1. Institute of Nanoscience and Nanotechnology National Centre for Scientific Research-Demokritos GR-15341 Agia Paraskevi Greece
2. Greek Atomic Energy Commission GR-15341 Agia Paraskevi Greece
3. Section of Condensed Matter Physics, Department of Physics National and Kapodistrian University of Athens GR-15784 Athens Greece
4. Institute of Nuclear & Radiological Sciences & Technology, Energy & Safety National Centre for Scientific Research-Demokritos GR-15341 Agia Paraskevi Greece
5. Department of Medicine Democritus University of Thrace GR-68100 Alexandroupoli Greece