Lakehead University Knowledge Commons

Knowledge Commons is an open access repository for scholarship and research produced at Lakehead University. It is a free and secure repository for LU faculty, students, staff, and researchers to preserve and present their scholarship.

Communities in KnowledgeCommons

Select a community to browse its collections.

Now showing 1 - 3 of 3

Recent Submissions

The effect of trait victimhood on perceptions of, and responses to, interpersonal stress and trauma: a daily diary and cross-sectional evaluation
(2026) MacIsaac, Angela; Mushquash, Aislin; Visser, Beth; Kim, James; Scott, Katreena
The tendency for interpersonal victimhood (TIV) denotes a disposition to see oneself as a victim across interpersonal relationships. Individuals who score highly on this construct tend to ruminate on perceived offenses and be generally distrusting. There is a dearth of research, however, on the relationship between TIV and the real-word experience and perception of interpersonal events. This includes both large, impactful life events like trauma, and more minor everyday interpersonal stress. To fill this gap, in one study (Trauma Study), 400 participants recruited from Prolific completed measures of TIV, childhood maltreatment and lifetime trauma, posttraumatic cognitions, and an evaluation of trauma concept breadth. In a second study (Daily Stress Study), 447 undergraduate students completed a two-week daily diary study measuring the occurrence of interpersonal stressors, rumination, and perceived stress, as well as participants’ predictions and recollections regarding stressors. Across both studies, retrospective report of childhood maltreatment positively predicted TIV, but paradoxically, minimization of this maltreatment was also a significant, positive predictor. Lifetime trauma showed no such association. TIV was also related to psychological distress and ethnicity, as well as sex but to a less consistent degree. In the Trauma Study, TIV predicted negative posttraumatic cognitions about others even when controlling for the experience of trauma and PTSD; however, contrary to hypotheses, it was unrelated to self-blame or self-worth. TIV was also associated with holding a wider concept of trauma (that is, rating a greater number of possible events as being “trauma”), although there was no such effect when people rated an event from their own lives. With respect to the Daily Stress Study, TIV had a negligible relationship with interpersonal stress; specifically, it had a weak correlation with the occurrence of daily interpersonal stress and no relationship to whether one’s worst event of the day was interpersonal in nature. It was, however, positively associated with participants’ predictions and recall of the amount of interpersonal stressors they would/did experience. It was also related to rumination following interpersonal stressors, which was subsequently related to the level of victimhood-relevant details included in a written reflection about an interpersonal stressor at follow-up. Overall, findings were somewhat mixed with respect to hypotheses. TIV does not appear redundant with the experience of victimization itself (historical and/or at the level of more minor daily hassles). Rather, to some extent, it may relate to these experiences by influencing how one anticipates, reflects on, and forms beliefs about them.
Faculty perspectives of undergraduate student academic writing underpreparedness
(2026) Toman, Rebecca; Lovell-Johnston, Meridith; Kaefer, Tanya; Clausen, Jessica; Bradford, Brent
Underpreparedness among first-year university students, particularly in academic writing and academic engagement, creates challenges for students and instructors and raises questions about how students are supported when underprepared for university. This qualitative research examined first-year English instructors’ perspectives to answer two questions: How first-year post-secondary students meet or do not meet the academic writing and adult learning expectations of first-year English instructors; and what do educators expect from university academic supports intended to address student underpreparedness in English university classes? Semi-structured interviews were conducted with 10 instructors from one Ontario university English department and data was analyzed using a combined theoretical model of Lea and Street’s Academic Literacies Model and Knowles’ Adult Learner Theory. The findings identified that the participants found argumentation quality, critical thinking and analysis presence, and clear and organized writing with evidence integration as key factors of exceptional academic writing, with student engagement and motivation as important characteristics of preparedness. However, instructors described gaps between these expectations and the abilities demonstrated by many first-year students, requiring support that is often misaligned, under-supported, and in need of better institutional communication. Concluding suggestions include institutional improvements and the potential of bridging Ontario grade 12 education with introductory university instruction. This would be a coordinated program encouraging student engagement, addressing topics including university expectations, high school to university transition, academic writing, and academic integrity.
