• Bulletin of the Korean Chemical Society
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• v.15 no.11
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• pp.957-961
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• 1994

Epoxidation of olefins catalyzed by iron-tetraarylporphyrins were studied to see the shape selectivity in the competing reaction between cis-and trans- or internal and external olefins. Cis-olefins were more reactive than trans-olefins in the competing reaction between cis-and trans-olefins. Interestingly, in the epoxidation of $cis-{\beta}-methystyrene$ by ${\alpha}{\beta}{\alpha}{\beta}$ atropisomer of Fe(III)TNPPPCl and iodosylbenzene, 27% of total product was phenylacetone. The unusually large amount of phenylacetone may be produced by hydride rearrangement of carbocationic intermediate. Regioselectivity of the reaction was also studied by using the most sterically hindered Fe(III)TTPPPCl. In the epoxidation of limonene with Fe(III)TTPPPCl, the disubstituted double bond was more reactive than trisubstituted double bond. This is in contrast to the results obtained with other iron-tetraarylporphyrins. Similar trend was also observed in the competing reaction between mono-and di-substituted olefins.

• Bulletin of the Korean Chemical Society
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• v.15 no.9
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• pp.743-748
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• 1994

Photochemical reactions of saccharin with tertiary amines were explored. Saccharin was found to undergo an acid-base reaction with N-trimethylsilylmethyl-N,N-diethyl amine to form N-trimethylsilylmethyl-N,N-diethyl ammonium saccharin salt which is in equilibrium with free saccharin and N-trimethylsilylmethyl-N,N-diethyl amine insolution. Photoreaction of N-trimethylsilylmethyl-N,N-diethyl ammonium saccharin in $CH_3OH\;or\;CH_3CN$ results in the generation of desilylmethylated product, N,N-diethyl ammonium saccharin mainly along with benzamide. Photoreaction of N-methylsaccharin with N-trimethylsilylmethyl-N,N-diethyl amine in $CH_3OH$ leads to the production of o-(N-methylcarbamoyl)-N-ethylbenzenesulfonamid e as the major product along with N-methylbenzamide as the minor product. On the other hand, photoreaction of N,N,N-triethyl ammonium saccharin, generated from saccharin and triethylamine, produces N-methylbenzamide as the exclusive product. These photoreactions are quenched by oxygen indicating that triplets of saccharin and N-methylsaccharin are the reactive excited states. Based on the consideration of the redox potentials of saccharin and N-trimethylsilylmethyl-N,N-diethyl amine, and the nature of photoproducts, pathways involving initial triplet state single electron transfer are proposed for photoreactions of the saccharins with the ${\alpha}$-silylamine.

• Journal of the Korea Society of Computer and Information
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• v.4 no.2
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• pp.147-154
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• 1999

Research and Development (R&D) departments concentrate their efforts on one of two key types of research: fundamental research to discover new technology, and product development research to determine ways to use new technology or to improve upon already existing technology. Of these two types of research, the first, fundamental research, does not guarantee that successful products will develop. This type of research generally requires the investment of large sums of money without the surety of financial gain. It can, however, greatly enhance a company's image and profit potential if it can then develop a successful product from the fundamental research their scientists and engineers have done. Also, through this type of research, companies can register patents which can result in income from the sale or license of the patented technology or process to other companies. Companies place themselves at financial risk when they delve into fundamental research. For that reason, most companies concentrate their research funds and efforts on the second type of research, product development. For a product to be considered successful the company must realize some sort of benefit such as profit, increased marketshare, market recognition, or any other company-defined benefits. Both types of research require a company's consistent financial investment and planning. As the world market becomes more competitive, only those companies that can produce a product with good quality, competitive pricing, and in a timely manner will thrive. This thesis focuses on issues for developing a successful product through examining a product life cycle, a product portfolio matrix, and reactive and proactive marketing strategies.

