• Journal of the Korean Chemical Society
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• v.36 no.6
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• pp.879-888
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• 1992

Separation of the optical isomers of free amino acids by a reversed phase high performance liquid chromatography has been studied by adding a copper(II) complex of L-proline or L-proline derivatives (hydroxy-L-proline, N-benzyl-L-proline, p-xylenyl-L-proline, p-xylenyl-hydroxy-L-proline) in the mobile phase. An OPA postcolumn detection system was used for the detection of amino acids. The chromatographic properties for the free amino acids were discussed in terms of the pH, the kinds and concentration of chelate or organic modifier. The retention behaviors of the free amino acids were considerably different from, those of DNS-amino acids or DABS-amino acids. The enantioselectivity of the free amino acids was better than that of derivatized amino acids. The enantioselectivity between the optical isomers observed by use of the Cu(II)-p-xylenyl-L-proline chiral cheleate was the best among the several copper(II) chelate. A separation mechanism could be illustrated not only by the hydrophobic interaction of the diastereomer with stationary phase but also by the steric effect of the ligand exchange reaction between the free-amino acids and copper chelate.

• Korean Journal of Agricultural Science
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• v.10 no.1
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• pp.74-83
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• 1983

In order to examine the relationship of fruit abscission and ethylene evolution in 'Jojuro' and 'Imamuraaki' pear trees, the thinning chemicals, ${\beta}$-naphthalene acetic acid (NAA), O, O-dimethyl-O-(3-methyl-4 nitrophenyl) posphorothioate (MEP), 1-naphthyl N-methyl carbamate (carbaryl), and 2-chloroethyl phosphonic acid (ethephon) were applied. Concurrently the effect of calcium acetate on the control of fruit abscission were examined when calcium acetate was added to ethephon and carbaryl. 1. All the applied chemicals (MEP, NAA, carbaryl and ethephon) was effective to abscise fruits in 'Jojuro', and MEP and carbaryl in 'Imamuraaki's. 2. The application of ethephon increased the ethylene evolution but other chemicals did not increase it. 3. There were no significant differences in total sugar contents of fruits by MEP, NAA, carbaryl and ethephon treatments. 4. When the calcium acetate was added to the ethephon and carbaryl, the thinning effects were offsetted. 5. The rate of defoliation due to ethephon treatment was controlled by addition of calcium acetate at 0.1~0.25 M. It was clarified that fruit abscission induced by thinning chemicals except ethephon was not directly related to ethylene production and that degree of fruit thinning can be regulated by addition of calcium acetate to thinning chemicals.

• Journal of Wetlands Research
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• v.17 no.4
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• pp.380-390
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• 2015

In this study, the major 38 tributaries in Nakdong River were monitored for flow rate and water quality in order to understand the characteristics of the watershed and to find improvement plan. The flow rate and water quality for each target tributary were evaluated based on the monitoring data in 2013~2014 using a statistical package SPSS-22.0. In addition, the tributary grouping method was conducted using a $BOD_5$ concentration/flowrate and TP concentration/flowrate monitoring data. The average values of $BOD_5$, $COD_{Mn}$, TP and TOC concentrations in Gumicheon, Gyeonghocheon, Jincheoncheon, Gisegokcheon, Yonghacheon and Yonghocheon located at Nakdong Waegwan and Nakdong Goryung watershed were high and in the grade of III or IV (5~8 mg/L). The Pearson correlation coefficients of TOC with $BOD_5$, $COD_{Mn}$, and TP were greater (r=0.8, p<0.01) than those of the other water quality parameters (12 species). The tributaries with high values of water quality parameters ($BOD_5$ > 3.0 mg/L, TP > 0.1 mg/L) and flowrate (Q > $0.1m^3/sec$) were selected for improving water quality according to the stream grouping method. Five tributaries (Gumicheon, Gisegokcheon, Yonghacheon, Yeongsancheon, Mijeoncheon and Yonghocheon) were classified as Group I, which require polices and plans for water quality improvement.

