Most of those problems have been considered unsolvable for a long time. Recent advanced in artificial hearts and heart assist devices (LVADs) have shown that at

Most of those problems have been considered unsolvable for a long time. Recent advanced in artificial hearts and heart assist devices (LVADs) have shown that at least a small fraction of the problems can be solved. For the rest? I'm not even sure if we know if they are solvable or not.