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Tetramic acid-motif natural products from a marine fungus Tolypocladium cylindrosporum FB06 and their anti-Parkinson activities

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Marine Life Science & Technology 2024年第1期6卷 84-92页

作者： yuna Jung Chaesun kwon Taeyeon Kim Jin Woo Lee Min-Kyoo Shin Sang Hee Shim Natural Products Research Institute College of PharmacySeoul National UniversitySeoul 08826Republic of Korea College of Pharmacy and Research Institute of Pharmaceutical Sciences Seoul National UniversitySeoul 08826Republic of Korea College of Pharmacy Duksung Women’s UniversitySeoul 01369Republic of Korea

Tetramic acid-containing natural products are attracting significantly increasing attention from biologists and chemists due to their intriguing structures and biological *** the present study,two new tetramic acid alkaloids tolypyridone I(1)and tolypyridone J(2),together with five known ones(3–7),were isolated from cultures of a marine fungus Tolypocladium cylindrosporum FB06 isolate obtained from a marine sediment in Beaufort sea of North *** structures were elucidated using 1D,2D NMR,and *** configurations were established on the basis of 1H coupling constants,RoESy correlations and DP4 *** 2 was isolated as mixtures of rotational isomers with C-3 to C-7 axis between 4-hydroxy-2-pyridone and 1-ethyl-3,5-dimethylcyclohexane,hindering *** our unbiased screening to discover neuroprotective compounds in an in vitro Parkinson’s disease(PD)model,SH-Sy5y dopaminergic cells were treated with isolated compounds followed by treatment with 1-methyl-4-phenylpyridinium(MPP^(+)),a parkinsonian *** tested compounds,F-14329(7)significantly protected cells from MPP^(+)-induced ***^(+)-mediated cell death is known to be related to the regulation of Bcl-2 family proteins,specifically the down-regulation of anti-apoptotic Bcl-2 and the up-regulation of pro-apoptotic Bax *** with 2 mmol/L of MPP^(+)for 24 h significantly reduced Bcl-2 levels compared to control treated with ***,treatment with F-14329(7)attenuated such *** study demonstrates that tetramic acid-motif compounds could be potential lead compounds for treating PD.

关键词： Tolypocladium cylindrosporum Tetramic acid Tolypyridone Parkinson’s disease

The Effect of Non-equilibrium Condensation on the Drag Coefficient in a Transonic Airfoil Flow

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Journal of Thermal Science 2012年第6期21卷 518-524页

作者： I.W.Kim M.M.A.Alam S.J.Lee y.D.kwon S.B.kwon School of Mechanical Engineering Kyungpook Nat.Uni.1370Sankyuk-dongDaegu 702-701Korea Dept.of Advanced & Control Eng.Saga Uni.Japan

In this study, a transonic flow past NACA0012 profile at angle of attack α=0^0 whose aspect ratio AR is 1.0 with non-equilibrium condensation is analyzed by numerical analysis using a TVD scheme and is investigated using an intermittent indraft type supersonic wind tunnel. Transonic flows of 0.78-0.90 in free stream Mach number with the variations of the stagnation relative humidity（φ0） are tested. For the same free stream Mach number, the increase in φ0 causes decrease in the drag coefficient of profile which is composed of the drag components of form, viscous and wave. In the case of the same Moo and To, for more than φ0=30%, despite the irreversibility of process in non-equilibrium condensation, the drag by shock wave decreases considerably with the increase of φ0. on the other hand, it shows that the effect of condensation on the drag coefficients of form and viscous is negligible. As an example, the decreasing rate in the drag coefficient of profile caused by the influence of non-equilibrium condensation for the case of M∞=0.9 and φ0 =50% amounts to 34%. Also, it were turned out that the size of supersonic bubble （that is, the maximum height of supersonic zone） and the deviation of pressure coefficient from the value for M=1 decrease with the increase of φ0 for the same M∞.

关键词： Non-equilibrium condensation Transonic Moist air Drag coefficient Pressure coefficient

MoDELING　oF　SUPERPLASTIC　FoRMING　PRoCESS　FoR　ALUMINUM　ALLoyS　WITH　STRAIN　HARDENING　EFFECT

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Acta Metallurgica Sinica(English Letters) 1996年第6期9卷 537-544页

作者： y.N. kwon and y.-W. Chang(Center for Advanced Aerospace Materials (CAAM), Pohang University of Science and Technology, Pohang 790-784. Korea ) Pohang Univ of Science and Technology Pohang South Korea

Superplastic forming of a thin sheet into complex shape is an important manufacturing process especially in aerospace industry. The main objective of modeling the superplastic forming process is to predict the forming pressure-time cycle to maintain the optimum strain rate and the resulting thickness distribution. There have been many attempts to model superplastic forming process using the various techniques including finite element method. However, most of these attempts so far have disregarded the strain hardening effect which occurs in several superplastic materials. In this study,we have used ABAQUS finite element code to predict the suitable processing variables during an axisymmetric cup forming of Supral 100 and 7075Al alloys to examine the strain hardening effects on forming. The performance of numerical results was then compared with the experimental results.

