VictorJuiz/thesis huggingface dataset:
Prevalence and Social Determinants of Overweight and Obesity in Adolescents in Saudi Arabia: A Systematic Review
Keywords: adolescent
obesity
overweight
prevalence
Saudi Arabia
social determinants

Background: The prevalence of obesity in adolescents is increasing globally at an alarming rate. Objectives: Our aim was to evaluate the prevalence of overweight and obesity (Ow/Ob) in Saudi adolescents and to construct an ecological model of social determinants of Ow/Ob and evaluate current evidence of their effect on Saudi adolescents. Methods: A systematic review of literature reported up to 31/12/2018 on Ow/Ob and factors that can influence them in Saudi adolescents was conducted. Results: Fifty-one studies with n=97,666 adolescents (56.9% males) were reviewed. The prevalence of Ow/Ob started off high and continued to increase over time. Most of the 49 reviewed social determinants reports, from 19 studies, showed positive association between social determinants and Ow/Ob in Saudi adolescents. Conclusion: Adolescents’ Ow/Ob is a major public health problem in Saudi Arabia and is growing. Social determinants play a significant role in this problem and should be considered in all strategies targeting it.
Calmodulin Disrupts Plasma Membrane Localization of Farnesylated KRAS4b by Sequestering its Lipid Moiety
Keywords: Calmodulin
Crystallography
Farnesyl
FRET
KRAS
NMR

KRAS4b is a small GTPase protein that regulates signal transduction pathways, including MAPK signaling. Recently, there has been considerable interest in the mechanisms underlying interactions between RAS and calcium signaling. KRAS4b function requires farnesylation of its C-terminus and recruitment to the plasma membrane, and some studies have suggested that Ca2+-calmodulin (CaM) modulates this localization. Here, we present a crystal structure, supported by NMR data, revealing that the Ca2+-dependent CaM-KRAS4b interaction is anchored by the sequestration of the KRAS4b farnesyl moiety in the hydrophobic pocket of the CaM C-terminal lobe. We engineered FRET-based probes (CaMeRAS) to monitor this interaction in live cells and demonstrate that, upon stimulation of Ca2+ influx by extracellular ligands, KRAS4b reversibly translocates in a Ca2+-CaM dependent manner from the plasma membrane to the cytoplasm in HeLa and HEK293 cells. These results underscore the importance of crosstalk between KRAS4b and Ca2+ signaling pathways and reveal one underlying mechanism.
Classification for Healthcare Using Linked and Unlinked Data Sources
Keywords: Healthcare
Machine Learning

Machine learning (ML) can be used to develop decision-making tools that help reduce the costs of healthcare. The data for ML tasks can be broadly categorized as linked (i.e., containing keys that uniquely identify individuals) or unlinked (i.e., lacking unique identifiers). We explore two use-cases where opportunities exist to reduce costs through ML: hospital readmission and high-resource users (HRU) of the health system. In the case of readmission classification, the relevant data is in a linked format, thereby allowing us to evaluate standard supervised learning algorithms. In contrast, the data for classification of HRUs is an unlinked format. We demonstrate that Bayesian networks are an ideal solution that allow us to integrate unlinked data from multiple sources and answer conditional queries useful for decision making. Overall, the results of this thesis allow us to expand upon the current scope of predictive models and the types of data they can leverage.
The Role of CD9 in Regulating TNF-α-Induced Expression of A Disintegrin and Metalloprotease 17 (ADAM17) in Aortic Endothelial Cells
Keywords: ADAM17
Atherosclerosis
CD9
CX3CL1
Metalloprotease
NF-κB

