• Korean Journal of Food Science and Technology
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• v.38 no.2
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• pp.159-164
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• 2006

Volatile components of Phellinus linteus produced from different areas were collected by simultaneous steam distillation-solvent extraction method (SDE). Concentrated extracts analyzed and identified by GC and GC-MS showed musty and earthy characteristics. 2-Methylphenol, methoxy benzene, coumaran, azulene, ${\alpha}-cedrene,\;{\alpha}-longipinene,\;{\beta}-selinene,\;{\alpha}-selinene$, camphor, ${\gamma}-ionone,\;{\beta}-ionone$, phytol, and borneol not reported in other edible mushrooms, were identified and/or tentatively identified in P. linteus for the first time. Main volatile components of P. linteus (Busan-Jinsung: BJ) were phytol from chlorophyll and methoxy benzenes having musty odor. Volatile components of P. linteus (Jinju-Kumwhang: JK) resembled those of BJ, but with high concentration of phenylacetaldehyde contributing to flower-odor. P. linteus (Cheju-Gullim: CG) contained low concentration of methoxy benzenes, but high concentration of phenylacetaldehyde. Low concentrations of ${\gamma}-ionone\;and\;{\beta}-ionone$ were identified in three kinds of P. linteus. They appeared to have been produced from degradation of carotenoid, which suggests P. linteus contains a carotenoid pigment.

• Molecules and Cells
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• v.37 no.11
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• pp.785-794
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• 2014

Mitophagy, a cellular process that selectively targets dysfunctional mitochondria for degradation, is currently a hot topic in research into the pathogenesis and treatment of many human diseases. Considering that hypoxia causes mitochondrial dysfunction, which results in cell death, we speculated that selective activation of mitophagy might promote cell survival under hypoxic conditions. In the present study, we introduced the Regulator of calcineurin 1-1L (Rcan1-1L) to initiate the mitophagy pathway and aimed to evaluate the effect of Rcan1-1L-induced mitophagy on cell survival under hypoxic conditions. Recombinant adenovirus vectors carrying Rcan1-1L were transfected into human umbilical vein endothelial cells and human adult cardiac myocytes. Using the 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide MTT assay and Trypan blue exclusion assay, Rcan1-1L overexpression was found to markedly reverse cell growth inhibition induced by hypoxia. Additionally, Rcan1-1L overexpression inhibited cell apoptosis under hypoxic conditions, as detected by annexin V-fluorescein isothiocyanate (FITC)/propidium iodide (PI) apoptosis assay. Meanwhile, the mitochondria-mediated cell apoptotic pathway was inhibited by Rcan1-1L. In contrast, knockdown of Rcan1-1L accelerated hypoxia-induced cell apoptosis. Moreover, Rcan1-1L overexpression significantly reduced mitochondrial mass, decreased depolarized mitochondria, and downregulated ATP and reactive oxygen species production. We further delineated that the loss of mitochondrial mass was due to the activation of mitophagy induced by Rcan1-1L. Rcan1-1L overexpression activated autophagy flux and promoted translocation of the specific mitophagy receptor Parkin into mitochondria from the cytosol, whereas inhibition of autophagy flux resulted in the accumulation of Parkin-loaded mitochondria. Finally, we demonstrated that mitochondrial 1permeability transition pore opening was significantly increased by Rcan1-1L overexpression, which suggested that Rcan1-1L might evoke mitophagy through regulating mitochondrial permeability transition pores. Taken together, we provide evidence that Rcan1-1L overexpression induces mitophagy, which in turn contributes to cell survival under hypoxic conditions, revealing for the first time that Rcan1-1L-induced mitophagy may be used for cardioprotection.

• KSBB Journal
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• v.21 no.2
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• pp.151-156
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• 2006

Vitamin-C is one of the typical bioactive substances widely used in the cosmetic and pharmaceutical applications. It is well known that the bioavailability of vitamin-C decreases with time because it is spontaneously oxidized in the presence of oxygen. In this study, vitamin-C inclusion complexes were prepared by formulating vitamin-C with 2-hydroxypropyl-${\beta}$-cyclodextrin (HP-${\beta}$-CD) to protect vitamin-C from being oxidized. Vitamin-C inclusion complexes were prepared by a solvent evaporation method using a rotary evaporator and various solvents of different dielectric constant such as ethanol, methanol and distilled deionized water to investigate the effect of solvent polarity on the stability of vitamin-C. To estimate the stability of inclusion complexes, samples were stored in a 50 mM phosphate buffer solution of pH 7.0 for 24 hours at $25{\pm}0.1^{\circ}C$ and the degradation rate of vitamin-C was calculated using a high performance liquid chromatography. The stability of vitamin-C was observed to improve with the increase of solvent polarity.

