**Exhibit      31.1**

**Certification        Under Section 302**

|   |                        a) designed such disclosure controls and procedures, or caused such                  disclosure controls and procedures to be designed under our supervision,                  to ensure that material information relating to the registrant,                  including                  its consolidated subsidiaries, is made known to us by others within                  those                  entities, particularly during the period in which this report is                  being                  prepared; |
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|   |                        b)  paragraph omitted pursuant to SEC Release Nos. 33-8760 and                  34-54942;                                                                                                                                                                                                                                                                                                                                                                                                                                 |
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|   |                        c) evaluated the effectiveness of the registrant’s disclosure                  controls and procedures and presented in this report our conclusions                  about                  the effectiveness of the disclosure controls and procedures, as                  of the end                  of the period covered by this report based on such                  evaluation; and                                                                                                                   |
|   |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |
|   |                        d) disclosed in this report any change in the registrant’s internal                  control over financial reporting that occurred during the registrant’s                  most recent fiscal quarter (the registrant’s fourth fiscal quarter in the                  case of an annual report) that has materially affected, or is reasonably                  likely to materially affect, the registrant’s internal control over                  financial reporting; and                   |

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| Date:                  May 14, 2007  | By:                                                                                                                                    | /s/                  Noah Berkowitz, M.D., Ph.D.  |
|                                      | Noah                  Berkowitz, M.D., Ph.D.President                  and Chief Executive Officer(principal                  executive officer) |

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