• Bulletin of the Korean Chemical Society
• /
• 제30권12호
• /
• pp.3031-3033
• /
• 2009

A new colorimetric anion sensor 1 has been synthesized based on both Fat brown RR dye and a nitrophenyl group. This new receptor 1 could recognize the presence of fluoride ion effectively and selectively by the change of color of solution. In addition, receptor 1 shows higher affinity for acetate, dihydrogenphosphate, and hydrogensulfate than the other anions such as chloride, bromide, iodide, perchlorate, and nitrate in acetonitrile.

• Bulletin of the Korean Chemical Society
• /
• 제15권5호
• /
• pp.390-393
• /
• 1994

Details on the electrochemical formation of lead dioxide from aqueous plumbous ion are studied by measuring current-time behavior with potential step method at a rotating platinum electrode. A cubic law without induction period can be applied to the crystallization of lead dioxide in both acetate and nitrate media. In the course of the mechanistic study, the presence of a soluble intermediate during the nucleation step is clearly observed with a rotating ring-disk electrode. Decrease in the anodic ring current due to the reduction of soluble species formed during the anodic crystallization of lead dioxide at disk is detected.

• 한국재료학회지
• /
• 제33권12호
• /
• pp.550-557
• /
• 2023

In zinc-air batteries, the gel polymer electrolyte (GPE) is an important factor for improving performance. The rigid physical properties of polyvinyl alcohol reduce ionic conductivity, which degrades the performance of the batteries. Zinc acetate is an effective additive that can increase ionic conductivity by weakening the bonding structure of polyvinyl alcohol. In this study, polymer electrolytes were prepared by mixing polyvinyl alcohol and zinc acetate dihydride. The material properties of the prepared polymer electrolytes were analyzed by Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). Also, Electrochemical impedance spectroscopy was used to calculate ionic conductivity. The electrolyte resistances of GPE, 0.2 GPE, 0.4 GPE, and 0.6 GPE were 0.394, 0.338, 0.290, and 0.213 Ω, respectively. In addition, 0.6 GPE delivered 0.023 S/cm high ionic conductivity. Among all of the polymer electrolytes tested, 0.6 GPE showed enhanced cycle life performance and the highest specific discharge capacity of 11.73 mAh/cm² at 10 mA. These results verified that 0.6 GPE improves the performance of zinc-air batteries.

• 한국자원식물학회:학술대회논문집
• /
• 한국자원식물학회 2018년도 춘계학술발표회
• /
• pp.14-14
• /
• 2018

This Camptotheca acuminata Decne. (CA), belonging to Nyssaceae, is a deciduous tree. and has been used as Traditional Chinese medicine since ancient times. The CA produces camptothecin a natural indole alkaloid, and reported to have anti-cancer effects. But the studies on biological activities of CA leaves are insufficient. Therefore, this study confirmed various biological activities such as antioxidant, antidiabetic, anticancer, antiinflammatory and metabolism analysis by HPLC-MS/MS of CA leaves. The $RC_{50}$ values of DPPH radical scavenging activity of ethyl acetate fraction, n-Butanol fraction, methanol extraction, water fraction and n-Hexane fraction were $12.23{\pm}0.01$, $15.93{\pm}0.42$, $55.12{\pm}0.45$, $56.29{\pm}4.15$ and $427.29{\pm}6.13ug/mL$, respectively. The $IC_{50}$ values of ${\alpha}$-glucosidase inhibitory activity of ethyl acetate fraction, n-Butanol fraction, methanol extraction, n-Hexane fraction and water fraction were $24.29{\pm}0.14$, $47.86{\pm}0.45$, $54.23{\pm}1.21$ $466.76{\pm}2.21$ and $623.91{\pm}9.67ug/mL$, respectively. The nitric oxide release activity of n-Hexane fraction, methanol extraction, ethyl acetate fraction, water fraction and n-Butanol fraction were $31.49{\pm}5.74$, $29.79{\pm}0.71$, $26.89{\pm}0.71$, $8.24{\pm}5.83$ and $7.75{\pm}4.08%$ at 25 ug/mL, respectively. The anti-cancer activity of n-Hexane fraction, methanol extraction, ethyl acetate fraction, water fraction and n-Butanol fraction were $31.49{\pm}5.74$, $29.79{\pm}0.71$, $26.89{\pm}0.71$, $8.24{\pm}5.83$ and $7.75{\pm}4.08%$ at 25 ug/mL, respectively. The ethyl acetate fraction activities showed higher biological activities than other fractions. Thus, Additional studies were conducted using ethyl acetate fraction. Metabolite analysis was performed using a LCMS-8040 triple quadrupole mass spectrometer. As a result, Five compounds (1-5) were identified in the ethyl acetate fraction of the CA leave. The identification of these compounds was generated by the analysis of fragmentation methods of the negative and positive ion modes. Five compounds were identified as gallic acid (1), chlorogenic acid (2), isoquercetin (3), astragalin (4) and camptothecin (5). These results suggest that the CA leave can be used for functional materials.

