• Applied Chemistry for Engineering
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• v.28 no.5
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• pp.581-586
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• 2017

In this study, in order to find the feasibility of thermophilic biological pre-treatment for the co-digestion of food wastewater and sewage sludge, digestion efficiency of the combined thermophilic aerobic and mesophilic anaerobic process and its effect on methane production were investigated. Also, a lab-scale co-digestion process was operated to observe parameter changes according to the increase of organic loading rates using different dilution ratios of distilled water and food wastewater (1/3 [Run I], 2/3 [Run II] in addition to using the raw food wastewater [Run III]). The results indicated that co-digestion process maintained quite stable and constant pH during entire experiments. With regard to VS removal, the higher removal was observed in the combined process and the removal efficiency was 52.24% (Run I), 66.59% (Run II) and 72.53 (Run III), respectively. In addition, the combined process showed about an 1.6-fold improved methane production rate and significantly higher methane yield than that of using single anaerobic digestion process.

• KSBB Journal
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• v.20 no.3
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• pp.210-214
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• 2005

The characteristics of sesame oil containing one of natural antioxidant, ' $\gamma$-tocopherol', were studied with the supercritical $CO_2$ extraction. Although $\gamma$-tocopherol has a lower vitamin E value in biological systems than $\alpha$-tocopherol, it is a more potent antioxidant with in oils. For the research of various factors influence to the $\gamma$-tocopherol contents increment, we have checked roasting time and temperature, as well as pressure, temperature and flow rate of supercritical fluid. As a result, we found that the $\gamma$-tocopherol content was maintained constant under the condition of roasting temperature over $200^{\circ}C$. With the longer roasting time, $\gamma$-tocopherol content was increased. Except 250 bar, the $\gamma$-tocopherol content was maintained constant under the condition of the various pressure of supercritical fluid. But $\gamma$-tocopherol content was increased with lower flow rate of supercritical fluid from 1 $m{\ell}$/L to 3 $m{\ell}$/L. When the extraction performance with the supercritical fluid was compared to the conventional compressed extraction, $\gamma$-tocopherol content was increased up to 1.6 times.

• Korean Journal of Environment and Ecology
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• v.31 no.5
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• pp.461-471
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• 2017

Population genetic studies of 10 groups of Iksookimia pacifica were conducted to investigate the genetic diversity and population genetic structure across its known range in South Korea. Population DNA sequences of one mitochondrial gene (mtCOI) and three nuclear genes (IRBP, EGR2B, RAG1) were examined in samples collected from ten streams that flow into the East Sea. Both mitochondrial and nuclear sequences exhibited significant differentiation among populations except a few cases. The Bayesian analysis of the multi-locus genotypes inferred from the DNA sequences of nuclear genes clustered the individual fish largely into two geographical groups: a northern group (from Baebong stream to Cheonjin stream) and a southern group (Yangyangnamdae stream to Gangneungnamdae stream). Given that the streams flowing into the East Sea are geographically isolated water systems, such separation of genotypes can be interpreted by the geographical separation of common ancestors into north and south that had colonized South Korea. Since the initial geographical separation of the ancestral population by north and south, the ancestral groups seem to have experienced further differentiation into the current genetic clusters through the physical isolation of streams by the East Sea in each region. It is notable that many individuals in the Jasan stream formed a genetic cluster with those of Yangyangnamdae and Gangneungnamdae streams which are distant from each other. In addition, mitochondrial gene showed low genetic differentiation between some neighboring populations and very low level of genetic diversity in several populations. The present population genetic study will provide valuable information for the conservation and management of the Korean endemic fish species, I. paicifica.

• Clean Technology
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• v.13 no.1 s.36
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• pp.1-15
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• 2007

Biological treatment is a relatively recent air pollution control technology in which off-gases containing biodegradable odors and volatile organic compounds(VOCs) are vented through microbes. It is a promising alternative to conventional air pollution control methods. Bioreactors for air pollution control have found most of their success in the treatment of dilute and high flow waste air streams containing VOCs and odor compounds. They offer several advantages over traditional technologies such as incineration or adsorption. These include lower treatment costs, absence of formation of secondary pollutants, no spent chemicals, low energy demand and low temperature treatment. The three most widely used technologies are described, namely biofiltration, biotrickling filtration, bioscrubbing. The most widely used bioreactor for air pollution control is biofilter, but it has several limitations. In the past years major progress has been accomplished in the development of vapor phase bioreaction systems, for solving problems of biofilter. Biotrickling filters are more complex than biofilters, but are usually more effective, especially for the treatment of compounds which are difficult to degrade or compounds that generate acidic by-products. This, paper reviews fundamental and theoretical/practical aspect of air pollution control in biofilter, biotrickling filter and bioscrubber, focusing more extensively on biotrickling filtration. Special emphasis is given to the operating parameters and the factors influencing performance for air pollution control, and cost estimation in biotreatment technologies.

