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Investigating Systems Thinking in Chemistry Education: Students’ and Educators’ Experiences and Perspectives
No full textChemistry knowledge is essential in addressing solutions to complex global challenges such as achieving the United Nations’ Sustainable Development Goals (SGDs), which include climate action, good health and well-being, and quality education. However, chemistry knowledge is often taught in silos of individual topics to achieve a depth of understanding, placing less emphasis on making connections to other disciplines or global issues. Calls have been made to reimagine how chemistry is taught so that citizens and chemists can contribute to solutions to these complex global challenges. Researchers and educators have been exploring systems thinking (ST), which has been proposed as part of an approach to chemistry education. ST aims to understand and interpret complex problems from a holistic perspective. ST has a goal to better equip citizens and future scientists for the interdisciplinary work needed to address these emerging global issues. However, there has been limited evidence-based research on what ST looks like or its impact on chemistry education. Without evidence, uncertainty will persist on how to effectively implement ST in chemistry education and wide-spread implementation will remain a challenge, limiting the ability to equip people with the knowledge and skills to understand and solve these global challenges. My doctoral thesis has contributed to this area of need by investigating students’ and educators’ perspectives and experiences of ST approaches in chemistry education. We found 56 chemistry educators’ willingness and ability to implement ST in chemistry education is influenced by their knowledge, beliefs, experiences, contextual and personal factors (Chapter 2). Additionally, barriers related to educators’ knowledge on ST and contextual factors (e.g., limited time to learn and teach ST, limited teaching resources and assessments) were rated the highest among educators. This work can guide priorities for educational change efforts to reduce barriers for implementing ST in chemistry education. In addition to learning about educators’ perspectives and experiences with ST in chemistry education, we investigated students’ perspectives and experiences when engaging in ST tasks, as they are also key stakeholders who must be considered when implementing ST. We created a ST intervention in which 26 undergraduate and graduate students, taking chemistry courses, engaged in three ST tasks and interviews. We identified ST skills that these students do and do not demonstrate readily, to understand which skills need to be explicitly scaffolded in their instruction (Chapter 3). While most students demonstrated most of the 11 ST skills assessed, some aspects of the skills were demonstrated less frequently, drawing attention to areas that need to be explicitly taught and scaffolded. The aspects demonstrated less frequently in students’ systems maps include: (1) fewer concepts and connections at submicroscopic levels of granularity (e.g., molecular, atomic, subatomic), (2) limited circular loops and causal connections, and (3) no connections that considered human impact on chemistry. This work was one of the first that provided some understanding of how to assess ST skills in chemistry education. The research in Chapter 4 explored students’ experiences more broadly by looking at their engagement with individual and collaborative ST tasks during the intervention and identifying aspects of ST that may be beneficial and challenging for students. Students shared more positive than negative experiences with the ST tasks. One beneficial experience was recognizing and appreciating different perspectives and ideas from their group members, bringing attention to important implications related to equity, diversity, and inclusion in chemistry education. We also found that students had varying positive perspectives based on their engagement with the ST tasks and their perspectives of other students engaging with ST in a chemistry course. Implications of this work include specific recommendations on how to approach ST instruction for chemistry teaching and learning. These recommendations were considered in the design of a new ST study to investigate the impact of using a ST approach to support the evaluation of scientific misinformation (Chapter 5). In addition to the chemistry education research in Chapters 2 to 4, my doctoral degree focused on curriculum development by using some of these research findings to inform the development of a ST framework, helping educators to plan, implement, and assess ST in chemistry education (Chapter 6). We have made significant contributions to areas of ST that had not been previously explored, creating momentum for future research on ST in chemistry education. There are still many research opportunities on ST needed to explore cognitive and affective outcomes as well as EDI and long-term transfer of knowledge and skills in chemistry. Our research has helped identified what ST looks like in chemistry education, now educators and researchers can use this knowledge to investigate how ST approaches impact the field
Criteria used to define appropriate red blood cell transfusion in the perioperative setting: a scoping review
