SACM - Canada
Permanent URI for this collectionhttps://drepo.sdl.edu.sa/handle/20.500.14154/9651
Browse
1258 results
Search Results
Item Restricted The Glucocorticoid Receptor Regulates Myonuclear Positioning During Skeletal Muscle Differentiation(Saudi Digital Library, 2025) Alharbi, Shaden; Wiper-Bergeron, NadineProper myonuclear positioning is essential for skeletal muscle function and relies on the coordination of the nucleoskeleton, cytoskeleton, and the Linker of Nucleoskeleton and Cytoskeleton (LINC) complex. Although glucocorticoids are widely used therapeutically to treat muscular dystrophies, the muscle-intrinsic mechanisms underlying their effects on improving muscle strength remain unclear. Here, we investigate the role of the glucocorticoid receptor in regulating myonuclear positioning during myogenic differentiation and skeletal muscle regeneration. Pharmacological inhibition of the glucocorticoid receptor (GR) with RU-486 in C2C12 myotubes or knockdown of GR expression in vivo resulted in disrupted nuclear alignment. Mechanistically, GR inhibition decreased the levels of Lamin A and SUN1 proteins within the soluble fraction. This, in turn, disrupted the alignment of pericentrin and the Golgi apparatus to the nuclear envelope, ultimately disorganizing the microtubule network. Together, these data identify GR as a critical regulator of myonuclear positioning and of nuclear-cytoskeletal integrity during muscle differentiation, providing mechanistic insight into how glucocorticoid therapies may improve muscle function in patients with muscular dystrophies.8 0Item Restricted Data-Efficient Deep Learning for Predictive Modelling of Conventional Single Slope Solar Stills: Leveraging Transfer Learning and Tailored Data Augmentation Strategies(Saudi Digital Library, 2025) Migaybil, Hashim; Gopaluni, BhushanConventional single-slope solar stills are essential for decentralized freshwater production, yet their performance optimization is limited by small datasets and the nonlinear dynamics of desalination. This doctoral thesis addresses these constraints by developing and evaluating data-efficient supervised machine learning frameworks to predict freshwater productivity (Pstd, L/m²·day). The study integrates a novel high-performance solar still design with two complementary learning paradigms: Transfer Learning (TL) and tailored Data Augmentation (DA). The research begins with the design and MATLAB/SIMULINK simulation of a photovoltaic-assisted single-slope solar still engineered for improved thermal performance. The hybrid system achieved a peak efficiency of 45%, and its 730-sample dataset served as the “source” domain for TL. The first paradigm introduces a cross-design TL framework. A source Artificial Neural Network (ANN) was pre-trained on the hybrid system simulation data, and its learned weights were transferred and fine-tuned to model a conventional solar still using only 365 experimental samples. The optimized TL-based ANN (5-64-64-1) outperformed both randomly initialized ANNs and Multiple Linear Regression (MLR), achieving an Overall Index of Model Performance (OIMP) of 0.872 and demonstrating superior predictive accuracy and generalization. The second paradigm develops a tailored DA strategy to directly expand the conventional still’s limited dataset. Gaussian noise–based jittering was applied to sequential inputs within a 7-day look-back window to generate synthetic training data for a one-dimensional Convolutional Neural Network (CNN-1D). The optimized CNN-1D model—comprising three 128-filter convolutional layers—substantially outperformed baseline CNN and Support Vector Regression (SVR) models, achieving an RMSE of 0.045 and an OIMP of approximately 0.97. A threshold-based classification method was also introduced to translate raw predictions into interpretable productivity categories. Overall, this thesis provides a comparative evaluation of TL and DA approaches, validating their effectiveness in addressing data scarcity in solar still modeling. Key contributions include a novel cross-design TL framework, a specialized DA technique for time-series solar still data, and highly accurate predictive models. The findings provide practical, cost-effective tools for optimizing conventional solar stills and underscore the broader potential of advanced machine learning in renewable energy–driven desalination.19 0Item Restricted Simulation in Perinatal Training in Family Medicine Postgraduate Education: A Mixed Studies Literature Review(McGill University, 2025) Samman, Ahdabdulkareem; Charo, RodriguezIntroduction: Family physicians are important providers of perinatal care, but decreased exposure to obstetric training during residency and shifting program priorities have prompted concerns about their preparedness. Simulation-based medical education (SBME), which is widely used in other medical professions, presents a promising approach to addressing training gaps by improving clinical competence, confidence, and communication skills in addressing obstetric situations. Despite its potential, SBME is insufficiently utilized in family medicine postgraduate education due to inadequate resources and faculty training. This literature review synthesizes existing research on SBME interventions in perinatal care for family