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Characterizing Survival and Treatment in Synchronous Intracranial Metastases: The Influence of Extracranial Disease
Get PDFCancer patients with synchronous intracranial metastatic disease (IMD) represent a heterogeneous population with varied outcomes. We conducted a retrospective, population-based study of 6,069 patients with sIMD in Ontario, Canada, from 2010–2019, to compare clinical characteristics, treatment patterns, and overall survival (OS) between those with isolated IMD (i-sIMD) and those with extracranial metastases and sIMD (sIMD+ECM) at cancer diagnosis. I-sIMD occurred in 397 (6.9%) patients and was associated with a higher proportion of breast primary cancers, greater comorbidity, and more frequent systemic anti-cancer therapy use. Surprisingly, these patients were less likely to receive stereotactic radiosurgery (SRS) or neurosurgical resection. Regardless, i-sIMD was associated with longer OS than sIMD (5.4 vs. 3.0 months; adjusted HR 0.53; p<0.001), particularly among patients treated with SRS or neurosurgery (20.5 vs. 9.2 months; p<0.001) and patients with breast cancer compared to other solid tumours (20.8 vs. 2.3 months; aHR 0.47; p=0.002). Our findings highlight i-sIMD as a distinct subgroup with more favourable outcomes.M.Sc
An online low-FODMAP educational intervention improves physical and psychological symptoms of irritable bowel syndrome
Get PDFThe low Fermentable Oligo-, Di- and Monosaccharides, And Polyols (FODMAP) diet has proven beneficial for the management of irritable bowel syndrome (IBS). The growing demand and limited availability of registered dietitian specialized in IBS together with the omnipresence of technology in daily life, provides an opportunity for the development of adapted resources. This study aimed to assess the impact of implementing the low FODMAP diet, through an online educational service platform, on the quality of life of patients living with IBS. A prospective single-group intervention pilot study involving patients with IBS from two hospitals was conducted. Participants followed the low-FODMAP diet using a web-based platform for 6 months. The IBS quality of life questionnaire (IBS-QoL), the IBS symptom severity scoring system (IBS-SSS) and the State-Trait Anxiety Inventory Form Y (STAI) were completed at baseline, after the restriction phase and after reintroduction of tolerated FODMAPs. Fifteen of the 35 participants completed the study (80.0% female, median age of 43.0 (36.0-52.0) years) and at 6 months, a trend towards IBS-QoL improvement was observed, along with a significant improvement in IBS-SSS (from 276 to 200; pThe presentation of the authors' names and (or) special characters in the title of the pdf file of the accepted manuscript may differ slightly from what is displayed on the item page. The information in the pdf file of the accepted manuscript reflects the original submission by the author
Thinking as a Mere Citizen of the World: Kantian Morality in a Pluralist Frame
Get PDFThis dissertation argues that Kantian morality is more compatible with cultural pluralism than has thus far been acknowledged. Cultural pluralism denotes a normative commitment to the idea that we ought to uphold diversity and protect the rights of individuals within a given society to hold a multiplicity of divergent views, beliefs, and values. I argue that cultural pluralism should also be understood as being invested in certain basic liberal values and a concern for protecting fundamental human rights. As such, the pluralist needs a moral theory that balances the commitment to protecting diversity with the commitment to protecting human rights and provides a way of determining the appropriate limits of toleration. While moral relativism can be seen as a natural entailment of cultural pluralism, the kind of moral theory that the pluralist needs cannot be provided by relativism. I argue that there is good reason for the cultural pluralist to consider Kantian morality as a viable and compelling alternative. I do so by developing and clarifying elements of Kant’s thought which are often mischaracterized, oversimplified, or overlooked when discussing his moral theory, including egoism, broad-mindedness, the relationship between culture and practical judgment, and the importance of community in our moral lives. I attend to these elements with the dual aim of clarifying what Kant's position is and exploring which entailments might reasonably be drawn from his thought and developed further. In contrast with many stereotypical views of Kant’s moral system, I hold that his approach balances objectivity of principles with an awareness of the complexity of the historically located and socially embedded subject who makes moral judgments. I conclude by arguing that, while the two positions do not perfectly converge, Kantian morality and cultural pluralism stand much more closely to one another than has been imagined.Ph.D