ADAM17 is an inducible metalloprotease that cleaves membrane-anchored proteins involved in a variety of homeostatic and pathophysiological processes. The mechanisms responsible for activation and gene expression of ADAM17 are a matter of debate, as they depend on the cellular context. Here we investigate the role of the tetraspanin, CD9, in regulating the shedding activity and gene expression of ADAM17 in human aortic endothelial cells. In contrast to what has been previously reported for other substrates of ADAM17, we found that a deficiency of CD9 did not increase ADAM17-dependent shedding of CX3CL1. Instead, knockdown of CD9 resulted in a reduction in immature and mature ADAM17 protein. This reduction was not caused by an increase in ADAM17 degradation, but rather a decrease in ADAM17 transcription. We found an associated reduction in constitutive and TNF-α-induced NF-κB activation upon knockdown of CD9, which may potentially explain the reduction in its downstream target, ADAM17.
Characterization of Pipeline Exterior and Interior Coating Material
Keywords: Accelerated tests on concrete
Concrete coating characterization
FDEM simulation
Image-based meshing
Mapping fracture network
Microscopic analysis on concrete

The characterization and performance of protective coatings for both the interior and exterior of pipelines are incorporated into this thesis. For the first part, two epoxy-based coating systems and one magnesium potassium phosphate coating system were assessed for sulfuric acid resistance under immersed pH 2.5 conditions at 38 °C for 21 days. Tests for adhesion strength, abrasion resistance as well as a microscopical assessment of the coating systems in thin sections were performed. Both epoxy-based systems performed well, but the magnesium potassium phosphate coating experienced dissolution. For the second part, protective concrete coatings applied to steel pipelines were characterized using a combined x-ray fluorescence mapping and microscopic fluorescent imaging technique. The images were used as the basis for the production of two-dimensional triangular meshes to be utilized in a finite discrete element model. These models will be used to study fracture networks developed during pipeline placement.
Wearable Hybrid Brain Computer Interface as a Pathway for Environmental Control
Keywords: Brain Computer Interfaces
EEG
EOG
Machine Learning
Riemann Geometry
Wearables

Alternative access pathways offer individuals with severe disabilities forms of environmental control through computerized commands. However, current solutions lack reliability, portability and redundancy. E-textile-based electrooculography (EOG) can offer a fast and reliable pathway but suffers from the Midas Touch Predicament (MTP). Here, we investigate the use of a hybrid brain-computer interface (BCI) to address this shortcoming. First, a subject-independent classifier is trained on two EOG systems. Then, a Riemannian framework is used to discern the “no-look” state from stimuli classes, thereby solving the MTP. Finally, the results are combined in a hybrid BCI classification scheme. The results presented show promise, with EOG classification reaching 90% accuracy between six classes and Riemann classification achieving 66% between five classes. The hybrid scheme results remain inconclusive due to data quality and null state omission from the analysis. This research project provides a basis for further investigation of hybrid systems in the development of access solutions.
U of T Works Because We Do! Neoliberalism, the Social Economy, and the University of Toronto
Keywords: Academic Capitalism
Critical University Studies
Education
Higher Education
Neoliberalism
Social Economy

The University of Toronto is one of the most important social economy organizations in Canada. However, this institution has not lived up to the potential that it has for being a powerhouse leader of the Canadian social economy. Furthermore, it's revealed that this failure is a direct result from the decisions taken by the senior administration of the University of Toronto at the expense of students, staff, faculty, and the broader Canadian public.The research presented here uses a social economy framework as an innovative lens to critically evaluate this public sector non-profit institution and is a contribution to the emerging field of inquiry called Critical University Studies. In doing so this research has been conducted by utilizing critical discourse analysis in order to examine the statements and information provided by key stakeholders existing in the academy, and specifically, those existing within the University of Toronto community.
Developing and Validating a Functional Electrical Stimulation Controller for Use with Visual Feedback Training for Standing Balance Therapy in Individuals with Incomplete Spinal Cord Injury
Keywords: Balance
Functional Electrical Stimulation
PD Control
Rehabilitation
Spinal Cord Injury
Visual Feedback Training

Incomplete spinal cord injury (iSCI) can impair standing balance, increasing fall likelihood. Visual feedback training (VFT) and functional electrical stimulation (FES) have shown promise in iSCI standing balance rehabilitation. Combining VFT and lower-limb FES was hypothesized to yield more effective standing balance therapy. This thesis developed a VFT-complementary FES system for regulating ankle muscles. In my previous work, I have developed a VFT system with another student. For my thesis project, I (1) designed an FES controller, (2) optimized the controller to mimic able-bodied ankle muscle activation data during VFT sessions, and (3) tested the resultant FES controller on able-bodied individuals as they underwent VFT to determine the effects of the FES controller on able-bodied postural control. As expected, the resultant FES-VFT system did not deteriorate able-bodied postural control. The results of this research contribute toward the development of a more effective standing balance rehabilitation system for individuals with iSCI.
Development and Application of 2D and 3D In vitro Models for Human Brain Development
Keywords: Cerebral Organoid
Organoids
Pluripotent Stem Cell
Spinal Cord Injury

