• Journal of Microbiology and Biotechnology
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• 제23권7호
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• pp.1015-1022
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• 2013

We recently showed that polylysine, the polymer of lysines, retains anti-prion activity. Although the effectiveness of prion inhibition by polylysine was demonstrated with the regimen tolerated in mice, a determination of quantitative polylysine toxicity is necessary to precisely address the in vivo toxicity level of polylysine. In this communication, we report the results of body weight monitoring and hematologic tests performed in CD-1 mice that received two different tolerable dosages of polylysine for an either 5-day or 4-week period. We found that there was no significant alteration in overall serum chemistry, blood cell count, and body weight gain compared with controls. The only notable quantitative change with statistical significance was the decrease of platelet numbers in mice subchronically administered with polylysine. Our results suggest that polylysine is harmless in mice if administered for a short period, but administrations of polylysine in mice may require considerate attention for safety in future investigations as mice chronically receive tolerable doses of polylysine.

• 한국대기환경학회지
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• 제30권4호
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• pp.362-377
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• 2014

Polycyclic aromatic hydrocarbons (PAHs) have been of particular concern since they are present both in the vapor and particulate phases in ambient air. In this study, a simple method was applied to determine the vapor phase PAHs, and the performance of the new method was evaluated with a conventional method. The simple method was based on adsorption sampling and thermal desorption with GC/MS analysis, which is generally applied to the determination of volatile organic compounds (VOCs) in the air. A combination of Carbotrap (300 mg) and Carbotrap-C (100 mg) sorbents was used as the adsorbent. Target compounds included two rings PAHs such as naphthalene, acenaphthylene, and acenaphthene. Among them, naphthalene was listed as one of the main HAPs together with a number of VOCs in petroleum refining industries in the USA. For comparison purposes, a method based on adsorption sampling and solvent extraction with GC/MS analysis was adopted, which is in principle same as the NIOSH 5515 method. The performance of the adsorption sampling and thermal desorption method was evaluated with respect to repeatabilities, detection limits, linearities, and storage stabilities for target compounds. The analytical repeatabilities of standard samples are all within 20%. Lower detection limits was estimated to be less than 0.1 ppbv. In the results from comparison studies between two methods for real air samples. Although the correlation coefficients were more than 0.9, a systematic difference between the two groups was revealed by the paired t-test (${\alpha}$=0.05). Concentrations of two-rings PAHs determined by adsorption and thermal desorption method consistently higher than those by solvent extraction method. The difference was caused by not only the poor sampling efficiencies of XAD-2 for target PAHs and but also sample losses during the solvent extraction and concentration procedure. This implies that the levels of lower molecular PAHs tend to be underestimated when determined by a conventional PAH method utilizing XAD-2 (and/or PUF) sampling and solvent extraction method. The adsorption sampling and thermal desorption with GC analysis is very simple, rapid, and reliable for lower-molecular weight PAHs. In addition, the method can be used for the measurement of VOCs in the air simultaneously. Therefore, we recommend that the determination of naphthalene, the most volatile PAH, will be better when it is measured by a VOC method instead of a conventional PAH method from a viewpoint of accuracy.

• 대한화학회지
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• 제21권1호
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• pp.44-52
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• 1977

透析係數가 常數로서 나타날 수 있는 條件究明의 一環으로서 透析液 單位體積當의 透析膜面積인 比表面積과 透析膜孔의 크기가 透析에 미치는 영향을 究明하였다. 1回의 透析實驗에서 任意時間區間마다 任意부피의 透析液試料를 잇따라 菜取하는 方法(間歇試料菜取法이라 呼稱하기로 함)은 透析係數를 求하는 方法으로서 採擇할 수 있음과, 또한 透析膜孔이 상당히 크더라도 膜을 通한 擴散係數는 自由擴散係數에 미치지 못함을 밝히었다.

• 공업화학
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• 제3권4호
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• pp.588-594
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• 1992

Potassium octoate 촉매 존재하에 toluene diisocyanate(TDI)를 사용하여 polyisocyanurate를 합성할 때 용매에 포함된 수분과 부탄올이 반응물의 점도 변화율, 반응시간(생성물의 점도가 5 poise가 될 때까지의 반응시간), 생성물의 분자량 분포 및 TDI전환율에 미치는 영향을 고찰하였다. Butyl acetate용매에 포함된 수분의 양이 0.1%인 반응 조건에서 uretidione이 생성되었으며 이때 가장 높은 TDI전환율이 얻어졌다. Uretidione은 butanol을 용매에 첨가할 때는 생성되지 않았다. 첨가된 butanol양이 증가할수록 TDI전환율은 증가하고 분자량 분포도 넓어졌다.

