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Toward the Sustainable Production of Feedstock Chemicals via Olefin Metathesis
No full textThe transition to sustainable chemical production requires a shift from petroleum-based feedstocks to renewable resources: terrestrial and aquatic biomass, and waste materials. Efficient catalytic systems are essential to achieving this goal. Olefin metathesis is a key methodology in this context, offering atom-efficient methods for the transformation of renewable chemicals into specialty and value-added products. Despite this transformative potential, large-scale adoption of olefin metathesis is constrained by challenges in catalyst stability and productivity. This thesis explores barriers to the implementation of olefin metathesis for sustainable chemical production and presents strategies to address these challenges.
The first focus of this thesis was improving the synthesis of highly productive catalysts that bear cyclic (alkyl)(amino) carbene (CAAC) ligands. Ru-CAAC catalysts are desirable for their breakthrough productivities in olefin metathesis, but the routes by which they are synthesized are plagued by low yields, particularly in the carbene installation step. By isolating problems in carbene generation from potential inefficiencies in carbene complexation to Ru, this work uncovered a previously unrecognized side-reaction in which free CAACs are consumed by a lithium tetrafluoroborate coproduct. Subsequent studies focused on clarifying which of several postulated side-reactions do indeed occur during carbene generation. The primary problem was traced to dimerization via nucleophilic attack of the free CAACs on their iminium salt precursors. These studies revealed the unexpected stability of CAAC carbenes in solution and led to the isolation of the first free CAACs sufficiently small to confer high activity in olefin metathesis. By mapping out the major factors that limit carbene and catalyst yields, this work offers a guide to improved synthetic protocols.
Also examined were factors that contribute to catalyst decomposition during metathesis. Catalyst decomposition caused by oxygen, a ubiquitous contaminant, is a challenge for metathesis catalysts based on virtually all transition metals. Ruthenium catalysts constitute an exception: as a class, they have proved oxygen-tolerant to an impressive degree. The present work reveals that this robustness is not invariable. A subset of ruthenium-thiocatecholate catalysts that is employed for stereocontrolled metathesis is shown to undergo very rapid oxidation, leading to loss of the alkylidene ligand as the aldehyde. Decomposition pathways intrinsic to the dominant class of phosphine-free ruthenium catalysts were also re-analyzed. These culminate in nanoparticles as the ultimate decomposition products of the important N-heterocyclic carbene (NHC) catalysts. The NHC-nanoparticles were shown to be highly active in olefin isomerization, the major selectivity-limiting side-reaction in olefin metathesis. In comparison, CAAC catalysts form fewer nanoparticles, and are isomerization-inactive. Nevertheless, they are likewise highly susceptible to bimolecular decomposition. The classical solution to this problem, site-isolation via catalyst immobilization, severely restricts catalyst activity. In a novel approach aimed at preventing bimolecular decomposition while retaining molecular catalysts, the widely-used NHC ligands were redesigned. Functionalizing the carbene ligands with bulky trityl groups at the 'wingtip' positions indeed inhibited degradation and enhanced productivity.
The final work in this thesis showcases two advances aimed at renewable applications. The first exploits the trityl catalysts, with their resistance to bimolecular coupling, for the efficient transformation of phenolic stilbenes - a recalcitrant class of compounds found in plant extractives and lignin waste - into high-value products. The second outlines key principles for fluorophore-tagged CAAC catalysts designed for an ambitious goal: transforming unsaturated fatty acids within living extremophilic algae to produce olefin building blocks as sustainable alternatives to petroleum products. A fluorophore with enhanced photostability and improved selectivity for staining algal lipids was identified and integrated into the catalyst structure. While tuning lipophilicity versus water-solubility is required to enable catalyst uptake within living algae, the fluorophore alone suffers no such constraints, and indeed represents a new tool for algal biology.
