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        검색결과 237

        1.
        2023.05 구독 인증기관·개인회원 무료
        The radiolytic decomposition of oxalic acid was investigated using gamma irradiation for decontamination of nuclear power systems. The study used high-purity analytical grade chemicals, with initial concentrations of oxalic acid prepared at 1, 2, 5, and 10 mM, and the initial pH was adjusted to 2-3 at each test condition. Gamma irradiation was performed using a high-level Co-60 source, and absorbed doses were 5, 10, 20, 30, and 50 kGy. The results showed that the efficiency of gamma irradiation decreased with longer gamma exposure time, and the G-value increased with the initial concentration of oxalic acid. Interestingly, the G-value decreased with accumulated radiation dose, but the removal increased. The dose constant ranged from 0.1695 to 0.0536 kGy-1 at different initial concentrations, and the G-value was inversely proportional to the dose constant. The study concluded that oxalic acid was successfully degraded by gamma irradiation, and 92% removal was obtained at the initial concentration of 10 mM. The mineralization of oxalic acid at higher concentrations was more difficult due to the great number of generated intermediates.
        4.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        North Korea continues to upgrade and display its long-range rocket launchers to emphasize its military strength. Recently Republic of Korea kicked off the development of anti-artillery interception system similar to Israel’s “Iron Dome”, designed to protect against North Korea’s arsenal of long-range rockets. The system may not work smoothly without the function assigning interceptors to incoming various-caliber artillery rockets. We view the assignment task as a dynamic weapon target assignment (DWTA) problem. DWTA is a multistage decision process in which decision in a stage affects decision processes and its results in the subsequent stages. We represent the DWTA problem as a Markov decision process (MDP). Distance from Seoul to North Korea’s multiple rocket launchers positioned near the border, limits the processing time of the model solver within only a few second. It is impossible to compute the exact optimal solution within the allowed time interval due to the curse of dimensionality inherently in MDP model of practical DWTA problem. We apply two reinforcement-based algorithms to get the approximate solution of the MDP model within the time limit. To check the quality of the approximate solution, we adopt Shoot-Shoot-Look(SSL) policy as a baseline. Simulation results showed that both algorithms provide better solution than the solution from the baseline strategy.
        4,200원
        10.
        2022.04 구독 인증기관·개인회원 무료
        14.
        2021.03 구독 인증기관 무료, 개인회원 유료
        Demethoxycurcumin (DMC), which is a curcuminoid found in turmeric, has anti-proliferative effects on cancer cells. However, the effect of DMC on osteosarcoma has not been established. The aim of this study was to examine the effects of DMC on cell growth and apoptosis induction in MG-63 human osteosarcoma cells. This study was investigated using 3-[4, 5-dimethylthiazol-2-yl]-2, 5 diphenyl tetrazolium bromid assay, Live/Dead cell assay, 4’, 6-diamidino-2-phenylindole staining, and immunoblotting in MG-63 cells. DMC induced MG-63 cell death in a dosedependent manner, with an estimated IC50 value of 54.4 μM. DMC treatment resulted in nuclear condensation in MG-63 cells. DMC-induced apoptosis in MG-63 cells was mediated by the expression of Fas and activation of caspase-8, caspase-3, and poly (ADP-ribose) polymerase. Immunoblotting results showed that Bcl-2 and Bcl-xL were downregulated, while Bax and Bad were upregulated by DMC in MG-63 cells. These results indicated that DMC inhibits cell proliferation and induces apoptotic cell death in MG-63 human osteosarcoma cells via the death receptormediated extrinsic apoptotic pathway and mitochondria-mediated intrinsic apoptotic pathway.
        4,000원
        15.
        2021.03 구독 인증기관 무료, 개인회원 유료
        Alpha-lipoic acid (ALA) is a naturally occurring antioxidant and has been previously used to treat diabetes and cardiovascular disease. However, the autophagy effects of ALA against oxidative stress-induced dopaminergic neuronal cell injury remain unclear. The aim of this study was to investigate the role of ALA in autophagy and apoptosis against oxidative stress in the SH-SY5Y human dopaminergic neuronal cell line. We examined SH-SY5Y phenotypes using the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay (cell viability/proliferation), 4′,6-diamidino-2-phenylindole dihydrochloride nuclear staining, Live/Dead cell assay, cellular reactive oxygen species (ROS) assay, immunoblotting, and immunocytochemistry. Our data showed ALA attenuated hydrogen peroxide (H2O2)-induced ROS generation and cell death. ALA effectively suppressed Bax up-regulation and Bcl-2 and BclxL down-regulation. Furthermore, ALA increased the expression of the antioxidant enzyme, heme oxygenase-1. Moreover, the expression of Beclin-1 and LC-3 autophagy biomarkers was decreased by ALA in our cell model. Combined, these data suggest ALA protects human dopaminergic neuronal cells against H2O2-induced cell injury by inhibiting autophagy and apoptosis.