• Journal of Korean Society for Atmospheric Environment
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• v.24 no.1
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• pp.91-99
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• 2008

A multilayer tower-type photoreactor, in which $TiO_2$-coated glass-tubes were installed, was used to measure the vapor-phase BTEX removal efficiencies by ozone oxidation ($O_3$/UV), photocatalytic oxidation ($TiO_2$/UV) and the combination of ozone and photocatalytic oxidation ($O_3/TiO_2$/UV) process, respectively. The experiments were conducted under various relative humidities, temperatures, ozone concentrations, gas flow rates and BTEX concentrations. As a result, the BTEX removal efficiency and the oxidation rate by $O_3/TiO_2$/UV system were highest, compared to $O_3$/UV and $TiO_2$/UV system. The $O_3/TiO_2$/UV system accelerated the low oxidation rate of low-concentration organic compounds and removed organic compounds to a large extent in a fixed volume of reactor in a short time. Therefore, $O_3/TiO_2$/UV system as a superimposed oxidation technology was developed to efficiently and economically treat refractory VOCs. Also, this study demonstrated feasibility of a technology to scale up a photoreactor from lab-scale to pilot-scale, which uses (i) a separated light-source chamber and a light distribution system, (ii) catalyst fixing to glass-tube media, and (iii) unit connection in series and/or parallel. The experimental results from $O_3/TiO_2$/UV system showed that (i) the highest BTEX removal efficiencies were obtained under relative humidity ranging from 50 to 55% and temperature ranging from 40 to $50^{\circ}C$, and (ii) the removal efficiencies linearly increased with ozone dosage and decreased with gas flow rate. When applying Langmuir-Hinshelwood model to $TiO_2$/UV and $O_3/TiO_2$/UV system, reaction rate constant for $O_3/TiO_2$/UV system was larger than that for $TiO_2$/UV system, however, it was found that adsorption constant for $O_3/TiO_2$/UV system was smaller than that for $TiO_2$/UV system due to competitive adsorption between organics and ozone.

• Environmental Mutagens and Carcinogens
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• v.26 no.4
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• pp.125-132
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• 2006

Previous studies showed that epigallocatechin gallate(EGCG) have substantial effects of suppressing the N-methyl-N'-nitro-N-nitrosoguanidine(MNNG)-initiated cell transformation process on the bases of foci formation frequency and loss of anchorage dependency. In this study we tried to clarify the molecular mechanism of suppressing the cell transformation process. Mouse cell line balb/c 3T3 A31-1-1 was exposed 2 days to MNNG followed by 15 days 12-O-tetradecanoylphorbol-13-acetate(TPA) treatment for our transformation process. EGCG was added after the time point of 24 hours exposure to TPA and incubated for 19 days. 2029 genes were selected in our transformation process that showed fold change value of 1.5 or more in the microarray gene expression analysis covering the mouse full genome. These genes were found to be involved mainly in the cell cycle pathway, focal adhesion, adherens junction, TGE-$\beta$ signaling, apoptosis, lysine degradation, insulin signaling, ECM-receptor interaction. Among the genes, we focused on the 631 genes(FC>0.5) reciprocally affected by EGCG treatment. Our study suggest that EGCG down-regulate the gene expressions of up stream signaling factors such as nemo like kinase with MAPK activity and PI3-Kinase, Ras GTPase and down stream factors such as cyclin D1, D2, H, T2, cdk6.

• Journal of KIISE:Databases
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• v.28 no.3
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• pp.468-483
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• 2001

In order to enhance the performance, cursor stability, which is a variant of isolation lvel 2 in relational DBMSs, has been widely used in place of isolation level 3, which uses strict two phase locking. However, cursor stability is much less usable in object-relational DBMSs (ORDBMSs) because navigational applications in ORDBMSs can suffer from critical inconsistency problems such as dangling pointers, lost updates, and reading inconsistent complex objects. In this paper, we propose a new isolation level, navigation stability, that prevents the inconsistency problems of cursor stability for navigational applications, while avoiding significant degradation of the concurrency of level 3. First, we analyze the inconsistency problems of cursor stability for navigational applications. Second, we define navigation stability as an extension of cursor stability and show that it solves those inconsistency problems of cursor stability in ORDBMSs. For workloads consisting of transactions of long duration, compared with level 3, the throughput of navigation stability is enhanced by up to 200%; the average response time reduced by as much as 55%; and the abort ratio reduced by as much as 77%. From these results, we conclude that navigation stability is a useful isolation level in ORDBMSs that can be used in place of isolation level 3 to improve the performance and concurrency without significantly sacrificing consistency.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.3
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• pp.497-505
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• 2015

Existing Wi-Fi networks require users to follow network settings of the AP (Access Point), resulting in inconveniences for users, and the password of the AP is shared by all users connected to the AP, causing security information leaks as time goes by. We propose, in this work, a personalized secure Wi-Fi network, in which each user is assigned her own virtual Wi-Fi network. One virtual Wi-Fi per user makes the user-centric network configuration possible. A user sets a pair of her own SSID and password on her device a priori, and the AP publishes its public key in a suitable way. The AP also maintains an open Wi-Fi channel, to which users can connect anytime. On user's request, the user device sends a connection request message containing a pair of SSID and password encrypted with the AP's public key. Receiving the connection request message, the AP instantiates a new virtual AP secured with the pair of SSID and password, which is dedicated to that single user device. This virtual network is securer because the password is not shared among users. It is more convenient because the network adapts itself to the user device. Experiments show that these advantages are obtained with negligible degradation in the throughput performance.

