• Macromolecular Research
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• 제13권1호
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• pp.45-53
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• 2005

In this study, a series of highly swelling hydrogels based on sodium alginate (NaAlg) and polymethacryl­amide (PMAM) was prepared through free radical polymerization. The graft copolymerization reaction was performed in a homogeneous medium and in the presence of ammonium persulfate (APS) as an initiator and N,N'-methylenebis­acrylamide (MBA) as a crosslinker. The crosslinked graft copolymer, alginate-graft-polymethacrylamide (Alg-g­PMAM), was then partially hydrolyzed by NaOH solution to yield a hydrogel, hydrolyzed alginate-graft-poly­methacrylamide (H-Alg-g-PMAM). During alkaline hydrolysis, the carboxamide groups of Alg-g-PMAM were converted into hydrophilic carboxylate anions. Either the Alg-g-PMAM or the H-Alg-g-PMAM was characterized by FTIR spectroscopy. The effects of the grafting variables (i.e., concentration of MBA, MAM, and APS) and the alkaline hydrolysis conditions (i.e., NaOH concentration, hydrolysis time, and temperature) were optimized systematically to achieve a hydrogel having the maximum swelling capacity. Measurements of the absorbency in various aqueous salt solutions indicated that the swelling capacity decreased upon increasing the ionic strength of the swelling medium. This behavior could be attributed to a charge screening effect for monovalent cations, as well as ionic cross-linking for multivalent cations. Because of the high swelling capacity in salt solutions, however, the hydrogels might be considered as anti-salt superabsorbents. The swelling behavior of the superabsorbing hydrogels was also measured in solutions having values of pH ranging from 1 to 13. Furthermore, the pH reversibility and on/off switching behavior, measured at pH 2.0 and 8.0, suggested that the synthesized hydrogels were excellent candidates for the controlled delivery of bioactive agents. Finally, we performed preliminary investigations of the swelling kinetics of the synthesized hydrogels at various particle sizes.

• Food Science and Biotechnology
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• 제17권4호
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• pp.766-771
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• 2008

The proteolytic enzyme from Saccharomyces sp. B101 was purified to homogeneity by ammonium sulfate fractionation, ultrafiltration, diethyl aminoethyl (DEAE)-Sephadex A-50 ion-exchange chromatography, and Sephadex G-100 gel filtration chromatography from the culture supernatant of Saccharomyces sp. B101. The specific activity and the purification fold of the purified enzyme were 4,688.9 unit/mg and 18, respectively. The molecular weight of the purified enzyme was estimated to be 33 kDa by sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The optimum pH and temperature for the enzyme activity were pH 8.5 and $30^{\circ}C$, respectively. The enzyme activity was relatively stable in the pH range of 6.5-8.5 at below $35^{\circ}C$. The salt-tolerance and stability for the enzyme activity were relatively stable even at NaCl concentrations of 10 and 15%. The activity of enzyme was inhibited by $Ag^{2+}$ and $Fe^{2+}$, and activated by $Mn^{2+}$. In addition, the enzyme activity was potently inhibited by ethylenediaminetetraacetic acid (EDTA) and phenylmethyl sulfonylfluoride (PMSF). Based on these findings we concluded that the purified enzyme was a serine protease. Km and Vmax values for hammastein milk casein were 1.02 mg/mL and 278.38 unit/mL, respectively.

• 농업과학연구
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• 제3권1호
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• pp.105-119
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• 1976

