• Applied Biological Chemistry
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• v.26 no.1
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• pp.1-7
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• 1983

The hydration of two japonica(Akibare and Milyang 15) and four indica(Milyang 30, Suweon 287, Suweon 294 and Iri 342) rice varieties was investigated in terms of mathematical rate equation. The hydration rate at temperatures of $4{\sim}32^{\circ}C$ was examined by a weighing method. The absorption of water was directly proportiponal to the square root of the hydration time(t) and was described by the diffusion equation: $1-\bar{M}=(2/\sqrt{\pi})(S/V)\;\sqrt{Dt},\;where\;\bar{M}$ is dimensionless moisture ratio, S/V is the surface-to-volume ratio and D is diffusion coefficient. The average D value was given by the Arrhenius relation: $D=D_0\;\exp(-E_a/TR)$. The activation energy was $4{\sim}5kcal/mole$. The rice samples could be classified into three groups based on hydration kinetics: Milyang 30-Suweon 287; Akibare-Milyang 15; and Suweon 294-Iri 342.

• Journal of the Korean Chemical Society
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• v.36 no.3
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• pp.405-411
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• 1992

The substitution reaction and structrue of products obtained from the reaction of Equatorial-Skew-[Co(TRDTRA)($OH_2$)] (TRDTRA = trimethylenediaminetriacetate) with $CN^-, NO^{-}_{2}$ and $NCS^-$ ions have been investigated by means of electronic absorption spectroscopy and theoretical calculation based on the Yamatera's theory. According to kinetic data, the substitution reaction order for the complexes such as $CN^-, NO^{-}_{2}$ and $NCS^-$ was the first order, respectively, and overall reaction order was second order. It has been determined that the structure of products having $CN^{-} and NO^{-}_{2}$ ions was Polar-Chair type complexes which were accompanying with isomerization and having $NCS^-$ ion was Equatorial-Skew type complex which was not accompanying with isomerization.

• BMB Reports
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• v.29 no.6
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• pp.519-524
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• 1996

Peptidylprolyl cis-trans isomerase (PPlase) catalyzes the cis-trans isomerization of prolyl peptide and facilitates the folding of cellular proteins and peptides. PPlase consists of two distinct immunophilins, each specifically binding to the immunosupressive drug cyclosporin A (CsA) or FK506, respectively. A PPlase was isolated and partially purified from porcine spleen. The molecular weight of porcine spleen PPlase was determined to be ~14,000 on the basis of SDS-PAGE. The purified enzyme was strongly inhibited by FK506, but not by CsA. The inhibition constant and the true concentration of enzyme preparations were determined by active site titration using the tight binding inhibitor FK506: $K_{i}=18.7$ nM and $E_{t}=172$ nM. The equilibrium ratio of conformer. [cis]/[trans], of prolyl peptide substrates (N-Suc-Ala-Xaa-Pro-Phe-p-NA) in anhydrous trifluoroethanol/LiCl solvent system varied from 0.24 to 0.85 depending on the nature of Xaa. Overall. in this solvent-salt system, the populations of the cis conformer of substrates in equilibrium are higher than in an aqueous solution so that the substantial error caused by high background absorption can be reduced. The reactivities of porcine spleen PPlase are shown to be highly sensitive to changes in the structure of substrates. Thus, $k_{cat}/K_m$ value for the most reactive substrate (Xaa Leu) is $4.007+10^{6}M^{1}s^{1}$ and, is 2,636 fold higher than that for the least reactive peptide substrate tested, Xaa=Glu.

• Korean Journal of Optics and Photonics
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• v.6 no.3
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• pp.201-213
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• 1995

By the use of computer simulation including collisional mixing kinetic processes of the B- and C-state in the upper laser level the output characteristics of electron-beam pumped XeF$(C\rightarrowA$ excimer laser are analyzed. We compared the results between experiments and simulations for the $XeF^*(C)$ formation that correlated the number of densities of the $XeF^*(B)$. We obtained good agreement$(28.5 mJ\pm5%)$ with comparisons between experiment and simulation and confirmed the optimal gas mixing ratio of $Xe/F_2/Ar=5.26/0.49/94.28%$ at atmospheric pressure laser medium under the condition of 70 ns [FWHM] electron-beam (800 kV, 21 kA). Also through the simulation we have investigated that the $XeF^*(C)$ formation channel, the $XeF^*(C)$ relaxation channel, and the absorption channel of bluegreen wavelength region as a function of F2 halogen donor and Xe partial pressure. ssure.

