401 resultados para Temperature. eng
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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This study describes the influence of incubation temperature during initial development phase on the morphology and muscle growth characteristics in the pacu (Piaractus mesopotamicus). Pacu eggs were incubated at 25, 27, and 29 degreesC until hatching. After day 5, fish from each temperature were transferred to 5001 tanks. At hatching and after 5, 25, and 60 days, muscle samples were collected, some were frozen in liquid nitrogen and others fixed in 4% paraformaldehyde or 2.5% glutaraldehyde. These samples were used for morphological, histochemical, immunohistochemical, and morphometric analysis. At hatching, we observed a superficial monolayer of small diameter fibers, lying just beneath the skin surrounding several round cells. From day 5, we observed two distinct populations of muscle fibers distributed in two layers: (1) red-in a superficial region with aerobic activity, and following acid preincubation, high mATPase activity, and 2) white-with anaerobic activity, and following alkaline preincubation, high mATPase activity. Twenty-five days after hatching, an intermediate layer and cell proliferating zones could be seen in the dorsal fin muscle region, with intermediate characteristics. Throughout the experimental period, there was an increase in muscle mass due to new fiber recruitment in the cell proliferating zones and between the more differentiated fibers in red, intermediate, and white muscles. This was more obvious from day 25, and at 29 degreesC than at 25 and 27 degreesC. Fiber hypertrophy occurred from hatching to 60 days and was more evident from 5 to 25 days. The number of proliferating nuclei (PCNA-labelling) increased from hatching to 60 days, and was more obvious in the 29 degreesC group at 60 days. Our results show that at incubation temperatures of 25, 27 and 29 degreesC, hypertrophy was predominantly from hatching to 25 days, after that muscle growth by hyperplastic mechanism increased. The interaction of muscle hypertrophic and hyperplastic growth processes in the 29 degreesC group produced the largest fish at the end of the experiment. (C) 2004 Elsevier B.V. All rights reserved.
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The objective of this study was to evaluate the associations among milk production, rectal temperature, and pregnancy maintenance in lactating recipient dairy cows. Data were collected during an 11-mo period from 463 Holstein cows (203 primiparous and 260 multiparous) assigned to a fixed-time embryo transfer (ET) protocol. Only cows detected with a visible corpus luteum immediately prior to ET were used. Rectal temperatures were collected from all cows on the same day of ET. Milk production at ET was calculated by averaging individual daily milk production during the 7 d preceding ET. Pregnancy diagnosis was performed by transrectal ultrasonography 21 d after ET. Cows were ranked and assigned to groups according to median milk production (median = 35 kg/d; HPROD = above median; LPROD = below median) and rectal temperature (<= 39.0 degrees C = LTEMP; >39.0 degrees C = HTEMP). A milk production x temperature group interaction was detected (P = 0.04) for pregnancy analysis because HTEMP cows ranked as LPROD were 3.1 time more likely to maintain pregnancy compared with HTEMP cows ranked as HPROD (P = 0.03). Milk production did not affect (P = 0.55) odds of pregnancy maintenance within LTEMP cows, however, and no differences in odds of pregnancy maintenance were detected between HTEMP and LTEMP within milk production groups (P > 0.11). Within HTEMP cows, increased milk production decreased the probability of pregnancy maintenance linearly, whereas within LTEMP cows, increased milk production increased the probability of pregnancy maintenance linearly. Within HPROD, increased rectal temperature decreased the probability of pregnancy maintenance linearly, whereas within LPROD cows, no associations between rectal temperatures and probability of cows to maintain pregnancy were detected. In summary, high-producing dairy cows with rectal temperatures below 39.0 degrees C did not experience reduced pregnancy maintenance to ET compared to cohorts with reduced milk production. (C) 2011 Elsevier B.V. All rights reserved.
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This study evaluated the microtensile bond strength test (mu T), micromorphology of resin-enamel interface (RET) and etching patterns (EP) promoted by the etch-and-rinse adhesive, Prime&Bond NT (PB), and two self-etching adhesives, Clearfil SE Bond (SE) and Adper Prompt L-Pop (APR), to ground bovine enamel surfaces' when applied at temperatures of 5 degrees C (C), 40 degrees C (H) and 20 degrees C (R). Materials and Methods. Sixty-three bovine incisors were randomly divided into nine experimental groups (n=7) according to adhesive systems and temperatures. The buccal enamel surfaces were flattened with 600-grit SiC paper and abraded with a diamond bur under water-cooling. The adhesive systems were applied according to the manufacturer's instructions. After the restorative procedures, the specimens were sectioned into five slabs. Four slabs were prepared for mu T and one for interface analysis. For etching pattern analysis, the remaining 16 bovine enamel fragments were used (n=2). The adhesives were applied and the surfaces were rinsed with organic solvents after application. The specimens for RET and EP analysis were prepared for SEM analysis. Results. No significant differences among the adhesives were found at R temperature. However, at 5 degrees C, PB and APR presented lower bond strength than SE. At H temperature, higher bond strength was observed for PB than for APR and SE. At C and H temperature, formation of the interdiffusion zone was impaired and the treated enamel surfaces presented an undefined EP.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Glass transition temperature of hard chairside reline materials after post-polymerisation treatments
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Tanomaru-Filho M, Silveira GF, Reis JMSN, Bonetti-Filho I, Guerreiro-Tanomaru JM. Effect of compression load and temperature on thermomechanical tests for gutta-percha and Resilon (R). International Endodontic Journal, 44, 1019-1023, 2011.Aim To analyse a method used to evaluate the thermomechanical properties of gutta-percha and Resilon at different temperatures and compression loads.Methodology Two hundred and seventy specimens measuring 10 mm in diameter and 1.5 mm in height were made from the following materials: conventional gutta-percha (GCO). thermoplastic gutta-percha (GTP) and Resilon (R) cones (RE). After 24 h, the specimens were placed in water at 50 degrees C. 60 degrees C or 70 degrees C for 60 s. After that, specimens were placed between two glass slabs, and loads weighing 1.0, 3.0 or 5.0 kg were applied. Images of the specimens were digitized before and after the test and analysed using imaging software to determine their initial and final areas. The thermomechanical property of each material was determined by the difference between the initial and final areas of the specimens. Data were subjected to ANOVA and SNK tests at 5% significance. To verify a possible correlation between the results of the materials, linear regression coefficients (r) were calculated.Results Data showed higher flow area values for RE under all compression loads at 70 degrees C and under the 5.0 kg load at 60 degrees C (P < 0.05). Regarding gutta-percha, GTP showed higher flow under loads weighing 3.0 and 5.0 kg. at 60 and 70 degrees C (P < 0.05). GCO presented higher flow at 70 degrees C with a load of 5.0 kg. Regression analyses showed a poor linear correlation amongst the results of the materials under the different experimental conditions.Conclusion Gutta-percha and Resilon (R) cones require different compression loads and temperatures for evaluation of their thermomechanical properties. For all materials, the greatest flow occurred at 70 degrees C under a load of 5.0 kg: therefore. these parameters may be adopted when evaluating endodontic tilling materials.
