1043
Metallic cellular solids are a class of materials known for their high specific mechanical properties , being desirable in applications where a combination of high strength or stiffness and low density are important .
 material: Metallic; concept or principle: materials; concept or principle: mechanical properties; machanical property: strength; machanical property: stiffness; machanical property: density
Given options, please tell me the categories of all the listed entity words.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} 
 Entities: Metallic, materials, mechanical properties, strength, stiffness, density 
Answer:
 material: Metallic; concept or principle: materials; concept or principle: mechanical properties; machanical property: strength; machanical property: stiffness; machanical property: density