• Parasites, Hosts and Diseases
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• v.31 no.3
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• pp.259-268
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• 1993

When activity of peroxidase in auld Pnrqfonimn westermqni was monitored using o-dianisidine and $H_2O_2$ as substrates, its specific activity was 1.5 times higher In excretory-secretory product (ESP) than in crude extract. The one was purified by two purification steps of Sephacryl S-300 Superfine gel permeation and DEAE-Trisacryl M anion exchange chromatographies. Its activity increased 16.9 fold with 32.3% recovery. The enzyme was inhibited totally by 1 millimoles of dithiothreitol (DTT), 2-mercaptoethanol and azide. Molecular mass was 16 kDa in reducing SDS-polyacrylamide gel electrophoresis (PAGE) or 19 kDa in TSK-Blue gel filtration high performance liquid chromatography (HPLC). respectively. Special staining for peroxidase by diaminobenzidine on SDS-PAGE confirmed the activity. The peroxidase was less reactive to a paragonimiasis serum when observed by SDS-PAGE/immunoblot. In addition, specific activities of superoxide dismutase (SOD) and catalase were also identified in the ESP. High activities of these antioxidant enzymes in ESP indicate that they are parts of defense mechanisms against reactive oxygen intermediates from host.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1215-1220
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• 2004

Reactive distillation (RD) is a combination process where both separation and reaction are considered simultaneously in a single vessel. This kind of combination to enhance the overall performance is not a new attempt in the chemical engineering areas. The recovery of ammonia in the classic Solvay process for soda ash of the 1860s may be cited as probably the first commercial application of RD. The RD system has been used for a long time as a useful process and recently the importance of the RD is enlarged more and more. In addition to that, the application fields of RD are diversely diverged. To make the most of the characteristic of RD system, we must decide the best operating condition under which the process shows the most effective productivity and should decide the best control algorithm which satisfies an optimal operating condition. Phosgene which is a highly reactive chemical is used for the production of isocyanates and polycarbonates. Because it has high reactivity and toxicity, its utilization is increasingly burdened by growing safety measures to be adopted during its production. Dimethyl Carbonate (DMC) was proposed as a substitute of phosgene because it is non-toxic and environmentally benign chemical. In this study, RD is used for DMC production process and the transesterification is performed inside of column to produce DMC. In transesterification, the methanol and ethylene carbonate (EC) are used as the reactants. This process use homogeneous catalyst and the azeotrope exists between the reactant and product. Owing to azeotrope, we should use two distillation columns. For this DMC production process, we can suggest two configurations. One is EC excess process and the other is methanol excess process. From the comparison of steady state simulation results where the Naphtali-Sandholm algorithm is used, it showed the better performance to use the methanol excess process configuration than EC excess process. Then, the dynamic simulation was performed to be based on the steady state simulation results and the optimal control system was designed. In addition to that, the optimal operating condition was suggested from previous results.

• Applied Biological Chemistry
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• v.39 no.3
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• pp.227-234
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• 1996

4-Methyl-2,6,7-trioxa-1-phosphabicyclo [2,2,2] octane 1-sulfide (BPS), 4-Methyl-2,6,7-trioxa-1-phosphabicyclo[2,2,2] octane 1-oxide (BPO) and related monocyclic methylphosphates were prepared and the oxidation of BPS with MCPBA in chlorofrom or methanol was carried out to investigate the formation of reactive intermediates and reaction mechanism. BPO was the only product in chloroform while in methanol isomeric monocyclic methylphosphates were formed through opening of bicylic structure with subsequent phosphorylation of methanol by reactive intermediate formed in reaction. Formation of little amount of BPO was also observed. The structure of phosphorylating intermediate was probed with various spectroscopic methods and monocyclic methyl sulfenyl ester was suggested as a possible structure.

