Stroke is an age-related illness with significant individual and societal impacts. The long term impacts associated with many strokes can be mitigated with timely rehabilitation. Therapy robots have been introduced to these programs in an effort to reduce the economic burden to society and to improve the level of care provided to stroke survivors. The purpose of this thesis is to develop a teaching mode for an upper limb therapy robot. The system will allow physiotherapists to interact with the therapy robot without the need for any specialized industrial training. At the same, the system will reduce the data associated with patient movements to reduce requirements for robot safety and motion systems. The proposed system was successfully confirmed using a laboratory scale industrial robot and a standalone motion control system consisting of commercially available AC servo motors and a motion controller with both generated and recorded paths.

The development of a numerical model of a two-stroke engine is undertaken to study the scavenging characteristics of the engine. The engine design is unique in its use of 16 passive intake valves in the cylinder head which, along with the exhaust ports located at bottom centre (BC), give the engine a top-down uniflow-scavenged configuration. Each valve constitutes a small stainless steel platelet within a cavity in the cylinder head which reacts to the pressure difference across the cylinder head. The principle focus of this study is the transient simulation of the scavenging flow using dynamic meshing to model the piston motion and the response of the passive intake valves to the scavenging flow for varied engine speed and peak pressure. A flowbench study of the steady flow through the cylinder head into a duct is incorporated as a step in the development of the transient numerical model. Validation of the numerical predictions is undertaken by comparing results from an experimental flowbench for the steady case and using a cold-flow scavenging rig for the transient simulations. Both the steady flow through the cylinder head and the unsteady flow within the cylinder indicate the presence of a recirculation region on the cylinder axis. As a result, short-circuiting of scavenging gas becomes considerable and leads to scavenging characteristics comparable to Hopkinson’s perfect mixing one-dimensional scavenging model. / Thesis (Master, Mechanical and Materials Engineering) -- Queen's University, 2008-09-26 18:38:53.375

Background: Though numerous studies have compared overground and treadmill walking there still exists a significant debate about whether the two modes of walking are equivalent. The present study provides a comprehensive evaluation of overground and treadmill walking at matched speeds and increasing treadmill speeds. Walking performance was compared in healthy adults, in people with stroke and between the groups. This is important to know because any differences may have implications for gait training in both groups. Methods: Ten healthy adults (50-73 years) and ten subjects with stroke (54-80 years) walked at their self-selected speed overground which was matched on a treadmill. Temporal parameters, angular kinematics and vertical ground reaction forces were recorded during walking once subjects were in steady state as determined from their heart rate and oxygen uptake, both of which were also recorded. Belt speed was then increased 10% and 20% above matched speed and steady state recordings obtained. Speed related adjustments were also evaluated and compared between the two groups of subjects. Results: For healthy adults, step, stride, and joint angular kinematics were similar for both modes of walking. Small reductions in double support time and decreased push-off force were evident on the treadmill. For subjects with stroke, step, stride, and stance times were longer when walking overground but the degree of symmetry was comparable for both surfaces. Kinematic data revealed interlimb asymmetry was more pronounced for all lower limb joint excursions during overground walking and vertical forces were higher. In comparison to healthy adults, stroke subjects walked with lower cadence, shorter strides, lower stance time, and smaller lower limb joint excursions than their healthy counterparts. When compared with overground walking the metabolic requirements of treadmill walking for healthy adults and subjects with stroke however were about higher by 23% and 15% respectively. All temporal-distance parameters, hip joint excursion, F1 and F2 forces and metabolic costs showed main effects of speed. An interaction between speed and group indicated that oxygen consumption increased at a greater rate in stroke than healthy subjects. Conclusions: The findings suggest that, although overground and treadmill gait patterns are similar for each group of subjects, people with stroke adopt a more symmetrical kinematic walking pattern on the treadmill that is maintained at faster belt speeds. Although there are differences in gait patterns between healthy and stroke subjects, both groups respond to the challenge of increased walking speed in the same way. One important difference is the abnormal elevation of energy demands associated with treadmill walking at faster speeds in stroke. Clinically, this warrants consideration as it may lead to premature fatigue and undesirable cardiorespiratory challenge in this group of individuals. / Thesis (Ph.D, Rehabilitation Science) -- Queen's University, 2009-08-27 06:41:19.999

No description available.

