Here, DG init is the free energy change for initiating a helix; each DG j NN ð Þ is the free energy increment of the jth type nearest neighbor (see Table 4 ) with n j occurrences in the sequence; m term-AU is the number of terminal AU pairs; DG termÀAU is the free energy increment per terminal AU pair; DG sym is 0.43 kcal/mol at 37 C for self-complementary duplexes and 0 for non-self-complementary duplexes. 