Sphingosine-1-phosphate-induced Flk-1 transactivation stimulates mouse embryonic stem cell proliferation through S1P₁/S1P₃-dependent β-arrestin/c-Src pathways

Ryu, J.M.,Baek, Y.B.,Shin, M.S.,Park, J.H.,Park, S.H.,Lee, J.H.,Han, H.J. Elsevier 2014 Stem cell research Vol.12 No.1

Although recent findings showed that the bioactive lipid metabolites can regulate the ES cell functions, the physiological relevance of interaction between sphingosine-1-phosphate (S1P) and Flk-1 and its related signaling molecules are not yet clear in ES cell proliferation. In the present study, S1P<SUB>1-5</SUB> receptors were expressed in mouse ES cells and S1P increased S1P<SUB>1-3</SUB> receptor expression level. S1P treatment stimulated the cellular proliferation in S1P<SUB>1/3</SUB>-dependent manner, located in lipid rafts. In response to S1P, β-arrestin was recruited to S1P<SUB>1/3</SUB> receptor and c-Src was activated. S1P also increased the binding of S1P<SUB>1/3</SUB> receptor with Flk-1. Similar to responses for VEGF, S1P increased Flk-1 phosphorylation, which was blocked by β-arrestin siRNA, and PP2, but not by VEGF-A<SUB>164</SUB> antibody or VEGF siRNA. In addition, S1P induced VEGF expression and VEGFR2 kinase inhibitor (SU1498) blocked the S1P-induced cellular proliferation. However, VEGF-A<SUB>164</SUB> antibody or VEGF siRNA partially blocked S1P-induced cellular proliferation, suggesting that both VEGF-dependent Flk-1 activation and VEGF-independent Flk-1 activation are involved in S1P-induced ES cell proliferation. S1P and VEGF-induced phosphorylation of ERK and JNK were blocked by pretreatment with SU1498. Moreover, inhibition of ERK and JNK blocked S1P-induced cellular proliferation. In conclusion, S1P-elicited transactivation of Flk-1 mediated by S1P<SUB>1/3</SUB>-dependent β-arrestin/c-Src pathways stimulated mouse ES cell proliferation.

Performance and carrier transport analysis of In_0.7Ga_0.3As quantum-well MOSFETs with Al₂O₃/HfO₂ gate stack

Son, S.W.,Park, J.H.,Baek, J.M.,Kim, J.S.,Kim, D.K.,Shin, S.H.,Banerjee, S.K.,Lee, J.H.,Kim, T.W.,Kim, D.H. Pergamon Press ; Elsevier Science Ltd 2016 Solid-State Electronics Vol.123 No.-

In this paper, we have fabricated and characterized In<SUB>0.7</SUB>Ga<SUB>0.3</SUB>As quantum-well (QW) metal-oxide-semiconductor field-effect-transistors (MOSFETs). We have employed the gate dielectric of the Al<SUB>2</SUB>O<SUB>3</SUB>/HfO<SUB>2</SUB> (0.6/2nm) bi-layer stack by ALD. The fabricated device with L<SUB>g</SUB>=4μm exhibits a record maximum transconductance (g<SUB>m_max</SUB>) in excess of 520μS/μm at >1μm region, and reasonably good electrostatic integrity, such as SS=110mV/decade and DIBL=43mV/V. Also, we have investigated the gate length scaling behavior in terms of output, transconductance, and transfer characteristics. In particular, our devices feature very uniform values of the electrostatic integrity, such as SS=100-110mV/decade, V<SUB>T</SUB>=-0.25V to -0.2V and DIBL=40-50mV/V, as L<SUB>g</SUB> decreases from 10μm to 4μm. Furthermore, we have explored the impact of source resistance (R<SUB>S</SUB>) onto the device characteristics of the InGaAs QW MOSFETs. In doing so, we have modeled both measured extrinsic transconductance (g<SUB>m_ext</SUB>) and intrinsic transconductance (g<SUB>m_int</SUB>) as a function of L<SUB>g</SUB>.

