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: Our findings , showing no interaction between capsaicin treatment and attentional modulation suggest that capsaicin - induced secondary hyperalgesia and attention might affect mechanical pain through independent mechanisms .
### Output Text:
Our findings , showing no interaction between <span class="chemical">capsaicin</span> treatment and attentional modulation suggest that <span class="chemical">capsaicin</span> - induced secondary hyperalgesia and attention might affect mechanical pain through independent mechanisms . 