The capability of the TJ-II Flexible Heliac to obtain configurations with different magnetic parameters has been used in the last experimental campaign to introduce different rational values in the iota profile at several radial positions. Evidence of E x B shear near some rationals has been observed pointing to some possible explanation for transport barier formation. This issue is of utmost importance for so called "advanced" regimes in steady state plasmas. A description is also given of the last experiments conducted in TJ-II and their results.