medicine residents, providing a thorough overview of current practices and informing strategies to improve and strengthen maternal training in this field. Methodology and Methods: A mixed studies literature review was conducted. The search encompassed the biggest medical scientific literature database, i.e., Ovid MEDLINE (1946- December 2024). The Mixed Methods Appraisal Tool (MMAT) was used to assess the methodological quality of records retained. The data extracted from the selected studies were analyzed employing a data-based convergent mixed methods design, enabling the integration of qualitative and quantitative findings. Result: A total of 24 studies met the criteria for data extraction. Rigorous line-by-line coding was applied to both Result and Discussion sections of included articles. Findings were systematically categorized into four overarching themes, including: “Variety of simulation educational interventions in Family Medicine postgraduate training in perinatal care”, “Family Medicine Residents’ Perceptions and Attitudes regarding Simulation in Perinatal Training”, “Knowledge and Skills Outcomes Gained through Simulation in Perinatal Care”, and “Limitations and Gaps in Simulation-Based Perinatal Training”. Discussion: This review highlights the breadth and effectiveness of simulation-based education in enhancing Family Medicine residents' attitudes, knowledge, and procedural skills, in delivering perinatal care. While evidence supports improvements in technical competencies and self-efficacy, the findings also reveal a few limitations in non-technical skill development, knowledge retention, and equitable access. These insights underscore the need for better curricular integration, faculty training, and future research to optimize simulation design and expand its accessibility and impact across diverse Family Medicine training programs.11 0Item Restricted Supervision and autonomy in Periodontics Surgical Education: a Grounded Theory Study at an Academic Institution.(Saudi Digital Library, 2025) Alomar, Nuha; von Bergmann, HsingChiAbstract Background Clinical supervision is crucial in postgraduate surgical education, where balancing resident autonomy with patient safety is essential. While the development of autonomy is widely discussed in medical education, there is limited understanding of how supervision shapes this process in periodontic surgical education. Objective This dissertation aims to explore the processes of supervision and autonomy development in periodontics surgical education by generating substantive theories that explain how supervision is performed and how resident autonomy evolves over time. Methods A grounded theory method, following the approach of Strauss and Corbin, was used to develop substantive theories based on empirical data. Data collection included semi-structured interviews with eight instructors and seven residents across different program stages in an academic institution. Theoretical sampling guided participant selection, allowing refinement of emerging categories to be developed and refined through constant comparison. Memos and diagrams were used to track concept development, explore relationships between categories, and ensure coherence in the construction of theory. To ensure credibility, member checking was conducted in conjunction with data triangulation, incorporating multiple stakeholders’ perspectives. Saturation was reached when no new concepts emerged, confirming the robustness of the developed frameworks. Findings Two substantive theories emerged from this study. Adaptive Reasoning Mentorship explains the instructors' decision-making processes during supervision as responsive adjustments made in real-time. It illustrates how they adapt their approach based on their assessment of residents’ needs, patient considerations, and situational demands, reflecting on their experiences and expectations. Conditioned Relational Autonomy reconceptualizes autonomy as a relational, context-dependent construct that facilitates learning, rather than an individual achievement. This theory posits that autonomy develops through ongoing interactions between residents and instructors and is shaped by contextual influences. In this context, autonomy is negotiated through trust, prior experiences, residents’ demonstrated accountability, and instructors' interpretations of their educational and clinical responsibilities. Conclusion The findings expose the complexity of supervision in periodontics surgical education and emphasize that autonomy is not a fixed state but rather a negotiated and context-dependent progression. These insights contribute to the broader discourse on medical education and offer practical implications for improving supervisory approaches in surgical education.4 0Item Restricted Understanding Parental Caregiving for Children with Cerebral Palsy in Saudi Arabia: A Multi-Method Study Combining Insights from a Scoping Review and Qualitative Data(Saudi Digital Library, 2025) Alqahtani, Ashwaq Amer; Afolasade, FakoladeCerebral palsy (CP) is the most common motor disability in childhood, affecting approximately 2-3 per 1,000 live births worldwide. The lifelong nature of CP places significant caregiving responsibilities on families, particularly parents. Understanding parents' experiences