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The identification of the antibacterial action of nalidixic acid (nx) was central to the development of the quinolone antibacterial compounds. The ability of the nx naphthyridyl ring to interact with and inhibit some proteins has encouraged the investigation of similar structures in the search for more active compounds with less adverse effects. The possibility of structural modification by attachment of other biologically active moieties to the naphthyridyl ring of nx allowed the development of new active antimicrobial molecules. Hydrazone derivatives of nx can be synthesized easily based on the condensation of the hydrazide derivative of nx with the desired aldehyde or ketone. Only a few complexes with nx hydrazone derivatives have been described but for none were the crystal structures elucidated. The synthesis of a new one-dimensional CuII coordination polymer, namely catena-poly[[copper(II)-di-μ-chlorido-copper(II)-{μ-1-ethyl-N'-[(1H-imidazol-4-yl)methylidene]-7-methyl-4-oxo-1,4-dihydro-1,8-naphthyridine-3-carbohydrazidato}-[dimethanolcopper(II)]-{μ-1-ethyl-N'-[(1H-imidazol-3-yl)methylidene]-7-methyl-4-oxo-1,4-dihydro-1,8-naphthyridine-3-carbohydrazidato}] dichloride methanol tetrasolvate], {[Cu3(C16H15N6O2)2Cl2(CH3OH)2]-Cl2·4CH3OH}n, with the (1H-imidazol-4-yl)methylidene carbohydrazide derivative of nalidixic acid (denoted h4imi), is presented and its structure is compared to the density functional theory (DFT) optimized structure of free h4imi. The title structure presents an octahedral CuII ion on an inversion centre alternating along a polymer chain with a square-pyramidal CuII ion, with the two CuII centres bridged by two chloride ligands. Hydrogen bonds involving chloride counter-ions and methanol solvent molecules mediate the three-dimensional packing of the polymer. Comparison of the geometrical results from the structure analysis with those derived from a DFT study of the free ligand reveal the differences that arise upon coordination. [ABSTRACT FROM AUTHOR]

Abstract: Low temperature silicon dioxide layers (LTO), deposited on crystalline silicon substrates, and thermally densified at 750°C for 90min or 900°C for 30min, jointly with thermally grown silicon dioxide layers, were irradiated with low fluence 11MeV Ti ions. A selective chemical etch of the latent tracks generated by the passage of swift ions was performed by wet or vapour HF solution. The wet process produced conically shaped holes, while the vapour procedure generated almost cylindrical nanopores. In both cases thermal SiO2 showed a lower track etching velocity V t, but with increasing the densification temperature of the LTO samples, the V t differences reduced. LTO proved to be suitable for wet and vapour ion track formation, and, as expected, for higher densification temperatures, its etching behaviour approached that of thermal silicon dioxide. [Copyright &y& Elsevier]

Abstract: In this work x-cut Lithium Niobate crystals were implanted with 0.5MeV O ions (nuclear stopping regime), 5MeV O ions (sub-threshold electronic stopping regime) and 12.5MeV Ti ions (ion track regime) at the fluences required for the formation of a surface fully disordered layer. The damage depth profiles were determined by RBS-channeling. Wet etching was performed at room temperature in 50% HF:H2O solution. The data indicated an exponential dependence of the etching rate on the damage concentration. Independently of the damage regime, once random level in the RBS-channeling spectra was attained we measured the same etching rate (50–100nm/s) and the same volume expansion (∼10%) in all samples. These results indicate that the fully disordered layers obtained by electronic damage accumulation have the same chemical properties of those obtained by conventional nuclear damage accumulation and therefore they can be defined “amorphous”. The impressive etching selectivity of ion implanted regions makes this process suitable for sub-micro machining of Lithium Niobate. [Copyright &y& Elsevier]

Abstract: In this work latent ion tracks were produced in 0.5μm thermal SiO2/Si by Ti ion irradiation. The samples were subsequently etched both in aqueous and in vapor HF solution. As expected, the wet etching process resulted in conically shaped holes, whose superficial diameter increased linearly with the etching time, and was correlated to the track to bulk etching velocity ratio (v T/v B). A threshold for track development at about 3MeV (corresponding to an electronic stopping power of 192eV/Å) was obtained. The velocity ratio then increased with the energy to v T/v B ≅1.6 at 12.5MeV (440eV/Å). For the vapor etching process, cylindrical pores were obtained, with an almost constant diameter of 20–30nm, until the SiO2/Si interface was reached. Subsequently the pore diameter quickly increased, with a rate much higher than both v T and v B. The threshold for track development was again at 3MeV, and the velocity ratio increased with the energy to v T/v B ≅5.5 at 12.5MeV. The track yield was about 100% for all the energies above the threshold. [Copyright &y& Elsevier]

