An innovative two-stroke engine has been under development at Queen’s University. Traditional crankcase-scavenged two-stroke engines have laboured to meet emissions standards and achieve fuel economy comparable to four-stroke engines. The engine in question makes use of a modified Eaton-type supercharger to enable air-only scavenging, with this it utilizes direct fuel injection which occurs after the exhaust ports have closed, these two elements combine to eliminate the combustion of lubricating oil in the cylinder and short-circuiting of the fuel-air mixture into the exhaust. By having passive check valves in the cylinder head to regulate the inflow of scavenging air, and exhaust ports located near bottom centre this results in a top-down uniflow-scavenged configuration, as well as retaining a simplistic engine design. In the two-stroke cycle, using the intake charge to replace the combustion products with fresh air during scavenging is critical to engine performance. In this engine the scavenging charge is produced by a set of passive intake check valves, and because of this the scavenging timing is important. These valves are important because they govern the volume of combustion products that are forced out of the cylinder during scavenging, and hence the efficiency of combustion in the engine. To evaluate the engine design criteria, a validated computational fluid dynamic (CFD) model was used to offer insight into how the in-cylinder flow developed during scavenging. The CFD model of this engine was used to test different check-valve geometries to see how they affect the scavenging flow in the cylinder. The goal of this is to assist in entraining more of the combustion products which would result in more being exhausted from the cylinder. A more favourable design was found, and a design produced to be taken onto the next step of testing. / Thesis (Master, Mechanical and Materials Engineering) -- Queen's University, 2010-07-12 17:09:58.81

No description available.

Having a stroke at a younger age has been described as a complex experience that raises specific issues and related serice needs, mainly to do with child care, employment and social life. However, there has been little research into how younger people define what a stroke means for them personally and socially and how they live with it in the long term. This study aims to capture the experience of having had a stroke in people under fifty-five during the first year of their stroke. The purpose is to develop an understanding of the experience and to make this knowledge useful- for other people with this illness, for health care in general- and nursing in particular.

Bakgrund och syfte: Multidisciplinär hemrehabilitering för personer med milda till måttliga strokesymtom har visat sig vara en evidensbaserad intervention. Flera studier hade gjorts inom ämnet, men det saknades en tydlig beskrivning av åtgärderna och dess innehåll inom multidisciplinär hemrehabilitering. En sådan kunskap bedömdes vara viktig för att arbetsterapeuten skulle kunna arbeta utifrån arbetsterapeutiskt perspektiv. Syftet med denna studie var att sammanställa den kunskap som fanns inom multidisciplinär hemrehabilitering, avseende dess åtgärder, effekt och faktorer som påverkade rehabiliteringens effekt samt för- och nackdelar med den multidisciplinära hemrehabiliteringen. Metod: Litteraturstudie där både artiklar med kvalitativa och kvantitativa metoder inkluderades. Resultat: Åtgärder som utfördes inom multidisciplinär hemrehabilitering var bl.a. insiktsträning, kompensatoriska strategier, uppmuntran till att hitta egna problemlösningar och att anta uppmaningar på rätt nivå, uppgift- och kontextorienterade metoder, guidning, kommunikationsträning, information och rådgivning. Åtgärdernas effekt var bl.a. förbättrad ADL-förmåga och tillfredställelse hos klienten avseende vårdens kvalitet och de varierande träningsmiljöerna. Faktorer som kunde påverka rehabiliteringens effekt var bl.a. funktionsnedsättningens omfattning, samtidiga sjukdomar, klientens insikt om sin funktionsnedsättning, hemmiljön, delaktigheten vid planering av hemrehabiliteringsprogrammet, information från och till klienten och anhöriga, anhörigstöd och geografiska faktorer. Fördelar med multidisciplinär hemrehabilitering var förkortad vårdtid, kostnadseffektiv vårdform, garanti för kontinuiteten i vårdkedjan och nöjda klienter. Nackdelar med multidisciplinär hemrehabilitering var att den var tidskrävande och kunde ge extra börda och sämre livskvalitet hos anhöriga. Slutsats: Den multidisciplinära hemrehabiliteringen var en effektiv rehabiliteringsform för personer med stroke, men den krävde insatser riktade mot anhöriga för att inte riskera deras hälsa och livskvalitet. Flertalet av åtgärderna som utförs var typiskt arbetsterapeutiska, därför kunde det dras en slutsats att arbetsterapeuter utgjorde en viktig roll i den multidisciplinära hemrehabiliteringen.

