Complex sentence: His recent research has uncovered methods of repairing damaged brain tissue, and, in tandem with other scientists, demonstrating that stem cells derived from the blood of bone marrow and umbilical cords can be converted to neural cells.
Split into simpler sentences: His recent research has uncovered methods of repairing damaged brain tissue. In tandem with other scientists, he demonstrated that stem cells derived from the blood of bone marrow and umbilical cords can be converted to neural cells.