Temperature and storage effects on antioxidant activity of juice from red and white grapes

The effect of temperature and storage time on the phenolic composition and on the antioxidant activity of grape (Vitis vinifera L.) juices made using a red (Sangiovese, SG) and a white (Muscat of Alexandria, MA) variety was studied. Total phenolics, flavonoids, flavan‐3‐ols and hydroxycinnamoyl‐tartrates (HCT) were determined on grape extracts (GE) and juices. Total anthocyanins and anthocyanins composition were measured on GE. The antioxidant activity was assessed by means of two different in vitro tests: scavenging of the stable 2,2‐diphenyl‐1‐picrylhydrazyl radical and the inhibition of tyrosine nitration mediated by authentic peroxynitrite (ONOO^?). All the juices were analysed after 24 h and 2 weeks of storage by means of two‐way anova (factors being cultivar and temperature). Anthocyanins were not detected in MA extract, whereas in SG their content was 534 mg malvidin‐equivalent per 100 g of dry matter (d.m.) and malvidin derivatives (glycosylated and coumaroylated) were the most represented (respectively 169 and 41 malvidin‐equivalent per 100 g of d.m.). HCT content of the extracts was higher in SG (overall +33%). Also in grape juices, HCT were lower in MA and in this variety, the trans‐fertaric and cis‐coutaric acids were also undetectable. Cultivar effect proved to be highly significant, while no significant differences in the phenolic composition were observed for storage temperatures (4 and ?20 °C) and cultivar × temperature interaction. However, when statistical analysis was focused on each cultivar, MA was found to be more sensible to storage conditions and a significant reduction in total phenolics (?20%) and flavonoids (?53%) content and in the ONOO^? scavenging potential (?32%) was evident after 2 weeks at 4 °C (when compared with the same storage temperature after 24 h). On the contrary, SG juices did not show significant differences among the four storage treatments investigated. These results could be explained suggesting that anthocyanins presence in red grape plays a key role in juice stability.     

Pavement Life-Cycle Cost and Asphalt Binder Quality: Theoretical and Experimental Investigation

Quality control/quality assurance tests can be used to demonstrate that an as-constructed pavement has characteristics different from the contracted specifications of the as-designed pavement because the bitumen employed was of insufficient quality. Many different issues affect asphalt binder quality. Such problems can significantly increase the pavement life-cycle cost, which means that a pay adjustment (PA) is needed. Unfortunately, the quantitative analysis of this issue is very complex. The objectives of this study were to model the dependence of the pavement life-cycle cost on asphalt binder quality and to determine the quantitative relationship between bitumen viscosity and the PA for a given class of boundary conditions. In addition to modeling this problem theoretically, experiments and simulations were carried out through the use of the Mechanistic-Empirical Pavement Design Guide. We then derived the consequences of these effects on life-cycle cost by using a specific life-cycle cost model. Our results demonstrate that asphalt binder viscosity can strongly affect the expected pavement life and the PA, and thus needs to be taken into account in contract and construction management.     

A voltage controlled CMOS current divider with linear characteristic

A compact voltage controlled CMOS current divider is presented. Differently from previous implementations, exploiting the MOSFET translinear characteristics in subthreshold region, the proposed circuit is based on devices operating from moderate to strong inversion. An input current linearity range of nearly a decade is obtained by compensating for the deviations from the ideal drain current square-law approximation through an original empirical approach. The circuit is suitable for use as a building block in analog multipliers and for transconductor continuous tuning. The effectiveness of the proposed configuration is demonstrated by means of electrical simulations, performed on a prototype designed with a commercial process. The robustness of the linearization algorithm with respect to temperature variations is proven.     

