• Journal of Applied Biological Chemistry
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• v.60 no.2
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• pp.113-117
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• 2017

Bioremediation is a technique using microorganisms to clean up contaminated pollutants including heavy metals. It is well known that yeasts have a high capacity to remove a wide range of metals by biosorption. Therefore, this study was focused on to obtain yeast mutant that has strong tolerance to zinc (Zn), one of representative heavy metals. The Zn resistant yeast mutant (ZnR) was induced and isolated by growing yeast cells in media containing 1 mM $ZnCl_2$ and gradually increasing the concentration until 80 mM $ZnCl_2$, in which cells were adapted and survived. The induced ZnR cells showed strong tolerance to Zn stress compared with control cells. Moreover, the ZnR cells showed increased tolerance to cadmium and nickel stress but decreased tolerance to copper stress. The increased tolerance of ZnR cells to Zn stress was due to mutation of genes. This study can be useful in bioremediation of heavy metals as the metal tolerant microorganism was artificially induced in short time.

• Journal of Applied Biological Chemistry
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• v.54 no.2
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• pp.108-113
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• 2011

The tyrosinase inhibitory activity of extracts from Phellodendron amurense was examined. Tyrosinase inhibitory activity of 60% ethanol extracts was determined as 25% and the inhibitory activity of 60% ethanol extracts against melanin biosynthesis in melanoma cell (B16F10) was 31.2%. The purified inhibitory compounds against tyrosinase by Sephadex LH-20, MCI-gel CHP-20 column chromatography from P. amurense was confirmed as obacunone by $^1H$-NMR, $^{13}C$-NMR and Fast atom bombardment (FAB)-Mass spectrum. The tyrosinase inhibitory activities of purified obacunone was respectively as 35.1%. The safety of essence with tyrosinase inhibitory compounds from P. amurense was also assayed by various safety profiles. First, pH and viscosity change of essence for 60 days were not detected. The essence also showed the stability against temperature and light for 60 days. All these findings suggest that extracts from P. amurense has a great potential as a cosmeceutical ingredient, which has a potent whitening effect.

• Food Industry
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• s.99
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• pp.32-37
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• 1989

양질의 국산 생강엑기스 제조기술 개발을 위한 본 연구결과를 요약하면 다음과 같다. 1) 본 연구에서 시료로 사용한 생강은 전라북도 봉동산과 충청남도 서산산이며, 이들 건강은 수분이 약$10\%$, 회분 $8\~9\%$, 조지방 $4\~5\%$이다. 2) 생강엑기스의 유효성분들은 건강입자에 내포되어 있는 상태에서 추출 속도는 반응층을 통한 확산모델로 설명된다. 침출 효율을 개선하기위해서는 다음과 같은 조건이 필수적이다. 3) 건강의 입자는 $10\~20{\mu}m$정도의 전분입자가 될수록 많이 노출되도록 160목을 통과하는 작은 입자로 분쇄하면 추출효율은 최대화 할 수 있다. - 추출온도는 엑기스의 주요성분의 손실이 무시되는 최대온도, $40^{\circ}C$가 최적이다. - 160목, $40^{\circ}C$에서 추출시간 3-4시간이 최적이다. - 이같은 조건에서의 엑기스 회수율은 약 $8\%$이다. 4) 엑기스내의 비자극성 성분은 회분 $0.5\~0.8\%$, 조지방 $1.2\~1.8\%$, 조단백 $2.8\~3.5\%$이고, 유리당은 거의 침출되지 않는다. 엑기스내의 주요 지방산은 Linoleic acid가 가장 많이 함유되어 있다. 5) 기계건조보다 일광건조에 의한 건강에서 추출된 엑기스의 품질이 양호하며, 외국산 고급 엑기스와 품질면에서 대등한 것이다. 6) 위와 같은 결과는 TLC로 분리하고 분리된 각 Spot를 HPLS로 분석, IR, NMR, LC/MS를 사용하여 주요성분을 확인 및 정량화하였다. 이로부터 엑기스내의 주요성분은 gingerol이 약 0.38, Shogaol이 약 0.027, 그리고 Paradol이 0.03의 농도분율을 가지고 있음을 알았다. 7) 기계건조 건강으로부터 얻은 엑기스는 상온 $\~100^{\circ}C$ 범위에서 휘발 및 열분해에 의한 무게감량이 양건강에 비해 약 2.7배나 높다. 그러므로 생강엑기스를 사용하여 제조되는 생강차 제조시 열풍건조($60^{\circ}C$, 30분)는 품질에 지대한 영향을 미친다는 것을 발견하였다. 8) 생강엑기스 제조는 건강 재배방법 저장기간과 방법, 건조방법이 건강특성을 좌우한다. 9) 본 연구에서 제시된 열분석(DSC와 TGA)방법을 도입한다면 신속하고 경제적으로 생강 엑기스 품질을 평가하는 데에 큰 기여가 있을 것으로 생각된다. 10) 양호한 생강차를 만들 수 있다고 선정된 엑기스는 수입 엑기스와 함께 양건강의 제품이다.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.7 no.2
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• pp.9-17
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• 2012

This paper integrates elements from the theory of agency, the entrepreneurship education, the start-up policies. Entrepreneurship education is demanded to enhance success of business candidate for business establishment and to increase start-up survival. Three researches are made by this study. First of all, Educational performance is measured and it explains why linked policies is needed. To explain linked performance, this paper introduces several hypothesis. These are about a rate of start-up failure caused by agency problem and a rate of education effect decreasing agency problem. Secondly, operation performance of it can be increased by linking among policies and should be for the original goals of start-up policies. Finally, several ideas including start-up certification is proposed. Start-up certification has role of contact point of different entrepreneurship policies. As a result, level of satisfaction of policies will increase and specially of education program by linked effects.

