VictorJuiz/thesis huggingface dataset:
G-Protein Coupled Receptor Mediated Metaplasticity at the Hippocampal CA1 Synapse

Activity of the NMDA receptor is crucial for CA1 plasticity. Functional modification of the receptor is one way to modulate synaptic plasticity and affect hippocampus dependent behaviours. Two GPCRs, the dopamine receptor D1 and the PACAP38 receptor PAC1, have been shown to enhance NMDA activity via Gq and Gs signaling pathways respectively. Enhancement of NMDAR activity by the D1/Gs pathway depends on phosphorylation of the NR2B subunit by Fyn kinase. Conversely, enhancement by the PAC1/Gq pathway depends on phosphorylation of the NR2A subunit by Src kinase. SKF81297, a D1 agonist, was shown to enhance LTD whereas PACAP38, through the PAC1 pathway, was shown to lower the threshold for LTP. Both effects were blocked by specific antagonists and shown to be dependent on NR2 subunit phosphorylation. Ultimately, physiological metaplasticity at the CA1 synapse may be mediated by the relative activation of many GPCR signaling pathways via modification of the NR2 subunit.

Keywords: Metaplasticity
GPCR
CA1
NMDA receptor
LTP
PACAP
Advisor: MacDonald, John F.
Hyolaryngeal Excursion as the Physiological Source of Accelerometry Signals during Swallowing

Swallowing dysfunction, or dysphagia, can result from any structural or neurological impairment that affects the swallowing mechanism. Accelerometry is a non-invasive technique that may be used to measure the epidermal vibration signals on a patient’s throat during swallowing. The purpose of this study was to map out the trajectories of the hyoid bone and arytenoids during swallowing to determine if a relationship exists between their trajectories and the signals obtained from an accelerometer placed on a participant’s neck during a scheduled videofluoroscopic swallowing study. Participants included 43 adult patients with neurogenic dysphagia. A software program was created to track the desired anatomy on the videofluoroscopic videos frame-by-frame. The data from the software was then compared to the integrated acceleration data multiple linear regression. The results show that the hyoid and larynx are not always correlated during swallowing and further suggest hyolaryngeal excursion as the primary physiological source of accelerometry.

Keywords: hyolaryngeal excursion
swallowing
accelerometry
Advisor: Chau, Tom
Steele, Catriona
Osteocytes as Mechanosensory Cells: from Extracellular Structure to Intracellular Signals

Osteocytes have been proposed as the mechanosensory cells during the process of bone adaption. In this thesis, a microfluidics chamber system (MCS) device was designed, fabricated and tested as a means to maximally simulate the in vivo osteocytic ultrastructure and reproduce the in vivo shear stress experienced by osteocyte, providing an ideal platform for in vitro study on osteocyte mechanotransduction. By employing a micropipette aspiration technique, single osteocyte adhesion and osteocytic process formation were achieved on PDMS with MCS structure. In this study, the involvement of sphingosine-1-phosphate (S1P) signaling pathway in osteocytes responding to oscillatory fluid flow (OFF) was also examined. Firstly, MLO-Y4 osteocytes like cells were demonstrated to express integrated and functional S1P cascade. By modulating S1P cascade components and testing a series of cellular outcomes, it was indicated that exogenous S1P, endogenous S1P and S1P receptor S1P2 were involved in the regulation of loading induced osteocytic responses.

Keywords: Osteocytes
Mechanotransduction
Lacuno-Canaliculi
Sphingosine-1-Phosphate
Advisor: You, Lidan
Carbon Dynamics in Canada's Managed Forests from 1991 to 2006: A Comparison of InTEC and CBM

This study examined the annual C balance and its shifting trend in Canada’s managed forests from 1991 to 2006 using the Integrated Terrestrial Ecosystem C-budget (InTEC) model. During this period, Canada’s managed forests remained a moderate C sink of 58 Mt C yr¬¬¬-1 on average, but displayed an apparent trend of shifting towards a C source. The combined risk of climate change and increased disturbances are weakening the C sink in Canada’s managed forests. This study also compared the results from InTEC with those from CBM-CFS (Carbon Budget Model of the Canadian Forest Sector) at both national and regional levels. InTEC shows larger inter-annual variability and regional difference than CBM-CFS due to its incorporation of both disturbance and non-disturbance factors. In comparison, CBM-CFS3 has likely underestimated both the true C loss and the C sink potential of Canada’s managed forests, given that it does not account for the non-disturbance factors.

