ORiginal Article : miR-197 Expression in Peripheral Blood Mononuclear Cells from Hepatitis B Virus-Infected Patients

( Li Chen ),( Cong Zhi Li ),( Zaiquan Peng ),( Jin Xiang Zhao ),( Guo Zhong Gong ),( De Ming Tan ) The Editorial Office of Gut and Liver 2013 Gut and Liver Vol.7 No.3

Background/Aims: This study aimed to investigate the microRNA (miRNA) expression profiles in peripheral blood mononuclear cell (PBMC) of hepatitis B virus (HBV)-infected patients with different clinical manifestations and to analyze the function of miR-197. Methods: PBMC miRNA expression profiles in 51 healthy controls, 70 chronic asymptomatic carriers, 107 chronic hepatitis B patients, and 76 HBV-related acute on chronic liver failure patients were analyzed by quantitative real-time polymerase chain reaction (qRT-PCR). miR-197 mimic and inhibitor were transfected in THP-1 cells. qRT PCR and ELISA for interleukin (IL)-18 mRNA and protein levels were performed, respectively. Results: The microarray analysis revealed that 17 PBMC miRNA expression profiles (12 miRNAs downregulated and five miRNAs upregulated) differed significantly in HBV-induced liver disease patients presenting with various symptoms. The qRT-PCR results suggested that the PBMC miR-197 levels regularly decreased as the severity of liver disease symptoms became aggravated. IL 18, a key regulator in inflammation and immunity, was inversely correlated with miR-197 levels. Bioinformatic analysis indicated that IL-18 was a target of miR-197. Exogenous expression of miR-197 could significantly repress IL 18 expression at both the mRNA and protein levels in THP-1 cells. Conclusions: We concluded that multiple PBMC miRNAs had differential expression profiles during HBV infection and that miR-197 may play an important role in the reactivation of liver inflammation by targeting IL-18. (Gut Liver 2013; 7:335-342)

Predictive control with optimal vector sequence for permanent magnet synchronous motors

Li, Chen,Shi, Ting-Na,Yan, Yan,Zhou, Zhan-Qing,Xia, Chang-Liang The Korean Institute of Power Electronics 2020 JOURNAL OF POWER ELECTRONICS Vol.20 No.2

Conventional model predictive control aims to minimize ripples of the torque, stator flux and current at the end instant of each control period. However, the trajectories of the torque and flux during the entire control period are changed when multiple voltage vectors are applied in different sequences in each period. This indicates that the ripples of the torque and stator flux are influenced by different vector sequences (i.e., the sequence multiple vectors applied in). For that issue, this paper analyzes the RMS values of the stator flux vector ripple when three basic vectors are applied in different five-segment sequences, and proposes a predictive control with optimal vector sequence method. Based on this analysis, the available vector sequences that reduce the stator flux vector ripple are screened out. Moreover, a cost function is constructed to select the optimal vector sequence by evaluating the stator flux ripple during the entire control period and the tracking error of the stator flux vector at the end instant of each control period. Finally, simulation and experimental results verify the effectiveness of the proposed method.

Formation and Oxidation of Nitrided layers formed on Titanium alloys by Gas Nitriding

Li Chen,I. Pohrelyuk,O. Yaskiv,O. Tkachuk,Dong-Bok Lee 한국표면공학회 2010 한국표면공학회 학술발표회 초록집 Vol.2010 No.5

As a result of the nitrogen interaction during gas nitriding, a titanium nitride layer was formed, followed by an interstitial solution of nitrogen in the hcp α-itanium. The phase composition at the outmost nitrided surface layer of Ti-6Al-4V alloy is TiN and Ti₂N. In the Ti-N compound layer, Ti₂N is the major phase and TiN is the minor one. Al exists as dissolved ions at the top surface of the Ti-N compound layer. Nanoindentation microhardness testing was conducted on the nitrided titanium alloys to analyze their hardness evolution in relation to the nitriding processing parameters and alloy composition. It was found that themicrohardness increases due to the strengthening effect of interstitial nitrogen and the formation of nitrides. When the nitrided Ti-6Al-4V titanium alloy was oxidized at 600℃ and 700℃ for 10 hrs in air, the nitrided alloys oxidized slightly. Above 800℃, they oxidized fast and microcracking developed on the nitride surface. The microhardness of the surface layers was very high, and it decreased through the diffusion zone to approach the base microhardness of the matrix. Nitriding and oxidation increased the surface microhardness due to the strengthening effect of interstitial nitrogen and oxygen as well as the formation of titanium-nitrides and -oxides. The microhardness of the nitrided alloys increased with the increase of the oxidizing temperature.