Most stroke survivors recover some degree of lost function after an ischemic event. Recovery however, is negatively affected by comorbid conditions such as diabetes. Successful recovery is dependent on the ability of adjacent surviving cortical tissue and functionally related areas to take over functions lost by the stroke. Recently our lab has shown that diabetes interferes with the remapping of sensory function to peri-infarct areas after photothrombotic stroke. Given this result, it is crucial to understand how diabetes affects the structure of neurons following stroke, particularly at the level of dendritic spines, which receive the vast majority of excitatory synaptic inputs. Type I diabetes was pharmacologically induced in transgenic mice expressing yellow fluorescent protein (YFP) in a subset of cortical neurons 4 weeks prior to receiving unilateral photothrombotic stroke in the forelimb area of the primary somatosensory cortex (FLS1). Spine density measurements were made on the apical and basilar dendrites of layer-5 pyramidal neurons at 1 and 6 weeks after stroke. Our analysis indicated that diabetes was associated with fewer apical and basilar dendritic spines in the peri-infarct region 1 week after stroke. At 6 weeks of recovery, peri-infarct dendritic spine density in both control and diabetic animals returned to baseline levels. These changes were specific to the peri-infarct cortex, as spine density in distant cortical areas such as the forelimb sensorimotor region of the contralateral hemisphere, were not affected by stroke. In order to relate changes in spine density to the recovery of forepaw function, we re-analyzed data from a previous study that employed the forepaw adhesive-tape-removal test (Sweetnam et al 2012). This analysis revealed that diabetes significantly increased the latency of tape removal from the impaired forepaw (when normalized to the unaffected paw) at 1 but not 6 weeks of recovery. Collectively, these findings indicate that diabetes exacerbates forepaw impairments and basilar spine loss initially after stroke, but does not affect the ability of the brain to replace lost spines over weeks of recovery. / Graduate / 0317

No description available.

No description available.

