VictorJuiz/thesis huggingface dataset:
Limited Field-of-view Cone Beam CT Imaging of the Temporomandibular Joint: Comparative Dosimetry and Diagnostic Efficacy
Keywords: temporomandibular joint
cone beam CT
dosimetry
spatial resolution

Imaging of the osseous structures of the temporomandibular joint is best accomplished using computed tomography (CT). Cone beam CT offers a reduced radiation dose and improved spatial resolution compared to multislice helical CT. This study evaluates comparative dosimetry for temporomandibular joint imaging using two different cone beam CT systems, the Hitachi CB MercuRay and Kodak 9000 3D. These systems demonstrate differing properties with respect to field-of view sizes, operational technique factors, and spatial resolution. The Kodak 9000 3D unit offers an effective radiation dose reduction of greater than ten-fold compared with the Hitachi CB MercuRay, depending on kVp and mA. A subsequent clinical study evaluating the effect of spatial resolution on the ability to detect osseous changes related to temporomandibular joint degenerative disease found no significant difference in diagnostic efficacy between high and low spatial resolution images, however, observers consistently associated high spatial resolution with superior image quality.
Attitude Control Hardware and Software for Nanosatellites
Keywords: nanosatellites
reaction wheel
hysteresis rod
acceptance test
hardware emulation in software
attitude determination and control
attitude determination
attitude control
torque jitter

The analysis, verification and emulation of attitude control hardware for nanosatellite spacecraft is described. The overall focus is on hardware that pertains to a multitude of missions currently under development at the University of Toronto Institute for Aerospace Studies - Space Flight Laboratory. The requirements for these missions push the boundaries of what is currently the accepted performance level of attitude control hardware. These new performance envelopes demand new acceptance test methods which must verify the performance of the attitude control hardware. In particular, reaction wheel and hysteresis rod actuators are the focus. Results of acceptance testing are further employed in post spacecraft integration for hardware emulation. This provides for a reduced mission cost as a function of reduced spare hardware. The overall approach provides a method of acceptance testing to new performance envelopes with the benefit of cost reduction with hardware emulation for simulations during post integration.
Adolescents with Severe Obesity: Outcomes of Participation in an Intensive Obesity Management Program
Keywords: adolescent obesity
obesity management program
program evaluation

Objective: To evaluate the SickKids Team Obesity Management Program (STOMP), an obesity management program for severely obese adolescents. Methods: Non-randomized study of 6 and 12 month outcomes in STOMP patients vs. a comparison group of obese adolescents. Results: At 6 months, STOMP patients stabilized their BMI (0.08±0.3 kg/m2;p=0.79) and reported improved psychological and health behaviour measures, whereas comparison participants increased their BMI (0.7±0.2 kg/m2;p=0.004) and had worsening of cardiometabolic outcomes. Between-group differences included improved cardiometabolic, psychological and health behaviour measures in STOMP patients. At 12 months, STOMP patients stabilized their BMI (0.8±0.5 kg/m2;p=0.07), had improvements in anthropometric and cardiometabolic outcomes and reported an increase in health behaviours, whereas comparison participants increased their BMI (1.2±0.4 kg/m2;p=0.001) and had worsening of cardiometabolic outcomes. Between-group differences included improved anthropometric, cardiometabolic and health behaviour outcomes in STOMP patients. Conclusions: Participation in STOMP improved anthropometric, cardiometabolic, psychological and health behaviour outcomes among severely obese adolescents.
Development and Evaluation of an Online Transcranial Doppler Ultrasonographic Brain-computer Interface for Communication
Keywords: Brain computer interface
Transcranial Doppler ultrasound

