VictorJuiz/thesis huggingface dataset:
Wavelength-modulated Intravascular Differential Photoacoustic Radar for Interference-free Detection of Vulnerable Plaques in Atherosclerosis
Keywords: Atherosclerosis
Differential imaging
Photoacoustics

As lipid (or cholesterol) composition of atherosclerotic plaques is considered to be one of the primary indicators for plaque vulnerability, a diagnostic modality that can sensitively evaluate their necrotic core is highly desirable in atherosclerosis imaging. In this regard, intravascular photoacoustic (IVPA) imaging is an emerging plaque detection technique that provides lipid-specific chemical information of diseased arterial walls. Within the near-infrared window, a 1210-nm optical source is usually chosen for IVPA applications because lipid exhibits a strong absorption peak at that wavelength. However, other arterial chromophores also show some degree of absorption near 1210 nm and generate undesirably interfering PA signals upon the same optical excitation. In this study, a novel wavelength-modulated differential photoacoustic radar (IV-DPAR) modality was introduced as an interference-free lipid detection technique for a more accurate and reliable diagnosis of plaque progression. Unlike mainstream IVPA modalities that are based on pulsed optical sources, IV-DPAR utilizes low-power intensity-modulated continuous-wave (CW) laser diodes for optical excitation. With frequency-swept optical modulation and the matched-filter pulse compression processing, IV-DPAR was demonstrated to perform spatially-resolved functional imaging on lipids with excellent signal-to-noise ratio (SNR). Signal processing algorithms were investigated to explore the novel phase-filtered amplitude (PFA) channel. By encoding the phase-derived statistical probability of the presence of lipids on the conventional amplitude channel, the PFA channel could significantly enhance various imaging parameters such as SNR and axial resolution. Most importantly, the simultaneous modulation of the two CW lasers in IV-DPAR facilitated the unique differential dual-waveform engineering technique that could efficiently suppress undesirable background absorptions and system noise to approximately zero baselines, while dramatically improving detection sensitivity and specificity toward lipids, the primary ingredient of a plaque necrotic core. When co-registered with clinically-accepted intravascular ultrasound imaging, IV-DPAR could not only locate but also quantitatively characterize the lipid contents of plaques in porcine and human atherosclerotic arteries, regardless of their size and depth.
An Investigation of the Distribution of Ozone-depleting Substances in the Upper Troposphere and Lower Stratosphere
Keywords: chlorofluorocarbons
hydrochlorofluorocarbons
stratospheric transport

Stratospheric transport in global circulation models and chemistry-climate models is an important component in simulating the recovery of the ozone layer as well as changes in the climate system. The Brewer-Dobson Circulation is not well constrained by observations and further investigation is required to resolve uncertainties related to the mechanisms driving the circulation. This work has assessed the specified dynamics mode of the Canadian Middle Atmosphere Model (CMAM30) by comparing its output to the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) profile measurements of CFC-11, CFC-12, HCFC-22, and N2O. In the CMAM30 simulation, the meteorological fields were nudged using the ERA-Interim Reanalysis and a specified tracer was employed for each halocarbon species, with hemispherically-defined surface measurements used as the boundary condition. This modified halocarbon experiment is known as CMAM30HR. A comprehensive sampling technique along the line-of-sight of the ACE-FTS measurements has been utilized to allow for direct comparisons between the simulated and measured tracer concentrations. Stratospheric transport has been investigated using CFC-11, CFC-12, and N2O. The model consistently overpredicts the concentrations of these tracers in the lower stratosphere, particularly in the Northern Hemisphere winter and spring seasons. The three mixing barriers investigated, namely the polar vortex, the extratropical tropopause, and the tropical pipe, show that there are inconsistencies between the measurements and the simulations. It was found that the simulation under- predicts mixing efficiency in the tropical lower stratosphere during the June-July-August season. The CMAM30HR simulations and the ACE-FTS measurements of HCFC-22 have also been evaluated. ACE-FTS HCFC-22 observations exhibit a small low bias compared to instruments that use a similar measurement technique. However, when compared to in situ measurements, ACE-FTS exhibits a high bias. In general, CMAM30HR exhibits a low concentration bias below approximately 70−30 hPa and a high bias above 30 hPa compared to ACE-FTS. However, the HCFC-22 comparison reveals a peak in differences between approximately 100 hPa and 50 hPa that is not consistent with the previous comparisons of halocarbon concentrations; potential explanations of the discrepancy are discussed. The most recently available ACE-FTS data are also presented and discussed.
Artificial Intelligence Planning Techniques for Emulating Agents with Application in Social Services
Keywords: behavioral psychology
bounded rationality
goal reasoning
ontology
planning
simulation

