• Journal of Microbiology and Biotechnology
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• 제22권2호
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• pp.166-169
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• 2012

In several biotechnological applications of living bacterial cells with inducible gene expression systems, the extent of overexpression and the specificity to the inducer are key elements. In the present study, we established the concentration ranges of $Zn^{2+}$, $Ni^{2+}$, $Co^{2+}$, ${AsO_2}^-$, and $Cd^{2+}$ ions that caused significant activation of the respective promoters of Synechocystis sp. without concomitant unspecific stress responses. The low expression levels can be increased up to 10-100-fold upon treatments with $Cd^{2+}$, ${AsO_2}^-$, $Zn^{2+}$, and $Co^{2+}$ ions and up to 800-fold upon $Ni^{2+}$ treatment. These results facilitate the development of conditional gene expression systems in cyanobacteria.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.316-316
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• 2007

리튬폴리머 전지용 정극활물질인 $LiFePO_4$를 수열법으로 합성하였다. 제조한 정극활물질 $LiFePO_4$는 X-ray 회절분석을 통하여 olivine 구조임을 확인하였다. 전극 제조 시 첨가된 도전재의 종류에 따른 전기화학적 특성변화를 알기 위하여, Acetylene Black, Super-Black, Multi-Walled Carbon Nanotube(MWCNT), SP270을 도전재로 제조된 정극활물질과 PVDF를 결합제로 사용하였다. 셀은 제조된 정극과 고체전해질 $25PVDFLiCIO_4EC_{10}PC_{10}$를 사용하고, 부극은 금속리튬으로 coin 타입의 cell을 조립하여 충방전을 진행하였다. 충방전 진행결과, Multi-Walled Carbon Nanotube(MWCNT)를 도전재로 사용하였을 경우, 초기 방전용량은 94mAh/g, 100cycle 후에는 약 93mAh/g인 기타 도전재를 사용하였을 때보다 안정하고 높은 방전용량을 나타내었다. 이때의 충방전 전류밀도는 0.1mAh/g이고 전압범위 는 2.5~4.3V이었다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2008년도 춘계학술대회 논문집
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• pp.247-251
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• 2008

This paper presents a micro air pump actuated by PZT actuator (synthetic jet actuator) for air supply for micro fuel cells. The synthetic jet actuators are usually created by a traditional PZT-driven actuator, which consists of a small cylindrical cavity, in/outlet channel and PZT diaphragms. To design the micro air pump, a numerical analysis has been conducted for flow characteristics with respect to various geometries. A prototype of the micro air pump, with a size of $mm{\times}mm{\times}mm$, was fabricated by PDMS replication process and was conducted performance test. To control the PZT actuator, we used the SP4423 micro chips that can be amplified input voltage to reduce the controller size and the power consumption. With a voltage of 3V at 100Hz, the air pump's pumping pressure is 600pa and its power consumption is only 0.1mW.

• Mycobiology
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• 제32권4호
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• pp.160-163
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• 2004

Medicinal plants play important roles in controlling plant diseases as one of the safest and ecofriendly methods. These plants have been used in the form of crude extracts as well as active principles in vitro and under field conditions to control plant diseases. Among the active principles, alkaloids have shown significant antifungal activity. We have investigated the effect of two alkaloids viz., (-)-corydahnine and (-)-isocorypahnine isolated from Corydalis chaerophylla, against spore germination of some plant pathogenic and saprophytic fungal spores. Significant inhibition of spore germination at 100 ${\mu}g/ml$ was seen against Curvularia penniseti, Curvularia sp. and Colletotrichum gloeosporioides by (-)-corydahnine but (-)-isocorypalmine was also effective against fungi included in the experiment.

• Biomolecules & Therapeutics
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• 제8권3호
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• pp.262-268
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• 2000

The bioequivalence of two tiropramide products was evaluated in 18 health male volunteers following oral administration. Test product was Tira $m^{R}$ tablet (Shin Poong SP-102) (Shin Poong Pharm. Co., Ltd.) and reference product was Tirop $a^{R}$ tablet (Dae Woong Pharm. Co., Ltd.) One capsule of the test and reference product containing 100 mg of tropramide.hydrochloride was administered to the volunteers by randomized two period cross-over study (2 $\times$ 2 Latin square method). The drug concentration in plasma was determined by GC/MS for over a period of 12hours after administration. Analysis of variance reveal that there are no differences in AUC (area under the plasma concentration-time curve from time zero to infinity), Cmax (maximum plasma concentration) and Tmax (time to reach Cmax). The differences of mean AUC, Cmax and Tmax between two products were 3.85, 1.47 and -3.6%, respectively. Minimum detectable differences (%) at $\alpha$=0.1 were all less than 20% given as a guideline (18.07, 17.00 and 20.69% for AUC, Cmax and Tmax, respectively). From these results, the two products are bioequivalent.ent.

