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Síntese de complexos de Mg(II), atividade antioxidante e citotóxica
(Universidade Federal de São Carlos, 2021-03-09) Santos, Josenilton de Jesus; Carlos, Rose Maria; https://lattes.cnpq.br/1589143355309943; https://lattes.cnpq.br/8905293463487217
The objective of this work was to develop metal complexes containing natural products that have antioxidant activity to be applied in the cosmetics sector. For that, 3 [Mg(phen)2PN]+ metal complexes were synthesized and characterized, where phen = 1,10-phenanthroline and PN are the natural products: caffeic acid (caf), cinnamic (cin) and cinnamic 4-dimethylamino acid (dmaca). The characterizations of ligands and complexes were carried out by electron injection mass spectrometry, UV-Vis, infrared, and 1H NMR spectroscopic techniques. The antioxidant activity of the compounds was investigated in relation to electron and hydrogen atom transfer using the free radical DPPH. In these experiments, only free caffeic acid and its [Mg(phen)2(caf)]+ complex showed antioxidant activity in relation to DPPH. An indirect test to determine the ability of superoxide dismutase (SOD) to inhibit the reactions induced by the superoxide radical anion was performed. Using the riboflavin reduction method in the presence of methionine and induced by 420 nm light irradiation, the antioxidant capacity of the complexes in relation to the superoxide radical was evaluated. In this study, antioxidant activity was observed for the phenolic compounds caffeic acid (caf) and cinnamic 4-dimethylamino acid (dmaca), as well as for their respective [Mg(phen)2(caf)]+ and [Mg(phen)2(dmaca)]+ complexes, with the highest inhibition percentages of O2.- were observed for the complexes. The antioxidant activity in relation to singlet oxygen (1O2) was performed using the paramagnetic resonance (EPR) technique. For the [Mg (phen)2(caf)]+ complex the IC50 value was 5.0 μg mL-1 and for the [Mg(phen)2(dmaca)]+ the IC50 value was 7.5 μg mL-1. The complexes did not inhibit the activity of the enzyme acetylcholinesterase. MTT assays to estimate the cytotoxicity of complexes in A375 human melanoma cells indicated IC50 around 6 μM for the 3 complexes studied.
Caracterização do desgaste do rebolo na retificação de insertos de metal duro
(Universidade Federal de São Carlos, 2021-03-09) Rodrigues, Aristóteles Guido; Ventura, Carlos Eiji Hirata; https://lattes.cnpq.br/1689198421096127; https://lattes.cnpq.br/7952861067827367
The cutting tool manufacturing industry constantly seeks to improve its products, due to the high competition in this sector. In this scenario, cemented tungsten carbide cutting inserts stand out for their wide application, related to their excellent cost-benefit ratio in the machining of diverse types of metals. Thus, an increasing knowledge of their manufacturing process variables and their effects is required, being the grinding operation a fundamental step in the search for high efficiency of cutting inserts, as it is responsible for providing the final dimensions as well as appropriate surface and edge quality. Within this context, the present work aims to characterize the wear of a diamond grinding wheel during grinding of cemented tungsten carbide inserts and to assess its effects on the insert surface characteristics with the increase in total material removal volume. For this, a resin bonded wheel with diamond grains D46 was applied and the normal and tangential force components were measured during the process. In addition, the grain protrusion in the abrasive grinding layer, the insert surface and edge roughness were analyzed. The obtained results revealed an initial reduction in the grain protrusion and the consequent increase in the grinding forces with the increase in the volume of removed material. With the grinding of larger volumes, however, the occurrence of self-sharpening was also observed, which led to increased grain protrusion and reduced forces. This phenomenon contributed to the increase in the number of active edges in the abrasive layer and caused a reduction in the insert surface roughness. Little or no variation in edge roughness was identified.
Terras Indígenas ou recursos naturais para o capital? o papel do Estado nos conflitos territoriais no Alto Xingu
(Universidade Federal de São Carlos, 2021-03-09) Souza, Elierson Fernando de; Franca, Gilberto Cunha; https://lattes.cnpq.br/0983946781650048; https://lattes.cnpq.br/9584864773213070
This paper aims to analyze the role of the Brazilian State in territorial conflicts in the Xingu basin. To do so, we will make a geographic cut focusing on the Alto Xingu region, state of Mato Grosso, to present the problems present in this region that generate conflicts between the peoples of the Xingu Indigenous Park and the Soybean-producing Landowners. By using the epistemological basis of David Harvey's theory on the production of capitalist space in the 21st century, which, therefore, is a theoretical framework aimed at critical analysis on the process of capitalist territorialization in globalization, we will have a work related to political geography, reason why the territory will be the main category of geographic analysis applied to the study in question.
O uso de treino informatizado para ensinar professores a conduzirem Avaliação de Preferência de Escolha Pareada
(Universidade Federal de São Carlos, 2021-03-09) Macedo, Viviane Alves de; Goyos, Antônio Celso de Noronha; https://lattes.cnpq.br/3407008711535651; https://lattes.cnpq.br/0512314068392954
Knowing a child's preferences can be an essential strategy to motivate the child to perform tasks in the classroom context. For this, it is important that teachers know how to apply tests to identify these items of preference, especially in children with delayed language development. The present research aims to develop a teaching assessment and test its effectiveness by training teachers in conducting a Paired-Choice Preference Assessment based on Animated Auto-Instructional Video. Two studies were carried out, both developed with Special Education teachers and carried out within a public school, with three participants for each study. In the first, it was tested in a pre and post-test design, in three different conditions (Condition A, Condition B and Condition C), if the Independent Variables (IV), called: 1) Animated Auto-Instructional Video and 2) Instructional Guide (IG), were responsible for modifying the Dependent Variable (DV), called: Conducting a Paired-Choice Preference Assessment. The performance results of the three participants demonstrated the effectiveness of the training performed through Animated Videos. The difficulty of all of them was evidenced in the performance, especially in what concerns the measurement and control of time by means of the stopwatch. The purpose of the second research was to teach teachers through Animated Auto-Instructional Videos (IV), using a multiple baseline design between subjects to measure, in repeated sessions, whether the Dependent Variable (DV), called: Conducting a Paired-Choice Preference Assessment, remains stable throughout the sessions. Three Special Education teachers who work in the Multifunctional Resource Room participated in this study. The repertoire of each subject was evaluated in three baseline sessions, applied before the manipulation of the variables. After the intervention, the repertoires of these participants were again evaluated in three sessions held under the same conditions as the baseline sessions applied previously. The results showed that all participants performed better in the intervention sessions. The performance related to the control and measurement of time using the stopwatch was superior to the performance presented in the first study.