S. Typhi, S. Typhimurium 및 S. Enteritidis 균의 분자역학적 연구

강연호,박미선,김성한,유재연,김호훈,이복권 국립보건연구원 1998 국립보건원보 Vol.35 No.-

Neural stem cells injured by oxidative stress can be rejuvenated by GV1001, a novel peptide, through scavenging free radicals and enhancing survival signals

Park, H.H.,Yu, H.J.,Kim, S.,Kim, G.,Choi, N.Y.,Lee, E.H.,Lee, Y.J.,Yoon, M.Y.,Lee, K.Y.,Koh, S.H. Elsevier BV 2016 NeuroToxicology Vol.55 No.-

<P>Oxidative stress is a well-known pathogenic mechanism of a diverse array of neurological diseases, and thus, numerous studies have attempted to identify antioxidants that prevent neuronal cell death. GV1001 is a 16-amino-acid peptide derived from human telomerase reverse transcriptase (hTERT). Considering that hTERT has a strong antioxidant effect, whether GV1001 also has an antioxidant effect is a question of interest. In the present study, we aimed to investigate the effects of GV1001 against oxidative stress in neural stem cells (NSCs). Primary culture NSCs were treated with different concentrations of GV1001 and/or hydrogen peroxide (H2O2) for various time durations. The H2O2 decreased the viability of the NSCs in a concentration-dependent manner, with 200 mu M H2O2 significantly decreasing both proliferation and migration. However, treatment with GV1001 rescued the viability, proliferation and migration of H2O2 injured NSCs. Consistently, free radical levels were increased in rat NSCs treated with H2O2, while co-treatment with GV1001 significantly reduced these levels, especially the intracellular levels. In addition, GV1001 restored the expression of survival-related proteins and reduced the expression of death associated ones in NSCs treated with H2O2. In conclusion, GV1001 has antioxidant and neuroprotective effects in NSCs following treatment with H2O2, which appear to be mediated by scavenging free radicals, increasing survival signals and decreasing death signals. (C) 2016 Elsevier B.V. All rights reserved.</P>

Complete chloroplast genome sequences of Solanum commersonii and its application to chloroplast genotype in somatic hybrids with Solanum tuberosum

Cho, K. S.,Cheon, K. S.,Hong, S. Y.,Cho, J. H.,Im, J. S.,Mekapogu, M.,Yu, Y. S.,Park, T. H. Springer International 2016 Plant cell reports Vol. No.

<P>Chloroplast genome of Solanum commersonii and S olanum tuberosum were completely sequenced, and Indel markers were successfully applied to distinguish chlorotypes demonstrating the chloroplast genome was randomly distributed during protoplast fusion. Somatic hybridization has been widely employed for the introgression of resistance to several diseases from wild Solanum species to overcome sexual barriers in potato breeding. Solanum commersonii is a major resource used as a parent line in somatic hybridization to improve bacterial wilt resistance in interspecies transfer to cultivated potato (S. tuberosum). Here, we sequenced the complete chloroplast genomes of Lz3.2 (S. commersonii) and S. tuberosum (PT56), which were used to develop fusion products, then compared them with those of five members of the Solanaceae family, S. tuberosum, Capsicum annum, S. lycopersicum, S. bulbocastanum and S. nigrum and Coffea arabica as an out-group. We then developed Indel markers for application in chloroplast genotyping. The complete chloroplast genome of Lz3.2 is composed of 155,525 bp, which is larger than the PT56 genome with 155,296 bp. Gene content, order and orientation of the S. commersonii chloroplast genome were highly conserved with those of other Solanaceae species, and the phylogenetic tree revealed that S. commersonii is located within the same node of S. tuberosum. However, sequence alignment revealed nine Indels between S. commersonii and S. tuberosum in their chloroplast genomes, allowing two Indel markers to be developed. The markers could distinguish the two species and were successfully applied to chloroplast genotyping (chlorotype) in somatic hybrids and their progenies. The results obtained in this study confirmed the random distribution of the chloroplast genome during protoplast fusion and its maternal inheritance and can be applied to select proper plastid genotypes in potato breeding program.</P>

Peroxiredoxin II promotes hepatic tumorigenesis through cooperation with Ras/Forkhead box M1 signaling pathway

Park, Y-H,Kim, S-U,Kwon, T-H,Kim, J-M,Song, I-S,Shin, H-J,Lee, B-K,Bang, D-H,Lee, S-J,Lee, D-S,Chang, K-T,Kim, B-Y,Yu, D-Y Macmillan Publishers Limited 2016 Oncogene Vol.35 No.27

