Unconventional Multi‐Scale Patterning of Titanium Dioxide: A New Tool for the Investigation of Cell–Topography Interactions

Titanium dioxide (TiO₂) is a biocompatible material with important applications in the field of regenerative medicine. Here we show that a multi‐scale hierarchical architecture of TiO₂, realized with sub‐micrometer polystyrene beads as templating agent patterned by “micromolding in capillaries” (MIMICs), is a viable functional tool for the systematic investigation of cell behavior with respect to a complex topographic texture of the substrate. TiO₂ stripes of different width and interconnected porosity whose size ranges from a few hundred to a few tens nanometer, are obtained after thermal treatment of the precursors with concurrent removal of the templating agent. The adhesion and proliferation of two human secondary neural cell lines, i.e., 1321N1 astrocytoma and SH‐SY5Y neuroblastoma, on the patterns is statistically assessed with respect to the TiO₂ stripe width and porosity. Our results show that cells have a strong preference for TiO₂ patterns with respect to glass, the proliferation rate is not affected by cell porosity whereas adhesion is although ligthly, whereas the response of cell density to stripe width is very different in astocytoma cells with respect to neuroblastoma cells.     

Multiple regression analysis of hydrogen sulphide poisoning in molten carbonate fuel cells used for waste-to-energy conversions

Bioenergy addresses three important social concerns: security of energy supply, mitigation of greenhouse gas emissions and development of agriculture. Bioenergy is the energy generated by either direct or indirect combustion of biomass, which is non-fossil organic material of both vegetable and animal origins. Different technologies are currently available for bioenergy production, but fuel cells are one of the most interesting devices because of their environmental benefits and their high efficiency.In particular, molten carbonate fuel cells are suitable devices for waste-to-energy conversion because of their ability to be fed with biogas, which is biomass-derived gas rich in methane and carbon dioxide. Indeed, methane can be internally reformed to hydrogen, carbon dioxide is a safe diluent preventing electrolyte loss, and carbon monoxide acts both as a hydrogen supplier and as an actual fuel.Unfortunately, biogas impurities, such as sulfur, halogen and nitrogen compounds, cause adverse effects on cell performances. The most dangerous impurities are sulfur compounds, among whom hydrogen sulphide is the predominant and the most harmful chemicals. It reacts with nickel-based anode to form nickel sulphides, that block catalytic sites, slowing hydrogen oxidation down, and change the anode wettability in molten carbonates, compromising the optimal electrolyte distribution within cell components.Poisoning mechanism of hydrogen sulphide depends on operating conditions such as current density, anodic gas composition, temperature and pressure. The aim of this work is to study hydrogen sulphide effects on MCFCs by means of multiple regression analysis. The mathematical approach gives us tools to define the main sulfur poisoning mechanism under MCFC operating conditions, quantify the effects of the main parameters affecting poison actions, such as current density, hydrogen and hydrogen sulphide, and identify their mutual interactions. Also it is possible to formulate a multivariate model to predict sulfur poisoning.     

Techno-economic optimisation of hydrogen production by PV - electrolysis: “RenHydrogen” simulation program

The work concerns the optimisation of hydrogen production by electrolysis using renewable energy resources. To achieve this aim, the techno-economic analysis was dedicated to a system composed of PV panels and an electrolyser, including all associated technology such as the chopper circuit¹. The first step was to complete a LabVIEW simulation program which was able to reproduce a photovoltaic (PV) plant connected to the alkaline electrolyser. The virtual instrument was developed on the basis of the models of incident radiation, PV cells and electrolyser. After the indication of PV cell type and number, tilt of all panels, number of strings², latitude and main characteristics of the electrolyser (e.g. nominal power, number of electrolytic cells, working temperature and pressure), the program computes the hydrogen produced, the electrolyser running hours and other data, for a chosen period of the year.Differently tilted photovoltaic panels were considered either directly coupled with the electrolyser or connected via a DC converter between the two systems.The simulation program, called “RenHydrogen”, provides a qualitative calculation of the hydrogen production during the whole year, comparing different technological options and leading to the techno-economic optimisation of the PV-electrolysis system.     

Manufacturing and testing of a HETS module for DEMO divertor

The development of a divertor concept for fusion power plants that is able to grant efficient recovery and conversion of the considerable fraction (～15%) of the total fusion thermal power incident is deemed to be an urgent task to meet in the EU Fast Track scenario. The He-cooled conceptual divertor design is one of the possible candidates. Helium cooling offers several advantages including chemical and neutronic inertness and the ability to operate at higher temperatures and lower pressures than those required for water cooling. The HETS (high-efficiency thermal shield) concept, initially developed by ENEA for water, has been adapted for use with He as coolant. This DEMO divertor concept is based on elements joined in series and protected by a hemispheric dome; it allows an increase of thermal exchange coefficient both for high speed of gas and for “jet impingement” effects of gas coming out from the internal side of hemispheric dome. It has been calculated to be capable of sustaining an incident heat flux of 10 MW/m² when operating at 10 MPa, an inlet He temperature of 600 °C, and an outlet temperature of 800 °C. The presented activity, performed in the frame of EFDA-TW5TRP-001 task, was focused on the manufacturing of a single HETS module and on its thermal–hydraulic testing. The materials used for the HETS module manufacturing were all DEMO-compatible: W for the armor material and the hemispherical-dome, DENSIMET for the exchanger body. The testing is performed by connecting the module to HEFUS3 He loop system that is a facility able to supply the He flow to the required testing conditions: 400 °C, 4–8 MPa and 20–40 g/s. The needed incident heat flux is obtained by RF inducting equipment coupled to an inductor coil installed just over the HETS module. A CFD analysis by ANSYS-CFX was performed in order to predict the thermal–mechanical behavior of the module and a final comparison with the experimental data is required to validate the CFD results. All parameters are monitored and recorded by data acquisition system.     