Caramel 색소(色素)의 원료(原料) 대체(代替)를 위(爲)한 기초연구(基礎硏究)로서 자당(蔗糖), 포도당(葡萄糖), 전분당화액(澱粉糖化液) 및 전분질원료당화액(澱粉質原料糖化液)을 여러 가지 촉매하(觸媒下)에서 Caramel화(化) 시킨 다음 그 제품(製品)을 분석(分析)한 결과(結果)는 다음과 같다. 1. Sucrose syrup에 pH3.5가 되도록 산(酸)($H_2SO_4$)을 가(加)한 다음 Caramel화(化)하면 색력(色力)이 비교적(比較的) 강(强)하고 색조양호(色調良好)하며 내식염성(耐食鹽性), 내(耐)Tannin성(性) 및 내(耐)Alcohol성(性)이 강(强)한 품제(品製)이 되었다. 2. Sucrose syrup에 pH9.5가 되도록 Alkali($Na_2CO_3$)를 가(加)하여 Caramel화(化)한 제품(製品)은 색력(色力)이 매우 강(强)하나 적미(赤味)가 약간(若干) 떨어지며, 내(耐)Alcohol성(性)이 강(强)하였으나 내염성(耐鹽性) 및 내(耐)Tannin성(性)이 약(弱)하였다. 3. Sucrose syrup에 $NH_4Cl$ 및 $(NH_4)_2SO_4$와 같은 Ammonium의 강산염(强酸鹽)을 가(加)하여 Caramel화(化)하면 색력(色力)은 매우 강(强)하나 적미(赤味)가 부족(不足)하고 안정성(安定性)이 대단(大端)히 약(弱)한 제품(製品)이 되었으며 $(NH_4)_2CO_3$ 및 $(NH_4)_2SO_3$와 같은 Ammonium의 약산염(弱酸鹽)을 가(加)하였을때에는 색력(色力)이 비교적(比較的) 강(强)하고 색조양호(色調良好) 하며 내염성(耐鹽性) 및 내(耐)Alcohol이 강(强)하였으나 내(耐)Tannin성(性)은 약(弱)하였다. 4. Glucose syrup에 pH9.5에 달(達)하도록 Alkali($Na_2CO_3$)를 가(加)하여 Caramel화(化)하면 색력(色力)을 매우 강(强)하나 적미(赤味)는 떨어지고 내염성(耐鹽性) 및 내(耐)Alcohol은 강(强)하였으나 내(耐)Tannin성(性)은 약(弱)한 제품(製品)이 되었다. 5. Glucose syrup에 각종(各種) Ammonium염(鹽)을 첨가(添加)하고 Caramel화(化) 시켰을 때 $NH_4Cl$구(區)는 색력(色力)이 극(極)히 약(弱)하고 색조불량(色調不良)하며 내(耐)Tannin성(性)도 약(弱)한 제품(製品)이 되었으나 $(NH_4)_2CO_3$, $(NH_4)_2SO_4$, 및 $(NH_4)_2SO_3$ 구(區)는 모두 색력(色力)이 매우 강(强)하였으나 적미(赤味)는 떨어지고 내(耐)Tannin성(性)도 약(弱)하였으나 $(NH_4)_2SO_3$구(區)는 내염성(耐鹽性) 및 내(耐)Alcohol성(性), $(NH_4)_2SO_3$구(區)는 내(耐)Alcohol성(性), $(NH_4)_2SO_4$구(區)는 내염성(耐鹽性)이 강(强)하였다. 6. 각종전분(各種澱粉)의 산당화액(酸糖化液)을 산성하(酸性下)에서 $(NH_4)_2SO_4$를 첨가(添加)하여 Caramel화(化) 하였을 때 감자 전분당화액구(澱粉糖化液區)가 색력(色力)이 가장 강(强)하여 Glucose Caramel의 그것과 비숫한값(2.385)을 나타내었으며 다음이 고구마 전분당화액구(澱粉糖化液區)(1.665)이고 옥수수 전분당화액구(澱粉糖化液區)의 색력(色力)(0.90)이 가장 약(弱)하였으며 이들은 모두 내염성(耐鹽性)이 강(强)하고 내(耐)Tannin성(性) 및 내(耐)Alcohol성(性)이 약(弱)하였다. 7. 건조(乾燥) 분쇄(粉碎)한 고구마, 도토리, 및 굴발분말(粉末), 물로 7일간(日間) 추출(抽出), 경사(傾斜)시키거나 50% Alcohol 용액(溶液)에 24시간(時間) 추출과정(抽出過)한 도토리 및 굴밤분말(粉末)을 전분당화시(澱粉糖化時) 동일방법(同一方法)으로 산당화(酸糖化)시킨 다음 Caramel화(化)하여 그 제품(製品)을 분석(分析)한 결과(結果), 거의 대부분(大部分) 색력(色力)이 약(弱)하고 적미부족(赤味不足)하며 안정성(安定性)도 매우 떨어져, 전분(澱粉)의 분리(分離), 정제(精製), 또는 당액(糖液)의 정제(精製)가 선행(先行)되어야 할것으로 생각되었다.

• 한국결정성장학회:학술대회논문집
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• 한국결정성장학회 1997년도 Proceedings of the 12th KACG Technical Meeting and the 4th Korea-Japan EMGS (Electronic Materials Growth Symposium)
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• pp.3-5
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• 1997

Synthesis of ammonium aluminum hydrogen carbonate(AAHC) via reaction of aluminum bicarbonate and aluminum salt and thermal decomposition is oner of the important processes for preparation of high pure and ultra fine alumina. Kato and coworkers[1] developed this process, at same time Von Erdos and Altorfe[2] found AAHC in the corrosive products of aluminum in the atmosphere of carbon dioxide and ammonia. Murase and Iga[3] synthesized acicular AAHC in a autoclave under 60 to 12$0^{\circ}C$ Hayashi[4] optimized the conditions for preparation of AAHC and alumina. Attemp has been made in this paper to reveal the conditions affect the morphology of the synthesized AAHC and the consequently produced alumina.

