Stem cells are undifferentiated cells that can renew themselves through cell division and, under certain circumstances, can develop into differentiated organ-specific cells. Photograph: Getty Images

The human body is composed of about 37 trillion tiny units called cells, and there are about 200 different types of cells corresponding to the many di(...)

Japanese police officers standing on a Tokyo street. Photograph: iStock

It was a crime that once would have attracted little attention in Tokyo’s lurid undertow: police are this week hunting a man who used his smartphone t(...)

AI tales: At the Massachusetts Institute of Technology, a robot called Tega can tell stories to children of kindergarten age and learn from feedback. Photograph: MIT

Walking along a residential street one evening not long ago my attention was caught by a common enough scene. A woman was standing inside her front ga(...)

Volcanic lightning at an eruption of Mount Sakurajima, in this photo taken from Tarumizu city, Kagoshima prefecture, in southwestern Japan. The peak experiences hundreds of small eruptions a year. Photograph: Reuters/Kyodo

A volcano in Japan about 50km from a nuclear plant erupted on Friday, shooting ash nearly 2km into the night sky along with fountains of lava, but the(...)