• Applied Biological Chemistry
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• v.34 no.1
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• pp.43-48
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• 1991

New quinoline compounds were designed, synthesized, and examined with submitochondria. Most compounds showed high activity against NADH-ubiquinone oxidoreductase. Inhibition activity was mainly affected by the length of the lipophilic part, regardless of bulkiness or location of a phenyl group in the side chain. The $\beta-methyl$ group was demons)rated to be the optimal functionality on the nuclei of the quinoline derivatives so 4hat either deletion or insertion of a methylene on the group eliminated its activity.

• Korean Chemical Engineering Research
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• v.61 no.1
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• pp.52-57
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• 2023

This study is a basic research for the development of high performance flexible electrode material. To enhance its electrochemical property, CuO nanoparticles (CuO NPs) were introduced and dispersed on surface of CNT fiber through electrochemical deposition method. The CNT fiber/CuO NPs electrode was fabricated and applied to electrochemical non-enzymatic glucose sensor. Surface morphology and elemental composition of the CNT fiber/CuO NPs electrode was characterized by scanning electron microscope (SEM) with energy dispersive X-ray spectrometry (EDS). And its electrochemical characteristics were investigated by cyclic voltammetry, electrochemical impedance spectroscopy and chronoamperometry. The CNT fiber/CuO NPs electrode exhibited the good sensing performance for glucose detection such as high sensitivity, wide linear range, low detection limit and good selectivity due to synergetic effect of CNT fiber and CuO NPs. Based on the unique property of CNT fiber, CuO NPs were provide large surface area, enhanced electrocatalytic activity, efficient electron transport property. Therefore, it is expected to develop high performance flexible electrode materials using various nanomaterials.

• Korean Journal of Weed Science
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• v.18 no.2
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• pp.161-170
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• 1998

Antagonistic mode of action of fenoxaprop-P-ethyl [ethyl(R)2-4-{(6-chloro-2-benzoxazolyloxy) phenoxy}propionate] with bentazon was investigated with respect to absorption, translocation, metabolism, and change in target site response of fenoxaprop-P-ethyl using four-leaf stage of rice(Oryza sativa L.) and barnyardgrass [Echinochloa eras-galli (L.) P. Beauv.]. Shoots of rice and barnyardgrass was more sensitive to fenoxaprop-P-ethyl than the roots. More than 90% of fenoxaprop-P-ethyl was absorbed within 6 hours after treatment and 30% of the absorbed was acropetally and basipetally translocated at 24 hours after treatment. Fenoxaprop-P-ethyl was rapidly transformed to its acid form, fenoxaprop(2-[4-(6-chloro-2-benzoxazolyloxy)phenoxy]propionic acid), which was subsequently metabolized to polar conjugates. However, changes in absorption, translocation, and metabolism of fenoxaprop-P-ethyl by bentazon treatment were not found in both species. Background activity of acetyl-CoA carboxylase(ACCase) in rice and barnyardgrass was 26.5 and 23.2nmol/min/mg, respectively. Concentration required to inhibit fifty percent enzyme activity$(I_{50})$ in vitro was 6.5~7.4${\mu}M$ of fenoxaprop-P-ethyl and more than 500${\mu}M$ of bentazon. There were no significant differences in $I_{50}$ value between two treatments of fenoxaprop-P-ethyl alone and its bentazon mixture. However, bentazon reduced ACCase activity in vivo and inhibited electron transport in chloroplast thylakoid. Based on the results obtained, it is concluded that the antagonistic effect of bentazon occurs due not to direct effect on target site of fenoxaprop-P-ethyl, but to indirect involvement in reducing herbicidal activity of fenoxaprop-P-ethyl through physiological disturbances caused by bentazone at whole chloroplast level.

• Membrane Journal
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• v.25 no.5
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• pp.398-405
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• 2015

Facilitated transport is considered to be a possible solution to simultaneously improve permeability and selectivity, which is challenging in normal polymeric membranes based on solution-diffusion transport only. We investigated the effect of adding mesoporous $TiO_2$ ($m-TiO_2$) upon the separation performance of facilitated olefin transport membranes comprising poly(vinyl pyrrolidone), Ag nanoparticles, and 7,7,8,8-tetracyanoquinodimethane as the polymer matrix, olefin carrier, and electron acceptor, respectively. In particular, $m-TiO_2$ was prepared by means of a facile, mass-producible method using poly(vinyl chloride)-g-poly(oxyethylene methacrylate) graft copolymer as the template. The crystal phase of $m-TiO_2$ consisted of an anatase/rutile mixture, of crystallite size approximately 16 nm as determined by X-ray diffraction. The introduction of $m-TiO_2$ increased the membrane diffusivity, thereby increasing the mixed-gas permeance from 1.6 to 16.0 GPU ($1GPU=10^{-6}cm^3$(STP)/($s{\times}cm^2{\times}cmHg$), and slightly decreased the propylene/propane selectivity from 45 to 37. However, both the mixed-gas permeance and selectivity of the membrane containing $m-TiO_2$ rapidly decreased over time, whereas the membrane without $m-TiO_2$ had more stable long-term performance. This difference might be attributed to specific chemical interactions between $TiO_2$ and Ag nanoparticles, causing Ag to lose activity as an olefin carrier.

