University of Macau / Faculty of Science and Technology. / Department of Electromechanical Engineering

"The class IX myosin is a member of the myosin superfamily and found in variety of tissues. Myosin IX is quite unique among the myosin superfamily in that the tail region contains a GTPase activating protein (GAP) domain for the small GTP-binding protein, Rho. Recently it was reported that myosin IX shows processive movement that travels on an actin filament for a long distance. This was an intriguing discovery, because myosin IX is a “single-headed” myosin unlike other processive myosins which have “double-headed” structure. It has been thought that “processive” motors walk on their track with their two heads, thus traveling for a long distance. Therefore, it is reasonable to expect that the processive movement of single headed myosin IX is based on the unique feature of myosin IX motor function. In this study, I investigated the mechanism of processive movement of single-headed myosins by analyzing the mechanism of ATPase cycle of myosin IX that is closely correlated with the cross-bridge cycle (the mechanical cycle of actomyosin). In the first part, I performed the transient enzyme kinetic analysis of myosin IX using the motor domain construct to avoid the complexity raised by the presence of the tail domain. It was revealed that the kinetical characteristics of myosin IX ATPase is quite different from other processive myosins. It was particularly notable that the affinity of the weak actin binding state of Myosin IX was extremely high comparing with known myosins. It is thought that the high affinity for actin throughout the ATPase cycle is a major component to explain the processive movement of myosin IX. In the second part of this study, I cloned full length human myosin IX construct to further investigate the regulation of motor activity of myosin IX. It was revealed that the basal ATPase activity but not the actin dependent ATPase activity of myosin IX is inhibited by its tail region. Furthermore full-length myosin IX is regulated by calcium, presumably due to the calcium binding to the CaM light chain. These result suggest that the tail domain serves as a regulatory component of myosin IX."

Orientador : Douglas Eduardo Zampieri / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Campinas / Made available in DSpace on 2018-09-11T20:38:46Z (GMT). No. of bitstreams: 1 Barbieri_Nilson_M.pdf: 5005717 bytes, checksum: 9ef58d77d90130447edcb1a28f47315c (MD5) Previous issue date: 1989 / Resumo: Analisa-se o comportamento dinamico de um veiculo de quatro rodas através de um modelo com sete graus de liberdade. Primeiramente estuda-se o comportamento próprio do veículo para as duas condições de carga, descarregado e carregado, através da obtenção dos autovalores e autovetores para as duas situações. Depois estuda-se o comportamento do veículo contendo suspensão passiva convencional, trafegando por uma via reta e com perfis deterministicos das irregularidades da via modeladas por funções trigonométricas, no caso, perfis senoidais. Adota-se como critério de análise o deslocamento e a aceleração do centro de gravidade do veículo para diferentes velocidades do mesmo. Um sistema de suspensão com molas a gás é, então modelado e ajustado ao veículo. A resposta a uma excitação transiente é analisada para três tipos de suspensão: passivo, com molas a gás e semi-ativo com molas a gás / Abstract: The theoretical dynamical behaviour of a four wheel car model is analysed. The physical model with seven degrees of freedom is chosen and after some simplifications the corresponding mathematical model is established. First is studied the dynamical eigenbehaviour of the model for both unloaded and loaded conditions through the obtention of the eigenvalues and eigenvestors in different situations: changing the spring stiffness coefficients and the damping coefficient of the dampers (suspensions). Subsequently it is analysed the behaviour of the vehicle with conventional passive suspension moving on a straight road. This road has a deterministic profile of irregularities. This profile is modeled with trigonometric functions, in this case, sinusoid profile. The analysis criteria adopted are: displacement and the aceleration of the gravity center for different speeds of the vehicle. A gas spring suspension system is modeled and fitted to the vehicle. Is this way, it is analysed the behaviour of the vehicle when crossing a ramp with three different suspension types: conventional passive, passive and semi-active with gas spring, in both unloaded and loaded conditions / Mestrado / Mestre em Engenharia Mecânica

Thesis (Ed.D.)--Boston University.

