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1

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

NASA Technical Reports Server (NTRS)

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).

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

1994-01-01

2

Mid-infrared transmission spectra of crystalline and nanophase iron oxides/oxyhydroxides and implications for remote sensing of Mars  

NASA Technical Reports Server (NTRS)

Ferric-iron-bearing materials play an important role in the interpretation of visible to near-IR Mars spectra, and they may play a similarly important role in the analysis of new mid-IR spacecraft spectral observations to be obtained over the next decade. We review existing data on mid-IR transmission spectra of ferric oxides/oxyhydroxides and present new transmission spectra for ferric-bearing materials spanning a wide range of mineralogy and crystallinity. These materials include 11 samples of well-crystallized ferric oxides (hematite, maghemite, and magnetite) and ferric oxyhydroxides (goethite, lepidocrocite). We also report the first transmission spectra for purely nanophase ferric oxide samples that have been shown to exhibit spectral similarities to Mars in the visible to near-IR and we compare these data to previous and new transmission spectra of terrestrial palagonites. Most of these samples show numerous, diagnostic absorption features in the mid-IR due to Fe(3+)-O(2-) vibrational transitions, structural and/or bound OH, and/or silicates. These data indicate that high spatial resolution, moderate spectral resolution mid-IR ground-based and spacecraft observations of Mars may be able to detect and uniquely discriminate among different ferric-iron-bearing phases on the Martian surface or in the airborne dust.

Bell, James F., III; Roush, Ted L.; Morris, Richard V.

1995-01-01

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)

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.

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

2006-01-01

4

Characterization of Navajo sandstone hydrous ferric oxide concretions.  

E-print Network

??In Utah's Grand Staircase Escalante National Monument (GSENM), abundant spheroidal hydrous ferric oxide (HFO) concretions (cemented mineral masses) of the Jurassic Navajo Sandstone are present… (more)

Potter, Sally Latham

2009-01-01

5

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

PubMed

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. PMID:11539577

Morris, R V; Golden, D C; Bell JF 3rd; Lauer, H V; Adams, J B

1993-10-01

6

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

PubMed Central

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

Brock, T D; Gustafson, J

1976-01-01

7

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

NASA Technical Reports Server (NTRS)

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.

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

2012-01-01

8

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...

9

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

SciTech Connect

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.

Garaje, Sunil N.; Apte, Sanjay K. [Nanocomposite Group, Centre for Materials for Electronics Technology (C-MET), Department of Electronics and Information Technology (DeitY), Government of India, Panchawati, Off Pashan Road, Pune 411008 (India)] [Nanocomposite Group, Centre for Materials for Electronics Technology (C-MET), Department of Electronics and Information Technology (DeitY), Government of India, Panchawati, Off Pashan Road, Pune 411008 (India); Kumar, Ganpathy [Department of Electrical and Computer Engineering, Tennessee Technological University, 1 William L. Jones Drive, Cookeville, TN 38505 (United States)] [Department of Electrical and Computer Engineering, Tennessee Technological University, 1 William L. Jones Drive, Cookeville, TN 38505 (United States); Panmand, Rajendra P.; Naik, Sonali D. [Nanocomposite Group, Centre for Materials for Electronics Technology (C-MET), Department of Electronics and Information Technology (DeitY), Government of India, Panchawati, Off Pashan Road, Pune 411008 (India)] [Nanocomposite Group, Centre for Materials for Electronics Technology (C-MET), Department of Electronics and Information Technology (DeitY), Government of India, Panchawati, Off Pashan Road, Pune 411008 (India); Mahajan, Satish M., E-mail: smahajan@tntech.edu [Department of Electrical and Computer Engineering, Tennessee Technological University, 1 William L. Jones Drive, Cookeville, TN 38505 (United States); Chand, Ramesh [Ministry of Communications and Information Technology, Department of Electronics and Information Technology (DeitY), Electronics Niketan, 6, CGO Complex, New Delhi 110003 (India)] [Ministry of Communications and Information Technology, Department of Electronics and Information Technology (DeitY), Electronics Niketan, 6, CGO Complex, New Delhi 110003 (India); Kale, Bharat B., E-mail: bbkale@cmet.gov.in [Nanocomposite Group, Centre for Materials for Electronics Technology (C-MET), Department of Electronics and Information Technology (DeitY), Government of India, Panchawati, Off Pashan Road, Pune 411008 (India)

2013-02-15

10

[Bioavailability of nanoparticles of ferric oxide when used in nutrition. Experimental results in rats].  

PubMed

Bioavailability of iron (Fe) introduced in the form of nanoparticles of ferric oxide and ferric sulphate was characterized in rats receiving Fe-deficient semi synthetic diet. Shown that nanoparticles of ferric oxide as well as the traditional form of this trace element (soluble salt of Fe) can restore the status of this trace element disturbances due to its scarcity in the diet. PMID:21842750

Raspopov, R V; Trushina, É N; Gmoshinski?, I V; Khotimchenko, S A

2011-01-01

11

Acoustical investigations of borate glasses containing oxides of some transition elements and ferric oxide dopants  

NASA Astrophysics Data System (ADS)

Glass samples of manganese oxide borate and zinc oxide borate (with and without ferric oxide doping) have been prepared to study their acoustical, mechanical, and thermal behavior as function of composition. Sound velocities and attenuation measurements in these glass systems at 1,2, and 5 MHz give elastic moduli, Poissons ratio, micro-hardness, acoustic impedance, internal friction, thermal expansion coefficient and Debye and softening temperatures. Structural changes involve boron anomaly, field strengths of cations, difference in ionic radii, and charge state of iron. Makishima-Mackenzie (theoretical model) and IR and NGR techniques confirm the conclusions arrived at. The network modifier (NWM) is varied from 25 to 45 mol% for manganese oxide borate and from 15 to 40 mol% with 10 mol% doping of ferric oxide. For zinc oxide borate glasses, it varies from 26 to 34 mol% and with 10 mol% of ferric oxide, its variation is from 15 to 35 mol%. Impact of doping by ferric oxide on the properties of these glass systems have been investigated.

Bhatti, Surjit Singh; Singh, Kanwar Jit

2003-04-01

12

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

NASA Technical Reports Server (NTRS)

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.

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

1992-01-01

13

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...

14

Dietary bioavailability of Cu adsorbed to colloidal hydrous ferric oxide  

USGS Publications Warehouse

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.

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

2013-01-01

15

Mössbauer study of ferric oxide particles as products of thermal decomposition of iron\\/III\\/benzoate  

Microsoft Academic Search

The products of the thermal decomposition in air of iron\\/III\\/benzoate [Fe3\\/C6H5COO\\/6\\/OH\\/2]OH.H2O have been studied using conventional thermal analysis, X-ray diffraction measurements and mainly Mössbauer spectroscopy. The decomposition occurs in the temperature range 200–350°C. It was possible to identify benzoic acid and ferric oxide as final products. Above 300°C, the observed ferric oxide showed a particle size distribution, which depends on

A. Abras; M. M. Braga; J. C. Machado

1984-01-01

16

Oxygen isotope fractionation in ferric oxide-water systems: Low temperature synthesis  

NASA Astrophysics Data System (ADS)

The magnitude and temperature-sensitivity of oxygen isotope fractionation in ferric oxide-water systems remain uncertain. In this study, three different synthetic methods are used to investigate the temperature dependence of the fractionation between water and hematite, akaganeite, and goethite at near-surface temperatures. Our results reveal two similarities among these ferric oxide-water systems. First, the fractionation of oxygen isotopes between water and ferric oxide is small (i.e., ferric oxide-water fractionation factors [?] are very close to 1.000). Second, these ? values are relatively insensitive to change in temperature ( T). Hematite-water has a slightly higher ? value and a greater temperature sensitivity than goethite-water at surface temperatures. While the issue requires further study, we speculate that differences in the washing and drying protocols applied to final precipitates may be one of the factors that have contributed to the discrepancies among published ?- T curves. Owing to the rapid exchange of oxygen among the various hydrolytic Fe(III) species and ambient water, oxygen isotope equilibrium is probably attained between water and the ferric oxide gels and poorly-ordered ferrihydrite that are the initial precipitates in nearly all natural settings. Aging experiments suggest that isotopic compositions carried by ferric oxide gels and ferrihydrite are almost entirely erased by later exchange with ambient water during the maturation processes leading to formation of either hematite or goethite. These results suggest that dissolution and reprecipitation occur in the supposedly "solid-state transformation" from ferrihydrite to hematite. Thus the ? 18O value of natural crystalline ferric oxides may provide a record of the long-term average ? 18O value of local surface water, rather than that of the water from which the solid ferric oxide first formed.

Bao, Huiming; Koch, Paul L.

1999-03-01

17

Oxygen isotope fractionation in ferric oxide-water systems: low temperature synthesis  

Microsoft Academic Search

The magnitude and temperature-sensitivity of oxygen isotope fractionation in ferric oxide-water systems remain uncertain. In this study, three different synthetic methods are used to investigate the temperature dependence of the fractionation between water and hematite, akaganeite, and goethite at near-surface temperatures. Our results reveal two similarities among these ferric oxide-water systems. First, the fractionation of oxygen isotopes between water and

Huiming Bao; PAUL L. KOCH

1999-01-01

18

Estimation of surface precipitation constants for sorption of divalent metals onto hydrous ferric oxide and calcite  

E-print Network

oxide and calcite Chen Zhu * Department of Geology and Planetary Science, University of Pittsburgh for modeling surface precipitation of divalent metals, M2+ , onto hydrous ferric oxide and calcite were+ . D 2002 Elsevier Science B.V. All rights reserved. Keywords: Surface adsorption; Iron oxide; Calcite

Polly, David

19

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

NASA Astrophysics Data System (ADS)

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.

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

2012-07-01

20

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

PubMed Central

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

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

2013-01-01

21

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

NASA Astrophysics Data System (ADS)

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 process—oxidogenesis composed of a complex of microprocesses of biogenic and abiogenic nature.

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

2007-06-01

22

Sorption of Cadmium on Hydrous Ferric Oxide at High Sorbate/Sorbent Ratios: Equilibrium, Kinetics, and Modeling  

E-print Network

Sorption of Cadmium on Hydrous Ferric Oxide at High Sorbate/Sorbent Ratios: Equilibrium, Kinetics modelwithout addition of fittingparameters. The kinetics of cadmium sorptionslow considerablyasthesorbate existing data sets. In this paper we report on an experimental study of cadmium sorption on hydrous ferric

Morel, FranƧois M. M.

23

Aqueous pyrite oxidation by dissolved oxygen and by ferric iron  

Microsoft Academic Search

Rates of aqueous, abiotic pyrite oxidation were measured in oxygen-saturated and anaerobic Fe(III)-saturated solutions with initial pH from 2 to 9. These studies included analyses of sulfite, thiosulfate, polythionates, and sulfate, and procedures for cleaning oxidation products from pyrite surfaces were evaluated. Pyrite oxidation in oxygen-saturated solutions produced (1) rates that were only slightly dependent on initial pH, (2) linear

C. O. Moses; D. K. Nordstrom; J. S. Herman; A. L. Mills

1987-01-01

24

Soluble microbial products decrease pyrite oxidation by ferric iron at pH < 2.  

PubMed

Research on microbial activity in acid mine drainage (AMD) has focused on transformations of iron and sulfur. However, carbon cycling, including formation of soluble microbial products (SMP) from cell growth and decay, is an important biogeochemical component of the AMD environment. Experiments were conducted to study the interaction of SMP with soluble ferric iron in acidic conditions, particularly the formation of complexes that inhibit its effectiveness as the primary oxidant of pyrite during AMD generation. The rate of pyrite oxidation by ferric iron in sterile suspensions at pH 1.8 was reduced by 87% in the presence of SMP produced from autoclaved cells at a ratio of 0.3 mg DOC per mg total soluble ferric iron. Inhibition of pyrite oxidation by SMP was shown to be comparable to, but weaker than, the effect of a chelating synthetic siderophore, DFAM. Two computational models incorporating SMP complexation were fitted to experimental results. Results suggest that bacterially produced organic matter can play a role in slowing pyrite oxidation. PMID:23777272

Yacob, Tesfayohanes; Pandey, Sachin; Silverstein, Joann; Rajaram, Harihar

2013-08-01

25

Sorption of Ferric Iron from Ferrioxamine B to Synthetic and Biogenic Layer Type Manganese Oxides  

NASA Astrophysics Data System (ADS)

Siderophores are biogenic chelating agents produced in terrestrial and marine environments to increase the bioavailablity of ferric iron. Recent work has suggested that both aqueous and solid-phase Mn(III) may affect siderophore-mediated iron transport, but no information appears to be available about the effect of solid-phase Mn(IV). To probe the effects of predominantly Mn(IV) oxides, we studied the sorption reaction of ferrioxamine B [Fe(III)HDFOB+, an Fe(III) chelate of the trihydroxamate siderophore desferrioxamine B (DFOB)] with two synthetic birnessites [layer type Mn(III, IV) oxides] and a biogenic birnessite produced by Pseudomonas putida MnB1. We found that all of these predominantly Mn(IV) oxides greatly reduced the aqueous concentration of Fe(III)HDFOB+ over at pH 8. After 72 hours equilibration time, the sorption behavior for the synthetic birnessites could be accurately described by a Langmuir isotherm; for the biogenic oxide, a Freundlich isotherm was best utilized to model the sorption data. To study the molecular nature of the interaction between the Fe(III)HDFOB+ complex and the oxide surface, Fe K-edge extended X-ray absorption fine structure (EXAFS) spectroscopy was employed. Analysis of the EXAFS spectra indicated that Fe(III) associated with the Mn(IV) oxides is not complexed by DFOB as in solution, but instead Fe(III) is specifically adsorbed to into the mineral structure at multiple sites with no evidence of DFOB complexation, thus indicating that the Mn(IV) oxides displaced Fe(III) from the siderophore complex. These results indicate that manganese oxides, including biominerals, may strongly sequester iron from soluble ferric complexes and thus may play a significant role in the biogeochemical cycling of iron in marine and terrestrial environments.

Duckworth, O.; John, B.; Sposito, G.

2006-12-01

26

Sorption of ferric iron from ferrioxamine B to synthetic and biogenic layer type manganese oxides  

NASA Astrophysics Data System (ADS)

Siderophores are biogenic chelating agents produced in terrestrial and marine environments that increase the bioavailability of ferric iron. Recent work has suggested that both aqueous and solid-phase Mn(III) may affect siderophore-mediated iron transport, but scant information appears to be available about the potential roles of layer type manganese oxides, which are relatively abundant in soils and the oligotrophic marine water column. To probe the effects of layer type manganese oxides on the stability of aqueous Fe-siderophore complexes, we studied the sorption of ferrioxamine B [Fe(III)HDFOB +, an Fe(III) chelate of the trihydroxamate siderophore desferrioxamine B (DFOB)] to two synthetic birnessites [layer type Mn(III,IV) oxides] and a biogenic birnessite produced by Pseudomonas putida GB-1. We found that all of these predominantly Mn(IV) oxides greatly reduced the aqueous concentration of Fe(III)HDFOB + at pH 8. Analysis of Fe K-edge EXAFS spectra indicated that a dominant fraction of Fe(III) associated with the Mn(IV) oxides is not complexed by DFOB as in solution, but instead Fe(III) is specifically adsorbed to the mineral structure at multiple sites, thus indicating that the Mn(IV) oxides displaced Fe(III) from the siderophore complex. These results indicate that layer type manganese oxides, including biogenic minerals, may sequester iron from soluble ferric complexes. We conclude that the sorption of iron-siderophore complexes may play a significant role in the bioavailability and biogeochemical cycling of iron in marine and terrestrial environments.

Duckworth, Owen W.; Bargar, John R.; Sposito, Garrison

2008-07-01

27

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

NASA Technical Reports Server (NTRS)

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.

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

2004-01-01

28

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

NASA Astrophysics Data System (ADS)

We have used room temperature and cryogenic 57Fe Mössbauer 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 Mössbauer 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 (Mössbauer quadrupole splitting), smaller primary particle size (magnetometry blocking temperature), weaker Fe to particle bond strength (Mössbauer 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.

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

2005-02-01

29

Structure and stability of Cd[sup 2+] surface complexes on ferric oxides; 1: Results from EXAFS spectroscopy  

Microsoft Academic Search

In the environment, such different processes as transport and availability of contaminants in soils, scavenging and release of trace elements in water cycles, wastewater treatment, and groundwater protection are intimately correlated with interfacial chemical reactions. Extended X-ray absorption fine structure (EXAFS) spectroscopy has been used to study the adsorption and coprecipitation mechanism of Cd(II) on hydrous ferric oxide (HFO) and

L. Spadini; A. Manceau; L. Charlet; P. W. Schindler

1994-01-01

30

Ferric oxides in East Candor Chasma, Valles Marineris (Mars) inferred from analysis of OMEGA/Mars Express data  

E-print Network

) inferred from analysis of OMEGA/Mars Express data: Identification and geological interpretation, J. Geophys (Observatoire pour la MineĀ“ralogie, l'Eau, les Glaces et l'ActiviteĀ“) imaging spectrometer onboard Mars ExpressFerric oxides in East Candor Chasma, Valles Marineris (Mars) inferred from analysis of OMEGA/Mars

Mege, Daniel

31

Abstract No. pan0505 Sorption of Heavy Metal Contaminants onto Hydrated Ferric Oxides: Mechanistic Modeling using X-ray  

E-print Network

Abstract No. pan0505 Sorption of Heavy Metal Contaminants onto Hydrated Ferric Oxides: Mechanistic the fate of heavy metal contaminants, such as lead, zinc, and nickel in soils and aquatic environments. Hence, to understand the mobility and bioavailability of these metal contaminants, these sorption

Sparks, Donald L.

32

Ion sorption onto hydrous ferric oxides: Effect on major element fluid chemistry at Aspo, Sweden  

SciTech Connect

The observed variability of fluid chemistry at the Aespoe Hard Rock Laboratory is not fully described by conservative fluid mixing models. Ion exchange may account for some of the observed discrepancies. It is also possible that variably charged solids such as oxyhydroxides of Fe can serve as sources and sinks of anions and cations through surface complexation. Surface complexation reactions on hydrous ferric oxides involve sorption of both cations and anions. Geochemical modeling of the surface chemistry of hydrous ferric oxides (HFOs) in equilibrium with shallow HBH02 and deep KA0483A waters shows that HFOs can serve as significant, pH-sensitive sources and sinks for cations and anions. Carbonate sorption is favored especially at below-neutral pH. A greater mass of carbonate is sorbed onto HFO surfaces than is contained in the fluid when 10 g goethite, used as a proxy for HFOs, is in contact with 1 kg H{sub 2}O. The masses of sorbent required to significantly impact fluid chemistry through sorption/desorption reactions seem to be reasonable when compared to the occurrences of HFOs at Aespoe. Thus, it is possible that small changes in fluid chemistry can cause significant releases of cations or anions from HFOs into the fluid phase or, alternately, result in uptake of aqueous species onto HFO surfaces. Simulations of the mixing of shallow HBH02 and native KA0483A waters in the presence of a fixed mass of goethite show that surface complexation does not cause the concentrations of Ca, Sr, and SO{sub 4} to deviate from those that are predicted using conservative mixing models. Results for HCO{sub 3} are more difficult to interpret and cannot be addressed adequately at this time.

Bruton, C.J.; Viani, B.E.

1996-06-01

33

Occurrence of surface polysulfides during the interaction between ferric (hydr)oxides and aqueous sulfide.  

PubMed

Polysulfides are often referred to as key reactants in the sulfur cycle, especially during the interaction of ferric (hydr)oxides and sulfide, forming ferrous-sulphide minerals. Despite their potential relevance, the extent of polysulfide formation and its relevance for product formation pathways remains enigmatic. We applied cryogenic X-ray Photoelectron Spectroscopy and wet chemical analysis to study sulfur oxidation products during the reaction of goethite and lepidocrocite with aqueous sulfide at different initial Fe/S molar ratios under anoxic conditions at neutral pH. The higher reactivity of lepidocrocite leads to faster and higher electron turnover compared to goethite. We were able to demonstrate for the first time the occurrence of surface-associated polysulfides being the main oxidation products in the presence of both minerals, with a predominance of disulfide (S2(2-)(surf)), and elemental sulfur. Concentrations of aqueous polysulfide species were negligible (<1%). With prior sulfide fixation by zinc acetate, the surface-associated polysulfides could be precipitated as zerovalent sulfur (S°), which was extracted by methanol thereafter. Of the generated S°, 20-34% were associated with S2(2-)(surf). Varying the Fe/S ratio revealed that surface polysulfide formation only becomes dominant when the remaining aqueous sulfide concentration is low (<0.03 mmol L(-1)). We hypothesize these novel surface sulfur species, particularly surface disulfide, to act as pyrite precursors. We further propose that these species play an overlooked role in the sulfur cycle. PMID:24735157

Wan, Moli; Shchukarev, Andrey; Lohmayer, Regina; Planer-Friedrich, Britta; Peiffer, Stefan

2014-05-01

34

Synergistic Competitive Inhibition of Ferrous Iron Oxidation by Thiobacillus ferrooxidans by Increasing Concentrations of Ferric Iron and Cells  

PubMed Central

Oxidation of ferrous iron by Thiobacillus ferrooxidans SM-4 was inhibited competitively by increasing concentrations of ferric iron or cells. A kinetic analysis showed that binding of one inhibitor did not exclude binding of the other and led to synergistic inhibition by the two inhibitors. Binding of one inhibitor, however, was affected by the other inhibitor, and the apparent inhibition constant increased with increasing concentrations of the other inhibitor. PMID:16348031

Lizama, Hector M.; Suzuki, Isamu

1989-01-01

35

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

NASA Astrophysics Data System (ADS)

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.

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

2003-07-01

36

Advanced phosphorus removal from membrane filtrates by adsorption on activated aluminium oxide and granulated ferric hydroxide.  

PubMed

The advanced phosphorus (P) removal by adsorption was studied for its suitability as a post-treatment step for membrane bioreactor (MBR) effluents low in P concentration and particle content. Two commercial adsorbents, granulated ferric hydroxide (GFH) and activated aluminium oxide (AA), were studied in batch tests and lab-scale filter tests for P adsorption in MBR filtrates. GFH showed a higher maximum capacity for phosphate and a higher affinity at low P concentrations compared to AA. Competition by inorganic ions was negligible for both adsorbents at the original pH (8.2). When equilibrium P concentrations exceeded 2 mg L(-1) in the spiked MBR filtrates, a precipitation of calcium phosphates occurred additionally to adsorption. During column studies the effluent criteria of 50 microgL(-1) P was reached after a throughput of 8000 bed volumes for GFH and 4000 for AA. Dissolved organic carbon appears to be the strongest competitor for adsorption sites. A partial regeneration and reloading of both adsorbents could be achieved by the use of sodium hydroxide. PMID:15325178

Genz, Arne; Kornmüller, Anja; Jekel, Martin

2004-09-01

37

Platinum-CatalyzedOxidations of Organic Compounds by Ferric Sulfate: Use of a Redox Fuel Cell to Mediate Complete Oxidation of  

E-print Network

and on reaction conditions. A redox fuelcell that catalyzedthe completeoxidation of ethyl- ene glycolby dioxygenatPlatinum-CatalyzedOxidations of Organic Compounds by Ferric Sulfate: Use of a Redox Fuel Cell) at the anode of the cell. A V(V)IV(IV)/HNO3IO2redox system was used to catalyze the electrochemical reduction

Prentiss, Mara

38

Comparative study of pulmonary responses to nano- and submicron-sized ferric oxide in rats.  

PubMed

Ferric oxide (Fe(2)O(3)) nanoparticles are of considerable interest for application in nanotechnology related fields. However, as iron being a highly redox-active transition metal, the safety of iron nanomaterials need to be further studied. In this study, the size, dose and time dependent of Fe(2)O(3) nanoparticle on pulmonary and coagulation system have been studied after intratracheal instillation. The Fe(2)O(3) nanoparticles with mean diameters of 22 and 280 nm, respectively, were intratracheally instilled to male Sprague Dawley rats at low (0.8 mg/kgbw) and high (20 mg/kgbw) doses. The toxic effects were monitored in the post-instilled 1, 7 and 30 days. Our results showed that the Fe(2)O(3) nanoparticle exposure could induce oxidative stress in lung. Alveolar macrophage (AM) over-loading of phagocytosed nanoparticle by high dose treatment had occurred, while the non-phagocytosed particles were found entering into alveolar epithelial in day 1 after exposure. Several inflammatory reactions including inflammatory and immune cells increase, clinical pathological changes: follicular hyperplasia, protein effusion, pulmonary capillary vessel hyperaemia and alveolar lipoproteinosis in lung were observed. The sustain burden of particles in AM and epithelium cells has caused lung emphysema and pro-sign of lung fibrosis. At the post-instilled day 30, the typical coagulation parameters, prothrombin time (PT) and activated partial thromboplastin time (APTT) in blood of low dose 22 nm-Fe(2)O(3) treated rats were significantly longer than the controls. We concluded that both of the two-sized Fe(2)O(3) particle intratracheal exposure could induce lung injury. Comparing with the submicron-sized Fe(2)O(3) particle, the nano-sized Fe(2)O(3) particle may increase microvascular permeability and cell lysis in lung epitheliums and disturb blood coagulation parameters significantly. PMID:18394769

Zhu, Mo-Tao; Feng, Wei-Yue; Wang, Bing; Wang, Tian-Cheng; Gu, Yi-Qun; Wang, Meng; Wang, Yun; Ouyang, Hong; Zhao, Yu-Liang; Chai, Zhi-Fang

2008-05-21

39

Ferrous iron oxidation under acidic conditions - The effect of ferric oxide surfaces  

NASA Astrophysics Data System (ADS)

In this study, the kinetics of Fe(II) oxidation in the presence of the iron oxyhydroxides ferrihydrite, Si-ferrihydrite, schwertmannite, lepidocrocite and goethite are investigated over the pH range 4-5.5. Despite limited sorption of Fe(II), the rate of Fe(II) oxidation is up to 70-fold faster than in the absence of any Fe oxyhydroxide phase over pH 4.5-5.5. Enhanced Fe(II) oxidation was minor or negligible at pH 4 with undetectable amounts of Fe(II) adsorbed to the iron oxyhydroxides at this pH. Heterogeneous rate constants derived from kinetic modeling were normalized to the concentration of adsorbed Fe(II) and deviated by no more than 13.8% at pH 4.5, 5 and 5.5, indicating that oxidation is proportional to the concentration of adsorbed Fe(II). Average rate constants were found to be: 2.12 ± 0.20, 1.30 ± 0.09, 1.69 ± 0.22, 1.20 ± 0.08 and 0.68 ± 0.09 M-1 s-1 for ferrihydrite, goethite, lepidocrocite, schwertmannite and Si-ferrihydrite, respectively. The role of reactive oxygen species, such as hydrogen peroxide, the hydroxyl radical and superoxide, towards the overall oxidation of Fe(II) was examined but found to have only a minor impact on Fe(II) oxidation when compared to the effect of heterogeneous oxidation.

Jones, Adele M.; Griffin, Phillipa J.; Collins, Richard N.; Waite, T. David

2014-11-01

40

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

USGS Publications Warehouse

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.

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

2004-01-01

41

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

PubMed

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

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

2014-02-01

42

Kinetics of anaerobic elemental sulfur oxidation by ferric iron in Acidithiobacillus ferrooxidans and protein identification by comparative 2-DE-MS/MS.  

PubMed

Elemental sulfur oxidation by ferric iron in Acidithiobacillus ferrooxidans was investigated. The apparent Michaelis constant for ferric iron was 18.6 mM. An absence of anaerobic ferric iron reduction ability was observed in bacteria maintained on elemental sulfur for an extended period of time. Upon transition from ferrous iron to elemental sulfur medium, the cells exhibited similar kinetic characteristics of ferric iron reduction under anaerobic conditions to those of cells that were originally maintained on ferrous iron. Nevertheless, a total loss of anaerobic ferric iron reduction ability after the sixth passage in elemental sulfur medium was demonstrated. The first proteomic screening of total cell lysates of anaerobically incubated bacteria resulted in the detection of 1599 protein spots in the master two-dimensional electrophoresis gel. A set of 59 more abundant and 49 less abundant protein spots that changed their protein abundances in an anaerobiosis-dependent manner was identified and compared to iron- and sulfur-grown cells, respectively. Proteomic analysis detected a significant increase in abundance under anoxic conditions of electron transporters, such as rusticyanin and cytochrome c(552), involved in the ferrous iron oxidation pathway. Therefore we suggest the incorporation of rus-operon encoded proteins in the anaerobic respiration pathway. Two sulfur metabolism proteins were identified, pyridine nucleotide-disulfide oxidoreductase and sulfide-quinone reductase. The important transcription regulator, ferric uptake regulation protein, was anaerobically more abundant. The anaerobic expression of several proteins involved in cell envelope formation indicated a gradual adaptation to elemental sulfur oxidation. PMID:22057833

Kucera, Jiri; Bouchal, Pavel; Cerna, Hana; Potesil, David; Janiczek, Oldrich; Zdrahal, Zbynek; Mandl, Martin

2012-03-01

43

The kinetics of the oxidation of pyrite by ferric ions and dissolved oxygen: an electrochemical study  

Microsoft Academic Search

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

Paul R. Holmes; Frank K. Crundwell

2000-01-01

44

Synthesis of petal-like ferric oxide/cysteine architectures and their application in affinity separation of proteins.  

PubMed

Petal-like ferric oxide/cysteine (FeOOH/Cys) architectures were prepared through a solvothermal route, which possessed high thiol group density. These thiol groups as binding sites can chelate Ni(2+) ions, which can be further used to enrich and separate his-tagged proteins directly from the mixture of lysed cells without sample pretreatment. These results show that the FeOOH/Cys architectures with immobilized Ni(2+) ions present negligible nonspecific protein adsorption and high protein adsorption capacity, with the saturation capacity being 88mg/g, which are especially suitable for purification of his-tagged proteins. PMID:24268283

Zou, Xueyan; Li, Kun; Yin, Yanbin; Zhao, Yanbao; Zhang, Yu; Li, Binjie; Yao, Shasha; Song, Chunpeng

2014-01-01

45

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

NASA Technical Reports Server (NTRS)

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.

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

2000-01-01

46

Ferricyanide-mediated oxidation of ferrous nitrosylated sperm whale myoglobin involves the formation of the ferric nitrosylated intermediate.  

PubMed

Ferricyanide-mediated oxidation of ferrous oxygenated and carbonylated myoglobin (Mb(II)-O(2) and Mb(II)-CO, respectively) is limited by O(2) and CO dissociation, respectively, then the transient deoxygenated derivative (Mb(II)) is rapidly oxidized. Here, kinetics of ferricyanide-mediated oxidation of ferrous nitrosylated sperm whale myoblobin (Mb(II)-NO) is reported. Unlike for Mb(II)-O(2) and Mb(II)-CO, ferricyanide reacts with Mb(II)-NO forming first a transient ferric nitrosylated species (Mb(III)-NO), followed by the ()NO dissociation from Mb(III)-NO. Values of the second-order rate constant for ferricyanide-mediated oxidation of Mb(II)-NO (i.e., for the formation of the transient Mb(III)-NO species) and of the first-order rate constant for ()NO dissociation from Mb(III)-NO (i.e., for Mb(III) formation) are (1.3+/-0.2)x10(6)M(-1)s(-1) and 7.6+/-1.3s(-1), respectively, at pH 8.3 and 20.0 degrees C. Since ()NO dissociation from Mb(II)-NO is very slow, and (unlike O(2) and CO) ()NO is a ligand for both Mb(II) and Mb(III), Mb(II)-NO can be oxidized without requiring ()NO dissociation. PMID:17562327

Ascenzi, Paolo; Petrella, Giovanni; Coletta, Massimo

2007-08-10

47

Characterization of arsenopyrite oxidizing Thiobacillus. Tolerance to arsenite, arsenate, ferrous and ferric iron.  

PubMed

Two strains of Thiobacillus, T. ferrooxidans and T. thiooxidans, have been isolated from a bacterial inoculum cultivated during a one-year period in a 1001 continuous laboratory pilot for treatment of an arsenopyrite/pyrite concentrate. The optimum pH for the growth of both strains has been found to be between 1.7 and 2.5. Because of the high metal toxicity in bioleach pulps, the tolerance of T. ferrooxidans and T. thiooxidans with respect to iron and arsenic has been studied. The growth of both strains is inhibited with 10 g/l of ferric ion, 5 g/l of arsenite and 40 g/l of arsenate. 20 g/l of ferrous iron is toxic to T. ferrooxidans but 30 g/l is necessary to impede the growth of T. thiooxidans. PMID:2191624

Collinet, M N; Morin, D

1990-05-01

48

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

NASA Technical Reports Server (NTRS)

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.

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

2011-01-01

49

Osteoblast adhesion on nanophase ceramics  

Microsoft Academic Search

Osteoblast adhesion on nanophase alumina (Al2O3) and titania (TiO2) was investigated in vitro. Osteoblast adhesion to nanophase alumina and titania in the absence of serum from Dulbecco’s modified Eagle medium (DMEM) was significantly (P<0.01) less than osteoblast adhesion to alumina and titania in the presence of serum. In the presence of 10% fetal bovine serum in DMEM osteoblast adhesion on

Thomas J Webster; Richard W Siegel; Rena Bizios

1999-01-01

50

Effect of ferric oxide on the high-temperature removal of hydrogen sulfide over ZnO-Fe{sub 2}O{sub 3} mixed metal oxide sorbent  

SciTech Connect

The effect of ferric oxide on the removal of hydrogen sulfide over ZnO-Fe{sub 2}O{sub 3} mixed metal oxide sorbents and on the oxidative regeneration of sulfided sorbents was investigated. When ferric oxide was added to the zinc oxide, the reduction of ZnO was retarded by interaction of ZnO with ZnFe{sub 2}O{sub 4}. This interaction was confirmed by larger binding energies of Zn 2P{sub 3/2} and Zn 2P{sub 1/2}, identified by ESCA, of the ZnO-ZnFe{sub 2}O{sub 4} sorbent than those of ZnO. Zinc ferrite with a spinel structure yielded not only high H{sub 2}S removal capacity but also much SO{sub 2} generation. A linear increase of SO{sub 2} generation was confirmed up to 50 wt % Fe{sub 2}O{sub 3}. Resulting from the thermal decomposition of H{sub 2}S over metal sulfides, H{sub 2} generation increased with respect to Fe{sub 2}O{sub 3} according to a quadratic equation. Channeling, caused by sintering during sulfidation, made the flow path of the reactant change and thus pure ZnO sorbent and the sorbent containing 3 wt % Fe{sub 2}O did not sulfurate completely. Addition of Fe{sub 2}O{sub 3} prevented surface structural change like sintering of ZnO during sulfidation.

Lee, Y.S.; Kim, H.T.; Yoo, K.O. [Hanyang Univ., Seoul (Korea, Republic of). Dept. of Chemical Engineering

1995-04-01

51

Biodiesel Synthesis Catalyzed by Transition Metal Oxides: Ferric-Manganese Doped Tungstated/ Molybdena Nanoparticle Catalyst.  

PubMed

The solid acid Ferric-manganese doped tungstated/molybdena nananoparticle catalyst was prepared via impregnation reaction followed by calcination at 600? 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 200?; 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

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

2014-12-10

52

21 CFR 73.1298 - Ferric ammonium ferrocyanide.  

Code of Federal Regulations, 2011 CFR

...The color additive ferric ammonium ferrocyanide is the blue pigment obtained by oxidizing under acidic conditions with sodium...The oxidized product is filtered, washed, and dried. The pigment consists principally of ferric ammonium ferrocyanide...

2011-04-01

53

21 CFR 73.1298 - Ferric ammonium ferrocyanide.  

Code of Federal Regulations, 2012 CFR

...The color additive ferric ammonium ferrocyanide is the blue pigment obtained by oxidizing under acidic conditions with sodium...The oxidized product is filtered, washed, and dried. The pigment consists principally of ferric ammonium ferrocyanide...

2012-04-01

54

21 CFR 73.1298 - Ferric ammonium ferrocyanide.  

...The color additive ferric ammonium ferrocyanide is the blue pigment obtained by oxidizing under acidic conditions with sodium...The oxidized product is filtered, washed, and dried. The pigment consists principally of ferric ammonium ferrocyanide...

2014-04-01

55

21 CFR 73.1298 - Ferric ammonium ferrocyanide.  

Code of Federal Regulations, 2013 CFR

...The color additive ferric ammonium ferrocyanide is the blue pigment obtained by oxidizing under acidic conditions with sodium...The oxidized product is filtered, washed, and dried. The pigment consists principally of ferric ammonium ferrocyanide...

2013-04-01

56

21 CFR 73.1298 - Ferric ammonium ferrocyanide.  

Code of Federal Regulations, 2010 CFR

...The color additive ferric ammonium ferrocyanide is the blue pigment obtained by oxidizing under acidic conditions with sodium...The oxidized product is filtered, washed, and dried. The pigment consists principally of ferric ammonium ferrocyanide...

2010-04-01

57

Diallyl sulphide, a component of garlic, abrogates ferric nitrilotriacetate-induced oxidative stress and renal damage in rats.  

PubMed

Ferric nitrilotriacetate (Fe-NTA) induces tissue necrosis as a result of lipid peroxidation (LPO) and oxidative damage that leads to high incidence of renal carcinomas. The present study was undertaken to evaluate the effect of diallyl sulphide (DAS) against Fe-NTA-induced nephrotoxicity. A total of 30 healthy male rats were randomly divided into 5 groups of 6 rats each: (1) control, (2) DAS (200 mg kg(-1)), (3) Fe-NTA (9 g Fe kg(-1)), (4) DAS (100 mg kg(-1)) + Fe-NTA (9 mg Fe kg(-1)) and (5) DAS (200 mg kg(-1)) + Fe-NTA (9 mg Fe kg(-1)). Fe-NTA + DAS-treated groups were given DAS for a period of 1 week before Fe-NTA administration. The intraperitoneal administration of Fe-NTA enhanced blood urea nitrogen and creatinine levels with reduction in levels of antioxidant enzymes. However, significant restoration of depleted renal glutathione and its dependent enzymes (glutathione reductase and glutathione-S-transferase) was observed in DAS pretreated groups. DAS also attenuated Fe-NTA-induced increase in LPO, hydrogen peroxide generation and protein carbonyl formation (p < 0.05). The results indicate that DAS may be beneficial in ameliorating the Fe-NTA-induced renal oxidative damage in rats. PMID:24596035

Ansar, S; Iqbal, M; AlJameil, N

2014-12-01

58

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

PubMed

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

Chauhan, Nidhi; Pundir, C S

2014-11-15

59

Nuclear fuel elements made from nanophase materials  

DOEpatents

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.

Heubeck, N.B.

1998-09-08

60

Nuclear fuel elements made from nanophase materials  

DOEpatents

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.

Heubeck, Norman B. (Schenectady, NY)

1998-01-01

61

Assessment of the extent of oxidative stress induced by intravenous ferumoxytol, ferric carboxymaltose, iron sucrose and iron dextran in a nonclinical model.  

PubMed

Intravenous (i.v.) iron is associated with a risk of oxidative stress. The effects of ferumoxytol, a recently approved i.v. iron preparation, were compared with those of ferric carboxymaltose, low molecular weight iron dextran and iron sucrose in the liver, kidneys and heart of normal rats. In contrast to iron sucrose and ferric carboxymaltose, low molecular weight iron dextran and ferumoxytol caused renal and hepatic damage as demonstrated by proteinuria and increased liver enzyme levels. Higher levels of oxidative stress in these tissues were also indicated, by significantly higher levels of malondialdehyde, significantly increased antioxidant enzyme activities, and a significant reduction in the reduced to oxidized glutathione ratio. Inflammatory markers were also significantly higher with ferumoxytol and low molecular weight iron dextran rats than iron sucrose and ferric carboxymaltose. Polarographic analysis suggested that ferumoxytol contains a component with a more positive reduction potential, which may facilitate iron-catalyzed formation of reactive oxygen species and thus be responsible for the observed effects. Only low molecular weight iron dextran induced oxidative stress and inflammation in the heart. PMID:21899208

Toblli, Jorge E; Cao, Gabriel; Oliveri, Leda; Angerosa, Margarita

2011-01-01

62

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

PubMed Central

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

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

1979-01-01

63

Novel approach to zinc removal from circum-neutral mine waters using pelletised recovered hydrous ferric oxide.  

PubMed

Data are presented which evaluate the performance of a pilot-scale treatment system using pelletised hydrous ferric oxide (HFO; a waste stream from coal mine water treatment) as a high surface area sorbent for removing zinc (Zn) from a metal mine water discharge in the North Pennines Orefield, UK. Over a 10-month period the system removed Zn at mean area- and volume-adjusted removal rates of 3.7 and 8.1gm(-3)day(-1), respectively, with a mean treatment efficiency of 32% at a low mean residence time of 49min. There were seasonal effects in Zn removal owing to establishment and dieback of algae in the treatment tank. This led to increased Zn uptake in early summer months followed by slight Zn release upon algae senescence. In addition to these biosorptive processes, the principal sinks for Zn appear to be (1) sorption onto the HFO surface, and (2) precipitation with calcite-dominated secondary minerals. The latter were formed as a product of dissolution of portlandite in the cement binder and calcium recarbonation. Further optimisation of the HFO pelletisation process holds the possibility for providing a low-cost, low footprint treatment option for metal rich mine waters, in addition to a valuable after-use for recovered HFO from coal mine water treatment facilities. PMID:18583040

Mayes, William M; Potter, Hugh A B; Jarvis, Adam P

2009-02-15

64

Cellular and Biochemical Response of the Human Lung after Intrapulmonary Instillation of Ferric Oxide Particles  

Microsoft Academic Search

Bronchoalveolar lavage (BAL) was used to sample lung cells and biochemical components in the lung air spaces at various times from 1 to 91 d after intrapulmonary instillation of 2.6 m m-diameter iron oxide par- ticles in human subjects. The instillation of particles induced transient acute inflammation during the first day post instillation (PI), characterized by increased numbers of neutrophils

John C. Lay; William D. Bennett; Andrew J. Ghio; Philip A. Bromberg; Daniel L. Costa; Chong S. Kim; Hillel S. Koren; Robert B. Devlin

1999-01-01

65

Can ferric-superoxide act as a potential oxidant in P450(cam)? QM/MM investigation of hydroxylation, epoxidation, and sulfoxidation.  

