• Journal of the Korean Society of Safety
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• v.13 no.3
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• pp.96-101
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• 1998

In order to study the change in mechanical properties and anti-flammablilty of ethylene-ethylacrylate copolymer(EEA) very low density polyethylene(VLDPE) compound that could be used as communication cable sheath using $Mg(OH)_2$ as a non-toxic flame retardant, 100, 125, and 150phr $Mg(OH)_2$ were added to 100 parts of EEA-VLDPE compound, 100 EEA : 0 VLDPE, 50 EEA : 50 VLDPE, and 0 EEA : 100 VLDPE, respectively. $Mg(OH)_2$ was a good non-toxic flame retardant for communication cable sheath and anti-flammability increased with the amount of $Mg(OH)_2$ in compound. The mechanical properties-MI, Ts, and Eb-decreased with increasing in the mixing ratio of EEA but oxygen index(OI) increased with increasing in the amount of EEA. The best composition of $Mg(OH)_2$ in this study was 150phr to 50 EEA : 50 VLDPE compound for the anti-flammability.

• The Korean Journal of Ecology
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• v.26 no.1
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• pp.5-12
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• 2003

Seed germination rate and seedling growth were measured on 6 different species(Phytolacca americana, Eupatorium rugosum, Rumex acetocella, Echinochloa crusgalli, Cassia mimosoides var. nomame, Setaria viridis) treated with leaf extract of E. rugosum. Total phenolic compound and heavy metal were analyzed on leaf and soil with and without E. rugosum. The growth of P. americana seedlings were stimulated by 10% and 25% of E. rugosum water extract treatment. The content of total phenolic compounds in soil was lower than that of leaf extract, and 25% was confirmed as threshold concentration in natural systems because the total phenolic compounds were not significantly different between the control soils and the soil treated with 10%, and 25% extract. Total phenolic compound concentrations of the leaf extracts were highest (1.66 mg/l) with E. rugosum grown under the Quercus forest canopy and lowest (1.09 mg/l) for the plant grown in the mixed forest edge. Leaf extracts of plants selected in different sampling sites (Forest interior, Forest edge, under Pinus Canopy and Quercus Canopy) were significant, while soil extracts were not. Seed germination of R. acetocella and S. viridis were significantly inhibited at over 50% concentrations of E. rugosum, but C. mimosoides var. nomame was not affected at any concentration. The radicle and shoot growth of the native species group were reduced two times more than those of the exotic species group by the treatment of extracts. Especially, the seed germination percentage and dry weight of E. rugosum were greater than those of the control group by treatments with extracts of 10% and 25%. Analysis of aqueous extracts from E. rugosum by HPLC identified 6 phenolic compounds: caffeic acid (460.9 mg/l), benzoic acid (109.7 mg/l), protocatechuic acid (7.3 mg/l), ρ-hydroquinone (6.0 mg/l), cinnamic acid (2.7 mg/l) and hydroquinone (0.23 mg/l). The seed germination of P. americana was also inhibited dramatically by protocatechuic acid and cinnamic acid even though the content of caffeic acid (460.9 mg/l) was the highest among analyzed phenolic compounds. The heavy metal content of soil without A. altissima was higher than that of soil with E. rugosum. Particularly, Al, Fe and Mn was considerably high and most of the heavy metal were accumulated in leaves where a high level of total phenolic compounds was found.

• Environmental Engineering Research
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• v.16 no.3
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• pp.149-157
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• 2011

Nanofiltration (NF) experiments were conducted to investigate fouling of Al-hydroxide precipitate and the influence of organic compound, inorganic compound, and their combination, i.e., multiple foulants. $CaCl_2$ and $MgSO_4$ were employed as surrogates of inorganic compounds while humic acid was used as surrogate of organic compound. The flux attained from NF experiments was fitted with the mathematical fouling model to evaluate the potential fouling mechanisms. Al-hydroxide fouling with a cake formation mechanism had little effect on the NF membrane fouling regardless of the Al concentration. The NF fouling by Al-hydroxide precipitate was deteriorated in presence of inorganic matter. The effect of Mg was more critical in increasing the fouling than Ca. This is because the Mg ions enhanced the resistances of the cake layer accumulated by the Al-hydroxide precipitate on the membrane surfaces. However, the fouling with Mg was dramatically mitigated by adding humic acid. It is interesting to observe that the removal of the conductivity was enhanced to 61.2% in presence of Mg and humic acid from 30.9% with Al-hydroxide alone. The influence of dissolved matter (i.e., colloids) was more negative than particulate matter on the NF fouling for Al-hydroxide precipitate in presence of inorganic and organic matter.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.1
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• pp.144-147
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• 1997

For the investigation of antitumor agents, two kinds of sesquiterpene lactones were isolated and purified from Chrysanthemum boreale M. and designated as Compound I and ]U . And then in vivo antitumor test of the sesquiterpene lactones was carried out against ICR mice. In vivo test against Sarcoma180 implanted ICR mice, life prolongation effects of Compound I and II were showed as 143% and 134% at the dose of 10mg/kg, respectively. Besides, at the tested group mixed Compound I and II each 1mg/kg was showed rather high life prolongation effect as 158%.

