Comparative study of commercially available cocoa products in terms of their bioactive composition

Recent trends in food marketing suggest that cocoa products, besides being favourite sweets among consumers, also present multiple-benefit foodstuffs, which are becoming objects of increased scientific research, mainly because of their interesting phytochemical composition. UV/VIS spectrophotometric and high-performance liquid chromatography (HPLC-PDA) methods were applied in order to compare the composition of polyphenols and methylxanthines in commercial cocoa products affected by different extraction solvents. Antioxidant capacity of water and methanol extracts was evaluated using DPPH (2,2-diphenyl-1-picrylhydrazyl), ABTS (2,2-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) and FRAP (ferric reducing/antioxidant power) assays. The obtained results confirmed that the content of polyphenols and methylxanthines, as well as the antioxidant capacity of cocoa products depend on the content of their cocoa solids. Among the tested cocoa products, the highest content of bioactive compounds (polyphenols and methylxanthines) was determined in extracts of cocoa products with the highest content of cocoa solids (cocoa liquor, cocoa powder and dark chocolate with 88% cocoa solids), while the lowest content was determined in milk chocolate and cocoa bar extracts. The most abundant phenolic compound in cocoa extracts was (?)-epicatechin, while the most abundant methylxanthine was theobromine. In comparison with water, 70% methanol demonstrated higher efficiency for the extraction of the studied bioactive compounds from cocoa products.     

Silver halide sensitized gelatin derived from BB-640 holographic emulsion

Silver halide sensitized gelatin (SHSG) is one of the most interesting techniques for the production of holographic optical elements, achieving relatively high sensitivity of photographic material with a low scattering of dichromated gelatin. Here we present experimental results for SHSG derived from the novel BB-640, a red-sensitive ultra-fine-grain emulsion from Holographic Recording Technologies (Steinau, Germany). The material is characterized before recording and after processing, and information about the thickness, absorption, and refractive-index modulation of the final holograms is obtained. The influence of the developer is analyzed, and diffraction efficiencies as great as 96.2% (after allowing for reflections) with a transmission of 1% and absorption and scatter losses of 2.8% are obtained with AAC developer. Our investigations reveal that high-quality SHSG transmission holograms may be obtained with the new BB-640 plates.     

Dielectric and Piezoelectric Properties of (Na0.5Bi0.5)(Ti1–xMnx)O3 (x = 0–0.1) Modified Ceramics

Inorganic Materials - We have studied the crystal structure and dielectric and local piezoelectric properties of (Na0.5Bi0.5)(Ti1–xMnx)O3 (x = 0–0.1) modified sodium bismuth...     

Theoretical and experimental study of the bleaching of a dye in a film-polymerization process

The quantum efficiency and the molar-absorption coefficients of different phenothiazine dyes are obtained by means of fitting the experimental data of transmittance as a function of time. An analytical expression for the intensity transmitted in a photopolymerizable holographic material is obtained, and good agreement between theory and experience is also achieved. The analysis of these parameters is of fundamental quantities in the photochemical characterization of holographic recording materials.     

Holographic optical elements recorded on spherical surfaces with photopolymers

A method for recording of holograms on spherical substrates is presented. As recording material we used a photopolymer placed between two spherical glass plates that are concentric.     

An enzootic with pseudo-tumoral manifestations in Vipera lebetina in captivity

The authors report the clinical and epizootic evolution of an epizooty, characterized by pseudo-tumours, observed on some vipers (Vipera lebetina) maintained in captivity at the "institut Pasteur de Tunis". The disease was characterized by 2.3 cm size nodules, scattered under the skin or into splanchnic cavities. These ones, spherical and well capsuled, were formed by a mass of clear rounded cells (histiocytes or monocytes), the necrotic central area of which contained innumerable bacteria. Several reviewed works show that this appearance of chronic abcess is a common and univocal reaction to various pathogenic factors, such as bacteria and parasites. As to etiology, the authors have doubt about the pathological role of the germs which they have identified (Salmonella and other anterobacteria) because these latter belong to the normal microbial flora of snakes and are, in the present case, probably occasional infective agents only.     

A Methodological Approach for Object-Relational Database Design using UML

The most common way of designing databases is by means of a conceptual model, such as E/R, without taking into account other views of the system. New object-oriented design languages, such as UML (Unified Modelling Language), allow the whole system, including the database schema, to be modelled in a uniform way. Moreover, as UML is an extendable language, it allows for any necessary introduction of new stereotypes for specific applications. Proposals exist to extend UML with stereotypes for database design but, unfortunately, they are focused on relational databases. However, new applications require complex objects to be represented in complex relationships, object-relational databases being more appropriate for these requirements. The framework of this paper is an Object-Relational Database Design Methodology, which defines new UML stereotypes for Object-Relational Database Design and proposes some guidelines to translate a UML conceptual schema into an object-relational schema. The guidelines are based on the SQL:1999 object-relational model and on Oracle8i as a product example. Initial submission: 22 January 2002 / Revised submission: 10 June 2002 Published online: 7 January 2003 This paper is a revised and extended version of Extending UML for Object-Relational Database Design, presented in the UML’2001 conference [17].