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Iron Oxide (iron + oxide)
Kinds of Iron Oxide Terms modified by Iron Oxide Selected AbstractsGiant Coercive Field of Nanometer- Sized Iron Oxide,ADVANCED MATERIALS, Issue 1 2004J. Jin Nanocrystals of iron oxide in a silica matrix exhibiting a giant Hc value of 2.0,T at room temperature are reported. The nanocomposite was obtained by combining reverse-micelle and sol,gel methods. The nanocrystals of iron oxide are composed of the ,-Fe2O3 phase, with rod-like particles 100,140,nm long and 20,40,nm wide. The Figure shows the hysteresis curve of the nanocrystals. [source] Simultaneous Catalytic Removal of Nitrogen Oxides and Soot from Diesel Exhaust Gas over Potassium Modified Iron OxideCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 9 2003S. Kureti Abstract Iron oxide modified by potassium, i.e. Fe1.9K0.1O3, exhibits high catalytic performance for the simultaneous conversion of soot and NOx into CO2 and N2. The present study shows that long-time treatment of the catalyst leads to a drastic decrease in the activity, whereas even the aged catalyst maintains considerable activity. On the other hand, long-time treatment causes selective N2 formation, i.e. no more formation of the byproduct N2O. This alteration of catalytic performance is likely due to agglomeration of the promoter potassium being present at the surface of catalyst. Detailed experiments were carried out with a more realistic diesel model exhaust gas to confirm that Fe1.9K0.1O3 is a suitable catalyst for the simultaneous removal of soot and NOx between 350 and 480 °C. It was assumed that (CO) intermediates, formed by the catalytic reaction of NOx and oxygen with the soot surface, are the reactive species in NOx -soot conversion. [source] Synthesis of Perovskite-Type Lanthanum Iron Oxide by Glycothermal Reaction of a Lanthanum,Iron Precursor.CHEMINFORM, Issue 51 2002Hiroshi Kominami Abstract For Abstract see ChemInform Abstract in Full Text. [source] Cesium Release From Tungstate and Titanate Waste Form Materials in Simulated Canister Corrosion Product-Containing SolutionsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 8 2007Vittorio Luca The leaching of two potential 137Cs waste form ceramics (Cs-containing hexagonal tungsten bronze (HTB) and hollandite) has been investigated in Fe(NO3)3 solutions of increasing concentration at 150°C over a period of 4 days. These ceramics contain within their structures reduced Mo5+/W5+ and Ti3+ species for the HTB and hollandite, respectively, which therefore might render them susceptible to oxidation-induced leaching. Elucidation of the extent and the mechanism of leaching of the Cs from these ceramics in the REDOX active iron nitrate medium has been investigated. Cesium (Cs) leached severely from both the Cs-loaded HTB and hollandite materials in iron nitrate solutions with virtually all of the immobilized Cs being extracted from both waste form materials in a period of 4 days at 150°C. In the case of hollandite, conversion to ilmenite and hematite was observed at low concentrations and was virtually complete in 0.5 mol/L Fe(NO3)3 over 4 days. In the case of the HTB, all of the Cs was extracted presumably by an ion-exchange mechanism because the structure of this oxide remained intact and iron was found in the composition. Iron oxide with a hematite structure was also easily observed in the reacted sample at high solution iron concentrations. It is shown that the leach resistance of the Cs-containing HTB can be improved by substitution of up to 20% Ti for W. [source] Iron oxide-based magnetic nanostructures bearing cytotoxic organosilicon molecules for drug delivery and therapyAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 3 2010Alla Zablotskaya Abstract The results of our own investigation on synthesis, physico-chemical and biological study of iron oxide based magnetic nanoparticles bearing cytotoxic organosilicon molecules of choline and colamine analogues, as potential agents for antitumor therapy, are summarized. These molecules contain hydrophilic head and long lipophilic tails, which are able to deepen inside the first surfactant shell (oleic acid), forming bilayer membrane like structures. Such compositions have a great privilege possessing magnetic properties, which in some cases could be essential moment in targeted drug delivery. The methodological approach has been developed and applied to the preparation of water soluble single or mixed coated biologically active nanoparticles of different types. Copyright © 2010 John Wiley & Sons, Ltd. [source] Simultaneous Catalytic Removal of Nitrogen Oxides and Soot from Diesel Exhaust Gas over Potassium Modified Iron OxideCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 