The Massachusetts-based startup BrainCo has partnered with a Chinese school for a trial of its high-tech headband to monitor the brains of schoolchildren in class to make sure they are concentrating. The Focus 1 headband uses electroencephalograph (EEG) sensors to detect brain activity when the wearer is engaged in a task.  The devices were worn by 10,000 schoolchildren aged 10-17 during a recent 21-day trial in China. (