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1

Reduction of aromatic nitrocompounds with hydrazine hydrate in the presence of an iron oxide hydroxide catalyst  

Microsoft Academic Search

The catalytic activities of several iron oxides and oxide hydroxides have been tested in the reduction of substituted nitroarenes using hydrazine hydrate as reducing agent. An iron oxide catalyst, prepared by rapid precipitation of iron hydroxides from solutions of iron(III)chloride, showed the highest activity mainly due to its large BET surface area compared to other iron oxides. Mössbauer spectroscopy and

M Benz; A. M van der Kraan; R Prins

1998-01-01

2

Hydrated Iron Sulfate Minerals by FT-IR, ESEM and XRD: Effects of Hydration, Metal Ions, and Oxidative State  

NASA Astrophysics Data System (ADS)

Data from the Mars Exploration Rovers (MER) and orbital remote sensing have determined that iron-bearing sulfates and iron-sulfates account for much of the mineralogical variation on Martian chemical sediments. We have begun a comprehensive study to evaluate a suite of hydrated iron sulfate minerals at different levels of oxidation or mineral phases using micro-FT-IR, ESEM and XRD. Selected minerals include jarosite, copiapite, coquimbite, halotrichite, kornelite, melanterite, rhomboclase, roemerite, rozenite, and szomolnokite. The structure and wavelength of the water bands are controlled by the immediate proximity of the water molecules to the Fe3+ and Fe2+ cores. Iron and aluminum change the fundamental vibration amplitudes and shift the energy requirement for a specific bond vibration. The original mineral spectral signature can be present even after oxidative products form on the iron sulfate surfaces and basic spectral lines can be analyzed. When mineral samples were sectioned and analysis performed on the interior mineral surfaces, the spectra showed the predominant spectral lines under both conditions with most variations occurring in peak definition. ESEM-EDAX and XRD analysis confirmed the presence of oxidative products on the mineral surfaces even when the mineral samples were stored in anoxic conditions (under mineral oil) and refrigerated in airtight containers after sampling. Spectral variability between 30 micron spots within 200x200 micron areas showed minimal compositional / spectral variability. The micro-spectroscopic approach permits the study of complex iron sulfate mineral structures (e.g. evaporite sequences, crystal formations) to determine the hydration, metal ion, and oxidative state in terrestrial analog systems and on future Mars missions, without destruction of the sample.

Mielke, R.; Blaney, D.; Nordstrom, K.; Aplers, C.; Coleman, M.

2007-12-01

3

Kinetics of the reduction of aromatic nitro compounds with hydrazine hydrate in the presence of an iron oxide hydroxide catalyst  

Microsoft Academic Search

A kinetic model has been developed for the reduction of 4-nitrotoluene to 4-toluidine and 4-nitroaniline to p-phenylenediamine by hydrazine hydrate in the presence of an iron oxide hydrogen-transfer catalyst. While the initial concentrations of 4-nitrotoluene, 4-nitroaniline and hydrazine hydrate were varied the conversion was measured with gas chromatography and UV\\/Vis spectroscopy. The rate constants and adsorption constants of 4-nitrotoluene, 4-nitroaniline

M. Benz; R. Prins

1999-01-01

4

Cesium adsorption in hydrated iron oxide particles suspensions: an NMR study.  

PubMed

137Cs is an important component of nuclear waste which may pollute water. Its migration in natural environments is slowed down by adsorption on minerals. Cesium adsorption on akaganeite (beta-FeOOH) particles, dextran-coated ferrihydrite (5 Fe(2)O(3)-9H(2)O) particles, and ferritin in aqueous solutions is studied with (133)Cs nuclear magnetic resonance measurements. The longitudinal relaxation time (T(1)) of (133)Cs in the presence of such magnetic particles depends on whether the ions bind to the particle or not. T(1) of (133)Cs ions in aqueous solutions containing the same amount of magnetized particles will not depend on cesium concentration if relaxation is governed by diffusion (when cesium is not able to bind), but it will depend on cesium concentration if exchange governs relaxation (when cesium is able to bind). The method is successfully tested using TEMPO, a nitroxide stable free radical whose relaxation is due to diffusion. (133)Cs relaxation in solutions of ferritin, akaganeite, and dextran-coated ferrihydrite particles is found to result from a cationic exchange of cesium ions between particles surface and bulk ions, owing to adsorption. The effect of pH on (133)Cs relaxation in solutions of the particles is consistent with the adsorption properties of cations on hydrated iron oxides. PMID:12202142

Gossuin, Yves; Colet, Jean-Marie; Roch, Alain; Muller, Robert N; Gillis, Pierre

2002-07-01

5

Reduction of aromatic nitro compounds with hydrazine hydrate in the presence of an iron oxide hydroxide catalyst. I. The reduction of monosubstituted nitrobenzenes with hydrazine hydrate in the presence of ferrihydrite  

Microsoft Academic Search

A great variety of monosubstituted nitrobenzene derivatives has been reduced in good yield to the corresponding anilines with hydrazine hydrate in the presence of an iron oxide hydroxide catalyst prepared by precipitation from an aqueous iron(III) solution with sodium hydroxide. The dependence of the rate of reduction on the nature and the position of additional substituents other than the nitro

Max Lauwiner; Paul Rys; Jörg Wissmann

1998-01-01

6

Reduction of aromatic nitro compounds with hydrazine hydrate in the presence of an iron oxide\\/hydroxide catalyst. III. The selective reduction of nitro groups in aromatic azo compounds  

Microsoft Academic Search

The study on the range of applications of a cheap iron oxide\\/hydroxide modification as a H-transfer catalyst opened up a promising new route for the selective reduction of nitro groups in aromatic azo compounds. A series of monosubstituted 3- and 4-nitrophenylazobenzenes were reduced selectively by hydrazine hydrate in the presence of the iron oxide\\/hydroxide catalyst. The selectivity for the nitro

Max Lauwiner; Ronny Roth; Paul Rys

1999-01-01

7

Hydration of bilayered graphene oxide.  

PubMed

The hydration of graphene oxide (GO) membranes is the key to understand their remarkable selectivity in permeation of water molecules and humidity-dependent gas separation. We investigated the hydration of single GO layers as a function of humidity using scanning force microscopy, and we determined the single interlayer distance from the step height of a single GO layer on top of one or two GO layers. This interlayer distance grows gradually by approximately 1 Å upon a relative humidity (RH) increase in the range of 2 to ?80%, and the immersion into liquid water increases the interlayer distance further by another 3 Å. The gradual expansion of the single interlayer distance is in good agreement with the averaged distance measured by X-ray diffraction on multilayered graphite oxides, which is commonly explained with an interstratification model. However, our experimental design excludes effects connected to interstratification. Instead we determine directly if insertion of water into GO occurs strictly by monolayers or the thickness of GO layers changes gradually. We find that hydration with up to 80% RH is a continuous process of incorporation of water molecules into single GO layers, while liquid water inserts as monolayers. The similarity of hydration for our bilayer and previously reported multilayered materials implies GO few and even bilayers to be suitable for selective water transport. PMID:24922580

Rezania, B; Severin, Nikolai; Talyzin, Alexandr V; Rabe, Jürgen P

2014-07-01

8

Kinetics of thermal decomposition of intermediate hydrates and basic salts of iron(II) sulphate heptahydrate  

Microsoft Academic Search

The kinetics of thermal decomposition of iron(II) sulphate hexa- to monohydrates, as well as the hydroxy- and oxysulphates of iron(III), are presented and discussed. The results confirm that the final intermediate that decomposes to iron(III) oxide and sulphur trioxide during the thermal decomposition of any hydrate of iron(II) sulphate is the oxysulphate, Fe2O(SO4)2.

T. P. Prasad

1986-01-01

9

Leaching of oxidic zinc materials with chlorine and chlorine hydrate  

NASA Astrophysics Data System (ADS)

Low grade zinc ores and residues were leached in chlorine water and chlorine hydrate water mixtures. It was found that the rate of leaching Adrar ore and Electric Arc Furnace dust obeyed a shrinking core diffusion model, whereas, the rate of leaching of Turkish ore appeared to be controlled by a surface reaction. In all cases, lead leached with the zinc but the iron oxides remained virtually undissolved.

Thomas, B. K.; Fray, D. J.

1981-06-01

10

Initial Oxidation of Iron and Iron Nitride.  

National Technical Information Service (NTIS)

Iron nitride layers on low alloyed steels are of interest because they improve their performance with respect to wear, fatigue and corrosion. Subjecting a nitrided workpiece to an oxidation treatment brings about an iron-oxide layer at the surface, which ...

P. Graat

1998-01-01

11

Iron oxide pillared graphite.  

PubMed

We show that alpha-Fe2O3- and Fe3O4-pillared graphites can be prepared by pillaring graphite oxide with trinuclear iron acetato complex ion and calcining it in air and in vacuo, respectively. A pillared graphite structure is confirmed by transmission electron microscopy observations. The adsorption isotherms of water indicate that the mesopores of Fe3O4-pillared graphite constitute a hydrophobic nanospace. PMID:15982031

Morishige, Kunimitsu; Hamada, Takanobu

2005-07-01

12

Evolution of iron speciation during hydration of C4AF.  

PubMed

It is now well accepted and demonstrated that calcium silicate, calcium aluminate and calcium sulfo aluminate (ettringite, AFm) phases exhibit a good capability to fix metals and metalloids. Unfortunately the role of minor phases and especially calcium-ferric aluminate phase, shorthand C4AF is not well defined. In other systems like in soils or sediments iron phases play a key role in the fixation of pollutant. In cement sorption isotherms, indicated that various metals can be retained by the C4AF hydrated products. Therefore the capabilities of those phase to retain heavy metal should not be neglected. Previous investigations have shown that the minerals formed during the hydration of C4AF are similar to those formed from C3A (pure tri-calcium aluminate) under comparable conditions. Nevertheless no investigation was conducted at the molecular level and there is still a controversy whether Fe substitutes for Al in the hydrated minerals in whole or in part, or if it forms FeOOH clusters scattered throughout the matrix. In this context we have conducted XAS experiments using synchrotron radiation. It was found that the hydration of C4AF forms C3AH6 (hydrogarnet) in which Fe randomly substitutes for Al as well as an amorphous FeOOH phase. Intermediate products like AFm (i.e., an ill organized lamellar phase) are also formed but rapidly evolve to C3AH6; iron does not seem to be incorporated in the AFm structure. PMID:16697177

Rose, J; Bénard, A; El Mrabet, S; Masion, A; Moulin, I; Briois, V; Olivi, L; Bottero, J-Y

2006-01-01

13

Competitive Oxidation and Hydration During Aqueous Alteration of Asteroids  

NASA Technical Reports Server (NTRS)

Introduction: Studies of chondrites show that incorporation of H2O ice during formation of asteroids followed by radioactive heating caused partial oxidation and hydration of primary reduced and anhydrous rocks. Oxidation of kamacite, phosphides, troilite and organic polymers occurred through consumption of water s oxygen and release of H2. Hydration caused formation of serpentine, saponite, chlorite, talc and hydrated salts. Since H2O was the major reactant in oxidation and hydration, these processes could have been competitive. Redox reactions in asteroids should have been closely connected to hydration (dehydration) during aqueous alteration and thermal metamorphism. For example, dehydration and reduction release H2O that can be consumed in oxidation and hydration, respectively. We model asteroidal processes in order to quantify the fate of H2O and water s oxygen in major redox and hydration/dehydration reactions. Model: Equilibrium compositions in the gas-solid-liquid

Zolotov, M. Y.; Mironenko, M. V.; Shock, E. L.

2005-01-01

14

Enzymes of respiratory iron oxidation  

SciTech Connect

This report describes experimental progress in characterizing and identifying redox proteins in a number of iron-oxidizing bacteria. Sections of the paper are entitled (1) In Situ electrolysis was explored to achieve enhanced yields of iron-oxidizing bacteria, (2)Structure/function studies were performed on redox-active biomolecules from Thiobacillus ferrooxidans, (3) Novel redox-active biomolecules were demonstrated in other iron autotrophs, and (4) New probes of metalloprotein electron-transfer reactions were synthesized and characterized.

Blake, R. II.

1992-01-01

15

Formation of silica iron oxide glasses  

NASA Astrophysics Data System (ADS)

The microemulsion-gel method was developed as an alternative process in the production of room temperature glasses. This method is based on the formation of a microemulsion, to which is added a metal alkoxide that undergoes hydrolysis and condensation to form an oxide network, which is dried into glass. The goal of this work is to understand the sol-gel process upon addition of hydrate metal salts. The thermal transitions of the silica containing ferric nitrate hydrate were examined by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). Using infrared (IR) spectroscopy and X-ray diffraction (XRD). The glasses with a less than 30 mol % iron nitrate were amorphous, while those higher concentration were crystalline. Based on XRD the thermal transitions did not alter the crystallinity. The IR spectra indicated the existence of Si-O-Fe bonds. Thermal analysis indicated similar transitions as exhibited by pure iron nitrate with minor modifications due to interactions with the silica. The reaction between tetraethoxysilane and chloral hydrate in ethanol was followed by NMR of the sp{29}Si nucleus at two different pHs. The sp{29}Si NMR spectra were similar to those reported for the reactions in alcohol between tetraethoxysilane and water of low pH, and for the reactions in the presence of inorganic hydrate. At pH 4, monomene silicon species were detected where at pH 2 the reaction was sufficiently rapid that multi hydroxy monomers were not detected as expected from the catalysts. The reaction proceeded without adding water. The reaction between aluminum chloride and methoxydimethyloctylsilane was investigated at room temperature using NMR and IR spectroscopy in addition to a molecular weight determination from the freezing point reduction in benzene. The structure as deduced from the experimental results was found to be a dimer containing two silicon atoms and two aluminum atoms of which the latter were tetrahedrally coordinated.

Al-Bawab, Abeer F.

16

Electrochemical behavior of hydrated molybdenum oxides in rechargeable lithium batteries  

Microsoft Academic Search

Oxide-hydrates of molybdenum (OHM) are investigated as 3-volt cathode materials for rechargeable lithium batteries. These\\u000a materials with different water content showed a much better performance than that of MoO3 as cathode of the rechargeable lithium battery. We report the electrochemical characteristics of Li\\/\\/OHM batteries using\\u000a the oxides and oxide-hydrates of molybdenum which were synthesized from molybdic acid. The oxide has

B. Yebka; C. Julien; G. A. Nazri

1999-01-01

17

21 CFR 186.1374 - Iron oxides.  

Code of Federal Regulations, 2013 CFR

(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 (III) oxide (CAS Reg. No. 1309-37-1, red-brown to black trigonal crystals). (b) In accordance with §...

2013-04-01

18

Methane-to-methanol oxidation by the hydrated iron(IV) oxo species in aqueous solution: a combined DFT and car-parrinello molecular dynamics study.  

PubMed

Previously, we have shown that the ferryl ion ([FeIVO]2+) is easily produced from Fenton's reagent (i.e., a mixture of Fe2+ ions and H2O2 in aqueous solution), using DFT and Car-Parrinello MD calculations. To verify that the ferryl ion can indeed act as the active species in oxidation reactions with Fenton's reagent, we study in the present paper the reactivity of the ferryl ion toward an organic substrate, in particular the oxidation of methane to methanol. In the first part of this paper, we perform static DFT calculations on the reaction of CH4 with the [(H2O)5FeIVO]2+ complex in vacuo that show a strong prevalence of the oxygen-rebound mechanism over the methane coordination mechanism. This is in agreement with the static DFT results for methane oxidation by biocatalysts MMO and P450, but not with those for methane oxidation by bare metal-oxo ions, where the methane coordination mechanism prevails. The highest energy barrier in the oxygen-rebound mechanism is only 3 kcal/mol in vacuo, whereas in the methane coordination mechanism the highest barrier is 23 kcal/mol. Overall the oxidation reaction energy is downhill by 47 kcal/mol. We conclude that the ferryl ion can indeed act as the oxidative intermediate in the Fenton oxidation of organic species. In the second part of this paper, we perform a preliminary assessment of solvent effects on the oxidation by the ferryl ion in aqueous solution using the method of constrained (first principles) molecular dynamics. The free energy barrier of the H-abstraction reaction from methane by the ferryl ion (i.e., the first step in the rebound mechanism) in aqueous solution is, with 22 kcal/mol in solution, significantly higher than in vacuo. Given the fact that methane has a relatively strong C-H bond (ca. 10 kcal/mol stronger than the C-H bonds in the more typical Fenton's reagent substrates), we infer that for many organic substrates oxidation with the ferryl ion as an active intermediate may be a perfectly viable route. PMID:15053625

Ensing, Bernd; Buda, Francesco; Gribnau, Michiel C M; Baerends, Evert Jan

2004-04-01

19

Problem of the hydration resistance of calcium oxide  

SciTech Connect

A study was made of the hydration tendencies of lime of varying degrees of sinterability. Some ways are indicated of increasing the hydration resistance of CaO. The investigation used pure grade calcium oxide. The lime was calcined at 1300, 1750, and 1950/sup 0/C with a soak of 2 h. To change the hydration resistance of the lime the additives Y/sub 2/O/sub 3/, MnO/sub 2/, and Cr/sub 2/O/sub 3/ were incorporated in the composition. Specimens prepared from lime with additions of yttrium oxide formed solid solutions on the basis of CaO during firing at 1950/sup 0/C. This contributed to an increase in the hydration resistance. Specimens prepared from CaO with additions of manganese and chromium oxides, fired at 1750/sup 0/C, also had a high hydration resistance.

Pitak, N.V.; Turchinova, L.N.; Gavrish, A.M.; Gul'ko, N.V.; Romanenko, S.N.

1988-09-01

20

Recovery of iron oxide from coal fly ash  

DOEpatents

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.

Dobbins, Michael S. (Ames, IA); Murtha, Marlyn J. (Ames, IA)

1983-05-31

21

Gaseous reduction of iron oxides: Part III. Reduction-oxidation of porous and dense iron oxides and iron  

Microsoft Academic Search

The internal reduction of high-grade granular hematite ore in hydrogen and carbon monoxide, and also the internal oxidation\\u000a of porous iron granules in CO2-CO mixtures have been investigated. To assist the interpretation of the rate data for porous iron and iron oxides, rate measurements\\u000a have been made also with dense wustite, previously grown on iron by oxidation. The iron formed

E. T. Turkdogan; J. V. Vinters

1972-01-01

22

Iron biomineralization by anaerobic neutrophilic iron-oxidizing bacteria  

Microsoft Academic Search

Minerals formed by bio-oxidation of ferrous iron (Fe(II)) at neutral pH, their association with bacterial ultrastructures as well as their impact on the metabolism of iron-oxidizing bacteria remain poorly understood. Here, we investigated iron biomineralization by the anaerobic nitrate-dependent iron-oxidizing bacterium Acidovorax sp. strain BoFeN1 in the presence of dissolved Fe(II) using electron microscopy and Scanning Transmission X-ray Microscopy (STXM).

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

2009-01-01

23

EPR Spectra of Modified Iron Oxides  

Microsoft Academic Search

EPR spectra of iron oxides, obtained by calcination of iron oxide-hydroxides a-, ß-, ?- and d-FeOOH, and ruthenium catalysts based on them (Ru\\/Fe2O3 and Ru\\/Na-Fe2O3), used for the water-gas shift reaction (WGSR), were analyzed. The iron oxide (B) (obtained from ß-FeOOH) is inactive in WGSR. Deposition of ruthenium on iron oxide supports, in particular on those modified with sodium, enhanced

Anna Basi?ska; Wanda Wójtowicz; Andrzej B. Wi?ckowski; Florian Domka

2000-01-01

24

Synthesis of iron oxide nanoworms  

NASA Astrophysics Data System (ADS)

We report on the synthesis of highly crystalline iron oxide nanoworms via a modified ``heat-up'' method using iron oleate as the precursor. According to a detailed nanoparticle growth study, we proposed that the nanoworms resulted from the aggregation of spherical iron oxide nanoparticles. The aggregation was induced by the high percentage coverage of a weakly bound ligand (trioctylphosphine oxide) on the iron oxide surfaces. A time dependent study clearly demonstrated the evolution of these nanostructures from spheres to one-dimensional nanoworms. The diameter of the nanoworms was similar to the spherical nanoparticles observed at an early stage of the reaction, and the length of the nanoworms changed from 50-200 nm during the reaction. The spheres and the nanoworms were both maghemite crystal structures, but the magnetic properties changed from superparamagnetic for the spheres to ferromagnetic for the elongated nanoworms. These one dimensional structures will offer additional opportunities for biomedical applications because of their high blood circulation time and large surface area for bio-labeling.

Palchoudhury, Soubantika; Xu, Yaolin; Goodwin, Johnny; Bao, Yuping

2011-04-01

25

Oxidation sizing of iron and iron-neodymium-boron powders  

Microsoft Academic Search

A powder sizing test developed for use on WC powders has been extended for use on iron and iron-neodymium-boron powders. In this test the particle size is derived from the rate of oxidation, because finer powders oxidize quicker. The rate of oxidation is monitored in a thermogravimetric analyser, where the powders are subjected to a controlled heating rate from room

M. Stewart; B. Roebuck; M. G. Gee

1991-01-01

26

Extracellular Iron Biomineralization by Photoautotrophic Iron-Oxidizing Bacteria  

Microsoft Academic Search

Iron oxidation at neutral pH by the phototrophic anaerobic iron-oxidizing bacterium Rhodobacter sp. strain SW2 leads to the formation of iron-rich minerals. These minerals consist mainly of nano-goethite (-FeOOH), which precipitates exclusively outside cells, mostly on polymer fibers emerging from the cells. Scanning transmission X-ray microscopy analyses performed at the C K-edge suggest that these fibers are composed of a

Jennyfer Miot; Karim Benzerara; Martin Obst; Andreas Kappler; Florian Hegler; Sebastian Schadler; Camille Bouchez; Francois Guyot; Guillaume Morin

2009-01-01

27

Description and classification of uranium oxide hydrate sheet anion topologies  

Microsoft Academic Search

The sheets of uranyl ions (U{sup 6+}O){sup 2+} in the structures of all uranyl oxide hydrates (UOH) (and the structurally related - and forms of UO) are based on only four structural unit chains. Each sheet type may be reduced to its underlying sheet anion topology to determine the chains present within each topology and to describe the structural relationships

M. L. Miller; R. J. Finch; P. C. Burns; R. C. Ewing

1996-01-01

28

Hydration behavior and dynamics of water molecules in graphite oxide  

Microsoft Academic Search

In contrast to graphite intercalation compounds, graphite oxide (GO) is hydrophilic. However, the information about the mobility of the water molecules is still sparse. We show in this report that the degree of hydration and the kinetics of water uptake depend crucially on the preparation and aging conditions. The best sample we have ever got shows layer distances of 8,

A. Lerf; A. Buchsteiner; J. Pieper; S. Schöttl; I. Dekany; T. Szabo; H. P. Boehm

2006-01-01

29

Exploring Microbial Iron Oxidation in Wetland Soils  

Microsoft Academic Search

Iron is one of the most abundant elements on earth and is essential for life. Because of its importance, iron cycling and its interaction with other chemical and microbial processes has been the focus of many studies. Iron-oxidizing bacteria (FeOB) have been detected in a wide variety of environments. Among those is the rhizosphere of wetland plants roots which release

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

2009-01-01

30

21 CFR 73.200 - Synthetic iron oxide.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 2009-04-01 false Synthetic iron oxide. 73.200 Section 73...CERTIFICATION Foods § 73.200 Synthetic iron oxide. (a) Identity. (1) The color additive synthetic iron oxide consists of any one...

2009-04-01

31

21 CFR 73.200 - Synthetic iron oxide.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Synthetic iron oxide. 73.200 Section 73...CERTIFICATION Foods § 73.200 Synthetic iron oxide. (a) Identity. (1) The color additive synthetic iron oxide consists of any one...

2010-04-01

32

Iron biomineralization by anaerobic neutrophilic iron-oxidizing bacteria  

NASA Astrophysics Data System (ADS)

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 offer potential signatures of those metabolisms that can be looked for in the geological record.

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

33

Magnetic characterization of bulk nanostructured iron oxides  

Microsoft Academic Search

Iron oxide nanopowders were consolidated using a current activated method at varying temperatures. The resulting bulk dense samples with crystal sizes in the nanometric range were found to be mixtures of cubic and hexagonal phases of iron oxides (nanocomposites). Magnetic characterization reveals one abrupt increase, up to 300%, in the magnetization with increasing temperature. The coercivity Hc steps down 300%

J. R. Morales; J. E. Garay; M. Biasini; W. P. Beyermann

2008-01-01

34

Tannin biosynthesis of iron oxide nanoparticles  

NASA Astrophysics Data System (ADS)

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.

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

2010-08-01

35

Photooxidation of hydrated Fe2+-significance for banded iron formations  

Microsoft Academic Search

The Precambrian banded iron formations (BIFs) are the major iron ore sources on the Earth. They consist of extensive iron-rich and iron-poor layers within siliceous sedimentary rocks1,2. The banding has been attributed to variations in the conditions for precipitation of Fe2+ in ancient seas. The most favoured precipitating agent is oxygen3-8 this would lead in the first place to insoluble

Paul S. Braterman; A. Graham Cairns-Smith; Robert W. Sloper

1983-01-01

36

Nanosized Iron Oxide Colloids Strongly Enhance Microbial Iron Reduction? †  

PubMed Central

Microbial iron reduction is considered to be a significant subsurface process. The rate-limiting bioavailability of the insoluble iron oxyhydroxides, however, is a topic for debate. Surface area and mineral structure are recognized as crucial parameters for microbial reduction rates of bulk, macroaggregate iron minerals. However, a significant fraction of iron oxide minerals in the subsurface is supposed to be present as nanosized colloids. We therefore studied the role of colloidal iron oxides in microbial iron reduction. In batch growth experiments with Geobacter sulfurreducens, colloids of ferrihydrite (hydrodynamic diameter, 336 nm), hematite (123 nm), goethite (157 nm), and akaganeite (64 nm) were added as electron acceptors. The colloidal iron oxides were reduced up to 2 orders of magnitude more rapidly (up to 1,255 pmol h?1 cell?1) than bulk macroaggregates of the same iron phases (6 to 70 pmol h?1 cell?1). The increased reactivity was not only due to the large surface areas of the colloidal aggregates but also was due to a higher reactivity per unit surface. We hypothesize that this can be attributed to the high bioavailability of the nanosized aggregates and their colloidal suspension. Furthermore, a strong enhancement of reduction rates of bulk ferrihydrite was observed when nanosized ferrihydrite aggregates were added.

Bosch, Julian; Heister, Katja; Hofmann, Thilo; Meckenstock, Rainer U.

2010-01-01

37

Nanosized iron oxide colloids strongly enhance microbial iron reduction.  

PubMed

Microbial iron reduction is considered to be a significant subsurface process. The rate-limiting bioavailability of the insoluble iron oxyhydroxides, however, is a topic for debate. Surface area and mineral structure are recognized as crucial parameters for microbial reduction rates of bulk, macroaggregate iron minerals. However, a significant fraction of iron oxide minerals in the subsurface is supposed to be present as nanosized colloids. We therefore studied the role of colloidal iron oxides in microbial iron reduction. In batch growth experiments with Geobacter sulfurreducens, colloids of ferrihydrite (hydrodynamic diameter, 336 nm), hematite (123 nm), goethite (157 nm), and akaganeite (64 nm) were added as electron acceptors. The colloidal iron oxides were reduced up to 2 orders of magnitude more rapidly (up to 1,255 pmol h(-1) cell(-1)) than bulk macroaggregates of the same iron phases (6 to 70 pmol h(-1) cell(-1)). The increased reactivity was not only due to the large surface areas of the colloidal aggregates but also was due to a higher reactivity per unit surface. We hypothesize that this can be attributed to the high bioavailability of the nanosized aggregates and their colloidal suspension. Furthermore, a strong enhancement of reduction rates of bulk ferrihydrite was observed when nanosized ferrihydrite aggregates were added. PMID:19915036

Bosch, Julian; Heister, Katja; Hofmann, Thilo; Meckenstock, Rainer U

2010-01-01

38

Transition in the nanoporous structure of iron oxides during the oxidation of iron nanoparticles and nanowires  

Microsoft Academic Search

Changes in morphology during the oxidation of iron nanoparticles and nanowires in the temperature range 473–873K have been studied by transmission electron microscopy. Iron nanoparticles and wires become hollow nanoparticles and nanotubes of magnetite at temperatures below 673K as a result of vacancy aggregation during the oxidation process, resulting from the outward diffusion of iron ions through the magnetite layer.

Ryusuke Nakamura; Gen Matsubayashi; Hiroaki Tsuchiya; Shinji Fujimoto; Hideo Nakajima

2009-01-01

39

Platinum Attachments on Iron Oxide Nanoparticle Surfaces  

SciTech Connect

Platinum nanoparticles supported on metal oxide surfaces have shown great potential as heterogeneous catalysts to accelerate electrochemical processes, such as the oxygen reduction reaction in fuel cells. Recently, the use of magnetic supports has become a promising research topic for easy separation and recovery of catalysts using magnets, such as Pt nanoparticles supported on iron oxide nanoparticles. The attachment of Pt on iron oxide nanoparticles is limited by the wetting ability of the Pt (metal) on ceramic surfaces. A study of Pt nanoparticle attachment on iron oxide nanoparticle surfaces in an organic solvent is reported, which addresses the factors that promote or inhibit such attachment. It was discovered that the Pt attachment strongly depends on the capping molecules of the iron oxide seeds and the reaction temperature. For example, the attachment of Pt nanoparticles on oleic acid coated iron oxide nanoparticles was very challenging, because of the strong binding between the carboxylic groups and iron oxide surfaces. In contrast, when nanoparticles are coated with oleic acid/tri-n-octylphosphine oxide or oleic acid/oleylamine, a significant increase in Pt attachment was observed. Electronic structure calculations were then applied to estimate the binding energies between the capping molecules and iron ions, and the modeling results strongly support the experimental observations.

Palchoudhury, Soubantika; Xu, Yaolin; An, Wei; Turner, C. H.; Bao, Yuping

2010-04-30

40

Temperature dependence of graphene oxide reduced by hydrazine hydrate  

NASA Astrophysics Data System (ADS)

Graphene oxide (GO) was successfully prepared by a modified Hummer's method. The reduction effect and mechanism of the as-prepared GO reduced with hydrazine hydrate at different temperatures and time were characterized by x-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), elemental analysis (EA), x-ray diffractions (XRD), Raman spectroscopy and thermo-gravimetric analysis (TGA). The results showed that the reduction effect of GO mainly depended on treatment temperature instead of treatment time. Desirable reduction of GO can only be obtained at high treatment temperature. Reduced at 95 °C for 3 h, the C/O atomic ratio of GO increased from 3.1 to 15.1, which was impossible to obtain at low temperatures, such as 80, 60 or 15 °C, even for longer reduction time. XPS, 13C NMR and FTIR results show that most of the epoxide groups bonded to graphite during the oxidation were removed from GO and form the sp2 structure after being reduced by hydrazine hydrate at high temperature (>60 °C), leading to the electric conductivity of GO increasing from 1.5 × 10 - 6 to 5 S cm - 1, while the hydroxyls on the surface of GO were not removed by hydrazine hydrate even at high temperature. Additionally, the FTIR, XRD and Raman spectrum indicate that the GO reduced by hydrazine hydrate can not be entirely restored to the pristine graphite structures. XPS and FTIR data also suggest that carbonyl and carboxyl groups can be reduced by hydrazine hydrate and possibly form hydrazone, but not a C = C structure.

Ren, Peng-Gang; Yan, Ding-Xiang; Ji, Xu; Chen, Tao; Li, Zhong-Ming

2011-02-01

41

Extracellular Iron Biomineralization by Photoautotrophic Iron-Oxidizing Bacteria ? †  

PubMed Central

Iron oxidation at neutral pH by the phototrophic anaerobic iron-oxidizing bacterium Rhodobacter sp. strain SW2 leads to the formation of iron-rich minerals. These minerals consist mainly of nano-goethite (?-FeOOH), which precipitates exclusively outside cells, mostly on polymer fibers emerging from the cells. Scanning transmission X-ray microscopy analyses performed at the C K-edge suggest that these fibers are composed of a mixture of lipids and polysaccharides or of lipopolysaccharides. The iron and the organic carbon contents of these fibers are linearly correlated at the 25-nm scale, which in addition to their texture suggests that these fibers act as a template for mineral precipitation, followed by limited crystal growth. Moreover, we evidence a gradient of the iron oxidation state along the mineralized fibers at the submicrometer scale. Fe minerals on these fibers contain a higher proportion of Fe(III) at cell contact, and the proportion of Fe(II) increases at a distance from the cells. All together, these results demonstrate the primordial role of organic polymers in iron biomineralization and provide first evidence for the existence of a redox gradient around these nonencrusting, Fe-oxidizing bacteria.

Miot, Jennyfer; Benzerara, Karim; Obst, Martin; Kappler, Andreas; Hegler, Florian; Schadler, Sebastian; Bouchez, Camille; Guyot, Francois; Morin, Guillaume

2009-01-01

42

Gold supported iron oxide–hydroxide derived from iron ore tailings for CO oxidation  

Microsoft Academic Search

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

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

2009-01-01

43

Biogeochemical Properties of Bacteriogenic Iron Oxides  

Microsoft Academic Search

Bacteriogenic iron oxides (BIOS) are composite materials that consist of intact and partly degraded remains of bacterial cells intermixed with variable amounts of poorly ordered hydrous ferric oxide (HFO) minerals. They form in response to chemical or bacterial oxidation of Fe, which gives rise to Fe. Once formed, Fe tends to undergo hydrolysis to precipitate in association with bacterial cells.

F. G. Ferris

2005-01-01

44

Spectroscopic and electrochemical studies of electrochromic hydrated nickel oxide films  

SciTech Connect

The electrochromic properties of hydrated nickel oxide thin films electrochemically deposited by anodization onto doped tin oxide-coated glass have been studied by transmittance measurements, cyclic voltammetry, Fourier-transform infrared spectroscopy, and ion-backscattering spectrometry. The spectral transmittance is reported for films switched in both the bleached and colored states. The photopic transmittance (T/sub p/) can be switched from T/sub p/(bleached) = 0.77 to T/sub p/(colored) = 0.21, and the solar transmittance (T/sub S/) can be switched from T/sub S/(bleached) = 0.73 to T/sub S/(colored = 0.35. Also reported is the near-infrared transmittance (T/sub NIR/), which was found to switch from T/sub NIR/(bleached) = 0.72 to T/sub NIR/(colored) = 0.55 for a film thickness of 500 A. The bleached condition is noted to have very low solar absorption in both the visible and solar regions. Ion-backscattering spectrometry was performed on the hydrated nickel oxide film, yielding a composition of NiO/sub 1.0/ (dehydrated). Cyclic voltammetry showed that, for films in the bleached or colored state, the reversible reaction is Ni(OH)/sub 2/ ..-->.. NiOOH + H/sup +/ + e/sup -/. Voltammetry also showed that the switching of the film is controlled by the diffusion of protons, where OH/sup -/ plays a role in the reaction mechanism. Analysis of the hydrated nickel-oxide thin films by Fourier-transform infrared spectroscopy revealed that both the bleached and colored states contain lattice water and hydroxyl groups. The surface hydroxyl groups play an important role in the coloration and bleaching of the anodically deposited nickel oxide thin films.

Yu, P.C.; Nazri, G.; Lampert, C.M.

1986-07-01

45

Microorganisms pumping iron: anaerobic microbial iron oxidation and reduction  

Microsoft Academic Search

Iron (Fe) has long been a recognized physiological requirement for life, yet for many microorganisms that persist in water, soils and sediments, its role extends well beyond that of a nutritional necessity. Fe(II) can function as an electron source for iron-oxidizing microorganisms under both oxic and anoxic conditions and Fe(III) can function as a terminal electron acceptor under anoxic conditions

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

2006-01-01

46

Oxidative electrochemistry of iron-selenocarbonyl porphyrins  

SciTech Connect

The oxidation of selenocarbonyl(5,10,15,20-tetraphenylporphinato)iron(II), (TPP)FeCSe, was studied in 1,2-dichloroethane solution at a Pt-button electrode. Results from detailed voltammetric and spectroelectrochemical experiments (both electronic and infrared) indicated that (TPP)FeCSe can be oxidized in two chemically reversible, one-electron transfers. This is comparable to thiocarbonyl iron porphyrin but is in marked contrast with the analogous carbonyl iron(II) porphyrin derivative. The latter complex loses CO concomitantly with the removal of the first electron. The product of the first oxidation of (TPP)FeCSe is a selenocarbonyl iron(III) porphyrin whereas the second oxidation step occurs at the periphery of the porphyrin ring, producing the selenocarbonyl iron (III) porphyrin cation radical. Addition of nitrogenous bases to solution generated the monoadduct, (TPP)FeCSe (nitrogenous base). This adduct was also oxidized in two discrete, one-electron transfers. The product of the first oxidation, ((TPP)Fe/sup III/CSe(nitrogenous base))/sup +/, was stable for hours. The product of the second oxidation, however, readily underwent nucleophilic attack by uncomplexed nitrogenous base present in solution. The electronic effects generated by the ligand trans to the selenocarbonyl moiety are discussed in the context of their influence on the spectral, electrochemical, and thermodynamic properties of the selenocarbonyl iron porphyrin.

Gorce, J.N.; Bottomley, L.A.

1985-05-08

47

Iron Oxide Superconcentrates by Caustic Leaching.  

National Technical Information Service (NTIS)

The removal of silica from commercial iron oxide concentrates by dissolution with sodium hydroxide was investigated as a means for producing supergrade concentrates. The effects of strength of solution, temperature and digestion time on the extraction of ...

A. F. Colombo R. E. Green

1973-01-01

48

Nanoparticle iron–titanium oxide aerogels  

Microsoft Academic Search

Nanostructured iron oxide–titania aerogel materials have been prepared by sol–gel polymerization of iron acetylacetonate with titanium butoxide and supercritical drying. Their structural properties, including particle morphology, crystalline phase, bond linkage and surface area, were varied by addition of ferric oxide into the titania matrix, as characterized by means of HRTEM, XRD, FT-IR and the BET method. X-ray photoelectron spectra (XPS)

Chien-Tsung Wang; Shih-Hung Ro

2007-01-01

49

Synthesis and characterization of nanostructure hydrous iron–titanium binary mixed oxide for arsenic sorption  

Microsoft Academic Search

Synthesis of nanostructure hydrous iron–titanium binary mixed oxide (NHITBMO) had been reported by a simple method, and characterized\\u000a by the X-ray diffraction (XRD), thermal analysis, transmission electron microscope (TEM), Föurier Transform Infrared (FTIR),\\u000a surface area, and zero surface charge pH (pHzpc). The synthetic oxide was hydrated and microcrystalline with 77.8 m2 g?1 BET surface area. The particle size (nm) calculated using XRD

Kaushik Gupta; Shyamal Saha; Uday Chand Ghosh

2008-01-01

50

Evolution of iron speciation during hydration of C 4AF  

Microsoft Academic Search

It is now well accepted and demonstrated that calcium silicate, calcium aluminate and calcium sulfo aluminate (ettringite, AFm) phases exhibit a good capability to fix metals and metalloids. Unfortunately the role of minor phases and especially calcium-ferric aluminate phase, shorthand C4AF is not well defined. In other systems like in soils or sediments iron phases play a key role in

J.. Rose; A. Bénard; S. El Mrabet; A. Masion; I. Moulin; V. Briois; L. Olivi; J.-Y. Bottero

2006-01-01

51

Biogeochemistry of Arsenic in Iron Oxide Systems  

Microsoft Academic Search

The bioavailability of arsenic (As) in aerobic systems is governed by its adsorption onto metal oxide - most frequently iron (Fe) oxide - solid phases. The focus of this study is on how naturally occurring soil constituents (i.e. humic substances, silica, and phosphate) enhance the bioavailability of arsenate (As(V) oxyanion) and what effect enhanced As bioavailability has on food crops.

Paul R. Grossl; Matthew J. Eick; Markus Grafe

52

Removal of metallic iron on oxide slags  

SciTech Connect

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.

Shannon, G.N.; Fruehan, R.J.; Sridhar, S. [Carnegie Mellon University, Pittsburgh, PA (United States). Dept. of Material Science & Engineering

2009-10-15

53

Removal of Metallic Iron on Oxide Slags  

NASA Astrophysics Data System (ADS)

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 ({p_{O2}} of approximately 10-4 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 °C and in 160 seconds at 1600 °C.

Shannon, George N.; Fruehan, R. J.; Sridhar, Seetharaman

2009-10-01

54

Exploring Microbial Iron Oxidation in Wetland Soils  

NASA Astrophysics Data System (ADS)

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 ?- 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 sequences all represented novel culturable iron oxidizers most closely related to Gallionella spp. Based on their nucleotide sequences four groups could be identified, which were comparable to the DGGE banding pattern obtained before with the gradient tubes enrichments. The above mentioned nested PCR-DGGE method was used to study the distribution and community composition of Gallionella-like iron-oxidizing bacteria under the influence of plants species, soil depth, as well as season. Soil samples from Appels, Belgium, an intertidal, freshwater marsh known to hold intensive iron cycling, were taken from 5 different vegetation types in April, July and October 2007. Soil cores were sliced at 1-cm intervals and subjected to chemical and molecular analyses. The DGGE patterns showed that the community of iron-oxidizing bacteria differed with vegetation type, and sediment depth. Samples taken in autumn held lower diversity in Gallionella-related iron oxidizers than those sampled in spring and summer.

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

2009-04-01

55

A new refining process for iron oxide using iron ore and its application to hard ferrites  

NASA Astrophysics Data System (ADS)

Kawasaki Steel Corporation and Kawatetsu Mining Co., Ltd. have developed a new refining process to extract iron oxide from iron ore to meet the increase in demand for iron oxide for high- grade hard ferrites. This article discusses the quality of iron oxides and the characteristics of the hard ferrite magnets produced from them.

Nakashima, S.; Ikeda, Y.; Hirose, S.; Nakamura, H.; Ito, T.

1992-03-01

56

A new refining process for iron oxide using iron ore and its application to hard ferrites  

Microsoft Academic Search

Kawasaki Steel Corporation and Kawatetsu Mining Co., Ltd. have developed a new refining process to extract iron oxide from\\u000a iron ore to meet the increase in demand for iron oxide for high- grade hard ferrites. This article discusses the quality of\\u000a iron oxides and the characteristics of the hard ferrite magnets produced from them.

S. Nakashima; Y. Ikeda; S. Hirose; H. Nakamura; T. Ito

1992-01-01

57

IRON OXIDE NANOPARTICLE-INDUCED OXIDATIVE STRESS AND INFLAMMATION  

EPA Science Inventory

Nanoparticle Physicochemical Characterizations We first focused on creating NP systems that could be used to test our hypotheses and assessing their stability in aqueous media. The iron oxide NP systems were not stable in cell culture medium o...

58

The Low Temperature Oxidation of Iron  

Microsoft Academic Search

An electron diffraction study of the oxide films formed on abraded iron specimens by heating in air at temperatures ranging from 80° to 260°C has failed to detect structural effects due to a ``critical temperature'' in the neighborhood of 200°C. ?-Fe2O3 was found on specimens which were oxidized at any temperature above about 130°C provided the period of oxidation exceeded

H. R. Nelson

1938-01-01

59

Thermodynamics of Iron Oxidation in Metallurgical Slags  

NASA Astrophysics Data System (ADS)

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.

Matousek, Jan

2012-11-01

60

Thermodynamic constraints on microbial iron oxide reduction  

NASA Astrophysics Data System (ADS)

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.

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

2003-04-01

61

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

Microsoft Academic Search

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,

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

1992-01-01

62

The Exclusion of D2O from the Hydration Sphere of FeSO4 \\\\cdot 7H2O Oxidized by Thiobacillus ferrooxidans  

Microsoft Academic Search

Infrared spectra demonstrate that neither FeSO4 \\\\cdot 7H2O nor its bacterial or abiotic hydrated oxidation products incorporate deuterium in acid D2O solutions. Deuterium exchange occurred as bridging OD when bacterially oxidized iron was precipitated from D2O solutions as ferric hydroxysulfates. The exclusion of deuterium depended upon the stabilization of aquated Fe(II) and Fe(III) complexes by sulfate ions in outer-sphere coordination

Norman Lazaroff

1983-01-01

63

Direct synthesis of 1,4-diols from alkenes by iron-catalyzed aerobic hydration and C-H hydroxylation.  

PubMed

Various 1,4-diols are easily accessible from alkenes through iron-catalyzed aerobic hydration. The reaction system consists of a user-friendly iron phthalocyanine complex, sodium borohydride, and molecular oxygen. Furthermore, the effect of additional ligands on the iron complex was examined for a model reaction. The second hydroxy group is installed by direct C(sp(3))-H oxygenation, which is based on a [1,5]?hydrogen shift process of a transient alkoxy radical that is formed by formal hydration of the olefin. PMID:24488606

Hashimoto, Takuma; Hirose, Daisuke; Taniguchi, Tsuyoshi

2014-03-01

64

Low temperature synthesis of bilayer hydrated cesium cobalt oxide  

SciTech Connect

Bilayer hydrated Na{sub 0.35}CoO{sub 2}.1.3H{sub 2}O structure has re-directed superconductivity research in recent years. Here, we develop a low temperature synthesis method to prepare a novel hydrous Cs{sub 0.2}CoO{sub 2}.0.63H{sub 2}O compound in one step. The bilayer-hydrate of Cs{sub 0.2}CoO{sub 2}.0.63H{sub 2}O with a greatest interlayer spacing d=10.0(2) A among alkali cobalt oxides has been grown in crystal form. Magnetic susceptibility measurement of Cs{sub 0.2}CoO{sub 2}.0.63H{sub 2}O displays a paramagnetic behavior down to 1.9 K. With the assistance of low temperature molten CsOH solvent, crystals of Rb{sub 0.30}CoO{sub 2}.0.36H{sub 2}O and K{sub 0.35}CoO{sub 2}.0.4H{sub 2}O can be grown. The results provide the capability for preparing a novel hydrous structure and the systematic investigation of interlayer coupling effect of alkali ion insertion compounds. - Graphical abstract: BLH Cs{sub 0.2}CoO{sub 2}.0.63H{sub 2}O crystals grown from low temperature molten salt.

