Russian Bobsled Federation president Alexander Zubkov says Nadezhda Sergeeva has failed a doping test at the OlympicsPublishedFeb. 23, 2018 5:01 a.m. ETPYEONGCHANG, South Korea (AP) Russian Bobsled Federation president Alexander Zubkov says Nadezhda Sergeeva has failed a doping test at the Olympics.