Question: who was the african american scientist who created synthetic physostigmine
[{'answer': 'Percy Lavon Julian', 'provenance': [{'wikipedia_id': '430881', 'title': 'Percy Lavon Julian', 'start_paragraph_id': 0, 'start_character': 0, 'end_paragraph_id': 0, 'end_character': 18, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '430881', 'title': 'Percy Lavon Julian', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 518, 'bleu_score': 0.8900620841790461, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 11351514216824980212}, 'section': 'Section::::Abstract.'}]}]