A method is provided for protection switching in an optical network. An array of tangential apertures are formed in the chamber housing to permit fluid to be turbulently introduced into the vortex chamber to create a vortical flow of fluid through the vortex chamber. First to third power source lines connected to pixel electrodes are provided between the cathode wiring lines and the effective area. The air intake system includes a forwardly disposed air inlet, which faces in the direction of travel of a vehicle powered by the engine. Methods for screening agents that enhance or modulate NELL-1 gene expression or NELL-1 protein production in a cell are also provided.