For decades scientists from various disciplines have partnered to understand the most complex and fascinating organ in the human body, the brain. Despite this, the brain remains the most poorly understood area of human physiology due in large part to the lack of sample availability. Here I describe both 2D and 3D directed differentiation platforms to generate human cortical neurons and cerebral organoids, respectively from Pluripotent Stem Cells (PSCs). Cortical neurons were tested in an in vitro neurite growth assay using an inhibitory growth matrix that recapitulates the glial scar that develops following spinal cord injury. To produce cerebral organoids, I standardized production of early organoid structures and neural induction and was able to achieve reproducible production of hCOs at high efficiency (>80%). The hCOs generated using the optimized pipeline reproduce both ventricle assembly and cellular heterogeneity observed in the embryonic cortex.
In Depth Analysis of Sleep Apnea Severity
Keywords: Accelerometer
Apnea Hypopnea Index
Deep Learning
Machine Learning
Physiological Features
Portable Sleep Apnea Monitoring

Sleep apnea is a respiratory disorder affecting 10% of the adult population. The gold standard assessment of sleep apnea requires full night polysomnography in a sleep laboratory. However, polysomnography is expensive, time consuming, and inconvenient. Consequently, about 85% of adults with sleep apnea remain undiagnosed. Hence, there is a need for a convenient and robust wearable device to diagnose sleep apnea. This thesis investigates the feasibility of diagnosing sleep apnea by analyzing respiratory related movements. Polysomnography data from participants who were referred for an overnight sleep study at Toronto Rehab’s sleep laboratory was used. Simultaneously, an accelerometer attached to participants’ suprasternal notch was used to record respiratory movements. Algorithms were developed to estimate sleep apnea severity from respiratory movements. Results were compared against gold standard polysomnography. Reference intensity of respiratory event-related arousals was also calculated using clustering analysis to develop accelerometer-based arousal intensity estimation in future.
Novel Approaches to Evaluating and Characterizing Force Sensor Performance at Body-device Interfaces
Keywords: assistive devices
calibration
dynamic
interface pressure
pressure sensor
sensor evaluation

Force and pressure sensors are used to monitor fit and inform designers, researchers, and clinicians in various biomedical applications. However, sensor performance at the body-device interface is not well understood. The objective of this thesis was to develop and apply novel approaches to evaluating force sensor performance at clinically-relevant body-device interfaces. This work includes the characterization of existing transducers as well as the development of a novel sensor for assistive device applications. Clinically-relevant static and dynamic loading profiles were applied to two commercial sensors and the prototype sensor via a mechanical testing machine and an apparatus simulating the lower limb. The results of this study provide recommendations for use and summarize the effects of area of applied load, sensor configuration, tissue compliance, and calibration methods. This integration of force sensors is a vital first step towards adaptable, intelligent assistive devices that have the potential to improve fit, comfort, and performance.
Facial Emotion Recognition in Individuals with Borderline Personality Disorder and First-degree Biological Relatives
Keywords: borderline personality disorder
facial emotion recogniton
family study

Individuals with borderline personality disorder (BPD) show biases in their perceptions of facial emotional expressions. In studies that ask individuals with BPD to label or recognize emotional expressions, they frequently misattribute negative emotions to faces intended to convey no emotion and are less accurate at recognizing negatively-valenced emotional expressions. In the present study, we examined whether these emotion recognition findings are also present in individuals at familial risk for BPD. We administered a standardized measure of facial emotion recognition (FER) to 243 participants (probands, n=89; first-degree biological relatives, n=67; and controls, n=87). Our findings indicate that probands were slower and less accurate at identifying neutral faces compared to relatives and controls. Additionally, results indicated a misattribution bias wherein sad faces were mistaken as fearful more frequently in probands and relatives compared to controls. This is the first family study to investigate the extent to which the FER biases observed in individuals with BPD are familial.
Maximally Additively Reducible Subsets of the Integers
Keywords: additive number theory
combinatorics
compositions
dismal arithmetic
lunar arithmetic
sumsets