Prevalence, Geographic Variations, and Determinants of Pain Among Older Adults in China: Findings from the National Urban and Rural Elderly Population (UREP) Survey
Get PDFObjectives: This study aimed to reveal the prevalence, geographic variations, and determinants of pain among the Chinese older adult population and provide empirical strategies for pain management in older adults in China. Methods: A total of 21,346 Chinese residents aged ≥ 60 years from 31 provinces in mainland China participated in our survey. Standardized questionnaires were used to collect data on socioeconomic characteristics, lifestyle factors, and self-reported pain experiences. Multivariate logistic regression models were used to estimate the associations between individual socioeconomic status, chronic diseases, and pain. Results: The national prevalence of pain was 56.5% (95% CI: 55.9–57.1%), representing approximately 140 million Chinese older adults. The prevalence increased with aging and peaked at 80 years and older (61.00%, 95% CI: 59.30–62.70%). Women (62.36%, 95% CI: 61.47–63.25%), rural residents (61.27%, 95% CI: 60.34–62.20%), and those with no formal education (65.08%, 63.90–66.26%) had a higher prevalence than men (50.27%, 95% CI: 49.32–51.22%), urban residents (52.19%, 95% CI: 51.28–53.10%), and those with higher education levels, respectively. Provincial prevalence ranged from 38.98% in Shanghai to 72.75% in Gansu Province. The presence of chronic diseases significantly increased the odds of pain, with multimorbidity (three or more chronic diseases) showing the strongest association (OR = 11.380, 95% CI: 10.257–12.627). Conclusions and Implications: Pain was highly prevalent among older adults in China and varied geographically. Socioeconomic status, chronic diseases, and multimorbidity were strongly associated with pain prevalence. Our findings support prioritizing the reduction in gender and geographic disparities in China’s pain management strategies. An integrated approach addressing both pain and chronic diseases should be urgently established in China’s healthcare system for older adults
Repeatability of Whole-Building Airtightness Testing in a Residential Wood-Framed Building Under Varying Weather Conditions
Get PDFThis study investigates the repeatability of whole-building airtightness testing under varying weather conditions in a two-story, wood-framed residential building with an enclosure volume of 818 m³ and an area of 532 m², located in Victoria, Canada, situated in Climatic Zone 4C (Marine), characterized by mild, wet winters and cool summers. Air leakage tests, performed in accordance with ASTM E779, were conducted using blower door pressurization and depressurization methods. Weather variables recorded during testing included wind speed (2–14 km/h), indoor (17–23°C) and outdoor (5–16°C) temperatures, and relative humidity (indoor: 34–59%; outdoor: 46–96%). Regression analysis revealed no significant correlation between weather variability and airtightness metrics. Depressurization tests consistently demonstrated more airtight results compared to pressurization. These findings reinforce that blower door testing results are repeatable and reliable despite weather fluctuations, validating the applicability of single-event airtightness tests for evaluating building envelopes.The presentation of the authors' names and (or) special characters in the title of the pdf file of the accepted manuscript may differ slightly from what is displayed on the item page. The information in the pdf file of the accepted manuscript reflects the original submission by the author
An Exploratory Investigation of Trait Anhedonia and Its Correlates Across the Schizophrenia Spectrum
No full textAnhedonia, the reduced capacity to experience pleasure, has long been considered a core negative symptom of schizophrenia. However, while people with schizophrenia consistently report anhedonia on trait questionnaires, they also consistently report intact state pleasure relative to healthy controls. Several theories have been proposed to reconcile this apparent paradox within the schizophrenia literature. Recent work grounded in the evaluative space model, a theory of the motivational underpinnings of the positive and negative emotional valence systems, is showing promise in better understanding state-trait discrepancies in this population.