These findings provide insights into front-line challenges in catalyst synthesis, stability, and design for demanding applications, ultimately expanding the scope of olefin metathesis. By identifying side-reactions that limit synthetic yields of CAAC catalysts and elucidating overlooked decomposition pathways and products, these studies pave the way toward application-guided catalyst design. The successful application of robust CAAC and NHC catalysts in renewable applications highlights the potential for sustainable chemical transformations. Collectively, these findings further advance our understanding of catalyst behavior in olefin metathesis, and help lay the groundwork for future innovations to bridge the gap between bench-scale and industrial processes
La IA en las urnas: Cuatro medidas para salvaguardar la integridad electoral y defender la democracia
No full textEjemplos recientes de Brasil, Rumanía, Gabón, Estados Unidos y otros países muestran cómo el uso de la IA por parte de actores políticos puede afectar negativamente la integridad electoral y la democracia.
Las naciones no suelen estar preparadas para los retos relacionados con la IA: muchas carecen de normas que regulen el uso de la IA en las elecciones, los partidos políticos no se han puesto de acuerdo sobre prácticas electorales justas en la era de la IA y la mayoría de las jurisdicciones no pueden contrarrestar eficazmente los ataques realizados con IA en contra de sus instituciones democráticas.
Recomendamos cuatro acciones: los Estados deberían actualizar las normas electorales (por ejemplo, para prohibir los contenidos engañosos generados con IA); los partidos políticos deberían adoptar un código de conducta con directrices claras sobre el uso responsable de la IA en actividades políticas; las autoridades electorales deberían establecer equipos independientes para prevenir y responder a las perturbaciones provocadas con IA; y, a nivel internacional, los gobiernos deberían establecer Guardianes Electorales Internacionales de IA y protocolos para abordar las interferencias transfronterizas.Este proyecto se ha llevado a cabo gracias a la contribución del Fonds de recherche du Québec, del CEIMIA, de la Chaire Canada-CIFAR en IA et droits de la personne del Mila, y de la Chaire de recherche de l’Université d’Ottawa en technologie et société, y con la ayuda de la Délégation du Québec à Rome y la SIOI para la organización del retiro
Crowding Out of Private Contributions by Government Funding: The Importance of Charitable Activities and Population Served
No full textExisting literature on crowding out typically focuses on donations to any charity or to those providing services in specific areas, like arts or social services. We depart from this literature by focusing on all charities that serve a specific geographic/cultural population, namely Indigenous peoples. This specific population is of interest for several reasons. Firstly, charities that serve Indigenous people are much more likely to receive government funding relative to all other charities: 57% versus 35%. We wonder if government funding helps explain the large difference in average donations to Indigenous-serving as compared to non-Indigenous serving charities. Secondly, we know very little about the role of the charitable sector in serving the Indigenous population even though it is amongst the most vulnerable in Canada. We uncover several useful findings: government funding always crowds out Indigenous-serving charities; the crowding-out of Indigenous-serving charities is usually larger but never smaller than that of non-Indigenous serving ones; and the crowding-out of Indigenous-serving charities is invariant to whether the charity is located on or off reserve
Using a Knowledge Translation-Integrated Approach Aimed at Helping Blended Families Flourish
No full textThere are significant gaps in programming for blended families to reduce their higher risk of marital dissolution and to promote resilience. A Knowledge-Translation Integrated approach (KTI) was carried out to compare three different psychoeducational workshops developed in collaboration with and for blended families (i.e., stakeholders), adapted from family therapy models (Satir, Emotionally Focused Family Therapy, and Rational Emotive Attachment Logotherapy—now called Meaning Mindset Therapy). The KTI methodology included a qualitative needs assessment and the development of psychoeducational workshops based upon the needs assessment and these three therapy approaches. Five specific needs for blended families were derived from the literature review in addition to the needs assessment and were evaluated by the blended family stakeholders. These specific needs foundational to the development of the workshops included: maintaining a solid couple bond and parent coalition; dealing with losses, loyalties and change; managing dividing parenting/stepparenting tasks; building a new family culture and addressing stigma; and acknowledging other parents and relatives as still part of the family. Five exercises were derived from these five specific needs to develop a brief psychoeducational workshop program with each of the three proposed family therapy approaches adapted for blended families. This pilot program evaluation was conducted