Plasma processing of nanomaterials: emerging technologies for sensing and energy applications

Plasma processing represents an attractive and versatile option for the fabrication of low-dimensional nanomaterials, whose chemical and physical properties can be conveniently tailored for the development of advanced technologies. In particular, Plasma Enhanced-Chemical Vapor Deposition (PE-CVD) is an appealing route to multi-functional oxide nanoarchitectures under relatively mild conditions, owing to the unique features and activation mechanisms of non-equilibrium plasmas. In this context, the potential of plasma-assisted fabrication in advanced nanosystem development is discussed. After a brief introduction on the basic categories of plasma approaches, the perspectives of application to CVD processes are commented, reporting on the growth and characterization of Co3O4 nanomaterials as a case study. Besides examining the interrelations between the material properties and the synthesis conditions, special focus is given to their emerging applications as catalysts for photo-assisted hydrogen production and solid state gas sensors.     

Inertial-magnetic sensors for assessing spatial cognition in infants

This letter describes a novel approach to the assessment of spatial cognition in children. In particular, we present a wireless instrumented toy embedding magneto-inertial sensors for orientation tracking, specifically developed to assess the ability to insert objects into holes. To be used in naturalistic environments (e.g., day cares), we also describe an in-field calibration procedure based on a sequence of manual rotations, not relying on accurate motions or sophisticated equipment. The final accuracy of the proposed system, after the mentioned calibration procedure, is derived by direct comparison with a gold-standard motion tracking device. In particular, both systems are subjected to a sequence of ten single-axis rotations (approximately 90°, back and forth), about three different axes. The rms of the angular error between the two measurements (gold-standard versus proposed systems) was evaluated for each trial. In particular, the average rms error is under 2°. This study indicates that a technological approach to ecological assessment of spatial cognition in infants is indeed feasible. As a consequence, prevention through screening of large number of infants is at reach.     

Steam oxidation and microstructural evolution of rare earth silicate environmental barrier coatings

A primary failure mode for environmental barrier coatings (EBCs) on SiC ceramic matrix composites (CMCs) is the oxidation of the intermediate Si-bond coating, where the formation of SiO₂ at the bond coating–EBC interface results in debonding and spallation. This work compares the microstructure evolution and steam oxidation kinetics of the Si-bond coating beneath yttrium/ytterbium disilicate ((Y/Yb)DS) and ytterbium disilicate/monosilicate (YbDS/YbMS) EBCs to better understand the impact of EBC composition on oxidation kinetics. After 500 1-h cycles at 1350°C, (Y/Yb)DS displayed a decreasing concentration of the monosilicate minor phase and increasing concentration of porosity as furnace cycling time increased, whereas the YbDS/YbMS EBC displayed negligible microstructural evolution. For both EBC systems, thermally grown oxide growth rates in steam were found to increase by approximately an order magnitude compared to dry air oxidation. The (Y/Yb)DS EBC displayed a reduced steam oxidation rate compared to YbDS/YbMS.     

Anthocyanin pattern of several red grape cultivars and wines made from them

A high-performance liquid chromatography (HPLC) method with in-line photodiode array detection was applied to separate anthocyanins from red grape skin extracts of several Spanish cultivars, before and after winemaking, and from finished red wines. Data show that, for every cultivar studied, the anthocyanin pattern of the three materials considered (fresh grape skins, crushed grape skins after winemaking, and finished red wines) is quite different. These results may be explained by taking into account the different chemical structures of each anthocyanin and the degradation reactions that should take place during winemaking. On the other hand, the HPLC fingerprint of every material (fresh grape skins, crushed grape skins after fermentation, and wines) is related to cultivar characteristics. Thus, HPLC determination of the anthocyanin pattern of wines may be used to predict the grape cultivar from which wine was made.     

