960 resultados para Leakage.


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

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

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Objective: This study was intended to quantify the marginal leakage of three glass-ionomer-resin composite hybrid materials and compare it with the leakage exhibited by a glass-ionomer cement and a bonded resin composite system. Method and materials: Standardized Class V cavities were prepared on root surfaces of 105 extracted human teeth, randomly assigned to five groups of 21 each, and restored with either Ketac-Fil Aplicap, Z100/Scotchbond Multi-Purpose Plus, Vitremer, Photac-Fil Aplicap, or Dyract. The teeth were thermally stressed for 500 cycles and stained with methylene blue. The microleakage was quantified spectrophotometrically, and the data were statistically analyzed with Friedman's test. Results: There were no significant differences in microleakage among the five groups. Restorations of all tested materials showed some marginal leakage in Class V cavities. Conclusion: The microleakage performance of glass-ionomer-resin composite hybrid materials was similar to those of a conventional glass-ionomer and a bonded resin composite system.

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Background: Rumenostomy may be performed for therapeutic and digestibility research purposes in bovines, small ruminants and camelids. Several studies requires romenostomy in buffaloes in order to sample ruminal content for laboratorial assays. However, complications and outcome of rumenostomy was poorly studied in buffaloes. Therefore, the aim of the current study was to describe a two-stage rumenostomy technique in buffaloes, focused on intra and post-operative period.Materials, Methods & Results: Nine Murrah buffaloes were submitted to a 36-h and 12-h of food and water fastening. The animals were given acepromazine and maintained in standing position. Flank local anesthesia was carried out. A circular skin incision was carried out in the center of the left flank, followed by divulsion of the external and internal obliques and transversus abdominus muscles, and incision of the peritoneum. Subsequently, a segment of the dorsal aspect of the rumen was grasped and pulled through the flank incision. The rumen was attached to the peritoneum and skin incision margins in four points (dorsal, ventral, cranial and caudal). Additional simple interrupted sutures attaching the rumen serosa to the skin were applied subsequently. Four additional interrupted horizontal mattress sutures were applied equidistantly, taking bites only in the skin and rumen serosa. Following 12 h, the second stage was carried out. The buffaloes were prepared and restrained as performed for the first stage. A circular flap was excised from the exteriorized rumen and the silicone romenostomy cannula was placed. Clinical parameters, postoperative recovery, weight and behavioral pain scale were assessed. Positioning and anesthesia regimen were adequate for the achievement of the procedure. However, two animals fell in the restraint chute during the first surgical stage. Mild ischemia of the exteriorized rumen segment was observed on the second surgical stage, which resulted in less hemorrhage and enhanced cannula positioning. Complete cicatrization and permanent adhesion of the rumen to the skin were achieved. No ruminal leakage to the abdominal cavity occurred. No signs of pain were reported. There were few cases of laxity of the romenostomy opening leading to drop of cannula, myiasis on the margin of the stoma site and few cases of mild ruminal content leakage on the long-term assessment.Discussion: Restraint in standing position was considered adequate, although lateral recumbence constitutes another option. However, higher risk of contamination and technical difficulties in placing the cannulas are expected if lateral recumbence is considered. In other trials using acepromazine, no accidental recumbence occurred. Xylazine was also indicated for chemical restraint of buffaloes. It is known that flexible cannulas provide better anatomic adjustment and adaptation as well as being effective for sampling ruminal content, as seen in the current study. Ruminal leakage is one of the most frequent complications of romenostomy, which may affect animal's welfare. The animals in the current study presented no variations on the body score, even though on those presenting cannula loosening or ruminal content leakage. Moreover, no significant changes of the ruminal content parameters were noticed. Myiasis was also reported following ruminal surgical interventions, which were mainly attributed to extensive breeding. Loss of the cannula, subcutaneous emphysema and suture dehiscence are common complications of romenostomy. Nonetheless, none of those complications were found on the current study. Thus, romenostomy was feasible and efficient for sampling and performing assays of the ruminal content in buffaloes.

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Veterinary Dentistry has grown considerably in recent years. This growth, associated to increase of knowledge among pet owners regarding responsible ownership of their pets, resulted in growing concern about the oral health of the animals that already can be observed at veterinary clinics. Among the oral diseases in dogs, infraorbital fistula, so called carnassial” fistula, is a periapical osteolytic lesion of the fourth premolar (4 SPM), often associated with periodontal disease. In its early stages, is characterized clinically by a swelling in the region of the jawbone before the formation of the fistula and leakage of a liquid serosanguineous or purulent secretion. Because of these clinical features, it is often misdiagnosed as a skin condition unrelated to the teeth. It is very important to obtain intraoral radiographs to confirm the diagnosis for performing the most appropriate treatment, according to the cause of the injury

