989 resultados para estrutura de superfície
Resumo:
This experiment was performed aiming to evaluate tiller population density, forage mass and its morphological components on pastures of Brachiaria decumbens cv. Basilisk. during deferment. The treatments encompassed four deferred grazing periods (18, 46, 74 and 121 days). A randomized block design with two replications was used. The numbers of vegetative tillers (VT), reproductive tillers (RT) and dead tillers (DT) in the pasture were determined. The masses of green leaf blade (GLBM), dead stem (DSM) and dead forage (DFM) were also determined. There was a reduction in the number of VT (from 1, 491 to 944 tiller m-2) during the deferment period. RT and DT numbers were not influenced by the deferment periods. Their averages were 211 and 456 tiller m-2, respectively. Longer deferring periods resulted in an increase in GSM (from 2, 965 to 4, 877 kg ha-1 of dry mass) and DFM (from 2, 324 to 4, 823 kg ha-1 of dry mass), but it did not influence GLBM (average of 2, 047 kg ha-1 of dry mass). In Viçosa, Minas Gerais State Brazil, Brachiaria decumbens cv. Basilisk pasture fertilized and deferred in the beginning of March must be kept deferred for about 70 days in order to conciliate both quality and quantity forage production.
Resumo:
Objective: To evaluate the influence of different air abrasion protocols on the surface roughness of an yttria-stabilized polycrystalline tetragonal zirconia) (Y-TZP) ceramic, as well as the surface topography of the ceramic after the treatment. Method: Fifty-four specimens (7.5×4×7.5mm) obtained from two ceramic blocks (LAVA, 3M ESPE) were flattened with fine-grit sandpaper and subjected to sintering in the ceramic system's specific firing oven. Next, the specimens were embedded in acrylic resin and the surfaces to be treated were polished in a polishing machine using sandpapers of decreasing abrasion (600- to 1,200-grit) followed by felt discs with 10μm and 3μm polishing pastes and colloidal silica. The specimens were then randomly assigned to 9 groups, according to factors particle and pressure(n=6): Gr1- control; Gr2- Al 2O 3(50μm)/2.5 bar; Gr3- Al 2O 3(110μm)/2.5 bar; Gr4- SiO 2(30μm)/2.5 bar; Gr5- SiO 2(30μm)/2.5 bar; Gr6- Al 2O 3(50μm)/3.5 bar; Gr7- Al2O3(110μm)/3.5 bar; Gr8- SiO 2(30μm)/3.5 bar; Gr9- SiO 2(30μm)/3.5 bar. After treatments, surface roughness was analyzed by a digital optical profilometer and the morphology was examined by scanning electron microscopy (SEM). Data (μm) were subjected to statistical analysis by Dunnett's test (5%), two-way ANOVA and Tukey's test (5%). Results: The type of particle (p=0.0001) and the pressure (p=0.0001) used in the air abrasion protocols influenced the surface roughness values among the experimental groups (ANOVA). The mean surface roughness values (μm) obtained for the experimental groups (Gr2 to Gr9) were, respectively: 0.37 D; 0.56 BC; 0.46 BC; 0.48 CD; 0.59 BC; 0.82 A; 0.53B CD; 0.67 AB. The SEM analysis revealed that Al 2O 3, regardless of the particle size and pressure used, caused damage to the surface of the specimens, as it produced superficial damages on the ceramic, in the form of grooves and cracks. Conclusion: Al2O3 (110 μm/3.5 bar) air abrasion promoted the highest surface roughness on the ceramics, but it does not mean that this protocol promotes better ceramic-cement union compared to the other air abrasion protocols.
