• Bulletin of the Korean Chemical Society
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• v.26 no.8
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• pp.1235-1240
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• 2005

A combination of electrospray ionization and tandem mass spectrometry was used to characterize the scavenging reactions of acrylamide (AA) in the presence of glutathione (GSH) in vitro. In the presence of GSH, AA was deactivated effectively and scavenged by reactions consuming small amount of GSH. Reaction products and structural information were identified using collision-induced dissociation (CID) in an ion trap mass spectrometer. In the mixture of GSH and AA, significant increase in abundance of fragment ion peak was observed at m/z 233, which was identified as $[Cys-Glu]^+$, formed by the elimination of glycine moiety of GSH. GSH also contributes to the AA scavenging reaction by conjugating with AA through the sulfhydryl group in cysteine moiety. The probable scavenging reaction pathway of AA in the presence of GSH has been proposed based on the CID experimental data.

• Molecules and Cells
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• v.42 no.3
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• pp.245-251
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• 2019

Ependymal cells constitute the multi-ciliated epithelium, which lines the brain ventricular lumen. Although ependymal cells originate from radial glial cells in the perinatal rodent brain, the exact mechanisms underlying the full differentiation of ependymal cells are poorly understood. In this report, we present evidence that the Anks1a phosphotyrosine binding domain (PTB) adaptor is required for the proper development of ependymal cells in the rodent postnatal brain. Anks1a gene trap targeted LacZ reporter analysis revealed that Anks1a is expressed prominently in the ventricular region of the early postnatal brain and that its expression is restricted to mature ependymal cells during postnatal brain development. In addition, Anks1a-deficient ependymal cells were shown to possess type B cell characteristics, suggesting that ependymal cells require Anks1a in order to be fully differentiated. Finally, Anks1a overexpression in the lateral wall of the neonatal brain resulted in an increase in the number of ependymal cells during postnatal brain development. Altogether, our results suggest that ependymal cells require Anks1a PTB adaptor for their proper development.

• Korean journal of applied entomology
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• v.41 no.4
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• pp.233-238
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• 2002

The seasonal occurrence trends of the brown-winged green bug, Plautia stali, and the brown malmorated stink bug, Halyomorpha halys, were monitored in sweet persimmon orchards in southern region of Korea using light traps (in 2000 and 2001), and aggregation pheromone traps (methyl (E, E, Z)-2 ,4, 6-decatrienoate)) of P. stali (in 2001). Light trap data showed that H. halys started to occur from the end of June, and reached its peak in early or mid August, while P. stali was mostly attracted to the traps from mid July to late August without any distinct attraction peak. Both species did not occur after September in the persimmon orchards studied. The attraction patterns of both species to aggregation pheromone traps were different from those observed in light traps. Both species were attracted to the pheromone traps from mid May to late August. The peak occurrence of H. halys could not be detected due to low catches. However, the period of peak attraction for P. stali was from late June to late August depending on the geographical locations. The aggregation pheromone traps of P. stali attracted more number of P stali than H. hails, but the light traps showed a reverse pattern. In both species, more females were attracted to the aggregation pheromone traps than males. The difference of attraction patterns between 2 types of traps was discussed in relation to content of soluble tannin in persimmon fruits.

• Korean journal of applied entomology
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• v.43 no.4 s.137
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• pp.281-289
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• 2004

The sex pheromone blend (28-12AC : E8-12AC : Z8-12OH = 95 : 5 : 1) of oriental fruit moth, Grapholita molesta (Busck), was evaluated with reference to its male attractivity at different dosage and lure longevity of 1.0 mg in a field condition. Also, degree-days (DD) were calculated up to major phenological events of G. molesta using seasonal adult flights monitored by pheromone traps and egg population densities in early season in Suwon peach orchards. In the range of 0.1-4.0 mg dosage examined, G. molesta males caught in pheromone trap decreased with increasing total pheromone doses. The highest number of G. molesta males were attracted in traps baited with 0.1 mg-lure, and there were no significantly differences among 0.5 to 4.0 mg-lure. In longevity test with a 1.0 mg-lure, there was no difference in mean numbers of G. molesta males caught between traps with fresh-baited lures every 20d and field-lasted lures up to ${\approx}50d$ after trap installation, but thereafter more G. molesta males were attracted in the field-lasted lures than in the fresh-baited lures. Accumulated degree-days (DD) from January 1 to the first adult emergence (biofix) were 39DD at a lower threshold temperature $8.1^{\circ}C$. Degree-days from the biofix up to the 1st adult peak through 4th peak were 98DD, 620DD, 1233DD, and 1916DD, respectively. Required degree-days from the 1st adult peak to the 1st egg peak were 130DD, while the 2nd egg peak timing was simultaneous with the 2nd adult peak. Further, management strategies of G. molesta were discussed in peach orchards.