9 2003S. Kureti Abstract Iron oxide modified by potassium, i.e. Fe1.9K0.1O3, exhibits high catalytic performance for the simultaneous conversion of soot and NOx into CO2 and N2. The present study shows that long-time treatment of the catalyst leads to a drastic decrease in the activity, whereas even the aged catalyst maintains considerable activity. On the other hand, long-time treatment causes selective N2 formation, i.e. no more formation of the byproduct N2O. This alteration of catalytic performance is likely due to agglomeration of the promoter potassium being present at the surface of catalyst. Detailed experiments were carried out with a more realistic diesel model exhaust gas to confirm that Fe1.9K0.1O3 is a suitable catalyst for the simultaneous removal of soot and NOx between 350 and 480 °C. It was assumed that (CO) intermediates, formed by the catalytic reaction of NOx and oxygen with the soot surface, are the reactive species in NOx -soot conversion. [source] Quantifying the effects of aggregation, particle size and components on the colour of Mediterranean soilsEUROPEAN JOURNAL OF SOIL SCIENCE, Issue 3 2004M. SÁnchez-Marańón Summary Aggregation, particle size, and chemical composition affect the colour of the soil. We have attempted to quantify and understand these effects in 12 Mediterranean soils. We measured the CIELAB colour variables hab, L*, and C*ab in aggregated and dispersed soil samples, and also in coarse sand, fine sand, silt, and clay samples before and after sequential removal of organic matter, carbonates, and Fe oxides. Grassmann's colour-mixing equations adjusted by regression analysis described the colour of the dispersed soil from its particle-size fractions with an error of 1% for hab, 4% for L*, and 9% for C*ab. This suggests that the contribution of each fraction to the colour of the dispersed soil can be accurately calculated by its colorimetric data weighted by its content and a regression coefficient, which was greatest for clay. We inferred the influence of a component within each fraction by measuring the colour changes after its removal. Iron oxides reduced hab of the silicated substrate by 19%, reduced L* by 12%, and increased C*ab by 64% in all particle-size fractions. Carbonates and organic matter had little influence: the former because they impart little colour to the silicates and the latter because there was little of it. The CIELAB colour-difference between dispersed and aggregated soil (mean ,E*ab = 15.3) was due mainly to ,L* (,14.7). Aggregation contributed to diminishing L* of dispersed soil by 34%. Scanning electron microscopy showed that Fe oxides and organic coatings cover the surface of aggregates thereby influencing soil colour. [source] Magnetically Separable Gold Catalyst for the Aerobic Oxidation of AminesCHEMCATCHEM, Issue 1 2009Linda Aschwanden Abstract A magnetically separable, recyclable gold catalyst consisting of gold nanoparticles supported on intimately mixed superparamagnetic ceria/iron oxide has been prepared by simple addition of the preformed mixed oxide support and the gold precursor, Au(OAc)3, to the reaction mixture of the aerobic oxidation of amines. The catalyst was characterized by means of X-ray diffraction (XRD), N2 adsorption, superconducting quantum-interference device (SQUID) measurements, time-of-flight secondary ion mass spectrometry (TOF-SIMS), scanning transmission electron microscopy (STEM), and scanning electron microscopy with an energy-dispersive X-ray spectrometer (SEM-EDAX). Catalytic tests with various amines showed high selectivity to the corresponding imines (87,100,%), and good separation efficiency and recyclability of the catalyst. [source] Proposing magnetic nanoparticle hyperthermia in low-field MRICONCEPTS IN MAGNETIC RESONANCE, Issue 1 2010Pádraig Cantillon-Murphy Abstract This work examines feasibility, practical advantages, and disadvantages of a combined MRI/magnetic particle hyperthermia (MPH) system for cancerous tumor treatment in low perfusion tissue. Although combined MRI/hyperthermia systems have been proposed and constructed, the current proposal differs because the hyperthermia system would be specifically designed to interact with the magnetic nanoparticles injected at the tumor site. The proposal exploits the physical similarities between the magnetic nanoparticles currently employed for MPH and those used as superparamagnetic iron oxide (SPIO) contrast agents in MR imaging. The proposal involves the addition of a rotating magnetic field RF hyperthermia source perpendicular to the MRI B0 field which operates in a similar manner to the MRI RF excitation field, B1, but at significantly higher frequency and field strength such that the magnetic nanoparticles