Abstract: The present invention provides sodium saccharin bound with a ligand, derivatives thereof, and a process for preparation thereof. According to the present invention, there is provided a compound which is specifically bonded to hypoxic tumors. Specifically, the compound having sodium saccharin (SAC) bound with a ligand compound, or derivatives thereof can be applied to a contrast agent for cancer diagnosis.

Abstract: A cordless telephone releases a telephone call, in case that a handset unit is engaged in the telephone call over a predetermined time even though a telephone conversation has been completed. During the telephone conversation, a base unit periodically transmits busy state inquiry data to the handset unit, and checks whether response data thereto is received or not within a predetermined time. If the response data is not received within the predetermined time, the speech loop is automatically cut off. Therefore, in case that the handset unit misoperates due to the damage or the discharge of the battery, the base unit forcefully releases the call so that the user may make a telephone call with the base unit or another handset unit.