PubMed

In view of recent reports of high reactivity of ferric-superoxide species in heme and nonheme systems (Morokuma et al. J. Am. Chem. Soc. 2010, 132, 11993-12005; Que et al. Inorg. Chem. 2010, 49, 3618-3628; Nam et al. J. Am. Chem. Soc. 2010, 132, 5958-5959; J. Am. Chem. Soc. 2010, 132, 10668-10670), we use herein combined quantum mechanics/molecular mechanics (QM/MM) methods to explore the potential reactivity of P450(cam) ferric-superoxide toward hydroxylation, epoxidation, and sulfoxidation. The calculations demonstrate that P450 ferric-superoxide is a sluggish oxidant compared with the high-valent oxoiron porphyrin cation-radical species. As such, unlike heme enzymes with a histidine axial ligand, the P450 superoxo species does not function as an oxidant in P450(cam). The origin of this different behavior of the superoxo species of P450 vis-a?-vis other heme enzymes like tryptophan 2, 3-dioxygenase (TDO) is traced to the ability of the latter superoxo species to make a stronger FeOO-X (X = H,C) bond and to stabilize the corresponding bond-activation transition states by resonance with charge-transfer configurations. By contrast, the negatively charged thiolate ligand in the P450 superoxo species minimizes the mixing of charge transfer configurations in the transition state and raises the reaction barrier. However, as we demonstrate, an external electric field oriented along the Fe-O axis with a direction pointing from Fe toward O will quench Cpd I formation by slowing the reduction of ferric-superoxide and will simultaneously lower the barriers for oxidation by the latter species, thereby enabling observation of superoxo chemistry in P450. Other options for nascent superoxo reactivity in P450 are discussed. PMID:21413763

Lai, Wenzhen; Shaik, Sason

2011-04-13

66

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

SciTech Connect

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.

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

2007-01-01

67

Dielectric Constant Enhancement of Epoxy Thermosets via Formation of Polyelectrolyte Nanophases.  

PubMed

Poly(ethylene oxide)-block-poly(sodium p-styrenesulfonate) (PEO-b-PSSNa) diblock copolymer was synthesized and then incorporated into epoxy to obtain the nanostructured epoxy thermosets containing polyelectrolyte nanophases. This PEO-b-PSSNa diblock copolymer was synthesized via the radical polymerization of p-styrenesulfonate mediated with 4-cyano-4-(thiobenzoylthio)valeric ester-terminated poly(ethylene oxide). The formation of polyelectrolyte (i.e., PSSNa) nanophases in epoxy followed a self-assembly mechanism. The precursors of epoxy acted as the selective solvent of the diblock copolymer, and thus, the self-assembled nanostructures were formed. The self-organized nanophases were fixed through the subsequent curing reaction. By means of transmission electron microscopy (TEM) and small-angle X-ray scattering (SAXS), the morphologies of the nanostructured epoxy thermosets containing PSSNa nanophases were investigated. In the glassy state, the epoxy matrixes were significantly reinforced by the spherical PSSNa nanodomains, as evidenced by dynamic mechanical analysis. The measurement of dielectric properties showed that, with the incorporation of PSSNa nanophases, the dielectric constants of the epoxy thermoset were significantly increased. Compared to the control epoxy, the dielectric loss of the nanostructured thermosets still remained at quite a low level, although the values of dielectric loss were slightly increased with inclusion of PSSNa nanophases. PMID:25482332

Cong, Houluo; Li, Jingang; Li, Lei; Zheng, Sixun

2014-12-18

68

Erythrocyte Hemolysis and Hemoglobin Oxidation Promote Ferric Chloride-induced Vascular Injury*S?  

PubMed Central

The release of redox-active iron and heme into the blood-stream is toxic to the vasculature, contributing to the development of vascular diseases. How iron induces endothelial injury remains ill defined. To investigate this, we developed a novel ex vivo perfusion chamber that enables direct analysis of the effects of FeCl3 on the vasculature. We demonstrate that FeCl3 treatment of isolated mouse aorta, perfused with whole blood, was associated with endothelial denudation, collagen exposure, and occlusive thrombus formation. Strikingly exposing vessels to FeCl3 alone, in the absence of perfused blood, was associated with only minor vascular injury. Whole blood fractionation studies revealed that FeCl3-induced vascular injury was red blood cell (erythrocyte)-dependent, requiring erythrocyte hemolysis and hemoglobin oxidation for endothelial denudation. Overall these studies define a unique mechanism of Fe3+-induced vascular injury that has implications for the understanding of FeCl3-dependent models of thrombosis and vascular dysfunction associated with severe intravascular hemolysis. PMID:19276082

Woollard, Kevin J.; Sturgeon, Sharelle; Chin-Dusting, Jaye P. F.; Salem, Hatem H.; Jackson, Shaun P.

2009-01-01

69

The nanophase iron mineral(s) in Mars soil  

NASA Technical Reports Server (NTRS)

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.

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

1993-01-01

70

Upper mantle oxidation state: Ferric iron contents of Iherzolite spinels by 57 Fe Mössbauer spectroscopy and resultant oxygen fugacities  

Microsoft Academic Search

The ferric iron contents of spinels from 30 spinel Iherzolite xenoliths have been measured by 57 Fe Mössbauer spectroscopy. The samples are widely dispersed in geographic and tectonic setting, coming from Southwest United States (San Carlos, Kilbourne Hole), Japan (Ichinomegata), Massif Central, France (Mont Brianēon) and Central Asia (Tariat Depression, Vitim Plateau). The total range of Fe 3 O 4

Bernard J. Wood; David Virgo

1989-01-01

71

Similarity of the Surface Reactivity of Hydrous Ferric Oxide and Hematite: Sorption and Redox of U(VI) and Fe(II)  

SciTech Connect

Hydrous Ferric Oxide (HFO) vs. Hematite--Thermodynamically distinctive bulk phases, but the surfaces could be similar due to hydration of the interface. Hypothesis--The surface of HFO is energetically similar to the surface of hematite. Objective--Compare the reactions of HFO and hematite with U(VI) and Fe(II). Experimental--The reactions of interests were (1) preparation of sub-micron hematite, (2) sorption of U(VI), and (3) redox of U(VI) and Fe(II) with HFO or hematite.

Je-Hun Jang; Dempsey, Brian A.; Burgos, William D.; Yeh, George; Roden, Eric

2004-03-17

72

Enhanced functions of osteoblasts on nanophase ceramics  

Microsoft Academic Search

Select functions of osteoblasts (bone-forming cells) on nanophase (materials with grain sizes less than 100nm) alumina, titania, and hydroxyapatite (HA) were investigated using in vitro cellular models. Compared to conventional ceramics, surface occupancy of osteoblast colonies was significantly less on all nanophase ceramics tested in the present study after 4 and 6 days of culture. Osteoblast proliferation was significantly greater

Thomas J Webster; Celaletdin Ergun; Robert H Doremus; Richard W Siegel; Rena Bizios

2000-01-01

73

Ferric Carboxymaltose Injection  

MedlinePLUS

Ferric carboxymaltose injection is used to treat iron-deficiency anemia (a lower than normal number of red blood cells ... stop working) who are not on dialysis. Ferric carboxymaltose injection is in a class of medications called ...

74

Nitric oxide acts downstream of auxin to trigger root ferric-chelate reductase activity in response to iron deficiency in Arabidopsis.  

PubMed

In response to iron (Fe) deficiency, dicots employ a reduction-based mechanism by inducing ferric-chelate reductase (FCR) at the root plasma membrane to enhance Fe uptake. However, the signal pathway leading to FCR induction is still unclear. Here, we found that the Fe-deficiency-induced increase of auxin and nitric oxide (NO) levels in wild-type Arabidopsis (Arabidopsis thaliana) was accompanied by up-regulation of root FCR activity and the expression of the basic helix-loop-helix transcription factor (FIT) and the ferric reduction oxidase 2 (FRO2) genes. This was further stimulated by application of exogenous auxin (?-naphthaleneacetic acid) or NO donor (S-nitrosoglutathione [GSNO]), but suppressed by either polar auxin transport inhibition with 1-naphthylphthalamic acid or NO scavenging with 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, tungstate, or N(?)-nitro-L-arginine methyl ester hydrochloride. On the other hand, the root FCR activity, NO level, and gene expression of FIT and FRO2 were higher in auxin-overproducing mutant yucca under Fe deficiency, which were sharply restrained by 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide treatment. The opposite response was observed in a basipetal auxin transport impaired mutant aux1-7, which was slightly rescued by exogenous GSNO application. Furthermore, Fe deficiency or ?-naphthaleneacetic acid application failed to induce Fe-deficiency responses in noa1 and nial nia2, two mutants with reduced NO synthesis, but root FCR activities in both mutants could be significantly elevated by GSNO. The inability to induce NO burst and FCR activity was further verified in a double mutant yucca noa1 with elevated auxin production and reduced NO accumulation. Therefore, we presented a novel signaling pathway where NO acts downstream of auxin to activate root FCR activity under Fe deficiency in Arabidopsis. PMID:20699398

Chen, Wei Wei; Yang, Jian Li; Qin, Cheng; Jin, Chong Wei; Mo, Ji Hao; Ye, Ting; Zheng, Shao Jian

2010-10-01

75

Nitric Oxide Acts Downstream of Auxin to Trigger Root Ferric-Chelate Reductase Activity in Response to Iron Deficiency in Arabidopsis1[C][W][OA  

PubMed Central

In response to iron (Fe) deficiency, dicots employ a reduction-based mechanism by inducing ferric-chelate reductase (FCR) at the root plasma membrane to enhance Fe uptake. However, the signal pathway leading to FCR induction is still unclear. Here, we found that the Fe-deficiency-induced increase of auxin and nitric oxide (NO) levels in wild-type Arabidopsis (Arabidopsis thaliana) was accompanied by up-regulation of root FCR activity and the expression of the basic helix-loop-helix transcription factor (FIT) and the ferric reduction oxidase 2 (FRO2) genes. This was further stimulated by application of exogenous auxin (?-naphthaleneacetic acid) or NO donor (S-nitrosoglutathione [GSNO]), but suppressed by either polar auxin transport inhibition with 1-naphthylphthalamic acid or NO scavenging with 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, tungstate, or N?-nitro-l-arginine methyl ester hydrochloride. On the other hand, the root FCR activity, NO level, and gene expression of FIT and FRO2 were higher in auxin-overproducing mutant yucca under Fe deficiency, which were sharply restrained by 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide treatment. The opposite response was observed in a basipetal auxin transport impaired mutant aux1-7, which was slightly rescued by exogenous GSNO application. Furthermore, Fe deficiency or ?-naphthaleneacetic acid application failed to induce Fe-deficiency responses in noa1 and nial nia2, two mutants with reduced NO synthesis, but root FCR activities in both mutants could be significantly elevated by GSNO. The inability to induce NO burst and FCR activity was further verified in a double mutant yucca noa1 with elevated auxin production and reduced NO accumulation. Therefore, we presented a novel signaling pathway where NO acts downstream of auxin to activate root FCR activity under Fe deficiency in Arabidopsis. PMID:20699398

Chen, Wei Wei; Yang, Jian Li; Qin, Cheng; Jin, Chong Wei; Mo, Ji Hao; Ye, Ting; Zheng, Shao Jian

2010-01-01

76

Center for Nanophase Materials Sciences Strategic Plan  

E-print Network

Center for Nanophase Materials Sciences Strategic Plan 2015Ā­2019 October 2014 #12;#12;iii CONTENTS ................................................................... 5 3. Integration into ORNL Missions: Neutron Sciences, Materials by Design, Imaging ................ 6 The Link to Neutron Sciences

77

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

PubMed

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

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

2014-08-01

78

Synthesis and characterization of nanophase zirconia : reverse micelle method and neutron scattering study.  

SciTech Connect

Zirconia is an important transition-metal oxide for catalytic applications. It has been widely used in automotive exhaust treatment, methanol synthesis, isomerization, alkylation, etc. [1]. Nanophase materials have unique physiochemical properties such as quantum size effects, high surface area, uniform morphology, narrow size distribution, and improvement of sintering rates[2]. Microemulsion method provides the means for controlling the microenvironment under which specific chemical reactions may occur in favoring the formation of homogeneous, nanometer-size particles. In this paper, we report the synthesis of nanophase zirconia and the characterization of the microemulsions as well as the powders by small- and wide-angle neutron scattering techniques.

Li, X.

1998-11-23

79

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

SciTech Connect

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), ?-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, ?-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 ?-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.

Koretsky, Carla [Western Michigan University] [Western Michigan University

2013-11-29

80

Ferrous Iron and Sulfur Oxidation and Ferric Iron Reduction Activities of Thiobacillus ferrooxidans Are Affected by Growth on Ferrous Iron, Sulfur, or a Sulfide Ore  

PubMed Central

Eight strains of Thiobacillus ferrooxidans (laboratory strains Tf-1 [= ATCC 13661] and Tf-2 [= ATCC 19859] and mine isolates SM-1, SM-2, SM-3, SM-4, SM-5, and SM-8) and three strains of Thiobacillus thiooxidans (laboratory strain Tt [= ATCC 8085] and mine isolates SM-6 and SM-7) were grown on ferrous iron (Fe2+), elemental sulfur (S0), or sulfide ore (Fe, Cu, and Zn). The cells were studied for their aerobic Fe2+ - and S0-oxidizing activities (O2 consumption) and anaerobic S0-oxidizing activity with ferric iron (Fe3+) (Fe2+ formation). Fe2+-grown T. ferrooxidans cells oxidized S0 aerobically at a rate of 2 to 4% of the Fe2+ oxidation rate. The rate of anaerobic S0 oxidation with Fe3+ was equal to the aerobic oxidation rate in SM-1, SM-3, SM-4, and SM-5, but was only one-half or less that in Tf-1, Tf-2, SM-2, and SM-8. Transition from growth on Fe2+ to that on S0 produced cells with relatively undiminished Fe2+ oxidation activities and increased S0 oxidation (both aerobic and anaerobic) activities in Tf-2, SM-4, and SM-5, whereas it produced cells with dramatically reduced Fe2+ oxidation and anaerobic S0 oxidation activities in Tf-1, SM-1, SM-2, SM-3, and SM-8. Growth on ore 1 of metal-leaching Fe2+-grown strains and on ore 2 of all Fe2+-grown strains resulted in very high yields of cells with high Fe2+ and S0 oxidation (both aerobic and anaerobic) activities with similar ratios of various activities. Sulfur-grown Tf-2, SM-1, SM-4, SM-6, SM-7, and SM-8 cultures leached metals from ore 3, and Tf-2 and SM-4 cells recovered showed activity ratios similar to those of other ore-grown cells. It is concluded that all the T. ferrooxidans strains studied have the ability to produce cells with Fe2+ and S0 oxidation and Fe3+ reduction activities, but their levels are influenced by growth substrates and strain differences. PMID:16348205

Suzuki, Isamu; Takeuchi, Travis L.; Yuthasastrakosol, Trin D.; Oh, Jae Key

1990-01-01

81

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

NASA Technical Reports Server (NTRS)

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.

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

1990-01-01

82

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

NASA Technical Reports Server (NTRS)

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.

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

2003-01-01

83

Do grain boundaries in nanophase metals slide?  

SciTech Connect

Nanophase metallic materials show a maximum in strength as grain size decreases to the nano scale, indicating a break down of the Hall-Petch relation. Grain boundary sliding, as a possible accommodation mechanisms, is often the picture that explain computer simulations results and real experiments. In a recent paper, Bringa et al. Science 309, 1838 (2005), we report on the observation of an ultra-hard behavior in nanophase Cu under shock loading, explained in terms of a reduction of grain boundary sliding under the influence of the shock pressure. In this work we perform a detailed study of the effects of hydrostatic pressure on nanophase Cu plasticity and find that it can be understood in terms of pressure dependent grain boundary sliding controlled by a Mohr-Coulomb law.

Bringa, E M; Leveugle, E; Caro, A

2006-10-27

84

Iron-Oxidizing Bacteria Are Associated with Ferric Hydroxide Precipitates (Fe-Plaque) on the Roots of Wetland Plants  

PubMed Central

The presence of Fe-oxidizing bacteria in the rhizosphere of four different species of wetland plants was investigated in a diverse wetland environment that had Fe(II) concentrations ranging from tens to hundreds of micromoles per liter and a pH range of 3.5 to 6.8. Enrichments for neutrophilic, putatively lithotrophic Fe-oxidizing bacteria were successful on roots from all four species; acidophilic Fe-oxidizing bacteria were enriched only on roots from plants whose root systems were exposed to soil solutions with a pH of <4. In Sagittaria australis there was a positive correlation (P < 0.01) between cell numbers and the total amount of Fe present; the same correlation was not found for Leersia oryzoides. These results present the first evidence for culturable Fe-oxidizing bacteria associated with Fe-plaque in the rhizosphere. PMID:10347074

Emerson, David; Weiss, Johanna V.; Megonigal, J. Patrick

1999-01-01

85

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

PubMed

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

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

2014-02-01

86

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)

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.

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

2014-01-01

87

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

SciTech Connect

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.

Fagal, Gehan A. [Physical Chemistry Department, National Research Center, Dokki, Cairo (Egypt)] [Physical Chemistry Department, National Research Center, Dokki, Cairo (Egypt); Badawy, Abdelrahman A. [Physical Chemistry Department, Center of Excellence for advanced Science, Renewable Energy Group, National Research Center, Dokki, Cairo (Egypt)] [Physical Chemistry Department, Center of Excellence for advanced Science, Renewable Energy Group, National Research Center, Dokki, Cairo (Egypt); Hassan, Neven A. [Physical Chemistry Department, National Research Center, Dokki, Cairo (Egypt)] [Physical Chemistry Department, National Research Center, Dokki, Cairo (Egypt); El-Shobaky, Gamil A., E-mail: gamil_elshobaky@yahoo.com [Physical Chemistry Department, National Research Center, Dokki, Cairo (Egypt)

2012-10-15

88

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)

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.

Bligh, Mark W.; Waite, T. David

2011-12-01

89

Platinum-Catalyzed Oxidations of Organic Compounds by Ferric Sulfate: Use of a Redox Fuel Cell to Mediate Complete Oxidation of Ethylene Glycol by Dioxygen at 80°C  

Microsoft Academic Search

A number of alcohols, aldehydes, and carboxylic acids were oxidized under mild conditions (60–80°C, 3MH2SO4in water) by Fe(III) using a catalytic amount of Pt black to generate Fe(II) and protons. The extent of oxidation depended on the structures of the organic reductant and on reaction conditions. A redox fuel cell that catalyzed the complete oxidation of ethylene glycol by dioxygen

Christopher B. Gorman; Steven H. Bergens; George M. Whitesides

1996-01-01

90

Synthesis, properties, and applications of nanophase materials  

SciTech Connect

Work on the synthesis, properties, and applications of nanophase materials has developed rapidly during the past decade. A wide variety of methods now exist for their production, including several plasma-based processes. The possibilities for engineering new materials with unique or improved properties for a number of applications is now evident from the extant research results. A brief review is presented here along with some examples of useful application areas and some thoughts for the future of this field.

Siegel, R.W. [Max-Planck-Institut fuer Mikrostrukturphysik, Halle/Saale (Germany)]|[Argonne National Lab., IL (United States)

1995-04-01

91

Ferric Tourmaline from Mexico.  

PubMed

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

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

1964-04-01

92

21 CFR 73.1299 - Ferric ferrocyanide.  

...1299 Ferric ferrocyanide. (a) Identity. (1) The color additive ferric ferrocyanide is a ferric hexacyanoferrate pigment characterized by the structual formula Fe4 [Fe(CN)6 ]3 ·XH2 O, which may contain small amounts of ferric...

2014-04-01

93

21 CFR 73.1299 - Ferric ferrocyanide.  

Code of Federal Regulations, 2012 CFR

...1299 Ferric ferrocyanide. (a) Identity. (1) The color additive ferric ferrocyanide is a ferric hexacyanoferrate pigment characterized by the structual formula Fe4 [Fe(CN)6 ]3 ·XH2 O, which may contain small amounts of ferric...

2012-04-01

94

Ferric oxides in East Candor Chasma, Valles Marineris (Mars) inferred from analysis of OMEGA\\/Mars Express data: Identification and geological interpretation  

Microsoft Academic Search

The mineralogical composition of the Martian surface is constrained by analyzing the data of the OMEGA visible and near infrared imaging spectrometer onboard Mars Express. Ferric signatures had previously been reported in Valles Marineris, Margaritifer Terra, and Terra Meridiani. Here we use three independent data reduction methods (Spectral Angle Mapper, a modified Spectral Mixture Analysis and Modified Gaussian Model) to

Laetitia Le Deit; Stéphane Le Mouélic; Olivier Bourgeois; Jean-Philippe Combe; Daniel Mčge; Christophe Sotin; Aline Gendrin; Ernst Hauber; Nicolas Mangold; Jean-Pierre Bibring

2008-01-01

95

Transcriptional and Proteomic Analysis of a Ferric Uptake Regulator (Fur) Mutant of Shewanella oneidensis: Possible Involvement of Fur in Energy Metabolism, Transcriptional Regulation, and Oxidative Stress  

PubMed Central

The iron-directed, coordinate regulation of genes depends on the fur (ferric uptake regulator) gene product, which acts as an iron-responsive, transcriptional repressor protein. To investigate the biological function of a fur homolog in the dissimilatory metal-reducing bacterium Shewanella oneidensis MR-1, a fur knockout strain (FUR1) was generated by suicide plasmid integration into this gene and characterized using phenotype assays, DNA microarrays containing 691 arrayed genes, and two-dimensional polyacrylamide gel electrophoresis. Physiological studies indicated that FUR1 was similar to the wild-type strain when they were compared for anaerobic growth and reduction of various electron acceptors. Transcription profiling, however, revealed that genes with predicted functions in electron transport, energy metabolism, transcriptional regulation, and oxidative stress protection were either repressed (ccoNQ, etrA, cytochrome b and c maturation-encoding genes, qor, yiaY, sodB, rpoH, phoB, and chvI) or induced (yggW, pdhC, prpC, aceE, fdhD, and ppc) in the fur mutant. Disruption of fur also resulted in derepression of genes (hxuC, alcC, fhuA, hemR, irgA, and ompW) putatively involved in iron uptake. This agreed with the finding that the fur mutant produced threefold-higher levels of siderophore than the wild-type strain under conditions of sufficient iron. Analysis of a subset of the FUR1 proteome (i.e., primarily soluble cytoplasmic and periplasmic proteins) indicated that 11 major protein species reproducibly showed significant (P < 0.05) differences in abundance relative to the wild type. Protein identification using mass spectrometry indicated that the expression of two of these proteins (SodB and AlcC) correlated with the microarray data. These results suggest a possible regulatory role of S. oneidensis MR-1 Fur in energy metabolism that extends the traditional model of Fur as a negative regulator of iron acquisition systems. PMID:11823232

Thompson, Dorothea K.; Beliaev, Alexander S.; Giometti, Carol S.; Tollaksen, Sandra L.; Khare, Tripti; Lies, Douglas P.; Nealson, Kenneth H.; Lim, Hanjo; Yates III, John; Brandt, Craig C.; Tiedje, James M.; Zhou, Jizhong

2002-01-01

96

Influence of the dose levels of cocarcinogen ferric oxide on the metabolism of benzo[a]pyrene by pulmonary alveolar macorphages in suspension culture  

SciTech Connect

The concurrent administration of a cocarcinogenic carrier particle such as ferric oxide (Fe[sub 2]O[sub 3]) and the polycyclic aromatic hydrocarbon lung carcinogen benzo[a]pyrene (BaP) results in a decreased latency and an increased incidence in the production of lung tumors in hamsters compared to the administration of BaP alone. The pulmonary alveolar macrophage (AM), the primary lung defense cell, has been shown to endoctyze BaP, metabolize BaP to a more biologically active form, and then release metabolites. Therefore, a study was undertaken to determine in a dose-response manner the effect of AM phagocysosis of a carrier particle (Fe[sub 2]O[sub 3]) on the metabolism of a carcinogen (BaP) and on the production of reactive oxygen. The AM were lavaged from hamsters and cultured in suspension (2.5 [times] 10[sup 6] cells/vial) with bAp (62.5 NMOL, [sup 14]c labeled) alone or adsorbed onto 0.5, 1.0, or 2.0 mg Fe[sub 2]O[sub 3] in the presence of cytochrome c. Following separate ethyl acetate extractions of the AM and medium, the metabolites were isolated by high-performance liquid chromatography (HPLC) and quantified by liquid scintillation spectrometry. The production of superoxide anions was monitored by the reduction of cyctochrome c. Concurrent exposure of AM to BaP-coated Fe[sub 2]O[sub 3] resulted in a significant increase in the amount of BaP metabolites and superoxide anions produced with dose of Fe[sub 2]O[sub 3]. The following metabolites and superoxide anions produced with dose of Fe[sub e]O[sub 3]. The following metabolites were identified in both the medium and the AM: 9,10-dihydrodiol, 7,8-dihydrodiol, 4,5-dihydrodiol, 9-hydroxy, 3-hydroxy, and 3,6 quinone. 44 refs., 5 figs., 2 tabs.

Greife, A.L. (National Institute for Occupational Safety and Health, Cincinatti, OH (United States)); Warshawsky, D. (Univ. of Cincinatti Medical Center, OH (United States))

1993-01-01

97

Transcriptional and Proteomic Analysis of a Ferric Uptake Regulator (Fur) Mutant of Shewanella oneidensis: Possible Involvement of Fur in Energy Metabolism, Transcriptional Regulation, and Oxidative Stress  

Microsoft Academic Search

The iron-directed, coordinate regulation of genes depends on the fur (ferric uptake regulator) gene product, which acts as an iron-responsive, transcriptional repressor protein. To investigate the biological function of a fur homolog in the dissimilatory metal-reducing bacterium Shewanella oneidensis MR-1, a fur knockout strain (FUR1) was generated by suicide plasmid integration into this gene and characterized using phenotype assays, DNA

Dorothea K. Thompson; Alexander S. Beliaev; Carol S. Giometti; Sandra L. Tollaksen; Tripti Khare; Douglas P. Lies; Kenneth H. Nealson; Hanjo Lim; John Yates; Craig C. Brandt; James M. Tiedje; Jizhong Zhou

2002-01-01

98

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

SciTech Connect

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.

Tushar K Ghosh

2008-10-13

99

Specific proteins mediate enhanced osteoblast adhesion on nanophase ceramics.  

PubMed

Osteoblast, fibroblast, and endothelial cell adhesion on nanophase (that is, materials with grain sizes less than 100 nm) alumina, titania, and hydroxyapatite (HA) was investigated using in vitro cellular models. Osteoblast adhesion was significantly (p < 0.01) greater after 4 h on nanophase alumina, titania, and HA than it was on conventional formulations of the same ceramics. In contrast, compared to conventional alumina, titania, and HA, after 4 h fibroblast adhesion was significantly (p < 0.01) less on nanophase ceramics. Examination of the underlying mechanism(s) of cell adhesion on nanophase ceramics revealed that these ceramics adsorbed significantly (p < 0.01) greater quantities of vitronectin, which, subsequently, may have contributed to the observed select enhanced adhesion of osteoblasts. Select enhanced osteoblast adhesion was independent of surface chemistry and material phase but was dependent on the surface topography (specifically on grain and pore size) of nanophase ceramics. The capability of synthesizing and processing nanomaterials with tailored (through, for example, specific grain and pore size) structures and topographies to control select subsequent cell functions provides the possibility of designing the novel proactive biomaterials (that is, materials that elicit specific, timely, and desirable responses from surrounding cells and tissues) necessary for improved implant efficacy. PMID:10880091

Webster, T J; Ergun, C; Doremus, R H; Siegel, R W; Bizios, R

2000-09-01

100

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

NASA Technical Reports Server (NTRS)

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.

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

1995-01-01

101

Superhard nanophase cutter materials for rock drilling applications  

SciTech Connect

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.

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

2000-06-23

102

Structure and properties of nanophase TiO/sub 2/  

SciTech Connect

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.

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

1987-07-01

103

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...

104

21 CFR 582.5304 - Ferric pyrophosphate.  

... ANIMAL 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...

2014-04-01

105

21 CFR 582.5301 - Ferric phosphate.  

... ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5301 Ferric phosphate. (a) Product. Ferric phosphate. (b) Conditions of use....

2014-04-01

106

21 CFR 582.5301 - Ferric phosphate.  

Code of Federal Regulations, 2012 CFR

... ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5301 Ferric phosphate. (a) Product. Ferric phosphate. (b) Conditions of use....

2012-04-01

107

21 CFR 582.5301 - Ferric phosphate.  

Code of Federal Regulations, 2013 CFR

... ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5301 Ferric phosphate. (a) Product. Ferric phosphate. (b) Conditions of use....

2013-04-01

108

21 CFR 582.5301 - Ferric phosphate.  

Code of Federal Regulations, 2011 CFR

... ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5301 Ferric phosphate. (a) Product. Ferric phosphate. (b) Conditions of use....

2011-04-01

109

Adverse reactions of ferric carboxymaltose.  

PubMed

The author reports a 55-year-old female diagnosed of chronic kidney disease grade-5 with associated co-morbidities like type 2 diabetes mellitus, diabetic retinopathy and hypothyroidism was admitted for arteriovenous fistula construction. She was started on ferric carboxymaltose for the treatment of anaemia. She was given a test dose before administering the drug intravenously and she did not develop any reaction. The drug ferric carboxymaltose was then administered over a period of one hour. About half an hour after drug administration, the patient developed breathlessness and myalgia. After half hour of the above episode of breathlessness and myalgia she also developed vomiting (one episode). Patient was managed with oxygen therapy, IV fluids and other drugs like corticosteroids, phenaramine maleate and nalbuphine which controlled the above symptoms. PMID:25478369

Thanusubramanian, Harish; Patil, Navin; Shenoy, Smita; Bairy, K L; Sarma, Yashdeep

2014-10-01

110

Adverse Reactions of Ferric Carboxymaltose  

PubMed Central

The author reports a 55-year-old female diagnosed of chronic kidney disease grade-5 with associated co-morbidities like type 2 diabetes mellitus, diabetic retinopathy and hypothyroidism was admitted for arteriovenous fistula construction. She was started on ferric carboxymaltose for the treatment of anaemia. She was given a test dose before administering the drug intravenously and she did not develop any reaction. The drug ferric carboxymaltose was then administered over a period of one hour. About half an hour after drug administration, the patient developed breathlessness and myalgia. After half hour of the above episode of breathlessness and myalgia she also developed vomiting (one episode). Patient was managed with oxygen therapy, IV fluids and other drugs like corticosteroids, phenaramine maleate and nalbuphine which controlled the above symptoms. PMID:25478369

Patil, Navin; Shenoy, Smita; Bairy, K L; Sarma, Yashdeep

2014-01-01

111

Nanophase Nickel-Zirconium Alloys for Fuel Cells  

NASA Technical Reports Server (NTRS)

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.

Narayanan, Sekharipuram; Whitacre, jay; Valdez, Thomas

2008-01-01

112

Bis-histidyl Ferric Adducts in Tetrameric Haemoglobins  

Microsoft Academic Search

In the last decade crystallographic evidence for endogenous coordination at the sixth coordination site of the heme iron has\\u000a been reported for monomeric haemoglobins (Hbs) in both the ferrous (haemochrome) and ferric (haemichrome) oxidation state.\\u000a Usually, the sixth ligand is provided by the imi-dazole side chain of a His, the only putative ligand normally present in\\u000a the distal site of

Alessandro Vergara; Cinzia Verde; Guido Prisco; Lelio Mazzarella

113

Method of treating inflammatory diseases using a radiolabeled ferric hydroxide calloid  

DOEpatents

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.

Atcher, Robert W. (Chicago, IL); Hines, John J. (Glen Ellyn, IL)

1992-01-01

114

Synthesis and Manipulation of Nanophase Magnetic Materials  

Microsoft Academic Search

Synthesis of various types of inorganic materials, namely metals, ternary metal oxides (ferrites), cadmium sulfide (doped with Mn) and alkaline trifluoromanganates, in their nanocrystalline state is performed in aqueous solutions. Restricting conditions for crystal growth were provided using reverse micelle water-in-oil microemulsions technique. The obtained materials have been characterized using electron microscopy TEM imaging, X-ray diffractometry and SQUID magnetometry. nanoparticles

J. Sims; A. Kumbhar; J. Lin; F. Agnoli; E. Carpenter; C. Sangregorio; C. Frommen; V. Kolesnichenko; C. J. OCONNOR

2003-01-01

115

Ferric sulfate montmorillonites as Mars soil analogs  

NASA Technical Reports Server (NTRS)

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.

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

1993-01-01

116

Platinum-catalyzed oxidations of organic compounds by ferric sulfate: Use of a redox fuel cell to mediate complete oxidation of ethylene glycol by dioxygen at 80{degrees}C  

SciTech Connect

A number of alcohols, aldehydes, and carboxylic acids were oxidized under mild conditions (60-80{degrees}C, 3 M H{sub 2}SO{sub 4} in water) by Fe(III) using a catalytic amount of Pt black to generate Fe(II) and protons. The extent of oxidation depended on the structures of the organic reductant and on reaction conditions. A redox fuel cell that catalyzed the complete oxidation of ethylene glycol by dioxygen at 80{degrees}C was assembled. Fe(II) generated by oxidation of ethylene glycol was reoxidized to Fe(III) at the anode of the cell. A V(V)/V(IV)/HNO{sub 3}/O{sub 2} redox system was used to catalyze the electrochemical reduction of dioxygen. Both the anode and cathode consisted of WDF graphite felt, the surface of which had been oxidized by boiling concentrated nitric acid for 15 min. A maximum power density of 9.9 mW/cm{sup 3} of graphite felt was obtained at a cell voltage of 197 mV. 19 refs., 3 figs., 1 tab.

Gorman, C.B.; Bergens, S.H.; Whitesides, G.M. [Harvard Univ., Cambridge, MA (United States)] [Harvard Univ., Cambridge, MA (United States)

1996-01-01

117

Selection of Leptospirillum ferrooxidans SRPCBL and development for enhanced ferric regeneration in stirred tank and airlift column reactor.  

PubMed

Presence of Leptospirillum ferrooxidans plays significant role in ferric sulphate generation during bioleaching process. Thus, an attempt was made to select L. ferrooxidans from the polymetallic concentrate leachate and further developed it for enhanced ferric iron regeneration from the leachate in shake flask, stirred tank and column reactor. When ferric to ferrous iron ratio in the shake flask reached to 20:1, L. ferrooxidans out competed Acidithiobacillus ferrooxidans and accounted for more than 99% of the total population. The isolate was confirmed by 16S rRNA genes sequence analysis and named as L. ferrooxidans SRPCBL. When the culture was exposure to UV dose and the oxidation-reduction potential of the inoculation medium was adjusted to 40 0mV by ferrous:ferric iron ratio, the IOR reached to as high as 1.2 g/L/h in shake flask, even with initial ferrous iron concentration of 200 g/L. The chalcopyrite concentrate leachate containing 12.8, 15.7, and 42.0 g/L ferrous iron, ferric iron and copper, respectively was studied for ferric iron regeneration with the developed polymetallic resistant L. ferrooxidans SRPCBL in stirred tank and a developed biofilm airlift column, the highest IOR achieved were 2.20 g/L/h and 3.1 g/L/h, respectively, with ferrous oxidation efficiency of 98%. The ferric regeneration ability of the developed isolate from the leachate proves useful for a two-stage metal extraction process. PMID:18325759

Dave, Shailesh R

2008-11-01

118

21 CFR 73.2299 - Ferric ferrocyanide.  

Code of Federal Regulations, 2010 CFR

...GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION...specifications. The color additive ferric ferrocyanide shall...amounts consistent with good manufacturing practice. (c) Labeling. The color additive and any mixture...

2010-04-01

119

21 CFR 73.2299 - Ferric ferrocyanide.  

Code of Federal Regulations, 2011 CFR

...GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION...specifications. The color additive ferric ferrocyanide shall...amounts consistent with good manufacturing practice. (c) Labeling. The color additive and any mixture...

2011-04-01

120

21 CFR 73.2299 - Ferric ferrocyanide.  

Code of Federal Regulations, 2012 CFR

...GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION...specifications. The color additive ferric ferrocyanide shall...amounts consistent with good manufacturing practice. (c) Labeling. The color additive and any mixture...

2012-04-01

121

21 CFR 73.2299 - Ferric ferrocyanide.  

Code of Federal Regulations, 2013 CFR

...GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION...specifications. The color additive ferric ferrocyanide shall...amounts consistent with good manufacturing practice. (c) Labeling. The color additive and any mixture...

2013-04-01

122

21 CFR 73.2299 - Ferric ferrocyanide.  

...GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION...specifications. The color additive ferric ferrocyanide shall...amounts consistent with good manufacturing practice. (c) Labeling. The color additive and any mixture...

2014-04-01

123

Suppression of methane emission from rice paddies by ferric iron fertilization  

Microsoft Academic Search

Rice microcosms incubated in the greenhouse showed that methane emission was reduced after fertilization of the soil with ferric iron oxide–ferrihydrite. The total methane emission during the vegetation period of rice was reduced by 43% and 84%, with the addition of 15 and 30 g of ferrihydrite per kg of soil, respectively. Growth of the rice plants was reduced during

Udo Jäckel; Sylvia Schnell

2000-01-01

124

Ferric chloride graphite intercalation compounds prepared from graphite fluoride  

NASA Technical Reports Server (NTRS)

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.

Hung, Ching-Cheh

1994-01-01

125

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

PubMed Central

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

Kosman, Daniel J.

2012-01-01

126

Statistics of sub-Poissonian nucleation in a nanophase  

NASA Astrophysics Data System (ADS)

We develop a fully analytical calculation of the sub-Poissonian statistics resulting from the temporal anticorrelation of the nucleation events in a supersaturated nanophase, such as occurs in particular during vapor-liquid-solid growth of nanowires [F. Glas, J. C. Harmand, and G. Patriarche, Phys. Rev. Lett. 104, 135501 (2010), 10.1103/PhysRevLett.104.135501]. The sequence of nucleation events is modeled as a stochastic Markov process. The deviation from Poisson statistics is quantified by a single parameter ?, namely the ratio of the nucleation probabilities immediately after and before nucleation. We first determine self-consistently, by using q-calculus, the densities of probability of the nucleation probability, both when nucleation occurs and at an arbitrary instant. We then derive the probability for having a given number of nucleations in any given time interval. The distribution of these probabilities shows a marked narrowing with respect to Poisson statistics, in agreement with our previous experiments. We calculate explicitly the standard deviation of this distribution, which quickly saturates as the length of the time interval increases. Finally, we compute the distribution of the waiting times between nucleations. We discuss how the computed quantities vary with parameter ?. The results are in complete agreement with our numerical simulations. Somewhat surprisingly, a marked narrowing of the distribution of the numbers of nucleations occurring in fixed time intervals appears as fully compatible with a very broad distribution of waiting times.

Glas, Frank

2014-09-01

127

Superoxide dismutase and Fenton chemistry. Reaction of ferric-EDTA complex and ferric-bipyridyl complex with hydrogen peroxide without the apparent formation of iron(II).  

PubMed

A ferric-EDTA complex, prepared directly from FeCl3 or from an oxidized ferrous salt, reacts with H2O2 to form hydroxyl radicals (.OH), which degrade deoxyribose and benzoate with the release of thiobarbituric acid-reactive material, hydroxylate benzoate to form fluorescent dihydroxy products and react with 5,5-dimethylpyrrolidine N-oxide (DMPO) to form a DMPO-OH adduct. Degradation of deoxyribose and benzoate and the hydroxylation of benzoate are substantially inhibited by superoxide dismutase and .OH-radical scavengers such as formate, thiourea and mannitol. Inhibition by the enzyme superoxide dismutase implies that the reduction of the ferric-EDTA complex for participation in the Fenton reaction is superoxide-(O2.-)-dependent, and not H2O2-dependent as frequently implied. When ferric-bipyridyl complex at a molar ratio of 1:4 is substituted for ferric-EDTA complex (molar ratio 1:1) and the same experiments are conducted, oxidant damage is low and deoxyribose and benzoate degradation were poorly if at all inhibited by superoxide dismutase and .OH-radical scavengers. Benzoate hydroxylation, although weak, was, however, more effectively inhibited by superoxide dismutase and .OH-radical scavengers, implicating some role for .OH. The iron-bipyridyl complex had available iron-binding capacity and therefore would not allow iron to remain bound to buffer or detector molecules. Most .OH radicals produced by the iron-bipyridyl complex and H2O2 are likely to damage the bipyridyl molecules first, with few reacting in free solution with the detector molecules. Deoxyribose and benzoate degradation appeared to be mediated by an oxidant species not typical of .OH, and species such as the ferryl ion-bipyridyl complex may have contributed to the damage observed. PMID:2165392

Gutteridge, J M; Maidt, L; Poyer, L

1990-07-01

128

21 CFR 184.1304 - Ferric pyrophosphate.  

Code of Federal Regulations, 2010 CFR

...iron (III) pyrophosphate, Fe4 (P207 )3 ·xH2 O, CAS Reg. No. 10058-44-3) is a tan or yellowish white colorless powder. It is prepared by reacting sodium pyrophosphate with ferric citrate. (b) The ingredient meets...

2010-04-01

129

Design, synthesis, and evaluation of nanophase ceramics for orthopaedic/dental applications  

NASA Astrophysics Data System (ADS)

Clinical complications with conventional orthopaedic/dental implant devices are often due to insufficient bonding to juxtaposed bone; osseointegration provides mechanical stability to prostheses in situ , minimizes motion induced damage to surrounding tissues and is crucial to the clinical success of orthopaedic/dental implants. Ceramics have long been appreciated for their biocompatibility with bone cells and tissue, but, poor mechanical properties (such as ductility) have limited their wide use as orthopaedic/dental implants. The objective of the present in vitro study was to investigate, for the first time, various properties of nanophase (that is, novel material formulations with grain and pore sizes less than 100 nm) ceramics pertinent to orthopaedic/dental applications. Compared to conventional (that is, grain sizes greater than 100 nm) formulations of the same material, nanophase ceramics possess attractive mechanical and cytocompatibility properties. Specifically, nanophase ceramics demonstrated bending properties on the same order of magnitude as physiological bone; such properties are highly desirable for materials used as bone implants. Most important, the functions (such as adhesion, proliferation, synthesis of alkaline phosphatase, and deposition of calcium-containing mineral) of osteoblasts (the bone-forming cells) were selectively and significantly enhanced on nanophase ceramics. These results are most remarkable when contrasted to the observed decreased adhesion of fibroblasts (cells that contribute to fibrous encapsulation and callus formation events that lead to implant loosening and failure) on the nanophase alumina, titania, and hydroxyapatite tested. Investigation of the mechanism(s) of the observed, select, enhanced osteoblast adhesion (a crucial prerequisite for subsequent, anchorage-dependent-cell function) on all ceramic formulations tested in the present study revealed that the concentration, conformation, and bioactivity of vitronectin were important parameters mediating osteoblast adhesion exclusively on nanoceramics. Conformation of vitronectin that exposed epitopes (such as integrin-binding and heparan sulfate-binding sites) necessary for subsequent select osteoblast adhesion was enhanced on nanophase ceramics; these material formulations also promoted calcium and, subsequent, calcium-mediated vitronectin adsorption. By demonstrating that bioceramics can be designed and fabricated (through control of grain and pore size) to possess improved cytocompatibility properties for select osteoblast function, the results of the present study have made fundamental and groundbreaking contributions to the emerging fields of cellular/tissue engineering and nanophase material science. Undoubtedly, as this study demonstrated for the first time, nanophase ceramics have great potential to become the next generation, choice orthopaedic/dental biomaterial to enhance bonding to juxtaposed bone and, thus, increase implant efficacy.

