• The Journal of Internal Korean Medicine
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• v.20 no.1
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• pp.73-82
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• 1999

Nitric oxide (NO) is now recognized as a mediator of several biological and immunological functions, but unlike classical neurotransmitters. NO simply diffuse of the postsynaptic cells and around affecting cells. Taraxacum officinale (Compositae) has been used for maintenance of vitality, and they still occupy an important place in the traditional Korean medicine. We have examined that the effect of Taraxacum officinale water extract on NO synthesis in microglial cells of murine's brain, using the Griess method. And this study was evident that Taraxacum officinale did not induce NO production without recombinant interferon gamma ($rIFN-{\gamma}$), whereas Taraxacum officinale (10-1000 g/ml) with $rIFN-{\gamma}$ effectively produced NO in microglial cells of brain. As result. NO production in microglial cells increased most significantly in dose of 100 g/ml of the Taraxacum officinale and the production of NO was dependent on the dose of Taraxacum officinale, NG-monomethyl-L-arginine, competitive inhibitor of NO synthase, reduced the NO production by Taraxacum officinale stimulation with $rIFN-{\gamma}$ in microglial cells of murine. The effect of Taraxacum officinale was mainly dependent on Taraxacum officinale-induced tumor necrosis factor- secretion. Conclusively, this study suggested that Taraxacum officinale stimulate NO production at microglial cells in brain, which may be an important factor for mediating immune and neuroendocrinologic regulation in nervous system.

• Tribology and Lubricants
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• v.16 no.3
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• pp.223-230
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• 2000

Factors influencing friction reduction with MODTP(molybdenum dialkyl dithiophosphate) lubricant were investigated through a frictioning experiment using two-cylinder edge surface frictioning tester and XPS surface analysis. The friction reduction effect gained with MoDTP lubricant appeared to be largely attributable to MoS$_2$ formation on the frictioning interface. Under N$_2$ atmosphere, Mo diffused into the metal substrate, easily escaping from MoS$_2$ so the friction reduction effect from MoDTP was not gained. However, when an oxide surface film was preliminary prepared on frictioning surface, this Mo diffusion to metal substrate from MoS$_2$ was effectively inhibited. Then desired lubulication effect of MoDTP was gained even under N$_2$atmosphere. As such, the existence of a surface oxide film on the frictioning surface was concluded to be of essential importance in order to gain a lubrcating effect with MoDTP.

• Journal of Life Science
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• v.27 no.5
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• pp.509-516
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• 2017

Perilla frutescens (L.) Britton var. sprouts (PFS) is a plant of the labiatae family. The purpose of this work was to assess the preventive effects of PFS ethanolic extracts (PFSEs) on cytokine-induced ${\beta}$-cell damage. Cytokines, which are released by the infiltration of inflammatory cells around the pancreatic islets, are involved in the pathogenesis of type 1 diabetes mellitus. The combination of interleukin-$1{\beta}$ (IL-1), interferon-${\gamma}$ (IFN-${\gamma}$), and tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$) induced formation of reactive oxygen species (ROS). Accumulation of intracellular ROS led to ${\beta}$-cell dysfunction and apoptosis. PFSEs possess antioxidant activity and thus lead to downregulation of ROS generation. Cytokines decrease cell viability, stimulate the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), and induce the production of nitric oxide (NO). PFSEs prevented cytokine-induced cell viability in a dose-dependent manner. Incubation with PFSE resulted in significant reduction in cytokine-induced NO production that correlated with reduced levels of the iNOS and COX-2 protein expression. Furthermore, PFSE significantly decreased the activation of nuclear factor ${\kappa}B$ (NF-${\kappa}B$) by inhibition of $I{\kappa}B{\alpha}$ phosphorylation in RINm5F cells. In summary, our results suggest that the protective effects of PFSE might serve to counteract cytokine-induced ${\beta}$-cell destruction. Findings indicate that consumption of Perilla frutescens (L.) Britton var. sprouts alleviates hyperglycemia-mediated oxidative stress and pro-inflammatory cytokine-induced ${\beta}$-cell damage and thus has beneficial anti-diabetic effects.

