Microbial ecology of artisanal products from North West of Italy and antimicrobial activity of the autochthonous populations

A total of about 1000 autochthonous strains were isolated from fresh and fermented artisanal products (cheese and meat) of the Piedmont area (Northwest of Italy) and screened for their antimicrobial activity. Among them, 98 bacteriocin-producing strains were detected and identified by molecular methods and genetic determinants encoding the antimicrobial proteins were targeted by PCR. The bacteriocins produced by isolates showed antimicrobial activity towards different spoilage and pathogenic microorganisms such as Listeria monocytogenes, Staphylococcus aureus, Clostridium tyrobutyricum and Brochothrix thermosphacta. Identification of the bacteriocin producing strains resulted in a large number of Lactococcus and Enterococcus strains with a broad spectrum of activity towards more that one spoilage and/or pathogenic microorganisms tested. In several strains it was possible to detect a combination of different genes responsible for the bacteriocin activity. These newly isolated bacteriocin-producing strains represent potential starters or co-starters to be used in food stabilization using the approach of the biopreservation.     

A Design Methodology for MOS Current-Mode Logic Frequency Dividers

In this work, a methodology for the design of MOS current-mode logic frequency dividers is presented. A mix of hand calculations and circuit simulations is used to relate the power consumption and the frequency of operation. Each latch in the dividers is sized separately in order to minimize the overall power consumption. Furthermore, the effect on the power consumption of circuit parameters such as output swing and voltage gain of the input differential pair is analyzed in detail. The methodology has been applied to dividers by two and dividers by three with 50% output duty cycle     

Physico‐mechanical evaluation of the aptitude of berries of red wine grape varieties to resist the compression in carbonic maceration vinification

By texture analysis tests, the ability of berries to resist rupture under compression load during intracellular fermentation was studied for twenty‐three red wine grape varieties. The softest berries were associated with Ancellotta (1.72 N), Dolcetto (1.79 N), Gamay (2.26 N) and Schiava gentile (2.29 N) cultivars. The hardest berries corresponded to Franconia and Bonarda cultivars (4.02–4.03 N). High resistance to splitting was also detected for Grenache, Raboso, Marzemino, Negramaro, Montepulciano and Croatina cultivars (3.50–3.95 N). The differentiating power of the mechanical variables of the whole berry and skin was assessed by univariate and multivariate analysis. Relationships among the instrumental berry hardness and other physical and mechanical properties were also investigated. The results obtained suggest that the manufacture of carbonic macerated wines should be planned considering the berry hardness, and it represents a new variable that should be considered in selecting the most appropriate wine grape variety to elaborate these wines.     

Effect of the cluster heterogeneity on mechanical properties,chromatic indices and chemical composition of Italia table grape berries (Vitis vinifera L.) sorted by flotation

The impact of cluster heterogeneity on mechanical properties, chromatic indices and chemical composition of Italia table grape berries sorted by flotation was evaluated in this study. The density sorting at commercial harvest permitted to get berries of different ripeness and relatively different quality attributes. Individually, some grape chromatic characteristics, physical characteristics (weight of the whole berry and berry skin), content and composition of reducing sugars, organic acids and phenolic compounds (flavanols of low molecular mass in berry skins) permitted to characterise and to differentiate berries belonging to different density classes. However, the tested mechanical properties were not related to the berry density. When the variables that significantly contributed to the berry differentiation were globally assessed, the chemical parameters related to sugars (142.3–164.4 g kg^?1), content of skin oligomeric flavanols [46.3–137 mg (+)‐catechin kg^?1], berry skin weight (379–607 mg), yellow/blue colour component (26.31–29.96) and chroma (26.40–30.06) were the more representative.     

Nanoscale Cu supported catalysts in the partial oxidation of cyclohexane with molecular oxygen

Cu supported catalysts (support: γ-Al₂O₃, Fe₂O₃, TiO₂) have been conveniently prepared by deposition of Cu particles from acetone solvated Cu atoms. The catalysts have been characterized by HRTEM analysis, showing a quite homogeneous Cu particle size distribution. They are active systems for the partial oxidation of cyclohexane to cyclohexanol and cyclohexanone. After the catalytic experiment the Cu/γ-Al₂O₃ and Cu/TiO₂ systems can be reused without valuable loss of activity, while the Cu/Fe₂O₃ system is quite inactive.     

Tungsten Trioxide Films with Controlled Morphology and Strong Photocatalytic Activity via a Simple Sol–Gel Route

Novel nanostructured tungsten trioxide (WO₃) films with strong photocatalytic activity, have been prepared by a simple sol–gel route from aqueous peroxopolytungstic acid (PTA) precursor solutions. We demonstrate that films with different morphologies can be synthesized by simply adjusting the pH of this precursor solution using different mineral acids such as HCl and HC1O₄, and that this control of film texture represents a way of optimizing photocurrent yield. The best films produced using these methods generated anodic photocurrents of 3.8 mA/cm² for oxidiation of methanol and 2.2 mA/cm ² for water splitting, under AM1.5 simulated solar illumination.     

Corrosion behaviour of steel in concrete in the presence of stray current

Effects of stray current on the corrosion behaviour of steel in concrete have been studied, with regards to both corrosion initiation and propagation. Results showed that DC current can induce corrosion initiation on the reinforcement in the anodic zone only after it has circulated for a certain time, which depends on the anodic current density, the presence of chloride in the concrete and interruptions in the current. AC current proved to be much less dangerous than DC, although it can influence the corrosion rate of steel in chloride-contaminated concrete and stimulate macrocouples.