are forced to rotate in its presence. This rotation is the source of increases in temperature which are of therapeutic benefit in cancer therapy. For rotating magnetic fields with amplitudes much smaller than B0, the nanoparticles' suspension magnetization rapidly saturates with increasing B0. Therefore, the proposal is best suited to low-field MRI systems when magnetic saturation is incomplete. In addition, careful design of the RF hyperthermia source is required to ensure no physical or RF interference with the B1 field used for MRI excitation. Notwithstanding these caveats, the authors have shown that localized steady-state temperature rises in small spherical tumors of up to 10°C are conceivable with careful selection of the nanoparticle radius and concentration, RF hyperthermia field amplitude and frequency. © 2010 Wiley Periodicals, Inc. Concepts Magn Reson Part A 36A: 36,47, 2010. [source] MR imaging for the longevity of mesenchymal stem cells labeled with poly- L -lysine,Resovist complexesCONTRAST MEDIA & MOLECULAR IMAGING, Issue 2 2010Gang Liu Abstract Superparamagnetic iron oxide (SPIO) nanoparticles are emerging as ideal probes for noninvasive cell tracking. In this study, poly- L -lysine (PLL) was mixed with Resovist to form the PLL,Resovist complexes and the control of the complexes formed by PLL and Resovist and their subsequent properties was easily achievable. MSCs could be safely and efficiently labeled for MR imaging using PLL,Resovist complexes (w/w 0.01:1) and the labeled MSCs could be detected to have definite decreased signal intensity on T2 -weight imaging until 20 days with standard 1.5,T MR equipment. This study describes a simple protocol to label MSCs using PLL,Resovist complexes and the results presented in our study can provide a basis for the application of PLL,Resovist complexes cell labeling. Copyright © 2010 John Wiley & Sons, Ltd. [source] CMR2009: 10.01: Imaging tumor necrosis with the second-generation, folate-specific ultrasmall paramagnetic iron oxide (USPIO) P1133 with magnetic resonance (MR) imaging in a transgenic mouse model for breast cancerCONTRAST MEDIA & MOLECULAR IMAGING, Issue 6 2009D. Golovko No abstract is available for this article. [source] Assessing cytotoxicity of (iron oxide-based) nanoparticles: an overview of different methods exemplified with cationic magnetoliposomesCONTRAST MEDIA & MOLECULAR IMAGING, Issue 5 2009Stefaan J. H. Soenen Abstract Iron oxide nanoparticles are the most widely used T2/T2* contrast agents and for biomedical research purposes, one of the main applications is the in vitro labeling of stem or therapeutic cells, allowing them to be subsequently tracked in vivo upon transplantation. To allow this, the nanoparticles used should not show any sign of cytotoxicity and not affect cellular physiology as this could impede normal cell functionality in vivo or lead to undesired side-effects. Assessing the biocompatibility of the nanoparticles has proven to be quite a difficult task. In the present work, a small overview of commonly used assays is presented in order to assess several aspects, such as cell viability, induction of reactive oxygen species, nanoparticle uptake, cellular morphology, cellular proliferation, actin cytoskeleton architecture and differentiation of stem cells. The main focus is on comparing the advantages and disadvantages of the different assays, highlighting several common problems and presenting possible solutions to these problems as well as pointing out the high importance of the relationship between intracellular nanoparticle concentration and cytotoxicity. Copyright © 2009 John Wiley & Sons, Ltd. [source] A new method for the aqueous functionalization of superparamagnetic Fe2O3 nanoparticlesCONTRAST MEDIA & MOLECULAR IMAGING, Issue 6 2008Fernando Herranz Abstract A new methodology for the synthesis of hydrophilic iron oxide nanoparticles has been developed. This new method is based on the direct chemical modification of the nanoparticles' surfactant molecules. Using this methodology both USPIO (ultrasmall super paramagnetic iron oxide) (hydrodynamic size smaller than 50,nm) and SPIO (super paramagnetic iron oxide) (hydrodynamic size bigger than 50,nm) were obtained. In addition, we also show that it is possible to further functionalize the hydrophilic nanoparticles via covalent chemistry in water. The magnetic properties of these nanoparticles were also studied, showing their potential as MRI contrast agents. Copyright © 2008 John Wiley & Sons, Ltd. [source] A new type of susceptibility-artefact-based magnetic resonance angiography: intra-arterial injection of superparamagnetic iron oxide particles (SPIO) A Resovist® in combination with TrueFisp imaging: a feasibility