Compositions and methods for the detection and treatment of autism and autistic spectrum disorder are provided. The use of the stilbene derivative of the present invention allows the fabrication of a blue-emissive light-emitting element with excellent color purity. The guide blade further includes at least one fluid channel by which fluid under pressure can be routed into the receptacle in order to move the sealing element from the storage setting into the sealing setting. The radiation conduit includes an entrance aperture connected by an inwardly tapering body to an exit aperture. Alternatively, the device may have non-cylindrical rollers that provide different rotational speeds at the pad surface, or the device may apply different pressures at different portions of the pad.