• Journal of Biosystems Engineering
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• 제32권3호
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• pp.153-159
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• 2007

This study was conducted to measure and analyze the noise from a combine head. The combine head, comprised of a cutting knife assembly, pick-up chains, horizontally conveying chains and vertically conveying chains, had an overall sound level of 101 dBA. The sound levels of each component were, respectively, 98.3 dBA for the cutting knife assembly, 88.9 dBA for the pick-up chains, 79.8 dBA for the horizontally conveying chains and 86.3 dBA for the vertically conveying chains, being equivalent to 54.4%, 18.4%, 6.5% and 13.7% of the overall head noise. The main cause of the head noise was considered the impacts that the joint of the cutting knife assembly made with frame when it oscillated. The impact sound was also generated when the chain lug collided with the chain case. To reduce these impact sound, anti-vibration rubbers were installed on the knife assembly joint and the chain cases. It reduced the head noise by 4 dBA but the overall noise level of the combine head was still high. In order to protect the combine operators more effectively from the noise, a safety cab needs to be installed on the combine.

• Clinical and Experimental Pediatrics
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• 제55권9호
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• pp.322-329
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• 2012

Purpose: Aeroallergens are important causative factors of allergic diseases. Previous studies on aeroallergen sensitization rates investigated patients groups that had visited pediatric allergy clinics. In contrast, we investigated sensitization rates in a general population group of elementary school to teenage students in Incheon, Jeju, and Ulsan. Methods: After obtaining parental consent, skin-prick tests were performed on 5,094 students between March and June 2010. Elementary school students were tested for 18 common aeroallergens, whereas middle and high school students were tested for 25 allergens. The 25 allergens included Dermatophagoides pteronyssinus, Dermatophagoides farinae, pollen (birch, alder, oak, Japanese cedar, pine, willow, elm, maple, Bermuda grass, timothy grass, rye grass, orchard grass, meadow grass, vernal grass, mugwort, Japanese hop, fat hen, ragweed, and plantain), and mold (Penicillatum, Aspergillus, Cladosporium, and Alternaria). Results: The sensitization rates in descending order were 25.79% (D. pteronyssinus ), 18.66% (D. farinae ), 6.20% (mugwort), and 4.07% (willow) in Incheon; 33.35% (D. pteronyssinus ), 24.78% (D. farinae), 15.36% (Japanese cedar), and 7.33% (Alternaria) in Jeju; and 32.79% (D. pteronyssinus), 30.27% (D. farinae), 10.13% (alder), and 8.68% (birch) in Ulsan. The dust mite allergen showed the highest sensitization rate among the 3 regions. The sensitization rate of tree pollen was the highest in Ulsan, whereas that of Alternaria was the highest in Jeju. The ragweed sensitization rates were 0.99% in Incheon, 1.07% in Jeju, and 0.81% in Ulsan. Conclusion: The differences in sensitization rates were because of different regional environmental conditions and distinct surrounding biological species. Hence, subsequent nationwide studies are required.

• Molecules and Cells
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• 제28권2호
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• pp.131-137
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• 2009

Plant defensins are small (5-10 kDa) basic peptides thought to be an important component of the defense pathway against fungal and/or bacterial pathogens. To understand the role of plant defensins in protecting plants against the brown planthopper, a type of insect herbivore, we isolated the Brassica rapa Defensin 1 (BrD1) gene and introduced it into rice (Oryza sativa L.) to produce stable transgenic plants. The BrD1 protein is homologous to other plant defensins and contains both an N-terminal endoplasmic reticulum signal sequence and a defensin domain, which are highly conserved in all plant defensins. Based on a phylogenetic analysis of the defensin domain of various plant defensins, we established that BrD1 belongs to a distinct subgroup of plant defensins. Relative to the wild type, transgenic rices expressing BrD1 exhibit strong resistance to brown planthopper nymphs and female adults. These results suggest that BrD1 exhibits insecticidal activity, and might be useful for developing cereal crop plants resistant to sap-sucking insects, such as the brown planthopper.

