Pi Cubed isn’t really a calculator; it’s much better! The chalkboard-style interface is conducive to building equations, and it easily beats out other scientific calculators. Just don’t expect it to replace your graphing calculator.

I’m not a scientist or medical professional so I can’t attest to all of Papers’ merits, but I can tell you that it appears to be a robust app that comes with a fine pedigree: The OS X version of Papers won a 2007 Apple Design Award for best scientific application for the Mac. Since Papers for the iPhone syncs with the OS X version, it allows you to leverage scientific research already in hand and also includes several search engines so you can not only take your research library with you on the go, but also add to it.