We investigated an emerging brain-computer interface (BCI) modality, namely, transcranial Doppler ultrasonography (TCD), which measures cerebral blood flow velocity. We hypothesized that a bilateral TCD-driven online BCI would be able to dichotomously classify a user’s intentions with at least 70% accuracy. To test this hypothesis, we had three objectives: (1) to develop a signal classifier that yielded high (>80%) offline accuracies; (2) to develop an online TCD-BCI system with an onscreen keyboard; and, (3) to determine the achievable online accuracy with able-bodied participants. With a weighted, forward feature selection and a Naïve Bayes classifier, sensitivity and specificity of 81.44 ± 8.35% and 82.30 ± 7.39%, respectively, were achieved in the online differentiation of two mental tasks. The average information transfer rate and throughput of the system were 0.87 bits/min and 0.35 ± 0.18 characters/min, respectively. These promising online results encourage future testing of TCD-BCI systems with the target population.
Stochastic Models For Evolution Of Tumor Geometry for Cervical Cancer During Radiation Therapy
Keywords: Tumor evolution
Stochastic process
Radiation therapy
Cervical cancer

Adaptive radiation therapy re-optimizes treatment plans based on updated tumor geometries from magnetic resonance imaging scans. However, the imaging process is costly in labor and equipment. In this study, we develop a mathematical model that describes tumor evolution based on a Markov assumption. We then extend the model to predict tumor evolution with any level of information from a new patient: weekly MRI scans are used to estimate transition probabilities when available, otherwise historical MRI scans are used. In the latter case, patients in the historical data are clustered into two groups, and the model relates the new patient's behavior to the existing two groups. The models are evaluated with 33 cervical cancer patients from Princess Margaret Cancer Centre. The result indicates that our models outperform the constant volume model, which replicates the current clinical practice.
Antigen-binding Fragments: Production for and Use in Crystallographic Studies
Keywords: antigen-binding fragment
X-ray crystallography
HIV-1
broadly neutralizing monoclonal antibody

An immunoglobulin (IgG) consists of two antigen-binding fragments (Fab) connected to a crystallisable fragment through hinge regions. This thesis mainly investigates the production methods of Fabs used in structural studies. A cost effective and time saving protocol has been established for the production of recombinant 2F5 Fab, a HIV-1 broadly neutralizing monoclonal antibody fragment, using an Escherichia coli expression system. The integrity of structure and antigen-binding capability of the produced 2F5 Fab was confirmed by determining the crystal structure of the Fab-antigen peptide complex. In parallel, 3H1 Fab, a fragment of an antibody which is involved in detecting misfolded superoxide dismutase, which is related to familial amyotrophic lateral sclerosis, was produced by papain proteolysis of its parent IgG molecule. Both Fab production methods resulted in high yields of pure Fab samples that are crystallisable and ready to be engaged in structural studies using X-ray crystallography.
Controlling Early-age Transverse Cracking in High Performance Concrete Bridge Decks
Keywords: High Performance Concrete
Restrained Shrinkage Cracking

This research was undertaken to study the effects of high performance concrete (HPC) mix design modifications on the propensity of early-age cracking. Seven mixtures were tested: one 35 MPa conventional concrete (CC) mixture made with ordinary Portland cement with blended slag; one typical 50 MPa HPC mixture containing slag and silica fume; and five modified HPC mixtures using extra set-retarder, increased slag replacement, shrinkage-reducing admixture (SRA), pre-saturated lightweight aggregate (LWA), and decreased cement paste content to improve thermal and/or shrinkage properties. The mixtures were tested for durability, mechanical, thermal, and shrinkage properties. All modified HPC mixtures showed reduced shrinkage relative to the HPC control mixture, and the most shrinkage mitigation was observed in the mixture containing LWA. While SRA reduced restrained shrinkage in HPC to the magnitude of CC, it provided very low rapid chloride penetrability, and using LWA in HPC resulted in significant restrained shrinkage reduction compared to CC.
Effects of a New Conjugate Drug in a Rat Model of Postmenopausal Osteoporosis
Keywords: osteoporosis treatment
bone formation
anabolic
conjugate
OVX
ovariectomized
rat
in vivo
endocortical
prodrug
dual-acting
EP4 agonist
alendronate
intracortical remodeling
trabecular
prostaglandin E2

