Navegando por Data de Publicação, começando com "2018-10-26"

Filtrar resultados por ano ou mês

Agora exibindo 1 - 9 de 9

Estudo da resistência à corrosão intergranular do aço inoxidável austenítico f138 - perspectiva de desempenho após Deformação Plástica Severa (DPS)
(Universidade Federal de São Carlos, 2018-10-26) Rodrigues, Rodolfo de Souza; Kliauga, Andrea Madeira; https://lattes.cnpq.br/3527528295399928; https://lattes.cnpq.br/2760387813535332
Austenitic stainless steels are widely used in heating and cooling circuits of thermoelectric and nuclear power plants (NPP) in the storage and reprocessing of nuclear fuels, mainly because they have good processability, high resistance to corrosion and creep. In particular in thermonuclear applications there is, however, the trouble of swelling caused by the nucleation of He voids and bubbles within the irradiated material and the increased sensitivity to intergranular corrosion due to the acceleration by diffusion of alloying elements in the material. Using severe plastic deformation (DPS) by the equal channel angular pressing (ECAP), an increase in the bondary area can be achieved as well as an increase in the density of dislocation enhancing He trapping in these regions. In relation to intergranular corrosion, the mechanism acting in most cases is the sensitization caused by precipitation in boundary grain of chromium-rich phases such as Cr23C6 and intermetallic precipitates. Increased plastic deformation (above 15%) can accelerate the sensitization process in austenitic stainless steels. In order to evaluate the effect of DPS on the corrosion resistance in oxidizing media, the ASTM 262 Practice C test was performed on a ASTM F138 steel after solubilization (1h at 1100oC), sensitization (240h at 850oC) and ECAP (7 passes at 300oC). Microstructural characterization was performed to analyze the sensitization process and to verify the corrosion mechanisms using Optical Microscopy (OM), Scanning Electron Microscopy (SEM) together with X-ray Energy Dispersion Spectroscopy (EDS), Transmission Electron Microscopy (TEM), Mapping of crystallographic orientation by diffraction patterns in MET, X-ray Diffraction (DR-X) and X-ray Excited Photoelectron Spectroscopy (XPS). It was verified that while the sensitized material underwent intergranular corrosion the solubilized and ECAP material were subjected to gerenal corrosion. The mass loss in HNO3 was larger for general corrosion than for intergranular corrosion. The passive film of the ECAP sample contained more Chromium III and Molybdenum than in the solubilized sample, and therefore presented higher resistance to corrosion in the HNO3 medium. The sensitized material presented precipitates with high concentration of chromium and molybdenum leaving the surrounding regions more susceptible to intergranular corrosion and by pites. The film formed on the surface of the sensitized samples presented higher amount of the Chromium VI oxide in relation to the solubilized samples and ECA7x. This oxide is less resistant to acid corrosion than Chromium III oxide. The passive film of the ECAP sample contained more Chromium III and Molybdenum than in the solubilized sample, and therefore presented higher resistance to corrosion in the HNO3 medium.
Investigação dos mecanismos neurobiológicos envolvidos nas propriedades reforçadoras, sensibilização locomotora e reinstalação da autoadministração de etanol
(Universidade Federal de São Carlos, 2018-10-26) Bianchi, Paula Cristina; Cruz, Fábio Cardoso; https://lattes.cnpq.br/4804337113083801; Planeta, Cleopatra da Silva; https://lattes.cnpq.br/2514762545280942; https://lattes.cnpq.br/1169254558226835
Alcohol is the most consumed drug in Brazil and in many other countries in the world. The high rate of relapse in alcohol-dependent individuals remains a central challenge for treating alcoholism. Several studies in human and animal models of addiction show that environmental stimuli associated with previous drug use can provoke relapse to drug use. However, the neurobiological mechanisms involved in the alcohol relapse induced by environmental stimuli are not fully understood. Recent studies have been demonstrated that the synaptogenic effect of matricellular protein Hevin can promote striatal neuroplasticity that can modulate motivational properties of drugs. Despite that, the role of Hevin in alcohol addiction related behaviors has not been investigated. In the present study, we investigated the participation of pre-limbic cortex (PL); orbitofrontal cortex (OFC), and nucleus accumbens (NAc) in the context-induced reinstatement of alcohol-seeking in rats. We also evaluated the effect of Hevin inhibition in astrocytes or parvalbumin interneurons (PV) in the striatum on ethanol consumption, ethanol-induced conditioned place preference (CPP) and locomotor sensitization in mice. Our results demonstrated that: a) there were no differences between male and female rats in the reinstatement of alcohol-seeking behavior; b) re-exposure to the drug-context reinstated alcohol-seeking and increased Fos expression in the OFC, PL and NAc core and shell; c) reversible inactivation of the OFC or NAc core attenuated context-induced reinstatement of alcohol-seeking; d) there was more activation of the PL – NAc core pathway in the animals exposed to the drug-context, compared to those that were exposed to the extinction-context; e) inhibition of astrocytic Hevin into NAc did not alter ethanol consumption, but decreased alcohol-induced CPP; f) inhibition of astrocytic and neuronal Hevin in the dorsal striatum decreased locomotor sensitization induced by alcohol; and g) repeated alcohol injections in mice increased the volume of dendritic compartments of PV interneurons in the dorsal striatum.
