Two years ago, the office of Michelle Obama, the vice president for community relations at the University of Chicago Medical Center, published a glossy report detailing the improvements her office had made in the lives of local residents, in part by increasing ties to minority contractors Center administrators declined to disclose which businesses benefited; the report lists one -- Blackwell Consulting Services. In 2005, the center expanded its bidding process and invited African American businessman Robert Blackwell Sr. to join a competition to upgrade the center's intranet, the in-house equivalent of a Web site. His company, Blackwell Consulting, won contracts...