De Facto Exchange Rate Regimes in East Asia

Jingjing Meng 한국경제연구학회 2015 Korea and the World Economy Vol.16 No.1

East Asian economies have taken a variety of exchange rate reforms since the 1997-1998 financial crisis. This paper seeks to explore the evolution of exchange rate regimes in the region based on data from 2003 to 2014. By using a seemingly unrelated regression model, this paper presents evidence of increased links among East Asian economies. The results are three-fold: (i) exchange rate regimes in a number of East Asian economies have changed considerably over time; (ii) the role of the US dollar became more important during the recent global financial crisis; (iii) average correlation among exchange rates of East Asian currencies increased over time after controlling for the effect of potentially important international and regional currencies including the US dollar, the euro and the Japanese yen. The result implies important unobserved common factor that influences daily exchange rate movements of East Asian economies, providing evidence of increased economic linkages among East Asian economies.

Total Synthesis of Hoiamide A Using an Evans-Tishchenko Reaction as a Key Step

Guo, Yian,Zhou, Jingjing,Gao, Bowen,Zhao, Meng,Yan, Jia-Lei,Xu, Zhengshuang,Choi, Sun,Ye, Tao THE AMERICAN CHEMICAL SOCIETY 2019 ORGANIC LETTERS Vol.21 No.14

<P>The first total synthesis of neurotoxic cyclodepsipeptide hoiamide A (<B>1</B>) has been accomplished. The synthesis features the use of an Evans-Tishchenko fragment coupling between a five-stereogenic-center-containing β-hydroxyketone and a chiral aldehyde derived from threonine.</P> [FIG OMISSION]</BR>

Enhancing the Ag Precipitation by Surface Mechanical Attrition Treatment on Cu-Ag Alloys

Jiabin Liu,Lehao Zhang,Jingjing Liu,Liuyi Huang,Hao Gu,Youtong Fang,Liang Meng,Jian Zhang 대한금속·재료학회 2016 METALS AND MATERIALS International Vol.22 No.5

The influence of surface mechanical attrition treatment (SMAT) on Ag precipitation in Cu-Ag alloys was investigated. Cu-6 wt% Ag was melt, cold rolled and solution treated to be Cu-Ag solid solution, which was either aged at 250 and 350 °C for 24 h directly or SMAT-ed before aging. Ag precipitates were hard be found in the directly aged Cu-Ag sample while they were observed clearly in the SMAT-ed counterpart at 250 °C. The Ag precipitates formed in the surface layer by SMAT are much coarser than those in the un-SMAT-ed sample. It is obvious that the precipitating behavior of Ag was promoted significantly by SMAT approach. A large number of defects were generated by SMAT and they were acting as fast atomic diffusion channels that facilitated the atomic diffusion of Ag.

Juvenoids on aphids to prolong optimal stages

Lai Rongquan,Bai Jingjing,Gu Gang,Zhou Ting,Mi Yuee,Zhang Bang,Han Meng,Bai Jianbao 한국곤충학회 2021 Entomological Research Vol.51 No.3

In recent years, Aphidius gifuensis, a critical parasitoid, has been increasingly used to control Myzus persicae in tobacco. However, problems due to inconsistent emergence and insufficient numbers of A. gifuensis to control M. persicae have arisen in artificial reproduction. Here, we investigated the effects of the juvenoids ZR-512, ZR-777, ZR-515, fenoxycarb and juvenile hormone (JH) III on the performance of M. persicae, the activities of molting enzymes and parasitism rates. The aim was to identify juvenoids that may prolong the ‘arrived too early’ optimal stages of M. persicae for A. gifuensis parasitism to address the problems mentioned above. The results showed that the developmental durations of 2nd- and 3rd-instar nymphs of the parental (F0) and offspring (F1) generations of M. persicae were significantly prolonged by juvenoid treatment. The instar durations ranged from 4.00 to 13.67 h for the parental generation and from 8.00 to 32.00 h for the offspring. M. persicae lifespan was not significantly affected by the juvenoids, whereas fecundity was. Additionally, the phenoloxidase and chitinase contents and activities in M. persicae were significantly reduced by the juvenoids, whereas the parasitism rate of A. gifuensis on M. persicae was unaffected. Our study provides information that can help prolong the ‘arrived too early’ period of effective parasitism of M. persicae nymphs by A. gifuensis and thereby benefit the large-scale artificial reproduction of A. gifuensis. These findings will enhance the biological control of M. persicae and highlight the mechanism by which juvenoids affect M. persicae development by regulating phenoloxidase or chitinase.