Webster, Thomas Jay

130

Chemical oxidation kinetics of pyrite in bioleaching processes  

Microsoft Academic Search

Bio-oxidation experiments with Leptospirillum bacteria were used to determine the chemical oxidation kinetics of pyrite in acidic ferric sulphate solutions (0.1–0.2 M) at 30°C and pH 1.6. The proposed method is applicable because the oxidation of pyrite with Leptospirillum bacteria consists of two sub-processes: (i) Pyrite is chemically oxidized with ferric iron to sulphate and ferrous iron, (ii) Ferric iron

M Boon; J. J Heijnen

1998-01-01

131

Limit of miscibility and nanophase separation in associated mixtures.  

PubMed

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

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

2013-08-22

132

What do we really know about the atomic-scale structures of nanophase materials?  

Microsoft Academic Search

Robert W. Balluffi has spent a rich research lifetime critically investigating and elucidating the atomic scale defect structures of materials. Now, a new class of ultrafine-grained materials has been created in which such defects exercise a dominant role. The structures of these new nanophase materials, both metals and ceramics, have been investigated over the past several years by a wide

R. Siegel

1994-01-01

133

Proximal ligand electron donation and reactivity of the cytochrome P450 ferric-peroxo anion.  

PubMed

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 pK(a) of the ferric-peroxo anion, which favors its protonation and, therefore, Compound I formation. PMID:22444582

Sivaramakrishnan, Santhosh; Ouellet, Hugues; Matsumura, Hirotoshi; Guan, Shenheng; Moėnne-Loccoz, Pierre; Burlingame, Alma L; Ortiz de Montellano, Paul R

2012-04-18

134

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

PubMed Central

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

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

2012-01-01

135

Intravenous ferric carboxymaltose for anaemia in pregnancy  

PubMed Central

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 15 mg/kg between 24 and 40 weeks of pregnancy (median 35 weeks 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

2014-01-01

136

Shewanella spp. Use Acetate as an Electron Donor for Denitrification but Not Ferric Iron or Fumarate Reduction  

PubMed Central

Lactate but not acetate oxidation was reported to support electron acceptor reduction by Shewanella spp. under anoxic conditions. We demonstrate that the denitrifiers Shewanella loihica strain PV-4 and Shewanella denitrificans OS217 utilize acetate as an electron donor for denitrification but not for fumarate or ferric iron reduction. PMID:23396327

Yoon, Sukhwan; Sanford, Robert A.

2013-01-01

137

Fulvic Acid Oxidation State Detection Using Fluorescence  

E-print Network

Fulvic Acid Oxidation State Detection Using Fluorescence Spectroscopy L I S A K L A P P E R , Ā§ D I can act as electron shuttles in the microbial reduction of ferric iron. Field studies of electron electrons from Geobacter metallireducens to ferric iron in the microbial oxidation of acetate (Figure 1) (25

Lovley, Derek

138

Ferric carboxymaltose: a review of its use in iron deficiency.  

PubMed

Ferric carboxymaltose (Ferinject(®), Injectafer(®)) is an intravenous iron preparation approved in numerous countries for the treatment of iron deficiency. A single high dose of ferric carboxymaltose (up to 750 mg of iron in the US and 1,000 mg of iron in the EU) can be infused in a short time frame (15 min). Consequently, fewer doses of ferric carboxymaltose may be needed to replenish iron stores compared with some other intravenous iron preparations (e.g. iron sucrose). Ferric carboxymaltose improved self-reported patient global assessment, New York Heart Association functional class and exercise capacity in patients with chronic heart failure and iron deficiency in two randomized, placebo-controlled trials (FAIR-HF and CONFIRM-HF). In other randomized controlled trials, ferric carboxymaltose replenished iron stores and corrected anaemia in various populations with iron-deficiency anaemia, including patients with chronic kidney disease, inflammatory bowel disease or heavy uterine bleeding, postpartum iron-deficiency anaemia and perioperative anaemia. Intravenous ferric carboxymaltose was generally well tolerated, with a low risk of hypersensitivity reactions. It was generally better tolerated than oral ferrous sulfate, mainly reflecting a lower incidence of gastrointestinal adverse effects. The most common laboratory abnormality seen in ferric carboxymaltose recipients was transient, asymptomatic hypophosphataemia. The higher acquisition cost of ferric carboxymaltose appeared to be offset by lower costs for other items, with the potential for cost savings. In conclusion, ferric carboxymaltose is an important option for the treatment of iron deficiency. PMID:25428711

Keating, Gillian M

2015-01-01

139

The reactions of a dinuclear ferric complex (oxo) di-iron(III) triethylenetetraamminehexaacetate, Fe 2O(ttha) 2?, with oxidizing and reducing free radicals. A pulse radiolysis study  

Microsoft Academic Search

The rate constants at which oxidizing and reducing radicals react with the dinuclear iron(III) complex Fe2O(ttha)2? were measured in neutral aqueous solution. The rate constants for reduction of the complex by ·CO2.? CH3.CHOH and O2.? were found to be comparable with rate constants previously measured in mononuclear iron(III) polyaminocarboxylate systems. Fe2O(ttha)2? reacts slowly with O2.? (k8 = (1.2 ± 0.2)

James D. Rush; Diane E. Cabelli

1997-01-01

140

Mechanical and Optical Characterizations of Nanophase Diamond Films Prepared by a Laser Plasma Discharge Source.  

NASA Astrophysics Data System (ADS)

Films of nanophase diamond can be deposited at room temperature with a laser plasma discharge source of multiply charged carbon ions without the use of any catalyst in the growth mechanism. The beam from a Q-switched Nd:YAG laser is focused on graphite at intensities in excess of 10^{11} Wcm^ {-2} and the resulting plasma ejects carbon ions carrying energies of about 1 keV through a discharge space to the substrate to be coated. The nanophase diamond films that condense are composed of nanometer scale nodules of sp^3 bonded carbon. The high energy of condensation from the laser plasma source provides both the chemical bonding of such films to a wide variety of substrates and for low values of residual compressive stress. In this work, mechanical and optical characterizations of nanophase diamond films were extensively studied. An advanced nanoindentation technique utilizing the NanoTest device was used to measure the hardness of the films prepared by the UT-Dallas laser deposition system and other techniques. The raw data produced was analyzed with a conventional procedure and a hardness value of 125 GPa was obtained. To avoid model dependent interpretation, a differential loading pressure, independent of plastic depth, was used to give a lower limit on the hardness directly for the raw data. Comparable values of this lower limit, near 75 GPa was measured on crystalline diamond prepared by CVD and on nanophase diamond deposited by the laser plasma method. It was shown that the hardness of nanophase diamond films increased with laser intensities used to produce them. The nanoindentation technique was also used to assess the bonding strength of the films. Reproducible discontinuities in the variation of the penetration depth with load were obtained when adhesion failure occurred under indentations. Adhesion strength of films prepared from core and periphery of laser plasma were compared by means of nanoindentation and Rutherford backscattering techniques and impressive adhesion strength was found for films deposited from carbon ions passing through the core part of laser plasma. The optical properties at infrared (IR) wavelengths were studied with the aid of a Fourier transform infrared (FTIR) spectrometer. Transmission spectra of several free standing films on silicon frames were obtained. Using a simple model considering rough surface scattering and free carrier absorption, satisfactory fits to these transmission spectra were obtained and from them the optical properties of refractive index were extracted. The characterization studies performed in this research indicated a great potential for nanophase diamond films in optical and mechanical applications.

You, Jonghun

141

The reactions of a dinuclear ferric complex (oxo) di-iron(III) triethylenetetraamminehexaacetate, Fe2O(ttha)2-, with oxidizing and reducing free radicals. A pulse radiolysis study  

Microsoft Academic Search

The rate constants at which oxidizing and reducing radicals react with the dinuclear iron(III) complex Fe2O(ttha)2- were measured in neutral aqueous solution. The rate constants for reduction of the complex by .CO˙-2 CH˙3CHOH and O˙-2 were found to be comparable with rate constants previously measured in mononuclear iron(III) polyaminocarboxylate systems. Fe2O(ttha)2- reacts slowly with O˙-2 (k8 = (1.2 +\\/- 0.2)

James D. Rush; Diane E. Cabelli

1997-01-01

142

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

PubMed

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

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

2005-01-01

143

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

NASA Technical Reports Server (NTRS)

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.

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

2006-01-01

144

Phyllosilicates and nanophase aluminosilicates at Mawrth Vallis and their geochemical implications  

NASA Astrophysics Data System (ADS)

Modelling of TES data has shown the presence of allophane in several sites on Mars with the highest abundances in the Mawrth Vallis region [1]. Analyses of CRISM data at Mawrth Vallis are also consistent with the nanophase aluminosilicates allophane and imogolite in the upper Al/Si-rich phyllosilicatebearing unit [2,3]. We report here on recent lab analyses of several allophane and imogolite samples and new analyses of CRISM and TES data enabled with this larger spectral library. Clay-type components are modelled across the Mawrth Vallis region at ~50-75 vol% in bright units and ~35-55 vol% in dark units using TES data. Identification of nanophase aluminosilicates at Mawrth Vallis helps reconcile the NIR and TIR data of the region, and has important implications for understanding past pedogenic and igneous processes.

Bishop, J. L.; Rampe, E.

2013-09-01

145

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

PubMed Central

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. PMID:22873570

2012-01-01

146

What do we really know about the atomic scale structures of nanophase materials?  

SciTech Connect

Robert W. Balluffi has spent a rich research lifetime critically investigating and elucidating the atomic scale defect structures of materials. Now, a new class of ultrafine-grained materials has been created in which such defects exercise a dominant role. The structures of these new nanophase materials, both metals and ceramics, have been investigated over the past several years by a wide range of experimental methods. These studies have included observations by x-ray and neutron scattering, transmission and scanning electron microscopy, Moessbauer, Raman, and positron annihilation spectroscopy, and most recently scanning tunneling and atomic force microscopy and nuclear magnetic resonance. While the experiments have yielded considerable useful information about the structures of nanophase materials on a variety of length scales, much about the local atomic arrangements in the grains and interfaces of these materials remains to be elucidated. The present status of the author`s knowledge of these structures is reviewed and some future research needs and opportunities are considered.

Siegel, R.W. [Argonne National Lab., IL (United States). Materials Science Div.

1994-06-01

147

Hydroxyl radical formation from the auto-reduction of a ferric citrate complex.  

PubMed

When a ferric citrate complex is prepared from citric acid and ferric chloride, and the pH value left unchanged, a reduction of the iron moiety takes place. Within several hours a substantial yield of ferrous ions can be detected in the solution. When placed in a phosphate buffer pH 7.0 with a suitable detector molecule, oxidative damage to the detector molecule can be observed. Thus, deoxyribose is degraded with the release of thiobarbituric acid-reactive material and benzoate is hydroxylated to form fluorescent dihydroxy products. Damage can be prevented by scavengers of the hydroxyl radical such as mannitol, formate the thiourea, by catalase and by the protein caeruloplasmin, suggesting that Fenton chemistry occurs leading to the formation of hydroxyl radicals. PMID:1665838

Gutteridge, J M

1991-01-01

148

Matter Mineralization with the Reduction of Ferric Iron  

E-print Network

aspectsof microbial reduction of ferric iron. Introduction Microbial respiration with ferric iron, Fe the anaerobic decomposition of organic matter in sediments and soils. In contrast to the detailed envi iron reduction in the decomposition of organic matter in anaerobic environments. #12;Microbia

Lovley, Derek

149

Energy transduction by anaerobic ferric iron respiration in Thiobacillus ferrooxidans  

SciTech Connect

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.

Pronk, J.T.; Liem, K.; Bos, P.; Kuenen, J.G. (Delft Univ. of Technology (Netherlands))

1991-07-01

150

The leaching of nickeliferous laterite with ferric chloride  

NASA Astrophysics Data System (ADS)

Several experiments were conducted to investigate the extraction of nickel from nickeliferous laterite by ferric chloride solutions as a function of pulp density, solution composition, and temperature. Solubility relationships for goethite and nickel laterite in aqueous solution were reviewed in terms of leaching rates and reaction mechanisms. Generally, the amount of nickel extracted increased with temperature, the amount of “free acid,” and ferric chloride concentration; however, the amount was inhibited by ferrous chloride. In this investigation, as much as 96 pct of the available nickel was extracted by ferric chloride solution. Nickel extraction was found to be more dependent on ferric chloride concentration than on the concentration of hydrochloric acid. Mechanistically, nickel extraction occurred by the formation of an intermediate ferric chloride complex, which was then hydrolyzed to hematite.

Munroe, Norman D. H.

1997-12-01

151

Immobilization of arsenite and ferric iron by Acidithiobacillus ferrooxidans and its relevance to acid mine drainage.  

PubMed

Weathering of the As-rich pyrite-rich tailings of the abandoned mining site of Carnoulčs (southeastern France) results in the formation of acid waters heavily loaded with arsenic. Dissolved arsenic present in the seepage waters precipitates within a few meters from the bottom of the tailing dam in the presence of microorganisms. An Acidithiobacillus ferrooxidans strain, referred to as CC1, was isolated from the effluents. This strain was able to remove arsenic from a defined synthetic medium only when grown on ferrous iron. This A. ferrooxidans strain did not oxidize arsenite to arsenate directly or indirectly. Strain CC1 precipitated arsenic unexpectedly as arsenite but not arsenate, with ferric iron produced by its energy metabolism. Furthermore, arsenite was almost not found adsorbed on jarosite but associated with a poorly ordered schwertmannite. Arsenate is known to efficiently precipitate with ferric iron and sulfate in the form of more or less ordered schwertmannite, depending on the sulfur-to-arsenic ratio. Our data demonstrate that the coprecipitation of arsenite with schwertmannite also appears as a potential mechanism of arsenite removal in heavily contaminated acid waters. The removal of arsenite by coprecipitation with ferric iron appears to be a common property of the A. ferrooxidans species, as such a feature was observed with one private and three collection strains, one of which was the type strain. PMID:14532077

Duquesne, K; Lebrun, S; Casiot, C; Bruneel, O; Personné, J-C; Leblanc, M; Elbaz-Poulichet, F; Morin, G; Bonnefoy, V

2003-10-01

152

Immobilization of Arsenite and Ferric Iron by Acidithiobacillus ferrooxidans and Its Relevance to Acid Mine Drainage  

PubMed Central

Weathering of the As-rich pyrite-rich tailings of the abandoned mining site of Carnoulčs (southeastern France) results in the formation of acid waters heavily loaded with arsenic. Dissolved arsenic present in the seepage waters precipitates within a few meters from the bottom of the tailing dam in the presence of microorganisms. An Acidithiobacillus ferrooxidans strain, referred to as CC1, was isolated from the effluents. This strain was able to remove arsenic from a defined synthetic medium only when grown on ferrous iron. This A. ferrooxidans strain did not oxidize arsenite to arsenate directly or indirectly. Strain CC1 precipitated arsenic unexpectedly as arsenite but not arsenate, with ferric iron produced by its energy metabolism. Furthermore, arsenite was almost not found adsorbed on jarosite but associated with a poorly ordered schwertmannite. Arsenate is known to efficiently precipitate with ferric iron and sulfate in the form of more or less ordered schwertmannite, depending on the sulfur-to-arsenic ratio. Our data demonstrate that the coprecipitation of arsenite with schwertmannite also appears as a potential mechanism of arsenite removal in heavily contaminated acid waters. The removal of arsenite by coprecipitation with ferric iron appears to be a common property of the A. ferrooxidans species, as such a feature was observed with one private and three collection strains, one of which was the type strain. PMID:14532077

Duquesne, K.; Lebrun, S.; Casiot, C.; Bruneel, O.; Personné, J.-C.; Leblanc, M.; Elbaz-Poulichet, F.; Morin, G.; Bonnefoy, V.

2003-01-01

153

Potential Role for Extracellular Glutathione-Dependent Ferric Reductase in Utilization of Environmental and Host Ferric Compounds by Histoplasma capsulatum  

PubMed Central

The mammalian host specifically limits iron during Histoplasma capsulatum infection, and fungal acquisition of iron is essential for productive infection. H. capsulatum expresses several iron acquisition mechanisms under iron-limited conditions in vitro. These components include hydroxamate siderophores, extracellular glutathione-dependent ferric reductase enzyme, extracellular nonproteinaceous ferric reductant(s), and cell surface ferric reducing agent(s). We examined the relationship between these mechanisms and a potential role for the extracellular ferric reductase in utilization of environmental and host ferric compounds through the production of free, soluble Fe(II). Siderophores and ferric reducing agents were coproduced under conditions of iron limitation. The H. capsulatum siderophore dimerum acid and the structurally similar basidiomycete siderophore rhodotorulic acid acted as substrates for the ferric reductase, and rhodotorulic acid removed Fe(III) bound by transferrin. The mammalian Fe(III)-binding compounds hemin and transferrin served both as substrates for the ferric reductase and as iron sources for yeast-phase growth at neutral pH. In the case of transferrin, there was a correlation between the level of iron saturation and efficacy for both of these functions. Our data are not consistent with an entirely pH-dependent mechanism of iron acquisition from transferrin, as has been suggested to occur in the macrophage phagolysosome. The foreign siderophore ferrioxamine B also acted as a substrate for the ferric reductase, while the foreign siderophore ferrichrome did not. Both ferrioxamine and ferrichrome served as iron sources for yeast- and mold-phase growth, the latter presumably by some other acquisition mechanism(s). PMID:11705947

Timmerman, Michelle M.; Woods, Jon P.

2001-01-01

154

21 CFR 73.2298 - Ferric ammonium ferrocyanide.  

Code of Federal Regulations, 2011 CFR

...GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION...specifications. The color additive ferric ammonium ferrocyanide...amounts consistent with good manufacturing practice. (c) Labeling. The color additive and any mixture...

2011-04-01

155

21 CFR 73.2298 - Ferric ammonium ferrocyanide.  

Code of Federal Regulations, 2010 CFR

...GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION...specifications. The color additive ferric ammonium ferrocyanide...amounts consistent with good manufacturing practice. (c) Labeling. The color additive and any mixture...

2010-04-01

156

21 CFR 73.1025 - Ferric ammonium citrate.  

Code of Federal Regulations, 2010 CFR

...Ferric ammonium citrate may be safely used in combination with pyrogallol (as listed in § 73.1375), for coloring plain and chromic catgut sutures for use in general and ophthalmic surgery subject to the following conditions: (1) The dyed suture...

2010-04-01

157

21 CFR 73.2298 - Ferric ammonium ferrocyanide.  

Code of Federal Regulations, 2013 CFR

...GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION...specifications. The color additive ferric ammonium ferrocyanide...amounts consistent with good manufacturing practice. (c) Labeling. The color additive and any mixture...

2013-04-01

158

21 CFR 73.2298 - Ferric ammonium ferrocyanide.  

Code of Federal Regulations, 2012 CFR

...GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION...specifications. The color additive ferric ammonium ferrocyanide...amounts consistent with good manufacturing practice. (c) Labeling. The color additive and any mixture...

2012-04-01

159

21 CFR 73.2298 - Ferric ammonium ferrocyanide.  

...GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION...specifications. The color additive ferric ammonium ferrocyanide...amounts consistent with good manufacturing practice. (c) Labeling. The color additive and any mixture...

2014-04-01

160

The leaching of tetrahedrite in ferric chloride solutions  

Microsoft Academic Search

This paper presents a study of the kinetics of the leaching of tetrahedrite in FeCl3–NaCl–HCl solutions for temperatures between 60°C and 104°C and ferric ion concentrations of 0.001 to 1 M at atmospheric pressure. The shrinking core model was applied to the results. The calculated activation energy is 65±6 kJ\\/mol; the order of the reaction with respect to ferric ion

M. Joana Neiva Correia; Jorge R Carvalho; A. John Monhemius

2000-01-01

161

Fe-heme conformations in ferric myoglobin.  

PubMed Central

X-ray absorption near-edge structure (XANES) spectra of ferric myoglobin from horse heart have been acquired as a function of pH (between 5.3 and 11.3). At pH = 11.3 temperature-dependent spectra (between 20 and 293 K) have been collected as well. Experimental data solve three main conformations of the Fe-heme: the first, at low pH, is related to high-spin aquomet-myoglobin (Mb+OH2). The other two, at pH 11.3, are related to hydroxymet-myoglobin (Mb+OH-), and are in thermal equilibrium, corresponding to high- and low-spin Mb+OH-. The structure of the three Fe-heme conformations has been assigned according to spin-resolved multiple scattering simulations and fitting of the XANES data. The chemical transition between Mb+OH2 and high-spin Mb+OH-, and the spin transition of Mb+OH-, are accompanied by changes of the Fe coordination sphere due to its movement toward the heme plane, coupled to an increase of the axial asymmetry. PMID:9826636

Longa, S D; Pin, S; Cortčs, R; Soldatov, A V; Alpert, B

1998-01-01

162

Ferrous-Ferric Ion exchange dosemeter.  

PubMed

In this work a three-dimensional ferrous-ferric ion exchange dosemeter is proposed and the dose response measured. The dosemeter consists of strong acid cation exchange resin beads in the H form in water. Amberlyst 15 Wet beads with a harmonic mean diameter of 0.600-0.850 mm were prepared by soaking them in an aqueous solution of ferrous ammonium sulphate to exchange ferrous ions for H(+) ions. The beads were rinsed with distilled water and packed in glass vials. Sets of samples with ferrous ion concentrations of 0.5 and 1.0 mM were dosed with 6 MV X rays from a Varian 2100C linac. The spin-lattice relaxation time constants (T1) for the samples were measured using an Apollo spectrometer (Tecmag, Houston, TX) interfaced to a 1.5 T magnet (Magnex, Abingdon, UK). Each sample had two T1 values; a long T1 at 1200 ms that did not significantly change with dose and a short T1 that ranged from 56 ms at 0 Gy to 36 ms at 100 Gy. The R1 vs. dose responses were linear with slopes of 0.066 and 0.079 s(-1) Gy(-1). PMID:16644977

Bauhs, John A; Hammer, Bruce E

2006-01-01

163

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

NASA Technical Reports Server (NTRS)

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.

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

1973-01-01

164

Magnetic phases in lunar fines: metallic Fe or ferric oxides?  

Microsoft Academic Search

The ferromagnetic resonance ( g = 2.08 ± 0.03) 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 indicates that

Fun-Dow Tsay; Sunney I. Chan; Stanley L. Manatt

1973-01-01

165

Interactions of ferric ions with olive oil phenolic compounds.  

PubMed

The ferric complexing capacity of four phenolic compounds, occurring in olives and virgin olive oil, namely, oleuropein, hydroxytyrosol, 3,4-dihydroxyphenylethanol-elenolic acid (3,4-DHPEA-EA), and 3,4-dihydroxyphenylethanol-elenolic acid dialdehyde (3,4-DHPEA-EDA), and their stability in the presence of ferric ions were studied. At pH 3.5, all compounds formed a reversible 1:1 complex with ferric ions, but hydroxytyrosol could also form complexes containing >1 ferric ion per phenol molecule. At pH 5.5, the complexes between ferric ions and 3,4-DHPEA-EA or 3,4-DHPEA-EDA were relatively stable, indicating that the antioxidant activity of 3,4-DHPEA-EA or 3,4-DHPEA-EDA at pH 5.5 is partly due to their metal-chelating activity. At pH 7.4, a complex containing >1 ferric ion per phenol molecule was formed with hydroxytyrosol. Oleuropein, 3,4-DHPEA-EA, and 3,4-DHPEA-EDA also formed insoluble complexes at this pH. There was no evidence for chelation of Fe(II) by hydroxytyrosol or its derivatives. At all pH values tested, hydroxytyrosol was the most stable compound in the absence of Fe(III) but the most sensitive to the presence of Fe(III). PMID:15796614

Paiva-Martins, Fįtima; Gordon, Michael H

2005-04-01

166

NADH-ferric reductase activity associated with dihydropteridine reductase.  

PubMed

In mammals dietary ferric iron is reduced to ferrous iron for more efficient absorption by the intestine. Analysis of a pig duodenal membrane fraction revealed two NADH-dependent ferric reductase activities, one associated with a b-type cytochrome and the other not. Purification and characterization of the non-cytochrome ferric reductase identified a 31 kDa protein. MALDI-MS analysis and amino acid sequencing identified the ferric reductase as being related to the 26 kDa liver NADH-dependent quinoid dihydropteridine reductase (DHPR). The NADH-dependent DHPR ferric reductase activity was found to be pteridine-independent since exhaustive dialysis did not reduce activity and heat-inactivation destroyed activity. In intestinal Caco-2 cells, DHPR mRNA levels were found to be regulated by iron. Thus, DHPR appears to be a dual function enzyme, a NADH-dependent dihydopteridine reductase and an iron-regulated, NADH-dependent, pteridine-independent ferric reductase. PMID:10814540

Lee, P L; Halloran, C; Cross, A R; Beutler, E

2000-05-19

167

Effect of Fe-chelating complexes on a novel M2FC performance with ferric chloride and ferricyanide catholytes.  

PubMed

As an effort to better utilize the microbial fuel cell (MFC) technology, we previously proposed an innovative MFC system named M2FC consisting of ferric-based MFC part and ferrous-based fuel cell (FC) part. In this reactor, ferric ion, the catholyte in the MFC part, was efficiently regenerated by the FC part with the generation of additional electricity. When both units were operated separately, the ferric-based MFC part produced approximately 1360 mW m(-2) of power density with FeCl(3) as catholyte and Fe-citrate as anolyte. The ferrous-based FC part with FeCl(3) as catholyte and Fe-EDTA as anolyte displayed the highest power density (1500 mW m(-2)), while that with ferricyanide as catholyte and Fe-noligand as anolyte had the lowest power density (380 mW m(-2)). The types of catholytes and chelating complexes as anolyte were found to play important roles in the reduction of ferric ions and oxidation of ferrous ion. Linear sweep voltammetry results supported that the cathode electrolytes were electrically active and these agreed well with the M2FC reactor performance. These results clearly showed that ligands played critical role in the efficiency and rate for recycling iron ion and thus the M2FC performance. PMID:22018860

Chung, Kyungmi; Lee, Ilgyu; Han, Jong-In

2012-01-01

168

Flue gas desulfurization by FeSO 4 solutions and coagulation performance of the polymeric ferric sulfate by-product  

Microsoft Academic Search

A process for flue gas desulfurization (FGD) with simultaneous polymeric ferric sulfate (PFS) production was investigated, using a ferrous sulfate (FeSO4) solution as the absorbent, sulfur dioxide (SO2) in flue gas as the raw material and sodium chlorate (NaClO3) as the oxidant. The results indicate that SO2 removal efficiency in a packed column could be maintained at a high level,

Yu Zhang; Shiyuan Guo; Jiti Zhou; Chengyu Li; Guodong Wang

2010-01-01

169

Evidence of the direct involvement of the substrate TCP radical in functional switching from oxyferrous O2 carrier to ferric peroxidase in the dual-function hemoglobin/dehaloperoxidase from Amphitrite ornata.  

PubMed

The coelomic O2-binding hemoglobin dehaloperoxidase (DHP) from the sea worm Amphitrite ornata is a dual-function heme protein that also possesses a peroxidase activity. Two different starting oxidation states are required for reversible O2 binding (ferrous) and peroxidase (ferric) activity, bringing into question how DHP manages the two functions. In our previous study, the copresence of substrate 2,4,6-trichlorophenol (TCP) and H2O2 was found to be essential for the conversion of oxy-DHP to enzymatically active ferric DHP. On the basis of that study, a functional switching mechanism involving substrate radicals (TCP(•)) was proposed. To further support this mechanism, herein we report details of our investigations into the H2O2-mediated conversion of oxy-DHP to the ferric or ferryl ([TCP] < [H2O2]) state triggered by both biologically relevant [TCP and 4-bromophenol (4-BP)] and nonrelevant (ferrocyanide) compounds. At <50 ?M H2O2, all of these conversion reactions are completely inhibited by ferric heme ligands (KCN and imidazole), indicating the involvement of ferric DHP. Furthermore, the spin-trapping reagent 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) effectively inhibits the TCP/4-BP (but not ferrocyanide)-triggered conversion of oxy-DHP to ferric DHP. These results and O2 concentration-dependent conversion rates observed in this study demonstrate that substrate TCP triggers the conversion of oxy-DHP to a peroxidase by TCP(•) oxidation of the deoxyferrous state. TCP(•) is progressively generated, by increasingly produced amounts of ferric DHP, upon H2O2 oxidation of TCP catalyzed initially by trace amounts of ferric enzyme present in the oxy-DHP sample. The data presented herein further address the mechanism of how the halophenolic substrate triggers the conversion of hemoglobin DHP into a peroxidase. PMID:24972312

Sun, Shengfang; Sono, Masanori; Du, Jing; Dawson, John H

2014-08-01

170

Kinetics of iron acquisition from ferric siderophores by Paracoccus denitrificans.  

PubMed Central

The kinetics of iron accumulation by iron-starved Paracoccus denitrificans during the first 2 min of exposure to 55Fe-labeled ferric siderophore chelates is described. Iron is acquired from the ferric chelate of the natural siderophore L-parabactin in a process exhibiting biphastic kinetics by Lineweaver-Burk analysis. The kinetic data for 1 microM less than [Fe L-parabactin] less than 10 microM fit a regression line which suggests a low-affinity system (Km = 3.9 +/- 1.2 microM, Vmax = 494 pg-atoms of 55Fe min-1 mg of protein-1), whereas the data for 0.1 microM less than or equal to [Fe L-parabactin] less than or equal to 1 microM fit another line consistent with a high-affinity system (Km = 0.24 +/- 0.06 microM, Vmax = 108 pg-atoms of 55Fe min-1 mg of protein-1). The Km of the high-affinity uptake is comparable to the binding affinity we had previously reported for the purified ferric L-parabactin receptor protein in the outer membrane. In marked contrast, ferric D-parabactin data fit a single regression line corresponding to a simple Michaelis-Menten process with comparatively low affinity (Km = 3.1 +/- 0.9 microM, Vmax = 125 pg-atoms of 55Fe min-1 mg of protein-1). Other catecholamide siderophores with an intact oxazoline ring derived from L-threonine (L-homoparabactin, L-agrobactin, and L-vibriobactin) also exhibit biphasic kinetics with a high-affinity component similar to ferric L-parabactin. Circular dichroism confirmed that these ferric chelates, like ferric L-parabactin, exist as the lambda enantiomers. The A forms ferric parabactin (ferrin D- and L-parabactin A), in which the oxazoline ring is hydrolyzed to the open-chain threonyl structure, exhibit linear kinetics with a comparatively high Km (1.4 +/- 0.3 microM) and high Vmax (324 pg-atoms of 55Fe min-1 of protein-1). Furthermore, the marked stereospecificity seen between ferric D- and L-parabactins is absent; i.e., iron acquisition from ferric parabactin A is non stereospecific. The mechanistic implications of these findings in relation to a stereospecific high-affinity binding followed by a nonstereospecific postreceptor processing is discussed. PMID:2185228

Bergeron, R J; Weimar, W R

1990-01-01

171

Kinetics of iron acquisition from ferric siderophores by Paracoccus denitrificans.  

PubMed

The kinetics of iron accumulation by iron-starved Paracoccus denitrificans during the first 2 min of exposure to 55Fe-labeled ferric siderophore chelates is described. Iron is acquired from the ferric chelate of the natural siderophore L-parabactin in a process exhibiting biphastic kinetics by Lineweaver-Burk analysis. The kinetic data for 1 microM less than [Fe L-parabactin] less than 10 microM fit a regression line which suggests a low-affinity system (Km = 3.9 +/- 1.2 microM, Vmax = 494 pg-atoms of 55Fe min-1 mg of protein-1), whereas the data for 0.1 microM less than or equal to [Fe L-parabactin] less than or equal to 1 microM fit another line consistent with a high-affinity system (Km = 0.24 +/- 0.06 microM, Vmax = 108 pg-atoms of 55Fe min-1 mg of protein-1). The Km of the high-affinity uptake is comparable to the binding affinity we had previously reported for the purified ferric L-parabactin receptor protein in the outer membrane. In marked contrast, ferric D-parabactin data fit a single regression line corresponding to a simple Michaelis-Menten process with comparatively low affinity (Km = 3.1 +/- 0.9 microM, Vmax = 125 pg-atoms of 55Fe min-1 mg of protein-1). Other catecholamide siderophores with an intact oxazoline ring derived from L-threonine (L-homoparabactin, L-agrobactin, and L-vibriobactin) also exhibit biphasic kinetics with a high-affinity component similar to ferric L-parabactin. Circular dichroism confirmed that these ferric chelates, like ferric L-parabactin, exist as the lambda enantiomers. The A forms ferric parabactin (ferrin D- and L-parabactin A), in which the oxazoline ring is hydrolyzed to the open-chain threonyl structure, exhibit linear kinetics with a comparatively high Km (1.4 +/- 0.3 microM) and high Vmax (324 pg-atoms of 55Fe min-1 of protein-1). Furthermore, the marked stereospecificity seen between ferric D- and L-parabactins is absent; i.e., iron acquisition from ferric parabactin A is non stereospecific. The mechanistic implications of these findings in relation to a stereospecific high-affinity binding followed by a nonstereospecific postreceptor processing is discussed. PMID:2185228

Bergeron, R J; Weimar, W R

1990-05-01

172

Formation of Metallic Nanophases in Polymeric Matrices for Space Applications  

NASA Technical Reports Server (NTRS)

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.

Orwoll, Robert A.; Thompson, David W.

1999-01-01

173

Hydrogen and Ferric Iron in Mars Materials  

NASA Technical Reports Server (NTRS)

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.

Dyar, Melinda D.

2004-01-01

174

Ferric microperoxidase-11 catalyzes peroxynitrite isomerization.  

PubMed

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 20.0°C. The value of the second-order rate constant (kon) for peroxynitrite isomerization to NO3(-) by MP11-Fe(III) decreases from (1.1±0.1)×10(5)M(-1)s(-1), at pH3.6, to (6.1±0.6)×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

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

2015-03-01

175

Nanoporous thin films from nanophase-separated hybrids of block copolymer/metal salt  

NASA Astrophysics Data System (ADS)

Block copolymers self-assemble into periodic nanostructures, i.e. nanophase-separated structures, which can be scaffolds for nano-applications such as nanoporous membranes, nanolithographic masks, photonic crystals, etc. In this study, we report facile preparation to achieve nanoporous thin films from nanophase-separated hybrids comprising polystyrene-b-poly(4-vinylpyridine) (PS-P4VP, Mn=54k, PDI=1.13, fs=0.61) and water-soluble iron(III) chloride (FeCl3), where FeCl3 are incorporated into a P4VP phase via metal-to-ligand coordination. To obtain a nanoporous film, firstly a hybrid thin film was prepared by microtoming. Then, the film was immersed into water to remove metal salts, this simple procedure can produce nanoporous thin film. Morphological observations were conducted by using transmission electron microscopy (TEM). Ordered cylindrical nanopores were observed in the thin film of the water-immersed hybrid, which originally presents cylindrical nanodomains. The nanoporous film was modified by loading another metal salt, samarium(III) nitrate, into nanopores via coordination between the metal salt and P4VP tethered to the pore walls. The structure of the sample after modification was evaluated by TEM and an energy dispersive X-ray spectroscopy.

Sageshima, Yoshio; Noro, Atsushi; Matsushita, Yushu

2013-03-01

176

AN IMPROVED SPECTROSCOPIC MODEL FOR SPACE WEATHERING THROUGH THE FORMATION OF A VAPOR DEPOSITION LAYER CONTAINING NANOPHASE REDUCED IRON  

E-print Network

LAYER CONTAINING NANOPHASE REDUCED IRON PARTICLES. T. Nimura1, 2, 3 , T. Hiroi1 , and C. M. Pieters1 , 1: Visible and near-infrared reflec- tance spectroscopy has been a useful method for re- motely detecting, and attenuated absorption features (e.g., [1]). Thus, important features for detecting component min- erals

Hiroi, Takahiro

177

Nanophase Segregation and Water Dynamics in the Dendrion Diblock Copolymer Formed from the Frechet Polyaryl Ethereal Dendrimer and Linear PTFE  

E-print Network

Nanophase Segregation and Water Dynamics in the Dendrion Diblock Copolymer Formed from the FreĀ“chet determine the structure and dynamics of the dendrion formed by second-generation FreĀ“chet polyaryl ethereal found28 that Nafion polymers with identical chemical composi- tions but different distributions

Goddard III, William A.

178

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

SciTech Connect

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.

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

1980-12-01

179

Mechanism of Bacterial Pyrite Oxidation  

PubMed Central

The oxidation by Ferrobacillus ferrooxidans of untreated pyrite (FeS2) as well as HCl-pretreated pyrite (from which most of the acid-soluble iron species were removed) was studied manometrically. Oxygen uptake was linear during bacterial oxidation of untreated pyrite, whereas with HCl-pretreated pyrite both a decrease in oxygen uptake at 2 hr and nonlinear oxygen consumption were observed. Ferric sulfate added to HCl-pretreated pyrite restored approximately two-thirds of the decrease in total bacterial oxygen uptake and caused oxygen uptake to revert to nearly linear kinetics. Ferric sulfate also oxidized pyrite in the absence of bacteria and O2; recovery of ferric and ferrous ions was in excellent agreement with the reaction Fe2(SO4)3 + FeS2 = 3FeSO4 + 2S, but the elemental sulfur produced was negligible. Neither H2S nor S2O32? was a product of the reaction. It is probable that two mechanisms of bacterial pyrite oxidation operate concurrently: the direct contact mechanism which requires physical contact between bacteria and pyrite particles for biological pyrite oxidation, and the indirect contact mechanism according to which the bacteria oxidize ferrous ions to the ferric state, thereby regenerating the ferric ions required for chemical oxidation of pyrite. PMID:6051342

Silverman, Melvin P.

1967-01-01

180

Intravenous ferric carboxymaltose accelerates erythropoietic recovery from experimental malarial anemia.  

PubMed

Iron restriction has been proposed as a cause of erythropoietic suppression in malarial anemia; however, the role of iron in malaria remains controversial, because it may increase parasitemia. To investigate the role of iron-restricted erythropoiesis, A/J mice were infected with Plasmodium chabaudi AS, treated with intravenous ferric carboxymaltose at different times, and compared with untreated controls. Iron treatment significantly increased weight and hemoglobin nadirs and provided enhanced reticulocytosis and faster recovery, compared with controls. Our findings challenge the restrictive use of iron therapy in malaria and show the need for trials of intravenous ferric carboxymaltose as an adjunctive treatment for severe malarial anemia. PMID:22357662

Maretty, Lasse; Sharp, Rebecca Emilie; Andersson, Mikael; Kurtzhals, Jųrgen A L

2012-04-01

181

Construction techniques for adiabatic demagnetization refrigerators using ferric ammonium alum  

NASA Astrophysics Data System (ADS)

We describe techniques used to fabricate the cold stage of an adiabatic demagnetization refrigerator that uses the paramagnetic salt ferric ammonium alum. We discuss the design of a leak-tight housing for the salt as well as a technique for growing ferric ammonium alum crystals that results in a housing filled with >98% refrigerant. These techniques have proven to be reliable in creating robust single-stage refrigerators. Similar techniques can be used for the second stage of a dual-stage adiabatic demagnetization refrigerator.

Wilson, Grant W.; Timbie, Peter T.

1999-07-01

182

Control of Octahedral Tilts and Magnetic Properties of Perovskite Oxide Heterostructures by Substrate Symmetry  

E-print Network

Control of Octahedral Tilts and Magnetic Properties of Perovskite Oxide Heterostructures T. Pantelides3,1 1 Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA 2 The Center for Nanophase Materials Science, Oak Ridge National Laboratory

Pennycook, Steve

183

The effect of ferric-nitrilotriacetic acid on the profile of polyunsaturated fatty acids in the kidney and liver of rats  

Microsoft Academic Search

Intraperitoneal injection of the iron-complex, ferric-nitrilotriacetate (Fe-NTA), induces renal proximal tubular damage associated with oxidative damage in vivo. Fe-NTA induced a time-dependent decrease of several polyunsaturated fatty acids (PUFA), together with increased conjugated diene values and decreased cellular levels of ?-tocopherol and glutathione. At the time of maximum detectable oxidation (3 h), after the injection of a sublethal dose of

Monica Deiana; Okezie I Aruoma; Antonella Rosa; Valentina Crobu; Viviana Casu; Rosaria Piga; M. Assunta Dessi

2001-01-01

184

Soybean dihydrolipoamide dehydrogenase (ferric leghemoglobin reductase 2) interacts with and reduces ferric rice non-symbiotic hemoglobin 1§  

PubMed Central

Ferrous oxygenated hemoglobins (Hb2+O2) autoxidize to ferric Hb3+, but Hb3+ is reduced to Hb2+ by enzymatic and non-enzymatic mechanisms. We characterized the interaction between the soybean ferric leghemoglobin reductase 2 (FLbR2) and ferric rice non-symbiotic Hb1 (Hb13+). Spectroscopic analysis showed that FLbR2 reduces Hb13+. Analysis by tryptophan fluorescence quenching showed that FLbR2 interacts with Hb13+, however the use of ITC and IEF techniques revealed that this interaction is weak. In silico modeling showed that predicted FLbR2 and native Hb13+ interact at the FAD-binding domain of FLbR2 and the CD-loop and helix F of Hb13+. PMID:25431759

Gopalasubramaniam, Sabarinathan K.; Kondapalli, Kalyan C.; Millįn-Pacheco, César; Pastor, Nina; Stemmler, Timothy L.; Moran, Jose F.; Arredondo-Peter, Raśl

2014-01-01

185

Soybean dihydrolipoamide dehydrogenase (ferric leghemoglobin reductase 2) interacts with and reduces ferric rice non-symbiotic hemoglobin 1.  

PubMed

Ferrous oxygenated hemoglobins (Hb(2+)O2) autoxidize to ferric Hb(3+), but Hb(3+) is reduced to Hb(2+) by enzymatic and non-enzymatic mechanisms. We characterized the interaction between the soybean ferric leghemoglobin reductase 2 (FLbR2) and ferric rice non-symbiotic Hb1 (Hb1(3+)). Spectroscopic analysis showed that FLbR2 reduces Hb1(3+). Analysis by tryptophan fluorescence quenching showed that FLbR2 interacts with Hb1(3+), however the use of ITC and IEF techniques revealed that this interaction is weak. In silico modeling showed that predicted FLbR2 and native Hb1(3+) interact at the FAD-binding domain of FLbR2 and the CD-loop and helix F of Hb1(3+). PMID:25431759

Gopalasubramaniam, Sabarinathan K; Kondapalli, Kalyan C; Millįn-Pacheco, César; Pastor, Nina; Stemmler, Timothy L; Moran, Jose F; Arredondo-Peter, Raśl

2013-01-01

186

The facile and low temperature synthesis of nanophase hydroxyapatite crystals using wet chemistry.  