Keywords: Carbon modelling
Climate change
CBM
Forest carbon dynamics
InTEC
Canada's managed forests
Advisor: Chen, Jing Ming
Designing an Optimal Urban Community Mix for an Aquifer Thermal Energy Storage System

This research examined what mix of building types result in the most efficient use of a technology known as Aquifer Thermal Energy Storage (ATES). Hourly energy simulation models for six different building archetypes were created based on representative building characteristic and energy use data from the Toronto area. A genetic algorithm optimization tool was then created to vary scheduling and production properties of the ATES system and the relative number of different building archetypes. The tool found that a cooling season from weeks 16‐42 maximized the useful energy output of the ATES and resulted in roughly 30% reduction in heating and cooling energy use and associated GHG emissions. It was also found that creating a mix consisting of a higher percentage of larger buildings than is currently found in most neighbourhoods could reduce energy usage by an additional 10%.

Keywords: Thermal Energy Storage
Aquifer
Community Mix Optimization
Energy Simulation
Advisor: Kennedy, Christopher A.
Sustainability Oriented Feasibility Model for Construction Decision Making: Water Recycling Cases in Buildings

Traditionally, feasibility analysis in the construction sector is limited to financial considerations. As the concept of sustainability becomes increasingly important, the methods used in a feasibility analysis have to be reconfigured in a way that incorporates elements of sustainability. This research uses water recycling systems (within the built environment) as an example to demonstrate how sustainability factors can be integrated quantitatively in feasibility studies. The model is structured in a triple-bottom-line framework, which consists of economic, environmental, and social aspects. Each aspect is measured by a spectrum of parameters, which evaluate three project outcomes of water recycling systems—water savings, project requirements, and positive image. Based on the quantified parameters, Green Factor, a decision making method, is formulated to assist in sustainability oriented feasibility analysis for construction projects.

Keywords: Decision making
Sustainability
Advisor: EI-Diraby, Tamer
Metakaolin Effects on Concrete Durability

Partial replacement of cement by metakaolin is known to improve concrete durability, by refining the pore structure to improve fluid transport properties and by reducing the alkalinity of the pore solution to make ASR less problematic. A gap exists in the literature as to the salt scaling performance and magnesium sulphate performance of metakaolin concrete. 10 concrete mixes were cast at w/cm ratios of 0.4 and 0.5. In addition to metakaolin, grade 80 slag was used as well as CSA GU cement. All replacement levels were tested for setting properties, compressive strength, drying shrinkage, sulphate resistance, salt scaling, ASR mitigation and chloride diffusion characteristics according to the appropriate CSA and ASTM standards. It was found that metakaolin showed better performance in magnesium sulphate solutions than slag and that metakaolin concretes attained strength and other durability properties much faster than mixes without it. Keywords: metakaolin, ASR, sulphate, magnesium, scaling, setting, diffusion

Keywords: Metakaolin
Sulphate Attack
Chloride
ASR
Advisor: Hooton, Robert Douglas
The Agency Model and Corporate Governance in China: In the Context of Privately-owned Enterprises Transformed to Public Corporations

In the context of transition, where the Chinese enterprises are seeking good models for the corporate governance, one Anglo-American corporate governance model, the agency model, seems to shed some light on enterprises that used to be privately-owned and have transformed into public corporations. Although the agency model might be a solution to the public corporations, it never the less fails to match the Chinese context in many respects. In light of the nature of the agency model and potential mismatches with the Chinese context, this thesis examines theoretical reasons that could account for the discrepancies between the two. It is argued that, despite the foreign nature of this model and the need for amendment, the Chinese public corporations are still be able to establish good corporate governance structure via it.

