title: Development of Antibacterial Efficacy Testing Method for TiO2 Coated Paper in the Presence of Light

contributor:
Pelton, Robert H.
Chemical Engineering

subject: antibacterial efficacy, testing method, TiO2 coated paper, light, photocatalytic, UV illumination

abstract:
 Photocatalytic TiO2 coated paper was prepared as antibacterial paper to investigate bactericidal activity of TiO2 in the presence of UV light. When TiO2 exposed to UV light, it produced hydroxyl radicals which were strong oxidative groups and could damage the cell wall causing death of bacteria. The goal of this work was to develop a promising method for microbiological examination of antibacterial paper and to test the disinfection properties of photocatalytic TiO2 coated paper after UV illumination.

 Three different methods were modified to test antibacterial effect of TiO2 coated paper. The disk diffusion method, the washing method, and the membrane filter method. It was found that disk diffusion technique would not work because of insolubility of TiO2 in water but it could be used for any other antibacterial paper that consisted water soluble agent. The results from membrane filter method agreed with those of washing method showing the reduction of E.coli colonies for TiO2 coated paper after exposure to UV, comparing to blank paper.

 With use of washing method, it was shown that by changing some functions such as: increasing TiO2 content on the paper, increasing UV irradiation time or UV intensity, survival ratio of the bacteria decreased.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Regulation of Nitrate Assimilation in Maize and Barley

title: Regulation of Nitrate Assimilation

contributor:
Oaks, Ann
Biology

subject:
maize
barley
nitrate assimilation

abstract: To determine the limiting factors in nitrate assimilation in maize and barley, the effects of nitrate on 1) steady state levels of nitrate reductase activity (NRA) and nitrate reductase protein (NRP); 2) the uptake, translocation and accumulation of nitrate in the shoots of the seedling plant were examined. Seedlings were grown on Kimpack paper containing l, 5 or 20mM KN0₃ for 7 days at 20°c (barley) or 28°C (maize). At lmM KN0₃ the rate of 3 nitrate uptake and the levels of NRA and NRP were higher in maize than in barley. In contrast., at 5 and 20mlv1 KNo₃, the rate of uptake, the accumulation of nitrate and the NRA were higher in barley than in maize. The results suggest that the synthesis of NR is induced by lower levels of nitrate in maize relative to barley. In addition, nitrate-nitrogen appears to be more efficiently converted to proteins, other than NR, in maize than in barley. At very low levels of nitrate an inactive NR protein was present. in maize. To characterize the inactive NR, maize plants were grown under conditions where high levels of NRA were detected (vermiculite:sand, l:lw/w, containing 10mM KN0₃) and under conditions where NR was present primarily in the inactive form (Kimpack paper:washed sand). Nitrate reductase was purified from primary leaves using Blue Sepharose affinity chromatography. The column was washed with NADH and KN0₃ in each case. The peaks of NR were 3 detected using Dot-immunoblotting, with an antibody prepared against maize leaf NR and by assessing the NRA. Active and inactive NR forms were found both at the NADH-and the KN0₃-wash. In the NADH-wash, the inactive NR as compared to the active form, has very low NADH (complete), FMNH₂, MV and BPB (reductase) activities. Significant levels of cyt-c and FeCN (dehydrogenase) partial activities were detected. Similarly, the inactive NR in the KN0-wash, had 3no NADH (complete), FMNH2 , MV and BPB (reductase) activities. Very low levels of cyt-c and FeCN (dehydrogenase) NR partial activities were detected, compared to the respective activities of the active enzyme in the KNO₃ wash.

abstract: Thesis

abstract: Master of Science (MSc)


title: The Effects of Exercise Intensity and Duration on Excess Post-Exercise Oxygen Consumption

contributor:
Sale, D. G.
Human Biodynamics

subject:
exercise intensity
oxygen
post-exercise

abstract:
The effects of exercise intensity and duration on excess post-exercise oxygen consumption (EPOC) were examined. Eight males exercised in a thermoneutral environment at 60% of maximal aerobic power (V0₂ₘₐₓ) for 30 min and performed the same total work at 80% and 40% V0₂ₘₐₓ by varying exercise durations. In addition, 2 work bouts were performed at 60% VO₂ₘₐₓ for 90 and 60 min. A standardized meal was consumed 2 h post-exercise. Oxygen consumption (V0₂), respiratory exchange ratio (RER), rectal temperature (Tc) and heart rate
(HR) were monitored on a control day and before, during and for 3 h following exercise. VO₂ was equivalent to control day values within 30 min post-exercise on each of the 5 d and no consistent relation between exercise condition and duration of EPOC was observed. When total post-exercise VO₂ was expressed relative to control values, differences were greatest during the first 30 min post-exercise. Total net caloric expenditure was small (32. 5-57.9 kcal) in all cases. RER tended to remain equivalent to control levels post-exercise, with intermittent elevations. Significant elevations in Tc were obtained until 60 to 150 min post-exercise. No significant exercise-related effects were noted for dietary induced thermogenesis or the cumulative effect of the 5 exercise bouts on resting metabolic rate. Although exercise over a wide range of intensities and durations resulted in a significant EPOC, in all cases it was of short duration and the total 3 h energy expenditure was small. Neither duration nor magnitude of EPOC was associated with post-exercise RER or Tc.

abstract: Thesis

abstract: Master of Science (MSc)


title: Alloxan Diabetes in the Catfish

contributor:
Nace, Paul F
Biology

subject: catfish, diabetes

abstract:
Thesis
Master of Science (MSc)


title: Gender Differences in Strength and Muscle Fiber Characteristics

contributor:
MacDougall, J. D.
Human Biodynamics

subject:
gender
strength
muscle fiber

abstract: A gender difference in absolute muscle strength is well documented. The extent to which quantitative (fiber area and number) and qualitative (specific tension) differences in muscle contribute to this is not well understood. The purpose of this study was to examine a variety of muscle characteristics in the biceps brachii and vastus lateralis in a sample of males (n=8) and females (n=8) with a wide range of training histories. Measurements included motor unit number, size and activation, and voluntary strength of the elbow flexors and knee extensors. Fiber characteristics were determined from needle biopsies and muscle areas by computerized tomographical scanning. Females were approximately 52% and 66% as strong as the males in the upper and lower body respectively. A significant (p ≤ .05) correlation was found between strength and muscle cross-sectional area. Females had 45, 41, 30 and 25% smaller muscle cross-sectional areas for the biceps brachii, total elbow flexors, vastus lateralis and total knee extensors respectively (p ≤ .01). No significant gender difference was found in the strength to cross-sectional area ratio for elbow flexion and knee extension. Males had significantly larger type I fiber areas (4597 vs. 3483 um² ) and mean fiber areas (6632 vs. 3963 um² ) than females in biceps brachii (p ≤ .05) and significantly larger type II fiber areas (7700 vs. 4040 um²) and mean fiber areas (7070 vs. 4290 um²) in the vastus lateralis (p ≤ .05). The difference in type II fiber area in the biceps brachii was not statistically significant despite the fact that these fibers were almost twice as large in the males as in the females (8207 vs. 4306 um²). No significant gender difference was found in biceps fiber number (180,620 vs. 156,872) or muscle area to fiber area ratio in the vastus lateralis (451,468 vs. 465,007). No significant gender differences were found in any of the motor unit characteristics. The results indicate that the primary determinant of the greater muscle strength of males is their larger mean fiber areas which results in greater muscle cross-sectional areas.

abstract: Thesis

abstract: Master of Science (MSc)


title: The Effect of Endurance Training on Muscle Strength and Power

subject: endurance training, muscle strength, power, cycle ergometer, aerobic

abstract: In order to investigate possible negative effects of endurance training on muscle strength and power, 10 healthy young men underwent 10 weeks of endurance training. Subjects trained unilaterally on a cycle ergometer so that their opposite leg served as a control. Training consisted of 30 min per day for 3 days per week and progressed to 60 min per day for 5 days per week by the seventh week of training. This volume of endurance training exceeds the upper limits of that normally performed by athletes who compete in power sports. The exercise intensity was initially ~75% of pre-training maximum power output and was increased over time to maintain a training heart rate of 140-160 beats per minute. Endurance, strength, and power variables were assessed in each leg before and after the training period. Measurements included electrically stimulated twitch characteristics of the quadriceps, single-leg V̇O2peak and lactate threshold (Tlac), single-leg take-off vertical jump power indices from a force platform, and maximal leg press strength at a low-(60°/s) and high-velocity (300°/s). Needle biopsies were taken from the quadriceps femoris before and after the training period, and analyzed for fibre-type proportions, fibre area, oxidative enzyme activity and capillary density. Post-training, subjects increased leg V̇O2peak (7%) and Tlac in the trained leg. Leg press strength was unaffected by training. Vertical jump power was not impaired nor were evoked twitches. Following training, there was a decrease in % type IIb and an increase in % type IIa fibres (p<0.05). There were no significant changes in fibre area. Percent fibre area increased for type I and IIa and decreased for type IIb fibres in the trained leg (p<0.05). These data indicate that a 10-week endurance-training program increases aerobic power but does not impair muscle strength or power.

