Novel pseudopeptide analogs of the insect allatostain neuropeptide family which possess biological activity mimicking that of the naturally ocurring neuropepetides are disclosed. The tubing receptacle is an extruded cross section of minimum thickness with a plurality of planar surfaces for heat transfer to thermally conductive heat transfer plates or other thermally conductive materials. Further, a portion of the effluent gas from zone B is recycled to the combustion bed A2, passing via a blower but without passing via said scrubbing section D, and a portion is recycled to the inlet to zone B, passing via said blower but not via said scrubbing section. When the load is driven, the resulting signal is AMPM modulated.