Tang, Horng Y. [Department of Applied Chemistry, National Chi Nan University, Puli, Taiwan (China)]. E-mail: hytang@ncnu.edu.tw; Lin, Hsiao Y. [Department of Applied Chemistry, National Chi Nan University, Puli, Taiwan (China); Wang, Ming J. [Institute of Astronomy and Astrophysics, Academia Sinica, Taipei, Taiwan (China); Liao, Ming Y. [Department of Applied Chemistry, National Chi Nan University, Puli, Taiwan (China); Hsu, Fon C. [Department of Materials Science, National Tsing Hua University, Hsinchu, Taiwan (China); Mok, Boon H. [Department of Materials Science, National Tsing Hua University, Hsinchu, Taiwan (China); Liu, Jean L. [Department of Applied Chemistry, National Chi Nan University, Puli, Taiwan (China); Beasley, Michael T. [Department of Applied Chemistry, National Chi Nan University, Puli, Taiwan (China); Sheu, Hwo S. [National Synchrotron Radiation Research Center, Hsinchu, Taiwan (China); Wu, Maw K. [Institute of Physics, Academia Sinica, Taipei, Taiwan (China)

2006-08-15

65

Chapter 1 Surface Structure and Reactivity of Iron Oxide–Water Interfaces  

Microsoft Academic Search

The surface structure and composition of the three distinct iron-(hydr)oxide systems, goethite (100), hematite (11¯02), and magnetite (111) were determined under hydrated conditions at room temperature using crystal truncation rod (CTR) analysis. The prediction of surface protonation states and the overall chemical plausibility of the experimental surface models are performed using a bond-valence (BV) analysis. Further analysis of the surface

Sanjit K. Ghose; Sarah C. Petitto; Kunaljeet S. Tanwar; Cynthia S. Lo; Peter J. Eng; Anne M. Chaka; Thomas P. Trainor

2007-01-01

66

Chapter 1 Surface Structure and Reactivity of Iron Oxide-Water Interfaces  

Microsoft Academic Search

The surface structure and composition of the three distinct iron-(hydr)oxide systems, goethite (1 0 0), hematite (1{bar 1}02), and magnetite (1 1 1) were determined under hydrated conditions at room temperature using crystal truncation rod (CTR) analysis. The prediction of surface protonation states and the overall chemical plausibility of the experimental surface models are performed using a bond-valence (BV) analysis.

S. K. Ghose; S. C. Petitto; K. S. Tanwar; C. S. Lo; P. J. Eng; A. M. Chaka; T. P. Trainor

2008-01-01

67

Defluoridation by Bacteriogenic Iron Oxides: Sorption Studies  

NASA Astrophysics Data System (ADS)

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 prediction of fluoride removal in a wide variety of groundwater systems. Sorption isotherms and affinity constants show the use of BIOS to be a promising technique for the remediation of fluoride in groundwater.

Evans, K.; Ferris, F.

2009-05-01

68

Electrodissolution of electrodeposited iron oxides  

SciTech Connect

Galvanostatic reduction of ferric oxide was studied in phosphate solutions over a range of pH values. The oxides were prepared on gold by anodic electrodeposition from dilute ferrous borate solution. With increased pH, the potential of the reduction arrests decreased and the charge associated with the arrest increased. A dependence of -60 mV/pH was observed except between pH 7.5 and 8.5 where the slope approximated -180 mV/pH. Above pH 7.5 the slope was consistent with the thermodynamic predicted slope of -180 mV/pH expected from reductive dissolution of ferric oxide forming soluble ferrous ions. At higher pH values, a slope of -60 mV/pH has been accounted for by oxide reduction to form a solid lower valent oxide.

Isaacs, H.S.; Ryan, M.P. [Brookhaven National Lab., Upton, NY (United States); Kalonousky, D.N. [State Univ. of New York, Stony Brook, NY (United States). Dept. of Materials Science; Virtanen, S. [Swiss Federal Inst. of Tech., Zurich (Switzerland). Inst. of Materials Chemistry and Corrosion

1996-12-31

69

Methane combustion over unsupported iron oxide catalysts  

Microsoft Academic Search

Bulk iron oxide, prepared by precipitation and by the citrates method, has been studied as an alternative catalyst for methane combustion. While hematite was the dominant phase in all the samples prepared, significant differences were observed regarding the activity and stability of the catalysts, depending on the preparation method. The catalysts prepared by precipitation presented higher surface areas and lower

A. L Barbosa; J Herguido; J Santamaria

2001-01-01

70

Chemical design of biocompatible iron oxide nanoparticles for medical applications.  

PubMed

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. PMID:23233377

Ling, Daishun; Hyeon, Taeghwan

2013-05-27

71

Starch vermicelli template for synthesis of magnetic iron oxide nanoclusters  

Microsoft Academic Search

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

Sanoe Chairam; Ekasith Somsook

2008-01-01

72

Bacterial methane oxidation in sea-floor gas hydrate: Significance to life in extreme environments  

Microsoft Academic Search

Samples of thermogenic hydrocarbon gases, from vents and gas hydrate mounds within a sea-floor chemosynthetic community on the Gulf of Mexico continental slope at about 540 m depth, were collected by research submersible. Our study area is characterized by low water temperature (mean =7 °C), high pressure (about 5400 kPa), and abundant structure II gas hydrate. Bacterial oxidation of hydrate-bound

Roger Sassen; Ian R. MacDonald; Norman L. Guinasso Jr.; Samantha Joye; Adolfo G. Requejo; Stephen T. Sweet; Javier Alcalá-Herrera; Debra A. Defreitas; David R. Schink

1998-01-01

73

Evolution of iron speciation during hydration of C{sub 4}AF  

SciTech Connect

It is now well accepted and demonstrated that calcium silicate, calcium aluminate and calcium sulfo aluminate (ettringite, AFm) phases exhibit a good capability to fix metals and metalloids. Unfortunately the role of minor phases and especially calcium-ferric aluminate phase, shorthand C{sub 4}AF is not well defined. In other systems like in soils or sediments iron phases play a key role in the fixation of pollutant. In cement sorption isotherms, indicated that various metals can be retained by the C{sub 4}AF hydrated products. Therefore the capabilities of those phase to retain heavy metal should not be neglected. Previous investigations have shown that the minerals formed during the hydration of C{sub 4}AF are similar to those formed from C3A (pure tri-calcium aluminate) under comparable conditions. Nevertheless no investigation was conducted at the molecular level and there is still a controversy whether Fe substitutes for Al in the hydrated minerals in whole or in part, or if it forms FeOOH clusters scattered throughout the matrix. In this context we have conducted XAS experiments using synchrotron radiation. It was found that the hydration of C{sub 4}AF forms C{sub 3}AH{sub 6} (hydrogarnet) in which Fe randomly substitutes for Al as well as an amorphous FeOOH phase. Intermediate products like AFm (i.e., an ill organized lamellar phase) are also formed but rapidly evolve to C{sub 3}AH{sub 6}; iron does not seem to be incorporated in the AFm structure.

Rose, J. [CEREGE Equipe physico-chimie des interfaces, UMR 6635 CNRS/Universite Paul Cezanne Aix-MarseilleIII-IFRE PSME 112, Europole Mediterraneen de l'Arbois, BP 80, 13545 Aix en Provence Cedex 4 (France) and ARDEVIE, Europole Mediterraneen de l'Arbois, BP 80, 13545 Aix en Provence Cedex 4 (France)]. E-mail: rose@cerege.fr; Benard, A. [ARDEVIE, Europole Mediterraneen de l'Arbois, BP 80, 13545 Aix en Provence Cedex 4 (France); INERIS, Domaine du Petit Arbois, BP 33, 13545 Aix en Provence (France); El Mrabet, S. [CEREGE Equipe physico-chimie des interfaces, UMR 6635 CNRS/Universite Paul Cezanne Aix-MarseilleIII-IFRE PSME 112, Europole Mediterraneen de l'Arbois, BP 80, 13545 Aix en Provence Cedex 4 (France); ARDEVIE, Europole Mediterraneen de l'Arbois, BP 80, 13545 Aix en Provence Cedex 4 (France); Masion, A. [CEREGE Equipe physico-chimie des interfaces, UMR 6635 CNRS/Universite Paul Cezanne Aix-MarseilleIII-IFRE PSME 112, Europole Mediterraneen de l'Arbois, BP 80, 13545 Aix en Provence Cedex 4 (France); ARDEVIE, Europole Mediterraneen de l'Arbois, BP 80, 13545 Aix en Provence Cedex 4 (France); Moulin, I. [LERM, 10, rue Mercoeur, 75011 Paris (France); Briois, V. [LURE Laboratoire pour l'Utilisation du Rayonnement Electromagnetique, Universite Paris-Sud, Orsay, France European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble Cedex (France); Olivi, L. [ELETTRA Sincrotrone Trieste S.c.p.A. S. S. 14, Km. 163.5 in AREA Science Park, I-34012 Basovizza, TS (Italy); Bottero, J.-Y. [CEREGE Equipe physico-chimie des interfaces, UMR 6635 CNRS/Universite Paul Cezanne Aix-MarseilleIII-IFRE PSME 112, Europole Mediterraneen de l'Arbois, BP 80, 13545 Aix en Provence Cedex 4 (France); ARDEVIE, Europole Mediterraneen de l'Arbois, BP 80, 13545 Aix en Provence Cedex 4 (France)

2006-07-01

74

Bacterial methane oxidation in sea-floor gas hydrate: Significance to life in extreme environments  

SciTech Connect

Samples of thermogenic hydrocarbon gases, from vents and gas hydrate mounds within a sea-floor chemosynthetic community on the Gulf of Mexico continental slope at about 540 m depth, were collected by research submersible. The study area is characterized by low water temperature (mean = 7 C), high pressure (about 5,400 kPa), and abundant structure II gas hydrate. Bacterial oxidation of hydrate-bound methane (CH{sub 4}) is indicated by three isotopic properties of gas hydrate samples. Relative to the vent gas from which the gas hydrate formed, (1) methane-bound methane is enriched in {sup 13}C by as much as 3.8% PDB (Peedee belemnite), (2) hydrate-bound methane is enriched in deuterium (D) by as much as 37% SMOW (standard mean ocean water), and (3) hydrate-bound carbon dioxide (CO{sub 2}) is depleted in {sup 13}C by as much as 22.4% PDB. Hydrate-associated authigenic carbonate rock is also depleted in {sup 13}C. Bacterial oxidation of methane is a driving force in chemosynthetic communities, and in the concomitant precipitation of authigenic carbonate rock that modifies sea-floor geology. Bacterial oxidation of hydrate-bound methane expands the potential boundaries of life in extreme environments.

Sassen, R.; MacDonald, I.R.; Guinasso, N.L. Jr.; Requejo, A.G.; Sweet, S.T.; Alcala-Herrera, J.; DeFreitas, D.A.; Schink, D.R. [Texas A and M Univ., College Station, TX (United States). Geochemical and Environmental Research Group] [Texas A and M Univ., College Station, TX (United States). Geochemical and Environmental Research Group; Joye, S. [Univ. of Georgia, Athens, GA (United States). Dept. of Marine Sciences] [Univ. of Georgia, Athens, GA (United States). Dept. of Marine Sciences

1998-09-01

75

Reduced iron induced nitric oxide and nitrous oxide emission.  

PubMed

Formation of the greenhouse gas nitrous oxide in water treatment systems is predominantly studied as a biological phenomenon. There are indications that also chemical processes contribute to these emissions. Here we studied the formation of nitric oxide (NO) and nitrous oxide (N(2)O) due to chemical nitrite reduction by ferrous iron (Fe(II)). Reduction of nitrite and NO coupled to Fe(II) oxidation was studied in laboratory-scale chemical experiments at different pH, nitrite and iron concentrations. The continuous measurement of both NO and N(2)O emission showed that nitrite reduction and NO reduction have different kinetics. Nitrite reduction shows a linear dependency on the nitrite concentration, implying first order kinetics in nitrite. The nitrite reduction seems to be an equilibrium based reaction, leading to a constant NO concentration in the liquid. The NO reduction rate is suggested to be most dependent on reactive surface availability and the sorption of Fe(II) to the reactive surface. The importance of emission of NO and N(2)O coupled to iron oxidation is exemplified by iron reduction experiments and several examples of environments where this pathway can play a role. PMID:21940030

Kampschreur, Marlies J; Kleerebezem, Robbert; de Vet, Weren W J M; van Loosdrecht, Mark C M

2011-11-15

76

Formulations for iron oxides dissolution  

DOEpatents

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.

Horwitz, Earl P. (Argonne, IL) [Argonne, IL; Chiarizia, Renato (Argonne, IL) [Argonne, IL

1992-01-01

77

Thin film photoelectrochemistry: Iron oxide  

Microsoft Academic Search

FeâOâ photoelectrodes offer advantages in respect to simplicity. However, at normal thickness, the efficiency is low. In this paper, the consequences of reducing the thickness of the oxide below that of the space-charge region is investigated. Allowing the light transmitted through the first electrode to be incident on further semitransparent electrodes should give a gain over a normal (ca. 1

K. Itoh; J. OM Bockris

1984-01-01

78

Thin film photoelectrochemistry: Iron oxide  

SciTech Connect

Fe/sub 2/O/sub 3/ photoelectrodes offer advantages in respect to simplicity. However, at normal thickness, the efficiency is low. In this paper, the consequences of reducing the thickness of the oxide below that of the space-charge region is investigated. Allowing the light transmitted through the first electrode to be incident on further semitransparent electrodes should give a gain over a normal (ca. 1 ..mu..m thick) electrode of ca. three times for ten successive electrodes. The theory is experimentally tested. It is quantitatively in agreement with experiment for values of the hole-solution transferrate constant (for water oxidation) of 6 x 10/sup -2/ cm s/sup -1/ M/sup -1/ and a model in which 1/4 of any change in applied p.d. occurs across the Helmholtz layer.

Itoh, K.; O'M Bockris, J.

1984-06-01

79

Synthesis of Iron-Iron Oxide Core Shell Nanoclusters for Environmental Applications  

Microsoft Academic Search

Nanoscale iron particles have gained much attention recently for their potential application in the remediation of a wide variety of common environmental contaminants. Fe0 iron nanoparticles are difficult to synthesize by conventional methods. Here we report room-temperature synthesis of iron-iron oxide core-shell nanoclusters using a new type of source. Oxide shells act as passivation layers preventing further oxidation of the

Antony Jiji; You Qiang; Baer R; David E. McCready; Engelhard H

2004-01-01

80

Uptake and metabolism of iron and iron oxide nanoparticles in brain astrocytes.  

PubMed

Astrocytes are considered key regulators of the iron metabolism of the brain. These cells are able to rapidly accumulate iron ions and various iron-containing compounds, store iron efficiently in ferritin and also export iron. The present short review summarizes our current knowledge of the molecular mechanisms involved in the handling of iron by astrocytes. Cultured astrocytes efficiently take up iron as ferrous or ferric iron ions or as haem by specific iron transport proteins in their cell membrane. In addition, astrocytes accumulate large amounts of iron oxide nanoparticles by endocytotic mechanisms. Despite the rapid accumulation of high amounts of iron from various iron-containing sources, the viability of astrocytes is hardly affected. A rather slow liberation of iron from accumulated haem or iron oxide nanoparticles as well as the strong up-regulation of the synthesis of the iron storage protein ferritin are likely to contribute to the high resistance of astrocytes to iron toxicity. The efficient uptake of extracellular iron by cultured astrocytes as well as their strong up-regulation of ferritin after iron exposure also suggests that brain astrocytes deal well with an excess of iron and protect the brain against iron-mediated toxicity. PMID:24256259

Hohnholt, Michaela C; Dringen, Ralf

2013-12-01

81

Reduction of Soluble Iron and Reductive Dissolution of Ferric Iron-Containing Minerals by Moderately Thermophilic Iron-Oxidizing Bacteria  

Microsoft Academic Search

Five moderately thermophilic iron-oxidizing bacteria, including representative strains of the three classified species (Sulfobacillus thermosulfidooxidans, Sulfobacillus acidophilus, and Acidimicrobium ferrooxidans), were shown to be capable of reducing ferric iron to ferrous iron when they were grown under oxygen limitation conditions. Iron reduction was most readily observed when the isolates were grown as mixotrophs or hetero- trophs with glycerol as an

TONI A. M. BRIDGE; D. BARRIE JOHNSON

1998-01-01

82

Oxidation Potentials in Iron and Steel Making  

NASA Astrophysics Data System (ADS)

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.

Matousek, J. W.

2013-11-01

83

Quantification of Iron Oxides and Hydroxides in Desert Aeolian Particles  

Microsoft Academic Search

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

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

2002-01-01

84

Synthesis and Characterization of Stable Iron–Iron Oxide Core–Shell Nanoclusters for Environmental Applications  

SciTech Connect

Iron–iron oxide core–shell nanoclusters are of great interest due to their potential applications as a remedy for environmental contamination. We report the room-temperature synthesis of core–shell iron–iron oxide nanoclusters using our novel cluster deposition system. Various types of measurements such as Transmission Electron Microscopy, X-ray Diffraction, X-ray Photon Spectroscopy, and Electron Energy Loss Spectroscopy are conducted in characterizing nanoclusters. Stable, monodispersive iron–iron oxide core–shell nanocrystals are identified.

Antony, Jiji; Qiang, You; Baer, Donald R.; Wang, Chong M.

2006-02-01

85

Cell toxicity of superparamagnetic iron oxide nanoparticles  

Microsoft Academic Search

The performance of nanoparticles for biomedical applications is often assessed by their narrow size distribution, suitable magnetic saturation and low toxicity effects. In this work, superparamagnetic iron oxide nanoparticles (SPIONs) with different size, shape and saturation magnetization levels were synthesized via a co-precipitation technique using ferrous salts with a Fe3+\\/Fe2+ mole ratio equal to 2. A parametric study is conducted,

M. Mahmoudi; A. Simchi; A. S. Milani; P. Stroeve

2009-01-01

86

Size and composition control of core-shell structured iron\\/iron-oxide nanoparticles  

Microsoft Academic Search

Metallic iron nanoparticles with a crystalline iron oxide shell were synthesized by the thermal decomposition of iron pentacarbonyl [Fe(CO)5] in octadecene in the presence of oleic acid and oleylamine. The effect of different synthetic parameters was investigated in details including the refluxing time and temperature, the injection temperature of iron precursor and the surfactant concentrations. The particles size can be

H. Khurshid; V. Tzitzios; Wanfeng Li; C. G. Hadjipanayis; G. C. Hadjipanayis

2010-01-01

87

Microanalysis of iron oxidation state in iron oxides using X Ray Absorption Near Edge Structure (XANES)  

NASA Technical Reports Server (NTRS)

An exploratory application of x ray absorption near edge structure (XANES) analysis using the synchrotron x ray microprobe was undertaken to obtain Fe XANES spectra on individual sub-millimeter grains in conventional polished sections. The experiments concentrated on determinations of Fe valence in a suite of iron oxide minerals for which independent estimates of the iron speciation could be made by electron microprobe analysis and x ray diffraction.

Sutton, S. R.; Delaney, J.; Bajt, S.; Rivers, M. L.; Smith, J. V.

1993-01-01

88

Iron oxidation state in hydrous rhyolites  

NASA Astrophysics Data System (ADS)

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+/?Fe 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+/?Fe 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.

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

2012-12-01

89

Synthesis and Characterization of Magnetic Iron Oxide Nanoparticles  

Microsoft Academic Search

This paper reports the synthesis and characterization of iron oxide nanoparticles and their assembly towards thin film materials. The results have provided important insights into the design of interfacial reactivities via iron nanoparticles for magnetic, catalytic and biological applications.

Lingyan Wang; Jin Luo; Mathew M. Maye; Quan Fan; Qiang Rendeng; JQ Wang; Mark H. Engelhard; Chong M. Wang; Yuehe Lin; EI Altman; Chuan-Jian Zhong

2005-01-01

90

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

NASA Astrophysics Data System (ADS)

This study investigates the potential for iron oxides to capture phosphate and arsenate. While iron oxides clearly bind phosphate and arsenate, one should not assume that iron oxides would straightforwardly trap these contaminants. Instead, iron oxides in shallow groundwater sediments undergo chemical transformations that could lead to the release of sorbed contaminants. Most notably, scientists commonly observe that the biologically driven reduction of ferric iron (Fe[III]) to ferrous iron (Fe[II]) releases phosphate and/or arsenate under some conditions. Despite this observation, it is generally unclear whether iron reduction will lead to greater or lesser mobility of phosphate and arsenic. This is because sorbed phosphate and arsenate may dissolve into the aqueous phase under iron-reducing conditions, thereby becoming more mobile, while under the same reducing conditions, phosphate and arsenate may precipitate with ferrous iron solids, thus decreasing their mobility. Further complications arise when the system is exposed to cycles of oxic and anoxic conditions. Under oxic conditions, ferrous iron will oxidize and form new iron oxides, while existing solid ferrous oxides will transform to new ferric oxides. In shallow groundwater, flooding and drought lead to cycles of oxic and anoxic conditions that could produce cyclic patterns in iron redox states and in the mobility of arsenic and phosphate. To better predict the evolution of arsenate and phosphate in the field, this research employs a simplified laboratory model. This study tracks the fate of arsenate and phosphate sorbed onto goethite, a common sediment component, as geobacter sulfurreducens reduces iron from Fe[III] to Fe[II], and after re-oxidation of reduced iron. By studying that particular phenomenon, this research sheds light on how microbes and one soil constituent influence the mobility of arsenate and phosphate contamination. The results of this study show that freshly precipitated ferrous iron solids can sequester arsenate and phosphate as they remove these anions from the aqueous phase and incorporate them into the matrix of freshly precipitated ferrous iron solids.

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

2008-12-01

91

Synthesis and characterization of iron, iron oxide and iron carbide nanostructures  

NASA Astrophysics Data System (ADS)

Magnetic iron oxide (Fe3O4 and ?-Fe2O3) and iron carbide (Fe3C) nanoparticles of different geometrical shapes: cubes, spheres, rods and plates, have been prepared by thermal decomposition of a mixture containing the metal precursor Fe(CO)5 and the stabilizer polyvinylpyrrolidone (PVP) at 300 °C in a sealed cell under inert atmosphere. The thermal decomposition process was performed for 4 or 24 h at ([PVP]/[Fe(CO)5]) (w/v) ratio of 1:1 or 1:5. Elemental iron nanospheres embedded within a mixture of amorphous and graphitic carbon coating were obtained by hydrogen reduction of the prepared iron oxide and iron carbide nanoparticles at 450 °C. The formation of the graphitic carbon phase at such a low temperature is unique and probably obtained by catalysis of the elemental iron nanoparticles. Changing the annealing time period and the ([PVP]/[Fe(CO)5]) ratio allowed control of the composition, size, size distribution, crystallinity, geometrical shape and magnetic properties of the different magnetic nanoparticles.

Snovski, Ron; Grinblat, Judith; Sougrati, Moulay-Tahar; Jumas, Jean-Claude; Margel, Shlomo

2014-01-01

92

Oxidation of iron powder in a fluidized bed reactor  

Microsoft Academic Search

The potential and technological viability of oxidation of iron powder for the production of high purity ferric oxide for soft ferrites have been discussed. Results of cold model studies have been incorporated. It has been shown that the conversion of iron powder to ferric oxide is a function of particle size, time and temperature of fluidization. The optimum properties have

M. G. Bodas; D. R. Dash; C. S. Sivaramakrishnan

1996-01-01

93

Homogeneous oxidation of water by iron complexes with macrocyclic ligands.  

PubMed

The activity of eleven separated iron complexes and nine in situ-generated iron complexes towards catalytic water oxidation have been examined in aqueous solutions with Ce(NH4)2(NO3)6 as the oxidant. Two iron complexes bearing tridentate and tetradentate macrocyclic ligands were found to be novel water oxidation catalysts. The one with tetradentate ligand exhibited a promising activity with a turnover number of 65 for oxygen evolution. PMID:24777911

Zhang, Biaobiao; Li, Fei; Yu, Fengshou; Cui, Honghua; Zhou, Xu; Li, Hua; Wang, Yong; Sun, Licheng

2014-06-01

94

Fabrication and characterization of iron oxide nanoparticles filled polypyrrole nanocomposites  

Microsoft Academic Search

The effect of iron oxide nanoparticle addition on the physicochemical properties of the polypyrrole (PPy) was investigated.\\u000a In the presence of iron oxide nanoparticles, PPy was observed in the form of discrete nanoparticles, not the usual network\\u000a structure. PPy showed crystalline structure in the nanocomposites and pure PPy formed without iron oxide nanoparticles. PPy\\u000a exhibited amorphous structure and nanoparticles were

Zhanhu Guo; Koo Shin; Amar B. Karki; David P. Young; Richard B. Kaner; H. Thomas Hahn

2009-01-01

95

Iron Oxide Materials Produced by Laser Pyrolysis  

NASA Astrophysics Data System (ADS)

The laser pyrolysis technique was employed in the production of magnetic iron oxide nanometric powders due to its capability of producing highly homogeneous nanoparticles in continuous form. This technique consists of the laser-driven rapid heating of an iron precursor in vapor phase in presence of oxygen. Different samples were prepared by changing the experimental conditions of synthesis. We found that high crystallinities and good magnetic properties are attained at high density of the laser power and strong oxidation. By the contrary, softer conditions using low laser densities and soft oxidation conditions give in general smaller and poorly ordered nanoparticles. The particles obtained were in the range of 2 to 9 nm in diameter (TEM). All of them were superparamagnetic at room temperature with saturation magnetization values in the interval of 4-38 emu/g-sample. The samples consist in Fe2O3 maghemite with carbon as the main impurity present on the surface in the form of C = O bonds.

Alexandrescu, R.; Bello, V.; Bouzas, V.; Costo, R.; Dumitrache, F.; García, M. A.; Giorgi, R.; Morales, M. P.; Morjan, I.; Serna, C. J.; Veintemillas-Verdaguer, S.

2010-10-01

96

Water clustering on nanostructured iron oxide films.  

PubMed

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. PMID:24979078

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

2014-01-01

97

The analysis of magnesium oxide hydration in three-phase reaction system  

NASA Astrophysics Data System (ADS)

In order to investigate the magnesium oxide hydration process in gas-liquid-solid (three-phase) reaction system, magnesium hydroxide was prepared by magnesium oxide hydration in liquid-solid (two-phase) and three-phase reaction systems. A semi-empirical model and the classical shrinking core model were used to fit the experimental data. The fitting result shows that both models describe well the hydration process of three-phase system, while only the semi-empirical model right for the hydration process of two-phase system. The characterization of the hydration product using X-Ray diffraction (XRD) and scanning electron microscope (SEM) was performed. The XRD and SEM show hydration process in the two-phase system follows common dissolution/precipitation mechanism. While in the three-phase system, the hydration process undergo MgO dissolution, Mg(OH)2 precipitation, Mg(OH)2 peeling off from MgO particle and leaving behind fresh MgO surface.

Tang, Xiaojia; Guo, Lin; Chen, Chen; Liu, Quan; Li, Tie; Zhu, Yimin

2014-05-01

98

Sputtered iron oxide/silicon heterostructures  

NASA Astrophysics Data System (ADS)

Sputtered Fe3O4 films are shown to form rectifying junctions to p-type silicon but ohmic contacts to n-type Si. It is pointed out that ohmic contacts to the Fe3O4 can be provided by Au, Al, or spray-deposited ITO. The redox couple Fe(CN)6(3-)/Fe(CN)6(4-) also seems to make an effective ohmic contact to this iron oxide. It is found that the photovoltaic and electrical characteristics of the Fe3O4/p-Si heterojunction depend strongly on the Fe3O4 film thickness.

Kardauskas, M. J.; Fonash, S. J.; Ashok, S.; Krishnaswamy, S. V.; Messier, R. F.

1981-03-01

99

Mössbauer study of iron oxide modified montmorillonite  

NASA Astrophysics Data System (ADS)

Montmorillonite particles were modified by iron oxides using the precipitation process with the aim to monitor the differences in the structural and magnetic properties of intercalated and adsorbed Fe3+. The Mössbauer spectra recorded at 5 K in zero and 6 T external fields, IR spectra and TG curves measured in zero and 32 mT fields identified the ferrihydrite pillars in an interlayer space of the montmorillonite structure and ?-Fe2O3 nanoparticles adsorbed on the mineral surface. The temperature dependent Mössbauer spectra (25 300 K) reflect the superparamagnetic behaviour of maghemite nanoparticles and ferrihydrite pillars with the blocking temperatures of about 80 and 25 K, respectively.

Bartonkova, H.; Mashlan, M.; Zboril, R.; Pechousek, J.; Schneeweiss, O.; Martinec, P.

2005-09-01

100

Core/shell structured iron/iron-oxide nanoparticles as excellent MRI contrast enhancement agents  

NASA Astrophysics Data System (ADS)

We report the use of metallic iron-based nanoparticles for magnetic resonance imaging (MRI) applications. Core/shell structured iron-based nanoparticles prepared by thermally decomposing organo-metallic compounds of iron at high temperature in the presence of hydrophobic surfactants were coated and stabilized in the aqueous solvent using the newly developed polysiloxane PEO-b-P?MPS (poly(ethylene oxide)-block-poly (? methacryloxypropyl trimethyl oxysilane)) diblock copolymers. Particles are well suspended in water and retain their core-shell morphology after coating with the copolymer. In comparison to the conventionally used iron-oxide nanoparticles, core/shell structured iron/iron-oxide nanoparticles offer a much stronger T2 shortening effect than that of iron-oxide with the same core size due to their better magnetic properties.

Khurshid, Hafsa; Hadjipanayis, Costas G.; Chen, Hongwei; Li, Wanfeng; Mao, Hui; Machaidze, Revaz; Tzitzios, Vasilis; Hadjipanayis, George C.

2013-04-01

101

Organic phase synthesis of monodisperse iron oxide nanocrystals using iron chloride as precursor.  

PubMed

Monodisperse iron oxide nanocrystals were synthesized by a simplified method using iron chloride as precursor. In the presence of Cl ions, the as-produced iron oxide nanocrystals preferred a cubic shape with {100} facets exposed. The function of halogens including Cl and Br ions on stabilizing {100} facets of spinel structured iron oxides, rather than the regulation of thermolysis kinetics and surfactants, was found influential on the shape control of nanocubes in this organic phase approach. The synthesis can be also extended for cobalt ferrite nanocubes and cobalt oxide polyhedrons. PMID:20648303

Xu, Zhichuan; Shen, Chengmin; Tian, Yuan; Shi, Xuezhao; Gao, H-J

2010-06-01

102

Synthesis of complex oxide phases by using of low hydrated niobium and tantalum hydroxides  

Microsoft Academic Search

Promising method of complex oxide phases synthesis by using low hydrated hydroxides of niobium and tantalum (Nb,Ta)Ox(OH)5?x·mH2O precursors of high reactivity and sorption ability was developed. Precursors, intermediate products of synthesis and target materials were studied by thermogravimetric analysis, infrared spectroscopy and X-ray diffraction. Sorption process of magnesium and lead cations by niobium low hydrated hydroxide from acetic solution allows

D. Drobot; E. Nikishina; E. Lebedeva; A. Novoselov; A. Yoshikawa

2008-01-01

103

Hydrated oxide film growth on aluminium alloys immersed in warm water  

Microsoft Academic Search

The growth of hydrated oxide films on 2024 bare and 7075 clad aluminium alloys immersed in deionized water at temperatures of 40 and 50 °C for periods up to a couple of hours was studied using grazing angle FTIR, weight gain measurements, high resolution SEM and AFM. The results show that a porous oxide structure, likely to be very suitable

P. R. Underhill; A. N. Rider

2005-01-01

104

Ecology of neutrophilic iron-oxidizing bacteria in wetland soils  

Microsoft Academic Search

Wetland ecosystems are important as sites of rapid biogeochemical cycling of bioactive elements, among which iron features prominently. The redox cycling of iron exerts a strong influence on soil chemistry and the metabolism of plants and microorganisms. Studies have shown that bacteria play an important role in the process of iron oxidation in wetlands. This study explores the diversity and

J. Wang

2011-01-01

105

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

PubMed

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 ?-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. PMID:23249219

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

2013-01-15

106

Description and classification of uranium oxide hydrate sheet anion topologies  

SciTech Connect

The sheets of uranyl ions (U{sup 6+}O{sub 2}){sup 2+} in the structures of all uranyl oxide hydrates (UOH) (and the structurally related {alpha}- and {beta} forms of U{sub 3}O{sub 8}) are based on only four structural unit chains. Each sheet type may be reduced to its underlying sheet anion topology to determine the chains present within each topology and to describe the structural relationships among these phases. Each sheet type is described by a chain stacking sequence. The four chain types required to construct the UOH sheet anion topologies are the {bold H}-chains, the {bold R}-chain, the {bold P}-chain, and the directional {open_quotes} arrowhead{close_quotes} chains denoted by {bold U} and {bold D}. The {bold H}-chain is found only in the sheet anion topology of {alpha}-UO{sub 2}(OH){sub 2} and consists of hexagonal sites sharing opposing edges. In {alpha}-UO{sub 2}(OH){sub 2}, all hexagons are populated with uranyl ions. The {open_quotes} arrowhead{close_quotes} chain is composed of pentagonal sites populated with uranyl ions and sharing edges and alternating with vacant triangular sites. Arrowhead chains are present in the sheet anion topologies of all other UOH sheets. Arrowhead chains are directional and can occur in both {bold U} and {bold D} {open_quotes} senses{close_quotes} within a single anion topology. The {bold P}-chain consists of edge-sharing pentagonal sites populated with uranyl ions forming a zigzag chain. The {bold P}-chain is flanked on both sides by arrowhead chains of the same {open_quotes} sense{close_quotes}. The remaining structural unit is a discontinuous {open_quotes} chain{close_quotes} of rhombic sites. This {open_quotes}{bold R}-chain{close_quotes} is produced when nested; adjacent {bold U} and {bold D} {open_quotes} arrowhead{close_quotes} chains are translated diagonally. (Abstract Truncated)

Miller, M.L. [Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, New Mexico 87131 (United States); Finch, R.J. [Department of Geological Sciences, University of Manitoba, Winnipeg, Manitoba R3T 2N2 (Canada); Burns, P.C.; Ewing, R.C. [Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, New Mexico 87131 (United States)

1996-12-01

107

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

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Cobalt iron manganese oxide, carboxylic acid-modified...Chemical Substances § 721.10529 Cobalt iron manganese oxide, carboxylic acid-modified...substance identified generically as cobalt iron manganese oxide, carboxylic...

2013-07-01

108

Size and composition control of core-shell structured iron/iron-oxide nanoparticles  

NASA Astrophysics Data System (ADS)

Metallic iron nanoparticles with a crystalline iron oxide shell were synthesized by the thermal decomposition of iron pentacarbonyl [Fe(CO)5] in octadecene in the presence of oleic acid and oleylamine. The effect of different synthetic parameters was investigated in details including the refluxing time and temperature, the injection temperature of iron precursor and the surfactant concentrations. The particles size can be tuned by controlling the injection temperature of iron precursor. Particle composition was adjusted by controlling the refluxing time. Both XRD diffraction and magnetic measurements indicated that these particles are very stable against oxidation which was further evidenced by microstructure analysis.

Khurshid, H.; Tzitzios, V.; Li, Wanfeng; Hadjipanayis, C. G.; Hadjipanayis, G. C.

2010-05-01

109

Synthesis and magnetic characterizations of uniform iron oxide nanoparticles  

NASA Astrophysics Data System (ADS)

Uniform iron oxide nanoparticles with a cubic shape were prepared by the decomposition of homemade iron oleate in 1-octadecene with the presence of oleic acid. The particle shape and size uniformity are sensitive to the quantity of oleic acid. XRD, HRTEM and SAED results indicated that the main phase content of as-prepared iron oxide nanoparticles is Fe3O4 with an inverse spinel structure. Magnetic measurements revealed that the as-prepared iron oxide nanoparticles display a ferromagnetic behavior with a blocking temperature of 295 K. At low temperatures the magnetic anisotropy of the aligned nanoparticles caused the appearance of a hysteresis loop.

Jiang, FuYi; Li, XiaoYi; Zhu, Yuan; Tang, ZiKang

2014-06-01

110

Battles with iron: manganese in oxidative stress protection.  

PubMed

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. PMID:22247543

Aguirre, J Dafhne; Culotta, Valeria C

2012-04-20

111

Retorting oil shale with iron oxide impregnated porous pellets  

Microsoft Academic Search

Oil shale is mixed and retorted with hot porous pellets. The porous pellets have a surface area of at least 10 square meters per gram. Iron oxide is deposited or impregnated on the pellet surface area prior to retorting. The iron oxide imparts special properties to the pellets. After retorting, the pellets are separated from the processed oil shale solids,

Beck

1979-01-01

112

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...

113

Thermosensitive liposomes entrapping iron oxide nanoparticles for controllable drug release  

Microsoft Academic Search

Iron oxide nanoparticles can serve as a heating source upon alternative magnetic field (AMF) exposure. Iron oxide nanoparticles can be mixed with thermosensitive nanovehicles for hyperthermia-induced drug release, yet such a design and mechanism may not be suitable for controllable drug release applications in which the tissues are susceptible to environmental temperature change such as brain tissue. In the present

Lin-Ai Tai; Pi-Ju Tsai; Yu-Chao Wang; Yu-Jing Wang; Leu-Wei Lo; Chung-Shi Yang

2009-01-01

114

Iron oxides as a cause of GPR reflections  

Microsoft Academic Search

Iron oxides frequently occur as secondary precipi- tates in both modern and ancient sediments and may form bands or irregular patterns. We show from time- domain reflectometry (TDR) field studies that goethite iron-oxide precipitates significantly lower the electro- magnetic wave velocity of sediments. Measured varia- tions in magnetic permeability do not explain this de- crease. The TDR measurements and a

Remke L. Van Dam; Wolfgang Schlagerz; Mark J. Dekkers; Johan A. Huisman

2002-01-01

115

Biogeochemistry of Iron Oxidation in a Circumneutral Freshwater Habitat  

Microsoft Academic Search

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

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

2007-01-01

116

Biogeochemistry of iron oxidation in a circumneutral freshwater habitat  

Microsoft Academic Search

Iron(II) oxidation in natural waters at circumneutral pH, often regarded as an abiotic process, is frequently biologically mediated at iron-rich redox gradients. West Berry Creek, a small circumneutral tributary that flows 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

Owen W. Duckworth; Sara J. M. Holmström; Jasquelin Peña; Garrison Sposito

2009-01-01

117

PRECIPITATION CHEMISTRY OF MAGNESIUM SULFITE HYDRATES IN MAGNESIUM OXIDE SCRUBBING  

EPA Science Inventory

The report gives results of laboratory studies defining the precipitation chemistry of MgSO3 hydrates. The results apply to the design of Mg-based scrubbing processes for SO2 removal from combustion flue gas. In Mg-based scrubbing processes, MgSO3 precipitates as either trihydrat...

118

Enhancement of properties of red iron oxide – aluminium oxide solid solutions anticorrosive pigments  

Microsoft Academic Search

Purpose – Several solid solution combinations of aluminium oxide and iron oxide, for the preparation of a new pigment, were investigated to study the effect of aluminium oxide to iron oxide ratio on various properties of the resulting pigments. Design\\/methodology\\/approach – The conditions for the preparation of the pigments via solid solution interaction at 1,000°C had been estimated. Characterisation of

N. M. Ahmed; M. M. Selim

2005-01-01

119

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

Microsoft Academic Search

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

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

2008-01-01

120

A Simple Way to Synthesize Superparamagnetic Iron Oxide Nanoparticles in Air Atmosphere: Iron Ion Concentration Effect  

Microsoft Academic Search

We have synthesized iron oxide nanoparticles in air atmosphere by coprecipitation. The ratio of was fixed at 2\\/3. The total amount of iron ions in the solution was varied from 250 mmol to 12.5 mmol. X-ray diffraction (XRD) patterns showed the characteristic peaks of iron oxide phases. We observed that the crystallinity reduced and particle sizes calculated from XRD patterns

Oznur Karaagac; Hakan Kockar; Seda Beyaz; Taner Tanrisever

2010-01-01

121

Evaluation of tumoral enhancement by superparamagnetic iron oxide particles: comparative studies with ferumoxtran and anionic iron oxide nanoparticles  

Microsoft Academic Search

This study was designed to compare tumor enhancement by superparamagnetic iron oxide particles, using anionic iron oxide nanoparticles (AP) and ferumoxtran. In vitro, relaxometry and media with increasing complexity were used to assess the changes in r2 relaxivity due to cellular internalization. In vivo, 26 mice with subcutaneously implanted tumors were imaged for 24 h after injection of particles to describe

P. Y. Brillet; F. Gazeau; A. Luciani; B. Bessoud; C.-A. Cuénod; N. Siauve; J.-N. Pons; J. Poupon; O. Clément

2005-01-01

122

Magnetic behavior of free-iron and iron oxide clusters  

NASA Astrophysics Data System (ADS)

We report the first measurement of the magnetic properties of isolated iron-atom clusters ranging in size from 2 to 17 atoms as well as the magnetic behavior of the monoxides and dioxides of (2-7)-atom iron clusters. Production of metal clusters is initiated by laser vaporization of an iron rod inside the throat of a high-pressure pulsed nozzle. The neutral metal cluster beam passes through a Stern-Gerlach magnet and the deflected beam is detected by spatially resolved time-of-flight photoionization mass spectrometry. From our analysis we conclude that the spin per atom of iron clusters is at least that of bulk iron, suggesting these small clusters are the precursors to bulk ferromagnetic iron.

Cox, D. M.; Trevor, D. J.; Whetten, R. L.; Rohlfing, E. A.; Kaldor, A.

1985-12-01

123

Magnetic behavior of free-iron and iron oxide clusters  

Microsoft Academic Search

We report the first measurement of the magnetic properties of isolated iron-atom clusters ranging in size from 2 to 17 atoms as well as the magnetic behavior of the monoxides and dioxides of (2-7)-atom iron clusters. Production of metal clusters is initiated by laser vaporization of an iron rod inside the throat of a high-pressure pulsed nozzle. The neutral metal

D. M. Cox; D. J. Trevor; R. L. Whetten; E. A. Rohlfing; A. Kaldor

1985-01-01

124

Microbially Induced Iron Oxidation: What, Where, How  

SciTech Connect

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.

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

2000-08-15

125

Multiple hearth furnace for reducing iron oxide  

DOEpatents

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).

Brandon, Mark M. (Charlotte, NC); True, Bradford G. (Charlotte, NC)

2012-03-13

126

Biocompatible multishell architecture for iron oxide nanoparticles.  

PubMed

The coating of super-paramagnetic iron oxide nanoparticles (SPIONs) with multiple shells is demonstrated by building a layer assembled from carboxymethyldextran and poly(diallydimethylammonium chloride). Three shells are produced stepwise around aggregates of SPIONs by the formation of a polyelectrolyte complex. A growing particle size from 96 to 327?nm and a zeta potential in the range of +39 to -51?mV are measured. Microscopic techniques such as TEM, SEM, and AFM exemplify the core-shell structures. Magnetic force microscopy and vibrating sample magnetometer measurements confirm the architecture of the multishell particles. Cell culture experiments show that even nanoparticles with three shells are still taken up by cells. PMID:23161745

Wotschadlo, Jana; Liebert, Tim; Clement, Joachim H; Anspach, Nils; Höppener, Stephanie; Rudolph, Tobias; Müller, Robert; Schacher, Felix H; Schubert, Ulrich S; Heinze, Thomas

2013-01-01

127

Artificial meteor ablation studies - Iron oxides.  

NASA Technical Reports Server (NTRS)

Artificial meteor ablation was performed on natural minerals composed predominantly of magnetite and hematite by using an arc-heated plasma stream of air. Analysis indicates that most of the ablated debris was composed of two or more minerals. Wustite, a metastable mineral, was found to occur as a common product. The 'magnetite' sample, which was 80% magnetite, 14% hematite, 4% apatite, and 2% quartz, yielded ablated products consisting of more than 12 different minerals. Magnetite occurred in 91% of the specimens examined, hematite in 16%, and wustite in 30%. The 'hematite' sample, which was 96% hematite and 3% quartz, yielded ablated products consisting of more than 13 different minerals. Hematite occurred in 47% of the specimens examined, magnetite in 60%, and wustite in 28%. The more volatile elements (Si, P, and Cl) were depleted by about 50%. This study has shown that artificially created ablation products from iron oxides exhibit unique properties that can be used for identification.

Blanchard, M. B.

1972-01-01

128

Kinetics of zero valent iron nanoparticle oxidation in oxygenated water.  

PubMed

Zero valent iron (ZVI) nanoparticles are versatile in their ability to remove a wide variety of water contaminants, and ZVI-based bimetallic nanoparticles show increased reactivity above that of ZVI alone. ZVI nanoparticles degrade contaminants through the reactive species (e.g., OH*, H(2(g)), H(2)O(2)) that are produced during iron oxidation. Measurement and modeling of aqueous ZVI nanoparticle oxidation kinetics are therefore necessary to optimize nanoparticle design. Stabilized ZVI and iron-nickel nanoparticles of approximately 150 nm in diameter were synthesized through solution chemistry, and nanoparticle oxidation kinetics were determined via measured mass change using a quartz crystal microbalance (QCM). Under flowing aerated water, ZVI nanoparticles had an initial exponential growth behavior indicating surface-dominated oxidation controlled by migration of species (H(2)O and O(2)) to the surface. A region of logarithmic growth followed the exponential growth which, based on the Mott-Cabrera model of thin oxide film growth, suggests a reaction dominated by movement of species (e.g., iron cations and oxygen anions) through the oxide layer. The presence of ethanol or a nickel shell on the ZVI nanoparticles delayed the onset of iron oxidation and reduced the extent of oxidation. In oxygenated water, ZVI nanoparticles oxidized primarily to the iron oxide-hydroxide lepidocrocite. PMID:23130994

Greenlee, Lauren F; Torrey, Jessica D; Amaro, Robert L; Shaw, Justin M

2012-12-01

129

Interaction of poly-N-vinylpyrrolidone with hydrated metal oxides  

Microsoft Academic Search

On the basis of data of IR spectroscopy and powder diffraction analysis, an aqueous solution of poly-N-vinylpyrrolidone was\\u000a shown to interact with hydrated alumina and zirconia synthesized from corresponding metal chlorides by means of sol-gel technology.\\u000a A change was shown in the nature of polymer interaction with individual components and their binary mixture at different annealing\\u000a temperatures. Different mechanisms of

T. M. Zima; I. A. Vorsina; N. Z. Lyakhov

2009-01-01

130

Stabilization and functionalization of iron oxide nanoparticles for biomedical applications.  

PubMed

Superparamagnetic iron oxide nanoparticles (NPs) are used in a rapidly expanding number of research and practical applications in the biomedical field, including magnetic cell labeling separation and tracking, for therapeutic purposes in hyperthermia and drug delivery, and for diagnostic purposes, e.g., as contrast agents for magnetic resonance imaging. These applications require good NP stability at physiological conditions, close control over NP size and controlled surface presentation of functionalities. This review is focused on different aspects of the stability of superparamagnetic iron oxide NPs, from its practical definition to its implementation by molecular design of the dispersant shell around the iron oxide core and further on to its influence on the magnetic properties of the superparamagnetic iron oxide NPs. Special attention is given to the selection of molecular anchors for the dispersant shell, because of their importance to ensure colloidal and functional stability of sterically stabilized superparamagnetic iron oxide NPs. We further detail how dispersants have been optimized to gain close control over iron oxide NP stability, size and functionalities by independently considering the influences of anchors and the attached sterically repulsive polymer brushes. A critical evaluation of different strategies to stabilize and functionalize core-shell superparamagnetic iron oxide NPs as well as a brief introduction to characterization methods to compare those strategies is given. PMID:21629911

Amstad, Esther; Textor, Marcus; Reimhult, Erik

2011-07-01

131

Contribution of the hydration force to vesicle adhesion on titanium oxide.  

