São Paulo Federal Institute of Education, Science and Technology

About: São Paulo Federal Institute of Education, Science and Technology is a education organization based out in São Paulo, Brazil. It is known for research contribution in the topics: Context (language use) & Computer science. The organization has 1707 authors who have published 2374 publications receiving 11333 citations.

Growth mechanisms of Ca- and P-rich MAO films in Ti-15Zr-xMo alloys for osseointegrative implants

Abstract: In this study, a micro-arc oxidation treatment was applied to Ti-15Zr-xMo (x = 0, 5, 10 and 15 wt%) alloys to produce porous oxide layers enriched with bioactive ions (calcium and phosphorus) for use as osseointegrative implants. Biocompatibility studies, namely metabolic activity, mineralization and differentiation studies were conducted with human osteoblastic cell line SAOS-2. A typical porous coating was obtained in all samples, with similar morphologies and thicknesses, which were found to be dependent on the maximum applied voltage. Calcium and phosphorus ions were incorporated into the films, as indicated by EDX analysis. Chemical analyses indicated that the films were composed preferentially of Ti and Zr oxides. XRD patterns revealed mostly substrate Ti phases. However, cross-sectional TEM imaging and automated phase and orientation mapping showed distinct amorphous and nanocrystalline regions within the films, with a higher fraction of Ca atoms incorporated in the outer layer. After immersion in Hanks' Balanced Salt Solution (HBSS) for seven days, small amounts of calcium phosphate precipitates were observed at the surface of all samples which were confirmed by ICP-AES measurements, indicating that the MAO treatment possibly introduced a considerable bioactive response in the samples. Biological results indicate that Ti-15Zr-15Mo MAO-treated surfaces are biocompatible and induce a higher osteoblasts viability and mineralization. The combination of porous structure and bioactive composition of the oxide layers can be suitable for use as advanced biomedical implants with osseointegration ability.

Deep Feature-Based Classifiers for Fruit Fly Identification (Diptera: Tephritidae)

Abstract: Fruit flies has a big biological and economic importance for the farming of different tropical and subtropical countries in the World. Specifically in Brazil, third largest fruit producer in the world, the direct and indirect losses caused by fruit flies can exceed USD 120 million/year. These losses are related to production, the cost of pest control and export markets. One of the most economically important fruit flies in the America belong to the genus Anastrepha, which has approximately 300 known species, of which 120 are recorded in Brazil. However, less than 10 species are economically important and are considered pests of quarantine significance by regulatory agencies. The extreme similarity among the species of the genus Anastrepha makes its manual taxonomic classification a nontrivial task, causing onerous and very subjective results. In this work, we propose an approach based on deep learning to assist the scarce specialists, reducing the time of analysis, subjectivity of the classifications and consequently, the economic losses related to these agricultural pests. In our experiments, five deep features and nine machine learning techniques have been studied for the target task. Furthermore, the proposed approach have achieved similar effectiveness results to state-of-art approaches.

Hydrogen peroxide production regulates the mitochondrial function in insulin resistant muscle cells: Effect of catalase overexpression

Abstract: The mitochondrial redox state plays a central role in the link between mitochondrial overloading and insulin resistance. However, the mechanism by which the ROS induce insulin resistance in skeletal muscle cells is not completely understood. We examined the association between mitochondrial function and H2O2 production in insulin resistant cells. Our hypothesis is that the low mitochondrial oxygen consumption leads to elevated ROS production by a mechanism associated with reduced PGC1α transcription and low content of phosphorylated CREB. The cells were transfected with either the encoded sequence for catalase overexpression or the specific siRNA for catalase inhibition. After transfection, myotubes were incubated with palmitic acid (500μM) and the insulin response, as well as mitochondrial function and fatty acid metabolism, was determined. The low mitochondrial oxygen consumption led to elevated ROS production by a mechanism associated with β-oxidation of fatty acids. Rotenone was observed to reduce the ratio of ROS production. The elevated H2O2 production markedly decreased the PGC1α transcription, an effect that was accompanied by a reduced phosphorylation of Akt and CREB. The catalase transfection prevented the reduction in the phosphorylated level of Akt and upregulated the levels of phosphorylated CREB. The mitochondrial function was elevated and H2O2 production reduced, thus increasing the insulin sensitivity. The catalase overexpression improved mitochondrial respiration protecting the cells from fatty acid-induced, insulin resistance. This effect indicates that control of hydrogen peroxide production regulates the mitochondrial respiration preventing the insulin resistance in skeletal muscle cells by a mechanism associated with CREB phosphorylation and β-oxidation of fatty acids.