No full textAbstract Introduction Intraoperative red blood cell (RBC) transfusion strategies vary depending on multiple factors. Several studies have documented significant variability in RBC transfusion practices during surgery. This scoping review aimed to identify and describe existing criteria or clinical decision-making tools used to evaluate intraoperative and immediate post-operative RBC transfusion appropriateness. Methods A scoping review was conducted and reported according to Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines with extension for scoping reviews. A systematic search of MEDLINE and EMBASE was conducted. Relevant references were also explored. Studies reporting on the development, use, or validation of a clinical tool or set of criteria to adjudicate the appropriateness of intra- or post-operative RBC transfusions were eligible for inclusion. Results A total of 3,342 de-duplicated articles were identified. 135 underwent full text review, and 28 were included in the analysis. One tool was designed specifically for use during surgery. Adjudication of perioperative RBC transfusion appropriateness was determined using pre-existing published society guidelines in 61% of studies. 29% used a pre-defined set of criteria selected by the study team, and one study used RAND-UCLA to achieve consensus on appropriate transfusion criteria. Conclusion This review identified several tools that were used to adjudicate the appropriateness of intraoperative and immediate postoperative RBC transfusions. Almost all studies adjudicated transfusion appropriateness based on guidelines intended for use outside of perioperative settings. Further research is required to develop RBC transfusion adjudication criteria that specifically integrate the unique factors that influence transfusion in the perioperative setting
Mitochondrial ATP-Dependent K⁺ Channels Downregulate Ionotropic Glutamate Receptors During Hypoxia in Retinal Horizontal Cells of Goldfish
No full textRetinal neurons rely on a continuous supply of oxygen to maintain function, yet some species like goldfish can withstand prolonged hypoxic periods due to adaptations that remain unclear. Horizontal cells (HCs) are interneurons in the retina that shape visual signalling by feeding back to photoreceptors. In the present study, we investigated whether ionotropic glutamate receptors (iGluRs) in goldfish HCs are suppressed during hypoxia and whether this process is mediated by mitochondrial ATP-sensitive K⁺ (mK_ATP) channel activation. Through perforated patch-clamp electrophysiology, we determined that glutamate application under hypoxia reduced median peak current density by ~10.5% (P = 0.0059), whereas control recordings in normoxia showed stable responses. When mK_ATP channels were blocked with 100 μM glibenclamide during hypoxia, the suppressed response was abolished. Inhibiting mitochondrial calcium (Ca²⁺) uptake via the mitochondrial Ca²⁺ uniporter (MCU) with ruthenium red and blocking Ca²⁺ release through ryanodine receptors in the endoplasmic reticulum also abolished the hypoxia-induced suppression. Taken together, these results indicate that mK_ATP activation triggers a controlled Ca²⁺ signal that downregulates iGluR activity in the membrane. Through the reduction of receptor activity, HCs may lower their metabolic demand, allowing them to maintain cell function during hypoxia. The proposed mechanism can ultimately provide insight into treating retinal conditions associated with hypoxia such as retinal ischemia and stroke
Controlling Thermal Emission and Light Matter Interaction using Phonon-Induced Epsilon-Near-Zero Materials in the Mid-Infrared Region
No full textThis thesis explores phonon-induced epsilon-near-zero (ENZ) materials as a platform for tailoring light-matter interactions in the mid-infrared (mid-IR) spectral regime. After introducing the fundamental concepts of thermal emission, light-matter interaction in subwavelength structures, and the unique electromagnetic properties of polar dielectrics near their optical phonon resonances, we show how ENZ conditions can (i) enable spectrally selective, temporally improved thermal emission and (ii) support strong coupling between gap-plasmon resonances and ENZ phonon-polaritons.
The first research project of my thesis investigates ultra-thin silicon dioxide (SiO₂) films, which support phonon-polariton resonances near their longitudinal optical (LO) phonon frequency. By leveraging the dispersive behavior of SiO₂ in the ENZ regime, we demonstrate spectrally selective and temporally coherent thermal emission from structures with thicknesses much smaller than the emission wavelength. Full-wave electromagnetic simulations, supported by angle- and polarization-resolved emissivity measurements, confirm the emergence of partially coherent thermal radiation, offering a platform for narrowband mid-IR thermal sources.
In the second part of the thesis, we study the strong coupling between gap-plasmon resonances - supported by a metallic-dielectric-metal antenna array - and the ENZ phonon-polariton mode of an ultra-thin aluminum oxide (Al₂O₃) film. This interaction gives rise to hybrid polaritonic states characterized by modified dispersion and strong field confinement. Numerical and experimental investigations confirm that the system operates in the strong coupling regime, with tunable mode positions achieved by varying structural parameters such as antenna dimensions and ENZ film thickness.
