Key Engineering Materials Vol. 415

Abstract: Through a few examples, we present a short review on properties and applications of TiO2 films deposited by various CVD processes. The constraints due to the growth process make difficult optimization of properties that were correlated with microstructures. We focus on the photocatalytic activity in the visible range and on the antibacterial behavior of these functional thin layers.

Abstract: In the present work a study on the TiO2 ordered structures was pursued using an electrolyte with a low water content (glycerol containing 4% H2O). The results led to the determination of two distinct states of TiO2 matrix structure: one of nanotubes for lower values of applied voltage and another of nanopores for higher values of applied voltage. These results are interpreted using three key investigation methods: potentiostatic method for TiO2 growth, atomic force microscopy and scanning electron microscopy for surface characterization.

Abstract: In this paper the elaboration and characterization of TiO2 nanotubes as a function of anodizing conditions are studied taking into consideration electrolyte composition and voltage. The obtained results show that the nanotubes dimensions and surface features depend on elaboration conditions. The technique of surface characteristics investigation (2D and 3 D images) was atomic force microscopy which permitted roughness and porosity evaluation.

Abstract: The aim of this study is to evaluate the influence of Nb amount on electrochemical behaviour and surface properties for Oxinium-like Zr-Nb biomedical alloys. Oxinium (heat treated Zr-2.5%Nb alloy) represents the newest metal-ceramic composite used in orthopaedic surgery for total hip and total knee replacement. We used potentiodynamic polarization measurements and electrochemical impedance spectroscopy (EIS) as electrochemical techniques and Vickers micro-hardness as surface properties evaluation technique.

Abstract: The paper reports the behavior of TiNbZrTa in biological solution which simulates the body conditions (SBF-simulated body fluids) with different pH values. It has determinate the ion release quantities in time in SBF and the passive layer transformation on the implant surface. The used techniques were ICP-MS, FT-IR and contact angle measurement.

Abstract: . The aim of this paper is to evaluate surface properties of natural temporary teeth from high polluted area by dynamics of balance hydrophil hydrophob in connection with surface analysis type atomic force microscopy (AFM). All the data were discussed in relation with the state of degradation of such teeth, taking into account that teeth are biological archive.

Abstract: Natural substances with polyphenolic structure exhibit remarkable antioxidant properties, being widely used in preventing various diseases. Among these, the oenotanins obtained from grapes seeds are proantocianidinic compounds with high molecular mass, water insoluble and as a result, rather difficult to be utilized. The aim of this paper was to produce their hydrosolubilization and the structure of the product resulted (enoxyl) has been investigated by MS, IR, UV-Vis spectroscopy. The antioxidant activity of oenotanins and enoxyl has been quantified by chemiluminescence technique, and the minimum concentration able to capture completely the free radicals has been also established.

Abstract: Photophysical studies on oxidative stress induced by illumination with ultraviolet (UV) light from artificial light sources, were performed on small unilamellar liposomes (SUVs) as models of biomembranes. Different liposoluble antioxidants were incorporated in the liposome bilayer during the lipid film preparation. The quercetin containing bilayers exhibited a high tolerance to photooxidative stress. The light-driven reactive oxygen species (ROS) effects on liposomal membranes were monitored by optical methods: UV-VIS absorption, fluorescence and chemiluminescence (CL), exploiting the spectral properties of chlorophyll a (Chla) embedded into some liposome bilayers (Chla/lipid molar ratio = 1/100). The interaction between Chla and the other liposome components resulted in changes in their absorption and emission fluorescence properties.

Abstract: In this paper we focused our studies on functionalization of DNA and of collagen with active molecules and thin film processing, their photostability in view of their further application in electronics and photonics as all optical switching elements, bioleds, optical memories, light amplifies, electro-optic modulators, etc. We have also addressed very important point for the practical application of these materials, not studied previously, which is the photo stability of these materials. If they have to work in photonic systems they have to exhibit an excellent stability in time and at the operation temperature range. The main interest for biopolymers arises from the fact that they are renewable, derived from waste of meat industry and they are biodegradable materials.