• Journal of the Korean Society of Food Science and Nutrition
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• v.25 no.1
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• pp.143-149
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• 1996

균주개량 방법의 일환으로 electrofusion 법을 이용하여 protease 화성, lipase 활성, 내열성, 내산성 등이 우수한 L. bulgaricus와 bacteriocin을 생산하는 L. acidophilus 간의 융합조건을 검토하였다. Electrofusion에 의해 생성된 융합주는 식별하기 위해 streptomycin(2mg/ml)과 lincomycin(5$\mu\textrm{g}$/ml)에 내성을 나타내는 L. bulgaricus 변이주이와 kanamucin (600$\mu\textrm{g}$/ml)에 내성을 나타내는 L. acidophilus 88 변이주를 분리하였다. Electrofusion을 500V/cm, 100mses(49phms, 2300 capacotance)에서 수행했을 때 가장 융합이 잘 일어났으며 전기장의 세시와 시간이 증가할수록 융합요율이 현저히 감소하였다. 2가 양이온은 대체적으로 융합효율을 감속시키는 경향을 나타내었으나 1mM MgCl$_2$에서 융합 효율이 약간 증가하였다. PEG 400을 elec-trogusion buffer에 30%되도록 첨가했을 때, 가장 양호한 융합효율을 나타내었으며 그 이상에서는 오히려 융합 효율이 감소하였다. Electrofusion법과 PEG 매개에 의한 융합법의 융합 효율을 비교한 결과, 거의 비슷한 융합 효율을 나타내었으나 electrofusion 법과 PEG매개에 의한 융합법을 혼합하였을 때 가장 양호한 융합 효율을 나타내었다.

• Microbiology and Biotechnology Letters
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• v.9 no.3
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• pp.109-116
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• 1981

Three edible species and one species utilized as drug were selected from wild mushrooms collected from mountains and fields throughout Korea during 1977 to 1979 for artificial cultivation. The media, MES for G. lucidum, MHS for P. rudis and MSES and MHS for P. adipose and Pluteus sp. were selected. The range of optimum pH was 4.0 to 5.0 in citric acid-sodium phosphate dibasic for the tested species. The range of optimum temperature for the mycelial growth of G. lucidum and P. adiposa was 25 to 3$0^{\circ}C$ and 30 to 35$^{\circ}C$ for P. rudis and Pluteus sp. For the moisture content 75 to 80% (w/w) in the substrates, the mycelial growth of most tested species was rapid. As the spawning substrates, poplar sawdust for G. lucidum and Pluteus sp., oak sawdust for P. rudis and wheat for P. adipose were selected, respectively. In this experiment, the fruit bodies of all tested species were appeared. Among them, G. lucidum for medicinal purpose and P. adiposa and Pluteus sp. for sources of new edible mushrooms seems to be possible. However, the sporophores of P. rudis were not adequate as an edible mushroom for the commercial due to the leathery flesh.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.5
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• pp.727-739
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• 2021

Over the past decades, the Jordanian government has made great efforts to help poor women start small businesses by providing microcredit and facilitating financial services. Although in Jordan almost hundreds of thousands of women have the ability to contribute more fully to their economy, they are reluctant to do so. Women's participation in economic activities in 2016 was only 13.2%, while the unemployment rate for Jordanian women was 24.1%. The decline in women's participation in small business management has gradually become an important issue following the trial of more than 13,000 Jordanian women for non-payment of their micro-loans. This study aims to identify the factors that hinder Jordanian women from achieving job stability. In this qualitative study, a semi-structured interview method with sixteen open-ended questions was used to collect relevant data. A purposeful sampling method is also used to select participants. To analyze the data, this study used NVivo 11 software as a method. Using System Theory, this study showed that women's failure depends on three factors: women entrepreneurs, the environment around women entrepreneurs, and micro-financial institutions. Findings of this study suggest that strengthen women's entrepreneurship sustainability and minimize the risk of failure should be done through integrated strategies include these three domains.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.6
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• pp.333-342
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• 2014

The pilot assisted channel frequency response (CFR) estimation schemes for an OFDM-based system with virtual subcarriers are analyzed under the assumption that pilot symbols are located according to a comb-type pattern in the OFDM block. In particular, as the minimum mean square error (MMSE) based scheme aiming to directly predict the channel impulse response and the MMSE based scheme aiming to suppress the leakage have not been clearly compared, by proving that the mean square errors (MSEs) of the latter scheme is always larger than that of the former scheme, this paper shows that the former scheme is superior to the latter scheme. Moreover, the impact of the number of pilots on the performances of the MMSE and least-square based channel estimation schemes are investigated. The performance analyses of the presented schemes are confirmed by computer simulation.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.3
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• pp.202-211
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• 2017

