• Archives of Pharmacal Research
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• v.9 no.2
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• pp.81-86
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• 1986

The effect of imperatorin on hepatic microsomal mixed function oxidases (MF0) was investigated. On acute treatment, imperatorin (30 mg/kg, i.p) caused a significant reduction in activities of hepatic aminopyrine N-demethylase, hexobarbital hydroxylase and aniline hydroxylase as well as cytochrome p0450 content in rats and mice. Kinetic studies on rat liver enzymes revealed that imperatorin appeared to be a competitive inhibitor of aminopyrine N-demethylase (Ki,0.007 mM), whereas a non-competitive inhibitor of hexobarbital hydroxylase (Ki, 0.0148 mM). Imperatorin also inhibited non-competitively aniline metabolism (Ki 0.2 mM). Imperatorin binds to phenobarbital-induced cytochrome p-450 to give a typical type 1 binding sepctrum (max. 388nm, min 422 nm). Multiple administrations of imperatorin (30 mg/kg. i. p. daily for 7 days) to mice shortended markedly the duration of hexobarbital narcosis and increased activities of hepatic aminopyrine N-demethylase and hexobarbital hydroxylase and the level of cytochrome p-450 where as aniline hydroxylase activity was unaffected.

• Bulletin of the Korean Chemical Society
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• v.4 no.2
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• pp.72-76
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• 1983

Cephaloglycin was synthesized directly from D-${\alpha}$ -phenylglycine methyl ester and 7-aminocephalosporanic acid using whole cell enzyme of Xanthomonas citri (IFO 3835). Some optimal conditions for cephaloglycin synthesis were investigated, and yield improvements for its production by several methods were attempted. Using the whole cell enzyme system, the reaction kinetic model for cephaloglycin synthesis is proposed, and the kinetic constants for D-${\alpha}$ -phenylglycine methyl ester hydrolysis, cephaloglycin synthesis, and cephaloglycin hydrolysis were determined. The $K_m$ values of D-${\alpha}$-phenylglycine methyl ester, 7-aminocephalosporanic acid, and cephaloglycin were 11 mM, 24 mM, and 167 mM, and $K_i$ value of D-${\alpha}$-phenylglycine was 15 mM, respectively. The pattern of product inhibition was found to be competitive one.

• Bulletin of the Korean Chemical Society
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• v.22 no.8
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• pp.850-856
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• 2001

This study investigates the ozonation kinetics of 2-chlorophenol in wastewater under acidic condition. Intermediates and by-products generated during the process were rigorously identified and quantified. The major by-products are four carboxylic acids: tartaric acid, oxalic acid, maleic acid, and hydroxymalonic acid. The generation of these organic acids is in agreement with theoretical predictions. But hydroxylated compounds are more favorable to produce than their corresponding non-hydroxylated ones. Based on the information concerning the generation of organic acids and other aromatic intermediates, the complete reaction pathways toward mineralization can be proposed and mathematically modeled. The fitted second-order rate constants are in the same order of magnitude with the results from other studies. Using these oxidation pathways and the corresponding kinetic model, by-products generated in ozonation process can be predicted. This can help in optimizing the design and operation of any subsequent treatment processes.

• Bulletin of the Korean Chemical Society
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• v.11 no.5
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• pp.435-438
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• 1990

Primary and secondary ${\alpha}$-deuterium kinetic isotope effects are determined with deuterated aniline nucleophiles in the nucleophilic substitution reactions of benzyl benzenesulfonates and 1-phenylethyl benzenesulfonates in acetonitrile at 30.0^{\circ}C. The $k_H/k_D$ values support our previous conclusions regarding the transition state structures proposed for the two reactions based on the cross-interaction constants ${\rho}_{ij}$; the former is a typical $S_N2$ reaction whereas in the latter the four-center transition state may be involved.

• Journal of the Korean Chemical Society
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• v.63 no.4
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• pp.233-236
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• 2019

In this study, the solvolysis of cyclohexanesulfonyl chloride (1) was studied by kinetics in ethanol-water, methanol-water, acetone-water, and 2,2,2-trifluoroethanol (TFE)-water binary solvent systems. The rate constants were applied to the extended Grunwald-Winstein equation, to obtain the values of m = 0.41 and l = 0.81. These values suggested $S_N2$ mechanism in which bond formation is more important than bond breaking in the transition state (TS). Relatively small activation enthalpy values (11.6 to $14.8kcal{\cdot}mol^{-1}$), the large negative activation entropy values (-29.7 to $-38.7cal{\cdot}mol^{-1}{\cdot}K^{-1}$) and the solvent kinetic isotope effects (SKIE, 2.29, 2.30), the solvolyses of the cyclohexanesulfonyl chloride (1) proceeds via the $S_N2$ mechanism.

• Journal of Industrial and Engineering Chemistry
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• v.67
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• pp.109-122
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• 2018

This work highlights extraction and removal of Lignosulfonate using sunflower oil-Tri-n-octylamine (TOA) system in bulk liquid membrane transport. Maximum extraction and recovery percentages of 92.4% and 75.2% were achieved. Optimum manifold operating conditions were: 4 vol.% TOA, $2{\pm}0.1$ feed phase pH, 300 rpm stirring speed, at $40^{\circ}C$ with 0.2 (M) $Na_2SO_4$ solution. 1:2 (organic/aqueous) and 1:1 (aqueous/aqueous) phase ratios produced best results. Extraction (36.85 kJ/mol) was found to be intermediate controlled and stripping (54.79 kJ/mol) was chemical reaction controlled. Kinetic estimation of data with higher rate constants for stripping vis-${\grave{a}}$-vis extraction showed latter to be rate determining.