Efeitos do contaminante emergente triclosan sobre a função cardiorespiratória do matrinxã, Brycon amazonicus, em normóxia e durante hipóxia gradual
(Universidade Federal de São Carlos, 2018-10-26) Martins, Nícolas Fernandes; McKenzie, David John; https://lattes.cnpq.br/0281731956436645; Kalinin, Ana Lúcia; https://lattes.cnpq.br/5493936744279888; https://lattes.cnpq.br/2969192784846566
Many organic compounds present in bodies of water, called emerging contaminants, are not yet contemplated in Brazilian environmental legislation. Such compounds need to be evaluated for their high toxicity to living organisms, causing serious problems for ecosystems, animal and human health. Among these compounds, widely used, is triclosan (TCS). The increasing use of TCS by the industry and a variety of common household products, including detergents, toothpastes, soaps, among others, results in the release of large and increasing amounts of this compound in water bodies, which can affect the health and survival of organisms aquatic Brazilian legislation has established a maximum TCS concentration of 0.3% for personal care products, cosmetics and perfumes, but there is no established limit for maximum permissible concentrations in the different water bodies. Despite the concern with such contaminant, few works are addressing its physiological effects on aquatic organisms, particularly fish. The present study evaluated the effect of TCS on cardiorespiratory function in vivo and on the expression of cardiac proteins involved in the management of cardiac calcium of Brycin amazonicus. Among the main findings, the present study showed that: a) in the presence of TCS the water does not reach 100% saturation with O2; b) TCS not only reduces the metabolic rate but also increases the critical O2 uptake, reducing the ability to keep O2 uptake constant and, consequently, reducing the chances of survival in hypoxic environments; c) the ventilatory requirement is significantly increased by the TCS, showing a significant decrease in the efficiency of the gills in the exchange of O2 besides increasing the energy expenditure for the gas exchange; d) TCS had a depressant effect on heart rate and increased expression of L-type calcium channels and Na + / Ca 2+ exchanger. Together, the results obtained in the present study show that the TCS, even in low concentrations and in short exposures (96h), decreases respiratory capacity of the species and interferes in the management of cardiac calcium. The depressant effect of cardio-respiratory function in vivo as well as changes in the expression of proteins involved in the cardiac excitation-contraction coupling of matrinxã reinforce the need not only for reassessment of the use of SCC in consumer products but also for the establishment of maximum limits waters for human consumption and conservation of aquatic life.
Estudo empírico-teórico de compósitos baseados em polímeros condutores para conversão e armazenamento de energia
(Universidade Federal de São Carlos, 2018-10-26) Gonçalves, Roger; Souza, Ernesto Chaves Pereira de; https://lattes.cnpq.br/1505400360366643; https://lattes.cnpq.br/5949704693295518
The fast obsolescence of still functional devices causes an extensive e-waste generation and an exacerbated natural resources consumption for the manufacture of new products. In this sense, the development of abundant materials devices-based development, coupled with greater efficiency of conversion, use and storage of energy, are fundamental. Therefore, this thesis presents fundamental studies useful for understanding the behavior of these materials, as well as their applications. The polypyrrole (PPy) electronic structure and growth kinetics were studied using EIS and STM, obtaining important results regarding the exponential increase of the electroactive area during the polymer synthesis, as well as the behavior of its quasi-particles due to electrochemical doping. In addition, it was studied the application of a 2d polymer with graphene-like properties as its possible substitute. This material, called carbon nitride (C3N4), is widely known in the catalysis area, but still poorly explored in electrochemistry. Conductive polymer composites were studied as active materials for the conversion and storage of clean and inexpensive energy. As a result, it was obtained that this material is promising for application in metal-free capacitors, having a great cycling, above 5 K cycles, also increasing the lifespan of a supercapacitor based on PPy, besides obtaining the unprecedented value of 3.0 kF g-1. As for energy conversion, this material demonstrated better compatibility with polythiophene derivatives, promoting better photocurrent in less cathodic potentials, 3 times increase, versus only 2 times increase for reduced graphene oxide in the same conditions. It is concluded, therefore, that carbon nitride is an excellent material for applications in devices based on conductive polymers.