through three two-part workshops with nine blended families (three families per workshop type) to meet the five specific, evaluated needs from the needs assessment. The psychoeducational workshops were conducted to determine if the three approaches warranted further study or development. The pilot program also measured if meaning, well-being, attachment, and resilience improved after the workshops. Since alliance appeared to be related with meaning, well-being, attachment, and resilience, this pilot-study also accounted for alliance as a possible explanatory factor, as previous research noted that it can be a key predictor of treatment outcome. With the needs assessment, the stakeholders recommended going ahead with the implementation of the workshops evaluated. They also identified areas of targeted needs beyond the five specific needs from the literature, such as mental health support, family bonding, meaning-making and spirituality, and communication skills. After implementation of the three blended family workshops, meaning and psychological well-being improved from pre-test to post-test in both qualitative and quantitative findings for all three workshops, although alliance may have been a contributor. The qualitative findings suggested that participants wanted longer-lasting support than the conducted two-part workshop. Since all three workshops were associated with promising outcomes, a REALSELF Integrated Treatment Protocol incorporating all five exercises per each of the three workshop models is proposed for future research, after a larger scale study to support preliminary findings. This type of study, using a KTI third wave positive psychology approach with blended families including children, and in a live online format, in Canada and in the world, has never been carried out before. The applied KTI approach helps to integrate expert knowledge and needs from the blended family knowledge users. It may foster new meaning or understanding, or at least deeper collaboration between experts and blended families. In particular, the current research may shed a new light in blended family therapy research and blended family psychoeducational programs as blended families are fast becoming the most predominant form of family in Western society
Establishing a Zebrafish Cutaneous T-Cell Lymphoma Therapeutic Screening Platform
No full textCutaneous T-cell lymphoma (CTCL) is a rare non-Hodgkin’s lymphoma involving T-cells which home to the skin, with poor prognosis for advanced stages of disease. Due to complex genetics, epigenetics and environmental factors, the current in vitro and in vivo models have been limited in their ability to recapitulate and study the disease. To address this gap, a two-pronged approach to generate zebrafish models of CTCL was undertaken.
The larval zebrafish xenograft platform was optimized and employed using humanized GSS zebrafish larvae which express 3 human hematopoietic-specific cytokines (GM- CSF, SCF, SDF1α) to improve cancer cell engraftment. Following dose optimization of a number of agents and drug combinations, only combination vorinostat and gemcitabine showed a response in keeping with clinical responses observed in clinic, despite their typical use as monotherapies. A novel humanized, lymphoid-tailored zebrafish model expressing human IL-2, IL-5, IL-7, IL-15, DLL4, and SDF1α was also being generated to further improve lymphoid tumour engraftment in zebrafish larvae. Pilot studies using recombinant cytokines in vivo show promise using IL-2 and IL-15 for Hut78 cells xenografts, supporting the generation of these humanized zebrafish for future CTCL modelling.
In parallel, the first transgenic zebrafish model which expresses human STAT3, a key signaling molecule frequently amplified in CTCL pathogenesis, using the T-cell specific zebrafish lck promoter was generated. Early characterization confirmed successful expression of the transgene by qPCR, and RNA sequencing suggested differential gene expression in the transgenic larvae.
Together, these two systems represent the first zebrafish models of CTCL, establishing tools for further development to understand disease pathogenesis and evaluate drug responses in vivo
Impacts of an Electronic Medical Records System on Work Practices and Quality of Care at a Specialty Acute Care Hospital: A Mixed Methods Study
No full textBackground: Despite the increasing shift towards implementing hospital information systems (HISs), there is limited evidence of their effects as perceived by physicians following the use of longstanding implemented systems in specialty acute care hospitals, notably in Canada. Additionally, due to its burden on work practices, studies which assessed the impacts of implementations have shown limited or mixed findings on its ability to improve quality of care (QoC) (Tajirian et al., 2020; Trout et al., 2022; Campanella et al., 2016; Upadhyay & Hu, 2022; Price et al., 2022). In 2019, the University of Ottawa Heart Institute (UOHI) and five other Ottawa hospitals launched their use of Epic Systems. An initial pre-post study assessed the impacts of the implementation (Jaana et al., under review). This follow-up study aims to investigate physicians' perceptions of system use effects on work practices and QoC at the UOHI.
