Methods and compositions for treating or preventing, the occurrence of senile dementia of the Alzheimer’s type, mild cognitive impairment, or other conditions arising from reduced neuronal metabolism and leading to lessened cognitive function are described. for a retention time of one hour is performed, a Vickers hardness at a position with a depth of 0. The interposition layer constitutes a first surface portion which is formed on at least a part of the region of the surface of the aluminum material and contains a carbide of aluminum. On the other hand, when a mobile station communicates data with the base station, the base station transmits a data channel and an individual control channel to the mobile station by using a beam whose directivity is controlled individually. A first connector connects the image display to the rigid body.