• Applied Chemistry for Engineering
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• v.23 no.6
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• pp.561-566
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• 2012

PtRuW/C catalysts were prepared with the different molar ratios of Pt : Ru : W and their compositions were analyzed by energy dispersive X-ray (EDX). The uniform distribution of particles was observed using transmission electron microscopy (TEM). An average crystalline size of 3.5~5.5 nm was calculated based on x-ray diffraction (XRD) data. The electrochemical properties such as electrochemically active surface areas, current densities, specific activities and poisoning rates, were analyzed via CO stripping, linear sweep voltammetry and chronoamperometry. From the analysis, we observed that ternary alloy catalysts, except $PtRu_2W_2/C$, have higher current densities, specific activities and stabilities than those of commercial binary catalysts. Among all in-house catalysts, Pt5Ru4W/C showed the highest specific activity of $121.05mA{\cdot}m^{-2}$ and the lowest poisoning rate of $0.01%{\cdot}s^{-1}$.

• Korean Chemical Engineering Research
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• v.46 no.1
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• pp.194-199
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• 2008

In this study, the effective method to esterify the free fatty acids in jatropha oil was examined. Compared to other plant oils, the acid value of jatropha oil was remarkably high, 11.5 mgKOH/g. So direct transesterification by a base catalyst was not suitable for the oil. After the free fatty acids were esterified with methanol, jatropha oil was transesterified. The activities of four solid acid catalysts were tested and Amberlyst-15 showed the best activity for the esterification. After constructing the experiment matrix based on RSM and analyzing the statistical data, the optimal esterification conditions were determined to be 6.79% of methanol and 17.14% of Amberlyst-15. After the pretreatment, jatropha biodiesel was produced by the transesterification using KOH in a pressurized batch reactor. Jatropha biodiesel produced could meet the major specifications of Korean biodiesel standards; 97.35% of FAME, 8.17 h of oxidation stability, 0.125% of total glycerol and $0^{\circ}C$ of CFPP.

• Journal of the Korean Chemical Society
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• v.36 no.6
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• pp.894-905
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• 1992

Dioxygen binding and homogeneous catalytic oxidation of hydrazobenzene were investigated by employing tetradentate Schiff base Cobalt(II) complexes such as Co(II)(SED)$(Py)_2$, Co(II)(SOPD)$(Py)_2$ and Co(II)(SND)$(Py)_2$ in saturated oxygen methanol solvent. The major product of hydrazobenzene ($H_2$AB) oxidation by catalysts of superoxo type [Co(III)(SED)(Py)$O_2$] and [Co(III)(SOPD)(Py)$O_2$] complexes are trans-azobenzene (t-AB) and rate constants k for oxidation reaction was 7.692 ${\times}$ $10^{-2}$ M/sec for [Co(III)(SED)(Py)$O_2$] and 5.076 ${\times}$ $10^{-2}$ M/sec for [Co(III)(SOPD)(Py)$O_2$]. But cis-azobenzene (c-AB) are obtained as a major product with ${\mu}$-peroxo type [Co(III)(SED)(Py)]$_2O_2$ catalyst, and rate constant k is 1.266 ${\times}$ $10^{-2}$ M/sec. The rate constants of oxidation reaction has been studied spectrophotometrically and the rate law established. A mechanism involving a intermediate activated complexes of catalyst, hydrazobenzene and oxygen has been proposed. $H_2$AB + Co(II)(Schiff base)$(Py)_2$ + $O_2$ ${\rightleftharpoons}_{MeOH}^K$ Co(III)(Schiff base)(Py)$O_2$${\cdot}$$H_2$AB + Py $\longrightarrow^k$ Co(II)(Schiff base)$(Py)_2$ + t-AB + $H_2O_2$(Scchiff base : SED and SOPD). $H_2$AB + 2Co(II)(SND)$(Py)_2$ + $O_2$ ${\rightleftharpoons}_{MeOH}^K$ [Co(III)(SND)(Py)]$_2O_2$${\cdot}$H_2$AB + 2Py ${\longrightarrow}^k$ (Co(II)(SND)$(Py)_2$ + c-AB + $H_2O_2$.

