p‐Type InP Nanopillar Photocathodes for Efficient Solar‐Driven Hydrogen Production

Lee, Min Hyung,Takei, Kuniharu,Zhang, Junjun,Kapadia, Rehan,Zheng, Maxwell,Chen, Yu‐,Ze,Nah, Junghyo,Matthews, Tyler S.,Chueh, Yu‐,Lun,Ager, Joel W.,Javey, Ali WILEY‐VCH Verlag 2012 Angewandte Chemie Vol.124 No.43

<P><B>Perfekte Textur</B>: Der Einfluss der Oberflächen‐Nanotexturierung, der TiO<SUB>2</SUB>‐Passivierung und des Ru‐Cokatalysators auf die photoelektrochemische Wasserstoffentwicklung durch p‐InP‐Photokathoden wurde untersucht. Höhere Stromdichten und günstigere Onset‐Potentiale werden nach Oberflächen‐Nanotexturierung beobachtet. NHE=Normalwasserstoffelektrode.</P>

miR-340 Reverses Cisplatin Resistance of Hepatocellular Carcinoma Cell Lines by Targeting Nrf2-dependent Antioxidant Pathway

Shi, Liang,Chen, Zhan-Guo,Wu, Li-li,Zheng, Jian-Jian,Yang, Jian-Rong,Chen, Xiao-Fei,Chen, Zeng-Qiang,Liu, Cun-Li,Chi, Sheng-Ying,Zheng, Jia-Ying,Huang, Hai-Xia,Lin, Xiang-Yang,Zheng, Fang Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.23

Many chemotherapeutic agents have been successfully used to treat hepatocellular carcinoma (HCC); however, the development of chemoresistance in liver cancer cells usually results in a relapse and worsening of prognosis. It has been demonstrated that DNA methylation and histone modification play crucial roles in chemotherapy resistance. Currently, extensive research has shown that there is another potential mechanism of gene expression control, which is mediated through the function of short noncoding RNAs, especially for microRNAs (miRNAs), but little is known about their roles in cancer cell drug resistance. In present study, by taking advantage of miRNA effects on the resistance of human hepatocellular carcinoma cells line to cisplatin, it has been demonstrated that miR-340 were significantly downregulated whereas Nrf2 was upregulated in HepG2/CDDP (cisplatin) cells, compared with parental HepG2 cells. Bioinformatics analysis and luciferase assays of Nrf2-3'-untranslated region-based reporter constructor indicated that Nrf2 was the direct target gene of miR-340, miR-340 mimics suppressing Nrf2-dependent antioxidant pathway and enhancing the sensitivity of HepG2/CDDP cells to cisplatin. Interestingly, transfection with miR-340 mimics combined with miR-340 inhibitors reactivated the Nrf2 related pathway and restored the resistance of HepG2/CDDP cells to CDDP. Collectively, the results first suggested that lower expression of miR-340 is involved in the development of CDDP resistance in hepatocellular carcinoma cell line, at least partly due to regulating Nrf2-dependent antioxidant pathway.

Method Based on Sparse Signal Decomposition for Harmonic and Inter-harmonic Analysis of Power System

Chen, Lei,Zheng, Dezhong,Chen, Shuang,Han, Baoru The Korean Institute of Electrical Engineers 2017 Journal of Electrical Engineering & Technology Vol.12 No.2

Harmonic/inter-harmonic detection and analysis is an important issue in power system signal processing. This paper proposes a fast algorithm based on matching pursuit (MP) sparse signal decomposition, which can be employed to extract the harmonic or inter-harmonic components of a distorted electric voltage/current signal. In the MP iterations, the method extracts harmonic/inter-harmonic components in order according to the spectrum peak. The Fast Fourier Transform (FFT) and nonlinear optimization techniques are used in the decomposition to realize fast and accurate estimation of the parameters. First, the frequency estimation value corresponding to the maxim spectrum peak in the present residual is obtained, and the phase corresponding to this frequency is searched in discrete sinusoids dictionary. Then the frequency and phase estimations are taken as initial values of the unknown parameters for Nelder-Mead to acquire the optimized parameters. Finally, the duration time of the disturbance is determined by comparing the inner products, and the amplitude is achieved according to the matching expression of the harmonic or inter-harmonic. Simulations and actual signal tests are performed to illustrate the effectiveness and feasibility of the proposed method.

