• Corrosion Science and Technology
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• v.18 no.2
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• pp.39-48
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• 2019

The feasibility of using benzotriazole (BTAH) to inhibit pitting corrosion in the sprinkler copper tubes was investigated by filling the tubes with BTAH-water solution in 829 households at an eight-year-old apartment complex. The water leakage rate was reduced by approximately 90% following BTAH treatment during 161 days from the previous year. The leakage of one of the two sprinkler copper tubes was investigated with optical microscopy, scanning electron microscopy, energy dispersive spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction analysis to determine the formation of Cu-BTA film inside the corrosion pits. All the inner components of the corrosion pits were coated with Cu-BTA films suggesting that BTAH molecules penetrated the corrosion products. The Cu-BTA film was about 2 nm in thickness at the bottom of a corrosion pit. A layer of CuCl and $Cu_2O$ phases lies under the Cu-BTA film. This complex structure effectively prevented the propagation of corrosion pits in the sprinkler copper tubes and reduced the water leakage.

• Korean Journal of Food Science and Technology
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• v.29 no.1
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• pp.161-166
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• 1997

Tissue thromboplastin (tissue factor), a membrane bound glycoprotein is an important initiating factor in blood coagulation cascade, which leads to the formation of thrombin by activating both factor X and IX. Activation of blood coagulation by TF is essential for blood injury, and stimulates the blood coagulation in myocardial infarction, cancer and blood coagulatory diseases. High density lipoprotein, apolipoprotein A-II were known to be biological TF inhibitors. Recently, studies on search for TF inhibitors from natural products have been active in Korea. Among the edible mushrooms screened for inhibitory activities on the TF, Lentinus edodes showed the most strong activity, followd by Agaricus bisporus and Ganoderma lucidium. And the fractionation of the above mushrooms with the chloroform ($CHCl_3$) and ethylacetate (EtOAc) was done and evaluated for the inhibitory activities on TF. In Ganoderma lucidium, $CHCl_3$ fraction and $H_2O$ layer were not active, but EtOAc fraction exhibited a strong inhibitory activity on TF and the $IC_{50}$ value was $1.07{\times}10^{-4}\;g$. In the case of Agaricus bisporus, there were no inhibitory activities on the TF in all of the fractions. $CHCl_3$ fraction and $H_2O$ layer of Lentinus edodes did not show inhibition on the TF but EtOAc fraction showed strong inhibition on the TF, and the $IC_{50}$ value was $7.70{\times}10^{-4}\;g$.

• Food Science and Biotechnology
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• v.17 no.2
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• pp.302-307
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• 2008

Novel amylase inhibitors were synthesized via transglycosylation by Thermotoga maritima glucosidase (TMG). TMG hydrolyzes acarbose, acarviosine-glucose, and maltooligosaccharide by releasing $^{14}C$-labeled glucose from the reducing end of each molecule. When TMG was incubated with acarviosine-glucose (the donor) and glucose (the acceptor), two major transfer products, compounds 1 and 2, were formed via transglycosylation. The structures of the transfer products were determined using thin-layer chromatography (TLC), high-performance ion chromatography (HPIC), and $^{13}C$ nuclear magnetic resonance (NMR) spectroscopy. The results indicate that acarviosine was transferred to glucose at either C-6, to give a $\alpha-(1{\rightarrow}6$) glycosidic linkage, or at C-3, to produce an $\alpha-(1{\rightarrow}3$) glycosidic linkage. The transfer products showed a mixed-type inhibition against porcine pancreatic $\alpha$-amylase; therefore, they may be useful not only as inhibitors but also as acarbose transition-state analogs to study the mechanism of amylase inhibition.

• Journal of Periodontal and Implant Science
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• v.23 no.2
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• pp.243-259
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• 1993

