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Sample records for polymer-assisted iron oxide

  1. Polymer-assisted aqueous deposition of metal oxide films

    DOEpatents

    Li, DeQuan; Jia, Quanxi

    2003-07-08

    An organic solvent-free process for deposition of metal oxide thin films is presented. The process includes aqueous solutions of necessary metal precursors and an aqueous solution of a water-soluble polymer. After a coating operation, the resultant coating is fired at high temperatures to yield optical quality metal oxide thin films.

  2. Nucleation and growth of epitaxial metal-oxide films based on polymer-assisted deposition.

    PubMed

    McCleskey, T M; Shi, P; Bauer, E; Highland, M J; Eastman, J A; Bi, Z X; Fuoss, P H; Baldo, P M; Ren, W; Scott, B L; Burrell, A K; Jia, Q X

    2014-04-01

    Polymer-assisted deposition (PAD) is one of the chemical solution deposition methods which have been successfully used to grow films, form coatings, and synthesize nanostructured materials. In comparison with other conventional solution-based deposition techniques, PAD differs in its use of water-soluble polymers in the solution that prevent the metal ions from unwanted chemical reactions and keep the solution stable. Furthermore, filtration to remove non-coordinated cations and anions in the PAD process ensures well controlled nucleation, which enables the growth of high quality epitaxial films with desired structural and physical properties. The precursor solution is prepared by mixing water-soluble polymer(s) with salt(s). Thermal treatment of the precursor films in a controlled environment leads to the formation of desired materials. Using BaTiO3 grown on SrTiO3 and LaMnO3 on LaAlO3 as model systems, we show the effect of filtration on the nucleation and growth of epitaxial complex metal-oxide films based on the PAD process. PMID:24158602

  3. Heavy-Ion Irradiation of Thulium(III) Oxide Targets Prepared by Polymer-Assisted Deposition

    SciTech Connect

    Garcia, Mitch A.; Ali, Mazhar N.; Chang, Noel N.; Parsons-Moss, Tashi; Ashby, Paul D.; Gates, Jacklyn M.; Stavsetra, Liv; Gregorich, Kenneth E.; Nitsche, Heino

    2008-09-15

    Thulium(III) oxide (Tm{sub 2}O{sub 3}) targets prepared by the polymer-assisted deposition (PAD) method were irradiated by heavy-ion beams to test the method's feasibility for nuclear science applications. Targets were prepared on silicon nitride backings (thickness of 1000 nm, 344 {micro}g/cm{sup 2}) and were irradiated with an {sup 40}Ar beam at laboratory frame energy of {approx}210 MeV (50 particle nA). The root mean squared (RMS) roughness prior to irradiation is 1.1 nm for a {approx}250 nm ({approx}220 {micro}g/cm{sup 2}) Tm{sub 2}O{sub 3} target, and an RMS roughness of 2.0 nm after irradiation was measured by atomic force microscopy (AFM). Scanning electron microscopy of the irradiated target reveals no significant differences in surface homogeneity when compared to imaging prior to irradiation. Target flaking was not observed from monitoring Rutherford scattered particles as a function of time.

  4. Polymer-assisted iron oxide magnetic nanoparticle immobilized keratinase

    NASA Astrophysics Data System (ADS)

    Konwarh, Rocktotpal; Karak, Niranjan; Rai, Sudhir Kumar; Mukherjee, Ashis Kumar

    2009-06-01

    Nanotechnology holds the prospect for avant-garde changes to improve the performance of materials in various sectors. The domain of enzyme biotechnology is no exception. Immobilization of industrially important enzymes onto nanomaterials, with improved performance, would pave the way to myriad application-based commercialization. Keratinase produced by Bacillus subtilis was immobilized onto poly(ethylene glycol)-supported Fe3O4 superparamagnetic nanoparticles. The optimization process showed that the highest enzyme activity was noted when immobilized onto cyanamide-activated PEG-assisted MNP prepared under conditions of 25 °C and pH 7.2 of the reaction mixture before addition of H2O2 (3% w/w), 2% (w/v) PEG6000 and 0.062:1 molar ratio of PEG to FeCl2·4H2O. Further statistical optimization using response surface methodology yielded an R2 value that could explain more than 94% of the sample variations. Along with the magnetization studies, the immobilization of the enzyme onto the PEG-assisted MNP was characterized by UV, XRD, FTIR and TEM. The immobilization process had resulted in an almost fourfold increase in the enzyme activity over the free enzyme. Furthermore, the immobilized enzyme exhibited a significant thermostability, storage stability and recyclability. The leather-industry-oriented application of the immobilized enzyme was tested for the dehairing of goat-skin.

  5. Field effect devices and sensors based on electrospun polymer assisted tin oxide nanoribbons.

    PubMed

    Rojas, Richard; Meléndez, Anamaris; Ramos, Idalia; Santiago-Avilés, Jorge J; Pinto, Nicholas J

    2010-04-01

    Electrospinning is presented as a facile method of preparing relatively long tin oxide (SnO2) nanofibers that are robust and stable in air. Upon heat treatment, the fibers collapse into a ribbon-like structure with surfaces that are not smooth, rather, are marked with several interconnected pathways. These nanoribbons were electrically characterized in a field effect transistor configuration in vacuum, with and without ultra violet (UV) light exposure. The resultant variable resistor device exhibits n-type behavior having an on/off ratio of approximately 6000. The devices show a direct response to UV with faster response times upon exposure to longer wavelength light. In the presence of UV, the device conductance and mobility increases, reaching a value approximately 2 cm2/-s for the 364 nm UV light source, comparable to amorphous Si. PMID:20355506

  6. Copper-catalyzed Huisgen 1,3-dipolar cycloaddition under oxidative conditions: polymer-assisted assembly of 4-acyl-1-substituted-1,2,3-triazoles.

    PubMed

    Diz, Paula M; Coelho, Alberto; El Maatougui, Abdelaziz; Azuaje, Jhonny; Caamaño, Olga; Gil, Álvaro; Sotelo, Eddy

    2013-07-01

    We herein document the first example of a reliable copper-catalyzed Huisgen 1,3-dipolar cycloaddition under oxidative conditions. The combined use of two polymer-supported reagents (polystyrene-1,5,7-triazabicyclo[4,4,0]dec-5-ene/Cu and polystyrene-2-iodoxybenzamide) overcomes the thermodynamic instability of copper(I) species toward oxidation, enabling the reliable Cu-catalyzed Huisgen 1,3-dipolar cycloadditions in the presence of an oxidant agent. This polymer-assisted pathway, not feasible under conventional homogeneous conditions, provides a direct assembly of 4-acyl-1-substituted-1,2,3-triazoles, contributing to expand the reliability and scope of Cu(I)-catalyzed alkyne-azide cycloaddition.

  7. Polymer-assisted deposition of films

    DOEpatents

    McCleskey, Thomas M.; Burrell, Anthony K.; Jia, Quanxi; Lin, Yuan

    2008-04-29

    A polymer assisted deposition process for deposition of metal oxide films is presented. The process includes solutions of one or more metal precursor and soluble polymers having binding properties for the one or more metal precursor. After a coating operation, the resultant coating is heated at high temperatures to yield metal oxide films. Such films can be epitaxial in structure and can be of optical quality. The process can be organic solvent-free.

  8. Polymer-assisted deposition of films

    DOEpatents

    McCleskey, Thomas M.; Burrell; Anthony K.; Jia; Quanxi; Lin; Yuan

    2009-10-20

    A polymer assisted deposition process for deposition of metal oxide films and the like is presented. The process includes solutions of one or more metal precursor and soluble polymers having binding properties for the one or more metal precursor. After a coating operation, the resultant coating is heated at high temperatures to yield metal oxide films and the like. Such films can be epitaxial in structure and can be of optical quality. The process can be organic solvent-free.

  9. Linking Precursor Alterations to Nanoscale Structure and Optical Transparency in Polymer Assisted Fast-Rate Dip-Coating of Vanadium Oxide Thin Films

    PubMed Central

    Glynn, Colm; Creedon, Donal; Geaney, Hugh; Armstrong, Eileen; Collins, Timothy; Morris, Michael A.; Dwyer, Colm O’

    2015-01-01

    Solution processed metal oxide thin films are important for modern optoelectronic devices ranging from thin film transistors to photovoltaics and for functional optical coatings. Solution processed techniques such as dip-coating, allow thin films to be rapidly deposited over a large range of surfaces including curved, flexible or plastic substrates without extensive processing of comparative vapour or physical deposition methods. To increase the effectiveness and versatility of dip-coated thin films, alterations to commonly used precursors can be made that facilitate controlled thin film deposition. The effects of polymer assisted deposition and changes in solvent-alkoxide dilution on the morphology, structure, optoelectronic properties and crystallinity of vanadium pentoxide thin films was studied using a dip-coating method using a substrate withdrawal speed within the fast-rate draining regime. The formation of sub-100 nm thin films could be achieved rapidly from dilute alkoxide based precursor solutions with high optical transmission in the visible, linked to the phase and film structure. The effects of the polymer addition was shown to change the crystallized vanadium pentoxide thin films from a granular surface structure to a polycrystalline structure composed of a high density of smaller in-plane grains, resulting in a uniform surface morphology with lower thickness and roughness. PMID:26123117

  10. Polymer-assisted solution processing of Mo-doped indium oxide thin films: high-mobility and carrier-scattering mechanisms

    NASA Astrophysics Data System (ADS)

    Vishwanath, Sujaya Kumar; Cho, Kuk Young; Kim, Jihoon

    2016-04-01

    Mo-doped indium oxide (MIO) transparent conducting films have been prepared by a polymer-assisted solution (PAS) process. Both Mo- and In-PASs have been formulated by coordinating Mo- and In-anionic complexes with polyethyleneimine. The final MIO-PAS coating solution was prepared by adding Mo-PAS and In-PAS with Mo concentration in solution ranging from 0 at% to 2.5 at%. The structural, optical and electrical properties of MIO films spin-coated on the glass substrates were characterized. The optimum Mo concentration leading to the best electrical and optical properties was 1.5 at%, showing a low resistivity of 3.9  ×  10-3 Ω  ṡ  cm with high mobility of 43 cm2 V-1 s-1 and high transmittance from visible to near infrared regions. The carrier-transport mechanism in the PAS-processed MIO film was investigated by applying a theoretical scattering model (Brook-Herring-Dingle theory) to Hall mobility data. The scattering model confirms that the ionized and neutral impurities play important roles as dominant scattering centers in the PAS-processed MIO films.

  11. Iron oxide surfaces

    NASA Astrophysics Data System (ADS)

    Parkinson, Gareth S.

    2016-03-01

    The current status of knowledge regarding the surfaces of the iron oxides, magnetite (Fe3O4), maghemite (γ-Fe2O3), haematite (α-Fe2O3), and wüstite (Fe1-xO) is reviewed. The paper starts with a summary of applications where iron oxide surfaces play a major role, including corrosion, catalysis, spintronics, magnetic nanoparticles (MNPs), biomedicine, photoelectrochemical water splitting and groundwater remediation. The bulk structure and properties are then briefly presented; each compound is based on a close-packed anion lattice, with a different distribution and oxidation state of the Fe cations in interstitial sites. The bulk defect chemistry is dominated by cation vacancies and interstitials (not oxygen vacancies) and this provides the context to understand iron oxide surfaces, which represent the front line in reduction and oxidation processes. Fe diffuses in and out from the bulk in response to the O2 chemical potential, forming sometimes complex intermediate phases at the surface. For example, α-Fe2O3 adopts Fe3O4-like surfaces in reducing conditions, and Fe3O4 adopts Fe1-xO-like structures in further reducing conditions still. It is argued that known bulk defect structures are an excellent starting point in building models for iron oxide surfaces. The atomic-scale structure of the low-index surfaces of iron oxides is the major focus of this review. Fe3O4 is the most studied iron oxide in surface science, primarily because its stability range corresponds nicely to the ultra-high vacuum environment. It is also an electrical conductor, which makes it straightforward to study with the most commonly used surface science methods such as photoemission spectroscopies (XPS, UPS) and scanning tunneling microscopy (STM). The impact of the surfaces on the measurement of bulk properties such as magnetism, the Verwey transition and the (predicted) half-metallicity is discussed. The best understood iron oxide surface at present is probably Fe3O4(100); the structure is

  12. Iron oxide surfaces

    NASA Astrophysics Data System (ADS)

    Parkinson, Gareth S.

    2016-03-01

    The current status of knowledge regarding the surfaces of the iron oxides, magnetite (Fe3O4), maghemite (γ-Fe2O3), haematite (α-Fe2O3), and wüstite (Fe1-xO) is reviewed. The paper starts with a summary of applications where iron oxide surfaces play a major role, including corrosion, catalysis, spintronics, magnetic nanoparticles (MNPs), biomedicine, photoelectrochemical water splitting and groundwater remediation. The bulk structure and properties are then briefly presented; each compound is based on a close-packed anion lattice, with a different distribution and oxidation state of the Fe cations in interstitial sites. The bulk defect chemistry is dominated by cation vacancies and interstitials (not oxygen vacancies) and this provides the context to understand iron oxide surfaces, which represent the front line in reduction and oxidation processes. Fe diffuses in and out from the bulk in response to the O2 chemical potential, forming sometimes complex intermediate phases at the surface. For example, α-Fe2O3 adopts Fe3O4-like surfaces in reducing conditions, and Fe3O4 adopts Fe1-xO-like structures in further reducing conditions still. It is argued that known bulk defect structures are an excellent starting point in building models for iron oxide surfaces. The atomic-scale structure of the low-index surfaces of iron oxides is the major focus of this review. Fe3O4 is the most studied iron oxide in surface science, primarily because its stability range corresponds nicely to the ultra-high vacuum environment. It is also an electrical conductor, which makes it straightforward to study with the most commonly used surface science methods such as photoemission spectroscopies (XPS, UPS) and scanning tunneling microscopy (STM). The impact of the surfaces on the measurement of bulk properties such as magnetism, the Verwey transition and the (predicted) half-metallicity is discussed. The best understood iron oxide surface at present is probably Fe3O4(100); the structure is

  13. 21 CFR 186.1374 - Iron oxides.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Iron oxides. 186.1374 Section 186.1374 Food and... Substances Affirmed as GRAS § 186.1374 Iron oxides. (a) Iron oxides (oxides of iron, CAS Reg. No. 1332-37-2) are undefined mixtures of iron (II) oxide (CAS Reg. No. 1345-25-1, black cubic crystals) and iron...

  14. 21 CFR 186.1374 - Iron oxides.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Iron oxides. 186.1374 Section 186.1374 Food and... Substances Affirmed as GRAS § 186.1374 Iron oxides. (a) Iron oxides (oxides of iron, CAS Reg. No. 1332-37-2) are undefined mixtures of iron (II) oxide (CAS Reg. No. 1345-25-1, black cubic crystals) and iron...

  15. Effects of H{sub 2} plasma treatment on the electrical properties of titanium-doped indium oxide films prepared by polymer-assisted deposition

    SciTech Connect

    Hwang, Joo-Sang; Lee, Ji-Myon; Vishwanath, Sujaya Kumar; Kim, Jihoon

    2015-07-15

    The effects of hydrogen (H{sub 2}) plasma on the optical and electrical properties of titanium-doped InO (TIO) grown on glass substrates using polymer-assisted deposition are reported. Samples were exposed to H{sub 2} plasma formed by inductively coupled plasma (ICP). After plasma treatment at a power of 100 W, the sheet resistance of the TIO films decreased from 11 000 to 285 Ω/sq. Additionally, the Hall mobility and sheet carrier concentration of the films increased as the ICP source power was increased to 100 W, without affecting the optical transmittance of the films, due to the removal of the polymer residues and the formation of oxygen vacancies.

  16. 21 CFR 73.2250 - Iron oxides.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Iron oxides. 73.2250 Section 73.2250 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2250 Iron oxides. (a) Identity. The color additives iron oxides consist of any one or any combination of synthetically prepared iron oxides, including...

  17. 21 CFR 73.2250 - Iron oxides.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Iron oxides. 73.2250 Section 73.2250 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2250 Iron oxides. (a) Identity. The color additives iron oxides consist of any one or any combination of synthetically prepared iron oxides, including...

  18. Precursors for the polymer-assisted deposition of films

    DOEpatents

    McCleskey, Thomas M.; Burrell, Anthony K.; Jia, Quanxi; Lin, Yuan

    2013-09-10

    A polymer assisted deposition process for deposition of metal oxide films is presented. The process includes solutions of one or more metal precursor and soluble polymers having binding properties for the one or more metal precursor. After a coating operation, the resultant coating is heated at high temperatures to yield metal oxide films. Such films can be epitaxial in structure and can be of optical quality. The process can be organic solvent-free.

  19. 21 CFR 186.1374 - Iron oxides.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

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

  20. 21 CFR 186.1374 - Iron oxides.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

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

  1. 46 CFR 148.275 - Iron oxide, spent; iron sponge, spent.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Iron oxide, spent; iron sponge, spent. 148.275 Section... § 148.275 Iron oxide, spent; iron sponge, spent. (a) Before spent iron oxide or spent iron sponge is... been cooled and weathered for at least eight weeks. (b) Both spent iron oxide and spent iron sponge...

  2. 21 CFR 73.3125 - Iron oxides.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Iron oxides. 73.3125 Section 73.3125 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Medical Devices § 73.3125 Iron oxides. (a) Identity and specifications. The color additive iron oxides (CAS Reg. No. 1332-37-2), Color Index No. 77491, shall conform...

  3. 21 CFR 73.3125 - Iron oxides.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Iron oxides. 73.3125 Section 73.3125 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Medical Devices § 73.3125 Iron oxides. (a) Identity and specifications. The color additive iron oxides (CAS Reg. No. 1332-37-2), Color Index No. 77491, shall conform...

  4. 21 CFR 73.3125 - Iron oxides.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Iron oxides. 73.3125 Section 73.3125 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Medical Devices § 73.3125 Iron oxides. (a) Identity and specifications. The color additive iron oxides (CAS Reg. No. 1332-37-2), Color Index No. 77491, shall conform...

  5. Iron oxidation by Thiobacillus ferrooxidans

    SciTech Connect

    Kang, Sunki; Sproull, R.D.

    1991-12-31

    Several investigators have shown that microorganisms are involved in many naturally occurring oxidation processes. At present, microbial leaching, which is the solubilization of metals catalyzed by microorganisms, is widely used commercially to produce copper, and to a lesser extent uranium, from low-grade mining wastes. Microbial leaching can also be used as a pretreatment step in the mining of precious metals, such as gold and silver. In this application, the solubilization of pyrite makes the precious metals more accessible for cyanide leaching. Because ferrous iron oxidation is such an important reaction in microbial leaching operations, this study was undertaken to examine factors affecting the rate of ferrous iron oxidation in the presence of T. ferrooxidans.

  6. High temperature oxidation of iron-iron oxide core-shell nanowires composed of iron nanoparticles.

    PubMed

    Krajewski, M; Brzozka, K; Lin, W S; Lin, H M; Tokarczyk, M; Borysiuk, J; Kowalski, G; Wasik, D

    2016-02-01

    This work describes an oxidation process of iron-iron oxide core-shell nanowires at temperatures between 100 °C and 800 °C. The studied nanomaterial was synthesized through a simple chemical reduction of iron trichloride in an external magnetic field under a constant flow of argon. The electron microscopy investigations allowed determining that the as-prepared nanowires were composed of self-assembled iron nanoparticles which were covered by a 3 nm thick oxide shell and separated from each other by a thin interface layer. Both these layers exhibited an amorphous or highly-disordered character which was traced by means of transmission electron microscopy and Mössbauer spectroscopy. The thermal oxidation was carried out under a constant flow of argon which contained the traces of oxygen. The first stage of process was related to slow transformations of amorphous Fe and amorphous iron oxides into crystalline phases and disappearance of interfaces between iron nanoparticles forming the studied nanomaterial (range: 25-300 °C). After that, the crystalline iron core and iron oxide shell became oxidized and signals for different compositions of iron oxide sheath were observed (range: 300-800 °C) using X-ray diffraction, Raman spectroscopy and Mössbauer spectroscopy. According to the thermal gravimetric analysis, the nanowires heated up to 800 °C under argon atmosphere gained 37% of mass with respect to their initial weight. The structure of the studied nanomaterial oxidized at 800 °C was mainly composed of α-Fe2O3 (∼ 93%). Moreover, iron nanowires treated above 600 °C lost their wire-like shape due to their shrinkage and collapse caused by the void coalescence. PMID:26766540

  7. 21 CFR 73.2250 - Iron oxides.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2250 Iron oxides. (a) Identity. The color additives iron... per million. (c) Uses and restrictions. Iron oxides are safe for use in coloring cosmetics generally, including cosmetics applied to the area of the eye, in amounts consistent with good manufacturing...

  8. 21 CFR 73.2250 - Iron oxides.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2250 Iron oxides. (a) Identity. The color additives iron... per million. (c) Uses and restrictions. Iron oxides are safe for use in coloring cosmetics generally, including cosmetics applied to the area of the eye, in amounts consistent with good manufacturing...

  9. 21 CFR 73.2250 - Iron oxides.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2250 Iron oxides. (a) Identity. The color additives iron... per million. (c) Uses and restrictions. Iron oxides are safe for use in coloring cosmetics generally, including cosmetics applied to the area of the eye, in amounts consistent with good manufacturing...

  10. Microorganisms pumping iron: anaerobic microbial iron oxidation and reduction.

    PubMed

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

    2006-10-01

    Iron (Fe) has long been a recognized physiological requirement for life, yet for many microorganisms that persist in water, soils and sediments, its role extends well beyond that of a nutritional necessity. Fe(II) can function as an electron source for iron-oxidizing microorganisms under both oxic and anoxic conditions and Fe(III) can function as a terminal electron acceptor under anoxic conditions for iron-reducing microorganisms. Given that iron is the fourth most abundant element in the Earth's crust, iron redox reactions have the potential to support substantial microbial populations in soil and sedimentary environments. As such, biological iron apportionment has been described as one of the most ancient forms of microbial metabolism on Earth, and as a conceivable extraterrestrial metabolism on other iron-mineral-rich planets such as Mars. Furthermore, the metabolic versatility of the microorganisms involved in these reactions has resulted in the development of biotechnological applications to remediate contaminated environments and harvest energy.

  11. Indium Sorption to Iron Oxides

    NASA Astrophysics Data System (ADS)

    White, S. J.; Sacco, S. A.; Hemond, H.; Hussain, F. A.; Runkel, R. L.; Walton-Day, K. E.; Kimball, B. A.; Shine, J. P.

    2014-12-01

    Indium is an increasingly important metal in semiconductors and electronics, and its use is growing rapidly as a semiconductive coating (as indium tin oxide) for liquid crystal displays (LCDs) and flat panel displays. It also has uses in important energy technologies such as light emitting diodes (LEDs) and photovoltaic cells. Despite its rapid increase in use, very little is known about the environmental behavior of indium, and concerns are being raised over the potential health effects of this emerging metal contaminant. One source of indium to the environment is acid mine drainage from the mining of lead, zinc, and copper sulfides. In our previous studies of a stream in Colorado influenced by acid mine drainage from lead and zinc mining activities, indium concentrations were found to be 10,000 times those found in uncontaminated rivers. However, the speciation and mobility of indium could not be reliably modeled because sorption constants to environmental sorbents have not been determined. In this study, we generate sorption constants for indium to ferrihydrite in the laboratory over a range of pHs, sorbent to sorbate ratios, and ionic strengths. Ferrihydrite is one of the most important sorbents in natural systems, and sorption to amorphous iron oxides such as ferrihydrite is thought to be one of the main removal mechanisms of metals from the dissolved phase in aqueous environments. Because of its relatively low solubility, we also find that indium hydroxide precipitation can dominate indium's partitioning at micromolar concentrations of indium. This precipitation may be important in describing indium's behavior in our study stream in Colorado, where modeling sorption to iron-oxides does not explain the complete removal of indium from the dissolved phase when the pH of the system is artificially raised to above 8. This study contributes much-needed data about indium's aqueous behavior, in order to better understand its fate, transport, and impacts in the

  12. Iron biomineralization by anaerobic neutrophilic iron-oxidizing bacteria

    NASA Astrophysics Data System (ADS)

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

    2009-02-01

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

  13. Tannin biosynthesis of iron oxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Herrera-Becerra, R.; Rius, J. L.; Zorrilla, C.

    2010-08-01

    In this work, iron oxide nanoparticles synthesized with gallic acid and tannic acid are characterized using High-Resolution Transmission Electron Microscopy (HRTEM). Its size, form, and structure are compared with nanoparticles obtained previously using alfalfa biomass in order to find a simpler, consistent, and environmentally friendly method in the production of iron oxide nanoparticles.

  14. 21 CFR 73.3125 - Iron oxides.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Iron oxides. 73.3125 Section 73.3125 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Medical Devices § 73.3125 Iron oxides. (a) Identity and...

  15. 21 CFR 186.1374 - Iron oxides.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... iron (II) oxide (CAS Reg. No. 1345-25-1, black cubic crystals) and iron (III) oxide (CAS Reg. No. 1309-37-1, red-brown to black trigonal crystals). (b) In accordance with § 186.1(b)(1), the ingredient...

  16. Enzymatic iron oxidation by Leptothrix discophora: identification of an iron-oxidizing protein.

    PubMed Central

    Corstjens, P L; de Vrind, J P; Westbroek, P; de Vrind-de Jong, E W

    1992-01-01

    An iron-oxidizing factor was identified in the spent culture medium of the iron- and manganese-oxidizing bacterial strain Leptothrix discophora SS-1. It appeared to be a protein, with an apparent molecular weight of approximately 150,000. Its activity could be demonstrated after fractionation of the spent medium by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. A spontaneous mutant of L. discophora SS-1 was isolated which excreted neither manganese- nor iron-oxidizing activity, whereas excretion of other proteins seemed to be unaffected. Although the excretion of both metal-oxidizing factors was probably linked, the difference in other properties suggests that manganese and iron oxidation represent two different pathways. With a dot-blot assay, it was established that different bacterial species have different metal-oxidizing capacities. Whereas L. discophora oxidized both iron and manganese, Sphaerotilus natans oxidized only iron and two Pseudomonas spp. oxidized only manganese. Images PMID:1610168

  17. Enzymatic iron oxidation by Leptothrix discophora: identification of an iron-oxidizing protein.

    PubMed

    Corstjens, P L; de Vrind, J P; Westbroek, P; de Vrind-de Jong, E W

    1992-02-01

    An iron-oxidizing factor was identified in the spent culture medium of the iron- and manganese-oxidizing bacterial strain Leptothrix discophora SS-1. It appeared to be a protein, with an apparent molecular weight of approximately 150,000. Its activity could be demonstrated after fractionation of the spent medium by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. A spontaneous mutant of L. discophora SS-1 was isolated which excreted neither manganese- nor iron-oxidizing activity, whereas excretion of other proteins seemed to be unaffected. Although the excretion of both metal-oxidizing factors was probably linked, the difference in other properties suggests that manganese and iron oxidation represent two different pathways. With a dot-blot assay, it was established that different bacterial species have different metal-oxidizing capacities. Whereas L. discophora oxidized both iron and manganese, Sphaerotilus natans oxidized only iron and two Pseudomonas spp. oxidized only manganese. PMID:1610168

  18. Controllable Synthesis of Mesoporous Iron Oxide Nanoparticle Assemblies for Chemoselective Catalytic Reduction of Nitroarenes.

    PubMed

    Papadas, Ioannis T; Fountoulaki, Stella; Lykakis, Ioannis N; Armatas, Gerasimos S

    2016-03-18

    Iron(III) oxide is a low-cost material with applications ranging from electronics to magnetism, and catalysis. Recent efforts have targeted new nanostructured forms of Fe2O3 with high surface area-to-volume ratio and large pore volume. Herein, the synthesis of 3D mesoporous networks consisting of 4-5 nm γ-Fe2O3 nanoparticles by a polymer-assisted aggregating self-assembly method is reported. Iron oxide assemblies obtained from the hybrid networks after heat treatment have an open-pore structure with high surface area (up to 167 m(2)g(-1)) and uniform pores (ca. 6.3 nm). The constituent iron oxide nanocrystals can undergo controllable phase transition from γ-Fe2O3 to α-Fe2O3 and to Fe3O4 under different annealing conditions while maintaining the 3D structure and open porosity. These new ensemble structures exhibit high catalytic activity and stability for the selective reduction of aryl and alkyl nitro compounds to the corresponding aryl amines and oximes, even in large-scale synthesis. PMID:26880681

  19. Controllable Synthesis of Mesoporous Iron Oxide Nanoparticle Assemblies for Chemoselective Catalytic Reduction of Nitroarenes.

    PubMed

    Papadas, Ioannis T; Fountoulaki, Stella; Lykakis, Ioannis N; Armatas, Gerasimos S

    2016-03-18

    Iron(III) oxide is a low-cost material with applications ranging from electronics to magnetism, and catalysis. Recent efforts have targeted new nanostructured forms of Fe2O3 with high surface area-to-volume ratio and large pore volume. Herein, the synthesis of 3D mesoporous networks consisting of 4-5 nm γ-Fe2O3 nanoparticles by a polymer-assisted aggregating self-assembly method is reported. Iron oxide assemblies obtained from the hybrid networks after heat treatment have an open-pore structure with high surface area (up to 167 m(2)g(-1)) and uniform pores (ca. 6.3 nm). The constituent iron oxide nanocrystals can undergo controllable phase transition from γ-Fe2O3 to α-Fe2O3 and to Fe3O4 under different annealing conditions while maintaining the 3D structure and open porosity. These new ensemble structures exhibit high catalytic activity and stability for the selective reduction of aryl and alkyl nitro compounds to the corresponding aryl amines and oximes, even in large-scale synthesis.

  20. Facile and sustainable synthesis of shaped iron oxide nanoparticles: effect of iron precursor salts on the shapes of iron oxides.

    PubMed

    Sayed, Farheen N; Polshettiwar, Vivek

    2015-05-05

    A facile and sustainable protocol for synthesis of six different shaped iron oxides is developed. Notably, all the six shapes of iron oxides can be synthesised using exactly same synthetic protocol, by simply changing the precursor iron salts. Several of the synthesised shapes are not reported before. This novel protocol is relatively easy to implement and could contribute to overcome the challenge of obtaining various shaped iron oxides in economical and sustainable manner.

  1. Facile and Sustainable Synthesis of Shaped Iron Oxide Nanoparticles: Effect of Iron Precursor Salts on the Shapes of Iron Oxides

    PubMed Central

    Sayed, Farheen N.; Polshettiwar, Vivek

    2015-01-01

    A facile and sustainable protocol for synthesis of six different shaped iron oxides is developed. Notably, all the six shapes of iron oxides can be synthesised using exactly same synthetic protocol, by simply changing the precursor iron salts. Several of the synthesised shapes are not reported before. This novel protocol is relatively easy to implement and could contribute to overcome the challenge of obtaining various shaped iron oxides in economical and sustainable manner. PMID:25939969

  2. On the formation of iron(III) oxides via oxidation of iron(II)

    SciTech Connect

    Bongiovanni, R.; Pelizzetti, E.; Borgarello, E.; Meisel, D.

    1994-09-01

    Formation of iron oxides in aqueous salt solutions is reviewed. The discussion is focused on the oxidation of iron(II) and the following hydrolysis process that leads to the formation of a solid phase from homogeneous solutions. Results from our own studies on the kinetics of the oxidation reactions and the ensuing growth processes are presented.

  3. Polymer-assisted deposition of films

    DOEpatents

    McCleskey,Thomas M.; Burrell,Anthony K.; Jia,Quanxi; Lin,Yuan

    2012-02-28

    A polymer assisted deposition process for deposition of metal nitride films and the like is presented. The process includes solutions of one or more metal precursor and soluble polymers having binding properties for the one or more metal precursor. After a coating operation, the resultant coating is heated at high temperatures under a suitable atmosphere to yield metal nitride films and the like. Such films can be conformal on a variety of substrates including non-planar substrates. In some instances, the films can be epitaxial in structure and can be of optical quality. The process can be organic solvent-free.

  4. Arsenic Adsorption Onto Iron Oxides Minerals

    NASA Astrophysics Data System (ADS)

    Aredes, S.; Klein, B.; Pawlik, M.

    2004-12-01

    The predominant form of arsenic in water is as an inorganic ion. Under different redox conditions arsenic in water is stable in the +5 and +3 oxidation states. Arsenic oxidation state governs its toxicity, chemical form and solubility in natural and disturbed environments. As (III) is found in anoxic environments such as ground water , it is toxic and the common species is the neutral form, H3AsO3. As (V) is found in aerobic conditions such as surface water, it is less toxic and the common species in water are: H2AsO4 - and HAsO4 {- 2}. The water pH determines the predominant arsenate or arsenite species, however, both forms of arsenic can be detected in natural water systems. Iron oxides minerals often form in natural waters and sediments at oxic-anoxic boundaries. Over time they undergo transformation to crystalline forms, such as goethite or hematite. Both As(V) and As(III) sorbs strongly to iron oxides, however the sorption behavior of arsenic is dependent on its oxidation state and the mineralogy of the iron oxides. Competition between arsenic and others ions, such fluoride, sulphate and phosphate also play a role. On the other hand, calcium may increase arsenic adsorption onto iron oxides. Electrokinetic studies and adsorption experiments were carried out in order to determine which conditions favour arsenic adsorption. Hematite, goethite and magnetite as iron based sorbents were used. Test were also conducted with a laterite soil rich in iron minerals. The focus of this study is to evaluate physical and chemical conditions which favour arsenic adsorption onto iron oxides minerals, the results contribute to an understanding of arsenic behaviour in natural and disturbed environments. Furthermore, results could contribute in developing an appropriate remediation technology for arsenic removal in water using iron oxides minerals.

  5. The Irony of Iron – Biogenic Iron Oxides as an Iron Source to the Ocean

    PubMed Central

    Emerson, David

    2016-01-01

    Primary productivity in at least a third of the sunlit open ocean is thought to be iron-limited. Primary sources of dissolved iron (dFe) to the ocean are hydrothermal venting, flux from the sediments along continental margins, and airborne dust. This article provides a general review of sources of hydrothermal and sedimentary iron to the ocean, and speculates upon the role that iron-cycling microbes play in controlling iron dynamics from these sources. Special attention is paid to iron-oxidizing bacteria (FeOB) that live by oxidizing iron and producing biogenic iron oxides as waste products. The presence and ubiquity of FeOB both at hydrothermal systems and in sediments is only beginning to be appreciated. The biogenic oxides they produce have unique properties that could contribute significantly to the dynamics of dFe in the ocean. Changes in the physical and chemical characteristics of the ocean due to climate change and ocean acidification will undoubtedly impact the microbial iron cycle. A better understanding of the contemporary role of microbes in the iron cycle will help in predicting how these changes could ultimately influence marine primary productivity. PMID:26779157

  6. The Irony of Iron - Biogenic Iron Oxides as an Iron Source to the Ocean.

    PubMed

    Emerson, David

    2015-01-01

    Primary productivity in at least a third of the sunlit open ocean is thought to be iron-limited. Primary sources of dissolved iron (dFe) to the ocean are hydrothermal venting, flux from the sediments along continental margins, and airborne dust. This article provides a general review of sources of hydrothermal and sedimentary iron to the ocean, and speculates upon the role that iron-cycling microbes play in controlling iron dynamics from these sources. Special attention is paid to iron-oxidizing bacteria (FeOB) that live by oxidizing iron and producing biogenic iron oxides as waste products. The presence and ubiquity of FeOB both at hydrothermal systems and in sediments is only beginning to be appreciated. The biogenic oxides they produce have unique properties that could contribute significantly to the dynamics of dFe in the ocean. Changes in the physical and chemical characteristics of the ocean due to climate change and ocean acidification will undoubtedly impact the microbial iron cycle. A better understanding of the contemporary role of microbes in the iron cycle will help in predicting how these changes could ultimately influence marine primary productivity.

  7. The Irony of Iron - Biogenic Iron Oxides as an Iron Source to the Ocean.

    PubMed

    Emerson, David

    2015-01-01

    Primary productivity in at least a third of the sunlit open ocean is thought to be iron-limited. Primary sources of dissolved iron (dFe) to the ocean are hydrothermal venting, flux from the sediments along continental margins, and airborne dust. This article provides a general review of sources of hydrothermal and sedimentary iron to the ocean, and speculates upon the role that iron-cycling microbes play in controlling iron dynamics from these sources. Special attention is paid to iron-oxidizing bacteria (FeOB) that live by oxidizing iron and producing biogenic iron oxides as waste products. The presence and ubiquity of FeOB both at hydrothermal systems and in sediments is only beginning to be appreciated. The biogenic oxides they produce have unique properties that could contribute significantly to the dynamics of dFe in the ocean. Changes in the physical and chemical characteristics of the ocean due to climate change and ocean acidification will undoubtedly impact the microbial iron cycle. A better understanding of the contemporary role of microbes in the iron cycle will help in predicting how these changes could ultimately influence marine primary productivity. PMID:26779157

  8. Removal of metallic iron on oxide slags

    SciTech Connect

    Shannon, G.N.; Fruehan, R.J.; Sridhar, S.

    2009-10-15

    It is possible, in some cases, for ground coal particles to react with gasifier gas during combustion, allowing the ash material in the coal to form phases besides the expected slag phase. One of these phases is metallic iron, because some gasifiers are designed to operate under a reducing atmosphere (pO{sub 2}) of approximately 10{sup -4} atm). Metallic iron can become entrained in the gas stream and deposit on, and foul, downstream equipment. To improve the understanding of the reaction between different metallic iron particles and gas, which eventually oxidizes them, and the slag that the resulting oxide dissolves in, the kinetics of iron reaction on slag were predicted using gas-phase mass-transfer limitations for the reaction and were compared with diffusion in the slag; the reaction itself was observed under confocal scanning laser microscopy. The expected rates for iron droplet removal are provided based on the size and effective partial pressure of oxygen, and it is found that decarburization occurs before iron reaction, leading to an extra 30- to 100-second delay for carbon-saturated particles vs pure iron particles. A pure metallic iron particle of 0.5 mg should be removed in about 220 seconds at 1400{sup o}C and in 160 seconds at 1600{sup o}C.

  9. Exploring Microbial Iron Oxidation in Wetland Soils

    NASA Astrophysics Data System (ADS)

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

    2009-04-01

    Iron is one of the most abundant elements on earth and is essential for life. Because of its importance, iron cycling and its interaction with other chemical and microbial processes has been the focus of many studies. Iron-oxidizing bacteria (FeOB) have been detected in a wide variety of environments. Among those is the rhizosphere of wetland plants roots which release oxygen into the soil creating suboxic conditions required by these organisms. It has been reported that in these rhizosphere microbial iron oxidation proceeds up to four orders of magnitude faster than strictly abiotic oxidation. On the roots of these wetland plants iron plaques are formed by microbial iron oxidation which are involved in the sequestering of heavy metals as well organic pollutants, which of great environmental significance.Despite their important role being catalysts of iron-cycling in wetland environments, little is known about the diversity and distribution of iron-oxidizing bacteria in various environments. This study aimed at developing a PCR-DGGE assay enabling the detection of iron oxidizers in wetland habitats. Gradient tubes were used to enrich iron-oxidizing bacteria. From these enrichments, a clone library was established based on the almost complete 16s rRNA gene using the universal bacterial primers 27f and 1492r. This clone library consisted of mainly α- and β-Proteobacteria, among which two major clusters were closely related to Gallionella spp. Specific probes and primers were developed on the basis of this 16S rRNA gene clone library. The newly designed Gallionella-specific 16S rRNA gene primer set 122f/998r was applied to community DNA obtained from three contrasting wetland environments, and the PCR products were used in denaturing gradient gel electrophoresis (DGGE) analysis. A second 16S rRNA gene clone library was constructed using the PCR products from one of our sampling sites amplified with the newly developed primer set 122f/998r. The cloned 16S rRNA gene

  10. Thermodynamics of Iron Oxidation in Metallurgical Slags

    NASA Astrophysics Data System (ADS)

    Matousek, Jan

    2012-11-01

    The state of oxidation of a pyrometallurgical process, given by the partial pressure of oxygen and the temperature, is one of the important properties monitored and controlled in the smelting and refining of iron and the nonferrous metals. This article reviews the thermodynamic background for this quantity and examines some empirical methods for its estimation and use. The emphasis is on copper smelting, but the same principles apply to iron, nickel, lead, and zinc processes.

  11. Laboratory experiments on the weathering of iron meteorites and carbonaceous chondrites by iron-oxidizing bacteria

    NASA Astrophysics Data System (ADS)

    Gronstal, A.; Pearson, V.; Kappler, A.; Dooris, C.; Anand, M.; Poitrasson, F.; Kee, T. P.; Cockell, C. S.

    2009-03-01

    Batch culture experiments were performed to investigate the weathering of meteoritic material by iron-oxidizing bacteria. The aerobic, acidophilic iron oxidizer (A. ferrooxidans) was capable of oxidizing iron from both carbonaceous chondrites (Murchison and Cold Bokkeveld) and iron meteorites (York and Casas Grandes). Preliminary iron isotope results clearly show contrasted iron pathways during oxidation with and without bacteria suggesting that a biological role in meteorite weathering could be distinguished isotopically. Anaerobic iron-oxidizers growing under pH-neutral conditions oxidized iron from iron meteorites. These results show that rapid biologicallymediated alteration of extraterrestrial materials can occur in both aerobic and anaerobic environments. These results also demonstrate that iron can act as a source of energy for microorganisms from both iron and carbonaceous chondrites in aerobic and anaerobic conditions with implications for life on the early Earth and the possible use of microorganisms to extract minerals from asteroidal material.

  12. Thermodynamic constraints on microbial iron oxide reduction

    NASA Astrophysics Data System (ADS)

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

    2003-04-01

    Iron oxides are ubiquitous reactive constituents of soils, sediments and aquifers. They exhibit large surface areas which bind trace metals, nutrients and organic molecules. Under suboxic conditions, iron oxides can reductively dissolve via several abiotic and microbial pathways. In particular, they serve as terminal electron acceptors for the oxidation of organic matter by iron reducing bacteria. The aim of our study was to determine the thermodynamic energy yields of dissimilatory iron reduction for different Fe(III) substrates. We used the facultative anaerobic gram-positive bacterium Shewanella putrefaciens as model iron reducing bacterium, with ferrihydrite, hematite, goethite or Fe(III)-salicylate as electron acceptor, and lactate as electron donor. Experiments were conducted in an anaerobic pH-stat batch reactor, equipped with a polarographic electrode to monitor in situ the dissolved ferrous iron activity. The stoichiometry of total Fe(II) production and acid consumption during the experiments indicated that lactate was oxidized to acetate. From the Fe(II) activity and redox potential measurements, free energy yields were calculated for Fe(III) reduction coupled to lactate oxidation. The results showed that the redox potential of the overall reaction was poised by equilibrium between the Fe(III)-substrate and aqueous Fe(II). Hence, the energy yields decreased in the order ferrihydrite > Fe(III)-salicylate > hematite > goethite. Accumulation of Fe(II) in solution only caused small decreases in the energy yields over the course of the experiments. Cessation of iron reduction, which was observed in all experiments, was therefore not due to thermodynamic limitation, but more likely reflected the decline in cell level of activity.

  13. Iron oxides in human spleen.

    PubMed

    Kopáni, Martin; Miglierini, Marcel; Lančok, Adriana; Dekan, Július; Čaplovicová, Mária; Jakubovský, Ján; Boča, Roman; Mrazova, Hedviga

    2015-10-01

    Iron is an essential element for fundamental cell functions and a catalyst for chemical reactions. Three samples extracted from the human spleen were investigated by scanning (SEM) and transmission electron microscopy (TEM), Mössbauer spectrometry (MS), and SQUID magnetometry. The sample with diagnosis of hemosiderosis (H) differs from that referring to hereditary spherocytosis and the reference sample. SEM reveals iron-rich micrometer-sized aggregate of various structures-tiny fibrils in hereditary spherocytosis sample and no fibrils in hemochromatosis. Hematite and magnetite particles from 2 to 6 μm in TEM with diffraction in all samples were shown. The SQUID magnetometry shows different amount of diamagnetic, paramagnetic and ferrimagnetic structures in the tissues. The MS results indicate contribution of ferromagnetically split sextets for all investigated samples. Their occurrence indicates that at least part of the sample is magnetically ordered below the critical temperature. The iron accumulation process is different in hereditary spherocytosis and hemosiderosis. This fact may be the reason of different iron crystallization.

  14. Iron oxides in human spleen.

    PubMed

    Kopáni, Martin; Miglierini, Marcel; Lančok, Adriana; Dekan, Július; Čaplovicová, Mária; Jakubovský, Ján; Boča, Roman; Mrazova, Hedviga

    2015-10-01

    Iron is an essential element for fundamental cell functions and a catalyst for chemical reactions. Three samples extracted from the human spleen were investigated by scanning (SEM) and transmission electron microscopy (TEM), Mössbauer spectrometry (MS), and SQUID magnetometry. The sample with diagnosis of hemosiderosis (H) differs from that referring to hereditary spherocytosis and the reference sample. SEM reveals iron-rich micrometer-sized aggregate of various structures-tiny fibrils in hereditary spherocytosis sample and no fibrils in hemochromatosis. Hematite and magnetite particles from 2 to 6 μm in TEM with diffraction in all samples were shown. The SQUID magnetometry shows different amount of diamagnetic, paramagnetic and ferrimagnetic structures in the tissues. The MS results indicate contribution of ferromagnetically split sextets for all investigated samples. Their occurrence indicates that at least part of the sample is magnetically ordered below the critical temperature. The iron accumulation process is different in hereditary spherocytosis and hemosiderosis. This fact may be the reason of different iron crystallization. PMID:26292972

  15. Catalytic iron oxide for lime regeneration in carbonaceous fuel combustion

    DOEpatents

    Shen, Ming-Shing; Yang, Ralph T.

    1980-01-01

    Lime utilization for sulfurous oxides absorption in fluidized combustion of carbonaceous fuels is improved by impregnation of porous lime particulates with iron oxide. The impregnation is achieved by spraying an aqueous solution of mixed iron sulfate and sulfite on the limestone before transfer to the fluidized bed combustor, whereby the iron compounds react with the limestone substrate to form iron oxide at the limestone surface. It is found that iron oxide present in the spent limestone acts as a catalyst to regenerate the spent limestone in a reducing environment. With only small quantities of iron oxide the calcium can be recycled at a significantly increased rate.

  16. Catalytic iron oxide for lime regeneration in carbonaceous fuel combustion

    SciTech Connect

    Shen, M.; Yang, R.T.

    1980-09-30

    Lime utilization for sulfurous oxides absorption in fluidized combustion of carbonaceous fuels is improved by impregnation of porous lime particulates with iron oxide. The impregnation is achieved by spraying an aqueous solution of mixed iron sulfate and sulfite on the limestone before transfer to the fluidized bed combustor, whereby the iron compounds react with the limestone substrate to form iron oxide at the limestone surface. It is found that iron oxide present in the spent limestone acts as a catalyst to regenerate the spent limestone in a reducing environment. With only small quantities of iron oxide the calcium can be recycled at a significantly increased rate.

  17. Defluoridation by Bacteriogenic Iron Oxides: Sorption Studies

    NASA Astrophysics Data System (ADS)

    Evans, K.; Ferris, F.

    2009-05-01

    At concentrations above 1 mg/L, fluoride in drinking water can lead to dental and skeletal fluorosis, a disease that causes mottling of the teeth, calcification of ligaments, crippling bone deformities and many other physiological disorders that can, ultimately, lead to death. Conservative estimates are that fluorosis afflicts tens of millions of people worldwide. As there is no treatment for fluorosis, prevention is the only means of controlling the disease. While numerous defluoridation techniques have been explored, no single method has been found to be both effective and inexpensive enough to implement widely. Our research began in India, with a large-scale geochemical study of the groundwater in a fluoride-contaminated region of Orissa. Having developed a better understanding of the geochemical relationships that exist between fluoride and other parameters present in an affected area, as well as the complex relationships that arise among those parameters that can impact the presence of fluoride, we began investigating certain remediation scenarios involving iron oxides. A common approach to remediation involves the partitioning of fluoride from groundwater by sorption onto a variety of materials, one of the most effective of which is iron oxide whose surface area acts as a scavenger for fluoride. In the presence of iron oxidizing bacteria, the oxidation rate of iron has been shown to be ˜6 times greater than in their absence; fluoride should, therefore, be removed from an aqueous environment by bacteriogenic iron oxides (BIOS) much more quickly than by abiotic iron oxides. Most recently, sorption studies have been conducted using both BIOS and synthetic hydrous ferric oxides in order to compare the behavior between biotic and abiotic sorbents. These studies have provided sorption isotherms that allow comparison of fluoride removed by sorption to BIOS versus synthetic iron oxides. Sorption affinity constants have also been determined, which allow for the

  18. 21 CFR 73.1200 - Synthetic iron oxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Synthetic iron oxide. 73.1200 Section 73.1200 Food... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1200 Synthetic iron oxide. (a) Identity. (1) The color additive synthetic iron oxide consists of any one or any combination of synthetically...

  19. 21 CFR 73.1200 - Synthetic iron oxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Synthetic iron oxide. 73.1200 Section 73.1200 Food... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1200 Synthetic iron oxide. (a) Identity. (1) The color additive synthetic iron oxide consists of any one or any combination of synthetically...

  20. 21 CFR 73.1200 - Synthetic iron oxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Synthetic iron oxide. 73.1200 Section 73.1200 Food... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1200 Synthetic iron oxide. (a) Identity. (1) The color additive synthetic iron oxide consists of any one or any combination of synthetically...

  1. 21 CFR 73.200 - Synthetic iron oxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Synthetic iron oxide. 73.200 Section 73.200 Food... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.200 Synthetic iron oxide. (a) Identity. (1) The color additive synthetic iron oxide consists of any one or any combination of synthetically...

  2. 21 CFR 73.200 - Synthetic iron oxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Synthetic iron oxide. 73.200 Section 73.200 Food... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.200 Synthetic iron oxide. (a) Identity. (1) The color additive synthetic iron oxide consists of any one or any combination of synthetically...

  3. 21 CFR 73.200 - Synthetic iron oxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Synthetic iron oxide. 73.200 Section 73.200 Food... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.200 Synthetic iron oxide. (a) Identity. (1) The color additive synthetic iron oxide consists of any one or any combination of synthetically...

  4. 21 CFR 73.1200 - Synthetic iron oxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Synthetic iron oxide. 73.1200 Section 73.1200 Food... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1200 Synthetic iron oxide. (a) Identity. (1) The color additive synthetic iron oxide consists of any one or any combination of synthetically...

  5. 21 CFR 73.1200 - Synthetic iron oxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Synthetic iron oxide. 73.1200 Section 73.1200 Food... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1200 Synthetic iron oxide. (a) Identity. (1) The color additive synthetic iron oxide consists of any one or any combination of synthetically...

  6. Chemical design of biocompatible iron oxide nanoparticles for medical applications.

    PubMed

    Ling, Daishun; Hyeon, Taeghwan

    2013-05-27

    Iron oxide nanoparticles are one of the most versatile and safe nanomaterials used in medicine. Recent progress in nanochemistry enables fine control of the size, crystallinity, uniformity, and surface properties of iron oxide nanoparticles. In this review, the synthesis of chemically designed biocompatible iron oxide nanoparticles with improved quality and reduced toxicity is discussed for use in diverse biomedical applications.

  7. Acid monolayer functionalized iron oxide nanoparticle catalysts

    NASA Astrophysics Data System (ADS)

    Ikenberry, Myles

    Superparamagnetic iron oxide nanoparticle functionalization is an area of intensely active research, with applications across disciplines such as biomedical science and heterogeneous catalysis. This work demonstrates the functionalization of iron oxide nanoparticles with a quasi-monolayer of 11-sulfoundecanoic acid, 10-phosphono-1-decanesulfonic acid, and 11-aminoundecanoic acid. The carboxylic and phosphonic moieties form bonds to the iron oxide particle core, while the sulfonic acid groups face outward where they are available for catalysis. The particles were characterized by thermogravimetric analysis (TGA), transmission electron microscopy (TEM), potentiometric titration, diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), inductively coupled plasma optical emission spectrometry (ICP-OES), X-ray photoelectron spectrometry (XPS), and dynamic light scattering (DLS). The sulfonic acid functionalized particles were used to catalyze the hydrolysis of sucrose at 80° and starch at 130°, showing a higher activity per acid site than the traditional solid acid catalyst Amberlyst-15, and comparing well against results reported in the literature for sulfonic acid functionalized mesoporous silicas. In sucrose catalysis reactions, the phosphonic-sulfonic nanoparticles (PSNPs) were seen to be incompletely recovered by an external magnetic field, while the carboxylic-sulfonic nanoparticles (CSNPs) showed a trend of increasing activity over the first four recycle runs. Between the two sulfonic ligands, the phosphonates produced a more tightly packed monolayer, which corresponded to a higher sulfonic acid loading, lower agglomeration, lower recoverability through application of an external magnetic field, and higher activity per acid site for the hydrolysis of starch. Functionalizations with 11-aminoundecanoic acid resulted in some amine groups binding to the surfaces of iron oxide nanoparticles. This amine binding is commonly ignored in iron oxide

  8. Formulations for iron oxides dissolution

    DOEpatents

    Horwitz, Earl P.; Chiarizia, Renato

    1992-01-01

    A mixture of a di- or polyphosphonic acid and a reductant wherein each is present in a sufficient amount to provide a synergistic effect with respect to the dissolution of metal oxides and optionally containing corrosion inhibitors and pH adjusting agents.

  9. Nitric oxide and plant iron homeostasis.

    PubMed

    Buet, Agustina; Simontacchi, Marcela

    2015-03-01

    Like all living organisms, plants demand iron (Fe) for important biochemical and metabolic processes. Internal imbalances, as a consequence of insufficient or excess Fe in the environment, lead to growth restriction and affect crop yield. Knowledge of signals and factors affecting each step in Fe uptake from the soil and distribution (long-distance transport, remobilization from old to young leaves, and storage in seeds) is necessary to improve our understanding of plant mineral nutrition. In this context, the role of nitric oxide (NO) is discussed as a key player in maintaining Fe homeostasis through its cross talk with hormones, ferritin, and frataxin and the ability to form nitrosyl-iron complexes.

  10. Starch vermicelli template for synthesis of magnetic iron oxide nanoclusters

    NASA Astrophysics Data System (ADS)

    Chairam, Sanoe; Somsook, Ekasith

    A novel method for fabricating magnetic iron oxide nanoparticles was achieved by using transparent vermicelli template as a new stabilizing material. The morphology of the as-prepared magnetic iron oxide deposited on the surface of vermicelli was observed as nanoclusters. The magnetization of the magnetic iron oxide nanoparticles at room temperature was decreased after carbonization at 200 °C. Therefore the thermal decomposition of iron oxide nanoparticles stabilized by starch vermicelli template yielded iron oxide/carbon nanocomposites with the soft magnetic behavior which are useful for biomedical applications.

  11. Optical properties of iron oxides

    NASA Astrophysics Data System (ADS)

    Musfeldt, Janice

    2012-02-01

    Magnetoelectric coupling in materials like multiferroics, dilute magnetic semiconductors, and topological insulators has attracted a great deal of attention, although most work has been done in the static limit. Optical spectroscopy offers a way to investigate the dynamics of charge-spin coupling, an area where there has been much less effort. Using these techniques, we discovered that charge fluctuation in LuFe2O4, the prototypical charge ordered multiferroic, has an onset well below the charge ordering transition, supporting the ``order by fluctuation'' mechanism for the development of charge order superstructure. Bragg splitting and large magneto-optical contrast suggest a low temperature monoclinic distortion that can be driven by both temperature and magnetic field. At the same time, dramatic splitting of the LuO2 layer phonon mode is attributed to charge-rich/poor proximity effects, and its temperature dependence reveals the antipolar nature of the W layer pattern. Using optical techniques, we also discovered that α-Fe2O3, a chemically-similar parent compound and one of the world's oldest and most iconic antiferromagnetic materials, appears more red in applied magnetic field than in zero field conditions. This effect is driven by a field-induced reorientation of magnetic order. The oscillator strength lost in the color band is partially transferred to the magnon side band, a process that also reveals a new exciton pattern induced by the modified exchange coupling. Analysis of the exciton pattern exposes C2/c monoclinic symmetry in the high field phase of hematite. Taken together, these findings advance our understanding of iron-based materials under extreme conditions. [4pt] Collaborators include: X. S. Xu, P. Chen, Q. -C. Sun, T. V. Brinzari (Tennessee); S. McGill (NHMFL); J. De Groot, M. Angst, R. P. Hermann (Julich); A. D. Christianson, B. C. Sales, D. Mandrus (ORNL); A. P. Litvinchuk (Houston); J. -W. Kim (Ames); Z. Islam (Argonne); N. Lee, S. -W. Cheong

  12. Oxidation Potentials in Iron and Steel Making

    NASA Astrophysics Data System (ADS)

    Matousek, J. W.

    2013-11-01

    The state of oxidation of a pyrometallurgical process given by the partial pressure of oxygen and the temperature (the oxidation potential) is one of the important properties monitored and controlled in the smelting and refining of iron and the nonferrous metals. Solid electrolyte sensors based on ZrO2 and a reference electrode such as Cr/Cr2O3 to measure the oxygen pressure found early application in the steel industry, followed soon after in copper, nickel, lead, and zinc smelting. Similar devices are installed in automobile postcombustion/exhaust trains as part of emission control systems. The current discussion reviews this technology as applied in the primary steps of iron and steel making and refining.

  13. Method for preparing hydrous iron oxide gels and spherules

    DOEpatents

    Collins, Jack L.; Lauf, Robert J.; Anderson, Kimberly K.

    2003-07-29

    The present invention is directed to methods for preparing hydrous iron oxide spherules, hydrous iron oxide gels such as gel slabs, films, capillary and electrophoresis gels, iron monohydrogen phosphate spherules, hydrous iron oxide spherules having suspendable particles homogeneously embedded within to form composite sorbents and catalysts, iron monohydrogen phosphate spherules having suspendable particles of at least one different sorbent homogeneously embedded within to form a composite sorbent, iron oxide spherules having suspendable particles homogeneously embedded within to form a composite of hydrous iron oxide fiber materials, iron oxide fiber materials, hydrous iron oxide fiber materials having suspendable particles homogeneously embedded within to form a composite, iron oxide fiber materials having suspendable particles homogeneously embedded within to form a composite, dielectric spherules of barium, strontium, and lead ferrites and mixtures thereof, and composite catalytic spherules of barium or strontium ferrite embedded with oxides of Mg, Zn, Pb, Ce and mixtures thereof. These variations of hydrous iron oxide spherules and gel forms prepared by the gel-sphere, internal gelation process offer more useful forms of inorganic ion exchangers, catalysts, getters, dielectrics, and ceramics.

  14. Planktonic marine iron oxidizers drive iron mineralization under low-oxygen conditions.

    PubMed

    Field, E K; Kato, S; Findlay, A J; MacDonald, D J; Chiu, B K; Luther, G W; Chan, C S

    2016-09-01

    Observations of modern microbes have led to several hypotheses on how microbes precipitated the extensive iron formations in the geologic record, but we have yet to resolve the exact microbial contributions. An initial hypothesis was that cyanobacteria produced oxygen which oxidized iron abiotically; however, in modern environments such as microbial mats, where Fe(II) and O2 coexist, we commonly find microaerophilic chemolithotrophic iron-oxidizing bacteria producing Fe(III) oxyhydroxides. This suggests that such iron oxidizers could have inhabited niches in ancient coastal oceans where Fe(II) and O2 coexisted, and therefore contributed to banded iron formations (BIFs) and other ferruginous deposits. However, there is currently little evidence for planktonic marine iron oxidizers in modern analogs. Here, we demonstrate successful cultivation of planktonic microaerophilic iron-oxidizing Zetaproteobacteria from the Chesapeake Bay during seasonal stratification. Iron oxidizers were associated with low oxygen concentrations and active iron redox cycling in the oxic-anoxic transition zone (<3 μm O2 , <0.2 μm H2 S). While cyanobacteria were also detected in this transition zone, oxygen concentrations were too low to support significant rates of abiotic iron oxidation. Cyanobacteria may be providing oxygen for microaerophilic iron oxidation through a symbiotic relationship; at high Fe(II) levels, cyanobacteria would gain protection against Fe(II) toxicity. A Zetaproteobacteria isolate from this site oxidized iron at rates sufficient to account for deposition of geologic iron formations. In sum, our results suggest that once oxygenic photosynthesis evolved, microaerophilic chemolithotrophic iron oxidizers were likely important drivers of iron mineralization in ancient oceans. PMID:27384464

  15. Nitric oxide and plant iron homeostasis.

    PubMed

    Buet, Agustina; Simontacchi, Marcela

    2015-03-01

    Like all living organisms, plants demand iron (Fe) for important biochemical and metabolic processes. Internal imbalances, as a consequence of insufficient or excess Fe in the environment, lead to growth restriction and affect crop yield. Knowledge of signals and factors affecting each step in Fe uptake from the soil and distribution (long-distance transport, remobilization from old to young leaves, and storage in seeds) is necessary to improve our understanding of plant mineral nutrition. In this context, the role of nitric oxide (NO) is discussed as a key player in maintaining Fe homeostasis through its cross talk with hormones, ferritin, and frataxin and the ability to form nitrosyl-iron complexes. PMID:25612116

  16. Water clustering on nanostructured iron oxide films

    NASA Astrophysics Data System (ADS)

    Merte, Lindsay R.; Bechstein, Ralf; Peng, Guowen; Rieboldt, Felix; Farberow, Carrie A.; Zeuthen, Helene; Knudsen, Jan; Lægsgaard, Erik; Wendt, Stefan; Mavrikakis, Manos; Besenbacher, Flemming

    2014-06-01

    The adhesion of water to solid surfaces is characterized by the tendency to balance competing molecule-molecule and molecule-surface interactions. Hydroxyl groups form strong hydrogen bonds to water molecules and are known to substantially influence the wetting behaviour of oxide surfaces, but it is not well-understood how these hydroxyl groups and their distribution on a surface affect the molecular-scale structure at the interface. Here we report a study of water clustering on a moiré-structured iron oxide thin film with a controlled density of hydroxyl groups. While large amorphous monolayer islands form on the bare film, the hydroxylated iron oxide film acts as a hydrophilic nanotemplate, causing the formation of a regular array of ice-like hexameric nanoclusters. The formation of this ordered phase is localized at the nanometre scale; with increasing water coverage, ordered and amorphous water are found to coexist at adjacent hydroxylated and hydroxyl-free domains of the moiré structure.

  17. Water Clustering on Nanostructured Iron Oxide Films

    SciTech Connect

    Merte, L. R.; Bechstein, Ralf; Peng, Guowen; Rieboldt, Felix; Farberow, Carrie A.; Zeuthen, Helene; Knudsen, Jan; Laegsgaard, E.; Wendt, Stefen; Mavrikakis, Manos; Besenbacher, Fleming

    2014-06-30

    The adhesion of water to solid surfaces is characterized by the tendency to balance competing molecule–molecule and molecule–surface interactions. Hydroxyl groups form strong hydrogen bonds to water molecules and are known to substantially influence the wetting behaviour of oxide surfaces, but it is not well-understood how these hydroxyl groups and their distribution on a surface affect the molecular-scale structure at the interface. Here we report a study of water clustering on a moire´-structured iron oxide thin film with a controlled density of hydroxyl groups. While large amorphous monolayer islands form on the are film, the hydroxylated iron oxide film acts as a hydrophilic nanotemplate, causing the formation of a regular array of ice-like hexameric nanoclusters. The formation of this ordered phase is localized at the nanometre scale; with increasing water coverage, ordered and amorphous water are found to coexist at adjacent hydroxylated and hydroxyl-free domains of the moire´ structure.

  18. Phase Formation Behavior in Ultrathin Iron Oxide.

    PubMed

    Jõgi, Indrek; Jacobsson, T Jesper; Fondell, Mattis; Wätjen, Timo; Carlsson, Jan-Otto; Boman, Mats; Edvinsson, Tomas

    2015-11-17

    Nanostructured iron oxides, and especially hematite, are interesting for a wide range of applications ranging from gas sensors to renewable solar hydrogen production. A promising method for deposition of low-dimensional films is atomic layer deposition (ALD). Although a potent technique, ALD of ultrathin films is critically sensitive to the substrate and temperature conditions where initial formation of islands and crystallites influences the properties of the films. In this work, deposition at the border of the ALD window forming a hybrid ALD/pulsed CVD (pCVD) deposition is utilized to obtain a deposition less sensitive to the substrate. A thorough analysis of iron oxide phases formation on two different substrates, Si(100) and SiO2, was performed. Films between 3 and 50 nm were deposited and analyzed with diffraction techniques, high-resolution Raman spectroscopy, and optical spectroscopy. Below 10 nm nominal film thickness, island formation and phase dependent particle crystallization impose constraints for deposition of phase pure iron oxides on non-lattice-matching substrates. Films between 10 and 20 nm thickness on SiO2 could effectively be recrystallized into hematite whereas for the corresponding films on Si(100), no recrystallization occurred. For films thicker than 20 nm, phase pure hematite can be formed directly with ALD/pCVD with very low influence of the substrate on either Si or SiO2. For more lattice matched substrates such as SnO2:F, Raman spectroscopy indicated formation of the hematite phase already for films with 3 nm nominal thickness and clearly for 6 nm films. Analysis of the optical properties corroborated the analysis and showed a quantum confined blue-shift of the absorption edge for the thinnest films. PMID:26506091

  19. Suspension Hydrogen Reduction of Iron Oxide Concentrates

    SciTech Connect

    H.Y. Sohn

    2008-03-31

    The objective of the project is to develop a new ironmaking technology based on hydrogen and fine iron oxide concentrates in a suspension reduction process. The ultimate objective of the new technology is to replace the blast furnace and to drastically reduce CO2 emissions in the steel industry. The goals of this phase of development are; the performance of detailed material and energy balances, thermochemical and equilibrium calculations for sulfur and phosphorus impurities, the determination of the complete kinetics of hydrogen reduction and bench-scale testing of the suspension reduction process using a large laboratory flash reactor.

  20. Magnetic iron oxide nanoparticles for biomedical applications.

    PubMed

    Laurent, Sophie; Bridot, Jean-Luc; Elst, Luce Vander; Muller, Robert N

    2010-03-01

    Due to their high magnetization, superparamagnetic iron oxide nanoparticles induce an important decrease in the transverse relaxation of water protons and are, therefore, very efficient negative MRI contrast agents. The knowledge and control of the chemical and physical characteristics of nanoparticles are of great importance. The choice of the synthesis method (microemulsions, sol-gel synthesis, laser pyrolysis, sonochemical synthesis or coprecipitation) determines the magnetic nanoparticle's size and shape, as well as its size distribution and surface chemistry. Nanoparticles can be used for numerous in vivo applications, such as MRI contrast enhancement and hyperthermia drug delivery. New developments focus on targeting through molecular imaging and cell tracking. PMID:21426176

  1. Modified iron oxide nanomaterials: Functionalization and application

    NASA Astrophysics Data System (ADS)

    Bagheri, Samira; Julkapli, Nurhidayatullaili Muhd

    2016-10-01

    Iron oxide magnetic nanoparticles have aroused the interest of researchers of materials' chemistry due to its exceptional properties such as decent magnetic, electric, catalytic, biocompatibility, and low toxicity. However, these magnetic nanoparticles are predisposed towards aggregation and forming larger particles, due to its strong anisotropic dipolar interactions, particularly in the aqueous phase, consequently depriving them of dispersibility and particular properties, ultimately degrading their performance. Hence, this review focuses on modified magnetic nanoparticles that are stable, easily synthesized, possess a high surface area and could be facile-separated via magnetic forces, and are of low toxicity and costs for applications such as catalyst/catalyst support, food security, biomedical, and pollutant remediation.

  2. The Sulfide Capacity of Iron Oxide-Rich Slags

    NASA Astrophysics Data System (ADS)

    Motlagh, M.

    1988-03-01

    The relationship between the sulfide capacity of slags rich in iron oxide and the sulfur partition ratio between the metal and slag is strongly related to the slag's iron oxide concentration. For slags containing little or no lime, this relationship is linear for a constant concentration of iron oxide in the slag. The effect of silica on changes in the sulfide capacity of slags rich in iron oxide is similar to that of basic steel-making slags, particularly at low activity of silica in slag.

  3. Mineral resource of the month: iron oxide pigments

    USGS Publications Warehouse

    ,

    2008-01-01

    The article discusses iron oxide pigments, which have been used as colorants since human began painting as they resist color change due to sunlight exposure, have good chemical resistance and are stable under normal ambient conditions. Cyprus, Italy and Spain are among the countries that are known for the production of iron oxide pigments. Granular forms of iron oxides and nano-sized materials are cited as developments in the synthetic iron oxide pigment industry which are being used in computer disk drives and nuclear magnetic resonance imaging.

  4. A Diatom Ferritin Optimized for Iron Oxidation but Not Iron Storage*

    PubMed Central

    Pfaffen, Stephanie; Bradley, Justin M.; Abdulqadir, Raz; Firme, Marlo R.; Moore, Geoffrey R.; Le Brun, Nick E.; Murphy, Michael E. P.

    2015-01-01

    Ferritin from the marine pennate diatom Pseudo-nitzschia multiseries (PmFTN) plays a key role in sustaining growth in iron-limited ocean environments. The di-iron catalytic ferroxidase center of PmFTN (sites A and B) has a nearby third iron site (site C) in an arrangement typically observed in prokaryotic ferritins. Here we demonstrate that Glu-44, a site C ligand, and Glu-130, a residue that bridges iron bound at sites B and C, limit the rate of post-oxidation reorganization of iron coordination and the rate at which Fe3+ exits the ferroxidase center for storage within the mineral core. The latter, in particular, severely limits the overall rate of iron mineralization. Thus, the diatom ferritin is optimized for initial Fe2+ oxidation but not for mineralization, pointing to a role for this protein in buffering iron availability and facilitating iron-sparing rather than only long-term iron storage. PMID:26396187

  5. Insight into the evolution of the iron oxidation pathways.

    PubMed

    Ilbert, Marianne; Bonnefoy, Violaine

    2013-02-01

    Iron is a ubiquitous element in the universe. Ferrous iron (Fe(II)) was abundant in the primordial ocean until the oxygenation of the Earth's atmosphere led to its widespread oxidation and precipitation. This change of iron bioavailability likely put selective pressure on the evolution of life. This element is essential to most extant life forms and is an important cofactor in many redox-active proteins involved in a number of vital pathways. In addition, iron plays a central role in many environments as an energy source for some microorganisms. This review is focused on Fe(II) oxidation. The fact that the ability to oxidize Fe(II) is widely distributed in Bacteria and Archaea and in a number of quite different biotopes suggests that the dissimilatory Fe(II) oxidation is an ancient energy metabolism. Based on what is known today about Fe(II) oxidation pathways, we propose that they arose independently more than once in evolution and evolved convergently. The iron paleochemistry, the phylogeny, the physiology of the iron oxidizers, and the nature of the cofactors of the redox proteins involved in these pathways suggest a possible scenario for the timescale in which each type of Fe(II) oxidation pathways evolved. The nitrate dependent anoxic iron oxidizers are likely the most ancient iron oxidizers. We suggest that the phototrophic anoxic iron oxidizers arose in surface waters after the Archaea/Bacteria-split but before the Great Oxidation Event. The neutrophilic oxic iron oxidizers possibly appeared in microaerobic marine environments prior to the Great Oxidation Event while the acidophilic ones emerged likely after the advent of atmospheric O(2). This article is part of a Special Issue entitled: The evolutionary aspects of bioenergetic systems. PMID:23044392

  6. Superparamagnetic iron oxide nanoparticles with variable size and an iron oxidation state as prospective imaging agents.

    PubMed

    Kucheryavy, Pavel; He, Jibao; John, Vijay T; Maharjan, Pawan; Spinu, Leonard; Goloverda, Galina Z; Kolesnichenko, Vladimir L

    2013-01-15

    Magnetite nanoparticles in the size range of 3.2-7.5 nm were synthesized in high yields under variable reaction conditions using high-temperature hydrolysis of the precursor iron(II) and iron(III) alkoxides in diethylene glycol solution. The average sizes of the particles were adjusted by changing the reaction temperature and time and by using a sequential growth technique. To obtain γ-iron(III) oxide particles in the same range of sizes, magnetite particles were oxidized with dry oxygen in diethylene glycol at room temperature. The products were characterized by DLS, TEM, X-ray powder diffractometry, TGA, chemical analysis, and magnetic measurements. NMR r(1) and r(2) relaxivity measurements in water and diethylene glycol (for OH and CH(2) protons) have shown a decrease in the r(2)/r(1) ratio with the particle size reduction, which correlates with the results of magnetic measurements on magnetite nanoparticles. Saturation magnetization of the oxidized particles was found to be 20% lower than that for Fe(3)O(4) with the same particle size, but their r(1) relaxivities are similar. Because the oxidation of magnetite is spontaneous under ambient conditions, it was important to learn that the oxidation product has no disadvantages as compared to its precursor and therefore may be a better prospective imaging agent because of its chemical stability.

  7. Thermochemistry of iron manganese oxide spinels

    SciTech Connect

    Guillemet-Fritsch, Sophie; Navrotsky, Alexandra . E-mail: anavrotsky@ucdavis.edu; Tailhades, Philippe; Coradin, Herve; Wang Miaojun

    2005-01-15

    Oxide melt solution calorimetry has been performed on iron manganese oxide spinels prepared at high temperature. The enthalpy of formation of (Mn{sub x}Fe{sub 1-x}){sub 3}O{sub 4} at 298K from the oxides, tetragonal Mn{sub 3}O{sub 4} (hausmannite) and cubic Fe{sub 3}O{sub 4} (magnetite), is negative from x=0 to x=0.67 and becomes slightly positive for 0.670.6) spinels of intermediate compositions. The enthalpies of formation are discussed in terms of three factors: oxidation-reduction relative to the end-members, cation distribution, and tetragonality. A combination of measured enthalpies and Gibbs free energies of formation in the literature provides entropies of mixing. {delta}S{sub mix}, consistent with a cation distribution in which all trivalent manganese is octahedral and all other ions are randomly distributed for x>0.5, but the entropy of mixing appears to be smaller than these predicted values for x<0.4.

  8. Battles with iron: manganese in oxidative stress protection.

    PubMed

    Aguirre, J Dafhne; Culotta, Valeria C

    2012-04-20

    The redox-active metal manganese plays a key role in cellular adaptation to oxidative stress. As a cofactor for manganese superoxide dismutase or through formation of non-proteinaceous manganese antioxidants, this metal can combat oxidative damage without deleterious side effects of Fenton chemistry. In either case, the antioxidant properties of manganese are vulnerable to iron. Cellular pools of iron can outcompete manganese for binding to manganese superoxide dismutase, and through Fenton chemistry, iron may counteract the benefits of non-proteinaceous manganese antioxidants. In this minireview, we highlight ways in which cells maximize the efficacy of manganese as an antioxidant in the midst of pro-oxidant iron.

  9. Comparison of iron-catalyzed DNA and lipid oxidation.

    PubMed

    Djuric, Z; Potter, D W; Taffe, B G; Strasburg, G M

    2001-01-01

    Lipid and DNA oxidation catalyzed by iron(II) were compared in HEPES and phosphate buffers. Lipid peroxidation was examined in a sensitive liposome system constructed with a fluorescent probe that allowed us to examine the effects of both low and high iron concentrations. With liposomes made from synthetic 1-stearoyl-2-linoleoyl-sn-glycero-3-phosphocholine or from rat liver microsomal lipid, lipid peroxidation increased with iron concentration up to the range of 10--20 microM iron(II), but then rates decreased with further increases in iron concentration. This may be due to the limited amount of lipid peroxides available in liposomes for oxidation of iron(II) to generate equimolar iron(III), which is thought to be important for the initation of lipid peroxidation. Addition of hydrogen peroxide to incubations with 1--10 microM iron(II) decreased rates of lipid peroxidation, whereas addition of hydrogen peroxide to incubations with higher iron concentrations increased rates of lipid peroxidation. Thus, in this liposome system, sufficient peroxide from either within the lipid or from exogenous sources must be present to generate equimolar iron(II) and iron(III). With iron-catalyzed DNA oxidation, hydrogen peroxide always stimulated product formation. Phosphate buffer, which chelates iron but still allows for generation of hydroxyl radicals, inhibited lipid peroxidation but not DNA oxidation. HEPES buffer, which scavenges hydroxyl radicals, inhibited DNA oxidation, whereas lipid peroxidation was unaffected since presumably iron(II) and iron(III) were still available for reaction with liposomes in HEPES buffer. PMID:11284053

  10. TRACE ELEMENT BINDING DURING STRUCTURAL TRANSFORMATION IN IRON OXIDES

    EPA Science Inventory

    Iron (hydr)oxides often control the mobility of inorganic contaminants in soils and sediments. A poorly ordered form of ferrihydrite is commonly produced during rapid oxidation of ferrous iron at sharp redox fronts encountered during discharge of anoxic/suboxic waters into terre...

  11. Ecological succession among iron-oxidizing bacteria

    PubMed Central

    Fleming, Emily J; Cetinić, Ivona; Chan, Clara S; Whitney King, D; Emerson, David

    2014-01-01

    Despite over 125 years of study, the factors that dictate species dominance in neutrophilic iron-oxidizing bacterial (FeOB) communities remain unknown. In a freshwater wetland, we documented a clear ecological succession coupled with niche separation between the helical stalk-forming Gallionellales (for example, Gallionella ferruginea) and tubular sheath-forming Leptothrix ochracea. Changes in the iron-seep community were documented using microscopy and cultivation-independent methods. Quantification of Fe-oxyhydroxide morphotypes by light microscopy was coupled with species-specific fluorescent in situ hybridization (FISH) probes using a protocol that minimized background fluorescence caused by the Fe-oxyhydroxides. Together with scanning electron microscopy, these techniques all indicated that Gallionellales dominated during early spring, with L. ochracea becoming more abundant for the remainder of the year. Analysis of tagged pyrosequencing reads of the small subunit ribosomal RNA gene (SSU rRNA) collected during seasonal progression supported a clear Gallionellales to L. ochracea transition, and community structure grouped according to observed dominant FeOB forms. Axis of redundancy analysis of physicochemical parameters collected from iron mats during the season, plotted with FeOB abundance, corroborated several field and microscopy-based observations and uncovered several unanticipated relationships. On the basis of these relationships, we conclude that the ecological niche of the stalk-forming Gallionellales is in waters with low organic carbon and steep redoxclines, and the sheath-forming L. ochracea is abundant in waters that contain high concentrations of complex organic carbon, high Fe and Mn content and gentle redoxclines. Finally, these findings identify a largely unexplored relationship between FeOB and organic carbon. PMID:24225888

  12. Microbially Induced Iron Oxidation: What, Where, How

    SciTech Connect

    SCHIERMEYER,ELISA M.; PROVENCIO,PAULA P.; NORTHUP,DIANA E.

    2000-08-15

    From the results of the different bacterial cells seen, it is fairly certain that Gallionella is present because of the bean-shaped cells and twisted stalks found with the TEM. The authors cannot confirm, though, what other iron-oxidizing genera exist in the tubes, since the media was only preferential and not one that isolated a specific genus of bacteria. Based on the environment in which they live and the source of the water, they believe their cultures contain Gallionella, Leptothrix, and possibly Crenothrix and Sphaerotilus. They believe the genus Leptothrix rather than Sphaerotilus exist in the tubes because the water source was fresh, unlike the polluted water in which Sphaerotilus are usually found. The TEM preparations worked well. The cryogenic method rapidly froze the cells in place and allowed them to view their morphology. The FAA method, as stated previously, was the best of the three methods because it gave the best contrast. The gluteraldehyde samples did not come out as well. It is possible that the gluteraldehyde the authors prepared was still too concentrated and did not mix well. Although these bacteria were collected from springs and then cultured in an environment containing a presumably pure iron-bearing metal, it seems the tube already containing Manganese Gradient Medium could be used with a piece of metal containing these bacteria. A small piece of corroding metal could then be inserted into the test tube and cultured to study the bacteria.

  13. Oxidation inhibits iron-induced blood coagulation.

    PubMed

    Pretorius, Etheresia; Bester, Janette; Vermeulen, Natasha; Lipinski, Boguslaw

    2013-01-01

    Blood coagulation under physiological conditions is activated by thrombin, which converts soluble plasma fibrinogen (FBG) into an insoluble clot. The structure of the enzymatically-generated clot is very characteristic being composed of thick fibrin fibers susceptible to the fibrinolytic degradation. However, in chronic degenerative diseases, such as atherosclerosis, diabetes mellitus, cancer, and neurological disorders, fibrin clots are very different forming dense matted deposits (DMD) that are not effectively removed and thus create a condition known as thrombosis. We have recently shown that trivalent iron (ferric ions) generates hydroxyl radicals, which subsequently convert FBG into abnormal fibrin clots in the form of DMDs. A characteristic feature of DMDs is their remarkable and permanent resistance to the enzymatic degradation. Therefore, in order to prevent thrombotic incidences in the degenerative diseases it is essential to inhibit the iron-induced generation of hydroxyl radicals. This can be achieved by the pretreatment with a direct free radical scavenger (e.g. salicylate), and as shown in this paper by the treatment with oxidizing agents such as hydrogen peroxide, methylene blue, and sodium selenite. Although the actual mechanism of this phenomenon is not yet known, it is possible that hydroxyl radicals are neutralized by their conversion to the molecular oxygen and water, thus inhibiting the formation of dense matted fibrin deposits in human blood.

  14. Iron oxidation and its impact on MR behavior

    NASA Astrophysics Data System (ADS)

    Sunkara, S. R.; Root, T. W.; Ulicny, J. C.; Klingenberg, D. J.

    2009-02-01

    The oxidation of particles in MR fluids and its impact on rheology are investigated. The oxidation of iron spheres in an aliphatic oil follows a linear growth law, suggesting that the oxide forms a nonadherent layer. The magnetic field-induced yield stress decreases with increasing extent of oxidation. The rheological behavior is consistent with that predicted using a core-shell model.

  15. Multifunctional iron oxide nanoparticles for biomedical applications

    NASA Astrophysics Data System (ADS)

    Bloemen, M.; Denis, C.; Van Stappen, T.; De Meester, L.; Geukens, N.; Gils, A.; Verbiest, T.

    2015-03-01

    Multifunctional nanoparticles have attracted a lot of attention since they can combine interesting properties like magnetism, fluorescence or plasmonic effects. As a core material, iron oxide nanoparticles have been the subject of intensive research. These cost-effective and non-toxic particles are used nowadays in many applications. We developed a heterobifunctional PEG ligand that can be used to introduce functional groups (carboxylic acids) onto the surface of the NP. Via click chemistry, a siloxane functionality was added to this ligand, for a subsequent covalent ligand exchange reaction. The functionalized nanoparticles have an excellent colloidal stability in complex environments like buffers and serum or plasma. Antibodies were coupled to the introduced carboxylic acids and these NP-antibody bioconjugates were brought into contact with Legionella bacteria for magnetic separation experiments.

  16. Multiple hearth furnace for reducing iron oxide

    DOEpatents

    Brandon, Mark M.; True, Bradford G.

    2012-03-13

    A multiple moving hearth furnace (10) having a furnace housing (11) with at least two moving hearths (20) positioned laterally within the furnace housing, the hearths moving in opposite directions and each moving hearth (20) capable of being charged with at least one layer of iron oxide and carbon bearing material at one end, and being capable of discharging reduced material at the other end. A heat insulating partition (92) is positioned between adjacent moving hearths of at least portions of the conversion zones (13), and is capable of communicating gases between the atmospheres of the conversion zones of adjacent moving hearths. A drying/preheat zone (12), a conversion zone (13), and optionally a cooling zone (15) are sequentially positioned along each moving hearth (30) in the furnace housing (11).

  17. Washing effect on superparamagnetic iron oxide nanoparticles

    PubMed Central

    Mireles, Laura-Karina; Sacher, Edward; Yahia, L’Hocine; Laurent, Sophie; Stanicki, Dimitri

    2016-01-01

    Much recent research on nanoparticles has occurred in the biomedical area, particularly in the area of superparamagnetic iron oxide nanoparticles (SPIONs); one such area of research is in their use as magnetically directed prodrugs. It has been reported that nanoscale materials exhibit properties different from those of materials in bulk or on a macro scale [1]. Further, an understanding of the batch-to-batch reproducibility and uniformity of the SPION surface is essential to ensure safe biological applications, as noted in the accompanying article [2], because the surface is the first layer that affects the biological response of the human body. Here, we consider a comparison of the surface chemistries of a batch of SPIONs, before and after the supposedly gentle process of dialysis in water. PMID:27141527

  18. Rheological Properties of Iron Oxide Based Ferrofluids

    NASA Astrophysics Data System (ADS)

    Devi, M.; Mohanta, D.