abstract: Thesis

abstract: Master of Science (MSc)


title: Neocortical Long-Term Depression and Depotentiation in the Adult Freely Moving Rat

contributor:
Racine, Ronald
Psychology

subject: neocortical depression depotentiation rat

abstract: Information is believed to be stored in the brain by constructing new neural circuits, and these circuits are shaped by changes in the strength of the synaptic connections between the neurons making up the circuit. According to most theories of memory, new circuits can be formed by either increasing or decreasing the strength of synaptic connections. Bidirectional modifications in synaptic efficacy are also central components in recent computer simulations of learning and memory. While long-term potentiation (LTP) has been the focus of extensive research into the mechanisms underlying information storage in the mammalian brain, long-term depression (LTD) and depotentiation, its depressive counterparts, have not. Furthermore, most of the LTD research has involved the use of anaesthetized animals and in vitro slice preparations, making it more difficult to determine the role of this synaptic phenomenon in learning and memory in the intact behaving animal. This thesis provides the first detailed examination of: 1) the induction and decay of both LTD and depotentiation in the neocortex of the awake, freely moving animal; 2) the effects of N-methyl D-Aspartate receptor (NMDAR) blockade on the induction of LTD, LTP, and depotentiation (NMDA receptor activation is known to play a major role in most forms of LTP); and 3) the interactions between these synaptic phenomena. LTD was expressed as a significant reduction in the amplitude of both short and long-latency field potential components. Depotentiation was expressed as a long lasting decrease in the amplitude of a previously enhanced late component. LTD was found to be greater in magnitude and longer lasting when the conditioning stimulation was repeated. However, unlike LTP induction, the conditioning stimulation was equally effective whether spaced over hours or days. NMDA receptor antagonism blocked LTP induction and instead produced a depression effect similar to LTD. Unlike LTP, LTD and depotentiation were found to be NMDAR-independent in the neocortex of the freely moving rat. LTP and LTD are both reversible phenomena and LTD-inducing stimulation can modulate the effects of LTP-inducing stimulation. LTD-inducing stimulation, when delivered following to LTP-inducing stimulation, attenuates the induction rate for potentiation. LTD and depotentiation may play important roles in the ongoing experience-induced modification of neuronal connectivity. Furthermore, these results are consistent with the hypothesis that potentiation and depression reflect the physiological instantiation of a bidirectional learning rule.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: The Relationship Between Extracellular Potassium Concentrations and Muscle Membrane Excitability Following a Sustained Submaximal Isometric Quadriceps Contraction

contributor:
Hicks, A.
Human Biodynamics

subject:
extracellular
potassium
muscle membrane
quadriceps contraction

abstract: The purpose of this study was to relate femoral venous plasma potassium concentrations ([K⁺]) following a fatiguing submaximal isometric quadriceps contraction, to the excitability of the muscle cell membrane as assessed by the compound muscle action potential (M-Wave) . Ten healthy male volunteers (22. 0 ± . 5 yrs) performed a unilateral 3 minute (min) sustained isometric quadriceps contraction at 30% of their maximum voluntary contraction (MVC) . M-Waves, peak evoked twitch torque, plasma lactate concentration ([La⁻]), and plasma potassium concentration ([K⁺]) were measured before, and at predetermined times over the course of a 15 min recovery period following the fatigue paradigm. Immediately post-exercise, twitch torque decreased to 58% of baseline, femoral venous [La⁻] had risen to 10 ± 0.8 mmol/1, and [K⁺] was significantly increased from 4.0 ± 0.1 mmol/1 to 5.9 ± 0.2 mmol/1. M-Wave amplitude illustrated a trend for potentiation increasing 9.5%-from 13.9 ± 2.4 mV pre-exercise, to 15.3 ± 2.8 mV at 1 min 20 seconds post-exercise. M-Wave area exhibited a similar trend from baseline, but values showed no statistical significance during this time. These results suggest that in spite of increased extracellular [K⁺] following this type of fatiguing exercise, muscle membrane excitability is maintained, which is probably due to the electrogenic nature of the highly active Na⁺ /K⁺ pump. This study was supported by the Natural Sciences and Engineering Research Council of Canada.

abstract: Thesis

abstract: Master of Science (MSc)


title: SITUATIONAL AWARENESS FOR CONSTRUCTION SAFETY RISKS MANAGEMENT

contributor:
Razavi, Saiedeh
Civil Engineering

abstract:
The high number of construction injuries and fatalities resulted from struck-by-equipment hazards is one of the major challenges faced by the construction industry. Improved situational awareness assists workers to recognize hazardous situations, make decisions, and take actions in a timely manner to prevent hazards. Advanced technologies have been widely recognized as holding great promise to enable innovative applications in construction to improve situational awareness and to prevent struck-by-equipment hazards. However, existing solutions for detecting struck-by-equipment hazards generate frequent false alarms which interrupt construction and reduce site mobility and productivity. Also, there has been a need for an integrated method that can concurrently monitor and analyze the struck-by-equipment risk at both individual and system levels to enable proactive hazard prevention.
This research addresses the above-mentioned challenges by introducing the situational awareness for construction safety risks management (SA4SR), realizing timely and accurate hazard detection and dynamic risk analysis. Accordingly, the SA4SR consists of two modules: hazard detection and risk awareness. The hazard detection module focuses on identifying safety hazards in near real time with reduced false alarms. Three unsafe-proximity detection models were developed, which can not only identify struck-by-equipment hazards in a timely manner but also reduce false alarms. The effectiveness of these three models in reducing false alarms was evaluated and confirmed in both simulation and field experiments. The risk awareness module is centered on analyzing safety risk levels over time for individual entities and the whole construction sites. A spatiotemporal network-based model with three safety leading indicators was developed to analyze the struck-by-equipment risk at both entity and network levels. The risk analysis at entity and network levels was conducted using four simulated sites, and the derived safety applications were summarized.
The developed SA4SR addressed the limitations of existing proximity detection methods and further developed a dynamic risk analysis model to comprehensively analyze struck-by-equipment risk. The situational awareness is improved by applying the developed models in the SA4SR to analyze sensed data (e.g., motions of entities). Consequently, hazards can be identified, risk evolution can be tracked and analyzed, and safety performance can be evaluated and compared. The developed SA4SR is expected to alleviate safety concerns in the construction industry and also can be extended to other types of contact collisions on sites to further enhance safety.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Energy cost of Walking in Adolescent Boys who differ in adiposity but are matched for total body mass:metabolic and mechanical approaches

contributor:
Bar-Or, Oded
Human Biodynamics

subject: body composition,adolescents,body mass

abstract:
Energy cost of walking at any given speed is higher for heavier people than
for lighter ones. We compared adolescents that were matched for total body
mass but had different body composition. Nine pairs of boys (16.37 ± 1.57 years
in the lean group and 12.90 ± 1.49 years in the obese group) participated.
Metabolic energy expenditure (EE) was compared at three walking speeds and
moments and powers at the hip and ankle at push off were analyzed.
Assessment of fat mass and distribution was performed using whole body dualenergy
x-ray absorptiometry. A repeated measure ANOVA was performed when
matched pairs were compared. Based on multiple regression, pooling all
subjects together, body mass was the main predictor of EE. Variance explained
by adiposity increased with increasing speed. Obese subjects tended to expend
more energy than their lean pairs at the two fastest walking speeds (5 and 6kph).
There was a significant difference between the pairs in EE (kJ/min) at 6kph
(p<0.05). Ventilation showed the same pattern as V02net (exercise V02 minus
resting V02), increasing with increasing speed and showing differences between
the pairs at the fastest speed. Heart rate was consistently higher in the obese
subjects. Stride length, stride rate, progression velocity and moments and
powers at the hip and ankle at push off were not correlated with body fat. No
relationship between V02net. total amount of body fat, or segment fat content was found. Total amount of fat in the body and the amount of fat in the legs had no
influence on gait parameters. In conclusion, excess body fat does not influence
the energy cost of walking at low speeds but does so at 6kph. Obese subjects
demonstrated higher effort at all speeds. Amount of fat distributed in body
segments does not influence either energy cost of walking or mechanical gait
parameters.

abstract: Thesis

abstract: Master of Science (MSc)


title: The Development of Postural control in Children with and without visual impairments

contributor:
Riach., Cindy L.
Science

subject: postural stability, visual impairments,foam surface, anterio-posterior

abstract:
The development of postural stability in children with and
without visual impairments (VI) was compared. Thirty eight subjects (4-
12 years old) without VI and 12 subjects with VI (5- 12 years) took part.
Stability was measured in 4 quiet standing tasks (normal or foam surface,
eyes open (EO) or eyes closed (EC)) and by measuring stability limits
(SL) in the anterio-posterior (a-p) and lateral (lat) planes. Results for
control subjects were compared using Pearson correlation coefficients,
analysis of variance, and analysis of covariance (height as the covariate).
For quiet standing tasks, outcome parameters were the standard deviation
(SO) of the centre of pressure (CP) in the a-p and lat planes, and mean
velocity (vel) of CP movements. For the leaning tasks, SL was measured
(normalized to the base of support) in the a-p and lat planes, and SL was
compared to CP. Individual results for subjects with VI were compared
qualitatively to control subjects.
For control subjects, stability increased with age. Subjects with
VI were less _stable than controls on all outcome parameters. Differences
between groups were more apparent as age increased, particularly for EO
conditions. This could indicate a slower pattern of development for
subjects with VI compared to controls. The groups were different both in
the EO and EC conditions, indicating that postural control with EC is not
the same as postural control with a VI, and that vision is important to the
development of postural control in children.

abstract: Thesis

abstract: Master of Science (MSc)


title: A Model Of Prefrontal-Hippocampal Interactions in Strategic Recall

contributor:
Becker, Susanna
Psychology

subject: evidence, prefrontal cortical, hippocampal, computational network model

abstract:
In this thesis, we look at evidence accumulated on the prefrontal cortical and hippocampal regions of the brain and review theories about the possible roles each structure has on human memory and behaviour.
Aspects of these theories are tested via a self-reinforcing computational network model. We propose this model may simulate the underlying mechanisms or processes of the prefrontal-hippocampal interaction during performance of memory tasks that require intact prefrontal and hippocampal structures.

abstract: Thesis

abstract: Master of Science (MSc)


title: Study of Uniaxial Compression Process for AA7075 Aluminum Alloy

contributor:
Jain, Mukesh
Mechanical Engineering

subject:
AA7075 Aluminum
Compression

abstract: An experimental and complementary FE modeling study was conducted to characterize the room and elevated temperature uniaxial compressive deformation behavior of AA7075-T6 and O-temper materials. The experiments consisted of testing cylindrical and cubic specimens prepared from a rolled and heat-treated plate stock of AA7075 alloy. The tests were conducted in the lower range of elevated temperatures up to 300 °C, at several different test speeds in rolling and transverse orientations, as well as under isothermal and non-isothermal test conditions. The test results were analyzed in terms of true stress-train responses of the two tempers under the above experimental conditions. The deformed test specimens were also observed for surface features and deformed microstructures in the interior of the specimen under the above experimental conditions. A suitable strain rate and temperature dependent constitutive hardening law, in the form of modified Voce-Kocks law, was developed and coded as a UMAT subroutine in ABAQUS FE code to simulate the uniaxial compression experiments and compare the experimental and model results. In general, good general agreement was obtained between experiments and model predictions. A suitable fracture criterion, in the form of Tresca fracture model, was also implemented as a VUMAT subroutine in ABAQUS FE code to simulate the uniaxial compression experiments and predict fracture mode and other characteristics. Once again, good general agreement was obtained between room temperature fracture shapes and model predictions. The experimental and model results collectively provide a broad-based understanding of the effect of temperature, strain rate, material anisotropy, temperature field on material flow and deformed shapes of cylinders and cubic specimens, the nature of deformation (predominantly shear along two intersecting shear directions) and fracture (predominantly shear). The constraints to deformation at the corners in the cubic specimen yielded rather complex curvature development in deformed cubes. The non-isothermal rapid heating of test specimens using electrical resistance heating and subsequent compression of the specimen provided results similar to the isothermal case. However, the electrical resistance method offers a cost-effective process to form smaller high quality components in forming modes such as hot upsetting.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: An Anishinaabe Politics of the International:  Odaenuah, Akina, miniwaa Gchi’naaknigewin

