concentration of 40 ?g x L(-1). The treatment system could supply 64 984 L As-safe drinking water (< 10 ?g L(-1)) using Fe 1.5 mg x L(-1). Toxicity characteristic leaching procedure (TCLP) demonstrated that the leachate As was 3.4 ?g x L(-1), much lower than the EPA regulatory concentration (5 mg x L(-1)). EXAFS and CD-MUSIC model indicated that As(V) was adsorbed onto ferric hydroxide via bidentate binuclear complexes in the pH range of 3 to 9.5, while formation of precipitate with Ca or Mg dominated the As removal at pH > 9.5. PMID:26031078

  13. The ferric fluosilicate leaching of lead concentrates; Part 1: Kinetic studies

    SciTech Connect

    Chen, A.A.; Dreisinger, D.B. )

    1994-08-01

    Under the current pressure of strict environmental regulations, lead producers are seeking more efficient ways to produce lead. A new hydrometallurgical leaching process, which dissolves lead concentrates with acidified ferric fluosilicate solution, has been investigated for the selective extraction of lead and zinc from lead concentrates containing galena. The leaching of the Pine Point lead concentrate by ferric fluosilicate solutions was studied under various experimental conditions in the temperature range 20 C to 95 C. Temperature had a pronounced effect on the dissolution of the concentrates. The rates of lead leaching are very rapid over the temperature range 38 C to 95 C. The kinetics of zinc extraction are much lower than those of lead extraction. The reaction rates for the dissolution of galena were found to be controlled by surface chemical reaction. The apparent activation energy of the leaching reaction was calculated to be 62.1 kJ/mol. The initial concentrations of Pb[sup 2+], H[sup +], and Fe[sup 3+] in the lixiviant do not have a significant effect on the rate or extent of lead extraction under the experimental conditions in this study.

  14. Histoplasma capsulatum secreted ?-glutamyltransferase reduces iron by generating an efficient ferric reductant

    PubMed Central

    Zarnowski, Robert; Cooper, Kendal G.; Brunold, Laura Schmitt; Calaycay, Jimmy; Woods, Jon P.

    2008-01-01

    Summary The intracellular fungal pathogen Histoplasma capsulatum (Hc) resides in mammalian macrophages and causes respiratory and systemic disease. Iron limitation is an important host antimicrobial defense, and iron acquisition is critical for microbial pathogenesis. Hc displays several iron acquisition mechanisms, including secreted glutathione-dependent ferric reductase activity (GSH-FeR). We purified this enzyme from culture supernatant and identified a novel extracellular iron reduction strategy involving ?-glutamyltransferase (Ggt1) activity. The 320-kDa complex was composed of glycosylated protein subunits of about 50 and 37 kDa. The purified enzyme exhibited ?-glutamyl transfer activity as well as iron reduction activity in the presence of glutathione. We cloned and manipulated expression of the encoding gene. Overexpression or RNAi silencing affected both GGT and GSH-FeR activities concurrently. Enzyme inhibition experiments showed the activity is complex and involves two reactions. First, Ggt1 initiates enzymatic breakdown of GSH by cleavage of the ?-glutamyl bond and release of cysteinylglycine. Second, the thiol group of the released dipeptide reduces ferric to ferrous iron. A combination of kinetic properties of both reactions resulted in efficient iron reduction over a broad pH range. Our findings provide novel insight into Hc iron acquisition strategies and reveal a unique aspect of Ggt1 function in this dimorphic mycopathogen. PMID:18761625

  15. Ferric Citrate Hydrate as a Phosphate Binder and Risk of Aluminum Toxicity

    PubMed Central

    Gupta, Ajay

    2014-01-01

    Ferric citrate hydrate was recently approved in Japan as an oral phosphate binder to be taken with food for the control of hyperphosphatemia in patients with chronic kidney disease (CKD). The daily therapeutic dose is about 3 to 6 g, which comprises about 2 to 4 g of citrate. Oral citrate solubilizes aluminum that is present in food and drinking water, and opens the tight junctions in the intestinal epithelium, thereby increasing aluminum absorption and urinary excretion. In healthy animals drinking tap water, oral citrate administration increased aluminum absorption and, over a 4-week period, increased aluminum deposition in brain and bone by about 2- and 20-fold, respectively. Renal excretion of aluminum is impaired in patients with chronic kidney disease, thereby increasing the risk of toxicity. Based on human and animal studies it can be surmised that patients with CKD who are treated with ferric citrate hydrate to control hyperphosphatemia are likely to experience enhanced absorption of aluminum from food and drinking water, thereby increasing the risk of aluminum overload and toxicity. PMID:25341358

  16. 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

  17. Super adsorption capability from amorphousization of metal oxide nanoparticles for dye removal

    PubMed Central

    Li, L. H.; Xiao, J.; Liu, P.; Yang, G. W.

    2015-01-01

    Transitional metal oxide nanoparticles as advanced environment and energy materials require very well absorption performance to apply in practice. Although most metal oxides are based on crystalline, high activities can also be achieved with amorphous phases. Here, we reported the adsorption behavior and mechanism of methyl blue (MB) on the amorphous transitional metal oxide (Fe, Co and Ni oxides) nanoparticles, and we demonstrated that the amorphousization of transitional metal oxide (Fe, Co and Ni oxides) nanoparticles driven by a novel process involving laser irradiation in liquid can create a super adsorption capability for MB, and the maximum adsorption capacity of the fabricated NiO amorphous nanostructure reaches up to 10584.6 mgg−1, the largest value reported to date for all MB adsorbents. The proof-of-principle investigation of NiO amorphous nanophase demonstrated the broad applicability of this methodology for obtaining new super dyes adsorbents. PMID:25761448

  18. THE EFFECT OF OXIDANTS ON THE PROPERTIES OF FE (III) PARTICLES AND SUSPENSIONS FORMED FROM THE OXIDATION OF FE (II)

    EPA Science Inventory

    Oxidation of Fe(II) to Fe(III) is an important reaction in drinking water treatment and distribution systems, and the ferric particles that form are a major source of consumer complaints of colored water. Ferrous iron is found naturally in many ground waters and can be released ...

  19. Identification and characterization of a novel-type ferric siderophore reductase from a gram-positive extremophile.

    PubMed

    Miethke, Marcus; Pierik, Antonio J; Peuckert, Florian; Seubert, Andreas; Marahiel, Mohamed A

    2011-01-21

    Iron limitation is one major constraint of microbial life, and a plethora of microbes use siderophores for high affinity iron acquisition. Because specific enzymes for reductive iron release in gram-positives are not known, we searched Firmicute genomes and found a novel association pattern of putative ferric siderophore reductases and uptake genes. The reductase from the schizokinen-producing alkaliphile Bacillus halodurans was found to cluster with a ferric citrate-hydroxamate uptake system and to catalyze iron release efficiently from Fe[III]-dicitrate, Fe[III]-schizokinen, Fe[III]-aerobactin, and ferrichrome. The gene was hence named fchR for ferric citrate and hydroxamate reductase. The tightly bound [2Fe-2S] cofactor of FchR was identified by UV-visible, EPR, CD spectroscopy, and mass spectrometry. Iron release kinetics were determined with several substrates by using ferredoxin as electron donor. Catalytic efficiencies were strongly enhanced in the presence of an iron-sulfur scaffold protein scavenging the released ferrous iron. Competitive inhibition of FchR was observed with Ga(III)-charged siderophores with K(i) values in the micromolar range. The principal catalytic mechanism was found to couple increasing K(m) and K(D) values of substrate binding with increasing k(cat) values, resulting in high catalytic efficiencies over a wide redox range. Physiologically, a chromosomal fchR deletion led to strongly impaired growth during iron limitation even in the presence of ferric siderophores. Inductively coupled plasma-MS analysis of ΔfchR revealed intracellular iron accumulation, indicating that the ferric substrates were not efficiently metabolized. We further show that FchR can be efficiently inhibited by redox-inert siderophore mimics in vivo, suggesting that substrate-specific ferric siderophore reductases may present future targets for microbial pathogen control. PMID:21051545

  20. Effect of ionic strength on ligand exchange kinetics between a mononuclear ferric citrate complex and siderophore desferrioxamine B

    NASA Astrophysics Data System (ADS)

    Ito, Hiroaki; Fujii, Manabu; Masago, Yoshifumi; Waite, T. David; Omura, Tatsuo

    2015-04-01

    The effect of ionic strength (I) on the ligand exchange reaction between a mononuclear ferric citrate complex and the siderophore, desferrioxamine B (DFB), was examined in the NaCl concentration range of 0.01-0.5 M, particularly focusing on the kinetics and mechanism of ligand exchange under environmentally relevant conditions. Overall ligand exchange rate constants were determined by spectrophotometrically measuring the time course of ferrioxamine B formation at a water temperature of 25 °C, pH 8.0, and citrate/Fe molar ratios of 500-5000. The overall ligand exchange rate decreased by 2-11-fold (depending on the citrate/Fe molar ratios) as I increased from approximately 0.01 to 0.5 M. In particular, a relatively large decrease was observed at lower I (<0.1 M). A ligand exchange model describing the effect of I on the ligand exchange rate via disjunctive and adjunctive pathways was developed by considering the pseudo-equilibration of ferric citrate complexes and subsequent ferrioxamine formation on the basis of the Eigen-Wilkins metal-ligand complexation theory. The model and experimental data consistently suggest that the adjunctive pathway (i.e., direct association of DFB with ferric mono- and di-citrate complexes following dissociation of citrate from the parent complexes) dominates in ferrioxamine formation under the experimental conditions used. The model also predicts that the higher rate of ligand exchange at lower I is associated with the decrease in the ferric dicitrate complex stability because of the relatively high electrical repulsion between ferric monocitrate and free citrate at lower I (note that the reactivity of ferric dicitrate with DFB is smaller than that for the monocitrate complex). Overall, the findings of this study contribute to the understanding of the potential effect of I on ligand exchange kinetics in natural waters and provide fundamental knowledge on iron transformation and bioavailability.

  1. Six-coordinate ferric porphyrins containing bidentate N-t-butyl-N-nitrosohydroxylaminato ligands: structure, magnetism, IR spectroelectrochemisty, and reactivity.

    PubMed

    Xu, Nan; Christian, Jonathan H; Dalal, Naresh S; Abucayon, Erwin G; Lingafelt, Colin; Powell, Douglas R; Richter-Addo, George B

    2015-12-14

    NONOates (diazeniumdiolates) containing the [X{N2O2}](-) functional group are frequently employed as nitric oxide (NO) donors in biology, and some NONOates have been shown to bind to metalloenzymes. We report the preparation, crystal structures, detailed magnetic behavior, redox properties, and reactivities of the first isolable alkyl C-NONOate complexes of heme models, namely (OEP)Fe(?(2)-ON(t-Bu)NO) (1) and (TPP)Fe(?(2)-ON(t-Bu)NO) (2) (OEP = octaethylporphyrinato dianion, TPP = tetraphenylporphyrinato dianion). The compounds display the unusual NONOate O,O-bidentate binding mode for porphyrins, resulting in significant apical Fe displacements (+0.60 for 1, and +0.69 for 2) towards the axial ligands. Magnetic susceptibility and magnetization measurements made from 1.8-300 K at magnetic fields from 0.02 to 5 T, yielded magnetic moments of 5.976 and 5.974 Bohr magnetons for 1 and 2, respectively, clearly identifying them as high-spin (S = 5/2) ferric compounds. Variable-frequency (9.4 GHz and 34.5 GHz) EPR measurements, coupled with computer simulations, confirmed the magnetization results and yielded more precise values for the spin Hamiltonian parameters: g(avg) = 2.00 0.03, |D| = 3.89 0.09 cm(-1), and E/D = 0.07 0.01 for both compounds, where D and E are the axial and rhombic zero-field splittings. IR spectroelectrochemistry studies reveal that the first oxidations of these compounds occur at the porphyrin macrocycles and not at the Fe-NONOate moieties. Reactions of 1 and 2 with a histidine mimic (1-methylimidazole) generate RNO and NO, both of which may bind to the metal center if sterics allow, as shown by a comparative study with the Cupferron complex (T(p-OMe)PP)Fe(?(2)-ON(Ph)NO). Protonation of 1 and 2 yields N2O as a gaseous product, presumably from the initial generation of HNO that dimerizes to the observed N2O product. PMID:26530148

  2. Meta-analysis of efficacy and safety of intravenous ferric carboxymaltose (Ferinject) from clinical trial reports and published trial data

    PubMed Central

    2011-01-01

    Background Recommendations given for intravenous iron treatment are typically not supported by a high level of evidence. This meta-analysis addressed this by summarising the available date from clinical trials of ferric carboxymaltose using clinical trial reports and published reports. Methods Clinical trial reports were supplemented by electronic literature searches comparing ferric carboxymaltose with active comparators or placebo. Various outcomes were sought for efficacy (attainment of normal haemoglobin (Hb), increase of Hb by a defined amount, for example), together with measures of harm, including serious adverse events and deaths. Results Fourteen studies were identified with 2,348 randomised patients exposed to ferric carboxymaltose, 832 to oral iron, 762 to placebo, and 384 to intravenous iron sucrose. Additional data were available from cohort studies. Intravenous ferric carboxymaltose was given up to the calculated iron deficit (up to 1,000 mg in one week) for iron deficiency anaemia secondary to chronic kidney disease, blood loss in obstetric and gynaecological conditions, gastrointestinal disease, and other conditions like heart failure. The most common comparator was oral iron, and trials lasted 1 to 24 weeks. Intravenous ferric carboxymaltose improved mean Hb, serum ferritin, and transferrin saturation levels; the mean end-of-trial increase over oral iron was, for Hb 4.8 (95% confidence interval 3.3 to 6.3) g/L, for ferritin 163 (153 to 173) ?g/L, and for transferrin saturation 5.3% (3.7 to 6.8%). Ferric carboxymaltose was significantly better than comparator in achievement of target Hb increase (number needed to treat (NNT) 6.8; 5.3 to 9.7) and target Hb NNT (5.9; 4.7 to 8.1). Serious adverse events and deaths were similar in incidence in ferric carboxymaltose and comparators; rates of constipation, diarrhoea, and nausea or vomiting were lower than with oral iron. Conclusions This review examined the available trials of intravenous ferric carboxymaltose using details from published papers and unpublished clinical trial reports. It increases the evidence available to support recommendations given for intravenous iron treatment, but there are limited trial data comparing different intravenous iron preparations. PMID:21942989

