Described herein are methods, devices, and microprocessors useful for predicting a hypoglycemic event in a subject. A portable auxiliary storage device includes a mode setting section, a mode detecting section and a memory access control section. Thereby, the present invention can guarantee that the user indeed knows the status of the residual electric energy of the battery. In the semi-permanent version, the intended effect can be controllably erased by removal of the nanostructure by simple chemical or physical means. A valve element is disposed within at least one of the bypass paths for substantially blocking air-flow through that bypass path when the associated blower motor is active.