Resumo:
Two experiments (experiment 1 - conventional feeding and experiment 2 - feeding of the sows, starting at 109 days of pregnancy and during lactation, and the lactating piglets, with rations without soybean meal) were conducted to evaluate the effects of sources of protein (soybean meal-SBM, extruded semi-integral soybean-ESISB, and milk products-MP) on the intestinal morphology of piglets slaughtered at the 0, 5 and 15 days later at weaning. Twenty-seven piglets weaned with 25 days of age were used, being nine piglets slaughter in each slaughtering age. A 3 ×3 factorial (3 diets × 3 slaughtering ages) was studied, according to a randomized block design. The results showed that animals receiving SBM, presented lower values of villi height and villus: crypt ratio when compared to those that received ESISB or MP. The villi height and the villus: crypt ratio were not affected by the differential feeding of the sows and of the piglets before the weaning. The depth of the crypt was not affected by diets or slaughtering ages in none of the segments studied being, however, smaller in the duodenum and bigger in the jejunum and ileo of the animals of exp. 2. It was concluded that the SBM was the affected the height of the villi and the relationship villi: Crypt negatively after it weans. The intestinal morphology was more affected at five days, showing signals of recovering at 15 days after weaning and that the feeding of the sows did not affect the morphology of the segments of the thin intestine.
Resumo:
The knowledge of interaction between infective larvae setting and the type of grass is important to epidemiological studies and the control of gastrointestinal nematodes in sheep. The objective of this work was to evaluate the effects of three species of forage grasses on pasture characteristics and the vertical distribution of infective larvae (L3) of gastrointestinal nematodes of woolless sheep on the grasses during the rainy season. Sixty non-periparturients ewes were used, naturally infected, equally distributed on 2ha paddocks sowed with Tanzania, star, and gamba grasses, managed under continuous grazing system, from October 2003 to March 2004, at Santa Bárbara farm, Barreiras-Bahia-Brazil. Data of three samples between December 2003 and March 2004 were analyzed by SAS, using split-plot design, with 10 replications. Infective larvae of Haemonchus spp. and Trichostrongylus spp. were observed on forage in all stratus of vertical layer of the grasses without a defined pattern. Pastures with different characteristics under continuous grazing system had good conditions for developing infective larvae of sheep.
Resumo:
In the majority of cases of bone fracture requiring surgery, orthopedic implants (screw-plate and screw) are used for osteosynthesis and the infections associated with such implants are due to the growth of microorganisms in biofilms. The objective of this study was to identify microorganisms recovered from osteosynthesis implants used to fix bone fractures, to assess the viability of the cells and the ability of staphylococci to adhere to a substrate and to determine their sensitivity/resistance to antimicrobials. After surgical removal, the metal parts of austenitic stainless steel (ASTM F138/F139 or ISO NBR 5832-1/9) were transported to the Laboratory of Clinical Microbiology, washed in buffer and subjected to ultrasonic bath at 40±2 kHz for 5 minutes. The sonicated fluid was used to seed solid culture media and cell viability was assessed under the microscope by with the aid of a fluorescent marker. The production of extracellular polysaccharide by Staphylococcus spp. was investigated by means of adhesion to a polystyrene plate. The profile of susceptibility to antimicrobials was determined by the disk diffusion assay. The most frequently isolated bacteria included coagulase-negative Staphylococcus resistant to erythromycin, clindamycin and oxacillin. Less frequent were Pseudomonas aeruginosa resistant to trimethoprim/sulfamethoxazole and ampicillin, Acinetobacter baumannii resistant to ceftazidime, Enterobacter cloacae resistant to cephalothin, cefoxitin, cefazolin, levofloxacin and ciprofloxacin, Bacillus spp. and Candida tropicalis. The observation of slides by fluorescence microscope showed clusters of living cells embedded in a transparent matrix. The test for adherence of coagulase-negative Staphylococcus to a polystyrene plate showed that these microorganisms produce extracellular polysaccharide. In conclusion, the metal parts were colonized by bacteria related to orthopedic implant infection, which were resistant to multiple antibiotics.
Resumo:
The paca (Cuniculus paca) is the second largest rodent of the Brazilian fauna. The excellent meat quality of this specie encourages the development of their commercial production. Moreover, this animal can become a viable alternative for animal experimentation although there exists scarce detailed information concerning their morphology. Therefore the purpose of this study is to describe the morphology, morphometry and ultrastructure in segments of the cranial and caudal portions of vena cava in four adult males and females of Cuniculus paca from the squad of Wild Animals Sector of Animal Science Department of FCAV-Unesp. Parts of the segments were examined by light microscopy and part by scanning electron microscopy. Thickness measures of the tunica intima and media complex and tunica adventitia of the vena cava were taken and analyzed using T test (p<0.05). In vena cava the thickness values of the intima, media and adventitia, for all animals, were significantly higher in the cranial segment. The layers of the vessel walls showed variations in structure and thickness, presumably due to an adaptation to functional demand.
