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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Investigation of Blast Load Characteristics On Lung Injury

Josey, Tyson 19 March 2010 (has links)
In many parts of the world, civilians and peacekeepers are exposed to potentially serious injury from blasts and explosions. Providing insight into the trauma thresholds for blast injury is necessary for the development of blast protection equipment and identification and subsequent treatment of blast injury. [Phillips, 1988] Blast injury can be categorized as primary, secondary, tertiary, quaternary and quinernary, corresponding to different aspects of the blast loading and injury mechanisms. Primary blast injury occurring in the lungs is of importance, since lung injury results in one of the highest rate of blast mortality. Much of the existing blast injury data was obtained from animal testing with sheep and subsequently extrapolated to humans using scaling techniques. More recently, mathematical, experimental and numerical models have been developed and employed to investigate blast injury. In this study, a detailed finite element model of a sheep thorax and human thorax (developed at the University of Waterloo) was used to predict primary blast lung injury based on a range of blast loading conditions. The models were developed based on available anatomical data and material properties to model the organs and tissues, and were evaluated using the LS-Dyna explicit finite element code. The models were previously validated for the prediction of lung PBI using Friedlander-type blast waves. All results were compared to existing literature to further verify and validate the numerical models as wells as to provide insight on the effect of loading conditions on blast injury. The blast loading input for these simulations used idealized blast waves, based on a blast physics approach. Blast loads were verified using the Chinook CFD software. The effects of idealized blast waves on predicted lung injury were investigated to determine the importance of peak pressure, blast wave duration and impulse. The duration and peak pressures for the waves were selected based on the Bowen and UVa curves, and included a right angle triangular shape and a square wave to allow for the different parameters to be considered. These results were compared to the Bowen and revised Bowen injury models. The results show that the peak overpressure is dominant in predicting injury for blast loads with long durations (>8 ms). The impulse was dominant in predicting injury for blast loads with short durations (<1 ms). For blasts loads with intermediate durations (1 ms < 8 ms) both the shape of the blast load wave and peak overpressure play a role in primary blast lung injury. The effect of orientation of the body position on primary blast lung injury was investigated. Simulations were performed using the sheep and human numerical models along with a model of a commonly used experimental device, the Blast Test Device (BTD) cylinder. These models were oriented in different positions by rotating the body relative to the blast flow. Injury results for the BTD were calculated using the Injury 8.1 injury prediction software. The BTD simulations served several purposes; it was used as a reference for the human and sheep simulations and its effectiveness as a tool to predict body orientation was evaluated. In general, all of the models predicted appropriate and similar levels of injury for the body in its default orientation, and these predictions were comparable to the accepted injury levels for this insult. For other orientations the BTD was not able to predict the appropriate blast injury. This highlighted the importance of proper placement and orientation of the BTD when used in simulations or physical experiments. The overall injury (based on the results from the right and left lung) predicted by the sheep and human thorax was similar for all orientations. However, very different results were obtained when the predicted injury for the right and left lungs was compared. The differences between the sheep and the human were examined and the differences in injury between the right and left lung is a result of the differences in anatomy between the two species. This study has evaluated the importance of blast wave parameters in predicting primary blast injury, an important consideration for the improvement of blast protection, and the effect of body orientation on primary blast injury, an important consideration for experimental testing and a starting point for the evaluation of complex blast loading. Future work will focus on the evaluation of injury in complex blast environments.
12