Keywords: law
corporate governance
China
Advisor: Ho, Betty
Towards Sustainable Development: Chinese Environmental Law Enforcement Mechanism Research

Environmental degradation is one of the most important problems facing by Chinese people. This unsatisfactory situation majorly lies in the weak implementation of environmental laws. The essential reason causing the ineffective enforcement of Chinese environmental law is people’s distorted cognition about the relation between human being and the environment. As an important principle of international environmental law, the sustainable development principle emphasizes intra-generational and intergenerational equality, aiming to realize a balance of environmental interest and socie-economic interest, which could become the guideline of the reformation of Chinese environmental law enforcement mechanism. At last, this paper analyzes the solutions to appeared problems, which are underpinned by the sustainable development principle. The ultimate purpose is to promote rational policies and responsible conducts of governments, to foster enterprises’ voluntary compliance with environmental law and to foster citizens’ environmental awareness.

Keywords: Chinese environmental law
Sustainable development principle
Advisor: Ho, Betty
How to Say You Are Sorry: A Guide to the Background and Risks of Apology Legislation

This thesis examines legislation that creates a “safe habour” for apologies by making them inadmissible as evidence of liability in a civil action. In recent years, jurisdictions across North America and Australia have enacted such “apology legislation” in an effort to encourage apologies. This is allegedly done to assist victims, who often benefit from full and sincere apologies. Legislators are also motivated, however, by the perception that apologies can induce victims to settle or forgo legal action, thereby reducing litigation rates. Whether such a correlation exists, particularly for apologies given under apology legislation, has not been firmly established, and attempting to use apologies in this manner may prove harmful to victims and the state. Apologies are powerful, and if legislators are not careful, they may enact legislation that alters apologies so that they become a source of harm to victims, the legal system, and even society as a whole.

Keywords: Apology Legislation
Benefits and risks of apologies
Admissibility of apologies
Apologies and the law
Advisor: Marrus, Michael
Potassium Changing from Pro- to Anti-convulsant in the Epileptic Juvenile Rat Hippocampus

Elevations in extracellular potassium (K+e) accompany seizure-like events (SLEs), but elevated K+ may also participate in seizure cessation. The objective of this thesis was to investigate the possibility that K+ may undergo a pro- to anti-convulsant switch in the epileptic juvenile (postnatal day 17-21) rat hippocampus. Field recordings were performed in the CA1 pyramidal layer. SLEs and primary afterdischarges (PADs) were induced with 0.25 mM Mg/5 mM K+ perfusion or tetanic stimulation of the Schaffer collaterals respectively. In these seizure models, elevating [K+]e beyond 7.5 mM showed anticonvulsant properties. The addition of ZD7288, a blocker of the hyperpolarization activated nonspecific cationic current (Ih) and allowed SLEs to continue even in elevated [K+]e. This suggests that [K+]e switches from being pro- to anti-convulsant, in part due to an elevated [K+]e-induced potentiation of Ih. Ih likely contributes to this anticonvulsant behavior by decreasing membrane resistance and subsequently attenuating summation of incoming EPSPs.

Keywords: Potassium
Epilepsy
Seizure
Hippocampus
Ih
Advisor: Carlen, Peter Louis
Mitochondria-penetrating Peptides: Characterization and Cargo Delivery

A class of mitochondria-penetrating peptides (MPPs) was studied in an effort to optimize their applications in the delivery of bioactive cargo to this therapeutically important organelle. The sequence requirements for mitochondrial entry were monitored, and it was discovered that while an alternating cationic/hydrophobic residue motif is not required, the inclusion of a stretch of adjacent cationic amino acids can impede access to the organelle. In addition, a variety of C-terminal cargos were tested to determine if there are limitations to the lipophilicity, charge, or polarity of compounds that can be transported to mitochondria by MPPs. Furthermore, these systematic studies aided the design and synthesis of a copper-binding MPP for the delivery of copper ions to mitochondria for the potential rescue of disorders associated with copper-deficiency. The results reported demonstrate that MPPs are versatile transporters that may have a wide range of biological applications.

