• Title/Summary/Keyword: $\pi$-$\pi$ interaction

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Study on Service Identity and Identity Framework

  • Kang, Hwa-Sun;Pan, Young-Hwan
    • Journal of the Ergonomics Society of Korea
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    • v.31 no.1
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    • pp.33-40
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    • 2012
  • Objective: Service industry has become the most important industry among various economic activities, as the percentage of service related industry in advanced nations is over 60% of their GDP and the percentage of service industry in South Korea, a traditional manufacturing nation, now takes up over 60% of the entire economy. Background: Such industry paradigm shift has changed consumers from those that simply purchased products into groups of people that evaluate the companies that manufacture products, thereby further intensifying competition among companies and increasing the importance of integrated communication between companies and consumers. However, the excessive existence of sub-identities that have been developed for integrated management of the existing corporate identities, as well as the undifferentiated general management strategies by companies are creating confusion not only for consumers but also for various corporate interest parties. In addition, service identity strategy has become the most important strategy than any other sub-identity strategies in forming corporate identity at the increased importance of corporate service in the era of service industry. However, the current domestic circumstance is that the concept of service identity has not been well established through specific related studies. Method: Accordingly, the existing academic and field studies on the corporate identity(CI), brand identity(BI) and product identity(PI) used for the communication with consumers were reviewed in this study to establish and summarize the concept of service identity(SI) that appeared at the service economization. Results: The purpose is to examine the kind of change that could be brought about by SI for the corporate integrated identity strategy developed through the existing corporate, brand & product image in order to present a new direct in corporate identity strategy according to the industry paradigm shift through a SI centered new corporate identity framework. Conclusion: For preparing the new era of service industry, the corporate integrated identity strategy must be integrate with concept of service identity and which is essential to differential from other companies. Application: The proposed concept and framework of service identity on this paper will help to understand and clearly define why service identity is important factor of the new idea of corporate identities.

Kinetics and Mechanism of the Benzylaminolysis of O,O-Diphenyl S-Aryl Phosphorothioates in Dimethyl Sulfoxide

  • Adhikary, Keshab Kumar;Lee, Hai-Whang
    • Bulletin of the Korean Chemical Society
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    • v.32 no.5
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    • pp.1625-1629
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    • 2011
  • Kinetic studies of the reactions of O,O-diphenyl Z-S-aryl phosphorothioates with X-benzylamines have been carried out in dimethyl sulfoxide at 55.0 $^{\circ}C$. The Hammett (log $k_2$ vs ${\sigma}_X$) and Bronsted [log $k_2$ vs $pK_a(X)$] plots for substituent X variations in the nucleophiles are biphasic concave downwards with a maximum point at X = H, and the unusual positive ${\rho}_X$ and negative ${\beta}_X$ values are obtained for the strongly basic benzylamines. The sign of the cross-interaction constant (${\rho}_{XZ}$) is negative for both the strongly and weakly basic nucleophiles. Greater magnitude of ${\rho}_{XZ}$ value is observed with the weakly basic nucleophiles (${\rho}_{XZ}$ = -2.35) compared to with the strongly basic nucleophiles (${\rho}_{XZ}$ = -0.03). The deuterium kinetic isotope effects ($k_H/k_D$) involving deuterated benzylamines [$XC_6H_4CH_2ND_2$] are primary normal ($k_H/k_D$ > 1). The proposed mechanism is a concerted $S_N2$ involving a frontside nucleophilic attack with a hydrogen bonded, four-center-type transition state for both the strongly and weakly basic nucleophiles. The unusual positive ${\rho}_X$ and negative ${\beta}_X$ values with the strongly basic benzylamines are rationalized by through-space interaction between the ${\pi}$-clouds of the electron-rich phenyl ring of benzylamine and the phenyl ring of the leaving group thiophenoxide.

