• Journal of Life Science
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• v.31 no.2
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• pp.144-148
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• 2021

This study aimed to analyze the content and composition of a biological amine, cadaverine, isolated from the venom of worker honeybees (Apis mellifera L.). This biological amine―which has diverse functionality, such as anti-inflammatory and antibacterial effects―has not been previously reported in bee venom. An assay completed in 13 minutes was developed for the cadaverine present in the bee venom using an ultra-performance liquid chromatograph and a Halo C18 column with acetonitrile and water as the mobile phase. The specificity, accuracy, and precision of the assay were verified, and the assay was validated. The linearity for cadaverine in the bee venom was R2=0.99 or above, indicating a moderate level. The limit of detection and limit of quantification were both 0.3 ㎍/ml, and the rate of recovery was 97.6%-99.1%. The relative standard deviation (RSD) of the intra-day precision and inter-day precision for cadaverine was 0.25%-0.44% and 0.25%-1.25%, respectively, with an RSD that fell within 5% indicating excellent precision. Through this novel assay, it was found that the mean content of cadaverine was 1.10±0.05 mg/g. Our results indicated that the linearity, limit of detection, limit of quantification, and rate of recovery of the cadaverine assay were of a satisfactory level, and the cadaverine content of the bee venom was ably determined. This study provides basic data on cadaverine in bee venom, which will prove useful in further studies on the bioactivity of this component.

• Korean Journal of Environmental Agriculture
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• v.28 no.3
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• pp.266-273
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• 2009

This study was conducted to develop more convenient simultaneous determination method by matrix solid phase dispersion (MSPD) and HPLC for sulfonamides such as sulfamerazine (SMR), sulfamethazine (SMT), sulfamonomethoxine (SMM), sulfadimethoxine (SDM), sulfaquinoxaline (SQX), and tetracyclines including oxytetracycline (OTC), tetracycline (TC) chlortetracycline (CTC) in prok and flatfish. The limits of detection were 0.047 $mg{\cdot}kg^{-1}$ for OTC, TC, SMR, SMT and SMM, and 0.033 $mg{\cdot}kg^{-1}$ for CTC, SDM, and SQX, respectively. So it is sufficiently possible to detect the eight tetracyclines and sulfonamides under their MRLs ($0.1{\sim}0.2mg{\cdot}kg^{-1}$). The average percentage recoveries of sulfonamides and tetracyclines from pig muscle and flatfish spiked standard solution were approximately $80.25{\sim}101.25%$ and $85.77{\sim}121.42%$, respectively. Therefore this method was efficient for simultaneous analysis of eight tetracyclines and sulfonamides.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2002.02a
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• pp.479-485
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• 2002

