This invention is directed to EP4 receptor selective prostaglandin agonists of the Formula I,wherein R2, X, Z and Q are as defined in the specification. The imaging device includes at least three types of color detecting photoelectric converting elements and a luminance detecting photoelectric converting element. In a hierarchical directory method, the desired data is retrieved by referring to respective tables T1 to T7, in succession. Built into the rib, padding, or both is a pocket or recess configured to accept a thermal cell.