    2009-06-01

    In the present work, we report synthesis and magneto-viscous properties of cationic and anionic surfactant coated, iron oxide nanoparticles based ferrofluids. Structural and morphological aspects are revealed by x-ray diffraction (XRD) and transmission electron microscopy (TEM) studies. We compare the rheological/magneto-viscous properties of different ferrofluids for various shear rates (2-450 sec-1) and applied magnetic fields (0-100 gauss). In the absence of a magnetic field, and under no shear case, the ferrofluid prepared with TMAH coated particle is found to be 12% more viscous compared to its counterpart. The rheological properties are governed by non-Newtonian features, and for a definite shear rate, viscosity of a given ferrofluid is found to be strongly dependent on the applied magnetic field as well as nature of the surfactant.

  19. Gold supported iron oxide-hydroxide derived from iron ore tailings for CO oxidation

    NASA Astrophysics Data System (ADS)

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

    2009-04-01

    Iron ore tailing, a waste material of iron ore industry, has been used to prepare iron oxide-hydroxide support for anchoring nano-gold particles. FeOOH was prepared from iron chloride solution obtained from acid digestion of iron ore tailing. Precipitation deposition method was used to prepare Au supported FeOOH. The samples were characterized by XRD, TEM, TG-DTA and FTIR. The XRD studies have confirmed the FeOOH phase and the TEM studies reveal the anchoring of gold particles on FeOOH whose size is about 5 nm. FTIR spectra showed the vibration mode of metal-oxygen bond and the presence of hydroxyl group in FeOOH and Au/FeOOH. TG-DTA results confirmed dehydration of FeOOH and the process is retarded by the presence of Au particles. The catalytic conversion of carbon monoxide by Au/FeOOH was around 55% but the catalyst became inactive after pretreatment at 300 °C in presence of oxygen which led to agglomeration of Au particles and removal of hydroxyl groups from the surface of FeOOH.

  20. Controlling barrier penetration via exothermic iron oxidation.

    PubMed

    Wood, Daniel G; Brown, Marc B; Jones, Stuart A

    2011-02-14

    Exothermic iron oxidation is an elegant means to generate heat, with the potential to modulate barrier penetration if reaction kinetics can be controlled. This aim of this study was to gain a fundamental understanding of how these temperature change kinetics influenced barrier diffusion rate. Lidocaine transport through a hydrophilic carboxymethyl cellulose (CMC) gel was compared using two rapid iron oxidation reactions initiated by water (ExoRap(50), T(max)-47.7 ± 0.6 °C, t(max)-3.3 ± 0.6 min, ExoRap(60), T(max)-60.4 ± 0.3 °C, t(max)-9.3 ± 0.6 min) and a slower reaction initiated by oxygen (ExoSl(45)T(max)-ca. 44 °C, t(max) ca. 240 min). Temperature change induced by the oxygen initiated reaction (ExoSl(45)) was almost double those initiated by water (over 4h), but lidocaine diffusion was approximately 4 times higher for the latter (ExoRap(50), 555.61 ± 22.04 μg/cm(2)/h; ExoRap(60), 663.1 ± 50.95 μg/cm(2)/h; compared to ExoSl(45), 159.36 ± 29.44 μg/cm(2)/h). The large influence of temperature change kinetics on lidocaine diffusion suggested that transport was heavily dependent on temperature induced structural changes of the barrier. CMC, like many polymers adsorbs more water when exposed to moderate increases in temperature and this appeared to be a critical determinant of lidocaine barrier diffusion rate.

  1. Nitrate-dependent iron oxidation limits iron transport in anoxic ocean regions

    NASA Astrophysics Data System (ADS)

    Scholz, Florian; Löscher, Carolin R.; Fiskal, Annika; Sommer, Stefan; Hensen, Christian; Lomnitz, Ulrike; Wuttig, Kathrin; Göttlicher, Jörg; Kossel, Elke; Steininger, Ralph; Canfield, Donald E.

    2016-11-01

    Iron is an essential element for life on Earth and limits primary production in large parts of the ocean. Oxygen-free continental margin sediments represent an important source of bioavailable iron to the ocean, yet little of the iron released from the seabed reaches the productive sea surface. Even in the anoxic water of oxygen minimum zones, where iron solubility should be enhanced, most of the iron is rapidly re-precipitated. To constrain the mechanism(s) of iron removal in anoxic ocean regions we explored the sediment and water in the oxygen minimum zone off Peru. During our sampling campaign the water column featured two distinct redox boundaries separating oxic from nitrate-reducing (i.e., nitrogenous) water and nitrogenous from weakly sulfidic water. The sulfidic water mass in contact with the shelf sediment contained elevated iron concentrations >300 nM. At the boundary between sulfidic and nitrogenous conditions, iron concentrations dropped sharply to <20 nM coincident with a maximum in particulate iron concentration. Within the iron gradient, we found an increased expression of the key functional marker gene for nitrate reduction (narG). Part of this upregulation was related to the activity of known iron-oxidizing bacteria. Collectively, our data suggest that iron oxidation and removal is induced by nitrate-reducing microbes, either enzymatically through anaerobic iron oxidation or by providing nitrite for an abiotic reaction. Given the important role that iron plays in nitrogen fixation, photosynthesis and respiration, nitrate-dependent iron oxidation likely represents a key-link between the marine biogeochemical cycles of nitrogen, oxygen and carbon.

  2. Reactive oxygen species-related activities of nano-iron metal and nano-iron oxides.

    PubMed

    Wu, Haohao; Yin, Jun-Jie; Wamer, Wayne G; Zeng, Mingyong; Lo, Y Martin

    2014-03-01

    Nano-iron metal and nano-iron oxides are among the most widely used engineered and naturally occurring nanostructures, and the increasing incidence of biological exposure to these nanostructures has raised concerns about their biotoxicity. Reactive oxygen species (ROS)-induced oxidative stress is one of the most accepted toxic mechanisms and, in the past decades, considerable efforts have been made to investigate the ROS-related activities of iron nanostructures. In this review, we summarize activities of nano-iron metal and nano-iron oxides in ROS-related redox processes, addressing in detail the known homogeneous and heterogeneous redox mechanisms involved in these processes, intrinsic ROS-related properties of iron nanostructures (chemical composition, particle size, and crystalline phase), and ROS-related bio-microenvironmental factors, including physiological pH and buffers, biogenic reducing agents, and other organic substances.

  3. Surface Engineering of Core/Shell Iron/Iron Oxide Nanoparticles from Microemulsions for Hyperthermia

    PubMed Central

    Zhang, Guandong; Liao, Yifeng; Baker, Ian

    2011-01-01

    This paper describes the synthesis and surface engineering of core/shell-type iron/iron oxide nanoparticles for magnetic hyperthermia cancer therapy. Iron/iron oxide nanoparticles were synthesized from microemulsions of NaBH4 and FeCl3, followed by surface modification in which a thin hydrophobic hexamethyldisilazane layer - used to protect the iron core - replaced the CTAB coating on the particles. Phosphatidylcholine was then assembled on the nanoparticle surface. The resulting nanocomposite particles have a biocompatible surface and show good stability in both air and aqueous solution. Compared to iron oxide nanoparticles, the nanocomposites show much better heating in an alternating magnetic field. They are good candidates for both hyperthermia and magnetic resonance imaging applications. PMID:21833157

  4. Iron Oxide as an MRI Contrast Agent for Cell Tracking

    PubMed Central

    Korchinski, Daniel J.; Taha, May; Yang, Runze; Nathoo, Nabeela; Dunn, Jeff F.

    2015-01-01

    Iron oxide contrast agents have been combined with magnetic resonance imaging for cell tracking. In this review, we discuss coating properties and provide an overview of ex vivo and in vivo labeling of different cell types, including stem cells, red blood cells, and monocytes/macrophages. Furthermore, we provide examples of applications of cell tracking with iron contrast agents in stroke, multiple sclerosis, cancer, arteriovenous malformations, and aortic and cerebral aneurysms. Attempts at quantifying iron oxide concentrations and other vascular properties are examined. We advise on designing studies using iron contrast agents including methods for validation. PMID:26483609

  5. Studies of the kinetics and mechanisms of perfluoroether reactions on iron and oxidized iron surfaces

    NASA Technical Reports Server (NTRS)

    Napier, Mary E.; Stair, Peter C.

    1992-01-01

    Polymeric perfluoroalkylethers are being considered for use as lubricants in high temperature applications, but have been observed to catalytically decompose in the presence of metals. X-ray photoelectron spectroscopy (XPS) and temperature programmed desorption (TPD) were used to explore the decomposition of three model fluorinated ethers on clean polycrystalline iron surfaces and iron surfaces chemically modified with oxygen. Low temperature adsorption of the model fluorinated ethers on the clean, oxygen modified and oxidized iron surfaces was molecular. Thermally activated defluorination of the three model compounds was observed on the clean iron surface at remarkably low temperatures, 155 K and below, with formation of iron fluoride. Preferential C-F bond scission occurred at the terminal fluoromethoxy, CF3O, of perfluoro-1-methoxy-2-ethoxy ethane and perfluoro-1-methoxy-2-ethoxy propane and at CF3/CF2O of perfluoro-1,3-diethoxy propane. The reactivity of the clean iron toward perfluoroalkylether decomposition when compared to other metals is due to the strength of the iron fluoride bond and the strong electron donating ability of the metallic iron. Chemisorption of an oxygen overlayer lowered the reactivity of the iron surface to the adsorption and decomposition of the three model fluorinated ethers by blocking active sites on the metal surface. Incomplete coverage of the iron surface with chemisorbed oxygen results in a reaction which resembles the defluorination reaction observed on the clean iron surface. Perfluoro-1-methoxy-2-ethoxy ethane reacts on the oxidized iron surface at 138 K, through a Lewis acid assisted cleavage of the carbon oxygen bond, with preferential attack at the terminal fluoromethoxy, CF3O. The oxidized iron surface did not passivate, but became more reactive with time. Perfluoro-1-methoxy-2-ethoxy propane and perfluoro-1,3-diethoxy propane desorbed prior to the observation of decomposition on the oxidized iron surface.

  6. Intravenous iron, inflammation, and oxidative stress: is iron a friend or an enemy of uremic patients?

    PubMed

    Garneata, Liliana

    2008-01-01

    Intravenous iron supplementation is a recognized therapy for anemia in chronic hemodialysis patients, especially in those treated with erythropoietin. The vast majority of patients with chronic kidney disease (CKD) seem to be iron-deficient, as evaluated by the usual parameters and by iron staining on bone marrow biopsy, because of multiple forms of interference with all phases of iron metabolism. The need for iron supplementation in CKD patients becomes obvious. Intravenous iron was demonstrated to be superior to oral iron in hemodialysis patients. There is also evidence for the superiority of intravenous iron in peritoneal dialysis and in nondialysis-dependent CKD patients. On the other hand, intravenous iron could promote cytotoxicity and tissue injury, and exacerbate oxidative stress and thus endothelial dysfunction, as well as inflammation and the progression of both CKD and cardiovascular disease. Nevertheless, correction of anemia is effective in reducing oxidative stress and, consequently, cardiovascular risk. The overall risk-benefit ratio favors the use of intravenous iron alone or with an erythropoietic stimulating agent in the management of renal anemia. Clinical judgment is necessary in each individual case to diagnose iron deficiency and effectively use intravenous iron.

  7. Magnetization measurements and XMCD studies on ion irradiated iron oxide and core-shell iron/iron-oxide nanomaterials

    SciTech Connect

    Kaur, Maninder; Qiang, You; Jiang, Weilin; Pearce, Carolyn; McCloy, John S.

    2014-12-02

    Magnetite (Fe3O4) and core-shell iron/iron-oxide (Fe/Fe3O4) nanomaterials prepared by a cluster deposition system were irradiated with 5.5 MeV Si2+ ions and the structures determined by x-ray diffraction as consisting of 100% magnetite and 36/64 wt% Fe/FeO, respectively. However, x-ray magnetic circular dichroism (XMCD) indicates similar surfaces in the two samples, slightly oxidized and so having more Fe3+ than the expected magnetite structure, with XMCD intensity much lower for the irradiated core-shell samples indicating weaker magnetism. X-ray absorption spectroscopy (XAS) data lack the signature for FeO, but the irradiated core-shell system consists of Fe-cores with ~13 nm of separating oxide crystallite, so it is likely that FeO exists deeper than the probe depth of the XAS (~5 nm). Exchange bias (Hex) for both samples becomes increasingly negative as temperature is lowered, but the irradiated Fe3O4 sample shows greater sensitivity of cooling field on Hex. Loop asymmetries and Hex sensitivities of the irradiated Fe3O4 sample are due to interfaces and interactions between grains which were not present in samples before irradiation as well as surface oxidation. Asymmetries in the hysteresis curves of the irradiated core/shell sample are related to the reversal mechanism of the antiferromagnetic FeO and possibly some near surface oxidation.

  8. Application of novel iron core/iron oxide shell nanoparticles to sentinel lymph node identification

    NASA Astrophysics Data System (ADS)

    Cousins, Aidan; Howard, Douglas; Henning, Anna M.; Nelson, Melanie R. M.; Tilley, Richard D.; Thierry, Benjamin

    2015-12-01

    Current `gold standard' staging of breast cancer and melanoma relies on accurate in vivo identification of the sentinel lymph node. By replacing conventional tracers (dyes and radiocolloids) with magnetic nanoparticles and using a handheld magnetometer probe for in vivo identification, it is believed the accuracy of sentinel node identification in nonsuperficial cancers can be improved due to increased spatial resolution of magnetometer probes and additional anatomical information afforded by MRI road-mapping. By using novel iron core/iron oxide shell nanoparticles, the sensitivity of sentinel node mapping via MRI can be increased due to an increased magnetic saturation compared to traditional iron oxide nanoparticles. A series of in vitro magnetic phantoms (iron core vs. iron oxide nanoparticles) were prepared to simulate magnetic particle accumulation in the sentinel lymph node. A novel handheld magnetometer probe was used to measure the relative signals of each phantom, and determine if clinical application of iron core particles can improve in vivo detection of the sentinel node compared to traditional iron oxide nanoparticles. The findings indicate that novel iron core nanoparticles above a certain size possess high magnetic saturation, but can also be produced with low coercivity and high susceptibility. While some modification to the design of handheld magnetometer probes may be required for particles with large coercivity, use of iron core particles could improve MRI and magnetometer probe detection sensitivity by up to 330 %.

  9. Magnetic Properties of Core/Shell Structured Iron/Iron-oxide Nanoparticles Dispersed in Polymer Matrix

    NASA Astrophysics Data System (ADS)

    Nemati Porshokouh, Zohreh; Khurshid, Hafsa; Phan, Manh-Huong; Srikanth, Hariharan

    2014-03-01

    Iron-based nanoparticles (NPs) show interesting magnetic properties for a wide range of applications; however rapid oxidation of iron limits its practical use. Protecting iron with a thin layer of iron-oxide is a possible way to prevent oxidation, forming core/shell (CS) iron/iron-oxide. Due to the different diffusivity rates of the two materials, a gap appears between the core and shell after a period of time (Kirkendall effect), degrading the magnetic properties of the sample. We minimize the Kirkendall effect while retaining good magnetic properties of ~12.5 nm CS iron/iron-oxide NPs by dispersing them into a polymer matrix. Magnetic measurements reveal that after a period of 3 months the blocking temperature (TB) of as-made CS NPs decreases from 107 K to 90 K. The change in TB marks the formation of a gap between the core and shell, which is also evident from HRTEM studies. By contrast, NPs dispersed in RP show no change in TB over the same time period. We repeated experiments with ~10.5 nm CS NPs and the results are consistent. Our study shows the importance of dispersing CS NPs in polymers to preserve desirable magnetic properties for practical applications, ranging from RF sensors and microwave devices to bioengineering.

  10. Oxidative Stress and the Homeodynamics of Iron Metabolism

    PubMed Central

    Bresgen, Nikolaus; Eckl, Peter M.

    2015-01-01

    Iron and oxygen share a delicate partnership since both are indispensable for survival, but if the partnership becomes inadequate, this may rapidly terminate life. Virtually all cell components are directly or indirectly affected by cellular iron metabolism, which represents a complex, redox-based machinery that is controlled by, and essential to, metabolic requirements. Under conditions of increased oxidative stress—i.e., enhanced formation of reactive oxygen species (ROS)—however, this machinery may turn into a potential threat, the continued requirement for iron promoting adverse reactions such as the iron/H2O2-based formation of hydroxyl radicals, which exacerbate the initial pro-oxidant condition. This review will discuss the multifaceted homeodynamics of cellular iron management under normal conditions as well as in the context of oxidative stress. PMID:25970586

  11. Immobilisation of arsenic by iron(II)-oxidizing bacteria

    NASA Astrophysics Data System (ADS)

    Kappler, A.; Hohmann, C.; Winkler, E.; Muehe, M.; Morin, G.

    2008-12-01

    Arsenic-contaminated groundwater is an environmental problem that affects about 1-2% of the world's population. As arsenic-contaminated water is also used for irrigating rice fields, the uptake of arsenic via rice is in some cases even higher than via drinking water. Arsenic is often of geogenic origin and in many cases bound to iron(III) minerals. Microbial iron(III) reduction leads to dissolution of Fe(III) minerals and thus the arsenic bound to these minerals is released to the environment. In turn, iron(II)-oxidizing bacteria have the potential to co-precipitate or sorb arsenic during iron(II) oxidation followed by iron(III) mineral formation. Here, we present work on arsenic co-precipitation and immobilization by anaerobic and aerobic iron(II)-oxidizing bacteria. Co-precipitation batch experiments with pure cultures of nitrate-dependent, phototrophic, and microaerophilic Fe(II)-oxidizing bacteria are used to quantify the amount of arsenic that can be immobilized during microbial iron mineral precipitation. Iron and arsenic speciation and redox state are determined by X- ray diffraction and synchrotron-based X-ray absorption methods (EXAFS, XANES). Microcosm experiments are set-up either with liquid media or with rice paddy soil amended with arsenic. Rice paddy soil from arsenic contaminated rice fields in China that include a natural population of Fe(II)-oxidizing microorganisms is used as inoculum. Dissolved and solid-phase arsenic and iron are quantified, Arsenic speciation is determined and the iron minerals are identified. Additionally, Arsenic uptake into the rice plant is quantified and a gene expression pattern in rice (Oryza sativa cv Gladia) is determined by microarrays as a response to the presence of Fe(II)-oxidizing bacteria.

  12. Manganese and iron oxidation by fungi isolated from building stone.

    PubMed

    de la Torre, M A; Gomez-Alarcon, G

    1994-01-01

    Acid and nonacid generating fungal strains isolated from weathered sandstone, limestone, and granite of Spanish cathedrals were assayed for their ability to oxidize iron and manganese. In general, the concentration of the different cations present in the mineral salt media directly affected Mn(IV) oxide formation, although in some cases, the addition of glucose and nitrate to the culture media was necessary. Mn(II) oxidation in acidogenic strains was greater in a medium containing the highest concentrations of glucose, nitrate, and manganese. High concentrations of Fe(II), glucose, and mineral salts were optimal for iron oxidation. Mn(IV) precipitated as oxides or hydroxides adhered to the mycelium. Most of the Fe(III) remained in solution by chelation with organic acids excreted by acidogenic strains. Other metabolites acted as Fe(III) chelators in nonacidogenic strains, although Fe(III) deposits around the mycelium were also detected. Both iron and manganese oxidation were shown to involve extracellular, hydrosoluble enzymes, with maximum specific activities during exponential growth. Strains able to oxidize manganese were also able to oxidize iron. It is concluded that iron and manganese oxidation reported in this work were biologically induced by filamentous fungi mainly by direct (enzymatic) mechanisms.

  13. Sorption of strontium onto bacteriogenic iron oxides.

    PubMed

    Langley, Sean; Gault, Andrew G; Ibrahim, Alexandre; Takahashi, Yoshio; Renaud, Rob; Fortin, Danielle; Clark, Ian D; Ferris, F Grant

    2009-02-15

    Bacteriogenic iron oxides (BIOS) were obtained from a dilute, circumneutral groundwater seep, characterized with respect to mineralogy, and examined for their ability to sorb aqueous Sr2+. BIOS were composed of microbial sheaths encrusted in 2-line ferrihydrite. Sorption experiments indicated that Sr remained completely unbound at pH < 4.5, but sorption increased with increasing pH (maximum of 95% at pH > 7.6). EXAFS analysis of Sr-loaded BIOS failed to elucidate whether Sr sorption occurred on sites specific to the mineral or microbial fraction, but indicated that sorption likely occurred by outer-sphere complexation between BIOS and hydrated Sr2+. Sorption experiments showed that at low ionic strength (I = 0.001 M), sorption followed a Langmuir isotherm (S(max) = 3.41 mol Sr (g of Fe)(1-), K(ads) = 1.26). At higher ionic strength (I = 0.1 M), there was significant inhibition of Sr sorption (S(max) = 1.06 mol Sr (g of Fe)(1-), K(ads) = 1.23), suggesting that sorption to BIOS occurs by outer-sphere complexation. The results suggest that, under dilute circumneutral conditions, BIOS deposits should efficiently sorb dissolved Sr from groundwater flow systems where such deposits exist. This finding has particular relevance to sites impacted by radioactive 90Sr groundwater contamination. PMID:19320150

  14. Sorption of strontium onto bacteriogenic iron oxides.

    PubMed

    Langley, Sean; Gault, Andrew G; Ibrahim, Alexandre; Takahashi, Yoshio; Renaud, Rob; Fortin, Danielle; Clark, Ian D; Ferris, F Grant

    2009-02-15

    Bacteriogenic iron oxides (BIOS) were obtained from a dilute, circumneutral groundwater seep, characterized with respect to mineralogy, and examined for their ability to sorb aqueous Sr2+. BIOS were composed of microbial sheaths encrusted in 2-line ferrihydrite. Sorption experiments indicated that Sr remained completely unbound at pH < 4.5, but sorption increased with increasing pH (maximum of 95% at pH > 7.6). EXAFS analysis of Sr-loaded BIOS failed to elucidate whether Sr sorption occurred on sites specific to the mineral or microbial fraction, but indicated that sorption likely occurred by outer-sphere complexation between BIOS and hydrated Sr2+. Sorption experiments showed that at low ionic strength (I = 0.001 M), sorption followed a Langmuir isotherm (S(max) = 3.41 mol Sr (g of Fe)(1-), K(ads) = 1.26). At higher ionic strength (I = 0.1 M), there was significant inhibition of Sr sorption (S(max) = 1.06 mol Sr (g of Fe)(1-), K(ads) = 1.23), suggesting that sorption to BIOS occurs by outer-sphere complexation. The results suggest that, under dilute circumneutral conditions, BIOS deposits should efficiently sorb dissolved Sr from groundwater flow systems where such deposits exist. This finding has particular relevance to sites impacted by radioactive 90Sr groundwater contamination.

  15. Stem cell tracking using iron oxide nanoparticles.

    PubMed

    Bull, Elizabeth; Madani, Seyed Yazdan; Sheth, Roosey; Seifalian, Amelia; Green, Mark; Seifalian, Alexander M

    2014-01-01

    Superparamagnetic iron oxide nanoparticles (SPIONs) are an exciting advancement in the field of nanotechnology. They expand the possibilities of noninvasive analysis and have many useful properties, making them potential candidates for numerous novel applications. Notably, they have been shown that they can be tracked by magnetic resonance imaging (MRI) and are capable of conjugation with various cell types, including stem cells. In-depth research has been undertaken to establish these benefits, so that a deeper level of understanding of stem cell migratory pathways and differentiation, tumor migration, and improved drug delivery can be achieved. Stem cells have the ability to treat and cure many debilitating diseases with limited side effects, but a main problem that arises is in the noninvasive tracking and analysis of these stem cells. Recently, researchers have acknowledged the use of SPIONs for this purpose and have set out to establish suitable protocols for coating and attachment, so as to bring MRI tracking of SPION-labeled stem cells into common practice. This review paper explains the manner in which SPIONs are produced, conjugated, and tracked using MRI, as well as a discussion on their limitations. A concise summary of recently researched magnetic particle coatings is provided, and the effects of SPIONs on stem cells are evaluated, while animal and human studies investigating the role of SPIONs in stem cell tracking will be explored.

  16. Magnetic Iron Oxide Nanoparticles: Synthesis and Surface Functionalization Strategies

    NASA Astrophysics Data System (ADS)

    Wu, Wei; He, Quanguo; Jiang, Changzhong

    2008-10-01

    Surface functionalized magnetic iron oxide nanoparticles (NPs) are a kind of novel functional materials, which have been widely used in the biotechnology and catalysis. This review focuses on the recent development and various strategies in preparation, structure, and magnetic properties of naked and surface functionalized iron oxide NPs and their corresponding application briefly. In order to implement the practical application, the particles must have combined properties of high magnetic saturation, stability, biocompatibility, and interactive functions at the surface. Moreover, the surface of iron oxide NPs could be modified by organic materials or inorganic materials, such as polymers, biomolecules, silica, metals, etc. The problems and major challenges, along with the directions for the synthesis and surface functionalization of iron oxide NPs, are considered. Finally, some future trends and prospective in these research areas are also discussed.

  17. Magnetic Iron Oxide Nanoparticles: Synthesis and Surface Functionalization Strategies

    PubMed Central

    2008-01-01

    Surface functionalized magnetic iron oxide nanoparticles (NPs) are a kind of novel functional materials, which have been widely used in the biotechnology and catalysis. This review focuses on the recent development and various strategies in preparation, structure, and magnetic properties of naked and surface functionalized iron oxide NPs and their corresponding application briefly. In order to implement the practical application, the particles must have combined properties of high magnetic saturation, stability, biocompatibility, and interactive functions at the surface. Moreover, the surface of iron oxide NPs could be modified by organic materials or inorganic materials, such as polymers, biomolecules, silica, metals, etc. The problems and major challenges, along with the directions for the synthesis and surface functionalization of iron oxide NPs, are considered. Finally, some future trends and prospective in these research areas are also discussed. PMID:21749733

  18. Synthesis and heating effect of iron/iron oxide composite and iron oxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Zeng, Q.; Baker, I.; Loudis, J. A.; Liao, Y. F.; Hoopes, P. J.

    2007-02-01

    Fe/Fe oxide nanoparticles, in which the core consists of metallic Fe and the shell is composed of Fe oxides, were obtained by reduction of an aqueous solution of FeCl 3 within a NaBH 4 solution, or, using a water-in-oil micro-emulsion with CTAB as the surfactant. The reduction was performed either in an inert atmosphere or in air, and passivation with air was performed to produce the Fe/Fe 3O 4 core/shell composite. Phase identification and particle size were determined by X-ray diffraction and TEM. Thermal analysis was performed using a differential scanning calorimeter. The quasistatic magnetic properties were measured using a VSM, and the specific absorption rates (SARs) of both Fe oxide and Fe/Fe 3O 4 composite nanoparticles either dispersed in methanol or in an epoxy resin were measured by Luxtron fiber temperature sensors in an alternating magnetic field of 150 Oe at 250 kHz. It was found that the preparation conditions, including the concentrations of solutions, the mixing procedure and the heat treatment, influence the particle size, the crystal structure and consequently the magnetic properties of the particles. Compared with Fe oxides, the saturation magnetization (MS) of Fe/Fe 3O 4 particles (100-190 emu/g) can be twice as high, and the coercivity (H C) can be tunable from several Oe to several hundred Oe. Hence, the SAR of Fe/Fe 3O 4 composite nanoparticles can be much higher than that of Fe oxides, with a maximum SAR of 345 W/g. The heating behavior is related to the magnetic behavior of the nanoparticles.

  19. 46 CFR 148.275 - Iron oxide, spent; iron sponge, spent.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Iron oxide, spent; iron sponge, spent. 148.275 Section 148.275 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) DANGEROUS CARGOES CARRIAGE... be transported on open hold all-steel barges after exposure to air for a period of at least ten days....

  20. 46 CFR 148.275 - Iron oxide, spent; iron sponge, spent.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Iron oxide, spent; iron sponge, spent. 148.275 Section 148.275 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) DANGEROUS CARGOES CARRIAGE... be transported on open hold all-steel barges after exposure to air for a period of at least ten days....

  1. 46 CFR 148.275 - Iron oxide, spent; iron sponge, spent.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Iron oxide, spent; iron sponge, spent. 148.275 Section 148.275 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) DANGEROUS CARGOES CARRIAGE... be transported on open hold all-steel barges after exposure to air for a period of at least ten days....

  2. Iron oxide-based nanomagnets in nanomedicine: fabrication and applications

    PubMed Central

    Meng Lin, Meng; Kim, Hyung-Hwan; Kim, Hyuck; Muhammed, Mamoun; Kyung Kim, Do

    2010-01-01

    Iron oxide-based nanomagnets have attracted a great deal of attention in nanomedicine over the past decade. Down to the nanoscale, superparamagnetic iron oxide nanoparticles can only be magnetized in the presence of an external magnetic field, which makes them capable of forming stable colloids in a physio-biological medium. Their superparamagnetic property, together with other intrinsic properties, such as low cytotoxicity, colloidal stability, and bioactive molecule conjugation capability, makes such nanomagnets ideal in both in-vitro and in-vivo biomedical applications. In this review, a chemical, physical, and biological synthetic approach to prepare iron oxide-based nanomagnets with different physicochemical properties was illustrated and compared. The growing interest in iron oxide-based nanomagnets with multifunctionalities was explored in cancer diagnostics and treatment, focusing on their combined roles in a magnetic resonance contrast agent, hyperthermia, and magnetic force assisted drug delivery. Iron oxides as magnetic carriers in gene therapy were reviewed with a focus on the sophisticated design and construction of magnetic vectors. Finally, the iron oxide-based nanomagnet also represents a very promising tool in particle/cell interfacing in controlling cellular functionalities, such as adhesion, proliferation, differentiation, and cell patterning, in stem cell therapy and tissue engineering applications. PMID:22110854

  3. Iron oxide nanoparticles in geomicrobiology: from biogeochemistry to bioremediation.

    PubMed

    Braunschweig, Juliane; Bosch, Julian; Meckenstock, Rainer U

    2013-09-25

    Iron oxides are important constituents of soils and sediments and microbial iron reduction is considered to be a significant anaerobic respiration process in the subsurface, however low microbial reduction rates of macroparticulate Fe oxides in laboratory studies led to an underestimation of the role of Fe oxides in the global Fe redox cycle. Recent studies show the high potential of nano-sized Fe oxides in the environment as, for example, electron acceptor for microbial respiration, electron shuttle between different microorganisms, and scavenger for heavy metals. Biotic and abiotic reactivity of iron macroparticles differ significantly from nano-sized Fe oxides, which are usually much more reactive. Factors such as particle size, solubility, ferrous iron, crystal structure, and organic molecules were identified to influence the reactivity. This review discusses factors influencing the microbial reactivity of Fe oxides. It highlights the differences between natural and synthetic Fe oxides especially regarding the presence of organic molecules such as humic acids and natural organic matter. Attention is given to the transport behavior of Fe oxides in laboratory systems and in the environment, because of the high affinity of different contaminants to Fe oxide surfaces and associated co-transport of pollutants. The high reactivity of Fe oxides and their potential as adsorbents for different pollutants are discussed with respect to application and development of remediation technologies.

  4. Iron, oxidative stress, and redox signaling in the cardiovascular system.

    PubMed

    Gudjoncik, Aurélie; Guenancia, Charles; Zeller, Marianne; Cottin, Yves; Vergely, Catherine; Rochette, Luc

    2014-08-01

    The redox state of the cell is predominantly dependent on an iron redox couple and is maintained within strict physiological limits. Iron is an essential metal for hemoglobin synthesis in erythrocytes, for oxidation-reduction reactions, and for cellular proliferation. The maintenance of stable iron concentrations requires the coordinated regulation of iron transport into plasma from dietary sources in the duodenum, from recycled senescent red cells in macrophages, and from storage in hepatocytes. The absorption of dietary iron, which is present in heme or nonheme form, is carried out by mature villus enterocytes of the duodenum and proximal jejunum. Multiple physiological processes are involved in maintaining iron homeostasis. These include its storage at the intracellular and extracellular level. Control of iron balance in the whole organism requires communication between sites of uptake, utilization, and storage. Key protein transporters and the molecules that regulate their activities have been identified. In this field, ferritins and hepcidin are the major regulator proteins. A variety of transcription factors may be activated depending on the level of oxidative stress, leading to the expression of different genes. Major preclinical and clinical trials have shown advances in iron-chelation therapy for the treatment of iron-overload disease as well as cardiovascular and chronic inflammatory diseases.

  5. Iron, oxidative stress, and redox signaling in the cardiovascular system.

    PubMed

    Gudjoncik, Aurélie; Guenancia, Charles; Zeller, Marianne; Cottin, Yves; Vergely, Catherine; Rochette, Luc

    2014-08-01

    The redox state of the cell is predominantly dependent on an iron redox couple and is maintained within strict physiological limits. Iron is an essential metal for hemoglobin synthesis in erythrocytes, for oxidation-reduction reactions, and for cellular proliferation. The maintenance of stable iron concentrations requires the coordinated regulation of iron transport into plasma from dietary sources in the duodenum, from recycled senescent red cells in macrophages, and from storage in hepatocytes. The absorption of dietary iron, which is present in heme or nonheme form, is carried out by mature villus enterocytes of the duodenum and proximal jejunum. Multiple physiological processes are involved in maintaining iron homeostasis. These include its storage at the intracellular and extracellular level. Control of iron balance in the whole organism requires communication between sites of uptake, utilization, and storage. Key protein transporters and the molecules that regulate their activities have been identified. In this field, ferritins and hepcidin are the major regulator proteins. A variety of transcription factors may be activated depending on the level of oxidative stress, leading to the expression of different genes. Major preclinical and clinical trials have shown advances in iron-chelation therapy for the treatment of iron-overload disease as well as cardiovascular and chronic inflammatory diseases. PMID:24888568

  6. Inflammatory imaging with ultrasmall superparamagnetic iron oxide.

    PubMed

    Matsushita, Taro; Kusakabe, Yoshinori; Fujii, Hitomi; Murase, Katsutoshi; Yamazaki, Youichi; Murase, Kenya

    2011-02-01

    The purpose of this study was to investigate the usefulness and feasibility of magnetic resonance imaging (MRI) with ultrasmall superparamagnetic iron oxide (USPIO) (USPIO-enhanced MRI) for imaging inflammatory tissues. First, we investigated the relationship between the apparent transverse relaxation rate (R2*) and the concentration of USPIO by phantom studies and measured the apparent transverse relaxivity (r2*) of USPIO. Second, we performed animal experiments using a total of 30 mice. The mice were divided into five groups [A (n=6), B (n=6), C (n=6), sham control (n=6), and control (n=6)]. The mice in Groups A, B, C and control were subcutaneously injected with 0.1 ml of turpentine oil on Day 0, while those in the sham control group were subcutaneously injected with 0.1 ml of saline. The mice in Groups A, B, C and sham control were intraperitoneally injected with 200 μmol Fe per kilogram body weight of USPIO (28 nm in diameter) immediately after the first MRI study on Days 3, 5, 7 and 7, respectively, and those in the control group were not injected with USPIO. The second and third MRI studies were performed at 24 and 48 h after USPIO administration, respectively. The maps of R2* were generated from the apparent transverse relaxation time (T2*)-weighted images with six different echo times. The phantom studies showed that there was a linear relationship between R2* and the concentration of USPIO (r=0.99) and the r2* value of USPIO was 105.7 mM(-1) s(-1). There was a significant increase of R2* in inflammatory tissues in Group C at 24 h after USPIO administration compared with the precontrast R2* value. Our results suggest that USPIO-enhanced MRI combined with R2* measurement is useful for detecting inflammatory tissues. PMID:20850245

  7. Iron release and oxidant damage in human myoblasts by divicine.

    PubMed

    Ninfali, P; Perini, M P; Bresolin, N; Aluigi, G; Cambiaggi, C; Ferrali, M; Pompella, A

    2000-01-01

    Divicine is an aglycone derived from vicine, a glucosidic compound contained in fava beans (Vicia faba major or broad beans). In this study, we investigated the effect of divicine on cultured human myoblasts from normal subjects, in order to see if the drug may induce signs of oxidant stress in these cells. Myoblasts incubated 24 hours in the presence of 1 mM divicine, showed an increase of carbonyl groups and 4-hydroxynonenal (4-HNE) bound to cell proteins, as well as a significant release of iron and lactate dehydrogenase in the culture medium. Desferrioxamine (DFO), an iron chelator, significantly prevented protein oxidation and formation 4-HNE adducts. Our results can be interpreted as indicating that divicine autooxidizes both at extracellular level and into myoblasts thus inducing the release of free iron, which initiates oxidation of cellular proteins and lipids. DFO protects the cells by subtracting the free iron both at intracellular and extracellular level. PMID:10794072

  8. Analysis of iron oxide precipitates in constructed mine wastewater treatments

    SciTech Connect

    Partezana, J.M.

    1996-10-01

    The purpose or this research project is to characterize iron oxide precipitates collected from abandoned mine drainage (AMD) treatment facilities in order to determine whether these precipitates have possible commercial value. The treatment facilities use constructed wetlands to raise pH levels to near neutral levels and to remove iron and other heavy metals from AMD polluted water. The main commercial value of interest is in the use of pigments in products such as paints, clay and brick. The precipitates arc characterized for composition and quality against natural and synthetic commercial pigment products. Various processing techniques were developed for sample preparation. Analysis tests include: general pigment tests, heavy metals, anions, particle size, and particle composition. Results show that the iron oxide precipitates are chemically similar to the commercial iron oxide but will require additional processing to meet pigment qualifications.

  9. Iron accumulation with age, oxidative stress and functional decline.

    PubMed

    Xu, Jinze; Knutson, Mitchell D; Carter, Christy S; Leeuwenburgh, Christiaan

    2008-01-01

    Identification of biological mediators in sarcopenia is pertinent to the development of targeted interventions to alleviate this condition. Iron is recognized as a potent pro-oxidant and a catalyst for the formation of reactive oxygen species in biological systems. It is well accepted that iron accumulates with senescence in several organs, but little is known about iron accumulation in muscle and how it may affect muscle function. In addition, it is unclear if interventions which reduced age-related loss of muscle quality, such as calorie restriction, impact iron accumulation. We investigated non-heme iron concentration, oxidative stress to nucleic acids in gastrocnemius muscle and key indices of sarcopenia (muscle mass and grip strength) in male Fischer 344 X Brown Norway rats fed ad libitum (AL) or a calorie restricted diet (60% of ad libitum food intake starting at 4 months of age) at 8, 18, 29 and 37 months of age. Total non-heme iron levels in the gastrocnemius muscle of AL rats increased progressively with age. Between 29 and 37 months of age, the non-heme iron concentration increased by approximately 200% in AL-fed rats. Most importantly, the levels of oxidized RNA in gastrocnemius muscle of AL rats were significantly increased as well. The striking age-associated increase in non-heme iron and oxidized RNA levels and decrease in sarcopenia indices were all attenuated in the calorie restriction (CR) rats. These findings strongly suggest that the age-related iron accumulation in muscle contributes to increased oxidative damage and sarcopenia, and that CR effectively attenuates these negative effects.

  10. Iron Accumulation with Age, Oxidative Stress and Functional Decline

    PubMed Central

    Xu, Jinze; Knutson, Mitchell D.; Carter, Christy S.; Leeuwenburgh, Christiaan

    2008-01-01

    Identification of biological mediators in sarcopenia is pertinent to the development of targeted interventions to alleviate this condition. Iron is recognized as a potent pro-oxidant and a catalyst for the formation of reactive oxygen species in biological systems. It is well accepted that iron accumulates with senescence in several organs, but little is known about iron accumulation in muscle and how it may affect muscle function. In addition, it is unclear if interventions which reduced age-related loss of muscle quality, such as calorie restriction, impact iron accumulation. We investigated non-heme iron concentration, oxidative stress to nucleic acids in gastrocnemius muscle and key indices of sarcopenia (muscle mass and grip strength) in male Fischer 344 X Brown Norway rats fed ad libitum (AL) or a calorie restricted diet (60% of ad libitum food intake starting at 4 months of age) at 8, 18, 29 and 37 months of age. Total non-heme iron levels in the gastrocnemius muscle of AL rats increased progressively with age. Between 29 and 37 months of age, the non-heme iron concentration increased by approximately 200% in AL-fed rats. Most importantly, the levels of oxidized RNA in gastrocnemius muscle of AL rats were significantly increased as well. The striking age-associated increase in non-heme iron and oxidized RNA levels and decrease in sarcopenia indices were all attenuated in the calorie restriction (CR) rats. These findings strongly suggest that the age-related iron accumulation in muscle contributes to increased oxidative damage and sarcopenia, and that CR effectively attenuates these negative effects. PMID:18682742

  11. Oxidation-Induced Degradable Nanogels for Iron Chelation

    PubMed Central

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

    2016-01-01

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

  12. Synthesis of carbon-encapsulated iron nanoparticles via solid state reduction of iron oxide nanoparticles

    SciTech Connect

    Bystrzejewski, M.

    2011-06-15

    The encapsulation of iron nanoparticles in protective carbon cages leads to unique hybrid core-shell nanomaterials. Recent literature reports suggest that such nanocomposites can be obtained in a relatively simple process involving the solid state carbothermal reduction of iron oxide nanoparticles. This approach is very attractive because it does not require advanced equipment and consumes less energy in comparison to widely used plasma methods. The presented more-in-depth study shows that the carbothermal approach is sensitive to temperature and the process yield strongly depends on the morphology and crystallinity of the carbon material used as a reductant. - Graphical abstract: Reduction of iron oxide nanoparticles by carbon black at 1200 deg. C yields well crystallized carbon-encapsulated iron nanoparticles. Highlights: > Carbon-encapsulated iron nanoparticles were synthesized by carbothermal reduction of iron oxide nanoparticles. > The process has the highest selectivity at 1200 C. > Lower temperatures result in iron oxide nanoparticles wrapped in carbon matrix. > The encapsulation rate of Fe at 1200 deg. C was found to be 15%.

  13. The Oxidation Of Iron In A Gel Using Consumer Chemicals

    ERIC Educational Resources Information Center

    Wright, Stephen W.; Folger, Marsha R.; Quinn, Ryan P.; Sauls, Frederick C.; Krone, Diane

    2005-01-01

    An experiment is conducted for the oxidation of iron in a gel using consumer chemicals, which is pertinent to the students' understanding of redox chemistry and of the relative oxidation potentials of various metals. The experiment can be carried out with consumer chemicals that might be purchased at a supermarket and commonly found in the home.

  14. Synthesis of phase pure praseodymium barium copper iron oxide.

    PubMed

    Konne, Joshua L; Davis, Sean A; Glatzel, Stefan; Hall, Simon R

    2013-06-18

    The control of crystallization of praseodymium barium copper iron oxide, an intermediate temperature solid oxide fuel cell cathode material, has been demonstrated for the first time using a biotemplated sol-gel synthesis technique. The results obtained showed significant improvement in purity, synthesis time, surface area and simplicity over that previously reported.

  15. Photochemical Activation of Chlorine by Iron and Iron Oxide Aerosol

    NASA Astrophysics Data System (ADS)

    Wittmer, J.; Zetzsch, C.

    2015-12-01

    The photochemical activation of chlorine by dissolved iron in sea-salt aerosol droplets and by highly dispersed Fe2O3 aerosol particles (mainly hematite, specific surface > 100 m2/g), exposed to gaseous HCl, was investigated in humidified air in a Teflon simulation chamber. Employing the radical-clock technique, we quantified the production of gaseous atomic Cl. When the artificial sea salt aerosols contained suspended Fe2O3 alone at pH 6, no significant Cl production could be observed, even if the dissolution of iron was forced by "weathering" (repeatedly freezing and thawing for five times). Adjusting the pH in the stock suspension to 2.6, 2.2, and 1.9 and equilibrating for one week resulted in a quantifiable amount of dissolved iron (0.03, 0.2, and 0.6 mmol/L, respectively) and in gaseous Cl production rates of ~1.6, 6, and 8 × 1021 atoms cm-2 h-1, respectively. Exposing the pure Fe2O3 aerosol in the absence of salt to various gaseous HCl concentrations resulted in rates ranging from 8 × 1020 Cl atoms cm-2 h-1 (at ~4 ppb HCl) to 5 × 1022 Cl atoms cm-2 h-1 (at ~350 ppb HCl) and confirmed the uptake and conversion of HCl to atomic Cl (at HCl to Cl conversion yields of 2-5 % mol/mol, depending on the relative humidity). The relevance for environmental processes in the atmosphere will be discussed.

  16. Potassium promotion of iron oxide dehydrogenation catalysts supported on magnesium oxide: 1. Preparation and characterization

    SciTech Connect

    Stobbe, D.E.; Buren, F.R. van ); Dillen, A.J. van; Geus, J.W. )

    1992-06-01

    Catalysts of iron oxide supported on magnesium oxide and promoted with potassium were prepared by incipient wetness impregnation of preshaped magnesium oxide support pellets with a solution of an iron complex, either ammonium iron (III) citrate or ammonium iron (III) EDTA and potassium carbonate. Iron and potassium were applied wither simultaneously or consecutively. As determined using X-ray diffraction, thermogravimetric analysis, and magnetic measurements, calcination above 923 K results in the formation of a mixed oxide of iron and potassium, viz., KFeO[sub 2]. After calcination at 973 K the average crystallite size of the KFeO[sub 2] phase is about 300 [angstrom]. The formation of KFeO[sub 2] appeared to have a strong retarding effect on the reduction of the iron oxide phase to metallic iron. It was found that the KFeO[sub 2] phase is unstable in atomspheric air due to reaction with carbon dioxide and moisture to form potassium (hydrogen) carbonate and (hydrated) iron oxide.

  17. Biogeochemistry of Iron Oxidation in a Circumneutral Freshwater Habitat

    NASA Astrophysics Data System (ADS)

    Duckworth, O.; Homstrom, S.; Pena, J.; Zacharias, E.; Sposito, G.

    2007-12-01

    Iron(II) oxidation in natural waters at circumneutral pH, often regarded as an abiotic process, may be biologically- mediated when it occurs in iron-rich redox gradients. West Berry Creek, a small circumneutral tributary flowing through a mixed coniferous forest in Big Basin State Park, California, contains localized iron (hydr)oxide precipitates at points along its course where anoxic groundwater meets oxygenated creek water. These mixing zones establish redox gradients and iron-rich microbial mats that may create microenvironments that promote active biogeochemical cycling of Fe. Water sampling revealed strong correlations between the concentrations of aqueous inorganic species, suggesting a rock-weathering source for most of these solutes. Liquid chromatography-mass spectrometry detected significant concentrations of organic exudates, including low molecular mass organic acids and siderophores, indicating active biogeochemical cycling of iron is occurring in the creek. X-ray diffraction and elemental analysis showed the iron precipitates to be amorphous minerals, such as ferrihydrite. Microbial biofilm communities are associated with the iron (hydr)oxide deposits. Clone libraries developed from 16s rDNA sequences revealed the presence of microorganisms related to the neutrophilic iron- oxidizing bacteria Gallionella and Siderooxidans; in addition, micrographs suggest the widespread presence of sheath-forming bacteria (e.g., Leptothrix). Sequences from these libraries also indicated the presence of significant populations of organisms related to bacteria in the genera Pseudomonas, Sphingomonas, and Nitrospira. These geosymbiotic systems appear to be significant not only for the biogeochemical cycling of iron in the creek, but also for the cycling of organic species, inorganic nutrients, and trace metals.

  18. Polymer assisted preparation and characterization of ZnO and Sn doped ZnO nanostructures

    NASA Astrophysics Data System (ADS)

    Santhosh Kumar, A.; Nagaraja, K. K.; Nagaraja, H. S.

    2015-02-01

    Zinc oxide (ZnO) and tin doped ZnO are wide band gap semiconducting materials with excellent optoelectronic properties. In the present study ZnO and Sn: ZnO films are prepared using polymer assisted sol gel process. The thermal behaviour of the dried gel sample studied using DTA and TG analysis. TG-DTA result shown that most of the organic of PVA and CH3COO group of zinc acetate and other volatiles are removed below 500°C. The effect of Sn on the crystallinity, microstructral properties of the deposited films was investigated. XRD patterns of undoped and Sn doped ZnO films indicate enhanced intensities for the peak corresponding to (002) plane, resulting preferential orientation along the c-axis. The SEM images confirm that the grown films are composed of nanorods.

  19. Iron and oxidative stress in cardiomyopathy in thalassemia.

    PubMed

    Berdoukas, Vasilios; Coates, Thomas D; Cabantchik, Zvi Ioav

    2015-11-01

    With repeated blood transfusions, patients with thalassemia major rapidly become loaded with iron, often surpassing hepatic metal accumulation capacity within ferritin shells and infiltrating heart and endocrine organs. That pathological scenario contrasts with the physiological one, which is characterized by an efficient maintenance of all plasma iron bound to circulating transferrin, due to a tight control of iron ingress into plasma by the hormone hepcidin. Within cells, most of the acquired iron becomes protein-associated, as once released from endocytosed transferrin, it is used within mitochondria for the synthesis of protein prosthetic groups or it is incorporated into enzyme active centers or alternatively sequestered within ferritin shells. A few cell types also express the iron extrusion transporter ferroportin, which is under the negative control of circulating hepcidin. However, that system only backs up the major cell regulated iron uptake/storage machinery that is poised to maintain a basal level of labile cellular iron for metabolic purposes without incurring potentially toxic scenarios. In thalassemia and other transfusion iron-loading conditions, once transferrin saturation exceeds about 70%, labile forms of iron enter the circulation and can gain access to various types of cells via resident transporters or channels. Within cells, they can attain levels that exceed their ability to chemically cope with labile iron, which has a propensity for generating reactive oxygen species (ROS), thereby inducing oxidative damage. This scenario occurs in the heart of hypertransfused thalassemia major patients who do not receive adequate iron-chelation therapy. Iron that accumulates in cardiomyocytes forms agglomerates that are detected by T2* MRI. The labile forms of iron infiltrate the mitochondria and damage cells by inducing noxious ROS formation, resulting in heart failure. The very rapid relief of cardiac dysfunction seen after intensive iron

  20. Quantification of Iron Oxides and Hydroxides in Desert Aeolian Particles

    NASA Astrophysics Data System (ADS)

    Lafon, S.; Rajot, J.; Alfaro, S.; Gaudichet, A.

    2002-12-01

    Long range transport of desert dust over oceans constitute a source of iron for the surface water. Assessing the iron cycle and its biogeochemical implications in oceanic areas requires determination and quantification of the iron status in aeolian particles. Indeed, in such aerosols, the iron is either trapped in the silicate structure or present under the form of oxides and hydroxides (free iron). We propose a method to apportion iron between free and entrapped forms in mineral aerosols. It consists in the adaptation of a well known method used for soil characterization to the treatment of aerosol samples, which represent less than 1 mg of material collected by air filtration on polycarbonate filters. The iron oxides and hydroxides are extracted selectively using the combined action of reductive and complexant agents in a buffered solution. The iron content is measured before and after this chemical extraction using X ray fluorescence spectrometry. We attempt to give some values for three main desert source areas using aerosol samples collected near Niamey (Niger) either during Harmattan events or during local erosion events, and samples collected downwind of the Gobi desert in China. Results emphasize firstly that iron trapped in the structure of silicate minerals represents an important part of total iron content. This suggests that, regarding dissolution processes in sea water, total elemental iron content of aeolian dust can not be used directly to calculate the flux of iron available. Secondly, our results show that the free iron content vary according to the origin of dusts. Niger samples have contents in free iron of 4.4 % (SD = 0.8) for local erosion and 2.8 % (SD = 1.0) for Harmattan. Chinese samples contain 3.7 % (SD = 0.5) of free iron. These differences could be linked to the parent soil mineralogical composition that varies with geographical location, but for some of our samples it also could be linked to a size fractionation process occurring first

  1. A chameleon catalyst for nonheme iron-promoted olefin oxidation.

    PubMed

    Iyer, Shyam R; Javadi, Maedeh Moshref; Feng, Yan; Hyun, Min Young; Oloo, Williamson N; Kim, Cheal; Que, Lawrence

    2014-11-18

    We report the chameleonic reactivity of two nonheme iron catalysts for olefin oxidation with H2O2 that switch from nearly exclusive cis-dihydroxylation of electron-poor olefins to the exclusive epoxidation of electron-rich olefins upon addition of acetic acid. This switching suggests a common precursor to the nucleophilic oxidant proposed to Fe(III)-η(2)-OOH and electrophilic oxidant proposed to Fe(V)(O)(OAc), and reversible coordination of acetic acid as a switching pathway.

  2. Iron oxide and gold nanoparticles in cancer therapy

    NASA Astrophysics Data System (ADS)

    Gotman, Irena; Psakhie, Sergey G.; Lozhkomoev, Aleksandr S.; Gutmanas, Elazar Y.

    2016-08-01

    Continuous research activities in the field of nanomedicine in the past decade have, to a great extent, been focused on nanoparticle technologies for cancer therapy. Gold and iron oxide nanoparticles (NP) are two of the most studied inorganic nanomaterials due to their unique optical and magnetic properties. Both types of NPs are emerging as promising systems for anti-tumor drug delivery and for nanoparticle-mediated thermal therapy of cancer. In thermal therapy, localized heating inside tumors or in proximity of tumor cells can be induced, for example, with Au NPs by radiofrequency ablation heating or conversion of photon energy (photothermal therapy) and in iron oxide magnetic NPs by heat generation through relaxation in an alternating magnetic field (magnetic hyperthermia). Furthermore, the superparamagnetic properties of iron oxide nanoparticles have led to their use as potent MRI (magnetic resonance imaging) contrast agents. Surface modification/coating can produce NPs with tailored and desired properties, such as enhanced blood circulation time, stability, biocompatibility and water solubility. To target nanoparticles to specific tumor cells, NPs should be conjugated with targeting moieties on the surface which bind to receptors or other molecular structures on the cell surface. The article presents several approaches to enhancing the specificity of Au and iron oxide nanoparticles for tumor tissue by appropriate surface modification/functionalization, as well as the effect of these treatments on the saturation magnetization value of iron oxide NPs. The use of other nanoparticles and nanostructures in cancer treatment is also briefly reviewed.

  3. Targeted iron oxide nanoparticles for the enhancement of radiation therapy.

    PubMed

    Hauser, Anastasia K; Mitov, Mihail I; Daley, Emily F; McGarry, Ronald C; Anderson, Kimberly W; Hilt, J Zach

    2016-10-01

    To increase the efficacy of radiation, iron oxide nanoparticles can be utilized for their ability to produce reactive oxygen species (ROS). Radiation therapy promotes leakage of electrons from the electron transport chain and leads to an increase in mitochondrial production of the superoxide anion which is converted to hydrogen peroxide by superoxide dismutase. Iron oxide nanoparticles can then catalyze the reaction from hydrogen peroxide to the highly reactive hydroxyl radical. Therefore, the overall aim of this project was to utilize iron oxide nanoparticles conjugated to a cell penetrating peptide, TAT, to escape lysosomal encapsulation after internalization by cancer cells and catalyze hydroxyl radical formation. It was determined that TAT functionalized iron oxide nanoparticles and uncoated iron oxide nanoparticles resulted in permeabilization of the lysosomal membranes. Additionally, mitochondrial integrity was compromised when A549 cells were treated with both TAT-functionalized nanoparticles and radiation. Pre-treatment with TAT-functionalized nanoparticles also significantly increased the ROS generation associated with radiation. A long term viability study showed that TAT-functionalized nanoparticles combined with radiation resulted in a synergistic combination treatment. This is likely due to the TAT-functionalized nanoparticles sensitizing the cells to subsequent radiation therapy, because the nanoparticles alone did not result in significant toxicities. PMID:27521615

  4. Magnetic composites based on hybrid spheres of aluminum oxide and superparamagnetic nanoparticles of iron oxides

    NASA Astrophysics Data System (ADS)

    Braga, Tiago P.; Vasconcelos, Igor F.; Sasaki, José M.; Fabris, J. D.; de Oliveira, Diana Q. L.; Valentini, Antoninho

    2010-03-01

    Materials containing hybrid spheres of aluminum oxide and superparamagnetic nanoparticles of iron oxides were obtained from a chemical precursor prepared by admixing chitosan and iron and aluminum hydroxides. The oxides were first characterized with scanning electron microscopy, X-ray diffraction, and Mössbauer spectroscopy. Scanning electron microscopy micrographs showed the size distribution of the resulting spheres to be highly homogeneous. The occurrence of nano-composites containing aluminum oxides and iron oxides was confirmed from powder X-ray diffraction patterns; except for the sample with no aluminum, the superparamagnetic relaxation due to iron oxide particles were observed from Mössbauer spectra obtained at 298 and 110 K; the onset six line-spectrum collected at 20 K indicates a magnetic ordering related to the blocking relaxation effect for significant portion of small spheres in the sample with a molar ratio Al:Fe of 2:1.

  5. Development and use of iron oxide nanoparticles (Part 1): Synthesis of iron oxide nanoparticles for MRI

    PubMed Central

    Lodhia, J; Mandarano, G; Ferris, NJ; Eu, P; Cowell, SF

    2010-01-01

    Contrast agents, such as iron oxide, enhance MR images by altering the relaxation times of tissues in which the agent is present. They can also be used to label targeted molecular imaging probes. Unfortunately, no molecular imaging probe is currently available on the clinical MRI market. A promising platform for MRI contrast agent development is nanotechnology, where superparamagnetic iron oxide nanoparticles (SPIONS) are tailored for MR contrast enhancement, and/or for molecular imaging. SPIONs can be produced using a range of methods and the choice of method will be influenced by the characteristics most important for a particular application. In addition, the ability to attach molecular markers to SPIONS heralds their application in molecular imaging. There are many reviews on SPION synthesis for MRI; however, these tend to be targeted to a chemistry audience. The development of MRI contrast agents attracts experienced researchers from many fields including some researchers with little knowledge of medical imaging or MRI. This situation presents medical radiation practitioners with opportunities for involvement, collaboration or leadership in research depending on their level of commitment and their ability to learn. Medical radiation practitioners already possess a large portion of the understanding, knowledge and skills necessary for involvement in MRI development and molecular imaging. Their expertise in imaging technology, patient care and radiation safety provides them with skills that are directly applicable to research on the development and application of SPIONs and MRI. In this paper we argue that MRI SPIONs, currently limited to major research centres, will have widespread clinical use in the future. We believe that knowledge about this growing area of research provides an opportunity for medical radiation practitioners to enhance their specialised expertise to ensure best practice in a truly multi-disciplinary environment. This review outlines how and

  6. A pentanuclear iron catalyst designed for water oxidation

    NASA Astrophysics Data System (ADS)

    Okamura, Masaya; Kondo, Mio; Kuga, Reiko; Kurashige, Yuki; Yanai, Takeshi; Hayami, Shinya; Praneeth, Vijayendran K. K.; Yoshida, Masaki; Yoneda, Ko; Kawata, Satoshi; Masaoka, Shigeyuki

    2016-02-01

    Although the oxidation of water is efficiently catalysed by the oxygen-evolving complex in photosystem II (refs 1 and 2), it remains one of the main bottlenecks when aiming for synthetic chemical fuel production powered by sunlight or electricity. Consequently, the development of active and stable water oxidation catalysts is crucial, with heterogeneous systems considered more suitable for practical use and their homogeneous counterparts more suitable for targeted, molecular-level design guided by mechanistic understanding. Research into the mechanism of water oxidation has resulted in a range of synthetic molecular catalysts, yet there remains much interest in systems that use abundant, inexpensive and environmentally benign metals such as iron (the most abundant transition metal in the Earth’s crust and found in natural and synthetic oxidation catalysts). Water oxidation catalysts based on mononuclear iron complexes have been explored, but they often deactivate rapidly and exhibit relatively low activities. Here we report a pentanuclear iron complex that efficiently and robustly catalyses water oxidation with a turnover frequency of 1,900 per second, which is about three orders of magnitude larger than that of other iron-based catalysts. Electrochemical analysis confirms the redox flexibility of the system, characterized by six different oxidation states between FeII5 and FeIII5; the FeIII5 state is active for oxidizing water. Quantum chemistry calculations indicate that the presence of adjacent active sites facilitates O-O bond formation with a reaction barrier of less than ten kilocalories per mole. Although the need for a high overpotential and the inability to operate in water-rich solutions limit the practicality of the present system, our findings clearly indicate that efficient water oxidation catalysts based on iron complexes can be created by ensuring that the system has redox flexibility and contains adjacent water-activation sites.

  7. Bacterial oxidation of ferrous iron at low temperatures.

    PubMed

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

    2007-08-15

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

  8. Evidence of cell surface iron speciation of acidophilic iron-oxidizing microorganisms in indirect bioleaching process.

    PubMed

    Nie, Zhen-yuan; Liu, Hong-chang; Xia, Jin-lan; Yang, Yi; Zhen, Xiang-jun; Zhang, Li-Juan; Qiu, Guan-zhou

    2016-02-01

    While indirect model has been widely accepted in bioleaching, but the evidence of cell surface iron speciation has not been reported. In the present work the iron speciation on the cell surfaces of four typically acidophilic iron-oxidizing microorganism (mesophilic Acidithiobacillus ferrooxidans ATCC 23270, moderately thermophilic Leptospirillum ferriphilum YSK and Sulfobacillus thermosulfidooxidans St, and extremely thermophilic Acidianus manzaensis YN25) grown on different energy substrates (chalcopyrite, pyrite, ferrous sulfate and elemental sulfur (S(0))) were studied in situ firstly by using synchrotron-based micro- X-ray fluorescence analysis and X-ray absorption near-edge structure spectroscopy. Results showed that the cells grown on iron-containing substrates had apparently higher surface iron content than the cells grown on S(0). Both ferrous iron and ferric iron were detected on the cell surface of all tested AIOMs, and the Fe(II)/Fe(III) ratios of the same microorganism were affected by different energy substrates. The iron distribution and bonding state of single cell of A. manzaensis were then studied in situ by scanning transmission soft X-ray microscopy based on dual-energy contrast analysis and stack analysis. Results showed that the iron species distributed evenly on the cell surface and bonded with amino, carboxyl and hydroxyl groups.

  9. Purification of Lysosomes Using Supraparamagnetic Iron Oxide Nanoparticles (SPIONs).

    PubMed

    Rofe, Adam P; Pryor, Paul R

    2016-04-01

    Lysosomes can be rapidly isolated from tissue culture cells using supraparamagnetic iron oxide particles (SPIONs). In this protocol, colloidal iron dextran (FeDex) particles, a type of SPION, are taken up by cultured mouse macrophage cells via the endocytic pathway. The SPIONs accumulate in lysosomes, the end point of the endocytic pathway, permitting the lysosomes to be isolated magnetically. The purified lysosomes are suitable for in vitro fusion assays or for proteomic analysis. PMID:27037068

  10. Purification of Lysosomes Using Supraparamagnetic Iron Oxide Nanoparticles (SPIONs).

    PubMed

    Rofe, Adam P; Pryor, Paul R

    2016-04-01

    Lysosomes can be rapidly isolated from tissue culture cells using supraparamagnetic iron oxide particles (SPIONs). In this protocol, colloidal iron dextran (FeDex) particles, a type of SPION, are taken up by cultured mouse macrophage cells via the endocytic pathway. The SPIONs accumulate in lysosomes, the end point of the endocytic pathway, permitting the lysosomes to be isolated magnetically. The purified lysosomes are suitable for in vitro fusion assays or for proteomic analysis.

  11. Safety assessment of chronic oral exposure to iron oxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Chamorro, Susana; Gutiérrez, Lucía; Vaquero, María Pilar; Verdoy, Dolores; Salas, Gorka; Luengo, Yurena; Brenes, Agustín; José Teran, Francisco

    2015-05-01

    Iron oxide nanoparticles with engineered physical and biochemical properties are finding a rapidly increasing number of biomedical applications. However, a wide variety of safety concerns, especially those related to oral exposure, still need to be addressed for iron oxide nanoparticles in order to reach clinical practice. Here, we report on the effects of chronic oral exposure to low doses of γ-Fe2O3 nanoparticles in growing chickens. Animal observation, weight, and diet intake reveal no adverse signs, symptoms, or mortality. No nanoparticle accumulation was observed in liver, spleen, and duodenum, with feces as the main excretion route. Liver iron level and duodenal villi morphology reflect the bioavailability of the iron released from the partial transformation of γ-Fe2O3 nanoparticles in the acid gastric environment. Duodenal gene expression studies related to the absorption of iron from γ-Fe2O3 nanoparticles indicate the enhancement of a ferric over ferrous pathway supporting the role of mucins. Our findings reveal that oral administration of iron oxide nanoparticles is a safe route for drug delivery at low nanoparticle doses.

  12. Virus-Templated Near-Amorphous Iron Oxide Nanotubes.

    PubMed

    Shah, Sachin N; Khan, Abid A; Espinosa, Ana; Garcia, Miguel A; Nuansing, Wiwat; Ungureanu, Mariana; Heddle, Jonathan G; Chuvilin, Andrey L; Wege, Christina; Bittner, Alexander M

    2016-06-14

    We present a simple synthesis of iron oxide nanotubes, grown under very mild conditions from a solution containing Fe(II) and Fe(III), on rod-shaped tobacco mosaic virus templates. Their well-defined shape and surface chemistry suggest that these robust bionanoparticles are a versatile platform for synthesis of small, thin mineral tubes, which was achieved efficiently. Various characterization tools were used to explore the iron oxide in detail: Electron microscopy (SEM, TEM), magnetometry (SQUID-VSM), diffraction (XRD, TEM-SAED), electron spectroscopies (EELS, EDX, XPS), and X-ray absorption (XANES with EXAFS analysis). They allowed determination of the structure, crystallinity, magnetic properties, and composition of the tubes. The protein surface of the viral templates was crucial to nucleate iron oxide, exhibiting analogies to biomineralization in natural compartments such as ferritin cages. PMID:27181278

  13. Virus-Templated Near-Amorphous Iron Oxide Nanotubes.

    PubMed

    Shah, Sachin N; Khan, Abid A; Espinosa, Ana; Garcia, Miguel A; Nuansing, Wiwat; Ungureanu, Mariana; Heddle, Jonathan G; Chuvilin, Andrey L; Wege, Christina; Bittner, Alexander M

    2016-06-14

    We present a simple synthesis of iron oxide nanotubes, grown under very mild conditions from a solution containing Fe(II) and Fe(III), on rod-shaped tobacco mosaic virus templates. Their well-defined shape and surface chemistry suggest that these robust bionanoparticles are a versatile platform for synthesis of small, thin mineral tubes, which was achieved efficiently. Various characterization tools were used to explore the iron oxide in detail: Electron microscopy (SEM, TEM), magnetometry (SQUID-VSM), diffraction (XRD, TEM-SAED), electron spectroscopies (EELS, EDX, XPS), and X-ray absorption (XANES with EXAFS analysis). They allowed determination of the structure, crystallinity, magnetic properties, and composition of the tubes. The protein surface of the viral templates was crucial to nucleate iron oxide, exhibiting analogies to biomineralization in natural compartments such as ferritin cages.

  14. Eyelid allergic contact dermatitis to black iron oxide.

    PubMed

    Saxena, M; Warshaw, E; Ahmed, D D

    2001-03-01

    Eye cosmetics are a common cause of eyelid dermatitis. These products contain pigments, fragrances, resins, preservatives and vehicles. Mascara might cause either irritant or allergic contact dermatitis (ACD) of the eyelids. We present the case of a 44-year-old woman with a 10-month history of periorbital and eyelid dermatitis. Epicutaneous patch testing using the TRUE Test, cosmetic series, steroid series, and her personal products yielded a strong reaction to her mascara. Subsequent patch testing to the mascara components provided by the manufacturer revealed a severe reaction only to 5% black iron oxide. This black iron oxide was further tested in 10 normal controls with no reactions produced. There is only one previous report of eyelid ACD secondary to iron oxide that represents a rare cause of eyelid ACD.

  15. Development of Novel Biopolymer/Synthetic-Polymer/Iron Oxide Nanocomposites

    NASA Astrophysics Data System (ADS)

    Mena Montoya, Marleth; Carranza, Sugeheidy; Hinojosa, Moisés; González, Virgilio

    2009-03-01

    In this work we report the successful development of a family of magnetic nanocomposites based on chitosan or/and polyamide 6 matrix with dispersed iron oxide nanoparticles synthesized by chemical co-precipitation. The iron oxide contents varied from 5 up to 23 wt%, the nanocomposites were studied by FTIR, UV-vis, TGA, XRD, TEM and magnetometry. The FTIR analysis demonstrates an interaction between the amide group of the polyamide 6 and the ceramic material. In formic acid, the nanocomposites absorb in the UV-Vis range, and the magnitude of the band gap (optical), calculated using the band of higher wavelength, is between 2.16 and 2.19 eV. In nanocomposites with chitosan/polyamide 6 matrix the developed morphologies are spherulites of polyamide 6 surrounded by chitosan, with the iron oxide particles presumably in the form of ferrihidryte. The measured magnetic properties revealed a superparamagnetic character on the studied specimens.

  16. Imaging circulating cells and lymphoid tissues with iron oxide nanoparticles.

    PubMed

    Elias, Andrew; Tsourkas, Andrew

    2009-01-01

    The use of nanometer-sized iron oxide nanoparticles and micron-sized iron oxide particles as magnetic resonance (MR) contrast agents has garnered a high degree of interest in diverse areas of biology and medicine. Applications such as cell tracking, molecular imaging, gene detection, and lymphography are being explored to provide insight into disease mechanisms, monitor therapeutic efficacy, and facilitate diagnostic imaging. What makes iron oxide so appealing is a number of favorable properties including high detectability by MR, biodegradability and low toxicity. Here we describe the recent progress on the use of magnetic nanoparticles in imaging circulating cells and lymphoid tissues. The study of the lymph system and the biodistribution of various circulating immune cells is important in the diagnosis, prognosis, and treatment of a wide range of diseases and is expected to have a profound effect on patient outcome.

  17. Visualization study on sedimentation of micron iron oxide particles.

    PubMed

    Chen, Jin-Fang; Luo, Ye; Xu, Jun-Hui; Chen, Qi-Ming; Guo, Jia

    2006-09-15

    In this paper, a novel technique combined light-electronic microscopy and computer imaging trace was used for visualization of the sedimentation of micron iron oxide particles in a customized micro-reactor. Micron iron oxide particles were recovered from the cinder of sulfuric acid production by sedimentation separating and hydraulic rating. Effects of particle size, shape and surface roughness on the sedimentation velocity were investigated. For irregular-shape particles, the sedimentation velocity and the geometric parameters of the particles were measured by the imaging trace technique. A correction coefficient (c) was used to modify the Stokes equation. In this study, the relationship between the correction coefficient and the equivalent diameter (d(p)) was found to be linear: c=0.6272-0.0298d(p), for iron oxide particles with equivalent diameter 4-22 microm.

  18. The role of iron in prostaglandin synthesis: ferrous iron mediated oxidation of arachidonic acid.

    PubMed

    Rao, G H; Gerrard, J M; Eaton, J W; White, J G

    1978-07-01

    Arachidonic acid (AA) is the essential substrate for production of platelet endoperoxides and thromboxanes. Iron or heme is an essential cofactor for the peroxidase, lipoxygenase and cyclo-oxygenase enzymes involved in formation of these products. The present study has examined the direct interactions between iron and arachidonic acid. Iron caused the oxidation of AA into more polar products which could be detected by UV absorbtion at 232 nM or the thiobarbituric acid (TBA) reaction. High pressure liquid chromatography, chem-ionization and electron-impact mass spectrometry and nuclear magnetic resonance spectroscopy suggest that the major product was a hydroperoxide of AA. Ferrous iron (Fe++) and oxygen were absolute requirements. Fe++ was converted to the ferric iron (Fe+++) state during oxidation of AA, but Fe+++ could not substitute for Fe++. No other enzymes, cofactors or ions were involved. Conversion of AA to a hydroperoxide by Fe++ was inhibited by the antioxidant, 2, (3)-Tert-butyl-4-hydroxyanisole, the radical scavenger, nitroblue tetrazolium, and iron chelating agents, including EDTA, imidazole and dihydroxybenzoic acid. The reaction was not affected by superoxide dismutase, catalase or aspirin. These findings and preliminary studies of the Fe++ induced oxidation product of AA as a substrate for prostaglandin synthesis and inhibitor of prostacyclin production indicate the critical role of Fe++ in AA activation.

  19. Electrolytic photodissociation of chemical compounds by iron oxide photochemical diodes

    DOEpatents

    Somorjai, Gabor A.; Leygraf, Christofer H.

    1985-01-01

    Chemical compounds can be dissociated by contacting the same with a p/n type semi-conductor photochemical diode having visible light as its sole source of energy. The photochemical diode consists of low cost, readily available materials, specifically polycrystalline iron oxide doped with silicon in the case of the n-type semi-conductor electrode, and polycrystalline iron oxide doped with magnesium in the case of the p-type electrode. So long as the light source has an energy greater than 2.2 electron volts, no added energy source is needed to achieve dissociation.

  20. Multifunctional Iron Oxide Nanoparticles for Diagnostics, Therapy and Macromolecule Delivery

    PubMed Central

    Yen, Swee Kuan; Padmanabhan, Parasuraman; Selvan, Subramanian Tamil

    2013-01-01

    In recent years, multifunctional nanoparticles (NPs) consisting of either metal (e.g. Au), or magnetic NP (e.g. iron oxide) with other fluorescent components such as quantum dots (QDs) or organic dyes have been emerging as versatile candidate systems for cancer diagnosis, therapy, and macromolecule delivery such as micro ribonucleic acid (microRNA). This review intends to highlight the recent advances in the synthesis and application of multifunctional NPs (mainly iron oxide) in theranostics, an area used to combine therapeutics and diagnostics. The recent applications of NPs in miRNA delivery are also reviewed. PMID:24396508

  1. Electrolytic photodissociation of chemical compounds by iron oxide electrodes

    DOEpatents

    Somorjai, Gabor A.; Leygraf, Christofer H.

    1984-01-01

    Chemical compounds can be dissociated by contacting the same with a p/n type semi-conductor diode having visible light as its sole source of energy. The diode consists of low cost, readily available materials, specifically polycrystalline iron oxide doped with silicon in the case of the n-type semi-conductor electrode, and polycrystalline iron oxide doped with magnesium in the case of the p-type electrode. So long as the light source has an energy greater than 2.2 electron volts, no added energy source is needed to achieve dissociation.

  2. Recovery of iron oxide from coal fly ash

    DOEpatents

    Dobbins, Michael S.; Murtha, Marlyn J.

    1983-05-31

    A high quality iron oxide concentrate, suitable as a feed for blast and electric reduction furnaces is recovered from pulverized coal fly ash. The magnetic portion of the fly ash is separated and treated with a hot strong alkali solution which dissolves most of the silica and alumina in the fly ash, leaving a solid residue and forming a precipitate which is an acid soluble salt of aluminosilicate hydrate. The residue and precipitate are then treated with a strong mineral acid to dissolve the precipitate leaving a solid residue containing at least 90 weight percent iron oxide.

  3. Size-dependent magnetic properties of iron oxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Patsula, Vitalii; Moskvin, Maksym; Dutz, Silvio; Horák, Daniel

    2016-01-01

    Uniform iron oxide nanoparticles in the size range from 10 to 24 nm and polydisperse 14 nm iron oxide particles were prepared by thermal decomposition of Fe(III) carboxylates in the presence of oleic acid and co-precipitation of Fe(II) and Fe(III) chlorides by ammonium hydroxide followed by oxidation, respectively. While the first method produced hydrophobic oleic acid coated particles, the second one formed hydrophilic, but uncoated, nanoparticles. To make the iron oxide particles water dispersible and colloidally stable, their surface was modified with poly(ethylene glycol) and sucrose, respectively. Size and size distribution of the nanoparticles was determined by transmission electron microscopy, dynamic light scattering and X-ray diffraction. Surface of the PEG-functionalized and sucrose-modified iron oxide particles was characterized by Fourier transform infrared (FT-IR) and Raman spectroscopy and thermogravimetric analysis (TGA). Magnetic properties were measured by means of vibration sample magnetometry and specific absorption rate in alternating magnetic fields was determined calorimetrically. It was found, that larger ferrimagnetic particles showed higher heating performance than smaller superparamagnetic ones. In the transition range between superparamagnetism and ferrimagnetism, samples with a broader size distribution provided higher heating power than narrow size distributed particles of comparable mean size. Here presented particles showed promising properties for a possible application in magnetic hyperthermia.

  4. Growth Kinetics of Attached Iron-Oxidizing Bacteria

    PubMed Central

    Wichlacz, Paul L.; Unz, Richard F.

    1985-01-01

    A model of growth and substrate utilization for ferrous-iron-oxidizing bacteria attached to the disks of a rotating biological contactor was developed and tested. The model describes attached bacterial growth as a saturation function in which the rate of substrate utilization is determined by a maximum substrate oxidation rate constant (P), a half-saturation constant (Ks), and the concentration of substrate within the rotating biological contactor (S1). The maximum oxidation rate constant was proportional to flow rate, and the substrate concentration in the reactor varied with influent substrate concentration (S0). The model allowed the prediction of metabolic constants and included terms for both constant and growth-rate-dependent maintenance energies. Estimates for metabolic constants of the attached population of acidophilic, chemolithotrophic, iron-oxidizing bacteria limited by ferrous iron were: maximum specific growth rate (μmax), 1.14 h−1; half-saturation constant (Ks) for ferrous iron, 54.9 mg/liter; constant maintenance energy coefficient (m1), 0.154 h−1; growth-rate-dependent maintenance energy coefficient (m′), 0.07 h−1; maximum yield (Yg), 0.063 mg of organic nitrogen per mg of Fe(II) oxidized. PMID:16346863

  5. Deposition rates of oxidized iron on Mars

    NASA Technical Reports Server (NTRS)

    Burns, R. G.

    1993-01-01

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

  6. Unprecedented Selective Oxidation of Styrene Derivatives using a Supported Iron Oxide Nanocatalyst in Aqueous Medium

    EPA Science Inventory

    Iron oxide nanoparticles supported on mesoporous silica-type materials have been successfully utilized in the aqueous selective oxidation of alkenes under mild conditions using hydrogen peroxide as a green oxidant. Catalysts could be easily recovered after completion of the reac...

  7. Iron oxides, dissolved silica, and regulation of marine phosphate concentration

    NASA Astrophysics Data System (ADS)

    Planavsky, N.; Reinhard, C.; Lyons, T.

    2008-12-01

    Phosphorous concentrations in iron oxide-rich sediments reflect orthophosphate levels in the water column from which iron oxides precipitated. Sediment P/Fe ratios are also strongly influenced by the concentrations of dissolved species that inhibit orthophosphate-to-ferrihydrite sorption, most notably silica. It may, therefore, be possible to use P/Fe ratios in iron oxide-rich sediments to estimate past dissolved P concentrations, if one considers the evolution of the silica cycle. A compilation of Fe and P data in iron oxide-rich sediments through time reveals an increase in P/Fe ratios after the Jurassic. We propose that this trend indicates evolution of the iron-oxide phosphate removal mechanism caused by decreasing levels of sorption inhibition by dissolved silica. The large difference in P/Fe ratios in Cenozoic versus older iron-oxide rich sediments can be linked with Si drawdown caused by the proliferation of siliceous plankton in the Cretaceous. There is also a late Mesozoic or Cenozoic increase in V/Fe ratios, which provides additional evidence for lower ferrihydrite anion sorption efficiency prior to diatom radiation. P/Fe ratios in iron oxide-rich sediments from the early and middle Phanerozoic are comparable to the ratios in iron formations previously presented as evidence for an early Precambrian phosphate crisis (Bjerrum and Canfield, 2002, Nature, 417:159-162). Given the compelling evidence for higher Si concentrations in the Precambrian compared to the Phanerozoic and dissolved P concentrations comparable to modern levels throughout the Phanerozoic, the presented trend of P/Fe ratios suggests dissolved P concentrations were higher in Precambrian than Phanerozoic oceans. High dissolved P levels in the Precambrian may have been linked to inhibited carbonate fluorapatite (CFA) formation as a result of persistently high levels of carbonate supersaturation. Carbonate ion substitution into CFA scales with the ambient carbonate ion activity and increases

  8. Magnetic resonance imaging contrast of iron oxide nanoparticles developed for hyperthermia is dominated by iron content

    PubMed Central

    Wabler, Michele; Zhu, Wenlian; Hedayati, Mohammad; Attaluri, Anilchandra; Zhou, Haoming; Mihalic, Jana; Geyh, Alison; DeWeese, Theodore L.; Ivkov, Robert; Artemov, Dmitri

    2015-01-01

    Purpose Magnetic iron oxide nanoparticles (MNPs) are used as contrast agents for magnetic resonance imaging (MRI) and hyperthermia for cancer treatment. The relationship between MRI signal intensity and cellular iron concentration for many new formulations, particularly MNPs having magnetic properties designed for heating in hyperthermia, is lacking. In this study, we examine the correlation between MRI T2 relaxation time and iron content in cancer cells loaded with various MNP formulations. Materials and methods Human prostate carcinoma DU-145 cells were loaded with starch-coated bionised nanoferrite (BNF), iron oxide (Nanomag® D-SPIO), Feridex™, and dextran-coated Johns Hopkins University (JHU) particles at a target concentration of 50 pg Fe/cell using poly-D-lysine transfection reagent. T2-weighted MRI of serial dilutions of these labelled cells was performed at 9.4 T and iron content quantification was performed using inductively coupled plasma mass spectrometry (ICP-MS). Clonogenic assay was used to characterise cytotoxicity. Results No cytotoxicity was observed at twice the target intracellular iron concentration (~100 pg Fe/cell). ICP-MS revealed highest iron uptake efficiency with BNF and JHU particles, followed by Feridex and Nanomag-D-SPIO, respectively. Imaging data showed a linear correlation between increased intracellular iron concentration and decreased T2 times, with no apparent correlation among MNP magnetic properties. Conclusions This study demonstrates that for the range of nanoparticle concentrations internalised by cancer cells the signal intensity of T2-weighted MRI correlates closely with absolute iron concentration associated with the cells. This correlation may benefit applications for cell-based cancer imaging and therapy including nanoparticle-mediated drug delivery and hyperthermia. PMID:24773041

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

    EPA Science Inventory

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

  10. Synthesis, characterization, applications, and challenges of iron oxide nanoparticles.

    PubMed

    Ali, Attarad; Zafar, Hira; Zia, Muhammad; Ul Haq, Ihsan; Phull, Abdul Rehman; Ali, Joham Sarfraz; Hussain, Altaf

    2016-01-01

    Recently, iron oxide nanoparticles (NPs) have attracted much consideration due to their unique properties, such as superparamagnetism, surface-to-volume ratio, greater surface area, and easy separation methodology. Various physical, chemical, and biological methods have been adopted to synthesize magnetic NPs with suitable surface chemistry. This review summarizes the methods for the preparation of iron oxide NPs, size and morphology control, and magnetic properties with recent bioengineering, commercial, and industrial applications. Iron oxides exhibit great potential in the fields of life sciences such as biomedicine, agriculture, and environment. Nontoxic conduct and biocompatible applications of magnetic NPs can be enriched further by special surface coating with organic or inorganic molecules, including surfactants, drugs, proteins, starches, enzymes, antibodies, nucleotides, nonionic detergents, and polyelectrolytes. Magnetic NPs can also be directed to an organ, tissue, or tumor using an external magnetic field for hyperthermic treatment of patients. Keeping in mind the current interest in iron NPs, this review is designed to report recent information from synthesis to characterization, and applications of iron NPs. PMID:27578966

  11. Synthesis, characterization, applications, and challenges of iron oxide nanoparticles

    PubMed Central

    Ali, Attarad; Zafar, Hira; Zia, Muhammad; ul Haq, Ihsan; Phull, Abdul Rehman; Ali, Joham Sarfraz; Hussain, Altaf

    2016-01-01

    Recently, iron oxide nanoparticles (NPs) have attracted much consideration due to their unique properties, such as superparamagnetism, surface-to-volume ratio, greater surface area, and easy separation methodology. Various physical, chemical, and biological methods have been adopted to synthesize magnetic NPs with suitable surface chemistry. This review summarizes the methods for the preparation of iron oxide NPs, size and morphology control, and magnetic properties with recent bioengineering, commercial, and industrial applications. Iron oxides exhibit great potential in the fields of life sciences such as biomedicine, agriculture, and environment. Nontoxic conduct and biocompatible applications of magnetic NPs can be enriched further by special surface coating with organic or inorganic molecules, including surfactants, drugs, proteins, starches, enzymes, antibodies, nucleotides, nonionic detergents, and polyelectrolytes. Magnetic NPs can also be directed to an organ, tissue, or tumor using an external magnetic field for hyperthermic treatment of patients. Keeping in mind the current interest in iron NPs, this review is designed to report recent information from synthesis to characterization, and applications of iron NPs. PMID:27578966

  12. The fate of arsenic adsorbed on iron oxides in the presence of arsenite-oxidizing bacteria.

    PubMed

    Zhang, Zhennan; Yin, Naiyi; Du, Huili; Cai, Xiaolin; Cui, Yanshan

    2016-05-01

    Arsenic (As) is a redox-active metalloid whose toxicity and mobility in soil depend on its oxidation state. Arsenite [As(III)] can be oxidized by microbes and adsorbed by minerals in the soil. However, the combined effects of these abiotic and biotic processes are not well understood. In this study, the fate of arsenic in the presence of an isolated As(III)-oxidizing bacterium (Pseudomonas sp. HN-1, 10(9) colony-forming units (CFUs)·ml(-1)) and three iron oxides (goethite, hematite, and magnetite at 1.6 g L(-1)) was determined using batch experiments. The total As adsorption by iron oxides was lower with bacteria present and was higher with iron oxides alone. The total As adsorption decreased by 78.6%, 36.0% and 79.7% for goethite, hematite and magnetite, respectively, due to the presence of bacteria. As(III) adsorbed on iron oxides could also be oxidized by Pseudomonas sp. HN-1, but the oxidation rate (1.3 μmol h(-1)) was much slower than the rate in the aqueous phase (96.2 μmol h(-1)). Therefore, the results of other studies with minerals only might overestimate the adsorptive capacity of solids in natural systems; the presence of minerals might hinder As(III) oxidation by microbes. Under aerobic conditions, in the presence of iron oxides and As(III)-oxidizing bacteria, arsenic is adsorbed onto iron oxides within the adsorption capacity, and As(V) is the primary form in the solid and aqueous phases.

