VictorJuiz/thesis huggingface dataset:
Use of Troponin Testing after Non-cardiac Surgery
Keywords: Guideline
MINS
Myocardial injury after noncardiac surgery
noncardiac surgery
Revised cardiac risk index
Troponin

Myocardial injury after noncardiac surgery (MINS), which is most often asymptomatic, is associated with increased mortality and morbidity. In 2017, the Canadian Cardiovascular Society (CCS) published guidelines recommending broad post-operative troponin surveillance in high-risk patients having major non-cardiac surgery. The objectives of this thesis were to: (1) evaluate the proportion of patients having major non-cardiac surgery in Ontario that would meet guideline recommendations for routine post-operative troponin testing; (2) determine the patient-, surgical-, and hospital-factors associated with post-operative troponin testing; and (3) evaluate whether high-intensity troponin testing practices at the hospital-level were associated with fewer adverse outcomes after major non-cardiac surgery. In Chapter 2, I identified 257,704 patients who underwent non-cardiac surgery in Ontario. Applying the CCS guidelines to this cohort, 71.2% of elective surgery patients and 81.0% of urgent surgery patients would have met recommendations for post-operative troponin screening, while only 10.8% and 27.1% of guideline recommended patients received post-operative troponin testing, respectively. In Chapter 3, I identified 176,454 patients undergoing orthopedic, colorectal, or vascular surgery in Ontario. Hierarchical logistic regression modeling was used to assess the association of patient-, surgery-, and hospital-factors with postoperative troponin testing. I found that troponin testing varied substantially across hospitals for selected major non-cardiac surgery procedures even after accounting for differences in patient-level cardiac risk factors. In Chapter 4, I identified 18,467 patients undergoing common vascular surgical procedures (carotid endarterectomies and abdominal aortic aneurysm repairs). Cox proportional hazards modeling was used to assess the association of hospital-specific testing intensity with 30-day and 1-year major adverse cardiovascular outcomes (MACE). Compared to patients at low-testing intensity hospitals, patients at high-testing intensity hospitals experienced a lower hazard of MACE over 30-days and 1-year. Overall, I established that CCS guidelines recommend routine troponin testing for most patients having major non-cardiac surgery. Prior to the publication of the CCS perioperative guidelines, the overall testing rate was low, and there was substantial hospital-level variation in the use of routine troponin testing. Finally, in a cohort of vascular surgery patients, I found that patients who had procedures at high-testing intensity hospitals experienced fewer adverse outcomes, thus supporting recommendations to increase testing to detect MINS in the future.
Selection and Evolutionary Constraint in Ipomoea hederacea
Keywords: G-matrix
Genetic correlations
Natural selection
Quantitative genetics

Understanding how adaptive evolution proceeds in populations experiencing different environments is the basis of much of evolutionary biology. Genetic variation is required for evolutionary change by natural selection to occur, and that genetic variation is oftentimes correlated among traits. Selection acts on the entirety of an organism’s phenotype and is thusalso best considered in a multivariate context. The interaction between selection and the organization of genetic variation together produces the evolutionary trajectory of a population. In my doctoral work, I have explored the influence of genetic correlations between traits on the response of populations to selection in populations across a geographic range, using the Ivyleaf Morning Glory (Ipomoea hederacea). I demonstrate the constancy of these genetic correlations among populations in the face of the destabilizing force of genetic drift. I investigate how genetic correlations and strong natural selection have shaped divergence among populations across space. Additionally, I consider what these evolutionary patterns suggest about the maintenance of range limits and potential for future northward expansion of Ipomoea hederacea. I find overall stability of the genetic relationships among quantitative traits, and strong selection which acts counter to the majority of the genetic variation. The observed divergence among populations has occurred despite the constraining influence of their quantitative genetic architecture. Future adaptive evolution beyond the range margin will largely depend on the source population, as minor difference in the structure and quantity of genetic variation may have critical impact of population persistence. Further, I demonstrate the potential for using machine learning to predict fitness using gene expression data from a field experiment with I. hederacea. I find that photosynthesis-related genes, and genes related to stress response are major contributors to fitness differences.
Finding Oneself in the World
Keywords: First-person perspective
Inquiry
Objectivity
Presence
Subject of experience
Third-person perspective

