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Type d'Item : Item , Designing Safer, High-Performance Crosslinked Poly(ionic liquid)-Based Dielectrics(Université d'Ottawa / University of Ottawa, 2026-10-27) McKillop, Sophia; Lessard, Benoît H.Next-generation organic and flexible electronics require dielectric materials that balance high electrical performance, processability, mechanical stability, and reduced environmental risk. This thesis investigates crosslinked poly(ionic liquid) (PIL)-based dielectrics for solution-processed electronic devices. A PIL system incorporating poly(ethylene glycol) methacrylate and 2-(dimethylamino)ethyl methacrylate was synthesized and crosslinked using bis(2-bromoethyl) ether to improve compatibility with multilayer fabrication. Electrochemical impedance spectroscopy was used to evaluate how polymer composition, alkylation level, crosslinking, and counterion selection affected metal-insulator-metal capacitor performance. Optimized materials achieved high capacitance density and high electrical double-layer onset frequency, enabling integration into a proof-of-concept organic thin-film transistor. Bromide and bis(trifluoromethanesulfonyl)imide counterions were further compared through electrochemical testing and zebrafish embryo toxicity assays. By linking structure, processing, dielectric response, and toxicity, this work demonstrates that PIL properties can be systematically tuned while supporting safer polymer dielectric design for emerging electronic applications and advancing a responsible materials development framework within materials research. -- Les dispositifs électroniques organiques et flexibles de la prochaine génération nécessiteront l'usage de diélectriques qui trouvent un équilibre entre haute performance, facilité de traitement, stabilité mécanique et un faible risque environnemental. Cette thèse porte sur des diélectriques à base de polymères liquides ioniques (« poly(ionic liquid) », PIL) réticulés et traités en solution pour la fabrication de dispositifs électroniques. Un PIL intégrant du méthacrylate de polyéthylène glycol et du méthacrylate de N,N-diméthylaminoéthyle a été synthétisé et réticulé à l'aide d'éther de bis(2-bromoéthyle) afin d'adapter le système à des procédés de fabrication multicouches. La spectroscopie d'impédance électrochimique a été utilisée pour évaluer l'effet de la composition du polymère, du niveau d'alkylation, de la réticulation et du choix du contre-ion sur la performance des condensateurs métal-isolant-métal. Les polymères optimisés atteignent une densité de capacité élevée et forment une double couche électronique à une fréquence élevée. Ces propriétés ont permis d'intégrer les polymères dans la fabrication d'un transistor organique à couches minces en guise de validation de principe. Le contre-ion a ensuite été substitué par du bromure ou du bistriflimidure afin d'évaluer l'effet de celui-ci sur la performance et la toxicité des polymères à l'aide d'essais électrochimiques et d'essais toxicologiques sur des embryons de dard-perches. En établissant des liens entre la structure, le traitement, les propriétés diélectriques et la toxicité des PIL, ces travaux démontrent que leurs propriétés peuvent être ajustées systématiquement tout en favorisant une conception plus sécuritaire des diélectriques à base de polymères pour de nouvelles applications en électronique. Cela contribue à un cadre conceptuel plus écoresponsable en génie des matériaux.Type d'Item : Item , Minimum Feature Size in Proper Triangulations(Université d'Ottawa | University of Ottawa, 2026-10-27) Chouay, Youssef; Dujmović, VidaTriangulating a polygon can introduce distances between vertices and nonincident edges that are much smaller than those in the input. The minimum feature size of a crossing-free geometric graph is the smallest distance between a vertex and a nonincident edge. This measure applies to both a polygon and its triangulations, and the ratio of the input minimum feature size to that of the triangulation is the degradation. Even when Steiner vertices are allowed, some degradation remains unavoidable for proper triangulations, in which every bounded face has exactly three edges on its boundary. We prove that, for every sufficiently large N, there is an N-vertex polygon P such that every proper triangulation G of P has degradation Ω(log N). The bound holds even when any finite number of Steiner vertices may be added in the bounded face of P and on any of its edges. Together with the known O(log N) upper bound, it establishes that the worst-case optimal degradation for proper triangulations of N-vertex polygons is Θ(log N). These polygons can also be chosen so that achieving O(log N) degradation requires Ω(N) Steiner vertices. This matches the known O(N) upper bound on the number of Steiner vertices.Type d'Item : Item , A Novel Tile-Efficient AI Framework for Whole-Slide Histopathology Analysis(Université d'Ottawa | University of Ottawa, 2026-10-27) Ebrahimi, Amirhossein; Mer, Arvind SinghWhole-slide histopathology images contain rich visual information, but their gigapixel scale creates a challenging machine learning problem. Slides from a single patient can produce thousands of tiles, many of which are redundant, noisy, weakly informative, or unrelated to the target label. In weakly supervised learning, these tiles are commonly organized into large patient-level bags. This increases computational cost and can dilute the predictive signal. This work proposes a weakly supervised learning framework for efficient tile selection from whole-slide images. The framework first extracts tile embeddings using pretrained pathology foundation models, then applies dimensionality reduction, clustering, and self-supervised attention-based selection to build compact patient-level bags. These selected bags are evaluated against all-tile baselines using attention-based multiple-instance learning. Experiments are performed using whole-slide images from The Cancer Genome Atlas in a source-to-target setting. Breast cancer cases serve as the labeled source cohort, while ovarian cancer cases serve as an external target cohort. Candidate strategies are ranked using breast cancer validation AUC; the best strategy is then locked and applied to ovarian cancer. The task was to predict the mutation status of TP53. Target-cohort mutation labels are not used during training, strategy selection, checkpoint selection, or threshold selection. A domain-adversarial extension