  13. Nitric oxide initiates iron binding to neocuproine.

    PubMed

    Vanin, A F; Serezhenkov, V A; Malenkova, I V

    2001-04-01

    It was demonstrated that two species of paramagnetic dinitrosyl iron complex (DNIC) with neocuproine form under the following conditions: in addition of neocuproine to a solution of DNIC with phosphate; in gaseous NO treatment of a mixture of Fe(2+) + neocuproine aqueous solutions at pH 6.5-8; and in addition of Fe(2+)--citrate complex + neocuproine to a S-nitrosocysteine (cys-NO) solution. The first form of DNIC with neocuproine is characterized by an EPR signal with g-factor values of 2.087, 2.055, and 2.025, when it is recorded at 77K. At room temperature, the complex displays a symmetric singlet at g = 2.05. The second form of DNIC with neocuproine gives an EPR signal with g-factor values of 2.042, 2.02, and 2.003, which can be recorded at a low temperature only.The revealed complexes are close to DNIC with cysteine in their stability. The ability of neocuproine to bind Fe(2+) in the presence of NO with formation of paramagnetic DNICs warrants critical reevaluation of the statement that neocuproine is only able to bind Cu(+) ions. It was suggested that the observed affinity of neocuproine to iron was due to transition of Fe(2+) in DNIC with neocuproine to Fe(+). In experiments on cys-NO, it was shown that the stabilizing effect of neocuproine on this compound could be due to neocuproine binding to the iron catalyzing decomposition of cys-NO.

  14. Nitric oxide initiates iron binding to neocuproine.

    PubMed

    Vanin, A F; Serezhenkov, V A; Malenkova, I V

    2001-04-01

    It was demonstrated that two species of paramagnetic dinitrosyl iron complex (DNIC) with neocuproine form under the following conditions: in addition of neocuproine to a solution of DNIC with phosphate; in gaseous NO treatment of a mixture of Fe(2+) + neocuproine aqueous solutions at pH 6.5-8; and in addition of Fe(2+)--citrate complex + neocuproine to a S-nitrosocysteine (cys-NO) solution. The first form of DNIC with neocuproine is characterized by an EPR signal with g-factor values of 2.087, 2.055, and 2.025, when it is recorded at 77K. At room temperature, the complex displays a symmetric singlet at g = 2.05. The second form of DNIC with neocuproine gives an EPR signal with g-factor values of 2.042, 2.02, and 2.003, which can be recorded at a low temperature only.The revealed complexes are close to DNIC with cysteine in their stability. The ability of neocuproine to bind Fe(2+) in the presence of NO with formation of paramagnetic DNICs warrants critical reevaluation of the statement that neocuproine is only able to bind Cu(+) ions. It was suggested that the observed affinity of neocuproine to iron was due to transition of Fe(2+) in DNIC with neocuproine to Fe(+). In experiments on cys-NO, it was shown that the stabilizing effect of neocuproine on this compound could be due to neocuproine binding to the iron catalyzing decomposition of cys-NO. PMID:11292366

  15. Iron Kinetics and Evolution of Microbial Populations in Low-pH, Ferrous Iron-Oxidizing Bioreactors.

    PubMed

    Jones, Rose M; Johnson, D Barrie

    2016-08-01

    Iron-rich, acidic wastewaters are commonplace pollutants associated with metal and coal mining. Continuous-flow bioreactors were commissioned and tested for their capacities to oxidize ferrous iron in synthetic and actual acid mine drainage waters using (initially) pure cultures of the recently described acidophilic, iron-oxidizing heterotrophic bacterium Acidithrix ferrooxidans grown in the presence of glucose and yeast extract. The bioreactors became rapidly colonized by this bacterium, which formed macroscopic streamer growths in the flowing waters. Over 97% of ferrous iron in pH 2.0-2.2 synthetic mine water was oxidized (at up to 225 mg L(-1) h(-1)) at dilution rates (D) of 0.6 h(-1). Rates of iron oxidation decreased with pH but were still significant, with influent liquors as low as pH 1.37. When fed with actual mine water, >90% of ferrous iron was oxidized at D values of 0.4 h(-1), and microbial communities within the bioreactors changed over time, with Atx. ferrooxidans becoming increasingly displaced by the autotrophic iron-oxidizing acidophiles Ferrovum myxofaciens, Acidithiobacillus ferrivorans, and Leptospirillum ferrooxidans (which were all indigenous to the mine water), although this did not have a negative impact on net ferrous-iron oxidation. The results confirmed the potential of using a heterotrophic acidophile to facilitate the rapid commissioning of iron-oxidizing bioreactors and illustrated how microbial communities within them can evolve without compromising the performances of the bioreactors. PMID:27377871

  16. 40 CFR 721.10529 - Cobalt iron manganese oxide, carboxylic acid-modified (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Cobalt iron manganese oxide... Significant New Uses for Specific Chemical Substances § 721.10529 Cobalt iron manganese oxide, carboxylic acid... substance identified generically as cobalt iron manganese oxide, carboxylic acid-modified (PMN P-12-35)...

  17. 40 CFR 721.10529 - Cobalt iron manganese oxide, carboxylic acid-modified (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Cobalt iron manganese oxide... Significant New Uses for Specific Chemical Substances § 721.10529 Cobalt iron manganese oxide, carboxylic acid... substance identified generically as cobalt iron manganese oxide, carboxylic acid-modified (PMN P-12-35)...

  18. Iron oxidation state in hydrous rhyolites

    NASA Astrophysics Data System (ADS)

    Humphreys, M.; Brooker, R.; Fraser, D.; Smith, V. C.

    2012-12-01

    Recent studies have suggested that the Earth's mantle at subduction zones is oxidized relative to that at mid-ocean ridges. One possible origin of the oxidation is thought to be hydrous fluids, which are released into the mantle from the down-going slab during subduction. However, this is controversial; other studies have concluded that there is no intrinsic difference in oxidation state. One potential problem in determining primary oxidation states is that magmas produced by partial melting of the sub-arc mantle undergo significant degassing and crystallisation near the earth's surface, which may overprint the oxidation state of the primary melt. H2O contents of melt inclusions may be affected by partial re-equilibration. The effect of H2O on Fe oxidation state is unclear, although theoretical arguments typically predict increasing Fe3+/ΣFe during shallow degassing as a result of preferential diffusion of H2 out of the melt: FeO (m) + H2O (m) = Fe2O3 (m) + H2 (g) [1] We used XANES to measure Fe3+/Fe2+ in cylinders of rhyolitic obsidian that had been hydrated in gold capsules in cold-seal apparatus. Runs were performed at 850-900 °C under H2O-saturated conditions for short run times (20-80 minutes). Surprisingly, we find a positive correlation between Fe3+/ΣFe and H2O content of the glass. This is inconsistent with the effects of reaction [1], but can be explained by considering the acid-base properties of the hydrous melt. In particular, basic behaviour of FeO but amphoteric behaviour of Fe2O3, and changes in melt basicity relating to dissolution of H2O, can explain increasing Fe3+/Fe2+ with increasing H2O. We discuss the implications of these results for using melt compositions to infer the oxidation state of the earth's mantle.

  19. Iron oxide nanotubes synthesized via template-based electrodeposition

    NASA Astrophysics Data System (ADS)

    Lim, Jin-Hee; Min, Seong-Gi; Malkinski, Leszek; Wiley, John B.

    2014-04-01

    Considerable effort has been invested in the development of synthetic methods for the preparation iron oxide nanostructures for applications in nanotechnology. While a variety of structures have been reported, only a few studies have focused on iron oxide nanotubes. Here, we present details on the synthesis and characterization of iron oxide nanotubes along with a proposed mechanism for FeOOH tube formation. The FeOOH nanotubes, fabricated via a template-based electrodeposition method, are found to exhibit a unique inner-surface. Heat treatment of these tubes under oxidizing or reducing atmospheres can produce either hematite (α-Fe2O3) or magnetite (Fe3O4) structures, respectively. Hematite nanotubes are composed of small nanoparticles less than 20 nm in diameter and the magnetization curves and FC-ZFC curves show superparamagnetic properties without the Morin transition. In the case of magnetite nanotubes, which consist of slightly larger nanoparticles, magnetization curves show ferromagnetism with weak coercivity at room temperature, while FC-ZFC curves exhibit the Verwey transition at 125 K.Considerable effort has been invested in the development of synthetic methods for the preparation iron oxide nanostructures for applications in nanotechnology. While a variety of structures have been reported, only a few studies have focused on iron oxide nanotubes. Here, we present details on the synthesis and characterization of iron oxide nanotubes along with a proposed mechanism for FeOOH tube formation. The FeOOH nanotubes, fabricated via a template-based electrodeposition method, are found to exhibit a unique inner-surface. Heat treatment of these tubes under oxidizing or reducing atmospheres can produce either hematite (α-Fe2O3) or magnetite (Fe3O4) structures, respectively. Hematite nanotubes are composed of small nanoparticles less than 20 nm in diameter and the magnetization curves and FC-ZFC curves show superparamagnetic properties without the Morin transition

  20. Simultaneous reductive dissolution of iron oxide and oxidation of iodide in ice.

    NASA Astrophysics Data System (ADS)

    Kim, Kitae; Choi, Wonyong

    2015-04-01

    Iron is an important trace element controlling the metabolism and growth of all kinds of living species. Especially, the bio-availability of iron has been regarded as the limiting factor for primary productivity in HNLC (High Nutrients Low Chlorophyll) regions including Southern ocean. The dissolution of iron oxide provides enhanced the bio-availability of iron for phytoplankton growth. The halogen chemistry in polar regions is related to various important environmental processes such as Antarctic Ozone Depletion Event(ODE), mercury depletion, oxidative processes in atmosphere, and the formation of CCN (Cloud Condensation Nuclei). In this study, we investigated the reductive dissolution of iron oxide particles to produce Fe(II)aq and simultaneous oxidation of I- (iodide) to I3- (tri-iodide) in ice phase under UV irradiation or dark condition. The reductive generation of Fe(II)aq from iron oxides and oxidation of iodide to I3- were negligible in water but significantly accelerated in frozen solution both in the presence and absence of light. The enhanced reductive generation of Fe(II)aq and oxidative formation of I3- in ice were observed regardless of the various types of iron oxides [hematite (α-Fe2O3) maghemite (γ- Fe2O3), goethite (α-FeOOH), lepidocrocite (γ-FeOOH) and, magnetite (Fe3O4)]. We explained that the enhanced redox production of Fe(II)aq and I3- in ice is contributed to the freeze concentration of iodides, protons, and dissolved oxygen in the unfrozen solution. When the concentration of both iodides and protons were raised by 10-fold each, the formation of Fe(II)aq in water under UV irradiation was approached to those in ice. The outdoor experiments were carried out under ambient solar radiation in winter season of mid-latitude (Pohang, Korea: 36°N latitude) and also confirmed that the production of Fe(II)aq via reductive dissolution of iron oxide and I3- generation via I- oxidation were enhanced in frozen solution. These results suggest that iron

  1. Selective stabilization of aliphatic organic carbon by iron oxide

    PubMed Central

    Adhikari, Dinesh; Yang, Yu

    2015-01-01

    Stabilization of organic matter in soil is important for natural ecosystem to sequestrate carbon and mitigate greenhouse gas emission. It is largely unknown what factors govern the preservation of organic carbon in soil, casting shadow on predicting the response of soil to climate change. Iron oxide was suggested as an important mineral preserving soil organic carbon. However, ferric minerals are subject to reduction, potentially releasing iron and decreasing the stability of iron-bound organic carbon. Information about the stability of iron-bound organic carbon in the redox reaction is limited. Herein, we investigated the sorptive interactions of organic matter with hematite and reductive release of hematite-bound organic matter. Impacts of organic matter composition and conformation on its sorption by hematite and release during the reduction reaction were analyzed. We found that hematite-bound aliphatic carbon was more resistant to reduction release, although hematite preferred to sorb more aromatic carbon. Resistance to reductive release represents a new mechanism that aliphatic soil organic matter was stabilized by association with iron oxide. Selective stabilization of aliphatic over aromatic carbon can greatly contribute to the widely observed accumulation of aliphatic carbon in soil, which cannot be explained by sorptive interactions between minerals and organic matter. PMID:26061259

  2. Selective stabilization of aliphatic organic carbon by iron oxide.

    PubMed

    Adhikari, Dinesh; Yang, Yu

    2015-01-01

    Stabilization of organic matter in soil is important for natural ecosystem to sequestrate carbon and mitigate greenhouse gas emission. It is largely unknown what factors govern the preservation of organic carbon in soil, casting shadow on predicting the response of soil to climate change. Iron oxide was suggested as an important mineral preserving soil organic carbon. However, ferric minerals are subject to reduction, potentially releasing iron and decreasing the stability of iron-bound organic carbon. Information about the stability of iron-bound organic carbon in the redox reaction is limited. Herein, we investigated the sorptive interactions of organic matter with hematite and reductive release of hematite-bound organic matter. Impacts of organic matter composition and conformation on its sorption by hematite and release during the reduction reaction were analyzed. We found that hematite-bound aliphatic carbon was more resistant to reduction release, although hematite preferred to sorb more aromatic carbon. Resistance to reductive release represents a new mechanism that aliphatic soil organic matter was stabilized by association with iron oxide. Selective stabilization of aliphatic over aromatic carbon can greatly contribute to the widely observed accumulation of aliphatic carbon in soil, which cannot be explained by sorptive interactions between minerals and organic matter. PMID:26061259

  3. Oxidation, carburization and/or sulfidation resistant iron aluminide alloy

    DOEpatents

    Sikka, Vinod K.; Deevi, Seetharama C.; Fleischhauer, Grier S.; Hajaligol, Mohammad R.; Lilly, Jr., A. Clifton

    2003-08-19

    The invention relates generally to aluminum containing iron-base alloys useful as electrical resistance heating elements. The aluminum containing iron-base alloys have improved room temperature ductility, electrical resistivity, cyclic fatigue resistance, high temperature oxidation resistance, low and high temperature strength, and/or resistance to high temperature sagging. The alloy has an entirely ferritic microstructure which is free of austenite and includes, in weight %, over 4% Al, .ltoreq.1% Cr and either .gtoreq.0.05% Zr or Zro.sub.2 stringers extending perpendicular to an exposed surface of the heating element or .gtoreq.0.1% oxide dispersoid particles. The alloy can contain 14-32% Al, .ltoreq.2% Ti, .ltoreq.2% Mo, .ltoreq.1% Zr, .ltoreq.1% C, .ltoreq.0.1% B. .ltoreq.30% oxide dispersoid and/or electrically insulating or electrically conductive covalent ceramic particles, .ltoreq.1% rare earth metal, .ltoreq.1% oxygen, .ltoreq.3% Cu, balance Fe.

  4. The Molecular Mechanism of Iron(III) Oxide Nucleation.

    PubMed

    Scheck, Johanna; Wu, Baohu; Drechsler, Markus; Rosenberg, Rose; Van Driessche, Alexander E S; Stawski, Tomasz M; Gebauer, Denis

    2016-08-18

    A molecular understanding of the formation of solid phases from solution would be beneficial for various scientific fields. However, nucleation pathways are still not fully understood, whereby the case of iron (oxyhydr)oxides poses a prime example. We show that in the prenucleation regime, thermodynamically stable solute species up to a few nanometers in size are observed, which meet the definition of prenucleation clusters. Nucleation then is not governed by a critical size, but rather by the dynamics of the clusters that are forming at the distinct nucleation stages, based on the chemistry of the linkages within the clusters. This resolves a longstanding debate in the field of iron oxide nucleation, and the results may generally apply to oxides forming via hydrolysis and condensation. The (molecular) understanding of the chemical basis of phase separation is paramount for, e.g., tailoring size, shape and structure of novel nanocrystalline materials.

  5. The Molecular Mechanism of Iron(III) Oxide Nucleation.

    PubMed

    Scheck, Johanna; Wu, Baohu; Drechsler, Markus; Rosenberg, Rose; Van Driessche, Alexander E S; Stawski, Tomasz M; Gebauer, Denis

    2016-08-18

    A molecular understanding of the formation of solid phases from solution would be beneficial for various scientific fields. However, nucleation pathways are still not fully understood, whereby the case of iron (oxyhydr)oxides poses a prime example. We show that in the prenucleation regime, thermodynamically stable solute species up to a few nanometers in size are observed, which meet the definition of prenucleation clusters. Nucleation then is not governed by a critical size, but rather by the dynamics of the clusters that are forming at the distinct nucleation stages, based on the chemistry of the linkages within the clusters. This resolves a longstanding debate in the field of iron oxide nucleation, and the results may generally apply to oxides forming via hydrolysis and condensation. The (molecular) understanding of the chemical basis of phase separation is paramount for, e.g., tailoring size, shape and structure of novel nanocrystalline materials. PMID:27466739

  6. Missing Iron-Oxidizing Acidophiles Highly Sensitive to Organic Compounds

    PubMed Central

    Ueoka, Nagayoshi; Kouzuma, Atsushi; Watanabe, Kazuya

    2016-01-01

    The genus Acidithiobacillus includes iron-oxidizing lithoautotrophs that thrive in acidic mine environments. Acidithiobacillus ferrooxidans is a representative species and has been extensively studied for its application to the bioleaching of precious metals. In our attempts to cultivate the type strain of A. ferrooxidans (ATCC 23270T), repeated transfers to fresh inorganic media resulted in the emergence of cultures with improved growth traits. Strains were isolated from the resultant culture by forming colonies on inorganic silica-gel plates. A representative isolate (strain NU-1) was unable to form colonies on agarose plates and was more sensitive to organics, such as glucose, than the type strain of A. ferrooxidans. Strain NU-1 exhibited superior growth traits in inorganic iron media to those of other iron-oxidizing acidithiobacilli, suggesting its potential for industrial applications. A draft genome of NU-1 uncovered unique features in catabolic enzymes, indicating that this strain is not a mutant of the A. ferrooxidans type strain. Our results indicate that the use of inorganic silica-gel plates facilitates the isolation of as-yet-unexamined iron-oxidizing acidithiobacilli from environmental samples and enrichment cultures. PMID:27356527

  7. Oxide Dispersion Strengthened Iron Aluminide by CVD Coated Powders

    SciTech Connect

    Asit Biswas Andrew J. Sherman

    2006-09-25

    This I &I Category2 program developed chemical vapor deposition (CVD) of iron, aluminum and aluminum oxide coated iron powders and the availability of high temperature oxidation, corrosion and erosion resistant coating for future power generation equipment and can be used for retrofitting existing fossil-fired power plant equipment. This coating will provide enhanced life and performance of Coal-Fired Boilers components such as fire side corrosion on the outer diameter (OD) of the water wall and superheater tubing as well as on the inner diameter (ID) and OD of larger diameter headers. The program also developed a manufacturing route for readily available thermal spray powders for iron aluminide coating and fabrication of net shape component by powder metallurgy route using this CVD coated powders. This coating can also be applid on jet engine compressor blade and housing, industrial heat treating furnace fixtures, magnetic electronic parts, heating element, piping and tubing for fossil energy application and automotive application, chemical processing equipment , heat exchanger, and structural member of aircraft. The program also resulted in developing a new fabrication route of thermal spray coating and oxide dispersion strengthened (ODS) iron aluminide composites enabling more precise control over material microstructures.

  8. In vivo biodistribution of iron oxide nanoparticles: an overview

    NASA Astrophysics Data System (ADS)

    Tate, Jennifer A.; Petryk, Alicia A.; Giustini, Andrew J.; Hoopes, P. Jack

    2011-03-01

    Iron oxide nanoparticles present a promising alternative to conventional energy deposition-based tissue therapies. The success of such nanoparticles as a therapeutic for diseases like cancer, however, depends heavily on the particles' ability to localize to tumor tissue as well as provide minimal toxicity to surrounding tissues and key organs such as those involved in the reticuloendothelial system (RES). We present here the results of a long term clearance study where mice injected intravenously with 2 mg Fe of 100 nm dextran-coated iron oxide nanoparticles were sacrificed at 14 and 580 days post injection. Histological analysis showed accumulation of the nanoparticles in some RES organs by the 14 day time point and clearance of the nanoparticles by the 580 day time point with no obvious toxicity to organs. An additional study reported herein employs 20 nm and 110 nm starch-coated iron oxide nanoparticles at 80 mg Fe/kg mouse in a size/biodistribution study with endpoints at 4, 24 and 72 hours. Preliminary results show nanoparticle accumulation in the liver and spleen with some elevated iron accumulation in tumoral tissues with differences between the 20 nm and the 110 nm nanoparticle depositions.

  9. The oxidation behavior of ODS iron aluminides

    SciTech Connect

    Pint, B.A.; Tortorelli, P.F.; Wright, I.G.

    1996-05-01

    Oxide-dispersed Fe-28at.%Al-2%Cr alloys were produced by a powder metallurgy technique followed by hot extrusion. A variety of stable oxides were added to the base alloy to assess the effect of these dopants on the oxidation behavior at 1200{degrees}C in air and O{sub 2}. An Al{sub 2}O{sub 3} dispersion flattened the {alpha}-Al{sub 2}O{sub 3} scale, but produced none of the other reactive element effects and had an adverse influence on the long-term oxidation behavior. A Y{sub 2}O{sub 3} dispersion improved the alumina scale adhesion relative to a Zr alloy addition at 1200{degrees} and 1300{degrees}C. However, the Y{sub 2}O{sub 3} dispersion was not as effective in improving scale adhesion in Fe{sub 3}Al as it is in FeCrAl. This inferior performance is attributed to a larger amount of interfacial void formation on ODS Fe{sub 3}Al.

  10. Composition, nucleation, and growth of iron oxide concretions

    NASA Astrophysics Data System (ADS)

    Parry, W. T.

    Iron oxide concretions are formed from post depositional, paleogroundwater chemical interaction with iron minerals in porous sedimentary rocks. The concretions record a history of iron mobilization and precipitation caused by changes in pH, oxidation conditions, and activity of bacteria. Transport limited growth rates may be used to estimate the duration of fluid flow events. The Jurassic Navajo Sandstone, an important hydrocarbon reservoir and aquifer on the Colorado Plateau, USA, is an ideal stratum to study concretions because it is widely distributed, well exposed and is the host for a variety of iron oxide concretions. Many of the concretions are nearly spherical and some consist of a rind of goethite that nearly completely fills the sandstone porosity and surrounds a central sandstone core. The interior and exterior host-rock sandstones are similar in detrital minerals, but kaolinite and interstratified illite-smectite are less abundant in the interior. Lepidocrocite is present as sand-grain rims in the exterior sandstone, but not present in the interior of the concretions. Widespread sandstone bleaching resulted from dissolution of early diagenetic hematite grain coatings by chemically reducing water that gained access to the sandstone through fault conduits. The iron was transported in solution and precipitated as iron oxide concretions by oxidation and increasing pH. Iron diffusion and advection growth time models place limits on minimum duration of the diagenetic, fluid flow events that formed the concretions. Concretion rinds 2 mm thick and 25 mm in radius would take place in 2000 years from transport by diffusion and advection and in 3600 years if transport was by diffusion only. Solid concretions 10 mm in radius would grow in 3800 years by diffusion or 2800 years with diffusion and advection. Goethite (α-FeO (OH)) and lepidocrocite (γ-FeO (OH)) nucleated on K-feldspar grains, on illite coatings on sand grains, and on pore-filling illite, but not on

  11. The reduction of iron oxides by volatiles in a rotary hearth furnace process: Part II. The reduction of iron oxide/carbon composites

    NASA Astrophysics Data System (ADS)

    Sohn, I.; Fruehan, R. J.

    2006-04-01

    The reduction of iron oxide/carbon composite pellets with hydrogen at 900 °C to 1000 °C was studied. Compared to hydrogen, the reduction by carbon was negligible at 900 °C and below. However, significant carbon oxidation of the iron oxide/graphite pellets by H2O generated from the reduction of Fe2O3 by H2 was observed. At higher temperatures, reduction by carbon complicates the overall reduction mechanism, with the iron oxide/graphite composite pellet found to be more reactive than the iron oxide/char composite pellet. From the scanning electron micrographs, partially reduced composite pellets showed a typical topochemical interface with an intermediate region between an oxygen-rich unreacted core and an iron-rich outer shell. To determine the possibility of reduction by volatiles, a layer of iron oxide powders was spread on top of a high volatile containing bituminous coal and heated inside a reactor using infra-red radiation. By separating the individual reactions involved for an iron oxide/coal mixture where a complex set of reactions occur simultaneously, it was possible to determine the sole effect of volatile reduction. It was found that the light reducing gases evolve initially and react with the iron oxide, with complex hydrocarbons evolving at the later stages. The volatiles caused about 20 to 50 pct reduction of the iron oxide.

  12. The reduction of iron oxides by volatiles in a rotary hearth furnace process: Part II. The reduction of iron oxide/carbon composites

    SciTech Connect

    Sohn, I.; Fruehan, R.J.

    2006-04-15

    The reduction of iron oxide/carbon composite pellets with hydrogen at 900{sup o}C to 1000{sup o}C was studied. Compared to hydrogen, the reduction by carbon was negligible at 900 degrees C and below. However, significant carbon oxidation of the iron oxide/graphite pellets by H{sub 2O generated from the reduction of Fe{sub 2}O{sub 3} by H-2 was observed. At higher temperatures, reduction by carbon complicates the overall reduction mechanism, with the iron oxide/graphite composite pellet found to be more reactive than the iron oxide/char composite pellet. From the scanning electron micrographs, partially reduced composite pellets showed a typical topochemical interface with an intermediate region between an oxygen-rich unreacted core and an iron-rich outer shell. To determine the possibility of reduction by volatiles, a layer of iron oxide powders was spread on top of a high volatile containing bituminous coal and heated inside a reactor using infra-red radiation. By separating the individual reactions involved for an iron oxide/coal mixture where a complex set of reactions occur simultaneously, it was possible to determine the sole effect of volatile reduction. It was found that the light reducing gases evolve initially and react with the iron oxide, with complex hydrocarbons evolving at the later stages. The volatiles caused about 20 to 50% reduction of the iron oxide.

  13. A study of the dispersity of iron oxide and iron oxide-noble metal (Me = Pd, Pt) supported systems

    NASA Astrophysics Data System (ADS)

    Cherkezova-Zheleva, Z. P.; Shopska, M. G.; Krstić, J. B.; Jovanović, D. M.; Mitov, I. G.; Kadinov, G. B.

    2007-09-01

    Samples of one-(Fe) and two-component (Fe-Pd and Fe-Pt) catalysts were prepared by incipient wetness impregnation of four different supports: TiO2 (anatase), γ-Al2O3, activated carbon, and diatomite. The chosen synthesis conditions resulted in the formation of nanosized supported phases—iron oxide (in the one-component samples), or iron oxide-noble metal (in the two-component ones). Different agglomeration degrees of these phases were obtained as a result of thermal treatment. Ultradisperse size of the supported phase was maintained in some samples, while a process of partial agglomeration occurred in others, giving rise to nearly bidisperse (ultra-and highdisperse) supported particles. The different texture of the used supports and their chemical composition are the reasons for the different stability of the nanosized supported phases. The samples were tested as heterogeneous catalysts in total benzene oxidation reaction.

  14. Intratumoral iron oxide nanoparticle hyperthermia and radiation cancer treatment

    NASA Astrophysics Data System (ADS)

    Hoopes, P. J.; Strawbridge, R. R.; Gibson, U. J.; Zeng, Q.; Pierce, Z. E.; Savellano, M.; Tate, J. A.; Ogden, J. A.; Baker, I.; Ivkov, R.; Foreman, A. R.

    2007-02-01

    The potential synergism and benefit of combined hyperthermia and radiation for cancer treatment is well established, but has yet to be optimized clinically. Specifically, the delivery of heat via external arrays /applicators or interstitial antennas has not demonstrated the spatial precision or specificity necessary to achieve appropriate a highly positive therapeutic ratio. Recently, antibody directed and possibly even non-antibody directed iron oxide nanoparticle hyperthermia has shown significant promise as a tumor treatment modality. Our studies are designed to determine the effects (safety and efficacy) of iron oxide nanoparticle hyperthermia and external beam radiation in a murine breast cancer model. Methods: MTG-B murine breast cancer cells (1 x 106) were implanted subcutaneous in 7 week-old female C3H/HeJ mice and grown to a treatment size of 150 mm3 +/- 50 mm3. Tumors were then injected locally with iron oxide nanoparticles and heated via an alternating magnetic field (AMF) generator operated at approximately 160 kHz and 400 - 550 Oe. Tumor growth was monitored daily using standard 3-D caliper measurement technique and formula. specific Mouse tumors were heated using a cooled, 36 mm diameter square copper tube induction coil which provided optimal heating in a 1 cm wide region in the center of the coil. Double dextran coated 80 nm iron oxide nanoparticles (Triton Biosystems) were used in all studies. Intra-tumor, peri-tumor and rectal (core body) temperatures were continually measured throughout the treatment period. Results: Preliminary in vivo nanoparticle-AMF hyperthermia (167 KHz and 400 or 550 Oe) studies demonstrated dose responsive cytotoxicity which enhanced the effects of external beam radiation. AMF associated eddy currents resulted in nonspecific temperature increases in exposed tissues which did not contain nanoparticles, however these effects were minor and not injurious to the mice. These studies also suggest that iron oxide nanoparticle

  15. Curcumin Attenuates Iron Accumulation and Oxidative Stress in the Liver and Spleen of Chronic Iron-Overloaded Rats

    PubMed Central

    Badria, Farid A.; Ibrahim, Ahmed S.; Badria, Adel F.; Elmarakby, Ahmed A.

    2015-01-01

    Objectives Iron overload is now recognized as a health problem in industrialized countries, as excessive iron is highly toxic for liver and spleen. The potential use of curcumin as an iron chelator has not been clearly identified experimentally in iron overload condition. Here, we evaluate the efficacy of curcumin to alleviate iron overload-induced hepatic and splenic abnormalities and to gain insight into the underlying mechanisms. Design and Methods Three groups of male adult rats were treated as follows: control rats, rats treated with iron in a drinking water for 2 months followed by either vehicle or curcumin treatment for 2 more months. Thereafter, we studied the effects of curcumin on iron overload-induced lipid peroxidation and anti-oxidant depletion. Results Treatment of iron-overloaded rats with curcumin resulted in marked decreases in iron accumulation within liver and spleen. Iron-overloaded rats had significant increases in malonyldialdehyde (MDA), a marker of lipid peroxidation and nitric oxide (NO) in liver and spleen when compared to control group. The effects of iron overload on lipid peroxidation and NO levels were significantly reduced by the intervention treatment with curcumin (P<0.05). Furthermore, the endogenous anti-oxidant activities/levels in liver and spleen were also significantly decreased in chronic iron overload and administration of curcumin restored the decrease in the hepatic and splenic antioxidant activities/levels. Conclusion Our study suggests that curcumin may represent a new horizon in managing iron overload-induced toxicity as well as in pathological diseases characterized by hepatic iron accumulation such as thalassemia, sickle cell anemia, and myelodysplastic syndromes possibly via iron chelation, reduced oxidative stress derived lipid peroxidation and improving the body endogenous antioxidant defense mechanism. PMID:26230491

  16. Radiation induced chemical activity at iron and copper oxide surfaces

    NASA Astrophysics Data System (ADS)

    Reiff, Sarah C.

    The radiolysis of three iron oxides, two copper oxides, and aluminum oxide with varying amounts of water were performed using gamma-rays and 5 MeV 4He ions. The adsorbed water on the surfaces was characterized using temperature programmed desorption and diffuse reflectance infrared spectroscopy, which indicated that all of the oxides had chemisorbed water on the surface. Physisorbed water was observed on the Fe2O 3 and Al2O3 surfaces as well. Molecular hydrogen was produced from adsorbed water only on Fe2O3 and Al 2O3, while the other compounds did not show any hydrogen production due to the low amounts of water on the surfaces. Slurries of varying amounts of water were also examined for hydrogen production, and they showed yields that were greater than the yield for bulk water. However, the yields of hydrogen from the copper compounds were much lower than those of the iron suggesting that the copper oxides are relatively inert to radiation induced damage to nearby water. X-ray diffraction measurements did not show any indication of changes to the bulk crystal structure due to radiolysis for any of the oxides. The surfaces of the oxides were analyzed using Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). For the iron samples, FeO and Fe3O4, Raman spectroscopy revealed areas of Fe2O3 had formed following irradiation with He ions. XPS indicated the formation of a new oxygen species on the iron oxide surfaces. Raman spectroscopy of the copper oxides did not reveal any changes in the surface composition, however, XPS measurements showed a decrease in the amount of OH groups on the surface of Cu2O, while for the CuO samples the amount of OH groups were found to increase following radiolysis. Pristine Al2O3 showed the presence of a surface oxyhydroxide layer which was observed to decrease following radiolysis, consistent with the formation of molecular hydrogen.

  17. Iron-mediated anaerobic oxidation of methane in brackish coastal sediments.

    PubMed

    Egger, Matthias; Rasigraf, Olivia; Sapart, Célia J; Jilbert, Tom; Jetten, Mike S M; Röckmann, Thomas; van der Veen, Carina; Bândă, Narcisa; Kartal, Boran; Ettwig, Katharina F; Slomp, Caroline P

    2015-01-01

    Methane is a powerful greenhouse gas and its biological conversion in marine sediments, largely controlled by anaerobic oxidation of methane (AOM), is a crucial part of the global carbon cycle. However, little is known about the role of iron oxides as an oxidant for AOM. Here we provide the first field evidence for iron-dependent AOM in brackish coastal surface sediments and show that methane produced in Bothnian Sea sediments is oxidized in distinct zones of iron- and sulfate-dependent AOM. At our study site, anthropogenic eutrophication over recent decades has led to an upward migration of the sulfate/methane transition zone in the sediment. Abundant iron oxides and high dissolved ferrous iron indicate iron reduction in the methanogenic sediments below the newly established sulfate/methane transition. Laboratory incubation studies of these sediments strongly suggest that the in situ microbial community is capable of linking methane oxidation to iron oxide reduction. Eutrophication of coastal environments may therefore create geochemical conditions favorable for iron-mediated AOM and thus increase the relevance of iron-dependent methane oxidation in the future. Besides its role in mitigating methane emissions, iron-dependent AOM strongly impacts sedimentary iron cycling and related biogeochemical processes through the reduction of large quantities of iron oxides.

  18. Iron aluminide alloy container for solid oxide fuel cells

    DOEpatents

    Judkins, Roddie Reagan; Singh, Prabhakar; Sikka, Vinod Kumar

    2000-01-01

    A container for fuel cells is made from an iron aluminide alloy. The container alloy preferably includes from about 13 to about 22 weight percent Al, from about 2 to about 8 weight percent Cr, from about 0.1 to about 4 weight percent M selected from Zr and Hf, from about 0.005 to about 0.5 weight percent B or from about 0.001 to about 1 weight percent C, and the balance Fe and incidental impurities. The iron aluminide container alloy is extremely resistant to corrosion and metal loss when exposed to dual reducing and oxidizing atmospheres at elevated temperatures. The alloy is particularly useful for containment vessels for solid oxide fuel cells, as a replacement for stainless steel alloys which are currently used.

  19. Promising iron oxide-based magnetic nanoparticles in biomedical engineering.

    PubMed

    Tran, Phuong Ha-Lien; Tran, Thao Truong-Dinh; Vo, Toi Van; Lee, Beom-Jin

    2012-12-01

    For the past few decades biomedical engineering has imprinted its significant impact on the map of science through its wide applications on many other fields. An important example obviously proving this fact is the versatile application of magnetic nanoparticles in theranostics. Due to preferable properties such as biocompatibility, non-toxicity compared to other metal derivations, iron oxide-based magnetic nanoparticles was chosen to be addressed in this review. Aim of this review is to give the readers a whole working window of these magnetic nanoparticles in the current context of science. Thus, preparation of magnetic iron oxide nanoparticles with the so-far techniques, methods of characterizing the nanoparticles as well as their most recent biomedical applications will be stated.

  20. Dendronized iron oxide colloids for imaging the sentinel lymph node

    NASA Astrophysics Data System (ADS)

    Jouhannaud, J.; Garofalo, A.; Felder-Flesch, D.; Pourroy, G.

    2015-03-01

    Various methods have been used in medicine for more than one century to explore the lymphatic system. Radioactive colloids (RuS labelled with 99mTc) or/and Vital Blue dye are injected around the primary tumour and detected by means of nuclear probe or visual colour inspection respectively. The simultaneous clinical use of both markers (dye and radionuclide) improves the sensitivity of detection close to 100%. Superparamagnetic iron oxides (SPIOs) are currently receiving much attention as strong T2 weighted magnetic resonance imaging contrast agents that can be potentially used for preoperative localization of sentinel nodes, but also for peroperative detection of sentinel node using hand-held probes. In that context, we present the elaboration of dendronized iron oxide nanoparticles elaborated at the Institute of Physics and Chemistry of Materials of Strasbourg.

  1. Identification of iron oxide and hydroxide in soil clays

    NASA Astrophysics Data System (ADS)

    Taneja, S. P.; Raj, D.

    1993-04-01

    Clay fractions of soils collected at different depths from the foothills of Karbi Anglong, Assam (India), have been analysed by Mössbauer spectroscopy. Mössbauer data, recorded at room and liquid nitrogen temperatures, show the presence of iron oxide (α-Fe 2O 3, hematite) and iron oxyhydroxide (α-FeOOH, goethite) in the form of fine particles/Al-substituted. All samples exhibited strong superparamagnetism, characteristic of the fine size of the oxide particles and the effect of aluminum substitution. Both hematite and goethite are present in the lower horizon while only goethite occurs in the upper horizon. In addition, silicate clay minerals e.g. kaolinite and illite are also identified.

  2. Reflection spectra and magnetochemistry of iron oxides and natural surfaces

    NASA Technical Reports Server (NTRS)

    Wasilewski, P.

    1978-01-01

    The magnetic properties and spectral characteristics of iron oxides are distinctive. Diagnostic features in reflectance spectra (0.5 to 2.4 micron) for alpha Fe2O3, gamma Fe2O3, and FeOOH include location of Fe3(+) absorption features, intensity ratios at various wavelengths, and the curve shape between 1.2 micron and 2.4 micron. The reflection spectrum of natural rock surfaces are seldom those of the bulk rock because of weathering effects. Coatings are found to be dominated by iron oxides and clay. A simple macroscopic model of rock spectra (based on concepts of stains and coatings) is considered adequate for interpretation of LANDSAT data. The magnetic properties of materials associated with specific spectral types and systematic changes in both spectra and magnetic properties are considered.

  3. Biosynthesis of nitric oxide activates iron regulatory factor in macrophages.

    PubMed

    Drapier, J C; Hirling, H; Wietzerbin, J; Kaldy, P; Kühn, L C

    1993-09-01

    Biosynthesis of nitric oxide (NO) from L-arginine modulates activity of iron-dependent enzymes, including mitochondrial acontiase, an [Fe-S] protein. We examined the effect of NO on the activity of iron regulatory factor (IRF), a cytoplasmic protein which modulates both ferritin mRNA translation and transferrin receptor mRNA stability by binding to specific mRNA sequences called iron responsive elements (IREs). Murine macrophages were activated with interferon-gamma and lipopolysaccharide to induce NO synthase activity and cultured in the presence or absence of NG-substituted analogues of L-arginine which served as selective inhibitors of NO synthesis. Measurement of the nitrite concentration in the culture medium was taken as an index of NO production. Mitochondria-free cytosols were then prepared and aconitase activity as well as IRE binding activity and induction of IRE binding activity were correlated and depended on NO synthesis after IFN-gamma and/or LPS stimulation. Authentic NO gas as well as the NO-generating compound 3-morpholinosydnonimine (SIN-1) also conversely modulated aconitase and IRE binding activities of purified recombinant IRF. These results provide evidence that endogenously produced NO may modulate the post-transcriptional regulation of genes involved in iron homeostasis and support the hypothesis that the [Fe-S] cluster of IRF mediates iron-dependent regulation. PMID:7504626

  4. The role of iron redox state in the genotoxicity of ultrafine superparamagnetic iron oxide nanoparticles.

    PubMed

    Singh, Neenu; Jenkins, Gareth J S; Nelson, Bryant C; Marquis, Bryce J; Maffeis, Thierry G G; Brown, Andy P; Williams, Paul M; Wright, Chris J; Doak, Shareen H

    2012-01-01

    Ultrafine superparamagnetic iron oxide nanoparticles (USPION) hold great potential for revolutionising biomedical applications such as MRI, localised hyperthermia, and targeted drug delivery. Though evidence is increasing regarding the influence of nanoparticle physico-chemical features on toxicity, data however, is lacking that assesses a range of such characteristics in parallel. We show that iron redox state, a subtle though important physico-chemical feature of USPION, dramatically modifies the cellular uptake of these nanoparticles and influences their induction of DNA damage. Surface chemistry was also found to have an impact and evidence to support a potential mechanism of oxidative DNA damage behind the observed responses has been demonstrated. As human exposure to ferrofluids is predicted to increase through nanomedicine based therapeutics, these findings are important in guiding the fabrication of USPION to ensure they have characteristics that support biocompatibility. PMID:22027595

  5. Reducing arsenic accumulation in rice grain through iron oxide amendment.

    PubMed

    Farrow, Eric M; Wang, Jianmin; Burken, Joel G; Shi, Honglan; Yan, Wengui; Yang, John; Hua, Bin; Deng, Baolin

    2015-08-01

    Effects of soil-arsenic (As), phosphorus and iron oxide on As accumulation in rice grain were investigated. Cultivars that have significantly different sensitivity to As, straighthead-resistant Zhe 733 and straighthead-susceptible Cocodrie, were used to represent different cultivar varieties. The grain accumulation of other elements of concern, selenium (Se), molybdenum (Mo), and cadmium (Cd) was also monitored. Results demonstrated that high soil-As not only resulted in high grain-As, but could also result in high grain-Se, and Zhe 733 had significantly less grain-As than Cocodrie did. However, soil-As did not impact grain-Mo and Cd. Among all elements monitored, iron oxide amendment significantly reduced grain-As for both cultivars, while the phosphate application only reduced grain-Se for Zhe 733. Results also indicated that cultivar type significantly impacted grain accumulation of all monitored trace elements. Therefore, applying iron oxide to As-contaminated land, in addition to choosing appropriate rice cultivar, can effectively reduce the grain accumulation of As. PMID:25910688

  6. Electron uptake by iron-oxidizing phototrophic bacteria

    SciTech Connect

    Bose, A; Gardel, EJ; Vidoudez, C; Parra, EA; Girguis, PR

    2014-02-26

    Oxidation-reduction reactions underlie energy generation in nearly all life forms. Although most organisms use soluble oxidants and reductants, some microbes can access solid-phase materials as electron-acceptors or -donors via extracellular electron transfer. Many studies have focused on the reduction of solid-phase oxidants. Far less is known about electron uptake via microbial extracellular electron transfer, and almost nothing is known about the associated mechanisms. Here we show that the iron-oxidizing photoautotroph Rhodopseudomonas palustris TIE-1 accepts electrons from a poised electrode, with carbon dioxide as the sole carbon source/electron acceptor. Both electron uptake and ruBisCo form I expression are stimulated by light. Electron uptake also occurs in the dark, uncoupled from photosynthesis. Notably, the pioABC operon, which encodes a protein system essential for photoautotrophic growth by ferrous iron oxidation, influences electron uptake. These data reveal a previously unknown metabolic versatility of photoferrotrophs to use extracellular electron transfer for electron uptake.

  7. Iron requirement for Mn(II) oxidation by Leptothrix discophora SS-1.

    PubMed

    El Gheriany, Iman A; Bocioaga, Daniela; Hay, Anthony G; Ghiorse, William C; Shuler, Michael L; Lion, Leonard W

    2009-03-01

    A common form of biocatalysis of Mn(II) oxidation results in the formation of biogenic Mn(III, IV) oxides and is a key reaction in the geochemical cycling of Mn. In this study, we grew the model Mn(II)-oxidizing bacterium Leptothrix discophora SS-1 in media with limited iron (0.1 microM iron/5.8 mM pyruvate) and sufficient iron (0.2 microM iron/5.8 mM pyruvate). The influence of iron on the rate of extracellular Mn(II) oxidation was evaluated. Cultures in which cell growth was limited by iron exhibited reduced abilities to oxidize Mn(II) compared to cultures in medium with sufficient iron. While the extracellular Mn(II)-oxidizing factor (MOF) is thought to be a putative multicopper oxidase, Mn(II) oxidation in the presence of zero added Cu(II) was detected and the decrease in the observed Mn(II) oxidation rate in iron-limited cultures was not relieved when the medium was supplemented with Cu(II). The decline of Mn(II) oxidation under iron-limited conditions was not accompanied by siderophore production and is unlikely to be an artifact of siderophore complex formation with Mn(III). The temporal variations in mofA gene transcript levels under conditions of limited and abundant iron were similar, indicating that iron limitation did not interfere with the transcription of the mofA gene. Our quantitative PCR results provide a step forward in understanding the regulation of Mn(II) oxidation. The mechanistic role of iron in Mn(II) oxidation is uncertain; the data are consistent with a direct requirement for iron as a component of the MOF or an indirect effect of iron resulting from the limitation of one of many cellular functions requiring iron. PMID:19114505

  8. Iron Requirement for Mn(II) Oxidation by Leptothrix discophora SS-1▿

    PubMed Central

    El Gheriany, Iman A.; Bocioaga, Daniela; Hay, Anthony G.; Ghiorse, William C.; Shuler, Michael L.; Lion, Leonard W.

    2009-01-01

    A common form of biocatalysis of Mn(II) oxidation results in the formation of biogenic Mn(III, IV) oxides and is a key reaction in the geochemical cycling of Mn. In this study, we grew the model Mn(II)-oxidizing bacterium Leptothrix discophora SS-1 in media with limited iron (0.1 μM iron/5.8 mM pyruvate) and sufficient iron (0.2 μM iron/5.8 mM pyruvate). The influence of iron on the rate of extracellular Mn(II) oxidation was evaluated. Cultures in which cell growth was limited by iron exhibited reduced abilities to oxidize Mn(II) compared to cultures in medium with sufficient iron. While the extracellular Mn(II)-oxidizing factor (MOF) is thought to be a putative multicopper oxidase, Mn(II) oxidation in the presence of zero added Cu(II) was detected and the decrease in the observed Mn(II) oxidation rate in iron-limited cultures was not relieved when the medium was supplemented with Cu(II). The decline of Mn(II) oxidation under iron-limited conditions was not accompanied by siderophore production and is unlikely to be an artifact of siderophore complex formation with Mn(III). The temporal variations in mofA gene transcript levels under conditions of limited and abundant iron were similar, indicating that iron limitation did not interfere with the transcription of the mofA gene. Our quantitative PCR results provide a step forward in understanding the regulation of Mn(II) oxidation. The mechanistic role of iron in Mn(II) oxidation is uncertain; the data are consistent with a direct requirement for iron as a component of the MOF or an indirect effect of iron resulting from the limitation of one of many cellular functions requiring iron. PMID:19114505

  9. Role of nitric oxide in cellular iron metabolism.

    PubMed

    Kim, Sangwon; Ponka, Prem

    2003-03-01

    Iron regulatory proteins (IRP1 and IRP2) control the synthesis of transferrin receptors (TfR) and ferritin by binding to iron-responsive elements (IREs) which are located in the 3' untranslated region (UTR) and the 5' UTR of their respective mRNAs. Cellular iron levels affect binding of IRPs to IREs and consequently expression of TfR and ferritin. Moreover, NO*, a redox species of nitric oxide that interacts primarily with iron, can activate IRP1 RNA-binding activity resulting in an increase in TfR mRNA levels. We have shown that treatment of RAW 264.7 cells (a murine macrophage cell line) with NO+ (nitrosonium ion, which causes S-nitrosylation of thiol groups) resulted in a rapid decrease in RNA-binding of IRP2, followed by IRP2 degradation, and these changes were associated with a decrease in TfR mRNA levels. Moreover, we demonstrated that stimulation of RAW 264.7 cells with lipopolysaccharide (LPS) and interferon-gamma (IFN-gamma) increased IRP1 binding activity, whereas RNA-binding of IRP2 decreased and was followed by a degradation of this protein. Furthermore, the decrease of IRP2 binding/protein levels was associated with a decrease in TfR mRNA levels in LPS/IFN-gamma-treated cells, and these changes were prevented by inhibitors of inducible nitric oxide synthase. These results suggest that NO+-mediated degradation of IRP2 plays a major role in iron metabolism during inflammation.

  10. Evaluation of Characterization Techniques for Iron Pipe Corrosion Products and Iron Oxide Thin Films

    SciTech Connect

    Borch, Thomas; Camper, Anne K.; Biederman, Joel A.; Butterfield, Phillip; Gerlach, Robin; Amonette, James E.

    2008-10-01

    A common problem faced by drinking water studies is that of properly characterizing the corrosion products (CP) in iron pipescor synthetic Fe (hydr)oxides used to simulate the iron pipe used in municipal drinking-water systems. The present work compares the relative applicability of a suite of imaging and analytical techniques for the characterization of CPs and synthetic Fe oxide thin films and provide an overview of the type of data that each instrument can provide as well as their limitations to help researchers and consultants choose the best technique for a given task. Crushed CP from a water distribution system and synthetic Fe oxide thin films formed on glass surfaces were chosen as test samples for this evaluation. The CP and synthetic Fe oxide thin films were analyzed by atomic force microscopy (AFM), scanning electron microscopy (SEM), energy-dispersive spectroscopy, time-of-flight secondary ion mass spectrometry (ToF-SIMS), X-ray powder diffractometry (XRD), grazing incident diffractometry (GID), transmission electron microscopy (TEM), selected area electron diffraction, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared, Mössbauer spectroscopy, Brunauer-Emmett-Teller N2 adsorption and Fe concentration was determined by the ferrozine method. XRD and GID were found to be the most suitable techniques for identification of the mineralogical composition of CP and synthetic Fe oxide thin films, respectively. AFM and a combined ToF-SIMS-AFM approach proved excellent for roughness and depth profiling analysis of synthetic Fe oxide thin films, respectively. Corrosion products were difficult to study by AFM due to their surface roughness, while synthetic Fe oxide thin films resisted most spectroscopic methods due to their limited thickness (118 nm). XPS analysis is not recommended for mixtures of Fe (hydr)oxides due to their spectral similarities. SEM and TEM provided great detail on mineralogical morphology.

  11. Unification of catalytic water oxidation and oxygen reduction reactions: amorphous beat crystalline cobalt iron oxides.

    PubMed

    Indra, Arindam; Menezes, Prashanth W; Sahraie, Nastaran Ranjbar; Bergmann, Arno; Das, Chittaranjan; Tallarida, Massimo; Schmeißer, Dieter; Strasser, Peter; Driess, Matthias

    2014-12-17

    Catalytic water splitting to hydrogen and oxygen is considered as one of the convenient routes for the sustainable energy conversion. Bifunctional catalysts for the electrocatalytic oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) are pivotal for the energy conversion and storage, and alternatively, the photochemical water oxidation in biomimetic fashion is also considered as the most useful way to convert solar energy into chemical energy. Here we present a facile solvothermal route to control the synthesis of amorphous and crystalline cobalt iron oxides by controlling the crystallinity of the materials with changing solvent and reaction time and further utilize these materials as multifunctional catalysts for the unification of photochemical and electrochemical water oxidation as well as for the oxygen reduction reaction. Notably, the amorphous cobalt iron oxide produces superior catalytic activity over the crystalline one under photochemical and electrochemical water oxidation and oxygen reduction conditions.

  12. New Insight into Microbial Iron Oxidation as Revealed by the Proteomic Profile of an Obligate Iron-Oxidizing Chemolithoautotroph

    PubMed Central

    Emerson, David; Sylvan, Jason B.; Orcutt, Beth N.; Jacobson Meyers, Myrna E.; Ramírez, Gustavo A.; Zhong, John D.; Edwards, Katrina J.

    2015-01-01

    Microaerophilic, neutrophilic, iron-oxidizing bacteria (FeOB) grow via the oxidation of reduced Fe(II) at or near neutral pH, in the presence of oxygen, making them relevant in numerous environments with elevated Fe(II) concentrations. However, the biochemical mechanisms for Fe(II) oxidation by these neutrophilic FeOB are unknown, and genetic markers for this process are unavailable. In the ocean, microaerophilic microorganisms in the genus Mariprofundus of the class Zetaproteobacteria are the only organisms known to chemolithoautotrophically oxidize Fe and concurrently biomineralize it in the form of twisted stalks of iron oxyhydroxides. The aim of this study was to identify highly expressed proteins associated with the electron transport chain of microaerophilic, neutrophilic FeOB. To this end, Mariprofundus ferrooxydans PV-1 was cultivated, and its proteins were extracted, assayed for redox activity, and analyzed via liquid chromatography-tandem mass spectrometry for identification of peptides. The results indicate that a cytochrome c4, cbb3-type cytochrome oxidase subunits, and an outer membrane cytochrome c were among the most highly expressed proteins and suggest an involvement in the process of aerobic, neutrophilic bacterial Fe oxidation. Proteins associated with alternative complex III, phosphate transport, carbon fixation, and biofilm formation were abundant, consistent with the lifestyle of Mariprofundus. PMID:26092463

  13. Nitric oxide-mediated modulation of iron regulatory proteins: implication for cellular iron homeostasis.

    PubMed

    Kim, Sangwon; Ponka, Prem

    2002-01-01

    Iron regulatory proteins (IRP1 and IRP2) control the synthesis of transferrin receptors (TfR) and ferritin by binding to iron-responsive elements (IREs) that are located in the 3' untranslated region (UTR) and the 5' UTR of their respective mRNAs. Cellular iron levels affect binding of IRPs to IREs and consequently expression of TfR and ferritin. Moreover, NO(.), a redox species of nitric oxide that interacts primarily with iron, can activate IRP1 RNA-binding activity resulting in an increase in TfR mRNA levels and a decrease in ferritin synthesis. We have shown that treatment of RAW 264.7 cells (a murine macrophage cell line) with NO(+) (nitrosonium ion, which causes S-nitrosylation of thiol groups) resulted in a rapid decrease in RNA-binding of IRP2, followed by IRP2 degradation, and these changes were associated with a decrease in TfR mRNA levels and a dramatic increase in ferritin synthesis. Moreover, we demonstrated that stimulation of RAW 264.7 cells with lipopolysaccharide (LPS) and interferon-gamma (IFN-gamma) increased IRP1 binding activity, whereas RNA-binding of IRP2 decreased and was followed by a degradation of this protein. Furthermore, the decrease of IRP2 binding/protein levels was associated with a decrease in TfR mRNA levels and an increase in ferritin synthesis in LPS/IFN-gamma-treated cells, and these changes were prevented by inhibitors of inducible nitric oxide synthase. These results suggest that NO(+)-mediated degradation of IRP2 plays a major role in iron metabolism during inflammation.

  14. Synthesis of superparamagnetic iron(III) oxide nanowires in double-walled carbon nanotubes.

    PubMed

    Tîlmaciu, Carmen-Mihaela; Soula, Brigitte; Galibert, Anne-Marie; Lukanov, Petar; Datas, Lucien; González, Jesús; Barquín, Luis Fernández; Rodríguez Fernández, Jesús; González-Jiménez, Fernando; Jorge, Jose; Flahaut, Emmanuel

    2009-11-21

    The synthesis and characterization of superparamagnetic iron(iii) oxide nanowires confined within double-walled carbon nanotubes by capillary filling with a melted precursor (iron iodide) followed by thermal treatment is reported for the first time.

  15. Green rust and iron oxide formation influences metolachlor dechlorination during zerovalent iron treatment.

    PubMed

    Satapanajaru, Tunlawit; Shea, Patrick J; Comfort, Steve D; Roh, Yul

    2003-11-15

    Electron transfer from zerovalent iron (Fe0) to targeted contaminants is affected by initial Fe0 composition, the oxides formed during corrosion, and surrounding electrolytes. We previously observed enhanced metolachlor destruction by Fe0 when iron or aluminum salts were present in the aqueous matrix and Eh/pH conditions favored formation of green rusts. To understand these enhanced destruction rates, we characterized changes in Fe0 composition during treatment of metolachlor with and without iron and aluminum salts. Raman microspectroscopy and X-ray diffraction (XRD) indicated that the iron source was initially coated with a thin layer of magnetite (Fe3O4), maghemite (gamma-Fe2O3), and wüstite (FeO). Time-resolved analysis indicated that akaganeite (beta-FeOOH) was the dominant oxide formed during Fe0 treatment of metolachlor. Goethite (alpha-FeOOH) and some lepidocrocite (gamma-FeOOH) formed when Al2(SO4)3 was present, while goethite and magnetite (Fe3O4) were identified in Fe0 treatments containing FeSO4. Although conditions favoring formation of sulfate green rust (GR(II); Fe6(OH)12SO4) facilitated Fe0-mediated dechlorination of metolachlor, only adsorption was observed when GR(II) was synthesized (without Fe0) in the presence of metolachlor and Eh/pH changed to favor Fe(III)oxyhydroxide or magnetite formation. In contrast, dechlorination occurred when magnetite or natural goethite was amended with Fe(II) (as FeSO4) at pH 8 and continued as long as additional Fe(II) was provided. While metolachlor was not dechlorinated by GR(II) itself during a 48-h incubation, the GR(II) provided a source of Fe(II) and produced magnetite (and other oxide surfaces) that coordinated Fe(II), which then facilitated dechlorination.

  16. Altering the structure and properties of iron oxide nanoparticles and graphene oxide/iron oxide composites by urea

    NASA Astrophysics Data System (ADS)

    Naghdi, Samira; Rhee, Kyong Yop; Jaleh, Babak; Park, Soo Jin

    2016-02-01

    Iron oxide (Fe2O3) nanoparticles were grown on graphene oxide (GO) using a simple microwave-assisted method. The effects of urea concentration on Fe2O3 nanoparticles and GO/Fe2O3 composite were examined. The as-prepared samples were characterized using X-ray powder diffraction, Raman spectroscopy, and transmission electron microscopy. The Fe2O3 nanoparticles were uniformly developed on GO sheets. The results showed that urea affects both Fe2O3 morphology and particle size. In the absence of urea, the Fe2O3 nanostructures exhibited a rod-like morphology. However, increasing urea concentration altered the morphology and decreased the particle size. The Raman results of GO/Fe2O3 showed that the intensity ratio of D band to G band (ID/IG) was decreased by addition of urea, indicating that urea can preserve the GO sheets during synthesis of the composite from exposing more defects. The surface area and thermal stability of GO/Fe2O3 and Fe2O3 were compared using the Brunauer-Emmett-Teller method and thermal gravimetric analysis, respectively. The results showed that the increased concentration of urea induced a larger surface area with more active sites in the Fe2O3 nanoparticles. However, the increase in urea concentration led to decreased thermal stability of the Fe2O3 nanoparticles. The magnetic properties of Fe2O3 nanoparticles were characterized by a vibrating sample magnetometer and results revealed that the magnetic properties of Fe2O3 nanoparticles are affected by the morphology.

  17. Mercury removal in wastewater by iron oxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Vélez, E.; Campillo, G. E.; Morales, G.; Hincapié, C.; Osorio, J.; Arnache, O.; Uribe, J. I.; Jaramillo, F.

    2016-02-01

    Mercury is one of the persistent pollutants in wastewater; it is becoming a severe environmental and public health problem, this is why nowadays its removal is an obligation. Iron oxide nanoparticles are receiving much attention due to their properties, such as: great biocompatibility, ease of separation, high relation of surface-area to volume, surface modifiability, reusability, excellent magnetic properties and relative low cost. In this experiment, Fe3O4 and γ-Fe2O3 nanoparticles were synthesized using iron salts and NaOH as precipitation agents, and Aloe Vera as stabilizing agent; then these nanoparticles were characterized by three different measurements: first, using a Zetasizer Nano ZS for their size estimation, secondly UV-visible spectroscopy which showed the existence of resonance of plasmon at λmax∼360 nm, and lastly by Scanning Electron Microscopy (SEM) to determine nanoparticles form. The results of this characterization showed that the obtained Iron oxides nanoparticles have a narrow size distribution (∼100nm). Mercury removal of 70% approximately was confirmed by atomic absorption spectroscopy measurements.

  18. Phase discrimination through oxidant selection in low-temperature atomic layer deposition of crystalline iron oxides.

    PubMed

    Riha, Shannon C; Racowski, Joy M; Lanci, Michael P; Klug, Jeffrey A; Hock, Adam S; Martinson, Alex B F

    2013-03-12

    Control over the oxidation state and crystalline phase of thin-film iron oxides was achieved by low-temperature atomic layer deposition (ALD), utilizing a novel iron precursor, bis(2,4-methylpentadienyl)iron. This low-temperature (T = 120 °C) route to conformal deposition of crystalline Fe3O4 or α-Fe2O3 thin films is determined by the choice of oxygen source selected for the second surface half-reaction. The approach employs ozone to produce fully oxidized α-Fe2O3 or a milder oxidant, H2O2, to generate the Fe(2+)/Fe(3+) spinel, Fe3O4. Both processes show self-limiting surface reactions and deposition rates of at least 0.6 Å/cycle, a significantly high growth rate at such mild conditions. We utilized this process to prepare conformal iron oxide thin films on a porous framework, for which α-Fe2O3 is active for photocatalytic water splitting.

  19. Study of nanocomposites based on iron oxides and pectin

    NASA Astrophysics Data System (ADS)

    Chistyakova, Nataliya I.; Shapkin, Alexey A.; Sirazhdinov, Ruslan R.; Gubaidulina, Tatiana V.; Kiseleva, Tatiana Yu.; Kazakov, Alexander P.; Rusakov, Vyacheslav S.

    2014-10-01

    Mössbauer and X-ray diffraction study of nanocomposites based on iron oxides and pectin (PC) was carried out involving magnetization measurements. The concentrations of PC in nanocomposites varied from 0 to 10%. Mössbauer investigations of nanocomposites were carried out in the temperature range from 5 to 300 K. Many-state superparamagnetic relaxation model was used for spectra fitting. The magnetization, M(T,H), was measured in the temperature interval of 80-300 K and magnetic field up to 10 kOe. Formation of the "iron-polymer" interface was not observed. Particle sizes were estimated using the Mössbauer and X-ray powder diffraction data.

  20. Study of nanocomposites based on iron oxides and pectin

    SciTech Connect

    Chistyakova, Nataliya I. Shapkin, Alexey A. Sirazhdinov, Ruslan R. Gubaidulina, Tatiana V. Kiseleva, Tatiana Yu. Kazakov, Alexander P. Rusakov, Vyacheslav S.

    2014-10-27

    Mössbauer and X-ray diffraction study of nanocomposites based on iron oxides and pectin (PC) was carried out involving magnetization measurements. The concentrations of PC in nanocomposites varied from 0 to 10%. Mössbauer investigations of nanocomposites were carried out in the temperature range from 5 to 300 K. Many-state superparamagnetic relaxation model was used for spectra fitting. The magnetization, M(T,H), was measured in the temperature interval of 80-300 K and magnetic field up to 10 kOe. Formation of the 'iron-polymer' interface was not observed. Particle sizes were estimated using the Mössbauer and X-ray powder diffraction data.

  1. Cobalt-promoted Iron Oxide Nanoparticles for the Selective Oxidative Dehydrogenation of Cyclohexane

    NASA Astrophysics Data System (ADS)

    Rutter, Matthew

    Recent work has shown that both cobalt and iron oxide nanoparticles are active for the oxidative dehydrogenation (ODH) of cyclohexane to benzene, the former more active than the latter. Further study has shown that the addition of gold species as a minority component into iron oxide nanocrystals increases the selectivity of the reaction to benzene. Since a primary motivation for this work is the addition of catalysts in jet fuels to facilitate the dehydrogenation and cracking reactions preceding their combustion, a low-cost, sacrificial catalyst is sought after. In this application, catalyst nanoparticles suspended in the fuel stream will dehydrogenate cyclic alkanes (cyclohexane) to their aromatic counterparts (benzene). Alkenes and aromatics have a much higher rate of combustion, which decreases the amount of uncombusted fuel in the exhaust, thereby increasing performance. As these catalysts are not recyclable, there is significant impetus to substitute cheaper base metals for expensive noble metals. In this work, iron oxide nanoparticles are doped with varying levels of cobalt to examine the effect of cobalt content and oxidation state on the selectivity and activity of the iron oxide for the oxidative dehydrogenation of cyclohexane, used as a model cyclic alkane in jet fuel. We have shown previously that small (˜5nm) cobalt oxide nanoparticles favor the production of benzene over the partial dehydrogenation products cyclohexene and cyclohexadiene, or the complete oxidation product carbon dioxide. It is the aim of this work to examine the surface of these cobalt-iron oxide nanoparticles to determine the conditions most favorable for this selective oxidative dehydrogenation. Cobalt-doped iron nanoparticles were prepared by a surfactant-free hydrothermal co-precipitation technique that enabled a high degree of composition control and size control. These samples were characterized via Transmission Electron Microscopy (TEM), powder X-Ray Diffraction (XRD), X

  2. GAS-PHASE FLAME SYNTHESIS AND PROPERTIES OF MAGNETIC IRON OXIDE NANOPARTICLES WITH REDUCED OXIDATION STATE

    PubMed Central

    Kumfer, Benjamin M; Shinoda, Kozo; Jeyadevan, Balachandran; Kennedy, Ian M

    2010-01-01

    Iron oxide nanoparticles of reduced oxidation state, mainly in the form of magnetite, have been synthesized utilizing a new continuous, gas-phase, nonpremixed flame method using hydrocarbon fuels. This method takes advantage of the characteristics of the inverse flame, which is produced by injection of oxidizer into a surrounding flow of fuel. Unlike traditional flame methods, this configuration allows for the iron particle formation to be maintained in a more reducing environment. The effects of flame temperature, oxygen-enrichment and fuel dilution (i.e. the stoichiometric mixture fraction), and fuel composition on particle size, Fe oxidation state, and magnetic properties are evaluated and discussed. The crystallite size, Fe(II) fraction, and saturation magnetization were all found to increase with flame temperature. Flames of methane and ethylene were used, and the use of ethylene resulted in particles containing metallic Fe(0), in addition to magnetite, while no Fe(0) was present in samples synthesized using methane. PMID:20228941

  3. Selective Inhibition of the Oxidation of Ferrous Iron or Sulfur in Thiobacillus ferrooxidans

    PubMed Central

    Harahuc, Lesia; Lizama, Hector M.; Suzuki, Isamu

    2000-01-01

    The oxidation of either ferrous iron or sulfur by Thiobacillus ferrooxidans was selectively inhibited or controlled by various anions, inhibitors, and osmotic pressure. Iron oxidation was more sensitive than sulfur oxidation to inhibition by chloride, phosphate, and nitrate at low concentrations (below 0.1 M) and also to inhibition by azide and cyanide. Sulfur oxidation was more sensitive than iron oxidation to the inhibitory effect of high osmotic pressure. These differences were evident not only between iron oxidation by iron-grown cells and sulfur oxidation by sulfur-grown cells but also between the iron and sulfur oxidation activities of the same iron-grown cells. Growth experiments with ferrous iron or sulfur as an oxidizable substrate confirmed the higher sensitivity of iron oxidation to inhibition by phosphate, chloride, azide, and cyanide. Sulfur oxidation was actually stimulated by 50 mM phosphate or chloride. Leaching of Fe and Zn from pyrite (FeS2) and sphalerite (ZnS) by T. ferrooxidans was differentially affected by phosphate and chloride, which inhibited the solubilization of Fe without significantly affecting the solubilization of Zn. PMID:10698768

  4. Biological iron oxidation by Gallionella spp. in drinking water production under fully aerated conditions.

    PubMed

    de Vet, W W J M; Dinkla, I J T; Rietveld, L C; van Loosdrecht, M C M

    2011-11-01

    Iron oxidation under neutral conditions (pH 6.5-8) may be a homo- or heterogeneous chemically- or a biologically-mediated process. The chemical oxidation is supposed to outpace the biological process under slightly alkaline conditions (pH 7-8). The iron oxidation kinetics and growth of Gallionella spp. - obligatory chemolithotrophic iron oxidizers - were assessed in natural, organic carbon-containing water, in continuous lab-scale reactors and full-scale groundwater trickling filters in the Netherlands. From Gallionella cell numbers determined by qPCR, balances were made for all systems. The homogeneous chemical iron oxidation occurred in accordance with the literature, but was retarded by a low water temperature (13 °C). The contribution of the heterogeneous chemical oxidation was, despite the presence of freshly formed iron oxyhydroxides, much lower than in previous studies in ultrapure water. This could be caused by the adsorption of natural organic matter (NOM) on the iron oxide surfaces. In the oxygen-saturated natural water with a pH ranging from 6.5 to 7.7, Gallionella spp. grew uninhibited and biological iron oxidation was an important, and probably the dominant, process. Gallionella growth was not even inhibited in a full-scale filter after plate aeration. From this we conclude that Gallionella spp. can grow under neutral pH and fully aerated conditions when the chemical iron oxidation is retarded by low water temperature and inhibition of the autocatalytic iron oxidation.

  5. RGD-conjugated iron oxide magnetic nanoparticles for magnetic resonance imaging contrast enhancement and hyperthermia.

    PubMed

    Zheng, S W; Huang, M; Hong, R Y; Deng, S M; Cheng, L F; Gao, B; Badami, D

    2014-03-01

    The purpose of this study was to develop a specific targeting magnetic nanoparticle probe for magnetic resonance imaging and therapy in the form of local hyperthermia. Carboxymethyl dextran-coated ultrasmall superparamagnetic iron oxide nanoparticles with carboxyl groups were coupled to cyclic arginine-glycine-aspartic peptides for integrin α(v)β₃ targeting. The particle size, magnetic properties, heating effect, and stability of the arginine-glycine-aspartic-ultrasmall superparamagnetic iron oxide were measured. The arginine-glycine-aspartic-ultrasmall superparamagnetic iron oxide demonstrates excellent stability and fast magneto-temperature response. Magnetic resonance imaging signal intensity of Bcap37 cells incubated with arginine-glycine-aspartic-ultrasmall superparamagnetic iron oxide was significantly decreased compared with that incubated with plain ultrasmall superparamagnetic iron oxide. The preferential uptake of arginine-glycine-aspartic-ultrasmall superparamagnetic iron oxide by target cells was further confirmed by Prussian blue staining and confocal laser scanning microscopy.

  6. Iron oxides stimulate sulfate-driven anaerobic methane oxidation in seeps

    NASA Astrophysics Data System (ADS)

    Sivan, Orit; Antler, Gilad; Turchyn, Alexandra V.; Marlow, Jeffrey J.; Orphan, Victoria J.

    2014-10-01

    Seep sediments are dominated by intensive microbial sulfate reduction coupled to the anaerobic oxidation of methane (AOM). Through geochemical measurements of incubation experiments with methane seep sediments collected from Hydrate Ridge, we provide insight into the role of iron oxides in sulfate-driven AOM. Seep sediments incubated with 13C-labeled methane showed co-occurring sulfate reduction, AOM, and methanogenesis. The isotope fractionation factors for sulfur and oxygen isotopes in sulfate were about 40‰ and 22‰, respectively, reinforcing the difference between microbial sulfate reduction in methane seeps versus other sedimentary environments (for example, sulfur isotope fractionation above 60‰ in sulfate reduction coupled to organic carbon oxidation or in diffusive sedimentary sulfate-methane transition zone). The addition of hematite to these microcosm experiments resulted in significant microbial iron reduction as well as enhancing sulfate-driven AOM. The magnitude of the isotope fractionation of sulfur and oxygen isotopes in sulfate from these incubations was lowered by about 50%, indicating the involvement of iron oxides during sulfate reduction in methane seeps. The similar relative change between the oxygen versus sulfur isotopes of sulfate in all experiments (with and without hematite addition) suggests that oxidized forms of iron, naturally present in the sediment incubations, were involved in sulfate reduction, with hematite addition increasing the sulfate recycling or the activity of sulfur-cycling microorganisms by about 40%. These results highlight a role for natural iron oxides during bacterial sulfate reduction in methane seeps not only as nutrient but also as stimulator of sulfur recycling.

  7. Chitosan-Iron Oxide Coated Graphene Oxide Nanocomposite Hydrogel: A Robust and Soft Antimicrobial Biofilm.

    PubMed

    Konwar, Achyut; Kalita, Sanjeeb; Kotoky, Jibon; Chowdhury, Devasish

    2016-08-17

    We report a robust biofilm with antimicrobial properties fabricated from chitosan-iron oxide coated graphene oxide nanocomposite hydrogel. For the first time, the coprecipitation method was used for the successful synthesis of iron oxide coated graphene oxide (GIO) nanomaterial. After this, films were fabricated by the gel-casting technique aided by the self-healing ability of the chitosan hydrogel network system. Both the nanomaterial and the nanocomposite films were characterized by techniques such as scanning electron microscopy, FT-IR spectroscopy, X-ray diffraction, and vibrating sample magnetometry. Measurements of the thermodynamic stability and mechanical properties of the films indictaed a significant improvement in their thermal and mechanical properties. Moreover, the stress-strain profile indicated the tough nature of the nanocomposite hydrogel films. These improvements, therefore, indicated an effective interaction and good compatibility of the GIO nanomaterial with the chitosan hydrogel matrix. In addition, it was also possible to fabricate films with tunable surface properties such as hydrophobicity simply by varying the loading percentage of GIO nanomaterial in the hydrogel matrix. Fascinatingly, the chitosan-iron oxide coated graphene oxide nanocomposite hydrogel films displayed significant antimicrobial activities against both Gram-positive and Gram-negative bacterial strains, such as methicillin-resistant Staphylococcus aureus, Staphylococcus aureus, and Escherichia coli, and also against the opportunistic dermatophyte Candida albicans. The antimicrobial activities of the films were tested by agar diffusion assay and antimicrobial testing based on direct contact. A comparison of the antimicrobial activity of the chitosan-GIO nanocomposite hydrogel films with those of individual chitosan-graphene oxide and chitosan-iron oxide nanocomposite films demonstrated a higher antimicrobial activity for the former in both types of tests. In vitro hemolysis

  8. Arsenic Bioremediation by Biogenic Iron Oxides and Sulfides

    PubMed Central

    Couture, Raoul-Marie; Van Cappellen, Philippe; Corkhill, Claire L.; Charnock, John M.; Polya, David A.; Vaughan, David; Vanbroekhoven, Karolien; Lloyd, Jonathan R.

    2013-01-01

    Microcosms containing sediment from an aquifer in Cambodia with naturally elevated levels of arsenic in the associated groundwater were used to evaluate the effectiveness of microbially mediated production of iron minerals for in situ As remediation. The microcosms were first incubated without amendments for 28 days, and the release of As and other geogenic chemicals from the sediments into the aqueous phase was monitored. Nitrate or a mixture of sulfate and lactate was then added to stimulate biological Fe(II) oxidation or sulfate reduction, respectively. Without treatment, soluble As concentrations reached 3.9 ± 0.9 μM at the end of the 143-day experiment. However, in the nitrate- and sulfate-plus-lactate-amended microcosms, soluble As levels decreased to 0.01 and 0.41 ± 0.13 μM, respectively, by the end of the experiment. Analyses using a range of biogeochemical and mineralogical tools indicated that sorption onto freshly formed hydrous ferric oxide (HFO) and iron sulfide mineral phases are the likely mechanisms for As removal in the respective treatments. Incorporation of the experimental results into a one-dimensional transport-reaction model suggests that, under conditions representative of the Cambodian aquifer, the in situ precipitation of HFO would be effective in bringing groundwater into compliance with the World Health Organization (WHO) provisional guideline value for As (10 ppb or 0.13 μM), although soluble Mn release accompanying microbial Fe(II) oxidation presents a potential health concern. In contrast, production of biogenic iron sulfide minerals would not remediate the groundwater As concentration below the recommended WHO limit. PMID:23666325

  9. Superparamagnetic iron oxide nanoparticles: magnetic nanoplatforms as drug carriers

    PubMed Central

    Wahajuddin; Arora, Sumit

    2012-01-01

    A targeted drug delivery system is the need of the hour. Guiding magnetic iron oxide nanoparticles with the help of an external magnetic field to its target is the principle behind the development of superparamagnetic iron oxide nanoparticles (SPIONs) as novel drug delivery vehicles. SPIONs are small synthetic γ-Fe2O3 (maghemite) or Fe3O4 (magnetite) particles with a core ranging between 10 nm and 100 nm in diameter. These magnetic particles are coated with certain biocompatible polymers, such as dextran or polyethylene glycol, which provide chemical handles for the conjugation of therapeutic agents and also improve their blood distribution profile. The current research on SPIONs is opening up wide horizons for their use as diagnostic agents in magnetic resonance imaging as well as for drug delivery vehicles. Delivery of anticancer drugs by coupling with functionalized SPIONs to their targeted site is one of the most pursued areas of research in the development of cancer treatment strategies. SPIONs have also demonstrated their efficiency as nonviral gene vectors that facilitate the introduction of plasmids into the nucleus at rates multifold those of routinely available standard technologies. SPION-induced hyperthermia has also been utilized for localized killing of cancerous cells. Despite their potential biomedical application, alteration in gene expression profiles, disturbance in iron homeostasis, oxidative stress, and altered cellular responses are some SPION-related toxicological aspects which require due consideration. This review provides a comprehensive understanding of SPIONs with regard to their method of preparation, their utility as drug delivery vehicles, and some concerns which need to be resolved before they can be moved from bench top to bedside. PMID:22848170

  10. Arsenic bioremediation by biogenic iron oxides and sulfides.

    PubMed

    Omoregie, Enoma O; Couture, Raoul-Marie; Van Cappellen, Philippe; Corkhill, Claire L; Charnock, John M; Polya, David A; Vaughan, David; Vanbroekhoven, Karolien; Lloyd, Jonathan R

    2013-07-01

    Microcosms containing sediment from an aquifer in Cambodia with naturally elevated levels of arsenic in the associated groundwater were used to evaluate the effectiveness of microbially mediated production of iron minerals for in situ As remediation. The microcosms were first incubated without amendments for 28 days, and the release of As and other geogenic chemicals from the sediments into the aqueous phase was monitored. Nitrate or a mixture of sulfate and lactate was then added to stimulate biological Fe(II) oxidation or sulfate reduction, respectively. Without treatment, soluble As concentrations reached 3.9 ± 0.9 μM at the end of the 143-day experiment. However, in the nitrate- and sulfate-plus-lactate-amended microcosms, soluble As levels decreased to 0.01 and 0.41 ± 0.13 μM, respectively, by the end of the experiment. Analyses using a range of biogeochemical and mineralogical tools indicated that sorption onto freshly formed hydrous ferric oxide (HFO) and iron sulfide mineral phases are the likely mechanisms for As removal in the respective treatments. Incorporation of the experimental results into a one-dimensional transport-reaction model suggests that, under conditions representative of the Cambodian aquifer, the in situ precipitation of HFO would be effective in bringing groundwater into compliance with the World Health Organization (WHO) provisional guideline value for As (10 ppb or 0.13 μM), although soluble Mn release accompanying microbial Fe(II) oxidation presents a potential health concern. In contrast, production of biogenic iron sulfide minerals would not remediate the groundwater As concentration below the recommended WHO limit.

  11. Conquering the Dark Side: Colloidal Iron Oxide Nanoparticles

    PubMed Central

    Senpan, Angana; Caruthers, Shelton D.; Rhee, Ilsu; Mauro, Nicholas A.; Pan, Dipanjan; Hu, Grace; Scott, Michael J.; Fuhrhop, Ralph W.; Gaffney, Patrick J.; Wickline, Samuel A.; Lanza, Gregory M.

    2009-01-01

    Nanomedicine approaches to atherosclerotic disease will have significant impact on the practice and outcomes of cardiovascular medicine. Iron oxide nanoparticles have been extensively used for nontargeted and targeted imaging applications based upon highly sensitive T2* imaging properties, which typically result in negative contrast effects that can only be imaged 24 or more hours after systemic administration due to persistent blood pool interference. Although recent advances involving MR pulse sequences have converted these dark contrast voxels into bright ones, the marked delays in imaging from persistent magnetic background interference and prominent dipole blooming effects of the magnetic susceptibility remain barriers to overcome. We report a T1-weighted (T1w) theranostic colloidal iron oxide nanoparticle platform, CION, which is achieved by entrapping oleate-coated magnetite particles within a cross-linked phospholipid nanoemulsion. Contrary to expectations, this formulation decreased T2 effects thus allowing positive T1w contrast detection down to low nanomolar concentrations. CION, a vascular constrained nanoplatform administered in vivo permitted T1w molecular imaging 1 hour after treatment without blood pool interference, although some T2 shortening effects on blood, induced by the superparamagnetic particles persisted. Moreover, CION was shown to encapsulate antiangiogenic drugs, like fumagillin, and retained them under prolonged dissolution, suggesting significant theranostic functionality. Overall, CION is a platform technology, developed with generally recognized as safe components, that overcomes the temporal and spatial imaging challenges associated with current iron oxide nanoparticle T2 imaging agents, and which has theranostic potential in vascular diseases for detecting unstable ruptured plaque or treating atherosclerotic angiogenesis. PMID:19908850

  12. Enriched Iron(III)-Reducing Bacterial Communities are Shaped by Carbon Substrate and Iron Oxide Mineralogy.

    PubMed

    Lentini, Christopher J; Wankel, Scott D; Hansel, Colleen M

    2012-01-01

    Iron (Fe) oxides exist in a spectrum of structures in the environment, with ferrihydrite widely considered the most bioavailable phase. Yet, ferrihydrite is unstable and rapidly transforms to more crystalline Fe(III) oxides (e.g., goethite, hematite), which are poorly reduced by model dissimilatory Fe(III)-reducing microorganisms. This begs the question, what processes and microbial groups are responsible for reduction of crystalline Fe(III) oxides within sedimentary environments? Further, how do changes in Fe mineralogy shape oxide-hosted microbial populations? To address these questions, we conducted a large-scale cultivation effort using various Fe(III) oxides (ferrihydrite, goethite, hematite) and carbon substrates (glucose, lactate, acetate) along a dilution gradient to enrich for microbial populations capable of reducing Fe oxides spanning a wide range of crystallinities and reduction potentials. While carbon source was the most important variable shaping community composition within Fe(III)-reducing enrichments, both Fe oxide type and sediment dilution also had a substantial influence. For instance, with acetate as the carbon source, only ferrihydrite enrichments displayed a significant amount of Fe(III) reduction and the well-known dissimilatory metal reducer Geobacter sp. was the dominant organism enriched. In contrast, when glucose and lactate were provided, all three Fe oxides were reduced and reduction coincided with the presence of fermentative (e.g., Enterobacter spp.) and sulfate-reducing bacteria (e.g., Desulfovibrio spp.). Thus, changes in Fe oxide structure and resource availability may shift Fe(III)-reducing communities between dominantly metal-respiring to fermenting and/or sulfate-reducing organisms which are capable of reducing more recalcitrant Fe phases. These findings highlight the need for further targeted investigations into the composition and activity of speciation-directed metal-reducing populations within natural environments.

