Graduates of Techstars-led accelerators, like the Sprint Mobile Health Accelerator, can now explore new opportunities with a world-renowned medical group. Techstars recently launched a post-accelerator program that allows startups to work with corporate partners, including now the Mayo Clinic. The program, called Techstars++, will allow companies that finish Techstars' three-month, mentor-led accelerator to spend two weeks on site with Mayo Clinic professionals to explore business opportunities…