• Archives of Pharmacal Research
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• v.19 no.6
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• pp.480-485
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• 1996

Brain GABA transaminase is inactivated by preincubation with antidepressant/antipanic drug pheneizine (${\beta}$ethylphenylhydrazine) (mixing molar ratio 10:1) at pH 7.4. The reaction of enzyme with phenelzine was monitored by absorption and fluorescence spectroscopic methods. The inactive enzyme was fully reconstituted by addition of cofactor pyridoxal-5-phosphate. This result implies that the blocking of 1 mol of pyridoxal-5-phosphate per enzyme dimer is needed for inactivation of the enzyme. The time course of the reaction is significantly affected by the substrate .alpha.-ketoglutarate, which afforded complete protection against the loss of catalytic activity. The kinetic studies shows that phenelzine reacts with the cofactor of enzyme with a second-order rate constant of $2.1{\times}10^3M^{-1}s^{-1}$. It is postulated that the antidepressant/antipanic drug phenelzine is able to elevate the neurotransmitter GABA levels in central nervous system by inhibitory action on GABA degradative enzyme GABA transaminase.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.2
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• pp.66-73
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• 2017

This study was to evaluate the influential parameters such as intial Cs concentration, reaction temperature, contact time and pH variation of solution on Cs adsorption. Using the experimental data, adsorption kinetics, isotherms and thermodynamic properties were analyzed. The Cs ion adsorption of the zeolite X was effective in the range from pH 5 to 10 and reached equilibrium after 60 minutes. The adsorption kinetics and isotherms of Cs ion with the zeolite X was described well by the pseudo-second-order kinetic and Langmuir isotherm model. The maximum adsorption capacities of Cs ion calculated from Langmuir isotherm model at 293~333 K were from 303.03 mg/g to 333.33 mg/g. It was found that thermodynamic property of Cs ion absorption on the zeolite X was spontaneous and endothermic reaction. The experimental data were fitted a second-order polynomial equation by the multiple regression analysis. The values of the dependent variable calculated by this best fitted model equation were in very good agreement with the experimentally obtained values.

• Journal of fish pathology
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• v.21 no.2
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• pp.119-127
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• 2008

Oxytetracycline (OTC) has been widely used in eel culture as a therapeutic and prophylactic agent because of its broad-spectrum activity against gram-positive and -negative bacteria. The oral treatment dosage of OTC approved for the treatment of edwardsiellosis, furunculosis and vibriosis in eel is 50 mg/kg/day for 3-7 days in Korea. To determine new optimum dose of OTC in eel, the pharmacokinetics of OTC after single oral administration (100 mg/kg B.W., 200 mg/kg B.W.) in cultured eel, Anguilla japonica was examined. In oral dosage of 100 and 200 mg/kg body weight, the highest plasma concentrations of OTC were 1.19±0.42 ㎍/㎖ and 2.69±0.57 ㎍/㎖, respectively. Plasma concentrations of OTC were not detected after 720 h post-dose in all experiments. The kinetic profile of absorption, distribution and elimination of OTC in plasma wwas calculated fitting to a 1- and 2-compartment model by WinNonlin program. The following parameters were obtained for a single dosage of 100 and 200 mg/kg respectively: 1-compartment model, AUC= 82.48 and 432.68 ㎍*h/㎖, Tmax= 3.93 and 14.24 hr, Cmax= 0.94 and 2.34 ㎕/㎖; 2-compartment model, AUC= 448.73 and 530.65 ㎍*h/㎖, Tmax= 6.37 and 8.96 hr, Cmax= 0.90 and 3.21 ㎕/㎖.