  3. The Structures of Thiolate- and Carboxylate-Ligated Ferric H93G Myoglobin

    PubMed Central

    Qin, Jie; Perera, Roshan; Lovelace, Leslie L.; Dawson, John H.; Lebioda, Lukasz

    2008-01-01

    Crystal structures of the ferric H93G myoglobin (Mb) cavity mutant containing either an anionic proximal thiolate sulfur-donor or carboxylate oxygen-donor ligand are reported at 1.7 and 1.4 Å resolution, respectively. The crystal structure and magnetic circular dichroism spectra of the H93G Mb β-mercaptoethanol (BME) thiolate adduct reveal a high-spin, five-coordinate complex. Furthermore, the bound BME appears to have an intramolecular hydrogen bond involving the alcohol proton and the ligated thiolate sulfur, mimicking one of the three proximal N-H···S hydrogen bonds in cytochrome P450. The Fe is displaced from the porphyrin plane by 0.5 Å and forms a 2.41 Å Fe-S bond. The Fe3+-S-C angle is 111 °, indicative of a covalent Fe-S bond with sp3 hybridized sulfur. Therefore, the H93G Mb·BME complex provides an excellent protein-derived structural model for high-spin ferric P450. In particular, the Fe-S bond in high-spin ferric P450-CAM has essentially the same geometry despite the constraints imposed by covalent linkage of the cysteine to the protein backbone. This suggests that evolution led to the geometric optimization of the proximal Fe-S(cysteinate) bond in P450. The crystal structure and spectral properties of the H93G Mb acetate adduct reveal a high-spin, six-coordinate complex with proximal acetate and distal water axial ligands. The distal His-64 forms a hydrogen bond with the bound water. The Fe-acetate bonding geometry is inconsistent with an electron pair along the Fe-O bond as the Fe-O-C angle is 152° and the Fe is far from the plane of the acetate. Thus, the Fe-O bonding is ionic. The H93G Mb cavity mutant has already been shown to be a versatile model system for the study of ligand binding to heme proteins; this investigation affords the first structural evidence that non-imidazole exogenous ligands bind in the proximal ligation site. PMID:16519512

  4. Spin state transitions upon visible and infrared excitation of ferric MbN3

    NASA Astrophysics Data System (ADS)

    Helbing, Jan

    2012-03-01

    When azide binds to ferric Myoglobin it forms either a low-spin or a high-spin complex, which give rise to two well-separated asymmetric stretch bands of the ligand. Both electronic excitation of the Q-band and vibrational excitation of N3- in the mid-IR lead to a similar ultrafast population redistribution in favor of the high spin configuration, which is characterized by a 8 reorientation of the ligand transition dipole moment. The more stable low spin complex subsequently re-emerges with a 18 ps time-constant. It is argued that the observed spin state changes are caused by the participation of low-lying electronic excitations in the cooling process of heme.

  5. Synthesis and proton NMR studies of the electronic structure of ferric phosphine porphyrin complexes

    SciTech Connect

    Simonneaux, G.; Sodano, P.

    1988-11-02

    The preparation and spectral properties of low-spin ferric phosphine complexes of a series of synthetic and natural porphyrins have been reported. The proton NMR spectra of Fe(TPP)(PMe/sub 3/)/sub 2/ClO/sub 4/ and Fe(TPP)(PMe/sub 3/)(1-Melm)ClO/sub 4/ have been analyzed. The axial ligand hyperfine shifts have been separated into their dipolar and contact contributions by using both the dominant dipolar shifts for certain porphyrin positions and the magnetic anisotropy data derived from low-temperature ESR spectra. The contact shifts are shown to arise primarily from iron ..-->.. phosphine ..pi..* charge transfer. The trimethylphosphine H peak is shown to shift characteristically upfield on going from (Fe(TPP)PMe/sub 32/)/sup +/ to (Fe(TPP)(PMe/sub 3/)(1-MeIm))/sup +/, confirming that this resonance may serve as a new probe for hemoproteins. 25 references, 2 figures, 3 tables.

  6. 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.

  7. The Porphyromonas gingivalis ferric uptake regulator orthologue does not regulate iron homeostasis

    PubMed Central

    Butler, Catherine; Mitchell, Helen; Dashper, Stuart; Reynolds, Eric

    2015-01-01

    Porphyromonas gingivalis is a Gram-negative anaerobic bacterium that has an absolute requirement for iron which it transports from the host as heme and/or Fe2+. Iron transport must be regulated to prevent toxic effects from excess metal in the cell. P. gingivalis has one ferric uptake regulator (Fur) orthologue encoded in its genome called Har, which would be expected to regulate the transport and usage of iron within this bacterium. As a gene regulator, inactivation of Har should result in changes in gene expression of several genes compared to the wild-type. This dataset (GEO accession number GSE37099) provides information on expression levels of genes in P. gingivalis in the absence of Har. Surprisingly, these genes do not relate to iron homeostasis. PMID:26484248

  8. Treatment of antigen-induced arthritis in rabbits with dysprosium-165-ferric hydroxide macroaggregates

    SciTech Connect

    Zuckerman, J.D.; Sledge, C.B.; Shortkroff, S.; Venkatesan, P.

    1989-01-01

    Dysprosium-165-ferric hydroxide macroaggregates (/sup 165/Dy-FHMA) was used as an agent of radiation synovectomy in an antigen-induced arthritis model in New Zealand white rabbits. Animals were killed up to 6 months after treatment. /sup 165/Dy-FHMA was found to have a potent but temporary antiinflammatory effect on synovium for up to 3 months after treatment. Treated knees also showed significant preservation of articular cartilage architecture and proteoglycan content compared with untreated controls, but only during the first 3 months after treatment. In animals killed 3 and 6 months after treatment there were only minimal differences between the treated and untreated knees, indicating that the antiinflammatory effects on synovial tissue and articular cartilage preservation were not sustained.

  9. Authigenic vivianite in Potomac River sediments: control by ferric oxy-hydroxides.

    USGS Publications Warehouse

    Hearn, P.P.; Parkhurst, D.L.; Callender, E.

    1983-01-01

    Sand-size aggregates of vivianite crystals occur in the uppermost sediments of the Potomac River estuary immediately downstream from the outfall of a sewage treatment plant at the southernmost boundary of the District of Columbia, USA. They are most abundant in a small area of coarse sand (dredge spoil) which contrasts with the adjacent, much finer sediments. The sewage outfall supplies both reducing conditions and abundant phosphate. Analyses and calculations indicate that the pore waters in all the adjacent sediments are supersaturated with respect to vivianite. Its concentration in the coarse sand is attributed to the absence there of amorphous ferric oxyhydroxides, which are present in the finer sediments and preferentially absorb the phosphate ion. -H.R.B.

  10. Structure and kinetics of formation of catechol complexes of ferric soybean lipoxygenase-1

    SciTech Connect

    Nelson, M.J.; Brennan, B.A.; Chase, D.B. |

    1995-11-21

    Ferric soybean lipoxygenase forms stable complexes with 4-substituted catechols. The structure of the complex between the enzyme and 3,4-dihydroxybenzonitrile has been studied by resonance Raman, electron paramagnetic resonance, visible, and X-ray spectroscopies. It is a bidentate iron-catecholate complex with at least one water ligand. The kinetics of formation of complexes between lipoxygenase and 3,4-dihydroxybenzonitrile and 3,4-dihydroxyacetophenone have been studied by stopped-flow spectroscopy. The data are consistent with two kinetically distinct, reversible steps. The pH dependence of the first step suggests that the substrate for the reaction is the catechol monoanion. When these results are combined, plausible mechanisms for the complexation reaction are suggested. 51 refs., 12 figs., 2 tabs.

  11. Arsenic sorption onto titanium dioxide, granular ferric hydroxide and activated alumina: batch and dynamic studies.

    PubMed

    Lescano, Maia R; Passala, Claudio; Zalazar, Cristina S; Brandi, Rodolfo J

    2015-01-01

    The aim of this work was to evaluate and compare the efficiencies of three different adsorbents for arsenic (As) removal from water: titanium dioxide (TiO2), granular ferric hydroxide (GFH) and activated alumina (AA). Equilibrium experiments for dissolved arsenite and arsenate were carried out through batch tests. Freundlich and Langmuir isotherm models were adopted and their parameters were estimated by non-linear regressions. In addition, dynamic experiments were performed in mini fixed bed columns and breakthrough curves were obtained for each combination of sorbate/adsorbent. Experimental results obtained by column assays were compared with predictions of well-known breakthrough models (Bohart-Adams and Clark). Results indicate that As(V) is more easily adsorbed than As(III) for AA and GFH, while TiO2 has a similar behavior for both species. The titanium-based material is the most efficient adsorbent to carry out the process, followed by the GFH. PMID:25723069

  12. 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.

  13. Application of ferric sludge to immobilize leachable mercury in soils and concrete.

    PubMed

    Zhuang, J Ming; Walsh, T; Lam, T; Boulter, D

    2003-11-01

    A Hg-contaminated site in B.C. Province, Canada was caused by the previous operation of Hg-cell in chlor-alkali process for over 25 years. The soils and groundwater at the site are highly contaminated with mercury. An analysis of groundwater at the site has shown that most of the mercury is bonded with humic and fulvic acids (HFA) in colloidal form. The Hg-HFA colloids can be completely removed from the groundwater with ferric chloride treatment under optimized process conditions to form ferric sludge (FS), which is rendered non-leachable by standard TCLP (Toxicity Characteristic Leaching Procedure) test. The effluent discharged from a clarifier has achieved mercury levels of < 0.5 microkg l(-1). The studies of mercury adsorption characteristics of FS show it has low mercury leachability by TCLP, and great mercury adsorption capability. This feature is the basis for the application of FS to immobilization of leachable Hg-contaminants in solid wastes. Full-scale stabilization tests of Hg-contaminated soil have been carried out, and the time-based stability of the treated soil has been monitored by TCLP over a period of 60 days. All the results have shown a small variation in TCLP mercury levels within a range of 10-40 microg l(-1). Based on these results and with the approval of the B.C. Ministry of the Environment, 1850 tons of Hg-contaminated soils and 260 tons of Hg-contaminated concrete fines have been treated, stabilized with FS, and disposed in a non-hazardous waste disposal site. PMID:14733397

  14. Perturbation-response scanning reveals ligand entry-exit mechanisms of ferric binding protein.

    PubMed

    Atilgan, Canan; Atilgan, Ali Rana

    2009-10-01

    We study apo and holo forms of the bacterial ferric binding protein (FBP) which exhibits the so-called ferric transport dilemma: it uptakes iron from the host with remarkable affinity, yet releases it with ease in the cytoplasm for subsequent use. The observations fit the "conformational selection" model whereby the existence of a weakly populated, higher energy conformation that is stabilized in the presence of the ligand is proposed. We introduce a new tool that we term perturbation-response scanning (PRS) for the analysis of remote control strategies utilized. The approach relies on the systematic use of computational perturbation/response techniques based on linear response theory, by sequentially applying directed forces on single-residues along the chain and recording the resulting relative changes in the residue coordinates. We further obtain closed-form expressions for the magnitude and the directionality of the response. Using PRS, we study the ligand release mechanisms of FBP and support the findings by molecular dynamics simulations. We find that the residue-by-residue displacements between the apo and the holo forms, as determined from the X-ray structures, are faithfully reproduced by perturbations applied on the majority of the residues of the apo form. However, once the stabilizing ligand (Fe) is integrated to the system in holo FBP, perturbing only a few select residues successfully reproduces the experimental displacements. Thus, iron uptake by FBP is a favored process in the fluctuating environment of the protein, whereas iron release is controlled by mechanisms including chelation and allostery. The directional analysis that we implement in the PRS methodology implicates the latter mechanism by leading to a few distant, charged, and exposed loop residues. Upon perturbing these, irrespective of the direction of the operating forces, we find that the cap residues involved in iron release are made to operate coherently, facilitating release of the ion. PMID:19851447

  15. Thermodynamic modeling of ferric phosphate precipitation for phosphorus removal and recovery from wastewater.

    PubMed

    Zhang, Tao; Ding, Lili; Ren, Hongqiang; Guo, Zhitao; Tan, Jing

    2010-04-15

    Phosphorus removal and recovery by ferric phosphate (FePO(4) x 2 H(2)O) precipitation has been considered as an effective technology. In the present study, we examined chemical precipitation thermodynamic modeling of the PHREEQC program for phosphorus removal and recovery from wastewater. The objective of this research was to employ thermodynamic modeling to evaluate the effect of solution factors on FePO(4) x 2 H(2)O precipitation. In order to provide comparison, with the evaluation of thermodynamic modeling, the case study of phosphate removal from anaerobic supernatant was studied. The results indicated that the saturation-index (SI) of FePO(4) x 2 H(2)O followed a polynomial function of pH, and the solution pH influenced the ion activities of ferric iron salts and phosphate. The SI of FePO(4) x 2 H(2)O increased with a logarithmic function of Fe(3+):PO(4)(3-) molar ratio (Fe/P) and initial PO(4)(3-) concentration, respectively. Furthermore, the SI of FePO(4) x 2 H(2)O decreased with a logarithmic function of alkalinity and ionic strength, respectively. With an increase in temperature, the SI at pH 6.0 and 9.0 decreased with a linear function, and the SI at pH 4.0 followed a polynomial function. For the case study of phosphate removal from anaerobic supernatant, the phosphate removal trend at different pH and Fe/P was closer to the predictions of thermodynamic modeling. The results indicated that the thermodynamic modeling of FePO(4) x 2 H(2)O precipitation could be utilized to predict the technology parameters for phosphorus removal and recovery. PMID:20004518

  16. Acidibacter ferrireducens gen. nov., sp. nov.: an acidophilic ferric iron-reducing gammaproteobacterium.

    PubMed

    Falagn, Carmen; Johnson, D Barrie

    2014-11-01

    An acidophilic gammaproteobacterium, isolated from a pit lake at an abandoned metal mine in south-west Spain, was shown to be distantly related to all characterized prokaryotes, and to be the first representative of a novel genus and species. Isolate MCF85 is a Gram-negative, non-motile, rod-shaped mesophilic bacterium with a temperature growth optimum of 32-35 C (range 8-45 C). It was categorized as a moderate acidophile, growing optimally at pH 3.5-4.0 and between pH 2.5 and 4.5. Under optimum conditions its culture doubling time was around 75 min. Only organic electron donors were used by MCF85, and the isolate was confirmed to be an obligate heterotroph. It grew on a limited range of sugars (hexoses and disaccharides, though not pentoses) and some other small molecular weight organic compounds, and growth was partially or completely inhibited by small concentrations of some aliphatic acids. The acidophile grew in the presence of >100 mM ferrous iron or aluminium, but was more sensitive to some other metals, such as copper. It was also much more tolerant of arsenic (V) than arsenic (III). Isolate MCF85 catalysed the reductive dissolution of the ferric iron mineral schwertmannite when incubated under micro-aerobic or anaerobic conditions, causing the culture media pH to increase. There was no evidence, however, that the acidophile could grow by ferric iron respiration under strictly anoxic conditions. Isolate MCF85 is the designated type strain of the novel species Acidibacter ferrireducens (=DSM 27237(T) = NCCB 100460(T)). PMID:25116055

  17. Cloning and Characterization of vuuA, a Gene Encoding the Vibrio vulnificus Ferric Vulnibactin Receptor

    PubMed Central

    Webster, Athena C. D.; Litwin, Christine M.