• Korean Journal of Microbiology
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• v.5 no.1
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• pp.15-19
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• 1967

Chlorella ellipsoidea cells were cultured in an iron, copper, zinc, manganese, molybdenum or boron-free medium. Physiological activities such as growth rate, reproduction, endogenous and glucose respiration, photosynthetic activity and biosythesis of chlorophyll of the micro-element definition cells were measured. It generally, growth rate, respiratory and photosynthetic activities, and biosynthesis of chlorophyll of the micro-element deficient cells decreased more or less, compared with those of the normal cells. The growth of the algal cells in an iron-free medium were retarded severely with the chlorosis, and the photosynthetic activity of the cells decreased remarkably even though the low content of chlorophyll in the cells owing to the iron-deficiency is considered. Therefore, it is deduced that iron takes part in the photosynthetic process itself, possibly by its participation in the photo phosphorylation coupled with electron transport. Respiratory activity of boron-deficient cells showed the most severe decrease whereas those of the molybdenum-deficient cells showed very slight decrease in spite of severe growth retardation.

• Korean Journal of Weed Science
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• v.13 no.2
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• pp.81-88
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• 1993

For searching the photosynthetic electron transport(PET) inhibitors, bio-rational screening system using thylakoid membranes extracted from wild and mutant cyanobacteria(Anacystis nidulans $R_2$) was developed. Generally, thylakoid membrane was more sensitive to the tested herbicides than the chloroplast from spinach in the Hill reaction. Higher resistant characteristics appeared in mutant D-5, Di-22 to diuron and mutant G-264 to atrazine as compared to wild type. To test the reaction of thylakoid membrane to herbicides, diuron and atrazine were applied simultaneously. Diuron and atrazine competed each other for binding with substituted amino acids, while diuron and dinoseb were non-competitive, and inhibiting activity was increased. Conclusively, bio-rational screening system using cyanobacteria was proved to be fast and efficient screening method for the development of PET inhibitors.

• Progress in Superconductivity
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• v.6 no.1
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• pp.13-18
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• 2004

High-.ate in-situ$ YBa_2$Cu$Cu_3$$O_{7-x}$ (YBCO) film growth was demonstrated by means of the electron beam co-evaporation. Even though our oxygen pressure is low, ∼$5 ${\times}$10^{-5}$ Torr, we can synthesize as-grown superconducting YBCO films at a deposition rate of around 10 nm/s. Relatively high temperatures of around 90$0^{\circ}C$ was necessary in this process so far, and it suggests that this temperature at a given oxygen activity allows a Ba-Cu-O liquid formation along with an YBCO epitaxy. Local critical current density shows a clear correlation with local resistivity. Homogeneous transport properties with a large critical current density ($4 ∼ 5 MA/\textrm{cm}^2$ at 77K, 0T) are observed in top faulted region while it is found that the bottom part carries little supercurrent with a large local resistivity. Therefore, it is possible that thickness dependence of critical current density is closely related with a topological variation of good superconducting paths and/or grains in the film bodies. The information derived from it may be useful in the characterization and optimization of superconducting films for electrical power and other applications.

• Membrane Journal
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• v.24 no.5
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• pp.367-374
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• 2014

In the present study, disc-type LSCF/GDC (20 : 80 vol%) dual-phase membranes having porous LSC/GDC (50 : 50 vol%) active layers were prepared and effect of active layers on oxygen ion transport behavior was investigated. Introduction of active layers improved drastically oxygen flux due to enhanced electron conductivity and oxygen surface exchange activity. As firing temperature of active layer increased from $900^{\circ}C$ to $1000^{\circ}C$, oxygen flux increased due to improved contact between membrane and active layer or between grains of active layer. The enhanced contact would improve oxygen ion and electron transports from active layer to membrane. Also, as thickness of active layer increased from 10 to $20{\mu}m$, oxygen flux decreased since thick active layer rather prevented oxygen molecules diffusing through the pores. And, STF infiltration improved oxygen flux due to enhanced oxygen reduction reaction rate. The experimental data announces that coating and property control of active layer is an effective method to improve oxygen flux of dual-phase oxygen transport membrane.

• Korean Journal of Environmental Agriculture
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• v.13 no.3
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• pp.373-385
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• 1994

Resistance to paraquat (1,1'-dimethyl-4,4'-bipyridilium ion) has developed in 12 species of 8 genera to which paraquat has been applied 6 to 10 times per year for 5 or more years. In recent years, tolerance to paraquat has been found in Rehmannia glutinosa (Gaertn.) Liboch. ex Fisch. & Mey. which has never been applied with any herbicides involving paraquat. In this review, we differentiate the terms, resistance and tolerance, on the basis of the paraquat-exposure history. Five hypotheses have been evaluated in several species as potential mechanisms of paraquat resistance and/or tolerance. In a species, the mode of action may be due to 1) reduced quantities of paraquat absorbed through the leaf surface, 2) detoxification of paraquat caused by the enhanced paraquat-metabolic activity, 3) rapid sequestration reducing level of paraquat at the site of action in chloroplast, 4) alteration of site of action in photosystem I resulting in interruption of electron transport to paraquat, and 5) rapid enzymatic detoxification of superoxide and other toxic forms of oxygen.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1999.10a
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• pp.28-31
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• 1999

The purpose of this study is to see the effect of microbial population and dynamics of the indigeonous microorganisms on hydrocarbon contaminated areas. The microbial structures and activities to determine the microbial capabilities of the contaminated sites are very important for the remedial action technology selection. Throughout microbial studies on different conditions by ETS(Electron Transport System) and microbial activity analysis, it was found that aeration and water contents are the most important factors in this site remediation. According to test results, Burkholderia spp. was dominant species, and acclimation is also an important factor for the accerelated biodegradation.