Medical workers are taking care of one of the twin girls after the operation on July 18, 2007 at the No. 303 Hospital of the People's Liberation Army in Nanning, capital of south China's Guangxi Zhuang Autonomous Region. July 20 - One of the conjoined twin girls in southwest China's Guangxi Zhuang Autonomous Region died of heart and lung failure on Thursday less than 48 hours after being separated from her sister.Four doctors at the No. 303 Hospital of the People's Liberation Army in Nanning spent six hours on Tuesday evening separating the twin's livers, repositioning the girls' hearts and dividing a shared intestine.The girls, who spent their first six days with their noses just inches apart, could finally sleep in separate incubators in intensive care as of early Wednesday morning, but they both remained in a critical condition.Doctors failed to save the life of one of the eight-day-old baby girls, who was born with complicated heart disease that led to heart and lung failure, according to Shi Dekun, a doctor in charge of the operation.The other girl is in a relatively stable condition now, but she still has to survive this crucial, and dangerous seven-day period, said Shi.Five doctors are taking care of the baby, who is breathing with the aid of a respirator.Shi said that ideally the surgery would be performed when the twins were two months old, but in this case they had no choice as the twins were ill with pneumonia.When the girls were born on July 11, they shared a common pericardium and part of a liver and intestine.