Analysis of the relationship between the kinetic energy and intensity of rainfall in Daejeon, Korea

Lim, Y.S.,Kim, J.K.,Kim, J.W.,Park, B.I.,Kim, M.S. Pergamon Press 2015 QUATERNARY INTERNATIONAL Vol.384 No.-

The kinetic energy and momentum of rainfall are widely used as erosivity indicators for estimating soil detachment (erosion) induced by the impact of raindrops. Because direct measurements of the force or kinetic energy of rainfall on ground surfaces are not widely available, many empirical relationships have been derived to link the kinetic energy and intensity (I) of rainfall, the factor that has the most control over soil erosion and is readily accessible. This study considered three rainfall erosivity indices: kinetic energy expenditure (KE<SUB>time</SUB>, J m<SUP>-2</SUP> h<SUP>-1</SUP>), kinetic energy content (KE<SUB>mm</SUB>, J m<SUP>-2</SUP> mm<SUP>-1</SUP>), and momentum (M, kg m s<SUP>-1</SUP> m<SUP>-2</SUP> s<SUP>-1</SUP> or N m<SUP>-2</SUP>). The relationships between these rainfall erosivity indices (KE<SUB>time</SUB>, KE<SUB>mm</SUB>, and M) and rainfall intensity were established by fitting to an existing functional model based on measurements of the number of drops by size and terminal velocity made from January 2010 to July 2011 using a laser optical disdrometer in Daejeon City, Korea. The best fit for the relationship between the three kinetic energy indices and rainfall intensity was obtained with a power law (KE<SUB>time</SUB>-I, and M-I) and an exponential model (KE<SUB>mm</SUB>-I). Validation results for two different events indicated good performance for the KE<SUB>time</SUB>-I and M-I equations, with a similar distribution of observed data and power-law curve fitting. However, the rainfall momentum index produced much lower uncertainty as determined from the measured terminal velocity when the equipment was exposed to in situ changeable conditions. Therefore, we suggest that the power-law relationship between momentum and rainfall intensity is the most suitable equation for the prediction of rainfall erosivity.

Development of the readout system for the K2K SciBar detector

Yoshida, M.,Yamamoto, S.,Murakami, T.,Tanaka, M.,Nakaya, T.,Nishikawa, K.,Joo, K.K.,Kim, B.J.,Kim, J.Y.,Kim, S.B.,Lee, M.J.,Lim, I.T. IEEE 2004 IEEE transactions on nuclear science Vol.51 No.6

Readout electronics for the scintillation bar tracking detector (SciBar) in the K2K neutrino oscillation experiment has been developed. SciBar has 14 336 scintillator bars in total. The deposited energy and timing of particles from neutrino interactions in the scintillator bars are measured by 64-channel multianode photo-multiplier tubes (MAPMTs). Compact custom-designed electronics to record the MAPMT signals were developed, consisting of front-end circuit boards attached to each MAPMT and back-end electronics modules sitting in a VME crate. The front-end circuit board multiplexes pulse-height information from all 64 anodes and generates a fast triggering signal. Two sets of ASICs (IDEAS VA32HDR11 and TA32CG) are employed for these functions. The bias voltages and relay of control signals are also handled on the board. The back-end electronics module controls the front-end board by providing the control, timing, and low-voltage signals. The board also digitizes the multiplexed signal from the front-end. The electronics achieves low noise of less than 0.3 photo-electrons and good linearity up to 300 (150) photo-electrons for MAPMTs at the gain of 5×10<SUP>5</SUP> (10<SUP>6</SUP>).

