1. Institute of Silicate Materials; Riga Technical University; Azenes 14/24 1048 Riga Latvia
2. Institute of Physics; University of Tartu; Riia 142 51014 Tartu Estonia
3. Estonian Nanotechnology Competence Center; Riia 142 51014 Tartu Estonia
4. Institute of Solid State Physics; University of Latvia; Kengaraga 8 1063 Riga Latvia
5. Institute of Physics; University of Latvia; Miera 32 2169 Salaspils Latvia
6. Riga Biomaterials Innovation and Development Centre; Riga Technical University; Riga Latvia