비감속 252Cf중성자선원에 대한 비등방성교정인자 및 선량당량환산인자

장시영,정덕연,윤석철,김종수 대한방사선 방어학회 1993 방사선방어학회지 Vol.18 No.2

중성자 측정장비 교정을 위한 표준중성자장을 제작하기 위하여 순수멕스월분포(kt=1.42MeV)로부터 ??Cf 자발핵분열 중성자선원의 밀봉이 교정인자에 미치는 영향을 고찰하였다. SR-Cf-100과 SR-Cf-1273 밀봉모형을 실제 제작조건으로 하여 MCNP 코드를 사용하여 몬테카를로 모의를 수행하여, 비등방성교정인자와 선속밀도-대-선량당량 환산인자를 산정하였고, 다른 연구결과와 비교하였다. 결과로서, Fi(θ=90˚)는 1.061(통계오차 : ±0.2%), H/??는 333.9[pSv·㎠] (통계오차 : ±0.5%)인 것으로 산정되었다. 이 환산인자(H/??)의 값은 ISO 8529의 권고보다 1.8%가 작은 것인데, 이것은 한국원자력연구소의 비감속 ??Cf중성자선원의 스펙트럼이 ISO의 것보다 약간 더 연화하다는 물리적 의미를 갖는다. Form the pure Maxwellian distribution(kT= 1.42MeV), the effects upon calibration factors of encapsulating a Cf spontaneous fission neutron source were invdwtigated to establish a standark neutron field in the Secondary Standark Kosimetry laboratory at Korea Atomic Inergy Research Institute(KAERI). A Monte Carlo code MCNP was used in simulating the encapsulation SR-Cf-100 and SR-Cf-1273 to be real conditions. The anisotropy(FI) and fluence-to-dose equivalents conversion factors(H/Φ) were evaluated and compared with other results. As the results, the FI was determined to be 1.061 atθ=90˚ with ±0.2% statistical error and the (H/Φ) was evaluated to be 333.9 [pSv·㎠] with ±0.5% statistical error, which is lower by 1.8% than that recommended by the ISO 8529. This means physically that the neutron spectrum of the unmoderated Cf source in KAERI is a little more softened than that by the ISO.

생태기후적(生態氣候的, bioclimatic) 디자인을 위한 건물의 외피구조(外皮構造)에 관한 연구

권시형,구본덕 영남대학교 공업기술연구소 1999 工業技術硏究所論文集 Vol.27 No.2

Bioclimatic design is one of the main strategies for sustainable Architecture, and is the emerging and remarkable issue from the viewpoint of worldwide energy crises and ecological problems Two catagories can be considered to study envelope system in Architecture as a bioclimatic design stratege ; the material aspects and the constructional aspects. Glass is one of the most popular materials for bioclimatlc envelope system. And we can consider five systems for constructional aspects ; single-skin facade system, double-skin facade system, multiful-skin facade system, trombwall assembly and water wall. And the effect of these systems and materials can be maximize when it used with other environmental factors and Architectural elements.

Screening of lethal genes for feeding RNAi by leaf disc-mediated systematic delivery in Tetranychus urticae

Deok Ho Kwon,Ji Hyeon Park,Si Hyeock Lee 한국응용곤충학회 2011 한국응용곤충학회 학술대회논문집 Vol.2011 No.10

The screening of effective lethal genes was conducted via the systemic delivery of dsRNA for the RNAi-based management of Tetranychus urticae. Six candidate genes (COPI coatmer, T_COPI; ESCRT III_Snf7, T_SNF7; Ribosomal protein S4, T_RPS4; v-ATPase A subunit 2, T_V-ATPase; Aminopeptidase N, T_APN3; Acetylcholinesterase, T_AChE) and two reference genes (EGFP and T_AChEintron) were tested for the experiment. The permeated dsRNA to the leaf disc (ca. 30 mm diameter) was detected at 6 h after treatment, indicating that dsRNA could move through veins on the leaf. In the reference gene selection, the T_AChEintron was chosen for its low mortality compared with EGFP gene. In the evaluation of mortality, the T_COPI, T_V-ATPase and T_RPS4 exerted higher toxicities at 24 hour after treatment among six genes tested. Interestingly, T_APN3 showed toxicity after 72 hour. In summary, the dsRNA delivery via leaf disc was effective in screening lethal genes and some genes, such as COPI, V-ATPase and RPS4, can be applicable for establishing a RNAi-based control system against T. urticae.

