• Molecules and Cells
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• v.24 no.1
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• pp.113-118
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• 2007

The brains of Alzheimer's disease (AD) patients are characterized by large deposits of amyloid beta peptide ($A{\beta}$). $A{\beta}$ is known to increase free radical production in nerve cells, leading to cell death that is characterized by lipid peroxidation, free radical formation, protein oxidation, and DNA/RNA oxidation. In this study, we selected an extract of Gardenia jasminoides by screening, and investigated its ameliorating effects on $A{\beta}$-induced oxidative stress using PC12 cells. The effects of the extract were evaluated using the 2',7'-dichlorofluorescein diacetate (DCF-DA) assay and the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction assay. To find the active component, the ethanol extract was partitioned with hexane, chloroform, and ethyl acetate, respectively, and the active component was purified by silica-gel column chromatography and HPLC. The results suggested that Gardenia jasminoides extract can reduce the cytotoxicity of $A{\beta}$ in PC 12 cells, possibly by reducing oxidative stress.

• Archives of Pharmacal Research
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• v.26 no.4
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• pp.279-285
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• 2003

In our ongoing study to identity antioxidants from natural sources, the antioxidant activity of Nelumbo nucifera stamens was evaluated for their potential to scavenge stable 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radicals, inhibit total reactive oxygen species (ROS) generation, in kidney homogenates using 2 ,7 -dichlorodihydrofluorescein diacetate (DCHF-DA), and scavenge authentic peroxynitrites ($ONOO^-$). A methanol (MeOH) extract of the stamens of N. nucifera showed strong antioxidant activity in the $ONOO^-$system, and marginal activity in the DPPH and total ROS systems, so were therefore fractionated with several organic solvents, such as dichloromethane ($CH_2 Cl_2$), ethyl acetate (EtOAc) and n-butanol (n-BuOH). The EtOAc soluble fraction, which exhibited strong antioxidant activity in all the model systems tested, was further purified by repeated silica gel and Sephadex LH-20 column chromatographies. Seven known flavonoids [kaempferol (1), kaempferol 3-Ο-$\beta$-D-glucuronopyranosyl methylester (2), kaempferol 3-Ο-$\beta$-D-glucopyranoside (3), kaempferol 3-Ο-$\beta$-D-galactopyranoside (4), myricetin 3 ,5 -dimethylether 3-Ο-$\beta$-D-glucopyranoside (5), kaempferol 3-Ο-$\alpha$-L-rhamnopyranosyl-(1$\rightarrow$6)-$\beta$-D-glucopyranoside (6) and kaempferol 3-Ο-$\beta$-D-glucuronopyranoside (7)], along with $\beta$-sitosterol glucopyranoside (8), were isolated. Compound 1 possessed good activities in all the model systems tested. Compounds 2 and 7 showed scavenging activities in the DPPH and $ONOO^-$ tests, while compounds 3 and 4 were only active in the $ONOO^-$ test. Conversely, compound 8 showed no activities in any of the model systems tested.

• Fire Science and Engineering
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• v.30 no.3
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• pp.67-72
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• 2016

The development of flame retardants aims to prevent the spread of fire and reduce the casualties caused by flammable and toxic gases generated during the combustion of building materials used in the interiors of multi-use facilities. Flame material application provides flame resistance to a silica sol in an organic-inorganic hybrid material by flame retardant adhesive or coating by producing a sol-gel method. The conventional flame retardant materials, non-flame retardant material is applied with Halogen freeway. In particular, the basic physical properties of conventional adhesive coating improves the heat resistance, enhances the durability fire and heat, and expands the halogen free flame retardant of building materials.