Preparation, radiolabeling, and conjugation of an Aurora Kinase B Inhibitor to 198Au-activated nanoparticles for cancer imaging and therapy
(2026) Lorentson, Jessica; Campbell, Michael; Hou, Jinqiang; Gottardo, Christine
When targeting cancer, it is often necessary to attack the disease on multiple fronts. This work proposes the development of multifunctional nanoparticles (NPs) to deliver both a therapeutic radiation dose and a cancer-targeting (Aurora Kinase Inhibitor) chemotherapeutic directly to the tumour. Additionally, the incorporation of a diagnostic agent to the NP allows for a theranostic approach. The progression of the therapeutic agent can be subsequently monitored via the NPs as delivery vehicles, with the diagnostic agent allowing assessment of tumour dosage. The presence of leaky vasculature in many tumours facilitates the infiltration and accumulation of NPs in these tissues. The preparation of polyethylene-glycol (PEG)-stabilized gold NPs (AuNPs) has been achieved and enables the targeted delivery of both therapeutic and diagnostic agents directly to the tumour. In a CCK-8 cytotoxicity assay, the AuNPs were found to have an IC50 of 0.06  0.04 (n=10) mg/mL on the SiHa cell line, 0.08  0.07 (n=4) mg/mL on the CaSki cell line, and 0.041  0.002 (n=2) mg/mL on the C33A cell line. The subsequent use of cyclotron-based neutron activation to convert the AuNP into gold-198 NP (198AuNP) can be used to provide a therapeutic radiation dose. This conversion of gold into 198Au has been demonstrated and can facilitate the delivery of beta radiation directly to the tumour. The IC₅₀ of the ¹⁹⁸AuNPs decreased with increasing radioactivity, indicating an increase in cytotoxicity. At lower activity levels (111 and 278 Bq/mL), only a minor increase in toxicity was observed; however, further increases in activity (1,145 and 2,290 Bq/mL) resulted in a continued decrease in IC50, indicating enhanced cytotoxicity. The AuNP has been labelled with an aurora kinase inhibitor (AKI) as a chemotherapeutic and a cancer-targeting moiety. The Aurora Kinase B inhibitor of interest was found to have an IC50 of (1.0  1.2) x 10-3 (n=3) mg/mL on the SiHa cell line, (6.3  1.8) x 10-5 (n=3) mg/mL on the CaSki cell line, and (3.5  2.4) x 10-3 (n=3) mg/mL on the C33A cell line. Conjugating this inhibitor enhances both specific cancer cell targeting in addition to the enhanced permeability and retention (EPR) effect that allows for the AuNPs to enter the tumour tissue, and the killing capacity of the 198AuNP. The PEG chain used for the peptide linkage that connects the inhibitor to the AuNP has been synthesized, as well as the AuNP-AKI conjugate. The IC50 for the AuNP-AKI conjugate was determined to be 0.0298  0.0008 (n=2) mg/mL with a 30:1 ratio of PEG:PEG-AKI on SiHa. This work uniquely employs the use of a medical cyclotron for the simultaneous preparation of [18F]-fluoride for PET labelling and the neutron activation of the prepared AuNPs via the 197Au(n,γ)198Au reaction. A model system for the PET-radiolabelling of the AuNPs has been investigated and a method has been proposed to achieve 18F-labelling.
Exploring climate emotions and coping strategies of Canadian youth in a climate-focused program
(2026) Tait, Maren; Field, Ellen; Galway, Lindsay
Climate change education holds particular significance amid today’s social and ecological realities. Youth specifically are feeling the pressure of our changing climate, manifesting in feelings of anxiety and hopelessness. A climate education which recognizes these complex emotions and provides opportunities for youth to cope with these emotions through action is key. This research explores the role of an interdisciplinary, hope-focused environmental education program in shaping the climate emotions and coping strategies of its students. In this mixed methods case study, grade ten and grade twelve students from Claremont Secondary School’s Institute for Global Solutions participated in surveys and a focus group to gain insights to the relationship between the programming and their climate emotions and coping. The study found that youth in the IGS program are experiencing a breadth of emotions in relation to climate change, and use a variety of coping strategies. It was also identified that programming such as IGS can provide students with a positive orientation to both personal and collective climate action. This demonstrates the importance of educational models which support and acknowledge the emotional dimensions of teaching climate change, and fostering student agency. This research holds implications for educational practice, curriculum development, program development, and student well-being.