contributor: Political Science - International Relations

abstract: In the discipline of International Relations (IR) Indigenous philosophy and politics has been excused, marginalized and categorized as domestic, at best. Indeed, IR is implicated in both spawning and sustaining settler colonialism in Canada. But Indigenous philosophies of the international are beginning to re-emerge and respond. The first half of this dissertation is an attempt to re-articulate an “authentic” Anishinaabeg international politics. Considering stories, treaty history, and diplomatic practice reveals that relationships within Anishinaabe communities and among non-Anishinaabe individuals and communities (including non-humans) demand autonomy, fluidity and obligation. This is a challenge to core IR concepts of state, sovereignty, and anarchy. The second half of the dissertation shifts attention to settler colonialism and the attendant technologies and discursive fields that support it. While it is clear that Canadian legal and political orders have resulted in tremendous disruption, Indigenous peoples nonetheless continue to enforce their vision of self-determination by manipulating and sabotaging the institutions of settler colonialism. This is a contemporary form of Anishinaabe and Indigenous international politics.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Expression of P2X Purinoceptor Subunits in the Unit Carotid Body Chemoafferent Pathway: Regulation by Chronic Hypoxia

title: P2X Purinergic Receptors in Chemoafferent Neurons

contributor:
Nurse, Colin
Biology

subject: purinoceptor rats chemoafferent hypoxia

abstract: Hypoxic chemotransmission in the rat carotid body (CB) is mediated in part by ATP acting on P2X urinoceptors. Here we use RT-PCR, cloning, and sequencing techniques to show P2X2 and P2X3 receptor expression in petrosal neurons (PN). Confocal immunofluorescence indicated co-localization of P2X2 and P2X3 protein in many petrosal neurons and CB afferent terminals in situ. Petrosal and nodose neurons share a similar developmental origin (i.e. the ectodermal placodes) and GDNF is a required survival factor for both the neuronal groups. However, in the present study the profiles of P2X receptor subunit expression in the petrosal and nodose neurons differed from each other. The PNs showed a slight increase in the expression of P2X2 and P2X3 mRNA by P-21, whereas in nodose neurons the corresponding expression levels peaked by P-9, but fell significantly by P-21. However, in both cases the expression levels for the P2X2 mRNA were higher than those of P2X3 mRNA and the expression profile for both the P2X subunits developed along a parallel time course. Previous developmental studies have indicated that expression levels of various autoreceptors on type I cells (e.g. DA D2-receptors, A2a and A2b adenosine receptors) change during the first week of postnatal life, as the animal breathes normoxic air. In the present study, the possibility that oxygen tension might regulate P2X receptor expression on type I cells was examined. RT-PCR was employed to compare expression levels of the P2X subunits in isolated type I cells grown under different 0₂ tensions. Compared to nonnoxic (20% 02) cell clusters grown under chronic hypoxia ( 6% O₂). Immunofluorescence studies cells grown under CHox. Thus, ATP and P2X2/P2X3 purinoceptors play an important role under normal conditions and following exposure to chronic hypoxia.

abstract: Thesis

abstract: Master of Science (MSc)


title: Comparison of the Metabolic and Behavioral Disturbances Following Paraventricular- and Ventromedial-Hypothalamic Lesions

contributor:
Weingarten, H.P.
Psychology

subject: metabolism behavior lesions ventromedial paraventricular

abstract: Lesions of the ventromedial hypothalamus (VMH) result in an obesity syndrome characterized by metabolic and behavioral disturbances. It  has recently been indicated that damage to the paraventricular nucleus of the hypothalamus (PVH) also leads to changes characteristic of obesity. Although deficits following VMH lesions have been characterized extensively, less is known about the consequences of PVH damage. This thesis presents a series of experiments providing a detailed comparison of the two hypothalamic lesion syndromes. Initially, to assess the basic features of the syndromes, rats underwent VMH, PVH, or sham lesions and were maintained ad libitum for 15 weeks on a series of test diets. Overall, lesion groups gained similar amounts of weight (significantly more than controls) and were equally hyperphagic. However, carcass analyses revealed that although both lesion groups had larger body fat compartments than controls, VMH rats were fatter than PVH animals. Similarly, although insulin levels in both lesion groups were elevated, only VMH rats had a significant hyperinsulinemia. A defining feature of the VMH obesity is the development of certain disturbances of visceral secretion and excessive adipose stores even in the absence of hyperphagia. To assess whether the PVH obesity shares these characteristics, food intake of PVH and VMH rats were restricted postlesion to control body weights. First, gastric acid secretion was measured to index lesion-induced changes in visceral secretion. VMH rats developed a persisting hypersecretion immediately postlesion; acid secretion levels of PVH rats were normal. In a second experiment, PVH and VMH rats were maintained at control weights for 28 days postlesion by restricted feeding of either a standard pellet or high fat diet. In both diet conditions, VMH rats became obese but PVH rats did not. Finally, the effects of PVH and VMH lesions on behavioral reactivity to orosensory properties of food were assessed by comparing the sham feeding responses of PVH, VMH and control rats to liquid diets varying in palatability. Control animals increased sham feeding with ascending sucrose concentrations. VMH animals showed disproportionately large increases in consumption with increased sucrose. PVH animals showed sham feeding changes similar to VMH rats. These data indicate similar effects of PVH and VMH lesions on behavioral measures; specifically, in normal, and sham, feeding. However, these two lesions produce different effects on metabolic and secretion measures. It is concluded that the etiologies of the two obesity are fundamentally different.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Motor Overflow in Nonretarded Children and Down Syndrome Adults

contributor:
Elliott, D.
Adapted Human Biodynamics

subject: motor overflow, children, down syndrome, adults, transfer of training

abstract: Two experiments are reported that examine motor overflow in Down syndrome and nonretarded persons. The two main purposes of the experiments were to determine the utility of motor overflow as a diagnostic tool and the relationship between motor overflow and transfer of training. In Experiment 1, nonretarded children and adults performed a unimanual finger-sequencing task. It was found that motor overflow follows a developmental course. As well, a positive relationship was found between motor overflow and intermanual transfer of training, and children were able to reduce their ipsilateral motor overflow with training. These results indicate that caution should be taken in diagnosing central nervous system dysfunction of a structural nature using motor overflow. In Experiment 2, similar procedures were used to examine younger children and Down syndrome adults. It was found that with conscious effort, even the children could reduce their motor overflow. A positive relationship between transfer of training and motor overflow was also evidenced in Down syndrome subjects. As well, there was greater transfer of training from the left hand to the right hand than the reverse, in both Down syndrome adults and young, nonretarded children. These findings are discussed in reference to factors affecting the appearance of motor overflow and what can be learned about cerebral specialization in nonretarded and special populations.

abstract: Thesis

abstract: Master of Science (MSc)


title: Analysis of a Mathematical Model of a Three-Species Foodweb

contributor:
Wolkowicz, G.S.K.
Mathematics

subject: mathematical model, three-species foodweb, predators, prey, coexistence, bifurcation, orbit

abstract: A model of two predators competing for the same prey also involving predation interaction between the two predators is considered. Coexistence in forms of equilibria and periodic orbits is obtained by using bifurcation and dynamical systems theory. Global dynamics is obtained by studying the survival functions and persistence is obtained by using a theorem of Freedman and Waltman. Finally, numerical results for a specific example demonstrate the above. A Hopf bifurcation at the interior equilibrium and its unstable periodic orbit are observed.

abstract: Thesis

abstract: Master of Science (MSc)


title: Assessment and Optimization of the Canadian SCWR reactivity control systems through reactor physics and thermal-hydraulics coupling

contributor:
Novog, David R.
Engineering Physics

subject: Nuclear Engineering

abstract:
Canadian Nuclear Laboratories conceptualized a new reactor design to fulfill the goals set forth by the Generation IV International Forum. Unlike the traditional CANDU™, the Canadian Supercritical Water-cooled Reactor (SCWR) stands vertically and uses the batch fueling technique. Despite the CANDU-like assembly design, the traditional code system is not adequate to model this concept. Moreover, the current design lacks reactivity control mechanisms to remove the initial excess reactivity and manage the core power distribution.
Fuel-integrated burnable absorber and cruciform control rods were designed for the Canadian SCWR as part of this work. A new genetic algorithm technique has been applied to optimize the control rod pattern by trying to minimize the maximum cladding surface temperature (MCST) and the maximum fuel centerline temperature (MFCLT) through the use of unique surface responses.
The results of the study showed that the MCST and MFCLT did not meet the safety margins during normal operation. Therefore, the concept was enhanced by optimizing the fuel enrichment and burnable absorber concentration along the fuel assembly, shortening the cycle length, reducing the reactivity worth of the individual control rod, and finally lowering the core thermal power. The control rod pattern was re-evaluated and considerably improved the results.
PARCS and RELAP5/SCDAPSIM/MOD4 were coupled through a series of external scripts to simulate 3D neutron kinetics/thermal-hydraulics control rod drop accidents. Every assembly was individually modeled in the coupling to accurately represent the evolution of these localized transients. Fuel melting occurred when the reactor SCRAM was not available. On the contrary, the safety margins were largely met when the reactor tripped on the overpower signal. However, this detection method demonstrated its limitation when one power pulse did not reach the SCRAM signal and led to fuel melting. A local neutron overpower signal could be implemented to ensure the reactor SCRAM in every control rod drop accident.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Processing of LF structure: Evidence from reconstruction for binding

contributor:
Kucerova, Ivona
Cognitive Science of Language

abstract: This thesis investigates whether the human sentence processing mechanism (the parser) is sensitive to effects of interpretation in real-time processing. We aim to better understand how the parser assigns meaning to a given string of words as the words are presented one at a time in left-to-right parsing. We assumed Chomsky (1995)’s Y-model of the grammar following which syntax plays a central role. In this model, the phonological component (Phonological Form, PF) and the interpretative component (Logical Form, LF) are considered separate in the architecture of the grammar. In processing experiments, the parser is presented with the string of words in its pronounced form (roughly, the PF form). To interpret the string of words, it must derive an interpretable structure for that string (LF structure). This thesis examines whether the parser is sensitive to the LF component of the grammar and if so, how it derives interpretable structures in processing. We investigated constructions that are argued to have distinct PF and LF representations (PF-LF mismatch). In the theoretical literature, these cases are known under the label reconstruction. To systematically investigate potential effects of reconstruction, we used constraints on referential dependencies (Binding Theory, Chomsky, 1981), which are argued to be an LF constraint (Fox, 2000; Nissenbaum, 2000; Fox and Nissenbaum, 2004). More precisely, we examined constructions in which binding constraints seem to be violated based on the PF level of representation but are satisfied at LF. In a series of processing experiments, we manipulated whether the phrase containing a determiner phrase could be interpreted upon first encounter or whether it needed to reconstruct to a syntactically lower position to receive an interpretation. Our results suggest that the parser is sensitive to reconstruction effects in the domain of referential processing, providing evidence that the parser is sensitive to PF-LF mismatches. To our knowledge, the experiments reported in this thesis are the first to directly investigate whether the parser is sensitive to reconstruction operations required for semantic interpretation in processing.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Reduced Strength Following Passive Stretch of the Human Plantarflexors