and support needs is critical to informing effective interventions and advancing disability research. While CP caregiving has been widely studied, research involving Arab parents of children with CP, particularly in Saudi Arabia, remains scarce. The overarching goal of this thesis was to explore the caregiving experiences of Saudi parents of children with CP and characterize their support needs through a social-ecological lens. This thesis includes two studies, starting with a scoping review that examined existing research on CP caregiving in the Arab contexts, identified gaps in knowledge, and offered recommendations for future studies. Then, a qualitative exploratory descriptive interview study involving 12 Saudi parents from Qassim, Saudi Arabia, aimed to explore their caregiving experiences and characterize their support needs. The scoping review revealed that mothers are predominantly the primary caregivers in Arab contexts, and that caregiver burden is a major concern. However, the qualitative study in Saudi Arabia showed that caregiving responsibilities are shared between both parents, with roles shaped by traditional gender norms. Parents faced significant emotional, physical, material, and informational challenges, with financial strain being particularly pronounced. Barriers to accessing education and health care services further contributed to caregiver stress. However, Islamic spiritual values played a pivotal role in fostering collectivism and community involvement, serving as vital sources of resilience and social support for parents navigating caregiving responsibilities. Overall, the integrated findings showed that effectively supporting Saudi and Arab parents of children with CP depends on understanding their unique experiences and cultural context. To achieve this understanding, families, communities, support organizations, and the government must work together. Future research and program development should consider these contexts to support and effectively address the needs of parents of children with CP in Saudi Arabia.13 0Item Restricted Diagnostic Evaluation of Patients with Epileptic Spasms in the era of next-Generation Sequencing(Saudi Digital Library, 2024-10-11) Alqahtani, Mohammed Azib M; Costain, GregoryObjective: Epileptic spasms (ES) can be caused by a variety of etiologies. However, in almost half of cases, the etiology is unidentified. With the advent of next-generation sequencing (NGS), the recognition of genetic etiologies has increased. Methods: We retrospectively reviewed the medical records of patients with ES who were evaluated in the comprehensive epilepsy program at King Fahad Specialist Hospital Dammam between 2009 and 2022. Results: Our data show that in 57.7% of patients with ES, the etiology was unidentified after a standard clinical evaluation and neuroimaging. Of these patients, n = 25 (35.2%) received a genetic diagnosis after some form of genetic testing, and 3.1% of patients from specialized metabolic work indicated the need for genetic testing to confirm the diagnosis. Karyotyping led to a diagnosis in 3.6% of patients, and chromosomal microarray led to a diagnosis in 7.1%. An NGS epilepsy gene panel (EP) was done for 45 patients, leading to a diagnosis in 24.4% (n = 11). Exome sequencing was done for 27 patients, including n = 14 with non-diagnostic panel testing; it led to a diagnosis in 37.3% (n = 10). Exome sequencing led to a diagnosis in 61.5% of patients without a previous panel test and in only two patients who had previously had a negative panel testing. Significance: In this article, we present the diagnostic evaluations of ES for a cohort of 123 patients and discuss the yield and priority of NGS for evaluating ES. Our findings suggest that exome sequencing has a higher diagnostic yield for determining the etiology of ES in patients for whom the etiology is still unclear after an appropriate clinical assessment and a brain MRI.3 0Item Restricted Three Essays in Mental Health Economics: Education and Labor Market Outcomes(Saudi Digital Library, 2025-06) Alarabim, Hosam; Koreshkova, TatyanaThis dissertation explores how mental and physical health influence key economic outcomes over the life course, focusing on education, occupational outcomes, and workplace productivity. Using longitudinal data from the National Longitudinal Study of Adolescent to Adult Health (Add Health), the study employs advanced modeling techniques, including Generalized Structural Equation Modeling (GSEM) and mixed-effects regression, to construct latent health measures and quantify their economic consequences. The first chapter examines the impact of adolescent mental health on academic achievement, particularly high school completion and college enrollment. It addresses the limitations of using narrow diagnostic proxies for mental health by applying a factor-analytic approach to create latent constructs. The findings reveal that better mental health significantly improves educational attainment, with a stronger effect on college entry than on high school completion. The second chapter investigates how health status shapes occupational sorting across two major classifications: white-collar and full-time employment. It finds that individuals with poor mental health are disproportionately