The majority of people with stroke regard walking in their community as very important (Lord et al 2004). Walking in the community is limited by slow walking speeds and poor walking capacity (Lord et al 2004; Patterson et al 2007). Slow walking speeds and poor walking capacity are identified sequela in people with stroke (Hill et al 1997). By the end of rehabilitation approximately 80% of people with stroke achieve independent walking (Dean & Mackay 1992; Hill et al 1997). However, less than 10 percent are able to easily walk in their community (Hill et al 1997). Optimal motor learning requires task-specific practice (Carr & Shepherd 2003). Treadmills offer the opportunity for repetitive practice of complete gait cycles (Shepherd & Carr 1999), potentially providing greater intensity and longer duration walking practice than usual physiotherapy rehabilitation. Recently there has been some suggestion that high-intensity interventions may improve walking in people with stroke (Moseley et al 2005). Low levels of cardiorespiratory fitness in people with stroke have been shown to impact on walking, in particular walking capacity (Kelly et al 2003). Treadmills, commonly used to retrain cardiorespiratory fitness in the healthy population, have been used to implement high-intensity interventions, improving cardiorespiratory fitness in people with chronic stroke (Macko et al 2005). Therefore it is possible that exercise aimed at improving cardiorespiratory fitness may improve walking in people with stroke. The aim of these four studies was to investigate in those following stroke if walking on a treadmill at high-intensity during inpatient rehabilitation could improve walking capacity without compromising pattern and quality. The first study determined, in an Australian setting, the duration and intensity of usual physiotherapy rehabilitation. Study 2 compared walking pattern immediately following overground and treadmill walking practice at the same intensity. Study 3 examined the effect of treadmill walking at intensities high enough to influence cardiorespiratory fitness on walking pattern and quality. The final study, investigated the feasibility of implementing a high-intensity treadmill intervention in addition to usual physiotherapy rehabilitation in people following stroke able to walk undergoing inpatient rehabilitation. Intensity in all studies was calculated using heart rate reserve or the Karvonen method. Heart rate is a valid, accurate and stable indicator of exercise intensity due to its relatively linear relationship with oxygen consumption (ACSM 2006). For those people taking beta-blocker medication, the heart rate-lowering effect of this type of medication was accommodated. A target intensity of 40% heart rate reserve was used; as this is the minimum required improve cardiorespiratory fitness (ACSM 2006). Walking pattern and quality were measured in Studies 2-4. Walking pattern was measured by linear kinematics using GAITRite (CIR Systems, Clifton, NJ, USA) and angular kinematics using a 2-dimensional webcam application. Walking quality was determined by observation of the webcam footage and scored using the Rivermead Visual Gait Assessment, Wisconsin Gait Scale and a vertical visual analogue scale by blinded assessor. The first study found that people with stroke spent an average of 21 (SD 11) minutes participating in standing and walking activities that are associated with reaching the target intensity during physiotherapy rehabilitation. Those who could walk spent longer in these activities (25 minutes, SD 12) compared to those would couldn’t walk (17 minutes, SD 9). However, the intensity of these activities was low; walkers reached a maximum of 30% heart rate reserve and non-walkers reached 35% heart rate reserve. Using the treadmill as a mode of task-specific physiotherapy rehabilitation, the second study in this thesis found that walking pattern was similar following 10 minutes of treadmill and overground walking practice at the same intensity. The third study found that during walking on the treadmill at intensities high enough to influence cardiorespiratory fitness (up to 60% heart rate reserve), many of the linear and angular kinematic parameters moved closer to a more normal pattern and walking quality was not compromised. The final study in this thesis, a randomised controlled trial, found that a 6-week high-intensity treadmill walking intervention was feasible in people with stroke able to walk who were undergoing rehabilitation. Participants attended 89% of the treadmill sessions, reaching an average duration of more than 20 minutes and an intensity of 40% heart rate reserve after two weeks. The intervention also appeared effective with significant improvements in walking speed and capacity following the treadmill walking intervention. Improvements in walking speed were maintained at 3 months. In summary, these studies found that usual physiotherapy in people with stroke was of low intensity. In addition, it was found that treadmill walking was safe and feasible as a means of increasing the intensity of physiotherapy rehabilitation, without compromising walking quality and pattern. Therefore, it may be possible to improve walking in people with stroke using high-intensity treadmill walking.

