Pseudomonas aeruginosa is a highly adaptable bacterium that thrives in a broad range of ecological niches and can infect multiple hosts as diverse as plants, nematodes and mammals. In humans, it is an important opportunistic pathogen. This wide adaptability correlates with its broad genetic diversity. In this study, we used a deep-sequencing approach to explore the complement of small RNAs (sRNAs) in P. aeruginosa as the number of such regulatory molecules previously identified in this organism is relatively low, considering its genome size, phenotypic diversity and adaptability. We have performed a comparative analysis of PAO1 and PA14 strains which share the same host range but differ in virulence, PA14 being considerably more virulent in several model organisms. Altogether, we have identified more than 150 novel candidate sRNAs and validated a third of them by Northern blotting. Interestingly, a number of these novel sRNAs are strain-specific or showed strain-specific expression, strongly suggesting that they could be involved in determining specific phenotypic traits.

In the present work, laser ablation of a graphite target submerged in pure water was tested as a methodology for the production of carbon-based nanoparticles. The effect of varying the external pressure imposed to the liquid was investigated for the first time, in the range from 1 to 146 atm. Single or double laser pulses were used to ablate the target and the produced nanoparticles were characterized by atomic force microscopy (AFM) and by Raman spectroscopy. A spectroscopic study of the laser induced plasma features was carried out with a Ti target and interpreted in terms of laser-induced cavitation phenomena. Tubular nanoparticles of 25 nm average diameter were obtained only by single pulse (SP) ablation of graphite, while particles formed with the double pulse (DP) technique mainly consisted of graphite particulates. At 1 atm, these tubular nanoparticles were few and mixed with diamondlike carbon, while at 146 atm they were produced in a larger amount, suggesting that the high density effect induced by pressure plays a key role for their generation.

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Attempts to synthesize and/or theoretically predict new superhard materials are the subject of an intense research activity. The trials to deposit them in the form of films have just began. WB(2) (77 wt % WB(2) and 23 wt % WB(4)) and WB(4) (65 wt % WB(4) and 35 wt % WB(2)) polycrystalline bulk samples were obtained in this work via electron beam synthesis technique and, subsequently, used as targets for films preparation by the pulsed laser deposition method. The targets were irradiated by a frequency-doubled Nd:glass laser with a pulse duration of 250 fs. The films grown on SiO(2) substrates at 600 °C were characterized by X-ray diffraction, scanning electron and atomic force microscopies, and Vickers microhardness technique. The deposited films are composed of WB(4). The intrinsic film hardness, calculated according to the "law-of-mixtures" model, lies in the superhardness region 42-50 GPa.

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Spectroscopic and electrochemical properties of amorphous V 2 O 5 films, prepared by r.f. sputter deposition, were compared before and after electrochemical lithium intercalation. The films gave a cyclic voltammogram typical of vanadium pentoxide with two/three steps of reversible electrochromism (yellow-green-blue). The expected effect of lithiation on chemical state and surface composition was monitored using XPS. A careful curve-fitting procedure of the detailed spectra was adopted and the in-depth profile analysis of the intercalated films clearly showed their surface reorganization as a function of time and ultrahigh vacuum conditions. The first objective of this work was to establish the influence of lithium intercalation while minimising degradation effects due to its high reactivity with the atmosphere, taking advantage of the in situ sample transfer facility.