Effect of oxidizing treatment on electrocatalytic activity of boron‑doped amorphous carbon thin films

Chen‑Song Wang,Ni Suo,Hao Huang,Ai‑min Wu,Guo‑Zhong Cao,Gui‑Feng Zhang 한국탄소학회 2019 Carbon Letters Vol.29 No.5

Boron-doped amorphous carbon (BDAC) thin films with a regular oxygen reduction reaction (ORR) catalytic activity were synthesized in a hot filament chemical vapor deposition device using a mixture of CH4 and H2 as a gas source and B2O3 as a boron source and then oxidized in air at 380–470 °C for 15–75 min. Scanning electron microscope, transmission electron microscope, Raman spectroscopy, X-ray photoelectron spectroscopy, and electrochemical tests were used to characterize the physical and electrochemical properties of the BDAC catalysts. It was concluded that the BDAC catalyst oxidized at 450 °C for 45 min showed the best ORR catalytic activity in alkaline medium. The oxygen reduction potential and the transfer electron number n, respectively, are − 0.286 V versus Ag/AgCl and 3.24 from the rotating disk electrode experiments. The treated carbon film has better methanol resistance and stability than the commercial Pt/C catalyst.

Discovery of Anticostia uniformis from the Xiazhen Formation at Zhuzhai, South China and its stratigraphic implication

Chen, Zhong-Yang,Kim, Myong-Hak,Choh, Suk-Joo,Lee, Dong-Jin,Chen, Xu Elsevier 2016 Palaeoworld Vol.25 No.3

<P>The Xiazhen Formation is an Upper Ordovician lithostratigraphic unit in the Jiangshan-Changshan-Yushan (JCY) area, which contains series of Late Ordovician reef successions. The reef successions of the Xiazhen Formation at Zhuzhai are critical for evaluation of the Late Ordovician marine diversity and palaeoecology. However, their age has long been uncertain and generally is regarded as of upper Katian, based on the occurrences of shelly fossils and correlation with the stratigraphic equivalent Changwu Formation. The newly discovered graptolite species Anticostia uniformis, in the Xiazhen Formation, together with the combined evidence of brachiopods and sedimentology, indicates an age range for the graptolite locality from the Dicellograptus complanatus Biozone to the Diceratograptus mirus Subzone of late Katian, but the graptolites do not rule out the possibility that it is Hirnantian. (C) 2015 Elsevier B.V. and Nanjing Institute of Geology and Palaeontology, CAS. All rights reserved.</P>

EMI Noise Source Reduction of Single-Ended Isolated Converters Using Secondary Resonance Technique

Chen, Zhangyong,Chen, Yong,Chen, Qiang,Jiang, Wei,Zhong, Rongqiang The Korean Institute of Power Electronics 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.2

Aiming at the problems of large dv/dt and di/dt in traditional single-ended converters and high electromagnetic interference (EMI) noise levels, a single-ended isolated converter using the secondary resonance technique is proposed in this paper. In the proposed converter, the voltage stress of the main power switch can be reduced and the voltage across the output diode is clamped to the output voltage when compared to the conventional flyback converter. In addition, the peak current stress through the main power switch can be decreased and zero current switching (ZCS) of the output diode can be achieved through the resonance technique. Moreover, the EMI noise coupling path and an equivalent model of the proposed converter topology are presented through the operational principle of the proposed converter. Analysis results indicate that the common mode (CM) EMI noise and the differential mode (DM) EMI noise of such a converter are deduced since the frequency spectra of the equivalent controlled voltage sources and controlled current source are decreased when compared with the traditional flyback converter. Furthermore, appropriate parameter selection of the resonant circuit network can increase the equivalent impedance in the EMI coupling path in the low frequency range, which further reduces the common mode interference. Finally, a simulation model and a 60W experimental prototype of the proposed converter are built and tested. Experimental results verify the theoretical analysis.

Nitrogen and Fluorine Dual-Doped Carbon Nanosheets for High-Performance Supercapacitors

Chen Jiao,Zhong Jie Zhang,Xiang Ying Chen 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.4

Doping carbon materials with heteroatoms such as N, F is an effective approach to elevating the capacitive performance of supercapacitors. In this paper, nitrogen and fluorine dual-doped two-dimensional (2D) porous carbon nanosheets (PCNSs) have been fabricated by a straightforward template carbonization method, using trisodium citrate as carbon source and self-template, and ammonium fluoride as N/F dopants. The N/F-doped carbon samples are well characterized by a series of techniques and measured in a three-electrode system and two-electrode system, respectively. As a result, N/F-doped carbon has delivered large capacitance of 110 F g -1 at 1 Ag -1 and high-energy density of 3.82 W h kg -1 at the power density of 0.5 kW kg -1. It is also revealed that semi-ionic C–F bonds in PCNSs have enhanced electrical conductivity, hence, facilitating electron transport in the electrode. For comparison, ammonium chloride is used as sole dopant for producing N-doped carbon materials, whose capacitive performances are much lower than the N/F-codoped one, indicating the synergistic effect of N/F for capacitive improvement.