    2000-01-01

    The ability of Vibrio vulnificus to acquire iron from the host has been shown to correlate with virulence. Many iron transport genes are regulated by iron, and in V. vulnificus, transcriptional regulation by iron depends on the fur gene. The N-terminal amino acid sequence of a 72-kDa iron-regulated outer membrane protein purified from a V. vulnificus fur mutant had 53% homology with the first 15 amino acids of the mature protein of the Vibrio cholerae vibriobactin receptor, ViuA. In this report, we describe the cloning, DNA sequence, mutagenesis, and analysis of transcriptional regulation of the structural gene for VuuA, the vulnibactin receptor of V. vulnificus. Analysis of the DNA sequence of the vuuA promoter region demonstrated a sequence identical to the upstream Fur box of V. cholerae viuA. Northern blot analysis showed that the transcript was strongly regulated by iron. The amino acid sequence of VuuA was 74% identical to the sequence of V. cholerae ViuA and was homologous to those of several TonB-dependent outer membrane receptors. An internal deletion of the V. vulnificus vuuA gene resulted in the loss of expression of the 72-kDa protein and the loss of the ability to use transferrin or vulnibactin as a source of iron. This mutant showed reduced virulence in an infant mouse model. Introduction of a plasmid containing the complete viuA coding sequence and 342 bp of upstream DNA into the mutant restored ferric vulnibactin and ferric transferrin utilization to the mutant. PMID:10639413

  18. High-nuclearity mixed-chelate ferric complexes from a new family of polynuclear precursors.

    PubMed

    Boskovic, Colette; Gdel, Hans U; Labat, Gal; Neels, Antonia; Wernsdorfer, Wolfgang; Moubaraki, Boujemaa; Murray, Keith S

    2005-05-01

    The syntheses, structures, and magnetochemical characterization of two novel mixed-chelate undeca- and dodecanuclear ferric complexes are reported. Preformed tri- and pentanuclear ferric complexes that possess tridentate Schiff base (L2- and (L'2-) and acetate ligands were reacted with 1,1,1-tris(hydroxymethyl)ethane (H3thme) to afford [Fe11O3(OH)(O2CMe)8(thme)2(L)6] (1) and [Fe12O4(O2CMe)8(thme)2(NH2(CH2)2O)2(L')6] (2), respectively, following structural agglomeration and rearrangement associated with ligand substitution. The incorporation of more than one type of ligand that can both chelate and bridge the Fe centers gives rise to the complicated molecular structures displayed by 1 and 2. As a result of the tripodal conformation of thme3-, the cores of both molecules incorporate several face-shared defect {Fe3O4}+ cuboidal subunits. Variable-temperature dc and ac magnetic susceptibility studies, together with low-temperature magnetization measurements, are consistent with S = 5/2 and S = 0 ground-state spins for 1 and 2, respectively, and suggest that excited states with higher spin values lie relatively close in energy to the ground state for both species. Low-temperature micro-SQUID measurements on oriented single crystals of 1 confirm the easy-axis type magnetic anisotropy suggested by conventional SQUID magnetometry. However magnetization hysteresis is not observed down to 0.04 K, which is ascribed to rapid quantum tunneling of the magnetization associated with transverse interactions. PMID:15847425

  19. Determination of antioxidant capacities of vegetable oils by ferric-ion spectrophotometric methods.

    PubMed

    Szydłowska-Czerniak, Aleksandra; Dianoczki, Csilla; Recseg, Katalin; Karlovits, György; Szłyk, Edward

    2008-08-15

    Two ferric-ion-based total antioxidant capacity methods: 1,10-phenanthroline (Phen) and ferric reducing antioxidant power (FRAP) were used for determination of antioxidant capacities (AC) of the acetonic and methanolic extracts of vegetable oils. The obtained mean Phen and FRAP values for acetonic extracts of olive oils, rapeseed, rice and four sunflower oils (39.3-336.5 and 39.5-339.6 micromol Fe/100g) were higher than for methanolic extracts (22.8-307.3 and 23.5-300.1 micromol Fe/100g). However, antioxidant capacities of methanolic extracts of corn oil, blended oils and two sunflower oils with garden green flowers (56.5-312.9 and 53.9-306.5 micromol Fe/100g for Phen and FRAP methods, respectively) were higher than for acetonic extracts of these oils (54.2-249.2 and 52.9-244.7 micromol Fe/100g for Phen and FRAP methods, respectively). There is a linear and significant correlation between these two analytical methods (r=0.9989 and 0.9986 for acetonic and methanolic extracts). Also, total phenolic compounds (TPC) in the studied oils correlated with their antioxidant capacities determined by Phen and FRAP methods (r=0.9012, 0.7818 and 0.8947, 0.7830 for acetonic and methanolic extracts, respectively). The comparable precision (R.S.D.=0.8-4.6%, 0.9-4.9% and 0.7-4.0%, 0.6-4.0% for acetonic and methanolic extracts, respectively) and sensitivity (epsilon=1.27 x 10(4), 1.11 x 10(4) and 2.62 x 10(4)dm(3)mol(-1)cm(-1)) for the proposed Phen and the modified FRAP methods, demonstrate the benefit of the Phen method in the routine analysis of antioxidant capacities of vegetable oils. PMID:18656676

  20. Synthesis of nanocrystalline tin oxide thin film by swift heavy ion irradiation.

    PubMed

    Mohanty, T; Satyam, P V; Kanjilal, D

    2006-08-01

    Nanocrystals of tin oxide were formed in e-beam evaporated films by swift heavy ion (SHI) irradiation. The nucleation of nanocrystals occurred due to electronic excitation by swift heavy ion. Nanophase thin films are characterized systematically by HRTEM, GAXRD, EDX, and UV/NIS absorption techniques. Nanocrystals having size of 8 nm radius are synthesized in different substrates during swift heavy ion irradiation and without subsequent annealing. SHI induced nanocrystallization could be achieved in both crystalline and non-crystalline substrates. PMID:17037871

  1. Comparative Evaluation of Aluminum Sulfate and Ferric Sulfate-Induced Coagulations as Pretreatment of Microfiltration for Treatment of Surface Water.

    PubMed

    Song, Yali; Dong, Bingzhi; Gao, Naiyun; Deng, Yang

    2015-06-01

    Two coagulants, aluminum sulfate and ferric chloride, were tested to reduce natural organic matter (NOM) as a pretreatment prior to polyvinylidene fluoride (PVDF) microfiltration (MF) membranes for potable water treatment. The results showed that the two coagulants exhibited different treatment performance in NOM removal. Molecular weight (MW) distributions of NOM in the tested surface raw water were concentrated at 3-5 kDa and approximately 0.2 kDa. Regardless of the coagulant species and dosages, the removal of 0.2 kDa NOM molecules was limited. In contrast, NOM at 3-5 kDa were readily removed with increasing coagulant dosages. In particular, aluminum sulfate favorably removed NOM near 5 kDa, whereas ferric chloride tended to reduce 3 kDa organic substances. Although aluminum sulfate and ferric chloride could improve the flux of the ensuing MF treatment, the optimal coagulant dosages to achieve effective pretreatment were different: 2-30 mg/L for aluminum sulfate and >15 mg/L for ferric chloride. The scanning electron microscope (SEM) image of the membrane-filtered coagulated raw water showed that coagulation efficiency dramatically affected membrane flux and that good coagulation properties can reduce membrane fouling. PMID:26075726

  2. Ferric Perchlorate Promoted Reaction of [60]Fullerene with N-Sulfonyl Aldimines: Synthesis and Functionalization of Fulleroxazolidines.

    PubMed

    Liu, Tong-Xin; Li, Fa-Bao; Zhou, Dian-Bing; Wang, Guan-Wu

    2015-12-18

    The rare fulleroxazolidines 2 were successfully synthesized by the facile ferric perchlorate promoted reaction of [60]fullerene with various N-sulfonyl aldimines 1. Further functionalization of fulleroxazolidines by arenes in the presence of boron trifluoride afforded 1,4-bisarylation products 4. A possible reaction mechanism for the formation of the fulleroxazolidines is proposed. PMID:26595850

  3. The FRO2 ferric reductase is required for glycine betaine's effect on chilling tolerance in Arabidopsis roots.

    PubMed

    Einset, John; Winge, Per; Bones, Atle M; Connolly, Erin L

    2008-10-01

    FRO2 (At1g01580) codes for an NADPH-dependent ferric reductase in plasma membranes of root epidermal cells with a demonstrated role in iron uptake by plants. Ferric reductase activity has been shown to be the rate-limiting step for iron uptake in strategy I plants like Arabidopsis and in rice, but it has been unclear whether FRO genes have other physiological functions. We hypothesized that FRO2 was involved in chilling stress tolerance because its expression was upregulated by treatment of plants with glycine betaine (GB), a chemical that prevents reactive oxygen species (ROS) signaling in chilling stress. This idea was confirmed by showing that the FRO2 null mutant frd1-1 failed to respond to GB in chilling assays either in relation to root growth recovery or inhibition of ROS accumulation. Measurements of ferric reductase activity in wild-type plants treated with GB before chilling showed no significant GB effect compared with controls. In addition, 35S-FRO2 transgenics with elevated mRNA levels did not have improved chilling tolerance. However, ferric reductase activity in wild-type plants or 35S-FRO2 transgenics pretreated with GB was several-fold higher after chilling compared with non-pretreated controls. These experiments identify a new physiological function for FRO2, i.e. blocking ROS accumulation during chilling. They also suggest that GB has a major effect on FRO2 activity posttranscriptionally in the cold. PMID:18513375

  4. Facile preparation of ferric giniite hollow microspheres and their enhanced Fenton-like catalytic performance under visible-light irradiation.

    PubMed

    Zhang, Xuhong; Zhang, Yu; Gao, Lin; Yu, Haitao; Wei, Yu

    2015-08-15

    Ferric giniite hollow spheres with diameters of about 1.2-1.4 ?m were successfully fabricated with a one-pot hydrothermal process. All chemicals used were low-cost compounds and environmentally benign. The obtained products were characterized by field emission scanning electron microscope (FESEM), high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), nitrogen adsorption-desorption isotherms, Fourier-transform IR spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). It was found that as-prepared ferric giniite hollow spheres exhibited much enhanced photocatalytic activity (99.5%) for the degradation of methylene blue in the presence of visible light irradiation and H2O2. Experimental results indicate that the existence of the carbonaceous shells enhances the photocatalytic activity of ferric giniite hollow spheres via the synergistic effect between carbon and ferric giniite, such as improving the adsorption, absorbing more light and exhibiting high activity to produce hydroxyl radicals through catalytic decomposition of H2O2. PMID:25910223

  5. Comparative Evaluation of Aluminum Sulfate and Ferric Sulfate-Induced Coagulations as Pretreatment of Microfiltration for Treatment of Surface Water

    PubMed Central

    Song, Yali; Dong, Bingzhi; Gao, Naiyun; Deng, Yang

    2015-01-01

    Two coagulants, aluminum sulfate and ferric chloride, were tested to reduce natural organic matter (NOM) as a pretreatment prior to polyvinylidene fluoride (PVDF) microfiltration (MF) membranes for potable water treatment. The results showed that the two coagulants exhibited different treatment performance in NOM removal. Molecular weight (MW) distributions of NOM in the tested surface raw water were concentrated at 35 kDa and approximately 0.2 kDa. Regardless of the coagulant species and dosages, the removal of 0.2 kDa NOM molecules was limited. In contrast, NOM at 35 kDa were readily removed with increasing coagulant dosages. In particular, aluminum sulfate favorably removed NOM near 5 kDa, whereas ferric chloride tended to reduce 3 kDa organic substances. Although aluminum sulfate and ferric chloride could improve the flux of the ensuing MF treatment, the optimal coagulant dosages to achieve effective pretreatment were different: 230 mg/L for aluminum sulfate and >15 mg/L for ferric chloride. The scanning electron microscope (SEM) image of the membrane-filtered coagulated raw water showed that coagulation efficiency dramatically affected membrane flux and that good coagulation properties can reduce membrane fouling. PMID:26075726

  6. Managing hyperphosphatemia in patients with chronic kidney disease on dialysis with ferric citrate: latest evidence and clinical usefulness.

    PubMed

    Yagil, Yoram; Fadem, Stephen Z; Kant, Kotagal S; Bhatt, Udayan; Sika, Mohammed; Lewis, Julia B; Negoi, Dana

    2015-09-01

    Ferric citrate is a novel phosphate binder that allows the simultaneous treatment of hyperphosphatemia and iron deficiency in patients being treated for end-stage renal disease with hemodialysis (HD). Multiple clinical trials in HD patients have uniformly and consistently demonstrated the efficacy of the drug in controlling hyperphosphatemia with a good safety profile, leading the US Food and Drug Administration in 2014 to approve its use for that indication. A concurrent beneficial effect, while using ferric citrate as a phosphate binder, is its salutary effect in HD patients with iron deficiency being treated with an erythropoietin-stimulating agent (ESA) in restoring iron that becomes available for reversing chronic kidney disease (CKD)-related anemia. Ferric citrate has also been shown in several studies to diminish the need for intravenous iron treatment and to reduce the requirement for ESA. Ferric citrate is thus a preferred phosphate binder that helps resolve CKD-related mineral bone disease and iron-deficiency anemia. PMID:26336594

  7. Managing hyperphosphatemia in patients with chronic kidney disease on dialysis with ferric citrate: latest evidence and clinical usefulness

    PubMed Central

    Fadem, Stephen Z.; Kant, Kotagal S.; Bhatt, Udayan; Sika, Mohammed; Lewis, Julia B.; Negoi, Dana

    2015-01-01

    Ferric citrate is a novel phosphate binder that allows the simultaneous treatment of hyperphosphatemia and iron deficiency in patients being treated for end-stage renal disease with hemodialysis (HD). Multiple clinical trials in HD patients have uniformly and consistently demonstrated the efficacy of the drug in controlling hyperphosphatemia with a good safety profile, leading the US Food and Drug Administration in 2014 to approve its use for that indication. A concurrent beneficial effect, while using ferric citrate as a phosphate binder, is its salutary effect in HD patients with iron deficiency being treated with an erythropoietin-stimulating agent (ESA) in restoring iron that becomes available for reversing chronic kidney disease (CKD)-related anemia. Ferric citrate has also been shown in several studies to diminish the need for intravenous iron treatment and to reduce the requirement for ESA. Ferric citrate is thus a preferred phosphate binder that helps resolve CKD-related mineral bone disease and iron-deficiency anemia. PMID:26336594

  8. Epitaxial growth of nanophase magnetite in Martian meteorite Allan Hills 84001: implications for biogenic mineralization.