Postmenopausal osteoporosis is a disease characterized by bone loss and increased risk of fracture, and represents a significant burden on the Canadian health care system. Current treatments lack the ability to simultaneously address the therapeutic needs for promoting bone formation and inhibiting resorption. Our approach employs a novel conjugate drug in which an anabolic agent (EP4 receptor agonist) is reversibly joined with an anti-resorptive agent (alendronate) through a linker. This allows the bone-targeting ability of alendronate to deliver the EP4 agonist to bone sites, thereby mitigating the side effects associated with systemic administration of the EP4 agonist. This study investigated the in vivo efficacy of this drug in a curative experiment to treat postmenopausal osteoporosis using an ovariectomized rat model. Results showed that conjugate treatment dose-dependently stimulated bone formation and restored ovariectomy-induced bone loss, and conjugation between alendronate and the EP4 agonist was crucial to the drug’s anabolic effect.
The Role of BLNK in Avian B-cell Development
Keywords: B-cell development
BLNK

BLNK is an adaptor protein that functions in B-cell receptor signalling, and is vitally necessary at signalling checkpoints of mammalian B-cell development. However, its importance to avian B-cell development remains unclear. To explore the function of BLNK in chickens, shRNA-mediated RNA interference was delivered to a chicken B-cell line in vitro by replication-competent avian retrovirus (RCAS), and effective shRNA were determined. To observe an shRNA phenotype on chicken B-cell development, we simultaneously explored whether RCAS penetrance was correlated between red blood cells (RBC) and bursal B-cells by infecting chicken embryos with RCAS expressing a fluorescent tag. We found that RCAS penetrance was correlated between RBC and B-cells, which provides a system to observe any in vivo effects of BLNK shRNA on B-cell development. Furthermore, this system for observing BLNK function may be complemented by genetically-modified BLNK, particularly variants resistant to RNA interference.
Texture Analysis of Optical Coherence Tomography Speckle for the Detection of Tissue Variability
Keywords: Optical Coherence Tomography (OCT)
texture analysis
tissue characterization

About 50% of cancer patients are treated with X-ray radiation therapy; however, with current treatment feedback, the effects and the efficacy of the treatment are generally detected several weeks/months after treatment completion. This makes the adjustment of the treatment based on early response, and identification of non-responding patients, nearly impossible. In this thesis a novel method combining optical coherence tomography and a gamut of image analysis methods is explored as a potential approach to detecting tissue variability. Applying texture analysis to the optical coherence tomography images may allow for the tracking of radiation therapy induced cell microstructural changes in cancer patients and help in the adjustment of treatment based on early response.
Indoor Location-based Recommender System
Keywords: Recommender System
Indoor Localization

WiFi-based indoor localization is emerging as a new positioning technology. In this work, we present our efforts to find the best recommender system based on the indoor location tracks collected from the Bow Valley shopping mall for one week. The time a user spends in a shop is considered as an implicit preference and different mapping algorithms are proposed to map the time to a more realistic rating value. A new distribution error metric is proposed to examine the mapping algorithms. Eleven different recommender systems are built and evaluated in terms of accuracy and execution time. The Slope-One recommender system with a logarithmic mapping algorithm is finally selected with a score of 1.292, distribution error of 0.178 and execution time of 0.39 seconds for ten runs.
Sleep-wake Behaviour in Rats: The Link between Ultradian Rhythms and Sleep Homeostasis
Keywords: Ultradian Rhythms
Sleep
Rats
Sleep Homeostasis

