• Journal of Ginseng Research
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• 제14권2호
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• pp.178-186
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• 1990

The analgesic effect of morphine was antagonized and the development of tolerance was suppressed by the modification of the neurologic function in the animals treated with ginseng saponins The activation of the spinal descending inhibitory systems as well as the supraspinal structures by the administration of morphine was inhibited in the animals treated with ginseng saponine intracerebrally or intrathecally. The development of morphine tolerance and dependence, and the abrupt expression of naloxone inducted abstinence syndrom were also inhibited by ginsenoside Rb1, Rb2, Rg1 and Re. These results suggest that ginsenoside Rbl, Hbs, Rgl and Re are the bioactive components of panax ginseng on the inhibition of the development of morphine tolerance and dependence, and the inhibition of abrupt abstinence sindrome. In addition, further research on the minor components of Pnnnxkinsenl should be investigated. A single or daily treatment with ginseng saponins did not induce any appreciable changes in the brain in level of monoamines at the variolls time intervals and at the various day intervals, respectively. The inhibitory or facilitated effects of ginseng saponins on electrically evoked contractions in guinea pig ileum ($\mu$-receptor) and mouse vats deferens ($\delta$-receptor) were not mediated through opioid receptors. The antagonism of a $\chi$ receptor agonist, U-50, 488H was also not mediated through opioid receptors in the animals treated with ginseng saponins, but mediated through serotonergic mechanisms. Ginseng saponins inhibited morphine 6-dehydrogenase which catalyzed the production of morphinone from morphine, and increased hepatic glutathione contents for the detoxication of morphinone. This result suggests that the dual action of the above plays an important role in the inhibition of the development of morphine tolerance and dependence.

• 한국농공학회지
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• 제45권7호
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• pp.57-69
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• 2003

To evaluate nutrient dynamics with different fertilization in paddy field and develop water quality model, mass balance analysis was performed during growing season of 2001-2002 in field experimental plots irrigated with groundwater. As a result of water balance analysis, most of outflow was surface drainage as about half of total outflow and about 500mm was lost by evapotranspiration. The water budget was well balanced. The runoff from paddy field was influenced by rainfall and forced drain. Especially runoff during early cultural periods more depends on the forced drain. As a result of mass balance analysis, most of nutrient was input by fertilization and lost by plant uptake. Significant amount of nitrogen were supplied by precipitation and input from upper paddy field, comprising 12%∼28% of total inflow. Nutrient loading by surface drainage was occurred showing about 15%∼29% for T-N and 6%∼13% for T-P. The response of rice yield with different fertilization was not significant in this study. Water quality model for paddy field developed using Dirac delta function and continuous source was calibrated and validated to surface water quality monitoring data. It demonstrates good agreement between observed and simulated. The nutrient concentration of surface water at paddy field was significantly influenced by fertilization. During early cultural periods when significant amount of fertilizer was applied, surface drainage from paddy field can cause serious water quality problem. Therefore, reducing surface drainage during fertilization period can reduce nutrient loading from paddy fields. Shallow irrigation, raising the weir height in diked rice fields, and minimizing forced surface drainage are suggested to reduce surface drainage outflow.

• Wind and Structures
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• 제23권6호
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• pp.615-639
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• 2016

Although the underlying mechanism of rain-wind induced vibrations (RWIVs) of stay cables has not been fully understood, some countermeasures have been successfully applied to mitigating this kind of vibration. Among these, installing dampers near the bridge deck was widely adopted, and several field observations have shown its effectiveness. In this study, the effectiveness of dampers to RWIVs of stay cables is numerically investigated comprehensively by means of finite difference method (FDM). Based on the free vibration analysis of a taut string, it is found that the 3-points triangle scheme, which can be easily implemented in FDM, can offer an excellent approximation of the concentrated damping coefficient (expressed as a Dirac delta function) at the location where the damper is installed. Then, free vibration analysis of a 3-D continuous stay cable attached with two dampers is carried out to study the relationship of modal damping ratio and damping coefficient of the dampers. The effects of orientation of the dampers and cable sag on the modal damping ratio are investigated in detail. Finally, the RWIV response of a 3-D continuous stay cable attached with two dampers is examined. The results indicate that 0.5% of damping ratio is sufficient to reduce the RWIV vibration of the Cable A20 on the No.2 Nanjing Bridge over Yangtze River.

