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: Group ADR + LOS ( 6 ) received losartan ( 10 mg / kg / b . w . / day by gavages ) for 6 weeks and group ADR + LOS ( 12 ) for 12 weeks after second injection of ADR .
### Output Text:
Group <span class="chemical">ADR</span> + <span class="chemical">LOS</span> ( 6 ) received <span class="chemical">losartan</span> ( 10 mg / kg / b . w . / day by gavages ) for 6 weeks and group <span class="chemical">ADR</span> + <span class="chemical">LOS</span> ( 12 ) for 12 weeks after second injection of <span class="chemical">ADR</span> . 