        4,000원
        16.
        2020.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigated the substitution effect of phosphate and isolated soybean powder (ISP) by Allomyrina dichotoma larvae powder (AP) in emulsion sausage. The sausages were prepared for five treatments: 1) positive control (PC): sausages manufactured with sodium pyrophosphate (0.3%) and ISP (1%); 2) negative control (NC): sausages manufactured without sodium pyrophosphate, and ISP; 3) phosphate replacement (PR): sausages manufactured with ISP and AP (1%); 4) ISP replacement (IR): sausages manufactured with sodium pyrophosphate and AP; 5) phosphate and ISP replacement (PIR): sausages manufactured with AP. The 1% AP extract showed DPPH radical scavenging (45.65±2.468%) and metal chelating (22.46±3.559%) activity. The high pH value of AP (8.03) increased the pH of the meat batter of PR, IR, and PIR (p<0.05), but there was no inhibitory effect on cooking loss. Cooking loss of IR was not significantly different with PC due to phosphate. The addition of AP decreased the L* and a* values and increased the b* values, and decreased hardness, chewiness, and springiness of PR, IR, and PIR (p<0.05). AP did not inhibit lipid oxidation in sausages, in contrast to phosphate. In sensory evaluation, the addition of AP resulted in low scores for all sensory parameters of the sausages, although most panels had normal or positive awareness (p<0.05). Aroma was more influential on samples than color. Overall, AP did not replace phosphate and ISP in the sausages. Therefore, processes such as eliminating unique aroma and color and increasing solubility through particle size control are necessary to use AP as a protein source.
        4,200원
        19.
        2020.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The carbon anode material for lithium-ion battery was prepared by pyrolysis fuel oil and waste polyethylene terephthalate (PET) additive. The pitch was synthesized as a medium material for carbon anode by heat treatment. The waste PET additive improved the softening point and thermal stability of the pitch. La and Lc of the anode material (heat-treated pitch) increased at higher treatment temperature but decreased by waste PET additive. The electric capacity was evaluated based on effects of defective cavity and developed graphite interlayer, respectively. When the La and Lc of the anode material decreased, the electric capacity by cavity increased based on defective graphite structure. Therefore, the addition of waste PET causes the improved capacity by the cavity. The anode material which has a high efficiency (over 95%) and C-rate (95%, 2 C/0.1 C) was obtained by controlling the process of heat treatment and PET addition. The mechanism of lithium-ion insertion was discussed based on effects of defective cavity and developed graphite interlayer.
        4,000원
        20.
        2020.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        벼의 잎은 광합성을 위한 주요 기관으로, 동화산물의 생산을 통해 벼의 수량 결정에 영향을 준다. 따라서, 상위엽의 형태적 특징은 다수성 벼 품종의 육성을 위한 필수적인 고려요소이다. 본 연구에서는, 연차간 안정적으로 발현하는 3개의 엽폭 조절 QTL인 qLW4.1, qLW4.2, qLW7을 탐지하였다. 이들은 분석집단에서 나타난 엽폭 표현형 변이의 5.2~44.9% 를 설명할 수 있었다. qLW4.2 영역에 대한 후보유전자 분석 결과, 해당 QTL 영역에서 엽폭 조절 유전자인 NAL1을 발견하였다. 상위엽은 수량에 대해 정의 간접효과 나타냈으며, 그 효과의 크기는 수당립수에 대한 상위엽의 정의 직접효과와 수수에 대한 상위엽의 부의 직접효과에 의해 결정되었다. 한국 벼 유전자원에서 엽폭은 상대적으로 좁은 범위에서 표현형 변이를 나타내었으며, 이는 특정 상위엽폭이 한국 자원에서 선호 되었음을 시사한다. NAL1의 하플로타입 분석결과는 대다수의 한국 자원들이 자포니카형 하플로타입을 지닌 반면에, 모든 통일형 품종들은 인디카형을 지니고 있음을 밝혀냈다. 이러한 결과는 유용 대립유전자형인 자포니카형 NAL1의 도입을 통해 통일형 품종의 다수성 형질을 더욱 향상시킬 수 있음을 의미 한다.
        4,000원
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