Bioaugmentation-Assisted Phytostabilisation of Abandoned Mine Sites in South West Sardinia.

Bioaugmentation-assisted phytoremediation implies the administration of selected plant growth promoting bacteria, which significantly improve plant growth and sequestration of heavy metals. In this work, 184 bacterial strains associated with roots of Pistacia lentiscus were isolated from plants spontaneously growing in the abandoned Sardinian mining areas (SW Sardinia, Italy) and phylogenetically characterised. Twenty-one bacterial isolates were assayed for properties relevant for plant growth promotion and metal tolerance. Five different strains, belonging to the genera Novosphingobium, Variovorax, Streptomyces, Amycolatopsis, Pseudomonas, were selected based on their properties for the greenhouse phytoremediation tests. Among the tested inocula, the strain Variovorax sp. RA128A, able to produce ACC deaminase and siderophore, was able to significantly enhance germination and increase length and weight of shoots and roots. Irrespective of the applied treatment, mastic shrub was able to accumulate Cd, Pb and Zn especially in roots.

The genetic diversity and spatial genetic structure of the Corso-Sardinian endemic Ferula arrigonii Bocchieri (Apiaceae).

Corsica and Sardinia represent major hotspots of plant diversity in the Mediterranean area and are priority regions for conservation due to their high number of endemic plant species. However, information supporting human decision-making on the conservation of these species is still scarce, especially at the genetic level. In this work, the first assessment is reported of the species-wide spatial genetic structure and diversity of Ferula arrigonii Bocchieri, a Corso-Sardinian endemic located in a few coastal sites and on small islands. Nine populations covering the entire natural range of the species were investigated by means of AFLP (amplified fragment length polymorphism) markers. Results indicate that this species is characterised by high levels of genetic polymorphism (92% polymorphic fragments) and of genetic diversity (H(w) = 0.317) and by relatively low differentiation among populations (F(st) = 0.057). PCoA, Bayesian analysis and neighbour-joining clustering were also employed to investigate the genetic structure of this species. Three genetically distinct groups were detected, although with considerable overlap between populations.

Molecular epidemiological investigation of an outbreak of Pseudomonas aeruginosa infection in an SCT unit.

From May to October 2006, six severe Pseudomonas aeruginosa infections were diagnosed in patients undergoing SCT in the SCT unit of the Careggi hospital (Florence, Italy). Four of the infected patients were treated consecutively in the same room (room N). On the hypothesis of a possible environmental source of infection, samples were collected from different sites that had potential for cross-contamination throughout the SCT unit, including the electrolytic chloroxidant disinfectant used for hand washing (Irgasan) and the disinfectant used for facilities cleaning. Four of the environmental samples were positive for P. aeruginosa: three Irgansan soap samples and a tap swab sample from the staff cleaning and dressing room. The AFLP (amplified fragment length polymorphism) typing method employed to evaluate strain clonality showed that the isolates from the patients who had shared the same room and an isolate from Irgasan soap had a significant molecular similarity (dice index higher than 0.93). After adequate control measures, no subsequent environmental sample proved positive for P. aeruginosa. These data strongly support the hypothesis of the clonal origin of the infective strains and suggest an environmental source of infection. The AFLP method was fast enough to allow a 'real-time' monitoring of the outbreak, permitting additional preventive measures.

In vivo and in vitro skin permeation of butyl methoxydibenzoylmethane from lipospheres.

Lipid microparticles (lipospheres) loaded with butyl methoxydibenzoylmethane (BMDBM), a widely used UV-A sunscreen agent, were prepared by melt technique and evaluated for skin permeation both in vivo, by tape stripping method, and in vitro, by a flow-through diffusion chamber. Following in vivo human skin application of an O/W emulsion containing 2% of BMDBM loaded in lipospheres, 15% of the applied sunscreen accumulated in the uppermost layers of the stratum corneum without remarkably modifying the skin permeation of the unencapsulated sunscreen. These results were found to be predicted by an in vitro methodology involving the diffusion of BMDBM through a lipophilized synthetic membrane into a hydrophilic receptor phase, simulating the viable epidermis better than an ethanolic receptor phase.

Conservation studies on ornamental and building stones of north-eastern Sicily. Hydric and colorimetric investigations.

In this paper we report on the results regarding the hydric properties of lithic materials widely used in north-eastern Sicily. We report also on the hydrophobic properties of these stones treated with some preserving products (silanes, siloxanes, epoxides, perfluoropolyethers, acrylates, acrylsilicones). In addition, the quantitative colour readings of the untreated and treated stones are presented, together with their chromatic alterations after artificial UV weathering. Final considerations on the selection of the best regime treatment are also reported.

Conservation studies on ornamental and building stones of north-eastern Sicily. Geomineralogical and porosimetric investigations.

The effectiveness, as preserving agents, of a series of chemical compounds (silanes, siloxanes, epoxides, perfluoropolyethers, acrylates, acrylsilicones) has been tested on lithic materials mainly used in artistic stoneworks of north-eastern Sicily. The selection and classification of the stone types, based on geomineralogical criteria follows a brief excursus about their use as artistic materials. The results of the porosimetric investigations, before and after conservation treatments, are reported. In addition, polarizing mineralogical microscope photos of the studied lithoid materials are presented.

Firing frequency of leaky intergrate-and-fire neurons with synaptic current dynamics.

We consider a model of an integrate-and-fire neuron with synaptic current dynamics, in which the synaptic time constant tau' is much smaller than the membrane time constant tau. We calculate analytically the firing frequency of such a neuron for inputs described by a random Gaussian process. We find that the first order correction to the frequency due to tau' is proportional to the square root of the ratio between these time constants radicaltau'/tau. This implies that the correction is important even when the synaptic time constant is small compared with that of the potential. The frequency of a neuron with tau'>0 can be reduced to that of the basic IF neuron (corresponding to tau'=1) using an "effective" threshold which has a linear dependence on radical tau'/tau. Numerical simulations show a very good agreement with the analytical result, and permit an extrapolation of the "effective" threshold to higher orders in radical tau'/tau. The obtained frequency agrees with simulation data for a wide range of parameters.