• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1996년도 추계학술대회
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• pp.217-220
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• 1996

In this paper, we compare three mehods to obtain PSD of HRV - FFT, AR modeling, and residual integration. Using these methods we speculate the balances of the LP and HF powers of HRV at $0^{\circ}$, $45^{\circ}$, $90^{\circ}$ tilt levels of head-up tilt table for young and healthy 24 men. R peaks are located at the highest point of QRS complex detected from modified spacial velocity algorithm. In general FFT is the most fast way to obtain PSD but PSD from FFT has too many peaks and valleies. AR PSD can show frequency of ANS activity effectively but LF component of PSD is often invisible due to interference of VLF power. The residual integration method that decomposes the AR PSD is very efficient way to extract LF component. Applying the above three methods to HRV we can visualize the trend of PSD variations along tilt levels.

• 한국토양비료학회지
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• 제33권6호
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• pp.446-452
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• 2000

전라북도 김제시 금산면 소재 옥성 동-아연 주변 농경지 토양중에 존재하는 중금속의 식물흡수도와 이동도를 예측하기 위해 연속추출법을 이용한 화학적 형태조사 및 폐광산 유출수가 주변 농업용수에 끼치는 영향을 조사한 결과는 다음과 같다. 토양중 각 중금속의 화학적 형태별 함량 분포는 Cd의 경우 organically bound > exchangeable > carbonate > residual > sulfide form, Zn 의 경우 residual > sulfide > exchangeable > organically bound > carbonate > water soluble form, Cu와 Pb의 경우 carbonate > residual > organically form > sulfide > exchangeable form, Cr은 residual > organically bound > sulfide > carbonate > exchangeable form, 그리고 Ni는 residual > exchangeable > sulfide > carbonate > organically bound form의 순서로 나타났다. 중금속의 화학적 형태별 함량 분석 결과 치환태 중금속의 함량은 각각 Cd 30.2%, Zn 11.3%, Cu 2.0%, Pb 4.6%, Cr 0.6%, Ni 3.9%로 나타나, 중금속의 이동성과 식물체의 가급성은 Cr > Cu > Ni > Pb > Zn > Cd의 순서로 나타났다. 폐광 갱내수중 중금속의 평균 함량은 Cd 0.01, Zn 27.35, Cu 4.86, Pb 1.04, Cr 0.03, Ni $0.08mg\;L^{-1}$, 폐광 유출수의 경우 Zn 16.67, Cu 0.59, Pb 049, Cr 0.05, Ni $0.06mg\;L^{-1}$, 주변 농업용수의 경우 Zn 1.26, Cu 0.05, Pb 0.05, Ni $0.02mg\;L^{-1}$로 나타났으며, Cd, Cr은 검출되지 않았다.

• 한국버섯학회지
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• 제18권4호
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• pp.387-392
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• 2020

국내 유통 중인 건조 목이 8건(국내산 3건, 중국산 5건)을 수집하여 잔류농약 321종, 중금속 7종, 방사능 3종의 유해물질 잔류성분을 조사하였다. 잔류농약 검사결과 국내산 3건에서는 검출되지 않았으나, 중국산 5건 중 4건에서 Chlorpyrifos, Isoprocarb, Mepiquat chloride, Carbendazim이 검출되었다. 농산물 농약 잔류허용기준에 의하면 목이는 Mepiquat chloride(0.5 mg/kg 이하)만 기준치가 설정되어 있다. 또한 중금속 검사결과는 모든 건조 목이에서 미량의 중금속이 검출되었으나, 기준치 이하로 낮게 나타났다. 다만 국내산 시료 1건에서 납 함량이 기준치(0.3 mg/kg)보다 높게 나타나 정확한 원인 규명을 위해서는 톱밥배지, 지하수, 보관·유통 과정에 대한 추가적인 조사가 필요할 것으로 보여진다. 방사능 조사결과에서는 모든 건조 목이에서 방사능 농도가 MDA값 이하로 불검출 수준으로 나타났다. 국내산과 중국산의 평균 방사능 농도는 요오드(131I)와 세슘(134Cs)은 비슷한 수준으로 나타났으며, 세슘(137Cs)은 국내산보다 중국산에서 다소 높게 나타났다. 방사성 세슘(137Cs)은 버섯류에 잘 농축되는 것으로 알려져 있는데 이번 조사에서는 국내 유통 중인 건조 목이는 방사능에 안전하게 나타났다.

