• KSBB Journal
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• 제20권5호
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• pp.355-358
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• 2005

Bacteroides fragiles Roid8은 인간의 장내에서 가장 우세한 균종에 속하는 것으로서 효소활성을 측정해본 결과 다른 균들에 비해 $\alpha-fucosidase$의 활성이 높은 것으로 나타났다. 본 연구실에서 조사된 $\alpha-fucosidase$의 생산 최적배지 조성은 1L 배지당 BHI 37g, hemin 10mg, cysteine 0.5g, resazurin 1mg, vitamin K 1mg, starch 5g을 함유하였다. 또한 DEAE-sepharose와 CM-cellulose 크로마토그래피를 거쳐 조효소액을 분리하여 조사한 결과 효소의 최적 반응온도는 $40^{\circ}C$, 최적반응 pH는 7.0이었다. 무기 금속이온의 영향은 $Co^{++}\;and\;Zn^{++}$ 존재 하에서 효소역가가 낮아졌다.

• 대한의용생체공학회:의공학회지
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• 제36권6호
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• pp.283-290
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• 2015

We proposed blink based online speller for the locked-in syndrome (LIS) patients, paralyzed in nearly all voluntary muscles expect for the eyes, with a simple and easy-to-use eye blink detection glasses. Electrooculogram (EOG) is the golden standard method of eye movement or blink measurement with Ag/AgCl electrodes. However, this method has several drawbacks such as skin irritation and dehydration of conductive gel. To resolve the shortcomings, we used a blink detection system based on a transparent capacitively coupled electrode, which is conductive indium tin oxide (ITO) films. The films make it possible to measure eye blink without direct skin contact and obstruction of field of view. We finally developed user-friendly blink based online speller with the blink detection system. To classify voluntary and non-voluntary blink, we used the double blink for command of the speller. The online speller experiment result with six healthy subjects shows that mean accuracy is 98.96% and letter per minute (LPM) is 4.73, which are better result by comparison with conventional P300 or auditory brain-computer interface (BCI) paradigm. The result of the experiment demonstrates the possibility of applying the proposed system as a communication method for the LIS patients.

• Journal of Microbiology and Biotechnology
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• 제25권4호
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• pp.469-478
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• 2015

In spite of the reported probiotic effects, Bifidobacterium bifidum BGN4 (BGN4) showed no βglucosidase activity and failed to biotransform isoflavone glucosides into the more bioactive aglycones during soy milk fermentation. To develop an isoflavone-biotransforming BGN4, we constructed the recombinant B. bifidum BGN4 strain (B919G) by cloning the structural β-glucosidase gene from B. lactis AD011 (AD011) using the expression vector with the constitutively active promoter 919 from BGN4. As a result, B919G highly expressed β-glucosidase and showed higher β-glucosidase activity and heat stability than the source strain of the β-glucosidase gene, AD011. The biotransformation of daidzin and genistin compounds using the crude enzyme extract from B919G was completed within 4 h, and the bioconversion of daidzin and genistin in soy milk during fermentation with B919G also occurred within 6 h, which was much faster and higher than with AD011. The incorporation of this β-glucosidase-producing Bifidobacterium strain in soy milk could lead to the production of fermented soy milk with an elevated amount of bioavailable forms of isoflavones as well as to the indigenous probiotic effects of the Bifidobacterium strain.

• Journal of Microbiology and Biotechnology
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• 제25권4호
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• pp.464-468
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• 2015

The production of gamma-aminobutyric acid (GABA) using GABA-producing lactic acid bacteria (LAB) has been considered to be an attractive strategy. However, some LAB may produce biogenic amines (BA), which may be of concern from the safety viewpoint. The aim of the present study was to characterize the production of GABA and BA in the soybean pastes fermented by Aspergillus oryzae (A. oryzae) FMB S46471 and GABA-producing Lactobacillus brevis (L. brevis) GABA 100. After a ripening period of 90 days, the levels of BA (putrescine, cadaverine, histamine, and tyramine) and GABA in the fermented soybean were assessed by highperformance liquid chromatography. The soybean pastes fermented by A. oryzae and L. brevis showed a range of 7,130-11,592 mg/kg for GABA, 178-305 mg/kg for tyramine, 139-163 mg/kg for putrescine, 7.4-10.8 mg/kg for histamine, and 7.1-7.9 mg/kg for cadaverine, whereas the soybean pastes fermented by A. oryzae only showed a range of 30-1,671 mg/kg for GABA, 0.8-189 mg/kg for tyramine, 1.3-85 mg/kg for putrescine, up to 3.6 mg/kg for histamine, and 0.2-2.4 mg/kg for cadaverine. The results showed that the production of GABA was accompanied by the increase in the production of BA, even though the production levels of histamine and cadaverine were very low. This is the first study to simultaneously characterize the production of BA and GABA in GABA-enriched fermented soybean pastes, and warrants further study to minimize the production of BA while optimizing the production of GABA.

