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BackgroundA reduced left atrial (LA) strain correlates with the presence of atrial fibrillation (AF). Conventional atrial strain analysis uses two-dimensional (2D) imaging, which is, however, limited by atrial foreshortening and an underestimation of through-plane motion. Retrospective gated computed tomography (RGCT) produces high-fidelity three-dimensional (3D) images of the cardiac anatomy throughout the cardiac cycle that can be used for estimating 3D mechanics. Its feasibility for LA strain measurement, however, is understudied.AimThe aim of this study is to develop and apply a novel workflow to estimate 3D LA motion and calculate the strain from RGCT imaging. The utility of global and regional strains to separate heart failure in patients with reduced ejection fraction (HFrEF) with and without AF is investigated.MethodsA cohort of 30 HFrEF patients with (n = 9) and without (n = 21) AF underwent RGCT prior to cardiac resynchronisation therapy. The temporal sparse free form deformation image registration method was optimised for LA feature tracking in RGCT images and used to estimate 3D LA endocardial motion. The area and fibre reservoir strains were calculated over the LA body. Universal atrial coordinates and a human atrial fibre atlas enabled the regional strain calculation and the fibre strain calculation along the local myofibre orientation, respectively.ResultsIt was found that global reservoir strains were significantly reduced in the HFrEF + AF group patients compared with the HFrEF-only group patients (area strain: 11.2 ± 4.8% vs. 25.3 ± 12.6%, P = 0.001; fibre strain: 4.5 ± 2.0% vs. 15.2 ± 8.8%, P = 0.001), with HFrEF + AF patients having a greater regional reservoir strain dyssynchrony. All regional reservoir strains were reduced in the HFrEF + AF patient group, in whom the inferior wall strains exhibited the most significant differences. The global reservoir fibre strain and LA volume + posterior wall reservoir fibre strain exceeded LA volume alone and 2D global longitudinal strain (GLS) for AF classification (area-under-the-curve: global reservoir fibre strain: 0.94 ± 0.02, LA volume + posterior wall reservoir fibre strain: 0.95 ± 0.02, LA volume: 0.89 ± 0.03, 2D GLS: 0.90 ± 0.03).ConclusionRGCT enables 3D LA motion estimation and strain calculation that outperforms 2D strain metrics and LA enlargement for AF classification. Differences in regional LA strain could reflect regional myocardial properties such as atrial fibrosis burden.

In this work, untreated/treated sisal fibre (SF)-reinforced sodium alginate composites for three different concentrations (1.5%, 2%, and 2.5%) are fabricated by the hand lay-up method, and the variations in mechanical properties such as tensile strength, flexural strength, and impact strength are studied. The treated and untreated composites are analysed and compared using scanning electron microscope to study the surface morphology. Energy-dispersive spectroscopic analysis is carried out to evaluate the elemental compositions. Fourier transform infrared spectroscopic analysis is conducted to determine the interaction between fibres and matrix material. The thermal observations such as differential scanning calorimetry and thermogravimetric analysis showed only slight variations between the untreated and treated SF composites. The results of this work indicate that untreated sample with the maximum sodium alginate gum concentration had significantly enhanced mechanical properties and low moisture absorption rate. Biodegradation test inferred that it was superior for the treated fibre rather than the untreated fibre composites. The primary objective of this work is to assess the suitability of these composites for non-structural engineering applications.

Background: With increasing accessibility to the virtual world, behavioral addiction is an emerging global concern among children and adolescents. Understanding attitudes and perceptions regarding behavioral addictions is critical to formulate appropriately tailored and meaningful interventions. This review aims to widen the scope of understanding behavioral addictions, by synthesizing findings from qualitative studies on perspectives, experiences, and key processes across the spectrum of behavioral addictions among children and adolescents. Methods: We conducted systematic search in PubMed and Google Scholar using keywords pertinent to qualitative research in behavioral addictions, adhering to enhancing transparency in reporting the synthesis of qualitative research guidelines. Eighteen studies were included after thorough screening of studies. We followed the analytical approach described by Petticrew and Roberts for thematic comparative synthesis. Results: There were five principal themes that articulate the experiential realities of children and adolescents in the context of behavioral addictions. They are (1) high-risk environment as a vulnerability: etiopathogenetic model for gambling, (2) attitudes toward behavioral addiction across the spectrum, (3) awareness, (4) perceived impact, and (5) perspectives and attitudes toward other's engagement in addictive behaviors. Conclusion: The findings have implications for public health policies such as promoting a supportive macrosystem while curtailing accessibility to activities and platforms of high addictive potentials. Future research in this area should include multiple stakeholder perspectives, perspectives of younger children and early adolescents, integration with quantitative findings, and studying the impact of particularly high-risk situations, such as the COVID-19 pandemic, to inform recommendations and policies, for comprehensive, multilevel, and multisystemic interventions.

To promote the development of critical thinking abilities in an introductory undergraduate humanities course in the context of mass higher education, we implemented a course design that employed a series of scenario-based multiple-choice questions (MCQs) and informal peer discussions. Using an online survey to gather perception data and self-reported behavioral data, this study examines the extent to which the course design was effective at promoting critical thinking and student experience. Deductive analysis of students' qualitative responses indicate that the course design was successful in promoting students' development of critical thinking. Both deductive and inductive analysis of students' qualitative responses also suggest that students largely had favorable attitudes towards this course design, though there are also some who express concerns. Our design may be useful for instructors and instructional designers aiming to promote critical thinking and learning in university courses.