951 resultados para cylindrical grinding


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This is a case report of enteric protothecosis caused by Prototheca zopfii in an eight-year-old male mixed breed dog with a history of chronic bloody diarrhea, loss of appetite and weight loss. Algae were isolated from rectal scrapings in defibrinated sheep blood agar and dextrose Sabouraud agar. Cytological evaluation showed the presence of globular and cylindrical organisms with a defined capsule and variable number of endospores, characteristic of the genus Prototheca, in the rectum of the animal. Scanning electron microscopy of P. zopfii strains at different development stages confirmed the diagnosis of algal infection. Molecular identification using a conserved 18S rDNA gene sequence determined that the strain belonged to genotype 2. This report describes success on treatment of canine protothecosis, diagnosed based on clinical, cytological, microbiological, scanning electron microscopy and genotypical findings. (c) 2009 Elsevier Ltd. All rights reserved.

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OBJETIVO: avaliar a freqüência dos sinais e sintomas, dos hábitos parafuncionais e das características oclusais de 80 crianças, pacientes da clínica de Ortodontia Preventiva da Faculdade de Odontologia de Araçatuba - UNESP. METODOLOGIA: o exame clínico constituiu-se de avaliação das características oclusais do paciente e observação da presença de hábitos parafuncionais. As crianças foram submetidas a uma entrevista, supervisionadas pelos pais, cujas perguntas relacionavam-se com os sinais e sintomas da disfunção. RESULTADOS E CONCLUSÕES: concluiu-se que os sinais e sintomas mais freqüentes foram o hábito de ranger os dentes, dores de cabeça e ruídos na ATM. A onicofagia e o bruxismo foram os hábitos parafuncionais mais prevalentes. A freqüência de sinais e sintomas da disfunção temporomandibular pode ser verificada em crianças por meio da entrevista e exame clínico minucioso.

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OBJETIVO: Apresentar uma revisão de literatura sobre o bruxismo na infância, abordando os fatores etiológicos, as características clínicas, os sinais e sintomas, a importância do diagnóstico por parte dos pediatras e odontopediatras e o tratamento multidisciplinar desta condição parafuncional. FONTES DE DADOS: Foram selecionados os artigos mais relevantes sobre o tema publicados desde 1907 até 2007, com pesquisa realizada no Medline, na Bibliografia Brasileira de Odontologia (BBO) e em livros de Odontologia. SÍNTESE DOS DADOS: O bruxismo é definido como um hábito não funcional do sistema mastigatório, caracterizado pelo ato de ranger ou apertar os dentes, podendo ocorrer durante o dia e durante o sono. A etiologia é multifatorial e a literatura sugere vários fatores associados: dentário, fisiológico, psicológico e neurológico. As forças exercidas pelo bruxismo podem provocar distúrbios em diferentes graus nos dentes e nos tecidos de suporte, na musculatura e na articulação têmporo-mandibular. O sinal mais comum é o desgaste nas faces incisais dos dentes anteriores e oclusais nos posteriores, além de mobilidade e hipersensibilidade dentárias, fratura de cúspides e restaurações e hipertonicidade dos músculos mastigatórios. CONCLUSÃO: O conhecimento dos fatores etiológicos e das características clínicas do bruxismo na infância é fundamental para que o diagnóstico seja precoce, permitindo que pediatras, odontopediatras e psicólogos possam estabelecer um tratamento multidisciplinar e favoreçam o desenvolvimento integral da criança para a promoção de saúde e bem-estar individual.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Innocuous biocompatible materials have been searched to repair or reconstruct bone defects. Their goal is to restore the function of live or dead tissues. This study compared connective tissue and bone reaction when exposed to demineralized bovine bone matrix and a polyurethane resin derived from castor bean (Ricinus communis). Forty-five rats were assigned to 3 groups of 15 animals (control, bovine bone and polyurethane). A cylindrical defect was created on mandible base and filled with bovine bone matrix and the polyurethane. Control group received no treatment. Analyses were performed after 15, 45 and 60 days (5 animals each). Histological analysis revealed connective tissue tolerance to bovine bone with local inflammatory response similar to that of the control group. After 15 days, all groups demonstrated similar outcomes, with mild inflammatory reaction, probably due to the surgical procedure rather than to the material. In the polymer group, after 60 days, scarce multinucleated cells could still be observed. In general, all groups showed good stability and osteogenic connective tissue with blood vessels into the surgical area. The results suggest biocompatibility of both materials, seen by their integration into rat mandible. Moreover, the polyurethane seems to be an alternative in bone reconstruction and it is an inexhaustible source of biomaterial.