    PubMed

    Bradley, J P; McSween, H Y; Harvey, R P

    1998-07-01

    Crystallographic relationships between magnetite, sulfides, and carbonate rosettes in fracture zones of the Allan Hills (ALH) 84001 Martian meteorite have been studied using analytical electron microscopy. We have focused on those magnetite grains whose growth mechanisms can be rigorously established from their crystallographic properties. Individual magnetite nanocrystals on the surfaces of carbonates are epitaxially intergrown with one another in "stacks" of single-domain crystals. Other magnetite nanocrystals are epitaxially intergrown with the surfaces of the carbonate substrates. The observed magnetite/carbonate (hkl) Miller indices orientation relationships are (1, 1,3)m ¿¿ (1, 1 ,0)c and (1, 1 ,1)m ¿¿ (0,0, 3)c with lattice mismatches of approximately 13% and approximately 11%, respectively. Epitaxy is a common mode of vapor-phase growth of refractory oxides like magnetite, as is the spiral growth about axial screw dislocations previously observed in other magnetite nanocrystals in ALH 84001. Epitaxy rules out intracellular precipitation of these magnetites by (Martian) organisms, provides further evidence of the high-temperature (> 120 degrees C) inorganic origins of magnetite in ALH 84001, and indicates that the carbonates also have been exposed to elevated temperatures. PMID:11543075

  9. The role of rare-earth dopants in nanophase zirconia catalysts for automotive emission control.

    SciTech Connect

    Loong, C.-K.; Ozawa, M.

    1999-07-16

    Rare earth (RE) modification of automotive catalysts (e.g., ZrO{sub 2}) for exhaust gas treatment results in outstanding improvement of the structural stability, catalytic functions and resistance to sintering at high temperatures. Owing to the low redox potential of nonstoichiometric CeO{sub 2}, oxygen release and intake associated with the conversion between the 3+ and 4+ oxidation states of the Ce ions in Ce-doped ZrO{sub 2} provide the oxygen storage capacity that is essentially to effective catalytic functions under dynamic air-to-fuel ratio cycling. Doping tripositive RE ions such as La and Nd in ZrO{sub 2}, on the other hand, introduces oxygen vacancies that affect the electronic and ionic conductivity. These effects, in conjunction with the nanostructure and surface reactivity of the fine powders, present a challenging problem in the development of better ZrO{sub 2}-containing three-way catalysts. We have carried out in-situ small-to-wide angle neutron diffraction at high temperatures and under controlled atmospheres to study the structural phase transitions, sintering behavior, and Ce{sup 3+} {leftrightarrow} Ce{sup 4+} redox process. We found substantial effects due to RE doping on the nature of aggregation of nanoparticles, defect formation, crystal phase transformation, and metal-support interaction in ZrO{sub 2} catalysts for automotive emission control.

  10. Shallow-water hydrothermal system and sedimentation of the ferric deposit in the Nagahama-bay, Satsuma Iwo-jima Island

    NASA Astrophysics Data System (ADS)

    Ninomiya, T.; Kiyokawa, S.; Koge, S.; Oguri, K.; Yamaguchi, K. E.; Ito, T.; Ikehara, M.

    2008-12-01

    Satsuma Iwo-jima Island, located 40km south of Kyushu, Japan, has characteristic hydrothermal activities surrounding its active volcano Iwo-dake. Along the shoreline, hydrothermal fluids discharge and they cause discoloration of the seawater. At Nagahama-bay, iron ion in carbonated spring is oxidized to iron hydroxide precipitate by mixing with the sea water and the water takes on red color(Kamada, 1964). To understand the relationships among the ferric deposits, hydrothermal ventings, and the sea tide in the bay, we conducted the following studies; (a) naked eye observation at seafloor by SCUBA diving and the measurements of temperature and sediment distributions, (b) time-series in situ observation of the sesafloor by OGURI-View system (an automatic underwater digital camera system; Oguri et al., 2006), (c) time-series observation of color changes in the surface water by automatic acquisition system modified from OGURI-View, (d) geochemical analysis of the sea water collected in spring and fall 2007 and summer 2008, (e) coring to find the components in the sediment, and (f) six months-long sediment trap to estimate total mass flux in the bay. On the seafloor, numerous hot vents were found in the eastern part of the bay at 4m in depth. Soft sediment was also formed around the vents up to 1.5m thick. Temperature of the surface sediment ranged from 30 to 55 degree Celsius; the highest temperature was observed near those vents. The time-series images taken by OGURI-View system showed that turbidness of the bottom of the sea water changed daily. The turbidity data in the bay indicated that their daily changes occurred by tidal currents and sometimes by unusual mixing induced by strong typhoon. The sediment of 83cm core sample consisted of clay-sized reddish ferric oxides, quartz, volcanic ashes, rock fragments, and very fine to fine sand. From the sediment trap experiment, total mass accumulation rate was estimated to 0.12-0.18g/cm2/day. This high rate may be one factor contributing to the thick sediment.

  11. Simultaneous X-ray and neutron diffraction Rietveld refinements of nanophase iron substituted hydroxyapatite

    NASA Astrophysics Data System (ADS)

    Kyriacou, Andreas

    The effect of Fe substitution on the crystal structure of hydroxyapatite (HAp) is studied by applying simultaneous Rietveld refinements of powder x-ray and neutron diffraction patterns. Fe is one of the trace elements replacing Ca in HAp, which is the major mineral phase in bones and teeth. The morphology and magnetic properties of the Fe-HAp system are also studied by transmission electron microscopy and magnetization measurements. Samples of Ca(5-x)Fex(PO4)3OH with 0 ≤ x ≤ 0.3 were prepared. Single phase HAp was identified in x-ray diffraction patterns (XRD) of samples with x < 0.1 inferring that the solubility limits are less than 0.1. Hematite (alpha-Fe2O3) is identified as a secondary phase for higher Fe content. The refined parameters show that Fe is incorporated in the HAp structure by replacing Ca in the two crystallographic sites with a preference at the Ca2 site. This preference explains the small effect of the Fe substitution on the lattice constants of HAp. The overall decrease of the lattice constants is explained by the ionic size difference of Ca and Fe. The increasing trend of the a-lattice constant with x in the Fe substituted samples is attributed to a lattice relaxation caused by the substitution of the 4- and 6-fold Fe at the 7- and 9-fold Ca1 and Ca2 sites. This Ca local geometry reduction is indicated by a slight increase of the Ca1-O3 and Ca2-O1 bond lengths. Above the solubility limit x = 0.05, the Fe is partitioned in and out of the HAp structure with increasing nominal Fe content x. The excess Fe is oxidized to hematite. The TEM analysis and magnetic measurements support the results of the simultaneous Rietveld refinements. The TEM images show no significant effect on the morphology and size of the HAp particles upon Fe incorporation. The particles are either spheres or short rods of dimensions 20--60 nm. Hematite particles are imaged in the samples with x exceeding the solubility limit. These particles are spheres, about 15 nm in diameter and are more resistant to electron beam damage. Magnetic measurements reveal a transition of the diamagnetic pure HAp to paramagnetic Fe substituted HAp.

  12. 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.

  13. Contribution of ferric iron to the absorption by chromophoric dissolved matter

    NASA Astrophysics Data System (ADS)

    Xiao, Y. H.; Sara-aho, T.; Vhtalo, A. V.

    2012-04-01

    Chromophoric dissolved organic matter (CDOM) is a major absorber of ultraviolet and visible radiation in surface waters. CDOM consists primarily of humic substances (HS), which can adsorb inorganic cations such as ferric iron. Often more than 99% of dissolved iron is complexed by CDOM in natural waters. Our study assessed the contribution of ferric iron to the absorption of CDOM by mixing dissolved humic substance (HS) standards with iron(III) in acidic conditions and later adjusting the pH to 8. The maximum iron-binding capacities for Suwannee River humic acid, Suwannee River fulvic acid and Pony Lake fulvic acid were 13.0, 13.5 and 7.64 ?mol iron [mg C]-1, respectively, suggesting higher iron-binding capacity for terrestrial- than microbial-derived CDOM. Iron(III) associated with HS increased the absorption coefficient by CDOM by 1.73-5.33 times (?=254-550 nm). Inorganic iron, thus, contributed up to 4/5 of the absorption by CDOM (?=550 nm). In other words, only less than 1/5 of the absorption by CDOM-iron mixture was generated by organic chromophores. The associated iron decreased spectral slope coefficients of HS. This finding indicates that changes of the spectral slope by CDOM can be solely caused by inorganic interference (e.g. iron). The increase of absorption by associated iron(III) was always spectrally similar among different HS standards. We calculated a specific absorption spectrum for iron associated with dissolved HS standards. This spectrum allows estimates for the absorption by iron associated with HS in circum neutral natural waters. For Lytynlhde spring water, iron contributed over 1/10 (ca. 0.108, ?=400 nm) to the total absorption. The contribution of iron to total absorption increased with wavelength. In typical CDOM absorption measurement, water samples are filtered for the removal of particulate constituents but no attempts are implemented for separating the organic chromophores from inorganic chromophores. Our findings show that inorganic chromophores can contribute remarkably to the absorption of filtered water. So, if inorganic chromophores cannot be separated from organic chromophores, we recommend a change in the current terminology. "Chromophoric dissolved matter, CDM" should be used instead of the earlier term "chromophoric dissolved organic matter, CDOM".

  14. Catalytic performance and deactivation of precipitated iron catalyst for selective oxidation of hydrogen sulfide to elemental sulfur in the waste gas streams from coal gasification

    SciTech Connect

    Mashapa, T.N.; Rademan, J.D.; van Vuuren, M.J.J.

    2007-09-15

    The selective oxidation of hydrogen sulfide to elemental sulfur, using a commercial, precipitated silica promoted ferric oxide based catalyst, was investigated in laboratory and pilot-plant reactors. Low levels of hydrogen sulfide (1-3 vol%) can be readily removed, but a continuous slow decrease in catalyst activity was apparent. X-ray photoelectron spectroscopy showed that the loss of activity was due to the formation of ferrous sulfate, which is known to be less active than the ferric oxide. In addition, studies using a model feed showed that the propene and HCN impurities in the plant feed stocks also act as potent catalyst poisons.

  15. Expression of Mycobacterium tuberculosis ferric uptake regulator A gene in Escherichia coli and generation of monoclonal antibodies to FurA.

    PubMed

    Gao, Xue; Wang, Li-Mei; Bai, Yin-Lan; Jiang, Hong; Li, Yuan; Shi, Chang-Hong; Zhang, Hai; Xue, Ying

    2011-08-01

    Ferric uptake regulator A of Mycobacterium tuberculosis (MTB), which belongs to the Fur superfamily, is situated immediately upstream of katG encoding catalase-peroxidase, a major virulence factor that also activates the pro-drug isoniazid. The feature and role of FurA in oxidative stress contribute to research on the pathogenesis of mycobacteria. In this study, four novel mouse monoclonal antibodies were generated using the prokaryotically expressed FurA protein as immunogen. The furA gene of M. tuberculosis H37Rv was inserted into a bacterial expression vector of pRSET-A and effectively expressed in Escherichia coli BL21(DE3). The expressed fusion protein existed as soluble form in cell lysates and was purified via Ni-NTA purification system. Using the fusion protein to immunize BALB/c mice, four monoclonal antibodies (H9H6, H9E12, H10H6, and H10H8) were produced. As shown by Western blot analysis and cell fluorescence microscopy assay, the four antibodies could recognize the FurA protein, respectively. Then we assessed the effect of iron on the expression of FurA in MTB H37Rv and we concluded that iron does not affect FurA expression. These results suggest that the antibodies against FurA may provide a powerful tool for elucidating FurA biofunctions and regulation mechanism in the pathogenesis of tuberculosis. PMID:21851232

  16. Occurrences at mineral-bacteria interface during oxidation of arsenopyrite by Thiobacillus ferrooxidans.

    PubMed

    Fernandez, M G; Mustin, C; de Donato, P; Barres, O; Marion, P; Berthelin, J

    1995-04-01

    The combination of an improved bacterial desorption method, scanning electron microscopy (SEM), diffuse reflectance and transmission infrared Fourier transform spectroscopy, and a desorption-leaching device like high-pressure liquid chromatography (HPLC) was used to analyze bacterial populations (adhering and free bacteria) and surface-oxidized phases (ferric arsenates and elemental sulfur) during the arsenopyrite biooxidation by Thiobacillus ferrooxidans. The bacterial distribution, the physicochemical composition of the leachate, the evolution of corrosion patterns, and the nature and amount of the surface-oxidized chemical species characterized different behavior for each step of arsenopyrite bioleaching. The first step is characterized by a slow but strong adhesion of bacteria to mineral surfaces, the appearance of a surface phase of elemental sulfur, the weak solubilization of Fe(II), As(III), and As(V), and the presence of the first corrosion patterns, which follow the fragility zones and the crystallographic orientation of mineral grains. After this short step, growth of the unattached bacteria begins, while ferrous ions in solution are oxidized by them. Ferric ions produced by the bacteria can oxidize the sulfide directly and are regenerated by Fe(II) bacterial oxidation. At this time, a bioleaching cycle takes place and a coarse surface phase of ferric arsenate (FeAsO(4) . xH(2)O where x approximately 2) and deep ovoid pores appear. At the end of the bioleaching cycle, the high concentration of Fe(III) and As(V) in solution promotes the precipitation of a second phase of amorphous ferric arsenate (FeAsO(4) . xH(2)O where x approximately 4) in the leachate. Then the biooxidation process ceases: The bacteria adhering to the mineral sufaces are coated by the ferric arsenates and the concentration of Fe(III) on the leachate is found to have decreased greatly. Both oxidation mechanisms (direct and indirect oxidation) have been stopped. (c) 1995 John Wiley & Sons, Inc. PMID:18623257

  17. Conduction mechanisms at low- and high-resistance states in aluminum/anodic aluminum oxide/aluminum thin film structure

    NASA Astrophysics Data System (ADS)

    Zhu, W.; Chen, T. P.; Liu, Y.; Fung, S.

