Acknowledging flaws in the entire supervising process would prompt firings and possible government budget cuts, which is why Riken has circled the wagons and heaped blame on Ms. Obokata, said Thomas Knöpfel, a founder of Riken’s Brain Science Institute and now a leading neuroscientist at Imperial College London. “It appears to me that Riken is more concerned about damage control and blame shifting” than about clarification, he said.

Mr. Knöpfel in part blamed the Obokata affair on a push by Riken to publish in high-impact journals rather than to focus on generating good science. “My observation was that Riken is driven by individual egos and interests beyond the healthy competition required for attaining a high scientific and ethical standard,” he commented.

For its part, Riken has said that it plans a thorough review of its procedures and personnel.

“Those who were not found to have been involved in research misconduct still bear a heavy responsibility for their administrative negligence, which allowed the research misconduct to occur,” it said in a statement. “These individuals will also be subjected to disciplinary measures.”

The news media have not escaped blame either. Desperate for a scientific success story, journalists hyped Ms. Obokata as a sort of academic idol similar to Japan’s army of twee, ephemeral female celebrities. Reporters who visited her laboratory noted that the walls had been painted pink and decorated with cartoon characters. Television images focused on her false eyelashes and a striking if impractical wide-sleeved apron. “They built her up, then knocked her down,” said Shohei Yonemoto, a professor at the Research Center for Advanced Science and Technology in the University of Tokyo.

Ms. Obokata declined to comment for this article. Naoki Namba, a spokesman for Riken, said she was still under contract but a committee set up to decide disciplinary measures would probably recommend dismissal. Mr. Sasai, her supervisor, also declined to comment. But in an April news conference, he appeared to shift some of the responsibility to Charles A. Vacanti, a Harvard University professor who supervised Ms. Obokata’s research and was a co-author of the Nature papers.

Dr. Vacanti has stood by the scientific content of the papers, which aimed to show that pluripotent stem cells could be created by the application of external stresses, such as a bacterial toxin or a weak acid bath. He has argued against withdrawing the papers and has said that, once the dust from the scandal has settled, the science underlying the phenomenon described as “stimulus-triggered acquisition of pluripotency” will “speak for itself.” (Such cells can theoretically be cultivated into any kind of living tissue, meaning they might eventually be used to create new human organs.)