(S (S (S (BASENP (DT The) (NN trial)) (VP (VBZ starts))) (SBAR (BASENP (DT a) (NN week)) (SBAR (IN after) (S (S (NP (BASENP (DT a) (JJ different) (NN trial)) (COMMA ,) (VP (VBG involving) (NP (BASENP (DT a) (NN microbicide) (NN gel)) (VP (VBN called) (S (BASENP (NNP Ushercell))))))) (VP (VBD was) (VP (VBN stopped)))) (SBAR (IN after) (S (NP (BASENP (JJR more) (NNS women)) (SBAR (WHNP (WP who)) (S (VP (VBD used) (BASENP (DT the) (NN gel)))))) (VP (VBD were) (VP (VBN found) (S (VP (TO to) (VP (VB be) (VP (VBN infected) (PP (VBN compared) (PP (TO to) (NP (BASENP (DT those)) (SBAR (WHNP (WP who)) (S (VP (VBD were) (VP (VP (VBN given) (BASENP (DT a) (JJ dummy) (NN gel))) (PP (IN as) (BASENP (NN placebo)))))))))))))))))))))) (PERIOD .))