The contribution of single complement system (CS) activation pathways to cerebral IR injury has not yet been adequately studied after ischemic stroke and reperfusion. It remains unclear whether a specific activation pathway (alternative, classical or lectin), single complement factors within the CS, or anaphylatoxins are responsible for increased cerebral IR injury after ischemic stroke and reperfusion. Also poorly understood is the relationship between these elements (activation pathways, CS factors and anaphylatoxins) and neutrophil mediated cerebral IR injury. The objective of this dissertation was to test the hypothesis that mannose binding lectin (MBL) deficiency during cerebral ischemia and reperfusion will result in a significant reduction of systemic neutrophil activation and cerebral injury after ischemic stroke and reperfusion via decreased CS activation and subsequent decreased anaphylatoxin production. Using the intraluminal filament method, mice with targeted mutations to MBL A/C genes (MBL-/- ) or the C57Bl/6 strain (MBL +/+ ) were subjected to 60 minutes of cerebral ischemia and either 15 minutes or 24 hours of reperfusion. After reperfusion (15 min and 24 hour) blood was removed to assess systemic neutrophil CD11b expression via flow cytometry. After 24 hours of reperfusion, the brain was removed to assess cerebral injury. CS activation after ischemic stroke and reperfusion was assessed via immunofluorescent C3 staining and RT-rtPCR methods. Our primary findings are, after ischemic stroke and reperfusion: (1) hepatic MBLA gene expression is significantly increased, (2) systemic neutrophils significantly express CD11b, (3) MBL deficiency significantly decreased cerebral infarct volume in the striatum but not in the cortex or total hemisphere, and (4) systemic neutrophil activation is independent of MBL deficiency. This study is the first to examine the contribution of MBL-initiated lectin pathway activation to cerebral IR injury after ischemic stroke and reperfusion. These findings suggest that MBL deficiency does not significantly reduce neutrophil activation or protect brain tissue after ischemic stoke and reperfusion. A complete understanding of reperfusion events after ischemic stroke is necessary for successful development of future stroke therapies to prevent cerebral IR injury. In this way, the acquisition of knowledge from the bench serves the stroke population cared for by nurses at the bedside.

Problem: Many individuals with chronic illnesses such as stroke and ongoing activity limitations report self-perceived health related quality of life (HRQL) that is similar to that of healthy individuals. This phenomenon is termed response shift (RS). RS describes how people change: internal standards in assessing HRQL (recalibration), values (reprioritization), or how they define HRQL (reconceptualization), after an event such as stroke. Changes in HRQL post stroke may be inaccurate if RS is not taken into account. Increased knowledge of RS may affect the way in which HRQL measures are used, both clinically and in research. The overall objective was to assess RS in construct specific HRQL models post stroke: physical function, mental health, and participation. Methods: Data were analysed from the longitudinal study “Understanding Quality of Life Post-Stroke: A Study of Individuals and their Caregivers”. Six-hundred and seventy- eight persons with stroke at 1, 3, 6, and 12 months post stroke participated. Generic and stroke specific HRQL measures were collected. Descriptive analysis was completed with SAS, and identification of RS utilized structural equation modeling with LISREL. Results: Mean age of participants was 67 years (SD 14.8), and 45% were female. RS was identified in mental health using a framework which was developed for identifying RS statistically with multiple time points. RS was also identified in physical function where it had not been expected, possibly due to the self perceived nature of the response options. The effect size of change in physical function was affected by the presence of RS. The timing of RS in mental health and physical function was primarily around the 12 month time period, and predominantly recalibration RS. RS was also identified in participation. Conclusions: The framework that was developed was useful in identifying RS and incorporated important issues such as multiple testing and validation of the model. The presence of RS affects measurement of HRQL constructs post stroke; recalibration RS can be measured clinically with specific methods to account for RS. RS should also be measured in research studies to ensure accurate measurement of change. Future research should evaluate additional models in stroke and other populations.