Let A, B ⊆ N be two finite sets of natural numbers. We say that B is an additive divisor for A if there exists some C ⊆ N with A = B + C. We find which subsets of {0, . . . , k} have the most divisors, and prove a correspondence between additive divisors and lunar multiplication, introduced by Appelgate, LeBrun and Sloane [1] in their study of a kind of min/max arithmetic. We use this correspondence to prove conjectures of LeBrun et al. regarding the maximal number of lunar divisors.
Effect of Vitamin C on Nitroglycerin Mediated Vasodilation in Individuals with and without the Aldehyde Dehydrogenase 2 Polymorphism
Keywords: ALDH-2
Antioxidant
Bioactivation
Hemodynamic Response
Nitroglycerin
Polymorphism

The mechanism of the bioactivation of nitroglycerin is controversial. Several enzymatic pathways have been suggested but there has been no consensus. The mitochondrial aldehyde dehydrogenase (ALDH-2) has now emerged as the primary enzyme bioactivation at therapeutically relevant concentrations. However human studies have yielded inconsistent results regarding the essential role of ALDH-2 in GTN bioactivation. We investigated the vascular response to nitroglycerin given over a wide range of concentrations in subjects with and without the ALDH-2 Glu504Lys polymorphism. We also examined the effect of supplemental Vitamin C on vascular responses to GTN in those with and without the ALDH-2 polymorphism. Forearm blood flow (FBF) responses to a brachial artery infusion of nitroglycerin were assessed using venous occlusion plethysmography. We conclude that ALDH-2 is involved in GTN bioactivation, and vitamin C co-infusion did not restore the vascular response to GTN in those that are ALDH-2 deficient.
Elucidating the Role of Histone Acetylation in Regulating Neutrophil Extracellular Trap Formation
Keywords: epigenetics
histone acetylation
histone deacetylase inhibitors
neutrophil extracellular trap formation
neutrophils
post translational modification

Neutrophils undergo a unique form of cell death to generate neutrophil extracellular traps (NETs). However, the importance of histone acetylation (e.g., acetylated histone H4, AcH4) in NET formation (NETosis) has not been established. Belinostat and panobinostat are pan histone deacetylase inhibitors (HDACis) and are widely used in clinical and laboratory applications. However, the relevance of these HDACis in altering neutrophil death is yet unknown. We considered that HDACis-induced AcH4 would dose-dependently alter neutrophil cell death between NETosis and apoptosis. The presence of HDACis (≤0.25 µM Belinostat; ≤0.04 µM panobinostat) significantly induced AcH4 and NETosis without promoting reactive oxygen species (ROS) production. Increasing concentrations of HDACis (>1 µM belinostat; >0.2 µM panobinostat) further induced H4 acetylation, NOX-derived ROS production, and significantly inhibited NETosis and induced apoptosis. However, in the presence of NETosis-inducing stimuli, higher concentrations of HDACis limited both NETosis and Apoptosis. Therefore, HDACis differentially regulate both NETosis and neutrophil apoptosis.
Investigating a Photothrombotic Pediatric Rodent Stroke Model using MRI Histology
Keywords: Animal research
Blood-brain barrier
Brain
Histological staining
Ischemic stroke
MRI

Pediatric stroke has emerged as an important cause of neurological disability in children. Animal studies of ischemic stroke show differences in lesion evolution and blood-brain barrier (BBB) permeability between adult and neonatal rodents. However, little is known about stroke evolution at the juvenile stage. Our study aimed to both qualitatively and quantitatively assess photothrombotically-induced stroke progression in juvenile rats using longitudinal MRI and histology. The assessment involved 1) characterizing the lesion and penumbra evolution; and 2) characterizing degree of BBB disruption. Our results over a 7-day period indicated lesion persistence and penumbra transformation into necrosis, as well as BBB disruption persistence. Our in-vivo and ex-vivo results provide insight into disease progression over time and could serve as a study model to test BBB stabilization agents for future clinical application in the pediatric setting.
A Comparative Study of Different Plasma Gases on Twin Wire Arc Spray Characteristics
Keywords: Coating Oxidation
Oxidation
Plasma
Plasma Forming Gas
Spray Coating
Twin Wire Arc

