944 resultados para 3-DIMENSIONAL ULTRASOUND


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This paper aims to contribute to the three-dimensional generalization of numerical prediction of crack propagation through the formulation of finite elements with embedded discontinuities. The analysis of crack propagation in two-dimensional problems yields lines of discontinuity that can be tracked in a relatively simple way through the sequential construction of straight line segments oriented according to the direction of failure within each finite element in the solid. In three-dimensional analysis, the construction of the discontinuity path is more complex because it requires the creation of plane surfaces within each element, which must be continuous between the elements. In the method proposed by Chaves (2003) the crack is determined by solving a problem analogous to the heat conduction problem, established from local failure orientations, based on the stress state of the mechanical problem. To minimize the computational effort, in this paper a new strategy is proposed whereby the analysis for tracking the discontinuity path is restricted to the domain formed by some elements near the crack surface that develops along the loading process. The proposed methodology is validated by performing three-dimensional analyses of basic problems of experimental fractures and comparing their results with those reported in the literature.

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

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Lower gastrointestinal tract neoplasms are rare in domestic animals, representing 3% of all biopsies and necropsies. Our objective is to describe the histopathological and B-mode ultrasound findings in a case of duodenal adenocarcinoma in a dog, since it commonly occurs in the large intestine. On ultrasound examination, there was transmural wall thickening in the duodenum with loss of layer structure, focal peritonitis and adenopathy. Histopathological examination of the intestinal mass revealed a malignant epithelial neoplasm, densely cellular and infiltrative, extending through the lamina propria, submucosa, muscle and hypodermis, characterizing a duodenal adenocarcinoma. We conclude that adenocarcinomas may be included in the differential diagnosis of transmural lesions in the duodenum in B-mode ultrasound examinations, but a laparotomy and biopsy are required for definitive diagnosis.

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

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The present work has the scope to show the relationship between four three-dimensional waves. This fact will be made in the form of coupling, using for it the Cauchy-Riemann conditions for quaternionic functions [#!BorgesZeMarcio!#], through certain Laplace's equation in [#!MaraoBorgesLP!#]. The coupling will relate those functions that determine the wave as well as their respective propagation speeds.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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The present study aims at evaluating dimensional alteration of stone casts made from impressions with a standard irreversible hydrocolloid and an antimicrobial one. For this, an alginate without disinfectant (Type II Jeltrate) and other containing chlorhexidine (Type II Avagel) were used, which rose by the same regime of treatment: without disinfection; immersion; and spraying. A 1% sodium hypochlorite solution was used for 10 minutes. To obtain the impressions, a perforated impression tray was made from a standard metal model. After molding, the molds were washed in running water for 30 seconds to simulate removal of saliva. Then, with the exception of the control group, these molds were subjected to disinfection treatment. After 10 minutes they were washed again. 60 samples poured with type V special gypsum (Durone) were obtained, that were measured 3 times in a stereomicroscope (SZX12, Olympus) to record the average of dimensional alterations. The disinfection treatment did not bring significant changes in the models obtained from both alginate tested (standard p = 0.7102; with chlorhexidine p = 0.5832). The results showed a statistically significant and additional advantage of the traditional alginate on alginate with chlorhexidine, with respect to dimensional alteration (p < 0.05).

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ObjectiveThis study aimed to evaluate the benefit and specifically the feasibility of using ultrasound in ophthalmologic periconal block, and the occurrence of complications.Study designProspective experimental study.AnimalsTen healthy New Zealand White rabbits (6-8months of age), weighing 2.0-3.5kg.MethodsRabbits were anesthetized by intramuscular injection of acepromazine (1mgkg(-1)), ketamine (30mgkg(-1)) and xylazine (3mgkg(-1)). Ultrasound-assisted periconal block with lidocaine was performed on 18 eyes. Intraocular pressure was measured by applanation tonometry whereas corneal sensitivity was assessed using an esthesiometer, before and after each periconal anesthesia.ResultsIn all 18 eyes, it was possible to adequately visualize the needle shaft within the periconal space, as well as muscular cone, optic nerve and local anesthetic solution spread. Lidocaine 2% without epinephrine (0.790.19mL) was injected into the periconal space. There was no statistical difference between the intraocular pressure (meanSD) measured before (10.9 +/- 2.9mmHg) and after (11.9 +/- 3.8mmHg) the periconal anesthesia (p=0.38). The effectiveness of the ultrasound-assisted technique was shown according to the values for corneal sensitivity, assessed before and after periconal anesthesia (p<0.0001). Complications were not observed in this study.ConclusionsEye ultrasonography allowed visualization of all anatomic structures necessary to perform a periconal block, as well as the needle insertion and anesthetic spread in real time. Further studies are required to prove the real potential of ultrasound for reducing the incidence of complications associated with ophthalmic blocks, especially when anatomic disorders of the eye could potentially increase the risk.Clinical relevanceUltrasonography is a painless, noninvasive tool that may improve safety of ophthalmic regional blocks, potentially by reducing the prevalence of globe perforation or penetration of the optic nerve associated with the needle-based techniques.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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