(S (S (BASENP (DT The) (NNS researchers)) (VP (VP (VP (VP (VBD incubated) (BASENP (DT the) (NNS kidneys))) (PP (IN in) (BASENP (DT a) (JJ specialized) (NN oven)))) (PP (IN for) (BASENP (NN 12) (NNS days)))) (S (VP (TO to) (VP (VB mimic) (NP (BASENP (DT the) (NNS insides)) (PP (IN of) (BASENP (DT a) (NN rat))))))))) (PERIOD .))