• Journal of the Korean Society of Marine Environment & Safety
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• v.16 no.4
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• pp.339-344
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• 2010

Oxygen depleted water mass can damage aquatic animals not only in direct way but also in indirect way by generating toxic substances including occurrence of hydrogen sulfide and ammonia which are also highly detrimental to animal life in the water mass. An oxygen dissolution device was developed, which makes turnover of the oxygen rich (over 20 mg/L) surface water down to the bottom where hypoxia is evident and tested the device in terms of oxygen recovery in the oxygen depleted bottom water. the device with turnover rates of $3.6\;m^2$/min at the liquid oxygen injection rate of 48~26.3 L/min could recover dissolved oxygen level to 7~25 mg/L at depth 7 m to lead to the dissolution level of over 90% by the supply of liquid oxygen. The running advantage of the device is that it does not require any auxiliary tank and higher energy for operation. Therefore, it can be highly useful device to relieve damages to the farmed animals in the oxygen depleted waters.

• Reproductive and Developmental Biology
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• v.34 no.1
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• pp.47-53
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• 2010

Glycoprotein hormones have a common $\alpha$-subunit that is involved in the signaling pathway together with G protein, adenylcyclase and cAMP induction; however, it is an unclear how this common structure is related to hormonal action. To determine the biological functions of the COOH-terminal amino acids in the $\alpha$-subunit of these glycoprotein hormones, a tethered-molecule was constructed by fusing the $NH_2$-terminus of the $\alpha$-subunit to the COOH-terminus of the $\beta$-subunit of equine chorionic gonadotropin (eCG). The following deletion mutants were created by PCR; Ile was inserted at position 96 to form ${\Delta}96$, Lys was substituted at position 95 to form ${\Delta}95$, His was inserted at position 93 to form ${\Delta}93$ and Tyr was substituted at position 87 to form ${\Delta}87$. Each mutant was transfected into CHO-K1 cells. Tethered-wt eCG, and ${\Delta}96$, ${\Delta}95$, and ${\Delta}93$ mutants were efficiently secreted into the medium but the ${\Delta}87$ mutant was not secreted. Interestingly, the RT-PCR, real-time PCR, and northern blot analyses confirmed that the RNA was transcribed in the ${\Delta}87$ mutant. However, the ${\Delta}87$ mutant protein was not detected in the medium or the intracellular fraction of the cell lysates. The LH- and FSH-like activities of the recombinant proteins were assayed in terms of cAMP production using rat LH/CG and rat FSH receptors. The metabolic clearance rate (MCR) was determined by injecting rec-eCG (2 IU) into the tail vein. The ${\Delta}95$ and ${\Delta}93$ mutants were completely inactive in both the LH- and FSH-like activity assays. The ${\Delta}96$ mutant showed slight activity in the LH-like activity assay. In comparison to the wild type, the activity of the ${\Delta}96$ mutant in the FSH-like activity assay was the highest among all the mutants. The MCR assay in which rec-eCG was injected showed a peak at 10 min in all the treatment groups, which disappeared 4 h after injection. These results imply a direct interaction between the receptor and the COOH-terminal region of the a-subunit. The data also reveal a significant difference in the mechanism by which the eCG hormone interacts with the rLH and rFSH receptors. The COOH-terminal region of the $\alpha$-subunit is very important for the secretion and functioning of this hormone.

• Analytical Science and Technology
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• v.7 no.3
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• pp.361-369
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• 1994

Voltammetric behavior of some light lanthanide ions($La^{3+}$, $Pr^{3+}$, $Nd^{3+}$, $Sm^{3+}$ and $Eu^{3+}$) in acetonitrile(AN) and dimethylformamide(DMF) has been investigated by direct current, differential pulse polarography and cyclic voltammetry. The reduction of $La^{3+}$, $Pr^{3+}$ and $Nd^{3+}$ in 0.1M TEAP proceeded directly to the metallic state through three-electron charge transfer of irreversible process where as $Sm^{3+}$ and $Eu^{3+}$ proceeded by charge transfer of two steps. As the results of the cyclic voltammetric investigation, the first step reduction of $Sm^{3+}$ and $Eu^{3+}$ were a quasireversible reaction, the second step reductions were an irreversible reaction. The cathodic peak currents of the differential pulse polarogram showed adsorptive properties at lower sweep rates and high concentrations of these metal ions. The peak potenital was shifted to a negative petential and the peak current decreased with the increase of percentage of water in AN. On the other hand, the peak potential was shifted to a positive potential and the peak current decreased with an increased percentage of water in DMF.

