Potencial antioxidante do extrato de campomanesia sessiliflora (guabiroba verde) e modulação sobre a hidrólise de nucleotídeos em soro de ratos

CNPq - Conselho Nacional de Desenvolvimento Científico e TecnológicoTrabalho de Conclusão de Curso (Graduação)A hipertensão arterial sistêmica (HAS) é um problema mundial de saúde. A sinalização purinérgica tem se demonstrado bastante promissora como alvo de tratamento dessa patologia, uma vez que regula processos importantes que podem ser modulados a fim de restabelecer a homeostase do fluxo sanguíneo. A Campomanesia sessiliflora, pertence à família Myrtaceae, a qual já tem sido vastamente empregada na medicina popular. Objetivos: obter o extrato metanólico das folhas de Campomanesia sessiliflora, determinar sua atividade antioxidante, o conteúdo de flavonoides e de fenóis totais e avaliar o efeito do extrato sobre as hidrólises de ATP, ADP e AMP em soro de ratos. O extrato das folhas de guabiroba foi obtido utilizando-se metanol como solvente. O conteúdo de fenóis totais, flavonoides e a determinação da atividade antioxidante foram realizados por métodos colorimétricos, bem como a determinação da atividade enzimática. O rendimento do extrato metanólico foi de 12,6%, o conteúdo de fenóis totais resultou em 62,30 ± 2,42 mg Eq AG/ g e o de flavonoides foi de 16,74 ± 1,3 mg Eq quercetina/ g. Além disso, o extrato exibiu alta atividade antioxidante, sendo capaz de inibir o radical DPPH• em 57,12%, 69,37% e 90,2% nas concentrações de 200, 250 e 500 µg/ mL, respectivamente. Não foram observados resultados significativos para a modulação das atividades de hidrólise dos nucleotídeos pelo extrato. Embora a Campomanesia sessiliflora não tenha demonstrado modulação significativa na sinalização purinérgica em soro, ela exibiu potente atividade antioxidante e grande conteúdo de flavonoides, cujo potencial farmacológico deve ser melhor aprofundado tendo em vista as ações terapêuticas atribuídas a essas moléculas

New ASPN high efficiency treatment of ASTM M2 steel

Plasma nitriding treatments are applied to achieve excellent surface properties on steel parts and tools. Active screen plasma nitriding (ASPN) does not have the defects presents in direct nitriding plasma treatments (DCPN). However, ASPN require much longer processing times to develop surface layers as deep as those of DCPN. This work presents the development of a biased ASPN treatment system, to investigate the possibility of achieving greater efficiency. The treatments were performed on ASTM M2 steel samples using the same processing parameters in 4 different configurations: DCPN, ASPN and 2 active screen plasma nitriding with biased specimens voltage: one was called "bright bias", because biased voltage is high enough to develop a plasma glow on the samples, and the other "dark bias", where no plasma glow sheath is seen on the samples. The active screen dark biased treatment presented the best results. These results could be understood by the electromagnetic field generated by the bias source promoting the deposition of nitrogen ions on the surface of the part being treated. Therefore, it was demonstrated that the use of dark bias voltage in the active screen treatment in larger reactors is fundamental to achieve good nitriding results in smaller times

Comparison of surface properties modification by direct and active screen plasma nitriding of an ASTM M2 high-speed steel in a nitrogen rich gas mixture

The active screen plasma nitriding technique has been studied in recent years as a method to optimize surface properties in steel components, avoiding the negative effects caused in the conventional Direct Current plasma treatments. In this study, ASTM M2 high-speed tool steel samples were plasma nitrided with and without the use of the active screen, in order to compare the surface properties developed by each technique. The treatments were carried out at 500 °C, with the gas mixture of 76 vol.% N2 + 24 vol.% H2 , for 4 and 8 h. The active screen used was built with an expanded sheet of 304 stainless steel. The results were evaluated through optical microscopy, X-ray diffraction, and microhardness measurements. The samples were subjected to dry ball-on-flat tribological tests and the wear tracks were verified by 3D optical interferometry. The active screen use provided the formation of thinner layers, however, avoided the formation of brittle phases, resulting in the lowest wear volumes observed, up to 10 times less than the other analyzed conditions (nitrided and non-nitrided samples).A técnica de nitretação com tela ativa vem sendo estudada nos últimos anos como uma maneira de otimizar propriedades superficiais de componentes de aço, evitando os efeitos negativos provocados nos tratamentos a plasma convencionais de corrente contínua. Neste estudo, amostras do aço rápido ASTM M2 foram submetidas a tratamentos de nitretação a plasma com e sem a utilização da tela ativa, a fim de comparar as propriedades superficiais proporcionadas por cada técnica. Os tratamentos foram executados em 500 °C, com a mistura gasosa de 76% N2 + 24% H2 , durante 4 e 8 horas. A tela ativa utilizada foi construída utilizando chapa expandida de aço inoxidável AISI 304. Os resultados foram avaliados através de microscopia ótica, difração de raios-X e medidas de microdureza. As amostras foram submetidas a ensaios tribológicos do tipo esfera-sobre-plano a seco e as trilhas de desgaste foram verificadas por interferometria ótica 3D. A utilização da tela ativa proporcionou a formação de camadas menos profundas, porém, evitou a formação de fases frágeis, resultando nos menores volumes desgastados observados, até 10 vezes menor que as outras condições analisadas (amostras nitretadas e não-nitretada)