PubMed

A simple and facile wet chemistry route was used to synthesize nanophase hydroxyapatite (HaP) crystals at low temperature. The synthesis was carried out at a pH of 11.0 and at a temperature of 37°C. The resulting samples were washed several times and subjected to further analysis. XRD studies revealed that the HaP crystals were polycrystalline in nature with a crystallite size of ~15-60 ± 5 nm. SEM-EDXA images confirmed the presence of calcium (Ca), phosphorous (P), and oxygen (O) peaks. Likewise, FTIR confirmed the presence of characteristic phosphate and hydroxyl peaks in samples. Lastly, HRTEM images clearly showed distinctive lattice fringes positioned in the 100 and 002 planes. TGA analysis shows that HaP crystals can withstand higher calcination temperatures and are thermally stable. PMID:24433898

Dhand, Vivek; Rhee, K Y; Park, Soo-Jin

2014-03-01

187

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

NASA Technical Reports Server (NTRS)

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.

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

2003-01-01

188

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

NASA Technical Reports Server (NTRS)

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.

Burns, Roger G.; Fisher, Duncan S.

1991-01-01

189

Hydrolysis of ferric ion in water and conformational equilibrium  

E-print Network

Reported here are results of theoretical calculations on the hexaaquoferric complex and deprotonated products to investigate the molecular mechanisms of hydrolysis of ferric ion in water. The combination of density functional electronic structure techniques and a dielectric continuum model for electrostatic solvation applied to the Fe(H$_2$O)$_6

Martin, R L E; Pratt, L R; Martin, Richard L.; Pratt, Lawrence R.

1998-01-01

190

Ferric Carboxymaltose in Patients with Heart Failure and Iron Deficiency  

Microsoft Academic Search

BACKGROUND Iron deficiency may impair aerobic performance. This study aimed to determine whether treatment with intravenous iron (ferric carboxymaltose) would improve symptoms in patients who had heart failure, reduced left ventricular ejection frac- tion, and iron deficiency, either with or without anemia. METHODS We enrolled 459 patients with chronic heart failure of New York Heart Association (NYHA) functional class II

Stefan D. Anker; Josep Comin Colet; Gerasimos Filippatos; Ronnie Willenheimer; Kenneth Dickstein; Helmut Drexler; Thomas F. Lüscher; Boris Bart; Waldemar Banasiak; Joanna Niegowska; Bridget-Anne Kirwan; Claudio Mori; Barbara von Eisenhart Rothe; Stuart J. Pocock; Philip A. Poole-Wilson; Piotr Ponikowski

2009-01-01

191

21 CFR 184.1296 - Ferric ammonium citrate.  

Code of Federal Regulations, 2013 CFR

...of 16.5 to 18.5 percent iron, approximately 9 percent ammonia, and 65 percent citric acid and occurs as reddish brown or garnet red scales or granules or as a brownish-yellowish powder. (2) Ferric ammonium citrate (iron (III) ammonium...

2013-04-01

192

21 CFR 184.1296 - Ferric ammonium citrate.  

...of 16.5 to 18.5 percent iron, approximately 9 percent ammonia, and 65 percent citric acid and occurs as reddish brown or garnet red scales or granules or as a brownish-yellowish powder. (2) Ferric ammonium citrate (iron (III) ammonium...

2014-04-01

193

Role of cytochrome b5 in NADH-dependent microsomal reduction of ferric complexes, lipid peroxidation, and hydrogen peroxide generation.  

PubMed

The NADH-dependent microsomal electron transfer system consists of NADH-cytochrome b5 reductase and cytochrome b5, which donates reducing equivalents to fatty acyl desaturase, cytochrome P450, and other reactions. A study was carried out to investigate the interaction of NADH with several ferric complexes and to evaluate the role of cytochrome b5 in these interactions. NADH-dependent microsomal lipid peroxidation was stimulated by ferric-ATP, ferric-histidine, and ferric-ammonium sulfate, but not by ferric-EDTA. Anti-cytochrome b5 IgG produced a concentration-dependent inhibition of lipid peroxidation catalyzed by all three ferric complexes. Addition of purified cytochrome b5 to the microsomes increased the rate of lipid peroxidation with all three ferric complexes. Lipid peroxidation in control and the cytochrome b5-fortified microsomes was not sensitive to superoxide dismutase, catalase, or DMSO and was completely inhibited by trolox and propylgallate. Ferric-EDTA stimulated NADH-dependent microsomal production of H2O2 and NADH consumption. Anti-cytochrome b5 IgG had only a small inhibitory effect on this stimulation by ferric-EDTA. NADH supported microsomal reduction of ferric complexes in the order ferric-ATP > ferric-histidine approximately ferric-ammonium sulfate > ferric-EDTA. Anti-cytochrome b5 IgG inhibited, whereas added cytochrome b5 stimulated, the reduction of ferric-ATP, ferric-histidine, and ferric-ammonium sulfate, whereas reduction of ferric-EDTA was not affected by these additions. Ferric-ATP, at high concentrations, was more effective than ferric-histidine or ferric-ammonium sulfate in stimulating lipid peroxidation and in becoming reduced by NADH-dependent microsomal electron transport; anti-cytochrome b5 IgG was less inhibitory and added b5 was less stimulatory at 50 microM ferric-ATP compared to 5 microM ferric-ATP or 50 microM ferric-histidine or 50 microM ferric-ammonium sulfate. It is concluded that cytochrome b5 is required for reduction of low and high concentrations of ferric-histidine and ferric-ammonium sulfate and low concentrations of ferric-ATP and for the lipid peroxidation catalyzed by these ferric complexes. The reductase, not cytochrome b5, is involved in interaction with ferric-EDTA. Higher concentrations of ferric-ATP can also interact with the reductase, as well as with cytochrome b5. PMID:8554320

Yang, M X; Cederbaum, A I

1995-12-20

194

Structural Characterization of Ferric Hemoglobins from Three Antarctic Fish Species of the Suborder Notothenioidei  

PubMed Central

Spontaneous autoxidation of tetrameric Hbs leads to the formation of Fe (III) forms, whose physiological role is not fully understood. Here we report structural characterization by EPR of the oxidized states of tetrameric Hbs isolated from the Antarctic fish species Trematomus bernacchii, Trematomus newnesi, and Gymnodraco acuticeps, as well as the x-ray crystal structure of oxidized Trematomus bernacchii Hb, redetermined at high resolution. The oxidation of these Hbs leads to formation of states that were not usually detected in previous analyses of tetrameric Hbs. In addition to the commonly found aquo-met and hydroxy-met species, EPR analyses show that two distinct hemichromes coexist at physiological pH, referred to as hemichromes I and II, respectively. Together with the high-resolution crystal structure (1.5 Å) of T. bernacchii and a survey of data available for other heme proteins, hemichrome I was assigned by x-ray crystallography and by EPR as a bis-His complex with a distorted geometry, whereas hemichrome II is a less constrained (cytochrome b5-like) bis-His complex. In four of the five Antartic fish Hbs examined, hemichrome I is the major form. EPR shows that for HbCTn, the amount of hemichrome I is substantially reduced. In addition, the concomitant presence of a penta-coordinated high-spin Fe (III) species, to our knowledge never reported before for a wild-type tetrameric Hb, was detected. A molecular modeling investigation demonstrates that the presence of the bulkier Ile in position 67? in HbCTn in place of Val as in the other four Hbs impairs the formation of hemichrome I, thus favoring the formation of the ferric penta-coordinated species. Altogether the data show that ferric states commonly associated with monomeric and dimeric Hbs are also found in tetrameric Hbs. PMID:17545238

Vergara, Alessandro; Franzese, Marisa; Merlino, Antonello; Vitagliano, Luigi; Verde, Cinzia; di Prisco, Guido; Lee, H. Caroline; Peisach, Jack; Mazzarella, Lelio

2007-01-01

195

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

NASA Astrophysics Data System (ADS)

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.

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

2013-09-01

196

Bacillus cereus iron uptake protein fishes out an unstable ferric citrate trimer.  

PubMed

Citrate is a common biomolecule that chelates Fe(III). Many bacteria and plants use ferric citrate to fulfill their nutritional requirement for iron. Only the Escherichia coli ferric citrate outer-membrane transport protein FecA has been characterized; little is known about other ferric citrate-binding proteins. Here we report a unique siderophore-binding protein from the gram-positive pathogenic bacterium Bacillus cereus that binds multinuclear ferric citrate complexes. We have demonstrated that B. cereus ATCC 14579 takes up (55)Fe radiolabeled ferric citrate and that a protein, BC_3466 [renamed FctC (ferric citrate-binding protein C)], binds ferric citrate. The dissociation constant (K(d)) of FctC at pH 7.4 with ferric citrate (molar ratio 1:50) is 2.6 nM. This is the tightest binding observed of any B. cereus siderophore-binding protein. Nano electrospray ionization-mass spectrometry (nano ESI-MS) analysis of FctC and ferric citrate complexes or citrate alone show that FctC binds diferric di-citrate, and triferric tricitrate, but does not bind ferric di-citrate, ferric monocitrate, or citrate alone. Significantly, the protein selectively binds triferric tricitrate even though this species is naturally present at very low equilibrium concentrations. PMID:23027976

Fukushima, Tatsuya; Sia, Allyson K; Allred, Benjamin E; Nichiporuk, Rita; Zhou, Zhongrui; Andersen, Ulla N; Raymond, Kenneth N

2012-10-16

197

Bacillus cereus iron uptake protein fishes out an unstable ferric citrate trimer  

PubMed Central

Citrate is a common biomolecule that chelates Fe(III). Many bacteria and plants use ferric citrate to fulfill their nutritional requirement for iron. Only the Escherichia coli ferric citrate outer-membrane transport protein FecA has been characterized; little is known about other ferric citrate-binding proteins. Here we report a unique siderophore-binding protein from the Gram-positive pathogenic bacterium Bacillus cereus that binds multinuclear ferric citrate complexes. We have demonstrated that B. cereus ATCC 14579 takes up 55Fe radiolabeled ferric citrate and that a protein, BC_3466 [renamed FctC (ferric citrate-binding protein C)], binds ferric citrate. The dissociation constant (Kd) of FctC at pH 7.4 with ferric citrate (molar ratio 1:50) is 2.6 nM. This is the tightest binding observed of any B. cereus siderophore-binding protein. Nano electrospray ionization–mass spectrometry (nano ESI-MS) analysis of FctC and ferric citrate complexes or citrate alone show that FctC binds diferric di-citrate, and triferric tricitrate, but does not bind ferric di-citrate, ferric monocitrate, or citrate alone. Significantly, the protein selectively binds triferric tricitrate even though this species is naturally present at very low equilibrium concentrations. PMID:23027976

Fukushima, Tatsuya; Sia, Allyson K.; Allred, Benjamin E.; Nichiporuk, Rita; Zhou, Zhongrui; Andersen, Ulla N.; Raymond, Kenneth N.

2012-01-01

198

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

NASA Astrophysics Data System (ADS)

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 (15-35°C) 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.

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

2013-09-01

199

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

NASA Technical Reports Server (NTRS)

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.

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

2005-01-01

200

The disposal of radioactive ferric floc  

SciTech Connect

An iron hydroxide floc is used as treatment for adsorbing low amounts of actinides during nuclear fuel re-processing. This waste is cemented only after pre-treatment with Ca(OH){sub 2}. Characterisation of all simulant material has been undertaken using XRD, TGA and SEM/EDS. The floc is a moderately alkaline colloidal slurry containing approximately 15 wt% solids, with the main particulate being an amorphous hydrated iron oxide. The main phase formed during pre-treatment appears to be an X-ray amorphous hydrated calcium-ferrate phase. Embedded within this are small amounts of crystalline Ca(OH){sub 2}, calcite, Fe{sub 6}(OH){sub 12}(CO{sub 3}), Ca{sub 6}Fe{sub 2}(SO{sub 4}){sub 3}(OH){sub 12} . 26H{sub 2}O and Ca{sub 3}B{sub 2}O{sub 6}, and can form depending on concentrations of Ca(OH){sub 2} and time. Apart from Ca(OH){sub 2} and calcite, none of the crystalline phases detected during pre-treatment are detected when the floc is encapsulated in an OPC/PFA composite cement hydrated for 90 days. The main crystalline phase detected in the hardened wasteform is a solid solution hydrogarnet, Ca{sub 3}AlFe(SiO{sub 4})(OH){sub 8}, known as C{sub 3}(A,F)SH{sub 4} in cement chemistry nomenclature.

Collier, N.C. [Immobilisation Science Laboratory, Department of Engineering Materials, University of Sheffield, Mappin Street, Sheffield, S1 3JD (United Kingdom)]. E-mail: n.collier@sheffield.ac.uk; Milestone, N.B. [Immobilisation Science Laboratory, Department of Engineering Materials, University of Sheffield, Mappin Street, Sheffield, S1 3JD (United Kingdom); Hill, J. [Nirex Ltd., Harwell, Oxfordshire, OX11 0RH (United Kingdom); Godfrey, I.H. [Nexia Solutions, Sellafield, Seascale, Cumbria, CA20 1PG (United Kingdom)

2006-07-01

201

Pharmacokinetics of iron salts and ferric hydroxide-carbohydrate complexes.  

PubMed

Pharmacokinetic measurements of ferrous sulphate and ferric hydroxide-polymaltose complex on anaemic and non-anaemic rats have shown different postabsorption serum iron levels, invasion and elimination constants and distribution volumes for the two preparations. But nevertheless the absorption and utilization ratios of iron from both preparations are equal. It is therefore not justified to calculate utilization ratios for chemically different iron preparations on the basis of postabsorption serum iron measurements. Similar pharmacokinetic differences of these two iron preparations could also be found in clinical trials, which means that different serum iron increase results in an equal utilization ratio for both preparations. It is clear that ferrous sulphate and ferric hydroxide-polymaltose complex must have a different absorption mechanism. The postulated absorption mechanism is in agreement with all the facts known today and does explain the pharmacokinetic difference between the investigated preparations. PMID:3566862

Geisser, P; Müller, A

1987-01-01

202

Quantitative determination of cesium binding to ferric hexacyanoferrate: Prussian blue  

Microsoft Academic Search

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

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

2008-01-01

203

VOLUME 78, NUMBER 11 P H Y S I C A L R E V I E W L E T T E R S 17 MARCH 1997 Role of Ultrafine Microstructures in Dynamic Fracture in Nanophase Silicon Nitride  

E-print Network

measurements on a variety of brittle and ductile solids have revealed self-affine behavior of fracture surfaces Microstructures in Dynamic Fracture in Nanophase Silicon Nitride Rajiv K. Kalia, Aiichiro Nakano, Andrey investigate dynamic fracture in nanophase Si3N4. The simulations reveal that intercluster regions

Southern California, University of

204

Deposition rates of oxidized iron on Mars  

NASA Technical Reports Server (NTRS)

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.

Burns, R. G.

1993-01-01

205

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

PubMed

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 -2.2±0.2 mg/dl (mean±SEM) (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=899±488 ng/ml [mean±SD]; transferrin saturation=39%±17%) versus subjects on active control (ferritin=628±367 ng/ml [mean±SD]; 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

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

206

Osteoblast function on nanophase alumina materials: Influence of chemistry, phase, and topography.  

PubMed

Alumina is a material that has been used in both dental and orthopedic applications. It is with these uses in mind that osteoblast (bone-forming cell) function on alumina of varying particulate size, chemistry, and phase was tested in order to determine what formulation might be the most beneficial for bone regeneration. Specifically, in vitro osteoblast adhesion, proliferation, intracellular alkaline phosphatase activity, and calcium deposition was observed on delta-phase nanospherical, alpha-phase conventional spherical, and boehmite nanofiber alumina. Results showed for the first time increased osteoblast functions on the nanofiber alumina. Specifically, a 16% increase in osteoblast adhesion over nanophase spherical alumina and a 97% increase over conventional spherical alumina were found for nanofiber alumina after 2 h. A 29% increase in cell number after 5 days and up to a 57% greater amount of calcium was found on the surface of the nanofiber alumina compared with other alumina surfaces. Some of the possible explanations for such enhanced osteoblast behavior on nanofiber alumina may be attributed to chemistry, crystalline phase, and topography. Increased osteoblast function on nanofiber alumina suggests that it may be an ideal material for use in orthopedic and dental applications. PMID:14624515

Price, Rachel L; Gutwein, Luke G; Kaledin, Leonid; Tepper, Frederick; Webster, Thomas J

2003-12-15

207

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

PubMed Central

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

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

2013-01-01

208

Solid-solid interface adsorption of proteins and enzymes in nanophase-separated amphiphilic conetworks.  

PubMed

Amphiphilic polymer conetworks (APCNs) are materials with a very large interface between their hydrophilic and hydrophobic phases due to their nanophase-separated morphologies. Proteins were found to enrich in APCNs by up to 2 orders of magnitude when incubated in aqueous protein solutions, raising the question of the driving force of protein uptake into APCNs. The loading of poly(2-hydroxyethyl acrylate)-linked by-poly(dimethylsiloxane) (PHEA-l-PDMS) with heme proteins (myoglobin, horseradish peroxidase, hemoglobin) and lipases was studied under variation of parameters such as incubation time, pH, concentration of the protein solution, and conetwork composition. Adsorption of enzymes to the uncharged interface is the main reason for protein uptake, resulting in protein loading of up to 23 wt %. Experimental results were supported by computation of electrostatic potential maps of a lipase, indicating that hydrophobic patches are responsible for the adsorption to the interface. The findings underscore the potential of enzyme-loaded APCNs in biocatalysis and as sensors. PMID:21413720

Dech, Stephan; Cramer, Tobias; Ladisch, Reinhild; Bruns, Nico; Tiller, Joerg C

2011-05-01

209

Performance comparison of Fenton process, ferric coagulation and H 2O 2\\/pyridine\\/Cu(II) system for decolorization of Remazol Turquoise Blue G-133  

Microsoft Academic Search

This paper evaluates the Fenton process (involving oxidation and coagulation), ferric coagulation and H2O2\\/pyridine\\/Cu(II) system for the removal of color from a synthetic textile wastewater containing polyvinyl alcohol and a reactive dyestuff, Remazol Turquoise Blue G-133. Experiments were conducted to investigate the effects of operating variables such as pH, coagulant dose, polyelectrolyte type, H2O2 and Fe(II) concentrations, optimum pyridine and

Ulusoy Bali; Bünyamin Karagözo?lu

2007-01-01

210

Mössbauer mineralogy of rock, soil, and dust at Meridiani Planum, Mars: Opportunity's journey across sulfate-rich outcrop, basaltic sand and dust, and hematite lag deposits  

Microsoft Academic Search

The Mössbauer (MB) spectrometer on Opportunity measured the Fe oxidation state, identified Fe-bearing phases, and measured relative abundances of Fe among those phases at Meridiani Planum, Mars. Eight Fe-bearing phases were identified: jarosite (K,Na,H3O)(Fe,Al)(OH)6(SO4)2, hematite, olivine, pyroxene, magnetite, nanophase ferric oxides (npOx), an unassigned ferric phase, and metallic Fe (kamacite). Burns Formation outcrop rocks consist of hematite-rich spherules dispersed throughout

R. V. Morris; G. Klingelhöfer; C. Schröder; D. S. Rodionov; A. Yen; D. W. Ming; P. A. de Souza; T. Wdowiak; I. Fleischer; R. Gellert; B. Bernhardt; U. Bonnes; B. A. Cohen; E. N. Evlanov; J. Foh; P. Gütlich; E. Kankeleit; T. McCoy; D. W. Mittlefehldt; F. Renz; M. E. Schmidt; B. Zubkov; S. W. Squyres; R. E. Arvidson

2006-01-01

211

Ferric carboxymaltose-mediated attenuation of Doxorubicin-induced cardiotoxicity in an iron deficiency rat model.  

PubMed

Since anthracycline-induced cardiotoxicity (AIC), a complication of anthracycline-based chemotherapies, is thought to involve iron, concerns exist about using iron for anaemia treatment in anthracycline-receiving cancer patients. This study evaluated how intravenous ferric carboxymaltose (FCM) modulates the influence of iron deficiency anaemia (IDA) and doxorubicin (3-5?mg per kg body weight [BW]) on oxidative/nitrosative stress, inflammation, and cardiorenal function in spontaneously hypertensive stroke-prone (SHR-SP) rats. FCM was given as repeated small or single total dose (15?mg iron per kg BW), either concurrent with or three days after doxorubicin. IDA (after dietary iron restriction) induced cardiac and renal oxidative stress (markers included malondialdehyde, catalase, Cu,Zn-superoxide dismutase, and glutathione peroxidase), nitrosative stress (inducible nitric oxide synthase and nitrotyrosine), inflammation (tumour necrosis factor-alpha and interleukin-6), and functional/morphological abnormalities (left ventricle end-diastolic and end-systolic diameter, fractional shortening, density of cardiomyocytes and capillaries, caveolin-1 expression, creatinine clearance, and urine neutrophil gelatinase-associated lipocalin) that were aggravated by doxorubicin. Notably, iron treatment with FCM did not exacerbate but attenuated the cardiorenal effects of IDA and doxorubicin independent of the iron dosing regimen. The results of this model suggest that intravenous FCM can be used concomitantly with an anthracycline-based chemotherapy without increasing signs of AIC. PMID:24876963

Toblli, Jorge Eduardo; Rivas, Carlos; Cao, Gabriel; Giani, Jorge Fernando; Funk, Felix; Mizzen, Lee; Dominici, Fernando Pablo

2014-01-01

212

Ferric Carboxymaltose-Mediated Attenuation of Doxorubicin-Induced Cardiotoxicity in an Iron Deficiency Rat Model  

PubMed Central

Since anthracycline-induced cardiotoxicity (AIC), a complication of anthracycline-based chemotherapies, is thought to involve iron, concerns exist about using iron for anaemia treatment in anthracycline-receiving cancer patients. This study evaluated how intravenous ferric carboxymaltose (FCM) modulates the influence of iron deficiency anaemia (IDA) and doxorubicin (3–5?mg per kg body weight [BW]) on oxidative/nitrosative stress, inflammation, and cardiorenal function in spontaneously hypertensive stroke-prone (SHR-SP) rats. FCM was given as repeated small or single total dose (15?mg iron per kg BW), either concurrent with or three days after doxorubicin. IDA (after dietary iron restriction) induced cardiac and renal oxidative stress (markers included malondialdehyde, catalase, Cu,Zn-superoxide dismutase, and glutathione peroxidase), nitrosative stress (inducible nitric oxide synthase and nitrotyrosine), inflammation (tumour necrosis factor-alpha and interleukin-6), and functional/morphological abnormalities (left ventricle end-diastolic and end-systolic diameter, fractional shortening, density of cardiomyocytes and capillaries, caveolin-1 expression, creatinine clearance, and urine neutrophil gelatinase-associated lipocalin) that were aggravated by doxorubicin. Notably, iron treatment with FCM did not exacerbate but attenuated the cardiorenal effects of IDA and doxorubicin independent of the iron dosing regimen. The results of this model suggest that intravenous FCM can be used concomitantly with an anthracycline-based chemotherapy without increasing signs of AIC. PMID:24876963

Toblli, Jorge Eduardo; Rivas, Carlos; Cao, Gabriel; Giani, Jorge Fernando; Dominici, Fernando Pablo

2014-01-01

213

Comparison of ferric iron generation by different species of acidophilic bacteria immobilized in packed-bed reactors.  

PubMed

Flooded packed-bed bioreactors, prepared by immobilizing four different species of acidophilic iron-oxidizing bacteria on porous glass beads, were compared for their ferric iron-generating capacities when operated in batch and continuous flow modes over a period of up to 9 months, using a ferrous iron-rich synthetic liquor and acid mine drainage (AMD) water. The bacteria used were strains of Acidithiobacillus ferrooxidans, Leptospirillum ferrooxidans, a Ferrimicrobium-like isolate (TSTR) and a novel Betaproteobacterium (isolate PSTR), which were all isolated from relatively low-temperature mine waters. Three of the bacteria used were chemoautotrophs, while the Ferrimicrobium isolate was an obligate heterotroph. Greater biomass yields achievable with the Ferrimicrobium isolate resulted in greater iron oxidation efficiency in the newly commissioned bioreactor containing this bacterium, though long-term batch testing with organic carbon-free solution resulted in similar maximum iron oxidation rates in all four bioreactors. Two of the bioreactors (those containing immobilized L. ferrooxidans and Ferrimicrobium TSTR) were able to generate significantly lower concentrations of ferrous iron than the others when operated in batch mode. In contrast, when operated as continuous flow systems, the bioreactor containing immobilized PSTR was superior to the other three when challenged with either synthetic or actual AMD at high flow rates. The least effective bacterium overall was At. ferrooxidans, which has previously been the only iron-oxidizer used in the majority of reports describing ferric iron-generating bioreactors. The results of these experiments showed that different species of iron-oxidizing acidophiles have varying capacities to oxidize ferrous iron when immobilized in packed-bed bioreactors, and that novel isolates may be superior to well-known species. PMID:17983721

Rowe, Owen F; Johnson, D Barrie

2008-03-01

214

Environ. Scl. Technol. W84, 18, 860-868 Photoreductive Dissolution of Colloidal Iron Oxides in Natural Waters  

E-print Network

and oxide-bound ferric citrate complexes and the known photoactivity of soluble iron- fulvic acid groups (II/or dissolutionof colloidaliron oxides (8). All of these natural water studies have been performed in acidic lakes

Morel, FranƧois M. M.

215

Ferric hydroxide and ferric hydroxysulfate precipitation by bacteria in an acid mine drainage lagoon  

E-print Network

the oxidation of ferrous iron with or without the presence of sulfate. However, our study of bacterial incorporated into the mineralised matrix. In the subsurface, more cells were associated with granular, fine provide a natural solution to cleansing acidified waters with a high dissolved metal content. Keywords

Konhauser, Kurt

216

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...

217

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

PubMed

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

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

2014-11-19

218

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

NASA Astrophysics Data System (ADS)

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 ?. 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, ? \\lt 0.0701 u (b) transition regime, 0.0701 u?slant ? ?slant 0.0916 u and (c) thick coating regime, ? \\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 ? \\lt 7.0 \\text{nm} transition regime, 7.0\\lt? \\lt 9.2 \\text{nm} and thick coating, ? \\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%.

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

2014-11-01

219

Reaction mechanism for the ferric chloride leaching of sphalerite  

NASA Astrophysics Data System (ADS)

Reaction mechanisms for the ferric chloride leaching of sphalerite are proposed based on data obtained in leaching and dual cell experiments presented in this work and in a previous study. The results from the leaching experiments show that at low concentrations the rate is proportional to [Fe3+]T 0.5 and [Cl-]T 0.43 but at higher concentrations the reaction order with respect to both [Fe3+]T and [Cl-]T decreases. Using dual cell experiments which allow the half cell reactions to be separated, increased rates are observed when NaCl is added to the anolyte and to the catholyte. The increase in rate is attributed to a direct, anodic electrochemical reaction of Cl- with the mineral. When NaCl is added only to the catholyte, a decrease in the rate is observed due to a decrease in the E 0 of the cathode which is attributed to the formation of ferric-chloro complexes. Several possible electrochemical mechanisms and mathematical models based on the Butler-Volmer relation are delineated, and of these, one model is selected which accounts for the experimentally observed changes in reaction order for both Fe3+ and Cl-. This analysis incorporates a charge transfer process for each ion and an adsorption step for ferric and chloride ions. The inhibiting effect of Fe2+ noted by previous investigators is also accounted for through a similar model which includes back reaction kinetics for Fe2+. The proposed models successfully provide a theoretical basis for describing the role of Cl-, Fe3+, and Fe2+ as well as their interrelationship in zinc sulfide leaching reactions. Possible applications of these results to chloride leaching systems involving other sulfides or complex sulfides are considered.

Warren, G. W.; Henein, H.; Jin, Zuo-Mei

1985-12-01

220

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

PubMed

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

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

2014-07-01

221

Redox potential measurements and Mössbauer spectrometry of Fe II adsorbed onto Fe III (oxyhydr)oxides  

Microsoft Academic Search

The redox properties of FeII adsorbed onto a series of FeIII (oxyhydr)oxides (goethite, lepidocrocite, nano-sized ferric oxide hydrate (nano-FOH), and hydrous ferric oxide (HFO)) have been investigated by rest potential measurements at a platinum electrode, as a function of pH (?log10[H+]) and surface coverage. Using the constant capacitance surface complexation model to describe FeII adsorption onto these substrates, theoretical values

Ewen Silvester; Laurent Charlet; Christophe Tournassat; Antoine Géhin; Jean-Marc Grenčche; Emmanuelle Liger

2005-01-01

222

Biogenic catalysis of soil formation on Mars?  

NASA Technical Reports Server (NTRS)

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.

Bishop, J. L.

1998-01-01

223

Biogenic Catalysis of Soil Formation on Mars?  

NASA Astrophysics Data System (ADS)

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.

Bishop, Janice L.

1998-10-01

224

Ferric carboxymaltose: a review of its use in iron-deficiency anaemia.  

PubMed

Ferric carboxymaltose (Ferinject(R)), a novel iron complex that consists of a ferric hydroxide core stabilized by a carbohydrate shell, allows for controlled delivery of iron to target tissues. Administered intravenously, it is effective in the treatment of iron-deficiency anaemia, delivering a replenishment dose of up to 1000 mg of iron during a minimum administration time of ferric carboxymaltose rapidly improves haemoglobin levels and replenishes depleted iron stores in various populations of patients with iron-deficiency anaemia, including those with inflammatory bowel disease, heavy uterine bleeding, postpartum iron-deficiency anaemia or chronic kidney disease. It was well tolerated in clinical trials. Ferric carboxymaltose is, therefore, an effective option in the treatment of iron-deficiency anaemia in patients for whom oral iron preparations are ineffective or cannot be administered. Ferric carboxymaltose is a macromolecular ferric hydroxide carbohydrate complex, which allows for controlled delivery of iron within the cells of the reticuloendothelial system and subsequent delivery to the iron-binding proteins ferritin and transferrin, with minimal risk of release of large amounts of ionic iron in the serum. Intravenous administration of ferric carboxymaltose results in transient elevations in serum iron, serum ferritin and transferrin saturation, and, ultimately, in the correction of haemoglobin levels and replenishment of depleted iron stores. The total iron concentration in the serum increased rapidly in a dose-dependent manner after intravenous administration of ferric carboxymaltose. Ferric carboxymaltose is rapidly cleared from the circulation and is distributed primarily to the bone marrow ( approximately 80%) and also to the liver and spleen. Repeated weekly administration of ferric carboxymaltose does not result in accumulation of transferrin iron in patients with iron-deficiency anaemia. Intravenously administered ferric carboxymaltose was effective in the treatment of iron-deficiency anaemia in several 6- to 12-week, randomized, open-label, controlled, multicentre trials in various patient populations, including those with inflammatory bowel disease, heavy uterine bleeding or postpartum iron-deficiency anaemia, and those with chronic kidney disease not undergoing or undergoing haemodialysis. In most trials, patients received either ferric carboxymaltose equivalent to an iron dose of ferric carboxymaltose or iron sucrose administered into the haemodialysis line two to three times weekly. In all trials, ferric carboxymaltose was administered until each patient had received his or her calculated total iron replacement dose. Haemoglobin-related outcomes improved in patients with iron-deficiency anaemia receiving ferric carboxymaltose. Treatment with ferric carboxymaltose was associated with rapid and sustained increases from baseline in haemoglobin levels. Ferric carboxymaltose was considered to be as least as effective as ferrous sulfate with regard to changes from baseline in haemoglobin levels or the proportion of patients achieving a haematopoietic response at various timepoints. In general, improvements in haemoglobin levels were more rapid with ferric carboxymaltose than with ferrous sulfate. In patients with chronic kidney disease undergoing haemodialysis, ferric carboxymaltose was at least as effective as iron sucrose. Ferric carboxymaltose also replenished depleted iron stores and improved health-related quality-of-life (HR-QOL) in patients with iron-deficiency anaemia. Recipients of ferric carboxymaltose demonstrated improvements from b

Lyseng-Williamson, Katherine A; Keating, Gillian M

2009-01-01

225

Si quantum dots embedded in an amorphous SiC matrix: nanophase control by non-equilibrium plasma hydrogenation.  

PubMed

Nanophase nc-Si/a-SiC films that contain Si quantum dots (QDs) embedded in an amorphous SiC matrix were deposited on single-crystal silicon substrates using inductively coupled plasma-assisted chemical vapor deposition from the reactive silane and methane precursor gases diluted with hydrogen at a substrate temperature of 200 degrees C. The effect of the hydrogen dilution ratio X (X is defined as the flow rate ratio of hydrogen-to-silane plus methane gases), ranging from 0 to 10.0, on the morphological, structural, and compositional properties of the deposited films, is extensively and systematically studied by scanning electron microscopy, high-resolution transmission electron microscopy, X-ray diffraction, Raman spectroscopy, Fourier-transform infrared absorption spectroscopy, and X-ray photoelectron spectroscopy. Effective nanophase segregation at a low hydrogen dilution ratio of 4.0 leads to the formation of highly uniform Si QDs embedded in the amorphous SiC matrix. It is also shown that with the increase of X, the crystallinity degree and the crystallite size increase while the carbon content and the growth rate decrease. The obtained experimental results are explained in terms of the effect of hydrogen dilution on the nucleation and growth processes of the Si QDs in the high-density plasmas. These results are highly relevant to the development of next-generation photovoltaic solar cells, light-emitting diodes, thin-film transistors, and other applications. PMID:20644764

Cheng, Qijin; Tam, Eugene; Xu, Shuyan; Ostrikov, Kostya Ken

2010-04-01

226

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

PubMed

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

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

2008-02-21

227

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

NASA Astrophysics Data System (ADS)

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.

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

2012-12-01

228

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...

229

Organic matter mineralization with reduction of ferric iron in anaerobic sediments  

Microsoft Academic Search

The potential for ferric iron reduction with fermentable substrates, fermentation products, and complex organic matter as electron donors was investigated with sediments from freshwater and brackish water sites in the Potomac River Estuary. In enrichments with glucose and hematite, iron reduction was a minor pathway for electron flow, and fermentation products accumulated. The substitution of amorphous ferric oxyhydroxide for hematite

D. R. Lovley; E. J. P. Phillips

1986-01-01

230

The Ferric Reducing Ability of Plasma (FRAP) as a Measure of “Antioxidant Power”: The FRAP Assay  

Microsoft Academic Search

A simple, automated test measuring the ferric reducing ability of plasma, the FRAP assay, is presented as a novel method for assessing “antioxidant power.” Ferric to ferrous ion reduction at low pH causes a colored ferrous-tripyridyltriazine complex to form. FRAP values are obtained by comparing the absorbance change at 593 nm in test reaction mixtures with those containing ferrous ions

Iris F. F. Benzie; J. J. Strain

1996-01-01

231

Perturbation-Response Scanning Reveals Ligand Entry-Exit Mechanisms of Ferric Binding Protein  

Microsoft Academic Search

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

Canan Atilgan; Ali Rana Atilgan

2009-01-01

232

Perturbation-Response Scanning Reveals Ligand Entry-Exit Mechanisms of Ferric Binding Protein  

Microsoft Academic Search

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

Canan Atilgan; Ali Rana Atilgan

2009-01-01

233

The effects of nanophase ceramic materials on select functions of human mesenchymal stem cells  

NASA Astrophysics Data System (ADS)

Modification of the chemistry and surface topography of nanophase ceramics can provide biomaterial formulations capable of directing the functions of adherent cells. This effect relies on the type, amount, and conformation of adsorbed proteins that mediate the adhesion of mesenchymally-descended lineages. The mechanisms driving this response are not yet well-understood and have not been investigated for human mesenchymal stem cells (HMSCs), a progenitor-lineage critical to orthopaedic biomaterials. The present study addressed these needs by examining the in vitro adhesion, proliferation, and osteogenic differentiation of HMSCs as a function of substrate chemistry and grain size, with particular attention to the protein-mediated mechanisms of cell adhesion. Alumina, titania, and hydroxyapatite substrates were prepared with 1500, 200, 50, and 24 (alumina only) nm grain sizes, and characterized with respect to surface properties, porosity, composition, and phase. Adhesion of HMSCs was dependent upon both chemistry and grain size. Specifically, adhesion on alumina and hydroxyapatite was reduced on 50 and 24 (alumina only) nm surfaces, as compared to 1500 and 200 nm surfaces, while adhesion on titania substrates was independent of grain size. Investigation into the protein-mediated mechanisms of this response identified vitronectin as the dominant adhesive protein, demonstrated random protein distribution across the substrate surface without aggregation or segregation, and confirmed the importance of the type, amount, and conformation of adsorbed proteins in cell adhesion. Minimal cell proliferation was observed on 50 and 24 (alumina only) nm substrates of any chemistry. Furthermore, cell proliferation was up-regulated on 200 nm substrates after 7 days of culture. Osteogenic differentiation was not detected on 50 nm substrates throughout the 28 day culture period. In contrast, osteogenic differentiation was strongly enhanced on 200 nm substrates, occurring approximately 7 days earlier and in greater magnitude than that observed on 1500 nm substrates. In summary, the current study elucidated the chemical and topographical cues necessary to optimize the vitronectin-mediated adhesion, proliferation, and differentiation of human mesenchymal stem cells on ceramic surfaces. These results expand the understanding of surface-mediated cell functions and provide information pertinent to the design of next-generation orthopaedic and tissue engineering biomaterials.

Dulgar-Tulloch, Aaron Joseph

2005-11-01

234

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

PubMed Central

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

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

2014-01-01

235

Synchrotron Characterization of Hydrogen and Ferric Iron in Martian Meteorites  

NASA Technical Reports Server (NTRS)

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.

Dyar, Melinda D.

2003-01-01

236

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

NASA Technical Reports Server (NTRS)

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.

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

1993-01-01

237

NOM removal by adsorption onto granular ferric hydroxide: Equilibrium, kinetics, filter and regeneration studies.  

PubMed

Adsorption onto granular ferric hydroxide (GFH) with subsequent in-situ regeneration is studied as a new process for natural organic matter (NOM) removal from groundwater. Adsorbent equilibrium loadings of 10-30 mgDOC g(-1)GFH(-1) are obtained, whereas the non-adsorbable DOC fraction amounts to 1.5 mgL(-1) for all investigated groundwaters. The larger and UV-active NOM fractions (mainly fulvic acids) are well adsorbed while the smaller molecular fractions are poorly or not adsorbed. However, kinetic studies show that the smaller and medium-sized fulvic acids are removed first. The equilibrium is strongly dependent on pH but only weakly on ionic strength, pointing to ligand exchange as the dominant adsorption mechanism. With regard to NOM structure, prerequisites for adsorption onto GFH are both a minimum number of functional groups and a molecular size small enough to enter the GFH pores. NOM breakthrough curves are successfully simulated using the LDF model (homogeneous surface diffusion model (HSDM) with linear driving force approach for surface diffusion) and experimentally determined mass transfer coefficients. Regeneration of loaded GFH is possible either by use of NaOH or oxidatively by H(2)O(2). The optimal quantities and concentrations are determined. PMID:17681584

Genz, Arne; Baumgarten, Benno; Goernitz, Mandy; Jekel, Martin

2008-01-01

238

Pulpal tissue reaction to formocresol vs. ferric sulfate in pulpotomized rat teeth.  

PubMed

The purpose of this study was to assess histologically the pulpal healing process after pulpotomies in rat teeth were done using two different agents: 20% dilution of formocresol (FMC) and ferric sulfate (FS). Two criteria were used: degree of inflammation and extent of pulpal involvement. Zinc oxide-eugenol paste (ZOE) or polycarboxylate cement (PCX) were placed to seal the cavity preparations. The maxillary first molars of 120 Sprague-Dawley rats were treated in this study and were divided into four groups: 1) FMC + ZOE, 2) FS + PCX, 3) FMC + PCX, and 4) FS + ZOE. After treatment the animals were sacrificed at weekly intervals for four weeks and pulpal response was evaluated according to the degree of inflammation. Other criteria were also evaluated: dentinal bridge formation, reparative dentin and odontoblastic layer. A Friedman test was performed to compare the results and find out if any differences could be found. FMC + ZOE group showed the least pulpal inflammation response, and the use of FS as an alternative agent for pulpotomies did not improve pulpal response. PMID:9484135

Cotes, O; Boj, J R; Canalda, C; Carreras, M

1997-01-01

239

Characterization of the quinone reductase activity of the ferric reductase B protein from Paracoccus denitrificans.  

PubMed

The ferric reductase B (FerB) protein of Paracoccus denitrificans exhibits activity of an NAD(P)H: Fe(III) chelate, chromate and quinone oxidoreductase. Sequence analysis places FerB in a family of soluble flavin-containing quinone reductases. The enzyme reduces a range of quinone substrates, including derivatives of 1,4-benzoquinone and 1,2- and 1,4-naphthoquinone, via a ping-pong kinetic mechanism. Dicoumarol and Cibacron Blue 3GA are competitive inhibitors of NADH oxidation. In the case of benzoquinones, FerB apparently acts through a two-electron transfer process, whereas in the case of naphthoquinones, one-electron reduction takes place resulting in the formation of semiquinone radicals. A ferB mutant strain exhibited an increased resistance to 1,4-naphthoquinone, attributable to the absence of the FerB-mediated redox cycling. The ferB promoter displayed a high basal activity throughout the growth of P. denitrificans, which could not be further enhanced by addition of different types of naphthoquinones. This indicates that the ferB gene is expressed constitutively. PMID:19138657

Sedlįcek, Vojtech; van Spanning, Rob J M; Kucera, Igor

2009-03-01

240

Binding of Ferric Enterobactin by the Escherichia coli Periplasmic Protein FepB  

PubMed Central

The periplasmic protein FepB of Escherichia coli is a component of the ferric enterobactin transport system. We overexpressed and purified the binding protein 23-fold from periplasmic extracts by ammonium sulfate precipitation and chromatographic methods, with a yield of 20%, to a final specific activity of 15,500 pmol of ferric enterobactin bound/mg. Periplasmic fluid from cells overexpressing the binding protein adsorbed catecholate ferric siderophores with high affinity: in a gel filtration chromatography assay the Kd of the ferric enterobactin-FepB binding reaction was approximately 135 nM. Intrinsic fluorescence measurements of binding by the purified protein, which were more accurate, showed higher affinity for both ferric enterobactin (Kd = 30 nM) and ferric enantioenterobactin (Kd = 15 nM), the left-handed stereoisomer of the natural E. coli siderophore. Purified FepB also adsorbed the apo-siderophore, enterobactin, with comparable affinity (Kd = 60 nM) but did not bind ferric agrobactin. Polyclonal rabbit antisera and mouse monoclonal antibodies raised against nearly homogeneous preparations of FepB specifically recognized it in solid-phase immunoassays. These sera enabled the measurement of the FepB concentration in vivo when expressed from the chromosome (4,000 copies/cell) or from multicopy plasmids (>100,000 copies/cell). Overexpression of the binding protein did not enhance the overall affinity or rate of ferric enterobactin transport, supporting the conclusion that the rate-limiting step of ferric siderophore uptake through the cell envelope is passage through the outer membrane. PMID:10986237

Sprencel, Cathy; Cao, Zhenghua; Qi, Zengbiao; Scott, Daniel C.; Montague, Marjorie A.; Ivanoff, Nora; Xu, Jide; Raymond, Kenneth M.; Newton, Salete M. C.; Klebba, Phillip E.

