Microencapsulated Osteoblasts Support Hematopoietic Stem/Progenitor Cell Expansion in Hypoxic Environment by Ke-Dong, S, Tian-Qing, L, Guo-Feng, Z, Shuang, W, Mei-Yun, F, Fang-Xin, S, Li-Li, Z, Xue-Hu, M, Zhan-Feng, C