• Journal of IKEEE
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• v.27 no.4
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• pp.477-485
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• 2023

In this paper, the effect of AC ripple on the lifetime of lithium-ion batteries is experimentally analyzed. Bidirectional power conversion system(PCS) is used to increase the efficiency of energy storage systems (ESS). When connected to the grid, a current ripple with a frequency twice the grid frequency is applied to the battery due to its structure. Therefore, to analyze the effect of AC ripple on Li-ion battery aging, cycle life test are performed by applying charge/discharge profiles of DC current and DC+AC current ripple specifications. Based on the experimental results, direct current internal resistance (DCIR), incremental capacitance (IC), and surface temperature were analyzed. As a result, it is confirmed that AC ripple does not directly affect degradation and that battery degradation slows down after a certain cycle. These results can serve as a guideline for optimizing filters to reduce ripple on the battery side in applications where AC ripple occurs.

• Journal of Applied Biological Chemistry
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• v.66
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• pp.15-22
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• 2023

The aim of the present study was to evaluate the chemical composition and antioxidative activity of rhizome essential oil of Kaempferia parviflora Wall. ex Baker. The essential oil extracted by hydrodistillation was chemically profiled by GC/MS analysis. The antioxidative activity was determined and evaluated spectroscopically by the 2,2-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging assays. According to the results, the major essential oil components were camphene (18.03%), β-pinene (14.25%), a-pinene (12.38%), endo-borneol (10.23%), β-copaene (8.38%), and linalool (8.20%). K. parviflora rhizome oil possessed antioxidant potential, exhibiting DPPH and ABTS radical scavenging activities as high as 80.90 and 94.04%, respectively, at a concentration of 10 mg/mL. The corresponding IC₅₀ values were 0.451±0.051 and 0.527±0.022 mg/mL, respectively (IC₅₀ values for ascorbic acid, as the standard, were 0.209±0.016 and 0.245±0.022 mg/mL, respectively). The mycelium of F. oxysporum was distorted and collapsed when treated with 0.5 mg/mL of the EO of K. parviflora rhizome for 3 days treatment, which may provide an important information for exploring the metabolism of the fungicide K. parviflora rhizome and its derived compounds against F. oxysporum. This study provides the chemical properties of the essential oil of K. parviflora rhizome grown in Vietnam and their potential antioxidant and antifungal activities.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.11
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• pp.1186-1191
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• 2006

Removal efficiency of As(III) through oxidation and adsorption in column reactors was investigated at different ratios of manganese-coated sand(MCS) and iron-coated sand(ICS) : MCS-alone, ICS-alone and both of ICS and MCS. The breakthrough of arsenic immediately occurred from a column reactor with MCS-alone. However, most of the arsenic present in the effluent was identified as As(V) due to the oxidation of As(III) by MCS. While five-times delayed breakthrough of arsenic was observed from a column reactor with ICS-alone. At a complete breakthrough of arsenic, the removed As(III) was 36.1 mg with 1 kg ICS. To find an optimum ratio of ICS and MCS in the column packed with both ICS and MCS, the removal efficiency of As(III) was investigated at three different ratios of ICS/MCS with a fixed amount of ICS. The breakthrough time of arsenic was quite similar in the different ratios ICS/MCS. However, much slower breakthrough of arsenic was observed as the ratio of ICS/MCS decreased. As the ratio of ICS/MCS decreased the concentration of As(III) in the effluent decreased and then showed below 50 ppb at an equal amount of ICS and MCS, suggesting more efficient oxidation of As(III) by greater amount of MCS. When a complete breakthrough of arsenic occurred, the removed total arsenic with an equal amount of ICS and MCS was 68.5 mg with 1 kg of filter material.

• Journal of Life Science
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• v.19 no.11
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• pp.1598-1604
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• 2009

In order to determine chemical components of onion flesh and peel, general nutrients, vitamin C, and total flavonoids were measured. Onion peel showed less moisture (14.3%) and no vitamin C compared to onion flesh. Onion peel contained more amounts of total flavonoids compared to onion flesh. In addition, the inhibitory effects of solvent extracts from onion flesh and peel on $H_2O_$-induced oxidative stress and growth of cancer cell lines (AGS human gastric adenocarcinoma and HT-29 human colon cancer cells) were investigated. Acetone with methylene chloride (A+M) and methanol (MeOH) extracts from onion flesh and peel appeared to significantly reduce the levels of intracellular reactive oxygen species (ROS) (p<0.05) and a greater antioxidant effect was observed in onion peel. Among fractions, 85% aq. methanol showed a higher protective activity against oxidative stress in both flesh and peel and there was no effect in the water and hexane fractions. The growth of cancer cells exposed to medium containing extracts and fractions from onion flesh and peel was inhibited dose-dependently. The growth of AGS was inhibited more in both flesh and peel compared to HT-29, and onion peel was more effective than onion flesh. Among fractions, 85% aq. methanol showed the greatest effect on growth inhibition in both flesh and peel. $IC_{50}$ values of 85% aq. methanol fraction from onion flesh and peel on AGS were 0.04 and 0.03 mg/ml, respectively, while those on HT-29 were 0.23 and 0.04 mg/ml. From our results, 85% aq. methanol fraction had an inhibitory effect against oxidative stress and growth of cancer cells, suggesting that it may contain biological active compounds.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.34 no.3
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• pp.189-200
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• 2008

