• Bulletin of the Korean Chemical Society
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• v.33 no.7
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• pp.2325-2332
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• 2012

A series $[C_3Omim]$[X] of imidazolium cation-based ILs, with ether functional group on the alkyl side-chain have been synthesized and structure of the materials were confirmed by various techniques like $^1H$, $^{13}C$ NMR spectroscopy, MS-ESI, FTIR spectroscopy and EA. More specifically, the influence of changing the anion with same cation is carried out. The absorption capacity of $CO_2$ for ILs were evaluated at 30 and $50^{\circ}C$ at ambient pressure (0-1.6 bar). Ether functionalized ILs shows significantly high absorption capacity for $CO_2$. In general, the $CO_2$ absorption capacity of ILs increased with a rise in pressure and decreased when temperature was raised. The obtained results showed that absorption capacity reached about 0.9 mol $CO_2$ per mol of IL at $30^{\circ}C$. The most probable mechanism of interaction of $CO_2$ with ILs were investigated using FTIR spectroscopy, $^{13}C$ NMR spectroscopy and result shows that the absorption of $CO_2$ in ether functionalized ILs is a chemical process. The $CO_2$ absorption results and detailed study indicates the predominance of 1:1 mechanism, where the $CO_2$ reacts with one IL to form a carbamic acid. The $CO_2$ absorption capacity of ILs for different anions follows the trend: $BF_4$ < DCA < $PF_6$ < TfO < $Tf_2N$. Moreover, the as-synthesized ILs is selective, thermally stable, long life operational and can be recycled at a temperature of $70^{\circ}C$ or under vacuum and can be used repeatedly.

• Journal of the Korean Chemical Society
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• v.5 no.1
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• pp.38-41
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• 1961

By varying groups on biologically active molecules, it is possible to produce analogues which sometimes inhibit the action of the parent compound. Such is true of taurine(${\beta}$-amino-ethane sulfonic acid)as an analogue of ${\beta}$-alanine and of pantoyl taurine for pantothenic acid. It seemed possible that the sulfonic acid analogues of amino acids built into peptides might possibly produce inhibition of the parent peptide. Tauryl-L-histidine was selected to prepare as an analogue of carnosine(${\beta}$-alanyl-L-histidine). There were several reasons for this choice. Camosine causes a slight contraction of isolated uterine muscle and inhibition of this action can be easily tested. Also, taurine, being a ${\beta}$-amino sulfonic acid, is much more stable than the ${\beta}$-amino sulfonic acids. Phthalyl tauryl-L-histidine methyl ester was prepared by condensing phthalyl tauryl chloride with histidine methyl ester in chloroform. The yields were quite low possibly due to reaction between the acid chloride and the imidazole of histidine. Approximately 50 per cent yield of crude amorphous product was obtained, but upon purification by crystallization they yielded only 25 percent of a pure product. The methyl ester was removed by acid hydrolysis to prevent partial cleavage of the phthalyl group. Crystalline tauryl histidine was then obtained from this acid by removal of the phthalyl group by hydrazinolysis. Tests for inhibition were carried out by comparing the action of camosine on isolated uterine muscle before and after tauryl histidine had been added to the bath surrounding the muscle strip. Only in very high relative concentrations of tauryl histidine was there any demonstrable inhibition.

• Polymer(Korea)
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• v.33 no.6
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• pp.544-550
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• 2009

In this study, we have designed [Epoxy/PEG] polymer gel electrolyte systems by thermal curing the mixtures of epoxy, PEG, imidazole catalyst, and a plasticizer of 1:1 ethylene carbonate and propylene carbonate in the presence of $LiPF_6$ salt. In order to enhance the poor mechanical property of the Corresponding [Epoxy/PEG] gel electrolyte PVdF-HFP was incorporated into the system. The ionic conductivities of the polymer gel electrolytes were related to the amount of PVdF-HFP in blends as well as the amount of liquid electrolyte. The optimized gel system showed room-temperature conductivities of $2.56\times10^{-3}S/cm$.

