In this task, you are given a sentence. You are expected to recognize the name of any form of chemical substances. Although there might be several correct answers, you need to write one of them.

Input: Consider Input: Synaptotagmin 1 is required for vesicular Ca(2+) /H(+) -antiport activity.

Output: Ca(2+)

Input: Consider Input: DNA topoisomerase IIalpha (TOP2A) inhibitors up-regulate fatty acid synthase gene expression in SK-Br3 breast cancer cells: in vitro evidence for a 'functional amplicon' involving FAS, Her-2/neu and TOP2A genes.

Output: fatty acid

Input: Consider Input: Encapsulation of Nod1 and Nod2 receptor ligands into poly(lactic acid) nanoparticles potentiates their immune properties.
Output: poly(lactic acid)