• Journal of the Mineralogical Society of Korea
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• v.28 no.1
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• pp.51-60
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• 2015

We applied gemological analytical approaches on Aquamarine from the Gilgit-Baltistan of Northern Areas, Pakistan. The standard gemological testing indicates that they are consistent with general characteristics of natural aquamarines. We have identified the inclusions of Tantalite-Mn by Raman analysis. It indicates that they occurs in association with the veins of Be-rich coarse pegmatite. And the results of chemical analyses, infrared absorption spectroscopy and Raman spectroscopy indicate that $H_2O$ molecules in channel mostly exist in Type-I and a little Type-II with low alkali ion. The comparison of relative peak intensity of FT-IR analysis can be used for prediction of $Na_2O$ content within not only emerald but also aquamarine.

• Bulletin of the Korean Chemical Society
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• v.33 no.12
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• pp.4028-4034
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• 2012

Tris(2-phenylphenoxo)aluminum ($(2-PhC_6H_4O)_3Al$) exists as a dimeric form in toluene. When toluene-insoluble anhydrous cobalt acetate is treated with tris(2-phenylphenoxo)aluminum in toluene, the toluene-soluble adduct $(2-PhC_6H_4O)_3Al{\cdot}Co(OAc)_2$ is formed. The 2-phenylphenoxo ligand in the adduct can be replaced with another aryloxo ligand to give (aryloxo)$(2-PhC_6H_4O)_2Al{\cdot}Co(OAc)_2$ (aryloxo = 2-methylphenoxo, 2-isopropylphenoxo, 4-methylphenoxo, 4-isopropylphenoxo, or 4-tert-butylphenoxo). These complexes are active for butadiene polymerization without gel formation when activated with an equivalent amount of $(2-PhC_6H_4O)AlEt_2$ for 2 h. The highest activity, 175 kg/mol-Co (turnover number, 3200) was achieved with $(2-PhC_6H_4O)_3Al{\cdot}Co(OAc)_2$ at $65^{\circ}C$ for 2 h. The microstructure of the polymer chains is mostly trans-1,4-configuration (70-75%) with the remaining being 1,2-vinyl. The cis-1,4-configuration observed by IR is minimal (1-5%). By replacing the 2-phenylpheoxo with a 4-alkylphenoxo ligand, the amount of 1,4-configuration slightly increases, resulting in increase in the endothermic melting signal at $-30{\sim}50^{\circ}C$ in the DSC curve. The molecular weights of the polymers are high ($M_n$: 300000~800000) with a fairly narrow molecular weight distribution ($M_w/M_n$, 2.0-2.7).

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.19 no.3
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• pp.261-269
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• 2009

To evaluate the effect of antioxidant on the cytotoxicity induced by oxidative stress of reactive oxygen species (ROS) in cultured human skin melanocytes, colorimeric assay of XTT and tyrosinase activity assay were adopted after human skin melanocytes were preincubated for 2 hours in the media containing various concentrations of superoxide dismutase (SOD) before the treatment of hydrogen peroxide. Light microscopic study was carried out in same cultures. The results of this study were as follows 1. Cell viability of human skin melanocytes was significantly decreased by 30 and $40{\mu}M$ of hydrogen peroxide($H_2O_2$), respectively. 2. XTT50 was determined at $30{\mu}M$ after human skin melanocytes were treated with $10{\sim}40{\mu}M$ of hydrogen peroxide for 6 hours. 3. The cell viability of cultured human skin melanocytes pretreated with SOD was increased than that of cultured human skin melanocytes treated with $H_2O_2$ dose-dependently. 4. In tyrosinase activity of human skin melanocytes, the cell treated with SOD showed brown stain compared with $H_2O_2$ treated cells, dark stain. 5. In light microscopy, cultured human skin melanocytes exposed to $H_2O_2$ showed morphological changes such as the decreased cell number and cytoplasmic processes, compared with control. 6. In light microscopy, cultured human skin melanocytes pretreated with SOD showed the increase of cell number and cytoplasmic processes compared with $H_2O_2-treated$ group. From these results, it is suggested that oxidative stress of ROS such as $H_2O_2$ has cytotoxicity by showing the decreased cell viability, the increased tyrosinase activity and mophological changes of the decreased cell number and cytoplasmic processes. While, antioxidant like SOD was effective in the prevention of oxidative stress-mediated cytotoxicity by the increased cell viability, decreased tyrosinase activity and the protection of degenerative morphological changes in cultured human skin melanocytes.