• Asian-Australasian Journal of Animal Sciences
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• 제12권5호
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• pp.752-757
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• 1999

Studies were made of digestion of timothy (Pheleum pretense) hay, tall fescue (Festuca elatior) hay, and rice (Oryza sativa) straw in pure cultures of rumen anaerobic fungus, Neocallimastix frontails MCH3. The fungus was inoculated on ground forages (1%, w/v) in an anaerobic medium and incubated at $39^{\circ}C$. Incubation was continued for 24, 48, 72 and 96 h. The losses of dry matter, xylose and glucose of forage during incubation were determined at the end of these incubation periods. Xylose and glucose were considered to be released from xylan and cellulose, respectively. The digested xylan to digested cellulose (X/C) ratios of the substrate were calculated. Xylanase and carboxymethyl cellulose (CMCase) of culture supernatant and residual substrate was measured at the same time. The X/C ratios in the cultures on timothy hay and rice straw were greater than 0.5 in the first 24-h incubation period. The values were smaller than 0.3 in tall fesque. The ratio of xylanase activity to that of CMCase in the first 24-h incubation period correlated well with the traits in X/C ratio. However xylanase activity was still superior to CMCase in the following incubation period (48 to 96 h), although the glucose (designated as cellulose) was more intensively digested than xylose (designated as xylan). The production of these polysaccharidases appeared to correlate with substrate cell-wall sugar composition, xylose to glucose ratios, at the beginning of fast growing period.

• Journal of Applied Biological Chemistry
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• 제51권3호
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• pp.95-101
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• 2008

The gene encoding a putative esterase of Xanthomonas oryzae pv. oryzae was cloned using PCR technique. The gene was expressed with His6 tag in E. coli. One-step purification of the recombinant esterase with Ni-NTA resin resulted in one band by SDS-PAGE analysis. The purified enzyme showed a molecular weight of 30 kDa, as expected, therefore the enzyme was a mononer. The enzyme was the most active toward p-nitrophenyl (p-NP) acetate and p-NP-butyrate to a lesser extent. However, the enzyme could not hydrolyze p-NP-myristate, palmitate, and stearate. Therefore, the enzyme is considered as an esterase, very different from lipase. The purified esterase had optimal pH at around 8.0 and was stable in a broad range of pH values. The optimal temperature ranged from 30 to $40^{\circ}C$, and the residual activity observed after heat treatment at $55^{\circ}C$ for 20 min was 72 % of the initial activity. The activity was inhibited by the presence of copper and cobalt ions.

• Journal of Microbiology and Biotechnology
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• 제26권10호
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• pp.1717-1722
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• 2016

A novel phytase of Acidobacteria was identified from a soil metagenome, cloned, overexpressed, and purified. It has low sequence similarity (<44%) to all the known phytases. At the optimum pH (2.5), the phytase shows an activity level of 1,792 μmol/min/mg at physiological temperature (37℃) and could retain 92% residual activity after 30 min, indicating the phytase is acidophilic and acidostable. However the phytase shows poor stability at high temperatures. To improve its thermal resistance, the enzyme was redesigned using Disulfide by Design 2.0, introducing four additional disulfide bridges. The half-life time of the engineered phytase at 60℃ and 80℃, respectively, is 3.0× and 2.8× longer than the wild-type, and its activity and acidostability are not significantly affected.