• 생약학회지
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• 제45권3호
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• pp.209-213
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• 2014

The anti-melanogenic substance was isolated from the root of Angelica gigas Nakai by silica gel column chromatography, preparative HPLC and TLC. As a result of the structure analysis by mass, $^1H$-NMR, and $^{13}C$-NMR spectrometry, the compound was identified as demethylsuberosin. Demethylsuberosin reduced melanin contents of B16F1 melanoma cells in a dose-dependent manner and decreased to about 74% at a concentration $5{\mu}g/ml$. Demethylsuberosin inhibited the expression in microphthalmia associated transcription factor (MITF), tyrosinase, tyrosinase related protein-1 (TRP-1), and tyrosinase related protein-2 (TRP-2) in melanocytes. These results suggest that the whitening activity of demethylsuberosin may be due to the inhibition of the melanin synthesis by down-regulation of MITF, tyrosinase, TRP-1 and TRP-2 expression. Thus, our results provide evidence that demethylsuberosin might be useful as a potential skin-whitening agent.

• 방사선산업학회지
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• 제5권3호
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• pp.231-236
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• 2011

'Ggoma' is a new Hibiscus dwarf type variety developed by gamma irradiation at the Korea Atomic Energy Research Institute (KAERI). This study was conducted to determine the best optimum cultural callus formation and shoot regeneration condition. Sterilized leaf tissues were cultured on MS (Marashige and skoog's) medium containing 3% sucrose, 0.8% agar with different concentration and combination of TDZ, 2, 4-D, KT, BA, and 2iP for 4 weeks in vitro culture. MS medium containing 2,4-D $0.1mg\;l^{-1}$ and BA $0.5mg\;l^{-1}$ were most effective on callus formation and growth. After 4 weeks, callus was transferred on BA (0.5, 1, $1.5mg\;l^{-1}$) and TDZ (0.1, 0.2, $0.3mg\;l^{-1}$) for shoot formation. The best condition for inducing the shoot from callus was BA $1.5mg\;l^{-1}$ and TDZ $0.3mg\;l^{-1}$. This result will be useful for the rapid multiplication of Hibiscus syriacus L.var. Ggoma.

• 대한환경공학회지
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• 제36권4호
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• pp.258-264
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• 2014

본 연구는 낙동강 중류수계의 강정고령보와 달성보의 수질특성을 조사하였다. 조사결과 강정고령보와 달성보에서 COD 3.5~6.8 mg/L, TOC 3.4~6.5 mg/L, T-N 1.8~4.0 mg/L, T-P 0.08~0.12 mg/L의 농도로 조사되었으며, 달성보에서 다소 높은 농도로 조사되어 금호강 유입의 영향이 큰 것으로 판단된다. 침전물 조사결과 강정고령보와 달성보에서 모두 심층의 SS, T-N, T-P 수질지표의 농도가 표층의 1.6~2.4배로 높게 조사되었으며, 침전율(%/d)은 표층에서 7.14~9.76 %/d, 심층에서 1.68~2.42 %/d로 다소 낮게 침전되는 것으로 조사되어 심층의 SS가 쉽게 가라앉지 않고 부유하고 있는 경향을 나타냈다. 용출조사에서는 시간이 지날수록 용출농도가 증가하여 나타났으며 수온과 DO농도와 밀접한 관계가 있는 용출 특성에 의해 하계의 높은 수온과 낮은 DO농도의 조건이 용출에 용이 했을 것으로 판단된다.

• 한국수정란이식학회지
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• 제29권3호
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• pp.207-219
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• 2014

Three-dimensional (3D) culture system is useful technique for study of in vivo environment and it was used various experiments. This study was investigated to establish of embryo co-culture system and changes of PAs activity in 3D cultured endometrial cells of pigs. In results, growth of stromal cells into gel matrix were detected only with endometrial and myometrial cells. The most rapid growth of stromal cells were confirmed in $2.5{\times}10^5cells/ml$ and gel matrix containing 15% FBS. Expression of urokinase-PA (uPA) after treatment of hCG (0.5, 1.0, 1.5 and 2.0 IU/ml) were higher than without hCG, but, there are not significant difference among the treatment. On the other hand, expression of uPA after treatment of $IL-1{\beta}$ (0.1, 1, 10 and 100 ng/ml) were higher than without $IL-1{\beta}$, but, there are not significant difference. Expression of uPA after treatment of estrogen (0.2, 2, 20 and 200 ng/ml) were not difference, but PA activity was significantly decreased (p<0.05). Blastocyst was producing in PZM-3 medium containing FBS and endometrial cells were grown in PZM-3 medium. When embryos development with cultured endometrial cells, cleavage rates were not significant difference and blastocyst were not produced in co-culture with stromal cells and 3D culture system. 3D culture system had similar activity to in vivo tissue and these features are very useful for study of in vivo physiology. Nevertheless 3D culture system was not proper in embryo co-culture system. Therefore, we suggest that 3D culture system with embryo co-culture need continuous research.