is also evaluated using unlabeled target-cohort bags to reduce domain shift. Across source-cohort candidate configurations, selected-tile bags often matched or outperformed all-tile baselines while retaining far fewer instances per patient. The validation-selected strategies also remained competitive when applied without reranking to the external cohort. These findings suggest that exhaustive tile aggregation is not always required for weakly supervised whole-slide learning. Tissue-composition analysis, stitched-slide visualization, and pseudo-expression profiles further show that selected tiles follow structured visual and image-derived molecular patterns rather than behaving like random slide regions. The approach presented in this thesis provides a framework for preserving or improving predictive performance while reducing computational cost in histopathology image analysis. By reducing the number of tiles processed during patient-level learning, the framework can lower memory demand, training time, and inference cost. With this in mind, replacing exhaustive aggregation with informed tile selection can make weakly supervised computational pathology more efficient, more inspectable, and better suited for large-scale clinical implementation.Type d'Item : Item , Trends in behaviour change techniques for implementing and de-implementing healthcare practices using audit and feedback(2026-07-28) Duncan, Hamish; Patey, Andrea M.; Crawshaw, Jacob; Presseau, Justin; Grimshaw, Jeremy M.; Ivers, Noah; Lorencatto, Fabiana; Antonopoulou, ViviAbstract Background Audit and feedback (A&F) is a widely used quality improvement strategy in which a summary of healthcare professionals’ (HCPs) practice is provided to support behaviour change. However, its application and effectiveness within randomized controlled trials (RCTs) of practice-change interventions vary considerably. Examining variation in the behaviour change techniques (BCTs) used within A&F interventions and the contexts in which they are applied may help optimise their design and delivery. Therefore, this study explored associations between the BCTs used in A&F interventions, the direction of behaviour change (implementation versus de-implementation), and target behaviour type. Methods An exploratory secondary analysis was conducted using data from 261 RCTs of A&F interventions, originally extracted as part of a Cochrane systematic review. Binary logistic regression models investigated whether different BCTs were more frequent in interventions for the implementation versus de-implementation of HCP practice. These analyses were repeated in subgroups of different behaviour types (e.g. prescribing, testing/examinations). Results Descriptive analyses of 261 RCTs (942 target behaviours) indicated that BCTs were used with broadly similar frequency for implementation (n = 732 behaviours) and de-implementation (n = 179 behaviours). Due to substantial clustering within studies, regression model estimates were unstable and not interpreted inferentially. Across the full sample, most BCTs showed minimal differences in use between implementation and de-implementation. Subgroup analyses by behaviour type suggested some variation, with certain BCTs (e.g. feedback on outcomes of behaviour) appearing to be used differentially depending on the type of practice being modified. However, overall patterns were largely consistent across behaviour categories. Conclusions These findings suggest that A&F interventions typically use similar BCTs regardless of whether they aim to increase or decrease HCP behaviours, and largely irrespective of behaviour type. This may indicate that current A&F intervention design does not systematically account for the direction or nature of behaviour change. While some variation was observed by behaviour type, the absence of clear differentiation highlights a potential mismatch between theoretical expectations and practice. Future research should use theory-informed designs to determine whether tailoring BCTs to behaviour change direction or type improves A&F intervention effectiveness.Type d'Item : Item , Real-World Effectiveness of Mavacamten in Canada: Insights from the MAVEN Study(2026-10-22) Ward, Michael R.; Crean, Andrew M.; Desplantie, Olivier; Tyrrell, Benjamin D.; Corriveau, Stéphanie; Brellier, Florence; Ong, Kevin C.Abstract Introduction Previous studies have demonstrated the efficacy and safety of mavacamten in patients with symptomatic obstructive hypertrophic cardiomyopathy (oHCM), primarily outside of Canada, with limited Canadian real-world data evidence. The MAVEN study aimed to describe the real-world effectiveness of mavacamten in Canadian patients with oHCM. Methods This multi-center, retrospective physician survey of patient charts included 115 patients with oHCM who initiated mavacamten between January 2023 and November 2024 across five Canadian sites. Effectiveness was assessed by changes in clinical characteristics and outcomes, including New York Heart Association (NYHA) functional class, resting and Valsalva left ventricular outflow tract (rLVOT and vLVOT, respectively) gradients, and left ventricular ejection fraction (LVEF), from treatment initiation to the most recent available assessment. Results Baseline demographic and clinical characteristics were consistent with previously published data (median age 63.0 years; 66.1% aged ≥ 60 years; 51.3% male, 48.7% female patients; 57.4% NYHA class II, 42.6% NYHA class III). Median baseline rLVOT and vLVOT gradients were 44.0 and 78.0 mmHg, respectively, and median LVEF was 65.0%. Overall, 72.7% of patients improved by ≥ 1 NYHA functional class. Median reductions in rLVOT and vLVOT gradients were − 25.5 (interquartile range [IQR]: − 61, − 8) mmHg and − 51.0 (IQR: − 83, − 24) mmHg, respectively, while median LVEF changed by − 3.0% (IQR: − 8, 0). Mavacamten was discontinued in 8.7% of patients, including 2.6% due to treatment-emergent adverse events. Reductions in LVEF < 50% were observed in 6.1% of patients, and no patient experienced an LVEF < 30%. Conclusions In this first Canadian real-world study of mavacamten effectiveness, treatment was associated with improvements in symptoms and LVOT obstruction. Reductions in LVEF < 50% were observed in a minority of patients, with no cases of LVEF < 30%. Given the retrospective design and heterogeneous follow-up of this study, these findings should be interpreted cautiously. Graphical abstract available for this article. Graphical Abstract