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In the present work, we developed hybrid nanostructures based on ZnO films deposited on macroporous silicon substrates using the sol-gel spin coating and ultrasonic spray pyrolysis (USP) techniques. The changes in the growth of ZnO films on macroporous silicon were studied using a UV-visible spectrometer, an X-ray diffractometer (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM). XRD analysis revealed the beneficial influence of macroporous silicon on the structural properties of ZnO films. SEM micrographs showed the growth and coverage of ZnO granular and flake-like crystals inside the pores of the substrate. The root mean square roughness (RMS) measured by AFM in the ZnO grown on the macroporous silicon substrate was up to one order of magnitude higher than reference samples. These results prove that the methods used in this work are effective to cover porous and obtain nano-morphologies of ZnO. These morphologies could be useful for making highly sensitive gas sensors.
RESUMO
Preliminary results on the fabrication of a memristive device made of zinc oxide (ZnO) over a mesoporous silicon substrate have been reported. Porous silicon (PS) substrate is employed as a template to increase the formation of oxygen vacancies in the ZnO layer and promote suitable grain size conditions for memristance. Morphological and optical properties are investigated using scanning electron microscopy (SEM) and photoluminescence (PL) spectroscopy. The proposed device exhibits a zero-crossing pinched hysteresis current-voltage (I-V) curve characteristic of memristive systems.
RESUMO
UNLABELLED: The monocyte locomotion inhibitory factor (MLIF) is a heat-stable pentapeptide produced by Entamoeba histolytica in culture. This factor displays several anti-inflammatory properties (i.e., inhibition of locomotion and respiratory burst in monocytes, reduction of skin hypersensitivity and delay of mononuclear cells in human Rebuck skin windows) with inhibition of adhesion molecules, chemokines, and other genes including interleukin-1ß (IL-1ß). In animal models, it reduces carragenin-induced inflammation and delays the inflammatory process in murine collagen-induced arthritis (CIA). OBJECTIVES: To test, in vitro, the anti-inflammatory capacity of MLIF on a promonocytic human cell line (U-937) cells and peripheral blood mononuclear cells (PBMC) from healthy subjects and from patients with rheumatoid arthritis (RA). MATERIAL AND METHODS: IL-1ß gene expression was evaluated in cell cultures either in the presence of MLIF, lipopolysaccharide (LPS), or both. Relative gene expression and immunoreactivity of IL-1ß were assayed in cells and supernatants, respectively. RESULTS: Amebic peptide was able to down-regulate LPS-induced expression of IL-1ß, in U-937 cells without a detectable effect upon the bioavailability of the cytokine. In similar culture conditions, MLIF was capable to down-regulate baseline and LPS-induced expression of IL-ß only in PBMC from patients with RA. Peptide effect on immunoreactivity of IL-1ß was not statistically significant. CONCLUSIONS: MLIF exerts, in primed cells, exquisite anti-inflammatory properties that deserve to be explored mechanistically.