    2012-09-01

    In this work, conduction mechanisms of Al/anodic Al oxide/ Al structure, which exhibits resistive switching behavior, have been investigated. The low-resistance state shows ohmic conduction with a metal-like behavior similar to that of pure aluminum. The situation can be explained by the existence of the metallic filament formed by the excess Al in the Al oxide. On the other hand, the high-resistance state (HRS) shows two distinct regimes: ohmic conduction at low fields with a semiconductor-like behavior; and a non-ohmic conduction at high fields. The ohmic conduction of HRS at low fields is attributed to the electron hopping between the states in the oxide with the activation energy of ˜0.23 eV. It is suggested that the conduction of HRS at high fields (the maximum voltage is lower than the set voltage) is due to the field-enhanced thermal excitation of the electrons trapped in the states of the metallic Al nano-phase into the conduction band of the Al oxide or the electron emission from the potential well of the metallic Al nano-phase to the conduction band.

  18. Effect of ferric chloride addition and holding time on gravity belt thickening of waste activated sludge.

    PubMed

    Kozak, Joseph; Patel, Kamlesh; Abedin, Zainul; Lordi, David; O'Connor, Catherine; Granato, Thomas; Kollias, Louis

    2011-02-01

    Phosphorus removal using ferric chloride (FeCl3) addition was demonstrated at the Egan Water Reclamation Plant. Concurrently, sludge thickening performance problems occurred in the gravity belt thickeners (GBTs). Blinding problems and polymer demand change were attributed to FeCl3 and long sludge holding times. Laboratory tests were conducted to gain insight to the GBT problems. Sludge holding time effects before polymer conditioning and thickening and prolonged contact of the solids with FeCl3 were evaluated via modified time-to-filter and blinding tests developed for this study. The tests assessed the sludge filterability under polymer and FeCl3 conditioning treatments and varying sludge holding and FeCl3 contact times. It was determined that fresh sludge was the easiest to thicken compared with sludge stored for any length of time. The FeCl3 improved thickening; however, when both the FeCl3 and polymer were used as conditioners, higher FeCl3 concentrations resulted in thickening inhibition compared with polymer alone. PMID:21449475

  19. Evaluation of formocresol, calcium hydroxide, ferric sulfate, and MTA primary molar pulpotomies

    PubMed Central

    Yildiz, Esma; Tosun, Gul

    2014-01-01

    Objective: The aim of this study is to evaluate four different pulpotomy medicaments in primary molars. Materials and Methods: A total of 147 primary molars with deep caries were treated with four different pulpotomy medicaments (FC: formocresol, FS: ferric sulfate, CH: calcium hydroxide, and MTA: mineral trioxide aggregate) in this study. The criteria for tooth selection for inclusion were no clinical and radiographic evidence of pulp pathology. During 30 months of follow-up at 6-month intervals, clinical and radiographic success and failures were recorded. The differences between the groups were statistically analyzed using the Chi-square test and Kaplan-Meier analysis. Results: At 30 months, clinical success rates were 100%, 95.2%, 96.4%, and 85% in the FC, FS, MTA, and CH groups, respectively. In radiographic analysis, the MTA group had the highest (96.4%), and the CH group had the lowest success rate (85%). There were no clinical and radiographic differences between materials (P > 0.05). Conclusions: Although there were no differences between materials, only in the CH group did three teeth require extraction due to further clinical symptoms of radiographic failures during the 30-month follow-up period. None of the failed teeth in the other groups required extraction during the 30-month follow-up period. PMID:24966776

  20. CIPK23 is involved in iron acquisition of Arabidopsis by affecting ferric chelate reductase activity.

    PubMed

    Tian, Qiuying; Zhang, Xinxin; Yang, An; Wang, Tianzuo; Zhang, Wen-Hao

    2016-05-01

    Iron deficiency is one of the major limiting factors affecting quality and production of crops in calcareous soils. Numerous signaling molecules and transcription factors have been demonstrated to play a regulatory role in adaptation of plants to iron deficiency. However, the mechanisms underlying the iron deficiency-induced physiological processes remain to be fully dissected. Here, we demonstrated that the protein kinase CIPK23 was involved in iron acquisition. Lesion of CIPK23 rendered Arabidopsis mutants hypersensitive to iron deficiency, as evidenced by stronger chlorosis in young leaves and lower iron concentration than wild-type plants under iron-deficient conditions by down-regulating ferric chelate reductase activity. We found that iron deficiency evoked an increase in cytosolic Ca(2+) concentration and the elevated Ca(2+) would bind to CBL1/CBL9, leading to activation of CIPK23. These novel findings highlight the involvement of calcium-dependent CBL-CIPK23 complexes in the regulation of iron acquisition. Moreover, mutation of CIPK23 led to changes in contents of mineral elements, suggesting that CBL-CIPK23 complexes could be as "nutritional sensors" to sense and regulate the mineral homeostasis in Arabisopsis. PMID:26993237

  1. Pilot scale evaluation on ferric floc sludge concentration with pelleting flocculation blanket process.

    PubMed

    Huang, Ting-Lin; Zhang, Gang; Guo, Ning; He, Wen-jie; Han, Hong-da; Li, Zhan-peng

    2010-01-01

    Pelleting flocculation blanket (PFB) process has been successfully applied to high turbidity suspensions for high efficient solid/liquid separation. In this paper, by using the PFB process, a dynamic experimental study was carried out on concentrating ferric flocs sludge with a scale of 1.3-5.4 m(3)/h. The pilot experiment aimed to optimize the conditioning system and determine the operational parameters. Under the raw sludge concentrations of 103-1,154 mg/L, the system could achieve ideal conditioning effect with polyacrylamide (PAM) dosages of 0.3-2.7 mg/L, agitation speed of 10 rpm, and water up-flow rates of 18-48 m/h. Under the experimental conditions, the increase of polymer dosage would improve effluent turbidity and pellets settling behaviour, the moderate up-flow rate had no marked effect on treatment results, while too large surface loading could worsen effluent turbidity. The experimental results also revealed that there existed an approximately linear relationship between the raw sludge concentration and optimum PAM dosage, that is, the optimum dosage of PAM increased synchronously as the raw sludge concentration increased. While the relationship between the raw sludge concentration and maximum up-flow rate reflected another linear dependence, namely, the maximum up-flow rate would decreased linearly as the raw sludge concentration increased. PMID:21045327

  2. Stage-1 intercalation compounds of few graphene layers by anhydrous ferric chloride

    NASA Astrophysics Data System (ADS)

    Tan, Pingheng; Zhao, Weijie; Liu, Jian; Ferrari, Andrea

    2012-02-01

    Anhydrous ferric chloride (FeCl3) was used to intercalate few graphene layers into stage-1 intercalation compounds. The intercalant, staging, stability, and doping of the resulting intercalation compounds are characterized by Raman scattering. The G peak of pure stage-1 compounds upshifts to ˜1626 cm-1, which is similar to that of heavily-doped monolayer graphenes by 18M sulfuric acid. A single Lorentzian line shape for the 2D band of stage-1 compounds were observed, which indicates that each layer behaves as a decoupled heavily doped monolayer. By performing Raman measurements at different excitation energies, we show that, for a given doping level, the variation of the 2D intensity relative to the G peak with excitation energy allows one to assess the Fermi energy. This allows us to estimate a Fermi level shift of up to ˜0.85 eV, which agrees well with that estimated from the 2D/G intensity ratio and is close to ˜0.9 eV measured in stage-1 GICs by electron energy loss spectroscopy. The stage-1 intercalation compound of few graphene layers is thus ideal test-beds for the physical and chemical properties of heavily doped graphenes.

  3. Analysis of a ferric uptake regulator (Fur) knockout mutant in Aeromonas salmonicida subsp. salmonicida.

    PubMed

    Ebanks, Roger O; Goguen, Michel; Knickle, Leah; Dacanay, Andrew; Leslie, Andrew; Ross, Neil W; Pinto, Devanand M

    2013-03-23

    Aeromonas salmonicida subsp. salmonicida is the etiological agent of furunculosis; a serious infectious disease in aquaculture raised salmonids. Iron acquisition has been shown to be critical for the survival of pathogenic bacteria during the course of infection. Previous work has demonstrated that A. salmonicida expresses iron-repressible IROMP proteins, suggesting the presence of iron acquisition systems that are under the control of a ferric uptake regulator (Fur). In this study, the A. salmonicida fur has been sequenced and a fur deletion strain generated. The A. salmonicida fur gene has an open reading frame of 428 bp, coding for a protein of 143 amino acids, and with high homology to previously described Fur proteins. The Fur protein product had a 94% sequence identity and 96% sequence similarity to the Aeromonas hydrophila Fur protein product. Transcription of the A. salmonicida fur gene was not regulated by the iron status of the bacterium and is not autoregulated, as in Escherichia coli. Proteomic analysis of the A. salmonicida fur mutant, fails to repress iron-regulated outer membrane proteins in the presence of iron. The A. salmonicida fur::KO mutant shows significantly reduced pathogenicity compared to the wild-type parental strain. In addition, the A. salmonicida fur mutant provides an important tool for further investigation of the iron acquisition mechanisms utilized by A. salmonicida. PMID:23228622

  4. 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.

  5. Glutathione-dependent extracellular ferric reductase activities in dimorphic zoopathogenic fungi

    PubMed Central

    Zarnowski, Robert; Woods, Jon P.

    2009-01-01

    In this study, extracellular glutathione-dependent ferric reductase (GSH-FeR) activities in different dimorphic zoopathogenic fungal species were characterized. Supernatants from Blastomyces dermatitidis, Histoplasma capsulatum, Paracoccidioides brasiliensis and Sporothrix schenckii strains grown in their yeast form were able to reduce iron enzymically with glutathione as a cofactor. Some variations in the level of reduction were noted amongst the strains. This activity was stable in acidic, neutral and slightly alkaline environments and was inhibited when trivalent aluminium and gallium ions were present. Using zymography, single bands of GSH-FeRs with apparent molecular masses varying from 430 to 460 kDa were identified in all strains. The same molecular mass range was determined by size exclusion chromatography. These data demonstrate that dimorphic zoopathogenic fungi produce and secrete a family of similar GSH-FeRs that may be involved in the acquisition and utilization of iron. Siderophore production by these and other fungi has sometimes been considered to provide a full explanation of iron acquisition in these organisms. Our work reveals an additional common mechanism that may be biologically and pathogenically important. Furthermore, while some characteristics of these enzymes such as extracellular location, cofactor utilization and large size are not individually unique, when considered together and shared across a range of fungi, they represent an important novel physiological feature. PMID:16000713

  6. Mechanistic insights into metal ion activation and operator recognition by the ferric uptake regulator

    NASA Astrophysics Data System (ADS)

    Deng, Zengqin; Wang, Qing; Liu, Zhao; Zhang, Manfeng; Machado, Ana Carolina Dantas; Chiu, Tsu-Pei; Feng, Chong; Zhang, Qi; Yu, Lin; Qi, Lei; Zheng, Jiangge; Wang, Xu; Huo, Xinmei; Qi, Xiaoxuan; Li, Xiaorong; Wu, Wei; Rohs, Remo; Li, Ying; Chen, Zhongzhou

    2015-07-01

    Ferric uptake regulator (Fur) plays a key role in the iron homeostasis of prokaryotes, such as bacterial pathogens, but the molecular mechanisms and structural basis of Fur-DNA binding remain incompletely understood. Here, we report high-resolution structures of Magnetospirillum gryphiswaldense MSR-1 Fur in four different states: apo-Fur, holo-Fur, the Fur-feoAB1 operator complex and the Fur-Pseudomonas aeruginosa Fur box complex. Apo-Fur is a transition metal ion-independent dimer whose binding induces profound conformational changes and confers DNA-binding ability. Structural characterization, mutagenesis, biochemistry and in vivo data reveal that Fur recognizes DNA by using a combination of base readout through direct contacts in the major groove and shape readout through recognition of the minor-groove electrostatic potential by lysine. The resulting conformational plasticity enables Fur binding to diverse substrates. Our results provide insights into metal ion activation and substrate recognition by Fur that suggest pathways to engineer magnetotactic bacteria and antipathogenic drugs.

  7. Resolving the multifaceted mechanisms of the ferric chloride thrombosis model using an interdisciplinary microfluidic approach.

    PubMed

    Ciciliano, Jordan C; Sakurai, Yumiko; Myers, David R; Fay, Meredith E; Hechler, Beatrice; Meeks, Shannon; Li, Renhao; Dixon, J Brandon; Lyon, L Andrew; Gachet, Christian; Lam, Wilbur A

    2015-08-01

    The mechanism of action of the widely used in vivo ferric chloride (FeCl3) thrombosis model remains poorly understood; although endothelial cell denudation is historically cited, a recent study refutes this and implicates a role for erythrocytes. Given the complexity of the in vivo environment, an in vitro reductionist approach is required to systematically isolate and analyze the biochemical, mass transfer, and biological phenomena that govern the system. To this end, we designed an "endothelial-ized" microfluidic device to introduce controlled FeCl3 concentrations to the molecular and cellular components of blood and vasculature. FeCl3 induces aggregation of all plasma proteins and blood cells, independent of endothelial cells, by colloidal chemistry principles: initial aggregation is due to binding of negatively charged blood components to positively charged iron, independent of biological receptor/ligand interactions. Full occlusion of the microchannel proceeds by conventional pathways, and can be attenuated by antithrombotic agents and loss-of-function proteins (as in IL4-R/Iba mice). As elevated FeCl3 concentrations overcome protective effects, the overlap between charge-based aggregation and clotting is a function of mass transfer. Our physiologically relevant in vitro system allows us to discern the multifaceted mechanism of FeCl3-induced thrombosis, thereby reconciling literature findings and cautioning researchers in using the FeCl3 model. PMID:25931587

  8. Acute renal failure and glucosuria induced by ferric nitrilotriacetate in rats.

    PubMed

    Hamazaki, S; Okada, S; Ebina, Y; Midorikawa, O

    1985-02-01

    Nitrilotriacetate (NTA), an effective metal-chelating agent, has been used as a substitute for polyphosphates in household laundry detergents. Nephrotoxicity and renal tumorigenicity have been reported in experimental animals that received high doses of NTA po for 4 weeks to 2 years. Since NTA exists in water as a variety of NTA-metal complexes, it was important to investigate the biological effects of NTA in a complexed form. In this study, acute and subchronic toxicity of a ferric iron chelate of NTA (Fe-NTA) was investigated in rats. When Fe-NTA was given ip, acute tubular necrosis and renal failure occurred following a single injection of 15 mg iron/kg. Repeated injections of sublethal doses produced degeneration and necrosis of the proximal tubular epithelium and was associated with polyuria, glucosuria, aminoaciduria, and azotemia. After 9 days of treatment, regeneration of the tubular epithelium with atypical cells was observed. Except for a parenchymal iron deposit, no marked changes were observed in other organs. None of these effects were observed in animals given noncomplexed NTA. In conclusion, the toxicity observed following high doses of NTA given po may be the result of an absorbed metal-NTA chelate. PMID:3975899

  9. Overproduction in Escherichia coli and Characterization of a Soybean Ferric Leghemoglobin Reductase.

    PubMed Central

    Ji, L.; Becana, M.; Sarath, G.; Shearman, L.; Klucas, R. V.