Knockdown of HMGN5 Expression by RNA Interference Induces Cell Cycle Arrest in Human Lung Cancer Cells

Chen, Peng,Wang, Xiu-Li,Ma, Zhong-Sen,Xu, Zhong,Jia, Bo,Ren, Jin,Hu, Yu-Xin,Zhang, Qing-Hua,Ma, Tian-Gang,Yan, Bing-Di,Yan, Qing-Zhu,Li, Yan-Lei,Li, Zhen,Yu, Jin-Yan,Gao, Rong,Fan, Na,Li, Bo,Yang, Jun Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.7

HMGN5 is a typical member of the HMGN (high mobility group nucleosome-binding protein) family which may function as a nucleosomal binding and transcriptional activating protein. Overexpression of HMGN5 has been observed in several human tumors but its role in tumorigenesis has not been fully clarified. To investigate its significance for human lung cancer progression, we successfully constructed a shRNA expression lentiviral vector in which sense and antisense sequences targeting the human HMGN5 were linked with a 9-nucleotide loop. Inhibitory effects of siRNA on endogenous HMGN5 gene expression and protein synthesis were demonstrated via real-time RT-PCR and western blotting. We found HMGN5 silencing to significantly inhibit A549 and H1299 cell proliferation assessed by MTT, BrdU incorporation and colony formation assays. Furthermore, flow cytometry analysis showed that specific knockdown of HMGN5 slowed down the cell cycle at the G0/G1 phase and decreased the populations of A549 and H1299 cells at the S and G2/M phases. Taken together, these results suggest that HMGN5 is directly involved in regulation cell proliferation in A549 and H1299 cells by influencing signaling pathways involved in cell cycle progression. Thus, our finding suggests that targeting HMGN5 may be an effective strategy for human lung cancer treatment.

Retinoic Acid Promotes Interleukin-4 Plasmid-Dimethylsulfoxide Topical Transdermal Delivery for Treatment of Psoriasis

( Zhong Wen Chen ),( Yin Bing Zhang ),( Xaing Jun Chen ),( Xiao Liu ),( Zhen Wang ),( Xi Kun Zhou ),( Ji Qiu ),( Nan Nan Zhang ),( Xiu Teng ),( Yong Qiu Mao ),( Chang Yong Liu ),( Yu Quan Wei ),( Jion 대한피부과학회 2015 Annals of Dermatology Vol.27 No.3

Background: Psoriasis is an autoimmune disease that is caused by a shift in the Th1/Th2 balance toward Th1- dominant immunity. It has been established as an effective treatment to counteract psoriasis by subcutaneous injection of recombinant interleukin (IL)-4, and IL-4 gene therapy by topical transdermal penetration has shown its antipsoriatic effect in mice. Retinoic acid (RA) and dimethylsulfoxide can increase the efficiency of gene transfection in the topical transdermal delivery system. Objective: We investigated whether RA could improve anti-psoriasis efficiency using IL-4 expression plasmid pORF-mIL-4 (pIL-4) via transdermal delivery system in K14-vascular endothelial growth (K14- VEGF) factor transgenic mice. Methods: After pretreatment with RA, plasmid pIL-4 in 10% dimethylsulfoxide was applied to the ear skin by topical transdermal penetration. Hematoxylin- eosin staining and immunohistochemistry were performed with ear samples to evaluate anti-psoriasis efficiency in mice. Results: The psoriasis pathological features were relieved and psoriasis-associated factors were significantly reduced. Conclusion: Our results reveal that topical application of pIL-4 in dimethylsulfoxide by transdermal delivery with RA pretreatment can improve psoriasis significantly. (Ann Dermatol 27(2) 121∼127, 2015)

Retinoic Acid Promotes Interleukin-4 Plasmid-Dimethylsulfoxide Topical Transdermal Delivery for Treatment of Psoriasis

( Zhong Wen Chen ),( Yin Bing Zhang ),( Xaing Jun Chen ),( Xiao Liu ),( Zhen Wang ),( Xi Kun Zhou ),( Ji Qiu ),( Nan Nan Zhang ),( Xiu Teng ),( Yong Qiu Mao ),( Chang Yong Liu ),( Yu Quan Wei ),( Jion 대한피부과학회 2015 Annals of Dermatology Vol.27 No.2

Background: Psoriasis is an autoimmune disease that is caused by a shift in the Th1/Th2 balance toward Th1- dominant immunity. It has been established as an effective treatment to counteract psoriasis by subcutaneous injection of recombinant interleukin (IL)-4, and IL-4 gene therapy by topical transdermal penetration has shown its antipsoriatic effect in mice. Retinoic acid (RA) and dimethylsulfoxide can increase the efficiency of gene transfection in the topical transdermal delivery system. Objective: We investigated whether RA could improve anti-psoriasis efficiency using IL-4 expression plasmid pORF-mIL-4 (pIL-4) via transdermal delivery system in K14-vascular endothelial growth (K14- VEGF) factor transgenic mice. Methods: After pretreatment with RA, plasmid pIL-4 in 10% dimethylsulfoxide was applied to the ear skin by topical transdermal penetration. Hematoxylin- eosin staining and immunohistochemistry were performed with ear samples to evaluate anti-psoriasis efficiency in mice. Results: The psoriasis pathological features were relieved and psoriasis-associated factors were significantly reduced. Conclusion: Our results reveal that topical application of pIL-4 in dimethylsulfoxide by transdermal delivery with RA pretreatment can improve psoriasis significantly.(Ann Dermatol 27(2) 121∼127, 2015)