본 연구는 초음파를 이용하여 한우도체의 연도를 비파괴적이며 객관적으로 측정할 수 있는 시스템을 개발하기 위해서 수행되었다. 한우도체 연도 측정 시스템은 크게 초음파 측정장치, 자동 탐촉자 수직이동장치, 데이터 획득 및 분석장치로 구성되었는데 초음파 측정장치는 초음파 pulser/receiver 및 탐촉자, 자동 탐촉자 이동장치는 상하운동부, 구동부, 제어부, 데이터 획득 및 분석장치는 digitizer, Labview 5.1을 사용하여 구성되었다. 통합된 시스템을 이용하여 획득된 도체의 초음파 신호를 분석하기 위해 1.0~1.1 MHz의 bandpass filtering을 거쳐 hilbert 변환을 이용, envelope를 구할 수 있었으며 탐촉자와 도체의 최적 접촉 위치를 결정하기 위하여 3단계로 나누어 신호분석을 실시하였다. 시료의 개수는 40개였으며 획득된 envelope를 FFT 변환 후 PLS, PCR 분석을 수행한 결과 7단계의 PCR 분석에서 $R^2$= 0.6474의 유의성 있는 결과를 나타내었으므로 최적 접촉 위치로 결정하였다. 최적 접촉 위치를 통해 시료 80개의 추가 실험을 실시한 결과 PCR 분석에서 $R^2$= 0.4304의 결과를 나타내었으며 이를 이용, 도체의 연도를 측정하는 프로그램을 개발하고 최종 통합 시스템을 구축하였다. 본 한우도체 연도 측정 시스템의 개발을 통해 한우도체의 전단력을 예측하여 연도를 객관적으로 판정 가능할 것으로 생각되며 또한 사이즈의 확대로 도축장에 설치하는 설비로서 가능할 것이라 사료된다. 그러나 추후 좀 더 세밀한 측정과 결과의 보완을 위한 분석방법의 개선에 관한 연구가 진행되어야 할 것이다. 사용해 설계된 장치를 사용자가 쉽게 제작할 수 있도록 하였다. 공정설계프로그램을 통해 설계된 공정은 데이터베이스에 저장이 되며 장치설계프로그램에서 쉽게 이전에 설계했던 공정을 이용할 수 있도록 하여 공정 설계와 장치설계를 연계하도록 하였다.동투하시간과 비용 -종자준비부터 통마늘선별까지의 일관기계화로 투입된 주요작업의 노력은 75∼76%가 절감되고, 재배규모 3ha기준시 비용은 44-53%절감되었음. the annealing texture. Observations by TEM and EBSD revealed the formation of very fine grains of ∼1.0$\mu\textrm{m}$ after CCSS.he dislocations form local defect arrangements at the grooves permitting the substantial reduction in defect density over the remainder of the interfacial area.한 최대의 감자 재배지역을 형성하였다. 제주도는 산지지형과 따뜻한 기온으로 2기작이 가능하고, 감자가공 공장설립과 교통발달에 따른 육지 시장과의 접근이 용이해졌기 때문에 남한에서 2번째로 큰 감자재배지역이 되었다.(요약 및 결론에서 발췌)그람양성균에서 효과적이었으며, 농도별 항균력시험 결과 농도가 증가할수록 비례하여 저해율도 증가함을 알 수 있었다. 첨가농도를 달리하여 미생물의 생육도를 측정한 결과, fraction II磎꼭\ulcorner경우 그람양성균에 대해 500 ppm 이상에서 뚜렷한 증식억제효과를 나타내었다.서 뚜렷한 증식억제효과를 나타내었다.min/+}$계

• Analytical Science and Technology
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• v.18 no.2
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• pp.97-103
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• 2005

The various size and morphology microcapsules were prepared to produce smell sweet by heating condensation reaction of melamine and formaldehyde using 5-types of surfactants such as the laurylbenzenesulfonic acid sodium salt (SDS), polyvinylpyrrolidon (PVP), polyvinyl alcohol (PVA), Span-80 and 2-acrylamido-2-methyl-1-1 propanesulfonic acid (AMP). As result it was found that the size and morphology of microcapsule is intimately associated with a kind of surfactants. In order to prepare microcapsule with antibacterial, the silver nanoparticle was prepared by gamma-irradiation. microcapsule with silver nanoparticle was prepared.

• Education of Primary School Mathematics
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• v.17 no.3
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• pp.173-188
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• 2014

The aim of the case study presented in this paper was to explore mathematics curriculum knowledge of a South Korean elementary teacher. An in-depth case study is applied to examine mathematics curriculum knowledge that influences teachers' instructional process including analysis of diverse artifacts such as lesson plan, observation and interviews. Findings of this study suggest that mathematics curriculum knowledge has direct relevance to teaching a lesson, designing a lesson and assessing students' work. In addition, this study identified that mathematics curriculum knowledge may be divided into two sub-categories: vertical mathematics curriculum knowledge and horizontal mathematics curriculum knowledge. The results of this case study help our understanding of South Korean elementary teachers' mathematics curriculum knowledge, which has a deep impact on their teaching practice. Moreover, this cross-national research offers implications for researchers, policymakers, and teachers in U.S. as well as those in South Korea.

• Analytical Science and Technology
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• v.24 no.6
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• pp.493-502
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• 2011

The catalyst works for visible-light region was characterized. Toluene, xylene, MEK and ammonia were used as reactants. The decomposition efficiency was compared between visible-light photocatalyst and UV-light one. UV-photocatalyst can be activated with UV-light wave length of 280~360 nm. However, visible-light photocatalyst can be activated with visible wave length of 400~750 nm. This result was found by using UV-Vis absorbance. A lot of materials were doped to visible light photocatalyst in order to increase its performance. Platinum was added to visible light photocatalyst with manganese in order to increase performance of the visible light photocatalyst. MTMS (Methyl tri methoxy silane) was used as a binder. Contact angle was analyzed varying with amount of binder. Contact angle was increased with increasing the amount of MTMS. As a result, the hydrophilic property of photocatalyst with MTMS binder was decreased due to its hydrophobic one. And Mn-$TiO_2$ catalyst had an excellent anti-bacterial property.

