• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.1396_1397
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• 2009

Recently, there has been considerable interest in electromagnetic pulse (EMP) source for no lethal directed energy weaponry applications. The compactness of the Marx generator, coupled with its ability to be powered by battery technology, makes it a viable handled impulse source. The marx generator has 2 stages. Each stage was constructed one charging capacitor, two electrodes and one charging resistor. A inductance structure is used in order to improve the switching performances fo the whole generator. The experiments of rise time in pure gas and mixtures of gases were described. The experimental results show that the rise time characteristics of the marx generator can be controlled through varying insulation gas.

• 한국양식학회지
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• 제12권2호
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• pp.115-122
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• 1999

Exposure experiments during the egg development were conducted to assess the influences of 5 different concentrations (0, 25, 50, 75 and 100%) of water-soluble fraction (WSF) of Kuwait crude oil on the eggs and larvae of black seabream (Acanthopagrus schlegeli), red seabream (Pagrus major) and olive flounder (Paralichthys olivaceus). All experiments were triplicated. Hatching time and hatching rate were examined on the eggs. The median lethal time ($LT_{50}$), morphological abnormality and swimming activity (swimming frequency and speed) of larvae were also investigated. The time and rate of egg hatching were not significantly influenced by WSF on the eggs of the fishes. The larvae exposed to WSF during the egg development were also not significantly influenced on the $LT_{50}$ and swimming activity. But the higher morphological abnormalities of notochord were observed from the larvae in 100% WSF exposure.

• 대한한의학회지
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• 제16권2호
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• pp.299-311
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• 1995

The studies were investigated in the coma time and the survival time induced by KCN, the duration of breathing after decapitation, the survival time following ligation of both common carotid arteries and the survival time after it is treated for normobaric bypoxia with a nitrogen gas, a carbon dioxide gas or a vaccum in mice. The results were as follows: 1. In histotoxic anoxia, Moschus(0.4mg／kg, p.o) demonstrated a protective effect on coma induced by a sublethal dose of KCN(1.8mg／kg, i.v.) in mice. 2. Mice subjected to a lethal dose of KCN(3.0mg／kg, i.v.) did not die by administration of Moschus. 3. Moschus was significantly extended the duration of breathing after decapitation in mice. 4. Moschus showed a significant extension of survival time in mice following ligation of both common carotid arteries. 5. In the normobaric hypoxia with a nitrogen gas, Moschus showed a significant extension of survival time in mice. 6. In the normobaric hypoxia with a carbon dioxide gas, Moschus showed a significant shortness of survival time in mice. 7. In the normobaric hypoxia with a vaccum, Moschus showed a significant extension of survival time in mice. From the above results, it is suggested that Moschus demonstrated protective effects on the brain damages induced by cerebral anoxia.

• Natural Product Sciences
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• 제17권4호
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• pp.309-314
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• 2011

Synthetic coumarin and furocoumarin derivatives were evaluated for anticoagulant activity and the effect on liver and kidney function. It was found that all of the compounds under investigation proved to be neither toxic nor lethal up to 500 mg/100 g body weight as a single dose for 24 hrs. All tested compounds showed a significant increase in prothrombin time (PT) in the acute model but failed to show a significant action in the chronic model. Furthermore, all tested compounds revealed a significant increase in activated partial thromboplastin time (APTT) as compared to control value in both acute and chronic model. Also, all tested compounds did not cause any significant changes on liver and kidney functions in rats.

• 방사선산업학회지
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• 제6권2호
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• pp.189-197
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• 2012

This study was carried out to develop the improved useful mutants for yield or composition of stevia plants using the gamma ray or chemical mutagens treatments. The seeds of stevia 'Suwon No. 11' were irradiated up to 400 Gy of gamma ray. Chemical mutagens were treated on the seeds of the 'Suwon No. 11' using 0.07% colchicine, 10 mM sodium azide, or 10 mM NMU for various durations. The germination rate, and shoot and root growth of seedling were estimated at 30 days after gamma ray irradiation or chemical mutagen treatment, and the plant height, the number of branches, and leaf length and width were examined at 3 months after mutagenesis treatments. In the case of gamma ray treatments, the germination rate and early-stage growth were decreased as the increase of radiation dose, and the 50% lethal dose was found to be 200 Gy. the plant height was decreased as the increase of radiation dose, while the number of branches per plant and leaf length were increased. Leaf shape was modified to the relatively longer one compared to the control, which was identified more apparently at the treatments of higher than 150 Gy. In the treatment of chemical mutagens, the rate of germination and survival were decreased as the increase of incubation time. The 50% lethal dose for germination rate were identified as the conditions of the 15 hours incubation in 0.07% colchicine, the 4 hrs in 10 mM sodium azide, and the 2 hrs in 10 mM NMU, in the three chemical mutagens treatments. Chemical mutagens had no influence on shoot growth, while root growth was increased, especially as the incubation time was extended. The highest root growth occurred in the NMU treatment at 6 hrs incubation time. The plant height was decreased as the increase of incubation time in the chemical mutagens treatments. Among the chemical mutagens, NMU was the most effective to induce the mutants with long-shaped or the least lobed leaves.