Mimicking the pattern formation of fruits and leaves using gel materials

Li Chen,Yang Zhang,Somsak Swaddiwudhipong,Zishun Liu 국제구조공학회 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.50 No.5

Gel materials have recently gained more attention due to its unique capability of large andreversible volumetric changes. This study explores the possibility of mimicking the pattern formation ofcertain natural fruits during their growing process and leaves during drying processes through the swellingand de-swelling of gel materials. This will hopefully provide certain technical explanations on themorphology of fruits and plants. We adopt the inhomogeneous field gel theory to predict the deformationconfigurations of gel structures to describe the morphology of natural fruits and plants. The growingprocesses of apple and capsicum are simulated by imposing appropriate boundary conditions and fieldloading via varying the chemical potential from their immature to mature stages. The drying processes ofthree types of leaves with different vein structures are also investigated. The simulations lead to promisingresults and demonstrate that pattern formation of fruits and plants may be described from mechanicalperspective by the behavior of gel materials based on the inhomogeneous field theory.

Hypoxia and angiogenesis: regulation of hypoxia-inducible factors via novel binding factors

Li Chen,Alexander Endler,Futoshi Shibasaki 생화학분자생물학회 2009 Experimental and molecular medicine Vol.41 No.12

The mechanisms that regulate angiogenesis in hypoxia or hypoxic microenvironment are modulated by several pro- and antiangiogenic factors. Hypoxia-inducible factors (HIFs) have been established as the basic and major inducers of angiogenesis, but understanding the role of interacting proteins is becoming increasingly important to elucidate the angiogenic processes of a hypoxic response. In particular, with regard to wound healing and the novel therapies for vascular disorders such as ischemic brain and heart attack, it is essential to gain insights in the formation and regulation of HIF transcriptional machineries related to angiogenesis. Further, identification of alternative ways of inhibiting tumor growth by disrupting the growth-triggering mechanisms of increasing vascular supply via angiogenesis depends on the knowledge of how tumor cells develop their own vasculature. Here, we review our findings on the interactions of basic HIFs, HIF-1α and HIF-2α, with their regulatory binding proteins, histone deacetylase 7 (HDAC7) and translation initiation factor 6 (Int6), respectively. The present results and discussion revealed new regulatory interactions of HIF-related mechanisms. The mechanisms that regulate angiogenesis in hypoxia or hypoxic microenvironment are modulated by several pro- and antiangiogenic factors. Hypoxia-inducible factors (HIFs) have been established as the basic and major inducers of angiogenesis, but understanding the role of interacting proteins is becoming increasingly important to elucidate the angiogenic processes of a hypoxic response. In particular, with regard to wound healing and the novel therapies for vascular disorders such as ischemic brain and heart attack, it is essential to gain insights in the formation and regulation of HIF transcriptional machineries related to angiogenesis. Further, identification of alternative ways of inhibiting tumor growth by disrupting the growth-triggering mechanisms of increasing vascular supply via angiogenesis depends on the knowledge of how tumor cells develop their own vasculature. Here, we review our findings on the interactions of basic HIFs, HIF-1α and HIF-2α, with their regulatory binding proteins, histone deacetylase 7 (HDAC7) and translation initiation factor 6 (Int6), respectively. The present results and discussion revealed new regulatory interactions of HIF-related mechanisms.

Advanced Gastric Carcinoma with Signet Ring Cell Histology

Li, Chen,Kim, Sungsoo,Lai, Ji Fu,Hyung, Woo Jin,Choi, Won Hyuk,Choi, Seung Ho,Noh, Sung Hoon S. Karger AG 2007 Oncology Vol.72 No.1

<P><I>Background:</I> Gastric signet ring cell carcinoma (SRC) is a histological type based on microscopic characteristics and not on biological behavior. This study compared the clinicopathological features and prognosis of advanced SRC with non-signet ring cell adenocarcinoma (NSRC) of the stomach. <I>Methods:</I> We reviewed the records of 4,759 consecutive patients diagnosed with advanced gastric adenocarcinoma who were resected surgically from 1987 to 2003. Of these, 662 patients (13.9%) had SRC and were compared with 4,097 patients with NSRC. <I>Results:</I> Significant differences were noted in tumor size, Borrmann type, depth of invasion, lymph node metastasis, peritoneal dissemination and TNM stage. The cumulative 5-year survival rate for advanced SRC was 42.4%, compared with 50.1% in NSRC (p<I> = </I>0.009). Multivariate analysis showed that tumor size ≥5 cm, Borrmann III and IV, T3-4 invasion and SRC histology were independent risk factors for lymph node metastasis. Depth of invasion, lymph node metastasis, hepatic and peritoneal metastasis and surgical curability were significant factors affecting survival. SRC histology alone was not an independent prognostic factor. <I>Conclusions:</I> Advanced gastric SRC tends toward deeper tumor invasion and more lymph node and peritoneal metastasis than NSRC. Advanced gastric SRC had a worse prognosis than NSRC. Therefore, curative surgical operation with extended lymph node dissection is recommended.</P><P>Copyright © 2007 S. Karger AG, Basel</P>

