Comprehensive CM Filter Design to Suppress Conducted EMI for SiC-JFET Motor Drives

Xun Gong,Ivan Josifovic,J.A. Ferreira 전력전자학회 2011 ICPE(ISPE)논문집 Vol.2011 No.5

This paper proposes a comprehensive EMI common-mode (CM) filter design procedure to suppress conducted EMI in silicon carbide (SiC) JFETs based inverter-fed motor drive systems. The first part of this paper is focusing on analyzing the EMC issue arisen from the newly generated power semiconductor device - SiC JFET, where the switching dynamics of SiC JFET and Si IGBT with the same power flowing level are compared. Then the second part towards EMI suppression for the inverter prototype. A comprehensive EMI CM filter design procedure is proposed. The proposed CM equivalent circuit model is able to evaluate the filter insertion loss gains over the whole conducted EMI frequency range, thereby different filter topologies can be compared and optimally selected. The performed experiments form the guideline that exhibits the process how the generated conducted EMI from the built inverter prototype is successfully suppressed to comply with the IEC61800-3 standard step by step.

Cutter-workpiece engagement determination for general milling using triangle mesh modeling

Gong, Xun,Feng, Hsi-Yung Society for Computational Design and Engineering 2016 Journal of computational design and engineering Vol.3 No.2

Cutter-workpiece engagement (CWE) is the instantaneous contact geometry between the cutter and the in-process workpiece during machining. It plays an important role in machining process simulation and directly affects the calculation of the predicted cutting forces and torques. The difficulty and challenge of CWE determination come from the complexity due to the changing geometry of in-process workpiece and the curved tool path of cutter movement, especially for multi-axis milling. This paper presents a new method to determine the CWE for general milling processes. To fulfill the requirement of generality, which means for any cutter type, any in-process workpiece shape, and any tool path even with self-intersections, all the associated geometries are to be modeled as triangle meshes. The involved triangle-to-triangle intersection calculations are carried out by an effective method in order to realize the multiple subtraction Boolean operations between the tool and the workpiece mesh models and to determine the CWE. The presented method has been validated by a series of case studies of increasing machining complexity to demonstrate its applicability to general milling processes.

Insights on the Cultivation of Mathematical Genius

( Gong Meiyong ),( Li Xun ) 한국수학교육학회 2013 수학교육 학술지 Vol.2013 No.-

Great emphasis should be laid on the cause and effect, the ins and outs of knowledge production in mathematics learning. For gifted students, we recommend extracurricular reading materials and videos etc. for their self-study under appropriate instructions. Meanwhile, different kinds of mathematics lectures or mathematics-related activities conducted in various levels serve as opportunities for them to communicate with others so as to enrich their knowledge and to raise their learning interest. Meanwhile, various sorts of platforms to demonstrate their talent will also be offered to help the students gain the sense of fulfillment, and to further stimulate their learning interest.

Berberine Prevents Intestinal Mucosal Barrier Damage During Early Phase of Sepsis in Rat through the Toll-Like Receptors Signaling Pathway

Guo-xun Li,Xi-mo Wang,Tao Jiang,Jian-feng Gong,Ling-ying Niu,Ning Li 대한생리학회-대한약리학회 2015 The Korean Journal of Physiology & Pharmacology Vol.19 No.1

Our previous study has shown berberine prevents damage to the intestinal mucosal barrier during early phase of sepsis in rat through mechanisms independent of the NOD-like receptors signaling pathway. In this study, we explored the regulatory effects of berberine on Toll-like receptors during the intestinal mucosal damaging process in rats. Male Sprague-Dawlay (SD) rats were treated with berberine for 5 d before undergoing cecal ligation and puncture (CLP) to induce polymicrobial sepsis. The expression of Toll-like receptor 2 (TLR 2), TLR 4, TLR 9, the activity of nuclear factor-kappa B (NF-κB), the levels of selected cytokines and chemokines, percentage of cell death in intestinal epithelial cells, and mucosal permeability were investigated at 0, 2, 6, 12 and 24 h after CLP. Results showed that the tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) level were significantly lower in berberine-treated rats compared to the control animals. Conversely, the expression level of tight junction proteins, percentage of cell death in intestinal epithelial cells and the mucosal permeability were significantly higher in berberine-treated rats. The mRNA expression of TLR 2, TLR 4, and TLR 9 were significantly affected by berberine treatment. Our results indicate that pretreatment with berberine attenuates tissue injury and protects the intestinal mucosal barrier in early phase of sepsis and this may possibly have been mediated through the TLRs pathway.

