a b s t r a c tIt is reported in this work the development and study of the optical and structural properties of a solar selective absorber cermet based on AlSiO x :W. A four-layer composite film structure, W/AlSiO x :W(HA)/ AlSiO x :W(LA)/AlSiO x , was deposited on stainless steel substrates using the magnetron sputtering deposition method. Numerical calculations were performed to simulate the spectral properties of multilayer stacks with varying metal volume fraction cermets and film thickness. The chemical analysis was performed using X-ray photoelectron spectroscopy and the results show that in the high metal volume fraction cermet layer, AlSiO x :W(HA), about one third of W atoms are in the W 0 oxidation state, another third in the W x+ oxidation state and the last third in the W 4+ , W 5+ and W 6+ oxidation states. The X-ray diffractograms of AlSiO x :W layers show a broad peak indicating that both, W and AlSiO x , are amorphous. These results indicate that this film structure has a good spectral selective property that is suitable for solar thermal applications, with the coatings exhibiting a solar absorptance of 94-95.5% and emissivities of 8-9% (at 100°C) and 10-14% (at 400°C). The samples were subjected to a thermal annealing at 450°C, in air, and 580°C, in vacuum and showed very good oxidation resistance and thermal stability. Morphological characterizations were carried out using scanning electron microscopy and atomic force microscopy. Rutherford Backscattering experiments were also performed to analyze the tungsten depth profile.

In this study, composite scaffolds based on poly(caprolactone) (PCL) and non‐covalently functionalized few‐layer graphene (FLG) were manufactured by an extrusion‐based system for the first time. For that, functionalized FLG powder was obtained through the evaporation of a functionalized FLG aqueous suspension prepared from a graphite precursor. Cryomilling was shown to be an efficient mixing method, producing a homogeneous dispersion of FLG particles onto the PCL polymeric matrix. Thereafter, fused deposition modeling (FDM) was used to print 3D scaffolds and their morphology, thermal, biodegradability, mechanical, and cytotoxicity properties were analysed. The presence of functionalized FLG demonstrated to induce slight changes in the microstructure of the scaffold, did not affect the thermal stability and enhanced significantly the compressive modulus. The composite scaffolds presented a porosity of around 40% and a mean pore size in the range of 300 μm. The cell viability and proliferation of SaOs‐2 cells were assessed and the results showed good cell viability and long‐term proliferation onto produced composite scaffolds. Therefore, these new FLG/PCL scaffolds comprised adequate morphological, thermal, mechanical, and biological properties to be used in bone tissue regeneration.

The action of demineralized bovine bone matrix on bone neoformation in rats submitted to experimental alcoholism ABSTRACTThe objective of this study was to evaluate whether demineralized bovine bone (Gen-ox ® ) alters bone neoformation in rats submitted to alcoholism. Forty male rats were separated into two groups of 20 rats and distributed as follows: Group E1, which received 25% ethanol and a surgical cavity filled only by a blood clot, and Group E2, which received 25% ethanol and a surgical cavity filled with Gen-ox ® . The animals were euthanized at 10, 20, 40 and 60 days after surgery and necropsy was performed. The histomorphological and histometric analyses of the area of connective tissue and bone neoformation showed that the reorganization of the bone marrow and full repair of the surgical cavity in Group E1 occurred more quickly than in Group E2. It was also noted that in the final period the animals in Group E2 showed areas of connective tissue and thick bone trabeculae around the particles of the implant. It can be concluded that the use of Gen-ox ® delayed the process of bone repair in alcoholic rats, although it can be used as filling material because it shows osteoconductive activity, as evidenced by bone tissue formation around the graft particles.

In this study, Ta 1-x O x coatings were deposited by reactive magnetron sputtering aiming at the enhancement of the electrochemical stability stainless steel 316L. The coatings were produced using variable oxygen content in order to determine its influence on the films morphological features and corrosion resistance. Structural and morphological characteristics were correlated with the corrosion behavior in artificial saliva. Potentiodynamic and electrochemical impedance spectroscopy tests were complemented with X-ray photoelectron spectroscopy to determine the electrochemical behavior of the coatings. The results reveal a more protective behavior of the coatings as the oxygen amount increases in the films, as well as pitting inhibition in the coated stainless steel, independently of the film composition. A synergetic effect between Ta 2 O 5 and phosphate-based passive layers is suggested as the protective mechanisms of the coatings; while the more active electrochemical behavior of low oxygen content films is evidenced as a consequence of the metallic tantalum on the surface with a more open morphology and larger density of defects on the surface.2016 Published by Elsevier Ltd.