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: PGF2 alpha was also significantly higher in the outer medulla of jj rats with and without aspirin administration ( p less than 0 . 05 ) .
### Output Text:
<span class="chemical">PGF2 alpha</span> was also significantly higher in the outer medulla of jj rats with and without <span class="chemical">aspirin</span> administration ( p less than 0 . 05 ) . 