ObjectiveTo investigate the effects of dilution of paramagnetic contrast agent with
iodinated contrast and xylocaine on the signal intensity during magnetic resonance
arthrography, and to improve the paramagnetic contrast agent concentration
utilized in this imaging modality.Materials and MethodsSamples specially prepared for the study with three different concentrations of
paramagnetic contrast agent diluted in saline, iodinated contrast agent and
xylocaine were imaged with fast spin echo T1-weighted sequences with fat
saturation. The samples were placed into flasks and graphical analysis of the
signal intensity was performed as a function of the paramagnetic contrast
concentration.ResultsAs compared with samples of equal concentrations diluted only with saline, the
authors have observed an average signal intensity decrease of 20.67% for iodinated
contrast agent, and of 28.34% for xylocaine. However, the increased gadolinium
concentration in the samples caused decrease in signal intensity with all the
dilutions.ConclusionMinimizing the use of iodinated contrast media and xylocaine and/or the use of a
gadolinium concentration of 2.5 mmol/L diluted in saline will improve the
sensitivity of magnetic resonance arthrography.
This work shows a curvature vector sensing device based on a single long-period grating written in a commercial photosensitive optical fibre. The sensing approach uses an artificial neural network based on multilayer perceptrons for data analysis. Curvatures from 0.00 to 3.13 m −1 and angular orientations from 0 to 180 • were measured with the device, with combined standard uncertainties of 0.05 m −1 and 1.5 • , respectively. The root mean square errors for curvature and angular orientation were 0.0008 m −1 and 0.3 • in the training stage and 0.002 m −1 and 0.9 • in the test stage, respectively.
Em um cenário de controvérsias sobre composições curriculares na Educação em Ciências, evidenciam-se as abordagens temáticas e suas potencialidades concernentes à vinculação a aspectos contextuais subjacentes à ação educativa e à inter-relação entre as áreas de conhecimento. Pertinente a esse panorama, neste trabalho, analisou-se as percepções e relações estabelecidas por estudantes em abordagem temática, envolvendo material e atividades educacionais sobre o corpo humano em associação com o eletromagnetismo. Nesta pesquisa, concatenaram-se aspectos qualitativos e quantitativos, agregando a participação de discentes do 3º ano do Ensino Médio de uma instituição pública da cidade de Curitiba, no estado do Paraná, com dados constituídos por meio de questionários. As proposições de interpretações envolveram pressupostos de Análise de Conteúdo e estatística descritiva e abrangeram dois eixos: percepções sobre as composições curriculares e a aprendizagem, e as relações envolvendo conteúdos de Física associados ao corpo humano. Através dos dados levantados na intervenção em sala de aula, indícios de motivação e correlação com aspectos de aprendizagem foram evidenciados. Averiguou-se, ainda, a vinculação entre conteúdos de Física e de outras áreas de conhecimentos envolvendo a temática. Cabe salientar nesse contexto a viabilidade de abordagens temáticas para o Ensino Médio no que se refere às potencialidades de aprendizagem e de atribuição de sentido e significado às composições curriculares.
This work presents results concerning to the production and characterization of long-period gratings in optical fibres using the point-to-point writing technique with an ultraviolet laser. Long-period gratings, with a nominal period of 407 µm, were engraved in the core of hydrogen loaded photosensitive single-mode optical fibres. The loading was carried out by submitting the fibre to a pressure of 130 atm at room temperature along time intervals up to 20 days. During the writing process, long-period grating growth was monitored recording the transmission spectrum after each engraved point. After the end of the inscription process, the grating attenuation, resonant wavelength and bandwidth were still monitored along the time. Spectral changes were recorded during time intervals as longer as 595 hours, and an analysis of the grating's growth kinetic is presented. The long-period grating thermal and strain sensitivities were also determined and the results are presented. Long-period grating was also characterized for temperature changes within the range from 25 ºC to 425 ºC in consecutive up-anddown thermal cycles and hysteresis effects are discussed. The analysis of the grating strain response was done with the device submitted to longitudinal mechanical stress resulting in relative deformations ranging from 0 to 125 µε in incremental steps of 25 µε. The interplay between the cross-sensitivity is discussed as well as its role in the grating performance as a sensor.
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