studyCONTRAST MEDIA & MOLECULAR IMAGING, Issue 5 2006Robbert M. Maes Abstract The goal of this study was to evaluate the use of super paramagnetic particles of iron oxide (SPIO) as a dark blood contrast agent, in combination with a bright blood steady-state free precession sequence for magnetic resonance angiography (MRA), in an animal model. The original concentration of the SPIO of 500,mmol Fe/l and dilutions to 250, 125, 60, 30, 10 and 5,mmol Fe/l were intra-arterially injected into the aorta of a pig. Then the dilution of 10,mmol Fe/l was chosen for repeated intra-arterial injections into two pigs. During these intra-arterial SPIO injections MR images were acquired with a 1.5,T scanner. Signal intensity measurements were performed in the aorta. The signal-to-noise ratio during SPIO bolus passage was significantly less than during baseline conditions (Fisher's F -ratio 159.8, p,<,0.005) or the recovery signal-to-noise ratio (Fisher's F -ratio 144.6, p,<,0.005). Also, confirmation of flow distal to the catheter-tip position was possible. The use of SPIO as a dark blood agent in combination with a bright blood MR imaging sequence is feasible. Temporary loss of intraluminal signal occurs due to local decrease of the signal because of induction of local inhomogeneities after mixture the present blood and SPIO solution. It provides immediate information about blood flow distal to the catheter and is a potentially useful to guide intravascular MR-interventional procedures. Copyright © 2006 John Wiley & Sons Ltd. [source] Designed Multifunctional Nanocomposites for Biomedical ApplicationsADVANCED FUNCTIONAL MATERIALS, Issue 10 2010Humphrey H. P. Yiu Abstract The assembly of multifunctional nanocomposite materials is demonstrated by exploiting the molecular sieving property of SBA-16 nanoporous silica and using it as a template material. The cages of the pore networks are used to host iron oxide magnetic nanoparticles, leaving a pore volume of 0.29,cm3,g,1 accessible for drug storage. This iron oxide,silica nanocomposite is then functionalized with amine groups. Finally the outside of the particle is decorated with antibodies. Since the size of many protein molecules, including that of antibodies, is too large to enter the pore system of SBA-16, the amine groups inside the pores are preserved for drug binding. This is proven using a fluorescent protein, fluorescein-isothiocyanate-labeled bovine serum albumin (FITC-BSA), with the unreacted amine groups inside the pores dyed with rhodamine B isothiocyanate (RITC). The resulting nanocomposite material offers a dual-targeting drug delivery mechanism, i.e., magnetic and antibody-targeting, while the functionalization approach is extendable to other applications, e.g., fluorescence,magnetic dual-imaging diagnosis. [source] Layer-By-Layer Dendritic Growth of Hyperbranched Thin Films for Surface Sol,Gel Syntheses of Conformal, Functional, Nanocrystalline Oxide Coatings on Complex 3D (Bio)silica TemplatesADVANCED FUNCTIONAL MATERIALS, Issue 17 2009Guojie Wang Abstract Here, a straightforward and general method for the rapid dendritic amplification of accessible surface functional groups on hydroxylated surfaces is described, with focus on its application to 3D biomineral surfaces. Reaction of hydroxyl-bearing silica surfaces with an aminosilane, followed by alternating exposure to a dipentaerythritol-derived polyacrylate solution and a polyamine solution, allows the rapid, layer-by-layer (LBL) build-up of hyperbranched polyamine/polyacrylate thin films. Characterization of such LBL-grown thin films by AFM, ellipsometry, XPS, and contact angle analyses reveals a stepwise and spatially homogeneous increase in film thickness with the number of applied layers. UV,Vis absorption analyses after fluorescein isothiocyanate labeling indicate that significant amine amplification is achieved after the deposition of only 2 layers with saturation achieved after 3,5 layers. Use of this thin-film surface amplification technique for hydroxyl-enrichment of biosilica templates facilitates the conformal surface sol,gel deposition of iron oxide that, upon controlled thermal treatment, is converted into a nanocrystalline (,9.5,nm) magnetite (Fe3O4) coating. The specific adsorption of arsenic onto such magnetite-coated frustules from flowing, arsenic-bearing aqueous solutions is significantly higher than for commercial magnetite nanoparticles (,50,nm in diameter). [source] An actualistic perspective into Archean worlds , (cyano-)bacterially induced sedimentary structures in the siliciclastic Nhlazatse Section, 2.9 Ga Pongola Supergroup, South AfricaGEOBIOLOGY, Issue 1 2008N. NOFFKE ABSTRACT Extensive microbial mats colonize sandy tidal flats that form along the coasts