Elevated expression of WSB2 degrades p53 and activates the IGFBP3-AKT-mTOR-dependent pathway to drive hepatocellular carcinoma

Li Xun,Zhang Cheng-Cheng,Lin Xiao-Tong,Zhang Jie,Zhang Yu-Jun,Yu Hong-Qiang,Liu Ze-Yu,Gong Yi,Zhang Lei-Da,Xie Chuan-Ming 생화학분자생물학회 2024 Experimental and molecular medicine Vol.56 No.-

Dysregulation of wild-type p53 turnover is a key cause of hepatocellular carcinoma (HCC), yet its mechanism remains poorly understood. Here, we report that WD repeat and SOCS box containing protein 2 (WSB2), an E3 ubiquitin ligase, is an independent adverse prognostic factor in HCC patients. WSB2 drives HCC tumorigenesis and lung metastasis in vitro and in vivo. Mechanistically, WSB2 is a new p53 destabilizer that promotes K48-linked p53 polyubiquitination at the Lys291 and Lys292 sites in HCC cells, leading to p53 proteasomal degradation. Degradation of p53 causes IGFBP3-dependent AKT/mTOR signaling activation. Furthermore, WSB2 was found to bind to the p53 tetramerization domain via its SOCS box domain. Targeting mTOR with everolimus, an oral drug, significantly blocked WSB2-triggered HCC tumorigenesis and metastasis in vivo. In clinical samples, high expression of WSB2 was associated with low wild-type p53 expression and high p-mTOR expression. These findings demonstrate that WSB2 is overexpressed and degrades wild-type p53 and then activates the IGFBP3-AKT/mTOR axis, leading to HCC tumorigenesis and lung metastasis, which indicates that targeting mTOR could be a new therapeutic strategy for HCC patients with high WSB2 expression and wild-type p53.

Berberine Prevents Intestinal Mucosal Barrier Damage During Early Phase of Sepsis in Rat through the Toll-Like Receptors Signaling Pathway

Li, Guo-Xun,Wang, Xi-Mo,Jiang, Tao,Gong, Jian-Feng,Niu, Ling-Ying,Li, Ning The Korean Society of Pharmacology 2015 The Korean Journal of Physiology & Pharmacology Vol.19 No.1

Our previous study has shown berberine prevents damage to the intestinal mucosal barrier during early phase of sepsis in rat through mechanisms independent of the NOD-like receptors signaling pathway. In this study, we explored the regulatory effects of berberine on Toll-like receptors during the intestinal mucosal damaging process in rats. Male Sprague-Dawlay (SD) rats were treated with berberine for 5 d before undergoing cecal ligation and puncture (CLP) to induce polymicrobial sepsis. The expression of Toll-like receptor 2 (TLR 2), TLR 4, TLR 9, the activity of nuclear factor-kappa B ($NF-{\kappa}B$), the levels of selected cytokines and chemokines, percentage of cell death in intestinal epithelial cells, and mucosal permeability were investigated at 0, 2, 6, 12 and 24 h after CLP. Results showed that the tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$) and interleukin-6 (IL-6) level were significantly lower in berberine-treated rats compared to the control animals. Conversely, the expression level of tight junction proteins, percentage of cell death in intestinal epithelial cells and the mucosal permeability were significantly higher in berberine-treated rats. The mRNA expression of TLR 2, TLR 4, and TLR 9 were significantly affected by berberine treatment. Our results indicate that pretreatment with berberine attenuates tissue injury and protects the intestinal mucosal barrier in early phase of sepsis and this may possibly have been mediated through the TLRs pathway.

Synthesis, Characterization and In Vitro Evaluation of Triptolide-lysozyme Conjugate for Renal Targeting Delivery of Triptolide

Zheng, Qiang,Gong, Tao,Sun, Xun,Zhang, Zhi-Rong The Pharmaceutical Society of Korea 2006 Archives of Pharmacal Research Vol.29 No.12

A triptolide-lysozyme (TP-LZM) conjugate was synthesized to achieve renal specific delivery and to reduce the side effects of triptolide. Triptolide was coupled to lysozyme through succinic via an ester bond with an average coupling degree of 1 mol triptolide per 1 mol lysozyme. The lysozyme can specifically accumulate in the proximal tubular cells of the kidney, making it a potential carrier for targeting drugs to the kidney. The structure of triptolide succinate (TPS) was confirmed by IR, $^{1}H-NMR$, MS and UV. The concentrations of triptolide in various samples were determined by reversed-phase high-performance liquid chromatography (HPLC). In this study, the physicochemical and stability profiles of TP-LZM under various conditions were investgated the stability and releasing profiles of triptolide-lysozyme (TP-LZM) under various conditions. In vitro release trails showed triptolide-lysozyme was relatively stable in plasma (less than 30% of free triptolide released) and could release triptolide quickly in lysosome (more than 80% of free triptolide released) at $37^{\circ}C$ for 24 h. In addition, the biological activities of the conjugate on normal rat kidney proximal tubular cells (NRK52E) were also tested. The conjugate can effectively reduce NO production in the medium of NRK52E induced by lipopolysaccharide (LPS) but with much lower toxicity. These studies suggest the possibility to promote curative effect and reduce its extra-renal toxicity of triptolide by TP-LZM conjugate.