This thesis investigates the problem of emulating seemingly irrational behaviour with the use of a rational reasoner. This thesis adopts the position that human behaviour is rational but our reasoning process is bounded. To an observer with an equally rational reasoning process but different bounds, an agent's behaviour may seem irrational. The approach presented in this thesis extends a rational reasoner in classical artificial intelligence planning, STRIPS, using three theories from psychology and economics. The first theory, bounded rationality, limits an agent's reasoning ability with human-like bounds. The second theory is Maslow's hierarchy, which is used to organize and rank an agent's goals during the process of plan creation and execution. The third theory is the emotional cycle of change which is used as a nonlinear measure of expectation of success, triggering goal reranking and replanning processes during plan execution. By adopting these methods, human behaviour emulation is viewed as a classical planning problem with a non-linear evaluation function. The resulting system, Bounded Rational Agent MotivAtions framework (BRAMA), emulates trajectories of agent behaviour. The trajectories simulate agent usage patterns for various services to meet the agent's goals. The target application of BRAMA is in social services, simulating the response of homeless clients to the Housing First intervention program in Calgary, Canada. The results of the simulation can be used by policy makers to evaluate the effectiveness of alternative programs before they become policy.
Bilingualism of Korean-Canadian Children: A Multigenerational Ethnic Church In the Greater Toronto Area
Keywords: bilingualism
heritage language education
Korean-Canadian immigrants

In the midst of immigrant children’s prevalent subtractive bilingualism, this doctoral inquiry investigates multiple levels of supporting factors of Korean-Canadian children’s heritage language learning and the ways they support bilingual learning of these children, by looking at Grace Church, a multi-generational Korean ethnic church, as a case. This is an ethnographic study, which involves yearlong classroom observations and interviews with church leaders, teachers, parents, and children. Additional data sources include curriculum materials, children’s artifacts, Korean government documents and websites, as well as records of school meetings and school associations’ conferences. Employing Bourdieu’s theoretical and analytic tools, such as field, habitus, and capital (1991), this study also examines how the Korean and English languages are positioned at various levels within and beyond the church. Additionally, due to the shift made in my positionality from an observer to a participant observer, this study explores the outcomes of pedagogical changes guided by theoretical underpinnings, such as translanguaging (García, 2009), culturally relevant pedagogy (Ladson-Billings, 1994), funds of knowledge (Moll, 1992), and the third space (Gutiérrez, Baquedano-López, Tejeda, 1999). This study unveils that Grace Hangul hakgyo is a field in which the aims of the Korean government and Korean Canadian immigrants intersect vis-à-vis heritage language education. For the Korean government, it is ultimately a field for strengthening national resources and for the congregants of Grace Church, it is mainly for their heritage language and culture maintenance. In this study, the positions of Korean and English within Grace Church are revealed in the Korean and English ministries, which are closely linked to immigrant generations, and in the language use and socialization of children in the grade 3 and 4 focus class. The positions of Korean and English within Grace Church are unquestionably influenced by the status of those languages beyond the church, displaying the close relationship between language and identity at many levels of interacting fields. Finally, this study showcases how translanguaging, culturally relevant pedagogy, funds of knowledge can be utilized as a means for creating the third space in heritage language learning contexts, which is an underexamined area in the field of bilingual education.
Panitumumab Modified with Metal Chelating Polymers (MCPs) Complexing Indium‐111 and Lutetium-177 as Theranostics for Pancreatic Cancer
Keywords: 111In
177Lu
EGFR
Pancreatic cancer
Radioimmunoterapy
Theranostics