The current dissertation includes four studies designed to better understand, and improve the convergent validity between, state and trait pleasure assessments in people with schizophrenia. Study 1 is a systematic review and meta-analysis of 146 studies showing that samples of people with schizophrenia ubiquitously report elevated trait anhedonia relative to healthy controls. Moderator analyses showed that clinical and demographic characteristics weakly predicted trait anhedonia effect sizes. Using Exploratory Structural Equation Modelling (ESEM) in 2250 Canadian and American Prolific volunteers, Study 2 refined existing items from trait anhedonia measures identified in Study 1 and validated them against positive and negative response tendencies to develop a trait anhedonia measure grounded in the evaluative space model. It also showed measurement invariance across differing scale types, sex, age, and positive schizotypal personality features. Using a multi-trait multi-method ESEM approach in 1305 Prolific volunteers, Study 3 showed that the refined measure of trait anhedonia is moderately correlated with state pleasure using stimuli from the International Affective Picture System, suggesting that state and trait anhedonia are related but not equivalent constructs. Finally, Study 4 tested the validity of the refined measure of trait anhedonia in 50 people with schizophrenia and 48 community controls. Although state-trait discrepancies remained using a previously validated measure of trait anhedonia, there were no significant between-group differences in state or trait anhedonia using the refined measure. Moreover, coactivation of state positive and negative emotions significantly predicted trait anhedonia. Based on these results, candidate mechanisms for trait anhedonia in schizophrenia and associated treatment considerations are discussed, including emotional ambivalence, biased expectations and beliefs, shifting values, and neurocognition.Ph.D
Patient Experience and Perceived Supportive Care Needs of Adults with Relapsed/Refractory Acute Leukemia
Get PDFAcute leukemia (AL) is an aggressive cancer of the blood and bone marrow that isdiagnosed suddenly, carries a high symptom burden, and requires complex medical management.
Relapsed and/or refractory (RR) disease is a common outcome in adults with AL, further
complicating prognostication and treatment decision-making and contributing to high mortality.
Patients with RR AL have high rates of acute care utilization, receive systemic therapy in the
final month of life, and die in hospital, frequently with late or absent referral to palliative care,
trends that suggest deficiencies in the quality of care. Despite these circumstances, little is known
about the experiences and perceived supportive care needs of adults with RR AL.
The purpose of this dissertation was to address this knowledge gap by exploring the
patient experience and supportive care needs of adults with RR AL through a qualitatively driven
mixed methods approach. This thesis was guided by a pragmatic philosophy and nursing’s
epistemological stance. A scoping review, identified knowledge gaps in the literature on patient
experience and care in advanced AL, highlighting barriers to shared decision-making, advance
care planning, and timely provision of psychosocial support. The study that followed the review
included semi-structured interviews with adults living with RR AL, supplemented by validated
patient-reported outcome measures.
Findings demonstrated patients’ reliance on their hematology team, coupled with efforts
to preserve agency amid treatment uncertainty and urgency. The illness disrupted identity,
magnified relational dynamics, and reduced functional capacity, particularly for older adults.
Participants drew on faith or biomedical expertise to sustain hope, finding meaning through
treatment and adopting a present-focused outlook. Supportive care needs data revealed a desire
for information delivered empathically and directly, with unmet needs centering on
psychological well-being, relational support, functional capacity, and self-management
resources.
This dissertation provides an integrated, patient-reported account of living with RR AL,
revealing not only disease-specific challenges but also distinct informational, psychosocial, and
relational needs. The findings demonstrate the feasibility and value of engaging this medically
fragile population directly and provide actionable insights to guide supportive care practice and
research.D.N
Understanding the Role of Large Language Model Virtual Patients in Developing Communication and Clinical Skills in Undergraduate Medical Education
