A light-emitting element includes a blue light-emitting function layer provided between an anode and a cathode, a red light-emitting function layer provided between the anode and the blue light-emitting function layer, and a carrier selection layer provided between the blue light-emitting function layer and the red light-emitting function layer. The present invention also relates to methods of treating ABC transporter mediated diseases using such modulators. During one time slot, the beacon signal is transmitted to one of the sectors, and during another one of the time slots, the beacon signal is transmitted to a different one of the sectors.