• Korean Journal of Weed Science
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• v.16 no.1
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• pp.64-71
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• 1996

This study was conducted to determine the physiological responses of corn plants to chlorsulfuron, CHL, (2-chloro-N-(((4-methoxy-6-methyl-1,3,5- triazin-2-yl)amino)carboxyl) benzenesulfonamide) and/or imazaquin, IMA, (2-(4,5-dihydro-4-methyl-4-(1-methyl)-5-oxo-1H-imidazol-2y1)-3-quinoline carboxylic acid). CHL inhibited the plant growth within 6h after treatment, whereas IMA inhibited the growth more slowly(i.e., 36h). CHL inhibited the cell division of the root tips rapidly, however, little effect was found with IMA treatment. Neither CHL nor IMA had effect on the cell elongation of the shoots. CHL inhibited acetolactate synthase(ALS) activity of the roots within 1h after treatment. Interaction between CHL and IMA in growth inhibition was found to be additive or synergistic with simultaneous or sequential treatment of the two herbicides, respectively. In addition, interaction between CHL and IMA in ALS inhibition was found to be additive when the two herbicides were treated simultaneously.

• Journal of the Korean Ceramic Society
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• v.42 no.12 s.283
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• pp.800-807
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• 2005

Cathode material, $(Ba_{0.5}Sr_{0.5})_{0.99}Co_{0.8}Fe_{0.2}O_{3-\delta}$, for low temperature SOFC was prepared by the Glycine-Nitrate synthesis Process (GNP). Characteristics of the synthesized powders were studied with controlling the pH of a precursor solution. Highly acidic precursor solution increased a perovskite forming temperature. It is considered that Ba and Sr cannot complex by carboxylic acid group of glycine, because under highly acidic condition the caboxylic group mainly combined with H+ insead of alkaline earth cations. A lack of bond between cations and glycine resulted in selective precipitation of the elements during evaporation of the precursor solution. In case of using precursor solution with pH %2\~3$, a single perovskite phase was obtained at $1000^{\circ}C$. Polarization resistance of $(Ba_{0.5}Sr_{0.5})_{0.99}Co_{0.8}Fe_{0.2}O_{3-\delta}$ was measured by AC impedance spectroscopy from the two electrode symmetric cell. Area specific resistance of the $(Ba_{0.5}Sr_{0.5})_{0.99}Co_{0.8}Fe_{0.2}O_{3-\delta}$ air electrode at $500^{\circ}C\;and\;600^{\circ}C$ were $0.96{\Omega}{\cdot}cm^2\;and\;0.16{\Omega}{\cdot}cm^2$, respectively.

• Biomolecules & Therapeutics
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• v.4 no.3
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• pp.239-243
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• 1996

DW-116 {(1-(5-fluoro-2-pyridyl)-6-fluoro-7-(4-methyl-1-piperazinyl)-1,4-dihydro-4-oxoquinoline-3-carboxylic acid hydrochloride) is a new quinolone antibiotic with a broad antibacterial spectrum against G(+) and G(-) bacteria. DW-116 was evaluated for the appearance of micronucleus in polychromatic erythrocytes (PCEs) of mouse bone marrow cells after intraperitoneal and oral single administration. We prepared the bone marrow cells at 30hr after drug administration and they were used for measuring PCE with micronucleus. The results showed there was no statistically significant increase in the numbers of PCEs with micronucleus in all DW-116 administered groups compared with a negative control group. The results also showed that the ratio of normochromatic erythrocytes(NCEs) to PCEs of all DW-116 administered groups was not significantly different from that of a negative control group. These results suggested that DW-116 may not cause any chromosomal damage and it has no in vivo mutagenic potential under these experimental conditions.

