935 resultados para acoustic trauma


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It has been the main concern of CEHUM, as a Research Centre within the Humanities which operates in an inter and transdisciplinary structure to listen attentively to the “noise of the world” and attempt a global interpretation of the signs of the times issuing from the world around us, as vibrant echoes of many social and cultural pressing issues. Every year each new Colóquio de Outono attempts to give evidence of that concern through the topic chosen for debate, ample enough and challenging enough to trigger a lively multidisciplinary dialogue amongst the diff erent research groups that compose this centre, the participants and our invited guest speakers. Throughout the three days of this 16th Colóquio de Outono we had the privilege to debate the propositions of a vast number of national and international specialists in the manifold fi elds of inquiry here represented, engaging keynote speakers, project advisors, members of research teams and external researchers attached to the various research projects currently running in CEHUM, in the fi elds of literature, linguistics, philosophy, ethics, visual arts, cultural studies, music and performance. Each specifi c fi eld of studies was however never seen isolated, but always embodied in a geo-cultural context and within the scope of a wide variety of critical debates and current theories of knowledge, as a signal of our understanding of the Humanities as a rich and plural territory which engages us all, scholars, researchers, students.

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Relatamos o caso de paciente internado em nossa instituição com ruptura da válvula coronariana direita da valva aórtica, secundária a trauma torácico fechado. O ecocardiograma transesofágico identificou o local da ruptura, permitindo melhor planejamento cirúrgico.

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O infarto agudo do miocárdio pós-trauma torácico fechado (IAM pós-TTF) é complicação rara, potencialmente fatal e muitas vezes não reconhecida. A lesão cardíaca é diagnosticada em menos de 10% dos traumas torácicos fechados. A literatura médica é escassa quando se trata de IAM pós-TTF, carecendo de um protocolo fundamentado que oriente na sua identificação. Apresentamos dois casos de IAM pós-TTF em pacientes jovens, previamente hígidos, sem fatores de risco para doença arterial coronariana. Mediante a revisão de literatura, discutimos os meios diagnósticos e a orientação terapêutica. Concluímos que o médico emergencista deve estar atento para a possibilidade de IAM em pacientes vítimas de TTF, independentemente da intensidade do trauma.

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Relatamos a seguir um caso de ruptura do septo interventricular após trauma torácico automobilístico com evolução relativamente benigna a despeito da extensão da lesão anatômica.

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El control de propiedades hidrodinámicas capaces de influir en la mecánica de ruptura y poración de sistemas lamelares o membranas es de fundamental interés para diferentes aplicaciones biotecnológicas. Resulta de particular interés la conexión entre los procesos microscópicos relacionados al tipo de moléculas o unidades básicas, el orden determinado en el auto-ensamblado de las mismas y la dinámica local del sistema, con las propiedades físicas que determinan el comportamiento macroscópico bajo estimulación acústica. Resultados logrados recientemente sugieren la existencia de resonancias hidrodinámicas que podrian ser utilizadas para lograr la inestabilidad del sistema a baja potencia acústica. Se realizaran estudios experimentales utilizando principalmente técnicas que combinan resonancia magnética nuclear (RMN) y la sonicación de la muestra. También se realizarán estudios teóricos y simulaciones numéricas que permitan modelar los sistemas bajo estudio. Se propone dar continuidad al desarrollo de una técnica de relaxometría magnética nuclear en la cual se estimula acústicamente a la muestra durante el proceso de relajación magnética nuclear, y continuar la implementación de técnicas de RMN con resolución espacial que permitan complementar los estudios mencionados. Se espera comprender los mecanismos físicos que determinan la estabilidad de fases lamelares, logrando un modelo verificable y consistente que permita relacionar las propiedades mecánicas e hidrodinámicas con las propiedades de orden y dinámica molecular. Asimismo, se espera lograr avances en el desarrollo de las técnicas experimentales involucradas. La importancia del proyecto radica en el enfoque del problema. A diferencia de casi la totalidad de los estudios reportados, nuestro interés se enfoca en mecanismos de interacción entre la membrana y el campo acústico que sean eficientes a baja potencia acústica, en un régimen donde los gradientes térmicos y la cavitación sean despreciables.

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Relatamos o caso de um indivíduo do sexo masculino de 29 anos de idade, vítima de um acidente de carro no qual sofreu trauma torácico fechado, evoluindo com insuficiência cardíaca congestiva. O paciente apresentava boa saúde previamente, sem sintomas de doença cardiovascular. Na avaliação inicial, o eletrocardiograma mostrou ondas Q nas derivações precordiais e o ecocardiograma mostrou disfunção ventricular esquerda importante. A angiografia coronária mostrou uma lesão na artéria coronária descendente anterior esquerda (ADE), com acinesia da parede anterior na ventriculografia com contraste. A tomografia computadorizada por emissão de fóton único (SPECT) com Tálio-201 não mostrou viabilidade. O paciente foi mantido em tratamento clínico com boa evolução.