of today's Earth. The microbenthos (mainly cyanobacteria) respond to the prevailing physical sediment dynamics by biostabilization, baffling and trapping, as well as binding. This biotic,physical interaction gives rise to characteristic microbially induced sedimentary structures (MISS) that differ greatly from both purely physical structures and from stromatolites. Actualistic studies of the MISS on modern tidal flats have been shown to be the key for understanding equivalent fossil structures that occur in tidal and shelf sandstones of all Earth ages. However, until now the fossil record of Archean MISS has been poor, and relatively few specimens have been found. This paper describes a study location that displays a unique assemblage with a multitude of exceptionally preserved MISS in the 2.9-Ga-old Pongola Supergroup, South Africa. The ,Nhlazatse Section' includes structures such as ,erosional remnants and pockets', ,multidirected ripple marks', ,polygonal oscillation cracks', and ,gas domes'. Optical and geochemical analyses support the biogenicity of microscopic textures such as filamentous laminae or ,orientated grains'. Textures resembling filaments are lined by iron oxide and hydroxides, as well as clay minerals. They contain organic matter, whose isotope composition is consistent with carbon of biological origin. The ancient tidal flats of the Nhlazatse Section record four microbial mat facies that occur in modern tidal settings as well. We distinguish endobenthic and epibenthic microbial mats, including planar, tufted, and spongy subtypes. Each microbial mat facies is characterized by a distinct set of MISS, and relates to a typical tidal zone. The microbial mat structures are preserved in situ, and are consistent with similar features constructed today by benthic cyanobacteria. However, other mat-constructing microorganisms also could have formed the structures in the Archean tidal flats. [source] Superparamagnetic iron oxide,enhanced magnetic resonance images of hepatocellular carcinoma: Correlation with histological gradingHEPATOLOGY, Issue 2 2000Ph.D., Yasuharu Imai M.D. Superparamagnetic iron oxide (SPIO),enhanced magnetic resonance (MR) imaging has been used for the detection of hepatic tumors. However, little is known about this technique in relation to hepatocellular carcinoma (HCC). The aim of this study was to investigate whether SPIO,enhanced MR imaging can be useful in assessing histological grades of HCC. The authors studied histologically proven tumors including 31 HCCs and 6 dysplastic nodules. The ratio of the Kupffer-cell count in the tumorous tissue relative to that in the nontumorous tissue (Kupffer-cell,count ratio) decreased as HCCs became less well differentiated. The ratio of the intensity of the tumorous lesion to that of the nontumorous area on SPIO,enhanced MR images (SPIO intensity ratio) correlated inversely with Kupffer-cell,count ratio in HCCs and dysplastic nodules (r = ,.826, P< .001) and increased as the degree of differentiation of HCCs decreased, indicating that the uptake of SPIO in HCCs decreased as the degree of differentiation of HCCs declined. All of the dysplastic nodules and some well-differentiated HCCs showed hypointense or isointense enhancement, relative to the surrounding liver parenchyma, indicating greater or similar uptake of SPIO in the tumor when compared with nontumorous areas. These results suggest that SPIO,enhanced MR imaging reflects Kupffer-cell numbers in HCCs and dysplastic nodules, and is useful for estimation of histological grading in HCCs, although uncertainties persist in differentiating dysplastic nodules from well-differentiated HCCs. [source] Infiltration pattern in a regolith,fractured bedrock profile: field observation of a dye stain patternHYDROLOGICAL PROCESSES, Issue 2 2006Jae Gon Kim Abstract We examined the infiltration pattern of water in a regolith,bedrock profile consisting of two overburdens (OB1 and OB2), a buried rice paddy soil (PS), two texturally distinctive weathered materials (WM1 and WM2) and a fractured sedimentary rock (BR), using a Brilliant Blue FCF dye tracer. A black-coloured coating in conducting fractures in WM1, WM2 and BR was analysed by X-ray diffraction and scanning electron microscopy. The dye tracer penetrated to greater than 2 m depth in the profile. The macropore flow and saturated interflow were the major infiltration patterns in the profile. Macropore flow and saturated interflow were observed along fractures in WM1, WM2 and BR and at the dipping interfaces of PS,WM1, PS,WM2 and PS,BR respectively. Heterogeneous matrix flow occurred in upper overburden (OB1) and PS. Compared with OB1, the coarser textured OB2 acted as a physical barrier for vertical flow of water. The