The bone resorbing activity of $PGE_2$ and elevated level of prostaglandins(PGs) and thromboxanes (TXs) in inflamed gingiva which are cyclooxygenase(C) metabolites have been well documented. Nonsteroidal anti-inflammatory drugs(NSAIDs) have been known to suppress gingival inflammation and bone resorption through the specific inhibitory action on the C pathway thereby decrease of various C metabolites. Recent studies provide unequivocal results that gingival tissue metabolizes arachidonic acid(AA) mainly through lipoxygenase(L) pathway. And the results of our previous experiments suggest that indomethacin may have inhibitory action on L as well as C. Thus we started this study to show the influences of several C inhibitors on the L activity at therapeutic and toxic dosage. Periodontal tissue samples were obtained from patients with advanced periodontitis and incubated with $^{14}C-AA(0.2{\mu}Ci)$ and various enzyme inhibitors. The tissue lipid extracts were separated by means of thin layer chromatography(TLC) and analyzed by means of autoradiography and TLC analyzer. Our results showed that aspirin inhibited C more selectively than L, however at higher concentration it also decreased HETEs production significantly. Indomethacin showed dose-dependent inhibition of L as well as C and all of the L metabolites were decreased to the same degree by high concentration of indomethacin. AA-861, which is an experimental tool of selective L inhibitor, showed inhibition of HETEs production but no effect on the production of $TXB_2$, PGs and $LTB_4$. Various propionic acid derivatives NSAIDs(ibuprofen, flurbiprofen, naproxen) showed the same patterns of effect on AA metabolism each other that was profound inhibition of PGs production, to the less degree HETEs and $TXB_2$ production, and of no effect on the $LTB_4$ production.

• Korean Journal of Weed Science
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• v.15 no.4
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• pp.247-253
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• 1995

The herbicide butachlor [N-(butoxymethyl)-2-chloro-N-(2,6-di-methylphenyl) acetamide] is widely used by farmers as a tool for weed management of transplanted rice(Oryza sativa L.) in Taiwan. The herbicide did not stop germination of rice and weed seeds, but strongly inhibited the subsequent growth of young shoots and roots. The inhibition was also strong on established seedlings. However, they could recover to normal growth after the herbicide effect disappeared. Butachlor greatly decreased the endogenous indole-3-acetic acid (IAA) but increased the endogenous abscisic acid (ABA) contents of rice seedlings. Addition of lAA into growth medium (Hoagland's solution) partly relieved growth inhibition. Pretreatment of both gibberellic acid ($GA_3$) and IAA 24 hours before butachlor treatment almost completely alleviated the butachlor-interfere with GA and/or IAA metabolism or their action resulting in the growth inhibition of rice. Butachlor was readily absorbed by rice roots. During 24 hours of uptake experiment, 32% of the applied herbicide was absorbed. Pretreatment of the herbicide for 2 days did ncx affect the absorption. Of the absorbed herbicide, 80% remained in roots, only 20% transported into shoots, and more than 50% was metabolized to water soluble substances. Thin-layer chromatographic (TLC) analysis indicated that the Rf value of the most abundant metabolite was butachlor-glutathione conjugate. Rice, barnyardgrass (Echinochloa crus-galli (L.) Beauv.), and monochoria (Monochoria vaginalis Presl) seedlings contained relatively high level of non-protein thiols, while the glutathione S-transferase (GST) activity was found highest in rice, barnyardgrass the next, monochoria the lowest. The difference in GST activity among these species might be related to their sensitivity to butachlor.

• Corrosion Science and Technology
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• v.7 no.5
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• pp.283-287
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• 2008

The drag reduction agency (DRA) for gas pipeline, a novel method used for reducing friction or drag on a gas flowing to increase the transmission efficiency of gas pipeline, is a more flexible and economical technology than internal flow efficient coatings. In this paper, an effective DRA has been developed in Authors' Institute by analyzing the hydrodynamic friction resistance on internal gas pipeline and then studying the work mechanism and molecular structure of DRA. In the meantime, a group of property test for selecting DRA material has been determined, including viscosity, contact angle, volatility, corrosion, slab extending, and flow behavior in horizontal tube. The inhibition efficiency and drag reduction efficiency of the developed DRA have been investigated finally based on the relevant test methods. Results of corrosion test show that the developed DRA has very good inhibition effect on mild steel by brushing a thin layer of DRA on steel specimens, giving inhibition efficiency of 91.2% and 73.1% in 3%NaCl solution and standard salt fog environment respectively. Results of drag-reducing test also show that the Colebrook formula could be used to calculate friction factors on internal pipes with DRA as the Reynolds number is in the range of $0.75\times10^5\sim2.0\times10^5$. By comparing with normal industrial pipes, the friction resistance coefficient of the steel pipe with DRA on internal wall decreases by 13% and the gas flux increases by 7.3% in testing condition with Reynolds number of $2.0\times10^5$.