Thinking about oneself as the subject of a perspective on the world leaves unanswered fundamental questions about one’s identity as an object in the world: about which thing one is, what kind of thing one is, and about whether one exists as an object at all. I put forward a new way of thinking about these questions by outlining the subject-as-object problem, a problem for any attempt to adopt a third-person perspective on oneself qua subject. I argue that the source of the problem lies in the relationship between a basic precondition for inquiry – that something be present – and a framework that enables us to conceive of ourselves as inquirers in an objective world – the framework of objectivity. Once the problem is recognized, we can explain why it is possible to raise questions about one’s identity in response to any account of oneself and one’s relation to the world. Furthermore, having the problem in view enables us to more deeply engage with a range of philosophical issues that concern, in one way or another, the relationship between the subject’s perspective and the objective circumstances under which this perspective discloses a part of the world.
Improvements to Digital Microfluidic Technologies: Towards Automated Point-of-Care Diagnostics
Keywords: biofouling
COVID19
digital microfluidics
disease diagnosis
nucleic acid amplification assay
supercritical angle fluorescence spectroscopy

Digital microfluidics (DMF) is a liquid handing technique that allows precise manipulation of discrete droplets of liquids by electrostatic forces. Individual droplets can be dispensed, mixed, merged, and separated in DMF, allowing automation of liquid handling steps that are required in complex multi-step operations. This automation capability makes DMF an attractive candidate for developing point-of-care (POC) systems with minimal user involvement and training. However, the biofluids that are commonly handled by POC systems can negatively impact droplet movement in DMF through non-specific adsorption (NSA) to the device surfaces; thus, there are substantial challenges that must be overcome before this dream can be realized. This thesis describes my work investigating Pluronic®/Tetronic® surfactants in combatting NSA in DMF to enable automated sample processing in POC systems. Chapter 2 describes a systematic study of the anti-fouling performance and mechanism of a series of Pluronic® and Tetronic® surfactant additives. Chapter 3 describes the development of a novel microscopic technique, supercritical angle fluorescence microscopy, for monitoring surface adsorption on a Teflon-AF film and determining the anti-fouling mechanism of surfactant additives. Chapter 4 describes the hardware and methodological improvements that enable viral nucleic acid extraction and amplification in DMF for detecting infection for Zika virus in a field trial in Recife, Brazil. Chapter 5 describes work-in-progress towards the application of DMF with surfactant additives for a new type of portable SARS-CoV-2 nucleic acid-based diagnostic technique. In summary, this thesis addressed the challenges of NSA in DMF and describes how to push the boundaries of what is possible for DMF in automating liquid handling in POC systems.
Reconstructing Past Sea Ice Cover with Coralline Red Algae
Keywords: Arctic
Coralline red algae
Crossdating
Mg/Ca
Paleoclimate
Sea ice

Arctic sea ice plays a pivotal role in climate regulation. Its decline in recent decades has contributed to Arctic Amplification, the fast rate of Arctic warming in comparison to other regions. Models that aim to predict future climate are continuously under development as they still underestimate warming, and particularly sea ice loss and variability. These models must be refined with long-term, spatially diverse, and highly resolved data, to be as accurate as possible. However, instrumental data records are short-term and spatially constrained. The use and continued development of environmental proxies such as sediment and ice cores help lengthen data records (Chapter 1). Likewise, the coralline red algae species Clathromorphum compactum is a sea ice cover proxy in development. Several multi-century algal timeseries of past sea ice variability have been generated using this proxy, however, uncertainties remain about: 1) whether sea ice cover can be reconstructed at all C. compactum collection sites, and 2) whether methodological standardization ensure data replicability between intra-site specimens and validate C. compactum-based chronologies. In this thesis, I first tested whether growth increments, Mg/Ca averages, or combined anomalies were best suited to capture sea ice variability during the ~40-year satellite record at 11 subarctic and arctic sites (Chapter 2). Results showed that growth increment-based chronologies from exposed sites, far from runoff sources, experiencing long lasting sea ice cover (>6-7 months) best captured sea ice variability. However, intra-site replicability was low and insignificant at most sites in this multi-site study. This prompted a study on the application of dendrochronological crossdating methods to improve intra-site replicability of algal chronologies (Chapter 3). The findings suggested that the previously utilized methods incorporated subjective interpretation and that crossdating improved intra- and inter-specimen replicability, setting a new standardized methodology for age model determination and validation. Validated algal chronologies were then used to study the relationship between sea ice and large-scale atmospheric patterns and showed a significant sea ice response to the Arctic Oscillation and other atmospheric patterns (Chapter 4). This thesis has examined the advantages and limitations of the algal sea ice proxy and should methodologically guide future research with C. compactum-based proxies.
The Canadian Punitive Paradox: The Evolution of Conservative Political Marketing Practices and the Late Onset of Penal Populism in Canadian Federal Politics
Keywords: Emotionality
Penal populism
Political Marketing
Sentencing Policy

