15569
The paramagnetic activity came from a Gd - DTPA derivative that was grafted on the silica surface .
 Chemical: Gd - DTPA; Chemical: silica
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: Gd - DTPA; Chemical: silica