The winner of the Small World in Motion competition was disqualified after the winning short video was reported to have been made with artificial intelligence. The video, submitted by Tsinghua University researcher Ning Xu, showed microscopic cilia moving in the airway of a child with primary ciliary dyskinesia (PCD), a rare hereditary disorder in which these hairs do not move properly and mucus is not cleared effectively. The video prompted scepticism in the scientific community soon after the winner was selected. Robert Hirst, a British scientist who has researched PCD for more than 20 years, said he immediately believed the video had been staged because the cells and cilia looked entirely different from those of PCD patients. The maker denied that the images were fake.