Evaluation of the repair on multiple leaf stone masonry by acoustic emission

Aim of this research was to evaluate the possible application of the AE technique to study the response of multiple leaf masonry repaired with different techniques. The results of shear tests carried out on three specimens repaired after failure are presented on an explorative basis; on two of them the acoustic emission (AE) technique was also used. Through a number of sensors and by triangulation, this technique makes it possible to identify the location of the damage, unknown initially, and subsequently to assess the stability of its evolution. Using the AE technique the area of the material where the cracks propagated during shear tests was identified. These analyses made it possible to evaluate the effectiveness of repair interventions through parameters other than stress and strain, and contributed to the identification of the most suitable methodology for their optimisation.     

Iterative flattening search for resource constrained scheduling

Iterative flattening search (ifs) is a meta-heuristic strategy for solving multi-capacity scheduling problems. Given an initial solution, ifs iteratively applies: (1) a relaxation-step, in which a subset of scheduling decisions are randomly retracted from the current solution; and (2) a flattening-step, in which a new solution is incrementally recomputed from this partial schedule. Whenever a better solution is found, it is retained, and, upon termination, the best solution found during the search is returned. Prior research has shown ifs to be an effective and scalable heuristic procedure for minimizing schedule makespan in multi-capacity resource settings. In this paper we experimentally investigate the impact on ifs performance of algorithmic variants of the flattening step. The variants considered are distinguished by different computational requirements and correspondingly vary in the type and depth of search performed. The analysis is centered around the idea that given a time bound to the overall optimization procedure, the ifs optimization process is driven by two different and contrasting mechanisms: the random sampling performed by iteratively applying the “relaxation/flattening” cycle and the search conducted within the constituent flattening procedure. On one hand, one might expect that efficiency of the flattening process is key: the faster the flattening procedure, the greater the number of iterations (and number of sampled solutions) for a given time bound; and hence the greater the probability of finding better quality solutions. On the other hand, the use of more accurate (and more costly) flattening procedures can increase the probability of obtaining better quality solutions even if their greater computational cost reduces the number of ifs iterations. Comparative results on well-studied benchmark problems are presented that clarify this tradeoff with respect to previously proposed flattening strategies, identify qualitative guidelines for the design of effective ifs procedures, and suggest some new directions for future work in this area.     

Pellets of MgH2-based composites as practical material for solid state hydrogen storage

Hydrogenation properties and mechanical stability of pellets made starting from compressed ball-milled MgH₂ powders mixed with catalysts (Nb₂O₅ and graphite) and a binding agent (aluminium powder) have been investigated. Structural characterization with X-ray diffraction and gas–solid reaction kinetic and thermodynamic tests with a Sievert's apparatus have been done on the samples up to 50 hydrogen absorption/desorption (a/d) cycles. The best cycling behaviour and mechanical strength stability have been observed for pellets of catalysed MgH₂ powders added with 5 wt% aluminium annealed in vacuum at 450 °C before starting the a/d cycles. This mechanical stability to cycles has been attributed to the formation of a solid solution of aluminium in magnesium.     

Evaluation and Improvement of Extraction Methods for the Analysis of Aflatoxins B1, B2, G1 and G2 from Naturally Contaminated Maize

The extraction procedure for aflatoxin determination in maize is based on a methanol–water (8 + 2 v/v) or an acetone–water (85 + 15 v/v) mixture. Initially, the extraction efficiency of two solvents was evaluated for each aflatoxin. Different results were obtained for highly contaminated maize: significantly higher levels of aflatoxin B₁ were obtained by acetone–water, on the contrary higher levels of aflatoxin G₂ were achieved by methanol–water. Then, acetone–water mixtures in different proportions (7 + 3, 6 + 4 and 5 + 5 v/v) were tested to improve the extraction of aflatoxin G₂. Applying these extraction mixtures, the values both of aflatoxin B₁ and of other aflatoxins were generally higher compared to those obtained by acetone–water 85 + 15; moreover, acetone–water (6 + 4) and (7 + 3) showed the best extraction efficiency for all aflatoxins.     

Nutritional and technological quality of bread enriched with an intermediated pearled wheat fraction

A strategy to maximise the health benefits of wheat-based products enriched with refined flour and selected fractions of kernel, obtained by sequential pearling, has been tested. Five mixtures of refined commercial flour with an increasing replacement of a pearled wheat fraction were used to prepare bread and were compared with a control for the dough rheological properties (Mixolab® parameters), the bioactive compound content, deoxynivalenol (DON) contamination and the physical properties (volume, crust colour, instrumental crunchiness and crumb texture profile analysis parameters). The antioxidant and dietary fibre contents increased linearly as the flour was enriched with the pearled fraction. The dietary fibre, β-glucan, total phenolic, alkylresorcinol content and the antioxidant activity increased significantly at a replacement level of 10%, while the technological properties were not significantly different from those of the control. It has been shown that refined flour could be enriched through the addition of a selected wheat pearled fraction and the bioactive compound content of composite bread could be improved, while few rheological and technological differences could be obtained and the risk for DON contamination could be limited.     

