Evaluation of the wettability of Al-Pb and Al-Sn alloys with SiC and Al2O3 particulates by means of pressure infiltration

The wettability of SiC and Al₂O₃ particulates by Al-Pb and Al-Sn alloys has been evaluated by means of pressure infiltration. All infiltrations were carried out in air. The resulting threshold pressures decrease logarithmically with the content of the alloying element, similarly to the experimental data for the surface tension of these alloys reported in the literature. In the case of SiC, the threshold pressure decreases with the alloy content at a higher rate than the surface tension. In contrast, although the results for the alumina particulates are less clear, the tendency seems to be the opposite. These results are interpreted in terms of differences in wettability of silicon carbide and alumina particulates by oxidized aluminium-tin and aluminium-lead alloys.     

A systematic review on the use of immersive virtual reality to train professionals

Multimedia Tools and Applications - The main goal of this systematic review is to synthesize existing evidence on the use of immersive virtual reality (IVR) to train professionals as well as to...     

Virtual reality in training: an experimental study with firefighters

Multimedia Tools and Applications - Training with Virtual Reality (VR) can bring several benefits, such as the reduction of costs and risks. We present an experimental study that aims to evaluate...     

Antibiotic prophylaxis in elective neurosurgery. Epidemiological study

The authors present an epidemiological study of patients who have undergone elective neurosurgery and who have been treated with different types of antibiotics throughout a ten year time span. From the statistic analysis of the different parameters taken into consideration (administering modalities of the short-term and long-term antibiotic, type of sepsis encountered, isolated microorganisms) the authors show, as a result, that the long-term antibiotic prophylaxis is a clearly improper method; the short-term prophylaxis is a correct method the effect of which is, however, still controversial as it does not modify a natural low percentage of infections in elective neurosurgery. The role given to the antibiotic seems much less important compared with the adoption of correct antiseptic measures and of proper nursing.     

Factors affecting pressure infiltration of packed SiC particulates by liquid aluminum

Pressure infiltration is being currently used to evaluate the wettability of ceramic particles and fibers by liquid metals. The objective of this work is to investigate the effect of type and surface condition of the particulates and infiltration atmosphere on pressure infiltration of packed SiC particulates by pure liquid aluminum. Fourteen SiC particulates from five different suppliers, of green (high purity) and black (low purity) types, were used. Two of the particulates were subjected to either low- or high-temperature heat treatments in order to either burn organic residues or promote oxidation. Infiltrations were carried out in air, argon, argon/hydrogen, and nitrogen/hydrogen atmospheres. The results indicate that the threshold pressure does not depend appreciably on the type of particulate. A heat treatment at 600 ‡C improves the infiltration performance of particulates having a large amount of organic residues, whereas oxidation at 1000 ‡C decreases the threshold pressure. The results also illustrate the effects of the infiltration atmosphere; in particular, it is shown that inert or reducing atmospheres improve wettability. Formerly Research Associate with Industrial Espaˉnola del Aluminio, Centro de Investigación y Desarrollo     

Lung Extracellular Matrix Hydrogels Enhance Preservation of Type II Phenotype in Primary Alveolar Epithelial Cells

One of the main limitations of in vitro studies on lung diseases is the difficulty of maintaining the type II phenotype of alveolar epithelial cells in culture. This fact has previously been related to the translocation of the mechanosensing Yes-associated protein (YAP) to the nuclei and Rho signaling pathway. In this work, we aimed to culture and subculture primary alveolar type II cells on extracellular matrix lung-derived hydrogels to assess their suitability for phenotype maintenance. Cells cultured on lung hydrogels formed monolayers and maintained type II phenotype for a longer time as compared with those conventionally cultured. Interestingly, cells successfully grew when they were subsequently cultured on a dish. Moreover, cells cultured on a plate showed the active form of the YAP protein and the formation of stress fibers and focal adhesions. The results of chemically inhibiting the Rho pathway strongly suggest that this is one of the mechanisms by which the hydrogel promotes type II phenotype maintenance. These results regarding protein expression strongly suggest that the chemical and biophysical properties of the hydrogel have a considerable impact on the transition from ATII to ATI phenotypes. In conclusion, culturing primary alveolar epithelial cells on lung ECM-derived hydrogels may facilitate the prolonged culturing of these cells, and thus help in the research on lung diseases.