The epidermal growth factor receptor (EGFR) is overexpressed in more than 90% of pancreatic cancer (PnCa) patients. A metal-chelating polymer (MCP) with on average 13 DOTA (tetraazacyclododecane-1,4,7,10-tetraacetic acid) chelators for complexing the β-particle emitter, 177Lu and Auger electron-emitter, 111In and 10 polyethylene glycol (PEG) chains was conjugated to monoclonal antibody, panitumumab to target EGFR on PANC-1 human PnCa cells. Linking panitumumab to MCPs enabled dual labeling with 111In and 177Lu at a higher SA (55.9± 4.8 MBq/μg and 20.5± 4.2 MBq/μg) compared to panitumumab-DOTA (4.4± 0.3 MBq/μg and 2.2± 0.3 MBq/μg), with preserved EGFR binding (2.2 ± 0.6 nmol/L and 1.0 ± 0.4 nmol/L; respectively) and comparable tumour (6.9 ± 1.3% ID/g and 6.6 ± 3.3%ID/g) and normal tissue localization except for the liver uptake which was 3-fold higher for panitumumab-MCP at 72 h post injection (p.i.) in NOD/SCID mice with s.c. PANC-1 xenografts as confirmed by microSPECT/CT imaging. 177Lu-labeled radioimmunoconjugates (RICs) were more effective for killing PANC-1 cells in vitro than 111In-RICs with no significant differences between panitumumab-DOTA and panitumumab-MCP. For therapy, NOD/SCID mice or NRG mice with s.c. PANC-1 tumors were administered three amounts (10 MBq; 10 g) of panitumumab-MCP-111In or panitumumab-DOTA-111In separated by 3 weeks or a single amount (6 MBq; 10 g) of panitumumab-MCP-177Lu or panitumumab-DOTA-177Lu, respectively. Tumour growth was assessed by a tumour growth index (TGI). Panitumumab-MCP-111In or panitumumab-DOTA-111In inhibited tumour growth in NOD/SCID mice (TGI at 43 days = 3.9 ± 0.3 and 3.0 ± 0.4, respectively; P> 0.05) compared to normal saline and panitumumab treated mice (TGI = 9.8 ± 1.6, 9.9 ± 1.4, respectively; P>0.5). Similarly, panitumumab-MCP-177Lu and panitumumab-DOTA-177Lu inhibited tumour growth in NRG mice (TGI at 33 days = 2.5 ± 0.3 and 1.8± 0.3; respectively; P> 0.05) compared to normal saline and panitumumab treated mice (5.8 ± 0.9 vs. 6.1 ± 2.7, respectively; P>0.05). 177Lu-RICs deposited more absorbed doses in tumours (2-4 fold) and normal organs compared to 111In-RICs. Low absorbed doses in the normal organs for 111In allow for dose escalation. Panitumumab conjugates labeled with 177Lu or 111In are promising RIT agents for treatment of EGFR positive cancers.
Implantable Depots for Interstitial Delivery of Radiolabeled Gold Nanoparticles using a Brachytherapy Technique
Keywords: Brachytherapy
Breast cancer
Dosimetry
Gold nanoparticles
Monte Carlo simulations
Radiation nanomedicine