Kinetics and Mechanism of the Addition of Benzylamines to β-Cyanostilbenes in Acetonitrile

  • Oh, Hyuck-Keun;Kim, In-Kon;Sung, Dae-Dong;Lee, Ik-Choon
    • Bulletin of the Korean Chemical Society
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    • v.26 no.4
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    • pp.641-644
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    • 2005
  • Nucleophilic addition reactions of benzylamines $(XC_6H_4CH_2NH_2)\;to\;{\beta}$-cyanostilbenes ($YC_6H_4CH=C(CN)C_6H_4$Y’) have been studied in acetonitrile at 30.0 oC. A greater degree of N-$C_{\alpha}$ bond formation (larger ${\beta}_X$) is obtained with a stronger electron-withdrawing substituent in either ${\alpha}-\;(\delta\sigma_Y\;{\gt}\;0)\;or\;{\beta}-ring\;(\delta\sigma_{Y'}\;{\gt}$ 0). A stronger charge development is observed in the TS on $C_{\beta}\;(\rho_{Y'}$= 1.06 for X=Y=H) rather than on $C_{\alpha}\;(\rho_{Y}$ = 0.62 for X=Y’H) indicating the lag in the resonance development into the activating group (CN) on $C_{\beta}$ in the transition state. Similarly, the magnitude of $\rho$$_{XY'}$(−0.72) is greater than $\rho_{XY}$ (−0.66) due to a stronger interaction of the nucleophile with $\beta$-ring than $\alpha$-ring. The positive sign of $\rho_{YY'}$correctly reflects $\pi$ bond cleavage between the two rings in the TS. Relatively large kinetic isotope effects ($k_H/k_D\;{\geq}$ 2.0) involving deuterated nucleophiles ($XC_6H_4CH_2ND_2$) suggest a four-membered cyclic TS in which concurrent N-C$_{\alpha}$ and H(D)-C$_{\beta}$ bond formation occurs.

Development of ELISA System for Screening of Specific Binding Inhibitors for Src Homology (SH)2 Domain and Phosphotyrosine Interactions

  • Lee, Sang-Seop;Lee, Kyung-Im;Yoo, Ji-Yun;Jeong, Moon-Jin;Park, Young-Mee;Kwon, Byoung-Mog;Bae, Yun-Soo;Han, Mi-Young
    • BMB Reports
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    • v.34 no.6
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    • pp.537-543
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    • 2001
  • In the present study, an in vitro ELISA system to assess the interaction between Src homology (SH)2 domains and phosphotyrosine that contain peptides was established using purified GST-conjugated SH2 proteins and synthetic biotinylated phosphotyrosine that contain oligopeptides. The SH2 domains bound the relevant phosphopeptides that were immobilized in the streptavidin-coated microtiter plate in a highly specific and dose-dependent manner. The epidermal growth factor receptor (EGFR)-, T antigen (T Ag)-, and platelet-derived growth factor receptor (PDGFR)-derived phosphopeptides interacted with the growth factor receptor binding protein (Grb)2/SH2, Lck/SH2, and phosphatidyl inositol 3-kinase (PI3K) p85/SH2, respectively. No cross-reactions were observed. Competitive inhibition experiments showed that a short phosphopeptide of only four amino acids was long enough to determine the binding specificity. Optimal concentrations of the GST-SH2 fusion protein and phosphopeptide in this new ELISA system for screening the binding blockers were chosen at 2nM and 500nM, respectively. When two candidate compounds were tested in our ELISA system, they specifically inhibited the Lck/SH2 and/or p85/SH2 binding to the relevant phosphopeptides. Our results indicate that this ELISA system could be used as an easy screening method for the discovery of specific binding blockers of protein-protein interactions via SH2 domains.

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Effect of Cirsii Japonici Herba on LPS-induced Inflammation in Mouse BV2 Microglial cells (대계(大薊)가 LPS로 유도된 Mouse BV2 Microglial cells의 염증반응에 미치는 영향)