PubMed

Titanium oxide is a biocompatible material that supports vesicle adhesion. Depending on experimental parameters, adsorbed vesicles remain intact or rupture spontaneously. Vesicle rupture has been attributed to electrostatic attraction between vesicles and titanium oxide, although the relative contribution of various interfacial forces remains to be clarified. Herein, we investigated the influence of vesicle surface charge on vesicle adsorption onto titanium oxide and observed that electrostatic attraction is insufficient for vesicle rupture. Following this line of evidence, a continuum model based on the DLVO forces and a non-DLVO hydration force was applied to investigate the role of different interfacial forces in modulating the lipid-substrate interaction. Within an experimentally significant range of conditions, the model shows that the magnitude of the repulsive hydration force strongly influences the behavior of adsorbed vesicles, thereby supporting that the hydration force makes a strong contribution to the fate of adsorbed vesicles on titanium oxide. The findings are consistent with literature reports concerning phospholipid assemblies on solid supports and nanoparticles and underscore the importance of the hydration force in influencing the behavior of phospholipid films on hydrophilic surfaces. PMID:24796732

Jackman, Joshua A; Zan, Goh Haw; Zhao, Zhilei; Cho, Nam-Joon

2014-05-20

132

Iron oxide amended biosand filters for virus removal.  

PubMed

Laboratory studies were performed to determine if the addition of iron oxides throughout biosand filter (BSF) media would increase virus removal due to adsorption. The proposed mechanism is electrostatic adsorption of negatively charged virion particles to positively charged iron oxides formed during the corrosion of zerovalent iron. Initial tests conducted using continuous flow, small-scale glass columns showed high MS2 bacteriophage removal in an iron-amended sand column (5log10) compared to a sand-only column (0.5log10) over 20 pore volumes. Additionally, two experiments with a column containing iron particles revealed 4log10 and 5log10 removal of rotavirus in the presence of 20 mg/L total organic carbon. Full-scale BSFs with iron particles removed>4log10 MS2 for the duration of the experiment (287 days), while BSF with steel wool removed>4log10 MS2 for the first 160 days. Plug flow for the BSF was shown to depend on uniformity between the iron oxide material and sand media grains. The results suggest that the duration of effective virus removal by iron-amended biosand filtration depends on source water conditions and the quantity and composition of iron material added. Overall, this study provides evidence that iron-amended BSFs may advance the field of point-of-use technologies and bring relief to millions of people suffering from waterborne diseases. PMID:21708394

Bradley, Ian; Straub, Anthony; Maraccini, Peter; Markazi, Sheila; Nguyen, Thanh H

2011-10-01

133

Hydration thermodynamics of pyrochlore structured oxides from TG and first principles calculations.  

PubMed

In this contribution we investigate trends in the defect chemistry and hydration thermodynamics of rare-earth pyrochlore structured oxides, RE(2)X(2)O(7) (RE = La-Lu and X = Ti, Sn, Zr and Ce). First principles density functional theory (DFT) calculations have been performed to elucidate trends in the general defect chemistry and hydration enthalpy for the above-mentioned series. Further, to justify the use of such theoretical methods, the hydration properties of selected compositions were studied by means of thermogravimetric measurements. Both DFT calculations and TG measurements indicate that the hydration enthalpy becomes less exothermic with decreasing radii of RE ions within the RE(2)X(2)O(7) series (X = Ti, Sn, Zr and Ce), while it is less dependent on the X site ion. The observed hydration trends are discussed in connection with trends in the stability of both protons and oxygen vacancies and changes in the electronic density of states and bonding environment through the series. Finally, the findings are discussed with respect to existing correlations for other binary and ternary oxides. PMID:23001186

Bjørheim, Tor S; Besikiotis, Vasileios; Haugsrud, Reidar

2012-11-21

134

Interaction of fluorescent sensor with superparamagnetic iron oxide nanoparticles.  

PubMed

To sense superparamagnetic iron oxides (Fe2O3 and Fe3O4) nanocrystals a sensitive bioactive phenanthroimidazole based fluorescent molecule, 2-(4-fluorophenyl)-1-phenyl-1H-phenanthro [9,10-d] imidazole has been designed and synthesized. Electronic spectral studies show that phenanthroimidazole is bound to the surface of iron oxide semiconductors. Fluorescent enhancement has been explained on the basis of photo-induced electron transfer (PET) mechanism and apparent binding constants have been deduced. Binding of phenanthroimidazole with iron oxide nanoparticles lowers the HOMO and LUMO energy levels of phenanthroimidazole molecule. Chemical affinity between the nitrogen atom of the phenanthroimidazole and Fe(2+) and Fe(3+) ions on the surface of the nano-oxide may result in strong binding of the phenanthroimidazole derivative with the nanoparticles. The electron injection from the photoexcited phenanthroimidazole to the iron oxides conduction band explains the enhanced fluorescence. PMID:23562745

Karunakaran, Chockalingam; Jayabharathi, Jayaraman; Sathishkumar, Ramalingam; Jayamoorthy, Karunamoorthy

2013-06-01

135

PhotoChemical Synthesis of Iron Oxide Nanowires Induced by Pulsed Laser Ablation of Iron Powder in Liquid Media  

Microsoft Academic Search

Iron oxide nanowires are synthesized by photochemical method through nanosecond pulsed laser ablation of iron powder in liquid media. The synthesis is tried using various wavelengths (248 and 532 nm) of pulsed laser at different liquids (water, ethanol, methanol, isopropanol and glycol). The solution of iron oxide nanowires is obtained only in methanol when the iron powder (size 60 mu

S. Mollah; S. J. Henley; C. E. Giusca; S. R. P. Silva

2010-01-01

136

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

Microsoft Academic Search

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

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

2010-01-01

137

Redox reactions in liquid plasma during iron oxide and oxide-hydroxide nanoparticles synthesis  

Microsoft Academic Search

A new synthesis method of iron oxide and iron oxide-hydroxide nanoparticles by pulsed liquid plasma process is presented. The redox reaction rates in liquid phase depend on the relative number densities of oxygen and hydrogen atoms produced in plasma gas phase and on the injected energy per pulse. The oxidation rate was higher than the reduction one in both regimes

M. A. Bratescu; N. Saito; O. Takai

138

Iron species-mediated dopamine oxidation, proteasome inhibition, and dopaminergic cell demise: implications for iron-related dopaminergic neuron degeneration.  

PubMed

Iron species have been suggested to be highly involved in the pathogenesis of Parkinson disease. However, the detailed mechanism of iron-induced dopaminergic degeneration is still unclear. In this study, we demonstrate that free iron ions (trivalent or bivalent) and iron ions in stable complex with cyanide ions (K(4)Fe(CN)(6) and K(3)Fe(CN)(6)) can induce dopamine (DA) oxidation with different profiles and subsequently lead to proteasome inhibition and even dopaminergic MN9D cell demise via different mechanisms. The free iron ions could mediate extensive DA oxidation in an iron-DA complex-dependent manner. However, iron ions in stable complex with cyanide ions could not induce, or could induce only brief, DA oxidation. Deferoxamine, a specific iron ion chelator, could disrupt iron-DA complex formation and thus abrogate free iron ion-catalyzed DA oxidation and subsequent cell toxicity. Glutathione could neither disrupt iron-DA complex formation nor influence free iron ion-catalyzed DA oxidation but could protect against iron-mediated toxicity via detoxification of toxic by-products of iron-mediated DA oxidation. The resulting DA oxidation could inhibit chymotrypsin-like, trypsin-like, and caspase-like proteasome activities. However, we demonstrated that oxidative damage was not the major toxic mechanism of MN9D cell degeneration, but it was the DA quinones derived from iron-induced DA oxidation that contributed significantly to proteasome inhibition and even dopaminergic cell demise. PMID:20854902

Zhou, Zhi Dong; Lan, Yu Hong; Tan, Eng King; Lim, Tit Meng

2010-12-15

139

Preparation of nanosized iron oxide and its application in low temperature CO oxidation  

Microsoft Academic Search

A method to prepare iron oxide material which has a higher surface area and nanosized particle was developed. It was used as a catalyst for CO oxidation at low temperature. Iron oxide materials were prepared by precipitation under constant pH value. The effects of preparation parameters, such as iron salt (FeCl3, Fe(NO3)3 and FeCl2), pH value (between 8 and 12),

Hsin-Yu Lin; Yu-Wen Chen; Wei-Jye Wang

2005-01-01

140

Synthesis and heating effect of iron\\/iron oxide composite and iron oxide nanoparticles  

Microsoft Academic Search

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 FeCl3 within a NaBH4 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

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

2007-01-01

141

Methane partial oxidation in iron zeolites: theory versus experiment  

Microsoft Academic Search

The conversion of methane to methanol over zeolitic ?-oxygen sites has been demonstrated using Fe-ZSM-5. To discriminate between mono- and poly-nuclear active sites, we prepared the [Fe]-ZEO with iron in the ZEOlite lattice via direct synthesis and Fex-ZEO, by dispersion of xwt.% iron on the ZEOlite. Shape-selective formation of nano-clusters of iron oxides with various sizes is realized inside the

P. P. Knops-Gerrits; W. A. Goddard

2001-01-01

142

Synthesis of complex oxide phases by using of low hydrated niobium and tantalum hydroxides  

SciTech Connect

Promising method of complex oxide phases synthesis by using low hydrated hydroxides of niobium and tantalum (Nb,Ta)O{sub x}(OH){sub 5-x}.mH{sub 2}O precursors of high reactivity and sorption ability was developed. Precursors, intermediate products of synthesis and target materials were studied by thermogravimetric analysis, infrared spectroscopy and X-ray diffraction. Sorption process of magnesium and lead cations by niobium low hydrated hydroxide from acetic solution allows obtaining PbMg{sub 1/3}Nb{sub 2/3}O{sub 3} complex perovskite without any secondary phase.

Drobot, D.; Nikishina, E.; Lebedeva, E. [Lomonosov Moscow State Academy of Fine Chemical Technology, Moscow (Russian Federation); Novoselov, A. [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577 (Japan)], E-mail: anvn@tagen.tohoku.ac.jp; Yoshikawa, A. [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577 (Japan)

2008-05-06

143

Magnetic Characterization of Iron Oxide Cross Linked Hydro gels  

NASA Astrophysics Data System (ADS)

Magnetic hydro gels have potential applications in drug delivery, cells sorting, sensors, and actuating technologies. Iron oxide alginate nanocomposites were synthesized following the method of Kroll et al^1 by cross linking sodium alginate with Fe^2+ and Fe^3+ in methanol: water. The ion-cross linked alginate hydro gels are oxidized in an alkaline solution. The resulting hydro gel consists of iron oxide cross linked alginate. The alginate hydro gels are inert to the reaction conditions and therefore the reaction sequence can be repeated. The multiple loadings result in an increase in the amount of iron oxide and the size of the iron oxide nanoparticles in the cross linked hydro gels. The third and sixth loaded iron oxide alginate hydro gels were dried and characterized by X-ray diffraction (XRD), Transmission Electron Microscopy (TEM), and Superconducting Quantum Interference Device (SQUID) magnetometry. The XRD patterns have characteristic features of ?- Fe_2O3 or Fe_3O4 phases. The average particle size, calculated from the XRD peaks, for third loaded iron oxide alginate was 2 nm. The zero-field-cooled and field-cooled SQUID measurements show the iron oxide nanoparticles are superparamagnetic with blocking temperature (T_B) of approximately 35 K. Above the blocking temperature, the inverse susceptibility versus temperature relationship does not follow the Curie-Weiss law, indicating strong inter-particle interactions. The M vs. H data above the blocking temperature was fitted with a modified Langevin function to obtain additional information about the iron oxide particle size. Details of the relationship between coercive field and temperature as well as the particle size distribution obtained from XRD and TEM measurements will be presented. *Research supported by NSF grant # DGE ˜980720 **Supported by NSF REU grant # EEC-0097736 ^1E. Kroll, F.M. Winnik, and R.F. Ziolo, Chem. Mater, 8, 1594 (1996).

Senaratne, U.; Powell, N.; Kroll, E.; Tsoi, G.; Naik, R.; Naik, V.; Vaishnava, P. P.; Wenger, L. E.

2004-03-01

144

Immobilisation of arsenic by iron(II)-oxidizing bacteria  

NASA Astrophysics Data System (ADS)

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.

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

2008-12-01

145

Fossilization of Iron-Oxidizing Bacteria at Hydrothermal Vents: a Useful Biosignature on Mars?  

Microsoft Academic Search

Iron oxidizing bacteria are ubiquitous in marine and terrestrial environments on Earth, where they often display distinctive cell morphologies and are commonly encrusted by minerals, especially bacteriogenic iron oxides and silica. Putative microfossils of iron oxidizing bacteria have been found in jaspers as old as 490Ma and microbial iron oxidation may be an ancient metabolic pathway. In order to investigate

R. J. Leveille; S. Lui

2009-01-01

146

Photoelectrochemical Properties of Plasma Deposited Iron Oxide Thin Films.  

National Technical Information Service (NTIS)

Thin films of iron oxide were produced by the rf glow discharge decomposition of iron pentacarbonyl in the presence of oxygen. Emission spectra showed the presence of oxygen atoms, FeO, Fe(I), CO, Ar and N sub 2 . Stoichiometric Fe sub 2 O sub 3 was noted...

C. S. Blair

1984-01-01

147

On the drying rates of individual iron oxide pellets  

Microsoft Academic Search

After agglomeration, iron oxide pellets are sintered in continuous furnaces to develop the mechanical properties required by iron making plants. In the first zones of the furnace, pellets are dried by the hot recycled gas. The objective of the study is to model their drying kinetics. For that purpose, individual pellets, instrumented for temperature measurement, are dried in a laboratory

T. Tsukerman; C. Duchesne; D. Hodouin

2007-01-01

148

Magnetic Iron Oxide Nanoparticles: Synthesis and Surface Functionalization Strategies  

PubMed Central

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.

2008-01-01

149

Ferric iron reduction by sulfur- and iron-oxidizing bacteria. [Clostridium and Methanobacterium  

Microsoft Academic Search

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

T. D. Brock; J. Gustafson

1976-01-01

150

Acceleration of zinc corrosion in alkaline suspensions containing iron oxides or iron hydroxides  

Microsoft Academic Search

Fast zinc dissolution is of industrial interest in recycling galvanised steel scraps. An acceleration of zinc corrosion in alkaline solutions was observed in the presence of various iron oxides or iron hydroxides. This corrosion was investigated by weight loss, measurements of hydrogen evolution and variation of current in a galvanic cell. The mechanism of this fast zinc corrosion was investigated

V. Alonzo; A. Darchen; D. Hauchard; S. Paofai

2003-01-01

151

Facile synthesis of magnetic iron oxide nanoparticles and their characterization  

NASA Astrophysics Data System (ADS)

Magnetic iron oxide nanoparticles are synthesized by suitable modification of the standard synthetic procedure without use of inert atmosphere and at room temperature. The facile synthesis procedure can be easily scaled up and is of important from industrial point of view for the commercial large scale production of magnetic iron oxide nanoparticles. The synthesized nanoparticles were characterized by thermal, dynamic light scattering, scanning electron microscopy and transmission electron microscopy analyses.

Jadhav, Sushilkumar A.; Patil, Suresh V.

2014-06-01

152

Photoreductive dissolution of colloidal iron oxides in natural waters  

Microsoft Academic Search

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

T. David Waite; Francois M. M. Morel

1984-01-01

153

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

NASA Astrophysics Data System (ADS)

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 FeCl3 within a NaBH4 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/Fe3O4 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/Fe3O4 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/Fe3O4 particles (100-190 emu/g) can be twice as high, and the coercivity (HC) can be tunable from several Oe to several hundred Oe. Hence, the SAR of Fe/Fe3O4 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.

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

2007-03-01

154

In vitro demonstration of anaerobic oxidation of methane coupled to sulphate reduction in sediment from a marine gas hydrate area  

Microsoft Academic Search

Summary Anaerobic oxidation of methane (AOM) and sulphate reduction were examined in sediment samples from a marine gas hydrate area (Hydrate Ridge, NE Pacific). The sediment contained high numbers of microbial consortia consisting of organisms that affi- liate with methanogenic archaea and with sulphate- reducing bacteria. Sediment samples incubated under strictly anoxic conditions in defined mineral medium (salinity as in

Katja Nauhaus; Antje Boetius; Martin Kruger; Friedrich Widdel

2002-01-01

155

Ferrates (iron(VI) and iron(V)): Environmentally friendly oxidants and disinfectants  

Microsoft Academic Search

Iron(VI) and iron(V), known as ferrates, are powerful oxidants and their reactions with pollutants are typically fast with the formation of non-toxic by-products. Oxidations performed by Fe(VI) and Fe(V) show pH dependence; faster rates are observed at lower pH. Fe(VI) shows excellent disinfectant properties and can inactivate a wide variety of microorganisms at low Fe(VI) doses. Fe(VI) also possesses efficient

Virender K. Sharma; Futaba Kazama; Hu Jiangyong; Ajay K. Ray

2005-01-01

156

Photoelectrochemistry at iron oxide electrodes. Final technical report. [Iron oxide electrodes for photoelectrolysis of H/sub 2/O  

SciTech Connect

The object of the research program was to extend the knowledge of semiconductor photoelectrochemistry for the decomposition of water into hydrogen fuel and oxygen. In particular, a study of iron oxide electrodes in various electrolytes was investigated.

Kennedy, J.H.

1984-01-01

157

Highly dispersed iron oxides on mesoporous carbon for selective oxidation of benzyl alcohol with molecular oxygen.  

PubMed

Highly dispersed iron oxide supported catalysts, prepared using HNO3-treated CMK-3 mesoporous carbons as supports, exhibit relatively high catalytic activity in selective oxidation of benzyl alcohol with oxygen. PMID:24409455

Geng, Longlong; Zhang, Xiuyan; Zhang, Wenxiang; Jia, Mingjun; Liu, Gang

2014-03-18

158

Genomic insights into microbial iron oxidation and iron uptake strategies in extremely acidic environments.  

PubMed

This minireview presents recent advances in our understanding of iron oxidation and homeostasis in acidophilic Bacteria and Archaea. These processes influence the flux of metals and nutrients in pristine and man-made acidic environments such as acid mine drainage and industrial bioleaching operations. Acidophiles are also being studied to understand life in extreme conditions and their role in the generation of biomarkers used in the search for evidence of existing or past extra-terrestrial life. Iron oxidation in acidophiles is best understood in the model organism Acidithiobacillus ferrooxidans. However, recent functional genomic analysis of acidophiles is leading to a deeper appreciation of the diversity of acidophilic iron-oxidizing pathways. Although it is too early to paint a detailed picture of the role played by lateral gene transfer in the evolution of iron oxidation, emerging evidence tends to support the view that iron oxidation arose independently more than once in evolution. Acidic environments are generally rich in soluble iron and extreme acidophiles (e.g. the Leptospirillum genus) have considerably fewer iron uptake systems compared with neutrophiles. However, some acidophiles have been shown to grow as high as pH 6 and, in the case of the Acidithiobacillus genus, to have multiple iron uptake systems. This could be an adaption allowing them to respond to different iron concentrations via the use of a multiplicity of different siderophores. Both Leptospirillum spp. and Acidithiobacillus spp. are predicted to synthesize the acid stable citrate siderophore for Fe(III) uptake. In addition, both groups have predicted receptors for siderophores produced by other microorganisms, suggesting that competition for iron occurs influencing the ecophysiology of acidic environments. Little is known about the genetic regulation of iron oxidation and iron uptake in acidophiles, especially how the use of iron as an energy source is balanced with its need to take up iron for metabolism. It is anticipated that integrated and complex regulatory networks sensing different environmental signals, such as the energy source and/or the redox state of the cell as well as the oxygen availability, are involved. PMID:22050575

Bonnefoy, Violaine; Holmes, David S

2012-07-01

159

Characteristics of hollow microtubes consisting of amorphous iron oxide nanoparticles produced by iron oxidizing bacteria, Leptothrix ochracea  

Microsoft Academic Search

Some features of characteristic iron oxide sheaths which the iron oxidizing bacteria Leptothrix ochracea (L. oceracea) formed were studied in order to make clear their morphology microstructure, chemical composition, and crystal structure through scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDX), and X-ray diffraction (XRD). Each sheath was a hollow tube with average outer and inner diameters of 1.1

H. Hashimoto; S. Yokoyama; H. Asaoka; Y. Kusano; Y. Ikeda; M. Seno; J. Takada; T. Fujii; M. Nakanishi; R. Murakami

2007-01-01

160

In situ precipitation: a novel approach for preparation of iron-oxide magnetoliposomes  

PubMed Central

Background Conventional methods of preparing magnetoliposomes are complicated and inefficient. A novel approach for magnetoliposomes preparation was investigated in the study reported here. Methods FeCl3/FeCl2 solutions were hydrated with lipid films to obtain liposome-encapsulated iron ions by ultrasonic dispersion. Non-encapsulated iron ions were removed by dialysis. NH3 · H2O was added to the system to adjust the pH to a critical value. Four different systems were prepared. Each was incubated at a different temperature for a different length of time to facilitate the permeation of NH3 · H2O into the inner phase of the liposomes and the in situ formation of magnetic iron-oxide cores in the liposomes. Single-factor analysis and orthogonal-design experiments were applied to determinate the effects of alkalization pH, temperature, duration, and initial Fe concentration on encapsulation efficiency and drug loading. Results The magnetoliposomes prepared by in situ precipitation had an average particle size of 168±14 nm, zeta potential of ?26.2±1.9 mV and polydispersity index of 0.23±0.06. The iron-oxide cores were confirmed as Fe3O4 by X-ray diffraction and demonstrated a superparamagnetic response. Encapsulation efficiency ranged from 3% to 22%, while drug loading ranged from 0.2 to 1.58 mol Fe/mol lipid. The optimal conditions for in situ precipitation were found to be an alkalization pH of 12, temperature of 60°C, time of 60 minutes, and initial Fe concentration of 100 mM Fe3+ + 50 mM Fe2+. Conclusion In situ precipitation could be a simple and efficient approach for the preparation of iron-oxide magnetoliposomes.

Xia, Shudong; Li, Peng; Chen, Qiang; Armah, Malik; Ying, Xiaoying; Wu, Jian; Lai, Jiangtao

2014-01-01

161

Evaluation of the thermodynamic properties of hydrated metal oxide nanoparticles by INS techniques  

SciTech Connect

In this contribution we will present a detailed methodology for the elucidation of the following aspects of the thermodynamic properties of hydrated metal oxide nanoparticles from high-resolution, low-temperature inelastic neutron scattering (INS) data: (i) the isochoric heat capacity and entropy of the hydration layers both chemi- and physisorbed to the particle surface; (ii) the magnetic contribution to the heat capacity of the nanoparticles. This will include the calculation of the vibrational density of states (VDOS) from the raw INS spectra, and the subsequent extraction of the thermodynamic data from the VDOS. This technique will be described in terms of a worked example namely, cobalt oxide (Co3O4 and CoO). To complement this evaluation of the physical properties of metal oxide nanoparticle systems, we will emphasise the importance of high-resolution, high-energy INS for the determination of the structure and dynamics of the water species, namely molecular (H2O) and dissociated water (OH, hydroxyl), confined to the oxide surfaces. For this component of the chapter we will focus on INS investigations of hydrated isostructural rutile (a-TiO2) and cassiterite (SnO2) nanoparticles. We will complete this discussion of nanoparticle analysis by including an appraisal of the INS instrumentation employed in such studies with particular focus on TOSCA [ISIS, Rutherford Appleton Laboratory (RAL), U.K.] and the newly developed spectrometer SEQUOIA [SNS, Oak Ridge National Laboratory (ORNL), U.S.A].

Spencer, Elinor [Virginia Polytechnic Institute and State University] [Virginia Polytechnic Institute and State University; Ross, Dr. Nancy [Virginia Polytechnic Institute and State University] [Virginia Polytechnic Institute and State University; Parker, Stewart F. [ISIS Facility, Rutherford Appleton Laboratory (ISIS)] [ISIS Facility, Rutherford Appleton Laboratory (ISIS); Kolesnikov, Alexander I [ORNL] [ORNL

2013-01-01

162

Acidic amorphous silica prepared from iron oxide of bacterial origin.  

PubMed

Microporous and mesoporous silica derived from biogenous iron oxide is an attractive catalyst for various organic reactions. Biogenous iron oxide contains structural silicon, and amorphous silica remains after iron oxide is dissolved in concentrated hydrochloric acid. The amorphous silica containing slight amounts of iron (Si/Fe = ?150) is composed of ?6-nm-diameter granular particles. The amorphous silica has a large surface area of 540 m(2)/g with micropores (1.4 nm) and mesopores (<3 nm). By using pyridine vapor as a probe molecule to evaluate the active sites in the amorphous silica, it was found that this material has strong Brønsted and Lewis acid sites. When the catalytic performance of this material was evaluated for reactions including the ring opening of epoxides and Friedel-Crafts-type alkylations, which are known to be catalyzed by acid catalysts, this material showed yields higher than those obtained with common silica materials. PMID:23331569

Hashimoto, Hideki; Itadani, Atsushi; Kudoh, Takayuki; Kuroda, Yasushige; Seno, Masaharu; Kusano, Yoshihiro; Ikeda, Yasunori; Nakanishi, Makoto; Fujii, Tatsuo; Takada, Jun

2013-02-01

163

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

SciTech Connect

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%.

Bystrzejewski, M., E-mail: mibys@chem.uw.edu.pl [Dept of Chemistry, Warsaw University, Pasteura 1, 02-093 Warsaw (Poland)

2011-06-15

164

Iron metabolism, free radicals, and oxidative injury  

Microsoft Academic Search

Iron has the capacity to accept and donate electrons readily. This capability makes it physiologically essential, as a useful component of cytochromes and oxygen-binding molecules. However, iron is also biochemically dangerous; it can damage tissues by catalyzing the conversion of hydrogen peroxide to free-radical ions that attack cellular membranes, protein and DNA. This threat is reduced in the healthy state

J Emerit; C Beaumont; F Trivin

2001-01-01

165

Stabilization and functionalization of iron oxide nanoparticles for biomedical applications  

NASA Astrophysics Data System (ADS)

Superparamagnetic iron oxide nanoparticles (NPs) are used in a rapidly expanding number of research and practical applications in the biomedical field, including magnetic cell labeling separation and tracking, for therapeutic purposes in hyperthermia and drug delivery, and for diagnostic purposes, e.g., as contrast agents for magnetic resonance imaging. These applications require good NP stability at physiological conditions, close control over NP size and controlled surface presentation of functionalities. This review is focused on different aspects of the stability of superparamagnetic iron oxide NPs, from its practical definition to its implementation by molecular design of the dispersant shell around the iron oxide core and further on to its influence on the magnetic properties of the superparamagnetic iron oxide NPs. Special attention is given to the selection of molecular anchors for the dispersant shell, because of their importance to ensure colloidal and functional stability of sterically stabilized superparamagnetic iron oxide NPs. We further detail how dispersants have been optimized to gain close control over iron oxide NP stability, size and functionalities by independently considering the influences of anchors and the attached sterically repulsive polymer brushes. A critical evaluation of different strategies to stabilize and functionalize core-shell superparamagnetic iron oxide NPs as well as a brief introduction to characterization methods to compare those strategies is given.Superparamagnetic iron oxide nanoparticles (NPs) are used in a rapidly expanding number of research and practical applications in the biomedical field, including magnetic cell labeling separation and tracking, for therapeutic purposes in hyperthermia and drug delivery, and for diagnostic purposes, e.g., as contrast agents for magnetic resonance imaging. These applications require good NP stability at physiological conditions, close control over NP size and controlled surface presentation of functionalities. This review is focused on different aspects of the stability of superparamagnetic iron oxide NPs, from its practical definition to its implementation by molecular design of the dispersant shell around the iron oxide core and further on to its influence on the magnetic properties of the superparamagnetic iron oxide NPs. Special attention is given to the selection of molecular anchors for the dispersant shell, because of their importance to ensure colloidal and functional stability of sterically stabilized superparamagnetic iron oxide NPs. We further detail how dispersants have been optimized to gain close control over iron oxide NP stability, size and functionalities by independently considering the influences of anchors and the attached sterically repulsive polymer brushes. A critical evaluation of different strategies to stabilize and functionalize core-shell superparamagnetic iron oxide NPs as well as a brief introduction to characterization methods to compare those strategies is given. This article was submitted as part of a collection of articles on surface nanotechnology for biological applications. Other papers on this topic can be found in issue 2 of vol. 3 (2011). This issue can be found from the Nanoscale homepage [http://www.rsc.org/nanoscale].

Amstad, Esther; Textor, Marcus; Reimhult, Erik

2011-07-01

166

Preparation of iron oxides using ammonium iron citrate precursor: Thin films and nanoparticles  

NASA Astrophysics Data System (ADS)

Ammonium iron citrate (C 6H 8O 7·nFe ·nH 3N) was used as a precursor for preparing both iron-oxide thin films and nanoparticles. Thin films of iron oxides were fabricated on silicon (111) substrate using a successive-ionic-layer-adsorption-and-reaction (SILAR) method and subsequent hydrothermal or furnace annealing. Atomic force microscopy (AFM) images of the iron-oxide films obtained under various annealing conditions show the changes of the micro-scale surface structures and the magnetic properties. Homogenous Fe 3O 4 nanoparticles around 4 nm in diameter were synthesized by hydrothermal reduction method at low temperature and investigated using transmission electron microscopy (TEM).

Park, Sangmoon

2009-09-01

167

Reduction of nitric oxide with ammonia on iron oxide-titanium oxide catalyst  

Microsoft Academic Search

The reduction of NO with NHâ on iron oxide-titanium oxide was studied by using a flow reactor between 250 and 450°C. It was found that NO reacts with NHâ at a 1:1 mole ratio in the presence of excess Oâ and the reaction is completely inhibited by the absence of Oâ. The formation of NâO, if any, was negligible in

Akira Kato; Shimpei Matsuda; Fumito Nakajima; Makoto Imanari; Yoshihisa Watanabe

1981-01-01

168

Synthesis and characterization of iron oxide nanoparticles dispersed in mesoporous aluminum oxide or silicon oxide  

Microsoft Academic Search

Iron oxide nanoparticles dispersed in aluminum (Al) or silicon (Si) oxides were prepared via a polymeric precursor derived\\u000a from the Pechini method. The samples were characterized by thermogravimetric analysis, Fourier-transform infrared spectroscopy,\\u000a X-ray diffraction, N2 adsorption\\/desorption isotherms (Brunauer–Emmett–Teller, BET), Mössbauer spectroscopy, and vibrating sample magnetometry\\u000a (VSM). BET analysis shows that the samples are mesoporous materials and have a high surface

Tiago Pinheiro Braga; Antônio Narcísio Pinheiro; W. T. Herrera; Y. T. Xing; E. Baggio-Saitovitch; Antoninho Valentini

2011-01-01

169

Ab initio study of the uranyl oxide hydrates: a proton transfer mediated by water  

NASA Astrophysics Data System (ADS)

We present a first-principles study of the UO3·n(H2O) uranyl oxide hydrates, namely, schoepite (n = 2.25), metaschoepite (n = 2) and dehydrated metaschoepite (n = 1.75), which appear as the alteration U(VI) products of aqueous corrosion of nuclear fuel. For these compounds, the calculated enthalpy of formation is in good agreement with calorimetry and solubility measurements. We discuss the key electronic state factors behind the phase stability of uranyl oxide hydrates. An unexplored proton-transfer mechanism, which produces the H3O hydronium ions in UO3·nH2O, has been studied using ab initio molecular dynamics simulations at room temperature. For the hydronium ion, a very short lifetime of around 20 fs has been suggested.

Ostanin, S.; Zeller, P.

2007-06-01

170

The Oxidation Of Iron In A Gel Using Consumer Chemicals  

ERIC Educational Resources Information Center

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.

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

2005-01-01

171

Iron and titanium oxides in soil clays and silts  

Microsoft Academic Search

The methods of extraction of free sesquioxides in soils are discussed. Using aluminium foil and ammonium tartrate, the readily soluble sesquioxides are removed from soil profiles and the resultant mechanical analyses are compared. Differences between iron oxide content and titanium oxide content of treated and untreated silt and clay fractions, show that there is more readily soluble material in the

R. J. W. McLaughlin

1954-01-01

172

Magnetic properties of polymer nanocomposites containing iron oxide nanoparticles  

Microsoft Academic Search

The magnetic behavior of polymer nanocomposites containing nanoparticles (?10nm) of oxidized magnetite in a polyvinyl alcohol matrix were investigated by means of Mossbauer transmission and conversion electron spectroscopy and magnetic measurements. The obtained results show that the base concentration of iron oxide nanoparticles within the polymer matrix volume greatly influences the magnetic properties of nanocomposites. The estimated lamellar distribution of

A. A. Novakova; V. Yu. Lanchinskaya; A. V. Volkov; T. S. Gendler; T. Yu. Kiseleva; M. A. Moskvina; S. B. Zezin

2003-01-01

173

Manganese and iron oxidation by fungi isolated from building stone  

Microsoft Academic Search

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

M. A. Torre; G. Gomez-Alarcon

1994-01-01

174

Removal of metal ions from water solutions by iron/cobalt oxide coated keramzite.  

PubMed

A method for coating hydrated iron, cobalt and iron/cobalt oxide on the surface of keramzite sand was developed. The coating parameters (pH, amount of coated metal, molar ratio Co/Fe, temperature of modification and time of treatment) controlling sorption ability of the coated layer were determined. The iron/cobalt coated keramzite thermally activated at 450 degrees C obtained at a molar ratio Co/Fe-0.516 is characterized and use for the removal of metal ions. The effect of contact time, solution pH, sorbate concentration, ionic strength and competing metal concentration on the sorption of copper, lead, zinc and cadmium was studied in batch experiments. The results reveal that the sorption rate of metal ions increases more rapidly in the initial period and reach metastable equilibrium within three hours. The sorption on coated keramzite follows both Langmuir and Freundlich's models. The data on the effect of pH showed that the sorption of all metal ions studied was markedly influenced by the solution pH. According to the concept of surface complexation model the experimental results support the assumption that metal adsorption at oxide coated keramzite sand could be better modeled as an innersphere surface reaction. The modified sorbent has a high selectivity towards copper and lead ions. The coated keramzite sand can be recommended as an efficient adsorbent for advanced water treatment of metal-bearing solutions and industrial wastewaters. PMID:11545353

Stefanova, R Y

2001-01-01

175

Mössbauer effect phase determination in iron oxide-polyaniline nanocomposites  

NASA Astrophysics Data System (ADS)

Mössbauer effect spectroscopy and thermal analysis techniques were applied to characterize polyaniline composites successfully synthesized by embedding Fe oxide nanoparticles (about 10-13 nm) in a polymeric matrix in the presence of dodecyl benzene sulfonic acid and Hel (dopant). Thermal techniques provided quantitative information on iron oxide content and on polyaniline stability and transformations. Mössbauer results indicated that for the whole studied composition range, 3.4 to 100 iron oxide wt.%, composites hold maghemite particles. A preliminary study of the conductivity of the nanocomposites was performed. The largest conductivity was observed for a 8 wt.% maghemite composite where all particles are magnetically unblocked at room temperature within the Mössbauer time window.

Aphesteguy, J. C.; Jacobo, S. E.; Rodríguez Torres, C. E.; Fernández van Raap, M. B.; Sánchez, F. H.

176

Carboxyfullerene prevents iron-induced oxidative stress in rat brain.  

PubMed

Carboxyfullerene, a water-soluble carboxylic acid derivative of a fullerene, was investigated as a protective agent against iron-induced oxidative stress in the nigrostriatal dopaminergic system of anesthetized rats. Intranigral infusion of exclusive carboxyfullerene did not increase lipid peroxidation in substantia nigra or deplete dopamine content in striatum. Infusion of ferrous citrate (iron II) induced degeneration of the nigrostriatal dopaminergic system. An increase in lipid peroxidation in substantia nigra as well as decreases in K+-evoked dopamine overflow and dopamine content in striatum were observed 7 days after the infusion. Co-infusion of carboxyfullerene prevented iron-induced oxidative injury. Furthermore, tyrosine hydroxylase-immunoreactive staining showed that carboxyfullerene inhibited the iron-induced loss of the dopaminergic nerve terminals in striatum. The antioxidative action of carboxyfullerene was verified by in vitro studies. Incubation of brain homogenates increased the formation of the Schiff base fluorescent products of malonaldehyde, an indicator of lipid peroxidation. Both autooxidation (without exogenous iron) and iron-induced elevation of lipid peroxidation of brain homogenates were suppressed by carboxyfullerene in a dose-dependent manner. Our results suggest that intranigral infusion of carboxyfullerene appears to be nontoxic to the nigrostriatal dopaminergic system. Furthermore, the potent antioxidative action of carboxyfullerene protects the nigrostriatal dopaminergic system from iron-induced oxidative injury. PMID:10098871

Lin, A M; Chyi, B Y; Wang, S D; Yu, H H; Kanakamma, P P; Luh, T Y; Chou, C K; Ho, L T

1999-04-01

177

Fibrogenic Potential of Intratracheally Instilled Quartz, Ferric Oxide, Fibrous Glass, and Hydrated Alumina in Hamsters  

Microsoft Academic Search

ABSTRAC~ As a first step in the development of an animal model for determining the role of pulmonary fibrosis in the etiology and pathogenesis of lung cancer, the fibrogenic potential of quartz, quartz and ferric oxide adm'inistered together, fibrous glass, and hydrated alumina were studied by multiple intratracheal instillation in groups of male 1ak:LVG Syrian golden hamsters. Dose-related decreases in

ROGER A. RENNE; SANDRA R. ELDRIDGE; TRENT R. LEWIS; DONALD L. STEVENS

1985-01-01

178

A room temperature etching route to tungsten oxide hydrate nanoplates with expanded surface area  

Microsoft Academic Search

Tungsten oxide hydrate nanoplates with expanded surface area have been synthesized through the acid treatment of tungstate?aluminum keggin nanocomposite. According to powder X-ray diffraction and W LIII-edge X-ray absorption spectroscopic analyses, X-ray amorphous nanocomposite is changed into crystalline WO3·2H2O upon the acidic etching of alumina component. Nitrogen adsorption?desorption isotherm and field emission-scanning electron microscopy measurements clearly demonstrated that the surface

Ah Reum Han; Seong-Ju Hwang; Hyun Jung; Jin-Ho Choy

2008-01-01

179

Biogeochemistry of Iron Oxidation in a Circumneutral Freshwater Habitat  

NASA Astrophysics Data System (ADS)

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.

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

2007-12-01

180

Sol–gel processed iron oxide–silica nanocomposite films as room-temperature humidity sensors  

Microsoft Academic Search

Iron oxide–silica nanocomposite films have been fabricated using sol–gel process and spin coating technique. Iron oxide and silica were segregated. As Si content in the films increase, the films were more compact. The iron oxide films calcined at 400°C were hematite (?-Fe2O3), but in the presence of silica, iron oxide is composed of hematite and magnetite. The response of iron

R. Tongpool; S. Jindasuwan

2005-01-01

181

Chapter 1 Surface Structure and Reactivity of Iron Oxide-Water Interfaces.  

SciTech Connect

The surface structure and composition of the three distinct iron-(hydr)oxide systems, goethite (1 0 0), hematite (1{bar 1}02), and magnetite (1 1 1) were determined under hydrated conditions at room temperature using crystal truncation rod (CTR) analysis. The prediction of surface protonation states and the overall chemical plausibility of the experimental surface models are performed using a bond-valence (BV) analysis. Further analysis of the surface energetics is carried out using density functional theory (DFT). The analysis of three common iron-(hydr)oxide surface systems reveals the differences in interface structure and distribution of hydroxyl groups at substrate-water interfaces. The goethite (1 0 0) interface structure is determined to have a relaxed double hydroxyl termination with the presence of two semi-ordered water layers that expose a surface with A-type (Fe-OH{sub 2}) and B-type (Fe{sub 2}-OH) hydroxyl groups. The hydrated hematite (1{bar 1}02) interface structure has vacancies in the near surface metal sites, resulting in three types of surface functional groups: A type, B type, and C type (Fe{sub 3}-O). The interface structure of magnetite (1 1 1) shows two chemically nonequivalent oxygen surface terminations in the surface ratio of 70 O{sub 4}-Fe{sub oh}-O{sub 4}-Fe{sub td1-oh-td2}:30 O{sub 4}-Fe{sub td1-oh-td2}-O{sub 4}-Fe{sub oh} suggesting that the octahedral irons are the principal irons involved at the environmental interfaces. In the above three systems, there also is evidence for multiple domains with fractional ordered unit cell steps determined by atomic force microscopy (AFM). Results obtained for the structure of the iron-(hydr)oxide-water interfaces from the CTR and DFT analyses are different from stoichiometric termination of the bulk structure or hydroxylation of the ultra high vacuum (UHV) determined surface structures.

Ghose, S.K.; Petitto, S.C.; Tanwar, K.S.; Lo, C.S.; Eng, P.J.; Chaka, A.M.; Trainor, T.P. (Univ Alaska Fairbanks); (UofC)

2008-04-29

182

Size and shape controllable synthesis of monodisperse iron oxide nanoparticles by thermal decomposition of iron oleate complex  

Microsoft Academic Search

We have demonstrated the effects of reaction temperature, reaction concentration, surfactant concentration, refluxing time, seed-mediated growth, and heating rate on the size and morphology of iron oxide nanoparticles synthesized by thermal decomposition of iron oleate complex through “heating-up” process. By precisely controlling the reaction parameters, monodisperse iron oxide nanoparticles with the sizes ranging from 7 to 35 nm and controllable

Zhongping Chen

2012-01-01

183

Clathrate Hydrates of Oxidants in the Ice Shell of Europa  

NASA Astrophysics Data System (ADS)

Europa's icy surface is radiolytically modified by high-energy electrons and ions, and photolytically modified by solar ultraviolet photons. Observations from the Galileo Near Infrared Mapping Spectrometer, ground-based telescopes, the International Ultraviolet Explorer, and the Hubble Space Telescope, along with laboratory experiment results, indicate that the production of oxidants, such as H2O2, O2, CO2, and SO2, is a consequence of the surface radiolytic chemistry. Once created, some of the products may be entrained deeper into the ice shell through impact gardening or other resurfacing processes. The temperature and pressure environments of regions within the europan hydrosphere are expected to permit the formation of mixed clathrate compounds. The formation of carbon dioxide and sulfur dioxide clathrates has been examined in some detail. Here we add to this analysis by considering oxidants produced radiolytically on the surface of Europa. Our results indicate that the bulk ice shell could have a ~1.7-7.6% by number contamination of oxidants resulting from radiolysis at the surface. Oxidant-hosting clathrates would consequently make up ~12-53% of the ice shell by number relative to ice, if oxidants were entrained throughout. We examine, in brief, the consequences of such contamination on bulk ice shell thickness and find that clathrate formation could lead to substantially thinner ice shells on Europa than otherwise expected. Finally, we propose that double occupancy of clathrate cages by O2 molecules could serve as an explanation for the observation of condensed-phase O2 on Europa. Clathrate-sealed, gas-filled bubbles in the near surface ice could also provide an effective trapping mechanism, though they cannot explain the 5771 Å (O2)2 absorption.

Hand, Devin P.; Chyba, Christopher F.; Carlson, Robert W.; Cooper, John F.

2006-06-01

184

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

NASA Astrophysics Data System (ADS)

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.

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

2010-03-01

185

Iron(VI): Hypothetical Candidate for the Martian Oxidant  

Microsoft Academic Search

As a result of the Viking missions of the early 1970s, the presence of a strong oxidant in martian soil was suggested. Here we present a hypothesis, testable by near-term missions, that iron(VI) is a likely contributor to the martian oxidative pool. In this context, ferrate(VI) salts, with FeO42? anion, were studied for their spectral and oxidative properties. Ferrate(VI) has

A. I. Tsapin; M. G. Goldfeld; G. D. McDonald; K. H. Nealson; B. Moskovitz; P. Solheid; K. M. Kemner; S. D. Kelly; K. A. Orlandini

2000-01-01

186

Oxidation of marcasite and pyrite by iron-oxidizing bacteria and archaea  

Microsoft Academic Search

This study evaluated the oxidation of research-grade marcasite and pyrite in shake flask experiments using iron-oxidizing bacteria and archaea at 22, 45, and 65 °C. Dissolved iron concentration and pH were monitored at intervals. The results showed that marcasite was more reactive than pyrite to both microbiological and chemical oxidation. These results are consistent with established structural and thermodynamic differences between

Hongmei Wang; Jerry M. Bigham; Olli H. Tuovinen

2007-01-01

187

Bacterial oxidation of ferrous iron at low temperatures.  

PubMed

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

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

2007-08-15

188

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

PubMed Central

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 why SPIONs can be synthesised and examines their characteristics and limitations in the context of MR imaging.

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

2010-01-01

189

Size-dependent properties of magnetic iron oxide nanocrystals  

Microsoft Academic Search

The fine control of iron oxide nanocrystal sizes within the nanometre scale (diameters range from 2.5 to 14 nm) allows us to investigate accurately the size-dependence of their structural and magnetic properties. A study of the growth conditions of these nanocrystals obtained by thermal decomposition of an iron oleate precursor in high-boiling point solvents has been carried out. Both the

A. Demortière; P. Panissod; B. P. Pichon; G. Pourroy; D. Guillon; B. Donnio; S. Bégin-Colin

2011-01-01

190

Identification of iron oxide and hydroxide in soil clays  

Microsoft Academic Search

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 (alpha-Fe2O3, hematite) and iron oxyhydroxide (alpha-FeOOH, goethite) in the form of fine particles\\/Al-substituted. All samples exhibited strong superparamagnetism, characteristic of the fine size

S. P. Taneja; D. Raj

1993-01-01

191

Inorganic Production of Membranes Together with Iron Carbide via Oxidization of Iron in the Water that Includes Carbon Dioxide Plentifully  

NASA Astrophysics Data System (ADS)

Experimental results are reported. The data indicate iron carbide possessing function to assist the Fischer-Tropsch reaction is made from deoxidgenation of carbon dioxide dissolved in water via oxidation of iron atoms.

Karasawa, S. K.

2010-04-01

192

Modeling of iron oxide deposition by reactive ion beam sputtering  

SciTech Connect

An analytic model of deposition is applied on reactive ion beam sputtering to optimize the properties of iron oxide thin films. This model will be able to predict deposition rate and phase contents. Among its hypotheses, we assume oxygen adsorption at the surface of the target to explain variations of deposition rate for oxygen flow. This hypothesis is validated by chemical analyses on iron targets. An ellipsoidal distribution of probability is introduced to model sputtered matter distribution from iron target and to calculate sputtering yield. Comparison between experimental and calculated deposition rates validates previously assumed hypotheses.

