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      • Exendin-4 induction of cyclin D1 expression in INS-1 beta-cells: involvement of cAMP-responsive element.

        Kim, M-J,Kang, J-H,Park, Y G,Ryu, G R,Ko, S H,Jeong, I-K,Koh, K-H,Rhie, D-J,Yoon, S H,Hahn, S J,Kim, M-S,Jo, Y-H Journal of Endocrinology, Ltd. [etc.] 2006 The Journal of endocrinology Vol.188 No.3

        <P>Glucagon-like peptide-1 (GLP-1) and its analog exendin-4 (EX) have been considered as a growth factor implicated in pancreatic islet mass increase and beta-cell proliferation. This study aimed to investigate the effect of EX on cyclin D1 expression, a key regulator of the cell cycle, in the pancreatic beta-cell line INS-1. We demonstrated that EX significantly increased cyclin D1 mRNA and subsequently its protein levels. Although EX induced phosphorylation of Raf-1 and extracellular-signal-regulated kinase (ERK), both PD98059 and exogenous ERK1 had no effect on the cyclin D1 induction by EX. Instead, the cAMP-elevating agent forskolin induced cyclin D1 expression remarkably and this response was inhibited by pretreatment with H-89, a protein kinase A (PKA) inhibitor. Promoter analyses revealed that the cAMP-responsive element (CRE) site (at position -48; 5'-TAACGTCA-3') of cyclin D1 gene was required for both basal and EX-induced activation of the cyclin D1 promoter, which was confirmed by site-directed mutagenesis study. For EX to activate the cyclin D1 promoter effectively, CRE-binding protein (CREB) should be phosphorylated and bound to the putative CRE site, according to the results of electrophoretic mobility shift and chromatin immunoprecipitation assays. Lastly, a transfection assay employing constitutively active or dominant-negative CREB expression plasmids clearly demonstrated that CREB was largely involved in both basal and EX-induced cyclin D1 promoter activities. Taken together, EX-induced cyclin D1 expression is largely dependent on the cAMP/PKA signaling pathway, and EX increases the level of phosphorylated CREB and more potently trans-activates cyclin D1 gene through binding of the CREB to the putative CRE site, implicating a potential mechanism underlying beta-cell proliferation by EX.</P>

      • KCI우수등재

        돼지의 선발에 있어서 능력검정 방법에 따른 육종가 및 유전적 개량량의 변화

        조규호,김시동,김명직,이일주,전광주 한국동물자원과학회 2001 한국축산학회지 Vol.43 No.6

        본 연구에서는 이유시체중(㎏), 90㎏ 도달일령을 대상형질로 하여 폐쇄돈군에서 이유시 체중을 기초로 5가지의 선발방법에 따라 선발된 선발축의 산육 능력을 검정하여 검정이 완료된 개체들에 대해 유전능력 평가를 실시한후 검정대상 선발두수의 크기에 따른 유전적 개량량을 비교하여 이상적인 검정방법을 찾고자 실시하였다. 시뮬레이션 결과 90㎏ 도달일령에 대한 육종가 추정치의 변화는 Method Ⅴ그룹에서 -36.2일의 단축효과를 보였으며 세대당 유전적 개량량 또한 Method Ⅴ그룹에서 -7.5일로 가장 높은 개량을 보였다. 따라서 개량적인 측면에 있어서는 전수검정을 실시하는 것이 가장 좋을 것으로 사료되지만 농장의 검정능력이나 전수검정을 실시할 때 드는 초과비용에 대한 경제적인 분석은 더 연구되어져야 될 것으로 사료된다. This study was carried out to find the ideal testing method by comparing predicted breeding values, and genetic gain by the size of testing group. Tested traits were weaning weight and days to 90㎏. Five methods for selecting testing group were adopted: Method Ⅰ (MⅠ ; 30% selected based on litter weight at weaning for female, and 30% selected based on individual weight at weaning for mail), Method Ⅱ (MⅡ ; 30% selected based on individual weight at weaning for female and male, respectively), Method Ⅲ (MⅢ ; 50% selected based on individual weight at weaning for female and male, respectively), Method Ⅳ (MⅣ ; 70% selected based on individual weight at weaning for female and male, respectively), Method Ⅴ (MⅤ ; all piglets were tested). Genetic ability was evaluated by multiple trait animal model using MTDFREML package. Based on the predicted breeding values for days to 90㎏, the next generation was selected up to 5th generation. The above procedure were repeated and simulated by 4 times. The results obtained in the present study are summarized as follows; Phenotypic mean and predicted breeding values mean of days to 90㎏ was 114.3, -27.8, 113.7, -27.0, 107.5, -32.6, 105.7, -34.4, 103.7 and -36.2 days for MⅠ, MⅡ, MⅢ, MⅣ and MⅤ, respectively. Phenotypic and predicted breeding values variance of days to 90㎏ was 20.9, 4.1, 19.0, 3.4, 15.3, 1.8, 13.8, 1.7, 13.3 and 1.2 days for MⅠ, MⅡ, MⅢ, MⅣ and MⅤ, respectively. Genetic gain of days to 90㎏ was -6.2, -6.0, -7.1, -7.3 and -7.5 days for MⅠ, MⅡ, MⅢ, MⅣ and MⅤ, respectively. In all case, Method Ⅴ group, all piglets be tested, is the most efficient for improving the target economic traits.

