You don't have to wait until after an infection to fight HIV. A technique known as pre-exposure prophylaxis has you taking preemptive medicine on a regular basis, greatly reducing the chances that HIV will take root in the first place. Needless to say, such a treatment could change the world if done well -- and the Bill & Melinda Gates Foundation wants to make sure that it's as easy as possible. They're investing $140 million in an Intarcia Therapeutics program that will develop an under-the-skin pump implant (you're looking at it above) that will deliver a steady stream of anti-HIV drugs in 6- or 12-month batches. Instead of having to remember to take medicine every day, you'd only have to top up once or twice a year.