Puech, Laurent [CEA, LETI, MINATEC, 38054 Grenoble (France); Institut Carnot, CIRIMAT, UMR CNRS 5085, 31062 Toulouse (France); CEA, LITEN, 38054 Grenoble (France); Dubarry, Christophe; Ravel, Guillaume; Vito, Eric de [CEA, LITEN, 38054 Grenoble (France)

2010-03-15

193

Microbial reduction of crystalline iron(III) oxides: Influence of oxide surface area and potential for cell growth  

Microsoft Academic Search

Quantitative aspects of microbial crystalline iron(III) oxide reduction were examined using a dissimilatory iron(III) oxide-reducing bacterium (Shewanella alga strain BrY). The initial rate and long-term extent of reduction of a range of synthetic iron(III) oxides were linearly correlated with oxide surface area. Oxide reduction rates reached an asymptote at cell concentrations in excess of =1 x 10⁹\\/m² of oxide surface.

Eric E. Roden; John M. Zachara

1996-01-01

194

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

NASA Astrophysics Data System (ADS)

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.

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

2009-03-01

195

Annealing effects on 5 nm iron oxide nanoparticles.  

PubMed

Morphological, structural and magnetic properties of 4.8 nm iron oxide nanoparticles have been investigated after annealing under inert atmosphere at different temperatures. The as-prepared iron oxide nanoparticles have been synthesized by chemical route from high temperature reaction of Fe(acac)3 solution in presence of oleic acid and oleylamine surfactant. Annealing the particles at low temperatures (Tann = 573 K) produces an increment of the mean size from 4.8 nm to 6.0 nm, preserving the same morphology. The coercive field of the annealed sample has a small increasing with respect to the as-prepared sample in agreement with the mean particle volume change. Annealing at higher temperature (Tann = 823 K) leads to a bimodal size distribution of the iron oxide nanoparticles with 6.0 nm and 17 nm mean sizes respectively, where the bigger particles dominate the observed magnetic properties. PMID:18019166

Vargas, J M; Lima, E; Socolovsky, L M; Knobel, M; Zanchet, D; Zysler, R D

2007-09-01

196

Multimodal iron oxide nanoparticles for hybrid biomedical imaging.  

PubMed

Iron oxide core nanoparticles are attractive imaging agents because their material properties allow the tuning of pharmacokinetics as well as the attachment of multiple moieties to their surface. In addition to affinity ligands, these include fluorochromes and radioisotopes for detection with optical and nuclear imaging. As the iron oxide core can be detected by MRI, options for combining imaging modalities are manifold. Already, preclinical imaging strategies have combined noninvasive imaging with higher resolution techniques, such as intravital microscopy, to gain unprecedented insight into steady-state biology and disease. Going forward, hybrid iron oxide nanoparticles will help to merge modalities, creating a synergy that will enable imaging in basic research and, potentially, also in the clinic. PMID:23065771

Heidt, Timo; Nahrendorf, Matthias

2013-07-01

197

Magnetic behaviour of iron nanoparticles passivated by oxidation  

NASA Astrophysics Data System (ADS)

This study is to understand the effect of oxidation, especially magnetically, on iron nanoparticles. According to generation of the oxidated iron nanoparticles, mechanical alloying technique was used and nanosized magnetite (Fe3O4), maghemite (-Fe2O3) and hematite (-Fe2O3) particles were obtained as the resultant samples. The reactance to the thermal treatment was determined by differential thermal analysis and thermogravimetric (DTA-TG) measurements. X-ray powder diffractions (XRD) helped to exhibit the structure of the sample by ICDD cards and to determine the size of nanoparticles by using the Scherrer formula. On the other hand, VSM (vibrating sample magnetometer) measurements were determined to understand the magnetic behaviour. Through the transformation of Fe3O4 to other iron-oxides, two exothermic peaks were observed at around 169.11 °C and 562.61 °C by DTA analysis. Beside of this, the experimental results demonstrate the effects of mechanical milling parameters, atmosphere and lubricant, to the structure and to the size of the resultant particles and the change of magnetic behavior of the iron-oxide and iron nanoparticles when they approach to superparamagnetic region, especially in single domain region.

Mutlu Can, Musa; Özcan, Adan; Frat, Tezer

2006-05-01

198

Arsenate adsorption onto iron oxide amended rice husk char.  

PubMed

In this study, rice husks were charred at 550°C in a partially sealed ceramic vessel for 30minutes to create a high specific surface area (SSA) rice husk char (RHC). The RHC was then amended with iron oxides using dissolved ferric nitrate, Fe(NO3)3 ? 9H2O, to provide a surface chemistry conducive to arsenic adsorption. The 550°C iron oxide amended rice husk char's (550 IOA-RHC's) SSA was nearly 2.5 orders of magnitude higher and the arsenate adsorptive level was nearly 2 orders of magnitude higher than those reported for iron oxide amended sand, thus indicating a positive relationship between post-amendment SSA and arsenate adsorptive levels. Rice husks were then charred at temperatures ranging from 450°C to 1050°C to create an even higher SSA material, which might further increase arsenate adsorptive levels. The 950°C RHC was chosen for amendment due to its high SSA and feasibility of being produced in the field. Once amended, the 950°C iron oxide amended rice husk char (950 IOA-RHC) improved the arsenate adsorption capacity by thus confirming a positive relationship, though not a linear relationship, between post-amendment SSA and arsenic adsorptive capacity. Further study demonstrated that post-amendment mesoporous volume and mesoporous surface area appear to be better indicators of arsenic adsorptive capacity than SSA or iron content. PMID:24529452

Cope, Christopher O; Webster, Damon S; Sabatini, David A

2014-08-01

199

The oxidation of iron-aluminum alloys  

Microsoft Academic Search

This paper briefly summarizes studies related to the oxidation of Fe-Al alloys. Emphasis is placed on oxide phase composition, morphology, and the development of protective a-Al2O3 scales on oxidation-resistant Fe-Al alloys both with and without ternary additions.

R. Prescott; M. J. Graham

1992-01-01

200

Iron overload inhibits osteoblast biological activity through oxidative stress.  

PubMed

Iron overload has recently been connected with bone mineral density in osteoporosis. However, to date, the effect of iron overload on osteoblasts remains poorly understood. The purpose of this study is to examine osteoblast biological activity under iron overload. The osteoblast cells (hFOB1.19) were cultured in a medium supplemented with different concentrations (50, 100, and 200 ?M) of ferric ammonium citrate as a donor of ferric ion. Intracellular iron was measured with a confocal laser scanning microscope. Reactive oxygen species (ROS) were detected by 2,7-dichlorofluorescin diacetate fluorophotometry. Osteoblast biological activities were evaluated by measuring the activity of alkaline phosphatase (ALP) and mineralization function. Results indicated that iron overload could consequently increase intracellular iron concentration and intracellular ROS levels in a concentration-dependent manner. Additionally, ALP activity was suppressed, and a decline in the number of mineralized nodules was observed in in vitro cultured osteoblast cells. According to these results, it seems that iron overload probably inhibits osteoblast function through higher oxidative stress following increased intracellular iron concentrations. PMID:23334864

He, Yin-Feng; Ma, Yong; Gao, Chao; Zhao, Guo-Yang; Zhang, Lin-Lin; Li, Guang-Fei; Pan, Yun-Zhi; Li, Kai; Xu, You-Jia

2013-05-01

201

Photocatalytic Oxidation of Isoprene on Hydrated Atmospheric Mineral Dusts  

NASA Astrophysics Data System (ADS)

Mineral dust aerosols, an important fraction in the tropospheric aerosol budget, contain transition metal-based semiconductor particles that absorb light and may support diverse chemical transformations. Dust aerosol is primary, mostly originates from deserts, but includes fly ash emitted by power plants, and can be carried over long distances. We propose that such semiconductor particles may produce secondary organic aerosol (SOA) via surface-activated photochemical processes in aqueous media. Isoprene, the most abundant anthropogenic VOC is deemed to be incorporated into SOA by various mechanisms that remain to be fully characterized. We suggest that condensed-phase chemistry, in addition to gas-phase transformations, plays an important role in SOA formation. Isoprene is only slightly soluble in water, but it would react at diffusionally-controlled rates with photochemically generated OH-radicals in aqueous phase to produce more complex, polar compounds via oxidation and polymerization processes. We have found that the similar products are formed in the photolysis of aqueous hydrogen peroxide solutions or titanium dioxide suspensions in the presence of dissolved isoprene, as revealed by HPLC analysis with online high-resolution positive ion electrospray ionization mass spectrometric detection, and 1H and 13C nuclear magnetic resonance spectrometry. In contrast, hematite suspensions display negligible photocatalytic activity toward isoprene oxidation. These results suggest that atmospheric heterogeneous semiconductor photocatalysis of isoprene may play a significant role in global secondary organic aerosol formation under overly dusty conditions. Full product characterization is underway that aims at identifying species that may have adverse health/respiratory effects.

Hoffmann, M. R.; Kameel, F. R.; Colussi, A. J.

2011-12-01

202

Iron oxide modified diamond blends containing ultradispersed diamond.  

PubMed

Iron oxide modified diamond blends containing different amounts of ultradispersed diamond were prepared and characterized by nitrogen physisorption, X-ray diffraction, temperature programmed reduction, Mössbauer and IR spectroscopy. The catalytic behavior of these composite materials in methanol decomposition to hydrogen, carbon monoxide, and methane has been also studied. The initial state and phase transformations of the supported highly dispersed iron oxide particles in various pretreatment media, as well as their reductive and catalytic properties, strongly depend on the ultradispersed diamond content in the diamond blends. PMID:16616929

Tsoncheva, Tanya; Dimitrov, Momtchil; Ivanova, Ljubomira; Paneva, Daniela; Mitev, Dimitar; Tsintsarski, Boiko; Mitov, Ivan; Stavrev, Stavri; Minchev, Christo

2006-08-01

203

Multifunctional Iron Oxide Nanoparticles for Diagnostics, Therapy and Macromolecule Delivery  

PubMed Central

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.

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

2013-01-01

204

Multifunctional iron oxide nanoparticles for diagnostics, therapy and macromolecule delivery.  

PubMed

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

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

2013-01-01

205

Multifunctional superparamagnetic iron oxide nanoparticles: promising tools in cancer theranostics.  

PubMed

Iron-oxide nanoparticles of small dimensions that have superparamagnetic properties show immense potential to revolutionize the future of cancer theranostics, the combinatorial diagnosis and therapeutic approach towards cancer. Superparamagnetic iron-oxide nanoparticles (SPIONs) have unique magnetic properties, due to which they show excellent tumor-targeting efficiency, and this paves the way for effective personalized cancer treatment. The aim of this review is to focus on the ability of SPIONs to perform multiple roles in the field of cancer biology, such as in diagnosis, monitoring, targeting and therapy. Also, other topics are discussed, including the synthesis of SPIONs, the challenges and recent advances. PMID:23664890

Santhosh, Poornima Budime; Ulrih, Nataša Poklar

2013-08-01

206

Core-shell iron-iron oxide nanoparticles synthesized by laser-induced pyrolysis.  

PubMed

Passivated iron nanoparticles (10-30 nm) have been synthesized by laser pyrolysis of a mixture of iron pentacarbonyl and ethylene vapors followed by controlled oxidation. The nanoparticles show a well-constructed iron-iron oxide core-shell structure, in which the thickness and nature (structure similar to maghemite, gamma-Fe2O3) of the shell is found to be independent of the initial conditions. On the other hand, the composition of the core is found to change with the particle size from the alpha-Fe structure to a highly disordered Fe phase (probably containing C atoms in its structure). The dependence of the magnetic properties on the particle size, iron oxide fraction, and temperature was also investigated. In the case of smaller particles, the magnetic data indicate the existence at low temperature of a large exchange anisotropy field, the magnitude of which increases with decreasing temperature in correspondence with the freezing of magnetic moments in the oxide shell. PMID:17193009

Bomatí-Miguel, Oscar; Tartaj, Pedro; Morales, Maria P; Bonville, Pierre; Golla-Schindler, Ute; Zhao, Xinqing Q; Veintemillas-Verdaguer, Sabino

2006-12-01

207

Reactivity of an iron-oxygen oxidant generated upon oxidative decarboxylation of biomimetic iron(II) ?-hydroxy acid complexes.  

PubMed

Three biomimetic iron(II) ?-hydroxy acid complexes, [(Tp(Ph2))Fe(II)(mandelate)(H2O)] (1), [(Tp(Ph2))Fe(II)(benzilate)] (2), and [(Tp(Ph2))Fe(II)(HMP)] (3), together with two iron(II) ?-methoxy acid complexes, [(Tp(Ph2))Fe(II)(MPA)] (4) and [(Tp(Ph2))Fe(II)(MMP)] (5) (where HMP = 2-hydroxy-2-methylpropanoate, MPA = 2-methoxy-2-phenylacetate, and MMP = 2-methoxy-2-methylpropanoate), of a facial tridentate ligand Tp(Ph2) [where Tp(Ph2) = hydrotris(3,5-diphenylpyrazole-1-yl)borate] were isolated and characterized to study the mechanism of dioxygen activation at the iron(II) centers. Single-crystal X-ray structural analyses of 1, 2, and 5 were performed to assess the binding mode of an ?-hydroxy/methoxy acid anion to the iron(II) center. While the iron(II) ?-methoxy acid complexes are unreactive toward dioxygen, the iron(II) ?-hydroxy acid complexes undergo oxidative decarboxylation, implying the importance of the hydroxyl group in the activation of dioxygen. In the reaction with dioxygen, the iron(II) ?-hydroxy acid complexes form iron(III) phenolate complexes of a modified ligand (Tp(Ph2)*), where the ortho position of one of the phenyl rings of Tp(Ph2) gets hydroxylated. The iron(II) mandelate complex (1), upon decarboxylation of mandelate, affords a mixture of benzaldehyde (67%), benzoic acid (20%), and benzyl alcohol (10%). On the other hand, complexes 2 and 3 react with dioxygen to form benzophenone and acetone, respectively. The intramolecular ligand hydroxylation gets inhibited in the presence of external intercepting agents. Reactions of 1 and 2 with dioxygen in the presence of an excess amount of alkenes result in the formation of the corresponding cis-diols in good yield. The incorporation of both oxygen atoms of dioxygen into the diol products is confirmed by (18)O-labeling studies. On the basis of reactivity and mechanistic studies, the generation of a nucleophilic iron-oxygen intermediate upon decarboxylation of the coordinated ?-hydroxy acids is proposed as the active oxidant. The novel iron-oxygen intermediate oxidizes various substrates like sulfide, fluorene, toluene, ethylbenzene, and benzaldehyde. The oxidant oxidizes benzaldehyde to benzoic acid and also participates in the Cannizzaro reaction. PMID:24627956

Paria, Sayantan; Chatterjee, Sayanti; Paine, Tapan Kanti

2014-03-17

208

A simple model for iron oxide biomineralization - synchrotron X-ray scattering analysis of iron oxide precipitated in the presence of amino acids  

Microsoft Academic Search

Iron oxides are very common materials that have a large spectrum of applications both in industry, and in biological systems. In living systems, they can be used as compass, teeth hardener, and iron sink. Some proteins and peptides are used by living organisms as tools to template the synthesis of spatially controlled and polymorph specific iron oxides. We study a

Alexandre MANTION; Andreas TAUBERT

2006-01-01

209

Gas-phase uranyl, neptunyl, and plutonyl: hydration and oxidation studied by experiment and theory.  

PubMed

The following monopositive actinyl ions were produced by electrospray ionization of aqueous solutions of An(VI)O(2)(ClO(4))(2) (An = U, Np, Pu): U(V)O(2)(+), Np(V)O(2)(+), Pu(V)O(2)(+), U(VI)O(2)(OH)(+), and Pu(VI)O(2)(OH)(+); abundances of the actinyl ions reflect the relative stabilities of the An(VI) and An(V) oxidation states. Gas-phase reactions with water in an ion trap revealed that water addition terminates at AnO(2)(+)·(H(2)O)(4) (An = U, Np, Pu) and AnO(2)(OH)(+)·(H(2)O)(3) (An = U, Pu), each with four equatorial ligands. These terminal hydrates evidently correspond to the maximum inner-sphere water coordination in the gas phase, as substantiated by density functional theory (DFT) computations of the hydrate structures and energetics. Measured hydration rates for the AnO(2)(OH)(+) were substantially faster than for the AnO(2)(+), reflecting additional vibrational degrees of freedom in the hydroxide ions for stabilization of hot adducts. Dioxygen addition resulted in UO(2)(+)(O(2))(H(2)O)(n) (n = 2, 3), whereas O(2) addition was not observed for NpO(2)(+) or PuO(2)(+) hydrates. DFT suggests that two-electron three-centered bonds form between UO(2)(+) and O(2), but not between NpO(2)(+) and O(2). As formation of the UO(2)(+)-O(2) bonds formally corresponds to the oxidation of U(V) to U(VI), the absence of this bonding with NpO(2)(+) can be considered a manifestation of the lower relative stability of Np(VI). PMID:22656318

Rios, Daniel; Michelini, Maria C; Lucena, Ana F; Marçalo, Joaquim; Bray, Travis H; Gibson, John K

2012-06-18

210

The interplay of catechol ligands with nanoparticulate iron oxides.  

PubMed

The unique properties exhibited by nanoscale materials, coupled with the multitude of chemical surface derivatisation possibilities, enable the rational design of multifunctional nanoscopic devices. Such functional devices offer exciting new opportunities in medical research and much effort is currently invested in the area of "nanomedicine", including: multimodal imaging diagnostic tools, platforms for drug delivery and vectorisation, polyvalent, multicomponent vaccines, and composite devices for "theranostics". Here we will review the surface derivatisation of nanoparticulate oxides of iron and iron@iron-oxide core-shells. They are attractive candidates for MRI-active therapeutic platforms, being potentially less toxic than lanthanide-based materials, and amenable to functionalisation with ligands. However successful grafting of groups onto the surface of iron-based nanoparticles, thus adding functionality whilst preserving their inherent properties, is one of the most difficult challenges for creating truly useful nanodevices from them. Functionalised catechol-derived ligands have enjoyed success as agents for the masking of superparamagnetic iron-oxide particles, often so as to render them biocompatible with medium to long-term colloidal stability in the complex chemical environments of biological milieux. In this perspective, the opportunities and limitations of functionalising the surfaces of iron-oxide nanoparticles, using coatings containing a catechol-derived anchor, are analysed and discussed, including recent advances using dopamine-terminated stabilising ligands. If light-driven ligand to metal charge transfer (LMCT) processes, and pH-dependent ligand desorption, leading to nanoparticle degradation under physiologically relevant conditions can be suppressed, colloidal stability of samples can be maintained and toxicity ascribed to degradation products avoided. Modulation of the redox behaviour of iron catecholate systems through the introduction of an electron-withdrawing substituent to the aromatic ?-system of the catechol is a promising approach towards achieving these goals. PMID:22241454

Yuen, Alexander K L; Hutton, Georgina A; Masters, Anthony F; Maschmeyer, Thomas

2012-03-01

211

Laboratory-prepared iron oxide coatings on sands: Submicron-scale small-strain stiffness  

Microsoft Academic Search

Chemical weathering of iron-bearing rock minerals results in the formation of iron oxides, which can chemically adsorb onto soil surfaces, and\\/or absorb into their molecular structure. The objective of this paper is to use laboratory-prepared, iron oxide-coated sand to study the role of iron oxide coatings on the small-strain stiffness of coarse-grained soil. Ottawa sands were geochemically coated with iron

J. M. Larrahondo; H. Choo; S. E. Burns

2011-01-01

212

Growth and process conditions of aligned and patternable films of iron(III) oxide nanowires by thermal oxidation of iron.  

PubMed

A simple, catalyst-free growth method for vertically aligned, highly crystalline iron oxide (?-Fe(2)O(3)) wires and needles is reported. Wires are grown by the thermal oxidation of iron foils. Growth properties are studied as a function of temperature, growth time and oxygen partial pressure. The size, morphology and density of the nanostructures can be controlled by varying growth temperature and time. Oxygen partial pressure shows no effect on the morphology of resulting nanostructures, although the oxide thickness increases with oxygen partial pressure. Additionally, by using sputtered iron films, the possibility of growth and patterning on a range of different substrates is demonstrated. Growth conditions can be adapted to less tolerant substrates by using lower temperatures and longer growth time. The results provide some insight into the mechanism of growth. PMID:21832785

Hiralal, P; Unalan, H E; Wijayantha, K G U; Kursumovic, A; Jefferson, D; Macmanus-Driscoll, J L; Amaratunga, G A J

2008-11-12

213

Growth Kinetics of Attached Iron-Oxidizing Bacteria  

PubMed Central

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 (?max), 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.

Wichlacz, Paul L.; Unz, Richard F.

1985-01-01

214

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...

215

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...

216

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

PubMed

Abstract 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

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

2014-05-01

217

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

Microsoft Academic Search

Samples of one-(Fe) and two-component (Fe-Pd and Fe-Pt) catalysts were prepared by incipient wetness impregnation of four\\u000a different supports: TiO2 (anatase), ?-Al2O3, activated carbon, and diatomite. The chosen synthesis conditions resulted in the formation of nanosized supported phases—iron\\u000a oxide (in the one-component samples), or iron oxide-noble metal (in the two-component ones). Different agglomeration degrees\\u000a of these phases were obtained as

Z. P. Cherkezova-Zheleva; M. G. Shopska; J. B. Krsti?; D. M. Jovanovi?; I. G. Mitov; G. B. Kadinov

2007-01-01

218

Mössbauer spectroscopic characterization of ultrafine iron oxide and oxyhydroxide prepared by oxidative hydrolysis  

NASA Astrophysics Data System (ADS)

The formation of small iron oxyhydroxide particles in the course of oxidative hydrolysis of Fe(II) sulphate has been investigated by Mössbauer spectroscopy. The influence of the basic temperature as basic parameter on the properties of the iron oxyhydroxide produced has been established. The results obtained are explained by a scheme of a process, including chemical and physical stages.

Mitov, I.; Tabakova, T.; Andreeva, D.; Tomov, T.

1991-03-01

219

The isolation and use of iron-oxidizing, moderately thermophilic acidophiles from the Collie coal mine for the generation of ferric iron leaching solution  

Microsoft Academic Search

Moderately thermophilic, iron-oxidizing acidophiles were enriched from coal collected from an open-cut mine in Collie, Western Australia. Iron-oxidizers were enriched in fluidized-bed reactors (FBR) at 60 °C and 70 °C; and iron-oxidation rates were determined. Ferrous iron oxidation by the microbiota in the original coal material was inhibited above 63 §C. In addition to four iron-oxidizers, closely related to Sulfobacillus

P. H.-M. Kinnunen; W. J. Robertson; J. J. Plumb; J. A. E. Gibson; P. D. Nichols; P. D. Franzmann; J. A. Puhakka

2003-01-01

220

Magnetic properties of polymer nanocomposites containing iron oxide nanoparticles  

NASA Astrophysics Data System (ADS)

The magnetic behavior of polymer nanocomposites containing nanoparticles (˜10 nm) of oxidized magnetite in a polyvinyl alcohol matrix were investigated by means of Mossbauer transmission and conversion electron spectroscopy and magnetic measurements. The obtained results show that the base concentration of iron oxide nanoparticles within the polymer matrix volume greatly influences the magnetic properties of nanocomposites. The estimated lamellar distribution of superparamagnetic Fe 3O 4 islands actuates the magnetic anisotropy formation in the investigated films.

Novakova, A. A.; Lanchinskaya, V. Yu.; Volkov, A. V.; Gendler, T. S.; Kiseleva, T. Yu.; Moskvina, M. A.; Zezin, S. B.

2003-03-01

221

Iron Oxide-Gold Core-Shell Nanoparticles and Thin-Film Assembly  

Microsoft Academic Search

This paper reports findings of an investigation of the synthesis of monolayer-capped iron oxide and core (iron oxide)shell (gold) nanocomposite and their assembly towards thin film materials. Pre-synthesized and size-defined iron oxide nanoparticles were used as seeding materials for the reduction of gold precursors, which was shown to be effective for coating the iron oxide cores with gold shells (Fe

Lingyan Wang; Jin Luo; Mathew M. Maye; Quan Fan; Rendeng Qiang; Mark H. Engelhard; Chongmin Wang; Yuehe Lin; Chuan-Jian Zhong

2005-01-01

222

Behavior of iron aluminides in oxidizing and sulfidizing environments  

SciTech Connect

To date, use of iron aluminides based on Fe/sub 3/Al (less than or equal to30 at. % Al) or FeAl (30--50 at. % Al) for structural applications has been limited by their low ductility and poor fracture toughness at room temperature and inadequate strength above 600/degree/C. However, in recent years, a renewed effort has been devoted to the development of ductile iron aluminides with increased strength, particularly in view of their good potential for use in hostile environments. While it is expected that such aluminides will be able to form oxide scales for corrosion protection in oxidizing high temperature environments, resistance to degradation in oxidizing salt or oxidizing/sulfidizing gas environments has not been adequately addressed as a function of compositional and microstructural changes. This paper reviews and extends results for iron aluminides exposed to an oxidizing/sulfidizing gas and presents the first data for corrosion of this class of materials by an aggressive oxidizing molten nitrate salt of 48.5NaNO/sub 3/--50.5KNO/sub 3/--1Na/sub 2/O/sub 2/. 14 refs., 11 figs.

Tortorelli, P.F.; DeVan, J.H.; DiStefano, J.R.

1989-01-01

223

Size effect of Mössbauer parameters in iron oxide nanoparticles  

NASA Astrophysics Data System (ADS)

The size dependence of Mössbauer parameters for iron oxide nanoparticles in the 10-25 nm range was investigated. It was shown that the isomer shift and hyperfine field parameters decrease with the nanoparticle size. Only at 25 nm the presence of magnetite was detected.

Gabbasov, R. R.; Cherepanov, V. M.; Chuev, M. A.; Polikarpov, M. A.; Panchenko, V. Y.

2014-04-01

224

Biological Crystallization of Self-Aligned Iron Oxide Nanoparticles  

Microsoft Academic Search

Crystal growth and magnetic behavior of iron oxide nanoparticles assembled with biomolecules have been investigated. The nanoparticles assembled with trypsin molecules exhibit superparamagnetism at room temperature with blocking temperature (~80 K) significantly lower than those without trypsin (~140 K). This is attributed to reduced magnetostatic couplings between particles due to increased distance between particles separated by trypsin molecules. Moreover, the

Taegyun Kim; Krishna Rajan; Mutsuhiro Shima

2006-01-01

225

Iron-Titanium Oxides and Oxygen Fugacities in Volcanic Rocks  

Microsoft Academic Search

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

I. S. E. Carmichael; J. Nicholls

1967-01-01

226

Porewater oxidation, dissolved phosphate and the iron curtain  

Microsoft Academic Search

The process of dissolved phosphate removal from aqueous solution, which occurs during oxidation of soluble ferrous compounds to insoluble ferric forms, was examined in soils of two tidal freshwater marshes. Sites of amorphous iron deposition and sorption or co-precipitation of phosphate were found to be in surface soils and along creekbanks, where both ion diffusion and porewater advection move dissolved

Randolph M. Chambers; William E. Odum

1990-01-01

227

Bioengineered iron-oxide nanocrystals: Applications in magnetic resonance imaging  

Microsoft Academic Search

Superparamagnetic Iron-Oxide nanoparticles (SPIO) are used as magnetic resonance imaging (MRI) contrast agents in clinical and research applications, effectively increasing the imaging sensitivity of MRI. Current clinical MRI applications utilizing SPIO are limited to liver and gastrointestinal imaging, but further bioengineering will expand the capabilities of SPIO enhanced MRI. This thesis presents different methods of bioengineering SPIO contrast agents for

Brian A. Larsen

2008-01-01

228

Pulsed laser deposition of iron oxide and ferrite films  

Microsoft Academic Search

Iron oxide and ferrite films were prepared by pulsed ruby laser evaporation from the respective bulk materials on alumina substrates. The variation in the film properties as a function of the substrate temperature and oxygen partial pressure during deposition was studied. Conversion electron Mo¨ssbauser spectroscopic analysis showed that the stoichiometry and microstructure of such films depend on these deposition conditions,

Sushama Joshi; Rashmi Nawathey; Vo N. Koinkar; V. P. Godbole; S. M. Chaudhari; S. B. Ogale; S. K. Date

1988-01-01

229

Iron Oxides in a Soil Developed from Basalt  

Microsoft Academic Search

A dusky red Oxisol forming on a tholeiitic basalt is found to contain varying proportion of aluminous hematite (Hm) and titanoaluminous maghemite (Mh) in the different size fractions. Maghemite is the main iron oxide in the sand and silt fractions whereas Hm is dominant in the clay fraction, together with gibbsite (Gb), kaolinite (Ka), rutile (Rt) (and probably anatase, An)

A. T. Goulart; J. D. FABRIS; M. E DE; JESUS FILHO; J. M. D. COEY; G. M. DA COSTA

1998-01-01

230

Oxidation resistant iron and nickel alloys for high temperature use  

NASA Technical Reports Server (NTRS)

Iron-base and nickel-base alloys exhibit good oxidation resistance and improved ductility with addition of small amounts of yttrium, tantalum /or hafnium/, and thorium. They can be used in applications above the operating temperatures of the superalloys, if high strength materials are not required.

Hill, V. L.; Misra, S. K.; Wheaton, H. L.

1970-01-01

231

Measurement of thermal properties of iron oxide pellets  

Microsoft Academic Search

The thermal properties of iron oxide pellets of different porosity and prepared by reduction at different rates were investigated in the range of room temperature to about 800°C. The thermal diffusivity a was measured by a laser flash method and the specific heat Cpwas measured by adiabatic scanning calorimetry. The thermal conductivity was calculated from the relation ?=aC?p, where ?

E. Takegoshi; Y. Hirasawa; S. Imura; T. Shimazaki

1984-01-01

232

Comparison of different bioreactor systems for indirect H 2S removal using iron-oxidizing bacteria  

Microsoft Academic Search

Microbial oxidation of ferrous iron may be available alternative method of producing ferric sulphate, which is a reagent used for removal of H2S from biogas. For practical use of this process, this study evaluated some of the most efficient bioreactor systems for continuous ferrous iron oxidation by iron-oxidizing bacteria. Performances of various bioreactor systems were compared based on the ferrous

Donghee Park; Dae Sung Lee; Jae Youl Joung; Jong Moon Park

2005-01-01

233

Arsenic Removal From Water by Adsorption Using Iron Oxide Minerals as Adsorbents: A Review  

Microsoft Academic Search

This review highlights the adsorption process by using iron oxide minerals as the adsorbent for arsenic removal from water. It includes the characteristics of arsenic in water and its toxicities, the adsorption process for arsenic removal from contaminated water, iron oxide minerals as the adsorbent, arsenic adsorption capacity on iron oxide minerals, main factors of the adsorption, arsenic removal from

Marisol Gallegos-Garcia; Kardia Ramírez-Muñiz; Shaoxian Song

2011-01-01

234

Arsenic Removal from Water by Adsorption Using Iron Oxide Minerals as Adsorbents: A Review  

Microsoft Academic Search

This review highlights the adsorption process by using iron oxide minerals as the adsorbent for arsenic removal from water. It includes the characteristics of arsenic in water and its toxicities, the adsorption process for arsenic removal from contaminated water, iron oxide minerals as the adsorbent, arsenic adsorption capacity on iron oxide minerals, main factors of the adsorption, and arsenic removal

Marisol Gallegos-Garcia; Kardia Ramírez-Muñiz; Shaoxian Song

2012-01-01

235

Superparamagnetic Nanocomposite of Silver\\/Iron-Oxide by Inert Gas Condensation  

Microsoft Academic Search

A superparamagnetic nanocomposite of silver and iron oxide was synthesized by gas condensation. The procedure involved (1) coevaporation of silver and iron, (2) in situ oxidation of iron particles, (3) in situ compaction, and (4) post-annealing in an inert or an oxidizing atmosphere. The magnetization plots against H\\/T fell on a single curve from room temperature to 160 K, thereby

Takao Yamamoto; Robert D. Shull; Prabhakar R. Bandaru; Frederic Cosandey; Horst W. Hahn

1994-01-01

236

Low-temperature hydration, oxidation and hydrogen production from Oman peridotite  

NASA Astrophysics Data System (ADS)

Peridotite in the shallow subsurface undergoes hydration and oxidation (serpentinization) during reactions with percolating fluids, generating hydrogen gas and releasing magnesium, iron, and calcium into solution. In the presence of fluids enriched in dissolved carbon dioxide, extensive precipitation of carbonate minerals occurs. This reaction has large-scale implications for mitigating climate change by providing a stable, geological carbon repository. The Samail Ophiolite in Oman contains large quantities of ultramafic rocks that are currently undergoing serpentinization at low temperatures (30°C) and forming carbonate minerals. The production of hydrogen gas provides an electron donor for subsurface chemolithoautotrophic life which can contribute to carbon cycling in the subsurface as microorganisms utilize carbon dioxide as an inorganic carbon source. Serpentinization reactions require the oxidation of Fe (II) to Fe (III) to reduce water to H2, but the mechanisms of hydrogen generation in low-temperature systems is poorly characterized. To address this question, we conducted low temperature (100°C) water-rock reactions with Oman peridotite, measured H2 and characterized the speciation of Fe-bearing minerals before and after water-rock interaction using micro-X-ray Absorption Near Edge Structure (?XANES) spectra obtained from Stanford Synchrotron Radiation Lightsource. The experimental water-rock reactions produce H2 at a pH of 9, which corresponds with observations of ultrabasic springs in the Samail ophiolite and the presence of H2 in these spring waters. Significant hydrogen production occurs for two and a half months of reaction, peaking at 400 nmol/gram of reacted peridotite and then steadily decreases with time. These maximum values of hydrogen production from Oman peridotite are greater than observed by our laboratory and others during aqueous alteration of San Carlos peridotite and isolated pyroxenes and olivines (e.g. Mayhew et al. 2013 [1]). The products of low-temperature serpentinization, as determined by least squares fits of model spectra to sample ?XANES spectra, include serpentine minerals, altered olivines and Fe(III) minerals. X-ray fluorescence (?XRF) maps of the distribution of Fe-bearing phases reveal extensive alteration of pyroxenes to a mixture of Fe(II) and Fe(III)-bearing phases during the 100°C water-rock interactions, while olivine grains are only incipiently altered along fracture networks, suggesting an important role for pyroxenes in low temperature H2-generating reactions. The serpentinization reactions in the Oman peridotite are producing significant levels of hydrogen at a low temperature within the habitability limit for life, suggesting Oman provides a subsurface niche for hydrogen-utilizing microorganisms. The microbiology of the Oman subsurface is important to consider when investigating carbonation reactions aimed for carbon capture and sequestration because microbial life can affect carbon availability, and the injection of CO2 into the aquifer may significantly alter the ecosystem. [1] Mayhew et al. 2013. Nature Geoscience

Miller, H. M.; Mayhew, L.; Templeton, A. S.

2013-12-01

237

Thermodynamics and kinetics of the sorption of copper ions by hydrated zirconium oxide  

SciTech Connect

On the basis of an investigation of the influence of the temperature on the equilibrium and kinetics of the sorption of copper ions from ammonium nitrate solution by hydrated zirconium oxide, estimates have been made of the thermodynamic functions describing this process, and calculations have been made of the effective diffusion coefficients of the copper and the apparent activation energy. It has been established that the selective absorption of the copper is dictated by the entropy increase of the system - at positive values of the enthalpy change - and the rate of the process is limited by internal diffusion.

Semenov, M.I.; Blokhin, A.A.; Taushkanov, V.P.

1986-10-20

238

Ferrates (iron(VI) and iron(V)): environmentally friendly oxidants and disinfectants.  

PubMed

Iron(VI) and iron(v), known as ferrates, are powerful oxidants and their reactions with pollutants are typically fast with the formation of non-toxic by-products. Oxidations performed by Fe(VI) and Fe(V) show pH dependence; faster rates are observed at lower pH. Fe(VI) shows excellent disinfectant properties and can inactivate a wide variety of microorganisms at low Fe(VI) doses. Fe(VI) also possesses efficient coagulation properties and enhanced coagulation can also be achieved using Fe(VI) as a preoxidant. The reactivity of Fe(V) with pollutants is approximately 3-5 orders of magnitude faster than that of Fe(VI). Fe(V) can thus be used to oxidize pollutants and inactivate microorganisms that have resistance to Fe(VI). The final product of Fe(VI) and Fe(V) reduction is Fe(III), a non-toxic compound. Moreover, treatments by Fe(VI) do not give any mutagenic/carcinogenic by-products, which make ferrates environmentally friendly ions. This paper reviews the potential role of iron(VI) and iron(V) as oxidants and disinfectants in water and wastewater treatment processes. Examples are given to demonstrate the multifunctional properties of ferrates to purify water and wastewater. PMID:15952452

Sharma, Virender K; Kazama, Futaba; Jiangyong, Hu; Ray, Ajay K

2005-03-01

239

Iron oxide nanotubes synthesized via template-based electrodeposition  

NASA Astrophysics Data System (ADS)

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 (?-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 (?-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. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr06924a

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

2014-04-01

240

Chromium Substitution Effect on the Magnetic Structure of Iron Oxides  

NASA Astrophysics Data System (ADS)

The local magnetic and electronic structures of chromium substituted iron oxide polycrystalline samples are investigated via Fe L-edge x-ray absorption near-edge structural and magnetic circular dichroism measurements. A strong dependence of atomic magnetic levels on the applied external magnetic field is observed. The magnetic behavior of Cr-doped iron oxides are determined to be dominantly governed by the d—d hybridization between Fe and Cr valence levels. In addition, the formation of CrO2 and Cr2O3 chromium oxide clusters in the sample are observed to determine the magnetic ordering, i.e. anti-ferromagnetic or ferromagnetic with the changing external magnetic fields. The results highly agree with the previous studies.

Osman Murat, Ozkendir

2012-05-01

241

Superparamagnetic iron oxide imaging of focal liver disease.  

PubMed

The use of iron oxide as a superparamagnetic contrast agent for magnetic resonance imaging of the liver has been described previously. When administered intravenously, superparamagnetic iron oxide (SPIO) is sequestered by the reticuloendothelial system causing significant shortening of the T2-relaxation time. The majority of the contrast is taken up by the reticuloendothelial tissue of the liver. Since tumours have reduced or absent reticuloendothelial tissue the effect on relaxation time is minimal and signal intensity differences between tumour and liver are increased. AMI 25 (Laboratoire Guerbet, Paris) is a colloidal solution of ferrous and ferric oxides. We have performed MR examination of the liver in 16 patients with focal liver lesions using AMI 25 as a superparamagnetic contrast agent. Our results indicate that SPIO significantly increases the conspicuity of focal lesions and the effect is greatest in malignant tumours. We observed no adverse reaction to this contrast agent. PMID:7729116

Taylor, P M; Hawnaur, J M; Hutchinson, C E

1995-04-01

242

Cyclohexane oxidation catalyzed by mononuclear iron(III) complexes  

Microsoft Academic Search

In this work, we present the oxidation of cyclohexane catalyzed by a family of mononuclear iron(III) complexes: [Fe(BMPA)Cl3] 1, [Fe(MPBMPA)Cl3] 2, [Fe(PBMPA)Cl2] 3 and [Fe(PABMPA)Cl2](ClO4) 4 using hydrogen peroxide or tert-butyl hydroperoxide as oxidant, in acetonitrile solution. These complexes were able to oxidize the cyclohexane into cyclohexanol and cyclohexanone with good yields. It was also possible to characterize by gas

Nakédia M. F. Carvalho; Adolfo Horn; O. A. C. Antunes

2006-01-01

243

Synthesis of A novel aminoalkoxide of iron by oxide one-pot process: Its sol-gel application to iron oxide powder  

Microsoft Academic Search

A low-cost and facile route to synthesize ferratrane complex, which can be employed as alkoxide precursor for iron oxide or doped iron oxide via sol-gel technique, has been developed from the reaction of a very inexpensive and plentiful starting materials via the oxide one-pot synthesis (OOPS) process. Ferratrane complex was directly synthesized from iron hydroxide, triethanolamine and ethylene glycol in

Manop Panapoy; Chutaporn Duangdee; Apirat Laobuthee; Bussarin Ksapabutr

244

Oxide Dispersion Strengthened Iron Aluminide by CVD Coated Powders  

SciTech Connect

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.

Asit Biswas Andrew J. Sherman

2006-09-25

245

Effect of diquat-induced oxidative stress on iron metabolism in male Fischer344 rats  

Microsoft Academic Search

Diquat toxicity causes iron-mediated oxidative stress; however, it remains unclear how diquat affects iron metabolism. Here,\\u000a we examined the effect of diquat-induced oxidative stress on iron metabolism in male Fischer-344 rats, with particular focus\\u000a on gene expression. Hepatic nonheme iron content was unchanged until 20 h after diquat treatment. Hepatic free iron levels\\u000a increased markedly in the early stages following treatment

Masashi Higuchi; Yasunaga Yoshikawa; Koichi Orino; Kiyotaka Watanabe

246

Hydration-responsive folding and unfolding in graphene oxide liquid crystal phases.  

PubMed

Graphene oxide is promising as a plate-like giant molecular building block for the assembly of new carbon materials. Its water dispersibility, liquid crystallinity, and ease of reduction offer advantages over other carbon precursors if its fundamental assembly rules can be identified. This article shows that graphene oxide sheets of known lateral dimension form nematic liquid crystal phases with transition points in agreement with the Onsager hard-plate theory. The liquid crystal phases can be systematically ordered into defined supramolecular patterns using surface anchoring, complex fluid flow, and microconfinement. Graphene oxide is seen to exhibit homeotropic surface anchoring at interfaces driven by excluded volume entropy and by adsorption enthalpy associated with its partially hydrophobic basal planes. Surprisingly, some of the surface-ordered graphene oxide phases dry into graphene oxide solids that undergo a dramatic anisotropic swelling upon rehydration to recover their initial size and shape. This behavior is shown to be a unique hydration-responsive folding and unfolding transition. During drying, surface tension forces acting parallel to the layer planes cause a buckling instability that stores elastic energy in accordion-folded structures in the dry solid. Subsequent water infiltration reduces interlayer frictional forces and triggers release of the stored elastic energy in the form of dramatic unidirectional expansion. We explain the folding/unfolding phenomena by quantitative nanomechanics and introduce the potential of liquid crystal-derived graphene oxide phases as new stimuli-response materials. PMID:21877716

Guo, Fei; Kim, Franklin; Han, Tae Hee; Shenoy, Vivek B; Huang, Jiaxing; Hurt, Robert H

2011-10-25

247

Iron oxidation kinetics and autotrophic bacteria in acidified environments  

SciTech Connect

Iron oxidation in the presence of lake sediment collected from an acidic alpine lake was three orders of magnitude faster than in filtered lakewater without sediment. When kinetic rates in the presence of sediment were normalized on a surface area basis, they fell within a narrow range, and the assumption of a first order dependence of rate on surface area was supported. The relative influence on heterogeneous rate of ferrous iron oxidation of the five metal oxides studied can be ranked SiO[sub 2] [approx] Al[sub 2]O[sub 3] [much lt] Fe[sub 2] O[sub 3] [approx] MnO[sub 2] [approx] TiO[sub 2], with a difference of three orders of magnitude separating the aluminum and iron oxides. The rate constants on a surface area basis were, respectively, 1.8 [times] 10[sup 10], 4.6 [times] 10[sup 10], 1.4 [times] 10[sup 13], 2.3 [times] 10[sup 13] and 5.3 [times] 10[sup 13]M[sup [minus]2] atm[sup [minus]1] sec[sup [minus]1]m[sup [minus]2]. Studies at low oxygen concentrations suggested that at low pO[sub 2] oxygenation may not be first order with respect to oxygen concentration. Biological processes were found to enhance oxidation kinetics by two orders of magnitude on a surface area basis in comparison with a gamma irradiated control. Oxidation rate in the presence of irradiated sediment was in turn approximately 130 times greater than for oxidation in deionized water. The importance of biological activity in environments exhibiting photoreduction of iron was further studied by development of a polyclonal antibody test for the detection of the iron oxidizing autotroph Thiobacillus ferrooxidans. T. ferrooxidans was found in the Snake River and its tributaries in the Colorado Rocky mountains. Tests for T. ferrooxidans in samples collected at Lake Cristallina, Canton Ticino, Switzerland and McDonalds Branch, Lebanon State Forest, New Jersey were negative.

Barry, R.C.

1993-01-01

248

Organic Matter and Silicon in Relation to the Crystallinity of Soil Iron Oxides  

Microsoft Academic Search

The contents of pyrophosphate-extractable carbon and iron, EDTA-extractable iron, dithionite-EDTA-extractable iron and silicon, total carbon, and sodium hydroxide-extractable silicon were determined in thirty soil samples from Denmark and Tanzania in order to investigate the general influence of organic matter and silicon on the crystallinity of soil iron oxides. The ratio between the contents of EDTA-extractable iron and dithionite-EDTA-extractable iron, both

Ole K. Borggaard

1985-01-01

249

Iron Requirement for Mn(II) Oxidation by Leptothrix discophora SS1  

Microsoft Academic Search

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 M iron\\/5.8 mM pyruvate) and sufficient iron (0.2 M iron\\/5.8 mM pyruvate). The influence

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

2009-01-01

250

Production and characterization of the nanostructured hollow iron oxide spheres and nanoparticles by aerosol route  

Microsoft Academic Search

Nanoshell hollow iron oxide (?-Fe2O3) spheres and nanoparticles were produced by ultrasonic spray pyrolysis (USP) method from iron(III) chloride salts. Iron oxide nanostructures were obtained by thermal decomposition of aerosol formed in the ultrasonic generator from aqueous solution of FeCl3 as a precursor. Hollow structure of iron oxide particles was controlled by reaction temperature changing between 600 and 200°C and

Sebahattin Gurmen; Burcak Ebin

2010-01-01

251

Intratumoral iron oxide nanoparticle hyperthermia and radiation cancer treatment  

NASA Astrophysics Data System (ADS)

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 hyperthermia is more effective than non-nanoparticle tumor heating techniques when similar thermal doses are applied. Initial electron and light microscopy studies of iron oxide nanoparticle and AMF exposed tumor cells show a rapid uptake of particles and acute cytotoxicity following AMF exposure.

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.

2007-03-01

252

Iron oxide nanotubes synthesized via template-based electrodeposition.  

