• Journal of the Korean Magnetic Resonance Society
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• v.11 no.2
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• pp.85-94
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• 2007

Vanilloid receptor I [transient receptor potential vanilloid subfamily member 1 (TRPV1), also known as VR1] is a non-selective cationic channel activated by noxious heat, vanilloids, and acid, thereby causing pain. VR1 possesses six transmembrane domain and N-and C-terminus cytosolic domains, and appears to be a homotetramer. We studied the structural properties of Cterminus of VR1 (VR1C) using CD and NMR spectroscopy. DPC micelles, with a zwitterionic surface, and SDS micelles, with a negatively charged surface, were used as a membrane mimetic model system. Both SDS and DPC micelles could increase the stability of helical structures and/or reduce the aggregation form of the VR1C. However, the structural changing mode of the VR1C induced by the SDS and DPC micelles was different. The changes according to the various pHs were also different in two micelles conditions. Because the net charges of the SDS and DPC micelles are negative and neutral, respectively, we anticipate that this difference might affect the structure of the VR1C by electrostatic interaction between the surface of the VR1C and phospholipids of the detergent micelles. Based on these similarity and dissimilarity of changing aspects of the VR1C, it is supposed that the VR1C probably has the real pI value near the pH 7. Generally, mild extracellular acidic pH ($6.5{\sim}6.8$) potentiates VRI channel activation by noxious heat and vanilloids, whereas acidic conditions directly activate the channel. The channel activation of the VRI might be related to the structural change of VR1C caused by pH (electrostatic interactions), especially near the pH 7. By measuring the $^1-^{15}N$ TROSY spectra of the VR1C, we could get more resolved and dispersed spectra at the low pH and/or detergent micelles conditions. We will try to do further NMR experiments in low pH with micelles conditions in order to get more information about the structure of VR1C.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.4
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• pp.85-92
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• 2018

Reductions of the electricity charge are achieved by demand management of the load. The demand management method of the load using ESS involves peak shifting, which shifts from a high demand time to low demand time. By shifting the load, the peak load can be lowered and the energy charge can be saved. Electricity charges consist of the energy charge and the basic charge per contracted capacity. The energy charge and peak load are minimized by Linear Programming (LP) and Quadratic Programming (QP), respectively. On the other hand, each optimization method has its advantages and disadvantages. First, the LP cannot separate the efficiency of the ESS. To solve these problems, the charge and discharge efficiency of the ESS was separated by Mixed Integer Linear Programming (MILP). Nevertheless, both methods have the disadvantages that they must assume the reduction ratio of peak load. Therefore, QP was used to solve this problem. The next step was to optimize the formula combination of QP and LP to minimize the electricity charge. On the other hand, these two methods have disadvantages in that the charge and discharge efficiency of the ESS cannot be separated. This paper proposes an optimization method according to the situation by analyzing quantitatively the advantages and disadvantages of each optimization method.

• Journal of the Korean Chemical Society
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• v.41 no.3
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• pp.117-122
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• 1997

On the basis of our previous paper[Bull. Korean Chem. Soc. 1995, 16, 1015], the relative stability, ionization potential, and chemical reaction of the neutral and multiply charged $C_{60}$n ions(n=3+ to 6-) have been investigated by the semi-empirical MNDO method. $C_{60}^{1-}$ has the highest stability. The ionization potential values of the $C_{60}$ ions range from 15.31 eV of $C_{60}^{2+}$ to -13.01 eV of $C_{60}^{6-}$. These values show a linear relationship according to charges. The average IP per charge is 3.15 eV from our calculations and 3.22 eV from the linear function of IP. A charge- or electron-transfer reaction of $C_{60}^{n+}$ will only occur if the ionization potential of any guest molecule is lower than the electron affinity of the host $C_{60}^{n+}$. If the energy gap between ionization potential and electron affinity, ${\Delta}_{IP-EA}$, is high, charge-transfer reactions arise by the charge-controlled effect. However, if ${\Delta}_{IP-EA}$ is low, electron-transfer reactions arise by the frontier-controlled effect.

