A chemical mechanical polishing composition and method is provided, wherein the low-k dielectric material removal rate remains stable following the polishing of a 110th polished wafer in a plurality of wafers to be polished. The light emitting device includes a p-type semiconductor layer, an active layer, and an n-type semi-conductor layer that are stacked, a cover layer disposed on a p-type electrode layer to surround the p-type electrode layer, a conductive support layer disposed on the cover layer, and an n-type electrode layer disposed on the n-type semiconductor layer. The phase shifting component provides a predetermined phase shift to an RF signal at a first output terminal of the quadrature combined amplifier. Methods of treating gastroesophageal reflux disease are also disclosed. The radiation sensitive refractive index changing composition comprises a polymerizable compound, a non-polymerizable compound having a lower refractive index than the polymer of the polymerizable compound, and a radiation sensitive polymerization initiator. In the second position the sheath assembly distal leading edge is positioned axially adjacent or distal to the end of the shaft.