• Journal of the Korean Wood Science and Technology
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• v.27 no.1
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• pp.72-78
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• 1999

To accelerate the curing and to improve the bonding properties of urea-melamine-formaldehyde (UMF) resin adhesives for plywood, the effects of resin compositions and additives on gelation time and bonding strength were discussed. The gelation time of UMF resin prepared by simultaneous reaction with urea(U), melamine(M) and formaldehyde(F) at M/U molar ratio 0.2 was shortened as the molar ratio of formaldehyde to urea was increased. However, at F/U molar ratios higher than 2.5, the amounts of free fomaldehyde of resin could not satisfy with KS standard, Therefore, it was difficult to increase the amount of formaldehyde in resin composition for the purpose of fast gelation time. With increasing the molar ratio of melamine to urea(M/U) from 0.3 to 0.6 at constant F/U molar ratio 3.4, the gelation time of UMF resin was slightly decreased, while gradually increased at M/U molar ratio higher than 0.6. The gelation properties of UMF resin and bonding strength of UMF-bonded plywood could be enhanced by using ammonium chloride and p-toluene sulfonic acid as a curing-agent together with wheat flour and corngluten powder as a extender.

• Journal of Physiology & Pathology in Korean Medicine
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• v.19 no.6
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• pp.1573-1579
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• 2005

This study was undertaken to define the effect of DaeSiHo-Tang extract on the hypertension in spontaneous hypertensive rat and norepinephrine-induced arterial contraction in rabbit. Systolic blood pressure and blood velocity were significantly attenuated by administration of DaeSiHo-Tang extract. but blood flow and renin-angiotensin-aldosterone system unaffected by DaeSiHo-Tang extract. The relaxation effect of DaeSiHo-Tang extract was dependent on the presence of endothelium, showing that DaeSiHo-Tang extract-induced relaxation was not observed in the strips without endothelium. The endothelium-dependent relaxation induced by DaeSiHo-Tang extract was decreased by the pretreatment of $N{\omega}$-nitro-L-arginine or methylene blue, but it was not observed in the strips pretreated with indomethacin or tetraethylammonium chloride. When $Ca^{2+}$ was applied, the strips which were contracted by norepinephrine in a $Ca^{2+}$-free solution, arterial contraction was increased. But pre-treatment of DaeSiHo-Tang extract inhibited contractile response to $Ca^{2+}$. These results indicate that antihypertensive effect of DaeSiHo-Tang extract is due to descend arterial resistance by the arterial relaxation through the formation of nitric oxide in the vascular endothelial cells.

• Journal of the Korean Society of Food Culture
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• v.9 no.2
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• pp.131-136
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• 1994

The ethylacetate extract of Lactuca dentata Makino showed 6 flavonoidal components as detected by ferric chloride solution. The flavonoidal constituent of Lactuca dentata Makino was isolated and purified by the series of column chromatography. The chemical structure of one of the flavonoidal component named as compound E was identified by UV, IR and NMR spectrometry. The melting point range of compound E was $249.5^{\circ}C-251^{\circ}C$. The UV and IR spectra of purified compound E, and its genin were measured with the various shifting agents. The results of UV analysis showed the free state of hydroxy group at 3rd and 4th carbon and binding of sugar at the 7th carbon of compound. The sugar bound to the compound E was identified as glucose by TLC. The IR spectrum showed the presense of hydroxy group, conjugated carbonyl group and aromatic group. The analysis of NMR spectrum was done to the purified compound and its derivatives. The chemical shifts against hydrogen atom, hydroxy group, and the moiety of luteolin were observed in the NMR spectrum along with their position and number as well as type of sugar bound. The isolated and purified compound was identified as $luteolin-7-0-{\beta}-D-glucoside$.