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Statement of problem. When clinical fractures of the ceramic veneer on metal-ceramic prostheses can be repaired, the need for remake may be eliminated or postponed. Many different ceramic repair materials are available, and bond strength data are necessary for predicting the success of a given repair system.Purpose. This study evaluated the shear bond strength of different repair systems for metal-ceramic restorations applied on metal and porcelain.Material and methods. Fifty cylindrical specimens (9 X 3 mm) were fabricated in a nickel-chromium alloy (Vera Bond 11) and 50 in feldspathic porcelain (Noritakc). Metal (M) and porcelain (P) specimens were embedded in a polyvinyl chloride (PVC) ring and received I of the following bonding and resin composite repair systems (n=10): Clearfil SE Bond/Clearfil AP-X (CL), Bistite II DC/Palfique (BT), Cojet Sand/Z100 (Q), Scotchbond Multipurpose Plus/Z100 (SB) (control group), or Cojet Sand plus Scotchbond Multipurpose Plus/Z100 (CJSB). The specimens were stored in distilled water for 24 hours at 37 degrees C, thermal cycled (1000 cycles at 5 degrees C to 55 degrees C), and stored at 37 degrees C for 8 days. Shear bond tests between the metal or ceramic specimens and repair systems were performed in a mechanical testing machine with a crosshead speed of 0.5 mm/min. Mean shear bond strength values (MPa) were submitted to 1-way ANOVA and Tukey honestly significant difference tests (alpha=.05). Each specimen was examined under a stereoscopic lens with X 30 magnification, and mode of failure was classified as adhesive, cohesive, or a combination.Results. on metal, the mean shear bond strength values for the groups were as follows: MCL, 18.40 +/- 2.88(b); MBT, 8.57 +/- 1.00(d); MCJ, 25.24 +/- 3.46(a); MSB, 16.26 +/- 3.09(bc); and MCJSB, 13.11 +/- 1.24(c). on porcelain, the mean shear bond strength values ofeach group were as follows: PCL, 16.91 +/- 2.22(b); PBT, 18.04 +/- 3.2(ab); PCJ, 19.54 +/- 3.77(ab); PSB, 21.05 +/- 3.22(a); and PCJSB, 16.18 +/- 1.71(b). Within each substrate, identical superscript letters denote no significant differences among groups.Conclusions. The bond strength for the metal substrate was significantly higher using the Q system. For porcelain, SB, Q, and BT systems showed the highest shear bond strength values, and only SB was significantly different compared to CL and CJSB (P <.05).