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With the emergence of new filling materials with different properties and behaviors, the approach of endodontic treatment must be readjusted so that the appropriate result can be achieved. New endodontic sealers include methacrylate resin-based, plant resin-based and the evolution of epoxy-based sealers. This study verified the behavior of new materials that presents controversial results in the literature, about coronal bacterial leakage. That for, 56 single-rooted human teeth were prepared in the direction crown-apex and filled with gutta-percha points with taper of 4% using the single cone technique. Roots were divided randomly into 4 groups according to the sealer (Apexit Plus, AH Plus, EndoREZ and Polifil). After filling, the roots were incorporated in a leakage model, which upper chamber contained a suspension of Streptococcus mutans, and lower chamber a broth, leaving 3 mm of root apical portion immersed. Leakage was assessed for turbidity in lower chamber every day for 60 days. Survival analysis was performed using the nonparametric Kaplan- Meier method (p<0,05). All experimental groups presented leakage during the study’s period, however the maximum time achieve was 22 days. The medium time of leakage was: Apexit Plus 6,3 days, AH Plus 6,3 days and Polifil 5,1 days, but in EndoREZ all specimens infiltrated in the first day, presenting shorter capacity of impermeabilization compared to the other groups. Concluding that none of the sealers tested was able to prevent coronal bacterial leakage

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The internal combustion engine is a heat engine widely used in the automotive industry. In order to better understand its behavior many models in the literature have been proposed in the last years. The 0-D thermodynamic model is a fairly simple tool but it is very useful to understand the phenomenon of combustion inside the chamber of internal combustion engines. In the first phase of this work, an extensive literature review was made in order to get information about this kind of analysis and, after this, apply them in a model able to calculate the instantaneous temperature and pressure in one zone of the combustion chamber of a diesel engine. Therefore some considerations were made with the aim of increasing the accuracy of the model in predicting the correct behavior of the engine, adding the combined effects of heat transfer, leakage and injection. In the second phase, the goal was to study the internal flow of a three-dimensional model of an internal combustion engine. In order to achieve this goal the software Solidworks was used to create the geometries of an engine and the suite of softwares Ansys was used to create the moving mesh (ICEM CFD and CFX-Pre) and to solve the CFD problem (Ansys CFX code). The model was able to perform the air flow simulation during the four-stroke cycle of an engine: admission, compression, expansion and exhaust. The results obtained from both models were suitable and they open a new range of possibilities for future researches on the field

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According to the National Institute of Cancer – INCA, 466.730 new cancer cases will occur in Brazil in 2009. Prostate and Lung cancer in man are the most incident types (in exception of the non-melanoma cancer). The brachytherapy with 125-iodine sources is an important method of prostate cancer treatment. The implant with iodine-125 seeds uses aproximately 100 seeds that are imported impossibilitating the treatment in large scale. For this reason, a multidisciplinary group was created at the Energetic and Nuclear Research Institute – Radiation Technology Center (IPEN –CTR / SP) to develop a national 125-iodine source and established a facility for local production. The seeds manufacture in Brazil will diminish the cost of treatment and prostate brachytherapy will be offered to more patients. This work aim is to observe and discuss the methods used in seeds manufacture there are being developed in Brazil and to present an prostate cancer case folloied in A.C. Camargo Hospital. The 125-iodine is adsorbed in an silver wire, then deposited at titanium coat. The weld is made by an process of plasm sealing. The seeds goes through several test to guarantee that there is no leakage. The result is an high quality and cheaper product. The implant tecnique is an fast and save procedure. The medical physicst preplan the case to stipulate the quantity of seeds there will be used. At the dat of the implant the medical physicst replan the procedure due to changes of volume in the organ. That assure the correct dose distribution in the target. Besides, the 125-iodine low energy is absorbed at the volume of interrest saving sourronding healthy tissues such as the rectum and the urethra

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Pós-graduação em Cirurgia Veterinária - FCAV

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Techniques based on signal analysis for leak detection in water supply systems typically use long pressure and/or flow data series of variable length. This paper presents the feature extraction from pressure signals and their application to the identification of changes related to the onset of a leak. Example signals were acquired from an experimental laboratory circuit, and features were extracted from temporal domain and from transformed signals. Statistical analysis of features values and a classification method were applied. It was verified the feasibility of using feature vectors for distinguish data acquired in the absence or presence of a leak.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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SnO2-based varistors are strong candidates to replace the ZnO-based varistors due to ordering fewer additives to improve its electrical behavior as well as by showing similar nonlinear characteristics of ZnO varistors. In this work, SnO2-nanoparticles based-varistors with addition of 1.0 %mol of ZnO and 0.05 %mol of Nb2O5 were synthesized by chemical route. SnO2.ZnO.Nb2O5-films with 5 μm of thickness were obtained by electrophoretic deposition (EPD) of the nanoparticles on Si/Pt substrate from alcoholic suspension of SnO2-based powder. The sintering step was carried out in a microwave oven at 1000 °C for 40 minutes. Then, Cr3+ ions were deposited on the films surface by EPD after the sintering step. Each sample was submitted to different thermal treatments to improve the varistor behavior by diffusion of ions in the samples. The films showed a nonlinear coefficient (α) greater than 9, breakdown voltage (VR) around 60 V, low leakage current (IF ≈ 10-6 A), height potential barrier above 0.5 eV and grain boundary resistivity upward of 107 Ω.cm.