Stability of Pycnogenol® as an ingredient in fruit juices subjected to in vitro gastrointestinal digestion

BACKGROUND: The enrichment of fruit juices with concentrated polyphenolic extracts is an expedient strategy to compensate possible phenolic loss through gastrointestinal processing. Pycnogenol®, a standardised procyanidin‐rich extract from pine bark, has been proposed as a potential candidate for polyphenol enrichment of foods. In this study the effects of in vitro digestion on the phenolic profile of fruit juices enriched with Pycnogenol® were investigated. RESULTS: After in vitro digestion the level of detectable total phenolic compounds (expressed as gallic acid equivalent) was higher in both pineapple and red fruit juices enriched with Pycnogenol® than in non‐enriched commercial juices. Five phenolic monomeric compounds were identified by high‐performance liquid chromatography, namely chlorogenic acid, caffeic acid, ferulic acid, gallic acid and taxifolin, the last two being predominant. In vitro digestion of both Pycnogenol®‐enriched pineapple and red fruit juices led to a significant (P < 0.05) increase in detectable chlorogenic and ferulic acids, indicating that hydrolysis of more complex molecules occurs. On the other hand, in vitro digestion of non‐enriched juices was associated with a decrease in gallic and caffeic acids in pineapple juice and with a decrease in ferulic acid in red fruit juice. In no case did in vitro digestion increase the amount of detectable phenolic compounds in non‐enriched juices. CONCLUSION: The stability of Pycnogenol® after in vitro gastrointestinal digestion makes it a good choice for phenolic enrichment of fruit juices. Copyright © 2010 Society of Chemical Industry     

Near-infrared benzodiazoles as small molecule environmentally-sensitive fluorophores

The development of fluorophores emitting in the near-infrared spectral window has gained increased attention given their suitable features for biological imaging.In this work,we have optimised a general and straightforward synthetic approach to prepare a small library of near-infrared-emitting C-bridged nitrobenzodiazoles using commercial precursors.C-bridged benzodiazoles have low molecular weight and neutral character as important features that are not common in most nearinfrared dyes.We have investigated their fluorescence response in the presence of a wide array of 60 different biomolecules and identified compound 3i as a potential chemosensor to discriminate between Fe2+and Fe³⁺ions in aqueous media.     

Lifetime reliability-based optimization of reinforced concrete cross-sections under corrosion

This paper presents a lifetime reliability-based approach to the optimization of reinforced concrete (RC) cross-sections in an aggressive environment. The lifetime structural performance is evaluated by using a general methodology for time-variant analysis of RC structures subjected to diffusive attacks from aggressive agents with corrosion of the reinforcement. The lifetime probabilistic optimization is formulated at the cross-sectional level and is aimed to minimize the material cost under a time-dependent constraint on the structural reliability. The optimization problem is solved by combining a discrete gradient-based optimization method with a Monte Carlo simulation. The obtained results demonstrate that in a lifetime-oriented design the amount and location of the steel reinforcement and the value of the concrete cover play a crucial role for the optimal achievement of the desired lifetime structural performance.     

Time for a shift in crop production: embracing complexity through diversity at all levels

A radical shift in our approach to crop production is needed to ensure food security and to address the problems of soil degradation, loss of biodiversity, polluted and restricted water supplies, coupled with a future of fossil fuel limitations and increasingly variable climatic conditions. An interdisciplinary network of European scientists put forward visions for future crop production embracing the complexity of our socio‐ecological system by applying the principle of diversity at all levels from soil micro‐organisms to plant varieties and cropping systems. This approach, integrated with careful deployment of our finite global resources and implementation of appropriate sustainable technology, appears to be the only way to ensure the scale of system resilience needed to cope with many of our concerns. We discuss some of the most important tools such as (i) building soil fertility by recycling of nutrients and sustainable use of other natural and physical resources, (ii) enhancing biological diversity by breeding of crops resilient to climate change and (iii) reconnecting all stakeholders in crop production. Finally, we emphasise some of the changes in agricultural and environmental regulation and policy needed in order to implement the visions. Copyright © 2009 Society of Chemical Industry     

Combined experimental and numerical investigations on the roughness effects on the aerodynamic performances of LPT blades

The aerodynamic performance of a high-load low-pressure turbine blade cascade has been analyzed for three different distributed surface roughness levels (Ra) for steady and unsteady inflows. Results from CFD simulations and experiments are presented for two different Reynolds numbers (300000 and 70000 representative of take-off and cruise conditions, respectively) in order to evaluate the roughness effects for two typical operating conditions.