• Proceedings of the Korean Society for Applied Microbiology Conference
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• 2005.06a
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• pp.333-333
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• 2005

• Bulletin of the Korean Chemical Society
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• v.20 no.9
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• pp.1017-1020
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• 1999

The aminolysis reactions of thiophenyl phenylacetates with benzylamines are investigated in acetonitrile at 55.0℃. Relatively large selectivity parameters, βx≒ 1.5, βz = -1.5~-1.8 and βxz = 0.92 together with the valid reactivity-selectivity principle are consistent with stepwise acyl transfer mechanism with rate limiting expulsion of the leaving group, thiophenolate anion, from the tetrahedral intermediate, T ± . The first order kinetics with respect to the benzylamine concentration and the realtively large secondary kinetic isotope effect (kH / kD = 1.2-1.7) involving deuterated benzylamine nucleophiles suggest a four center type transition state in which concurrent leaving group departure and proton transfer are involved.

• Bulletin of the Korean Chemical Society
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• v.19 no.11
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• pp.1198-1202
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• 1998

Aminolysis of aryl thiol-2-furoates and thiol-2-thiophenates with benzylainines are investigated in acetonitrile at 50.0 ℃. Relatively large selectivity parameters, ρx(βx), ρz(βx) and ρxz (> 0) together with the valid reactivity-selectivity principle are consistent with a stepwise acyl transfer mechanism with rate-limiting expulsion of the leaving group, thiophenolate anion, from the tetrahedral intermediate, T±. The first-order kinetics with respect to the benzylamine concentration and the relatively large secondary kinetic isotope effect involving deuterated benzylamine nucleophiles suggest a four-center type transition state in which concurrent leaving group departure and proton transfer are involved.

• Bulletin of the Korean Chemical Society
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• v.16 no.7
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• pp.657-661
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• 1995

Kinetic studies are carried out on the reaction of S-phenyl dithiobenzoates with benzylamines in acetonitrile at 30.0 ℃. Small magnitude of ρX (βX) as well as ρZ (βZ) obtained suggests rate-limiting nucleophilic attack of the thiocarbonyl carbon. This is supported by the unusually small magnitude of ρXY and ρYZ, albeit their signs do not agree with those expected. Moreover, the inverse secondary kinetic isotope effects (kH/kD<1.0) involving deuterated benzylamine nucleophiles are also in line with the proposed mechanism.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.143.2-144
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• 2003

Recent studies suggest that inflammatory events are implicated in a variety of ailments such as cancer and neurodegenerative diseases, and certain non-steroidal anti-inflammatory drugs have beneficial effects for the treatment or prevention of these disorders. Cyclooxygenase-2 (COX-2), the rate-limiting enzyme in the prostaglandin (PG) synthesis, is induced by various pro-inflammatory stimuli including nitric oxide (NO) and has been reported to cause and/or aggravate neuronal cell death. (omitted)

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.181.2-181.2
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• 2003

Inosine monophosphate dehydrogenase(IMPDH) catalyzes the $NAD^+$-dependent oxidation of IMP to XMP, the rate limiting step in the de novo biosynthesis of guanine nucleotide. Its critical role at the metabolic branch point in purine nucleotide biosynthesis makes it a useful target in the development of drugs for antiviral and anticancer chemotherapy and in immunosupressant area. Several compound with antiviral activity have been found to be inhibitors of IMPDH. For example, ribavirin, a competitive inhibitor of IMPDH, has broad spectrum antiviral activities against DNA and RNA viruses. (omitted)

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.184.3-185
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• 2003

Inosine 5'-monophosphate dehydrogenase (IMPDH) is a critical enzyme in the regulation of cell proliferation and differentiation. This enzyme catalyzes the $NAD^+$-dependent oxidation of IMP to XMP, the rate limiting step in de novo biosynthesis of guanine nucleotides. Therefore, the biochemical effect of IMPDH inhibition in sensitive cell types is decrease in intracellular guanine nucleotide levels, and the decrease in cellular GTP and deoxy GTP pool levels blocks DNA and RNA synthesis in rapidly proliferating tumor cells. (omitted)

• Journal of Sensor Science and Technology
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• v.33 no.3
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• pp.158-164
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• 2024

We developed a self-operated paper pump that can maintain a nearly constant flow rate of an aqueous solution along a paper strip channel in paper-based analytical devices (PADs). The quasi-stationary flow rate was controlled by increasing the crosssectional channel area (capillary force) using a fan-shaped absorption pad coupled with a paper strip channel. The flow rate is regulated by varying the fan angle of the circular absorbing pad. Furthermore, the flow rate can be increased by furnishing a hollow cavity at the center of a conventional paper strip channel. The rate was regulated by varying the length of the hollow paper channel in the flow rate range of 5.1-26.4 mm/min. As a preliminary work, a paper-pump-coupled PAD was fabricated, and its CV detection capability was evaluated for the redox reaction of Fe(CN)₆^+4/+3. The combination of a paper pump with a PAD resulted in an ideal CV curve with a higher limiting current and faster response time. These results are interpreted well by the Levich equation, which suggests that the paper pump is a very useful component in paper-based sensors.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.4
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• pp.595-599
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• 2018

Interruption system with the transformer type superconducting fault current limiter(TSFCL) is proposed in this paper. The interruption system with a TSFCL is a technology that it maximizes the interruption function of a mechanical DC circuit breaker using a transformer and a superconducting fault current limiter. By a TSFCL, the system limits the fault current till the breakable current range in the fault state. Therefore, the fault current could be cut off by a mechanical DC circuit breaker. The Interruption system with a TSFCL were designed using PSCAD/EMTDC. In addition, the Interruption system with a TSFCL was applied to the DC test circuit to analyze characteristics of a current-limiting and a interruption operation. The simulation results showed that the Interruption system with a TSFCL interrupted the fault current in a stable when a fault occurred. Also, The current-limiting rate of the Interruption system with a TSFCL was approximately 69.55%, and the interruption time was less than 8 ms.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.22 no.1
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• pp.12-24
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• 1998

The paper presents the mechanism of secondary flows and the associated total pressure losses occurring in turbine cascades with turning angle of about 127 and 77 degree. Velocity and pressure measurements are taken in seven traverse planes through the cascade passage using a prism type five hole probe. Oil-film flow visualization is also conducted on blade and endwall surfaces. The characteristics of the limiting streamlines show that the three dimensional separation is an important flow feature of endwall and blade surfaces. The larger turning results in much stronger contribution of the secondary flows to the loss developing mechanism. A large part of the endwall loss region at downstream pressure side is found to be very thin when compared to that of the cascade inlet and suction side endwall. Evolution of overall loss starts quite early within the cascade and the rate of the loss growth is much larger in the blade of large turning angle than in the blade of small turning angle.