关键词： superplastic forming strain hardening supral 100 7075Al FEM

PRoDUCTIoN AND DECAy oF b-FLAVoRED HADRoNS

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Chinese Physics C 2016年第10期40卷 746-758页

作者： P. Eerola M. Kreps y. kwon U. of Helsinki Helsinki Finland U. of Warwick Coventry UK yonsei U. Seoul Korea

The b quark belongs to the third generation of quarks and is the weak-doublet partner of the t quark. The existence of the third-generation quark doublet was proposed in 1973 by Kobayashi and Maskawa [1] in their model of the quark mixing matrix （＂CKM＂ matrix）, and confirmed four years later by the first observation of a bb meson [2]. In the KM model, CP violation is explained within the Standard Model （SM） by an irreducible phase of the 3 × 3 unitary matrix. The regular pattern of the three lepton and quark families is one of the most intriguing puzzles in particle physics. The existence of families gives rise to many of the free parameters in the SM, including the fermion masses, and the elements of the CKM matrix.

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Enumerating Abelian Typical Cube-Free Fold Coverings of a Circulant Graph

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Algebra Colloquium 2020年第1期27卷 137-148页

作者： young Soo kwon Jaeun Lee Department of Mathematics Yeungnam UniversityKyongsan712-749Korea

Enumerating the isomorphism or equivalence classes of several types of graph coverings is one of the central research topics in enumerative topological graph theory.A covering projection p from a Cayley graph Cay(Г,X)onto another Cayley graph Cay(Q,y)is called typical if the function p:Г→Q on the vertex sets is a group epimorphism.A typical covering is called abelian(or circulant,respectively)if its covering graph is a Cayley graph on an abelism(or a cyclic,respectively)***,the equivalence classes of connected abelian typical prime-fold coverings of a circulant graph are *** a continuation of this work,we enumerate the equivalence classes of connected abelian typical cube-free fold coverings of a circulant graph.

关键词： graph covering enumeration voltage assignment circulant graph

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Introduction

Introduction

Controlled multilevel switching and artificial synapse characteristics in transparent HfAlo-alloy based memristor with embedded TaN nanoparticles

Photonics Asia 2004;Sensors and Imaging

作者： osuk y.kwon

These proceedings contain the papers presented at the Photonics Asia 2004 Advanced Sensors Systems and Applications conference, held 8-12 November 2004, in Beijing, China. This conference covered a number of key issues concerning recent progress in advanced sensors and their applications, in particular optical fiber sensors. After more than 20 years, worldwide research and development in the field of optical fiber sensors is still very active. This conference had many more papers submitted than that held two years ago. This strong growth may be due to significant reductions in the cost of most fiber optic components and the maturity of optical fiber sensors, such as fiber grating sensors and interferometric sensors.

关键词： Introduction

来源： cnki会议评论

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Journal of Materials Science & Technology 2021年第36期95卷 203-212页

作者： Chandreswar Mahata Hassan Algadi Muhammad Ismail Daewoong kwon Sungjun Kim Division of Electronics and Electrical Engineering Dongguk UniversitySeoul 04620Republic of Korea Department of Electrical Engineering Faculty of EngineeringNajran UniversityP.O.Box 1988Najran 11001Saudi Arabia Department of Electrical Engineering Inha UniversityIncheonRepublic of Korea