• Korean journal of applied entomology
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• v.45 no.3 s.144
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• pp.309-316
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• 2006

Three sex pheromone components (cis-8-dodecenyl acetate (Z12Ac), trans-8-dodecenyl acetate (E12Ac), cis-8-dodecenol (Z12OH)) of the Oriental fruit moth, Grapholita molesta, were chemically synthesized. Especially to increase the composition of cis-stereoisomer, a triple bond intermediate was hydrogenated at $-20^{\circ}C$ with catalytic $Pd/BaSO_{4}$. The resulting product consisted of the acetates with a stereoisomer ratio in 92:8 (Z:E). The biological activity of the synthesized pheromone compounds was analyzed both in male responses and orientation disruption. The indoor pheromone effect was determined by male flight behavior showing wing movement in response to lure. Different mixtures of the synthetic pheromone components were prepared by mixing acetate and alcohol components in 100:0, 99:1, and 90:10 (g/g) and tested with a comparison of a standard commercial pheromone lure. The highest pheromone effect was observed in only acetate mixture (100:0) and the effect was reduced with the addition of the alcohol component. This indoor pheromone effect could be observed in field monitoring trial, in which 100:0 mixture showed the highest trap catches. Orientation disruption assay was conducted indoor by using a cage, in which the center had a commercial lure on sticky plate and the four candidates were placed at 6 cm away from the central lure on each of four directions. Test males were released to the arena during overnight (12 h) and then the caught males on the sticky plate were counted. The synthesized pheromone as well as the commercial pheromone showed 100% orientation disruption. However, the orientation disruption effect was reduced with decrease in the number of the surrounding disrupting pheromone baits. These results clearly suggest that the synthesized sex pheromone of G. molesta is biologically active and can be used for field mating disruption.

• Korean journal of applied entomology
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• v.44 no.4 s.141
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• pp.265-270
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• 2005

Seasonal occurrence of the stink bug Piezodorus hybneri (Gmelin) (Heteroptera: Penta-tomidae) was monitored at a soybean field and the campus of Gyeongsang National University, Gyeongnam. Korea, in which host plants are less available for the bug with aggregation pheromone traps of Riptortus clavatus Thunberg (Heteroptera: Alydidae) in 2004. At soybean field, P. hybneri began to be attracted to traps from June 28, earlier than flowering stage of soybean plants. Number of P. hybneri attracted increased sharply after October 11. At the campus the bugs were not attracted to traps from March 21 to October 5, but began to be attracted since October 11. Difference in the occurrences in the two sites may suggest that the stink bug immigrates actively into soybean field to find host plant. P. hybneri that had been attracted to traps since October 11 was assumed to be diapausing adults emigrating to hibernation sites. There was no difference between sexes in trap catches. The fact that P. hybneri was attracted from June to late November may suggest that the aggregation pheromone of R. clavatus was attractive to both non-diapausing and diapausing adults of P. hybneri. The aggregation pheromone traps, when baited with 16.7+16.7+16.7 mg or 7+36+7 mg of (E)-2-hexenyl (Z)-3-hexenoate, (E)-2-hexenyl (E)-2-hexenoate, and myristyl isobutyrate, attracted significantly higher number of both sexes of P. hybneri adults than the live male traps baited with ten R. clavatus males and hexane control.

