Exemplary embodiments of the present invention provide light-emitting diodes having a distributed Bragg reflector. The transistor is used as a resistor so that the resistance of a light emitting element can be held by the transistor. Observing that the aneurysm has been obstructed may include determining a degree of obstruction, for example by comparing an area or volume of the contrast agent in a first image and a second image. The application module interface is the only interface required to connect the two B channels and one D channel to or from the telephone terminal and the add-on module. The positioning pin includes an upper part having a guard part and a lower part.