• 한국항공우주학회지
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• 제31권2호
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• pp.1-9
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• 2003

본 연구에서는 비정렬 격자를 이용한 병렬화된 3차원 직접모사법을 개발하였다. 모사 입자의 추적에는 선형 형상 함수를 3차원으로 확장하여 적용하였다. 프로그램에서는 효율적인 병렬계산을 위하여 모사 입자의 수에 기초한 영역 재분할 방식을 이용하여 프로세서간의 작업 균형을 유지하였다. 밀도 차가 큰 두 개 이상의 유동이 동시에 존재할 경우를 효과적으로 모사하기 위해서 입자에 가중치를 적용하는 기법을 도입하였다. 프로그램의 검증을 위해서 3차원 삼각 날개 유동을 해석하여 실험치나 다른 계산 결과와 비교하였다. 또한 고도 100km의 희박한 환경헤서 우주발사체 탑재부 주의 유동을 해석하여 노즐 전방으로 고온의 풀룸이 역류하여 비행체 표면에 영향을 미칠 수 있는 가능성을 타진하였다.

• The Korean Journal of Physiology and Pharmacology
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• 제16권1호
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• pp.31-36
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• 2012

The receptor activator of NF-${\kappa}B$ ligand (RANKL) signal is an activator of tumor necrosis factor receptor-associated factor 6 (TRAF6), which leads to the activation of NF-${\kappa}B$ and other signal transduction pathways essential for osteoclastogenesis, such as $Ca^{2+}$ signaling. However, the intracellular levels of inositol 1,4,5-trisphosphate ($IP_3$) and $IP_3$-mediated cellular function of RANKL during osteoclastogenesis are not known. In the present study, we determined the levels of $IP_3$ and evaluated $IP_3$-mediated osteoclast differentiation and osteoclast activity by RANKL treatment of mouse leukemic macrophage cells (RAW 264.7) and mouse bone marrow-derived monocyte/macrophage precursor cells (BMMs). During osteoclastogenesis, the expression levels of $Ca^{2+}$ signaling proteins such as $IP_3$ receptors ($IP_3Rs$), plasma membrane $Ca^{2+}$ ATPase, and sarco/endoplasmic reticulum $Ca^{2+}$ ATPase type2 did not change by RANKL treatment for up to 6 days in both cell types. At 24 h after RANKL treatment, a higher steady-state level of $IP_3$ was observed in RAW264.7 cells transfected with green fluorescent protein (GFP)-tagged pleckstrin homology (PH) domains of phospholipase C (PLC) ${\delta}$, a probe specifically detecting intracellular $IP_3$ levels. In BMMs, the inhibition of PLC with U73122 [a specific inhibitor of phospholipase C (PLC)[ and of $IP_3Rs$ with 2-aminoethoxydiphenyl borate (2APB; a non-specific inhibitor of $IP_3Rs$) inhibited the generation of RANKL-induced multinucleated cells and decreased the bone-resorption rate in dentin slice, respectively. These results suggest that intracellular $IP_3$ levels and the $IP_3$-mediated signaling pathway play an important role in RANKL-induced osteoclastogenesis.

• 한국음향학회지
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• 제18권4호
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• pp.23-30
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• 1999

본 연구에서는 통과대역폭, 리플, 저지대역 감쇠도의 필터특성을 고려하여 주어진 입력사양에 부합하는 withdrawal SAW 필터의 새로운 최적화 알고리즘을 개발하고자 하였다. 필터의 성능해석을 위해 델타함수 모델을 이용하였으며, 대표적인 필터구조로서 균일한 입력 IDT에 대해 출력단을 withdrawal weighting하는 경우를 선정, 해석하였다. 이를 위해 여덟개의 설계변수를 선정하였으며 각각의 변화가 성능변수에 미치는 영향을 고려하여 세 단계를 거쳐 최적화 알고리즘을 완성하였다. 첫 단계에서는 삽입손실을 고려하여 입출력 전극수와 형상의 규격을 결정하고 다음 단계에서는 위상반전 방법을 이용하여 대역폭을 조절하며, 마지막 단계에서는 전극을 추가, 제거하는 방법을 통해 저지대역의 특성규격을 만족시켰다. 본 연구를 통해 제시하는 새로운 withdrawal weighting 필터 설계방법은 기존의 설계 방법들과는 달리 통과대역폭, 리플. 저지대역 억압도, 삽입손실 등의 필터특성을 동시에 고려하며 주어진 입력사양에 부합하는 필터를 최적화할 수 있다.

