• Bulletin of the Korean Chemical Society
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• v.7 no.3
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• pp.186-190
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• 1986

Effects of substituents in the nucleophile(X), the substrate(Y) and the leaving group(Z) on the structure of $S_N2$ transition states have been analyzed by considering effects of four components, electrostatic($E_{es}$), exchange repulsion ($E_{ex}$), polarization($E)_{pl}$) and charge transfer($E_{ct}$) terms, of interaction between the reactants on the degree of bond making and bond breaking. Prediction of net effects of all substituents(X, Y and Z) on the degree of bond making were found to be clearcut whereas the effect of an electron withdrawing group on the substrate (Y = EWG) on the degree of bond breaking was complex; the substituent(Y = EWG) is normally carbon-leaving group($C^{\ast}$-L) bond tightening($E_{pl}$ dominance) but becomes $C^{\ast}$-L bond loosening when the bond is strongly antibonding ($E_{ct}$ dominance). Our model calculations on the reaction of $CH_2XNH_2$ with $YCH_2COOCH_2Z$ using energy decomposition scheme have confirmed that predictions based on our analysis are correct.

• KSBB Journal
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• v.6 no.3
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• pp.309-319
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• 1991

A continuous stirred tank membrane reactor(CSTMR ) was developed and optimized for the production of cod skin gelatin hydrolyzates using endo-protease Alcalase. A experimental design methodology was used to optimize the four performance variables: enzyme concentration, substrate concentration, permeate flux and reactor volume. All four variables studied had an effect on substrate conversion, with enzyme and substrate concentrations being predominant. Conversion increased with the increase in enzyme concentration, with the decrease in substrate concentration, at high volumes and low flux. A strong interaction was observed between enzyme and substrate concentrations and smaller interactions between enzyme and flux and substrate and flux. The optimum operating conditions for the CSTMR process for an initial substrate concentration for 10% were $50^{\circ}C$, pH 8, flux 7.3ml/min, residence time 82 min, and Alcalase to substrate ratio 0.02(w/w). A gradual decay in reactor activity during 8 hrs was 2.1% conversion/hr. Enzyme leakage through the 10, 000 MWCO membrane was 16% at $50^{\circ}C$ and 12% at $35^{\circ}C$, 6hrs. However, there was no apparent correlation between enayme leakage and substrate conversion. The Km value for the CSTMR was 20 times higher than the batch reactor. The productivity(expressed as mg product/mg enzyme) of the CSTMR was more than six fold higher than the batch at $50^{\circ}C$. The hydrolyzate was non-bitter.

• Korean Journal of Biological Psychiatry
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• v.4 no.2
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• pp.162-167
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• 1997

There is no doubt that dopamine plays a critical role in the etiopathogenesis of schizophrenia. However, there appeared some limitations in explaining the complex phenomena of schizophrenia. Recent research data suggest that dysfunction in serotonergic system may be involved. Before the dopamine hypothesis of schizophrenia became established, the interest in serotonin(5-hydroxytryptamine, 5-HT) as an etiological substrate of this illness occurred. Recently the importance and extent of 5-HT's involvement in the pathophysiology and mechanism of action of antipsychotic drug is actively investigated. In recent years, therapeutic success of clozapine and risperidones has increased attention on the interaction between the 5-HT and dopamine systems in schizophrenia. This led to the concept of serotonin-dopamine antagonist for antipsychotics. The authors review the evidence for the role of 5- HT in schizophrenia and serotonin-dopamine interaction.

• Journal of Microbiology and Biotechnology
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• v.16 no.8
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• pp.1216-1221
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• 2006

A protein array was fabricated for a miniaturized immunoassay using microcontact printing ($\mu$CP). A polydimethylsiloxane (PDMS) stamp with a 5 $\mu$m$\times$5 /$\mu$m dimension was molded from a silicon master developed by photolithography. Under optimal fabrication conditions, including the baking, incubation, and exposure time, a silicon master was successfully fabricated with a definite aspect ratio. An antibody fragment was utilized as the ink for the $\mu$CP, and transferred to an Au substrate because of the Au-thiol (-SH) interaction. The immobilization and antibody-antigen interaction were investigated with fluorescence microscopy. When human serum albumin (HSA) was applied to the protein array fabricated with an antibody against HSA, the detection limit was 100 pg/ml of HSA when using a secondary antibody labeled with a fluorescence tag. The fabricated protein array maintained its activity for 14 days.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.12
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• pp.1785-1793
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• 2001

