Synthesis of Dihydrofuranoquinophenoxazine Analogues as New Antitumor Agents

Younghwa Na 대한화학회 2005 Bulletin of the Korean Chemical Society Vol.26 No.12

Plasma start-up design and first plasma experiment in VEST

An, YoungHwa,Lee, Jeongwon,Lee, HyunYeong,Jo, JongGab,Jung, Bong-Ki,Chung, Kyoung-Jae,Kim, Young-Gi,Jo, Jungmin,Yang, Jeong-hun,Na, Yong-Su,Hahm, T.S.,Hwang, Y.S. Elsevier 2015 Fusion engineering and design Vol.96 No.-

<P><B>Abstract</B></P> <P>First plasma start-up experiment in Versatile Experiment Spherical Torus (VEST) has been successfully carried out with conventional start-up scheme using a central solenoid. A start-up design code has been developed for the development of start-up scenarios in VEST, which can predict evolutions of vacuum field structure and plasma current with given operation parameters from the PF coil power supply circuit considering the eddy currents. Start-up scenarios are successfully developed with the code, generating field null region in the inboard side at the onset of loop voltage in order to maximize the connection length, and then providing the required poloidal magnetic field for stable equilibrium as the plasma current evolves. Hydrogen is used as a working gas and the toroidal field of 0.1T with 0.2s flat-top is applied on magnetic axis during the discharge. With the assist of ECH (Electron Cyclotron Heating) pre-ionization (6kW, 2.45GHz), a plasma current of ∼70kA has been generated with the pulse duration of ∼10ms. The elongation and edge safety factor are estimated to be 1.6 and 3.7 respectively.</P> <P><B>Highlights</B></P> <P> <UL> <LI> First plasma start-up experiment in VEST has been successfully carried out. </LI> <LI> A start-up design code is developed to generate start-up scenarios in predictive manner. </LI> <LI> Start-up scenarios are developed with the code and confirmed experimentally in VEST. </LI> <LI> Full tokamak equilibria (<I>I</I> <SUB> <I>p</I> </SUB> =70kA, <I>κ</I> =1.6 and <I>q</I> <SUB>edge</SUB> =3.7) are achieved from the scenario. </LI> </UL> </P>

Efficient ECH-assisted plasma start-up using trapped particle configuration in the versatile experiment spherical torus

An, YoungHwa,Lee, Jeongwon,Jo, JongGab,Jung, Bong-Ki,Lee, HyunYeong,Chung, Kyoung-Jae,Na, Yong-Su,Hahm, T.S.,Hwang, Y.S. IOP 2017 Nuclear fusion. Fusion nucléaire. &n.Illiga Vol.57 No.1

<P>An efficient and robust ECH (electron cyclotron heating)-assisted plasma start-up scheme with a low loop voltage and low volt-second consumption utilizing the trapped particle configuration (TPC) has been developed in the versatile experiment spherical torus (VEST). The TPC is a mirror-like magnetic field configuration providing a vertical magnetic field in the same direction as the equilibrium field. It significantly enhances ECH pre-ionization with enhanced particle confinement due to its mirror effect, and intrinsically provides an equilibrium field with a stable decay index enabling prompt plasma current initiation. Consequently, the formation of TPC before the onset of the loop voltage allows the plasma to start up with a lower loop voltage and lower volt-second consumption as well as a wider operation range in terms of ECH pre-ionization power and H<SUB>2</SUB> filling pressure. The TPC can improve the widely-used field null configuration significantly for more efficient start-up when ECH pre-ionization is used. This can then be utilized in superconducting tokamaks requiring a low loop voltage start-up, such as ITER, or in spherical tori with limited volt-seconds. The TPC can be particularly useful in superconducting tokamaks with a limited current slew-rate of superconducting PF coils, as it can save volt-second consumption before plasma current initiation by providing prompt initiation with an intrinsic stable equilibrium field.</P>

