The Study of International Cooperation on Emergencies

An Chen,Jing Rui Chen,Fei Chi 위기관리 이론과 실천 2017 Journal of Safety and Crisis Management Vol.7 No.1

International cooperation on emergencies is significant to the response of these emergencies. Firstly, the connotation and characteristics of international cooperation on emergencies were analyzed. Secondly, the typical types of emergencies in need of international cooperation, the types of countries involved in international cooperation and the typical types of international cooperation modes on emergencies were analyzed in order to explain the mechanism of international cooperation. Finally, some strategies of international cooperation on emergencies were proposed. The result shows that, in order to have a better international cooperation, international cooperation modes on emergencies should be determined according to the types of emergencies, the situations of countries and organizations involved in it.

Dislocation Density-Based Constitutive Model and Processing Map for T2 Copper During Isothermal and Time-Variant Deformation

Gang Chen,Yu Jin,Jing Wang,Cheng Zhang,Qiang Chen,Hongming Zhang,Xingjian Zhao,Zhiyong Li,Changhai Xie,Zhiming Du 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.9

Isothermal compression tests were carried out to study the hot deformation behavior of T2 copper under various conditions. The deformation parameters, such as temperature and strain rate, have strong influence on flow stress and microstructureevolution of the alloy. A unified dislocation density-based model considering dynamic recovery and recrystallization wasestablished. And material parameters of the developed model were optimized by genetic algorithm. Comparisons betweenthe experimental and model data demonstrates that the developed model can precisely describe the flow behavior at quitewide range of deformation conditions. Meanwhile, the designed iterative procedure allows the model to be applied in timevariantdeformation conditions. Processing map and microstructure examination were constructed to optimize the processingwindow of the studied alloy. According to the processing maps, flow instability mainly appeared at low temperatures of500–650 °C and strain rates higher than 0.1 s−1. The optimum deformation parameters of T2 copper was concluded as thetemperature range of 700–800 °C and the strain rate of 0.1–1 s−1.

Experimental Evidence for Drude-Boltzmann-Like Transport in a Two-Dimensional Electron Gas in an AlGaN/GaN Heterostructure

Jing-Han Chen,C.-T. Liang,D.H. Youn,Eun-Jin Lee,Gil-Ho Kim,Hun Park,Hyun-Ick Cho,Jung-Hee Lee,Jung-Kai Tsai,Jyun-Ying Lin,Y. F. Chen 한국물리학회 2006 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.48 No.6

AlGaN/GaN heterostructures have been attracting a great deal of interest because of their great potential applications as light-emitting-diodes, high-electron-mobility transistors (HEMTs), and detectors operating in the visible-to-ultraviolet range. The performances of these devices are governed by the electronic properties of the two-dimensional electron gas (2DEG) formed at the interface of AlGaN/GaN heterostructure. In this work, we report transport measurements for an AlGaN/GaN 2DEG as functions of the magnetic field B over a wide range of temperature (4.682 K T 80 K). At the highest measurement temperature of 80 K, the longitudinal resistance is nominally Bindependent, compelling experimental evidence for Drude-Boltzmann-like transport in a 2D system.

Uncovering the Face of Android Ransomware: Characterization and Real-Time Detection

Chen, Jing,Wang, Chiheng,Zhao, Ziming,Chen, Kai,Du, Ruiying,Ahn, Gail-Joon IEEE 2018 IEEE transactions on information forensics and sec Vol.13 No.5

<P>In recent years, we witnessed a drastic increase of ransomware, especially on popular mobile platforms including Android. Ransomware extorts victims for a sum of money by taking control of their devices or files. In light of their rapid growth, there is a pressing need to develop effective countermeasure solutions. However, the research community is still constrained by the lack of a comprehensive data set, and there exists no insightful understanding of mobile ransomware in the wild. In this paper, we focus on the Android platform and aim to characterize existing Android ransomware. Specifically, we have managed to collect 2,721 ransomware samples that cover the majority of existing Android ransomware families. Based on these samples, we systematically characterize them from several aspects, including timeline and malicious features. In addition, the detection results of existing anti-virus tools are rather disappointing, which clearly calls for customized anti-mobile-ransomware solutions. To detect ransomware that extorts users by encrypting data, we propose a novel real-time detection system, called RansomProber. By analyzing the user interface widgets of related activities and the coordinates of users’ finger movements, RansomProber can infer whether the file encryption operations are initiated by users. The experimental results show that RansomProber can effectively detect encrypting ransomware with high accuracy and acceptable runtime performance.</P>