2000-01-01

241

Binding of ferric enterobactin by the Escherichia coli periplasmic protein FepB.  

PubMed

The periplasmic protein FepB of Escherichia coli is a component of the ferric enterobactin transport system. We overexpressed and purified the binding protein 23-fold from periplasmic extracts by ammonium sulfate precipitation and chromatographic methods, with a yield of 20%, to a final specific activity of 15,500 pmol of ferric enterobactin bound/mg. Periplasmic fluid from cells overexpressing the binding protein adsorbed catecholate ferric siderophores with high affinity: in a gel filtration chromatography assay the K(d) of the ferric enterobactin-FepB binding reaction was approximately 135 nM. Intrinsic fluorescence measurements of binding by the purified protein, which were more accurate, showed higher affinity for both ferric enterobactin (K(d) = 30 nM) and ferric enantioenterobactin (K(d) = 15 nM), the left-handed stereoisomer of the natural E. coli siderophore. Purified FepB also adsorbed the apo-siderophore, enterobactin, with comparable affinity (K(d) = 60 nM) but did not bind ferric agrobactin. Polyclonal rabbit antisera and mouse monoclonal antibodies raised against nearly homogeneous preparations of FepB specifically recognized it in solid-phase immunoassays. These sera enabled the measurement of the FepB concentration in vivo when expressed from the chromosome (4,000 copies/cell) or from multicopy plasmids (>100,000 copies/cell). Overexpression of the binding protein did not enhance the overall affinity or rate of ferric enterobactin transport, supporting the conclusion that the rate-limiting step of ferric siderophore uptake through the cell envelope is passage through the outer membrane. PMID:10986237

Sprencel, C; Cao, Z; Qi, Z; Scott, D C; Montague, M A; Ivanoff, N; Xu, J; Raymond, K M; Newton, S M; Klebba, P E

2000-10-01

242

Mössbauer and infrared spectroscopy as a diagnostic tool for the characterization of ferric tannates  

NASA Astrophysics Data System (ADS)

Fourier transform infrared spectroscopy and Mössbauer 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. Mössbauer 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.

Jaén, Juan A.; Navarro, César

2009-07-01

243

Use of ferric-impregnated volcanic ash for arsenate (V) adsorption from contaminated water with various mineralization degrees.  

PubMed

Ferric-impregnated volcanic ash (FVA) which consisted mainly of different forms of iron and aluminum oxide minerals was developed for arsenate (V) removal from an aqueous medium. The adsorption experiments were conducted in both DI water samples and actual water (Lake Kasumigaura, Japan) to investigate the effects of solution mineralization degree on the As(V) removal. Kinetic and equilibrium studies conducted in actual water revealed that the mineralization of water greatly elevated the As(V) adsorption on FVA. The experiment performed in DI water indicated that the existence of multivalence metallic cations significantly enhanced the As(V) adsorption ability, whereas competing anions such as fluoride and phosphate greatly decreased the As(V) adsorption. It is suggested that FVA is a cost-effective adsorbent for As(V) removal in low-level phosphate and fluoride solution. It was important to conduct the batch experiment using the actual water to investigate the arsenic removal on adsorbents. PMID:20974472

Chen, Rongzhi; Zhang, Zhenya; Yang, Yingnan; Lei, Zhongfang; Chen, Nan; Guo, Xu; Zhao, Chao; Sugiura, Norio

2011-01-15

244

Formation, aggregation and reactivity of amorphous ferric oxyhydroxides on dissociation of Fe(III)-organic complexes in dilute aqueous suspensions  

NASA Astrophysics Data System (ADS)

While chemical reactions that take place at the surface of amorphous ferric oxides (AFO) are known to be important in aquatic systems, incorporation of these reactions into kinetic models is hindered by a lack of ability to reliably quantify the reactivity of the surface and the changes in reactivity that occur over time. Long term decreases in the reactivity of iron oxides may be considered to result from changes in the molecular structure of the solid, however, over shorter time scales where substantial aggregation may occur, the mechanisms of reactivity loss are less clear. Precipitation of AFO may be described as a combination of homogeneous and heterogeneous reactions, however, despite its potentially significant role, the latter reaction is usually neglected in kinetic models of aquatic processes. Here, we investigate the role of AFO in scavenging dissolved inorganic ferric (Fe(III)) species (Fe') via the heterogeneous precipitation reaction during the net dissociation of organically complexed Fe(III) in seawater. Using sulfosalicylic acid (SSA) as a model ligand, AFO was shown to play a significant role in inducing the net dissociation of the Fe-SSA complexes with equations describing both the heterogeneous precipitation reaction and the aging of AFO being required to adequately describe the experimental data. An aggregation based mechanism provided a good description of AFO aging over the short time scale of the experiments. The behaviour of AFO described here has implications for the bioavailability of iron in natural systems as a result of reactions involving AFO which are recognised to occur over time scales of minutes, including adsorption of Fe' and AFO dissolution, precipitation and ageing.

Bligh, Mark W.; Waite, T. David

2010-10-01

245

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

PubMed

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

Santiago, Palacios

2012-01-01

246

Selectivity of ferric enterobactin binding and cooperativity of transport in gram-negative bacteria.  

PubMed

The ligand-gated outer membrane porin FepA serves Escherichia coli as the receptor for the siderophore ferric enterobactin. We characterized the ability of seven analogs of enterobactin to supply iron via FepA by quantitatively measuring the binding and transport of their 59Fe complexes. The experiments refuted the idea that chirality of the iron complex affects its recognition by FepA and demonstrated the necessity of an unsubstituted catecholate coordination center for binding to the outer membrane protein. Among the compounds we tested, only ferric enantioenterobactin, the synthetic, left-handed isomer of natural enterobactin, and ferric TRENCAM, which substitutes a tertiary amine for the macrocyclic lactone ring of ferric enterobactin but maintains an unsubstituted catecholate iron complex, were recognized by FepA (Kd approximately 20 nM). Ferric complexes of other analogs (TRENCAM-3,2-HOPO; TREN-Me-3,2-HOPO; MeMEEtTAM; MeME-Me-3,2-HOPO; K3MECAMS; agrobactin A) with alterations to the chelating groups and different net charge on the iron center neither adsorbed to nor transported through FepA. We also compared the binding and uptake of ferric enterobactin by homologs of FepA from Bordetella bronchisepticus, Pseudomonas aeruginosa, and Salmonella typhimurium in the native organisms and as plasmid-mediated clones expressed in E. coli. All the transport proteins bound ferric enterobactin with high affinity (Kd /=50 pmol/min/10(9) cells) in their own particular membrane environments. However, the FepA and IroN proteins of S. typhimurium failed to efficiently function in E. coli. For E. coli, S. typhimurium, and P. aeruginosa, the rate of ferric enterobactin uptake was a sigmoidal function of its concentration, indicating a cooperative transport reaction involving multiple interacting binding sites on FepA. PMID:9852016

Thulasiraman, P; Newton, S M; Xu, J; Raymond, K N; Mai, C; Hall, A; Montague, M A; Klebba, P E

1998-12-01

247

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

PubMed Central

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

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

1988-01-01

248

Selectivity of Ferric Enterobactin Binding and Cooperativity of Transport in Gram-Negative Bacteria  

PubMed Central

The ligand-gated outer membrane porin FepA serves Escherichia coli as the receptor for the siderophore ferric enterobactin. We characterized the ability of seven analogs of enterobactin to supply iron via FepA by quantitatively measuring the binding and transport of their 59Fe complexes. The experiments refuted the idea that chirality of the iron complex affects its recognition by FepA and demonstrated the necessity of an unsubstituted catecholate coordination center for binding to the outer membrane protein. Among the compounds we tested, only ferric enantioenterobactin, the synthetic, left-handed isomer of natural enterobactin, and ferric TRENCAM, which substitutes a tertiary amine for the macrocyclic lactone ring of ferric enterobactin but maintains an unsubstituted catecholate iron complex, were recognized by FepA (Kd ? 20 nM). Ferric complexes of other analogs (TRENCAM-3,2-HOPO; TREN-Me-3,2-HOPO; MeMEEtTAM; MeME-Me-3,2-HOPO; K3MECAMS; agrobactin A) with alterations to the chelating groups and different net charge on the iron center neither adsorbed to nor transported through FepA. We also compared the binding and uptake of ferric enterobactin by homologs of FepA from Bordetella bronchisepticus, Pseudomonas aeruginosa, and Salmonella typhimurium in the native organisms and as plasmid-mediated clones expressed in E. coli. All the transport proteins bound ferric enterobactin with high affinity (Kd ? 100 nM) and transported it at comparable rates (?50 pmol/min/109 cells) in their own particular membrane environments. However, the FepA and IroN proteins of S. typhimurium failed to efficiently function in E. coli. For E. coli, S. typhimurium, and P. aeruginosa, the rate of ferric enterobactin uptake was a sigmoidal function of its concentration, indicating a cooperative transport reaction involving multiple interacting binding sites on FepA. PMID:9852016

Thulasiraman, Padmamalini; Newton, Salete M. C.; Xu, Jide; Raymond, Kenneth N.; Mai, Christine; Hall, Angela; Montague, Marjorie A.; Klebba, Phillip E.

1998-01-01

249

Ferrous iron oxidation by anoxygenic phototrophic bacteria  

Microsoft Academic Search

NATURAL oxidation of ferrous to ferric iron by bacteria such as Thiobacillus ferrooxidans or Gallionella ferruginea1, or by chemical oxidation2,3 has previously been thought always to involve molecular oxygen as the electron acceptor. Anoxic photochemical reactions4-6 or a photobiological process involving two photosystems7-9 have also been discussed as mechanisms of ferrous iron oxidation. The knowledge of such processes has implications

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

1993-01-01

250

Ferric Leghemoglobin in Plant-Attached Leguminous Nodules.  

PubMed

Leghemoglobin (Lb) is essential for nitrogen fixation by intact leguminous nodules. To determine whether ferric Lb (Lb3+) was detectable in nodules under normal or stressed conditions, we monitored the status of Lb in intact nodules attached to sweet clover (Melilotus officinalis) and soybean (Glycine max [L.] Merr.) roots exposed to various conditions. The effects of N2 and O2 streams and elevated nicotinate levels on root-attached nodules were tested to determine whether the spectrophotometric technique was showing the predicted responses of Lb. The soybean and sweet clover nodules' Lb spectra indicated predominantly ferrous Lb and LbO2 in young (34 d) plants. As the nodule aged beyond 45 d, it was possible to induce Lb3+ with a 100% O2 stream (15 min). At 65 d without inducement, the nodule Lb status indicated the presence of some Lb3+ along with ferrous Lb and oxyferrous Lb. Nicotinate and fluoride were used as ligands to identify Lb3+. Computer-calculated difference spectra were used to demonstrate the changes in Lb spectra under different conditions. Some conditions that increased absorbance in the 626 nm region (indicating Lb3+ accumulation) were root-fed ascorbate and dehydroascorbate, plant exposure to darkness, and nodule water immersion. PMID:12228593

Lee, Kk.; Shearman, L. L.; Erickson, B. K.; Klucas, R. V.

1995-09-01

251

Ferric Leghemoglobin in Plant-Attached Leguminous Nodules.  

PubMed Central

Leghemoglobin (Lb) is essential for nitrogen fixation by intact leguminous nodules. To determine whether ferric Lb (Lb3+) was detectable in nodules under normal or stressed conditions, we monitored the status of Lb in intact nodules attached to sweet clover (Melilotus officinalis) and soybean (Glycine max [L.] Merr.) roots exposed to various conditions. The effects of N2 and O2 streams and elevated nicotinate levels on root-attached nodules were tested to determine whether the spectrophotometric technique was showing the predicted responses of Lb. The soybean and sweet clover nodules' Lb spectra indicated predominantly ferrous Lb and LbO2 in young (34 d) plants. As the nodule aged beyond 45 d, it was possible to induce Lb3+ with a 100% O2 stream (15 min). At 65 d without inducement, the nodule Lb status indicated the presence of some Lb3+ along with ferrous Lb and oxyferrous Lb. Nicotinate and fluoride were used as ligands to identify Lb3+. Computer-calculated difference spectra were used to demonstrate the changes in Lb spectra under different conditions. Some conditions that increased absorbance in the 626 nm region (indicating Lb3+ accumulation) were root-fed ascorbate and dehydroascorbate, plant exposure to darkness, and nodule water immersion. PMID:12228593

Lee, Kk.; Shearman, L. L.; Erickson, B. K.; Klucas, R. V.

1995-01-01

252

Localized corrosion of candidate container materials in ferric chloride solutions  

SciTech Connect

Localized corrosion behavior of candidate inner and outer container materials of currently-designed nuclear waste package was evaluated in aqueous solutions of various concentrations of ferric chloride (FeCl{sub 3}) at 30 C, 60 C and 90 C using the electrochemical cyclic potentiodynamic polarization (CPP) technique. Materials tested include A 5 16 carbon steel and high-performance alloys 825, G-3, G-30, C-4, 625. C-22, and Ti Gr-12. A 516 steel suffered from severe general and localized attack including pitting and crevice corrosion. High-nickel alloys 825 and G-3 also became susceptible to severe pitting and crevice corrosion. The extent of localized attack was less pronounced in alloys G-30 and C-4. Alloy 625 experienced severe surface degradation including general corrosion, crevice corrosion and intergranular attack. In contrast, only a slight crevice corrosion tendency was observed with nickel-base alloy C-22 in solutions containing higher concentrations of FeCl{sub 3} at 60 C and 90 C. Ti Gr-12 was immune to localized attack in all tested environments. The test solutions showed significant amount of precipitated particles during and after testing especially at higher temperatures.

Fleming, D L; Lum, B Y; Roy, A K

1998-10-01

253

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

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

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

2014-07-16

254

Nanoscale Synthesis and Functional Assembly Center for Nanophase Materials Science and  

E-print Network

and oxygen reduction at electrode-electrolyte interface, CO2 reduction at water-oxide interface. 3. Current; 3 Invited Book Chapters Collaborators: C. Barnes (University of Tennessee-Knoxville); B. Eichhorn

Pennycook, Steve

255

Bioavailability of iron from oral ferric polymaltose in humans.  

PubMed

The bioavailability or iron from iron(III)hydroxide polymaltose complex (ferric polymaltose, Fe-PM) was studied in human volunteers with normal or depleted iron stores as well as in patients with iron deficiency anemia. From an oral iron dose of 100 mg neutron activated Fe-PM, starved subjects with depleted iron stores absorbed significantly less (p < 0.003) 59Fe (3.91 +/- 2.24%, mean +/- SD) as compared to the reference, aqueous 59Fe(II) ascorbate solution (13.8 +/- 6.19%). Using non-radiolabeled, commercial Fe-PM no postabsorptive serum iron increase was found after oral Fe-PM (100 mg Fe dosage) in a group of 7 patients with haemorrhagic or posthaemorrhagic iron deficiency anemia. In addition, almost no haemoglobin increase was observed in 9 patients during a 4-weeks treatment period when given Fe-PM (100-300 mg Fe/d) on empty stomach, whereas subsequent treatment with ferrous sulfate (100-200 mg Fe/d) was therapeutically effective (0.15-0.23 g/dl Hb-increase/d). When given 100 or 300 mg Fe/d Fe-PM together with meal, 3 out of 6 patients showed a higher iron utilization rate (3.4-11.9%/d) than given without meal (0.5-7.5%/d). In vitro incubation studies demonstrated that Fe-PM is very stable at neutral pH. A small release of iron from the high molecular weight complex was found only at low pH (< 2). However, high amounts of ionic iron were measured in the reaction tubes after incubating solutions of Fe-PM together with ascorbic acid. This finding could explain the somewhat higher bioavailability of Fe-PM when given with vitamin C containing meals.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8053973

Nielsen, P; Gabbe, E E; Fischer, R; Heinrich, H C

1994-06-01

256

Iron oxide mineralogy in late Miocene red beds from La Gloria, Spain: rock-magnetic,  

E-print Network

Iron oxide mineralogy in late Miocene red beds from La Gloria, Spain: rock-magnetic, voltammetric March 2002; accepted 20 January 2003 Abstract Free ferric oxides of a red bed series were analyzed constituents. Free Fe oxides occurred at a concentration of 0.3Ā­2.1%, i.e. in the majority of the samples below

Utrecht, Universiteit

257

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

PubMed

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

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

2014-07-22

258

Treatment of Iron Deficiency With Intravenous Ferric Carboxymaltose in General Practice: A Retrospective Database Study  

PubMed Central

Background Iron deficiency is a frequent problem in general practice. Oral supplementation may in some cases not be well tolerated or not be efficient. Intravenous ferric carboxymaltose may be an alternative for iron supplementation in general practice. The aim of the present study was to analyze the indications for and the efficacy of intravenous ferric carboxymaltose in a primary care center. Methods We retropectively analyzed electronic data from 173 patients given intravenous ferric carboxymaltose between 2011 and 2013 in primary care center with 18 GPs in Bern, Switzerland. Results Of all patients, 34% were treated intravenously due to an inappropriate increase in ferritin levels after oral therapy, 24% had side effects from oral treatment, 10% were treated intravenously due to the patients explicit wish, and in 39% of all cases, no obvious reason of intravenous instead of oral treatment could be found. Intravenous ferric carboxymaltose led to a significant increase in hemoglobin and serum ferritin levels. Side effects of intravenous treatment were found in 2% of all cases. Conclusion We conclude that treatment with intravenous ferric carboxymaltose is an efficient alternative for patients with iron deficiency in general practice, when oral products are not well tolarated or effective. As treatment with iron carboxymaltose is more expensive and potentially dangerous due to side effects, the indication should be placed with (more) care. PMID:25368700

Kuster, Martina; Meli, Damian N.

2015-01-01

259

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

PubMed Central

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

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

2014-01-01

260

Recognition of Ferric Catecholates by FepA  

PubMed Central

Escherichia coli FepA transports certain catecholate ferric siderophores, but not others, nor any noncatecholate compounds. Direct binding and competition experiments demonstrated that this selectivity originates during the adsorption stage. The synthetic tricatecholate Fe-TRENCAM bound to FepA with 50- to 100-fold-lower affinity than Fe-enterobactin (FeEnt), despite an identical metal center, and Fe-corynebactin only bound at much higher concentrations. Neither Fe-agrobactin nor ferrichrome bound at all, even at concentrations 106-fold above the Kd. Thus, FepA only adsorbs catecholate iron complexes, and it selects FeEnt among even its close homologs. We used alanine scanning mutagenesis to study the contributions of surface aromatic residues to FeEnt recognition. Although not apparent from crystallography, aromatic residues in L3, L5, L7, L8, and L10 affected FepA's interaction with FeEnt. Among 10 substitutions that eliminated aromatic residues, Kd increased as much as 20-fold (Y481A and Y638A) and Km increased as much as 400-fold (Y478), showing the importance of aromaticity around the pore entrance. Although many mutations equally reduced binding and transport, others caused greater deficiencies in the latter. Y638A and Y478A increased Km 10- and 200-fold more, respectively, than Kd. N-domain loop deletions created the same phenotype: ?60-67 (in NL1) and ?98-105 (in NL2) increased Kd 10- to 20-fold but raised Km 500- to 700-fold. W101A (in NL2) had little effect on Kd but increased Km 1,000-fold. These data suggested that the primary role of the N terminus is in ligand uptake. Fluorescence and radioisotopic experiments showed biphasic release of FeEnt from FepA. In spectroscopic determinations, koff1 was 0.03/s and koff2 was 0.003/s. However, FepAY272AF329A did not manifest the rapid dissociation phase, corroborating the role of aromatic residues in the initial binding of FeEnt. Thus, the ?-barrel loops contain the principal ligand recognition determinants, and the N-domain loops perform a role in ligand transport. PMID:15150246

Annamalai, Rajasekaran; Jin, Bo; Cao, Zhenghua; Newton, Salete M. C.; Klebba, Phillip E.

2004-01-01

261

Recognition of ferric catecholates by FepA.  

PubMed

Escherichia coli FepA transports certain catecholate ferric siderophores, but not others, nor any noncatecholate compounds. Direct binding and competition experiments demonstrated that this selectivity originates during the adsorption stage. The synthetic tricatecholate Fe-TRENCAM bound to FepA with 50- to 100-fold-lower affinity than Fe-enterobactin (FeEnt), despite an identical metal center, and Fe-corynebactin only bound at much higher concentrations. Neither Fe-agrobactin nor ferrichrome bound at all, even at concentrations 10(6)-fold above the Kd. Thus, FepA only adsorbs catecholate iron complexes, and it selects FeEnt among even its close homologs. We used alanine scanning mutagenesis to study the contributions of surface aromatic residues to FeEnt recognition. Although not apparent from crystallography, aromatic residues in L3, L5, L7, L8, and L10 affected FepA's interaction with FeEnt. Among 10 substitutions that eliminated aromatic residues, Kd increased as much as 20-fold (Y481A and Y638A) and Km increased as much as 400-fold (Y478), showing the importance of aromaticity around the pore entrance. Although many mutations equally reduced binding and transport, others caused greater deficiencies in the latter. Y638A and Y478A increased Km 10- and 200-fold more, respectively, than Kd. N-domain loop deletions created the same phenotype: Delta60-67 (in NL1) and Delta98-105 (in NL2) increased Kd 10- to 20-fold but raised Km 500- to 700-fold. W101A (in NL2) had little effect on Kd but increased Km 1,000-fold. These data suggested that the primary role of the N terminus is in ligand uptake. Fluorescence and radioisotopic experiments showed biphasic release of FeEnt from FepA. In spectroscopic determinations, k(off1) was 0.03/s and k(off2) was 0.003/s. However, FepAY272AF329A did not manifest the rapid dissociation phase, corroborating the role of aromatic residues in the initial binding of FeEnt. Thus, the beta-barrel loops contain the principal ligand recognition determinants, and the N-domain loops perform a role in ligand transport. PMID:15150246

Annamalai, Rajasekaran; Jin, Bo; Cao, Zhenghua; Newton, Salete M C; Klebba, Phillip E

2004-06-01

262

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

PubMed

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

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

263

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

PubMed Central

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

Sobolev, Dmitri; Roden, Eric E.

2001-01-01

264

Microbial acquisition of iron from ferric iron bearing minerals  

SciTech Connect

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

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

1998-12-31

265

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

PubMed

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

Roe, Kelly L; Barbeau, Katherine A

2014-11-01

266

Process for the synthesis of nanophase dispersion-strengthened aluminum alloy  

DOEpatents

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.

Barbour, John C. (Albuquerque, NM); Knapp, James Arthur (Albuquerque, NM); Follstaedt, David Martin (Albuquerque, NM); Myers, Samuel Maxwell (Albuquerque, NM)

1998-12-15

267

Iron Status and Analysis of Efficacy and Safety of Ferric Carboxymaltose Treatment in Patients with Inflammatory Bowel Disease  

Microsoft Academic Search

Background and Aims: We analyzed iron deficiency and the therapeutic response following intravenous ferric carboxymaltose in a large single-center inflammatory bowel disease (IBD) cohort. Methods: 250 IBD patients were retrospectively analyzed for iron deficiency and iron deficiency anemia. A subgroup was analyzed regarding efficacy and side effects of iron supplementation with ferric carboxymaltose. Results: In the cohort (n = 250),

Florian Beigel; Beate Löhr; Rüdiger P. Laubender; Cornelia Tillack; Fabian Schnitzler; Simone Breiteneicher; Maria Weidinger; Burkhard Göke; Julia Seiderer; Thomas Ochsenkühn; Stephan Brand

2012-01-01

268

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....

269

Crystal structure of ferric-yersiniabactin, a virulence factor of Yersinia pestis.  

PubMed

Yersiniabactin (Ybt), the siderophore produced by Yersinia pestis, has been crystallized successfully in the ferric complex form and the crystal structure has been determined. The crystals are orthorhombic with a space group of P2(1)2(1)2(1) and four distinct molecules per unit cell with cell dimensions of a=11.3271(+/-0.0003)A, b=22.3556(+/-0.0006)A, and c=39.8991(+/-0.0011)A. The crystal structure of ferric Ybt shows that the ferric ion is coordinated as a 1:1 complex by three nitrogen electron pairs and three negatively charged oxygen atoms with a distorted octahedral coordination. The molecule displays a Delta absolute configuration with chiral centers at N2, C9, C10, C12, C13, and C19 in R, R, R, R, S, S configurations, respectively. Few of the crystal structures of siderophores have been solved, and those which have been are of simple hydroxamate and catechol types such as ferrioxamine B and agrobactin. To our knowledge this is the first report of the ferric crystal structure of 5-member heterocycle siderophore. PMID:16806483

Miller, M Clarke; Parkin, Sean; Fetherston, Jacqueline D; Perry, Robert D; Demoll, Edward

2006-09-01

270

Ferric citrate transport in Escherichia coli requires outer membrane receptor protein fecA.  

PubMed Central

Mutants of Escherichia coli K-12 AB2847 and of E. coli K-12 AN92 were isolated which were unable to grow on ferric citrate as the sole iron source. Of 22 mutants, 6 lacked an outer membrane protein, designated FecA protein, which was expressed by growing cells in the presence of 1 mM citrate. Outer membranes showed an enhanced binding of radioactive iron, supplied as a citrate complex, depending on the amount of FecA protein. The FecA protein was the most resistant of the proteins involved in ferric irion iron translocation across the outer membrane (FhuA = TonA, FepA, Cir, or 83K proteins) to the action of pronase P. It is also shown that previously isolated fec mutants (G. C. Woodrow et al., J. Bacteriol. 133:1524-1526, 1978) which are cotransducible with argF all lack the FecA protein. They were termed fecA to distinguish them from the other ferric citrate transport mutants, now designated fecB, which mapped in the same gene region at 7 min but were not cotransducible with ArgF. E. coli W83-24 and Salmonella typhimurium, which are devoid of a citrate-dependent iron transport system, lacked the FecA protein. It is proposed that the FecA protein participates in the transport of ferric citrate. Images PMID:7007312

Wagegg, W; Braun, V

1981-01-01

271

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...

272

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

PubMed Central

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 rat’s 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

Nouri, Saeed; Sharif, Mohammad Reza

2014-01-01

273

Simulation study of the ferrous ferric electron transfer at a metal-aqueous electrolyte interface  

Microsoft Academic Search

We report a new simulation study of the rate of ferrous–ferric electron transfer at a metal electrolyte interface. In contrast with earlier work, new features in our study include a detailed account of the effects of the field associated with the charging of the electrode, inclusion of entropic effects in the calculated free energy barriers, and a study of the

B. B. Smith; J. W. Halley

1994-01-01

274

Treatment of rheumatoid synovitis of the knee with intraarticular injection of dysprosium 165-ferric hydroxide macroaggregates  

Microsoft Academic Search

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

Clement B. Sledge; Joseph D. Zuckerman; Michael R. Zalutsky; Robert W. Atcher; Sonya Shortkroff; David R. Lionberger; Howard A. Rose; Brian J. Hurson; Peter A. Lankenner; Ronald J. Anderson; William A. Bloomer

1986-01-01

275

Repeat radiation synovectomy with dysprosium 165-ferric hydroxide macroaggregates in rheumatoid knees unresponsive to initial injection  

Microsoft Academic Search

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

Michael Vella; Joseph D. Zuckerman; Sonya Shortkroff; Prasanna Venkatesan; Clement B. Sledge

1988-01-01

276

Water Channel of Horseradish Peroxidase Studied by the Charge-Transfer Absorption Band of Ferric Heme  

E-print Network

connects the aqueous solution to the heme site. Ferric horseradish peroxidase has an absorption band at 640, it seems likely that the CT band will be sensitive to the hydration of the protein. To study this premise, the protein was incorporated into trehalose/sucrose glasses and the hydration of the sugar glasses was varied

Sharp, Kim

277

Identification and Characterization of a Novel Extracellular Ferric Reductase from Mycobacterium paratuberculosis  

Microsoft Academic Search

A novel extracellular mycobacterial enzyme was identified in the ruminant pathogen Mycobacterium para- tuberculosis. The enzyme was capable of mobilizing iron from different sources such as ferric ammonium citrate, ferritin, and transferrin by reduction of the metal. The purified reductase had a calculated Mr of 17,000, was sensitive to proteinase K treatment, and had an isoelectric point of pH 9.

MATTHIAS HOMUTH; PETER VALENTIN-WEIGAND; M. ROHDE

1998-01-01

278

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

PubMed

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 60 ± 18% soluble Fe and 46 ± 11% sulfide were recovered on graphite granules for up-stream reuse. Peak current densities of 9.5 ± 4.2 A m(-2) and minimum power requirements of 2.4 ± 0.5 kWh kg Fe(-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

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

2014-03-15

279

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...

280

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...

281

Enterobactin protonation and iron release: structural characterization of the salicylate coordination shift in ferric enterobactin.  

PubMed

The siderophore enterobactin (Ent) is produced by many species of enteric bacteria to mediate iron uptake. This iron scavenger can be reincorporated by the bacteria as the ferric complex [Fe(III)(Ent)](3)(-) and is subsequently hydrolyzed by an esterase to facilitate intracellular iron release. Recent literature reports on altered protein recognition and binding of modified enterobactin increase the significance of understanding the structural features and solution chemistry of ferric enterobactin. The structure of the neutral protonated ferric enterobactin complex [Fe(III)(H(3)Ent)](0) has been the source of some controversy and confusion in the literature. To demonstrate the proposed change of coordination from the tris-catecholate [Fe(III)(Ent)](3)(-) to the tris-salicylate [Fe(III)(H(3)Ent)](0) upon protonation, the coordination chemistry of two new model compounds N,N',N''-tris[2-(hydroxybenzoyl)carbonyl]cyclotriseryl trilactone (SERSAM) and N,N',N''-tris[2-hydroxy,3-methoxy(benzoyl)carbonyl]cyclotriseryl trilactone (SER(3M)SAM) was examined in solution and solid state. Both SERSAM and SER(3M)SAM form tris-salicylate ferric complexes with spectroscopic and solution thermodynamic properties (with log beta(110)() values of 39 and 38 respectively) similar to those of [Fe(III)(H(3)Ent)](0). The fits of EXAFS spectra of the model ferric complexes and the two forms of ferric enterobactin provided bond distances and disorder factors in the metal coordination sphere for both coordination modes. The protonated [Fe(III)(H(3)Ent)](0) complex (d(Fe)(-)(O) = 1.98 A, sigma(2)(stat)(O) = 0.00351(10) A(2)) exhibits a shorter average Fe-O bond length but a much higher static Debye-Waller factor for the first oxygen shell than the catecholate [Fe(III)(Ent)](3)(-) complex (d(Fe)(-)(O) = 2.00 A, sigma(2)(stat)(O) = 0.00067(14) A(2)). (1)H NMR spectroscopy was used to monitor the amide bond rotation between the catecholate and salicylate geometries using the gallic complexes of enterobactin: [Ga(III)(Ent)](3)(-) and [Ga(III)(H(3)Ent)](0). The ferric salicylate complexes display quasi-reversible reduction potentials from -89 to -551 mV (relative to the normal hydrogen electrode NHE) which supports the feasibility of a low pH iron release mechanism facilitated by biological reductants. PMID:16819888

Abergel, Rebecca J; Warner, Jeffrey A; Shuh, David K; Raymond, Kenneth N

2006-07-12

282

Reactions of metal ions at surfaces of hydrous iron oxide  

USGS Publications Warehouse

Cu, Ag and Cr concentrations in natural water may be lowered by mild chemical reduction involving ferric hydroxide-ferrous ion redox processes. V and Mo solubilities may be controlled by precipitation of ferrous vanadate or molybdate. Concentrations as low as 10-8.00 or 10-9.00 M are readily attainable for all these metals in oxygen-depleted systems that are relatively rich in Fe. Deposition of manganese oxides such as Mn3O4 can be catalyzed in oxygenated water by coupling to ferrous-ferric redox reactions. Once formed, these oxides may disproportionate, giving Mn4+ oxides. This reaction produces strongly oxidizing conditions at manganese oxide surfaces. The solubility of As is significantly influenced by ferric iron only at low pH. Spinel structures such as chromite or ferrites of Cu, Ni, and Zn, are very stable and if locally developed on ferric hydroxide surfaces could bring about solubilities much below 10-9.00 M for divalent metals near neutral pH. Solubilities calculated from thermodynamic data are shown graphically and compared with observed concentrations in some natural systems. ?? 1977.

Hem, J.D.

1977-01-01

283

Goethite on Mars: A Laboratory Study of Physically and Chemically Bound Water in Ferric Oxides  

Microsoft Academic Search

A thermogravimetric analysis of the decomposition of goethite-rich samples of limonite and measurement of the equilibrium vapor pressure of the water physically bound in the sample are performed. The heats of sorption for the physically bound component are determined; an activation energy of 29 4- 3 kcal\\/mole for goethite decomposition to hematite is found between 225 and 390ųC. The goethite-hematite

James B. Pollack; Douglas Pitman; Bishun N. Khare; Carl Sagan

1970-01-01

284

Chemical reactivity of microbe and mineral surfaces in hydrous ferric oxide depositing hydrothermal springs  

Microsoft Academic Search

The hot springs in Yellowstone National Park, USA, provide concentrated microbial biomass and associated mineral crusts from which surface functional group (FG) concentrations and pK a distributions can be determined. To evaluate the importance of substratum surface reactivity for solute adsorption in a natural setting, samples of iron-rich sediment were collected from three different springs; two of the springs were

S. V. LALONDE; L. AMSKOLD; T. R. MCDERMOTT; W. P. INSKEEP; K. O. KONHAUSER

2007-01-01

285

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

PubMed

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

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

2014-12-01

286

Electrical conduction studies in ferric-doped KHSO 4 single crystals  

NASA Astrophysics Data System (ADS)

Direct-current conductivity of ferric-doped (138, 267, and 490 ppm) single crystals of KHSO 4 has been studied. The mechanism for the dc conduction process is discussed. It is observed that the ferric ion forms a (Fe 3+-two vacancies) complex and the enthaply for its formation is 0.09 ± 0.01 eV. It is proposed that each ferric ion removes two protons from each HSO 4 dimer. The conductivity plot shows the presence of intrinsic and extrinsic regions. It is proposed that in the intrinsic region the dimer of HSO -4 breaks reversibly to form a long-chain monomer-type structure. The conductivity in the KHSO 4 crystal is proposed to be controlled by the rotation of HSO -4 tetrahedra along the axis which contains no hydrogen atom. Isotherm calculation for the trivalent-doped system is applied to this crystal and the results are compared with Co 2+-doped KHSO 4 crystal. The distribution coefficient of ferric ion in the KHSO 4 single crystal is calculated to be 4.5 × 10 -1. Ferric ion causes tapering in the crystal growth habit of KHSO 4 and it is believed to be due to the presence of (Fe 3+-two vacancies) complex. The enthalpy values for the various other processes are as follows: enthalpy for the breakage of HSO -4 dimer ( Hi) = 1.28 ± 0.01 eV; enthalpy for the rotation of HSO -4 tetrahedron ( Hm) = 0.58 ± 0.01 eV.

Sharon, M.; Kalia, A. K.

1980-03-01

287

Superoxide-dependent formation of hydroxyl radicals from ferric-complexes and hydrogen peroxide: an evaluation of fourteen iron chelators.  

PubMed

When a variety of ferric chelates are reacted with hydrogen peroxide in phosphate buffer deoxyribose is damaged and this damage is protected against by formate, thiourea and mannitol. Damage done by ferric complexes of citrate, EDTA, NTA, EGTA and HEDA is substantially inhibited by superoxide dismutase (SOD) whereas complexes of PLA, ADP and CDTA are moderately inhibited by SOD. The effects of SOD argue against hydrogen peroxide acting as a reductant in Fenton chemistry driven by ferric complexes and hydrogen peroxide. EDTA has proved to be a useful model for Fenton chemistry that is inhibited by SOD although, it is not unique in this respect. PMID:2161386

Gutteridge, J M

1990-01-01

288

Ferric citrate spans mineral metabolism and anemia domains in ESRD: a review of efficacy and safety data.  

PubMed

Ferric citrate (Zerenex™, Keryx Biopharmaceuticals, Inc.), a phosphate binder drug candidate, recently completed a Phase III program confirming efficacy and demonstrating safety when used to treat hyperphosphatemia in patients with end-stage renal disease. Results of these trials demonstrate that ferric citrate effectively controls serum phosphorus and is well tolerated. Additionally, these studies demonstrate that ferric citrate improves iron parameters and reduces IV iron and erythropoietin stimulating agent utilization while maintaining hemoglobin levels. These unique features may further benefit the management of end-stage renal disease-related anemia. PMID:25242077

Sinsakul, Marvin; Rodby, Roger; Umanath, Kausik; Niecestro, Robert; Dwyer, Jamie P

2014-11-01

289

Ferrous sulphate oxidation using Thiobacillus ferrooxidans cells immobilised in polyurethane foam support particles  

Microsoft Academic Search

Oxidation of ferrous iron by Thiobacillus ferrooxidans cells passively immobilised in polyurethane foam particles, using both repeated batches and continuous operation, was studied in a laboratory-scale reactor. Repeated batches yielded complete oxidation at higher rates than single batches, providing resident inocula for subsequent batches. In continuous operation maximum ferric iron productivities were achieved at dilution rates well above theoretical washout

H. Armentia; C. Webb

1992-01-01

290

Investigations of ferric heme cyanide photodissociation in myoglobin and horseradish peroxidase.  

PubMed

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

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

2013-04-18

291

Iron-Titanium Oxides and Oxygen Fugacities in Volcanic Rocks  

Microsoft Academic Search

It is shown that in silicate liquids the ferric-ferrous equilibrium is controlled by temperature, oxygen fugacity, and the composition of the liquid, particularly its alkali content. Thus, if the iron-titanium oxide minerals that precipitate from a silicate liquid reflect the ferricferrous equilibrium, the oxygen geobarometer of Buddington and Lindsley will have to be calibrated, especially for such volcanics as phonolites

I. S. E. Carmichael; J. Nicholls

1967-01-01

292

The effect of cupric and ferric ions on antioxidant properties of human serum albumi.  

PubMed

The interaction of both ferric (Fe³?) and cupric (Cu²?) ions with human serum albumin (HSA) was assayed at a temperature of 27°C in aqueous solution using isothermal titration calorimetry. The association equilibrium constant and the molar enthalpy for one binding is 1.7 × 10? M-1 and -31.37 kJ • M?¹, respectively. To obtain the binding parameters of metal ion-protein interaction over the whole range of Fe³? concentrations, the extended solvation model was applied. The solvation parameters obtained from this model were attributed to the structural change of HSA. The binding parameters obtained from the extended solvation model indicate that the stability of HSA was decreased as a result of its binding with ferric ions, which cause dampening the antioxidant property of HSA. Cuperic ion increases the stability of HSA considerably, indicating that the antioxidant property of human serum albumin are increased as a result of its interaction with cupric ion. PMID:25146186

Rezaei Behbehani, Gholamreza; Gonbadi, Katayon; Eslami, Nasrin

2014-10-01

293

Using Crystal Structure Groups to Understand Mössbauer parameters of Ferric Sulfates  

NASA Astrophysics Data System (ADS)

A Mössbauer 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 Mössbauer 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 Mössbauer 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. Mössbauer 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 Mössbauer 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 Mössbauer 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, römerite, 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 Mössbauer 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.

Knutson, J.; Dyar, M. D.; Sklute, E. C.; Lane, M. D.; Bishop, J. L.

2008-12-01

294

Enzyme-mimic activity of ferric nano-core residing in ferritin and its biosensing applications.  

PubMed

Ferritins are nanoscale 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 nanocore 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 nanobiosensors, thus holds promising potential for facile and biocompatible labeling for sensitive and robust bioassays in biomedical applications. PMID:21910434

Tang, Zhiwen; Wu, Hong; Zhang, Youyu; Li, Zhaohui; Lin, Yuehe

2011-11-15

295

Identification, cloning, and sequencing of a gene required for ferric vibriobactin utilization by Vibrio cholerae.  

PubMed Central

Chromosomal DNA downstream of the Vibrio cholerae ferric vibriobactin receptor gene, viuA, was cloned and sequenced, revealing an 813-bp open reading frame encoding a deduced protein of 271 amino acids. In vitro transcription-translation of this DNA confirmed expression of a protein of the expected size. A deletion mutation of this gene, viuB, was created in the classical V. cholerae strain O395 by in vivo marker exchange. By cross-feeding studies, this mutant was unable to utilize exogenous ferric vibriobactin but synthesized the siderophore normally; synthesis of siderophore by the mutant was also confirmed by the Arnow assay. Complementation of the mutant with a plasmid encoding only viuB restored ferric vibriobactin utilization to normal. Unexpectedly, hydropathicity analysis of ViuB did not reveal a signal sequence or transmembrane domain, suggesting that ViuB is not a periplasmic or membrane protein but may be a cytoplasmic protein involved in ferric vibriobactin uptake and processing, perhaps analogous to the Escherichia coli protein Fes. ViuB was not, however, homologous to Fes or to other proteins in the database. Complementation studies revealed that the cloned V. cholerae viuB gene could complement an E. coli fes mutant but that the cloned E. coli fes gene could not complement a V. cholerae viuB mutant. Northern (RNA) blot analysis of RNA from wild-type V. cholerae grown in high- and low-iron media revealed a monocistronic viuB message that was negatively regulated by iron at the transcriptional level. The promoter of viuB was located by primer extension and contained a nucleotide sequence highly homologous to the E. coli Fur binding consensus sequence, suggesting that expression of viuB is under the control of the V. cholerae fur gene. Images PMID:8083157

Butterton, J R; Calderwood, S B

1994-01-01

296

Microscale speciation of arsenic and iron in ferric-based sorbents subjected to simulated landfill conditions  

PubMed Central

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, 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. 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

Root, Robert A.; Fathordoobadi, Sahar; Alday, Fernando; Ela, Wendell; Chorover, Jon

2013-01-01

297

Repeat radiation synovectomy with dysprosium 165-ferric hydroxide macroaggregates in rheumatoid knees unresponsive to initial injection  

SciTech Connect

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.

Vella, M.; Zuckerman, J.D.; Shortkroff, S.; Venkatesan, P.; Sledge, C.B.

1988-06-01

298

Treatment of antigen-induced arthritis in rabbits with dysprosium-165-ferric hydroxide macroaggregates  

Microsoft Academic Search

Dysprosium-165-ferric hydroxide macroaggregates (Ā¹ā¶āµDy-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. Ā¹ā¶āµDy-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

Joseph D. Zuckerman; Clement B. Sledge; Sonya Shortkroff; Prasanna Venkatesan

1989-01-01

299

Equivalent bioavailability of iron from ferrous salts and a ferric polymaltose complex. Clinical and experimental studies.  

