To provide a data communication device capable of performing a stable human body communication by bringing the human body into contact with electrodes or proximities thereof without requiring user’s attention when the data communication device held by the user is in the process of the human body communication. Compounds having a zinc-binding moiety, for example, an alpha-ketoepoxide group, such as an alpha-ketothio group, can inhibit histone deacetylase. Different types of the wobbles are formed on the grooves of either the user data area or the lead-out area, thereby preventing an optical pickup that performs recordingreproducing, from deviating from the user data area. Tensile stress is introduced by including a region of SiGe below the channel region of the NMOS transistors. The present invention also discloses use of axial groove heat pipes to cool the CT detector electronics because they have enhanced performance under revolving conditions.