Key Features in the Operation of KSTAR

Jong-Gu Kwak,Oh, Y. K.,Kim, K. P.,Kim, S. W.,Hong, S. H.,Chu, Y.,Lee, H. J.,Kim, Y. O.,Kim, J.,Park, S. L.,Hahn, S. H.,Park, M. K.,Kim, H. K.,Bak, J. G.,Bae, Y. S.,Ko, W. H.,Lee, S. G.,Lee, J. H.,Jung IEEE 2012 IEEE transactions on plasma science Vol.40 No.3

<P>The Korea Superconducting Tokamak Advanced Research (KSTAR) device is aimed at advanced tokamak (AT) research. Three years have passed since it achieved its first plasma in 2008. Because it is a superconducting machine and is working toward AT research, it has unique features in terms of the machine engineering and operation. The toroidal field (TF) magnet coils are made of Nb<SUB>3</SUB>Sn, which provide high TFs up to 3.5 T, and have been fully tested. The poloidal field (PF) magnet coils, consisting of both Nb<SUB>3</SUB>Sn and NbTi, which have a maximum current of 25 kA in their design, were tested up to 15 kA. A thermal hydraulic analysis is being conducted for PF magnet coil operation. All plasma-facing components (PFCs) are equipped with water cooled graphite tiles and have the capability of being baked up to 350°C. A startup scenario, which considered both the effect of the ferromagnetic material in the cable in conduit conductor jacket of the magnet coils as well as a nonferromagnetic up-down asymmetry in the cryostat structure, was developed and demonstrated its effectiveness by the last two year's reliable operations. Passive stabilizers and in-vessel control coils (IVCCs) are key components to realize AT operation in KSTAR. The segmented IVCC coils were connected to form circular coils for internal vertical control in 2010, and diverted plasmas with high elongation (κ~1.8, δ>;0.6) were achieved. A neutral beam injection (NBI) system was developed aiming at 2 MW, 300 s per ion source which meets the long-pulse requirement of KSTAR. An NBI ion source with a power of 1.7 MW at 100 kV has been commissioned for 10 s. Finally, ELMy H-modes were successfully produced with 1.3-MW NBI power at a plasma current of 0.6 MA in the 2010 campaign. The first H-mode discharge (#4200) in KSTAR was achieved one year earlier than officially planned and was done at B<SUB>T</SUB> = 2 T with I<SUB>p</SUB> = 0.6 MA in a well-balanced double null configuration after boronization on the PFC. Successful operations in the early days of KSTAR including H-mode experiments revealed the capability of advanced and steady-state operation which is essential for the international thermonuclear experimental reactor (ITER) and future fusion reactors.</P>

Development of Bovine Specific Leptin Radioimmunoassay and Relationship of Plasma Leptin with Vitamin A and Age of Wagyu

Yang, S.H.,Kawachi, H.,Khan, M.A.,Lee, S.Y.,Kim, H.S.,Ha, Jong K.,Lee, W.S.,Lee, H.J.,Ki, K.S.,Kim, S.B.,Sakaguchi, S.,Maruyama, S.,Yano, H. Asian Australasian Association of Animal Productio 2008 Animal Bioscience Vol.21 No.9

Leptin is produced by adipocytes and its role in the regulation of lipid metabolism, feed intake, productive and reproductive performance of domestic animal species has been greatly stressed and extensively investigated in recent years. This study was conducted to develop a radioimmunoassay (RIA) for the estimation of plasma bovine leptin and to determine plasma leptin concentration in fattening Japanese Black cattle (Wagyu) and its crossbreds at commercial farms. Relationships of plasma leptin with plasma vitamin A and age of crossbred cattle were also determined. Recombinant bovine leptin (rbleptin) was produced by the E. coli overexpressed leptin as a GST (glutathione S-transferase)-fusion protein. Then antiserum against bovine leptin was obtained by its immunization in rabbits. Using this antiserum, a bovine specific RIA was developed and plasma leptin level was determined in 120 crossbred fattening cattle (WagyuHolstein, 50:50) at commercial farms. The plasma leptin level increased with the age of cattle and its level was greater in the crossbred heifers than in the steers. Plasma vitamin A level was negatively correlated with plasma leptin level in crossbred heifers and steers. This relationship was stronger in heifers than in steers. Plasma leptin was gradually increased with advancing age in fattening Wagyu cattle. In conclusion, development of a bovine specific RIA to estimate plasma leptin will contribute to better understanding of the role of leptin in cattle.

