. >> woodruff: health correspondent betty ann bowser reports on some patients who developed severe side effects after taking certain anti- bacterial drugs. >> it's hard tonow how many americans are harmed by quinolones, or any prescription drugs for that matter, because the u.s. has no accurate way to track them. >> brown: as al-qaeda names a successor to osama bin laden, we look at the new leader and the state of the terrorist organization. >> woodruff: and, from thailand, we follow an unlikely escape route for thousands of north koreans. that's all ahead on tonight's "newshour." major funding for the pbs newshour has been provided by: >> auto companies make huge profits. >> last year, chevron made a lot of money. >> where does it go? >> every penny and more went into bringing energy to the world. >> the economy is tough right now, everywhere. >> we pumped $21 million into local economies, into small businesses, communities, equipment, materials. >> that money could make a big difference to a lot of people. >> and by the bill and melinda gates foundation. dedicated to the idea that all

. >> warner: betty ann bowser reports on a colorado hospital where medical mistakes are rare. >> one in three americans are at risk of a hospital acquired infection or will become a victim of a medical error. this hospital in denver is doing something about that. >> brown: ray suarez explores the prospect of another tech bubble. this time from social media websites. >> warner: and we get a rare view of dissent in china, following a new surge of protests by young people and labor union members. >> brown: that's all ahead on tonight's "newshour." major funding for the pbs newshour has been provided by: >> auto companies make huge profits. >> last year, chevron made a lot of money. >> where does it go? >> every penny and more went into bringing energy to the world. >> the economy is tough right now, everywhere. >> we pumped $21 million into local economies, into small businesses, communities, equipment, materials. >> that money could make a big difference to a lot of people. >> and by the bill and melinda gates foundation. dedicated to the idea that all people deserve the chance to live