At the height of the punitive turn that occurred among Western liberal democracies, Canadian federal politics stands out as exceptional for choosing not to embrace a ‘tough-on-crime’ agenda. Instead, penal populism emerged as a salient political marketing tool in Canadian federal politics much later — at a time when many of the failures associated with its outcomes were coming to light elsewhere. The latent emergence of penal populism in Canadian federal politics was atypical as it often surfaced as a hollow performative tool that consisted of expressive rhetoric over substantive outcomes. This dissertation argues that the political marketing strategies that governed political campaigns were critical in the decision to adopt or reject penal populism as a campaign tool. By situating the presence or absence of penal populism within the context of shifting campaign strategies, this study deepens our understanding of Canadian punitive exceptionalism and shows that the Canadian version of penal populism was heavily influenced by advancements in political marketing strategies. This study also advances our understanding of the narratives used to shape a ‘tough-on-crime’ image and the extent to which it existed between electorally successful conservative campaigns. Through an analysis of the emotional rhetoric used to promote punitive sentencing policy, specifically mandatory minimum and maximum sentences, this dissertation exposes the manner in which emotionality is used to enhance the appeal of these political offerings.
A Thermosensitive Liposome Formulation of Vinorelbine for the Treatment of Recurrent Rhabdomyosarcoma
Keywords: Drug Delivery
Mild Hyperthermia
Rhabdomyosarcoma
Thermosensitive Liposome
Vinorelbine

Approximately one third of rhabdomyosarcoma (RMS) patients experience disease recurrence and subsequently face a dismal prognosis. In most cases, the disease recurrence involves or is confined to the primary disease site, highlighting the need for effective treatment approaches that can improve local control. Chemotherapy continues to play an important role in treating residual disease and preventing local recurrence but is often associated with severe adverse effects. Common strategies to improve efficacy and toxicity profiles of chemotherapy, including liposomal encapsulation, heavily rely on passive tumor targeting via the enhanced permeability and retention (EPR) effect. Due to the recognized heterogeneity associated with the EPR effect in humans, other approaches for achieving tumor targeted drug delivery are needed. This thesis aims (1) to develop a thermosensitive-liposome formulation of vinorelbine (ThermoVRL) to provide EPR-independent drug delivery targeted to the tumor, (2) to evaluate the therapeutic efficacy of ThermoVRL in combination with localized mild hyperthermia (HT) compared to treatment with a non-thermosensitive liposomal formulation of vinorelbine (NTSL-VRL) in murine models of RMS and to identify the underlying pharmacokinetics and biodistribution, and (3) to determine the therapeutic efficacy of ThermoVRL and HT in an immunocompetent model of RMS and to explore if the addition of immunotherapy (i.e., immune checkpoint inhibition therapy (ICI)) to this treatment approach can enhance systemic anti-tumor effects. In summary, this work successfully developed a ThermoVRL formulation. Treatment with ThermoVRL and HT afforded superior therapeutic efficacy relative to treatment with free drug in a mouse xenograft model of RMS. Importantly, pharmacokinetic and biodistribution assessments of vinorelbine revealed an increase in tumor specific drug delivery when administered as ThermoVRL compared to administration as NTSL-VRL. Studies employing a bilateral RMS tumor model in immunocompetent mice revealed that anti-tumor effects following treatment with ThermoVRL and HT remain largely localized to the primary tumor site. However, the addition of ICI significantly enhanced the systemic treatment effects of ThermoVRL in combination with HT. The results of these studies demonstrate that this delivery approach can confer targetability to an untargeted drug molecule and open the door to treatment combinations with ICI to enhance the systemic treatment capabilities of thermosensitive liposomes.
Loss of Capacity to Consent and Access to Medical Assistance in Dying: Healthcare Providers’ Experiences and Perspectives
Keywords: Decision-making capacity
End-of-life care
Medical assistance in dying
Moral agency
Palliative care
Relational autonomy