PubMed

In both experimental animals and human subjects iron absorption over a wide dosage range was quantitatively equivalent from ferrous salts and a ferric polymaltose complex under basal conditions. The comparable bioavailability was maintained when demand was increased by iron depletion or erythroid stimulation and depressed by expansion of body stores or impaired erythropoiesis. This common pattern for iron retention from both salt and complex supports the interchangeable use of these products in therapy of absolute iron deficiency. PMID:3566865

Jacobs, P

1987-01-01

300

Capillary electrophoretic determination of ferric dimethyldithiocarbamate as iron(III) chelate of EDTA  

Microsoft Academic Search

A simple and sensitive capillary electrophoretic method with UV detection has been developed for the determination of Ferbam (ferric dimethyldithiocarbamate) in boric acid buffer after its acidic decomposition and complexation with EDTA as Fe–EDTA? complex. The determination is dependent on the pH and the nature of the buffer solutions. In this method the detection limit (S\\/N=3) is 1.8·10?6 mol\\/L (0.7

Ashok Kumar Malik; Bernd Stefan Seidel; Werner Faubel

1999-01-01

301

Physicochemical Characterization of Granular Ferric Hydroxide (GFH) for Arsenic(V) Sorption from Water  

Microsoft Academic Search

Physical and chemical characterization of granular ferric hydroxide (GFH) [e.g., scanning electron micrographs (SEM), X?ray diffraction (XRD) analysis, Brunauer?Emmett?Teller (BET) and Langmuir surface area measurements, pore size distribution, pH titration, and zeta potential measurements] were conducted to determine its performance as an adsorbent for trace arsenic(V) removal. Speciation diagrams for arsenate and phosphate were produced for the present system. The

B. Saha; R. Bains; F. Greenwood

2005-01-01

302

The effects of pH regulation upon the release of sulfate from ferric precipitates formed in acid mine drainage  

Microsoft Academic Search

`Batch experiments' (25:1 v:w) were used to test the effects of pH upon the release of SO?24 from ferric precipitates formed in acid mine drainage (AMD) in southeastern Kentucky. Analytical grade CaO [`quicklime'], Ca(OH)2 [hydrated lime] and CaCO3 [referred to as `limestone'] were used as alkalinity generating agents and were mixed with ferric precipitates composed of amorphous iron oxyhydroxides, jarosite

Seth Rose; W. Crawford Elliott

2000-01-01

303

Point defects in (Mg,Fe)O at high pressures: where does hydrogen dominate over ferric iron?  

Microsoft Academic Search

The point defects play an important role in transport processes of minerals including diffusion, electrical conduction and plastic deformation. Point defects caused by ferric iron and\\/or hydrogen (proton) are dominant defects in most of the iron-bearing minerals including olivine and (Mg,Fe)O. In many upper-mantle minerals such as olivine, the concentration of ferric iron is much smaller than that of hydrogen,

K. Otsuka; S. Karato

2007-01-01

304

Ferric chelate reduction by sunflower ( Helianthus annuus L.) leaves: influence of light, oxygen, iron-deficiency and leaf age  

Microsoft Academic Search

The presence of ferric chelate reducing activity in sunflower (Helianthus annuus L.) leaves has been studied by submerging leaf discs in a solution with Fe(lll)-ethylenediaminetetra-acetate (FeEDTA), batho- phenanthroline disulphonate (BPDS) and vacuum infil- tration. The effect of different factors on the Fe(lll) reduction rate was studied. Ferric reduction rate was about 10-fold higher in the light than in darkness. The

Manuel D. de la Guardia; Esteban Alc“ntara

1996-01-01

305

Inhibition of sulfate-reducing and methanogenic activities of anaerobic sewer biofilms by ferric iron dosing.  

PubMed

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

Zhang, Lishan; Keller, Jürg; Yuan, Zhiguo

2009-09-01

306

Reduced adsorption of ametryn in clay, humic acid, and soil by interaction with ferric ion under Fenton treatment conditions.  

PubMed

Previous work in our laboratory indicated a weak interaction between ferric ion and several triazine/triazinone herbicides during a Fenton treatment process, and the intensity of the interaction was calculated. To further support the existence of this weak interaction, the adsorption of ametryn, a triazine herbicide, was investigated in kaolinite clay, humic acid, and soil under pseudo-Fenton conditions. At a low addition rate of ferric ion, the adsorption of ametryn in clay, humic acid, and soil was enhanced due to the decreased pH resulting from the hydrolysis of ferric ion. But the pH effect was totally neutralized and the adsorption of ametryn was significantly reduced by further addition of ferric ion, demonstrating the existence of the weak interaction between ametryn and ferric acid. Further study showed that the adsorption-reduction effect of ferric ion existed not only with ametryn but also with several other triazine/triazinone herbicides. This weak interaction may accelerate the desorption process during the remediation of triazine/triazinone herbicide-contaminated soil using a Fenton/Fenton-like treatment, but it may also impede the degradation of these herbicides. PMID:16484083

Wang, Qiquan; Lemley, Ann T

2006-01-01

307

Polybenzimidazole block copolymers for fuel cell: synthesis and studies of block length effects on nanophase separation, mechanical properties, and proton conductivity of PEM.  

PubMed

A series of meta-polybenzimidazole-block-para-polybenzimidazole (m-PBI-b-p-PBI), segmented block copolymers of PBI, were synthesized with various structural motifs and block lengths by condensing the diamine terminated meta-PBI (m-PBI-Am) and acid terminated para-PBI (p-PBI-Ac) oligomers. NMR studies and existence of two distinct glass transition temperatures (Tg), obtained from dynamical mechanical analysis (DMA) results, unequivocally confirmed the formation of block copolymer structure through the current polymerization methodology. Appropriate and careful selection of oligomers chain length enabled us to tailor the block length of block copolymers and also to make varieties of structural motifs. Increasingly distinct Tg peaks with higher block length of segmented block structure attributed the decrease in phase mixing between the meta-PBI and para-PBI blocks, which in turn resulted into nanophase segregated domains. The proton conductivities of proton exchange membrane (PEM) developed from phosphoric acid (PA) doped block copolymer membranes were found to be increasing substantially with increasing block length of copolymers even though PA loading of these membranes did not alter appreciably with varying block length. For example when molecular weight (Mn) of blocks were increased from 1000 to 5500 then the proton conductivities at 160 °C of resulting copolymers increased from 0.05 to 0.11 S/cm. Higher block length induced nanophase separation between the blocks by creating less morphological barrier within the block which facilitated the movement of the proton in the block and hence resulting higher proton conductivity of the PEM. The structural varieties also influenced the phase separation and proton conductivity. In comparison to meta-para random copolymers reported earlier, the current meta-para segmented block copolymers were found to be more suitable for PBI-based PEM. PMID:24712484

Maity, Sudhangshu; Jana, Tushar

2014-05-14

308

Ferric Iron Precipitation in the Nagahama Bay, Satsuma Iwo-Jima Island, Kagoshima  

NASA Astrophysics Data System (ADS)

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.

Nagata, T.; Kiyokawa, S.; Ikehara, M.; Oguri, K.; Goto, S.; Ito, T.; Yamaguchi, K. E.; Ueshiba, T.

2010-12-01

309

Photoreductive dissolution of colloidal iron oxides in natural waters  

Microsoft Academic Search

Size-separation (0.1-pm filtration and ultrafiltration) techniques and coulometric procedures have been used to investigate the photoreductive dissolution of iron oxides under conditions typical of natural waters. In the absence of organic agents, iron oxides are solubilized to varying degrees through photodissociation of ferric hydroxy groups at the colloid surface. The degree of dissolution is de- pendent principally on the chromophore

T. David Waite; Francois M. M. Morel

1984-01-01

310

Asoxime (HI6) impact on dogs after one and tenfold therapeutic doses: Assessment of adverse effects, distribution, and oxidative stress  

Microsoft Academic Search

Asoxime (HI-6) is a well known oxime reactivator used for counteracting intoxication by nerve agents. It is able to reactivate acetylcholinesterase (AChE) inhibited even by sarin or soman. The present experiment was aimed to determine markers of oxidative stress represented by thiobarbituric acid reactive substances and antioxidants represented by ferric reducing antioxidant power, reduced and oxidized glutathione in a Beagle

Miroslav Pohanka; Ladislav Novotny; Jana Zdarova-Karasova; Hana Bandouchova; Filip Zemek; Martina Hrabinova; Jan Misik; Kamil Kuca; Jiri Bajgar; Ondrej Zitka; Natalia Cernei; Rene Kizek; Jiri Pikula

2011-01-01

311

Cost-utility of ferric carboxymaltose (Ferinject®) for iron-deficiency anemia patients with chronic heart failure in South Korea  

PubMed Central

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 24 weeks. 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

2014-01-01

312

Continuous biological ferrous iron oxidation in a submerged membrane bioreactor.  

PubMed

Microbial oxidation of ferrous iron may be available alternative method of producing ferric iron, which is a reagent used for removal of H2S from biogas. In this study, a submerged membrane bioreactor (MBR) system was employed to oxidize ferrous iron to ferric iron. In the submerged MBR system, we could keep high concentration of iron-oxidizing bacteria and high oxidation rate of ferrous iron. There was membrane fouling caused by chemical precipitates such as K-jarosite and ferric phosphate. However, a strong acidity (pH 1.75) of solution and low ferrous iron concentration (below 3000 mg/I) significantly reduced the fouling of membrane module during the bioreactor operation. A fouled membrane module could be easily regenerated with a 1 M of sulfuric acid solution. In conclusion, the submerged MBR could be used for high-density culture of iron-oxidizing bacteria and for continuous ferrous iron oxidation. As far as our knowledge concerns, this is the first study on the application of a submerged MBR to high acidic conditions (below pH 2). PMID:16003962

Park, D; Lee, D S; Park, J M

2005-01-01

313

Extended X-ray Absorption Fine Structure (EXAFS) in Stardust tracks: Constraining the origin of ferric iron-bearing minerals  

NASA Astrophysics Data System (ADS)

X-ray Absorption Fine Structure techniques have been used on Comet Wild2/81P tracks from the Stardust mission. Fe-XANES and EXAFS have been performed on aerogel sections from Tracks 41 and 162 as well as the mid and terminal positions of Track 134. This is the first use of EXAFS in the study of early Solar System materials. With EXAFS, we have measured Fe-O and Fe-S bond lengths and thus, together with complementary XANES measurements, identified Fe-rich phases. In particular, we show that ferric-rich phases in 2 Tracks (41, 162) have Fe-O bond 1st shell bond lengths of 1.99-2.01 Å and Fe K absorption edge and pre edge centroid positions consistent with being hematite-dominated grains. These iron oxides can be clearly distinguished from a magnetite grain, present in Track 134. We also demonstrate the identification of the Mg-rich end member olivine using EXAFS with XANES in Track 162. The terminal grain of Track 134 is pyrrhotite, its first atomic shell has an Fe-S structure, with 4 nearest neighbouring S atoms at a distance of 2.29 ± 0.05 Å. Our XANES results show the presence of Fe3+-bearing grains along the Stardust tracks and suggest either flash-cooling of an Fe-S-SiO-O2 gas during capture or the presence of a Fe-Ni-S-O melt along the cometary tracks during impact capture in the aerogel, rather than the capture process being solely associated with reduction of cometary phases. Accurate determination of Comet Wild2 redox conditions requires the identification of phases, in particular terminal grains, which have not experienced this melting. For instance, the larger hematite-rich grains (>10 ?m) are more likely to be cometary in origin. EXAFS provides a valuable new analytical technique to study fine-grained early Solar System materials.

Changela, Hitesh G.; Bridges, John C.; Gurman, Steven J.

2012-12-01

314

Resonant Inelastic X-ray Scattering on Ferrous and Ferric Bis-imidazole Porphyrin and Cytochrome c: Nature and Role of the Axial Methionine-Fe Bond.  

PubMed

Axial Cu-S(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 Fe-S(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

Kroll, Thomas; Hadt, Ryan G; Wilson, Samuel A; Lundberg, Marcus; Yan, James J; Weng, Tsu-Chien; Sokaras, Dimosthenis; Alonso-Mori, Roberto; Casa, Diego; Upton, Mary H; Hedman, Britt; Hodgson, Keith O; Solomon, Edward I

2014-12-31

315

Ferric Iron Reduction by Bacteria Associated with the Roots of Freshwater and Marine Macrophytes†  

PubMed Central

In vitro assays of washed, excised roots revealed maximum potential ferric iron reduction rates of >100 ?mol g (dry weight)?1 day?1 for three freshwater macrophytes and rates between 15 and 83 ?mol (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°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

King, G. M.; Garey, Meredith A.

1999-01-01

316

Car–Parrinello molecular dynamics in the DFT + U formalism: Structure and energetics of solvated ferrous and ferric ions  

SciTech Connect

The research described in this product was performed in part in the Environmental Molecular Sciences Laboratory, a national scientific user facility sponsored by the Department of Energy's Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory. We implemented a rotationally-invariant Hubbard U extension to density-functional theory in the Car–Parrinello molecular dynamics framework, with the goal of bringing the accuracy of the DFT + U approach to finite-temperature simulations, especially for liquids or solids containing transition-metal ions. First, we studied the effects on the Hubbard U on the static equilibrium structure of the hexaaqua ferrous and ferric ions, and the inner-sphere reorganization energy for the electron-transfer reaction between aqueous ferrous and ferric ions. It is found that the reorganization energy is increased, mostly as a result of the Fe–O distance elongation in the hexa-aqua ferrous ion. Second, we performed a first-principles molecular dynamics study of the solvation structure of the two aqueous ferrous and ferric ions. The Hubbard term is found to change the Fe–O radial distribution function for the ferrous ion, while having a negligible effect on the aqueous ferric ion. Moreover, the frequencies of vibrations between Fe and oxygen atoms in the first-solvation shell are shown to be unaffected by the Hubbard corrections for both ferrous and ferric ions.

Sit, P H L.; Cococcioni, Matteo; Marzari, Nicola N.

2007-09-01

317

Ferric chloride-graphite intercalation compounds as anode materials for Li-ion batteries.  

PubMed

Ferric chloride-graphite intercalation compounds (FeCl3 -GICs) with stage 1 and stage 2 structures were synthesized by reacting FeCl3 and expanded graphite (EG) in air in a stainless-steel autoclave. As rechargeable Li-ion batteries, these FeCl3 -GICs exhibit high capacity, excellent cycling stability, and superior rate capability, which could be attributed to their unique intercalation features. This work may enable new possibilities for the fabrication of Li-ion batteries. PMID:24339264

Wang, Lili; Zhu, Yongchun; Guo, Cong; Zhu, Xiaobo; Liang, Jianwen; Qian, Yitai

2014-01-01

318

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

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.

Mashapa, T.N.; Rademan, J.D.; van Vuuren, M.J.J. [Sasol Technology Research & Development, Sasolburg (South Africa)

2007-09-15

319

Ferric Carboxymaltose  

PubMed Central

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 January 2014 monograph topics are obinutuzumab, anti-inhibitor coagulant complex, macitentan, riociguat, and conjugated estrogens/bazedoxifene. The DUE/MUE is on conjugated estrogens/bazedoxifene. PMID:24421564

Cada, Dennis J.; Levien, Terri L.; Baker, Danial E.

2014-01-01

320

Ferric carboxymaltose.  

PubMed

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 January 2014 monograph topics are obinutuzumab, anti-inhibitor coagulant complex, macitentan, riociguat, and conjugated estrogens/bazedoxifene. The DUE/MUE is on conjugated estrogens/bazedoxifene. PMID:24421564

Cada, Dennis J; Levien, Terri L; Baker, Danial E

2014-01-01

321

Chlorinated aromatic compounds in a thermal process promoted by oxychlorination of ferric chloride.  

PubMed

The relationship between the formation of chlorinated aromatic (aromatic-Cl) compounds and ferric chloride in the solid phase during a thermal process motivated us to study the chemical characteristics of iron in a model solid sample, a mixture of FeCl(3) x 6H(2)O, activated carbon, and boron nitride, with increasing temperature. Fe K-edge extended X-ray absorption fine structure (EXAFS) spectroscopy revealed drastic changes in the chemical form of amorphous iron, consistent with other analytical methods, such as X-ray diffraction using synchrotron radiation (SR-XRD) and Fourier-transform infrared (FT-IR) spectroscopy. Atomic-scale evidence of the chlorination of aromatic carbon was detected by Cl-K X-ray absorption near edge structure (XANES) spectroscopy. These results showed the thermal formation mechanism of aromatic-Cl compounds in the solid phase with ferric chloride. We attribute the formation of aromatic-Cl compounds to the chlorination of carbon, based on the oxychlorination reaction of FeCl(3) at temperatures in excess of ca. 300 degrees C, when the carbon matrix is activated by carbon gasification, catalyzed by Fe(2)O(3), and surface oxygen complexes (SOC) generated by a catalytic cycle of FeCl(2) and FeOCl. Chemical changes of trace iron in a thermal process may offer the potential to generate aromatic-Cl compounds in the solid phase. PMID:20170161

Fujimori, Takashi; Takaoka, Masaki; Morisawa, Shinsuke

2010-03-15

322

Gene cluster for ferric iron uptake in Agrobacterium tumefaciens MAFF301001.  

PubMed

Agrobacterium tumefaciens harboring a Ti plasmid causes crown gall disease in dicot plants by transferring its T-DNA into plant chromosomes. Iron acquisition plays an important role for pathogenicity in animal pathogens and several phytopathogens and for growth in the rhizosphere and on plant surfaces. Under iron-limiting condition, bacteria produce various iron-chelating agents called siderophores. Agrobacterium strains have the diversity in producing siderophores and a certain strain produces a typical catechol-type siderophore, called agrobactin, although its biosynthesis genes have not been analyzed yet. Here we describe the cloning and characterization of a functional gene cluster involved in ferric iron uptake in A. tumefaciens strain MAFF301001. Four complete open reading frames (ORFs) were found in 5-kb region of a genomic library clone 1A3. We named these genes agb, after agrobactin. agbC, agbE, agbB and agbA genes were identified in this order, and narrow intergenic spaces suggested that these genes constitute an operon. Predicted agb gene products and their phylogenetic analysis showed sequence similarity with enzymes which are involved in ferric iron uptake in other bacteria. Southern hybridization analysis clearly indicated the location of agb genes on the linear chromosome in strain MAFF301001 but the complete lack in another A. tumefaciens strain C58. Mutation analysis of agbB revealed that it is essential for growth and production of catechol compounds in iron-limiting medium. PMID:12207035

Sonoda, Hiroyuki; Suzuki, Katsunori; Yoshida, Kazuo

2002-06-01

323

Ferric Citrate Hydrate as a Phosphate Binder and Risk of Aluminum Toxicity  

PubMed Central

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

Gupta, Ajay

2014-01-01

324

Iron sucrose and ferric carboxymaltose: no correlation between physicochemical stability and biological activity.  

PubMed

Intravenous iron preparations, like iron sucrose (IS) and ferric carboxymaltose (FCM) differ in their physicochemical stability. Thus differences in storage and utilization can be expected and were investigated in a non-clinical study in liver parenchyma HepG2-cells and THP-1 macrophages as models for toxicological and pharmacological target cells. HepG2-cells incorporated significant amounts of IS, elevated the labile iron pool (LIP) and ferritin and stimulated iron release. HepG2-cells had lower basal cellular iron and ferritin content than THP-1 macrophages, which showed only marginal accumulation of IS and FCM. However, FCM increased the LIP up to twofold and significantly elevated ferritin within 24 h in HepG2-cells. IS and FCM were non-toxic for HepG2-cells and THP-1 macrophages were more sensitive to FCM compared to IS at all concentrations tested. In a cell-free environment redox-active iron was higher with IS than FCM. Biostability testing via assessment of direct transfer to serum transferrin did not reflect the chemical stability of the complexes (i.e., FCM > IS). Effect of vitamin C on mobilisation to transferrin was an increase with IS and interestingly a decrease with FCM. In conclusion, FCM has low bioavailability for liver parenchyma cells, therefore liver iron deposition is unlikely. Ascorbic acid reduces transferrin-chelatable iron from ferric carboxymaltose, thus effects on hepcidin expression should be investigated in clinical studies. PMID:25326244

Praschberger, Monika; Haider, Kathrin; Cornelius, Carolin; Schitegg, Markus; Sturm, Brigitte; Goldenberg, Hans; Scheiber-Mojdehkar, Barbara

2015-02-01

325

In situ structural characterization of ferric iron dimers in aqueous solutions: identification of ?-oxo species.  

PubMed

The structure of ferric iron (Fe(3+)) dimers in aqueous solutions has long been debated. In this work, we have determined the dimer structure in situ in aqueous solutions using extended X-ray absorption fine structure (EXAFS) spectroscopy. An Fe K-edge EXAFS analysis of 0.2 M ferric nitrate solutions at pH 1.28-1.81 identified a Fe-Fe distance at ?3.6 Å, strongly indicating that the dimers take the ?-oxo form. The EXAFS analysis also indicates two short Fe-O bonds at ?1.80 Å and ten long Fe-O bonds at ?2.08 Å, consistent with the ?-oxo dimer structure. The scattering from the Fe-Fe paths interferes destructively with that from paths belonging to Fe(OH2)6(3+) monomers that coexist with the dimers, leading to a less apparent Fe shell in the EXAFS Fourier transform. This might be a reason why the characteristic Fe-Fe distance was not detected in previous EXAFS studies. The existence of ?-oxo dimers is further confirmed by Mössbauer analyses of analogous quick frozen solutions. This work also explores the electronic structure and the relative stability of the ?-oxo dimer in a comparison to the dihydroxo dimer using density function theory (DFT) calculations. The identification of such dimers in aqueous solutions has important implications for iron (bio)inorganic chemistry and geochemistry, such as understanding the formation mechanisms of Fe oxyhydroxides at molecular scale. PMID:23701439

Zhu, Mengqiang; Puls, Brendan W; Frandsen, Cathrine; Kubicki, James D; Zhang, Hengzhong; Waychunas, Glenn A

2013-06-17

326

Iron pharmacokinetics after administration of ferric-hydroxide-polymaltose complex in rats.  

PubMed

This paper reports a study of the pharmacokinetics of ferrous sulphate and ferric-hydroxide-polymaltose complex (Hw 6400, Ferrum Hausmann) administered orally and intravenously to anaemic and non-anaemic rats of both sexes. Radiolabelled ferrous sulphate and ferric-hydroxide-polymaltose complex was used to study iron utilization after oral administration. Measurements of radioactivity in serum, packed red cells, whole blood, liver, kidney, spleen, bone and in some cases in the gastrointestinal tract were made following a range of dosages between 0.84 and 41.9 mg Fe/kg. No significant difference in bioavailability or iron utilization was found between the two iron preparations. Pharmacokinetic measurements following i.v. administration showed different distribution volumes, iron clearance and elimination constants for the two preparations. This difference in pharmacokinetic behaviour following oral administration, particularly in the case of non-anaemic rats, was confirmed by the observation that a 10- to 20 fold smaller dose of FeSO4 than of iron-polymaltose complex was required to achieve the same rise in serum iron. It is therefore not justifiable to draw conclusions about the bioavailability of chemically different iron preparations (iron salts and iron hydroxide complexes) on the basis of AUC values for serum iron increases observed in non-anaemic animals or human subjects. PMID:6543131

Geisser, P; Müller, A

1984-01-01

327

Human exposure to ferric sulfate aerosol: effects on pulmonary function and respiratory symptoms  

SciTech Connect

Twenty normal and 18 asthmatic human volunteers were exposed to ferric sulfate aerosol at a nominal concentration of 75 ..mu..g/m/sup 3/ (equivalent to 20 ..mu..g iron/m/sup 3/). The concentration and particle size distribution were selected to simulate worst case ambient conditions. A double-blind protocol was followed in which each subject was exposed on two days, separated by about a three week period. The subjects were exposed to clean air (sham) on one day and to ferric sulfate aerosol on the other (exposure); the order of exposure was selected randomly. Pulmonary function tests were performed immediately before (pre) and after (post) each 2 h sham or exposure period; this protocol included intermittent excercise. On the average, the two groups of subjects did not exhibit significant pre- to post-changes in total respiratory system resistance, forced expiratory flow/volume performance, and single breath nitrogen washout parameters. None of the subjects reported more than slight changes in symptoms during exposure.

Kleinman, M.T.; Linn, W.S.; Bailey,, R.M.; Anderson, K.R.; Whynot, J.D.; Medway, D.A.; Hackney, J.D.

1981-04-01

328

Red blood cells mediate the onset of thrombosis in the ferric chloride murine model  

PubMed Central

Application of ferric chloride (FeCl3) to exposed blood vessels is widely used to initiate thrombosis in laboratory mice. Because the mechanisms by which FeCl3 induces endothelial injury and subsequent thrombus formation are little understood, we used scanning electron and brightfield intravital microscopy to visualize endothelial damage and thrombus formation occurring in situ. Contrary to generally accepted belief, FeCl3 does not result in appreciable subendothelial exposure within the time frame of thrombosis. Furthermore, the first cells to adhere to FeCl3-treated endothelial surfaces are red blood cells (RBCs) rather than platelets. Energy dispersive x-ray spectroscopy demonstrated that ferric ions predominantly localize to endothelial-associated RBCs and RBC-derived structures rather than to the endothelium. With continuing time points, RBC-derived structures rapidly recruit platelets, resulting in large complexes that subsequently enlarge and coalesce, quickly covering the endothelial surface. Further studies demonstrated that neither von Willebrand factor nor platelet glycoprotein Ib-? receptor (GPIb-?) is required for RBCs to adhere to the endothelium, and that deficiency of GPIb-? greatly abrogated the recruitment of platelets to the endothelial-associated RBC material. These findings illuminate the mechanisms of FeCl3-mediated thrombosis and reveal a previously unrecognized ability of RBCs to participate in thrombosis by mediating platelet adhesion to the intact endothelial surface. PMID:23343833

Barr, Justin D.; Chauhan, Anil K.; Schaeffer, Gilbert V.; Hansen, Jessica K.

2013-01-01

329

Identification and Characterization of a Novel-type Ferric Siderophore Reductase from a Gram-positive Extremophile*  

PubMed Central

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 Ki values in the micromolar range. The principal catalytic mechanism was found to couple increasing Km and KD values of substrate binding with increasing kcat 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 ?fchR 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

Miethke, Marcus; Pierik, Antonio J.; Peuckert, Florian; Seubert, Andreas; Marahiel, Mohamed A.

2011-01-01

330

Identification and characterization of a novel-type ferric siderophore reductase from a gram-positive extremophile.  

PubMed

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 ?fchR 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

Miethke, Marcus; Pierik, Antonio J; Peuckert, Florian; Seubert, Andreas; Marahiel, Mohamed A

2011-01-21

331

Shallow-water hydrothermal system and sedimentation of the ferric deposit in the Nagahama-bay, Satsuma Iwo-jima Island  

NASA Astrophysics Data System (ADS)

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.

Ninomiya, T.; Kiyokawa, S.; Koge, S.; Oguri, K.; Yamaguchi, K. E.; Ito, T.; Ikehara, M.

2008-12-01

332

The siderophore-interacting protein YqjH acts as a ferric reductase in different iron assimilation pathways of Escherichia coli.  

PubMed

Siderophore-interacting proteins (SIPs), such as YqjH from Escherichia coli, are widespread among bacteria and commonly associated with iron-dependent induction and siderophore utilization. In this study, we show by detailed biochemical and genetic analyses the reaction mechanism by which the YqjH protein is able to catalyze the release of iron from a variety of iron chelators, including ferric triscatecholates and ferric dicitrate, displaying the highest efficiency for the hydrolyzed ferric enterobactin complex ferric (2,3-dihydroxybenzoylserine)(3). Site-directed mutagenesis revealed that residues K55 and R130 of YqjH are crucial for both substrate binding and reductase activity. The NADPH-dependent iron reduction was found to proceed via single-electron transfer in a double-displacement-type reaction through formation of a transient flavosemiquinone. The capacity to reduce substrates with extremely negative redox potentials, though at low catalytic rates, was studied by displacing the native FAD cofactor with 5-deaza-5-carba-FAD, which is restricted to a two-electron transfer. In the presence of the reconstituted noncatalytic protein, the ferric enterobactin midpoint potential increased remarkably and partially overlapped with the effective E(1) redox range. Concurrently, the observed molar ratios of generated Fe(II) versus NADPH were found to be ~1.5-fold higher for hydrolyzed ferric triscatecholates and ferric dicitrate than for ferric enterobactin. Further, combination of a chromosomal yqjH deletion with entC single- and entC fes double-deletion backgrounds showed the impact of yqjH on growth during supplementation with ferric siderophore substrates. Thus, YqjH enhances siderophore utilization in different iron acquisition pathways, including assimilation of low-potential ferric substrates that are not reduced by common cellular cofactors. PMID:22098718

Miethke, Marcus; Hou, Jie; Marahiel, Mohamed A

2011-12-20

333

Enargite oxidation: A review  

NASA Astrophysics Data System (ADS)

Enargite, Cu 3AsS 4, is common in some deposit types, e.g. porphyry systems and high sulphidation epithermal deposits. It is of environmental concern as a potential source of arsenic. In this communication, we review the current knowledge of enargite oxidation, based on the existing literature and our own original data. Explicit descriptions of enargite oxidation in natural environments are scarce. The most common oxidized alteration mineral of enargite is probably scorodite, FeAsO 4.2H 2O, with iron provided most likely by pyrite, a phase almost ubiquitously associated with enargite. Other secondary minerals after enargite include arsenates such as chenevixite, Cu 2Fe 2(AsO 4) 2(OH) 4.H 2O, and ceruleite, Cu 2Al 7(AsO 4) 4.11.5H 2O, and sulphates such as brochantite, Cu 4(SO 4)(OH) 6, and posnjakite, Cu 4(SO 4)(OH) 6·H 2O. Detailed studies of enargite field alteration at Furtei, Sardinia, suggest that most alteration occurs through dissolution, as testified by the appearance of etch pits at the surface of enargite crystals. However, apparent replacement by scorodite and cuprian melanterite was observed. Bulk oxidation of enargite in air is a very slow process. However, X-ray photoelectron spectroscopy (XPS) reveals subtle surface changes. From synchrotron-based XPS it was suggested that surface As atoms react very fast, presumably by forming bonds with oxygen. Conventional XPS shows the formation, on aged samples, of a nanometer-size alteration layer with an appreciably distinct composition with respect to the bulk. Mechanical activation considerably increases enargite reactivity. In laboratory experiments at acidic to neutral pH, enargite oxidation/dissolution is slow, although it is accelerated by the presence of ferric iron and/or bacteria such as Acidithiobacillus ferrooxidans and Sulfolobus BC. In the presence of sulphuric acid and ferric iron, the reaction involves dissolution of Cu and formation of native sulphur, subsequently partly oxidized to sulphate. At alkaline pH, the reactivity of enargite is apparently slightly greater. XPS spectra of surfaces conditioned at pH 11 have been interpreted as evidence of formation of a number of surface species, including cupric oxide and arsenic oxide. Treatment with hypochlorite solutions at pH 12.5 quickly produces a coating of cupric oxide. Electrochemical oxidation of enargite typically involves low current densities, confirming that the oxidation process is slow. Important surface changes occur only at high applied potentials, e.g. + 0.74 V vs. SHE. It is confirmed that, at acidic pH, the dominant process is Cu dissolution, accompanied (at + 0.56 V vs. SHE, pH = 1) by formation of native sulphur. At alkaline pH, a number of surface products have been suggested, including copper and arsenic oxides, and copper arsenates. XPS studies of the reacted surfaces demonstrate the evolution of Cu from the monovalent to the divalent state, the formation of As-O bonds, and the oxidation of sulphur to polysulphide, sulphite and eventually sulphate. In most natural and quasi-natural (mining) situations, it is expected that enargite reactivity will be slow. Moreover, it is likely that the release of arsenic will be further slowed down by at least temporary trapping in secondary phases. Therefore, an adequate management of exposed surfaces and wastes should minimize the environmental impact of enargite-bearing deposits. In spite of an increasing body of data, there are several gaps in our knowledge of enargite oxidation. The exact nature of most mechanisms and products remains poorly constrained, and there is a lack of quantitative data on the dependence on parameters such as pH and dissolved oxygen.

Lattanzi, Pierfranco; Da Pelo, Stefania; Musu, Elodia; Atzei, Davide; Elsener, Bernhard; Fantauzzi, Marzia; Rossi, Antonella

2008-01-01

334

Magneto-optical effects from nanophase ?-Fe and Fe3O4 precipitates formed in yttrium-stabilized ZrO2 by ion implantation and annealing  

NASA Astrophysics Data System (ADS)

Magneto-optically active nanocomposite structures have been created by using ion implantation and thermal processing to form precipitated layers of ferromagnetic ?-Fe or ferrimagnetic Fe3O4 that are embedded in the near-surface region of (100)-oriented yttrium stabilized ZrO2 (YSZ). When Fe-implanted YSZ is annealed at 1100 °C in Ar+4%H2, the redox conditions are sufficiently reducing so that metallic Fe is the stable phase. At lower temperatures the annealing conditions become less reducing and Fe3O4 becomes the stable phase. Transmission electron microscopy and x-ray diffraction studies established that each ?-Fe or Fe3O4 particle is a single crystal that is crystallographically aligned with respect to the YSZ host. Magneto-optical effects due to both the ?-Fe and Fe3O4 nanophase precipitates were found and characterized using magnetic circular dichroism. These magneto-optical effects have potential applications in integrated-optical devices.

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

2000-07-01

335

Involvement of superoxide radical in extracellular ferric reduction by iron-deficient bean roots. [Phadeolus vulgaris L. var Prelude  

SciTech Connect

The recent proposal of Tipton and Thowsen 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 Prelude) plants. The role of O/sub 2/ 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 O/sub 2/. However, in the presence of O/sub 2/ the reaction was partially inhibited by superoxide dismutase (SOD), which indicates a role for the superoxide radical, O/sub 2//sup -/, 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 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 O/sub 2//sup -/ may have in the acquisition of ferric iron by dicotyledonous plants.

Cakmak, I.; van de Wetering, D.A.M.; Marschner, H.; Bienfait, H.F.

1987-09-01

336

Enhanced anaerobic biodegradation of BTEX-ethanol mixtures in aquifer columns amended with sulfate, chelated ferric iron or nitrate  

E-print Network

, chelated ferric iron or nitrate Marcio L.B. Da Silva1 , Graciela M.L. Ruiz-Aguilar2 & Pedro J.J. Alvarez1Ā­Fe(III) or nitrate to enhance the biodegradation of BTEX and ethanol mixtures. The rapid biodegradation of ethanolĀ­Fe(III) or nitrate suppressed methanogenesis and significantly increased BTEX biodegradation efficiencies. Nev

Alvarez, Pedro J.

337

A bipolar membrane combined with ferric iron reduction as an efficient cathode system in microbial fuel cells.  

PubMed

There is a need for alternative catalysts for oxygen reduction in the cathodic compartment of a microbial fuel cell (MFC). In this study, we show that a bipolar membrane combined with ferric iron reduction on a graphite electrode is an efficient cathode system in MFCs. A flat plate MFC with graphite felt electrodes, a volume of 1.2 L and a projected surface area of 290 cm2 was operated in continuous mode. Ferric iron was reduced to ferrous iron in the cathodic compartment according to Fe(3+) + e(-) --> Fe2+ (E0 = +0.77 V vs NHE, normal hydrogen electrode). This reversible electron transfer reaction considerably reduced the cathode overpotential. The low catholyte pH required to keep ferric iron soluble was maintained by using a bipolar membrane instead of the commonly used cation exchange membrane. For the MFC with cathodic ferric iron reduction, the maximum power density was 0.86 W/m2 at a current density of 4.5 A/m2. The Coulombic efficiency and energy recovery were 80-95% and 18-29% respectively. PMID:16999089

Ter Heijne, Annemiek; Hamelers, Hubertus V M; De Wilde, Vinnie; Rozendal, René A; Buisman, Cees J N

2006-09-01

338

Bioavailability and the mechanisms of intestinal absorption of iron from ferrous ascorbate and ferric polymaltose in experimental animals  

Microsoft Academic Search

The comparative bioavailability from matching quantities of iron in the form of ferrous ascorbate or ferric polymaltose was defined in rats. Studies were carried out in the intact animals under basal conditions and also when requirements for this metal were either increased or decreased by manipulating stores or erythropoietic activity. No significant difference was found in the total quantity of

G. Johnson; P. Jacobs

1990-01-01

339

Oral Iron Absorption Test in Patients on CAPD: Comparison of Ferrous Sulfate and a Polysaccharide Ferric Complex  

Microsoft Academic Search

We prospectively compared the absorption of ferrous sulfate to that of a polysaccharide ferric complex (Niferex®) in 5 healthy controls and 7 stable patients on continuous ambulatory peritoneal dialysis (CAPD). All study subjects received an equivalent of 150 mg of elemental iron of either preparation, in a random fashion. After a baseline fasting serum iron level was obtained, the serum

Mohammad Tinawi; Kevin J. Martin; Bahar Bastani

1996-01-01

340

The abolition of the protective effect of Clostridium welchii type A antiserum by ferric iron  

PubMed Central

Intravenous injection of ferric ammonium citrate equivalent to 5 mg iron/kg abolished the protective effect of Clostridium welchii antiserum in guinea-pigs infected with Cl. welchii type A. In animals not given iron there was an abrupt cessation of growth 4–5 hours after infection. In those given iron bacterial growth was continuous and the animals died in 12–24 hours. In both of the animals there was always an excess of Cl. welchii alpha antitoxin in the plasma and tissues. Injection of iron did not interfere with phagocytosis of Cl. welchii. Iron abolished the protective effect of antiserum up to 6 hours after infection. It had no effect when given 8 hours after infection or later. PMID:4289804

Bullen, J. J.; Cushnie, G. H.; Rogers, Henry J.

1967-01-01

341

Treatment of antigen-induced arthritis in rabbits with dysprosium-165-ferric hydroxide macroaggregates  

SciTech Connect

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.

Zuckerman, J.D.; Sledge, C.B.; Shortkroff, S.; Venkatesan, P.

1989-01-01

342

Influence of ferric oxyhydroxide addition on biomethanation of waste activated sludge in a continuous reactor.  

PubMed

This study investigated the potential of enhancing the activity of iron-reducing bacteria (IRBs) to increase the biomethanation rate of waste activate sludge (WAS). The effects of biostimulation by ferric oxyhydroxide (Phase 2) and bioaugmentation with an enriched IRB consortium (Phase 3) were examined in a continuous anaerobic reactor treating WAS. Compared to the control operation (Phase 1), significant rises in methane yield (10.8-59.4%) and production rate (24.5-52.9%) were demonstrated by the biostimulation and bioaugmentation treatments. Visible structural changes were observed in bacterial community with the phases while not in archaeal community. Acinetobacter- and Spirochaetales-related populations were likely the major players driving anaerobic iron respiration and thus leading to enhanced biomethanation performance, in Phases 2 and 3, respectively. Our results suggest an interesting new potential for enhancing biomethanation of WAS. PMID:24929299

Baek, Gahyun; Kim, Jaai; Lee, Changsoo

2014-08-01

343

Simulation study of the ferrous ferric electron transfer at a metal--aqueous electrolyte interface  

SciTech Connect

We report a new simulation study of the rate of ferrous--ferric electron transfer at a metal electrolyte interface. In contrast with earlier work, new features in our study include a detailed account of the effects of the field associated with the charging of the electrode, inclusion of entropic effects in the calculated free energy barriers, and a study of the dependence of the relevant free energy surfaces on the distance of the ion from the electrode. The qualitative picture of the reaction mechanism which emerges is significantly more detailed than that in earlier work. The dominant factors in determining the rate and mechanisms of electron transfer are the distance dependence of the work function of the metal, the redox species concentration profile, and the electronic matrix element. Calculated free energy barriers are consistent with experimentally measured ones. We also estimate the equilibrium potential for this reaction from the model, and find it to be consistent with the experimental equilibrium potential.

Smith, B.B.; Halley, J.W. (School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455 (United States))

1994-12-15

344

Kinetics of the complexation of ferric iron with 8-hydroxyquinoline and KELEX 100  

SciTech Connect

The complexation reactions of ferric iron with 8-Hydroxyquinoline and KELEX-100 in both aqueous and methanol solutions were studied by using a stopped-flow spectrophotometer. In the aqueous solutions, the observed rate law was found to be first-order with respect to both iron(III) and oxine and inverse-first-order with respect to the hydrogen ion. While in the methanol solution, the rate law was first-order with respect to iron(III) and KELEX-100. Reaction pathes with the formation of the first complex, FeAS , from either FeT or Fe(OH)S were proposed to explain the observed rate law. The activation energies were found to be 5.5 kcal/g-mole and 15 kcal/g-mole for the aqueous and methanol solutions, respectively.

Ki, K.Y; Lemert, R.M.; Chang, H.K.

1987-01-01

345

Authigenic vivianite in Potomac River sediments: control by ferric oxy-hydroxides.  

USGS Publications Warehouse

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.

Hearn, P.P.; Parkhurst, D.L.; Callender, E.

1983-01-01

346

Iron sulphide formation in the ferric stearate Langmuir-Blodgett films  

NASA Astrophysics Data System (ADS)

Ferric stearate (FeSt) Langmuir-Blodgett (LB) films have been reacted chemically with H 2S gas for making iron sulphide within the organic matrix. Films, before and after the reaction with H 2S, have been analyzed with the X-ray reflectivity (XRR), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) studies. After sulphidation, more 'pinhole' defects form which changes the film morphology and the number of layers increases due to the rearrangement of the molecules. Formation of less ordered iron sulphide within the stearic acid multilayers after sulphidation increases the interfacial roughness that decreases the reflectivity. XPS analysis shows that polysulphide forms within the microenvironment of the FeSt LB films after reaction with H 2S whereas both mono and polysulphide are produced when the reaction occurs with FeSt in bulk.

Kundu, S.; Maidul Islam, A. K. M.; Mukherjee, M.

2011-01-01

347

Role of Ferric Reductases in Iron Acquisition and Virulence in the Fungal Pathogen Cryptococcus neoformans  

PubMed Central

Iron acquisition is critical for the ability of the pathogenic yeast Cryptococcus neoformans to cause disease in vertebrate hosts. In particular, iron overload exacerbates cryptococcal disease in an animal model, defects in iron acquisition attenuate virulence, and iron availability influences the expression of major virulence factors. C. neoformans acquires iron by multiple mechanisms, including a ferroxidase-permease high-affinity system, siderophore uptake, and utilization of both heme and transferrin. In this study, we examined the expression of eight candidate ferric reductase genes and their contributions to iron acquisition as well as to ferric and cupric reductase activities. We found that loss of the FRE4 gene resulted in a defect in production of the virulence factor melanin and increased susceptibility to azole antifungal drugs. In addition, the FRE2 gene was important for growth on the iron sources heme and transferrin, which are relevant for proliferation in the host. Fre2 may participate with the ferroxidase Cfo1 of the high-affinity uptake system for growth on heme, because a mutant lacking both genes showed a more pronounced growth defect than the fre2 single mutant. A role for Fre2 in iron acquisition is consistent with the attenuation of virulence observed for the fre2 mutant. This mutant also was defective in accumulation in the brains of infected mice, a phenotype previously observed for mutants with defects in high-affinity iron uptake (e.g., the cfo1 mutant). Overall, this study provides a more detailed view of the iron acquisition components required for C. neoformans to cause cryptococcosis. PMID:24478097

Saikia, Sanjay; Oliveira, Debora; Hu, Guanggan

2014-01-01

348

Role of ferric reductases in iron acquisition and virulence in the fungal pathogen Cryptococcus neoformans.  

