Vacuum polarization by fermionic fields in higher dimensional cosmic   string space-time
  In this paper we investigate vacuum polarization effects associated with charged massive quantum fermionic fields in a six-dimensional cosmic string space-times considering the presence of a magnetic flux running along its core. We have shown that for specific values of the parameters which codify the presence of the cosmic string, and the fractional part of the ratio of the magnetic flux by the quantum one, a closed expression for the respective Green function is obtained. Adopting this result, we explicitly calculate the renormalized vacuum expectation value of the energy-momentum tensors, $<T^A_B>_{Ren}$, and analyse this result in some limitting cases. 
J. Spinelly and E. R. Bezerra de Mello