New ZVZCT Bidirectional DC-DC Converter Using Coupled Inductors

Wei Qian,Xi Zhang,Zhe Liu,Wenqiang Jin,Jochen Wiedemann 전력전자학회 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.1

In this study, a novel zero voltage zero current transition (ZVZCT) bidirectional DC-DC converter is proposed by employingcoupled inductors. This converter can turn the main switch on at ZVZCT and it can turn it off with zero voltage switching (ZVS)for both the boost and buck modes. These characteristics are obtained by using a simple auxiliary sub-circuit regardless of thepower flow direction. In the boost mode, the auxiliary switch achieves zero current switching (ZCS) turn-on and ZVS turn off. Due to the coupling inductors, this converter can make further efficiency improvements because the resonant energy in thecapacitor or inductor can be transferred to the load. The main diode operates with ZVT turn-on and ZCS turn-off in the boostmode. For the buck mode, there is a releasing circuit to conduct the currents generated by the magnetic flux leakage to the output. The auxiliary switch turns on with ZCS and it turns off with ZVT. The main diode also turns on with ZVT and turns off withZCS. The design method and operation principles of the converter are discussed. A 500 W experimental prototype has been builtand verified by experimental results.

New ZVZCT Bidirectional DC-DC Converter Using Coupled Inductors

Qian, Wei,Zhang, Xi,Li, Zhe,Jin, Wenqiang,Wiedemann, Jochen The Korean Institute of Power Electronics 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.1

In this study, a novel zero voltage zero current transition (ZVZCT) bidirectional DC-DC converter is proposed by employing coupled inductors. This converter can turn the main switch on at ZVZCT and it can turn it off with zero voltage switching (ZVS) for both the boost and buck modes. These characteristics are obtained by using a simple auxiliary sub-circuit regardless of the power flow direction. In the boost mode, the auxiliary switch achieves zero current switching (ZCS) turn-on and ZVS turn off. Due to the coupling inductors, this converter can make further efficiency improvements because the resonant energy in the capacitor or inductor can be transferred to the load. The main diode operates with ZVT turn-on and ZCS turn-off in the boost mode. For the buck mode, there is a releasing circuit to conduct the currents generated by the magnetic flux leakage to the output. The auxiliary switch turns on with ZCS and it turns off with ZVT. The main diode also turns on with ZVT and turns off with ZCS. The design method and operation principles of the converter are discussed. A 500 W experimental prototype has been built and verified by experimental results.

Analysis of synonymous codon usage bias in helicase gene from Autographa californica multiple nucleopolyhedrovirus

Hongju Wang,Tao Meng,Wenqiang Wei 한국유전학회 2018 Genes & Genomics Vol.40 No.7

The helicase gene of Autographa californica multiple nucleopolyhedrovirus (AcMNPV) is not only involved in viral DNA replication, but also plays a role in viral host range. To identify the codon usage bias of helicase of AcMNPV, the codon usage bias of helicase was especially studies in AcMNPV and 41 reference strains of baculoviruses by calculating the codon adaptation index (CAI), effective number of codon (ENc), relative synonymous codon usage (RSCU), and other indices. The helicase of baculovirus is less biased (mean ENc = 50.539 > 40; mean CAI = 0.246). AcMNPV helicase has a strong bias toward the synonymous codons with G and C at the third codon position (GC3s = 53.6%). The plot of GC3s against ENc values revealed that GC compositional constraints are the main factor that determines the codon usage bias of major of helicase. Several indicators supported that the codon usage pattern of helicase is mainly subject to mutation pressure. Analysis of variation in codon usage and amino acid composition indicated AcMNPV helicase shows the significant preference for one or more postulated codons for each amino acid. A cluster analysis based on RSCU values suggested that AcMNPV is evolutionarily closer to members of group I alphabaculovirus. Comparison of the codon usage pattern among E. coli, yeast, mouse, human and AcMNPV showed that yeast is a suitable expression system for AcMNPV helicase. AcMNPV helicase shows weak codon usage bias. This study may help in elucidating the functional mechanism of AcMNPV helicase and the evolution of baculovirus helicases.

