Synthesis of TiO2 Thin Films: Relationship Between Preparation Conditions and Nanostructure

The influence of the synthesis conditions (pH, HF concentration, procedure of application of the voltage) during the anodization of Ti foils to produce TiO₂ thin films characterized by an ordered arrays of 1D nanostructures (nanorods, nanotubes) is discussed. Different types of 1D nanostructures could be obtained by changing the procedure of synthesis, as shown by field emission scanning electron microscopy images. The analysis of the current versus time curves during the procedure of synthesis provides indications on the sequence of processes occurring during the synthesis. It is also suggested that different growing mechanisms occur depending on the preparation, leading in turn to the different type of nanostructures observed. The relevance of this preparation method is related to the analysis of the relationship for oxide materials between nano-architecture and reactivity and gives the opportunity to prepare materials with an intermediate degree of complexity between model and applied catalysts.     

Flow-through 3D biofuel cell anode for NAD-dependent enzymes

NAD⁺-dependent enzymes require the presence of catalysts for cofactor regeneration in order to be employed in enzymatic biofuel cells. Poly-(methylene green) catalysts have proven to help the oxidation reaction of NADH allowing for the use of such enzymes in electrocatalytic oxidation reactions. In this paper we present the development of 3D anode based on NAD⁺-dependent malate dehydrogenase. The 3D material chosen was reticulated vitreous carbon (RVC) which was modified with poly-(MG) for NADH oxidation and it also accommodated the porous immobilization matrix for MDH consisting of MWCNTs embedded in chitosan; allowing for mass transport of the substrate to the electrode. Scanning electron microscopy was used in order to characterize the poly-(MG)-modified RVC, and electrochemical evaluation of the anode was performed.     

Frataxin Silencing Inactivates Mitochondrial Complex I in NSC34 Motoneuronal Cells and Alters Glutathione Homeostasis

Friedreich’s ataxia (FRDA) is a hereditary neurodegenerative disease characterized by a reduced synthesis of the mitochondrial iron chaperon protein frataxin as a result of a large GAA triplet-repeat expansion within the first intron of the frataxin gene. Despite neurodegeneration being the prominent feature of this pathology involving both the central and the peripheral nervous system, information on the impact of frataxin deficiency in neurons is scant. Here, we describe a neuronal model displaying some major biochemical and morphological features of FRDA. By silencing the mouse NSC34 motor neurons for the frataxin gene with shRNA lentiviral vectors, we generated two cell lines with 40% and 70% residual amounts of frataxin, respectively. Frataxin-deficient cells showed a specific inhibition of mitochondrial Complex I (CI) activity already at 70% residual frataxin levels, whereas the glutathione imbalance progressively increased after silencing. These biochemical defects were associated with the inhibition of cell proliferation and morphological changes at the axonal compartment, both depending on the frataxin amount. Interestingly, at 70% residual frataxin levels, the in vivo treatment with the reduced glutathione revealed a partial rescue of cell proliferation. Thus, NSC34 frataxin silenced cells could be a suitable model to study the effect of frataxin deficiency in neurons and highlight glutathione as a potential beneficial therapeutic target for FRDA.     

PECVD of h-BN and c-BN films from boranedimethylamine as a single source precursor

Boron nitride (BN) thin films have been successfully synthesised via low pressure plasma enhanced chemical vapour deposition (PECVD) by using boranedimethylamine, BH₃NH(CH₃)₂, as a single source precursor in the temperature range 280-550 °C in a nitrogen-argon atmosphere. The plasma power was optimised with the aim of obtaining suitable cubic/hexagonal phase ratios. The annealing of the h-BN films at temperatures up to 1000 °C in a nitrogen atmosphere, at normal pressure, gave rise to a complete transformation into the cubic phase. FTIR measurements provided a suitable method for identifying the structure of BN films. UV-vis spectroscopy was carried out in order to investigate the optical behaviour of the films.     

Superhydrophilic and tribological improvements of polymeric surfaces via plasma enhanced chemical vapor deposition ceramic coatings

The main object of this study is the treatment of polymeric (PVC, PC) surfaces with the aim of inducing enhanced superhydrophilic characteristics together with nanohardness features; this would allow polymeric surfaces to have longer durability and prevent the accumulation of dirt on the surface which could disable the proper use of these polymeric surfaces. Indeed plastic surfaces are difficult substrates to be covered effectively and functionalized, mainly due to their high sensitivity to heat treatments and irradiation in the UV-Vis range together with their inert behavior. Their functionalization is achieved through the deposition of ceramic coatings such as titania (TiO2), on the polymeric surfaces via PECVD (Plasma Enhanced Chemical Vapor Deposition) at low temperatures. Characterizations are carried out by contact angle analysis for the superhydrophilic characteristics, and by nanoindentation analysis for the tribological features. A cold PECVD discontinuous method allowed us to improve nanohardness, reaching a value of 1.39 GPa which is nearly ten times higher than that of the uncoated polymeric substrate, and seems a promising solution for improving uniformity of the coatings. Superhydrophilic behavior of the activated TiO2 surfaces showed contact angle values lower than 10 degrees.     

Effect of a pre-treatment of milk with high pressure homogenization on yield as well as on microbiological, lipolytic and proteolytic patterns of "Pecorino" cheese

The principal aim of this work was to compare Pecorino cheeses obtained from ewes' milk previously subjected to high pressure homogenization (HPH) at 100 MPa with those produced from raw and heat treated ewes' milk. The HPH milk treatment induced a significant increase of the cheese yield and caused a reduction of enterococci, lactococci and yeasts in the curds. Enterococci cell loads remained at lower levels in cheeses obtained from HPH milk over the ripening period. Analyses of free fatty acids, Sodium Dodecil Sulphate (SDS)-PAGE profiles, Gas Chromatography-Mass Spectrometry-Solid Phase Microextraction (GC-MS-SPME) measurements of volatile compounds and sensory traits evidenced that the pressure treatment can be regarded also as a useful tool to differentiate products obtained from the same raw material. In fact such a milk treatment induced a marked lipolysis, an early proteolysis, a relevant modification of the volatile molecule profiles and sensory properties of Pecorino cheese.     

Resource Allocation in Cognitive Radio Networks: A Comparison Between Game Theory Based and Heuristic Approaches

Cognitive Radio (CR) approach can be considered as a promising and suitable solution to solve in an efficient and flexible way the increasing and continuous demand of services and radio resources. This paper shows the potential benefits of the adoption of a cognitive radio strategy to the coexistence problem. Two different approaches have been considered: the first one is based on the Game Theory while the second one is formalized as a constrained maximum search and represent the optimum solution. The Game theory approach, suitable for a distributed implementation, provides performances comparable to the heuristic one which is a centralized optimization problem. The paper analyzes the performances of both approaches in terms of secondary rates and spectral efficiency provided by the secondary system.