Investigation of Blast Load Characteristics On Lung Injury

Josey, Tyson 19 March 2010 (has links)
In many parts of the world, civilians and peacekeepers are exposed to potentially serious injury from blasts and explosions. Providing insight into the trauma thresholds for blast injury is necessary for the development of blast protection equipment and identification and subsequent treatment of blast injury. [Phillips, 1988] Blast injury can be categorized as primary, secondary, tertiary, quaternary and quinernary, corresponding to different aspects of the blast loading and injury mechanisms. Primary blast injury occurring in the lungs is of importance, since lung injury results in one of the highest rate of blast mortality. Much of the existing blast injury data was obtained from animal testing with sheep and subsequently extrapolated to humans using scaling techniques. More recently, mathematical, experimental and numerical models have been developed and employed to investigate blast injury. In this study, a detailed finite element model of a sheep thorax and human thorax (developed at the University of Waterloo) was used to predict primary blast lung injury based on a range of blast loading conditions. The models were developed based on available anatomical data and material properties to model the organs and tissues, and were evaluated using the LS-Dyna explicit finite element code. The models were previously validated for the prediction of lung PBI using Friedlander-type blast waves. All results were compared to existing literature to further verify and validate the numerical models as wells as to provide insight on the effect of loading conditions on blast injury. The blast loading input for these simulations used idealized blast waves, based on a blast physics approach. Blast loads were verified using the Chinook CFD software. The effects of idealized blast waves on predicted lung injury were investigated to determine the importance of peak pressure, blast wave duration and impulse. The duration and peak pressures for the waves were selected based on the Bowen and UVa curves, and included a right angle triangular shape and a square wave to allow for the different parameters to be considered. These results were compared to the Bowen and revised Bowen injury models. The results show that the peak overpressure is dominant in predicting injury for blast loads with long durations (>8 ms). The impulse was dominant in predicting injury for blast loads with short durations (<1 ms). For blasts loads with intermediate durations (1 ms < 8 ms) both the shape of the blast load wave and peak overpressure play a role in primary blast lung injury. The effect of orientation of the body position on primary blast lung injury was investigated. Simulations were performed using the sheep and human numerical models along with a model of a commonly used experimental device, the Blast Test Device (BTD) cylinder. These models were oriented in different positions by rotating the body relative to the blast flow. Injury results for the BTD were calculated using the Injury 8.1 injury prediction software. The BTD simulations served several purposes; it was used as a reference for the human and sheep simulations and its effectiveness as a tool to predict body orientation was evaluated. In general, all of the models predicted appropriate and similar levels of injury for the body in its default orientation, and these predictions were comparable to the accepted injury levels for this insult. For other orientations the BTD was not able to predict the appropriate blast injury. This highlighted the importance of proper placement and orientation of the BTD when used in simulations or physical experiments. The overall injury (based on the results from the right and left lung) predicted by the sheep and human thorax was similar for all orientations. However, very different results were obtained when the predicted injury for the right and left lungs was compared. The differences between the sheep and the human were examined and the differences in injury between the right and left lung is a result of the differences in anatomy between the two species. This study has evaluated the importance of blast wave parameters in predicting primary blast injury, an important consideration for the improvement of blast protection, and the effect of body orientation on primary blast injury, an important consideration for experimental testing and a starting point for the evaluation of complex blast loading. Future work will focus on the evaluation of injury in complex blast environments.
13

Ověření interakce genotypu a prostředí na dosahované parametry užitkovosti testovaných hybridních kombinací prasat / Attestation of genotyp interaction and enviroment reaching parameters efficiency tested hybrid combination of pigs

PUNDA, Luboš January 2008 (has links)
My thesis addresses gradeation of pig races and how this gradeation influences final hybrids interaction of genotyps and enviroment.. During testing is being watched slaughter weight, weight of the right side at cold, slaughter lenght torso , height of the ridge fat and the area m.l.l.t..
14

Efeito da instrução para ativação consciente dos músculos do abdômen sobre a ativação dos músculos escapulotorácicos / Instruction for conscious contraction of the abdominal muscles increases the scapular muscles activation

Angie Stephanie Vega Toro 17 August 2015 (has links)
Introdução: O objetivo desse estudo foi investigar o efeito da instrução para ativação consciente da musculatura abdominal sobre a atividade dos músculos escapulotorácicos durante exercícios de ombro. Métodos: Foram avaliados sessenta e cinco indivíduos assintomáticos do sexo feminino e masculino (média de idade de 23,5 ± 3 anos). Cinco exercícios enfocados no músculo serrátil anterior foram avaliados antes e depois do comando verbal e do estímulo táctil para ativação da musculatura abdominal. Foi utilizado o teste ANOVA para medidas repetitivas com teste Bonferroni post-hoc para comparar os valores eletromiográficos normalizados. Tamanhos de efeito com magnitudes moderadas e grandes foram considerados indicadores de significância em termos práticos. Resultados: Ativação consciente dos músculos abdominais resultou em um incremento significativo (p<,05) na atividade eletromiográfica dos músculos serrátil anterior e trapézio em suas fibras descendente, transversa e ascendente durante os exercícios dinâmicos (Wall Slide, Wall Press e Knee Push). A instrução aumentou a atividade eletromiográfica somente do músculo serrátil anterior durante os exercícios isométricos (Inferior Glide e Isometric Low Row). Conclusão: Ativação consciente dos músculos abdominais incentivada por comando verbal e estímulo tátil foi efetiva para incrementar a ativação dos músculos escapulotorácicos durante exercícios de ombro, principalmente para o músculo serrátil anterior com um tamanho de efeito de moderado a grande. / Introduction: The purpose of this study was to investigate the effect of the instruction for conscious contraction of the abdominal muscles on the scapulothoracic muscles activation during shoulder exercises. Methods: Sixty healthy male and female subjects (mean age 23.5 ± 3 years) volunteered for this study. Five exercises focusing on the serratus anterior muscle were assessed before and after standardized verbal, and tactile feedback applied to encourage abdominal muscle contraction. Repeated measures ANOVA and Bonferroni post-hoc test were used to compare normalized EMG amplitudes. Moderate and large magnitudes of effect size were considered indicators of the practical significance of our findings. Results: Conscious contraction of the abdominal muscles resulted in significant increase (p<.05) in serratus anterior, upper, middle and lower trapezius EMG amplitude, during dynamic exercises (Wall Slide, Wall Press, and Knee Push). Instruction increased EMG amplitude only for serratus anterior muscle during isometric exercises (Inferior Glide and Isometric Low Row). Conclusion: Conscious activation of the abdominal muscles, encouraged by verbal and tactile feedback was effective to increase the activation of periscapular muscles during shoulder exercises, in particular, the serratus anterior with large and moderate magnitudes of effect size.
15