• Journal of the Korean Chemical Society
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• v.41 no.6
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• pp.277-283
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• 1997

Platinum(II) complexes(where, $[Pt(L)_2X_2]$; L=isoxazole(isox), 3,5-dimethylisoxazole(3,5-diMeisox), 3-methyl,5-phenylisoxazole(3-Me,5-Phisox), and 4-amino-3,5-dimethylisoxazole(4-ADI); X=Cl, Br) with planar ligands are investigated on antitumor activity by MM2 and EHMO calculations. It was found that, the net atomic charges of the halogen atoms in all of cis-, trans-isomers are greater than that of the nitrogen with planar form, indicating that ionic character of Pt-X bond is greater than that of Pt-N. Also, the ${\sigma}MO$ energy level($E{\sigma}_{(Pt-X)}$) of the interaction between $d_{x2-y2}$ orbital of Pt atom and $p_x$ orbital of X found to be higher than that of between $d_{x2-y2}$ orbital of Pt atom and $p_x$ orbital of N about all the complexes. It is found that bond strength of between Pt and X atom is weaker than that of between Pt and N atom. The ${\sigma}MO$ energy level($E{\sigma}_{(Pt-X)}$) of trans- complexes found to be higher than that of cis- complexes, as a result of bond strength of Pt-X in cis- and trans-complexes, for all the complexes. The degree of dissociation of X atom in Pt-X bond for trans-complexes are related to antitumor activity and the logIA value of inhibitory activity coefficient(IA).

• Journal of Korea Port Economic Association
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• v.24 no.1
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• pp.41-60
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• 2008

Korea has been doing a two-port system as a main port development policy and developing the port of Busan and Gwangyang as the transshipment hubs in the northeast Asia. However, the growth rate of the transshipment container volume of the Gwangyang port in 2007 was sharply dropping more than 31.4%. The reasons why reduced the growth rate of transshipment cargo were from the port development in north China and the direct callings of ships. Therefore, it is time to evaluate the transshipment hub port policy of Korea. This study would recognize the decision criteria of shipping companies as customers for the transshipment hub in the northeast Asia by the AHP methodology based on Lirn et al. (2004). It has been known the costs of shipping companies and port location as the main first tier criteria for transshipment ports, and container handling charges, closeness to the main navigation route, carriers' strategy, and nearness to the feeder ports as the important second tier factors. Finally, the domestic terminal operating companies would focus on only a few attributes including the terminal cost factor, but the international shipping companies would be considering more several factors than they do. Therefore, the transshipment port strategy should be enriched in the near future.

• Journal of Korea Port Economic Association
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• v.28 no.4
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• pp.275-298
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• 2012

Terminal operators have provided special services such as loading, discharging, stowage of cargo to the owner, and carriers of the sea, which contribute the domestic and international logistics. For smooth flow of logistics, container terminal should reserve spaces for inbound and outbound logistics. However, if it is unable to provide the spaces, which can be caused by labour strikes or terminal lockouts and so on, national logistic system and financial management of terminal operators can be seriously affected. In order to minimize these kinds of problems, terminal operators impose high rate of charges ("overstorage charge") to the accumulated cargoes and/or containers, which are stipulated in terminal service agreement. Nevertheless, if there is no terminal service agreement with an owner of cargo and/or container, any kind of charge can cause legal problems (conflict ??) between the cargo and terminal operator. In this regard, I would like to study on the definition of overstorage charge and the legal issue of it based on the Busan district court's judgment. In particular, I will propose a special right of commercial lien and public auction for terminal operators to settle accumulated cargoes in container terminal.

• Journal of Forest and Environmental Science
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• v.17 no.1
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• pp.47-61
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• 2001

The study was carried out to suggest the development scheme of Forestry Association by the method of member's consciousness inclination analysis. The results are as follows ; 1. Most of Association members perceived the necessity for re-education about cooperative association, especially the research suitable to the characteristics of Korea Forestry. 2. 59.9% of members had negative response against revision of Forestry Association Law, and 39.5% of members had negative opinion about taking exclusive charge of forest working by Forestry Association, noting the need of immediate publicity activities for those charges. 3. Large number of members pointed out that the most serious problems for the management of private forest were the budgetary deficit and the lack of joint marketing system of forest products. 25.9% of members had complaints about the management of their own forests after joining the association. 4. 34.0% of members opposed Proxy Management and 48.8% of members wanted Portion Consignment System. 5. The analysis noted that due to increase of the aged in rural communities, it is necessary to establish Forestry Working Corps, which is under the control of the Government and Forestry Association to supply forestry labor in a appropriate time. 6. Most of Association members liked establishment of Special Association for each forest products.