Finally, we present a numerical study of field enhancement in the coupled gap-plasmon-ENZ system. Simulations reveal that decreasing the ENZ film thickness leads to significant field concentration within the structure, with electric field magnitudes approaching two orders of magnitude above the incident field. These findings underscore the potential of ENZ-coupled plasmonic systems for enhancing nonlinear optical effects and advancing mid-IR photonic applications
Adaptive Translational Regulation in Response to Low-Dose Gamma Irradiation in HFL1 Lung Fibroblasts
No full textUnderstanding the cellular responses to low-dose ionizing radiation (IR; ≤ 0.1 Gy) is essential for developing evidence-based radiation protection policies. While the effects of high-dose IR on gene expression and protein synthesis are well documented, how cells selectively remodel their gene expression under low-dose IR stress remains poorly understood. To address this gap, I performed ribosome profiling on normal human lung fibroblast cells exposed to low (0.1 Gy) and high (1 Gy) doses of ⁶⁰Cobalt gamma (γ) rays. At 1 and 6 hours post-irradiation, the results demonstrate that while low-dose IR does not significantly change global protein synthesis, subsets of mRNAs show distinct increases or decreases in translation efficiency. These translational changes contrast with minimal alterations observed at the transcriptional level following low-dose exposure. The data suggest that specific biological processes are modulated upon low-dose γ-radiation. The small GTP-binding protein RAB33B was identified as a translationally upregulated target in response to IR. This study emphasizes that conventional transcriptome analyses do not fully capture gene expression dynamics in response to low-dose IR exposure. Moreover, I identify dose-rate as a confounding factor, highlighting the importance of considering both dose-rate and cumulative dose in experimental design. Understanding the features that govern preferential mRNAs translation or repression in response to γ irradiation may offer deeper insights into the subtle adaptive responses to common low-dose radiation exposures from the environment, medical devices, or occupational activities
The Role of Relational Healing in Psychedelics: A Comparative Study
No full textPsychedelics, acting primarily through 5-HT2A receptor binding and modulation of networks such as the default mode network (DMN), can induce shifts in self-perception, cognition, and emotion by promoting neuroplasticity and altering entrenched thought patterns. The biomedical model, emphasizing measurable neurochemical processes, often attempts to extract these neuroplastic benefits while downplaying subjective experiences. This approach may neglect essential elements of mental health, as psychological well-being is tied closely to meaning, context, relational dynamics, spiritual well-being, and community support. Medical anthropology and social constructionist theories demonstrate that focusing solely on a pharmacological viewpoint reduces psychedelic therapy to a biochemical intervention, ignoring cultural, communal, and existential dimensions of healing. As well, standard methods fail to address how risk, suffering, and spiritual experiences factor into transformative therapeutic processes. A holistic approach that acknowledges both neurobiological mechanisms and lived realities is thus critical.
"Set and Setting" underscore the significance of mindset and environment in shaping outcomes, revealing that therapeutic benefits cannot be attributed solely to neurochemistry. This recognition challenges reductionist models and encourages an integrative understanding of healing, centered on subjective experience and relational factors. "Psychedelic Sociality" emphasizes the importance of non-pharmacological variables such as community support, cultural context, and shared meaning-making, in influencing therapeutic results. Because psychedelics operate within a biopsychosocial framework, it is vital to consider co-evolutionary processes, ritual elements, and synergistic "entourages". While Indigenous traditions often view psychedelics as sacred, relational agents within community and ecology, Western approaches generally administer them strictly as pharmacological tools, overlooking broader relational, cultural, and spiritual dimensions
