8 resultados para Total Time

em Universidade Federal do Rio Grande do Norte(UFRN)


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The environmental impact caused by the disposal of non-biodegradable polymer packaging on the environment, as well as the high price and scarcity of oil, caused increase of searches in the area of biodegradable polymers from renewable resources were developed. The poly (lactic acid) (PLA) is a promising polymer in the market, with a large availability of raw material for the production of its monomer, as well as good processability. The aimed of this study was synthesis PLA by direct polycondesation of lactic acid, using the tool of experimental design (DOE) (central composite rotatable design (CCRD)) to optimize the conditions of synthesis. The polymer obtained was characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), viscosimetric analysis, differential scanning calorimeter (DSC) and size exclusion chromatography (SEC). The results confirmed the formation of a poly (lactic acid) semicrystalline in the syntheses performed. Through the central composite rotatable design was possible to optimize the crystallization temperature (Tc) and crystallinity degree (Xc). The crystallization temperature maximum was found for percentage of catalyst around the central point (0,3 (%W)) and values of time ranging from the central point (6h) to the upper level (+1) (8h). The crystallization temperature maximum was found for the total synthesis time of 4h (-1) and percentage of catalyst 0,1(W%) (-1). The results of size exclusion chromatography (SEC) showed higher molecular weights to 0,3 (W%) percent of catalyst and total time synthesis of 3,2h

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The present work has as objective the knowledge of the process of drying of the cephalothorax of shrimp to give support the industry to make possible the use of this byproduct. In this sense, the process conditions in this tray dryer and spouted bed were analyzed. With these results, it was projected and constructs a dryer with specific characteristics for the drying of the cephalothorax. The desorption isotherms were obtained by the dynamic method in the temperatures of 20, 35 and 50º C and in the interval of 10-90% of relative humidity. It was observed that the product in form of powder can be conserved with larger stability for lower relative humidity to 40%. The curves of drying of the dryer of fixed bed were adjusted for the models: single exponential, biparametric exponential and Page. The model biparametric exponential more adequately described all the drying conditions studied. The tests carry out in spouted bed showed high drying rate for the material in the paste form in beds active dynamicly-fluid, provely the necessity of a feeding in shorter intervals of time to increase the thermal efficiency of the process. The projected dryer, be considered the obtained results, it was a rotary dryer with inert bed, feed co-current, discharge in cyclone to take place the separation gas-solid, and feed carry out in intervals of 2 minutes. The optimization of the equipment projected it was accomplished used the complete factorial experimental design 24, this had as independent variables temperature velocity of the air, feed flow rate and encapsulated concentration (albumin), as variables answers the thermal efficiency, the moisture content of obtained powder, total time of test and the efficiency of production of powder in several points of processing. The results showed that the rotary dryer with inert bed can present, also, good results if applied industrially

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In the behavioral paradigm of discriminative avoidance task, both short and long-term memories have been extensively investigated with behavioral and pharmacological approaches. The aim of the present study was to evaluate, using the abovementioned model, the hippocampal expression of zif-268 - a calcium-dependent immediate early gene involved with synaptic plasticity process - throughout several steps of memory formation, such as acquisition, evocation and extiction. The behavioral apparatus consisted of a modified elevaated plus-maze, with their enclosed arms disposed in "L". A pre-exposure to the maze was made with the animal using all arms enclosed, for 30 minutes, followed by training and test, during 10 minutes each. The between sections interval was 24h. During training, aversive stimuli (bright light and loud noise) were actived whenever the animals entered one of the enclosed armas (aversive arm). Memory acquisiton, retention and extinction were evaluated by the percentage of the total time spent exploring the aversive arm. The parameters evaluated (time spent in the arms and total distance traveled) were estimated with an animal tracking software (Anymaze, Stoelting, USA). Learning during training was estimated by the decrease of the time spent exploring the aversive arm. One hour after the beginning of each section, animals were anaesthetized with sodium-thiopental (i.p.) and perfused with 0.9% heparinized saline solution followed by 4% paraformaldehyde. Brains were cryoprotected with 20% sucrose, separeted in three blocks and frozen. The middle block, containing the hippocampus, was sectioned at 20 micro meters in the coronal plane and the resutant sections were submitted to zif-268 immunohistochemistry. Our results show an increased expression of zif-268 in the dentate gyrus (DG) during the evocation and extinction stages. There is a distinct participation of the DG during the memory evocation, but not during its acquisition. Inaddition, all hippocampal regions (CA1, CA3 and DG) presented an increased zif-268 expression during the process of extinction.