  • Kim, Young-Sun;Lee, Seoung-Geun;Lee, Key-Sang
    • The Journal of Internal Korean Medicine
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    • v.29 no.4
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    • pp.1048-1060
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    • 2008
  • Cirsii Japonici Herba(CJ) is a wild perennial herb found in many areas of Korea as well as China and Japan, which has been used to treat bleeding and inflammation. Silibinin is the main flavonoid extracted from milk thistle (Cirsii Japonici Herba). It exhibits potent antioxidant activity and anti-inflammatory effect. In this study, the effect of CJ and silibinin extract on lipopolysaccharide-induced inflammation was investigated using MTS assay, RT-PCR, western blot, and nitric oxide detection on mouse BV2 microglial cell lines. In the present results, CJ and silibinin extract suppressed nitric oxide production by inhibiting the lipopolysaccharide-stimulated enhancement of COX-2 and iNOS gene expression in BV2 cells. Moreover, CJ and silibinin also repressed some lipopolysaccharide-induced signaling molecules. Importantly, catalase-induced COX-2 and iNOS expression needed activations of $NF-{\kappa}B$, PI3K/Akt, and MAPK, which were important for the transcriptional up-regulation of COX-2 and iNOS. CJ and silibinin interaction on BV2 cells down-regulated $NF-{\kappa}B$-dependent proinflammatory cytokine (IL-2,IL-6) expression. They are involved in the regulation of inflammatory responses. These data shows that CJ and silibinin exerts anti-inflammatory and analgesic effects, probably by suppression of COX-2 and iNOS synthase expression in BV2 microglial cells.

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Kinetics and Mechanism of the Pyridinolysis of Aryl Ethyl Chlorothiophosphates in Acetonitrile

  • Adhikary, Keshab Kumar;Lee, Hai-Whang
    • Bulletin of the Korean Chemical Society
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    • v.32 no.11
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    • pp.3947-3951
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    • 2011
  • The nucleophilic substitution reactions of Y-aryl ethyl chlorothiophosphates with X-pyridines are studied kinetically in acetonitrile at $55.0^{\circ}C$. The Hammett and Bronsted plots for substituent X variations in the nucleophiles exhibit biphasic concave upwards with a break point at X = 3-Me. The substituents of X = 4-CN and 4-Ac show great positive deviations from both the Hammett and Bronsted plots. The Hammett plots for substituent Y variations in the substrates exhibit biphasic concave upwards with a minimum point at Y = H. The obtained values of the cross-interaction constants (${\rho}_{XY}$) are all in spite of the biphasic free energy correlations for both substituent X and Y variations, since the ${\rho}_X$values with both the strongly and weakly basic pyridines are almost constant. A stepwise mechanism with a rate-limiting leaving group departure from the intermediate is proposed where the distance between X and Y does not vary from the intermediate to the second transition state. A frontside attack is proposed with the strongly basic pyridines based on the considerably great magnitudes of ${\rho}_X$ and ${\beta}_X$ values and a backside attack is proposed with the weakly basic pyridines based on the relatively small magnitudes of ${\rho}_X$ and ${\beta}_X$. The positive deviations of the two strong ${\pi}$-acceptor parasubstituents, X = 4-Ac and 4-CN, from both the Hammett and Bronsted plots are rationalized by the great extents of bond formation and breaking.

Electronic Properties and Conformation Analysis of π-Conjugated Distyryl Benzene Derivaties

  • Kim, Cheol-Ju
    • Bulletin of the Korean Chemical Society
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    • v.23 no.2
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    • pp.330-336
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    • 2002
  • A quantum-chemical investigation on the conformations and electronic properties of bis[2-{2-methoxy-4,6-di(t-butyl)phenyl}ethenyl]benzenes (MBPBs) as building block for ${\pi}$-conjugate polymer are performed in order to display the effects of t-butyl and methoxy group substitution and of kink(ortho and meta) linkage. The conjugation length of the polymers can be controlled by substituents and kink linkages of backbone. Structures for the molecules, o-, m-, and p-MBPBs as well as unsubstituted o-, m-, and p-DSBs were fully optimized by using semiempirical AM1, PM3 methods, and ab initio HF method with 3-21G(d) basis set. The potential energy curves with respect to the change of single torsion angle are obtained by using semiempirical methods and ab initio HF/3-21G(d) basis set. The curves are similar shape in the molecules with respect to the position of vinylene groups. It is shown that the conformations of the molecules are compromised between the steric repulsion interaction and the degree of the conjugation. Electronic properties of the molecules were obtained by applying the optimized structures and geometries to the ZINDO/S method. ZINDO/S analysis performed on the geometries obtained by AM1 method and HF/3-21G(d) level is reported. The absorption wavelength on the geometries obtained by AM1 method is much longer than that by HF/3-21G(d) level. The absorption wavelength of MBPBs are red shifted with comparison to that of corresponding DSBs in the same torsion angle because of electron donating substituents. The absorption wavelength of isomers with kink(orth and meta) linkage is shorter than that of para linkage.

