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.

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.

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.

200 GeV/핵자 유황이온과 핵건판핵의 충돌에 의해 생성된 헬륨 파쇄핵의 극한파쇄 연구

김동철,송진섭,윤천실,정성헌,박인곤,김종오,김철수,김태연,이승희,조재희,천병구,김재률,김준원,김태익,박명렬,장한일,임인택 慶尙大學校 기초과학연구소 1992 基礎科學硏究所報 Vol.8 No.-

고에너지 중이온 원자핵과 핵건판의 충돌에서, 200GeV/핵자 유황이온에 의해 생성된 파쇄 헬륨핵(Z=2)의 실험실계의 방출각 분포는 표적핵에 무관한 회귀공식. dN=exp[a+k exp(η-y_b)]d[exp(η-y_b)]로 잘 표현된다. 여기에서 의사신속도 η=-ln[tan(θ/2)]이고, y_b는 실험실계의 입사입자(^32S)의 신속도이다. 이 공식에 의한 적합에서 k=-0.057±0.008로 얻어진다. 즉, 핵건판과 고에너지 중이온의 충돌에서 파쇄 헬륨핵의 exp(η-y_b)의 분포는 "극한파쇄" 현상을 잘 설명하고 있다. The angular distribution of emission angle θ of helium (Z=2) produced in the collisions of incident particles of 200 GeV/nucleon ^32S in nuclear emulsion is well expressed by dN=exp[a+k exp(η-y_b)]d[exp(η-y_b)] where the pseudorapidity is η=-ln[tan(θ/2)], the laboratory system primary rapidity is y_b, and k=-0.057+0.008. The shape of this frequency of occurrence distributions in terms of exp(η-y_b) attests to the validity of the concept of "limiting fragmentation" for helium projectile fragments produced in the projectile fragmentation regions of heavy ion collisions in nuclear emulsion.

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.

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.

Effect of dietary soy intake on breast cancer risk according to menopause and hormone receptor status

Kim, YA Cho;Park, K-S;Lim, S-Y;Shin, A;Sung, M-K;Ro, J Sookmyung Women's University Research Institute of 2011 여성과 건강 Vol.6 No.2

Background: Although high soy consumption may be associated with lower breast cancer risk in Asian populations, findings from epidemiological studies have been inconsistent. Objective: We investigated the effects of soy intake on breast cancer risk among Korean women according to their menopausal and hormone receptor status. Methods: We conducted a case-control study with 358 incident breast cancer patients and 360 age-matched controls with no history of malignant neoplasm. Dietary consumption of soy products was examined using a 103-item food frequency questionnaire. Results: The estimated mean intakes of total soy and isoflavones from this study population were 76.5 g per day and 15.0 mg per day, respectively. Using a multivariate logistic regression model, we found a significant inverse association between soy intake and breast cancer risk, with a dose-response relationship (odds ratios (OR) (95% confidence interval (Cl)) for the highest vs the lowest intake quartile: 0.36 (0.20-0.64)). When the data were stratified by menopausal status, the protective effect was observed only among postmenopausal women (OR (95% Cl) for the highest vs the lowest intake quartile: 0.08 (0.03-0.22)). The association between soy and breast cancer risk did not differ according to estrogen receptor (ER)/progesterone receptor (PR) status, but the estimated intake of soy isoflavones showed an inverse association only among postmenopausal women with ER + /PR+ tumors. Conclusions: Our findings suggest that high consumption of soy might be related to lower risk of breast cancer and that the effect of soy intake could vary depending on several factors.

Expression of Antisense Polygalacturonase Gene in Transgenic Tomato

Kim, Y. M 한국식물조직배양학회 1995 식물생명공학회지 Vol.22 No.6

The LIM-only transcription factor LMO2 determines tumorigenic and angiogenic traits in glioma stem cells

Kim, S-H,Kim, E-J,Hitomi, M,Oh, S-Y,Jin, X,Jeon, H-M,Beck, S,Jin, X,Kim, J-K,Park, C G,Chang, S-Y,Yin, J,Kim, T,Jeon, Y-j,Song, J,Lim, Y C,Lathia, J D,Nakano, I,Kim, H Macmillan Publishers Limited 2015 CELL DEATH AND DIFFERENTIATION Vol.22 No.9

Glioblastomas (GBMs) maintain their cellular heterogeneity with glioma stem cells (GSCs) producing a variety of tumor cell types. Here we interrogated the oncogenic roles of Lim domain only 2 (LMO2) in GBM and GSCs in mice and human. High expression of LMO2 was found in human patient-derived GSCs compared with the differentiated progeny cells. LMO2 is required for GSC proliferation both in vitro and in vivo, as shRNA-mediated LMO2 silencing attenuated tumor growth derived from human GSCs. Further, LMO2 is sufficient to induce stem cell characteristics (stemness) in mouse premalignant astrocytes, as forced LMO2 expression facilitated in vitro and in vivo growth of astrocytes derived from Ink4a/Arf null mice and acquisition of GSC phenotypes. A subset of mouse and human GSCs converted into vascular endothelial-like tumor cells both in vitro and in vivo, which phenotype was attenuated by LMO2 silencing and promoted by LMO2 overexpression. Mechanistically, the action of LMO2 for induction of glioma stemness is mediated by transcriptional regulation of Jagged1 resulting in activation of the Notch pathway, whereas LMO2 directly occupies the promoter regions of the VE-cadherin gene for a gain of endothelial cellular phenotype. Subsequently, selective ablation of human GSC-derived VE-cadherin-expressing cells attenuated vascular formation in mouse intracranial tumors, thereby significantly prolonging mouse survival. Clinically, LMO2 expression was elevated in GBM tissues and inversely correlated with prognosis of GBM patients. Taken together, our findings describe novel dual roles of LMO2 to induce tumorigenesis and angiogenesis, and provide potential therapeutic targets in GBMs.

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

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

BaTiO3/SrTiO3 and PbTiO3/PbZrO3 superlattice thin films were fabricated on Pt/Ti/SiO2/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 BaTiO3/SrTiO3 superlattice thin film was higher than that of individual BaTiO3 or SrTiO3 film. Same result was obtained in the PbTiO3/PbZrO3 system. The dielectric constant of a superlattice film was getting higher as the number of layer is increased.