• Korean Journal of Environmental Biology
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• v.26 no.2
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• pp.109-114
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• 2008

To evaluate the extent of Sea-Nine 211 (4,5-dichloro-2-n-octyl-3(2H) isothiazolone), one of the alternating organic booster compound used in antifouling paint to replace TBT, on marine benthic bivalve, we injected Sea-Nine 211 to clam, Pseudocardium sachalinensis, and then determined some xenobiotics metabolizing enzyme activities, especially EROD (ethoxyresorufin deethylase) and MROD (methoxyresorufin demethylase), in digestive gland during 4 day-exposure period. Moreover, the results were compared with those of TBT exposed clam. CYP1A1 dependant EROD activity in both the Sea-Nine 211 and the TBTC exposure groups showed no significant differences compared to those of the solvent control group. CYP1A2 dependant MROD activity in Sea-Nine 211 exposure group was significantly induced, but no significant difference was obtained in the TBTC exposure group. These results indicate that Sea-Nine 211 demonstrated a tendency to induce MROD activity, while TBTC inhibits the activities of this enzyme.

• Korean Journal of Food Science and Technology
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• v.22 no.3
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• pp.332-336
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• 1990

Antioxidative characteristics of freeze dried soybean sauce powder (SSP) on the oxidation reaction of linoleic acid mixture(LA) were evaluated by the determinations of peroxide formation, synergistic property, hydrogen donation and lipoxygenase activity. SSP was found to possess a considerable potentiality of antioxidant activity on the formation of hydroperoxides in the LA oxidation reaction system at $50^{\circ}C$ for 144hrs. This antioxidative effect was increased by the concentration from 0.02% to 0.5% of SSP in the reaction system. Under the condition of presence of ferric chloride (10 ppm) in the reaction system. appreciable effect of SSP on the synergistic antioxidation were observed. On the other hand, hydrogen donation property of SSP onto ${\alpha},\;{\alpha}'-diphenyl-{\beta}-picrylhydrazyl$ was found and inhibitory ability of SSP on LA oxidation was also shown in the reaction system of lipoxygenase-catalized oxidation.

• Applied Microscopy
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• v.26 no.4
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• pp.431-446
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• 1996

This experiment was performed to study the ultrastructural changes of the juxtaglomerular cell of mice following subcutaneous injection of heavy metallic agents. Male mice were divided into normal and experimental groups. The mice were subcutaneouly injected with $HgCl_2$ (2mg, 5mg or 10 mg/Kg/BW) or with $K_{2}Cr_{2}O_7$(5 mg, 10 mg or 20 mg/Kg/BW). Mice were sacrificed on 6 hours, 3 days and 14 days after the injection. Kidneys were fixed in the 2.5% glutaraldehyde-1.5% paraformaldehyde solution, followed by refixation in the 1% osmium tetroxide solution. Dehydrated blocks were embedded in araldite mixture. The sections were cut on a LKB-V ultratome, and ultrathin sections stained with uranyl acetate and lead citrate were observed with JEM 100CX II electron microscope. The results were as follow: 1. Juxtaglomerular cell of the experimental groups showed some alterations, especially in the structures of protein synthesis including dilations and degradations of granular endoplasmic reticula, atrophy of Golgi complex, and numerous free ribosomes in the cytoplasm. 2. Juxtaglomerular cells treated groups showed a number of vacuoles, protogranules and some myelin figures in the cytoplasm, especially in the earlier groups. 3. Juxtaglomerular cells of treated groups, contained a large number of secretory granules showing variable electron densities and pleomorphism in later groups (2 weeks). From the above results, it was concluded that, the mercuric chloride or potassium bichromate induces acute renin release from juxtaglomerular cells of the mice, but many juxtaglomerular cells may secrete prematured secretory granules, or the synthetic system of the cell can not perform normal function.

• Polymer(Korea)
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• v.36 no.5
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• pp.573-578
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• 2012

In general, most physical properties of wood/polyvinyl chloride (PVC) composites are lower than those of corresponding neat PVC resin because of poor interfacial adhesion between the hydrophilic wood flour and hydrophobic PVC. Therefore, in this study, we treated wood flour with three aminosilanes to improve wood/PVC interfacial adhesion strength, and eco-friendly wood/PVC/nanoclay composites were prepared by melt blending the aminosilane-treated wood flour, a heavy metal free PVC compound, and a type of nanoclay. The effects of treating wood flour with the aminosilanes and adding the nanoclay on the mechanical properties of the composites were investigated. Mechanical properties of the composites were investigated by universal testing machine (UTM), izod impact tester, dynamic mechanical analyzer (DMA), and thermomechanical analyzer (TMA). The tensile properties of the composites with the aminosilane-treated wood flour were considerably higher than those of the composites with neat wood flour. Furthermore, a small amount of the nanoclay improved mechanical properties of the composites. The performance of the wood/PVC composites was considerably improved by using the aminosilane-treated wood flour and the nanoclay.