고속도로 요금소 요금 수납원 직무스트레스에 관한 연구

나정연(JeongYeon Na),권민지(Minji Kwon),김두영(DooYoung Kim),박영화(YoungHwa Park),서정은(JungEun Seo),신민철(MinCheol Shin),김희지(HeeJi Kim),김화일(HwaIl Kim),류향우(Hyangwoo Ryu),조만수(ManSu Cho) 한국환경보건학회 2017 한국환경보건학회지 Vol.43 No.5

Objectives: The rate at which the nationwide highway is outsourcing the duties of toll gate cashiers to the public is increasing. The aim of this study is to conduct research on job stress for the rate at which the fares are collected by national highway toll gate cashiers. Methods: The population selected was a statistically significant group making up 10% of the total number of people surveyed in 2015, with a population of approximately 5,495 persons. The sample size is intended to cover the maximum sample size of 550 samples and the maximum number of samples that should be obtained. After allocating the number of samples by quota allocation, the qualitative function of Quality Function Deployment (QFD) was applied by random sampling. Results: Job stress ranked at 46.6 ± 11.5 points was found to be under the stress of 50% reported in other occupations. Job stress items showed higher for “job instability” compared to other types of tasks. Also, it appeared lower in “conflict in relationships.” This is a result of the work characteristics of highway service operators. Conclusions: Time was found to have the highest influence on the workload (β = 0.80, p. 0.001), which calls for a reduction in time and workload. est influence on the workload (β = 0.80, p. 0.001), which requires a reduction in time and workload.

Design and development of the helicity injection system in Versatile Experiment Spherical Torus

Park, JongYoon,An, Younghwa,Jung, Bongki,Lee, Jeongwon,Lee, HyunYoung,Chung, Kyoung-Jae,Na, Yong-Su,Hwang, Y.S. Elsevier 2015 Fusion engineering and design Vol.96 No.-

<P><B>Abstract</B></P> <P>A helicity injection system for the Versatile Experiment Spherical Torus (VEST) has been successfully developed and commissioned. A high current electron gun utilizing hollow cathode and washer stacks has been designed and constructed with a single pulse power system that can provide voltages for both arc discharge and extraction sequentially. Tests for electron gun operation with the single pulse power system have been conducted under various toroidal and poloidal field strengths. The estimated plasma impedance, depending on the injection magnetic field structure, can be utilized for the optimal gun operation by impedance matching between the pulse power system and plasma. With the charging voltage of 1.2kV, injection current of 0.95kA has been obtained with the injection voltage of 410V for about 5ms. Initial helicity injection experiments have been conducted under various toroidal and poloidal field strengths and a toroidal plasma current of up to 3.8kA is observed with the current multiplication larger than the geometric stacking ratio, confirming the possibility of relaxation into tokamak-like plasma with closed flux formation.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A high current electron gun with single pulse power for both arc and extraction is developed. </LI> <LI> The optimal gun operation is confirmed by impedance matching between the PFN and plasma. </LI> <LI> The gun injected currents of 0.95kA with the voltage of ∼410V for 5ms with a 1.2kV PFN. </LI> <LI> The helicity injection system using the gun has been developed and tested successfully in VEST. </LI> <LI> Toroidal currents of up to 3.8kA confirm possible relaxation into tokamak-like plasma. </LI> </UL> </P>

[6]-Gingerol prevents UVB-induced ROS production and COX-2 expression in vitro and in vivo

Kim, Jin-Kyoung,Kim, Younghwa,Na, Kwang-Min,Surh, Young-Joon,Kim, Tae-Yoon Harwood Academic 2007 Free radical research Vol.41 No.5

