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 multivariate analysis , a significant correlation between DBP reduction and worsening of the neurological score was found for the high - dose group ( beta = 0 . 49 , P = 0 . 048 ) .
### Output Text:
In multivariate analysis , a significant correlation between DBP reduction and worsening of the neurological score was found for the high - dose group ( beta = 0 . 49 , P = 0 . 048 ) . 