• Clean Technology
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• v.19 no.4
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• pp.355-369
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• 2013

Economic feasibility is one of the most important factors in energy production from regenerative biomass. From the aspect, biogas from anaerobic digestion of wastewater sludge is regarded as the most economical because of its cheap substrate and additional income from the disposal of waste sludge. Sludge hydrolysis has been regarded as the rate limiting step of anaerobic digestion and many sludge pre-treatment technologies have been developed to accelerate anaerobic sludge digestion for enhanced biogas production. Various sludge pre-treatment technologies including biological, thermo hydrolysis, ultrasonic, and mechanical methods have been applied to full-scale systems. Sludge pre-treatment increased the efficiency of anaerobic digestion by enhancing hydrolysis, reducing residual soilds, and increasing biogas production. This paper introduces the characteristics of various sludge pre-treatment technologies and the energy balance and economic feasibility of each technology were compared to prepare a guideline for the selection of feasible pre-treatment technology. It was estimated that thermophilic digestion and thermal hydrolysis were most economical technology followed by Cell rupture$^{TM}$, OpenCEL$^{TM}$, MicroSludge$^{TM}$, and ultrasound. The cost for waste sludge disposal shares the biggest portion in the economic analysis, therefore, water content of the waste sludge was the most important factor to be controlled.

• Journal of Life Science
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• v.25 no.6
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• pp.631-637
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• 2015

Streptavidin, a protein produced by Streptomyces avidinii, strongly binds up to four molecules of vitamin H, d-biotin exhibiting the dissociation constant of about 10⁻¹⁵ M. This strong binding affinity has been applied for detection and characterization of numerous biological molecules suggesting expression and purification of functional streptavidin should be very useful for the application of this streptavidin-biotin interaction. To express a soluble streptavidin in Escherichia coli, We synthesized streptavidin genes and cloned into pET-22b plasmid, which uses T7 RNA polymerase/T7 promoter expression systems containing pelB leader for secretion into periplasmic space and six polyhistidine tags at C-terminus for purification of expressed proteins. Although streptavidin is toxic to Escherichia coli due to strong biotin binding property, streptavidin was expressed very sufficiently in a range of 10-20 mg/ml. In SDS-PAGE, the size of purified protein was shown as 17 kDa in denatured condition (boiling) and 68 kDa in native condition (without boiling) suggesting tetramerization of monomeric subunit by non-covalent association. Further analysis by size-exclusion chromatography supported streptavidin’s tetrameric structure as well. In addition, soluble streptavidin detected biotinylated proteins in westernblot indicating its functional activity to biotin. Taken these results together, it concluded that our simple expression system was able to show high yield, homotetrameric formation and biotin binding activity analogous to natural streptavidin.

• Korean Journal of Agricultural and Forest Meteorology
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• v.18 no.1
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• pp.16-29
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• 2016

The total area of paddy field was estimated to be 55 % of the cultivated lands in South Korea, which is approximately 1 million hectares. Organisms inhabiting paddy fields if they are sensitive to environmental changes can be environmental indicator of paddy fields. Biological indicators such as phenology and distributional range are evaluated as intuitive and quantitative method to analyze the impact of climate change. This study aims to estimate flight time change of Hydrophilidae species' based on the RCP 8.5 climate change scenario. Unmanned monitoring systems were installed in Haenam, Buan, Dangjin and Cheorwon relative to the latitudinal gradient. In the three regions excepting Cheorwon, it was able to measure the abundance of flying Hydrochara affinis and Sternolophus rufipes. Degree-day for the flight time was determined based either on field measurement values and estimates of 2020s, 2050s and 2080s from KMA climate change scenario data. As a result, it is found that date of both species of initial flight becomes 15 days earlier, that of peak flight becomes 22 days earlier and that of final flight does 27 days earlier in 2080s compared to 2020s. The climate change impact on flight time is greater in coastal area, rural area and valley than inland area, urban area and plan. H. affinis and S. rufipes can be used as climate change indicator species.

