Noun [edit]. viola â(plural violas). ( 1 music) A stringed instrument of the violin family, somewhat larger than a violin, played under the chin, and having a deeper tone. ( 2 music) An organ stop having a similar tone. ( 3 music) A 10-string steel-string acoustic guitar, used in Brazilian folk music.oun [edit]. viola â(plural violas). ( 1 music) A stringed instrument of the violin family, somewhat larger than a violin, played under the chin, and having a deeper tone. ( 2 music) An organ stop having a similar tone. ( 3 music) A 10-string steel-string acoustic guitar, used in Brazilian folk music.
Dipalmitoylphosphatidylcholine (DPPtdCho) is a phospholipid (and a lecithin) consisting of two palmitic acids attached of a phosphatidylcholine head-group and is the major constituent of many pulmonary surfactants. It is zwitterionic by virtue of having a negative charge on the phosphate group and a positive charge on the quaternary ammonium group.
NaBH4-TMEDA as hydride source and catalytic PdCl2(dppf) in THF is an efficient system for the hydrodehalogenation of bromo(chloro)-heteropentalenes with one or two heteroatoms, while Pd(OAc)2/PPh3 is able to reduce reactive haloheteropentalenes, and PdCl2(tbpf) allows the removal of the 2-chlorine from a thiophene ring.