    1994-01-01

    We previously cloned and sequenced a cDNA encoding soybean ferric leghemoglobin reductase (FLbR), an enzyme postulated to play an important role in maintaining leghemoglobin in a functional ferrous state in nitrogen-fixing root nodules. This cDNA was sub-cloned into an expression plasmid, pTrcHis C, and overexpressed in Escherichia coli. The recombinant FLbR protein, which was purified by two steps of column chromatography, was catalytically active and fully functional. The recombinant FLbR cross-reacted with antisera raised against native FLbR purified from soybean root nodules. The recombinant FLbR, the native FLbR purified from soybean (Glycine max L.) root nodules, and dihydrolipoamide dehydrogenases from pig heart and yeast had similar but not identical ultraviolet-visible absorption and fluorescence spectra, cofactor binding, and kinetic properties. FLbR shared common structural features in the active site and prosthetic group binding sites with other pyridine nucleotide-disulfide oxidoreductases such as dihydrolipoamide dehydrogenases, but displayed different microenvironments for the prosthetic groups. PMID:12232320

  10. Granular ferric hydroxide adsorbent for phosphate removal: demonstration preparation and field study.

    PubMed

    Zhao, Bei; Zhang, Yu; Dou, Xiaomin; Yuan, Hongying; Yang, Min

    2015-01-01

    Ferric hydroxide (FHO), which has high phosphate adsorption capacity, was prepared by precipitation at industrial scale and then fabricated via the drum granulation method with cross-linked poly(vinyl alcohol) as the binder. The optimum binder/FHO powder ratio was 0.6 for producing a granular adsorbent with a high phosphate adsorption capacity and stability. The Langmuir maximum adsorption capacities of powder and granular FHOs were 74.07 mg g? and 56.18 mg g(-1) at pH 7.0 0.2, respectively, which were higher than those of other reported phosphate adsorbents under neutral or acidic conditions. Phosphate-loaded granular FHO could be regenerated by NaOH solution. Columns containing the granular FHO were used for phosphate removal from ozonated secondary effluents of a municipal wastewater treatment plant at space velocity (SV) of 2 and 5 h?. During more than 2 months' operation, the average removal percentage of PO(4)(3-) was more than 90% and the turbidity and concentration of CODMn in the effluents were lower than in the influents. In addition, energy dispersive X-ray results suggested that active sites inside the granular FHO were available for phosphate removal. The results demonstrated that granular FHO can be applied as an assist technology for phosphate removal from secondary effluents. PMID:26676005

  11. Adsorption of phosphonate antiscalant from reverse osmosis membrane concentrate onto granular ferric hydroxide.

    PubMed

    Boels, Luciaan; Keesman, Karel J; Witkamp, Geert-Jan

    2012-09-01

    Adsorptive removal of antiscalants offers a promising way to improve current reverse osmosis (RO) concentrate treatment processes and enables the reuse of the antiscalant in the RO desalination process. This work investigates the adsorption and desorption of the phosphonate antiscalant nitrilotris(methylenephosphonic acid) (NTMP) from RO membrane concentrate onto granular ferric hydroxide (GFH), a material that consists predominantly of akaganite. The kinetics of the adsorption of NTMP onto GFH was predicted fairly well with two models that consider either combined film-pore or combined film-surface diffusion as the main mechanism for mass transport. It is also demonstrated that NTMP is preferentially adsorbed over sulfate by GFH at pH 7.85. The presence of calcium causes a transformation in the equilibrium adsorption isotherm from a Langmuir type to a Freundlich type with much higher adsorption capacities. Furthermore, calcium also increases the rate of adsorption substantially. GFH is reusable after regeneration with sodium hydroxide solution, indicating that NTMP can be potentially recovered from the RO concentrate. This work shows that GFH is a promising adsorbent for the removal and recovery of NTMP antiscalant from RO membrane concentrates. PMID:22873428

  12. Ferric Chloride-induced Thrombosis Mouse Model on Carotid Artery and Mesentery Vessel.

    PubMed

    Bonnard, Thomas; Hagemeyer, Christoph E

    2015-01-01

    Severe thrombosis and its ischemic consequences such as myocardial infarction, pulmonary embolism and stroke are major worldwide health issues. The ferric chloride injury is now a well-established technique to rapidly and accurately induce the formation of thrombi in exposed veins or artery of small and large diameter. This model has played a key role in the study of the pathophysiology of thrombosis, in the discovery and validation of novel antithrombotic drugs and in the understanding of the mechanism of action of these new agents. Here, the implementation of this technique on a mesenteric vessel and carotid artery in mice is presented. The method describes how to label circulating leukocytes and platelets with a fluorescent dye and to observe, by intravital microscopy on the exposed mesentery, their accumulation at the injured vessel wall which leads to the formation of a thrombus. On the carotid artery, the occlusion caused by the clot formation is measured by monitoring the blood flow with a Doppler probe. PMID:26167713

  13. Passive immunization by recombinant ferric enterobactin protein (FepA) from Escherichia coli O157

    PubMed Central

    Larrie-Bagha, Seyed Mehdi; Rasooli, Iraj; Mousavi-Gargari, Seyed Latif; Rasooli, Zohreh; Nazarian, Shahram

    2013-01-01

    Background and Objectives Enterohemorrhagic Escherichia coli (EHEC) O157:H7 has been recognized as a major food borne pathogen responsible for frequent hemorrhagic colitis and hemolytic uremic syndrome in humans. Cattle are important reservoirs of E. coli O157:H7, in which the organism colonizes the intestinal tract and is shed in the feces. Objective Vaccination of cattle has significant potential as a pre-harvest intervention strategy for E. coli O157:H7. The aim of this study was to evaluate active and passive immunization against E. coli O157:H7 using a recombinant protein. Materials and Methods The recombinant FepA protein induced by IPTG was purified by nickel affinity chromatography. Antibody titre was determined by ELISA in FepA immunized rabbits sera. Sera collected from vaccinated animals were used for bacterial challenge in passive immunization studies. Results The results demonstrate that passive immunization with serum raised against FepA protects rabbits from subsequent infection. Conclusion Significant recognition by the antibody of ferric enterobactin binding protein may lead to its application in the restriction of Enterobacteriaceae propagation. PMID:23825727

  14. Investigations of the Low Frequency Modes of Ferric Cytochrome c Using Vibrational Coherence Spectroscopy

    PubMed Central

    2015-01-01

    Femtosecond vibrational coherence spectroscopy is used to investigate the low frequency vibrational dynamics of the electron transfer heme protein, cytochrome c (cyt c). The vibrational coherence spectra of ferric cyt c have been measured as a function of excitation wavelength within the Soret band. Vibrational coherence spectra obtained with excitation between 412 and 421 nm display a strong mode at ?44 cm1 that has been assigned to have a significant contribution from heme ruffling motion in the electronic ground state. This assignment is based partially on the presence of a large heme ruffling distortion in the normal coordinate structural decomposition (NSD) analysis of the X-ray crystal structures. When the excitation wavelength is moved into the ?421435 nm region, the transient absorption increases along with the relative intensity of two modes near ?55 and 30 cm1. The intensity of the mode near 44 cm1 appears to minimize in this region and then recover (but with an opposite phase compared to the blue excitation) when the laser is tuned to 443 nm. These observations are consistent with the superposition of both ground and excited state coherence in the 421435 nm region due to the excitation of a weak porphyrin-to-iron charge transfer (CT) state, which has a lifetime long enough to observe vibrational coherence. The mode near 55 cm1 is suggested to arise from ruffling in a transient CT state that has a less ruffled heme due to its iron d6 configuration. PMID:24823442

  15. Preparation and Thermal Analysis of Ferric Doped PVA-PVP-PPy Composite Films

    NASA Astrophysics Data System (ADS)

    Patil, Ravikumar V.; Ranganath, M. R.; Lobo, Blaise

    2011-12-01

    The preparation and thermal analysis of flexible blend films of pyrrole (Py) polymerized in aqueous solution of poly (vinyl alcohol) (PVA) and poly (vinyl pyrrolidone) (PVP) is described. In-situ polymerization of pyrrole in aqueous solution of PVA and PVP containing ferric chloride (FeCl3) was achieved through vapor sorption, and the films obtained were studied using Differential Scanning Calorimetry (DSC), Thermo-Gravimetric Analysis (TGA) and Differential Thermal Analysis (DTA). No melting endotherm is seen in the DSC and DTA scans of the composite films, indicating that the sample is amorphous. Degradation of the sample is found to occur at lower temperatures, with increase in doping level (wt% of FeCl3). DSC study was performed between 40 °C and 400 °C. Below 1.2 wt % DL, degradation of the sample occurs in two stages, the first at 310 °C and the second at 440 °C, as seen from DTA and TGA scans. The broad endotherm between 80 °C and 120 °C is due to volatization of moisture (water) absorbed by the sample. Multiple endotherms are observed in DSC and DTA scans of the composite films, for FeCl3 doping levels above 3.8 wt %, and the sample degrades in many different stages at lower temperature, with increase in doping level, as revealed by weight losses in the TGA curve.

  16. Spectrophotometric techniques to determine tranexamic acid: Kinetic studies using ninhydrin and direct measuring using ferric chloride

    NASA Astrophysics Data System (ADS)

    Arayne, M. Saeed; Sultana, Najma; Siddiqui, Farhan Ahmed; Mirza, Agha Zeeshan; Zuberi, M. Hashim

    2008-11-01

    Two simple and sensitive spectrophotometric methods in ultraviolet and visible region are described for the determination of tranexamic acid in pure form and pharmaceutical preparations. The first method is based on the reaction of the drug with ninhydrin at boiling temperature and by measuring the increase in absorbance at 575 nm as a function of time. The initial rate, rate constant and fixed time (120 min) procedures were used for constructing the calibration graphs to determine the concentration of the drug, which showed a linear response over the concentration range 16-37 ?g mL -1 with correlation coefficient " r" 0.9997, 0.996, 0.9999, LOQ 6.968, 7.138, 2.462 ?gmL -1 and LOD 2.090, 2.141 and 0.739 ?gmL -1, respectively. In second method tranexamic acid was reacted with ferric chloride solution, yellowish orange colored chromogen showed ? max at 375 nm showing linearity in the concentration range of 50-800 ?g mL -1 with correlation coefficient " r" 0.9997, LOQ 6.227 ?gmL -1 and LOD 1.868 ?gmL -1. The variables affecting the development of the color were optimized and the developed methods were validated statistically and through recovery studies. These results were also verified by IR and NMR spectroscopy. The proposed methods have been successfully applied to the determination of tranexamic acid in commercial pharmaceutical formulation.

  17. Real-time monitoring of arsenic filtration by granular ferric hydroxide.

    PubMed

    Fleming, David E B; Eddy, Isadel S; Gherase, Mihai R; Gibbons, Meaghan K; Gagnon, Graham A

    2010-01-01

    Contamination of drinking water by arsenic is a serious public health issue in many parts of the world. One recent approach to this problem has been to filter out arsenic by use of granular ferric hydroxide (GFH), an adsorbent developed specifically for the selective removal of arsenic from water. Previous studies have documented the efficiency and high treatment capacity of this approach. We present a novel X-ray fluorescence method to monitor the accumulation of arsenic within a specially designed GFH column, as both a function of time (or water volume) and location along the column. Using a miniature X-ray tube and silicon PiN diode detector, X-ray fluorescence is used to detect characteristic X-rays of arsenic excited from within the GFH. Trials were performed using a water flow rate of approximately 1.5 L per hour, with an added arsenic concentration of approximately 1000 microg per litre. In this paper, trial results are presented and potential applications described. PMID:19850486

  18. Mechanistic insights into metal ion activation and operator recognition by the ferric uptake regulator

    PubMed Central

    Deng, Zengqin; Wang, Qing; Liu, Zhao; Zhang, Manfeng; Machado, Ana Carolina Dantas; Chiu, Tsu-Pei; Feng, Chong; Zhang, Qi; Yu, Lin; Qi, Lei; Zheng, Jiangge; Wang, Xu; Huo, XinMei; Qi, Xiaoxuan; Li, Xiaorong; Wu, Wei; Rohs, Remo; Li, Ying; Chen, Zhongzhou

    2015-01-01

    Ferric uptake regulator (Fur) plays a key role in the iron homeostasis of prokaryotes, such as bacterial pathogens, but the molecular mechanisms and structural basis of Fur–DNA binding remain incompletely understood. Here, we report high-resolution structures of Magnetospirillum gryphiswaldense MSR-1 Fur in four different states: apo-Fur, holo-Fur, the Fur–feoAB1 operator complex and the Fur–Pseudomonas aeruginosa Fur box complex. Apo-Fur is a transition metal ion-independent dimer whose binding induces profound conformational changes and confers DNA-binding ability. Structural characterization, mutagenesis, biochemistry and in vivo data reveal that Fur recognizes DNA by using a combination of base readout through direct contacts in the major groove and shape readout through recognition of the minor-groove electrostatic potential by lysine. The resulting conformational plasticity enables Fur binding to diverse substrates. Our results provide insights into metal ion activation and substrate recognition by Fur that suggest pathways to engineer magnetotactic bacteria and antipathogenic drugs. PMID:26134419

  19. NMR reveals pathway for ferric mineral precursors to the central cavity of ferritin

    PubMed Central

    Turano, Paola; Lalli, Daniela; Felli, Isabella C.; Theil, Elizabeth C.; Bertini, Ivano

    2010-01-01

    Ferritin is a multimeric nanocage protein that directs the reversible biomineralization of iron. At the catalytic ferroxidase site two iron(II) ions react with dioxygen to form diferric species. In order to study the pathway of iron(III) from the ferroxidase site to the central cavity a new NMR strategy was developed to manage the investigation of a system composed of 24 monomers of 20kDa each. The strategy is based on 13C-13C solution NOESY experiments combined with solid-state proton-driven 13C-13C spin diffusion and 3D coherence transfer experiments. In this way, 75% of amino acids were recognized and 35% sequence-specific assigned. Paramagnetic broadening, induced by iron(III) species in solution 13C-13C NOESY spectra, localized the iron within each subunit and traced the progression to the central cavity. Eight iron ions fill the 20-?-long iron channel from the ferrous/dioxygen oxidoreductase site to the exit into the cavity, inside the four-helix bundle of each subunit, contrasting with short paths in models. Magnetic susceptibility data support the formation of ferric multimers in the iron channels. Multiple iron channel exits are near enough to facilitate high concentration of iron that can mineralize in the ferritin cavity, illustrating advantages of the multisubunit cage structure. PMID:20018746