The majority of people with stroke regard walking in their community as very important (Lord et al 2004). Walking in the community is limited by slow walking speeds and poor walking capacity (Lord et al 2004; Patterson et al 2007). Slow walking speeds and poor walking capacity are identified sequela in people with stroke (Hill et al 1997). By the end of rehabilitation approximately 80% of people with stroke achieve independent walking (Dean & Mackay 1992; Hill et al 1997). However, less than 10 percent are able to easily walk in their community (Hill et al 1997). Optimal motor learning requires task-specific practice (Carr & Shepherd 2003). Treadmills offer the opportunity for repetitive practice of complete gait cycles (Shepherd & Carr 1999), potentially providing greater intensity and longer duration walking practice than usual physiotherapy rehabilitation. Recently there has been some suggestion that high-intensity interventions may improve walking in people with stroke (Moseley et al 2005). Low levels of cardiorespiratory fitness in people with stroke have been shown to impact on walking, in particular walking capacity (Kelly et al 2003). Treadmills, commonly used to retrain cardiorespiratory fitness in the healthy population, have been used to implement high-intensity interventions, improving cardiorespiratory fitness in people with chronic stroke (Macko et al 2005). Therefore it is possible that exercise aimed at improving cardiorespiratory fitness may improve walking in people with stroke. The aim of these four studies was to investigate in those following stroke if walking on a treadmill at high-intensity during inpatient rehabilitation could improve walking capacity without compromising pattern and quality. The first study determined, in an Australian setting, the duration and intensity of usual physiotherapy rehabilitation. Study 2 compared walking pattern immediately following overground and treadmill walking practice at the same intensity. Study 3 examined the effect of treadmill walking at intensities high enough to influence cardiorespiratory fitness on walking pattern and quality. The final study, investigated the feasibility of implementing a high-intensity treadmill intervention in addition to usual physiotherapy rehabilitation in people following stroke able to walk undergoing inpatient rehabilitation. Intensity in all studies was calculated using heart rate reserve or the Karvonen method. Heart rate is a valid, accurate and stable indicator of exercise intensity due to its relatively linear relationship with oxygen consumption (ACSM 2006). For those people taking beta-blocker medication, the heart rate-lowering effect of this type of medication was accommodated. A target intensity of 40% heart rate reserve was used; as this is the minimum required improve cardiorespiratory fitness (ACSM 2006). Walking pattern and quality were measured in Studies 2-4. Walking pattern was measured by linear kinematics using GAITRite (CIR Systems, Clifton, NJ, USA) and angular kinematics using a 2-dimensional webcam application. Walking quality was determined by observation of the webcam footage and scored using the Rivermead Visual Gait Assessment, Wisconsin Gait Scale and a vertical visual analogue scale by blinded assessor. The first study found that people with stroke spent an average of 21 (SD 11) minutes participating in standing and walking activities that are associated with reaching the target intensity during physiotherapy rehabilitation. Those who could walk spent longer in these activities (25 minutes, SD 12) compared to those would couldn’t walk (17 minutes, SD 9). However, the intensity of these activities was low; walkers reached a maximum of 30% heart rate reserve and non-walkers reached 35% heart rate reserve. Using the treadmill as a mode of task-specific physiotherapy rehabilitation, the second study in this thesis found that walking pattern was similar following 10 minutes of treadmill and overground walking practice at the same intensity. The third study found that during walking on the treadmill at intensities high enough to influence cardiorespiratory fitness (up to 60% heart rate reserve), many of the linear and angular kinematic parameters moved closer to a more normal pattern and walking quality was not compromised. The final study in this thesis, a randomised controlled trial, found that a 6-week high-intensity treadmill walking intervention was feasible in people with stroke able to walk who were undergoing rehabilitation. Participants attended 89% of the treadmill sessions, reaching an average duration of more than 20 minutes and an intensity of 40% heart rate reserve after two weeks. The intervention also appeared effective with significant improvements in walking speed and capacity following the treadmill walking intervention. Improvements in walking speed were maintained at 3 months. In summary, these studies found that usual physiotherapy in people with stroke was of low intensity. In addition, it was found that treadmill walking was safe and feasible as a means of increasing the intensity of physiotherapy rehabilitation, without compromising walking quality and pattern. Therefore, it may be possible to improve walking in people with stroke using high-intensity treadmill walking.