PS with low bulk density and many fine roots was another major conducting route of water in the profile. Manganese oxide and iron oxide were positively identified in the black coating material and had low crystallinity and high surface area, indicating their high reactivity with conducting contaminants. Copyright © 2006 John Wiley & Sons, Ltd. [source] Inorganic Nanoparticles for MRI Contrast AgentsADVANCED MATERIALS, Issue 21 2009Hyon Bin Na Abstract Various inorganic nanoparticles have been used as magnetic resonance imaging (MRI) contrast agents due to their unique properties, such as large surface area and efficient contrasting effect. Since the first use of superparamagnetic iron oxide (SPIO) as a liver contrast agent, nanoparticulate MRI contrast agents have attracted a lot of attention. Magnetic iron oxide nanoparticles have been extensively used as MRI contrast agents due to their ability to shorten T2* relaxation times in the liver, spleen, and bone marrow. More recently, uniform ferrite nanoparticles with high crystallinity have been successfully employed as new T2 MRI contrast agents with improved relaxation properties. Iron oxide nanoparticles functionalized with targeting agents have been used for targeted imaging via the site-specific accumulation of nanoparticles at the targets of interest. Recently, extensive research has been conducted to develop nanoparticle-based T1 contrast agents to overcome the drawbacks of iron oxide nanoparticle-based negative T2 contrast agents. In this report, we summarize the recent progress in inorganic nanoparticle-based MRI contrast agents. [source] Synthesis and Characterization of Iron Oxide Derivatized Mutant Cowpea Mosaic Virus Hybrid Nanoparticles,ADVANCED MATERIALS, Issue 24 2008Alfredo A. Martinez-Morales A novel nanoparticle hybrid is attained by the covalent attachment of iron oxide (, -Fe2O3) nanoclusters onto the surface of a mutagenized cow pea mosaic virus (CPMV-T184C). Using a stepwise substrate-based integration, monodisperse CPMV-IO hybrids are anchored on a gold substrate. The physical and magnetic properties of individual CPMV-IO hybrids are qualitatively investigated by atomic/magnetic force microscopy (AFM/ MFM). During MFM characterization a ,boundary-effect' is observed at the CPMV/IO interface. [source] Fabrication and Application of an Oxide Thermoelectric SystemINTERNATIONAL JOURNAL OF APPLIED CERAMIC TECHNOLOGY, Issue 4 2007Ryoji Funahashi A plate-shaped thermoelectric module was prepared using 140 pairs of p -type Ca3Co4O9 (Co-349) and n -type LaNiO3 (Ni-113) bulks. The hot-pressed thermoelectric oxide bulks were connected with an Ag paste, incorporating oxide powder, and Ag sheets. The module's open-circuit voltage increases with increasing hot-side temperature (TH) and reaches 4.5 V at a TH of 1072 K in air. No deterioration in output power was seen when power generation was carried out 10 times at a TH of 723 K with intermediate cooling to room temperature. The module was successfully used to charge a lithium-ion battery in a mobile phone. Thermoelectric modules composed of p -type Co-349 and n -type CaMnO3 (Mn-113) bulks, which have a pipe shape, were constructed using Ag electrodes and stainless-steel tubes. The devices were connected with the stainless-steel tube coated with ZrO2 by thermal spray using a dielectric paste composed of silica glass and iron oxide. Power generation was carried out in flame by combustion of natural gas. Water flowed inside the stainless-steel tube for cooling. One module consisting of 54 pairs of legs can generate 1.5 V, 0.28 W, and steam simultaneously by installing in an instantaneous water heater. Power generation was carried out four times with intermediate cooling. Deterioration in the open-circuit voltage of the module was not observed after the fourth combustion. [source] Magnetite-Loaded Polymeric Micelles as Ultrasensitive Magnetic-Resonance Probes,ADVANCED MATERIALS, Issue 16 2005H. Ai Increased contrast in magnetic resonance imaging (MRI) is accomplished using polymeric micelles loaded with superparamagnetic iron oxide (SPIO) nanoparticles encapsulated in biocompatible, biodegradable poly(,-caprolactone)- b -poly(ethylene glycol) (PCL- b -PEG) copolymers (see Figure). The loaded micelles show significantly improved T2 relaxivities and remarkable MRI detection sensitivity. [source] Giant Coercive Field of Nanometer- Sized Iron Oxide,ADVANCED MATERIALS, Issue 1 2004J. Jin Nanocrystals of iron oxide in a silica matrix exhibiting a giant Hc value of 2.0,T at room temperature are reported. The nanocomposite was obtained by combining reverse-micelle and sol,gel methods. The nanocrystals of iron oxide are composed of the ,-Fe2O3 phase, with rod-like particles 100,140,nm