• Korean Chemical Engineering Research
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• v.51 no.4
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• pp.443-454
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• 2013

Various metal ions (transition and base metals) incorporated MCM-41 catalysts can be synthesized using colloidal and soluble silica with non-sodium involved process. Transition metal ion-typically $V^{5+}$, $Co^{2+}$, and $Ni^{2+}$-incorporated MCM-41 catalysts were synthesized by isomorphous substitution of Si ions in the framework. Each incorporated metal ion created a single species in the silica framework, single-site solid catalyst, showing a substantial stability in reduction and catalytic activity. Radius of pore curvature effect was investigated with Co-MCM-41 by temperature programmed reduction (TPR). The size of metallic Co clusters, sub-nanometer, could be controlled by a proper reduction treatment of Co-MCM-41 having different pore size and the initial pH adjustment of the Co-MCM-41 synthesis solution. These small metallic clusters showed a high stability under a harsh reaction condition without serious migration, resulting from a direct anchoring of small metallic clusters to the partially or unreduced metal ions on the surface. After a complete reduction, partial occlusion of the metallic cluster surface by amorphous silica stabilized the particles against aggregations. As a probe reaction of particle size sensitivity, carbon single wall nanotubes (SWNT) were synthesized using Co-MCM-41. A metallic cluster stability test was performed by CO methanation using Co- and Ni-MCM-41. Methanol and methane partial oxidations were carried out with V-MCM-41, and the radius of pore curvature effect on the catalytic activity was investigated.

• Journal of Applied Biological Chemistry
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• v.57 no.4
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• pp.373-377
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• 2014

In this study, we demonstrated whether the extract of Fomes fomentarius (FFE; FF extract) could be used to stimulate macrophages (RAW 264.7 cells). All four doses of FFE (5, 10, 20, and $40{\mu}g/mL$) had no significant cytotoxicity during the entire experimental period. FFE potently increased the production of nitric oxide (NO). Consistent with these observations, inducible NO synthase levels were increased by FFE in a dose-dependent manner. Moreover, FFE increased the production of tumor necrosis factor-${\alpha}$, interleukin (IL)-$1{\beta}$, and IL-6 in the same cells. These stimulating effects of FFE were found to be caused by the stimulation of phosphorylation of $I{\kappa}B{\alpha}$ and MAP kinases (p38, ERK, and JNK). These results suggest that FFE may be used as new agents for wide application in the immune study of mushroom.

• Korean Journal of Food Science and Technology
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• v.12 no.4
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• pp.235-241
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• 1980

Equal portions of a Maillard-type browning mixture (0.2 M glucose+0.2 M glycine), heated at $100^{\circ}C$ for 12 hr, were extracted with the same amounts of eight solvents, respectively. The extracts were then dissolved in equal amounts of an edible soybean oil, and the resulting substrates and a portion of the soybean oil (Control) were stored in an incubator kept at $45.0{\pm}1.0^{\circ}C$ for three weeks. Peroxide values and TBA values of Control and the substrates were determined regularly during the storage period. The POVs of Control and the substrates containing acetone, benzene, chloroform, ethanol, diethyl ether, methanol, methylene chloride, and petroleum ether extracts after 12 days of storage were respectively $60.0{\pm}3.6$, $31.9{\pm}0.9$, $37.6{\pm}2.2$, $48.1{\pm}1.1$, $11.9{\pm}1.3$, $4.85{\pm}0.4$, $11.5{\pm}1.0$, $45.3{\pm}0.3$, and $43.3{\pm}4.2\;m.\;mole/kg\;oil$. The TBA values after 16 days of storage were respectively $0.28{\pm}0.02$, $0.20{\pm}0.01$, $0.21{\pm}0.01$, $0.26{\pm}0.03$, $0.16{\pm}0.02$, $0.28{\pm}0.02$, $0.17{\pm}0.01$, $0.33{\pm}0.05$, and $0.31{\pm}0.02$. The induction periods (arbitrarily taken as the time in hours for a substrate to reach a peroxide value of 30 m. mole/kg oil) of Control and the substrates were respectively 193, 280, 252, 220, 478, 229, 455, 217, and 214 hr. The antioxidant activity of each extract estimated on the basis of the length of the induction periods was, in decreasing order, as follows; ethanol>methanol>acetone>benzene>diethyl ether>chloroform, pertroleum ether, methylene chloride.

• Korean journal of applied entomology
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• v.45 no.1 s.142
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• pp.31-36
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• 2006

Inflammation in the brain has known to be associated with the development of a various neurologiacal diseases. The hallmark of neuro-inflammation is the activation of microglia, brain macrophage. Pro-inflammatory compounds including nitric oxide(NO) are the main cause of neuro-degenerative disease such as Alzheimer's disease. In the study, we examined whether Harmonia axyridis extracts inhibit the NO production by a direct method using Griess reagent, western blotting and by RT-PCR(Reverse Transcription-Polymerase Chain Reactionin) the gene expression of inducible nitric oxide synthase(iNOS). Distilled water$(H_2O)$ and methanol(MeOH) extracts of H. axyridis inhibited the protein expression of TNF-a(Tumor Necrosis Factor) and IL-6(Interleukin) in LPS (Lipopolysaccharide) stimulated BV-2 cells at the concentration of 100 ng/ml. Incubation of BV-2 cells with the extracts of $H_2O$ of MeOH inhibited the LPS induced NO and iNOS protein. And this inhibition of iNOS protein is concordant with the inhibition of iNOS mRNA expression. These data suggested that H. axyridis extracts may play a crucial role in inhibiting the NO production.

