Indian wrestler Yogeshwar Dutt's bronze medal from the London Olympics 2012 upgraded to silver after Besik Kudukhov of Russia has been stripped off his medal for using banned substance.In a tweet, Yogeshwar said, 'Today morning I came to know that my Olympics medal has been upgraded to silver. I dedicate my medal to all my countrymen.'Earlier, Russian agency, flowrestling.org reports that, the four-time world champion and two-time Olympic medallist Kudukhov, who died in a car crash in 2013 in southern Russia, has been found positive for dope test conducted by the World Anti-Doping Agency.