Species identification of Tetranychus urticae based on the molecular markers and morphological characters to establish an acaricide-susceptible strain

Deok Ho Kwon,Hyojoong Kim,Seunghwan Lee,Si Hyeock Lee 한국응용곤충학회 2009 한국응용곤충학회 학술대회논문집 Vol.2009 No.10

Acquisition of a reference Tetranychusstrains that are completely susceptible to acaricides and retain identical genetic backgrounds to acaricide-resistant strains is an essential step in elucidating mechanisms of resistance. To establish both completely susceptible and acaricide-resistant strains for this purpose, I collected Tetranychus mite populations from various regions in South Korea including both heavily cultivated and remote regions. Suitability as a susceptible or resistant reference strain was tested by determining species identity as Tetranychus urticae along with baseline susceptibility to common acaricides. The majority of mite populations collected from cultivated areas belonged to a monophyletic group of the previously reported green-type T. urticae as determined by mtCOI- and ITS2-based phylogenetic analysis. These strains showed relatively reduced levels of susceptibility to the acaricides tested, suggestive of the development of resistance. Among them, the AbaR strain was classified as a minor group in the T. urticae complex. The UD strain, originally collected from a remote island region, was found to be susceptible to the acaricides tested and generated an independent phylogenetic branch. The UD strain was also considered a minor group in the T. urticae complex. Phenotypic analysis based on morphological characters confirmed that both the AbaR and UD strains were statistically undistinguishable from the major green-type T. urticae. Taken together, I propose that the UD strain be used as a susceptible reference strain as it provides baseline susceptibility to acaricides and a wild-type genetic background for the resistance studies.

Multiple resistance mechanisms to abamectin in the two-spotted spider mite

Deok Ho Kwon,Si Hyeock Lee 한국응용곤충학회 2009 한국응용곤충학회 학술대회논문집 Vol.2009 No.10

The TSSM is one of the most destructive pests on various orchard trees and garden plants. Abamectin resistance mechanisms in two resistant TSSM strains (PTF, ca. 155-fold; AbaR, ca. 3700-fold) were investigated with an emphasis on target site insensitivity mechanism. Detoxification enzyme assays revealed that metabolic factors contributed by EST and/or P450are involved in abamectin resistance. Synergistic assays showed that enhanced detoxification enzyme activity is not enough to account for the high level of abamectin resistance, further suggestive of the involvement of additional resistance mechanism, most likely target site insensitivity. As a putative target site for abamectin, we cloned the cDNA fragments of glutamate-gated chloride channel (Tuglucl) and determined its full length nucleotide sequences. Amino acid sequence comparison among the four strains showed that the Gly323Asp mutation located in the third transmembrane domainis only found in the AbaR strain, suggesting it is likely associated with the target site insensitivity conferring a high level of abamectin resistance.

Quantitative sequencing method for the identification of acetylcholinesterase point mutations associated with monocrotophos resistance in Tetranychus urticae

( Deok Ho Kwon ),( Byung Ryul Choi ),( Si Woo Lee ),( Hyung Man Park ),( Si Hyeock Lee ) 한국응용곤충학회 2006 한국응용곤충학회 학술대회논문집 Vol.2006 No.9

The origin and evolutionary history of two insect acetylcholinesterases

Deok Jea Cha,Si Hyeock Lee 한국응용곤충학회 2013 한국응용곤충학회 학술대회논문집 Vol.2013 No.10

Acetylcholinesterase (AChE) plays a pivotal role in the synaptic transmission in the cholinergic nervous system of most animals, including insects. Insects have two different ace (ace1 and ace2) loci that encode two distinct AChEs (AChE1 and AChE2), which were originated by duplication events long before the radiation of insects. However, little is known about when the ace duplication occurred and how each duplicated ace locus has evolved to retain the original functions. In this study, we conducted phylogenetic analysis for cholinesterase genes from all the lower animals with their genome sequenced together with all known arthropod ace1 and ace2, including those from a number of insects that were newly cloned. Among several independent duplications in lower animal lineages, one duplication event found in platyhelminthes appeared to be the direct origin of arthropod ace1 and ace2. Comparison of the evolutionary distance (d) of two aces from different insect groups relative to those from common ancestors revealed that ace1 has evolved with a significantly slower rate compared to ace2, suggesting that the ace1 lineage has maintained relatively more essential functions following duplication. When the dN/dS ratio was compared between ace1 and ace2 within different insect orders, ace2 was determined to have received relatively more positive selection pressure in Diptera and Hymenoptera whereas the same was true for ace1 in Coleoptera, Hemiptera and Lepidoptera. Along with the relatively more decreased d value for ace2, such an increased dN/dS ratio for ace2 in Diptera and Hymenoptera implied the incidence of functional transition of ace1 to ace2. Our findings should provide with new insights into the evolution of two insect AChEs: when they were generated and how they retain and gain the neuronal functions.