  13. Cellular level loading and heating of superparamagnetic iron oxide nanoparticles.

    PubMed

    Kalambur, Venkat S; Longmire, Ellen K; Bischof, John C

    2007-11-20

    Superparamagnetic iron oxide nanoparticles (NPs) hold promise for a variety of biomedical applications due to their properties of visualization using magnetic resonance imaging (MRI), heating with radio frequency (rf), and movement in an external magnetic field. In this study, the cellular loading (uptake) mechanism of dextran- and surfactant-coated iron oxide NPs by malignant prostate tumor cells (LNCaP-Pro5) has been studied, and the feasibility of traditional rf treatment and a new laser heating method was evaluated. The kinetics of cell loading was quantified using magnetophoresis and a colorimetric assay. The results showed that loading of surfactant-coated iron oxide NPs with LNCaP-Pro5 was saturable with time (at 24 h) and extracellular concentration (11 pg Fe/cell at 0.5 mg Fe/mL), indicating that the particles are taken up by an "adsorptive endocytosis" pathway. Dextran-coated NPs, however, were taken up less efficiently (1 pg Fe/cell at 0.5 mg Fe/mL). Loading did not saturate with concentration suggesting uptake by fluid-phase endocytosis. Magnetophoresis suggests that NP-loaded cells can be held using external magnetic fields in microcirculatory flow velocities in vivo or in an appropriately designed extracorporeal circuit. Loaded cells were heated using traditional rf (260A, 357 kHz) and a new laser method (532 nm, 7 ns pulse duration, 0.03 J/pulse, 20 pulse/s). Iron oxide in water was found to absorb sufficiently strongly at 532 nm such that heating of individual NPs and thus loaded cells (1 pg Fe/cell) was effective (<10% cell survival) after 30 s of laser exposure. Radio frequency treatment required higher loading (>10 pg Fe/cell) and longer duration (30 min) when compared to laser to accomplish cell destruction (50% viability at 10 pg Fe/cell). Scaling calculations show that the pulsed laser method can lead to single-cell (loaded with NPs) treatments (200 degrees C temperature change at the surface of an individual NP) unlike traditional rf heating

  14. Iron oxide hydroxide nanoflower assisted removal of arsenic from water

    SciTech Connect

    Raul, Prasanta Kumar; Devi, Rashmi Rekha; Umlong, Iohborlang M.; Thakur, Ashim Jyoti; Banerjee, Saumen; Veer, Vijay

    2014-01-01

    Graphical abstract: Non-magnetic polycrystalline iron oxide hydroxide nanoparticle with flower like morphology is found to play as an effective adsorbent media to remove As(III) from 300 μg L{sup −1} to less than 10 μg L{sup −1} from drinking water over wide range of pH. TEM image clearly reveals that the nanoparticle looks flower like morphology with average particle size less than 20 nm. The maximum sorption capacity of the sorbent is found to be 475 μg g{sup −1} for arsenic at room temperature and the data fitted to different isotherm models indicate the heterogeneity of the adsorbent surface. The material can be regenerated up to 70% using dilute hydrochloric acid and it would be utilized for de-arsenification purposes. - Highlights: • The work includes synthesis of iron oxide hydroxide nanoflower and its applicability for the removal of arsenic from water. • The nanoparticle was characterized using modern instrumental methods like FESEM, TEM, BET, XRD, etc. • The maximum sorption capacity of the sorbent is found to be 475 μg g{sup −1} for arsenic at room temperature. • The sorption is multilayered on the heterogeneous surface of the nano adsorbent. • The mechanism of arsenic removal of IOH nanoflower follows both adsorption and ion-exchange. - Abstract: Non-magnetic polycrystalline iron oxide hydroxide nanoparticle with flower like morphology is found to play as an effective adsorbent media to remove As(III) from 300 μg L{sup −1} to less than 10 μg L{sup −1} from drinking water over wide range of pH. The nanoparticle was characterized by X-ray powder diffraction analysis (XRD), BET surface area, FTIR, FESEM and TEM images. TEM image clearly reveals flower like morphology with average particle size less than 20 nm. The nanoflower morphology is also supported by FESEM images. The maximum sorption capacity of the sorbent is found to be 475 μg g{sup −1} for arsenic and the data fitted to different isotherm models indicate the

  15. Tailoring the magnetic and pharmacokinetic properties of iron oxide magnetic particle imaging tracers

    PubMed Central

    Ferguson, Richard Mathew; Khandhar, Amit P; Arami, Hamed; Hua, Loc; Hovorka, Ondrej; Krishnan, Kannan M.

    2014-01-01

    Magnetic particle imaging (MPI) is an attractive new modality for imaging distributions of iron oxide nanoparticle tracers in vivo. With exceptional contrast, high sensitivity, and good spatial resolution, MPI shows promise for clinical imaging in angiography and oncology. Critically, MPI requires high-quality iron oxide nanoparticle tracers with tailored magnetic and surface properties to achieve its full potential. In this review, we discuss optimizing iron oxide nanoparticles’ physical, magnetic, and pharmacokinetic properties for MPI, highlighting results from our recent work in which we demonstrated tailored, biocompatible iron oxide nanoparticle tracers that provided two times better linear spatial resolution and five times better signal-to-noise ratio than Resovist. PMID:23787461

  16. Catalytic effect of free iron ions and heme-iron on chromophore oxidation of a polyene antibiotic amphotericin B

    NASA Astrophysics Data System (ADS)

    Czernel, Grzegorz; Typek, Rafał; Klimek, Katarzyna; Czuryło, Aleksandra; Dawidowicz, Andrzej L.; Gagoś, Mariusz

    2016-05-01

    Owing to the presence of a chromophore in the amphotericin B (AmB) structure, the molecule can undergo the oxidation process. In this research, AmB chromophore oxidation was catalysed by iron ions (iron(III) chloride (FeCl3), pH 2.5) and by heme-iron (methemoglobin (HbFe(III)), and hemin (heme-Fe(III)) at pH 7.0). Additionally, we compared oxidation processes induced by the aforementioned oxidizing agents with autoxidation by dioxygen (O2) naturally occurring in a sample. The effects of the interaction of the oxidizing agents with AmB were analysed using molecular spectroscopies (electronic absorption (UV-Vis), fluorescence) and LC-MS. The use of a 1,10-phenanthroline (phen) chelator facilitated unambiguous determination of the oxidative effect of free iron(III) ions (FeIII) in an acidic solution on the AmB molecules. Also, the changes in the spectra of fluorescence emission centred at ∼470 nm indicate iron-catalysed processes of AmB chromophore oxidation. Unexpectedly, we found a similar spectroscopic effect for AmB induced by methemoglobin and hemin at pH 7.0. Methemoglobin and hemin at a concentration of 8 × 10-7 M (physiological) significantly increases the rate of the processes of AmB chromophore oxidation relative to the process of autoxidation.

  17. Evidence for equilibrium iron isotope fractionation by nitrate-reducing iron(II)-oxidizing bacteria.

    PubMed

    Kappler, A; Johnson, C M; Crosby, H A; Beard, B L; Newman, D K

    2010-05-10

    Iron isotope fractionations produced during chemical and biological Fe(II) oxidation are sensitive to the proportions and nature of dissolved and solid-phase Fe species present, as well as the extent of isotopic exchange between precipitates and aqueous Fe. Iron isotopes therefore potentially constrain the mechanisms and pathways of Fe redox transformations in modern and ancient environments. In the present study, we followed in batch experiments Fe isotope fractionations between Fe(II)(aq) and Fe(III) oxide/hydroxide precipitates produced by the Fe(III) mineral encrusting, nitrate-reducing, Fe(II)-oxidizing Acidovorax sp. strain BoFeN1. Isotopic fractionation in (56)Fe/(54)Fe approached that expected for equilibrium conditions, assuming an equilibrium Δ(56)Fe(Fe(OH)3 - Fe(II)aq) fractionation factor of +3.0 ‰. Previous studies have shown that Fe(II) oxidation by this Acidovorax strain occurs in the periplasm, and we propose that Fe isotope equilibrium is maintained through redox cycling via coupled electron and atom exchange between Fe(II)(aq) and Fe(III) precipitates in the contained environment of the periplasm. In addition to the apparent equilibrium isotopic fractionation, these experiments also record the kinetic effects of initial rapid oxidation, and possible phase transformations of the Fe(III) precipitates. Attainment of Fe isotope equilibrium between Fe(III) oxide/hydroxide precipitates and Fe(II)(aq) by neutrophilic, Fe(II)-oxidizing bacteria or through abiologic Fe(II)(aq) oxidation is generally not expected or observed, because the poor solubility of their metabolic product, i.e. Fe(III), usually leads to rapid precipitation of Fe(III) minerals, and hence expression of a kinetic fractionation upon precipitation; in the absence of redox cycling between Fe(II)(aq) and precipitate, kinetic isotope fractionations are likely to be retained. These results highlight the distinct Fe isotope fractionations that are produced by different pathways of

  18. Reactions of metal ions at surfaces of hydrous iron oxide

    USGS Publications Warehouse

    Hem, J.D.

    1977-01-01

    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.

  19. Role of humic substances in promoting autotrophic growth in nitrate-dependent iron-oxidizing bacteria.

    PubMed

    Kanaparthi, Dheeraj; Conrad, Ralf

    2015-05-01

    Nitrate-dependent iron oxidation was discovered in 1996 and has been reported from various environments ever since. To date, despite the widespread nature of this process, all attempts to cultivate chemolithoautotrophic nitrate-dependent iron oxidizers have been unsuccessful. The present study was focused on understanding the influence of natural chelating agents of iron, like humic substances, on the culturability, activity, and enumeration, of these microorganisms. Pure culture studies conducted with Thiobacillus denitrificans showed a constant increase in cell mass with a corresponding nitrate-dependent iron oxidation activity only when Fe(II) was provided together with humic substances, compared to no growth in control incubations without humic substances. The presence of a relatively strong chelating agent, such as EDTA, inhibited the growth of Thiobacillus denitrificans. It was concluded that complex formation between humic substances and iron was required for chemolithoautotrophic nitrate-dependent iron oxidation. Most probable number enumerations showed that numbers of chemolithoautotrophic nitrate-dependent iron-oxidizing bacteria were one to three orders of magnitude higher in the presence of humic substances compared to media without. Similar results were obtained when potential nitrate-dependent iron oxidation activity was determined in soil samples. In summary, this study showed that humic substances significantly enhanced the growth and activity of autotrophic nitrate-dependent iron-oxidizing microorganisms, probably by chelation of iron.

  20. Partial oxidation of {alpha}-olefins over iron antimony oxide - influence of carbon number

    SciTech Connect

    Steen, E. van; Schnobel, M.; O`Connor, C.T.

    1996-10-01

    Iron antimony oxide is a well known catalyst for the partial oxidation of propane and 1-butene. Kinetic studies of the partial oxidation of {alpha}-olefins (C{sub 2}-C{sub 9}) revealed that the activity showed a maximum at C{sub 4}. The main products of the partial oxidation of {alpha}-olefins (larger than C{sub 2}) are the conjugated alkenal (acrolein) and dienes. The selectivity to these desired products decreases with increasing chain length probably caused by both the decrease in number of allylic hydrogen atoms and the shielding of them. Ethene could only be oxidized at relatively high temperatures (over 450{degrees}C) and the only observed products were CO and CO{sub 2} indicating the need for the presence of allylic hydrogen for low temperature selective partial oxidation. Increasing the carbon number increases the yield of CO and CO{sub 2} due to shielding of the allylic hydrogen.

  1. Macroscopic and microscopic biodistribution of intravenously administered iron oxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Misra, Adwiteeya; Petryk, Alicia A.; Strawbridge, Rendall R.; Hoopes, P. Jack

    2015-03-01

    Iron oxide nanoparticles (IONP) are being developed for use as a cancer treatment. They have demonstrated efficacy when used either as a monotherapy or in conjunction with conventional chemotherapy and radiation. The success of IONP as a therapeutic tool depends on the delivery of a safe and controlled cytotoxic thermal dose to tumor tissue following activation with an alternating magnetic field (AMF). Prior to clinical approval, knowledge of IONP toxicity, biodistribution and physiological clearance is essential. This preliminary time-course study determines the acute toxicity and biodistribution of 110 nm dextran-coated IONP (iron) in mice, 7 days post systemic, at doses of 0.4, 0.6, and 1.0 mg Fe/ g mouse bodyweight. Acute toxicity, manifested as changes in the behavior of mice, was only observed temporarily at 1.0 mg Fe/ g mouse bodyweight, the highest dose administered. Regardless of dose, mass spectrometry and histological analysis demonstrated over 3 mg Fe/g tissue in organs within the reticuloendotheilial system (i.e. liver, spleen, and lymph nodes). Other organs (brain, heart, lungs, and kidney) had less than 0.5 mg Fe/g tissue with iron predominantly confined to the organ vasculature.

  2. Red Dawn: Characterizing Iron Oxide Minerals in Atmospheric Dust

    NASA Astrophysics Data System (ADS)

    Yauk, K.; Ottenfeld, C. F.; Reynolds, R. L.; Goldstein, H.; Cattle, S.; Berquo, T. S.; Moskowitz, B. M.

    2012-12-01

    Atmospheric dust is comprised of many components including small amounts of iron oxide minerals. Although the iron oxides make up a small weight percent of the bulk dust, they are important because of their roles in ocean fertilization, controls on climate, and as a potential health hazard to humans. Here we report on the iron oxide mineralogy in dust from a large dust storm, dubbed Red Dawn, which engulfed eastern Australia along a 3000 km front on 23 September 2009. Red Dawn originated from the lower Lake Eyre Basin of South Australia, western New South Wales (NSW) and southwestern Queensland and was the worst dust storm to have hit the city of Sydney in more than 60 years. Dust samples were collected from various locations across eastern Australia (Lake Cowal, Orange, Hornsby, Sydney) following the Red Dawn event. Our dust collection provides a good opportunity to study the physical and mineralogical properties of iron oxides from Red Dawn using a combination of reflectance spectroscopy, Mössbauer spectroscopy (MB), and magnetic measurements. Magnetization measurements from 20-400 K reveal that magnetite/maghemite, hematite and goethite are present in all samples with magnetite occurring in trace amounts (< 0.5wt%). However, the amount of magnetite/maghemite even in trace concentrations generally increases from Lake Cowal from west to east (0.01 to 0.29 wt%), with highest magnetite contents in the urban-Sydney sites. These observations indicate the additions of magnetite from local urban sources. Variable temperature Mössbauer spectroscopy (300 K and 4.2 K) indicate that goethite and hematite compose approximately 25-45 % of the Fe-bearing phases in the Orange and Lake Cowal samples. Goethite is more abundant than hematite in the Lake Cowal samples whereas the opposite is observed for Orange. Hematite is observed at both temperatures but goethite only at 4.2 K. The identification of goethite in Mössbauer analyses at low-temperature but not at room temperature

  3. Kinetic Parameters of Binary Iron/Oxidant Pyrolants

    NASA Astrophysics Data System (ADS)

    Shamsipur, Mojtaba; Mahdi Pourmortazavi, Seied; Fathollahi, Manochehr

    2012-04-01

    The thermal properties of pyrotechnic mixtures containing iron powder as fuel and KNO3, KClO3, and KClO4 as oxidants are reported. The thermogravimetry-differential thermal analysis results for pure components and corresponding pyrotechnic mixtures revealed that the melting point, decomposition temperature, and rate of oxygen releasing of the oxidants have dominant effects on ignition reaction of the pyrotechnic mixtures. The apparent activation energy and activation parameters for the combustion processes were evaluated from the differential scanning calorimetry experiments. Based on the ignition temperatures obtained and the resulting kinetic data, the thermal reactivity of the pyrotechnic mixtures was found to decrease as in the order Fe + KClO3 > Fe + KNO3 > Fe + KClO4.

  4. Rapid Spectrophotometric Technique for Quantifying Iron in Cells Labeled with Superparamagnetic Iron Oxide Nanoparticles: Potential Translation to the Clinic

    PubMed Central

    Dadashzadeh, Esmaeel R.; Hobson, Matthew; Bryant, L. Henry; Dean, Dana D.; Frank, Joseph A.

    2012-01-01

    Labeling cells with superparamagnetic iron oxide (SPIO) nanoparticles provides the ability to track cells by Magnetic Resonance Imaging. Quantifying intracellular iron concentration in SPIO labeled cells would allow for the comparison of agents and techniques used to magnetically label cells. Here we describe a rapid spectrophotometric technique (ST) to quantify iron content of SPIO labeled cells, circumventing the previous requirement of an overnight acid digestion. Following lysis with 10% SDS of magnetically labeled cells, quantification of SPIO doped or labeled cells was performed using commonly available spectrophotometric instrument(s) by comparing absorptions at 370 and 750 nm with correction for turbidity of cellular products to determine iron content of each sample. Standard curves demonstrated high linear correlation (R2 = 0.998) between absorbance spectra of iron oxide nanoparticles and concentration in known SPIO doped cells. Comparisons of the ST to ICP-MS or NMR relaxometric (R2) determinations of intracellular iron contents in SPIO containing samples resulted in significant linear correlation between the techniques (R2 vs. ST, R2>0.992, p<0.0001, ST vs. ICP-MS, R2>0.995, p<0.0001) with the limit of detection of ST for iron = 0.66μg/ml. We have developed a rapid straightforward protocol that does not require overnight acid digestion for quantifying iron oxide content in magnetically labeled cells using readily available analytic instrumentation that should greatly expedite advances in comparing SPIO agents and protocols for labeling cells. PMID:23109392

  5. Morphology of biogenic iron oxides records microbial physiology and environmental conditions: toward interpreting iron microfossils.

    PubMed

    Krepski, S T; Emerson, D; Hredzak-Showalter, P L; Luther, G W; Chan, C S

    2013-09-01

    Despite the abundance of Fe and its significance in Earth history, there are no established robust biosignatures for Fe(II)-oxidizing micro-organisms. This limits our ability to piece together the history of Fe biogeochemical cycling and, in particular, to determine whether Fe(II)-oxidizers played a role in depositing ancient iron formations. A promising candidate for Fe(II)-oxidizer biosignatures is the distinctive morphology and texture of extracellular Fe(III)-oxyhydroxide stalks produced by mat-forming microaerophilic Fe(II)-oxidizing micro-organisms. To establish the stalk morphology as a biosignature, morphologic parameters must be quantified and linked to the microaerophilic Fe(II)-oxidizing metabolism and environmental conditions. Toward this end, we studied an extant model organism, the marine stalk-forming Fe(II)-oxidizing bacterium, Mariprofundus ferrooxydans PV-1. We grew cultures in flat glass microslide chambers, with FeS substrate, creating opposing oxygen/Fe(II) concentration gradients. We used solid-state voltammetric microelectrodes to measure chemical gradients in situ while using light microscopy to image microbial growth, motility, and mineral formation. In low-oxygen (2.7-28 μm) zones of redox gradients, the bacteria converge into a narrow (100 μm-1 mm) growth band. As cells oxidize Fe(II), they deposit Fe(III)-oxyhydroxide stalks in this band; the stalks orient directionally, elongating toward higher oxygen concentrations. M. ferrooxydans stalks display a narrow range of widths and uniquely biogenic branching patterns, which result from cell division. Together with filament composition, these features (width, branching, and directional orientation) form a physical record unique to microaerophilic Fe(II)-oxidizer physiology; therefore, stalk morphology is a biosignature, as well as an indicator of local oxygen concentration at the time of formation. Observations of filamentous Fe(III)-oxyhydroxide microfossils from a ~170 Ma marine Fe

  6. Morphology of biogenic iron oxides records microbial physiology and environmental conditions: toward interpreting iron microfossils.

    PubMed

    Krepski, S T; Emerson, D; Hredzak-Showalter, P L; Luther, G W; Chan, C S

    2013-09-01

    Despite the abundance of Fe and its significance in Earth history, there are no established robust biosignatures for Fe(II)-oxidizing micro-organisms. This limits our ability to piece together the history of Fe biogeochemical cycling and, in particular, to determine whether Fe(II)-oxidizers played a role in depositing ancient iron formations. A promising candidate for Fe(II)-oxidizer biosignatures is the distinctive morphology and texture of extracellular Fe(III)-oxyhydroxide stalks produced by mat-forming microaerophilic Fe(II)-oxidizing micro-organisms. To establish the stalk morphology as a biosignature, morphologic parameters must be quantified and linked to the microaerophilic Fe(II)-oxidizing metabolism and environmental conditions. Toward this end, we studied an extant model organism, the marine stalk-forming Fe(II)-oxidizing bacterium, Mariprofundus ferrooxydans PV-1. We grew cultures in flat glass microslide chambers, with FeS substrate, creating opposing oxygen/Fe(II) concentration gradients. We used solid-state voltammetric microelectrodes to measure chemical gradients in situ while using light microscopy to image microbial growth, motility, and mineral formation. In low-oxygen (2.7-28 μm) zones of redox gradients, the bacteria converge into a narrow (100 μm-1 mm) growth band. As cells oxidize Fe(II), they deposit Fe(III)-oxyhydroxide stalks in this band; the stalks orient directionally, elongating toward higher oxygen concentrations. M. ferrooxydans stalks display a narrow range of widths and uniquely biogenic branching patterns, which result from cell division. Together with filament composition, these features (width, branching, and directional orientation) form a physical record unique to microaerophilic Fe(II)-oxidizer physiology; therefore, stalk morphology is a biosignature, as well as an indicator of local oxygen concentration at the time of formation. Observations of filamentous Fe(III)-oxyhydroxide microfossils from a ~170 Ma marine Fe

  7. Enhancing the Performance of the Rechargeable Iron Electrode in Alkaline Batteries with Bismuth Oxide and Iron Sulfide Additives

    SciTech Connect

    Manohar, AK; Yang, CG; Malkhandi, S; Prakash, GKS; Narayanan, SR

    2013-09-07

    Iron-based alkaline rechargeable batteries have the potential of meeting the needs of large-scale electrical energy storage because of their low-cost, robustness and eco-friendliness. However, the widespread commercial deployment of iron-based batteries has been limited by the low charging efficiency and the poor discharge rate capability of the iron electrode. In this study, we have demonstrated iron electrodes containing bismuth oxide and iron sulfide with a charging efficiency of 92% and capable of being discharged at the 3C rate. Such a high value of charging efficiency combined with the ability to discharge at high rates is being reported for the first time. The bismuth oxide additive led to the in situ formation of elemental bismuth and a consequent increase in the overpotential for the hydrogen evolution reaction leading to an increase in the charging efficiency. We observed that the sulfide ions added to the electrolyte and iron sulfide added to the electrode mitigated-electrode passivation and allowed for continuous discharge at high rates. At the 3C discharge rate, a utilization of 0.2 Ah/g was achieved. The performance level of the rechargeable iron electrode demonstrated here is attractive for designing economically-viable large-scale energy storage systems based on alkaline nickel-iron and iron-air batteries. (C) 2013 The Electrochemical Society. All rights reserved.

  8. Iron and manganese oxide mineralization in the Pacific

    USGS Publications Warehouse

    Hein, J.R.; Koschinsky, A.; Halbach, P.; Manheim, F. T.; Bau, M.; Kang, J.-K.; Lubick, N.

    1997-01-01

    Iron, manganese, and iron-manganese deposits occur in nearly all geomorphologic and tectonic environments in the ocean basins and form by one or more of four processes: (1) hydrogenetic precipitation from cold ambient seawater, (2) precipitation from hydrothermal fluids, (3) precipitation from sediment pore waters that have been modified from bottom water compositions by diagenetic reactions in the sediment column and (4) replacement of rocks and sediment. Iron and manganese deposits occur in five forms: nodules, crusts, cements, mounds and sediment-hosted stratabound layers. Seafloor oxides show a wide range of compositions from nearly pure iron to nearly pure manganese end members. Fe/Mn ratios vary from about 24 000 (up to 58% elemental Fe) for hydrothermal seamount ironstones to about 0.001 (up to 52% Mn) for hydrothermal stratabound manganese oxides from active volcanic arcs. Hydrogenetic Fe-Mn crusts that occur on most seamounts in the ocean basins have a mean Fe/Mn ratio of 0.7 for open-ocean seamount crusts and 1.2 for continental margin seamount crusts. Fe-Mn nodules of potential economic interest from the Clarion-Clipperton Zone have a mean Fe/Mn ratio of 0.3, whereas the mean ratio for nodules from elsewhere in the Pacific is about 0.7. Crusts are enriched in Co, Ni and Pt and nodules in Cu and Ni, and both have significant concentrations of Pb, Zn, Ba, Mo, V and other elements. In contrast, hydrothermal deposits commonly contain only minor trace metal contents, although there are many exceptions, for example, with Ni contents up to 0.66%, Cr to 1.2%, and Zn to 1.4%. Chondrite-normalized REE patterns generally show a positive Ce anomaly and abundant ??REEs for hydrogenetic and mixed hydrogenetic-diagenetic deposits, whereas the Ce anomaly is negative for hydrothermal deposits and ??REE contents are low. However, the Ce anomaly in crusts may vary from strongly positive in East Pacific crusts to slightly negative in West Pacific crusts, which may reflect

  9. Microemulsion Synthesis of Iron Core/Iron Oxide Shell Magnetic Nanoparticles and Their Physicochemical Properties

    PubMed Central

    Kekalo, Katsiaryna; Koo, Katherine; Zeitchick, Evan; Baker, Ian

    2015-01-01

    Iron magnetic nanoparticles were synthesized under an inert atmosphere via the reaction between FeCl3 and NaBH4 in droplets of water in a microemulsion consisting of octane with cetyl trimethylammonium bromide and butanol as surfactants. A thin Fe3O4 layer was produced on the iron nanoparticles using slow, controlled oxidation at room temperature. A silica shell was deposited on the Fe3O4 using 3-aminopropyltrimethoxysilane following the method of Zhang et al. [Mater. Sci. Eng. C 30 (2010) 92–97]. The structure and chemistry of the resulting nanoparticles were studied using variety of methods and their magnetic properties were determined. The diameter of the iron core was typically 8–16 nm, while the thickness of the Fe3O4 shell was 2–3 nm. The presence of the silica layer was confirmed using Fourier transform infra-red spectroscopy and the number of NH2-groups on each nanoparticle was determined based on colorimetric tests using ortho-phthalaldehyde. PMID:26549922

  10. Formation of the first oxidized iron in the solar system

    NASA Astrophysics Data System (ADS)

    Grossman, Lawrence; Fedkin, Alexei V.; Simon, Steven B.