contributor:
Sale, Digby
Human Biodynamics

subject: plantarflexor strength stretch

abstract:
Thesis
Master of Science (MSc)


title: Time-Frequency Analysis of Electroencephalographic Activity in the Entorhinal cortex and hippocampus

contributor:
Haykin, Simon
Electrical and Computer Engineering

subject: oscillatory,electroencephalogram,synchronous activation,neurons,time-frequency techniques,entorhinal cortex,hippocampus

abstract:
Oscillatory states in the Electroencephalogram (EEG) reflect the rhythmic synchronous
activation in large networks of neurons. Time-frequency methods quantify the spectral
content of the EEG as a function of time. As such, they are well suited as
tools for the study of spontaneous and induced changes in oscillatory states. We
have used time-frequency techniques to analyze the flow of activity patterns between
two strongly connected brain structures: the entorhinal cortex and the hippocampus,
which are believed to be involved in information storage.
EEG was recorded simultaneously from the entorhinal cortex and the hippocampus
of behaving rats. During the recording, low-intensity trains of electrical
pulses at frequencies between 1 and 40 Hz were applied to the olfactory (piriform)
cortex. The piriform cortex projects to the entorhinal cortex, which then passes
the signal on to the hippocampus. Several time-frequency methods, including the
short-time Fourier transform (STFT), Wigner-Ville distribution (WVD) and multiple
window (MW) time-frequency analysis (TFA), were used to analyse EEG signals.
To monitor the signal transmission between the entorhinal cortex and hippocampus,
the time-frequency coherence functions were used. The analysed results showed that
stimulation-related power in both sites peaked near 15 Hz, but the coherence between
the EEG signals recorded from these two sites increased monotonically with
stimulation frequency.
Among the time-frequency methods used, the STFT provided time-frequency
distributions not only without cross-terms which were present in the WVD, but also
with higher resolutions in both time and frequency than the MW-TFA. The STFT
seems to be the most suitable time-frequency method to study the stimulation-induced
signals presented in this thesis. The MW-TFA, which gives low bias and low variance
estimations of the time-frequency distribution when only one realization of data is
given, is suitable for stochastic and nonstationary signals such as spontaneous EEG.
We also compared the performance of the MW-TFA using two different window functions:
Slepian sequences and Hermite functions. By carefully matching the two window
functions, we found no noticeable difference in time-frequency plane between
them.

abstract: Thesis

abstract: Master of Engineering (ME)


title: Evaluation of the Length-Tension Relationship in an Elderly Population

subject: dorsiflexors, tetanic contractions, R-tibialis, resting joint, torque

abstract:
The effects of aging on the muscle length (as inferred by
joint angle)-tension relationship was studied in the ankle
dorsiflexors of male and female subjects aged 20-40 years
(x=25.3; 15d, 159) and 60-80 years (x=68.8; 15d, 159) at 10
joint angles {15°0 through 30°P, in 5° increments). Isometric
twitches, voluntary contractions, and 1-sec evoked tetanic
contractions {20, 50 & 80 Hz) were measured in the R-tibialis
anterior muscle. The resting joint angle for the ankle
dorsi flexors was similar between elderly and young adults
{13°P ± 3.44). On average, evoked and voluntary torque output
increased upon muscle lengthening beyond resting length, and
decreased upon shortening. Evoked single twitches of the TA
revealed that peak total torque occurred at the extreme of
plantarflexion (30°P} in both elderly and young adults. Most
importantly, elderly individuals produced similar twitch
torque values at all joint angles compared to young adults.
Maximal voluntary torque was stronger at the more
plantarflexed compared to the dorsiflexed angles, for all
subjects, regardless of age, with maximum torque plateauing at
15°P. Elderly subjects demonstrated much reduced MVC torque
values compared to young adults at all joint angles (ave.= 18%
reduction, p<O.Ol) while maintaining no less than 96% motorunit activation (MUA) . Stimulation of the dorsiflexors at 20,
50, & 80 Hz revealed that the 1-sec peak tetanic torques
declined from a maximum at 30°P through to 15°0 for all
subjects. Elderly adults produced significantly less tetanic
torque at all joint angles compared to young adults (p<0.05).
There was no difference between the elderly and young adults
in the rate at which the rise in tetanic torque was developed
at all joint angles, but elderly adults displayed a
significantly greater twitch/tetanus ratio as compared to
young adults (p<0.005).
In conclusion, these results suggest that there is no
age-associated change in the elastic properties of the ankle
dorsiflexors, and thus, the length-tension relationship of
this muscle group is similar between elderly and young adults.

abstract: Thesis

abstract: Master of Science (MSc)


title: Evaluating the effectiveness of web application testing techniques using automated tools

contributor:
Down, Douglas
Computing and Software

subject: web application, testing techniques, automated tools

abstract:
The heterogeneous structure and dynamic nature of web applications have
made the testing procedure a challenge. Producing high-quality web applications can be performed by conducting appropriate testing techniques. As a result, several white-box and session-based testing techniques have been proposed in the literature. In this work, the performance and effectiveness of these testing techniques are evaluated in terms of fault detection on a simulated PHP online bookstore. The testing techniques are examined with the use of PHPUnit, xDebug and Selenium automated testing tools. We believe that combining the testing techniques with appropriate automated testing
tools (PHPUnit and Selenium) can be effective in terms of fault detection
and time spent to construct and run test cases on PHP web applications. The results show that some testing techniques are preferred. We also identify categories of faults that are amenable to detection by each of the techniques, as well as categories of faults that are difficult to detect by any of the techniques. Moreover, using the automated tools has helped in automating the conduct of the tests and in reducing the time required to perform them.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: The Relationship Between Beta-Blockade, Plasma Potassium Concentrations and Muscle Excitability Following Static Exercise

contributor:
Hicks, Audrey
Kinesiology

subject: beta-blockade, plasma potassium concentrations, muscle excitability, static exercise

abstract:
Abstract Not Provided.
Thesis
Master of Science (MSc)


title: Event-Related Potentials in Global-Local Processing: Lateralization, Parallel Processing and the Effect of Unattended Variability

title: Processing of Global and Local Stimuli: an ERP Study

contributor:
Shedden, Judith
Psychology

subject:
unattended variability
lateralization
parallel processing
event-related probability

abstract: An object in the visual field can be perceived as a whole and as the parts from which the whole is composed. Early investigations into whole-part processing led to the hypothesis that the global aspect, the whole, is processed before the local aspects, the parts. However, recent electrophysiological work shows that in the early stages of processing, the global and local levels of an object are processed in parallel. In addition, a processing asymmetry exists in that the right hemisphere is biased for global level processing whereas the left hemisphere is biased for local level processing. In an ERP study, I examined the lateralization and time-course of global-local processing in normal adult humans and found further evidence for lateralized, parallel processing of global-local stimuli. More importantly, I found that task demands affected the latencies at which lateralized differences between the two levels emerged: a condition in which interference from one level on the other was minimal showed very early, lateralized attentional effects (80 ms). In a relatively more demanding condition, lateralization of global and local processing was not evident until 200-350 ms. One possible explanation is that as the influence of distractors at the unattended level increases, resources in both hemispheres are engaged. To corroborate these findings, I included conditions in which subjects were required to switch attention among levels and visual fields: Evidence for lateralization and parallel processing persisted. Moreover, the additional load placed on the system by the switching conditions was apparent at the N1 component and support for right hemisphere attention switching mechanisms was obtained.

abstract: Thesis

abstract: Master of Science (MSc)


title: The Effect of Cycloserine on Metabolism and Contractile Function in Rodent Skeletal Muscle

contributor:
Gibala, M.J.
Human Biodynamics

subject: cycloserine, metabolism, contractile function, rodent, skeletal muscle

abstract:
 We hypothesized that acute inhibition of the contraction-induced expansion of the muscle TCA cycle intermediate (TCAI) pool via would not adversely effect metabolism or contractile function. Forty rats were anaesthetized and the gastrocnemius muscle (GAS) from one leg was vascularly isolated and perfused with saline (CON) or a red cell media containing DL-cycloserine (CYCLO; Sigma C-7005; dose=0.05 mg/g), an inhibitor of alanine aminotransferase (AAT). After 1h of perfusion, the GAS muscle was either snap frozen (CON-Rest, n=11; CYCLO-Rest, n=9) or stimulated to contract for 10 min (1Hz, 0.3 ms, 2 V) with blood flow fixed at 30 ml min-1 100g-1 and then snap frozen (CON-Stim, n=10; CYCLO-Stim, n=10). The maximal activity of AAT was lower (P≤0.05) at both CYCLO-Rest (0.61±0.02 mmol·kg-1w.w./min; mean± SEM) and CYCLO-Stim (0.63±0.01 mmol·kg-1w.w./min) vs CON-Rest (3.56±0.16 mmol·kg-1w.w./min) and CON-Stim (3.92±0.29 mmol·kg-1w.w./min). Consistent with lower net flux through AAT, muscle [alanine] was lower (P≤0.05) after CYCLO-Stim (6.97±0.26 mmol·kg-1 dw) compared to CON-Stim (8.55±0.56 mmol·kg-1 dw) and not different vs CON-Rest (6.79±0.41 mmol·kg-1 dw). The sum of five measured TCAI (malate,
fumarate, citrate, isocitrate, and 2-oxoglutarate) was higher (P≤0.05) at both CON-Rest
(2.10± 0.09 mmol·kg-1 dw) and CON-Stim (2.48± 0.11 mmol·kg-1 dw) vs CYCLO-Rest
(1.56± 0.11 mmol·kg-1 dw) and CYCLO-Stim (1.88± 0.15 mmol·kg-1 dw) respectively. Despite the reduction in [TCAI] following CYCLO treatment, there was no difference between conditions in muscle lactate accumulation or phosphocreatine degradation after 10 min of stimulation. Contractile function was not different (P≤0.05) between conditions at either rest or stimulation and the decline in force production over ten minutes of stimulation was identical (~60%) between CON-Stim and CYCLO-Stim respectively. We conclude that flux through AAT was reduced after cycloserine treatment, however the acute inhibition of TCAI expansion did not compromise aerobic energy provision. These data support the hypothesis that the contraction-induced increase in muscle [TCAI] is not causally linked to oxidative energy delivery.