Clinical Significance of Chronic Kidney Disease and Atrial Fibrillation on Morbidity and Mortality in Patients with Acute Myocardial Infarction

Hwang, Hyeon Seok,Park, Mahn-Won,Yoon, Hye Eun,Chang, Yoon Kyung,Yang, Chul Woo,Kim, Suk Young,Cho, Jung Sun,Kim, Chan Joon,Park, Gyung-Min,Park, Chul-Soo,Choi, Yun-Seok,Koh, Yoon-Seok,Lee, Jong Min,S S. Karger AG 2014 American journal of nephrology Vol.40 No.4

<P>Abstract</P><P><B><I>Background/Aims:</I></B> Atrial fibrillation (AF) often coexists with acute myocardial infarction (AMI), and chronic kidney disease (CKD) is a major risk for AMI. However, the combined impact of CKD and AF on the mortality and morbidity in AMI population has not been determined. <B><I>Methods:</I></B> Between January 2004 and December 2009, a total of 4,738 AMI patients were enrolled prospectively. Patients were divided into four groups according to the combined status of CKD and AF. The primary endpoint was a combination of 5-year major adverse cardiac and cerebrovascular events (MACCE). <B><I>Results:</I></B> The prevalence of AF was significantly higher in CKD patients than in non-CKD patients (6.76 vs. 3.31%, p < 0.001). The highest cumulative event rate of MACCE and death was observed in patients with both CKD and AF (68.5 and 64.0%), respectively. In multivariable analyses, compared with patients with neither AF nor CKD, hazard ratios (HR) for composite of MACCE were 1.66 (95% CI, 1.14-2.41), 1.24 (95% CI, 1.06-1.46), and 2.10 (95% CI, 1.42-3.13) for patients with AF only, those with CKD only, and those with both CKD and AF, respectively (p for interaction = 0.935). Patients with both CKD and AF had a greatest risk for all-cause mortality (HR 2.54; 95% CI, 1.60-4.53), and the significant synergistic interaction was observed between CKD and AF (p for interaction = 0.015). <B><I>Conclusion:</I></B> The combined effect of AF and CKD on the risk of MACCE after an AMI is stronger than any separate condition, and it confers a synergistic effect on the all-cause mortality risk.</P><P>© 2014 S. Karger AG, Basel</P>

The effects of topical mesenchymal stem cell transplantation in canine experimental cutaneous wounds

Kim, Ju-Won,Lee, Jong-Hwan,Lyoo, Young S,Jung, Dong-In,Park, Hee-Myung Blackwell Publishing Ltd 2013 Veterinary dermatology Vol.24 No.2

<P><B>Background</B></P><P>Adult stem cells have been widely investigated in bioengineering approaches for tissue repair therapy. We evaluated the clinical value and safety of the application of cultured bone marrow-derived allogenic mesenchymal stem cells (MSCs) for treating skin wounds in a canine model.</P><P><B>Hypothesis</B></P><P>Topical allogenic MSC transplantation can accelerate the closure of experimental full-thickness cutaneous wounds and attenuate local inflammation.</P><P><B>Animals</B></P><P>Adult healthy beagle dogs (<I>n</I> = 10; 3–6 years old; 7.2–13.1 kg) were studied.</P><P><B>Methods</B></P><P>Full-thickness skin wounds were created on the dorsum of healthy beagles, and allogenic MSCs were injected intradermally. The rate of wound closure and the degree of collagen production were analysed histologically using haematoxylin and eosin staining and trichrome staining. The degree of cellular proliferation and angiogenesis was evaluated by immunocytochemistry using proliferating cell nuclear antigen-, vimentin- and α-smooth muscle actin-specific antibodies. Local mRNA expression levels of interleukin-2, interferon-γ, basic fibroblast growth factor and matrix metalloproteinase-2 were evaluated by RT-PCR.</P><P><B>Results</B></P><P>Compared with the vehicle-treated wounds, MSC-treated wounds showed more rapid wound closure and increased collagen synthesis, cellular proliferation and angiogenesis. Moreover, MSC-treated wounds showed decreased expression of pro-inflammatory cytokines (interleukin-2 and interferon-γ) and wound healing-related factors (basic fibroblast growth factor and matrix metalloproteinase-2).</P><P><B>Conclusion and clinical importance</B></P><P>Topical transplantation of MSCs results in paracrine effects on cellular proliferation and angiogenesis, as well as modulation of local mRNA expression of several factors related to cutaneous wound healing.</P><P><B>Résumé</B></P><P><B>Contexte</B></P><P>Les cellules souches adultes ont été largement étudiées dans les approches de bio-ingénierie pour la thérapie de réparation tissulaire. Nous évaluons l'efficacité clinique et la sécurité de l'application de cellules souches mésenchymateuses allogéniques en culture dérivées de moelle osseuse (MSCs) pour le traitement de plaies cutanées dans un modèle canin.</P><P><B>Hypothèse</B></P><P>La transplantation de MSC allogénique topique peut accélérer la fermeture en toute épaisseur de plaies cutanées expérimentales et atténuer l'inflammation locale.</P><P><B>Sujets</B></P><P>Des chiens beagles adultes sains (<I>n</I> = 10; 3–6 ans; 7.2–13.1 kg) ont été étudiés.</P><P><B>Méthodes</B></P><P>Des plaies cutanées en pleine épaisseur ont été crées sur la face dorsale des beagles sains et des MSCs allogènes ont été injectées par voie intradermique. Le taux de cicatrisation et le degré de production de collagène ont été analysés sur le plan histologique par colorations à l'hématoxyline et éosine et par trichrome. Le degré de prolifération cellulaire et d'angiogénèse ont été évalués par immunohistochimie à l'aide d'anticorps spécifiques d'antigène nucléaire de prolifération cellulaire, de vimentine et d'actine de muscle lisse α. Les taux d'expression local d'ARNm d'interleukine-2, d'interféron-γ, du facteur de croissance basique de fibroblaste et de métalloprotéinase-2 de matrice, ont été évalués par RT-PCR.</P><P><B>Résultats</B></P><P>Comparé avec les plaies traité

