• Archives of Pharmacal Research
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• v.23 no.1
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• pp.1-16
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• 2000

Many natural products elicit diverse pharmacological effects. Using two classes of potential chemopreventive compounds, the phenolic compounds and the isothiocyanates, we review the potential utility of two signaling events, the mitogen-activated protein kinases (MAPKs) and the ICE/Ced-3 proteases (caspases) stimulated by these agents in mammalian cell lines. Studies with phenolic antioxidants (BHA, tBHQ), and natural products (flavonoids; EGCG, ECG, and isothiocyanates; PEITC, sulforaphane), provided important insights into the signaling pathways induced by these compounds. At low concentrations, these chemicals may activate the MAPK (ERK2, JNK1, p38) leading to gene expression of survival genes (c-Fos, c-Jun) and defensive genes (Phase II detoxifying enzymes; GST, QR) resulting in survival and protective mechanisms (homeostasis response). Increasing the concentrations of these compounds will additionally activate the caspase pathway, leading to apoptosis (potential cytotoxicity). Further increment to suprapharmacological concentrations will lead to nonspecific necrotic cell death. The wider and narrow concentration ranges between the activation of MAPK/gene induction and caspases/cell death exhibited by phenolic compounds and isothiocyanates, respectively, in mammalian cells, may reflect their respective therapeutic windows in vivo. Consequently, the studies of signaling pathways elicited by natural products will advance our understanding of their efficacy and safety, of which many man become important therapeuitc drugs of the future.

• Tunnel and Underground Space
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• v.10 no.4
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• pp.553-558
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• 2000

Since 1977, KAERI has conducted the fundamental R&D on the permanent disposal of potential HLW repository in Korea. The first ten year project is divided into three short-term phase studies. The first phase study which shall be finished in March of 2000, has the prime target to develop the disposal concept of HLW. Throughout this study the preliminary and generic disposal repository system has been introduced. The potential repository is proposed to be emplaced into crystalline rocks which is the most common rock types in Korea. The proposed depth of the repository is between 300 to 700 meter. The numerical code, MASCOT-K was developed to asserts the long term safety of the proposed repository concept. Based on this conceptual design preliminary safely assessment was performed. Results show that for the given disposal system the potential radioactive release it well below the regulatory limit.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.20 no.3
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• pp.268-276
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• 2008

Potential tsunamis generated in Okinawa Trough were simulated for the investigation of the propagation characteristics in the southwestern sea of Korean Peninsula. Shallow waters in the continental shelf of East China Sea and deep waters in Okinawa Trough play an important role in the propagation characteristics of the tsunamis generated in this region. The propagation characteristics can be classified into two phases according to the stage of propagation. In the first phase, the tsunamis propagate both northeast and southwest along the deep water of the trough. In the second phase, the tsunamis enter the continental shelf of the East China Sea at right angles to topographic contour lines. Simulated results show that the tsunamis generated in the Okinawa Trough give a weak influence to the southern and western coasts of Korea due to the special topography of the southwestern sea of Korean Peninsula.

• Proceedings of KOSOMES biannual meeting
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• 2004.11a
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• pp.117-122
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• 2004

In order to investigate the initial stage of deep water formation between Vladivostok and the subpolar front in the East Sea, the factors, temperature, salinity, dissolved oxygen, measured by multi-ship surveys in 1969 have been used Deep water formation in the East Sea occurs in essentially two different forms: near continent and open ocean formation the position of eddy derived from potential vorticity matches well with that of deep water formation. The vertical and horizontal distributions of potential vorticity, geostrophic current, temperature, salinity and dissolved oxygen give clues for the preconditioning phase of open ocean formation like a doming of isotherm, associated with a cyclonic circulation

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.11
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• pp.6481-6486
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• 2013

Background: Our previous study demonstrated cytotoxicity of a crude extract from Patrinia heterophylla Bunge (PHEB). In the present study, we aimed to investigate the effects of isovaltrate acetoxyhydrin (IA) isolated from PHEB on the gastric cancer cell SGC-7901, in order to explore a potential treatment for gastric cancer. Methods: MTT assays were employed to determine the effects of IA on cell vitality and proliferation, with monitoring of cell morphology changes and examination of apoptosis with Annexin V-PI staining. Flow cytometry was used to assess cell cycle progression and mitochondrial membrane potential. The activity of caspase 3, 9 was evaluated by spectrophotometry, and the protein levels of Bax, Bcl2 and Cyclin B1 were analyzed with Western blotting of total proteins extracted from cultured cells. Results: The results demonstrated direct toxicity of IA towards SGC-7901 cells. Evidence of apoptosis included blebbing and chromatin condensation. Annexin V-PI assays revealed early apoptosis, involving rapid depolarization of mitochondrial membranes and activity of caspase 3, 9 signaling pathways. Western blotting showed that Bcl2 and Bax proteins was down- and up-regulated, respectively, and cyclin B1 was up-regulated. Cell cycle analysis further indicated that IA could induce G2/M phase arrest in SGC-7901 cells. Conclusions: In conclusion, we believe that IA induces apoptosis of SGC-7901 cells, therefore providing a potential therapeutic agent for treatment of gastric cancer.