PubMed

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 (?-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. PMID:24695621

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

2014-05-21

253

Thermodynamics of Uranyl Minerals: Enthalpies of Formation of Uranyl Oxide Hydrates  

SciTech Connect

The enthalpies of formation of seven uranyl oxide hydrate phases and one uranate have been determined using high-temperature oxide melt solution calorimetry: [(UO{sub 2}){sub 4}O(OH){sub 6}](H{sub 2}O){sub 5}, metaschoepite; {beta}-UO{sub 2}(OH){sub 2}; CaUO{sub 4}; Ca(UO{sub 2}){sub 6}O{sub 4}(OH){sub 6}(H{sub 2}O){sub 8}, becquerelite; Ca(UO{sub 2}){sub 4}O{sub 3}(OH){sub 4}(H{sub 2}O){sub 2}; Na(UO{sub 2})O(OH), clarkeite; Na{sub 2}(UO{sub 2}){sub 6}O{sub 4}(OH){sub 6}(H{sub 2}O){sub 7}, the sodium analogue of compreignacite and Pb{sub 3}(UO{sub 2}){sub 8}O{sub 8}(OH){sub 6}(H{sub 2}O){sub 2}, curite. The enthalpy of formation from the binary oxides, {Delta}H{sub f-ox}, at 298 K was calculated for each compound from the respective drop solution enthalpy, {Delta}H{sub ds}. The standard enthalpies of formation from the elements, {Delta}H{sub f}{sup o}, at 298 K are -1791.0 {+-} 3.2, -1536.2 {+-} 2.8, -2002.0 {+-} 3.2, -11389.2 {+-} 13.5, -6653.1 {+-} 13.8, -1724.7 {+-} 5.1, -10936.4 {+-} 14.5 and -13163.2 {+-} 34.4 kJ mol{sup -1}, respectively. These values are useful in exploring the stability of uranyl oxide hydrates in auxiliary chemical systems, such as those expected in U-contaminated environments.

K. Kubatko; K. Helean; A. Navrotsky; P.C. Burns

2005-05-11

254

Half-encapsulated Au nanoparticles by nano iron oxide: promoted performance of the aerobic oxidation of 1-phenylethanol.  

PubMed

Au nanoparticles half-encapsulated in nano iron oxide are prepared and loaded on alumina as a support. The donation of electrons from nano iron oxide to Au nanoparticles is detected and both the properties of gold and iron oxide are adjusted by the donation. The properties are different from the bulk iron oxide supported gold catalysts, in which the iron oxide is little influenced by the electronic interaction between the two components. The catalyst shows noticeably promoted activity for the aerobic oxidation of 1-phenylethanol over Au-Al2O3 and Au-bulk FeOx. The enhanced catalytic behavior may result from the cooperative effect between the Au nanoparticles and nano iron oxide. PMID:23978992

Zhao, Jianbo; Liu, Hong; Ye, Shuang; Cui, Yuming; Xue, Nianhua; Peng, Luming; Guo, Xuefeng; Ding, Weiping

2013-10-21

255

Half-encapsulated Au nanoparticles by nano iron oxide: promoted performance of the aerobic oxidation of 1-phenylethanol  

NASA Astrophysics Data System (ADS)

Au nanoparticles half-encapsulated in nano iron oxide are prepared and loaded on alumina as a support. The donation of electrons from nano iron oxide to Au nanoparticles is detected and both the properties of gold and iron oxide are adjusted by the donation. The properties are different from the bulk iron oxide supported gold catalysts, in which the iron oxide is little influenced by the electronic interaction between the two components. The catalyst shows noticeably promoted activity for the aerobic oxidation of 1-phenylethanol over Au-Al2O3 and Au-bulk FeOx. The enhanced catalytic behavior may result from the cooperative effect between the Au nanoparticles and nano iron oxide.

Zhao, Jianbo; Liu, Hong; Ye, Shuang; Cui, Yuming; Xue, Nianhua; Peng, Luming; Guo, Xuefeng; Ding, Weiping

2013-09-01

256

Iron Oxide Nanoparticle Assisted Purification and Mass Spectrometry Based Proteolytic Mapping of Intact CD4T Cells from Human Blood  

Microsoft Academic Search

Iron oxide nanoparticles have been used for many years as clinical applications. We have developed a rapid immunoaffinity isolation method of CD4T cells from a mixed cell population of human blood using iron oxide nanoparticles. Anti CD4-antibody has been attached to iron oxide nanoparticles after its surface modification. The antibody tagged iron oxide nanoparticle beads are simply incubated with the

Santi M. Mandal; Ananta K. Ghosh; Mahitosh Mandal

2008-01-01

257

Versatile ferrofluids based on polyethylene glycol coated iron oxide nanoparticles  

NASA Astrophysics Data System (ADS)

Versatile ferrofluids based on polyethylene glycol coated iron oxide nanoparticles were obtained by a facile protocol and thoroughly characterized. Superparamagnetic iron oxide nanoparticles synthesized using a modified forced hydrolysis method were functionalized with polyethylene glycol silane (PEG silane), precipitated and dried. These functionalized particles are dispersable in a range of solvents and concentrations depending on the desired properties. Examples of tunable properties are magnetic behavior, optical and magneto-optical response, thermal features and rheological behavior. As such, PEG silane functionalized particles represent a platform for the development of new materials that have broad applicability in e.g. biomedical, industrial or photonic environments. Magnetic, optical, magneto-optical, thermal and rheological properties of several ferrofluids based on PEG coated particles with different concentrations of particles dispersed in low molecular mass polyethylene glycol were investigated, establishing the applicability of such materials.

Brullot, W.; Reddy, N. K.; Wouters, J.; Valev, V. K.; Goderis, B.; Vermant, J.; Verbiest, T.

2012-06-01

258

Reflection spectra and magnetochemistry of iron oxides and natural surfaces  

NASA Technical Reports Server (NTRS)

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.

Wasilewski, P.

1978-01-01

259

Nanovectors for anticancer agents based on superparamagnetic iron oxide nanoparticles  

PubMed Central

During the last decade, the application of nanotechnologies for anticancer drug delivery has been extensively explored, hoping to improve the efficacy and to reduce side effects of chemotherapy. The present review is dedicated to a certain kind of anticancer drug nanovectors developed to target tumors with the help of an external magnetic field. More particularly, this work treats anticancer drug nanoformulations based on superparamagnetic iron oxide nanoparticles coated with biocompatible polymers. The major purpose is to focus on the specific requirements and technological difficulties related to controlled delivery of antitumoral agents. We attempt to state the problem and its possible perspectives by considering the three major constituents of the magnetic therapeutic vectors: iron oxide nanoparticles, polymeric coating and anticancer drug.

Douziech-Eyrolles, Laurence; Marchais, Herve; Herve, Katel; Munnier, Emilie; Souce, Martin; Linassier, Claude; Dubois, Pierre; Chourpa, Igor

2007-01-01

260

Potential toxicity of superparamagnetic iron oxide nanoparticles (SPION)  

PubMed Central

Superparamagnetic iron oxide nanoparticles (SPION) are being widely used for various biomedical applications, for example, magnetic resonance imaging, targeted delivery of drugs or genes, and in hyperthermia. Although, the potential benefits of SPION are considerable, there is a distinct need to identify any potential cellular damage associated with these nanoparticles. Besides focussing on cytotoxicity, the most commonly used determinant of toxicity as a result of exposure to SPION, this review also mentions the importance of studying the subtle cellular alterations in the form of DNA damage and oxidative stress. We review current studies and discuss how SPION, with or without different surface coating, may cause cellular perturbations including modulation of actin cytoskeleton, alteration in gene expression profiles, disturbance in iron homeostasis and altered cellular responses such as activation of signalling pathways and impairment of cell cycle regulation. The importance of protein-SPION interaction and various safety considerations relating to SPION exposure are also addressed.

Singh, Neenu; Jenkins, Gareth J.S.; Asadi, Romisa; Doak, Shareen H.

2010-01-01

261

Iron aluminide alloy container for solid oxide fuel cells  

DOEpatents

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.

Judkins, Roddie Reagan (Knoxville, TN); Singh, Prabhakar (Export, PA); Sikka, Vinod Kumar (Oak Ridge, TN)

2000-01-01

262

Enhancement of specific growth rate of iron-oxidizing bacteria by glucose  

Microsoft Academic Search

Thiobacillus ferrooxidans, isolated from mine water, utilized not only ferrous iron but also glucose to grow. By using ferrous-iron medium containing glucose, a 7-fold population increase was obtained after 96 h of incubation. The ability to oxidize ferrous iron was maintained during cultivation on the iron-glucose medium.

Takami Kai; You-ichi Suenaga; Keiji Matsuda; Takeshige Takahashi

1996-01-01

263

Iron inhibits the nitric oxide synthesis elicited by asbestos in murine macrophages  

Microsoft Academic Search

Crocidolite fibers stimulated nitric oxide synthase (NOS) activity and expression in glial and alveolar murine macrophages: this effect was inhibited by iron supplementation and enhanced by iron chelation. We suggest that in these cells crocidolite stimulates NOS expression by decreasing the iron bioavailability and activating an iron-sensitive transcription factor.

Elisabetta Aldieri; Dario Ghigo; Maura Tomatis; Laura Prandi; Ivana Fenoglio; Costanzo Costamagna; Gianpiero Pescarmona; Amalia Bosia; Bice Fubini

2001-01-01

264

Superparamagnetic Iron Oxide Nanoparticle Probes for Molecular Imaging  

Microsoft Academic Search

The field of molecular imaging has recently seen rapid advances in the development of novel contrast agents and the implementation\\u000a of insightful approaches to monitor biological processes non-invasively. In particular, superparamagnetic iron oxide nanoparticles\\u000a (SPIO) have demonstrated their utility as an important tool for enhancing magnetic resonance contrast, allowing researchers\\u000a to monitor not only anatomical changes, but physiological and molecular

Daniel L. J. Thorek; Antony K. Chen; Julie Czupryna; Andrew Tsourkas

2006-01-01

265

Effects of coating on magnetic properties in iron oxide nanoparticles  

Microsoft Academic Search

We have studied influence of surface modification on physical properties of iron oxide nanoparticles. We compared samples prepared by thermal decomposition of organic precursor in the presence of oleic acid, and the particles prepared by coprecipitation and partially coated by SiO2 or modified by citric acid and subsequently covered by photoactive TiO2 layer, respectively. Samples were characterised using TEM and

B. Bittova; J. Poltierova-Vejpravova; A. G. Roca; M. P. Morales; V. Tyrpekl

2010-01-01

266

Reductive-gas sensor using iron oxide nanowires  

Microsoft Academic Search

We have proposed and developed a new gas sensor using the change in the permeability of iron oxide nanowires. ?-Fe2O3 nanowires are synthesized by the simple annealing of Fe bulks or films at 375°C in air. When the surface of ?-Fe2O3 nanowires is changed by a reductive gas into ?-Fe2O3 or Fe3O4, the permeability of the nanowires increases. Our sensor

Yuu Uriya; Keisuke Nagato; Tetsuya Hamaguchi; Masayuki Nakao

2011-01-01

267

Biomedical applications of superparamagnetic iron oxide nanoparticles encapsulated within chitosan  

Microsoft Academic Search

Microspheres composed of superparamagnetic iron oxide (SPIO; Fe3O4; magnetite) nanoparticles and chitosan were developed as a novel MRI-detectable embolic material. Spherical SPIO nanoparticles were synthesized and embedded in polyglucosamine (chitosan) by sonochemical method. The ferrofluid, solution of SPIO-embedded chitosan, was sprayed on the surface of an alkali solution with a nozzle to produce SPIO-chitosan microspheres, from which 100–150?m microspheres were

Eun Hee Kim; Yangkyu Ahn; Hyo Sook Lee

2007-01-01

268

Mössbauer and magnetization studies of iron oxide nanocrystals  

Microsoft Academic Search

Monodisperse iron oxide nanocrystals have been produced following non-hydrolytic, thermal decomposition routes. Spherically\\u000a shaped particles with diameter of 4 and 12 nm and cubic shaped particles with an edge length of 9 nm have been studied. The\\u000a particles have been shown to consist of mainly maghemite. A reduction of the saturation magnetic hyperfine field is observed\\u000a for the 4 nm particles as compared

Lennart Häggström; Saeed Kamali; Tore Ericsson; Per Nordblad; Anwar Ahniyaz; Lennart Bergström

269

Deposition of iron oxide thin films by pulsed laser evaporation  

Microsoft Academic Search

Iron oxide films have been deposited on alumina substrates by pulsed ruby laser evaporation from a bulk ?-Fe2O3 pellet. The films have been characterized by using the techniques of conversion electron Mo¨ssbauer spectroscopy, Rutherford backscattering, and scanning electron microscopy. It is demonstrated that the stoichiometry of the deposited film can be varied between FeO and Fe3O4 by controlling the oxygen

S. B. Ogale; V. N. Koinkar; Sushama Joshi; V. P. Godbole; S. K. Date; A. Mitra; T. Venkatesan; X. D. Wu

1988-01-01

270

Iron oxide nanopowders prepared by the electroexplosion of wire  

Microsoft Academic Search

We have studied the effect of process parameters (supplied energy, oxygen concentration in the gas mixture, and others) on\\u000a the particle size and yield of iron oxide nanopowder obtained by the electroexplosion of wire. Under optimal conditions, up\\u000a to 25% of the particles in the powder were 15–20 nm in size (specific surface of up to 100 m2\\/g). Using several

Yu. A. Kotov; E. I. Azarkevich; A. M. Murzakaev; V. L. Kuznetsov; O. M. Samatov; T. M. Demina; O. R. Timoshenkova; A. K. Shtoltz

2007-01-01

271

Alteration of microbially precipitated iron oxides and hydroxides  

Microsoft Academic Search

Iron oxide and hydroxides can be precipitated from solution with both Fe{sup 2+} and Fe{sup 3+} states by a microbial consortium enriched from surface water draining a granitic batholith. The Fe{sup 2+}\\/Fe{sup 3+} ratio of the microbial precipitate is determined by both the initial environment and subsequent diagenesis. To evaluate the thermal aspects of diagenesis, biological precipitates, either largely Fe{sup

D. ANN BROWN; B. L. Sherriff; J. A. Sawicki

1998-01-01

272

Phosphorus removal by a synthetic iron oxide–gypsum compound  

Microsoft Academic Search

Phosphorus pollution is a major concern for soil and water management. This study assesses the phosphate and organic phosphorus removal capacity of an iron oxide–gypsum compound (named OX) in batch trials. Phosphate solutions ranging from 0.001 to 10 mg P l?1 were tested and OX proved to be an effective fixing agent. Solutions with different ionic strengths did not affect

Olivier Bastin; Frédéric Janssens; Joseph Dufey; Alain Peeters

1999-01-01

273

Schottky barrier formation using composite of polyaniline containing iron oxides  

NASA Astrophysics Data System (ADS)

A composite of polyaniline (PANI) containing iron oxides (Fe3O4) with nanometer size was prepared by a chemical method. The electrical properties of (PANI-Fe3O4) sandwich structure using ohmic gold and blocking aluminium electrodes were studied. The current density - voltage (J-V) characteristics for the device resemble the typical dark current versus applied voltage characteristic for conventional Schottky diode. Electronic parameters have been calculated using J-V and capacitance-voltage (C-V) measurements.

Motaweh, H. A.; Abdel-Malik, T. G.

2008-08-01

274

Sorption of two aromatic acids onto iron oxides: Experimental study and modeling  

Microsoft Academic Search

The transport of aromatic carboxylate compounds in the environment can be strongly influenced by adsorption onto certain minerals, such as iron oxides and hydroxides, found in ground water and soils. Batch experiments with five iron oxides were conducted to quantify the contributions to adsorption from different iron mineral surfaces and compare adsorption characteristics of selected organic acids (gentisic acid (GA)

K. Hanna

2007-01-01

275

Magnetic properties of microcrystalline iron (III) oxides and related materials as reflected in their Mössbauer spectra  

Microsoft Academic Search

Iron (III) oxides are common constituents of geologic materials, they are products and by-products of many industrial processes, they are involved in biological processes, and they are the outcome of iron and steel corrosion. In many of these examples the iron oxides are — fortuitously or intentionally — of small particle size, and as a consequence difficult, if not impossible,

E. Murad

1996-01-01

276

ARSENATE ADSORPTION ONTO ALUMINIUM AND IRON (HYDR)OXIDES AS AN ALTERNATIVE FOR WATER TREATMENT  

Microsoft Academic Search

The geochemical fates of iron and arsenic are so closely correlated that methods of arsenic removal from water are in general based on the high adsorptive affinity of this metalloid with iron (hydr)oxides. Under anoxic conditions, however, reductive dissolution of iron (hydr)oxides can take place, and arsenic may be released into the surrounding environment. The purpose of this study was

Juscimar Silva; Jaime W. V. Mello; Massimo Gasparon; Walter A. P. Abrahão; Tony Jong

2007-01-01

277

Surface Reactivity of Core Shell Iron-Iron Oxide Nanoclusters towards Breakdown of Carbon Tetrachloride  

NASA Astrophysics Data System (ADS)

Zero-valent iron (ZVI) is one of the technologies for groundwater remediation to reduce contaminants by removal of mobile chlorinated hydrocarbons. Iron-Iron oxide (Fe/Fe3O4) nanoclusters (NCs) made in our laboratory using cluster deposition technique have enhanced reactivity towards targeted contaminants due to the presence of ZVI protected by a passivated oxide shell. Here, we investigate the effectiveness of the Fe/Fe3O4 NCs in reducing carbon tetrachloride (CT) under laboratory conditions. The reactivity of the NCs was investigated by conducting unbuffered aqueous batch experiments to reduce CT at room temperature. Initial results show that 80% of the degradation of CT resulted in the formation of dichloromethane (DCM) and chloroform (CF); the remainder likely followed a competing pathway to yield nonhazardous products such as CO. The production of undesirable hydrogenated products such as DCM and CF suggests that the dominant reaction pathway occurs through hydrogen (H) atom transfer via H atoms generated by corrosion of the iron. Comparative experiments with ZVI NCs prepared by other methods are underway and the results will be reported. Future work is to analyze and understand factors that control the reaction pathways between desirable and undesirable products.

Tarsem S., Maninder K.; Qiang, You; Kim, Hongseok; Amonette, James E.; Baer, Donald R.

2012-02-01

278

A combustion process for the instant synthesis of ?-iron oxide  

Microsoft Academic Search

The preparation of y-Fe203, a technologically important recording material, involves precipitation of o~-FeOOH, dehydration-reduction of oI-FeOOH to F%O4 and the controlled oxidation of Fe30 4 to y-Fe203. The oxygen partial pressure, moisture content and temperature at which oxidation occurs are critical. Earlier, we reported the single-step preparation of 7-Fe203 and Co-doped 7-Fe203 [1-3] by the thermal decomposition\\/combustion of the iron(II)

K. Suresh; K. C. Patil

1993-01-01

279

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

PubMed

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

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

280

Cooperative Oxidation of CO on Iron-Oxide Particles  

Microsoft Academic Search

Theoretical electronic structure studies on CO oxidation in Fe2O3 nanoparticles have been carried out using first principles gradient corrected density functional approach. It is shown that while the direct oxidation of CO via surface oxygen atoms is not favorable in Fe2O2, it is favorable in Fe2O3 particles with a low barrier of 0.4 eV. We also propose a new, and

B. V. Reddy; F. Rasouli; M. R. Hajaligol; S. N. Khanna

2003-01-01

281

Characterization of iron(III) oxide and oxide-hydroxide as Sr-sorbent  

Microsoft Academic Search

Iron(III) hydroxide and oxide-hydroxide samples prepared by precipitation of 0.2M iron(III) nitrate solution by 5M NaOH and subsequently aged at pH 12 for times of up to 50 h have been characterized. The sorption properties towards Sr2+ were characterized by radiotracer method using85Sr, morphology of the samples was characterized by Transmission Electron Microscopy and Emanation Thermal Analysis. X-ray diffraction patterns

V. Balek; Z. Málek; J. Šubrt; A. Ždimera

1996-01-01

282

Iron(VI): Hypothetical Candidate for the Martian Oxidant  

NASA Astrophysics Data System (ADS)

As a result of the Viking missions of the early 1970s, the presence of a strong oxidant in martian soil was suggested. Here we present a hypothesis, testable by near-term missions, that iron(VI) is a likely contributor to the martian oxidative pool. In this context, ferrate(VI) salts, with FeO 42- anion, were studied for their spectral and oxidative properties. Ferrate(VI) has distinctive spectroscopic features that make it available for detection by remote sensing reflectance spectra and contact measurements via Mössbauer spectroscopy, and the relevant miniaturized instrumentation has been developed or is under way, while for the returned samples XANES spectroscopy is shown to be a method of choice. Ferrate(VI) is capable of splitting water to yield molecular oxygen, and oxidizing organic carbon into CO 2. These activities were strongly abated after treatment at elevated temperatures, similar to observations with martian soil samples in the Viking mission.

Tsapin, A. I.; Goldfeld, M. G.; McDonald, G. D.; Nealson, K. H.; Moskovitz, B.; Solheid, P.; Kemner, K. M.; Kelly, S. D.; Orlandini, K. A.

2000-09-01

283

Iron and chromium mixed-oxide nanocomposites  

NASA Astrophysics Data System (ADS)

Mixed oxides nanocomposites of the type xCr2O3-(1-x)?-Fe2O3 (x = 0.0-1.0) were synthesized using hydrothermal technique and characterized by X-ray diffraction (XRD) and Mössbauer spectroscopy. The same characterization methods were applied to a set of samples annealed at 600°C for 2 h. High chromium content correlated with occurrence of amorphization effects and onset of superparamagnetism in the as-obtained samples. The structure and properties of the thermally annealed samples, however, are dominated by the equilibrium of two phases, Cr:Fe2O3 and Fe:Cr2O3. The final (x = 1.0) particle size of the nanocomposite is close to 19 nm.

Sorescu, Monica; Diamandescu, L.; Tarabasanu-Mihaila, D.; Krupa, S.; Feder, M.

2010-02-01

284

Kinetics of Iron Oxidation by Thiobacillus ferrooxidans  

PubMed Central

A statistical relationship between the rate of ferric ion production by a strain of Thiobacillus ferrooxidans and various levels of cell concentration, Fe2+ concentration, Na+ concentration, and temperature was studied by a direct colorimetric method at 304 nm. The relationship was linear (90 to 93%), cross-product (3 to 4%), and quadratic (1 to 2%). The levels of cell concentration and Fe2+ concentration and their respective interactions with one another and the other factors had the most significant effects on the regression models. The solution of the quadratic response surface for optimum oxidation was a saddle point, and the predicted critical levels of temperature, cell concentration, Fe2+ concentration, and Na+ concentration ranged between ?6 and 2°C, 0.43 and 0.62 mg/ml, 72 and 233 mM, and 29.6 mM, respectively.

Okereke, Amechi; Stevens, S. Edward

1991-01-01

285

Iron\\/iron oxide core-shell nanoclusters for biomedical applications  

Microsoft Academic Search

Biocompatible magnetic nanoparticles have been found promising in several biomedical applications for tagging, imaging, sensing and separation in recent years. Most magnetic particles or beads currently used in biomedical applications are based on ferromagnetic iron oxides with very low specific magnetic moments of about 20–30 emu\\/g. Here we report a new approach to synthesize monodispersed core-shell nanostructured clusters with high specific

You Qiang; Jiji Antony; Amit Sharma; Joseph Nutting; Daniel Sikes; Daniel Meyer

2006-01-01

286

The impact of zirconium oxide nanoparticles on the hydration chemistry and biocompatibility of white Portland cement.  

PubMed

Zirconium oxide (ZrO2) has been nominated as a radiopacifying agent for use in MTA-like Portland cement-based root-filling materials. This research examines the impact of 20 wt% ZrO2 nanoparticles in the size range 50 to 75 nm on the early hydration chemistry of white Portland cement. Nano-ZrO2 was found to accelerate the degree of hydration by 26% within the first 24 h by presenting efficient nucleation sites for the precipitation and growth of the early C-S-H gel products. The presence of nano-ZrO2 was also found to divert the fate of the aluminium-bearing reaction products by lowering the ettringite to monosulphate ratio, reducing the size of the ettringite crystals and by increasing the Al:Si ratio of the C-S-H gel phase. The chemical and microstructural changes conferred upon the cement matrix by the nano-ZrO2 particles had a positive impact on in vitro biocompatibility with respect to MG63 osteosarcoma cells (via MTT assay). PMID:24088838

Li, Qiu; Deacon, Andrew D; Coleman, Nichola J

2013-01-01

287

Deep oxidation of 1,2-dichlorobenzene over Ti-doped iron oxide.  

PubMed

Ti-doped iron oxides with worm-like mesopores were successfully prepared using CTAB as the structure-directing agent. The as-prepared catalysts were characterized by XRD, Raman, H2-TPR, XPS, TEM, and N2 adsorption/desorption. The catalytic properties for oxidation of 1,2-dichlorobenzene (o-DCB) were investigated. The results showed that Fe18Ti2Ox with 10 mol% Ti-doping shows the best catalytic activity, and the total conversion of o-DCB can be obtained at 350 °C. Moreover, Fe18Ti2Ox exhibits higher stability, CO2 selectivity and lower apparent activation energy. The high activity of Fe18Ti2Ox could be ascribed to the combined factors including a smaller crystallite size, excellent low-temperature reducibility, high surface active oxygen concentration and a synergic effect between TiO2 and mixed iron oxide (?-Fe2O3 and ?-Fe2O3). Acetate and formate species as intermediates were detected by in situ FTIR spectroscopy. A two-step redox mechanism of o-DCB decomposition on the surface of Ti-doped iron oxides was proposed. These results demonstrated that Ti-doped iron oxides could be developed as environmentally friendly catalysts for the deep oxidation of chlorinated volatile organic pollutants. PMID:24832548

Ma, Xiaodong; Suo, Xueyue; Cao, Huiqin; Guo, Jie; Lv, Lu; Sun, Hongwen; Zheng, Meihua

2014-07-01

288

Iron Minerals Formed by a Nuclear Explosion in a Salt Bed.  

PubMed

The nuclear event, Gnome, was carried out in halite in the Salado formation and yielded a varied mineral assemblage. The iron suppor members reacted in the salt melt and formed several iron oxide phases. The magnetite which formed during the fireball stage reached in various ways with the environment to form higher oxides and hydrated oxides. PMID:17810111

Nathans, M W; Smith, D K; Kahn, J S

1965-11-19

289

Surface engineering of iron oxide nanoparticles for targeted cancer therapy.  

PubMed

Nanotechnology provides a flexible platform for the development of effective therapeutic nanomaterials that can interact specifically with a target in a biological system and provoke a desired response. Of the nanomaterials studied, iron oxide nanoparticles have emerged as one of top candidates for cancer therapy. Their intrinsic superparamagnetism enables noninvasive magnetic resonance imaging (MRI), and their biodegradability is advantageous for in vivo applications. A therapeutic superparamagnetic iron oxide nanoparticle (SPION) typically consists of three primary components: an iron oxide nanoparticle core that serves as both a carrier for therapeutics and contrast agent for MRI, a coating on the iron oxide nanoparticle that promotes favorable interactions between the SPION and the biological system, and a therapeutic payload that performs the designated function in vivo. Often, the design may include a targeting ligand that recognizes the receptors over-expressed on the exterior surface of cancer cells. The body is a highly complex system that imposes multiple physiological and cellular barriers to foreign objects. Thus, the success of a therapeutic SPION largely relies on the design of the iron oxide core to ensure its detection in MRI and the coatings that allow the nanoparticles to bypass these barriers. Strategies to bypass the physiological barriers, such as liver, kidneys, and spleen, involve tuning the overall size and surface chemistry of the SPION to maximize blood half-life and facilitate the navigation in the body. Strategies to bypass cellular barriers include the use of targeting agents to maximize uptake of the SPION by cancer cells and the employment of materials that promote desired intracellular trafficking and enable controlled drug release. The payload can be genes, proteins, chemotherapy drugs, or a combination of these molecules. Each type of therapeutic molecule requires a specific coating design to maximize the loading and to achieve effective delivery and release. In this Account, we discuss the primary design parameters in developing therapeutic SPIONs with a focus on surface coating design to overcome the barriers imposed by the body's defense system. We provide examples of how these design parameters have been implemented to produce SPIONs for specific therapeutic applications. Although there are still challenges to be addressed, SPIONs show great promise in the successful diagnosis and treatment of the most devastating cancers. Once the critical design parameters have been optimized, these nanoparticles, combined with imaging modalities, can serve as truly multifunctional theranostic agents that not only perform a therapeutic function but also provide instant clinical feedback, allowing the physician to adjust the treatment plan. PMID:21528865

Kievit, Forrest M; Zhang, Miqin

2011-10-18

290

Surface engineering of iron oxide nanoparticles for targeted cancer therapy  

PubMed Central

Conspectus Nanotechnology provides a flexible platform for the development of effective therapeutic nanomaterials that can interact specifically with a target in a biological system and provoke a desired biological response. Of the nanomaterials studied, iron oxide nanoparticles have emerged as one of top candidates for cancer therapy due to their intrinsic superparamagnetism that enables no-invasive magnetic resonance imaging (MRI) and biodegradability favorable for in vivo application. A therapeutic superparamagnetic iron oxide nanoparticle (SPION) typically consists of three primary components: an iron oxide nanoparticle core that serves as both a carrier for therapeutics and contrast agent for MRI, a coating on the iron oxide nanoparticle that promotes favorable interactions between the SPION and biological system, and a therapeutic payload that performs designated function in vivo. Often, a targeting ligand is also included in the design that recognizes the receptors over-expressed on cancer cells. The body is a highly complex system that imposes multiple physiological and cellular barriers to foreign objects. Thus, the success of a therapeutic SPION largely relies on the proper design of the iron oxide core to ensure MRI detectability and more critically, the coating to render the ability to bypass these barriers. Strategies to bypass the physiological barriers such as liver, kidneys, and spleen, involve tuning the overall size and surface chemistry of the SPION to maximize blood half-life and facilitate the navigation in the body. Strategies to bypass cellular barriers include the use of targeting agents to maximize uptake of the SPION by cancer cells, and employing materials that promote desired intracellular trafficking and enable controlled drug release. The payload can be genes, proteins, chemotherapy drugs, or a combination of them. Each therapeutic requires a specific coating design to maximize the loading and achieve effective delivery and release. In this Account, we discuss the primary design parameters in developing therapeutic SPIONs with a focus on surface coating design to overcome the barriers imposed by the body’s defense system and provide examples of how these design parameters have been implemented to produce therapeutic SPIONs for specific therapeutic applications. Although there are still challenges to be addressed, SPIONs show great promise in successful diagnosis and treatment of the most devastating cancers. Once critical design parameters have been optimized, these nanoparticles, combined with imaging modalities, can serve as a truly multi-functional theranostic agent that not only performs a therapeutic function, but provides instant treatment feedback for the physician to adjust the treatment plan.

Kievit, Forrest M.; Zhang, Miqin

2011-01-01

291

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

SciTech Connect

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

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

1984-07-01

292

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

SciTech Connect

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.

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

2008-10-01

293

REMOVAL OF ARSENIC FROM GROUNDWATER USING NATURALLY OCCURRING IRON OXIDES IN RURAL REGIONS OF MONGOLIA  

EPA Science Inventory

We have found that the iron oxide particles produced by grinding naturally occurring iron ores are very effective in removing arsenic from water. The arsenic adsorption isothermal of the particles h...

294

Results demonstrating techniques for enhancing electrochemical reactions involving iron oxide in slags and C in liquid iron  

NASA Astrophysics Data System (ADS)

Two techniques are described for the enhancement of the kinetics of reduction of iron oxide from slags by carbon in molten iron. Laboratory experiments have shown that the rate of iron oxide reduction by carbon-saturated iron can be increased by 5 to 10 times when the reaction is carried out under a reduced-pressure atmosphere. This effect is thought to be the result of the increased volumetric gas evolution through the slag layer and the associated increase in slag stirring. A model is presented, which relates the mass-transfer coefficient for ferrous ions in the slag to its stirring that is controlled by varying the ambient pressure. Additional laboratory experiments examined the electrochemical nature of iron oxide reduction from slag by carbon in liquid iron. Results indicate that the reduction of iron oxide from slag is increased in the presence of an applied electric field. The external circuit allows for the separation of the half-cell reactions associated with iron oxide reduction and decarburization and increases the reaction area available for the individual reactions. These results have significant implications for several important slag metal reactions, which occur during ironmaking and steelmaking operations.

Pal, Uday B.; MacDonald, Scott A.; Woolley, David W.; Powell, Adam C.

2005-04-01

295

Multifunctional iron-based metal oxide nanostructured materials: Synthesis, characterization, and properties  

Microsoft Academic Search

Iron-based metal oxides, such as iron oxides, iron-containing perovskites, and iron-containing perovskite composites or solid solutions, are promising materials for the design and synthesis of technologically important multifunctional materials. They are noteworthy for their unique and diverse properties including electronic, magnetic, and elastic ones. Stimulated by interest in the bulk properties of these materials as well as scientific potential and

Tae-Jin Park

2007-01-01

296

Catalytic oxidation of carbon monoxide over gold\\/iron hydroxide catalyst at ambient conditions  

Microsoft Academic Search

Catalytic oxidation of carbon monoxide at ambient conditions has been studied over gold\\/iron hydroxide catalysts. The catalyst was prepared by a precipitation method, in which the HAuCl4 was precipitated onto a suspension of the iron hydroxide support, with a low calcination temperature. The support was composed of the mixture of iron hydroxide and iron oxide, the specific surface area was

Kuo-Ching Wu; Yu-Lan Tung; Yi-Ling Chen; Yu-Wen Chen

2004-01-01

297

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

PubMed

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. PMID:14655711

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

2003-11-15

298

Formation of the first oxidized iron in the solar system  

NASA Astrophysics Data System (ADS)