Short-Term Efficacy of Lebrikizumab Versus Dupilumab in Combination with Topical Corticosteroids in Adults with Moderate-to-Severe Atopic Dermatitis: Matching-Adjusted Indirect Comparison
No full textAbstract Introduction A matching-adjusted indirect comparison evaluated the short-term efficacy of lebrikizumab plus topical corticosteroids (TCS) versus dupilumab plus TCS in adults with moderate-to-severe atopic dermatitis (AD). Methods Individual patient data from the ADhere trial (lebrikizumab 250 mg every 2 weeks [Q2W] plus TCS) and aggregate data from the CHRONOS trial (dupilumab 300 mg Q2W plus TCS) were matched using the method of moments approach to adjust baseline differences. Matching was done at the study level (primary analysis) and at the study arm level (sensitivity analysis). Efficacy endpoints up to week 16 included the proportion of patients achieving an Investigator’s Global Assessment of 0 or 1 (IGA 0/1); a ≥ 50%, ≥ 75%, and ≥ 90% improvement from baseline in the Eczema Area and Severity Index (EASI 50/75/90); a ≥ 4-point improvement from baseline in the Pruritus Numerical Rating Scale score (PNRS ≥ 4); and a ≥ 4-point improvement from baseline in the Dermatology Life Quality Index score (DLQI ≥ 4). Placebo-adjusted efficacy outcomes were compared using odds ratios (ORs), risk ratios (RRs), and risk differences (RDs) with 95% confidence intervals (CIs). Results At week 16, lebrikizumab plus TCS had comparable odds to dupilumab plus TCS of achieving EASI 75 (OR 1.14, 95% CI 0.42–3.09), IGA 0/1 (OR 1.39, 95% CI 0.42–4.59), PNRS ≥ 4 (OR 0.48, 95% CI 0.17–1.37), and DLQI ≥ 4 (OR 0.89, 95% CI 0.29–2.69). At earlier timepoints, lebrikizumab plus TCS had comparable odds to dupilumab plus TCS of achieving PNRS ≥ 4 at week 2 (OR 2.04, 95% CI 0.24–17.05) and week 4 (OR 3.59, 95% CI 0.90–14.36). RR and RD estimates were consistent with OR estimates of efficacy. Sensitivity analyses confirmed the findings of the primary analysis. Conclusion Lebrikizumab plus TCS was comparable to dupilumab plus TCS across all efficacy endpoints at week 16
Concerning the Ottawa River
No full textThis thesis explores relations with the Ottawa River - both historically and in the contemporary - in the context of settler colonialism. Through a combination of archival research and ethnographic fieldwork, I trace how the Ottawa River has been taken up as a concern in settler discourse, emphasizing how these concerns shift and drift across time and landscape. My thesis argues that settlers' relations with the Ottawa River shape conceptualizations of control and governance through resource extraction, nation-building, and securing ecological futures. My research traces historical processes that have shaped the riverine environment and which resonate in the contemporary. I show how concerns about settlement, aesthetics, and the future are linked.
Settlement is a main theme in river relations in Ottawa's early colonial period as a lumber town. As Ottawa became a centre of vice-regal elites, chosen as the nation's capital, tension emerged between use of the river for resource-extraction and aesthetic concerns, which are related to ecological concerns around pollution and good citizenship. These latter concerns link with, while not entirely aligning with, the aim of Ottawa Riverkeeper - a grassroots environmental NGO which is the main site of my fieldwork - to help sustain a healthy Ottawa River Watershed now and in the future. --
Cette thèse explore les relations - à la fois historiques et contemporaines - avec la rivière des Outaouais dans un contexte de colonialisme de peuplement. En combinant un travail d'archives avec celui du terrain ethnographique, j'entreprends de tracer comment la rivière des Outaouais a été saisie en tant qu'enjeu au sein du discours colonial, en mettant l'emphase sur la manière dont les problématiques qui lui sont liées glissent et dérivent à travers le temps et le paysage. J'y propose que les relations des colons avec la rivière des Outaouais informent certaines conceptualisations du contrôle et de la gouvernance par l'extraction de ressources, la construction nationale et la sécurisation de futurs écologiques. Ma recherche trace les processus et les structures historiques qui ont informé l'environnement riverain et résonnent au contemporain. Je démontre que la manière dont des préoccupations pour le peuplement, l'esthétique et le futur y sont liées.
