A mode coupler that enables low-loss coupling between optical modes of two waveguides with different index difference. The jointing compositions include a sealant composition and a long chain ester in an amount of about 0. a) an organic silicon compound which is at least one represented by formula RnSiX4-n. The roller coaters comprise roller coater carriages that carry applicator rolls between support rolls without the need to journal ends of the applicator roll. Applied to video, the PT descriptors provide a way to compare the temporal order of events, actions, or objects such as those represented in a scene transition graph, key-frame list, or event string.