1300
With the combination of the density-gradients from TO with a size optimisation , Daynes derived functionally graded trusB-structures that align with the isostatic lines i.e .
 engineering feature: functionally graded trusB-structures; concept or principle: isostatic lines
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: 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:
 engineering feature: functionally graded trusB-structures; concept or principle: isostatic lines