• Food Science and Biotechnology
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• 제14권3호
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• pp.344-349
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• 2005

Aldose reductase catalyzes the conversion of glucose into sorbitol. Inhibiting this enzyme in diabetes mellitus can delay or prevent pathogenic process. Aldose reductase inhibitor was screened from Korean fermented soybean pastes (Doen-jang) and purified via sequential processes of ethanol extraction, HP-20 column chromatography, ethyl acetate extraction, silica gel column chromatography, and crystallization. Aldose reductase inhibitor was identified as genistein with molecular weight of 270 Da and molecular formula of $C_{15}H_{10}O_5$ based on UV spectrometry, $^1H$ and $^{13}C\;NMRs$, and mass spectrometry. Genistein inhibited aldose reductase of pig lens with $IC_{50}$ level of $20\;{\mu}M$. Because genistein was effective against aldose reductase of animal source, it may be a potential therapeutic agent for diabetic complications.

• Journal of Microbiology and Biotechnology
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• 제15권3호
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• pp.560-567
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• 2005

Three groups of exopolysaccharides (EPSs) (designated as Fr-I, Fr-II, and Fr-III) were isolated from the culture filtrates of Paecilomyces sinclairii by gel filtration chromatography on Sepharose CL-4B. Their molecular characteristics were examined by multi-angle laser light scattering (MALLS) connected online to a size exclusion chromatography (SEC) and refractive index (RI) detector system. The weight-average molar mass of Fr-I, Fr-II, and Fr-III of EPSs were determined to be $1.540{\times}10^6,\;6.302{\times}10^4$, and $9.389{\times}10^4\;g/mol$, respectively. All three EPSs showed a fairly low polydispersity indice, ranging from 1.008 to 1.059 (nearly mono disperse behavior), and showed different carbohydrates and amino acids compositions; all fractions of EPSs consisted of mainly cystine, valine, and arginine in the protein moiety, and mainly ribose, galactose, and glucose in the carbohydrate moiety. The determination of gyration radii of the EPSs in SEC/MALLS analysis revealed the molecular shape of the Fr-I to be a rod-like structure, whereas the Fr-II and Fr-III had a random-coil structure in an aqueous solution.

• BMB Reports
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• 제40권1호
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• pp.22-28
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• 2007

MyoD, expressed in skeletal muscle lineages of vertebrate embryo, is one of muscle-specific basic helix-loop-helix (bHLH) transcription factors, which plays a key role in the determination and differentiation of all skeletal muscle lineages. In this study, a cDNA of grass carp MyoD was cloned and characterized from total RNA of grass carp embryos by RT-PCR. The full-length cDNA of grass carp MyoD is 1597 bp. The cDNA sequence analysis reveals an open reading frame of 825 bp coding for a protein of 275 amino acids, which includes a bHLH domain composed of basic domain (1-84th amino acids) and HLH domain (98-142th amino acids), without signal peptide. Then the MyoD cDNA of grass carp was cloned to yeast expression vector pPICZ$\alpha$A and transformed into P. pastoris GS115 strain, the recombinant MyoD protein with a molecular weight of about 31KD was obtained after inducing for 2d with 0.5% methanol in pH 8.0 BMGY medium, and the maximum yield was about 250 mg/L in shaking-flask fermentation. The results were expected to benefit for further studies on the crystal structure and physiological function of fish MyoD.

• Journal of Forest and Environmental Science
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• 제23권2호
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• pp.119-122
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• 2007

Actually, about 45% of total costs for wastewater treatment in a papermaking mill is spent for sludge disposal and the cost of chemicals used to improve the dewaterability of sludge takes much part of it. In order to reduce sludge disposal cost and to improve the efficiency of sludge treatment, it is necessary to minimize the amount of water contained within the sludge and hence to improve the dewaterability of the sludge. The objective of this study was to elucidate the way of improving the dewaterability of sludge. Three types of wastewater from a tissue paper mill, a printing paper mill and a newsprint mill were used and two types of high molecular weight flocculants (anionic PAM and cationic PAM) were used to treat the wastewater. Dewaterability of sludge was evaluated by measuring floc strength.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.133-134
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• 2006

In contrast to paints, the surface appearance of adhesive materials is of minor importance, because the adhesive is invisible between the two substrates. Therefore, the rheological properties needed to apply an adhesive dispersion by spray coating can be quite different. The influence of three different kinds of thickeners on the spraying behaviour of polyurethane adhesive dispersions was investigated. The associative thickener showed only minor changes, whereas the higher molecular weight soluble thickeners dramatically changed the spraying angle and the amount of overspray. Determination of the elongational viscosity by means of the CaBER rheometer proved to be of limited use for thickened dispersions.

• 대한화학회지
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• 제17권3호
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• pp.213-223
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• 1973

透析液 및 溶媒液의 攪拌이 透膜面에 미치는 流體力學的인 壓力分布狀態를 究明하였고, 攪拌으로 招來되는 透膜面兩面의 壓力不均衡을 除去할 目的으로 攪拌裝置의 開發을 試圖하였다. 다음 攪拌速度가 透析係數에 미치는 影響을 究明하여 가장 正確한 透析係數를 求할 수 있는 攪拌速度를 確定시켰다.