• Korean Journal of Agricultural Science
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• v.23 no.2
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• pp.250-260
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• 1996

Observed results of the adsorption between two competing anions for the shared sorption sites represent that the adsorption phenomena may depends on the characteristics of anion and available sorption sites in a given conditions. In binary systems, adsorption of one species can significantly influence the fate of the other anion, resulting in control of the extent of solute-adsorbate distributions throughout soil profile. And the proton-donation mechanisms by organic anions having a carboxyl as a functional group can also influence the adsorption of inorganic anions onto the hydroxylated sites of Fe and Al oxides. However, study of competitive adsorption of specifically adsorbed anions illustrates some of difficulties which arise in interpretation of reactions at oxide/aqueous solution interfaces. At least two factors prevented a simple analysis of reactions. First, at any pH value the maximum amount of adsorbate taken up at the surface depends on the identity of the anion. Second, it was necessary to postulate the sorption sites where the anion can be adsorbed. Hence, anions having non-specific adsorption characteristics are less capable for sorption sites, compared to those of specific adsorption characteristics, even though competition complies both ordinary and electrostatic interactions for sorption sites. Therefore, competition among chemical species in soil matrix can be of major significance in determining the effective mobility of any reactive anions with sorption sites.

• The Journal of the Convergence on Culture Technology
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• v.7 no.3
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• pp.285-292
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• 2021

In Sapiens it shows the reason that sapiens has conquered the earth for the invention of intersubjective reality. In Homodeus sapiens made the science revolution through the religion of humanism. The development of science showed that human free will and emotion is just made through the chemical interaction of neuron which can be manipulated and developed. Algorithm and data wlll be the sovereign which make decision in everything. Yuval Harari tells us the Homodeus appear and break down the order of equality. His anticipation proves right in competition law issues. The collusion through the algorithm makes it difficult to apply existing cartel logic. Agreement is the ground of responsibility but undertaking is not responsible in the market where sovereign algorithm decides eveything. Extreme price differentiation can appear and break down the existing market logic and competition dogma. Everything changes and it is necessary to have the flexible attitude and develop new logic.

• Korean Journal of Pharmacognosy
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• v.32 no.3 s.126
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• pp.219-225
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• 2001

The water extracts of 82 Korean medicinal herbs were examined for the binding affinity on the recombinant human muscarinic acetylcholine receptor subtype 1 $(mAChR-M_1)$ produced from the CHO (Chinese Hamster Ovary) cell line. Of those tested, the extracts of Coptidis Rhizoma, Phellodendri Cortex, Hedyotis Herba and of Terminariae Fructus were found to exhibit a significant competition with $[^3H]$ N-methyl-scopolamine for the specific binding to $mAChR-M_1$ in a dose dependent manner, respectively.

• Journal of Microbiology and Biotechnology
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• v.27 no.12
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• pp.2104-2111
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• 2017

A new series comprising phenylacetyl-homoserine lactones (HSLs), caffeoyl-HSL and feruloyl-HSL, was biologically synthesized using an artificial de novo biosynthetic pathway. We developed an Escherichia coli system containing artificial biosynthetic pathways that yield phenylacetyl-HSLs from simple carbon sources. These artificial biosynthetic pathways contained the LuxI-type synthase gene (rpaI) in addition to caffeoyl-CoA and feruloyl-CoA biosynthetic genes, respectively. Finally, the yields for caffeoyl-HSL and feruloyl-HSL were $97.1{\pm}10.3$ and $65.2{\pm}5.7mg/l$, respectively, by tyrosine-overproducing E. coli with a $\text\tiny{L}$-methionine feeding strategy. In a quorum sensing (QS) competition assay, feruloyl-HSL and p-coumaroyl-HSL antagonized the QS receptor TraR in Agrobacterium tumefaciens NT1, whereas caffeoyl-HSL did not.

