• Bulletin of the Korean Chemical Society
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• v.33 no.6
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• pp.1955-1961
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• 2012

In this work, the reactions of carbamyl and thiocarbamyl halides with $NH_3$ were studied in the gas phase at the MP2(FC)/6-31+G(d) level of theory. Single point calculations were performed at the QCISD/6-311+G(3df,2p) to refine the energetics. The reaction mechanisms were also studied in aqueous solution. The structures were fully optimized at the CPCM-MP2(FC)/6-31+G(d) and refined by a single point CPCM-QCISD/6-311+G(3df,2p) calculations. The reaction mechanisms for the title compounds were compared with those for the acetyl and thioacetyl halides. The lower reactivity of carbamyl (and thiocarbamyl) groups was explained by comparing the C=O and C=S ${\pi}$-bond strengths as well as resonance contributions in the ground state.

• Journal of Integrative Natural Science
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• v.6 no.1
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• pp.8-11
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• 2013

In this manuscript, we report a protocol to determine most of the lowest energy conformations from the ensemble of conformations. 12-crown-4 was taken as study compound to get the most of energy minima conformations. Molecular dynamic (MD) simulation for 1 nanosecond (ns) was performed at 300, 500, 700, 900 and 1100 K temperature. At particular interval conformations were sampled. Then Gaussian program was used to minimize compounds using PM6 energy levels. Duplicates were removed by checking energy as well as mirror image conformations, and only unique conformations were retained for the next $6-31+G^*$ level minimization. It was observed that upto certain increment in temperature the number of unique conformations were increased, but afterword it decreased.

• Bulletin of the Korean Chemical Society
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• v.31 no.9
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• pp.2509-2513
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• 2010

In order to increase protease stability of a novel Trp-rich model antimicrobial peptide, $K_6L_2W_3$ (KLWKKWKKWLK-$NH_2$)and investigate the effect of L-amino acid to peptoid residue conversion on biological functions, we synthesized its antimicrobial peptoid, $k_6l_2w_3$. Peptoid $k_6l_2w_3$ had similar bacterial selectivity compared to peptide $k_66L_2W_3$. The bactericidal rate of $k_6l_2w_3$ was somewhat slower than that of $K_6L_2W_3$. Peptoid $k_6l_2w_3$ exhibited very little dye leakage from bacterial outer-membrane mimicking PE/PG liposomes, as observed in $K_6L_2W_3$, indicating that the major target site of $K_6L_2W_3$ and $k_6l_2w_3$ may be not the cell membrane but the cytoplasm of bacteria. Trypsin treatment of $K_6L_2W_3$ completely abolished antimicrobial activities against Escherichia coli and Staphylococcus aureus. In contrast, the antimicrobial activity of $k_6l_2w_3$ was completely preserved after trypsin treatment. Taken together, our results suggested that antimicrobial peptoid $k_6l_2w_3$ can potentially serves as a promising therapeutic agent for the treatment of microbial infection.

• Reproductive and Developmental Biology
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• v.32 no.4
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• pp.223-227
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• 2008

Human embryonic stem (ES) cells retain the capacity for self-renewal, are pluripotent and differentiate into the three embryonic germ layer cells. The regulatory transcription factors Oct4, Nanog and Sox2 play an important role in maintaining the pluripotency of human ES cells. The aim of this research was to identify unknown genes upregulated in human ES cells along with Oct4, Nanog, and Sox2. This study characterizes an unknown gene, named chromosome 1 open reading frame 31 (C1orf31) mapping to chromosome 1q42.2. The product of C1orf31 is the hypothetical protein LOC388753 having a cytochrome c oxidase subunit VIb (COX6b) motif. In order to compare expression levels of C1orf31 in human ES cells, human embryoid body cells, vascular angiogenic progenitor cells (VAPCs), cord-blood endothelial progenitor cells (CB-EPCs) and somatic cell lines, we performed RT-PCR analysis. Interestingly, C1orf31 was highly expressed in human ES cells, cancer cell lines and SV40-immortalized cells. It has a similar expression pattern to the Oct4 gene in human ES cells and cancer cells. Also, the expression level of C1orf31 was shown to be upregulated in the S phase and early G2 phase of synchronized HeLa cells, leading us to purpose that it may be involved in the S/G2 transition process. For these reasons, we assume that C1orf31 may play a role in on differentiation of human ES cells and carcinogenesis.