• Archives of Pharmacal Research
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• 제28권5호
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• pp.529-533
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• 2005

In the course of searching for hepatoprotective agents from natural products, six compounds were isolated from the MeOH extract of the leaves of Juglans sinensis, as guid ed by their DPPH free radical scavenging activity. The structures were determined as juglanoside B (1), quercetin 3-O-${\alpha}$-L-arabinofuranoside (avicularin, 2), quercetin 3-O-${\alpha}$-L-arabinopyranoside (guaijaverin,3), quercetin 3-O-${\alpha}$-L-rhamnopyranoside (quercitrin,4), (+)-catechin (5) and quercetin 3-O-${\beta}$- D-galactopyranoside (hyperin,6). Compounds 2-6 showed significant DPPH free radical scavenging effects. An evaluation for the hepatoprotective activity of the isolated compounds on drug-induced cytotoxicity was conducted, and compounds 1, 2, and 5 showed protective effects against nitrofurantoin-induced cytotoxicity, and compound 5 also exhibited a moderate protective effect on amiodarone-induced cytotoxicity in Hep G2 cells.

• 대한전자공학회논문지SD
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• 제43권10호
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• pp.111-117
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• 2006

다중모드/다중대역 무선 통신 수신기에 사용할 수 있는 재구성 가능한 CMOS 저잡음 증폭기를 개발하였다. 입력단에 common-gate 트랜지스터 회로를 사용함으로써 출력단의 impedance 만을 조절하면 여러 주파수 대역에서 최적의 특성을 갖도록 하였다 통상적인 common-gate 형태의 저잡음 증폭기는 3dB 이상의 높은 잡음 지수를 갖는데, 부귀환 회로를 사용하여 2dB 이하의 잡음 지수를 갖도록 하였다. 무선 수신기의 선형성 특성을 최적화할 수 있도록 저잡음 증폭기의 전압 이득을 조절 할 수 있도록 하였다. 0.13mm CMOS 공정을 이용하여 개발하였으며 $1.8{\sim}2.5GHz$ 대역에서 전압 이득은 $19{\sim}20dB$, 잡음 지수는 $1.7{\sim}2.0dB$, third-order input intercept point (IIP3)는 -2dBm이다. 1.2V의 공급 전압에서 7mW의 전력을 소모한다.

• 한국가금학회지
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• 제39권4호
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• pp.311-315
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• 2012

The increasing demand for Korean native chicken meat indicates that the discovery of haplotypes is very important from both economic and conservation points of view. In this study, mtDNA D-loop sequences from two crossbred Korean native chicken populations of 138 individuals were investigated. Twenty six nucleotide substitutions were identified from sequence analysis and were classified into 12 haplotypes. The haplotype H_8 represents 73.47% of Woorimatdag (chicken population) sequences, which were identified in all five Woorimatdag chicken populations investigated. The H_7 haplotype (Dhap1) for D population covers 45% sequences, which indicate maternal inheritance from black Korean native chicken. On the other hand, Chap3 and Chap4 for C population are specific haplotypes, as H_5 and H_2, respectively. Based on the network profiles, six SNPs (C199T, A239G, G242A, A291G, T330C and C391A) of the D-loop region are effective markers for discrimination between Woorimatdag and Hanhyup chicken populations. Also, the phylogenetic analyses of Woorimatdag and Hanhyup chicken populations were used to identify the genetic relationships among the haplotypes. The results presented here can be used for developing molecular markers to discriminate between two commercial Korean native chickens.