A compound having TRPV4 inhibitory activity or a pharmaceutically acceptable salt thereof is provided. The collimating lenses collimate and interfere light energy within a gap formed between the lenses as part of the interferometer. The method for operating a fuel cell system including a hydrogen gas oxygen fuel cell includes producing the hydrogen gas from a fuel and water emulsion. The pacemaker then assesses the contribution of particular heart chambers to pacing efficacy based on the alteration in the pacing mode and on any transient changes in the pacing efficacy. The condition of the ion introduction is varied in order to control the regions of the semiconductor layer to be added with the impurity and the concentration of the impurity therein. For example, techniques and tools are described that can be used to diagnose or test susceptibility to cognitive impairments in children or in elderly people.