• Journal of the Korean Applied Science and Technology
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• v.38 no.6
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• pp.1466-1475
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• 2021

Compound K (20-O-β-(_D-glucopyranosyl)-20(S)-protopanaxadiol) is an active ingredient of ginsenosides. Compound K has been known to produce from biotransformation by β-glucosidase action of human intestinal microbes after oral admistration of ginseng. We have investigated the cytotoxicity of compound K obtained from bio-converted ginseng extract. As a result, compound K showed no significant cytotoxicity in the concentration of 0.001 to 1 ㎍/mL and inhibited the production of TNF-α, MCP-1, IL-6 and NO in RAW 264.7 cells induced by LPS inflamation. In the same concentration, HaCaT cells induced by inflammation with TNF-α and IFN-γ decreased IL-8 production due to compound K treatment. In the brine shrimp lethality assay, the LC₅₀ of compound K was 0.37 mg/mL indicating some toxicity, but the bioconverted product containing 35% compound K showed relatively low toxicity with an LC₅₀ of 0.87 mg/mL. These results suggest that the compound K enriched extract is a potential functional material for acne relief cosmetic products.

• Preventive Nutrition and Food Science
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• v.14 no.3
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• pp.173-178
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• 2009

This study was conducted to determine if supplementation with a compound composed of caffeine (50 mg), capsaicin (75 mg), sesamine (30 mg), L-carnitine (300 mg), banaba (50 mg) and lotus (10 mg) enhanced human autonomic nervous activities (ANS) associated with thermogenic sympathetic activity and fat utilization. Ten healthy college males (21.2$\pm$1.0 yr) volunteered for this experiment. Autonomic nervous activities associated with energy metabolism were examined at 30 min intervals for a total of 120-min while at rest and every 5-min during exercise at 50% of the ventilation threshold before and after intake of the compound or placebo with 100 ml of water for 10 days. In addition, heart rate variability power spectral analysis was used to assess human autonomic nervous activities. The results indicated that there were no significant differences in heart rate during rest and exercise among trials. Furthermore, the autonomic nervous activity tended to increase after 10-days of consumption of the test compounds during the experimental period, but the differences did not reach statistical significance. However, before and after the compound test trial there was a significantly higher respiratory gas exchange ratio (rest 0: 0.83$\pm$0.01 vs. rest 3: 0.89$\pm$0.02, p<0.05), carbohydrate oxidation (CHO) rate (rest 0: 44.57$\pm$5.83 vs. rest 2: 63.86$\pm$5.91%, p<0.05) and a lower fat oxidation rate (rest 0: 55.43$\pm$5.83 vs. rest 2: 36.14$\pm$5.91%, p<0.05. In conclusion, the results of the present study suggested that the compound composed of caffeine, capsaicin, sesamine, L-carnitine, banaba and lotus components that was evaluated in this study did not induce a significant increase in human autonomic nervous activities or lipolysis, even though the individual components have been reported to induce increased fat oxidation.

• Journal of Korea Foundry Society
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• v.39 no.3
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• pp.33-43
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• 2019

In this study, the effects of Zn additions on the mechanical properties of Al-Si-Mg-Cu alloys were investigated by increasing the amount of Zn up to 8wt.%. As the Zn content was increased up to 6 wt.%, the yield strength and elongation changed linearly without any significant changes in the size and shape of the main reinforcement phase. However, it was confirmed by SEM observation that the Mg-Zn phase formed between the reinforcement phases when the amount of Zn added exceeded 7wt.%. A Mg-Zn intermetallic compound formed between the $Mg_2Si$ phase, becoming a crack initiation point under stress. Thus, the formation of the Mg-Zn phase may cause a sharp decrease in the elongation when Zn at levels exceeding 7 wt.%. It was also found that the matrix became more brittle with increasing the Zn content. From these results, it can be concluded that the formation of the Mg-Zn intermetallic compound and the brittle characteristics of the matrix are the main causes of the remarkable changes in the mechanical properties of this alloy system

• Journal of Environmental Health Sciences
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• v.21 no.2
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• pp.27-35
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• 1995