      • KCI등재

        세관 양광주 방전에서 플라즈마 확산의 완전 해

        김동준,정종문,김정현,황하청,정재윤,조윤희,임현교,구제환,최은하,조광섭,Jin, D.J.,Jeong, J.M.,Kim, J.H.,Hwang, H.C.,Chung, J.Y.,Cho, Y.H.,Lim, H.K.,Koo, J.H.,Choi, E.H.,Cho, G.S. 한국진공학회 2010 Applied Science and Convergence Technology Vol.19 No.1

        관경이 수 mm인 세관 램프 내부에서 플라즈마의 확산을 조사하기 위하여 이극성(ambipolar) 확산방정식을 해하였다. 반경 방향의 확산에 의한 유리관 벽에서의 플라즈마 소멸 특성시간은 $\tau_r\;=\;(r_0/2.4)^2/D_a$로 주어진다. 반경 $r_0{\sim}1\;mm$이고 이극성 확산계수 $D_a{\sim}0.01\;m^2/s$ 이면, $\tau_r{\sim}17\;{\mu}s$이다. 이는 램프의 교류전원 구동에서 플라즈마를 유지하기 위한 구동 최소 주파수 ~30 kHz에 해당한다. 고전압이 인가되는 전극부에 발생한 고밀도의 플라즈마가 양광주로 확산되는 특성시간은 $\tau_z{\sim}0.1\;s$이다. 고밀도 플라즈마 경계에서의 시간에 대한 확산속도는 $t{\sim}10^{-6}\;s$일 때 $u_D{\sim}10^2\;m/s$이고, $t{\sim}10^{-3}\;s$이면 그 속도는 $u_D{\sim}1\;m/s$로 느려진다. 따라서 램프 길이 ~1 m에 대하여 전극부에서 생성된 고밀도 플라즈마가 양광주 전체로 확산되는 시간은 수 초가 걸린다. The ambipolar diffusion equation has been solved in a fine-tube lamp of a few mm in diameter. In the diffusion of radial direction, the plasma diffuses and vanishes away at the glass wall by recombination with the characteristic time of plasma loss is given by $\tau_r\;=\;(r_0/2.4)^2/D_a$. With the radius $r_0{\sim}1\;mm$ and the ambipolar diffusion coefficient $D_a{\sim}0.01\;m^2/s$, the vanishing time is calculated $\tau_r{\sim}10\;{\mu}s$ which corresponds to the least value of frequency 30 kHz for the sustaining the plasma in the operation of high voltage AC-power. In the diffusion of longitudinal z-direction, a high density plasma generated at the area of a high voltage electrode, diffuses into the positive column with the characteristic time $\tau_z{\sim}0.1\;s$. The plasma diffusion velocity at the boundary of high density plasma is $u_D{\sim}10^2\;m/s$ at the time $t{\sim}10^{-6}$ s and the diffusion velocity becomes slow as $u_D{\sim}1\;m/s$ at $t{\sim}10^{-3}\;s$. Therefore, for the long lamp of 1 m, it takes about several seconds for the high density plasma at the area of electrode to diffuse through the whole positive column space.