• Journal of the Korean Applied Science and Technology
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• v.37 no.4
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• pp.830-838
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• 2020

The present study aimed to evaluate the effect of radiation mutant Perilla frutescens var. crispa on bone metabolism and the inflammatory response in a monosodium iodoacetateinduced rat model of osteoarthritis. radiation mutant Perilla frutescens var. crispa was administered orally at doses of 25, 50 or 100 mg/kg/day for 2 weeks before direct injection of monosodium iodoacetate (3 mg/50 μl of 0.9% saline) into the intra-articular space of the rats' right knees. The rats subsequently received the same doses of oral radiation mutant Perilla frutescens var. crispa for another 4 weeks. It was evaluated that the treatment effects based on serum biomarkers, and morphological and histopathological analysis of the knee joints. Compared with those in control rats, the radiation mutant Perilla frutescens var. crispa treatments significantly reduced the serum levels of inflammation, bone metabolism markers (i.e., COX-2, LTB4, MMP-3, and COMP), and the amount of fibrous tissue. Otherwise, it was significantly increased the concentration of TIMP-1 and calcitonin. In addition, the radiation mutant Perilla frutescens var. crispa treatments effectively preserved the knee cartilage and synovial membrane. As a result, it indicates that radiation mutant Perilla frutescens var. crispa prevented and alleviated osteoarthritis symptoms. Thus, radiation mutant Perilla frutescens var. crispa can be used in food and drug material for the management of osteoarthritis.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.1
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• pp.265-271
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• 2014

Interleukin-7 (IL-7) is a potent anti-apoptotic cytokine that enhances immune effector cell functions and is essential for lymphocyte survival. While it known to induce differentiation and proliferation in some haematological malignancies, including certain types of leukaemias and lymphomas, little is known about its role in solid tumours, including breast cancer. In the current study, we investigated whether IL-7 could enhance the in vivo antitumor activity of tumor-reactive $CD8^+$ T cells with induction of IFN-${\gamma}$ in a murine breast cancer model. Human IL-7 cDNA was constructed into the eukaryotic expression plasmid pcDNA3.1, and then the recombinational pcDNA3.1-IL-7 was intratumorally injected in the TM40D BALB/C mouse graft model. Serum and intracellular IFN-${\gamma}$ levels were measured by ELISA and flow cytometry, respectively. $CD8^+$ T cell-mediated cytotoxicity was analyzed using the MTT method. Our results showed that IL-7 administration significantly inhibited tumor growth from day 15 after direct intratumoral injection of pcDNA3.1-IL-7. The anti-tumor effect correlated with a marked increase in the level of IFN-${\gamma}$ and breast cancer cells-specific CTL cytotoxicity. In vitro cytotoxicity assays showed that IL-7-treatment could augment cytolytic activity of $CD8^+$ T cells from tumor bearing mice, while anti-IFN-${\gamma}$ blocked the function of $CD8^+$ T cells, suggesting that IFN-${\gamma}$ mediated the cytolytic activity of $CD8^+$ T cells. Furthermore, in vivo neutralization of $CD8^+$ T lymphocytes by CD8 antibodies reversed the antitumor benefit of IL-7. Thus, we demonstrated that IL-7 exerts anti-tumor activity mainly through activating $CD8^+$ T cells and stimulating them to secrete IFN-${\gamma}$ in a murine breast tumor model. Based on these results, our study points to a potential novel way to treat breast cancer and may have important implications for clinical immunotherapy.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.11
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• pp.483-490
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• 2016