In this study, the antioxidative effects, inhibitory effects on elastase, and components of Quercus glauca extracts were investigated. The free radical (1,1-diphenyl-2-picrylhydrazyl, DPPH) scavenging activity $(FSC_{50})$ of extract I fractions of Quercus glauca leaf was in the order: 50% ethanol extract $(12.45{\mu}g/mL)$ < ethyl acetate fraction $(10.47{\mu}g/mL)$ < deglycosylated flavonoid aglycone fraction $(8.57{\mu}g/mL)$. Reactive oxygen species (ROS) scavenging activities $(OSC_{50})$ of some Quercus glauca leaf extracts on ROS generated in $Fe^{3+}-EDTA/H_2O_2$ system were investigated using the luminol-dependent chemiluminescence assay. The order of ROS scavenging activity was 50% ethanol extract $(OSC_{50},\;4.2{\mu}g/mL)$ < deglycosylated flavonoid aglycone fraction $(1.58{\mu}ug/mL)$ < ethyl acetate fraction $(0.66{\mu}g/mL)$. Ethyl acetate fraction showed the most prominent scavenging activity. The protective effects of extract / fractions of Quercus glauca leaf on the rose-bengal sensitized photohemolysis of human erythrocytes were investigated. The Quercus glauca leaf extracts suppressed photohemolysis in a dose dependent manner, particularly deglycosylated flavonoid aglycone fraction exhibited the most prominent celluar protective effect $({\tau}_{50}$, 398.67 min at $50{\mu}g/mL$). Aglycone fractions obtained from the deglycosylation reaction of ethyl acetate fraction among the Quercus glauca leaf extracts, showed 2 bands in TLC and 2 peaks in HPLC experiments (360 nm) as well. Two components were identified as quercetin (55.77%), and kaempferol (44.23 %). TLC chromatogram of ethyl acetate fraction of Quercus glauca leaf extracts revealed 6 bands $(QG1{\sim}QG6)$, Among them, isoquercitrin (QG3), hyperin (QG4), and rutin (QG6) were identified. The inhibitory effect of aglycone fraction on tyrosinase $(IC_{50},\;73.5{\mu}g/mL)$ and elastase $(IC_{50},\;16.2{\mu}g/mL)$ was high. These results indicate that extract / fractions of Quercus glauca can function as antioxidants in biological systems, particularly skin exposed to UV radiation by scavenging $^1O_2$ and other ROS, and protect cellular membranes against ROS. And component analysis of Quercus glauca leaf extract and inhibitory activity on tyeisinase and elastase of the aglycone fraction could be applicable to new functional cosmetics.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.1
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• pp.195-201
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• 2014

In this study, face recognition system was designed based on polynomial Radial Basis Function Neural Networks(pRBFNNs) pattern classifier using 2-directional 2-dimensional principal component analysis algorithm. Existing one dimensional PCA leads to the reduction of dimension of image expressed by the multiplication of rows and columns. However $(2D)^2PCA$(2-Directional 2-Dimensional Principal Components Analysis) is conducted to reduce dimension to each row and column of image. and then the proposed intelligent pattern classifier evaluates performance using reduced images. The proposed pRBFNNs consist of three functional modules such as the condition part, the conclusion part, and the inference part. In the condition part of fuzzy rules, input space is partitioned with the aid of fuzzy c-means clustering. In the conclusion part of rules. the connection weight of RBFNNs is represented as the linear type of polynomial. The essential design parameters (including the number of inputs and fuzzification coefficient) of the networks are optimized by means of Differential Evolution. Using Yale and AT&T dataset widely used in face recognition, the recognition rate is obtained and evaluated. Additionally IC&CI Lab dataset is experimented with for performance evaluation.

