Spectral nephelometry for making extravirgin olive oil fingerprints

In spectral nephelometry, absorption spectroscopy and nephelometry are innovatively combined to provide simultaneous online monitoring of color and turbidity of edible oils. Spectral nephelometry instrumentation consists of an optoelectronic device that measures the absorption spectrum of the oil sample at different angles. Data processing, carried out by principal component analysis (PCA), allows identification of the oil sample and creates a two-dimensional map as a fingerprint of oil types.     

A note on optimal metering schemes

A metering scheme is a method by which an audit agency is able to measure the interaction between servers (e.g., web servers) and clients (e.g., browsers) during a certain number of time frames. Metering schemes involve distributing information to clients and servers. Obviously, such information distribution affects the overall communication complexity. A metering scheme is said to be optimal if the information distributed to clients and servers is the minimum possible.Optimal metering schemes have been proposed by Naor and Pinkas [Lecture Notes in Comput. Sci., Vol. 1403, pp. 576-590] and Masucci and Stinson [Lecture Notes in Comput. Sci., Vol. 1895, pp. 72-87). In this paper we show a construction for optimal metering schemes, called the vector space construction, that generalizes previous constructions for optimal metering schemes.     

Secure E-Coupons

As the Internet is getting easier and faster to use, electronic coupon (e-coupon) distribution is becoming a more and more popular advertising technique. E-coupons are the digital analogue of paper coupons which are used to provide customers with discounts or gift in order to incentive the purchase of some products. Nowadays, the potential of digital coupons has not been fully exploited on the web. This is mostly due to the lack of efficient techniques to handle the generation and distribution of e-coupons. In this paper we discuss models and protocols for e-coupons satisfying a number of security requirements. Furthermore we present a lightweight implementation of our protocol, which preserves the privacy of the users, since it does not require any registration phase.     

A spectrophotometric method for the determination of hydroperoxides in liposomes

A modification of the Asakawa-Matsushita iodometric assay method for the determination of the content of lipid hydroperoxides was developed which permits the simultaneous processing of many samples of high lipid content. The method has the advantages of simplicity as well as good reproducibility, so it is not necessary to process standards with each determination. Our technique exceeds the sensitivity attained with other spectrophotometric determinations reported in the literature. The method requires the total elimination of water from the samples, and this was accomplished using an azeotropic mixture of ethanol:water of 96:4. The results obtained with liposomes indicate that the method is applicable to biological material limited to small volume samples, ranging 5-50 microliters. We want to emphasize that this method permits the study of the peroxidation process as function of time.     

A software infrastructure for authenticated Web metering

As the popularity of the Internet and the number of resources available on it have grown, potential customers are increasingly turning to it for information about products and services. Accordingly, online advertising is gaining a significant portion of the advertising market. The Internet has become a mainstream advertising channel, surpassing traditional media such as newspapers and radio in number of advertisements. Advertisers exploit the popularity of the best-known Web sites, typically search engines or portals, to advertise their products and reach the most potential customers. Traditional rating systems are of little value when applied to the Internet because of the enormous number of Web pages available to online advertisements. Counting accesses to a Web service is a difficult task and the data may be unreliable. Several metering techniques attempt to accurately measure the number of visits a site receives and hence the advertising exposure, but advertisers and auditing companies haven't adopted a standard technique. We propose a framework based on hash chains. Unlike similar approaches, our implementation minimizes the overhead associated with the additional communication required to implement the protocol while providing an efficient and flexible scheme. Furthermore, the resulting framework offers additional guarantees such as security and nonrepudiation of the produced proof of visits.     

Characterization of Violetto di Toscana,a typical Italian variety of artichoke (Cynara scolymus L.)

This work regards the characterization of the phenolic compounds and the mineral composition of the variety Violetto di Toscana, which is typically cultivated in Tuscany for the flavour of its edible part. All the results achieved are compared with those of var. Terom, which is widely used in Italy. A systematic study was performed on the different plant parts: the edible head and leaves, outer bracts and stems. The data for the whole plant showed that the polyphenol content of var. Violetto exceeds that of var. Terom by about 25%, so this variety could be regarded as a functional food and also as an interesting source of antioxidant phenolic compounds. A decoction of bracts and leaves was also carried out in order to evaluate the amount of polyphenols which may be extracted by a simple hot water extraction.     

