text:  That process, I'm told, will be closed to the press and take place a week before the convention later this month, which is unusual. Typically, cameras are in the room. That is NPR senior White House correspondent Tamara Keith. Tamara, thanks. You're welcome. A clinical trial is starting to test a drug taken by many so-called longevity enthusiasts. NPR's Alison Arbery explains why a dentist is leading the research.