abstract: Thesis

abstract: Master of Science (MSc)


title: The Effects of Lactacidosis on Metabolism and Ionic Flux in Inactive Skeletal Muscle of the Isolated Perfused Rat Hindlimb

contributor:
MacDougall, J.
Adapted Human Biodynamics

subject: lactacidosis muscle rat

abstract:
Lactate removal by inactive skeletal muscle was investigated using an isolated rat hindlimb perfusion model under conditions simulating recovery from maximal exercise. The purpose of this investigation was threefold: 1) to quantify the contributions of the oxidative, glyconeogenic, and triacylgylcerol (TG) synthesis pathways to lactate (La) removal, 2) to examine differences in La removal patterns in inactive skeletal muscle of various fiber types, and 3) to investigate the possible mechanisms for La and H⁺ removal by inactive muscle. Male Sprague-Dawley rats were perfused for 60 min, at rest with either a normal perfusate (NP) (N = 8) or a lactacidotic perfusate (LP) (N = 8). The LP perfusate was characterized by elevated concentrations of La (11.0 mMol), K⁺ (7.88 mMol), and hemoglobin (16.7 g·dl⁻¹) and a decreased pH (7.15). Arterial and venous perfusate and soleus (SOL), plantaris (PLT), and white gastrocnemius (WG) muscles were analyzed for various metabolite and ion concentrations. Analysis revealed increased rates of La uptake, glycerol release and C0₂ output in the LP versus the NP group. No difference was observed for O₂ uptake or glucose uptake between the two groups. Tissue anajysis revealed
no significant change in muscle ATP, CP, glycogen, pyruvate, F-6-P or TG concentration pre versus post perfusion in both LP and NP groups. Significant increases were found in muscle La concentration (pre vs post and LP vs NP), with SOL having the highest concentration followed by PLT and WG. Muscle [F-1 ,6-diP], F-1 ,6-diP /F-6-P and pyruvate/F-1 ,6-diP ratios were elevated following LP perfusion indicating glyconeogenic inhibition. Muscle glucose levels decreased in the NP but not LP group, indicating a possible shift in substrate utilization in the LP group. In the LP group, total calculated La uptake by the 3 muscles was 61.0 umole, with 14% accumulating as tissue La post perfusion. Of the remaining 86%, 12-33% could be accounted for by oxidative metabolism, and 5-7% may have been involved in glycerol release. The remaining 60-75% was
unaccounted for, but was hypothesized to have been involved in carbon cycling along the glycolytic/glyconeogenic pathway and/or in TG/FFA substrate cycling. No evidence was found of net glycogen synthesis from La. Increased H⁺ and K⁺ influx and HCO₃⁻ efflux were observed in response to lactacidotic perfusion. Sodium and Cl⁻ exchange patterns showed a net influx over 60 min of LP perfusion. Data from the ionic flux of the various strong ions and non-volatile H⁺ suggested that La is transported into inactive skeletal muscle by various mechanisms, including HLa diffusion, La/H⁺ cotransport, and possibly La/Cl⁻ exchange. The data also suggested that a number of regulatory mechanisms are activated in rat skeletal muscle to maintain intracellular [H⁺] and membrane potential during lactacidotic perfusion. From this investigation it was concluded that, in inactive muscle of the isolated rat hindlimb perfused for 60 min with a lactacidotic perfusate, patterns of La uptake and metabolic elimination are different from those
previously observed for active muscle. The metabolic fates of La appear to be related to the ionic disturbances associated with La and H⁺ influx into inactive muscle. The net ionic movements across the inactive hindlimb appear to be related to the preferred metabolic pathways of La elimination, but whether or not a direct cause and effect relationship exists cannot be stated conclusively.

abstract: Thesis

abstract: Master of Science (MSc)


title: The Effect of Ultrasound Probe Orientation on the Measurement of Muscle Architecture Parameters

contributor:
Dowling, James J.
Human Biodynamics

subject: ultrasound probe orientation, measurement, muscle architecture, parameters, joint angles, tibialis anterior

abstract:
 A slow concentric contraction of the tibialis anterior muscle was imaged using Brightness-Mode Ultrasonography (BMU) from different probe orientations to determine the effect of probe orientation on the measurement of muscle architecture parameters (MAP). Nine contractions were performed by each of nine subjects. Each contraction was visualized with a different probe orientation on the anterior surface of the muscle. Data was taken from the same four joint angles from all contractions from all subjects and then compared for values of torque, tibialis anterior EMG and measures of MAP which include; fascicle length (FL), pennation angle (PA) and muscle thickness (MT).

 The results of an analysis of variance found a significant difference between joint angles for measures of FL and PA but not MT. A significant difference was found between probe rotations for the measures of FL and MT but not PA.

 A reliability study was performed for measures of MAP and found the coefficient of variation for FL and PA to be less than 8% both with and without the use of an image filter. The coefficient of variation for MT was found to be less than 2% which shows this
measure to be highly reliable.

 Equations and Figures were developed, corresponding to the observations and assumptions made by MAP researchers using BMU, to predict the effect of probe orientation on the measures of MAP.

 The results of this study indicate that ultrasound probe orientation affects measures of MAP but the effect either cannot be predicted from a simple geometric model or the error in the measurement technique does not allow this type of comparison. Specific guidelines are outlined in this paper to determine the proper probe placement and orientation to measure MAP using BMU for the tibialis anterior muscle.

abstract: Thesis

abstract: Master of Science (MSc)


title: Neocortical Evoked Potentials: Effects of Environmental Enrichment and Electrical Stimulation

contributor:
Racine, R. J.
Psychology

subject: neocortical evoked potentials, environmental enrichment, electrical stimulation, synaptic transmission

abstract:
 Alterations in neural tissues associated with environmental variables have been studied for many years. Anatomical changes in the neocortex of rats in response to exposure to complex environments were observed and replicated in a number of studies both within and across species. These changes are not dependent on the age of the animal or on the duration of exposure, and have been demonstrated in structures outside of the cortex. Due to the undisputed involvement of both the neocortex and the hippocampus in learning and memory,
researchers applied a widely used model system of a synaptic mechanism for learning, long-term potentiation (LTP), to the environmental enrichment paradigm and demonstrated significant enhancements in hippocampal field potentials in enriched rats. The present study examines whether the neocortex also showed evidence of plasticity in synaptic transmission. No effects for environmental enrichment were observed on the maximum amplitude of neocortical field responses evoked from the corpus callosum. To assess the plasticity of the
chronic preparation used in the study, the animals were exposed to trains of pulses previously shown to induce electrical LTP in the cortex, but revealed only a slight, although significant, depression of the evoked response amplitude. An alteration in the stimulation parameters did not result in an enhanced response. Cortical depth measures suggested that the enriched environment was indeed sufficient to produce plastic changes in anatomy, if not in the efficacy of synaptic transmission. The importance of these findings in the neocortex leads us to
question the validity of the LTP model of learning and memory.

abstract: Thesis

abstract: Master of Science (MSc)


title: Firebugs, Rustlers, Vandals and Vigilantes: Crime & Criminal Justice in Late 19th & Early 20th Century Rural Ontario

contributor:
Cruikshank, Ken
History

subject:
Canada
Ontario
History
Rural
Crime
Criminal Justice

abstract:
In the late nineteenth and early twentieth centuries, the provincial system for administering justice in rural Ontario was criticized in the press and by some local justice officials in the counties. Criticisms were in response to apparent moments of criminal crisis. The public learned about the crimes of violent groups and gangs mainly through the press. There were stories of sensational property crime, violent attempts at social control, and more rarely, vigilantism.
       Ontario, however, appeared to be a peaceable province, which moderated calls for improvement in the system. The slow pace of reform, and evidence of a system that functioned well under most circumstances, suggests that the province had only marginal interest in reform.
	An antiquated system of rural constables was useful to critics advocating reform. In some cases however, the local knowledge of the county constable complimented the investigative strength of the provincial detectives. The rise of the Ontario Provincial Police in the 1910s and 1920s promised a change for the better, but the force was not designed to meet the needs of rural Ontarians, and did not take over rural policing until 1929. The challenges faced by the force in its early years, as well as issues of performance, leaves open for consideration the extent to which crime management in rural Ontario actually improved.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Hypoxia-Induced amine secretion from rodent carotid body and adrenal chromaffin cells: Evidence against NADPH oxidase as an 02 sensor

contributor:
Nurse, Colin A.
Biology

subject: oxygen,mammalian carotid body,glomus cells,neurotransmitters

abstract:
An adequate supply of oxygen (02) is essential to the survival of all higher
organisms. The mammalian carotid body, located at the common carotid artery senses
blood levels of 0 2, carbon dioxide (C02) and acidity. Glomus cells, or type I cells in the
carotid body are the main 0 2-sensors which regulate blood p02 via reflex control of
ventilation. The carotid body secretes multiple neurotransmitters including dopamine
(DA), which is potentiated during low p02 levels and is thought to modulate sensory
signaling by apposing afferent nerve fibers. Catecholamine (CA) release is also critical
for the animal's ability to survive hypoxic stress associated with the birthing process and
the transition to extrauterine life. However, the source for this CA release (primarily
epinephrine; EPI) is from adrenal chromaffin cells. The primary 02-sensor in both
adrenal chromaffin cells and carotid body type I cells is unknown. One potential
candidate is the cytochrome b55s/NADPH oxidase complex that generates the respiratory
burst in phagocytes. To test this hypothesis, cultured adrenal medulla chromaffin cells
and intact carotid bodies from wild type (WT) and oxidase deficient (OD) mice
(knockout gp91 phox, the glycoprotein subunits in the NADPH oxidase complex) were
investigated. High performance liquid chromatography and immunocytochemistry were
used to quantify amine release in these two chemoreceptors following exposure to
hypoxia. Both WT and OD chromaffin cells and carotid bodies responded to the hypoxic
challenge with increased monoamine secretion. Norepinephrine and epinephrine were the
principal amines released from chromaffin cells, compared to dopamine and serotonin
from carotid bodies. These findings suggest that NADPH oxidase is not the primary 02-
sensor in either chemosensory system. Quantification of monoamine secretion in intact
carotid body from mouse and rat was also compared under basal conditions and after
exposure to hypoxia and acid/hypercapnia (pH 7.10). Significantly larger amounts of
basal serotonin was secreted from mouse carotid body as compared to the rat.
Interestingly, serotonin release was potentiated by hypoxia in mouse carotid body, but
this was not observed in the rat. Additionally, ratio of basal level serotonin-to-dopamine
secretion was significantly higher in mouse than rat CB. Surprisingly, acid/hypercapnic
(pH 7.1 0) had no detectable effect on amine secretion from either mouse or rat carotid
body.