  20. Time-dependence of ferric reducing antioxidant power (FRAP) index in Chilean apples and berries.

    PubMed

    Henrquez, Carolina; Lpez-Alarcn, Camilo; Gmez, Maritza; Lutz, Mariane; Speisky, Hernn

    2011-09-01

    We hypothesize that the Ferric Reducing Antioxidant Power (FRAP) assay that follows the reaction of Fe(3+)-TPTZ at 593 nm underestimates the antioxidant capacity of fruits, since the standardized time of the reaction (4 min) is not enough to titrate all the reducing compounds available. We measured FRAP, total phenolics and anthocyanins content in a variety of Chilean berry fruits (blueberries, blackberries, raspberries and strawberries) and apples (cv. Fuji, Granny Smith, Pink Lady, Red Delicious and Royal Gala). Taking into account the dependence of FRAP on the time course of the reaction, we propose to measure FRAP indexes after 1 min (FRAP-1), 30 min (FRAP-30) and 120 min (FRAP-120) of incubation. Most fruit extracts showed significant correlations between the antioxidant capacity and the incubation time, although in some cases the FRAP indexes did not correlate with the total phenolics and/or anthocyanins content. In fact, in apples and berries the correlation between anthocyanins content and FRAP indexes decreased with the incubation time. It is concluded that the fruit extracts analyzed require an incubation period higher than the established in the original experimental protocol to reach the equilibrium, due to the presence of a complex mixture of antioxidant compounds. In addition, a kinetic profile should be realized in each sample studied to establish the most suitable incubation period to titrate all the reactive antioxidant species. PMID:22696902

  1. Permeability properties of a large gated channel within the ferric enterobactin receptor, FepA.

    PubMed Central

    Liu, J; Rutz, J M; Feix, J B; Klebba, P E

    1993-01-01

    FepA is an Escherichia coli outer membrane receptor protein for the siderophore ferric enterobactin. Prior studies conducted in vivo suggested that FepA and other TonB-dependent outer membrane proteins transport ligands by a gated-channel mechanism. To corroborate and extend these findings we have determined the permeability properties of the FepA channel in vitro, by measuring the diffusion rates of hydrophilic nonelectrolytes through the FepA channel in liposome swelling experiments. Like porins, the FepA deletion mutant delta RV showed a size-dependent permeability to oligosaccharides, indicating that it forms a nonspecific, hydrophilic pore. Unlike OmpF and other E. coli porins, however, delta RV proteoliposomes transported stachyose (666 Da) and ferrichrome (740 Da). These data, and other uptake results with a series of maltodextrins of increasing size, confirm the existence of a channel domain within FepA that is considerably larger than OmpF-type pores. These results represent a reconstitution of the channel function of a TonB-dependent receptor protein and establish that FepA contains the largest channel that has been characterized in the E. coli outer membrane. Images Fig. 1 PMID:7504275

  2. Comparison of the Hemostatic Activity of Quercus persica Jaub. & Spach. (Oak) With Ferric Sulfate in Bony Crypts.

    PubMed

    Nabavizadeh, Mohammad Reza; Zargaran, Arman; Moazami, Fariborz; Askari, Fatemeh; Sahebi, Safoora; Farhadpoor, Alireza; Faridi, Pouya

    2016-01-01

    Effective tissue hemostasis in periapical surgical site is important in the procedures. Plants with large amount of tannins may act as a local hemostatic agent. We aimed to compare the hemostatic effect of the extract of Quercus persica with one of the common hemostatic material used in periapical surgery. Six standardized bone holes were prepared in the calvaria of 5 Burgundy rabbits. Two hemostatic medicaments were tested for their hemostatic effect and were compared with control defects: Group 1, cotton pellet soaked in 15.5% ferric sulfate solution; Group 2, cotton pellet soaked in pure ethanolic extract of Q. persica. Bleeding score between the groups was compared. The ferric sulfate group exhibited significantly less bleeding than the other 2 groups. Q. persica was found to cause more hemostasis than the control group at 4 and 5 minutes but there were no significant differences between normal saline and Q. persica extract in bleeding control. PMID:26130010

  3. The Enzyme-mimic Activity of Ferric Nano-Core Residing in Ferritin and Its Biosensing Applications

    SciTech Connect

    Tang, Zhiwen; Wu, Hong J.; Zhang, Youyu; Li, Zhaohui; Lin, Yuehe

    2011-11-15

    Ferritins are nano-scale globular protein cages encapsulating a ferric core. They widely exist in animals, plants, and microbes, playing indispensable roles in iron homeostasis. Interestingly, our study clearly demonstrates that ferritin has an enzyme-mimic activity derived from its ferric nano-core, but not the protein cage. Further study revealed that the mimic-enzyme activity of ferritin is more thermally stable and pH-tolerant compared with horseradish peroxidase. Considering the abundance of ferritin in numerous organisms, this finding may indicate a new role of ferritin in antioxidant and detoxification metabolisms. In addition, as a natural protein-caged nanoparticle with an enzyme-mimic activity, ferritin is readily conjugated with biomolecules to construct nano-biosensors, thus holds promising potential for facile and biocompatible labeling for sensitive and robust bioassays in biomedical applications.

  4. Supplementation with a dietary multicomponent (Lafergin) based on Ferric Sodium EDTA (Ferrazone): results of an observational study

    PubMed Central

    Cignini, Pietro; Mangiafico, Lucia; Padula, Francesco; DEmidio, Laura; Dugo, Nella; Aloisi, Alessia; Giorlandino, Claudio; Vitale, Salvatore Giovanni

    2015-01-01

    During pregnancy, iron deficiency anemia is recognized as a specific risk factor for both adverse maternal and perinatal outcome. We decided to test the hypothesis that the daily administration of Lafergin, a dietary multicomponent based on Ferrazone (Ferric Sodium EDTA), Lactoferrin, Vitamin C and Vitamin B12, from first trimester of pregnancy until the end of gestation, may significantly reduce, in anemic women, the severity of anemia compared to controls who received ferrous sulfate or liposomal iron.

  5. Relative Humidity-induced Production of Ferricopiapite and Rhomboclase from Ferric Sulfate Anhydrate: X-Ray Diffraction Studies Under Controlled Conditions

    NASA Astrophysics Data System (ADS)

    Xu, W.; Tosca, N. J.; McLennan, S. M.; Parise, J. B.

    2008-03-01

    Hydration of anhydrous ferric sulfate results in complex phase transtions, including ferricopiapite and rhomboclase which are stable under very acid conditions. The process may have been important in generating acidity at the martian surface.

  6. Conversion of dissolved phosphorus in runoff by ferric sulfate to a form less available to algae: Field performance and cost assessment.

    PubMed

    Uusitalo, Risto; Närvänen, Aaro; Kaseva, Antti; Launto-Tiuttu, Aino; Heikkinen, Janne; Joki-Heiskala, Päivi; Rasa, Kimmo; Salo, Tapio

    2015-03-01

    Conversion of dissolved P by ferric sulfate into a particulate form sparingly available to algae was studied in 15 ditches in Finland using stand-alone dispensers for ferric sulfate administration. Ferric sulfate typically converted 60-70 % of dissolved P into iron-associated form, a process which required 250-650 kg per kg dissolved P. Mean cost was 160 EUR per kg P converted (range 20-400 EUR kg(-1)). The costs were lowest at sites characterized by high dissolved P concentrations and small catchment area. At best, the treatment was efficient and cost-effective, but to limit the costs and the risks, ferric sulfate dispensers should only be installed in small critical source areas. PMID:25681985

  7. Ferric Maltol Is Effective in Correcting Iron Deficiency Anemia in Patients with Inflammatory Bowel Disease: Results from a Phase-3 Clinical Trial Program

    PubMed Central

    Ahmad, Tariq; Tulassay, Zsolt; Baumgart, Daniel C.; Bokemeyer, Bernd; Bning, Carsten; Howaldt, Stefanie; Stallmach, Andreas

    2014-01-01

    Background: Iron deficiency anemia (IDA) is frequently seen in inflammatory bowel disease. Traditionally, oral iron supplementation is linked to extensive gastrointestinal side effects and possible disease exacerbation. This multicenter phase-3 study tested the efficacy and safety of ferric maltol, a complex of ferric (Fe3+) iron with maltol (3-hydroxy-2-methyl-4-pyrone), as a novel oral iron therapy for IDA. Methods: Adult patients with quiescent or mild-to-moderate ulcerative colitis or Crohn's disease, mild-to-moderate IDA (9.512.0 g/dL and 9.513.0 g/dL in females and males, respectively), and documented failure on previous oral ferrous products received oral ferric maltol capsules (30 mg twice a day) or identical placebo for 12 weeks according to a randomized, double-blind, placebo-controlled study design. The primary efficacy endpoint was change in hemoglobin (Hb) from baseline to week 12. Safety and tolerability were assessed. Results: Of 329 patients screened, 128 received randomized therapy (64 ferric maltol-treated and 64 placebo-treated patients) and comprised the intent-to-treat efficacy analysis: 55 ferric maltol patients (86%) and 53 placebo patients (83%) completed the trial. Significant improvements in Hb were observed with ferric maltol versus placebo at weeks 4, 8, and 12: mean (SE) 1.04 (0.11) g/dL, 1.76 (0.15) g/dL, and 2.25 (0.19) g/dL, respectively (P < 0.0001 at all time-points; analysis of covariance). Hb was normalized in two-thirds of patients by week 12. The safety profile of ferric maltol was comparable with placebo, with no impact on inflammatory bowel disease severity. Conclusions: Ferric maltol provided rapid clinically meaningful improvements in Hb and showed a favorable safety profile, suggesting its possible use as an alternative to intravenous iron in IDA inflammatory bowel disease. PMID:25545376

  8. Synthesis of Fullerene-Fused Dioxanes/Dioxepanes: Ferric Perchlorate-Mediated One-Step Reaction of [60]Fullerene with Diols.

    PubMed

    Zhang, Xiao-Feng; Li, Fa-Bao; Wu, Jun; Shi, Ji-Long; Liu, Zhan; Liu, Li

    2015-06-19

    The facile one-step reaction of [60]fullerene with various diols in the presence of ferric perchlorate afforded a series of rare fullerene-fused dioxanes/dioxepanes. Nevertheless, the reaction of [60]fullerene with diethylene glycol, triethylene glycol, and tripropylene glycol promoted by ferric perchlorate unexpectedly generated fullerene-fused dioxanes instead of the anticipated fullerene-fused crown ethers. A plausible reaction mechanism is proposed to explain the formation of fullerene-fused dioxane/dioxepane products. PMID:25996442

  9. Ferric Hydrogensulfate [Fe(HSO4)3] As a Reusable Heterogeneous Catalyst for the Synthesis of 5-Substituted-1H-Tetrazoles and Amides

    PubMed Central

    Eshghi, Hossein; Seyedi, Seyed Mohammad; Zarei, Elaheh Rahimi

    2011-01-01

    Ferric hydrogensulfate catalyzed the synthesis of 5-substituted 1H-tetrazoles via [2?+?3] cycloaddition of nitriles and sodium azide. This method has the advantages of high yields, simple methodology, and easy workup. The catalyst can be recovered by simple filtration and reused delivering good yields. Also, ferric hydrogensulfate catalyzed the hydrolysis of nitriles to primary amides under aqueous conditions. Various aliphatic and aromatic nitriles converted to the corresponding amides in good yields without any contamination with carboxylic acids. PMID:24052817

  10. Hydride Attack on a Coordinated Ferric Nitrosyl: Experimental and DFT Evidence for the Formation of a Heme Model-HNO Derivative.

    PubMed

    Abucayon, Erwin G; Khade, Rahul L; Powell, Douglas R; Zhang, Yong; Richter-Addo, George B

    2016-01-13

    Heme-HNO species are crucial intermediates in several biological processes. To date, no well-defined Fe heme-HNO model compounds have been reported. Hydride attack on the cationic ferric [(OEP)Fe(NO)(5-MeIm)]OTf (OEP = octaethylporphyrinato dianion) generates an Fe-HNO product that has been characterized by IR and (1)H NMR spectroscopy. Results of DFT calculations reveal a direct attack of the hydride on the N atom of the coordinated ferric nitrosyl. PMID:26678216

  11. Melt densities in the CaO-FeO-Fe 2O 3-SiO 2 system and the compositional dependence of the partial molar volume of ferric iron in silicate melts

    NASA Astrophysics Data System (ADS)

    Dingwell, Donald B.; Brearley, Mark

    1988-12-01

    The densities of 10 melts in the CaO-FeO-Fe 2O 3-SiO 2 system were determined in equilibrium with air, in the temperature range of 1200 to 1550C, using the double-bob Archimedean technique. Melt compositions range from 6 to 58 wt% SiO 2, 14 to 76 wt% Fe 2O 3 and 10 to 46 wt% CaO. The ferric-ferrous ratios of glasses drop-quenched from loop fusion equilibration experiments were determined by 57Fe Mssbauer spectroscopy. Melt densities range from 2.689 to 3.618 gm/cm 3 with a mean standard deviation from replicate experiments of 0.15%. Least-squares regressions of molar volume versus molar composition have been performed and the root mean squared deviation shows that a linear combination of partial molar volumes for the oxide components (CaO, FeO, Fe 2O 3 and SiO 2) cannot describe the data set within experimental error. Instead, the inclusion of excess terms in CaFe 3+ and CaSi (product terms using the oxides) is required to yield a fit that describes the experimental data within error. The nonlinear compositional-dependence of the molar volumes of melts in this system can be explained by structural considerations of the roles of Ca and Fe 3+. The volume behavior of melts in this system is significantly different from that in the Na 2O-FeO-Fe 2O 3-SiO 2 system, consistent with the proposal that a proportion of Fe 3+ in melts in the CaO-FeO-Fe 2O 3-SiO 2 system is not tetrahedrally-coordinated by oxygen, which is supported by differences in 57Fe Mssbauer spectra of glasses. Specifically, this study confirms that the 57Fe Mssbauer spectra exhibit an area asymmetry and higher values of isomer shift of the ferric doublet that vary systematically with composition and temperature (this study; Dingwell and Virgo, 1987, 1988). These observations are consistent with a number of other lines of evidence ( e.g., homogeneous redox equilibria, Dickenson and Hess, 1986; viscosity, Dingwell and Virgo, 1987,1988). Two species of ferric iron, varying in proportions with temperature, composition and redox state, are sufficient to describe the above observations. The presence of more than one coordination geometry for Fe 3+ in low pressure silicate melts has several implications for igneous petrogenesis. The possible effects on compressibility, the pressure dependence of the redox ratio, and redox enthalpy are briefly noted.

