Search Results (3)

In this study, we examined the microclimates at eight entrances to a karst system distributed between an elevation of 812 and 906 m in Southern Spain. The karst system, characterised by subvertical open tectonic joints that form narrow shafts, developed on the slope of a mountainous area with a Mediterranean climate and strong chimney effect, resulting in an intense airflow throughout the year. The airflows modify the entrance temperatures, creating a distinctive pattern in each opening that changes with the seasons. The objective of this work is to characterise the outflows and find simple temperature-based parameters that provide information about the karst interior. The entrances were monitored for five years (2017–2022) with temperature–humidity dataloggers at different depths. Other data collected include discrete wind measurements and outside weather data. The most significant parameters identified were the characteristic temperature (T_y), recorded at the end of the outflow season, and the rate of cooling/warming, which ranges between 0.1 and 0.9 °C/month. These parameters allowed the entrances to be grouped based on the efficiency of heat exchange between the outside air and the cave walls, which depends on the rock-boundary geometry. This research demonstrates that simple temperature studies with data recorded at selected positions will allow us to understand geometric aspects of inaccessible karst systems. Dynamic high-airflow cave systems could become a natural source of evidence for climate change and its effects on the underground world. Full article

The pathogenesis of non-alcoholic fatty liver disease (NAFLD), the most prevalent chronic liver disease, is associated with zinc deficiency. Previous studies show zinc supplementation improves steatosis and glucose metabolism, but its therapeutic effects in patients with established NAFLD remain unclear. We developed an in vivo model to characterize the effects of zinc supplementation on high-fat diet (HFD) induced NAFLD and hypothesized that the established NAFLD would be attenuated by zinc supplementation. Male C57BL/6J mice were fed a control diet or HFD for 12 weeks. Mice were then further grouped into normal and zinc-supplemented diets for 8 additional weeks. Body composition and glucose tolerance were determined before and after zinc supplementation. At euthanasia, plasma and liver tissue were collected for characterization and downstream analysis. As expected, 12 weeks of HFD resulted in reduced glucose clearance and altered body composition. Eight weeks of subsequent zinc supplementation did not alter glucose handling, plasma transaminases, steatosis, or hepatic gene expression. Results from our model suggest 8-week zinc supplementation cannot reverse established NAFLD. The HFD may have caused NAFLD disease progression beyond rescue by an 8-week period of zinc supplementation. Future studies will address these limitations and provide insights into zinc as a therapeutic agent for established NAFLD. Full article

In this study, (Gd_0.9Yb_0.1)₂Zr₂O₇ (GYbZ)/yttria-stabilized zirconia (YSZ) double-ceramic-layer (DCL) thermal barrier coatings (TBCs) were prepared by plasma spray-physical vapor deposition (PS-PVD). The microstructure, mechanical performance, and thermal shock behavior of coatings prepared with spraying distances of 600, 800, and 1000 mm were investigated. The GYbZ coating prepared with a spraying distance of 600 mm showed a closely packed columnar structure. However, the GYbZ coatings prepared with spraying distances of 800 and 1000 mm showed a quasi-columnar structure. The GYbZ coating prepared with a spraying distance of 800 mm had the thickest columnar crystals with obvious inter-columnar gaps. In addition, this coating exhibited excellent mechanical performance and the best thermal shock resistance. The primary failure patterns appearing during thermal shocking on the surface of TBCs can be classified into the following five types: caves, exfoliation, delamination cracks, spalled areas, and radiate cracks. Furthermore, the failure behavior of these coatings in water-quenching tests is clarified. Full article