Role of Biliverdin Reductase A in the Regulation of Insulin Signaling in Metabolic and Neurodegenerative Diseases: An Update

Insulin signaling is a conserved pathway that orchestrates glucose and lipid metabolism, energy balance, and inflammation, and its dysregulation compromises the homeostasis of multiple systems. Insulin resistance is a shared hallmark of several metabolic diseases, including obesity, metabolic syndrome, and type 2 diabetes, and has been associated with cognitive decline during aging and dementia. Numerous mechanisms promoting the development of peripheral and central insulin resistance have been described, although most of them were not completely clarified. In the last decades, several studies have highlighted that biliverdin reductase-A (BVR-A), over its canonical role in the degradation of heme, acts as a regulator of insulin signaling. Evidence from human and animal studies show that BVR-A alterations are associated with the aberrant activation of insulin signaling, metabolic syndrome, liver steatosis, and visceral adipose tissue inflammation in obese and diabetic individuals. In addition, recent findings demonstrated that reduced BVR-A levels or impaired BVR-A activation contribute to the development of brain insulin resistance and metabolic alterations in Alzheimer’s disease. In this narrative review, we will provide an overview on the literature by focusing on the role of BVR-A in the regulation of insulin signaling and how BVR-A alterations impact on cell dysfunctions in both metabolic and neurodegenerative disorders.     

Ag/ZnO nanomaterials as high performance sensors for flammable and toxic gases

Ag/ZnO nanocomposites supported on polycrystalline Al2O3 were synthesized by an unprecedented approach combining plasma enhanced chemical vapor deposition (PE-CVD) of ZnO matrices and the subsequent deposition of Ag nanoparticles (NPs) by radio frequency (RF) sputtering. The system structure, composition and morphology were investigated by glancing incidence x-ray diffraction (GIXRD), secondary ion mass spectrometry (SIMS), field emission scanning electron microscopy (FE-SEM) and energy dispersive x-ray spectroscopy (EDXS). A tailored dispersion and distribution of silver particles could be obtained under mild conditions by the sole variation of the sputtering time. Gas sensing properties toward flammable and toxic gases, both reducing (CH3CH2OH, CH3COCH3) and oxidizing (O3), were investigated in the temperature range 100-400?°C. Beside the high sensitivity, the developed sensors exhibited a response proportional to Ag content, thanks to catalytic and electronic effects promoted by silver NPs. In addition, discrimination between oxidizing and reducing analytes was enabled by a suitable choice of the adopted working temperature.     

Effect of Calcium-Sulphate-Bicarbonate Water in a Murine Model of Non-Alcoholic Fatty Liver Disease: A Histopathology Study

The progression of nonalcoholic fatty liver disease (NAFLD) is associated with alterations of the gut–liver axis. The activation of toll-like receptor 4 (TLR4) pathways by endotoxins, such as lipopolysaccharide (LPS), contributes to liver injury. The aim of the present study was to evaluate the possible beneficial effects of a calcium-sulphate-bicarbonate natural mineral water on the gut–liver axis by evaluating liver and terminal ileum histopathology in a murine model of NAFLD. NAFLD was induced in mice by administrating a methionine-choline-deficient (MCD) diet. The following experimental groups were evaluated: controls (N = 10); MCD+Tap water (MCD; N = 10); MCD+Calcium-sulphate-bicarbonate water (MCD/W_csb; N = 10). Mice were euthanised after 4 and 8 weeks. Liver and terminal ileum samples were collected. Samples were studied by histomorphology, immunohistochemistry, and immunofluorescence. In mice subjected to the MCD diet, treatment with mineral water improved inflammation and fibrosis, and was associated with a reduced number of activated hepatic stellate cells when compared to MCD mice not treated with mineral water. Moreover, MCD/W_csb mice showed lower liver LPS localization and less activation of TLR4 pathways compared to the MCD. Finally, W_csb treatment was associated with improved histopathology and higher occludin positivity in intestinal mucosa. In conclusion, calcium-sulphate-bicarbonate water may exert modulatory activity on the gut–liver axis in MCD mice, suggesting potential beneficial effects on NAFLD.