Discovery, semisynthesis, biological activities, and metabolism of ocotillol-type saponins

Juan Liu,Yangrong Xu,Jingjing Yang,Wenzhi Wang,Jianqiang Zhang,Renmei Zhang,Qingguo Meng 고려인삼학회 2017 Journal of Ginseng Research Vol.41 No.3

Ocotillol-type saponins are one kind of tetracyclic triterpenoids, sharing a tetrahydrofuran ring. Natural ocotillol-type saponins have been discovered in Panax quinquefolius L., Panax japonicus, Hana mina, and Vietnamese ginseng. In recent years, the semisynthesis of 20(S/R)-ocotillol-type saponins has been reported. The biological activities of ocotillol-type saponins include neuroprotective effect, antimyocardial ischemia, antiinflammatory, antibacterial, and antitumor activities. Owing to their chemical structure, pharmacological actions, and the stereoselective activity on antimyocardial ischemia, ocotillol-type saponins are subjected to extensive consideration. In this review, we sum up the discovery, semisynthesis, biological activities, and metabolism of ocotillol-type saponins.

Discovery, semisynthesis, biological activities, and metabolism of ocotillol-type saponins

Liu, Juan,Xu, Yangrong,Yang, Jingjing,Wang, Wenzhi,Zhang, Jianqiang,Zhang, Renmei,Meng, Qingguo The Korean Society of Ginseng 2017 Journal of Ginseng Research Vol.41 No.3

Ocotillol-type saponins are one kind of tetracyclic triterpenoids, sharing a tetrahydrofuran ring. Natural ocotillol-type saponins have been discovered in Panax quinquefolius L., Panax japonicus, Hana mina, and Vietnamese ginseng. In recent years, the semisynthesis of 20(S/R)-ocotillol-type saponins has been reported. The biological activities of ocotillol-type saponins include neuroprotective effect, antimyocardial ischemia, antiinflammatory, antibacterial, and antitumor activities. Owing to their chemical structure, pharmacological actions, and the stereoselective activity on antimyocardial ischemia, ocotillol-type saponins are subjected to extensive consideration. In this review, we sum up the discovery, semisynthesis, biological activities, and metabolism of ocotillol-type saponins.

Three-Dimensional Upper Bound Limit Analysis of Tunnel Stability with an Extended Collapse Mechanism

Zhizhen Liu,Ping Cao,Fei Wang,Jingjing Meng,Rihong Cao,Jingshuo Liu 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.12

A three-dimensional collapse mechanism that can consider a combined collapse of the tunnel roof and the side walls is proposed in this work. The three-dimensional upper bound support pressure is formulated with the power balance principal in the upper bound theorem. The nonlinear Mohr-Coulomb failure criterion is used to replace the commonly used linear Mohr-Coulomb failure criterion. The method has been validated by a series of examples, in which the three-dimensional collapse mechanism and support pressures are in a good agreementwith the numerical results and solutions found in the literatures. Furthermore, sensitivity analyses of the geotechnical and geometrical parameters on the support pressure areconducted and the collapsing range is measured. The results show that a higher value of nonlinear failure coefficient, tensile strength, initial cohesion and tangential internal friction angle can increase tunnel stability, while tunnel stability is threatened by a higher value of burial depth, unit weight, tunnel width and height. The predicted collapse range increases noticeably with the increase of the nonlinear coefficient. This study is of great significance for predicting the three-dimensional safety support pressure and collapse mechanism of tunnel.

Mechanical Stimulation and Diameter of Fiber Scaffolds Affect the Differentiation of Rabbit Annulus Fibrous Stem Cells

Zhou Pinghui,Wei Bangguo,Guan Jingjing,Chen Yu,Zhu Yansong,Ye Yuchen,Meng Yue,Guan Jianzhong,Mao Yingji 한국조직공학과 재생의학회 2021 조직공학과 재생의학 Vol.18 No.1