Radiolabeled gold nanoparticles (AuNP) are emerging as a class of therapeutics for cancer due to their unique physical and chemical properties that differentiate them from other small or bulk materials, as well as other nanoscale particles. In the ideal condition their use as a radiotherapeutic agent is facilitated by preferential extravasation from the tumour vasculature and accumulation in the interstitial space as a result of the enhanced permeability and retention (EPR) effect, following systemic delivery. This delivery scenario was anticipated to reduce the accumulation of radiolabeled AuNP in normal tissues, thereby increasing the therapeutic ratio of tumour control to normal tissue complications. However, systemic delivery of AuNP has been challenged with the inability to escape phagocytic clearance by the reticuloendothelial system (RES) coupled with suboptimal accumulation of AuNP in the tumour. Furthermore, attempts at direct intratumoural delivery of radiolabeled AuNP to circumvent RES capture and increase tumour concentrations have encountered their own limitations such as clinical feasibility and unpredictable intratumoural radioactivity and dose distribution patterns. In contrast brachytherapy, the oldest form of internal radiotherapy, has well established methods to precisely deliver radioactive material. The use of radiolabeled AuNP in brachytherapy can be mutually beneficial, offering new opportunities for brachytherapy such as use of non-photon emitting radionuclides, potential for adjuvant therapies, and dose homogenization from AuNP redistribution in the tumour interstitial space. In this thesis, a delivery system for radiolabeled AuNP is developed by designing an implantable nanoparticle depot (NPD) compatible with traditional permanent brachytherapy techniques. The design of the NPD is validated in its ability to facilitate controlled release of AuNP, resulting in predictable AuNP distributions in breast cancer xenografts in vivo. Furthermore, micro-SPECT/CT (single-photon emission computed tomography/computed tomography) image based dosimetry techniques are applied to estimate the dose distribution surrounding NPD delivery of AuNP labeled with various electron emitting radionuclides. Finally, the efficacy and toxicity of lutetium-177-AuNP NPD is evaluated in two triple negative breast cancer mouse xenograft models. In summary, this thesis outlines the design, associated dosimetry and preclinical application of radiolabeled AuNP using electron emitting radionuclides, delivered by NPD and a permanent brachytherapy technique.
A Pedagogy of Solidarity: Indigenous, Refugee Women and Women with Intellectual and Psychosocial Disabilities and Structural Violence
Keywords: feminist solidarity
Indigenous women
marginalized women
Refugee women
structural violence
Women with disabilities

Strategies to-date have been ineffective in curtailing violence against Indigenous and refugee women and women with intellectual and psychosocial disabilities in Canada. Such strategies aim to address the manifestations, rather than the foundation of the problem, namely, the relationship between capitalism, patriarchy, poverty and violence against women. Motivated by the need to address the persistent violence against these populations of women, this research offers the theoretical and practice foundations for a critical-feminist pedagogy of solidarity that would unite these groups of women to challenge structural violence. The research design employs secondary research and the primary qualitative data collection methods of focus groups and semi-structured key informant interviews. A marginalized women’s solidarity aims to refute uncritical understandings of why violence occurs, recognizing that how we understand violence informs the types of strategies we develop to address it. The findings purport that it is imperative that this feminist solidarity be exclusive to grassroots women from these specific populations, to avoid dominant ‘white’ and middle-class distractions, encouraging a narrow focus on the core structural inequities that maintain oppressive relations. The learning and critical engagement pedagogic processes aim to support women to think through the contradictions between women’s material reality and hegemonic messaging from the state. Theatre and film is highlighted as an effective tool to use in the engagement process. Solidarity learning can lead to a local to national community development strategy, led by grassroots marginalized women working on a common local need. This strategy supports local lead activities to expand nationally, resulting in a growing presence of marginalized women’s issues and dreams. The study concludes with a call for a transnational marginalized women’s solidarity that nurtures a shared understanding of structural violence against women with the aim of enacting global actions.
Defining the Relationship Between Mechanical Stress and Inadvertent Intestinal Tissue Injury In Laparoscopic Surgery
Keywords: bowel
compression
gastrointestinal injury
laparoscopic surgery
mechanical
stress