long and 20,40,nm wide. The Figure shows the hysteresis curve of the nanocrystals. [source] Structure of magnetic poly(oxyethylene),siloxane nanohybrids doped with FeII and FeIIIJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 4 2003N. J. O. Silva Hybrid organic,inorganic nanocomposites doped with FeII and FeIII ions and exhibiting interesting magnetic properties have been obtained by the sol,gel process. The hybrid matrix of these ormosils (organically modified silicates), classed as di-ureasils and termed U(2000), is composed of poly(oxyethylene) chains of variable length grafted to siloxane groups by means of urea crosslinkages. Iron perchlorate and iron nitrate were incorporated in the di-ureasil matrices, leading to compositions within the range 80 ,n, 10, n being the molar ratio of ether-type O atoms per cation. The structure of the doped di-ureasils was investigated by small-angle X-ray scattering (SAXS). For FeII -doped samples, SAXS results suggest the existence of a two-level hierarchical structure. The primary level is composed of spatially correlated siloxane clusters embedded in the polymeric matrix and the secondary, coarser level consists of domains where the siloxane clusters are segregated. The structure of FeIII -doped hybrids is different, revealing the existence of iron oxide based nanoclusters, identified as ferrihydrite by wide-angle X-ray diffraction, dispersed in the hybrid matrix. The magnetic susceptibility of these materials was determined by zero-field-cooling and field-cooling procedures as functions of both temperature and field. The different magnetic features between FeII - and FeIII -doped samples are consistent with the structural differences revealed by SAXS. While FeII -doped composites exhibit a paramagnetic Curie-type behaviour, hybrids containing FeIII ions show thermal and field irreversibilities. [source] Ferucarbotran expands area treated by radiofrequency ablation in rabbit liversJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 7pt2 2008Tatsuya Miyake Abstract Background and Aim:, Several studies have examined the factors involved with expansion of the coagulation volume following radiofrequency ablation (RFA). Ferucarbotran contains superparamagnetic iron oxide that generates heat in a radiofrequency electric field and may have an effect on the area affected by RFA. We attempted to determine whether ferucarbotran administration expands radiofrequency-ablated volume using a rabbit model. Methods:, A total of 15 male Japanese white rabbits (16 weeks old) were used and divided into three groups of five each. A 1-mL saline solution was given intravenously into a dorsal ear vein in the control group, whereas 1 mL ferucarbotran solution (0.016 mL/kg bodyweight) was given to the common-dose group and 1 mL of a twofold concentrated ferucarbotran solution (0.032 mL/kg bodyweight) was given to the high-dose group. RFA was performed with a cool-tip electrode 4 h after the administration and immediately thereafter the rabbits were killed, and the volume of the ablated area measured using magnetic resonance imaging (MRI). Following the MRI analysis, the rabbit's livers were resected, and the maximum short axis diameter of the ablated area in each was measured. Results:, None of the rabbits died during the RFA procedure. The volume of the ablated area estimated on MR images in the ferucarbotran-administered groups was larger than that in the control group. Further, our macroscopic assessment showed that the maximum short axis diameter had a tendency to increase with ferucarbotran administration. Conclusion:, Ferucarbotran may expand the area treated by RFA. [source] Syngas chemical looping gasification process: Bench-scale studies and reactor simulationsAICHE JOURNAL, Issue 8 2010Fanxing Li Abstract The syngas chemical looping process co-produces hydrogen and electricity from syngas through the cyclic reduction and regeneration of an iron oxide based oxygen carrier. In this article, the reducer, which reduces the oxygen carrier with syngas, is investigated through thermodynamic analysis, experiments, and ASPEN Plus® simulation. The thermodynamic analysis indicates that the countercurrent moving-bed reducer offers better gas and solids conversions when compared to the fluidized-bed reducer. The reducer is continuously operated for 15 h in a bench scale moving-bed reactor. A syngas conversion in excess of 99.5% and an oxygen carrier conversion of nearly 50% are obtained. An ASPEN Plus® model is developed which simulates the reducer performance. The results of simulation are consistent with those obtained from both the thermodynamic analysis and experiments. Both the experiments and simulation indicate that the proposed SCL reducer concept