Consider the following premises. q_1 -> u_2. q_4 -> u_2. t. t -> q_4. Can we infer ~u_2 from them?
 From t -> q_4, t we can infer q_4. From q_4 we can infer q_4 or q_1. Finally, from q_4 -> u_2, q_1 -> u_2, q_4 or q_1 we can infer u_2, which contradicts ~u_2. Therefore, the answer is no.