The interaction of growth hormone with it's receptor results in dimerization of receptor, a feature known in action of certain cytokines. The interaction results in generation of number of signalling molecules. The involvement of Janus kinases, mitogen activated kinases, signal transduction and activator of transcription proteins, insulin like substrate, phosphatidylinositol 3-kinase, phospholipase C, protein kinase C is almost established in growth hormone action. There are still many missing links in explaining diversified activities of growth hormone. Amino acid sequence data for growth hormones and growth hormone receptors from a number of species have proved useful in understanding species specific effects of growth hormone. Complete understanding of growth hormone action can have implications in designing drugs for obtaining desired effects of growth hormone.

• Laser Solutions
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• v.7 no.1
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• pp.29-36
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• 2004

The dynamics of laser-induced plasma/shock wave and the interaction with a surface in the laser shock cleaning process are analyzed by optical diagnostics. Shock wave is generated by a Q-switched Nd:YAG laser in air or with N$_2$, Ar, and He injection into the focal spot. The shock speed is measured by monitoring the photoacoustic probe-beam deflection signal under different conditions. In addition, nanosecond time-resolved images of shock wave propagation and interaction with the substrate are obtained by the laser-flash shadowgraphy. The results reveal the effect of various operation parameters of the laser shock cleaning process on shock wave intensity, energy-conversion efficiency, and flow characteristics. Discussions are made on the cleaning mechanisms based on the experimental observations.

• Bulletin of the Korean Chemical Society
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• v.34 no.2
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• pp.524-530
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• 2013

In this study, we describe the most expected behavior of cells on the modified surface and the correlation between the modified substrates and the response of cells. The physicochemical characteristics of substrates played an essential role in the adhesion and proliferation of cells. Glass and polymer substrates were modified using air plasma oxidation, and the surfaces were coated with self-assembled monolayer molecules of silanes. The PDMS substrates embedded with parallel micropatterns were used for evaluation of the effect of topologically modified substrate on cellular behaviour. BALB/3T3 fibroblast cells were cultured on different surfaces with distinct wettability and topology, and the growth rates and morphological change of cells were analyzed. Finally, we found the optimum conditions for the adhesion and proliferation of cells on the modified surface. This study will provide insight into the cell-surface interaction and contribute to tissue engineering applications.

• Journal of Magnetics
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• v.14 no.1
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• pp.15-17
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• 2009

The magnetostatic interaction between the two magnetic nanowires was studied by using the longitudinal magneto-optical Kerr effect (MOKE). For this purpose two magnetic nanowires having different widths (400 nm, 800 nm) were fabricated on an Si substrate with electron beam lithography and the lift-off method. Magnetic hysteresis loops measured by MOKE showed double switching behavior, corresponding to the separated switching fields of each wire. The switching field of the narrow wire was greatly affected by the separation between the two wires. Based on how the switching field changes with decreasing separation, it is concluded that the magnetostatic field of the 800-nm wire strongly affects the switching of the 400-nm wire when the separation is less than $0.5{\mu}m$.

• Bulletin of the Korean Chemical Society
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• v.9 no.3
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• pp.133-135
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• 1988

Kinetics and mechanism of the nucleophilic substitution reactions of phenacyl bromides with anilines in methanol-acetonitrile mixtures at $45.0^{\circ}C$ are reported. The reaction is found to proceed via $S_N2$ process, but the magnitudes of cross interaction constants, ${\rho}_{XY}$, between substituents X in the nucleophile and Y in substrate were unusually small, even after allowing for the fall off due to non-conjugative intervening -CO group in the reactant. As in the other phenacyl derivatives, the resonance shunt phenomenon was invoked to explain the remarkable diminuation of the $|{\rho}_{XY}|$ values.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1121-1124
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• 2007

Ink jet printing has been targeted as a key technology for OLED, TFT backplane and other organic semiconductor device fabrication. This presentation will concentrate on aspects of the IJ process, formulation design, jetting performance, interaction with the substrate and resultant printed device performance.