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The Digital Image Correlation (DIC) is a non-contact technique that analyses a sequence of images providing full field measurement of displacements and strains over time. The DIC experimental set-up requires a speckle pattern. In this work a new epoxy-based nanocomposite, containing TiO2 nanoparticles and coffee-derived biochar fillers, was developed to obtain an ecofriendly flame-retardant material with suitable mechanical and optical properties for its use as speckle pattern for DIC applications. The optimized formulation is characterized by a uniform distribution of TiO2 and biochar particles and can be employed as self-standing material during the manufacturing of composite reinforcements. The physicochemical properties, mechanical behaviour and fire performances of the nanocomposite are described. The incorporation of the additives in the epoxy resin increases the Young's modulus by around 30% and almost doubles the burn-through time with respect to pristine resin, suggesting a slight condensed phase mechanism arising from the synergistic action of TiO2 and biochar. The effectiveness for creating DIC speckle patterns is validated by comparing the experimental strains measured by means of DIC analysis with those obtained through a traditional technique. Finally, the durability of the speckle patterns was assessed by accelerated thermal aging tests, confirming the potential application of the material in structural health monitoring of composite structures. [ABSTRACT FROM AUTHOR]

Stimulated Raman scattering in transparent glass-ceramics (TGCs) based on bulk nucleating phase Ba2NaNb5O15 were investigated with the aim to explore the influence of micro- and nanoscale structural transformations on Raman gain. TGCs are composed of nanocrystals that are 10–15 nm in size, uniformly distributed in the residual glass matrix. A significant Raman gain improvement for both BaNaNS glass and TGCs with respect to SiO2 glass is demonstrated, which can be clearly related to the nanostructuring process.

Xylose is nowadays converted into xylitol, a popular special chemical sweetener. Xylitol can be used not only in the pharmaceutical and food industries, but also in cosmetics and synthetic resins because of its countless properties. Conventionally, xylitol is produced by slurry reactors operating in batch with dispersed or supported catalysts. Hydrogen is continuously fed to maintain a constant pressure. In this work, the kinetics of the reaction were investigated to find the optimal operating conditions to minimize the by-products obtained. Given the great performances shown by the new Ru/SiO2 sol–gel derived catalyst in glucose hydrogenation, in this work the mentioned catalyst was tested in the hydrogenation of xylose to xylitol both in batch and in continuous production to prove its stability and activity. [ABSTRACT FROM AUTHOR]

Materials that are able to produce free radicals have gained increasing attention for environmental and biomedical purposes. Free radicals, such as the superoxide anion (O2•−), act as secondary messengers in many physiological pathways, such as cell survival. Therefore, the production of free radicals over physiological levels has been exploited in the treatment of different types of cancer, including osteosarcoma (OS). In most cases, the production of reactive oxygen species (ROS) by materials is light-induced and requires the use of chemical photosensitisers, making it difficult and expensive. Here, for the first time, we propose photoluminescent hybrid ZrO2-acetylacetonate nanoparticles (ZrO2-acac NPs) that are capable of generating O2•− without light activation as an adjuvant for the treatment of OS. To increase the uptake and ROS generation in cancer cells, we modify the surface of ZrO2-acac NPs with hyaluronic acid (HA), which recognizes and binds to the surface antigen CD44 overexpressed on OS cells. Since these nanoparticles emit in the visible range, their uptake into cancer cells can be followed by a label-free approach. Overall, we show that the generation of O2•− is toxic to OS cells and can be used as an adjuvant treatment to increase the efficacy of conventional drugs. [ABSTRACT FROM AUTHOR]

Hybrid materials based on amorphous titanium or zirconium oxide with specific organic ligands show oxidative activity toward organic pollutants in the dark, owing to the generation and unusual long-term adsorption of superoxide radical anions on their surfaces. Here an overview of perspectives for the development of these materials and their processing towards technological applications is presented, focusing on the TiO2- acetylacetonate system. First, the tuning and optimization of the sol-gel synthesis conditions is discussed, aimed at yielding the desired products, such as chemical gels or stable sols. Then the thermal stability of the hybrid dried gels is assessed, in relation to their ability to form superoxide radicals. Finally, electrospinning is introduced as an efficient and ecofriendly technique to support the xerogel powders embedding them in a porous nanofiber polymer network. The preliminary characterization of the electrospun composite polyvinylpyrrolidone-hybrid TiO2 reveals potentialities for the realization of air filters or antimicrobial gauzes. [ABSTRACT FROM AUTHOR]

CO2 and H2O can be energy-upgraded through solar thermochemical cycles. Suitable redox materials are reduced in a solar reactor at high temperature (above 1300-1400°C) and afterwards re-oxidised by CO2 and/or H2O flow, thus producing CO and/or H2. Ceria was recognised as one of the most interesting materials for this process. However, high reduction temperature, low re-oxidation kinetics as well as low stability hindered its practical application. In this work, the redox properties of Ce0.75Zr0.25O2 system prepared by hydrothermal synthesis were compared with those of a co-precipitated sample with the same nominal composition used as reference. Samples were characterised by XRD and N2 physisorption; their self-reducibility and CO2 splitting activity were tested in a thermogravimetric balance, while H2O splitting properties were studied in an ad hoc fixed bed reactor on H2 pre-reduced samples. Obtained results proved that the material prepared by hydrothermal synthesis is characterised by both improved reducibility and splitting activity. [ABSTRACT FROM AUTHOR]

Immobilized enzymes are increasingly used in enzymatic microreactors, to encourage applications in different fields: food industry, medical diagnostics, organic synthesis, drug discovery, biosensors. As a matter of facts, microfluidic systems offer many advantages over conventional packed-bed bioreactors, such as higher efficiency, feasibility of multi-enzyme systems, higher mechanical stability, reduced amounts of reagents required [Pirozzi et al., 2016]. In this study β-1,4-xylan obtained from hemicelluloses was used to obtain xylo-oligosaccharides (XOS), the only nutraceutical that can be produced from lignocellulosic biomass. XOS are considered non-digestible food ingredients, and their prebiotic effect of XOS on Bifidobacterium and Lactobacillus species has been recently demonstrated [Aachary et al., 2011; Broekaert et al., 2011; Nacos et al., 2006; Samanta et al, 2015; Vazquez]et al., 2000]. In addition XOS are stable at wide range of pH (2.5-8.0) and temperature (100 °C), they can stimulate the selective growth of the gut microflora, reduce the blood glucose and cholesterol, reduce the pro-carcinogenic enzymes in gastrointestinal tract, and enhance the mineral absorption from large intestine [Aachary et al., 2011; Broekaert et al., 2011; Nacos et al., 2006; Samanta et al, 2015; Vazquez]et al., 2000]. In this view, sol-gel methods were used for the physical entrapment of xylanase from T. lanuginosus. Due to the mild conditions usually adopted for the gel synthesis, enzymes could be added to the initial mixture of precursors and so entrapped within monolithic porous layers in capillary tubes [Pirozzi et al., 2016]. A suitable combination of sol-gel precursors was found for the simultaneous improvement of the monolith adhesion to the tubing internal surfaces and of the catalytic properties of the entrapped enzymes. Specific attention was devoted to the determination of operating conditions suitable to enhance enzyme stability as well as selectivity in terms of XOS produced. [ABSTRACT FROM AUTHOR]