• Journal of Life Science
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• v.25 no.4
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• pp.397-405
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• 2015

S-allylcysteine (SAC) is a water-soluble organosulfur compound abundant in the aged garlic extract and has been drawing attention as a diet-derived alternative agent not only for the effects of anti-oxidation and anti-inflammation but also for the prevention and treatment of various types of cancer. However, there is no report about the anticancer effects of SAC on cervical cancer cells. The aim of this study was to analyze the inhibitory effects of SAC on cell proliferation of cervical cancer cell line, HeLa and to examine its effects on the apoptosis and cell cycle as the cellular mechanisms of anti-proliferation. For this, we examined effects of different concentrations of SAC on cell proliferation according to treatment periods. Treatment with SAC not only induced morphological changes but also resulted in the reduction of cell viability and the inhibition of concentration- and time-dependant cell proliferation of HeLa. Furthermore, SAC also induced fragmentation of DNA in both DNA fragmentation and TUNEL assays, and induced cell cycle arrest at the G₂/M phase in cell cycle analysis. These results suggest that SAC inhibits proliferation of HeLa at least in part through the induction of apoptosis and the cell cycle arrest.

• Membrane Journal
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• v.26 no.5
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• pp.381-390
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• 2016

In this study, the natural mordenite (MOR) zeolite seeds were used for the synthesis of high purity mordenite crystals. The effect of seed concentration and crystallization time on the phase purity and surface morphology of MOR crystals has also been reported. The diffraction, elemental and scanning analysis of MOR zeolite particles obtained from 100 g hydrothermal solution batch containing 3 g natural seed, hydrothermally treated at $140^{\circ}C$ for 72 h reveal the high phase-purity of as-synthesized sample having crystals of uniform size ($1-2{\mu}m$). Moreover, high seed concentration leads to the production of mesoporous MOR particles composed of needle shape primary nano crystallites. The gases adsorption performances of as-synthesized MOR particle were carried out at $25^{\circ}C$ and 0-1 bar. Surprisingly, MOR particles show good adsorption potential for $CO_2$ (97.19 mg/g) compared to other gases. Thus it confirms that high purity MOR particles can be synthesized without using any organic template which gives an advantage of separation performance at lower price.

• Korean Journal of Microbiology
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• v.42 no.3
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• pp.223-229
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• 2006

To develop multifunctional microbial inoculant, an insluble phosphate-solubilizing bacterium with antifungal activity was isolated from plant rhizospheric soil. On the basis of its morphological, cultural and physiological characteristics and Biolog analysis, this bacterium was identified as Pseudomonas fluorescens RAF15. P. fluorescens RAF15 showed antifungal activities against phytopathogenic fungi Botrytis cinerea and Rhizoctonia solani. The optimal medium composition and cultural conditions for the solubilization of insoluble phosphate by P. fluorescens RAF15 were 1.5% of glucose, 0.005% of urea, 0.3% $MgCl_2{\cdot}6H_2\;0.01%\;of\;MgSO_4{\cdot}7H_2O\;0.01%,\;of\;CaCl_2{\cdot}2H_2O$, and 0.05% of NaCl along with initial pH 7.0 at $30^{\circ}C$. The soluble phosphate production under optimum condition was 863 mg/L after 5 days of cultivation. The solubilization of insoluble phosphates was associated with a drop in the pH of the culture medium. P. fluorescens RAF15 showed resistance against different environmental stresses like $10-35^{\circ}C$ temperature, 1-4% salt concentration and pH 2-11 range. The strain produced soluble phosphate to the culture broth with the concentrations of 971-1121 mg/L against $CaHPO_4$, 791-908 mg/L against $Ca_3(PO_4){_2}$, and 844 mg/L against hydroxyapatite, respectively. However, the strain produced soluble phosphate to the culture broth with the concentrations of 15 mg/L against $FePO_4$, and 5 mg/L against $AlPO_4$, respectively.

• Korean Journal of Environmental Agriculture
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• v.22 no.4
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• pp.294-299
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• 2003

The seeds of naturally growing Heteropappus hispidus (Thunb.) were treated by nine different doses (0, 10, 20, 40, 80, 120, 160, 200, 300, 400 Gy) of gamma rays to investigate their germination rate and to quantity the characteristics of their germinated plants as like as leaf appearance and length, the formation rate of anthocyanin color in stem 30 days after germination, the formation rate of rosette leaf and multi-shoot, the flowering and seed-bearing, and shoot length. The germination rate at least up to 120Gy was not greatly affected but was rapidly decreased at over 160Gy. It seemed that lethal dose ($LD_{50}$) of germination was 160Gy. The leaf appearance and growth was also inhibited, but the formation rate of anthocyanin color in the flower stem was enhanced up to 30% with dose. The rosette plants were observed in plants irradiated with higher than 40Gy. Multi-shoots were developed over 80Gy. For a short shoot length and bundle of thin stem, it was considered that they can be selected as the potential pot flower plants, through genetic fixation. In particular, it was suggested that the formation of anthocyanin color in flower stem, rosette and multi-shoot plants induced by the high dose of gamma rays could be utilized as the morphological markers for the mutant selection of Heteropappus hispidus (Thunb.).

