Contextualizing ontologies

Ontologies are shared models of a domain that encode a view which is common to a set of different parties. Contexts are local models that encode a party’s subjective view of a domain. In this paper, we show how ontologies can be contextualized, thus acquiring certain useful properties that a pure shared approach cannot provide. We say that an ontology is contextualized or, also, that it is a contextual ontology, when its contents are kept local, and therefore not shared with other ontologies, and mapped with the contents of other ontologies via explicit (context) mappings. The result is Context OWL (C-OWL), a language whose syntax and semantics have been obtained by extending the OWL syntax and semantics to allow for the representation of contextual ontologies.     

Hydrogen production from methanol by oxidative steam reforming carried out in a membrane reactor

The aim of this work is to study from an experimental point of view the oxidative steam reforming of methanol by investigating the behaviour of a dense Pd/Ag membrane reactor (MR) in terms of methanol conversion as well as hydrogen production. The main parameters considered are the operating temperature and the O₂/CH₃OH feed ratio. This is a pioneer work in the application of MR to this kind of reaction, whose goal should be to produce a CO-free hydrogen stream suitable for hydrogen fuel cell applications. The experimental results show that the MR gives methanol conversions higher than traditional reactors (TRs) at each temperature investigated, confirming the good potential of the membrane reactor device for this interesting reaction system.     

Characterization of Mediterranean mussels (Mytilus galloprovincialis) harvested in Adriatic Sea (Italy)

The aim of this work was to analyse some quality parameters of Mytilus galloprovicialis harvested monthly in the period ranging from April 2002 and February 2003 in a longline off-shore mussel farm, located in the Adriatic Sea, near Cattolica (Emilia Romagna Region, Italy). After harvesting, the samples were analysed in order to determine the counts of fecal coliforms (FC) and Escherichia coli, the presence of Salmonella, as prescribed by Italian and European Community regulations, and other pathogens (Vibrio parahaemolyticus, Listeria monocytogenes), as well as the meat yield and its proximate composition, its Fe, Cr, Cd, Zn, Pb and Cu content, the total lipids of the meat and their specific composition. The results obtained evidenced that many of the parameters studied, i.e. the meat proximate composition, the lipid fatty acid composition and the microbiological indices, were subjected to seasonal fluctuations. In particular, the microbiological data showed that 4 mussel samples (June, December, January and February) out of 12 did not match the limit imposed by Italian law and Emilia Romagna protocol concerning the FC and E. coli counts. While L. monocytogenes and Salmonella spp. were never detected in all the samples analysed, three samples (April, January and February) were positive for the presence of V. parahaemolyticus. No seasonal fluctuations were evidenced for Fe, Cr, Cd, Zn, Pb and Cu contents, always under the limits imposed by Italian law.     

Digital library information-technology infrastructures

This paper charts a research agenda on systems-oriented issues in digital libraries. It focuses on the most central and generic system issues, including system architecture, user-level functionality, and the overall operational environment. With respect to user-level functionality, in particular, it abstracts the overall information lifecycle in digital libraries to five major stages and identifies key research problems that require solution in each stage. Finally, it recommends an explicit set of activities that would help achieve the research goals outlined and identifies several dimensions along which progress of the digital library field can be evaluated.     

A mediator-based approach for integrating heterogeneous multimedia sources

In many applications, the information required by the user cannot be found in just one source, but has to be retrieved from many varying sources. This is true not only of formatted data in database management systems, but also of textual documents and multimedia data, such as images and videos. We propose a mediator system that provides the end-user with a single query interface to an integrated view of multiple heterogeneous data sources. We exploit the capabilities of the MOMIS integration system and the MILOS multimedia data management system. Each multimedia source is managed by an instance of MILOS, in which a collection of multimedia records is made accessible by means of similarity searches employing the query-by-example paradigm. MOMIS provides an integrated virtual view of the underlying multimedia sources, thus offering unified multimedia access services. Two features are that MILOS is flexible—it is not tied to any particular similarity function—and the MOMIS’s mediator query processor only exploits the ranks of the local answers.     

