Peroxo-carbonates derived from molten alkali andor Group II metal salts, particularly carbonate salts are used as catalysts in oxidation and epoxidation reactions, transition metal compounds may be included to improve the selectivity of the reactions. A graphical user interface associated with the video game presents visual objects representing audio content in any format aggregated from a number of different sources. Ink is supplied from the gap between the plurality of ink fountain keys and the ink fountain roller to the ink supply path in accordance with rotation of the ink fountain roller at the time of printing. The engaging portion and the engaged portion form a through hole that penetrates in an insertion direction of the engaging portion.