WASHINGTON — For more than a century, the study of dinosaurs has been limited to fossilized bones. Now, researchers have recovered 70-million-year-old soft tissue, including what may be blood vessels and cells, from a Tyrannosaurus rex. If scientists can isolate proteins from the material, they may be able to learn new details of how dinosaurs lived, said lead researcher Mary Higby Schweitzer of North Carolina State University. "We're doing a lot of stuff in the lab right now that looks promising,'' she said in a telephone interview. But, she said, she does not know yet if scientists will be able...