• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.202.2-202.2
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• 2014

We have studied the bonding structures of five membered aromatic ring heterocyclic molecules, such as furan, thiophene, and selenophene, adsorbed on the Si(100) surface at room temperature with density functional theory. Additionally, we have investigated the evolution upon annealing of thiophene and selenophene molecules on the Si(100) surface by the core-level photoemission spectroscopy and near-edge X-ray absorption fine structure (NEXAFS). The core-level-spectra measured at different temperatures are consistently interpreted in terms of various adsorption structures suggested by theoretical calculations. In this study, we found the most suitable structures by theoretical and experimental results considering room temperature and mild thermal annealing.

• EDISON SW 활용 경진대회 논문집
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• 제3회(2014년)
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• pp.115-125
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• 2014

We investigate dissociation of diatomic molecules and anions using density functional theory (DFT) and density-corrected density functional theory (DC-DFT). We scan the potential energy curve of CH, NH and NO neutral molecule and its anion with both DFT and DC-DFT (in form of Hartree-Fock DFT, HF-DFT) using various functionals. Using CCSD(T) results as reference, we perform the error decomposition scheme recently proposed by Kim et al. The results show while most neutrals are $functio{\acute{n}}al$ error $domi{\bar{n}}ating$ normal calculations, $CH^-$ and $NO^-$ anions are density-driven error dominating abnormal calculations. In case of $NH^-$, traditional DFT goes to a wrong dissociation limit indicating abnormality, but both HF-DFT and CCSD(T) results need further investigation due to the kinks on the curve.

• Bulletin of the Korean Chemical Society
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• 제24권11호
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• pp.1649-1654
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• 2003

We have investigated substituent effect on the stabilization energies, and nucleus-independent chemical shifts of pentafulvalenes and on the electronic structures of the corresponding polypentafulvalenes to design environmentally stable semiconductive or conductive polymers. Geometrical optimizations of the molecules were carried out at the density functional level of theory with B3LYP hybrid functional and 6-311+G(d) basis set. Stabilization energies were estimated using isodesmic and homodesmotic reactions. As a criterion of aromaticity nucleus-independent chemical shifts of the molecules were computed using GIAO approach. For the polymers the geometrical parameters were optimized through AM1 band calculations and the electronic structures were obtained through modified extended Huckel band calculations. It is found that strong electronwithdrawing substituents increase isodesmic and homodesmotic stabilization energies of pentafulvalene, though it does not increase the aromaticity. Nitro-substituted pentafulvalene is estimated to have stabilization energy as much as azulene. However, substitution either with electron-donating groups or with electronwithdrawing groups does not significantly affect the electronic structures of polypentafulvalene and poly (vinylenedioxypentafulvalene).

• Bulletin of the Korean Chemical Society
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• 제26권4호
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• pp.589-593
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• 2005

The solvation free energy of proton in methanol was calculated by B3LYP flavor of density functional calculations in combination with the Poisson-Boltzmann continuum solvation model. In order to check the adequacy of the computation level, the free energies of clustering in the gas phase were compared with the experimental data. The solvents were taken into account in a hybrid manner, i.e. one to five molecules of methanol were explicitly considered while other solvent molecules were represented with an implicit solvation model.

• Molecules and Cells
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• 제45권10호
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• pp.761-761
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• 2022

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2009년도 추계학술발표회
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• pp.43-43
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• 2009

• 대한약학회:학술대회논문집
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• 대한약학회 2000년도 NEW STRATEGY FOR DRUG DEVELOPMENT IN POST-GENOMIC ERA(대한약학회)
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• pp.55-56
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• 2000

• 한국염색가공학회지
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• 제19권2호
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• pp.32-35
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• 2007

Cyclodextrin is a cyclic oligosaccharid material which shows an ability to incorporate organic guest molecules inside their cavity area. Thus, this ${\beta}-cyclodextrin$ treatment on fiber substrates may provide the changed surface characteristics of the substrates such as solubility, chemical reactivity and spectral property. In this context, the aim of this present work is to make a bridge connection using hetero-bi-functional reactive dye between fiber substrates and ${\beta}-cyclodextrin$. In addition, the corresponding Berberine inclusion behaviors into the inner cavity of ${\beta}-cyclodextrin$ was examined. The %exhaustion of Berberine inclusion as a guest molecule within the ${\beta}-cyclodextrin$ was measured using UV-Vis spectrophotometer. The findings showed that the %exhaustion of Berberine inclusion increased with increasing the prepared dye bridge compound and ${\beta}-cyclodextrin$ host material.

• Bulletin of the Korean Chemical Society
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• 제33권5호
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• pp.1505-1508
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• 2012

Protein tyrosine phosphatase 1B (PTP1B) is a key factor in negative regulation of the insulin pathway, and is a promising target for the treatment of type-II diabetes, obesity and cancer. Herein, compound ($\mathbf{4}$) was first observed to have moderate inhibitory activity against PTP1B with an $IC_{50}$ value of $13.72{\pm}1.53{\mu}M$. To obtain more potent PTP1B inhibitors, we synthesized a series of chalcone derivatives using compound ($\mathbf{4}$) as the lead compound. Compound $\mathbf{4l}$ ($IC_{50}=3.12{\pm}0.18{\mu}M$) was 4.4-fold more potent than the lead compound $\mathbf{4}$ ($IC_{50}=13.72{\pm}1.53{\mu}M$), and more potent than the positive control, ursolic acid ($IC_{50}=3.40{\pm}0.21{\mu}M$). These results may help to provide suitable drug-like lead compounds for the design of inhibitors of PTP1B as well as other PTPs.

• Journal of Ginseng Research
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• 제40권4호
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• pp.366-374
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• 2016

Background: In this study, we screened and identified an endophyte JG09 having strong biocatalytic activity for ginsenosides from Platycodon grandiflorum, converted ginseng total saponins and ginsenoside monomers, determined the source of minor ginsenosides and the transformation pathways, and calculated the maximum production of minor ginsenosides for the conversion of ginsenoside Rb1 to assess the transformation activity of endophyte JG09. Methods: The transformation of ginseng total saponins and ginsenoside monomers Rb1, Rb2, Rc, Rd, Rg1 into minor ginsenosides F2, C-K and Rh1 using endophyte JG09 isolated by an organizational separation method and Esculin-R2A agar assay, as well as the identification of transformed products via TLC and HPLC, were evaluated. Endophyte JG09 was identified through DNA sequencing and phylogenetic analysis. Results: A total of 32 ${\beta}$-glucosidase-producing endophytes were screened out among the isolated 69 endophytes from P. grandiflorum. An endophyte bacteria JG09 identified as Luteibacter sp. effectively converted protopanaxadiol-type ginsenosides Rb1, Rb2, Rc, Rd into minor ginsenosides F2 and C-K, and converted protopanaxatriol-type ginsenoside Rg1 into minor ginsenoside Rh1. The transformation pathways of major ginsenosides by endophyte JG09 were as follows: $Rb1{\rightarrow}Rd{\rightarrow}F2{\rightarrow}C-K$; $Rb2{\rightarrow}C-O{\rightarrow}C-Y{\rightarrow}C-K$; $Rc{\rightarrow}C-Mc1{\rightarrow}C-Mc{\rightarrow}C-K$; $Rg1{\rightarrow}Rh1$. The maximum production rate of ginsenosides F2 and C-K reached 94.53% and 66.34%, respectively. Conclusion: This is the first report about conversion of major ginsenosides into minor ginsenosides by fermentation with P. grandiflorum endophytes. The results of the study indicate endophyte JG09 would be a potential microbial source for obtaining minor ginsenosides.