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: We hypothesize that when this man developed type 2 diabetes , chronic polyuria due to nephrogenic diabetes insipidus was sufficient to precipitate hyperosmolar dehydration .
### Output Text:
We hypothesize that when this man developed type 2 diabetes , chronic polyuria due to nephrogenic diabetes insipidus was sufficient to precipitate hyperosmolar dehydration . 