A survey of antibiotic resistance in Micrococcaceae isolated from Italian dry fermented sausages

The transfer of bacteria that are resistant to antimicrobial agents or resistance genes from animals to humans via the food chain is increasingly a problem. Therefore, it is important to determine the species and the numbers of bacteria involved in this phenomenon. For this purpose, 148 strains of microstaphylococci were isolated from three types of Italian dry fermented sausages. Eight of 148 strains belonged to the genera Kocuria and Micrococcus. The remaining 140 strains belonged to 11 different species of the genus Staphylococcus. The species most frequently isolated was Staphylococcus xylosus, followed by Staphylococcus saprophyticus and Staphylococcus aureus. Antibiotic resistance levels differed among the species and depended on the strain origin. Microstaphylococci were generally susceptible to beta-lactams, but 12 strains were resistant to methicillin, 8 were resistant to oxacillin, and 9 were resistant to penicillin G. No resistance was observed for aminoglicosides and cephalosporines. Many strains were resistant to sulfonamide, colistin suphate, tetracyclin, and bacitracin. Two strains of S. aureus, four strains of S. xylosus, and one strain of Staphylococcus sciuri were able to grow in the presence of 8 microg of vancomycin per g, but all strains were susceptible to teicoplanin. Twenty-two microstaphylococci were resistant to at least five of the tested antibiotics. The multiresistant strain S. aureus 899 was unaffected by eight antibiotics, including vancomycin and methicillin, indicating that a more prudent use of antibiotics in animal husbandry and better hygienic conditions during production should be encouraged because they can play a major role in reducing the incidence of such multiresistant microorganisms and the possible spread of the genetic elements of their resistance.     

A Curcumin-BODIPY Dyad and Its Silica Hybrid as NIR Bioimaging Probes

In this paper we describe the synthesis of a novel bichromophoric system in which an efficient photoinduced intercomponent energy transfer process is active. The dyad consists of one subunit of curcumin and one of BODIPY and is able to emit in the far-red region, offering a large Stokes shift, capable of limiting light scattering processes for applications in microscopy. The system has been encapsulated in MCM-41 nanoparticles with dimensions between 50 and 80 nm. Both the molecular dyad and individual subunits were tested with different cell lines to study their effective applicability in bioimaging. MCM-41 nanoparticles showed no reduction in cell viability, indicating their biocompatibility and bio-inertness and making them capable of delivering organic molecules even in aqueous-based formulations, avoiding the toxicity of organic solvents. Encapsulation in the porous silica structure directed the location of the bichromophoric system within cytoplasm, while the dyad alone stains the nucleus of the hFOB cell line.     

Effects of aw at packaging time and atmosphere composition on aroma profile,biogenic amine content and microbiological features of dry fermented sausages

The aim was to evaluate the effects of different water contents (corresponding to a_w 0.940, 0.914, 0.895 and 0.875) of sausages at different times on the characteristics of typical Italian dry fermented sausages packaged under two different modified atmospheres (MAP) (100%N₂ or 30%CO₂/70%N₂). During ripening and storage, samples were analyzed to evaluate pH and a_w changes, microbial population, biogenic amine (BA) accumulation and aroma profile.     

Methods for determination of degree of reaction of slag in blended cement pastes

To measure the degree of reaction of slag in blended pastes, five methods were studied. Selective dissolution and differential scanning calorimetry are shown to be unreliable, SEM-BSE-IA-mapping is time consuming, but does provide good results with a reasonable degree of precision. The difference in cumulative calorimetry and chemical shrinkage curves of slag blends in comparison to blends with inert filler shows potential to isolate the reaction of the slag. These methods have the advantage of being continuous, techniques with good precision, but the absolute heat of hydration, or contribution to chemical shrinkage of any particular slag is not known. Calibration of the calorimetry technique with SEM-BSE-IA-mapping seems to be a promising method to understand and quantify the degree of reaction of slag.     

Influence of self heating and Li2SO4 addition on the microstructural development of calcium aluminate cement

Hydrated Calcium Aluminate Cement (CAC) is known to have a complex microstructure involving different phase assemblages strongly dependant on the temperature. This work presents an experimental approach to study the microstructure of CAC pastes from the first minute of hydration with controlled time-temperature histories up to several months of curing. The self heating usually occurring in the CAC concrete is considered and its influence on the growth and assemblage of the hydration products and subsequent space filling is shown. Quantification of the degree of CA hydration by BSE image analysis is used to understand the evolution of phases throughout the hydration process. Lithium sulphate is commonly used to control the setting time of CAC based materials. It is shown that this promotes the formation of more stable hydrates, but slightly reduces the extent of CA hydration.