• Journal of Microbiology and Biotechnology
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• v.31 no.7
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• pp.967-977
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• 2021

A total of 37 bacterial isolates were obtained from dye-contaminated soil samples at a textile processing factory in Nakhon Ratchasima Province, Thailand, and the potential of the isolates to decolorize and biotransform azo dye Reactive Red 141 (RR141) was investigated. The most potent bacterium was identified as Paenibacillus terrigena KKW2-005, which showed the ability to decolorize 96.45% of RR141 (50 mg/l) within 20 h under static conditions at pH 8.0 and a broad temperature range of 30-40℃. The biotransformation products were analyzed by using UV-Vis spectrophotometry and Fourier-transform infrared spectroscopy. Gas chromatography-mass spectroscopy analysis revealed four metabolites generated from the reductive biodegradation, namely sodium 3-diazenylnaphthalene-1,5-disulfonate (I), sodium naphthalene-2-sufonate (II), 4-chloro-1,3,5-triazin-2-amine (III) and N¹-(1,3,5-triazin-2-yl) benzene-1,4-diamine (IV). Decolorization intermediates reduced phytotoxicity as compared with the untreated dye. However, they had phytotoxicity when compared with control, probably due to naphthalene and triazine derivatives. Moreover, genotoxicity testing by high annealing temperature-random amplified polymorphic DNA technique exhibited different DNA polymorphism bands in seedlings exposed to the metabolites. They compared to the bands found in seedlings subjected to the untreated dye or distilled water. The data from this study provide evidence that the biodegradation of Reactive Red 141 by P. terrigena KKW2-005 was genotoxic to the DNA seedlings.

• Journal of Life Science
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• v.25 no.6
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• pp.656-662
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• 2015

Natural products and natural product structures play a general and highly significant role in drug discovery and development process because it has various merits and potentials for new drug source that have extensive clinical experience, development time contraction, excellent stability and safety. In several neurological disorders, neuronal death and excessive activation of microglia (neuro-inflammation) are observed. A number of drug discovery-related neuronal cell death and neuro-inflammation was studied from natural products, respectively. However, until now, it has not been possible to study dual-protection molecules recorded in the Natural Product library. In the present study, using the natural product-derived library of the Institute for Korea Traditional Medical Industry, we investigated dual-protective molecules against glutamate (a classical excitatory neurotransmitter)-induced oxidative stress mediated neuronal cell death and LPS-induced excessive activated microglial cells (immune cells of the brain). Chrysophanol, extracted from Rheum palmatum, had dual-protective effects against both glutamate-induced neuronal cell death and LPS-induced NO production, triggering proinflammatory cytokines and microglia activation and resulting in neuroinflammation. Flow-cytometry analysis revealed that chrysophanol had a scavenger effect, scavenging glutamate- and LPS-induced reactive oxygen species (ROS) produced by neuronal and microglial cells, respectively. Based on the present study, chrysophanol may have an important protective role against neuronal cell death and neuroinflammation in the brain. The results may be helpful for studying drug development candidates for treating central nervous system disorders.

• Journal of the Korean Ceramic Society
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• v.35 no.9
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• pp.899-904
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• 1998

Interface reaction between LSMC and YSZ is discussed with chemical composition of LSMC. The reac-tivity between LSMC and YSZ increased with increasing Co amount and A-site deficient perovskite is very effective on reducing reactivity. The (La0.8Sr0.2)xMn0.8Co0.2O3 (X=0.9-1) composition is not reactive with YSZ in experimental range. The electrode reaction reaction resistance increases due to reaction product.

• Natural Product Sciences
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• v.9 no.4
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• pp.223-225
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• 2003

Ocimum sanctum, the Indian holy basil has significant abilities to scavenge highly reactive free radicals. Shade dried leaf powder of plant has extracted with water and alcohol, fractionated with different solvents. Both extracts and their fractions were found to be good scavengers of Superoxide and hydrogen peroxide. Free radical scavenging action of these compared with ascorbic acid, a known antioxidant.