<P> [6]-Gingerol, a naturally occurring plant phenol, is one of the major components of fresh ginger (Zingiber officinale Roscoe, Zingiberaceae) and has diverse pharmacologic effects. Here, we describe its novel anti-oxidant, anti-apoptotic, and anti-inflammatory activities in vitro and in vivo. In vitro, pre-treatment with [6]-gingerol reduced UVB-induced intracellular reactive oxygen species levels, activation of caspase-3, -8, -9, and Fas expression. It also reduced UVB-induced expression and transactivation of COX-2. Translocation of NF-&kgr;B from cytosol to nucleus in HaCaT cells was inhibited by [6]-gingerol via suppression of I&kgr;Bα phosphorylation (ser-32). Examination by EMSAs and immunohistochemistry showed that topical application of [6]-gingerol (30 μM) prior to UVB irradiation (5 kJ/m2) of hairless mice, also inhibited the induction of COX-2 mRNA and protein, as well as NF-&kgr;B translocation. These results suggest that [6]-gingerol could be an effective therapeutic agent providing protection against UVB-induced skin disorders.</P>

The synthesis and anticancer activities of chiral epoxy-substituted chromone analogs

Jo, Hyunji,Hee Seo, Seung,Na, Younghwa,Kwon, Youngjoo Elsevier 2019 Bioorganic chemistry Vol.84 No.-

<P><B>Abstract</B></P> <P>Human DNA topoisomerases (topos) have been recognized as a good target molecule for the development of anticancer drugs because they play an important role in solving DNA topological problems caused by DNA strand separation during replication and transcription. In this study, we designed and synthesized 11 novel chromone backbone compounds possessing epoxy and halohydrin substituents with chirality. In the topos inhibition test, compounds <B>2</B>, <B>9</B>, <B>10</B>, and <B>11</B> showed comparable topo I inhibitory activity at concentration of 100 μM compared to camptothecin, and all of the synthesized compounds showed moderate topo IIα inhibitory activity. Among them, compounds <B>9</B>, <B>10</B> and <B>11</B> were more potent than the others in both topo I and IIα inhibitory activity. Compound <B>11</B> showed the most potent cell antiproliferative activity against all tested cancer cell lines with particularly strong inhibition (an IC<SUB>50</SUB> of 0.04 µM) of K562 myelogenous leukemia cancer cell proliferation. In the brief structure-activity relationship analysis, there was no clear correlation between stereochemistry and topos inhibitory and cytotoxic activity. 5(<I>R</I>),7(<I>S</I>)-bisepoxy-substituted compound <B>11</B> was the most potent DNA cross-linker and induced G2/M arrest in a cell cycle assay in a dose- and time-dependent manner. After the treatment time period induced apoptosis in K562 cells without increasing G2/M-phase cells. Overall, compound <B>11</B> showed good consistent inhibitory biological activity related to cancer cell proliferation.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Compound <B>11</B> showed comparable topo I inhibitory activity (61.2%) at 100 µM compared to camptothecin. </LI> <LI> Compound <B>11</B> showed comparable topo IIα inhibitory activity (41.5%) at 100 µM compared to etoposide. </LI> <LI> Cytotoxic IC<SUB>50</SUB> (µM) of compound <B>11</B> to K562 cancer cell was 0.04 ± 0.03. </LI> <LI> Compound <B>11</B> was excellent DNA-cross-linking agent. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Development of equilibrium fitting code using finite element method in versatile experiment spherical torus

Lee, Jeongwon,Kim, SeongCheol,Park, JongYoon,Kim, Young-Gi,An, YoungHwa,Yoo, Min-Gu,Yang, Jeong-hun,Chung, Kyoung-Jae,Hwang, Y.S.,Na, Yong-Su Elsevier 2018 Fusion engineering and design Vol.131 No.-