• 한국식품과학회지
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• 제4권2호
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• pp.84-89
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• 1972

An experiment was carried out to investigate the optimum doses of gamma-irradiation for sprouting inhibition of onion bulbs with irradiation time and storage conditions. The results. obtained are as follows: 1) The irradiation doses of 5, 7 and 10 krad, respectively, at 11, 32 and 66 days after harvest were sufficient to inhibit subsequent sprout of onion bulbs obtained from Nampyeong district. When they were irradiated at 96 day after harvest, however, there was little sprout-inhibition by 15 krad. In case of onion bulbs obtained from Changnyeong district, sprout was inhibited by doses of 8 and 12 krad respectively, at 51 and 89 days after harvest. 2) Low-temperature storage after irradiation was not effective in sprout-inhibition of onion bulbs. Onion bulbs stored at low temperature of $5^{\circ}C$ rather showed higher sprouting rate as compared with that of room temperature. 3) Rot increased in irradiated lot and at room temperature, and spores of Aspergillus sp. were little germinated at a level of 100 krad. 4) The respiratory rate of irradiated onion bulbs was higher immediately after irradiation but lower one week after irradiation than control. Respiratory quotient of tissues seems to be little affected by gamma-irradiation.

• Journal of Microbiology and Biotechnology
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• 제32권8호
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• pp.976-981
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• 2022

Phenanthrenes are bioactive phenolic compounds found in genus Dioscorea, in which they are distributed more in peel than in flesh. Recent studies on phenanthrenes from Dioscorea sp. peels have revealed the potential for valuable biomaterials. Herein, an analytical method using high-performance liquid chromatography (HPLC) for quantitation of bioactive phenanthrenes was developed and validated. The calibration curves were obtained using the phenanthrenes (1-3) previously isolated from Dioscorea batatas concentrations in the range of 0.625-20.00 ㎍/ml with a satisfactory coefficient of determination (R²) of 0.999. The limit of detection (LOD) and the limit of quantification (LOQ) values of the isolated phenanthrenes ranged from 0.78-0.89 and 2.38-2.71 ㎍/ml, respectively. The intraday and interday precision ranged from 0.25-7.58%. The recoveries of the isolated phenanthrenes were from 95 to 100% at concentrations of 1.25, 2.5, and 5.0 ㎍/ml. Additionally, phenanthrenes (1-3) were found in all investigated peel extracts. Hence, the developed method was encouraging for the quantitative analysis of phenanthrenes in genus Dioscorea.

• Communications for Statistical Applications and Methods
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• 제30권2호
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• pp.163-178
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• 2023

GARCH-X(1, 1) model specifies that conditional variance follows an AR(1) process and includes a past exogenous variable. This study proposes a new class from that model by allowing a more general (non-linear) variance function to follow an AR(1) process. The functions applied to the variance equation include exponential, Tukey's ladder, and Yeo-Johnson transformations. In the framework of normal and student-t distributions for return errors, the empirical analysis focuses on two stock indices data in developed countries (FTSE100 and SP500) over the daily period from January 2000 to December 2020. This study uses 10-minute realized volatility as the exogenous component. The parameters of considered models are estimated using the adaptive random walk metropolis method in the Monte Carlo Markov chain algorithm and implemented in the Matlab program. The 95% highest posterior density intervals show that the three transformations are significant for the GARCHX(1, 1) model. In general, based on the Akaike information criterion, the GARCH-X(1, 1) model that has return errors with student-t distribution and variance transformed by Tukey's ladder function provides the best data fit. In forecasting value-at-risk with the 95% confidence level, the Christoffersen's independence test suggest that non-linear models is the most suitable for modeling return data, especially model with the Tukey's ladder transformation.

• 한국환경농학회지
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• 제23권2호
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• pp.92-98
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• 2004

