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: In the vitro human platelet aggregations induced by the agonists used in tests , TET and FAN showed the inhibitions dose dependently .
### Output Text:
In the vitro human platelet aggregations induced by the agonists used in tests , <span class="chemical">TET</span> and <span class="chemical">FAN</span> showed the inhibitions dose dependently . 