Complex sentence: Lifespan of LED emitters is reduced by high operating temperatures--in the absence of a heat sink LED filament bulbs may use a high thermal conductivity gas inside the bulb to aid heat dissipation.
Split into simpler sentences: Lifespan of LED emitters is reduced by high operating temperatures. In the absence of a heat sink, LED filament bulbs may use a high thermal conductivity gas inside the bulb to aid heat dissipation.