( ( Gastric ulcers ) ( ( are ( located ( not ( ( ( in ( the duodenum ) ) but ) ( in ( ( the stomach ) itself ) ) ) ) ) ) . ) )
(ROOT (S (NP (JJ Gastric) (NNS ulcers)) (VP (VBP are) (VP (VBN located) (PP (RB not) (PP (IN in) (NP (DT the) (NN duodenum))) (CC but) (PP (IN in) (NP (NP (DT the) (NN stomach)) (ADVP (PRP itself))))))) (. .)))
Gastric ulcers are located not in the duodenum but in the stomach itself.
(ROOT (S (NP (JJ Gastric) (NN emptying)) (VP (VBZ is) (VP (VBN regulated) (PP (IN by) (NP (NP (PDT both) (DT the) (NN stomach)) (CC and) (NP (DT the) (NN duodenum)))))) (. .)))