Described herein are polishing apparatus, polishing formulations, and polymeric substrates for use in polishing surfaces, and related methods. A circuit board assembly is electrically coupled to the AC port and the DC port, and includes an AC connector array coupled to the AC port, and a DC connector array coupled to the DC port. The user can identify the color of the ink of the ink cartridge, by touching the ink cartridge with hisher hand, and obtain information of the position where that ink cartridge should be set, by touching the cartridge setting section with hisher hand. The second solution contains at least one surfactant before the former contacts the first solution. The invention also relates to methods for preparing same and to the therapeutic use thereof. An electric motor and a planetary gear set are concentric with the first axis of rotation.