An apparatus includes a plurality of AND gates each to receive as input a bit of a first binary vector and a corresponding bit of a second binary vector, where the length of the first binary vector is not greater than the length of the second binary vector. The invention provides nanocarriers capable of stimulating an immune response in T cells andor in B cells. The channels are configured to hold at least a major portion of a length of a respective battery cell. The circular DNA template 150, 210, 310 to be amplified may comprise one or more polythymidine 320 residues, resulting in amplification products 170, 230, 250, 330, 410 containing multiple polyadenylate 340, 420 residues.