Consider the following premises. q_1 -> r_4. ~q_4. r_4 -> q_1. r_4 -> q_4. Can we infer ~q_1 from them?
 From r_4 -> q_4, ~q_4 we can infer ~r_4. From r_4 -> q_1, q_1 -> r_4 we can infer r_4 <-> q_1. Finally, from r_4 <-> q_1, ~r_4 we can infer ~q_1. Therefore, the answer is yes.