Intranasally Administered Adjunctive Dexmedetomidine Reduces Perioperative Anesthetic Requirements in General Anesthesia

Zheng Chen,Xiang Wu,Li-Hua Hang,Hong Wang,Dong-Hua Shao,Yi-Guo Xu,Wei Cui 연세대학교의과대학 2016 Yonsei medical journal Vol.57 No.4

Purpose: Intranasal dexmedetomidine is an effective sedative for premedication and is regularly used to reduce preoperative tension and anxiety in children. This study aimed to assess the effect of intranasally adjunctive dexmedetomidine on perioperativesedative and analgesic requirements in adults. Materials and Methods: Patients were randomly divided into four groups to receive preoperative administration of saline, intranasaldexmedetomidine 1 μg/kg and 2 μg/kg, and intravenous dexmedetomidine 1 μg/kg, respectively. Propofol and remifentanil were target-controlled infused to maintain intraoperative bispectral index at 45–55 and blood pressure at baseline value±20%. Sufentanil was administered to maintain postoperative visual analogue scale ≤3. Perioperative anesthetics requirements were compared using nonparametric tests. Results: Intranasal dexmedetomidine significantly attenuated propofol requirements for anesthesia induction and maintenance in a dose-dependent manner. Patients given intranasal dexmedetomidine 2 μg/kg required less remifentanil for anesthesia maintenance. The first postoperative request for sufentanil analgesia was delayed in patients given intranasal dexmedetomidine 2 μg/kg. The anesthetics-sparing effect of intranasal dexmedetomidine was significantly weaker than intravenous dexmedetomidine at the same dose of 1 μg/kg. The incidences of adverse events, including hemodynamic instability and delayed recovery, were comparablewith and without intranasal dexmedetomidine. Conclusion: Intranasal administration of dexmedetomidine can reduce perioperative anesthetic requirements, and a dose of dexmedetomidine 2 μg/kg produces a better effect in adults. The anesthetics-sparing effect of intranasal dexmedetomidine 1 μg/kg is less than that with the same intravenous dose of dexmedetomidine.

Instantaneous multi-mode identification and analysis of vortex-induced vibration via a mode decomposition method

Chen, Zheng-Shou,Rhee, Shin Hyung Elsevier 2019 Applied ocean research Vol.93 No.-

<P><B>Abstract</B></P> <P>The dynamic characteristics of marine risers/pipes often present serried modes with various frequencies due to high levels of structural flexibility and slenderness, especially when the flow velocity is non-uniformly distributed along the span. Therefore, the vortex-induced vibration (hence VIV) for slender risers/pipes is usually characterized by multi-mode motions. In this paper, by means of a newly developed empirical mode decomposition (EMD) method which contributes to more efficient instantaneous multi-mode identification and analysis, new characteristics of a multi-mode “lock-in” vibration process of a large-scale flexible pipe subject to shear flow were discussed. Because the two-degree vibration along the span can be analyzed simultaneously, the effects of multi-mode VIV were investigated systematically. From the given illustrative examples, it was found that the vibration energy diffusion between the fluid and the structure, and among the participating modes, may be repeatable and reversible, or even irreversible, which causes VIV to be highly intricate. The coexistence of multiple modes, energy transfer, and mode switching/jump is observed when the reduced velocity is relatively high. The multi-dominant mode phenomenon is also found in both cross-flow (CF) and in-line (IL) VIVs. Energy transfers between the CF and IL directions occasionally occur, and CF VIV is apt to dominate the vibration process, because it is superior to IL VIV with the increment of the reduced velocity.</P> <P><B>Highlights</B></P> <P> <UL> <LI> By means of a newly developed empirical mode decomposition (EMD) method, new characteristics of a multi-mode “lock-in” vibration process of a large-scale flexible pipe subject to shear flow were discussed. </LI> <LI> The vibration energy diffusion between the fluid and the structure, and among the participating modes, may be repeatable and reversible, or even irreversible, which causes VIV to be highly intricate. </LI> <LI> The multi-dominant mode phenomenon is found in both cross-flow (CF) and in-line (IL) VIVs. </LI> <LI> In contrast to IL VIV, CF VIV is superior and prone to dominate the vibration process with the increment of the reduced velocity. </LI> <LI> Energy transfers between the CF and IL directions occasionally occur. </LI> </UL> </P>

Empirical mode decomposition based on Fourier transform and band-pass filter

Zheng-Shou Chen,Shin Hyung Rhee,Gui-Lin Liu 대한조선학회 2019 International Journal of Naval Architecture and Oc Vol.11 No.2

A novel empirical mode decomposition strategy based on Fourier transform and band-pass filter techniques, contributing to efficient instantaneous vibration analyses, is developed in this study. Two key improvements are proposed. The first is associated with the adoption of a band-pass filter technique for intrinsic mode function sifting. The primary characteristic of decomposed components is that their bandwidths do not overlap in the frequency domain. The second improvement concerns an attempt to design narrowband constraints as the essential requirements for intrinsic mode function to make it physically meaningful. Because all decomposed components are generated with respect to their intrinsic narrow bandwidth and strict sifting from high to low frequencies successively, they are orthogonal to each other and are thus suitable for an instantaneous frequency analysis. The direct Hilbert spectrum is employed to illustrate the instantaneous time-frequency-energy distribution. Commendable agreement between the illustrations of the proposed direct Hilbert spectrum and the traditional Fourier spectrum was observed. This method provides robust identifications of vibration modes embedded in vibration processes, deemed to be an efficient means to obtain valuable instantaneous information.

