• 미생물학회지
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• 제46권4호
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• pp.389-396
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• 2010

살충성 독소 결정을 생산하는 Bacillus thuringiensis BT17 균주를 분리하였으며, 16S rRNA 유전자 분석 결과 B. thuringiensis serovar colmeri로 동정하였다. BT17 균주는 인시목 유충에 대해 살충성을 보이는 결정성 독소를 soybean meal과 skim milk를 포함하는 배지에서 $30^{\circ}C$, 280 rpm으로 36시간 진탕배양하였을 때 효율적으로 생산하였다. 200 L fermentor에서 배양하였을 때 균수는 24시간에 최대가 되었으나 독소 결정의 수는 36시간까지 증가하였다. 액상의 미생물 살충제 제품을 제조하였으며, 배양액을 $20^{\circ}C$에서 3개월간 보관시 독소 결정의 수는 보관 초기보다 2배까지 증가하였다. BT17 균주가 포함된 살충제 제품의 효능은 파밤나방보다 배추좀나방에서 좋았으며 동물에 대한 독성은 거의 없었다.

• 한국미생물·생명공학회지
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• 제14권3호
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• pp.209-212
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• 1986

YEp 13 plasmid에 B. amyloliquefaciens의 $\alpha$-amylase gene을 cloning시켜서 얻은 hybrid plasmid를 E. coli C 600으로 형질전환시켜서 amylase 활성을 나타내는 균주를 선별하였다. 선별된 E. coli C 600균주를 plasmid추출하여 전기영동해 본 결과 plasmid가 매우 불안정하였으며, 그중 가장 단순한 plasmid band를 지니고 있으며 amylase활성이 강한 E. coli균주를 선별하였다. 선별된 균주의 균체내에 있는 2개의 plasmid DNA를 분리하여 각각의 plasmid를 pTG 17-1, pTG 17-2로 명명하였으며 S. cerevisiae MC 16에서 형질전환이 가능한 pTG 17-2 DNA를 제한효소 EcoRI과 Pst I으로 restriction한 결과 EcoRI으로 처리한 경우는 7.3, 4.8, 2.4 kb인 3개의 분획으로 나타났으며 Pst I으로 처리한 경우는 linear로 14.5kb임을 알았으며 이로써 pTG 17-2 plasmid의 size가 약 14kb임을 알았다. 또한 E.coli균체내에서의 ampicillin sensitive로써 이 plasmid의 ampicillin resistance site가 결실되었음을 알았고 효모의 형진전환체로 부터의 $\alpha$-amylase는 균체외로 분비되지 않았고 효모균체내의 $\alpha$-amylase는 Somogyi-Nelson방법과 Agar diffusion 방법으로 확인하였다.

• Fisheries and Aquatic Sciences
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• 제17권3호
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• pp.361-367
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• 2014

Cuttlefish Sepia esculenta are commercially important in Korea. Assessments of their biomass currently depend on fishery-landings data, which may be biased. Towards fishery-independent acoustic surveys of cuttlefish, target strength (TS) measurements at 70 and 120 kHz were made of 23 live cuttlefish, in early May 2010. The fish were caught by traps in the inshore waters around Geojedo, Korea. The TS were measured using split-beam echosounders (Simrad ES60 and EY500, respectively). The cuttlefish mantle lengths (L) ranged from 15.6 to 23.5 cm (mean L=17.8 cm) and their masses (W) ranged from 335 to 1020 g (mean W=556.1 g). Their mean TS values at 70 and 120 kHz were -33.01 dB (std=1.39 dB) and -31.76 dB (std=2.15 dB), respectively. The mean TS at 70 kHz was 0.17 dB higher than the TS-length relationship resulting from a least-squares fit to the data ($TS=24.67{\log}_{10}L(cm)-64.03$, $r^2$ = 0.52, N=23). The mean TS at 120 kHz was 0.45 dB higher than the fitted TS-length relationship ($TS=40.59{\log}_{10}L(cm)-82.96$, $r^2$ = 0.58, N=23). The differences between the mean TS values and an equation regressed from all of the TS measurements at both frequencies ($TS=24.92{\log}_{10}L(cm)-4.92{\log}_{10}{\lambda}(m)-22.82$, $r^2$ = 0.86, N=46) was 0.22 dB at 70 kHz and 0.31 dB at 120 kHz, respectively.

