• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.184-184
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• 2011

Using first-principles density-functional calculations, we investigate the chain reaction mechanism of allyl alcohol (ALA) molecules on the H-terminated Si(001)-2${\times}$1 surface. Recently, it was reported [1] that allyl mercaptan (ALM) molecules show a self-directed line growth across the dimer rows through a chain reaction involving several reaction processes: (i) The created radical at the C atom is transferred to the S atom, (ii) the resulting S-centered radical easily abstracts an H atom from the neighboring dimer row, and (iii) the generated S-H group further reacts with the neighboring dimer row to produce the Si-S bond on the neighboring dimer row, accompanying the associative desorption of H2. This H2-desorption process creates a new DB on the neighboring dimer row, setting off the chain reaction across the dimer rows. In the present study, we find that although the structure of ALA with -OH functional is analogous to that of ALM with -SH functional, ALA and ALM lines show a difference in their growth direction. We predict that ALA undergoes the chain reaction to show a line growth along the dimer row, contrasting with the ALM line growth across the Si dimer rows. Our analysis shows that the different growth direction of ALA is due to the strong instability of oxygen radical intermediate, which prevents from growing across the dimer rows. Thus, we demonstrate that the stability of the radical intermediate plays a crucial role in determining the direction of molecular line growth.

• Journal of the Korean Chemical Society
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• v.10 no.1
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• pp.25-31
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• 1966

It is well known that the coloration and structural changes in thermal treatment of polyacrylonitrile are due to the formation of partly hydrogenated naphthylidine-type ring involving the pendant nitrile groups. Any quantitative study of the reaction, in the sense of kinetics and/or statistics, however, has never been reported. This paper presents that, at first, the disappearance of the nitrile groups follows the first order kinetics, which indicates clearly that nitrile groups do not disappear by a long chain reaction-the kinetic chain length is very short. This observation rules out the long intramolecular and intermolecular propagation chain through which most of the nitrile groups disappear. From the evidence that a similar reaction occurs in propylene carbonate solutions without gel formation, one may conclude that the coloration and structural changes are not necessarily intermolecular reaction. Secondly, a finite amount of nitrile groups remains unreacted at the extrem of reaction-not contributed to the formation of naphthylidine-type ring. The concentration of this unreacted nitrile groups is 19∼22% which is good agreement with the statistically calculated value of 19.2%.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.375.1-375.1
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• 2016

Polymerase chain reaction (PCR) has revolutionized genetics and become one of the most popular techniques in modern biological and medical sciences. It can be used not only as an in vitro DNA amplification method but also used in many bioassay applications. The PCR can be used to exponentially produce a large number of DNA copies from a small quantity of DNA molecules in a few hours. However, as unwanted DNA fragments are also often manufactured, the amplification efficiency of PCR is decreased. To overcome this limitation, several nanomaterials have been employed to increase the specificity of the PCR reaction. Recently, graphene has attracted a great interest for its excellent electron transfer, thermal and biocompatibility. Especially, gold nanoparticle-coated graphene oxide (GO/AuNPs) led to enhance electron and thermal transfer rate and low-charge transfer resistance. Therefore, we report the development of a demonstration for the PCR efficiency using a large-scale production of the GO and combination of gold nanoparticles. Because a thermal conductivity is an important factor for improving the PCR efficiency in different DNA polymerases and different size samples. When PCR use GO/AuNPs, the result of transmission electron microscopy and real-time quantitative PCR (qPCR) showed an enhanced PCR efficiency. We have demonstrated that GO/AuNPs would be simply outperformed for enhancing the specificity and efficiency of DNA amplification procedure.

• Journal of the Korean Applied Science and Technology
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• v.10 no.1
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• pp.67-74
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• 1993

1, 2-Isopropylidene glycerol produced by ketalyzation of glycerol with aceton was esterified with long chain fatty acids in the presence of a Mucor miehei lipase to obtain 1, 2-isopropylidene 3-long chain acyl glycerol. To determine optimal conditions for the esterification reaction, esterification was proceeded as a reversible second-order reaction in various parameters that are enzyme/substrate ratio 0.096g/g at reaction temperatures ranged from $25^{\circ}C$ to $70^{\circ}C$. The order of reaction rate of fatty acids were lauric acid, myristic acid, oleic acid, and stearic acid. The range of their activation energies were from 7.8 to 11.4 (kcal/mol) and that of entropies of activation which have negative values were from 42.8 to 52.5(e.u.).