Abstract-For fayalite formation times of several thousand years, and systems enriched in water by a factor of ten relative to solar composition, 1 ?m radius olivine grains could reach 2 mole% fayalite and 0.1 ?m 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 ?m 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> <div class="credits"> <p class="dwt_author">Grossman, Lawrence; Fedkin, Alexei V.; Simon, Steven B.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">299</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/22029755"> <span id="translatedtitle">Microwave-assisted hydrothermal synthesis of coralloid nanostructured nickel hydroxide <span class="hlt">hydrate</span> and thermal conversion to nickel <span class="hlt">oxide</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Coralloid nanostructured nickel hydroxide <span class="hlt">hydrate</span> has been successfully synthesized by a simple microwave-assisted hydrothermal process using nickel sulfate hexahydrate as precursor and urea as hydrolysis-controlling agent. A pure coralloid nanostructured nickel <span class="hlt">oxide</span> can be obtained from the nickel hydroxide <span class="hlt">hydrate</span> after calcination at 400 deg. C. The thermal property, structure and morphology of samples were characterized by thermogravimetry (TG), temperature-programmed reduction (TPR), X-ray (XRD), infrared spectroscopy (IR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM).</p> <div class="credits"> <p class="dwt_author">Lai, Teh-Long [Environmental Analysis Laboratory, Department of Chemistry, National Kaohsiung Normal University, Kaohsiung 802, Taiwan (China); Lai, Yuan-Lung [Department of Mechanical and Automation Engineering, Da-Yeh University, Changhua 515, Taiwan (China); Yu, Jen-Wei [Environmental Analysis Laboratory, Department of Chemistry, National Kaohsiung Normal University, Kaohsiung 802, Taiwan (China); Shu, Youn-Yuen, E-mail: shuyy@nknucc.nknu.edu.tw [Environmental Analysis Laboratory, Department of Chemistry, National Kaohsiung Normal University, Kaohsiung 802, Taiwan (China); Wang, Chen-Bin, E-mail: chenbin@ccit.edu.tw [Department of Applied Chemistry and Materials Science, Chung Cheng Institute of Technology, National Defense University, Tahsi, Taoyuan 335, Taiwan (China)</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-10-15</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">300</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/23372702"> <span id="translatedtitle">Experimental determination and thermodynamic modeling of methane and nitrogen <span class="hlt">hydrates</span> in the presence of THF, propylene <span class="hlt">oxide</span>, 1,4-dioxane and acetone</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Three-phase <span class="hlt">hydrate</span> equilibria of the methane+water+cyclicether and nitrogen+water+cyclicether systems were measured by employing the temperature search method. Three cyclic ethers of THF, propylene <span class="hlt">oxide</span> and 1,4-dioxane were chosen and their concentration was fixed at 3mol% relative to water. The addition of cyclic ethers caused the <span class="hlt">hydrate</span> equilibrium pressure to be drastically lowered at a specified temperature and equivalently the <span class="hlt">hydrate</span></p> <div class="credits"> <p class="dwt_author">Y.-T. Seo; S.-P. Kang; H. Lee</p> <p class="dwt_publisher"></p> <p class="publishDate">2001-01-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_14");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return showDiv("page_4");' 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onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">301</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/478809"> <span id="translatedtitle">Energy positions of <span class="hlt">oxide</span> semiconductors and photocatalysis with <span class="hlt">iron</span> complex <span class="hlt">oxides</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Energy position, bandgap, band structure, and their relationships were reviewed for various <span class="hlt">oxide</span> semiconductors, especially <span class="hlt">iron</span> <span class="hlt">oxides</span>, in photoelectrochemistry and photocatalysis, and the photocatalytic reduction of CO{sub 2} on some <span class="hlt">iron</span> complex <span class="hlt">oxides</span> was demonstrated. A linear relationship between bandgap and band edge was obtained for almost all the semiconductor <span class="hlt">oxides</span>. It was pointed out that a bandgap energy higher than about 2.46 eV is necessary for water photolysis without bias voltage. It was found that the energy positions of the band edge can be controlled by the electronegativity of the metal elements constituting the <span class="hlt">iron</span> complex <span class="hlt">oxides</span>. The relationship between the band structure and the charge transfer site was also examined. The photocatalytic reduction of CO{sub 2} to CH{sub 2}OH was demonstrated for CaFe{sub 2}O{sub 4} and Fe-Bi-Sr-Pb-O complex <span class="hlt">oxides</span>. The photocatalytic activity of the latter <span class="hlt">oxide</span> with a layer structure increased with increased Pb content. The catalytic mechanism was discussed from the point of view of the redox mechanism as well as the energy position of the band edge.</p> <div class="credits"> <p class="dwt_author">Matsumoto, Yasumichi [Kumamoto Univ. (Japan)] [Kumamoto Univ. (Japan)</p> <p class="dwt_publisher"></p> <p class="publishDate">1996-11-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">302</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19930022757&hterms=bender&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dbender"> <span id="translatedtitle">Low-temperature formation of magnetic <span class="hlt">iron</span> <span class="hlt">oxides</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Elemental analysis and magnetic measurements of the surface of Mars have indicated the presence of an <span class="hlt">iron</span> <span class="hlt">oxide</span> with a considerable magnetic moment. Identification of the <span class="hlt">oxide</span> phase(s) is an important subject as this may be used to identify the process of weathering on the martian surface as well as the composition of the Mars regolith itself. Consequently, interest was in evidence of new formation of strongly magnetic phases (e.g., magnetite, maghemite, feroxyhyte) in terrestrially derived Mars sample analogs. Within the group of Mars sample analogs derived from low-temperature weathering of basalts in Arctic regions, evidence of magnetic <span class="hlt">oxides</span> formed at the outermost weathering rind was never observed. However, in one instance where the weathering products accumulating in a crack of a basaltic stone were investigated, evidence of magnetite was found. The experimental details are presented.</p> <div class="credits"> <p class="dwt_author">Koch, Chr. Bender; Madsen, M. B.</p> <p class="dwt_publisher"></p> <p class="publishDate">1992-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">303</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/40675432"> <span id="translatedtitle">Sorption and filtration of metals using <span class="hlt">iron-oxide</span>-coated sand</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary"><span class="hlt">Iron</span> <span class="hlt">oxides</span> are good adsorbents for uncomplexed metals, some metal-ligand complexes, and many metal oxyanions. However, the adsorbent properties of these <span class="hlt">oxides</span> are not fully exploited in wastewater treatment operations because of difficulties associated with their separation from the aqueous phase. This paper describes experiments in which <span class="hlt">iron</span> <span class="hlt">oxides</span> were coated onto the surface of ordinary filter sand, and this</p> <div class="credits"> <p class="dwt_author">Mark M. Benjamin; Ronald S. Sletten; Robert P. Bailey; Thomas Bennett</p> <p class="dwt_publisher"></p> <p class="publishDate">1996-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">304</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/22818816"> <span id="translatedtitle">HRTEM characterization of phase changes and the occurrence of maghemite during catalysis by an <span class="hlt">iron</span> <span class="hlt">oxide</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Nanoparticle <span class="hlt">iron</span> <span class="hlt">oxide</span> catalyst was studied to determine the phase changes that occur during catalysis experiments and to determine if these changes could explain the <span class="hlt">oxidative</span> catalysis and deactivation mechanisms. The starting material was characterized as a mixture of glassy material, poorly crystalline <span class="hlt">iron</span> hydroxides, and a small amount of highly crystalline ?-Fe2O3. Under <span class="hlt">oxidative</span> (with respect to phase changes</p> <div class="credits"> <p class="dwt_author">Donald E. Miser; Eun-Jae Shin; Mohammad R. Hajaligol; Firooz Rasouli</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">305</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/42550813"> <span id="translatedtitle">Dissolution Morphology of <span class="hlt">Iron</span> (Oxy)(Hydr)<span class="hlt">Oxides</span> Exposed to the Dissimilatory <span class="hlt">Iron</span>-Reducing Bacterium Shewanella oneidensis MR1</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Atomic force microscopy was used to compare the dissolution morphology of <span class="hlt">iron</span> (oxy)(hydr)<span class="hlt">oxide</span> coated slides exposed to the dissimilatory <span class="hlt">iron</span> reducing bacterium Shewanella oneidensis MR-1 and a Type II protein secretion mutant unable to reduce <span class="hlt">iron</span> minerals without an exogenous electron shuttle. Dissolution morphologies of slides exposed to the wild-type organism were heterogeneous and consistent with the morphology of bacterial</p> <div class="credits"> <p class="dwt_author">Mengni Zhang; Jason R. Dale; Thomas J. DiChristina; Andrew G. Stack</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">306</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/23204460"> <span id="translatedtitle"><span class="hlt">Oxidation</span> of activated methylene groups to ketones catalyzed by new <span class="hlt">iron</span> phosphinooxazoline complexes and by <span class="hlt">iron</span>(II) triflate</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The study describes the first catalytic application of <span class="hlt">iron</span> phosphinooxazoline complexes and Fe(OTf)2 in <span class="hlt">oxidation</span> reactions. New <span class="hlt">iron</span> phosphinooxazoline (PHOX) complexes of the general formulation [Fe(PHOX)2]2+[OTf]2 (3, OTf=CF3SO3?) were synthesized in virtually quantitative yield from anhydrous Fe(OTf)2 and the corresponding PHOX ligands. The new complexes 3 as well as previously synthesized <span class="hlt">iron</span> PHOX complexes of the general formula [Fe(Cp)(CO)(PHOX)]+[I]? (2)</p> <div class="credits"> <p class="dwt_author">Matthew Lenze; Eike B. Bauer</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">307</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.sciencepub.net/newyork/0204/03_0620_model_chuka_ny0204.pdf"> <span id="translatedtitle">Model for Evaluating the Concentration of <span class="hlt">Iron</span> Upgraded during Pyrobeneficiation of <span class="hlt">Iron</span> <span class="hlt">Oxide</span> Ore Pelletized with Powdered Potassium Chlorate</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Model for predicting the concentration of <span class="hlt">iron</span> upgraded during pyrobeneficiation of <span class="hlt">iron</span> <span class="hlt">oxide</span> ore (pelletized with powdered potassium chlorate) has been derived. The model-predicted %Fe upgrades were found to agree a direct relationship between %Fe values and weight-input of KClO3 as exhibited by %Fe upgrades obtained from the experiment. The model; %Fe = 7.1367? indicates that <span class="hlt">iron</span> upgrade is dependent</p> <div class="credits"> <p class="dwt_author">Chukwuka Ikechukwu Nwoye; Stephen Obiji; Livinus Anyika; Uchenna Chukwuma Nwoye</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">308</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.springerlink.com/index/dq80406ht2707741.pdf"> <span id="translatedtitle"><span class="hlt">Oxidation</span> kinetics of <span class="hlt">iron</span> alloy drops in <span class="hlt">oxidizing</span> slags</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The kinetics of reactions between drops of Fe-C, Fe-C-P and Fe-C-S alloys and synthetic <span class="hlt">oxidizing</span> slags at 1550?C have been\\u000a studied. The reaction kinetics are obtained either from chemical analysis of quenched samples, or, for decarburization, *\\u000a by continuous measurement of the flow rate of evolved gas. The marked effect, on the kinetics, of the metal emulsification\\u000a during carbon removal</p> <div class="credits"> <p class="dwt_author">H. Gaye; P. V. Riboud</p> <p class="dwt_publisher"></p> <p class="publishDate">1977-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">309</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/23796630"> <span id="translatedtitle">RGD-conjugated <span class="hlt">iron</span> <span class="hlt">oxide</span> magnetic nanoparticles for magnetic resonance imaging contrast enhancement and hyperthermia.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">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 <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles with carboxyl groups were coupled to cyclic arginine-glycine-aspartic peptides for integrin ?(v)?? targeting. The particle size, magnetic properties, heating effect, and stability of the arginine-glycine-aspartic-ultrasmall superparamagnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> were measured. The arginine-glycine-aspartic-ultrasmall superparamagnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> demonstrates excellent stability and fast magneto-temperature response. Magnetic resonance imaging signal intensity of Bcap37 cells incubated with arginine-glycine-aspartic-ultrasmall superparamagnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> was significantly decreased compared with that incubated with plain ultrasmall superparamagnetic <span class="hlt">iron</span> <span class="hlt">oxide</span>. The preferential uptake of arginine-glycine-aspartic-ultrasmall superparamagnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> by target cells was further confirmed by Prussian blue staining and confocal laser scanning microscopy. PMID:23796630</p> <div class="credits"> <p class="dwt_author">Zheng, S W; Huang, M; Hong, R Y; Deng, S M; Cheng, L F; Gao, B; Badami, D</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-03-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">310</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=91939"> <span id="translatedtitle">Selective Inhibition of the <span class="hlt">Oxidation</span> of Ferrous <span class="hlt">Iron</span> or Sulfur in Thiobacillus ferrooxidans</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">The <span class="hlt">oxidation</span> of either ferrous <span class="hlt">iron</span> or sulfur by Thiobacillus ferrooxidans was selectively inhibited or controlled by various anions, inhibitors, and osmotic pressure. <span class="hlt">Iron</span> <span class="hlt">oxidation</span> was more sensitive than sulfur <span class="hlt">oxidation</span> to inhibition by chloride, phosphate, and nitrate at low concentrations (below 0.1 M) and also to inhibition by azide and cyanide. Sulfur <span class="hlt">oxidation</span> was more sensitive than <span class="hlt">iron</span> <span class="hlt">oxidation</span> to the inhibitory effect of high osmotic pressure. These differences were evident not only between <span class="hlt">iron</span> <span class="hlt">oxidation</span> by <span class="hlt">iron</span>-grown cells and sulfur <span class="hlt">oxidation</span> by sulfur-grown cells but also between the <span class="hlt">iron</span> and sulfur <span class="hlt">oxidation</span> activities of the same <span class="hlt">iron</span>-grown cells. Growth experiments with ferrous <span class="hlt">iron</span> or sulfur as an oxidizable substrate confirmed the higher sensitivity of <span class="hlt">iron</span> <span class="hlt">oxidation</span> to inhibition by phosphate, chloride, azide, and cyanide. Sulfur <span class="hlt">oxidation</span> 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.</p> <div class="credits"> <p class="dwt_author">Harahuc, Lesia; Lizama, Hector M.; Suzuki, Isamu</p> <p class="dwt_publisher"></p> <p class="publishDate">2000-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">311</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013PhDT.......145R"> <span id="translatedtitle">Cobalt-promoted <span class="hlt">Iron</span> <span class="hlt">Oxide</span> Nanoparticles for the Selective <span class="hlt">Oxidative</span> Dehydrogenation of Cyclohexane</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Recent work has shown that both cobalt and <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles are active for the <span class="hlt">oxidative</span> 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 <span class="hlt">iron</span> <span class="hlt">oxide</span> 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, <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles are doped with varying levels of cobalt to examine the effect of cobalt content and <span class="hlt">oxidation</span> state on the selectivity and activity of the <span class="hlt">iron</span> <span class="hlt">oxide</span> for the <span class="hlt">oxidative</span> dehydrogenation of cyclohexane, used as a model cyclic alkane in jet fuel. We have shown previously that small (˜5nm) cobalt <span class="hlt">oxide</span> nanoparticles favor the production of benzene over the partial dehydrogenation products cyclohexene and cyclohexadiene, or the complete <span class="hlt">oxidation</span> product carbon dioxide. It is the aim of this work to examine the surface of these cobalt-<span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles to determine the conditions most favorable for this selective <span class="hlt">oxidative</span> dehydrogenation. Cobalt-doped <span class="hlt">iron</span> 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-Ray Photoelectron Spectroscopy (XPS), BET N2 Physisorption, and CO Temperature Programmed Reduction (CO-TPR). These characterizations helped us to correlate the selectivity and activity data for each catalyst in an attempt to understand what roles the surface species played. It was found that <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles doped with 2-10 mol% cobalt formed a stable surface phase, enriched in Co (20 at%), independent of the bulk concentration. XPS measurements indicate this phase is rich in octahedral Co2+ cations. The selectivity to benzene was much higher in the Co-promoted <span class="hlt">iron</span> <span class="hlt">oxide</span> samples. This high concentration of octahedral cobalt(II) cations appear to have a strong promotional effect on the weakly held surface oxygen sites which have been shown previously to be the active sites for this reaction. Addition of cobalt also promoted the activity of the <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles; and stabilized them against particle growth under the reaction conditions, typically held at several different temperatures up to 370 °C, in a mixture of 0.4% cyclohexane and 4% oxygen, for several hours.</p> <div class="credits"> <p class="dwt_author">Rutter, Matthew</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">312</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013PhDT.......130W"> <span id="translatedtitle">Synthesis and Evaluation of Nanostructured Gold-<span class="hlt">Iron</span> <span class="hlt">Oxide</span> Catalysts for the <span class="hlt">Oxidative</span> Dehydrogenation of Cyclohexane</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Shape-controlled <span class="hlt">iron</span> <span class="hlt">oxide</span> and gold-<span class="hlt">iron</span> <span class="hlt">oxide</span> catalysts with a cubic inverse spinel structure were studied in this thesis for the <span class="hlt">oxidative</span> dehydrogenation of cyclohexane. The structure of <span class="hlt">iron</span> <span class="hlt">oxide</span> and gold-<span class="hlt">iron</span> <span class="hlt">oxide</span> catalysts has no major impact on their <span class="hlt">oxidative</span> dehydrogenation activity. However, the product selectivity is influenced. Both cyclohexene and benzene are formed on bare <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoshapes, while benzene is the only dehydrogenation product in the presence of gold. The selectivity of benzene over CO2 depends strongly on the stability of the <span class="hlt">iron</span> <span class="hlt">oxide</span> support and the gold-support interaction. The highest benzene yield has been observed on gold-<span class="hlt">iron</span> <span class="hlt">oxide</span> octahedra. {111}-bound nanooctahedra are highly stable in reaction conditions at 300 °C, while {100}-bound nanocubes start to sinter above 250 °C. The highest benzene yield has been observed on gold-<span class="hlt">iron</span> <span class="hlt">oxide</span> nanooctahedra, which are likely to have gold atoms, and few-atom gold clusters strongly-bound on their surface. Cationic gold appears to be the active site for benzene formation. An all-organic method to prepare Au-FeOx nano-catalysts is needed due to the inconvenience of the half-organic, half-inorganic synthesis process discussed above. Several methods from the literature to prepare gold-<span class="hlt">iron</span> <span class="hlt">oxide</span> nanocomposites completely in organic solvents were reviewed and followed. FeOx Au synthesis procedures in literatures are initially designed for a Au content of over 70%. This approach was tried here to prepare composites with a much lower Au content (2-5 atom. %). Heat treatment is required to bond Au and FeOx NPs in the organic-phase syntheses. Au-FeOx-4 was obtained as a selective catalyst for the ODH of cyclohexane. A Audelta+ peak is observed in the UV-Vis spectrum of sample Au-FeOx-4. This different Au delta+ form may be cationic Au nano-clusters interacting with the FeOx support. It has been demonstrated that cationic gold is responsible for dehydrogenation behavior. Furthermore, the yield of benzene in preliminary ODH tests of Au-FeOx-4 also proved the interaction between Au and FeOx. That explains the dehydrogenation activity of sample Au-FeO x-4. Therefore, the synthesis parameters of sample Au-FeOx-4 are recommended in further studies. Thermodynamic equilibria governing the cyclohexane dehydrogenation reaction and the phase transformation of the <span class="hlt">iron</span> <span class="hlt">oxides</span> used as catalysts have been considered as a reference, in a separate chapter. The all-organic method by thermolysis described in this thesis work can be used in preparations of Au/FeOx so that the density of Au cations is maximized. Gold deposition in an organic phase helps to manipulate the surface dispersion of Au, perhaps more precisely than doping Au in the inorganic phase. Such materials can be good not only for the ODH reaction, but also for the WGS reaction. This newly developed synthesis method is worth exploring in future.</p> <div class="credits"> <p class="dwt_author">Wu, Peng</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">313</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2835527"> <span id="translatedtitle">GAS-PHASE FLAME SYNTHESIS AND PROPERTIES OF MAGNETIC <span class="hlt">IRON</span> <span class="hlt">OXIDE</span> NANOPARTICLES WITH REDUCED <span class="hlt">OXIDATION</span> STATE</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary"><span class="hlt">Iron</span> <span class="hlt">oxide</span> nanoparticles of reduced <span class="hlt">oxidation</span> 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 <span class="hlt">oxidizer</span> into a surrounding flow of fuel. Unlike traditional flame methods, this configuration allows for the <span class="hlt">iron</span> 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 <span class="hlt">oxidation</span> 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.</p> <div class="credits"> <p class="dwt_author">Kumfer, Benjamin M; Shinoda, Kozo; Jeyadevan, Balachandran; Kennedy, Ian M</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">314</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/20228941"> <span id="translatedtitle">GAS-PHASE FLAME SYNTHESIS AND PROPERTIES OF MAGNETIC <span class="hlt">IRON</span> <span class="hlt">OXIDE</span> NANOPARTICLES WITH REDUCED <span class="hlt">OXIDATION</span> STATE.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary"><span class="hlt">Iron</span> <span class="hlt">oxide</span> nanoparticles of reduced <span class="hlt">oxidation</span> 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 <span class="hlt">oxidizer</span> into a surrounding flow of fuel. Unlike traditional flame methods, this configuration allows for the <span class="hlt">iron</span> 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 <span class="hlt">oxidation</span> 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</p> <div class="credits"> <p class="dwt_author">Kumfer, Benjamin M; Shinoda, Kozo; Jeyadevan, Balachandran; Kennedy, Ian M</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-03-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">315</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3690895"> <span id="translatedtitle">Anoxic photochemical <span class="hlt">oxidation</span> of siderite generates molecular hydrogen and <span class="hlt">iron</span> <span class="hlt">oxides</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Photochemical reactions of minerals are underappreciated processes that can make or break chemical bonds. We report the photooxidation of siderite (FeCO3) by UV radiation to produce hydrogen gas and <span class="hlt">iron</span> <span class="hlt">oxides</span> via a two-photon reaction. The calculated quantum yield for the reaction suggests photooxidation of siderite would have been a significant source of molecular hydrogen for the first half of Earth’s history. Further, experimental results indicate this abiotic, photochemical process may have led to the formation of <span class="hlt">iron</span> <span class="hlt">oxides</span> under anoxic conditions. The reaction would have continued through the Archean to at least the early phases of the Great <span class="hlt">Oxidation</span> Event, and provided a mechanism for <span class="hlt">oxidizing</span> the atmosphere through the loss of hydrogen to space, while simultaneously providing a key reductant for microbial metabolism. We propose that the photochemistry of Earth-abundant minerals with wide band gaps would have potentially played a critical role in shaping the biogeochemical evolution of early Earth.</p> <div class="credits"> <p class="dwt_author">Kim, J. Dongun; Yee, Nathan; Nanda, Vikas; Falkowski, Paul G.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">316</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/24742340"> <span id="translatedtitle">Pulsed-laser deposition of nanostructured <span class="hlt">iron</span> <span class="hlt">oxide</span> catalysts for efficient water <span class="hlt">oxidation</span>.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Amorphous <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles were synthesized by pulsed-laser deposition (PLD) for functionalization of indium-tin <span class="hlt">oxide</span> surfaces, resulting in electrodes capable of efficient catalysis in water <span class="hlt">oxidation</span>. These electrodes, based on earth-abundant and nonhazardous <span class="hlt">iron</span> metal, are able to sustain high current densities (up to 20 mA/cm(2)) at reasonably low applied potential (1.64 V at pH 11.8 vs reversible hydrogen electrode) for more than 1 h when employed as anodes for electrochemical water <span class="hlt">oxidation</span>. The good catalytic performance proves the validity of PLD as a method to prepare nanostructured solid-state materials for catalysis, enabling control over critical properties such as surface coverage and morphology. PMID:24742340</p> <div class="credits"> <p class="dwt_author">Orlandi, Michele; Caramori, Stefano; Ronconi, Federico; Bignozzi, Carlo A; Koura, Zakaria El; Bazzanella, Nicola; Meda, Laura; Miotello, Antonio</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-05-14</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">317</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3400701"> <span id="translatedtitle">In Vivo Clearance and Toxicity of Monodisperse <span class="hlt">Iron</span> <span class="hlt">Oxide</span> Nanocrystals</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Thermal decomposition of organometallic precursors have been found to generate highly crystalline <span class="hlt">iron</span> <span class="hlt">oxide</span> (IO) nanocrystals that display superior MR contrast and lower polydispersity than IO nanocrystals synthesized by aqueous precipitation. In the present study, the in vivo characteristics of IO nanocrystals prepared by the thermal decomposition route and then coated with a phospholipid containing a pendant poly(ethylene glycol) chain are examined. The size and surface chemistry of the IO nanocrystal influences the biodistibution, the rate of biodegradation and bioclearance, and the biodegradation products. We conclude that the in vivo fate of PEGylated monodisperse IO nanocrystals and the <span class="hlt">iron</span>, phospholipid, and oleic acid biodegradation products may influence the cellular environments in the organs and blood that can determine their safety in the body.</p> <div class="credits"> <p class="dwt_author">Gu, Luo; Fang, Ronnie H.; Sailor, Michael J.; Park, Ji-Ho</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">318</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2009JMMM..321.1951K"> <span id="translatedtitle">A new method for preparation of magnetite from <span class="hlt">iron</span> oxyhydroxide or <span class="hlt">iron</span> <span class="hlt">oxide</span> and ferrous salt in aqueous solution</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">In this study, a new method is proposed for the preparation of Fe 3O 4 from <span class="hlt">iron</span> oxyhydroxides (goethite, akaganeite, lepidocrocite, feroxyhyte and ferrihydrite) or <span class="hlt">iron</span> <span class="hlt">oxide</span> (hematite) and ferrous salt in aqueous solution. The product is magnetite with various particle sizes. Products are characterized by X-ray powder diffraction, IR spectra and vibrating sample magnetometery.</p> <div class="credits"> <p class="dwt_author">Kahani, S. A.; Jafari, M.</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-07-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">319</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/26625217"> <span id="translatedtitle">Au\\/<span class="hlt">iron</span> <span class="hlt">oxide</span> catalysts: temperature programmed reduction and X-ray diffraction characterization</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Gold on <span class="hlt">iron</span> <span class="hlt">oxides</span> catalysts have been characterized by temperature programmed reduction (TPR) and X-ray diffraction spectroscopy (XRD). The influence of preparation method, gold loading and pretreatment conditions on the reducibility of <span class="hlt">iron</span> <span class="hlt">oxides</span> have been investigated. On the impregnated Au\\/<span class="hlt">iron</span> <span class="hlt">oxide</span> catalysts as well as on the support alone the partial reduction of Fe(III) oxy(hydroxides) to Fe3O4 starts in</p> <div class="credits"> <p class="dwt_author">G Neri; A. M Visco; S Galvagno; A Donato; M Panzalorto</p> <p class="dwt_publisher"></p> <p class="publishDate">1999-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">320</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/39872439"> <span id="translatedtitle">Synthesis, phase transition, and magnetic property of <span class="hlt">iron</span> <span class="hlt">oxide</span> materials: effect of sodium hydroxide concentrations</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">In this paper, a class of novel <span class="hlt">iron</span> <span class="hlt">oxide</span> particles has been fabricated through surfactant-directed structure approach in\\u000a hydrothermal reaction. The obtained <span class="hlt">iron</span> <span class="hlt">oxide</span> nanostructures with distinct morphologies, such as rhombohedra, octahedral,\\u000a plate-like, as well as dendritic, can be obtained by gradually increasing the concentrations of NaOH. The as-prepared <span class="hlt">iron</span>\\u000a <span class="hlt">oxide</span> particles were characterized utilizing scanning electronic microscopy (SEM), X-ray</p> <div class="credits"> <p class="dwt_author">Xiaohui Guo; Shengliang Zhong; Ji Zhang; Wanv Wang; Jianjiang Mao; Gang Xie</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_15");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" 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showDiv("page_24");' href="#">24</a> <a onClick='return showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_18");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">321</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013MPLB...2750044G"> <span id="translatedtitle">An Effective-Substrate Method to Investigate AN <span class="hlt">Iron</span> Native <span class="hlt">Oxide</span> Layer on AN <span class="hlt">Iron</span> Substrate by Spectroscopic Ellipsometry</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">An effective-substrate method was presented to obtain the optical constants of an <span class="hlt">iron</span> native <span class="hlt">oxide</span> layer with unknown optical constants and film thickness on an <span class="hlt">iron</span> substrate with unknown optical constants by using spectroscopic ellipsometry (SE). "Thick" <span class="hlt">iron</span> films were deposited on silicon wafer by magnetron sputtering and were exposed to air at room temperature. They were measured by spectroscopic ellipsometry during this procedure at different time points from ten minutes to seven months. Pseudo optical constants were calculated from the initially measured data and were introduced into the modeling work of subsequent measurements as an effective substrate in order to obtain the optical constants and film thickness of the native <span class="hlt">oxide</span> layer. After obtaining the optical constants of the subsequent native <span class="hlt">oxide</span> layer, they were employed in the modeling work of the initially measured data and the optical constants of the <span class="hlt">iron</span> substrate and the film thickness of the initial native <span class="hlt">oxide</span> layer was obtained.</p> <div class="credits"> <p class="dwt_author">Gao, Shang; Lian, Jie; Sun, Zhaozong; Wang, Xiao; Li, Ping; Li, Qinghao</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-03-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">322</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/60290770"> <span id="translatedtitle"><span class="hlt">Iron</span>-titanium <span class="hlt">oxide</span> minerals and associated alteration phases in some uranium-bearing sandstones</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Detrital <span class="hlt">iron</span>-titanium (Fe--Ti) <span class="hlt">oxide</span> minerals of the ulvospinel-magnetite (titanomagnetite) and ilmenite-hematite (titanohematite) solid solution series are common in uranium-bearing sandstones. Alteration of Fe--Ti <span class="hlt">oxide</span> minerals in <span class="hlt">oxidizing</span> environments formed secondary products (primarily hematite) that are distinct from those produced under reducing conditions (<span class="hlt">iron</span> disulfide minerals). <span class="hlt">Oxidation</span> of sulfidized Fe--Ti <span class="hlt">oxide</span> minerals, by the processes that formed uranium rolls, produced ferric</p> <div class="credits"> <p class="dwt_author">R. L. Reynolds; M. B. Goldhaber</p> <p class="dwt_publisher"></p> <p class="publishDate">1978-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">323</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://oaspub.epa.gov/eims/eimsapi.dispdetail?deid=64608"> <span id="translatedtitle">AN EFFICIENT AND ECOFRIENDLY <span class="hlt">OXIDATION</span> OF ALKENES USING <span class="hlt">IRON</span> NITRATE AND MOLECULAR OXYGEN</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p class="result-summary">An environmentally friendly solventless <span class="hlt">oxidation</span> of alkenes is accomplished efficiently using relatively benign <span class="hlt">iron</span> nitrate as catalyst in the pressence of molecular oxygen under pressurized conditions....</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">324</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4115336"> <span id="translatedtitle">Tailoring the magnetic and pharmacokinetic properties of <span class="hlt">iron</span> <span class="hlt">oxide</span> magnetic particle imaging tracers</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Magnetic particle imaging (MPI) is an attractive new modality for imaging distributions of <span class="hlt">iron</span> <span class="hlt">oxide</span> 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 <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticle tracers with tailored magnetic and surface properties to achieve its full potential. In this review, we discuss optimizing <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles’ physical, magnetic, and pharmacokinetic properties for MPI, highlighting results from our recent work in which we demonstrated tailored, biocompatible <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticle tracers that provided two times better linear spatial resolution and five times better signal-to-noise ratio than Resovist.</p> <div class="credits"> <p class="dwt_author">Ferguson, Richard Mathew; Khandhar, Amit P; Arami, Hamed; Hua, Loc; Hovorka, Ondrej; Krishnan, Kannan M.</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">325</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3697499"> <span id="translatedtitle">Arsenic Bioremediation by Biogenic <span class="hlt">Iron</span> <span class="hlt">Oxides</span> and Sulfides</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">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 <span class="hlt">iron</span> 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) <span class="hlt">oxidation</span> or sulfate reduction, respectively. Without treatment, soluble As concentrations reached 3.9 ± 0.9 ?M 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 ?M, respectively, by the end of the experiment. Analyses using a range of biogeochemical and mineralogical tools indicated that sorption onto freshly formed hydrous ferric <span class="hlt">oxide</span> (HFO) and <span class="hlt">iron</span> 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 ?M), although soluble Mn release accompanying microbial Fe(II) <span class="hlt">oxidation</span> presents a potential health concern. In contrast, production of biogenic <span class="hlt">iron</span> sulfide minerals would not remediate the groundwater As concentration below the recommended WHO limit.</p> <div class="credits"> <p class="dwt_author">Couture, Raoul-Marie; Van Cappellen, Philippe; Corkhill, Claire L.; Charnock, John M.; Polya, David A.; Vaughan, David; Vanbroekhoven, Karolien; Lloyd, Jonathan R.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">326</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2797561"> <span id="translatedtitle">Conquering the Dark Side: Colloidal <span class="hlt">Iron</span> <span class="hlt">Oxide</span> Nanoparticles</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Nanomedicine approaches to atherosclerotic disease will have significant impact on the practice and outcomes of cardiovascular medicine. <span class="hlt">Iron</span> <span class="hlt">oxide</span> 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 <span class="hlt">iron</span> <span class="hlt">oxide</span> 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 <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticle T2 imaging agents, and which has theranostic potential in vascular diseases for detecting unstable ruptured plaque or treating atherosclerotic angiogenesis.</p> <div class="credits"> <p class="dwt_author">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.</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">327</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3405876"> <span id="translatedtitle">Superparamagnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles: magnetic nanoplatforms as drug carriers</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">A targeted drug delivery system is the need of the hour. Guiding magnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles with the help of an external magnetic field to its target is the principle behind the development of superparamagnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles (SPIONs) as novel drug delivery vehicles. SPIONs are small synthetic ?-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 <span class="hlt">iron</span> homeostasis, <span class="hlt">oxidative</span> 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.</p> <div class="credits"> <p class="dwt_author">Wahajuddin; Arora, Sumit</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">328</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2701397"> <span id="translatedtitle">Ligand-Enhanced Reactive <span class="hlt">Oxidant</span> Generation by Nanoparticulate Zero-Valent <span class="hlt">Iron</span> and Oxygen</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">The reaction of zero-valent <span class="hlt">iron</span> or ferrous <span class="hlt">iron</span> with oxygen produces reactive <span class="hlt">oxidants</span> capable of <span class="hlt">oxidizing</span> organic compounds. However, the <span class="hlt">oxidant</span> yield in the absence of ligands is too low for practical applications. The addition of oxalate, nitrilotriacetic acid (NTA), or ethylenediaminetetraacetic acid (EDTA) to oxygen-containing solutions of nanoparticulate zero-valent <span class="hlt">iron</span> (nZVI) significantly increases <span class="hlt">oxidant</span> yield, with yields approaching their theoretical maxima near neutral pH. These ligands improve <span class="hlt">oxidant</span> production by limiting <span class="hlt">iron</span> precipitation and by accelerating the rates of key reactions, including ferrous <span class="hlt">iron</span> <span class="hlt">oxidation</span> by oxygen and hydrogen peroxide. Product yields indicate that the oxic nZVI system produces hydroxyl radical (OH·) over the entire pH range in the presence of oxalate and NTA. In the presence of EDTA, probe compound <span class="hlt">oxidation</span> is attributed to OH· under acidic conditions and a mixture of OH· and ferryl ion (Fe[IV]) at circumneutral pH.</p> <div class="credits"> <p class="dwt_author">Keenan, Christina R.; Sedlak, David L.</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">329</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/23316187"> <span id="translatedtitle">Enriched <span class="hlt">Iron</span>(III)-Reducing Bacterial Communities are Shaped by Carbon Substrate and <span class="hlt">Iron</span> <span class="hlt">Oxide</span> Mineralogy.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary"><span class="hlt">Iron</span> (Fe) <span class="hlt">oxides</span> 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) <span class="hlt">oxides</span> (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) <span class="hlt">oxides</span> within sedimentary environments? Further, how do changes in Fe mineralogy shape <span class="hlt">oxide</span>-hosted microbial populations? To address these questions, we conducted a large-scale cultivation effort using various Fe(III) <span class="hlt">oxides</span> (ferrihydrite, goethite, hematite) and carbon substrates (glucose, lactate, acetate) along a dilution gradient to enrich for microbial populations capable of reducing Fe <span class="hlt">oxides</span> 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 <span class="hlt">oxide</span> 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 <span class="hlt">oxides</span> 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 <span class="hlt">oxide</span> 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. PMID:23316187</p> <div class="credits"> <p class="dwt_author">Lentini, Christopher J; Wankel, Scott D; Hansel, Colleen M</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">330</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3541049"> <span id="translatedtitle">Enriched <span class="hlt">Iron</span>(III)-Reducing Bacterial Communities are Shaped by Carbon Substrate and <span class="hlt">Iron</span> <span class="hlt">Oxide</span> Mineralogy</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary"><span class="hlt">Iron</span> (Fe) <span class="hlt">oxides</span> 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) <span class="hlt">oxides</span> (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) <span class="hlt">oxides</span> within sedimentary environments? Further, how do changes in Fe mineralogy shape <span class="hlt">oxide</span>-hosted microbial populations? To address these questions, we conducted a large-scale cultivation effort using various Fe(III) <span class="hlt">oxides</span> (ferrihydrite, goethite, hematite) and carbon substrates (glucose, lactate, acetate) along a dilution gradient to enrich for microbial populations capable of reducing Fe <span class="hlt">oxides</span> 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 <span class="hlt">oxide</span> 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 <span class="hlt">oxides</span> 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 <span class="hlt">oxide</span> 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.</p> <div class="credits"> <p class="dwt_author">Lentini, Christopher J.; Wankel, Scott D.; Hansel, Colleen M.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">331</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2865022"> <span id="translatedtitle">Bactericidal effect of <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles on Staphylococcus aureus</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">In order to study the effects of <span class="hlt">iron</span> <span class="hlt">oxide</span> (IO) nanoparticles on Staphylococcus aureus, IO nanoparticles were synthesized via a novel matrix-mediated method using polyvinyl alcohol (PVA). The IO nanoparticles were characterized by transmission electron microscopy and dynamic light scattering. Further, S. aureus were grown in the presence of three different IO nanoparticle concentrations for four, 12, and 24 hours. Live/dead assays were performed and the results provide evidence that IO/PVA nanoparticles inhibited S. aureus growth at the highest concentration (3 mg/mL) at all time points.</p> <div class="credits"> <p class="dwt_author">Tran, Nhiem; Mir, Aparna; Mallik, Dhriti; Sinha, Arvind; Nayar, Suprabha; Webster, Thomas J</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">332</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/17960940"> <span id="translatedtitle">Cellular level loading and heating of superparamagnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Superparamagnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> 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 <span class="hlt">iron</span> <span class="hlt">oxide</span> 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 <span class="hlt">iron</span> <span class="hlt">oxide</span> 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). <span class="hlt">Iron</span> <span class="hlt">oxide</span> 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 methods which can be used only for bulk tissue level treatments. In a mixture of normal and NP-loaded malignant tumor cells, the malignant cells were selectively destroyed after laser exposure leaving the unloaded normal cells intact. These studies hold promise for applications in cell purification and sorting and extracorporeal blood treatments in vitro. PMID:17960940</p> <div class="credits"> <p class="dwt_author">Kalambur, Venkat S; Longmire, Ellen K; Bischof, John C</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-11-20</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">333</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2873596"> <span id="translatedtitle">Evidence for equilibrium <span class="hlt">iron</span> isotope fractionation by nitrate-reducing <span class="hlt">iron(II)-oxidizing</span> bacteria</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary"><span class="hlt">Iron</span> isotope fractionations produced during chemical and biological Fe(II) <span class="hlt">oxidation</span> 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. <span class="hlt">Iron</span> 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) <span class="hlt">oxide</span>/hydroxide precipitates produced by the Fe(III) mineral encrusting, nitrate-reducing, Fe(II)-<span class="hlt">oxidizing</span> Acidovorax sp. strain BoFeN1. Isotopic fractionation in 56Fe/54Fe approached that expected for equilibrium conditions, assuming an equilibrium ?56FeFe(OH)3 – Fe(II)aq fractionation factor of +3.0 ‰. Previous studies have shown that Fe(II) <span class="hlt">oxidation</span> 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 <span class="hlt">oxidation</span>, and possible phase transformations of the Fe(III) precipitates. Attainment of Fe isotope equilibrium between Fe(III) <span class="hlt">oxide</span>/hydroxide precipitates and Fe(II)aq by neutrophilic, Fe(II)-<span class="hlt">oxidizing</span> bacteria or through abiologic Fe(II)aq <span class="hlt">oxidation</span> 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 biological and abiological Fe(II) <span class="hlt">oxidation</span>.</p> <div class="credits"> <p class="dwt_author">Kappler, A.; Johnson, C.M.; Crosby, H.A.; Beard, B.L.; Newman, D.K.</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">334</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3490434"> <span id="translatedtitle">Rapid Spectrophotometric Technique for Quantifying <span class="hlt">Iron</span> in Cells Labeled with Superparamagnetic <span class="hlt">Iron</span> <span class="hlt">Oxide</span> Nanoparticles: Potential Translation to the Clinic</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Labeling cells with superparamagnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> (SPIO) nanoparticles provides the ability to track cells by Magnetic Resonance Imaging. Quantifying intracellular <span class="hlt">iron</span> 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 <span class="hlt">iron</span> 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 <span class="hlt">iron</span> content of each sample. Standard curves demonstrated high linear correlation (R2 = 0.998) between absorbance spectra of <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles and concentration in known SPIO doped cells. Comparisons of the ST to ICP-MS or NMR relaxometric (R2) determinations of intracellular <span class="hlt">iron</span> 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 <span class="hlt">iron</span> = 0.66?g/ml. We have developed a rapid straightforward protocol that does not require overnight acid digestion for quantifying <span class="hlt">iron</span> <span class="hlt">oxide</span> content in magnetically labeled cells using readily available analytic instrumentation that should greatly expedite advances in comparing SPIO agents and protocols for labeling cells.</p> <div class="credits"> <p class="dwt_author">Dadashzadeh, Esmaeel R.; Hobson, Matthew; Bryant, L. Henry; Dean, Dana D.; Frank, Joseph A.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">335</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/8347958"> <span id="translatedtitle">Frequency dependence of MR relaxation times. II. <span class="hlt">Iron</span> <span class="hlt">oxides</span>.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">The frequency dependence of T1 and T2 was measured for homogeneous suspensions of magnetite and <span class="hlt">iron</span> oxyhydroxide particles in water with various concentrations of gelatin. The transverse relaxivity showed two types of behavior: (a) For magnetic particles, there was a rapid increase in T2 relaxivity with frequency, followed by a saturation plateau, which accorded with the Langevin magnetization function. From these curves, the magnetic moment of the particle domains was estimated to range from 0.8 to 6.3 x 10(4) Bohr magnetons. (b) For <span class="hlt">iron</span> oxyhydroxide (ferritin, ferrihydrite, and akaganéite) particles, T2 relaxivity increased linearly with frequency, the slope of the increase characteristic for each particle. T2 relaxivity generally increased with increasing gelatin concentration, corresponding to the measured decrease in the water diffusion coefficient. For <span class="hlt">iron</span> <span class="hlt">oxides</span>, homogeneously distributed either as iatrogenic agents or endogenous biominerals, these findings may aid in the interpretation of in vivo relaxivity and the effect on MR imaging. PMID:8347958</p> <div class="credits"> <p class="dwt_author">Bulte, J W; Vymazal, J; Brooks, R A; Pierpaoli, C; Frank, J A</p> <p class="dwt_publisher"></p> <p class="publishDate">1993-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">336</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012AGUFM.A33D0191Y"> <span id="translatedtitle">Red Dawn: Characterizing <span class="hlt">Iron</span> <span class="hlt">Oxide</span> Minerals in Atmospheric Dust</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Atmospheric dust is comprised of many components including small amounts of <span class="hlt">iron</span> <span class="hlt">oxide</span> minerals. Although the <span class="hlt">iron</span> <span class="hlt">oxides</span> 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 <span class="hlt">iron</span> <span class="hlt">oxide</span> 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 <span class="hlt">iron</span> <span class="hlt">oxides</span> 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 indicates the presence of nanogoethite and small particle sizes (< 30 nm). Magnetization experiments indicates that some of the nanogoethite has remanence blocking temperatures above 300 K (and hence larger particle sizes) but it must be a small fraction of the total grain distribution considering that goethite was not indicated at 300 K with Mössbauer. Likewise, Mössbauer spectra indicate that the hematite component is still above the Morin transition (TM=265 K) and in its canted antiferromagnetic state even at 4.2 K. Suppression of the Morin transition in hematite can occur due to reduced crystallinity, cation substitution (e.g., Ti4+, Al 3+), or small particle effects (d< 100 nm). Finally, we compared reflectance with a magnetic parameter (hard isothermal remanent magnetization, HIRM) for ferric <span class="hlt">oxide</span> abundance to assess the degree to which ferric <span class="hlt">oxide</span> in these samples might absorb solar radiation. In samples for which both parameters were obtained, HIRM and average reflectance over the visible wavelengths are correlated as a group (r2=0.24). These results indicate that the ferric <span class="hlt">oxide</span> minerals in Red Dawn dust absorb solar radiation. Much of this ferric <span class="hlt">oxide</span> occurs likely as grain coatings of nanohematite and nanogoethite, thereby providing high surface area to enhance absorption of solar radiation.</p> <div class="credits"> <p class="dwt_author">Yauk, K.; Ottenfeld, C. F.; Reynolds, R. L.; Goldstein, H.; Cattle, S.; Berquo, T. S.; Moskowitz, B. M.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">337</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/24748114"> <span id="translatedtitle"><span class="hlt">Iron</span> <span class="hlt">oxide</span> nanoparticles induce <span class="hlt">oxidative</span> stress, DNA damage, and caspase activation in the human breast cancer cell line.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Broad applications of <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles require an improved understanding of their potential effects on human health. In the present study, we explored the underlying mechanism through which <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles induce toxicity in human breast cancer cells (MCF-7). MTT (3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide) and lactate dehydrogenase assays were used to examine mechanisms of cytotoxicity. Concentration- and time-dependent cytotoxicity was observed in MCF-7 cells. <span class="hlt">Iron</span> <span class="hlt">oxide</span> nanoparticles were found to induce <span class="hlt">oxidative</span> stress evidenced by the elevation of reactive oxygen species generation, lipid peroxidation, and depletion of superoxide dismutase, glutathione, and catalase activities in MCF-7 cells. Nuclear staining was performed using 4', 6-diamidino-2-phenylindole (DAPI), and cells were analyzed with a fluorescence microscope. <span class="hlt">Iron</span> <span class="hlt">oxide</span> nanoparticles (60 ?g/ml) induced substantial apoptosis that was identified by morphology, condensation, and fragmentation of the nuclei of the MCF-7 cells. It was also observed that the <span class="hlt">iron</span> <span class="hlt">oxide</span> NPs induced caspase-3 activity. DNA strand breakage was detected by comet assay, and it occurred in a concentration- and time-dependent manner. Thus, the data indicate that <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles induced cytotoxicity and genotoxicity in MCF-7 cells via <span class="hlt">oxidative</span> stress. This study warrants more careful assessment of <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles before their industrial applications. PMID:24748114</p> <div class="credits"> <p class="dwt_author">Alarifi, Saud; Ali, Daoud; Alkahtani, Saad; Alhader, M S</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-06-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">338</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/23790206"> <span id="translatedtitle">Morphology of biogenic <span class="hlt">iron</span> <span class="hlt">oxides</span> records microbial physiology and environmental conditions: toward interpreting <span class="hlt">iron</span> microfossils.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Despite the abundance of Fe and its significance in Earth history, there are no established robust biosignatures for Fe(II)-<span class="hlt">oxidizing</span> micro-organisms. This limits our ability to piece together the history of Fe biogeochemical cycling and, in particular, to determine whether Fe(II)-<span class="hlt">oxidizers</span> played a role in depositing ancient <span class="hlt">iron</span> formations. A promising candidate for Fe(II)-<span class="hlt">oxidizer</span> biosignatures is the distinctive morphology and texture of extracellular Fe(III)-oxyhydroxide stalks produced by mat-forming microaerophilic Fe(II)-<span class="hlt">oxidizing</span> micro-organisms. To establish the stalk morphology as a biosignature, morphologic parameters must be quantified and linked to the microaerophilic Fe(II)-<span class="hlt">oxidizing</span> metabolism and environmental conditions. Toward this end, we studied an extant model organism, the marine stalk-forming Fe(II)-<span class="hlt">oxidizing</span> 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 ?m) zones of redox gradients, the bacteria converge into a narrow (100 ?m-1 mm) growth band. As cells <span class="hlt">oxidize</span> 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)-<span class="hlt">oxidizer</span> 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-Si hydrothermal deposit show that these morphological characteristics can be preserved in the microfossil record. This study demonstrates the potential of morphological biosignatures to reveal microbiology and environmental chemistry associated with geologic <span class="hlt">iron</span> formation depositional processes. PMID:23790206</p> <div class="credits"> <p class="dwt_author">Krepski, S T; Emerson, D; Hredzak-Showalter, P L; Luther, G W; Chan, C S</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-09-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">339</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/51979294"> <span id="translatedtitle">Biomineralogy and Morphology of the Marine <span class="hlt">Iron-oxidizing</span> Bacterium Mariprofundus ferrooxydans</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Mariprofundus ferrooxydans strain PV-1 is a lithoautotrophic <span class="hlt">iron-oxidizing</span> proteobacterium isolated from the Loihi Seamount in Hawaii. As cells grow, they form filaments upon which <span class="hlt">iron</span> minerals are deposited. Based on similarities in morphology, these structures appear to accumulate and form the bulk of <span class="hlt">iron</span> mats at Loihi. Furthermore, Mariprofundus has been observed in a number of other seafloor mat samples</p> <div class="credits"> <p class="dwt_author">C. S. Chan; D. Emerson; K. J. Edwards</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">340</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/57759969"> <span id="translatedtitle">Seasonal variations in number of acidophilic <span class="hlt">iron-oxidizing</span> bacteria and <span class="hlt">iron</span> <span class="hlt">oxidation</span> in the river contaminated with acid mine water</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Number of acidophilic <span class="hlt">iron-oxidizing</span> bacteria, soluble <span class="hlt">iron</span>, pH, and water temperature were measured seasonally at five sampling stations in the Akagawa River which is highly polluted by strongly acid mine water discharged from the abandoned Matsuo sulfur and <span class="hlt">iron</span>-sulfide mine area. Other environmental variables of the river water were also determined (titratable acidity. dissolved oxygen, electrical conductivity, sulfate, aluminum, ammonia</p> <div class="credits"> <p class="dwt_author">Norio Wakao; Kazuo Hanada; Yonekichi Sakurai; Hideo Shiota</p> <p class="dwt_publisher"></p> <p class="publishDate">1978-01-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_16");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" 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showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_19");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">341</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2915439"> <span id="translatedtitle">Modulation of intracellular <span class="hlt">iron</span> levels by <span class="hlt">oxidative</span> stress implicates a novel role for <span class="hlt">iron</span> in signal transduction</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Reactive oxygen species (ROS) display cytotoxicity that can be exacerbated by <span class="hlt">iron</span>. Paradoxically, HeLa cells treated with the ROS-generators menadione and 2,3-dimethoxy-1,4-naphthoquinone display increased free labile <span class="hlt">iron</span>. HeLa cells exposed to ROS undergo apoptosis but <span class="hlt">iron</span> chelation limits the extent of cell death suggesting the rise in intracellular <span class="hlt">iron</span> plays a signaling role in this pathway. This idea is supported by the fact that <span class="hlt">iron</span> chelation also alters the pattern of ROS-induced phosphorylation of stress-activated protein kinases SAPK/JNK and p38 MAPK. Thus, ROS-induced increases in cellular free <span class="hlt">iron</span> contribute to signaling events triggered during <span class="hlt">oxidative</span> stress response.