High level of LncRNA MAPKAPK5-AS1 predicts poor prognosis and contributes to the malignant proliferation and EMT of non-small cell lung cancer via sponging miR-490-3p from HMGB2

Miao Jidong,Gao Yang,Guan Wenqiang,Yu Xiaolin,Wang Yong,Jiang Ping,Yang Lili,Xu Lun,You Wei 한국유전학회 2023 Genes & Genomics Vol.45 No.5

Background Patients with non-small cell lung cancer (NSCLC) show a low survival rate, owing to the lack of early diagnostic method and high invasiveness. Long non-coding RNA MAPKAPK5-AS1 that regulates tumor genesis and progression through multiple signals, is upregulated and involved in the growth and apoptosis in lung adenocarcinoma (LUAD). Objective To investigate whether MAPKAPK5-AS1 affected the malignant progression of NSCLC. Methods The levels of MAPKAPK5-AS1, miR-490-3p and HMGB2 in lung cancer were first analyzed through StarBase website, and confirmed by a quantitative reverse transcriptase-PCR (qRT-PCR) assay. The biological functions of NSCLC cells were examined by CCK-8, 5-ethynyl-2ʹ-deoxyuridine (EdU) and flow cytometry assays. The potential binding sequences lncRNA-miRNA and miRNA-mRNA were predicted by StarBase software and verified via dual luciferase reporter experiment. The effects of MAPKAPK5-AS1 on tumor growth were evaluated in a xenografted mice model. Results The expression of MAPKAPK5-AS1 was upregulated in tumor tissues from NSCLC patients. Patients with high expression of MAPKAPK5-AS1 had higher tumor size, advanced TNM stage, higher incidence of lymph node and distant metastasis, and shorter overall survival. Knockdown of MAPKAPK5-AS1 inhibited the proliferation, induced apoptosis and blocked epithelial mesenchymal transformation (EMT) of NSCLC cells. Mechanically, MAPKAPK5-AS1 could upregulate the HMGB2 level in NSCLC cells through competitively binding to miR-490-3p. MiR-490-3p inhibitor reversed the roles of MAPKAPK5-AS1 knockdown on tumor cell proliferation, apoptosis and EMT. Also, HMGB2 knockdown suppressed tumor cell malignant phenotypes. Furthermore, interference of MAPKAPK5-AS1 slowed NSCLC tumor growth in vivo. Conclusion Knockdown of MAPKAPK5-AS1 inhibited the aggressive tumor phenotypes through miR-490-3p/HMGB2 axis in NSCLC. MAPKAPK5-AS1/miR-490-3p/HMGB2 might be potential biomarkers or therapeutic targets for NSCLC.

A national survey on how to improve traditional Chinese medicine learning internationally: Perceptions from both teachers and students

Zhu Yu-Hang,Yan Wu,Hao Zhang,Yanfei Zhao,Yule Ren,Wei Hu,Pan Li,Huiyi Wang,Ying Wang,Boda Zhang,Yujie Wang,Hongwen Yuan,Jiping Zhang,Wenqiang Li,Yufang Zhao,Jie Zhao,Yedong Shi,Yanye Shu,Xiao Zhang,Ya 한국한의학연구원 2022 Integrative Medicine Research Vol.11 No.4

Background With the increasing popularity of traditional Chinese medicine (TCM) by the global community, how to teach basic knowledge of TCM to international students and improve the teaching quality are important issues for teachers of TCM. The present study was to analyze the perceptions from both students and teachers on how to improve TCM learning internationally. Methods A cross-sectional national survey was conducted at 23 universities/colleges across China. A structured, self-reported on-line questionnaire was administered to 34 Chinese teachers who taught TCM course in English and to 1016 international undergraduates who were enrolled in the TCM course in China between 2017 and 2021. Results Thirty-three (97.1%) teachers and 900 (88.6%) undergraduates agreed Chinese culture should be fully integrated into TCM courses. All teachers and 944 (92.9%) undergraduates thought that TCM had important significance in the clinical practice. All teachers and 995 (97.9%) undergraduates agreed that modern research of TCM is valuable. Thirty-three (97.1%) teachers and 959 (94.4%) undergraduates thought comparing traditional medicine in different countries with TCM can help the students better understand TCM. Thirty-two (94.1%) teachers and 962 (94.7%) undergraduates agreed on the use of practical teaching method with case reports. From the perceptions of the undergraduates, the top three beneficial learning styles were practice (34.3%), teacher's lectures (32.5%), case studies (10.4%). The first choice of learning mode was attending to face-to-face teaching (82.3%). The top three interesting contents were acupuncture (75.5%), Chinese herbal medicine (63.8%), and massage (55.0%). Conclusion To improve TCM learning among international undergraduates majoring in conventional medicine, integration of Chinese culture into TCM course, comparison of traditional medicine in different countries with TCM, application of the teaching method with case reports, and emphasization of clinical practice as well as modern research on TCM should be fully considered.