0000000000993799
AUTHOR
G. Conigliaro
Electronic Properties of Thermal Oxides on Ti and Their Influence on Impedance and Photoelectrochemical Behavior of TiO2 Nanotubes
Thermal oxidation of titaniumwas carried out at 350◦C, 450◦C, and 550◦C for 2 h or 12 h.X-rayDiffraction and Raman Spectroscopy suggest that the thermal oxides are scarcely crystallinewhen the annealing temperature is low, while both anatase and rutile are present for high annealing temperature and time. Photoelectrochemical measurements allowed estimation of a bandgap decreasing from 3.35 eV to 3.15 eV with increasing annealing temperature. The impedance spectra confirmed the formation of n-type semiconductors, with an impedance strongly decreasing on going from a reverse bias toward a forward bias regime. TiO2 nanotubes grown by anodizing Ti in NH4F and water containing ethylene glycol so…
Antagonism of Bacillus subtilis strain AG1 against vine wood fungal pathogens
Summary. Antagonistic substances produced by a Bacillus subtilis strain (AG1), which were previously found to slow down the growth of esca fungi in vitro, were produced in an artifi cial medium, isolated from the cell-free medium by precipitation and acidifi cation (to less than pH 2.5) and extracted from the precipitate with 96% ethanol. The crude extract employed in antibiotic assays confi rmed, in vitro, the antagonism of B. subtilis against Phaeoacremonium aleophilum and Phaeomoniella chlamydospora, and also showed antifungal activity toward Verticillium dahliae and Botryosphaeria rhodina.
The effect of Annealing Conditions on the Impedance and on the Photoelectrochemical behavior of TiO2 Nanotubes
Titanium oxide nanotubes (NTs) have attracted much attention during last decade due to their special characteristics such as one-dimensional highly ordered geometry with large surface area and good chemical and optical stability.
Pathogenicity and possible biological control of fungi associated to Botryosphaeria dieback of grapevine in Western Sicily
Botryosphaeria dieback is a widespread grapevine trunk disease caused by species of fungi within the family Botryosphaeriaceae. Symptoms of the disease include bud necrosis, leaf chlorosis, vascular discoloration of the wood, cankers and dieback. In 2013 typical symptoms of Botryosphaeria dieback was observed in Western Sicily and four species associated with the syndrome were isolated and identified as Diplodia seriata, Lasiodiplodia mediterranea, Neofusicoccum parvum and Neofusicoccum vitifusiforme. In order to fulfill Koch’s postulates, pathogenicity tests of eighteen isolates were performed on two-year grapevine cuttings of cv. Inzolia. Six months after inoculation all the Botryosphaeri…
Photoelectrochemical Evidence of Cu2O/TiO2 Nanotubes Hetero-Junctions formation and their Physicochemical Characterization
Cu2O/TiO2 nanotubes heterojunctions were fabricated by electrochemical deposition of cuprous oxide on TiO2 nanotubes arrays grown by anodizing. X-ray diffraction and Raman Spectroscopy analysis allows for identification of Cu2O, whose morphological features were studied by Scanning Electron Microscopy as a function of the charge circulated during the electrodeposition step. Photoelectrochemical measurements in aqueous solutions evidenced a red shift of the light absorption threshold of TiO2 nanotubes due to the presence of cuprous oxide even for very low circulated charges, while electrochemical impedance measurements proved a significant reduction of the electrode impedance due the presenc…
The development of sporangia of Phytophthora infestans
The dynamics of sporulation and zoosporogenesis of Phytophthora infestans in a naturally infected crop of potato cv. Maris Bard and on potted plants of the same cultivar infected artificially with the same fungus are described. Development of sporangiophores and sporangia was synchronous after induction. Migration of several nuclei from the sporangiophore into the sporangium initial was followed by nuclear division, then by degeneration of a proportion of the nuclei. Sporangia then became deciduous, developed papillae and became able to release zoospores in rapid succession. When infected leaves were detached and transferred from the field to moist Petri dishes, sporulation was at first syn…
Design and performance evaluation of an hybrid reservation-polling MAC protocol for power-line communications
This paper presents an hybrid reservation-polling MAC protocol able to effectively deal with the channel disturbances typical of Power-line communication systems. Channel access is controlled by a scheduler running on a centralized station. Fast retransmission of corrupted packets is employed to achieve high performance on Power-line channels characterized by frequent error bursts due to impulsive noise. The performance of our proposed mechanism are evaluated by means of simulation, for the more challenging case of time-sensitive traffic sources (voice calls). Results show that the system efficiency is virtually not affected by lightly to moderately disturbed PLC channel. Moreover, by sligh…
Multiscale Approach in Studying the Influence of Annealing Conditions on Conductivity of TiO2 Nanotubes
Titanium oxide nanotubes (NTs) have attracted much attention during last decade due to their special characteristics such as one-dimensional highly ordered geometry with large surface area and good chemical and optical stability.
Endophytic Fungi in Asymptomatic Vitis vinifera L. and their Effects on Plasmopara viticola
During a multi-year study on the life cycle of Plasmopara viticola to assess the typical epidemiology of downy mildew on grapevine (Vitis vinifera) in west Sicily (Italy), several leaves on which the downy mildew had collapsed were found and observed in a vineyard located in Marsala, in Trapani Province. An antagonistic fungus was isolated from these leaves and named A20; through its morphology, it was identified as a hyphomycete belonging to the genus Acremonium. The antagonism of A20 against the asexual and sexual spores of P. viticola, as well as endophytic nature of the genus Acremonium in V. vinifera were confirmed by further studies which have been carried out over the past decade. In…
Grapevine decline in Italy caused by Lasiodiplodia theobromae
The first report of a dieback of grapevine caused by Lasiodiplodia theobromae in Sicily (Italy) is given. About twelve per cent of the vines in the cv. Insolia vineyard surveyed, showed spur dieback, retarded growth and wood necrosis. Isolation trials and pathogenicity tests are briefl y reported, together with morphological, cultural and molecular characters on which identification was based.