Activating NPPT distillation with an infinitesimal amount of bound   entanglement
  We show that bipartite quantum states of any dimension, which do not have a positive partial transpose, become 1-distillable when one adds an infinitesimal amount of bound entanglement. To this end we investigate the activation properties of a new class of symmetric bound entangled states of full rank. It is shown that in this set there exist universal activator states capable of activating the distillation of any NPPT state. 
Karl Gerd H. Vollbrecht, Michael M. Wolf