Automobile door latch is a fine design and assembly techniques are required in order to produce them in a small component assembly shape such as a spring, injection products, a small-sized motor. The door latch is fixed to not open the door of the car plays an important role it has a direct impact on the driver's safety. In this study, during trimming of the terminals of the connector main components of the car door latch, reduce rollover and conducted a research to find a suitable effective shear surface. Using the Taguchi method with orthogonal array of Finite Element Analysis and optimal Design of Experiments were set up parameters for the shear surface quality of the car door latch connector terminals. The design parameters used in the analysis is the clearance, the radius, and the blank holding force, the material of the connector terminal is a C2600. Trimming process optimum conditions suggested by the analysis has been verified by experiments, the shear surface shape and dimensions of a final product in good agreement with forming analysis results.Taguchi method from the above results in the optimization for the final rollover and effective shear surface improved for a vehicle door latch to the connector terminal can be seen that the applicable and useful for a variety of metal forming processes other than the trimming process is determined to be applicable.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.993-994
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• 2008

Electrochromic (EC) devices are capable of reversibly changing their optical properties upon charge injection and extraction induced by the external voltage. The characteristics of the EC device, such as low power consumption, high coloration efficiency, and memory effects under open circuit status, make them suitable for use in a variety of applications including smart windows and electronic papers. Coloration due to reduction or oxidation of redox chromophores can be used for EC devices (e-paper), but the switching time is slow (second level). Recently, with increasing demand for the low cost, lightweight flat panel display with paper-like readability (electronic paper), an EC display technology based on dye-modified $TiO_2$ nanoparticle electrode was developed. A well known organic dye molecule, viologen, was adsorbed on the surface of a mesoporous $TiO_2$ nanoparticle film to form the EC electrode. On the other hand, ZnO is a wide bandgap II-VI semiconductor which has been applied in many fields such as UV lasers, field effect transistors and transparent conductors. The bandgap of the bulk ZnO is about 3.37 eV, which is close to that of the $TiO_2$ (3.4 eV). As a traditional transparent conductor, ZnO has excellent electron transport properties, even in ZnO nanoparticle films. In the past few years, one-dimension (1D) nanostructures of ZnO have attracted extensive research interest. In particular, 1D ZnO nanowires renders much better electron transportation capability by providing a direct conduction path for electron transport and greatly reducing the number of grain boundaries. These unique advantages make ZnO nanowires a promising matrix electrode for EC dye molecule loading. ZnO nanowires grow vertically from the substrate and form a dense array (Fig. 1). The ZnO nanowires show regular hexagonal cross section and the average diameter of the ZnO nanowires is about 100 nm. The cross-section image of the ZnO nanowires array (Fig. 1) indicates that the length of the ZnO nanowires is about $6\;{\mu}m$. From one on/off cycle of the ZnO EC cell (Fig. 2). We can see that, the switching time of a ZnO nanowire electrode EC cell with an active area of $1\;{\times}\;1\;cm^2$ is 170 ms and 142 ms for coloration and bleaching, respectively. The coloration and bleaching time is faster compared to the $TiO_2$ mesoporous EC devices with both coloration and bleaching time of about 250 ms for a device with an active area of $2.5\;cm^2$. With further optimization, it is possible that the response time can reach ten(s) of millisecond, i.e. capable of displaying video. Fig. 3 shows a prototype with two different transmittance states. It can be seen that good contrast was obtained. The retention was at least a few hours for these prototypes. Being an oxide, ZnO is oxidation resistant, i.e. it is more durable for field emission cathode. ZnO nanotetropods were also applied to realize the first prototype triode field emission device, making use of scattered surface-conduction electrons for field emission (Fig. 4). The device has a high efficiency (field emitted electron to total electron ratio) of about 60%. With this high efficiency, we were able to fabricate some prototype displays (Fig. 5 showing some alphanumerical symbols). ZnO tetrapods have four legs, which guarantees that there is one leg always pointing upward, even using screen printing method to fabricate the cathode.