• Korean Journal of Veterinary Research
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• v.38 no.1
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• pp.101-106
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• 1998

The present study attempted to apply polymerase chain reaction (PCR) to develop a rapid differential diagnosis among Marek's disease, reticuloendotheliosis and avian leukosis. The primers chosen to detect Marek's disease virus (MDV) flank the 132bp tandem direct repeat of the MDV genome. The primers selected for reticuloendotheliosis virus (REV) and avian leukosis virus (ALV) are based on proviral long terminal repeats of spleen necrosis virus and Rous-associated virus-2 genomes, respectively. The specific PCR products of MDV, REV and ALV were observed with each primer and the reaction was not cross-reacted among the viruses. MDV-specific DNA was also amplified from the MDV-induced lymphoma (MDCC-MSB1) but not from the REV-induced tumor and ALV-induced lymphoma (LSCC-1104B1). In addition, proviral DNA of REV from REV-induced tumor and proviral DNA of ALV from ALV-induced lymphoma were also amplified by REV-specific and ALV-specific PCRs, respectively. Therefore these three PCR methods may be used to rapidly differentiate among MDV, REV and ALV-associated tumors in diagnosis.

• Korean Journal of Veterinary Research
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• v.57 no.1
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• pp.37-42
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• 2017

Getah virus (GETV) infection causes sporadic outbreaks of mild febrile illness in horses and reproductive failure in pigs. In this study, we established a reverse transcription polymerase chain reaction (RT-PCR) method to detect GETV from suspected virus-infected samples. The reaction conditions were optimized and validated by using RNA extracted from GETV propagated in cell culture. A GETV-specific GED4 primer set was designed and used to amplify a 177 bp DNA fragment from a highly conserved region of the E1 glycoprotein gene in the GETV genome. RT-PCR performed with this primer set revealed high sensitivity and specificity. In the sensitivity test, the GED4 primer set detected GETV RNA at the level of $10^{2.0}\;TCID_{50}/mL$. In the specificity test, the GED4 primer set amplified only a single band of PCR product on the GETV RNA template, without non-specific amplification, and exhibited no cross-reactivity with other viral RNAs. These results suggest that this newly established RT-PCR method is useful for accurate identification of GETV infection in animals.

• Journal of Microbiology and Biotechnology
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• v.33 no.2
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• pp.268-276
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• 2023

Alkyl butyrate with fruity flavor is known as an important additive in the food industry. We synthesized various alkyl butyrates from various fatty alcohol and butyric acid using immobilized Rhodococcus cutinase (Rcut). Esterification reaction was performed in a non-aqueous system including heptane, isooctane, hexane, and cyclohexane. As a result of performing the alkyl butyrate synthesis reaction using alcohols of various chain lengths, it was found that the preference for the alcohol substrate had the following order: C6 > C4 > C8 > C10 > C2. Through molecular docking analysis, it was found that the greater the hydrophobicity of alcohol, the higher the accessibility to the active site of the enzyme. However, since the number of torsions increased as the chain length increased, it became difficult for the hydroxyl oxygen of the alcohol to access the ^γO of serine at the enzyme active site. These molecular docking results were consistent with substrate preference results of the Rcut enzyme. The Rcut maintained the synthesis efficiency at least for 5 days in isooctane solvent. We synthesized as much as 452 mM butyl butyrate by adding 100 mM substrate daily for 5 days and performing the reaction. These results show that Rcut is an efficient enzyme for producing alkyl butyrate used in the food industry.

• Journal of the Korean Chemical Society
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• v.49 no.3
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• pp.255-260
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• 2005

• Korean Journal Plant Pathology
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• v.10 no.3
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• pp.157-162
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• 1994

Erwinia rhapontici causes soft-rot disease in a number of plants such as onion, garlic and hyacinth. There has been no report that E. rhapontici produces pectate lyase. Pel gene was cloned from genomic DNA of the parasitic soft-rot E. rhapontici polymerase chain reaction by using synthetic oligonulceotide primers designed from the pel 1 to E. carotovora. The recombinant plasmid pJE101 containing pectate lyase gene, when introduced into E. coli DH5$\alpha$, produced pectate lyase an macerated hyacinth tissue.

• Journal of Animal Reproduction and Biotechnology
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• v.34 no.4
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• pp.259-266
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• 2019

Emulsion polymerase chain reaction (PCR) is performed on compartmentalized DNA, allowing a large number of PCR reactions to be carried out in parallel. Emulsion PCR has unique advantages in DNA amplification. It can be applied in many molecular biological assays, especially those requiring highly sensitive and specific DNA amplification. This review discusses the principle of emulsion PCR and its applications in biotechnology. Related technologies are also discussed.