Before revision: The effects of positive and negative hydrationof counterions (Na^{+ and Cs^{+} ) incorporated into the hydration shell of the DNA double helix have been studied using molecular dynamics approach .
After revision: The DNA double helix is a polyanionic macromolecule that in water solutions is neutralized by metal ions (counterions). The property of the counterions to stabilize the water network (positive hydration) or to make it friable (negative hydration) is important in terms of the physical mechanisms of stabilization of the DNA double helix. In the present research, the effects of positive hydration of Na^{+ and Cs^{+} ) incorporated into the hydration shell of the DNA double helix have been studied using molecular dynamics approach .