There is provided a powder formulation for nasal delivery including a protein having a molecular weight of 10 kDa or greater and chitosan or a derivative thereof or a salt of chitosan or a salt of a derivative of chitosan. The pair of pressure units define a gloss nip therebetween through which the recording medium is passed to enhance glossiness of the fused image. The output signal changes state when the first power supply voltage equals a trip point of the comparator. The junction further comprises a rectifier region situated at an interface between the first electrode and the memristive region, and comprising a layer of temperature-responsive transition material that is substantially conductive at the switching voltage and substantially resistive at the reading voltage.