• Korean Journal of Soil Science and Fertilizer
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• v.46 no.6
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• pp.659-664
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• 2013

The aim of this study is to determine the drought stress index through photochemical analysis in red pepper (Capsiumannuum L.). The photochemical interpretation was performed in the basis of the relation between Kautsky effect and Photosystem II (PSII) following the measurement of chlorophyll, pheophytin contents, and $CO_2$ assimilation in drought stressed 5-week-old red pepper plants. The $CO_2$ assimilation rate was severely lowered with almost 77% reduction of chlorophyll and pheophytin contents at four days after non-irrigation. It was clearly observed that the chlorophyll fluorescence intensity rose from a minimum level (the O level), in less than one second, to a maximum level (the P-level) via two intermediate steps labeled J and I (OJIP process). Drought factor index (DFI) was also calculated using measured OJIP parameters. The DFI was -0.22, meaning not only the initial inhibition of PSII but also sequential inhibition of PSI. In real, most of all photochemical parameters such as quantum yield of the electron transport flux from Quinone A ($Q_A$) to Quinone B ($Q_B$), quantum yield of the electron transport flux until the PSI electron acceptors, quantum yield of the electron transport flux until the PSI electron acceptors, average absorbed photon flux per PSII reaction center, and electron transport flux until PSI acceptors per cross section were profoundly reduced except number of QA reducing reaction centers (RCs) per PSII antenna chlorophyll (RC/ABS). It was illuminated that at least 6 parameters related with quantum yield/efficiency and specific energy fluxes (per active PSII RC) could be applied to be used as the drought stress index. Furthermore, in the combination of parameters, driving forces (DF) for photochemical activity could be deduced from the performance index (PI) for energy conservation from photons absorbed by PSII antenna until the reduction of PSI acceptors. In conclusion, photochemical responses and their related parameters can be used as physiological DFI.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.6
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• pp.662-671
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• 2020

Recently, for the purposes of reducing carbon dioxide(CO₂) emissions in the island area, countermeasures to decrease the operation rate of diesel generator(DG) and to increase one of renewable energy sources(RES) is being studied. In particular, the demonstration and installation of stand-alone micro-grid(MG) system which is composed of DG, RES and energy storage system(ESS) has been implemented in some island areas such as Gapa-do, Gasa-do and Ulleung-do island. However, many power quality(PQ) problems may be occurred due to an intermittent output of RES including photovoltaic(PV) system and wind power(WP) system in a normal operating of constant voltage & constant frequency(CVCF) inverter-based MG system. Therefore, this paper presents a modeling of the 30kW scale MG system using PSCAD/EMTDC, and also implements a 30kW scale CVCF inverter-based MG system as test devices to analyze normal operating characteristics of MG system. From the simulation and test results, it is confirmed that the proposed methods are useful and practical tools to improve PQ problems such as under-voltage, over-voltage and unbalanced load in CVCF inverter-based MG system.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.12
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• pp.1740-1746
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• 2016

In this study, we investigated the nutritional and functional constituents as well as quality characteristics and antioxidant activity of Korean cultivated wild ginseng (KG). The chemical compositions and amino acid content of KG were 7.56% water, 73.01% carbohydrates, 12.58% protein, 1.99% lipids, and 5.54% ash as well as 16.17 mg/g of amino acids, respectively. The major ginsenoside and minor ginsenoside contents of KG were 15.94 mg/g and 0.04 mg/g, respectively. The total polyphenol and flavonoid contents of KGE (Korean cultivated wild ginseng with 70% ethanol extract) were 8.93 mg GAE/g and 3.96 mg RHE/g, respectively. KGE also showed higher antioxidant activity than the other extracts (KGW, Korean cultivated wild ginseng with water extract) with regard to DPPH and ABTS radical scavenging activities (57.75% and 70.73%, respectively), nitrite oxide scavenging activity (44.01%), SOD-like activity (78.05%), reducing power activity ($1.08OD_{700nm}$), and ferrous ion-chelating activity (65.33%). Additionally, KGE had higher elastase, collagenase, and tyrosinase inhibition activities than KGW. These results suggest that KGE can be used as a bioactive and functional material in the food industry.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.16 no.3
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• pp.389-396
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• 2018