Current state of research about acupuncture for the treatment of COVID-19: A scoping review

Chen Chen,Jie Zhan,Hao Wen,Xiaojing Wei,Lu Ding,Chenyang Tao,Cui Li,Peiming Zhang,Yuyuan Tang,Jing-chun Zeng,Li-ming Lu 한국한의학연구원 2021 Integrative Medicine Research Vol.10 No.-

Background Since the outbreak of coronavirus disease (COVID-19), acupuncture has been widely used in the treatment of COVID-19. The research community has responded rapidly and has already published many research articles about this topic. Methods We searched PubMed, Embase, Cochrane Library as well as CNKI, Wanfang and VIP from January 1, 2020 to July 31, 2021. The dates of publication, language of publication, methodological characteristics and the key findings were analyzed separately. The data are presented as bar graphs, structured tables and figures. Results In this scoping review, 16 research articles were included: 7 case reports, 6 observational studies, 1 review, 1 RCT and 1 nonrandomized clinical trial. The majority of the articles (81.3%) were published by Chinese scholars, 12.5% articles were by scholars in the United States, and 6.3% articles were by scholars in Iran. The included studies reported that acupuncture could alleviate the symptoms of COVID-19 patients, shorten their hospitalization days, and is effective for the elderly. There were no side effects reported. The most frequent acupoints used were LI4, PC6, ST36 and KI3. They reported many obstacles in implementing acupuncture therapy for treating COVID-19 patients. Conclusion Acupuncture has a good effect for the treatment of COVID-19, but high-quality evidence support is still lacking. Coupled with the difficulties that acupuncturists experienced during the process of treatment, the promotion of acupuncture treatment for COVID-19 faces many obstacles. Background Since the outbreak of coronavirus disease (COVID-19), acupuncture has been widely used in the treatment of COVID-19. The research community has responded rapidly and has already published many research articles about this topic. Methods We searched PubMed, Embase, Cochrane Library as well as CNKI, Wanfang and VIP from January 1, 2020 to July 31, 2021. The dates of publication, language of publication, methodological characteristics and the key findings were analyzed separately. The data are presented as bar graphs, structured tables and figures. Results In this scoping review, 16 research articles were included: 7 case reports, 6 observational studies, 1 review, 1 RCT and 1 nonrandomized clinical trial. The majority of the articles (81.3%) were published by Chinese scholars, 12.5% articles were by scholars in the United States, and 6.3% articles were by scholars in Iran. The included studies reported that acupuncture could alleviate the symptoms of COVID-19 patients, shorten their hospitalization days, and is effective for the elderly. There were no side effects reported. The most frequent acupoints used were LI4, PC6, ST36 and KI3. They reported many obstacles in implementing acupuncture therapy for treating COVID-19 patients. Conclusion Acupuncture has a good effect for the treatment of COVID-19, but high-quality evidence support is still lacking. Coupled with the difficulties that acupuncturists experienced during the process of treatment, the promotion of acupuncture treatment for COVID-19 faces many obstacles.

Protective Effect Against Hydroxyl Radical-induced DNA Damage and Antioxidant Mechanism of [6]-gingerol: A Chemical Study

Jing Lin,Xican Li,Li Chen,Weizhao Lu,Xianwen Chen,Lu Han,Dongfeng Chen 대한화학회 2014 Bulletin of the Korean Chemical Society Vol.35 No.6

[6]-Gingerol is known as the major bioactive constituent of ginger. In the study, it was observed to effectively protect against •OH-induced DNA damage (IC50 328.60 ± 24.41 μM). Antioxidant assays indicated that [6]- gingerol could efficiently scavenge various free radicals, including •OH radical (IC50 70.39 ± 1.23 μM), •O2 − radical (IC50 228.40 ± 9.20 μM), DPPH• radical (IC50 27.35 ± 1.44 μM), and ABTS+• radical (IC50 2.53 ± 0.070 μM), and reduce Cu2+ ion (IC50 11.97 ± 0.68 μM). In order to investigate the possible mechanism, the reaction product of [6]-gingerol and DPPH• radical was further measured using HPLC combined mass spectrometry. The product showed a molecular ion peak at m/z 316 [M+Na]+, and diagnostic fragment loss (m/z 28) for quinone. On this basis, it can be concluded that: (i) [6]-gingerol can effectively protect against •OH-induced DNA damage; (ii) a possible mechanism for [6]-gingerol to protect against oxidative damage is •OH radical scavenging; (iii) [6]-gingerol scavenges •OH radical through hydrogen atom (H•) transfer (HAT) and sequential electron (e) proton transfer (SEPT) mechanisms; and (iv) both mechanisms make [6]-gingerol be oxidized to semi-quinone or quinone forms.