• BMB Reports
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• 제39권1호
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• pp.9-15
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• 2006

To prove whether error catastrophe /lethal mutagenesis is the primary antiviral mechanism of action of ribavirin against foot-and-mouth disease virus (FMDV). Ribavirin passage experiments were performed and supernatants of $Rp_1$ to $Rp_5$ were harvested. Morphological alterations as well as the levels of viral RNAs, proteins, and infectious particles in the BHK-21 cells infected using the supernatants of $Rp_1$ to $Rp_5$ and control were measured by microscope, real-time RT-PCR, western-blotting and plaque assays, respectively. The mutation frequency was measured by sequencing the complete P1- and 3D-encoding region of FMDV after a single round of virus infection from ribavirin-treated or untreated FMDV-infected cells. Ribavirin treatment for FMDV caused dramatically inhibition of multiplication in cell cultures. The levels of viral RNAs, proteins, and infectious particles in the BHK-21 cells infected were more greatly reduced along with the passage from $Rp_1$ to $Rp_5$, moreover, nucleocapsid protein could not be detected and no recovery of infectious virus in the supernatant or detection of intracellular viral RNA was observed at the $Rp_5$-infected cells. A high mutation rate, giving rise to an 8-and 11-fold increase in mutagenesis and resulting in some amino acid substitutions, was found in viral RNA synthesized at a single round of virus infection in the presence of ribavirin of $1000\;{\mu}M$ and caused a 99.7% loss in viral infectivity in contrast with parallel untreated control virus. These results suggest that the antiviral molecular mechanism of ribavirin is based on the lethal mutagenesis/error catastrophe, that is, the ribavirin is not merely an antiviral reagent but also an effective mutagen.

• 한국수산과학회지
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• 제19권6호
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• pp.599-607
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• 1986

Kuwait산 원유의 수용성 획분이 곤쟁이, Neomysis awatschensis의 폐사와 대사에 미치는 급성독성을 실험하였다. 본 실험은 지수식, 단기, 급성으로 표준생물검정법을 사용하였다. 폐사실험의 경우, 곤쟁이 성체를 대조구 포함 8개의 농도구에 폭로시켜서 반수치사농도($LC_{50}$)를 구했다. 96-hr $LC_{50}$을 총 탄화수소양으로 나타내면 $14^{\circ}C$에서는 1.01ppm, $20^{\circ}C$에서는 0.78ppm이었다. 반수치사시간($LT_{50}$)은 $14^{\circ}C$, 0.56ppm의 경우 100시간이었다. $20^{\circ}C$에서는 이보다 약간 앞당겨져 0.56ppm에서 95시간, 5.60ppm에서는 17시간이 경과하면서 $50\%$ 폐사에 도달했다. 대사실험의 경우, 농도간에 산소소비율의 감소가 크게 나타나지는 않았으나 전반적으로 대조구에 비해 뚜렷한 대사 감소를 보였고 동일농도에서 96시간이 48시간에 비해 더 낮은 대사율을 나타냈다. 이러한 실험결과, 저농도의 수용성 유류획분으로도 소형 해산 갑각류에 강한 독성을 미칠것이 예상된다.

