SACM - United States of America
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Item Restricted PERSON-CENTERED KIDNEY CARE AND TRANSITION TO DIALYSIS: AN INVESTIGATION FROM SAUDI ARABIA(Saudi Digital Library, 2027-01-01) Alfahad, Abdulrahman Abdulmuslih S; Toles, Mark P; Almutary, Hayfa; Crandell, Jami; Ya-Ke “Grace” Wu; LeBlanc, MathewThis dissertation examines Person-Centered Care (PCC) in patients with Advanced chronic kidney disease (CKD) on dialysis in Saudi Arabia. It aims to advance PCC research and inform practical applications through five main objectives: (a) characterize Patient-Reported Outcomes (PROs) in CKD; (b) describe patient engagement among adult non-dialysis CKD patients; (c) identify population characteristics, including emotional and informational support, associated with patient engagement; (d) examine the relationship between patient engagement and health-related outcomes; and (e) characterize patient experiences during the transition to dialysis and identify factors that facilitate unplanned dialysis initiation. Chapter 2 findings of a scoping review of studies conducted in Saudi Arabia, which identified literature gaps, particularly in the standardized measurement of PROs, non-individual or environmental factors relate to patient-reported outcomes, and the underrepresentation of non-dialysis CKD patients in research. Chapter 3 reports the findings of a cross-sectional study of 128 patients which found that most participants scored the lowest engagement level. Key predictors of low engagement were low education level, low emotional and informational support. Chapter 4 reports findings from a qualitative study exploring the reasons that patients often initiate dialysis under emergency or unplanned circumstances. Through in-depth interviews with 18 patients who experienced unplanned dialysis initiation, findings characterize a range of individual, social, and healthcare system factors that contributed to unplanned dialysis initiation. The findings from this dissertation identifies actionable strategies to enhance person-centered and value-based care. The studies collectively highlight the urgent need for improved pre-dialysis care, including earlier nephrology care, integration of multidisciplinary teams, and proactive engagement of patients. Future research should prioritize designing and evaluating structured pre-dialysis programs that promote timely planning and smooth transitions to dialysis, incorporating elements such as patient education, self-management support, and activation strategies. At the policy and practice level, embedding routine PRO measurement, strengthening patient-provider communication, and tailoring care to patients’ social and emotional needs are essential to optimizing CKD care and aligning it with Saudi Arabia’s Vision 2030 healthcare transformation.7 0Item Restricted Temporal Splitting Schemes for Multiscale Problems(Saudi Digital Library, 2027-08-09) Alshahrani, Mohsen Ghanem Abdullah; Efendiev, YalchinMany real-life problems have a multiscale nature and high contrast coefficients. High contrast is known to pose significant challenges in numerical simulation, especially for time-dependent problems. Implicit methods are commonly used for time discretization; although they are unconditionally stable, they require expensive computations at each time step. In contrast, explicit methods are computationally efficient per time step but require very small time steps to maintain stability, due to the mesh size and contrast. We propose temporal splitting algorithms for multiscale problems in mixed form that balance the efficiency of explicit methods with the stability of implicit methods. This approach is applied to flow, wave, and quasi-gas-dynamic (QGD) problems. We decompose the pressure space into two components: a coarse-grid part and a correction part. Each is paired with a corresponding velocity space, namely a coarse-grid velocity space and a correction velocity space. The coarse-grid subspaces are designed to capture fast-scale features influenced by high-contrast variations, while the correction subspaces account for slow-scale features that are independent of contrast and not resolved by the coarse-grid approximation. Using this decomposition, we develop temporal splitting schemes that treat fast components implicitly and slow components explicitly. The stability of the proposed algorithms is ensured through a careful design of multiscale spaces. We also show that time stepping in the correction spaces is independent of contrast. Additionally, we find that the allowable time step scales with the coarse mesh size, which can lead to significant computational savings. We further