Vaginal Lactobacilli and Vaginal Dysbiosis-Associated Bacteria Differently Affect Cervical Epithelial and Immune Homeostasis and Anti-Viral Defenses

Persistent infection with High Risk-Human Papilloma Viruses (HR-HPVs) is a primary cause of cervical cancer worldwide. Vaginal-dysbiosis-associated bacteria were correlated with the persistence of HR-HPVs infection and with increased cancer risk. We obtained strains of the most represented bacterial species in vaginal microbiota and evaluated their effects on the survival of cervical epithelial cells and immune homeostasis. The contribution of each species to supporting the antiviral response was also studied. Epithelial cell viability was affected by culture supernatants of most vaginal-dysbiosis bacteria, whereas Lactobacillus gasseri or Lactobacillus jensenii resulted in the best stimulus to induce interferon-γ (IFN-γ) production by human mononuclear cells from peripheral blood (PBMCs). Although vaginal-dysbiosis-associated bacteria induced the IFN-γ production, they were also optimal stimuli to interleukin-17 (IL-17) production. A positive correlation between IL-17 and IFN-γ secretion was observed in cultures of PBMCs with all vaginal-dysbiosis-associated bacteria suggesting that the adaptive immune response induced by these strains is not dominated by T_H1 differentiation with reduced availability of IFN-γ, cytokine most effective in supporting virus clearance. Based on these results, we suggest that a vaginal microbiota dominated by lactobacilli, especially by L. gasseri or L. jensenii, may be able to assist immune cells with clearing HPV infection, bypasses the viral escape and restores immune homeostasis.     

Aspects of social reputation and peer relationships in Italian children: A cross-cultural perspective.

A group of Italian children (790 boys and 717 girls), 10–13 years old, were administered the Revised Class Play (Masten, Morison, & Pellegrini, 1985) in order to explore cross-cultural differences in social reputation with respect to North American studies. Children also were given sociometric nominations to examine the association between social reputation and peer acceptance–rejection. Exploratory and confirmatory factor analyses showed a 4-factor structure with the original Leadership-Sociability factor split in 2 separate dimensions: leadership and sociability. Leadership items seemed to draw a profile of a well-behaved, polite, and socially correct child, whereas Sociability items seemed to draw a profile of a child that is sociable, liked, exuberant, and ready to make friends and to interact with others. Moreover, the data suggested somewhat subtle forms of association between Aggression and Sociability. Results on relations between peer acceptance–rejection and social reputation confirmed North American findings. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A unified set‐theoretic approach to the analysis of PWL resistive circuits and composite N‐ports

We consider the search for all DC solutions of resistive piecewise‐linear (PWL) circuits and the analysis of the characteristics of resistive PWL composite N‐ports. These problems are unified from a theoretical and operating point of view by introducing the so‐called N‐augmented circuit, obtained from the N‐port by closing its ports with N norators. Set‐theoretic approach is used to describe the properties of the N‐augmented circuits leading to the formulation of a general DC analysis algorithm, based on linear programming techniques. The examples at the end of the paper show some practical and efficient application of the general DC analysis algorithm. Copyright © 2010 John Wiley & Sons, Ltd.     

Hidden Fumonisins: Simple and Innovative Extractions for Their Determination in Maize and Derived Products

Fumonisins B (FBs) can occur in maize as free forms and as hidden FBs (interaction between FBs and matrix macro-constituents). The analytical methods to detect free FBs in maize and derived products usually involve extraction with aqueous methanol and/or acetonitrile; for hidden FBs, alkaline hydrolysis (2 M KOH) and following CH₃CN extraction is used. Recently, we proposed a simple phosphate buffer (PB) extraction to detect free FBs in masa and maize samples. This study aimed at evaluating if this method is suitable to detect also hidden FBs; then, a comparison between the most common solvents, PB, and alkaline hydrolysis was carried out. For maize samples, the results showed that 0.4 M PB can extract both free and most hidden FBs; however, this method was not suitable for some categories of maize-based processed food products, in particular cornflakes, chips, and crispbreads. To solve this drawback, a modified PB extraction, which entails the addition of Carrez solutions in order to precipitate proteins, was tested and satisfactory results were obtained. Finally, the alkaline hydrolysis of maize-based food extracts showed that bound FBs can be co-extracted together with free forms by 0.4 M PB and quantified as hydrolyzed FBs.