</p> <div class="credits"> <p class="dwt_author">Deb, Suman; Johnson, Erin E.; Robalinho-Teixeira, Raquel L.</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">342</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=PB2014104605"> <span id="translatedtitle">Deposit Model for Magmatic <span class="hlt">Iron-Titanium-Oxide</span> Deposits Related to Proterozoic Massif Anorthosite Plutonic Suites.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">This descriptive model for magmatic <span class="hlt">iron-titanium-oxide</span> (Fe-Ti-<span class="hlt">oxide</span>) deposits hosted by Proterozoic age massif-type anorthosite and related rock types presents their geological, mineralogical, geochemical, and geoenvironmental attributes. Although these ...</p> <div class="credits"> <p class="dwt_author">D. L. Fey L. G. Woodruff S. W. Nicholson</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">343</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=DE88754297"> <span id="translatedtitle">Chemical Characterization of Transition Metal Spinel-Type <span class="hlt">Oxides</span>. Part 2. Manganese-Chromium-<span class="hlt">Iron</span> Spinels.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">Spinel <span class="hlt">oxides</span> of the type formed on Advanced Gas Cooled Reactor cladding contain manganese, chromium, and <span class="hlt">iron</span>. A range of standard spinels containing these metals have been prepared by solid state reaction of the appropriate single <span class="hlt">oxides</span> at temperatures...</p> <div class="credits"> <p class="dwt_author">G. C. Allen J. A. Jutson P. A. Tempest</p> <p class="dwt_publisher"></p> <p class="publishDate">1987-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">344</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/22840045"> <span id="translatedtitle">Application of a novel plasma-induced CD/MWCNT/<span class="hlt">iron</span> <span class="hlt">oxide</span> composite in zinc decontamination.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Herein, ?-cyclodextrin (?-CD) was grafted onto magnetic MWCNT/<span class="hlt">iron</span> <span class="hlt">oxide</span> particles by using low temperature plasma-induced technique to synthesize a novel nanocomposite. The prepared composite (denoted as CD/MWCNT/<span class="hlt">iron</span> <span class="hlt">oxide</span>) exhibited high magnetic property (saturation magnetization M(s)=37.8 emu/g) and good dispersion property in aqueous solution. Batch experiments were conducted to evaluate the application potential of CD/MWCNT/<span class="hlt">iron</span> <span class="hlt">oxide</span> in the decontamination of Zn(II) from aqueous solutions. The sorption amount of Zn(II) on CD/MWCNT/<span class="hlt">iron</span> <span class="hlt">oxide</span> was higher than that of Zn(II) on MWCNT/<span class="hlt">iron</span> <span class="hlt">oxides</span> and <span class="hlt">oxidized</span> MWCNTs, indicating that the grafted ?-CD could enhance the sorption capacity of CD/MWCNT/<span class="hlt">iron</span> <span class="hlt">oxide</span> composite toward Zn(II) by providing multiple hydroxyl functional groups. Due to its high magnetic, CD/MWCNT/<span class="hlt">iron</span> <span class="hlt">oxide</span> could be easily separated from aqueous solution with an external magnetic field. Regeneration studies suggested that CD/MWCNT/<span class="hlt">iron</span> <span class="hlt">oxide</span> can support long term use as a cost-effective material in sewage treatment with minimum replacement costs. PMID:22840045</p> <div class="credits"> <p class="dwt_author">Yang, Shitong; Guo, Zhiqiang; Sheng, Guodong; Wang, Xiangke</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-10-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">345</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/24799739"> <span id="translatedtitle">Evaluation of nanodispersion of <span class="hlt">iron</span> <span class="hlt">oxides</span> using various polymers.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">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> <div class="credits"> <p class="dwt_author">Tanaka, Y; Ueyama, H; Ogata, M; Daikoku, T; Morimoto, M; Kitagawa, A; Imajo, Y; Tahara, T; Inkyo, M; Yamaguchi, N; Nagata, S</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">346</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://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> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">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.</p> <div class="credits"> <p class="dwt_author">Tanaka, Y.; Ueyama, H.; Ogata, M.; Daikoku, T.; Morimoto, M.; Kitagawa, A.; Imajo, Y.; Tahara, T.; Inkyo, M.; Yamaguchi, N.; Nagata, S.</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">347</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/23974977"> <span id="translatedtitle">Magnetic tumor targeting of ?-glucosidase immobilized <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Directed enzyme/prodrug therapy (DEPT) has promising application for cancer therapy. However, most current DEPT strategies face shortcomings such as the loss of enzyme activity during preparation, low delivery and transduction efficiency in vivo and difficultly of monitoring. In this study, a novel magnetic directed enzyme/prodrug therapy (MDEPT) was set up by conjugating ?-glucosidase (?-Glu) to aminated, starch-coated, <span class="hlt">iron</span> <span class="hlt">oxide</span> magnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles (MNPs), abbreviated as ?-Glu-MNP, using glutaraldehyde as the crosslinker. This ?-Glu-MNP was then characterized in detail by size distribution, zeta potential, FTIR spectra, TEM, SQUID and magnetophoretic mobility analysis. Compared to free enzyme, the conjugated ?-Glu on MNPs retained 85.54% ± 6.9% relative activity and showed much better temperature stability. The animal study results showed that ?-Glu-MNP displays preferable pharmacokinetics characteristics in relation to MNPs. With an adscititious magnetic field on the surface of a tumor, a significant quantity of ?-Glu-MNP was selectively delivered into a subcutaneous tumor of a glioma-bearing mouse. Remarkably, the enzyme activity of the delivered ?-Glu in tumor lesions showed as high as 20.123±5.022 mU g(-1) tissue with 2.14 of tumor/non-tumor ?-Glu activity. PMID:23974977</p> <div class="credits"> <p class="dwt_author">Zhou, Jie; Zhang, Jian; David, Allan E; Yang, Victor C</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-09-20</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">348</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://mcb.asm.org/cgi/reprint/16/7/3781.pdf"> <span id="translatedtitle">Nitric <span class="hlt">Oxide</span> and <span class="hlt">Oxidative</span> Stress (H 2 O 2 ) Control Mammalian <span class="hlt">Iron</span> Metabolism by Different Pathways</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Several cellular mRNAs are regulated posttranscriptionally by <span class="hlt">iron</span>-responsive elements (IREs) and the cytosolic IRE-binding proteins IRP-1 and IRP-2. Three different signals are known to elicit IRP-1 activity and thus regulate IRE-containing mRNAs: <span class="hlt">iron</span> deficiency, nitric <span class="hlt">oxide</span> (NO), and the reactive oxygen intermediate hydrogen peroxide (H2O2). In this report, we characterize the pathways for IRP-1 regulation by NO and H2O2 andexaminetheireffectsonIRP-2.WeshowthattheresponsesofIRP-1andIRP-2toNOremarkablyresemble</p> <div class="credits"> <p class="dwt_author">KOSTAS PANTOPOULOS; GUNTER WEISS; ANDMATTHIAS W. HENTZE</p> <p class="dwt_publisher"></p> <p class="publishDate">1996-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">349</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/18491214"> <span id="translatedtitle">Silicon <span class="hlt">oxide</span> in an <span class="hlt">iron</span>(III) <span class="hlt">oxide</span> matrix: the sol–gel synthesis and characterization of Fe–Si mixed <span class="hlt">oxide</span> nanocomposites that contain <span class="hlt">iron</span> <span class="hlt">oxide</span> as the major phase</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The synthesis of Fe–Si mixed <span class="hlt">oxide</span> nanocomposite materials in which the <span class="hlt">iron</span>(III) <span class="hlt">oxide</span> is the major component is described. In a typical synthesis, the <span class="hlt">iron</span> <span class="hlt">oxide</span> precursor, FeCl3·6H2O, was mixed with a silica precursor, tetramethyl- or tetraethylorthosilicate, in ethanol and gelled using an organic epoxide. The composition of the resulting materials was varied from Fe\\/Si (mol\\/mol)=1–5 by adjusting the amount</p> <div class="credits"> <p class="dwt_author">Brady J. Clapsaddle; Alexander E. Gash; Joe H. Satcher; Randall L. Simpson</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">350</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2006JPhy4.136...99O"> <span id="translatedtitle">Mechanical properties of an <span class="hlt">iron</span> <span class="hlt">oxide</span> formed by corrosion in reinforced concrete structures</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The paper deals with elastic properties of <span class="hlt">iron</span> <span class="hlt">oxides</span> formed in reinforced concrete structures. Due to the difficulty to perform mechanical tests on the real <span class="hlt">oxides</span> presented in the form of (multiple) laminated stratums, the elastic modulus of <span class="hlt">iron</span> <span class="hlt">oxides</span> remains unknown. Young's moduli of porous compact “synthetic <span class="hlt">oxides</span>” in powder form, obtained in laboratory conditions, were measured from both acoustic measurements and oedometric tests. The elastic modulus of the compact polycrystalline <span class="hlt">iron</span> <span class="hlt">oxide</span> is deduced with respect to two models, a micromechanical one and a Hertz' theory. The full method is validated on a well-known material, the alumina.</p> <div class="credits"> <p class="dwt_author">Ouglova, A.; François, M.; Berthaud, Y.; Caré, S.; Foct, F.</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-11-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">351</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/22824444"> <span id="translatedtitle">Catalytic cracking of catechols and hydroquinones in the presence of nano-particle <span class="hlt">iron</span> <span class="hlt">oxide</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Nano-particle “<span class="hlt">iron</span> <span class="hlt">oxide</span>” was found to be an effective catalyst for the pyrolytic conversion of phenolic and other environmentally harmful aromatic compounds evolved during the combustion and pyrolysis of biomass. Catalytic cracking and <span class="hlt">oxidation</span> of catechol, 3-methylcatechol, hydroquinone, 2-methylhydroquinone, and 2,3-dimethylhydroquinone over the temperature range of 180–430°C and under partially <span class="hlt">oxidative</span> conditions were studied using nano-particle “<span class="hlt">iron</span> <span class="hlt">oxide</span>”. We employed</p> <div class="credits"> <p class="dwt_author">Eun-Jae Shin; Donald E. Miser; W. Geoffrey Chan; Mohammad R. Hajaligol</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">352</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/1012853"> <span id="translatedtitle">Atomistic Simulations of Uranium Incorporation into <span class="hlt">Iron</span> (Hydr)<span class="hlt">Oxides</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Atomistic simulations were carried out to characterize the coordination environments of U incorporated in three Fe-(hydr)<span class="hlt">oxide</span> minerals: goethite, magnetite, and hematite. The simulations provided information on U-O and U-Fe distances, coordination numbers, and lattice distortion for U incorporated in different sites (e.g., unoccupied versus occupied sites, octahedral versus tetrahedral) as a function of the <span class="hlt">oxidation</span> state of U and charge compensation mechanisms (i.e., deprotonation, vacancy formation, or reduction of Fe(III) to Fe(II)). For goethite, deprotonation of first shell hydroxyls enables substitution of U for Fe(III) with a minimal amount of lattice distortion, whereas substitution in unoccupied octahedral sites induced appreciable distortion to 7-fold coordination regardless of U <span class="hlt">oxidation</span> states and charge compensation mechanisms. Importantly, U-Fe distances of ~3.6 Å were associated with structural incorporation of U and cannot be considered diagnostic of simple adsorption to goethite surfaces. For magnetite, the octahedral site accommodates U(V) or U(VI) with little lattice distortion. U substituted for Fe(III) in hematite maintained octahedral coordination in most cases. In general, comparison of the simulations with available experimental data provides further evidence for the structural incorporation of U in <span class="hlt">iron</span> (hydr)<span class="hlt">oxide</span> minerals.</p> <div class="credits"> <p class="dwt_author">Kerisit, Sebastien N.; Felmy, Andrew R.; Ilton, Eugene S.</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-04-29</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">353</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/943067"> <span id="translatedtitle"><span class="hlt">Iron</span>(VI) : hypothetical candidate for the martian <span class="hlt">oxidant</span>.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">As a result of the Viking missions of the early 1970s, the presence of a strong <span class="hlt">oxidant</span> in martian soil was suggested. Here we present a hypothesis, testable by near-term missions, that <span class="hlt">iron</span>(VI) is a likely contributor to the martian <span class="hlt">oxidative</span> pool. In this context, ferrate(VI) salts, with FeO{sub 4}{sup 2-} anion, were studied for their spectral and <span class="hlt">oxidative</span> properties. Ferrate(VI) has distinctive spectroscopic features that make it available for detection by remote sensing reflectance spectra and contact measurements via Moessbauer spectroscopy, and the relevant miniaturized instrumentation has been developed or is under way, while for the returned samples XANES spectroscopy is shown to be a method of choice. Ferrate(VI) is capable of splitting water to yield molecular oxygen, and <span class="hlt">oxidizing</span> organic carbon into CO{sub 2}. These activities were strongly abated after treatment at elevated temperatures, similar to observations with martian soil samples in the Viking mission.</p> <div class="credits"> <p class="dwt_author">Tsapin, A. I.; Goldfeld, M. G.; McDonald, G. D.; Nealson, K. H.; Moskovitz, B.; Solheid, P.; Kemner, K. M.; Kelly, S. D.; Orlandini, K. A.; Environmental Research; Jet Propulsion Lab.; Univ. of Minnesota</p> <p class="dwt_publisher"></p> <p class="publishDate">2000-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">354</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=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> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">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-?(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> <div class="credits"> <p class="dwt_author">Percak-Dennett, E M; Beard, B L; Xu, H; Konishi, H; Johnson, C M; Roden, E E</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-05-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">355</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=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> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">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> <div class="credits"> <p class="dwt_author">Imamura, Seiichiro; Matsuba, Yoichi; Yamada, Etsu; Takai, Kenji; Utani, Kazunori [Kyoto Inst. of Tech. (Japan). Dept. of Chemistry] [Kyoto Inst. of Tech. (Japan). Dept. of Chemistry</p> <p class="dwt_publisher"></p> <p class="publishDate">1997-09-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">356</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/22823639"> <span id="translatedtitle">I. Adsorption mechanism of chlorophenols on <span class="hlt">iron</span> <span class="hlt">oxides</span>, titanium <span class="hlt">oxide</span> and aluminum <span class="hlt">oxide</span> as detected by infrared spectroscopy</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The adsorption of 2-chlorophenol, 2,3- and 2,4-dichlorophenols and 2,4,6-trichlorophenol in liquid and gas phase on <span class="hlt">iron</span>, titanium and aluminum <span class="hlt">oxides</span> seem to proceed in a similar way. Higher adsorption of chlorophenols either from gas phase or from aqueous solution was observed on ?-Fe2O3 than on ?-FeOOH. The low adsorption of chlorophenols from aqueous solution on <span class="hlt">oxide</span> surfaces suggests that hydrophobic</p> <div class="credits"> <p class="dwt_author">J. Bandara; J. A. Mielczarski; J. Kiwi</p> <p class="dwt_publisher"></p> <p class="publishDate">2001-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">357</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/23702194"> <span id="translatedtitle">Gas-phase thermochemistry of <span class="hlt">iron</span> <span class="hlt">oxides</span> and hydroxides: Portrait of a super-efficient suppressant</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">In the search for non-ozone-depleting Halon (CFâBr) replacements, several metals, including <span class="hlt">iron</span>, have been identified as super-efficient flame suppressants. Although some thermochemical data exist for the species that are thought to be most important in <span class="hlt">iron`s</span> flame chemistry, a more complete and accurate characterization of the thermochemistry of <span class="hlt">iron</span> <span class="hlt">oxides</span>, hydrides, and hydroxides is required to improve kinetic flame models.</p> <div class="credits"> <p class="dwt_author">C. Brian Kellogg; Karl K. Irikura</p> <p class="dwt_publisher"></p> <p class="publishDate">1999-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">358</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ig.pwr.wroc.pl/minproc/journal/pdf/1997/str31.pdf"> <span id="translatedtitle">THE ROLE OF CALCIUM HYDROXIDE IN THE PRODUCTION OF <span class="hlt">IRON</span> <span class="hlt">OXIDE</span> (MILL SCALE) PELLETS</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Mill scale which is a valuable secondary raw material produced from the rolling of steel sheets in steel making process, can be agglomerated by using the pelletizing technique for the production of <span class="hlt">iron</span> <span class="hlt">oxide</span> pellets. The physicochemical properties of <span class="hlt">iron</span> <span class="hlt">oxide</span> pellets produced from mill scale were found to be improved with calcium hydroxide addition. The amount of calcium hydroxide</p> <div class="credits"> <p class="dwt_author">Y. M. Z. AHMED; M. H. KHEDR; O. A. MOHAMED; M. E. H. SHALABI</p> <p class="dwt_publisher"></p> <p class="publishDate">1997-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">359</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/53736778"> <span id="translatedtitle">Laser-induced self-assembly of <span class="hlt">iron</span> <span class="hlt">oxide</span> nanostructures with controllable dimensionality</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The nanosecond pulsed laser ablation of fine <span class="hlt">iron</span> powder submerged under different liquid media (water, methanol, ethanol, and isopropanol) is used to rapidly produce a variety of <span class="hlt">iron</span> <span class="hlt">oxide</span> nanostructures from nanoparticles to nanowires and nanosheets. The dimensionality of the nanostructures is shown to be a consequence of two controllable mechanisms. The rapid <span class="hlt">oxidation</span>, collisional quenching, and coalescence of the</p> <div class="credits"> <p class="dwt_author">Simon J. Henley; Shafikuddin Mollah; Christina E. Giusca; S. Ravi P. Silva</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">360</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ecmjournal.org/journal/supplements/vol007supp01/pdf/vol007supp01a14.pdf"> <span id="translatedtitle">Development of biocompatible functionalized superparamagnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles for human cancer cell uptake</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">INTRODUCTION: The application of the different forms of <span class="hlt">iron</span> <span class="hlt">oxides</span> for radiological diagnostic procedures has gained wide acceptance in radiological practice (1), but therapeutic applications are still under investigation and development. Such applications are exploiting two major advantages of magnetic <span class="hlt">iron</span> <span class="hlt">oxides</span>: their low toxicity to human beings (2) and the possibility to exploit their outstanding magnetic properties, potentially allowing</p> <div class="credits"> <p class="dwt_author">H. Hofmann; J. Juillerat; A. Petri-Fink; M. Chastellain</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_17");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return showDiv("page_4");' 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class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_18");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return showDiv("page_4");' href="#">4</a> <a onClick='return showDiv("page_5");' href="#">5</a> <a onClick='return showDiv("page_6");' href="#">6</a> <a onClick='return showDiv("page_7");' href="#">7</a> <a onClick='return showDiv("page_8");' href="#">8</a> <a onClick='return showDiv("page_9");' href="#">9</a> <a onClick='return showDiv("page_10");' href="#">10</a> <a onClick='return showDiv("page_11");' href="#">11</a> <a onClick='return showDiv("page_12");' href="#">12</a> <a onClick='return showDiv("page_13");' href="#">13</a> <a onClick='return showDiv("page_14");' href="#">14</a> <a onClick='return showDiv("page_15");' href="#">15</a> <a onClick='return showDiv("page_16");' href="#">16</a> <a onClick='return showDiv("page_17");' href="#">17</a> <a onClick='return showDiv("page_18");' href="#">18</a> <a style="font-weight: bold;">19</a> <a onClick='return showDiv("page_20");' href="#">20</a> <a onClick='return showDiv("page_21");' href="#">21</a> <a onClick='return showDiv("page_22");' href="#">22</a> <a onClick='return showDiv("page_23");' href="#">23</a> <a onClick='return showDiv("page_24");' href="#">24</a> <a onClick='return showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_20");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">361</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4070692"> <span id="translatedtitle"><span class="hlt">Iron-Oxide</span> Minerals Affect Extracellular Electron-Transfer Paths of Geobacter spp</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Some bacteria utilize (semi)conductive <span class="hlt">iron-oxide</span> minerals as conduits for extracellular electron transfer (EET) to distant, insoluble electron acceptors. A previous study demonstrated that microbe/mineral conductive networks are constructed in soil ecosystems, in which Geobacter spp. share dominant populations. In order to examine how (semi)conductive <span class="hlt">iron-oxide</span> minerals affect EET paths of Geobacter spp., the present study grew five representative Geobacter strains on electrodes as the sole electron acceptors in the absence or presence of (semi)conductive <span class="hlt">iron</span> <span class="hlt">oxides</span>. It was found that <span class="hlt">iron-oxide</span> minerals enhanced current generation by three Geobacter strains, while no effect was observed in another strain. Geobacter sulfurreducens was the only strain that generated substantial amounts of currents both in the presence and absence of the <span class="hlt">iron</span> <span class="hlt">oxides</span>. Microscopic, electrochemical and transcriptomic analyses of G. sulfurreducens disclosed that this strain constructed two distinct types of EET path; in the absence of <span class="hlt">iron-oxide</span> minerals, bacterial biofilms rich in extracellular polymeric substances were constructed, while composite networks made of mineral particles and microbial cells (without polymeric substances) were developed in the presence of <span class="hlt">iron</span> <span class="hlt">oxides</span>. It was also found that uncharacterized c-type cytochromes were up-regulated in the presence of <span class="hlt">iron</span> <span class="hlt">oxides</span> that were different from those found in conductive biofilms. These results suggest the possibility that natural (semi)conductive minerals confer energetic and ecological advantages on Geobacter, facilitating their growth and survival in the natural environment.</p> <div class="credits"> <p class="dwt_author">Kato, Souichiro; Hashimoto, Kazuhito; Watanabe, Kazuya</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">362</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/61370997"> <span id="translatedtitle">Molding of electrode pastes in the presence of added <span class="hlt">iron</span> <span class="hlt">oxides</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">In the reported experiments, the process of molding pitch-coke mixtures in the presence of added <span class="hlt">iron</span> <span class="hlt">oxide</span> has been studied. The addition of <span class="hlt">iron</span> <span class="hlt">oxide</span> substantially changes the compressibility of the paste as the result of an improvement in its plastic properties. The nature of the dependence of the plasticity of the paste and of the density of the articles</p> <div class="credits"> <p class="dwt_author">G. D. Apalkova; G. V. Dmitrieva</p> <p class="dwt_publisher"></p> <p class="publishDate">1981-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">363</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/40318486"> <span id="translatedtitle"><span class="hlt">Iron</span> <span class="hlt">oxide</span> nanoparticles supported on ultradispersed diamond powders: Effect of the preparation procedure</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The state of the <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles, supported on ultradispersed diamond (UDD) powders is studied by X-ray diffraction, nitrogen physisorption, temperature-programmed reduction, FTIR and Mössbauer spectroscopy. Methanol decomposition to hydrogen and CO is used as a catalytic test. The peculiarities of the <span class="hlt">iron</span> <span class="hlt">oxide</span> species strongly depend on the detonation procedure used for the UDD powders preparation as well as</p> <div class="credits"> <p class="dwt_author">Momtchil Dimitrov; Ljubomira Ivanova; Daniela Paneva; Tanya Tsoncheva; Stavry Stavrev; Ivan Mitov; Christo Minchev</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">364</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/55380221"> <span id="translatedtitle">Magnetic Field Gradient Differentiation of Pedogenic <span class="hlt">Iron</span> <span class="hlt">Oxide</span> Minerals From Chinese Loess and Paleosols</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The correlation between paleosols and enhanced magnetic susceptibility on the Chinese Loess Plateau is by now well established. However, scant effort has focussed on the interpretation of paleoclimate via the specific <span class="hlt">iron</span> <span class="hlt">oxide</span> mineral assemblages contributing to the enhanced magnetic susceptibility signal. This paper focuses on the separation and identification of the pedogenic (< 1 micron) fraction of <span class="hlt">iron</span> <span class="hlt">oxide</span>\\/oxyhydroxide</p> <div class="credits"> <p class="dwt_author">L. Wagoner; A. Roth; M. J. Singer; K. Verosub</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">365</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ieecas.cn/qrjweb/papers/2006_S11.pdf"> <span id="translatedtitle">Spectroscopic analysis of <span class="hlt">iron-oxide</span> minerals in aerosol particles from northern China</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Diffuse reflectance spectrometry was used to study <span class="hlt">iron-oxide</span> minerals and to investigate the reflectance characteristics of eolian dust collected during the spring of 2001 and 2002 on bulk filters from three sites in northern China. The first derivatives of the reflectance spectra were consistent with signals from two <span class="hlt">iron-oxide</span> minerals, hematite and goethite, at wavelengths of 565 and 435 nm,</p> <div class="credits"> <p class="dwt_author">Z. X. Shen; J. J. Cao; X. Y. Zhang; R. Arimoto; J. F. Ji; W. L. Balsam; Y. Q. Wang; R. J. Zhang; X. X. Li</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">366</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.bme.gatech.edu/groups/bao/papers/LaConte%20JMagRes%202007.pdf"> <span id="translatedtitle">Coating thickness of magnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles affects R2 relaxivity</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Purpose: To evaluate the effect of coating thickness on the relaxivity of <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles. Materials and Methods: Monocrystalline superparamag- netic <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles (MIONs), coated with a poly- ethylene glycol (PEG)-modified, phospholipid micelle coat- ing, with different PEG molecular weights, were prepared. The particle diameters were measured with dynamic light scattering (DLS) and electron microscopy (EM). The R1 and</p> <div class="credits"> <p class="dwt_author">Leslie E. W. LaConte; Nitin Nitin; Omar Zurkiya; Daniela Caruntu; Charles J. O'Connor; Xiaoping Hu; Gang Bao</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">367</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/26999725"> <span id="translatedtitle">A magnetic poly(dimethylesiloxane) composite membrane incorporated with uniformly dispersed, coated <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">We report a new magnetic polymer membrane for MEMS application. The polymeric magnetic composite has coated <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles incorporated in a polydimethylsiloxane (PDMS) matrix. Existing magnetic polymeric materials have particle agglomeration problems, which result in rough surfaces and uneven mechanical and optical properties. We show that the use of <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles (10 nm in diameter) with fatty acid</p> <div class="credits"> <p class="dwt_author">Luna Cheng; Mu Chiao</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">368</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=250054"> <span id="translatedtitle">Kinetic Studies of <span class="hlt">Iron</span> <span class="hlt">Oxidation</span> by Whole Cells of Ferrobacillus ferrooxidans</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">A colorimetric assay was developed for studying the kinetics of <span class="hlt">iron</span> <span class="hlt">oxidation</span> with whole cells of the chemoautotroph, Ferrobacillus ferrooxidans. The assay was more advantageous than the conventional method of Warburg manometry because of its simplicity, rapidity, and the small amount of cells required. The assay measured Fe3+ as a chloride complex which absorbs at 410 nm. Kinetic analysis showed the apparent Km for <span class="hlt">iron</span> <span class="hlt">oxidation</span> to be 5.4 × 10?3m in an unbuffered system and 2.2 × 10?3m in the presence of ?-alanine-SO42? buffer. Glycine and ?-alanine buffers were used in the measurement of the pH optimum for <span class="hlt">iron</span> <span class="hlt">oxidation</span>; the optimum ranged from 2.5 to 3.8. The effect of pH was primarily on the Vmax while the Km remained constant. Added SO42? was found to stimulate <span class="hlt">iron</span> <span class="hlt">oxidation</span> by increasing the Vmax of <span class="hlt">iron</span> <span class="hlt">oxidation</span> by whole cells, but it did not affect the Km. Results of assays of <span class="hlt">iron</span> <span class="hlt">oxidation</span> in systems containing various mole percentages of SO42? and Cl? indicated that Cl? did not inhibit <span class="hlt">iron</span> <span class="hlt">oxidation</span> but that SO42? was required. Sulfate could be partially replaced by HPO42? and HAsO42? but not by BO3?, MoO42?, NO3?, or Cl?; formate and MoO42? inhibited <span class="hlt">iron</span> <span class="hlt">oxidation</span>.</p> <div class="credits"> <p class="dwt_author">Schnaitman, C. A.; Korczynski, M. S.; Lundgren, D. G.</p> <p class="dwt_publisher"></p> <p class="publishDate">1969-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">369</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/61366243"> <span id="translatedtitle">Utilization of simulated coal gases for reducing <span class="hlt">iron</span> <span class="hlt">oxide</span> pellets. Report of Investigations\\/1985</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The Bureau of Mines is investigating the use of complex gas mixtures, such as would be produced by coal gasification, for reducing <span class="hlt">iron</span> <span class="hlt">oxide</span> pellets. A semi-empirical model was developed to predict a priori the reduction rate of an <span class="hlt">iron</span> <span class="hlt">oxide</span> pellet in a laboratory tube furnace with simulated coal gases at a total pressure of 1 atm. The model</p> <div class="credits"> <p class="dwt_author">L. A. Haas; J. C. Nigro; R. K. Zahl</p> <p class="dwt_publisher"></p> <p class="publishDate">1985-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">370</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/24583326"> <span id="translatedtitle">The effect of protein <span class="hlt">oxidation</span> on <span class="hlt">hydration</span> and water-binding in pork packaged in an oxygen-enriched atmosphere.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">This study investigated the in situ <span class="hlt">oxidative</span> process of myofibrillar proteins in boneless pork loin chops (Longissimus lumborum) packaged in an oxygen-enriched atmosphere (HiOx: 80% O2/20% CO2), an air-permeable polyvinylchloride (PVC) overwrap, or a partial vacuum (VP) throughout display at 2°C for up to 14, 7, and 21days, respectively. Samples stored in HiOx were susceptible to lipid (TBARS) and protein (carbonyls, sulfhydryls, and aggregation) <span class="hlt">oxidation</span>, while samples in PVC and VP showed lesser <span class="hlt">oxidative</span> changes. Water-holding capacity of raw muscle decreased (P<0.05) when stored in HiOx but not in PVC and VP. Upon salt and phosphate brine marination, HiOx and PVC muscle samples had improved <span class="hlt">hydration</span> capacity during display compared with non-stored control, but display generally decreased <span class="hlt">hydration</span> of VP samples. The result was in agreement with myofibril structural changes. Despite the enhanced <span class="hlt">hydration</span>, HiOx muscle was least capable of withholding moisture upon cooking. PMID:24583326</p> <div class="credits"> <p class="dwt_author">Delles, Rebecca M; Xiong, Youling L</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-06-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">371</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/35248132"> <span id="translatedtitle"><span class="hlt">Oxidative</span> DNA damage (8-hydroxydeoxyguanosine) and body <span class="hlt">iron</span> status: a study on 2507 healthy people</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">To clarify the relationship of <span class="hlt">oxidative</span> stress and body <span class="hlt">iron</span> status, we detected urinary 8-hydroxydeoxyguanosine (8-OHdG) as a biomarker of <span class="hlt">oxidative</span> DNA damage, and measured serum ferritin and total <span class="hlt">iron</span>-binding capacity (TIBC), both reflecting body <span class="hlt">iron</span> store, on 2507 healthy people aged between 22 and 89 years (males, 1253; females, 1254). The urinary 8-OHdG excretion of males showed almost no</p> <div class="credits"> <p class="dwt_author">Masaru Nakano; Yoshikazu Kawanishi; Seika Kamohara; Yoshiko Uchida; Mami Shiota; Yuka Inatomi; Toyonori Komori; Katsumi Miyazawa; Kazumi Gondo; Ikuhiro Yamasawa</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">372</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/10149887"> <span id="translatedtitle">Enzymes of respiratory <span class="hlt">iron</span> <span class="hlt">oxidation</span>. Progress report, March 1990--June 1992</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">This report describes experimental progress in characterizing and identifying redox proteins in a number of <span class="hlt">iron-oxidizing</span> bacteria. Sections of the paper are entitled (1) In Situ electrolysis was explored to achieve enhanced yields of <span class="hlt">iron-oxidizing</span> bacteria, (2)Structure/function studies were performed on redox-active biomolecules from Thiobacillus ferrooxidans, (3) Novel redox-active biomolecules were demonstrated in other <span class="hlt">iron</span> autotrophs, and (4) New probes of metalloprotein electron-transfer reactions were synthesized and characterized.</p> <div class="credits"> <p class="dwt_author">Blake, R. II</p> <p class="dwt_publisher"></p> <p class="publishDate">1992-12-31</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">373</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/54150884"> <span id="translatedtitle">Rock magnetic parameters of dispersed metallic <span class="hlt">iron</span> and its <span class="hlt">oxidation</span> behavior</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">We established a small database for rock magnetic characteristics of native <span class="hlt">iron</span> using a synthetic powder of grain size in the range 1-5 mu m, i.e. multidomain state. Measurements were conducted on untreated samples with different <span class="hlt">iron</span> content (from 0.1 to 50 weight %) as well as on <span class="hlt">oxidized</span> samples. Controlled <span class="hlt">oxidation</span> of the native <span class="hlt">iron</span> to Fe-spinel was triggered</p> <div class="credits"> <p class="dwt_author">M. Antretter; P.-E. Mathé; P. Rochette</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">374</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/42772438"> <span id="translatedtitle">Adaptation of indigenous <span class="hlt">iron?oxidizing</span> bacteria for bioleaching of heavy metals in contaminated soils</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Indigenous <span class="hlt">iron?oxidizing</span> bacteria in soil were acclimated in three different contaminated soils to remove toxic heavy metals. The adaptation was carried out at a pH of 4.0 and a room temperature of 24 ± 2°C in a gyratory shaking incubator. The <span class="hlt">iron?oxidizing</span> microflora was adapted in three to four successive transfers. Ferrous <span class="hlt">iron</span> was supplemented by addition of FeSO4.7H2O. The</p> <div class="credits"> <p class="dwt_author">Gérald J. Zagury; K. Subba Narasiah; Rajeswar D. Tyagi</p> <p class="dwt_publisher"></p> <p class="publishDate">1994-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">375</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/20976671"> <span id="translatedtitle">Oxygen diffusion and <span class="hlt">oxide</span> phase formation in <span class="hlt">iron</span> under swift heavy ion irradiation</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">While irradiating thin <span class="hlt">iron</span> films deposited on silicon wafers with swift heavy ions in the energy range of a few MeV/amu, we have observed that the <span class="hlt">iron</span> surface <span class="hlt">oxidizes</span> due to the residual oxygen in the irradiation chamber, induced by the energy deposition by the ion. We have investigated these processes in detail using Rutherford backscattering spectrometry and conversion electron Moessbauer spectroscopy. We found that two different types of <span class="hlt">oxidation</span> processes were active, depending on the electronic energy loss of the incident ions. Irradiations above the track formation threshold S{sub ec}{sup Fe} of <span class="hlt">iron</span> resulted in diffusion-controlled dissolution of oxygen in the <span class="hlt">iron</span> bulk. Below S{sub ec}{sup Fe}, but above the track formation threshold of <span class="hlt">iron</span> <span class="hlt">oxide</span>, chemical reaction and homogeneous <span class="hlt">oxide</span> phase formation took place in a surface layer, while almost no oxygen diffusion into the <span class="hlt">iron</span> bulk could be observed anymore. These phenomena are discussed in terms of the oxygen mobility in the excited ion tracks in <span class="hlt">iron</span> and <span class="hlt">iron</span> <span class="hlt">oxide</span>. The effective diffusion constant estimated for swift heavy ion induced oxygen diffusion in <span class="hlt">iron</span> is larger by a factor of 100-1000 than the one reported for thermally activated oxygen diffusion in molten <span class="hlt">iron</span>.</p> <div class="credits"> <p class="dwt_author">Roller, Tobias; Bolse, Wolfgang [Institut fuer Strahlenphysik, Universitaet Stuttgart, Allmandring 3, 70569 Stuttgart (Germany)</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-02-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">376</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3625229"> <span id="translatedtitle">Dietary <span class="hlt">Iron</span> Concentration May Influence Aging Process by Altering <span class="hlt">Oxidative</span> Stress in Tissues of Adult Rats</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary"><span class="hlt">Iron</span> is an essential element. However, in its free form, <span class="hlt">iron</span> participates in redox-reactions, leading to the production of free radicals that increase <span class="hlt">oxidative</span> stress and the risk of damaging processes. Living organisms have an efficient mechanism that regulates <span class="hlt">iron</span> absorption according to their <span class="hlt">iron</span> content to protect against <span class="hlt">oxidative</span> damage. The effects of restricted and enriched-<span class="hlt">iron</span> diets on <span class="hlt">oxidative</span> stress and aging biomarkers were investigated. Adult Wistar rats were fed diets containing 10, 35 or 350 mg/kg <span class="hlt">iron</span> (adult restricted-<span class="hlt">iron</span>, adult control-<span class="hlt">iron</span> and adult enriched-<span class="hlt">iron</span> groups, respectively) for 78 days. Rats aged two months were included as a young control group. Young control group showed higher hemoglobin and hematocrit values, lower levels of <span class="hlt">iron</span> and lower levels of MDA or carbonyl in the major studied tissues than the adult control group. Restricted-<span class="hlt">iron</span> diet reduced <span class="hlt">iron</span> concentrations in skeletal muscle and <span class="hlt">oxidative</span> damage in the majority of tissues and also increased weight loss. Enriched-<span class="hlt">iron</span> diet increased hematocrit values, serum <span class="hlt">iron</span>, gamma-glutamyl transferase, <span class="hlt">iron</span> concentrations and <span class="hlt">oxidative</span> stress in the majority of tissues. As expected, young rats showed higher mRNA levels of heart and hepatic L-Ferritin (Ftl) and kidneys SMP30 as well as lower mRNA levels of hepatic Hamp and interleukin-1 beta (Il1b) and also lower levels of liver protein ferritin. Restricted-<span class="hlt">iron</span> adult rats showed an increase in heart Ftl mRNA and the enriched-<span class="hlt">iron</span> adult rats showed an increase in liver nuclear factor erythroid derived 2 like 2 (Nfe2l2) and Il1b mRNAs and in gut divalent metal transporter-1 mRNA (Slc11a2) relative to the control adult group. These results suggest that <span class="hlt">iron</span> supplementation in adult rats may accelerate aging process by increasing <span class="hlt">oxidative</span> stress while <span class="hlt">iron</span> restriction may retards it. However, <span class="hlt">iron</span> restriction may also impair other physiological processes that are not associated with aging.</p> <div class="credits"> <p class="dwt_author">Arruda, Lorena Fernandes; Arruda, Sandra Fernandes; Campos, Natalia Aboudib; de Valencia, Fernando Fortes; Siqueira, Egle Machado de Almeida</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">377</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3700657"> <span id="translatedtitle"><span class="hlt">Iron</span> overload causes <span class="hlt">oxidative</span> stress and impaired insulin signaling in AML-12 hepatocytes</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Background <span class="hlt">Iron</span> overload is associated with increased severity of nonalcoholic fatty liver disease (NAFLD) including progression to nonalcoholic steatohepatitis and hepatocellular carcinoma. Aims To identify potential role(s) of <span class="hlt">iron</span> in NAFLD, we measured its effects on pathways of <span class="hlt">oxidative</span> stress and insulin signaling in AML-12 mouse hepatocytes. Methods Rapid <span class="hlt">iron</span> overload was induced with 50 ?M ferric ammonium citrate and 8-hydroxyquinoline. Insulin response was measured by western blot of phospho-protein kinase B. Lipid content was determined by staining with oil red O. Reactive oxygen species (ROS) were measured by flow cytometry using 5-( -6)-chloromethyl-2?,7?-dichlorodihydrofluorescein diacetate. <span class="hlt">Oxidative</span> stress was measured by western blots for phospho-jnk and phospho-p38. Results <span class="hlt">Iron</span> increased ROS (p<0.001) and <span class="hlt">oxidative</span> stress (p<0.001), and decreased insulin signaling by 33% (p<0.001). Treatment with stearic or oleic acids (200 ?M) increased cellular lipid content and differentially modulated effects of <span class="hlt">iron</span>. Stearic acid potentiated <span class="hlt">iron</span>-induced ROS levels by 2-fold (p<0.05) and further decreased insulin response 59% (p<0.05) vs. <span class="hlt">iron</span> alone. In contrast, cells treated with oleic acid were protected against <span class="hlt">iron</span>-mediated injury; ROS levels were decreased by half (p<0.01) vs. <span class="hlt">iron</span> alone while insulin response was restored to control (untreated) levels. The anti-<span class="hlt">oxidant</span> curcumin reduced effects of <span class="hlt">iron</span> on insulin signaling, ROS, and <span class="hlt">oxidative</span> stress (p<0.01). Curcumin was similarly effective in cells treated with both stearic acid and <span class="hlt">iron</span>. Conclusions An in-vitro model of NAFLD progression is described in which <span class="hlt">iron</span>-induced <span class="hlt">oxidative</span> stress inhibits insulin signaling. Pathophysiological effects of <span class="hlt">iron</span> were increased by saturated fat and decreased by curcumin.</p> <div class="credits"> <p class="dwt_author">Messner, Donald J.; Rhieu, Byung Han; Kowdley, Kris V.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">378</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/22940973"> <span id="translatedtitle">Mechanisms in <span class="hlt">oxidation</span> and sintering of magnetite <span class="hlt">iron</span> ore green pellets</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Thermal volume changes and <span class="hlt">oxidation</span> mechanisms in magnetite <span class="hlt">iron</span> ore green pellets balled with 0.5% bentonite binder, as a function of raw material fineness and pellet porosity, are shown. When a pellet starts to <span class="hlt">oxidize</span>, a shell of hematite is formed around the pellet while the core still is magnetite. Dilatation curves were measured under non-<span class="hlt">oxidizing</span> and <span class="hlt">oxidizing</span> atmospheres to</p> <div class="credits"> <p class="dwt_author">S. P. E. Forsmo; P.-O. Samskog; B. M. T. Björkman</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">379</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1595343"> <span id="translatedtitle">The Intracellular Siderophore Ferricrocin Is Involved in <span class="hlt">Iron</span> Storage, <span class="hlt">Oxidative</span>-Stress Resistance, Germination, and Sexual Development in Aspergillus nidulans</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary"><span class="hlt">Iron</span> is required by most organisms, but an excess of this metal is potentially toxic. Consequently, uptake and intracellular storage of <span class="hlt">iron</span> are tightly controlled. The filamentous fungus A. nidulans lacks the <span class="hlt">iron</span> storage compound ferritin but possesses an intracellular siderophore, which is accumulated in a highly regulated manner as <span class="hlt">iron</span>-free desferri-ferricrocin or <span class="hlt">iron</span>-containing ferricrocin via transcriptional regulation of the nonribosomal peptide synthetase SidC. Biosynthesis of desferri-ferricrocin was low during <span class="hlt">iron</span>-replete conditions but up-regulated by both <span class="hlt">iron</span> starvation and intracellular <span class="hlt">iron</span> excess, the latter caused by either a shift from <span class="hlt">iron</span>-depleted to high-<span class="hlt">iron</span> conditions or deregulation of <span class="hlt">iron</span> uptake. Consequently, ferricrocin constituted only about 5% of the total <span class="hlt">iron</span> content under <span class="hlt">iron</span>-replete conditions but up to 64% during conditions of intracellular excess. In contrast, during <span class="hlt">iron</span> starvation, desferri-ferricrocin was accumulated, which appears to represent a proactive strategy to prevent <span class="hlt">iron</span> toxicity. Accumulation of the intracellular siderophore was also up-regulated by <span class="hlt">oxidative</span> stress, which underscores the intertwining of <span class="hlt">iron</span> metabolism and <span class="hlt">oxidative</span> stress. Lack of the intracellular siderophore causes pleiotropic effects, as SidC deficiency results in (i) less-efficient utilization of <span class="hlt">iron</span>, indicated by reduced growth under <span class="hlt">iron</span>-depleted conditions and a higher <span class="hlt">iron</span> demand under <span class="hlt">iron</span>-replete conditions, (ii) delayed germination under <span class="hlt">iron</span>-depleted conditions, (iii) increased sensitivity of conidia to <span class="hlt">oxidative</span> stress, and (iv) elimination of cleistothecia formation in homothallic conditions.</p> <div class="credits"> <p class="dwt_author">Eisendle, Martin; Schrettl, Markus; Kragl, Claudia; Muller, Daniela; Illmer, Paul; Haas, Hubertus</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">380</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/21702497"> <span id="translatedtitle">Gas-bubble effects on the formation of colloidal <span class="hlt">iron</span> <span class="hlt">oxide</span> nanocrystals.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">This paper reports that gas bubbles can be used to tailor the kinetics of the nucleation and growth of inorganic-nanocrystals in a colloidal synthesis. We conducted a mechanistic study of the synthesis of colloidal <span class="hlt">iron</span> <span class="hlt">oxide</span> nanocrystals using gas bubbles generated by boiling solvents or artificial Ar bubbling. We identified that bubbling effects take place through absorbing local latent heat released from the exothermic reactions involved in the nucleation and growth of <span class="hlt">iron</span> <span class="hlt">oxide</span> nanocrystals. Our results show that gas bubbles display a stronger effect on the nucleation of <span class="hlt">iron</span> <span class="hlt">oxide</span> nanocrystals than on their growth. These results indicate that the nucleation and growth of <span class="hlt">iron</span> <span class="hlt">oxide</span> nanocrystals may rely on different types of chemical reactions between the <span class="hlt">iron</span>-oleate decomposition products: the nucleation relies on the strongly exothermic, multiple-bond formation reactions, whereas the growth of <span class="hlt">iron</span> <span class="hlt">oxide</span> nanocrystals may primarily depend upon single-bond formation reactions. The identification of exothermic reactions is further consistent with our results in the synthesis of <span class="hlt">iron</span> <span class="hlt">oxide</span> nanocrystals with boiling solvents at reaction temperatures ranging from 290 to 365 °C, by which we determined the reaction enthalpy in the nucleation of <span class="hlt">iron</span> <span class="hlt">oxide</span> nanocrystals to be -142 ± 12 kJ/mol. Moreover, our results suggest that a prerequisite for effectively suppressing secondary nucleation in a colloidal synthesis is that the primary nucleation must produce a critical amount of nuclei, and this finding is important for a priori design of colloidal synthesis of monodispersed nanocrystals in general. PMID:21702497</p> <div class="credits"> <p class="dwt_author">Lynch, Jared; Zhuang, Jiaqi; Wang, Tie; LaMontagne, Derek; Wu, Huimeng; Cao, Y Charles</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-08-17</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_18");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a 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title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">381</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/44272862"> <span id="translatedtitle">Magnetic nanocomposites of mixed <span class="hlt">oxides</span> of <span class="hlt">iron</span> and barium synthesized under different <span class="hlt">oxidative</span> environments</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Synthesis of nanocomposites of mixed <span class="hlt">oxides</span> of <span class="hlt">iron</span> and barium in a copolymer matrix of aniline and formaldehyde using a chemical\\u000a route at room temperature is reported. X-ray diffraction, infrared, 57Fe Mossbauer studies, and scanning electron microscopy on as-synthesized samples, as well as samples obtained on heating at\\u000a different temperatures, are described. X-ray diffraction, 57Fe Mossbauer, and scanning electron microscopy</p> <div class="credits"> <p class="dwt_author">Shalima Gupta; Sajdha; H. N. Sheikh; B. L. Kalsotra; N. Kumar; S. Kumar</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">382</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2007AIPC..929..177K"> <span id="translatedtitle">A New Method of Preparation of Magnetite Nanoparticles from <span class="hlt">Iron</span> <span class="hlt">Oxide</span> Hydroxide</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">There are only two basic ways to produce magnetite at low temperature: by partial <span class="hlt">oxidation</span> of a FeII salt solution with <span class="hlt">oxidant</span> under alkaline condition and by precipitation of a mixed FeII/FeIII solution. At high temperature, the method involves reduction of <span class="hlt">iron</span> <span class="hlt">oxide</span> by a suitable reductant. Here we propose a new method of preparation of nanoparticle Fe3O4 from <span class="hlt">iron</span> oxyhydroxides (goethite, akaganeite, lepidocrocite, feroxyhyte and ferrihydrite) or <span class="hlt">iron</span> <span class="hlt">oxide</span> (hematite) and ferrous salt in aqueous solution. Products characterized by X-ray powder diffraction, IR spectra and vibrating sample magentometery.</p> <div class="credits"> <p class="dwt_author">Kahani, S. A.; Jafari, M.</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-08-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">383</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=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> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary"><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> <div class="credits"> <p class="dwt_author">Potter-McIntyre, S. L.; Chan, M. A.; McPherson, B. J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-03-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">384</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=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> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">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 ecotoxicological investigations. Our data suggest that the injection of ferric <span class="hlt">iron</span> nanoparticles as electron acceptors into contaminated aquifers for the enhancement of microbial contaminant degradation might develop into a novel bioremediation strategy.</p> <div class="credits"> <p class="dwt_author">Bosch, Julian; Fritzsche, Andreas; Frank-Fahle, Beatrice; Lüders, Tilmann; Höss, Sebastian; Eisenmann, Heinrich; Held, Thomas; Totsche, Kai U.; Meckenstock, Rainer U.</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-05-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">385</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3640798"> <span id="translatedtitle">Arsenic removal from water using flame-synthesized <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles with variable <span class="hlt">oxidation</span> states</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">We utilized gas-phase diffusion flame synthesis, which has potential for large-scale production of metal <span class="hlt">oxide</span> nanoparticles, to produce <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles (IONPs) with variable <span class="hlt">oxidation</span> states. The efficacy of these materials in removal of arsenate (As(V) ) from water was assessed. Two different flame configurations, a diffusion flame (DF) and an inverse diffusion flame (IDF), were employed to synthesize six different IONPs by controlling flame conditions. The IONPs produced in the IDF configuration (IDF-IONPs) had smaller particle diameters (4.8 – 8.2 nm) and larger surface areas (141–213 m2/g) than the IONPs produced in the DF configuration (29 nm, 36 m2/g), which resulted in their higher adsorption capacities. As(V) adsorption capacities of the IDF-IONPs increased when the IONPs were synthesized in more <span class="hlt">oxidizing</span> conditions. The fully <span class="hlt">oxidized</span> IDF-IONPs, maghemite (?-Fe2O3), showed the highest As(V) adsorption capacity, comparable to that of magnetite nanocrystals synthesized by thermal decomposition of <span class="hlt">iron</span> pentacarbonyl and equivalent to three to four times higher capacity than that of a commonly used goethite-based adsorbent. All IONPs were magnetically responsive, which is of great importance for solid?liquid separation. This study demonstrates that the IONPs synthesized in gas-phase flame, particularly IDF-IONPs, are excellent adsorbents because of their high As(V) sorption capacity, potential for large-scale production, and useful magnetic property.