    2012-12-01

    Abstract-For fayalite formation times of several thousand years, and systems enriched in water by a factor of ten relative to solar composition, 1 μm radius olivine grains could reach 2 mole% fayalite and 0.1 μm grains 5 mole% by nebular condensation, well short of the values appropriate for precursors of most chondrules and the values found in the matrices of unequilibrated ordinary chondrites. Even 10 μm olivine crystals could reach 30 mole% fayalite above 1100 K in solar gas if condensation of metallic nickel-<span class="hlt">iron</span> were delayed sufficiently by supersaturation. Consideration of the surface tensions of several phases with equilibrium condensation temperatures above that of metallic <span class="hlt">iron</span> shows that, even if they were supersaturated, they would still nucleate homogeneously above the equilibrium condensation temperature of metallic <span class="hlt">iron</span>. This phenomenon would have provided nuclei for heterogeneous nucleation of metallic nickel-<span class="hlt">iron</span>, thus preventing the latter from supersaturating significantly and preventing olivine from becoming fayalitic. Unless a way is found to make nebular regions far more <span class="hlt">oxidizing</span> than in existing models, it is unlikely that chondrule precursors or the matrix olivine grains of unequilibrated ordinary chondrites obtained their fayalite contents by condensation processes. Perhaps stabilization of FeO occurred after condensation of water ice and accretion of icy planetesimals, during heating of the planetesimals and/or in hot, dense, water-rich vapor plumes generated by impacts on them. This would imply that FeO is a relatively young feature of nebular materials.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4007256','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4007256"><span id="translatedtitle">Evaluation of Nanodispersion of <span class="hlt">Iron</span> <span class="hlt">Oxides</span> Using Various Polymers</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Tanaka, Y.; Ueyama, H.; Ogata, M.; Daikoku, T.; Morimoto, M.; Kitagawa, A.; Imajo, Y.; Tahara, T.; Inkyo, M.; Yamaguchi, N.; Nagata, S.</p> <p>2014-01-01</p> <p>In order to create Fe2O3 and Fe2O3·H2O nanoparticles, various polymers were used as dispersing agents, and the resulting effects on the dispersibility and nanoparticulation of the <span class="hlt">iron</span> <span class="hlt">oxides</span> were evaluated. It was revealed that not only the solution viscosity but also the molecular length of the polymers and the surface tension of the particles affected the dispersibility of Fe2O3 and Fe2O3·H2O particles. Using the dispersing agents 7.5% hydroxypropylcellulose-SSL, 6.0% Pharmacoat 603, 5.0% and 6.5% Pharmacoat 904 and 7.0% Metolose SM-4, Fe2O3 nanoparticles were successfully fabricated by wet milling using Ultra Apex Mill. Fe2O3·H2O nanoparticles could also be produced using 5.0% hydroxypropylcellulose-SSL and 4.0 and 7.0% Pharmacoat 904. The index for dispersibility developed in this study appears to be an effective indicator of success in fabricating nanoparticles of <span class="hlt">iron</span> <span class="hlt">oxides</span> by wet milling using Ultra Apex Mill. PMID:24799739</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27448065','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27448065"><span id="translatedtitle">Tuning the structure and habit of <span class="hlt">iron</span> <span class="hlt">oxide</span> mesocrystals.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wetterskog, Erik; Klapper, Alice; Disch, Sabrina; Josten, Elisabeth; Hermann, Raphaël P; Rücker, Ulrich; Brückel, Thomas; Bergström, Lennart; Salazar-Alvarez, German</p> <p>2016-08-25</p> <p>A precise control over the meso- and microstructure of ordered and aligned nanoparticle assemblies, i.e., mesocrystals, is essential in the quest for exploiting the collective material properties for potential applications. In this work, we produced evaporation-induced self-assembled mesocrystals with different mesostructures and crystal habits based on <span class="hlt">iron</span> <span class="hlt">oxide</span> nanocubes by varying the nanocube size and shape and by applying magnetic fields. A full 3D characterization of the mesocrystals was performed using image analysis, high-resolution scanning electron microscopy and Grazing Incidence Small Angle X-ray Scattering (GISAXS). This enabled the structural determination of e.g. multi-domain mesocrystals with complex crystal habits and the quantification of interparticle distances with sub-nm precision. Mesocrystals of small nanocubes (l = 8.6-12.6 nm) are isostructural with a body centred tetragonal (bct) lattice whereas assemblies of the largest nanocubes in this study (l = 13.6 nm) additionally form a simple cubic (sc) lattice. The mesocrystal habit can be tuned from a square, hexagonal to star-like and pillar shapes depending on the particle size and shape and the strength of the applied magnetic field. Finally, we outline a qualitative phase diagram of the evaporation-induced self-assembled superparamagnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> nanocube mesocrystals based on nanocube edge length and magnetic field strength. PMID:27448065</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/pages/biblio/1319205-tuning-structure-habit-iron-oxide-mesocrystals','SCIGOV-DOEP'); return false;" href="http://www.osti.gov/pages/biblio/1319205-tuning-structure-habit-iron-oxide-mesocrystals"><span id="translatedtitle">Tuning the structure and habit of <span class="hlt">iron</span> <span class="hlt">oxide</span> mesocrystals</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGESBeta</a></p> <p>Wetterskog, Erik; Klapper, Alice; Disch, Sabrina; Josten, Elisabeth; Hermann, Raphaël P.; Rücker, Ulrich; Brückel, Thomas; Bergström, Lennart; Salazar-Alvarez, German</p> <p>2016-07-11</p> <p>A precise control over the meso- and microstructure of ordered and aligned nanoparticle assemblies, i.e., mesocrystals, is essential in the quest for exploiting the collective material properties for potential applications. In this work, we produced evaporation-induced self-assembled mesocrystals with different mesostructures and crystal habits based on <span class="hlt">iron</span> <span class="hlt">oxide</span> nanocubes by varying the nanocube size and shape and by applying magnetic fields. A full 3D characterization of the mesocrystals was performed using image analysis, high-resolution scanning electron microscopy and Grazing Incidence Small Angle X-ray Scattering (GISAXS). This enabled the structural determination of e.g. multi-domain mesocrystals with complex crystal habits and themore » quantification of interparticle distances with sub-nm precision. Mesocrystals of small nanocubes (l = 8.6 12.6 nm) are isostructural with a body centred tetragonal (bct ) lattice whereas assemblies of the largest nanocubes in this study (l = 13.6 nm) additionally form a simple cubic (sc) lattice. The mesocrystal habit can be tuned from a square, hexagonal to star-like and pillar shapes depending on the particle size and shape and the strength of the applied magnetic field. Finally, we outline a qualitative phase diagram of the evaporation-induced self-assembled superparamagnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> nanocube mesocrystals based on nanocube edge length and magnetic field strength.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27261762','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27261762"><span id="translatedtitle">Thermal and magnetic properties of chitosan-<span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Soares, Paula I P; Machado, Diana; Laia, César; Pereira, Laura C J; Coutinho, Joana T; Ferreira, Isabel M M; Novo, Carlos M M; Borges, João Paulo</p> <p>2016-09-20</p> <p>Chitosan is a biopolymer widely used for biomedical applications such as drug delivery systems, wound healing, and tissue engineering. Chitosan can be used as coating for other types of materials such as <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles, improving its biocompatibility while extending its range of applications. In this work <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles (Fe3O4 NPs) produced by chemical precipitation and thermal decomposition and coated with chitosan with different molecular weights were studied. Basic characterization on bare and chitosan-Fe3O4 NPs was performed demonstrating that chitosan does not affect the crystallinity, chemical composition, and superparamagnetic properties of the Fe3O4 NPs, and also the incorporation of Fe3O4 NPs into chitosan nanoparticles increases the later hydrodynamic diameter without compromising its physical and chemical properties. The nano-composite was tested for magnetic hyperthermia by applying an alternating current magnetic field to the samples demonstrating that the heating ability of the Fe3O4 NPs was not significantly affected by chitosan.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1319205','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1319205"><span id="translatedtitle">Tuning the structure and habit of <span class="hlt">iron</span> <span class="hlt">oxide</span> mesocrystals</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Wetterskog, Erik; Klapper, Alice; Disch, Sabrina; Josten, Elisabeth; Hermann, Raphael P; Ruecker, Ulrich; Brueckel, Th.; Bergstrom, Lennart; Salazar-Alvarez, G.</p> <p>2016-01-01</p> <p>A precise control over the meso- and microstructure of ordered and aligned nanoparticle assemblies, i.e., mesocrystals, is essential in the quest for exploiting the collective material properties for potential applications. In this work, we produced evaporation-induced self-assembled mesocrystals with different mesostructures and crystal habits based on <span class="hlt">iron</span> <span class="hlt">oxide</span> nanocubes by varying the nanocube size and shape and by applying magnetic fields. A full 3D characterization of the mesocrystals was performed using image analysis, high-resolution scanning electron microscopy and Grazing Incidence Small Angle X-ray Scattering (GISAXS). This enabled the structural determination of e.g. multi-domain mesocrystals with complex crystal habits and the quantification of interparticle distances with sub-nm precision. Mesocrystals of small nanocubes (l = 8.6 12.6 nm) are isostructural with a body centred tetragonal (bct ) lattice whereas assemblies of the largest nanocubes in this study (l = 13.6 nm) additionally form a simple cubic (sc) lattice. The mesocrystal habit can be tuned from a square, hexagonal to star-like and pillar shapes depending on the particle size and shape and the strength of the applied magnetic field. Finally, we outline a qualitative phase diagram of the evaporation-induced self-assembled superparamagnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> nanocube mesocrystals based on nanocube edge length and magnetic field strength.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27248668','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27248668"><span id="translatedtitle">Magnetic <span class="hlt">Iron</span> <span class="hlt">Oxide</span> Nanoparticle Seeded Growth of Nucleotide Coordinated Polymers.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Liang, Hao; Liu, Biwu; Yuan, Qipeng; Liu, Juewen</p> <p>2016-06-22</p> <p>The introduction of functional molecules to the surface of magnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles (NPs) is of critical importance. Most previously reported methods were focused on surface ligand attachment either by physisorption or covalent conjugation, resulting in limited ligand loading capacity. In this work, we report the seeded growth of a nucleotide coordinated polymer shell, which can be considered as a special form of adsorption by forming a complete shell. Among all of the tested metal ions, Fe(3+) is the most efficient for this seeded growth. A diverse range of guest molecules, including small organic dyes, proteins, DNA, and gold NPs, can be encapsulated in the shell. All of these molecules were loaded at a much higher capacity compared to that on the naked <span class="hlt">iron</span> <span class="hlt">oxide</span> NP core, confirming the advantage of the coordination polymer (CP) shell. In addition, the CP shell provides better guest protein stability compared to that of simple physisorption while retaining guest activity as confirmed by the entrapped glucose oxidase assay. Use of this system as a peroxidase nanozyme and glucose biosensor was demonstrated, detecting glucose as low as 1.4 μM with excellent stability. This work describes a new way to functionalize inorganic materials with a biocompatible shell. PMID:27248668</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26011415','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26011415"><span id="translatedtitle">Dechlorination of polychlorinated biphenyls by <span class="hlt">iron</span> and its <span class="hlt">oxides</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sun, Yifei; Liu, Xiaoyuan; Kainuma, Masashi; Wang, Wei; Takaoka, Masaki; Takeda, Nobuo</p> <p>2015-10-01</p> <p>The decomposition efficiency of polychlorinated biphenyls (PCBs) was determined using elemental <span class="hlt">iron</span> (Fe) and three <span class="hlt">iron</span> (hydr)<span class="hlt">oxides</span>, i.e., α-Fe2O3, Fe3O4, and α-FeOOH, as catalysts. The experiments were performed using four distinct PCB congeners (PCB-209, PCB-153, and the coplanar PCB-167 and PCB-77) at temperatures ranging from 180 °C to 380 °C and under an inert, <span class="hlt">oxidizing</span> or reducing atmosphere composed of N2, N2+O2, or N2+H2. From these three options N2 showed to provide the best reaction atmosphere. Among the <span class="hlt">iron</span> compounds tested, Fe3O4 showed the highest activity for decomposing PCBs. The decomposition efficiencies of PCB-209, PCB-167, PCB-153, and PCB-77 by Fe3O4 in an N2 atmosphere at 230 °C were 88.5%, 82.5%, 69.9%, and 66.4%, respectively. Other inorganic chlorine (Cl) products which were measured by the amount of inorganic Cl ions represented 82.5% and 76.1% of the reaction products, showing that ring cleavage of PCBs was the main elimination process. Moreover, the dechlorination did not require a particular hydrogen donor. We used X-ray photoelectron spectroscopy to analyze the elemental distribution at the catalyst's surface. The O/Fe ratio influenced upon the decomposition efficiency of PCBs: the lower this ratio, the higher the decomposition efficiency. X-ray absorption near edge structure spectra showed that α-Fe2O3 effectively worked as a catalyst, while Fe3O4 and α-FeOOH were consumed as reactants, as their final state is different from their initial state. Finally, a decomposition pathway was postulated in which the Cl atoms in ortho-positions were more difficult to eliminate than those in the para- or meta-positions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015SPIE.9326E..0PM','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015SPIE.9326E..0PM"><span id="translatedtitle">Effect of radiation energy and intracellular <span class="hlt">iron</span> dose on <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticle enhancement of radiation cytotoxicity</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mazur, Courtney M.; Strawbridge, Rendall R.; Thompson, Ella S.; Petryk, Alicia A.; Gladstone, David J.; Hoopes, P. Jack</p> <p>2015-03-01</p> <p><span class="hlt">Iron</span> <span class="hlt">oxide</span> nanoparticles (IONPs) are one of several high-Z materials currently being investigated for their ability to enhance the cytotoxic effects of therapeutic ionizing radiation. Studies with <span class="hlt">iron</span> <span class="hlt">oxide</span>, silver, gold, and hafnium <span class="hlt">oxide</span> suggest radiation dose, radiation energy, cell type, and the type and level of metallic nanoparticle are all critical factors in achieving radiation enhancement in tumor cells. Using a single 4 Gy radiation dose, we compared the level of tumor cell cytotoxicity at two different intracellular <span class="hlt">iron</span> concentrations and two different radiation energies in vitro. IONPs were added to cell culture media at concentrations of 0.25 mg Fe/mL and 1.0 mg Fe/mL and incubated with murine breast adenocarcinoma (MTG-B) cells for 72 hours. Extracellular <span class="hlt">iron</span> was then removed and cells were irradiated at either 662 keV or 10 MV. At the 0.25 mg Fe/mL dose (4 pg Fe/cell), radiation energy did not affect the level of cytotoxicity. However with 1.0 mg Fe/mL (9 pg Fe/cell), the higher 10 MV radiation energy resulted in 50% greater cytotoxicity as compared to cells without IONPs irradiated at this energy. These results suggest IONPs may be able to significantly enhance the cytotoxic effects of radiation and improve therapeutic ratio if they can be selectively associated with cancer cells and/or tumors. Ongoing in vivo studies of IONP radiation enhancement in a murine tumor model are too immature to draw conclusions from at this time, however preliminary data suggests similar effectiveness of IONP radiation enhancement at 6 MV and 18 MV energy levels. In addition to the IONP-based radiation enhancement demonstrated here, the use of tumor-localized IONP with an externally delivered, non-toxic alternating magnetic field affords the opportunity to selectively heat and kill tumor cells. Combining IONP-based radiation sensitization and heat-based cytotoxicity provides a unique and potentially highly effective opportunity for therapeutic ratio enhancement.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27605075','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27605075"><span id="translatedtitle">Discovery of Fe7O9: a new <span class="hlt">iron</span> <span class="hlt">oxide</span> with a complex monoclinic structure.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sinmyo, Ryosuke; Bykova, Elena; Ovsyannikov, Sergey V; McCammon, Catherine; Kupenko, Ilya; Ismailova, Leyla; Dubrovinsky, Leonid</p> <p>2016-01-01</p> <p><span class="hlt">Iron</span> <span class="hlt">oxides</span> are fundamentally important compounds for basic and applied sciences as well as in numerous industrial applications. In this work we report the synthesis and investigation of a new binary <span class="hlt">iron</span> <span class="hlt">oxide</span> with the hitherto unknown stoichiometry of Fe7O9. This new <span class="hlt">oxide</span> was synthesized at high-pressure high-temperature (HP-HT) conditions, and its black single crystals were successfully recovered at ambient conditions. By means of single crystal X-ray diffraction we determined that Fe7O9 adopts a monoclinic C2/m lattice with the most distorted crystal structure among the binary <span class="hlt">iron</span> <span class="hlt">oxides</span> known to date. The synthesis of Fe7O9 opens a new portal to exotic <span class="hlt">iron</span>-rich (M,Fe)7O9 <span class="hlt">oxides</span> with unusual stoichiometry and distorted crystal structures. Moreover, the crystal structure and phase relations of such new <span class="hlt">iron</span> <span class="hlt">oxide</span> groups may provide new insight into the cycling of volatiles in the Earth's interior.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20446731','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20446731"><span id="translatedtitle">Photoreductive dissolution of <span class="hlt">iron</span> <span class="hlt">oxides</span> trapped in ice and its environmental implications.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kim, Kitae; Choi, Wonyong; Hoffmann, Michael R; Yoon, Ho-Il; Park, Byong-Kwon</p> <p>2010-06-01</p> <p>The availability of <span class="hlt">iron</span> has been thought to be a main limiting factor for the productivity of phytoplankton and related with the uptake of atmospheric CO(2) and algal blooms in fresh and sea waters. In this work, the formation of bioavailable <span class="hlt">iron</span> (Fe(II)(aq)) from the dissolution of <span class="hlt">iron</span> <span class="hlt">oxide</span> particles was investigated in the ice phase under both UV and visible light irradiation. The photoreductive dissolution of <span class="hlt">iron</span> <span class="hlt">oxides</span> proceeded slowly in aqueous solution (pH 3.5) but was significantly accelerated in polycrystalline ice, subsequently releasing more bioavailable ferrous <span class="hlt">iron</span> upon thawing. The enhanced photogeneration of Fe(II)(aq) in ice was confirmed regardless of the type of <span class="hlt">iron</span> <span class="hlt">oxides</span> [hematite, maghemite (gamma-Fe(2)O(3)), goethite (alpha-FeOOH)] and the kind of electron donors. The ice-enhanced dissolution of <span class="hlt">iron</span> <span class="hlt">oxides</span> was also observed under visible light irradiation, although the dissolution rate was much slower compared with the case of UV radiation. The <span class="hlt">iron</span> <span class="hlt">oxide</span> particles and organic electron donors (if any) in ice are concentrated and aggregated in the liquid-like grain boundary region (freeze concentration effect) where protons are also highly concentrated (lower pH). The enhanced photodissolution of <span class="hlt">iron</span> <span class="hlt">oxides</span> should occur in this confined boundary region. We hypothesized that electron hopping through the interconnected grain boundaries of <span class="hlt">iron</span> <span class="hlt">oxide</span> particles facilitates the separation of photoinduced charge pairs. The outdoor experiments carried out under ambient solar radiation of Ny-Alesund (Svalbard, 78 degrees 55'N) also showed that the generation of dissolved Fe(II)(aq) via photoreductive dissolution is enhanced when <span class="hlt">iron</span> <span class="hlt">oxides</span> are trapped in ice. Our results imply that the ice(snow)-covered surfaces and ice-cloud particles containing <span class="hlt">iron</span>-rich mineral dusts in the polar and cold environments provide a source of bioavailable <span class="hlt">iron</span> when they thaw.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_13 --> <div id="page_14" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="261"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/866527','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/866527"><span id="translatedtitle">Nickel aluminides and nickel-<span class="hlt">iron</span> aluminides for use in <span class="hlt">oxidizing</span> environments</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Liu, Chain T.</p> <p>1988-03-15</p> <p>Nickel aluminides and nickel-<span class="hlt">iron</span> aluminides treated with hafnium or zirconium, boron and cerium to which have been added chromium to significantly improve high temperature ductility, creep resistance and <span class="hlt">oxidation</span> properties in <span class="hlt">oxidizing</span> environments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21504536','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21504536"><span id="translatedtitle"><span class="hlt">Iron</span> isotope fractionation during microbial dissimilatory <span class="hlt">iron</span> <span class="hlt">oxide</span> reduction in simulated Archaean seawater.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Percak-Dennett, E M; Beard, B L; Xu, H; Konishi, H; Johnson, C M; Roden, E E</p> <p>2011-05-01</p> <p>The largest Fe isotope excursion yet measured in marine sedimentary rocks occurs in shales, carbonates, and banded <span class="hlt">iron</span> formations of Neoarchaean and Paleoproterozoic age. The results of field and laboratory studies suggest a potential role for microbial dissimilatory <span class="hlt">iron</span> reduction (DIR) in producing this excursion. However, most experimental studies of Fe isotope fractionation during DIR have been conducted in simple geochemical systems, using pure Fe(III) <span class="hlt">oxide</span> substrates that are not direct analogues to phases likely to have been present in Precambrian marine environments. In this study, Fe isotope fractionation was investigated during microbial reduction of an amorphous Fe(III) <span class="hlt">oxide</span>-silica coprecipitate in anoxic, high-silica, low-sulphate artificial Archaean seawater at 30 °C to determine if such conditions alter the extent of reduction or isotopic fractionations relative to those observed in simple systems. The Fe(III)-Si coprecipitate was highly reducible (c. 80% reduction) in the presence of excess acetate. The coprecipitate did not undergo phase conversion (e.g. to green rust, magnetite or siderite) during reduction. <span class="hlt">Iron</span> isotope fractionations suggest that rapid and near-complete isotope exchange took place among all Fe(II) and Fe(III) components, in contrast to previous work on goethite and hematite, where exchange was limited to the outer few atom layers of the substrate. Large quantities of low-δ(56)Fe Fe(II) (aqueous and solid phase) were produced during reduction of the Fe(III)-Si coprecipitate. These findings shed new light on DIR as a mechanism for producing Fe isotope variations observed in Neoarchaean and Paleoproterozoic marine sedimentary rocks.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/21504536','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/21504536"><span id="translatedtitle"><span class="hlt">Iron</span> isotope fractionation during microbial dissimilatory <span class="hlt">iron</span> <span class="hlt">oxide</span> reduction in simulated Archaean seawater.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Percak-Dennett, E M; Beard, B L; Xu, H; Konishi, H; Johnson, C M; Roden, E E</p> <p>2011-05-01</p> <p>The largest Fe isotope excursion yet measured in marine sedimentary rocks occurs in shales, carbonates, and banded <span class="hlt">iron</span> formations of Neoarchaean and Paleoproterozoic age. The results of field and laboratory studies suggest a potential role for microbial dissimilatory <span class="hlt">iron</span> reduction (DIR) in producing this excursion. However, most experimental studies of Fe isotope fractionation during DIR have been conducted in simple geochemical systems, using pure Fe(III) <span class="hlt">oxide</span> substrates that are not direct analogues to phases likely to have been present in Precambrian marine environments. In this study, Fe isotope fractionation was investigated during microbial reduction of an amorphous Fe(III) <span class="hlt">oxide</span>-silica coprecipitate in anoxic, high-silica, low-sulphate artificial Archaean seawater at 30 °C to determine if such conditions alter the extent of reduction or isotopic fractionations relative to those observed in simple systems. The Fe(III)-Si coprecipitate was highly reducible (c. 80% reduction) in the presence of excess acetate. The coprecipitate did not undergo phase conversion (e.g. to green rust, magnetite or siderite) during reduction. <span class="hlt">Iron</span> isotope fractionations suggest that rapid and near-complete isotope exchange took place among all Fe(II) and Fe(III) components, in contrast to previous work on goethite and hematite, where exchange was limited to the outer few atom layers of the substrate. Large quantities of low-δ(56)Fe Fe(II) (aqueous and solid phase) were produced during reduction of the Fe(III)-Si coprecipitate. These findings shed new light on DIR as a mechanism for producing Fe isotope variations observed in Neoarchaean and Paleoproterozoic marine sedimentary rocks. PMID:21504536</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25915449','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25915449"><span id="translatedtitle">Potential for microbial <span class="hlt">oxidation</span> of ferrous <span class="hlt">iron</span> in basaltic glass.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Xiong, Mai Yia; Shelobolina, Evgenya S; Roden, Eric E</p> <p>2015-05-01</p> <p>Basaltic glass (BG) is an amorphous ferrous <span class="hlt">iron</span> [Fe(II)]-containing material present in basaltic rocks, which are abundant on rocky planets such as Earth and Mars. Previous research has suggested that Fe(II) in BG can serve as an energy source for chemolithotrophic microbial metabolism, which has important ramifications for potential past and present microbial life on Mars. However, to date there has been no direct demonstration of microbially catalyzed <span class="hlt">oxidation</span> of Fe(II) in BG. In this study, three different culture systems were used to investigate the potential for microbial <span class="hlt">oxidation</span> of Fe(II) in BG, including (1) the chemolithoautotrophic Fe(II)-<span class="hlt">oxidizing</span>, nitrate-reducing "Straub culture"; (2) the mixotrophic Fe(II)-<span class="hlt">oxidizing</span>, nitrate-reducing organism Desulfitobacterium frappieri strain G2; and (3) indigenous microorganisms from a streambed Fe seep in Wisconsin. The BG employed consisted of clay and silt-sized particles of freshly quenched lava from the TEB flow in Kilauea, Hawaii. Soluble Fe(II) or chemically reduced NAu-2 smectite (RS) were employed as positive controls to verify Fe(II) <span class="hlt">oxidation</span> activity in the culture systems. All three systems demonstrated <span class="hlt">oxidation</span> of soluble Fe(II) and/or structural Fe(II) in RS, whereas no <span class="hlt">oxidation</span> of Fe(II) in BG material was observed. The inability of the Straub culture to <span class="hlt">oxidize</span> Fe(II) in BG was particularly surprising, as this culture can <span class="hlt">oxidize</span> other insoluble Fe(II)-bearing minerals such as biotite, magnetite, and siderite. Although the reason for the resistance of the BG toward enzymatic <span class="hlt">oxidation</span> remains unknown, it seems possible that the absence of distinct crystal faces or edge sites in the amorphous glass renders the material resistant to such attack. These findings have implications with regard to the idea that Fe(II)-Si-rich phases in basalt rocks could provide a basis for chemolithotrophic microbial life on Mars, specifically in neutral-pH environments where acid-promoted mineral dissolution and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25915449','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25915449"><span id="translatedtitle">Potential for microbial <span class="hlt">oxidation</span> of ferrous <span class="hlt">iron</span> in basaltic glass.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Xiong, Mai Yia; Shelobolina, Evgenya S; Roden, Eric E</p> <p>2015-05-01</p> <p>Basaltic glass (BG) is an amorphous ferrous <span class="hlt">iron</span> [Fe(II)]-containing material present in basaltic rocks, which are abundant on rocky planets such as Earth and Mars. Previous research has suggested that Fe(II) in BG can serve as an energy source for chemolithotrophic microbial metabolism, which has important ramifications for potential past and present microbial life on Mars. However, to date there has been no direct demonstration of microbially catalyzed <span class="hlt">oxidation</span> of Fe(II) in BG. In this study, three different culture systems were used to investigate the potential for microbial <span class="hlt">oxidation</span> of Fe(II) in BG, including (1) the chemolithoautotrophic Fe(II)-<span class="hlt">oxidizing</span>, nitrate-reducing "Straub culture"; (2) the mixotrophic Fe(II)-<span class="hlt">oxidizing</span>, nitrate-reducing organism Desulfitobacterium frappieri strain G2; and (3) indigenous microorganisms from a streambed Fe seep in Wisconsin. The BG employed consisted of clay and silt-sized particles of freshly quenched lava from the TEB flow in Kilauea, Hawaii. Soluble Fe(II) or chemically reduced NAu-2 smectite (RS) were employed as positive controls to verify Fe(II) <span class="hlt">oxidation</span> activity in the culture systems. All three systems demonstrated <span class="hlt">oxidation</span> of soluble Fe(II) and/or structural Fe(II) in RS, whereas no <span class="hlt">oxidation</span> of Fe(II) in BG material was observed. The inability of the Straub culture to <span class="hlt">oxidize</span> Fe(II) in BG was particularly surprising, as this culture can <span class="hlt">oxidize</span> other insoluble Fe(II)-bearing minerals such as biotite, magnetite, and siderite. Although the reason for the resistance of the BG toward enzymatic <span class="hlt">oxidation</span> remains unknown, it seems possible that the absence of distinct crystal faces or edge sites in the amorphous glass renders the material resistant to such attack. These findings have implications with regard to the idea that Fe(II)-Si-rich phases in basalt rocks could provide a basis for chemolithotrophic microbial life on Mars, specifically in neutral-pH environments where acid-promoted mineral dissolution and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19167810','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19167810"><span id="translatedtitle">Fenton-like <span class="hlt">oxidation</span> of Rhodamine B in the presence of two types of <span class="hlt">iron</span> (II, III) <span class="hlt">oxide</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Xue, Xiaofei; Hanna, Khalil; Deng, Nansheng</p> <p>2009-07-15</p> <p>The catalytic efficiency of <span class="hlt">iron</span> (II, III) <span class="hlt">oxide</span> to promote Fenton-like reaction was examined by employing Rhodamine B (RhB) as a model compound at neutral pH. Two types of <span class="hlt">iron</span> (II, III) <span class="hlt">oxides</span> were used as heterogeneous catalysts and characterized by XRD, Mössbauer spectroscopy, BET surface area, particle size and chemical analyses. The adsorption to the catalyst changed significantly with the pH value and the sorption isotherm was fitted using the Langmuir model for both solids. Both sorption and FTIR results indicated that surface complexation reaction may take place in the system. The variation of <span class="hlt">oxidation</span> efficiency against H(2)O(2) dosage and amount of exposed surface area per unit volume was evaluated and correlated with the adsorption behavior in the absence of <span class="hlt">oxidant</span>. The occurrence of optimum amount of H(2)O(2) or of exposed surface area for the effective degradation of RhB could be explained by the scavenging effect of hydroxyl radical by H(2)O(2) or by <span class="hlt">iron</span> <span class="hlt">oxide</span> surface. Sorption and decolourization rate of RhB as well as H(2)O(2) decomposition rate were found to be dependent on the surface characteristics of <span class="hlt">iron</span> <span class="hlt">oxide</span>. The kinetic <span class="hlt">oxidation</span> experiments showed that structural Fe(II) content strongly affects the reactivity towards H(2)O(2) decomposition and therefore RhB decolourization. The site density and sorption ability of RhB on surface may also influence the <span class="hlt">oxidation</span> performance in <span class="hlt">iron</span> <span class="hlt">oxide</span>/H(2)O(2) system. The <span class="hlt">iron</span> (II, III) <span class="hlt">oxide</span> catalysts exhibited low <span class="hlt">iron</span> leaching, good structural stability and no loss of performance in second reaction cycle. The sorption on the surface of <span class="hlt">iron</span> <span class="hlt">oxide</span> with catalytic <span class="hlt">oxidation</span> using hydrogen peroxide would be an effective <span class="hlt">oxidation</span> process for the contaminants.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25423717','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25423717"><span id="translatedtitle">[Neutrophilic lithotrophic <span class="hlt">iron-oxidizing</span> prokaryotes and their role in the biogeochemical processes of the <span class="hlt">iron</span> cycle].</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Dubinina, G A; Sorokina, A Iu</p> <p>2014-01-01</p> <p>Biology of lithotrophic neutrophilic <span class="hlt">iron-oxidizing</span> prokaryotes and their role in the processes of the biogeochemical cycle of <span class="hlt">iron</span> are discussed. This group of microorganisms is phylogenetically, taxonomically, and physiologically heterogeneous, comprising three metabolically different groups: aerobes, nitrate-dependent anaerobes, and phototrophs; the latter two groups have been revealed relatively recently. Their taxonomy and metabolism are described. Materials on the structure and functioning of the electron transport chain in the course of Fe(II) <span class="hlt">oxidation</span> by members of various physiological groups are discussed. Occurrence of <span class="hlt">iron</span> <span class="hlt">oxidizers</span> in freshwater and marine ecosystems, thermal springs, areas of hydrothermal activity, and underwater volcanic areas are considered. Molecular genetic techniques were used to determine the structure of <span class="hlt">iron-oxidizing</span> microbial communities in various natural ecosystems. Analysis of stable isotope fractioning of 56/54Fe in pure cultures and model experiments revealed predominance of biological <span class="hlt">oxidation</span> over abiotic ones in shallow aquatic habitats and mineral springs, which was especially pronounced under microaerobic conditions at the redox zone boundary. Discovery of anaerobic bacterial Fe(II) <span class="hlt">oxidation</span> resulted in development of new hypotheses concerning the possible role of microorganisms and the mechanisms of formation of the major <span class="hlt">iron</span> ore deposits in Precambrian and early Proterozoic epoch. Paleobiological data are presented on the microfossils and specific biomarkers retrieved from ancient ore samples and confirming involvement of anaerobic biogenic processes in their formation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25507440','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25507440"><span id="translatedtitle">[Neutrophilic lithotrophic <span class="hlt">iron-oxidizing</span> prokaryotes and their role in the biogeochemical processes of the <span class="hlt">iron</span> cycle].</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p></p> <p>2014-01-01</p> <p>Biology of lithotrophic neutrophilic <span class="hlt">iron-oxidizing</span> prokaryotes and their role in the processes of the biogeochemical cycle of <span class="hlt">iron</span> are discussed. This group of microorganisms is phylogenetically, taxonomically, and physiologically heterogeneous, comprising three metabolically different groups: aerobes, nitrate-dependent anaerobes, and phototrophs; the latter two groups have been revealed relatively recently. Their taxonomy and metabolism are described. Materials on the structure and functioning of the electron transport chain in the course of Fe(II) <span class="hlt">oxidation</span> by members of various physiological groups are discussed. Occurrence of <span class="hlt">iron</span> <span class="hlt">oxidizers</span> in freshwater and marine ecosystems, thermal springs, areas of hydrothermal activity, and underwater volcanic areas are considered. Molecular genetic techniques were used to determine the structure of <span class="hlt">iron-oxidizing</span> microbial communities in various natural ecosystems. Analysis of stable isotope fractioning of 56/54Fe in pure cultures and model experiments revealed predominance of biological <span class="hlt">oxidation</span> over abiotic ones in shallow aquatic habitats and mineral springs, which was especially pronounced under microaerobic conditions at the redox zone boundary. Discovery of anaerobic bacterial Fe(II) <span class="hlt">oxidation</span> resulted in development of new hypotheses concerning the possible role of microorganisms and the mechanisms of formation of the major <span class="hlt">iron</span> ore deposits in Precambrian and early Proterozoic epoch. Paleobiological data are presented on the microfossils and specific biomarkers retrieved from ancient ore samples and confirming involvement of anaerobic biogenic processes in their formation. PMID:25507440</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25423717','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25423717"><span id="translatedtitle">[Neutrophilic lithotrophic <span class="hlt">iron-oxidizing</span> prokaryotes and their role in the biogeochemical processes of the <span class="hlt">iron</span> cycle].</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Dubinina, G A; Sorokina, A Iu</p> <p>2014-01-01</p> <p>Biology of lithotrophic neutrophilic <span class="hlt">iron-oxidizing</span> prokaryotes and their role in the processes of the biogeochemical cycle of <span class="hlt">iron</span> are discussed. This group of microorganisms is phylogenetically, taxonomically, and physiologically heterogeneous, comprising three metabolically different groups: aerobes, nitrate-dependent anaerobes, and phototrophs; the latter two groups have been revealed relatively recently. Their taxonomy and metabolism are described. Materials on the structure and functioning of the electron transport chain in the course of Fe(II) <span class="hlt">oxidation</span> by members of various physiological groups are discussed. Occurrence of <span class="hlt">iron</span> <span class="hlt">oxidizers</span> in freshwater and marine ecosystems, thermal springs, areas of hydrothermal activity, and underwater volcanic areas are considered. Molecular genetic techniques were used to determine the structure of <span class="hlt">iron-oxidizing</span> microbial communities in various natural ecosystems. Analysis of stable isotope fractioning of 56/54Fe in pure cultures and model experiments revealed predominance of biological <span class="hlt">oxidation</span> over abiotic ones in shallow aquatic habitats and mineral springs, which was especially pronounced under microaerobic conditions at the redox zone boundary. Discovery of anaerobic bacterial Fe(II) <span class="hlt">oxidation</span> resulted in development of new hypotheses concerning the possible role of microorganisms and the mechanisms of formation of the major <span class="hlt">iron</span> ore deposits in Precambrian and early Proterozoic epoch. Paleobiological data are presented on the microfossils and specific biomarkers retrieved from ancient ore samples and confirming involvement of anaerobic biogenic processes in their formation. PMID:25423717</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..1710980E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..1710980E"><span id="translatedtitle"><span class="hlt">Iron</span> <span class="hlt">oxide</span> reduction in deep Baltic Sea sediments: the potential role of anaerobic <span class="hlt">oxidation</span> of methane</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Egger, Matthias; Slomp, Caroline P.; Dijkstra, Nikki; Sapart, Célia J.; Risgaard-Petersen, Nils; Kasten, Sabine; Riedinger, Natascha; Barker Jørgensen, Bo</p> <p>2015-04-01</p> <p>Methane is a powerful greenhouse gas and its emission from marine sediments to the atmosphere is largely controlled by anaerobic <span class="hlt">oxidation</span> of methane (AOM). Traditionally, sulfate is considered to be the most important electron acceptor for AOM in marine sediments. However, recent studies have shown that AOM may also be coupled to the reduction of <span class="hlt">iron</span> (Fe) <span class="hlt">oxides</span> (Beal et al., 2009; Riedinger et al., 2014; Egger et al., 2014). In the Baltic Sea, the transition from the Ancylus freshwater phase to the Littorina brackish/marine phase (A/L-transition) ca. 9-7 ka ago (Zillén et al., 2008) resulted in the accumulation of methanogenic brackish/marine sediments overlying Fe-<span class="hlt">oxide</span> rich lacustrine deposits. The downward diffusion of methane from the brackish/marine sediments into the lake sediments leads to an ideal diagenetic system to study a potential coupling between Fe <span class="hlt">oxide</span> reduction and methane <span class="hlt">oxidation</span>. Here, we use porewater and sediment geochemical data obtained at sites M0063 and M0065 during the IODP Baltic Sea Paleoenvironment Expedition 347 in 2013 to identify the potential mechanisms responsible for the apparent Fe <span class="hlt">oxide</span> reduction in the non-sulfidic limnic sediments below the A/L transition. In this presentation, we will review the various explanations for the elevated ferrous Fe in the porewater in the lake sediments and we will specifically address the potential role of the reaction of methane with Fe-<span class="hlt">oxides</span>. References: Beal E. J., House C. H. and Orphan V. J. (2009) Manganese- and <span class="hlt">iron</span>-dependent marine methane <span class="hlt">oxidation</span>. Science 325, 184-187. Egger M., Rasigraf O., Sapart C. J., Jilbert T., Jetten M. S. M., Röckmann T., van der Veen C., Banda N., Kartal B., Ettwig K. F. and Slomp C. P. (2014) <span class="hlt">Iron</span>-mediated anaerobic <span class="hlt">oxidation</span> of methane in brackish coastal sediments. Environ. Sci. Technol. 49, 277-283. Riedinger N., Formolo M. J., Lyons T. W., Henkel S., Beck A. and Kasten S. (2014) An inorganic geochemical argument for coupled anaerobic <span class="hlt">oxidation</span> of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/588831','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/588831"><span id="translatedtitle">Chemical characterization of <span class="hlt">iron</span> <span class="hlt">oxide</span> precipitates from wetlands constructed to treat polluted mine drainage</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Fish, C.L.; Partezana, J.M.; Hedin, R.S.</p> <p>1996-12-31</p> <p>The passive treatment of abandoned mine drainage using wetlands will produce a significant amount of <span class="hlt">iron</span> rich sludge which will require costly removal and disposal. An alternative to disposal may be the use of this <span class="hlt">iron</span> <span class="hlt">oxide</span> material as pigments which could defray some of these costs. In this research, <span class="hlt">iron</span> deposits from five alkaline mine drainage wetlands were collected and a series of standard tests were run. The tests included loss on ignition, moisture, pH, acid soluble metals, oil absorption, and water soluble matter. The results of these tests were compared to those achieved using commercially available natural and synthetic <span class="hlt">iron</span> <span class="hlt">oxides</span>. The results indicate that <span class="hlt">iron</span> <span class="hlt">oxides</span> from constructed wetlands have chemical properties that are intermediate to those of natural and synthetic <span class="hlt">iron</span> <span class="hlt">oxide</span> products.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/538250','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/538250"><span id="translatedtitle">Absorption of inorganic halides produced from Freon 12 by calcium carbonate containing <span class="hlt">iron</span>(III) <span class="hlt">oxide</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Imamura, Seiichiro; Matsuba, Yoichi; Yamada, Etsu; Takai, Kenji; Utani, Kazunori</p> <p>1997-09-01</p> <p>Inorganic halides produced by the catalytic decomposition of Freon 12 were fixed by calcium carbonate, which is the main component of limestone. <span class="hlt">Iron</span>(III) <span class="hlt">oxide</span>, which is present as a contaminant in limestone, promoted the absorption of the halides by calcium carbonate at low temperatures. The supposed action of <span class="hlt">iron</span>(III) <span class="hlt">oxide</span> was to first react with inorganic halides, forming <span class="hlt">iron</span> halides, and, then, transfer them to calcium carbonate to replace carbonate ion in a catalytic way. Thus, calcium carbonate containing <span class="hlt">iron</span> <span class="hlt">oxides</span> (limestone) can be used as an effective absorbent for the inorganic halogens produced during the decomposition of Freons.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/11871557','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/11871557"><span id="translatedtitle">Effect of <span class="hlt">oxide</span> formation mechanisms on lead adsorption by biogenic manganese (hydr)<span class="hlt">oxides</span>, <span class="hlt">iron</span> (hydr)<span class="hlt">oxides</span>, and their mixtures.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Nelson, Yarrow M; Lion, Leonard W; Shuler, Michael L; Ghiorse, William C</p> <p>2002-02-01</p> <p>The effects of <span class="hlt">iron</span> and manganese (hydr)<span class="hlt">oxide</span> formation processes on the trace metal adsorption properties of these metal (hydr)<span class="hlt">oxides</span> and their mixtures was investigated by measuring lead adsorption by <span class="hlt">iron</span> and manganese (hydr)<span class="hlt">oxides</span> prepared by a variety of methods. Amorphous <span class="hlt">iron</span> (hydr)<span class="hlt">oxide</span> formed by fast precipitation at pH 7.5 exhibited greater Pb adsorption (gamma(max) = 50 mmol of Pb/mol of Fe at pH 6.0) than <span class="hlt">iron</span> (hydr)<span class="hlt">oxide</span> formed by slow, diffusion-controlled <span class="hlt">oxidation</span> of Fe(II) at pH 4.5-7.0 or goethite. Biogenic manganese(III/IV) (hydr)<span class="hlt">oxide</span> prepared by enzymatic <span class="hlt">oxidation</span> of Mn(II) by the bacterium Leptothrix discophora SS-1 adsorbed five times more Pb (per mole of Mn) than an abiotic manganese (hydr)<span class="hlt">oxide</span> prepared by <span class="hlt">oxidation</span> of Mn(II) with permanganate, and 500-5000 times more Pb than pyrolusite <span class="hlt">oxides</span> (betaMnO2). X-ray crystallography indicated that biogenic manganese (hydr)<span class="hlt">oxide</span> and <span class="hlt">iron</span> (hydr)<span class="hlt">oxide</span> were predominantly amorphous or poorly crystalline and their X-ray diffraction patterns were not significantly affected by the presence of the other (hydr)<span class="hlt">oxide</span> during formation. When <span class="hlt">iron</span> and manganese (hydr)<span class="hlt">oxides</span> were mixed after formation, or for Mn biologically <span class="hlt">oxidized</span> with <span class="hlt">iron</span>(III) (hydr)<span class="hlt">oxide</span> present, observed Pb adsorption was similar to that expected for the mixture based on Langmuir parameters for the individual (hydr)<span class="hlt">oxides</span>. These results indicate that interactions in <span class="hlt">iron</span>/manganese (hydr)<span class="hlt">oxide</span> mixtures related to the formation process and sequence of formation such as site masking, alterations in specific surface area, or changes in crystalline structure either did not occur or had a negligible effect on Pb adsorption by the mixtures. PMID:11871557</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/11871557','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/11871557"><span id="translatedtitle">Effect of <span class="hlt">oxide</span> formation mechanisms on lead adsorption by biogenic manganese (hydr)<span class="hlt">oxides</span>, <span class="hlt">iron</span> (hydr)<span class="hlt">oxides</span>, and their mixtures.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Nelson, Yarrow M; Lion, Leonard W; Shuler, Michael L; Ghiorse, William C</p> <p>2002-02-01</p> <p>The effects of <span class="hlt">iron</span> and manganese (hydr)<span class="hlt">oxide</span> formation processes on the trace metal adsorption properties of these metal (hydr)<span class="hlt">oxides</span> and their mixtures was investigated by measuring lead adsorption by <span class="hlt">iron</span> and manganese (hydr)<span class="hlt">oxides</span> prepared by a variety of methods. Amorphous <span class="hlt">iron</span> (hydr)<span class="hlt">oxide</span> formed by fast precipitation at pH 7.5 exhibited greater Pb adsorption (gamma(max) = 50 mmol of Pb/mol of Fe at pH 6.0) than <span class="hlt">iron</span> (hydr)<span class="hlt">oxide</span> formed by slow, diffusion-controlled <span class="hlt">oxidation</span> of Fe(II) at pH 4.5-7.0 or goethite. Biogenic manganese(III/IV) (hydr)<span class="hlt">oxide</span> prepared by enzymatic <span class="hlt">oxidation</span> of Mn(II) by the bacterium Leptothrix discophora SS-1 adsorbed five times more Pb (per mole of Mn) than an abiotic manganese (hydr)<span class="hlt">oxide</span> prepared by <span class="hlt">oxidation</span> of Mn(II) with permanganate, and 500-5000 times more Pb than pyrolusite <span class="hlt">oxides</span> (betaMnO2). X-ray crystallography indicated that biogenic manganese (hydr)<span class="hlt">oxide</span> and <span class="hlt">iron</span> (hydr)<span class="hlt">oxide</span> were predominantly amorphous or poorly crystalline and their X-ray diffraction patterns were not significantly affected by the presence of the other (hydr)<span class="hlt">oxide</span> during formation. When <span class="hlt">iron</span> and manganese (hydr)<span class="hlt">oxides</span> were mixed after formation, or for Mn biologically <span class="hlt">oxidized</span> with <span class="hlt">iron</span>(III) (hydr)<span class="hlt">oxide</span> present, observed Pb adsorption was similar to that expected for the mixture based on Langmuir parameters for the individual (hydr)<span class="hlt">oxides</span>. These results indicate that interactions in <span class="hlt">iron</span>/manganese (hydr)<span class="hlt">oxide</span> mixtures related to the formation process and sequence of formation such as site masking, alterations in specific surface area, or changes in crystalline structure either did not occur or had a negligible effect on Pb adsorption by the mixtures.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25931604','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25931604"><span id="translatedtitle">Genome Sequence of the Acidophilic <span class="hlt">Iron</span> <span class="hlt">Oxidizer</span> Ferrimicrobium acidiphilum Strain T23T.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Eisen, Sebastian; Poehlein, Anja; Johnson, D Barrie; Daniel, Rolf; Schlömann, Michael; Mühling, Martin</p> <p>2015-04-30</p> <p>Extremely acidophilic <span class="hlt">iron-oxidizing</span> bacteria have largely been characterized for the phyla Proteobacteria and Nitrospira. Here, we report the draft genome of an <span class="hlt">iron-oxidizing</span> and -reducing heterotrophic mesophile of the Actinobacteria, Ferrimicrobium acidiphilum, which was isolated from an abandoned pyrite mine. The genome sequence comprises 3.08 Mb.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25283601','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25283601"><span id="translatedtitle">Non-heme <span class="hlt">iron</span> hydroperoxo species in superoxide reductase as a catalyst for <span class="hlt">oxidation</span> reactions.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Rat, S; Ménage, S; Thomas, F; Nivière, V</p> <p>2014-11-25</p> <p>The non-heme high-spin ferric <span class="hlt">iron</span> hydroperoxo species formed in superoxide reductase catalyzes <span class="hlt">oxidative</span> aldehyde deformylation through its nucleophilic character. This species also acts as an electrophile to catalyze oxygen atom transfer in sulfoxidation reactions, highlighting the <span class="hlt">oxidation</span> potential of non-heme <span class="hlt">iron</span> hydroperoxo species.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4417700','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4417700"><span id="translatedtitle">Genome Sequence of the Acidophilic <span class="hlt">Iron</span> <span class="hlt">Oxidizer</span> Ferrimicrobium acidiphilum Strain T23T</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Eisen, Sebastian; Poehlein, Anja; Johnson, D. Barrie; Daniel, Rolf; Schlömann, Michael</p> <p>2015-01-01</p> <p>Extremely acidophilic <span class="hlt">iron-oxidizing</span> bacteria have largely been characterized for the phyla Proteobacteria and Nitrospira. Here, we report the draft genome of an <span class="hlt">iron-oxidizing</span> and -reducing heterotrophic mesophile of the Actinobacteria, Ferrimicrobium acidiphilum, which was isolated from an abandoned pyrite mine. The genome sequence comprises 3.08 Mb. PMID:25931604</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26279467','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26279467"><span id="translatedtitle">Investigating the cytotoxicity of <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles in in vivo and in vitro studies.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ghasempour, Sarieh; Shokrgozar, Mohammad Ali; Ghasempour, Roghayeh; Alipour, Mohsen</p> <p>2015-10-01</p> <p>In recent years, <span class="hlt">iron</span> <span class="hlt">oxide</span> nanorods find a lot of applications including drug delivery, cell separation, hyperthermia and magnetic resonance imaging. In this study the cytotoxicity of <span class="hlt">iron</span> <span class="hlt">oxide</span> nanorods was evaluated based on mouse fibroblast cell behavior and wistar rat's liver and kidney function. At first for modification, nanorods were added to Dulbecco's modified Eagle's medium (DMEM) which contained a lot of sources of vitamins, amino acids, proteins in Fetal Bovine Serum (FBS). The MTT assay was employed for evaluating the toxic effects of 200 and 400 μg/mL modified and non-modified <span class="hlt">iron</span> <span class="hlt">oxide</span> nanorods on L929 mouse fibroblast cells in a 24h period. Changes in cell granularity and size as well as cell cycle were investigated using flow cytometry. Moreover liver and kidney function test and serum <span class="hlt">iron</span> level measurement were performed 24h after the injection of modified <span class="hlt">iron</span> <span class="hlt">oxide</span> nanorods via the tail peripheral vein of wistar rats. Results indicated that greater concentration of modified <span class="hlt">iron</span> <span class="hlt">oxide</span> nanorods had no significant effect on cell viability while greater concentration of non-modified <span class="hlt">iron</span> <span class="hlt">oxide</span> nanorods significantly decreased cell viability. Modified <span class="hlt">iron</span> <span class="hlt">oxide</span> nanorods did not have significant effects on cell cycle. The results of liver and kidney function tests did not differ significantly while a significant increase in serum <span class="hlt">iron</span> level was observed. After H&E staining of slices, there were no changes on morphology of rat's kidney and liver cells. This study suggests that short-time use of 200 and 400 μg/mL <span class="hlt">iron</span> <span class="hlt">oxide</span> nanorods are probably safe. Further studies are needed for investigation of toxic effects of different concentrations, coatings, and exposure time periods of <span class="hlt">iron</span> <span class="hlt">oxide</span> nanorods. PMID:26279467</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20516004','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20516004"><span id="translatedtitle">Recovery of zinc from leach residues with minimum <span class="hlt">iron</span> dissolution using <span class="hlt">oxidative</span> leaching.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Alizadeh, Reza; Rashchi, Fereshteh; Vahidi, Ehsan</p> <p>2011-02-01</p> <p>Leaching was performed to recover zinc from a zinc leach residue which contained 9.87% Zn and 4.93% Fe. During sulfuric acid leaching, Fe was dissolved as well as Zn which can reduce the Zn extraction efficiency. Leaching the residue in the presence of an <span class="hlt">oxidizing</span> reagent such as hydrogen peroxide or manganese dioxide significantly reduced the <span class="hlt">iron</span> content of the leach liquor. Effect of pH, temperature, solid/liquid ratio, reaction time and hydrogen peroxide or manganese dioxide concentration on the recovery of zinc and <span class="hlt">iron</span> in non-<span class="hlt">oxidative</span> and <span class="hlt">oxidative</span> leaching conditions were investigated. By using the optimum <span class="hlt">oxidative</span> leaching conditions, <span class="hlt">iron</span> recovery reduced from 70% in non-<span class="hlt">oxidative</span> leaching to 0.4 and 5% in the presence of MnO(2) and H(2)O(2), respectively, with acceptable Zn recovery. This reduction in the <span class="hlt">iron</span> content was due to the different <span class="hlt">iron</span> compounds formed at different conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25498641','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25498641"><span id="translatedtitle"><span class="hlt">Iron</span> <span class="hlt">oxide</span>/cassava starch-supported Ziegler-Natta catalysts for in situ ethylene polymerization.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Chancharoenrith, Sittikorn; Kamonsatikul, Choavarit; Namkajorn, Montree; Kiatisevi, Supavadee; Somsook, Ekasith</p> <p>2015-03-01</p> <p><span class="hlt">Iron</span> <span class="hlt">oxide</span> nanoparticles were used as supporters for in situ polymerization to produce polymer nanocomposites with well-dispersed fillers in polymer matrix. <span class="hlt">Iron</span> <span class="hlt">oxide</span> could be sustained as colloidal solutions by cassava starch to produce a good dispersion of <span class="hlt">iron</span> <span class="hlt">oxide</span> in the matrix. New supports based on <span class="hlt">iron</span> <span class="hlt">oxide</span>/cassava starch or cassava starch for Ziegler-Natta catalysts were utilized as heterogeneous supporters for partially hydrolyzed triethylaluminum. Then, TiCl4 was immobilized on the supports as catalysts for polymerization of ethylene. High-density polyethylene (HDPE) composites were obtained by the synthesized catalysts. A good dispersion of <span class="hlt">iron</span> <span class="hlt">oxide</span>/cassava starch particles was observed in the synthesized polymer matrix promoting to good mechanical properties of HDPE. PMID:25498641</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_14 --> <div id="page_15" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="281"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/20537238','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/20537238"><span id="translatedtitle">Preparation of <span class="hlt">iron</span> <span class="hlt">oxide</span>-entrapped chitosan nanoparticles for stem cell labeling.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Chaleawlert-Umpon, Saowaluk; Mayen, Varissaporn; Manotham, Krissanapong; Pimpha, Nuttaporn</p> <p>2010-01-01</p> <p>This study intended to prepare <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticle-entrapped chitosan (CS) nanoparticles for stem cell labeling. The nanoparticles were synthesized by polymerizing <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticle-associated methacrylic acid monomer in the presence of CS. TEM revealed that the well-defined <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles were successfully encapsulated inside the CS nanoparticles. The effect of CS at different [NH(2)]/[COOH] molar ratios on particle size, surface charge, thermal stability and magnetic properties was determined systematically. Internalization and localization of the coated nanoparticles were evaluated by atomic absorption spectrometry and confocal laser scanning microscopy. The Kusa O cell line was chosen as a stem cell model. Interestingly, the uptake of <span class="hlt">iron</span> <span class="hlt">oxide</span>-entrapped CS nanoparticles was remarkably enhanced under magnetization and the nanoparticles were mostly located inside cellular compartments. It can be concluded that the <span class="hlt">iron</span> <span class="hlt">oxide</span>-entrapped CS nanoparticles have a strong potential for stem cell labeling. PMID:20537238</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17714754','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17714754"><span id="translatedtitle"><span class="hlt">Iron</span>(3) <span class="hlt">oxide</span>-based nanoparticles as catalysts in advanced organic aqueous <span class="hlt">oxidation</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zelmanov, Grigory; Semiat, Raphael</p> <p>2008-01-01</p> <p>Water contaminated with dissolved organic matter is an important issue to resolve for all-purpose uses. The catalytic behavior of <span class="hlt">iron</span>-based nanocatalysts was investigated for the treatment of contaminated water in the advanced chemical <span class="hlt">oxidation</span> process. In this study, typical organic contaminants, such as ethylene glycol and phenol, were chosen to simulate common contaminants. It was shown that the two substances are efficiently destroyed by the Fenton-like reaction using <span class="hlt">iron</span>(3) <span class="hlt">oxide</span>-based nanocatalysts in the presence of hydrogen peroxide without the need for UV or visible radiation sources at room temperature. A strong effect of nanocatalyst concentration on reaction rate was shown. The kinetic reaction was found and the reaction rate coefficient k was calculated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JMMM..388...49D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JMMM..388...49D"><span id="translatedtitle"><span class="hlt">Iron</span> <span class="hlt">oxide</span> nanoparticles for magnetically assisted patterned coatings</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dodi, Gianina; Hritcu, Doina; Draganescu, Dan; Popa, Marcel I.</p> <p>2015-08-01</p> <p><span class="hlt">Iron</span> <span class="hlt">oxide</span> nanoparticles able to magnetically assemble during the curing stage of a polymeric support to create micro-scale surface protuberances in a controlled manner were prepared and characterized. The bare Fe3O4 particles were obtained by two methods: co-precipitation from an aqueous solution containing Fe3+/Fe2+ ions with a molar ratio of 2:1 and partial <span class="hlt">oxidation</span> of ferrous ions in alkaline conditions. The products were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and magnetization measurement. They were subsequently functionalized using oleic acid, sodium oleate, or non-ionic surfactant mixtures with various hydrophilic to lipophilic balance (HLB) values. Composite nanoparticle-polymer films prepared by spraying were deposited and cured by drying on glass slides under a static magnetic field in the range of 1.5-5.5 mT. Magnetic field generated surface roughness was evidenced by optical and scanning electron microscopy. The optimum hierarchical patterning was obtained with the nanoparticles produced by partial <span class="hlt">oxidation</span> and functionalized with hydrophobic surfactants. Possible applications may include ice-phobic composite coatings.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016MMTA...47.4760P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016MMTA...47.4760P"><span id="translatedtitle">Processing, Microstructure, and <span class="hlt">Oxidation</span> Behavior of <span class="hlt">Iron</span> Foams</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Park, Hyeji; Noh, Yoonsook; Choi, Hyelim; Hong, Kicheol; Kwon, Kyungjung; Choe, Heeman</p> <p>2016-09-01</p> <p>With its historically long popularity in major structural applications, the use of <span class="hlt">iron</span> (Fe) has also recently begun to be explored as an advanced functional material. For this purpose, it is more advantageous to use Fe as a porous structure, simply because it can provide a greater surface area and a higher reaction rate. This study uses a freeze-casting method, which consists of simple and low-cost processing steps, to produce Fe foam with a mean pore size of 10 μm. We examine the influences of various parameters ( i.e., mold bottom temperature, powder content, and sintering time) on the processing of Fe foam, along with its <span class="hlt">oxidation</span> kinetics at 823 K (550 °C) with various heat-treatment times. We confirm that Fe2O3 and Fe3O4 <span class="hlt">oxide</span> layers are successfully formed on the surface of Fe foam. With the Fe <span class="hlt">oxide</span> layers as an active anode material, the Fe foam can potentially be used as a three-dimensional anode current collector for an advanced lithium-ion battery.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1005880','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1005880"><span id="translatedtitle">High pressure effects on the <span class="hlt">iron</span> <span class="hlt">iron</span> <span class="hlt">oxide</span> and nickel nickel <span class="hlt">oxide</span> oxygen fugacity buffers</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Campbell, Andrew J; Danielson, Lisa; Righter, Kevin; Seagle, Christopher T; Wang, Yanbin; Prakapenka, Vitali B</p> <p>2009-09-25</p> <p>The chemical potential of oxygen in natural and experimental samples is commonly reported relative to a specific oxygen fugacity (fO{sub 2}) buffer. These buffers are precisely known at 1 bar, but under high pressures corresponding to the conditions of the deep Earth, oxygen fugacity buffers are poorly calibrated. Reference (1 bar) fO{sub 2} buffers can be integrated to high pressure conditions by integrating the difference in volume between the solid phases, provided that their equations of state are known. In this work, the equations of state and volume difference between the metal-<span class="hlt">oxide</span> pairs Fe-FeO and Ni-NiO were measured using synchrotron X-ray diffraction in a multi-anvil press and laser heated diamond anvil cells. The results were used to construct high pressure fO{sub 2} buffer curves for these systems. The difference between the Fe-FeO and Ni-NiO buffers is observed to decrease significantly, by several log units, over 80 GPa. The results can be used to improve interpretation of high pressure experiments, specifically Fe-Ni exchange between metallic and <span class="hlt">oxide</span> phases.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23224777','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23224777"><span id="translatedtitle">Handling of <span class="hlt">iron</span> <span class="hlt">oxide</span> and silver nanoparticles by astrocytes.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hohnholt, Michaela C; Geppert, Mark; Luther, Eva M; Petters, Charlotte; Bulcke, Felix; Dringen, Ralf</p> <p>2013-02-01</p> <p>Metal-containing nanoparticles (NPs) are currently used for various biomedical applications. Since such NPs are able to enter the brain, the cells of this organ have to deal with NPs and with NP-derived metal ions. In brain, astrocytes are considered to play a key function in regulating metal homeostasis and in protecting other brain cells against metal toxicity. Thus, among the different types of brain cells, especially astrocytes are of interest regarding the uptake and the handling of metal-containing NPs. This article summarizes the current knowledge on the consequences of an exposure of astrocytes to NPs. Special focus will be given to magnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles (IONPs) and silver nanoparticles (AgNPs), since the biocompatibility of these NPs has been studied for astrocytes in detail. Cultured astrocytes efficiently accumulate IONPs and AgNPs in a time-, concentration- and temperature-dependent manner by endocytotic processes. Astrocytes are neither acutely damaged by the exposure to high concentrations of NPs nor by the prolonged intracellular presence of large amounts of accumulated NPs. Although metal ions are liberated from accumulated NPs, NP-derived <span class="hlt">iron</span> and silver ions are not exported from astrocytes but are rather stored in proteins such as ferritin and metallothioneins which are synthesized in NP-treated astrocytes. The efficient accumulation of large amounts of metal-containing NPs and the upregulation of proteins that safely store NP-derived metal ions suggest that astrocytes protect the brain against the potential toxicity of metal-containing NPs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26821173','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26821173"><span id="translatedtitle">Multifunctional Hydrogel Microparticles by <span class="hlt">Polymer-Assisted</span> Photolithography.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Li, Bin; He, Muhan; Ramirez, Lisa; George, Justin; Wang, Jun</p> <p>2016-02-17</p> <p>Although standard lithography has been the most common technique in micropatterning, <span class="hlt">ironically</span> it has not been adopted to produce multifunctional hydrogel microparticles, which are highly useful for bioassays. We address this issue by developing a negative photoresist-like polymer system, which is basically comprised of polyethylene glycol (PEG) triacrylate as cross-linking units and long-chain polyvinylpyrrolidone (PVP) as the supporting scaffold. We leverage standard lithography to manufacture multilayer microparticles that are intrinsically hydrophilic, low-autofluorescent, and chemically reactive. The versatility of the microparticles is demonstrated to be color-encoded, pore-controllable, bioactive, and potentially used as a DNA bioassay.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.B51A0483B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.B51A0483B"><span id="translatedtitle">Identification of a membrane cytochrome c from neutrophilic, <span class="hlt">iron-oxidizing</span> Mariprofundus ferrooxydans, strain PV-1</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Barco, R. A.; Zhong, J.; Ramirez, G. A.; Reese, B. K.; Edwards, K. J.</p> <p>2012-12-01</p> <p>Neutrophilic-<span class="hlt">iron</span> <span class="hlt">oxidizing</span> bacteria (FeOB) are a group of bacteria that can <span class="hlt">oxidize</span> <span class="hlt">iron</span> at -or near neutral pH, making them relevant in habitats with naturally high levels of reduced <span class="hlt">iron</span> (i.e. Fe2+) such as hydrothermal vents. In the ocean, microorganisms in the Mariprofundus genus (zeta- Proteobacteria) are the only known organisms to chemolithoautotrophically <span class="hlt">oxidize</span> <span class="hlt">iron</span>. In order to identify the active bacterial <span class="hlt">oxidation</span> of <span class="hlt">iron</span> in the environment (i.e. in the deep biosphere), biomarkers for this functionality are needed. The aim of this study is to confirm the expression of potential functional biomarkers that are diagnostic of neutrophilic bacterial <span class="hlt">iron-oxidation</span>. To this end, Mariprofundus ferrooxydans, strain PV-1 was cultivated in large batches and its proteins extracted via a methodology to circumvent protein binding to filamentous material. Proteins were assayed for redox-activity and for <span class="hlt">iron-oxidation</span> activity. The bands of the gel that showed activity were analyzed via LC-MS/MS for identification of peptides and subsequently protein-matched to the M. ferrooxydans proteome database. The results indicate that a membrane cytochrome c with homology to the <span class="hlt">iron-oxidizing</span> Cyt572 from Leptospirillum Group II is expressed in M. ferrooxydans when it is active. Other proteins associated with the electron transport chain of M. ferroxydans such as cbb3-type cytochrome oxidase subunits were identified and validated separately through reverse transcription followed by PCR amplification.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003APS..MAR.Y9011W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003APS..MAR.Y9011W"><span id="translatedtitle">Ferromagnetic Resonance of Superparamagnetic <span class="hlt">Iron</span> <span class="hlt">Oxide</span> Nanoparticles for Biomedical Applications</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wosik, Jaroslaw; Xue, Lian; Xie, Lei-Ming; Chan, Dan</p> <p>2003-03-01</p> <p>Ferromagnetic Resonance (FMR) techniques were used to investigate superparamagnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> (SPIO) nanoparticles (NP) with different coatings and sizes ranging from 5 to 50 nm in diameter. The samples were synthesized by standard procedures with or without coating and fractionated by differential centrifugations to generate particles of different sizes. In order to improve detection sensitivity of pathological tissue changes such as atherosclerosis, smaller particles of less than 10 nm were selected for contrast-enhanced magnetic resonance imaging (MRI). We have investigated uncoated, lipid encapsulated and dextran coated SPIO samples in liquid suspension, dry, and in mixed-with-wax forms. The angular dependence of the FMR of NP with easy axes aligned and frozen in wax was measured. Shapes and shifts of FMR lines for each sample was analyzed for size and anisotropy. Examples of rabbit's aorta MRI T2-weigted images showing proton relaxation time T2 shortening due to the pretreatment with SPIO will be presented and discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JMMM..374..205Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JMMM..374..205Y"><span id="translatedtitle">Preparation of polylysine-modified superparamagnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yang, Gao; Zhang, Baolin; Wang, Jun; Xie, Songbo; Li, Xuan</p> <p>2015-01-01</p> <p>Polylysine (PLL) coated <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles (SPIONs) have potential in biomedical application. In the present work PEG coated SPIONs (PEG-SPIONs) with the particle size of 9.4±1.4 nm were synthesized by thermal decomposition of Fe(acac)3 in PEG, and then coated with PLL (PLL/PEG-SPIONs). The PEG-SPIONs and PLL/PEG-SPIONs were superparamagnetic with the saturation magnetization of 53 and 44 emu/g, respectively. The hydrodynamic diameter of PEG-SPIONs in deionized water was 18.8 nm, which increased to 21.3-28.2 nm after mixing with different amount of PLL. The zeta potentials of PLL/PEG-SPIONs were -8.9 - -3.4 mV which were changing with time. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analyses indicated that PLL was attached to the PEG-SPIONs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JTST...24.1487N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JTST...24.1487N"><span id="translatedtitle">Photocatalytic <span class="hlt">Iron</span> <span class="hlt">Oxide</span> Coatings Produced by Thermal Spraying Process</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Navidpour, A. H.; Salehi, M.; Amirnasr, M.; Salimijazi, H. R.; Azarpour Siahkali, M.; Kalantari, Y.; Mohammadnezhad, M.</p> <p>2015-12-01</p> <p>Recently, hematite coatings with semiconductor properties have received attention for photocatalytic applications. In this study, plasma and flame spraying techniques were used for hematite deposition on 316 stainless steel plates. X-ray diffraction was used for phase composition analysis, and methylene blue was used as an organic pollutant to evaluate the photocatalytic activity of thermally sprayed coatings. The results showed that all these coatings could act under visible-light irradiation but the one deposited by flame spraying at 20 cm stand-off distance showed the highest photocatalytic activity. The results showed that wavelength of the light source and pH of the solution affected the photocatalytic activity significantly. It was also shown that thermally sprayed <span class="hlt">iron</span> <span class="hlt">oxide</span> coatings could have a high photo-absorption ability, which could positively affect the photocatalytic activity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6282263','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6282263"><span id="translatedtitle">System for recycling char in <span class="hlt">iron</span> <span class="hlt">oxide</span> reducing kilns</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Baker, A.C.; Keran, V.P.</p> <p>1983-03-08</p> <p>A method and means for improving the efficiency of the process for directly reducing ore containing <span class="hlt">iron</span> <span class="hlt">oxide</span> in a rotary kiln using a solid carbonaceous reducing agent, such as coal, introduced from the ore feed and discharge ends of the kiln, as both fuel and reductant, is disclosed wherein the charred coal or char found in the discharge product is recycled into the process at the discharge end of the kiln rather than the feed end as in the prior art. In particular, the recovered char, both coarse and finer particles, are transported to a recycle bin from which they are returned at a preselected rate to the kiln process by being injected along with the coal blown into the discharge end of the kiln. Alternatively, the recycle char alone may be fed without any coal at the discharge end of the kiln.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4183648','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4183648"><span id="translatedtitle">Heterobifunctional PEG Ligands for Bioconjugation Reactions on <span class="hlt">Iron</span> <span class="hlt">Oxide</span> Nanoparticles</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Bloemen, Maarten; Van Stappen, Thomas; Willot, Pieter; Lammertyn, Jeroen; Koeckelberghs, Guy; Geukens, Nick; Gils, Ann; Verbiest, Thierry</p> <p>2014-01-01</p> <p>Ever since <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles have been recognized as promising scaffolds for biomedical applications, their surface functionalization has become even more important. We report the synthesis of a novel polyethylene glycol-based ligand that combines multiple advantageous properties for these applications. The ligand is covalently bound to the surface via a siloxane group, while its polyethylene glycol backbone significantly improves the colloidal stability of the particle in complex environments. End-capping the molecule with a carboxylic acid introduces a variety of coupling chemistry possibilities. In this study an antibody targeting plasminogen activator inhibitor-1 was coupled to the surface and its presence and binding activity was assessed by enzyme-linked immunosorbent assay and surface plasmon resonance experiments. The results indicate that the ligand has high potential towards biomedical applications where colloidal stability and advanced functionality is crucial. PMID:25275378</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4661819','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4661819"><span id="translatedtitle">Genotoxicity of Superparamagnetic <span class="hlt">Iron</span> <span class="hlt">Oxide</span> Nanoparticles in Granulosa Cells</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Pöttler, Marina; Staicu, Andreas; Zaloga, Jan; Unterweger, Harald; Weigel, Bianca; Schreiber, Eveline; Hofmann, Simone; Wiest, Irmi; Jeschke, Udo; Alexiou, Christoph; Janko, Christina</p> <p>2015-01-01</p> <p>Nanoparticles that are aimed at targeting cancer cells, but sparing healthy tissue provide an attractive platform of implementation for hyperthermia or as carriers of chemotherapeutics. According to the literature, diverse effects of nanoparticles relating to mammalian reproductive tissue are described. To address the impact of nanoparticles on cyto- and genotoxicity concerning the reproductive system, we examined the effect of superparamagnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles (SPIONs) on granulosa cells, which are very important for ovarian function and female fertility. Human granulosa cells (HLG-5) were treated with SPIONs, either coated with lauric acid (SEONLA) only, or additionally with a protein corona of bovine serum albumin (BSA; SEONLA-BSA), or with dextran (SEONDEX). Both micronuclei testing and the detection of γH2A.X revealed no genotoxic effects of SEONLA-BSA, SEONDEX or SEONLA. Thus, it was demonstrated that different coatings of SPIONs improve biocompatibility, especially in terms of genotoxicity towards cells of the reproductive system. PMID:26540051</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014SPIE.8955E..1PT&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014SPIE.8955E..1PT&link_type=ABSTRACT"><span id="translatedtitle"><span class="hlt">Iron</span> <span class="hlt">oxide</span> nanoparticles in different modifications for antimicrobial phototherapy</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tuchina, Elena S.; Kozina, Kristina V.; Shelest, Nikita A.; Kochubey, Vyacheslav I.; Tuchin, Valery V.</p> <p>2014-03-01</p> <p>The main goal of this study was to investigate the sensitivity of microorganisms to combined action of blue light and <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles. Two strains of Staphylococcus aureus - methicillin-sensitive and meticillin-resistant were used. As a blue light source LED with spectral maximum at 405 nm was taken. The light exposure was ranged from 5 to 30 min. The Fe2O3 (diameter ˜27 nm), Fe3O4 nanoparticles (diameter ˜19 nm), and composite Fe2O3/TiO2 nanoparticles (diameter ˜100 nm) were synthesized. It was shown that irradiation by blue light caused from 20% to 88% decrease in the number of microorganisms treated with nanoparticles. Morphological changes in bacterial cells after phototreatment were analyzed using scanning electron microscope.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18097492','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18097492"><span id="translatedtitle">Growth of <span class="hlt">iron</span> cobalt <span class="hlt">oxides</span> by atomic layer deposition.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lie, Martin; Barnholt Klepper, Karina; Nilsen, Ola; Fjellvåg, Helmer; Kjekshus, Arne</p> <p>2008-01-14</p> <p>Thin films of <span class="hlt">iron</span> cobalt <span class="hlt">oxides</span> with spinel-type structure are made by the atomic layer deposition (ALD) technique using Fe(thd)3 (Hthd = 2,2,6,6-tetramethylheptane-3,5-dione), Co(thd)2, and ozone as precursors. Pulse parameters for ALD-type growth are established and such growth can be achieved at deposition temperatures between 185 and 310 degrees C. Films have been deposited on amorphous soda-lime glass and single-crystalline substrates of Si(100), MgO(100), and alpha-Al2O3(001) which all provide crystalline films, but with various orientations and crystallite sizes. Application of an external magnetic field during the film growth does not influence film growth characteristics (growth rate, crystallinity, topography etc.). Magnetization data are reported for phase-pure films of spinel-type structure with composition Fe2CoO4.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JMMM..414..105L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JMMM..414..105L"><span id="translatedtitle">Transformation of <span class="hlt">iron</span> <span class="hlt">oxides</span> on PI electrospun membranes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, Penggang; Lv, Fengzhu; Liu, Leipeng; Ding, Ling; Zhang, Yihe</p> <p>2016-09-01</p> <p><span class="hlt">Iron</span> <span class="hlt">oxides</span>/PI fiber membranes, especially magnetic PI membranes, are important flexible porous materials available application in the field of wave absorption, magnetic recording, membrane separation and catalysts. Therefore, α-Fe2O3 loaded PI composite fibers were prepared by electrospinning of poly(amic acid) PAA solution followed by loading Fe3+ on the PAA membrane by ion-exchange and then imidization. Then the α-Fe2O3 on PI membrane were reduced by H2 to give magnetic PI membranes. The content of α-Fe2O3 and Fe3O4 on PI can be controlled by adjustment the ion-exchange time. The saturation magnetization of the composite membranes can reach up to 4 emu/g and the final composite membranes have magnetic response ability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016Nanot..27o5706G&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016Nanot..27o5706G&link_type=ABSTRACT"><span id="translatedtitle">NMR relaxation induced by <span class="hlt">iron</span> <span class="hlt">oxide</span> particles: testing theoretical models</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gossuin, Y.; Orlando, T.; Basini, M.; Henrard, D.; Lascialfari, A.; Mattea, C.; Stapf, S.; Vuong, Q. L.</p> <p>2016-04-01</p> <p>Superparamagnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> particles find their main application as contrast agents for cellular and molecular magnetic resonance imaging. The contrast they bring is due to the shortening of the transverse relaxation time T 2 of water protons. In order to understand their influence on proton relaxation, different theoretical relaxation models have been developed, each of them presenting a certain validity domain, which depends on the particle characteristics and proton dynamics. The validation of these models is crucial since they allow for predicting the ideal particle characteristics for obtaining the best contrast but also because the fitting of T 1 experimental data by the theory constitutes an interesting tool for the characterization of the nanoparticles. In this work, T 2 of suspensions of <span class="hlt">iron</span> <span class="hlt">oxide</span> particles in different solvents and at different temperatures, corresponding to different proton diffusion properties, were measured and were compared to the three main theoretical models (the motional averaging regime, the static dephasing regime, and the partial refocusing model) with good qualitative agreement. However, a real quantitative agreement was not observed, probably because of the complexity of these nanoparticulate systems. The Roch theory, developed in the motional averaging regime (MAR), was also successfully used to fit T 1 nuclear magnetic relaxation dispersion (NMRD) profiles, even outside the MAR validity range, and provided a good estimate of the particle size. On the other hand, the simultaneous fitting of T 1 and T 2 NMRD profiles by the theory was impossible, and this occurrence constitutes a clear limitation of the Roch model. Finally, the theory was shown to satisfactorily fit the deuterium T 1 NMRD profile of superparamagnetic particle suspensions in heavy water.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4632710','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4632710"><span id="translatedtitle">Mutagenic Effects of <span class="hlt">Iron</span> <span class="hlt">Oxide</span> Nanoparticles on Biological Cells</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Dissanayake, Niluka M.; Current, Kelley M.; Obare, Sherine O.</p> <p>2015-01-01</p> <p>In recent years, there has been an increased interest in the design and use of <span class="hlt">iron</span> <span class="hlt">oxide</span> materials with nanoscale dimensions for magnetic, catalytic, biomedical, and electronic applications. The increased manufacture and use of <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles (IONPs) in consumer products as well as industrial processes is expected to lead to the unintentional release of IONPs into the environment. The impact of IONPs on the environment and on biological species is not well understood but remains a concern due to the increased chemical reactivity of nanoparticles relative to their bulk counterparts. This review article describes the impact of IONPs on cellular genetic components. The mutagenic impact of IONPs may damage an organism’s ability to develop or reproduce. To date, there has been experimental evidence of IONPs having mutagenic interactions on human cell lines including lymphoblastoids, fibroblasts, microvascular endothelial cells, bone marrow cells, lung epithelial cells, alveolar type II like epithelial cells, bronchial fibroblasts, skin epithelial cells, hepatocytes, cerebral endothelial cells, fibrosarcoma cells, breast carcinoma cells, lung carcinoma cells, and cervix carcinoma cells. Other cell lines including the Chinese hamster ovary cells, mouse fibroblast cells, murine fibroblast cells, Mytilus galloprovincialis sperm cells, mice lung cells, murine alveolar macrophages, mice hepatic and renal tissue cells, and vero cells have also shown mutagenic effects upon exposure to IONPs. We further show the influence of IONPs on microorganisms in the presence and absence of dissolved organic carbon. The results shed light on the transformations IONPs undergo in the environment and the nature of the potential mutagenic impact on biological cells. PMID:26437397</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26933908','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26933908"><span id="translatedtitle">NMR relaxation induced by <span class="hlt">iron</span> <span class="hlt">oxide</span> particles: testing theoretical models.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gossuin, Y; Orlando, T; Basini, M; Henrard, D; Lascialfari, A; Mattea, C; Stapf, S; Vuong, Q L</p> <p>2016-04-15</p> <p>Superparamagnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> particles find their main application as contrast agents for cellular and molecular magnetic resonance imaging. The contrast they bring is due to the shortening of the transverse relaxation time T 2 of water protons. In order to understand their influence on proton relaxation, different theoretical relaxation models have been developed, each of them presenting a certain validity domain, which depends on the particle characteristics and proton dynamics. The validation of these models is crucial since they allow for predicting the ideal particle characteristics for obtaining the best contrast but also because the fitting of T 1 experimental data by the theory constitutes an interesting tool for the characterization of the nanoparticles. In this work, T 2 of suspensions of <span class="hlt">iron</span> <span class="hlt">oxide</span> particles in different solvents and at different temperatures, corresponding to different proton diffusion properties, were measured and were compared to the three main theoretical models (the motional averaging regime, the static dephasing regime, and the partial refocusing model) with good qualitative agreement. However, a real quantitative agreement was not observed, probably because of the complexity of these nanoparticulate systems. The Roch theory, developed in the motional averaging regime (MAR), was also successfully used to fit T 1 nuclear magnetic relaxation dispersion (NMRD) profiles, even outside the MAR validity range, and provided a good estimate of the particle size. On the other hand, the simultaneous fitting of T 1 and T 2 NMRD profiles by the theory was impossible, and this occurrence constitutes a clear limitation of the Roch model. Finally, the theory was shown to satisfactorily fit the deuterium T 1 NMRD profile of superparamagnetic particle suspensions in heavy water.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_15 --> <div id="page_16" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="301"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26933908','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26933908"><span id="translatedtitle">NMR relaxation induced by <span class="hlt">iron</span> <span class="hlt">oxide</span> particles: testing theoretical models.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gossuin, Y; Orlando, T; Basini, M; Henrard, D; Lascialfari, A; Mattea, C; Stapf, S; Vuong, Q L</p> <p>2016-04-15</p> <p>Superparamagnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> particles find their main application as contrast agents for cellular and molecular magnetic resonance imaging. The contrast they bring is due to the shortening of the transverse relaxation time T 2 of water protons. In order to understand their influence on proton relaxation, different theoretical relaxation models have been developed, each of them presenting a certain validity domain, which depends on the particle characteristics and proton dynamics. The validation of these models is crucial since they allow for predicting the ideal particle characteristics for obtaining the best contrast but also because the fitting of T 1 experimental data by the theory constitutes an interesting tool for the characterization of the nanoparticles. In this work, T 2 of suspensions of <span class="hlt">iron</span> <span class="hlt">oxide</span> particles in different solvents and at different temperatures, corresponding to different proton diffusion properties, were measured and were compared to the three main theoretical models (the motional averaging regime, the static dephasing regime, and the partial refocusing model) with good qualitative agreement. However, a real quantitative agreement was not observed, probably because of the complexity of these nanoparticulate systems. The Roch theory, developed in the motional averaging regime (MAR), was also successfully used to fit T 1 nuclear magnetic relaxation dispersion (NMRD) profiles, even outside the MAR validity range, and provided a good estimate of the particle size. On the other hand, the simultaneous fitting of T 1 and T 2 NMRD profiles by the theory was impossible, and this occurrence constitutes a clear limitation of the Roch model. Finally, the theory was shown to satisfactorily fit the deuterium T 1 NMRD profile of superparamagnetic particle suspensions in heavy water. PMID:26933908</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012LPI....43.1940P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012LPI....43.1940P"><span id="translatedtitle"><span class="hlt">Iron</span> (Oxyhydr)<span class="hlt">Oxide</span> Biosignatures in the Brushy Basin Member of the Jurassic Morrison Formation, Colorado Plateau, USA: Analog for Martian Diagenetic <span class="hlt">Iron</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Potter-McIntyre, S. L.; Chan, M. A.; McPherson, B. J.</p> <p>2012-03-01</p> <p><span class="hlt">Iron</span> precipitates in modern microbial mats compared with <span class="hlt">iron</span> cements in Jurassic alkaline saline lake sediments show that morphological and chemical biosignatures are present and preserved in <span class="hlt">oxidized</span>, evaporative environments analogous to Mars.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25999927','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25999927"><span id="translatedtitle">Isolation of microorganisms involved in reduction of crystalline <span class="hlt">iron</span>(III) <span class="hlt">oxides</span> in natural environments.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hori, Tomoyuki; Aoyagi, Tomo; Itoh, Hideomi; Narihiro, Takashi; Oikawa, Azusa; Suzuki, Kiyofumi; Ogata, Atsushi; Friedrich, Michael W; Conrad, Ralf; Kamagata, Yoichi</p> <p>2015-01-01</p> <p>Reduction of crystalline Fe(III) <span class="hlt">oxides</span> is one of the most important electron sinks for organic compound <span class="hlt">oxidation</span> in natural environments. Yet the limited number of isolates makes it difficult to understand the physiology and ecological impact of the microorganisms involved. Here, two-stage cultivation was implemented to selectively enrich and isolate crystalline <span class="hlt">iron</span>(III) <span class="hlt">oxide</span> reducing microorganisms in soils and sediments. Firstly, <span class="hlt">iron</span> reducers were enriched and other untargeted eutrophs were depleted by 2-years successive culture on a crystalline ferric <span class="hlt">iron</span> <span class="hlt">oxide</span> (i.e., goethite, lepidocrocite, hematite, or magnetite) as electron acceptor. Fifty-eight out of 136 incubation conditions allowed the continued existence of microorganisms as confirmed by PCR amplification. High-throughput Illumina sequencing and clone library analysis based on 16S rRNA genes revealed that the enrichment cultures on each of the ferric <span class="hlt">iron</span> <span class="hlt">oxides</span> contained bacteria belonging to the Deltaproteobacteria (mainly Geobacteraceae), followed by Firmicutes and Chloroflexi, which also comprised most of the operational taxonomic units (OTUs) identified. Venn diagrams indicated that the core OTUs enriched with all of the <span class="hlt">iron</span> <span class="hlt">oxides</span> were dominant in the Geobacteraceae while each type of <span class="hlt">iron</span> <span class="hlt">oxides</span> supplemented selectively enriched specific OTUs in the other phylogenetic groups. Secondly, 38 enrichment cultures including novel microorganisms were transferred to soluble-<span class="hlt">iron</span>(III) containing media in order to stimulate the proliferation of the enriched <span class="hlt">iron</span> reducers. Through extinction dilution-culture and single colony isolation, six strains within the Deltaproteobacteria were finally obtained; five strains belonged to the genus Geobacter and one strain to Pelobacter. The 16S rRNA genes of these isolates were 94.8-98.1% identical in sequence to cultured relatives. All the isolates were able to grow on acetate and ferric <span class="hlt">iron</span> but their physiological characteristics differed considerably in</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25999927','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25999927"><span id="translatedtitle">Isolation of microorganisms involved in reduction of crystalline <span class="hlt">iron</span>(III) <span class="hlt">oxides</span> in natural environments.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hori, Tomoyuki; Aoyagi, Tomo; Itoh, Hideomi; Narihiro, Takashi; Oikawa, Azusa; Suzuki, Kiyofumi; Ogata, Atsushi; Friedrich, Michael W; Conrad, Ralf; Kamagata, Yoichi</p> <p>2015-01-01</p> <p>Reduction of crystalline Fe(III) <span class="hlt">oxides</span> is one of the most important electron sinks for organic compound <span class="hlt">oxidation</span> in natural environments. Yet the limited number of isolates makes it difficult to understand the physiology and ecological impact of the microorganisms involved. Here, two-stage cultivation was implemented to selectively enrich and isolate crystalline <span class="hlt">iron</span>(III) <span class="hlt">oxide</span> reducing microorganisms in soils and sediments. Firstly, <span class="hlt">iron</span> reducers were enriched and other untargeted eutrophs were depleted by 2-years successive culture on a crystalline ferric <span class="hlt">iron</span> <span class="hlt">oxide</span> (i.e., goethite, lepidocrocite, hematite, or magnetite) as electron acceptor. Fifty-eight out of 136 incubation conditions allowed the continued existence of microorganisms as confirmed by PCR amplification. High-throughput Illumina sequencing and clone library analysis based on 16S rRNA genes revealed that the enrichment cultures on each of the ferric <span class="hlt">iron</span> <span class="hlt">oxides</span> contained bacteria belonging to the Deltaproteobacteria (mainly Geobacteraceae), followed by Firmicutes and Chloroflexi, which also comprised most of the operational taxonomic units (OTUs) identified. Venn diagrams indicated that the core OTUs enriched with all of the <span class="hlt">iron</span> <span class="hlt">oxides</span> were dominant in the Geobacteraceae while each type of <span class="hlt">iron</span> <span class="hlt">oxides</span> supplemented selectively enriched specific OTUs in the other phylogenetic groups. Secondly, 38 enrichment cultures including novel microorganisms were transferred to soluble-<span class="hlt">iron</span>(III) containing media in order to stimulate the proliferation of the enriched <span class="hlt">iron</span> reducers. Through extinction dilution-culture and single colony isolation, six strains within the Deltaproteobacteria were finally obtained; five strains belonged to the genus Geobacter and one strain to Pelobacter. The 16S rRNA genes of these isolates were 94.8-98.1% identical in sequence to cultured relatives. All the isolates were able to grow on acetate and ferric <span class="hlt">iron</span> but their physiological characteristics differed considerably in</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.5916B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.5916B"><span id="translatedtitle">Pilot scale application of nanosized <span class="hlt">iron</span> <span class="hlt">oxides</span> as electron acceptors for bioremediation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bosch, Julian; Fritzsche, Andreas; Frank-Fahle, Beatrice; Lüders, Tilmann; Höss, Sebastian; Eisenmann, Heinrich; Held, Thomas; Totsche, Kai U.; Meckenstock, Rainer U.</p> <p>2014-05-01</p> <p>Microbial reduction of ferric <span class="hlt">iron</span> is a major biogeochemical process in groundwater aquifer ecosystems and often associated with the degradation of organic contaminants, as bacteria couple <span class="hlt">iron</span> reduction to the <span class="hlt">oxidation</span> reduced carbon like e.g. BTEX. Yet in general the low bioavailability of natural <span class="hlt">iron</span> <span class="hlt">oxides</span> limits microbial reduction rates. However, nanosized <span class="hlt">iron</span> <span class="hlt">oxides</span> have an unequally enhanced bioavailability and reactivity compared to their respective bulk, macro-sized, and more crystalline materials. At the same time, nanosized <span class="hlt">iron</span> <span class="hlt">oxides</span> can be produced in stable colloidal suspensions, permitting efficient injections into contaminated aquifers. We examined the reactivity of nanosized synthetic colloidal <span class="hlt">iron</span> <span class="hlt">oxides</span> in microbial <span class="hlt">iron</span> reduction. Application of colloidal nanoparticles led to a strong and sustainable enhancement of microbial reaction rates in batch experiments and sediment columns. Toluene <span class="hlt">oxidation</span> was increased five-fold as compared to bulk, non-colloidal ferrihydrite as electron acceptor. Furthermore, we developed a unique approach for custom-tailoring the subsurface mobility of these particles after being injected into a contaminant plume. In a field pilot application, we injected 18 m3 of an <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticle solution into a BTEX contaminated aquifer with a maximum excess pressure as low as 0.2 bar. The applied suspension showed a superior subsurface mobility, creating a reactive zone of 4 m height (corresponding to the height of the confined aquifer) and 6 m in diameter. Subsequent monitoring of BTEX, microbial BTEX degradation metabolites, ferrous <span class="hlt">iron</span> generation, stable isotopes fractionation, microbial populations, and methanogenesis demonstrated the strong impact of our approach. Mathematic processed X-ray diffractograms and FTIR spectra provided a semi-quantitatively estimate of the long-term fate of the <span class="hlt">iron</span> <span class="hlt">oxide</span> colloids in the aquifer. Potential environmental risks of the injection itself were monitored with</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5952439','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5952439"><span id="translatedtitle"><span class="hlt">Iron</span> sulfide <span class="hlt">oxidation</span> and the chemistry of acid generation</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sullivan, P.J.; Yelton, J.L. ); Reddy, K.J. )</p> <p>1988-06-01</p> <p>Acid mine drainage, produced from the <span class="hlt">oxidation</span> of <span class="hlt">iron</span> sulfides, often contains elevated levels of dissolved aluminum (Al), <span class="hlt">iron</span> (Fe), and sulfate (SO{sub 4}) and low pH. Understanding the interactions of these elements associated with acid mine drainage is necessary for proper solid waste management planning. Two eastern oil shales were leached using humidity cell methods. This study used a New Albany Shale (4.6% pyrite) and a Chattanooga Shale (1.5% pyrite) were used. The leachates from the humidity cells were filtered, and the filtrates were analyzed for total concentrations of cations and anions. After correcting for significant solution species and complexes, ion activities were calculated from total concentrations. The results show that the activities of Fe{sup 3+}, Fe{sup 2+}, Al{sup 3+}, and SO{sub 4}{sup 2{minus}} increased due to the <span class="hlt">oxidation</span> of pyrite. Furthermore, the <span class="hlt">oxidation</span> of pyrite resulted in a decreased pH and an increased pe + pH (redox-potential). The Fe{sup 3+} and Fe{sup 2+} activities appeared to be controlled by amorphous Fe(OH){sub 3} solid phase above a pH of 6.0 and below pe + pH 11.0. The Fe{sup 3+}, Fe{sup 2+}, and SO{sub 4}{sup 2{minus}} activities reached saturation with respect to FeOHSO{sub 4} solid phase between pH 3.0 and 6.0 and below pe + pH 11.0. Below a pH of 3.0 and above a pe + pH of 11.0, Fe{sup 2+}, Fe{sup 3+}, and SO{sub 4}{sup 2{minus}} activities are supported by FeSO{sub 4}{center dot}7H{sub 2}O solid phase. Above a pH of 6.0, the Al{sup 3+} activity showed an equilibrium with amorphous Al(OH){sub 3} solid phase. Below pH 6.0, Al{sup 3+} and SO{sub 4}{sup 2{minus}} activities are regulated by the AlOHSO{sub 4} solid phase, irrespective of pe + pH. The results of this study suggest that under <span class="hlt">oxidizing</span> conditions with low to high leaching potential, activities of Al and Fe can be predicted on the basis of secondary mineral formation over a wide range of pH and redox.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1073561','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1073561"><span id="translatedtitle">Exchange bias in Core-Shell <span class="hlt">Iron-Iron</span> <span class="hlt">Oxide</span> Nanoclusters</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kaur, Maninder; McCloy, John S.; Qiang, You</p> <p>2013-04-03</p> <p>An exchange bias study has been performed on core-shell <span class="hlt">iron-iron</span> <span class="hlt">oxide</span> (Fe-Fe3O4) nanoclusters (NCs) of size 11 nm and 14 nm carrying a different core to shell ratio. NCs show complicated behaviors due to competition between interfacial exchange and Zeeman energy in the presence of magnetic field during cooling. These behaviors are accompanied by the evolution of size- dependent cluster structures in the ferromagnetic-core/ferri- or antiferro-magnetic-shell. Smaller clusters have larger coercive field, exchange bias field, and vertical magnetization shift due to the greater contribution from frozen spins of shell/interfaces. These smaller clusters thus also show more dramatic changes with the training effect. Both sizes of clusters display an additional anomaly of the upper part of the hysteresis loop at 10 K under low cooling field (0.1 kOe). This anomaly decreases with number of loop cycles with same field, and disappear with large cooling field (> 0.1 kOe). It may be caused by the competition between the magnetization reversal and the magnetostatic interactions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4899443','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4899443"><span id="translatedtitle"><span class="hlt">Iron</span> <span class="hlt">Oxide</span> Nanoparticles as a Potential <span class="hlt">Iron</span> Fertilizer for Peanut (Arachis hypogaea)</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Rui, Mengmeng; Ma, Chuanxin; Hao, Yi; Guo, Jing; Rui, Yukui; Tang, Xinlian; Zhao, Qi; Fan, Xing; Zhang, Zetian; Hou, Tianqi; Zhu, Siyuan</p> <p>2016-01-01</p> <p>Nanomaterials are used in practically every aspect of modern life, including agriculture. The aim of this study was to evaluate the effectiveness of <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles (Fe2O3 NPs) as a fertilizer to replace traditional Fe fertilizers, which have various shortcomings. The effects of the Fe2O3 NPs and a chelated-Fe fertilizer (ethylenediaminetetraacetic acid-Fe; EDTA-Fe) fertilizer on the growth and development of peanut (Arachis hypogaea), a crop that is very sensitive to Fe deficiency, were studied in a pot experiment. The results showed that Fe2O3 NPs increased root length, plant height, biomass, and SPAD values of peanut plants. The Fe2O3 NPs promoted the growth of peanut by regulating phytohormone contents and antioxidant enzyme activity. The Fe contents in peanut plants with Fe2O3 NPs and EDTA-Fe treatments were higher than the control group. We used energy dispersive X-ray spectroscopy (EDS) to quantitatively analyze Fe in the soil. Peanut is usually cultivated in sandy soil, which is readily leached of fertilizers. However, the Fe2O3 NPs adsorbed onto sandy soil and improved the availability of Fe to the plants. Together, these results show that Fe2O3 NPs can replace traditional Fe fertilizers in the cultivation of peanut plants. To the best of our knowledge, this is the first research on the Fe2O3 NPs as the <span class="hlt">iron</span> fertilizer. PMID:27375665</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27375665','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27375665"><span id="translatedtitle"><span class="hlt">Iron</span> <span class="hlt">Oxide</span> Nanoparticles as a Potential <span class="hlt">Iron</span> Fertilizer for Peanut (Arachis hypogaea).</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Rui, Mengmeng; Ma, Chuanxin; Hao, Yi; Guo, Jing; Rui, Yukui; Tang, Xinlian; Zhao, Qi; Fan, Xing; Zhang, Zetian; Hou, Tianqi; Zhu, Siyuan</p> <p>2016-01-01</p> <p>Nanomaterials are used in practically every aspect of modern life, including agriculture. The aim of this study was to evaluate the effectiveness of <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles (Fe2O3 NPs) as a fertilizer to replace traditional Fe fertilizers, which have various shortcomings. The effects of the Fe2O3 NPs and a chelated-Fe fertilizer (ethylenediaminetetraacetic acid-Fe; EDTA-Fe) fertilizer on the growth and development of peanut (Arachis hypogaea), a crop that is very sensitive to Fe deficiency, were studied in a pot experiment. The results showed that Fe2O3 NPs increased root length, plant height, biomass, and SPAD values of peanut plants. The Fe2O3 NPs promoted the growth of peanut by regulating phytohormone contents and antioxidant enzyme activity. The Fe contents in peanut plants with Fe2O3 NPs and EDTA-Fe treatments were higher than the control group. We used energy dispersive X-ray spectroscopy (EDS) to quantitatively analyze Fe in the soil. Peanut is usually cultivated in sandy soil, which is readily leached of fertilizers. However, the Fe2O3 NPs adsorbed onto sandy soil and improved the availability of Fe to the plants. Together, these results show that Fe2O3 NPs can replace traditional Fe fertilizers in the cultivation of peanut plants. To the best of our knowledge, this is the first research on the Fe2O3 NPs as the <span class="hlt">iron</span> fertilizer.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27375665','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27375665"><span id="translatedtitle"><span class="hlt">Iron</span> <span class="hlt">Oxide</span> Nanoparticles as a Potential <span class="hlt">Iron</span> Fertilizer for Peanut (Arachis hypogaea).