Novel signaling axis for ROS generation during K-Ras-induced cellular transformation

Park, M-T,Kim, M-J,Suh, Y,Kim, R-K,Kim, H,Lim, E-J,Yoo, K-C,Lee, G-H,Kim, Y-H,Hwang, S-G,Yi, J-M,Lee, S-J Macmillan Publishers Limited 2014 CELL DEATH AND DIFFERENTIATION Vol.21 No.8

Reactive oxygen species (ROS) are well known to be involved in oncogene-mediated cellular transformation. However, the regulatory mechanisms underlying ROS generation in oncogene-transformed cells are unclear. In the present study, we found that oncogenic K-Ras induces ROS generation through activation of NADPH oxidase 1 (NOX1), which is a critical regulator for the K-Ras-induced cellular transformation. NOX1 was activated by K-Ras-dependent translocation of p47<SUP>phox</SUP>, a subunit of NOX1 to plasma membrane. Of note, PKCδ, when it was activated by PDPK1, directly bound to the SH3-N domain of p47<SUP>phox</SUP> and catalyzed the phosphorylation on Ser348 and Ser473 residues of p47<SUP>phox</SUP> C-terminal in a K-Ras-dependent manner, finally leading to its membrane translocation. Notably, oncogenic K-Ras activated all MAPKs (JNK, ERK and p38); however, only p38 was involved in p47<SUP>phox</SUP>-NOX1-dependent ROS generation and consequent transformation. Importantly, K-Ras-induced activation of p38 led to an activation of PDPK1, which then signals through PKCδ, p47<SUP>phox</SUP> and NOX1. In agreement with the mechanism, inhibition of p38, PDPK1, PKCδ, p47<SUP>phox</SUP> or NOX1 effectively blocked K-Ras-induced ROS generation, anchorage-independent colony formation and tumor formation. Taken together, our findings demonstrated that oncogenic K-Ras activates the signaling cascade p38/PDPK1/PKCδ/p47<SUP>phox</SUP>/NOX1 for ROS generation and consequent malignant cellular transformation.

In Vitro/In Vivo Development after Thawing of Vitrified Mouse Blastocysts by Culture Condition and Embryo Transfer Method

김묘경,김은영,이봉경,윤산현,박세필,정길생,임진호,Kim, M.K.,Kim, E.Y.,Yi, B.K.,Yoon, S.H.,Park, S.P.,Chung, K.S.,Lim, J.H. The Korean Society for Reproductive Medicine 1997 Clinical and Experimental Reproductive Medicine Vol.24 No.3