  12. TRANSFORMATION OF NITROSOBENZENES AND HYDROXYLANILINES BY FE II SPECIES: ELUCIDATION OF MECHANISM, EFFECT OF FERRIC OXIDES AND PH

    EPA Science Inventory

    Nitrosobenzenes, the first intermediates in the reduction of nitrobenzenes, were reduced by Fe(II) solutions as well as by Fe(II)-treated goethite suspensions (Fe(II)/G). Results indicate a reactivity trend in which electron-withdrawing groups in the para position increased the ...

  13. Surface complexation modeling of Co(II) adsorption on mixtures of hydrous ferric oxide, quartz and kaolinite

    NASA Astrophysics Data System (ADS)

    Landry, Christopher J.; Koretsky, Carla M.; Lund, Tracy J.; Schaller, Melinda; Das, Soumya

    2009-07-01

    Co sorption was measured as a function of pH, ionic strength (0.001-0.1 M NaNO 3) and sorbate/sorbent ratio on pure quartz, HFO and kaolinite and on binary and ternary mixtures of the three solids. Sorption data measured for the pure solids were used to derive internally-consistent diffuse layer surface complexation model (DLM) stability constants for Co sorption. Co sorption on HFO could be adequately modeled over a broad range of ionic strengths and sorbate/sorbent ratios with a two variable-charge site model. Fits based on a single variable-charge site model were reasonable, but were improved by using ionic-strength dependent stability constants. A single variable-charge site model with an additional permanent ion exchange site produced the best fit to Co edges measured on kaolinite over a range of ionic strength and sorbate/sorbent ratios. These DLM fits were also improved by using ionic-strength dependent stability constants. The DLM approach could not adequately describe the slope of Co sorption edges on quartz. This study demonstrates that for accurate prediction of Co sorption over wide ranges of ionic strength and sorbate/sorbent ratio, the DLM may require ionic-strength dependent stability constants. DLM stability constants for Co sorption derived for the pure solids were used to predict sorption as a function of pH and solid concentration on binary and ternary mixtures of the three solids. Discrepancies between predictions and measurements were quantitatively similar to those observed for the pure mineral systems. Thus, a simple component additivity approach provides useful predictions of metal sorption in the mixed solid systems.

  14. TRANSFORMATION OF NITROSOBENZENES AND HYDROXYLANILINES BY FE (II) SPECIES: ELUCIDATION OF MECHANISM, EFFECT OF FERRIC OXIDES AND PH

    EPA Science Inventory

    The purpose of this work was to (i) study the effect of structure composition on the reactivity of a series of N-hydroxylaniline and nitrosobenzene compounds toward their reduction by Fe(II) species, (ii) evaluate the usefulness of several chemical parameters for predicting the r...

  15. Breakdown of Fe-Ringwoodite to Ferrosilite and Ferric Wadsleyite at high P and T and Oxidizing Conditions

    NASA Astrophysics Data System (ADS)

    Koch-Mller, M.; Rhede, D.; Schulz, R.; Wirth, R.

    2006-12-01

    The stability relations in the systems M2SiO4 (M = Mg, Fe, Ni, Co) have been the subject of numerous studies because of their significance for the mantle transition zone. In the Mg2SiO4 system three polymporphs exist: at ambient conditions olivine, at pressure > 13 GPa ( 1000 C) wadsleyite and at P > 18 GPa ( 1000 C) ringwoodite. This is quite different to the Fe2SiO4 system where no intervending wadsleyite phase has been observed but fayalite directly transforms to Fe- ringwoodite at 5.3 GPa ( 1000 C). Experiments in the system Fe2SiO4 Fe3O4 by Woodland and Angel (1998) at 5.6 GPa (1100 C) revealed that Fe-wadsleyite can only be stabilised if significant amounts of Fe3+ are incorporated leading to the formula Fe2.45Si0.55O4. To get deeper insight into the phase relation in the system Fe2SiO4 we investigated the phase relations as a function of P, T and fO2. The experiments were performed in a multi-anvil apparatus at 7 GPa and temperatures 1000 C. Oxygen fugacities were variied using the solid oxygen buffer systems Fe/FeO and Ni/NiO. The run products were analysed with electron microprobe, Raman spectroscopy, transmission electron microscopy including electron energy-loss spectroscopy and X-ray powder diffraction. The X-ray data were analysed using the GSAS software. At fO2 conditions corresponding to Fe/FeO Fe- ringwoodite is the stable phase with normal spinel structure. At fO2 between Fe/FeO and Ni/NiO the inversion grade and Fe3+ content of Fe-ringwoodite slightly increases leading to the formula (Fe1.96Si0.04)(Si0.95Fe0.05)O4. At fO2 corresponding to Ni/NiO fayalite transforms to ferrosilite and Fe-wadsleyite according to the reaction: 9 Fe2SiO4 + O2 = 6 FeSiO3 + 5 Fe2.42Si0.58O4. Refinement of site occupancies in combinations with stoichiometric Fe3+ calculations show that in wadsleyite 32 % of the total Fe is incorporated as Fe3+ according to Fe2+1.60Fe3+0.40Si0.62Fe3+0.38O4 whereas the ferrosilite seems to be free of Fe3+. Reference Woodland and Angel (1998) Crystal strucutre of a new spinelloid with the wadsleyite strucutre in the system Fe2SiO4 Fe3O4 and implications for the Earth's mantle. American Mineralogist 83, 404-408.

  16. Photocatalytic activity of ferric oxide/titanium dioxide nanocomposite films on stainless steel fabricated by anodization and ion implantation

    NASA Astrophysics Data System (ADS)

    Zhan, Wei-ting; Ni, Hong-wei; Chen, Rong-sheng; Yue, Gao; Tai, Jun-kai; Wang, Zi-yang

    2013-08-01

    A simple surface treatment was used to develop photocatalytic activity for stainless steel. AISI 304 stainless steel specimens after anodization were implanted by Ti ions at an extracting voltage of 50 kV with an implantation dose of 3 1015 atomscm-2 and then annealed in air at 450C for 2 h. The morphology was observed by scanning electron microscopy. The microstructure was characterized by X-ray diffraction and X-ray photoelectron spectroscopy. The photocatalytic degradation of methylene blue solution was carried out under ultraviolet light. The corrosion resistance of the stainless steel was evaluated in NaCl solution (3.5 wt%) by electrochemical polarization curves. It is found that the Ti ions depth profile resembles a Gaussian distribution in the implanted layer. The nanostructured Fe2O3/TiO2 composite film exhibits a remarkable enhancement in photocatalytic activity referenced to the mechanically polished specimen and anodized specimen. Meanwhile, the annealed Ti-implanted specimen remains good corrosion resistance.

  17. Variation of the oxidation state of verdoheme in the heme oxygenase reaction

    SciTech Connect

    Gohya, Tomohiko; Sato, Michihiko; Zhang Xuhong; Migita, Catharina T.

    2008-11-14

    Heme oxygenase (HO) converts hemin to biliverdin, CO, and iron applying molecular oxygen and electrons. During successive HO reactions, two intermediates, {alpha}-hydroxyhemin and verdoheme, have been generated. Here, oxidation state of the verdoheme-HO complexes is controversial. To clarify this, the heme conversion by soybean and rat HO isoform-1 (GmHO-1 and rHO-1, respectively) was compared both under physiological conditions, with oxygen and NADPH coupled with ferredoxin reductase/ferredoxin for GmHO-1 or with cytochrome P450 reductase for rHO-1, and under a non-physiological condition with hydrogen peroxide. EPR measurements on the hemin-GmHO-1 reaction with oxygen detected a low-spin ferric intermediate, which was undetectable in the rHO-1 reaction, suggesting the verdoheme in the six-coordinate ferric state in GmHO-1. Optical absorption measurements on this reaction indicated that the heme degradation was extremely retarded at verdoheme though this reaction was not inhibited under high-CO concentrations, unlike the rHO-1 reaction. On the contrary, the Gm and rHO-1 reactions with hydrogen peroxide both provided ferric low-spin intermediates though their yields were different. The optical absorption spectra suggested that the ferric and ferrous verdoheme coexisted in reaction mixtures and were slowly converted to the ferric biliverdin complex. Consequently, in the physiological oxygen reactions, the verdoheme is found to be stabilized in the ferric state in GmHO-1 probably guided by protein distal residues and in the ferrous state in rHO-1, whereas in the hydrogen peroxide reactions, hydrogen peroxide or hydroxide coordination stabilizes the ferric state of verdoheme in both HOs.

  18. Synthetic analogues of [Fe4S4(Cys)3(His)] in hydrogenases and [Fe4S4(Cys)4] in HiPIP derived from all-ferric [Fe4S4{N(SiMe3)2}4

    PubMed Central

    Ohki, Yasuhiro; Tanifuji, Kazuki; Yamada, Norihiro; Imada, Motosuke; Tajima, Tomoyuki; Tatsumi, Kazuyuki

    2011-01-01

    The all-ferric [Fe4S4]4+ cluster [Fe4S4{N(SiMe3)2}4] 1 and its one-electron reduced form [1]- serve as convenient precursors for the synthesis of 3∶1-site differentiated [Fe4S4] clusters and high-potential iron-sulfur protein (HiPIP) model clusters. The reaction of 1 with four equivalents (equiv) of the bulky thiol HSDmp (Dmp = 2,6-(mesityl)2C6H3, mesityl = 2,4,6-Me3C6H2) followed by treatment with tetrahydrofuran (THF) resulted in the isolation of [Fe4S4(SDmp)3(THF)3] 2. Cluster 2 contains an octahedral iron atom with three THF ligands, and its Fe(S)3(O)3 coordination environment is relevant to that in the active site of substrate-bound aconitase. An analogous reaction of [1]- with four equiv of HSDmp gave [Fe4S4(SDmp)4]- 3, which models the oxidized form of HiPIP. The THF ligands in 2 can be replaced by tetramethyl-imidazole (Me4Im) to give [Fe4S4(SDmp)3(Me4Im)] 4 modeling the [Fe4S4(Cys)3(His)] cluster in hydrogenases, and its one-electron reduced form [4]- was synthesized from the reaction of 3 with Me4Im. The reversible redox couple between 3 and [3]- was observed at E1/2 = -820 mV vs. Ag/Ag+, and the corresponding reversible couple for 4 and [4]- is positively shifted by +440 mV. The cyclic voltammogram of 3 also exhibited a reversible oxidation couple, which indicates generation of the all-ferric [Fe4S4]4+ cluster, [Fe4S4(SDmp)4]. PMID:21768339

  19. Synthetic analogues of [Fe4S4(Cys)3(His)] in hydrogenases and [Fe4S4(Cys)4] in HiPIP derived from all-ferric [Fe4S4{N(SiMe3)2}4].

    PubMed

    Ohki, Yasuhiro; Tanifuji, Kazuki; Yamada, Norihiro; Imada, Motosuke; Tajima, Tomoyuki; Tatsumi, Kazuyuki

    2011-08-01

    The all-ferric [Fe(4)S(4)](4+) cluster [Fe(4)S(4){N(SiMe(3))(2)}(4)] 1 and its one-electron reduced form [1](-) serve as convenient precursors for the synthesis of 31-site differentiated [Fe(4)S(4)] clusters and high-potential iron-sulfur protein (HiPIP) model clusters. The reaction of 1 with four equivalents (equiv) of the bulky thiol HSDmp (Dmp = 2,6-(mesityl)(2)C(6)H(3), mesityl = 2,4,6-Me(3)C(6)H(2)) followed by treatment with tetrahydrofuran (THF) resulted in the isolation of [Fe(4)S(4)(SDmp)(3)(THF)(3)] 2. Cluster 2 contains an octahedral iron atom with three THF ligands, and its Fe(S)(3)(O)(3) coordination environment is relevant to that in the active site of substrate-bound aconitase. An analogous reaction of [1](-) with four equiv of HSDmp gave [Fe(4)S(4)(SDmp)(4)](-) 3, which models the oxidized form of HiPIP. The THF ligands in 2 can be replaced by tetramethyl-imidazole (Me(4)Im) to give [Fe(4)S(4)(SDmp)(3)(Me(4)Im)] 4 modeling the [Fe(4)S(4)(Cys)(3)(His)] cluster in hydrogenases, and its one-electron reduced form [4](-) was synthesized from the reaction of 3 with Me(4)Im. The reversible redox couple between 3 and [3](-) was observed at E(1/2) = -820 mV vs. Ag/Ag(+), and the corresponding reversible couple for 4 and [4](-) is positively shifted by +440 mV. The cyclic voltammogram of 3 also exhibited a reversible oxidation couple, which indicates generation of the all-ferric [Fe(4)S(4)](4+) cluster, [Fe(4)S(4)(SDmp)(4)]. PMID:21768339

  20. Iron-reducing bacteria accumulate ferric oxyhydroxide nanoparticle aggregates that may support planktonic growth

    PubMed Central

    Luef, Birgit; Fakra, Sirine C; Csencsits, Roseann; Wrighton, Kelly C; Williams, Kenneth H; Wilkins, Michael J; Downing, Kenneth H; Long, Philip E; Comolli, Luis R; Banfield, Jillian F

    2013-01-01

    Iron-reducing bacteria (FeRB) play key roles in anaerobic metal and carbon cycling and carry out biogeochemical transformations that can be harnessed for environmental bioremediation. A subset of FeRB require direct contact with Fe(III)-bearing minerals for dissimilatory growth, yet these bacteria must move between mineral particles. Furthermore, they proliferate in planktonic consortia during biostimulation experiments. Thus, a key question is how such organisms can sustain growth under these conditions. Here we characterized planktonic microbial communities sampled from an aquifer in Rifle, Colorado, USA, close to the peak of iron reduction following in situ acetate amendment. Samples were cryo-plunged on site and subsequently examined using correlated two- and three-dimensional cryogenic transmission electron microscopy (cryo-TEM) and scanning transmission X-ray microscopy (STXM). The outer membranes of most cells were decorated with aggregates up to 150 nm in diameter composed of ∼3 nm wide amorphous, Fe-rich nanoparticles. Fluorescent in situ hybridization of lineage-specific probes applied to rRNA of cells subsequently imaged via cryo-TEM identified Geobacter spp., a well-studied group of FeRB. STXM results at the Fe L2,3 absorption edges indicate that nanoparticle aggregates contain a variable mixture of Fe(II)–Fe(III), and are generally enriched in Fe(III). Geobacter bemidjiensis cultivated anaerobically in the laboratory on acetate and hydrous ferric oxyhydroxides also accumulated mixed-valence nanoparticle aggregates. In field-collected samples, FeRB with a wide variety of morphologies were associated with nano-aggregates, indicating that cell surface Fe(III) accumulation may be a general mechanism by which FeRB can grow while in planktonic suspension. PMID:23038172