The Mona Lisa (search), Leonardo da Vinci's masterpiece of a mysterious woman with a slight smile, is deteriorating, and the Louvre Museum (search) said Monday it will conduct an in-depth technical study to determine why. The thin panel of poplar wood that the work is painted on has become deformed since conservation experts last evaluated the painting, the Louvre said in a written statement. It did not say when the last evaluation was. The Louvre said the condition of the Mona Lisa was causing "some worry" and that a new study on the state of the work has been launched....