Glutamate is the primary excitatory neurotransmitter in the central nervous system. Extracellular glutamate concentrations are tightly regulated to avoid over-stimulation of glutamate receptors, which leads to a cascade of deleterious processes collectively known as excitotoxicity. Excitotoxicity is common to several neurodegenerative disorders and CNS injuries, including stroke and Alzheimer’s disease (AD). The projects described in this thesis were designed to uncover novel protective pathways in excitotoxic neurodegeneration. Excessive activation of the DNA repair enzyme, poly(ADP-ribose) polymerase-1 (PARP-1), is a convergence point for neuron death signaling in excitotoxic pathways. In AD, the peptide amyloid-β1-42 (Aβ1-42) is aberrantly produced, leading to excitotoxic neuron death in vitro. To investigate links between Aβ1-42 and PARP, we treated cultured cortical neurons with Aβ1-42 and determined whether PARP-1 contributes to neuron death. Increased neuron death was observed after Aβ1-42 exposure. A non-selective PARP-1/2 inhibitor significantly reduced Aβ1-42-induced death while elimination of PARP-1 alone was not neuroprotective. This suggests that PARP-2 or combined effects of PARP-1 and PARP-2 are required for Aβ1-42-induced neuron death. A hallmark of PARP over-activation is depletion of intracellular NAD+ and ATP levels, yet nearly all studies examining adenine nucleotide levels use separate biochemical samples to measure nucleotides individually. We developed two HPLC methods for simultaneous separation of NAD+, ATP, ADP and AMP. We determined that PARP-1 activation in astrocytes leads to near complete NAD+ depletion, followed by partial loss of ATP pools and total adenine nucleotide pools. Finally, we hypothesized that conjugated linoleic acid (CLA), a naturally occurring polyunsaturated fatty acid, is capable of enhancing neuron survival after an excitotoxic insult. Cultured cortical neurons were exposed to glutamate in the presence and absence of CLA. CLA levels likely achievable in human plasma and brain tissue during dietary supplementation regimens, protected neurons against glutamate excitotoxicity when given during or up to five hours after glutamate exposure. Several markers of mitochondrial damage and intrinsic apoptosis were examined. CLA stabilized mitochondrial membrane potential and permeability, shedding light on the mechanism of CLA neuroprotection. Overall, our research suggests a role for PARP in Aβ1-42 toxicity and identifies a novel role for CLA in neuroprotection following excitotoxicity.

Canadians are worried about the future of the health care system, and provincial governments are questioning the ability of the existing system to support Canadians health care needs in the 21st Century(Industry Canada, 2011). Health care providers and system administrators are both driving and experiencing a paradigm shift; moving away from paternalism and toward an egalitarian approach. In order to practice patient centredness, health care providers must prioritize patient needs; provide information regarding treatments while taking patient preferences into account (Romanow, 2002). While there is a growing body of literature regarding patient centredness, there is scant information from the patient perspective. If the most effective and acceptable health services are those that realize the expectations of the users, this is an important area of study. Using phenomenological research methods and the theory of planned behaviour as a theoretical framework, the purpose of the study was to explore the influence of beliefs, attitudes and experiences on behaviour from the perspective of patients in primary health care or stroke rehabilitation. A second purpose was to explore the degree to which beliefs, attitudes and behaviour were similar between clinical contexts. The theory of planned behaviour was unsuitable for understanding peoples’ beliefs, attitudes and behaviour about being a patient. Being a patient was not a single, observable behaviour, but rather a set of contextually dependent strategies patients’ directed at a particular goal. The goal for each participant group was different; rehabilitation patients focused on the specific goal of recovery and discharge, while PHC patients focused on a broader goal of accessing and receiving best health care possible. These goals were reflected in their respective approaches to accessing health care services, an experience they described as socially oriented, governed and reinforced. Although patients described themselves as actively engaged, they did not approach each interaction with health care with a set of behavioural beliefs about being a patient. During the course of their participation, patients identified, developed and adopted strategies to assist in achieving the target; and evaluated those strategies more positively.

Covert stroke (CS) comprises lesions in the brain often associated by risk factors such as a diet high in fat, salt, cholesterol and sugar (HFSCS). Developing a rodent model for CS incorporating these characteristics is useful for developing and testing interventions. The purpose of this thesis was to determine if magnetic resonance (MR) can detect brain abnormalities to confirm this model will have the desired anatomical effects. Ex vivo MR showed brain abnormalities for rats with the induced lesions and fed the HFSCS diet. Spectra acquired on the fixed livers had an average percent area under the fat peak relative to the water peak of (20±4)% for HFSCS and (2±2)% for control. In vivo MR images had significant differences between surgeries to induce the lesions (p=0.04). These results show that applying MR identified abnormalities in the rat model and therefore is important in the development of this CS rodent model.

This thesis describes the development of a MEMS repulsive actuator capable of producing a large out-of-plane force. Existing MEMS repulsive actuators are low out-of-plane force actuators that are unable to support or lift a mass of 1 mg. A high force MEMS repulsive actuator was developed to overcome this limitation. The design was optimized employing parameters of the actuator’s fingers to increase the out-of-plane force. A design was developed based on the analytical results derived from extending the mathematical model of an existing actuator. A commercial manufacturing process, PolyMUMPs, was used to fabricate a prototype which was tested to validate the analytical and computational results. The prototype achieved an out-of-plane displacement of 15 µm and a 0.2° angular rotation. The resonance frequency was 120 Hz, and the rise and fall times were measured as 14.5 ms and 3625 ms (3.6 sec), respectively. The estimated out-of-plane force is 40 µN.