• Korean journal of applied entomology
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• v.49 no.3
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• pp.251-259
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• 2010

A bacterial colony was isolated from the gut of the bean bug, Riptortus clavatus. From morphological and biochemical tests, the bacterial isolate showed the highest similarity to Staphylococcus succinus. DNA sequence of 16S rRNA gene of the bacterium supported the identification. Oral administration of penicillin G to adults of R. clavatus gave a dose-dependent mortality of adults of R. clavatus to adults along with significant decrease of the bacterial population in the gut. Similarly, three metabolites (benzylideneacetone, proline-tyrosine, and acetylated phenylalanine-glycine-valine) derived from an entomopathogenic bacterium, Xenorhabdus nematophila, also inhibited growth of the gut bacterial population and gave significant mortalities to R. clavatus. These results suggest that a gut bacterial population classified as Staphylococcus sp. is required for survival of R. clavatus and that the three bacterial metabolites had toxic effects on the bugs due to their antibacterial properties.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.2
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• pp.165-173
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• 1996

Large amounts (300 grams) of natural red tide plankton, Cochlodinium polykrikoides, was collected at the Yokji island coastal waters, Kyeongnam, Korea, on October, 1993. Using the bioassay systems, bioactive materials were screened from methanol extracts of C. polykrikoides. Live C. polykrykoides was toxic to fishes, however, the water soluble and chloroform soluble fraction of their methanol extracts did not shown ichthyotoxicity (5 mg/ml), and toxicity to mice (50 mg, i.p,). These fractions did not show any peaks corresponding to paralytic shellfish toxins or diarryhetic shellfish toxins on the fluorometric HPIC chromatograms. Neither fractions did not show antibiotic activities by paper disk (10 mg/disc) test and chloroform soluble fraction showed only $20\%$ growth inhibition activity on the Lymphoid P-388 at the concentration of $180\;{\mu}g/ml$. Hemolytic activity was detected by both fractions. Fatty acid analysis by GC, GC/MS and proton NMR showed that the chloroform soluble fraction composed of $25.3\%$ of DHA (dorosahexaenoic acid) and $15.3\%$ of IPA (eicosapentaenoic acid) as the hemolytic components.

• Journal of dental hygiene science
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• v.11 no.1
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• pp.37-40
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• 2011

Oleanolic acid (OA) and ursolic acid (UA) are triterpenoid compound present in many plants. This study examined the antimicrobial activity of OA and UA against Streptococcus downei. The antimicrobial activity was evaluated by the minimal inhibitory concentration (MIC) and time kill curves. The MIC values of OA and UA for S. downei isolated from the Korean population were $8{\mu}g/ml$. OA and UA had a bactericidal effect on S. downei ATCC $33748^T$ above $2{\times}MIC$, $16{\mu}g/ml$ and $8{\mu}g/ml$, respectively. The results suggest that OA and UA can be used in the development of oral hygiene products for the prevention of dental caries.

• Korean Journal of Food Science and Technology
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• v.42 no.5
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• pp.521-526
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• 2010

A high-performance liquid chromatography (HPLC) method was established for the determination of fluoroquinolones in milk. Protein was removed by using trichloroacetic acid in order to increase a mean recovery of milk. The extracts were using $Strata^{TM}$-X solid-phase extraction cartridge. The analytes were detected by HPLC on a $C_{18}$ column. HPLC method with fluorescence detection system (Ex: 278 nm, Em: 456 nm) provided a high degree of sensitivity in detecting fluoroquinolones. The limits of quantitation (LOQ) and mean recoveries of fluoroquinolones were 40 ${\mu}g$/kg and 73.6-95.2% (ofloxacin), 10 ${\mu}g$/kg and 77.3-91.9% (norfloxacin), 20 ${\mu}g$/kg and 91.6-94.3% (ciprofloxacin), 10 ${\mu}g$/kg and 81.0-87.8% (enrofloxacin), 10 ${\mu}g$/kg and 71.3-81.0% (sarafloxacin), 10 ${\mu}g$/kg and 89.4-90.8% (orbifloxacin), 2 ${\mu}g$/kg and 69.4-85.5% (danofloxacin).