Erythropoietin-Modified Mesenchymal Stem Cells Enhance Anti-fibrosis Efficacy in Mouse Liver Fibrosis Model

Wang Xianyao,Wang Huizhen,Lu Junhou,Feng Zhanhui,Liu Zhongshan,Song Hailiang,Wang Heng,Zhou Yanhua,Xu Jianwei 한국조직공학과 재생의학회 2020 조직공학과 재생의학 Vol.17 No.5

BACKGROUND: Mesenchymal stem cell (MSC)-based cell transplantation is an effective means of treating chronic liver injury, fibrosis and end-stage liver disease. However, extensive studies have found that only a small number of transplanted cells migrate to the site of injury or lesion, and repair efficacy is very limited. METHODS: Bone marrow-derived MSCs (BM-MSCs) were generated that overexpressed the erythropoietin (EPO) gene using a lentivirus. Cell Counting Kit-8 was used to detect the viability of BM-MSCs after overexpressing EPO. Cell migration and apoptosis were verified using Boyden chamber and flow cytometry, respectively. Finally, the anti-fibrosis efficacy of EPO-MSCs was evaluated in vivo using immunohistochemical analysis. RESULTS: EPO overexpression promoted cell viability and migration of BM-MSCs without inducing apoptosis, and EPO-MSC treatment significantly alleviated liver fibrosis in a carbon tetrachloride (CCl4) induced mouse liver fibrosis model. CONCLUSION: EPO-MSCs enhance anti-fibrotic efficacy, with higher cell viability and stronger migration ability compared with treatment with BM-MSCs only. These findings support improving the efficiency of MSCs transplantation as a potential therapeutic strategy for liver fibrosis.

Phylogenetic and Morphological Identification of the Novel Pathogen of Rheum palmatum Leaf Spot in Gansu, China

( Yan Wang ),( Amy O. Charkowski ),( Cuiyun Zeng ),( Tiantian Zhu ),( Huizhen Wang ),( Honggang Chen ) 한국균학회 2016 Mycobiology Vol.44 No.2

A new leaf spot disease was observed on leaves of Rheum palmatum (Chinese rhubarb) in Northwest China (Gansu Province) starting in 2005. A Septoria-like fungus was isolated and completion of Koch’s postulates confirmed that the fungus was the casual agent of the leaf spot disease. Morphology and molecular methods were combined to identify the pathogen. The fungus produced conidiomata pycnidia and the conidia were 2~5 septate, 61.2~134.1 μm in length and 3.53~5.3 μm in width, which is much larger than the known Spetoria species that infects Polygonaceae species. Phylogenic analysis of the internal transcribed spacer region confirmed that this Septoria-like fungus is within the Septoria genus but distinct from known Septoria species. Together, these morphological and phylogenetic data support that the R. palmatum infecting Septoria strain is a newlydescribed plant pathogenic species.

Position and speed estimation for high speed permanent magnet synchronous motors using wideband synchronous fundamental‑frequency extraction filters

Jie Song,Huizhen Wang,Chunjuan Zhang,Weifeng Liu,Yirong Shen 전력전자학회 2022 JOURNAL OF POWER ELECTRONICS Vol.22 No.2

The non-ideal factors such as the inherent chattering of a sliding mode observer (SMO), the delay of a control algorithm, and the dead-time effect give rise to the harmonic error of position estimation. To improve the performance of the position observation of high-speed permanent magnet synchronous motors (HSPMSMs), a wideband synchronous fundamentalfrequency extraction filter (WSFEF) is proposed. On this basis, a novel signal processing method consisting of a WSFEF-PLL is applied to extract the fundamental frequency signal of the estimated back electromotive force (EMF). The application of a phase-locked loop (PLL) ensures that the resonance frequency of the WSFEF is adaptive, which is essential for the variablespeed operation in sensorless HSPMSM drive systems. Using the WSFEF-PLL in a SMO-based position estimator, the rotor position estimation error caused by the harmonics contained in the back EMF can be effectively eliminated, which contributes to improving the accuracy and dynamic performance of the rotor position estimation. Simulations and experiments verify the feasibility and effectiveness of this method.

