3D printing biomimeticmaterials and structures for biomedical applications

Over millions of years of evolution,nature has created organisms with overwhelming performances due to their unique materials and structures,providing us with valuable inspirations for the development of next-generation biomedical devices.As a promising new technology,3D printing enables the fabrication of multiscale,multi-material,and multi-functional threedimensional(3D)biomimetic materials and structures with high precision and great flexibility.The manufacturing challenges of biomedical devices with advanced biomimetic materials and structures for various applications were overcome with the flourishing development of 3D printing technologies.In this paper,the state-of-the-art additive manufacturing of biomimetic materials and structures in the field of biomedical engineering were overviewed.Various kinds of biomedical applications,including implants,lab-on-chip,medicine,microvascular network,and artificial organs and tissues,were respectively discussed.The technical challenges and limitations of biomimetic additive manufacturing in biomedical applications were further investigated,and the potential solutions and intriguing future technological developments of biomimetic 3D printing of biomedical devices were highlighted.

3D Printing of Nacre-Inspired Structures with Exceptional Mechanical and Flame-Retardant Properties

Flame-retardant and thermal management structures have attracted great attention duc to the requirement of high-temperature exposure in industrial,aerospace,and thermal power fields,but the development of protoctive fire-retardant structures with complex shapes to fit arbitrary surfaces is still challenging.Herein,we reported a rotation-blade casting-assisted 3D printing process to fabricate nacre-inspired structures with exceptional mechanical and flame-retardant properties,and the relatedi fundamental mechanisms are studied.3-(Trimethoxysilyl)propyl methacrylate(TMSPMA)modified boron nitride nanoplatelets(BNs)were aligned by rotation-blade casting during the 3D printing process to build the"hrick and mortar"architecture.The 3D printed structures are more lightweight,while having higher fracture toughness than the natural nacre,which is attributed to the crack deflection,aligned BN(a-BNs)bridging,and pull-outs reinforced structures by the covalent bonding between TMSPMA grafted a-BNs and polymer matrix.Thermal conductivity is enhanced by 25.5 times compared with pure polymer and 5.8 times of anisotropy due to the interconnection of a-BNs.3D printed heat-exchange structures with vertically aligned BNs in complex shapes were demonstrated for efficient thermal control of high-power light-emitting diocles.3D printed helmet and armor with a-BNs show exceptional mechanical and fire-retardant properties,demonstrating integrated mechanical and thermal protection.

International public opinion analysis of four olympic games:From 2008 to 2022

Since the rapid spread of the COVID-19 worldwide,the pandemic has led to a huge impact on global sporting events.As a major international event,the 2022 Beijing Winter Olympics has commonalities with the 2008 Beijing Olympics,the 2014 Sochi Winter Olympics,and the 2020 Tokyo Olympics in terms of international public opinion context and epidemiological background.In this study,over 1 million pieces of UGC(User Generated Contents)in Chinese and English languages were obtained from social media platforms such as Twitter,YouTube,as well as traditional mass media in various countries to compare the differences between the two languages in international public opinion.Using sentiment analysis,this study explores the evolution of international public opinion topics and sentiment differences among the above four Olympic Games.The analysis results show that:1)regardless of traditional mass media or online social media,there is a more obvious tendency of general politicization in the topics of the 2008 Beijing Olympics and 2022 Beijing Winter Olympics,and extreme emotional remarks of the 2022 Beijing Winter Olympics are more frequent;2)in the topic of political opinion involving China,international Chinese public opinion presents more negative sentiment than those in English;3)Among the topics involving COVID-19,the negative level of public opinion in Chinese and English is opposite for the 2020 Tokyo Olympics and the 2022 Beijing Winter Olympics;4)International public opinion on the topic of sports events is significantly more positive in Chinese than in English;5)YouTube’s Chinese opinion environment is better than English.