• Journal of Mushroom
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• v.18 no.2
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• pp.151-163
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• 2020

Antioxidant activities and contents of β-glucan and amino acids of wild mushrooms collected from Geosan, Boeun, Eumseong, and Bonghwa in Korea were investigated. Phaeolus schweinitzii (OK1165) displayed the highest 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity (60.3%), ferric reducing antioxidant power (3.84), reducing power (1.05), nitrite scavenging activity (96.4%), total polyphenol content (54.7 mg gallic acid equivalent/g), and flavonoid content (19.98 mg quercetin equivalent/g). The β-glucan content of Pycnoporus cinnabarinus (OK1172) of 51.9% was higher than the contents of the other mushrooms. P. schweinitzii (OK1165) displayed the highest total amino acid (1,373.9 mg/kg) and essential amino acid (515.0 mg/kg) contents among the wild mushrooms. The findings confirmed that wild mushrooms could be a high-value resource for functional foods with pronounced antioxidant activity. The results also provide fundamental data for extracting useful compounds from wild mushrooms.

• Journal of Mushroom
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• v.18 no.2
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• pp.164-173
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• 2020

The extracts of four species of ectomycorrhizal mushrooms-Cantharellus cinnabarinus (OK1247), Lactarius parallelus (OK1264), Tricholoma matsutake (OK1282), and Ramaria botrytis (OK1283)-were prepared to determine their antioxidant activities and nutritional properties. R. botrytis extract displayed the highest 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity (33.8%), ferric reducing antioxidant power (0.38), reducing power (0.35), total polyphenol (13.83 mg gallic acid equivalent/g), and flavonoid contents (2.56 mg quercetin equivalent/g). L. parallelus extract displayed the highest nitrite scavenging activity. Analysis of amino acid contents revealed that C. cinnabarinus extract had the highest total amino acid (1,046.1 mg/kg) and essential amino acid (404.9 mg/kg) contents, while R. botrytis extract had the lowest total amino acid (708.3 mg/kg) and essential amino acid (247.3 mg/kg) contents. Among the amino acid components detected in the four ectomycorrhizal mushrooms, cysteine was the most abundant, accounting for 14.3~20.7%, followed by phenylalanine, which accounted for 9.5~13.4% of all amino acids. In summary, the antioxidant activities were the highest in R. botrytis extract, and the amino acid content was the highest in C. cinnabarinus extract, among the four ectomycorrhizal mushrooms.

• Journal of Mushroom
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• v.19 no.1
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• pp.41-50
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• 2021

The aim of the study was to obtain the extracts of various native wild mushrooms and select the useful resources though biological activity evaluation. The anti-oxidant potential, nitrite scavenging activity, and ��-glucan content of wild mushrooms collected from Eumseong and Bonghwa in Korea were investigated. Based on the results of this study, Ganoderma lingzhi (OK1362) showed the highest DPPH radical scavenging activity (73.2%), ferric reducing anti-oxidant power (0.134), reducing power (0.155), nitrite scavenging activity (53.6%), total polyphenol content (28.9 mg GAE/g), flavonoid content (10.0 mg QE/g), and ��-glucan content (25.2%) when compared to other wild mushrooms sampled in this study. In addition, it was confirmed that Perenniporia fraxinea (OK1360), Amanita sp. (OK1398), and Russula sp. (OK1406) had relatively high anti-oxidant and nitrite scavenging potentials. In conclusion, our results can provide fundamental data for extracting beneficial compounds from wild mushrooms.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 1999.10a
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• pp.209-210
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• 1999

오존 precursor인 NOx의 배출기준은 점차 강화되고 있고 NOx의 처리기술로는 선택적 촉매환원법 (Selective Catalytic Reduction; SCR)이 가장 널리 사용되고 있다. 국내 SCR 적용공정의 경우, 100% 수입에 의존하고 있어 support 촉매의 국산화가 절실히 요구되고있다. 이에 본 연구에서는 support로 섬유형 세라믹 필터를 사용하여 CuO, V$_2$O$_{5}$ 촉매를 담지시켜 NOx의 제거실험을 수행하였다.(중략)

• 대한예방의학회:학술대회논문집
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• 1996.10a
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• pp.329-330
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• 1996

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1999.04a
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• pp.62-63
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• 1999

Reduction 2,4,6-Trinitrotoluene by zero valent iron was studied in a batch reactor under anoxic conditions. Results showed that the removal of TNT was a pseudo-first order and the rate was dependent on the available metal surface area. Final product, presumably triaminotoluene, accumulated in the solution as well as on the metal surface. However, little amounts of aminodinitrotoluenes were detected. Therefore, it is postulated that the reduction of nitro group occurs simultaneously in all three position.

• Applied Chemistry for Engineering
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• v.35 no.4
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• pp.296-302
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• 2024

An ionic conjugated polymer-iron (III) chloride composite was prepared via in-situ quaternization polymerization of 2-ethynylpyridine (2EP) using iron (III) chloride. Various instrumental methods revealed that the chemical structure of the resulting conjugated polymer (P2EP)-iron (III) chloride composite has the conjugated backbone system having the designed pyridinium ferric chloride complexes. The polymerization mechanism was assumed to be that the activated triple bond of 2-ethynylpyridinium salt, formed at the first reaction step, is easily susceptible to the step-wise polymerization, followed by the same propagation step that contains the propagating macroanion and monomeric 2-ethynylpyridinium salts. The electro-optical and electrochemical properties of the P2EP-FeCl₃ composite were studied. In the UV-visible spectra of P2EP-FeCl₃ composite, the absorption maximum values were 480 nm and 533 nm, and the PL maximum value was 598 nm. The cyclic voltammograms of the P2EP-FeCl₃ composite exhibited irreversible electrochemical behavior between the oxidation and reduction peaks. The kinetics of the redox process of composites were found to be very close to a diffusion-controlled process from the plot of the oxidation current density versus the scan rate.