• Environmental Mutagens and Carcinogens
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• v.22 no.4
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• pp.236-242
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• 2002

Using agarose-coupled methotrexate, we have successfully isolated two proteins, which have strong interactions with methotrexate. The two proteins were analyzed by Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry and identified as carbamoyl-phosphate synthetase 2 and phosphoribosylglycinamide formyltransferase, respectively. Interestingly, both of these two proteins are essential key enzymes in nucleotide biosynthetic pathways, like dihydrofolate reductase, a well-known methotrexate target. We confirmed the specificity of their interactions between methotrexate and two target proteins by the methods of competition binding assay, which were followed by western blotting using antibody against carbamoyl-phosphate synthetase 2 and phosphoribosylglycinamide formyltransferase, respectively. Moreover, we could observe that carbamoyl-phosphate synthetase 2 is overexpressed in methotrexate-resistant MOLT-3 cells comparing with control MOLT-3 cells. This result indicates that carbamoyl-phosphate synthetase 2 may be a novel target of methotrexate in cancer therapy. We propose that chemical proteomics can be a powerful technique to identify target proteins of a chemical.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.3
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• pp.471-475
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• 2006

Filling the microchannels is very important in designing micro-injection molding, microdevices, etc. In this paper, flow dynamics was studied in injection molding with microchannels. A transparent PMMA mold was designed and the flow dynamics was observed. The experiment was performed using poly (ethylene oxide) (PEO) and polyacrylamide (PA) aqueous solutions. The transignt dynamic flow and flow competition between the base plate and the microchannels were observed. The flow observation was used to explain previous filling length results in microchannels during micro-injection molding.

• Bulletin of the Korean Chemical Society
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• v.27 no.8
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• pp.1203-1205
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• 2006

During the synthesis of 4-fluorobenzaldehyde via the SNAr reaction of 4-nitrobenzaldehyde with TBAF, it was found that an equivalent amount of TBAF could oxidize benzaldehyde to benzoic acid. The reaction of 4-nitrobenzaldehyde with tetrabutylammonium fluoride (TBAF) gave 4-nitrobenzoic acid in high yield. Depending on the reaction conditions, other aromatic aldehydes produced acids with fewer amounts of alcohols. However, this type of oxidation has limited practical applications. Nevertheless, the mechanism is quite different from the Cannizzaro reaction because the amounts of the acid salt and alcohol formed were different.

• Journal of the Korean Chemical Society
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• v.14 no.2
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• pp.161-168
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• 1970

In order to obtain the more effective evidence, supporting the hypothesis which have been previously described by former report that pepsin (EC 3.4. 4.1) forms a hydrophobic bond with the nonpolar side chain of its substrate, the inhibitory effect of carboxylic acids(from formic acid to iso-butyric acid) on the activity of pepsin to the synthetic dipeptide, N-Carbobenzoxy-L-glutamyl-L-tyrosine, was discussed. The kinetic study showed that the inhibition by carboxylic acids was competitive. The Kidecreased with increasing size of the inhibitor molecule. The $-{\Delta}F^{\circ}$increased linearly with increasing number of carbon atoms in the hydrocarbon chain of the inhibitor. It was confirmed that the hydrophobic bond between more than one side chain of amino acid residues(phenylalanine) in the binding region of the active center of pepsin and the side chain of amino acid residues in the substrate was formed as the first step of its enzymic mechanism. The inhibitory effect of carboxylic acids was due to the competition of the hydrocarbon group of the carboxylic acids with the side chain of the substrate for the hydrophobic binding site(the side chain of phenylalanine) of the pepsin.

• Bulletin of the Korean Chemical Society
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• v.29 no.3
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• pp.567-570
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• 2008

A new pyrene appended diaza-18-crown-6 ether derivative 1 has been prepared and its fluoroionophoric properties toward transition metal ions were investigated. Compound 1 exhibited a high Hg2+-selectivity over other transition metal ions as well as alkali and alkaline earth metal ions in aqueous acetonitrile solution. The ratiometric analysis of the monomer and excimer emissions of pyrene successfully signals the presence of Hg2+ ions. The detection limit for Hg2+ ions was found to be 3.1 ´ 10-6 M in 50% aqueous acetonitrile solution at pH 8.1. Competition experiments also suggest that the compound could be utilized as a selective and sensitive fluorescent chemosensor for the analysis of micromolar Hg2+ ions in physiological and environmental samples.

• Bulletin of the Korean Chemical Society
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• v.29 no.2
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• pp.319-322
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• 2008

The viability of acetylene addition in each step of aromatic formation initiated by vinyl radical and acetylene also with its competition with structure rearrangement is investigated by determining optimal geometries and barrier and reaction energies using quantum mechanical methods. In principle, the addition reaction has more difficult in term of free energy and enthalpy compared to geometry arrangement. Under combustion conditions, i.e. T = 1200 K, acetylene addition is unfavorable mechanism as the barrier energy values rise much higher than that of geometry arrangement. However, in longer chain hydrocarbon case, e.g. n-CxHx+1 where x ³ 8, C-C bond rotation is rather difficult and requires high energy to form a ring structure, elongation chain is preferable.