Objectives: Using dental Ti implants has become a well-accepted and used method for replacing missing dentition. It has become evident that in many cases peri-implant inflammation develops. The objective was to create and evaluate the antibacterial effect of silver nanoparticle (Ag-NP) coated Ti surfaces that can help to prevent such processes if applied on the surface of dental implants. Methods: Annealing I, Ag ion implantation by the beam of an Electron Cyclotron Resonance Ion Source (ECRIS), Ag Physical Vapor Deposition (PVD), Annealing II procedures were used, respectively, to create a safely anchored Ag-NP layer on 1x1 cm 2 Grade 2 titanium samples. The antibacterial effect was evaluated by culturing Staphylococcus aureus (ATCC 29213) on the surfaces of the samples for 8 hours, and comparing the results to that of glass as control and of pure titanium samples. Alamar Blue assay was carried out to check cytotoxicity. Results: It was proved that silver nanoparticles were present on the treated surfaces. The average diameter of the particles was 58 nm, with a 25 nm deviation and Gaussian distribution, the the filling factor was 25%. Antibacterial evaluation revealed that the nanoparticle covered samples had an antibacterial effect of 64.6% that was statistically significant. Tests also proved that the nanoparticles are safely anchored to the titanium surface and are not cytotoxic. Conclusion: Creating a silver nanoparticle layer can be an option to add antibacterial features to the implant surface and to help in the prevention of peri-implant inflammatory processes. Recent studies demonstrated that silver nanoparticles can induce pathology in mammal cells, thus safe fixation of the particles is essential to prevent them from getting into the circulation.

In this work, the performance of gold nanoislands was investigated for Localized Surface Plasmon Resonance (LSPR) and Surface Enhanced Raman Spectroscopy (SERS) applications. Nanoislands were generated by thermally annealing thin layers of gold (having thickness in the 6-12 nm range), which was previously deposited by vacuum thermal evaporation onto glass substrates. Gold nanoparticles (AuNP) were evaluated based on their plasmonic and SERS performance and morphological properties. Scanning Electron Microscopy (SEM) was used to measure the average particle size and average interparticle distance in order to correlate them with the obtained plasmonic/Raman capabilities. The technological parameters of nanoisland fabrication for optimal performances were also determined.

No abstract

It has been shown by the Auger depth profiling technique that the concentration profile at the initially sharp Si/Ge interface in amorphous Si/Ge multilayers shifted but remained still sharp after a heat treatment at 680 K for 100 h. At the same time the fast diffusion of Si resulted in the formation of an almost homogeneous Ge͑Si͒ amorphous solid solution, while there was practically no diffusion of Ge into the Si layer. This is direct evidence on the strong concentration dependence of the interdiffusion coefficient in amorphous Si/Ge system, and it is in accordance with the previous indirect result obtained from the measurements of the decay of the small angle Bragg peaks, as well as with finite difference simulations. © 2001 American Institute of Physics. ͓DOI: 10.1063/1.1331330͔Changes in atomic structures of amorphous semiconductors and their relationships to physical properties are currently of interest due to their useful optical and electronic features.1,2 Since most structural changes are related to atomic diffusion, any real understanding of the structural transformation, homogenization, etc., must be based on the knowledge of the diffusion processes. The study of diffusion in amorphous materials includes some difficulties. One of the main problems is related to the thermal stability of the amorphous phase; the diffusional measurements should be carried out at low temperatures for very short diffusion times in order to avoid structural changes due, e.g., to structural relaxation. Additionally, in amorphous semiconductors the mechanism of diffusion is also not fully understood.3-5 Thus, for example factors controlling the details of diffusional homogenization in amorphous Si/Ge multilayers are still under discussion. First of all the diffusional asymmetry ͑manifested in the strong concentration dependence of the interdiffusion coefficients͒, 6 the significant pore formation during the diffusional mixing, 7 and the possible role of diffusional stresses 8 are the most important factors indicating the need of a better understanding of the previous process.In this article interdiffusion in amorphous Si-Ge multilayered specimens is studied by Auger depth profiling. The primary objective of the present investigation is to observe the predicted asymmetric change of composition caused by the strong concentration dependence of the diffusion coefficients. Experimental results, obtained from small angle x-ray diffraction ͑SAXRD͒ measurements at different average compositions indicated a strong concentration dependence of the chemical diffusion parameters.9,10 Although such a strong concentration dependence inevitably should lead to a significant curvature on the ln(I/I 0 ) ͑I/I 0 is the normalized height of the first order SAXRD peak͒ versus time plots 11 ͑and to oscillatory behavior of the higher order peaks͒, later on the experimentally observed curvature was rather attributed by the same group to the effects of structural relaxation and coupling back effects of stresses of diffusional origin were also excluded....