Lateral Thalamic Infarction and the Vascular Geometry of the Posterior Cerebral Artery

Kim, Bum Joon,Kim, Seung Min,Ahn, Sung-ho,Kang, Dong-Wha,Kwon, Sun U.,Kim, Jong S. S. Karger AG 2016 Cerebrovascular Diseases Vol.41 No.1

<P>Background: The geometric properties of the parental artery affect the development of local atherosclerosis and perforator infarction. In this study, we aimed at investigating the association between vascular geometry of the posterior cerebral artery (PCA) and the development of isolated lateral thalamic infarction (LTI), the most frequent type of thalamic infarction. Methods: The geometric properties of the corresponding PCA in LTI patients were assessed and they include the diameters of the distal basilar artery (BA) and proximal PCA, distal BA - PCA angle, first PCA angle (angle between P1 and P2), and the presence of the posterior communicating artery (Pcom). These parameters obtained from the ipsilesional PCA were compared with the contralesional PCA and the corresponding PCA in age-and sex-matched controls. Results: Forty-five LTI patients were enrolled. The ipsilesional PCA in LTI patients demonstrated a greater ipsilesional P1 - P2 angle (81.4 +/- 22.6 vs. 71.3 +/- 23.2 degrees, respectively; p = 0.04) and a higher prevalence of Pcom (42.2 vs. 13.3%; p = 0.002) when compared to control subjects. In comparison with the contralesional PCA, ipsilesional PCA demonstrated a smaller diameter, larger angle between P1 and P2 segment, and a higher prevalence of Pcom. The presence of hyperlipidemia (OR 3.548 (1.283-9.811); p = 0.02) and Pcom (OR 3.507 (1.104-11.135); p = 0.03) was a factor that was independently associated with LTI. Conclusions: Local hemodynamics in the PCA may be influenced by the P1 - P2 angle and the presence of Pcom, which are associated with the development of LTI. (C) 2015 S. Karger AG, Basel</P>

Directional dependence via Gaussian copula beta regression model with asymmetric GARCH marginals

Kim, Jong-Min,Hwang, S.Y. Informa UK (TaylorFrancis) 2017 Communications in statistics Simulation and comput Vol.46 No.10

<P>This article proposes a new directional dependence by using the Gaussian copula beta regression model. In particular, we consider an asymmetric Generalized AutoRegressive Conditional Heteroscedasticity (GARCH) model for the marginal distribution of standardized residuals to make data exhibiting conditionally heteroscedasticity to white noise process. With the simulated data generated by an asymmetric bivariate copula, we verify our proposed directional dependence method. For the multivariate direction dependence by using the Gaussian copula beta regression model, we employ a three-dimensional archemedian copula to generate trivariate data and then show the directional dependence for one random variable given two other random variables. With West Texas Intermediate Daily Price (WTI) and the Standard & Poor's 500 (S&P 500), our proposed directional dependence by the Gaussian copula beta regression model reveals that the directional dependence from WTI to S&P 500 is greater than that from S&P 500 to WTI. To validate our empirical result, the Granger causality test is conducted, confirming the same result produced by our method.</P>

