Certain substituted urea derivatives selectively modulate the cardiac sarcomere, for example by potentiating cardiac myosin, and are useful in the treatment of systolic heart failure including congestive heart failure. The swing regulating member is configured to come in contact with the exposure member at a contact position that is more upstream than the exposure member and that is more separated from the photosensitive member than a contact position between the positioning member and the exposure member. The body may have a top surface and a bottom surface. A gate dielectric is formed on the laid open sidewall.