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: Single dose of DOX was associated with increased cardiac disarrangement , necrosis , and DNA damage ( strand breaks ( SBs ) and oxidized pyrimidines ) and decreased TAP .
### Output Text:
Single dose of <span class="chemical">DOX</span> was associated with increased cardiac disarrangement , necrosis , and DNA damage ( strand breaks ( SBs ) and oxidized pyrimidines ) and decreased TAP . 