Compounds represented by Formula : 1or a pharmaceutically acceptable salt thereof, are phosphodiesterase 4 inhibitors useful in the treatment of asthma and inflammation. A brush may be rotatably secured to the body, at least partly outside of the body, and driven by the motor and configured to remove by abrasion at least a layer of a substrate having markings thereon. The reaction product described above may have the structure. The invention is also about a calibration target. Particle size D of the solid particles is 0. A method of fabricating a transistor and an integrated circuit using the inventive simplified scatterometry structure are also disclosed.