• Korean Journal of Materials Research
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• v.30 no.1
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• pp.14-21
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• 2020

Carbon supports for dispersed platinum (Pt) electrocatalysts in direct methanol fuel cells (DMFCs) are being continuously developed to improve electrochemical performance and catalyst stability. However, carbon supports still require solutions to reduce costs and improve catalyst efficiency. In this study, we prepare well-dispersed Pt electrocatalysts by introducing titanium dioxide (TiO₂) into biomass based nitrogen-doped carbon supports. In order to obtain optimized electrochemical performance, different amounts of TiO₂ component are controlled by three types (Pt/TNC-2 wt%, Pt/TNC-4 wt%, and Pt/TNC-6 wt%). Especially, the anodic current density of Pt/TNC-4 wt% is 707.0 mA g^-1_pt, which is about 1.65 times higher than that of commercial Pt/C (429.1 mA g^-1_pt); Pt/TNC-4wt% also exhibits excellent catalytic stability, with a retention rate of 91 %. This novel support provides electrochemical performance improvement including several advantages of improved anodic current density and catalyst stability due to the well-dispersed Pt nanoparticles on the support by the introduction of TiO₂ component and nitrogen doping in carbon. Therefore, Pt/TNC-4 wt% may be electrocatalyst a promising catalyst as an anode for high-performance DMFCs.

• Journal of Mushroom
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• v.14 no.4
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• pp.220-224
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• 2016

Chronic inflammation, which results from continuous exposure to antigens, is one of major reasons for tissue damage and diseases such as rheumatoid arthritis and type 2 diabetes. In this study, we investigated the anti-inflammatory effects of extracts (hexane, $CHCl_3$, MeOH, $MeOH/H_2O$, and $H_2O$) from GW10-45, which is our new cultivar of an edible mushroom Pleurotus ferulae (ASI 2803 and ASI 2778), in RAW264.7 murine macrophages. None of the extracts showed cytotoxicity in RAW264.7 cells and the hexane, CHCl and H extracts reduced nitric oxide (NO) production, an important inflammatory marker, in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. Particularly, the extract (CG45) inhibited NO production more than the other extracts did. To elucidate the effects of CG45 on molecular targets involved in pro-inflammatory responses, we performed western blot analysis. Expression of inducible nitric oxide (iNOS) significantly decreased in LPS and CG45 co-incubated cells compared to that in LPS only-treated cells. Additionally, another protein thatplays a critical role in inflammation, was down-regulated in cells treated with both LPS and CG45. In the nuclear factor $(NF)-{\kappa}B$ pathway, phosphorylation of $I{\kappa}B{\alpha}$ decreased in RAW264.7 cells treated with both LPS and CG45. Furthermore, CG45 inhibited the phosphorylation of $NF-{\kappa}B$ in LPS-stimulated RAW264.7 cells. Conclusively, CG45 could suppress pro-inflammatory responses in LPS-stimulated RAW264.7 cells by down-regulating not only the phosphorylation of $NF-{\kappa}B$ and $I{\kappa}B{\alpha}$ but also the expression of iNOS and COX-2 without any cytotoxicity.

• Resources Recycling
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• v.15 no.4 s.72
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• pp.3-12
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• 2006

The feasibility for the employment of manganese nodule as an adsorbent for $SO_{2}$ gas has been investigated. The specific surface area of manganese nodule particle, which used in the experiments, was ca. $221.5m^{2}/g$ and the content of sulfur in manganese nodule was observed to significantly increase after $SO_{2}$ was adsorbed on it. The EPMA for the distilled water-washed and methanol-washed manganese nodule particle after $SO_{2}$ adsorption showed that its sulfur content was slightly decreased to 14.7% and 13.1% respectively, from 15.4% before washing. The XRD analysis of manganese nodule showed that todorokite and birnessite, which are manganese oxides, and quartz and anorthite were the major mineralogical components and weak $MnSO_{4}$ peaks were detected after $SO_{2}$ was adsorbed on manganese nodule. For an comparative investigation, limestone was also tested as an adsorbent for $SO_{2}$, however, no peaks for $CaSO_{4}$ were found by XRD analysis after the adsorption of $SO_{2}$. As the size of adsorbent increased, time for breakthrough was decreased and the adsorbed amount of $SO_{2}$ was also diminished. The $SO_{2}$ adsorption was hindered when its flow rate became high and the adsorption capacity of manganese nodule was observed to be superior to that of limestone. In addition, the mixture of manganese nodule and limestone did not show an increase in the adsorption of $SO_{2}$. Finally, as the temperature was raised, the adsorbed amount of adsorbate on manganese nodule was found to be decreased.