Le peuplement par les colons constitue l'un des thèmes principaux des relations fluviales pendant la période coloniale précoce d'Ottawa en tant que ville d'exploitation forestière. À mesure que la ville devient un centre pour les élites liées au consort vice-royal puis la capitale nationale, une tension émerge entre l'utilisation de la rivière pour l'extraction de ressources et certains enjeux esthétiques, qui rejoignent des préoccupations écologiques quant à la pollution et à la bonne citoyenneté. Ces dernières sont liées, sans toutefois pleinement s'aligner, aux objectifs du Garde-rivière des Outaouais - une ONG environnementale communautaire qui constitue le site principal de mon terrain - pour le maintien de la bonne santé du bassin versant de la rivière des Outaouais, aujourd'hui et à l'avenir
Competitive Authoritarianism in the Era of Cohabitation: Neopatrimonialism and Transhumance in the Democratic Republic of the Congo
No full textAlthough there is abundant literature on cohabitation and the peaceful exit of autocrats from power, rarely have scholars studied the two events occurring simultaneously in a singular state. My goal was to fill this knowledge gap and to provoke new thoughts around cohabitation as an emerging practice of authoritarian resilience. Scholars have extensively theorized that authoritarian rulers are mainly driven by the desire to preserve power (Bueno de Mesquita et al., 2003), prompting academics to explore the different strategies autocrats use to sustain their survival (Levitsky and Way, 2010). While some scholars have projected the political “death” of autocrats after losing power, others have focused on studying what happens to the regime when the autocrat begins to age (Tanaka, 2018). Thus, this study aimed to build on the literatures that emphasize the political ‘death’ of autocrats after ceding power by investigating the political “afterlife” of an autocrat in his post-tenure period. In the last two decades, there has been a growing scholarly interest in studying how autocrats prepare to exit from power and how their post-tenure exit strategies influence whether they will leave office peacefully or face a severe ending.
Building on Englebert’s (2019) study, I investigate how a former autocrat, despite not having an official position, ensured that the opposition remained loyal to the deal it made – a “devil’s bargain,” where the new president would ascend to power while the former ruler controlled the legislative majority (Englebert, 2020). My second aim was to examine how the new ruler, who rose to power without the legislative majority, managed to gradually dismantle his predecessor’s control over the state’s institutions and shift the balance of power to his favor during the cohabitation period. As a qualitative research design based on an interpretative case study, the key objective of my dissertation was to trace the residual shadow of the former ruler, Joseph Kabila, and Felix Tshisekedi’s trajectory of power consolidation
Engineering Dynamic Extracellular Microenvironments: Temperature-Casted Collagen-Fibronectin Scaffolds with Controlled Structure, Mechanics, and Cell-Driven Re-Organisation
No full textUnderstanding how to engineer biomimetic scaffolds is critical for advancing tissue engineering, regenerative medicine, and disease modelling. This thesis investigates the design, fabrication, and characterization of three-dimensional (3D) extracellular matrix (ECM) scaffolds, focusing on collagen - fibronectin (ColFn) hydrogels that closely replicate native ECM environments.
The introductory chapters establish the fundamental principles of tissue engineering, emphasizing the role of collagen and fibronectin in ECM mechanics, cellular interactions, and mechanotransduction. Building upon this framework, the thesis integrates advanced confocal microscopy and oscillatory rheology to enable high-resolution, real-time imaging and precise mechanical analysis of ECM scaffolds.
A temperature-controlled fabrication technique was developed to modulate scaffold architecture and mechanical properties. Incorporating fibronectin significantly enhanced scaffold stability, fibre organization, and cellular engagement, supporting dynamic reorganization processes essential for tissue regeneration. The experimental work highlights how fibronectin modulates collagen fibre formation kinetics, increases ECM stiffness, and promotes cell adhesion and migration.
Live imaging and rheological analyses revealed that fibroblasts dynamically remodel their microenvironment, forming pericellular collagen - fibronectin micro-islands and aligning fibres along force axes. Importantly, a critical cell concentration was identified, beyond which collective cell generated forces induced a phase transition in the ECM. At low cell densities, cells contributed to local stiffening and retained more space to spread and interact with their surroundings. However, as cell density increased, mechanical stress and crowding altered ECM behaviour, transforming the structure from a continuous fibrous network into distinct, clustered islands of collagen and fibronectin. This structural shift was accompanied by a substantial increase in ECM stiffness, reflecting how cell density and mechanical feedback collectively govern matrix architecture and mechanical properties. While these observations parallel aspects of natural tissue remodelling, they are unique insights into the phase transition behaviour of engineered ECM under cellular stress.
Overall, this thesis provides a comprehensive framework for understanding scaffold design, ECM reorganization, and cellular interactions under physiologically relevant conditions. By integrating scaffold fabrication methods with mechanobiological insights, the findings contribute to the development of next-generation, bioactive materials for regenerative medicine and tissue engineering applications