The Kori-1 Nuclear Power Plant (NPP), WH 2-Loop Pressurized Water Reactor (PWR) operated for approximately 40 years in Korea, was permanently ceased on June 18, 2017. To reduce worker exposure to radiation by reducing the dose rate in the system before starting main decommissioning activities, the permanently ceased Kori-1 NPP will be subjected to full system decontamination. Generally, the range of system decontamination includes Reactor Pressure Vessels (RPV), Pressurizer (PZR), Steam Generators (SG), Chemical & Volume Control System (CVCS), Residual Heat Removal System (RHRS), and Reactor Coolant System (RCS) piping. In order to decontaminate these systems and equipment in an effective manner, it is necessary to evaluate the influence of the flow characteristics in the RCS during the decontamination period. There are various methods of providing circulating flow rate to the system decontamination. In this paper, the flow characteristics in Kori-1 NPP reactor coolant according to RHR pump operation were evaluated. The evaluation results showed that system decontamination using an RHR pump was not effective at decontamination due first to impurities deposited in piping and equipment, and second to the extreme flow unbalance in the RCS caused deposition of impurities.

• Korean Journal of Microbiology
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• v.52 no.4
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• pp.421-427
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• 2016

Acne is known as the most common skin disease. It commonly occurs during adolescents, but it is also present in children and adults because of air pollution, drug abuse and so on. In addition to the hormonal, genetic and environmental factors, Propionibacterium acnes (P. acnes) have also critical roles in outbreak of acne by inducing inflammatory mediators. Increase of sebum production provides an ideal environment for P. acnes that induce inflammation on the skin by activation of monocytic cells and stimulation of inflammatory cytokines. In this study, natural extracts were investigated for anti-inflammatory effects against inflammatory acne by P. acnes infection in terms of reducing cytokine production. Eucalyptus globulus extracts effectively suppressed mRNA synthesis of inflammatory mediators such as $TNF-{\alpha}$, $IL-1{\beta}$, IL-2, and NLRP3 in P. acnes-activated macrophages. Moreover, Eucalyptus globulus extracts inhibit activation of transcription factors, $NF-{\kappa}B$ and NFAT, which are known as key regulators of inflammatory cytokine production. This study suggests the potential of using Eucalyptus globulus extracts as alternative agents for the treatment of acne.

• Food Science and Preservation
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• v.23 no.2
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• pp.252-258
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• 2016

This study was conducted to investigate the antioxidant activities and physiological properties of Euphorbia humifusa extracts prepared using three different solvents (water, ethanol, and methanol). The highest total polyphenol content (293.25 mg/100 g) and total flavonoid content (21.05 mg/100 g) were observed in the methanol extract. The content of substances related to proanthocyanidin were highest in the water extract (8.42 mg/100 g), followed by methanol (5.70 mg/100 g) and ethanol (5.39 mg/100 g) extracts. The DPPH and ABTS radical scavenging activities of the methanol extract were 91.72% and 85.83%, respectively, at 50 mg% concentrations, which were higher than those of the other extracts. The extract reducing power decreased in the following order: ethanol > methanol > water. The methanol extract had relatively high antioxidant activity. The ${\alpha}-glucosidase$ and xanthine oxidase inhibitory activities of the methanol extract at a concentration of 10 mg% were somewhat higher than the other extracts. HMG-CoA reductase inhibitory activity in the water extract was slightly higher than in the methanol and water extracts. These results indicated that Euphorbia humifusa extracts were a high-value food ingredient due to their antioxidant activities and nutritional value.

