Carbon dioxide-containing gas such as flue gas and a carbon dioxide-rich stream are compressed and the combined streams are then treated to desorb moisture onto adsorbent beds and then subjected to subambient-temperature processing to produce a carbon dioxide product stream and a vent stream. To this end, the present invention provides a light emitting diode comprising a substrate; a first conductive semiconductor layer positioned on the substrate; and an AlxGa1\u2212xN buffer layer interposed between the substrate and the first conductive semiconductor layer and having a composition ratio x of Al decreasing from the substrate to the first conductive semiconductor layer. The present invention further relates to pharmaceutical compositions comprising the aforementioned compounds for administration to a subject suffering from HCV infection.