      • Modeling of forming limit for multilayer sheets based on strain-rate potentials

        Kim, D.,Kim, H.,Kim, J.H.,Lee, M.G.,Kim, K.J.,Barlat, F.,Lee, Y.,Chung, K. Pergamon Press ; Elsevier Science Ltd 2015 International journal of plasticity Vol.75 No.-

        In order to evaluate the forming limits of planar anisotropic multilayer sheet materials, the Marciniak-Kuczynski (M-K) model was formulated based on the strain-rate potential. A common practice to predict the forming limits of sheet materials has been based on yield stress potentials defined in the stress field. As an alternative, a method based on plastic stain-rate potentials, which are especially convenient to apply for rigid-viscoplasticity, was considered in this work. The formulation based on the strain-rate potential facilitates the modeling of forming limits for multilayer sheet materials because the number of unknown variables is significantly reduced by assuming the iso-strain condition for each layer without delamination. As for the strain-rate potential, Srp2003-2d, which is the pseudo-conjugate of the yield stress potential Yld2000-2d, was applied along with Hill's 1948 strain-rate potential for comparison. In the approach proposed, rigid-viscoplasticity was formulated according to the incremental deformation theory based on the minimum plastic work path. The rotation of anisotropic symmetry axes in the groove region was also properly accounted for in the formulation. For verification purposes, the predicted forming limit criteria such as the strain-based forming limit diagram (FLD), the stress-based forming limit diagram (FLSD) and the effective strain-based forming limit diagram (x-EPS) were experimentally validated for a monolithic aluminum alloy (AA5182-O) sheet and a three-layer AA5182-O/polypropylene/AA5182-O (AA/PP/AA) sandwich sheet, which confirmed good agreement. In addition, the path-sensitivity of the strain-based FLD and the path-insensitivity of the FLSD and x-EPS were numerically proven based on the M-K model for the three-layer sandwich sheet. Finally, the M-K model was compared with a maximum force model most recently developed.

      • SCISCIESCOPUS

        Pulse Shape Discrimination of Nuclear Recoil and Electron Recoil Events With a NaI(Tl) Crystal for Dark Matter Search

        Kim, K. W.,Adhikari, G.,Adhikari, P.,Choi, S.,Ha, C.,Hahn, I. S.,Jeon, E. J.,Joo, H. W.,Kang, W. G.,Kim, H. J.,Kim, N. Y.,Kim, S. K.,Kim, Y. D.,Kim, Y. H.,Lee, H. S.,Lee, M. H.,Leonard, D. S.,Oh, S. Y IEEE 2016 IEEE transactions on nuclear science Vol.63 No.2

        <P>In order to investigate discrimination between nuclear recoil and electron recoil events for the KIMS-NaI dark matter search experiment, we measured the pulse shapes produced by neutrons and gamma rays in a NaI(Tl) crystal. Relatively good pulse shape discrimination (PSD) power due to high light output of recently developed crystals makes it possible to test whether the annual modulation signal observed by the DAMA/LIBRA experiment is caused by nuclear recoil events. We applied the PSD to underground data taken with a 9.15 kg low-background and high-light-output NaI(Tl) crystal for 134 days. Good agreement between underground data and electron recoil events was observed.</P>

      • SCIESCOPUSKCI등재

        Characterization of Nutritional Value for Twenty-one Pork Muscles

        Kim, J.H.,Seong, P.N.,Cho, S.H.,Park, B.Y.,Hah, K.H.,Yu, L. H.,Lim, D.G.,Hwang, I.H.,Kim, D.H.,Lee, J.M.,Ahn, C.N. Asian Australasian Association of Animal Productio 2008 Animal Bioscience Vol.21 No.1

