An electronic device for detecting an object beneath a wall section of interest has an elongate rectangular base for temporarily mounting to the wall section of interest and for carrying a display panel to display a persistent image of the object. The system comprises a sensor unit having at least one antenna for transmission of a signal into a defined area of the structure. By using this liquid crystal composition, it is possible to provide a liquid crystal display element which has a high contrast, high-speed responsiveness, and good display quality in which image sticking and display defects are not generated. The sequences, referred to as minimum functional regions, or MFRs, are useful inter alia as therapeutic agents for treatment of sepsis and other pathologies caused by microorganisms such as sepsis andor in which microorganisms are contributory agents. Information about the object or objects within the security container is extracted by the system and conveyed to the control computer, where it is stored, before the container is dispensed to the user. For instance, when used in connection with a controller wired to the energy-consuming equipment, the gateway need only communicate wirelessly with the controller and does not necessarily need to be coupled to the energy-consuming equipment.