▁hydro gen ▁gas ); ▁thus , ▁maintain ing ▁an h yd r ous ▁conditions ▁during ▁these ▁re actions ▁is ▁important . ▁Low ▁mole cular ▁weight ▁sil anes ▁are ▁often ▁py roph or ic . ▁Pol ym er ic ▁hyd ros il anes , ▁such ▁as ▁polym eth yl h yd ros il ox ane ▁( PH MS ) ▁may ▁be ▁employed ▁to ▁facil itate ▁separation ▁of ▁the ▁reduced ▁products ▁from ▁sil icon - cont aining ▁by products . ▁( 1 8 ) ▁ ▁References ▁ ▁Category : Organ ic ▁re actions <0x0A> </s> ▁Under ground ▁Sound ▁of ▁Lis bon ▁( s ometimes ▁short ened ▁to ▁US L ) ▁is ▁a ▁collaboration ▁between ▁Portuguese ▁house ▁music ▁produ cers ▁R ui ▁da ▁Silva ▁( then ▁known ▁as ▁Doctor ▁J ) ▁and ▁DJ ▁V ibe ▁( real ▁name ▁T ó ▁Pere ira ). ▁It ▁was ▁active ▁between ▁ 1 9 9 3 ▁and ▁ 2 0 0 1 . ▁In ▁ 2 0 1 4 ▁US L ▁returned ▁together ▁to ▁act ▁live ▁in ▁Rock ▁in ▁Rio ▁Lis boa ▁Electron ic ▁Stage . ▁ ▁The ▁du o ▁started ▁working ▁together ▁in ▁ 1 9 9 3 ▁by ▁found ing ▁Ka os ▁Records , ▁the ▁first ▁Portuguese ▁electronic ▁music ▁label , ▁with ▁prom oter ▁Ant ón io ▁C un ha . ▁They ▁released ▁their ▁first ▁record ▁as ▁Under ground ▁Sound ▁of ▁Lis bon , ▁Chapter ▁One , ▁in ▁ 1 9 9 4 , ▁although ▁at ▁that ▁time ▁they ▁also ▁signed ▁their ▁production ▁work ▁as ▁L HT ▁(