A Novel Zero-Voltage-Switching Push-Pull DC-DC Converter for High Input Voltage and High Power Applications

Saijun Mao,Huizhen Wang,Yangguang Yon 대한전기학회 2005 KIEE International Transactions on Electrical Mach Vol.5-B No.4

A Novel Zero-Voltage-Switching Push-Pull DC-DC Converter for High Input Voltage and High Power Applications

Mao Saijun,Wang Huizhen,Yan Yangguang The Korean Institute of Electrical Engineers 2005 KIEE International Transactions on Electrical Mach Vol.b5 No.4

This paper proposes a novel zero-voltage-switching (ZVS) Push-pull DC-DC Converter for high input voltage and high power applications. This topology utilizes two switches in series to replace one switch in conventional push-pull converter, and two clamping diodes are introduced. The voltage stress of the switches is the input voltage, and the switches can realize ZVS with the use of the leakage inductance of the transformer. Furthermore, secondary full-wave rectifier with a clamping capacitor is used to eliminate the voltage oscillation and spike of the rectifier diodes due to the reverse recovery. Therefore, the electromagnetic interference is reduced effectively. The operation principle of the proposed converter is analyzed theoretically. The output characteristic, ZVS condition and design principle of the clamping capacitor are discussed. Experimental results obtained from a 270V input 2kW prototype with $95.8\%$ high efficiency confirms the design.

Contrast-Enhanced Harmonic Ultrasonography for the Assessment of Prostate Cancer Aggressiveness: a Preliminary Study

Yunkai Zhu,Yaqing Chen,Jun Jiang,Ren Wang,Yongchang Zhou,Huizhen Zhang 대한영상의학회 2010 Korean Journal of Radiology Vol.11 No.1

Objective: To determine whether contrast-enhanced harmonic ultrasonography can be used to predict the aggressiveness of prostate cancer. Materials and Methods: Contrast-enhanced harmonic ultrasonography was performed in 103 patients suspected of prostate cancer before biopsy. Time intensity curves were reconstructed for systematic biopsy sites and sonographic abnormalities. The characteristics of the curves were described using hemodynamic indices including arrival time (AT), time-to-peak (TTP), and peak intensity (PI). The differences of hemodynamic indices between high-grade and low-grade cancer were analyzed and the correlations between the hemodynamic indices and biopsy Gleason score were studied. Results: Prostate cancer was detected in 41 of 103 patients and there were significant differences in the hemodynamic indices between the biopsy sites of the non-malignant patients and prostate cancer lesions (p < 0.05). The prostate biopsies revealed 154 prostate cancer lesions, including 31 low-grade lesions and 123 high-grade lesions. The hemodynamic indices AT and TTP of highgrade tumors were significantly shorter than those of low-grade tumors (p = 0.001, 0.002). In addition, high-grade peripheral zone (PZ) tumors had higher PI than low-grade PZ tumors (p = 0.009). The PZ prostate cancer Gleason score correlated with PI, AT and TTP, with Spearman correlation coefficients of 0.223, -0.335, and -0.351, respectively (p = 0.013, < 0.001 and < 0.001). Conclusion: Contrast-enhanced ultrasound measurements of hemodynamic indices correlate with the prostate cancer Gleason score. Objective: To determine whether contrast-enhanced harmonic ultrasonography can be used to predict the aggressiveness of prostate cancer. Materials and Methods: Contrast-enhanced harmonic ultrasonography was performed in 103 patients suspected of prostate cancer before biopsy. Time intensity curves were reconstructed for systematic biopsy sites and sonographic abnormalities. The characteristics of the curves were described using hemodynamic indices including arrival time (AT), time-to-peak (TTP), and peak intensity (PI). The differences of hemodynamic indices between high-grade and low-grade cancer were analyzed and the correlations between the hemodynamic indices and biopsy Gleason score were studied. Results: Prostate cancer was detected in 41 of 103 patients and there were significant differences in the hemodynamic indices between the biopsy sites of the non-malignant patients and prostate cancer lesions (p < 0.05). The prostate biopsies revealed 154 prostate cancer lesions, including 31 low-grade lesions and 123 high-grade lesions. The hemodynamic indices AT and TTP of highgrade tumors were significantly shorter than those of low-grade tumors (p = 0.001, 0.002). In addition, high-grade peripheral zone (PZ) tumors had higher PI than low-grade PZ tumors (p = 0.009). The PZ prostate cancer Gleason score correlated with PI, AT and TTP, with Spearman correlation coefficients of 0.223, -0.335, and -0.351, respectively (p = 0.013, < 0.001 and < 0.001). Conclusion: Contrast-enhanced ultrasound measurements of hemodynamic indices correlate with the prostate cancer Gleason score.