abstract: Thesis

abstract: Master of Science (MSc)


title: Performance and Neuromuscular Adaptations to Heavy Resistance and Ballistic Training

title: Adaptations to Ballistic and Heavy Resistance Training

subject: ballistic torque electromyography neuromuscular

abstract:
The purpose of this investigation was to compare performance and neuromuscular adaptations following ballistic and heavy resistance training. Twenty male university students were divided into a training (n=10) or control group (n=10). Each subject in the training group, by random assignment, trained the elbow extensors of one arm with heavy resistance (HR.) [(5 sets of the maximal weight that could be lifted for 5-7 repetitions (reps.)]; the other with ballistic (BL) actions (5 sets of 6 reps. at 10% of their isometric MVC). Training was done 3 times per week for 17 weeks. Following training, both training HR. and BL regimens produced significant (p≤0.05), but not significantly different increases in ballistic performance peak torque (2.5 vs. 2.7 N·m, peak velocity (1.0 vs. 1.3 rad·s⁻¹), and peak power (32.8 vs. 48.4 W). Similarly, elbow extension movement time decreased to the same extent (-12.5 vs. -6.3 ms; p≤0.05). In contrast, HR training produced significantly greater increases in maximal weight lifting (I RM) (15.8 vs. -0.1 N·m; p≤0.001) and isometric (MVC) strength (8.1 vs. 0.8 N·m; p≤0.01). Electromyography (EMG) recordings of the agonist (AG) triceps brachii indicated significant (p≤0.05) increases in average EMG (AEMG) during I RM, MVC, and ballistic tests (collapsed across training conditions). The only difference between training regimens was the greater 1 RM AEMG after HR. training. Ballistic training resulted in significantly (p≤0.05) greater antagonist ballistic/MVC, and antagonist coactivation (ballistic/MVC) EMG ratios compared to HR. training. Evoked isometric twitch torque and torque-time integral increased only after HR training. Fiber (needle biopsies of triceps) area increases were also significantly (p≤0.001) larger in the HR than the BL arm after training in type I (28.0% vs. -4.7%), type IIa (43.0% vs. 8.3%), and type IIb (41.4% vs. 3.0%) fibers. Dual photon x-ray absorptiometry regional arm analysis revealed that only the HR. arm significantly (p≤0.05) increased in lean mass following training. Heavy resistance training resulted in a significant (p≤0.05) decrease in the percentage of type IIb fibers with a corresponding increase in IIa; whereas ballistic training did not result in any fiber type conversion. These data suggest that although neuromuscular adaptations may differ, either form of training can increase ballistic performance, but only HR. training is effective in increasing muscle size and maximal force during I RM and MVC single joint actions.
Heavy Resistance, Ballistic, Torque, Velocity, Power, Electromyography, Evoked Contractile Properties, Fiber Type, and Fiber Area

abstract: Thesis

abstract: Master of Science (MSc)


title: CLEFT-Q: Development of a Patient-Reported Outcome Measure to Provide Clinically Meaningful Outcomes in Patients with Cleft Lip and/or Palate

contributor:
Klassen, Anne
Health Research Methodology

subject:
patient-reported outcomes
cleft lip and/or palate
CLEFT-Q

abstract:
Background: The management of cleft lip and/or palate (CL/P) includes multidisciplinary care beginning in infancy and continuing through to adulthood. Outcomes of cleft care have been difficult to measure because of the subjective nature of evaluating concepts such as appearance and speech. Including the patient perspective in outcome evaluation through the use of a patient-reported outcome (PRO) measure would provide a more accurate reflection of a patient’s status. The overall objective of this thesis is to show that through adherence to rigorous methods of development, a PRO measure can provide clinically meaningful outcome evaluation in cleft care.
Methods: The first paper uses the qualitative method of interpretive description to define a conceptual framework to guide the development of a PRO measure for patients with CL/P, the CLEFT-Q. The second paper describes the protocol for the entire development of the CLEFT-Q. The third paper analyzes the results of the cross-sectional field-test of the CLEFT-Q scales to determine whether or not the CLEFT-Q is able to detect differences between specific cleft types.
Results: The qualitative study included 138 patients with CL/P from six countries. The final conceptual framework contained thirteen concepts within the domains of appearance, facial function, and health-related quality of life. The second paper details the process of designing the CLEFT-Q scales. The field-test included 2,434 patients from thirty sites in twelve countries, and CLEFT-Q scores were found to vary with cleft type for all scales.
Conclusions: PRO measures need to be rigorously designed in order to provide scientifically sound, clinically meaningful measurement. The CLEFT-Q is able to detect differences between patients with various cleft types, and will be a useful tool to provide the patient perspective in future outcome evaluation in cleft care.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract: Measuring outcomes of treatment for cleft lip and/or palate (CL/P) should include the patient perspective. The objective of this thesis is to show that through rigorous methods of development, a patient-reported outcome (PRO) measure, the CLEFT-Q, can provide clinically meaningful evaluation of outcomes. First, 136 patients with CL/P from six countries were interviewed to learn what concepts related to having a cleft or its treatment are important to them. A conceptual framework was developed that informed the CLEFT-Q scales. Describing the methodology behind developing the CLEFT-Q then served to inform and engage members of the community. A field-test of the CLEFT-Q scales showed that in a sample of 2,434 patients with CL/P from twelve countries, CLEFT-Q outcomes varied in patients with different types of CL/P. The CLEFT-Q can be used to provide rigorous measurement of PROs in patients with CL/P in the future.


title: Interaction of Two Sets of Pacemakers in Canine Ileum: Neuromodulation, Ca^2+ - Dependence, and Electrical Coupling

contributor:
DeBruin, Hubert
Daniel, Edwin
Electrical and Computer Engineering

subject: pacemakers canine ileum neuromodulation electrical

abstract:
We investigated the origins, neural modulation, ionic mechanisms, and electrical coupling properties of the pacemaker systems in the canine ileum by simultaneously recording the intracellular electrical activity and accompanying mechanical activity in cross-sectioned slabs of the muscularis extema or in the isolated circular muscle. In the whole thickness preparation, intracellular recordings were taken from the circular muscle near the myenteric plexus (MyP), deep muscular plexus (DMP), and intermediate areas between the MyP and DMP and in the isolated circular muscle preparation from similar areas except near the myenteric plexus. One type of slow wave, sigmoidal or triangular in shape, was recorded from impalements near the DMP region in the whole-thickness preparation. Another type observed from the MyP region oscillated at nearly the same frequency (9-10 cycles/min) and was characterized by a fast upstroke and a square shape. A mixture of these two patterns was recorded in intermediate areas (the outer circular muscle or OCM) while triangular slow waves were present near the the submucosal plexus (SMP) inner circular muscle. Neither type of slow waves was affected by atropine, guanethidine, propranolol, and phentolamine (all 1 μM). Under these conditions of inhibition of NANC (non-adrenergic, non-cholinergic) nerves, electrical field stimulation (EFS) produced a fast, monophasic inhibitory junction potential (IJP) followed by a triggered slow wave (TSW) which could be premature or delayed and whose amplitude was maximum near the MyP region and decayed progressively in the other areas (minimum in SMP region). The K+ channel blocker, apamin at 10⁻⁶ M, did not affect resting membrane potentials or spontaneous slow waves but inhibited the amplitude of the IJP up to 70% and slightly but significantly enhanced (30%) the amplitude of the TSW. Long duration, single pulses (50-100 msec square waves, 10-20 V) elicited TSWs without IJPs. Both the slow waves and TSWs were associated with contractions of circular muscle which were significantly enhanced by apamin but not by blockers of adrenergic and cholinergic nerves. When the IJPs recorded near the MyP or DMP were abolished by tetrodotoxin (TTX, 1 μM) or by the NO synthase (NOS) inhibitor, N^ω nitro L-arginine (L-NNA, 50 μM), the occurrence of the TSW in response to EFS was advanced in time and increased in amplitude. The effects of L-NNA were reversed by L-but not D-arginine (both 1 mM). L-arginine significantly prolonged the durations of IJPs from the MyP and DMP regions. In contrast, the N-type Ca²⁺ channel blocker ω-conotoxin GVIA (ω-CTX, 1-3 x10⁻⁷M) abolished the IJP but delayed the induction of the TSW. Subsequent addition of either TTX or L-NNA advanced the onset of the TSW. The TSWs elicited by 50-100 msec single pulses were resistant to TTX, ω-CTX, or L-NNA. All treatments which abolished the IJP significantly increased contractions of circular muscle associated with spontaneous slow waves and TSWs. In the isolated circular muscle preparation (with the DMP intact) triangular slow waves were recorded near the DMP or close to the MyP border. The frequency and amplitude of the slow waves recorded near the DMP were significantly smaller than those recorded in similar areas in the full thickness preparation. EFS of this preparation evoked IJPs of 18-20 mV in amplitude. The IJPs were biphasic, lasted 5s and showed a fast and a slow component. No TSW occurred after the fast component of the IJPs; slow repolarization was observed instead. Long duration single pulses did not induce TSWs. In this preparation, the NOS inhibitor, N^ω nitro L-arginine methyl ester (L-NAME, 3x10⁻⁴ M), abolished the IJPs and regularized the slow waves, but TSWs could not be evoked. Superfusion of inhibitory neuromediators had different effects on pacemaking activity. SIN-1, a donor of NO, hyperpolarized the membrane, significantly increased slow wave frequency but reduced its amplitude, and abolished contractions. VIP (less effective) and PACAP (more effective) reduced slow wave frequency and amplitude without changing resting membrane potentials. P ACAP, but not VIP, increased circular muscle tone at 10⁻⁶ M.
Nifedipine (10⁻⁷ and 3 X 10⁻⁷ M), an L-type calcium channel blocker, did not modify the shape of slow waves in any area of the full thickness preparation. It also did not reduce the amplitude of the IJP or TSW. Ni²⁺ at 200 μM, a Ca²⁺ channel blocker, inhibited slow wave frequency and amplitude and contractions. In Ca²⁺ -free Krebs (0.1 mM EGTA) for 10-15 min, the amplitude and frequency of the slow waves were gradually reduced. The TSW in response to 100 msec single pulses was still recorded near the MyP but never near the DMP region. The inhibitory effect of Ca²⁺ -free solution on slow wave amplitude was more rapid in onset near the DMP region. The intracellular Ca²⁺ store pump inhibitor, cyclopiazonic acid (10-30 μM), enhanced slow wave frequency and contractions. This differential sensitivity to removal of Ca²⁺ may be related to the morphological and functional observations which suggested that different electrical coupling properties between the pacemaker networks existed. The MyP pacemakers were less electrically well-coupled by visible gap junctions (low resistive cell-to-cell contacts) to outer circular muscle and hence showed greater susceptibility to 1 mM octanol (a gap junction blocker). The DMP pacemakers made numerous gap junction contacts to circular muscle, and slow waves paced from this region were less susceptible to 1 mM octanol. We conclude that 1) the pacemaker system of the canine ileum consists of two types of pacemakers that correspond to the presence of two networks of pacemaker cells found in the MyP and the DMP. The MyP network appeared to dominate pacemaking activity. 2) The slow waves and the TSW originated independently of neural activity but were delayed by IJPs. The MyP and the DMP provide two independent inhibitory neural inputs, where NO is released to mediate IJPs and relaxation and influence the delay in the occurrence of the TSW. 3) The TSW originates exclusively from the MyP region from which it spreads passively to other areas. It can reset the timing of slow waves in both pacemaker networks. 4) Ca²⁺ entry through non L-or N-type Ca²⁺ channels initiates slow waves. Intracellular Ca²⁺ stores modulate slow waves. 5) Different nature of electrical coupling of the MyP and DMP pacemakers to circular muscle may explain the differential sensitivity of slow waves to Ca²⁺ removal and gap junction blockade.