• Journal of the Korean Chemical Society
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• v.30 no.1
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• pp.3-8
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• 1986

The investigation of the effect of solvent structure on the first-order solvolysis of cis-$[Co(en)_2ClNO_2]^+$ion has been extended to water + co-solvent mixtures where the co-solvents are glycerol, ethylene glycol, isopropyl alcohol and t-butyl alcohol. Rates of solvolysis have been evaluated by spectrophotometric method at temperature 25∼30$^{\circ}$C. The polarity of solvent has influence on the variation of rate constant. The non-linear plot of the rate constant in log scale versus $\frac{D-1}{2D+1}$ implies that change in solvent structure with composition plays an important role in determining the variation of rate constant. The linearity of the plot of the rate constant in log scale versus the Grundwald-Winstein Y factor confirms that the solvolysis is an Id-type process with considerable extension of the metal chloride bond in the transition state. In the Kivinen equation the slope of the plot of log k versus $log(H_2O)$ suggests that the solvolysis is also an Id-type process. The application of free energy cycle shows that the effect of solvent structure is greater in the transition state than in the initial state.

• The Journal of Korean Medicine
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• v.19 no.1
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• pp.349-357
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• 1998

The aim of this experiments was to investigate the effect of Semen Plantaginis extract on. the renal function, plasma renin activity, plasma levels of atrial natriuretic peptide and aldosterone in rats. The results obtained were as follows: 1. Water balance decreased significantly after the administration of Semen Plantaginis extract. 2. Urine volume increased significantly after the administration of Semen Plantaginis extract, 0.1ml/200g. 3. Urinary excretion of sodium decreased significantly after the administration of Semen Plantaginis extract, 0.1 ml/200 g, 2week. 4. Urinary excretion of potassium decreased significantly after the administration of Semen Plantaginis extract, 0.1 ml/200 g, 2week. 5. Urinary excretion of chloride decreased significantly after the administration of Semen Plantaginis extract. 6. Free water clearance increased significantly after the administration of Semen Plantaginis extract 0.1 ml/200 g, 2 week and 0.2 ml/200 g. 7. Urinary excretion of creatinine increased significantly after the administration of Semen Plantaginis extract. 8. Plasma renin activity decreased significantly after the administration of Semen Plantaginis extract, 0.2 ml/200 g. 9. Plasma levels of aldosterone decreased significantly after the administration of Semen Plantaginis extract. 10. Plasma levels of atrial natriuretic peptide (ANP) decreased significantly after the administration of Semen Plantaginis extract.

• The Korean Journal of Physiology
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• v.17 no.1
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• pp.29-35
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• 1983

The most popular way to get the animal to be co-operative for the animal experimentation is by using some kinds of general anesthetic agents. One of the most important point to take care of is, however, whether the agent(s) to be used is hinder the experimentation itself. There have been many contradictory reports of the general anesthetic agents on the renal function. Moreover, little information on the changes of the renal function by anesthesia has been available. We have done experiments to clarify and compare the effects of anesthesia induced by several general anesthetic agents on renal function in unanesthetized rabbits. Nembutal anesthesia(30 mg/kg, iv.) caused a decrease in free-water clearance, and increase in sodium and chloride excretion without significance. Thiopental anesthesia$(20{\sim}30\;mg/kg,\;iv.)$ suppressed all renal parameters tested. Chloralose(50 mg/kg, iv.) and chloral hydrate(75 mg/kg, iv.) did not change renal functions except for glomerular filtration rate, which parameter was suppressed only for a short period just after agent administration. Urethane(1 g/kg), administered by the route of either subcutaneously or intraperitoneally, suppressed renal functions lasted for the duration of experimental anesthesia. The above data suggest that it is very important to chose an appropriate anesthetic agents for a given experiment, especially experiment involved with renal function, and to interprete the data obtained from the anesthetized animal model for the expected results.