• YAKHAK HOEJI
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• v.41 no.5
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• pp.615-621
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• 1997

Dehydropeptidase-I (DHP-I) was solubilized from porcine kidney by treatment with n-butanol and partially purified 19.25 fold by $(NH_4)_2SO_4$ precipitation, DEAE-Sepharose CL-6B ion exchange chromatography and Sephacryl S-300 HR chromatography with an overall yield of 19.16. DHP-I showed its optimal activity at pH 7.5 and 25$^{\circ}C$. Its activity was stable under neutral and alkaline conditions, but was disappeared under acidic condition. And DHP-I was heat-labile and its activity remained at 45$^{\circ}C$ for 3hrs. The enzyme was not inhibited by dicationic ions, while its activity was increased by $Co^{2+}$(1mM) and $Zn^{2+}$ (0.1mM). The enzyme was inhibited by EDTA and N-ethylmaleimide. The relative molecular mass of DHP-I was estimated to be approximately 100kDa by gel filtration chromatography. The $K_m$ value of DHP-I for glycyldehydrophenylalanine (GDHP) was 1.98mM. DWP20418 [(1R, 5S, 6S)-6-[1-(R)-Hydroxyethyl]-1-methyl-2-[(2S, 4S)-2-(piperazinylcarbonyl)-1-(R)-hydroxyethyl)pyrrolidine-4-thio]carbapen-2-em-3-carboxylic acid], compared with meropenem (MEPM), was rather easily hydrolized by DHP-I, while it was four times more resistant than imipenem (IPM) to DHP-I.

• The Korean Journal of Pesticide Science
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• v.8 no.3
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• pp.168-174
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• 2004

In a course of the process for a lead optimization of 2-imino-l,3-thiazolines 1 which show a selective in vivo antifungal activity against rice blast, new compounds 2 in which C-5 was substituted by methyl group of the lead compound were synthesized and tested for the biological activity. Bromination of $\beta$-keto ester 7 followed by the reaction with thiourea and hydrolysis gave 2-imino-5-methyl-l,3-thiazoline carboxylic acid 3. Coupling reactions of 3 with aniline derivatives afforded 17 kinds of the corresponding 2-imino-5-methyl-l,3-thiazoline carboxanilides 2. Their in vivo antifungal activity against rice blast was weaker than that of 1, indicating that the in vivo antifungal activity of 2-imino-l,3-thiazolines was affected by the substituent at C-5. These results would be an important data for the molecular design in the lead optimization process of this series.

• Journal of the Korean Applied Science and Technology
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• v.21 no.4
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• pp.345-351
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• 2004

Highly ordered pure-silica MCM-41 materials possessing well-defined morphology have been successfully prepared with surfactant used as a template. The fabrication of mesoporous silica has received considerable attention due to the need to develop more efficient materials' for catalysis, separations, and chemical sensing. The surface modified MCM-41 was used as anadsorbent for biomolecules. Silica-supported organic groups and DNA adsorption on surface modified MCM-41 were investigated by FT-IR and UV-Vis spectrometer, respectively. The use of MCM-41 as the modification of electrode surfaces were investigated electrochemical properties of metal mediators with biomolecules. The modified ITO electrodes increased peak currents for a redox process of $[Ru(bpy)_3]^{2+}$ relative to the bare electrode. The electrochemical detection of DNA by cyclic voltammetry when the current is saturated in the presence of the mediator appeared more sensitive due to a higher catalytic current on the MCM-41 supported electrodes modified by carboxylic acid functional groups. The carboxyl or amine groups on the surface of MCM-41 interact and react with the $-NH_2$ groups of guanine and backbone, respectively. Highly ordered mesoporous materials with organic groups could find applications as DNA sensors.