Get PDFAccess to practice opportunities for history-taking in undergraduate medical education can be resource-limited. Large language models are a potential avenue to address this. This study sought to characterize changes in learner self-reported confidence with history-taking before and after a simulation with an LLM-based patient and understand learner experience with and the acceptability of virtual LLM-based patients. This was a multi-method study conducted at McMaster University. Simulations were facilitated with the OSCEai tool. Data was collected through surveys with a Likert scale and open-ended questions and semi-structured interviews. A total of 24 participants generated 93 survey responses and 17 interviews. Overall, participants reported a 14.6% increase in comfort with history-taking. Strengths included its flexibility, accessibility, detailed feedback, and ability to provide a judgement-free space to practice. Limitations included its lower fidelity compared to standardized patients and at times repetitive and less clinically relevant feedback as compared to preceptors. It was overall viewed best as a supplement rather than a replacement for standardized patients. In conclusion, LLM-based virtual patients were feasible and valued as an adjunct tool. They can support scalable, personalized practice. Future work is needed to understand objective metrics of improvement and to design curricular strategies for integration
Developmental trajectories predictive of stillbirth in a longitudinal mouse model of fetal growth restriction
Get PDFFetal growth restriction (FGR) secondary to placental insufficiency often leads to morbidity and mortality in the perinatal period.Fetal adaptations such as “brain sparing” blood flow redistribution offer some protection, but predicting whether a fetus in thisstate will survive is challenging. The goal of this research was to identify vascular responses predictive of stillbirth or hypoxia based on serial Doppler ultrasound measurement in a mouse model of FGR. We performed serial Doppler ultrasound observations of fetal blood flow redistribution in a murine model of FGR, where prolongation of pregnancy was induced pharmacologically with progesterone in 56 CD-1 mice. Observations were made at E18.5 (physiologic term), E19.5 (term þ 1), and E20.5 (termþ 2). Flow velocity waveforms were obtained from the middle cerebral artery (MCA), ductus arteriosus (DA), main pulmonary artery (MPA), ductus venosus (DV), umbilical artery (UA), and umbilical vein (UV). Following euthanasia, pimonidazole immunohistochemistry quantified tissue hypoxia. Among 56 pregnancies, the strongest predictor of stillbirth was low DA peak systolic velocity at E19.5 (<217 mm/s, p=0.021, R2=0.52). Among survivors, cerebral hypoxia was predicted by elevated MCA peak systolic (>26.6 mm/s, p=0.022, R2=0.59) and end-diastolic velocity (>10.1 mm/s, p=0.043, R2=0.53, whereas high MPA flow (>0.73 mL/min, p=0.029, R2=0.51) predicted hepatic hypoxia. Overall, fetuses with a weaker pulmonary blood flow redistribution response were found to have worse outcomes, despite cerebral vasodilation. This minimally invasive murine model offers valuable insights into this pathophysiology of FGR-related stillbirth and highlights the prognostic potential of assessing fetal brain flow and pulmonary perfusion in tandem during sonographic surveillance of high-risk pregnancies.This work was supported by Canadian Institutes of Health Research Grant 153202 (to J.G.S., C.K.M., and J.K.) and Grant 169050 (to J.G.S., C.K.M., J.K., and M.S.). SickKids Research—Restracomp PhD Scholarship (to A.S.). Canada Research Chair in Biomedical Imaging (to J.G.S.)
Data-Driven 3D Modeling via Assembly, Generation and Detailization
No full textIn this thesis, we present algorithms for 3D shape creation, addressing two key challenges: assembling a 3D shape from a set of fractures and refining the geometric details of a coarse shape given by users.
The first part of the thesis is focused on the problem of 3D shape assembly from a pair or a set of fractures. Existing 3D shape assembly methods rely heavily on recognizing the semantics of object parts (e.g., identifying a chair's leg). However, semantic information is not always well-defined or even available in shape assembly settings. For instance, objects that break naturally due to external forces generally do not break into fragments that are semantically well-defined. The reliance on semantic information makes these methods hard to scale and difficult to generalize. To overcome these challenges, we propose a pairwise geometric shape assembly algorithm, which achieves shape assembly by reasoning about the geometric fit between shapes. We demonstrate that the proposed algorithm can be applied to the two-part geometric shape assembly task, which can be seen as an integral subroutine in the broader problem of multi-part geometric shape assembly. We also study the multi-part geometric shape assembly problem by collecting a large-scale fractured object dataset and benchmarking several state-of-the-art shape assembly algorithms on our dataset.
The second part of the thesis is focused on creating a 3D shape by refining the geometric detail of an input coarse shape. We first present an encoder-decoder neural net, which learns a compressed, progressive representation for an input shape. The resulting neural net can not only learn level-of-detail representations for an input shape but can also be used for mesh compression and transmission applications. We also propose a framework that allows users to create a shape with rich geometric details through a text prompt and an input coarse shape. This framework allows users to control the coarse structure (pose) of the output shape through the input coarse shape and the local geometric details through the input text prompt.
Both parts of the thesis can be used to support interactive 3D modeling pipelines.Ph.D