• Journal of Surface Science and Engineering
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• v.52 no.6
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• pp.283-288
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• 2019

MCrAlY overaly coatings are used as oxidation barrier coatings to prevent degradation of the underlying substrate in high temperature and oxidizing environment of the hot section of gas turbines. Therefore, oxidation resistance in high temperature is important property of MCrAlY coatings. Also, coefficients of thermal expansion (CTE) of MCrAlY have middle value of that of Ni-based superalloys and oxides, which have the effect of preventing the delamination of the surface oxides. Cyclic oxidation test is one of the most useful methods for evaluating the high temperature durability of coatings used in gas turbines. In this study, NiCoCrAlY overlay coatings were formed on Inconel 792(IN 792) substrates by vacuum plasma spraying process. Vacuum plasma sprayed NiCoCrAlY coatings and IN 792 susbstrates were exposed to 1000℃ one-hour cyclic oxidation environment. NiCoCrAlY coatings showed lower weight gain in short-term oxidation. In long-term oxidation, IN 792 substrates showed higher weight loss due to delamination of surface oxide but NiCoCrAlY coatings showed lower weight loss. X-ray diffraction (XRD) analysis showed α-Al2O3 and NiCr₂O₄ was formed during the cyclic oxidation test. Through cross-section observation using scanning electron microscopy (SEM) and electron back scatter diffraction (EBSD) analysis, thermally grown oxide (TGO) layer composed of α-Al₂O₃ and NiCr₂O₄ was formed and the thickness of TGO increased during 1000℃ cyclic oxidation test. β phase in upper side of NiCoCrAlY coating was depleted due to oxidation of Al and outer beta depletion zone thickness also increased as the cyclic oxidation time increased.

• Korean Journal of Environmental Agriculture
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• v.16 no.4
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• pp.320-326
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• 1997

In order to elucidate the degradation characteristics of the herbicide imazapyr in soil, mineralization to $^{14}CO_2$and adsorption were investigated using eight types of soils with the different physico-chemical properties. The results obtained were as follows: 1. During the incubation period of 12 weeks after the treatment of imazapyr, the amounts of $^{14}CO_2$ evolved from 8 types of soils with different properties ranged from 1.5 to 4.9% of the originally applied $^{14}C$ activities. Soil C, G, and H with low pH and high organic matter showed low $^{14}CO_2$evolution, whereas soil B and D with high pH and low organic matter did high $^{14}CO_2$ evolution. 2. Time for reaching the equilibrium concentrations in the adsorption experiment of imazapyr in soils was about 3 hours at $25^{\circ}c$ in soil C, D, G, and H. Imazapyr was adsorbed in the range of 0.25${\sim}$28.32% in soils with different physico-chemical properties. Among the soil parameters, organic matter content was the most influential in imazapyr adsorption on soil. The Freundlich adsorption coefficient $(K_f)$ increased 5.5 to 25.6 times as organic matter content increased 2.0 to 21.3 times. Hence it seems that the extent to which soil organic matter contributes to imazapyr adsorption is greater than that of clay mineral. $K_f$ values for the soils tested were 0.44, 0.08, 0.65, and 2.05 in soil C, D, G, and H, respectively. In all the soils tested, $K_f$ values had a strong resemblance to K_$K_d$.

• Applied Biological Chemistry
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• v.39 no.5
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• pp.403-408
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• 1996

Total bacterial community DNA, which was extracted from microcosm soil and field soil after 2,4-D amendments, was analyzed on Southern blots, using the tfdA gene probe derived from plasmid pJP4 and the Spa probe from Sphingomonas paucimobilis. Southern blot analyses with total bacterial DNA extracted from soils Inoculated with Pseudomonas cepacia/pJP4 revealed that DNA probe method could detect the 2,4-D degrading bacteria down to $10^5\;cells/g$ dry soil. In the microcosm experiment, there was a good correlation between 2,4-D degradation and banding patterns in hybridization analyses performed after each 2,4-D treatment using the two probes. When bacterial DNA extracted from microcosm soil was hybridized with the Spa probe, a change in the position of hybrid bands was observed over time in a Southern blot, suggesting that population change or possibly genetic rearrangement in 2,4-D degrading microbial populations occurred in this soil. With the Spa probe, one hybrid DNA band was persistently observed throughout the five 2,4-D additions. When bacterial DNA isolated from the field soil was probed with the tfdA and Spa, strong hybridization signal was observed in the 100 ppm-treated subplot, weak signal In the 10 ppm-treated subplot, and no significant signal in the 1 ppm-treated and control subplots. The data show that DNA probe analyses were capable of detecting and discriminating the indigenous 2,4-D degrading microbial populations in soil amended with 2,4-D under laboratory and field conditions.