Dual-task studies have shown higher sensitivity for stimuli presented at the targets of upcoming actions. Generally, movement outcome feedback is also obtained at action targets. This thesis examined whether attention is directed to action targets for the purpose of action selection, as previously concluded, or if attention is directed to monitor feedback about movement outcomes as supported by skilled-action research. Across seven experiments, participants executed either a pointing movement (Experiments 1 – 5) or a saccade (Experiments 6 and 7), while simultaneously identifying a discrimination target ('E' or '3') among distractors (2s and 5s). Action targets were generally cued by a central arrow. Discrimination target identification accuracy measured attention allocation. Crucially, movement accuracy feedback was presented at a spatially separate location from the action target. It was found that during the planning of goal-directed actions, attention is allocated to monitor movement outcomes, even if this information is provided at a spatially separate location from the action target. Attending the separate feedback location resulted in slower reaction times and less accurate pointing. Clear and consistent perceptual enhancement was also demonstrated at the action target location, even when no intrinsic or extrinsic feedback about the action could have been gained from attending there. Specific to saccades, it was found that attention is allocated before saccade execution to both the saccade goal and to the predicted future retinal location of feedback information. Lastly, perceptual performance is greater in general when participants perform the dual-task visually open-loop, that is without visual feedback from the moving hand. These results are novel in showing that attention appears to be required for action target selection, independently of the need to monitor expected locations of feedback.

To design a robust controller for active suspension systems is very important for guaranteeing the riding comfort for passengers and road handling quality for a vehicle. In this thesis, the mathematical model of full vehicle nonlinear active suspension systems with hydraulic actuators is derived to take into account all the motions of the vehicle and the nonlinearity behaviours of the active suspension system and hydraulic actuators. Four robust control types are designed and the comparisons among the robustness of those controllers against different disturbance types are investigated to select the best controller among them. The MATLAB SIMULINK toolboxes are used to simulate the proposed controllers with the controlled model and to display the responses of the controlled model under different types of disturbance. The results show that the neurofuzzy controller is more effective and robust than the other controller types. The implementation of the neurofuzzy controller using FPGA boards has been investigated in this work. The Xilinx ISE program is employed to synthesis the VHDL codes that describe the operation of the neurofuzzy controller and to generate the configuration file used to program the FPGA. The ModelSim program is used to simulate the operation of the VHDL codes and to obtain the expected output data of the FPGA boards. To confirm that FPGA the board used as the neurofuzzy controller system operated as expected, a MATLAB script file is used to compare the set of data obtained from the ModelSim program and the set of data obtained from the MATLAB SIMULINK model. The results show that the FPGA board is effective to be used as a neurofuzzy controller for full vehicle nonlinear active suspension systems. The active suspension system has a great performance for vibration isolation. However the main drawback of the active suspension is that it is high energy consumptive. Therefore, to use this suspension system in the proposed model, this drawback should be solved. Electromagnetic actuators are used to convert the vibration energy that arises from the rough road to useful electrical energy to reduce the energy consumption by the active suspension systems. The results show that the electromagnetic devices act as a power generator, i.e. the vibration energy excited by the rough road surface has been converted to a useful electrical energy supply for the actuators. Furthermore, when the nonlinear damper models are replaced by the electromagnetic actuators, riding comfort and the road handling quality are improved. As a result, two targets have been achieved by using hydraulic actuators with electromagnetic suspension systems: increasing fuel economy and improving the vehicle performance.

Dissertação (Mestrado em Engenharia Mecânica) - Centro Universitário da FEI, São Bernardo do Campo, 2014