Estudo da viabilidade técnica do reaproveitamento de altos teores de fibras de poli(para-aramida) como reforço mecânico em poliamida 66
(Universidade Federal de São Carlos, 2018-10-26) Bello, Thômas Scarassati; Costa, Lidiane Cristina; https://lattes.cnpq.br/8246109223926480; Bettini, Sílvia Helena Prado; https://lattes.cnpq.br/3687551763124327; https://lattes.cnpq.br/2242339366610034
Responsible for an annual demand higher than 70 millions of tons, the poly(para- aramide) fibers are being widely used in the safety, automobilist, aeronautic, and petroleum industries, due to their attractive mechanical, chemical, and thermal properties. However, these fibers cannot be recycled by conventional processes and have to be incinerated or discarded in specific landfills. In order to achieve new applications for their industrial wastes, this project had as main goal the study of technical feasibility in the reuse of high content of poly(para-aramide) fibers as mechanical reinforcement in polyamide 66. The composites were produced by twin-screw extrusion in contents of 10 and 20%, and the screw speed and fiber feed zone were also modified. In addition, the poly(para-aramide) fibers have low adhesion with polymers, and can be even lower with finishing substances from industrial processes. For this reason, the removal of these substances was another condition studied in this work. According to the analyses, a continuous and stable processing is hampered by the high fiber specific volume. The finishing substances removal had a detrimental effect in the process due to increasing on fiber-fiber friction and did not affect the PA66-fiber adhesion. The results have shown that composition and processing conditions did not affect fiber length, which was above the critical length. At the same time, these variables effects were significant on PA66 degradation, which were determinant on composite final properties. It was possible to increase the mechanical properties, and, under certain conditions, it was higher than the commercial composites of PA66/poly(para-aramide).
Avaliação da geração de Hg(0) em reator anaeróbio de fluxo ascendente de ETE
(Universidade Federal de São Carlos, 2018-10-26) Michilini, Larissa Meneghin; Fadini, Pedro Sérgio; https://lattes.cnpq.br/3255060531838427; https://lattes.cnpq.br/1673762564740071
Mercury is a metal of high mobility and toxicity in the environment. The understanding of different aspects about its biogeochemical cycle is of fundamental importance for the management of this global pollutant. Different biotic and abiotic processes are responsible for the transfer between phases, involving the aqueous environment and the atmosphere, causing contaminated aquatic environments and wastewater to also act as emitters and/or remitters of mercury. The current concern about this type of environmental contamination can be attested by the recent Minamata Convention, an agreement signed in 2013 by 140 countries, promulgated by Brazil on August 14, 2018 and which provides the reduction of global mercury emissions. This agreement is both the source control as use restrictions, and Brazil is one of the signatories. The aim of this study was to determine the total mercury (HgT) and Hg(0) in samples of raw sewage and effluent from the Upflow Anaerobic Sludge Blanket Reactor(UASB) of the wastewater treatment plant (ETE-Monjolinho) in the city of São Carlos-SP, using a cold vapor atomic fluorescence spectrometry (CVAFS), a strategy that allows the limits of detection less than ng L-1, which is low enough to allow quantification in any of the matrices of interest. The analyzes were performed between October 2017 and July 2018, in samples collected monthly. The mean concentrations for HgT in ng L-1 were 24.4 ± 9.7 for the station's affluent and 21.9 ± 9.3 for the anaerobic reactor effluent. The results showed that both HgT as well as Hg(0) in the affluent have a correlation with the pH, where in higher pH there is a higher formation of Hg (0) and consequently lower concentrations of HgT and in pH with lower values the tendency is to contain higher concentrations of HgT and lower formation of Hg(0). Correlations between HgT, Hg(0) and dissolved organic carbon (DOC) showed that in the effluent samples as the higher DOC concentration had higher concentration of HgT and lower concentration of Hg(0), supporting the hypothesis of the complexing capacity of organic matter (OM). In the affluent samples this trend was observed more subtly in the results. Regarding to Hg(0), the results obtained in the studied period show that both samples from the station's effluent and reactor effluent mostly immediately reduced the added Hg2+ in the samples, but it was noticed that with the passage of time this tendency has decreased. A reduction capacity of Hg(II) to Hg(0) was found in both the affluent and the reactor's effluent. In the presence of Hg2+ additions, a formation of Hg(0) in the affluent of the order of 29 to 2100 pg L-1 and in the effluent of the order of 23 to 570 pg L-1 was observed. A mass balance that takes into account the annual emission of the WWTP in terms of HgT, points to affluent values of 461 g and 414 g effluent, reaching a removal of 47 g year-1, a value that is partitioned between incorporation to the sludge and emission into the atmosphere after reduction.