Kontinuität, Verdichtung, Synchronizität: Zu den großformalen Funktionen des gepressten Bogenstrichs in Helmut Lachenmanns Streichquartetten

Egger, Elisabeth 10 July 2023 (has links)
Helmut Lachenmann’s three string quartets Gran Torso. Musik für Streichquartett (1970/71 with later revisions), »Reigen seliger Geister« (1989) and »Grido« (2000/2001, rev. 2002) introduce a huge variety of extended playing techniques that are first listed systematically allowing for a comparison between the three works on a purely technical level. It becomes obvious that most of the extended techniques are introduced in the first quartet and that the subsequent quartets show increasingly smaller selections of these techniques. This especially applies to the most prominent of these techniques: the pressed bow, described by the composer as »rattling«, which symbolizes Lachenmann’s sound world like no other technique. Although the statistics again show the highest degree of timbral differentiation in the first quartet, the pressed bow indeed takes a crucial formal function in all three works. Each quartet includes a relatively long section or field in which this technique dominates. Although the transformation processes by which these fields are integrated show some degree of similarity, a separate predominant function can be discerned for each field. In Gran Torso, the pressed bow section is part of a complex continuous transformation from »tenuto« sounds to single impulses, not least due to its »perforated« sound quality. Whereas this transformation integrates a huge variety of different timbres, »Reigen seliger Geister« condenses the music to two main sound qualities, »flautato« sounds and pizzicato-impulses. The pressed bow field here forms part of a much more concentrated large-scale development and most prominently figures in the retransition from pizzicato-chords to »toneless« impulses towards the end of the piece. In »Grido«, the pressed bow fields integrate other playing techniques as well as pitched sounds, and can be characterized by a tendency towards rhythmic and pitch-related synchronicity that also describes a large-scale formal tendency in this work. Except for the pressed bow sections, the musical flow in this work cannot be characterised by playing techniques anymore, but might be divided into »calm« and »agitated« fields that are interconnected by the »rattling fields«. The analysis provides evidence for the argument that the pressed bow technique, which often was misunderstood as a simple »negation« of beautiful sound, fulfills an essential structural function in Lachenmann’s music.
16

Numerical Computations of Action Potentials for the Heart-torso Coupling Problem

Rioux, Myriam 10 January 2012 (has links)
The work developed in this thesis focusses on the electrical activity of the heart, from the modeling of the action potential originating from cardiac cells and propagating through the heart, as well as its electrical manifestation at the body surface. The study is divided in two main parts: modeling the action potential, and numerical simulations. For modeling the action potential a dimensional and asymptotic analysis is done. The key advance in this part of the work is that this analysis gives the steps to reliably control the action potential. It allows predicting the time/space scales and speed of any action potential that is to say the shape of the action potential and its propagation. This can be done as the explicit relations on all the physiological constants are defined precisely. This method facilitates the integrative modeling of a complete human heart with tissue-specific ionic models. It even proves that using a single model for the cardiac action potential is enough in many situations. For efficient numerical simulations, a numerical method for solving the heart-torso coupling problem is explored according to a level set description of the domains. This is done in the perspective of using directly medical images for building computational domains. A finite element method is then developed to manage meshes not adapted to internal interfaces. Finally, an anisotropic adaptive remeshing methods for unstructured finite element meshes is used to efficiently capture propagating action potentials within complex, realistic two dimensional geometries.
17

