• Journal of Plant Biology
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• v.19 no.4
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• pp.95-99
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• 1976

This work deals with different extraction media and reaction mixtures on photosystem II activity of Spinach chloroplasts. The photoreduction rate of ferricyanide and DPIP by intact chloroplasts which extracted with four kinds of extraction media; S-Tris-N pH 7.2, 8.0, S-Tricine-N pH 7.2, 8.0, was measured in five kinds of reaction mixtures; S-Tris-N pH 7.2, 8.0, S-Tricine-N pH 7.2, 8.0, 0.05 M-Tris pH 7.2. The extraction medium which shows the highest photoreduction rate was S-Tris-N at pH 7.2 and S-Tricine-N at pH 8.0. As to the reaciton mixture, S-Tricine-N pH 8.0 showed the highest rate. On the complex effects of extraction media and reaction mixtures, the highest photordeuction rate of Hill oxidant by intact chloroplasts was obtained by S-Tris-N pH 7.2 extraction medium and S-Tricine-N pH 8.0 reaction mixture. The second highest activity was obtained by S-Tricine-N pH 8.0 extraction medium and reaction mixture.

• The Korean Journal of Zoology
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• v.39 no.2
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• pp.182-189
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• 1996

It has been known that spermatozoa should obtain their fertilizing ability through capacitation and acrosome reaction, and that in these processes of fertilization, Ca2+ platys an important role for their conjugation. Therefore the present study has been designed in order to clarify the effect of fluctuation of the media Ca2+ level and the intracellular concentration of the spermatozoa on the acrosomes. During the incubation of spermatozoa, a considerable fluctuation in the media Ca2+ level has been observed after the BSA administration and the media concentration of Ca2+. It is deduced that these fluctuation rates may have an effect on the acrosome reaction. The fluctuation of K+ flux has been observed in accordance with the incubation period over time, and it's concentration seems to be closely related with the acrosomal reaction. The respiratory exchange rate (RERI of the spermatozoa is kept more regular in the BSA and Cacl2 administration groups than the non-administration group. Based on the experimental findings, it is possible to deduce a hypothesis from these findings that physiological activities of the acrosome reaction are not functionally related to the media Ca2+ level and the intracellular influx of Ca2+ concentration, although Ca2+ platys an important role as a stimulating factor in the acrosome reaction.

• Bulletin of the Korean Chemical Society
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• v.25 no.7
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• pp.1009-1011
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• 2004

In the present work a very simple, sensitive and selective spectrophotometric method for the determination of nitrite in micellar media is described. The method is based on the color reaction of nitrite with p-nitroaniline in the presence of diphenylamine in acid media. In order to remove the extraction step, Triton X-100, a non-ionic surfactant was used as micellar media. The optimum reaction conditions such as acid concentration, reagents concentration and effect of time have been studied and the analytical characteristics of the method such as limit of detection, linear range and molar absorptivity have been obtained. The interference of some anions and cations was also tested. The method was applied to the determination of nitrite in real samples.

• Bulletin of the Korean Chemical Society
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• v.27 no.3
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• pp.345-354
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• 2006

Ionic liquids are alternative reaction media of increasing interest and are regarded as an eco-friendly alternatives, of potential use in place of the volatile organic solvents typically used in current chemical processing methods. They are emerging as the smart and excellent solvents, which are made of positive and negative ions that they are liquids near room temperature. The nucleophilic substitution reaction is one of the important method for inserting functional groups into a carbon skeleton. Many nucleophilic substitution reactions have been found with enhanced reactivity and selectivity in ionic liquid. In this review, some recent interesting results of nucleophilic substitution reactions such as hydroxylations, ether cleavages, carbon-X (X= carbon, oxygen, nitrogen, fluorine) bond forming reactions, and ring opening of epoxides in ionic liquids are discussed.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.11 no.1
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• pp.32-55
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• 1975

The ammonium salt of N-Nitrosophenylhydroxiamine, namely Cupferron, is a well-known analytical reagent which precipitates a great number of metal ions in acid medium. Various structures of electrode reduction for N-Nitrosophenylhydroxiamine have been suggested in acid and alkaline media by many researchers, but not in neutral medium. So the mechanism of electrode reaction of Cupferron was investigated by both chronopotentiometric and polarographic methods. It was estimated that the reduction of Cupferron occurs in a three-step mechanism through which a chemical step is interposed between two charge transfer, the ECE (charge transfer-chemical reaction-charge transfer) mechanism, over a range of neutral and alkaline media. The chemical reaction of the process was assumed to be acid-base catalyzed from the fact that kapp (over all rate constant) of chemical reaction is pH dependent.