• YAKHAK HOEJI
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• v.40 no.3
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• pp.357-368
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• 1996

The in vitro antibacterial activity of a novel fluoroquinolone, DWP20373(1-Cyclopropyl-6-fluoro-8-methoxy-7-(2,7-diazabicyclo[3,3,0]oct-4-ene-7-yl)-1,4-dihydro-4 oxoquino line-3carboxylic acid) was compared with those of ciprofloxacin (CPFX), sparfloxacin (SPFX) and ofloxacin (OFLX). DWP20373 was more active than SPFX and OFLX but was less potent than CPFX against gram-negative bacteria. DWP20373 showed an excellent activity against L-MRSA and H-MRSA ($MlC_{90}=0.781{\sim}1.563{\mu}g/ml$).The activity of DWP20373 decreased moderately in the presence of 5mM $Mg^{2+}$. However, pH and serum had no effect on the activity of DWP20373. DWP20373 possessed a rapid bactericidal activity against gram-positive and gram-negative strains.

• Journal of the Korean Chemical Society
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• v.20 no.5
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• pp.398-405
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• 1976

A new compound, 1,2-bispyrazyl ethylene,is synthesized starting from pyrazine carboxylic acid and methyl pyrazine. The compound is characterized utilizing UV-VIS, IR, NMR and mass spectra along with elemental analysis. Spectroscopic properties are studied from UV-VIS and fluorescence spectra. From unusual salt effects on fluorescence spectra, it is believed that $(n,\;{\pi}^*)$ state has about the same energy as $({\pi},\;{\pi}^*)$ state. The compound fluoresces from $({\pi},\;{\pi}^*)$ state with the quantum yield of 0.025 at $77^{\circ}K$ compared to near unity for stilbene at the same temperature indicating the efficient intersystem crossing to triplet state, because of strong $(n,\;{\pi}^*)$ and $({\pi},\;{\pi}^*)$ mixing in the lowest excited state.

• Journal of the Korean Chemical Society
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• v.21 no.2
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• pp.108-120
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• 1977

The approximate rates and stoichiometries of the reaction of lithium borohydride, with fifty two selected organic compounds containing representative functional groups under the standard condition (tetrahydrofuran, $0^{\circ}$), were studied.Among the active hydrogen compounds,primary alcohols and compounds containing an acidic proton liberated hydrogen relatively fast, but secondary and tertiary alcohols very sluggishly. All the carbonyl compounds examined were reduced rapidly within one hour. Especially, among the ${\alpha}{\beta}$-unsaturated carbonyl compounds tested, the aldehydes consumed one hydride cleanly, however the cyclic ketones consumed more than one hydride even at $-20^{\circ}$. Carboxylic acids were reduced very slowly, showing about 60% reduction in 6 days at $25^{\circ}$, however acyl chlorides reduced immediately within 30 minutes. On the other hand, the reductions of cyclic anhydrides proceeded moderately to the hydroxy acid stage, however the further reductions were very slow. Aromatic and aliphatic esters, with exception of the relatively moderate reduction of acetate, were reduced very slowly, however lactones were reduced at a moderate rate. Epoxides reacted slowly, but amides and nitriles as well as the nitro compounds were all inert to this reagent. And cyclohexanone oxime and phenyl isocyanate were reduced very sluggishly. Last of all, all sulfur compounds studied were inert to this hydride.

• Bulletin of the Korean Chemical Society
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• v.27 no.4
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• pp.535-538
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• 2006

In our previous studies, we have observed that curcumin and momordin I isolated from Ampelopsis radix inhibit the formation of Fos-Jun-activation protein-1 (AP-1) DNA complex. We have screened more effective compounds which have a 5-membered ring framework like momordin I and have modified disaccharide or carboxylic acid portions in momordin I. We synthesized momordin I derivatives according to the published method with slight modification. Synthetic momordin I derivatives showed remarkable inhibitory activities on Fos-Jun-AP-1 DNA complex formation results in in vitro assays. The $IC_{50}$ values of momordin I derivatives were about 4.0 $\mu$M in an electrophoretic mobility shift assay (EMSA). This value is about 125 times higher than that of curcumin and about 12 times higher than that for curcumin derivative C1, and moreover about 30 times higher than that for momordin I. We found momordin I derivatives (a) and (b) are the strongest inhibitory compound for Fos-Jun-AP-1 DNA complex formation.