From attempting to recast the public image of private equity to trying to forge a new investment firm, 10 individuals profiled in the June issue of Mergers & Acquisitions are making their marks on middle-market investing, Tamika Cody, Mary Kathleen Flynn and Danielle Fugazy report.  From the intro: To highlight a few: Pam Hendrickson, chief operating officer of the Riverside Co. and a director of the global Association for Corporate Growth, has been spreading the word on Capitol Hill, and across the country, that private capital matters to the growth of the U.S. economy.   Andrew Sheiner, a managing director…