Complex sentence: He has been laureated with Mexico's National Prize for Arts and Sciences (1997), UNESCO Science Prize (2001), and has chaired both the International Committee on Rheology (1984-88) and the Mexican Society of Rheology (1976-97).
Split into simpler sentences: He has been honored with Mexico's National Prize for Arts and Sciences (1997) and the UNESCO Science Prize (2001). Mena has chaired both the International Committee on Rheology (1984-88) and the Mexican Society of Rheology (1976-97).