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As lesões da valva tricúspide decorrentes de trauma torácico penetrante são raras e frequentemente subdiagnosticadas. O objetivo deste relato é descrever um caso de insuficiência tricúspide grave secundária a acidente por arma branca com evolução insidiosa, diagnosticada 19 anos após o ocorrido. O caso enfatiza a importância do acompanhamento adequado dos pacientes vítimas de trauma torácico penetrante por longo período após a injúria, para detecção de possíveis complicações tardias do trauma.

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Surgeons may use a number of cutting instruments such as osteotomes and chisels to cut bone during an operative procedure. The initial loading of cortical bone during the cutting process results in the formation of microcracks in the vicinity of the cutting zone with main crack propagation to failure occuring with continued loading. When a material cracks, energy is emitted in the form of Acoustic Emission (AE) signals that spread in all directions, therefore, AE transducers can be used to monitor the occurrence and development of microcracking and crack propagation in cortical bone. In this research, number of AE signals (hits) and related parameters including amplitude, duration and absolute energy (abs-energy) were recorded during the indentation cutting process by a wedge blade on cortical bone specimens. The cutting force was also measured to correlate between load-displacement curves and the output from the AE sensor. The results from experiments show AE signals increase substantially during the loading just prior to fracture between 90% and 100% of maximum fracture load. Furthermore, an amplitude threshold value of 64dB (with approximate abs-energy of 1500 aJ) was established to saparate AE signals associated with microcracking (41 – 64dB) from fracture related signals (65 – 98dB). The results also demonstrated that the complete fracture event which had the highest duration value can be distinguished from other growing macrocracks which did not lead to catastrophic fracture. It was observed that the main crack initiation may be detected by capturing a high amplitude signal at a mean load value of 87% of maximum load and unsteady crack propagation may occur just prior to final fracture event at a mean load value of 96% of maximum load. The author concludes that the AE method is useful in understanding the crack initiation and fracture during the indentation cutting process.

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Magdeburg, Univ., Fak. für Elektrotechnik und Informationstechnik, Diss., 2009

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Los requisitos de los dispositivos empleados en los nuevos sistemas de telecomunicaciones son: unas avanzadas prestaciones, reducido tamaño y bajo coste. Actualmente, se utilizan filtros basados en la tecnología SAW para trabajar a frecuencias de microondas. Dado los inconvenientes que presentan dicho tipo de filtros, se pretende substituirlos por filtros basados en tecnología BAW. La topología en escalera es hasta el momento la más extendida para diseñar estos filtros.

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Sir James Lighthill proposed in 1992 that acoustic streaming occurs in the inner ear, as part of the cochlear amplifier mechanism. Here we hypothesize that some of the most ancient organisms use acoustic streaming not only for self-propulsion but also to enhance their nutrient uptake. We focus on a motile strain of Synechococcus, a yanobacteria whose mechanism for self-propulsion is not known. Molecular motors could work like piezoelectric transducers acting on the crystalline structure surrounding the outer cell membrane. Our calculations show that a traveling surface acoustic wave (SAW)could account for the observed velocities. These SAW waves will also produce a non-negligible Stokes layer surrounding the cell: motion within this region being essentially chaotic. Therefore, an AS mechanism would be biologically advantageous, enhancing localized diffusion processes and consequently, chemical reactions. We believe that acoustic streaming, produced by nanometer scale membrane vibrations could be widespread in cell biology. Other possible instances are yeast cells and erythrocytes. Flows generated by acoustic streaming may also be produced by silica coated diatoms along their raphe. We note that microelectromechanical (MEMS) acoustic streaming devices were first introduced in the 1990’s. Nature may have preceded this invention by 2.7 Gyr.

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OBJECTIVE: Past traumatic events have been associated with poorer clinical outcomes in people with bipolar disorder. However, the impact of these events in the early stages of the illness remains unclear. The aim of this study was to investigate whether prior traumatic events were related to poorer outcomes 12 months following a first episode of psychotic mania. METHODS: Traumatic events were retrospectively evaluated from patient files in a sample of 65 participants who had experienced first episode psychotic mania. Participants were aged between 15 and 28 years and were treated at a specialised early psychosis service. Clinical outcomes were measured by a variety of symptomatic and functioning scales at the 12-month time-point. RESULTS: Direct-personal traumatic experiences prior to the onset of psychotic mania were reported by 48% of the sample. Participants with past direct-personal trauma had significantly higher symptoms of mania (p=0.02), depression (p=0.03) and psychopathology (p=0.01) 12 months following their first episode compared to participants without past direct-personal trauma, with medium to large effects observed. After adjusting for baseline scores, differences in global functioning (as measured by the Global Assessment of Functioning scale) were non-significant (p=0.05); however, participants with past direct-personal trauma had significantly poorer social and occupational functioning (p=0.04) at the 12-month assessment with medium effect. CONCLUSIONS: Past direct-personal trauma may predict poorer symptomatic and functional outcomes after first episode psychotic mania. Limitations include that the findings represent individuals treated at a specialist early intervention centre for youth and the retrospective assessment of traumatic events may have been underestimated.