        A study was conducted to evaluate nutritional value for twenty-one pork muscles. Ten market-weight crossbred pigs (five gilts and five barrows) were used for evaluating proximate chemical composition, cholesterol, total iron, calorie and fatty acid contents. As preliminary analysis revealed no noticeable sex effect, pooled data from both sexes were used for the final analysis. M. rectus femoris had the highest moisture content, while m. latissimus dorsi was lowest in moisture content (p<0.05). Protein content was highest for m. longissimus dorsi and lowest for m. supraspinatus (p<0.05). The tensor fasciae and latissimus dorsi muscles contained the highest intramuscular fat (p<0.05), while rectus femoris, adductor and vastus lateralis were lowest in intramuscular fat content. When simple correlations between chemical values were computed for the pooled dataset from all muscles, intramuscular fat had significant (p<0.05) negative linear relationships with moisture (r = -0.85) and protein (r = -0.51) contents. Calorie levels were not significantly affected by fat content, while rectus femoris and latissimus dorsi muscles showed lowest and highest calorie contents, respectively (p<0.05). Polyunsaturated fatty acid content was highest (p<0.05) for both m. adductor and m. rectus femoris, while it was lowest for m. longissimus dorsi. Collectively, the current study identified a large amount of variation in nutritional characteristics between pork muscles, and the data can be used for the development of muscle-specific strategies to improve eating quality of meats and meat products.

      • SCISCIESCOPUS

        Extraction of interface states at emitter-base heterojunctions in AlGaAs/GaAs heterostructure bipolar transistors using sub-bandgap photonic excitation

        Kim, S.W.,Roh, K.S.,Seo, S.H.,Kim, K.Y.,Kang, G.C.,Lee, S.,Choi, C.M.,Park, S.R.,Park, J.H.,Chun, K.C.,Song, K.J.,Kim, D.H.,Kim, D.M. Pergamon Press 2008 Microelectronics and reliability Vol.48 No.3

        Distribution of interface states at the emitter-base heterojunctions in heterostructure bipolar transistors (HBTs) is characterized by using current-voltage characteristics using sub-bandgap photonic excitation. Sub-bandgap photonic source with a photon energy E<SUB>ph</SUB> which is less than the energy bandgap E<SUB>g</SUB> (E<SUB>g,GaAs</SUB>=1.42, E<SUB>g,AlGaAs</SUB>=1.76eV) of emitter, base, and collector of HBTs, is employed for exclusive excitation of carriers only from the interface states in the photo-responsive energy range at emitter-base heterointerface. The proposed method is applied to an Al<SUB>0.3</SUB>Ga<SUB>0.7</SUB>As/GaAs HBT (A<SUB>E</SUB>=W<SUB>E</SUB>xL<SUB>E</SUB>=250x100μm<SUP>2</SUP>) with E<SUB>ph</SUB>=0.943eV and P<SUB>opt</SUB>=3mW. Extracted interface trap density D<SUB>it</SUB> was observed to be D<SUB>it,max</SUB>∼4.2x10<SUP>12</SUP>eV<SUP>-1</SUP>cm<SUP>-2</SUP> at emitter-base heterointerface.

      • SCISCIESCOPUS

        Disposition and metabolism of (2S,3S,4R)-N''-cyano-N-(6-amino-3,4-dihydro-3-hydroxy-2-methyl-2-dimethoxy methyl-2H-benzopyran-4-yl)-N'-benzylguanidine, a novel neuroprotective agent for ischemia-reperfusion damage, in rats

        Kim, N. S.,Yoo, H. H.,Lee, M. W.,Kim, H. S.,Kim, D. H. Taylor & Francis 2007 Xenobiotica Vol.37 No.5

        <P> The metabolism and disposition of KR31378 (a benzopyran derivative and a novel neuroprotective agent) were investigated following single oral or intravenous administration of [14C]-KR31378 to rats. [14C]-KR31378 was rapidly absorbed after oral dosing with an oral bioavailability of greater than 71%. The maximum plasma concentration and area under the curve of total radioactivity in rat plasma increased proportionally to the administered dose. KR31378 was distributed over all organs and tissues except for brain, eyeball and testis, and declined by first order kinetics up to 24 h after dosing. Excretion of the radioactivity was 29.5% of the dose in the urine and 58.5% in the feces within 2 days after oral administration. Biliary excretion of the radioactivity in bile duct-cannulated rats was about 66.0% for the first 24 h. KR31378 was extensively metabolized by ring hydroxylation, O-demethylation, oxidation and reduction with subsequent N-acetylation and O-glucuronide conjugation. N-acetylated conjugates (M2, M10, M11, M12, M14, and M15) were identified as the predominant metabolites in rats.</P>

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