1. Department of Chemical, Biological & Macromolecular Sciences, S N Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata 700 098, India
2. Department of Physics, Jadavpur University, 188, Raja Subodh Chandra Mullick Road, Jadavpur, Kolkata 700032, India
3. Research & Development Division, Dey's Medical Stores (Mfg.) Ltd, 62, Bondel Road, Ballygunge, Kolkata 700019, India