• Journal of Pharmaceutical Investigation
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• v.25 no.1
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• pp.9-17
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• 1995

To stabilize omeprazole(OMP), ethylenediamine(ED) complex of omeprazole(OMPED) was prepared by reaction between OMP and ED in methanol, and the complex formation was confirmed by the instrumental analysis, i.e., IR, DSC, EA, NMR, MS and XRD. The rates of decomposition of OMP and OMPED in aqueous solution and the shelf lives at standard temperature were measured by accelerated stability analysis. The results are summarized as follows; The mole ratio of OMP and ED in OMPED complex is 1:1, the energy of formation within OMPED might be combined between polar imidazole group of OMP with induced a dipole amine group in the readily polarizable ED molecule. At standard temperature the degradation rate constant of OMP in aqueous solution is $2.540{\times}10^{-2}\;hr^{-1}$ and the shelf life is 4.15 hrs, and in the case of OMPED the degradation rate constant is $7.986{\times}10^{-4}\;hr^{-1}$ and the shelf life is 131.96 hrs. So, the OMPED has about 31 times longer shelf life than OMP. The activation energy of OMP and OMPED are 5.23 and 18.55 kcal $mole^{-1}$ respectively. The stability of OMP is dependent chiefly on pH in the solutions and it decomposes readily in acidic medium by hydrogen ion catalized reaction but becomes stable beyond pH 9.0. In case of the ED-complex, OMPED is stable in neutral as well as in dilute acidic solutions even in pH 6, OMPED is very stable to light(UV), that is, the rate constant and shelf life of OMP are $k=1.0188{\times}10^{-2}\;day^{-1}$, $T_{90%}=4.5 \;days$, on the other hand, the those of OMPED are $k=7.138{\times}10^{-4}\;day^{-1}$, $T_{90%}=64.1\;days$, respectively. From the above results, it is thought that new dosage forms could be developed by using the OMPED as a potential OMP complex.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.4
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• pp.397-401
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• 2006

A laboratory study was conducted to evaluate the kinetics of oxidation of trichloroethylene(TCE) in groundwater by potassium permanganate($KMnO_4$). Consumption of permanganate by TCE and aquifer material was also evaluated to obtain an appropriate injection rate of $KMnO_4$. TCE degradation by $KMnO_4$ in the absence of aquifer material was effective with a pseudo-first order rate constant, $k_{obs}=5.24{\times}10^{-3}s^{-1}\;at\;KMnO_4=500mg/L$. TCE oxidation by $KMnO_4$ was found to be second order reaction and the rate constant, $k=0.65{\pm}0.08M^{-1}s^{-1}$. Meanwhile, aquifer materials from the field site were actively reacted with permanganate, resulting in the significant consumption of $KMnO_4$. It might be attributed to the existence of metal oxides in the aquifer materials.

• Journal of Soil and Groundwater Environment
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• v.21 no.5
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• pp.8-15
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• 2016

Bioremediation, which uses microbes to degrade most organic pollutants in soil and groundwater, can be used in solving environmental issues in various polluted sites. In this research, a wind-driven bioventing system is built to degrade about 20,000 mg/kg of high concentration diesel pollutants in soil-pollution mode. The wind-driven bioventing test was proceeded by the bioaugmentation method, and the indigenous microbes used were Bacillus cereus, Achromobacter xylosoxidans, and Pseudomonas putida. The phenomenon of two-stage diesel degradation of different rates was noted in the test. In order to interpret the results of the mode test, three microbes were used to degrade diesel pollutants of same high concentration in separated aerated batch-mixing vessels. The data derived thereof was input into the Haldane equation and calculated by non-linear regression analysis and trial-and-error methods to establish the kinetic parameters of these three microbes in bioventing diesel degradation. The results show that in the derivation of μ_m (maximum specific growth rate) in biodegradation kinetics parameters, K_s (half-saturation constant) for diesel substance affinity, and K_i (inhibition coefficient) for the adaptability of high concentration diesel degradation. The K_s is the lowest in the trend of the first stage degradation of Bacillus cereus in a high diesel concentration, whereas K_i is the highest, denoting that Bacillus cereus has the best adaptability in a high diesel concentration and is the most efficient in diesel substance affinity. All three microbes have a degradation rate of over 50% with regards to Pristane and Phytane, which are branched alkanes and the most important biological markers.

• Journal of Microbiology and Biotechnology
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• v.15 no.6
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• pp.1330-1336
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• 2005

Polyhydroxyalkanoic acid (PHA) inclusion bodies were analyzed in situ by $^{13}C$-nuclear magnetic resonance ($^{13}C$-NMR) spectroscopy. The PHA inclusion bodies studied were composed of poly(3-hydroxybutyrate) or poly(3hydroxybutyrate-co-4-hydroxybutyrate), which was accumulated in Hydrogenophaga pseudoflava, and medium-chain-length PHA (MCL-PHA), which was accumulated in Pseudomonas fluorescens BM07 from octanoic acid or 11-phenoxyundecanoic acid (11-POU). The quantification of the $^{13}C$-NMR signals was conducted against a standard compound, sodium 2,2-dimethyl-2-silapentane-5-sulfonate (DSS). The chemical shift values for the in vivo NMR spectral peaks agreed well with those for the corresponding purified PHA polymers. The intracellular degradation of the PHA inclusions by intracellular PHA depolymerase(s) was monitored by in vivo NMR spectroscopy and analyzed in terms of first-order reaction kinetics. The H. pseudoflava cells were washed for the degradation experiment, transferred to a degradation medium without a carbon source, but containing 1.0 g/l ammonium sulfate, and cultivated at $35^{\circ}C$ for 72 h. The in vivo NMR spectra were obtained at $70^{\circ}C$ for the short-chain-length PHA cells whereas the spectra for the aliphatic and aromatic MCL-PHA cells were obtained at $50^{\circ}C\;and\;80^{\circ}C$, respectively. For the H. pseudoflava cells, the in vivo NMR kinetics analysis of the PHA degradation resulted in a first-order degradation rate constant of 0.075/h ($r^{2}$=0.94) for the initial 24 h of degradation, which was close to the 0.050/h determined when using a gas chromatographic analysis of chloroform extracts of sulfuric acid/methanol reaction mixtures of dried whole cells. Accordingly, it is suggested that in vivo $^{13}C$-NMR spectroscopy is an important tool for studying intracellular PHA degradation in terms of kinetics.