Multicenter phase II study of docetaxel plus oxaliplatin combination chemotherapy in patients with advanced gastric cancer: Daegu Gyeongbuk Oncology Group

Kim, J G,Sohn, S K,Chae, Y S,Song, H S,Kwon, K-Y,Do, Y R,Kim, M K,Lee, K H,Hyun, M S,Ryoo, H M,Bae, S H,Park, K U,Lee, W S,Baek, J H,Chung, H Y,Yu, W Nature Publishing Group 2008 The British journal of cancer Vol.98 No.3

<P>The present study was conducted to evaluate the efficacy and safety of a combination regimen of docetaxel plus oxaliplatin in patients with advanced gastric cancer. Patients with previously untreated metastatic or recurrent, measurable gastric cancer received intravenous docetaxel 65 mg m<SUP>−2</SUP> plus oxaliplatin 120 mg m<SUP>−2</SUP> on day 1 based on a 3-week cycle. Forty-two patients were enrolled in the current study, among whom 39 were assessable for efficacy and all assessable for toxicity. One complete response and 18 partial responses were confirmed, giving an overall response rate of 45.2% (95% confidence interval (CI); 31.7–59.7%). At a median follow-up of 7.7 months, the median time to progression and median overall survival was 5.7 (95% CI; 4.3–7.2) months and 9.9 (95% CI; 7.8–12.0) months, respectively. Grade 3/4 neutropenia occurred in 11 patients (26.1%) and febrile neutropenia was observed in four patients (9.5%). The common non-haematologic toxicity was fatigue (grade 1/2, 61.9%) and nausea (grade 1/2, 47.7%). The combination of docetaxel and oxaliplatin was found to be well tolerated and effective in patients with advanced gastric cancer.</P>

Quality factor improvement of MIS capacitor using side metal coating

Baek, S.J.,Kim, J.C.,Yook, J.M. Institution of Electrical Engineers 2018 Electronics letters Vol.54 No.8

<P>A simple process to improve the quality factor of metal-insulator-silicon (MIS) capacitors is introduced. Typically, MIS capacitors show a low quality factor in the gigahertz range because the lower electrode is silicon, which has low conductivity. The electrical conductivity of the lower electrode of the MIS capacitor is improved by the application of side metal coating through a simple process. To make the side metal of the MIS capacitor, a 200 mu m-deep trench is formed between each capacitor using a sawing machine, and then the top electrode and side metal coating are added at the same time. Since scribing is performed prior to realisation of the top electrode, no additional dicing process is required. The quality factor of the proposed capacitor is improved from 73.8 to 101.3 at 2 GHz just by the addition of the side metal electrode.</P>

Density Functional Theory Study of Conformation-Dependent Properties of Neutral and Radical Cationic <small>l</small>-Tyrosine and <small>l</small>-Tryptophan

Baek, K. Y.,Fujimura, Y.,Hayashi, M.,Lin, S. H.,Kim, S. K. American Chemical Society 2011 The Journal of physical chemistry A Vol.115 No.34

<P>Conformation-dependent properties of <SMALL>l</SMALL>-tyrosine and <SMALL>l</SMALL>-tryptophan in neutral and radical cations were studied by using the density functional theory (DFT) with a new density functional M05-2X. The results are compared with those obtained by using the conventional DFT (B3LYP). Results obtained by both types of DFT were in qualitative accord, including the existence of two conformational subgroups and their subgroup-dependent adiabatic ionization energy and hydrogen bonding. On the other hand, quantitative differences were found between the two DFT methods as well: the M05-2X method successfully reproduced experimental adiabatic ionization energy, whereas the B3LYP functional consistently yielded significantly lower values by 0.2–0.3 eV. More importantly, natural bond orbital (NBO) analysis for cationic conformers showed that all conformers of <SMALL>l</SMALL>-tyrosine and <SMALL>L</SMALL>-tryptophan undergo charge localization upon ionization regardless of the presence of intramolecular hydrogen bonding, unlike the case of <SMALL>l</SMALL>-phenylalanine that was treated earlier by other studies. Different degrees of charge localization among all three aromatic amino acids are explained by employing a simple model in which the aromatic amino acid is assumed to consist of two submoieties of distinct cationic core: the backbone and aromatic side chain. The difference in adiabatic ionization energy between these two submoieties is found to govern the degree of charge localization.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jpcafh/2011/jpcafh.2011.115.issue-34/jp200826z/production/images/medium/jp-2011-00826z_0008.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/jp200826z'>ACS Electronic Supporting Info</A></P>

Ultraviolet photodissociation spectroscopy of cold, isolated adenine complexes with a potassium cation

Baek, J.Y.,Choi, C.M.,Eun, H.J.,Park, K.S.,Choi, M.C.,Heo, J.,Kim, N.J. North Holland 2015 Chemical physics letters Vol.635 No.-

We obtain the ultraviolet photodissociation spectrum of adenine complexes with K<SUP>+</SUP> ion stored in a cold ion trap. The spectrum near the origin band of the S<SUB>0</SUB>-S<SUB>1</SUB> transition exhibits well-resolved vibronic bands, all of which are assigned from a single isomer by UV-UV hole-burning (HB) spectroscopy. Comparing the spectrum with theoretical spectra, we determine the structure of the isomer, where K<SUP>+</SUP> is bound not to 9H-adenine (A9) but to 7H-adenine (A7). We suggest that K<SUP>+</SUP>A7 ions are formed in solution through tautomerization, for which the energy barrier varies greatly depending on the binding site of the K<SUP>+</SUP> ion on A9.