concentrated in low skill, physically demanding, blue-collar jobs, while those with better health are more likely to enter cognitively intensive, white-collar occupations. Physical health also influences job type, reinforcing disparities in labor market access and long-term mobility. The third chapter evaluates the effect of mental health on workplace productivity. By constructing a composite latent productivity score, based on job satisfaction, hours worked, and income, the study estimates the long-term effects of lagged health status. A one standard deviation increase in mental health is associated with a 0.0251 rise in latent productivity and a 0.0201 increase in wage measure of productivity, confirming the strong and persistent influence of psychological well-being. Together, these chapters show that mental health is a critical determinant of economic opportunity, shaping individual outcomes from adolescence through adulthood.16 0Item Restricted The effect of corticosteroids on sinus microbiota in chronic rhinosinusitis patients with nasal polyposis(McGill University, 2019) Alammar, Yousif; Rousseau, Simon; Tewfik, Marc; Rousseau, Simon; Tewfik, MarcBackground: Chronic rhinosinusitis with nasal polyposis (CRSwNP) is a multifactorial disease with no known single cause, but it is thought that bacteria play a role in the disease process. The short-term response of bacterial communities to corticosteroid therapy has been found to be unpredictable. As a result, this pilot study aims to assess the long-term effect of corticosteroid therapy on sinus microbiota in chronic rhinosinusitis patients with nasal polyposis (CRSwNP). Methods: A longitudinal prospective case-control study was done on patients with CRSwNP and on healthy subjects. Patients with CRSwNP were randomly allocated to a maximal medical therapy (corticosteroids and antibiotics) treatment group or a corticosteroid-only treatment group. Data was collected at 3 time points (before treatment, 1 and 3 months after treatment): A guarded sinus swab was collected from the middle meatus; the SNOT-22 questionnaire was used to assess clinical symptoms. Specimens were cultured and Matrix-assisted laser desorption ionization–time of flight (MALDI-TOF) mass spectrometry (MS) was used as a bacterial detection method. The raw data produced was analyzed to characterize the sample and to assess the response to each medical treatment. Results: Data from 29 patients with CRSwNP (16 maximal medical therapy; 13 corticosteroids only) was compared to 15 healthy subjects. Patients reported significant symptoms improvement initially (1- month), but not on the long-term (3-months). This result was found as a response to both treatment groups, whether or not antibiotics was used. There was no significant difference in the sinus microbiota prevalence between CRSwNP patients and normal subjects. After three months from treatment, Corynebacterium genera tended to increase in the maximal medical therapy group, while Staphylococcus and gram-negative genera (Pseudomonas) tended to increase after corticosteroid treatment. Smoking, aspirin sensitivity and previous endoscopic sinus surgery were found to be co-factors significantly associated with the response to systemic corticosteroid therapy. Conclusion: In this pilot study both treatment options were effective on the short-term, but not on the long-term with no clear sinus microbiota response linked. As a result, this study agrees with previous reports that discourage the use of systemic antibiotics without evidence of active infection.23 0Item Restricted Exploring Physiologic Markers for the Identification of Vasovagal Syncope(University of Calgary, 2024) Robert S Sheldon, Mohammed Alsaleh; Sheldon, Robert SBackground: Vasovagal Syncope (VVS) is a common cardiovascular disorder, with at least 40% of individuals experiencing at least one episode in their life and about 20% of adults experiencing recurrent episodes. Traditional diagnostic methods such as the Head-Up Tilt (HUT) test and Implantable Cardiac Monitors (ICM) have significant limitations, including limited availability, high costs, and intensive resource requirements. A novel wearable, beat-to-beat blood pressure (BP) monitor is being developed to address these issues. This device, worn on the ear, samples BP at 50 Hz, stores and streams data, and features a rechargeable battery lasting up to 30 hours. This innovative solution will offer a cost-effective, user-friendly alternative for VVS management, potentially improving diagnostic accuracy and patient outcomes. Aims: We aimed to investigate the potential of a wearable beat-to-beat BP monitor in diagnosing vasovagal syncope. The thesis is structured around the following objectives: Objective 1: Provide a detailed narrative review of vasovagal syncope physiology, the BezoldJarisch reflex, and the need for a wearable beat-to-beat BP monitor. Objective 2: Validate the short-term blood pressure fluctuations during scripted physiological changes with a wearable beat-to-beat BP monitor. Methods: The narrative review explores physiological mechanisms underlying VVS, highlighting serotonin's role. For Objective 2 data were collected from 14 participants during activities such as rhythmic breathing and hand grips to validate the ear BP monitor. Spectral