• 한국환경보건학회지
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• 제21권3호
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• pp.96-101
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• 1995

A selective and highly sensitive spectrophotometric measurements have been developed for the determination of trace mercury(II) with thiosulfate and PAR. Hg(II)-thiosulfate complex was extracted into high molecular alkylamine such as quaternary ammonium salt and back extracted into 1 M-HCl solution. The Hg(II)-PAR complex has maximum absorbance at 499 nm and obeys Beer's law in the range of 0.04~1.0 $\mu g/mL$ of mercury(II). The molar absorptivity and Sandell's sensitivity are $6.27\times 10^4 L.mole^{-1} cm^{-1}$ and $3.2\times 10^{-3}g/cm^2$ respectively.

• Environmental Analysis Health and Toxicology
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• 제1권1호
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• pp.77-80
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• 1986

$N^{G}$ -Mono［$^{14}$ C-Methyl］-L-arginine을 방사선화학적 방법으로 mono ［$^{14}$ C］-Methylamine 으로부터 합성한후 양이온 교환수지에 흡착시킨 다음 암모니아수로 용출시켜 정제하였으며 flavianic acid를 사용하여 결정상태로 얻었다. 한편 flavianate와 음이온 교환수지 를 함께 실온 이하의 온도에서 교반혼합함으로서 유리 상태의 amino acid를 쉽게 만들수 있으며 박층크로마토그라피, 박층전기영동 및 섬광분광분석법으로 순도를 조사하였다.

• 한국식품영양과학회지
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• 제20권1호
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• pp.21-26
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• 1991

the Bacillus subtilis LY-353 which secretes the protease isolated from seafoods. The opti-mum culture condition for production of protease from B. subtilis LY-353 was as follows ; tem-perature 35$^{\circ}C$ pH 7.5 salt concentration 1.0% The purification steps involved ammonium sulfate fractionation DEAE-Sephadex A-50 column chromatography and Sephadex G-100 gel filtration A 7.33 fold purification and 6.55 yield of protease was obtained from culture broth, The optimum pH and temperature for the enzyme action were pH7.5 and 55$^{\circ}C$ respecti-bely.

• 한국염색가공학회지
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• 제15권6호
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• pp.47-54
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• 2003

To be dyed with cationic Berberine, the cotton fiber was modified with reactive anionic agent. The Berberine, a natural cationic colorant of pure yellow, is the major component of Amur Cork tree extract and also can be employed as a natural antimicrobial agent due to its characteristic of cationic quaternary ammonium salt. By LC/MS analysis, it became obvious that the Berberine was contained in Amur Cork tree extract as a major color component. The adsorption of the Berberine on the cotton fabrics pretreated with the anionic agent was greatly increased comparing to that of untreated fabric. Because the anionic agent was colorless, it did not cause unintended color change of the dyeings. The dyed fabric with the Berberine has strong antimicrobial activity showing 99.5% of reduction of bacteria against Staphylococcu aureus.

• Biotechnology and Bioprocess Engineering:BBE
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• 제6권4호
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• pp.279-283
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• 2001

Cationic lipid emulsion system consisting of 1, 2-dioleoyl-sn-slycero-3-trimethyl-ammonium-propane(DOTAP) and plasmin DNA with various counterions in the lipid headgroups were prepared. The transfection activity of the cationic lipid emulsion systems was then investigated in vitro and in vivo. The complex formation of plasmid DNA lipid emulsion was affected by the counterions through charged headgroup repulsion and also by the salt concen-tration in the media. As such , the transfection activity of the DOTAP emulsion system can be controlled by changing the counterions.

• Bulletin of the Korean Chemical Society
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• 제32권6호
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• pp.1936-1938
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• 2011

Phosphonium montmorillonites (P-MMTs) were prepared by intercalating dodecyl tributyl phosphonium salt into sodium montmorillonite (Na-MMT) through an ion-exchange method. Microstructure and antibacterial activity of phosphonium montmorillonites were studied by FT-IR, TGA, XRD and Minimum Inhibitory Concentration (MIC), respectively. The results show that phosphonium montmorillonites exhibit higher thermal stability than conventional ammonium montmorillonites, the onset temperature of decomposition is higher than 300 $^{\circ}C$, and the basal spacing of phosphonium montmorillonites is enlarged compared to that of sodium montmorillonite. Phosphonium montmorillonites also show good antibacterial activity with the MIC against E. coli and S. aureus of 150 and 50 $mg{\cdot}L^{-1}$, respectively.