abstract: Thesis

abstract: Master of Engineering (ME)


title: Positive Time-Frequency Distribution Analysis of the Human Colonic Electrical Activity

contributor:
Huizinga, Jan
de Bruin, Hubert
Electrical and Computer Engineering

subject:
time-frequency
colon
electrical activity

abstract: The electrical activity recorded from the human colon could play an important role in analyzing the pattern of contractions under different physiologic or experimental states. In general, the frequency of the electrical activity is extremely irregular and time-varying. Its analysis requires a technique that considers variations in both time and frequency domains. The research undertaken was to analyze time-frequency variations of the human colonic electrical activity, to implement positive time- frequency distribution techniques in a computer system and to analyze theoretical signals using this technique to characterize a kernel function. Our results show that the uncertainty coefficient together with the marginal conditions and the average of the conditional PTFD in time and also in frequency can be applied to determine which kernel function and c-value were appropriate for calculating the PTFD of a sinusoidal signal. The selected kernel function constituted a comparative template of signals with similar characteristics. We found that those results were useful in analyzing the time- frequency variations of the electrical activity recorded in the human colon. The comparison of relative contributions of frequency bands showed that the band with the highest values during the pre- and interprandial period was 30-40 cpm suggesting an important role in the generation of bursts of these signals. The numerical results suggested that a meal can induce changes in the relative importance of frequencies below 10 cpm and a significant change in the 30-40 cpm band. In addition, a computer program of the Chakravarti method was implemented to calculate the Fourier transform of nonperiodical signals. This program was part of the computer program system developed to compute the PTFD of theoretical and experimental signals.

abstract: Thesis

abstract: Master of Engineering (MEngr)


title: A Software Tool for Integrated Biomechanical Analysis of Elbow Extension

contributor:
deBruin, H
Electrical and Computer Engineering

subject: software tool,data processing and graphing, interactive graphs, calculations

abstract:
This thesis describes a software tool used to study the biomechanics of elbow
extension. The tool is an integrated computer program for data processing and graphing,
and is used in the development of an EMG driven muscle model for dynamic ballistic
muscle movement. The software is designed to manipulate data from a series of
isometric and dynamic elbow extension experiments. Inputs include recordings from a
torque sensor, load cell, and potentiometer as well as EMG from triceps and biceps
muscles. Calculations are made to determine the effect of gravity, the Moment of Inertia,
as well as the force-EMG, force-length and force-velocity relationships. Additionally,
fatigue tests and postactivation potentials are analyzed. Modeling parameters are derived
from isometric controls and verified by applying them to data from dynamic experiments.
The principal design requirements for this software tool were adaptability, user
control, and data processing protocol verification. The majority of data processing
parameters can be controlled and adjusted by the user. Care was taken during software
coding so that it would be easy to modify each step of the protocol and if necessary, add
additional processing. Data is displayed on interactive graphs to provide control
feedback to the user.

abstract: Thesis

abstract: Master of Engineering (MEngr)


title: Energy Transfer Theory Between ER3+ Ion and Silicon Nanocrystal in Optical Cavity and Electric Field

contributor:
Huang, Wei-Ping
Electrical and Computer Engineering

subject: energy transfer theory, ER 3+ ion, silicon nanocrystal, optical cavity, electric field

abstract:
 The need for higher bandwidth and people's desire to be "always connected" have
spurred a new era of silicon photonics. The traditional integrated electrical transmission lines have been an obstacle preventing ultra high speed communication. Using monolithic chips of integrated optoelectronic circuits from silicon provides an economic way to realize Tetra Byte/Second bandwidth in a variety of areas such as "fiber to the home" and the buses linking chips inside computer.

 The heart of such optoelectronics-silicon laser-is still in pursuit. One of the most promising approaches is the erbium doped silicon nanocrystals embedded in silica system. External photon or hot electrons injection excites the silicon nanocrystals, which then transfer their energies to nearby erbium ions to emit light at 1.55 μm wavelength range.

 In this thesis, we investigate the effects of cavity and electric field on energy transfer from Si nanocrystals (Si-nc's) to Er ions, and simulate material gain in such systems. Our results show that microcavity can enhance the Forster energy transfer and material gain, reducing the requirements for Si-nc pumping. The electric field will hinder the radiation decay of Si-nc, but we have to further explore the tunneling mechanism before concluding the overall effect of electric field. Some future work needs to be done, which will shine some light on the design of the silicon laser.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Statistics of Photon Paths in Tissue During Diffuse Reflectance Spectroscopy

contributor:
Patterson, M. S.
Health and Radiation Physics

subject: statistics, photon paths, tissue, diffuse, reflectance spectroscopy

abstract:
 The rapid development of the use of lasers in therapeutic and diagnostic medicine in the past few years has generated interest in measuring the optical properties of tissue. In particular, the development of photodynamic therapy (PDT) has necessitated studies of the optical properties of tissue at wavelengths around 630nm, this being the wavelength at which the photosensitizer commonly used in PDT, namely dihematoporphyrin ether (DHE), is normally activated.

 The control of the volume of tissue from which information about the interaction coefficients of the tissue is obtained is an important problem in diffuse
reflectance spectroscopy and other applications of light, because it is critical to understanding which tissue volumes are sampled by the injected photons that eventually are re-emitted. This report describes a simple model that predicts the parameters that control the volume of tissue interrogated by photons during reflectance spectroscopy.

 In optical fiber based diffuse reflectance spectroscopy, incident radiation is applied at one point on a tissue surface and collected at another point, a radial distance, r, away. Information about the light multiply scattered by the tissue is used to deduce optical scattering and absorption coefficients of the tissue. In this report both steady state and pulse techniques are studied. In the steady state method, the spatial dependence of the backscattered light is the measured
quantity, while the pulse technique uses the temporal broadening of a picosecond
(ps) pulse to determine the interaction coefficients.

 The relative contribution of a volume element of tissue to the observed signal depends on its location, the measurement geometry and the optical properties of the tissue. Knowledge of this dependence would allow some control of the volume interrogated by reflectance spectroscopy, and would provide insight into the influence of inhomogeneities.

 In the work reported here a simple diffusion model of light propagation in tissue based on the Boltzmann radiative transfer equation has been used to derive mathematical expressions for the relative time spent by photons in a given tissue volume element. Using optical interaction coefficients typical of mammalian soft tissues, results are presented for both steady state and pulse irradiation in
both semi-infinite and infinite media.

 The residency time depth profile calculated by this model for index matched and zero fluence boundary conditions has the same shape as that predicted by Weiss (1989), who used a somewhat different model based on a 3-dimensional random walk theory. These profiles are characterized by a build-up region near
the surface and exponential fall far away from the surface in the 'diffusion region'. The influence of the absorption coefficient μa and the fiber separation on the residency time as predicted by this model is in good agreement to that predicted by the random-walk theory (i.e the depth-profile of the residency time tends to sharpen as the absorption coefficient increases. This is attributed to the fact that long trajectories are less likely with large absorption probabilities. As well, the greater the fiber separation, the wider and flatter the depth distribution of the residency time. This is because photons that reach the surface at greater r values have, in general, migrated farther from the immediate vicinity of the source
and detector and hence have sampled a larger volume of tissue). All the integrations in this report were performed numerically using the IMSL/LIB on the Microvax computer system in the Hamilton Regional Cancer Center. The adequacy of this numerical integration was tested and was found to be good.

 This model therefore suggests that during diffuse reflectance spectroscopy, the volume sampled by re-emitted photons can be controlled by changing parameters such as the fiber separation (in both steady state and time-resolved
techniques) and the detection time (in the time-resolved method).

abstract: Thesis

abstract: Master of Science (MSc)


title: Effect of Postactivation Potentiation on Isotonic Knee Extension Performance

contributor:
Sale, Digby
Human Biodynamics

subject: postactivation, potentiation, isotonic, knee extension, performance


title: Changes in Skeletal Muscle Ultrastructure and Strength Performance following acute resistance exercise

contributor:
MacDougall, J.D
Human Biodynamics

subject: muscle ultrastructure, concentric phrase,elbow flexors,biceps brachii, electron microscopy

abstract:
The purpose of this study was to examine changes in
muscle ultrastructure and strength performance following a
single bout of elbow flexor resistance exercise. Eight
untrained males performed 8 sets of 8 repetitions at 80%
concentric 1 RM. One arm performed only the concentric (CON)
phase of the movement while the other performed only the
eccentric (ECC) phase. Maximum isometric (MVC), low (LV} and
high velocity (HV} concentric peak torque, and evoked
contractile property measurements of the elbow flexors were
made before and after the bout, and at 24, 48, 72 and 96 h.
Needle biopsies were obtained from the biceps brachii prior to
the exercise, immediately post-exercise from each arm (POSTCON,
POST-ECC}, and 48 h post-exercise from each arm (48H-CON,
48H-ECC). Electron microscopy was used to quantify the extent
of fiber disruption in each sample. The severity of
disruption was classified as focal (FOC}, moderate (MOD}, or
extreme (EXT}. All strength measurements decreased (P s; o. 05}
below pre-exercise values immediately post-ex in both arms,
but dramatic differences were observed between arms during the
subsequent recovery period. MVC, LV, HV and peak twitch
torque (PTT) recovered to pre-ex values by 24 h in the CON
arm. In the ECC arm, HV did not recover for at least 72 h,
and MVC, LV and PTT remained depressed at 96 h. ANOVA
revealed a greater (P s; 0.05) number fibers were disrupted in
the POST-CON, POST-ECC, 48H-CON and 48H-ECC samples compared
to BASE. Significantly more fibers appeared disrupted in the
POST-ECC (82%) and 48H-ECC (80%) samples compared to the POSTCON
(33%) and 48H-CON (37%) samples, respectively. In
addition, the POST-ECC (41%) and 48H-ECC (50%) samples
contained a greater number of fibers with EXT disruption
compared to the POST-CON (13%) and 48H-CON (17%) samples.
Decreases in MVC at 48 h correlated (P ~ 0.05) with the extent
of EXT disruption in the 48H-CON and 48H-ECC samples. These
data indicate that both the CON and ECC phase of weightlifting
produce myofibrillar disruption, with the greatest disruption
occurring during the ECC phase.
This study was supported by the Natural Sciences and
Engineering Research Council of Canada.

