Finite element studies of the mechanical behaviour of the diaphragm in normal and pathological cases

The diaphragm is a muscular membrane separating the abdominal and thoracic cavities, and its motion is directly linked to respiration. In this study, using data from a 59-year-old female cadaver obtained from the Visible Human Project, the diaphragm is reconstructed and, from the corresponding solid object, a shell finite element mesh is generated and used in several analyses performed with the ABAQUS 6.7 software. These analyses consider the direction of the muscle fibres and the incompressibility of the tissue. The constitutive model for the isotropic strain energy as well as the passive and active strain energy stored in the fibres is adapted from Humphrey's model for cardiac muscles. Furthermore, numerical results for the diaphragmatic floor under pressure and active contraction in normal and pathological cases are presented.

A reliable M-mode ultrasound protocol for the assessment of diaphragm motion

Diaphragm is the principal inspiratory muscle. Different techniques have been used to assess diaphragm motion. Among them, M-mode ultrasound has gain particular interest since it is non-invasive and accessible. However it is operator-dependent and no objective acquisition protocol has been established. Purpose: to establish a reliable method for the assessment of the diaphragmatic motion via the M-mode ultrasound.

Theoretical Analysis of Multimodal Four-Wave Mixing in Optical Microwires

Optical fiber microwires (OFMs) are nonlinear optical waveguides that support several spatial modes. The multimodal generalized nonlinear Schrodinger equation (MM-GNLSE) is deduced taking into account the linear and nonlinear modal coupling. A detailed theoretical description of four-wave mixing (FWM) considering the modal coupling is developed. Both, the intramode and the intermode phase-matching conditions is calculated for an optical microwire in a strong guiding regime. Finally, the FWM dynamics is studied and the amplitude evolution of the pump beams, the signal and the idler are analyzed.

Estudo comparativo de sistemas em aquecimento

Trabalho Final de Mestrado para obtenção do grau de Mestre em Engenharia Mecânica

Estudo de soluções de contenção periférica em função das condicionantes de execução

Dissertação de natureza científica para obtenção do grau de Mestre em Engenharia Civil

Does diaphragmatic breathing technique really improve its range of motion? An objective assessment

Purpose - To verify the results of a diaphragmatic breathing technique (DBT) on diaphragmatic range of motion in healthy subjects. Methods - A total of 51 healthy subjects (10 male; 41 female), mean age 20 years old and a body mass index (BMI) ranging from 15.6 to 34.9 kg/m2, were enrolled in this study. Diaphragmatic range of motion was assessed by M-mode ultrasound imaging. Measurements were made before and after the DBT implementation in a standard protocol, based on 3 seconds of inspiration starting from a maximum expiration. Differences between assessments were analyzed by descriptive statistics and t-test (p < 0.05). Results - Mean value range of motion before DBT was 55.3 ± 13.4 mm and after DBT was 63.8 ± 13.2 mm showing a significant improvement of 8.5 ± 14.7 mm (p < 0.001). A strong correlation between the slope and the range of motion was found (r = 0.71, p < 0.001). Conclusions - Based on ultrasound measurements, it has been proved that DBT really contributes to a higher diaphragmatic range of motion. Future studies are needed in order to understand the influence of protocol parameters (e.g. inspiration time). Clinical implications - In the contest of evidence-based practice in physiotherapy, it has been showed by objective measurements that DBT improves the diaphragm range of motion, translating into a more efficient ventilatory function and thus can be used in clinical setting. To our knowledge this is the first study to assess the effects of DBT on range of motion of diaphragm muscle with ultrasound imaging.

Equipamento de produção de água gelada para melhorar a eficácia do combate a incêndios florestais

Trabalho Final de Mestrado para obtenção do grau de Mestre em Engenharia Mecânica

Estudo de uma central hidroeléctrica com base em turbina hidráulica reversível

Trabalho Final de Mestrado para obtenção do grau de Mestre em Engenharia Mecânica

Sistema de climatização para um edifício da Rede de Energia Nacional

Trabalho Final de Mestrado para obtenção do grau de Mestre em Engenharia Mecânica

Projecto do núcleo de recreio náutico do porto de S. Roque: Ilha do Pico

Trabalho Final de Mestrado para obtenção do grau de Mestre em Engenharia Civil - Área de especialização de Hidráulica

Estudo técnico-económico para otimização do projeto e implementação de uma bomba de calor "heat machine"

Trabalho Final de Mestrado para obtenção do grau de Mestre em Engenharia Mecânica

Sistemas de bombagem de água utilizando energia solar fotovoltaica

Trabalho Final de Mestrado para obtenção do grau de Mestre em Engenharia Mecânica

Unusual cause for smoldering dysphagia

A 30-year-old black woman presented with heartburn and odynophagia. She had a 2-year history of Behçet’s disease and systemic lupus erythematosus and had been treated with colchicine, hydroxychloroquine, and sucralfate. Odynophagia was not related to the presence of oral ulcers as they were painless and when they were in remission the patient would still intermittently complain of substernal pain. The patient underwent upper digestive endoscopy that revealed only small mucosal irregularities in the upper third of the esophagus. Biopsies of these segments showed marked acanthosis and papillomatosis of the squamous epithelium as well as intense lymphoplasmacytic infiltrate with an increased number of intraepithelial lymphocytes (IEL). There were neither granulocytes nor signs of viral infection. The endoscopic findings were then attributed to regenerative changes of the epithelium and the patient was started on a proton pump inhibitor (PPI), assuming gastroesophageal reflux disease (GERD). During the following years there were flare-ups of rheumatologic disease activity due to the patient’s lack of adherence to therapy. However, there was no correlation of the patient’s maintained (although scarce) complaints of transitory dysphagia and substernal pain.