VictorJuiz/thesis huggingface dataset:
Interactive Effects of Hypoxia and Cocaine Treatment on Ventilatory Chemoreflexes and Locomotor Sensitisation

This study investigated two hypotheses. First, that chronic cocaine treatment would mimic the changes in breathing that are associated with ventilatory acclimatisation to chronic hypoxia (VAH). Second, that pre-treatment with a hypoxic stressor would bring about cross-sensitisation to cocaine. To address the first hypothesis, rats were exposed to either chronically hypoxic or chronically normoxic conditions and treated with either cocaine or saline for a 14 day period. Following this period, acute breathing trials were performed to measure resting ventilation and ventilatory chemoreflexes. The results demonstrated that chronic cocaine treatment did not induce the changes in breathing associated with VAH. To address the second hypothesis rats were exposed to a hypoxic stressor for 10 days (either intermittent hypoxia or chronic hypoxia) after which cocaine sensitisation was measured via locomotor sensitisation trials. The results demonstrated that cross-sensitisation between a hypoxic stress and cocaine was observed for intermittent but not chronic hypoxia.

Keywords: hypoxia
cocaine
ventilatory acclimatisation to hypoxia
ventilatory chemoreflexes
locomotor sensitisation
Advisor: Reid, Stephen G.
Erb, Suzanne
Defining a Model of Classical Activation in Microglia

Microglia, the resident immune cells of the central nervous system, can become activated following injury, disease, or infection. In vitro, they can be activated by stimuli, which determine the inflammatory phenotype they will develop. In this thesis, stimulating microglia with tumor necrosis factor- and interferon- resulted in classical activation, characterized by proliferation, increased transcription of complement receptor 3 and major histocompatibility class II molecules, and elevated production and transcription of interleukin-1 and nitric oxide. Stimulation with TNF and IFN also changed the intensity of phosphorylated (activated) cyclic adenosine monophosphate response element binding protein immunoreactivity in microglia. Specifically, cells differentiated into populations with high or low pCREB intensity. This was the first example of such a response in microglia and was representative of what occurred in vivo, after ICH. Thus, the characterization of this model will be useful for future studies of this and other intracellular pathways of classically activated microglia.

Keywords: Neuroinflammation
Microglia
Cytokine
cAMP Response Element Binding Protein
Advisor: Schlichter, Lyanne C.
Antisaccades: A Probe into the Dorsolateral Prefrontal Cortex in Alzheimer's Disease

The number of people living with Alzheimer’s Disease (AD) is projected to increase dramatically over the next few decades, making the search for treatments and tools to measure the progression of AD increasingly urgent. The antisaccade task, a hands- and language-free metric, may provide a functional index of the Dorsolateral Prefrontal Cortex (DLPFC), which is damaged in the later stages of AD. Patients with AD make significantly more antisaccade errors than controls, however, performance in mild AD has remained unexplored. We hypothesized that mild patients will make more errors than controls. Thirty AD patients and 31 age-match controls completed both laptop-based and clinical versions of the antisaccade task. Two thirds of patients with AD made significantly more errors and corrected less of their errors than age-matched controls. Our findings indicate that antisaccade impairments exist in mild AD, suggesting DLPFC pathology may be present earlier than suggested by previous studies.

Keywords: Antisaccades
Alzheimer's Disease
Advisor: Black, Sandra
Searching for Radiosensitizers: Development of a Novel Assay and High-throughput Screening

The colony formation assay (CFA) is the gold standard for measuring cytotoxic effects on cells. To increase efficiency, the CFA was converted to a 96-well format using an automated colony counting algorithm. The 96-well CFA was validated using ionizing radiation (IR) on the FaDu and A549 cancer cell lines. Its ability to evaluate combination therapies was investigated using cisplatin and IR. The 96-well CFA was transferred to a robotic platform for evaluation as a high-throughput screen (HTS) readout for the discovery of novel anti-cancer compounds, and radiosensitizers. Screening yielded eight putative anti-cancer hits, and five putative radiosensitizing hits. Secondary screening confirmed 6/8 anti-cancer compounds, and 0/5 radiosensitizing compounds. Thus, the 96-well CFA can be adopted as an alternative assay to the 6-well CFA in the evaluation of cytotoxicity in vitro, providing a possible readout to be utilized in HTS for discovering anti-cancer compounds, but with limited applicability in discovering radiosensitizers.