Avaliação da produção de biopolímeros pelas cepas bacterianas DsA.N042 e DsA.N049 isoladas de Diabrotica speciosa usando subprodutos industriais
(Universidade Federal de São Carlos, 2018-10-26) Denadae, Bárbara Evelin; Souza, Clovis Wesley Oliveira de; https://lattes.cnpq.br/0781683628437007; Forim, Moacir Rossi; https://lattes.cnpq.br/1234565160573730; https://lattes.cnpq.br/6105870906190947
The global development has enabling the improvement of daily life to human. However, the large production of manufactured materials such as plastics, it has generating environmental unbalanced, especially when they are discarded in an inappropriate manner. Due to this environmental concern, several researches have been carried out looking for materials as same mechanical properties of petroleum-based plastics, however, plastic-environmental friendly. In this context, bioplastics are a good alternative to replacing the petroleum-based plastics since they can be obtained in production processes that are less aggressive to the environment, and easily degraded. Microorganisms such as bacteria are a important source of the bioplastics. They can synthesize them naturally when subjected to specific growth conditions. Another advantage to the use of bacteria in the biotechnological production of (bio) molecules is the use of alternative substrates such as industrial waste (subproducts). Thus, the present study aimed to identify two strains of bacteria from Diabrotica speciosa's gut using 16S rDNA sequencing methodologies, and through fatty acid profiling by gas chromatography-mass spectrometry, as well as to assess their technical and economic viability in the production of biopolymers using industrial subproducts. It was not possible to identify the strains at species level, suggesting new species not described in the literature yet. However, the genera found for the strains in this study were identified as Aureimonas sp. and Delftia sp. The results for the fatty acid profiling showed a wider variety of molecules for Delftia sp. (15 different types) than to Aureimonas sp. (10 types of molecules), although both of they contained palmitic and stearic acid as major compounds. The investigated microorganisms were able of to use glycerol and whey as sources of nutrients to produce biopolymers (polyhydroxyalkanoates), in different concentrations. For Aureimonas sp., the concentration of glycerol and whey that presented the highest yield of biopolymer recovery were 2.0 and 10.0% (v/v), respectively. In its turn, the results for Delftia sp. indicated that 6.0 and 5.0% (v/v) of glycerol and whey, respectively, were the best concentrations evaluated to production of biopolymers in all treatments. The batch using whey at 5.0% (v/v) and the strain of Delftia sp., it produced 38.7% of PHB/cell dry weight, proving the feasibility of the use of the subproducts such as whey to produce biopolymers, as well as the importance to look for microorganisms in new microbiomes.
