When Dr. Boie Jalloh got the call to join the fight against Ebola in Sierra Leone, his friends told him he'd be crazy to sign on. It's a good thing he didn't listen. Aurelie Marrier Dunienville for NPR hide caption

itoggle caption Aurelie Marrier Dunienville for NPR

Sen. Charles Grassley, R-Iowa, and a Democratic colleague have introduced a bill that would require drugmakers and medical device companies to disclose payments made to physician assistants and nurses who can prescribe their products. Brendan Smialowski/AFP/Getty Images hide caption

itoggle caption Brendan Smialowski/AFP/Getty Images

Image of a mini-kidney formed in a dish from human induced pluripotent stem cells. Minoru Takasato/Nature hide caption

itoggle caption Minoru Takasato/Nature

In Boston, Edmund Hassan, a deputy superintendent of emergency medical services, and his colleagues regularly revive people who have overdosed on opioids. Jesse Costa/WBUR hide caption

itoggle caption Jesse Costa/WBUR

The model of a DNA stands on a desk during a press conference to announce the winners of the Nobel Prize in Chemistry 2015 on Wednesday at the Royal Swedish Academy of Sciences in Stockholm. Sweden's Tomas Lindahl, Paul Modrich of the US and Turkish-American Aziz Sancar won the Nobel Chemistry Prize for work on how cells repair damaged DNA. Jonathan Nackstrand/AFP/Getty Images hide caption

itoggle caption Jonathan Nackstrand/AFP/Getty Images