Keywords: Radiosensitizer
High-Throughput Screening
Colony Formation Assay
Advisor: Liu, Fei-Fei
Space for Healthy Communities: An Exploration of the Social Pathways between Public Space and Health

This thesis investigates the relationship between access to public gathering spaces and self-reported health with indicators of community life as the intervening variables. This study was undertaken to investigate the relationship between the access to public space and self-rated health status in multicultural communities. A survey of 785 randomly-selected households was conducted across four low-income Toronto neighbourhoods. The investigation is framed by the 'production of healthy public space' model, which conceptualizes the pathways between the lived experience of space and health as impacting an individual’s likelihood of establishing place attachment. The results support the hypothesis that there is a relationship between the lived dimension of space and health. Mental health appears to be the outcome most affected by indicators of place attachment. Several of the aforementioned relationships were found more commonly in the densest of the four neighbourhoods and variations were found between foreign- and Canadian-born subpopulations.

Keywords: public space
place attachment
place-based identity
neighbourhood health
Advisor: Dunn, James
Design of an Adaptive System for Upper-limb Stroke Rehabilitation

Stroke is the primary cause of adult disability. To support this large population in recovery, robotic technologies are being developed to assist in the delivery of rehabilitation. A partially observable Markov decision process (POMDP) system was designed for a rehabilitation robotic device that guides stroke patients through an upper-limb reaching task. The performance of the POMDP system was evaluated by comparing the decisions made by the POMDP system with those of a human therapist. Overall, the therapist agreed with the POMDP decisions approximately 65% of the time. The therapist thought the POMDP decisions were believable and could envision this system being used in both the clinic and home. The patient would use this system as the primary method of rehabilitation. Limitations of the current system have been identified which require improvement in future research stages. This research has shown that POMDPs have promising potential to facilitate upper extremity rehabilitation.

Keywords: rehabilitation
robotics
artificial intelligence
POMDP
stroke
upper-limb
Advisor: Mihailidis, Alex
The Relationship Between Adult Hippocampal Neurogenesis and Spatial Learning and Memory in Natural Populations of Food-storing Red Squirrels (Tamiasciurus hudsonicus).

Previous research on the relationship between spatial memory and adult hippocampal neurogenesis has been controversial. In the present study, neurogenesis was compared between two natural populations of the same species that differ in their reliance on spatial memory to cache and retrieve stored food. Western red squirrels store food in a single site whereas eastern red squirrels store food in multiple sites. Neurogenesis was assessed using endogenous markers of the number of proliferating cells (Ki-67) and the number of immature neurons (DCX), and neuronal recruitment was determined by measuring the area of the dentate gyrus of the hippocampus. The number of proliferating cells, immature neurons and neuronal recruitment were enhanced in the eastern compared to the western red squirrels, reflecting the food storing strategies used by the squirrels. This suggests that there is a positive correlation between adult hippocampal neurogenesis and spatial learning and memory.

Keywords: adult neurogenesis
hippocampus
dentate gyrus
spatial learning and memory
red squirrels
food-storing
immunohistochemistry
Ki-67
DCX
NeuN
Advisor: Wojtowicz, Jan Martin
Boonstra, Rudy
Designing a Matrix Metalloproteinase-7-activated Quantum Dot Nanobeacon for Cancer Detection Imaging

Quantum Dot (QD) nanobeacons distinguish themselves from molecular beacons with the promise of non-linear activation, tunability, and multi-functionality. These unique features make them highly attractive for cancer detection imaging with opportunities for increased signal-to-background ratio and tunable sensitivity. In this thesis, a nanobeacon was designed to target matrix metalloproteinase-7 (MMP-7), known to be over-expressed by a wide array of tumours. The nanobeacon is normally dark until specifically activated by MMP-7. The overall design strategy links single QDs to multiple energy acceptors by GPLGLARK peptides that can be cleaved specifically by MMP-7. However, design details such as the choice of energy acceptor and conjugation method was found to drastically alter the function of the nanobeacon. Studies of nanobeacons synthesized with Black Hole Quencher-1 or Rhodamine Red by either covalent conjugation or electrostatic self-assembly revealed that peptide conformation and bonding flexibility are both important considerations in nanobeacon design due to QD sterics.