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Executive functions are determinant cognitive processes for student success, since they execute and control complex cognitive activities such as reasoning, planning and solving problems. The development of the executive functions performances begin early at childhood going through the adolescence until adulthood, concomitant with the neuroanatomical, functional and blood perfusion changes over the brain. In this scenario, exercise has been considered an important environmental factor for neurodevelopment, as well as for the promotion of cognitive and brain health. However, there are no large scientific studies investigating the effects of a single vigorous aerobic exercise session on executive functions in adolescents. Objective: To verify the acute effect of vigorous aerobic exercise on executive functions in adolescents. Methods: A randomized controlled trial (RCT) with crossover design was used. 20 pubescent from both sexes/gender with age between 10 and 16 years were submitted to two sessions of 30min each: 1) The aerobic exercise session intensity was between 65 and 75% of heart rate reserve, in which 5min for warm-up, 20min at the target intensity and 5min of cool down; and 2) control session watching cartoons. The computerized Stroop test – Testinpacs and trail making test were used to evaluate the inhibitory control and cognitive flexibility assessment respectively, before and after both experimental and control sessions. The reaction time (RT) and number of errors (n) of Stroop test were recorded. The total time (TT) and the number of errors (n) of the trail making test were also recorded. Results: The control session’s RT did not present significant differences in the Stroop test. On the other hand, the exercise session’s RT decreased significantly (p<0.01) after the session. The number of errors made at the Stroop test had no significant differences in control and exercise sessions. The ΔTT of trail making test of exercise session was significantly (p<0.001) lower than the control session’s. Errors made in trail making test did not show significant differences between control and exercise sessions. Additionally, there was significant and positive association among the Stroop test ΔRT of exercise session with xiii chronological age (r= 0.635, p=0.001; r 2 = 0.404, p=0.003) and sexual maturation (rs= 0.580, p=0.007; r 2 = 0.408, p=0.002). Differently, there was no association among the control session ΔRT and chronological age (r= – 0.144, p=0.273; r 2 = 0.021, p=0.545) or sexual maturation (rs= –0.155, p=0.513; r 2 = 0.015, p=0.610). Conclusion: Vigorous aerobic exercise seems to improve acutely executive functions in adolescents. The effect of exercise on inhibitory control performance was associated to pubertal stage and chronological age. In other words, the benefits of exercise were more evident in early adolescence (↑ ΔRT) and its magnitude decreases along the growing up process.

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Lung cancer is one of the most common types of cancer and has the highest mortality rate. Patient survival is highly correlated with early detection. Computed Tomography technology services the early detection of lung cancer tremendously by offering aminimally invasive medical diagnostic tool. However, the large amount of data per examination makes the interpretation difficult. This leads to omission of nodules by human radiologist. This thesis presents a development of a computer-aided diagnosis system (CADe) tool for the detection of lung nodules in Computed Tomography study. The system, called LCD-OpenPACS (Lung Cancer Detection - OpenPACS) should be integrated into the OpenPACS system and have all the requirements for use in the workflow of health facilities belonging to the SUS (Brazilian health system). The LCD-OpenPACS made use of image processing techniques (Region Growing and Watershed), feature extraction (Histogram of Gradient Oriented), dimensionality reduction (Principal Component Analysis) and classifier (Support Vector Machine). System was tested on 220 cases, totaling 296 pulmonary nodules, with sensitivity of 94.4% and 7.04 false positives per case. The total time for processing was approximately 10 minutes per case. The system has detected pulmonary nodules (solitary, juxtavascular, ground-glass opacity and juxtapleural) between 3 mm and 30 mm.