• The Korean Journal of Physiology and Pharmacology
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• v.19 no.5
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• pp.389-399
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• 2015

Zinc has been considered as a vital constituent of proteins, including enzymes. Mobile reactive zinc ($Zn^{2+}$) is the key form of zinc involved in signal transductions, which are mainly driven by its binding to proteins or the release of zinc from proteins, possibly via a redox switch. There has been growing evidence of zinc's critical role in cell signaling, due to its flexible coordination geometry and rapid shifts in protein conformation to perform biological reactions. The importance and complexity of $Zn^{2+}$ activity has been presumed to parallel the degree of calcium's participation in cellular processes. Whole body and cellular $Zn^{2+}$ levels are largely regulated by metallothioneins (MTs), $Zn^{2+}$ importers (ZIPs), and $Zn^{2+}$ transporters (ZnTs). Numerous proteins involved in signaling pathways, mitochondrial metabolism, and ion channels that play a pivotal role in controlling cardiac contractility are common targets of $Zn^{2+}$. However, these regulatory actions of $Zn^{2+}$ are not limited to the function of the heart, but also extend to numerous other organ systems, such as the central nervous system, immune system, cardiovascular tissue, and secretory glands, such as the pancreas, prostate, and mammary glands. In this review, the regulation of cellular $Zn^{2+}$ levels, $Zn^{2+}$-mediated signal transduction, impacts of $Zn^{2+}$ on ion channels and mitochondrial metabolism, and finally, the implications of $Zn^{2+}$ in health and disease development were outlined to help widen the current understanding of the versatile and complex roles of $Zn^{2+}$.

• Journal of the Korean Applied Science and Technology
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• v.27 no.4
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• pp.559-567
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• 2010

In this study, the antioxidative effect, cellular protective effect and inhibitory effect on tyrosinase of Cosmos bipinnatus extracts were investigated. The ethyl acetate fraction of Cosmos bipinnatus flower extract ($11.48\;{\mu}g$/mL) showed more excellent free radical (1,1-diphenyl-2-picrylhydrazyl radical, DPPH) scavenging activity (FSC50) than those of leaf and stem extracts ($17.45\;{\mu}g$/mL). Reactive oxygen species (ROS) scavenging activity (OSC50) of Cosmos bipinnatus extracts on ROS generated in $Fe^{3+}$-EDTA/H2O2 system were investigated using the luminol-dependent chemiluminescence assay. The ethyl acetate fraction of Cosmos bipinnatus flower extract ($0.56\;{\mu}g$/mL) showed 3 times more excellent ROS scavenging activity than L-ascorbic acid ($1.50\;{\mu}g$/mL). The protective effects of the ethyl acetate fractions of extracts from different parts of Cosmos bipinnatus on the rose-bengal sensitized photohemolysis of human erythrocytes were investigated. The ethyl acetate fractions of leaf and stem extract and flower extracts suppressed photohemolysis in a concentration dependent manner ($10\sim50\;{\mu}g$/mL). The inhibitory effect of ethyl acetate fraction of Cosmos bipinnatus flower extract ($62.75\;{\mu}g$/mL) on tyrosinase was investigated to assess the whitening efficacy. The ethyl acetate fraction of Cosmos bipinnatus flower extract showed 3.5 times higher tyrosinase inhibitory effect than arbutin ($226.88\;{\mu}g$/mL) known as an effective whitening agent. These results indicate that fractions of Cosmos bipinnatus extracts can function as antioxidants in biological systems, particularly skin exposed to UV radiation by scavenging $^1O2$ and other ROS, and protect cellular membranes against ROS. Fractions of Cosmos bipinnatus extracts can be applicable to new functional cosmetics for antioxidant and whitening.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.4
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• pp.651-656
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• 2001

Ascorbic acid(AsA) is unevenly distributed throughout all body cells and fluids. Multiactivities of AsA in many biological systems and in various scientific fields were reported. In this study we aimed to clarify the inhibitory action of high concentration of AsA on the cell growth in 3T6 fibroblasts. The cells wee exposed to AsA at various concentration. It showed that 3T6 fibroblasts wee dead by the medium which contained AsA at the concentration higher than 0.5 mM. AsA caused hydrogen peroxide ($H_2O$$_2$) generation in a concentration dependent manner. These results suggested that the $H_2O$$_2$ was formed in the medium by AsA and acted as a cytotoxic gent. Moreover, it is supposed that hydroxyl radical (.OH) induced from $H_2O$$_2$also acetd as actively cytotoxic agent. This lethal effect of AsA causing the cell death was inhibited by the addition of catalase in the medium. Therefore, addition of AsA at the normal concentrations stimulate cell growth, but excess concentrations of AsA induce cell death.