• Journal of the Microelectronics and Packaging Society
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• v.12 no.1 s.34
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• pp.35-40
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• 2005

The oxidation of pure Sn and Sn-0.7Cu, Sn-3.5Ag, Sn-lZn, and Sn-9Zn alloys at $150^{\circ}C$ was investigated. Both the chemical nature and the amount of oxides were characterized using electrochemical reduction analysis by measuring the electrolytic reduction potential and total transferred electrical charges. X-ray photoelectron spectroscopy (XPS) was also conducted to support the results of reduction analysis. The effect of Cu, Ag and Zn addition on surface oxidation of Sn alloys is reported. For Sn, Sn-0.7Cu and Sn-3.5Ag, SnO grew first and then the mixture of SnO and $SnO_2$ was found. $SnO_2$ grew predominantly for a long-time aging. For Zn containing Sn alloys, both ZnO and $SnO_2$ were formed. Zn promotes the formation of $SnO_2$. Sn oxide growth rate of Pb-free solder alloys was also discussed in terms of alloying elements.

• Journal of the Korean Chemical Society
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• v.62 no.1
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• pp.24-29
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• 2018

Despite the great potential for the versatile applications in food industry and medical area, chitosan as a biocompatible cationic polysaccharide has suffered from the limited solubility under physiological condition. Herein, we demonstrated the electrostatic formation of chitosan-based polyplex particles, counterbalanced by polyacrylate as an anionic polyelectrolyte. The resulting polyplex exhibited pH- and composition-dependent changes in their surface charges as measured by zeta potential, which can be employed to provide the interparticle repulsive forces for enhanced colloidal stability in homogeneous solution. Subsequently, amide coupling between the acrylates and glucosamine residues of chitosan inside the polyplex further generated the hydrogel particles, which showed the temperature-sensitive swelling property. This aspect can be attributed to the partial formation of acryl amide residues, which have been generally known to possess the lower critical solution temperature (LCST).

• Bulletin of the Korean Chemical Society
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• v.32 no.8
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• pp.2577-2583
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• 2011

We have designed a 20-residue hybrid peptide CA(1-8)-MA(1-12) (CAMA) incorporating residues 1-8 of cecropin A (CA) and residues 1-12 of magainin 2 (MA) with high bacterial cell selectivity. CAMA-P2 is an ${\alpha}$-helical antimicrobial peptide designed from a CAMA hybrid peptide and substitution of Gly-Ile-Gly hinge sequence of CAMA to Pro influences the flexibility at central part of CAMA. Based on structure-activity relationships of CAMA peptides, to investigate the effects of the total positive charges on antimicrobial activity of CAMA-P2, the $Ser^{14}{\rightarrow}$Lys analogue (CAMA-syn1) was synthesized. The role of tryptophan at C-terminal ${\alpha}$-helix on its antimicrobial activity as well as synergistic activity was also investigated using $Ser^{14}{\rightarrow}$Lys/$Phe^{18}{\rightarrow}$Trp analogue (CAMA-syn2). Also, we designed CAMA-syn3 by substitution of $Lys^{16}$ located opposite side of substituted $Lys^{14}$ of CAMA-syn1 with Leu residue, resulting in increase of hydrophobicity and amphipathicity of the peptide. All of CAMA-syn analogues showed good antimicrobial activities similar to those of CAMA and CAMA-P2. The CAMA-syn1 and CAMA-syn2 showed low hemolytic activity and cytotoxicity against human keratinocyte Haca-T cells while CAMA-syn3 showed hemolytic activity and cytotoxicity at its MIC value. We then investigated their abilities to act synergistically in combination with the antimicrobial flavonoids and synthetic compounds screened in our laboratory. The results showed that all peptides exhibited synergistic effects with dihydrobinetin, while only CAMA-syn2 exhibited synergistic effects with YKAs3001 against both S. aureus and MRSA, suggesting that Trp residue at C-terminus of CAMA-syn2 may facilitate the polar antibiotic flavonoids and synthetic compounds to permeabilize the membrane. This study will be useful for the development of new antibiotic peptides with potent antimicrobial and synergistic activity but without cytotoxicity.