miR-30c regulates proliferation, apoptosis and differentiation via the Shh signaling pathway in P19 cells

Xuehua Liu,Mengmeng Li,Yuzhu Peng,Xiaoshan Hu,Jing Xu,Shasha Zhu,Zhangbin Yu,Shuping Han 생화학분자생물학회 2016 Experimental and molecular medicine Vol.48 No.-

MicroRNAs (miRNAs) are small, non-coding single-stranded RNAs that suppress protein expression by binding to the 3′ untranslated regions of their target genes. Many studies have shown that miRNAs have important roles in congenital heart diseases (CHDs) by regulating gene expression and signaling pathways. We previously found that miR-30c was highly expressed in the heart tissues of aborted embryos with ventricular septal defects. Therefore, this study aimed to explore the effects of miR-30c in CHDs. miR-30c was overexpressed or knocked down in P19 cells, a myocardial cell model that is widely used to study cardiogenesis. We found that miR-30c overexpression not only increased cell proliferation by promoting cell entry into S phase but also suppressed cell apoptosis. In addition, we found that miR-30c inhibited dimethyl sulfoxide-induced differentiation of P19 cells. miR-30c knockdown, in contrast, inhibited cell proliferation and increased apoptosis and differentiation. The Sonic hedgehog (Shh) signaling pathway is essential for normal embryonic development. Western blotting and luciferase assays revealed that Gli2, a transcriptional factor that has essential roles in the Shh signaling pathway, was a potential target gene of miR-30c. Ptch1, another important player in the Shh signaling pathway and a transcriptional target of Gli2, was downregulated by miR-30c overexpression and upregulated by miR-30c knockdown. Collectively, our study revealed that miR-30c suppressed P19 cell differentiation by inhibiting the Shh signaling pathway and altered the balance between cell proliferation and apoptosis, which may result in embryonic cardiac malfunctions.

Facile Self-Assembly of Fe3O4 Nanoparticles@WS2 Nanosheets: A Promising Candidate for Supercapacitor Electrode

Yu Dai,Xiao Wu,Dawei Sha,Ming Chen,Han Zou,Jie Ren,Jingjing Wang,Xuehua Yan 대한금속·재료학회 2016 ELECTRONIC MATERIALS LETTERS Vol.12 No.6

Graphene-like dichalcogenides with huge surface area and nanostructuredtransition metal oxides with extraordinarily high theoretical capacities could becomposited as promising electrode candidates for supercapacitors. In this work,monolayer and few-layers WS2 nanosheets were exfoliated by combination ofball-milling and sonication. A facile strategy for the hierarchical self-assembly ofFe3O4 nanoparticles (Fe3O4NPs) on WS2 nanosheets was developed to synthesizeFe3O4NPs@WS2 nanocomposites via hydrothermal method. Fe3O4NPs areuniformly dispersed on the WS2 nanosheets without aggregation. The particlesize of Fe3O4NPs is about 3 nm. The nanocomposite shows strong enhancementsof electrochemical behaviors. This self-assembly synthesis strategy may havegreat prospects for other 0D/2D nanocomposites in supercapacitors and otherenergy devices.

Constant on‑time variable frequency control for critical conduction mode GaN‑based totem‑pole PFC converters

Shuang Zhang,Yu Fang,Kaixin Shu,Qiuyang Gu,Xuehua Wang 전력전자학회 2023 JOURNAL OF POWER ELECTRONICS Vol.23 No.12

A constant on-time variable frequency control (COTVFC) with feed-forward for a critical conduction mode (CRM) totempole power factor correction (PFC) converter is proposed in this paper. This control method only requires a single voltage loop, where the output is taken as the on-time of the main switches of the converter. The off-time of the main switches in different switching cycles is calculated by the voltage-second balance principle, which ensures that the converter always operates in the CRM. Feed-forward is introduced to improve the dynamic response of the converter. The control model is established and the transfer function from the on-time to the output is derived. On this basis, the control parameters of the voltage loop are designed. Then a simulation model is built in PSIM for simulation verification. Finally, a two-phase interleaved parallel GaN-based totem-pole PFC converter prototype is made for experimental verification. Simulation and experimental results verify the feasibility and effectiveness of the control method proposed in this paper.

A Hardware-in-the-loop Platform for Modular Multilevel Converter Simulations

Chongru Liu,Pengfei Tian,Yu Wang,Qi Guo,Xuehua Lin,Jiayu Wang 전력전자학회 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.5

In this paper, a hardware-in-the-loop simulation platform for MMCs is established, which connects a real time digital simulator (RTDS) and a designed MMC controller with optical fiber. In this platform, the converter valves are simulated with a small time step of 2.5 microsecond in the RTDS, and multicore technology is implemented for the controller so that the parallel valve control is distributed between different cores. Therefore, the designed controller can satisfy the requirements of real-time control. The functions of the designed platform and the rationality for the designed controller are verified through experimental tests. The results show that different modulation modes and various control strategies can be implemented in the simulation platform and that each control objective can been tracked accurately and with a fast dynamic response.

