Boston--Advanstar Communications Inc. has acquired HTâthe Magazine for Healthcare Travel Professionals and HTâs Web site, www.healthcaretraveler.com, from Niche Publishing Inc. The magazine and Web site focus on career opportunities and lifestyle interests of health care travel professionals, who accept three- to six-month assignments at hospitals in various locations throughout the U.S. The deal is one of the few in b-to-b publishing this year, which has seen a dearth of mergers and acquisitions because of low valuations of properties. HT will be published 10 times this year. It has a controlled circulation of 40,000.