Dhaka, Dec. 26 -- The wife of Pakistan's former Prime Minister Imran Khan is being held in conditions that could pose a serious risk to her physical and mental health, a UN expert warned Wednesday.Alice Jill Edwards, the United Nations' special rapporteur on torture and other cruel, inhuman or degrading treatment or punishment, urged the Pakistani authorities to take immediate action to address the situation.Khan and his wife Bushra Bibi were convicted of graft in January, and they were sentenced to 14 years and seven years in prison, respectively.And on Saturday, a Pakistani court sentenced them to 17 years for corruption involving gifts the jailed ex-premier received while in office.Both Khan and Bibi were handed a 10-year prison senten...