• Korean journal of applied entomology
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• v.47 no.2
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• pp.141-147
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• 2008

Male adults of bean bug, Riptortus clavatus Thunberg (Heteroptera: Alydidae), release aggregation pheromone (AP) attracting both sexes of adult and nymphs, which its egg parasite, Ooencyrtus nezarae (Hymenoptera: Encyrtidae) exploits the pheromone to find host. The AP consists of three components; (E)-2-hexenyl (Z)-3-hexenoate (E2HZ3H), (E)-2-hexenyl (E)-2-hexenoate (E2HE2H), and tetradecyl isobutyrate (TI). We analyzed composition of the pheromone components of bean bugs from different geo graphical locations of Korea and Japan. The attractiveness of different blends of AP components to R. clavatus was also tested in the fields in Jinju, Korea and in Kumamoto, Japan. Composition ratios (E2HZ3H: E2HE2H:TI) of the AP of Jinju and Iksan populations were 1:1.4:0.2 and 1:0.8:0.2, and those of Tsukuba and Kumamoto populations were 1:2.8:0.2 and 1:1.5:0.1, respectively. In field tests, traps baited with ratio of 1:1:1 (E2HZ3H:E2HE2H:TI=16.7:16.7:16.7mg/rubber septum) and 1:1:0.5(E2HZ3H:E2HE2H:TI= 20:20:10mg/rubber septum) attracted significantly greater number of adult bugs than that of 1:5:1 (E2HZ3H:E2HE2H:TI=7.1:35.7:7.1mg/rubber septum).

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.12
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• pp.936-941
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• 2010

In this study, we have investigated the effects of Mn dopant on the bulk trap levels and grain boundary characteristics of $Bi_2O_3$-based ZnO (ZB) varistor using admittance spectroscopy and dielectric functions (such as $Z^*,\;Y^*,\;M^*,\;\varepsilon^*$, and $tan\delta$). Admittance spectra and dielectric functions show two bulk traps of $Zn_i^{..}$ (0.20 eV) and $V^{\bullet}_o$ (0.29~0.33 eV) in ZnO-$Bi_2O_3-Mn_3O_4$ (ZBM). The barrier of grain boundaries in ZBM could be electrochemically single type. However, its thermal stability was slightly disturbed by ambient oxygen because the apparent activation energy of grain boundaries was changed from 0.79 eV at lower temperature to 1.08 eV at higher temperature. The grain boundary capacitance $C_{gb}$ was decreased slightly with temperature as 1.3~1.8 nF but resistance $R_{gb}$ decreased exponentially. The relaxation time distribution can result from the heterogeneity of the barriers constituting the varistor. It is revealed that Mn dopant in ZB reduced the heterogeneity of the barrier in grain boundaries and stabilized the barrier against the ambient temperature.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.5
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• pp.368-373
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• 2010

In this study, we have investigated the effects of Cr dopant on the bulk trap levels and grain boundary characteristics of $Bi_2O_3$-based ZnO (ZB) varistor using admittance spectroscopy and dielectric functions (such as $Z^*,\;Y^*,\;M^*,\;{\varepsilon}^*$, and $tan{\delta}$). Admittance spectra show more than two bulk traps of $Zn_i$ and $V_o$ probably in different ionization states in ZnO-$Bi_2O_3-Cr_2O_3$ (ZBCr) system. Three kinds of temperature-dependant activation energies ($E_{bt}'s$) were calculated as 0.11~0.14 eV of attractive coulombic center, 0.16~0.17 eV of $Zn_{\ddot{i}}$, and 0.33 eV of $V_o^{\cdot}$ as dominant bulk defects. The grain boundaries of ZBCr could be electrochemically divided into two types as a sensitive to ambient oxygen i.e. electrically active one and an oxygen-insensitive i.e. electrically inactive one. The grain boundaries were electrically single type under 460 K (equivalent circuit as parallel $R_{gb1}C_{gb1}$) but separated as double one ($R_{gb1}C_{gb1}-R_{gb2}C_{gb2}$) over 480 K. It is revealed that the dielectric functions are very useful tool to separate the overlapped bulk defect levels and to characterize the electrical properties of grain boundaries.