• Journal of Power System Engineering
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• v.22 no.1
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• pp.48-55
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• 2018

It has recently been reported that methanol fuel has been used in the product carrier with established duel fuel engine, which has been greatly reducing emissions of $CO_2$, NOx and SOx from the engine. However, to use methanol alone as fuel oil in a general diesel engine, design modification of cylinder head is needed because the ignition aid device or the duel fuel injection system is needed. On the other hand, only if the mixer is installed on the fuel oil supply line, diesel oil - methanol blending oil can be used as fuel oil for the diesel engine, but there is a problem of the phase separation when two fuels are mixed. In this study, diesel oil and methanol were blended compulsorily in preventing the phase separation with installing agitators and a fuel oil boost pump on fuel line of a test engine. Also, cylinder pressure and fuel consumption quantity were measured according to engine load and methanol blending ratio, and indicated mean effective pressure, heat release rate and combustion temperature obtained from the single zone combustion model were analyzed to investigate the effects of latent heat of vaporization of methanol on combustion stability and characteristics. As a result, the combustion stability and characteristics of 10% methanol blending oil are closest to the those of diesel oil, and it could be used as fuel oil in existing diesel engines without deterioration of engine performance and combustion characteristics.

• Journal of Microbiology
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• v.40 no.2
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• pp.125-128
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• 2002

The aerobic respiratory chain of Vibrio alginolyticus possesses two different kinds of NADH oxidase systems, i.e., an $Na^{+}$-dependent NADH oxidase system and an $Na^{+}$-independent NADH oxidase system. When deamino-NADH, which is the only substrate for the $Na^{+}$-dependent NADH oxidase system, was used as a substrate, the maximum activities of $N^{+}$-dependent NADH: quinone oxidoreductase and $Na^{+}$-dependent NADH oxidase were obtained at about 0.06 M and 0.2 M NaCl, respectively. When NADH, which is a substrate for both $Na^{+}$-dependent and $Na^{+}$-independent NADH oxidase systems was used as a substrate, the NADH oxidase activity had a pH optimum at about 8.0. In cGntrastl when deamino-NADH was used as a substrate, the NADH oxidase activity had a pH optimum at about 9.0. On the other handle inside-out membrane vesicles prepared from the wild-type bacterium generated only a very small $\Delta$pH by the NADH oxidase system, whereas inside-out membrane vesicles prepared from Napl, which is a mutant defective in the $Na^{+}$ pump, generated $\Delta$pH to a considerable extent by the NADH oxidase system. On the basis of the results\ulcorner it was concluded that the respiratory chain-linked components of V. atginotyticus affect each other.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.12 no.3
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• pp.239-243
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• 2007

Presence of bottom water nitrite in the Ulleung Basin was remarkable because it is totally unexpected phenomenon at such an oxygen-rich environment. Yet no scientific explanation was set forward. Of several plausible explanations, following the Ockham's suggestion, a leaching of nitrite as an intermediate product of denitrification in the top sediment at the slope is most agreeable to given environmental settings. There seems no complementary process to make up the loss of N in the Ulleung Basin, which seems contribute to the characteristically low N:P ratio in the deep waters. If warming proceeds that weakens the thermohaline circulation, a current biological pump may stall and the phytoplankton assemblage might replaced drastically. If so this will pause an utmost challenge to the ecosystem of the East/Japan Sea. Still there remains a contradictory sedimentary signature that requests further explanation regarding the N (or organic C)-cycle such as extraordinarily high organic carbon content despite abundant oxidants in the overlying waters.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.2A
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• pp.123-130
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• 2012