• Journal of Korean Society for Atmospheric Environment
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• v.27 no.6
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• pp.703-710
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• 2011

Odor emission from domestic sewer systems has become a serious environmental problem. An investigation on a sewer manhole revealed that anaerobic decay of sediment organic matters (SOMs) and related declines of oxidation reduction potential (ORP) in the sediment layer were the main reason of the production of volatile sulfur compounds. In addition, as the anaerobic decaying period continued, the odor intensity rapidly increased with increasing concentrations of $H_2S$ and dimethyl sulfide. As a feasible method to control SOMs and to minimize odor emission potentials, an electrolytic oxidation process has been employed to the sediment sludge phase. In this study, voltages applied to the electrolytic oxidation process were varied as a main system parameter, and its effects on odor removal efficiencies and reaction characteristics were investigated. At the applied voltages greater than 20 V, the system efficiently oxidized the organic matter, and the ORP in the sludge phase increased rapidly. As a consequence, the removal efficiency of hydrogen sulfide was found to be >99% within 60 minutes of the electrolytic oxidation. Overall, the electrolytic oxidation process can be an alternative to control odor emission from sewer systems, and a threshold input energy needs to be determined to achieve effective operation of the process.

• Journal of the Korean Society of Marine Environment & Safety
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• v.11 no.1 s.22
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• pp.77-82
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• 2005

In order to investigate the initial stage of deep water formation between Vladivostok and the subpolar front in the East Sea, the factors, temperature, salinity, dissolved oxygen, measured by multi-ship surveys in ]969 have been used. Deep water formation in the .cast Sea occurs in essentially two different forms: near continent and open ocean formation. The position of eddy derived from potential vorticity matches well with that of deep water formation. The vertical and horizontal distributions of potential vorticity, geostrophic current, temperature, salinity and dissolved oxygen give clues for the preconditioning phase qf open ocean formation like a doming of isotherm, associated with a cyclonic circulation.

• Journal of Ship and Ocean Technology
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• v.10 no.4
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• pp.1-11
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• 2006

The finite volume based multi-block RANS code, WAVIS developed at MOERI is applied to the numerical self-propulsion test. WAVIS uses the cell-centered finite volume method for discretization of the governing equations. The realizable $k-{\epsilon}$ turbulence model with a wall function is employed for the turbulence closure. The free surface is captured with the two-phase level set method and body forces are used to model the effects of a propeller without resolving the detail blade flow. The propeller forces are obtained using an unsteady lifting surface method based on potential flow theory. The numerical procedure followed the self-propulsion model experiment based on the 1978 ITTC performance prediction method. The self-propulsion point is obtained iteratively through balancing the propeller thrust, the ship hull resistance and towing force that is correction for Reynolds number difference between the model and full scale. The unsteady lifting surface code is also iterated until the propeller induced velocity is converged in order to obtain the propeller force. The self-propulsion characteristics such as thrust deduction, wake fraction, propeller efficiency, and hull efficiency are compared with the experimental data of the practical container ship. The present paper shows that hybrid RANS and potential flow based numerical method is promising to predict the self-propulsion parameters of practical ships as a useful tool for the hull form and propeller design.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.11
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• pp.1559-1569
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• 2002

In order to investigate the characteristics of electromagnetic flowmeter in two -phase flow, an AC electromagnetic flowmeter was designed and manufactured. In various flow conditions, the signals and noises from the flowmeter were obtained and analyzed by comparison with the observed flow patterns with a high speed CCD camera. The experiment with the void simulators in which rod shaped non-conducting material was used was carried out to investigate the effect of the bubble position and the void fraction on the flowmeter. Based on the results from the void simulator, two -phase flow experiments encompassed from bubbly to slug flow regime were conducted. The simple relation $\Delta$ $U_{TP}$ = $\Delta$ $U_{SP}$ (l-$\alpha$) was verified with measurements of the potential difference and the void fraction. Due to the lack of homogeneity in a rent two -phase flow, the discrepancy between the relation and the present measurement was slightly increased with void fraction and also liquid volumetric flux jf. Whereas there is no difference in the shape of the raw signal between single-phase flow and bubbly flow, the signal amplitude for bubbly flow is higher than that for single -phase flow at the same water flow rate, since the passage area of the water flow is reduced. In the case of slug flow, the phase and the amplitude of the flowmeter output show dramatically the flow characteristics around each slug bubble and the position of a slug bubble itself. Therefore, the electromagnetic flowmeter shows a good possibility of being useful for identifying the flow regimes.ul for identifying the flow regimes.

• Journal of KIISE:Computer Systems and Theory
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• v.29 no.11
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• pp.611-621
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• 2002

For real-time systems, multiprocessor support is indispensable to handle the large number of requests. Existing real-time on-line scheduling algorithms such as Earliest Deadline First Algorithm (EDF) and Least Laxity Algorithm (LLA) may not be suitable for scheduling real-time tasks in multiprocessor systems. Although EDF has low context switching overhead, it suffers from "multiple processor anomalies." LLA has been shown as suboptimal, but has the potential for higher context switching overhead. Earliest Deadline Zero Laxity (EDZL) solved somewhat the problems of those algorithms, however is suboptimal for only two processors. Another algorithm EDA2 shows very good performance in overload phase, however, is not suboptimal for muitiprocessors. We propose two on-line scheduling algorithms, Earliest Deadline/Least Laxity (ED/LL) and ED2/LL. ED/LL is suboptimal for multiprocessors, and has low context switching overhead and low deadline miss rate in normal load phase. However, ED/LL is ineffective when the system is overloaded. To solve this problem, ED2/LL uses ED/LL or EDZL in normal load phase and uses EDA2 in overload phase. Experimental results show that ED2/LL achieves good performance in overload phase as wet] as in normal load phase.oad phase.