본 연구에서는 생물흡착제인 미역을 사용하여 인공폐액내의 중금속의 흡착 특성을 조사하였으며, 다음과 같은 결론을 얻었다. 미역 폐기물을 이용하여 제조된 생물흡착제의 단일 중금속 흡착효율은 각 중금속 100 mg/L인 용액에 biosorbent 3g을 처리했을 때 Pb는 거의 100%였고, Cu와 Cd가 약 $85{\sim}86%$, Zn과 Cr은 약 $60{\sim}64%$, Co와 Ni은 약 57%, Mn은 약 48%였다. 복합중금속 흡착효율은 단일중금속 흡착효율에 비하여 Pb를 제외한 다른 중금속들은 크게 감소되었으나 biosorbent g당 전체 중금속 흡착량은 더 증가되었다. 온도, pH에 따른 중금속 흡착효율은 별 차이가 없었으며 전반적으로 pH는 pH $5{\sim}6$ 범위, 온도는 $20{\sim}30^{\circ}C$ 범위의 실온이 적당한 것으로 나타났다. 생물흡착제의 흡착평형은 모든 중금속이 1시간 이내에 이루어졌다. Freundlich과 Langmuir 등온흡착식을 구하여 실제폐수처리에 적용여부를 검토한 결과 Pb, Cu, Cr, Cd, Co 순으로 비교적 친화도가 큰 것으로 나타났고, Freundlich 등온 흡착식에 가장 잘 일치하였다. 모든 중금속의 Freundlich 지수 1/n값이 $0.1{\sim}0.5$ 범위에 포함되어 흡착이 용이하고, Pb, Cr, Cu, Cd 순으로 비교적 평형 흡착량이 큰 것으로 나타났으며, 이 결과는 Langmuir 흡착등온식의 결과와 거의 유사하였다. 따라서, 중금속 농도범위에 따른 한계범위를 설정하여 등온흡착식을 적용시키면 매우 높은 중금속 처리효율을 나타낼 것으로 판단된다. 생물흡착제가 중금속 흡착 후의 구조적인 특성을 조사하기 위하여 FT-IR분석 결과, 중금속 이온과 치환될 것으로 생각되는 functional group을 확인할 수 있었으며, 3,400/cm에서의 -OH group, 1,648/cm에서의 C=O bond,1,426/cm에서의 C-O bond그리고 850/cm에서의 S=O등이 전반적으로 중금속 흡착 후에 peak가 커지는 것이 관찰되었다. 생물흡착제의 재사용 가능성을 검토하기 위하여 최적의 중금속 탈착조건 검토하였는데, 탈착제 종류에 따른 중금속 탈착효율은 탈착제 종류와 중금속 종류에 따라 차이가 있었고, 전반적으로 NTA>$H_2SO_4$>HCl>EDTA 순으로 우수하였으며, 전체적으로 특정 중금속의 탈착효율이 떨어지지 않는 NTA가 탈착제로 가장 적합하였다. NTA농도에 따른 중금속 탈착효율은 NTA $0.1{\sim}0.3%$ 농도범위에서는 농도 증가에 따라 탈착 효율도 약간 증가되었으나 그 이상의 농도에서는 별 차이 없었다. 온도와 pH 변화에 따른 중금속 탈착효율은 Cr을 제외한 다른 중금속들은 크게 영향을 받지 않는 것으로 나타났으며 전반적으로 온도는 $30^{\circ}C$, pH는 2에서 높았다. 탈착제 접촉 반응시간에 따른 탈착효율은 10분 이내에 전체 탈착량의 80%이상이 탈착 되었으며 1시간 이후에는 거의 변화가 없었다.

• 식물병연구
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• 제11권2호
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• pp.128-134
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• 2005

파속채소에 발생하여 큰 피해를 주는 흑색썩음균핵병균을 대상으로 외국 도입균주와 국내 분리균주간의 유전형을 UP-PCR을 이용하여 Tyson 등이 보고한 방법으로 조사한 결과, 국내에서 분리되는 Sclerotium cepivorum은 UP-PCR그룹 b에 속하는 것으로 확인되었으며, 대균핵 형성균과 DNA profile에 있어서 현저한 차이를 보였다. 두 가지 병원균의 균핵 표면구조를 전자현미경을 이용하여 확인한 결과, S. cepivorum은 대균핵 형성균에 비해 잔주름이 적고 내부에 포자와 유사한 구조가 관찰되었다. 흑색썩음균핵병을 일으키는두 가지 병원균은모두 $10\~25^{\circ}C$에 범위에서 생장되었고 생장 최적온도는 $20^{\circ}C$이었으며, $28^{\circ}C$ 이상에서는 전혀 자라지 않았다. 두 가지 병원균의 균핵 형성정도는 $20^{\circ}C$에서 배양시 가장 높았고 균핵 발아정도는 $20\~24^{\circ}C$ 범위에서 높았다 처리온도를 달리하여 처리일수별로 휴면중인 병원균 균핵의 발아정도를 조사한 결과, $35^{\circ}C$에서 7일간 전처리한 후 $10^{\circ}C$에서 7일간 배양했을 때 발아가 가장 잘 되었으며 S. cepivorum은 $70\%$,대균핵 형성균은 $100\%$발아되었다. 담수기간 및 처리온도가 병원균의 생존에 미치는 영향을 조사한 결과 처리온도가 높아질수록 균핵 발아 정도가 감소되는 것으로 나타났다. 흑색썩음균핵병을 일으키는 두 가지 병원균은 토양습도에 따라 발병정도에 있어서 큰 차이를 보였다. 마늘흑색썩음균핵병은 토양습도가 $15\%$(-300 mb)일 때 가장 높은 발병을 보였으며 $17\%$ 이상되거나 $13\%$ 이하로 되었을 때에는 토양습도가 $15\%$일 때에 비해 병 발생이 현저히 감소되었다.