Methods: This study employed a sequential explanatory mixed methods design consisting of a survey distributed to physicians working at the UOHI, followed by semi-structured individual interviews with key physicians. Survey data were collected (n=31, response rate 42.5%) and analyzed to assess physicians' perceptions of system use, attributes and impacts on QoC, performing descriptive and bivariate analyses. 11 physicians were interviewed, and thematic analysis of transcripts identified six key aggregate dimensions.
Results: Physician survey respondents expressed dissatisfaction with system attributes such as functionality, information quality and support. Nevertheless, many expressed Epic's beneficial impact on several items related to care coordination, clinical documentation and clinical workflow efficiency. Some differences in perspectives were observed among groups with different tenure, age, specialty and biological sex. System feature use and satisfaction with system attributes were moderately associated with perceived improvements in documentation, care coordination and guideline adherence. Interviews' codes were aggregated into six dimensions (i.e., Use Behaviours, System Quality, Information Quality, Support Quality, User Satisfaction and Driving Improvements in QoC). These results complemented the quantitative findings and highlighted the poor alignment between system design and physicians' needs, inconsistent documentation practices and a lack of support for using Epic data in QI and research projects on QoC.
Conclusion: This mixed methods study provides a comprehensive assessment of how Epic system use influences QoC. Main findings reveal physicians' ability to navigate the system and access relevant and accurate patient information can affect the efficiency, effectiveness and safety of patient care. This study provides benchmarking of system use effects despite familiarity with Epic, informing future and ongoing implementation efforts in Canada. Improving system usability and providing transparent and sustained support to physician end users is critical. Furthermore, customization efforts need to be collaborative and tailored to subspecialty workflows, rather than relying on individual adaptations. This would promote standardized and complete data collection practices across the organization to further support physicians' medical decision-making capacity. Future studies should expand the scope of evaluation to include multiple sites using Epic and explore the experiences of various end-user groups
Quadrotor Tailsitter Scalability, Design, and Control: Towards Efficient Aerial Mobility
No full textThis thesis investigates the scalability, design, and control challenges of tailsitter unmanned aerial systems, which uniquely combine the vertical takeoff and landing capabilities of multirotors with the efficient forward flight characteristics of fixed-wing aircraft. In a tailsitter configuration, multiple rotors provide lift and control during hover that also generate thrust for forward flight, while fixed wings supply additional lift. The transition between hover and forward flight is achieved by rotating the entire vehicle about its pitch axis. The mode-switching operation introduces highly nonlinear dynamics, complicating efforts to accurately model, design, and control such vehicles. To address these challenges, this work develops empirical scalability laws derived from historical data, offering practical guidelines for component mass distribution, wing sizing, and performance estimation during the conceptual design phase of tailsitters. These principles are applied to the design of a 5 kg prototype, serving as a case study. Furthermore, a software-in-the-loop simulation is established to concurrently test the aircraft dynamics and the flight controller. Enhancements to the attitude controller are proposed to improve aircraft performance during the transition and forward flight, with a particular focus on mitigating oscillations in forward flight common to tailsitters with a single flight mode. The controller gains are adapted online using a fuzzy logic scheme based on measured error, error derivative, and aircraft pitch, resulting in improved responsiveness and stability as verified through simulation and test flights with the prototype aircraft. In summary, this thesis outlines empirical correlations for estimating preliminary design parameters of tailsitters and proposes a method to develop control algorithms for such vehicles
A Hybrid Modeling Workflow for Performing Finite Element Analyses Under In-Vivo Conditions
