  Attraction between two indentical objects uniformly charged in solution seems
intuitively surprising on the one hand because we know that such objects do
repel in vacuum and on another hand because this simple mental picture is still
preserved within the Poisson-Boltzmann theory of ion-mediated interactions. We
will see, however, that by relaxing some contraints on the models used, one can
find ion-mediated attraction between uniformly charged objects in solution.
This allows to give some insights on the possible way two DNA double strands
attract each other in many biologically relevant cases.