Resumo:
The turtle Trachemys scripta elegans popularly known as American tiger water are native regions winged Florida and Mississippi, in the United States. We used twenty (20) turtles (Trachemys scripta elegans), adult males and females, which were euthanized under Resolution 714 of June 20, 2002 the Federal Council of Veterinary Medicine (CFMV). After euthanasia were identified aortas right and left to the injection of Neoprene latex 450, stained with specific pigment. To obtain the vinyl mold aorta was injected through the right and left vinyl acetate, followed by corrosion in sulfuric acid. It was observed that the pancreas is closely related to the liver, gizzard, gall bladder, and duodenum. His face cranial this distal region of the pylorus, while its caudal along the cranial region of the duodenum. Anatomically, the pancreas is an elongated body structure featuring a lightly lobed. As to the pancreas arterial vasculature is flushed in its transverse plane of two arteries arising from the celiac artery, and each antimere two pancreaticoduodenal artery in the cranial region, close to the pylorus by the pancreaticoduodenal artery flow in the caudal portion along the duodenum.
Resumo:
Objective: To evaluate fluoride ion release from two anhydrous glass ionomer cements (GICs) and two resin-modified GICs (RMGICs) before and after recharge with 2% neutral sodium fluoride for 4 min and after surface protection of the Maxxion R GIC with an adhesive system, a cavity varnish and a colorless nail polish. Method: A stainless steel 2x6 mm matrix was used for fabricating 5 specimens of each material, which were immersed in 5 mL of deionized water, renewed every 24 h. Measurements with a potentiometer were performed on days 1, 2, 9 and 17, in the 1st and 2nd phases, and the specimens were buffered with a TISAB III solution. In the 2nd phase, the specimens were subjected to recharge and immersed again in 5 mL of deionized water. In the 3rd phase, the GIC surfaces were protected and readings were made at 5 min, 24 h, 48 h and 72 h. Tukey's post-hoc and Student's t tests were used for statistical analyses (p<0.05). Results: There was statistically significant difference in the comparison between the 1st and 2nd phases for all materials, except at day 2 for Vidrion R and VitroFil LC. In the 3rd phase, it was observed that for all materials, comparison of the first 5 min with the other times revealed statistically significant differences among the means of fluoride ion release. In the comparison with the other times, both the varnish and the colorless nail polish presented statistically significant difference between 24 and 48 h as well as between 24 and 72 h. Conclusion: The anhydrous GICs were more effective in fluoride ion release and recharge compared with the RMGICs. Maxxion R presented a homogeneous and statistically significant behavior in both phases. All materials for surface protection were efficient and the colorless nail polish had the best behavior.
Resumo:
In this work, surface modification of the Ti-6Al-4V alloy by irradiation with a Nd:YAG laser beam was studied. The matrix spacing was varied and the other parameters were kept constant. After theirradiation, the samples were immersed into SBF solution (Simulated Body Fluid) for 7 days at 37 ° C for nucleation and formation of calcium phosphates. After this period, the samples were subjected to a heat treatment at 600 °C. X-ray diffraction results indicated the formation of a mixture of phases containing hydroxyapatite and tricalcium phosphate. Infrared analysis demonstrated the presence of bands related to hydroxyapatite. SEM micrographs showed that different matrix spacing used leads to the formation of different morphologies.The 0.01 cm spacing induced the formation of microspheres, characteristic of the hydroxyapatite phase, while for 0.02 cm spacing, only a non-homogeneous coating was obtained. Therefore, the use of laser in the production of active surfaces for deposition of bioceramics proved to be viable, and the final coating has potential for applications in the field of dental implants.
Resumo:
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Resumo:
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Resumo:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Resumo:
Pós-graduação em Engenharia Elétrica - FEIS
Resumo:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Resumo:
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)