<P>The current study was carried out to define the involvement of Peroxiredoxin (Prx) II in progression of hepatocellular carcinoma (HCC) and the underlying molecular mechanism(s). Expression and function of Prx II in HCC was determined using H-ras(G12V)-transformed HCC cells (H-ras(G12V)-HCC cells) and the tumor livers from H-ras(G12V)-transgenic (Tg) mice and HCC patients. Prx II was upregulated in H-ras(G12V)-HCC cells and H-ras(G12V)-Tg mouse tumor livers, the expression pattern of which highly similar to that of forkhead Box M1 (FoxM1). Moreover, either knockdown of FoxM1 or site-directed mutagenesis of FoxM1-binding site of Prx II promoter significantly reduced Prx II levels in H-ras(G12V)-HCC cells, indicating FoxM1 as a direct transcription factor of Prx II in HCC. Interestingly, the null mutation of Prx II markedly decreased the number and size of tumors in H-ras(G12V)-Tg livers. Consistent with this, knockdown of Prx II in H-ras(G12V)-HCC cells reduced the expression of cyclin D1, cell proliferation, anchorage-independent growth and tumor formation in athymic nude mice, whereas overexpression of Prx II increased or aggravated the tumor phenotypes. Importantly, the expression of Prx II was correlated with that of FoxM1 in HCC patients. The activation of extracellular signal-related kinase (ERK) pathway and the expression of FoxM1 and cyclin D1 were highly dependent on Prx II in H-ras(G12V)-HCC cells and H-ras(G12V)-Tg livers. Prx II is FoxM1-dependently- expressed antioxidant in HCC and function as an enhancer of Ras(G12V) oncogenic potential in hepatic tumorigenesis through activation of ERK/FoxM1/cyclin D1 cascade.</P>

Comparison of 90‐day case‐fatality after ischemic stroke between two different stroke outcome registries using propensity score matching analysis

Yu, K‐,H.,Hong, K‐,S.,Lee, B‐,C.,Oh, M‐,S.,Cho, Y‐,J.,Koo, J‐,S.,Park, J‐,M.,Bae, H‐,J.,Han, M‐,K.,Ju, Y‐,S.,Kang, D‐,W.,Appelros, P. Blackwell Publishing Ltd 2011 Acta neurologica Scandinavica Vol.123 No.5

<P>Yu K‐H, Hong K‐S, Lee B‐C, Oh M‐S, Cho Y‐J, Koo J‐S, Park J‐M, Bae H‐J, Han M‐K, Ju Y‐S, Kang D‐W, Appelros P, Norrving B, Terent A. Comparison of 90‐day case‐fatality after ischemic stroke between two different stroke outcome registries using propensity score matching analysis. 
Acta Neurol Scand: 2011: 123: 325–331. 
© 2010 John Wiley & Sons A/S.</P><P><B>Background – </B> It has not been clarified whether the disparity in ischemic stroke outcome between populations is caused by ethnic and geographic differences or by variations in case mix. Propensity score matching (PSM) analysis can overcome some analytical problems but is rarely used in stroke outcome research. This study was to compare the ischemic stroke case‐fatality between two PSM cohorts of Sweden and Korea.</P><P><B>Methods – </B> Prognostic variables related to baseline characteristics and stroke care were included in our PSM model. Then, we selected 7675 Swedish and 1220 Korean patients with ischemic stroke from each stroke registers and performed one‐to‐one matching based on propensity scores of each patient.</P><P><B>Results – </B> After PSM, all measured variables were well balanced in 1163 matched subjects, and the 90‐day case‐fatality was identical 6.2% (HR 0.997, 95%CI 0.905–1.099) in Sweden and Korea.</P><P><B>Conclusions – </B> No difference is found in the 90‐day case‐fatality in propensity score‐matched Swedish and Korean patients with ischemic stroke.</P>

Fatigue performance of deepwater SCR under short-term VIV considering various S-N curves

Kim, D.K.,Choi, H.S.,Shin, C.S.,Liew, M.S.,Yu, S.Y.,Park, K.S. Techno-Press 2015 Structural Engineering and Mechanics, An Int'l Jou Vol.53 No.5

In this study, a method for fatigue performance estimation of deepwater steel catenary riser (SCR) under short-term vortex-induced vibration was investigated for selected S-N curves. General tendency between S-N curve capacity and fatigue performance was analysed. SCRs are generally used to transport produced oil and gas or to export separated oil and gas, and are exposed to various environmental loads in terms of current, wave, wind and others. Current is closely related with VIV and it affects fatigue life of riser structures significantly. In this regards, the process of appropriate S-N curve selection was performed in the initial design stage based on the scale of fabrication-related initial imperfections such as welding, hot spot, crack, stress concentration factor, and others. To draw the general tendency, the effects of stress concentration factor (SCF), S-N curve type, current profile, and three different sizes of SCRs were considered, and the relationship between S-N curve capacity and short-term VIV fatigue performance of SCR was derived. In case of S-N curve selection, DNV (2012) guideline was adopted and four different current profiles of the Gulf of Mexico (normal condition and Hurricane condition) and Brazil (Amazon basin and Campos basin) were considered. The obtained results will be useful to select the S-N curve for deepwater SCRs and also to understand the relationship between S-N curve capacity and short-term VIV fatigue performance of deepwater SCRs.