</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Rui, Mengmeng; Ma, Chuanxin; Hao, Yi; Guo, Jing; Rui, Yukui; Tang, Xinlian; Zhao, Qi; Fan, Xing; Zhang, Zetian; Hou, Tianqi; Zhu, Siyuan</p> <p>2016-01-01</p> <p>Nanomaterials are used in practically every aspect of modern life, including agriculture. The aim of this study was to evaluate the effectiveness of <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles (Fe2O3 NPs) as a fertilizer to replace traditional Fe fertilizers, which have various shortcomings. The effects of the Fe2O3 NPs and a chelated-Fe fertilizer (ethylenediaminetetraacetic acid-Fe; EDTA-Fe) fertilizer on the growth and development of peanut (Arachis hypogaea), a crop that is very sensitive to Fe deficiency, were studied in a pot experiment. The results showed that Fe2O3 NPs increased root length, plant height, biomass, and SPAD values of peanut plants. The Fe2O3 NPs promoted the growth of peanut by regulating phytohormone contents and antioxidant enzyme activity. The Fe contents in peanut plants with Fe2O3 NPs and EDTA-Fe treatments were higher than the control group. We used energy dispersive X-ray spectroscopy (EDS) to quantitatively analyze Fe in the soil. Peanut is usually cultivated in sandy soil, which is readily leached of fertilizers. However, the Fe2O3 NPs adsorbed onto sandy soil and improved the availability of Fe to the plants. Together, these results show that Fe2O3 NPs can replace traditional Fe fertilizers in the cultivation of peanut plants. To the best of our knowledge, this is the first research on the Fe2O3 NPs as the <span class="hlt">iron</span> fertilizer. PMID:27375665</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.V52B..02S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.V52B..02S"><span id="translatedtitle">A Holistic Model That Physicochemically Links <span class="hlt">Iron</span> <span class="hlt">Oxide</span> - Apatite and <span class="hlt">Iron</span> <span class="hlt">Oxide</span> - Copper - Gold Deposits to Magmas</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Simon, A. C.; Reich, M.; Knipping, J.; Bilenker, L.; Barra, F.; Deditius, A.; Lundstrom, C.; Bindeman, I. N.</p> <p>2015-12-01</p> <p><span class="hlt">Iron</span> <span class="hlt">oxide</span>-apatite (IOA) and <span class="hlt">iron</span> <span class="hlt">oxide</span>-copper-gold deposits (IOCG) are important sources of their namesake metals and increasingly for rare earth metals in apatite. Studies of natural systems document that IOA and IOCG deposits are often spatially and temporally related with one another and coeval magmatism. However, a genetic model that accounts for observations of natural systems remains elusive, with few observational data able to distinguish among working hypotheses that invoke meteoric fluid, magmatic-hydrothermal fluid, and immiscible melts. Here, we use Fe and O isotope data and high-resolution trace element (e.g., Ti, V, Mn, Al) data of individual magnetite grains from the world-class Los Colorados (LC) IOA deposit in the Chilean <span class="hlt">Iron</span> Belt to elucidate the origin of IOA and IOCG deposits. Values of d56Fe range from 0.08‰ to 0.26‰, which are within the global range of ~0.06‰ to 0.5‰ for magnetite formed at magmatic conditions. Values of δ18O for magnetite and actinolite are 2.04‰ and 6.08‰, respectively, consistent with magmatic values. Ti, V, Al, and Mn are enriched in magnetite cores and decrease systematically from core to rim. Plotting [Al + Mn] vs. [Ti + V] indicates that magnetite cores are consistent with magmatic and/or magmatic-hydrothermal (i.e., porphyry) magnetites. Decreasing Al, Mn, Ti, V is consistent with a cooling trend from porphyry to Kiruna to IOCG systems. The data from LC are consistent with the following new genetic model for IOA and IOCG systems: 1) magnetite cores crystallize from silicate melt; 2) these magnetite crystals are nucleation sites for aqueous fluid that exsolves and scavenges inter alia Fe, P, S, Cu, Au from silicate melt; 3) the magnetite-fluid suspension is less dense that the surrounding magma, allowing ascent; 4) as the suspension ascends, magnetite grows in equilibrium with the fluid and takes on a magmatic-hydrothermal character (i.e., lower Al, Mn, Ti, V); 5) during ascent, magnetite, apatite and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.B41H0155J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.B41H0155J"><span id="translatedtitle">Environmental Factors Affecting Ammonium <span class="hlt">Oxidation</span> Under <span class="hlt">Iron</span> Reducing Conditions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jaffe, P. R.; Huang, S.; Ruiz-Urigüen, M.</p> <p>2014-12-01</p> <p>Ammonium (NH4+) <span class="hlt">oxidation</span> coupled to <span class="hlt">iron</span> (Fe) reduction in the absence of oxygen and nitrate/nitrite (NO3-/NO2-) has been reported by several investigators and referred to as Feammox. Feammox is a biological reaction, where Fe(III) is the electron acceptor, which is reduced to Fe(II), and NH4+ is the electron donor, which is <span class="hlt">oxidized</span> to NO2-. Through a 180-day anaerobic incubation experiment, and using PCR-DGGE, 454-pyosequecing and qPCR analysis, we have shown that an Acidimicrobiaceae bacterium A6, a previously unreported species in the Acidimicrobiaceae family, might be either responsible or plays a key role in the Feammox process, We have enriched these Feammox bacteria (65.8% in terms of cell numbers) in a membrane reactor, and isolated the pure Acidimicrobiaceae bacterium A6 strain in an autotrophic medium. In samples collected and then incubated from a series of local wetland-, upland-, as well as storm-water detention pond-sediments, Feammox activity was only detected in acidic soil environments that contain Fe <span class="hlt">oxides</span>. Using primers we developed for this purpose, Acidimicrobiaceae bacterium A6 was detected in all incubations where Feammox was observed. Anaerobic incubations of Feammox enrichment cultures adjusted to different pH, revealed that the optimal pH for Feammox is 4 ~ 5, and the reaction does not proceed when pH > 7. Feammox was still proceeding at pH as low as 2. In Feammox culture amended with different Fe(III) sources, Feammox reaction proceeded only when Fe <span class="hlt">oxides</span> (ferrihydrite or goethite ) were supplied, whereas samples incubated with ferric chloride or ferric citrate showed no measurable NH4+ <span class="hlt">oxidation</span>. Furthermore, we have also determined from incubation experiments conducted with a temperature gradient (10 ~ 35℃), that the Feammox process was active when the temperature is above 15℃, and the optimal temperature is 20℃. Incubations of enrichment culture with 79% Feammox bacteria appeared to remove circa 8% more NH4+ at 20ºC than at</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22919479','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22919479"><span id="translatedtitle">Concurrent dual contrast for cellular magnetic resonance imaging using gadolinium <span class="hlt">oxide</span> and <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Loai, Yasir; Ganesh, Tameshwar; Cheng, Hai-Ling Margaret</p> <p>2012-01-01</p> <p>Rationale and Objectives. Concurrent visualization of differential targets in cellular and molecular imaging is valuable for resolving processes spatially and temporally, as in monitoring different cell subtypes. The purpose of this study was to demonstrate concurrent, dual (positive and negative) contrast visualization on magnetic resonance imaging (MRI) of two colocalized cell populations labeled with Gadolinium "Gd" <span class="hlt">oxide</span> and <span class="hlt">iron</span> "Fe" <span class="hlt">oxide</span> nanoparticles. Materials and Methods. Human aortic endothelial cells (EC) and smooth muscle cells (SMC) were labeled with various concentrations of Gd <span class="hlt">oxide</span> and Fe <span class="hlt">oxide</span>, respectively. MRI on single- or mixed-cell samples was performed at 7 tesla. Proper cell phenotype expressions, cell uptake of contrast agents, and the effect of labeling on cell viability and proliferation were also determined. Results. Both contrast agents were efficiently taken up by cells, with viability and proliferation largely unaffected. On MRI, the positive contrast associated with Gd <span class="hlt">oxide</span>-labeled EC and negative contrast associated with Fe <span class="hlt">oxide</span>-labeled SMC discriminated the presence of each cell type, whether it existed alone or colocalized in a mixed-cell sample. Conclusion. It is feasible to use Gd <span class="hlt">oxide</span> and Fe <span class="hlt">oxide</span> for dual contrast and concurrent discrimination of two colocalized cell populations on MRI at 7 tesla.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6099179','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6099179"><span id="translatedtitle">Ferrous <span class="hlt">iron</span> <span class="hlt">oxidation</span> by Thiobacillus ferrooxidans: inhibition with benzoic acid, sorbic acid and sodium lauryl sulfate</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Onysko, S.J.</p> <p>1984-07-01</p> <p>Acid mine drainage is formed by the weathering or <span class="hlt">oxidation</span> of pyritic material exposed during coal mining. The rate of pyritic material <span class="hlt">oxidation</span> can be greatly accelerated by certain acidophilic bacteria such as Thiobacillus ferrooxidans which catalyse the <span class="hlt">oxidation</span> of ferrous to ferric <span class="hlt">iron</span>. A number of organic compounds, under laboratory conditions, can apparently inhibit both the <span class="hlt">oxidation</span> of ferrous to ferric <span class="hlt">iron</span> by T. ferrooxidans and the weathering of pyritic material by mixed cultures of acid mine drainage micro-organisms. Sodium lauryl sulphate (SLS), an anionic surfactant has proved effective in this respect. Benzoic acid, sorbic acid and SLS at low concentrations, each effectively inhibited bacterial <span class="hlt">oxidation</span> of ferrous <span class="hlt">iron</span> in batch cultures of T. ferrooxidans. The rate of chemical <span class="hlt">oxidation</span> of ferrous <span class="hlt">iron</span> in low pH, sterile, batch reactors was not substantially affected at the tested concentrations of any of the compounds.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1996GeCoA..60.1531G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1996GeCoA..60.1531G"><span id="translatedtitle">Gold and <span class="hlt">iron</span> <span class="hlt">oxide</span> associations under supergene conditions: An experimental approach</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Greffié, Catherine; Benedetti, Marc F.; Parron, Claude; Amouric, Marc</p> <p>1996-05-01</p> <p>Abstract-The interaction of gold hydroxo-chloro complexes with <span class="hlt">iron</span> <span class="hlt">oxides</span> (ferrihydrites, goethites) during coprecipitation experiments is investigated. Chemical analyses of solids and solutions are coupled with a detailed characterization of the <span class="hlt">iron</span> <span class="hlt">oxides</span> with various methods, including X-ray diffraction, High Resolution Transmission Electron Microscopy (HRTEM), and Mössbauer spectroscopy. HCl solutions containing varying amounts of AuCl 4- and ferric nitrate were titrated to neutral or alkaline pH, resulting in the coprecipitation of gold and <span class="hlt">iron</span> <span class="hlt">oxide</span> phases (ferrihydrite or goethite). Reference titrations were performed in the absence of <span class="hlt">iron</span>. Most of the gold was removed from solution in the presence of <span class="hlt">iron</span> <span class="hlt">oxides</span> whereas gold remained dissolved in the reference samples. In association with <span class="hlt">iron</span> <span class="hlt">oxides</span> two forms of gold have been identified by HRTEM and 197Au Mössbauer spectroscopy: metallic gold as well as chloro and/or hydroxo combined gold. This combined gold is in a trivalent state as the primary product which means that a reduction process is not a necessary step for the adsorption of gold species on <span class="hlt">iron</span> <span class="hlt">oxides</span>. Metallic gold characterized in these products by means of HRTEM consists mainly of colloids ranging from 3-60 nm in diameter embedded in the ferrihydrite matrix, as isolated particles or as particles associated with goethite laths. The smallest metallic gold particles detected would be almost invisible to classical observation techniques used for solid phases. In our experiments, <span class="hlt">oxidation</span>-reduction reactions between Fe 2+ and Au 3+ are responsible for the presence of metallic gold observed on the <span class="hlt">iron</span> phases. Photochemical reactions may also take part in the reduction process. Colloidal gold and gold complexes could be associated to the <span class="hlt">iron</span> <span class="hlt">oxides</span> by strong electrostatic interactions. Our results suggest that poorly ordered <span class="hlt">iron</span> <span class="hlt">oxides</span> are highly efficient in trapping gold from solutions thanks to their high surface area, and favor gold</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/12785525','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/12785525"><span id="translatedtitle"><span class="hlt">Oxidation</span> of H2S by <span class="hlt">iron</span> <span class="hlt">oxides</span> in unsaturated conditions.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Cantrell, Kirk J; Yabusaki, Steven B; Engelhard, Mark H; Mitroshkov, Alexandre V; Thornton, Edward C</p> <p>2003-05-15</p> <p>Previous studies have demonstrated that gas-phase H2S can immobilize certain redox-sensitive contaminants (e.g., Cr, U, Tc) in vadose zone environments. A key issue for effective and efficient delivery of H2S in these environments is the reactivity of the gas with indigenous <span class="hlt">iron</span> <span class="hlt">oxides</span>. To elucidate the factors that control the transport of H2S in the vadose zone, laboratory column experiments were conducted to identify reaction mechanisms and measure rates of H2S <span class="hlt">oxidation</span> by <span class="hlt">iron</span> <span class="hlt">oxide</span>-coated sands using several carrier gas compositions (N2, air, and O2) and flow rates. Most experiments were conducted using ferrihydrite-coated sand. Additional studies were conducted with goethite- and hematite-coated sand and a natural sediment. Selective extractions were conducted at the end of each column experiment to determine the mass balance of the reaction products. XPS was used to confirm the presence of the reaction products. For column experiments in which ferrihydrite-coated sand was the substrate and N2 was the carrier gas, the major H2S <span class="hlt">oxidation</span> products were FeS and elemental sulfur (mostly S8(0), represented as S(0) for simplicity) at ratios that were consistent with the stoichiometry of the postulated reactions. When air or O2 were used as the carrier gas, S(0) became the dominant reaction product along with FeS2 and smaller amounts of FeS, sulfate, and thiosulfate. A mathematical model of reactive transport was used to test the hypothesis that S(0) forming on the <span class="hlt">iron</span> <span class="hlt">oxide</span> surfaces reduces access of H2S to the reactive surface. Several conceptual models were assessed in the context of the postulated reactions with the final model based on a linear surface poisoning model and fitted reaction rates. These results indicate that carrier gas selection is a critical consideration with significant tradeoffs for remediation objectives.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5453200','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5453200"><span id="translatedtitle">Observational evidence of crystalline <span class="hlt">iron</span> <span class="hlt">oxides</span> on Mars</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Bell, J.F. III; McCord, T.B.; Owensby, P.D. )</p> <p>1990-08-30</p> <p>Visible to near-IR (0.4-1.0 {mu}m) spectral reflectance observations of Mars during the 1988 opposition were performed at Mauna Kea Observatory using a circular variable filter spectrometer at a spectral resolution R = {lambda}/{Delta}{lambda} {approx} 80. On August 13 and 14 1988, UT, 41 regions 500-600 km in diameter were observed on Mars. The data have been reduced both to reflectance relative to solar analog (Mars/16 Cyg B) and to relative reflectance (spot/spot). The spectra show the strong near-UV reflectance dropoff characteristic of Mars as well as absorptions at 0.62-0.72 {mu}m and 0.81-0.94 {mu}m both seen here clearly for the first time. These absorption features are interpreted as Fe{sup 3+} electronic transition bands that indicate the presence of crystalline ferric <span class="hlt">oxide</span> or hydroxide minerals on the Martian surface. Comparison of these data with laboratory spectra obtained by other workers supports the conclusion that a single <span class="hlt">iron</span> <span class="hlt">oxide</span> phase, most likely hematite, could account for all of the observed spectral behavior of the Martian surface soils and airborne dust in the 0.4-1.0 {mu}m region. This possibility must be reconciled with data from other possible spectral analogs and other wavelength regions as well as geochemical and mineral stability considerations to arrive at a more complete understanding of the role of ferric minerals in Martian surface mineralogy and weathering.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015Nanot..26q5302S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015Nanot..26q5302S"><span id="translatedtitle">Biocompatible capped <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles for Vibrio cholerae detection</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sharma, Anshu; Baral, Dinesh; Rawat, Kamla; Solanki, Pratima R.; Bohidar, H. B.</p> <p>2015-05-01</p> <p>We report the studies relating to fabrication of an efficient immunosensor for Vibrio cholerae detection. Magnetite (<span class="hlt">iron</span> <span class="hlt">oxide</span> (Fe3O4)) nanoparticles (NPs) have been synthesized by the co-precipitation method and capped by citric acid (CA). These NPs were electrophoretically deposited onto indium-tin-<span class="hlt">oxide</span> (ITO)-coated glass substrate and used for immobilization of monoclonal antibodies against Vibrio cholerae (Ab) and bovine serum albumin (BSA) for Vibrio cholerae detection using an electrochemical technique. The structural and morphological studies of Fe3O4 and CA-Fe3O4/ITO were characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, and dynamic light scattering (DLS) techniques. The average crystalline size of Fe3O4, CA-Fe3O4 nanoparticles obtained were about 29 ± 1 nm and 37 ± 1 nm, respectively. The hydrodynamic radius of the nanoparticles was found to be 77.35 nm (Fe3O4) and 189.51 nm (CA-Fe3O4) by DLS measurement. The results of electrochemical response studies of the fabricated BSA/Ab/CA-Fe2O3/ITO immunosensor exhibits a good detection range of 12.5-500 ng mL-1 with a low detection limit of 0.32 ng mL-1, sensitivity 0.03 Ω/ng ml-1 cm-2, and reproducibility more than 11 times.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25850702','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25850702"><span id="translatedtitle">Biocompatible capped <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles for Vibrio cholerae detection.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sharma, Anshu; Baral, Dinesh; Rawat, Kamla; Solanki, Pratima R; Bohidar, H B</p> <p>2015-05-01</p> <p>We report the studies relating to fabrication of an efficient immunosensor for Vibrio cholerae detection. Magnetite (<span class="hlt">iron</span> <span class="hlt">oxide</span> (Fe(3)O(4))) nanoparticles (NPs) have been synthesized by the co-precipitation method and capped by citric acid (CA). These NPs were electrophoretically deposited onto indium-tin-<span class="hlt">oxide</span> (ITO)-coated glass substrate and used for immobilization of monoclonal antibodies against Vibrio cholerae (Ab) and bovine serum albumin (BSA) for Vibrio cholerae detection using an electrochemical technique. The structural and morphological studies of Fe(3)O(4) and CA-Fe(3)O(4)/ITO were characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, and dynamic light scattering (DLS) techniques. The average crystalline size of Fe(3)O(4), CA-Fe(3)O(4) nanoparticles obtained were about 29 ± 1 nm and 37 ± 1 nm, respectively. The hydrodynamic radius of the nanoparticles was found to be 77.35 nm (Fe(3)O(4)) and 189.51 nm (CA-Fe(3)O(4)) by DLS measurement. The results of electrochemical response studies of the fabricated BSA/Ab/CA-Fe(2)O(3)/ITO immunosensor exhibits a good detection range of 12.5-500 ng mL(-1) with a low detection limit of 0.32 ng mL(-1), sensitivity 0.03 Ω/ng ml(-1) cm(-2), and reproducibility more than 11 times.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17462704','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17462704"><span id="translatedtitle">Advanced <span class="hlt">oxidation</span> of natural organic matter using hydrogen peroxide and <span class="hlt">iron</span>-coated pumice particles.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kitis, M; Kaplan, S S</p> <p>2007-08-01</p> <p>The <span class="hlt">oxidative</span> removal of natural organic matter (NOM) from waters using hydrogen peroxide and <span class="hlt">iron</span>-coated pumice particles as heterogeneous catalysts was investigated. Two NOM sources were tested: humic acid solution and a natural source water. <span class="hlt">Iron</span> coated pumice removed about half of the dissolved organic carbon (DOC) concentration at a dose of 3000 mg l(-1) in 24 h by adsorption only. Original pumice and peroxide dosed together provided UV absorbance reductions as high as 49%, mainly due to the presence of metal <span class="hlt">oxides</span> including Al(2)O(3), Fe(2)O(3) and TiO(2) in the natural pumice, which are known to catalyze the decomposition of peroxide forming strong <span class="hlt">oxidants</span>. Coating the original pumice particles with <span class="hlt">iron</span> <span class="hlt">oxides</span> significantly enhanced the removal of NOM with peroxide. A strong linear correlation was found between <span class="hlt">iron</span> contents of coated pumices and UV absorbance reductions. Peroxide consumption also correlated with UV absorbance reduction. Control experiments proved the effective coating and the stability of <span class="hlt">iron</span> <span class="hlt">oxide</span> species bound on pumice surfaces. Results overall indicated that in addition to adsorptive removal of NOM by metal <span class="hlt">oxides</span> on pumice surfaces, surface reactions between <span class="hlt">iron</span> <span class="hlt">oxides</span> and peroxide result in the formation of strong <span class="hlt">oxidants</span>, probably like hydroxyl radicals, which further <span class="hlt">oxidize</span> both adsorbed NOM and remaining NOM in solution, similar to those in Fenton-like reactions.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_16 --> <div id="page_17" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="321"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27482521','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27482521"><span id="translatedtitle">Application of <span class="hlt">Iron</span> <span class="hlt">Oxide</span> as a pH-dependent Indicator for Improving the Nutritional Quality.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Meng, Xiangpeng; Ryu, Jina; Kim, Bumsik; Ko, Sanghoon</p> <p>2016-07-01</p> <p>Acid food indicators can be used as pH indicators for evaluating the quality and freshness of fermented products during the full course of distribution. <span class="hlt">Iron</span> <span class="hlt">oxide</span> particles are hardly suspended in water, but partially or completely agglomerated. The agglomeration degree of the <span class="hlt">iron</span> <span class="hlt">oxide</span> particles depends on the pH. The pH-dependent particle agglomeration or dispersion can be useful for monitoring the acidity of food. The zeta potential of <span class="hlt">iron</span> <span class="hlt">oxide</span> showed a decreasing trend as the pH increased from 2 to 8, while the point of zero charge (PZC) was observed around at pH 6.0-7.0. These results suggested that the size of the <span class="hlt">iron</span> <span class="hlt">oxide</span> particles was affected by the change in pH levels. As a result, the particle sizes of <span class="hlt">iron</span> <span class="hlt">oxide</span> were smaller at lower pH than at neutral pH. In addition, agglomeration of the <span class="hlt">iron</span> <span class="hlt">oxide</span> particles increased as the pH increased from 2 to 7. In the time-dependent aggregation test, the average particle size was 730.4 nm and 1,340.3 nm at pH 2 and 7, respectively. These properties of <span class="hlt">iron</span> <span class="hlt">oxide</span> particles can be used to develop an ideal acid indicator for food pH and to monitor food quality, besides a colorant or nutrient for nutrition enhancement and sensory promotion in food industry.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26319332','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26319332"><span id="translatedtitle">Synthesis and characterization of hybrid materials containing <span class="hlt">iron</span> <span class="hlt">oxide</span> for removal of sulfides from water.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Jacukowicz-Sobala, Irena; Wilk, Łukasz J; Drabent, Krzysztof; Kociołek-Balawejder, Elżbieta</p> <p>2015-12-15</p> <p>Hybrid materials containing <span class="hlt">iron</span> <span class="hlt">oxides</span> based on macroporous and gel-type sulfonic and carboxylic cation exchangers as supporting materials were obtained. Multiple factors, including the kind of functional groups, ion exchange capacity, and polymer matrix type (chemical constitution and porous structure), affected the amount of <span class="hlt">iron</span> <span class="hlt">oxides</span> introduced into their matrix (7.8-35.2% Fe). Products containing the highest <span class="hlt">iron</span> content were obtained using carboxylic cation exchangers, with their inorganic deposit being mostly a mixture of <span class="hlt">iron</span>(III) <span class="hlt">oxides</span>, including maghemite. Obtained hybrid polymers were used for removal of sulfides from anoxic aqueous solutions (50-200mgS(2-)/dm(3)). The research showed that the form (Na(+) or H(+)) of ionic groups of hybrid materials had a crucial impact on the sulfide removal process. Due to high <span class="hlt">iron</span> <span class="hlt">oxide</span> content (35% Fe), advantageous chemical constitution and porous structure, the highest removal efficiency (60mgS(2-)/g) was exhibited by a hybrid polymer obtained using a macroporous carboxylic cation exchanger as the host material. The process of sulfide removal was very complex and proceeded with heterogeneous <span class="hlt">oxidation</span>, <span class="hlt">iron</span>(III) <span class="hlt">oxide</span> reductive dissolution and formation of sulfide <span class="hlt">oxidation</span> and precipitation products such as <span class="hlt">iron</span>(II) sulfides, thiosulfates and polysulfides.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4967720','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4967720"><span id="translatedtitle">Application of <span class="hlt">Iron</span> <span class="hlt">Oxide</span> as a pH-dependent Indicator for Improving the Nutritional Quality</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p></p> <p>2016-01-01</p> <p>Acid food indicators can be used as pH indicators for evaluating the quality and freshness of fermented products during the full course of distribution. <span class="hlt">Iron</span> <span class="hlt">oxide</span> particles are hardly suspended in water, but partially or completely agglomerated. The agglomeration degree of the <span class="hlt">iron</span> <span class="hlt">oxide</span> particles depends on the pH. The pH-dependent particle agglomeration or dispersion can be useful for monitoring the acidity of food. The zeta potential of <span class="hlt">iron</span> <span class="hlt">oxide</span> showed a decreasing trend as the pH increased from 2 to 8, while the point of zero charge (PZC) was observed around at pH 6.0-7.0. These results suggested that the size of the <span class="hlt">iron</span> <span class="hlt">oxide</span> particles was affected by the change in pH levels. As a result, the particle sizes of <span class="hlt">iron</span> <span class="hlt">oxide</span> were smaller at lower pH than at neutral pH. In addition, agglomeration of the <span class="hlt">iron</span> <span class="hlt">oxide</span> particles increased as the pH increased from 2 to 7. In the time-dependent aggregation test, the average particle size was 730.4 nm and 1,340.3 nm at pH 2 and 7, respectively. These properties of <span class="hlt">iron</span> <span class="hlt">oxide</span> particles can be used to develop an ideal acid indicator for food pH and to monitor food quality, besides a colorant or nutrient for nutrition enhancement and sensory promotion in food industry. PMID:27482521</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27482521','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27482521"><span id="translatedtitle">Application of <span class="hlt">Iron</span> <span class="hlt">Oxide</span> as a pH-dependent Indicator for Improving the Nutritional Quality.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Meng, Xiangpeng; Ryu, Jina; Kim, Bumsik; Ko, Sanghoon</p> <p>2016-07-01</p> <p>Acid food indicators can be used as pH indicators for evaluating the quality and freshness of fermented products during the full course of distribution. <span class="hlt">Iron</span> <span class="hlt">oxide</span> particles are hardly suspended in water, but partially or completely agglomerated. The agglomeration degree of the <span class="hlt">iron</span> <span class="hlt">oxide</span> particles depends on the pH. The pH-dependent particle agglomeration or dispersion can be useful for monitoring the acidity of food. The zeta potential of <span class="hlt">iron</span> <span class="hlt">oxide</span> showed a decreasing trend as the pH increased from 2 to 8, while the point of zero charge (PZC) was observed around at pH 6.0-7.0. These results suggested that the size of the <span class="hlt">iron</span> <span class="hlt">oxide</span> particles was affected by the change in pH levels. As a result, the particle sizes of <span class="hlt">iron</span> <span class="hlt">oxide</span> were smaller at lower pH than at neutral pH. In addition, agglomeration of the <span class="hlt">iron</span> <span class="hlt">oxide</span> particles increased as the pH increased from 2 to 7. In the time-dependent aggregation test, the average particle size was 730.4 nm and 1,340.3 nm at pH 2 and 7, respectively. These properties of <span class="hlt">iron</span> <span class="hlt">oxide</span> particles can be used to develop an ideal acid indicator for food pH and to monitor food quality, besides a colorant or nutrient for nutrition enhancement and sensory promotion in food industry. PMID:27482521</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24036104','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24036104"><span id="translatedtitle">The complex interplay of <span class="hlt">iron</span> metabolism, reactive oxygen species, and reactive nitrogen species: insights into the potential of various <span class="hlt">iron</span> therapies to induce <span class="hlt">oxidative</span> and nitrosative stress.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Koskenkorva-Frank, Taija S; Weiss, Günter; Koppenol, Willem H; Burckhardt, Susanna</p> <p>2013-12-01</p> <p>Production of minute concentrations of superoxide (O2(*-)) and nitrogen monoxide (nitric <span class="hlt">oxide</span>, NO*) plays important roles in several aspects of cellular signaling and metabolic regulation. However, in an inflammatory environment, the concentrations of these radicals can drastically increase and the antioxidant defenses may become overwhelmed. Thus, biological damage may occur owing to redox imbalance-a condition called <span class="hlt">oxidative</span> and/or nitrosative stress. A complex interplay exists between <span class="hlt">iron</span> metabolism, O2(*-), hydrogen peroxide (H2O2), and NO*. <span class="hlt">Iron</span> is involved in both the formation and the scavenging of these species. <span class="hlt">Iron</span> deficiency (anemia) (ID(A)) is associated with <span class="hlt">oxidative</span> stress, but its role in the induction of nitrosative stress is largely unclear. Moreover, oral as well as intravenous (iv) <span class="hlt">iron</span> preparations used for the treatment of ID(A) may also induce <span class="hlt">oxidative</span> and/or nitrosative stress. Oral administration of ferrous salts may lead to high transferrin saturation levels and, thus, formation of non-transferrin-bound <span class="hlt">iron</span>, a potentially toxic form of <span class="hlt">iron</span> with a propensity to induce <span class="hlt">oxidative</span> stress. One of the factors that determine the likelihood of <span class="hlt">oxidative</span> and nitrosative stress induced upon administration of an iv <span class="hlt">iron</span> complex is the amount of labile (or weakly-bound) <span class="hlt">iron</span> present in the complex. Stable dextran-based <span class="hlt">iron</span> complexes used for iv therapy, although they contain only negligible amounts of labile <span class="hlt">iron</span>, can induce <span class="hlt">oxidative</span> and/or nitrosative stress through so far unknown mechanisms. In this review, after summarizing the main features of <span class="hlt">iron</span> metabolism and its complex interplay with O2(*-), H2O2, NO*, and other more reactive compounds derived from these species, the potential of various <span class="hlt">iron</span> therapies to induce <span class="hlt">oxidative</span> and nitrosative stress is discussed and possible underlying mechanisms are proposed. Understanding the mechanisms, by which various <span class="hlt">iron</span> formulations may induce <span class="hlt">oxidative</span> and nitrosative stress, will help us</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25871933','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25871933"><span id="translatedtitle">Dominance of sulfur-fueled <span class="hlt">iron</span> <span class="hlt">oxide</span> reduction in low-sulfate freshwater sediments.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hansel, Colleen M; Lentini, Chris J; Tang, Yuanzhi; Johnston, David T; Wankel, Scott D; Jardine, Philip M</p> <p>2015-11-01</p> <p>A central tenant in microbial biogeochemistry is that microbial metabolisms follow a predictable sequence of terminal electron acceptors based on the energetic yield for the reaction. It is thereby oftentimes assumed that microbial respiration of ferric <span class="hlt">iron</span> outcompetes sulfate in all but high-sulfate systems, and thus sulfide has little influence on freshwater or terrestrial <span class="hlt">iron</span> cycling. Observations of sulfate reduction in low-sulfate environments have been attributed to the presumed presence of highly crystalline <span class="hlt">iron</span> <span class="hlt">oxides</span> allowing sulfate reduction to be more energetically favored. Here we identified the <span class="hlt">iron</span>-reducing processes under low-sulfate conditions within columns containing freshwater sediments amended with structurally diverse <span class="hlt">iron</span> <span class="hlt">oxides</span> and fermentation products that fuel anaerobic respiration. We show that despite low sulfate concentrations and regardless of <span class="hlt">iron</span> <span class="hlt">oxide</span> substrate (ferrihydrite, Al-ferrihydrite, goethite, hematite), sulfidization was a dominant pathway in <span class="hlt">iron</span> reduction. This process was mediated by (re)cycling of sulfur upon reaction of sulfide and <span class="hlt">iron</span> <span class="hlt">oxides</span> to support continued sulfur-based respiration--a cryptic sulfur cycle involving generation and consumption of sulfur intermediates. Although canonical <span class="hlt">iron</span> respiration was not observed in the sediments amended with the more crystalline <span class="hlt">iron</span> <span class="hlt">oxides</span>, <span class="hlt">iron</span> respiration did become dominant in the presence of ferrihydrite once sulfate was consumed. Thus, despite more favorable energetics, ferrihydrite reduction did not precede sulfate reduction and instead an inverse redox zonation was observed. These findings indicate that sulfur (re)cycling is a dominant force in <span class="hlt">iron</span> cycling even in low-sulfate systems and in a manner difficult to predict using the classical thermodynamic ladder.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22285550','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22285550"><span id="translatedtitle"><span class="hlt">Iron</span> supplementation at high altitudes induces inflammation and <span class="hlt">oxidative</span> injury to lung tissues in rats</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Salama, Samir A.; Omar, Hany A.; Maghrabi, Ibrahim A.; AlSaeed, Mohammed S.; EL-Tarras, Adel E.</p> <p>2014-01-01</p> <p>Exposure to high altitudes is associated with hypoxia and increased vulnerability to <span class="hlt">oxidative</span> stress. Polycythemia (increased number of circulating erythrocytes) develops to compensate the high altitude associated hypoxia. <span class="hlt">Iron</span> supplementation is, thus, recommended to meet the demand for the physiological polycythemia. <span class="hlt">Iron</span> is a major player in redox reactions and may exacerbate the high altitudes-associated <span class="hlt">oxidative</span> stress. The aim of this study was to explore the potential <span class="hlt">iron</span>-induced <span class="hlt">oxidative</span> lung tissue injury in rats at high altitudes (6000 ft above the sea level). <span class="hlt">Iron</span> supplementation (2 mg elemental <span class="hlt">iron</span>/kg, once daily for 15 days) induced histopathological changes to lung tissues that include severe congestion, dilatation of the blood vessels, emphysema in the air alveoli, and peribronchial inflammatory cell infiltration. The levels of pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α), lipid peroxidation product and protein carbonyl content in lung tissues were significantly elevated. Moreover, the levels of reduced glutathione and total antioxidant capacity were significantly reduced. Co-administration of trolox, a water soluble vitamin E analog (25 mg/kg, once daily for the last 7 days of <span class="hlt">iron</span> supplementation), alleviated the lung histological impairments, significantly decreased the pro-inflammatory cytokines, and restored the <span class="hlt">oxidative</span> stress markers. Together, our findings indicate that <span class="hlt">iron</span> supplementation at high altitudes induces lung tissue injury in rats. This injury could be mediated through excessive production of reactive oxygen species and induction of inflammatory responses. The study highlights the tissue injury induced by <span class="hlt">iron</span> supplementation at high altitudes and suggests the co-administration of antioxidants such as trolox as protective measures. - Highlights: • <span class="hlt">Iron</span> supplementation at high altitudes induced lung histological changes in rats. • <span class="hlt">Iron</span> induced <span class="hlt">oxidative</span> stress in lung tissues of rats at high altitudes. • <span class="hlt">Iron</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1221470','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1221470"><span id="translatedtitle">Synthesis of phase-pure and monodisperse <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles by thermal decomposition</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hufschmid, Ryan D.; Arami, Hamed; Ferguson, R. Matthew; Gonzales, Marcela; Teeman, Eric M.; Brush, Lucien N.; Browning, Nigel D.; Krishnan, Kannan M.</p> <p>2015-06-03</p> <p>We present a comprehensive template for the design and synthesis of <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles with control over size, size distribution, phase, and resulting properties. Monodisperse superparamagnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles were synthesized by thermal decomposition of three different <span class="hlt">iron</span> containing precursors (<span class="hlt">iron</span> oleate, <span class="hlt">iron</span> pentacarbonyl, and <span class="hlt">iron</span> oxyhydroxide) in organic solvents under a variety of synthetic conditions. We compare the suitability of these three kinetically controlled synthesis protocols, which have in common the use of <span class="hlt">iron</span> oleate as a starting precursor or reaction intermediate, for producing nanoparticles with specific size and magnetic properties. Monodisperse particles were produced over a tunable range of sizes from approximately 2-30 nm. Reaction parameters such as precursor concentration, addition of surfactant, temperature, ramp rate, and time were adjusted to kinetically control size and size-distribution. In particular, large quantities of excess surfactant (up to 25:1 molar ratio) alter reaction kinetics and result in larger particles with uniform size; however, there is often a trade-off between large particles and a narrow size distribution. <span class="hlt">Iron</span> <span class="hlt">oxide</span> phase is also critical for establishing magnetic properties. As an example, we show the importance of obtaining the required <span class="hlt">iron</span> <span class="hlt">oxide</span> phase for application to Magnetic Particle Imaging (MPI), and describe how phase purity can be controlled.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24784347','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24784347"><span id="translatedtitle">Biosynthesis of stable <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles in aqueous extracts of Hordeum vulgare and Rumex acetosa plants.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Makarov, Valentin V; Makarova, Svetlana S; Love, Andrew J; Sinitsyna, Olga V; Dudnik, Anna O; Yaminsky, Igor V; Taliansky, Michael E; Kalinina, Natalia O</p> <p>2014-05-27</p> <p>We report the synthesis and characterization of amorphous <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles from <span class="hlt">iron</span> salts in aqueous extracts of monocotyledonous (Hordeum vulgare) and dicotyledonous (Rumex acetosa) plants. The nanoparticles were characterized by TEM, absorbance spectroscopy, SAED, EELS, XPS, and DLS methods and were shown to contain mainly <span class="hlt">iron</span> <span class="hlt">oxide</span> and <span class="hlt">iron</span> oxohydroxide. H. vulgare extracts produced amorphous <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles with diameters of up to 30 nm. These <span class="hlt">iron</span> nanoparticles are intrinsically unstable and prone to aggregation; however, we rendered them stable in the long term by addition of 40 mM citrate buffer pH 3.0. In contrast, amorphous <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles (diameters of 10-40 nm) produced using R. acetosa extracts are highly stable. The total protein content and antioxidant capacity are similar for both extracts, but pH values differ (H. vulgare pH 5.8 vs R. acetosa pH 3.7). We suggest that the presence of organic acids (such oxalic or citric acids) plays an important role in the stabilization of <span class="hlt">iron</span> nanoparticles, and that plants containing such constituents may be more efficacious for the green synthesis of <span class="hlt">iron</span> nanoparticles.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25822525','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25822525"><span id="translatedtitle">Secoisolariciresinol diglucoside abrogates <span class="hlt">oxidative</span> stress-induced damage in cardiac <span class="hlt">iron</span> overload condition.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Puukila, Stephanie; Bryan, Sean; Laakso, Anna; Abdel-Malak, Jessica; Gurney, Carli; Agostino, Adrian; Belló-Klein, Adriane; Prasad, Kailash; Khaper, Neelam</p> <p>2015-01-01</p> <p>Cardiac <span class="hlt">iron</span> overload is directly associated with cardiac dysfunction and can ultimately lead to heart failure. This study examined the effect of secoisolariciresinol diglucoside (SDG), a component of flaxseed, on <span class="hlt">iron</span> overload induced cardiac damage by evaluating <span class="hlt">oxidative</span> stress, inflammation and apoptosis in H9c2 cardiomyocytes. Cells were incubated with 50 μ5M <span class="hlt">iron</span> for 24 hours and/or a 24 hour pre-treatment of 500 μ M SDG. Cardiac <span class="hlt">iron</span> overload resulted in increased <span class="hlt">oxidative</span> stress and gene expression of the inflammatory mediators tumor necrosis factor-α, interleukin-10 and interferon γ, as well as matrix metalloproteinases-2 and -9. Increased apoptosis was evident by increased active caspase 3/7 activity and increased protein expression of Forkhead box O3a, caspase 3 and Bax. Cardiac <span class="hlt">iron</span> overload also resulted in increased protein expression of p70S6 Kinase 1 and decreased expression of AMP-activated protein kinase. Pre-treatment with SDG abrogated the <span class="hlt">iron</span>-induced increases in <span class="hlt">oxidative</span> stress, inflammation and apoptosis, as well as the increased p70S6 Kinase 1 and decreased AMP-activated protein kinase expression. The decrease in superoxide dismutase activity by <span class="hlt">iron</span> treatment was prevented by pre-treatment with SDG in the presence of <span class="hlt">iron</span>. Based on these findings we conclude that SDG was cytoprotective in an in vitro model of <span class="hlt">iron</span> overload induced redox-inflammatory damage, suggesting a novel potential role for SDG in cardiac <span class="hlt">iron</span> overload.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014Nanos...7...38W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014Nanos...7...38W"><span id="translatedtitle">Recent progress in magnetic <span class="hlt">iron</span> <span class="hlt">oxide</span>-semiconductor composite nanomaterials as promising photocatalysts</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wu, Wei; Changzhong Jiang, Affc; Roy, Vellaisamy A. L.</p> <p>2014-11-01</p> <p>Photocatalytic degradation of toxic organic pollutants is a challenging tasks in ecological and environmental protection. Recent research shows that the magnetic <span class="hlt">iron</span> <span class="hlt">oxide</span>-semiconductor composite photocatalytic system can effectively break through the bottleneck of single-component semiconductor <span class="hlt">oxides</span> with low activity under visible light and the challenging recycling of the photocatalyst from the final products. With high reactivity in visible light, magnetic <span class="hlt">iron</span> <span class="hlt">oxide</span>-semiconductors can be exploited as an important magnetic recovery photocatalyst (MRP) with a bright future. On this regard, various composite structures, the charge-transfer mechanism and outstanding properties of magnetic <span class="hlt">iron</span> <span class="hlt">oxide</span>-semiconductor composite nanomaterials are sketched. The latest synthesis methods and recent progress in the photocatalytic applications of magnetic <span class="hlt">iron</span> <span class="hlt">oxide</span>-semiconductor composite nanomaterials are reviewed. The problems and challenges still need to be resolved and development strategies are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23176453','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23176453"><span id="translatedtitle">Influence of Fe(2+)-catalysed <span class="hlt">iron</span> <span class="hlt">oxide</span> recrystallization on metal cycling.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Latta, Drew E; Gorski, Christopher A; Scherer, Michelle M</p> <p>2012-12-01</p> <p>Recent work has indicated that <span class="hlt">iron</span> (oxyhydr-)<span class="hlt">oxides</span> are capable of structurally incorporating and releasing metals and nutrients as a result of Fe2+-induced <span class="hlt">iron</span> <span class="hlt">oxide</span> recrystallization. In the present paper, we briefly review the current literature examining the mechanisms by which <span class="hlt">iron</span> <span class="hlt">oxides</span> recrystallize and summarize how recrystallization affects metal incorporation and release. We also provide new experimental evidence for the Fe2+-induced release of structural manganese from manganese-doped goethite. Currently, the exact mechanism(s) for Fe2+-induced recrystallization remain elusive, although they are likely to be both <span class="hlt">oxide</span>-and metal-dependent. We conclude by discussing some future research directions for Fe2+-catalysed <span class="hlt">iron</span> <span class="hlt">oxide</span> recrystallization.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25406760','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25406760"><span id="translatedtitle">Recent progress in magnetic <span class="hlt">iron</span> <span class="hlt">oxide</span>-semiconductor composite nanomaterials as promising photocatalysts.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wu, Wei; Changzhong Jiang; Roy, Vellaisamy A L</p> <p>2015-01-01</p> <p>Photocatalytic degradation of toxic organic pollutants is a challenging tasks in ecological and environmental protection. Recent research shows that the magnetic <span class="hlt">iron</span> <span class="hlt">oxide</span>-semiconductor composite photocatalytic system can effectively break through the bottleneck of single-component semiconductor <span class="hlt">oxides</span> with low activity under visible light and the challenging recycling of the photocatalyst from the final products. With high reactivity in visible light, magnetic <span class="hlt">iron</span> <span class="hlt">oxide</span>-semiconductors can be exploited as an important magnetic recovery photocatalyst (MRP) with a bright future. On this regard, various composite structures, the charge-transfer mechanism and outstanding properties of magnetic <span class="hlt">iron</span> <span class="hlt">oxide</span>-semiconductor composite nanomaterials are sketched. The latest synthesis methods and recent progress in the photocatalytic applications of magnetic <span class="hlt">iron</span> <span class="hlt">oxide</span>-semiconductor composite nanomaterials are reviewed. The problems and challenges still need to be resolved and development strategies are discussed. PMID:25406760</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ApSS..364...75T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ApSS..364...75T"><span id="translatedtitle">Gold catalysts supported on nanosized <span class="hlt">iron</span> <span class="hlt">oxide</span> for low-temperature <span class="hlt">oxidation</span> of carbon monoxide and formaldehyde</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tang, Zheng; Zhang, Weidong; Li, Yi; Huang, Zuming; Guo, Huishan; Wu, Feng; Li, Jinjun</p> <p>2016-02-01</p> <p>This study aimed to optimize synthesis of gold catalyst supported on nanosized <span class="hlt">iron</span> <span class="hlt">oxide</span> and to evaluate the activity in <span class="hlt">oxidation</span> of carbon monoxide and formaldehyde. Nanosized <span class="hlt">iron</span> <span class="hlt">oxide</span> was prepared from a colloidal dispersion of hydrous <span class="hlt">iron</span> <span class="hlt">oxide</span> through a dispersion-precipitation method. Gold was adsorbed onto nanosized <span class="hlt">iron</span> <span class="hlt">oxide</span> under self-generated basic conditions. Characterization results indicate that the <span class="hlt">iron</span> <span class="hlt">oxide</span> consisted of hematite/maghemite composite with primary particle sizes of 6-8 nm. Gold was highly dispersed on the surface of the support. The catalysts showed good activity in the <span class="hlt">oxidation</span> of airborne carbon monoxide and formaldehyde. The optimal pH for their synthesis was ∼7. The catalytic performance could be enhanced by extending the adsorption time of gold species on the support within 21 h. The optimized catalyst was capable of achieving complete <span class="hlt">oxidation</span> of 1% carbon monoxide at -20 °C and 33% conversion of 450 ppm formaldehyde at ambient temperature. The catalyst may be applicable to indoor air purification.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27217062','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27217062"><span id="translatedtitle"><span class="hlt">Iron</span>(II) Initiation of Lipid and Protein <span class="hlt">Oxidation</span> in Pork: The Role of Oxymyoglobin.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhou, Feibai; Jongberg, Sisse; Zhao, Mouming; Sun, Weizheng; Skibsted, Leif H</p> <p>2016-06-01</p> <p><span class="hlt">Iron</span>(II), added as FeSO4·7H2O, was found to increase the rate of oxygen depletion as detected electrochemically in a pork homogenate from Longissimus dorsi through an initial increase in metmyoglobin formation from oxymyoglobin and followed by formation of primary and secondary lipid <span class="hlt">oxidation</span> products and protein <span class="hlt">oxidation</span> as detected as thiol depletion in myofibrillar proteins. Without added <span class="hlt">iron</span>(II), under the same conditions at 37 °C, oxygen consumption corresponded solely to the slow oxymyoglobin autoxidation. Long-lived myofibrillar protein radicals as detected by ESR spectroscopy in the presence of <span class="hlt">iron</span>(II) were formed subsequently to oxymyoglobin <span class="hlt">oxidation</span>, and their level was increased by lipid <span class="hlt">oxidation</span> when oxygen was completely depleted. Similarly, the time profile for formation of lipid peroxide indicated that oxymyoglobin <span class="hlt">oxidation</span> initiates both protein <span class="hlt">oxidation</span> and lipid <span class="hlt">oxidation</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014AIPC.1621..600G&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014AIPC.1621..600G&link_type=ABSTRACT"><span id="translatedtitle">An evaluation of <span class="hlt">iron</span> <span class="hlt">oxide</span> nanofluids in enhanced oil recovery application</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Guan, Beh Hoe; Khalid, M. Hanafi M.; Matraji, Herman Hari; Chuan, Lee Kean; Soleimani, Hassan</p> <p>2014-10-01</p> <p>This paper evaluates the oil recover efficiency of <span class="hlt">Iron</span> <span class="hlt">Oxide</span> (Fe2O3) nanofluids in EOR. <span class="hlt">Iron</span> <span class="hlt">Oxide</span> nanoparticles were synthesized at two different temperatures via sol-gel method. TEM results show that the Fe2O3 prepared at 300°C and 600°C were ranged from 10-25nm and 30-90nm, respectively. Results showed that the nanofluid composed of <span class="hlt">Iron</span> <span class="hlt">Oxide</span> nanoparticles prepared at 300°C gives 10% increase in the oil recovery in comparison with Fe2O3 nanoparticles calcined at 600°C.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6306801','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/biblio/6306801"><span id="translatedtitle">Decaking of coal or oil shale during pyrolysis in the presence of <span class="hlt">iron</span> <span class="hlt">oxides</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Rashid Khan, M.</p> <p>1988-05-05</p> <p>A method for producing a fuel from the pyrolysis of coal or oil shale in the presence of <span class="hlt">iron</span> <span class="hlt">oxide</span> in an inert gas atmosphere is described. The method includes the steps of pulverizing feed coal or oil shale, pulverizing <span class="hlt">iron</span> <span class="hlt">oxide</span>, mixing the pulverized feed and <span class="hlt">iron</span> <span class="hlt">oxide</span>, and heating the mixture in a gas atmosphere which is substantially inert to the mixture so as to form a product fuel, which may be gaseous, liquid and/or solid. The method of the invention reduces the swelling of coals, such as bituminous coal and the like, which are otherwise known to swell during pyrolysis. 4 figs., 8 tabs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AIPC.1731m0011P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AIPC.1731m0011P"><span id="translatedtitle">Synthesis and magnetic study of carbon coated <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles by laser ablation in solution</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Prajapat, C. L.; Sharma, P.; Gonal, M. R.; Vatsa, R. K.; Singh, M. R.; Ravikumar, G.</p> <p>2016-05-01</p> <p>Magnetic <span class="hlt">Iron</span> <span class="hlt">oxides</span> nanoparticles (NPs) were prepared by Laser Ablation in Solution method. Formation and average size of <span class="hlt">iron</span> <span class="hlt">oxide</span> NPs (~8 nm) is confirmed by XRD pattern and magnetization studies. Detailed magnetic studies have been carried out using SQUID magnetometer. The saturation magnetization for the <span class="hlt">iron</span> <span class="hlt">oxide</span> NPs was found to be 60.07 emu/g. Below the blocking temperature of 150 K the hysteresis loop shows ferromagnetic nature, whereas it shows superparamagnetic behavior at 300 K, for the synthesized NPs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/867208','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/867208"><span id="translatedtitle">Decaking of coal or oil shale during pyrolysis in the presence of <span class="hlt">iron</span> <span class="hlt">oxides</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Khan, M. Rashid</p> <p>1989-01-01</p> <p>A method for producing a fuel from the pyrolysis of coal or oil shale in the presence of <span class="hlt">iron</span> <span class="hlt">oxide</span> in an inert gas atmosphere. The method includes the steps of pulverizing feed coal or oil shale, pulverizing <span class="hlt">iron</span> <span class="hlt">oxide</span>, mixing the pulverized feed and <span class="hlt">iron</span> <span class="hlt">oxide</span>, and heating the mixture in a gas atmosphere which is substantially inert to the mixture so as to form a product fuel, which may be gaseous, liquid and/or solid. The method of the invention reduces the swelling of coals, such as bituminous coal and the like, which are otherwise known to swell during pyrolysis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..1711520M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..1711520M"><span id="translatedtitle">Early diagenetic quartz formation at a deep <span class="hlt">iron</span> <span class="hlt">oxidation</span> front in the Eastern Equatorial Pacific</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Meister, Patrick; Chapligin, Bernhard; Picard, Aude; Meyer, Hanno; Fischer, Cornelius; Rettenwander, Daniel; Amthauer, Georg; Vogt, Christoph; Aiello, Ivano</p> <p>2015-04-01</p> <p>The mechanisms of early diagenetic quartz formation under low-temperature conditions are still poorly understood. We studied lithified cherts consisting of microcrystalline quartz recovered from ODP Site 1226 in the Eastern Equatorial Pacific. The cherts occur near the base of a 420-m-thick Miocene-Holocene sequence within unlithified nannofossil and diatom ooze. Palaeo-temperatures reconstructed from δ18O values in the cherts are near to present porewater temperatures and a sharp depletion in dissolved silica occurs around 385 mbsf indicating that silica precipitation is still ongoing. Also a deep <span class="hlt">iron</span> <span class="hlt">oxidation</span> front occurs at the same depth, which is caused by upward diffusing nitrate from an oxic seawater aquifer in the underlying basaltic crust. Sequential <span class="hlt">iron</span> extraction and analysis of the X-ray absorption near-edge structure (XANES) revealed that <span class="hlt">iron</span> in the cherts predominantly occurs as illite and amorphous <span class="hlt">iron</span> <span class="hlt">oxide</span>, whereas <span class="hlt">iron</span> in the nannofossil and diatom ooze occurs mainly as smectites. Mössbauer spectroscopy confirmed that the illite <span class="hlt">iron</span> in the cherts is largely <span class="hlt">oxidized</span>. A possible mechanisms that may be operative is quartz precipitation initiated by adsorption of silica to freshly precipitated <span class="hlt">iron</span> <span class="hlt">oxides</span>. The decrease in porewater silica concentration below opal-A and opal-CT saturation then allows for the precipitation of the thermodynamically more stable phase: quartz. We suggest that the formation of early-diagenetic chert at <span class="hlt">iron</span> <span class="hlt">oxidation</span> fronts is an important process in suboxic zones of silica-rich sediments. The largest <span class="hlt">iron</span> <span class="hlt">oxidation</span> front ever occurred during the great <span class="hlt">oxidation</span> event ca. 2.5 Ga ago, when large amounts of <span class="hlt">iron</span> and chert beds were deposited.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_17 --> <div id="page_18" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="341"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4928111','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4928111"><span id="translatedtitle"><span class="hlt">Iron</span> overload by Superparamagnetic <span class="hlt">Iron</span> <span class="hlt">Oxide</span> Nanoparticles is a High Risk Factor in Cirrhosis by a Systems Toxicology Assessment</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Wei, Yushuang; Zhao, Mengzhu; Yang, Fang; Mao, Yang; Xie, Hang; Zhou, Qibing</p> <p>2016-01-01</p> <p>Superparamagnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles (SPIONs) as a contrast agent have been widely used in magnetic resonance imaging for tumor diagnosis and theranostics. However, there has been safety concern of SPIONs with cirrhosis related to excess <span class="hlt">iron</span>-induced <span class="hlt">oxidative</span> stress. In this study, the impact of <span class="hlt">iron</span> overload by SPIONs was assessed on a mouse cirrhosis model. A single dose of SPION injection at 0.5 or 5 mg Fe/kg in the cirrhosis group induced a septic shock response at 24 h with elevated serum levels of liver and kidney function markers and extended impacts over 14 days including high levels of serum cholesterols and persistent low serum <span class="hlt">iron</span> level. In contrast, full restoration of liver functions was found in the normal group with the same dosages over time. Analysis with PCR array of the toxicity pathways revealed the high dose of SPIONs induced significant expression changes of a distinct subset of genes in the cirrhosis liver. All these results suggested that excess <span class="hlt">iron</span> of the high dose of SPIONs might be a risk factor for cirrhosis because of the marked impacts of elevated lipid metabolism, disruption of <span class="hlt">iron</span> homeostasis and possibly, aggravated loss of liver functions. PMID:27357559</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27357559','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27357559"><span id="translatedtitle"><span class="hlt">Iron</span> overload by Superparamagnetic <span class="hlt">Iron</span> <span class="hlt">Oxide</span> Nanoparticles is a High Risk Factor in Cirrhosis by a Systems Toxicology Assessment.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wei, Yushuang; Zhao, Mengzhu; Yang, Fang; Mao, Yang; Xie, Hang; Zhou, Qibing</p> <p>2016-01-01</p> <p>Superparamagnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles (SPIONs) as a contrast agent have been widely used in magnetic resonance imaging for tumor diagnosis and theranostics. However, there has been safety concern of SPIONs with cirrhosis related to excess <span class="hlt">iron</span>-induced <span class="hlt">oxidative</span> stress. In this study, the impact of <span class="hlt">iron</span> overload by SPIONs was assessed on a mouse cirrhosis model. A single dose of SPION injection at 0.5 or 5 mg Fe/kg in the cirrhosis group induced a septic shock response at 24 h with elevated serum levels of liver and kidney function markers and extended impacts over 14 days including high levels of serum cholesterols and persistent low serum <span class="hlt">iron</span> level. In contrast, full restoration of liver functions was found in the normal group with the same dosages over time. Analysis with PCR array of the toxicity pathways revealed the high dose of SPIONs induced significant expression changes of a distinct subset of genes in the cirrhosis liver. All these results suggested that excess <span class="hlt">iron</span> of the high dose of SPIONs might be a risk factor for cirrhosis because of the marked impacts of elevated lipid metabolism, disruption of <span class="hlt">iron</span> homeostasis and possibly, aggravated loss of liver functions. PMID:27357559</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/19782750','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/19782750"><span id="translatedtitle"><span class="hlt">Oxidation</span> of elemental sulfur, tetrathionate and ferrous <span class="hlt">iron</span> by the psychrotolerant Acidithiobacillus strain SS3.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kupka, Daniel; Liljeqvist, Maria; Nurmi, Pauliina; Puhakka, Jaakko A; Tuovinen, Olli H; Dopson, Mark</p> <p>2009-12-01</p> <p>Mesophilic <span class="hlt">iron</span> and sulfur-<span class="hlt">oxidizing</span> acidophiles are readily found in acid mine drainage sites and bioleaching operations, but relatively little is known about their activities at suboptimal temperatures and in cold environments. The purpose of this work was to characterize the <span class="hlt">oxidation</span> of elemental sulfur (S(0)), tetrathionate (S4O6(2-)) and ferrous <span class="hlt">iron</span> (Fe2+) by the psychrotolerant Acidithiobacillus strain SS3. The rates of elemental sulfur and tetrathionate <span class="hlt">oxidation</span> had temperature optima of 20 degrees and 25 degrees C, respectively, determined using a temperature gradient incubator that involved narrow (1.1 degrees C) incremental increases from 5 degrees to 30 degrees C. Activation energies calculated from the Arrhenius plots were 61 and 89 kJ mol(-1) for tetrathionate and 110 kJ mol(-1) for S(0) <span class="hlt">oxidation</span>. The <span class="hlt">oxidation</span> of elemental sulfur produced sulfuric acid at 5 degrees C and decreased the pH to approximately 1. The low pH inhibited further <span class="hlt">oxidation</span> of the substrate. In media with both S(0) and Fe2+, <span class="hlt">oxidation</span> of elemental sulfur did not commence until all available ferrous <span class="hlt">iron</span> was <span class="hlt">oxidized</span>. These data on sequential <span class="hlt">oxidation</span> of the two substrates are in keeping with upregulation and downregulation of several proteins previously noted in the literature. Ferric <span class="hlt">iron</span> was reduced to Fe2+ in parallel with elemental sulfur <span class="hlt">oxidation</span>, indicating the presence of a sulfur:ferric <span class="hlt">iron</span> reductase system in this bacterium. PMID:19782750</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70026818','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70026818"><span id="translatedtitle">Rare earth element partitioning between hydrous ferric <span class="hlt">oxides</span> and acid mine water during <span class="hlt">iron</span> <span class="hlt">oxidation</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Verplanck, P.L.; Nordstrom, D.K.; Taylor, H.E.; Kimball, B.A.</p> <p>2004-01-01</p> <p>Ferrous <span class="hlt">iron</span> rapidly <span class="hlt">oxidizes</span> to Fe (III) and precipitates as hydrous Fe (III) <span class="hlt">oxides</span> 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 <span class="hlt">oxidation</span> 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 <span class="hlt">oxidize</span> in the laboratory at ambient conditions to determine the partitioning of REEs during Fe <span class="hlt">oxidation</span> and precipitation. Results from field experiments document that even with substantial Fe <span class="hlt">oxidation</span>, 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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70027546','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70027546"><span id="translatedtitle">Hawaiian submarine manganese-<span class="hlt">iron</span> <span class="hlt">oxide</span> crusts - A dating tool?</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Moore, J.G.; Clague, D.A.</p> <p>2004-01-01</p> <p>Black manganese-<span class="hlt">iron</span> <span class="hlt">oxide</span> crusts form on most exposed rock on the ocean floor. Such crusts are well developed on the steep lava slopes of the Hawaiian Ridge and have been sampled during dredging and submersible dives. The crusts also occur on fragments detached from bedrock by mass wasting, on submerged coral reefs, and on poorly lithified sedimentary rocks. The thickness of the crusts was measured on samples collected since 1965 on the Hawaiian Ridge from 140 dive or dredge localities. Fifty-nine (42%) of the sites were collected in 2001 by remotely operated vehicles (ROVs). The thinner crusts on many samples apparently result from post-depositional breakage, landsliding, and intermittent burial of outcrops by sediment. The maximum crust thickness was selected from each dredge or dive site to best represent crusts on the original rock surface at that site. The measurements show an irregular progressive thickening of the crusts toward the northwest-i.e., progressive thickening toward the older volcanic features with increasing distance from the Hawaiian hotspot. Comparison of the maximum crust thickness with radiometric ages of related subaerial features supports previous studies that indicate a crust-growth rate of about 2.5 mm/m.y. The thickness information not only allows a comparison of the relative exposure ages of two or more features offshore from different volcanoes, but also provides specific age estimates of volcanic and landslide deposits. The data indicate that some of the landslide blocks within the south Kona landslide are the oldest exposed rock on Mauna Loa, Kilauea, or Loihi volcanoes. Crusts on the floors of submarine canyons off Kohala and East Molokai volcanoes indicate that these canyons are no longer serving as channelways for downslope, sediment-laden currents. Mahukona volcano was approximately synchronous with Hilo Ridge, both being younger than Hana Ridge. The Nuuanu landslide is considerably older than the Wailau landslide. The Waianae</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011PhDT........28X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011PhDT........28X"><span id="translatedtitle">Performance Optimization of Metallic <span class="hlt">Iron</span> and <span class="hlt">Iron</span> <span class="hlt">Oxide</span> Nanomaterials for Treatment of Impaired Water Supplies</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xie, Yang</p> <p></p> <p><span class="hlt">Iron</span> nanomaterials including nanoscale zero valent <span class="hlt">iron</span> (NZVI), NZVI-based bimetallic reductants (e.g., Pd/NZVI) and naturally occurring nanoscale <span class="hlt">iron</span> mineral phases represent promising treatment tools for impaired water supplies. However, questions pertaining to fundamental and practical aspects of their reactivity may limit their performance during applications. For NZVI treatment of pollutant source zones, a major hurdle is its limited reactive lifetime. In Chapter 2, we report the longevity of NZVI towards 1,1,1,2-tetrachloroethane (1,1,1,2-TeCA) and hexavalent chromium [Cr(VI)] in oxygen-free systems with various anionic co-solutes (e.g., Cl-, SO4 2-, ClO4-, HCO3 -, NO3-). Trends in longevity provide evidence that surface-associated Fe(II) species are responsible for Cr(VI) reduction, whereas 1,1,1,2-TeCA reduction depends on the accessibility of Fe(0) at the NZVI particle surface. In Chapter 3, we show that dithionite, previously utilized for in situ redox manipulation, can restore the reducing capacity of passivated NZVI treatment systems. Air <span class="hlt">oxidation</span> of NZVI at pH ≥ 8 quickly exhausted reactivity despite a significant fraction of Fe(0) persisting in the particle core. Reduction of this passive layer by low dithionite concentrations restored suspension reactivity to levels of unaged NZVI, with multiple dithionite additions further improving pollutant removal. In Chapter 4, measurements of solvent kinetic isotope effects reveals that optimal Pd/NZVI reactivity results from accumulation of atomic hydrogen, which only occurs in NZVI-based systems due to their higher rates of corrosion. However, atomic hydrogen formation only occurs in aged Pd/NZVI suspensions for ˜2 weeks, after which any reactivity enhancement likely results from galvanic corrosion of Fe(0). Finally, the activity of hybrid nanostructures consisting of multi-walled carbon nanotubes decorated with of hematite nanoparticles (alphaFe 2O3/MWCNT) is explored in Chapter 5. Sorption of Cu</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3604861','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3604861"><span id="translatedtitle">Ligand-Enhanced Abiotic <span class="hlt">Iron</span> <span class="hlt">Oxidation</span> and the Effects of Chemical versus Biological <span class="hlt">Iron</span> Cycling in Anoxic Environments</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p></p> <p>2013-01-01</p> <p>This study introduces a newly isolated, genetically tractable bacterium (Pseudogulbenkiania sp. strain MAI-1) and explores the extent to which its nitrate-dependent <span class="hlt">iron-oxidation</span> activity is directly biologically catalyzed. Specifically, we focused on the role of <span class="hlt">iron</span> chelating ligands in promoting chemical <span class="hlt">oxidation</span> of Fe(II) by nitrite under anoxic conditions. Strong organic ligands such as nitrilotriacetate and citrate can substantially enhance chemical <span class="hlt">oxidation</span> of Fe(II) by nitrite at circumneutral pH. We show that strain MAI-1 exhibits unambiguous biological Fe(II) <span class="hlt">oxidation</span> despite a significant contribution (∼30–35%) from ligand-enhanced chemical <span class="hlt">oxidation</span>. Our work with the model denitrifying strain Paracoccus denitrificans further shows that ligand-enhanced chemical <span class="hlt">oxidation</span> of Fe(II) by microbially produced nitrite can be an important general side effect of biological denitrification. Our assessment of reaction rates derived from literature reports of anaerobic Fe(II) <span class="hlt">oxidation</span>, both chemical and biological, highlights the potential competition and likely co-occurrence of chemical Fe(II) <span class="hlt">oxidation</span> (mediated by microbial production of nitrite) and truly biological Fe(II) <span class="hlt">oxidation</span>. PMID:23402562</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014ApWS....4..175D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014ApWS....4..175D"><span id="translatedtitle">Removal of <span class="hlt">iron</span> and arsenic (III) from drinking water using <span class="hlt">iron</span> <span class="hlt">oxide</span>-coated sand and limestone</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Devi, Rashmi R.; Umlong, Iohborlang M.; Das, Bodhaditya; Borah, Kusum; Thakur, Ashim J.; Raul, Prasanta K.; Banerjee, Saumen; Singh, Lokendra</p> <p>2014-06-01</p> <p>A method for removal of <span class="hlt">iron</span> and arsenic (III) from contaminated water using <span class="hlt">iron</span> <span class="hlt">oxide</span>-coated sand and limestone has been developed for drinking water. For the intended use, sand was coated with ferric chloride and used as filtering media. Limestone was added onto the coated sand and the effect of limestone addition on removal efficiency of <span class="hlt">iron</span> and arsenic was monitored. Both batch and column experiments were conducted to investigate the efficiency of coated sand and limestone as filtering media. Maximum removal of <span class="hlt">iron</span> (99.8 %) was obtained with coated sand at a dose of 5 g/100 ml and by adding 0.2 g/100 ml of limestone at pH 7.3. Arsenic (III) removal efficiency increased with the increased dose of coated sand and was best removed at pH 7.12. The maximum adsorption capacity for arsenic (III) obtained from Langmuir model was found to be 0.075 mg/g and the kinetics data followed pseudo-first order better than pseudo-second order. Energy dispersive X-ray analysis and FT-IR study proved the removal of <span class="hlt">iron</span> and arsenic. Column experiment showed removal of <span class="hlt">iron</span> and arsenic (III) to <0.3 mg/l and 10 μg/l, respectively, from an initial concentration of 20 mg/l (<span class="hlt">iron</span>) and 200 μg/l (arsenic).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=190856&keyword=iron+AND+oxide&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=78944962&CFTOKEN=59245413','EPA-EIMS'); return false;" href="http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=190856&keyword=iron+AND+oxide&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=78944962&CFTOKEN=59245413"><span id="translatedtitle">Soluble <span class="hlt">Iron</span> in Alveolar Macrophages Modulates <span class="hlt">Iron</span> <span class="hlt">Oxide</span> Particle-Induced Inflammatory Response via Prostaglandin E2 Synthesis</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>Ambient particulate matter (PM)-associated metals have been shown to play an important role in cardiopulmonary health outcomes. To study the modulation of inflammation by PM-associated soluble metal, we investigated intracellular solubility of radiolabelled <span class="hlt">iron</span> <span class="hlt">oxide</span> (<SUP>59</S...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1041909','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1041909"><span id="translatedtitle">Sulfur Versus <span class="hlt">Iron</span> <span class="hlt">Oxidation</span> in an <span class="hlt">Iron</span>-Thiolate Model Complex</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>A McDonald; M Bukowski; E Farquhar; T Jackson; K Koehntop; M Seo; R De Hont; A Stubna; J Halfen; E Munck</p> <p>2011-12-31</p> <p>In the absence of base, the reaction of [Fe{sup II}(TMCS)]PF{sub 6} (1, TMCS = 1-(2-mercaptoethyl)-4,8,11-trimethyl-1,4,8,11-tetraazacyclotetradecane) with peracid in methanol at -20 C did not yield the oxoiron(IV) complex (2, [Fe{sup IV}(O)(TMCS)]PF{sub 6}), as previously observed in the presence of strong base (KO{sup t}Bu). Instead, the addition of 1 equiv of peracid resulted in 50% consumption of 1. The addition of a second equivalent of peracid resulted in the complete consumption of 1 and the formation of a new species 3, as monitored by UV-vis, ESI-MS, and Moessbauer spectroscopies. ESI-MS showed 3 to be formulated as [Fe{sup II}(TMCS) + 2O]{sup +}, while EXAFS analysis suggested that 3 was an O-bound <span class="hlt">iron</span>(II)-sulfinate complex (Fe-O = 1.95 {angstrom}, Fe-S = 3.26 {angstrom}). The addition of a third equivalent of peracid resulted in the formation of yet another compound, 4, which showed electronic absorption properties typical of an oxoiron(IV) species. Moessbauer spectroscopy confirmed 4 to be a novel <span class="hlt">iron</span>(IV) compound, different from 2, and EXAFS (Fe{double_bond}O = 1.64 {angstrom}) and resonance Raman ({nu}{sub Fe{double_bond}O} = 831 cm{sup -1}) showed that indeed an oxoiron(IV) unit had been generated in 4. Furthermore, both infrared and Raman spectroscopy gave indications that 4 contains a metal-bound sulfinate moiety ({nu}{sub s}(SO{sub 2}) {approx} 1000 cm{sup -1}, {nu}{sub as}(SO{sub 2}) {approx} 1150 cm{sup -1}). Investigations into the reactivity of 1 and 2 toward H{sup +} and oxygen atom transfer reagents have led to a mechanism for sulfur <span class="hlt">oxidation</span> in which 2 could form even in the absence of base but is rapidly protonated to yield an oxoiron(IV) species with an uncoordinated thiol moiety that acts as both <span class="hlt">oxidant</span> and substrate in the conversion of 2 to 3.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3353163','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3353163"><span id="translatedtitle">Biomedical properties and preparation of <span class="hlt">iron</span> <span class="hlt">oxide</span>-dextran nanostructures by MAPLE technique</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p></p> <p>2012-01-01</p> <p>Background In this work the chemical structure of dextran-<span class="hlt">iron</span> <span class="hlt">oxide</span> thin films was reported. The films were obtained by MAPLE technique from composite targets containing 10 wt. % dextran with 1 and 5 wt.% <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles (IONPs). The IONPs were synthesized by co-precipitation method. A KrF* excimer laser source (λ = 248 nm, τFWHM≅25 ns, ν = 10 Hz) was used for the growth of the hybrid, <span class="hlt">iron</span> <span class="hlt">oxide</span> NPs-dextran thin films. Results Dextran coated <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles thin films were indexed into the spinel cubic lattice with a lattice parameter of 8.36 Å. The particle sized calculated was estimated at around 7.7 nm. The XPS shows that the binding energy of the Fe 2p3/2 of two thin films of dextran coated <span class="hlt">iron</span> <span class="hlt">oxide</span> is consistent with Fe3+ <span class="hlt">oxides</span>. The atomic percentage of the C, O and Fe are 66.71, 32.76 and 0.53 for the films deposited from composite targets containing 1 wt.% maghemite and 64.36, 33.92 and 1.72 respectively for the films deposited from composite targets containing 5 wt.% maghemite. In the case of cells cultivated on dextran coated 5% maghemite γ-Fe2O3, the number of cells and the level of F-actin were lower compared to the other two types of thin films and control. Conclusions The dextran-<span class="hlt">iron</span> <span class="hlt">oxide</span> continuous thin films obtained by MAPLE technique from composite targets containing 10 wt.% dextran as well as 1 and 5 wt.% <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles synthesized by co-precipitation method presented granular surface morphology. Our data proved a good viability of Hep G2 cells grown on dextran coated maghemite thin films. Also, no changes in cells morphology were noticed under phase contrast microscopy. The data strongly suggest the potential use of <span class="hlt">iron</span> <span class="hlt">oxide</span>-dextran nanocomposites as a potential marker for biomedical applications. PMID:22410001</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/1939058','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/1939058"><span id="translatedtitle"><span class="hlt">Iron</span> <span class="hlt">oxidation</span> chemistry in ferritin. Increasing Fe/O2 stoichiometry during core formation.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Xu, B; Chasteen, N D</p> <p>1991-10-25</p> <p>The origin of previously observed variations in stoichiometry of <span class="hlt">iron</span> <span class="hlt">oxidation</span> during the <span class="hlt">oxidative</span> deposition of <span class="hlt">iron</span> in ferritin has been poorly understood. Knowledge of the stoichiometry of Fe(II) <span class="hlt">oxidation</span> by O2 is essential to establishing the mechanism of <span class="hlt">iron</span> core formation. In the present work, the amount of Fe(II) <span class="hlt">oxidized</span> was measured by Mössbauer spectrometry and the O2 consumed by mass spectrometry. The number of protons produced in the reaction was measured by "pH stat" titration and hydrogen peroxide production by the effect of the enzyme catalase on the measured stoichiometry. For protein samples containing low levels of <span class="hlt">iron</span> (24 Fe(II)/protein) the stoichiometry was found to be 1.95 +/- 0.18 Fe(II)/O2 with H2O2 being a product, viz. Equation 1. 2Fe2+ + O2 + 4H2O----2FeOOH + H2O2 + 4H+ (1) EPR spin trapping experiments showed no evidence of superoxide radical formation. The stoichiometry markedly increased with additional <span class="hlt">iron</span> (240-960 Fe/protein), to a value of 4 Fe(II)/O2 as in Equation 2. 4Fe2+ + O2 + 6H2O----4FeOOH + 8H+ (2) As the <span class="hlt">iron</span> core is progressively laid down, the mechanism of <span class="hlt">iron</span> <span class="hlt">oxidation</span> changes from a protein dominated process with H2O2 being the primary product of O2 reduction to a mineral surface dominated process where H2O is the primary product. These results emphasize the importance of the apoferritin shell in facilitating <span class="hlt">iron</span> <span class="hlt">oxidation</span> in the early stage of <span class="hlt">iron</span> deposition prior to significant development of the polynuclear <span class="hlt">iron</span> core.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24287261','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24287261"><span id="translatedtitle">Carboxymethyl cellulose coating decreases toxicity and <span class="hlt">oxidizing</span> capacity of nanoscale zerovalent <span class="hlt">iron</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhou, Lei; Thanh, Thao Le; Gong, Jianyu; Kim, Jae-Hwan; Kim, Eun-Ju; Chang, Yoon-Seok</p> <p>2014-06-01</p> <p>Nanoscale zerovalent <span class="hlt">iron</span> (NZVI) with modified surface via coating with organic stabilizers has been documented with enhanced colloidal stability and dispersity. Therefore, the expanded application potential and accompanying intrinsic exposure of such nanoparticle can be anticipated. In our study, carboxymethyl cellulose (CMC)-stabilized NZVI (CNZVI) exerted minimized <span class="hlt">oxidative</span> stress response and slower disruption of cell membrane integrity, resulting in mitigated cytotoxicity towards bacteria Agrobacterium sp. PH-08 as compared with the uncoated counterpart. The corrosive <span class="hlt">oxidation</span> of both nanoparticles in oxygenic water provided a better understanding of coating effect. The decreased <span class="hlt">oxidative</span> degradation of probe 4-chlorophenol with CNZVI than NZVI implicated a weaker <span class="hlt">oxidizing</span> capacity, which might overweight massive adhesion-mediated redox damage and explain the different exposure outcome. However, enhanced evolution of <span class="hlt">iron</span> <span class="hlt">oxide</span> as well as the promoted production of hydrogen peroxide adversely demonstrated CMC-coating facilitated <span class="hlt">iron</span> corrosion by oxygen, suggesting CMC was most likely to act as a radical scavenger and compete with organics or bacteria for <span class="hlt">oxidants</span>. Moreover, XRD, XPS and TEM results showed that the spherical NZVI was <span class="hlt">oxidized</span> to form needle-shaped <span class="hlt">iron</span> <span class="hlt">oxide</span>-hydroxide (γFeOOH) with no detectable <span class="hlt">oxidative</span> stress for PH-08, alleviating worries regarding exotoxicological impact of <span class="hlt">iron</span> nanotechnology.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006GeCoA..70.1710T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006GeCoA..70.1710T"><span id="translatedtitle"><span class="hlt">Iron-oxide</span> crystallinity increases during soil redox oscillations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Thompson, Aaron; Chadwick, Oliver A.; Rancourt, Denis G.; Chorover, Jon</p> <p>2006-04-01</p> <p>An Inceptisol A-horizon from Hawaii was subjected to a series of reduction-<span class="hlt">oxidation</span> cycles—14 d cycle length over a 56 d duration—across the "soil-Fe" [Fe(OH) 3.Fe 2+(aq), log Ko = 15.74] equilibrium in triplicate redox-stat reactors. Each reducing event simulated the flush of organic C and diminished O 2 that accompanies a rainfall-induced leaching of bioavailable reductants from the forest floor into mineral soil. The soil contained considerable amounts of short-range ordered (SRO) minerals (e.g., nano-goethite and allophane) and organic matter (11% org-C). Room temperature and cryogenic 57Fe Mössbauer spectroscopy showed that the <span class="hlt">iron</span>-bearing minerals were dominated by nano- to micro-scale goethite, and that ferrihydrite was not present. Over the four full cycles, fluctuations in Eh (from 200 to 700 mV) and pFe 2+ (from 2.5 to 5.5) were inversely correlated with those of pH (5.5 to 4). Here, we focus on the solubility dynamics of the framework elements (Si, Fe, Ti, and Al) that constitute 35% of the oxygen-free soil dry mass. Intra-cycle oscillations in dissolved (<3 kDa) metals peaked during the reduction half-cycles. Similar intra-cycle oscillations were observed in the HCl and acid ammonium oxalate (AAO) extractable pools. The cumulative response of soil solids during multiple redox oscillations included: (1) a decrease in most HCl and AAO extractable metals and (2) a transformation of SRO Fe (as nano-goethite) to micro-crystalline goethite and micro-crystalline hematite. This may be the first direct demonstration that Fe <span class="hlt">oxide</span> crystallinity increases during redox oscillations—an a priori unexpected result.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26444653','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26444653"><span id="translatedtitle">Freezing-Enhanced Dissolution of <span class="hlt">Iron</span> <span class="hlt">Oxides</span>: Effects of Inorganic Acid Anions.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Jeong, Daun; Kim, Kitae; Min, Dae Wi; Choi, Wonyong</p> <p>2015-11-01</p> <p>Dissolution of <span class="hlt">iron</span> from mineral dust particles greatly depends upon the type and amount of copresent inorganic anions. In this study, we investigated the roles of sulfate, chloride, nitrate, and perchlorate on the dissolution of maghemite and lepidocrocite in ice under both dark and UV irradiation and compared the results with those of their aqueous counterparts. After 96 h of reaction, the total dissolved <span class="hlt">iron</span> in ice (pH 3 before freezing) was higher than that in the aqueous phase (pH 3) by 6-28 times and 10-20 times under dark and UV irradiation, respectively. Sulfuric acid was the most efficient in producing labile <span class="hlt">iron</span> under dark condition, whereas hydrochloric acid induced the most dissolution of the total and ferrous <span class="hlt">iron</span> in the presence of light. This ice-induced dissolution result was also confirmed with Arizona Test Dust (AZTD). In the freeze-thaw cycling test, the <span class="hlt">iron</span> <span class="hlt">oxide</span> samples containing chloride, nitrate, or perchlorate showed a similar extent of total dissolved <span class="hlt">iron</span> after each cycling while the sulfate-containing sample rapidly lost its dissolution activity with repeating the cycle. This unique phenomenon observed in ice might be related to the freeze concentration of protons, <span class="hlt">iron</span> <span class="hlt">oxides</span>, and inorganic anions in the liquid-like ice grain boundary region. These results suggest that the ice-enhanced dissolution of <span class="hlt">iron</span> <span class="hlt">oxides</span> can be a potential source of bioavailable <span class="hlt">iron</span>, and the acid anions critically influence this process.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26444653','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26444653"><span id="translatedtitle">Freezing-Enhanced Dissolution of <span class="hlt">Iron</span> <span class="hlt">Oxides</span>: Effects of Inorganic Acid Anions.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Jeong, Daun; Kim, Kitae; Min, Dae Wi; Choi, Wonyong</p> <p>2015-11-01</p> <p>Dissolution of <span class="hlt">iron</span> from mineral dust particles greatly depends upon the type and amount of copresent inorganic anions. In this study, we investigated the roles of sulfate, chloride, nitrate, and perchlorate on the dissolution of maghemite and lepidocrocite in ice under both dark and UV irradiation and compared the results with those of their aqueous counterparts. After 96 h of reaction, the total dissolved <span class="hlt">iron</span> in ice (pH 3 before freezing) was higher than that in the aqueous phase (pH 3) by 6-28 times and 10-20 times under dark and UV irradiation, respectively. Sulfuric acid was the most efficient in producing labile <span class="hlt">iron</span> under dark condition, whereas hydrochloric acid induced the most dissolution of the total and ferrous <span class="hlt">iron</span> in the presence of light. This ice-induced dissolution result was also confirmed with Arizona Test Dust (AZTD). In the freeze-thaw cycling test, the <span class="hlt">iron</span> <span class="hlt">oxide</span> samples containing chloride, nitrate, or perchlorate showed a similar extent of total dissolved <span class="hlt">iron</span> after each cycling while the sulfate-containing sample rapidly lost its dissolution activity with repeating the cycle. This unique phenomenon observed in ice might be related to the freeze concentration of protons, <span class="hlt">iron</span> <span class="hlt">oxides</span>, and inorganic anions in the liquid-like ice grain boundary region. These results suggest that the ice-enhanced dissolution of <span class="hlt">iron</span> <span class="hlt">oxides</span> can be a potential source of bioavailable <span class="hlt">iron</span>, and the acid anions critically influence this process. PMID:26444653</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=135691&keyword=free+AND+radicals&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=78953049&CFTOKEN=37142070','EPA-EIMS'); return false;" href="http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=135691&keyword=free+AND+radicals&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=78953049&CFTOKEN=37142070"><span id="translatedtitle"><span class="hlt">OXIDANT</span> GENERATION PROMOTES <span class="hlt">IRON</span> SEQUESTRATION IN BEAS-2B CELLS EXPOSED TO ASBESTOS</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>Lung injury following asbestos exposure is associated with an <span class="hlt">oxidative</span> stress that is catalyzed by <span class="hlt">iron</span> in the fiber matrix, complexed to the surface, or both. We tested the hypothesis that the cellular response to asbestos includes the transport and sequestration of this <span class="hlt">iron</span> ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=166843&keyword=jaspers&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=78785161&CFTOKEN=48026429','EPA-EIMS'); return false;" href="http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=166843&keyword=jaspers&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=78785161&CFTOKEN=48026429"><span id="translatedtitle">*<span class="hlt">OXIDANT</span> GENERATION PROMOTES <span class="hlt">IRON</span> SEQUESTRATION IN BEAS-2B CELLS EXPOSED TO ASBESTOS</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>Lung injury after asbestos exposure is associated with an <span class="hlt">oxidative</span> stress that is catalyzed by <span class="hlt">iron</span> in the fiber matrix, complexed to the surface, or both. We tested the hypothesis that the cellular response to asbestos includes the transport and sequestration of this <span class="hlt">iron</span> throu...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013JAP...113l4701O&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013JAP...113l4701O&link_type=ABSTRACT"><span id="translatedtitle">Magnetic resonance imaging of microvessels using <span class="hlt">iron-oxide</span> nanoparticles</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Olamaei, N.; Cheriet, F.; Martel, S.</p> <p>2013-03-01</p> <p>The visualization of microstructures including blood vessels with an inner overall cross-sectional area below approximately 200 μm remains beyond the capabilities of current clinical imaging modalities. But with magnetic resonance (MR) imaging, magnetic entities cause susceptibility artifacts in the images by disrupting the homogeneous magnetic field in a much larger scale than their actual size. As validated in this paper through simulation and in-vitro experiments, these artifacts can serve as a source of contrast, enabling microvessels with an inner diameter below the spatial resolution of any medical imaging modalities to be visualized using a clinical MR scanner. For such experiments, micron-sized agglomerations of <span class="hlt">iron-oxide</span> (Fe3O4) nanoparticles were injected in microchannels with internal diameters of 200 and 50 μm equivalent to a narrower artery or a larger arteriole, and down to a smaller arteriole, respectively. The results show the feasibility of the proposed method for micro-particle detection and the visualization of microvessels using a 1.5 T clinical MR scanner. It was confirmed that the method is reproducible and accurate at the sub-pixel level.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JMMM..407..101L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JMMM..407..101L"><span id="translatedtitle">Magnetic hyperthermia in phosphate coated <span class="hlt">iron</span> <span class="hlt">oxide</span> nanofluids</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lahiri, B. B.; Muthukumaran, T.; Philip, John</p> <p>2016-06-01</p> <p>We study the magnetic field induced hyperthermia in water based phosphate coated Fe3O4 nanofluids, synthesized by a co-precipitation method using ferrous and ferric salt solutions, ammonia and orthophosphoric acid. The specific absorption rate (SAR) values were measured at a fixed frequency of 126 kHz and at extremely low field amplitudes. The SAR values were determined from the initial rate of temperature rise curves under non-adiabatic conditions. It was observed that the SAR initially increases with sample concentration, attains a maximum at an optimum concentration and beyond which SAR decreases. The decrease in SAR values beyond the optimum concentration was attributed to the enhancement of dipolar interaction and agglomeration of the particles. The system independent intrinsic loss power (ILP) values, obtained by normalizing the SAR values with respect to field amplitude and frequency, were found to vary between 158-125 nHm2 kg-1, which were the highest benchmark values reported in the biologically safe experimental limit of 1.03-0.92×108 Am-1 s-1. The very high value of ILP observed in the bio-compatible phosphate coated <span class="hlt">iron</span> <span class="hlt">oxide</span> nanofluids may find practical applications for these nanoparticles in tumor targeted hyperthermia treatment.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_18 --> <div id="page_19" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="361"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004JVST...22..419C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004JVST...22..419C"><span id="translatedtitle">Fabrication of <span class="hlt">iron</span> (III) <span class="hlt">oxide</span> doped polystyrene shells</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cai, Pei-Jun; Tang, Yong-Jian; Zhang, Lin; Du, Kai; Feng, Chang-Gen</p> <p>2004-03-01</p> <p>A type of <span class="hlt">iron</span> (III) <span class="hlt">oxide</span> doped plastic shell used for inertial confinement fusion experiments has been fabricated by emulsion techniques. Three different phases of solution (W1, O, and W2) are used for the fabrication process. The W1 phase is a 1 wt % of sodium lauryl sulfate in water. This W1 phase solution is mixed with a 3 wt % Fe2O3-polystyrene (PS) solution in benzene-dichloroethane (O phase) while stirring. The resulting emulsion (W1/O) is poured into a 3 wt % aqueous polyvinyl alcohol solution (W2 phase) while stirring. The resulting emulsion (W1/O/W2) is then heated to evaporate benzene and dichloroethane, and thus a solid Fe2O3-PS shell is formed. The diameter and wall thickness of the shells range from 150 to 500 μm and 5 to 15 μm, respectively. The average surface roughness of the shells is 40 nm, similar to that of the usual PS shells. .</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4167583','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4167583"><span id="translatedtitle">Superparamagnetic <span class="hlt">Iron</span> <span class="hlt">Oxide</span> Nanoparticle-Based Delivery Systems for Biotherapeutics</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Mok, Hyejung; Zhang, Miqin</p> <p>2014-01-01</p> <p>Introduction Superparamagnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticle (SPION)-based carrier systems have many advantages over other nanoparticle-based systems. They are biocompatible, biodegradable, facilely tunable, and superparamagnetic and thus controllable by an external magnetic field. These attributes enable their broad biomedical applications. In particular, magnetically-driven carriers are drawing considerable interest as an emerging therapeutic delivery system because of their superior delivery efficiency. Area covered This article reviews the recent advances in use of SPION-based carrier systems to improve the delivery efficiency and target specificity of biotherapeutics. We examine various formulations of SPION-based delivery systems, including SPION micelles, clusters, hydrogels, liposomes, and micro/nanospheres, as well as their specific applications in delivery of biotherapeutics. Expert opinion Recently, biotherapeutics including therapeutic cells, proteins and genes have been studied as alternative treatments to various diseases. Despite the advantages of high target specificity and low adverse effects, clinical translation of biotherapeutics has been hindered by the poor stability and low delivery efficiency compared to chemical drugs. Accordingly, biotherapeutic delivery systems that can overcome these limitations are actively pursued. SPION-based materials can be ideal candidates for developing such delivery systems because of their excellent biocompatibility and superparamagnetism that enables long-term accumulation/retention at target sites by utilization of a suitable magnet. In addition, synthesis technologies for production of finely-tuned, homogeneous SPIONs have been well developed, which may promise their rapid clinical translation. PMID:23199200</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009JAP...105gB504P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009JAP...105gB504P"><span id="translatedtitle">Synthesis and magnetic properties of gold coated <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pal, Susmita; Morales, Marienette; Mukherjee, Pritish; Srikanth, Hariharan</p> <p>2009-04-01</p> <p>We report on synthesis, structural, and magnetic properties of chemically synthesized <span class="hlt">iron</span> <span class="hlt">oxide</span> (Fe3O4) and Fe3O4@Au core-shell nanoparticles. Structural characterization was done using x-ray diffraction and transmission electron microscopy, and the magnetite phase of the core (˜6nm) and fcc Au shell (thickness of ˜1nm) were confirmed. Magnetization (M) versus temperature (T) data at H =200Oe for zero-field-cooled and field-cooled modes exhibited a superparamagnetic blocking temperature TB˜35K (40K) for parent (core-shell) system. Enhanced coercivity (Hc˜200Oe) at 5K along with nonsaturating M-H loops observed for Fe3O4@Au nanoparticles indicate the possible role of spin disorder at the Au -Fe3O4 interface and weak exchange coupling between surface and core spins. Analysis of ac susceptibility (χ' and χ″) data shows that the interparticle interaction is reduced upon Au coating and the relaxation mechanism follows the Vogel-Fulcher law.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26540051','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26540051"><span id="translatedtitle">Genotoxicity of Superparamagnetic <span class="hlt">Iron</span> <span class="hlt">Oxide</span> Nanoparticles in Granulosa Cells.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Pöttler, Marina; Staicu, Andreas; Zaloga, Jan; Unterweger, Harald; Weigel, Bianca; Schreiber, Eveline; Hofmann, Simone; Wiest, Irmi; Jeschke, Udo; Alexiou, Christoph; Janko, Christina</p> <p>2015-01-01</p> <p>Nanoparticles that are aimed at targeting cancer cells, but sparing healthy tissue provide an attractive platform of implementation for hyperthermia or as carriers of chemotherapeutics. According to the literature, diverse effects of nanoparticles relating to mammalian reproductive tissue are described. To address the impact of nanoparticles on cyto- and genotoxicity concerning the reproductive system, we examined the effect of superparamagnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles (SPIONs) on granulosa cells, which are very important for ovarian function and female fertility. Human granulosa cells (HLG-5) were treated with SPIONs, either coated with lauric acid (SEONLA) only, or additionally with a protein corona of bovine serum albumin (BSA; SEON(LA-BSA)), or with dextran (SEON(DEX)). Both micronuclei testing and the detection of γH2A.X revealed no genotoxic effects of SEON(LA-BSA), SEON(DEX) or SEON(LA). Thus, it was demonstrated that different coatings of SPIONs improve biocompatibility, especially in terms of genotoxicity towards cells of the reproductive system. PMID:26540051</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5006844','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5006844"><span id="translatedtitle">Superparamagnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles regulate smooth muscle cell phenotype</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Angelopoulos, Ioannis; Southern, Paul; Pankhurst, Quentin A.</p> <p>2016-01-01</p> <p>Abstract Superparamagnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles (SPION) are used for an increasing range of biomedical applications, from imaging to mechanical actuation of cells and tissue. The aim of this study was to investigate the loading of smooth muscle cells (SMC) with SPION and to explore what effect this has on the phenotype of the cells. Adherent human SMC were loaded with ∼17 pg of unconjugated, negatively charged, 50 nm SPION. Clusters of the internalized SPION particles were held in discrete cytoplasmic vesicles. Internalized SPION did not cause any change in cell morphology, proliferation, metabolic activity, or staining pattern of actin and calponin, two of the muscle contractile proteins involved in force generation. However, internalized SPION inhibited the increased gene expression of actin and calponin normally observed when cells are incubated under differentiation conditions. The observed change in the control of gene expression of muscle contractile apparatus by SPION has not previously been described. This finding could offer novel approaches for regulating the phenotype of SMC and warrants further investigation. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2412–2419, 2016. PMID:27176658</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013MMTB..tmp..227D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013MMTB..tmp..227D"><span id="translatedtitle">Hydrogen Reduction of Zinc and <span class="hlt">Iron</span> <span class="hlt">Oxides</span> Containing Mixtures</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>de Siqueira, Rogério Navarro C.; de Albuquerque Brocchi, Eduardo; de Oliveira, Pamela Fernandes; Motta, Marcelo Senna</p> <p>2013-10-01</p> <p>Zinc is a metal of significant technological importance and its production from secondary sources has motivated the development of alternative processes, such as the chemical treatment of electrical arc furnace (EAF) dust. Currently, the extraction of zinc from the mentioned residue using a carbon-containing reducing agent is in the process of being established commercially and technically. In the current study, the possibility of reducing zinc from an EAF dust sample through a H2 constant flux in a horizontal oven is studied. The reduction of a synthetic <span class="hlt">oxide</span> mixture of analogous composition is also investigated. The results indicated that the reduction process is thermodynamically viable for temperatures higher than 1123 K (850 °C), and all zinc metal produced is transferred to the gas stream, enabling its complete separation from <span class="hlt">iron</span>. The same reaction in the presence of zinc crystals was considered for synthesizing FeZn alloys. However, for the experimental conditions employed, although ZnO reduction was indeed thermodynamically hindered because of the presence of zinc crystals (the metal's partial pressure was enhanced), the zinc metal's escape within the gaseous phase could not be effectively avoided.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JMMM..379..226L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JMMM..379..226L"><span id="translatedtitle">Solvothermal synthesis and characterization of monodisperse superparamagnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, Shichuan; Zhang, Tonglai; Tang, Runze; Qiu, Hao; Wang, Caiqin; Zhou, Zunning</p> <p>2015-04-01</p> <p>A series of magnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticle clusters with different structure guide agents were synthesized by a modified solvothermal method and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), thermogravimetric analyses (TG), a vibrating sample magnetometer (VSM) and Fourier transform infrared spectroscopy (FTIR). It is found that the superparamagnetic nanoparticles guided by NaCit (sodium citrate) have high saturation magnetization (Ms) of 69.641 emu/g and low retentivity (Mr) of 0.8 emu/g. Guiding to form superparamagnetic clusters with size range of 80-110 nm, the adherent small-molecule citrate groups on the surface prevent the prefabricated ferrite crystals growing further. In contrast, the primary small crystal guided and stabilized by the PVP long-chain molecules assemble freely to larger ones and stop growing in size range of 100-150 nm, which has saturation magnetization (Ms) of 97.979 emu/g and retentivity (Mr) of 46.323 emu/g. The relevant formation mechanisms of the two types of samples are proposed at the end. The superparamagnetic ferrite clusters guided by sodium citrate are expected to be used for movement controlling of passive interference particles to avoid aggregation and the sample guided by PVP will be a candidate of nanometer wave absorbing material.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26554870','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26554870"><span id="translatedtitle">Cell Labeling and Targeting with Superparamagnetic <span class="hlt">Iron</span> <span class="hlt">Oxide</span> Nanoparticles.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Tefft, Brandon J; Uthamaraj, Susheil; Harburn, J Jonathan; Klabusay, Martin; Dragomir-Daescu, Dan; Sandhu, Gurpreet S</p> <p>2015-10-19</p> <p>Targeted delivery of cells and therapeutic agents would benefit a wide range of biomedical applications by concentrating the therapeutic effect at the target site while minimizing deleterious effects to off-target sites. Magnetic cell targeting is an efficient, safe, and straightforward delivery technique. Superparamagnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles (SPION) are biodegradable, biocompatible, and can be endocytosed into cells to render them responsive to magnetic fields. The synthesis process involves creating magnetite (Fe3O4) nanoparticles followed by high-speed emulsification to form a poly(lactic-co-glycolic acid) (PLGA) coating. The PLGA-magnetite SPIONs are approximately 120 nm in diameter including the approximately 10 nm diameter magnetite core. When placed in culture medium, SPIONs are naturally endocytosed by cells and stored as small clusters within cytoplasmic endosomes. These particles impart sufficient magnetic mass to the cells to allow for targeting within magnetic fields. Numerous cell sorting and targeting applications are enabled by rendering various cell types responsive to magnetic fields. SPIONs have a variety of other biomedical applications as well including use as a medical imaging contrast agent, targeted drug or gene delivery, diagnostic assays, and generation of local hyperthermia for tumor therapy or tissue soldering.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4595597','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4595597"><span id="translatedtitle">Ultrafast optical modification of exchange interactions in <span class="hlt">iron</span> <span class="hlt">oxides</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Mikhaylovskiy, R.V.; Hendry, E.; Secchi, A.; Mentink, J.H.; Eckstein, M.; Wu, A.; Pisarev, R.V.; Kruglyak, V.V.; Katsnelson, M.I.; Rasing, Th.; Kimel, A.V.</p> <p>2015-01-01</p> <p>Ultrafast non-thermal manipulation of magnetization by light relies on either indirect coupling of the electric field component of the light with spins via spin-orbit interaction or direct coupling between the magnetic field component and spins. Here we propose a scenario for coupling between the electric field of light and spins via optical modification of the exchange interaction, one of the strongest quantum effects with strength of 103 Tesla. We demonstrate that this isotropic opto-magnetic effect, which can be called inverse magneto-refraction, is allowed in a material of any symmetry. Its existence is corroborated by the experimental observation of terahertz emission by spin resonances optically excited in a broad class of <span class="hlt">iron</span> <span class="hlt">oxides</span> with a canted spin configuration. From its strength we estimate that a sub-picosecond modification of the exchange interaction by laser pulses with fluence of about 1 mJ cm−2 acts as a pulsed effective magnetic field of 0.01 Tesla. PMID:26373688</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/330545','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/330545"><span id="translatedtitle">Leaching of pyrite by acidophilic heterotrophic <span class="hlt">iron-oxidizing</span> bacteria in pure and mixed cultures</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Bacelar-Nicolau, P.; Johnson, D.B.