• YAKHAK HOEJI
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• v.55 no.1
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• pp.49-55
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• 2011

Tumor necrosis factor-related apoptosis inducing ligand (TRAIL) is one of the promising anti-cancer agent because of its ability to selectively induce apoptosis in tumor cell lines but not in normal cells. However, TRAIL resistance has been reported in some cancer cells including hepatocarcinoma cells. Therefore, studies of agents that sensitize TRAIL-resistant cancer cells could be a effective therapeutic approach in cancer management. In our study, we examined the effect of combination of TRAIL with apigenin in human hepatocellular carcinoma cells. As a result, the combined use of TRAIL and apigenin significantly enhanced the cytotoxicity in PLC-PRF5 cells. Flow cytometry analysis after annexin V-FITC/PI dual staining showed that this increase of cell cytotoxicity was related to enhanced apoptosis in combined treatment of TRAIL with apigenin. Furthermore, synergistic induction of apoptosis was also confirmed by observation of morphological changes and annexin V-FITC/PI fluorescence. Our findings suggests that apigenin has the potential to improve the efficiency of TRAIL-based therapies in human hepatocellular carcinoma cells. Further study is needed to reveal the molecular mechanisms of this combined therapy.

• Journal of Welding and Joining
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• v.29 no.5
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• pp.95-98
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• 2011

Recently, there is a growing tendency that fine-pitch electronic devices are increased due to higher density and very large scale integration. Finer pitch printed circuit board(PCB) is to be decrease insulation resistance between circuit patterns and electrical components, which will induce to electrical short in electronic circuit by electrochemical migration when it exposes to long term in high temperature and high humidity. In this research, the effect of soldering flux acting as an electrical carrier between conductors on electrochemical migration was investigated. The PCB pad was coated with OSP finish. Sn3.0Ag0.5Cu solder paste was printed on the PCB circuit and then the coupon was treated by reflow process. Thereby, specimen for ion migration test was fabricated. Electrochemical migration test was conducted under the condition of DC 48 V, $85^{\circ}C$, and 85 % relative humidity. Their life time could be increased about 22% by means of removal of flux. The fundamentals and mechanism of electrochemical migration was discussed depending on the existence of flux residues after reflow process.

• Journal of Korean Biological Nursing Science
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• v.17 no.2
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• pp.179-187
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• 2015

Purpose: This study was done to evaluate the effects of a recreation therapy program on burn rehabilitation patients to determine if the program is an effective nursing intervention which can affect mental health problems and heart rate variability. Methods: Subjects were 54 hospitalized burn rehabilitation patients (25 in the control group, 29 in the experimental group). The experimental group participated 6 times in a recreation therapy program led by a qualified instructor. Brief symptoms inventory-18 (somatization, anxiety, depression) questionnaire, and heart rate variability were checked before and after the recreation therapy program. Results: The mental health scale showed significant differences in somatization (p<.001), anxiety (p<.001) and depression (p<.001). There was no significant difference in heart rate variability (autonomic activity, autonomic balance, stress resistance, stress parameter and fatigue, mean heart rate, electro-cardiac stability). Conclusion: The findings from this study suggest that a recreation therapy program is an effective nursing intervention to decrease the level of mental health problems of burn rehabilitation patients. However, a subsequent study is needed to develop an intervention program that will induce the effect of physiological parameters like heart rate variability (HRV).

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05b
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• pp.305-308
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• 2005

The sulfuric acid may react with the hardened cement paste and originate expansive products which can induce swelling and disaggregation of concrete. The purpose of this study is to estimate the antibacterial performance of antibiotics and the effect of absorbed condition of restorative mortar, the number of coating times and coating contents with antibiotic on the fundamental properties of restorative mortar spead with antibiotics. Also, testing items such as bonding strength, abrasion contents, contents of water absorption, contents of air permeability was tested to estimate the fundamental properties in this study. In results, the novellus bacillus inhabiting in sewer concrete structures was restrained by antibiotics developed in this study. And bonding strength of restorative mortar spread with antibiotics was similla to that of plain mortar. But, resistance to abrasion, water absorption and air permeability of restorative mortar spread with antibiotics was superior to that of plain mortar.

• Bulletin of the Korean Chemical Society
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• v.34 no.8
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• pp.2271-2275
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• 2013

We report on the photoelectrochemical properties of partially reduced mesoporous titania thin films. The fabrication is achieved by synthesizing mesoporous titania thin films through the self-assembly of a titania precursor and a block copolymer, followed by aging and calcination, and heat-treatment under a $H_2$ (1 torr) environment. Depending on the temperature used for the reaction with $H_2$, the degree of the reduction (generation of oxygen vacancies) of the titania is controlled. The oxygen vacancies induce visible light absorption, and decrease of resistance while the mesoporosity is practically unaltered. The photoelectrochemical activity data on these films, by measuring their photocurrent-potential behavior in 1 M NaOH electrolyte under AM 1.5G 100 mW $cm^{-2}$ illumination, show that the three effects of the oxygen vacancies contribute to the enhancement of the photoelectrochemical properties of the mesoporous titania thin films. The results show that these oxygen deficient $TiO_2$ mesoporous thin films hold great promise for a solar hydrogen generation. Suggestions for the materials design for improved photoelectrochemical properties are made.