PubMed

Iron acquisition is critical for the ability of the pathogenic yeast Cryptococcus neoformans to cause disease in vertebrate hosts. In particular, iron overload exacerbates cryptococcal disease in an animal model, defects in iron acquisition attenuate virulence, and iron availability influences the expression of major virulence factors. C. neoformans acquires iron by multiple mechanisms, including a ferroxidase-permease high-affinity system, siderophore uptake, and utilization of both heme and transferrin. In this study, we examined the expression of eight candidate ferric reductase genes and their contributions to iron acquisition as well as to ferric and cupric reductase activities. We found that loss of the FRE4 gene resulted in a defect in production of the virulence factor melanin and increased susceptibility to azole antifungal drugs. In addition, the FRE2 gene was important for growth on the iron sources heme and transferrin, which are relevant for proliferation in the host. Fre2 may participate with the ferroxidase Cfo1 of the high-affinity uptake system for growth on heme, because a mutant lacking both genes showed a more pronounced growth defect than the fre2 single mutant. A role for Fre2 in iron acquisition is consistent with the attenuation of virulence observed for the fre2 mutant. This mutant also was defective in accumulation in the brains of infected mice, a phenotype previously observed for mutants with defects in high-affinity iron uptake (e.g., the cfo1 mutant). Overall, this study provides a more detailed view of the iron acquisition components required for C. neoformans to cause cryptococcosis. PMID:24478097

Saikia, Sanjay; Oliveira, Debora; Hu, Guanggan; Kronstad, James

2014-02-01

349

Acidibacter ferrireducens gen. nov., sp. nov.: an acidophilic ferric iron-reducing gammaproteobacterium.  

PubMed

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

Falagįn, Carmen; Johnson, D Barrie

2014-11-01

350

Ferric carboxymaltose: A revolution in the treatment of postpartum anemia in Indian women  

PubMed Central

Objectives: The objective of the present study is to compare the safety and efficacy of ferric carboxymaltose (FCM), intravenous (IV) iron sucrose and oral iron in the treatment of post = partum anemia (PPA). Materials and Methods: A total of 366 women admitted to SCB Medical College, Cuttack between September 2010 and August 2012 suffering from PPA hemoglobin (Hb) <10 g/dL were randomly assigned to receive either oral iron or IV FCM or iron sucrose. FCM, IV iron sucrose, and oral iron were given as per the protocol. Changes in hemoglobin (Hb) and serum ferritin levels at 2 and 6 weeks after treatment were measured and analyzed using ANOVA. Adverse effects to drug administration were also recorded. Results: A statistically significant increase in Hb and serum ferritin level were observed in all three groups, but the increase in FCM group was significantly higher (P < 0.0001) than conventional iron sucrose and oral iron group. The mean increase in Hb after 2 weeks was 0.8, 2.4, and 3.2 g/dL and 2.1, 3.4, and 4.4 g/dL at 6 weeks in oral iron, iron sucrose and FCM groups, respectively. The mean increase in serum ferritin levels after 2 weeks was 2.5, 193.1, and 307.1 and 14.2, 64, and 106.7 ng/mL after 6 weeks in oral iron, iron sucrose and FCM groups, respectively. Adverse drug reactions were significantly less (P < 0.001) in FCM group when compared with other two groups. Conclusion: Ferric carboxymaltose elevates Hb level and restores iron stores faster than IV iron sucrose and oral iron, without any severe adverse reactions. There was better overall satisfaction reported by the patients who received FCM treatment.

Rathod, Setu; Samal, Sunil K; Mahapatra, Purna C; Samal, Sunita

2015-01-01

351

Investigations of Vibrational Coherence in the Low-Frequency Region of Ferric Heme Proteins  

PubMed Central

Femtosecond coherence spectroscopy is applied to a series of ferric heme protein samples. The low-frequency vibrational spectra that are revealed show dominant oscillations near 40 cm?1. MbCN is taken as a typical example of a histidine-ligated, six-coordinate, ferric heme and a comprehensive spectroscopic analysis is carried out. The results of this analysis reveal a new heme photoproduct species, absorbing near 418 nm, which is consistent with the photolysis of the His93 axial ligand. The photoproduct undergoes subsequent rebinding/recovery with a time constant of ?4 ps. The photoproduct lineshapes are consistent with a photolysis quantum yield of 75–100%, although the observation of a relatively strong six-coordinate heme coherence near 252 cm?1 (assigned to ?9 in the MbCN Raman spectrum) suggests that the 75% lower limit is much more likely. The phase and amplitude excitation profiles of the low-frequency mode at 40 cm?1 suggest that this mode is strongly coupled to the MbCN photoproduct species and it is assigned to the doming mode of the transient penta-coordinated material. The absolute phase of the 40 cm?1 mode is found to be ?/2 on the red side of 418 nm and it jumps to 3?/2 as excitation is tuned to the blue side of 418 nm. The absolute phase of the 40 cm?1 signal is not explained by the standard theory for resonant impulsive stimulated Raman scattering. New mechanisms that give a dominant momentum impulse to the resonant wavepacket, rather than a coordinate displacement, are discussed. The possibilities of heme iron atom recoil after photolysis, as well as ultrafast nonradiative decay, are explored as potential ways to generate the strong momentum impulse needed to understand the phase properties of the 40 cm?1 mode. PMID:18065461

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

2008-01-01

352

Proton coupling in the ligand-binding reaction of ferric cytochrome P-450 from Pseudomonas putida  

SciTech Connect

Effects of pH on the ligand-binding reactions of ferric heme in cytochrome P-450 from Pseudomonas putida (camphor 5-monooxygenase, EC 1.14.15.1) were studied by using cyanide, N-methylimidazole, pyridine, and ethylisocyanide as ligands. In all cases, affinity of the ferric heme for the ligand was found to increase as pH of the medium was raised from around 6 to 9. Depending on the ligand, the increase was 10- to 1000-fold and the shapes of their pH-affinity curves were remarkably different. Analyses such pH profiles disclosed the presence of a dissociable group in the enzyme with a pK value of approximately 9.5 and that its ionization greatly enhanced the affinity of the heme for ligands. When a dissociable ligand such as hydrogen cyanide and N-methylimidazole was used, the dissociated form of the ligand had a higher affinity toward the heme than the undissociated form. The shapes of the pH-affinity curves were successfully simulated as overlapping curves of ionization reactions of the ligand and the dissociable group. In addition, size of the ligand molecule was shown to be also important in the binding reaction: relatively large molecules such as pyridine, ethylisocyanide, and N-methylimidazole bound to the enzyme in a competitive manner against d-camphor concentration, whereas the binding of a smaller molecule such as cyanide was inhibited by the substrate in a noncompetitive manner. On the basis of these findings, control mechanisms for the ligand-binding reactions of the cytochrome P-450 from P. putida are discussed.

Totani, K.; Iizuka, T.; Shimada, H.; Makino, R.; Ishimura, Y.

1983-04-01

353

Fabrication of novel chemosensors composed of rhodamine derivative for the detection of ferric ion and mechanism studies on the interaction between sensor and ferric ion.  

PubMed

Although many rhodamine based fluorescence sensors were reported to detect metal ions with high sensitivity and selectivity, there are very few reports available to study the mechanisms of detection and the interaction between probe and metal ions. This paper aims to detect ferric ions by novel fluorescence chemosensors and study the mechanisms in detail. A novel probe AD-MAH-RhB was designed and synthesized from rhodamine B (RhB), adamantyl (AD), ethylene diamine and maleic anhydride (MAH). AD-MAH-RhB could detect Fe(3+) in aqueous solutions. The mechanism was explored by the HSAB principle, FTIR and mass spectra. The results suggested that Fe(3+) bound with amine and oxygen atoms in AD-MAH-RhB to form a complex composed of a 2?:?1 stoichiometry of Fe(3+) and the probe. Moreover, computational simulations were employed to further investigate the detection mechanism. The calculated results showed that Fe(3+) could conjugate with AD-MAH-RhB probe to form a stable complex, which was induced by synergetic effects of the suitable space and distance of van der Waals forces. However, Hg(2+) was found to disturb this detection and form a complex with 1?:?2 stoichiometry of Hg(2+) and AD-MAH-RhB. Then, another probe, ?-cyclodextrin modified polymaleic anhydride (PMAH-CD) including AD-MAH-RhB (PMAH-CD/AD-MAH-RhB) was fabricated by inclusion interaction between CD and AD. PMAH-CD@AD-MAH-RhB showed high selectivity and sensitivity to Fe(3+) in the aqueous solution by eliminating the interruption of Hg(2+) possibly due to the high hydrogen interaction among the probes to inhibit the stable form complex with Hg(2+). PMID:25574522

Shi, Dongjian; Ni, Ming; Luo, Jing; Akashi, Mitsuru; Liu, Xiaoya; Chen, Mingqing

2015-02-01

354

Electrocatalytic characteristics of uric acid oxidation at graphite–zeolite-modified electrode doped with iron (III)  

Microsoft Academic Search

A new method is developed for the catalytic oxidation of uric acid at graphite–zeolite-modified electrode doped with iron (III) (Fe3+Y\\/ZCME). Iron (III) exchanged in zeolite Y act as catalyst to oxidize uric acid. First, the electrochemical behavior of iron (III) incorporated in the zeolite Y-modified electrode was studied. The results illustrate that diffusion controls the ferric\\/ferrous redox process at the

M. Mazloum Ardakani; Z. Akrami; H. Kazemian; H. R. Zare

2006-01-01

355

Gold and iron oxide associations under supergene conditions: An experimental approach  

Microsoft Academic Search

-The interaction of gold hydroxo-chloro complexes with iron oxides (ferrihydrites, goethites) during coprecipitation experiments is investigated. Chemical analyses of solids and solutions are coupled with a detailed characterization of the iron oxides with various methods, including X-ray diffraction, High Resolution Transmission Electron Microscopy (HRTEM), and Mössbauer spectroscopy. HCl solutions containing varying amounts of AuCl4- and ferric nitrate were titrated to

Catherine Greffié; Marc F. Benedetti; Claude Parron; Marc Amouric

1996-01-01

356

Comparative stability of the bioresorbable ferric crosslinked hyaluronic acid adhesion prevention solutions.  

PubMed

The Intergel® ferric crosslinked hyaluronate (FeHA) adhesion prevention solution (APS) (FDA) is associated with serious post-operative complications (Henley, http://www.lawyersandsettlements.com/features/gynecare-intergel/intergel-timeline.html, 2007; FDA, 2003; Roman et al., Fertil Steril 2005, 83 Suppl 1:1113-1118; Tang et al., Ann Surg 2006;243(4):449-455; Wiseman, Fertil Steril 2006;86(3):771; Wiseman, Fertil Steril 2006;85(4):e7). This prompted us to examine the in situ stability of crosslinked HA materials to hyaluronidase lyase degradation. Variables such as ferric ionic crosslink density, HA concentration, gel geometry, and molecular weight (MW) of HA polymer were studied. Various formulations of the crosslinked "in house" [Isayeva et al., J Biomed Mater Res: Part B - Appl Biomater 2010, 95B (1):9-18] FeHA (0.5%, w/v; 30, 50, 90% crosslinked), the Intergel® FeHA (0.5%, w/v; 90%), and the non-crosslinked HA (0.05-0.5%, w/v) were degraded at a fixed activity of hyaluronidase lyase from Streptomyces hyalurolyticus (Hyase) at 37°C over time according to the method [Payan et al., J Chrom B: Biomed Sci Appl 1991;566(1):9-18]. Under our conditions, the data show that the crosslink density affects degradation the most, followed by HA concentration and then gel geometry. We found that MW has no effect. Our results are one possible explanation of the observations that the Intergel® FeHA APS (0.5%, w/v; 90%) material persisted an order of magnitude longer than expected [t1/2 = 500 hrs vs. t1/2 = 50 hrs (FDA; Johns et al., Fertil Steril 1997;68(1):37-42)]. These data also demonstrate the sensitivity of the in vitro hyaluronidase assay to predict the in situ stability of crosslinked HA medical products as previously reported [Sall et al., Polym Degrad Stabil 2007;92(5):915-919]. PMID:23559362

Luu, Hoan-My Do; Chen, Angela; Isayeva, Irada S

2013-08-01

357

Spectral study of the interaction between 2-pyridinecarbaldehyde-p-phenyldihydrazone and ferric iron and its analytical application  

NASA Astrophysics Data System (ADS)

The synthesis and spectral characterization of a schiff base, 2-pyridinecarbaldehyde-p-phenylenedihydrazone (short for 2PC-PPH), were described. It was found that ferric ion (Fe3+) could selectively quench the fluorescence of 2PC-PPH, whereas many other metal ions, such as Mn2+, Zn2+, Cu2+, K+, Al3+, Ca2+, Ni2+, Co2+, Cr3+ and Fe2+, could not quench its fluorescence. Based on this, a sensitive method for ferric ion selective detection was established. Under the optimum conditions, the decreasing fluorescence intensity of 2PC-PPH is proportional to the concentration of Fe3+ within the range of 6.0 × 10-7-1.0 × 10-5 mol L-1. The detection limit (3?) for Fe3+ determination is 3.6 × 10-7 mol L-1. The proposed method was successfully applied to determine iron in tea and milk powder.

Zhou, Quanying; Liu, Weizhou; Chang, Lin; Chen, Fang

2012-06-01

358

The Enzyme-mimic Activity of Ferric Nano-Core Residing in Ferritin and Its Biosensing Applications  

SciTech Connect

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.

Tang, Zhiwen; Wu, Hong J.; Zhang, Youyu; Li, Zhaohui; Lin, Yuehe

2011-11-15

359

Two Bifunctional Enzymes with Ferric Reduction Ability Play Complementary Roles during Magnetosome Synthesis in Magnetospirillum gryphiswaldense MSR-1  

PubMed Central

The bacterial strain Magnetospirillum gryphiswaldense MSR-1 does not produce siderophores, but it absorbs a large amount of ferric iron and synthesizes magnetosomes. We demonstrated previously the presence of six types of ferric reductase isozymes (termed FeR1 through FeR6) in MSR-1. Of these isozymes, FeR5 was the most abundant and FeR6 showed the highest ferric reductase activity. In the present study, we cloned the fer5 and fer6 genes from MSR-1 and expressed them separately in Escherichia coli. FeR5 and FeR6 were shown to be bifunctional enzymes through analysis of amino acid sequence homologies, structural predictions (using data from GenBank), and detection of enzyme activities. FeR5 is a thioredoxin reductase and FeR6 is a flavin reductase, in addition to being ferric reductases. To elucidate the functions of the enzymes, we constructed two single-gene-deletion mutant strains (?fer5 and ?fer6 mutants) and a double-gene-deletion mutant strain (?fer5 ?fer6 [?fer5+6] mutant) along with its complemented strains (C5 and C6). An evaluation of phenotypic and physiological properties did not reveal significant differences between the wild-type and single-gene-deletion strains, whereas the double-gene-deletion strain showed reduced iron absorption and no magnetosome synthesis. Complementation of the double-gene-deletion strain using either fer5 or fer6 resulted in the partial recovery of magnetosome synthesis. Quantitative real-time PCR analysis of fer5 and fer6 transcriptional levels in the wild-type and complemented strains demonstrated consistent transcription of the two genes and confirmed that FeR5 and FeR6 are bifunctional enzymes that play complementary roles during the process of magnetosome synthesis in MSR-1. PMID:23243303

Zhang, Chan; Meng, Xia; Li, Ningxiao; Wang, Wei; Sun, Yuan; Jiang, Wei; Guan, Guohua

2013-01-01

360

Garlic oil ameliorates ferric nitrilotriacetate (Fe-NTA)-induced damage and tumor promotion: Implications for cancer prevention  

Microsoft Academic Search

Intraperitoneal injection of ferric nitrilotriacetate (Fe-NTA) to rats and mice results in iron-induced free radical injury and cancer in kidneys. This study was designed to investigate the effects of garlic oil on Fe-NTA-induced damage and tumor promotion. Pretreatment of rats with garlic oil at a dose regimen of 50–100mg\\/kg body weight for a week significantly and dose dependently protected against

Mukesh Kumar Agarwal; Mohammad Iqbal; Mohammad Athar

2007-01-01

361

A Novel Intravenous Iron Formulation for Treatment of Anemia in Inflammatory Bowel Disease: The Ferric Carboxymaltose (FERINJECT®) Randomized Controlled Trial  

Microsoft Academic Search

BACKGROUND AIMS:Anemia is a common complication of inflammatory bowel diseases (IBD) This multicenter study tested the noninferiority and safety of a new intravenous iron preparation, ferric carboxymaltose (FeCarb), in comparison with oral ferrous sulfate (FeSulf) in reducing iron deficiency anemia (IDA) in IBD.METHODS:Two hundred patients were randomized in a 2:1 ratio (137 FeCarb:63 FeSulf) to receive FeCarb (maximum 1,000 mg

Stefanie Kulnigg; Simeon Stoinov; Vladimir Simanenkov; Larisa V. Dudar; Waldemar Karnafel; Luis Chaires Garcia; Alicia M. Sambuelli; Geert D'Haens; Christoph Gasche

2008-01-01

362

Arsenic Release from Natural and Anthropogenic Metal (Hydr)Oxide Sorbents  

NASA Astrophysics Data System (ADS)

Arsenic is a common constituent of soils and minerals throughout the world and is, at a global scale, arguably the most serious inorganic drinking water contaminant. The talk will focus on the results of studies to elucidate the biogeochemical conditions that lead to enhanced release and mobility of arsenic in aqueous streams. It will be suggested that when arsenic is (relatively) stably bound to metal (hydr)oxides in an oxic environment, the redox shift conditions which lead to arsenic mobilization in natural ground waters are also present in many of the locations where the arsenic-bearing residuals from water treatment processes are disposed. In oxic environments a large fraction of the arsenic is commonly present as an adsorbed species associated with metal (hydr)oxides, particularly ferric (hydr)oxides. Likewise, ferric (hydr)oxide based sorbents are by far the most common method utilized for removing arsenic from drinking water. It has been known for many years that the mobilization of arsenic from these materials most dramatically occurs when moderate to low redox conditions (-100 to -300 mV) occur and this release has been attributed to the reductive dissolution of the ferric sorbent. However, our and others' recent work suggests that most of the arsenic release in such conditions is decoupled from the iron release and the presence or absence of the reductive dissolution of ferric (hydr)oxides has little bearing on the overall magnitude of arsenic mobilization. There are many practical ramifications of this result, one of the simplest is that if arsenic is sorbed to a non- redox sensitive solid surface (of say a zirconium or lanthanum oxide), rather than an iron surface, it will not reduce the lability of arsenic when the solid is exposed to reducing conditions. Furthermore, when reducing conditions are imposed on ferric (hydr)oxide sorbent systems, the reductive dissolution of ferric species feeds the precipitation of mixed iron and ferrous iron solids whose rate of formation, degree of crystallinity, and sorptive capacity is a function of the concentration of arsenic species in the system.

Ela, W. P.; Sįez, E.

2008-12-01

363

Ferric Hydrogensulfate [Fe(HSO4)3] As a Reusable Heterogeneous Catalyst for the Synthesis of 5-Substituted-1H-Tetrazoles and Amides  

PubMed Central

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

Eshghi, Hossein; Seyedi, Seyed Mohammad; Zarei, Elaheh Rahimi

2011-01-01

364

Leaching of Arsenic from Granular Ferric Hydroxide Residuals under Mature Landfill Conditions  

PubMed Central

Most arsenic bearing solid residuals (ABSR) from water treatment will be disposed in non-hazardous landfills. The lack of an appropriate leaching test to predict arsenic mobilization from ABSR creates a need to evaluate the magnitude and mechanisms of arsenic release under landfill conditions. This work studies the leaching of arsenic and iron from a common ABSR, granular ferric hydroxide, in a laboratory-scale column that simulates the biological and physicochemical conditions of a mature, mixed solid waste landfill. The column operated for approximately 900 days and the mode of transport as well as chemical speciation of iron and arsenic changed with column age. Both iron and arsenic were readily mobilized under the anaerobic, reducing conditions. During the early stages of operation, most arsenic and iron leaching (80% and 65%, respectively) was associated with suspended particulate matter and iron was lost proportionately faster than arsenic. In later stages, while the rate of iron leaching declined, the arsenic leaching rate increased greater than 7-fold. The final phase was characterized by dissolved species leaching. Future work on the development of standard batch leaching tests should take into account the dominant mobilization mechanisms identified in this work: solid associated transport, reductive sorbent dissolution, and microbially mediated arsenic reduction. PMID:17051802

Ghosh, Amlan; Mukiibi, Muhammed; Sįez, A. Eduardo; Ela, Wendell P.

2008-01-01

365

Permeability properties of a large gated channel within the ferric enterobactin receptor, FepA.  

PubMed Central

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

Liu, J; Rutz, J M; Feix, J B; Klebba, P E

1993-01-01

366

Passive immunization by recombinant ferric enterobactin protein (FepA) from Escherichia coli O157  

PubMed Central

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

Larrie-Bagha, Seyed Mehdi; Rasooli, Iraj; Mousavi-Gargari, Seyed Latif; Rasooli, Zohreh; Nazarian, Shahram

2013-01-01

367

The fate of Microcystis aeruginosa cells during the ferric chloride coagulation and flocs storage processes.  

PubMed

Microcystis blooms could cause severe problems for drinking water supplies with their associated microcystins (MCs). As the majority of MCs are retained inside the cells, the effective removal of the intact Microcystis cells to avoid the release of additional MCs plays an important role in drinking water treatment. This study evaluated the effect of ferric chloride (FeCl3) coagulation and the flocs storage process on the integrity of Microcystis aeruginosa cells and the intracellular MCs release (and possible degradation) in both processes. Multiple analysis techniques including scanning electron microscopy and chlorophyll fluorescence were used to assess the integrity of M. aeruginosa. In the coagulation process, the coagulant dosage and mechanical actions caused no cell damage, and all the cells remained intact. Furthermore, 100?mg/L FeCl3 was effective in removing the extracellular MCs. In the flocs storage process, a number of intracellular MCs were released into the supernatant, but the cells remained viable up to 10?d. PMID:25241771

Li, Xiuqing; Pei, Haiyan; Hu, Wenrong; Meng, Panpan; Sun, Feng; Ma, Guixia; Xu, Xiangchao; Li, Yuezhong

2015-04-01

368

Overproduction in Escherichia coli and Characterization of a Soybean Ferric Leghemoglobin Reductase.  

PubMed Central

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

Ji, L.; Becana, M.; Sarath, G.; Shearman, L.; Klucas, R. V.

1994-01-01

369

Uptake of iron by isolated rat hepatocytes from a hydrophilic impermeant ferric chelate, Fe(III)-DTPA.  

PubMed

We studied uptake of iron from Fe(III)-diethylenetriamine pentaacetate (DTPA) in isolated rat hepatocytes. This uptake is specific with an affinity of 600 nM and shows an optimum pH of 6. The specificity is indicated by inhibition by ferric citrate and diferric transferrin. Iron uptake from Fe(III)-DTPA is completely inhibited by trypsinization of the cell surface, by strong impermeant ferric chelators (DTPA, apo-transferrin, polymer-conjugated desferrioxamine), both hexacyanoferrates, copper and zinc, and partly by dipyridyl, manganese, cobalt, N-ethylmaleimide, and citrate. The lysosomotropic agent chloroquin inhibits weakly; proton pump inhibitors are without effect. Ascorbate and Tiron both effectively stimulate the uptake and also mobilize iron from DTPA in vitro. Approximately 75% of the freshly acquired intracellular iron is found in ferritin even after uptake at lowered temperature (16 degrees C). We conclude that a rate-limiting mobilization of iron from the DTPA chelate by a cell-surface activity is required before iron can actually enter the cell. This can be enhanced by mediators of iron release, but does not seem to require reduction of iron. The use of DTPA as chelator offers the possibility of studying this putative activity because the Fe(III)-DTPA chelate is stable in the presence of transferrin or desferroxamine, in contrast to ferric citrate or Fe(NTA)2. PMID:8611022

Scheiber, B; Goldenberg, H

1996-02-15

370

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

Microsoft Academic Search

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 ?380,000m3 of mining waste. The tailings and the discharged water have circumneutral pH values (7.0±0.6) because the acidity generated by the

Juraj Majzlan; Bronislava Lalinskį; Martin Chovan; L’ubomķr Jurkovi?; Stanislava Milovskį; Jörg Göttlicher

2007-01-01

371

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 ...

372

Enhanced photocatalytic activity of sprayed Au doped ferric oxide thin films for salicylic acid degradation in aqueous medium.  

PubMed

Various doping percentage of Au were successfully introduced into the Fe2O3 photocatalysts via a spray pyrolysis method different. The effect of Au doping on photoelectrochemical, structural, optical and morphological properties of these deposited thin films is studied. The PEC characterization shows that, the photocurrent increases gradually with increasing Au content initially up to 2at.% indicating the maximum values of short circuit current (Isc) and open circuit voltage (Voc) are (Isc=90?A and Voc=220.5mV) and then decreases after exceeding the optimal Au doping content. Therefore, the photocurrent of Au doped Fe2O3 photocatalysts can be adjusted by the Au content. Deposited films are polycrystalline with a rhombohedral crystal structure having (104) preferred orientation. SEM and AFM images show deposited thin films are compact and uniform. The photocatalytic activities of the Fe2O3 and Au:Fe2O3 photocatalyst were evaluated by photoelectrocatalytic degradation of salicylic acid under sunlight irradiation. The results show that the Au:Fe2O3 thin film photocatalyst exhibited about 45% more degradation of pollutants than the pure Fe2O3. Thus, in Au doped Fe2O3 photocatalysts, the interaction between Au and Fe2O3 reduces the recombination of photogenerated charge carriers and improve the photocatalytic activity. PMID:25496876

Mahadik, M A; Shinde, S S; Kumbhar, S S; Pathan, H M; Rajpure, K Y; Bhosale, C H

2015-01-01

373

Photocatalytic activity of ferric oxide/titanium dioxide nanocomposite films on stainless steel fabricated by anodization and ion implantation  

NASA Astrophysics Data System (ADS)

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 atoms·cm-2 and then annealed in air at 450°C 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.

Zhan, Wei-ting; Ni, Hong-wei; Chen, Rong-sheng; Yue, Gao; Tai, Jun-kai; Wang, Zi-yang

2013-08-01

374

Oxidation of basaltic tephras: Influence on reflectance in the 1 micron region  

NASA Technical Reports Server (NTRS)

As part of a ongoing study into the products of hydrovolcanism, tuffs were examined from the Cerro Colorado and Pavant Butte tuff cones. The former resides in the northeastern corner of the Pinacate Volcanic Field in Sonara, Mexico and the latter is in the Black Rock Desert of southern Utah. Numerous samples were collected and many of these had their Vis/IR reflectance measured. It seems likely that in the palagonite tuffs there is a combination of nanocrystalline ferric oxide phases contributing to the UV absorption edge, but not to the 1 micron band, plus more crystalline ferric oxides which do contribute to that band as well as ferrous iron within unaltered sideromelane which is skewing the band center to longer wavelengths. This work has implications for the study of Mars. The present work indicates that when ferrous and ferric iron phases are both present, their combined spectral contribution is a single band in the vicinity of 1 micron. The center, depth, and width of that feature has potential to be used to gauge the relative proportions of ferrous and ferric iron phases.

Farrand, William H.; Singer, Robert B.

1991-01-01

375

The Martian oxygen surface sink and its implications for the oxidant extinction depth  

NASA Astrophysics Data System (ADS)

Based on the evolution of the atmosphere-surface-interaction of Mars, one might expect a large oxygen surface sink over geologic time-scales. Due to intense oxidation of inorganic matter this led to the formation of considerable amounts of sulfates and ferric oxides on Mars. To model this effect several factors have to be under consideration: Inorganic composition of the Martian soil, amount of incorporated oxygen, meteoritic gardening, and the oxidant extinction depth. The oxygen incorporation has further implications for the assumed oxidant extinction depth, which is an important parameter to determine required sampling depths on Mars to find putative organic material.

Kolb, C.; Lammer, H.; Abart, R.; Ellery, A.; Edwards, H. G. M.; Cockell, C. S.; Patel, M. R.

2002-11-01

376

Method for fluorination of uranium oxide  

DOEpatents

Highly pure uranium hexafluoride is made from uranium oxide and fluorine. The uranium oxide, which includes UO.sub.3, UO.sub.2, U.sub.3 O.sub.8 and mixtures thereof, is introduced together with a small amount of a fluorine-reactive substance, selected from alkali chlorides, silicon dioxide, silicic acid, ferric oxide, and bromine, into a constant volume reaction zone. Sufficient fluorine is charged into the zone at a temperature below approximately 0.degree. C. to provide an initial pressure of at least approximately 600 lbs/sq. in. at the ambient atmospheric temperature. The temperature is then allowed to rise in the reaction zone until reaction occurs.

Petit, George S. (Oak Ridge, TN)

1987-01-01

377

Nitric oxide donor superparamagnetic iron oxide nanoparticles.  

PubMed

This work reports a new strategy for delivering nitric oxide (NO), based on magnetic nanoparticles (MNPs), with great potential for biomedical applications. Water-soluble magnetic nanoparticles were prepared through a co-precipitation method by using ferrous and ferric chlorides in acidic solution, followed by a mercaptosuccinic acid (MSA) coating. The thiolated nanoparticles (SH-NPs) were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM), and vibrating sample magnetometry (VSM). The results showed that the SH-NPs have a mean diameter of 10nm and display superparamagnetic behavior at room temperature. Free thiol groups on the magnetite surface were nitrosated through the addition of an acidified nitrite solution, yielding nitrosated magnetic nanoparticles (SNO-NPs). The amount of NO covalently bound to the nanoparticles surface was evaluated by chemiluminescense. The SNO-NPs spontaneously released NO in aqueous solution at levels required for biomedical applications. This new magnetic NO-delivery vehicle has a great potential to generate desired amounts of NO directed to the target location. PMID:25427482

Molina, Miguel M; Seabra, Amedea B; de Oliveira, Marcelo G; Itri, Rosangela; Haddad, Paula S

2013-03-01

378

Solubility products of amorphous ferric arsenate and crystalline scorodite (FeAsO 4 · 2H 2O) and their application to arsenic behavior in buried mine tailings  

NASA Astrophysics Data System (ADS)

Published solubility data for amorphous ferric arsenate and scorodite have been reevaluated using the geochemical code PHREEQC with a modified thermodynamic database for the arsenic species. Solubility product calculations have emphasized measurements obtained under conditions of congruent dissolution of ferric arsenate (pH < 3), and have taken into account ion activity coefficients, and ferric hydroxide, ferric sulfate, and ferric arsenate complexes which have association constants of 10 4.04 (FeH 2AsO 42+), 10 9.86 (FeHAsO 4+), and 10 18.9 (FeAsO 4). Derived solubility products of amorphous ferric arsenate and crystalline scorodite (as log Ksp) are -23.0 ± 0.3 and -25.83 ± 0.07, respectively, at 25 °C and 1 bar pressure. In an application of the solubility results, acid raffinate solutions (molar Fe/As = 3.6) from the JEB uranium mill at McClean Lake in northern Saskatchewan were neutralized with lime to pH 2-8. Poorly crystalline scorodite precipitated below pH 3, removing perhaps 98% of the As(V) from solution, with ferric oxyhydroxide (FO) phases precipitated starting between pH 2 and 3. Between pH 2.18 and 7.37, the apparent log Ksp of ferric arsenate decreased from -22.80 to -24.67, while that of FO (as Fe(OH) 3) increased from -39.49 to -33.5. Adsorption of As(V) by FO can also explain the decrease in the small amounts of As(V)(aq) that remain in solution above pH 2-3. The same general As(V) behavior is observed in the pore waters of neutralized tailings buried for 5 yr at depths of up to 32 m in the JEB tailings management facility (TMF), where arsenic in the pore water decreases to 1-2 mg/L with increasing age and depth. In the TMF, average apparent log Ksp values for ferric arsenate and ferric hydroxide are -25.74 ± 0.88 and -37.03 ± 0.58, respectively. In the laboratory tests and in the TMF, the increasing crystallinity of scorodite and the amorphous character of the coexisting FO phase increases the stability field of scorodite relative to that of the FO to near-neutral pH values. The kinetic inability of amorphous FO to crystallize probably results from the presence of high concentrations of sulfate and arsenate.

Langmuir, Donald; Mahoney, John; Rowson, John

2006-06-01

379

Microwave Assisted Synthesis of Iron(III) Oxyhydroxides/Oxides Characterized Using Transmission Electron Microscopy, X-ray Diffraction, and X-ray Absorption Spectroscopy  

PubMed Central

Microwave assisted synthesis of iron oxide/oxyhydroxide nanophases was conducted using iron(III) chloride titrated with sodium hydroxide at seven different temperatures from 100°C to 250°C with pulsed microwaves. From the XRD results, it was determined that there were two different phases synthesized during the reactions which were temperature dependent. At the lower temperatures, 100°C and 125°C, it was determined that an iron oxyhydroxide chloride was synthesized. Whereas, at higher temperatures, at 150°C and above, iron(III) oxide was synthesized. From the XRD, we also determined the FWHM and the average size of the nanoparticles using the Scherrer equation. The average size of the nanoparticles synthesized using the experimental conditions were 17, 21, 12, 22, 26, 33, 28 nm, respectively for the reactions from 100°C to 250°C. The particles also had low anisotropy indicating spherical nanoparticles, which was later confirmed using TEM. Finally, XAS studies show that the iron present in the nanophase was present as iron(III) coordinated to six oxygen atoms in the first coordination shell. The higher coordination shells also conform very closely to the ideal or bulk crystal structures. PMID:20161181

Parsons, J.G.; Luna, C.; Botez, C.E.; Elizalde, J.; Gardea-Torresdey, J.L.

2009-01-01

380

Iron-reducing bacteria accumulate ferric oxyhydroxide nanoparticle aggregates that may support planktonic growth  

PubMed Central

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

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

381

Ferric Uptake Regulator and Its Role in the Pathogenesis of Nontypeable Haemophilus influenzae  

PubMed Central

Nontypeable Haemophilus influenzae (NTHi) is a commensal microorganism of the human nasopharynx, and yet is also an opportunistic pathogen of the upper and lower respiratory tracts. Host microenvironments influence gene expression patterns, likely critical for NTHi persistence. The host sequesters iron as a mechanism to control microbial growth, and yet iron limitation influences gene expression and subsequent production of proteins involved in iron homeostasis. Careful regulation of iron uptake, via the ferric uptake regulator Fur, is essential in multiple bacteria, including NTHi. We hypothesized therefore that Fur contributes to iron homeostasis in NTHi, is critical for bacterial persistence, and likely regulates expression of virulence factors. Toward this end, fur was deleted in the prototypic NTHi clinical isolate, 86-028NP, and we assessed gene expression regulated by Fur. As expected, expression of the majority of genes that encode proteins with predicted roles in iron utilization was repressed by Fur. However, 14 Fur-regulated genes encode proteins with no known function, and yet may contribute to iron utilization or other biological functions. In a mammalian model of human otitis media, we determined that Fur was critical for bacterial persistence, indicating an important role for Fur-mediated iron homeostasis in disease progression. These data provide a profile of genes regulated by Fur in NTHi and likely identify additional regulatory pathways involved in iron utilization. Identification of such pathways will increase our understanding of how this pathogen can persist within host microenvironments, as a common commensal and, importantly, as a pathogen with significant clinical impact. PMID:23381990

Santana, Estevan A.; Szelestey, Blake R.; Newsom, David E.; White, Peter; Mason, Kevin M.

2013-01-01

382

Effect of Ammonium and Nitrate on Ferric Chelate Reductase and Nitrate Reductase in Vaccinium Species  

PubMed Central

• Background and Aims Most Vaccinium species have strict soil requirements for optimal growth, requiring low pH, high iron availability and nitrogen primarily in the ammonium form. These soils are limited and are often located near wetlands. Vaccinium arboreum is a wild species adapted to a wide range of soils, including high pH, low iron, and nitrate?containing soils. This broader soil adaptation in V. arboreum may be related to increased efficiency of iron or nitrate uptake compared with the cultivated Vaccinium species. • Methods Nitrate, ammonium and iron uptake, and nitrate reductase (NR) and ferric chelate reductase (FCR) activities were compared in two Vaccinium species grown hydroponically in either nitrate or ammonia, with or without iron. The species studied were the wild V. arboreum and the cultivated V. corymbosum interspecific hybrid, which exhibits the strict soil requirements of most Vaccinium species. • Key Results Ammonium uptake was significantly greater than nitrate uptake in both species, while nitrate uptake was greater in the wild species, V. arboreum, compared with the cultivated species, V. corymbosum. The increased nitrate uptake in V. arboreum was correlated with increased root NR activity compared with V. corymbosum. The lower nitrate uptake in V. corymbosum was reflected in decreased plant dry weight in this species compared with V. arboreum. Root FCR activity increased significantly in V. corymbosum grown under iron?deficient conditions, compared with the same species grown under iron?sufficient conditions or with V. arboreum grown under either iron condition. • Conclusions. V. arboreum appears to be more efficient in acquiring nitrate compared with V. corymbosum, possibly due to increased NR activity and this may partially explain the wider soil adaptation of V. arboreum. PMID:14980973

POONNACHIT, U.; DARNELL, R.

2004-01-01

383

Clinical experience with ferric carboxymaltose in the treatment of cancer- and chemotherapy-associated anaemia  

PubMed Central

Background Intravenous (i.v.) iron can improve anaemia of chronic disease and response to erythropoiesis-stimulating agents (ESAs), but data on its use in practice and without ESAs are limited. This study evaluated effectiveness and tolerability of ferric carboxymaltose (FCM) in routine treatment of anaemic cancer patients. Patients and methods Of 639 patients enrolled in 68 haematology/oncology practices in Germany, 619 received FCM at the oncologist's discretion, 420 had eligible baseline haemoglobin (Hb) measurements, and 364 at least one follow-up Hb measurement. Data of transfused patients were censored from analysis before transfusion. Results The median total iron dose was 1000 mg per patient (interquartile range 600–1500 mg). The median Hb increase was comparable in patients receiving FCM alone (1.4 g/dl [0.2–2.3 g/dl; N = 233]) or FCM + ESA (1.6 g/dl [0.7–2.4 g/dl; N = 46]). Patients with baseline Hb up to 11.0 g/dl and serum ferritin up to 500 ng/ml benefited from FCM treatment (stable Hb ?11.0 g/dl). Also patients with ferritin >500 ng/ml but low transferrin saturation benefited from FCM treatment. FCM was well tolerated, 2.3% of patients reported putative drug-related adverse events. Conclusions The substantial Hb increase and stabilisation at 11–12 g/dl in FCM-treated patients suggest a role for i.v. iron alone in anaemia correction in cancer patients. PMID:23071262

Steinmetz, T.; Tschechne, B.; Harlin, O.; Klement, B.; Franzem, M.; Wamhoff, J.; Tesch, H.; Rohrberg, R.; Marschner, N.

2013-01-01

384

[Effectiveness of arsenite adsorption by ferric and alum water treatment residuals with different grain sizes].  

PubMed

Effectiveness of arsenite adsorption by ferric and alum water treatment residuals (FARs) with different grain sizes was studied. The results indicated that the content of active Fe and Al, the specific surface area and pore volume in FARs with different grain sizes were in the range of 523.72-1 861.72 mmol x kg(-1), 28.15-265.59 m2 x g(-1) and 0.03-0.09 cm3 x g(-1), respectively. The contents of organic matter, fulvic acid, humic acid and humin were in the range of 46.97-91.58 mg x kg(-1), 0.02-32.27 mg x kg(-1), 22.27-34.09 mg x kg(-1) and 10.76-34.22 mg x kg(-1), respectively. Results of SEM and XRD analysis further demonstrated that FARs with different grain sizes were amorphousness. Batch experiments suggested that both the pseudo-first-order and pseudo-second-order equations could well describe the kinetics adsorption processes of arsenite by FARs. Moreover, the contents of arsenite absorbed by FARs increased with the increase of arsenite concentrations. The theoretical saturated adsorption capacities calculated from Langmuir isotherm model were in the range of 6.72-21.79 mg x g(-1). Interestingly, pH showed little effect on the arsenite adsorption capability of FARs. The capability of FARs had a close relationship with their physicochemical properties. Correlation analysis showed that the active Fe and Al contents and pore volume had major effects on the arsenite adsorption capability of FARs. PMID:24028010

Lin, Lu; Xu, Jia-Rui; Wu, Hao; Wang, Chang-Hui; Pei, Yuan-Sheng

2013-07-01

385

The Porphyromonas gingivalis Ferric Uptake Regulator Orthologue Binds Hemin and Regulates Hemin-Responsive Biofilm Development  

PubMed Central

Porphyromonas gingivalis is a Gram-negative pathogen associated with the biofilm-mediated disease chronic periodontitis. P. gingivalis biofilm formation is dependent on environmental heme for which P. gingivalis has an obligate requirement as it is unable to synthesize protoporphyrin IX de novo, hence P. gingivalis transports iron and heme liberated from the human host. Homeostasis of a variety of transition metal ions is often mediated in Gram-negative bacteria at the transcriptional level by members of the Ferric Uptake Regulator (Fur) superfamily. P. gingivalis has a single predicted Fur superfamily orthologue which we have designated Har (heme associated regulator). Recombinant Har formed dimers in the presence of Zn2+ and bound one hemin molecule per monomer with high affinity (Kd of 0.23 µM). The binding of hemin resulted in conformational changes of Zn(II)Har and residue 97Cys was involved in hemin binding as part of a predicted -97C-98P-99L- hemin binding motif. The expression of 35 genes was down-regulated and 9 up-regulated in a Har mutant (ECR455) relative to wild-type. Twenty six of the down-regulated genes were previously found to be up-regulated in P. gingivalis grown as a biofilm and 11 were up-regulated under hemin limitation. A truncated Zn(II)Har bound the promoter region of dnaA (PGN_0001), one of the up-regulated genes in the ECR455 mutant. This binding decreased as hemin concentration increased which was consistent with gene expression being regulated by hemin availability. ECR455 formed significantly less biofilm than the wild-type and unlike wild-type biofilm formation was independent of hemin availability. P. gingivalis possesses a hemin-binding Fur orthologue that regulates hemin-dependent biofilm formation. PMID:25375181

Seers, Christine A.; Mitchell, Helen L.; Catmull, Deanne V.; Glew, Michelle D.; Heath, Jacqueline E.; Tan, Yan; Khan, Hasnah S. G.; Reynolds, Eric C.

