http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Haiyun Chen,Jialong Liang,Xin Gu,Jiawen Zhou,Chunfeng Xie,Xianhui Lv,Rong Wang,Qing Liu,Zhiyuan Mao,Haijian Sun,Guoping Zuo,Dengshun Miao,Jianliang Jin 생화학분자생물학회 2020 Experimental and molecular medicine Vol.52 No.-
To study whether TGF-β1/IL-11/MEK/ERK (TIME) signaling mediates senescence-associated pulmonary fibrosis (SAPF) in Bmi-1-deficient (Bmi-1−/−) mice and determines the major downstream mediator of Bmi-1 and crosstalk between p16INK4a and reactive oxygen species that regulates SAPF, phenotypes were compared among 7-week-old p16INK4a and Bmi-1 double-knockout, N-acetylcysteine (NAC)-treated Bmi-1−/−, Bmi-1−/−, and wild-type mice. Pulmonary fibroblasts and alveolar type II epithelial (AT2) cells were used for experiments. Human pulmonary tissues were tested for type Ι collagen, α-smooth muscle actin (α-SMA), p16INK4a, p53, p21, and TIME signaling by using enzyme-linked immunosorbent assay (ELISA). Our results demonstrated that Bmi-1 deficiency resulted in a shortened lifespan, ventilatory resistance, poor ventilatory compliance, and SAPF, including cell senescence, DNA damage, a senescence-associated secretory phenotype and collagen overdeposition that was mediated by the upregulation of TIME signaling. The signaling stimulated cell senescence, senescence-related secretion of TGF-β1 and IL-11 and production of collagen 1 by pulmonary fibroblasts and the epithelial-to-mesenchymal transition of AT2 cells. These processes were inhibited by anti-IL-11 or the MEK inhibitor PD98059. NAC treatment prolonged the lifespan and ameliorated pulmonary dysfunction and SAPF by downregulating TIME signaling more than p16INK4a deletion by inhibiting oxidative stress and DNA damage and promoting ubiquitinproteasome degradation of p16INK4a and p53. Cytoplasmic p16INK4a accumulation upregulated MEK/ERK signaling by inhibiting the translocation of pERK1/2 (Thr202/Tyr204) from the cytoplasm to the nucleus in senescent fibroblasts. The accumulation of collagen 1 and α-SMA in human lungs accompanied by cell senescence may be mediated by TIME signaling. Thus, this signaling in aging fibroblasts or AT2 cells could be a therapeutic target for preventing SAPF.
Tao Jiang,Haiyun Jin,Zhihao Jin,Jianfeng Yang,Guanjun Qiao 한양대학교 세라믹연구소 2009 Journal of Ceramic Processing Research Vol.10 No.1
Machinable B₄C/BN ceramic composites were fabricated by a hot-pressing process at 1,850 ℃ for 1 h under a pressure of 30MPa. In this article, the mechanical property, thermal shock behavior and machinability of the B₄C/BN ceramic composites were investigated. The fracture strength and fracture toughness of B₄C/BN nanocomposites were significantly improved in comparison with B₄C/BN microcomposites. The Vickers hardness of B₄C/BN nanocomposites and B₄C/BN microcomposites decreased gradually with an increase in the content of h-BN, while the machinability of B₄C/BN nanocomposites and B₄C/BN microcomposites were significantly improved. The B₄C/BN ceramic composites with an h-BN content of more than 20 wt% exhibited excellent machinability. The thermal shock resistance of the B₄C/BN ceramic composites was much better than that of the B₄C monolith, and the thermal shock resistance of B₄C/BN nanocomposites was much better than that of B₄C/BN microcomposites. The thermal shock temperature difference (ΔTc) of the B₄C monolith was about 300℃, while the ΔTc of B₄C/BN microcomposites was about 500℃ and the ΔTc of B₄C/BN nanocomposites was about 600℃. Machinable B₄C/BN ceramic composites were fabricated by a hot-pressing process at 1,850 ℃ for 1 h under a pressure of 30MPa. In this article, the mechanical property, thermal shock behavior and machinability of the B₄C/BN ceramic composites were investigated. The fracture strength and fracture toughness of B₄C/BN nanocomposites were significantly improved in comparison with B₄C/BN microcomposites. The Vickers hardness of B₄C/BN nanocomposites and B₄C/BN microcomposites decreased gradually with an increase in the content of h-BN, while the machinability of B₄C/BN nanocomposites and B₄C/BN microcomposites were significantly improved. The B₄C/BN ceramic composites with an h-BN content of more than 20 wt% exhibited excellent machinability. The thermal shock resistance of the B₄C/BN ceramic composites was much better than that of the B₄C monolith, and the thermal shock resistance of B₄C/BN nanocomposites was much better than that of B₄C/BN microcomposites. The thermal shock temperature difference (ΔTc) of the B₄C monolith was about 300℃, while the ΔTc of B₄C/BN microcomposites was about 500℃ and the ΔTc of B₄C/BN nanocomposites was about 600℃.