[en] The neutron drip line in the oxygen-magnesium region has been explored by the projectile fragmentation of a ⁴⁸Ca beam using the fragment separator LISE at GANIL. New neutron-rich isotopes, ³⁴Ne and ³⁷Na, have been observed together with some evidence for the particle instability of ³³Ne and ³⁶Na. Recent data on mass measurements of neutron-rich nuclei at GANIL and some characteristics of binding energies in this region are discussed. Nuclear binding energies are very sensitive to the existence of nuclear shells and together with the measurements of instability of double magic nuclide ²⁸O they provide information on changes in neutron shell closures of very neutron-rich isotopes from carbon up to calcium. The conclusion about rearrangements in neutron shell closures is given. The spectroscopic measurements can reveal details of the underlying microscopic structures, the in-beam γ-ray spectroscopy is an effective tool to check for shell closures. This result of the γ-ray energies of the first 2⁺ level for even-even nuclei for N in the range 12-32 is discussed