• 한국응용과학기술학회지
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• 제9권2호
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• pp.157-163
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• 1992

A microorganism, isolated from soil and designated Pseudomonas sp13, produced two kinds of rhamnolipid in the medium containing glucose as carbon source. There were both rhamnolipid contain L-rhamnose and ${\beta}$-hydroxydecanoic acid. Coumpound A and B elucted chloroform-methanol mixed solution of silicic acid column chromatography and recrystallized from a mixture of ether and n-hexane. Studies on the structure of these products reveled that compound A is L-rhamnopyranosyl-${\beta}$-hydroxydecanoyl-${\beta}$-hydroxydecanoic acid and compound B is L-rhamnopyranosyl-L-rhamnopyranosyl-${\beta}$-hydroxydecanoyl-${\beta}$-hydroxydecanoic acid.

• 에너지공학
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• 제14권1호
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• pp.18-23
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• 2005

본 연구는 저온축열물질로서 TMA(Tri-methyl-amine, (CH₃)₃N)를 20～25 wt％로 포함하고 있는 TMA-물계 포접화합물의 냉각특성에 대하여 냉열원온도 -5℃에서 실험적으로 연구를 수행하였다. 연구결과, TMA의 질량농도가 증가할수록 상변화온도와 비열이 증가하였으며, 과냉도가 감소하고 액상유지시간이 단축되었다 특히, TMA 25wt%를 포함한 TMA-물계 포접화합물은 상변화온도 평균 5.8℃, 과냉도 8.0℃, 액상유지시간 10분, 비열 4.099kJ/kg℃를 나타내었다. 본 연구의 결과로부터 TMA-물계 포접화합물은 물보다 높은 상변화온도를 나타내었으며, 과냉도가 감소하고, 액상유지시간이 단축되는 과냉각 억제효과를 확인 할 수 있었다.

• Journal of Korean Neurosurgical Society
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• 제65권1호
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• pp.4-12
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• 2022

Objective : We reported the differentially methylated genes in patients with subarachnoid hemorrhage (SAH) using bioinformatics analyses to explore the biological characteristics of the development of delayed cerebral ischemia (DCI). Methods : DNA methylation profiles obtained from 40 SAH patients from an epigenome-wide association study were analyzed. Functional enrichment analysis, protein-protein interaction (PPI) network, and module analyses were carried out. Results : A total of 13 patients (32.5%) experienced DCI during the follow-up. In total, we categorized the genes into the two groups of hypermethylation (n=910) and hypomethylation (n=870). The hypermethylated genes referred to biological processes of organic cyclic compound biosynthesis, nucleobase-containing compound biosynthesis, heterocycle biosynthesis, aromatic compound biosynthesis and cellular nitrogen compound biosynthesis. The hypomethylated genes referred to biological processes of carbohydrate metabolism, the regulation of cell size, and the detection of a stimulus, and molecular functions of amylase activity, and hydrolase activity. Based on PPI network and module analysis, three hypermethylation modules were mainly associated with antigen-processing, Golgi-to-ER retrograde transport, and G alpha (i) signaling events, and two hypomethylation modules were associated with post-translational protein phosphorylation and the regulation of natural killer cell chemotaxis. VHL, KIF3A, KIFAP3, RACGAP1, and OPRM1 were identified as hub genes for hypermethylation, and ALB and IL5 as hub genes for hypomethylation. Conclusion : This study provided novel insights into DCI pathogenesis following SAH. Differently methylated hub genes can be useful biomarkers for the accurate DCI diagnosis.

• 열처리공학회지
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• 제8권4호
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• pp.279-288
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• 1995

To investigate the characteristics of nitrocarburizing for high carbon chromium bearing steel, it was undertaken 4 hours holding at $850^{\circ}C$ in the atmosphere containing 60% endothermic gas and 40% ammonia. The microstructure of nitrocarburized surface consists of ${\varepsilon}-Fe_{2-3}N$, ${\gamma}^{\prime}-Fe_4N$, $Fe_3C$ and $Fe_3$(C,N), and the ${\varepsilon}$-nitride was rich in the surface-internal part. The nitrocarburized surface contains a larger volume fraction of primary carbonitrides and has more retained austenite and is slightly harder than the interior.