2014-01-01

386

Optimizing iron delivery in the management of anemia: patient considerations and the role of ferric carboxymaltose  

PubMed Central

With the challenge of optimizing iron delivery, new intravenous (iv) iron–carbohydrate complexes have been developed in the last few years. A good example of these new compounds is ferric carboxymaltose (FCM), which has recently been approved by the US Food and Drug Administration for the treatment of iron deficiency anemia in adult patients who are intolerant to oral iron or present an unsatisfactory response to oral iron, and in adult patients with non-dialysis-dependent chronic kidney disease (NDD-CKD). FCM is a robust and stable complex similar to ferritin, which minimizes the release of labile iron during administration, allowing higher doses to be administered in a single application and with a favorable cost-effective rate. Cumulative information from randomized, controlled, multicenter trials on a diverse range of indications, including patients with chronic heart failure, postpartum anemia/abnormal uterine bleeding, inflammatory bowel disease, NDD-CKD, and those undergoing hemodialysis, supports the efficacy of FCM for iron replacement in patients with iron deficiency and iron-deficiency anemia. Furthermore, as FCM is a dextran-free iron–carbohydrate complex (which has a very low risk for hypersensitivity reactions) with a small proportion of the reported adverse effects in a large number of subjects who received FCM, it may be considered a safe drug. Therefore, FCM appears as an interesting option to apply high doses of iron as a single infusion in a few minutes in order to obtain the quick replacement of iron stores. The present review on FCM summarizes diverse aspects such as pharmacology characteristics and analyzes trials on the efficacy/safety of FCM versus oral iron and different iv iron compounds in multiple clinical scenarios. Additionally, the information on cost effectiveness and data on change in quality of life are also discussed. PMID:25525337

Toblli, Jorge Eduardo; Angerosa, Margarita

2014-01-01

387

Iron-reducing bacteria accumulate ferric oxyhydroxide nanoparticle aggregates that may support planktonic growth  

SciTech Connect

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. Further, 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 2- and 3- dimensional cryogenic transmission electron microscopy (cryo-TEM) and scanning transmission X-ray microscopy (STXM). Most cells had their outer membranes decorated with up to 150 nm diameter aggregates composed of a few 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.

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.

2013-02-04

388

Growth, spectroscopic and physicochemical properties of bis mercury ferric chloride tetra thiocyanate: a nonlinear optical crystal.  

PubMed

Single crystal of bis mercury ferric chloride tetra thiocyanate [Hg2FeCl3(SCN)4; (MFCTC)] was grown from ethanol-water (3:1) mixed solvent using slow evaporation solvent technique (SEST) for the first time. The cell parameters of the grown crystal were confirmed by single crystal XRD. The coordination of transition metal ions with the SCN ligand is well-identified using FT-IR spectral analysis. The chemical composition of MFCTC was confirmed using CHNS elemental test. The ESR spectral profile of MFCTC was recorded from 298 K to 110K, which strongly suggests the incorporation of Fe(3+) ion and its environment with respect to SCN ligand. The HPLC chromatogram of MFCTC highlights the purity of the compound. The UV-Vis-NIR studies revealed the ultra violet cut-off wavelength of MFCTC in ethanol as 338 nm. The dielectric constant and dielectric loss of the sample were studied as a function of frequency and temperature. The TGA-DTA and DSC thermal analysis show that the sample is thermally stable up to 234.31 °C, which is comparatively far better than the thermal stability of Hg3CdCl2(SCN)6; (171.3 °C) and other metal-organic coordination complex crystals such as CdHg(SCN)4 (198.5 °C), Hg(N2H4CS)4Mn(SCN)4 (199.06 °C) and Hg(N2H4CS)4Zn(SCN)4 (185 °C). The SHG conversion efficiency of MFCTC is found to be higher than KDP. PMID:23501934

Ramesh, V; Shihabuddeen Syed, A; Jagannathan, K; Rajarajan, K

2013-05-01

389

Analysis of lapine cartilage matrix after radiosynovectomy with holmium-166 ferric hydroxide macroaggregate  

PubMed Central

Objective: To study the short and long term effects of radiosynovectomy on articular cartilage in growing and mature rabbits. Methods: The articular cartilage of the distal femurs of rabbits was examined four days, two months, and one year after radiosynovectomy with holmium-166 ferric hydroxide macroaggregate ([166Ho]FHMA). Arthritic changes were evaluated from histological sections by conventional and polarised light microscopy, and glycosaminoglycan measurements using safranin O staining, digital densitometry, and uronic acid determination. Proteoglycan synthesis was studied by metabolic [35]sulphate labelling followed by autoradiography, and electrophoretic analysis of extracted proteoglycans. Northern analyses were performed to determine the mRNA levels of type II collagen, aggrecan, and Sox9 in cartilage samples. Results: Radiosynovectomy had no major effect on the histological appearance of articular cartilage in mature rabbits, whereas more fibrillation was seen in [166Ho]FHMA radiosynovectomised knee joints of growing rabbits two months after treatment, but not after one year. Radiosynovectomy did not cause changes in the glycosaminoglycan content of cartilage or in the synthesis or chemical structure of proteoglycans. No radiosynovectomy related changes were seen in the mRNA levels of type II collagen, whereas a transient down regulation of aggrecan and Sox9 mRNA levels was seen in young rabbits two months after [166Ho]FHMA radiosynovectomy. Conclusions: [166Ho]FHMA radiosynovectomy caused no obvious chondrocyte damage or osteoarthritic changes in mature rabbits, but in growing rabbits some transient radiation induced effects were seen—for example, mild cartilage fibrillation and down regulation of cartilage-specific genes. PMID:12480668

Makela, O; Lammi, M; Uusitalo, H; Hyttinen, M; Vuorio, E; Helminen, H; Tulamo, R

2003-01-01

390

Experience with intravenous ferric carboxymaltose in patients with iron deficiency anemia.  

PubMed

Erythropoiesis may be limited by absolute or functional iron deficiency or when chronic inflammatory conditions lead to iron sequestration. Intravenous iron may be indicated when oral iron cannot address the deficiency. Ferric carboxymaltose (FCM) is a nondextran iron preparation recently approved in the United States for intravenous treatment of iron deficiency anemia (IDA) in adult patients with intolerance or unsatisfactory response to oral iron or with nondialysis-dependent chronic kidney disease. The full dose is two administrations of up to 750 mg separated by at least 7 days (up to 1500 mg total). FCM can be injected in 7-8 min or diluted in saline for slower infusion. The efficacy and safety of this dose was established in two prospective trials that randomized over 3500 subjects, 1775 of whom received FCM. One trial showed similar efficacy of FCM to an approved intravenous iron regimen (1000 mg of iron sucrose) in 2500 subjects with chronic kidney disease and additional cardiovascular risk factors. The other trial showed superior efficacy of FCM to oral iron in subjects with IDA due to various etiologies (e.g. gastrointestinal or uterine bleeding). In these trials, there was no significant difference between FCM and comparator with respect to an independently adjudicated composite safety endpoint, including death, myocardial infarction, or stroke. A database of 5799 subjects exposed to FCM provided a safety profile acceptable for regulatory approval. Mechanistic studies demonstrated that the transient, asymptomatic reduction in serum phosphate observed following FCM administration results from induction of fibroblast growth factor 23, which in turn induces renal phosphate excretion. An elevated hepcidin level may identify patients with IDA who will not respond to oral iron but will respond to FCM. The ability to administer FCM in two rapid injections or infusions will likely be viewed favorably by patients and healthcare providers. PMID:24688754

Bregman, David B; Goodnough, Lawrence T

2014-04-01

391

Experience with intravenous ferric carboxymaltose in patients with iron deficiency anemia  

PubMed Central

Erythropoiesis may be limited by absolute or functional iron deficiency or when chronic inflammatory conditions lead to iron sequestration. Intravenous iron may be indicated when oral iron cannot address the deficiency. Ferric carboxymaltose (FCM) is a nondextran iron preparation recently approved in the United States for intravenous treatment of iron deficiency anemia (IDA) in adult patients with intolerance or unsatisfactory response to oral iron or with nondialysis-dependent chronic kidney disease. The full dose is two administrations of up to 750 mg separated by at least 7 days (up to 1500 mg total). FCM can be injected in 7–8 min or diluted in saline for slower infusion. The efficacy and safety of this dose was established in two prospective trials that randomized over 3500 subjects, 1775 of whom received FCM. One trial showed similar efficacy of FCM to an approved intravenous iron regimen (1000 mg of iron sucrose) in 2500 subjects with chronic kidney disease and additional cardiovascular risk factors. The other trial showed superior efficacy of FCM to oral iron in subjects with IDA due to various etiologies (e.g. gastrointestinal or uterine bleeding). In these trials, there was no significant difference between FCM and comparator with respect to an independently adjudicated composite safety endpoint, including death, myocardial infarction, or stroke. A database of 5799 subjects exposed to FCM provided a safety profile acceptable for regulatory approval. Mechanistic studies demonstrated that the transient, asymptomatic reduction in serum phosphate observed following FCM administration results from induction of fibroblast growth factor 23, which in turn induces renal phosphate excretion. An elevated hepcidin level may identify patients with IDA who will not respond to oral iron but will respond to FCM. The ability to administer FCM in two rapid injections or infusions will likely be viewed favorably by patients and healthcare providers. PMID:24688754

Goodnough, Lawrence T.

2014-01-01

392

Safety and tolerability of intravenous ferric carboxymaltose in patients with iron deficiency anemia.  

PubMed

There is limited safety information about ferric carboxymaltose (FCM), a new intravenous iron preparation. This randomized, crossover study compared the safety and tolerability of double-blinded intravenous doses of FCM or placebo in patients with iron deficiency anemia. Subjects (559) with iron deficiency anemia received a dose of either FCM (15 mg/kg, maximum 1000 mg) over 15 minutes or placebo on day 0. On day 7, subjects received the other agent. Safety evaluations were performed on days 7 and 14. The primary endpoint was the incidence of treatment-emergent adverse events during each 7-day study period. During the first 24 hours and during the 7-day treatment period, at least one treatment-emergent adverse event was experienced by 15.0% and 29.3% of subjects after FCM and 11.4% and 19.7% after placebo, respectively. Most were classified as Grade 1 or 2. Six subjects had Grade 3 treatment-emergent adverse events after FCM and 9 subjects after placebo. One subject had a Grade 4, and 1 subject had a Grade 5 treatment-emergent adverse event, but neither was considered study drug-related. During the first 24 hours of the treatment period, drug-related adverse events were reported in 9.3% of subjects receiving FCM and 4.8% receiving placebo. Of drug-related Grade 3 events, 4 subjects received FCM and 5 subjects received placebo. Administration of FCM (15 mg/kg, maximum of 1000 mg) over 15 minutes was well tolerated and associated with minimal risk of adverse reactions in patients with iron deficiency anemia. PMID:19888949

Bailie, George R; Mason, Nancy A; Valaoras, Thomas G

2010-01-01

393

Optimizing iron delivery in the management of anemia: patient considerations and the role of ferric carboxymaltose.  

PubMed

With the challenge of optimizing iron delivery, new intravenous (iv) iron-carbohydrate complexes have been developed in the last few years. A good example of these new compounds is ferric carboxymaltose (FCM), which has recently been approved by the US Food and Drug Administration for the treatment of iron deficiency anemia in adult patients who are intolerant to oral iron or present an unsatisfactory response to oral iron, and in adult patients with non-dialysis-dependent chronic kidney disease (NDD-CKD). FCM is a robust and stable complex similar to ferritin, which minimizes the release of labile iron during administration, allowing higher doses to be administered in a single application and with a favorable cost-effective rate. Cumulative information from randomized, controlled, multicenter trials on a diverse range of indications, including patients with chronic heart failure, postpartum anemia/abnormal uterine bleeding, inflammatory bowel disease, NDD-CKD, and those undergoing hemodialysis, supports the efficacy of FCM for iron replacement in patients with iron deficiency and iron-deficiency anemia. Furthermore, as FCM is a dextran-free iron-carbohydrate complex (which has a very low risk for hypersensitivity reactions) with a small proportion of the reported adverse effects in a large number of subjects who received FCM, it may be considered a safe drug. Therefore, FCM appears as an interesting option to apply high doses of iron as a single infusion in a few minutes in order to obtain the quick replacement of iron stores. The present review on FCM summarizes diverse aspects such as pharmacology characteristics and analyzes trials on the efficacy/safety of FCM versus oral iron and different iv iron compounds in multiple clinical scenarios. Additionally, the information on cost effectiveness and data on change in quality of life are also discussed. PMID:25525337

Toblli, Jorge Eduardo; Angerosa, Margarita

2014-01-01

394

Growth, spectroscopic and physicochemical properties of bis mercury ferric chloride tetra thiocyanate: A nonlinear optical crystal  

NASA Astrophysics Data System (ADS)

Single crystal of bis mercury ferric chloride tetra thiocyanate [Hg2FeCl3(SCN)4; (MFCTC)] was grown from ethanol-water (3:1) mixed solvent using slow evaporation solvent technique (SEST) for the first time. The cell parameters of the grown crystal were confirmed by single crystal XRD. The coordination of transition metal ions with the SCN ligand is well-identified using FT-IR spectral analysis. The chemical composition of MFCTC was confirmed using CHNS elemental test. The ESR spectral profile of MFCTC was recorded from 298 K to 110 K, which strongly suggests the incorporation of Fe3+ ion and its environment with respect to SCN ligand. The HPLC chromatogram of MFCTC highlights the purity of the compound. The UV-Vis-NIR studies revealed the ultra violet cut-off wavelength of MFCTC in ethanol as 338 nm. The dielectric constant and dielectric loss of the sample were studied as a function of frequency and temperature. The TGA-DTA and DSC thermal analysis show that the sample is thermally stable up to 234.31 °C, which is comparatively far better than the thermal stability of Hg3CdCl2(SCN)6; (171.3 °C) and other metal-organic coordination complex crystals such as CdHg(SCN)4 (198.5 °C), Hg(N2H4CS)4Mn(SCN)4 (199.06 °C) and Hg(N2H4CS)4Zn(SCN)4 (185 °C). The SHG conversion efficiency of MFCTC is found to be higher than KDP.

Ramesh, V.; Shihabuddeen Syed, A.; Jagannathan, K.; Rajarajan, K.

2013-05-01

395

Effect of ferric oxyhydroxide grain coatings on the transport of bacteriophage PRD1 and Cryptosporidium parvum oocysts in saturated porous media  

USGS Publications Warehouse

To test the effect of geochemical heterogeneity on microorganism transport in saturated porous media, we measured the removal of two microorganisms, the bacteriophage PRD1 and oocysts of the protozoan parasite Cryptosporidium parvum, in flow-through columns of quartz sand coated by different amounts of a ferric oxyhydroxide. The experiments were conducted over ranges of ferric oxyhydroxide coating fraction of ?? = 0-0.12 for PRD1 and from ?? = 0-0.32 for the oocysts at pH 5.6-5.8 and 10-4 M ionic strength. To determine the effect of pH on the transport of the oocysts, experiments were also conducted over a pH range of 5.7-10.0 at a coating fraction of ?? = 0.04. Collision (attachment) efficiencies increased as the fraction of ferric oxyhydroxide coated quartz sand increased, from ?? = 0.0071 to 0.13 over ?? = 0-0.12 for PRD1 and from ?? = 0.059 to 0.75 over ?? = 0-0.32 for the oocysts. Increasing the pH from 5.7 to 10.0 resulted in a decrease in the oocyst collision efficiency as the pH exceeded the expected point of zero charge of the ferric oxyhydroxide coatings. The collision efficiencies correlated very well with the fraction of quartz sand coated by the ferric oxyhydroxide for PRD1 but not as well for the oocysts. ?? 2005 American Chemical Society.

Abudalo, R.A.; Bogatsu, Y.G.; Ryan, J.N.; Harvey, R.W.; Metge, D.W.; Elimelech, M.

2005-01-01

396

Assessment of mapping exposed ferrous and ferric iron compounds using Skylab-EREP data. [Pisgah Crater, California  

NASA Technical Reports Server (NTRS)

The author has identified the following significant results. The S190B color photography is as useful as LANDSAT data for the mapping of color differences in the rocks and soils of the terrain. An S192 ratio of 0.79 - 0.89 and 0.93 - 1.05 micron bands produced an apparently successful delineation of ferrous, ferric, and other materials, in agreement with theory and ratio code studies. From an analysis of S191 data, basalt and dacite were separated on the basis of differences in spectral emissivity in the 8.3 - 12 micron region.

Vincent, R. (principal investigator); Wagner, H.; Pillars, W.; Bennett, C.

1976-01-01

397

Potentially life-threatening phosphate diabetes induced by ferric carboxymaltose injection: a case report and review of the literature.  

PubMed

We report the case of a 45-year-old female patient who developed phosphate diabetes after administration of ferric carboxymaltose. Ten days after the second dose, she complained of intense fatigue and blood analysis showed a phosphate plasma level of 0.93?mg/dL with phosphate excretion rate of 23%. She received phosphate supplementation which resulted in phosphate clearance improvement which persisted for two months. We reviewed other cases described in the literature and would draw attention to this rare but potentially life-threatening side effect. PMID:25478250

Vandemergel, Xavier; Vandergheynst, Frédéric

2014-01-01

398

Dose and time-dependent ?-synuclein aggregation induced by ferric iron in SK-N-SH cells  

Microsoft Academic Search

Objective  Intracellular formation of Lewy body (LB) is one of the hallmarks of Parkinson’s disease. The main component of LB is aggregated\\u000a ?-synuclein, present in the substantia nigra where iron accumulation also occurs. The present study was aimed to study the\\u000a relationship between iron and ?-synuclein aggregation.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  SK-N-SH cells were treated with different concentrations of ferric iron for 24 h or

Wen-Jing Li; Hong Jiang; Ning Song; Jun-Xia Xie

2010-01-01

399

Ibuprofen Impairs Allosterically Peroxynitrite Isomerization by Ferric Human Serum Heme-Albumin*  

PubMed Central

Human serum albumin (HSA) participates in heme scavenging; in turn, heme endows HSA with myoglobin-like reactivity and spectroscopic properties. Here, the allosteric effect of ibuprofen on peroxynitrite isomerization to NO3? catalyzed by ferric human serum heme-albumin (HSA-heme-Fe(III)) is reported. Data were obtained at 22.0 °C. HSA-heme-Fe(III) catalyzes peroxynitrite isomerization in the absence and presence of CO2; the values of the second order catalytic rate constant (kon) are 4.1 × 105 and 4.5 × 105 m?1 s?1, respectively. Moreover, HSA-heme-Fe(III) prevents peroxynitrite-mediated nitration of free added l-tyrosine. The pH dependence of kon (pKa = 6.9) suggests that peroxynitrous acid reacts preferentially with the heme-Fe(III) atom, in the absence and presence of CO2. The HSA-heme-Fe(III)-catalyzed isomerization of peroxynitrite has been ascribed to the reactive pentacoordinated heme-Fe(III) atom. In the absence and presence of CO2, ibuprofen impairs dose-dependently peroxynitrite isomerization by HSA-heme-Fe(III) and facilitates the nitration of free added l-tyrosine; the value of the dissociation equilibrium constant for ibuprofen binding to HSA-heme-Fe(III) (L) ranges between 7.7 × 10?4 and 9.7 × 10?4 m. Under conditions where [ibuprofen] is ?L, the kinetics of HSA-heme-Fe(III)-catalyzed isomerization of peroxynitrite is superimposable to that obtained in the absence of HSA-heme-Fe(III) or in the presence of non-catalytic HSA-heme-Fe(III)-cyanide complex and HSA. Ibuprofen binding impairs allosterically peroxynitrite isomerization by HSA-heme-Fe(III), inducing the hexacoordination of the heme-Fe(III) atom. These results represent the first evidence for peroxynitrite isomerization by HSA-heme-Fe(III), highlighting the allosteric modulation of HSA-heme-Fe(III) reactivity by heterotropic interaction(s), and outlining the role of drugs in modulating HSA functions. The present results could be relevant for the drug-dependent protective role of HSA-heme-Fe(III) in vivo. PMID:19734142

Ascenzi, Paolo; di Masi, Alessandra; Coletta, Massimo; Ciaccio, Chiara; Fanali, Gabriella; Nicoletti, Francesco P.; Smulevich, Giulietta; Fasano, Mauro

2009-01-01

400

The new generation of intravenous iron: chemistry, pharmacology, and toxicology of ferric carboxymaltose.  

PubMed

An ideal preparation for intravenous iron replacement therapy should balance effectiveness and safety. Compounds that release iron rapidly tend to cause toxicity, while large molecules can induce antibody formation and cause anaphylactic reactions. There is therefore a need for an intravenous iron preparation that delivers appropriate amounts of iron in a readily available form but with minimal side effects and thus with an excellent safety profile. In this paper, a review is given on the chemistry, pharmacology, and toxicology of ferric carboxymaltose (FCM, Ferinject), a stable and robust complex formulated as a colloidal solution with a physiological pH. The complex is gradually taken up mainly from the hepatic reticulo-endothelial system (RES), followed by effective delivery of iron to the endogeneous transport system for the haem synthesis in new erythrocytes, as shown in studies on the pharmacodynamics and pharmacokinetics with radio-labelled FCM. Studies with radio-labelled FCM also demonstrated a barrier function of the placenta and a low transfer of iron into the milk of lactating rats. Safety pharmacology studies indicated a favourable profile with regard to cardiovascular, central nervous, respiratory, and renal toxicity. A high maximum non-lethal dose was demonstrated in the single-dose toxicity studies. Furthermore, based on the No-Observed-Adverse-Effect-Levels (NOAELs) found in repeated-dose toxicity studies and on the cumulative doses administered, FCM has good safety margins. Reproductive and developmental toxicity studies did not reveal any direct or indirect harmful effects. No genotoxic potential was found in in vitro or in vivo studies. Moreover, antigenicity studies showed no cross-reactivity of FMC with anti-dextran antibodies and also suggested that FCM does not possess sensitizing potential. Lastly, no evidence of irritation was found in local tolerance studies with FCM. This excellent toxicity profile and the high effectiveness of FCM allow the administration of high doses as a single infusion or bolus injection, which will enhance the cost-effectiveness and convenience of iron replacement therapy. In conclusion, FCM has many of the characteristics of an ideal intravenous iron preparation. PMID:20648926

Funk, Felix; Ryle, Peter; Canclini, Camillo; Neiser, Susann; Geisser, Peter

2010-01-01

401

Functional characterization of the dimerization domain of the ferric uptake regulator (Fur) of Pseudomonas aeruginosa.  

PubMed

The functional properties of the recombinant C-terminal dimerization domain of the Pseudomonas aeruginosa Fur (ferric uptake regulator) protein expressed in and purified from Escherichia coli have been evaluated. Sedimentation velocity measurements demonstrate that this domain is dimeric, and the UV CD spectrum is consistent with a secondary structure similar to that observed for the corresponding region of the crystallographically characterized wild-type protein. The thermal stability of the domain as determined by CD spectroscopy decreases significantly as pH is increased and increases significantly as metal ions are added. Potentiometric titrations (pH 6.5) establish that the domain possesses a high-affinity and a low-affinity binding site for metal ions. The high-affinity (sensory) binding site demonstrates association constants (K(A)) of 10(+/-7)x10(6), 5.7(+/-3)x10(6), 2.0(+/-2)x10(6) and 2.0(+/-3)x10(4) M(-1) for Ni2+, Zn2+, Co2+ and Mn2+ respectively, while the low-affinity (structural) site exhibits association constants of 1.3(+/-2)x10(6), 3.2(+/-2)x10(4), 1.76(+/-1)x10(5) and 1.5(+/-2)x10(3) M(-1) respectively for the same metal ions (pH 6.5, 300 mM NaCl, 25 degrees C). The stability of metal ion binding to the sensory site follows the Irving-Williams order, while metal ion binding to the partial sensory site present in the domain does not. Fluorescence experiments indicate that the quenching resulting from binding of Co2+ is reversed by subsequent titration with Zn2+. We conclude that the domain is a reasonable model for many properties of the full-length protein and is amenable to some analyses that the limited solubility of the full-length protein prevents. PMID:16928194

Bai, Erdeni; Rosell, Federico I; Lige, Bao; Mauk, Marcia R; Lelj-Garolla, Barbara; Moore, Geoffrey R; Mauk, A Grant

2006-12-15

402

The high temperature thermoelectric performances of Zr0.5Hf0.5Ni0.8Pd0.2Sn0.99Sb0.01 alloy with nanophase inclusions  

NASA Astrophysics Data System (ADS)

The Zr0.5Hf0.5Ni0.8Pd0.2Sn0.99Sb0.01/ZrO2 nanocomposites have been prepared by spark plasma sintering technique. The thermoelectric properties were measured in the temperature range of 300-900 K. Thermal conductivity for the nanocomposites is considerably reduced, because the nanophase scatters the thermal phonons which transport most of the heat in the ZrNiSn-based alloy. Seebeck coefficient for the nanocomposites is enhanced due to the potential barrier scattering. The dimensionless figure of merit ZT is improved, with ZT~0.75 at 800 K for the samples containing 9 vol % ZrO2 nanoinclusions. The results obtained suggest that considerable improvements in the thermoelectric figure of merit may be obtainable by inducing appropriate nanoinclusions into the matrix.

Chen, L. D.; Huang, X. Y.; Zhou, M.; Shi, X.; Zhang, W. B.

2006-03-01

403

The Reduction of Aqueous Metal Species on the Surfaces of Fe(II)-Containing Oxides: The Role of Surface Passivation  

USGS Publications Warehouse

The reduction of aqueous transition metal species at the surfaces of Fe(II)- containing oxides has important ramifications in predicting the transport behavior in ground water aquifers. Experimental studies using mineral suspensions and electrodes demonstrate that structural Fe(II) heterogeneously reduces aqueous ferric, cupric, vanadate and chromate ions on magnetite and ilmenite surfaces. The rates of metal reduction on natural oxides is strongly dependent on the extent of surface passivation and redox conditions in the weathering environment. Synchrotron studies show that surface oxidation of Fe(II)-containing oxide minerals decreases their capacity for Cr(VI) reduction at hazardous waste disposal sites.

White, A.F.; Peterson, M.L.

1998-01-01

404

First-principles study of spin transition and seismic properties of ferric iron-bearing post-perovskite with oxygen vacancy  

NASA Astrophysics Data System (ADS)

The spin states, elastic properties and seismic velocities of ferric iron-bearing post-perovskite MgSiO3 (pPv) with single oxygen vacancy [Mg8(Si6,Fe2)O23 and Mg16(Si14,Fe2)O47] were calculated by first principles based on density functional theory. The effects of ferric iron and oxygen vacancy on seismic waves were studied for the host pPv subjected to a hydrostatic pressure. Calculations revealed a new spin transition from intermediate-spin to low-spin states with increasing pressure. As a result, the volume was reduced and the elastic constants were modified, producing a clear decrease in the seismic velocities of both compressive wave and shear wave due to the reduction of bulk modulus and shear modulus. The ferric iron and oxygen vacancy also had a minor effect on wave anisotropy.

Gao, Benzhou; He, Kaihua; Chen, Qili; Wang, Xicheng; Wang, Qingbo; Wan, Miao; Ji, Guangfu

2014-09-01

405

Influence of the addition of sulphate and ferric ions in a methanogenic anaerobic packed-bed reactor treating gasoline-contaminated water.  

PubMed

Benzene, toluene and xylene (BTX) are relatively soluble aromatic compounds of gasoline. Gasoline storage tank leakages generally lead to an extensive contamination of groundwater. In the natural environment for instance, these compounds might be biodegraded under a variety of reducing potentials. The objective of this work was to examine the influence of the addition of sulphate and Fe(OH)3 in a methanogenic horizontal-flow anaerobic immobilized-biomass reactor treating gasoline-contaminated water. Three different conditions were evaluated: methanogenic, sulphidogenic and sulphidogenic with the addition of ferric ions. Methanogenic condition showed the higher BTX degradation rates and the addition of sulphate negatively affected BTX removal rates with the production of H2S. However, the addition of ferric ions resulted in the precipitation of sulphur, improving BTX degradation by the consortium. Metanosphaera sp., Methanosarcina barkeri and Methanosaeta concilii were identified in the consortium by means of 16S and directly related to the addition of ferric ions. PMID:16939094

Fernandes, B S; Chinalia, F A; Sarti, A; Silva, A J; Foresti, E; Zaiat, M

2006-01-01

406

Iron isotope fractionation during photo-oxidation of aqueous ferrous iron  

NASA Astrophysics Data System (ADS)

The classic interpretation of banded iron formations (BIFs) presumes the presence of dissolved O2 in the surface ocean to oxidize ferrous Fe. However, at least two alternative oxidation mechanisms are possible: UV photo-oxidation; and the activity of anaerobic Fe(II)-oxidizing photosynthetic bacteria. We are investigating Fe isotope fractionation as a means of differentiating amongst these mechanisms. Photo-oxidation has been examined at pH ~ 3 and 41°C in the absence of ligands other than H2O, OH-, and Cl- using UVA (316-400 nm) and UVC (200-280 nm) light sources. In these experiments, ferrous Fe was oxidized and precipitated as ferric oxyhydroxide. We find that isotopically heavy Fe was preferentially removed from solution. The fractionation factor (?) for the overall reaction is ~ 1.0025. This value is comparable to the ? between Fe2+ and Fe3+ hexaquo complexes, but larger than the effect seen during the overall process of ferrous Fe oxidation and precipitation at near-neutral pH. The magnitude of isotope fractionation is likely to change at higher pH for two reasons. First, ferric oxyhydroxide precipitation, which may impart a kinetic isotope effect, is faster at higher pH. Second, the major UV-absorbing ferrous species in the ocean is the ferrous hydroxide ion [Fe(OH)+], the concentration of which is strongly pH dependent. Photo-oxidation experiments at realistic seawater pH are under current investigation.

Staton, S.; Amskold, L.; Gordon, G.; Anbar, A.; Konhauser, K.

2006-05-01

407

The effects of metallic catalysts on light crude oil oxidation in limestone medium  

Microsoft Academic Search

In this study, 28 experiments were performed to study the effects of metallic additives on light crude oil oxidation in limestone medium. Karaku? and Beykan crude oils from Turkish oil fields were used. The metallic additives were ferric chloride (FeCl3), copper chloride (CuCl) and magnesium chloride (MgCl2·6H2O). The mixture of aqueous solutions of three metallic salts with limestone and the

Demet Ēelebio?lu; Suat Ba?ci

2002-01-01

408

Preparation of activated carbons from Iris tectorum employing ferric nitrate as dopant for removal of tetracycline from aqueous solutions.  

PubMed

Ferric nitrate was employed to modify activated carbon prepared from Iris tectorum during H?PO? activation and ability of prepared activated carbon for removal of tetracycline (TC) was investigated. The properties of the activated carbon samples with or without ferric nitrate, ITAC-Fe and ITAC, were measured by scanning electron microscopy (SEM), N? adsorption/desorption isotherms, Fourier transform infrared spectroscopy (FTIR) and Boehm's titration. The results showed that mixing with iron increased the BET surface area, total pore volume and the adsorption capacity as compared to the original carbon. FTIR and Boehm's titration suggested that ITAC-Fe was characteristic of more acidic functional groups than ITAC. Adsorption of TC on both samples exhibited a strong pH-dependent behavior and adsorption capacity reduced rapidly with the increasing solution pH. The adsorption kinetics agreed well with the pseudo-second-order model and the adsorption isotherms data were well described by Langmuir model with the maximum adsorption capacity of 625.022 mg/g for ITAC and 769.231 mg/g for ITAC-Fe. The present work suggested that ITAC-Fe could be used to remove tetracycline effectively from aqueous solutions. PMID:24021870

Li, Gang; Zhang, Dongsheng; Wang, Man; Huang, Ji; Huang, Lihui

2013-12-01

409

Properties and coagulation performance of coagulant poly-aluminum-ferric-silicate-chloride in water and wastewater treatment.  

PubMed

An efficient inorganic polymer coagulant, poly-aluminum-ferric-silicate-chloride (PAFSC), was developed using two approaches: (i) hydroxylation of the mixture of AlCl3, FeCl3 and fresh polysilicic acid in different Al/Fe/Si molar ratios to obtain PAFSCc and (ii) hydroxylated poly-aluminum-iron-chloride (PAFC) combined with aged polysilicic acid in different Al/Fe/Si ratios to produce PAFSCm. The properties of PAFSC in comparison with polyaluminum silicate chloride (PASC) and polyferric silicate chloride (PAFC) were characterized by various experimental methods. The effect of Al/Fe/Si molar ratio on the hydrolysis-polymerization process of Al (III) and Fe (III) in PAFSC solutions was examined by pH titration, and the effect of Al/Fe/Si molar ratio on electrokinetic mobility of PAFSC was studied by Zeta potential measurement. The laboratory experiments were performed to evaluate the PAFSC in comparison with polyaluminum chloride (PAC) for the coagulation of synthetic water samples, actual surface water and wastewater. The results show that interactions exist among aluminum species, ferric species and polysilicic acid, and the Al/Fe/Si molar ratio affects the Zeta potential of the hydrolyzate and the coagulating performance. PAFSC achieved a better water treatment result than PAC. At the same basicity (B) value and Al/Fe/Si ratio, PAFSCc has better coagulation performance than PAFSCm. PAFSC is a new type and high efficiency composite inorganic polymer coagulant. PMID:16854802

Gao, Bao-yu; Yue, Qin-yan; Wang, Bing-jian

2006-01-01

410

Ferric complexes of 3-hydroxy-4-pyridinones characterized by density functional theory and Raman and UV-vis spectroscopies.  

PubMed

Deferiprone and other 3-hydroxy-4-pyridinones are used in metal chelation therapy of iron overload. To investigate the structure and stability of these compounds in the natural aqueous environment, ferric complexes of deferiprone and amino acid maltol conjugates were synthesized and studied by computational and optical spectroscopic methods. The complexation caused characteristic intensity changes, a 300× overall enhancement of the Raman spectrum, and minor changes in UV-vis absorption. The spectra were interpreted on the basis of density functional theory (DFT) calculations. The CAM-B3LYP and ?B97XD functionals with CPCM solvent model were found to be the most suitable for simulations of the UV-vis spectra, whereas B3LYP, B3LYPD, B3PW91, M05-2X, M06, LC-BLYP, ?B97XD, and CAM-B3LYP functionals were all useful for simulation of the Raman scattering. Characteristic Raman band frequencies for 3-hydroxy-4-pyridinones were assigned to molecular vibrations. The computed conformer energies consistently suggest the presence of another isomer of the deferiprone-ferric complex in solution, in addition to that found previously by X-ray crystallography. However, the UV-vis and Raman spectra of the two species are similar and could not be resolved. In comparison to UV-vis, the Raman spectra and their combination with calculations appear more promising for future studies of iron sequestrating drugs and artificial metalloproteins as they are more sensitive to structural details. PMID:22468647

Šebestķk, Jaroslav; Safa?ķk, Martin; Bou?, Petr

2012-04-16

411

Oral iron absorption test in patients on CAPD: comparison of ferrous sulfate and a polysaccharide ferric complex.  

PubMed

We prospectively compared the absorption of ferrous sulfate to that of a polysaccharide ferric complex (Niferex) in 5 healthy controls and 7 stable patients on continuous ambulatory peritoneal dialysis (CAPD). All study subjects received an equivalent of 150 mg of elemental iron of either preparation, in a random fashion. After a baseline fasting serum iron level was obtained, the serum iron concentration was measured at 2 h in the control group and at 2 and 4 h in the CAPD patients. One to 2 months later, all study subjects received the alternative iron compound and were studied in an identical manner. A significant rise in serum iron was only observed in the healthy subjects after the ingestion of ferrous sulfate and not Niferex (ferrous sulfate 102 +/- (SE) 9 vs. 142 +/- 7 Mg/dl, p = 0.0005; Niferex 96 +/- (SE) 10 vs. 102 +/- 12 mg/dl; baseline vs. 2 h, respectively). The absorption of both compounds was poor in the patients on CAPD, with the 2- and 4-hour serum iron levels not significantly higher than the baseline values (ferrous sulfate 73 +/- 7 vs. 107 +/- 21 vs. 109 +/- 21 mg/dl, p = NS; Niferex 57 +/- 11 vs. 65 +/- 14 vs. 60 +/- 11 mg/dl, p = NS; baseline vs. 2 vs. 4 h, respectively). Our data suggest that the absorption of both ferrous sulfate and ferric polysaccharide complex is poor in patients on CAPD. PMID:8893143

Tinawi, M; Martin, K J; Bastani, B

1996-01-01

412

Eleven-years-long record of ferric hydroxide sedimentation in Satsuma Iwo-Jima island, Kagoshima, Japan  

NASA Astrophysics Data System (ADS)

Satsuma Iwo-Jima island is active in volcanic activity located about 40 km south of Kyushu Island, Japan. It has many hot springs, and is surrounded by patches of reddish brown and white colored seawater. Nagahama Bay, a small port located in the southern part of the island, retains reddish brown seawater and precipitates ferric hydroxide (Ninomiya and Kiyokawa, 2009). We conducted multidisciplinary study to investigate mechanisms and histories of precipitation of the sediments. From 2009 to 2011, we obtained 1.5m-long core samples in the bay that record sedimentation of mainly ferric hydroxide during the last 11~13 years since dredging in 1998. We compare their stratigraphy with (a) 11 years meteorological data and (b) volcanic activity record in that period. Stratigraphy: Thirteen short cores (<1m long) were collected from Nagahama Bay. The lower unit contains three layers of white and pink tuff beds (T1, T2 and T3) with thickness of 1~9cm. The upper unit mainly contains sand bed and reddish-brown mud. The tuff beds are mainly composed of volcanic glass. Sand bed is essentially a mixture of felsic rock fragments, volcanic glass, and ferric-rich fine materials. The reddish brown sediment between T1 and T2 has very fine orange-colored laminations (1~2mm thick/each). (a) Meteorological data: 11-years-long meteorological data of the Satsuma Iwo-Jima island suggest that heavy rainfalls (precipitation over 100mm/day) occurred in June 2000 (189mm/day), June 2001 (124.5mm/day), and June 2002 (122mm/day), and that three events of strong typhoon occurred in 2004 (maximum wind speed: 40.3m/s, 54.3m/s and 44.6m/s), 2005 (43.3m/s), and 2007 (50.2m/s). These meteorological events are reflected in, sometimes disturb, the sediment record. (b) Volcanic data: Volcanic activity has occurred from 1997 (Shinohara, 2002) to October 2004 (Japan Meteorological Agency, 2010). During that time, ash was spewed out from and deposited near the volcano. Tuffaceous beds in the sediments of Nagahama Bay record such volcanic activity, however reworking of sediments by meteorological events are found to obscure such record. Conclusions: We found two sedimentological events that play important role in forming sediments in Nagahama Bay; heavy rainfall and strong typhoon. The thick tuff beds (T1, T2 and T3) formed by reworking sediments induced by heavy rainfall. The sand bed formed by hydrodynamic mixings due to strong typhoon events in 2004. The ferric hydroxide-rich surface sediments are very loose and easily flown by hydrodynamic currents in the bay. However, once particles of the ferric hydrate precipitate at the seafloor, only strong current could move them. Neap tide may enhance their sedimentation and thus help to form strata.

Ueshiba, T.; Kiyokawa, S.; Goto, S.; Oguri, K.; Ito, T.; Ikehara, M.; Yamaguchi, K. E.; Nagata, T.; Ninomiya, T.; Ikegami, F.

2011-12-01

413

Progress in the development and use of ferrate(VI) salt as an oxidant and coagulant for water and wastewater treatment  

Microsoft Academic Search

This paper reviews the progress in preparing and using ferrate(VI) salt as an oxidant and coagulant for water and wastewater treatment. The literature revealed that due to its unique properties (viz. strong oxidizing potential and simultaneous generation of ferric coagulating species), ferrate(VI) salt can disinfect microorganisms, partially degrade and\\/or oxidise the organic and inorganic impurities, and remove suspended\\/colloidal particulate materials

Jia-Qian Jiang; Barry Lloyd

2002-01-01

414

Template synthesis of nanophase mesocarbon.  

PubMed

Templating techniques are used increasingly to create carbon materials with precisely engineered pore systems. This article presents a new templating technique that achieves simultaneous control of pore structure and molecular (crystal) structure in a single synthesis step. With the use of discotic liquid crystalline precursors, unique carbon structures can be engineered by selecting the size and geometry of the confining spaces and selecting the template material to induce edge-on or face-on orientation of the discotic precursor. Here mesophase pitch is infiltrated by capillary forces into a nanoporous glass followed by slow carbonization and NaOH etching. The resulting porous carbon material exhibits interconnected solid grains about 100 nm in size, a monodisperse pore size of 60 nm, 42% total porosity, and an abundance of edge-plane inner surfaces that reflect the favored edge-on anchoring of the mesophase precursor on glass. This new carbon form is potentially interesting for a number of important applications in which uniform large pores, active-site-rich surfaces, and easy access to interlayer spaces in nanometric grains are advantageous. PMID:14733148

Yang, Nancy Y; Jian, Kengqing; Külaots, Indrek; Crawford, Gregory P; Hurt, Robert H

2003-10-01

415

Nanophase and Composite Optical Materials  

NASA Technical Reports Server (NTRS)

This talk will focus on accomplishments, current developments, and future directions of our work on composite optical materials for microgravity science and space exploration. This research spans the order parameter from quasi-fractal structures such as sol-gels and other aggregated or porous media, to statistically random cluster media such as metal colloids, to highly ordered materials such as layered media and photonic bandgap materials. The common focus is on flexible materials that can be used to produce composite or artificial materials with superior optical properties that could not be achieved with homogeneous materials. Applications of this work to NASA exploration goals such as terraforming, biosensors, solar sails, solar cells, and vehicle health monitoring, will be discussed.

2003-01-01

416

Extraction of copper from an oxidized (lateritic) ore using bacterially catalysed reductive dissolution.  

PubMed

An oxidized lateritic ore which contained 0.8 % (by weight) copper was bioleached in pH- and temperature-controlled stirred reactors under acidic reducing conditions using pure and mixed cultures of the acidophilic chemolithotrophic bacterium Acidithiobacillus ferrooxidans. Sulfur was provided as the electron donor for the bacteria, and ferric iron present in goethite (the major ferric iron mineral present in the ore) acted as electron acceptor. Significantly more copper was leached by bacterially catalysed reductive dissolution of the laterite than in aerobic cultures or in sterile anoxic reactors, with up to 78 % of the copper present in the ore being extracted. This included copper that was leached from acid-labile minerals (chiefly copper silicates) and that which was associated with ferric iron minerals in the lateritic ore. In the anaerobic bioreactors, soluble iron in the leach liquors was present as iron (II) and copper as copper (I), but both metals were rapidly oxidized (to iron (III) and copper (II)) when the reactors were aerated. The number of bacteria added to the reactors had a critical role in dictating the rate and yield of copper solubilised from the ore. This work has provided further evidence that reductive bioprocessing, a recently described approach for extracting base metals from oxidized deposits, has the potential to greatly extend the range of metal ores that can be biomined. PMID:24687752

Nancucheo, Ivan; Grail, Barry M; Hilario, Felipe; du Plessis, Chris; Johnson, D Barrie

2014-07-01

417

Survey of ferric reductase transcription and activity in Pisum sativum accessions  

Technology Transfer Automated Retrieval System (TEKTRAN)

Iron (Fe) is an essential element for the growth of plants. While Fe is not limiting in most soils (it makes up approximately 5% of total soil minerals), Fe availability to plants in aerated, calcareous soils near neutral or basic pH can be severely limited as Fe oxidizes to form less soluble ferri...