Among other things, assays and methods of diagnosis and treatment of disease based on the surprising observation of an interaction between amyloid or its aggregates with the sodium channel are provided. The frame contains the light source and the light guide plate. The apparatus may further include a Z-axis location control board cooperatively arranged with the X-axis location control board and configured to move the X-axis location control board in an Z-axis direction, wherein the output heads alternatively protrude with different lengths along an Y-axis direction. The base is attachable to a base surface of the vehicle.