Keywords: mitochondria
peptide transporter
drug delivery
copper delivery
Advisor: Kelley, Shana O.
Early Aerobic Exercise Intervention After Stroke: Improving Aerobic and Walking Capacity

The benefits of brief-duration, early exercise programs in stroke have been shown, but the effects of longer-duration aerobic training early after stroke have not been examined. The purpose of this study was to determine the effects of an early aerobic exercise program that extended beyond inpatient into outpatient rehabilitation on aerobic capacity, walking parameters (walking distance, speed, and symmetry), health-related quality of life, and balance. Patients in the subacute phase after stroke (n = 15) with mild to moderate impairment received aerobic exercise in addition to conventional rehabilitation. The study participants demonstrated significant improvement in aerobic and walking capacity, peak work rate, quality of life, balance, and gait velocity from baseline to midpoint. However, no difference was found between midpoint and final. This early aerobic exercise program following stroke significantly improved aerobic capacity, walking ability, quality of life and balance during the inpatient period although no further improvement was observed during the outpatient period.

Keywords: Subacute Stroke
Aerobic exercise
Rehabilitation
Walking capacity
Aerobic capacity
Advisor: Brooks, Dina
Enhancement of Critical Care Response Teams Through the Use of Electronic Nursing-mediated Vital Signs Surveillance

Failure to recognize changes in a patient’s clinical condition is a barrier to the effectiveness of CCRT outreach programs. The development of a vital signs capture and decision system could alert care providers and CCRTs when a patient’s clinical condition deteriorates. However, point-of-care vital signs capture and documentation is often problematic in clinical practice. Ethnographic research was conducted to understand the difficulties of replacing pen and paper charts and barriers to electronic nursing documentation systems. Analysis of workflows directed the design of two solutions; 1) Apple iPhone facilitated manual vital signs entry, 2) Motorola MC55 enabled automatic data capturing from physiological monitors. Nurses participated in high-fidelity usability testing, comparing the traditional method of paper documentation with the two electronic solutions. As a result of user-centered design process, both solutions were comparable to the efficiency of paper methods, were found acceptable to nurses, and could be successfully incorporated into current workflows.

Keywords: User-centered design
Vital Signs
Human Factors
Critical Care Response Teams
Advisor: Cafazzo, Joseph
Connection between Severe Weather and Intense Lightning

This Thesis researches, explains and provides conclusions for the question of correlation between data and criteria used by Environment Canada (EC) and Lightning Studies Research Group (LSG) of University of Toronto. The necessity of such correlation arises from the question of common criteria between severe weather, as it shown in graphical data from EC, and intense lighting storms, recorded by LSG, despite deep differences in area, time scale and object of observation used by those two organizations. The objective of the Thesis is not only to compare those two, very different sets of data and criteria and find out the common ground between them, but also to provide in-depth explanation of criteria, used by Lighting Studies Research Group, along with revisiting and establishing some of them. Eight storm cases, taken from years 2005-2008 provide cases for practical research, which affects intermediate Greater Toronto Area.

Keywords: lightning, storm, intense, lightning studies, lightning studies research group, charge, ECHOTOP, CAPPI, severe, non-severe, environment, CN Tower, weather, correlation
Advisor: Janischewskyj, Wasyl
Characterization of a Biodegradable Electrospun Polyurethane Nanofiber Scaffold Suitable for Annulus Fibrosus Tissue Engineering

The current study characterizes the mechanical and biodegradation properties of a polycarbonate polyurethane (PU) electrospun nanofiber scaffold intended for use in the growth of a tissue engineered annulus fibrosus (AF) intervertebral disc component. Both the tensile strength and initial modulus of aligned scaffolds were higher than those of random scaffolds and remained unaffected during a 4 week biodegradation study, suggesting a surface-mediated degradation mechanism. The resulting degradation products were non-toxic. Confined compressive mechanical force of 1kPa, was applied at 1Hz to in vitro bovine AF tissue grown on the scaffolds to investigate the influence of mechanical force on AF tissue production, which was found to decrease significantly at 72 hours relative to 24 hours, independent of any effects from mechanical forces. Overall, the consistent rate of PU degradation, along with mechanical properties comparable to those of native AF tissue, and the absence of cytotoxic effects, make this polymer suitable for further investigation for use in tissue-engineering the AF.