• Food Science and Preservation
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• v.17 no.1
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• pp.145-150
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• 2010

Ultra-fine powder (FA) extracts from persimmon were investigated as potential food materials in industrial processes because such extracts have various useful biological activities. We examined the antioxidant and anti-allergic activity of FA extracts using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and ferric reducing activity of plasma (FRAP) models, and by measuring interleukin 4 (IL-4) expression in spleen cells and in an atopy animal model. FA extracts were prepared using solvents including distilled water and 50% (v/v) acetone. The results showed that FA extracts had potent DPPH and FRAP activities, decreased IL-4 expression in spleen cells, and inhibited ear thickness and inflammation in a mouse animal model. The data indicate that a FA extract could be used as an antioxidant and/or anti-inflammation agent, and in industrial food preparation processes.

• Journal of the korean academy of Pediatric Dentistry
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• v.44 no.3
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• pp.358-364
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• 2017

For the purpose of convenience and reducing time, newer bonding agents have been developed for composite resin restoration. Recently developed one bottle bonding system including etching, primer and adhesive can make procedures simpler and less technique-sensitive than old generation adhesives. The aim of this study was comparing the shear bond strength of new dentin bonding agents to the 5th generation bonding agent which had an etching step. 78 premolar teeth were randomly divided into three groups which were treated with $Tetric^{(R)}$ N-Bond Universal (Ivoclar Vivadent, Liechtenstein), $GC^{(R)}$ G-Premio BOND (GC Co., Japan) without additional etching step and $3M^{TM}$ Single Bond2 (3M ESPE, USA) with an etching step following manufacturer's instructions. $Filtek^{TM}$ Z-350 (3M ESPE, USA) composite resin was applied and light cured over bonding agents. For shear bond strength evaluation, universal testing machine was used with a wedge technique. As a result, shear bond strength of one step bonding agents was lower than two step bonding agent and there were statistically significant differences between them (p < 0.05). In addition, within the result of two new bonding agents, $Tetric^{(R)}$ N-Bond Universal showed significantly higher shear bond strength than $GC^{(R)}$ G-Premio BOND (p < 0.05).

• Journal of Mushroom
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• v.10 no.1
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• pp.3-8
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• 2012

In this study, to produce Flammulina velutipes mushroom liquid spawn efficiently and effectively the effects of explosive aeration (supplying air with tiny bubbles) of the liquid culture medium on carbon dioxide concentration and residual sugar content in the medium on carbon dioxide concentration and residual sugar contentin the medium were measured. Carbon dioxide concentrations were measured at the outlet of the incubator. On the third day the explosive aeration greatly increased mycelial growth of the liquid spawn, and carbon dioxide concentration also greatly increased but decreased after 5 days. Free sugar contents in the liquid culture consistantly decreased up to 7 days and thereafter was not detected. The weight of the mycelia were maintained similar levels after 3 days. Total nitrogen content in the liquid medium constantly decreased during the 11days of explosive aeration. The content of free sugars in 7 days of culture was the lowest level, thus the inoculum incubated for 6~7 days was thought to be the most effective. Carbon dioxide concentration measurement at the outlet of the container during the liquid spawn incubation required low cost but was efficient to estimate the degree of mycelial growth to be used as a simple indicator.

• Korean journal of food and cookery science
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• v.21 no.5
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• pp.733-741
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• 2005

Waxy barley flour was fermented by two kinds of starter cultures; L. plantarum and L. brevis, alone or in combination and the effect was evaluated on waxy barley and wheat composite bread quality. In all three barley sourdoughs, fermentation decreased the pH, total sugar and reducing sugar, and increased lactic acid bacteria cell numbers. However yeasts (S. cerevisiae) were reduced. There was significant difference in physicochemical characteristics between the reference(composite barley dough containing improvement agent) and the barley sourdoughs (p <0.05). Barley sourdough fermented by L. plantarum showed more desirable farinogram properties of peak time, stability and elasticity than that of the reference. The rheofermentometer data for L. brevis produced the most $CO_2$ release curve, whereas L. plantarum held maximum $CO_2$ retention differed significantly from that of the breads made with barley sourdoughs fermented with the respectives starter cultures (p < 0.05). Barley sourdough bread fermented with L. plantarum resulted in better bread quality than the reference bread. The positive effect of fermentation with L. plantarum on bread quality was evident when comparing the well developed protein-starch matrix structure of the bread baked with barley sourdough with the reference bread.