Efficient degradation of imidacloprid in wastewater by a novel p-n heterogeneous Ag2O/BiVO4/diatomite composite under hydrogen peroxide

Jing Chen,Qifang Ren,Chunshan Xu,Bin Chen,Shaohua Chen,Yi Ding,Zhen Jin,Wanmi Guo,Xinyu Jia 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.123 No.-

In this study, Ag2O/BiVO4/diatomite composite with p-n heterojunction structure was synthesized bysimple hydrothermal method with diatomite as carrier. It was found that under the action of hydrogenperoxide (H2O2), the imidacloprid (IMD) could be effectively degraded by the composite. Systemic evaluationswas conducted on effects of pH value, catalyst dosage, H2O2 concentration, initial IMD concentration,and anion on how effeciently this new photocatalytic composite can degrade IMD. The results showthat the p-n heterojunction formed between the two contact surfaces of Ag2O nanoparticle and BiVO4promotes the charge transfer between the interfaces, inhibits recombination of electrons and holes,and thus significantly improves the catalytic performance. The stability and reusability of Ag2O/BiVO4/diatomite composites were tested with ICP experiment and cyclic experiment. Active substancecapture experiment and ESR reveal the photocatalytic reaction mechanism and confirm that superoxideradical (O2), hydroxyl radical (OH), and h+ can promote the degradation of IMD. The degradation productsand the intermediates of IMD were identified through LC-MS, on a basis of which the possible transformationpathway was proposed. In situ synthesis of p-type Ag2O and n-type BiVO4 heterojunctioncomposites has opened a new direction for photocatalytic degradation of organic pollutants.

Protective Effect Against Hydroxyl Radical-induced DNA Damage and Antioxidant Mechanism of [6]-gingerol: A Chemical Study

Lin, Jing,Li, Xican,Chen, Li,Lu, Weizhao,Chen, Xianwen,Han, Lu,Chen, Dongfeng Korean Chemical Society 2014 Bulletin of the Korean Chemical Society Vol.35 No.6

[6]-Gingerol is known as the major bioactive constituent of ginger. In the study, it was observed to effectively protect against ${\bullet}OH$-induced DNA damage ($IC_{50}$ $328.60{\pm}24.41{\mu}M$). Antioxidant assays indicated that [6]-gingerol could efficiently scavenge various free radicals, including ${\bullet}OH$ radical ($IC_{50}$ $70.39{\pm}1.23{\mu}M$), ${\bullet}O_2{^-}$ radical ($IC_{50}$ $228.40{\pm}9.20{\mu}M$), $DPPH{\bullet}$radical ($IC_{50}$ $27.35{\pm}1.44{\mu}M$), and $ABTS{^+}{\bullet}$radical ($IC_{50}$ $2.53{\pm}0.070{\mu}M$), and reduce $Cu^{2+}$ ion ($IC_{50}$ $11.97{\pm}0.68{\mu}M$). In order to investigate the possible mechanism, the reaction product of [6]-gingerol and $DPPH{\bullet}$ radical was further measured using HPLC combined mass spectrometry. The product showed a molecular ion peak at m/z 316 $[M+Na]^+$, and diagnostic fragment loss (m/z 28) for quinone. On this basis, it can be concluded that: (i) [6]-gingerol can effectively protect against ${\bullet}OH$-induced DNA damage; (ii) a possible mechanism for [6]-gingerol to protect against oxidative damage is ${\bullet}OH$ radical scavenging; (iii) [6]-gingerol scavenges ${\bullet}OH$ radical through hydrogen atom ($H{\bullet}$) transfer (HAT) and sequential electron (e) proton transfer (SEPT) mechanisms; and (iv) both mechanisms make [6]-gingerol be oxidized to semi-quinone or quinone forms.

