In the sentence extracted from biomedical literature, identify all the chemical entities. The required answer format is the same sentence with HTML <span> tags to mark up specific entities. 
### Entity Markup Guides:
Use <span class="chemical"> to denote a chemical.

### Input Text: Development of AKI was compared between groups with exact Chi2 - test and multivariate logistic regression analysis ( two - sided P < 0 . 05 ) .
### Output Text:
Development of AKI was compared between groups with exact Chi2 - test and multivariate logistic regression analysis ( two - sided P < 0 . 05 ) . 