Numerical Computations of Action Potentials for the Heart-torso Coupling Problem

Rioux, Myriam 10 January 2012 (has links)
The work developed in this thesis focusses on the electrical activity of the heart, from the modeling of the action potential originating from cardiac cells and propagating through the heart, as well as its electrical manifestation at the body surface. The study is divided in two main parts: modeling the action potential, and numerical simulations. For modeling the action potential a dimensional and asymptotic analysis is done. The key advance in this part of the work is that this analysis gives the steps to reliably control the action potential. It allows predicting the time/space scales and speed of any action potential that is to say the shape of the action potential and its propagation. This can be done as the explicit relations on all the physiological constants are defined precisely. This method facilitates the integrative modeling of a complete human heart with tissue-specific ionic models. It even proves that using a single model for the cardiac action potential is enough in many situations. For efficient numerical simulations, a numerical method for solving the heart-torso coupling problem is explored according to a level set description of the domains. This is done in the perspective of using directly medical images for building computational domains. A finite element method is then developed to manage meshes not adapted to internal interfaces. Finally, an anisotropic adaptive remeshing methods for unstructured finite element meshes is used to efficiently capture propagating action potentials within complex, realistic two dimensional geometries.
18

Numerical Computations of Action Potentials for the Heart-torso Coupling Problem

Rioux, Myriam 10 January 2012 (has links)
The work developed in this thesis focusses on the electrical activity of the heart, from the modeling of the action potential originating from cardiac cells and propagating through the heart, as well as its electrical manifestation at the body surface. The study is divided in two main parts: modeling the action potential, and numerical simulations. For modeling the action potential a dimensional and asymptotic analysis is done. The key advance in this part of the work is that this analysis gives the steps to reliably control the action potential. It allows predicting the time/space scales and speed of any action potential that is to say the shape of the action potential and its propagation. This can be done as the explicit relations on all the physiological constants are defined precisely. This method facilitates the integrative modeling of a complete human heart with tissue-specific ionic models. It even proves that using a single model for the cardiac action potential is enough in many situations. For efficient numerical simulations, a numerical method for solving the heart-torso coupling problem is explored according to a level set description of the domains. This is done in the perspective of using directly medical images for building computational domains. A finite element method is then developed to manage meshes not adapted to internal interfaces. Finally, an anisotropic adaptive remeshing methods for unstructured finite element meshes is used to efficiently capture propagating action potentials within complex, realistic two dimensional geometries.
19

Efeito em curto prazo da corrente interferencial associado a cinesioterapia no tronco de paciente com acidente vascular encefálico