• Journal of the Mineralogical Society of Korea
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• v.5 no.1
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• pp.6-13
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• 1992

Thermodynamic data of mineral reactions were used to construct a phase diagram for the formation of illite from andalusite at one bar and 325${\circ}C$ in the hydrothermal alteration. Based on chemical compositions, the free energy of formation of illite coexisting with andalusite was calculated by assuming the ideal mixing ina bunary system consisting of muscovite and pyrophyllite components. For illite with structural formula $K_{0.86}Al_{2.93}Si_{3.03}O_{10}(OH)_2$, its free energy of formation is -1147.727 kcal/mole at the condition under consideration. The stability area of illite is more narrow than that of end-member muscovite and prefers lower activity of silica. Illite was formed by hydration of andalusite while pyrophyllite decomposed. Illitization took place preferentially at margin and/or along fractures of andalusite.

• Journal of the Korean Wood Science and Technology
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• v.31 no.1
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• pp.32-40
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• 2003

Antimicrobial and antioxidative activities of heartwood extractives of domestic species were investigated to develop a natural fungicide or preservative. Four lignan derivatives and one taxane were isolated from heartwood of Taxus cuspidata which has been selected due to its high antioxidative activity among the tested species. The chemical structures were identified as : taxusin, isolariciresinol (4, 4', 9, 9'-tetrahydroxy-3', 5-dimethoxy-2, 7'-cyclolignan), lariciresinol (4, 4', 9-trihydroxy-3, 3'-dimethoxy-7, 9'-epoxylignan), taxiresinol (3, 4, 4', 9-tetrahydroxy-3'-methoxy-7, 9'-epoxylignan) and isotaxiresinol (3', 4, 4', 9, 9'-pentahydroxy- 5-methoxy-2, 7'-cyclolignan) on the basis of spectroscopic data and their chemical correlations. According to the results of free radical scavenging activity, isolariciresinol, lariciresinol and isotaxiresinol showed higher radical scavenging activity than those of 𝛼-tocopherol and butylated hydroxytoluene (BHT), the strongest natural and synthetic antioxidants. However, taxusin did not show any free radical scavenging activity. In this regard, it could inferred that high antioxidative activity of extractives of T. cuspidata was derived from isolariciresinol, lariciresinol and isotaxiresinol.

• Journal of the Korea Concrete Institute
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• v.19 no.5
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• pp.549-555
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• 2007

Although blast furnace slag has been widely used in concrete as a cementitious admixture or aggregate for many years, the slowly cooled steel slag is not used in concrete but mainly in road. Its use in concrete operates problem such as the lack of volume stability due to high free CaO content, which can be potentially hazardous in concrete. However, the rapidly cooled steel slag by atomization has a low free CaO content, a high density, and a spherical shape, so it is expected to use in concrete so much. This paper is to understand the probability that the rapid cooled steel slag can replace the silica sand used as aggregate in the epoxy mortar. We did the experimental study on the properties of the epoxy mortar having various replacement proportion of rapidly cooled steel slag. This study shown that increasing content of the rapidly cooled steel slag in epoxy mortar lead to increase largely the passing time of nozzle by O-lot, compressive strength and flexural strength. However except the flow is almost same level. So we understand that the rapidly cooled steel slag has positive effect on increasing of properties in epoxy mortar.

• Korean Journal of Food Science and Technology
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• v.31 no.2
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• pp.308-313
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• 1999

Total polar lipid produced from the soybean oil and lard by heating with different surface area at $185^{\circ}C$ were measured by silica gel column chromatography. Further, the polar lipid was fractionated by high performance size exclusion chromatography-evaporative light scattering detector (HPSEC-ELSD). The HPSEC system was composed of two GPC columns $(100\;{\AA}\;and\;500\;{\AA})$ and a THF mobile phase. With this system it was possible to fractionate into the free fatty acid, diglyceride, triglyceride monomer, triglyceride dimer and triglyceride polymers. The triglyceride monomer, triglyceride dimer and triglyceride polymers significantly increased as the heating time and surface area increased. But diglyceride and free fatty acid did not increased as the heating time and surface area increased. Triglyceride polymer (r>0.93), triglyceride dimer (r>0.97), triglyceride monomer (r>0.95) showed a high correlation with polar lipid content. On the other hand, diglyceride (r<0.68) and free fatty acid (r<0.76) were not significantly correlated with the polar lipid content. These results indicated that a major oxidative components formed during thermal oxidation were triglyceride polymers and triglyceride dimer and triglyceride monomer.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.746-749
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• 2004