The potential to use an inappropriate amount of force when handling tissue is much higher in laparoscopic surgery than in open surgical approaches because surgeons lose the ability to directly touch and feel delicate tissue. The two most commonly injured tissues in laparoscopic surgery are the small bowel (55.8%) followed by the large bowel (38.6%) with an overall incidence of laparoscopy-induced gastrointestinal tissue injury of 0.13% but high mortality rate of 3.6%. There are currently no papers in the human literature that delineates what range of compressive stress would allow a surgeon to both operate effectively and limit the potential for tissue trauma to occur. To ameliorate this, two novel compression devices were created to produce discrete and even amounts of pressure on ex-vivo human gastrointestinal tract tissue in order to quantify the relationship between tissue stress-strain and histological measures of cellular trauma. The simple crush apparatus for tissue (SimpleCAT) consists of a weight platform and a U-shaped frame with rails. Using the SimpleCAT, significant serosal tissue deformation occurred between 350 and 450 kPa for large intestine in a pilot study of five patients. A more sophisticated compression device, the PrecisionCAT was created to investigate stress-strain and trauma in human intestinal tissue. In this study, significant tissue deformation started to occur at 300 kPa for both small and large bowel, which was also correlated to increasing pathologist trauma rating scores. Using our logistic regression analysis, the data points in the direction of establishing a maximum force threshold of 275-330 kPa on average for human intestinal tissues using a 50% threshold, however very large safety margins should be considered and used due to the high level of inter-person variation in bowel thickness and strength.
Self-efficacy and the Student Success Teacher
Keywords: Self-Efficacy
Student Success Teacher

This qualitative research study explores the self-efficacy of the Student Success teacher in the province of Ontario. The study’s participants come from four different school boards both Catholic and Public. The data was collected through face to face, and telephone interviews. The participants shared their roles and responsibilities as well as their perceived confidence in fulfilling the position of the Student Success teacher. The theoretical framework of the study is based on Albert Bandura’s Theory of Self-Efficacy. And this in turn, formed my conceptual framework which guided the questions for the study. The work and the sense of self-efficacy of the Student Success teacher were the two main areas that frame these questions. The resulting data lead to a conceptual framework with more detail. The study discovered the roles and responsibilities connected to the self-efficacy of the Student Success teacher.
The Role of T-cell Costimulation in the Pathogenesis of Kawasaki Disease
Keywords: CD40
CD40L
Kawasaki disease
Platelets

Kawasaki disease (KD) is a multisystem vasculitis that mainly targets the coronary arteries in young children. Both environmental factors along with genetic factors play a role in the susceptibility, severity and response to treatment of KD. Regardless of the initial trigger of the immune response in KD, the role of costimulatory signals remain a critical component in the survival of T-cells and the pathogenesis of the disease. Genome wide association studies have found costimulatory molecules to be associated with KD. In this work we show that, enhanced costimulation rescued superantigen-stimulated T-cells from apoptosis. CD28 mediated signaling resulted in up-regulation of the anti-apoptotic factors, Bcl-xL and cFLIP. Bcl-xL expression was dependent on costimulatory signals and decreased with administration of CTLA-4Ig. Furthermore, expression of survival molecules cFLIP, MCL1 and NAIP were significantly upregulated in patients who did not respond to IVIG treatment. Taken together, our findings point to the important role of costimulation in the immunopathology of KD. Moreover, activation of another costimulatory molecule CD40 (via CD40L) resulted in significantly elevate lymphocyte proliferation in combination with superantigen activation. However, splenocytes from CD28 knockout mice do not exhibit this elevated response and the CD28 antagonist CTLA4-Ig was able to mimic the effects seen in the splenocytes from CD28 knockout mice. This suggests that CD28 is the intermediary that mediates the proliferative effects of CD40 activation. Furthermore, the role of platelets the largest source of sCD40L was examined. Through co-culturing experiments CD40L on activated platelets was shown to promote both splenocyte proliferation and T-cell survival upon SAg stimulation. In vivo experiments using the LCWE mouse model of KD demonstrated that coronary aneurysms are reduced in the absence of CD40L. Hence, our results indicate that costimulation mediates T-cell survival in both mice and man developing KD and regulates disease severity and treatment response, pointing to a potential new target for treatment. These studies add to our understanding of the molecular mechanisms underpinning the immunopathology of KD and identify potential biomarkers of disease and novel targets for therapy.