본 실험은 초자화 동결된 생쥐 배반포기배의 융해 후 배양조건 및 이식방법이 난자의 생존에 미치는 효과를 조사하고자 실시하였다. 체외수정후, M16배양액에서 4일동안 배양하여 얻어진 생쥐 배반포기배는 EFS40 (40% ethylene glycol, 18% Ficoll, 0.5 M sucrose가 함유된 PBS)으로 초자화동결하였다. 실험 I에서는 융해 후 배양조건에 따른 난자들의 체외/체내 생존율을 조사하였다. 융해된 난자가 M16과 4 mg/ml 소혈청알부민과 20 가지 아미노산이 함유된 m-CR1 (2% BME 아미노산 용액, 1% MEM 아미노산 용액) 및 단층배양이 유도된 난구세포 (10% FBS가 함유된 m-CR1배양액)에서 각각 배양되었을 때, 융해 후 24시간째 체외 생존율은 배양조건에 따라 차이가 없었다(75.6, 83.1, 82.4%). 그러나 체내 발달율에 있어서 임신 15일째 생존 산자율은 39.0, 49.0, 38.1%로서 유사한 성적을 나타냈으나, 전체 착상율에 있어서는 m-CR1 (80.4%)에 배양되었을 때, M16 (51.2%), 난구세포와 공배양시 (57.1%)보다 유의하게 높은 생존율을 보였다(p<0.05). 실험 II에서는 수정란 이식 방법에 따른 체내 발달율을 조사하였다. 배반포기배를 융해 후 체외배양없이 곧바로 가임신 2, 3일째 대리모에 이식을 실시하였을 때, 가임신 2일째 대리모에서는 임신징후를 얻지 못하였고, 가임신 3일째 대리모에서는 50.0%의 착상율과 15.4%의 정상산자율을 얻었다. 그러나, 이러한 결과는 융해 후, 16시간 배양하여 가임신 3일째 대리모에 이식 (73.5, 57.1%)하는 경우보다 유의하게 낮은 결과였다(p<0.05). 실험 III에서는 초자화 동결된 배반포기배의 융해 후 배양시 발달이 늦어진 수정란의 이용효율을 극대화시키기 위해 융해한 4일째 초기, 5일째 초기, 5일째 팽창 배반포기배의 체외/체내 생존율을 조사하였다. 가장 높은 체외 생존율은 5일째 팽창 배반포기배 (78.3%)에서 얻었으나, 체내 발달율 (산자율, 착상율)에 있어서는 4일째 초기 배반포기배 (33.3, 66.7%)의 경우가, 5일째 팽창 배반포기배(29.0, 38.7%)의 경우보다 높았다(p<0.05). 따라서 본 연구의 결과는 배양조건과 수정란 이식방법에 따라 초자화 동결된 배아의 체외/체내 발달율을 높일 수 있으며, 발달이 늦은 배반포기배의 체내 발달율은 체외 배양시간이 길어질수록 낮아짐으로, 5일째 팽창 배반포기배보다 4일째 초기 배반포기배를 동결하는 것이 더 유용하다는 것을 알 수 있었다. This study was to test whether in vitro/in vivo survival of vitrified mouse blastocysts was influenced by culture conditions and ET method. Mouse blastocysts were obtained from in vitro fertilization and cultured for 4 days in M16 medium, and they were vitrified in EFS40 which contained 40% ethlyene glycol, 18% Ficoll and 0.5 mol sucrose in PBS. In experiment I, in vitro and in vivo survival rate of these embryos were evaluated in different culture condition after thawing. When thawed embryos were cultured in M16 medium as a control, m-CR1 medium contained 20 amino acids (2% BME amino acis and 1% MEM non-essential amino acids solution) and 4 mg/ml BSA and cumulus monolayer cell co-cultured condition in mCR1 medium (10% FBS), their in vitro survival at 24 hr after thawing was not affected by culture condition (75.6, 83.1, 82.4%). However, in vivo survival rates of implantation in m-CR1 medium (80.4%) were significantly higher than those of M16 medium (51.2%), co-culture (57.1%) condition, although there was no difference in live fetuses rates on day 15 gestation (39.0, 49.0, 38.1%). In experiment II, the in vivo development potential of embryos by ET methods was examined. When blastocysts were transferred to the day 2, 3 pseudopregnant recipient without culture soon after thawing, no pregnant recipient was obtained on the day 2 pseudopregnancy, and 50% of pregnancy rates and 15.4% of live fetus rates were obtained on the day 3 pseudopregnant recipients. These results were significantly lower than those of transferred group (day 3 pseudopregnant recipients) after culture for 16 hr post thawing (73.5, 57.1%) (p<0.05). In experiment III, to elevate usability of delayed embryos in vitro/in vivo survival of vitrified embryos (day 4 early, day 5 early and expanding blastocyst) were examined. in vivo survival rates (live fetus, total implantation) were higher in day 4 early blastocysts (33.3, 66.7%) than in day 5 expanding blastocysts (29.0, 38.7%), although the highest in vitro survival rates were obtained in the day 5 expanding brastocysts (78.3%). Therefore, these results suggest that the in vitro/in vivo survival rates of vitrified embryos could be improve by the culture condition and ET method and that the in vivo development rates of delayed embryos were decreased with longer culture duration in vitro. It means that more effective cryopreservation was obtained in day 4 early blastocysts than in day 5 expanding blastocysts.

Effects of catalpalactone on dopamine biosynthesis and L-DOPA-induced cytotoxicity in PC12 cells

Huang, H.S.,Han, X.H.,Hwang, B.Y.,Park, J.I.,Yoo, S.K.,Lee, H.J.,Lim, S.C.,Lee, M.K. Elsevier Science B.V 2008 Environmental toxicology and pharmacology Vol.26 No.1

The effects of catalpalactone on dopamine biosynthesis and L-DOPA-induced cytotoxicity in PC12 cells were investigated. Catalpalactone at 5-30μM decreased intracellular dopamine content with the IC<SUB>50</SUB> value of 22.1μM. Catalpalactone at 5-20μM, but not 30μM, did not alter cell viability. Catalpalactone at 20μM inhibited tyrosine hydroxylase (TH) and aromatic-l-amino acid decarboxylase (AADC) activities. Catalpalactone also decreased cyclic AMP levels and inhibited TH phosphorylation. In addition, catalpalactone at 20μM reduced the increases in dopamine levels induced by L-DOPA (20-50μM). Catalpalactone (5-30μM) associated with L-DOPA (50-100μM) enhanced L-DOPA-induced cytotoxicity at 48h, which was prevented by N-acetyl-l-cysteine. These results suggest that catalpalactone inhibited dopamine biosynthesis by reducing TH and AADC activities and enhanced L-DOPA-induced cytotoxiciy in PC12 cells.