Under Bill C-14, patients who met eligibility requirements were prevented from accessing medical assistance in dying (MAiD) if they lost decision-making capacity while awaiting MAiD. Little is known about healthcare providers’ experiences of patients’ loss of capacity to consent and subsequent ineligibility for MAiD. The enactment of Bill C-7 in 2021 has allowed eligible patients to use a waiver of final consent agreement to access MAiD following their loss of capacity, but healthcare providers’ perspectives on providing MAiD using the proposed amendments were not known. Therefore, the aims of this study were: 1) to explore Canadian healthcare providers’ perspectives on providing MAiD to eligible patients in the absence of a contemporaneous final consent; and 2) to explore healthcare providers’ experiences when their previously eligible patients were unable to access MAID due to a loss of capacity to consent. A critical qualitative methodology, informed by feminist ethics, was used focusing on the concepts of power, relationality, and moral agency. A voice-centred relational approach was used for data analysis. Semi-structured interviews were conducted with a heterogenous sample of 30 participants, (physicians, nurses, nurse practitioners and social workers) recruited using purposeful and snowball methods, who had experiences with patients’ loss of capacity and subsequent ineligibility for MAiD. The findings highlight that healthcare providers’ agency and experiences with MAiD were influenced by socio-political, personal, and professional factors, that in turn, had significant impact on their patients’ access to and experiences with MAiD. While participants morally supported the amendment to waive the final consent requirement, they anticipated ethical and legal challenges in the absence of patients’ contemporaneous consent. The study identifies gaps in the care and support offered to patients and families following patients’ capacity loss and subsequent ineligibility for MAiD. The inconsistencies and disparities in the access to MAiD and other end-of-life services across Canada also came to light. Organizational and professional support, adequate resources, and infrastructure as well as clear policies and guidelines are required to prevent capacity loss-related ineligibility for MAiD, to improve end-of-life care for incapacitated patients and their families, and to promote the safety and well-being of healthcare providers.
Resilience among Newcomer Students in Canada: A Transformative and Socio-Ecological Analysis of Narratives from Tree of Life Workshops
Keywords: Culture
Narrative
Newcomer Students
Resilience
Transformative Paradigm
Tree of Life

Newcomer students’ adaptation is a major concern for Canadian educators and teachers due to the recent influx of refugees and immigrants resulting from political, social, and natural displacement. Intersections of race, gender, language, low SES, and previous traumas have traditionally motivated researchers and policymakers to focus mostly on language, mental health symptomology, and risk assessment among this population. Consequently, in institutional programming (e.g., schooling, community organizations, government welcome programs), overemphasizing risk factors has created a deficit-oriented approach in which newcomer students are viewed as the victims and passive recipients of services. However, to create an empowering post-migration experience, it is crucial to understand how newcomer students view themselves, navigate their resources, and make sense of their experience.This case study’s narrative and transformative stance enabled: 1. Shedding light on the less heard stories of the newcomer students and highlighting the risk and resources identified by the newcomers themselves; 2. Examining the influence of participation in a strength-based workshop where the newcomer students’ agency was encouraged. The main evidence of this study was collected through a narrative activity called Tree of Life for 8 weeks with 3 groups of students in two schools within the Greater Toronto Area (GTA). The influence of the workshop was studied via facilitator’s observations, teachers’ reflections, and the students’ post-workshop interviews. Findings of this study revealed the holistic understanding of the newcomer students about their pre- and post-migration experience, how cultural background and past experiences as well as their hopes for the future can be a source of strength, and how the schools’ attitude about newcomers can influence the students’ post-migration experience. The positive feedback and outcomes of the workshop call for participatory and culturally relevant programs for newcomer students where they feel safe and have the chance to know themselves, build their new identity, and create community. Similar programs are especially recommended for students of refugee background who have faced significant interruption in their schooling, where the intersection of past traumas, present stigmatization, and socioeconomic status has influenced their schooling experience and self-image. Keywords: newcomer students, resilience, transformative paradigm, narrative, culture, socio-ecological approach, strength-based approach.
From Suicidality to Psychological Growth: Understanding the Role of Affective Processing and Meaning Making
Keywords: Affect
Emotional Processing
Psychological Growth
Spirituality
Suicidality
Wisdom

Difficult life situations are deemed to facilitate the cultivation of an array of positive changes, collectively referred to as growth through adversity (GTA). Whereas some investigations have documented GTA in survivors of those who have died by suicide, there are scant data regarding the possibility of psychological growth in the aftermath of resolved suicidality for individuals with lived experience of suicidality. In addition, the mechanism through which individuals resolve suicidality and potentially cultivate positive change is unclear. A rarely examined pathway to explain positive change is a shift in individuals’ emotion system. This is rooted in the theory that deep and lasting change cannot occur without a change in one’s affective experiences. Therefore, the current study aimed to examine affective processing (AP) before, during and after suicidality with the aim of understanding whether participants' interactions with affects and emotions could play a role in the resolution of active suicidality. Moreover, this study examined the often overlooked externally determined protective and risk factors as potential contributors to suicidality, to better contextualize the findings. The results of a thematic analysis of in-depth interviews with 14 participants indicated that AP was implicated in the process. In particular, participants' difficulty with processing affects was prominent during the active phase of suicidality and remarkably improved in the process of moving away from suicidality. These changes appeared closely associated with the balance between risk and protective factors, in the sense that highly demanding circumstances stifled, whereas supporting situations facilitated AP. Finally, participants’ narratives indicated the occurrence of GTA reflected in multiple aspects of wisdom such as balanced self-appraisal and prosocial orientation. There were also indications of a renewed interest and increased affinity for spirituality.