Lipid reserve dynamics and magnification of persistent organic pollutants in spawning sockeye salmon (Oncorhynchus nerka) from the Fraser River, British Columbia

Pacific sockeye salmon (Oncorhynchus nerka) can travel several hundred kilometers to reach native spawning grounds and fulfill semelparous reproduction. The dramatic changes in lipid reserves during upstream migration can greatly affect internal toxicokinetics of persistent organic pollutants (POPs) such as PCBs, PCDDs, and PCDFs. We measured lipid content changes and contaminant concentrations in tissues (liver, muscle, roe/gonads) and biomarker responses (ethoxyresorufin O-deethylase or EROD activity and CYP1A levels) in two Pacific sockeye salmon stocks sampled at several locations along their spawning migration in the Fraser River, British Columbia. Muscle lipid contents declined significantly with increasing upstream migration distance and corresponded to elevated lipid normalized concentrations of PCBs and PCDD/Fs in spawning sockeye. Post-migration magnification factors (MFs) in spawning sockeye ranged between 3 and 12 and were comparable to model-predicted MFs. sigmaPCBs(150-500 ng x g(-1) lipid), sigmaPCDD/Fs (1-1000 pg x g(-1) lipid) and 2,3,7,8-TCDD toxic equivalent or TEQ levels (0.1-15 pg x g(-1) lipid) in spawning sockeye were relatively low and did not affect hepatic EROD activity/CYP1A induction. Despite a 3-fold magnification, TEQ levels in eggs of spawning Fraser River sockeye did not exceed 0.3 pg x g(-1) wet wt, a threshold level associated with 30% egg mortality in salmonids. PCBs in Fraser River sockeye are comparable to previous levels in Pacific sockeye. In contrast to Pacific sockeye from more remote coastal locations, PCDDs and PCDFs in Fraser River sockeye were generally minor components (<25%) of TEQ levels, compared to dioxin like PCB contributions (>75%). The data suggest that (i) the Fraser River is not a major contamination source of PCBs or PCDD/Fs and (ii) marine contaminant distribution, food-chain dynamics, and ocean-migration pathway are likely important factors controlling levels and patterns of POPs in returning Pacific sockeye. We estimate an annual chemical flux entering the Fraser River of up to 150 g for sigmaPCBs and 40 mg for sigmaPCDD/ Fs via returning sockeye. The results indicate that historical concentrations of PCBs and PCDD/Fs remain a potential threat to organism and ecosystem health on the west coast of Canada.     

Ideal contrast visual cryptography schemes with reversing

A visual cryptography scheme (VCS) for a set of n participants is a method to encode a secret image, consisting of black and white pixels, into n transparencies, one for each participant. Certain qualified subsets of participants can “visually” recover the secret image by stacking their transparencies, whereas, other, forbidden, subsets of participants, cannot gain any information about the secret image.Recently, Viet and Kurosawa proposed a VCS with reversing, which is a VCS where the participants are also allowed to reverse their transparencies, i.e., to change black pixels to white pixels and vice-versa. They showed how to construct VCSs with reversing where the reconstruction of black (white, respectively) pixels is perfect, whereas, the reconstruction of white (black, respectively) pixels is almost perfect. In both their schemes there is a loss of resolution, since the number of pixels in the reconstructed image is greater than that in the original secret image.In this paper we show how to construct VCSs with reversing where reconstruction of both black and white pixels is perfect. In our schemes each participant is required to store a certain number of transparencies, each having the same number of pixels as the original secret image. Moreover, our schemes guarantee no loss of resolution, since the reconstructed image is exactly the same as the original secret image. Finally, compared to the schemes of Viet and Kurosawa, our schemes require each participant to store a smaller amount of information.