Properties of MTiO₃ (M = Sr, Ba) and PbM'O₃(M'= Ti, Zr) Superlattice Thin Films Fabricated by Laser Ablation

Lim, T.M.,Park, J.Y.,Han, J.S.,Hwang, P.G.,Lee, K.H.,Jung, K.W.,Jung, D. Korean Chemical Society 2009 Bulletin of the Korean Chemical Society Vol.30 No.1

$BaTiO_3/SrTiO_3$ and $PbTiO_3/PbZrO_3$ superlattice thin films were fabricated on $Pt/Ti/SiO_2/Si$ substrate by the pulsed laser deposition process. The morphologies and physical properties of deposited films were characterized by using X-ray diffractometer, HR-SEM, and Impedance Analyzer. XRD data and SEM images of the films indicate that each layer was well deposited alternatively in the superlattice structure. The dielectric constant of $BaTiO_3/SrTiO_3$ superlattice thin film was higher than that of individual $BaTiO_3$ or $SrTiO_3$ film. Same result was obtained in the $PbTiO_3/PbZrO_3$system. The dielectric constant of a superlattice film was getting higher as the number of layer is increased.

Ionic and carbonaceous compositions of PM10, PM2.5 and PM1.0 at Gosan ABC Superstation and their ratios as source signature

Lim, S.,Lee, M.,Lee, G.,Kim, S.,Yoon, S.,Kang, K. Copernicus GmbH 2012 Atmospheric Chemistry and Physics Vol.12 No.4

<P>Abstract. PM1.0, PM2.5, and PM10 were sampled at Gosan ABC Superstation on Jeju Island from August 2007 to September 2008. The carbonaceous aerosols were quantified with the thermal/optical reflectance (TOR) method, which produced five organic carbon (OC) fractions, OC1, OC2, OC3, OC4, and pyrolyzed organic carbon (OP), and three elemental carbon (EC) fractions, EC1, EC2, and EC3. The mean mass concentrations of PM1.0, PM2.5, and PM10 were 13.7 μg m−3, 17.2 μg m−3, and 28.4 μg m−3, respectively. The averaged mass fractions of OC and EC were 23.0% and 10.4% for PM1.0, 22.9% and 9.8% for PM2.5, and 16.4% and 6.0% for PM10. Among the OC and EC sub-components, OC2 and EC2+3 were enriched in the fine mode, but OC3 and OC4 in the coarse mode. The filter-based PM1.0 EC agreed well with black carbon (BC) measured by an Aethalometer, and PM10 EC was higher than BC, implying less light absorption by larger particles. EC was well correlated with sulfate, resulting in good relationships of sulfate with both aerosol scattering coefficient measured by Nephelometer and BC concentration. Our measurements of EC confirmed the definition of EC1 as char-EC emitted from smoldering combustion and EC2+3 as soot-EC generated from higher-temperature combustion such as motor vehicle exhaust and coal combustion (Han et al., 2010). In particular, EC1 was strongly correlated with potassium, a traditional biomass burning indicator, except during the summer, when the ratio of EC1 to EC2+3 was the lowest. We also found the ratios of major chemical species to be a useful tool to constrain the main sources of aerosols, by which the five air masses were well distinguished: Siberia, Beijing, Shanghai, Yellow Sea, and East Sea types. Except Siberian air, the continental background of the study region, Beijing plumes showed the highest EC1 (and OP) to sulfate ratio, which implies that this air mass had the highest net warming by aerosols of the four air masses. Shanghai-type air, which was heavily influenced by southern China, showed the highest sulfate enhancement. The highest EC2+3/EC1 ratio was found in aged East Sea air, demonstrating a significant influence of motor vehicle emissions from South Korea and Japan and less influence from industrial regions of China. The high ratio results from the longer residence time and less sensitivity to wet scavenging of EC2+3 compared to EC1, indicating that soot-EC could have greater consequence in regional-scale warming. </P>