</p> <div class="credits"> <p class="dwt_author">Abid, Aamir D.; Kanematsu, Masakazu; Young, Thomas M.; Kennedy, Ian M.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">386</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/6525349"> <span id="translatedtitle">Oxygen on <span class="hlt">iron</span> <span class="hlt">oxide</span>: effect on the selective <span class="hlt">oxidation</span> of butane</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">The effect of preadsorbed and gas phase oxygen on the selective <span class="hlt">oxidation</span> of butene to butadiene on ..cap alpha..-<span class="hlt">iron</span> <span class="hlt">oxide</span> was investigated using adsorption-desorption and pulse reaction technique. It was found that irreversibly adsorbed oxygen did not affect the butene <span class="hlt">oxidation</span> reaction. However, the presence of gas phase oxygen significantly reduced the production of butadiene and increased the production of carbon dioxide. This decrease in butadiene production was due to the high reactivity of adsorbed butadiene precursors toward weakly adsorbed oxygen. However, these butadiene precursors were not reactive toward nitrous <span class="hlt">oxide</span>. Therefore, under steady-state conditions, the rate of production of butadiene is determined by the competition between the desorption of butadiene and the degradation of the precursors by oxygen.</p> <div class="credits"> <p class="dwt_author">Yang, B.L.; Kung, H.H.</p> <p class="dwt_publisher"></p> <p class="publishDate">1982-10-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">387</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/23237516"> <span id="translatedtitle">Superparamagnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticle targeting of MSCs in vascular injury.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Vascular occlusion can result in fatal myocardial infarction, stroke or loss of limb in peripheral arterial disease. Interventional balloon angioplasty is a common first line procedure for vascular disease treatment, but long term success is limited by restenosis and neointimal hyperplasia. Cellular therapies have been proposed to mitigate these issues; however efficacy is low, in part due to poor cell retention. We show that magnetic targeting of mesenchymal stem cells gives rise to a 6-fold increase in cell retention following balloon angioplasty in a rabbit model using a clinically applicable permanent magnet. Cells labelled with superparamagnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles exhibit no negative effects on cell viability, differentiation or secretion patterns. The increase in stem cell retention leads to a reduction in restenosis three weeks after cell delivery. PMID:23237516</p> <div class="credits"> <p class="dwt_author">Riegler, Johannes; Liew, Aaron; Hynes, Sean O; Ortega, Daniel; O'Brien, Timothy; Day, Richard M; Richards, Toby; Sharif, Faisal; Pankhurst, Quentin A; Lythgoe, Mark F</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-03-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">388</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2005Prama..65..855B"> <span id="translatedtitle"><span class="hlt">Iron</span> <span class="hlt">oxide</span> nanoparticles stabilized inside highly ordered mesoporous silica</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Nanosized <span class="hlt">iron</span> <span class="hlt">oxide</span>, a moderately large band-gap semiconductor and an essential component of optoelectrical and magnetic devices, has been prepared successfully inside the restricted internal pores of mesoporous silica material through in-situ reduction during impregnation. The samples were characterized by powder XRD, TEM, SEM/EDS, N_{2} adsorption, FT-IR and UV-visible spectroscopies. Characterization data indicated well-dispersed isolated nanoclusters of (Fe_{2}O_{3})_{n}, within the internal surface of 2D-hexagonal mesoporous silica structure. No occluded Fe/Fe_{2}O_{3} crystallites were observed at the external surface of the mesoporous silica nanocomposites. Inorganic mesoporous host, such as hydrophilic silica in the pore walls, directs a physical constraint necessary to prevent the creation of large Fe_{2}O_{3} agglomerates and enables the formation of nanosized Fe_{2}O_{3} particles inside the mesopore.</p> <div class="credits"> <p class="dwt_author">Bhaumik, A.; Samanta, S.; Mal, N. K.</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-11-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">389</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=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> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">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> <div class="credits"> <p class="dwt_author">Baker, A.C.; Keran, V.P.</p> <p class="dwt_publisher"></p> <p class="publishDate">1983-03-08</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">390</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014SPIE.8955E..1PT"> <span id="translatedtitle"><span class="hlt">Iron</span> <span class="hlt">oxide</span> nanoparticles in different modifications for antimicrobial phototherapy</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">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> <div class="credits"> <p class="dwt_author">Tuchina, Elena S.; Kozina, Kristina V.; Shelest, Nikita A.; Kochubey, Vyacheslav I.; Tuchin, Valery V.</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-03-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">391</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013JPhCS.441a2034I"> <span id="translatedtitle">Fabrication of <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles using laser ablation in liquids</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Nanoparticles of <span class="hlt">iron</span> <span class="hlt">oxides</span> were synthesized through the ablation of the bulk-targets of Fe, Fe3O4, and Fe2O3 in water by the irradiation of a Nd:YAG laser. Our samples prepared via the laser ablation method displayed small (ca. 1 nm in diameter) and large (over 5 nm in diameter) particles. The small particles were well-dispersed, whereas large particles were agglomerated. The FeO and Fe3O4 phases were formed in the synthesized powders irrespective of the kind of targets. The formation of the other phases, Fe and Fe2O3, changed depending on the the kind of targets used in the laser ablation. Poly(N-vinyl-2-pyrrolidone) (PVP) as a protective reagent was employed to disperse large particles in our samples, and accordingly, their dispersibility was improved as mole concentration of PVP increased.</p> <div class="credits"> <p class="dwt_author">Iwamoto, T.; Ishigaki, T.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-06-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">392</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2626938"> <span id="translatedtitle">Targeted magnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles for tumor imaging and therapy</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Magnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> (IO) nanoparticles with a long blood retention time, biodegradability and low toxicity have emerged as one of the primary nanomaterials for biomedical applications in vitro and in vivo. IO nanoparticles have a large surface area and can be engineered to provide a large number of functional groups for cross-linking to tumor-targeting ligands such as monoclonal antibodies, peptides, or small molecules for diagnostic imaging or delivery of therapeutic agents. IO nanoparticles possess unique paramagnetic properties, which and generate significant susceptibility effects resulting in strong T2 and T2* contrast, as well as T1 effects at very low concentrations for magnetic resonance imaging (MRI), which is widely used for clinical oncology imaging. We review recent advances in the development of targeted IO nanoparticles for tumor imaging and therapy.</p> <div class="credits"> <p class="dwt_author">Peng, Xiang-Hong; Qian, Ximei; Mao, Hui; Wang, Andrew Y; Chen, Zhuo (Georgia); Nie, Shuming; Shin, Dong M</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">393</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/5570873"> <span id="translatedtitle">Electron transfer to <span class="hlt">iron</span>(III) <span class="hlt">oxide</span> colloids</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">The electron transfer reaction from viologen radicals to colloidal <span class="hlt">iron</span>(III) <span class="hlt">oxide</span> and oxyhydroxide particles was investigated by pulse and steady-state radiolysis techniques. The rate of electron injection to oxyhydroxide particles was clearly controlled by their surface charge and in the region near the isoelectric point, the electron transfer rate is slower than the diffusion-controlled rate by at least two orders of magnitude. Conductivity measurements clearly reveal the occurrence of protonation reactions immediately following the initial electron transfer step. On the basis of the experimentally measured ratio of protons consumed to electrons injected, a mechanistic pathway describing the sequence of protonation reactions is proposed. The competition between surface trapping of charge and the migration of charge into the interior of the particles and the factors controlling these two events are also discussed. 17 refs., 3 figs.</p> <div class="credits"> <p class="dwt_author">Mulvaney, P.; Grieser, F.; Swayambunathan, V.; Meisel, D.</p> <p class="dwt_publisher"></p> <p class="publishDate">1987-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">394</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/43181542"> <span id="translatedtitle">Ultrastructural Study of <span class="hlt">Iron</span> <span class="hlt">Oxide</span> Precipitates: Implications for the Search for Biosignatures in the Meridiani Hematite Concretions, Mars</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Two terrestrial environments that have been proposed as analogs for the <span class="hlt">iron</span> <span class="hlt">oxide</span> precipitation in the Meridiani Planum region of Mars include the Rio Tinto precipitates and southern Utah marble concretions. Samples of two typical Utah <span class="hlt">iron</span> <span class="hlt">oxide</span> concretions and <span class="hlt">iron</span> <span class="hlt">oxide</span> precipitates in contact with biofilms from Rio Tinto have been studied to determine whether evidence could be found</p> <div class="credits"> <p class="dwt_author">Virginia Souza-Egipsy; Jens Ormö; Brenda Beitler Bowen; Marjorie A. Chan; Goro Komatsu</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">395</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/40541863"> <span id="translatedtitle">In situ synthesis and magnetic studies of <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles in calcium-alginate matrix for biomedical applications</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">In this work we applied a new route to synthesize magnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles into alginate polymer for future application as drug delivery system activated by magnetic external stimuli. Calcium-alginate was used to encapsulate <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles, and as scaffold for particle nucleation and its influence on particles size and magnetic properties were studied. The <span class="hlt">iron</span> <span class="hlt">oxide</span> mean sizes were</p> <div class="credits"> <p class="dwt_author">M. A. Morales; P. V. Finotelli; J. A. H. Coaquira; M. H. M. Rocha-Leão; C. Diaz-Aguila; E. M. Baggio-Saitovitch; A. M Rossi</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">396</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=203127"> <span id="translatedtitle">Synergistic Competitive Inhibition of Ferrous <span class="hlt">Iron</span> <span class="hlt">Oxidation</span> by Thiobacillus ferrooxidans by Increasing Concentrations of Ferric <span class="hlt">Iron</span> and Cells</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary"><span class="hlt">Oxidation</span> of ferrous <span class="hlt">iron</span> by Thiobacillus ferrooxidans SM-4 was inhibited competitively by increasing concentrations of ferric <span class="hlt">iron</span> or cells. A kinetic analysis showed that binding of one inhibitor did not exclude binding of the other and led to synergistic inhibition by the two inhibitors. Binding of one inhibitor, however, was affected by the other inhibitor, and the apparent inhibition constant increased with increasing concentrations of the other inhibitor.</p> <div class="credits"> <p class="dwt_author">Lizama, Hector M.; Suzuki, Isamu</p> <p class="dwt_publisher"></p> <p class="publishDate">1989-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">397</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/40531300"> <span id="translatedtitle">Synthesis of nanocrystalline <span class="hlt">iron</span> <span class="hlt">oxide</span> ultrathin films by thermal decomposition of <span class="hlt">iron</span> nitropruside: Structural and optical properties</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Ultrathin films of nanocrystalline ?-Fe2O3 have been deposited on glass substrates from an inorganic precursor, <span class="hlt">iron</span> nitropruside. This is a novel route of synthesis for <span class="hlt">iron</span> <span class="hlt">oxide</span> thin films on glass substrates, by annealing the precursor thin film in air at 650°C for 15min. The films were characterized using TG–DTA analysis, X-ray diffraction, UV–visible, FESEM, AFM and Raman measurements. X-ray</p> <div class="credits"> <p class="dwt_author">Sanjib Kumar Bhar; Nillohit Mukherjee; Swarup Kumar Maji; Bibhutosh Adhikary; Anup Mondal</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">398</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/21711036"> <span id="translatedtitle">Adsorption of fatty acids on <span class="hlt">iron</span> (hydr)<span class="hlt">oxides</span> from aqueous solutions.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">The interaction of <span class="hlt">iron</span> (hydr)<span class="hlt">oxides</span> with fatty acids is related to many industrial and natural processes. To resolve current controversies about the adsorption configurations of fatty acids and the conditions of the maximum hydrophobicity of the minerals, we perform a detailed study of the adsorption of sodium laurate (dodecanoate) on 150 nm hematite (?-Fe(2)O(3)) particles as a model system. The methods used include in situ FTIR spectroscopy, ex situ X-ray photoelectron spectroscopy (XPS), measurements of the adsorption isotherm and contact angle, as well as the density functional theory (DFT) calculations. We found that the laurate adlayer is present as a mixture of inner-sphere monodentate mononuclear (ISMM) and outer-sphere (OS) <span class="hlt">hydration</span> shared complexes independent of the solution pH. Protonation of the OS complexes does not influence the conformational order of the surfactant tails. One monolayer, which is filled through the growth of domains and is reached at the micellization/precipitation edge of laurate, makes the particles superhydrophobic. These results contradict previous models of the fatty acid adsorption and suggest new interpretation of literature data. Finally, we discovered that the fractions of both the OS laurate and its molecular form increase in D(2)O, which can be used for interpreting complex spectra. We discuss shortcomings of vibrational spectroscopy in determining the interfacial coordination of carboxylate groups. This work advances the current understanding of the <span class="hlt">oxide</span>-carboxylate interactions and the research toward improving performance of fatty acids as surfactants, dispersants, lubricants, and anticorrosion reagents. PMID:21711036</p> <div class="credits"> <p class="dwt_author">Chernyshova, Irina V; Ponnurangam, Sathish; Somasundaran, Ponisseril</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-08-16</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">399</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=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> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">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> <div class="credits"> <p class="dwt_author">Onysko, S.J.</p> <p class="dwt_publisher"></p> <p class="publishDate">1984-07-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">400</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1988EnGeo..11..289S"> <span id="translatedtitle"><span class="hlt">Iron</span> sulfide <span class="hlt">oxidation</span> and the chemistry of acid generation</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">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 (AI), <span class="hlt">iron</span> (Fe), and sulfate (SO4) 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 percent pyrite) and a Chattanooga Shale (1.5 percent pyrite). 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 Fe3+, Fe2+, Al3+, and SO4 2- 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 Fe3+ and Fe2+ activities appeared to be controlled by amorphous Fe(OH)3 solid phase above a pH of 6.0 and below pe+pH 11.0. The Fe3+, Fe2+, and SO4 2- activities reached saturation with respect to FeOHSO4 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, Fe2+, Fe3+, and SO4 2- activities are supported by FeSO4·7H2O solid phase. Above a pH of 6.0, the Al3+ activity showed an equilibrium with amorphous Al(OH)3 solid phase. Below pH 6.0, Al3+ and SO4 2- activities are regulated by the AlOHSO4 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. As a result, the long-term chemistry associated with disposal environments can be largely predicted (including trace elements).</p> <div class="credits"> <p class="dwt_author">Sullivan, Patrick J.; Yelton, Jennifer L.; Reddy, K. J.</p> <p class="dwt_publisher"></p> <p class="publishDate">1988-06-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_19");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return showDiv("page_4");' 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onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">401</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=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> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">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> <div class="credits"> <p class="dwt_author">Kaur, Maninder; McCloy, John S.; Qiang, You</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-04-03</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">402</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3010160"> <span id="translatedtitle">Concentration-dependent toxicity of <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles mediated by increased <span class="hlt">oxidative</span> stress</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary"><span class="hlt">Iron</span> <span class="hlt">oxide</span> nanoparticles with unique magnetic properties have a high potential for use in several biomedical, bioengineering and in vivo applications, including tissue repair, magnetic resonance imaging, immunoassay, drug delivery, detoxification of biologic fluids, cell sorting, and hyperthermia. Although various surface modifications are being done for making these nonbiodegradable nanoparticles more biocompatible, their toxic potential is still a major concern. The current in vitro study of the interaction of superparamagnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles of mean diameter 30 nm coated with Tween 80 and murine macrophage (J774) cells was undertaken to evaluate the dose- and time-dependent toxic potential, as well as investigate the role of <span class="hlt">oxidative</span> stress in the toxicity. A 15–30 nm size range of spherical nanoparticles were characterized by transmission electron microscopy and zeta sizer. MTT assay showed >95% viability of cells in lower concentrations (25–200 ?g/mL) and up to three hours of exposure, whereas at higher concentrations (300–500 ?g/mL) and prolonged (six hours) exposure viability reduced to 55%–65%. Necrosis-apoptosis assay by propidium iodide and Hoechst-33342 staining revealed loss of the majority of the cells by apoptosis. H2DCFDDA assay to quantify generation of intracellular reactive oxygen species (ROS) indicated that exposure to a higher concentration of nanoparticles resulted in enhanced ROS generation, leading to cell injury and death. The cell membrane injury induced by nanoparticles studied using the lactate dehydrogenase assay, showed both concentration- and time-dependent damage. Thus, this study concluded that use of a low optimum concentration of superparamagnetic <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles is important for avoidance of <span class="hlt">oxidative</span> stress-induced cell injury and death.</p> <div class="credits"> <p class="dwt_author">Naqvi, Saba; Samim, Mohammad; Abdin, MZ; Ahmed, Farhan Jalees; Maitra, AN; Prashant, CK; Dinda, Amit K</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">403</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/26326786"> <span id="translatedtitle">Activated carbon\\/<span class="hlt">iron</span> <span class="hlt">oxide</span> composites for the removal of atrazine from aqueous medium</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The adsorption features of activated carbon and the <span class="hlt">oxidation</span> properties of <span class="hlt">iron</span> <span class="hlt">oxides</span> were combined in a composite to produce new materials for atrazine removal from aqueous medium. Activated carbon\\/<span class="hlt">iron</span> <span class="hlt">oxide</span> composites were prepared at 1\\/1 and 5\\/1 mass ratios and characterized with powder X-ray diffractometry (XRD), infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and nitrogen adsorption measurements. The adsorption</p> <div class="credits"> <p class="dwt_author">Cínthia S. Castro; Mário C. Guerreiro; Maraísa Gonçalves; Luiz C. A. Oliveira; Alexandre S. Anastácio</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">404</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/48527493"> <span id="translatedtitle">Review of the High-Temperature <span class="hlt">Oxidation</span> of <span class="hlt">Iron</span> and Carbon Steels in Air or Oxygen</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">This paper reviews previous studies on <span class="hlt">iron</span> and steel <span class="hlt">oxidation</span> in oxygen or air at high temperatures. <span class="hlt">Oxidation</span> of <span class="hlt">iron</span> at temperatures above 700°C follows the parabolic law with the development of a three-layered hematite\\/magnetite\\/wüstite scale structure. However, at temperatures below 700°C, inconsistent results have been reported, and the scale structures are less regular, significantly affected by sample-preparation methods. <span class="hlt">Oxidation</span></p> <div class="credits"> <p class="dwt_author">R. Y. Chen; W. Y. D. Yeun</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">405</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://faculty.eas.ualberta.ca/konhauser/Geology%282005%29.pdf"> <span id="translatedtitle">Deposition of banded <span class="hlt">iron</span> formations by anoxygenic phototrophic Fe(II)-<span class="hlt">oxidizing</span> bacteria</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The mechanism of banded <span class="hlt">iron</span> formation (BIF) deposition is controversial, but classically has been interpreted to reflect ferrous <span class="hlt">iron</span> (Fe(II)) <span class="hlt">oxidation</span> by molecular oxygen after cyanobacteria evolved on Earth. Anoxygenic photoautotrophic bacteria can also catalyze Fe(II) <span class="hlt">oxidation</span> under anoxic conditions. Calculations based on experimentally determined Fe(II) <span class="hlt">oxidation</span> rates by these organisms under light regimes representative of ocean water at depths</p> <div class="credits"> <p class="dwt_author">Andreas Kappler; Claudia Pasquero; Kurt O. Konhauser; Dianne K. Newman</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">406</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/47857848"> <span id="translatedtitle">Phase-controlled preparation of <span class="hlt">iron</span> (oxyhydr)<span class="hlt">oxide</span> nanocrystallines for heavy metal removal</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Obtaining cost-effective <span class="hlt">iron</span> (oxyhydr)<span class="hlt">oxide</span> nanocrystallines is the essential prerequisite for their future extensive applications\\u000a in environmental remediation, such as the removal of heavy metals from contaminated waters. Here, various phases of <span class="hlt">iron</span> (oxyhydr)<span class="hlt">oxide</span>\\u000a nanocrystallines were simply synthesized from the phase-controlled transformation of amorphous hydrous ferric- or ferrous-<span class="hlt">oxide</span>\\u000a in thermal solution with a certain ethanol\\/water ratio and with the presence of</p> <div class="credits"> <p class="dwt_author">Xiongye Zhao; Xuejun Guo; Zhifeng Yang; Hong Liu; Qingqing Qian</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">407</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/52153180"> <span id="translatedtitle">A New Method of Preparation of Magnetite Nanoparticles from <span class="hlt">Iron</span> <span class="hlt">Oxide</span> Hydroxide</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">There are only two basic ways to produce magnetite at low temperature: by partial <span class="hlt">oxidation</span> of a FeII salt solution with <span class="hlt">oxidant</span> under alkaline condition and by precipitation of a mixed FeII\\/FeIII solution. At high temperature, the method involves reduction of <span class="hlt">iron</span> <span class="hlt">oxide</span> by a suitable reductant. Here we propose a new method of preparation of nanoparticle Fe3O4 from <span class="hlt">iron</span></p> <div class="credits"> <p class="dwt_author">S. A. Kahani; M. Jafari</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">408</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/60702244"> <span id="translatedtitle">Trace element cycling through <span class="hlt">iron</span> <span class="hlt">oxide</span> minerals during redox-driven dynamic recrystallization</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Microbially driven <span class="hlt">iron</span> redox cycling in soil and sedimentary systems, including during diagenesis and fluid migration, may activate secondary abiotic reactions between aqueous Fe(II) and solid Fe(III) <span class="hlt">oxides</span>. These reactions catalyze dynamic recrystallization of <span class="hlt">iron</span> <span class="hlt">oxide</span> minerals through localized and simultaneous <span class="hlt">oxidative</span> adsorption of Fe(II) and reductive dissolution of Fe(III). Redox-active trace elements undergo speciation changes during this process, but</p> <div class="credits"> <p class="dwt_author">Andrew J. Frierdich; Yun Luo; Jeffrey G. Catalano</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">409</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ias.ac.in/matersci/bmsoct2008/759.pdf"> <span id="translatedtitle">Strain induced anomalous red shift in mesoscopic <span class="hlt">iron</span> <span class="hlt">oxide</span> prepared by a novel technique</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Nano magnetic <span class="hlt">oxides</span> are promising candidates for high density magnetic storage and other applications. Nonspherical mesoscopic\\u000a <span class="hlt">iron</span> <span class="hlt">oxide</span> particles are also candidate materials for studying the shape, size and strain induced modifications of various\\u000a physical properties viz. optical, magnetic and structural. Spherical and nonspherical <span class="hlt">iron</span> <span class="hlt">oxides</span> having an aspect ratio,\\u000a ?2, are synthesized by employing starch and ethylene glycol and</p> <div class="credits"> <p class="dwt_author">T. N. Narayanan; D. Sakthi Kumar; Yasuhiko Yoshida; M. R. Anantharaman</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">410</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3049993"> <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> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">In the absence of base, the reaction of [FeII(TMCS)]PF6 (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, [FeIV(O)(TMCS)]PF6), as previously observed in the presence of strong base (KOtBu). Instead, the addition of one equivalent 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 Mössbauer spectroscopies. ESI-MS showed 3 to be formulated as [FeII(TMCS) + 2O]+), while EXAFS analysis suggested that 3 was an O-bound <span class="hlt">iron</span>(II)-sulfinate complex (Fe–O = 1.95 Å, Fe–S = 3.26 Å). 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. Mössbauer spectroscopy confirmed 4 to be a novel <span class="hlt">iron</span>(IV) compound, different from 2, and EXAFS (Fe=O = 1.64 Å) and resonance Raman (?Fe=O = 834 cm?1) showed that indeed an oxoiron(IV) unit had been generated in 4. Furthermore, both infra-red and Raman spectroscopy gave indications that 4 contains a metal-bound sulfinate moiety (?s(SO2) = ~ 1000 cm ?1, ?as(SO2) = ~ 1150 cm ?1). Investigations into the reactivity of 1 and 2 towards H+ 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> <div class="credits"> <p class="dwt_author">McDonald, Aidan R.; Bukowski, Michael R.; Farquhar, Erik R.; Jackson, Timothy A.; Koehntop, Kevin D.; Seo, Mi Sook; De Hont, Raymond F.; Stubna, Audria; Halfen, Jason A.; Munck, Eckard; Nam, Wonwoo; Que, Lawrence</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">411</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/9696702"> <span id="translatedtitle">The labile <span class="hlt">iron</span> pool in hepatocytes: prooxidant-induced increase in free <span class="hlt">iron</span> precedes <span class="hlt">oxidative</span> cell injury.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">The labile <span class="hlt">iron</span> pool (LIP) represents the nonferritin-bound, redox-active <span class="hlt">iron</span> that has been implicated in <span class="hlt">oxidative</span> stress and cell injury. Here we examined whether alterations in LIP can be detected in cultured murine hepatocytes and whether increases in LIP are related to the <span class="hlt">oxidative</span> damage inflicted by the redox cycling drug nitrofurantoin (NFT). Early changes in LIP were monitored with the metal-sensitive fluorescent probe calcein (CA), the fluorescence of which is quenched on binding to <span class="hlt">iron</span>. Short-term exposure (<1 h) to NFT reduced the CA fluorescence signal by 30%, indicating that the amount of LIP-associated <span class="hlt">iron</span> had increased. Prolonged exposure (2 h) to NFT caused <span class="hlt">oxidative</span> cell injury. The addition of the cell-permeable ferrous <span class="hlt">iron</span> chelator 2,2'-bipyridyl not only prevented the quenching of CA fluorescence but also partially protected from NFT toxicity. It is concluded that reductive stress-induced increase in LIP is an essential event that precedes <span class="hlt">oxidative</span> cell damage in intact hepatocytes. PMID:9696702</p> <div class="credits"> <p class="dwt_author">Stäubli, A; Boelsterli, U A</p> <p class="dwt_publisher"></p> <p class="publishDate">1998-06-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">412</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/52005320"> <span id="translatedtitle">Characterization of <span class="hlt">Iron</span> <span class="hlt">Oxides</span> Commonly Formed as Corrosion Products on Steel</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">For fundamental studies of the atmospheric corrosion of steel, it is useful to identify the <span class="hlt">iron</span> <span class="hlt">oxide</span> phases present in rust layers. The nine <span class="hlt">iron</span> <span class="hlt">oxide</span> phases, <span class="hlt">iron</span> hydroxide (Fe(OH)2), <span class="hlt">iron</span> trihydroxide (Fe(OH)3), goethite (alpha-FeOOH), akaganeite (beta-FeOOH), lepidocrocite (gamma-FeOOH), feroxyhite (delta-FeOOH), hematite (alpha-Fe2O3), maghemite (gamma-Fe2O3) and magnetite (Fe3O4) are among those which have been reported to be present in the</p> <div class="credits"> <p class="dwt_author">Sei J. Oh; D. C. Cook; H. E. Townsend</p> <p class="dwt_publisher"></p> <p class="publishDate">1998-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">413</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/48774673"> <span id="translatedtitle">Characterization of <span class="hlt">Iron</span> <span class="hlt">Oxides</span> Commonly Formed as Corrosion Products on Steel</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">For fundamental studies of the atmospheric corrosion of steel, it is useful to identify the <span class="hlt">iron</span> <span class="hlt">oxide</span> phases present in rust\\u000a layers. The nine <span class="hlt">iron</span> <span class="hlt">oxide</span> phases, <span class="hlt">iron</span> hydroxide (Fe(OH)2), <span class="hlt">iron</span> trihydroxide (Fe(OH)3), goethite (?-FeOOH), akaganeite (?-FeOOH), lepidocrocite (?-FeOOH), feroxyhite (?-FeOOH), hematite (?-Fe2O3), maghemite (?-Fe2O3) and magnetite (Fe3O4) are among those which have been reported to be present in the</p> <div class="credits"> <p class="dwt_author">Sei J. Oh; D. C. Cook; H. E. Townsend</p> <p class="dwt_publisher"></p> <p class="publishDate">1998-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">414</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/24577924"> <span id="translatedtitle">Exploiting the interaction of polymethacrylates with <span class="hlt">iron</span> <span class="hlt">oxide</span> for the enhancement of mucoadhesive strength.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">The present investigation was aimed at preparation of polymethacrylate(s)- <span class="hlt">iron</span> <span class="hlt">oxide</span> conjugates and to evaluate mucoadhesive performance using texture analyzer. Eudragit RL-<span class="hlt">iron</span> <span class="hlt">oxide</span> or Eudragit RS-<span class="hlt">iron</span> <span class="hlt">oxide</span> conjugate granules were prepared by solvent evaporation technique. The mucoadhesive strength of pure Eudragit RL and RS was found to be 11.25±2.02 and 7.78±0.92 g respectively, whereas the same was found to be 36.42±4.01 and 24.32±4.44 for the <span class="hlt">iron</span> <span class="hlt">oxide</span> conjugates of Eudragit RL and RS respectively. Hence, mucoadhesive strength of polymethacrylates was found to be enhanced by this technique while, retaining their pH resistant property. A correlation (p>0.05) of 0.97 between mucoadhesive strength and zeta potential indicated conjugation of <span class="hlt">iron</span> <span class="hlt">oxide</span> contributed positive surface charge that causes enhancement of mucoadhesion. Further, the ATR-FTIR spectral analysis as well as DSC analysis supported existence of ionic interactions between conjugates (Eudragit RS or RL with <span class="hlt">iron</span> <span class="hlt">oxide</span>) and the tissue surface. Hence, the findings point out toward the expected potential use and application of Eudragit RL-<span class="hlt">iron</span> <span class="hlt">oxide</span> conjugate in mucoadhesive drug delivery systems, gastro retentive drug delivery systems, etc. PMID:24577924</p> <div class="credits"> <p class="dwt_author">Singh, Inderbir; Rana, Vikas</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-03-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">415</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/22587679"> <span id="translatedtitle"><span class="hlt">Iron</span> <span class="hlt">oxide</span>/hydroxide nanoparticles with negatively charged shells show increased uptake in Caco-2 cells.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">The absorption of commonly used ferrous <span class="hlt">iron</span> salts from intestinal segments at neutral to slightly alkaline pH is low, mainly because soluble ferrous <span class="hlt">iron</span> is easily <span class="hlt">oxidized</span> to poorly soluble ferric <span class="hlt">iron</span> and because ferrous <span class="hlt">iron</span>, but not ferric <span class="hlt">iron</span>, is carried by the divalent metal transporter DMT-1. Moreover, ferrous <span class="hlt">iron</span> frequently causes gastrointestinal side effects. <span class="hlt">Iron</span> hydroxide nanoparticles with neutral and hydrophilic carbohydrate shells are alternatively used to ferrous salts. In these formulations gastrointestinal side effects are rare because hundreds of ferric <span class="hlt">iron</span> atoms are safely packed in nanoscaled cores surrounded by the solubilizing shell; nevertheless, <span class="hlt">iron</span> bioavailability is even worse compared to ferrous salts. In this study the cell uptake of <span class="hlt">iron</span> hydroxide and <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles (FeONP) with negatively charged shells of different chemical types and sizes was compared to the uptake of those with neutral hydrophilic shells, ferrous sulfate and ferric chloride. The nanoparticle uptake was measured in Caco-2 cells with the <span class="hlt">iron</span> detecting ferrozine method and visualized by transmission electron microscopy. The toxicity was evaluated using the MTT assay. For nanoparticles with a negatively charged shell the <span class="hlt">iron</span> uptake was about 40 times higher compared to those with neutral hydrophilic carbohydrate shell or ferric chloride and in the same range as ferrous sulfate. However, in contrast to ferrous sulfate, nanoparticles with negatively charged shells showed no toxicity. Two different uptake mechanisms were proposed: diffusion for hydroxide nanoparticles with neutral hydrophilic shell and adsorptive endocytosis for nanoparticles with negatively charged shells. It needs to be determined whether <span class="hlt">iron</span> hydroxide nanoparticles with negatively charged shells also show improved bioavailability in <span class="hlt">iron</span>-deficient patients compared to <span class="hlt">iron</span> hydroxide nanoparticles with a neutral hydrophilic shell, which exist in the market today. PMID:22587679</p> <div class="credits"> <p class="dwt_author">Jahn, Markus R; Nawroth, Thomas; Fütterer, Sören; Wolfrum, Uwe; Kolb, Ute; Langguth, Peter</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-06-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">416</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://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> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">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. PMID:24784347</p> <div class="credits"> <p class="dwt_author">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 class="dwt_publisher"></p> <p class="publishDate">2014-05-27</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">417</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/11666301"> <span id="translatedtitle">Disproportionation of <span class="hlt">Iron</span>(III) Porphyrin pi-Cation Radicals in the Presence of Sterically Hindered Pyridines. Spectroscopic Detection of Asymmetric Highly <span class="hlt">Oxidized</span> Intermediates.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">The reactivity of <span class="hlt">iron</span>(III) tetraphenylporphyrin pi-cation radical (TPP(*))Fe(III)(ClO(4))(2), (1-1) <span class="hlt">iron</span>(III) tetra-p-tolylporphyrin pi-cation radical (TTP(*))Fe(III)(ClO(4))(2) (1-2) and <span class="hlt">iron</span>(III) tetramesitylporphyrin pi-cation radical (TMP(*))Fe(III)(ClO(4))(2) (1-3) complexes with 2,4,6-collidine, 2,3,6-collidine, 2-picoline, 2,6-di-tert-butylpyridine, and 2,6-dibromopyridine has been examined by (1)H NMR spectroscopy in dichloromethane-d(2) solution at low temperatures. These complexes undergo <span class="hlt">hydration</span> processes which are essential in the generation of highly <span class="hlt">oxidized</span> species via acid base/equilibria of coordinated water followed by disproportionation pathway, giving as sole stable products [(TPP(*))Fe(III)OFe(III)(TPP)](+) (4-1), [(TTP(*))Fe(III)OFe(III)(TTP)](+) (4-2), and (TMP)Fe(III)(OH) (6) respectively. The sterically hindered pyridines act as efficient proton scavengers. Two novel highly <span class="hlt">oxidized</span> <span class="hlt">iron</span> complexes have been detected by (1)H NMR spectroscopy after addition of 2,4,6-collidine to (TTP(*))Fe(III)(ClO(4))(2) or (TPP(*))Fe(III)(ClO(4))(2) in dichloromethane-d(2) solution at 202 K. New intermediates have been identified as <span class="hlt">iron</span> porphyrin N-<span class="hlt">oxide</span> complexes, i.e., <span class="hlt">iron</span>(III) porphyrin N-<span class="hlt">oxide</span> cation radical (2-n) and <span class="hlt">iron</span>(IV) porphyrin N-<span class="hlt">oxide</span> radical (3-n). The (1)H NMR results indicate that the D(4)(h)() symmetry of the parent <span class="hlt">iron</span>(III) pi-cation radical is drastically reduced upon disproportionation in the presence of proton scavengers. Both species are very unstable and were observed from 176 to 232 K. The intermediate 2-2 has a (1)H NMR spectrum which demonstrates large hyperfine shifts (ppm) for the meso p-tolyl substituents (ortho 98.0, 94.8, 92.9, 91.7; meta -34.8, -38.7, -41.5, -42.3; p-CH(3) -86.3, -88.0) which are consistent with presence of an N-substituted <span class="hlt">iron</span> porphyrin radical in the product mixture. The characteristic (1)H NMR spectrum of 2-2 includes six pyrrole resonances at 149.6, 118.2, 115.4, 88.3, 64.6, and 55.7 ppm at 202 K, i.e., in the positions corresponding to <span class="hlt">iron</span>(III) high-spin porphyrins. On warming to 222 K, the pyrrole resonances broaden and then coalesce pairwaise. Such dynamic behavior is accounted for by a rearrangement mechanism which involves an inversion of the porphyrin puckering. The pattern of p-tolyl resonances revealed the cation radical electronic structure of 3-2. The p-tolyl resonances are divided in two distinct sets showing opposite direction of the isotropic shift for the same ring positions. The pyrrole resonances of 3-2 also demonstrated downfield and upfield shifts. A disproportionation mechanism of the <span class="hlt">hydrated</span> <span class="hlt">iron</span> porphyrin cation radicals to generate 2 and 3 has been proposed. Both intermediates react with triphenylphosphine to produce triphenylphosphine <span class="hlt">oxide</span> and high-spin <span class="hlt">iron</span> porphyrins. Addition of 2,4,6-collidine to (TMP(*))Fe(III)(ClO(4))(2) does not produce analogs of 2 and 3 found for sterically unprotected porphyrins. It results instead in the formation of a variety of X(TMP(*))Fe(IV)O (5) complexes also accounted for by the disproportionation process. PMID:11666301</p> <div class="credits"> <p class="dwt_author">Rachlewicz, Krystyna; Latos-Grazynski, Lechoslaw</p> <p class="dwt_publisher"></p> <p class="publishDate">1996-02-28</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">418</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1137755"> <span id="translatedtitle">Defining the roles of the threefold channels in <span class="hlt">iron</span> uptake, <span class="hlt">iron</span> <span class="hlt">oxidation</span> and <span class="hlt">iron</span>-core formation in ferritin: a study aided by site-directed mutagenesis.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">This paper aims to define the role of the threefold intersubunit channels in <span class="hlt">iron</span> uptake and sequestration processes in the <span class="hlt">iron</span>-storage protein, ferritin. <span class="hlt">Iron</span> uptake, measured as loss of availability of Fe(II) to ferrozine (due to <span class="hlt">oxidation</span>), has been studied in recombinant human H-chain ferritins bearing amino acid substitutions in the threefold channels or ferroxidase centres. Similar measurements with recombinant horse L-chain ferritin are compared. It is concluded that significant Fe(II) <span class="hlt">oxidation</span> occurs only at the H-chain ferroxidase centres and not in the threefold channels, although this route is used by Fe(II) for entry. Investigations by Mössbauer and u.v.-difference spectroscopy show that part of the <span class="hlt">iron</span> <span class="hlt">oxidized</span> by H-chain ferritin returns to the threefold channels as Fe(III). This monomeric Fe(III) can be displaced by addition of Tb(III). Fe(III) also moves into the cavity for formation of the <span class="hlt">iron</span>-core mineral, ferrihydrite. <span class="hlt">Iron</span> incorporated into ferrihydrite becomes kinetically inert. Images Figure 6</p> <div class="credits"> <p class="dwt_author">Treffry, A; Bauminger, E R; Hechel, D; Hodson, N W; Nowik, I; Yewdall, S J; Harrison, P M</p> <p class="dwt_publisher"></p> <p class="publishDate">1993-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">419</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/22820828"> <span id="translatedtitle">Reduction behavior of <span class="hlt">iron</span> <span class="hlt">oxides</span> in hydrogen and carbon monoxide atmospheres</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The reduction of various <span class="hlt">iron</span> <span class="hlt">oxides</span> in hydrogen and carbon monoxide atmospheres has been investigated by temperature programmed reduction (TPRH2 and TPRCO), thermo-gravimetric and differential temperature analysis (TG-DTA-MS), and conventional and “in situ” XRD methods. Five different compounds of <span class="hlt">iron</span> <span class="hlt">oxides</span> were characterized: hematite ?-Fe2O3, goethite ?-FeOOH, ferrihydrite Fe5HO8·4H2O, magnetite Fe3O4 and wüstite FeO. In the case of <span class="hlt">iron</span> <span class="hlt">oxide</span>-hydroxides,</p> <div class="credits"> <p class="dwt_author">W. K. Jozwiak; E. Kaczmarek; T. P. Maniecki; W. Ignaczak; W. Maniukiewicz</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">420</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/doepatents/biblio/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> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p class="result-summary">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> <div class="credits"> <p class="dwt_author">Khan, M. Rashid (Morgantown, WV)</p> <p class="dwt_publisher"></p> <p class="publishDate">1989-01-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_20");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return 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href="#">11</a> <a onClick='return showDiv("page_12");' href="#">12</a> <a onClick='return showDiv("page_13");' href="#">13</a> <a onClick='return showDiv("page_14");' href="#">14</a> <a onClick='return showDiv("page_15");' href="#">15</a> <a onClick='return showDiv("page_16");' href="#">16</a> <a onClick='return showDiv("page_17");' href="#">17</a> <a onClick='return showDiv("page_18");' href="#">18</a> <a onClick='return showDiv("page_19");' href="#">19</a> <a onClick='return showDiv("page_20");' href="#">20</a> <a onClick='return showDiv("page_21");' href="#">21</a> <a style="font-weight: bold;">22</a> <a onClick='return showDiv("page_23");' href="#">23</a> <a onClick='return showDiv("page_24");' href="#">24</a> <a onClick='return showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_23");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">421</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/doepatents/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> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p class="result-summary">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> <div class="credits"> <p class="dwt_author">Rashid Khan, M.</p> <p class="dwt_publisher"></p> <p class="publishDate">1988-05-05</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">422</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/585494"> <span id="translatedtitle">Physiochemical, mineralogical, and isotopic characterization of magnetite-rich <span class="hlt">iron</span> <span class="hlt">oxides</span> formed by thermophilic <span class="hlt">iron</span>-reducing bacteria</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Thermophilic (45-75{degrees}C) <span class="hlt">iron</span>-reducing bacteria obtained from two sedimentary basins in Virginia and Colorado, USA, reduced amorphous Fe(III) oxyhydroxide to form magnetite-rich (>60% in most samples) <span class="hlt">iron</span> <span class="hlt">oxides</span> in acetate- or H{sub 2}/CO{sub 2}-enriched cultures. The mineralogical compositions of the <span class="hlt">iron</span> <span class="hlt">oxides</span> were determined by X-ray diffraction and <span class="hlt">oxidation</span> state analyses. Significantly lower Eh values (< -300 mV) occurred in the enrichment cultures than in the abiotic controls (Eh > -100 mV). The pH values in acetate-enriched cultures did not change significantly from the starting value siderite was formed in addition to magnetite. The microbial production of magnetic and siderite was consistent, on a thermodynamic basis, with Eh-pH conditions determined for these experiments. Examination of the magnetite-rich <span class="hlt">iron</span> <span class="hlt">oxides</span> by scanning electron microscopy showed extracellular aggregates of <200 nm and no distinguishable increase in particle size over a period of 20 days. Average values of oxygen isotope fractionation between the magnetite-rich <span class="hlt">iron</span> <span class="hlt">oxides</span> (io) and water (wt), expressed as 10{sup 3} ln {alpha}{sub io-wt}, ranged from -0.09% at 50{degrees}C to -1.08{per_thousand} at 70{degrees}C. These values did not differ significantly among various cultures of different growth rates, suggesting that a kinetic isotopic effect is either unimportant or reproducible during microbial magnetic formation. Results of this research indicate that studies combining microbial activity, solution chemistry, mineralogy, and oxygen isotopes can provide insight into the environmental conditions and mechanisms for biogenic <span class="hlt">iron</span> mineral formation in natural systems. 62 refs., 6 figs., 3 tabs.</p> <div class="credits"> <p class="dwt_author">Zhang, Chuanlun; Liu, Shi; Phelps, T.J.; Elless, M. [Oak Ridge National Lab., TN (United States)] [and others] [Oak Ridge National Lab., TN (United States); and others</p> <p class="dwt_publisher"></p> <p class="publishDate">1997-11-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">423</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/21268642"> <span id="translatedtitle">A cast-mold approach to <span class="hlt">iron</span> <span class="hlt">oxide</span> and Pt/<span class="hlt">iron</span> <span class="hlt">oxide</span> nanocontainers and nanoparticles with a reactive concave surface.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">We report the synthesis of various <span class="hlt">iron</span> <span class="hlt">oxide</span> nanocontainers and Pt-<span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles based on a cast-mold approach, starting from nanoparticles having a metal core (either Au or AuPt) and an <span class="hlt">iron</span> <span class="hlt">oxide</span> shell. Upon annealing, the particles evolve to asymmetric core-shells and then to heterodimers. If iodine is used to leach Au out of these structures, asymmetric core-shells evolve into "nanocontainers", that is, <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticles enclosing a cavity accessible through nanometer-sized pores, while heterodimers evolve into particles with a concave region. When starting from a metal domain made of AuPt, selective leaching of the Au atoms yields the same <span class="hlt">iron</span> <span class="hlt">oxide</span> nanoparticle morphologies but now encasing Pt domains (in their concave region or in their cavity). We found that the concave nanoparticles are capable of destabilizing Au nanocrystals of sizes matching that of the concave region. In addition, for the nanocontainers, we propose two different applications: (i) we demonstrate loading of the cavity region of the nanocontainers with the antitumoral drug cis-platin; and (ii) we show that nanocontainers encasing Pt domains can act as recoverable photocatalysts for the reduction of a model dye. PMID:21268642</p> <div class="credits"> <p class="dwt_author">George, Chandramohan; Dorfs, Dirk; Bertoni, Giovanni; Falqui, Andrea; Genovese, Alessandro; Pellegrino, Teresa; Roig, Anna; Quarta, Alessandra; Comparelli, Roberto; Curri, M Lucia; Cingolani, Roberto; Manna, Liberato</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-02-23</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">424</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=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> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">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> <div class="credits"> <p class="dwt_author">Kupka, Daniel; Liljeqvist, Maria; Nurmi, Pauliina; Puhakka, Jaakko A; Tuovinen, Olli H; Dopson, Mark</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">425</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/23900290"> <span id="translatedtitle">X-ray excited-optical luminescence of lanthanides in phosphors prepared from yttrium <span class="hlt">oxide</span> and <span class="hlt">iron</span> transition-group <span class="hlt">oxides</span>: application to the determination of lanthanides in <span class="hlt">iron</span> and its alloys</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">A series of new phosphors was prepared using yttrium <span class="hlt">oxide</span> and the ; <span class="hlt">oxides</span> of the <span class="hlt">iron</span> transition group elements. These phosphors when excited by x-; ray radiation are strongly luminescent in the visible spectral region if the ; <span class="hlt">oxides</span> of the <span class="hlt">iron</span>-group <span class="hlt">oxides</span> contain lanthanide elements. These phosphors ; were used for the determination of several lanthanides at the</p> <div class="credits"> <p class="dwt_author">Edward L. DeKalb; Velmer A. Fassel</p> <p class="dwt_publisher"></p> <p class="publishDate">1975-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">426</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2007AcGeo..55..133P"> <span id="translatedtitle">Stability of <span class="hlt">iron</span> <span class="hlt">oxides</span> and their role in the formation of rock magnetism</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Thermodynamic conditions (first of all, temperature) are the main dynamic factors in the transformation process of ferrous to ferric <span class="hlt">iron</span> (TFFI). TFFI usually takes place within a temperature range of 473 843 K (most active at temperatures above 673 K) and does not require presence of the <span class="hlt">oxidizing</span> agents above 673 K. Analysis of the chemical composition of different rocks and minerals indicates that only for some sedimentary rocks is the relative content of ferrous <span class="hlt">iron</span> <span class="hlt">oxide</span> less than its value in magnetite, and this value is minimal for oceanic sediments. The relative content of ferrous <span class="hlt">iron</span> <span class="hlt">oxide</span> in oceanic magmatic rocks exceeds this value in continental magmatic rocks and depends on the rate of rock cooling. An investigation of the role of the titanium <span class="hlt">oxide</span> content of different rocks on stability of ferrous <span class="hlt">iron</span> <span class="hlt">oxide</span> against its transformation to ferric <span class="hlt">iron</span> <span class="hlt">oxide</span> shows that a significant correlation ( r = 0.79) does exist between the relative content of ferrous <span class="hlt">iron</span> <span class="hlt">oxide</span> and ratio of TiO2/Fe2O3. Temperature within the solar nebula at location of the Earth was within the temperature range of the TFFI. During the Earth accretion and its early evolution, ferric <span class="hlt">iron</span> <span class="hlt">oxide</span> was unstable and most likely did not exist. The first magnetic minerals containing ferric <span class="hlt">iron</span> could have appeared only after the Earth’s surface had cooled below ˜843 K. The formation of the first Algoma-type banded <span class="hlt">iron</span> formations could be used as a marker of the Earth’s surface cooling below ˜843 K.</p> <div class="credits"> <p class="dwt_author">Pilchin, Arkady N.; Eppelbaum, Lev V.</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-06-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">427</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ibj.pasteur.ac.ir/April2007/Ani.pdf"> <span id="translatedtitle">Comparative Effects of Copper, <span class="hlt">Iron</span>, Vanadium and Titanium on Low Density Lipoprotein <span class="hlt">Oxidation</span> in vitro</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Introduction: <span class="hlt">Oxidation</span> of low density lipoprotein (LDL) has been strongly implicated in the phathogenesis of atherosclerosis. The use of <span class="hlt">oxidants</span> in dietary food stuff may lead to the production of <span class="hlt">oxidized</span> LDL and may increase both the development and the progression of atherosclerosis. The present work investigated the effects of some elements including: copper (Cu), <span class="hlt">iron</span> (Fe), vanadium (V) and</p> <div class="credits"> <p class="dwt_author">Mohsen Ani; Ali Asghar Moshtaghie; Hassan Ahmadvand</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">428</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012GeCoA..96..294Y"> <span id="translatedtitle"><span class="hlt">Oxidation</span> and competitive retention of arsenic between <span class="hlt">iron</span>- and manganese <span class="hlt">oxides</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Manganese (Mn) and <span class="hlt">iron</span> (Fe) <span class="hlt">oxides</span> are ubiquitous solids in terrestrial systems that have high sorptive capacities for many trace metals, including arsenic (As). Although numerous studies have characterized the effects of As adsorption onto Fe and Mn <span class="hlt">oxides</span> individually, the fate of arsenic within mixed systems representative of natural environments has not been completely resolved. Here, we examine <span class="hlt">oxidation</span> and competitive retention of As on goethite and birnessite using a Donnan reactor, where each <span class="hlt">oxide</span> is isolated by a semi-permeable membrane through which arsenic can migrate. To initiate the Donnan reactor experiments, As(III) was simultaneously added to both chambers. Arsenic(III) injected into the birnessite chamber is rapidly <span class="hlt">oxidized</span> to As(V) and then slowly redistributes across both chambers, while that added to the goethite chamber undergoes rapid adsorption; the adsorbed As(III) on goethite subsequently undergoes desorption and diffusion into the birnessite chamber followed by <span class="hlt">oxidation</span> to As(V). With increased reaction time, As(V) is generated and preferentially partitioned onto goethite due to higher adsorption affinity compared to birnessite. Furthermore, the dissolved concentration of As(V) is controlled by the adsorption capacity of the goethite surface, which when saturated, leads to increased aqueous As concentrations; despite an increase in As(V) loading on birnessite with increasing initial As(III) concentration, the resulting aqueous As(V) concentration increase appreciably once the goethite surface is saturated. Our findings show that Mn <span class="hlt">oxides</span> in soils act as a temporary sorbent of As, but operate primarily as strong <span class="hlt">oxidants</span> responsible for transformation of As(III) to As(V), which can then strongly adsorb on the surrounding Fe <span class="hlt">oxide</span> matrix.</p> <div class="credits"> <p class="dwt_author">Ying, Samantha C.; Kocar, Benjamin D.; Fendorf, Scott</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-11-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">429</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=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> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">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 ?g/l, respectively, from an initial concentration of 20 mg/l (<span class="hlt">iron</span>) and 200 ?g/l (arsenic).</p> <div class="credits"> <p class="dwt_author">Devi, Rashmi R.; Umlong, Iohborlang M.; Das, Bodhaditya; Borah, Kusum; Thakur, Ashim J.; Raul, Prasanta K.; Banerjee, Saumen; Singh, Lokendra</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-06-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">430</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/34667564"> <span id="translatedtitle">Role of <span class="hlt">iron</span> in <span class="hlt">oxidative</span> stress in skeletal muscle atrophied by immobilization</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">To clarify the role of <span class="hlt">iron</span> in <span class="hlt">oxidative</span> stress in skeletal muscle atrophied by immobilization, we investigated the effect of deferoxamine — an <span class="hlt">iron</span>-chelating agent. Deferoxamine, <span class="hlt">iron</span>-saturated deferoxamine and double-distilled water (control) were admi