• Bulletin of the Korean Chemical Society
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• v.27 no.5
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• pp.733-738
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• 2006

Nucleophilic addition reactions of p-substitutedbenzylamines $(XC _6H_4CH _2NH _2)$ to $\alpha$-phenyl-$\beta$-thiophenyl-acrylonitriles ($YC _4SH _2CH=C(CN)C_6H_4$Y') have been studied in acetonitrile at 25.0, 30.0, and 35.0 ${^{\circ}C}$. The reactions take place in single step in which the $C_\beta$ -N bond formation and proton transfer to $C_\alpha$ of $\alpha$-phenyl-$\beta$-thiophenylacrylonitriles occur concurrently with four-membered cyclic transition structure. These mechanistic conclusions are drawn based on (i) the large negative $\rho$x and large positive $\rho$Y' values and also large magnitude of $\rho$X, (ii) the negative sign and large magnitude of the cross-interaction constants ($\rho$XY), (iii) the normal kinetic isotope effects ($k_H/k_D$ > 1.0), and (iv) relatively low $\Delta H ^\neq$ and large negative $\Delta S ^\neq$ values.

• BMB Reports
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• v.32 no.5
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• pp.429-435
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• 1999

Unlike the mammalian glucose transporter GLUT1, little is known about the nature of the endogenous sugar transporter(s) in insect cells. In order to establish the transport characteristics and other properties of the sugar transport proteins of Sf9 cells, a series of kinetic analyses was performed. A saturable transport system for hexose uptake has been revealed in the insect cells. The apparent affinity of this transport system(s) for 2-deoxy-D-glucose was relatively high, the $K_m$ for uptake being <0.5 mM. To further investigate the substrate and inhibitor recognition properties of the insect cell transporter, the ability of other sugars or drugs to inhibit 2-deoxy-D-glucose transport was examined by measuring inhibition constants ($K_j$). Transport was inhibited by D-mannose, D-glucose, and D-fructose. However, the apparent affinity of the C-4 epimer, D-galactose, for the Spodoptera transporter was relatively low, implying that the hydroxyl group at the C-4 position may play a role in the strong binding of glucose and mannose to the transporter. The results also showed that transport was stereoselective, being inhibited by D-glucose but not by L-glucose. It is therefore concluded that insect cells contain an endogenous glucose transport activity that in several aspects resembles the human erythrocyte glucose transporter. However, the mammalian and insect transporters were different in some of their kinetic properties, namely, their affinities for fructose and for cytochalasin B.

• Advances in environmental research
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• v.3 no.1
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• pp.29-43
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• 2014

Pharmaceutical wastewater effluents are well known for their difficult elimination by traditional biotreatment methods and their important contribution to environmental pollution due to its fluctuating and recalcitrant nature. OTC is one of the nonbiodegradable antibiotics that makes antibiotic-resistant, so it can make be high risk for environment. NZVI can be a good choice for removal of OTC in aqueous solution. Response surface methodology (RSM) was used to optimize the amounts of NZVI and OTC to be used at pH 3 and under 200 W, UV-A irradiation. The responses were removal percent of absorption at 290 and 348 nm, TOC and COD of OTC. In the optimum condition, Linear model was performed 155 ppm of OTC were removed by 1000 ppm NZVI after 6.5 hours and the removal efficiency of absorption at 290 and 348 nm, TOC and COD were 87, 95, 85 and 89 percent, respectively. In the similar process, there is no organic compound after 14 hours. The parameters ORP, DO and pH were investigated for 6:30 hours to study the type of NZVI reaction in process. In the beginning of reaction, oxidation was the dominant reaction after 3 hours, photocatalytic reaction was remarkable. The mechanism of OTC degradation is proposed by HPLC/ESI-MS and four by products were found. Also the rate constants (first order kinetic chain reaction model) were 0.0099, 0.0021, 0.0010, 0.0049 and $0.0074min^{-1}$, respectively.

• Bulletin of the Korean Chemical Society
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• v.34 no.12
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• pp.3597-3601
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• 2013

The reactions of bis(Y-aryl) chlorothiophosphates (1) with substituted anilines and deuterated anilines are investigated kinetically in acetonitrile at $55.0^{\circ}C$. The Hammett plots for substituent Y variations in the substrates show biphasic concave upwards with a break point at Y = H. The cross-interaction constants (${\rho}_{XY}$) are positive for both electron-donating and electron-withdrawing Y substituents. The kinetic results of 1 are compared with those of Y-aryl phenyl chlorothiophosphates (2). The cross-interaction between Y and Y, due to additional substituent Y, is significant enough to result in the change of the sign of ${\rho}_{XY}$ from negative with 2 to positive with 1. The effect of the cross-interaction between Y and Y on the rate changes from negative role with electron-donating Y substituents to positive role with electron-withdrawing Y substituents, resulting in biphasic concave upward free energy correlation with Y. A stepwise mechanism with a rate-limiting leaving group departure from the intermediate involving a predominant frontside attack hydrogen bonded, four-center-type transition state is proposed based on the positive sign of ${\rho}_{XY}$ and primary normal deuterium kinetic isotope effects.