Physicists make the purest silicon ever seen, solving a supply problem for research into quantum computers.

Liberia will receive an untested experimental drug, Zmapp, to treat people infected with Ebola, the government says following a request to the US.

Untested drugs can be used to treat patients infected with the Ebola virus, the World Health Organization says.

Four of the world's emerging economies have claimed that they are far ahead of developed countries in their efforts to slow climate change.