Project-Based Learning: a strategy for teaching integral differential calculus for engineering students in a school in Brazil

One of the problems that concerns engineering courses in Brazil is the students low level of motivation in regarding the type of teaching and, as a consequence, low academic performance. This article encourages the introduction of active methods in Engineering teaching, emphasizing the methodologies of Project Based Learning. The approach used was proposing a project for students to analyze important aspects in the production of cylindrical cans. The students applied calculus concepts and developed a model for the optimal dimensions of the cylinder and the utilization of the plates used. Characteristics of two materials used in the manufacture of these cans (tinplate and aluminum) were also gotten. Such aspects are relevant for both environmental sustainability and production costs. Concepts of application of derivatives and Fermat\u27s theorem were used, learned in the discipline of Differential and Integral Calculus, in order to obtain the maximum and minimum values of an established function which relates the dimensions of the can and the amount of material needed. The dimensions obtained theoretically proved to be close to the real values found in cans available on the market. After analyzing the resistance to corrosion, the cost, the decomposition time and the mechanical resistance, it was concluded that the most appropriate material for the production of cans was the tinplate. In this context, teaching with Project Based Learning methodologies may contribute to innovative teaching practices in the training of engineering professionals, overcoming the limitations of traditional teaching methods

Response of a DIN 18MnCrSiMo6-4 continuous cooling bainitic steel to different plasma nitriding gas mixtures

Continuous cooling bainitic steels has been widely used in industrial processes owing to its excellent mechanical properties and toughness. Although the surface properties of them are acceptable for many purposes, for their use in mechanical components like gears, it is necessary to improve their surface properties. Plasma nitriding treatments was carried out of a DIN 18MnCrSiMo6-4 steel at 500 °C, with three different nitrogen gas composition: 76, 24 and 5 vol.% nitrogen in hydrogen, for 3, 6 and 9 hours. The surfaces were characterized concerning the microstructure, microhardness, fracture toughness, nitrogen concentration and carbon composition, phase composition and residual stress states. Based on the results presented, layer growth constants (k) for different nitrogen gas composition was determined. The carbon profiles of samples indicate that there was decarburization during the plasma nitriding. The nitrided samples with thicker compound layers presented a fracture behavior dominated by the formation of Palmqvist cracks. X-ray phase analysis indicated the formation of biphasic compound layer on the surface of all nitrided samples with 76 and 24 vol.% nitrogen, while the nitrided samples with 5 vol.% nitrogen indicated the formation of monophasic compound layer. The diffusion zone presented compressive residual stresses with highest values near the surface

Data fusion approach for eucalyptus trees identification

UIDB/00066/2020 DSAIPA/AI/0100/2018Remote sensing is based on the extraction of data, acquired by satellites or aircrafts, through multispectral images, that allow their remote analysis and classification. Analysing those images with data fusion techniques is a promising approach for identification and classification of forest types. Fusion techniques can aggregate various sources of heterogeneous information to generate value-added maps, facilitating forest-type classification. This work applies a data fusion algorithm, denoted FIF (Fuzzy Information Fusion), which combines computational intelligence techniques with multicriteria concepts and techniques, to automatically distinguish Eucalyptus trees from satellite images. The algorithm customization was performed with a Portuguese area planted with Eucalyptus. After customizing and validating the approach with several representative scenarios to assess its suitability for automatic classification of Eucalyptus, we tested on a large tile obtaining a sensitivity of 69.61%, with a specificity of 99.43%, and an overall accuracy of 98.19%. This work demonstrates the potential of our approach to automatically classify specific forest types from satellite images, since this is a novel approach dedicated to the identification of eucalyptus trees.publishersversionpublishe

