Chemoresistive Gas Sensors for Sub-ppm Acetone Detection☆

New sensors for detecting acetone directly in the exhaled breath have been developed. Several metal oxide materials, ZnO in different nano-morphologies, WO3 pure and Zr-loaded and TixSn1-xO2 solid solutions, have been considered for comparing the functional properties of the corresponding thick films with respect to the target gas. ZnO nano-sheets and bipyramidal nano-aggregates exhibited the large responses towards acetone, however ZnO aggregates of nanocrystals, Zr-WO3 and TixSn1-xO2 showed better performances as regards the influence of humidity on the acetone response

Study of doubly strange systems using stored antiprotons

Bound nuclear systems with two units of strangeness are still poorly known despite their importance for many strong interaction phenomena. Stored antiprotons beams in the GeV range represent an unparalleled factory for various hyperon-antihyperon pairs. Their outstanding large production probability in antiproton collisions will open the floodgates for a series of new studies of systems which contain two or even more units of strangeness at the P‾ANDA experiment at FAIR. For the first time, high resolution γ-spectroscopy of doubly strange ΛΛ-hypernuclei will be performed, thus complementing measurements of ground state decays of ΛΛ-hypernuclei at J-PARC or possible decays of particle unstable hypernuclei in heavy ion reactions. High resolution spectroscopy of multistrange Ξ−-atoms will be feasible and even the production of Ω−-atoms will be within reach. The latter might open the door to the |S|=3 world in strangeness nuclear physics, by the study of the hadronic Ω−-nucleus interaction. For the first time it will be possible to study the behavior of Ξ‾+ in nuclear systems under well controlled conditions

(Ti, Sn) SOLID SOLUTIONS as functional materials for gas sensing

Metal-oxide semiconductors are widely used as functional materials for gas sensing because of their chemoresistive effect when interacting with ambient gases. For this work, nanosized TixSn1−xO2 have been synthesized at increasing Ti molar ratio (x = 0, 0.1, 0.2, 0.25, 0.3, 0.5, 0.7, 0.8, 0.9, 0.95, 1) and extensively investigated through a wide variety of characterizations. It turned out that the merging process of the two single oxides formed new compounds with improved gas responses compared to pure TiO2 and also to pure SnO2. Moreover, all investigated physico-chemical characteristics resulted tuneable through the titanium content in the solid solution. Each characterization carried out onto TixSn1−xO2 solid solutions made it possible to identify two classes of materials with SnO2-like or TiO2-like behaviours, the best CO response being on the intersection of the two species of materials. Moreover, a very interesting analysis on the generally accepted electrical transport model through polycrystalline semiconductors has been carried out. Indeed, the comparison with experimental evidences has highlighted a conduction mechanism not previously considered

Ostreid herpesvirus type 1 genomic diversity in wild populations of Pacific oyster Crassostrea gigas from Italian coasts

International audienceOstreid herpesvirus 1 (OsHV-1) is a significant pathogen affecting the young Pacific oyster Crassostrea gigas, worldwide. A new variant, OsHV-1 μVar, has been associated with recurrent mortality events in Europe since 2008. Epidemiological data collection is key for global risk assessment; however little is known about health status and genotypes present in European wild oyster beds. Most studies to date have involved only cultivated individuals during mortality events, and reported low genotype diversity. With this study, conducted along the Italian coasts, we investigated for the first time the presence of OsHV-1 in European natural oyster beds. Analysis of three genomic regions revealed the presence of at least nine different genotypes, including two variants close to the OsHV-1 reference, known since the early 1990s but with no European record reported since 2010, and highlights relevant genotype diversity in natural environment. Phylogenetic analysis distinguished two distinct clusters and geographical distribution of genotypes, with the exception of a variant very closely related to the μVar, which appeared the single genotype present in all the Adriatic sites. Interestingly, these wild symptom free populations could represent, in Europe, an accessible alternative to the import of OsHV-1-resistant oyster strains from the East Pacific, the native area of C. gigas, avoiding the high-risk of non-native marine species and new pathogen introductions