Saúde mental infantojuvenil e inclusão escolar: desafios, demandas e proposição de formação continuada para professores
(Universidade Federal de São Carlos, 2018-10-26) Lins, Sarah Raquel Almeida; Matsukura, Thelma Simões; https://lattes.cnpq.br/5611215381682164; https://lattes.cnpq.br/9370082703685790
The World Health Organization and recent studies indicate that schools have been receiving students with mental health disorders, but little is known about these children and how teachers have acted with them. Teachers report insecurity to deal with this public and it has been indicated that providing knowledge on child and adolescent mental health (CAMH) to those involved with the school context can be a potent strategy. The present research objective was firstly to understand teachers’ – from primary and secondary levels – daily school routines in dealing with students in psychological distress and, secondly, to offer these teachers a course about CAMH focused on the school context. Study 1 refers to a quantitative, transverse and descriptive research that involved: the identification of the teachers’ conception of children’s mental health, the school reality as well the demands with this public. 164 public school teachers (104 from regular classrooms and 60 from multifunctional-resource classrooms) participated in the study, all of them were linked to the local education network of two medium-sized cities in the state of São Paulo, and they answered two questionnaires. The results revealed that the actions taken by teachers concerning children with mental health disorders are: adaptation of resources, activities and curriculum, dialogue with students and their families, and partnerships between the regular classroom teacher and the resource room teacher. It has been shown that teachers have difficulty speaking about CAMH, due to the little theoretical and practical apparatus in this field. They recognize the importance of knowing more about the subject and suggest themes to compose an educational project in this area, such as: CAMH, intervention strategies and how to present case studies. It discusses the importance of approaching issues related to CAMH in school as a way to support the diversity present in this public with which teachers to achieve both educational and social inclusion. Whereas the Study 2 involved a pilot study on the proposal of a course, application and initial assessment of intervention focusing on the theme “Child Mental Health: Building Knowledge with Multifunctional-Resource Room Teachers”. The course consisted of a 30-hour workload and was developed in eight face-to-face meetings intertwined with out-of-classroom activities, focusing on the daily school routine which distances itself from a medico-centered approach. 53 female teachers who work in multifunctional-resource rooms, linked to the education network of two municipalities in the state of São Paulo, who had participated in Study 1, participated in this second study and answered a questionnaire. The participants evaluated positively the course focusing on the daily practice, and they suggested changes in the way of seeing and relating to the students, treating them with more empathy, understanding and respect. The teachers revealed that they shared the course material with other professionals and showed an interest to delve into the subject. For new course formats, participants proposed a more focused approach onto households as well as the attendance of regular classroom teachers and school managers. Teachers do have both demands and interest in the subject of CAMH and understand that this is a reality of the school routine that has implications in the children’s possibilities of staying, coexisting and learning there. In conclusion, addressing children’s mental health with teachers can contribute to the strengthening of the teacher’s own actions, as well as to the effectiveness of the educational and social inclusion process.
Efeitos da deleção de REST do músculo esquelético sobre a composição corporal e função muscular de camundongos c57bl/6
(Universidade Federal de São Carlos, 2018-10-26) Canevazzi, Gustavo Henrique Rigo; Bergeron, Raynald; Perez, Sergio Eduardo de Andrade; https://lattes.cnpq.br/9408953831211309; https://lattes.cnpq.br/2240791238925455
In order to elucidate the role of skeletal muscle REST (RE1 Silencing Transcription Factor) protein on body composition and muscle functionality, we aimed at evaluating the effects of the specific deletion of REST from skeletal muscle (REST MKO) on mouse morphology, in vivo muscle strength and locomotor activity, and in vitro mechanical properties of isolated fast and slow skeletal muscles. Twenty-five mice were used in our study: 12 wild type (WT; 6 males and 6 females) and 13 REST MKO (8 males and 5 females). After 2 weeks of acclimation, the animals were housed in cages mounted with a running wheel (Day 0) so as to assess the level of voluntary physical activity. Subsequently (Day 4), the animals returned to standard cages and 3 days later (Day 7) grip strength and body composition were assessed. Euthanasia was carried out in the following two to four days (Days 9, 10 and 11; n = 2-4 mice/day) during which slow-twitch soleus (SOL) and fast-twitch extensor digitorum longus (EDL) muscles were collected to assess their mechanical properties during electrical-stimulation protocols. No statistical differences between REST MKO and WT mice were found in female mice. Based on this observation, only the data obtained in male mice were used. REST MKO had no significant effect on body weight, relative grip strength and voluntary physical activity; however, it increased fat (+9%) and decreased lean (-9%) masses significantly. Muscle relative weight was 31% higher in SOL and 19% smaller in the EDL of the REST MKO as compared to WT group (both p<0,05). Evaluation of isolated skeletal muscles mechanical properties during electrostimulation protocols indicated that REST MKO had no effect on maximal relative force in both the SOL and EDL. Regarding the muscle effects, REST MKO promoted greater force development and reduced fatigability in the EDL during the fatigue protocol. In contrast, in SOL muscles the deletion of REST led to a decrease in force production at low frequencies of stimulation and greater fatigue. We have shown that skeletal muscle REST protein seems to be important for the maintenance of lean mass and its loss leads to functional implications in different skeletal muscle tissues.