BACKGROUND: Degeneration of the annulus fibrosus (AF), an important structure of the intervertebral disc, is one of the main causes of degenerative disc disease. Fabrication of scaffolds replicating the stratified microstructure of the AF is critical for the successful regeneration of AF. METHODS: In this study, we cultured rabbit AF-derived stem cells (AFSCs) using fabricated electrospun fibrous poly-L-lactic acid scaffolds with different diameters. We applied cyclic tensile strain (CTS) on the scaffolds to regulate the differentiation of AFSCs into specific cell types that resided at the inner, middle, and outer zones of the AF. RESULTS: We found that the morphologies of AFSCs on the smaller-fiber-diameter scaffolds were nearly round, whereas spindle-like cells morphologies were observed on large-diameter scaffolds. CTS enhanced these phenomena and made the cells slender. The expression levels of collagen-I in cells increased as a function of the fiber diameter, whereas collagen-II and aggrecan exhibited opposite trends. Moreover, the application of CTS upregulated the gene expressions of collagen-I, collagen-II, and aggrecan. CONCLUSION: Overlaying the scaffolds with different CTS-stimulated cells could eventually lead to engineered AF tissues with hierarchical structures that approximated the native AF tissue. Thus, the proposed methodologies could be potentially applied for AF regeneration. BACKGROUND: Degeneration of the annulus fibrosus (AF), an important structure of the intervertebral disc, is one of the main causes of degenerative disc disease. Fabrication of scaffolds replicating the stratified microstructure of the AF is critical for the successful regeneration of AF. METHODS: In this study, we cultured rabbit AF-derived stem cells (AFSCs) using fabricated electrospun fibrous poly-L-lactic acid scaffolds with different diameters. We applied cyclic tensile strain (CTS) on the scaffolds to regulate the differentiation of AFSCs into specific cell types that resided at the inner, middle, and outer zones of the AF. RESULTS: We found that the morphologies of AFSCs on the smaller-fiber-diameter scaffolds were nearly round, whereas spindle-like cells morphologies were observed on large-diameter scaffolds. CTS enhanced these phenomena and made the cells slender. The expression levels of collagen-I in cells increased as a function of the fiber diameter, whereas collagen-II and aggrecan exhibited opposite trends. Moreover, the application of CTS upregulated the gene expressions of collagen-I, collagen-II, and aggrecan. CONCLUSION: Overlaying the scaffolds with different CTS-stimulated cells could eventually lead to engineered AF tissues with hierarchical structures that approximated the native AF tissue. Thus, the proposed methodologies could be potentially applied for AF regeneration.

A Novel e8a2BCR-ABL1 Fusion Transcript without Insertion Sequence in a Patient with Chronic Myeloid Leukemia

Caibao Jin,Xiaojian Zhu,Min Xiao,Songya Liu,Xian Liu,Jingjing Liu,Xiuwen Xu,Shujuan Yi,Li Meng 대한진단검사의학회 2018 Annals of Laboratory Medicine Vol.38 No.2

Chronic myeloid leukemia (CML) is a clonal hematopoietic stem cell disorder characterized by a reciprocal translocation between the long arms of chromosomes 9 and 22, resulting in the formation of a Philadelphia (Ph) chromosome. Most chimeric BCR-ABL1 fusion transcripts are e13a2(b2a2) or e14a2(b3a2), encoding a 210-kDa protein, p210, but some are a e1a2 transcript or e19a2 transcript encoding a 190-kDa protein or a 230-kDa protein, respectively [1]

Optimization of Self-Powered Time Temperature Indicator for the Operation and Performance

Do Yeob Kim,Dong Youl Kim,Ji Hye Kim,Meng Jingjing,Sang Bong Lee,Jung Hwa Yang,Seung Won Jung,Seung Ju Lee 한국산업식품공학회 2016 학술대회 및 심포지엄 Vol.2016 No.10

A self-powered time-temperature indicator (TTI) was optimized to enhance the performance of the TTI by modifying a biofuel cell using different immobilization, redox mediators, and status of electrode. The performance of the TTI was measured by output voltage of the TTI. The enzymes and combinations of lacasse mediators (HBT (1-hydroxybenzotriazole), Rupy (Bis-(bipyridine)-(5-aminophenanthroline) ruthenium bis (hexafluorophosphate)), MB (Methylene blue), SDP (4,4- sulfonyldiphenol)) and glucose oxidase mediators (FA (Ferroceneboxaldehyde), DBQ(2,5-dihydroxybenzoquinone), HQS (8-hydroxyquinoline-5sulfonic acid hydrate), FHFP (Ferrocenium hexafluorophosphate)) were immobilized with stabilizers (pyrrole) on a glassy carbon electrode by electrodeposition by applying a square wave, cross-linking and physical immobilization. MWCNTs were used to modify glassy carbon electrodes. MWCNTs coated electrodes produced higher output voltage than uncoated electrodes. The optimum and stable performance of the self-powered TTI was that the output voltage of 64 mV and duration time was 3hr at 25°C, when the combination of Rupy, MB for laccase mediators and HQS, FHFP for glucose oxidase mediators were immobilized on MWCNTs coated electrodes by applying a square wave method. In the application, the concentrations of enzyme and glucose were adjusted to prolong the shelf-life of TTI at much lower output voltage.