Luster Pottery from the Thirteenth Century to the Sixteenth Century: A Nanostructured Thin Metallic Film

Luster is a decorative metallic film that was applied on the surface of medieval glazed pottery. It can be obtained via the low-temperature (∼650°C), controlled reduction of copper and silver compounds. In this paper, we show that luster is a thin layered film (200–500 nm thick) that contains metallic spherical nanocrystals dispersed in a silicon-rich matrix and has a metal-free outermost glassy layer that is 10–20 nm thick. Silver nanocrystals seem to be separated from those of copper, forming aggregates 5–100 μm in diameter. This composite structure exhibits optical properties that are dependent on both the particle size and the matrix. Luster is indeed the first reproducible nanostructured thin metallic film that was made by humans.     

Snap-back Analysis of Fracture Evolution in Multi-Cracked Solids Using Boundary Element Method

According to the Linear Elastic Fracture Mechanics criteria, a numerical model is developed to simulate the failure evolution of multi-cracked finite plates by means of an incremental loading procedure. A modified crack length control scheme is used in order to analyse such problems depending on one or more independent parameters. The aim is to provide information about a discontinuous response, such as the snap-back instability, which can be highlighted only by a deformation controlled process. The load vs. displacement curve, included possible snap-back branches, is numerically traced by means of a procedure based on the Displacement Discontinuity Boundary Element Method. With reference to finite plates with ordered crack distributions in plane strain loading conditions, the model is applied in order to analyse the effects of the crack interaction on the fracture evolution. This revised version was published online in July 2006 with corrections to the Cover Date.     

Complex Price Dynamics in a Financial Market with Imitation

In this work a simple financial model with fundamentalists and imitators is being considered. In order to describe the price dynamics of the heterogeneous stock market, a synergetic approach is used and some global bifurcations arising in the model are being studied. It is shown that the fundamental equilibrium point P* may be destabilized through a subcritical Neimark–Sacker bifurcation and that two invariant closed curves, one attracting and one repelling, appear when P* is still stable. This particular bifurcation scenario allows us to show some noticeable features of the market that emerge when the imitation effect is emphasized. Among these features are, for instance, the volatility clusters associated with the presence of multistability (i.e. coexistence of attractors) and the hysteresis phenomenon.     

Ionic liquids as diathermic fluids for solar trough collectors’ technology: A corrosion study

The AISI 304 and AISI 1018 steels (frequently used in solar collectors’ plants) in contact with four different ionic liquids (ILs) suitable as diathermic fluids, were studied. Immersion tests were performed at 220 °C (the working temperature in such plants) for 10 days. The corrosion morphologies of the steels were investigated by scanning electron microscopy coupled with energy dispersive X-ray (EDX) microanalysis and the content of metals in the solution were detected via ICP-OES. The tests showed that the most performing IL is the ethyl-dimethyl-propyl-ammonium-bis(trifluoromethylsulphonyl)imide. The corrosion properties of the two alloys in contact with such IL were investigated by means of Tafel plots and resistance polarization at room temperature in open-to-air vessels.     

Understanding the Selectivity Mechanism of the Human Asialoglycoprotein Receptor (ASGP-R) toward Gal- and Man-type Ligands for Predicting Interactions with Exogenous Sugars

A practical approach for addressing the computer simulation of protein-carbohydrate interactions is described here. An articulated computational protocol was set up and validated by checking its ability to predict experimental data, available in the literature, and concerning the selectivity shown by the Carbohydrate Recognition Domain (CRD) of the human asialoglycoprotein receptor (ASGP-R) toward Gal-type ligands. Some required features responsible for the interactions were identified. Subsequently the same protocol was applied to monomer sugar molecules that constitute the building blocks for alginates and ulvans. Such sugar polymers may supply a low-cost source of rare sugars with a potential impact on several industrial applications, from pharmaceutical to fine chemical industry. An example of their applicative exploitation could be given by their use in developing biomaterial with adhesion properties toward hepatocytes, through interaction with the ASGP-R. Such a receptor has been already proposed as a target for exogenous molecules, specifically in the case of hepatocytes, for diagnostic and therapeutic purposes. The DOCK5.2 program was used to search optimal locations of the above ligands of interest into CRD binding site and to roughly estimate interaction energies. Finally, the binding ΔG of theoretical protein-ligand complexes was estimated by using the DelPhi program in which the solvation free energy is accounted for with a continuum solvent model, by solving the Poisson-Boltzmann equation. The structure analysis of the obtained complexes and their ΔG values suggest that one of the sugar monomers of interest shows the desired characteristics.     

Functional Properties of Plasticized Bio-Based Poly(Lactic Acid)_Poly(Hydroxybutyrate) (PLA_PHB) Films for Active Food Packaging

Fully bio-based and biodegradable active films based on poly(lactic acid) (PLA) blended with poly(3-hydroxybutyrate) (PHB) and incorporating lactic acid oligomers (OLA) as plasticizers and carvacrol as active agent were extruded and fully characterized in their functional properties for antimicrobial active packaging. PLA_PHB films showed good barrier to water vapor, while the resistance to oxygen diffusion decreased with the addition of OLA and carvacrol. Their overall migration in aqueous food simulant was determined and no significant changes were observed by the addition of carvacrol and OLA to the PLA_PHB formulations. However, the effect of both additives in fatty food simulant can be considered a positive feature for the potential protection of foodstuff with high fat content. Moreover, the antioxidant and antimicrobial activities of the proposed formulations increased by the presence of carvacrol, with enhanced activity against Staphylococcus aureus if compared to Escherichia coli at short and long incubation times. These results underlined the specific antimicrobial properties of these bio-films suggesting their applicability in active food packaging.     

Optimisation of cake fat quantity and composition using response surface methodology

The influence of fat quantity and composition on the characteristics of a chemically leavened baked product was investigated, applying a central composite design combined with response surface methodology. Fats were blends of palm oil and palm olein with different slip melting points (from 36.3 to 11.3 °C, in dependence of increasing olein content). Fat content (from 5.3% to 30.7% on batter) and percentage of olein in the fat blend (from 42.7% to 92.2%) were varied. The increase of fat quantity enhanced cake softness, while lowering the volume; higher olein contents also decreased cake firmness. An optimised formulation containing 19.7% fat with 92% olein in the fat blend and showing good structural properties, comparable to those of a 18% butter reference cake, was identified. The optimised and the butter cake showed specific volume of 2.25 and 2.23 cm³ g^?1, respectively, and load at 25% strain of 7.68 and 5.63 N. These results demonstrated the possibility to replace butter with a liquid vegetable fat blend, thus increasing unsaturated fat content and reducing total cholesterol in the product.     

The Fight against the Influenza A Virus H1N1: Synthesis,Molecular Modeling,and Biological Evaluation of Benzofurazan Derivatives as Viral RNA Polymerase Inhibitors

The influenza RNA polymerase complex, which consists of the three subunits PA, PB1, and PB2, is a promising target for the development of new antiviral drugs. A large library of benzofurazan compounds was synthesized and assayed against influenza virus A/WSN/33 (H1N1). Most of the new derivatives were found to act by inhibiting the viral RNA polymerase complex through disruption of the complex formed between subunits PA and PB1. Docking studies were also performed to elucidate the binding mode of benzofurazans within the PB1 binding site in PA and to identify amino acids involved in their mechanism of action. The predicted binding pose is fully consistent with the biological data and lays the foundation for the rational development of more effective PA–PB1 inhibitors.