propose multicontinuum splitting schemes for the wave equation and the quasi-gas-dynamic problem with high-contrast coefficients. To separate fast and slow dynamics in the system, we decompose the solution space into two components. This is achieved by introducing physically meaningful macroscopic variables and employing the expansion in multicontinuum homogenization. Based on this decomposition, we formulate partially explicit time discretization schemes in which the fast (contrast-dependent) component is treated implicitly to ensure stability, while the slow (contrast-independent) component is treated explicitly to enhance computational efficiency. We introduce the concept of discrete energy and derive corresponding stability conditions, which remain independent of contrast when the continua are properly chosen. In addition, we discuss strategies for optimizing the space decomposition. Numerical examples are presented to validate the accuracy and stability of the proposed schemes.51 0Item Open Access UNDERSTANDING REPEAT USE AND WORD-OF-MOUTH IN RESTAURANT RESERVATION APPS: AN INTEGRATED UTAUT2 AND USES & GRATIFICATIONS APPROACH(Saudi Digital Library, 2025-07-16) Alhaidar, Maher; Joung, DavidThis study explores the technological and psychological factors influencing users’ repeat use and word-of-mouth (WOM) behavior regarding restaurant reservation apps in Saudi Arabia. By integrating the Unified Theory of Acceptance and Use of Technology 2 (UTAUT2) with the Uses and Gratifications (U&G) Theory, the research develops a comprehensive framework to assess how constructs such as performance expectancy, effort expectancy, hedonic motivation, price-saving orientation, societal pressure, and various gratification types shape e-satisfaction and usage intention. A cross-sectional survey of 485 Saudi app users was conducted, and the data were analyzed using confirmatory factor analysis (CFA) and structural equation modeling (SEM). The findings indicate that both technological and gratification-driven constructs significantly impact e-satisfaction and usage intention, which, in turn, positively influence repeat use intention and WOM behavior. This study advances hospitality and technology adoption literature by offering a context-specific model that bridges functional, emotional, and social motivations. Practically, it offers valuable insights for app developers, marketers, and hospitality professionals aiming to enhance user experience, drive retention, and foster digital engagement.20 0Item Restricted Effect of Bonding Agent on Final Shade of Resin Composite: An In Vitro Study(Saudi Digital Library, 2025) Almuhanna, Lama; Rodrigo, Rocha Maia; Gisele, F. NeivaAbstract Objective: The aim of the study was to evaluate the effect of different bonding agents on the final shade of the dental composite. Materials and methods: Two adhesive systems were used: a two-step self-etch adhesive (Clearfil Liner Bond 2V, Kuraray, Noritake, Japan) and a universal adhesive (3M Scotchbond Universal Plus Adhesive, St. Paul, MN, USA). A nanofilled composite of EA1 shade (Filtek XT, 3M ESPE, St. Paul, MN, USA) was used to make 117 discs divided into three groups. Group 1 was the control with no bonding agent, Group 2 received Scotchbond Universal (SB), and Group 3 was treated with the self-etch adhesive (CF). Discs were made using an aluminum mold with three circular openings (diameters 10 mm, thicknesses 0.5, 0.75, and 1 mm). Resin composite was placed in the mold, covered with a glass slide, and light-cured for 20 seconds. After curing, specimens were stored in distilled water at 37°C for 24 hours, then dried before applying the adhesive following the manufacturer's instructions. Color measurements were made using a spectrophotometer. Data were analyzed with Stata MP 17, using two-way ANOVA and Tukey’s post hoc test. Results: Samples' colorimetric properties were analyzed using CIELab parameters (L, a, and b) at three thicknesses (0.5, 0.75, and 1 mm) across Control, SB, and CF groups. In Control, brightness rose from 75.32 ± 0.36 at 0.5 mm to 76.24 ± 0.52 at 0.75 mm, then dropped to 74.31 ± 0.42 at 1 mm; SB showed a similar pattern, while CF remained similar at thinner layers but dropped at 1 mm, indicating thicker samples are less bright. All groups showed increased red (a-values) and yellow hue (b-values) with thickness, causing a yellow shift at higher thicknesses. Color differences (ΔE₀₀) and components (ΔL, Δa, Δb) varied significantly between SB and CF versus Control, with trends confirmed by Tukey’s test (p < 0.05). The Scotchbond group had a non-linear ΔL, while Clearfil’s ΔL consistently decreased. Conclusion: The type of bonding agent and composite