• Analytical Science and Technology
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• v.30 no.3
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• pp.138-145
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• 2017

Microwave-assisted organic synthesis has gained a remarkable interest over the past years because of its advantages - (i) rapid energy transfer and superheating, (ii) higher yield and rapid reaction, (iii) cleaner reactions. Ionic liquids are well known for their unique properties such as negligible vapor pressure and high thermal stability. With these properties, ionic liquids have gained increasing attention as green, multi-use reaction media. Recently, ionic liquids have been applied as reaction media for biocatalysis. Lipase-catalyzed reactions in ionic liquids provide high activity and yield compared to conventional organic solvents or solvent free system. Since polar molecules are generally good absorbent to microwave radiation, ionic liquids were investigated as reaction media to improve activity and productivity. In this study, therefore, the effect of microwave irradiation in ionic liquids was investigated on lipase catalyzed reactions such as benzyl acetate synthesis and caffeic acid phenethyl ester synthesis. Comparing to conventional heating, microwave heating showed almost the same final conversion but increased initial reaction rate (3.03 mM/min) compared to 2.11 mM/min in conventional heating at $50^{\circ}C$.

• Applied Chemistry for Engineering
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• v.16 no.5
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• pp.595-602
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• 2005

Ionic liquids (ILs) are the ionic salts pertaining to liquid-state at lower temperature than $100^{\circ}C$. ILs have attracted attention as new media because of their peculiar chemical, physical or electrical properties such as low volatility, nonflammability, liquid-phase stability at high temperature, high ability in solvating organic, inorganic or polymeric materials, and high ionic conductivity. Since the properties can be modified by assembling the pair using various anions and cations, ILs are often called designer solvents. In addition, ILs have been expected as new green media to replace the volatile organic solvents, which have been widely used in chemical, energy, material, and electronic industries, as well as to enhance the reaction activity and selectivity. In this review paper, the structures, properties, applications, and technology trend of ILS are introduced.

• Transactions of the Korean hydrogen and new energy society
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• v.15 no.4
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• pp.274-282
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• 2004

This study focused on the development of high performance catalyst for autothermal reforming (ATR) of gasoline to produce hydrogen. The ATR was carried out over MgO/Al2O3 supported metal catalysts prepared under various experimental conditions. The catalysts before and after reaction were characterized by N2-physisorption, CO-chemisorption, SEM and XRD. The performance of supported multi-metal catalysts were better than that of supported mono-metal catalysts. Especially, it was observed that the conversion of iso-octane over prepared Ni/Fe/MgO/Al2O3 catalyst was 99.9 % comparable with commercial catalyst (ICI) and the selectivity of hydrogen over the prepared catalyst was 65% higher than ICI catalyst. Furthermore, it was identified that the sulfur tolerance of prepared catalyst was much better than ICI catalyst based on the ATR reaction of iso-octane containing sulfur of 100 ppm. Therefore, Ni/Fe/MgO/Al2O3 catalyst can be applied for a fuel reformer, hydrogen station and on-board reformer in furl cell powered vehicles.

• Asian Journal for Public Opinion Research
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• v.10 no.1
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• pp.51-73
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• 2022

This study investigated 3.50 million Facebook reactions collected from 9,429 Bangladeshi news items about rape shared on social media from 2016 to 2021. The primary aim of this study was to understand users' different reaction patterns based on the five major Facebook reactions (i.e., love, haha, wow, sad, and angry). Based on the theories of emotion, we quantitatively answer one research question: How do social media users react to rape with the five major Facebook reactions? The results suggest that users are more likely to express disdain toward rape and sympathy toward the victims using Facebook reactions by using the angry button, along with the sad button. In rape news, both reactions are consistent and maintain a strong positive correlation, meaning they increase and decrease together. Although many users tend to mock and laugh at rape incidents and the victims, trend lines suggest that such expressions may not be consistent with time. Despite contextual relevance, we presume that in socially and morally unacceptable events like rape and war, the valences of reactions alter to some extent: angry and sad usually become positive, while love, wow, and haha become negative. Some strengths and limitations of the study are discussed as well.

• Journal of the Korean Chemical Society
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• v.29 no.6
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• pp.623-628
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• 1985

Rate constants for complexing with thiocyanate after ring opening of molybdenum-oxalate in acid media were obtained spectrophotometrically at 460nm. The acid-assisted dissociation of molybdenum-oxalate and the reaction of thiocyanate with oxalatooxomolybdenum (V) complex in acid media were investigated with thiocyanate and hydrogen ion concentration. The kinetic data indicate that molybdenum-oxalate is protonated to a limited extent in acid media and the protonated complex is responsible for an increase in rate for the reaction of thiocyanate with oxalatooxomolybdenum (V) complex. Replacement of an oxalate ligand in acid media has been interpreted in terms of dissociative mechanism involving bond-breaking of the oxygen trans to the yl oxygen.