In order to investigate acute toxicity and bioconcentration of heavy metals for a freshwater fish, the fish used in this experiment was goldfish, Carassius auratus. Each ten goldfish was accommonidated in a water and was treated with different concentration of Pb and Cu compound. The 24 $hr-LC_{50}$ was obtained by plotting on the log-normal distribution graph. Furthermore, the combined effect of Pb and Cu was also investigated the fish was treated with Pb or Cu compound only, and Pb and Cu compound together, respectively. These results were summarized as follows: 1. The 24 $hr-LC_{50}'s$ of Pb and Cu were 7.48 mg/l and 0.666 mg/l, respectively. 2. When single or/and combined treatment with Pb(7.0 mg/l) or/and Cu(0.6 mg/l) to Carassius auratus for 24 hours were performed, there was significant difference between the single or/and the combined treatment in their bioaccumulated Cu concentrations. Cu concentrations in goldfish were higher in the combined treatment than in the single treatment. 3. When Carassius auratus was exposed to 0.748 mg/l (1/10 of 24 $hr-LC_{50}$) and 1.496 mg/l of Pb (1/5 of 24 $hr-LC_{50}$) for 7 days, the bioconcentration factors (BCF) were 79.14 and 100.11 for Pb, respectively. The BCF of Pb was obtained as a linearity according to the concentration and exposure time as follows log BCF=1.014 log $P\cdot T$+1.011 ($r^2$=0.9041) where, P: pollutant concentration(mg/l) T: exposure time(day) 4. When Carassius auratus was pxposed to 0.0666 mg/l (1/10 of 24 $hr-LC_{50}$) and 0.1332 mg/l of Cu (1/5 of 24 $hr-LC_{50}$) for 7 days, the bioconcentration factors (BCF) were 55.42 and 63.24 for Cu respectively. The BCF of Cu was obtained as a linearity according to the concentration and exposure time as follows log BCF=0.571 log $P\cdot T$+1.823 ($r^2$=0.8974) where, P: polutant concentration(mg/l) T: exposure time(day)

• Korean Journal of Soil Science and Fertilizer
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• v.32 no.4
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• pp.440-445
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• 1999

In order to investigate the change of physiological active compounds in buckwheat with soil chemical properties and soil conditioners, we cultured buckwheat at an experimental open field station, Chonnam Provincial Agicultual Reserch and Extension Service. Fatty acids, phenolic compounds and tyrosinase inhibitory activity (TIA) from buckwheat grains and plants were analyzed. The contents of fatty acids in buckwheat plants was less than that of buckwheat grain. The fatty acids of buckwheat plants and grains were composed of saturated and unsaturated fatty acids. The contents of unsaturated fatty acids were more than saturated fatty acids. The phenolic compounds in buckwheat were from $682.6mg\;kg^{-1}$ to $1822mg\;kg^{-1}$. The phenolic compounds in buckwheat with addition of applied lime were $1822mg\;kg^{-1}$. It was higher than any other plot. The tyrosinase inhibitory activity (TIA) of sediment c in buckwheat grain with addition of applied lime was 92.8%. It was more than that of sediment a, b or compound A, B, C within the same treatment. But the TIA of compound C in buckwheat with application of borax was 81.0%. It was highest of all sediments and compounds within the same treatment.

• Journal of Microbiology and Biotechnology
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• v.30 no.10
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• pp.1559-1566
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• 2020

Compound K (C-K) is one of the most pharmaceutically effective ginsenosides, but it is absent in natural ginseng. However, C-K can be obtained through the hydrolysis of protopanaxadiol-type ginsenosides (PPDGs) in natural ginseng. The aim of this study was to obtain the high concentration of food-available C-K using PPDGs in Korean ginseng extract by an extracellular enzyme from Aspergillus niger KACC 46495. A. niger was cultivated in the culture medium containing the inducer carboxymethyl cellulose (CMC) for 6 days. The extracellular enzyme extracted from A. niger was prepared from the culture broth by filtration, ammonium sulfate, and dialysis. The extracellular enzyme was used for C-K production using PPDGs. The glycoside-hydrolyzing pathways for converting PPDGs into C-K by the extracellular enzyme were Rb1 → Rd → F2 → C-K, Rb2 → Rd or compound O → F2 or compound Y → C-K, and Rc → Rd or compound Mc1 → F2 or compound Mc → C-K. The extracellular enzyme from A. niger at 8.0 mg/ml, which was obtained by the induction of CMC during the cultivation, converted 6.0 mg/ml (5.6 mM) PPDGs in Korean ginseng extract into 2.8 mg/ml (4.5 mM) food-available C-K in 9 h, with a productivity of 313 mg/l/h and a molar conversion of 80%. To the best of our knowledge, the productivity and concentration of C-K of the extracellular enzyme are the highest among those by crude enzymes from wild-type microorganisms.