Apologetic but resolute in the face of intense international scrutiny of her stem cell research, Haruko Obokata stood by her claim Wednesday that she had discovered so-called STAP cells.

Appearing at a news conference at an Osaka hotel accompanied by her lawyers, the 30-year-old researcher at the government-backed Riken institute denied allegations that she falsified or fabricated data presented in research papers published in the British science journal Nature in January.

¡°I sincerely apologize for suspicions raised over my research papers and the enormous trouble caused to Riken, co-authors of the papers and many others due to my carelessness, sloppiness and immaturity,¡± she said. ¡°I think my mistakes were incredibly (immature) in the eyes of many researchers.