Oxidation during plasma spray coating is a known factor affecting coating qualities. This thesis outlines a comparative approach used to investigate how the oxygen content of plasma forming gas affects the composition of the coatings utilizing a Twin Wire Arc plasma spray torch. Firstly, this paper looks at the effects on the plasma plume and wire melting using high speed imagery. Secondly, it analyzes the oxidation of particles captured from flight. Thirdly, it investigates the oxidization of coatings sprayed at select distances from the torch by analyzing cross-sections for oxidation. Correlation of the results provides an improved understanding of the level of oxidation for composite alloy wires within the plasma spray process.
Electrophoretic Deposition of Bioactive Nanoparticles for Disinfection of Apical Root Canal Anatomy
Keywords: Dentistry
Disinfection
Electrophoresis
Endodontics
Nanoparticles
Root Canal

Objective: To utilize the principles of electrophoresis to transport and deposit cationic nanoparticles in apical root canal anatomy for enhanced antibacterial effect. Materials and Methods: The novel technological approach was assessed in two phases: i) an infected dentin block model and ii) an infected root canal model. Specimens were subjected to treatment with either: 1) electric field 2) cationic nanoparticles or 3) combined treatment. The specimens were analyzed using microbiological methods and scanning electron microscopy (SEM). Results: The results of both phases yielded a greater antibacterial effect in specimens subjected to a combined treatment with cationic nanoparticles and electric field (p
Is there Astrocyte Pathology in Posttraumatic Stress Disorder (PTSD)? Preliminary Findings of a PET Study with the Monoamine Oxidase B Radioligand [C-11]SL25.1188
Keywords: Astrocyte
MAO-B
PET
PTSD

Background: There is a lack of in vivo studies investigating astrocytes in posttraumatic stress disorder. We used positron emission tomography (PET) of the monoamine oxidase B (MAO-B) probe [C-11]SL25.1188.1188 (an index of astrocytes) to explore whether MAO-B binding is lower in PTSD and related to symptoms. Methods: [C-11]SL25.1188/PET binding was measured in 13 PTSD subjects and 17 healthy controls. Results: [C-11]SL25.1188 binding was marginally decreased in PTSD. A Group by ROI interaction suggested lower [C-11]SL25.1188 binding in ventral striatum (p =0.09) with marginal decreases in the frontal areas. [C-11]SL25.1188 binding was lower in PTSD with comorbid MDD. No relationship between [C-11]SL25.1188 and clinical features was found. Conclusion: Our preliminary findings are partly in line with preclinical literature suggesting loss of astrocytes following stress paradigms that model both PTSD and MDD. Replication of these findings in a larger cohort using stratified sampling is warranted.
Biomolecular Nanoparticle Assemblies
Keywords: DNA nanotechnology
Gold nanoparticle
Nanomedicine
Protein corona
Shapeshifing
Ultrasmall

Due to their scale, nanoparticles have great potential to treat and diagnose of diseases. Despite early promise, few nanoparticle treatments have made it past the trial phase and into the clinic. This is partially due to our lacuna of knowledge on the interactions of nanoparticles with biomolecules such as proteins and our lack of control over nanoparticle physicochemical properties following administration. This thesis attempts to address both concerns by studying nanoparticle assemblies formed with biomolecules. We begin by studying the complexes formed between sub-10 nm nanoparticles and proteins to determine which component acts as the carrier and how that affects the complexes’ biological interactions. We then apply this knowledge to design nanoparticle assemblies connected by nucleic acids that can change shape in response to biological stimuli. This research provides a foundation for new nanoparticle designs that can overcome the biological barriers that have so far frustrated the field of nanomedicine.