Apple recently hired two medical sensor experts as the company continues to expand its research into wearable devices. A recent report notes Apple has hired Nancy Dougherty from Sano Intelligence and Ravi Narasimhan from Vital Connect. At Sano, Dougherty specialized in unobtrusive blood reading, working as the lead hardware engineer for a patch worn on the skin to measure blood levels. Narasimhan was vice president of research and development at Vital…