thickness critically influence the final restoration shade by affecting light transmission and scattering. Small variations in adhesive application can cause shade mismatches, compromising esthetics, highlighting the need for further research.26 0Item Restricted EVALUATION OF HYDRATION PROTOCOLS FOR HUMAN CORTICAL MINERALIZED PARTICULATE ALLOGRAFTS(Saudi Digital Library, 0025-05-07) Aljowhara, Faraidy; Santana, RonaldoObjective: Bone graft hydration is a critical yet under-explored factor influencing the handling and performance of allograft materials in regenerative procedures. Most manufacturers suggest that biomaterial should be hydrated for at least 30 minutes before use. However, despite widespread clinical use, no standardized hydration protocol exists, and the impact of hydration on the chemical composition, mineralization, and structural integrity of graft materials remains unclear. This study aims to evaluate the physicochemical alterations of mineralized particulate bone grafts following hydration at varying concentrations and time points. Methods: Three commercially available human allograft materials {Straumann Mineralized (SM), Geistlich Mineralized (GM), and Zimmer Mineralized (ZM)} from three different manufacturers, with particle sizes ranging from 250–1000 µm, were examined. The granules were hydrated in 0.9% saline at concentrations of 50 µL and 500 µL and incubated for 1, 10, and 30 minutes. Scanning Electron Microscopy (SEM) was employed to assess hydration-induced structural changes. Chemical composition and molecular alterations were analyzed using Fourier Transform Infrared (FTIR) Spectroscopy and spectral data were processed using second-derivative analysis to improve peak resolution, allowing for the quantification of vibrational bands. Results: SEM analysis revealed no significant differences in surface morphology of the mineralized grafts after hydration. FTIR analysis showed chemical homogeneity across graft materials, with variations in peak intensities reflecting differences in molecular concentrations, mineralization, and collagen integrity. Biomaterial hydration promoted significant selective spectral band increases for all the time points evaluated. Prolonged hydration times did not produce significant or proportional spectral shifts, suggesting a saturation threshold after 1 minute of hydration. Conclusions: Increasing hydration time did not result in significant changes in vibrational bands, suggesting that hydration times longer than 1 minute have minimal impact on the molecular structure of the particulate allografts evaluated.12 0Item Restricted Developing analytical methods for identification of Elongate Mineral Particle (EMP): investigating the possibility of using FTIR spectra and machine learning modeling classification tasks in asbestos containing samples(Saudi Digital Library, 2025-04-28) Alquwayi, Salman; Aaron, BarchowskyBackground: EMPs pose substantial public health risks due to their well-documented associations with respiratory diseases, including asbestosis, lung cancer, and mesothelioma. Current asbestos identification methods, such as polarized light microscopy (PLM) and transmission electron microscopy (TEM), have limitations related to subjectivity, cost, and complexity. Fourier Transform Infrared Spectroscopy (FTIR) offers a promising alternative, but its application in EMP classification remains underexplored. This dissertation investigates the potential of using FTIR in combination with Partial Least Squares Discriminant Analysis (PLS-DA) for improving EMPs detection. Objectives This research aims to (1) develop an analytical method utilizing FTIR-DRIFTS and PLSDA to classify EMPs accurately, (2) investigate and validate the PLS-DA model performance of this method in laboratory-controlled conditions, and (3) improve asbestos monitoring, reduce occupational exposures, and support regulatory compliance in public health and industrial hygiene settings. Methods: Six regulated asbestos reference materials were analyzed using FTIR-DRIFTS. Spectral data were preprocessed and used to train PLS-DA models for classification. The models were validated against reference standards, potential interference, and bulk samples with different mineralogical compositions. The study also assessed the effects of background variability, particle size, and spectral interference on classification accuracy. Results: The developed FTIR-PLS-DA method demonstrated high classification accuracy, correctly identifying asbestos types with minimal misclassification. The technique effectively distinguished EMPs based on their vibrational spectra, with model detection ability reaching as low as 0.0016% by weight for