In this study, numerical simulations were performed using the ${\gamma}-Re_{\theta}$ transition model of KFLOW for the transitional flow over the KARI-11-180 airfoil. Numerical results of KFLOW were compared with experimental data and two other numerical results of XFoil and MSES. Fully turbulence model was predicted high skin friction drag than transition model because fully turbulence model could not solve the transitional flow. Numerical predictions using the ${\gamma}-Re_{\theta}$ model of KFLOW show a good agreement with experimental data and other numerical results. Present numerical results were confirmed the state of drag bucket due to dramatic changing of the transition location on the airfoil surface.

• Food Science and Preservation
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• v.22 no.5
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• pp.751-757
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• 2015

The objective of this study was to investigate the protective effects of mulberry (Morus alba) sugar extracts (MSE) against $H_2O_2$-induced oxidative stress in HepG2 cells. The MSEs was mixed with matured mulberry and sugar at the same ratio (1:1, w/w) and stored at $18{\pm}3^{\circ}C$ for 40 days. In 2,2-diphenyl-1-picryl-hydrazyl (DPPH) radical scavenging test, MSE stored for 40 days showed high activity with a ratio above 66%. Therefore, we selected 40 days as the optimum storage period. After cell viability analysis using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, we determined that the optimum concentration of MSE was 0.5%. Our results showed that MSE increased the cell viability and antioxidant enzyme activities of superoxide dismutase (SOD) and catalase in $H_2O_2$-treated HepG2 cells. Moreover, the treatment with MSE inhibited malondialdehyde (MDA) levels in $H_2O_2$-treated HepG2 cells. We also observed a reduction in apoptotic bodies in the Hoechst staining. These data show that MSE treatment significantly suppressed caspase-3 activity in HepG2 cells expored to $H_2O_2$-induced oxidative stress, thereby indicationg the protective effects of MSE in $H_2O_2$-induced oxidative stress.

• Wind and Structures
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• v.28 no.2
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• pp.71-87
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• 2019

The yaw and interference effects of blades affect aerodynamic performance of large wind turbine system significantly, thus influencing wind-induced response and stability performance of the tower-blade system. In this study, the 5MW wind turbine which was developed by Nanjing University of Aeronautics and Astronautics (NUAA) was chosen as the research object. Large eddy simulation on flow field and aerodynamics of its wind turbine system with different yaw angles($0^{\circ}$, $5^{\circ}$, $10^{\circ}$, $20^{\circ}$, $30^{\circ}$ and $45^{\circ}$) under the most unfavorable blade position was carried out. Results were compared with codes and measurement results at home and abroad, which verified validity of large eddy simulation. On this basis, effects of yaw angle on average wind pressure, fluctuating wind pressure, lift coefficient, resistance coefficient,streaming and wake characteristics on different interference zone of tower of wind turbine were analyzed. Next, the blade-cabin-tower-foundation integrated coupling model of the large wind turbine was constructed based on finite element method. Dynamic characteristics, wind-induced response and stability performance of the wind turbine structural system under different yaw angle were analyzed systematically. Research results demonstrate that with the increase of yaw angle, the maximum negative pressure and extreme negative pressure of the significant interference zone of the tower present a V-shaped variation trend, whereas the layer resistance coefficient increases gradually. By contrast, the maximum negative pressure, extreme negative pressure and layer resistance coefficient of the non-interference zone remain basically same. Effects of streaming and wake weaken gradually. When the yaw angle increases to $45^{\circ}$, aerodynamic force of the tower is close with that when there's no blade yaw and interference. As the height of significant interference zone increases, layer resistance coefficient decreases firstly and then increases under different yaw angles. Maximum means and mean square error (MSE) of radial displacement under different yaw angles all occur at circumferential $0^{\circ}$ and $180^{\circ}$ of the tower. The maximum bending moment at tower bottom is at circumferential $20^{\circ}$. When the yaw angle is $0^{\circ}$, the maximum downwind displacement responses of different blades are higher than 2.7 m. With the increase of yaw angle, MSEs of radial displacement at tower top, downwind displacement of blades, internal force at blade roots all decrease gradually, while the critical wind speed decreases firstly and then increases and finally decreases. The comprehensive analysis shows that the worst aerodynamic performance and wind-induced response of the wind turbine system are achieved when the yaw angle is $0^{\circ}$, whereas the worst stability performance and ultimate bearing capacity are achieved when the yaw angle is $45^{\circ}$.