• BMB Reports
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• v.36 no.2
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• pp.149-153
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• 2003

The dibucaine number (DN) was determined for serum cholinesterase (EC 3.1.1.8, SChE) in plasma samples. The ones with a DN of 79-82 were used, because they had the "usual" SChE variant. The enzyme was assayed colorimetrically by the reaction of 5,5'-dithiobis-[2-nitrobenzoic acid] (DTNB) with the free sulfhydryl groups of thiocholine that were produced by the enzyme reaction with butrylthiocholine (BuTch) or acetylthiocholine (AcTch) substrates, and measured at 412 nm. Dibucaine, a quaternary ammonium compound, inhibited SChE to a minimum within 2 min in a reversible manner. The inhibition was very potent. It had an $IC_{50}$ of $5.3\;{\mu}M$ with BuTch or $3.8\;{\mu}M$ with AcTch. The inhibition was competitive with respect to BuTch with a $K_i$ of $1.3\;{\mu}M$ and a linear-mixed type (competitive/noncompetitive) with respect to AcTch with inhibition constants, $K_i$ and $K_I$ of 0.66 and $2.5\;{\mu}M$, respectively. Dibucaine possesses a butoxy side chain that is similar to the butryl group of BuTch and longer by an ethylene group from AcTch. This may account for the difference in inhibition behavior. It may also suggest the existence of an additional binding site, other than the anionic binding site, and of a hydrophobic nature.

• Bulletin of the Korean Chemical Society
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• v.30 no.11
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• pp.2523-2531
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• 2009

Effects of some diacid, diamine and dinitro aromatic compounds on the structure and activity of adenosine deaminase (ADA) were investigated by UV-Vis spectrophotometry in 50 mM phosphate buffer at pH = 7.5 and 27 ${^{\circ}C}$ and molecular docking studies. The results showed that all tested ligands are showing inhibition; five ligands are uncompetitive and other two ligands are mixed of competitive and noncompetetive inhibitors with majority of competitive behavior. For the later case analysis was done based on competitive inhibition. Diacids have larger size and higher inhibition constant ($K_I$) relative to others. A logical correlation between calculated free energy of binding and experimental values was obtained for un-competitive. Experimental and calculated data showed that competitive inhibitors are distributed near the active site of enzyme and form several cluster of ranks, whereas uncompetitive inhibitors bind to the enzyme-substrate complex and distributed far from the active site. Results of structure-activity relationship showed that, larger, more hydrophobe, less spherical and more aromatic ligands have higher inhibition constants.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.11a
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• pp.27-28
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• 2021

The search for new corrosion inhibitors for different corrosive mediums is a never-ending task. In the present work, the corrosion inhibition behavior and adsorption mechanism of two novel synthetic thiazolidinedione derivatives noted MTZD and ATZD in 3.5 wt.% NaCl solution on copper were investigated. Electrochemical, scanning electron microscope (SEM), atomic force microscopy (AFM) techniques were used along with first-principles DFT calculations. At maximum inhibitor concentration i.e., 300 ppm corrosion inhibition efficiency reached maximum up to 90% and 96% for MTZD and ATZD, respectively, and thereby followed the order of ATZD > MTZD. The inhibition efficiency increased up to 24 h of immersion, and then decreased after 48h immersion. The potentiodynamic curves suggested that the inhibition action of tested compounds is a mixed type of inhibitor. The first-principles DFT calculations suggested that compounds under investigation formed covalent bonds with Cu(111) surface via reactive sites. SEM and AFM results confirmed the formation of protective barrier that prevent corrosion attack.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.467-468
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• 2000

The characterization of mixed microorganisms that have activities of protein- and lipid-degradation were studied to reduce marine pollution by fish wastes and to utilize them again as feeds or fertilizers. There was no mutual inhibition among the microorganisms. The pH and temperature for the mixed culture were found to be 7 and $32^{\circ}C$, respectively. The fish waste were started to degrade after one day, and were almost degraded after 4 days without any odor.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.11a
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• pp.32-33
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• 2021

The corrosion of the embedded steel rebars and the consequent deterioration of the reinforced concrete structure has become a challenging concern to the construction industries for the fiscal deficit. However, corrosion inhibitors are potential and being widely used for corrosion mitigation to solve such problems. This study has been focused on the mixed type of corrosion inhibitor where one component of the corrosion inhibitor is organic and another one is inorganic material. 0.1 (M) triethanolamine (TEA) and 0.01 (M) sodium hexametaphosphate (SHMP) have been mixed in distilled water to produce the mixed inhibitor. Studies of the steel rebar corrosion in chloride contaminated (3.5 wt.% NaCl) concrete pore (CCCP) solution has been conducted using different concentrations of corrosion inhibitor. Electrochemical impedance spectroscopy (EIS) method is involved to understand the corrosion behaviour of the steel rebars at different exposure durations.

