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We report an experimental study of the bimagnetic nanocomposites CoFe2/CoFe2O4. The precursor material, CoFe2O4 was prepared using the conventional stoichiometric combustion method. The nano-structured material CoFe2/CoFe2O4 was obtained by total oxygen reduction of CoFe2O4 using a thermal treatment at 350 °C in H2 atmospheres following the partial oxidation in O2 atmospheres at 380 °C during 120; 30; 15, 10, and 5 min. The X-ray diffraction, Mössbauer spectroscopy and transmission electronic microscopy images confirmed the formation of the material CoFe2/CoFe2O4. The magnetic hysteresis for the nanocomposite with different saturation magnetization (from 87 to 108 emu/g) also confirms the formation of the CoFe2/CoFe2O4 with different content of CoFe2O4. Furthermore, the magnetic hysteresis curves for all samples presented a single magnetic behavior, suggesting the magnetic coupling between the phases of the nanocomposite. The effects of high energy milling on the magnetic properties of the precursor material and nanocomposites samples were evaluated.

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Iron oxide nanoparticles (FeONPs) prepared with plant extracts have been emerging as green and sustainable materials. FeONPs are usually amorphous due to the chelation of the tea polyphenols (TPs) to the iron, and the real nature of the iron compounds is not completely understood. The main goal of this study was to investigate the behavior of the green FeONPs synthesized from an Fe3+ salt and Cammelia sinensis (black tea) extract upon thermal treatment, in order to remove TPs and enable the formation of crystalline materials suitable for a thorough characterization and with the potential for diverse applications. The as-prepared FeONPs were assigned as mixed-valence Fe(III) oxyhydroxides and Fe(II)/Fe(III) ions bound to TPs. A detailed description of the phase transformation upon heating revealed the formation of the rare nano ß-Fe2O3 phase at 400 °C, followed by a transformation to α-Fe2O3 as the temperature increased. Above 600 °C, the unprecedented formation of FePO4 and Fe3PO7 was observed, produced from the reaction of Fe2O3 and free phosphate ions present in the black tea leaves, Fe3PO7 being the major phase obtained at 900 °C. Finally, the catalytic potential of the FeONPs to treat the azo dye methyl orange through a heterogeneous Fenton-like system was investigated.

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This study aims to prepare environmentally friendly iron catalysts supported on silica, using glycerol as green reducing and stabilizing agent, for application in heterogeneous Fenton degradation of the pollutant dye methyl orange (MO). The catalysts were characterized by X-ray powder diffraction, atomic absorption spectroscopy, scanning electron microscopy, transmission electron microscopy, thermogravimetric analyses, Mössbauer and Fourier transform infrared spectroscopies, which revealed the formation of iron(II)/(III) oxalates from the oxidation of glycerol by the iron(III) nitrate precursor. Besides, iron oxihydroxide nanoparticles with superparamagnetic behavior were also formed. Iron catalysts prepared in the presence of nickel(II) or zinc(II) nitrates lead to the formation of the corresponding oxalates. The catalysts were able to degrade MO, efficiently in 180 min of reaction. Fe/SiO2 furnished higher reaction rates, followed by Zn4Fe2/SiO2, which presented higher iron content as well as the smallest nanoparticles. Reaction parameters such as catalyst dosage, hydrogen peroxide concentration, pH and reaction temperature were investigated.

