The Loop Space Homotopy Type of Simply-connected Four-manifolds and   their Generalizations
  We determine loop space decompositions of simply-connected four-manifolds, $(n-1)$-connected $2n$-dimensional manifolds provided $n\notin\{4,8\}$, and connected sums of products of two spheres. These are obtained as special cases of a more general loop space decomposition of certain torsion-free $CW$-complexes with well-behaved skeleta and some Poincar\'{e} duality features. 
Piotr Beben and Stephen Theriault
math.AT math.GT