some asbestos classes. Background variability was found to impact model performance, emphasizing the importance of same-day spectral calibration. The model was robust across different particle sizes and sources, though slight misclassification occurred between closely related amphibole types. Conclusion: FTIR-PLS-DA can provide a reliable, reproducible, and cost-effective approach for asbestos and EMP identification. The method minimizes analyst subjectivity and enhances classification accuracy, making it a valuable tool for occupational and environmental monitoring. With a potential integration of handheld IR spectrometers that could further advance on-site asbestos screening, reducing health risks for workers. Public Health Impact: By improving the selectivity and accuracy of EMPs detection, such a method can enhance workplace safety, facilitate regulatory compliance, and support early intervention in asbestos related exposure risks.13 0Item Restricted GEOSPATIAL EXPLORATION OF FLOOD RISKS AND SAFETY MEASURES IN MAKKAH CITY: IMPACT ASSESSMENT ON BOYS' SCHOOL DISTRIBUTIONS FOR INFORMED INFRASTRUCTURE PLANNING(Saudi Digital Library, 2025-06-28) Alsaedi, Rayan; Orimoloye, IsraelThis study investigated the dynamic changes that have occurred in Makkah's educational system as a direct result of significant urban development and an increase in the number of schools. One of the main challenges in effectively managing this growth is paying close attention to safety, future expansion needs, and spatial organization. Thus, the study aims to address this challenge through a multifaceted approach. It seeks to analyze the current distribution of boys' schools in Makkah by unraveling spatial patterns, identifying shortage, and assessing the density of existing schools. Additionally, the study aims to deduce potential locations for future schools and optimize their placement based on identified needs. Quantitative methods that include ArcGIS Pro and Anaconda3 analyses were used in this study. Schools within Makkah's boundaries were analyzed using ArcGIS's Optimized Hotspot Analysis tool, while schools outside Makkah were analyzed using Python in Anaconda3 to find clusters and shortages. Also, the hydrological analysis contributed to identifying schools vulnerable to flood risks by classifying them into different potential risk levels based on their proximity to stream networks, flow accumulation, and terrain slope. This classification was conducted utilizing a hydrological analysis model, which ensures a comprehensive understanding of safety considerations. The study revealed that there was a shortage of schools in the southern and northeastern regions of Makkah, whereas there was a large concentration of schools in central Makkah. In suburban areas, considerable shortages were discovered in Al Jumum and Bahrah governorates, with a significant difference in the number of schools across education levels. The flood risk classification classified six elementary schools and two secondary schools in potential high-risk zones, whereas the majority of high schools were in low or no-risk areas. These findings emphasize the necessity of better school distribution and enhanced safety protocols in areas vulnerable to flooding.Item Restricted MECHANICAL AND PHYSICAL PROPERTIES OF 3D-PRINTED VENEER MATERIALS(Saudi Digital Library, 2025-06-17) NASIR, ADNAN; Russell, Giordano IIObjectives: This study aimed to evaluate and compare the mechanical and physical properties of two 3D-printed dental veneer material, Rodin Envision and SprintRay OnX Tough 2. The primary focus was on determining minimum printable thickness, flexural strength, fracture toughness, wear resistance, translucency, color stability, surface roughness, gloss retention, and filler content by weight. Materials and Methods: Two resin-based materials were analyzed: Rodin Envision (Pac-Dent, USA) and OnX Tough 2 (SprintRay, USA), fabricated using Asiga Max and Sprintray P95 printers, respectively. Specimens were designed and tested following ISO standards. Minimum printable thicknesses tested were 0.1, 0.2, 0.3, 0.4-, and 0.5-mm. Evaluations included three-point flexural strength, fracture toughness, wear resistance (extrapolated to 1 million cycles), translucency, and surface roughness pre- and post-immersion. Color stability was assessed using three staining solutions: coffee, tea, and 0.1 ppm toluidine blue. Gloss retention was measured before and after thermocycling, and filler content was determined using ash burnout. Microstructural analysis was conducted using Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS). Results: Rodin Envision demonstrated significantly superior performance in print