(Hillsboro, OR)  --  Washington County authorities say a Certified Nursing Assistant from Providence St. Vincent Medical Center is accused of sexually assaulting two patients.  Sheriff's deputies say 34-year-old Adeladilew Mekonen was arrested after two victims, ages 87 and 94, lodged complaints with the hospital.  Officials say Mekonen worked at the hospital from May until he was arrested, but is no longer employed there.  His bail is set at a quarter-million dollars.