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Objetivo: comparar la eficacia de la prevención no farmacológica estándar (PnFE) versus la prevención no farmacológica reforzada (PnFR), consistente en prevención no farmacológica estándar más terapia ocupacional (TO) precoz e intensiva, en la incidencia del delirium en adultos mayores (AM) ingresados a unidad de pacientes críticos (UPC). Diseño: ensayo clínico randomizado, en UPC del Hospital Clínico de la Universidad de Chile (HCUCH). Sujetos: 70 pacientes de edad igual o superior a 60 años, ingresados al HCUCH entre abril y octubre del 2011, con necesidad de ingreso a UPC para monitorización, hospitalización por enfermedad aguda/crónica descompensada, con consentimiento del paciente o familiar y sin presencia de delirium al ingreso ni deterioro cognitivo previo al estudio. Materiales y métodos: PnFE (grupo control) consiste en: reorientación, movilización precoz, corrección de déficit sensoriales, manejo ambiental, protocolo de sueño y reducción de fármacos anticolinérgicos, versus PnFR (grupo experimental), que considera las siguientes áreas de intervención de TO: estimulación polisensorial, posicionamiento, estimulación cognitiva, entrenamiento en actividades de la vida diaria básica, estimulación motora de extremidades superiores y participación familiar; durante 5 días, dos veces al día. Se evaluó la presencia del delirium, con el CAM dos veces al día durante 5 días, y la severidad de éste con DRS; previo al alta se evaluó, independencia funcional con FIM, estado cognitivo con MMSE y fuerza de garra con dinamómetro de Jamar. Resultados: la PnFR de TO se asocia a menor incidencia de delirium, afectando al 16,1 por ciento del grupo con prevención no farmacológica estándar versus un 3,1 por ciento del con prevención no farmacológica reforzada, así como a menos días de hospitalización (20,6 días versus 10,4 p=.009). La independencia funcional al alta se mantiene en aspectos cognitivos (32,5 versus 32,9) mientras que en aspectos motores aumenta...

Objective: to compare the efficacy of standard non pharmacological prevention of delirium versus intensified prevention of delirium (standard prevention plus early and intensive occupational therapy) in the incidence of delirium in older adults (OA) admitted to critical patient unit (CPU). Desing: randomized control trial, blinded to outcome evaluator, in the CPU of Hospital Clínico Universidad de Chile. Subjects: 70 patients aged 60 years or older, admitted to CPU between April and October of 2011, with need for admission to CPU for monitoring, acute or decompensated chronic illness, without cognitive impairment and consent by patient or family member. Materials and methods: standard prevention group consisted in: reorienting, early mobilization, correction of sensory deficit, environmental management, protocol of sleep and reduction of drugs, and intensified prevention based on standard measured plus early and intensive Occupational therapy: multisensory stimulation, positioning, cognitive stimulation, training in activities of daily living, motor stimulation of the upper extremities and family participation, twice a day for 5 days. Delirium was evaluated (twice a day for 5 days) with CAM and severity with DRS. Primary outcome was delirium incidence, and secondarily were functional independence (FIM), cognitive status (MMSE) and strength of grip with jamar dynamometer at leaving. Results: early intervention and intensive occupational therapy is associated with lower incidence of delirium, affecting 16.1 percent of non-pharmacological standard prevention group and 3.1 percent of intensified prevention group, as well as fewer days of hospitalization (20, 6 days versus 10,4, p= 0,009). The functional independence at leaving keeps in cognitive (32.5 versus 32.9) and is increases significantly in motor aspects (46.5 versus 58.3 l, P =. 03). Conclusion: standard prevention plus early intensive intervention of occupational therapy is effective in...

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(57)Fe Mössbauer spectroscopy has been used to investigate the structural and magnetic phase transitions of CaFe2As2 (T(N) = 173 K) single crystals. For this compound we found that V(ZZ) is positive and parallel to the c-axis of the tetragonal structure. For CaFe2As2 a magnetic hyperfine field B(hf) was observed at the (57)Fe nucleus below T(N) ~173 K. Analysis of the temperature dependence of B(hf) data using the Bean-Rodbell model shows that the Fe spins undergo a first-order magnetic transition at ~173 K. A collinear antiferromagnetic structure is established below this temperature with the Fe spin lying in the (a, b) plane. Below T(N) the paramagnetic fraction of Fe decreases down to 150 K and for lower temperatures all the Fe spins are magnetically ordered.

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(57)Fe Mössbauer spectroscopy has been used to investigate the magnetic order of non-superconducting NdFeAsO (T(N) = 140 K) and superconducting NdFeAsO(0.88)F(0.12) (T(c) = 45 K). A magnetic hyperfine field B(hf) was observed at the (57)Fe nucleus below T(N)∼140 K for NdFeAsO. Below ∼2 K an increase of B(hf) relative to the saturation value was attributed to the transferred B(hf) at the Fe site resulting from the collinear antiferromagnetic (AF) spin structure of the Nd moments. The analysis of the spectra is consistent with a commensurate AF order of Fe spins. No  B(hf) is observed in superconducting NdFeAsO(0.88)F(0.12) down to 1.5 K.