A Hardware-in-the-loop Platform for Modular Multilevel Converter Simulations

Liu, Chongru,Tian, Pengfei,Wang, Yu,Guo, Qi,Lin, Xuehua,Wang, Jiayu The Korean Institute of Power Electronics 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.5

In this paper, a hardware-in-the-loop simulation platform for MMCs is established, which connects a real time digital simulator (RTDS) and a designed MMC controller with optical fiber. In this platform, the converter valves are simulated with a small time step of 2.5 microsecond in the RTDS, and multicore technology is implemented for the controller so that the parallel valve control is distributed between different cores. Therefore, the designed controller can satisfy the requirements of real-time control. The functions of the designed platform and the rationality for the designed controller are verified through experimental tests. The results show that different modulation modes and various control strategies can be implemented in the simulation platform and that each control objective can been tracked accurately and with a fast dynamic response.

Dynamic behavior analysis of spur gears with constant & variable excitations considering sliding friction influence

Fuhao Liu,Hanjun Jiang,Shaona Liu,Xuehua Yu 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.12

A new analytical model of a spur gear system with sliding friction is presented. Unlike previous models, the excitation consists of two parts: the rotational driving speed of the pinion and the drag torque acting on the gear. The proposed model was validated with the finite element model. Using numerical method, the steady state resolutions was obtained to mainly demonstrate the nonlinear characteristics under both constant and variable excitations. The results obtained illustrate that sliding friction could introduce additional vibration. Moreover, the sliding friction even could decrease the dynamic transmission errors under proper operation condition. Further, the bifurcation diagram was plotted to show the influence of the rotational driving speed of the pinion on the dynamical characteristic of the gear system. Finally, the fluctuated excitation was used to exhibit their different effects on the gear system, which should form the basis of further analytical and experimental work in the gear dynamic area.

Glycoepitopes of Staphylococcal Wall Teichoic Acid Govern Complement-mediated Opsonophagocytosis via Human Serum Antibody and Mannose-binding Lectin

Kurokawa, Kenji,Jung, Dong-Jun,An, Jang-Hyun,Fuchs, Katharina,Jeon, Yu-Jin,Kim, Na-Hyang,Li, Xuehua,Tateishi, Koichiro,Park, Ji Ae,Xia, Guoqing,Matsushita, Misao,Takahashi, Kazue,Park, Hee-Ju,Peschel, American Society for Biochemistry and Molecular Bi 2013 The Journal of biological chemistry Vol.288 No.43

<P>Serum antibodies and mannose-binding lectin (MBL) are important host defense factors for host adaptive and innate immunity, respectively. Antibodies and MBL also initiate the classical and lectin complement pathways, respectively, leading to opsonophagocytosis. We have shown previously that <I>Staphylococcus aureus</I> wall teichoic acid (WTA), a cell wall glycopolymer consisting of ribitol phosphate substituted with α- or β-<I>O-N</I>-acetyl-<SMALL>d</SMALL>-glucosamine (GlcNAc) and <SMALL>d</SMALL>-alanine, is recognized by MBL and serum anti-WTA IgG. However, the exact antigenic determinants to which anti-WTA antibodies or MBL bind have not been determined. To answer this question, several <I>S. aureus</I> mutants, such as α-GlcNAc glycosyltransferase-deficient <I>S. aureus</I> Δ<I>tarM</I>, β-GlcNAc glycosyltransferase-deficient Δ<I>tarS</I>, and Δ<I>tarMS</I> double mutant cells, were prepared from a laboratory and a community-associated methicillin-resistant <I>S. aureus</I> strain. Here, we describe the unexpected finding that β-GlcNAc WTA-deficient Δ<I>tarS</I> mutant cells (which have intact α-GlcNAc) escape from anti-WTA antibody-mediated opsonophagocytosis, whereas α-GlcNAc WTA-deficient Δ<I>tarM</I> mutant cells (which have intact β-GlcNAc) are efficiently engulfed by human leukocytes via anti-WTA IgG. Likewise, MBL binding in <I>S. aureus</I> cells was lost in the Δ<I>tarMS</I> double mutant but not in either single mutant. When we determined the serum concentrations of the anti-α- or anti-β-GlcNAc-specific WTA IgGs, anti-β-GlcNAc WTA-IgG was dominant in pooled human IgG fractions and in the intact sera of healthy adults and infants. These data demonstrate the importance of the WTA sugar conformation for human innate and adaptive immunity against <I>S. aureus</I> infection.</P>