• 한국응용곤충학회지
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• 제31권4호
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• pp.543-550
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• 1992

Buprofezin(25% WP)의 처리약량에 따른 벼멸구 유충에 대한 약효지속기간 및 buprofezin이 벼멸구 유충에 미치는 생물학적 영향을 폿트실험으로 조사하여 다음과 같은 결과를 얻었다. Buprofezin의 벼멸구 2령유충에 대한 약효지속효과는 상당히 길며, 처리농도가 높을수록 약효지속기간도 길었다. 17.5 g a.i./10 a 처리는 약처리 35일후에도 90%정도의 살충효과를 유지하였고, 5.78~11.50 g a.i./10 a 처리는 $RLT_{90}$(90% 이상 상충률을 유지하는 약처리후 경과시간)이 9.0~13.5일, $RLT_{50}$(50% 이상 살충률을 유지하는 약처리후 경과시간)은 16.8~22.8일로 추정되었다. 그리고 벼멸구 2령유충에 대하여 약처리 15일까지 95%이상의 살충력을 유지할 수 있는 buprofezin 처리약량은 13.00 g a.i./10 a이었고, 50%이상의 살충력을 유지할 수 있는 처리약량은 4.44 g a.i./10 a로 추정되었다. Buprofezin 7.0 g a.i./10 a 처리는 벼멸구 1령유충에 대하여 약처리 17일후까지 100%의 살충률을 유지하였으며 1령유충에 대한 $RLT_{50}$은 32.5일로 같은 농도의 2령 약충에 대한 $RLT_{50}$보다 15일정도 길었다. Buprofezin(7.0 g a.i./10 a)은 처리당시 4령까지의 유충을 100% 치사시켰고, 5령유충에 대해서는 우화전까지 약 70%의 살충력을 보였으나 5령이 생존하여 우화한 성충암컷은 수명이 현저하게 감소하였고 전혀 산란을 하지 못하였다.

• BMB Reports
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• 제38권1호
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• pp.41-48
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• 2005

In this study we developed the transposon-mediated shuttle vector 'Hanpvid', which composed of HaNPV (Heliothis armigera nuclear polyhedrosis virus) genomic DNA and a transposon cassette from Bacmid of Bac-to-Bac system. Hanpvid replicates in E. coli in the same way as Bacmid and retains infective function in cotton bollworm cells (Hz-AM1). Using Hanpvid we constructed a recombinant virus, which could infect Hz-AM1 cells and generate recombinant HaNPV (rHa-Bar) containing the barnase gene, a ribonuclease gene from Bacillus amyloliquefaciens. Since the expression vector carrying barnase gene cannot replicate in the absence of barstar, a specific inhibitor of barnase, we constructed a new cotton bollworm cell line (AM1-NB) using the marker rescue method. In AM1-NB barstar was integrated into the cellular chromosome to sustain the replication of rHa-Bar. To screen out recombinant HaNPV for potential use as biopesticide, Hz-AM1 and AM1-NB cell lines were infected with rHa-Bar, respectively. The results obtained indicate that Viral progenies in AM1-NB were 23 and 160 times greater than those in Hz-AM1 48 h and 72 h after infection, respectively. With additional insertion of the polyhedron gene from AcNPV (Autographa californica nuclear polyhedrosis virus) into the Hanpvid genome, rHa-Bar regained the polyhedron phenotype and its pest-killing rate greatly improved. Toxic analysis showed that the lethal dosages ($LD_{50}$) and the lethal time(s) ($LT_{50}$) of rHa-Bar were reduced by 20% and 30%, respectively, compared to wt-HaNPV in the third instar larvae of cotton bollworm. This study shows that in AM1-NB barnase can be effectively produced and used as pest-killing agent for the biological control of cotton pests.

• 동의생리병리학회지
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• 제18권2호
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• pp.586-595
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• 2004

Kamidojuk-San (KDJS) is known to be effective for treating cardiovascular diseases such hypertension, and clinically applied for the treatment of cerebral palsy or stoke patients. Yet, the overall mechanisms underlying its activity at the cellular levels are not known. Using experimental animal system, we investigated whether KDJS has protective effects on cells in cardiovascular and nervous systems. KDJS was found to rescue death of cultured primary neurons induced by AMPA, NMDA and kainate as well as BSO and Fe/sup 2+/ treatments. Moreover, KDJS treatment promoted animal's recovery from coma induced by a lethal dose of KCN treatment, and improved survival in animals exposed to lethal dose of KCN. Neurological examinations further showed that KDJS reduced the time which is required for animals to respond in terms of forelimb and hindlimb movements. To examine its physiological effects on cardiovascular and nervous systems, we induced ischemic injury in hippocampal neurons and cerebral neurons by middle cerebral artery (MCA) occlusion. Histological examination revealed that KDJS significantly protected neurons from ischemic damage. Thus, the present data suggest that KDJS may play an important role in protecting cells of cardiovascular and nervous systems from external noxious stimulations.