Sumaira Ashraf, Nasrin Akhtar, Muhammad A Ghauri, Muhammad I Rajoka, Zafar M Khalid and Irshad Hussain*
* Corresponding author: Irshad Hussain ihussain@lums.edu.pk
Nanoscale Research Letters 2012, 7:267 doi:10.1186/1556-276X-7-267