Development of Cerebral Infarction Shortly after Intracerebral Hemorrhage

Kim, Chul H.,Kim, Jong S. S. Karger AG 2007 European neurology Vol.57 No.3

<P><I>Background and Purpose:</I> Cerebral infarction (CI) occurring soon after intracerebral hemorrhage (ICH) has been rarely reported. The purpose of the present study was to characterize this condition and discuss the possible pathophysiology. <I>Method:</I> We retrospectively studied 6 patients who developed CI within 10 days after the onset of ICH. <I>Results:</I> The initial ICHs were located in the putamen (n = 3), thalamus (n = 2) and cerebellum (n = 1), and were considered to be caused by hypertension in all of the patients. They showed sudden worsening (n = 4) or change in neurologic symptoms (n = 2) within 10 days after the initial ICH. Follow-up imaging revealed corresponding lacunar (n = 2) and territorial (n = 4) infarcts. Possible factors related to the development of new CIs included mechanical compression of cerebral vessels (n = 2), dehydration (n = 4), hypotension (n = 2), infection (n = 2) and concomitant small-vessel pathology (n = 2). <I>Conclusions:</I> ICH may predispose certain patients to the development of infarcts through a combination of mechanisms, including mechanical compression of cerebral vessels, hemodynamic instability, inflammation and concomitant small-vessel pathology.</P><P>Copyright © 2007 S. Karger AG, Basel</P>

Transcortical Sensory Aphasia after Left Frontal Lobe Infarction: Loss of Functional Connectivity

Kwon, Miseon,Shim, Woo Hyun,Kim, Sang-Joon,Kim, Jong S. S.Karger 2017 European neurology Vol.78 No.1

<P>Background: The underlying mechanism of transcortical sensory aphasia (TSA) caused by lesions occurring in the left frontal lobe remains unclear. We attempted to investigate the mechanism with the use of functional MRI (fMRI). Methods: We studied 2 patients with TSA after a left frontal infarction identified by diffusion-weighted MRI. As control subjects, a patient with transcortical motor aphasia and a healthy normal adult were chosen. The Korean version of Western Aphasia Battery was performed initially and at 3 months post stroke. We performed fMRI using verb generation and sentence completion tasks. Resting-state fMRI (rs-fMRI) was also obtained for network-level analysis initially and at 3 months post stroke. Results: The results of diffusion- and perfusion-weighted MRI revealed no diffusion-perfusion mismatch. Initial fMRI in patients with TSA showed no reversed inter-/intrahemispheric activation patterns. rs=fMRI showed significantly decreased resting-state functional connectivity in the language network in patients with TSA compared with the control subjects. Follow-up rs-fMRI studies showed improvement in functional connectivity along with the recovery of patients' language function. Conclusion: Our data showed that the auditory comprehension deficits in patients with frontal lobe infarcts is attributed to difficulty accessing the posterior language area due to functional disconnection between language centers in the acute stage of stroke. (C) 2017 S. Karger AG, Basel</P>

Large-scale pattern growth of graphene films for stretchable transparent electrodes

Kim, Keun Soo,Zhao, Yue,Jang, Houk,Lee, Sang Yoon,Kim, Jong Min,Kim, Kwang S.,Ahn, Jong-Hyun,Kim, Philip,Choi, Jae-Young,Hong, Byung Hee Macmillan Publishers Limited. All rights reserved 2009 Nature Vol.457 No.7230

Problems associated with large-scale pattern growth of graphene constitute one of the main obstacles to using this material in device applications. Recently, macroscopic-scale graphene films were prepared by two-dimensional assembly of graphene sheets chemically derived from graphite crystals and graphene oxides. However, the sheet resistance of these films was found to be much larger than theoretically expected values. Here we report the direct synthesis of large-scale graphene films using chemical vapour deposition on thin nickel layers, and present two different methods of patterning the films and transferring them to arbitrary substrates. The transferred graphene films show very low sheet resistance of ∼280 Ω per square, with ∼80 per cent optical transparency. At low temperatures, the monolayers transferred to silicon dioxide substrates show electron mobility greater than 3,700 cm<SUP>2</SUP> V<SUP>-1</SUP> s<SUP>-1</SUP> and exhibit the half-integer quantum Hall effect, implying that the quality of graphene grown by chemical vapour deposition is as high as mechanically cleaved graphene. Employing the outstanding mechanical properties of graphene, we also demonstrate the macroscopic use of these highly conducting and transparent electrodes in flexible, stretchable, foldable electronics.

