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: Catheterization abnormalities correlated well with morphologic damage ( r = 0 . 57 to 0 . 78 ) in a subgroup of patients in whom exercise hemodynamics were measured , and this relationship also exhibited a curvilinear , threshold configuration .
### Output Text:
Catheterization abnormalities correlated well with morphologic damage ( r = 0 . 57 to 0 . 78 ) in a subgroup of patients in whom exercise hemodynamics were measured , and this relationship also exhibited a curvilinear , threshold configuration . 