• Journal of fish pathology
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• v.21 no.2
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• pp.107-117
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• 2008

The pharmacokinetic properties of oxytetracycline (OTC) were studied after dipping and oral administration to cultured olive flounder, Paralichthys olivaceus (600 g). Plasma concentrations of OTC were determined after oral dosage (50, 100 and 200 mg/kg body weight) and dipping (50, 100 and 200 ppm, 1 h) in olive flounder (average 600 g, 23±1℃). Plasma samples were taken at 3, 5, 10, 15, 24, 32, 48, 72, 120, 168 and 240 h post-dose. In oral dosage of 50, 100 and 200 mg/kg, the peak plasma concentrations of OTC, which attained at 3 h post-dose, were 0.34, 0.44 and 1.18 ㎍/㎖, respectively. In dipping of 50, 100 and 200 ppm, those of OTC which also observed at 5 h post-dose, were 0.43, 0.38 and 0.64 ㎍/㎖, respectively. Plasma concentrations of OTC were not measurable at 240 h post-dose in all experiments. The kinetic profile of absorption, distribution and elimination of OTC in plasma were analyzed fitting to a one-compartment model by WinNonlin program. The following parameters were calculated for a single dosage of 50, 100 and 200 mg/kg body weight, respectively: AUC (the area under the concentration-time curve)=31.40, 28.07 and 32.97 ㎍∙h/㎖; T1/2 (half-life)􀆫0.89, 1.12 and 0.43 h; Tmax (time for maximum concentration)= 5.25, 3.70 and 7.30 h, Cmax (maximum concentration)=0.25, 0.38 and 0.61 ㎕/㎖. Following dipping at 50, 100 and 200 ppm, these parameters were AUC􀆫15.51, 14.63 and 19.72 ㎍∙h/㎖; T1/2= 0.75, 0.41 and 0.74 h; Tmax=4.90, 7.08 and 4.68 h, Cmax=0.40, 0.32 and 0.46 ㎕/㎖.

• Korean Journal of Food Science and Technology
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• v.16 no.3
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• pp.297-302
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• 1984

Kinetics of water diffusion during soaking of two brown rice varieties, Akibare (traditional rice) and Milyang 23 (high-yielding rice), were studied. Brown rice reached at the equilibrium moisture content after 18 hours. The absorption of liquid water by brown rice grain was directly proportional to the square root of hydration time and could be described by the simplified solution of Fick's diffusion equation. The diffusion coefficient was given by the Arrhenius relation: $D\;=\;2.738{\time}10^{-1}\;exp\;(-9,300/RT)$ for Akibare and $D\;=\;4.302{\time}10^{-1}\;exp\;(-9,500/RT)$ for Milyang 23. Hydration rate calculated from hardness change followed the equation of a first order reaction. Hydration mechanism of brown rice was changed at the gelatinization temperature of rice starch.

• Advances in environmental research
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• v.9 no.2
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• pp.135-150
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• 2020

Many industries, such as textiles, chemical refineries, leather, plastics and paper, use different dyes in various process steps. At the same time, these industrial sectors are responsible for discharging contaminants that are harmful and toxic to humans and microorganisms by introducing synthetic dyes into wastewater. Of these dyes, methylene blue dye, which is classified as basic dyes, is accepted as a model dye. For this reason, methylene blue dye was selected in the study and its removal from the water was studied. In this study, two efficient biosorbents were developed from chitosan and sunflower waste, an agro-industrial waste and modified using iron nanoparticles. The biosorption efficiency was evaluated for methylene blue (MB) dye removal from aqueous solution under various parameters such as treating agent, solution pH, biosorbent dosage, contact time, initial dye concentration and temperature. We investigated the kinetic properties of dye removal from water for Chitosan-Sunflower (CS), Chitosan-Sunflower-Nanoiron (CSN). When the wavelength of MB dye was spectrophotometrically scanned, the maximum absorbance was determined as 660 nm. For the core shell biosorbents we obtained, we found that the optimum time for removal of MB from wastewater was 60 min. The pH of the best pH was determined as 5 in the studied pH. The most suitable temperature for the experiment was determined as 30℃. SEM-EDAX, TEM, XRD, and FTIR techniques were used to characterize biosorbents produced and modified in the experimental stage and to monitor the change of biosorbent after dye removal. The interactions of the paint with the surface used for removal were explained by these techniques. It was calculated that 80% of CS and 88% of CSN removed MB in optimum conditions. Also, the absorption of MB dye onto the surface was investigated by Langmiur and Frendlinch isotherms and it was determined from the results that the removal was more compatible with Langmiur isotherm.