• Fisheries and Aquatic Sciences
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• 제7권1호
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• pp.16-22
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• 2004

Plasma steroid hormone levels in the viviparous rockfish (Sebastes schlegeli) were examined in relation to gonadal histology under controlled photoperiods and water temperatures. To investigate those effects in S. schlegeli the photoperiod was maintained at 15L:9D in June and then it was gradually decreased to 9L: 15D in October. It was then gradually increased to 12L:12D in January, followed by 14L:I0D in February. The water temperature was $19-20^{\circ}C$ in July. From August to October, it was from $18^{\circ}C\;to\;12^{\circ}C$. Then, it was dropped to a low of $19-11^{\circ}C$ in November to December and then gradually increased to $14-15^{\circ}C$ in February. In females, both plasma $estradiol-l7\beta\;$ (E2) and testosterone (T) levels from August to February showed a similar pattern in both the treatment and the control groups. In the treatment group, the peaks of plasma E2 and T were observed in November, and the peaks were closely correlated to histological observations. Oocytes contained many yolk globules (final vitellogenic oocytes), and oocytes at the migratory nucleus stage increased in size. Plasma levels of progesterone did not change much throughout the experimental period. However, in the control group, the peaks of E2, T, and progesterone were observed in February. These results indicate that the controlled photoperiod and water temperature accelerated sexual maturity, corresponding to the advancement of plasma E2 and T peaks by approximately 3 months. In males, plasma T levels showed a similar pattern from August to October in the treatment and control groups, though levels in the treatment group were higher than those in the control group. From histological observations, the treatment group copulated one month earlier.

• 한국식품과학회지
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• 제29권3호
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• pp.571-575
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• 1997

본 연구에서는 당근을 원료로 하여 Bifidobacterium을 배양하여 발효하며 Bifidobacterium의 배양특성을 살펴보았다. Bifidobacterium의 다양한 균주를 $10^6\;CFU/mL$ 수준으로 접종하여 배양하였을 때 B. longum, B. adolescentis, B. infantis 균주들은 $10^8\;CFU/mL$ 이상으로 자랐고 B. bifidum 균주들은 약간 성장이 저조하여 $10^8\;CFU/mL$ 이하 수준으로 자랐다. 당근 이외의 다른 원료로서 포도, 사과, 오렌지, 복숭아, 배추, 오이 등에 배양하였을 때 복숭아, 오렌지 등에서는 배양이 양호하였으나 포도에서는 Bifidobacterium의 성장이 일어나지 않았다. L. acidophilus와 혼합 배양시 Bifidobacterium 단독 배양시보다 균의 증식이 저하되었고 배양 24시간 후부터 Bifidobacterium의 사멸이 현저하게 일어났다. Bifidobacterium 배양에 의하여 당근의 산미가 증가되며 관능성이 개선되는 것으로 나타났다. 따라서 Bifidobacterium을 이용한 당근 발효식품 개발은 Bifidobacterium균주의 증식에 의한 기능성 증가와 당근의 관능성 개선에 도움이 될 것으로 생각된다.

• Journal of Ginseng Research
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• 제42권3호
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• pp.312-319
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• 2018