• Nuclear Engineering and Technology
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• v.49 no.1
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• pp.71-81
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• 2017

When an integral pressurized water reactor is operated under low power conditions, once-through steam generator group operation strategy is applied. However, group operation strategy will cause nonuniform coolant flow distribution at the core inlet and lower plenum. To help coolant flow mix more uniformly, a flow mixing chamber (FMC) has been designed. In this paper, computational fluid dynamics methods have been used to investigate the coolant distribution by the effect of FMC. Velocity and temperature characteristics under different low power conditions and optimized FMC configuration have been analyzed. The results illustrate that the FMC can help improve the nonuniform coolant temperature distribution at the core inlet effectively; at the same time, the FMC will induce more resistance in the downcomer and lower plenum.

• Proceedings of the KOSOMBE Conference
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• v.1996 no.05
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• pp.133-136
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• 1996

We investigated how hydroxyapatite (HA) coating onto a porous super stainless steel (S.S.S, 22Cr-20Ni-6Mo-0.25N) affects bone ingrowth in a dog transcortical femoral model. Implants were histologically evaluated after 4 and 48 weeks of implantation, and the bone bonding strength at the bone/implant interface was examined by employing the pull-out test. The direct osseous tissue bonding onto the HA-coated S.S.S was observed, but the uncoated stainless steels had thin fibrous tissue layers. The mean interface strength of the HA-coated S.S.S was 1.5 and 2.5 times greater than those of the S.S.S and the 316L SS after one year of implantation, respectively. In preliminary studies, no toxic responce was observed from a cytotoxicity test of the S.S.S, having similar corrosion resistance to titanium. Our results suggest that early osteoconductive nature of HA coating may induce long term osteointegration for a bioinert substrate.

• Toxicological Research
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• v.12 no.1
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• pp.47-52
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• 1996

The renal toxicity of the extract of Polygalae Radix was investigated in rats. Rats were treated with 3.5 mg/Kg of the extract, i.p., for 7 days. Changes in consumatory behavior, 24 hour-urine and the activities of urinary enzymes were determined during the administration of the extract. Significant decrease in body weight and food consumption and increase in 24 hour-urine volume were observed during the administration. However, the quantity of total creatinine in urine was decreased significantly. Those indicate that subacute treatment with the extract might induce diuresis and the ditiresis might be due to the decrease in water reabsorption. In the activities of urinary enzymes, the activities of alanine aminopejotidase (AAP) and gamma-glutamyl transpeptidase (GGT) were increased 4.3 and 3.5 times and then returned to the control. The activity of N-acetyl-${\beta}$-D-glucosaminidase (NAG) was increased 7.2 times and then decreased slowly. But, it was significantly higher than that of the control evea after the last administration. The activity of factate dehydrogenase (LDH) was increased continuozlsly during the treatment. It showed 32 times higher than the control. These results suggested that the extract of Polygalae Radix had toxic effect on kidney. Furthermore, the result suggested that the subacute administration of the extract induced resistance against the toxicity of Polygalae Radix.

• Journal of Radiation Industry
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• v.4 no.3
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• pp.265-269
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• 2010

Silicon-based non-oxide ceramic carbide fiber is one of the leading candidate ceramic materials for engineering applications because of its excellent mechanical properties at high temperature and good chemical resistance. In this study, polycarbosilane(PCS) and zirconium butoxide were used as a precursor to prepare polyzirconocarbosilane (PZC) fibers. A polymer solution was prepared by dissolving PCS in zirconium butoxide (50/50 wt%). This solution was heated at $250^{\circ}C$ in a nitrogen atmosphere for 2 hour with stirring, and then dried in a vacuum oven for 48 hour. PZC fibers were fabricated using an electrospinning technique. The fibers were irradiated with an electron beam to induce structural crosslinking. Crosslinked PZC fibers were heat treated at $1,300^{\circ}C$ in a nitrogen atmosphere. The microstructures of PZC fibers were examined by SEM. Chemical structures of PZC fibers were examined by FT-IR and XRD. Thermal stability of PZC fibers was investigated by TGA.

• Journal of the Korean Society of Safety
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• v.34 no.3
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• pp.15-20
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• 2019

As industry is progressing and standards of living are improved, the demand of electrical energy is expected to grow 8-9% annually. Therefore, the importance of electrical fire prevention technology with the ability of the power supply is being emphasized. According to the statistics of fire in Korea, fire occurred about 45,000 cases annually, and electrical fire possessed about 20%. The electrical fire by poor contact has increased gradually, can be connected as great fire to secondarily induce short circuit and earth fault. Then analysis of heating causes of electrical connections between copper and copper alloy is needed. Also, detection and analysis algorithm of oxide at copper alloy are necessary. In this research, in order to understand the characteristics of oxide growth with rising resistance and heating, it is demonstrated that the oxide at electrical connections can cause fire due to arcing.