Mesoscopic study of the formation of pseudomorphs with presence of chemical fluids

Li Chen,Qinjun Kang,Hailin Deng,J. William Carey,WenQuan Tao 한국지질과학협의회 2014 Geosciences Journal Vol.18 No.4

A numerical approach is developed to simulate theformation of pseudomorphs with presence of chemical fluids at themesoscopic scale. This approach consists of the lattice Boltzmannmethod (LBM) for transport of chemical species in the pore space,a chemical reaction model including basic kinetics of the coupleddissolution and precipitation reactions, and a mesoscopic modelfor nucleation and crystal growth. Our study confirms the mechanismof the solution chemistry-driven interface-coupled dissolution-precipitation for the formation of pseudomorphs and identifiesseveral sources for the generation of porosity in the pseudomorphs. We demonstrate that epitaxial precipitation is not necessary andrandom crystal growth may be more favorable for pseudomorphs. We show that the difference of precipitation barrier on the surfaceof the primary and secondary minerals should not be too large. Otherwise only the rim of the primary phase is roughly preserved.

Risk Factors of Survival and Surgical Treatment for Advanced Gastric Cancer with Large Tumor Size

Li, Chen,Oh, Sung Jin,Kim, Sungsoo,Hyung, Woo Jin,Yan, Min,Zhu, Zheng Gang,Noh, Sung Hoon Springer-Verlag 2009 Journal of gastrointestinal surgery Vol.13 No.5

Analytical calculation method for the axial equivalent elastic modulus of laminated FRP pipes based on three-dimensional stress state

Li Chen,Darong Pan,Qilin Zhao,Li-Cheng-Xi Huang,Liang Chen,Wei Xu 국제구조공학회 2021 Structural Engineering and Mechanics, An Int'l Jou Vol.77 No.1

In engineering design, the axial equivalent elastic modulus of laminated FRP pipe was mostly calculated by the average elastic modulus method or the classical laminated plate theory method, which are based on relatively simplified assumptions, and may be not accurate enough sometimes. A new analytical calculation method for the axial equivalent elastic modulus of laminated FRP pipe was established based on three-dimensional stress state. By comparing the results calculated by this method with those by the above two traditional analytical methods and the finite element method, it is found that this method for the axial equivalent elastic modulus fits well not only for thin-walled pipes with orthotropic layers, but also for thick-walled pipes with arbitrary layers. Besides, the influence of the layer stacking on the axial equivalent elastic modulus was studied with this method. It is found that a proper content of circumferential layer is beneficial for improving the axial equivalent elastic modulus of the laminated FRP pipe with oblique layers, and then can reduce its material quantity under the premise that its axial stiffness remains unchanged. Finally, the meso-mechanical mechanism of this effect was analyzed. The improving effect of circumferential layer on the axial equivalent elastic modulus of the laminated FRP pipe with oblique layers is mainly because that, the circumferential fibers can restrain the rigid body rotations of the oblique fibers, which tend to cause the significant deformations of the pipe wall units and the relatively low axial equivalent elastic modulus of the pipe.

Performance Analysis of Multi-antennas Combining and Selection Schemes for Wireless-Powered Communication

Li Chen,Xiaohui Chen,Weidong Wang,Chi Zhang 한국통신학회 2017 Journal of communications and networks Vol.19 No.2

We propose and analyze spatial diversity combining andselection schemes in a wireless-powered communication networkwith multi-antennas at energy access point (EAP) and data accesspoint (DAP). The EAP adopts either maximal-ratio transmittingor transmit antenna selection to wirelessly transfer power, and theDAP employs either maximal-ratio combining or receive antennaselection to combine the received information. It generates fourschemes for the wireless-powered communication network. We derivenew closed-form expressions for the statistical characterizationsof the received signal to noise ratio (SNR). Based on these expressions,the outage probability and the average throughput arefurther derived. The diversity order of the proposed schemes isgiven through the asymptotic outage probability analysis at highSNR regime. Nakagami-m fading with non-identical fading parametersis assumed for both power transfer channel and informationtransmission channel. Numerical results are given to validateall the analytical results. The impact of EAP transmit power, thenumber of EAP/DAP antennas, and the energy harvesting time onthe performance of the proposed schemes is also investigated. algorithm. The pro-posed non-greedy puncturing algorithm lies mainly in the dynam-ical minimization of the number of unpunctured variable nodes inthe redefined recovery tree for the punctured variable nodes. Fi-nally, simulation results show that the proposed puncturing algo-rithm outperforms the existing best puncturing algorithms in biterror rate performances of iterative decoding.