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Recent Submissions
INVESTIGATION OF THE NOVEL INTERACTION BETWEEN THE HUMAN RECEPTOR FOR ACTIVATED C KINASE 1 (RACK1) AND 26S PROTEASOME
(2025-03-21) Shi, Yunnuo; Not Applicable; Doctor of Philosophy; Department of Microbiology & Immunology; Not Applicable; Stanley Moore; Not Applicable; Jeanettee Boudreau; David Langelaan; Craig McCormick; Zhenyu Cheng
The 26S proteasome is a highly conserved protein degradation complex. It facilitates ATP- and ubiquitin-dependent protein degradation and plays a central role in the ubiquitin-proteasome system (UPS). The proper function of the proteasome is essential for maintaining protein homeostasis by removing damaged and misfolded proteins as well as regulating protein turnover under various physiological and pathological conditions. RACK1, a highly conserved WD40 repeats scaffolding protein, is known for its ability to coordinate diverse protein-protein interactions. RACK1 is involved in the protein homeostasis network by serving as a platform for recruiting protein substrate or co-factors, as well as organizing protein complexes formation. Interestingly, RACK1’s involvement in the regulation of proteasome function has not been thoroughly explored.
This study identified a novel interaction between RACK1 and the proteasome, shedding light on RACK1’s potential role in regulating proteasome activity. RACK1 was found to directly interact with 26S proteasome preferentially with 19S regulatory proteasome subcomplex through the N-terminal three WD repeat. RACK1 selectively enhances the proteasome’s trypsin-like activity in a purified protein system without affecting other catalytic activities. In the cellular context, RACK1 was shown to play a role in maintaining basal proteasome gene expression independently of NRF1 and NRF2 activation, the master transcription factors regulating proteasome genes. Furthermore, RACK1 was found to mitigate stress-induced NRF2 and proteasome gene expression, potentially through its role in maintaining proteasome activity and mitigating oxidative stress. These findings provide valuable insights into the regulatory interplay between RACK1 and the proteasome.
In summary, this study establishes RACK1 as a novel and multifaceted regulator of proteasome activity, participating in both direct modulation and transcriptional regulation of proteasome function. These findings expand our understanding of the mechanisms governing proteasome function and highlight the potential of RACK1 as a therapeutic target in diseases associated with proteasome dysfunction and impaired protein homeostasis.
The impact of the Canadian emergency response benefit during the COVID-19 pandemic on the prevalence of household food insecurity in Canada
(2025-03-12) Jimenez, Laura; Not Applicable; Master of Science; Department of Community Health & Epidemiology; Not Applicable; n/a; Not Applicable; Sanja Stanojevic; Leah Cahill; Daniel Dutton
Background: During the COVID-19 pandemic, the Canada Emergency Response Benefit (CERB) was introduced to mitigate the impact of sudden mass unemployment. To date, no study has examined the association of CERB and the prevalence of food insecurity (FI).
Objectives: To determine if the introduction of CERB reduced the prevalence of FI in Canada using a difference-in-differences (DID) analysis of Canadian Income Survey (CIS) data, and subgroups of interest: female-led lone parent households and households living in poverty.
Methods: CIS cycles 2018-2020 linked to CERB (weighted n=27,535,068) were used. A DID analysis estimated the association between CERB receipt and the log odds of FI.
Results: Levels of FI were maintained in CERB-recipient households and decreased in non-CERB recipients. CERB receipt modified the relationship with FI between CERB and non-CERB households (0.145, p= 0.034). Conclusion: This study shows that despite mass unemployment, no increases occurred in FI among unemployed CERB recipient households.
PIDNET-SLAM: A MULTI-RESOLUTION SEMANTIC SLAM ALGORITHM FOR DYNAMIC SCENES
(2025-03-16) Rajan, Siddharth; Yes; Master of Applied Science; Department of Electrical & Computer Engineering; Not Applicable; n/a; Not Applicable; Dr. Mae Seto; Dr. Kamal El-Sankary; Dr. Jason Gu
Simultaneous Localization and Mapping (SLAM) enables robots to map their surroundings while determining their positions in real time. Traditional SLAM systems typically assume static environments, causing accuracy issues when dynamic objects are present. Existing methods, which often use deep learning techniques like semantic segmentation, instance segmentation, and object detection, increase accuracy but add significant computational overhead, making them unsuitable for real time use. Therefore, a robust and computationally efficient SLAM solution capable of effectively handling dynamic scenes is needed.