precision, mechanical strength, wear resistance, and gloss retention. It achieved accurate prints at 0.2 mm and higher, and exhibited higher flexural strength (155.3 MPa vs. 128.2 MPa) and modulus (5.72 GPa vs. 4.16 GPa). Envision also outperformed OnX Tough 2 in fracture toughness, translucency, and gloss retention. However, OnX Tough 2 showed better color stability in tea and retained lower surface roughness after staining. Filler content analysis revealed higher inorganic loading in Envision (51.73%) compared to OnX Tough 2 (35.3%). Conclusion: Rodin Envision presents superior mechanical and physical properties across most tested domains, making it a more suitable candidate for high-performance esthetic dental restorations. OnX Tough 2 may be preferred in clinical scenarios prioritizing color stability and flexibility. These findings underscore the importance of material selection in optimizing the performance of 3D-printed veneers.Item Restricted MINKOWSKI’S SUCCESSIVE MINIMA AND APPLICATIONS TO NUMBER THEORY(Saudi Digital Library, 2025) Alsaab, Fatimah Hussain; Zvavitch, ArtemIn this thesis, we review a number of crucial objects and tools from classical convex geometry. We pay special attention to investigate the conditions under which convex shapes in Euclidean space contain lattice points. We begin by introducing the fundamental concepts of convexity, followed by an exploration of the geometry of numbers and lattice theory. We then examine two central theorems, Pick’s Theorem and Minkowski’s Theorem, which provide insights into the existence and distribution of lattice points within convex bodies, as well as their relationship to the volume of these bodies. Finally, we discuss several applications related to number theory.Item Restricted Meaningful Online Interactions as a Predictor of Student Learning Outcomes in Online Learning Environments: Moderating Effect of Student Differences(Saudi Digital Library., 2025) Alqarni, Reem; Greg, KesslerThe purpose of this study was to investigate the direct influence of meaningful interactions, as classified by Moore’s interaction model, on student learning outcomes in online learning environments. Specifically, this study explored the predictive relationships between three types of online interactions (learner-instructor interaction (LII), learner-learner interaction (LLI), and learner-content interaction (LCI)) and student learning outcomes, namely student satisfaction and perceived learning in online courses, focusing on their unique and combined contributions. Furthermore, the study examined the moderating effects of student-related variables (gender, prior online learning experience, and academic degree level) on these relationships. The study involved 217 undergraduate and graduate students from the College of Education at Ohio University who had previously enrolled in at least one online course. Data was collected during the Spring semester of 2024. A quantitative, correlational research design was employed. A self-reported survey instrument incorporating validated scales for student satisfaction, perceived learning, and the three types of interactions (learner-instructor interaction (LII), learner-learner interaction (LLI), and learner-content interaction (LCI)) within an online course was administered. A pilot test was conducted to assess the survey's validity and reliability and research procedures, showing strong measurement consistency within the sample. Data analysis utilized multiple regression to examine predictive relationships among the variables. Moderated multiple regression, implemented through Hayes' PROCESS macro and hierarchical regression, was employed to investigate the potential moderating effects of student-related variables on the relationship between interaction types and student outcomes. Results indicated that the three types of interaction (LCI, LII, and LLI) significantly predict SAT and PL in online courses. Among the predictors, LCI demonstrated the strongest and most significant predictor of both student satisfaction and perceived learning, followed by LII, which had a significant impact on SAT but a limited effect on PL. LLI demonstrated a moderate contribution to PL but had a minimal impact on SAT. Furthermore, the moderation analysis revealed that academic degree level and prior online learning experience significantly moderated the relationship between LCI and PL. In contrast, gender did not significantly moderate the relationship between the examined interaction types (LCI and LLI) and perceived learning. Additionally, none of the examined moderators influenced the relationship between interaction types (LCI and LII) and student satisfaction.15 0