The underlying mechanism for the origin of ultradian rhythms is not clearly understood at present. Based on a recent study from our laboratory, we have conceptualized a model for the origin of quasiperiodic ultradian rhythms in sleep-wake state. This model hypothesizes that the ultradian rhythms of sleep-wake state may be generated by a mechanism that includes the sleep-wake homeostat. The main purpose of the present study was to test the hypothesis that sleep homeostasis and sleep-wake ultradian rhythms share a common underlying mechanism. The present study has refuted that hypothesis. I conclude that: (1) the proposed model for the generation of quasiperiodic ultradian rhythms in sleep-wake state in mammals is overly simplistic in its present form, (2) the generation of ultradian rhythms in sleep-wake state probably arise from a more complex systemic interactions between the sleep-wake oscillatory network and other internal/external inputs, rather than the simple expression of sleep homeostat.
Creation of a Retroviral RNAi Knockdown System to Investigate Gene Variants in SLE
Keywords: Immunology
Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by the production of autoantibodies against self-antigens. SLE has a complex multifactorial genetic basis. Genome wide association studies (GWAS) have implicated polymorphisms causing decreased expression in many genes in SLE etiology and will likely continue to implicate new genes. Therefore, the aim of my project was to create a modular system where the effect of knocking down a gene of interest can be studied in cell culture in a timely manner. This was accomplished by inserting shRNAmirs targeting our validation gene, A20, into a retroviral vector, creating viral particles using a packaging cell line, and infecting cultured cells. Two shRNAmirs were determined to be effective by qRT-PCR and Western blots on infected cells. Vectors carrying these shRNAmirs were used to infect ex vivo B cells and BMDCs, and results suggested that A20 knockdown may mediate functional changes in both cell types.
Experimental Realization of Decoy State Polarization Encoding Measurement-device-independent Quantum Key Distribution
Keywords: Decoy State
Polarization
Measurement Device Independent
Quantum Key Distribution

Quantum key distribution (QKD) allows two remote parties to generate secret keys for cryptographic purposes. Its security has been proven with some assumptions. However, practical realizations may not comply with all the assumptions, leading to various attacks. Founded on the observation that almost all attacks are on the detection part, measurement-device-independent QKD (MDI-QKD) was proposed to remove all such attacks. This thesis presents an implementation of the protocol. In our implementation, key bit information was encoded in the polarization states of weak coherent pulses at 1542 nm wavelength in optical fibers, and decoy state techniques were employed. We ensured stable polarization preparation and alignment and developed a QKD system over 10 km of standard Telecom fibers at 500 KHz repetition rate. Our work demonstrates the practicality of MDI-QKD protocol of removing all attacks, existing and yet to be discovered, on the detection part of a QKD system.
Whether China’s State-Owned Commercial Banks Constitute “Public Bodies” within the Meaning of Article 1.1 (a) (1)
Keywords: Public Bodies
State-Owned Commercial Banks

US – Definitive Anti-dumping and Countervailing Duties on Certain Products from China is the initial WTO dispute in which China claims that US-countervailing duties on certain products from China are inconsistent with the obligations of the United States under the SCM Agreement. The meaning of “public bodies” within Article 1.1 (a) (1) of the SCM Agreement and the question of whether China’s “SOCB” constitute “public bodies” are the heart of the matter. The thesis argues that the theory of the governmental function is more persuasive than that of governmental control in terms of defining “public bodies”. Although the majority ownership of China’s SOCBs has remained in the Chinese government, their policy-oriented nature has been largely marginalized. The conclusion is that the WTO system needs to give developing countries more policy flexibility, and developing countries should also make the best use of their latent comparative advantage and the effects of globalization.
Design and Development of an Experimental Apparatus to Study Jet Fuel Coking in Small Gas Turbine Fuel Nozzles
Keywords: jet fuel
fossil fuel
thermal stability
gas turbine
coking
injector nozzle
pressure drop
engine

An experimental apparatus was designed and built to study the thermal autoxidative carbon deposition, or coking, in the fuel injection nozzles of small gas turbine engines. The apparatus is a simplified representation of an aircraft fuel system, consisting of a preheating section and a test section, which is a passage that simulates the geometry, temperatures, pressures and flow rates seen by the fuel injection nozzles. Preliminary experiments were performed to verify the functionality of the apparatus. Pressure drop across the test section was measured throughout the experiments to monitor deposit buildup, and an effective reduction in test section diameter due to deposit blockage was calculated. The preliminary experiments showed that the pressure drop increased more significantly for higher test section temperatures, and that pressure drop measurement is an effective method of monitoring and quantifying deposit buildup.
Role of Vesicle-associated Membrane Protein 2 in Glucagon-like Peptide-1 Secretion
Keywords: GLP-1
VAMP2
SNARE