• Korean Journal of Environmental Biology
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• v.26 no.3
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• pp.183-191
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• 2008

The effect of silver ion solution on the growth of Microcystis aeruginosa UTEX 2388 (cyanobacterium) and Chlorella sp. KCTC AG20136 (green alga) was investigated using separated and mixed culture in filtered natural water and BG11 medium. In separated culture, M. aeruginosa UTEX 2388 and Chlorella sp. KCTC AG20136 were found to be sensitive to 0.01 and 0.1 mg L$^{-1}$ of silver ion, respectively. Also, the silver ion concentrations for the growth inhibition of M. aeruginosa UTEX 2388 and Chlorella sp. KCTC AG20136 in the mixed culture were same in separated culture. Cyanobacteria were more sensitive to the silver ion solution than green algae. In bloom sample, the minimal inhibition concentration of silver ion solution for the low Chl-${\alpha}$ sample (110$\sim$190 ${\mu}g$ L$^{-1}$) and high Chl-${\alpha}$ sample (1,500$\sim$1,900 ${\mu}g$ L$^{-1}$) was about 0.1 and 3.0 mg L$^{-1}$, respectively. The silver ion concentration for the inhibition of algal bloom sample was affected by the algal biomass. In order to use silver ion solution for the control of algal bloom, the silver ion concentration must be determined in consideration of a minimal effect on the environment.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.6
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• pp.1177-1182
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• 1998

The antimutagenic and cancer cell growth inhibitory effects of woorimil contained herb and seaweed powders were examined. While woorimil itself showed only 40% antimutagenic effect on S. typhymurium TA98 against 4NQO(0.15 g/plate), water extracts of mountain herbs and seweeds including Comfrey, wormwood, Kale, Angelica utilis and pine leaves showed 80~90% antimutagenicity. On the other hand, these extracts along with woorimil showed 68 to 80% antimutagenic activities. Low antimutagenic activities of less than 50% were shown when these extracts were tested on TA98 against Trp P 1(0.5 g/plate), but high antimutagenic activities of 80~93.3% were shown on TA100. Water extracts of Capsella bursa pastoris and Allium grayi exhibited 60~80% of the activites in cytotoxicity tests of woorimil water extracts(0.5mg/ml) on human lung carcinoma cell. A549 showed 10% cell growth inhibitory effect. When mixed with Comfrey and Angelica utilis extracts, it showed 23~25% inhibition and other extracts showed only 12~23% inhibition. Cytotoxicity test of woorimil extracts on human liver cancer cell Hep3B revealed 20% inhibition. The additions of pine needle extracts, Angelica utilis and Comfrey showed 33%, 29% and 25% inhibition, respectively. But other extracts showed only 20% inhibition.

• Journal of Electrochemical Science and Technology
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• v.10 no.2
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• pp.231-243
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• 2019

The methanolic extracts of the leaves and stem of the plant Lepidagathis keralensis were evaluated for anticorrosion behavior against mild steel in 1M HCl. Corrosion inhibition studies were done by gravimetric method, electrochemical impedance spectroscopy and potentiodynamic polarization methods. Surface morphology of mild steel in the presence and absence of inhibitors were studied using SEM analysis. UV-Vis studies were also done to evaluate the mechanism of inhibition. Both the extracts showed good inhibition efficiency which increased with increase in concentration of the inhibitor and decreased with increase in temperature. The mechanism of inhibition was explained by adsorption which obeyed Langmuir adsorption isotherm. Thermodynamic calculations revealed a combination of both physisorption and chemisorption of the inhibitor on the surface of mild steel. The extracts behaved as mixed type inhibitors as determined by polarization studies. Quantum chemical studies on Phenoxyethene, one of the major components in the leaf extract of the plant was also carried out to support the experimental results.

• Journal of Life Science
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• v.11 no.1
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• pp.76-82
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• 2001

Fifteen species of microorganisms were isolate form the intestines of fishes, fish feed, and ferment. Eleven microorganisms except HY4, HY8, HY12, and HY13 were Gram-positive, and HY1, HY2, HY3, HY5, HY6, and HY7 produced lactic acid. The species of HY1, HY2, HY3, HY4, HY5, HY6, HY13, and HY14 showed some growth in the medium containing 1% of NaCl. Except HY6, HY7, HY8, HY12 and HY5, 10 isolates had proteolytic activity, whereas only HY13 and HY14 had lipase activity. From all the results four isolates (HY3, HY4, HY13 and HY14) were chosen for the degradation of fish wastes. There was no mutual inhibition among the microorganisms, and the optimum temperature and pH for the growth of the mixed culture were found to be 3 2$\^{C}$ and 7, respectively. Under the optimum growth conditions the maximum optical density and the maximum specific growth rate were estimated to be 2.35 and {TEX}$0.46h^{-1}${/TEX}, respectively. Major microorganisms in the mixed culture at the log-phase were HY3 and HY4, which occupied 70%. The degrading efficiency of fish waste by the mixed microorganisms was 2.3 times higher, compared to control. The total amount of free amino acids in the degraded products from fish wastes was 39g/100g protein and little odor was produced by the mixed microorganisms after 48 hours.

• Corrosion Science and Technology
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• v.8 no.1
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• pp.1-10
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• 2009

The influence of Schiff bases on the corrosion inhibition of mild steel in 1 M $H_2SO_4$ have been investigated by weight loss, gasometry, impedance and polarization techniques. The results obtained reveal that these compounds act as good inhibitors. The inhibition efficiency of Schiff bases increased with concentration and synergistically increased on addition of chromate, sulphate and halide ions. Potentiodynamic polarization measurements clearly reveal that the investigated inhibitors are of mixed type but they are more cathodic in nature. The adsorption of these compounds on mild steel surface for both the acids were found to obey Langmuir adsorption isotherm. The surface morphology was studied by SEM and UV reflectance spectra.