1. Department of Fibre and Polymer Technology, Royal Institute of Technology, SE-100 44 Stockholm, Sweden
2. Department of Applied Physics, Aalto University, FIN-00076 Finland
3. School of Biotechnology, Royal Institute of Technology, AlbaNova University Centre, SE-106 91 Stockholm, Sweden
4. Wallenberg Wood Science Center, Royal Institute of Technology, SE-100 44 Stockholm, Sweden