• Preventive Nutrition and Food Science
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• v.18 no.4
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• pp.263-268
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• 2013

In this study, the quick HPLC-MS/MS method for the simultaneous separation of 2-acetyl-4(5)-tetrahydroxybuthylimidazole (THI) and 4-(5)-methylimidazole (4-MI) in alkaline medium was used for caramel color and processed foods in Korea. After a simple sample pretreatment, 51 4-MI-labeled samples were positive for 4-MI and 2 also contained THI. The concentration of 4-MI was 260.5~24, $499.3{\mu}g/kg$ in caramel color, less than $LOD{\sim}1,712.5{\mu}g/kg$ in sauce, 1,242.3, $5,972.2{\mu}g/kg$ in balsamic vinegar, $2,118.3{\sim}5,802.4{\mu}g/kg$ in complex seasoning, $82.7{\sim}5,110.6{\mu}g/kg$ in curry, and $29.9{\sim}464.4{\mu}g/kg$ in soft drinks. The recovery rate of 4-MI was 97.1~111.0% in sauce and 81.9~110.0% in powder and that of THI was 83.6{\sim}106.4% in sauce and 61.2{\sim}99.4% in powder. Our results concluded a safe amount of 4-MI and THI compared to the limit of Korea additive code but the processed foods do not have a limit of caramel color and 4-MI in Korea. Therefore, research and monitoring of 4-MI and THI is needed for processed foods in Korea.

• Applied Biological Chemistry
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• v.37 no.5
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• pp.356-360
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• 1994

The optimum pH and temperature for endo-polygalacturonase activity from Jujube were 5.0 and $50^{\circ}C$. The range of its stability to pH was 4.0 to 5.0. The enzyme was inactivated about 35% by treatment at $70^{\circ}C$ for 1 hr. It was found that $Ag^+$, $Zn^{++}$ and $Mg^{++}$ increased the enzyme activity. In contrast, $Ba^{++}$, $Hg^{++}$, $Pb^{++}$, $Ca^{++}$, $Mn^{++}$, $Cu^{++}$, $Fe^{+++}$, $Na^+$ and $K^+$ decreased it. The enzyme was inactivated by treatment with maleic anhydride, iodine and 2,4-dinitrophenol. The results indicate that active site is a imidazole group on the enzyme.

• Korean Journal of Materials Research
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• v.7 no.3
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• pp.244-250
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• 1997

본 연구에서는 에폭시/산무수물계에 경화촉진제를 첨가한 시료를 몰드(mold)내에서 등온 경화시킬 때 시료 내부의 온도변화를 측정하여 얻어진 온도-시간 곡선(temperature-time profile)을 조사하였다. 실험에 사용한 경화촉진제의 종류는 1-cyanoethy1-2-ethy1-4-methy1 imidazole(1E4MZ-CN), N,N-dimethy1 benzy1 amine(BDMA), 2,4,6-tris(dimethy1-aminomethy1)-phenol(DMP-30)이며 그들의 농도(c)는 1.0,1.5,2.0,2.5,phr그리고 경화온도(T$_{cure}$ )는 65,70,85,95$^{\circ}C$로 하였다. 경화가 진행되는 동안 시료내부의 온도는 초기에 경화온도로 상승한 후 본격적인 경화 반응이 일어나기 시작하여 온도가 급격히 상승하였다가 다시 감소하는 양상을 보였다. 온도-시간 곡선상에 나타나는 온도가 최고로 상승되는 시점(t$_{peak}$ )과 그 때의 온도(T$_{peak}$ )는 촉진제의 종류와 농도 그리고 경화온도에 의하여 영향을 받았다. 사용한 경화촉진제중에 DMP-30이 가장 짧은 t$^{peak}$ 값을 가져 가장 우수한 촉진 효과를 갖는 것으로 나타났으며, T$_{peak}$ 는 촉진제의 농도와 경화온도가 증가할수록 상승하였다. 그리고 경화촉진제의 농도와 경화온도의 변화에 따른 t$_{peak}$ 과 T$_{peak}$ 의 변화를 보면 촉진제 농도와 경화온도가 낮을 때 그 변화가 민감하여 2E4MZ-CN 이 가장 민감한 촉진제로 나타났으며 또한 T$_{peak}$ 에 영향을 주는 여러가지 요소들을 본 연구에서 얻어진 결과로부터 자세히 살펴보았다.

• Molecules and Cells
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• v.43 no.9
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• pp.784-792
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• 2020

Arginine kinase (AK), a bioenergy-related enzyme, is distributed widely in invertebrates. The role of highly conserved histidines in AKs is still unascertained. In this study, the highly conserved histidine 284 (H284) in AK of Daphnia magna (DmAK) was replaced with alanine to elucidate the role of H284. We examined the alteration of catalytic activity and structural changes of H284A in DmAK. The catalytic activity of H284A was reduced dramatically compared to that in wild type (WT). Thus the crystal structure of H284A displayed several structural changes, including the alteration of D324, a hydrogen-bonding network around H284, and the disruption of π-stacking between the imidazole group of the H284 residue and the adenine ring of ATP. These findings suggest that such alterations might affect a conformational change of the specific loop consisting of G310-V322 at the antiparallel β-sheet region. Thus, we speculated that the H284 residue might play an important role in the conformational change of the specific loop when ATP binds to the substrate-binding site of DmAK.