• Korean Journal of Acupuncture
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• v.22 no.2
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• pp.43-56
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• 2005

Objective : This study was produced to examine the effects of moxibustion that had been played important role to traditional oriental medical treatment on disease. Recently, it was reported that moxi-tar which is generated in the process of moxibustion as burning combustibles decreased NO and iNOS generation in $C_6-glioma$ and RAW 264.7 cells in our lab. The purpose of this research was to investigate the protect reaction on cell injury induced by the $H_2O_2$ in $C_6-glioma$ cells. Methods : $C_6-glioma$ cells were cultured in RPMI 1640 with FBS 10% in $CO_2$ incubator. To study the protective effects of moxi-tar, we observed cell viability, DPPH activity, SOD activity, catalase activity and cell morphology after injury with $H_2O_2$. Results : Moxi-tar increased cell viability about twice as much as that of being injury by $H_2O_2$(moxi-tar $40\;{\mu}g/m{\ell}$, $H_2O_2\;500\;{\mu}\;M$). And the results of free radical scavenger activity ($80\;{\mu}g/\;m{\ell}\;:\;78.91\;{\pm}\; 4.4%$), SOD activity and catalase activity ($80\;{\mu}g/\;m{\ell}$: 21.6 unit/ mg protein) were increased by moxi- tar as dose-dependent manner. Conclusion: we concluded that the effects of moxibustion which is played important role in Oriental medicine, might be free radical scavenger effects induced by moxi-tar.

• Molecules and Cells
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• v.26 no.1
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• pp.74-80
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• 2008

Bisphenol A bis (2,3-dihydroxypropyl) ether ($BADGE.2H_2O$) is a component of commercial liquid epoxy resins commonly used in the food-packing industry and in dental sealants. There is evidence that it has significant estrogenic activity. Nur77 plays a crucial role in the regulation of certain genes involved in LH-mediated steroidogenesis in testicular Leydig cells. It was previously demonstrated that Bisphenol A (BPA) stimulates Nur77 gene induction and steroidogenesis. In this study, we investigated the effects of $BADGE.2H_2O$ on Nur77 gene expression and steroidogenesis. Northern blot analysis showed that it increased the expression of Nur77 mRNA and protein, and transient transfection assays demonstrated that it increased the promoter activity and transactivation of Nur77. It also increased the expression of certain steroidogenic genes, such as StAR and $3{\beta}$-HSD. Finally, over-expression of a dominant negative Nur77 cDNA via adenoviral infection reduced $BADGE.2H_2O$-mediated progesterone biosynthesis. These results indicate that $BADGE.2H_2O$ disrupts testicular steroidogenesis by increasing Nur77 gene expression.

• Korean Chemical Engineering Research
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• v.44 no.2
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• pp.121-128
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• 2006

Propylene epoxidation by $H_2O_2$ (30％ aqueous) as oxidant was studied in a semi-batch reactor using TS-1 catalyst: Effects of reaction temperature, time, pressure, solvent, catalyst and $H_2O_2$ concentration on $H_2O_2$ conversion (limiting reagent) and product distribution were investigated. Potential inhibition by propylene oxide on the epoxidation rate was also examined. Ti-MCM-22 with MWW zeolytic structure was found to exhibit better performance than TS-1 with MFI structure, provide that a proper choice of solvent(acetonitrile) is made.

• Nutrition Research and Practice
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• v.13 no.4
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• pp.279-285
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• 2019

BACKGROUND/OBJECTIVES: Excessive production of reactive oxygen species (ROS) such as hydroxyl (${\cdot}OH$), nitric oxide (NO), and hydrogen peroxide ($H_2O_2$) is reported to induce oxidative stress. ROS generated by oxidative stress can potentially damage glial cells in the nervous system. Cordyceps militaris (CM), a kind of natural herb widely found in East Asia. In this study, we investigated the free radical scavenging activity of the CM extract and its neuroprotective effects in $H_2O_2$-induced C6 glial cells. MATERIALS/METHODS: The ethanol extract of CM ($100-1,000{\mu}g/mL$) was used to measure DPPH, ${\cdot}OH$, and NO radical scavenging activities. In addition, hydrogen peroxide ($H_2O_2$)-induced C6 glial cells were treated with CM at $0.5-2.5{\mu}g/mL$ for measurement of cell viability, ROS production, and protein expression resulting from oxidative stress. RESULTS: The CM extract showed high scavenging activities against DPPH, ${\cdot}OH$, and NO radicals at concentration of $1,000{\mu}g/mL$. Treatment of CM with $H_2O_2$-induced oxidative stress in C6 glial cells significantly increased cell viability, and decreased ROS production. Cyclooxygenase-2 and inducible nitric oxide synthase protein expression was down-regulated in CM-treated groups. In addition, the protein expression level of phospho-p38 mitogen-activated protein kinase (p-p38 MAPK), phospho-c-Jun N-terminal kinase (p-JNK), and phospho-extracellular regulated protein kinases (p-ERK) in $H_2O_2$-induced C6 glial cells was down-regulated upon CM administration. CONCLUSION: CM exhibited radical scavenging activity and protective effect against $H_2O_2$ as indicated by the increased cell viability, decreased ROS production, down-regulation of inflammation-related proteins as well as p-p38, p-JNK, and p-ERK protein levels. Therefore, we suggest that CM could play the protective role from oxidative stress in glial cells.