Development of Transmission Expansion Planning Optimization Software Considering Integration of Generation and Transmission Facilities (발·송전설비 통합성을 고려한 전력계통계획 전산모형 프로그램 개발)

  • Hur, Don;Jung, Hae-Sung;Ryu, Heon-Su;Cho, Kong-Wook
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.24 no.2
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    • pp.16-26
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    • 2010
  • The transmission valuation methodology we propose here captures the interaction between generation and transmission investment decisions recognizing that a transmission expansion can impact the profitability of new resources investment, so that a methodology should consider both the objectives of investors in resources and the transmission planner. In this perspective, this paper purports to develop the mixed-integer programming based transmission expansion planning optimization software, which is well designed to determine the construction time and place of new generators, transmission lines, and substations as well as their capacities to minimize total expenditures related to their investment and operations while meeting technical constraints such as capacity margin, constitution ratio of power resources, spinning reserves, energy and fuel constraints, transmission line outages and losses, pi-type branching, and so on. Finally, Garver's simple system is adopted to validate not simply the accuracy but the efficiency of the proposed model in this paper.

Adsorption Characteristics and Structure of 4,4'-Bis(mercaptomethyl)biphenyl on Silver by Surface-enhanced Raman Scattering and Density Functional Theory Calculations

  • Eom, So Young;Lee, Yu Ran;Kim, Hong Lae;Kwon, Chan Ho
    • Bulletin of the Korean Chemical Society
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    • v.35 no.3
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    • pp.875-880
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    • 2014
  • Adsorption of 4,4'-bis(mercaptomethyl)biphenyl (44BMBP) on silver nanoparticles has been investigated by surface-enhanced Raman scattering (SERS) spectroscopy. In addition, the Raman spectra of 44BMBP in solid state and in basic condition have been obtained for comparative study to elicit the characteristics of adsorption. The observed Raman and SERS spectra were analyzed comparing with the normal modes and vibrational frequencies from density functional theory (DFT) calculations performed for the feasible structures of 44BMBP molecule. On the basis of excellent agreement between the calculated and the experimental results, the molecule is found to have both the cis- and trans-forms for the mercaptomethyl groups in the solid state as well as in the basic condition. In contrast, the molecule is found to be chemisorbed on the silver surface by forming two Ag-S linkages only in the cis-form but not in the trans-form due to the steric interruption, which indicates the parallel orientation of molecules on the surface. Particularly, the spectral features in the SERS spectra such as the absence of the C-H stretching band and enhancement for the out-of-plane skeletal modes are confirmatory for the parallel geometry through ${\pi}$ interaction between the phenyl rings and the metal surface, based on the electromagnetic surface selection rule.

Pressure Control of Hydraulic Pump using SR Drive with Pressure Predict and Direct Torque Control Method (압력예측기법과 직접순시토크제어기법을 통한 유압펌프용 SRM의 압력제어구동)

  • Lee, Dong-Hee;Seok, Seung-Hun;Liang, Jianing;Ahn, Jin-Woo
    • The Transactions of the Korean Institute of Power Electronics
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    • v.13 no.3
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    • pp.171-178
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    • 2008
  • Pressure control of hydraulic pump using SRM with pressure predictor and direct torque control method is presented in this paper. Nowadays, high efficiency and high performance motor drive is much interested in hydraulic pump system. But the hydraulic pump system has an inherent defect that its dynamic behavior causes by interaction between the sensor and hydraulic load. It will make low performance of whole system, even unstable and oscillatory. Proposed system integrates pressure predictor and direct instantaneous torque control (DITC). The pressure predictor includes Smith predictor, which is easy to improve unstable or long oscillation in traditional negative feedback control and popular PID control architectures. And DITC method can reduce inherent torque ripple of SRM, and develop smooth torque to load, which can increase stability and improve the torque response of SR drive. So high dynamic performance and stabilization can achieved proposed hydraulic system. At last, the proposed hydraulic system is verified by simulation and experimental results.