• Journal of Life Science
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• v.10 no.2
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• pp.12-13
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• 2000

A human-specific retroposon SINE-R.C2 has been derived from a human endogenous retrovirus HER V-K 10. It is absent in the genome of nonhuman primates and present within the third intron of the human C2 gene that is located in the class III region of the major histocompatibility complex. In the present study, we determined the regional location of the human C2 gene. The analysis of the Genebridge 4 radiation hybrid mapping panel using PCR amplification located the C2 gene between D6S1422 (10.1 cR) and CHLC.GATA4A03 (21.3) with a lod score of>3.0. This allowed us to localize C2 gene on the human chromosome 6 band p21.31.

• Journal of the Korean Institute of Landscape Architecture
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• v.31 no.6
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• pp.77-84
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• 2004

This study was carried out to analyze the vertical and horizontal distribution of fine root biomass of Pinus thunbergii transplanted in reclaimed land from the sea near Gwangyang Bay. The fine-root biomass according to 6 planting ground types were as follows: 98.5 g DM/$m^2$ for P2, 51.1 g DM/$m^2$ for P6, 47.8 g DM$m^2$ for P5, 44.6 g DM/$m^2$ for P3, 38.2 g DM/$m^2$ for P4, 31.8 g DM/$m^2$ for Pl, respectively. The vertical distribution of fine root biomass decreased at descending soil depths of the 6 mounding types. Fine root biomass was 31∼55% in the topsoil of 20cm depth. Fine root biomass that were related to the Spatial distance from the nearest tree were unevenly distributed horizontally in 6 stands. distribution patterns of fine root biomass were closely related to soil hardness and alkalic cation (Ca++, Mg++, Na+, K+) concentrations. Therefore, in order to have good condition for the growth of landscaping plants, we suggest that there is a need for the construction of planting grounds as well as a need for soil improvement in bad soil environments.

• Bulletin of the Korean Chemical Society
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• v.31 no.6
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• pp.1628-1632
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• 2010

Porous ${\eta}-Al_2O_3$ was synthesized by modified sol-gel method using ionic liquid as a templating material. The addition of ionic liquid assisted to increase the surface area of alumina. However, the acidity of aluminas prepared with ionic liquids was hardly affected regardless the change of its structural properties. Among the ionic liquids used in this study, 1-butyl-3-methylimidazolium hexafluorophosphate ([Bmim][$PF_6$]) was the most effective ionic liquid to produce porous ${\eta}-Al_2O_3$ particles. The catalytic performance of these aluminas has been investigated in dehydration of methanol to produce dimethyl ether. The alumina prepared with [Bmim][$PF_6$] outperformed the other aluminas except ${\eta}-Al_2O_3$ without modification in this reaction.

• The Bulletin of The Korean Astronomical Society
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• v.39 no.1
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• pp.41.2-41.2
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• 2014

Hierarchical merging scenario indicates that galaxies go through major and minor merger events during their formation and evolution. As a result of the merging, substructural features of remnants such as stellar stream are shown around a current galaxy system. To find evidence of stellar substructures on M31 system, we used the near-infrared images of JHK filters obtained from the Wide Field Camera (WFCAM) at UKIRT 3.8m. A total sky coverage is an area of about$ 4.5^{\circ}{\times}6^{\circ}$ around M31. Indeed, M31 system which consists of several satellite systems contains stellar substructures such as giant stellar stream, loops, and spurs. By analysing stellar populations on the near-infrared color-magnitude diagrams, we selected member star candidates of each stellar substructure, from which we map out spatial distribution of stars in the vicinity of M31 system. Here, we present spatial density distribution maps of stars on each substructure over the entire field of M31 system. Also, we discuss the possible origin of the substructures and the implications on the galaxy assembly process.

• Bulletin of the Korean Chemical Society
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• v.31 no.5
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• pp.1415-1418
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• 2010

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.05a
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• pp.80-83
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• 2004

High temperature deformation behavior of AZ31 Mg alloy was investigated in this study on the basis of a processing map $(\varepsilon\approx0.6)$. To construct a processing map, compression tests were carried out at wide range of temperatures and strain rates $(T=250\~500^{\circ}C,\;\varepsilon=10^{-4}\~100/s)$. Two regions of high deformation efficiency $(\eta)$ were identified as: (1) a dynamic recrystalization (DRX) domain at $250^{\circ}C$ and 1/s and (2) a superplasticity domain at $450^{\circ}C$ and $10^{-4}/s$. Possible deformation mechanisms operating at high temperature were discussed in relation to the activation energy. A two-stage deformation method was found to be effective in enhancing the superplasticity of AZ31 Mg alloy. From the two-stage deformation method, tensile elongation of $1200\%$ was obtained at the superplastic domain.