Keywords: Quantum dot
Matrix metalloproteinase
Cancer detection
Optical imaging
Protease sensor
Nanotechnology
Advisor: Chan, Warren C. W.
Zheng, Gang
Fluid Coke Derived Activated Carbon as Electrode Material for Electrochemical double Layer Capacitor

An electrochemical double-layer capacitor (EDLC) is a potential buffer for current power and energy supply. In this work, activated carbon derived from fluid coke as a brand new electrode material was studied due to its high specific surface area (SSA) and large portion of mesopores. A suitable electrode material formula, current collector, and cell configuration were investigated to fabricate a testable system and ensure the reproducibility of measurements. Cyclic voltammetry (CV) and constant current charge/discharge (CD) techniques were used to characterize the performance of the electrode material, as well as to study its fundamental behaviour. A new procedure was established for quantifying the capacitance (Cc) of EDLC from CV which isolates the effect of internal resistance on the measured capacitance (CM). The specific capacitance of single electrode made of activated carbon (~1900 m2/g) with approximately 80% mesopores and macropores was able to reach 180 F/g at scan rate of 0.5mV/s.

Keywords: fluid coke
activated carbon
electrochemical double layer capacitor
capacitance
cyclic voltammetry
constant current charge/discharge
Advisor: Jia, Charles Q.
Kirk, Donald W.
Wang An Shi and the Balance of Form and Function

The reform-minded aspect of Wang's writing is frequently emphasized while its rhetorical component is overlooked. Similarly, in texts which appear poetic in nature the underlying subject matter of reform fails to be recognized. Both rhetoric and its antithesis function in tandem in all of Wang's texts, the one serving to balance the other; stylistic writing serves to soften political discourse. When Wang writes poetically, the problem of reform is served through allusion. In contrast, when direct terminology is employed, this is balanced by rhetorical analogy (often citing the past to prove the present, jie gu yu jin). Because his subject matter is predominantly political, Wang's memorials and prose texts are well known, while his poetry has remained in relative obscurity. Nevertheless, even the memorials rely on the balance of rhetoric and aesthetics, which he describes in his best known text "Shang Ren Zong Huang Di Yan Shi Shu".

Keywords: Wang Anshi
Song ci
Advisor: Sanders, Graham
On the Generation of Subthreshold Membrane Potential Fluctuations in Hippocampal CA1 Interneurons

A class of hippocampal interneurons in CA1, bordering the lacunosum-moleculare and radiatum hippocampal layers (the LM/R cell), has been shown to exhibit membrane potential oscillations (MPOs) subthreshold to action potential generation. MPOs occur at theta frequency (4-12 Hz) and are of interest because of their putative role in promoting network level theta activity. MPOs arise without synaptic input suggesting that they originate through interactions in the cell’s repertoire of currents. To investigate the generation of MPOs we develop a single compartment model of the cell based on the physiological characterization of its currents. The model includes both deterministic current models and white noise. Our analysis allows for a complete characterization of the cell’s dynamics over the subthreshold range and shows that MPOs arise through the interaction between current dynamics and system noise. We find that MPOs show a particular dependency on the A-type potassium and persistent sodium current magnitudes.

Keywords: hippocampus
theta frequency oscillations
Advisor: Skinner, Frances
Reliable Broadcast of Safety Messages in Vehicular Ad hoc Networks

Broadcast communications is critically important in vehicular networks. Many safety applications need safety warning messages to be broadcast to all vehicles present in an area. In this thesis, we propose a novel repetition-based broadcast protocol based on ``optical orthogonal codes.'' Optical orthogonal codes are used because of their ability to reduce the possibility of collision. We present a detailed mathematical analysis for obtaining the probability of success and the average delay. Furthermore, we propose to use coding to increase network throughput, and ``adaptive elimination'' of potentially colliding transmissions to further increase reliability. We show, by analysis and simulations, that the proposed protocol outperforms existing repetition-based ones and provides reliable broadcast communications and can reliably deliver safety messages under load conditions deemed to be common in vehicular environments. We also show that the proposed protocol is able to provide different levels of quality of service.