Andrade, Daniela da Costa Maia de 21 February 2018 (has links)
Introduction: Among the main causes of disability associated with stroke, are: impairment of voluntary movements, spasticity, pain and loss of selective activity of muscles responsible for trunk control. The use of interferential current (IFC) in stroke patients has been recently reported in the literature for managing pain and spasticity. Aims: 1. to identify the evidence from studies evaluating the effects of IFC in patients with central neurological diseases (a systematic review); 2. To determine the short-term effect of IF associated with kinesiotherapy on pain of stroke patients; 3. To investigate the short term effects of IFC associated with kinesiotherapy on motor performance and functional gains of the trunk of patients with stroke. Methods: 1) A systematic review of clinical trials on 8 databases (Medline, Scopus, Science Direct, Web of Science, CINAHL, Scielo, Cochrane Central Register and PEDro) was conducted by two investigators by using the following key-words: interferential current OR interferential current therapy OR interferential electrical stimulation OR interferential electrical stimulation therapy OR interferential therapy OR interferential stimulation. The Cochrane collaboration tool was used for methodological quality analysis. 2 and 3) A randomized, double-blinded, placebo-controlled, crossover-type clinical trial was performed. 36 stroke patients were recruited and randomly included in one of two groups: active IFC group (IFC application + kinesiotherapy of trunk) and placebo IFC group (30 minutes of placebo IFC + kinesiotherapy of trunk). Both groups received 10 session of treatment, twice a week, for 60 minutes, with 05 sessions at each treatment group and a washout period of one week between treatments. Results: 1) 2004 studies were found, but only two were included based on the proposed inclusion criteria. After one single session, IFC was effective in reducing pain and spasticity and at improving balance, gait and range of motion of stroke patients. 2 and 3) there was improvement in pain during movement, pain catastrophizing and reaching of the affected member, when comparing pre and post treatment averages. There was no change in fatigue, self-esteem, motivation, trunk control, posture, flexibility and muscle tone in both groups. Conclusion: IFC might have influenced the improvements in trunk control and motor performance of stroke patients when associated with kinesiotherapy. It is recommended that new studies with a higher number of sessions be conducted to better clarify the effects of IFC associated with kinesiotherapy. / Introdução: Entre as principais causas de incapacidades do AVE podemos citar: o comprometimento dos movimentos voluntários, a espasticidade, a dor e a perda da atividade seletiva dos músculos responsáveis pelo controle do tronco. O uso da corrente interferencial (CI) em pacientes com AVE tem sido reportado recentemente na literatura científica, na prática isolada, no tratamento da dor e na espasticidade. Objetivos: 1. Identificar a evidência dos estudos que avaliaram os efeitos da CI em pacientes com doenças neurológicas centrais (revisão sistemática); 2. Determinar o efeito da CI associado a cinesioterapia na dor dos pacientes com AVE; 3. Investigar a performance motora e ganhos funcionais do tronco dos pacientes com AVE após aplicação de CI associado a cinesioterapia. Método: 1) busca sistemática de estudos em 8 bases de dados (Medline, Scopus, Science Direct, Web of Science, CINAHL, Scielo, Cochrane Central Register e PEDro) realizada por dois investigadores, através dos descritores interferential current OR interferential current therapy OR interferential electrical stimulation OR interferential electrical stimulation therapy OR interferential therapy OR interferential stimulation. Para avaliação metodológica desses estudos, foi utilizada a ferramenta da Colaboração Cochrane. 2 e 3) Ensaio clínico randomizado, controlado por placebo e duplamente encoberto, do tipo crossover. Foram recrutados 36 pacientes com AVE, que foram aleatoriamente incluídos em um dos dois grupos de estudo: grupo CI Ativa (aplicação de CI por 30 minutos + cinesioterapia de tronco) e grupo CI Placebo (placebo da CI + cinesioterapia de tronco). Ambos os grupos receberam intervenção por 10 sessões, duas vezes por semana, 60 minutos, sendo 05 sessões para cada forma de tratamento e um período de washout de uma semana. Resultados: 1) Foram encontrados 2004 estudos, porém apenas dois artigos foram incluídos por seguirem os critérios de inclusão propostos. Após administração única, a CI mostrou-se eficaz na redução da dor, da espasticidade e na melhora do equilíbrio, da marcha e da amplitude de movimento de ombro de pacientes pós AVE. 2 e 3). Houve melhora na dor em movimento, catastrofização da dor e no alcance para o lado acometido quando comparadas as médias pré e pós-tratamento. Não houve alteração da fadiga, da autoestima, da motivação, do controle de tronco, da postura, da flexibilidade e do tônus em ambos os grupos. Conclusão: A CI pode ter influenciado a melhora do tronco e performance motora de pacientes pós AVE associado a cinesioterapia. Recomenda-se, assim, a realização de novos estudos com um maior número de sessões para melhor esclarecer os efeitos da CI associada a cinesioterapia. / São Cristóvão, SE
20

Numerical Computations of Action Potentials for the Heart-torso Coupling Problem

Rioux, Myriam January 2012 (has links)
The work developed in this thesis focusses on the electrical activity of the heart, from the modeling of the action potential originating from cardiac cells and propagating through the heart, as well as its electrical manifestation at the body surface. The study is divided in two main parts: modeling the action potential, and numerical simulations. For modeling the action potential a dimensional and asymptotic analysis is done. The key advance in this part of the work is that this analysis gives the steps to reliably control the action potential. It allows predicting the time/space scales and speed of any action potential that is to say the shape of the action potential and its propagation. This can be done as the explicit relations on all the physiological constants are defined precisely. This method facilitates the integrative modeling of a complete human heart with tissue-specific ionic models. It even proves that using a single model for the cardiac action potential is enough in many situations. For efficient numerical simulations, a numerical method for solving the heart-torso coupling problem is explored according to a level set description of the domains. This is done in the perspective of using directly medical images for building computational domains. A finite element method is then developed to manage meshes not adapted to internal interfaces. Finally, an anisotropic adaptive remeshing methods for unstructured finite element meshes is used to efficiently capture propagating action potentials within complex, realistic two dimensional geometries.

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