Influence of iron addition on the microstructure and the electrochemical corrosion of Al-Zn-Mg alloys

The effect of Fe addition on the microstructural properties and the corrosion resistance of Al-Zn-Mg alloys submitted to different heat treatments (cast, annealed and aged), has been studied in chloride solutions using optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray (EDX), cyclic polarization (CP) and open circuit potential (o.c.p.) measurements. The presence of 0.3% Fe in the alloy limited the growth of the MgZn2 precipitates, both in the annealed and in the quenched specimens. No effect of Cr on the grain size in the presence of Fe was found because of the accumulation of Cr in the Fe-rich particles. Fe in the Al-Zn-Mg alloys also made them more susceptible to pitting. Pitting occurred mainly near the Fe-rich particles both, under o.c.p. conditions in O-2-saturated solutions and during the CP.

Colloidal particles: Spherical yttrium iron garnet

The purpose of this work is to obtain spherical particles YIG from micrometric to nanometric scales. The spherical particles were obtained from cation hydrolysis in acid medium by adding urea or ammonia in order to carry out a homogeneous nucleation process up to 90 degrees C. Different composition and morphology were achieved by changing reactant concentrations, precipitation agent and stabilizing agent. X-ray diffractometry, electrophoretic mobility, transmission and scanning electron microscopies were carried out on these particles to investigate the phase identification, mobility, morphology and particle size. Crystalline YIG, with spherical characteristics, was obtained. The surface potential presented different characteristics for different dispersion media.

Iron Oxide Versus Fe55Pt45/Fe3O4: Improved Magnetic Properties of Core/Shell Nanoparticles for Biomedical Applications

In this paper, synthesis of the Fe55Pt45/Fe3O4 core/shell structured nanoparticles using the modified polyol process combined with the seed-mediated growth method is reported. Iron oxide shell thickness was tuned controlling the Fe(acac)(3)/FePt seeds in the reaction medium. Annealing of the core/shell structure leads to iron-rich layer formation around the hard FePt phase in the nanoparticle core. However, the 2 nm Fe3O4 shell thickness seems to be the limit to obtain the enhanced magnetization close to the alpha-Fe and preserving an iron oxide shell after annealing at 500 degrees C for 30 min in a reducing atmosphere. The presence of both the oxide layer on nanoparticle surface and an intermediate iron-rich FePt layer after annealing promote strong decreases in the coercive field of the 2-nm-oxide shell thickness. These annealed nanoparticles were functionalized with dextran, presenting the enhanced characteristics for biomedical applications such as higher magnetization, very low coercivity, and a slightly iron oxide passivated layer, which leads an easy functionalization and decreases the nanoparticle toxicity.

Electrochromic Switching Mechanism of Iron Hexacyanoferrates Molecular Compounds: The Role of Fe2+(CN)(6) Vacancies

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Electrochemical capacitance spectroscopy and capacitive relaxation of the changeover process in iron hexacyanoferrate molecular compound

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Zero valent iron mediated degradation of the pharmaceutical diazepam

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Parameters affecting sulfonamide photo-Fenton degradation - Iron complexation and substituent group

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Paracetamol degradation intermediates and toxicity during photo-Fenton treatment using different iron species

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Decomposition kinetics of iron (III)-diclofenac compound

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Photo-Fenton degradation of the herbicide tebuthiuron under solar irradiation: Iron complexation and initial intermediates

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Diclofenac Abatement using Modified Solar Photo-Fenton Process with Ammonium Iron(III) Citrate

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Determination of Copper, Iron, Nickel and Zinc in fuel kerosene by FAAS after adsorption and pre-concentration on 2-aminothiazole-modified silica gel

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Iron chelating-mediated antioxidant activity of Plectranthus barbatus extract on mitochondria

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Lipid peroxidation, antioxidant enzymes and glutathione levels in human erythrocytes exposed to colloidal iron hydroxide in vitro

The free form of the iron ion is one of the strongest oxidizing agents in the cellular environment. The effect of iron at different concentrations (0, 1, 5, 10, 50, and 100 µM Fe3+) on the normal human red blood cell (RBC) antioxidant system was evaluated in vitro by measuring total (GSH) and oxidized (GSSG) glutathione levels, and superoxide dismutase (SOD), catalase, glutathione peroxidase (GSH-Px) and reductase (GSH-Rd) activities. Membrane lipid peroxidation was assessed by measuring thiobarbituric acid reactive substance (TBARS). The RBC were incubated with colloidal iron hydroxide and phosphate-buffered saline, pH 7.45, at 37oC, for 60 min. For each assay, the results for the control group were: a) GSH = 3.52 ± 0.27 µM/g Hb; b) GSSG = 0.17 ± 0.03 µM/g Hb; c) GSH-Px = 19.60 ± 1.96 IU/g Hb; d) GSH-Rd = 3.13 ± 0.17 IU/g Hb; e) catalase = 394.9 ± 22.8 IU/g Hb; f) SOD = 5981 ± 375 IU/g Hb. The addition of 1 to 100 µM Fe3+ had no effect on the parameters analyzed. No change in TBARS levels was detected at any of the iron concentrations studied. Oxidative stress, measured by GSH kinetics over time, occurs when the RBC are incubated with colloidal iron hydroxide at concentrations higher than 10 µM of Fe3+. Overall, these results show that the intact human RBC is prone to oxidative stress when exposed to Fe3+ and that the RBC has a potent antioxidant system that can minimize the potential damage caused by acute exposure to a colloidal iron hydroxide in vitro.