• Bulletin of the Korean Chemical Society
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• 제12권5호
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• pp.583-588
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• 1991

A series of dimesogenic compounds having two identical, terminal Schiff base type mesogens and a central polymethylene spacer were prepared and their properties were compared with those of the corresponding monomesogenic compounds. The mesomorphic properties of the compounds were studied by differential scanning calorimetry and on a hot-stage of a polarizing microscope. All of the dimesogenic compounds formed mesophases enantiotropically with the exception of pentamethylene-1,5-bis(4-oxybenzylidene 4-n-butylaniline). This compound was monotropic and formed only a nematic phase on heating the solid, whereas it formed nematic as well as smectic A phases on cooling the isotropic liquid. Those compounds containing longer (octamethylene and decamethylene) spacers favored the formation of nematic phase whereas those having shorter (dimethylene and tetramethylene) spacers formed smectic phases. In general, the variety of mesophase forms exhibited by the dimesogenic compounds was significantly less than that shown by the corresponding monomesogenic compounds.

• Rapid Communication in Photoscience
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• 제1권1호
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• pp.19-20
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• 2012

Novel star-shaped imide compounds containing electron-donating triphenylamine and/or electron-withdrawing bis(trifluoromethyl)phenyl side groups were synthesized via a two-step process. First, 3,6-dibromo-benzene-1,2,4,5-tetracarboxylic acid (2B4BA) was reacted with 4-aminophenyl (diphenylamine) (ATPA) or 3,5-bis(trifluoromethyl)aniline (6FA) by imide reaction. Then, Suzuki coupling reaction was carried out on these compounds with 4-(N,N-diphenylamino)-1-phenyl boronic acid (BTPA) or 3,5-bis(trifluoromethyl)phenyl boronic acid (6FBB), resulting in 3,6-bis[4-(diphenylamino)phenyl]-N,N'-bis[4-(diphenylamino) phenyl]-pyromellitimide (TPTPPI), 3,6-bis[3,5-bis(trifluoro methyl) phenyl]-N,N'-bis[3,5-bis(trifluoromethyl) phenyl]-pyro mellitimide (6F6FPI) or 3,6-bis[4-(diphenylamino)phenyl]-N,N'-bis[3,5-bistrifluoromethyl)phenyl]-pyromellitimide (6FTPPI). The imide compounds obtained were characterized by NMR, FT-IR, DSC, TGA, melting point analyzer, EA, and solubility measurements. In addition, their optical and electrical properties were evaluated by fluorescence spectroscopy, UV-vis spectroscopy, and cyclic voltammetry (CV). 6F6FPI exhibited deep blue emission (443 nm), along with high $T_m$ ($382^{\circ}C$) and relatively high $T_g$ ($148^{\circ}C$).

• 한국식생활문화학회지
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• 제34권1호
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• pp.53-60
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• 2019

This study investigated the sensory characteristics and antioxidative activity of the reduced salt dried bulgogi bibimbap containing AF-343, a dandelion-derived compound extract. A sample with a 30% reduced salt had a sodium amount of 659.01 mg, which was significantly lower than that of the sample before the reduction (p<0.05). The textural hardness of the SW (Standard sample with the AF-343), showed the lowest value of $1.03N/cm^2$, indicating that the AF-343-containing sample could have a slightly softer texture than the non-containing sample. In the analytical sensory test, the AF-343-containing samples showed a synergistic effect on the aroma and flavor of bulgogi, with values of 5.7 and 8.4, respectively, which were significantly higher than that of the non-containing sample group (4.3 and 4.4, respectively). The hardness by the sensory test was slightly hard with values of 7.2-8.1 in all samples, indicating that textural improvement was needed. In the acceptance test, all the samples scored with slightly lower values of 4-5 points, highlighting the need for future studies to improve the sensory characteristics of dried bibimbap. The flavonoid contents of AF-343-containing SW and RW sample groups were 68.21 and 64.31 mg GAE/100 g, respectively, which were significantly higher than those of the samples without AF-343 (49.06 and 44.82 mg GAE/100 g, respectively) (p<0.05). The ABTS and DPPH radical scavenging activities were similar to those of the flavonoid contents. As a result, in the production of AF-343-containing reduced-salt dried bulgogi bibimbap, more study on the textural improvement will be needed to achieve better palatability.