Beyond the dark matter effective field theory and a simplified model approach at colliders

Baek, S.,Ko, P.,Park, M.,Park, W.I.,Yu, C. Elsevier 2016 Physics letters: B Vol.756 No.-

Direct detection of and LHC search for the singlet fermion dark matter (SFDM) model with Higgs portal interaction are considered in a renormalizable model where the full Standard Model (SM) gauge symmetry is imposed by introducing a singlet scalar messenger. In this model, direct detection is described by an effective operator m<SUB>q</SUB>q@?qχ@?χ as usual, but the full amplitude for monojet + E@?<SUB>T</SUB> involves two intermediate scalar propagators, which cannot be seen within the effective field theory (EFT) or in the simplified model without the full SM gauge symmetry. We derive the collider bounds from the ATLAS monojet + E@?<SUB>T</SUB> as well as the CMS tt@?+E@?<SUB>T</SUB> data, finding out that the bounds and the interpretation of the results are completely different from those obtained within the EFT or simplified models. It is pointed out that it is important to respect unitarity, renormalizability and local gauge invariance of the SM.

Decrosslinking reaction kinetics of silane-crosslinked polyethylene in sub- and supercritical fluids

Baek, B.K.,La, Y.H.,Lee, A.S.,Han, H.,Kim, S.H.,Hong, S.M.,Koo, C.M. Applied Science Publishers ; Elsevier Science Ltd 2016 Polymer degradation and stability Vol.130 No.-

Supercritical methanol is a popular fluid as a supercritical medium for decrosslinking reaction of crosslinked polyethylene. However, due to its toxicity, a safe alternative medium is much to be desired. In this work, various sub- and supercritical fluids with different polarity characters were investigated to find a safe alternative medium for continuous decrosslinking of silane-crosslinked polyethylene (S-XLPE). Like methanol, all examined fluids, including ethanol, propanol, and water, exhibited first-order reaction kinetics regarding the gel content in the continuous decrosslinking process. The reaction rate constant values were observed as 2.806, 2.569, 2.383, and 2.130 min<SUP>-1</SUP> in supercritical methanol, supercritical ethanol, supercritical 2-propanol, and subcritical water at 380 <SUP>o</SUP>C, respectively. As a non-toxic fluid with reaction kinetics very comparable to that of methanol, ethanol was found to be the best alternative medium for the continuous decrosslinking reaction of S-XLPE.

M20J 시뮬레이터 개발을 위한 시스템 통합

홍승범,김용환,정식항,백중환,황수찬,황명신,김칠영 한국항공운항학회 1999 한국항공운항학회지 Vol.7 No.1

This paper proposes a system intergration method for M20J flight simulator development. The simulator consists of three modules. The first module is for flight dynamics simulation, and the second module is for avionic systems and flight instrument and the last module is for interface card which connects PC and input devices using rotary encoders and switches. Two computers are equipped in the simulator for instructor and trainee. An instructor can give a mission to a trainee, and control the flight simulation options through RS-232C serial port. Also, the instructor can monitor the training results of the trainee

A numerical study of the effectiveness factors of nickel catalyst pellets used in steam methane reforming for residential fuel cell applications

Baek, S.M.,Kang, J.H.,Lee, K.J.,Nam, J.H. Pergamon Press ; Elsevier Science Ltd 2014 INTERNATIONAL JOURNAL OF HYDROGEN ENERGY - Vol.39 No.17

A numerical study is performed to evaluate the effectiveness factors of commercial nickel catalyst pellets commonly used in small-scale steam methane reformers for residential fuel cell applications. Based on the intrinsic reaction kinetics of the steam reforming process, the standard composition of the partially reformed gas mixture is determined as a function of the methane conversion. The heterogeneous reforming reactions inside the spherical catalyst pellets are then modeled by considering the distributed reaction, multi-component diffusion and permeation, and conductive and convective heat transfer in the porous media. Various operating conditions, including the reforming temperature, steam-to-carbon (S/C) ratio, operating pressure, and geometrical parameters, such as the pellet diameter and mean pore size, are simulated. The effectiveness factors calculated for each condition are presented as a function of the methane conversion. Finally, simple correlations for the effectiveness factors are presented, and their accuracies are assessed.