Suchergebnisse

There are many subjective inferences regarding environment-related studies in modern studies of ancient military defense heritage, and the objective quantitative analysis of citadel site selection and layout has become the key to interpreting the environmental adaptability of citadels under defense strategies. Based on this, it has been proposed in this research that the site selection of ancient military citadels in a specific region (Zhejiang) has environmental adaptability characteristics. Firstly, an elevated hydrological overlay model was established by predicting and graphically verifying the ancient hydrological thresholds through geospatial analysis strategies. Secondly, the hydrological and topographical indicators of the regional environment where the military citadel is located were digitally extracted. Finally, correlation and weight influence calculations were performed for different environmental data. The environmental adaptability characteristics of the site layout of the Ming dynasty-era Zhejiang coastal defense military citadel, based on military defense needs, were obtained. In this way, we promote digital technology for the excavation, conservation and sustainable use of heritage resources.

Yue Song,1,* Kaifeng Lin,2,* Shu He,3,* Chunmei Wang,1 Shuaishuai Zhang,1 Donglin Li,1 Jimeng Wang,4 Tianqing Cao,1 Long Bi,1 Guoxian Pei1 1Department of Orthopedics, Xijing Hospital, The Fourth Military Medical University, Xi'an, China; 2Second Department of Orthopedics and Traumatology, Fuzhou General Hospital of Nanjing Military Area Command of Chinese PLA, Fuzhou, China; 3Department of Orthopedics, Xi'an Hong Hui Hospital, Xi'an, China; 4Department of Orthopedics, The 251st Hospital of Chinese PLA, Zhangjiakou, China *These authors contributed equally to this work Background and aim: As a newly emerging three-dimensional (3D) printing technology, low-temperature robocasting can be used to fabricate geometrically complex ceramic scaffolds at low temperatures. Here, we aimed to fabricate 3D printed ceramic scaffolds composed of nano-biphasic calcium phosphate (BCP), polyvinyl alcohol (PVA), and platelet-rich fibrin (PRF) at a low temperature without the addition of toxic chemicals.Methods: Corresponding nonprinted scaffolds were prepared using a freeze-drying method. Compared with the nonprinted scaffolds, the printed scaffolds had specific shapes and well-connected internal structures.Results: The incorporation of PRF enabled both the sustained release of bioactive factors from the scaffolds and improved biocompatibility and biological activity toward bone marrow-derived mesenchymal stem cells (BMSCs) in vitro. Additionally, the printed BCP/PVA/PRF scaffolds promoted significantly better BMSC adhesion, proliferation, and osteogenic differentiation in vitro than the printed BCP/PVA scaffolds. In vivo, the printed BCP/PVA/PRF scaffolds induced a greater extent of appropriate bone formation than the printed BCP/PVA scaffolds and nonprinted scaffolds in a critical-size segmental bone defect model in rabbits.Conclusion: These experiments indicate that low-temperature robocasting could potentially be used to fabricate 3D printed BCP/PVA/PRF scaffolds with desired shapes and internal structures and incorporated bioactive factors to enhance the repair of segmental bone defects. Keywords: three-dimensional printing, nano-biphasic calcium phosphate, polyvinyl alcohol, platelet-rich fibrin, bone substitutes, tissue engineering