Der Weg zum Kompetenzzentrum für Adipositas und metabolische Chirurgie – Erfahrungen aus 2 verschiedenen Kliniken

Die Chirurgie - Bei hoher Prävalenz, stetig steigender Inzidenz der Adipositas und nachgewiesener Wirksamkeit adipositaschirurgischer Operationen (Ops) nehmen die Anzahl dieser OPs und die...     

Mechanical Properties,Crack Width,and Propagation of Waste Ceramic Concrete Subjected to Elevated Temperatures: A Comprehensive Study

Waste ceramic concrete (WOC) made from waste ceramic floor tiles has several economic and environmental benefits. Fire is one of the most common disasters in buildings, and WOC is a brittle construction material; therefore, the mechanical properties of WOC structures under high temperatures should be considered. According to previous studies, hybrid fiber can further reduce damage to concrete under high temperatures. Meanwhile, crack width and propagation are among the key characteristics of concrete materials that need to be considered, but few studies have focused on their behavior when subjected to elevated temperatures. The new concrete materials proposed by the authors are WOC and WOC-Hybrid. WOC was prepared with Natural Coarse Aggregates (NCA), Natural Fine Aggregate (NFA), Ordinary Portland Cement (OPC 43 grade), and ceramic waste tiles with 20% replacements for coarse aggregates, 10% replacements for fine aggregates, and 10% replacement for cement. In contrast, WOC-Hybrid was prepared with the addition of hybrid fiber (1% crimped steel fiber and 1% polyvinyl alcohol fiber) in WOC. The specimens were exposed to temperatures of 100–300 °C, and then the specimens were tested for tensile and compressive strength. The present study aims to find a new method to improve concrete resistance to elevated temperatures at the lowest costs by experimental and computational analysis via machine learning models. The application of machine learning models such as artificial neural networks (ANN) and multiple linear regression (MLR) was employed in this study to predict the compressive and tensile strength of concrete. The linear coefficient correlation (R²) and mean square error (MSE) were evaluated to investigate the performance of the models. Based on the experimental analysis, the results show that the effect of hybrid fiber on the crack width and propagation is greater than that on the crack width and propagation of WOC and PC after exposure to high temperatures. However, the enhanced effect of hybrid fiber on the mechanical properties, rack width, and propagation decreases after subjecting it to a high-temperature treatment, owing to the melting and ignition of hybrid fibers at high temperatures. Regarding the computational analysis, it was found that the developed MLR model shows higher efficiency than ANN in predicting the compressive and tensile strength of PC, WOC, and WOC-Hybrid concrete.     

Prediction of Rockfill Materials’ Shear Strength Using Various Kernel Function-Based Regression Models—A Comparative Perspective

The mechanical behavior of the rockfill materials (RFMs) used in a dam’s shell must be evaluated for the safe and cost-effective design of embankment dams. However, the characterization of RFMs with specific reference to shear strength is challenging and costly, as the materials may contain particles larger than 500 mm in diameter. This study explores the potential of various kernel function-based Gaussian process regression (GPR) models to predict the shear strength of RFMs. A total of 165 datasets compiled from the literature were selected to train and test the proposed models. Comparing the developed models based on the GPR method shows that the superlative model was the Pearson universal kernel (PUK) model with an R-squared (R²) of 0.9806, a correlation coefficient (r) of 0.9903, a mean absolute error (MAE) of 0.0646 MPa, a root mean square error (RMSE) of 0.0965 MPa, a relative absolute error (RAE) of 13.0776%, and a root relative squared error (RRSE) of 14.6311% in the training phase, while it performed equally well in the testing phase, with R² = 0.9455, r = 0.9724, MAE = 0.1048 MPa, RMSE = 0.1443 MPa, RAE = 21.8554%, and RRSE = 23.6865%. The prediction results of the GPR-PUK model are found to be more accurate and are in good agreement with the actual shear strength of RFMs, thus verifying the feasibility and effectiveness of the model.     

Colour Change of Sustainable Concrete Containing Waste Ceramic and Hybrid Fibre: Effect of Temperature

Construction and demolition (C&D) waste was considered as zero value materials and, as a result, most C&D waste materials ended up in landfills, eventually constituting environmental issues. Therefore, it is important to explore the potential of such C&D waste materials for concrete production. Thus, this research effort aims to find a new method to improve sustainable concrete properties exposed to elevated temperatures at the lowest costs and identify the relationship between temperature change and a change in colour in a heat-exposed concrete structure. Therefore, this study explored the behaviour of three types of concrete: plain concrete (PC), waste ceramic optimal concrete (WOC), and waste ceramic optimal concrete reinforced by hybrid fibre (WOC-Hybrid) in ambient and elevated temperature. The study shows that colour change in a concrete structure exposed to high temperature has a consistent relationship, where it has been found that the colour alteration is of great interest because its appearance usually coincides with the onset of a significant loss of concrete strength as a result of elected temperatures. Overall, it can be considered that waste ceramic materials reinforced by hybrid fibres can be used for concrete production, and by doing so, the negative impact of these wastes on the environment can be controlled as well as fortify the mechanical properties.     

Psychometric Properties of Osteoporosis Knowledge Tool and Self-Management Behaviours Among Malaysian Type 2 Diabetic Patients

Osteoporosis is a major growing public health problem and it is clear that much needs to be done to bridge the gap between patients and practitioners. However, the educator must have a valid and reliable tool to evaluate the effectiveness of the teaching and learning that are done. Osteoporosis Knowledge Tool (OKT) provides an important strategy for healthcare professionals to start early intervention for patients who are at risk of osteoporosis. The aims of this study were to translate and examine the psychometric properties of the Malaysian version of the Osteoporosis Knowledge Tool (OKT-M) among 250 type 2 diabetes patients and to assess factors that affect diabetic patients’ osteoporosis knowledge. The OKT English version was translated and validated using the internationally accepted and recommended methodology. The sensitivity and specificity of OKT-M was calculated using receiver operating characteristic curve analysis. The face and content validity showed acceptable results. Internal consistency, test–retest reliability, mean difficulty factor and discriminatory power values were 0.72, 0.83, 0.47 ± 0.16 and 0.96, respectively. The cut-off point of the OKT-M to predict osteoporosis/osteopenia was 14 with optimal sensitivity (84.1 %) and specificity (85.5 %). Regression analysis revealed that health belief, self-efficacy and some demographic data had an impact on the OKT-M. The findings of this validation study indicate that the OKT-M is a reliable and valid tool with good psychometric properties in the Malaysian setting. The OKT-M is an appropriate tool for application in clinical setting to identify patients need for a bone health-promoting intervention regarding lifestyle behaviour changes.     

Suspected malignant hyperthermia in a child with laminin alpha2 (merosin) deficiency in the absence of a triggering agent

Malignant hyperthermia (MH) is an inherited disorder of the skeletal muscles that can be triggered by many anesthetic agents. MH has different presentations and manifestations that makes it difficult to diagnose. Patients with laminin alpha2 deficiency have never been reported to be susceptible to MH. We present a suspected MH episode in the absence of classic triggering agents in a 7-year-old boy with laminin alpha2 (merosin) deficiency and congenital muscular dystrophy. The episode was diagnosed using the MH clinical grading scale and responded well to prompt management with dantrolene. We conclude that patients with laminin alpha2 deficiency may be susceptible to MH, and early suspicion and rapid treatment is vital in the management of MH. Anesthesiologists should be prepared to treat MH in susceptible patients even in the absence of a classical triggering agent.