<P><B>Abstract</B></P> <P>An equilibrium fitting code using finite element method is developed for various plasma studies, especially on non-inductive start-up and ECH heating & current drive experiments in Versatile Experiment Spherical Torus. The magnetic diagnostics are applied to provide the basic equilibrium fitting constraints. As severe eddy currents are induced by not only the PF coils but also the plasma current itself, the eddy current component from the magnetic signals is dealt with the vessel wall model in the eddy current solver and carefully compensated, which is essential for accurate equilibrium fitting. The fast camera image analysis method is adopted and the limiter current monitoring system is developed for validating the results of the plasma position and shape from the code. The equilibrium fitting code is applied to the limited and diverted plasma configuration in VEST and the time evolution of the plasma position and shape and even averaged magnetohydrodynamic parameters such as the edge safety factor and the internal inductance are extracted. Additionally, the equilibrium fitting code is used to analyze the non-inductive plasma start-up experiment using the direct current helicity injection in VEST. Especially, it is the first time to apply the finite element method to direct current helicity injection experiment and ECH heated plasmas which have significant amount of plasma current flowing along the open field line.</P>

IICT 기반 스마트팜을 위한 온실 환경 제어 알고리즘 설계

양미혜 ( Mi-hye Yang ),남원호 ( Won-ho Nam ),방나경 ( Na-kyoung Bang ),황재용 ( Jaeyong Hwang ),이관호 ( Kwanho Lee ),김영화 ( Younghwa Kim ) 한국농공학회 2018 한국농공학회 학술대회초록집 Vol.2018 No.-

최근 국내 농업은 농업인구의 감소 및 고령화, 농가소득의 감소, 농산물 수입 개방 심화 등으로 어려움을 겪고 있어 ICT 기술의 융복합을 기반으로 농작물을 재배하는 스마트팜을 도입하여 생산성과 품질을 향상시키고자 한다. 스마트팜기술은 유럽의 농업 선진국에서 최근 급속히 발전하고 있으며, 특히 네덜란드의 시설농업은 대규모 유리온실을 효율적으로 운영하는데 적합한 기술을 보유하고 있다. 그러나 국내 시설농업은 대부분 중소규모 단동 비닐온실에서 이루어지고 있어 유리온실에 적합한 농업 선진국의 스마트팜 기술을 국내 시설 재배에 적용하기에는 구조적 측면뿐만 아니라 경제적 측면에서도 적합하지 않다. 따라서 비닐하우스 위주의 국내 시설재배 특성에 맞도록 축적된 노하우와 품목별 재배여건 등을 고려한 ICT 기반 한국형 스마트팜의 개발이 필요하다. 따라서 본 연구에서는 이러한 한국형 스마트팜 개발을 위한 온실 환경 제어 알고리즘을 설계하고자 한다. 온실 환경변수는 작물이 생장하는데 필수 요소인 온도, 이산화탄소, 양액, 습도이며 온실 환경을 자동으로 제어하기 위한 각각의 알고리즘을 설계하였다. 본 연구의 결과는 향후 고용노동력을 최소화하면서 비닐온실이 주를 이루고 있는 국내 시설농업의 농산물 생산에 최적화된 환경을 제공함으로서 고품질 농산물 생산에 도움을 줄 수 있을 것으로 판단된다.

Synthesis and investigation of dihydroxychalcones as calpain and cathepsin inhibitors

( Kyung Hye Baek ),( Radha Karki ),( Eung Seok Lee ),( Younghwa Na ),( Youngjoo Kwon ) 영남대학교 약품개발연구소 2014 영남대학교 약품개발연구소 연구업적집 Vol.24 No.0

In order to identify potential calpain and cathepsin inhibitors we prepared 12 dihydroxychalcone analogues and tested their ability to inhibit μ-calpain, m-calpain, cathepsins B and L. In the calpain inhibition test, compound 10 exhibited the most active inhibitory activity against m-calpain with an IC50 value of 25.25±0.901μM. With respect to inhibition of cathepsins B and L, compound 13 exhibited the most potent inhibitory activity on cathepsin L and moderate inhibitory activity on cathepsin B with IC50 values of 2.80±0.100 and 11.47±0.087μM, respectively. Our results suggest the possibility of developing dual calpain and cathepsin inhibitors by properly modulating structures and/or combining the essential aspects of the functional group effective for specific calpain and cathepsin inhibition. ⓒ2013 Elsevier Inc. All rights reserved.