In a pattern forming method for selectively forming an oxide layer on a substrate surface, the substrate surface is selectively coated with a coating layer. The one or more semiconductor lasers are directly or indirectly fixed to the package with solder, and the one or more optical components are directly or indirectly fixed to the package with a thin layer of adhesive having a thickness of less than or equal to 1 micrometer, and preferably a thickness within a range of 0. The distributing unit determines whether a packet sequence inversion in the control unit occurs, based on a result of comparison of the transmitting sequence information received and the transmitting sequence information held by the control unit, inhibiting the transmission of the stored packets to the transmitting interface when the packet sequence invention is detected. The mononucleoside phosphate compounds of the present invention are useful in preventing and treating epithelial tissue diseases or diseases or disorders associated with platelet aggregation.