179 resultados para Composites. Nickel. Carbides. Granulation. Sintering and plasma
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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This work evaluates fluorinated thin films and their composites for sensor development. Composites were produced using 5 µm starch particles and plasma films obtained from organic fluorinated and silicon compounds reactants. Silicon wafers and aluminum trenches were used as substrates. Film thickness, refractive index and chemical structure were also determined. Scanning electron microscopy shows conformal deposition on aluminum trenches. Films deposited on silicon were exposed to vapor of volatile organic compounds and CV curves were obtained. A qualitative model (FemLab 3.2® program) was proposed for the electronic behavior. These environmentally correct films can be used in electronic devices and preferentially reacted to polar compounds. Nonetheless, due to the difficulty in signal recovery, these films are more effective in one-way sensors, in sub-ppm range.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The human dentition is naturally translucent, opalescent and fluorescent. Differences between the level of fluorescence of tooth structure and restorative materials may result in distinct metameric properties and consequently perceptible disparate esthetic behavior, which impairs the esthetic result of the restorations, frustrating both patients and staff. In this study, we evaluated the level of fluorescence of different composites (Durafill in tones A2 (Du), Charisma in tones A2 (Ch), Venus in tone A2 (Ve), Opallis enamel and dentin in tones A2 (OPD and OPE), Point 4 in tones A2 (P4), Z100 in tones A2 ( Z1), Z250 in tones A2 (Z2), Te-Econom in tones A2 (TE), Tetric Ceram in tones A2 (TC), Tetric Ceram N in tones A1, A2, A4 (TN1, TN2, TN4), Four seasons enamel and dentin in tones A2 (and 4SD 4SE), Empress Direct enamel and dentin in tones A2 (EDE and EDD) and Brilliant in tones A2 (Br)). Cylindrical specimens were prepared, coded and photographed in a standardized manner with a Canon EOS digital camera (400 ISO, 2.8 aperture and 1/ 30 speed), in a dark environment under the action of UV light (25 W). The images were analyzed with the software ScanWhite©-DMC/Darwin systems. The results showed statistical differences between the groups (p < 0.05), and between these same groups and the average fluorescence of the dentition of young (18 to 25 years) and adults (40 to 45 years) taken as control. It can be concluded that: Composites Z100, Z250 (3M ESPE) and Point 4 (Kerr) do not match with the fluorescence of human dentition and the fluorescence of the materials was found to be affected by their own tone.
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Pós-graduação em Ciência dos Materiais - FEIS
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The routine semen evaluation assessing sperm concentration, motility and morphology, does not identify subtle defects in sperm chromatin architecture. Bulls appear to have stable chromatin, with low levels of DNA fragmentation. However, the nature of fragmentation and its impact on fertility remain unclear and there are no detailed reports characterizing the DNA organization and damage in this species. The intensive genetic selection, the use of artificial insemination and in vitro embryo production associated to the cryopreservation process can contribute to the chromatin damage and highlights the importance of sperm DNA integrity for the success of these technologies. Frozen-thawed semen samples from three ejaculates from a Nellore bull showed high levels of morphological sperm abnormalities (55.8±5.1%), and were selected for complementary tests. Damage of acrosomal (76.9±8.9%) and plasma membranes (75.7±9.3%) as well as sperm DNA strand breaks (13.8±9.5%) and protamination deficiency (3.7±0.6%) were significantly higher compared to the values measured in the semen of five Nellore bulls with normospermia (24.3±3.3%; 24.5±6.1%; 0.6±0.5%; 0.4±0.6% for acrosome, plasma membrane, DNA breaks and protamine deficiency, respectively) (P<0.05). Motility and percentage of spermatozoa with low mitochondrial potential showed no differences between groups. This study shows how routine semen analyses (in this case morphology) may point to the length and complexity of sperm cell damage emphasizing the importance of sperm function testing.