President Barack Obama hosted a science fair at the White House on Monday. The president saw 35 projects from student teams from across the country who won various competitions, and one of those students is from the Bay Area. Ruchi Pandya is a senior at Lynbrook High in San Jose. Using tiny carbon nanofibers, Ruchi created a thumbnail-sized sensor that may one day save a lot of lives. “I can actually, with one drop of blood, tell you what a certain protein concentration in your bloodstream is. That’s an indicator for cardiac arrest,” Ruchi told KPIX 5 via Skype. Which...