Bibliometric Study of Publications on Eruption of Deciduous and Permanent Teeth

Objective: To perform a bibliometric analysis on deciduous and permanent eruption publications to discuss the global trends and prospects on the topic. Material and Methods: A systematic search was conducted on the Scopus database. The characteristics of the publications, including co-cited authors, organizations, countries, most cited sources, publications, and keyword co-occurrence, were analyzed using VOSviewer software version 1.6.18. Results: After applying exclusion criteria, 492 studies were included in the analysis. The majority of research centers were located in Europe. "Archives of Oral Biology" emerged as the most frequently cited journal. The United States and Brazil were the most frequently cited countries in the publications. Notable co-authors included Kuchler E. C. and Hägg U. The most frequently cited keywords were associated with oral pathologies, tooth development, odontogenesis, and genetics. The most recent papers were published in journals focused on oral diseases. Conclusion: This bibliometric analysis highlights that the future of research in this field is likely to be focused on the investigation of tooth eruption in both deciduous and permanent teeth, with an emphasis on genetics, tooth development, timing of tooth eruption, and syndromic conditions. While well-accepted in the fields of Pediatrics and Orthodontics, there is a growing interest in this topic within oral biology and pathology journals in the Americas, with the United States and Brazil leading in terms of publications and citations

Acionador automático para irrigar plantas

Despite the massive demand of water for plant irrigation, there are few devices being used in the automation of this process in agriculture. This work evaluates a simple controller to water plants automatically that can be set up with low cost commercial materials, which are large-scale produced. This controller is composed by a ceramic capsule used in common domestic water filters; a plastic tube around 1.5 m long, and a pressostate used in domestic washing machines. The capsule and the pressostate are connected through the tube so that all parts are filled with water. The ceramic capsule is the sensor of the controller and has to be placed into the plant substrate. The pressostate has to be placed below the sensor and the lower it is, the higher is the water tension to start the irrigation, since the lower is the pressostate the higher is the water column above it and, therefore, the higher is the tension inside the ceramic cup to pull up the water column. The controller was evaluated in the control of drip irrigation for small containers filled with commercial organic substrate or soil. Linear regressions explained the relationship between the position of pressostate and the maximum water tension in the commercial substrate (p < 0.0054) and soil (p < 0.0001). Among the positions of the pressostate from 0.30 to 0.90 m below the sensor, the water tension changed from 1 to 8 kPa for commercial substrate and 4 to 13 kPa for the soil. This simple controller can be useful to grow plants, applying water automatically in function of the water tension of the plant substrate.A despeito da enorme demanda por água na irrigação de plantas, existem poucos aparelhos para automação deste processo sendo usados na agricultura. Avaliou-se um acionador automático para irrigação, o qual pode ser confeccionado com materiais comerciais de baixo custo, pois são produzidos em larga escala. Este acionador é composto por uma cápsula cerâmica usada em filtros de água domésticos; um tubo plástico com cerca de um metro e meio de comprimento e um pressostato de máquinas de lavar roupas domésticas. A cápsula e o pressostato são conectados pelo tubo de forma que todo o espaço interno seja preenchido com água. A cápsula é o sensor do acionador e deve ser posicionada dentro do substrato das plantas. O pressostato deve ser posicionado abaixo do sensor e quanto mais baixo ele estiver, maior é a tensão da água que aciona a irrigação, pois quanto mais baixo estiver o pressostato, maior é a coluna de água acima do mesmo e, portanto, maior é a tensão na cápsula cerâmica para puxar para cima a coluna de água. O acionador foi avaliado no controle da irrigação por gotejamento em pequenos potes preenchidos com substrato orgânico comercial ou solo. Regressões lineares explicaram a relação entre a posição do pressostato e a tensão máxima no substrato comercial (p < 0,0054) e no solo (p < 0,0001). Entre as posições do pressostato de 0,30 a 0,90 m abaixo do sensor, a tensão da água variou de 1 a 8 kPa para o substrato comercial e de 4 a 13 kPa para o solo. Este simples acionador pode ser útil para cultivar plantas, aplicando água automaticamente em função da tensão da água no substrato das plantas

Response of a DIN 18MnCrSiMo6-4 continuous cooling bainitic steel to plasma nitriding with a nitrogen rich gas composition

The use of continuous cooling bainitic steels can provide a more energy efficient manufacturing route. However, for their use in mechanical components like gears, it is necessary to improve their surface properties without impacting the core properties to guarantee reliable mechanical performance. The effect of temperature and time on the plasma nitriding response of a DIN 18MnCrSiMo6-4 steel was investigated. The plasma nitriding was performed for 3, 6 and 9 hours, at 400, 450, 500 and 550 °C, using a gas mixture composed of 76 vol.% nitrogen and 24 vol.% hydrogen. Samples were characterized before and after plasma nitriding concerning the microstructure, hardness and microhardness, fracture toughness, phase composition and residual stress states. Based on the results presented, layer growth constants (k) for different temperatures was determined. Moreover, it could be found that 500 °C gave the best results investigated here, as higher temperature took to core and surface hardness decrease. The nitrided samples with thicker compound layers presented a fracture behavior dominated by the formation of Palmqvist cracks. X-ray phase analysis indicated the formation of biphasic compound layer on the surface of all nitrided samples. The diffusion zone presented compressive residual stresses with highest values near the surface