Machining of the KSTAR TF coil structure

K. H. Hong,C. H. Choi,D. H. Park,D. K. Hur,H. Sin,H. K. Park,H. T. Kim,J. H. Won,J. H. Lim,J. M. Chung,박주식,J. W. Sa,J. Y. Song,N. G. Kim,S. H. Hwang,Y. D. Chu,Y. G. Song 한국물리학회 2006 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.49 No.III

The KSTAR Toroidal Field (TF) magnet system consists of 16 TF structures. Each structure must be machined for precise assembly and reducing error field. Dimensions of the structure are a height of 4.5 m and a width of 3.2 m. The allowable tolerance of the structure is ±1 2 mm, and that of the bolt hole for Poloidal Field (PF) coil basement is ±0.5 mm. The final machining of the structure is also important for assembly of the interface structures such as toroidal ring, PF coil structures, and Central Solenoid (CS) structure. Before coil encasing, the inside surface of the structure is machined. Most of the outer surface of the structure, except for the surface of the intercoil structure (ICS), is machined after final welding. In particular, the side surface of an inboard leg, the connection plate of the ICS, the toroidal ring basement, the PF structure basements, shear key holes, and conical bolt holes are precisely machined. Fabrication and assembly tolerances are absorbed by the thickness of the electrical insulation, the spacer of the shear key, and the taper ring of the conical bolt. Six TF coil structures have been assembled and two structures are waiting for assembly. Another three structures are under final machining. A laser tracker is used for three dimensional survey and measurement of the structure.

Nuclear magnetic resonance study of the ferroelastic phase transition of order-disorder type in [N(C₂H₅)₄]₂CdCl₄

Lim, A.R.,Kim, M.S.,Lim, K.Y. Elsevier 2016 Solid state sciences Vol.58 No.-

<P>This study uses nuclear magnetic resonance (NMR) techniques to examine the detailed changes in [N(C2H5)(4)](2)CdCl4 around its phase transition at the temperature T-C = 284 K. The chemical shifts and spin-lattice relaxation times in the rotating frame (T-1 rho) were determined from H-1 magic angle spinning (MAS) NMR and C-13 cross-polarization (CP)/ MAS NMR spectra. The two sets of inequivalent H-1 and C-13 nuclei in CH3 and CH2 were distinguished. A ferroelastic phase transition was observed at T-C, without structural symmetry change. The phase transition is mainly attributed to the orientational ordering of the [N(C2H5)(4)](+) cations, and the spectral splitting at low temperature is associated with different ferroelastic domains. (C) 2016 Elsevier Masson SAS. All rights reserved.</P>

An emerging recombinant cluster of nephropathogenic strains of avian infectious bronchitis virus in Korea

Lim, T.H.,Lee, H.J.,Lee, D.H.,Lee, Y.N.,Park, J.K.,Youn, H.N.,Kim, M.S.,Lee, J.B.,Park, S.Y.,Choi, I.S.,Song, C.S. Elsevier Science 2011 Infection, genetics and evolution Vol.11 No.3

The infectious bronchitis virus (IBV) is continuously evolving through point mutation and recombination of their genome, subsequently the emergence of IBV variants complicates disease control. The objective of this study was to investigate genetic characterization of new IBV variants isolated from commercial chicken flocks in Korea collected between 2005 and 2010. Phylogenetic analysis revealed that all new IBV isolates belonged to Korean group II (K-II), which included the nephropathogenic IBV strains. However, the isolates formed a new gene cluster that was distinguished from the two distinct K-II subgroups (KM91-like and QX-like). Recombination events were identified in the S1 gene, with their putative parental strains being the KM91-like or QX-like subgroup. In addition, two crossover sites were observed in the S1 gene of IBV isolates. These results suggest that natural genetic recombination between heterologous strains classified into different genetic groups has occurred and may have caused the emergence of new IBV strains. This finding provides important information on IBV evolution and is essential for the effective control of IB in Korea.