</p> <p>1999-02-01</p> <p>Seven strains of heterotrophic <span class="hlt">iron-oxidizing</span> acidophilic bacteria were examined to determine their abilities to promote <span class="hlt">oxidative</span> dissolution of pyrite (FeS{sub 2}) when they were grown in pure cultures and in mixed cultures with sulfur-<span class="hlt">oxidizing</span> Thiobacillus spp. Only one of the isolates (strain T-24) <span class="hlt">oxidized</span> pyrite when it was grown in pyrite-basal salts medium. However, when pyrite-containing cultures were supplemented with 0.02% (wt/vol) yeast extract, most of the isolates <span class="hlt">oxidized</span> pyrite, and one (strain T-24) promoted rates of mineral dissolution similar to the rates observed with the <span class="hlt">iron-oxidizing</span> autotroph Thiobacillus ferroxidans. Pyrite <span class="hlt">oxidation</span> by another isolate (strain T-21) occurred in cultures containing between 0.005 and 0.05% (wt/vol) yeast extract but was completely inhibited in cultures containing 0.5% yeast extract. Ferrous <span class="hlt">iron</span> was also needed for mineral dissolution by the <span class="hlt">iron-oxidizing</span> heterotrophs, indicating that these organisms <span class="hlt">oxidize</span> pyrite via the indirect mechanism. Mixed cultures of three isolates (strains T-21, T-232, and T-24) and the sulfur-<span class="hlt">oxidizing</span> autotroph Thiobacillus thiooxidans promoted pyrite dissolution; since neither strains T-21 and T-23 nor T. thiooxidans could <span class="hlt">oxidize</span> this mineral in yeast extract-free media, this was a novel example of bacterial synergism. Mixed cultures of strains T-21 and T-23 and the sulfur-<span class="hlt">oxidizing</span> mixotroph Thiobacillus acidophilus also <span class="hlt">oxidized</span> pyrite but to a lesser extent than did mixed cultures containing T. thiooxidans. Pyrite leaching by strain T -23 grown in an organic compound-rich medium and incubated either shaken or unshaken was also assessed. The potential environmental significance of <span class="hlt">iron-oxidizing</span> heterotrophs in accelerating pyrite <span class="hlt">oxidation</span> is discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016APS..MAR.S5005O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016APS..MAR.S5005O"><span id="translatedtitle">Unusual phase transition in a natural heterostructure of <span class="hlt">iron</span> pnictides and vanadium <span class="hlt">oxides</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ok, Jong Mok; Baek, S.-H.; Eom, Man Jin; Hoch, C.; Kremer, R. K.; Kim, Dong-Hwan; Chang, Chun-Fu; Ko, Kyung-Tae; Park, Sang-Youn; Ji, Sung Dae; Büchner, B.; Park, Jae-Hoon; Shim, J. H.; Mazin, I. I.; Kim, Jun Sung</p> <p></p> <p>We report the unusual phase transition in Sr2VO3FeAs single crystal, where the Mott-insulating vanadium <span class="hlt">oxides</span> and the high-Tc superconducting <span class="hlt">iron</span> pnictides form a natural heterostructure. Clear evidence of the phase transition at T0 = 155 K was observed in the <span class="hlt">iron</span> pnictide layer, not in the vanadium <span class="hlt">oxide</span> layer, using bulk and NMR measurements. Neither magnetic ordering with sufficient spin moment nor symmetry change in the crystal structure has been detected at T0. At Tmag ~ 45 K, far below T0, magnetic transition occurs in the <span class="hlt">iron</span> pnictide layer, while the vanadium <span class="hlt">oxide</span> layer remains nonmagnetic at low temperatures. The complex evolution of various phases in Sr2VO3FeAs is drastically distinct from the phase transitions found in other <span class="hlt">iron</span> pnictides or vanadium <span class="hlt">oxides</span>, highlighting the importance of the additional interlayer coupling between the layers. Equal contribution, corresponding author.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/20748643','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/20748643"><span id="translatedtitle">Identification of <span class="hlt">iron</span> <span class="hlt">oxide</span> impurities in earliest industrial-scale processed platinum</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Weerd, Jaap van der; Rehren, Thilo . E-mail: th.rehren@ucl.ac.uk; Firth, Steven; Clark, Robin J.H. . E-mail: r.j.h.clark@ucl.ac.uk</p> <p>2004-09-15</p> <p>A detailed investigation of <span class="hlt">iron</span> <span class="hlt">oxide</span> inclusions in a 19th century Russian platinum coin is presented. Such coins represent the products of the first industrial-scale purification of platinum metal. The processed metal is far from pure, however, and two types of <span class="hlt">iron</span> <span class="hlt">oxide</span> inclusions are identified by electron microprobe and Raman microscopy. The results show that the inclusions mainly consist of magnetite and haematite. The Raman band of magnetite at 668 cm{sup -1} was found to shift to about 680 cm{sup -1} with an increase in the average <span class="hlt">oxidation</span> state of the <span class="hlt">iron</span>. It is concluded that the <span class="hlt">iron</span> <span class="hlt">oxides</span> are formed during the heating of the platinum metal powder in the manufacturing process.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23813329','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23813329"><span id="translatedtitle">Interaction of aromatic amines with <span class="hlt">iron</span> <span class="hlt">oxides</span>: implications for prebiotic chemistry.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Shanker, Uma; Singh, Gurinder; Kamaluddin</p> <p>2013-06-01</p> <p>The interaction of aromatic amines (aniline, p-chloroaniline, p-toludine and p-anisidine) with <span class="hlt">iron</span> <span class="hlt">oxides</span> (goethite, akaganeite and hematite) has been studied. Maximum uptake of amines was observed around pH 7. The adsorption data obtained at neutral pH were found to follow Langmuir adsorption. Anisidine was found to be a better adsorbate probably due to its higher basicity. In alkaline medium (pH > 8), amines reacted on goethite and akaganeite to give colored products. Analysis of the products by GC-MS showed benzoquinone and azobenzene as the reaction products of aniline while p-anisidine afforded a dimer. IR analysis of the amine-<span class="hlt">iron</span> <span class="hlt">oxide</span> hydroxide adduct suggests that the surface acidity of <span class="hlt">iron</span> <span class="hlt">oxide</span> hydroxides is responsible for the interaction. The present study suggests that <span class="hlt">iron</span> <span class="hlt">oxide</span> hydroxides might have played a role in the stabilization of organic molecules through their surface activity and in prebiotic condensation reactions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=280796&keyword=hydrogen+AND+peroxide&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=68462887&CFTOKEN=59909856','EPA-EIMS'); return false;" href="http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=280796&keyword=hydrogen+AND+peroxide&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=68462887&CFTOKEN=59909856"><span id="translatedtitle">Eco-Friendly Magnetic <span class="hlt">Iron</span> <span class="hlt">Oxide</span> Pillared Montmorillonite for Advanced Catalytic Degradation of Dichlorophenol</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>Eco-friendly pillared montmorillonites, in which the pillars consist of <span class="hlt">iron</span> <span class="hlt">oxide</span> are expected to have interesting and unusual magnetic properties that are applicable for environmental decontamination. Completely “green” and effective composite was synthesized using mild reactio...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JMMM..416..194L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JMMM..416..194L"><span id="translatedtitle">Magnetothermal release of payload from <span class="hlt">iron</span> <span class="hlt">oxide</span>/silica drug delivery agents</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Luong, T. T.; Knoppe, S.; Bloemen, M.; Brullot, W.; Strobbe, R.; Locquet, J.-P.; Verbiest, T.</p> <p>2016-10-01</p> <p>The release of covalently bound Rhodamine B from <span class="hlt">iron</span> <span class="hlt">oxide</span>/mesoporous silica core/shell nanoparticles under magnetically induced heating was studied. The system acts as a model to study drug delivery and payload release under magnetothermal heating.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=187548&keyword=clinical+AND+case&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=70095649&CFTOKEN=79462050','EPA-EIMS'); return false;" href="http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=187548&keyword=clinical+AND+case&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=70095649&CFTOKEN=79462050"><span id="translatedtitle"><span class="hlt">Iron</span> homeostatis and <span class="hlt">oxidative</span> stress in idiopathic pulmonary alveolar proteinosis: a case-control study</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>ABSTRACT: BACKGROUND: Lung injury caused by both inhaled dusts and infectious agents depends on increased availability of <span class="hlt">iron</span> and metal-catalyzed <span class="hlt">oxidative</span> stress. Because inhaled particles, such as silica, and certain infections can cause secondary pulmonary alveolar proteinosi...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1132191','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1132191"><span id="translatedtitle">Effects of <span class="hlt">Iron</span> <span class="hlt">Oxides</span> on the Rheological Properties of Cementitious Slurry</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Chung, Chul-Woo; Chun, Jaehun; Wang, Guohui; Um, Wooyong</p> <p>2014-04-02</p> <p><span class="hlt">Iron</span> <span class="hlt">oxide</span> has been considered a promising host for immobilizing and encapsulating radioactive 99Tc (t1/2=2.1x105 year), which significantly enhances the stability of 99Tc within a cementitious waste form. However, the flow behavior of cementitious slurry containing <span class="hlt">iron</span> <span class="hlt">oxide</span> has never been investigated to ensure its workability, which directly influences the preparation and performance of the cementitious waste form monolith. Variation in the rheological properties of the cementitious slurry were studied using rheometry and ultrasonic wave reflection to understand the effects of various <span class="hlt">iron</span> <span class="hlt">oxides</span> (magnetite, hematite, ferrihydrite, and goethite) during the cement setting and stiffening processes. The rheological behavior significantly varied with the addition of different chemical compounds of <span class="hlt">iron</span> <span class="hlt">oxides</span>. Complementary microscopic characteristics such as colloidal vibration currents, morphology, and particle size distributions further suggest that the most adverse alteration of cement setting and stiffening behavior caused by the presence of goethite may be attributed to its acicular shape.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4613306','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4613306"><span id="translatedtitle">Characterization, Quantification, and Determination of the Toxicity of <span class="hlt">Iron</span> <span class="hlt">Oxide</span> Nanoparticles to the Bone Marrow Cells</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Paik, Sae-Yeol-Rim; Kim, Jong-Seok; Shin, Sung Jae; Ko, Sanghoon</p> <p>2015-01-01</p> <p><span class="hlt">Iron</span> <span class="hlt">oxide</span> nanoparticles (IONPs) have been used to develop <span class="hlt">iron</span> supplements for improving the bioavailability of <span class="hlt">iron</span> in patients with <span class="hlt">iron</span> deficiency, which is one of the most serious nutritional deficiencies in the world. Accurate information about the characteristics, concentration, and cytotoxicity of IONPs to the developmental and reproductive cells enables safe use of IONPs in the supplement industry. The objective of this study was to analyze the physicochemical properties and cytotoxicity of IONPs in bone marrow cells. We prepared three different types of <span class="hlt">iron</span> samples (surface-modified <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles (SMNPs), IONPs, and <span class="hlt">iron</span> citrate) and analyzed their physicochemical properties such as particle size distribution, zeta potential, and morphology. In addition, we examined the cytotoxicity of the IONPs in various kinds of bone marrow cells. We analyzed particle size distribution, zeta potential, <span class="hlt">iron</span> levels, and subcellular localization of the <span class="hlt">iron</span> samples in bone marrow cells. Our results showed that the <span class="hlt">iron</span> samples were not cytotoxic to the bone marrow cells and did not affect the expression of cell surface markers and lipopolysaccharide (LPS)-induced the secretion of cytokines by murine bone marrow-derived dendritic cells (BMDCs). Our results may be used to investigate the interactions between nanoparticles and cells and tissues and the developmental toxicity of nanoparticles. PMID:26389886</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26389886','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26389886"><span id="translatedtitle">Characterization, Quantification, and Determination of the Toxicity of <span class="hlt">Iron</span> <span class="hlt">Oxide</span> Nanoparticles to the Bone Marrow Cells.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Paik, Sae-Yeol-Rim; Kim, Jong-Seok; Shin, Sung Jae; Ko, Sanghoon</p> <p>2015-01-01</p> <p><span class="hlt">Iron</span> <span class="hlt">oxide</span> nanoparticles (IONPs) have been used to develop <span class="hlt">iron</span> supplements for improving the bioavailability of <span class="hlt">iron</span> in patients with <span class="hlt">iron</span> deficiency, which is one of the most serious nutritional deficiencies in the world. Accurate information about the characteristics, concentration, and cytotoxicity of IONPs to the developmental and reproductive cells enables safe use of IONPs in the supplement industry. The objective of this study was to analyze the physicochemical properties and cytotoxicity of IONPs in bone marrow cells. We prepared three different types of <span class="hlt">iron</span> samples (surface-modified <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles (SMNPs), IONPs, and <span class="hlt">iron</span> citrate) and analyzed their physicochemical properties such as particle size distribution, zeta potential, and morphology. In addition, we examined the cytotoxicity of the IONPs in various kinds of bone marrow cells. We analyzed particle size distribution, zeta potential, <span class="hlt">iron</span> levels, and subcellular localization of the <span class="hlt">iron</span> samples in bone marrow cells. Our results showed that the <span class="hlt">iron</span> samples were not cytotoxic to the bone marrow cells and did not affect the expression of cell surface markers and lipopolysaccharide (LPS)-induced the secretion of cytokines by murine bone marrow-derived dendritic cells (BMDCs). Our results may be used to investigate the interactions between nanoparticles and cells and tissues and the developmental toxicity of nanoparticles.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26592710','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26592710"><span id="translatedtitle">Formation of biomineral <span class="hlt">iron</span> <span class="hlt">oxides</span> compounds in a Fe hyperaccumulator plant: Imperata cylindrica (L.) P. Beauv.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Fuente, V; Rufo, L; Juárez, B H; Menéndez, N; García-Hernández, M; Salas-Colera, E; Espinosa, A</p> <p>2016-01-01</p> <p>We report a detailed work of composition and location of naturally formed <span class="hlt">iron</span> biominerals in plant cells tissues grown in <span class="hlt">iron</span> rich environments as Imperata cylindrica. This perennial grass grows on the Tinto River banks (Iberian Pyritic Belt) in an extreme acidic ecosystem (pH∼2.3) with high concentration of dissolved <span class="hlt">iron</span>, sulphate and heavy metals. <span class="hlt">Iron</span> biominerals were found at the cellular level in tissues of root, stem and leaf both in collected and laboratory-cultivated plants. <span class="hlt">Iron</span> accumulated in this plant as a mix of <span class="hlt">iron</span> compounds (mainly as jarosite, ferrihydrite, hematite and spinel phases) was characterized by X-ray diffraction (XRD), X-ray absorption spectroscopy (XAS), Mössbauer spectroscopy (MS), magnetometry (SQUID), electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX; TEM-EDX; HRSTEM). A low fraction of phosphorous was detected in this <span class="hlt">iron</span> hyperaccumulator plant. Root and rhizomes tissues present a high proportion of ferromagnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> compounds. <span class="hlt">Iron</span> <span class="hlt">oxides</span>-rich zones are localized in electron dense intra and inter-cellular aggregates that appear as dark deposits covering the inner membrane and organelles of the cell. This study aims to contribute to a better understanding of the mechanisms of accumulation, transport, distribution of <span class="hlt">iron</span> in Imperata cylindrica.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26592710','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26592710"><span id="translatedtitle">Formation of biomineral <span class="hlt">iron</span> <span class="hlt">oxides</span> compounds in a Fe hyperaccumulator plant: Imperata cylindrica (L.) P. Beauv.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Fuente, V; Rufo, L; Juárez, B H; Menéndez, N; García-Hernández, M; Salas-Colera, E; Espinosa, A</p> <p>2016-01-01</p> <p>We report a detailed work of composition and location of naturally formed <span class="hlt">iron</span> biominerals in plant cells tissues grown in <span class="hlt">iron</span> rich environments as Imperata cylindrica. This perennial grass grows on the Tinto River banks (Iberian Pyritic Belt) in an extreme acidic ecosystem (pH∼2.3) with high concentration of dissolved <span class="hlt">iron</span>, sulphate and heavy metals. <span class="hlt">Iron</span> biominerals were found at the cellular level in tissues of root, stem and leaf both in collected and laboratory-cultivated plants. <span class="hlt">Iron</span> accumulated in this plant as a mix of <span class="hlt">iron</span> compounds (mainly as jarosite, ferrihydrite, hematite and spinel phases) was characterized by X-ray diffraction (XRD), X-ray absorption spectroscopy (XAS), Mössbauer spectroscopy (MS), magnetometry (SQUID), electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX; TEM-EDX; HRSTEM). A low fraction of phosphorous was detected in this <span class="hlt">iron</span> hyperaccumulator plant. Root and rhizomes tissues present a high proportion of ferromagnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> compounds. <span class="hlt">Iron</span> <span class="hlt">oxides</span>-rich zones are localized in electron dense intra and inter-cellular aggregates that appear as dark deposits covering the inner membrane and organelles of the cell. This study aims to contribute to a better understanding of the mechanisms of accumulation, transport, distribution of <span class="hlt">iron</span> in Imperata cylindrica. PMID:26592710</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21121369','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21121369"><span id="translatedtitle"><span class="hlt">Oxidative</span> stress and apoptosis induced by <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles in cultured human umbilical endothelial cells.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhu, Mo-Tao; Wang, Yun; Feng, Wei-Yue; Wang, Bing; Wang, Meng; Ouyang, Hong; Chai, Zhi-Fang</p> <p>2010-12-01</p> <p>Recent epidemiologic researches indicate that exposure to ultrafine particles (nanoparticles) is an independent risk factor for several cardiovascular diseases. The induction of endothelial injuries is hypothesized to be an attractive mechanism involved in these cardiovascular diseases. To investigate this hypothesis, the widely used <span class="hlt">iron</span> nanomaterials, ferric <span class="hlt">oxide</span> (Fe2O3) and ferriferrous <span class="hlt">oxide</span> (Fe3O4) nanoparticles were incubated with human umbilical endothelial cells (ECV304 cells) at different concentrations of 2, 20, 100 microg/mL. The cell viability, the rate of apoptosis, the apoptotic nuclear morphology and the mitochondria membrane potential were measured to estimate the cell necrosis and apoptosis caused by the nanoparticle exposure. The stimulation of superoxide anion (O2*-) and nitric <span class="hlt">oxide</span> (NO) were examined to evaluate the stress responses of endothelial cells. Our results indicated that both the Fe2O3 and Fe3O4 nanoparticles could generate <span class="hlt">oxidative</span> stress as well as the significant increase of nitric <span class="hlt">oxide</span> in ECV304 cells. The loss of mitochondria membrane potential and the apoptotic chromatin condensation in the nucleus were observed as the early signs of apoptosis. It is inferred the stress response might be an important mechanism involving in endothelial cells apoptosis and death, and these injuries in endothelial cells might play a key role in downstream cardiovascular diseases such as atheroscelerosis, hypertension and myocardial infarction (MI).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002AGUFM.B72A0756C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002AGUFM.B72A0756C"><span id="translatedtitle">Microbial Communities Associated with Biogenic <span class="hlt">Iron</span> <span class="hlt">Oxide</span> Mineralization in Circumneutral pH Environments</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chan, C. S.; Banfield, J. F.</p> <p>2002-12-01</p> <p>Lithotrophic growth on <span class="hlt">iron</span> is a metabolism that has been found in a variety of neutral pH environments and is likely important in sustaining life in microaerophilic solutions, especially those low in organics. The composition of the microbial communities, especially the organisms that are responsible for <span class="hlt">iron</span> <span class="hlt">oxidation</span>, and carbon and nitrogen fixation, are not known, yet the ability to recognize these contributions is vital to our understanding of <span class="hlt">iron</span> cycling in natural environments. Our approach has been to study the microbial community structure, mineralogy, and geochemistry of ~20 cm thick, 100's meters long, fluffy <span class="hlt">iron</span> <span class="hlt">oxide</span>-encrusted biological mats growing in the Piquette Mine tunnel, and to compare the results to those from geochemically similar environments. In situ measurements (Hydrolab) and geochemical characterization of bulk water samples and peepers (dialysis sampling vials) indicate that the environment is microaerobic, with micromolar levels of <span class="hlt">iron</span>, high carbonate and sulfate, and typical groundwater nitrate and nitrite concentrations. 16S rDNA clone libraries show that the microbial mat and water contain communities with considerable diversity within the Bacterial domain, a large proportion of Nitrospira and Betaproteobacteria, and no Archaea. Because clone library data are not necessarily indicative of actual abundance, fluorescence in-situ hybridization (FISH) was performed on water, mat, and sediment samples from the Piquette mine and two circumneutral <span class="hlt">iron</span>- and carbonate-rich springs in the Oregon Cascade Range. Domain- and phylum-level probes were chosen based on the clone library results (Nitrospira, Beta- and Gammaproteobacteria, Acidobacteria, Actinobacteria, Chloroflexi, and Planctomyces). FISH data reveal spatial associations between specific microbial groups and mineralized structures. The organisms responsible for making the mineralized sheaths that compose the bulk of the <span class="hlt">iron</span> <span class="hlt">oxide</span> mat are Betaproteobacteria (probably Leptothrix</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ods.od.nih.gov/factsheets/Iron-Consumer/','NIH-MEDLINEPLUS'); return false;" href="https://ods.od.nih.gov/factsheets/Iron-Consumer/"><span id="translatedtitle"><span class="hlt">Iron</span></span></a></p> <p><a target="_blank" href="http://medlineplus.gov/">MedlinePlus</a></p> <p></p> <p></p> <p>... cereals and breads. White beans, lentils, spinach, kidney beans, and peas. Nuts and some dried fruits, such as raisins. <span class="hlt">Iron</span> in food comes in two forms: heme <span class="hlt">iron</span> and nonheme <span class="hlt">iron</span>. Nonheme <span class="hlt">iron</span> is found in plant foods and <span class="hlt">iron</span>-fortified food products. Meat, seafood, ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/900437','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/900437"><span id="translatedtitle">Influence of <span class="hlt">Iron</span> <span class="hlt">Oxide</span> Particles on the Strength of Ball-Milled <span class="hlt">Iron</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Lesuer, D R; Syn, C K; Sherby, O D</p> <p>2005-12-07</p> <p>Detailed microstructural and mechanical property studies of ball-milled <span class="hlt">iron</span>, in the powder and consolidated states, are reviewed and assessed. The analyses cover three and one-half orders of magnitude of grain size (from 6 nm to 20 mm) and focus on the influence of <span class="hlt">oxide</span> particles on the strength. The study includes the early work of Koch and Yang, Kimura and Takaki and continues with the more recent work of Umemoto et al and Belyakov, Sakai et al. It is shown that the major contributors to strength are the nanooxide particles. These particles are created by adiabatic shear banding during ball-milling leading to a bimodal distribution of particles. The predicted strength from particles, {sigma}{sub p}, is given by {sigma}{sub p} = B {center_dot} (D*{sub S}){sup -1/2} where D*{sub S} is the surface-to-surface interparticle spacing, and B = 395 MPa {center_dot} {micro}m{sup -1/2}. A model is proposed that accounts for the influence of the bimodal particle size distribution on strength.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18288791','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18288791"><span id="translatedtitle">Poly(L-lysine)-modified <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles for stem cell labeling.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Babic, Michal; Horák, Daniel; Trchová, Miroslava; Jendelová, Pavla; Glogarová, Katerina; Lesný, Petr; Herynek, Vít; Hájek, Milan; Syková, Eva</p> <p>2008-03-01</p> <p>New surface-modified <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles were developed by precipitation of Fe(II) and Fe(III) salts with ammonium hydroxide and <span class="hlt">oxidation</span> of the resulting magnetite with sodium hypochlorite, followed by the addition of poly( L-lysine) (PLL) solution. PLL of several molecular weights ranging from 146 ( L-lysine) to 579 000 was tested as a coating to boost the intracellular uptake of the nanoparticles. The nanoparticles were characterized by TEM, dynamic light scattering, FTIR, and ultrasonic spectrometry. TEM revealed that the particles were ca. 6 nm in diameter, while FTIR showed that their surfaces were well-coated with PLL. The interaction of PLL-modified <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles with DMEM culture medium was verified by UV-vis spectroscopy. Rat bone marrow stromal cells (rMSCs) and human mesenchymal stem cells (hMSC) were labeled with PLL-modified <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles or with Endorem (control). Optical microscopy and TEM confirmed the presence of PLL-modified <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles inside the cells. Cellular uptake was very high (more than 92%) for PLL-modified nanoparticles that were coated with PLL (molecular weight 388 00) at a concentration of 0.02 mg PLL per milliliter of colloid. The cellular uptake of PLL-modified <span class="hlt">iron</span> <span class="hlt">oxide</span> was facilitated by its interaction with the negatively charged cell surface and subsequent endosomolytic uptake. The relaxivity of rMSCs labeled with PLL-modified <span class="hlt">iron</span> <span class="hlt">oxide</span> and the amount of <span class="hlt">iron</span> in the cells were determined. PLL-modified <span class="hlt">iron</span> <span class="hlt">oxide</span>-labeled rMSCs were imaged in vitro and in vivo after intracerebral grafting into the contralateral hemisphere of the adult rat brain. The implanted cells were visible on magnetic resonance (MR) images as a hypointense area at the injection site and in the lesion. In comparison with Endorem, nanoparticles modified with PLL of an optimum molecular weight demonstrated a higher efficiency of intracellular uptake by MSC cells.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23450737','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23450737"><span id="translatedtitle">A microbial-mineralization approach for syntheses of <span class="hlt">iron</span> <span class="hlt">oxides</span> with a high specific surface area.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yagita, Naoki; Oaki, Yuya; Imai, Hiroaki</p> <p>2013-04-01</p> <p>Of minerals and microbes: A microbial-mineralization-inspired approach was used to facilitate the syntheses of <span class="hlt">iron</span> <span class="hlt">oxides</span> with a high specific surface area, such as 253 m(2)g(-1) for maghemite (γ-Fe(2)O(3)) and 148 m(2)g(-1) for hematite (α-Fe(2)O(3)). These <span class="hlt">iron</span> <span class="hlt">oxides</span> can be applied to electrode material of lithium-ion batteries, adsorbents, and catalysts.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009E%26PSL.286..230P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009E%26PSL.286..230P"><span id="translatedtitle"><span class="hlt">Iron-oxidizing</span> microbial ecosystems thrived in late Paleoproterozoic redox-stratified oceans</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Planavsky, Noah; Rouxel, Olivier; Bekker, Andrey; Shapiro, Russell; Fralick, Phil; Knudsen, Andrew</p> <p>2009-08-01</p> <p>We conducted a geochemical and petrographic study of the 1.89 billion year old Gunflint and Biwabik <span class="hlt">iron</span> formations, with the goal of determining the importance of microbial <span class="hlt">iron-oxidation</span> in the formation of <span class="hlt">iron</span>- and microfossil-rich stromatolites. We used redox-sensitive tracers, such as <span class="hlt">iron</span> isotopes and rare earth elements, to decipher whether these ancient microbial ecosystems harbored cyanobacteria or Fe-<span class="hlt">oxidizing</span> bacteria as primary producers. <span class="hlt">Iron</span>-rich stromatolites contain non-significant or positive Ce anomalies, which contrast with shallow water deposits having negative Ce anomalies. This trend in Ce anomalies indicates that the stromatolites formed in low oxygen conditions, which is the ideal setting for the proliferation of Fe-<span class="hlt">oxidizing</span> bacterial ecosystems. The stromatolites yield a large range of δ 56Fe values, from -0.66 to +0.82‰, but contain predominantly positive values indicating the prevalence of partial Fe-<span class="hlt">oxidation</span>. Based on modern analogues, Fe-<span class="hlt">oxides</span> precipitated in cyanobacterial mats are expected to record an isotopic signature of quantitative <span class="hlt">oxidation</span>, which in marine settings will yield negative δ 56Fe values. The stromatolite <span class="hlt">iron</span> isotope data, therefore, provide evidence for the presence of Fe-<span class="hlt">oxidizing</span> bacteria. The stromatolites can be traced for a distance of over 100 km in these <span class="hlt">iron</span> formations, indicating that they record a pervasive rather than localized ecosystem. Their preservation in late Paleoproterozoic successions deposited along the margins of the Superior craton suggests that there was a global expansion of <span class="hlt">iron-oxidizing</span> bacterial communities at shallow-water redox boundaries in late Paleoproterozoic oceans.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26100970','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26100970"><span id="translatedtitle">Tunable room-temperature ferromagnet using an <span class="hlt">iron-oxide</span> and graphene <span class="hlt">oxide</span> nanocomposite.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lin, Aigu L; Rodrigues, J N B; Su, Chenliang; Milletari, M; Loh, Kian Ping; Wu, Tom; Chen, Wei; Neto, A H Castro; Adam, Shaffique; Wee, Andrew T S</p> <p>2015-01-01</p> <p>Magnetic materials have found wide application ranging from electronics and memories to medicine. Essential to these advances is the control of the magnetic order. To date, most room-temperature applications have a fixed magnetic moment whose orientation is manipulated for functionality. Here we demonstrate an <span class="hlt">iron-oxide</span> and graphene <span class="hlt">oxide</span> nanocomposite based device that acts as a tunable ferromagnet at room temperature. Not only can we tune its transition temperature in a wide range of temperatures around room temperature, but the magnetization can also be tuned from zero to 0.011 A m(2)/kg through an initialization process with two readily accessible knobs (magnetic field and electric current), after which the system retains its magnetic properties semi-permanently until the next initialization process. We construct a theoretical model to illustrate that this tunability originates from an indirect exchange interaction mediated by spin-imbalanced electrons inside the nanocomposite. PMID:26100970</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015NatSR...511430L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015NatSR...511430L"><span id="translatedtitle">Tunable room-temperature ferromagnet using an <span class="hlt">iron-oxide</span> and graphene <span class="hlt">oxide</span> nanocomposite</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lin, Aigu L.; Rodrigues, J. N. B.; Su, Chenliang; Milletari, M.; Loh, Kian Ping; Wu, Tom; Chen, Wei; Neto, A. H. Castro; Adam, Shaffique; Wee, Andrew T. S.</p> <p>2015-06-01</p> <p>Magnetic materials have found wide application ranging from electronics and memories to medicine. Essential to these advances is the control of the magnetic order. To date, most room-temperature applications have a fixed magnetic moment whose orientation is manipulated for functionality. Here we demonstrate an <span class="hlt">iron-oxide</span> and graphene <span class="hlt">oxide</span> nanocomposite based device that acts as a tunable ferromagnet at room temperature. Not only can we tune its transition temperature in a wide range of temperatures around room temperature, but the magnetization can also be tuned from zero to 0.011 A m2/kg through an initialization process with two readily accessible knobs (magnetic field and electric current), after which the system retains its magnetic properties semi-permanently until the next initialization process. We construct a theoretical model to illustrate that this tunability originates from an indirect exchange interaction mediated by spin-imbalanced electrons inside the nanocomposite.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016Nanos...812683X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016Nanos...812683X"><span id="translatedtitle">Long circulating reduced graphene <span class="hlt">oxide-iron</span> <span class="hlt">oxide</span> nanoparticles for efficient tumor targeting and multimodality imaging</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xu, Cheng; Shi, Sixiang; Feng, Liangzhu; Chen, Feng; Graves, Stephen A.; Ehlerding, Emily B.; Goel, Shreya; Sun, Haiyan; England, Christopher G.; Nickles, Robert J.; Liu, Zhuang; Wang, Taihong; Cai, Weibo</p> <p>2016-06-01</p> <p>Polyethylene glycol (PEG) surface modification is one of the most widely used approaches to improve the solubility of inorganic nanoparticles, prevent their aggregation and prolong their in vivo blood circulation half-life. Herein, we developed double-PEGylated biocompatible reduced graphene <span class="hlt">oxide</span> nanosheets anchored with <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles (RGO-IONP-1stPEG-2ndPEG). The nanoconjugates exhibited a prolonged blood circulation half-life (~27.7 h) and remarkable tumor accumulation (>11 %ID g-1) via an enhanced permeability and retention (EPR) effect. Due to the strong near-infrared absorbance and superparamagnetism of RGO-IONP-1stPEG-2ndPEG, multimodality imaging combining positron emission tomography (PET) imaging with magnetic resonance imaging (MRI) and photoacoustic (PA) imaging was successfully achieved. The promising results suggest the great potential of these nanoconjugates for multi-dimensional and more accurate tumor diagnosis and therapy in the future.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26059262','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26059262"><span id="translatedtitle">Synthesis of phase-pure and monodisperse <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles by thermal decomposition.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hufschmid, Ryan; Arami, Hamed; Ferguson, R Matthew; Gonzales, Marcela; Teeman, Eric; Brush, Lucien N; Browning, Nigel D; Krishnan, Kannan M</p> <p>2015-07-01</p> <p>Superparamagnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles (SPIONs) are used for a wide range of biomedical applications requiring precise control over their physical and magnetic properties, which are dependent on their size and crystallographic phase. Here we present a comprehensive template for the design and synthesis of <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles with control over size, size distribution, phase, and resulting magnetic properties. We investigate critical parameters for synthesis of monodisperse SPIONs by organic thermal decomposition. Three different, commonly used, <span class="hlt">iron</span> containing precursors (<span class="hlt">iron</span> oleate, <span class="hlt">iron</span> pentacarbonyl, and <span class="hlt">iron</span> oxyhydroxide) are evaluated under a variety of synthetic conditions. We compare the suitability of these three kinetically controlled synthesis protocols, which have in common the use of <span class="hlt">iron</span> oleate as a starting precursor or reaction intermediate, for producing nanoparticles with specific size and magnetic properties. Monodisperse particles were produced over a tunable range of sizes from approximately 2-30 nm. Reaction parameters such as precursor concentration, addition of surfactant, temperature, ramp rate, and time were adjusted to kinetically control size and size-distribution, phase, and magnetic properties. In particular, large quantities of excess surfactant (up to 25 : 1 molar ratio) alter reaction kinetics and result in larger particles with uniform size; however, there is often a trade-off between large particles and a narrow size distribution. <span class="hlt">Iron</span> <span class="hlt">oxide</span> phase, in addition to nanoparticle size and shape, is critical for establishing magnetic properties such as differential susceptibility (dm/dH) and anisotropy. As an example, we show the importance of obtaining the required size and <span class="hlt">iron</span> <span class="hlt">oxide</span> phase for application to Magnetic Particle Imaging (MPI), and describe how phase purity can be controlled. These results provide much of the information necessary to determine which <span class="hlt">iron</span> <span class="hlt">oxide</span> synthesis protocol is best suited to a particular</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24184048','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24184048"><span id="translatedtitle">Persulfate activation by <span class="hlt">iron</span> <span class="hlt">oxide</span>-immobilized MnO2 composite: identification of <span class="hlt">iron</span> <span class="hlt">oxide</span> and the optimum pH for degradations.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Jo, Young-Hoon; Do, Si-Hyun; Kong, Sung-Ho</p> <p>2014-01-01</p> <p><span class="hlt">Iron</span> <span class="hlt">oxide</span>-immobilized manganese <span class="hlt">oxide</span> (MnO2) composite was prepared and the reactivity of persulfate (PS) with the composite as activator was investigated for degradation of carbon tetrachloride and benzene at various pH levels. Brunauer-Emmett-Teller (BET) surface area of the composite was similar to that of pure MnO2 while the pore volume and diameter of composite was larger than those of MnO2. Scanning electron microscopy couples with energy dispersive spectroscopy (SEM-EDS) showed that Fe and Mn were detected on the surface of the composite, and X-ray diffraction (XRD) analysis indicated the possibilities of the existence of various <span class="hlt">iron</span> <span class="hlt">oxides</span> on the composite surface. Furthermore, the analyses of X-ray photoelectron (XPS) spectra revealed that the <span class="hlt">oxidation</span> state of <span class="hlt">iron</span> was identified as 1.74. In PS/composite system, the same pH for the highest degradation rates of both carbon tetrachloride and benzene were observed and the value of pH was 9. Scavenger test was suggested that both <span class="hlt">oxidants</span> (i.e. hydroxyl radical, sulfate radical) and reductant (i.e. superoxide anion) were effectively produced when PS was activated with the <span class="hlt">iron</span>-immobilized MnO2.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22074183','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22074183"><span id="translatedtitle">Adsorption of poly(vinyl formamide-co-vinyl amine) (PVFA-co-PVAm) polymers on zinc, zinc <span class="hlt">oxide</span>, <span class="hlt">iron</span>, and <span class="hlt">iron</span> <span class="hlt">oxide</span> surfaces.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Seifert, Susan; Simon, Frank; Baumann, Giesela; Hietschold, Michael; Seifert, Andreas; Spange, Stefan</p> <p>2011-12-01</p> <p>The adsorption of poly(vinyl formamide) (PVFA) and the statistic copolymers poly(vinyl formamide-co-vinyl amine) (PVFA-co-PVAm) onto zinc and <span class="hlt">iron</span> metal particles as well as their <span class="hlt">oxides</span> was investigated. The adsorbates were characterized by means of XPS, DRIFT spectroscopy, wet chemical analysis, and solvatochromic probes. Dicyano-bis-(1,10-phenanthroline)-<span class="hlt">iron</span>(II) (1), 3-(4-amino-3-methylphenyl)-7-phenyl-benzo-[1,2-b:4,5-b']difuran-2,6-dione (2), and 4-tert-butyl-2-(dicyano-methylene)-5-[4-(diethylamino)-benzylidene]-Δ(3)-thiazoline (3) as solvatochromic probes were coadsorbed onto zinc <span class="hlt">oxide</span> to measure various effects of surface polarity. The experimental findings showed that the adsorption mechanism of PVFA and PVFA-co-PVAm strongly depends on the degree of hydrolysis of PVFA and pH values and also on the kind of metal or metal <span class="hlt">oxide</span> surfaces that were employed as adsorbents. The adsorption mechanism of PVFA/PVFA-co-PVAm onto zinc <span class="hlt">oxide</span> and <span class="hlt">iron</span> <span class="hlt">oxide</span> surfaces is mainly affected by electrostatic interactions. Particularly in the region of pH 5, the adsorption of PVFA/PVFA-co-PVAm onto zinc and <span class="hlt">iron</span> metal particles is additionally influenced by redox processes, dissolution, and complexation reactions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/22580341','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/22580341"><span id="translatedtitle">A novel strategy of natural plant ferritin to protect DNA from <span class="hlt">oxidative</span> damage during <span class="hlt">iron</span> <span class="hlt">oxidation</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Liao, Xiayun; Lv, Chenyan; Zhang, Xiuqing; Masuda, Taro; Li, Meiliang; Zhao, Guanghua</p> <p>2012-07-15</p> <p>Plant ferritin is a naturally occurring heteropolymer in plastids, where Fe(2+) is <span class="hlt">oxidatively</span> deposited into the protein. However, the effect of this process on the coexistence of DNA and plant ferritin in the plastids is unknown. To investigate this effect, we built a system in which various plant ferritins and DNA coexist, followed by treatment with ferrous ions under aerobic conditions. Interestingly, naturally occurring soybean seed ferritin (SSF), a heteropolymer with an H-1/H-2 ratio of 1 to 1 in the apo form, completely protected DNA from <span class="hlt">oxidative</span> damage during <span class="hlt">iron</span> <span class="hlt">oxidative</span> deposition into protein, and a similar result was obtained with its recombinant form, but not with its homopolymeric counterparts, apo rH-1 and apo rH-2. We demonstrate that the difference in DNA protection between heteropolymeric and homopolymeric plant ferritins stems from their different strategies to control <span class="hlt">iron</span> chemistry during the above <span class="hlt">oxidative</span> process. For example, the detoxification reaction occurs only in the presence of apo heteropolymeric SSF (hSSF), thereby preventing the production of hydroxyl radicals. In contrast, hydroxyl radicals are apparently generated via the Fenton reaction when apo rH-1 or rH-2 is used instead of apo hSSF. Thus, a combination of H-1 and H-2 subunits in hSSF seems to impart a unique DNA-protective function to the protein, which was previously unrecognized. This new finding advances our understanding of the structure and function of ferritin and of the widespread occurrence of heteropolymeric plant ferritin in nature. PMID:22580341</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24184442','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24184442"><span id="translatedtitle">Long-term aerobic exercise increases redox-active <span class="hlt">iron</span> through nitric <span class="hlt">oxide</span> in rat hippocampus.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Chen, Qian; Xiao, De-Sheng</p> <p>2014-01-30</p> <p>Adult hippocampus is highly vulnerable to <span class="hlt">iron</span>-induced <span class="hlt">oxidative</span> stress. Aerobic exercise has been proposed to reduce <span class="hlt">oxidative</span> stress but the findings in the hippocampus are conflicting. This study aimed to observe the changes of redox-active <span class="hlt">iron</span> and concomitant regulation of cellular <span class="hlt">iron</span> homeostasis in the hippocampus by aerobic exercise, and possible regulatory effect of nitric <span class="hlt">oxide</span> (NO). A randomized controlled study was designed in the rats with swimming exercise treatment (for 3 months) and/or an unselective inhibitor of NO synthase (NOS) (L-NAME) treatment. The results from the bleomycin-detectable <span class="hlt">iron</span> assay showed additional redox-active <span class="hlt">iron</span> in the hippocampus by exercise treatment. The results from nonheme <span class="hlt">iron</span> content assay, combined with the redox-active <span class="hlt">iron</span> content, showed increased storage <span class="hlt">iron</span> content by exercise treatment. NOx (nitrate plus nitrite) assay showed increased NOx content by exercise treatment. The results from the Western blot assay showed decreased ferroportin expression, no changes of TfR1 and DMT1 expressions, increased IRP1 and IRP2 expression, increased expressions of eNOS and nNOS rather than iNOS. In these effects of exercise treatment, the increased redox-active <span class="hlt">iron</span> content, storage <span class="hlt">iron</span> content, IRP1 and IRP2 expressions were completely reversed by L-NAME treatment, and decreased ferroportin expression was in part reversed by L-NAME. L-NAME treatment completely inhibited increased NOx and both eNOS and nNOS expression in the hippocampus. Our findings suggest that aerobic exercise could increase the redox-active <span class="hlt">iron</span> in the hippocampus, indicating an increase in the capacity to generate hydroxyl radicals through the Fenton reactions, and aerobic exercise-induced <span class="hlt">iron</span> accumulation in the hippocampus might mainly result from the role of the endogenous NO.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014ChPhB..23c7503S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014ChPhB..23c7503S"><span id="translatedtitle">Magnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles: Synthesis and surface coating techniques for biomedical applications</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sun, Sheng-Nan; Wei, Chao; Zhu, Zan-Zan; Hou, Yang-Long; Subbu, S. Venkatraman; Xu, Zhi-Chuan</p> <p>2014-03-01</p> <p><span class="hlt">Iron</span> <span class="hlt">oxide</span> nanoparticles are the most popular magnetic nanoparticles used in biomedical applications due to their low cost, low toxicity, and unique magnetic property. Magnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles, including magnetite (Fe3O4) and maghemite (γ-Fe2O3), usually exhibit a superparamagnetic property as their size goes smaller than 20 nm, which are often denoted as superparamagnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles (SPIONs) and utilized for drug delivery, diagnosis, therapy, and etc. This review article gives a brief introduction on magnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles in terms of their fundamentals of magnetism, magnetic resonance imaging (MRI), and drug delivery, as well as the synthesis approaches, surface coating, and application examples from recent key literatures. Because the quality and surface chemistry play important roles in biomedical applications, our review focuses on the synthesis approaches and surface modifications of <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles. We aim to provide a detailed introduction to readers who are new to this field, helping them to choose suitable synthesis methods and to optimize the surface chemistry of <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles for their interests.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3834165','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3834165"><span id="translatedtitle">Induced Clustered Nanoconfinement of Superparamagnetic <span class="hlt">Iron</span> <span class="hlt">Oxide</span> in Biodegradable Nanoparticles Enhances Transverse Relaxivity for Targeted Theranostics</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Ragheb, Ragy R. T.; Kim, Dongin; Bandyopadhyay, Arunima; Chahboune, Halima; Bulutoglu, Beyza; Ezaldein, Harib; Criscione, Jason M.; Fahmy, Tarek M.</p> <p>2013-01-01</p> <p>Purpose Combined therapeutic and diagnostic agents, “theranostics” are emerging valuable tools for noninvasive imaging and drug delivery. Here, we report on a solid biodegradable multifunctional nanoparticle that combines both features. Methods Poly(lactide-co-glycolide) nanoparticles were engineered to confine superparamagnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> contrast for magnetic resonance imaging while enabling controlled drug delivery and targeting to specific cells. To achieve this dual modality, fatty acids were used as anchors for surface ligands and for encapsulated <span class="hlt">iron</span> <span class="hlt">oxide</span> in the polymer matrix. Results We demonstrate that fatty acid modified <span class="hlt">iron</span> <span class="hlt">oxide</span> prolonged retention of the contrast agent in the polymer matrix during degradative release of drug. Antibody-fatty acid surface modification facilitated cellular targeting and subsequent internalization in cells while inducing clustering of encapsulated fatty-acid modified superparamagnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> during particle formulation. This induced clustered confinement led to an aggregation within the nanoparticle and, hence, higher transverse relaxivity, r2, (294 mM−1 s−1) compared with nanoparticles without fatty-acid ligands (160 mM−1 s−1) and higher than commercially available superparamagnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles (89 mM−1 s−1). Conclusion Clustering of superparamagnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> in poly(lactide-co-glycolide) did not affect the controlled release of encapsulated drugs such as methotrexate or clodronate and their subsequent pharmacological activity, thus highlighting the full theranostic capability of our system. PMID:23401099</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.B13C0638G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.B13C0638G"><span id="translatedtitle">Dominance of Ferritrophicum populations at an AMD site with rapid <span class="hlt">iron</span> <span class="hlt">oxidation</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Grettenberger, C.; Pearce, A.; Bibby, K. J.; Burgos, W.; Jones, D. S.; Macalady, J.</p> <p>2015-12-01</p> <p>Acid mine drainage is a major environmental problem affecting watersheds across the globe. Bioremediation of AMD relies on microbial communities to <span class="hlt">oxidize</span> and thus remove <span class="hlt">iron</span> from the system. <span class="hlt">Iron-oxidation</span> rates in AMD environments are highly variable across sites. At Scalp Level Run in Summerset County PA, <span class="hlt">iron-oxidation</span> rates are five to eight times faster than other coal-associated AMD sites. We examined the microbial community at Scalp Level Run to determine whether a unique microbial community may be responsible for the observed rapid <span class="hlt">iron-oxidation</span> rates. Using MiSeq sequence tags, 16S rRNA gene clone libraries, and fluorescence in situ hybridization, we found that Scalp Level Run sediments host microbial populations closely related to the betaproteobacterium Ferritrophicum radicicola, an <span class="hlt">iron-oxidizing</span> species isolated from an acid mine drainage wetland in Virginia. Ferritrophicum spp. was not found at the four other coal-associated AMD sites in the study and is uncommon in the published literature. The influence of Ferritrophicum spp. populations in biogeochemical cycling, specifically their role in determining the <span class="hlt">iron-oxidation</span> rate at Scalp Level Run is unknown. Therefore, we employed metagenomic sequencing to examine the metabolic potential of the microbial community at Scalp Level Run.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22304546','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22304546"><span id="translatedtitle">Vapour phase approach for <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticle synthesis from solid precursors</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Singh, Mandeep; Ulbrich, Pavel; Prokopec, Vadym; Svoboda, Pavel; Šantavá, Eva; Štěpánek, František</p> <p>2013-04-15</p> <p>A new non-solution mediated approach to the synthesis of <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles directly from solid FeCl{sub 2} salt precursors has been developed. The method is rapid, simple and scalable. The structural properties and the phase of the resulting <span class="hlt">iron</span> <span class="hlt">oxide</span> particles has been determined by a range of methods including XRD, FT-IR and Mössbauer spectroscopy, and the phase is shown to be maghemite (γ-Fe{sub 2}O{sub 3}). The magnetic properties of the <span class="hlt">iron</span> <span class="hlt">oxide</span> particles have been measured using SQUID, confirming superparamagnetic behaviour of the powder and a saturation magnetization of 53.0 emu g{sup −1} at 300 K. Aqueous dispersions at increasing concentrations were prepared and their heating rate under a 400 kHz alternating magnetic field measured. The specific absorption rate (SAR) of the <span class="hlt">iron</span> <span class="hlt">oxide</span> was found to be 84.8 W g{sup −1}, which makes the material suitable for the formulation of ferrofluids or ferrogels with RF heating properties. - Graphical Abstract: Superparamagnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles obtained by a novel vapour phase approach. Highlights: ► Novel vapour phase (non-solvent) approach for <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticle synthesis. ► Attractive alternative approach to the present co-precipitation method. ► Better magnetic properties with high coercivity of nanoparticles. ► A high specific absorption rate (SAR) for hyperthermia applications.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_20 --> <div id="page_21" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22493174','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22493174"><span id="translatedtitle">Thin film lubrication of hexadecane confined by <span class="hlt">iron</span> and <span class="hlt">iron</span> <span class="hlt">oxide</span> surfaces: A crucial role of surface structure</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Ta, D. T.; Tieu, A. K.; Zhu, H. T. Kosasih, B.</p> <p>2015-10-28</p> <p>A comparative analysis of thin film lubrication of hexadecane between different <span class="hlt">iron</span> and its <span class="hlt">oxide</span> surfaces has been carried out using classical molecular dynamic simulation. An ab initio force-field, COMPASS, was applied for n-hexadecane using explicit atom model. An effective potential derived from density functional theory calculation was utilized for the interfacial interaction between hexadecane and the tribo-surfaces. A quantitative surface parameterization was introduced to investigate the influence of surface properties on the structure, rheological properties, and tribological performance of the lubricant. The results show that although the wall-fluid attraction of hexadecane on pure <span class="hlt">iron</span> surfaces is significantly stronger than its <span class="hlt">oxides</span>, there is a considerable reduction of shear stress of confined n-hexadecane film between Fe(100) and Fe(110) surfaces compared with FeO(110), FeO(111), Fe{sub 2}O{sub 3}(001), and Fe{sub 2}O{sub 3}(012). It was found that, in thin film lubrication of hexadecane between smooth <span class="hlt">iron</span> and <span class="hlt">iron</span> <span class="hlt">oxide</span> surfaces, the surface corrugation plays a role more important than the wall-fluid adhesion strength.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1044483','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1044483"><span id="translatedtitle">Size dependence of inter- and intra-cluster interactions in core-shell <span class="hlt">iron-iron</span> <span class="hlt">oxide</span> nanoclusters</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kaur, Maninder; McCloy, John S.; Jiang, Weilin; Yao, Qi; Qiang, You</p> <p>2012-06-15</p> <p>The room temperature magnetic properties of core-shell <span class="hlt">iron-iron</span> <span class="hlt">oxide</span> nanoclusters (NCs) synthesized by a cluster deposition system have been investigated, and their dependence on mean cluster size has been discussed. In this study, the surface/boundary spins of clusters were not frozen and were thermally activated during the measurements. The inter-cluster interactions between clusters and intra-cluster interactions between the <span class="hlt">iron</span> core (ferromagnetic) and <span class="hlt">iron</span> <span class="hlt">oxide</span> shell (ferrimagnetic) have been investigated by field dependent isothermal remanent magnetization and dc demagnetization measurements at room temperature. The Henkel plot and delta M plot support the existence of dipolar inter-cluster interactions which become stronger with the growth of cluster size. The derivative of the initial magnetization curve implies that smaller clusters require less field and time than the bigger ones to overcome various energy barriers before aligning along the field direction. Coercive field and magnetization are also correlated with the interaction parameters. To compare the room temperature magnetic results, one system was studied at low temperature, where exchange coupling at the interface between the <span class="hlt">oxide</span> and metallic phases was observed through bias effect and anisotropy enhancement.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/871100','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/871100"><span id="translatedtitle">Metal regeneration of <span class="hlt">iron</span> chelates in nitric <span class="hlt">oxide</span> scrubbing</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Chang, Shih-Ger; Littlejohn, David; Shi, Yao</p> <p>1997-08-19</p> <p>The present invention relates to a process of using metal particles to reduce NO to NH.sub.3. More specifically, the invention concerns an improved process to regenerate <span class="hlt">iron</span> (II) (CHELATE) by reduction of <span class="hlt">iron</span> (II) (CHELATE) (NO) complex, which process comprises: a) contacting an aqueous solution containing <span class="hlt">iron</span> (II) (CHELATE) (NO) with metal particles at between about 20.degree. and 90.degree. C. to reduce NO present, produce ammonia or an ammonium ion, and produce free <span class="hlt">iron</span> (II) (CHELATE) at a pH of between about 3 and 8. The process is useful to remove NO from flue gas and reduce pollution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/527767','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/biblio/527767"><span id="translatedtitle">Metal regeneration of <span class="hlt">iron</span> chelates in nitric <span class="hlt">oxide</span> scrubbing</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Chang, S.G.; Littlejohn, D.; Shi, Y.</p> <p>1997-08-19</p> <p>The present invention relates to a process of using metal particles to reduce NO to NH{sub 3}. More specifically, the invention concerns an improved process to regenerate <span class="hlt">iron</span> (II) (CHELATE) by reduction of <span class="hlt">iron</span> (II) (CHELATE) (NO) complex, which process comprises: (a) contacting an aqueous solution containing <span class="hlt">iron</span> (II) (CHELATE) (NO) with metal particles at between about 20 and 90 C to reduce NO present, produce ammonia or an ammonium ion, and produce free <span class="hlt">iron</span> (II) (CHELATE) at a pH of between about 3 and 8. The process is useful to remove NO from flue gas and reduce pollution. 34 figs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://medlineplus.gov/iron.html','NIH-MEDLINEPLUS'); return false;" href="https://medlineplus.gov/iron.html"><span id="translatedtitle"><span class="hlt">Iron</span></span></a></p> <p><a target="_blank" href="http://medlineplus.gov/">MedlinePlus</a></p> <p></p> <p></p> <p><span class="hlt">Iron</span> is a mineral that our bodies need for many functions. For example, <span class="hlt">iron</span> is part of hemoglobin, a protein which carries ... It helps our muscles store and use oxygen. <span class="hlt">Iron</span> is also part of many other proteins and ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/504878','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/504878"><span id="translatedtitle">Kinetics of reduction of <span class="hlt">iron</span> <span class="hlt">oxides</span> using microwaves as power source</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Gomez, I.; Aguilar, J.; Gonzalez, M.; Morales, J.</p> <p>1996-12-31</p> <p>This work deals with kinetic description of carbothermic reduction of <span class="hlt">iron</span> <span class="hlt">oxides</span> using microwaves as power source. Previous researches show that it is possible to conduct this kind of process successfully, but real kinetic comparisons between conventional and microwaves procedure have been presented partially. The aim of this work is to describe reduction kinetics, taking into account how the <span class="hlt">iron</span> <span class="hlt">oxide</span> is reduced by microwaves compared with conventional energy supply. In this study the authors used <span class="hlt">iron</span> ore in pellet shape and dust. They found that both, pellet and dust reduction stops when it reaches approximately 40%, even at whole power.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012PhDT.......135P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012PhDT.......135P"><span id="translatedtitle">Synthesis and characterization of platinum decorated <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles for biomedical applications</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Palchoudhury, Soubantika</p> <p></p> <p>This dissertation focuses on the development of a bifunctional nanoparticle system that can potentially offer simultaneous imaging and therapy in the future. Recently, small platinum (Pt) nanoparticles (< 5 nm) have shown great potential in therapeutic applications, such as DNA dissociation, radiation therapy, and <span class="hlt">oxidative</span> stress treatment. Therefore, the small Pt nanoparticles of size comparable to DNA grooves are chosen as potential therapeutic components in this research. However, such small sized Pt nanoparticles tends to aggregate, and are difficult to target. Therefore, this research reports the synthesis, characterization, and DNA interaction of small Pt decorated <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles. The <span class="hlt">iron</span> <span class="hlt">oxide</span> carriers provide stability to the small Pt nanoparticles, and can potentially serve as MRI contrast agents. The hypothesis of this research is that the Pt nanoparticles supported on <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticle surfaces can effectively interact with DNA molecules similar to the free Pt nanoparticles. A reproducible synthetic technique was first developed to prepare <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles with excellent size control and narrow size distribution. Subsequently, two different approaches were utilized to produce multiple small Pt nanoparticle attached <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles. The first route involved attachment of Pt nanoparticles onto <span class="hlt">iron</span> <span class="hlt">oxide</span> seeds of various shapes in an organic solvent, followed by an aqueous phase transfer. Here, the shape of the nanoparticles was controlled to facilitate heterogeneous nucleation of Pt nanoparticles. The protective biocompatible polymer coating (polyacrylic acid) in this method could prevent interaction of the Pt nanoparticles with undesirable biomolecules. Several non-spherical <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles were explored, including whiskers, worms, plates, and flowers. In the second method, an aqueous phase ligand exchange process was performed first, prior to the deposition of multiple Pt nanoparticles. This facile method</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17187443','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17187443"><span id="translatedtitle">Mineral and <span class="hlt">iron</span> <span class="hlt">oxidation</span> at low temperatures by pure and mixed cultures of acidophilic microorganisms.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Dopson, Mark; Halinen, Anna-Kaisa; Rahunen, Nelli; Ozkaya, Bestamin; Sahinkaya, Erkan; Kaksonen, Anna H; Lindström, E Börje; Puhakka, Jaakko A</p> <p>2007-08-01</p> <p>An enrichment culture from a boreal sulfide mine environment containing a low-grade polymetallic ore was tested in column bioreactors for simulation of low temperature heap leaching. PCR-denaturing gradient gel electrophoresis and 16S rRNA gene sequencing revealed the enrichment culture contained an Acidithiobacillus ferrooxidans strain with high 16S rRNA gene similarity to the psychrotolerant strain SS3 and a mesophilic Leptospirillum ferrooxidans strain. As the mixed culture contained a strain that was within a clade with SS3, we used the SS3 pure culture to compare leaching rates with the At. ferrooxidans type strain in stirred tank reactors for mineral sulfide dissolution at various temperatures. The psychrotolerant strain SS3 catalyzed pyrite, pyrite/arsenopyrite, and chalcopyrite concentrate leaching. The rates were lower at 5 degrees C than at 30 degrees C, despite that all the available <span class="hlt">iron</span> was in the <span class="hlt">oxidized</span> form in the presence of At. ferrooxidans SS3. This suggests that although efficient At. ferrooxidans SS3 mediated biological <span class="hlt">oxidation</span> of ferrous <span class="hlt">iron</span> occurred, chemical <span class="hlt">oxidation</span> of the sulfide minerals by ferric <span class="hlt">iron</span> was rate limiting. In the column reactors, the leaching rates were much less affected by low temperatures than in the stirred tank reactors. A factor for the relatively high rates of mineral <span class="hlt">oxidation</span> at 7 degrees C is that ferric <span class="hlt">iron</span> remained in the soluble phase whereas, at 21 degrees C the ferric <span class="hlt">iron</span> precipitated. Temperature gradient analysis of ferrous <span class="hlt">iron</span> <span class="hlt">oxidation</span> by this enrichment culture demonstrated two temperature optima for ferrous <span class="hlt">iron</span> <span class="hlt">oxidation</span> and that the mixed culture was capable of ferrous <span class="hlt">iron</span> <span class="hlt">oxidation</span> at 5 degrees C.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4199407','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4199407"><span id="translatedtitle">Taurine supplementation reduces <span class="hlt">oxidative</span> stress and protects the liver in an <span class="hlt">iron</span>-overload murine model</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>ZHANG, ZEYU; LIU, DAN; YI, BO; LIAO, ZHANGPING; TANG, LEI; YIN, DONG; HE, MING</p> <p>2014-01-01</p> <p>We previously demonstrated that <span class="hlt">iron</span> overload induces liver damage by causing the formation of reactive oxygen species (ROS). Taurine is a potent free radical scavenger that attenuates the damage caused by excessive oxygen free radicals. Therefore, the aim of the present study was to investigate whether taurine could reduce the hepatotoxicity of <span class="hlt">iron</span> overload with regard to ROS production. Mice were intraperitoneally injected with <span class="hlt">iron</span> 5 days/week for 13 weeks to achieve <span class="hlt">iron</span> overload. It was found that <span class="hlt">iron</span> overload resulted in liver dysfunction, increased apoptosis and elevated <span class="hlt">oxidative</span> stress. Taurine supplementation increased liver taurine levels by 40% and led to improved liver function, as well as a reduction in apoptosis, ROS formation and mitochondrial swelling and an attenuation in the loss of the mitochondrial membrane potential. Treatment with taurine mediated a reduction in <span class="hlt">oxidative</span> stress in <span class="hlt">iron</span>-overloaded mice, attenuated liver lipid peroxidation, elevated antioxidant enzyme activities and maintained reduced glutathione levels. These results indicate that taurine reduces <span class="hlt">iron</span>-induced hepatic <span class="hlt">oxidative</span> stress, preserves liver function and inhibits hepatocyte apoptosis. Therefore, taurine may be a potential therapeutic drug to reduce liver damage caused by <span class="hlt">iron</span> overload. PMID:25201602</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/18215735','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/18215735"><span id="translatedtitle"><span class="hlt">Iron</span> chelators can protect against <span class="hlt">oxidative</span> stress through ferryl heme reduction.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Reeder, Brandon J; Hider, Robert C; Wilson, Michael T</p> <p>2008-02-01</p> <p><span class="hlt">Iron</span> chelators such as desferrioxamine have been shown to ameliorate <span class="hlt">oxidative</span> damage in vivo. The mechanism of this therapeutic action under non-<span class="hlt">iron</span>-overload conditions is, however, complex, as desferrioxamine has properties that can impact on <span class="hlt">oxidative</span> damage independent of its capacity to act as an <span class="hlt">iron</span> chelator. Desferrioxamine can act as a reducing agent to remove cytotoxic ferryl myoglobin and hemoglobin and has recently been shown to prevent the formation of a highly cytotoxic heme-to-protein cross-linked derivative of myoglobin. In this study we have examined the effects of a wide range of <span class="hlt">iron</span> chelators, including the clinically used hydroxypyridinone CP20 (deferriprone), on the stability of ferryl myoglobin and on the formation of heme-to-protein cross-linking. We show that all hydroxypyridinones, as well as many other <span class="hlt">iron</span> chelators, are efficient reducing agents of ferryl myoglobin. These compounds are also effective at preventing the formation of cytotoxic derivatives of myoglobin such as heme-to-protein cross-linking. These results show that the use of <span class="hlt">iron</span> chelators in vivo may ameliorate <span class="hlt">oxidative</span> damage under conditions of non-<span class="hlt">iron</span> overload by at least two mechanisms. The antioxidant effects of chelators in vivo cannot, therefore, be attributed solely to <span class="hlt">iron</span> chelation. PMID:18215735</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1211208','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1211208"><span id="translatedtitle">Size- and Composition-Dependent Radio Frequency Magnetic Permeability of <span class="hlt">Iron</span> <span class="hlt">Oxide</span> Nanocrystals</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Yun, H; Liu, XY; Paik, T; Palanisamy, D; Kim, J; Vogel, WD; Viescas, AJ; Chen, J; Papaefthymiou, GC; Kikkawa, JM; Allen, MG; Murray, CB</p> <p>2014-12-01</p> <p>We investigate the size- and composition-dependent ac magnetic permeability of superparamagnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> nanocrystals for radio frequency (RF) applications. The nanocrystals are obtained through high-temperature decomposition synthesis, and their stoichiometry is determined by Mossbauer spectroscopy. Two sets of <span class="hlt">oxides</span> are studied: (a) as-synthesized magnetite-rich and (b) aged maghemite nanocrystals. All nanocrystalline samples are confirmed to be in the superparamagnetic state at room temperature by SQUID magnetometry. Through the one-turn inductor method, the ac magnetic properties of the nanocrystalline <span class="hlt">oxides</span> are characterized. In magnetite-rich <span class="hlt">iron</span> <span class="hlt">oxide</span> nanocrystals, size-dependent magnetic permeability is not observed, while maghemite <span class="hlt">iron</span> <span class="hlt">oxide</span> nanocrystals show clear size dependence. The inductance, resistance, and quality factor of hand-wound inductors with a superparamagnetic composite core are measured. The superparamagnetic nanocrystals are successfully embedded into hand-wound inductors to function as inductor cores.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25390073','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25390073"><span id="translatedtitle">Size- and composition-dependent radio frequency magnetic permeability of <span class="hlt">iron</span> <span class="hlt">oxide</span> nanocrystals.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yun, Hongseok; Liu, Xiyu; Paik, Taejong; Palanisamy, Duraivelan; Kim, Jungkwun; Vogel, William D; Viescas, Arthur J; Chen, Jun; Papaefthymiou, Georgia C; Kikkawa, James M; Allen, Mark G; Murray, Christopher B</p> <p>2014-12-23</p> <p>We investigate the size- and composition-dependent ac magnetic permeability of superparamagnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> nanocrystals for radio frequency (RF) applications. The nanocrystals are obtained through high-temperature decomposition synthesis, and their stoichiometry is determined by Mössbauer spectroscopy. Two sets of <span class="hlt">oxides</span> are studied: (a) as-synthesized magnetite-rich and (b) aged maghemite nanocrystals. All nanocrystalline samples are confirmed to be in the superparamagnetic state at room temperature by SQUID magnetometry. Through the one-turn inductor method, the ac magnetic properties of the nanocrystalline <span class="hlt">oxides</span> are characterized. In magnetite-rich <span class="hlt">iron</span> <span class="hlt">oxide</span> nanocrystals, size-dependent magnetic permeability is not observed, while maghemite <span class="hlt">iron</span> <span class="hlt">oxide</span> nanocrystals show clear size dependence. The inductance, resistance, and quality factor of hand-wound inductors with a superparamagnetic composite core are measured. The superparamagnetic nanocrystals are successfully embedded into hand-wound inductors to function as inductor cores.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5770040','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5770040"><span id="translatedtitle"><span class="hlt">Iron</span>-tellurium-selenium mixed <span class="hlt">oxide</span> catalysts for the selective <span class="hlt">oxidation</span> of propylene to acrolein</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Patel, B.M.; Price, G.L. )</p> <p>1990-05-01</p> <p>This paper reports on <span class="hlt">iron</span>-tellurium-selenium mixed <span class="hlt">oxide</span> catalysts prepared by coprecipitation from aqueous solution investigated for the propylene to acrolein reaction in the temperature range 543-773 K. Infrared spectroscopy, electron dispersive X-ray analysis, X-ray diffraction, and isotopic tracer techniques have also been employed to characterize this catalytic system. Properties of the Fe-Te-Se mixed <span class="hlt">oxide</span> catalysts have been compared with Fe-Te mixed <span class="hlt">oxides</span> in an effort to deduce the functionality of Se. The selenium in the Fe-Te-Se-O catalyst has been found to be the hydrocarbon activating site. The activation energies for the acrolein and carbon dioxide formation are 71 and 54 kJ/mol, respectively. Reactions carried out with {sup 18}O{sub 2} have shown lattice oxygen to be primarily responsible for the formation of both acrolein and carbon dioxide. The initial and rate-determining step for acrolein formation is hydrogen abstraction as determined by an isotope effect associated with the C{sub 3}D{sub 6} reaction. No isotope effect is observed for carbon dioxide formation from C{sub 3}D{sub 6} suggesting that CO{sub 2} is formed by parallel, not consecutive, <span class="hlt">oxidation</span> of propylene.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4038746','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4038746"><span id="translatedtitle">Interactions of proteins with biogenic <span class="hlt">iron</span> oxyhydroxides and a new culturing technique to increase biomass yields of neutrophilic, <span class="hlt">iron-oxidizing</span> bacteria</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Barco, Roman A.; Edwards, Katrina J.</p> <p>2014-01-01</p> <p>Neutrophilic, bacterial <span class="hlt">iron-oxidation</span> remains one of the least understood energy-generating biological reactions to date. One of the reasons it remains under-studied is because there are inherent problems with working with <span class="hlt">iron-oxidizing</span> bacteria (FeOB), including low biomass yields and interference from the <span class="hlt">iron</span> <span class="hlt">oxides</span> in the samples. In an effort to circumvent the problem of low biomass, a new large batch culturing technique was developed. Protein interactions with biogenic <span class="hlt">iron</span> <span class="hlt">oxides</span> were investigated confirming that such interactions are strong. Therefore, a protein extraction method is described to minimize binding of proteins to biogenic <span class="hlt">iron</span> <span class="hlt">oxides</span>. The combination of these two methods results in protein yields that are appropriate for activity assays in gels and for proteomic profiling. PMID:24910632</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3364526','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3364526"><span id="translatedtitle">Microbial <span class="hlt">Iron</span>(II) <span class="hlt">Oxidation</span> in Littoral Freshwater Lake Sediment: The Potential for Competition between Phototrophic vs. Nitrate-Reducing <span class="hlt">Iron(II)-Oxidizers</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Melton, E. D.; Schmidt, C.; Kappler, A.</p> <p>2012-01-01</p> <p>The distribution of neutrophilic microbial <span class="hlt">iron</span> <span class="hlt">oxidation</span> is mainly determined by local gradients of oxygen, light, nitrate and ferrous <span class="hlt">iron</span>. In the anoxic top part of littoral freshwater lake sediment, nitrate-reducing and phototrophic Fe(II)-<span class="hlt">oxidizers</span> compete for the same e− donor; reduced <span class="hlt">iron</span>. It is not yet understood how these microbes co-exist in the sediment and what role they play in the Fe cycle. We show that both metabolic types of anaerobic Fe(II)-<span class="hlt">oxidizing</span> microorganisms are present in the same sediment layer directly beneath the oxic-anoxic sediment interface. The photoferrotrophic most probable number counted 3.4·105 cells·g−1 and the autotrophic and mixotrophic nitrate-reducing Fe(II)-<span class="hlt">oxidizers</span> totaled 1.8·104 and 4.5·104 cells·g−1 dry weight sediment, respectively. To distinguish between the two microbial Fe(II) <span class="hlt">oxidation</span> processes and assess their individual contribution to the sedimentary Fe cycle, littoral lake sediment was incubated in microcosm experiments. Nitrate-reducing Fe(II)-<span class="hlt">oxidizing</span> bacteria exhibited a higher maximum Fe(II) <span class="hlt">oxidation</span> rate per cell, in both pure cultures and microcosms, than photoferrotrophs. In microcosms, photoferrotrophs instantly started <span class="hlt">oxidizing</span> Fe(II), whilst nitrate-reducing Fe(II)-<span class="hlt">oxidizers</span> showed a significant lag-phase during which they probably use organics as e− donor before initiating Fe(II) <span class="hlt">oxidation</span>. This suggests that they will be outcompeted by phototrophic Fe(II)-<span class="hlt">oxidizers</span> during optimal light conditions; as phototrophs deplete Fe(II) before nitrate-reducing Fe(II)-<span class="hlt">oxidizers</span> start Fe(II) <span class="hlt">oxidation</span>. Thus, the co-existence of the two anaerobic Fe(II)-<span class="hlt">oxidizers</span> may be possible due to a niche space separation in time by the day-night cycle, where nitrate-reducing Fe(II)-<span class="hlt">oxidizers</span> <span class="hlt">oxidize</span> Fe(II) during darkness and phototrophs play a dominant role in Fe(II) <span class="hlt">oxidation</span> during daylight. Furthermore, metabolic flexibility of Fe(II)-<span class="hlt">oxidizing</span> microbes may play a paramount role in the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=105055&keyword=oxygen+AND+essential&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=78984405&CFTOKEN=97709697','EPA-EIMS'); return false;" href="http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=105055&keyword=oxygen+AND+essential&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=78984405&CFTOKEN=97709697"><span id="translatedtitle">THE <span class="hlt">IRON</span> CYCLE AND <span class="hlt">OXIDATIVE</span> STRESS IN THE LUNG</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>While <span class="hlt">iron</span> is essential for many aspects of cellular function, it can also generate oxygen-based free radicals that result in injury to biological molecules. For this reason, <span class="hlt">iron</span> acquisition and distribution must be tightly regulated. Constant exposure to the atmosphere, howev...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26817529','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26817529"><span id="translatedtitle">The responses of immune cells to <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Xu, Yaolin; Sherwood, Jennifer A; Lackey, Kimberly H; Qin, Ying; Bao, Yuping</p> <p>2016-04-01</p> <p>Immune cells play an important role in recognizing and removing foreign objects, such as nanoparticles. Among various parameters, surface coatings of nanoparticles are the first contact with biological system, which critically affect nanoparticle interactions. Here, surface coating effects on nanoparticle cellular uptake, toxicity and ability to trigger immune response were evaluated on a human monocyte cell line using <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles. The cells were treated with nanoparticles of three types of coatings (negatively charged polyacrylic acid, positively charged polyethylenimine and neutral polyethylene glycol). The cells were treated at various nanoparticle concentrations (5, 10, 20, 30, 50 μg ml(-1) or 2, 4, 8, 12, 20 μg cm(-2)) with 6 h incubation or treated at a nanoparticle concentration of 50 μg ml(-1) (20 μg cm(-2)) at different incubation times (6, 12, 24, 48 or 72 h). Cell viability over 80% was observed for all nanoparticle treatment experiments, regardless of surface coatings, nanoparticle concentrations and incubation times. The much lower cell viability for cells treated with free ligands (e.g. ~10% for polyethylenimine) suggested that the surface coatings were tightly attached to the nanoparticle surfaces. The immune responses of cells to nanoparticles were evaluated by quantifying the expression of toll-like receptor 2 and tumor necrosis factor-α. The expression of tumor necrosis factor-α and toll-like receptor 2 were not significant in any case of the surface coatings, nanoparticle concentrations and incubation times. These results provide useful information to select nanoparticle surface coatings for biological and biomedical applications. PMID:26817529</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4367499','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4367499"><span id="translatedtitle">Physicochemical Characterization of Nebulized Superparamagnetic <span class="hlt">Iron</span> <span class="hlt">Oxide</span> Nanoparticles (SPIONs)</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Graczyk, Halshka; Bryan, Louise C.; Lewinski, Nastassja; Suarez, Guillaume; Coullerez, Geraldine; Bowen, Paul</p> <p>2015-01-01</p> <p>Abstract Background: Aerosol-mediated delivery of nano-based therapeutics to the lung has emerged as a promising alternative for treatment and prevention of lung diseases. Superparamagnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles (SPIONs) have attracted significant attention for such applications due to their biocompatibility and magnetic properties. However, information is lacking about the characteristics of nebulized SPIONs for use as a therapeutic aerosol. To address this need, we conducted a physicochemical characterization of nebulized Rienso, a SPION-based formulation for intravenous treatment of anemia. Methods: Four different concentrations of SPION suspensions were nebulized with a one-jet nebulizer. Particle size was measured in suspension by transmission electron microscopy (TEM), photon correlation spectroscopy (PCS), and nanoparticle tracking analysis (NTA), and in the aerosol by a scanning mobility particle sizer (SMPS). Results: The average particle size in suspension as measured by TEM, PCS, and NTA was 9±2 nm, 27±7 nm, and 56±10 nm, respectively. The particle size in suspension remained the same before and after the nebulization process. However, after aerosol collection in an impinger, the suspended particle size increased to 159±46 nm as measured by NTA. The aerosol particle concentration increased linearly with increasing suspension concentration, and the aerodynamic diameter remained relatively stable at around 75 nm as measured by SMPS. Conclusions: We demonstrated that the total number and particle size in the aerosol were modulated as a function of the initial concentration in the nebulizer. The data obtained mark the first known independent characterization of nebulized Rienso and, as such, provide critical information on the behavior of Rienso nanoparticles in an aerosol. The data obtained in this study add new knowledge to the existing body of literature on potential applications of SPION suspensions as inhaled aerosol therapeutics. PMID</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009SPIE.7181E..0OC','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009SPIE.7181E..0OC"><span id="translatedtitle"><span class="hlt">Iron</span> <span class="hlt">oxide</span> nanoparticle hyperthermia and radiation cancer treatment</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cassim, S. M.; Giustini, A. J.; Petryk, A. A.; Strawbridge, R. A.; Hoopes, P. J.</p> <p>2009-02-01</p> <p>It is established that heat can enhance the effect of radiation cancer treatment. Due to the ability to localize thermal energy using nanoparticle hyperthermia, as opposed to other, less targeted, hyperthermia modalities, it appears such enhancement could be accomplished without complications normally associated with systemic or regional hyperthermia. This study employs non-curative (suboptimal), doses of heat and radiation, in an effort to determine the therapeutic enhancement potential for IONP hyperthermia and radiation. Methods: MTG-B murine breast adenocarcinoma cell are inoculated into the right flanks of female CH3/HEJ mice and grown to volumes of 150mm3+ /- 40 mm3. A single dose of 15 Gy (6 MeV) radiation was uniformly delivered to the tumor. A pre-defined thermal dose is delivered by direct injection of <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles into the tumor. By adjusting the field strength of the 160 KHz alternating magnetic field (AMF) an intra-tumoral temperature between 41.5 and 43 degrees Celsius was maintained for 10min. The alternating magnetic field was delivered by a water-cooled 36mm diameter square copper tube induction coil operating at 160 kHz with variable magnet field strengths up to 450 Oe . The primary endpoint of the study is the number of days required for the tumor to achieve a volume 3 fold greater than the volume at the time of treatment (tumor regrowth delay). Results: Preliminary results suggest the addition of a modest IONP hyperthermia to 15 Gy radiation achieved an approximate 50% increase in tumor regrowth delay as compared to a 15 Gy radiation treatment alone. The therapeutic effects of IONP heat and radiation combined were considered additive, however in mice that demonstrated complete response (no tumor present after 30 days), the effect was considered superadditive or synergistic. Although this data is very encouraging from a multimodality cancer therapy standpoint, additional temporal and dose related information is clearly necessary to</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1007864','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1007864"><span id="translatedtitle">Mechanisms of <span class="hlt">iron</span> <span class="hlt">oxide</span> transformation in hydrothermal systems.</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Otake, Tsubasa; Wesolowski, David J; Anovitz, Lawrence {Larry} M</p> <p>2010-11-01</p> <p>Coexistence of magnetite and hematite in hydrothermal systems has often been used to constrain the redox potential of fluids, assuming that the redox equilibrium is attained among all minerals and aqueous species. However, as temperature decreases, disequilibrium mineral assemblages may occur due to the slow kinetics of reaction involving the minerals and fluids. In this study, we conducted a series of experiments in which hematite or magnetite was reacted with an acidic solution under H{sub 2}-rich hydrothermal conditions (T = 100-250 C, P{sub H{sub 2}} = 0.05-5 MPa) to investigate the kinetics of redox and non-redox transformations between hematite and magnetite, and the mechanisms of <span class="hlt">iron</span> <span class="hlt">oxide</span> transformation under hydrothermal conditions. The formation of euhedral crystals of hematite in 150 and 200 C experiments, in which magnetite was used as the starting material, indicates that non-redox transformation of magnetite to hematite occurred within 24 h. The chemical composition of the experimental solutions was controlled by the non-redox transformation between magnetite and hematite throughout the experiments. While solution compositions were controlled by the non-redox transformation in the first 3 days in a 250 C experiment, reductive dissolution of magnetite became important after 5 days and affected the solution chemistry. At 100 C, the presence of maghemite was indicated in the first 7 days. Based on these results, equilibrium constants of non-redox transformation between magnetite and hematite and those of non-redox transformation between magnetite and maghemite were calculated. Our results suggest that the redox transformation of hematite to magnetite occurs in the following steps: (1) reductive dissolution of hematite to Fe{sub (aq)}{sup 2+} and (2) non-redox transformation of hematite and Fe{sub (aq)}{sup 2+} to magnetite.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_21 --> <div id="page_22" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="421"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1021991','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1021991"><span id="translatedtitle">Mechanisms of <span class="hlt">iron</span> <span class="hlt">oxide</span> transformations in hydrothermal systems.</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Otake, Tsubasa; Wesolowski, David J; Anovitz, Lawrence {Larry} M; Allard Jr, Lawrence Frederick; Ohmoto, Hiroshi</p> <p>2010-01-01</p> <p>Coexistence of magnetite and hematite in hydrothermal systems has often been used to constrain the redox potential of fluids, assuming that the redox equilibrium is attained among all minerals and aqueous species. However, as temperature decreases, disequilibrium mineral assemblages may occur due to the slow kinetics of reaction involving the minerals and fluids. In this study, we conducted a series of experiments in which hematite or magnetite was reacted with an acidic solution under H2-rich hydrothermal conditions (T = 100 250 C,) to investigate the kinetics of redox and non-redox transformations between hematite and magnetite, and the mechanisms of <span class="hlt">iron</span> <span class="hlt">oxide</span> transformation under hydrothermal conditions. The formation of euhedral crystals of hematite in 150 and 200 C experiments, in which magnetite was used as the starting material, indicates that non-redox transformation of magnetite to hematite occurred within 24 h. The chemical composition of the experimental solutions was controlled by the non-redox transformation between magnetite and hematite throughout the experiments. While solution compositions were controlled by the non-redox transformation in the first 3 days in a 250 C experiment, reductive dissolution of magnetite became important after 5 days and affected the solution chemistry. At 100 C, the presence of maghemite was indicated in the first 7 days. Based on these results, equilibrium constants of non-redox transformation between magnetite and hematite and those of non-redox transformation between magnetite and maghemite were calculated. Our results suggest that the redox transformation of hematite to magnetite occurs in the following steps: (1) reductive dissolution of hematite to and (2) non-redox transformation of hematite and to magnetite.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26057456','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26057456"><span id="translatedtitle">Surface Functionalization of <span class="hlt">Oxide</span>-Covered Zinc and <span class="hlt">Iron</span> with Phosphonated Phenylethynyl Phenothiazine.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Rechmann, Julian; Sarfraz, Adnan; Götzinger, Alissa C; Dirksen, Elena; Müller, Thomas J J; Erbe, Andreas</p> <p>2015-07-01</p> <p>Phenothiazines are redox-active, fluorescent molecules with potential applications in molecular electronics. Phosphonated phenylethynyl phenothiazine can be easily obtained in a four-step synthesis, yielding a molecule with a headgroup permitting surface linkage. Upon modifying hydroxylated polycrystalline zinc and <span class="hlt">iron</span>, both covered with their respective native <span class="hlt">oxides</span>, ultrathin organic layers were formed and investigated by use of infrared (IR) reflection spectroscopy, X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS), contact angle measurement, and ellipsometry. While stable monolayers with upright oriented organic molecules were formed on <span class="hlt">oxide</span>-covered <span class="hlt">iron</span>, multilayer formation is observed on <span class="hlt">oxide</span>-covered zinc. ToF-SIMS measurements reveal a bridging bidentate bonding state of the organic compound on <span class="hlt">oxide</span>-covered <span class="hlt">iron</span>, whereas monodentate complexes were observed on <span class="hlt">oxide</span>-covered zinc. Both organically modified and unmodified surfaces exhibit reactive wetting, but organic modification makes the surfaces initially more hydrophobic. Cyclic voltammetry (CV) indicates redox activity of the multilayers formed on <span class="hlt">oxide</span>-covered zinc. On the other hand, the monolayers on <span class="hlt">oxide</span>-covered <span class="hlt">iron</span> desorb after electrochemical modifications in the state of the <span class="hlt">oxide</span>, but are stable at open circuit conditions. Exploiting an electronic coupling of phenothiazines to <span class="hlt">oxides</span> may thus assist in corrosion protection.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AGUFM.B33A0844C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AGUFM.B33A0844C"><span id="translatedtitle"><span class="hlt">Iron</span> <span class="hlt">oxidation</span> and biomineralization by Mariprofundus ferrooxydans, a deep-sea microaerophilic lithoautotroph</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chan, C. S.; Emerson, D.; Fakra, S.; Edwards, K. J.</p> <p>2007-12-01</p> <p>The ocean crust contains a large reservoir of reduced <span class="hlt">iron</span>, available for microbial energy generation. Some of this ferrous <span class="hlt">iron</span> is mobilized by fluids in hydrothermal fields at seamounts and mid-ocean ridges. A microaerophilic <span class="hlt">iron</span> <span class="hlt">oxidizer</span>, Mariprofundus ferrooxydans has been identified (by molecular methods and microscopy) at various sites, and appears to be a key <span class="hlt">iron-oxidizing</span> bacterium (FeOB) in the deep sea. Originally isolated from microbial mats near vents at the Loihi Seamount in Hawaii, Mariprofundus is distinctive because it forms an extracellular <span class="hlt">iron</span>-mineralized stalk-like structure. We aim to understand its metabolism and mineral formation using a multidisciplinary approach, including electron microscopy, x-ray spectroscopy, time-lapse light microscopic imaging of live cells, and genomic and biochemical analyses. Microscopy and spectroscopy work shows that as the cells grow, they excretes <span class="hlt">iron</span> and organic-rich fibrils that make up the stalk, at a rate of ~2 microns/hr. Stalk growth appears to be parallel to the direction of Fe and oxygen gradients. The Mariprofundus genome contains several terminal oxidases/peroxidases, including two cbb3-type cytochrome oxidases with a high affinity for oxygen, consistent with the microaerophilic lifestyle of these organisms. However, we have not identified genes for metabolisms other than aerobic <span class="hlt">iron</span> <span class="hlt">oxidation</span>, nor have we found any genes similar to known or suspected <span class="hlt">iron</span> oxidases, though the genome (2.87 Mb) is rich in cytochromes (32 of 2922 genes). Thus, we are performing experiments to extract and analyze proteins from both cultured and environmental samples in order to find ones that will <span class="hlt">oxidize</span> <span class="hlt">iron</span>. UV-Vis spectra of extracts suggest that c-type cytochromes are particularly abundant, so these are candidates for further investigation. In combination with the microscopy and spectroscopy studies, these are the first steps towards understanding the complete pathway of <span class="hlt">iron</span> from uptake through mineral</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22820746','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22820746"><span id="translatedtitle">Recovery of <span class="hlt">iron</span> <span class="hlt">oxides</span> from acid mine drainage and their application as adsorbent or catalyst.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Flores, Rubia Gomes; Andersen, Silvia Layara Floriani; Maia, Leonardo Kenji Komay; José, Humberto Jorge; Moreira, Regina de Fatima Peralta Muniz</p> <p>2012-11-30</p> <p><span class="hlt">Iron</span> <span class="hlt">oxide</span> particles recovered from acid mine drainage represent a potential low-cost feedstock to replace reagent-grade chemicals in the production of goethite, ferrihydrite or magnetite with relatively high purity. Also, the properties of <span class="hlt">iron</span> <span class="hlt">oxides</span> recovered from acid mine drainage mean that they can be exploited as catalysts and/or adsorbents to remove azo dyes from aqueous solutions. The main aim of this study was to recover <span class="hlt">iron</span> <span class="hlt">oxides</span> with relatively high purity from acid mine drainage to act as a catalyst in the <span class="hlt">oxidation</span> of dye through a Fenton-like mechanism or as an adsorbent to remove dyes from an aqueous solution. <span class="hlt">Iron</span> <span class="hlt">oxides</span> (goethite) were recovered from acid mine drainage through a sequential precipitation method. Thermal treatment at temperatures higher than 300 °C produces hematite through a decrease in the BET area and an increase in the point of zero charge. In the absence of hydrogen peroxide, the solids adsorbed the textile dye Procion Red H-E7B according to the Langmuir model, and the maximum amount adsorbed decreased as the temperature of the thermal treatment increased. The decomposition kinetics of hydrogen peroxide is dependent on the H(2)O(2) concentration and <span class="hlt">iron</span> <span class="hlt">oxides</span> dosage, but the second-order rate constant normalized to the BET surface area is similar to that for different <span class="hlt">iron</span> <span class="hlt">oxides</span> tested in this and others studies. These results indicate that acid mine drainage could be used as a source material for the production of <span class="hlt">iron</span> <span class="hlt">oxide</span> catalysts/adsorbents, with comparable quality to those produced using analytical-grade reagents.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26016610','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26016610"><span id="translatedtitle">N-butylamine functionalized graphene <span class="hlt">oxide</span> for detection of <span class="hlt">iron</span>(III) by photoluminescence quenching.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gholami, Javad; Manteghian, Mehrdad; Badiei, Alireza; Ueda, Hiroshi; Javanbakht, Mehran</p> <p>2016-02-01</p> <p>An N-butylamine functionalized graphene <span class="hlt">oxide</span> nanolayer was synthesized and characterized by ultraviolet (UV)-visible spectrometry, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy. Detection of <span class="hlt">iron</span>(III) based on photoluminescence spectroscopy was investigated. The N-butylamine functionalized graphene <span class="hlt">oxide</span> was shown to specifically interact with <span class="hlt">iron</span> (III), compared with other cationic trace elements including potassium (I), sodium (I), calcium (II), chromium (III), zinc (II), cobalt (II), copper (II), magnesium (II), manganese (II), and molybdenum (VI). The quenching effect of <span class="hlt">iron</span> (III) on the luminescence emission of N-butylamine functionalized graphene <span class="hlt">oxide</span> layer was used to detect <span class="hlt">iron</span> (III). The limit of detection (2.8 × 10(-6)  M) and limit of quantitation (2.9 × 10(-5)  M) were obtained under optimal conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4620901','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4620901"><span id="translatedtitle">Bubble nucleation and migration in a lead–<span class="hlt">iron</span> hydr(<span class="hlt">oxide</span>) core–shell nanoparticle</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Niu, Kaiyang; Frolov, Timofey; Xin, Huolin L.; Wang, Junling; Asta, Mark; Zheng, Haimei</p> <p>2015-01-01</p> <p><span class="hlt">Iron</span> hydroxide is found in a wide range of contexts ranging from biominerals to steel corrosion, and it can transform to anhydrous <span class="hlt">oxide</span> via releasing O2 gas and H2O. However, it is not well understood how gases transport through a crystal lattice. Here, we present in situ observation of the nucleation and migration of gas bubbles in <span class="hlt">iron</span> (hydr)<span class="hlt">oxide</span> using transmission electron microscopy. We create Pb–FeOOH model core–shell nanoparticles in a liquid cell. Under electron irradiation, <span class="hlt">iron</span> hydroxide transforms to <span class="hlt">iron</span> <span class="hlt">oxide</span>, during which bubbles are generated, and they migrate through the shell to the nanoparticle surface. Geometric phase analysis of the shell lattice shows an inhomogeneous stain field at the bubbles. Our modeling suggests that the elastic interaction between the core and the bubble provides a driving force for bubble migration. PMID:26438864</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26016610','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26016610"><span id="translatedtitle">N-butylamine functionalized graphene <span class="hlt">oxide</span> for detection of <span class="hlt">iron</span>(III) by photoluminescence quenching.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gholami, Javad; Manteghian, Mehrdad; Badiei, Alireza; Ueda, Hiroshi; Javanbakht, Mehran</p> <p>2016-02-01</p> <p>An N-butylamine functionalized graphene <span class="hlt">oxide</span> nanolayer was synthesized and characterized by ultraviolet (UV)-visible spectrometry, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy. Detection of <span class="hlt">iron</span>(III) based on photoluminescence spectroscopy was investigated. The N-butylamine functionalized graphene <span class="hlt">oxide</span> was shown to specifically interact with <span class="hlt">iron</span> (III), compared with other cationic trace elements including potassium (I), sodium (I), calcium (II), chromium (III), zinc (II), cobalt (II), copper (II), magnesium (II), manganese (II), and molybdenum (VI). The quenching effect of <span class="hlt">iron</span> (III) on the luminescence emission of N-butylamine functionalized graphene <span class="hlt">oxide</span> layer was used to detect <span class="hlt">iron</span> (III). The limit of detection (2.8 × 10(-6)  M) and limit of quantitation (2.9 × 10(-5)  M) were obtained under optimal conditions. PMID:26016610</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22488970','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22488970"><span id="translatedtitle">Shape control of the magnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles under different chain length of reducing agents</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Ngoi, Kuan Hoon; Chia, Chin-Hua Zakaria, Sarani; Chiu, Wee Siong</p> <p>2015-09-25</p> <p>We report on the effect of using reducing agents with different chain-length on the synthesis of <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles by thermal decomposition of <span class="hlt">iron</span> (III) acetylacetonate in 1-octadecene. This modification allows us to control the shape of nanoparticles into spherical and cubic <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles. The highly monodisperse 14 nm spherical nanoparticles are obtained under 1,2-dodecanediol and average 14 nm edge-length cubic <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles are obtained under 1,2-tetradecanediol. The structural characterization such as transmission electron microscope (TEM) and X-ray diffraction (XRD) shows similar properties between two particles with different shapes. The vibrating sample magnetometer (VSM) shows no significant difference between spherical and cubic nanoparticles, which are 36 emu/g and 37 emu/g respectively and superparamagnetic in nature.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4651080','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4651080"><span id="translatedtitle">Microbial <span class="hlt">Iron</span> <span class="hlt">Oxidation</span> in the Arctic Tundra and Its Implications for Biogeochemical Cycling</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Scott, Jarrod J.; Benes, Joshua; Bowden, William B.</p> <p>2015-01-01</p> <p>The role that neutrophilic <span class="hlt">iron-oxidizing</span> bacteria play in the Arctic tundra is unknown. This study surveyed chemosynthetic <span class="hlt">iron-oxidizing</span> communities at the North Slope of Alaska near Toolik Field Station (TFS) at Toolik Lake (lat 68.63, long −149.60). Microbial <span class="hlt">iron</span> mats were common in submerged habitats with stationary or slowly flowing water, and their greatest areal extent is in coating plant stems and sediments in wet sedge meadows. Some Fe-<span class="hlt">oxidizing</span> bacteria (FeOB) produce easily recognized sheath or stalk morphotypes that were present and dominant in all the mats we observed. The cool water temperatures (9 to 11°C) and reduced pH (5.0 to 6.6) at all sites kinetically favor microbial <span class="hlt">iron</span> <span class="hlt">oxidation</span>. A microbial survey of five sites based on 16S rRNA genes found a predominance of Proteobacteria, with Betaproteobacteria and members of the family Comamonadaceae being the most prevalent operational taxonomic units (OTUs). In relative abundance, clades of lithotrophic FeOB composed 5 to 10% of the communities. OTUs related to cyanobacteria and chloroplasts accounted for 3 to 25% of the communities. Oxygen profiles showed evidence for oxygenic photosynthesis at the surface of some mats, indicating the coexistence of photosynthetic and FeOB populations. The relative abundance of OTUs belonging to putative Fe-reducing bacteria (FeRB) averaged around 11% in the sampled <span class="hlt">iron</span> mats. Mats incubated anaerobically with 10 mM acetate rapidly initiated Fe reduction, indicating that active <span class="hlt">iron</span> cycling is likely. The prevalence of <span class="hlt">iron</span> mats on the tundra might impact the carbon cycle through lithoautotrophic chemosynthesis, anaerobic respiration of organic carbon coupled to <span class="hlt">iron</span> reduction, and the suppression of methanogenesis, and it potentially influences phosphorus dynamics through the adsorption of phosphorus to <span class="hlt">iron</span> <span class="hlt">oxides</span>. PMID:26386054</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26386054','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26386054"><span id="translatedtitle">Microbial <span class="hlt">iron</span> <span class="hlt">oxidation</span> in the Arctic tundra and its implications for biogeochemical cycling.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Emerson, David; Scott, Jarrod J; Benes, Joshua; Bowden, William B</p> <p>2015-12-01</p> <p>The role that neutrophilic <span class="hlt">iron-oxidizing</span> bacteria play in the Arctic tundra is unknown. This study surveyed chemosynthetic <span class="hlt">iron-oxidizing</span> communities at the North Slope of Alaska near Toolik Field Station (TFS) at Toolik Lake (lat 68.63, long -149.60). Microbial <span class="hlt">iron</span> mats were common in submerged habitats with stationary or slowly flowing water, and their greatest areal extent is in coating plant stems and sediments in wet sedge meadows. Some Fe-<span class="hlt">oxidizing</span> bacteria (FeOB) produce easily recognized sheath or stalk morphotypes that were present and dominant in all the mats we observed. The cool water temperatures (9 to 11°C) and reduced pH (5.0 to 6.6) at all sites kinetically favor microbial <span class="hlt">iron</span> <span class="hlt">oxidation</span>. A microbial survey of five sites based on 16S rRNA genes found a predominance of Proteobacteria, with Betaproteobacteria and members of the family Comamonadaceae being the most prevalent operational taxonomic units (OTUs). In relative abundance, clades of lithotrophic FeOB composed 5 to 10% of the communities. OTUs related to cyanobacteria and chloroplasts accounted for 3 to 25% of the communities. Oxygen profiles showed evidence for oxygenic photosynthesis at the surface of some mats, indicating the coexistence of photosynthetic and FeOB populations. The relative abundance of OTUs belonging to putative Fe-reducing bacteria (FeRB) averaged around 11% in the sampled <span class="hlt">iron</span> mats. Mats incubated anaerobically with 10 mM acetate rapidly initiated Fe reduction, indicating that active <span class="hlt">iron</span> cycling is likely. The prevalence of <span class="hlt">iron</span> mats on the tundra might impact the carbon cycle through lithoautotrophic chemosynthesis, anaerobic respiration of organic carbon coupled to <span class="hlt">iron</span> reduction, and the suppression of methanogenesis, and it potentially influences phosphorus dynamics through the adsorption of phosphorus to <span class="hlt">iron</span> <span class="hlt">oxides</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008BGD.....5.1825C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008BGD.....5.1825C"><span id="translatedtitle"><span class="hlt">Iron</span> <span class="hlt">oxide</span> deposits associated with the ectosymbiotic bacteria in the hydrothermal vent shrimp Rimicaris exoculata</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Corbari, L.; Cambon-Bonavita, M.-A.; Long, G. J.; Grandjean, F.; Zbinden, M.; Gaill, F.; Compère, P.