정사각형 단면을 갖는 180° 곡관에서 위치별 속도분포특성 및 직관거리의 유효성에 관한 연구

진정정(Jing-Jing Chen),윤준규(Jun-Kyu Yoon) 한국산학기술학회 2016 한국산학기술학회논문지 Vol.17 No.10

본 연구는 정사각형 단면 180° 곡관 내의 유동특성을 파악하기 위해 RSM 난류모델을 이용하여 작동유체, 입구의 공기속도, 관내의 표면조도, 곡률반경 및 수력직경 등의 다양한 유동인자를 변경하여 각도 위치별 속도분포특성을 수치해석을 통하여 고찰하였다. CFD 해석시 경계조건은 공기와 물의 입구온도를 288 K, 293 K로 설정하였고, 입구의 공기속도, 관내의 표면조도, 곡률반경 및 수력직경은 각각 3∼15 m/s, 0∼0.001 mm, 2.5∼4.5D, 70∼100 mm로 적용하여 해석을 수행하였다. 그 결과를 정리하면, 작동유체의 유동특성은 유체의 점성력 차이로 속도분포가 크게 달라짐을 알 수 있었고, 곡관부 내에서의 최대 속도프로파일은 90° 단면위치에서 X/D=0.8 영역으로 나타났으며, 180° 단면위치에서는 Y/D=0.8 영역으로 나타났다. 그리고 관내의 표면조도가 낮고, 곡률반경이 클수록 속도변화율은 크게 변하여 나타냈다. 또한 곡관후류의 직관부에서 유동편차가 안정화되는 직관거리는 L/D=30 영역에서 나타내어 유량 계측시 유효한 측정위치로 잘 제시할 수 있었으며, 수력직경에 따라 곡관후류 직관부의 표준편차특성은 동일한 유속일 때 최소의 편차영역은 대체로 직관거리 L/D=15∼30 범위로 나타났다. This study numerically analyzes the characteristics of the velocity distribution for each location of a square-sectional 180° bent duct using a Reynolds Stress Turbulent model. The flow parameters were varied, including the working fluids, inlet velocity, surface roughness, radius of curvature, and hydraulic diameter. The boundary conditions for computational fluid dynamics analysis were inlet temperatures of air and water of 288 K and 293 K, inlet air velocity of 3-15 m/s, inner surface roughness of 0-0.001 mm, radius of curvature of 2.5-4.5 D, and hydraulic diameter of 70-100 mm. The working fluid characteristics were highly affected by changes in the viscous force. The maximum velocity profiles in the bent duct were indicated when the 90° section was in the region of X/D=0.8 and the 180° section was in the region of Y/D=0.8. Lower surface roughness and higher radius of curvature resulted in a higher rate of velocity change. Also, an efficient measuring location downstream of the bent duct is suggested since the flow deviations were the most stable when the straight duct length was in the region of L/D=30. The minimum deviations at the same velocity conditions according to the hydraulic diameter were mostly indicated in the range of L/D=15-30 based on the standard deviation characteristics.

Asiatic Acid Protects Dopaminergic Neurons from Neuroinflammation by Suppressing Mitochondrial ROS Production

( Dong Chen ),( Xiao-ya Zhang ),( Jing Sun ),( Qi-jie Cong ),( Wei-xiong Chen ),( Hafiz Muhammad Ahsan ),( Jing Gao ),( Jin-jun Qian ) 한국응용약물학회 2019 Biomolecules & Therapeutics(구 응용약물학회지) Vol.27 No.5

This study sought to evaluate the effects of Asiatic acid in LPS-induced BV2 microglia cells and 1-methyl-4-phenyl-pyridine (MPP+)-induced SH-SY5Y cells, to investigate the potential anti-inflammatory mechanisms of Asiatic acid in Parkinson’s disease (PD). SH-SY5Y cells were induced using MPP+ to establish as an in vitro model of PD, so that the effects of Asiatic acid on dopaminergic neurons could be examined. The NLRP3 inflammasome was activated in BV2 microglia cells to explore potential mechanisms for the neuroprotective effects of Asiatic acid. We showed that Asiatic acid reduced intracellular production of mitochondrial reactive oxygen species and altered the mitochondrial membrane potential to regulate mitochondrial dysfunction, and suppressed the NLRP3 inflammasome in microglia cells. We additionally found that treatment with Asiatic acid directly improved SH-SY5Y cell viability and mitochondrial dysfunction induced by MPP+. These data demonstrate that Asiatic acid both inhibits the activation of the NLRP3 inflammasome by downregulating mitochondrial reactive oxygen species directly to protect dopaminergic neurons from, and improves mitochondrial dysfunction in SH-SY5Y cells, which were established as a model of Parkinson’s disease. Our finding reveals that Asiatic acid protects dopaminergic neurons from neuroinflammation by suppressing NLRP3 inflammasome activation in microglia cells as well as protecting dopaminergic neurons directly. This suggests a promising clinical use of Asiatic acid for PD therapy.