Keywords: Communication networks
Wireless ad hoc networks
vehicular commuincations
vehicular safety systems
Advisor: Valaee, Shahrokh
Investigating the Correlation between Swallow Accelerometry Signal Parameters and Anthropometric and Demographic Characteristics of Healthy Adults

Thesis studied correlations between swallowing accelerometry parameters and anthropometrics in 50 healthy participants. Anthropometrics include: age, gender, weight, height, body fat percent, neck circumference and mandibular length. Dual-axis swallowing signals, from a biaxial accelerometer were obtained for 5-saliva and 10-water (5-wet and 5-wet chin-tuck) swallows per participant. Two patient-independent automatic segmentation algorithms using discrete wavelet transforms of swallowing sequences segmented: 1) saliva/wet swallows and 2) wet chin-tuck swallows. Extraction of swallows hinged on dynamic thresholding based on signal statistics. Canonical correlation analysis was performed on sets of anthropometric and swallowing signal variables including: variance, skewness, kurtosis, autocorrelation decay time, energy, scale and peak-amplitude. For wet swallows, significant linear relationships were found between signal and anthropometric variables. In superior-inferior directions, correlations linked weight, age and gender to skewness and signal-memory. In anterior-posterior directions, age was correlated with kurtosis and signal-memory. No significant relationship was observed for dry and wet chin-tuck swallowing

Keywords: aspiration
accelerometry
anthropometric
canonical correlation
segmentation algorithm
Advisor: Chau, Tom
Steele, Catriona
Methodologies in Digital Watermarking: Robust and Reversible Watermarking Techniques for Authentication, Security and Privacy Protection

The advances in recording, editing and broadcasting multimedia content in digital form motivate the protection of digital information against illegal use, manipulation and distribution. This thesis work focuses on one aspect of digital rights management (DRM), namely digital watermarking. Specifically, we study its use in copy protection, tamper detection and information hiding. We introduce three application-specific digital watermarking techniques. The first two algorithms, based on embedding film grain like noise and signal dependent watermarks, respectively, are designed for authentication applications. The advantage is that they are able to detect malicious tampering while being robust against content-preserving processes such as compression, filtering and additive noise. The third method, a reversible watermarking technique, is designed so that sensitive personal information can be embedded in medical images. Simulation results show that our proposed method outperforms other approaches in the available literature in terms of image quality and computational complexity.

Keywords: Digital Watermarking
Image Authentication
Privacy Protection
Security
Advisor: Hatzinakos, Dimitrios
Integration of Non-Efficiency Objectives in Competition Law

Competition law constitutes part of broader policies. Thus, in addition to the pursuit of efficiency, competition law expresses non-efficiency concerns. The paper will explore the theoretical perspectives as to the objectives of competition law; analyze the practical aspects that implementation of non-efficiency objectives entail; and suggest a framework for implementation of non-efficiency objectives within competition law. As will be argued, non-efficiency objectives should – to varying degrees along the axes of time, place and circumstances - play a meaningful role in competition analysis. The primary assertion of the paper will be that competition law ought to consistently strive to outline the contours of those axes. Such contours should be drawn primarily on the basis of the potential adverse effects of the restrictive trade practice upon efficiency, as compared to the potential public benefit that may stem from the practice, as well as upon the circumstances that prevail within the jurisdiction.

Keywords: competition law
Advisor: Katz, Ariel
Evaluation of a pGLcNAc-derived Material as an Activator of Intervertebral Disc Tissue Repair