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Aim To analyse the thermoplasticity of several endodontic filling materials using the Obtura II System at different temperature settings.Methodology The following materials based on gutta-percha: Regular Obtura (OBT), Obtura Flow 150 (OBT F), Endo Flow (EDF), Odous (ODO) and the synthetic thermoplastic polymer material Resilon (RE) were heated using the Obtura II System at three temperature settings (140, 170 and 200 degrees C). Samples of the heated materials were placed on the sensor of a digital thermometer (THR-140; Instrutherm, São Paulo, Brazil) to determine their real temperature (RT) when the system was set at 140 degrees C (from 64.5 to 69 degrees C), 170 degrees C (from 73.8 to 77.5 degrees C) and 200 degrees C (from 83.6 degrees C for EDF and 100 degrees C for RE). Specimens (n = 30) were made by placing samples of each material in metallic ring moulds and compressing them between two glass slabs. After 24 h, specimens (n = 10) were heated at the different settings (RT) and submitted to compression under a 5-kg load. Plasticization was assessed by calculating the differences between the post-compression and initial diameters of each specimen. Data were submitted to ANOVA and Tukey's test at 5% significance.Results At 140 degrees C, Obtura Flow presented the highest thermoplasticity values and Regular Obtura, the lowest. At 170 degrees C, Obtura Flow and Resilon demonstrated greater plasticization. Resilon had the highest mean thermoplasticity values at 200 degrees C.Conclusions Thermoplasticity values were influenced both by the temperature settings on the Obtura II System and by the type of material analysed. Obtura Flow and Resilon had the highest mean thermoplasticity values.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The purpose of the present work was to study various aspects of the germination of seeds of Senna occidentalis Link, which had presented promising results in biological activity against the etiological agent of malaria. These aspects were dormancy, temperatures of germination and photoblastic response. In the dormancy studies, the treatments used were: unscarified seed (control); tegument puncture with sharp point; and scarification with sand-paper and immersion in concentrated sulfuric acid during 5, 10, 15 and 20 minutes. For the study of temperature and photoblast, the seeds were immersed in sulfuric acid for 20 minutes, submitted to temperatures of 10 to 45degreesC, at intervals of 5degreesC, both under light and in the dark. The seeds presented dormancy related to tegument, the best treatments for breaking dormancy were immersion in sulfuric acid for 15 and 20 minutes. At temperatures 25 and 30degreesC, the best results of percentage and index of velocity of germination were observed, at which the seeds behaved as neutral photoblastic; there was no germination at 10 or at 45degreesC.
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The aim was to study the effect of different storage temperatures on quality of red mombin fruit. The red mombin fruits were obtained from the Company CEAGESP/São Paulo/Brazil and transported in cool boxes to the laboratory, where they were selected on the base of appearance, maturity lack of physical damage, sanitized in 50 ppm chlorine-free solution and packaged in polystyrene trays wrapped with film of polyvinyl chloride (PVC). The experiment was a completely randomized design with three temperatures (4, 8 and 25 degrees C) and 5 time intervals (0, 2, 4, 6 and 8 days after the experiment installation). In each survey firmness, titratable acidity, soluble solids, ascorbic acid content, the skin color and also the release of CO(2) by the fruit over time were evaluated. It was observed that low temperatures prolong the fruits shelf life and the storage temperature influences the characteristics, the temperature of 8 degrees C was most suitable for the storage of red mombin fruits. Besides, the fruit color was a good indicator of changes in the pulp during storage.
Larval density, temperature and biological aspects of Chrysomya megacephala (Diptera: Calliphoridae)
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Analisou-se o efeito de duas densidades larvais e duas temperaturas sobre a sobrevivência, fecundidade e tamanho corpóreo de C. megacephala em condições experimentais. Nenhum efeito simultâneo da densidade e temperatura foi encontrado sobre as variáveis investigadas em C. megacephala. Entretanto, foram observados efeitos isolados significativos da densidade e da temperatura sobre a fecundidade e tamanho corpóreo. A importância desses resultados para a dinâmica populacional de C. megacephala foi discutida.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)