is feasible. © 2009 American Institute of Chemical Engineers AIChE J, 2010 [source] The kinetics of the reduction of iron oxide by carbon monoxide mixed with carbon dioxideAICHE JOURNAL, Issue 4 2010C. D. Bohn Abstract Results are reported for the repeated reduction of iron oxide particles, 300,425 ,m diameter, by a mixture of CO, CO2, and N2 in a fluidized bed of 20 mm internal diameter. The conclusions were as follows: (1) Reduction of either Fe2O3 to Fe3O4 or of Fe3O4 to Fe0.947O is first-order in CO. (2) With the particle sizes used, the rates of the reduction reactions are controlled by intrinsic chemical kinetics. Activation energies and pre-exponential factors are reported. (3) The first cycle gave anomalous results, but (a) the rate of reduction of Fe2O3 to Fe3O4 remained constant over cycles 2,10; (b) the rate of reduction of Fe3O4 to Fe0.947O declined by 60,85% over cycles 2,10. (4) The rates of reduction declined with solids conversion down to zero at 80% conversion. The rates were incorporated into a conventional model of a fixed bed, which was used to predict, satisfactorily, the reduction behavior of iron oxide. © 2009 American Institute of Chemical Engineers AIChE J, 2010 [source] Quantification of superparamagnetic iron oxide-mediated signal intensity change in patients with liver cirrhosis using T2 and T2* mapping: A preliminary reportJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 6 2010Yong Eun Chung MD Abstract Purpose: To quantify the accumulation of superparamagnetic iron oxide (SPIO) in patients with and without liver cirrhosis using T2 and T2* mapping. Materials and Methods: We enrolled 10 patients without liver cirrhosis and 30 patients with liver cirrhosis (Child-Pugh class A, n = 18; and B/C, n = 12). T2 and T2* mapping were performed before and after SPIO administration. The reductions in T2 (,T2) and T2* (,T2*) after SPIO administration were compared between the control and liver cirrhosis groups and the control, Child-Pugh A, and Child Pugh B/C groups. Results: There were significant differences in ,T2 (22.2 ± 4.4 and 15.1 ± 7.0) and ,T2* values (24.3 ± 3.3 and 16.8 ± 8.1) (P = 0.005 and P < 0.001) between the control and the liver cirrhosis groups. There was a significant difference in the ,T2* between the Child-Pugh A and Child-Pugh B/C groups (P < 0.001) and in the ,T2 and ,T2* between the control and Child-Pugh B/C groups (P = 0.018 and P < 0.001). Conclusion: ,T2 and ,T2* are significantly larger in patients without liver cirrhosis than those with liver cirrhosis. ,T2* is also significantly larger in Child-Pugh class A patients than those in Child-Pugh B/C. J. Magn. Reson. Imaging 2010;31:1379,1386. © 2010 Wiley-Liss, Inc. [source] Comparison of ferucarbotran-enhanced fluid-attenuated inversion-recovery echo-planar, T2-weighted turbo spin-echo, T2*-weighted gradient-echo, and diffusion-weighted echo-planar imaging for detection of malignant liver lesionsJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 3 2010Yoshihiko Fukukura MD Abstract Purpose: To compare the diagnostic accuracy of superparamagnetic iron oxide (SPIO)-enhanced fluid-attenuated inversion-recovery echo-planar imaging (FLAIR EPI) for malignant liver tumors with that of T2-weighted turbo spin-echo (TSE), T2*-weighted gradient-echo (GRE), and diffusion-weighted echo-planar imaging (DW EPI). Materials and Methods: SPIO-enhanced magnetic resonance imaging (MRI) that included FLAIR EPI, T2-weighted TSE, T2*-weighted GRE, and DW EPI sequences was performed using a 3 T system in 54 consecutive patients who underwent surgical exploration with intraoperative ultrasonography. A total of 88 malignant liver tumors were evaluated. Images were reviewed independently by two blinded observers who used a 5-point confidence scale to identify lesions. Results were correlated with results of histopathologic findings and surgical exploration with intraoperative ultrasonography. The accuracy of each MRI sequence was measured with jackknife alternative free-response receiver operating characteristic analysis. The sensitivity of each observer with each MRI sequence was compared with McNemar's test. Results: Accuracy values were significantly higher with FLAIR EPI sequence (0.93) than with T2*-weighted GRE (0.80) or DW EPI sequences (0.80) (P < 0.05). Sensitivity was significantly higher with the FLAIR EPI sequence than with any of the other sequences. Conclusion: SPIO-enhanced FLAIR EPI sequence was more accurate in the diagnosis of malignant liver tumors than T2*-weighted GRE and DW EPI sequences. SPIO-enhanced FLAIR EPI sequence is helpful for the detection of malignant liver tumors. J. Magn. Reson. Imaging 2010;31:607,616. ©2010 Wiley-Liss, Inc. [source] | ||||||||||||||||||||||||||||