1000 resultados para RESONANCE INTEGRAL
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The use of precast, prestressed concrete piles in the foundation of bridge piers has long been recognized as a valuable option for bridge owners and designers. However, the use of these precast, prestressed concrete piles in integral abutment bridges has not been widespread because of concerns over pile flexibility and the potential for concrete cracking and deterioration of the prestressing strands due to long-term exposure to moisture. This report presents the details of the first integral abutment bridge in the state of Iowa that utilized precast, prestressed concrete piles in the abutment. The bridge, which was constructed in Tama County in 2000, consists of a 110 ft. long, 30 ft. wide, single-span PC girder superstructure with a left-side-ahead 20º skew angle. The bridge was instrumented with a variety of strain gages, displacement sensors, and thermocouples to monitor and help in the assessment of structural behavior. The results of this monitoring are presented, and recommendations are made for future application of precast, prestressed concrete piles in integral abutment bridges. In addition to the structural monitoring data, this report presents the results of a survey questionnaire that had been mailed to each of the 50 state DOT chief bridge engineers to ascertain their current practices for precast, prestressed concrete piles and especially the application of these piles in integral abutment bridges.
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Desarrollo de una aplicación para responder a la necesidad del ministerio de Sanidad de informatizar todo el sistema sanitario, desde hospitales hasta farmacias.
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BACKGROUND: Conventional x-ray angiography frequently underestimates the true burden of atherosclerosis. Although intravascular ultrasound allows for imaging of coronary plaque, this invasive technique is inappropriate for screening or serial examinations. We therefore sought to develop a noninvasive free-breathing MR technique for coronary vessel wall imaging. We hypothesized that such an approach would allow for in vivo imaging of coronary atherosclerosis. METHODS AND RESULTS: Ten subjects, including 5 healthy adult volunteers (aged 35+/-17 years, range 19 to 56 years) and 5 patients (aged 60+/-4 years, range 56 to 66 years) with x-ray-confirmed coronary artery disease (CAD), were studied with a T2-weighted, dual-inversion, fast spin-echo MR sequence. Multiple adjacent 5-mm cross-sectional images of the proximal right coronary artery were obtained with an in-plane resolution of 0.5x1.0 mm. A right hemidiaphragmatic navigator was used to facilitate free-breathing MR acquisition. Coronary vessel wall images were readily acquired in all subjects. Both coronary vessel wall thickness (1.5+/-0.2 versus 1.0+/-0.2 mm) and wall area (21.2+/-3.1 versus 13.7+/-4.2 mm(2)) were greater in patients with CAD (both P:<0.02 versus healthy adults). CONCLUSIONS: In vivo free-breathing coronary vessel wall and plaque imaging with MR has been successfully implemented in humans. Coronary wall thickness and wall area were significantly greater in patients with angiographic CAD. The presented technique may have potential applications in patients with known or suspected atherosclerotic CAD or for serial evaluation after pharmacological intervention.
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PURPOSE: To evaluate the utility of inversion recovery with on-resonant water suppression (IRON) in combination with injection of the long-circulating monocrystalline iron oxide nanoparticle (MION)-47 for contrast material-enhanced magnetic resonance (MR) angiography. MATERIALS AND METhods: Experiments were approved by the institutional animal care committee. Eleven rabbits were imaged at baseline before injection of a contrast agent and then serially 5-30 minutes, 2 hours, 1 day, and 3 days after a single intravenous bolus injection of 80 micromol of MION-47 per kilogram of body weight (n = 6) or 250 micromol/kg MION-47 (n = 5). Conventional T1-weighted MR angiography and IRON MR angiography were performed on a clinical 3.0-T imager. Signal-to-noise and contrast-to-noise ratios were measured in the aorta of rabbits in vivo. Venous blood was obtained from the rabbits before and after MION-47 injection for use in phantom studies. RESULTS: In vitro blood that contained MION-47 appeared signal attenuated on T1-weighted angiograms, while characteristic signal-enhanced dipolar fields were observed on IRON angiograms. In vivo, the vessel lumen was signal attenuated on T1-weighted MR angiograms after MION-47 injection, while IRON supported high intravascular contrast by simultaneously providing positive signal within the vessels and suppressing background tissue (mean contrast-to-noise ratio, 61.9 +/- 12.4 [standard deviation] after injection vs 1.1 +/- 0.4 at baseline, P < .001). Contrast-to-noise ratio was higher on IRON MR angiograms than on conventional T1-weighted MR angiograms (9.0 +/- 2.5, P < .001 vs IRON MR angiography) and persisted up to 24 hours after MION-47 injection (76.2 +/- 15.9, P < .001 vs baseline). CONCLUSION: IRON MR angiography in conjunction with superparamagnetic nanoparticle administration provides high intravascular contrast over a long time and without the need for image subtraction.