• Journal of the Mineralogical Society of Korea
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• v.21 no.2
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• pp.161-175
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• 2008

The soil developed from volcanic ash in Jeju Island, Korea, were classified as typical Andisols. The soils had acidic pH, high water contents, high organic matters and clay-silty textures. The crystalline minerals of the samples were mainly composed of ferromagnesian minerals such as olivine and pyroxene, and iron oxides such as magnetite and hematite derived from basaltic materials. A large amount of gibbsite was found at the subsurface horizon as a secondary product from the migration of excessive aluminum. In addition, our study has shown that considerable amounts of poorly ordered minerals like allophane and ferrihydrite were present in Jeju soils. The contents of $SiO_2$ were lower than those of other soil orders, but $A1_2O_3$ and $Fe_2O_3$ contents were higher. These results are some of the important chemical properties of Andisols. The contents of heavy metals were in the range of $84{\sim}198$ for Zn, $56{\sim}414$ for Ni, $38{\sim}150$ for Co, $132{\sim}1164\;mg\;kg^{-1}$ for Cr, which are higher than the worldwide values in most of the soils. Some soil samples contained relatively high levels of Cr exceeding 1000 mg/kg. Mean reduction capacity of the Jeju soils was $6.53\;mg\;L^{-1}$ reduced Cr(VI), 5.1 times higher than that of the non-volcanic ash soils from inland of Korea. The soil reduction capacity of the inland soils had a good correlation with total carbon content (R = 0.90). However, in spite of 20 times higher total carbon contents in the Jeju soils, there was a week negative correlation between the reduction capacity and the carbon content (R = -0.469), suggesting that the reduction capacity of Jeju soils is not mainly controlled by the carbon content and affected by other soil properties. Correlations of the reduction capacity with major elements showed that Al and Fe were closely connected with the reduction capacity in Jeju soil (R = 0.793; R = 0.626 respectively). Moreover, the amounts of Ni, Co and Cr had considerable correlations with the reduction capacity (R = 0.538; R = 0.647; R = 0.468 respectively). In particular, in relation to the behavior of redox-sensitive Cr, the oxidation of the trivalent chromium to mobile and toxic hexavalent chromium can be restricted by the high reduction capacity in Jeju soil. The factors controlling the reduction capacity in Jeju soils may have a close relation with the andic soil properties explained by the presence of considerable allophane and ferrihydrite in the soils.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.1B
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• pp.79-84
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• 2012

Nitrate is a common contaminant in groundwater aquifer. The present study investigates the performance of the bipolar zero valent iron (ZVI, $Fe^0$) packed bed electrolytic cell in removing nitrate in different operating conditions. The packing mixture consists of ZVI as electronically conducting material and silica sand as non-conducting material between main cathode and anode electrodes. In the continuous experiments for the simulated wastewater (contaminated groundwater, initial nitrate about 30 mg/L as N and electrical conductivity about 300 ${\mu}S/cm$), over 99% removal of nitrate was achieved in the applied voltage 600 V and at the flow rate of 20 mL/min. The optimum packing ratio (v/v) and flow rate were determined to be 1:1~2:1 (silica sand to ZVI), 30 mL/ min respectively. Effluent pH was proportional to nitrate influx concentration, and ammonia which is the final product of nitrate reduction was about 60% of nitrate influx. Magnetite was observed on the surface of the used ZVI as major oxidation product.

• Korean Journal of Microbiology
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• v.39 no.3
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• pp.175-180
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• 2003

Microbial Fe(III) reduction is an important factor for biogeochemical cycle in anaerobic environments, especially sediment of freshwater such as lakes, ponds and rivers. In addition, the Fe(III) reduction serves as a model for potential mechanisms for the oxidation of organic compounds and the reduction of toxic heavy metals, such as chrome or uranium. Shewanella putrefaciens DK-1 was a gram-negative, facultative anaerobic Fe(III) reducer and used ferric ion as a terminal electron acceptor for the oxidation of organic compounds to $CO_{2}$ or other oxidized metabolites. The ability of reducing activity and utilization of various electron acceptors and donors for S. putrefaciens DK-1 were investigated. S. putrefaciens DK-1 was capable of using a wide variety of electron acceptor, including $NO_{3}^{-}$, Fe(III), AQDS, and Mn(IV). However, its ability to utilize electron donors was limited. Lactate and formate were used as electron donors but acetate and toluene were not used. Fe(III) reduction of S. putrefaciens DK-l was inhibited by the presence of either $NO_{3}^{-}$ or $NO_{2}^{-}$. Further S. putrefaciens DK-1 used humic acid as an electron acceptor and humic acid was re-oxidized by nitrate. Environmental samples showing the Fe(III)-reducing activity were used to investigate effects of the limiting factors such as carbon, nitrogen and phosphorus on the Fe(III) reducing bacteria. The highest Fe (III) reducing activity was measured, when lactate as a carbon source and S. putrefaciens DK-1 as an Fe(III) reducer added in untreated sediment samples of Cheon-ho and Dae-ho reservoirs.