A novel approach to deliverable power in low‐voltage DC distribution system on the basis of voltage stability

This paper proposes that a deliverable power through a low‐voltage DC distribution system has an upper limitation. The upper limitation of the deliverable power, P_lim, is explained on the basis of a voltage instability phenomenon occurring for the load with a voltage sensitivity below 1. From theoretical‐calculation results, it is pointed out that P_lim diminishes with augment in the distribution‐line length. This phenomenon becomes more distinct for the higher distribution‐line inductance per unit length. Connection of the capacitor to the receiving end of the distribution line is discussed as a method for rising P_lim. Measurements of the voltage waveform at the load terminals successfully support P_lim derived from the theoretical calculation. © 2011 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

The occurrence and bioactivity of polyphenols in Tunisian olive products and by-products: a review

Polyphenols have become a subject of intense research because of their perceived beneficial effects on health due to their anticarcinogenic, antiatherogenic, anti-inflammatory, and antimicrobial activities. It is well known that olives and their derivatives are rich in phenolic substances with pharmaceutical properties, some of which exert important antioxidant effects. The characterization and quantification of their polyphenol composition is one of the first steps to be taken in any evaluation of the putative contribution of the olive to human health. This review is concerned with polyphenols in Tunisian olive (Olea europaea L.) products (fruit and oil) and some by-products (leaves and olive-mill wastewater) with an emphasis on the analytical methods used, as well as the biological activities described in recent years.     

Detection of Raw Pork Targeting Porcine-Specific Mitochondrial Cytochrome B Gene by Molecular Beacon Probe Real-Time Polymerase Chain Reaction

Pork identification in raw meat using real-time polymerase chain reaction (PCR) was developed. Total DNA from meat samples were successfully extracted and found to be of high quality and produced clear PCR products. Porcine-specific molecular beacon probe and primers that amplifies 119 bp of the cytochrome b gene fragment of swine (Sus scrofa domestica) was used. Analysis of data showed that the C _q (quantification cycle) from 10 ng/μl porcine DNA is (18.70 ± 0.12 to 19.08 ± 0.06). Meanwhile, the other samples exhibited negative result, which confirmed the specificity of the primers. The method also showed that the limit of detection of pork was 0.0001 ng. Based on the regression analysis of the standard curve, the 96% efficiency of real-time PCR was achieved with high correlation coefficient (r ² = 0.9989). Sensitivity of the assay in discriminating pork as low as 0.1% (w/w) pork in pork–beef mixtures was also obtained. Reproducibility of the assay was successfully validated by applying sample and experimental replicates in every assay being conducted. Thus, this methodology could serve as a fast and sensitive method for detection of pork for meat species verification.     

Microwave heating effects on the chemical composition and the antioxidant capacity of tataouine virgin olive oils from Tunisia

Four Tunisian virgin olive oils (VOOs), derived from varieties (Chemlali Tataouine, Zarrazi Douirat, Fakhari Douirat, and Dhokar Douirat) grown in the harsh pedoclimatic conditions of the region of Tataouine, were evaluated for their responses to microwave heating. Aside from fatty acid composition, all other evaluated parameters were affected by microwave heating, and their variations depend on the genetic factor. Chemlali Tataouine VOO exhibited the slowest biophenol degradation rate and the least diminution in oxidative stability and consequently, its total fraction and both lipidic and methanolic fractions remained unchanged with an exceptional antioxidant potential. In the remaining studied VOOs, the biophenol contents, the oxidative stability, and the antioxidant potential underwent gradual decreases; nevertheless, their levels at the longer treatment time are close to some fresh VOOs. These results should be taken into consideration when Tataouine VOOs are recommended for microwave heating.     

Effect of olive ripeness on chemical properties and phenolic composition of chétoui virgin olive oil

BACKGROUND: The aim of the present work was to investigate the influence of fruit ripening on oil quality in an attempt to establish an optimum harvesting time for Chétoui olives, the second main olive variety cultivated in Tunisia. RESULTS: Our results showed that many analytical parameters, i.e., peroxide value, UV absorbance at 232 and 270 nm, chlorophyll pigments, carotenoids and oleic acid contents decreased during ripening, whilst oil content and linolenic acid increased. Free acidity remained practically stable with a very slight rise at the highest maturity index. The trend of oxidative stability, total phenols and o‐diphenols, showed an increase at the early stages followed by a reduction at more advanced stages of maturity. The major phenolic compounds, such as hydroxytyrosol, ligstroside aglycon, elenolic acid, acetoxy‐pinoresinol and oleuropein aglycon, seemed to have the same behaviour. In the case of tyrosol, a strong decrease was observed directly related with the ripening progress. CONLUSION: On the basis of the evolution of the analytical parameters studied, the best stage of Chétoui olive fruits for oil processing seems to be at ripeness index higher than 2.0 and lower than 3.0. Copyright © 2009 Society of Chemical Industry     

Reactions of 4-Benzylidene-3-methyl-5-oxopyrazoline,pyrazole blue,and rubazoic acid with GRIGNARD reagents

While 4-benzylidene-3-methyl-5-oxopyrazoline 1 and pyrazole blue 2 with GRIGNARD reagents gave 1,4-addition, rubazoic acid 3 gave 1, 2-addition on both sides with ethylmagnesium bromide.