Monitoring of carbamate and organophosphate resistance levels based on bioassay and quantitative sequencing in Nilaparvata lugens

Deok Ho Kwon,Si Woo Lee,Ji Hyeon Park,Si Hyeock Lee 한국응용곤충학회 2011 한국응용곤충학회 학술대회논문집 Vol.2011 No.10

The resistance levels against carbamates (CB) and organophosphates (OP) were determined through bioassay and quantitative sequencing (QS) methods in 16 field populations of Nilaparvata lugens. The resistance levels to CB and OP by bioassay were 1.3~47.5-fold and 1.4~14.4-fold higher than a susceptible strain, respectively. The QS protocol was established to determine the allele frequencies of eight point mutations on acetylcholinesterase putatively associated CB and OP resistance. The allele frequencies of four mutations in local populations (G119A, F/S330Y, F331H and I332L) ranged from ca. 0.0~51.7%, 1.0~44.3%, 8.5~57.3% and 7.12~56.6%, respectively. The average prediction limits were –9.6±5.1~7.7±2.9%. The F330Y, F331H and I332L were tightly linked each other, suggesting these mutations may occur simultaneously. In the correlation analysis, G119A was not well correlated with both insecticides (r2= less 0.25), whereas F/S330Y, F331H and I332L showed better correlation with the resistance levels of carbamate (r2=0.590) than organophosphate (r2=0.235). This finding indicates that F/S330Y, F331H and I332L mutation frequencies are suitable for detecting carbamate resistance in N. lugens. QS will be applicable for the rapid monitoring of resistance levels to CB insecticides in N. lugens.

Monocrotophos resistance in the two-spotted spider mite, Tetranychus urticae Koch, mediated by point mutation of acetylcholinesterase

Deok Ho Kwon,Si Hyeock Lee 한국응용곤충학회 2008 한국응용곤충학회 학술대회논문집 Vol.2008 No.10

Molecular mechanisms of monocrotophos resistance in the two-spotted spider mite (TSSM), Tetranychus urticae Koch, were investigated. The resistant (AD) strain showed ca. 3,565-fold resistance compared to a susceptible (UD) strain. No significant differences in the esterase and gluthathion-S-transferase activities were found between two strains whereas AD showed a 1.9-fold higher mixed function oxidase activity. Acetylcholinesterase (AChE) inhibition assay revealed that the AChE from AD strain is 91-fold less sensitive to monocrotophos, suggestive of the target site insensitivity mechanism. Three point mutations (G228S, A391T and F439W/Y) in the AChE gene (tssmace) appeared to primarily contribute to the reduced sensitivity of AChE as judged by the correlation study of mutation frequency versus resistance levels (LC50) of several field populations. The resulting correlation coefficients of the G228S and F439W mutations were 0.711 and 0.300, respectively, suggesting that G228S mutation may play a more significant role in resistance. The A391T mutation, saturated in all field populations examined, appears to provide a base line resistance.

Residual contact bioassay for the rapid diagnosis of acaricide resistance in Tetranychus urticae

Deok Ho Kwon,Jeong Joon Ahn,Joon Ho Lee,Si Hyeock Lee 한국응용곤충학회 2008 한국응용곤충학회 학술대회논문집 Vol.2008 No.10

To establish a rapid diagnosis method for the monitoring of acaricide resistance in the two-spotted spider mite, Tetranychus urticae, we evaluated the performance of residual contact vial (RCV) method as a routine bioassay for T. urticae by using two widely used acaricides, abamectin and tebupenpyrad. Appropriate concentrations of test acaricides were dissolved in acetone and evenly coated (100 μl) onto the inside wall of a 4-ml glass vial using a rolling machine. The average survival times in untreated control vial was longer than 12 hrs in the absence of food or water regardless of cap being closed or open. Webbing behavior of mites inside the vial, which may interfere with maximum chemical contact, began to be observed from 8 hrs post treatment. The minimum concentrations causing 100% mortality within 8 hrs posttreatment in a susceptible strain of T. urticae were determined to be 30 and 60 ppm in abamectin and tebupenpyrad, respectively. Dose-response curve was significantly affected by temperature in both acaricides, in which the knockdown rate increased greatly as temperature increased. The endpoint mortality at 6-8 hrs posttreatment, however, was not significantly affected by temperature. Nymphal stage of mites showed more rapid intoxication response than adults but endpoint mortality at 6-8 hrs posttreatment was not substantially different between developmental stages. When compared with the results from conventional spray method, RCV method showed moderate to high correlation coefficients (r=0.51~0.98), suggesting that it is a reliable in determining susceptibility of T. urticae. The vial-coated pesticides were stable at least one year when stored at -20°C as determined by LC-MS/MS analysis. Moreover, there was no significant difference in the bioassay results in repeated experiments with three different persons, indicative of high reproducibility of RCV. The RCV diagnostic kit, when used by farmers on site, should provide crucial and essential information for the selection of most suitable acaricides for different field populations of T. urticae.