Evaluation of CO₂ Fixing Ability of Cementitious Materials Containing γ-C₂S

Chen, Zheng Xin(진정심),Lee, Han Seung(이한승) 한국콘크리트학회 2019 한국콘크리트학회 학술대회 논문집 Vol.31 No.1

Study on the transient flow induced by the windbreak transition regions in a railway subject to crosswinds

Zheng-Wei Chen,Syeda Anam Hashmi,Tanghong Liu,Wenhui Li,Zhuang Sun,Dongrun Liu,Hassan Hemida,Hong-Kang Liu 한국풍공학회 2022 Wind and Structures, An International Journal (WAS Vol.35 No.5

Due to the complex terrain around high-speed railways, the windbreaks were established along different landforms, resulting in irregular windbreak transition regions between different subgrade infrastructures (flat ground, cutting, embankment, etc). In this paper, the effect of a windbreak transition on the wind flow around railways subjected to crosswinds was studied. Wind tunnel testing was conducted to study the wind speed change around a windbreak transition on flat ground with a uniform wind speed inflow, and the collected data were used to validate a numerical simulation based on a detached eddy simulation method. The validated numerical method was then used to investigate the effect of the windbreak transition from the flat ground to cutting (the “cutting” is a railway subgrade type formed by digging down from the original ground) for three different wind incidence angles of 90º, 75º, and 105º. The deterioration mechanism of the flow fields and the reasons behind the occurrence of the peak wind velocities were explained in detail. The results showed that for the windbreak transition on flat ground, the impact was small. For the transition from the flat ground to the cutting, the influence was relatively large. The significant increase in the wind speeds was due to the right-angle structure of the windbreak transition, which resulted in sudden changes of the wind velocity as well as the direction. In addition, the height mismatch in the transition region worsened the protective effect of a typical windbreak.

Primary Aldosteronism and Cerebrovascular Diseases

Zheng-Wei Chen,Chi-Sheng Hung,Vin-Cent Wu,Yen-Hung Lin,TAIPAI study group 대한내분비학회 2018 Endocrinology and metabolism Vol.33 No.4

As diagnostic techniques have advanced, primary aldosteronism (PA) has emerged as the most common cause of secondary hypertension. The excess of aldosterone caused by PA resulted in not only cardiovascular complications, including coronary artery disease,myocardial infarction, arrhythmia, and heart failure, but also cerebrovascular complications, such as stroke and transient ischemicattack. Moreover, PA is associated more closely with these conditions than is essential hypertension. In this review, we present up-todate findings on the association between PA and cerebrovascular diseases.

Grem1 accelerates nucleus pulposus cell apoptosis and intervertebral disc degeneration by inhibiting TGF-β-mediated Smad2/3 phosphorylation

Chen Shunlun,Lei Linchuan,Li Zemin,Chen Fan,Huang Yuming,Jiang Guowei,Guo Xingyu,Zhao Zhuoyang,Liu Hui,Wang Hua,Liu Caijun,Zheng Zhaomin,Wang Jianru 생화학분자생물학회 2022 Experimental and molecular medicine Vol.54 No.-

Intervertebral disc degeneration (IVDD) is a main cause of low back pain, and inflammatory factors play key roles in its pathogenesis. Gremlin-1 (Grem1) was reported to induce an inflammatory response in other fields. This study aimed to investigate the mechanisms of Grem1 in the degenerative process of intervertebral discs. Dysregulated genes were determined by analyzing microarray profiles. The expression of Grem1 in 17 human disc samples (male:female = 9:8) and rat models (n = 5 each group) was measured by western blotting (WB), real-time quantitative PCR (RT-qPCR), and immunohistochemistry (IHC). The regulatory effects of Grem1 on apoptosis were examined using siRNAs, flow cytometry, immunofluorescence (IF), and WB. The therapeutic effect was evaluated by locally injecting specific Grem1 siRNA into IVDD rats. The expression of Grem1 was significantly increased in human degenerative intervertebral discs; furthermore, the expression of Grem1 positively correlated with the level of intervertebral disc degeneration. Grem1 was significantly overexpressed in tumor necrosis factor (TNF)-α-induced degenerative NP cells. Apoptosis in degenerative NP cells transfected with siRNA targeting Grem1 was significantly lower than that in the control group. Specific Grem1 siRNA markedly repressed the development of IVDD in surgery-induced IVDD rats. These results indicated that the expression of Grem1 was positively correlated with the severity of intervertebral disc degeneration, and Grem1 siRNA could inhibit Grem1-induced apoptosis and extracellular matrix alterations by mediating the TGF-β/Smad signaling pathway. This study may provide a therapeutic strategy for alleviating inflammation-induced apoptosis associated with intervertebral disc degeneration.