An air mass flow controller valve containing at least two air channels that deliver desired air mass amount from a single inlet to fuel cell through at least one channel of the at least two air channels. An inner surface extends between the first side and the second side, and faces radially oppositely the outer flow path surface. The antibody is particularly useful in cancer therapy where the therapeutic agent is selectively delivered to the tumor by increasing the tumorblood ratio of the polyethylene glycol containing compound.