Consider the following premises. p <-> q_1. q_1 -> s_1. ~p. s_1 -> q_1. Can we infer ~s_1 or q from them?
 From s_1 -> q_1, q_1 -> s_1 we can infer s_1 <-> q_1. From p <-> q_1, ~p we can infer ~q_1. From s_1 <-> q_1, ~q_1 we can infer ~s_1. Finally, from ~s_1 we can infer ~s_1 or q. Therefore, the answer is yes.