Consider the following premises. s_2 -> ~q. p_13 or u_2. ~p_13. q. t -> s_2. Can we infer ~u_2 from them?
 From s_2 -> ~q, q we can infer ~s_2. Finally, from p_13 or u_2, ~p_13 we can infer u_2, which contradicts ~u_2. Therefore, the answer is no.