• Applied Biological Chemistry
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• v.49 no.1
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• pp.77-81
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• 2006

This study was carried out to investigate the chemical components, and antioxidative and $anti-{\alpha}-glucosidase$ activities of Equisetum arvense extracts. In Equisetum arvense extracts were composed of 53.20% of crude fiber, 20.42% of crude ash, 15.32% of crude protein and 2.21% of crude fat. Potassium was the most predominant mineral and followed by phosphorus, calcium, magnesium, and sodium. The contents of the unsaturated fatty acids, such as linolenic acid, linoleic acid, and palmitic acid, were higher than those of saturated fatty acids. Seventy percent ethanol extract exhibited antioxidative activity with $IC_{50}$ of $168.1\;{\mu}g/ml$. The Seventy percent methanol extract showed higher ${\alpha}-glucosidase$ inhibitory activity than other solvent extracts.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.33 no.3
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• pp.139-144
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• 2007

In the previous study, we reported the antioxidative activity of Equisetum arvense extracts. In this study, its inhibitory effect on elastase and components were investigated. Aglycone fractions obtained from the deglycosylation reaction of ethylacetate fraction among the Equisetum arvense extracts, showed 4 bands and 4 peaks in TLC and HPLC experiments, respectively. Four components were identified as luteolin(composition ratio, 19.12%), quercetin(12.87), apigenin(15.81) and kaempferol(52.20). TLC chromatogram of ethylacetate fraction of Equisetum arvense extract revealed 7 bands and HPLC chromatogram showed 8 peaks, which were identified as kaempferol-3,7-O-diglucoside(composition ratio, 15.74%), luteolin-5-O-glucoside(galuteolin, 11.91), apigenin-5-O-glucoside(12.91), kaempferol-3-O-glucoside(astragalin, 27.94), quercetin-glycoside(10.81, structure was not determined), kaempferol-glycoside (12.33, structure was not determined), luteolin(3.72) and apigenin(4.62) in the order of elution time. The inhibitory effect of aglycone fraction on elastase($IC_{50}$, $9.8{\mu}g/mL$) was very high. But ethylacetate fraction(flavonoid glycosides) rarely exhibited the inhibitory activity on elastase. Combined with the previous results of the antioxidative activity of Equisetum arvense extracts, it is concluded that the inhibitory activity on elastase of the aglycone fraction could be applicable to new functional cosmetics for smoothing wrinkles.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.43 no.1
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• pp.69-78
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• 2017

Hwangryunhaedoktang (HHT) has been traditionally used as a preventive and therapeutic medicine to treat enervation and diverse chronic diseases. This study was designed to compare the antioxidant, anti-wrinkle and whitening effects of HHT extract and its fermented extract by Leuconostoc mesenteroides (FHHT). FHHT was prepared by inoculation of L. mesenteroides after the extraction procedure with 70% ethanol. HHT and FHHT was investigated via high-performance liquid chromatography (HPLC). Simultaneous qualitative analysis of two bioacitive components, berberine and palmatine. was achieved by comparing their retention times ($t_R$) and UV spectra with those of the standard components. Cell viability test results indicated that both HHT and FHHT were non-toxic. In DPPH radical scavenging ability, $SC_{50}$ values of the FHHT was $68.85{\mu}g/mL$, which is more effective than HHT. Moreover, FHHT showed higher expression in production of procollagen type I than HHT. In nontoxic concentration range, FHHT showed strong melanin production inhibitory effect in ${\alpha}-melanocyte$ stimulating hormone (${\alpha}-MSH$)-stimulated B16F10 cell ($IC_{50}=9.82{\mu}g/mL$). These results suggested that fermented extracts of hwangryunhaedoktang had considerable potential as a cosmetics ingredient with an antioxidant and anti-wrinkle and whitening effects.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.43 no.3
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• pp.201-210
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• 2017

Scutellariae baicalensis (S. baicalensis) has been traditionally used for anti-inflammatory effect. This study was designed to compare the antioxidant and whitening effects of S. baicalensis extract and its fermented extract by Leuconostoc mesenteroides (L. mesenteroides). Fermented extract of S. baicalenins was prepared by inoculation of L. mesenteroides after the extraction procedure with 70% ethanol. S. baicalensis extract and its fermented extract was investigated via high-performance liquid chromatography (HPLC). Simultaneous qualitative analysis of two bioactive components; baicalin and baicalein was achieved by comparing their retention times ($t_R$) and UV spectra with those of the standard components. Cell viability test results indicated that both S. baicalensis extract and its fermented extract were non-toxicity. In DPPH radical scavenging ability, $SC_{50}$ values of the fermented extract was $34.43{\mu}g/mL$ as a result of more effective than S. baicalensis extract. In nontoxic concentration rage, fermented extract of S. baicalensis showed strong melanin production inhibitory effect in ${\alpha}$-melanocyte stimulating hormone (MSH)-stimulated B16F10 cell ($IC_{50}=68.17{\mu}g/mL$). These results suggested that fermented extracts of S. baicalensis has considerable potential as a cosmetics ingredient with an antioxidant and anti-wrinkle and whitening effects.