• 한국수산과학회지
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• 제47권5호
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• pp.671-681
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• 2014

The distribution and abundance of coastal fish species in Asan Bay, Korea, were estimated from hydroacoustic survey and net catches. Acoustic data were collected with 38 and 200 kHz from July to October of 2012, and converted to the nautical area scattering coefficient (NASC, $m^2/mile^2$) for $0.25n{\cdot}mile$ along ten transects. Japanese anchovy Engraulis japonicus was the dominant specie in the net catches. The virtual echogram technique was used to distinguish E. japonicus from other species based on the differences in the mean volume backscattering strength (${\Delta}MVBS$) at 38 and 200 kHz. Engraulis japonicus and other fishes are mainly distributed in the center channel and outer part of Asan Bay. E. japonicus tends to move from inner to outer Asan Bay in summer and fall. From NASC data, the target strength and length-weight function of E. japonicus and other fishes were used to estimate the E. japonicus stock at 24.1-93.3 tons, and other fish at 40.6-88.4 tons from July to October 2012. The estimated anchovy biomass compared well with the cumulative catch weight from stow net catches. The hydroacoustic method offers an approach to understanding spatial/temporal structure and estimating the biomass of fish aggregations in coastal areas.

• 한국전기전자재료학회논문지
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• 제13권6호
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• pp.472-477
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• 2000

Oxides of the form Mn$_{4}$/O$_{4}$-CuO-Co$_{3}$/O$_{4}$-NiO-ZnO present properties that make them useful as power NTC thermistor for current limited. Electrical properties of Mn$_{3}$/O$_{4}$-CuO-Co$_{3}$/O$_{4}$-CuO-Co$_{3}$/O$_{4}$-NiO-ZnO power NTC thermistor such as I-V characteristics tim constant activation energy and heat dissipation coefficient measured as a function of temperature and composition. In Mn$_{4}$/O$_{4}$-CuO-Co$_{3}$/O$_{4}$-NiO-ZnO system with the 5wt% addition of Co$_{3}$/O$_{4}$ it can be seen that resistivity and B-constant were increased as the ratio of ZnO/Mn$_{3}$/O$_{4}$ was increased. Heat dissipation constant, I-V characteristics and time constant showed similar behaviour compared with those of conventional thermistors. In particular resistance change ratio ($\Delta$R) the important factor for reliability varied within $\pm$5% indicating the compositions of these products could be available for power thermistor.

• Animal cells and systems
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• 제9권2호
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• pp.87-94
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• 2005

Spindle position checkpoint monitors the orientation of mitotic spindle for proper segregation of replicated chromosomes into mother cell and the daughter, and prohibits mitotic exit when mitotic spindle is misaligned. BUB2 forms one of the key upstream element of spindle position checkpoint in budding yeast, but its functional homologues have not been identified in higher eukaryotes. Here, we analyzed the functions of two putative BUB2 homologues of C. elegans in the spindle orientation checkpoint. From the C. elegans genome database, we found that two open reading frames (ORFs), F35H12_2 and C33F10_2, showed high sequence homology with BUB2. We obtained the expressed sequence tag (EST) clones for F35H12_2 (yk221d4) and C33F10_2 (yk14e10) and verified the full cDNA for each ORF by sequencing and 5' RACE with SL1 primer. The functional complementation assays of yk221d4 and yk14e10 in ${\Delta}bub2$ of S. cerevisiae revealed that these putative BUB2 homologues of C. elegans could not replace the function of BUB2 in spindle position checkpoint and mitotic exit. Our attempt to document the component of spindle position checkpoint in metazoans using sequence homology was not successful. This suggests that structural information about its components might be required to identify functional homologues of the spindle position checkpoint in higher eukaryotes.

• 마이크로전자및패키징학회지
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• 제20권4호
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• pp.25-30
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• 2013

Pb-free ferroelectric $(Na_{0.5}Bi_{0.5})TiO_3$ (NBT) thin films were prepared by a modified sol-gel process. Their structural, dielectric and pyroelectric properties were investigated as a function of the excess Na/Bi ratio and the annealing temperature. In the case of thin films containing no excess Na and Bi, only partial amounts of the perovskite NBT were crystallized, where the films consisted mainly of the pyrochlore phase of $Bi_2Ti_2O_7$ for annealing conditions of $600{\sim}800^{\circ}C$. With increasing excess Na/Bi ratio, the proportion of the perovskite phase effectively increased due to the compensation of the volatile Na and Bi components. For a Na/Bi ratio of 2.0, the thin film with single NBT perovskite phase was obtained within XRD detection limit after annealing at $700^{\circ}C$ for 10 min and it showed the excellent dielectric properties, ${\varepsilon}r$ of ~550 and tan ${\delta}$ of 0.03. While these properties were degraded for Na/Bi ratio of 2.5 despite the existence of pure perovskite phase. The NBT thin film with Na/Bi ratio of 2.0 are also promising candidates for applications requiring pyroelectric devices because it was found to have pyroelectric coefficients of $1.3{\sim}7nC/cm^2K$ in the temperature range of $30{\sim}100^{\circ}C$.