Moment stability of strongly nonlinear structural systems under random excitations
(2026) Ghaedi, Maral; Deng, Jian; Wiebe, Richard; Siddiqui, Sultan; Gong, Yanglin
Many structures in civil engineering are subjected to dynamic loadings. Examples include wind-induced vibrations of cables and tall buildings, wave loading on offshore structures, and seismic excitations acting on civil infrastructure. These dynamic excitations can often be described satisfactorily in probabilistic terms. Current research trends in structural dynamics are evolving from deterministic to stochastic analysis, from linear to nonlinear systems, from elastic to viscoelastic behavior, and from external excitation alone to incorporating parametric excitation. This thesis investigates the stochastic stability of strongly nonlinear structural systems subjected to random parametric excitations, with stochastic stability referring to the long-term probabilistic growth or decay of the system response. The principal stability measure employed in this study is the Moment Lyapunov Exponent (MLE), which characterizes the exponential growth or decay rate of the statistical moments of the system response. Knowledge of the MLE gives the almost-sure asymptotic stability of a stochastic dynamical system through the corresponding Lyapunov exponent. The MLE is the ideal avenue and the ultimate characteristic number for the study of the dynamic stability of stochastic dynamical systems. A unified analytical and numerical methodology is developed for the evaluation of MLEs of nonlinear oscillatory systems. The analysis is primarily based on the stochastic averaging method, which allows the original nonlinear stochastic differential equations to be reduced to averaged equations governing the slow evolution of key response variables. Particular emphasis is placed on transformations based on the system Hamiltonian or total mechanical energy, through which the response of strongly nonlinear oscillators can be represented by an energy envelope. This formulation enables the derivation of analytical expressions for the drift and diffusion coefficients governing the stochastic evolution of the system energy and provides a tractable framework for moment stability analysis. In addition to the analytical formulation, a modified Monte Carlo simulation framework is developed for the numerical estimation of MLEs. In contrast with conventional algorithms that rely on the Euclidean norm of the state vector, the proposed approach employs the square root of the system energy as the generalized amplitude used in periodic normalization procedures. This energy-based formulation offers improved numerical robustness and provides a physically meaningful measure for the response of strongly nonlinear systems, allowing reliable estimation of the MLE through long-term stochastic simulations. Using the developed framework, the stochastic stability characteristics of nonlinear systems are investigated under three representative classes of stochastic excitation: Gaussian white noise, real noise modeled by the Ornstein–Uhlenbeck process, and bounded noise with phase modulation generated by a Wiener process. These excitation models represent different spectral and amplitude characteristics and physical realism commonly encountered in engineering applications. For each case, analytical expressions or approximate eigenvalue formulations for the MLE are derived, and the corresponding stability regions are evaluated. The analytical MLE predictions are compared against independent Monte Carlo estimates obtained directly from simulations of the original stochastic equations, demonstrating strong agreement between theoretical and numerical results. Furthermore, the thesis examines the influence of viscoelastic behavior, represented by a Maxwell-type model, on the stochastic stability of nonlinear systems. Viscoelastic effects introduce additional energy dissipation mechanisms and memory-dependent dynamics that may significantly alter the stability characteristics of the system. The results demonstrate that viscoelastic parameters, including relaxation amplitude and decay rate, can modify the effective damping properties of the system and thereby shift the moment stability boundaries under stochastic excitation. Overall, this thesis provides a comprehensive investigation of stochastic stability of strongly nonlinear structural systems and extends the MLE framework to include realistic stochastic excitation models and viscoelastic material behavior. The analytical formulations and numerical methodologies developed herein contribute to a deeper understanding of stochastic parametric instability in nonlinear structures and provide practical tools for assessing the probabilistic stability and reliability of engineering systems subjected to uncertain dynamic environments.