The paywall is here:<p><a href="http://www.pnas.org/content/111/22/7974.abstract" rel="nofollow">http://www.pnas.org/content/111/22/7974.abstract</a><p>The full paper is here:<p><a href="http://diyhpl.us/~bryan/papers2/paperbot/Wireless%20power%20transfer%20to%20deep-tissue%20microimplants.pdf" rel="nofollow">http://diyhpl.us/~bryan/papers2/paperbot/Wireless%20power%20...</a>