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La presente tesis abordó un tema de gran actualidad y pertinencia social: la superación profesional de los docentes de la Enseñanza Básica Integral en atención a la diversidad de niños con necesidades educativas especiales en la República de Cabo Verde, da una respuesta encaminada a la atención a la diversidad en la escuela regular, esta como la diferencia entre culturas, lenguas, valores, sexualidad, género, religión, desarrollo y necesidades educativas especiales asociadas a una discapacidad. Esta necesidad ha sido reconocida en documentos nacionales e internacionales como la Ley General de Educación la Declaración Universal de la UNESCO. Se asume como el proceso de atención psicopedagógica encaminada a los alumnos con necesidades educativas especiales y se considera como uno de los principales retos que la sociedad actual, creciente en su pluralidad, plantea al sistema educativo, y en concreto a las instituciones escolares. Es objetivo del trabajo proponer un sistema de talleres dirigido a la superación profesional de los docentes en la atención a la diversidad de niños con necesidades educativas especiales. Desde el enfoque general dialéctico materialista y los métodos teóricos y empíricos de investigación se modela la solución del problema. Los datos obtenidos revelan las posibilidades de cambios y transformación en el objeto de estudio: la superación de los docentes en la atención a la diversidad necesidades educativas especiales regular.
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The purpose of this study was to investigate the impact of navigator timing on image quality in navigator-gated and real-time motion-corrected, free-breathing, three-dimensional (3D) coronary MR angiography (MRA) with submillimeter spatial image resolution. Both phantom and in vivo investigations were performed. 3D coronary MRA with real-time navigator technology was applied using variable navigator time delays (time delay between the navigator and imaging sequences) and varying spatial resolutions. Quantitative objective and subjective image quality parameters were assessed. For high-resolution imaging, reduced image quality was found as a function of increasing navigator time delay. Lower spatial resolution coronary MRA showed only minor sensitivity to navigator timing. These findings were consistent among volunteers and phantom experiments. In conclusion, for submillimeter navigator-gated and real-time motion-corrected 3D coronary MRA, shortening the time delay between the navigator and the imaging portion of the sequence becomes increasingly important for improved spatial resolution.
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Estudio técnico y económico de dos métodos del aprovechamiento de la materia prima en la elaboración de harina de pescado tipo integral. Contiene el balance de materia y la composición de la materia prima y sus rendimientos.
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We propose a novel compressed sensing technique to accelerate the magnetic resonance imaging (MRI) acquisition process. The method, coined spread spectrum MRI or simply s(2)MRI, consists of premodulating the signal of interest by a linear chirp before random k-space under-sampling, and then reconstructing the signal with nonlinear algorithms that promote sparsity. The effectiveness of the procedure is theoretically underpinned by the optimization of the coherence between the sparsity and sensing bases. The proposed technique is thoroughly studied by means of numerical simulations, as well as phantom and in vivo experiments on a 7T scanner. Our results suggest that s(2)MRI performs better than state-of-the-art variable density k-space under-sampling approaches.
