• Bulletin of the Korean Chemical Society
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• v.12 no.3
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• pp.286-289
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• 1991

The changed isotropic absolute Raman intensities of the phosphate residue in the complexes of positive charge oligopeptides, lys-lys, arg-arg, lys-aromat-lys, negative charge diethyl phosphoric acid (DEP) and polyriboadenylic acid{poly(rA)} were reported and discussed. Our measurements showed that the absolute intensities of phosphate stretch vibration in complexes were different according to the reaction partners. Due to the partial electrical charge and molecular structure of oligopeptides for the complex formation lysine can interact more strongly than arginine when the reaction partners have short chain and no steric hindrance. Owing to these reasons the intensity of phosphate stretching vibration is very sensitive according to the circumstance of reaction. From our results we could suggest that we can discriminate any one of the the lysine and arginine in the complicated biological molecule during interaction between nucleotides and proteins. The activity of reaction of two basical oligopeptides is not quite similar for complex formation in aqueous solution. The activity of dipeptides depends upon the structure of molecule and environment for complex formation. Aromatic ring contributes to electrostatic interaction in complexes. The amount of the absolute intensity for pure stacking interaction is smaller than electrostatic interaction in macromolecular complexes.

• Korean Chemical Engineering Research
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• v.43 no.2
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• pp.313-317
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• 2005

Synthetic gene carriers such as poly-cationic polymers easily form complexes with plasmid DNA which contains negative charge. Chitosan is a polysaccharide that demonstrates much potential as a gene delivery system. The ability of depolymerized chitosan to condense DNA was determined using electrophoresis. Dynamic laser scattering and scanning electron microscopy were used to examine the size and the morphology of the chitosan/DNA complex. Parameters such as chitosan molecular weight and charge density influenced the complex size and the DNA amount condensed with chitosan. The cell viabilities in the presence of chitosan ranged between 84-108% of the control in all experiments. Gene expression efficacy using chitosan/DNA complex was enhanced in 293 cells relative to that using naked DNA, although it was lower than that using lipofecamine. Transfection efficacy using low molecular weight chitosan (Mw=8,517) was higher than those of the control and the other chitosan (MW=4,078). The low molecular weight chitosan (MW=8,517) with a high charge density (18.32 mV) fulfilled the requirements for a suitable model gene delivery system with respect to the condensing ability of DNA, complex formation, and transfection efficacy.

• Rapid Communication in Photoscience
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• v.5 no.1
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• pp.1-7
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• 2016

Fluorescent receptors have gained much attention because of their usefulness in analysis and clarification of the roles of biomolecules in living systems. Molecular structures of the integrated type including that the receptor itself is fluorescent, and play an important role in having the functionality or selectivity of the fluorescent compounds. These spaced type fluorescent receptors are required to have special molecular design in order to transmit the information of molecular recognition to the fluorescent unit through the spacer unit. Compared with the spaced type fluorescent receptors, number of the integrated type receptors is limited due to the difficult molecular design and synthesis. Modification of alteration of the fluorophore frequently caused deterioration of the fluorescent property. Various spaced type and integrated type fluorescent receptors including switch on-off receptors are introduced in this article.

• Bulletin of the Korean Chemical Society
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• v.17 no.2
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• pp.147-152
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• 1996

To see the quantitative relationship between the structures of the C-7 substituted quinolones and their antibacterial activities, theoretical parameters such as the molecular van der Waals volume, surface area and some electrostatic parameters based on the molecular electrostatic potential, which represent lipophilicity, and some quantum mechanical parameters are introduced as descriptors. The sixteen substituted quinolone derivatives and twenty bacteria are used for the study. It is found that the QSARs of C-7 substituted quinolones are obtained for eleven bacteria and our descriptors are more useful for Gram positive organisms than negative ones. It is also shown that molecular surface area (or molecular Waals volume) of the C-7 substituent and net charge of C-7 atom of the quinolones are the descriptors of utmost importance.

• Bulletin of the Korean Chemical Society
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• v.31 no.9
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• pp.2531-2536
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• 2010

Density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations have been employed to investigate the molecular structures and absorption spectra of two dyes containing diphenylaniline and 4-diphenylamino-diphenylaniline as donor moiety (TPA1 and TPA3). The geometries indicate that the strong conjugation is formed in the dyes. The electronic structures suggest that the intramolecular charge transfer from the donor to the acceptor occurs, and the electron-donating capability of 4-diphenylamino-diphenylaniline is stronger than that of diphenylaniline. The computed highest occupied molecular orbital (HOMO) energy levels are -5.31 and -4.90 eV, while the lowest unoccupied molecular orbital (LUMO) energies are -2.29 and -2.26 eV for TPA1 and TPA3, respectively, revealing that the interfacial charge transfer between the dyes and the semiconductor electrode are electron injection processes from the photon-excited dyes to the semiconductor conduction band. Furthermore, all the experimental absorption bands of TPA1 and TPA3 have been assigned according to the TDDFT calculations.

• Journal of Korea Multimedia Society
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• v.9 no.12
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• pp.1580-1587
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• 2006

The term molecular imaging can be broadly defined as the in vivo characterization and measurement of biologic processes at the cellular and molecular level. Optical imaging that has highly reproducibility and repetition used in molecular imaging research. In the bioluminescence imaging, animals carrying the luciferase gene are imaged with a cooled CCD(Charge-Coupled Device) camera to pick up the small number of photons transmitted through tissues. Molecular imaging analysis will allow us to observe the incipience and progression of the disease. But hardware device for molecular imaging and software for molecular image analysis were dependent on imports. In this paper, we suggest image processing methods and designed software for bioluminescence signal analysis. And we demonstrated high correlation(r=0.99) between our software's photon counts and commercial software's photon counts. ROI function and processing functions were accomplished without error. This study have the importance of the development software for bioluminescence image processing and analysis. And this study built the foundations for creative development of analysis methods. We expected this study lead the development of image technology.

• Journal of Environmental Science International
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• v.11 no.2
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• pp.93-102
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• 2002

Using a simple continuous optical technique, coupled with measurements of zeta potential, the flocculation characteristics of kaoline suspensions of different content(15, 35 and 55 NTU) by several cationic polyelectrolytes, has been examined. The optimum mixing is obtained under a constant stirring of 200 rpm, differently from a general flocculation test. The charge density of a polyelectrolyte is important in determining the optimum dosage and in the removal of kaoline particles. The optimum dosage is less for the polyelectrolyte of higher charge density and is the same regardless of kaoline content. At the dosage, the removal of kaoline particles is higher for the polyelectrolyte of higher charge density and zeta potential of kaoline particles reaches to near zero. The rate of adsorption and flocculation rate have been found to be affected by charge density and molecular weight of a polyelelctrolyte and the content of kaoline particles.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2008.10a
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• pp.291-298
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• 2008

• Proceedings of the Korean Vacuum Society Conference
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• 2008.02a
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• pp.161-161
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• 2008

• Proceeding of EDISON Challenge
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• 2013.04a
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• pp.221-223
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• 2013

Self-assembly of the molecular system of perylene-3,4,9,10-tetracarboxylic-3,4,9,10-dianhydride (PTCDA) and the amide analogue (PTCDI) is of potential importance for organic semiconductor devices. Therefore we studied the density of states (DOS), the charge densities, and intermolacular bond lengths for PTCDA and PTCDI using the density functional theory calculations.