• The Korean Journal of Physiology and Pharmacology
• /
• 제8권5호
• /
• pp.259-264
• /
• 2004

Cytolysin produced by Vibrio vulnificus has been incriminated as one of the important virulence determinants in V. vulnificus infection. Ion selectivity of cytolysin-induced pores was examined in a CPAE cell, a cell line of pulmonary endothelial cell, using inside-out patch clamp techniques. In symmetrical NaCl concentration (140 mM), intracellular or extracellular application of cytolysin formed ion-permeable pores with a single channel conductance of $37.5{\pm}4.0$ pS. The pore currents were consistently maintained after washout of cytolysin. Replacement of $Na^+$ in bath solution with monovalent ions $(K^+,\;Cs^+\;or\;TEA^+)$ or with divalent ions $(Mg^{2+},\;Ca^{2+})$ did not affect the pore currents. When the NaCl concentration in bath solution was lowered from 140 to 60 and 20 mM, the reversal potential shifted from 0 to -11.8 and -28.2 mV, respectively. The relative permeability of the cytolysin pores to anions measured at $-40\;mV\;was\;Cl^-\;=\;NO_2^-\;{\geq}\;Br^-\;=\;I^-\;> \;SCN^-\;>\;acetate^-\;>\;isethionate^-\;>\;ascorbic acid^-\;>\;EDTA^{2-},$ in descending order. The cytolysin-induced pore current was blocked by $CI^-$ channel blockers or nucleotides. These results indicate that V. vulnificus cytolysin forms anion-selective pores in CPAE cells.

• 한국미생물·생명공학회지
• /
• 제19권2호
• /
• pp.153-157
• /
• 1991

Intracellular enzymes of an extreme halophilic bacterium, Halobacterium sp. HE10, isolated from a saltern in Korea was investigated. The membrane-bound enzyme, NADH dehydrogenase, involved in electron transport system was stimulated by the addition of 2.0 M NaCl. The respiratory enzyme activities such as NADH oxidase and NADH dehydrogenase was decreased on removal of $Na^+$ ion and restored when replaced with cations like $K^+$, $Li^+$and $NH_{4}^{+}$ ions. Furthermore, their activities were affected by the anions such like carbonate, acetate, sulfate, chloride and nitrate at the presence of $Na^+$ion. Lactate dehydrogenase activity was highest at the asturated solution of NaCl and isocitrate dehydrogenase activity was a maximum level at 1.0 M NaCl. These results suggested that the enzyme activites of the respiratory chain in Halobacterium sp. EH10 was stimulated by the presence of $Na^+$ ion.

• 약학회지
• /
• 제34권3호
• /
• pp.215-218
• /
• 1990

An ion chromatographic method based on indirect photometric detection of UV transparent anions was developed. Separation of anion was accomplished on strong anion exchange column (Waters SAX) using UV detector at 254 nm. Among examined UV-active additives (Dns-H, Dns-glu, Dnsser, Dns-val), Dns-glu showed the highest sensitivity. Studies on the effects of the pH and ionic strength of eluent revealed that the increase of pH and ionic strength of the eluent decreased capacity factor. The best eluent for the separation of acetate, fluoride, chloride, nitrate and bromide was $1\;{\times}\;10^{-4}M$ Dns-glu in 5 mM phosphate buffer (pH 6.30). The detection limit of chloride ion was 2.1 ng in this condition.