Glucagon-like peptide-1 (GLP-1) is an incretin hormone produced by the enteroendocrine L-cell that potently stimulates insulin secretion. Although signaling pathways promoting GLP-1 secretion are well characterized, the mechanism by which GLP-1 containing granules fuse to the L-cell membrane remain elusive. RT-PCR and protein analysis indicate that vesicle-associated membrane protein 2 (VAMP2) is expressed and localized to secretory granules in the murine GLUTag L-cell model. VAMP2, but not VAMP1, interacted with the core SNARE complex protein, Syntaxin 1a, in GLUTag cells. Tetanus toxin (TetX) cleavage of VAMP2 in GLUTag cells prevented glucose-dependent insulinotropic peptide (GIP)- and oleic acid (OA)-stimulated GLP-1 secretion, as well as K+-stimulated exocytosis from GLUTag cells. Although components of membrane rafts were detected in GLUTag cells, their role in GLP-1 secretion remains to be determined. Together, these findings indicate an essential role for VAMP2 in GLP-1 exocytosis from the GLUTag cell.
Elucidating the Effects of Integrin-linked Kinase Modulation on Sarco/endoplasmic Reticulum Calcium ATPase Function in Human Induced Pluripotent Stem Cell-derived Cardiomyocytes
Keywords: biomedical
cardiomyocytes
integrin-linked kinase
serca2a
heart failure
dilated cardiomyopathy

Integrin-linked kinase (ILK) is an important mechanoreceptor that mediates many cellular signaling pathways. Its dysregulation causes dilated cardiomyopathy and other complications in the heart. Restoration of ILK improves cardiac function and survival, but the exact mechanism is unknown. Recent studies in our lab suggest that the cardioprotective properties of ILK may be related to its regulation of sarco/endoplasmic reticulum calcium ATPase (SERCA2a). The protein expressions of ILK and SERCA2a are positively correlated based on adenoviral transduction of ILK and siRNA targeting ILK in human induced pluripotent stem cell-derived cardiomyocytes. From analysis of their calcium transients, ILK transduction resulted in increased beat rate and faster calcium clearance while siRNA knockdown produced the opposite effect. The use of SERCA-specific inhibitor thapsigargin nullified the observed effects of ILK transduction. Based on these results, we conclude that ILK’s cardioprotective properties are partly related to improving calcium handling in cardiomyocytes through the regulation of SERCA2a.
Experimental Testing of Low Reynolds Number Airfoils for Unmanned Aerial Vehicles
Keywords: low Reynolds number airfoil
laminar separation bubble
oil film interferometry

This work is focused on the aerodynamics for a proprietary laminar flow airfoil for Unmanned Aerial Vehicle (UAV) applications. The two main focuses are (1) aerodynamic performance at Reynolds number on the order of 10,000, (2) the effect of a conventional hot-wire probe on laminar separation bubbles. For aerodynamic performance, pressure and wake velocity distributions were measured at Re = 40,000 and 60,000 for a range of angles of attack. The airfoil performed poorly for these Reynolds numbers due to laminar boundary layer separation. 2-D boundary layer trips significantly improved the lift-to-drag ratio. For probe effects, three Reynolds numbers were investigated (Re = 100,000, 150,000, and 200,000), with three angles of attack for each. Pressure and surface shear distributions were measured. Flow upstream of the probe tip was not affected. Transition was promoted downstream due to the additional disturbances in the separated shear layer.
Quenching H2O2 Residuals After UV/ H2O2 Drinking Water Treatment Using Granular Activated Carbon
Keywords: drinking water treatment
granular activated carbon
UV/H2O2
H2O2 quenching

The ability of six types of granular activated carbon (GAC) to quench H2O2 was evaluated by bench-scale H2O2 decomposition kinetics tests and pilot-scale H2O2 breakthrough tests. Bench-scale studies showed that carbon ageing significantly reduced the performance of H2O2 quenching by the GAC, but that the greatest impacts occurred within the first 25 000 bed volumes of water treated, with performance tending to stabilize afterwards. Pilot-scale studies suggested that both H2O2 exposure and exposure to natural organic matter were important factors in GAC ageing, with exposure to oxygen also suspected of being important. A continuously stirred tank reactor (CSTR)-in-series model was proposed for the prediction of H2O2 breakthrough in a GAC column.