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This review aims to identify the current status and the future directions of design-oriented AM technology in producing porous metallic structures for bone tissue repair , with a particular emphasis on topological design of internal architecture of porous metals for bone implants .
 manufacturing process: AM technology; engineering feature: porous metallic structures; concept or principle: bone tissue repair; engineering feature: topological design; machanical property: internal architecture; material: porous metals; application: bone implants
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:
 manufacturing process: AM technology; engineering feature: porous metallic structures; concept or principle: bone tissue repair; engineering feature: topological design; machanical property: internal architecture; material: porous metals; application: bone implants