Abstract: We report on the successful post-implantation annealing of 4H-SiC samples that were implanted at elevated temperature with high-dose Al implants. Anneals at temperatures up to 1700°C were conducted in a silane ambient at a process pressure of 150Torr using a cold wall CVD reactor. A series of 30min anneals were performed in 3% silane premixed in 97% UHP argon (Ar), which was further diluted in a 6slm Ar carrier gas. The surface morphology of the samples was studied via plan-view secondary electron microscopy (SEM) and atomic force microscopy (AFM). The resulting surface morphology showed no evidence of step bunching or any other surface degradation. We also report the electrical characterization of Al+ implanted p+/n 4H-SiC diodes realized on samples that were annealed at 1600°C. The current–voltage characteristics of the p+/n diodes and the resistivity of the implanted layer were measured at room temperature. Most of the diodes had a turn-on voltage of 1.75V, with ideality factors of up to 1.2 and very low reverse leakage current at −100V, corresponding to an average reverse leakage current density of (9.7±0.4)×10−9 A/cm2. The breakdown voltage was near the theoretical value for an epitaxial 4H-SiC layer. However, the resistivity value of the implanted Al+ layer was 11Ωcm, which was an order magnitude higher than the expected value. [Copyright &y& Elsevier]

The role of the heating rate in the postimplantation annealing process of SiC was investigated. Structural and electrical properties of an Al+ implanted junction in n-type 4H–SiC were studied for a 30 min annealing at 1600 °C in argon atmosphere and changing the heating rate between 7 and 40 °C/s. With the increasing of the heating rate the surface roughness increases, but the electrical performance of the devices improves. In particular, the faster ramp-up rate reduces the sheet resistance of the implanted layer of about 40% with respect to the slowest process and significantly reduces the leakage current of the diodes. [ABSTRACT FROM AUTHOR]

Swine dysentery is a mucohaemorrhagic colitis of pigs caused by infection with Brachyspira hyodysenteriae. The disease can be controlled by treatment with antimicrobial agents, with the pleuromutilins tiamulin and valnemulin being widely used. In recent years, the occurrence of B. hyodysenteriae with reduced susceptibility to these drugs has been increasing. The aim of this study was to determine temporal changes in genetic groups and pleuromutilin susceptibility amongst B. hyodysenteriae isolates from Italy. Multilocus sequence typing (MLST) was performed on 108 isolates recovered from 87 farms in different regions of Italy from 2003 to 2012, and their minimum inhibitory concentrations (MICs) for tiamulin and valnemulin were determined. Logistic regression was performed to assess associations between susceptibility to the two antimicrobial agents and genetic group, year and region of isolation. The isolates were allocated to 23 sequence types (STs), with five clonal clusters (Ccs) and seven singletons. More than 50% of isolates were resistant to both pleuromutilins (MIC >2.0 pg/mL for tiamulin and >1.0 gg/mL for valnemulin). All 10 isolates in ST 83 were resistant; these were first isolated in 2011 and came from nine farms, suggesting recent widespread dissemination of a resistant strain. Significant associations were found between the proportion of pleuromutilin susceptible isolates and the genetic group and year of isolation. Although resistant isolates were found in all Ccs, isolates in Ccs 2 and 7 were over five times more likely to be susceptible than those in the other Ccs. A significant trend in the reduction of susceptibility over time also was observed. [ABSTRACT FROM AUTHOR]

Abstract: High energy medium-light ion implantation was applied on both z-cut Er:LiNbO3 and Er3+–Yb3+ co-doped phosphate glasses, in order to fabricate optical waveguides on optically amplifying media. Preliminary results obtained with Er:LiNbO3, implanted with 3.9MeV Carbon ions, have demonstrated the possibility to fabricate good quality waveguides, the optical characteristics of which depend on implantation fluence and post-annealing process. Er3+–Yb3+ co-doped phosphate glass substrates were implanted with both 2.8MeV Carbon ions, at fluences ranging from 3×1014 ions/cm2 to 1×1015 ions/cm2, and with 3.4MeV Oxygen ions at a fluence of 1×1015 ions/cm2. Also in this case, planar optical waveguides were formed, but, under the as-reported implantation conditions, the possibility to tailor the refractive index profiles was very reduced. In this work, the optical properties of the integrated optical waveguides obtained on different doped substrates are examined. [Copyright &y& Elsevier]

Aim: To assess fundus autofluorescence (AF) for differential diagnosis of macular pseudoholes (MPH) and lamellar macular holes (LMH) evaluated by optical coherence tomography (OCT) as the "gold standard". Methods: The files on 50 eyes of 46 consecutive patients diagnosed by OCT as having a foveal defect with residual retinal tissue at the bottom were reviewed. Retinal thickness was measured at the foveal centre and 750 μm temporally and nasally to differentiate further MPH and LMH. The corresponding corrected AF images were then evaluated. Eyes with either macular pucker or stage la impending macular hole served as controls. Results: OCT measurements allowed the classification of two different profiles: 28 eyes classified with MPH had macular centres and perifoveal retinas that were significantly thicker than the 22 eyes classified with LMH. The corrected value of the foveal AF intensity was not significantly different between the two groups. In addition, the AF did not correlate with the thickness of the retinal tissue at the base of either MPH or LMH eyes. None of the control eyes showed foveal AF. Conclusions: The findings suggest that OCT data must be interpreted with caution when differentiating between MPH and LMH. In this series, the two groups showed similar foveal AF. AF imaging may add useful information to the differential diagnosis of MPH from LMH: the presence of foveal AF is consistent with a loss of foveal tissue and therefore a diagnosis of LMH. [ABSTRACT FROM AUTHOR]