• Journal of Radiation Industry
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• v.4 no.1
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• pp.7-11
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• 2010

Clotrimazole [1-{(2-chlorophenyl)-diphenylmethyl}-1H-imidazole, CLT] has been reported to inhibit the proliferation of vascular endothelial and act as an in vitro anti-VEGF drug. It is also shown to inhibit angiogenesis in an animal model. The radioisotope labeled clotrimazole derivative can be utilized to monitor the physiologic processes of cancer. In this study, we synthesized [$^{18}F$]fluoride labeled clotrimazole derivatives as a new tumor imaging agent for PET. The references were prepared by a refluxing with clotrimazole and an excess of fluoroalkyltosylate in acetonitrile for 36 h and clotrimazole reacted with ditosylalkane to give precursors. [$^{18}F$]Fluoride labeled reaction was performed with precursor in Kryptofix[2.2.2]/$K_2CO_3$ for 10 min at $80^{\circ}C$. The radiolabeling mixture was passed through a silica Sep-Pak cartridge to remove $^{18}F^-$. The [$^{18}F$]F-clotrimazole derivatives were synthesized with a 20~25% yield. In the radiofluorination step, we used acetonitrile and DMSO as a solvent and observed a higher yield at the acetonitrile (25%) reaction compared with the DMSO reaction (5%).

• Journal of Veterinary Science
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• v.22 no.1
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• pp.4.1-4.13
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• 2021

Background: Microsporum canis is a zoonotic disease that can cause dermatophytosis in animals and humans. Objectives: In clinical practice, ketoconazole (KTZ) and other imidazole drugs are commonly used to treat M. canis infection, but its molecular mechanism is not completely understood. The antifungal mechanism of KTZ needs to be studied in detail. Methods: In this study, one strain of fungi was isolated from a canine suffering with clinical dermatosis and confirmed as M. canis by morphological observation and sequencing analysis. The clinically isolated M. canis was treated with KTZ and transcriptome sequencing was performed to identify differentially expressed genes in M. canis exposed to KTZ compared with those unexposed thereto. Results: At half-inhibitory concentration (½MIC), compared with the control group, 453 genes were significantly up-regulated and 326 genes were significantly down-regulated (p < 0.05). Quantitative reverse transcription polymerase chain reaction analysis verified the transcriptome results of RNA sequencing. Gene ontology enrichment analysis and Kyoto Encyclopedia of Genes and Genomes enrichment analysis revealed that the 3 pathways of RNA polymerase, steroid biosynthesis, and ribosome biogenesis in eukaryotes are closely related to the antifungal mechanism of KTZ. Conclusions: The results indicated that KTZ may change cell membrane permeability, destroy the cell wall, and inhibit mitosis and transcriptional regulation through CYP51, SQL, ERG6, ATM, ABCB1, SC, KER33, RPA1, and RNP genes in the 3 pathways. This study provides a new theoretical basis for the effective control of M. canis infection and the effect of KTZ on fungi.

• Journal of the Korean institute of surface engineering
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• v.55 no.2
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• pp.51-62
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• 2022

Metal-organic framework (MOF) is one of the representative porous materials composed of metal ions and organic linkers. In spite of many advantages of the MOFs such as high specific surface area and ease of structure control, drawbacks have become obstacles to the practical use of them with poor electrical conductivity and chemical stability. The ZIF-8, which is consisted of zinc and imidazole linker, is one of the solutions to improve the chemical stability issue. In addition, composites using the ZIF-8 and carbonbased materials are widely used to enhance the electrical conductivity. In this regard, supercapacitor is very attractive field for using the composites, because most of carbon-based materials are porous and conductive. Also, for sensor applications, the ZIF-8 composite is suitable material to meet the requirement in terms of the selectivity and sensitivity. This review summarizes recent progress of the composite materials with the ZIF-8 and the carbon-based materials for the supercapacitors and the chemical sensors. In particular, the composites are classified into ZIF-8-graphene, ZIF-8-carbon nanotube and ZIF-8-other carbon-based material.