kira kay's next story looks at the h.i.v. epidemic in ukraine, which has the highest rate of the disease in europe. >> brown: finally tonight, what's behind microsoft's decision to buy skype? the giant tech company announced today it was purchasing the internet telephone service for $8.5 billion, the largest deal in microsoft's 36-year history. in doing so, it will get access to skype's millions of users worldwide, who log on to communicate by video or phone over the web. to walk us through the deal, we turn to cecilia kang, technology reporter for the "washington post." welcome back. >> thank you. >> brown: $8.5 billion sounds like a a lot of money. >> it is. >> brown: what is behind microsoft's move here? >> microsoft has dominated in the 1990s the p.c.. it's the software giant for the p.c., the personal-computer generation, but it wants to be more relevant for the internet. it particularly wants to be more relevant for smart phones and tablets and the services offered up from these new devices that google and apple are dom

. >> brown: from kiev, special correspondent kira kay reports on the push to curb a growing epidemic. $you crane has la t highest h.i.v./aids rate in all of europe. half a million people may be infected. more than france, germany, and the united kingdom combined. >> lehrer: judy woodruff has the latest on the violence in syria, as government tanks shell residential neighborhoods. that's all ahead on tonight's "newshour." major funding for the pbs newshour has been provided by: >> i want to know what the universe... >> looks like. >> feels like. >> from deep space. >> to a microbe. >> i can contribute to the world by pursuing my passion for science. >> it really is the key to the future. >> i want to design... >> a better solar cell. >> i want to know what's really possible. >> i want to be the first to cure cancer. >> people don't really understand why things work. >> i want to be that person that finds out why. help protect your future with pacific life-- the power to help you succeed. >> and by the bill and melinda gates foundation. dedicated to the idea that all people deserve the

special correspondent kira kay has the story. >> reporter: in a clinic tucked away in a southern neighborhood of kyiv, vadim completes what has been his daily habit for three years. he's called into the doctor's office and given a dose of methadone. after a check to make sure vadim has swallowed it all, he's dismissed. vadim says this program has saved his life, not just by keeping him off illegal drugs but by keeping him from contracting h.i.v./aids. the logic of this substitution therapy is simple: the more drug users on methadone, the less sharing of needles, and thus fewer transmissions of h.i.v. kostiantyn pertsovskyi is an h.i.v. prevention worker. >> it is not just about getting pill once a day, but here people get consultations from social workers and they advised them, so that it really changed their behavior to less risky one not only to themselves but to the community as a whole. >> reporter: ukraine has the highest h.i.v./aids rate in all of europe. half a million people may be infected-- more than france, germany and the united kingdom combined. diagnoses here have doubled in the