• 한국미생물·생명공학회지
• /
• 제22권5호
• /
• pp.507-514
• /
• 1994

Acetyl xylan esterase was produced by E. coli HB101 harboring a recombinant plasmid pKMG6 which contained the estI gene of Bacillus stearothermophilus. The maximum production was observed when the E. coli strain was grown at 37$\circC for 12 hours in the medium containing 0.5% acetyl xylan, 1.0% tryptons, 1.0% sodium chloride, and 0.5% yeast extract. The esterase produced was purified to homogeneity using a combination of ammonium sulfate fractionation, DEAE Sepharose CL-6B ion exchange chromatography and Sephacryl S-200 gel filtration. The native enzyme had an apparent molecular mass of 60 kd and was composed of two identical subunits of 29 kd. The N-terminal amino acid sequence of the polypeptide was Ala-X-Leu-Gln- Ile-Gln-Phe-X-X-Gln. The acetyl esterase displayed a pH optimum of 6.5 and a temperature opti- mum of 45$\circC. The heavy metal ions such as Ag$^{++}$, Hg$^{++}$ and Cu$^{++}$ inhibited nearly completely the activity of the esterase, and no specific metal ion was found to be required for the enzyme activity. The enzyme readily cleaved MAS, $\beta$-D-glucose pentaacetate, $\alpha$-naphthyl acetate, $\rho$-nitrophenyl acetate as well as acetyl xylan, but had no activity on $\rho$-nitrophenyl propionate, $\beta$-nitrophenyl butyrate or $\beta$-nitrophenyl valerate. The Km and Vmax values for MAS were 2.87 mM and 11.55 $\mu$mole/min, respectively. Synergistic behavior was demonstrated with a combination of xylanase and esterase from B. stearothermophilus in hydrolyzing acetyl xylan.

• 분석과학
• /
• 제11권3호
• /
• pp.213-221
• /
• 1998

Bromide, chloride, fluoride, nitrite, nitrate, sulfite, sulfate, perchlorate, chlorate 및 chlorite가 포함된 시료를 capillary zone electrophoresis(CZE)와 indirect UV detection 방법으로 분리하였다. 음이온류의 분리는 running buffer로 5 mM ammonium dichromate, 10 mM ammonium acetate, 20 mM diethylenetriamine, 10% methanol(pH 9.3)을 사용하였으며 전압은 cathode에 15 kV를 공급하였다. 또한 최초로 CZE에서 음이온의 정량이 가능하도록 각 이온들에 대한 regression과 detection limit를 결정하였고, 이 분석방법은 톨루엔을 흡입한 사람의 뇨, 부검 혈액, 폐수 및 폭약 등 시료에 적용하였으며, 음이온의 함량을 ion chromatograph(IC)와 비교 검토하였다.

• 자원리싸이클링
• /
• 제11권3호
• /
• pp.3-9
• /
• 2002

제오라이트와 벤토나이트 시료를 사용하여 누용액중의 암모니아 성분을 제거하기 위한 실험을 수행하였다. 실점에 사용한 제오라이트와 벤토나이트 분말은 국내업체에서 제공한 시료를 별도의 정제과정을 거치지 않고 사용하였다. 수용액 pH측정결과 암모니아 수용액의 초기 pH 5.5~5.7에서 제오라이트 혹은 벤토나이트 첨가시 pH 가 상승하어 최대 pH 8.5까지 증가하는 현상이 관찰되었다. ammonium acetate 용액을 사용한 침출법으로 제오라이트와 벤토나이트의 C.E.C.를 측정한 결과 제오라이트는 129.7 meq/100gr을 또한 벤토나이트는 65.1 meq/100 gr의 수치를 나타냈으며, 두 경우 모두 $Na^{+}$ 이온이 전체 C.E.C. 중 가장 많은 부분을 차지하였다. 제오근라이트와 벤토나이트에 의한 암모니아 제거시 순수 이온교환반웅에 의한 것과 함께 물리적 흡착에 의한 암모니아 제거현상도 동시에 나타나는 것으로 관찰되었으며, 벤토나이트 보다는 제오라이트에 의한 수용액중 암모니아 제거가 보다 효과적이었다.