• Applied Chemistry for Engineering
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• v.10 no.4
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• pp.515-522
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• 1999

Asymmetric polyetherimide membrane were prepared by phase inversion method, and the effects of NaOH concentration and reaction time on the morphology change of the polyetherimide membranes were studied. The morphology of skin layers varied from dense structure to sphere structure with increasing concentration of modification solution. The thickness of dense layer increased with increasing reaction time. However, when either the concentration of modifying solution was very high or the reaction time was very long, the dense layers of the asymmetric membrane were disappeared. From these results, it was found that the surface morphology of the asymmetric polyetherimide membranes depended strongly on the modification conditions such as concentration of modification solution and reaction time. These results might be explained by the hydrolysis reaction of polyetherimide into polyamic acid by the NaOH solution.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.1
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• pp.32-36
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• 1997

As a fundamental research for the development of pumpkin products, the changes of carotenoids were investigated in hot air dried pumpkin powder packed in PE/nylon film during storage at 2$0^{\circ}C$ under the dark and bright conditions. Total amounts of carotenoids in the dehydrated pumpkin powder were reduced by 65~70 percentage without effect of light after one month. The carotenoids of pumpkin powder were separated to five spots without effect of light by TLC, but difference of color was not significant throughout the storage period. By the analysis of HPLC, leutin, under bright condition, was increased from 15 days of storage but under dark condition it was not changed for one month. Meanwhile, p-carotene, under bright condition, was decreased from 15 days of storage but under drak condition it was decreased from 25 days. The contents of lycopene and $\alpha$ -carotene did not show any significant change throughout the storage period. In color analysis, yellowness value was de- creased in bright as well as dark condition from 10 day storage.

• The Journal of the Acoustical Society of Korea
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• v.19 no.3
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• pp.26-34
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• 2000

In this paper, we propose a 4kbps speech coder that combines the harmonic vector excitation coding with time-separated transition coding. The harmonic vector excitation coding uses the harmonic excitation coding in the voiced frame and uses the vector excitation coding with the structure of analysis-by-synthesis in the unvoiced frame, respectively. But two mode coding method is not effective for transition frame mixed in voiced and unvoiced signal and a new method beyond using unvoiced/voiced mode coding is needed. Thus, we designed a time-separated transition coding method for transition frame in which a voiced/unvoiced decision algorithm separates unvoiced and voiced duration in a frame, and harmonic-harmonic excitation coding and vector-harmonic excitation coding method is selectively used depending on the previous frame U/V decision. In the decoder, the voiced excitation signals are generated efficiently through the inverse FFT of harmonic magnitudes and the unvoiced excitation signals are made by the inverse vector quantization. The reconstructed speech signal are synthesized by the Overlap/Add method.

• Journal of Labour Economics
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• v.38 no.4
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• pp.83-107
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• 2015

Free Agent(FA) system allows a professional player to make a salary contract with the other clubs as well as the incumbent one after the player has played in one club for a fixed periods. Sometimes compared with the salary FA players performs very poorly, which leads to a debate about FA busts. We extend the model of Yang and Wang(2013) to the one with incomplete information about the productivity of the player to explain the possibility of FA busts. FA busts do not arise in the separating equilibrium where the private information is fully revealed. The FA busts do occur in the pooling equilibrium We show that the separating equilibrium does not exist. We also show that under some conditions, in particular with strong compensation rule, the unique pooling equilibrium exists.

• Korean Journal of Food Science and Technology
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• v.35 no.6
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• pp.1150-1154
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• 2003

The characteristics of a strain that contaminates the manufacturing of rice vinegar by Acetobacter pasteruianus was invetigated. Conditions for inhibiting pellicle formation and growth of the contaminant, which occurs during static culture and storage, were also observed. Examining the morphological, cultural, and physiological characteristics and measuring the amount of cellulose production during static culture for 14 day, we found that the strain was known to be Acetobacter xylinum. No growth was observed below $10^{\circ}C$ as well as over $40^{\circ}C$. Also, the extent of growth was limited when the concentrations of ethanol, NaCl, and acetic acid were more than 10%, 1.5%, and 7%, respectively.

• Microbiology and Biotechnology Letters
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• v.31 no.1
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• pp.46-50
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• 2003

Lactococcus lactis SA72 from Jeot-gal (Korean traditional fermented fish foods) produces lacticin SA72. The influence of several parameters on the fermentative production of lacticin SA72 by Lactococcus lactis SA72 was studied. MRS medium among several media was selected for enhanced bacteriocin production. The mean growth rate and bacteriocin productivity of L. lactis SA72 increased as the initial pH of the media increases. The highest lacticin SA72 activity was detected 3,200 AU/ml at pH 6.0, $32^{\circ}C$, and 1% (inoculum size, v/v) in the jar fermenter. Enhanced production of lacticin SA72 was investigated by a fed-batch cultivation with the intermittent feeding of the concentrated glucose solution. Under the optimized conditions, lacticin SA72 activity finally reached to 6,400 AU/ml.