Joanna Klimontko

Catalytic Gas-Phase Glycerol Processing over SiO2-, Cu-, Ni- and Fe- Supported Au Nanoparticles.

In this study, we investigated different metal pairings of Au nanoparticles (NPs) as potential catalysts for glycerol dehydration for the first time. All of the systems preferred the formation of hydroxyacetone (HYNE). Although the bimetallics that were tested, i.e., Au NPs supported on Ni, Fe and Cu appeared to be more active than the Au/SiO2 system, only Cu supported Au NPs gave high conversion (ca. 63%) and selectivity (ca. 70%) to HYNE.

Photofunctionalization of dental zirconia oxide: Surface modification to improve bio-integration preserving crystal stability

The use of zirconium oxide in dental implantology is rapidly increasing as it is regarded as being more aesthetical and biologically friendly than titanium oxide. The interaction of titanium oxide with cells and proteins has proven to be significantly affected by the inevitable atmospheric hydrocarbon contamination, defined as biological ageing. The latter has proven to be effectively reversed by UVC irradiation. Crystal structures of both Zr and Ti oxides are very similar, thus also ZrO2 is prone to contamination by hydrocarbons. In the present study we have characterized the chemical-physical changes occurring to ZrO2 after UVC irradiation. Firstly a reduction by 3-fold of carbon present on its surface. XRD analysis has indicated that UVC irradiation treatment does not affect the crystalline structure of ZrO2, suggesting that it is possible to improve cell attachment on the surface without sacrificing the mechanical strength of the material. In addition a chemical model of interaction of cell surface proteins with the almost carbon free ZrO2 surface obtainable after UVC irradiation is proposed, pointing to the important role likely played by integrins and RGD sequences originating in soluble proteins adsorbed at the cell/ZrO2 interface. Hence in clinical practice UVC photofunctionalization could improve the soft tissue seal around dental implants functioning as a valid barrier between implant and peri-implant bone, thereby improving the long-term success of implants.

Effect of Ball Milling on Structure and Magnetic Properties of Fe-Nb-B-Tb Bulk Nanocrystalline Alloys

It was shown that pulverization of the examined alloys cause a decrease of mean diameters of nanocrystallites, a change of the phase composition and affects magnetic properties. For the alloy with x=0.08 magnetization remanence at T=300 K increases about two times with remaining constant Hc while for x=0.12 Hc decreases from 1.16 t to 0.36 T. The observed effects were attributed to the phase structure changes and breaking of direct magnetic intergrain coupling