Artificial heart newer versions, such as the Heartmate II, developed by The Texas Heart Institute of Houston, provide continuous flow. These pumps (which may be centrifugal or axial flow) are smaller and potentially more durable and last longer than the current generation of total heart replacement pumps. Another major advantage of a VAD is that the patient keeps the natural heart, which may still function for temporary back-up support if the mechanical pump were to stop. This may provide enough support to keep the patient alive until a solution to the problem is implemented. In August 2006, an artificial heart was implanted
Human artificial chromosome resulted in a human artificial chromosome that is mitotically stable. 21HAC was also able to be transferred into cells from a variety of species (mice, chickens, humans). Using 21HAC, researchers were able to insert a herpes simplex virus- thymidine kinase coding gene into tumor cells. This "suicide gene" is required to activate many antiviral medications. These targeted tumor cells were successfully, and selectively, terminated by the antiviral drug ganciclovir in a population including healthy cells. This research opens a variety of opportunities for using HACs in gene therapy. In 2011, researchers formed a human artificial chromosome by truncating chromosome 14.