abstract: Thesis

abstract: Master of Science (MSc)


title: Automatic Estimation of the Number of Muscle Motor Units

contributor:
de Bruin, H
Electrical Engineering

subject: muscle motor automatic

abstract: A manual method of estimating the number of functional motor units within a selected muscle has been implemented as an automatic system. The system has been developed in FORTRAN 77 on a PDP-11/34 minicomputer. This system employs closed loop control of the stimulator, thus eliminating any active role of the operator during the testing. The heuristic decision-making processes required of the operator in the manual method have been analyzed and replaced with a defined algorithm incorporating quantifiable decision criteria. The automated motor unit counting system has been demonstrated using a number of human subjects. The system is suitable for use in a research clinical environment, providing a flexible tool for clinical trials or for further development of the technique.

abstract: Thesis

abstract: Master of Engineering (MEngr)


title: Motor Unit Estimates Through Accelerometry

subject: motor accelerometry

abstract: Accelerometers were used to measure evoked peak limb acceleration (EPLA) for the fourth (index) finger. EPLAs were used to investigate force properties of motor units (MUs) and estimate their numbers in the first dorsal interosseous (FDI) through clustering in the force versus stimulus amplitude relationship. This system was semi-automated using a personal computer with A/D and D/A facilities. Upon repeated excitation, some MUs would potentiate and increase their force contribution by 3 to 4 times. It was found that MU number estimation procedures based on force that do not consider twitch potentiation may be underestimating MU numbers. A disadvantage of using EPLA for MU estimation is that sensitivity may vary between subjects due to finger weight and joint dynamics.

abstract: Thesis

abstract: Master of Engineering (MEngr)


title: The Effect of Age and Gender on the Relative Fatigability of the Human Adductor Pollicis Muscle

subject: fatigue resistance, mid-follicular phase, voluntary contractions

abstract:
The purpose of this study was to examine the relationships between age, gender
and fatigue resistance, and further, to determine the relative influence that estrogen status,
membrane excitability, absolute force and muscle length have over the development of
fatigue. A total of 48 subjects, classified by age and gender participated in this study; 12
young males (25.3 ± 2.1 yrs.), 12 young females (23.5 ± 2.1 yrs.), 12 elderly males (71.7
± 5.6 yrs.) and 12 elderly females (69.5 ± 4.6 yrs.). The young females were all
eumenorrheic, not taking oral contraceptives and tested in the mid-follicular phase of the
menstral cycle. None of the elderly females were on hormone replacement therapy.
A 3 minute paradigm of intermittent maximal voluntary contractions (MVC) was
used to fatigue the adductor pollicis muscle, in which 5s MVC's were alternated with 2s
rest periods. In addition, maximal twitches were evoked in each 2s rest period.
No gender difference in fatigability was evident between young males and young
females when considering the fatigue index of the evoked twitch (FI-PT) (young males:
39.8 ± 26.7%, young females: 36.6 ± 19.0%). There was also no gender difference in
fatigability found between elderly males and elderly females when considering the FI-PT
(elderly males: 24.9 ± 26.6%, elderly females: 16.4 ± 48.9%). However, potentiation of
the evoked twitches during fatigue may have confounded these measures.
When considering the changes in voluntary force during fatigue, there was a
strong trend for a gender by time interaction between young males and young females.(p=0.06), which suggests that the former were more fatigable. The trend for this gender
difference was also apparent in the voluntary fatigue index (FI-MVC) (young males: 44.7
± 10.5%, young females: 37.8 ± 14.1 %; p=0.12). Similarly, young males had a
significant decrease in M-wave amplitude during the fatigue protocol and a trend for a
decrease in M-wave area (p=0.08), while young females showed no significant decreases
in either M-wave measure during the fatigue protocol.
There was no gender difference found between the elderly males and elderly
females when considering the FI-MVC (elderly males: 24.2 ± 10.7%, elderly females:
26.3 ± 14.5%). Both groups also showed small but significant reductions in theM-wave
amplitude during the fatigue protocol, although M-wave area was well maintained.
The fact that a strong trend for a gender difference in fatigability was found in the
young subjects but not the elderly subjects, suggests that estrogen may possess fatigue
resisting properties, even during short duration exercise in which glycogen depletion is
not a concern.
With respect to the age-related differences in fatigue, elderly males were found to
be significantly more fatigue resistant than young males as indicated by the FI-MVC
(p<0.01), and the significant age by time interaction during the fatigue protocol (p<0.01).
In contrast, only a trend was found for an age by time interaction between the young and
elderly females during the fatigue protocol (p=0.06). This trend for an age-related
difference in fatigue amongst women was also reflected in the FI- MVC (p=0.13).

abstract: Thesis

abstract: Master of Science (MSc)


title: Cortical Processing of Pain Perception in Humans: A Functional Magnetic Resonance Imaging Study

contributor:
DeCatanzaro, Denys
Psychology

subject: pain corticol humans processing

abstract: There have been numerous studies of pain perception in humans using a variety of brain imaging methods. The majority of the past research has focused on the use of positron emission tomography (PET) as the primary imaging method. The present study examines the cortical mechanisms of pain perception in humans using a recently developed imaging technique called functional magnetic resonance imaging (fMRI). The primary interest in this study concerns how behavioural aspects of pain are reflected by cerebral cortical activity during noxious stimulation. As pain involves a combination of sensory, emotional, and cognitive responses, the extent and degree of activation in cortical areas associated with these responses can be affected. To address this issue, a behavioural experiment was first performed to assess the sensory, emotional, and cognitive components of tonic pain induced by a cold foam-pack (0°C). Subsequently, three subjects from the behavioural study pool participated in the imaging study of pain. In the imaging experiment, a cold foam-pack (0°C) and a non-cold foam-pack were applied to the left hands of these subjects. Activation produced by the noxious stimulus was compared with that produced by the innocuous stimulus. The results revealed inconsistencies in cortical activation among the three subjects and this could be related to each subject's behavioural measures. Individual and experimental variables may also account for the differences in results.

abstract: Thesis

abstract: Master of Science (MSc)


title: The Effect of B-Blockade on Skeletal Muscle Excitability and Fatiguability During Exercise

title: B-Blockade and Skeletal Muscle Function During Exercise

contributor:
Hicks, Audrey
Physical Education

subject:
skeletal muscle
exercise
fatigue
exctiability

abstract: The purpose of this investigation was to examine the effects of selective and non-selective β-blockade on muscle excitability and fatiguability during exercise. Ten healthy males (x̄ age= 21.9 ± 7.1 yrs) participated in all phases of the study. The first stage was designed to determine equipotent doses of the selective (metoprolol) and non-selective (propranolol) β-blocking agents within each subject. Symptom limited, maximal graded exercise tests were performed on an electrically braked cycle ergometer during a control condition and after the administration of 100 mg of metoprolol. Following this, exercise tests were performed to establish a dose of propranolol equipotent to that of 100 mg of metoprolol within each subject. In 8 of the subjects, 80 mg of propranolol produced a heart rate attenuation equal to that of 100 mg of metoprolol. In contrast, 1 subject required 60 mg of propranolol while another required 100 mg of propranolol to match the effects of the metoprolol treatment. Significant reductions in the submaximal and maximal oxygen uptakes were observed during the metoprolol (9% ↓ ± 7%; 10% ↓ ± 4%, respectively) and the propranolol (9% ↓ ± 7%; 19% ↓ ± 4%, respectively) treatments. Similarly, the time to exhaustion was reduced significantly by 13% (± 8%) and 19% (± 8%) following the administration of metoprolol and propranolol, respectively. The reductions in the maximal oxygen uptake and the time to exhaustion elicited by the β-blocking agents were significantly greater following the non -selective versus the selective drug treatments. It was hypothesized that part of the impairment in exercise performance with β-blockade could be the result of an inhibition in the activity of the adrenergically cor,trolled Na⁺-K⁺ ATPase with a subsequent failure in muscle excitability during exercise. Thus, in the second stage of this investigation, a double blind design was utilized to investigate the effects of metoprolol and propranolol on muscle excitability and fatiguability. Subjects performed a 4 minute fatigue protocol consisting of intermittent, isometric voluntary contractions of the knee extensor muscles in one leg. The protocols were performed on three separate occasions following the administration of either placebo, 100 mg of metoprolol or an equipotent dose of propranolol. Surface electrodes were used to record the voluntary EMG activity and M-waves from the vastus medialis in the active and inactive legs throughout each of the drug trials. During the control trial, significant declines in the evoked twitch torque (77% ↓ ± 15%) and the voluntary torque (55% ↓ ± 11%) were observed but these recovered completely within 15 minutes following the exercise. In contrast, both the voluntary EMG activity and the M-waves recorded from the active and inactive legs were maintained throughout fatigue and recovery in the control state. Neither the evoked contractile properties for the voluntary muscle strength of the knee extensors were affected by the administration of metoprolol or propranolol. The fatiguability of the quadriceps was also unaffected by the β-blocking agents. Similarly, the β-blockade treatments did not alter the EMG activity or the M-waves measured from either of the legs at rest and over the course of fatigue and recovery. The results of this investigation suggest that although β-blocking agents do impair dynamic exercise performance, there is no effect of these agents on peripheral skeletal muscle function during single limb exercise. These observations have been explained in relation to the possible central and hemodynamic effects of β-blockade.

abstract: Thesis

abstract: Master of Science (MSc)