Although the management of Motor Neuron Disease (MND) remains devoid of a cure, persons affected by this devastating condition are nonetheless entitled to the best quality care that is available. A paucity of information exists documenting the perceptions of healthcare consumers regarding the management that is provided. In addition optimal healthcare comprises an intricate interaction of patient-centred care, patient-centred communication, and bioethical practice, and when these three dimensions are implemented according to acceptable standards, high-quality healthcare is perceived by the healthcare consumer. Given however the socio-political challenges that face healthcare systems, the management of MND needs to be considered against current trends in service delivery and the need for evidence-based medicine. An exploratory study was therefore conducted to investigate the perceptions of persons with MND and their family members regarding current medical and rehabilitative management. The sample comprised six persons with MND who presented with a communication impairment, as well as six family members. Participants’ perceptions were elicited through the use of a semi-structured interview schedule, and questions focused on healthcare professionals’ behaviours during healthcare encounters. In addition emphasis was placed on the potential of the communication impairment to influence management. A standardised dysarthria assessment was conducted to characterise the nature of the speech impairment in each person with MND. Qualitative responses obtained from the interviews were analysed in accordance with a matrix-based approach, while quantitative data from the dysarthria assessment were analysed using descriptive statistics. Despite individual variability, perceptions of both persons with MND and their family members revealed general dissatisfaction with regard to medical and rehabilitative management. The majority of persons with MND were not referred for intervention following diagnosis, and the recommended team approach for the management of MND was absent. In addition the bioethical practice of many healthcare professionals was deemed questionable, and the communication impairment was perceived to impose a significant burden on the healthcare encounter. Furthermore all participants perceived a lack of available support systems for persons with MND, and it was thus not uncommon for individuals to pursue complementary and alternative medicine. South Africa’s current healthcare climate also appeared to further limit healthcare for this clinical population. In an attempt to improve the management of MND, implications are provided in terms of health communication, intervention, bioethical practice, and support systems. A proposed new framework of ideal service delivery for healthcare consumers of MND management is also presented. Further implications are outlined with regard to the need for innovative models of service delivery in South Africa’s healthcare context, as well as the role of speech-language pathologists, other healthcare professionals, policy makers, and educators in the improvement of the medical and rehabilitative management of MND. Finally theoretical implications and implications for future research are also documented.

Digitized by Kansas Correctional Industries

Il est classiquement admis que le cortex moteur des primates est organisé topographiquement en lien avec le contrôle des différentes parties du corps. Il a également été suggéré que différentes zones de cette aires corticales pourraient être impliquées dans différents processus de préparation motrice. Suivant cette dernière hypothèse, cette thèse a pour objectif d’étudier les modulations spatiales et temporelles de l’activité neuronale du cortex moteur au cours de la préparation et de l’exécution de mouvements de saisie manuelle. Trois singes ont été entraînés à réaliser une tâche pré-indicée de saisie manuelle. Chez chaque animal, une matrice d’électrodes a été implantée chroniquement dans le cortex moteur. Dans une première étude, nous avons démontré que les modulations d’activité associées à différents processus préparatoires sont localisées dans différentes zones du cortex moteur. Ces zones seraient activées séquentiellement au cours de la préparation motrice suivant une alternance de phases de traitement stationnaire et de propagation dynamique. Dans une seconde étude, nous avons exploré les interactions neuronales par l’utilisation de la mesure de corrélation de variabilité (rsc) entre paires de neurones. Cette deuxième étude a fait ressortir 3 résultats principaux. Les valeurs de rsc sont plus élevées au cours de la préparation du mouvement que lors de son exécution. Elles diminuent avec la distance qui sépare les neurones. Elles sont plus importantes entre interneurones qu’entre neurones supposés pyramidaux. L’ensemble de ces observations ont été discutées en lien avec différentes modèles d’organisation spatiale des aires motrices corticales. / The motor cortex follows a somatotopic organization in which the different body parts are controlled by distinct cortical zones. It has also been proposed that different spatial zones of this cortical area could be involed in distinct processes of motor preparation. Following this latter hypothesis, the objective of this thesis is to study the spatio-temporal modulations of motor cortex activity during movement preparation and execution. Three monkeys have been trained in an instructed delayed reach-to-grasp task. In each animal, a multielectrode Utah array was chronically implanted in the motor cortex to explore the dynamic modulations of neural activity during task performance. In a first study, we demonstrated that the modulations of neural activity related to distinct processes of motor preparation occur at different cortical locations. These locations are activated sequentially during motor preparation through alternating phases of stationary processing and dynamic propagation. In a second study, we analysed the neural interactions using a measure of spike count correlation (rsc) between pair of neurons. We reported 3 main results. Correlations are higher during movement preparation than during execution. They decrease with the distance between neurons. Finally, they are higher bewteen putative interneurons than bewteen putative pyramidal neurones. All these observations are discussed in relation to several models of the spatial organization the motor cortex.