Background: Previous studies have shown that both ginseng root and ginseng berry exhibit antiobesity and antidiabetic effects. However, a direct comparison of the efficacy and mechanisms between the root and the berry after oral administration remains to be illuminated. Methods: In this study, we observed the effects of fermented ginseng root (FGR) and fermented ginseng berry (FGB) on obesity and lipid metabolism in high-fat diet induced obese mice. Results: FGR and FGB significantly inhibited the activity of pancreatic lipase in vitro. Both FGR and FGB significantly suppressed weight gain and excess food intake and improved hypercholesterolemia and fatty liver, while only FGR significantly attenuated hyperglycemia and insulin resistance. Both FGR and FGB significantly inhibited the mRNA expression of Ldlr and Acsl1 while FGR also significantly inhibited expression of Cebpa and Dgat2 in liver. FGR significantly decreased the epididymal fat weight of mice while FGB significantly inhibited the mRNA expression of genes Cebpa, Fas, Hsl, Il1b, and Il6 in adipose tissue. Conclusion: Saponin from both FGR and FGB had a beneficial effect on high-fat diet-induced obesity. Compared to FGB, FGR exhibited more potent antihyperglycemic and antiobesity effect. However, only FGB significantly inhibited mRNA expression of inflammatory markers such as interleukins $1{\beta}$ and 6 in adipose tissue.

• 한국식품과학회지
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• 제37권2호
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• pp.318-320
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• 2005

Lactobacillus reuteri는 사람과 동물의 장관 내에 존재하는 유산균의 일종으로서 혐기적 조건에서 glycerol을 대사하여 항균 물질인 루테린을 생산한다. 본 연구의 목적은 고정화된 L. reuteri를 이용하여 회분식 또는 연속식 생산 공정을 이용하여 루테린 생산의 반응 조건을 조사하는데 있었다. Agarose를 사용하여 고정화된 L. reuteri는 250mM glycerol과 반응시켜 루테린을 생산하였다. Agarose 농도를 0.5%로 조정한 회분식 생산 공정에서는 약 36시간 동안 루테린 생산이 지속되었고 시간 경과에 따라 루테린의 생산이 점차 감소하였다. 연속식 공정에서는 고정화 균이 현탁세포에 비하여 루테린 생산 시간이 약 2배 정도 연장되었으며 총 루테린의 생산 또한 502mM로 현탁 세포에 비하여 약 1.5배 증가하였다. 본 연구의 결과는 고정화 세포를 이용한 루테린 생산의 증가 가능성을 제시하였다.

• 한국유체기계학회 논문집
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• 제18권2호
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• pp.14-21
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• 2015

Design lifetime of a wind turbine is required to be at least 20 years. The most important step to ensure the deign is to evaluate the loads on the wind turbine as accurately as possible. In this study, extreme design load of a offshore wind turbine using Garrad Hassan (GH) Bladed and National Renewable Energy Laboratory (NREL) FAST codes are calculated considering structural dynamic loads. These wind turbine aeroelastic analysis codes are high efficiency for the rapid numerical analysis scheme. But, these codes are mainly based on the mathematical and semi-empirical theories such as unsteady blade element momentum (UBEM) theory, generalized dynamic wake (GDW), dynamic inflow model, dynamic stall model, and tower influence model. Thus, advanced CFD-dynamic coupling method is also applied to conduct cross verification with FAST and GH Bladed codes. If the unsteady characteristics of wind condition are strong, such as extreme design wind condition, it is possible to occur the error in analysis results. The NREL 5 MW offshore wind turbine model as a benchmark case is practically considered for the comparison of calculated designed loads. Computational analyses for typical design load conditions such as normal turbulence model (NTM), normal wind profile (NWP), extreme operation gust (EOG), and extreme direction change (EDC) have been conducted and those results are quantitatively compared with each other. It is importantly shown that there are somewhat differences as maximum amount of 18% among numerical tools depending on the design load cases.

• 한국통신학회논문지
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• 제40권2호
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• pp.285-297
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• 2015

본 논문은 compressive sampling (CS)을 활용한 Ulta-WideBand 채널 측정 및 모델링 기법을 제안한다. 기존에 실내 위치측위 기술 중 제안 UWB채널 측정 기법은 UWB 신호의 주파수 도메인에서의 sparsity 특성을 활용하여, 적은 복잡도로 합리적인 성능을 낼 수 있다. 게다가, 본 논문에서는 노이즈 환경에서 성능을 향상 시키기 위해 CS 기법에서 신호 복원기법을 위한 최적화기법으로 soft thresholding method를 제안한다. UWB시스템에서의 실내 위치추정 기법 성능 분석을 위해 실 측정 데이터를 활용하여, 제안한 채널 측정 및 모델링 기법의 성능을 위치 측정 오차, bandwidth, CS 압축률 등 다양한 조건하에 거리 오차값을 분석한다.