• Korean Journal of Environmental Agriculture
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• v.22 no.4
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• pp.284-289
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• 2003

Titanium mesoporous materials have received increasing attention as a new photocatalyst in the field for photocatalytic degradation of organic compounds. The photocatalytic degradation of chlorothalonil by mesoporous titanium oxo-phoswhate (Ti-MCM) was investigated in aqueous suspension for comparison with $TiO_2$, (Degussa, P25) using as an effective photocatalyst of organic pollutants. Mesoporous form of titanium Phosphate has been prepared by reaction of sulfuric acid and titanium isopropoxide in the presence or n-hexadecyltrimethylammonium bromide. The XRD patterns of Ti-MCM are hexagonal phases with d-spacings of 4.1 nm. Its adsorption isotherm for chlorothalonil reached at reaction equilibrium within 60 min under dark condition with 28% degradation efficiency. The degradation ratio of chlorothalonil after 9 hours under the UV radiation condition (254 nm) exhibited 100% by Ti-MCM and 88% by $TiO_2$. However, these degradation kinetics in static state showed a slow tendency compared to that of stirred state because of a low contact between titanium matrices and chlorothalonil. Also, degradation efficiency of chlorothalonil was increased with decreasing initial concentration and with increasing pH of solution. As results of this study, it was clear that mesoporous titanium oxo-phosphate with high surface area and crystallinity could be used to photo- catalytic degradation of various organic pollutants.

• Korean Journal of Environmental Agriculture
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• v.6 no.1
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• pp.50-60
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• 1987

Sensitivity, expressed in the $96h-LC_{50}$ determined with continuous flow system, was compared for eight developmental stages of Oryzias latipes with butachlor, diazinon and fenitrothion. Significance of the laboratory determined $96h-LC_{50}$ in real field situation was evaluated for butachlor using outdoor model agrosystem. In the laboratory tests, the most sensitive stage was post-larva stage IV(7 days after hatching) with $96h-LC_{50}$ of 0.14, 1.4, and 1.6ppm for butachlor, diazinon and fenitrothion, respectively, whereas the least sensitive stage was early embryo stage(1 day after fertilization), and then the susceptibility was somewhat stable after 21days after hatching. In the model agrosystem test, the highest concentration of 0.53ppm of butachlor in water was obtained at the 2nd day after application. The stages IV and VIII showed mortality of over 50% at 96 hours after application. It is concluded that the conventional use of butachlor in the field would cause significant adverse effect on O. latipes. It is suggested that sensitivity test at the early life stages with fish is an important part of the ecotoxicological assessment of chemicals.

• Korean Journal of Environmental Agriculture
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• v.6 no.2
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• pp.22-30
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• 1987

Maize plants, grown on a German soil and a Korean soil which had treated with benzene-ring-labelled $^{14}C-Bentazon$ (5.02mg/kg) immediately before planting (T-0), took up $36.0{\sim}42.8%$ of the radioactivity present during a 21 day growing period. Plants grown on the same soils $(4.79{\sim}4.84mg/kg)$ which had been treated with Bentazon and pre-incubeted for 105days absorbed $8.2{\sim}14.2%$ (T-1) of the radioactivity. Plants grown in soils $(5.56{\sim}7.95mg/kg)$ treated with Bentazon which had been incubated for 105 days and then exhaustively extracted with distilled water and/or 0.01 M $CaCl_2$ to produce non-extractable residues (T-2) took up $1.8{\sim}2.3%$ of the radioactivity. The distribution of the absorbed radioactivity ranged from 2.7 to 9.7% in shoots and from 90.3 to 97.3% in roots. Extraction of maize roots revealed that $39.1{\sim}51.3%$ of the radioactivity was bound in T-0 and $55.7{\sim}63.1%$ was bound in T-1, This suggests hat polar metabolites and parent Bentazon might be present as conjugates.