US Secretary of State Antony Blinken is on a visit to China - offering a mixture of friendliness and warnings. We assess US-China relations and ask what, if anything, this visit could change.Also in the programme: the father of a US-Canadian aid worker killed in Gaza tells us the message he'd like today’s memorial service to send to the world; and the possible dangers of yet another artificial sweetener - one that's hard to avoid if you like soft drinks, cakes or chewing gum.(MAGE: U.S.... Read this story