No full textComputational models are commonly used to evaluate spinal loads due to difficulties associated with acquiring in-vivo measurements. Musculoskeletal (MSK) models can be used for performing simulations of movement by considering active structures such as muscles and simplified representations of joint structures. Finite element (FE) models are rather actuated with simplified loading conditions determined from in vitro studies and consider detailed representations of tissues and joint structures, making them suitable to evaluate stresses and strains within the spine. This work was done in collaboration with Numalogics Inc., where a hybrid modeling workflow was developed to combine MSK and FE modeling methods to be able to evaluate stresses and strains within spinal instrumentation devices under the influence of in-vivo loading conditions, i.e., muscle forces. A previously validated fully articulated thoracolumbar spine MSK model was selected, simplified, and replicated exactly in Ansys, the FE modeling platform. The sensitivity of the compressive joint loads to the modifications brought to the original model was evaluated for static flexion poses. Then, two hybrid simulation workflows were developed. Version I consisted of performing a static optimization analysis using the MSK model to calculate muscle forces that satisfy equilibrium constraints. Version II consisted of performing a stability-constrained static optimization analysis to calculate muscle forces and stiffnesses that satisfy equilibrium and stability constraints in the MSK model. The forces and moments calculated from the MSK model were then transferred to the FE model as loading conditions. Validation studies were performed for both simulation workflows by comparing the kinematics and compressive joint loads in the MSK and FE models under identical loading conditions, for various static flexion poses and for six scaled models. Version I could not be validated due to convergence issues and large discrepancies between model outputs. Version II was successfully validated, with negligible kinematic and joint load differences between models across different ranges of motion. Very strong to perfect correlations were observed between model kinematics and joint loads, respectively, over all simulations performed. Overall, it was found that the consideration of stability constraints is essential for successfully performing FE analyses of the entire thoracolumbar spine under in-vivo loading conditions over physiological ranges of motion. In this work, no soft tissue deformations nor stresses were evaluated with the FE model. However, with the developed workflow, Numalogics will be equipped with a framework for their future works, including the comparison of stress distributions in spinal instrumentation devices when applying in vitro versus in-vivo loading conditions to their FE models
Exploring the Experiences and Perspectives of Care for Individuals with Posttraumatic Stress Disorder in Canada: A Multi-Methods Study
No full textObjectives: The aim of this study was to broadly explore Canadian adults’ experiences and perspectives of care for PTSD to generate insights and evidence from people with lived/living experience of PTSD care, with a focus on if PTSD care is meeting peoples’ needs and, if not, how supports, services, or practices could be improved to make care for PTSD more responsive.
Methods: We used a multi-methods, exploratory design, combining both quantitative and qualitative methods to better understand this highly complex phenomena. To address the overarching research questions, we designed the research with four components: a scoping review, a national snapshot survey, interviews with mental healthcare practitioners who have provided care to individuals with PTSD (“key informants”), and in-depth interviews with individuals with experiences and perspectives of care for PTSD (“participants”).
Results: The effects of trauma are vast and profound. Overall, peoples’ care needs are not being met and, currently, considerable inequity exists in the provision of and access to PTSD care. Further, we found a potential gap between the documented efficacy of currently recommended “evidence-based therapies” and what people with lived/living experiences of care for PTSD found helped them, or did not help them, in ameliorating or managing PTSD symptoms, or in their care journey.
Conclusions: Our results suggest that expanding and improving care options for individuals living with PTSD additional to psychological and psychiatric approaches is critical, as is addressing cost, stigma, and accessibility barriers to PTSD care. Equitable access to PTSD care will require leveraging current national efforts to ensure a collective understanding of trauma and its effects, and that supports and services are meeting the care needs of all impacted Canadians.
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Objectifs : L’objectif de cette étude était d'explorer de manière générale les expériences et les perspectives des adultes canadiens concernant les soins pour le SSPT afin de générer des informations et des preuves auprès de personnes ayant une expérience vécue ou en cours des soins du SSPT, en mettant l'accent sur la question de savoir si les soins du SSPT répondent aux besoins des gens et, si non, comment améliorer les soutiens, les services ou les pratiques pour rendre les soins liés au SSPT plus adaptés.
