• Journal of the Korean Chemical Society
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• v.58 no.1
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• pp.57-61
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• 2014

The 4-(1H)-benzotriazoyl methyl amino benzoate 3 was prepared by Mannich reaction of benzotriazole 1, ethyl-paminobenzoate 2 and formaldehyde. The prepared compound 3 then react with hydrazine hydrate results in the 4-(1H)-benzotriazoyl methyl amino benzoyl hydrazide 4. This compound on condensation with pre-prepared different ethyl 2-(2-(4-(4-substituted phenyl)thiazol-2-yl)hydrazono)-3-oxobutanoates 6a-d, furnished 1-(4-((1H-benzo[d] [1,2,3] triazol-1-yl)methyl amino) benzoyl)-4-(2-(4-(4-substituted phenyl)thiazol-2-yl) hydrazono)-3-methyl-1H-pyrazol-5(4H)-one 7a-d. All the compounds 7a-d was characterized by spectral studies. The compounds showed significant antimicrobial activity against various bacteria and fungi.

• Korean Journal of Microbiology
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• v.8 no.2
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• pp.85-89
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• 1970

Effects of the sugar content in molasses media and pH on cell constituents of produced yeast adopting Saccharomyces cerevisiae Rasse O as a seed organism were studied, and following results were obtained. 1. Trehalose accumulation of the yeast was reduced at lower range of pH, however protein was increased. 2. Trehalose content of the yeast enriched by feeding increased sugar at suitable pH. 3. There was no significant increase of thehalose content in the cell by feeding concentrated molasses at lower range of pH.

• Macromolecular Research
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• v.16 no.8
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• pp.670-675
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• 2008

A series of pH and temperature-responsive (N,N-diethylacrylamide-co-methylacrylic acid) copolymers were synthesized by radical copolymerization and characterized by elemental analysis, Fourier-transform infrared (FT-IR), nuclear magnetic resonance (NMR) $^1H$, $^{13}C$ and LLS. The effects of salt and pH on the phase transition behaviors of the copolymers were investigated by uv. With increasing NaCl concentration, significant salt effects on their phase transition behaviors were observed. UV spectroscopic studies showed that the phase transition became faster with increasing NaCl concentration. In addition, the phase transition behaviors of copolymers were sensitive to pH. The pH and temperature sensitivity of these copolymers would make an interesting drug delivery system.

• Korean Journal of Environmental Agriculture
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• v.24 no.2
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• pp.159-163
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• 2005

This study was conducted to investigate the effect of simulated acid rain (SAR) on growth and antioxidant system in french marigold (Tagetes patula L.). Plants were subjected to four levels of SAR (pH 5.6, 4.0, 3.0, 2.0) in the growth chambers for 2 weeks. SAR decreased both plant height and plant dry weight of french marigold. As the pH levels decreased from 5.6 to 2.0, the content of MDA highly increased linearly. The ratios of dehydroascorbate/ascorbate and oxidized glutathione/reduced glutathione were significantly increased with decreasing pH levels. The enzyme (superoxide dismutase, ascorbate peroxidase etc.) activities of the plant affected by SAR were increased as the pH decreased. Based on the results, SAR caused oxidative stress in french marigold and resulted in significant reduction in plant growth. Biochemical protection responses might be activated to prevent the plant from damaging effects of oxidative stress generated in SAR.

• Resources Recycling
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• v.10 no.4
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• pp.10-17
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• 2001

The present work investigates the possible use of fly ash for the removal of heavy metal ions from aqueous solutions. Batch experiments were conducted and the influences of metal concentration, pH, and fly ash concentration were investigated. Heavy metals used in these studies were lead and zinc. Adsorption studies were done over a range of pH values (3~10) at $25^{\circ}C$ and heavy metal concentrations of 10~400 mg/L using fly ash concentrations of 10 and 20 g/L. Experiments were also conducted without fly ash to determine the extent of heavy metal removal by precipitation. Kinetic and equilibrium experiments were performed and adsorption data were correlated with both Langmuir and Freundlich adsorption models. The results of these studies indicate that 리y ash can be used as an adsorbent for heavy metals in the aqueous solutions, yet the degree of removal depends on the pH.

