Youth fitness testing in South African primary school children : national normative data, fitness and fatness, and effects of socioeconomic status

Includes abstract.Includes bibliographical references (p. 173-214).Overweight, obesity and declining levels of physical fitness have been identified as a problem in many developed countries (1). More recently concern has been raised as a result of the rapid increase in the prevalence rates of overweight and obesity in developing nations ((2); (3); (4); (5)). However, little information is available at a national level for South African primary school children. In this thesis, the current nutritional status and baseline measures of physical fitness are established for a large and representative sample of South African primary school children from a range of ethnic and socioeconomic groups. Interactions between nutritional factors and physical fitness are also considered

“I’m hooked on e-cycling, I can finally be active again”: perceptions of e-cycling as a physical activity intervention during breast cancer treatment

Electrically-assisted bicycles (e-bikes) are a means through which to increase individual physical activity (PA) and overcome some commonly reported barriers to engaging in conventional cycling. Fatigue is a common side effect to breast cancer treatment, and the rate of PA engagement drops significantly following a breast cancer diagnosis. The aim of this qualitative study was to examine perceptions of e-cycling as a means of increasing PA in this population. Twenty-four participants (mean age = 57.88 (standard deviation 10.8), 100% female) who have had a breast cancer diagnosis, completed two semi-structured interviews via Zoom. One interview was conducted prior to an e-bike taster session and a second, after the session. Taster sessions were conducted by certified cycling instructors in the community. Interviews were conducted between December 2021 and May 2022. Data were transcribed verbatim and analyzed thematically using NVivo 12 software. An inductive and deductive approach to analysis was adopted. Five themes were generated: (1) Perceived role of e-bikes during treatment, (2) The relationship between e-bikes and fatigue, (3) Cancer-specific considerations, (4) Is e-cycling ‘enough’?, and (5) Optimizing the intervention. Negative perceptions of e-bikes noted before the taster session were altered following riding an e-bike. The multiple levels of assistance made cycling manageable and less impacted by fatigue, thereby enabling individuals to re-establish previous cycling habits. E-cycling may be a suitable option to increase PA behavior amongst individuals being treated for breast cancer, with the potential to overcome many of the barriers of conventional cycling. Enabling this population to trial an e-bike elicits positive physical and psychological responses that may help to promote future engagement

Marginal accuracy of nickel chromium copings fabricated by conventional and accelerated casting procedures, produced with ringless and metal ring investment procedures: A comparative in vitro study

Background: Conventional investing and casting techniques are time-consuming and usually requires 2-4 h for completion. Accelerated nonstandard, casting techniques have been reported to achieve similar quality results in significantly less time, namely, in 30-40 min. During casting, it is essential to achieve compensation for the shrinkage of solidifying alloy by investment expansion. The metal casting ring restricts the thermal expansion of investment because the thermal expansion of the ring is lesser than that of the investment. The use of casting ring was challenged with the introduction of the ringless technique. Materials and Methods: A total of 40 test samples of nickel chromium (Ni-Cr) cast copings were obtained from the patterns fabricated using inlay casting wax. The 20 wax patterns were invested using metal ring and 20 wax patterns were invested using the ringless investment system. Of both the groups, 10 samples underwent conventional casting, and the other 10 underwent accelerated casting. The patterns were casted using the induction casting technique. All the test samples of cast copings were evaluated for vertical marginal gaps at four points on the die employing a stereo optical microscope. Results: The vertical marginal discrepancy data obtained were tabulated. Mean and standard deviations were obtained. Vertical discrepancies were analyzed using analysis of variance and Tukey honestly significantly different. The data obtained were found to be very highly significant (P < 0.001). Mean vertical gap was the maximum for Group II (53.64 μm) followed by Group IV (47.62 μm), Group I (44.83 μm) and Group III (35.35 μm). Conclusion: The Ni-Cr cast copings fabricated with the conventional casting using ringless investment system showed significantly better marginal fit than that of cast copings fabricated from conventional and accelerated casting with metal ring investment and accelerated casting using ringless investment since those copings had shown the least vertical marginal discrepancies among the four methods evaluated in this study

Investigating the Influence of All-Ceramic Prosthetic Materials on Implants and Their Effect on the Surrounding Bone: A Finite Element Analysis

This study aims to assess and compare the impact of Monolithic Zirconia (MZ) and In-Ceram Zirconia (ZP) superstructures on stress distribution within implants and D2/D4 bone densities under 200 N vertical and oblique occlusal loads using three-dimensional finite element analysis via ANSYS WORKBENCH R2. The analysis employed maximum and minimum von Mises stress values. Modeling an implant (4.2 mm diameter, 10 mm length) and abutment (0.47 mm diameter), with an 8 mm diameter and 6 mm length single crown, the research identified lower von Mises stresses in D2 cancellous bone with the MZ model under vertical loading. Conversely, under oblique loading, the ZP model exhibited maximum von Mises stresses in D4 bone around the implant. This underscores the critical need to consider physical and mechanical properties, beyond mere aesthetics, for sustained implant success. The findings highlight the effect of material composition and stress distribution, emphasizing the necessity of durable and effective implant treatments