A cooling system is indispensable for the fossil and nuclear power plants which produce electricity by rotating the turbines with hot steam. A cycle of the typical cooling system includes pumping of seawater at the intake pump house, exchange of heat at the condenser, and discharge of hot water to the sea. The cooling type of the nuclear power plants in Korea recently evolves from the conventional surface intake/discharge systems to the submerged intake/discharge systems that minimize effectively an intake temperature rise of the existing plants and that are beneficial to the marine environment by reducing the high temperature region with an intensive dilution due to a high velocity jet and density differential at the mixing zone. It is highly anticipated that the future nuclear power plants in Korea will accommodate the submerged cooling system in credit of supplying the lower temperature water in the summer season. This study investigates the approach flow patterns at the velocity caps and discharge flow patterns from diffusers using the 3-D computational fluid dynamics code of $FLOW-3D^{(R)}$. The approach flow test has been conducted at the velocity caps with and without a cap. The discharge flow from the diffuser was simulated for the single-port diffuser and multi-ports diffuser. The flow characteristics to the velocity cap with a cap demonstrate that fish entrainment can significantly be minimized on account of the low vertical flow component around the cap. The flow pattern around the diffuser is well agreed with the schematic diagram by Jirka and Harleman.

• Journal of Life Science
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• v.26 no.12
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• pp.1392-1399
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• 2016

Jaspine B is an anhydrophytosphingosine that is isolated from a marine sponge. Because of its structural similarity to sphingosine, it shows anti-cancer effects in human carcinomas. Therefore, this study aims to investigate its anti-proliferative effect on various cancer cells and to correlate its association with the intracellular accumulation of Jaspine B in relevant cancer cells. The anti-proliferative effect of Jaspine B in various cancer cells was determined by a cell viability test, and the intracellular concentration of Jaspine B in relevant cancer cells was determined using mass spectrometry coupled with liquid chromatography. The correlation coefficient and p value between the cytotoxicity and the cell accumulation of Jaspine B were determined using SPSS 16.1. The cytotoxicity of Jaspine B varied depending on the type of cancer cell when compared the $EC_{50}$ values of Jaspine B. Breast and melanoma cancer cells were susceptible to Jaspine B, whereas renal carcinoma cells were resistant. The intracellular concentrations of Jaspine B had a reciprocal correlation with the $EC_{50}$ values in the same cells (r = 0.838). The results suggested that the anti-proliferative effect of Jaspine B was associated with the cellular accumulation of this compound. However, Jaspine B was not a substrate for P-glycoprotein and breast cancer resistance protein, as major efflux pumps caused multidrug resistance. The maintenance of a high intracellular concentration is crucial for the cytotoxic effect of Jaspine B; however, efflux pumps may not be a controlling factor for Jaspine B-related resistance in cancer cells.

• Journal of fish pathology
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• v.18 no.1
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• pp.91-97
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• 2005

Bio-secure culture of olive flounder Paralichthys olivaceus in the IBK (Intensive Bioproduction Korean) recirculating system with dry pellet was tested for 6 months. The IBK system consists of 12 rearing tanks, 6 sedimentation tanks. 4-sectioned submerged biofilter chamber and channels. The size of each rearing tank was 3m in diameter and 1m in depth. The size of each biofilter chamber was $3.1\times3.3\times2.0$ m (D) and was filled with corrugated plastic plates as a biofilter medium. Total surface area of the biofilter was 3,789.7 $m^2$ Water was circulated by one of two vertical axial pump and circulating rate was about 34 times per day. A UV light sterilizer was used to treat inlet sea water with the flow rate of 4 ton/hr. All fish were treated with 150 ppm formalin 3 times with 5 day interval before stocking. It took 60 days for 'conditioning' the biofilter with the stocking density of 4.5 kg of fish $m^2$. The concentrations of ammonium-nitrogen, nitrite-nitrogen and nitrate-nitrogen in the system remained at the range of 0.096-0.315 mg/L, 0.015-0.504 mg/L, and 2.530-39.517 mg/L, respectively. Water temperature fluctuated from 17.5 to 25.1$^{\circ}C$ and salinity was from 30.1 to 33.5 ppt during rearing period. The fish grew from the average weight of 615.2 g to 1,201.1 g for 180 days. Initial and final fish densities were 8.4 and 15.9$kg/m^2$, Survival rate was 97.1 %. Neither parasites nor noticeable diseases was observed during the raring period even Vibrio spp. were detected from some fish in the system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.3
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• pp.136-143
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• 2016