• Environmental Mutagens and Carcinogens
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• v.9 no.1
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• pp.1-12
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• 1989

To study the selective organospecific carcinogenesis by the specific chemical carcinogens, the breast cancer induction model by oral administration of 7, 12-dimethylbenzanthracene (DMBA) or by intravenous injection of N-methylni-trosourea (NMU) on female rats was analyzed. In the present experiment, we compared the effexts of ages on the chemical mammary carcinogenesis by studying the metabolic system of the carcinogenic activation, detoxification or DNA damage and repair. The breast tumor incidence was significantly higher in the young rats of 50 days old than in those of one year old rats. As an index of organospecific DNA damage or repair, the in vivo covalent binding index(CBI) of the specific organs by the specific chemical carcinogens was monitored. And for the analysis of carcinogenic activation, the quantity of cytochrome P450`s was determined with the respective type-specific monoclonal antibody, while the detoxication capacity was deduced by the activity monitoring of glutathione S-transferase (GST) and peroxidase. The skin tissues of the mammary region had the highest CBI with both of DMBA and NMU at 50 days of age. And there were contrasting differences in the contents of carcinogenic activation and detoxication system: that is, the content of T.C.D.D.-inducible cytochrome P450 was high, while the activities of GST and peroxidase was low in the mammary skin tissues at tumor prevalent age. These results led us to conclude that the molecular organospecific carcinogenesis, as illustrated with mammary carcinoge-nesis by DMBA and NMU, is operated probably through the differential capacity of the target tissues in the high carcinogenic activation, low detoxication and the low DNA repair function.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.9
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• pp.1045-1050
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• 2014

$N_2O$(Nitrous Oxide) is known as the third major GHG(Green House Gas) following $CO_2$(Carbon Oxide) and $CH_4$(Methane). The GWP(Global Warming Potential) factor of $N_2O$ is 310 times as large as that of $CO_2$ because $N_2O$ in the atmosphere is very stable, and it becomes a source of secondary contamination after photo-degradation in the stratosphere. Investigation on the cause of the $N_2O$ formation have been continuously reported by several researchers on power sources with continuous combustion form, such as a boiler. However, in the diesel engine, research on $N_2O$ generation which has effected from fuel components has not been conducted. Therefore, in this research, author has investigated about $N_2O$ emission rates which was changed by nitrogen and sulfur concentration in fuel on the diesel engine. The test engine was a 4-stroke direct injection diesel engine with maximum output of 12 kW at 2600rpm, and operating condition of that was set up at a 75% load. Nitrogen and sulfur concentrations in fuel were raised by using six additives : nitrogen additives were Pyridine, Indole, Quinoline, Pyrrol and Propionitrile and sulfur additive was Di-tert-butyl-disulfide. In conclusion, diesel fuels containing nitrogen elements less than 0.5% did not affect $N_2O$ emissions in the all concentrations and kinds of the additive agent in the fuel. However, increasing of the sulfur additive in fuel increased $N_2O$ emission in exhaust gas.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.2
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• pp.217-224
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• 2012

In general, transportation sources include both on-road vehicles and off-road equipment. Off-road vehicles have usually used diesel engines, which have the disadvantage of high NOx emission. Common rail direct injection (CRDI) and after-treatment systems have been applied to meet the exhaust gas emission regulations for diesel vehicles. In the present, agricultural machinery has satisfied the Tier 3 emission regulations by using waste gate turbocharger (WGT) and internal exhaust gas recirculation (EGR). In this paper, the combustion and emission characteristics of an EGR system applied to a 56kW off-road vehicle in non-road transient cycle (NRTC) mode have been investigated. The EGR map was made from foundation experiments determining the EGR duty for all engine operating conditions, and then this map was applied to the NRTC mode. Consequently, the NOx emission was reduced by the EGR system, and the Tier 4 interim emission regulations were satisfied by using both the EGR system and an after-treatment system.