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Objective The purpose of the present study was to analyze the effects of a 20-week concurrent training (20 WCT) intervention program on gender-specific body composition and metabolic variables in obese adolescents.Subjects and methods Sample was composed of twenty-five obese adolescents, aged between 12 and 15 (13.4 ± 0.96) years. Fat-free mass (FFM), percentage trunk fat mass (TFM%) and percentage fat mass (%FM) were evaluated through dual-energy X-ray absorptiometry (DXA). Measurement of intra-abdominal adiposity (IAAT) was performed using ultrasound. Blood pressure was measured and blood samples analyzed for total cholesterol (TC), high-density lipoprotein cholesterol (HDL-c), low-density lipoprotein cholesterol (LDL-c), triglycerides (TG) and plasma glucose. All participants performed the concurrent training (combination of weight training and aerobic training) three times per week, one hour per day, for 20 weeks. Descriptive analysis and analysis of variance (ANOVA) for repeated measures were used to compare baseline, 10 week and 20 week moments using the Bonferroni post-hoc test. Statistical significance was set at p < 0.05. Significant decrease in TC, LDL-c and TFM% were verified in both genders after the 10 initial weeks of concurrent training.Results A significant increase in height was found in both the male and female groups (p = 0.001 and p = 0.047, respectively), after 20 weeks of concurrent training. In addition, several modifications were observed in body composition and metabolic variables, with a significant decrease in BMI (p = 0.002 and p = 0.017), BMI z-score (p = 0.033 and p = 0.004), FM% (p = 0.002 and p = 0.002), TFM% (p = 0.009 and p = 0.018), TC (p = 0.042 and p = 0.001) and LDL-c (p = 0.006 and p = 0.001) in the male and female groups, respectively, after 20 weeks of intervention when compared with baseline.Conclusion Our results identified that concurrent training was an effective intervention for treating metabolic variable and body composition disorders, in both genders, by decreasing adiposity with consequent improvement in BMI and BMI z-scores, and enhancement in lipid profile variables.
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The neural circuitry for social behavior and aggression appears to be evolutionarily conserved across the vertebrate subphylum and involves a complex neural network that includes the hypothalamus as a key structure. In the present study, we evaluated the changes in monoamine levels in the hypothalamus and on serum cortisol and plasma glucose of resident matrinxã (Brycon amazonicus) submitted to a social challenge (introduction of an intruder in their territory). The fight promoted a significant increase in hypothalamic 5-HT, NA and DA levels and on the metabolites 5-HIAA and DOPAC, and decreased 5-HIAA/5-HT and DOPAC/DA ratios in resident fish. Furthermore, an increase in serum cortisol and plasma glucose was also observed after the fight. Resident fish presented a high aggressiveness even with increased 5-HT levels in the hypothalamus. The alteration in hypothalamic monoaminergic activity of matrinxã suggests that this diencephalic region is involved in aggression and stress modulation in fish; however, it does not exclude the participation of other brain areas not tested here.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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The development of a reliable technique to freeze epididymal semen would provide a unique opportunity to preserve valuable genetic material from unexpectedly lost stallions. The aim of this study was to compare the apoptotic indices of sperm obtained from ejaculate, sperm recently recovered from the epididymides (EP), and sperm recovered from epididymides stored at 5 C for 24 hours (EP-stored). For the first category, two ejaculates from seven stallions were collected and then submitted to cryopreservation using an egg yolk-based extender. One week after the last semen collection, the stallions were submitted to bilateral orchiectomy, and sperm from one of the cauda epididymis was harvested immediately after castration (EP). The remaining testicle was stored in a passive refrigeration container at 5 C for 24 hours before the cauda epididymal sperm was harvested (EP-stored). Sperm harvesting from the epididymis for EP and EP-stored was performed by retrograde flushing of the caudal portion of the epididymis using a skim milk-based extender. The recovered sperm was then cryopreserved using the egg yolk-based extender. Sperm motility parameters were studied by computerassisted semen analysis, and apoptosis was estimated by measuring caspase activity and membrane phospholipid translocation using epifluorescence microscopy. The samples were evaluated immediately (0 hour) and 8 hours after thawing. At 0 hour, no differences in sperm parameters were observed among the groups, but after 8 hours, significant statistical differences were observed in sperm motility parameters and plasma membrane integrity among the treatment groups. In addition, viable cells with no apoptotic signs were more prevalent in EP and EP-stored, suggesting that epididymal sperm is less sensitive to the cold shock caused by sperm cryopreservation.