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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This study compared the tensile strength and fracture mechanism of tungsten inert gas (TIG) welds in cylindrical rods of commercially pure titanium (cp Ti) with those of laser welds and intact samples. Thirty dumbbell-shaped samples were developed by using brass rods as patterns. The samples were invested in casings, subjected to thermal cycles, and positioned in a plasma arc welding machine under argon atmosphere and vacuum, and titanium was injected under vacuum/pressure. The samples were X-rayed to detect possible welding flaws and randomly assigned to three groups to test the tensile strength and the fracture mechanism: intact, laser welding, and TIG welding. The tensile test results were investigated using ANOVA, which indicated that the samples were statistically similar. The fracture analysis showed that the cpTi samples subjected to laser welding exhibited brittle fracture and those subjected to TIG welding exhibited mixed brittle/ductile fracture with a predominance of ductile fracture with the presence of microcavities and cleavage areas. Intact samples presented the characteristic straightening in the fracture areas, indicating the ductility of the material.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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We studied the colour preference of isolated Nile tilapia (Oreochromis niloticus) and whether previous residence or body size can affect environmental colour choice. In the first phase, a cylindrical tank was divided into five differently coloured compartments (yellow, blue, green, white and red), a single fish was introduced into the tank and the frequency at which this fish visited each compartment was recorded over a 2-day study period. An increasingly larger fish (approx +2 cm in length each time) was then added into the tank on each of days 3, 5 and 7 (=four fish in the tank by day 7), and the frequency at which each fish visited the different compartments of the tank was observed twice a day to obtain visit frequency data on the differently sized fishes. This experiment was replicated six times. In the first phase, the solitary fish established residence inside the yellow compartment on the first and second days. Following the introduction of a larger fish, the smaller fish was displaced from the occupied compartment. Nile tilapia possibly shows this preference for yellow as a function of its visual spectral sensitivity and/or the spectral characteristics of its natural environment. Moreover, body size is an important factor in determining hierarchical dominance and territorial defence, and dominant fish chose the preferred environmental colour compartment as their territory.

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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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Aim: Studies on feeding of early life stages are very important to the understanding of the biology and trophic ecology of fish species. Therefore, the aim of this work is to describe the development of the digestive tube, and to characterize the diet of larvae and juveniles of Bryconamericus stramineus Eigenmann, 1908 of the upper Parana River floodplain; Methods: Larvae were obtained from, monthly samples during nychthemeral cycles with four-hour interval between samplings from February/91 to February/92, utilizing a conical-cylindrical plankton net; Results: At the preflexion stage, larvae at approximately 4.00 mm SL, showed a morphologically undifferentiated straight tube, with the anterior region more dilated. At the flexion stage a differentiation in the anterior region of the digestive tube occurs, with the intestine wall getting thicker (8.30 mm SL). The formation of pyloric caeca occurs at 9.00 mm SL. At the postflexion stage the first loop is formed at 9.25 mm SL and the second loop at about 10.00 mm SL. Bryconamericus stramineus consumed mainly cladocerans, also ingesting copepods, rotifers, nematodes, algae, insects and inorganic particles. Along the development, there was an increase in the number of food items and a diversification in the number of consumed taxa; Conclusions: Changes in the diet of B. stramineus larvae were not observed, being them zooplanktivores during all the initial development. However, an increase of large preys, such as insects larvae, was observed at the end of the larval period and in juveniles, suggesting a tendency towards invertivory. Larvae and juveniles preferentially fed during the night.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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O presente trabalho teve por objetivo o estudo morfoanatômico dos órgãos vegetativos de Piper hispidum, visando a estabelecer características marcantes para a sua identificação e auxiliar estudos taxonômicos e farmacobotânicos. O material vegetal fresco e fixado foi estudado segundo as técnicas usuais de corte e coloração, incluindo análise em MEV. Piper hispidum é um arbusto com caule cilíndrico, nodoso, verde claro, com folhas alternas, ovadas, de cor verde-escura na face adaxial e verde claro na abaxial. Dentre as características anatômicas importantes para sua identificação destacam-se: parênquima cortical da raiz apresentando grupos de esclereídes. Córtex caulinar com faixas descontínuas de colênquima do tipo angular e tecido vascular organizado em dois círculos descontínuos de feixes colaterais. A folha é dorsiventral, hipoestomática, com estômatos tetracíticos. Hipoderme adaxial descontínua e abaxial frouxa com número variável de camadas; tricomas tectores e glandulares ocorrem nas duas faces. Epiderme uniestratificada e idioblastos oleíferos ocorrem em todos os órgãos.