Alloying Behaviour of Zinc with Rare Earth Metals: The Er-Pr-Zn System

Zinc based alloys are among the most commonly used light alloys. To improve the knowledge of the ternary systems constituted by zinc with two lanthanides the isothermal section at 400 °C of the Er-Pr-Zn system was studied. Some selected samples at the Er:Pr ratio?=?1:1 were investigated by differential thermal analysis to draw the vertical section of the system. The experimental techniques used were x-ray powder diffraction, scanning electron microscopy, coupled with electron probe microanalysis and differential thermal analysis. No ternary compounds were found in the system. As regard the intermetallic phases, the (Er, Pr)Zn (Er, Pr)Zn₂, (Er, Pr)Zn_3, (Er, Pr)₁₃Zn₅₈ and (Er, Pr)₂Zn₁₇ solid solutions form in the full field of composition, while the ErZn₁₂, Pr₃Zn₁₁ and PrZn₁₁ compounds partially dissolve the third element. The metastable intermetallic binary phases ErZn₅, PrZn₅ and Er₆Zn₂₃ were not found either as ternary solid solutions or as binary compounds in the ternary Er-Pr-Zn system at 400 °C.     

A Novel Function of the Triterpene Squalene in a Tritrophic System

Changes in apple leaf chemistry after infestation by leafminers and their effect on both host location and host habitat location of the generalist parasitoid Pholetesor bicolor were investigated. Chemical analysis of leaf solvent extracts from healthy and leafminer-damaged leaves revealed that herbivory increased the amount of the triterpene squalene (C₃₀H₅₀), whereas quantities of all other identified compounds were similar in both plant treatments. To assess the response of parasitoids to host location cues, contact bioassays were conducted with naïve females. Results showed that parasitoids performed a characteristic ovipositional probing more often on the mine-damaged than on the healthy leaf. This behavior was triggered by a hexane extract of the mine-damaged leaf, but not by a healthy leaf extract. A synthetic mixture of the compounds identified in the extract triggered a similar response. A mixture devoid of squalene was not active, whereas squalene alone elicited the probing behavior. To assess the use of the identified compounds in habitat location, Y-tube olfactometer experiments were conducted with naïve and experienced females. Results showed that squalene is not involved in habitat location and has no priming effect on P. bicolor. While other triterpenes are known to mediate habitat location of parasitoids, this is the first report in which a plant triterpene is shown to mediate host location of a parasitoid. The biological and ecological functions of squalene on all three trophic levels are discussed.     

UHMWPE oxidation increases matrix metalloproteinase-2 (MMP-2) release in human fibroblast

MRC-5 human fibroblast were grown polystyrene plates, UHMWPE slices and UHMWPE slices oxidized in air in oven at 120 °C for 80 h. Cell proliferation and cytotoxicity were assessed after 24, 48, and 72 h. Control cells grown on polystyrene doubled their number after 72 h while both cell population grown on UHMWPE and oxidized UHMWPE showed a reduced proliferation rate. Both UHMWPE types seem to induce a cytostatic rather than a cytotoxic effect, in fact, no difference in the LDH release were observed between the three cell populations at 24, 48, and 72 h. Gelatinase activity was assessed in cell medium at every time point using gelatin zymography. Only gelatinase B (MMP-2) activity was present in MRC-5 conditioned medium. Oxidized UHMWPE induced a strong release of MMP-2 after 72 h compared to control and UHMWPE samples. The augmented MMP-2 release in the absence of a cytotoxic phenomenon suggests a possible role for UHMWPE oxidation in the MMPs stimulation observed in the periprosthetic tissues.     

Design of CMOS checkers with improved testability of bridging and transistor stuck-on faults

This work presents a design technique for CMOS static and dynamic checkers (to be used in self-checking circuits), that allows the detection of all internal single transistor stuck-on and bridging faults causing unacceptable degradations of the circuit dynamic performance (but not logical errors). Such a technique exploits simple voltage detector circuits to make sure that the intermediate faulty voltages inevitably produced by the faults of interest are always propagated at the checker output as logic errors.With the use of our technique, the main disadvantages of static checkers, so far preventing their use in practical applications, are overcome.The method has been applied to the particular case of two-rail (static as well as dynamic) checkers and its validity has been verified by means of electrical level simulations.     

Influence of annealing on the phase composition,transmission and resistivity of SnOx thin films

Undoped and antimony-doped tin oxide films were prepared by d.c. reactive ion sputtering in an argon atmosphere with oxygen partial pressures ranging from 0 to 50%. The films were annealed in air, nitrogen and a vacuum in the temperature range 570–750 K. The influence of thermal annealing on the structural properties, electrical resistance and optical transmittance is described.