Keywords: intervertebral disc
annulus fibrosus
mechanical stimulation
biodegradation
tissue engineering
scaffold
nanofiber
degenerative disc
tissue engineering
Advisor: Santerre, J. Paul
Kandel, Rita A.
Inclusion Characterization in High Strength Low Alloy Steel

The cleanliness of high strength low alloy (HSLA) steel was assessed qualitatively and quantitatively. The determination of inclusion type and inclusion morphology were carried out using Selective Potentiostatic Etching by Electrolytic Dissolution (SPEED) method allowing in-situ examination of inclusion morphology by analytical techniques such as SEM/EDS. Inclusion size analysis mainly involved a combination of an analytical technique to provide images of the sample surface and an image analysis system to accurately measure the inclusion size. Four analytical methods were compared in order to evaluate their suitability for subsequent quantitative analysis. It was found that images taken with backscattered electron imaging mode from the scanning electron microscope provides the most accurate representation of inclusion distribution. The various techniques were used to evaluate HSLA steel grades of similar chemistry produced with and without gas shrouding. The results confirmed that with reoxidation minimized by gas shrouding between ladle and tundish, the steel cleanliness was significantly improved.

Keywords: Steel Cleanliness
Non-metallic Inclusions
Advisor: McLean, Alexander
On the Design of Peer-assisted Video-on-demand Systems

Peer-assisted Video-on-Demand (VoD) systems have not only received substantial recent research attention, but also been implemented and deployed with success in large-scale real-world streaming systems. Despite the remarkable popularity in real-world systems, the design of such systems are not well understood. In this thesis, we seek to address two design problems in peer-assisted VoD systems. First, we focus on the design of cache replacement algorithms. We construct an analytical framework based on dynamic programming, to help us form an in-depth understanding of optimal strategies to design cache replacement algorithms. Second, we shift our attention to the surplus upload bandwidth allocation problem in multi-channel systems. Through theoretical analysis and realistic simulations, we conclude that surplus upload bandwidth from peers can be utilized more efficiently than conventional prefetching strategies when it is devoted to redistributing content to those channels in deficit state.

Keywords: Peer-to-Peer
Video-on-Demand
Optimization
Advisor: Li, Baochun
Coherent Shared Memories for FPGAs

To build a shared-memory programming model for FPGAs, a fast and highly parallel method of accessing the shared-memory is required. This thesis presents a first look at how to implement a coherent caching system in an FPGA. The coherent caching system consists of multiple distributed caches that implement the write-once coherence protocol, allowing efficient access to system memory while simplifying the user programming model. Several test applications are used to verify functionality, and assess performance of the current system. Results show that with a processor-based system, some applications could benefit from improvements to the coherence system, but for many applications, the current system is sufficient. However, the current coherent caching system is not sufficient for most hardware core based systems, because the faster memory accesses quickly saturate shared system resources. As well, the performance of distributed-memory systems currently surpasses that of the coherent caching system. Performance results are promising, and given the potential for improvements, future work on this system is warranted.

Keywords: FPGA
Computer Engineering
Caching
Shared Memory
Advisor: Chow, Paul
Investigation of the Relationship between Transit Network Structure and the Network Effect - The Toronto & Melbourne Experience

The main objective of this study was to quantitatively explore the connection between network structure and network effect and its impact on transit usage as seen through the real-world experience of the Toronto and Melbourne transit systems. In this study, the comparison of ridership/capita and mode split data showed that Toronto’s TTC has better performance for the annual data of 1999/2001 and 2006. After systematically investigating travel behaviour, mode choice factors and the various evidence of the network effect, it was found that certain socio-economic, demographic, trip and other design factors in combination with the network effect influence the better transit patronage in Toronto over Melbourne. Overall, this comparative study identified differences that are possible explanatory variables for Toronto’s better transit usage as well as areas where these two cities and their transit systems could learn from one another for both short and long term transit planning and design.

Keywords: Public Transit Planning
Transit Network
Advisor: Shalaby, Amer Saïd