RESUMO
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.
Assuntos
Cobalto , Nanocompostos , Compostos Férricos , MagnetismoRESUMO
This study aimed to investigate the effects of hypoxia and serum deprivation on regulation of fucosyltransferase-3 (FUT3) expression in breast cancer cells. MATERIALS AND METHODS: FUT3 expression was evaluated in T47D and MCF7 cells. Transcriptional and protein analysis was performed under hypoxia and serum deprivation conditions after 6 and 24 hours; and after 24 and 48 hours, respectively. RESULTS: In T47D cells, experimental conditions induced a significant decrease in FUT3 expression at both, transcriptional and protein levels, while in MCF7 cells the same conditions induced a significant increase of FUT3 expression. CONCLUSIONS: Regulation of FUT3 expression under hypoxic and serum deprivation conditions may be involved in the acquisition of advantages related to apoptosis resistance and metastasis promotion, according to the intrinsic differences presented by T47D and MCF7 cells.