Looks like Clinton's lead is fairly stable at about 12%.
Assuming she wins New York, I can't see how Sanders gets nominated. He's too far behind.
http://www.bloomberg.com/politics/graphics/2016-delegate-tracker/
http://www.realclearpolitics.com/epolls/2016/president/democratic_delegate_count.html
Sanders does particularly well with caucus states, but there are few left. And the way the delegates are shared, Clinton's unlikely to lose the primary states by a wide enough margin to leave an open path to the nomination for Sanders. If he loses, I think he should step down after New York, or at latest Pennsylvania, although I guess he will wait until California.