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Acute myocarditis was until recently one of the most difficult diagnoses in cardiology. The spectrum of signs and symptoms is very wide, the usual non-invasive tests lack specificity and the myocardial biopsy is only performed in a minority of cases to confirm the diagnosis. Due to its unique ability to directly image myocardial necrosis, fibrosis and oedema, cardiac magnetic resonance (CMR) is now considered the primary tool for noninvasive assessment of patients with suspected myocarditis. CMR is also useful for monitoring disease activity under treatment. Myocarditis has been associated with the development of dilated cardiomyopathy; CMR could play a role in the follow-up of such cases to detect the progression toward a dilatative phenotype. Precise mapping of myocardial lesions with cardiac MRI is invaluable to guide myocardial biopsy and increase its diagnostic yield by improving sensitivity.
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Neste trabalho académico tivemos como objectivo verificar/conhecer a importância que as mulheres em idade reprodutiva atribuem à consulta pré-concepcional porque é uma consulta determinante para assegurar a qualidade da assistência à mulher em idade reprodutiva, porque permite obter informações incentivadoras de atitudes saudáveis no pré, durante o período de desenvolvimento fetal e no pós. Isto porque, cada vez mais a consulta pré-concepcional tem um papel fundamental na prevenção da gravidez de risco e acima de tudo na prevenção das anomalias fetais e patologias materno-fetais. A nossa pesquisa foi desenvolvida num centro de saúde de gestão pública, o Centro de Saúde Reprodutiva da Bela Vista (CSRBV), abrangendo tanto a abordagem quantitativa como a qualitativa, uma vez que os métodos de recolha e os instrumentos de recolha das informações foram: um inquérito por questionário fechado aplicado a uma amostra constituída por 52 grávidas; e ainda entrevistas exploratórias dirigidas aos enfermeiros que trabalham nesse centro. Os resultados obtidos apontam que: as gestantes não fizeram planeamento familiar; as grávidas não consideram as consultas pré-concepcionais pertinentes; 37 revelaram não ter ido à consulta pré-concepcional: as intervenções dos enfermeiros incidem sobre a avaliação de risco pré-concepcional e ainda aconselham-nas a terem cuidados com a alimentação, a praticarem exercício físico e a evitarem o consumo de bebidas alcoólicas, drogas ilícitas e tabaco. Embora a consulta pré-concepcional seja importante, ela aparece incluída nas consultas de planeamento familiar e o CSRBV revela que existe uma fraca adesão na procura da consulta pré-concepcional, chegando mesmo a não existir dados estatísticos que confirmam a realização dessa consulta no CSRBV, e ainda, não dispor de uma ficha para o atendimento de mulheres em idade reprodutiva que pretendam esse serviço. Ora, isso revela: a necessidade de ser divulgada e que as mulheres sejam sensibilizadas para que procurem esse tipo de serviços; que o CSRBV crie um sistema de atendimento próprio para as consultas pré-concepcionais; criar as condições adequadas para que haja mais adesão de mulheres para as consultas pré-concepcionais; identificar as razões pelas quais as mulheres que procuram o CSRBV não vão às consultas pré-concepcionais. Palavras-
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Prefacio sobre el monitoreo sobre el impacto del El Niño desde 1982 hasta 1983 cuando su nivel fue extremadamente intenso.
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O cálculo do valor da derivada de um integral ocorre com certa frequência na vida profissional de físicos, químicos, engenheiros, economistas ou biólogos. É frequente, contudo, surgir alguma dificuldade no decurso da sua aprendizagem. Este texto, assente na doutrina essencial e desenvolvido através de um conjunto vasto de exemplos significativos, visa, precisamente, ajudar os estudantes universitários de cursos de licenciatura diversos a ultrapassar os obstáculos referidos, assim conseguindo dominar um tema que é tão simples quão importante.