Figure 2.

Data preprocessing in the AOP-helpFinder tool. Before identifying and scoring associations between a chemical and an adverse outcome pathway (AOP) event, text information collected from multiple sources (publications, databases) was preprocessed in order to obtain stemmed data, which were stored in a relational in-house database. Negation words (never, neither, no, not, did not, hasn’t, should not, …) were identified with squares surrounded with small dots, stop words (coordinating conjunctions, punctuations, most common words such as “the”) with squares surrounded with large dots, and “words to stem” with solid lines (e.g., files $\to$ file or finder $\to$ find, considering that a word has a single stem, namely the part of the word that is common to all its inflected variants).