and coherence analyses assessed synchronization between the ear monitor and the Modelflow system, with non-parametric methods evaluating statistical differences. ii Results: The narrative review identified key markers for monitoring VVS. The narrative review identified key markers for monitoring vasovagal syncope (VVS), which guided the validation of the ear BP monitor. Data was successfully collected from 14 out of 20 participants, comprising 47% male and 53% female subjects, with an average age of 24.29 ± 5.61 years. The device demonstrated high coherence values (>0.95) across all activities, indicating strong synchronization with the Modelflow system. No significant differences were observed in systolic BP measurements, with p-values of 0.37 for low-frequency components and 0.18 for high-frequency components, confirming the ear BP monitor's ability to capture BP fluctuations during dynamic physiological changes accurately. Further analysis identified the fundamental heartbeat frequency as 1.4 Hz, with harmonics at 2.8 Hz, 4.2 Hz, and beyond. The coherence of these harmonics highlighted the consistency of the heartbeat-induced waveform shapes, indicating that the arterial blood pressure measurements from the Modelflow and EarBP devices were stable and reliable. Coherence across frequencies revealed comparable signal synchronization between the two devices, with significant coherence observed at the fundamental frequency and its harmonics. Coherence values were tightly clustered near the median across all conditions, with the Valsalva maneuver showing slightly more significant variability due to lower coherence values in some participants. These results collectively validate the ear BP monitor as a reliable tool for arterial pressure measurement and synchronized waveform analysis. Conclusion: This thesis advances the understanding of vasovagal syncope (VVS) physiology and validates using a novel ear-based blood pressure monitor. The narrative review identified key physiological markers and mechanisms, including the Bezold-Jarisch reflex and serotonin signaling, central to VVS episodes. The validation study demonstrated high accuracy and synchronization of the ear BP monitor with established standards, offering a non-invasive, iii wearable alternative for real-time blood pressure monitoring. While promising, further research is required to expand its validation across diverse populations and address potential limitations such as motion artifacts. These findings support the use of an ear BP monitor as an innovative tool with the potential to diagnose vasovagal syncope2 0Item Restricted THE NEUROPHYSIOLGY OF SELECTIVE ATTENTION IN HUMAN SUBCORTICAL MOTOR NUCLEI(University of Toronto, 2025) Alanazi, Frhan; William, HutchisonSelective attention and working memory are fundamental cognitive processes traditionally attributed to cortical regions. Emerging evidence suggests that subcortical motor nuclei, such as the thalamus and basal ganglia, also play crucial roles in these functions, but the mechanism is still unclear. This thesis aimed to examine the neurophysiological mechanisms of selective attention and working memory in subcortical motor nuclei through intraoperative single-unit and local field potential (LFP) recordings in humans. In the first study, neuronal activity was recorded from the ventral intermediate nucleus (Vim) and ventral oral anterior/posterior nuclei of the motor thalamus in 25 patients with parkinsonian and non-parkinsonian tremors during an auditory oddball task. Results showed a significant decrease in neuronal firing rates and in beta-band (13–35 Hz) oscillations to the deviant tones, indicating the involvement of Vim in auditory selective attention. Parkinson’s disease (PD) patients off medication exhibited increased beta power but reduced modulation to attended tones, suggesting dopamine's role in modulating thalamic beta oscillations for selective attention. The second study focused on the centromedian nucleus (CM) of the thalamus in 11 epilepsy patients performing a similar auditory attention task. CM neurons demonstrated selective, multiphasic firing and beta/low gamma (13–45 Hz) modulations to deviant tones in 81% of neurons tested. These findings highlight the CM's participation in cognitive function, supporting its role under top-down control and implicating beta and gamma oscillatory activities in cognitive processing. The third study investigated neuronal activity in the subthalamic nucleus (STN) and Vim during a visual 1-back task in 16 patients with PD or essential tremor. Both nuclei exhibited selective firing rate changes and beta desynchronization in response to target stimuli. Vim beta desynchronization occurred earlier than in the STN, even preceding the stimulus, suggesting a role in stimulus prediction. Collectively, these studies provide evidence that subcortical motor nuclei are actively involved in selective attention and working memory and have significant implications for understanding the neural circuitry underlying cognitive functions and the pathophysiology of neurological disorders like Parkinson’s disease and epilepsy. Furthermore, they offer potential insights for developing deep brain stimulation therapies targeting cognitive symptoms associated with these conditions.19 0