• Bulletin of the Korean Chemical Society
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• 제32권5호
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• pp.1613-1619
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• 2011

A hybrid thermosetting maleimido epoxy compound 4-(N-maleimidophenyl) glycidylether (N-MPGE) containing Co(II), Ni(II) and Cu(II) ions was prepared by curing N-MPGE and tetradentate Schiff base Co(II), Ni(II) and Cu(II) complexes. The curing polymerization reaction of N-MPGE with metal complexes as curing agents was studied. The cured samples were studied for thermal stability, chemical (acid/alkali/solvent) and water absorption resistance and homogeneity of the cured systems. The tetradentate Schiff base, 3-[(Z)-2-piperazin-1-yl-ethylimino]-1,3-dihydro indol-2-one was synthesized by the condensation of Isatin (Indole-2, 3-dione) with 1-(2-aminoethyl)piperazine (AEP). Its complexes with Co(II), Ni(II) and Cu(II) have been synthesized and characterized by microanalysis, conductivity, Uv-Visible, FT-IR, TGA and magnetic susceptibility measurements. The spectral data revealed that the ligand acts as a neutral tetradentate Schiff base and coordinating through the azomethine nitrogen, two piperazine nitrogen atoms and carbonyl oxygen.

• 한국환경농학회지
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• 제19권2호
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• pp.183-187
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• 2000

고농도 축산폐수의 과부하 고도처리를 위한 토양미생물을 이용한 공정개발 연구결과 질소${\cdot}$제거율은 97% 이었다. 질산화를 위한 최소 HRT는 11일 이었으며 이때의 SRT는 25일 이었다. HRT 5일에서 11일 사이에 도 질산화는 있었으나 이 때는 $NO_2-N$이 대부분으로 완전질산화를 달성하지는 못했다. pH와 $NO_2\;^--N$, $NH_3\;^--N$ 의 관계로부터 반응조는 nitrosomonas 저해영역에 속해 있었으나 약간의 pH 조절로 충분한 질산화를 달성할 수 있을 것으로 판단되었다.

• Journal of Ginseng Research
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• 제22권4호
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• pp.274-283
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• 1998

It has generally been accepted that quality of ginseng should be determined not by the content of a single component but by composition and balance of total active principles. However, there still can be an exception with a product in which a given ginsenoside is used for the treatment of a specific disease. Although ginsenosides have been regarded to be major active components of ginseng and employed as index components for the quality control, it does not consistent with the traditional concept on ginseng quality creterion; main root has been more highly appreciated than the lateral or fine root. Content of ginsenosides in the lateral or fine root is much higher than that in main root. However, the ratio of protopanaxadiol (PD) and protopanaxatriol (PT) saponins existing in various part of ginseng root is greatly different. The ratio of PD/PT saponins in main root is well balanced but the thinner the root is the higher the ratio. Thus far, a total of 34 different kinds of ginsenosides have been isolated from Korean (red) ginseng, and their pharmacological activities were elucidated partly. Interestingly, different ginsenoside shows similar or contrary effects to each other in biological systems, thus indicating the significance of absolute content of single ginsenoside as well as compositional patterns of each ginsenoside. Therefore, pharmacological activities of ginseng should be determined as a wholly concept. In these regards, standardization of ginseng material (fresh ginseng root) should be preceded to the standardization of ginseng products because ginsenoside content and non-saponin active principles such as polysaccharides and nitrogen (N)-containing compound including proteins are significantly different from part to part of the root. In other words, the main root contains less ginsenosides than other lateral or fine roots. Contents of polysaccharides and N-containing compound in main root is higher. However, the quality control of ginseng products focused on non-saponin compounds has limitation in applying to the analytical method, because of the difficult chemical analysis of these compounds. Content of ginsenosides, and ratios of PD/PT and ginsenoside Rb,/Rg, are inversely proportional to the diameter of ginseng root. Therefore, these can be served as the chemical parameters for the indirect method of evaluating from what part of the root does the material originate. Furthermore, contents of polysaccharides and N-containing compounds show inverse relationship to saponin content. Therefore, it seems that index for analytical chemistry of saponin can be applied to the indirect method of evaluating not only saponin but also non-saponin compounds of ginseng. From these viewpoints, it is strongly recommended that quality of ginseng or ginseng products be judged not only by the absolute content of given ginsenoside but also by varieties and compositional balance of ginsenosides, including contents of non-saponin active principles.