Atomic layer deposition technique has been used to prepare tantalum nitride nanoparticles(TaN-NPs)and sandwiched between Al-doped Hfo;layers to achieve ITo/HfAlo/TaN-NP/HfAlo/ITo RRAM *** electron microscopy along with energy dispersive spectroscopy confirms the presence of TaN-NPs.X-ray photoelectron spectroscopy suggests that part of Ta N converted to tantalum oxynitride(Tao_(x)N_(y))which plays an important role in stable cycle-to-cycle resistive *** trapping and oxygen vacancy creation were found to be modified after the inclusion of Ta N-NPs inside RRAM ***,HfAlo/Tao_(x)N_(y)interface due to the presence TaN-NPs improves the device-to-device switching reliability by reducing the probability of random rupture/formation of conductive filaments(CFs).DC endurance of more than 10^(3)cycles and memory data retention up to 10^(4)s was achieved with an insignificant variation of different resistance *** conductance was attained by controlling RESET voltage with stable data retention in multiple *** volatile threshold switching was monitored after controlling the CF forming at 200 nA current compliance with high selectivity of~10^(3).Synaptic learning behavior has been demonstrated by spike-rate-dependent plasticity(SRDP).Reliable potentiation and depression processes were observed after the application of suitable negative and positive pulses which shows the capability of the TaN–NPs based RRAM device for transparent synaptic devices.

关键词： RRAM ALD TaN-nanoparticles Threshold switching Spike-rate-dependent plasticity Multilevel conductance Synaptic properties

4-1BB signaling activates glucose and fatty acid metabolism to enhance CD8^(+) T cell proliferation

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Cellular & Molecular Immunology 2017年第9期14卷 748-757页

作者： Beom K Choi Do y Lee Don G Lee young H Kim Seon-Hee Kim Ho S oh Chungyong Han Byoung S kwon Cancer Immunology Branch Division of Cancer BiologyNational Cancer CenterGoyangGyeonggi 10408Korea Department of Internal Medicine Yonsei University College of MedicineSeoul 120-752Korea Immune Cell Production Unit Program for Immunotherapeutic ResearchNational Cancer CenterGyeonggi 10408Korea Eutilex Catholic University School of MedicineSeoul 06591Korea Department of Medicine Tulane University Health Sciences CenterNew OrleansLA 70112USA

4-1BB(CD137)is a strong enhancer of the proliferation of CD8^(+)T *** these cells require increased production of energy and biomass to support their proliferation,we hypothesized that 4-1BB signaling activated glucose and fatty acid *** found that treatment with agonistic anti-4-1BB mAb promoted the proliferation of CD8^(+)T cells in vitro,increasing their size and *** with a glycolysis inhibitor and a fatty acid oxidation inhibitor revealed that CD8^(+)T cell proliferation required both glucose and fatty acid ***-4-1BB treatment increased glucose transporter 1 expression and activated the liver kinase B1(LKB1)-AMP-activated protein kinase(AMPK)-acetyl-CoA carboxylase(ACC)signaling pathway,which may be responsible for activating the metabolism of glucose and fatty *** also examined whether blocking glucose or fatty acid metabolism affected cell cycle progression and the anti-apoptotic effect of 4-1BB *** increase of anti-apoptotic factors and cyclins in response to anti-4-1BB treatment was completely prevented by treating CD8^(+)T cells with the fatty acid oxidation inhibitor,etomoxir,but not with the glycolysis inhibitor,*** conclude that anti-4-1BB treatment activates glucose and fatty acid metabolism thus supporting the increased demand for energy and biomass,and that fatty acid metabolism plays a crucial role in enhancing the cell cycle progression of anti-CD3-activated CD8^(+)T cells in vitro and the anti-apoptotic effects of 4-1BB signaling on these cells.

关键词： AMPK CD8^(+)T cells 4-1BB(CD137) LKB1 metabolism

Endoplasmic reticulum stress-induced accumulation of VAMP721/722 requires CALRETICULIN 1 and CALRETICULIN 2 in Arabidopsis

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Journal of Integrative Plant Biology 2019年第9期61卷 974-980页

作者： Soohong Kim yunjin Choi Chian kwon Hye Sup yun Department of Molecular Biology Dankook UniversityCheonan 31116Korea Department of Biological Sciences Konkuk UniversitySeoul 05029Korea

Excessive demand for translation and protein folding in the endoplasmic reticulum(ER) can cause ER stress in plants. Here, we show that CALRETICULIN 1(CRT1) and CRT2 are critical components in the accumulation of VESICLE-ASSoCIATED MEMBRANE PRoTEIN 721(VAMP721) and VAMP722 during ER stress responses. We show that CRT2 interacts with VAMP722 and that CRT1/2 post-translationally maintain elevated VAMP721/722 levels under ER *** greater growth inhibition in VAMP721/722-deficient plants, induced by tunicamycin, suggests that plants under ER stress maintain physiological homeostasis, at least in part, by regulating VAMP721/722 levels, as VAMP721/722 are known to participate in various biological processes.

关键词： Endoplasmic reticulum VAMP721/722 in Arabidopsis