창의적 문제해결력 신장을 위한 초등학교 사회과 수업에서 학습효과에 영향을 미치는 학생변인 분석

이종연 ( Jong Yeon Lee ),구양미 ( Yang Mi Koo ),남민우 ( M. Nam ),박상훈 ( S. Park ),김병수 ( B. Kim ),박도인 ( D. Park ),서정희 ( J. Seo ),고범석 ( B. Go ),진석언 ( Suk Un Jin ) 한국교육정보미디어학회(구 한국교육정보방송학회) 2007 교육정보미디어연구 Vol.13 No.1

본 연구의 목적은 초등학생들의 사전 창의적 문제해결력, 사회과 영역지식, 메타인지, 학습동기, ICT활용능력 수준이 사회과 창의적 문제해결력 신장을 위한 교육 프로그램을 경험한 후 최종적인 창의적 문제해결력 및 사회과 학업성취도에 어떠한 영향을 미치는지 분석하여, 프로그램의 개선 및 효과적인 운영의 시사점을 도출하는 것이다. 연구대상은 서울 마포구 소재 S초등학교 5학년 5개 학급이었다. 5학년 3개 반에는 창의적 문제해결력 증진을 위한 프로그램 온·오프 연계 버전이 적용되었고, 2개 반에는 오프라인 버전이 적용되었다. 학기 시작 전, 본 연구에 참여한 학생들 모두 사전 창의적 문제해결력 검사와 사회과 영역지식 검사를 받았다. 온·오프 연계 그룹 학생들은 메타인지, 학습동기, ICT활용능력 수준을 조사하는 설문지에 응답했고, 오프라인 그룹 학생들은 메타인지, 학습동기 수준을 조사하는 설문지에 응답했다. 조사가 끝난 후, 창의적 문제해결력 증진을 위한 프로그램을 포함한 5학년 2학기 사회과 수업을 진행하였고 모든 수업을 완료한 후, 사후 창의적 문제해결력 검사와 학업성취도 검사를 받았다. 처치그룹별로 단계적 회귀분석을 실시한 결과, 온·오프 연계 버전을 운영하였을 경우, 학습자들의 사전 창의적 문제해결력과 영역지식이 사후 창의적 문제해결력과 학업성취도에 공통적으로 영향력이 있는 것으로 나타났다. 즉 사전 창의적 문제해결력 수준이 높을수록 사회과 기초지식이 많을수록 사후 창의적 문제해결력이 높았고 학업성취도도 높았다. 오프라인 버전을 운영하였을 경우, 학습자들의 영역지식 수준은 사후 창의적 문제해결력과 학업성취도에 공통적으로 영향력을 미치는 것으로 나타났고, 메타인지 수준은 사후 창의적 문제해결력 수준에 영향력이 있는 것으로 나타났다. 본 연구의 결과는 우선 사회과 창의적 문제해결력 증진을 위한 프로그램의 수업효과를 증진시키기 위해서는 버전에 관계없이 학습자의 영역지식 수준을 증진시키는 방안에 주력해야 함을 시사하고 있다. 또한 온·오프 연계 버전 적용 시 학습자의 사전 창의적 문제해결력과 영역지식 수준을 고려하는 운영방안 또는 교과과정 차별화 방안과, 오프라인 버전 적용 시 학습자의 영역지식과 메타인지 수준을 고려하는 운영방안 또는 교과과정 차별화 방안을 마련하는 것이 필요하다는 것을 알 수 있도록 한다. The purpose of this study was to analyze the effects of learners variables such as entry-level creative problem solving skills, domain-knowledge, meta-cognition, motivation, and the level of ICT use on learners` final creative problem solving skills and learning achievement in social studies after running Creative Thinker Program. Creative Thinker Program was composed of 9 units reorganized by Creative Problem Solving Model. A unique online support system was developed to assist teacher`s and students` six step activities in each unit. Five 5th grade classes from an elementary schools located in Seoul were participated in this study and they were divided into two treatment groups, on- & off-line blended treatment group and off-line treatment group. On- & off-line blended treatment meant that the online support system was fully utilized. Off-line treatment meant that most options of the system were substituted by printed materials. Stepwise multiple regression analysis showed that both students` entry-level creative problem solving skills and domain knowledge were significant predictors of final creative problem solving skills and achievement in social studies when running on- & off-line blended version of Creative Thinker Program. In case of off-line version, students` domain knowledge was a significant predictor of their final creative problem solving skills and achievement in social studies. Also students` level of meta-cognition was found to be a significant predictor of their final creative problem solving skills.