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The environmental impact caused by the disposal of non-biodegradable polymer packaging on the environment, as well as the high price and scarcity of oil, caused increase of searches in the area of biodegradable polymers from renewable resources were developed. The poly (lactic acid) (PLA) is a promising polymer in the market, with a large availability of raw material for the production of its monomer, as well as good processability. The aimed of this study was synthesis PLA by direct polycondesation of lactic acid, using the tool of experimental design (DOE) (central composite rotatable design (CCRD)) to optimize the conditions of synthesis. The polymer obtained was characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), viscosimetric analysis, differential scanning calorimeter (DSC) and size exclusion chromatography (SEC). The results confirmed the formation of a poly (lactic acid) semicrystalline in the syntheses performed. Through the central composite rotatable design was possible to optimize the crystallization temperature (Tc) and crystallinity degree (Xc). The crystallization temperature maximum was found for percentage of catalyst around the central point (0,3 (%W)) and values of time ranging from the central point (6h) to the upper level (+1) (8h). The crystallization temperature maximum was found for the total synthesis time of 4h (-1) and percentage of catalyst 0,1(W%) (-1). The results of size exclusion chromatography (SEC) showed higher molecular weights to 0,3 (W%) percent of catalyst and total time synthesis of 3,2h

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Infections for intestinal parasites are one of the main morbidade causes in humans and, its relationships with socioeconomic levels and hygiene conditions in countries in development are already very established. Many works, even so, they are being accomplished to elucidate the complex interactions among nutrition, these infections and answer imunológica, because it is seen that malnutrition commits the immunity increasing the susceptibilidade for infectious diseases and these for its time can harm the state human nutricional. It is known that sponge helmínticos they stimulate synthesis of IgE so much policlonal as specific for the same ones and that IgA secretora, main imunoglobulina of defense of the mucous ones, can act against protozoa as the Giardia lamblia and against helmintos as Trichuris tichiura and Strongyloides stercorales. Some studies show that the malnutrition energy protéica influences in the production of these answers, but some authors show results divergentes. In this work it was evaluated the levels of total IgE, IgA sérica and secretora, contagem of sanguine eosinófilos, levels of proteins séricas and state nutricional, in 103 children of low socioeconomic level, to discover a correlation between those and infection for enteroparasitas. They participated in the study children of both sexes, with age of 3 to 6 years, visitors of the same creche and residents in a neighborhood with precarious hygiene conditions and basic saneamento, in the city of Christmas. The obtained results showed that the faulty environmental and socioeconomic conditions favored to a high infection frequency for enteroparasitas, mainly Trichuris trichiura and Ascaris lumbricoides between the helmintos and Endolimax sleep and Giárdia lamblia among the protozoa. Light malnutrition without deficit protéico was observed in 30% of the children, which didn't also present significant deficiencies of IgA sérica and secretora. The sponged children

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At the cashew nut processing industry it is often the generation of wastewaters containing high content of toxic organic compounds. The presence of these compounds is due mainly to the so called liquid of the cashew nut (CNSL). CNSL, as it is commercially known in Brazil, is the liquid of the cashew nut. It looks like an oil with dark brown color, viscous and presents a high toxicity index due to the chemical composition, i.e. phenol compounds, such as anacardic acid, cardol, 2-methyl cardol and monophenol (cardanol). These compounds are bio resistant to the conventional treatments. Furthermore, the corresponding wastewaters present high content of TOC (total organic carbon). Therefore due to the high degree of toxicity it is very important to study and develop treatments of these wastewaters before discharge to the environmental. This research aims to decompose these compounds using advanced oxidative processes (AOP) based on the photo-Fenton system. The advantage of this system is the fast and non-selective oxidation promoted by the hydroxyl radicals (●OH), that is under determined conditions can totally convert the organic pollutants to CO2 and H2O. In order to evaluate the decomposition of the organic charge system samples of the real wastewater od a processing cashew nut industry were taken. This industry was located at the country of the state of Rio Grande do Norte. The experiments were carried out with a photochemical annular reactor equipped with UV (ultra violet) lamp. Based on preliminary experiments, a Doehlert experimental design was defined to optimize the concentrations of H2O2 and Fe(II) with a total of 13 runs. The experimental conditions were set to pH equal to 3 and temperature of 30°C. The power of the lamps applied was 80W, 125W and 250W. To evaluate the decomposition rate measures of the TOC were accomplished during 4 hours of experiment. According to the results, the organic removal obtained in terms of TOC was 80% minimum and 95% maximum. Furthermore, it was gotten a minimum time of 49 minutes for the removal of 30% of the initial TOC. Based on the obtained experimental results, the photo-Fenton system presents a very satisfactory performance as a complementary treatment of the wastewater studied