A new-type of FRP-concrete composite bridge deck system is proposed and its behaviors are experimentally studied. The new-typedeck consists of FRP as a permanent form and main tension resisting member and concrete as a compression resisting member. A suitable bonding method such as silica coating is applied to the interface between FRP and concrete to ensure composite behavior. The proposed deck system uses the box-shape FRP member, while a typical FRP-concrete composite deck uses the I-shape FRP member. Theproposed deck system has inherent advantages of a FRP-concrete composite deck like corrosion free and easy construction. The new-type deck shows the equal performances compared to a previous one, and has the advantage of reducing self-weight. In this study, the static tests on 3-span FRP-concrete decks in full scale are carried out, so that load-displacement relation, stress distribution, failure mode and design criteria are analyzed. The test results show that the deflection design criterion (L/800, L: span length) is satisfied at the service load state. No concrete tensile crack occurs in the negative moment region above the main girder, regardless of no tensile reinforcement at upper concrete portion.

• Journal of Nutrition and Health
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• v.30 no.1
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• pp.25-31
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• 1997

The effects of Trichosanthes kirilowii Max. subfractions, which has long been used as a wild vegetable and folk medicine, on insulin activity and acute toxicity were investigated. Diabetes melitus was induced in male Sprague-Dawley rats by the injection of streptozotocin(STZ) into the tail vein at a dose of 45mg/kg. The hexane fraction of the plant was subfractioned by silica gel column chromatography and were administered orally for 14 days and the normal and STZ-control group were orally administered with tween 80. The body weight gain was monitored and plasma levels of glucose, cholesterol, triglyceride, free fatty acid HDL-cholesterol were determined. The plasma activities of aspartate aminotransferase(AST) and alanine aminotransferase (ALT) were analysed. The subjraction A of hexane fraction lowered plasma glucose levels significantly and increased insulin activity compared to that of STZ-control. The activities of AST and ALT were decreased by administration of subfractions A and C of hexane fraction. The intakes of the hexane fraction of Trichosanthes kirilowii Max. did not showed the acute toxicity. It is suggested from the results that the subfraction A of the hexane fraction of Trichosanthes kirilowii Max. showed a hypoglycemic effect on diabetic rats and that the subfraction may be beneficial for insulin secreation.

• Journal of Food Hygiene and Safety
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• v.18 no.2
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• pp.43-50
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• 2003

A liquid chromatographic method, using matrix solid-phase dispersion (MSPD) is developed for the extraction of residual furazolidone in chicken eggs. Blank or fortified egg samples (0.5 g) were blended with Octadecylsilyl (Bulk $C_{18}$, 40${\mu}{\textrm}{m}$, 18%. load, endcapped. 2 g) derivatized silica. After homogenization, $C_{18}$/egg and Na$_2$S $O_4$matrix were transferred to a column made of 10 ml glass syringe and filter paper and compressed 4.0∼4.5 ml volume. The column was washed with 8 ml of hexane and dried under $N_2$ gas. Furazolidone was eluted with acetonitrile (8 ml) under gravity. The eluate containing furazolidone was free from interfering compounds when analyzed by HPLC with UV detection (365 nm, photodiode array). Calibration curves were linear (r = 0.99985) and inter- (1.47%) and intra-assay (5.29%) variabilities for the concentration range examined (7.8∼497 ng/g of eggs, 20 ${mu}ell$ injection volume) were indicative of an acceptable methodology for the analysis of furazolidone. Average recovery of furazolidone added to egg was 96.2%. The limit of detection for the proposed method was 1 ng/g for furazolidone. The method using MSPD is proposed as an alternative assay to the classical method which involves the use of large volumes of a harmful solvent and requires a long tedious separation and clean-up processes prior to its determination.