• 한국미생물·생명공학회지
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• 제40권3호
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• pp.190-196
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• 2012

식물생장 촉진 홀몬 auxin을 생산하는 균주를 선발하기 위해 경북 경산시 소재 고추경작지 근권토양으로 부터 739종의 일반호기성 균주와 urease 생산 균주 80종 및 광합성 균주 303종과 같이 총 1000여종 이상의 균주를 분리하였다. 이 균주들을 대상으로 Salkowski test를 실시한 결과, auxin을 생산하는 158종의 일반호기성 균주와 70종의 urease 생산 균주 및 228종의 광합성 균주를 선발할 수 있었으며, Holbrook test를 통해 또 다른 식물생장 촉진 호르몬인 gibberellin도 대부분의 균주에서 생산되는 것을 확인할 수 있었다. 선발된 균주 중 항진균 물질인 ${\beta}$-Glucanase와 siderophore를 생산하고 다양한 병원성 진균에 대해 길항 범위를 가지는 6가지 균주 BCB14, BCB17, C10, HA46, HA143, HJ5를 toothpicking 및 대치배양을 통해 최종 선발할 수 있었으며, 분류학적으로 동정한 결과 6종 모두 B. subtilis BCB14, B. methylotrophicus BCB17, B. methylotrophicus C10, B. sonorensis HA46, B. subtilis HA143, B. safensis HJ5로 확인되었다.

• 대한전자공학회논문지TC
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• 제49권6호
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• pp.63-70
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• 2012

UWB 주파수대역의 안테나로써 CPW 급전의 U-자형 평면 패치 안테나모델의 지향성이득 향상 방법을 검토하였다. 지향성 이득 향상을 위해 CPW 급전의 U-자형 패치 안테나 모델에 개구슬롯 반사면을 부가하여 마이크로스트립 구조로 재구성하였다. 재구성한 안테나는 특성 임피던스 $50.08{\Omega}$에 대해 반사계수는 -6.5dB(VSWR < 3.3)이하이며 지향성이득은 7.8 dBi ~ 9.6 dBi, 전후방비는 17.8dB ~ 28.7dB 그리고 ${\theta}=0^{\circ}$의 주방사 방향에 대해 -3dB 방사각의 범위가 ${\pm}30^{\circ}$의 방사지향성의 패턴을 나타내 보였다.

• Journal of Magnetics
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• 제17권2호
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• pp.96-99
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• 2012

The change of saturation magnetization in boronized low carbon microalloyed steels was investigated as a function of boronizing time. Specimens were boronized in an electrical resistance furnace for times ranging from 3 to 9 h at 1123 K. The metallurgical and magnetic properties of the specimens were investigated using optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and vibrating sample magnetometry (VSM). A boride layer with saw-tooth morphology consisting of FeB and $Fe_2B$ was observed on the surface, its thickness ranged from 63 ${\mu}m$ to 140 ${\mu}m$ depending on the boronizing time. XRD confirmed the presence of $Fe_2B$ and FeB on the surface. The saturation magnetization decreased with increasing boronizing time. This decrease was attributed to the increased thickness of the FeB and $Fe_2B$ phases. Cracks were observed at the FeB/$Fe_2B$ interfaces of the samples. The number of interfacial cracks increased with increasing boronizing time.