• Journal of Microbiology and Biotechnology
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• 제24권10호
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• pp.1382-1388
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• 2014

Proteus vulgaris K80 lipase was expressed in Escherichia coli BL21 (DE3) cells and immobilized on amine-terminated magnetic microparticles (Mag-MPs). The immobilization yield and activity retention were 84.15% and 7.87%, respectively. A homology model of lipase K80 was constructed using P. mirabilis lipase as the template. Many lysine residues were located on the protein surface, remote from active sites. The biochemical characteristics of immobilized lipase K80 were compared with the soluble free form of lipase K80. The optimum temperature of K80-Mag-MPs was $60^{\circ}C$, which was $20^{\circ}C$ higher than that of the soluble form. K80-Mag-MPs also tended to be more stable than the soluble form at elevated temperatures and a broad range of pH. K80-Mag-MP maintained its stable form at up to $40^{\circ}C$ and in a pH range of 5.0-10.0, whereas soluble K80 maintained its activity up to $35^{\circ}C$ and pH 6.0-10.0. K80-Mag-MPs had broader substrate specificity compared with that of soluble K80. K80-Mag-MPs showed about 80% residual relative activity after five recovery trials. These results indicate the potential benefit of K80-Mag-MPs as a biocatalyst in various industries.

• 한국미생물·생명공학회지
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• 제48권3호
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• pp.358-365
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• 2020

An organic solvent- and bleach-stable protease-producing strain was isolated from a polluted river water sample and identified as Aeromonas veronii OB3 on the basis of biochemical properties (API 20E) and 16S rRNA sequence analysis. The strain was found to hyper-produce alkaline protease when cultivated on fish waste powder-based medium (HVSP, 4080 U/ml). The biochemical properties and compatibility of OB3 with several detergents and additives were studied. Maximum activity was observed at pH 9.0 and 60℃. The crude protease displayed outstanding stability to the investigated surfactants and oxidants, such as Tween 80, Triton X-100, and H₂O₂, and almost 36% residual activity when incubated with 1% SDS. Remarkably, the enzyme demonstrated considerable compatibility with commercial detergents, retaining more than 100% of its activity with Ariel and Tide (1 h, 40℃). Moreover, washing performance of Tide significantly improved by the supplementation of small amounts of OB3 crude protease. These properties suggest the potential use of this alkaline protease as a bio-additive in the detergent industry and other biotechnological processes such as peptide synthesis.

• 한국미생물·생명공학회지
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• 제19권3호
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• pp.209-214
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• 1991

Lactococcus sp. 1112-1 균주가 생산하는 bacteriocin을 정제하고 특성을 조사하였다. CM-sephadex ion exchange column chromatography, Sephadex G-50 gel filtration, SDS-PAGE를 행함으로서 수율 16.2 정제도 123배의 단일물질을 얻었다. 이 물질은 열에 비교적 안정하여 $60^{\circ}C$에서 60분간 열처리 할 때 38의 잔존활성을 유지하였으며 알카리쪽에서는 비교적 불안정하여 pH 8.0에서 48시간 처리시 77의 활성을 소실하였다. 이 물질은 26개의 아미노산 잔기를 이루고 있었다.

• Journal of Ginseng Research
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• 제1권1호
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• pp.25-28
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• 1976

몇 가지 유기용매를 사용하여 인삼 추출액을 분별 분리하여 몇 개의 분칠들을 얻어서 이들이 RNA중합효소의 활동성에 미치는 영향을 조사하였다. 백삼과 홍삼에서 모두 RNA 중합효소의 활동성에 양성적인 효과를 가진 분획들을 얻었다. 백삼의 경우 RNA 중합효소에 양성적인 효과를 미치는 성분들은 전체 메탄을 추출액 분획, 초산에틸 추 출모액 및 이 모액의 수용성 분획들에서 확인되었고 흥삼의 경우에는 전체 메탄을 추출액 분획과 에테르 분획들에서 확인되었다. 이 사실은 중합효소에 양성적인 효과를 나타내는 성분들이 무극성 및 극성 부분들로 이루어져 있으며, 그들이 홍삼의 가공과 정에서 두 부분으로 분해되었을 것이라는 것을 암시의 준다.