The present invention provides novel methods and compositions for the diagnosis and treatment of colon cancers. The in-line skate includes a boot and a tracking system attached to the sole of the boot. A computing device for facilitating accurate touch input targeting with respect to a touch-screen display includes a display component, a touch detection component, a targeting component that associates a touch with a click target, and an event detection component that associates the touch with one of a right click event, a left click event, or a drag event. One of the advantages of the apparatus and method is that marks generated around the electrical contact between the anode and the medical implant are minimized. The pass wavelength of each optical filter is set such that insertion loss distribution of the optical filters at the wavelengths is similar to a gain distribution of the injection light sources at the wavelengths.