1220
The novelty is that it represents a structure-based rather than a boundary-based TO and constitutes a method to increase the specific stiffness of the primitive unit cell .
 machanical property: specific stiffness; concept or principle: unit cell
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:
 machanical property: specific stiffness; concept or principle: unit cell