Scope of this Review Paper

The following sections deal with II the physical conditions in interstellar space, III observations of interstellar molecules and their interpretation, including relevant laboratory measurements, and Section IV experimental and theoretical investigations of the processes of formation and destruction relevant to interstellar molecules. This review covers primarily the interstellar matter proper and refers only briefly to observations of molecules in circum-stellar shells, or molecule formation in protostellar nebulae. Table 1 sets out certain quantities which are used in astronomy and are necessary to an understanding of this paper. 

Gas density in H atoms, expressed in terms of total density p, on the basis of observed cosmic element abundances 

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Mediators can exist free in solution physically entrapped behind a membrane - immobilized in a matrix along with the biocatalyst or covalently bound to a surface or polymer network, wherein the polymer can be conductive or insulating. - Detailed discussion of the various formats is outside scope of this review paper. However, selected immobilization chemistries reported in relation to enzymatic biofuel cells are reviewed in the sections below. 

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