• 한국초전도ㆍ저온공학회논문지
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• 제17권3호
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• pp.23-27
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• 2015

Quadruple magnet is an essential component for the accelerator, and the field uniformity in the good field region reflects the quality of quadruple magnet. In this paper, the total magnetic field B was separated into the coil-induced magnetic field $B_s$ and the iron-induced magnetic field $B_c$ to explain why the total magnetic field B has some inhomogeneity. Using Fourier analysis, harmonic components of $B_s$, $B_c$ and B have been analyzed at good field region, respectively. The harmonics of multipole magnet and Fourier analysis are helpful to show the uniformity of magnetic field. Several geometries of yoke and coils were defined to analyze the effect on field uniformity of an HTS quadruple magnet. By the analysis, it was found that the sixth harmonics which is the main factor of field inhomogeneity can be reduced to zero. It means that the sixth harmonics of the magnetic field B can be removed by adjusting the geometry of the magnet pole and the position of coils. We expect that this result can effectively improve the uniformity of an HTS quadruple magnet.

• 한국전기전자재료학회논문지
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• 제17권8호
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• pp.888-892
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• 2004

It is necessary to develop soft magnetic layer with high saturation magnetization 4 $\pi{M}_s$ and in-plane magnetic anisotropy field Hk for soft magnetic underlayer of perpendicular magnetic recording media with high signal to noise ratio. Fe-Co-B layer with high 4 $\pi$Ms of about 23 kG deposited on Ni-Fe and Ni-Fe/Si seedlayer exhibited very high in-plane magnetic anisotropy filed Hk of about 280 and 380 Oe, respectively, In-plane XRD studies clarified that the lattice spacing of planes along the easy axis direction was longer than that along the hard axis direction in the Fe-Co-B layers with high Hk. These results indicate that high Hk of Fe-Co-B/Ni-Fe and Fe-Co-B/［Ni-Fe/si］ layers were resulted from magnetoelastic anisotropy owing to a residual stress. Moreover, the high Hk in the Fe-Co-B/Ni-Fe layer was maintained until 30$0^{\circ}C$ annealing temperature.

• Asian Pacific Journal of Cancer Prevention
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• 제17권1호
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• pp.439-443
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• 2016

Background: To assess the effect of an information leaflet on the level of Chinese youth's knowledge about hepatitis B and hepatocellular carcinoma (HCC), the most common type of primary liver cancer (PLC). Materials and Methods: A total of 500 students, from two universities in the Chaoshan area of China, were randomly divided into an intervention group of 280 participants and a control group of 220. Baseline knowledge of HCC and hepatitis B was evaluated by questionnaire interview. Subsequently, only the intervention group was given an information leaflet of HCC and hepatitis B. Three months later, the two groups were contacted for a second interview. Changes in knowledge from baseline of HCC and hepatitis B were compared between the two groups. Results: There was no statistically significant difference in mean PRE-questionnaire scores between the intervention and control groups. However, the mean POST-questionnaire score was significantly higher in the intervention group after the intervention. The leaflet had the greatest effect on the participants' questionnaire score, and raised their level of knowledge about HCC and hepatitis B. Conclusions: The information leaflet intervention is significantly effective in improving the knowledge of HCC and hepatitis B among the youth.

• Asian Pacific Journal of Cancer Prevention
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• 제17권sup3호
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• pp.299-304
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• 2016

Cytolethal distending toxin (CDT) is a secreted tripartite genotoxin produced by many pathogenic gram-negative bacteria. It is composed of three subunits, CdtA, CdtB and CdtC, and CdtB-associated deoxyribonuclease (DNase) activity is essential for the CDT toxicity. In the present study, to design a novel potentially antitumor drug against lung cancer, the possible mechanisms of cdtB anticancer properties were explored in the A549 human lung adenocarcinoma cell line. A recombinant plasmid pcDNA3.1/cdtB was constructed expressing CdtB of human periodontal bacterium Aggregatibacter actinomycetemcomitans and investigated for toxic properties in A549 cells and possible mechanisms. It was observed that plasmid pcDNA3.1/cdtB caused loss of cell viability, morphologic changes and induction of apoptosis. Furthermore, measurement of caspase activity indicated involvement of an intrinsic pathway of cell apoptosis. Consequently, the recombinant plasmid pcDNA3.1/cdtB may have potential as a new class of therapeutic agent for gene therapy of lung cancer.