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Insulin-positive ductal cells do not migrate into preexisting islets during pregnancy
Liu Qun,Jiang Yinan,Zhu Lingyan,Qian Jieqi,Wang Chaoban,Yang Tianlun,Prasadan Krishna,Gittes George K.,Xiao Xiangwei 생화학분자생물학회 2021 Experimental and molecular medicine Vol.53 No.-
The adult pancreatic ductal system was suggested to harbor facultative beta-cell progenitors similar to the embryonic pancreas, and the appearance of insulin-positive duct cells has been used as evidence for natural duct-to-beta-cell reprogramming. Nevertheless, the phenotype and fate of these insulin-positive cells in ducts have not been determined. Here, we used a cell-tagging dye, CFDA-SE, to permanently label pancreatic duct cells through an intraductal infusion technique. Representing a time when significant increases in beta-cell mass occur, pregnancy was later induced in these CFDA-SE-treated mice to assess the phenotype and fate of the insulin-positive cells in ducts. We found that a small portion of CFDA-SE-labeled duct cells became insulin-positive, but they were not fully functional beta-cells based on the in vitro glucose response and the expression levels of key beta-cell genes. Moreover, these insulin-positive cells in ducts expressed significantly lower levels of genes associated with extracellular matrix degradation and cell migration, which may thus prevent their budding and migration into preexisting islets. A similar conclusion was reached through analysis of the Gene Expression Omnibus database for both mice and humans. Together, our data suggest that the contribution of duct cells to normal beta-cells in adult islets is minimal at best.
Numerical study of rock-breaking performance of cutters in heterogeneous sand cobble ground
Jin Guo,Xiangwei Kong,Liu Cheng,Xueyi Li 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.6
Further research into tunneling performance in heterogeneous sand cobble ground demands an accurate numerical model of actual formation. In this paper, the ground model composed of spherical sand and ellipsoidal cobble was constructed to study the rockbreaking performance by using the discrete element method. The shape and physical parameters of sand and cobble were obtained on the basis of field test data. Then, the ground model was constructed to simulate the rock-breaking process of the cutterhead. The results show that the center cutter has a high flat wear percentage. With the decrease in cobble content (CC), the cracks between cutters are not connected effectively, thereby resulting in lower rock-breaking quantity. Finally, the influences of CC on the optimal parameters and crack propagation were analyzed. The results indicate that the rock-breaking performance in the ground with a low CC can be improved by increasing penetration and reducing cutter spacing.
High‐gain polarization conversion metasurface
Aixin Chen,Xiangwei Ning,Xin Liu,Zhe Zhang 한국전자통신연구원 2019 ETRI Journal Vol.41 No.2
A novel analytical method based on the cavity mode theory to design a metasurface (MS) is proposed in this study. We carefully analyzed the phase and amplitude characteristics of the incident wave and transmitted wave, and successfully designed a circular polarization conversion MS by introducing a cutting structure with wider operation bandwidth and higher radiation direction gain compared with that of the original MS. For the measurements, a microstrip antenna operating at 2.4 GHz was used as the source antenna to verify the designed MS. The simulation and measurement results agree well with each other.
Zhu Jun,Nan Huaichun,Guo Xiangwei,Liu Penghui,Du Shaotong,Yang Ming 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.5
This paper designs a new MW-scale half direct-driven axial flux permanent magnet generator (HDDAFPMG), which incorporates the merits of compact structure and high power density.In order to improve the output voltage quality of the generator,a multi-objective optimization method of parameter hierarchical optimization mechanism and NSGA-II is used to optimize the key design parameters of the generator.By comparing the performance of initial and optimization model using Finite Element Method (FEM), it is found that the output voltage quality of the optimization model is significantly improved.In addition,the Halbach permanent magnet (PM) array is used to decrease the total harmonic distortion (THD) of voltage waveform and decrease the thickness of back iron.It is concluded that the generator with 60° magnetized Halbach PM array can decrease the THD of voltage waveform decreases from 2.27% to 0.46% and decrease the thickness of back iron from 36 mm to 15 mm, which is reduced by 58.33%.
Targeting treatment of bladder cancer using PTK7 aptamer-gemcitabine conjugate
Xiang Wei,Peng Yongbo,Zeng Hongliang,Yu Chunping,Zhang Qun,Liu Biao,Liu Jiahao,Hu Xing,Wei Wensu,Deng Minhua,Wang Ning,Liu Xuewen,Xie Jianfei,Hou Weibin,Tang Jin,Long Zhi,Wang Long,Liu Jianye 한국생체재료학회 2023 생체재료학회지 Vol.27 No.00
Gemcitabine (GEM) is one of the first-line chemotherapies for bladder cancer (BC), but the GEMs cannot recognize cancer cells and have a low long-term response rate and high recurrence rate with side effects during the treatment of BC. Targeted transport of GEMs to mediate cytotoxicity to tumor and avoid the systemic side effects remains a challenge in the treatment of BC.Based on a firstly confirmed biomarker in BC-protein tyrosine kinase 7 (PTK7), which is overexpressed on the cell membrane surface in BC cells, a novel targeting system protein tyrosine kinase 7 aptamer-Gemcitabine conjugate (PTK7-GEMs) was designed and synthesized using a specific PTK7 aptamer and GEM through auto-synthesis method to deliver GEM against BC. In addition, the antitumor effects and safety evaluation of PTK7-GEMs was assessed with a series of in vitro and in vivo assays.PTK7-GEMs can specifically bind and enter to BC cells dependent on the expression levels of PTK7 and via the macropinocytosis pathway, which induced cytotoxicity after GEM cleavage from PTK7-GEMs respond to the intracellular phosphatase. Moreover, PTK7-GEMs showed stronger anti-tumor efficacy and excellent biosafety in three types of tumor xenograft mice models.These results demonstrated that PTK7-GEMs is a successful targeted aptamer-drug conjugates strategy (APDCs) to treat BC, which will provide new directions for the precision treatment of BC in the field of biomarker-oriented tumor targeted therapy.