Non-perturbative states in type II superstring theory from classical   spinning membranes
  We find a new family of exact solutions in membrane theory, representing toroidal membranes spinning in several planes. They have energy square proportional to the sum of the different angular momenta, generalizing Regge-type string solutions to membrane theory. By compactifying the eleven dimensional theory on a circle and on a torus, we identify a family of new non-perturbative states of type IIA and type IIB superstring theory (which contains the perturbative spinning string solutions of type II string theory as a particular case). The solution represents a spinning bound state of D branes and fundamental strings. Then we find similar solutions for membranes on $AdS_7\times S^4$ and $AdS_4\times S^7$. We also consider the analogous solutions in SU(N) matrix theory, and compute the energy. They can be interpreted as rotating open strings with D0 branes attached to their endpoints. 
Jan Brugues, Joan Rojo, Jorge G. Russo