Méthodes : Nous avons utilisé une approche exploratoire à méthodes multiples, combinant des méthodes quantitatives et qualitatives pour mieux comprendre ce phénomène très complexe. Pour répondre aux questions principales de la recherche, nous avons conçu l’étude en quatre composantes : une revue de la portée, une enquête nationale instantanée, des entretiens avec des professionnels de la santé mentale ayant fourni des soins à des personnes atteintes du SSPT (les « informateurs clés ») et des entretiens approfondis avec les personnes ayant des expériences et des perspectives de soins pour le SSPT (les « participants »).
Résultats : Les effets du traumatisme sont vastes et profonds. Dans l’ensemble, les besoins des gens en matière de soins ne sont pas satisfaits etil existe actuellement des inégalités considérables dans la préstation et l’accès aux soins liés au SSPT. De plus, nous avons découvert un écart potentiel entre l’efficacité documentée des « thérapies fondées sur des données probantes » actuellement recommandées et ce que les personnes ayant vécu des expériences de soins pour le SSPT ont constaté qui les a aidées, ou non, à améliorer ou à gérer les symptômes du SSPT, ou dans leur parcours de soins.
Conclusions : Nos résultats suggèrent qu'il est essentiel d'élargir et d'améliorer les options de soins pour les personnes vivant avec le SSPT, en plus des approches psychologiques et psychiatriques, tout en s’attaquant aux obstacles liés au coût, à la stigmatisation et à l'accessibilité aux soins du SSPT. Pour assurer un accès équitable aux soins liés au SSPT, il faudra tirer parti des efforts nationaux actuels pour garantir une compréhension collective du traumatisme et de ses effets, et pour que les soutiens et les services répondent aux besoins de soins de tous les Canadiens touchés
Spatial and temporal variation of malaria incidence in children under 10 years in a pyrethroid-resistant vector area in southern Benin
No full textAbstract Background Spatial and temporal identification of malaria-endemic areas is a key component of vector-borne disease control. Strategies to target the most vulnerable populations, the periods of high transmission and the most affected geographical areas, should make vector-borne disease control and prevention programmes more cost-effective. The present study focuses on the spatial and temporal dynamics of malaria cases and the exogenous factors influencing the transmission in an area with pyrethroid-resistant mosquito vector populations. Methods A prospective cohort study of 1806 children under 10 years of age was conducted over 20 months to assess the risk of malaria incidence in the Cove-Zagnanado-Ouinhi (CoZO) health zone located in southern Benin. Childhood malaria data were used to identify malaria hotspots according to months of follow-up using spatial scanning methods based on the Kulldoff algorithm. Stability scores were calculated by season to assess incidence heterogeneity. Incidence values by month were aggregated with meteorological data; and demographic data were merged to detect cross-correlation between incidence and meteorological variables. Generalized equation estimators were chosen for their ability to handle intra-group correlation, ensuring robust and interpretable results despite the complexity of the data to identify factors explaining the spatio-temporal heterogeneity of malaria incidence in the CoZO health zone. Results Malaria incidence ranged from 1.41 (95% IC 0.96–2.08) to 13.91 (95% IC 12.22–15.84) cases per 100 child-months. Spatial heterogeneity in malaria transmission hotspots was observed over the study period, with relative risks ranging from 1.59 (p-value = 0.032) to 16.24 (p-value = 0.002). There was a significant negative association (correlation coefficient = − 0.56) between malaria incidence and temperature; and a slightly positive association (correlation coefficient = 0.58) between malaria incidence and rainfall. A significant association between malaria incidence with average house altitude (adjusted incidence rate ratio [aIRR] 1 (95% IC 0.99–1) P < 0.001), soil type aIRR 0.54 (0.39–0.75) p < 0.001 and temperature (incidence rate ratio [IRR] 0.69 (0.66–0.73) p < 0.001). Conclusion This study uses innovative technologies such as remote sensing and geographic information systems (GIS) to analyse the environmental, meteorological and geographical factors influencing malaria transmission, thereby identifying high-risk areas and associated factors. It demonstrates that these tools improve the accuracy of control strategies, while highlighting the crucial role of the environment and human behaviour, paving the way for more targeted interventions against malaria and other vector-borne diseases