To provide a type approval test for Ballast Water Treatment System (BWTS) of United States Coast Guard (USCG) Phase-II, this study examined the concentrating efficiency of nets for ${\geq}10{\mu}m$ and ${\leq}50{\mu}m$ sized phytoplanktonic organisms using different mesh sized nets ($5{\mu}m$ or $7{\mu}m$), different injection methods (hand breaker as semi-continuous assessment or pump as continuous assessment), and different filterability for the water volume. As a result of the t-test, the net concentrated efficiency between $5{\mu}m$ and $7{\mu}m$ mesh size was not significant (p > 0.05). The difference in the net concentrated efficiency for filtered natural water volume was not significant (p > 0.05). On the other hand, the Chl.a concentration in the continuous water injection method was significantly (p < 0.05) higher than that of semi-continuous water injection (t-test: t: -4.058). In the natural phytoplankton community, a total of 36 species were identified, including Bacillariophyta (17 species), Dinophyta (15 species), Euglenophyta (1 species), Dictyochophyta (2 species), and unidentified taxa (1 species). Among them, diatom Pseudo-nitzchia spp. was remarkably dominant. In particular, the net concentrated efficiency in all assessments was underestimated to be approximately 20-25%, which was caused by the small size Pseudo-nitzchia spp.. A width size of these genus might have passed through the $5{\mu}m$ or $7{\mu}m$ mesh size of the net. Therefore, net concentrated efficiency is dependent on the size of the observed species in natural water. This issue should be considered when determining the net volume for the type approval test of BWTS.

• Journal of Life Science
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• v.27 no.11
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• pp.1369-1375
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• 2017

The purpose of this study was to investigate the cellular characterization of phospholipase C-${\delta}1$ in olive flounders (Paralichthys olivaceus). In general, phospholipase C signaling pathways are distributed in nuclei at plasma membranes and in cytoplasms, although the pathways' nuclear localization mechanisms are unclear. P. olivaceus duplicates type-A PoPLC-${\delta}1$ (PoPLC-${\delta}1A$), which has a high similarity to the human isoform PLC-${\delta}$; type-B PoPLC-${\delta}1$ (PoPLC-${\delta}1B$ [Sf]), which has a low similarity to the human isoform PLC-${\delta}$ and the alternative splice variant PoPLC-${\delta}1B$ (Lf), which has a nuclear localization signal (NLS) and a nuclear export signal (NES) for nuclear imports and exports, respectively. This study confirmed the effects of the cellular localization and translocation of GFP-tagged PoPLC-${\delta}1A$, PoPLC-${\delta}1B$ (Sf) and PoPLC-${\delta}1B$ (Lf). It administered treatments of $Ca^{2+}$ ionophore ionomycin and endoplasmic reticulum (ER)-$Ca^{2+}$ pump inhibitor thapsigargin to hirame natural-embryo (HINAE) cells. A laser-scanning confocal microscope was used. GFP-tagged PoPLC-${\delta}1A$ was distributed to the cellular organelles, rather than to the cytoplasms and cytomembranes, when PoPLC-${\delta}1B$ (Lf) and PoPLC-${\delta}1B$ (Sf) were localized at the plasma membranes. The treatments of ionomycin and thapsigargin showed the accumulation of PoPLC-${\delta}1A$ in the nuclei when PoPLC-${\delta}1B$ (Lf) nucleocytoplasmic shuttling and PoPLC-${\delta}1B$ (Sf) nucleocytoplasmic shuttling were not observed. The results were the first evidence that PoPLC-${\delta}1A$, which contains functional, intact NES sequences, has a main role in nucleocytoplasmic shuttling and translocation in fish.