• Journal of Life Science
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• v.13 no.4
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• pp.441-447
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• 2003

To examine the role of protein kinase C (PKC) in regulation of interleukin-1 beta (IL-1$\beta$)-induced iNOS expression, IL-1$\beta$-induced nitrite production was observed in cultured vascular smooth muscle (VSM) cells pretreated with phorbol 12-myristate 13-acetate (PMA) and phorbol 12,13-butyrate (PDB) as PKC activator; 4$\alpha$-phorbol-didecanoate (PDD) as PKC non-activator. Nitrite production induced by IL-1$\beta$ was increased by the presence of increasing concentration of PMA ranging from 2 to 200 nM. However, in VSM cells pretreated with PMA and PDB, IL-1$\beta$-induced $NO_2$ production was decreased in proportion to the duration of pretreatment, and most significantly decreased in pretreatment time of 24 hours. Using RT-PCR method, the expression of iNOS mRNA induced by IL-1$\beta$ was decreased in VSM cells pretreated with PMA 200 nM for 24 hours. These results suggest that decrease in IL-I$\beta$-induced nitrite production by the pretreatment of PMA result from inhibition of iNOS expression and the inhibition related to PMA-induced PKC down-regulation.

• KSBB Journal
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• v.17 no.1
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• pp.73-79
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• 2002

The method to optimize the microbial production of ethanol from CO using Clostridium ljungdahlii was developed. The kinetic parameter study on CO conversion with Clostridium ljungdahlii was carried out and maximum CO conversion rate of 37.14 mmol/L-hr-O.D. and $K_{m}$ / of 0.9516 atm were obtained. It was observed that method of two stage fermentation, which consists of cell growth stage and ethanol production stage, was effective to produce ethanol. When pH was shifted from 5.5 to 4.5 and ammonium solution was supplied to culture media as nitrogen source at ethanol production stage, the concentration of ethanol produced was increased 20 times higher than that without shift. Ethanol production from CO in a fermenter with Clostridium ljungdahlii was optimized and the concentration of ethanol produced was 45 g/L and maximun ethanol productivity was 0.75 g ethanol/L-hr.

• Journal of the Korean Applied Science and Technology
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• v.38 no.1
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• pp.217-227
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• 2021

In this study, Korean-cultivated Houttuynia cordata Thunb. (HC) was extracted anti-inflammatory effects of extracts were compared in order to confirm the possibility of natural cosmetics as a raw material. HPLC pattern analysis, cell viability assay, total phenolic contents, ABTS/DPPH radical scavenging analysis, measurement of ROS production, griess reagent assay, and luminex technique. The content of quercetin was higher in fresh Houttuynia cordata (HC-F) than in dried Houttuynia cordata (HC-D). Also, content of HC extracts shows a difference in the content of the two representative compounds (polyphenol and flavonoid) according to the stored differently. ROS production showed higher inhibitory rates at HC-F. The anti-inflammatory activity of HC-D was shown higher than that of HC-F. But, in the measurement of the reduction in inflammatory cytokines, IL-1β showed that HC-D had a relatively high reduction effect, and IL-6 and TNF-α showed a high reduction effect. And these results will be a basis for the development of cosmetology in skin care and improvement of skin problem.

• Korean Chemical Engineering Research
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• v.48 no.2
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• pp.185-192
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• 2010

The chemical-looping combustion(CLC) has advantages of no energy loss for separation of $CO_2$ without $NO_x$ formation. This CLC system consists of oxidation and reduction reactors where metal oxides particles are circulating through these two reactors. In the present study, the reaction kinetic equations of iron oxide oxygen carriers supported on bentonite have been determined by the shrinking core model. Based on the reactivity data, design values of solid circulation rate and solids inventory were determined for the rector. Two types of interconnected fluidized bed systems were designed for CLC application, one system consists of a riser and a bubbling fluidized bed, and the other one has a riser and two bubbling fluidized beds. Solid circulation rates were varied to about $30kg/m^2s$ by aeration into a loop-seal. Solid circulation rate increases with increasing aeration velocity and it increases further with an auxiliary gas flow into the loop-seal. As solid circulation rate is increased, solid hold up in the riser increases. A typical gas leakage from the riser to the fluidized bed is found to be less than 1%.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.31 no.2
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• pp.89-95
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• 2021