Protein target identification of ginsenosides in skeletal muscle tissues: discovery of natural small-molecule activators of muscle-type creatine kinase

Chen, Feiyan,Zhu, Kexuan,Chen, Lin,Ouyang, Liufeng,Chen, Cuihua,Gu, Ling,Jiang, Yucui,Wang, Zhongli,Lin, Zixuan,Zhang, Qiang,Shao, Xiao,Dai, Jianguo,Zhao, Yunan The Korean Society of Ginseng 2020 Journal of Ginseng Research Vol.44 No.3

Background: Ginseng effectively reduces fatigue in both animal models and clinical trials. However, the mechanism of action is not completely understood, and its molecular targets remain largely unknown. Methods: By screening for proteins that interact with the primary components of ginseng (ginsenosides) in an affinity chromatography assay, we have identified muscle-type creatine kinase (CK-MM) as a potential target in skeletal muscle tissues. Results: Biolayer interferometry analysis showed that ginsenoside metabolites, instead of parent ginsenosides, had direct interaction with recombinant human CK-MM. Subsequently, 20(S)-protopanaxadiol (PPD), which is a ginsenoside metabolite and displayed the strongest interaction with CK-MM in the study, was selected as a representative to confirm direct binding and its biological importance. Biolayer interferometry kinetics analysis and isothermal titration calorimetry assay demonstrated that PPD specifically bound to human CK-MM. Moreover, the mutation of key amino acids predicted by molecular docking decreased the affinity between PPD and CK-MM. The direct binding activated CK-MM activity in vitro and in vivo, which increased the levels of tissue phosphocreatine and strengthened the function of the creatine kinase/phosphocreatine system in skeletal muscle, thus buffering cellular ATP, delaying exercise-induced lactate accumulation, and improving exercise performance in mice. Conclusion: Our results suggest a cellular target and an initiating molecular event by which ginseng reduces fatigue. All these findings indicate PPD as a small molecular activator of CK-MM, which can help in further developing better CK-MM activators based on the dammarane-type triterpenoid structure.

Observation of the Trapping of Runaway Electrons into Local Magnetic Mirrors during Slide-away Discharges in the HT-7 Tokamak

Zhong Yong Chen,Bao Nian Wan,Yuejiang Shi 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.2

The trapping of runaway electrons into local magnetic mirrors in a toroidal magnetic field has been observed in slide away discharges in the HT-7 tokamak. When the discharges went into the slide-away region with Parail-Pogutse instabilities, strong oscillations in the hard X-ray flux and in the electron cyclotron emission are observed. The runaway electrons are trapped into the local magnetic mirrors when they are pitch angle scattered by the anomalous Doppler resonance effect.

Optical Properties of Zinc-oxide Films Determined Using Spectroscopic Ellipsometry with Various Dispersion Models

Zhong-Hong Dai,Jie Shao,Yi-Ming Chen,Yu-Xiang Zheng,Jia-Da Wu,Liang-Yao Chen,Rong-Jun Zhang 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.55 No.3

In this work, we have studied the optical properties of wurtizite zinc-oxide films grown on silicon (100) substrates by means of pulsed laser deposition (PLD). Spectroscopic ellipsometry and three dispersion models, namely, the Sellmeier, Cauchy, and Forouhi-Bloomer models, were applied for determining the optical constants of the ZnO thin films. A comparison was made between two samples that were deposited for 30 minutes (sample I) and 60 minutes (sample II), respectively. X-ray diffraction analysis indicates that there are two types of preferred-orientation, i.e., (101) and (100) orientations for sample I and II, respectively. Results show that the Cauchy model gives the best fit for the samples with least root mean square error (RMSE) whereas the Forouhi-Bloomer model is most suitable for the data analysis in both the transparent and the absorption regions. The optical properties extracted from different dispersion models have been compared with the data reported in the literature. The results given in this work show that different dispersion models should be applied to obtain the optical constants In this work, we have studied the optical properties of wurtizite zinc-oxide films grown on silicon (100) substrates by means of pulsed laser deposition (PLD). Spectroscopic ellipsometry and three dispersion models, namely, the Sellmeier, Cauchy, and Forouhi-Bloomer models, were applied for determining the optical constants of the ZnO thin films. A comparison was made between two samples that were deposited for 30 minutes (sample I) and 60 minutes (sample II), respectively. X-ray diffraction analysis indicates that there are two types of preferred-orientation, i.e., (101) and (100) orientations for sample I and II, respectively. Results show that the Cauchy model gives the best fit for the samples with least root mean square error (RMSE) whereas the Forouhi-Bloomer model is most suitable for the data analysis in both the transparent and the absorption regions. The optical properties extracted from different dispersion models have been compared with the data reported in the literature. The results given in this work show that different dispersion models should be applied to obtain the optical constants