A mobile communication apparatus, and a computer program product, comprising a memory arranged to hold contact information, wherein items of said contact information are arranged in a tree structure comprising a plurality of logical levels is disclosed. Each participant conference display typically shows two content sectors under the control of the presenter and a selectable number of other content sectors under the control of the participant. The invention, which can be applied to both forward and reverse auctions, permits competing participants to selectively safeguard their respective positions in the event of inadvertent disconnection from the online auction system, or other circumstances that prevent them actively participating in a critical period of the auction event. The one or more printed circuit boards may include a ground plane to minimize electrical cross talk. In a lithium ion secondary battery having a positive electrode 1, a negative electrode 4, and a separator 7 holding an electrolytic solution, an adhesive 8 containing an organic vinyl compound having at least two vinyl groups per molecule is applied between the positive electrode 1 and the separator 7 and between the negative electrode 4 and the separator 7 and cured by reaction to join them.