1701
We have also assessed whether surface modification on Ti64 can elicit similar in vivo response as porous Ta in a rat distal femur model for 5 and 12 weeks .
 surface modification, Ti64, as, Ta, model
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: manufacturing standard, machanical property, manufacturing process, material, engineering feature, process parameter, machine or equipment, application, process characterization, enabling technology, biomedical, concept or principle 
Text: {0} 
Answer:
 surface modification, Ti64, as, Ta, model