• Bulletin of the Korean Chemical Society
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• v.32 no.9
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• pp.3411-3420
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• 2011

Kinetic and structural studies have been carried out on the effects of meso-tetrakis(4-sulfonatophenyl)-porphyrin ($H_2TPPS_4$) as an anionic and meso-tetrakis(3-N-methyl-pyridyl)porphyrin ($H_2TMPYP$) as a cationic porphyrin with adenosine deaminase (ADA) in 25 mM citrate/phosphate buffer, pH = 4-8, at $37^{\circ}C$ using UVvis spectrophotometry, circular dichroism (CD), fluorescence spectrophotometry as well as molecular dynamics (MD) and molecular docking. Kinetic results showed that the two porphyrins are non-competitive inhibitors. Increasing pH, increases $K_I$ and cationic porphyrin has a higher $K_I$ and lower binding constant ($K_b$) at all pH ranges. Analyzing the secondary structure revealed that both ligands decrease the secondary structure and that the anionic porphyrin is more effective.

• Bulletin of the Korean Chemical Society
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• v.18 no.4
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• pp.374-379
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• 1997

The rate constants for the nucleophilic addition of thiophenol derivatives (p-OCH3, H, p-CH3, m-CH3, p-Br and p-NO2) to 4'-[N-(9-acridinyl)]-1'-(N-methanesulfonyl)-3'-methoxyquinonediimide (AMQD) were determined by ultraviolet spectrophotometer in water at 5 ℃, and rate equations which can be applied over a wide pH range were obtained. On the basis of pH-rate profile, Bronsted plot, adduct analysis, general base catalysis and substituent effect, a plausible mechanism of this addition reaction was proposed: Below pH 2.5, the reaction proceeded by the addition of thiophenol molecule to 6'-position of quinonoid after protonation at the acridinyl nitrogen. Above pH 6.2, the addition of sulfide anion to 6'-position of quinonoid was rate controlling. However, in the range of pH 3.0-6.0, these two reactions occured competively.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.2
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• pp.803-805
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• 2014

The IL-16 rs4778889 T/C polymorphism is associated with cancer risk. However, the results are conflicting. We performed this meta-analysis to derive a more precise estimation of the relationship. A comprehensive literature search was performed using PubMed, Embase and Web of Science databases. Odds ratio (OR) and 95% confidence interval (CI) were used to assess the strength of association. A total of 6 studies including 1,603 cases and 2,342 controls were identified. With all studies involved, results showed no statistically significant association between IL-16 rs4778889 T/C polymorphism and cancer risk (CC vs. CT+TT: OR=0.74, 95%CI:0.55-1.02, $P_h=0.15$; CC+CT vs. TT: OR=0.89, 95%CI: 0.72-1.10, $P_h=0.03$; CC vs. TT: OR=0.73, 95%CI: 0.53-1.00, $P_h=0.08$; CT vs. TT: OR=0.91, 95%CI: 0.79-1.05, $P_h=0.08$; C vs. T: OR=0.89, 95%CI: 0.74-1.07, $P_h=0.02$). In addition, the results were not changed when studies were stratified by cancer type. However, to verify our findings, it is essential to perform more well-designed studies with larger sample sizes in the future.

• Journal of the Korean Chemical Society
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• v.17 no.5
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• pp.319-323
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• 1973

The state of carrier-free silver-111 has been studied by applying filtration method. The studies involved that the effects of pH and concentration of silver-111 in aqueous solution have been determined with membrane filters. The present studies revealed that the retainment of silver-111 on membrane filters followed Freundlish adsorption isotherm, and the adsorbed state of silver-111 was present in the form of AgOH. Also it was supposed that the formation of the non-adsorbed hydroxide of$Ag(OH)_{2}-$ may prohibit the existance of AgOH at higher pH, and it seems to be valid that the carrier-free silver-111 in aqueous solution exists in$Ag^+$state.

• Journal of the Korean Chemical Society
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• v.20 no.3
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• pp.221-228
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• 1976

The kinetics of hydrolysis of hydrazonyl bromides $(p-H,\;p-CH_3,\;p-OCH_3,\;p-Br,\;p-Cl\;&\;p-NO_2)$ have been investigated by UV spectrometry in $60{\%}$ dioxane-water at $25^{\circ}C$ and a rate equation which can be applied over wide pH range was obtained. Below pH2, the rate of hydrolysis of a series of hydrazonyl bromide is accelerated by electrondonating group (${\rho}$ = -0. 94) whereas at the pH values greater than 4, the ${\rho}$-value is 0.54. The rate equation, solvent-, substituent-and bromide ion-effect on the rate of hydrolysis are rationalized in terms of $S_N1$ and $S_N2$ mechanism: below pH 2, the hydrolysis proceed through $S_N2$, however, above pH 4, the hydrolysis is started by the attack of hydroxide ion and in the range pH 2{\sim}$4, these two reactions occur competitively.