COS from B-1 to F-1, any possibility? Thanks for reply!

I have been holding B-1 visas during the last two years and traveled to US for professional conferences a couple of times w/o any delayed stay. During the last 7 years, I also visited many other Western countries for professional conferences as well. Now I got an offer from an American University. Can I change my B-1 visa to F-1 status w/o leaving the US? Many thanks for replies!