Abstract: An object of the present invention is to provide a compound with an improved balance of S1P5 receptor agonist activity with respect to S1P1 receptor, and a form suitable for drug substances of pharmaceuticals. Provided is Compound I having high S1P5 receptor-selective agonist activity on the S1P1 receptor. In addition, the crystal forms of Compound I, the salts of Compound I, and the crystal forms of salts thereof disclosed in the present invention are provided as drug substances of pharmaceuticals.

Abstract: A T-shaped pole tip portion of an upper pole of a write element for a magnetic disk drive is provided. One end of the pole tip portion, constituting the bottom of the “T,” forms a narrow nose segment at an air bearing surface, while a wing segment at the opposite end of the pole tip portion constitutes the cross-bar top of the “T.” A transition segment extends between the nose segment and the wing segment. A yoke portion of the upper pole includes a surface that is parallel to the air bearing surface and recessed therefrom by a P3R depth. The transition segment does not widen significantly until after the P3R depth, accordingly, the wing segment is recessed from the air bearing surface by more than the P3R depth.