To address these challenges, we introduce PIDNet SLAM, an innovative extension of ORB SLAM 3 that effectively manages dynamic environments. PIDNet SLAM incorporates a multi resolution semantic segmentation network based on PIDNet, consisting of two parallel branches: a low resolution branch actively processing non keyframes, and a high resolution branch providing supplementary high resolution features without interfering with the main workflow. Additionally, a lightweight geometric module uses geometric transformations and optical flow to identify and eliminate dynamic features, enhancing the system’s overall accuracy.
Evaluations on the dynamic TUMM RGB-D dataset show PIDNet SLAM significantly outperforming existing methods like Dyna SLAM, SOLO SLAM, and ORB SLAM 3, achieving over 97% improvement in localization accuracy in dynamic scenarios. Remarkably, the system maintains an average processing time of only 49ms per frame on a low power GPU, demonstrating an optimal balance between accuracy and computational efficiency. PIDNet SLAM thus presents a critical advancement toward effective real time SLAM in dynamic environments, with potential future improvements focusing on refining the low resolution branch for even faster performance.
Mapping the Complex Patterns of Degradation in Commercial Lithium-Ion Batteries Using X-Ray Imaging and Diffraction
(2025-03-13) Bond, Toby; Not Applicable; Doctor of Philosophy; Department of Physics & Atmospheric Science; Not Applicable; Jay Whitacre; Yes; Theodore Monchesky; Michael Metzger; Jeff Dahn
Understanding and mitigating degradation in Li-ion batteries is a major area of focus in the electric vehicle industry. Studying battery degradation often requires long-term cycling experiments, which are best done with machine-made cells using commercial form factors to accurately represent real- world operating conditions.
In this thesis, we use synchrotron-based X-ray imaging and diffraction to comprehensively study the structural and functional changes that occur in commercial cells after thousands of cycles. This work explores multi-scale effects that have not previously been observed and fills the gap between nano-scale and macro-scale in-situ imaging that exists in the literature. Time-resolved, operando experiments capture the kinetic effects of degradation and reveal their complex, spatially heterogeneous nature. The use of commercial-form- factor cells in this work also provides new insights into how cell geometry, operating conditions, and even gravity can significantly influence the patterns of degradation that form after extended cycling.
Activity Adjustment in Response to Chronic Back Pain
(1994-09) Archibald, Elizabeth Jean; Not Applicable; Master of Arts; School of Health & Human Performance; Not Applicable; unknown; Not Applicable; Phil Compagna; Geraldine Hart; Cheryl Kozey; Rene Lyons
The purpose of this qualitative research study was to explore work and leisure adjustment in nurses with a chronic work-related back injury. A face-to-face individual interview was conducted with ten female nurses, aged 35-49 years, recruited from a pain clinic. The acquisition of a disability due to an occupational accident not only resulted in a loss of earnings, but also generated a complete set of adaptive tasks for the nurse and her family. The themes that emerged from content analysis of interviews with ten nurses included the need for constant adaptation in daily routines, the need for instrumental and emotional support, specific role adaptations, leisure participation, and involvement in the Workers' Compensation system. Work and leisure adjustment was an added adaptive task that determined an individual's adjustment outcome. Future research and services should attend to adjustment styles in work and leisure.
Coping Strategies, Burnout, and Intent to Leave Among Critical Care Nurses
(1991-09) Lauzon, Laurie Marie; Not Applicable; Master of Nursing; School of Nursing; Not Applicable; unknown; Not Applicable; Brian Eastwood; Florence Myrick; Judith Ritchie
There has been a great deal of research interest devoted to the stressful situations encountered in critical care nursing, but few attempts to explore the relationships between individual responses to stressful situations and outcome variables. Guided by the framework of stress and coping proposed by Lazarus and Folkman (1984), this study examined the relationship between the coping behaviours critical care nurses used to manage a hypothetical stressful situation and outcomes, including burnout and intent to leave.
Self-report data were collected from 173 critical care nurses from three agencies in Atlantic Canada. Instruments used to measure the study variables included: the Ways of Coping Questionnaire (Lazarus & Folkman, 1984), the Maslach Burnout
Inventory (Maslach & Jackson, 1986), and a single item measure of intent to leave. A variety of descriptive and inferential statistics were used to explore the relationships between the study variables.
The most frequently used coping strategies were planful problem-solving, self-controlling, and seeking social support. Only one of the eight methods of coping measured, planful problem-solving, was significantly related to tenure in critical care nursing. The findings demonstrated a significant relationship between the nurses choice of coping strategies and burnout. Escape/avoidance and confrontive coping were predictive of burnout. Planful problem-solving and positive reappraisal were negatively related to burnout. Burnout was also predictive of the nurses' intent to leave their current positions. The findings suggest that both personal and situational factors, as well as individual responses to stressful situations have an impact on the turnover of nursing staff in critical care units.