• Journal of the Korean Magnetics Society
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• v.11 no.2
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• pp.63-71
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• 2001

The effects of an Ag seed layer on the magnetic properties and the microstructural evolution of SmCo/Cr thin films deposited on glass substrates were investigated. Coercivity of the films is 2.0 kOe when the thickness of Ag seed layer was 1nm thick, but it increased to 2.7 kOe when the Ag seed layer thickness is 3 nm. The increase of coercivity for film with 3 nm-thick Ag is due to roughness of Cr and grain size of Cr by the Ag microbumps. Ar partial pressure influenced on the formation of Ag microbumps, for example, they were formed at 5 mTorr when Ag thickness was 1 nm. The mechanism of magnetization reversal of the SmCo films changed from domain wall motion to domain rotation as the Ag inserted. This was thought to be due to inhibition of domain wall motion by the reduction of Cr grain size and the increase of roughness.

• Journal of the Korean Ceramic Society
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• v.46 no.6
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• pp.596-601
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• 2009

Double-layered ZnO nanostructures have been synthesized by aqueous solution method on (001) plane of ZnO nanorod. A stepwise changing of aqueous solution concentration gave rise to a new nano-structured layer consisting of either multiple of nanorods or nanowires with much smaller radii than that of the ZnO nanorod on which the new layer was grown. As the first step the ZnO nanorods have been grown to have the (001) preferential orientation in the aqueous solution consisting of 0.1M zinc nitrate and 0.1 M HMT. This preferentially aligned ZnO nanorods have been regrown in either a less diluted solution of 0.01M zinc nitrate and 0.01 M HMT or a more diluted solution of 0.005M zinc nitrate and 0.01 M HMT. A new nano-layer consisting of numerous aligned nanorods or nanowires has been produced on the (001) planes of ZnO nanorods. The growth mechanism for this double layered ZnO nanostructure is ascribed to the (001) polar surface energy instability and inhibition of (001) plane growth due to the step-wise change of aqueous solution concentration; ZnO nuclei formed on the (001) plane grow preferentially in (010) plane instead of (001) plane to reduce the total surface energy. Surface area of ZnO nanostructure can be increased in orders of magnitudes by forming a new layer consisting of smaller nanorods/nanowires on (001) plane of ZnO nanorods.

• Food Science and Biotechnology
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• v.17 no.2
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• pp.274-278
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• 2008

Ethanol extracts from the edible mushroom hinmogi (Tremella fuciformis, TF) were used in the investigation of effects on $\alpha$-glucosidase in vitro and on glucose-uptake in 3T3-L1 mature adipocytes. Addition of the extract significantly inhibited $\alpha$-glucosidase from small intestine of porcine and of rat (about 42 and 35% of control, respectively), and stimulated glucose uptake (about 100% of control), of which activity was higher than that of maitake (Grifola frondosa) X-fraction, a well known anti-diabetic substance. When the ethanol extracts were further partitioned successively by organic solvents and purified by silica gel chromatography, the non-polar layer (F-7) from hexane layer showed highest stimulatory activity of glucose-uptake among layers tested. The major components of the F-7 were 1-monooleoylglycerol and 1-monopalmitoylglycerol. Our report is the first description of TF with stimulatory activity of glucose-uptake. These results suggest that TF extracts may constitute a new source of glucose transport activator and could be employed as a potential anti-diabetic material for treatment and preventing diabetes.

• Korean Journal of Pharmacognosy
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• v.42 no.2
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• pp.169-174
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• 2011

In this study, we investigated on antioxidative activity, antibacterial activity and tyrosinase inhibitory activity in 75% ethanol extracts of bark and cork layer from Prunus sargentii. The total polyphenol content of cork and bark extract was found to be 217.4 mg/g and 184.3 mg/g. And flavonoid content was found to be 31.9 mg/g and 58.6 mg/g respectively. In DPPH radical scavenging ability, cork extract was exhibited stronger scavenging ability than bark extract. Moreover, cork extract was showed higher inhibitory activity than bark extract in tyrosinase inhibitory activity. In antibacterial activity, bark extract was showed higher growth inhibition effect than cork extract against tested bacterial strains. In measurement of cytotoxicity by MTT assay, bark and cork extract showed fine cell viabilities(95.7~120.9%) against RAW 264.7 cell.