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In vitro strips rather than a treated infant.\nexposure: Ibuprofen applied at low oxygen tension across gestational ages, with potassium and oxygen contractions\nevidence_span: {\"source_cache\": \"artifacts/ibuprofen-research/497895.abstract.txt\", \"locator\": \"Indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"9d0874e6d05ee46097aeebdc1f0b9024541aa1305a648d6b783c329108a0bf0f\", \"start_char\": 0, \"end_char\": 1229, \"text_sha256\": \"9d0874e6d05ee46097aeebdc1f0b9024541aa1305a648d6b783c329108a0bf0f\"}\n[ibu-p497895] Age-dependent changes in the response of the lamb ductus arteriosus to oxygen and ibuprofen. 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