Synthesis and negative inotropic effects evaluation of 7-substituted-4,5-dihydro-[1,2,4]oxadiazolo[4,3-a]quinolin- 1-ones

Lan Hong,Guo-Hua Gong,Li Yu,Ming-Xia Song,Xun Cui,Zhe-Shan Quan 대한약학회 2013 Archives of Pharmacal Research Vol.36 No.11

A series of 7-alkoxy-4,5-dihydro-[1,2,4]oxadiazolo[4,3-a]quinolin-1-ones was synthesized and theirnegative inotropic effects were evaluated by measuring theleft atrium stroke volume in isolated rabbit heart preparations. All compounds moderated the cardiac workload bydecreasing heart rate and contractility (inotropic effects). Among them, compound 6 was found to be best potent witha -28.89 ± 1.91 % decrease in the stroke volume at aconcentration of 3 9 10-5 M in our in vitro study.

Synthesis, Characterization and In Vitro Evaluation of Triptolide-lysozyme Conjugate for Renal Targeting Delivery of Triptolide

Qiang Zheng,Tao Gong,Xun Sun,Zhi-Rong Zhang 대한약학회 2006 Archives of Pharmacal Research Vol.29 No.12

A triptolide-lysozyme (TP-LZM) conjugate was synthesized to achieve renal specific delivery and to reduce the side effects of triptolide. Triptolide was coupled to lysozyme through succinic via an ester bond with an average coupling degree of 1 mol triptolide per 1 mol lysozyme. The lysozyme can specifically accumulate in the proximal tubular cells of the kidney, making it a potential carrier for targeting drugs to the kidney. The structure of triptolide succinate (TPS) was confirmed by IR, 1H-NMR, MS and UV. The concentrations of triptolide in various samples were determined by reversed-phase high-performance liquid chromatography (HPLC). In this study, the physicochemical and stability profiles of TP-LZM under various conditions were investgated the stability and releasing profiles of triptolide-lysozyme (TP-LZM) under various conditions. In vitro release trails showed triptolide-lysozyme was relatively stable in plasma (less than 30 % of free triptolide released) and could release triptolide quickly in lysosome (more than 80 % of free triptolide released) at 37oC for 24 h. In addition, the biological activities of the conjugate on normal rat kidney proximal tubular cells (NRK52E) were also tested. The conjugate can effectively reduce NO production in the medium of NRK52E induced by lipopolysaccharide (LPS) but with much lower toxicity. These studies suggest the possibility to promote curative effect and reduce its extra-renal toxicity of triptolide by TP-LZM conjugate.

Activation of the Unfolded Protein Response via Co-expression of the HAC1i Gene Enhances Expression of Recombinant Elastase in Pichia pastoris

Minghai Han,Weixian Wang,Jianli Zhou,Xun Gong,Cunbin Xu,Yinfeng Li,Qiang Li 한국생물공학회 2020 Biotechnology and Bioprocess Engineering Vol.25 No.2

The effects of activation of the unfolded protein response (UPR) via co-expression of the HAC1i gene on the production of the recombinant Pseudomonas aeruginosa elastase (rPAE) in Pichia pastoris GS115 were evaluated in this study. The results showed that expression of the HAC1i gene significantly increased the level of Kar2p (a hallmark of UPR activation) in P. pastoris GS115, demonstrating activation of the UPR. This gene did not affect the growth of yeast in the buffered glycerol-complex medium but stimulated its growth in the buffered methanolcomplex medium. Co-expression of the HAC1i gene enhanced the expression level of the heterogeneously Nglycosylated forms of rPAE, as the caseinolytic activity in the supernatant of the various glycoforms of rPAE expressed in P. pastoris GS115/HAC1 was increased 1.8—3.9-fold compared to that in the control strain P. pastoris GS115, respectively. The stimulating effects of co-expression of the gene on rPAE production were observed when 0.5, 1.0, and 2.0% methanol were added every 24 h, as the caseinolytic activity of supernatants of P. pastoris GS115/HAC1 expressing wild-type of rPAE was increased 3.3-, 1.9-, and 1.7-fold at the corresponding methanol concentration. Further, activation of UPR via co-expression of the HAC1i gene enhanced rPAE secretion in P. pastoris at 20, 24, and 28°C, as the caseinolytic activity of supernatants of P. pastoris GS115/HAC1 expressing wild-type rPAE was increased 2.3-, 2.1-, and 2.8-fold over the tested temperatures.