The majority of people with stroke regard walking in their community as very important (Lord et al 2004). Walking in the community is limited by slow walking speeds and poor walking capacity (Lord et al 2004; Patterson et al 2007). Slow walking speeds and poor walking capacity are identified sequela in people with stroke (Hill et al 1997). By the end of rehabilitation approximately 80% of people with stroke achieve independent walking (Dean & Mackay 1992; Hill et al 1997). However, less than 10 percent are able to easily walk in their community (Hill et al 1997). Optimal motor learning requires task-specific practice (Carr & Shepherd 2003). Treadmills offer the opportunity for repetitive practice of complete gait cycles (Shepherd & Carr 1999), potentially providing greater intensity and longer duration walking practice than usual physiotherapy rehabilitation. Recently there has been some suggestion that high-intensity interventions may improve walking in people with stroke (Moseley et al 2005). Low levels of cardiorespiratory fitness in people with stroke have been shown to impact on walking, in particular walking capacity (Kelly et al 2003). Treadmills, commonly used to retrain cardiorespiratory fitness in the healthy population, have been used to implement high-intensity interventions, improving cardiorespiratory fitness in people with chronic stroke (Macko et al 2005). Therefore it is possible that exercise aimed at improving cardiorespiratory fitness may improve walking in people with stroke. The aim of these four studies was to investigate in those following stroke if walking on a treadmill at high-intensity during inpatient rehabilitation could improve walking capacity without compromising pattern and quality. The first study determined, in an Australian setting, the duration and intensity of usual physiotherapy rehabilitation. Study 2 compared walking pattern immediately following overground and treadmill walking practice at the same intensity. Study 3 examined the effect of treadmill walking at intensities high enough to influence cardiorespiratory fitness on walking pattern and quality. The final study, investigated the feasibility of implementing a high-intensity treadmill intervention in addition to usual physiotherapy rehabilitation in people following stroke able to walk undergoing inpatient rehabilitation. Intensity in all studies was calculated using heart rate reserve or the Karvonen method. Heart rate is a valid, accurate and stable indicator of exercise intensity due to its relatively linear relationship with oxygen consumption (ACSM 2006). For those people taking beta-blocker medication, the heart rate-lowering effect of this type of medication was accommodated. A target intensity of 40% heart rate reserve was used; as this is the minimum required improve cardiorespiratory fitness (ACSM 2006). Walking pattern and quality were measured in Studies 2-4. Walking pattern was measured by linear kinematics using GAITRite (CIR Systems, Clifton, NJ, USA) and angular kinematics using a 2-dimensional webcam application. Walking quality was determined by observation of the webcam footage and scored using the Rivermead Visual Gait Assessment, Wisconsin Gait Scale and a vertical visual analogue scale by blinded assessor. The first study found that people with stroke spent an average of 21 (SD 11) minutes participating in standing and walking activities that are associated with reaching the target intensity during physiotherapy rehabilitation. Those who could walk spent longer in these activities (25 minutes, SD 12) compared to those would couldn’t walk (17 minutes, SD 9). However, the intensity of these activities was low; walkers reached a maximum of 30% heart rate reserve and non-walkers reached 35% heart rate reserve. Using the treadmill as a mode of task-specific physiotherapy rehabilitation, the second study in this thesis found that walking pattern was similar following 10 minutes of treadmill and overground walking practice at the same intensity. The third study found that during walking on the treadmill at intensities high enough to influence cardiorespiratory fitness (up to 60% heart rate reserve), many of the linear and angular kinematic parameters moved closer to a more normal pattern and walking quality was not compromised. The final study in this thesis, a randomised controlled trial, found that a 6-week high-intensity treadmill walking intervention was feasible in people with stroke able to walk who were undergoing rehabilitation. Participants attended 89% of the treadmill sessions, reaching an average duration of more than 20 minutes and an intensity of 40% heart rate reserve after two weeks. The intervention also appeared effective with significant improvements in walking speed and capacity following the treadmill walking intervention. Improvements in walking speed were maintained at 3 months. In summary, these studies found that usual physiotherapy in people with stroke was of low intensity. In addition, it was found that treadmill walking was safe and feasible as a means of increasing the intensity of physiotherapy rehabilitation, without compromising walking quality and pattern. Therefore, it may be possible to improve walking in people with stroke using high-intensity treadmill walking.