Research on the production of lithium hydroxide (LiOH) has been actively conducted in response to the increasing demand for high nickel-based positive electrode materials for lithium-ion batteries. Herein we studied the conversion of lithium oxide (Li2O) through thermal decomposition of lithium carbonate for the production of lithium hydroxide from lithium carbonate (Li2CO3). The reaction mechanism of lithium carbonate with alumina, quartz and graphite crucible during heat treatment was confirmed. When graphite crucible was used, complete lithium oxide powder was obtained. Based on the TG analysis results, reagent-grade lithium carbonate was heat-treated at 700℃, 900℃ and 1100℃ for various time and atmosphere conditions. XRD analysis showed the produced lithium oxide showed high crystallinity at 1100℃ for 1 hour in a nitrogen atmosphere. In addition, several reagent-grade lithium oxides were reacted at 100℃ to convert to lithium hydroxide. XRD analysis confirmed that lithium hydroxide (LiOH) and lithium hydroxide monohydrate (LiOH·H2O) were produced.

• Journal of Life Science
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• v.12 no.4
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• pp.442-451
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• 2002

In oder to investigate the effects of pH and temperature on the formation of bromate ion, which is ozonation by-products of bromine containing natural water. At the same intial pH condition, the increase of pH shown similar trends even if the reaction variables such as temperature and reaction time of ozonation were changed. As pH and temperature were increasing, the bromate concentration was increased but bromine components (HOBr/OBr-) were decreased with increasing pH from 3 to 10. Lipid peroxide content in the kidney was increased by bromate which was ingestion with 0.4g/L for 24 weeks in drinking water. Renal cytosolic enzyme system (XO, AO) of bromate group were significantly increased in comparison with those of normal group. But microsomal enzyme system were not affected. BUN level and urinary ${\gamma}$-glutamyltransferase activity were significantly increased in comparison with those of the normal. But, urinary lactate dehydrogenase activity was not affected. Renal glutathione content of rat was significantly decreased in comparison with those of normal rat given bromate. Renal glutathione S-transferase and ${\gamma}$-glutamylcysteine synthetase activities were significantly decreased in bromate-treated group, but change in renal glutathione reductase activity was not significantly different from any other experimental group.

• Applied Chemistry for Engineering
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• v.26 no.4
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• pp.495-504
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• 2015

This work investigated the characteristics of a packed-bed plasma reactor system and the performances of the plasma reactors connected in series or in parallel for the decomposition of ethylene. Before the discharge ignition, the effective capacitance of the ${\gamma}$-alumina packed-bed plasma reactor was larger than that of the reactor without any packing, but after the ignition the effective capacitance was similar to each other, regardless of the packing. The energy of electrons created by plasma depends mainly on the electric field intensity, and was not significantly affected by the gas composition in the range of 0~20% (v/v) oxygen (nitrogen : 80~100% (v/v)). Among the various reactive species generated by plasma, ground-state atomic oxygen and ozone are understood to be primarily involved in oxidation reactions, and as the electric field intensity increases, the amount of ground-state atomic oxygen relatively decreases while that of nitrogen atom increases. Even though there are many parameters affecting the performance of the plasma reactor such as a voltage, discharge power, gas flow rate and residence time, all parameters can be integrated into a single parameter, namely, specific input energy (SIE). It was experimentally confirmed that the performances of the plasma reactors connected in series or in parallel could be treated as a function of SIE alone, which simplifies the scale-up design procedure. Besides, the ethylene decomposition results can be predicted by the calculation using the rate constant expressed as a function of SIE.