Degeneration of the intervertebral discs is the most common cause of back pain. The early stages of degeneration affect the nucleus pulposus (NP) of the intervertebral discs followed by a rapid degeneration of the annulus fibrosus. Regeneration of the NP may slow down or reverse the progression of the disease. A new deacetylated derivative of a marine diatomic glycosaminoglycan was developed to obtain a hydrogel formulation proposed to have a reparative effect on damaged NP tissue. The hydration kinetics and viscoelastic behaviour of the hydrogel under shear were studied and compared with the behaviour of nondegenerated human lumbar NP. In vitro studies were conducted using primary cell cultures treated with the drug to study cell viability and extracellular matrix factor expression. In vivo studies using New Zealand White (NZW) rabbits have also been conducted using MRI to quantify disc volume followed by histological and immunohistochemical analysis. Rheological data has indicated that the elastic component of the hydrogel dominates the viscous component over a frequency range of 0.1 to 15.85 rad/s. Proteoglycan expression of the treated cells was found to be 78.4 ± 1.9 (p<0.05) times higher than the untreated controls. RTPCR and immunohistochemical data from in vitro studies have demonstrated that characteristic the chondrocyte markers, aggrecan and collagen II, are expressed in the treated cells. A comparison of disc volumes at 6 weeks post-op has shown that the treated discs have 41% greater volume than the untreated iii discs (p<0.05). The results obtained in this study demonstrate that the sulfated deacetylated glycosaminoglycan derivative is a promising material to be utilized in treatment of NP degeneration.

Keywords: Biomedical
Engineering
Advisor: Whyne, Cari
Yee, Albert
Evaporation-driven, Template-assisted Nanocrystal Assembly (ETNA): A Novel Approach to Fabrication of Functional Nanocrystal Solids

Synthesis of nanocrystals is one of the most rapidly advancing areas of nanoscience, and today nanocrystals can be produced with impressive control over their composition, size, shape, polydispersity, and surface chemistry. As such, they are ideal building blocks for fabricating hierarchical architectures with tailorable functionality on every level of the hierarchy. Here an evaporation-driven, template-assisted nanocrystal assembly (ETNA) technique is developed, providing a novel and general approach to fabricating freestanding, 3D, functional architectures using diverse combinations of colloidal nanocrystal species and porous templates of arbitrary geometry. Colloidal PbS (photoluminescent) and CoFe2O4 (superparamagnetic) nanocrystals are template-assembled to fabricate freestanding nanorods and inverse opals, which retain the size-dependent properties of their constituent building blocks while replicating the geometry and preserving the functionality of the templates. Further multifunctionality is demonstrated through mixed-nanocrystal architectures which exhibit the aggregate functionality of their building blocks.

Keywords: self-assembly
plasma
nanoparticle
nanocrystal
template
hierarchy
Advisor: Ozin, Geoffrey Alan
Oral Health Policies in Toronto Daycare and Elementary Schools

This study’s objectives were to: 1. Determine the prevalence of oral care policies in daycares and elementary schools. 2. Examine the availability of resources. 3. Analyze the results by neighborhood income class. Information was collected using a questionnaire. Differences in proportion of institutions with policy, comparisons between daycares and schools, and prevalence of policies by neighborhood income class were performed. Qualitative responses were categorized and interpreted from a qualitative standpoint. Most institutions did not have a policy regarding oral hygiene. Daycares were more likely to have a policy (17% vs. 5%, p<0.001), and more likely to have sinks for toothbrushing (85% vs. 51%, p<0.001). No significant difference in policy prevalence was found among income neighborhoods. Most institutions did not have a policy regarding oral hygiene. The findings suggest that there is a need for a uniform oral care policy in educational institutions, supported by appropriate resources for its implementation.

Keywords: Oral Health
Children
Policy
Advisor: Kulkarni, Gajanan
Color Image Based Face Recognition

Traditional appearance based face recognition (FR) systems use gray scale images, however recently attention has been drawn to the use of color images. Color inputs have a larger dimensionality, which increases the computational cost, and makes the small sample size (SSS) problem in supervised FR systems more challenging. It is therefore important to determine the scenarios in which usage of color information helps the FR system. In this thesis, it was found that inclusion of chromatic information in FR systems is shown to be particularly advantageous in poor illumination conditions. In supervised systems, a color input of optimal dimensionality would improve the FR performance under SSS conditions. A fusion of decisions from individual spectral planes also helps in the SSS scenario. Finally, chromatic information is integrated into a supervised ensemble learner to address pose and illumination variations. This framework significantly boosts FR performance under a range of learning scenarios.

Keywords: Color Face Recognition
Biometrics
Small Sample Size Problem
Advisor: Plataniotis, Konstantinos N.