An Alaska-based soldier from Arizona has been killed in Afghanistan.  The Department of Defense in a release Monday identified the soldier as Sgt. 1st Class Johnathan B. McCain of Apache Junction, Ariz.  The 38-year-old McCain died Sunday in Kandahar province from injuries he received from a roadside bomb while on mounted patrol.  McCain was stationed with the 1st Stryker Brigade Combat Team at Fort Wainwright in Fairbanks.