• Progress in Superconductivity
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• v.6 no.1
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• pp.37-40
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• 2004

We investigated the effects of impurity doping on the electrical transport and magnetic properties of TEX>$(Ru, Sn)(Sr, La)<_2$$EuCeCu_2$$O_{z}$ samples. We found that Sn substitution fur Ru causes a significant decrease of the volume fraction of ferromagnetic phase, as well as a decrease of the temperature where the ferromagnetic component is observed. La substitution for Sr leads to an increase of the magnetic ordering temperature with a moderate change of ferromagnetic component. The experimental results are discussed in conjunction with the structural data, transport properties and a possible change of oxygen content.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2003.11b
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• pp.41-44
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• 2003

UV/$TiO_2$ 공정을 이용한 수중 MTBE의 광분해에 관한 연구 결과 다음과 같은 결론을 얻을 수 있었다. MTBE는 초기농도가 낮을수록 제거효율이 증가하는 것을 볼 수 있었으며, 공기주입량이 4L/min인 경우 반응시간 160분 후 완전히 제거되었으며, 공기주입이 없는 경우에 비해 제거효율이 40%정도 높게 나타났다. 과산화수소 농도와 반응시간에 따른 MTBE 제거효율은 1M-$H_2O_2$ 300mL를 첨가한 경우 반응시간 160분 후에 완전히 제거되었으며, 1M-$H_2O_2$ 200m1는 반응시간 180분 후 거의 제거되었으며 $H_2O_2$를 첨가하지 않은 경우 반응시간 180분 후 68%의 제거효율을 보여 과산화수소 첨가시 제거효율이 증가하는 경향을 보였다.

• Investigative Magnetic Resonance Imaging
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• v.10 no.1
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• pp.20-25
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• 2006

Purpose : To evaluate the NMR relaxation properties of newly developed high performance paramagnetic complexes. Materials and methods : 4-aminomethylcyclohexane carboxylic acid (0.63g, 4 mmol) was mixed with the suspension solution of DMF (15mL) and DTPA-bis-anhydride (0.71g, 2 mmol) to synthesize the ligand. The ligand was then mixed with Gd2O3 (0.18g, 0.5 mmol) to synthesize Gd-chelate. For the measurement of magnetic relaxivity of paramagnetic compounds, the compounds were diluted to 1mM and then the relaxation times were measured at 1.5T(64 MHz). Inversion-recovery pulse sequence was employed for T1 relaxation measurement and CPMG(Carr-Purcell-Meiboon-Gill) pulse sequence was employed for T2 relaxation measurement. Using MATLAB(Version 7.1) program, T1 magnetic relaxation map, R1 map, T2 magnetic relaxation map and R2 map were developed to represent magnetic relaxation time and magnetic relaxivity as image. Results : Compared to $R1=4.9mM^{-1}sec^{-1}$ and $R2=4.8mM^{-1}sec^{-1}$ of Omniscan (Gadodiamide), which is commercially available paramagnetic MR agent, R1 of SUK090(Gd-C32H74N5O24) was $12.46mM^{-1}sec^{-1}$ and R1 of SUK091(Gd-C34H78N5O24) was $12.77mM^{-1}sec^{-1}$. However, R1 of SUK092(Gd-C30H56N5O17) was decreased to $2.09mM^{-1}sec^{-1}$. In case of R2, SUK090(Gd-C32H74N5O24) was $8.76mM^{-1}sec^{-1}$ and SUK091(Gd-C34H78N5O24) was $7.60mM^{-}1sec^{-1}$ whereas SUK092(Gd-C30H56N5O17) was decreased to $1.82mM^{-1}sec^{-1}$. Conclusion : Among three new paramagnetic complexes, SUK090(Gd-C32H74N5O24) and SUK091(Gd-C34H78N5O24) showed higher T1, T2 magnetic relaxation rates than that of commercially available paramagnetic MR agent and thus expected to have more contrast enhancement effect.