</p> <p>2008-04-01</p> <p>The Rimicaris exoculata shrimp is considered a primary consumer that dominates the fauna of most Mid-Atlantic Ridge (MAR) hydrothermal ecosystems. These shrimps harbour in their gill chambers an important ectosymbiotic community of chemoautotrophic bacteria associated with <span class="hlt">iron</span> <span class="hlt">oxide</span> deposits. The structure and elemental composition of the minerals associated with these bacteria have been investigated by using X-ray microanalyses, light microscopy, and transmission, environmental scanning and scanning transmission electron microscopy. The nature of the <span class="hlt">iron</span> <span class="hlt">oxides</span> in shrimps obtained from the Rainbow vent field at 36°14.0' N, has also been determined by Mössbauer spectroscopy. This multidisciplinary approach has revealed that the three step-levels of mineral crust found in the Rimicaris exoculata shrimps consist of heavy concretions formed by nanoparticles of two-line ferrihydrite intermixed with minor inorganic SiO2, (Ca,Mg)SO4, and (Ca,Mg)3(PO4)2 minerals that may stabilise the ferrihydrite form of <span class="hlt">iron</span> <span class="hlt">oxides</span>. Morphological observations on the bacteria have revealed their close interactions with these minerals and, thus, indicate the biogenic origin of the <span class="hlt">iron</span> <span class="hlt">oxide</span> deposits. The evolution of the bacterial density in the three mineral crust levels is related to the amount of the <span class="hlt">iron</span> deposits and it is proposed that the lower crust level is the most likely region for the location of the <span class="hlt">iron-oxidizing</span> bacteria.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20665323','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20665323"><span id="translatedtitle">Adsorption of <span class="hlt">iron</span> cyanide complexes onto clay minerals, manganese <span class="hlt">oxide</span>, and soil.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kang, Dong-Hee; Schwab, A Paul; Johnston, C T; Banks, M Katherine</p> <p>2010-09-01</p> <p>The adsorption characteristics of an <span class="hlt">iron</span> cyanide complex, soluble Prussian blue KFe(III)[Fe(II)(CN)(6)], were evaluated for representative soil minerals and soil at pH 3.7, 6.4 and 9.7. Three specimen clay minerals (kaolinite, montmorillonite, and illite), two synthesized manganese <span class="hlt">oxides</span> (birnessite and cryptomelane), and a Drummer soil from Indiana were used as the adsorbents. Surface protonation of variable charge sites increased with decreasing pH yielding positively charged sites on crystal edges and enhancing the attractive force between minerals and <span class="hlt">iron</span> cyanide complexes. Anion adsorption on clays often is correlated to the metal content of the adsorbent, and a positive relationship was observed between <span class="hlt">iron</span> or aluminum content and Prussian blue adsorption. Illite had high extractable <span class="hlt">iron</span> and adsorbed more ferro-ferricyande anion, while kaolinite and montmorillonite had lower extractable <span class="hlt">iron</span> and adsorbed less. However, less pH effect was observed on the adsorption of <span class="hlt">iron</span> cyanide to manganese <span class="hlt">oxides</span>. This may due to the manganese <span class="hlt">oxide</span> mediated <span class="hlt">oxidation</span> of ferrocyanide [Fe(II)(CN)(6)(4-)], to ferricyanide [Fe(III)(CN)(6)(3-)], which has a low affinity for manganese <span class="hlt">oxides</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26369072','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26369072"><span id="translatedtitle">Nanobiocomposite from Collagen Waste Using <span class="hlt">Iron</span> <span class="hlt">Oxide</span> Nanoparticles and Its Conversion Into Magnetic Nanocarbon.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Thanikaivelan, P; Narayanan, T N; Gupta, B K; Reddy, A L M; Ajayan, P M</p> <p>2015-06-01</p> <p>Collagenous wastes discarded from leather industry were stabilized using superparamagnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles and further converted into a magnetic nanocarbon. Stabilization of collagen using <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles treatment (25% offer) was confirmed through differential scanning calorimetric analysis and further evidenced through scanning electron microscopic analysis. A simple high temperature treatment of the collagen-<span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticle composite at 850 degrees C for 2 h under Ar atmosphere yielded a bi-functional, magnetic and conducting, nanocarbon. The X-ray diffraction and Raman spectroscopic analysis reveal the partial graphitation and X-ray photoelectron spectroscopic results show the presence of trace-<span class="hlt">iron</span> containing carbon, naturally doped with nitrogen and oxygen. Transmission electron microscopic analysis show the presence of larger <span class="hlt">iron</span> <span class="hlt">oxide</span> nanocrystals embedded in graphitic carbon layers while superconducting quantum interference device based analysis reveals a perfect ferrimagnetic property with saturation magnetization. Thus, we have stabilized the collagen waste fibers using <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles and converted them into a bi-functional nanocarbon, which has potential for various applications including energy, leather making and environmental remediation. PMID:26369072</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5076882','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5076882"><span id="translatedtitle">The association between low-grade inflammation, <span class="hlt">iron</span> status and nucleic acid <span class="hlt">oxidation</span> in the elderly</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Broedbaek, Kasper; Siersma, Volkert; Andersen, Jon T.; Petersen, Morten; Afzal, Shoaib; Hjelvang, Brian; Weimann, Allan; Semba, Richard D.; Ferrucci, Luigi; Poulsen, Henrik E.</p> <p>2016-01-01</p> <p>This study applied a case-control approach to investigate the association between low-grade inflammation, defined by high values within the normal range of C-reactive protein (CRP) and interleukin-6 (IL-6), and urinary markers of nucleic acid <span class="hlt">oxidation</span>. No differences in excretion of urinary markers of nucleic acid <span class="hlt">oxidation</span> between cases and controls were found and multivariable linear regression analysis showed no association between urinary markers of nucleic acid <span class="hlt">oxidation</span> and inflammatory markers. Post-hoc multivariable linear regression analysis showed significant associations between nucleic acid <span class="hlt">oxidation</span> and various <span class="hlt">iron</span> status markers and especially a close relationship between nucleic acid <span class="hlt">oxidation</span> and ferritin. This study shows no association between low-grade inflammation and urinary markers of nucleic acid <span class="hlt">oxidation</span> in a population of elderly Italian people. The results suggest that low-grade inflammation only has a negligible impact on whole body nucleic acid <span class="hlt">oxidation</span>, whereas <span class="hlt">iron</span> status seems to be of great importance. PMID:21275071</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22215586','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22215586"><span id="translatedtitle">Effect of <span class="hlt">iron</span> <span class="hlt">oxide</span> loading on the phase transformation and physicochemical properties of nanosized mesoporous ZrO{sub 2}</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Basahel, S.N.; Ali, Tarek T.; Narasimharao, K.; Bagabas, A.A.; Mokhtar, M.</p> <p>2012-11-15</p> <p>Highlights: ► Modified preparation method for nanosized <span class="hlt">iron</span> <span class="hlt">oxide</span> supported ZrO{sub 2} catalysts. ► Systematic study of effect of high <span class="hlt">iron</span> <span class="hlt">oxide</span> loading over ZrO{sub 2}. ► Influence of <span class="hlt">iron</span> <span class="hlt">oxide</span> on the stabilization of tetragonal ZrO{sub 2} phase. ► A mesoporous nature of zirconia changed upon changing <span class="hlt">iron</span> <span class="hlt">oxide</span> loading. ► Surface to bulk migration of <span class="hlt">iron</span> <span class="hlt">oxide</span> evidenced by XPS technique. -- Abstract: Mesoporous ZrO{sub 2}-supported <span class="hlt">iron</span> <span class="hlt">oxide</span> materials were prepared with nominal loadings of <span class="hlt">iron</span> <span class="hlt">oxide</span> of 5, 10, 15 and 20 wt.% using a modified co-precipitation method. The physicochemical properties of the catalysts were characterized by thermogravimetric analysis, differential scanning calorimetry, X-ray diffraction, Raman spectroscopy, high resolution transmission electron microscopy, N{sub 2} adsorption, X-ray photoelectron spectroscopy and infrared spectroscopy methods. A delay in the ZrO{sub 2} phase transformation as a result of the incorporation of <span class="hlt">iron</span> was determined using TG/DSC measurements. XRD, Raman spectroscopy and HRTEM results revealed that an increase of <span class="hlt">iron</span> <span class="hlt">oxide</span> loading from 5 to 15 wt.% enhanced the transformation of the monoclinic to tetragonal phase. Unexpectedly, 20 wt.% <span class="hlt">iron</span> <span class="hlt">oxide</span> loading was required for complete tetragonal structure stabilization due to the mesoporosity of the ZrO{sub 2} support. <span class="hlt">Iron</span> <span class="hlt">oxide</span> loadings from 5 to 15 wt.% showed an increase in the BET-surface area due to the presence of amorphous <span class="hlt">iron</span> <span class="hlt">oxide</span> on the surface. XPS and FTIR results indicated that increasing the <span class="hlt">iron</span> <span class="hlt">oxide</span> content to 20 wt.% resulted in stabilization of the tetragonal zirconia phase as a result of surface-to-bulk migration and incorporation of Fe{sup 3+} ions in the ZrO{sub 2} lattice.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23895380','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23895380"><span id="translatedtitle">Water <span class="hlt">oxidation</span> catalysis with nonheme <span class="hlt">iron</span> complexes under acidic and basic conditions: homogeneous or heterogeneous?</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hong, Dachao; Mandal, Sukanta; Yamada, Yusuke; Lee, Yong-Min; Nam, Wonwoo; Llobet, Antoni; Fukuzumi, Shunichi</p> <p>2013-08-19</p> <p>Thermal water <span class="hlt">oxidation</span> by cerium(IV) ammonium nitrate (CAN) was catalyzed by nonheme <span class="hlt">iron</span> complexes, such as Fe(BQEN)(OTf)2 (1) and Fe(BQCN)(OTf)2 (2) (BQEN = N,N'-dimethyl-N,N'-bis(8-quinolyl)ethane-1,2-diamine, BQCN = N,N'-dimethyl-N,N'-bis(8-quinolyl)cyclohexanediamine, OTf = CF3SO3(-)) in a nonbuffered aqueous solution; turnover numbers of 80 ± 10 and 20 ± 5 were obtained in the O2 evolution reaction by 1 and 2, respectively. The ligand dissociation of the <span class="hlt">iron</span> complexes was observed under acidic conditions, and the dissociated ligands were <span class="hlt">oxidized</span> by CAN to yield CO2. We also observed that 1 was converted to an <span class="hlt">iron</span>(IV)-oxo complex during the water <span class="hlt">oxidation</span> in competition with the ligand <span class="hlt">oxidation</span>. In addition, oxygen exchange between the <span class="hlt">iron</span>(IV)-oxo complex and H2(18)O was found to occur at a much faster rate than the oxygen evolution. These results indicate that the <span class="hlt">iron</span> complexes act as the true homogeneous catalyst for water <span class="hlt">oxidation</span> by CAN at low pHs. In contrast, light-driven water <span class="hlt">oxidation</span> using [Ru(bpy)3](2+) (bpy = 2,2'-bipyridine) as a photosensitizer and S2O8(2-) as a sacrificial electron acceptor was catalyzed by <span class="hlt">iron</span> hydroxide nanoparticles derived from the <span class="hlt">iron</span> complexes under basic conditions as the result of the ligand dissociation. In a buffer solution (initial pH 9.0) formation of the <span class="hlt">iron</span> hydroxide nanoparticles with a size of around 100 nm at the end of the reaction was monitored by dynamic light scattering (DLS) in situ and characterized by X-ray photoelectron spectra (XPS) and transmission electron microscope (TEM) measurements. We thus conclude that the water <span class="hlt">oxidation</span> by CAN was catalyzed by short-lived homogeneous <span class="hlt">iron</span> complexes under acidic conditions, whereas <span class="hlt">iron</span> hydroxide nanoparticles derived from <span class="hlt">iron</span> complexes act as a heterogeneous catalyst in the light-driven water <span class="hlt">oxidation</span> reaction under basic conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/12450111','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/12450111"><span id="translatedtitle">Ferrous-<span class="hlt">iron</span>-dependent uptake of L-glutamate by a mesophilic, mixotrophic <span class="hlt">iron-oxidizing</span> bacterium strain OKM-9.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Inoue, Takao; Kamimura, Kazuo; Sugio, Tsuyoshi</p> <p>2002-10-01</p> <p>Strain OKM-9 is a mesophilic, mixotrophic <span class="hlt">iron-oxidizing</span> bacterium that absolutely requires ferrous <span class="hlt">iron</span> as its energy source and L-amino acids (including L-glutamate) as carbon sources for growth. The properties of the L-glutamate transport system were studied with OKM-9 resting cells, plasma membranes, and actively reconstituted proteoliposomes. L-Glutamate uptake into resting cells was totally dependent on ferrous <span class="hlt">iron</span> that was added to the reaction mixture. Potassium cyanide, an <span class="hlt">iron</span> oxidase inhibitor, completely inhibited the activity at 1 mM. The optimum pH for Fe2+-dependent uptake activity of L-glutamate was 3.5-4.0. Uptake activity was dependent on the concentration of the L-glutamate. The Km and Vmax for L-glutamate were 0.4 mM and 11.3 nmol x min(-1) x mg(-1), respectively. L-Aspartate, D-aspartate, D-glutamate, and L-cysteine strongly inhibited L-glutamate uptake. L-Aspartate competitively inhibited the activity, and the apparent Ki for this amino acid was 75.9 microM. 2,4-Dinitrophenol, carbonyl cyanide m-chlorophenylhydrazone, gramicidin D, valinomycin, and monensin did not inhibit Fe2+-dependent L-glutamate uptake. The OKM-9 plasma membranes had approximately 40% of the <span class="hlt">iron-oxidizing</span> activity of the resting cells and approximately 85% of the Fe2+-dependent uptake activity. The glutamate transport system was solubilized from the membranes with 1% n-octyl-beta-D-glucopyranoside and reconstituted into a lecithin liposome. The L-glutamate transport activity of the reconstituted proteoliposomes was 8-fold than that of the resting cells. The Fe2+-dependent L-glutamate uptake observed here seems to explain the mixotrophic nature of this strain, which absolutely requires Fe2+ <span class="hlt">oxidation</span> when using amino acids as carbon sources. PMID:12450111</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5015080','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5015080"><span id="translatedtitle">Discovery of Fe7O9: a new <span class="hlt">iron</span> <span class="hlt">oxide</span> with a complex monoclinic structure</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Sinmyo, Ryosuke; Bykova, Elena; Ovsyannikov, Sergey V.; McCammon, Catherine; Kupenko, Ilya; Ismailova, Leyla; Dubrovinsky, Leonid</p> <p>2016-01-01</p> <p><span class="hlt">Iron</span> <span class="hlt">oxides</span> are fundamentally important compounds for basic and applied sciences as well as in numerous industrial applications. In this work we report the synthesis and investigation of a new binary <span class="hlt">iron</span> <span class="hlt">oxide</span> with the hitherto unknown stoichiometry of Fe7O9. This new <span class="hlt">oxide</span> was synthesized at high-pressure high-temperature (HP-HT) conditions, and its black single crystals were successfully recovered at ambient conditions. By means of single crystal X-ray diffraction we determined that Fe7O9 adopts a monoclinic C2/m lattice with the most distorted crystal structure among the binary <span class="hlt">iron</span> <span class="hlt">oxides</span> known to date. The synthesis of Fe7O9 opens a new portal to exotic <span class="hlt">iron</span>-rich (M,Fe)7O9 <span class="hlt">oxides</span> with unusual stoichiometry and distorted crystal structures. Moreover, the crystal structure and phase relations of such new <span class="hlt">iron</span> <span class="hlt">oxide</span> groups may provide new insight into the cycling of volatiles in the Earth’s interior. PMID:27605075</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27605075','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27605075"><span id="translatedtitle">Discovery of Fe7O9: a new <span class="hlt">iron</span> <span class="hlt">oxide</span> with a complex monoclinic structure.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sinmyo, Ryosuke; Bykova, Elena; Ovsyannikov, Sergey V; McCammon, Catherine; Kupenko, Ilya; Ismailova, Leyla; Dubrovinsky, Leonid</p> <p>2016-01-01</p> <p><span class="hlt">Iron</span> <span class="hlt">oxides</span> are fundamentally important compounds for basic and applied sciences as well as in numerous industrial applications. In this work we report the synthesis and investigation of a new binary <span class="hlt">iron</span> <span class="hlt">oxide</span> with the hitherto unknown stoichiometry of Fe7O9. This new <span class="hlt">oxide</span> was synthesized at high-pressure high-temperature (HP-HT) conditions, and its black single crystals were successfully recovered at ambient conditions. By means of single crystal X-ray diffraction we determined that Fe7O9 adopts a monoclinic C2/m lattice with the most distorted crystal structure among the binary <span class="hlt">iron</span> <span class="hlt">oxides</span> known to date. The synthesis of Fe7O9 opens a new portal to exotic <span class="hlt">iron</span>-rich (M,Fe)7O9 <span class="hlt">oxides</span> with unusual stoichiometry and distorted crystal structures. Moreover, the crystal structure and phase relations of such new <span class="hlt">iron</span> <span class="hlt">oxide</span> groups may provide new insight into the cycling of volatiles in the Earth's interior. PMID:27605075</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27153075','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27153075"><span id="translatedtitle"><span class="hlt">Oxidative</span> Profile and δ-Aminolevulinate Dehydratase Activity in Healthy Pregnant Women with <span class="hlt">Iron</span> Supplementation.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>De Lucca, Leidiane; Rodrigues, Fabiane; Jantsch, Letícia B; Neme, Walter S; Gallarreta, Francisco M P; Gonçalves, Thissiane L</p> <p>2016-05-03</p> <p>An <span class="hlt">oxidative</span> burst occurs during pregnancy due to the large consumption of oxygen in the tissues and an increase in metabolic demands in response to maternal physiological changes and fetal growth. This study aimed to determine the <span class="hlt">oxidative</span> profile and activity of δ-aminolevulinate dehydratase (δ-ALA-D) in pregnant women who received <span class="hlt">iron</span> supplementation. <span class="hlt">Oxidative</span> stress parameters were evaluated in 25 pregnant women with <span class="hlt">iron</span> supplementation, 25 pregnant women without supplementation and 25 non-pregnant women. The following <span class="hlt">oxidative</span> stress parameters were evaluated: thiobarbituric acid reactive substances (TBARS), protein thiol groups (P-SH), non-protein thiol levels (NP-SH), vitamin C levels, catalase and δ-ALA-D activity. Markers of <span class="hlt">oxidative</span> stress and cell damage, such as TBARS in plasma were significantly higher in pregnant women without supplementation. Levels of P-SH, NP-SH and δ-ALA-D activity were significantly lower in pregnant women without supplementation compared to non-pregnant and pregnant women with supplementation, while vitamin C levels were significantly lower in pregnant women without supplementation when compared to non-pregnant women. The increase in the generation of <span class="hlt">oxidative</span> species and decrease of antioxidants suggest the loss of physiological <span class="hlt">oxidative</span> balance during normal pregnancy, which was not observed in pregnant women with <span class="hlt">iron</span> supplementation, suggesting a protective effect of <span class="hlt">iron</span> against <span class="hlt">oxidative</span> damage.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_22 --> <div id="page_23" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="441"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4881088','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4881088"><span id="translatedtitle"><span class="hlt">Oxidative</span> Profile and δ-Aminolevulinate Dehydratase Activity in Healthy Pregnant Women with <span class="hlt">Iron</span> Supplementation</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>De Lucca, Leidiane; Rodrigues, Fabiane; Jantsch, Letícia B.; Neme, Walter S.; Gallarreta, Francisco M. P.; Gonçalves, Thissiane L.</p> <p>2016-01-01</p> <p>An <span class="hlt">oxidative</span> burst occurs during pregnancy due to the large consumption of oxygen in the tissues and an increase in metabolic demands in response to maternal physiological changes and fetal growth. This study aimed to determine the <span class="hlt">oxidative</span> profile and activity of δ-aminolevulinate dehydratase (δ-ALA-D) in pregnant women who received <span class="hlt">iron</span> supplementation. <span class="hlt">Oxidative</span> stress parameters were evaluated in 25 pregnant women with <span class="hlt">iron</span> supplementation, 25 pregnant women without supplementation and 25 non-pregnant women. The following <span class="hlt">oxidative</span> stress parameters were evaluated: thiobarbituric acid reactive substances (TBARS), protein thiol groups (P-SH), non-protein thiol levels (NP-SH), vitamin C levels, catalase and δ-ALA-D activity. Markers of <span class="hlt">oxidative</span> stress and cell damage, such as TBARS in plasma were significantly higher in pregnant women without supplementation. Levels of P-SH, NP-SH and δ-ALA-D activity were significantly lower in pregnant women without supplementation compared to non-pregnant and pregnant women with supplementation, while vitamin C levels were significantly lower in pregnant women without supplementation when compared to non-pregnant women. The increase in the generation of <span class="hlt">oxidative</span> species and decrease of antioxidants suggest the loss of physiological <span class="hlt">oxidative</span> balance during normal pregnancy, which was not observed in pregnant women with <span class="hlt">iron</span> supplementation, suggesting a protective effect of <span class="hlt">iron</span> against <span class="hlt">oxidative</span> damage. PMID:27153075</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25000534','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25000534"><span id="translatedtitle"><span class="hlt">Iron-oxide</span>-supported nanocarbon in lithium-ion batteries, medical, catalytic, and environmental applications.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Tuček, Jiří; Kemp, Kingsley Christian; Kim, Kwang Soo; Zbořil, Radek</p> <p>2014-08-26</p> <p>Owing to the three different orbital hybridizations carbon can adopt, the existence of various carbon nanoallotropes differing also in dimensionality has been already affirmed with other structures predicted and expected to emerge in the future. Despite numerous unique features and applications of 2D graphene, 1D carbon nanotubes, or 0D fullerenes, nanodiamonds, and carbon quantum dots, which have been already heavily explored, any of the existing carbon allotropes do not offer competitive magnetic properties. For challenging applications, carbon nanoallotropes are functionalized with magnetic species, especially of <span class="hlt">iron</span> <span class="hlt">oxide</span> nature, due to their interesting magnetic properties (superparamagnetism and strong magnetic response under external magnetic fields), easy availability, biocompatibility, and low cost. In addition, combination of <span class="hlt">iron</span> <span class="hlt">oxides</span> (magnetite, maghemite, hematite) and carbon nanostructures brings enhanced electrochemical performance and (photo)catalytic capability due to synergetic and cooperative effects. This work aims at reviewing these advanced applications of <span class="hlt">iron-oxide</span>-supported nanocarbon composites where <span class="hlt">iron</span> <span class="hlt">oxides</span> play a diverse role. Various architectures of carbon/<span class="hlt">iron</span> <span class="hlt">oxide</span> nanocomposites, their synthetic procedures, physicochemical properties, and applications are discussed in details. A special attention is devoted to hybrids of carbon nanotubes and rare forms (mesoporous carbon, nanofoam) with magnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> carriers for advanced environmental technologies. The review also covers the huge application potential of graphene/<span class="hlt">iron</span> <span class="hlt">oxide</span> nanocomposites in the field of energy storage, biomedicine, and remediation of environment. Among various discussed medical applications, magnetic composites of zero-dimensional fullerenes and carbon dots are emphasized as promising candidates for complex theranostics and dual magneto-fluorescence imaging.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23747468','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23747468"><span id="translatedtitle">Selective catalytic <span class="hlt">oxidation</span> of H₂S over <span class="hlt">iron</span> <span class="hlt">oxide</span> supported on alumina-intercalated Laponite clay catalysts.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhang, Xin; Dou, Guangyu; Wang, Zhuo; Li, Li; Wang, Yufei; Wang, Hailin; Hao, Zhengping</p> <p>2013-09-15</p> <p>A series of <span class="hlt">iron</span> <span class="hlt">oxide</span> supported on alumina-intercalated clay catalysts (named Fe/Al-Lap catalysts) with mesoporous structure and high specific surface area were prepared. The structural and chemical properties were studied by nitrogen sorption isotherms, X-ray diffraction (XRD), UV-vis diffuse reflectance spectra (UV-vis DRS), X-ray photoelectron spectra (XPS), Fourier transform infrared spectroscopy (FTIR), H₂ temperature-programmed reduction (H₂-TPR) and NH₃ temperature-programmed desorption (NH3-TPD) techniques. It was realized that <span class="hlt">iron</span> <span class="hlt">oxide</span> mainly existed in the form of isolated Fe(3+) in an <span class="hlt">oxidic</span> environment. Fe/Al-Lap catalysts showed high catalytic activities in the temperature range of 120-200 °C without the presence of excessive O₂. This can be attributed to the interaction between <span class="hlt">iron</span> <span class="hlt">oxide</span> and alumina, which improve the redox property of Fe(3+) efficiently. In addition, the strong acidity of catalysts and good dispersion of <span class="hlt">iron</span> <span class="hlt">oxide</span> were also beneficial to <span class="hlt">oxidation</span> reaction. Among them, 7% Fe/Al-Lap catalyst presented the best catalytic performance at 180 °C. Finally, the catalytic and deactivation mechanisms were explored.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25704059','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25704059"><span id="translatedtitle">DLVO and XDLVO calculations for bacteriophage MS2 adhesion to <span class="hlt">iron</span> <span class="hlt">oxide</span> particles.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Park, Jeong-Ann; Kim, Song-Bae</p> <p>2015-10-01</p> <p>In this study, batch experiments were performed to examine the adhesion of bacteriophage MS2 to three <span class="hlt">iron</span> <span class="hlt">oxide</span> particles (IOP1, IOP2 and IOP3) with different particle properties. The characteristics of MS2 and <span class="hlt">iron</span> <span class="hlt">oxides</span> were analyzed using various techniques to construct the classical DLVO and XDLVO potential energy profiles between MS2 and <span class="hlt">iron</span> <span class="hlt">oxides</span>. X-ray diffractometry peaks indicated that IOP1 was mainly composed of maghemite (γ-Fe2O3), but also contained some goethite (α-FeOOH). IOP2 was composed of hematite (α-Fe2O3) and IOP3 was composed of <span class="hlt">iron</span> (Fe), magnetite (Fe3O4) and <span class="hlt">iron</span> <span class="hlt">oxide</span> (FeO). Transmission electron microscope images showed that the primary particle size of IOP1 (γ-Fe2O3) was 12.3±4.1nm. IOP2 and IOP3 had primary particle sizes of 167±35nm and 484±192nm, respectively. A surface angle analyzer demonstrated that water contact angles of IOP1, IOP2, IOP3 and MS2 were 44.83, 64.00, 34.33 and 33.00°, respectively. A vibrating sample magnetometer showed that the magnetic saturations of IOP1, IOP2 and IOP3 were 176.87, 17.02 and 946.85kA/m, respectively. Surface potentials measured in artificial ground water (AGW; 0.075mM CaCl2, 0.082mM MgCl2, 0.051mM KCl, and 1.5mM NaHCO3; pH7.6) indicated that <span class="hlt">iron</span> <span class="hlt">oxides</span> and MS2 were negatively charged in AGW (IOP1=-0.0185V; IOP2=-0.0194V; IOP3=-0.0301V; MS2=-0.0245V). Batch experiments demonstrated that MS2 adhesion to <span class="hlt">iron</span> <span class="hlt">oxides</span> was favorable in the order of IOP1>IOP2>IOP3. This tendency was well predicted by the classical DLVO model. In the DLVO calculations, both the sphere-plate and sphere-sphere geometries predicted the same trend of MS2 adhesion to <span class="hlt">iron</span> <span class="hlt">oxides</span>. Additionally, noticeable differences were not found between the DLVO and XDLVO interaction energy profiles, indicating that hydrophobic interactions did not play a major role; electrostatic interactions, however, did influence MS2 adhesion to <span class="hlt">iron</span> <span class="hlt">oxides</span>. Furthermore, the aggregation of <span class="hlt">iron</span> <span class="hlt">oxides</span> was investigated with a modified XDLVO</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25704059','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25704059"><span id="translatedtitle">DLVO and XDLVO calculations for bacteriophage MS2 adhesion to <span class="hlt">iron</span> <span class="hlt">oxide</span> particles.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Park, Jeong-Ann; Kim, Song-Bae</p> <p>2015-10-01</p> <p>In this study, batch experiments were performed to examine the adhesion of bacteriophage MS2 to three <span class="hlt">iron</span> <span class="hlt">oxide</span> particles (IOP1, IOP2 and IOP3) with different particle properties. The characteristics of MS2 and <span class="hlt">iron</span> <span class="hlt">oxides</span> were analyzed using various techniques to construct the classical DLVO and XDLVO potential energy profiles between MS2 and <span class="hlt">iron</span> <span class="hlt">oxides</span>. X-ray diffractometry peaks indicated that IOP1 was mainly composed of maghemite (γ-Fe2O3), but also contained some goethite (α-FeOOH). IOP2 was composed of hematite (α-Fe2O3) and IOP3 was composed of <span class="hlt">iron</span> (Fe), magnetite (Fe3O4) and <span class="hlt">iron</span> <span class="hlt">oxide</span> (FeO). Transmission electron microscope images showed that the primary particle size of IOP1 (γ-Fe2O3) was 12.3±4.1nm. IOP2 and IOP3 had primary particle sizes of 167±35nm and 484±192nm, respectively. A surface angle analyzer demonstrated that water contact angles of IOP1, IOP2, IOP3 and MS2 were 44.83, 64.00, 34.33 and 33.00°, respectively. A vibrating sample magnetometer showed that the magnetic saturations of IOP1, IOP2 and IOP3 were 176.87, 17.02 and 946.85kA/m, respectively. Surface potentials measured in artificial ground water (AGW; 0.075mM CaCl2, 0.082mM MgCl2, 0.051mM KCl, and 1.5mM NaHCO3; pH7.6) indicated that <span class="hlt">iron</span> <span class="hlt">oxides</span> and MS2 were negatively charged in AGW (IOP1=-0.0185V; IOP2=-0.0194V; IOP3=-0.0301V; MS2=-0.0245V). Batch experiments demonstrated that MS2 adhesion to <span class="hlt">iron</span> <span class="hlt">oxides</span> was favorable in the order of IOP1>IOP2>IOP3. This tendency was well predicted by the classical DLVO model. In the DLVO calculations, both the sphere-plate and sphere-sphere geometries predicted the same trend of MS2 adhesion to <span class="hlt">iron</span> <span class="hlt">oxides</span>. Additionally, noticeable differences were not found between the DLVO and XDLVO interaction energy profiles, indicating that hydrophobic interactions did not play a major role; electrostatic interactions, however, did influence MS2 adhesion to <span class="hlt">iron</span> <span class="hlt">oxides</span>. Furthermore, the aggregation of <span class="hlt">iron</span> <span class="hlt">oxides</span> was investigated with a modified XDLVO</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.B13C0635B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.B13C0635B"><span id="translatedtitle">In-Situ Incubation of <span class="hlt">Iron</span>-Sulfide Mineral in Seawater Reveals Colonization by <span class="hlt">Iron-Oxidizing</span> Gammaproteobacteria and Zetaproteobacteria.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Barco, R. A.; Ramírez, G. A.; Sylvan, J. B.; Edwards, K. J.</p> <p>2015-12-01</p> <p>Sulfide mineral precipitation occurs at mid-ocean ridge (MOR) spreading centers, both in the form of plume particles and massive sulfide structures. A common constituent of MOR sulfide mineral is pyrrhotite (Fe1-xS). This mineral was chosen as a substrate for in-situ incubation studies in the shallow waters of Catalina Islands, CA to investigate the colonization of <span class="hlt">iron-oxidizing</span> bacteria. Gammaproteobacteria and Alphaproteobacteria largely dominated the bacterial community on pyrrhotite samples incubated in the water column. Pyrrhotite samples incubated at the sediment/water column interface showed more even dominance by Gammaproteobacteria, Alphaproteobacteria, Deltaproteobacteria and Bacteroidetes. Cultivations that originated from these pyrrhotite samples resulted in the enrichment of Zetaproteobacteria with either twisted-stalks (Mariprofundus) or sheath structures. Additionally, a candidate novel Gammaproteobacterium was isolated and shown to grow autotrophically via the <span class="hlt">oxidation</span> of <span class="hlt">iron</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19940007656&hterms=chemical+weathering&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dchemical%2Bweathering','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19940007656&hterms=chemical+weathering&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dchemical%2Bweathering"><span id="translatedtitle">Chemical weathering on Mars: Rate of <span class="hlt">oxidation</span> of <span class="hlt">iron</span> dissolved in brines</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Burns, Roger G.</p> <p>1993-01-01</p> <p>Salts believed to occur in Martian regolith imply that brines occur on Mars, which may have facilitated the <span class="hlt">oxidation</span> of dissolved Fe(2+) ions after they were released during chemical weathering of basaltic ferromagnesian silicate and <span class="hlt">iron</span> sulfide minerals. Calculations show that the rate of <span class="hlt">oxidation</span> of Fe(2+) ions at -35 C in a 6M chloride-sulfate brine that might exist on Mars is about 10(exp 6) times slower that the <span class="hlt">oxidation</span> rate of <span class="hlt">iron</span> in ice-cold terrestrial seawater.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/16805609','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/16805609"><span id="translatedtitle">Gold and gold-<span class="hlt">iron</span> <span class="hlt">oxide</span> magnetic glyconanoparticles: synthesis, characterization and magnetic properties.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>de la Fuente, Jesús M; Alcántara, David; Eaton, Peter; Crespo, Patricia; Rojas, Teresa C; Fernandez, Asunción; Hernando, Antonio; Penadés, Soledad</p> <p>2006-07-01</p> <p>The preparation, characterization and the magnetic properties of gold and gold-<span class="hlt">iron</span> <span class="hlt">oxide</span> glyconanoparticles (GNPs) are described. Glyconanoparticles were prepared in a single step procedure in the presence of aqueous solution of thiol functionalized neoglycoconjugates and either gold salts or both gold and <span class="hlt">iron</span> salts. Neoglycoconjugates of lactose and maltose disaccharides with different linkers were used. <span class="hlt">Iron</span>-free gold or gold-<span class="hlt">iron</span> <span class="hlt">oxide</span> GNPs with controlled gold-<span class="hlt">iron</span> ratios were obtained. The average core-size diameters are in the range of 1.5-2.5 nm. The GNPs are fully characterized by (1)H NMR spectrometry, transmission electron microscopy (TEM), and UV-vis and X-ray absorption (XAS) spectroscopies. Inductive plasma-atomic emission spectrometry (ICP) and elemental analysis gave the average number of neoglycoconjugates per cluster. The magnetic properties were measured in a SQUID magnetometer. The most remarkable results was the observation of a permanent magnetism up to room temperature in the <span class="hlt">iron</span>-free gold GNPs, that was not present in the corresponding gold-<span class="hlt">iron</span> <span class="hlt">oxide</span> GNPs. PMID:16805609</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/16805609','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/16805609"><span id="translatedtitle">Gold and gold-<span class="hlt">iron</span> <span class="hlt">oxide</span> magnetic glyconanoparticles: synthesis, characterization and magnetic properties.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>de la Fuente, Jesús M; Alcántara, David; Eaton, Peter; Crespo, Patricia; Rojas, Teresa C; Fernandez, Asunción; Hernando, Antonio; Penadés, Soledad</p> <p>2006-07-01</p> <p>The preparation, characterization and the magnetic properties of gold and gold-<span class="hlt">iron</span> <span class="hlt">oxide</span> glyconanoparticles (GNPs) are described. Glyconanoparticles were prepared in a single step procedure in the presence of aqueous solution of thiol functionalized neoglycoconjugates and either gold salts or both gold and <span class="hlt">iron</span> salts. Neoglycoconjugates of lactose and maltose disaccharides with different linkers were used. <span class="hlt">Iron</span>-free gold or gold-<span class="hlt">iron</span> <span class="hlt">oxide</span> GNPs with controlled gold-<span class="hlt">iron</span> ratios were obtained. The average core-size diameters are in the range of 1.5-2.5 nm. The GNPs are fully characterized by (1)H NMR spectrometry, transmission electron microscopy (TEM), and UV-vis and X-ray absorption (XAS) spectroscopies. Inductive plasma-atomic emission spectrometry (ICP) and elemental analysis gave the average number of neoglycoconjugates per cluster. The magnetic properties were measured in a SQUID magnetometer. The most remarkable results was the observation of a permanent magnetism up to room temperature in the <span class="hlt">iron</span>-free gold GNPs, that was not present in the corresponding gold-<span class="hlt">iron</span> <span class="hlt">oxide</span> GNPs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ApSS..344....9H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ApSS..344....9H"><span id="translatedtitle">Degradation of organophosphorus pesticide parathion methyl on nanostructured titania-<span class="hlt">iron</span> mixed <span class="hlt">oxides</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Henych, Jiří; Štengl, Václav; Slušná, Michaela; Matys Grygar, Tomáš; Janoš, Pavel; Kuráň, Pavel; Štastný, Martin</p> <p>2015-07-01</p> <p>Titania-<span class="hlt">iron</span> mixed <span class="hlt">oxides</span> with various Ti:Fe ratio were prepared by homogeneous hydrolysis of aqueous solutions of titanium(IV) oxysulphate and <span class="hlt">iron</span>(III) sulphate with urea as a precipitating agent. The synthesized samples were characterized by X-ray diffraction, Raman and infrared spectroscopy, scanning and transmission electron microscopy, XRF analysis, specific surface area (BET) and porosity determination (BJH). These <span class="hlt">oxides</span> were used for degradation of organophosporus pesticide parathion methyl. The highest degradation efficiency approaching <70% was found for the samples with Ti:Fe ratio 0.25:1 and 1:0.25. Contrary, parathion methyl was not degraded on the surfaces of pure <span class="hlt">oxides</span>. In general, the highest degradation rate exhibited samples consisted of the <span class="hlt">iron</span> or titanium <span class="hlt">oxide</span> containing a moderate amount of the admixture. However, distinct correlations between the degradation rate and the sorbent composition were not identified.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4559654','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4559654"><span id="translatedtitle"><span class="hlt">Iron</span> is a signal for Stenotrophomonas maltophilia biofilm formation, <span class="hlt">oxidative</span> stress response, OMPs expression, and virulence</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>García, Carlos A.; Alcaraz, Eliana S.; Franco, Mirta A.; Passerini de Rossi, Beatriz N.</p> <p>2015-01-01</p> <p>Stenotrophomonas maltophilia is an emerging nosocomial pathogen. In many bacteria <span class="hlt">iron</span> availability regulates, through the Fur system, not only <span class="hlt">iron</span> homeostasis but also virulence. The aim of this work was to assess the role of <span class="hlt">iron</span> on S. maltophilia biofilm formation, EPS production, <span class="hlt">oxidative</span> stress response, OMPs regulation, quorum sensing (QS), and virulence. Studies were done on K279a and its isogenic fur mutant F60 cultured in the presence or absence of dipyridyl. This is the first report of spontaneous fur mutants obtained in S. maltophilia. F60 produced higher amounts of biofilms than K279a and CLSM analysis demonstrated improved adherence and biofilm organization. Under <span class="hlt">iron</span> restricted conditions, K279a produced biofilms with more biomass and enhanced thickness. In addition, F60 produced higher amounts of EPS than K279a but with a similar composition, as revealed by ATR-FTIR spectroscopy. With respect to the <span class="hlt">oxidative</span> stress response, MnSOD was the only SOD isoenzyme detected in K279a. F60 presented higher SOD activity than the wt strain in planktonic and biofilm cultures, and <span class="hlt">iron</span> deprivation increased K279a SOD activity. Under <span class="hlt">iron</span> starvation, SDS-PAGE profile from K279a presented two <span class="hlt">iron</span>-repressed proteins. Mass spectrometry analysis revealed homology with FepA and another putative TonB-dependent siderophore receptor of K279a. In silico analysis allowed the detection of potential Fur boxes in the respective coding genes. K279a encodes the QS diffusible signal factor (DSF). Under <span class="hlt">iron</span> restriction K279a produced higher amounts of DSF than under <span class="hlt">iron</span> rich condition. Finally, F60 was more virulent than K279a in the Galleria mellonella killing assay. These results put in evidence that <span class="hlt">iron</span> levels regulate, likely through the Fur system, S. maltophilia biofilm formation, <span class="hlt">oxidative</span> stress response, OMPs expression, DSF production and virulence. PMID:26388863</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27440425','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27440425"><span id="translatedtitle">Pollution Control Meets Sustainability: Structure-Activity Studies on New <span class="hlt">Iron</span> <span class="hlt">Oxide</span>-Based CO <span class="hlt">Oxidation</span> Catalysts.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Schoch, Roland; Bauer, Matthias</p> <p>2016-08-01</p> <p>A new class of catalysts for the <span class="hlt">oxidation</span> of CO based on <span class="hlt">iron</span> <span class="hlt">oxide</span> as a biocompatible, earth-abundant and non-toxic metal is presented. The catalytic activities achieved with these catalysts provide promising milestones towards the substitution of noble metals in CO <span class="hlt">oxidation</span> catalysts. The catalysts can be obtained by using <span class="hlt">iron</span> core-shell nanoparticle precursors. The metal used for the shell material determines whether the <span class="hlt">iron</span> core is integrated in or isolated from the support. The active <span class="hlt">iron</span> site is effectively integrated into the γ-Al2 O3 support if an aluminum shell is present in the core-shell precursor. When the metal used for the shell is different from the support, an isolated structure is formed. Using this directed synthesis approach, different <span class="hlt">iron</span> <span class="hlt">oxide</span> species can be obtained and their structural differences are linked to distinct catalytic activities, as demonstrated by combined in-depth analytical studies using XRD, X-ray absorption spectroscopy (XAS), UV/Vis, and Brunauer-Emmett-Teller (BET) analysis. The key species responsible for high catalytic activity is identified as isolated tetrahedrally coordinated Fe(III) centers, whereas aggregation leads to a reduction in activity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22210211','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22210211"><span id="translatedtitle">Superparamagnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles as radiosensitizer via enhanced reactive oxygen species formation</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Klein, Stefanie; Sommer, Anja; Distel, Luitpold V.R.; Neuhuber, Winfried; Kryschi, Carola</p> <p>2012-08-24</p> <p>Highlights: Black-Right-Pointing-Pointer Ultrasmall citrate-coated SPIONs with {gamma}Fe{sub 2}O{sub 3} and Fe{sub 3}O{sub 4} structure were prepared. Black-Right-Pointing-Pointer SPIONs uptaken by MCF-7 cells increase the ROS production for about 240%. Black-Right-Pointing-Pointer The SPION induced ROS production is due to released <span class="hlt">iron</span> ions and catalytically active surfaces. Black-Right-Pointing-Pointer Released <span class="hlt">iron</span> ions and SPION surfaces initiate the Fenton and Haber-Weiss reaction. Black-Right-Pointing-Pointer X-ray irradiation of internalized SPIONs leads to an increase of catalytically active surfaces. -- Abstract: Internalization of citrate-coated and uncoated superparamagnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles by human breast cancer (MCF-7) cells was verified by transmission electron microscopy imaging. Cytotoxicity studies employing metabolic and trypan blue assays manifested their excellent biocompatibility. The production of reactive oxygen species in <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticle loaded MCF-7 cells was explained to originate from both, the release of <span class="hlt">iron</span> ions and their catalytically active surfaces. Both initiate the Fenton and Haber-Weiss reaction. Additional <span class="hlt">oxidative</span> stress caused by X-ray irradiation of MCF-7 cells was attributed to the increase of catalytically active <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticle surfaces.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24992833','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24992833"><span id="translatedtitle">Comparison of various <span class="hlt">iron</span> chelators and prochelators as protective agents against cardiomyocyte <span class="hlt">oxidative</span> injury.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Jansová, Hana; Macháček, Miloslav; Wang, Qin; Hašková, Pavlína; Jirkovská, Anna; Potůčková, Eliška; Kielar, Filip; Franz, Katherine J; Simůnek, Tomáš</p> <p>2014-09-01</p> <p><span class="hlt">Oxidative</span> stress is a common denominator of numerous cardiovascular disorders. Free cellular <span class="hlt">iron</span> catalyzes the formation of highly toxic hydroxyl radicals, and <span class="hlt">iron</span> chelation may thus be an effective therapeutic approach. However, using classical <span class="hlt">iron</span> chelators in diseases without <span class="hlt">iron</span> overload poses risks that necessitate more advanced approaches, such as prochelators that are activated to chelate <span class="hlt">iron</span> only under disease-specific <span class="hlt">oxidative</span> stress conditions. In this study, three cell-membrane-permeable <span class="hlt">iron</span> chelators (clinically used deferasirox and experimental SIH and HAPI) and five boronate-masked prochelator analogs were evaluated for their ability to protect cardiac cells against <span class="hlt">oxidative</span> injury induced by hydrogen peroxide. Whereas the deferasirox-derived agents TIP and TRA-IMM displayed negligible protection and even considerable toxicity, the aroylhydrazone prochelators BHAPI and BSIH-PD provided significant cytoprotection and displayed lower toxicity after prolonged cellular exposure compared to their parent chelators HAPI and SIH, respectively. Overall, the most favorable properties in terms of protective efficiency and low inherent cytotoxicity were observed with the aroylhydrazone prochelator BSIH. BSIH efficiently protected both H9c2 rat cardiomyoblast-derived cells and isolated primary rat cardiomyocytes against hydrogen peroxide-induced mitochondrial and lysosomal dysregulation and cell death. At the same time, BSIH was nontoxic at concentrations up to its solubility limit (600 μM) and in 72-h incubation. Hence, BSIH merits further investigation for prevention and/or treatment of cardiovascular disorders associated with a known (or presumed) component of <span class="hlt">oxidative</span> stress.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25572501','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25572501"><span id="translatedtitle">Role of manganese in protection against <span class="hlt">oxidative</span> stress under <span class="hlt">iron</span> starvation in cyanobacterium Anabaena 7120.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kaushik, Manish Singh; Srivastava, Meenakshi; Verma, Ekta; Mishra, Arun Kumar</p> <p>2015-06-01</p> <p>The cyanobacterium Anabaena sp. PCC 7120 was grown in presence and absence of <span class="hlt">iron</span> to decipher the role of manganese in protection against the <span class="hlt">oxidative</span> stress under <span class="hlt">iron</span> starvation and growth, manganese uptake kinetics, antioxidative enzymes, lipid peroxidation, electrolyte leakage, thiol content, total peroxide, proline and NADH content was investigated. Manganese supported the growth of cyanobacterium Anabaena 7120 under <span class="hlt">iron</span> deprived conditions where maximum uptake rate of manganese was observed with lower K(m) and higher V(max) values. Antioxidative enzymes were also found to be elevated in <span class="hlt">iron</span>-starved conditions. Estimation of lipid peroxidation and electrolyte leakage depicted the role of manganese in stabilizing the integrity of the membrane which was considered as the prime target of oxygen free radicals in <span class="hlt">oxidative</span> stress. The levels of total peroxide, thiol, proline and NADH content, which are the representative of <span class="hlt">oxidative</span> stress response in Anabaena 7120, were also showed increasing trends in <span class="hlt">iron</span> starvation. Hence, the results discerned, clearly suggested the role of manganese in protection against the <span class="hlt">oxidative</span> stress in cyanobacterium Anabaena 7120 under <span class="hlt">iron</span> starvation either due to its antioxidative properties or involvement as cofactor in a number of antioxidative enzymes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4243170','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4243170"><span id="translatedtitle">Comparison of various <span class="hlt">iron</span> chelators and prochelators as protective agents against cardiomyocyte <span class="hlt">oxidative</span> injury</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Jansová, Hana; Macháček, Miloslav; Wang, Qin; Hašková, Pavlína; Jirkovská, Anna; Potůčková, Eliška; Kielar, Filip; Franz, Katherine J.; Šimůnek, Tomáš</p> <p>2014-01-01</p> <p><span class="hlt">Oxidative</span> stress is a common denominator of numerous cardiovascular disorders. Free cellular <span class="hlt">iron</span> catalyzes formation of highly toxic hydroxyl radicals and <span class="hlt">iron</span> chelation may thus be an effective therapeutic approach. However, using classical <span class="hlt">iron</span> chelators in diseases without <span class="hlt">iron</span> overload poses risks that necessitate more advanced approaches, such as prochelators that are activated to chelate <span class="hlt">iron</span> only under disease-specific <span class="hlt">oxidative</span> stress conditions. In this study, three cell membrane-permeable <span class="hlt">iron</span> chelators (clinically-used deferasirox and experimental SIH and HAPI) and five boronate-masked prochelator analogs were evaluated for their ability to protect cardiac cells against <span class="hlt">oxidative</span> injury induced by hydrogen peroxide. Whereas the deferasirox-derived agents TIP and TRA-IMM displayed negligible protection and even considerable toxicity, aroylhydrazone prochelators BHAPI and BSIH-PD provided significant cytoprotection and displayed lower toxicity following prolonged cellular exposure compared to their parent chelators HAPI and SIH, respectively. Overall, the most favorable properties in terms of protective efficiency and low inherent cytotoxicity were observed with aroylhydrazone prochelator BSIH. BSIH efficiently protected both H9c2 rat cardiomyoblast-derived cells as well as isolated primary rat cardiomyocytes against hydrogen peroxide-induced mitochondrial and lysosomal dysregulation and cell death. At the same time, BSIH was non-toxic at concentrations up to its solubility limit (600 µM) and 72-hour incubation. Hence, BSIH merits further investigation for prevention and/or treatment of cardiovascular disorders associated with a known (or presumed) component of <span class="hlt">oxidative</span> stress. PMID:24992833</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/965248','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/965248"><span id="translatedtitle">Synthesis of hybrid gold/<span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles in block copolymer micelles for imaging, drug delivery and magnetic hyperthermia.</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kim, D.-H.; Rozhkova, E. A.; Rajh, T.; Bader, S. D.; Novosad, V.</p> <p>2009-10-01</p> <p>In our study, hybrid gold/<span class="hlt">iron</span> <span class="hlt">oxide</span> loaded thermoresponsive micelles were synthesized for combined hyperthermia and chemotherapy, and optical imaging. Polymeric micelles made of amphiphilic block copolymer of poly(N-isopropylacrylamide-co-acrylamide)-block-poly({var_epsilon}-caprolactone) were conjugated with gold/<span class="hlt">iron</span> <span class="hlt">oxide</span> particles which are self-assembled at the hydrophobic polymer core. Thermal sensitivity and magnetic and optical properties of the hybrid gold/<span class="hlt">iron</span> <span class="hlt">oxide</span> micelles were investigated for the combined therapy and optical imaging.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3847655','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3847655"><span id="translatedtitle">Diet, <span class="hlt">iron</span> biomarkers and <span class="hlt">oxidative</span> stress in a representative sample of Mediterranean population</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p></p> <p>2013-01-01</p> <p>Background The consumption pattern characterized by high consumption of vegetables, fruit, fish, olive oil and red wine has been associated with improvements in the total antioxidant capacity of individuals and reduced incidence of diseases related to <span class="hlt">oxidation</span>. Also, high body <span class="hlt">iron</span> levels may contribute to increase the <span class="hlt">oxidative</span> stress by the generation of reactive oxygen species. The objective of this study is to analyze the relationship between antioxidant and pro-<span class="hlt">oxidant</span> factors obtained from the diet and <span class="hlt">iron</span> biomarkers on lipoprotein <span class="hlt">oxidation</span> and total antioxidant capacity in a representative sample of the Mediterranean population. Methods Cross-sectional prospective study, carried out with 815 randomly selected subjects (425 women and 390 men). Dietary assessment (3-day food records), <span class="hlt">iron</span> biomarkers (serum ferritin, serum <span class="hlt">iron</span> and transferrin saturation), biochemical markers of lipoperoxidation (TBARS), antioxidant capacity (ORAC) and CRP (C-Reactive Protein) were determined. Multiple Linear Regression (MLR) models were applied to analyze the association between diet factors and <span class="hlt">iron</span> biomarkers on TBARS and ORAC levels. Results We observed that lipoperoxidation measured by TBARS increased by age but no differences were observed by sex. Antioxidant capacity measured by ORAC is independent of age and sex. In general, increasing age, tobacco, heme <span class="hlt">iron</span> intake from meat and fish and transferrin saturation were independently and positively associated with TBARS, while non-heme <span class="hlt">iron</span> was negatively associated. Vegetables, vitamin C intake and serum ferritin were positively associated with ORAC, whereas saturated fatty acids and meat intake were negatively associated. Conclusions In our general population, we observed that <span class="hlt">oxidative</span> stress is related to aging, but antioxidant capacity is not. The highest intake of dietary non-heme <span class="hlt">iron</span>, vegetables and vitamin C intake exerts a protective effect against <span class="hlt">oxidation</span> while the highest intake of dietary heme <span class="hlt">iron</span> from</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70020178','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70020178"><span id="translatedtitle"><span class="hlt">Iron</span> and manganese <span class="hlt">oxide</span> mineralization in the Pacific</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Hein, J. R.; Koschinsky, A.; Halbach, P.; Manheim, F. T.; Bau, M.; Jung-Keuk, Kang; Lubick, N.</p> <p>1997-01-01</p> <p><span class="hlt">Iron</span>, manganese, and <span class="hlt">iron</span>-manganese deposits occur in nearly all geomorphologic and tectonic environments in the ocean basins and form by one or more of four processes: (1) hydrogenetic precipitation from cold ambient seawater, (2) precipitation from hydrothermal fluids, (3) precipitation from sediment pore waters that have been modified from bottom water compositions by diagenetic reactions in the sediment column and (4) replacement of rocks and sediment. These processes are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014Nanos...6.9646N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014Nanos...6.9646N"><span id="translatedtitle"><span class="hlt">Iron</span> <span class="hlt">oxide</span> nanoparticles stabilized with dendritic polyglycerols as selective MRI contrast agents</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nordmeyer, Daniel; Stumpf, Patrick; Gröger, Dominic; Hofmann, Andreas; Enders, Sven; Riese, Sebastian B.; Dernedde, Jens; Taupitz, Matthias; Rauch, Ursula; Haag, Rainer; Rühl, Eckart; Graf, Christina</p> <p>2014-07-01</p> <p>Monodisperse small <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles functionalized with dendritic polyglycerol (dPG) or dendritic polyglycerol sulfate (dPGS) are prepared. They are highly stable in aqueous solutions as well as physiological media. In particular, oleic acid capped <span class="hlt">iron</span> <span class="hlt">oxide</span> particles (core diameter = 11 +/- 1 nm) were modified by a ligand exchange process in a one pot synthesis with dPG and dPGS bearing phosphonate as anchor groups. Dynamic light scattering measurements performed in water and different biological media demonstrate that the hydrodynamic diameter of the particles is only slightly increased by the ligand exchange process resulting in a final diameter of less than 30 nm and that the particles are stable in these media. It is also revealed by magnetic resonance studies that their magnetic relaxivity is reduced by the surface modification but it is still sufficient for high contrast magnetic resonance imaging (MRI). Additionally, incubation of dPGS functionalized <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles with human umbilical vein endothelial cells showed a 50% survival at 85 nM (concentration of nanoparticles). Surface plasmon resonance (SPR) studies demonstrate that the dPGS functionalized <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles inhibit L-selectin ligand binding whereas the particles containing only dPG do not show this effect. Experiments in a flow chamber with human myelogenous leukemia cells confirmed L-selectin inhibition of the dPGS functionalized <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles and with that the L-selectin mediated leukocyte adhesion. These results indicate that dPGS functionalized <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles are a promising contrast agent for inflamed tissue probed by MRI.Monodisperse small <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles functionalized with dendritic polyglycerol (dPG) or dendritic polyglycerol sulfate (dPGS) are prepared. They are highly stable in aqueous solutions as well as physiological media. In particular, oleic acid capped <span class="hlt">iron</span> <span class="hlt">oxide</span> particles (core diameter = 11 +/- 1 nm) were modified by a</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_23 --> <div id="page_24" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="461"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140013482','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140013482"><span id="translatedtitle">Risk of <span class="hlt">Oxidative</span> Damage to Bone from Increased <span class="hlt">Iron</span> Stores During Space Flight</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Zwart, S. R.; Smith, S. M.</p> <p>2014-01-01</p> <p><span class="hlt">Iron</span> stores are increased secondary to neocytolysis of red blood cells and a high dietary intake of <span class="hlt">iron</span> during space flight. This raises concerns about the risk of excess <span class="hlt">iron</span> causing <span class="hlt">oxidative</span> damage in many tissues, including bone. Biomarkers of <span class="hlt">iron</span> status, <span class="hlt">oxidative</span> damage, and bone resorption during space flight were analyzed for 23 (16 M/7 F) International Space Station crewmembers as part of the Nutrition SMO project. Up to 5 in-flight blood samples and 24-h urine pools were collected over the course of the 4-6 month missions. Serum <span class="hlt">iron</span> increased slightly during space flight and was decreased at landing (P < 0.0004). An increase in serum ferritin early in flight (217% in women and 68% in men, P < 0.0004), returning to preflight concentrations at landing, and a decrease in transferrin and transferrin receptors during flight indicated that a transient increase in <span class="hlt">iron</span> stores occurred. No inflammatory response was observed during flight. The <span class="hlt">oxidative</span> damage markers 8-hydroxy-2'-deoxyguanosine and prostaglandin F(sub 2(alpha)) were positively correlated (both P < 0.001) with serum ferritin. A greater area under the curve for ferritin during flight was correlated with greater changes in bone mineral density of several bone regions after flight (1). In a separate study (2), a ground-based investigation was conducted that examined the combined effects of radiation exposure and <span class="hlt">iron</span> overload on sensitivity to radiation injury in several physiological systems in 12-wk male Sprague-Dawley rats. The rats were acclimated to an adequate <span class="hlt">iron</span> diet (45 mg <span class="hlt">iron</span> (ferric citrate)/kg diet) for 3 wk and then assigned to one of four groups: adequate <span class="hlt">iron</span> (Fe) diet/no radiation, adequate Fe diet/ radiation, moderately high Fe diet (650 mg Fe (ferric citrate)/kg diet)/no radiation, and moderately high Fe diet/radiation. Animals remained on the assigned diet for 4 wk. Starting on day 14 of experimental diet treatment, animals were exposed to a fractionated dose (0.375 Gy) of Cs</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24016851','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24016851"><span id="translatedtitle">Suppressing <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticle toxicity by vascular targeted antioxidant polymer nanoparticles.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Cochran, David B; Wattamwar, Paritosh P; Wydra, Robert; Hilt, J Zach; Anderson, Kimberly W; Eitel, Richard E; Dziubla, Thomas D</p> <p>2013-12-01</p> <p>The biomedical use of superparamagnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles has been of continued interest in the literature and clinic. Their ability to be used as contrast agents for imaging and/or responsive agents for remote actuation makes them exciting materials for a wide range of clinical applications. Recently, however, concern has arisen regarding the potential health effects of these particles. <span class="hlt">Iron</span> <span class="hlt">oxide</span> toxicity has been demonstrated in in vivo and in vitro models, with <span class="hlt">oxidative</span> stress being implicated as playing a key role in this pathology. One of the key cell types implicated in this injury is the vascular endothelial cells. Here, we report on the development of a targeted polymeric antioxidant, poly(trolox ester), nanoparticle that can suppress <span class="hlt">oxidative</span> damage. As the polymer undergoes enzymatic hydrolysis, active trolox is locally released, providing a long term protection against pro-<span class="hlt">oxidant</span> agents. In this work, poly(trolox) nanoparticles are targeted to platelet endothelial cell adhesion molecules (PECAM-1), which are able to bind to and internalize in endothelial cells and provide localized protection against the cytotoxicity caused by <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles. These results indicate the potential of using poly(trolox ester) as a means of mitigating <span class="hlt">iron</span> <span class="hlt">oxide</span> toxicity, potentially expanding the clinical use and relevance of these exciting systems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24372096','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24372096"><span id="translatedtitle">Methanogenesis affected by the co-occurrence of <span class="hlt">iron</span>(III) <span class="hlt">oxides</span> and humic substances.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhou, Shungui; Xu, Jielong; Yang, Guiqin; Zhuang, Li</p> <p>2014-04-01</p> <p><span class="hlt">Iron</span> <span class="hlt">oxides</span> and humic substances (humics) have substantial effects on biochemical processes, such as methanogenesis, due to their redox reactivity and ubiquitous presence. This study aimed to investigate how methanogenesis is affected by the common occurrence of these compounds, which has not been considered to date. The experiment was conducted with anoxic paddy soil microcosms receiving a humics surrogate compound (anthraquinone-2,6-disulfonate, AQDS) and three <span class="hlt">iron</span>(III) <span class="hlt">oxides</span> (ferrihydrite, hematite, and magnetite) differing in crystallinity and conductivity. Ferrihydrite suppressed methanogenesis, whereas AQDS, hematite, and magnetite facilitated methanogenesis. CH4 production in co-occurring ferrihydrite + AQDS, hematite + AQDS, and magnetite + AQDS cultures was 4.1, 1.3, and 0.9 times greater than the corresponding cultures without AQDS, respectively. Syntrophic cooperation between Geobacter and Methanosarcina occurred in the methanogenesis-facilitated cultures. Experimental results suggested that the conductive characteristics of <span class="hlt">iron</span>(III) <span class="hlt">oxides</span> was an important factor determining the methanogenic response to the co-occurrence of <span class="hlt">iron</span>(III) <span class="hlt">oxides</span> and humics in anaerobic paddy soil. This work indicated that the type of <span class="hlt">iron</span>(III) <span class="hlt">oxides</span> may significantly affect carbon cycling under anoxic conditions in natural wetlands.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23528010','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23528010"><span id="translatedtitle">Three-dimensionally ordered macroporous <span class="hlt">iron</span> <span class="hlt">oxide</span> for removal of H2S at medium temperatures.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Fan, Hui-Ling; Sun, Ting; Zhao, Yan-Peng; Shangguan, Ju; Lin, Jian-Ying</p> <p>2013-05-01</p> <p>A series of <span class="hlt">iron</span> <span class="hlt">oxide</span> sorbents with novel structures of three-dimensionally ordered macropores (3DOM), ranging in size from 60 to 550 nm, were fabricated and creatively used as sorbents for the removal of H2S at medium temperatures of 300-350 °C. Evaluation tests using thermogravimetric analysis (TGA) and a fixed-bed reactor showed that, in comparison to the <span class="hlt">iron</span> <span class="hlt">oxide</span> sorbent prepared by a conventional mixing method, the fabricated <span class="hlt">iron</span> <span class="hlt">oxide</span> sorbent with a 3DOM structure exhibited much higher reactivity and efficiency, as well as high sorbent utilization with low regeneration temperature. The excellent performance of 3DOM <span class="hlt">iron</span> <span class="hlt">oxide</span> as a sulfur sorbent is attributed to its special texture, i.e., the open and interconnected macroporous, large surface area, and nanoparticles of <span class="hlt">iron</span> <span class="hlt">oxide</span>, which are revealed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and nitrogen adsorption techniques. The investigation results of the pore effect on the performance of the sorbent show that sorbents with pores size around 150 nm in diameter revealed the best performance. The reason is that pores of this size are large enough to allow gas to pass through even if the channel is partially blocked during the reaction process while remaining a large surface area that can provide more active sites for the reaction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25413115','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25413115"><span id="translatedtitle">Recycling of a spent <span class="hlt">iron</span> based catalyst for the complete <span class="hlt">oxidation</span> of toluene: effect of palladium.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kim, Sang Chai; Nah, Jae Woon</p> <p>2015-01-01</p> <p>Complete <span class="hlt">oxidation</span> of volatile organic compound (toluene) was carried out to assess the property and activity of the palladium-spent <span class="hlt">iron</span> based catalyst. The properties of the prepared catalysts were characterized by using the Brunauer-Emmett-Teller method and by conducting temperature-programmed reduction, X-ray diffraction, X-ray photoelectron spectroscopy and field emission transmission electron microscopy. The addition of palladium to the spent <span class="hlt">iron</span> based catalyst pretreated with oxalic acid shifted the conversion curve for the total <span class="hlt">oxidation</span> of toluene to lower temperature. An increase in the toluene conversion due to palladium was highly related to the easier lattice oxygen mobility of the catalysts. Instrumental analysis suggested the presence of a strong interaction between palladium and <span class="hlt">iron</span> <span class="hlt">oxide</span> species. Moreover, in the case of reducing the Pd/Fe catalyst with hydrogen, palladium accelerated the reducing <span class="hlt">iron</span> <span class="hlt">oxides</span>, subsequently decreasing the toluene conversion. As a result, the <span class="hlt">oxidation</span> states of palladium and <span class="hlt">iron</span> had an important effect on the catalytic activity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2008Nanot..19F5608Z&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2008Nanot..19F5608Z&link_type=ABSTRACT"><span id="translatedtitle">Preparation and characterization of thermosensitive PNIPAA-coated <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, Shengmao; Zhang, Linna; He, Benfang; Wu, Zhishen</p> <p>2008-08-01</p> <p>A new and facile approach was established to fabricate thermoresponsive poly(N-isopropylacrylamide) (PNIPAA) coated <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles in a non-aqueous medium. The morphology and structure of the nanoparticle-doped composite were analyzed by means of transmission electron microscopy (TEM), x-ray powder diffraction (XRD), and Fourier transformation infrared spectrometry (FTIR). The thermosensitivity of the composite was also investigated. Results indicated that the oil-soluble <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles encapsulated with PNIPAA, composed of an inorganic <span class="hlt">iron</span> <span class="hlt">oxide</span> core and biocompatible PNIPAA shell, were dispersed well in water and had a sphere-like shape. The PNIPAA-coated <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles with such a kind of core-shell structure showed excellent thermosensitivity. Namely, the aqueous suspension of PNIPAA-coated <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles dramatically changed from transparent to opaque as the temperature increased from room temperature to 38 °C, showing potential as optical transmittance switch materials and their significance in the fields of protein adsorption and purification controlled release, and drug delivery.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24375902','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24375902"><span id="translatedtitle">New carboxysilane-coated <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles for nonspecific cell labelling.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bridot, Jean-Luc; Stanicki, Dimitri; Laurent, Sophie; Boutry, Sébastien; Gossuin, Yves; Leclère, Philippe; Lazzaroni, Roberto; Vander Elst, Luce; Muller, Robert N</p> <p>2013-01-01</p> <p>Magnetic resonance imaging (MRI) offers the possibility of tracking cells labelled with a contrast agent and evaluating the progress of cell therapies. This requires efficient cell labelling with contrast agents. A basic incubation of cells with <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles (NPs) is a common method. This study reports the synthesis at the gram scale of <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles as MRI T₂ contrast agents for cell labelling. These NPs are based on small <span class="hlt">iron</span> <span class="hlt">oxide</span> cores coated with a thin polysiloxane shell presenting carboxylic acid functions. The <span class="hlt">iron</span> <span class="hlt">oxide</span> cores produced have been characterized by transmission electron microscopy, X-ray diffraction, ζ-potential, infrared, photon correlation spectroscopy, atomic force microscopy, magnetometry and relaxometric measurements. These measurements confirmed the expected surface modification by carboxysilane. Carboxylic groups created electrostatic repulsion between NPs when they are deprotonated. Therefore, highly concentrated aqueous solutions of carboxysilane coated <span class="hlt">iron</span> <span class="hlt">oxide</span> NPs can be obtained, up to 70% (w/w). These NPs could be used for cell labelling owing to their aggregation and re-dispersion properties. NPs precipitated in Dulbecco's modified Eagle medium induced a rapid association with 3 T6 fibroblast cells and could easily be re-dispersed in phosphate buffer saline solution to obtain properly labelled cells. PMID:24375902</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/983142','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/983142"><span id="translatedtitle">Structural and Morphological Features of Concentric <span class="hlt">Iron</span> <span class="hlt">Oxide</span>/Carbon Nanotubes Obtained from Phospholipids</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Yu, Min; Howe, Jane Y; Jeong, Kyunghoon; Shim, Inbo; Kim, Woochul; Kim, Chulsung; Ahn, Jaepyoung; Lee, Jaegab; Urban, Mark W.</p> <p>2010-01-01</p> <p>Biologically active 1,2-bis(10,12-tricosadiynoyl)-sn-glycero-3-phosphocholine (DC{sub 8,9}PC) nanotube-forming phospholipids (PLs) have been utilized as templates to prepare ferromagnetic nanotubes (FMNTs). Combining X-ray diffraction (XRD), selected area electron diffraction (SAD), high-resolution transmission electron microscopy (HRTEM), Raman, and Moessbauer spectroscopy measurements, FMNTs morphological features and chemical composition were determined. These studies showed that FMNTs consist of <span class="hlt">iron</span> <span class="hlt">oxide/carbon/iron</span> <span class="hlt">oxide</span> concentric nanotubes with the amorphous carbon phase sandwiched between two <span class="hlt">iron</span> <span class="hlt">oxide</span> layers. The <span class="hlt">iron</span> <span class="hlt">oxide</span> phase consists of nanocrystalline magnetite (Fe{sub 3}O{sub 4}) which coexist as tetrahedral Fe{sup 3+} and octahedral Fe{sup 2.5+} sites containing minute quantities of hematite ({alpha}-Fe{sub 2}O{sub 3}) phase. The carbon phase consists of amorphous carbon forming an amorphous carbon nanotube (ACNT). Magnetic measurements showed that saturation magnetization (M{sub s}) of FMNTs is 79 emu/g, but upon removal of the <span class="hlt">iron</span> <span class="hlt">oxide</span> outer and inner layers, ACNTs become paramagnetic. The electrical resistivity ({rho}) of single FMNT is 3.3 x 10{sup -2} {Omega} {center_dot} m, which decreases to 5.06 x 10{sup -4} {Omega} {center_dot} m for ACNT. These magneto-electric properties can be easily tailored, depending upon desired applications and needs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23528010','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23528010"><span id="translatedtitle">Three-dimensionally ordered macroporous <span class="hlt">iron</span> <span class="hlt">oxide</span> for removal of H2S at medium temperatures.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Fan, Hui-Ling; Sun, Ting; Zhao, Yan-Peng; Shangguan, Ju; Lin, Jian-Ying</p> <p>2013-05-01</p> <p>A series of <span class="hlt">iron</span> <span class="hlt">oxide</span> sorbents with novel structures of three-dimensionally ordered macropores (3DOM), ranging in size from 60 to 550 nm, were fabricated and creatively used as sorbents for the removal of H2S at medium temperatures of 300-350 °C. Evaluation tests using thermogravimetric analysis (TGA) and a fixed-bed reactor showed that, in comparison to the <span class="hlt">iron</span> <span class="hlt">oxide</span> sorbent prepared by a conventional mixing method, the fabricated <span class="hlt">iron</span> <span class="hlt">oxide</span> sorbent with a 3DOM structure exhibited much higher reactivity and efficiency, as well as high sorbent utilization with low regeneration temperature. The excellent performance of 3DOM <span class="hlt">iron</span> <span class="hlt">oxide</span> as a sulfur sorbent is attributed to its special texture, i.e., the open and interconnected macroporous, large surface area, and nanoparticles of <span class="hlt">iron</span> <span class="hlt">oxide</span>, which are revealed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and nitrogen adsorption techniques. The investigation results of the pore effect on the performance of the sorbent show that sorbents with pores size around 150 nm in diameter revealed the best performance. The reason is that pores of this size are large enough to allow gas to pass through even if the channel is partially blocked during the reaction process while remaining a large surface area that can provide more active sites for the reaction. PMID:23528010</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=202013','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=202013"><span id="translatedtitle">Anaerobic <span class="hlt">oxidation</span> of ferrous <span class="hlt">iron</span> by purple bacteria, a new type of phototrophic metabolism.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Ehrenreich, A; Widdel, F</p> <p>1994-01-01</p> <p>Anoxic <span class="hlt">iron</span>-rich sediment samples that had been stored in the light showed development of brown, rusty patches. Subcultures in defined mineral media with ferrous <span class="hlt">iron</span> (10 mmol/liter, mostly precipitated as FeCO3) yielded enrichments of anoxygenic phototrophic bacteria which used ferrous <span class="hlt">iron</span> as the sole electron donor for photosynthesis. Two different types of purple bacteria, represented by strains L7 and SW2, were isolated which <span class="hlt">oxidized</span> colorless ferrous <span class="hlt">iron</span> under anoxic conditions in the light to brown ferric <span class="hlt">iron</span>. Strain L7 had rod-shaped, nonmotile cells (1.3 by 2 to 3 microns) which frequently formed gas vesicles. In addition to ferrous <span class="hlt">iron</span>, strain L7 used H2 + CO2, acetate, pyruvate, and glucose as substrate for phototrophic growth. Strain SW2 had small rod-shaped, nonmotile cells (0.5 by 1 to 1.5 microns). Besides ferrous <span class="hlt">iron</span>, strain SW2 utilized H2 + CO2, monocarboxylic acids, glucose, and fructose. Neither strain utilized free sulfide; however, both strains grew on black ferrous sulfide (FeS) which was converted to ferric <span class="hlt">iron</span> and sulfate. Strains L7 and SW2 grown photoheterotrophically without ferrous <span class="hlt">iron</span> were purple to brownish red and yellowish brown, respectively; absorption spectra revealed peaks characteristic of bacteriochlorophyll a. The closest phototrophic relatives of strains L7 and SW2 so far examined on the basis of 16S rRNA sequences were species of the genera Chromatium (gamma subclass of proteobacteria) and Rhodobacter (alpha subclass), respectively. In mineral medium, the new isolates formed 7.6 g of cell dry mass per mol of Fe(II) <span class="hlt">oxidized</span>, which is in good agreement with a photoautotrophic utilization of ferrous <span class="hlt">iron</span> as electron donor for CO2 fixation. Dependence of ferrous <span class="hlt">iron</span> <span class="hlt">oxidation</span> on light and CO2 was also demonstrated in dense cell suspensions. In media containing both ferrous <span class="hlt">iron</span> and an organic substrate (e.g., acetate, glucose), strain L7 utilized ferrous <span class="hlt">iron</span> and the organic compound simultaneously; in contrast, strain</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24524675','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24524675"><span id="translatedtitle">Tuning reactivity and mechanism in <span class="hlt">oxidation</span> reactions by mononuclear nonheme <span class="hlt">iron</span>(IV)-oxo complexes.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Nam, Wonwoo; Lee, Yong-Min; Fukuzumi, Shunichi</p> <p>2014-04-15</p> <p>Mononuclear nonheme <span class="hlt">iron</span> enzymes generate high-valent <span class="hlt">iron</span>(IV)-oxo intermediates that effect metabolically important <span class="hlt">oxidative</span> transformations in the catalytic cycle of dioxygen activation. In 2003, researchers first spectroscopically characterized a mononuclear nonheme <span class="hlt">iron</span>(IV)-oxo intermediate in the reaction of taurine: α-ketogultarate dioxygenase (TauD). This nonheme <span class="hlt">iron</span> enzyme with an <span class="hlt">iron</span> active center was coordinated to a 2-His-1- carboxylate facial triad motif. In the same year, researchers obtained the first crystal structure of a mononuclear nonheme <span class="hlt">iron</span>(IV)-oxo complex bearing a macrocyclic supporting ligand, [(TMC)Fe(IV)(O)](2+) (TMC = 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecene), in studies that mimicked the biological enzymes. With these breakthrough results, many other studies have examined mononuclear nonheme <span class="hlt">iron</span>(IV)-oxo intermediates trapped in enzymatic reactions or synthesized in biomimetic reactions. Over the past decade, researchers in the fields of biological, bioinorganic, and <span class="hlt">oxidation</span> chemistry have extensively investigated the structure, spectroscopy, and reactivity of nonheme <span class="hlt">iron</span>(IV)-oxo species, leading to a wealth of information from these enzymatic and biomimetic studies. This Account summarizes the reactivity and mechanisms of synthetic mononuclear nonheme <span class="hlt">iron</span>(IV)-oxo complexes in <span class="hlt">oxidation</span> reactions and examines factors that modulate their reactivities and change their reaction mechanisms. We focus on several reactions including the <span class="hlt">oxidation</span> of organic and inorganic compounds, electron transfer, and oxygen atom exchange with water by synthetic mononuclear nonheme <span class="hlt">iron</span>(IV)-oxo complexes. In addition, we recently observed that the C-H bond activation by nonheme <span class="hlt">iron</span>(IV)-oxo and other nonheme metal(IV)-oxo complexes does not follow the H-atom abstraction/oxygen-rebound mechanism, which has been well-established in heme systems. The structural and electronic effects of supporting ligands on the <span class="hlt">oxidizing</span> power of <span class="hlt">iron</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3697272','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3697272"><span id="translatedtitle">Deposition of Biogenic <span class="hlt">Iron</span> Minerals in a Methane <span class="hlt">Oxidizing</span> Microbial Mat</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Wrede, Christoph; Dreier, Anne; Heller, Christina; Reitner, Joachim; Hoppert, Michael</p> <p>2013-01-01</p> <p>The syntrophic community between anaerobic methanotrophic archaea and sulfate reducing bacteria forms thick, black layers within multi-layered microbial mats in chimney-like carbonate concretions of methane seeps located in the Black Sea Crimean shelf. The microbial consortium conducts anaerobic <span class="hlt">oxidation</span> of methane, which leads to the formation of mainly two biomineral by-products, calcium carbonates and <span class="hlt">iron</span> sulfides, building up these chimneys. <span class="hlt">Iron</span> sulfides are generated by the microbial reduction of <span class="hlt">oxidized</span> sulfur compounds in the microbial mats. Here we show that sulfate reducing bacteria deposit biogenic <span class="hlt">iron</span> sulfides extra- and intracellularly, the latter in magnetosome-like chains. These chains appear to be stable after cell lysis and tend to attach to cell debris within the microbial mat. The particles may be important nuclei for larger <span class="hlt">iron</span> sulfide mineral aggregates. PMID:23843725</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/15105257','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/15105257"><span id="translatedtitle">Heme oxygenase-1: transducer of pathological brain <span class="hlt">iron</span> sequestration under <span class="hlt">oxidative</span> stress.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Schipper, Hyman M</p> <p>2004-03-01</p> <p>Mechanisms responsible for the pathological deposition of redox-active brain <span class="hlt">iron</span> in human neurological disorders remain incompletely understood. Heme oxygenase-1 (HO-1) is a 32-kDa stress protein that degrades heme to biliverdin, free <span class="hlt">iron</span>, and carbon monoxide. In this chapter, we review evidence that (1) HO-1 is overexpressed in CNS tissues affected by Alzheimer's disease (AD), Parkinson's disease (PD), multiple sclerosis (MS), and other degenerative and nondegenerative CNS diseases; (2) the pro-<span class="hlt">oxidant</span> effects of dopamine, hydrogen peroxide, beta-amyloid, and proinflammatory cytokines stimulate HO-1 expression in some of these conditions; and (3) upregulation of HO-1 in astrocytes exacerbates intracellular <span class="hlt">oxidative</span> stress and promotes sequestration of nontransferrin-derived <span class="hlt">iron</span> by the mitochondrial compartment. A model is presented implicating glial HO-1 induction as a "final common pathway" leading to pathological <span class="hlt">iron</span> sequestration and mitochondrial insufficiency in a host of human CNS disorders.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25249246','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25249246"><span id="translatedtitle">Effect of <span class="hlt">iron</span> <span class="hlt">oxide</span> loading on magnetoferritin structure in solution as revealed by SAXS and SANS.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Melníková, L; Petrenko, V I; Avdeev, M V; Garamus, V M; Almásy, L; Ivankov, O I; Bulavin, L A; Mitróová, Z; Kopčanský, P</p> <p>2014-11-01</p> <p>Synthetic biological macromolecule of magnetoferritin containing an <span class="hlt">iron</span> <span class="hlt">oxide</span> core inside a protein shell (apoferritin) is prepared with different content of <span class="hlt">iron</span>. Its structure in aqueous solution is analysed by small-angle synchrotron X-ray (SAXS) and neutron (SANS) scattering. The loading factor (LF) defined as the average number of <span class="hlt">iron</span> atoms per protein is varied up to LF=800. With an increase of the LF, the scattering curves exhibit a relative increase in the total scattered intensity, a partial smearing and a shift of the match point in the SANS contrast variation data. The analysis shows an increase in the polydispersity of the proteins and a corresponding effective increase in the relative content of magnetic material against the protein moiety of the shell with the LF growth. At LFs above ∼150, the apoferritin shell undergoes structural changes, which is strongly indicative of the fact that the shell stability is affected by <span class="hlt">iron</span> <span class="hlt">oxide</span> presence.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013MMTB...44.1000S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013MMTB...44.1000S"><span id="translatedtitle">Study of Organic and Inorganic Binders on Strength of <span class="hlt">Iron</span> <span class="hlt">Oxide</span> Pellets</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Srivastava, Urvashi; Kawatra, S. Komar; Eisele, Timothy C.</p> <p>2013-08-01</p> <p>Bentonite is a predominant binder used in <span class="hlt">iron</span> ore pelletization. However, the presence of a high content of silica and alumina in bentonite is considered undesirable for ironmaking operations. The objective of this study was to identify the alternatives of bentonite for <span class="hlt">iron</span> ore pelletization. To achieve this goal, different types of organic and inorganic binders were utilized to produce <span class="hlt">iron</span> <span class="hlt">oxide</span> pellets. The quality of these <span class="hlt">iron</span> <span class="hlt">oxide</span> pellets was compared with pellets made using bentonite. All pellets were tested for physical strength at different stages of pelletization to determine their ability to survive during shipping and handling. The results show that organic binders such as lactose monohydrate, hemicellulose, and sodium lignosulfonate can provide sufficient strength to indurated pellets.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/10504049','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/10504049"><span id="translatedtitle">'NC100150', a preparation of <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles ideal for positive-contrast MR angiography.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kellar, K E; Fujii, D K; Gunther, W H; Briley-Saebø, K; Spiller, M; Koenig, S H</p> <p>1999-08-01</p> <p>A laboratory-scale synthesis of NC100150 (<span class="hlt">iron</span> <span class="hlt">oxide</span> particles with an <span class="hlt">oxidized</span> starch coating) was characterized by magnetization measurements (vibrating sample magnetometry, VSM), relaxometry (1/T1 NMRD profiles and 1/T2 at 10 and 20 MHz), and dynamic light scattering (photon correlation spectroscopy, PCS). The results were related to give a self-consistent physical description of the particles: a water-impenetrable part making up 12% of the total particle volume, 82% of this volume consisting of an <span class="hlt">iron</span> <span class="hlt">oxide</span> core and the remaining 18% consisting of an <span class="hlt">oxidized</span> starch rind; and, a water-penetrable part making up 88% of the total particle volume, consisting of <span class="hlt">oxidized</span> starch polymers and entrained water molecules. Relating the magnetization to the relaxometry results required that the <span class="hlt">oxidized</span> starch coating slows the diffusivity of solvent water molecules in the vicinity of the <span class="hlt">iron</span> <span class="hlt">oxide</span> cores. The effect of the organic coating on water diffusivity, not previously considered in the application of relaxation theory to <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles, is supported by the much greater (factor of about 2) diameter obtained from the dynamic light scattering measurements in comparison to that obtained from the magnetization measurements. The present work shows that three physical techniques--VSM, relaxometry, and PCS--are needed for properly assessing <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles for use as contrast agents for magnetic resonance angiography (MRA). It is also shown that NC100150 has a narrow range of diameters and the smallest value of r2/r1 reported to date, an asset for MRA. PMID:10504049</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26430718','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26430718"><span id="translatedtitle"><span class="hlt">Iron</span> Catalyzed Dual-<span class="hlt">Oxidative</span> Dehydrogenative (DOD) Tandem Annulation of Glycine Derivatives with Tetrahydrofurans.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Huo, Congde; Chen, Fengjuan; Yuan, Yong; Xie, Haisheng; Wang, Yajun</p> <p>2015-10-16</p> <p>A novel <span class="hlt">iron</span>-catalyzed dual-<span class="hlt">oxidative</span> dehydrogenative (DOD) tandem annulation of glycine derivatives with tetrahydrofurans (THFs) for the synthesis of high value quinoline fused lactones has been developed. The reactions were performed under mild reaction conditions. And the use of cheap substrates (glycine derivatives and THF) and an even cheaper simple inorganic <span class="hlt">iron</span> salt as the catalyst makes this protocol very attractive for potential synthetic applications. PMID:26430718</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/15655997','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/15655997"><span id="translatedtitle">Nitric <span class="hlt">oxide</span> formation in an <span class="hlt">iron</span> <span class="hlt">oxide</span> pellet rotary kiln furnace.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Davis, R A</p> <p>1998-01-01</p> <p>A one-dimensional numerical model was developed to simulate the effects of heat and mass transfer on the formation of <span class="hlt">oxides</span> of nitrogen (NOx) in a rotary kiln furnace for <span class="hlt">iron</span> <span class="hlt">oxide</span> pellet induration. The modeled kiln has a length-to-diameter ratio of approximately seven. The principal mechanism of heat transfer is radiation from the flame, which was described by the net radiation method. The well known Zeldovich mechanism was used to predict thermal NOx generation. Temperature fluctuations in the vicinity of the flame were estimated with a clipped Gaussian probability density function. The thermal energy and mass balance model equations were solved numerically. The model is capable of predicting temperature profiles and NOx production rates in agreement with observed plant performance. The model was used to explore the effects of process changes on the total NOx formation in the kiln. It was concluded that the gas temperature as well as the partial pressure of oxygen in the process gases controls the rate of NOx formation. Lowering the temperature of the kiln gases by increasing the secondary air flow rates requires simultaneously decreasing the pellet production rate in order to maintain the pellet temperatures needed for blast furnace conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2601529','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2601529"><span id="translatedtitle">Increased RNA <span class="hlt">oxidative</span> damage and <span class="hlt">iron</span> content in skeletal muscle with aging and disuse atrophy</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Hofer, Tim; Marzetti, Emanuele; Xu, Jinze; Seo, Arnold Y.; Gulec, Sukru; Knutson, Mitchell D.; Leeuwenburgh, Christiaan; Dupont-Versteegden, Esther E.</p> <p>2008-01-01</p> <p>Muscle atrophy with aging or disuse is associated with deregulated <span class="hlt">iron</span> homeostasis and increased <span class="hlt">oxidative</span> stress likely inflicting damage to nucleic acids. Therefore, we investigated RNA and DNA <span class="hlt">oxidation</span>, and <span class="hlt">iron</span> homeostasis in gastrocnemius muscles. Disuse atrophy was induced in 6- and 32-month old male Fischer 344/Brown Norway rats by 14 days of hind limb suspension (HS). We show that RNA, but not DNA, <span class="hlt">oxidative</span> damage increased 85% with age and 36% with HS in aged muscle. Additionally, non-heme <span class="hlt">iron</span> levels increased 233% with aging and 83% with HS at old age, while staining for free <span class="hlt">iron</span> was strongest in the smallest fibers. Simultaneously, the mRNA abundance of transferrin receptor-1 decreased by 80% with age and 48% with HS for young animals, while that of the hepcidin regulator hemojuvelin decreased 37% with age, but increased about 44% with disuse, indicating a dysregulation of <span class="hlt">iron</span> homeostasis favoring increased intracellular free <span class="hlt">iron</span> in atrophied muscles. RNA and DNA concentrations increased with age and were negatively correlated with muscle mass, whereas protein concentrations decreased with aging, indicating a preferential loss of protein compared to nucleic acids. Furthermore, xanthine oxidase activity increased with age, but not with HS, while mRNA abundance of the Y box-binding protein-1, which has been suggested to bind <span class="hlt">oxidized</span> RNA, did not change with age or HS. These results suggest that RNA <span class="hlt">oxidation</span>, possibly mediated by increased non-heme <span class="hlt">iron</span>, might contribute to muscle atrophy due to disuse particularly in aged muscle. PMID:18395385</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19248516','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19248516"><span id="translatedtitle">[Determination of amorphous <span class="hlt">iron</span> <span class="hlt">oxides</span> in soil by hydroxylamine extraction-spectrophotometry].</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Chi, Guang-yu; Zhang, Zhao-wei; Chen, Xin; Shi, Yi</p> <p>2008-12-01</p> <p>Amorphous <span class="hlt">iron</span> <span class="hlt">oxides</span> in soil were determined by hydroxylamine extraction-spectrophotometry. The results showed that hydroxylamrnine extraction eliminates interference of magnetite and the defect of results being on the high side was overcome to a certain degree compared with oxalic acid-oxalic acid ammonium extraction. The hydroxylamine extraction-spectrophotometry for the detection of amorphous <span class="hlt">iron</span> <span class="hlt">oxides</span> in soil was highly precise (relative standard deviation was less than 2.0%) and highly reliable (recovery rates ranged from 97.5% to 101.5%). Other advantages of the method were rapidness,simplicity and a shorter chromogenic time. In addition, soil incubated anaerobically at constant temperature under laboratory condition was investigated. The results suggested that <span class="hlt">iron</span> reduction rates during initiation, rapid reaction and steady phases in the soil samples anaerobic incubation were 0.030-0.053, 0.186-0.333 and 0.015-0.030 g x d(-1) x kg(-1), respectively. Significant relationship between the concentrations of hydroxylamine extraction <span class="hlt">iron</span> and <span class="hlt">iron</span> reduction rates during rapid reaction phase in soil incubation (r= 0.9907, p<0.01) indicated that hydroxylamine had a higher degree of selectivity in amorphous <span class="hlt">iron</span> <span class="hlt">oxides</span> extraction than oxalic acid-oxalic acid ammonium extraction.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_24 --> <div id="page_25" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="481"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JNuM..448..420T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JNuM..448..420T"><span id="translatedtitle">Advanced <span class="hlt">oxidation</span>-resistant <span class="hlt">iron</span>-based alloys for LWR fuel cladding</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Terrani, K. A.; Zinkle, S. J.; Snead, L. L.</p> <p>2014-05-01</p> <p>Application of advanced <span class="hlt">oxidation</span>-resistant <span class="hlt">iron</span> alloys as light water reactor fuel cladding is proposed. The motivations are based on specific limitations associated with zirconium alloys, currently used as fuel cladding, under design-basis and beyond-design-basis accident scenarios. Using a simplified methodology, gains in safety margins under severe accidents upon transition to advanced <span class="hlt">oxidation</span>-resistant <span class="hlt">iron</span> alloys as fuel cladding are showcased. <span class="hlt">Oxidation</span> behavior, mechanical properties, and irradiation effects of advanced <span class="hlt">iron</span> alloys are briefly reviewed and compared to zirconium alloys as well as historic austenitic stainless steel cladding materials. Neutronic characteristics of <span class="hlt">iron</span>-alloy-clad fuel bundles are determined and fed into a simple economic model to estimate the impact on nuclear electricity production cost. Prior experience with steel cladding is combined with the current understanding of the mechanical properties and irradiation behavior of advanced <span class="hlt">iron</span> alloys to identify a combination of cladding thickness reduction and fuel enrichment increase (∼0.5%) as an efficient route to offset any penalties in cycle length, due to higher neutron absorption in the <span class="hlt">iron</span> alloy cladding, with modest impact on the economics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26863929','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26863929"><span id="translatedtitle">Review of the Evidence from Epidemiology, Toxicology, and Lung Bioavailability on the Carcinogenicity of Inhaled <span class="hlt">Iron</span> <span class="hlt">Oxide</span> Particulates.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Pease, Camilla; Rücker, Thomas; Birk, Thomas</p> <p>2016-03-21</p> <p>Since the <span class="hlt">iron</span>-age and throughout the industrial age, humans have been exposed to <span class="hlt">iron</span> <span class="hlt">oxides</span>. Here, we review the evidence from epidemiology, toxicology, and lung bioavailability as to whether <span class="hlt">iron</span> <span class="hlt">oxides</span> are likely to act as human lung carcinogens. Current evidence suggests that observed lung tumors in rats result from a generic particle overload effect and local inflammation that is rat-specific under the dosing conditions of intratracheal instillation. This mode of action therefore, is not relevant to human exposure. However, there are emerging differences seen in vitro, in cell uptake and cell bioavailability between "bulk" <span class="hlt">iron</span> <span class="hlt">oxides</span> and "nano" <span class="hlt">iron</span> <span class="hlt">oxides</span>. "Bulk" particulates, as defined here, are those where greater than 70% are >100 nm in diameter. Similarly, "nano" <span class="hlt">iron</span> <span class="hlt">oxides</span> are defined in this context as particulates where the majority, usually >95% for pure engineered forms of primary particulates (not agglomerates), fall in the range 1-100 nm in diameter. From the weight of scientific evidence, "bulk" <span class="hlt">iron</span> <span class="hlt">oxides</span> are not genotoxic/mutagenic. Recent evidence for "nano" <span class="hlt">iron</span> <span class="hlt">oxide</span> is conflicting regarding genotoxic potential, albeit genotoxicity was not observed in an in vivo acute oral dose study, and "nano" <span class="hlt">iron</span> <span class="hlt">oxides</span> are considered safe and are being investigated for biomedical uses; there is no specific in vivo genotoxicity study on "nano" <span class="hlt">iron</span> <span class="hlt">oxides</span> via inhalation. Some evidence is available that suggests, hypothetically due to the larger surface area of "nano" <span class="hlt">iron</span> <span class="hlt">oxide</span> particulates, that toxicity could be exerted via the generation of reactive oxygen species (ROS) in the cell. However, the potential for ROS generation as a basis for explaining rodent tumorigenicity is only apparent if free <span class="hlt">iron</span> from intracellular "nano" scale <span class="hlt">iron</span> <span class="hlt">oxide</span> becomes bioavailable at significant levels inside the cell. This would not be expected from "bulk" <span class="hlt">iron</span> <span class="hlt">oxide</span> particulates. Furthermore, human epidemiological evidence from a number of studies suggests that</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/22363331','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/22363331"><span id="translatedtitle">Toward a mechanistic understanding of anaerobic nitrate-dependent <span class="hlt">iron</span> <span class="hlt">oxidation</span>: balancing electron uptake and detoxification.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Carlson, Hans K; Clark, Iain C; Melnyk, Ryan A; Coates, John D</p> <p>2012-01-01</p> <p>The anaerobic <span class="hlt">oxidation</span> of Fe(II) by subsurface microorganisms is an important part of biogeochemical cycling in the environment, but the biochemical mechanisms used to couple <span class="hlt">iron</span> <span class="hlt">oxidation</span> to nitrate respiration are not well understood. Based on our own work and the evidence available in the literature, we propose a mechanistic model for anaerobic nitrate-dependent <span class="hlt">iron</span> <span class="hlt">oxidation</span>. We suggest that anaerobic <span class="hlt">iron-oxidizing</span> microorganisms likely exist along a continuum including: (1) bacteria that inadvertently <span class="hlt">oxidize</span> Fe(II) by abiotic or biotic reactions with enzymes or chemical intermediates in their metabolic pathways (e.g., denitrification) and suffer from toxicity or energetic penalty, (2) Fe(II) tolerant bacteria that gain little or no growth benefit from <span class="hlt">iron</span> <span class="hlt">oxidation</span> but can manage the toxic reactions, and (3) bacteria that efficiently accept electrons from Fe(II) to gain a growth advantage while preventing or mitigating the toxic reactions. Predictions of the proposed model are highlighted and experimental approaches are discussed. PMID:22363331</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21126142','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21126142"><span id="translatedtitle">Reduction of <span class="hlt">iron-oxide</span>-carbon composites: part I. Estimation of the rate constants</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Halder, S.; Fruehan, R.J.</p> <p>2008-12-15</p> <p>A new ironmaking concept using <span class="hlt">iron-oxide</span>-carbon composite pellets has been proposed, which involves the combination of a rotary hearth furnace (RHF) and an <span class="hlt">iron</span> bath smelter. This part of the research focuses on studying the two primary chemical kinetic steps. Efforts have been made to experimentally measure the kinetics of the carbon gasification by CO{sub 2} and wustite reduction by CO by isolating them from the influence of heat- and mass-transport steps. A combined reaction model was used to interpret the experimental data and determine the rate constants. Results showed that the reduction is likely to be influenced by the chemical kinetics of both carbon <span class="hlt">oxidation</span> and wustite reduction at the temperatures of interest. Devolatilized wood-charcoal was observed to be a far more reactive form of carbon in comparison to coal-char. Sintering of the <span class="hlt">iron-oxide</span> at the high temperatures of interest was found to exert a considerable influence on the reactivity of wustite by virtue of altering the internal pore surface area available for the reaction. Sintering was found to be predominant for highly porous <span class="hlt">oxides</span> and less of an influence on the denser ores. It was found using an indirect measurement technique that the rate constants for wustite reduction were higher for the porous <span class="hlt">iron-oxide</span> than dense hematite ore at higher temperatures (> 1423 K). Such an indirect mode of measurement was used to minimize the influence of sintering of the porous <span class="hlt">oxide</span> at these temperatures.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26507477','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26507477"><span id="translatedtitle">Nitrous <span class="hlt">Oxide</span>-dependent <span class="hlt">Iron</span>-catalyzed Coupling Reactions of Grignard Reagents.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Döhlert, Peter; Weidauer, Maik; Enthaler, Stephan</p> <p>2015-01-01</p> <p>The formation of carbon-carbon bonds is one of the fundamental transformations in chemistry. In this regard the application of palladium-based catalysts has been extensively investigated during recent years, but nowadays research focuses on <span class="hlt">iron</span> catalysis, due to sustainability, costs and toxicity issues; hence numerous examples for <span class="hlt">iron</span>-catalyzed cross-coupling reactions have been established, based on the coupling of electrophiles (R(1)-X, X = halide) with nucleophiles (R(2)-MgX). Only a small number of protocols deals with the <span class="hlt">iron</span>-catalyzed <span class="hlt">oxidative</span> coupling of nucleophiles (R(1)-MgX + R(2)-MgX) with the aid of <span class="hlt">oxidants</span> (1,2-dihaloethanes). However, some issues arise with these <span class="hlt">oxidants</span>; hence more recently the potential of the industrial waste product nitrous <span class="hlt">oxide</span> (N(2)O) was investigated, because the unproblematic side product N(2) is formed. Based on that, we demonstrate the catalytic potential of easily accessible <span class="hlt">iron</span> complexes in the <span class="hlt">oxidative</span> coupling of Grignard reagents. Importantly, nitrous <span class="hlt">oxide</span> was essential to obtain yields up to >99% at mild conditions (e.g. 1 atm, ambient temperature) and low catalyst loadings (0.1 mol%) Excellent catalyst performance is realized with turnover numbers of up to 1000 and turnover frequencies of up to 12000 h(-1). Moreover, a good functional group tolerance is observed (e.g. amide, ester, nitrile, alkene, alkyne). Afterwards the reaction of different Grignard reagents revealed interesting results with respect to the selectivity of cross-coupling product formation. PMID:26507477</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27668803','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27668803"><span id="translatedtitle">Defective <span class="hlt">iron-oxide</span> nanoparticles synthesised by high temperature plasma processing: a magnetic characterisation versus temperature.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Balasubramanian, C; Joseph, B; Orpe, P B; Saini, N L; Mukherjee, S; Dziedzic-Kocurek, K; Stanek, J; Di Gioacchino, D; Marcelli, A</p> <p>2016-11-01</p> <p>Magnetic properties and phase compositions of <span class="hlt">iron-oxide</span> nanoparticles synthesised by a high temperature arc plasma route have been investigated by Mössbauer spectroscopy and high harmonic magnetic AC susceptibility measurements, and correlated with morphological and structural properties for different synthesis conditions. The Mössbauer spectra precisely determined the presence of different <span class="hlt">iron-oxide</span> fractions in the investigated nanoparticles, while the high harmonic magnetic susceptibility measurements revealed the occurrence of metastable magnetic phases evolving in temperature and time. This study illustrates magnetic properties and dynamics of the magnetic configurations of <span class="hlt">iron-oxide</span> nanoparticles grown by high temperature plasma, a process less explored so far but extremely useful for synthesising large numbers of nanoparticles for industrial applications. PMID:27668803</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27668803','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27668803"><span id="translatedtitle">Defective <span class="hlt">iron-oxide</span> nanoparticles synthesised by high temperature plasma processing: a magnetic characterisation versus temperature.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Balasubramanian, C; Joseph, B; Orpe, P B; Saini, N L; Mukherjee, S; Dziedzic-Kocurek, K; Stanek, J; Di Gioacchino, D; Marcelli, A</p> <p>2016-11-01</p> <p>Magnetic properties and phase compositions of <span class="hlt">iron-oxide</span> nanoparticles synthesised by a high temperature arc plasma route have been investigated by Mössbauer spectroscopy and high harmonic magnetic AC susceptibility measurements, and correlated with morphological and structural properties for different synthesis conditions. The Mössbauer spectra precisely determined the presence of different <span class="hlt">iron-oxide</span> fractions in the investigated nanoparticles, while the high harmonic magnetic susceptibility measureme