Electrochemical properties of Si/(FeSiB) anode materials prepared by high-energy mechanical milling

Yu, H.T.,Loka, C.,Lee, K.S.,Cho, J.S.,Lee, S.H. Elsevier 2013 Materials science & engineering. B, Advanced funct Vol.178 No.20

Nano-structured composite with overall atomic composition Si<SUB>60</SUB>/(FeSiB)<SUB>40</SUB> has been synthesized by high-energy mechanical milling (HEMM) for Lithium-ion rechargeable batteries as anode material. Crystal structure, microstructure, electrochemical properties, elastic modulus and Vickers hardness (H<SUB>V</SUB>) have been observed by X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HR-TEM), electrochemical test and nano-indentation test. With increasing milling time from 6 to 10h, we observed a relatively homogeneous structure comprised of nano-crystalline active silicon (Si) embedded in less active FeSiB matrix phase. Electrochemical properties of 10h milled nano-composite powder offers low capacity fade, high coulombic efficiency from 3rd cycle (540mAhg<SUP>-1</SUP>) to until 102nd cycle (495mAhg<SUP>-1</SUP>). The coulombic efficiencies of both 6 and 10h milled powders are 98% and 99%, respectively. Coin cell cross sections of 6 and 10h milled powders showed evidence for the void formation during lithiation and delithiation. Nano-indentation results exhibited that the amorphous FeSiB flakes have 2.96 times higher recoverable energy than Si. Resultant composite powders showed high irreversible capacity and stable lithiation and delithiation due to the reduced particle size, increased surface area and the highly elastic FeSiB matrix phase. Research reveals that the obtained nano-composite can be a promising candidate for lithium-ion rechargeable batteries.

S-BRT 운행행태를 고려한 저상버스의 정차시간 예측모형

신소명,이수범,김영찬,박신형,유연승,최정훈,Shin, S.M.,Lee, S.B.,Kim, Y.C.,Park, S.H.,Yu, Y.S.,Choi, J.H. 한국안전학회 2021 한국안전학회지 Vol.36 No.1

This basic study introduces the concept of S-BRT and develops dwell time estimation models that consider road geometry and S-BRT characteristics for a signal operation strategy to meet the S-BRT's operational goal of high speed and punctuality. Field surveys of low-floor buses similar in shape to S-BRTs and data collection of passengers, station elements, vehicle elements, and other factors that can affect stop times were used in a regression analysis to establish statistically significant dwell time estimation models. These dwell time estimation models are developed by categorizing according to the locations of the signal or sidewalk that have the most impact on the dwell time. In this way, the number of people boarding and alighting the bus at the crowded door and the number of people boarding and alighting the bus at the front door considering the internal congestion was analyzed to affect the dwell time. The estimation dwell time models in this study can be used in the establishment of strategies that provide priority signals to S-BRTs.

Effects of O3 and H2O as oxygen sources on the atomic layer deposition of HfO2 gate dielectrics at different deposition temperatures

Lee, S.,Kim, H.,Lee, J.,Yu, I. H.,Lee, J. H.,Hwang, C. Royal Society of Chemistry 2014 Journal of Materials Chemistry C Vol.2 No.14

Variations in the growth behavior, physical and electrical properties, and microstructure of the atomic layer deposited (ALD) HfO2 gate dielectrics were examined with two types of oxygen sources: O-3 and H2O for the given Hf-precursor of Hf[N(CH3)(C2H5)](4). The ALD temperature windows for O-3 and H2O were 240-320 degrees C and 200-280 degrees C, respectively, with the growth rate of HfO2 using O-3 being higher than that of the films using H2O within the ALD window. While the film density of HfO2 using O-3 decreased, the film density of HfO2 using H2O increased with the decreasing ALD temperature. As the deposition temperature decreased, the amount of impurity in the HfO2 film with the O-3 oxidant increased due to the insufficient reaction, which led to the crystallization of the HfO2 film into the tetragonal structure after the post-deposition annealing at 600 degrees C. The films with a lower density and a higher carbon-impurity concentration retained the portion of the tetragonal phase (similar to 30%) to the highest annealing temperature of 1000 degrees C. However, the HfO2 films grown at 200 degrees C with H2O showed the best electrical performance, which could be ascribed to the highest density, low impurity concentration, and negligible involvement of the interfacial low dielectric layer.

Methane to acetylene conversion by employing cost-effective low-temperature arc

Kang, H.s.,Lee, D.h.,Kim, K.t.,Jo, S.,Pyun, S.,Song, Y.h.,Yu, S. Elsevier Scientific Pub. Co 2016 Fuel processing technology Vol.148 No.-

A plasma process for methane conversion into acetylene is proposed. Acetylene is one of the basic materials used in the chemical industry and its production is predominantly based on chemical processing of naphtha and CaC<SUB>2</SUB>. The recent increase in shale gas production makes acetylene production from methane a feasible expectation. This study provides data on the lowest cost of acetylene production from methane by a plasma process. The proposed plasma process is based on an effective rotating arc reactor. The rotating arc provides a relatively low reaction temperature, achieving a high carbon balance. Through a study of reaction parameters and the effect of H<SUB>2</SUB> as a reactant additive, the mechanism of methane conversion was analyzed. The proposed process showed a high efficiency with a minimum process cost of approximately 9kWh/kg-C<SUB>2</SUB>H<SUB>2</SUB>.