The field theory limit of multiloop string amplitudes
  We report on recent progress in the use of string techniques for the computation of field theory amplitudes. We show how one-loop renormalization constants in Yang-Mills theory can be computed using the open spinning string, we review the calculation of two-loop scalar amplitudes with the bosonic string, and we briefly indicate how the technique can be applied to the two-loop vacuum bubbles of Yang-Mills theory. 
P.Di Vecchia, L. Magnea, R. Marotta, A. Lerda, R. Russo