• Journal of Environmental Health Sciences
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• v.32 no.6
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• pp.578-584
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• 2006

This research was conducted to estimate the effect of C/N ratio control on composting of TNT (2,4,6 trinitrotoluene)-contaminated soil. Glucose or acetone was selected to control C/N ratio of the contaminated soil. The C/N ratios of the controlled experiment and no controlled one were 26.0 and 6.6, respectively. During 45days, the degradation efficiency (96.0 or 91.8%) of acetone or glucose C/N ratio controlled soil was higher than that (78.4%) of no C/N ratio controlled case. The first order degradation rate constant of glucose or acetone C/N ratio control was 0.0641 or 0.0820/day. This constant was over twice 0.0356/day of no C/N ratio control. The C/N ratio control with glucose or acetone also showed a rather high $CO_2$ evolution than that without C/N ratio control. It was proven that C/N ratio control for composting of TNT-contaminated soil improved the treatment efficiency.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2003.10a
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• pp.116-121
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• 2003

In this study, the thermal degradation process has been investigated at various reaction temperature$(350{\sim}400^{\circ}C)$ and times$(30{\sim}120\;min)$ in order to recycle waste plastic films as solid state wax. Waste plastic films were easily melted by adding a small amount of waxes. The effects of wax addition and nitrogen flow rate on their thermal degradation properties were investigated. FT-IR, GPC and viscometer were used to analyze properties of the solid wax including the structure, molicular weight distribution and melt viscosity. The average molecular weight of solid wax was decreased with increasing the reaction time, temperature and amount of wax added, Also, the viscosity of solid wax decreased with increasing the stirring speed at a constant reaction temperature and time, and its viscosity got close to zero above $390^{\circ}C$.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.9 no.1
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• pp.45-48
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• 1984

A serious degradation of blocking of the detection performance in a cell aeraging-logarithmic detector/constant false alarm rate(CA-LOG/CFAR) is known to be caused by the presence of a large interfering noise in the set of sample mean. A technique consisting of the logarithmic circuit and inverter has been proposed to alleviate this problem, by modifying the conventional CA-LOG/CFAR receiver. The detection performance of the proposed technique is linearly improbed over the normal output level and the blocking characteristics of the CA-LOG/CFAR can be changed to finite output level.

• Journal of Pharmaceutical Investigation
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• v.18 no.4
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• pp.203-208
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• 1988

The stability and solubility of piroxicam in propylene glycol (PG), polyethylene glycol (PEC), and PG-water cosolvents have been studied by using high performance liquid chromatography. The degradation rate followed an apparent first-order kinetic and the reaction rate constants at 70, 80, and $90^{circ}C$ were determined. From these rate constants, the activation energy and the rate constant of piroxicam at $25^{circ}C$ in pure PG calculated by Arrhenius equation were 23.34 kcal/mole and $7.0\;{\times}\;10^{-4}\;day^{-1}$, respectively. Both of PG and PEG increased the solubility of the drug, but PEG was more effective.

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.403-408
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• 2003

A newly isolated Rhodopseudomonas palustris P4 could decolorize various synthetic dyes containing different chromogenic groups such as azo linkage (Crocein Orange G, New Coccine, Chromotrope FB, Congo Red, Remazol Black B), anthraquinone Reactive blue 2, or indigo Indigo Carmine. Among them, the degradation rate of Black B was studied in detial. Degradation of Black B followed the Arrhenius equation in 25 - $40^{\circ}C$ with an activation energy of 7.79 kcal/mol. Optimum pH was 8. Glucose in the range of 5 - 50g/l did not affect the Black B decolorization. When Black B increased from 25 mg/l to 2000 mg/l, decolorization activity increased almost linearly but the extent of decolorization was constant at about 86% irrespective of dye concentration. Analyses by HPLC revealed that the Black B molecules were partially degraded and some chromogenic intermediates were produced. These results indicate that Rps. palustris P4 has an outstanding capability to degrade various dyes.

• Journal of Pharmaceutical Investigation
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• v.2 no.2
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• pp.5-17
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• 1972

It was reported that cyclodextrin has a distinctive ability to form inclusion compound with a wide variety of compounds. The authors studied the stability of acetylsalicylic acid in cyclodextrin solution. From the results of this experiment, the decomposition of Aspirin in cyclodextrin solution was progressed according to the pseudofirt order reaction and its degradation rate constant was decreased and the thermodynamic activation energy of the degradation of aspirin was accetrated with the increase of cyclodextrin Conclusively, it was considered that cyclodextrin increased the stability of aspirin in aqueous solution by its inclusion compound formation.