• Archives of Pharmacal Research
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• v.10 no.3
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• pp.173-178
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• 1987

Several new pyrazolo [1, 5-a]-S-triazine, pyrazolo [4, 5, -elpyrimidine, pyrazolo [1, 5-a] pyrimidine derivatives were synthesized via condensation of 3-antipyrinyl-5-amino-pyrazole (2) with $\beta$$-bifunctional reagents. The azo analogues of pyrazolo [1, 5-a] pyrimidines ; i. e. pyrazolo [5, 1, c]-as-triazine and pyrazolo[5, 1, -c]-as-benzotriazine were synthesized by coupling of diazotized 2-with agents containing active hydrogen.

• Bulletin of the Korean Chemical Society
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• v.30 no.5
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• pp.1187-1189
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• 2009

• Bulletin of the Korean Chemical Society
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• v.22 no.11
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• pp.1207-1212
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• 2001

A new photochemically bifunctional epoxy and dimethacrylate compounds were synthesized for investigating the photosensitivity under UV irradiation. Photosensitivity of the synthesized chalcone-based compounds was investigated by using UV-visible absorption and Fourier transformed infrared (FT-IR) spectroscopies. The result of spectroscopic analysis substantiated that the two chalcone-based compounds have functions of both photocrosslinking and photopolymerization by UV exposure in the presence of photoinitiator. Two kinds of photochemical reactions proceeded competitively during UV exposure. Particularly, we studied the effect of photopolymerization on the rate of photocrosslink due to cycloaddition in the two oligomeric compounds.

• Journal of Microbiology and Biotechnology
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• v.18 no.4
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• pp.746-753
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• 2008

The hprK gene encoding bifunctional HPrK/P (kinase/phosphorylase) was cloned from L. mesenteroides SY1, a strain isolated from kimchi. hprK was transcribed as a monocistronic gene. His-tagged HPrH16A and HPrK/P were produced in E. coli BL21 (DE3) using pET26b(+) and purified. HPrK/P phosphorylation assay with purified proteins showed that the kinase activity of HPrK/P increased at slightly acidic pHs. Divalent cations such as $Mg^{2+}$ and $Mn^{2+}$ and glycolytic intermediates such as fructose-1, 6-bisphosphate (FBP) and phosphoenolpyruvate (PEP) increased the kinase activity of HPrK/P, but inorganic phosphate strongly inhibited it. Kinetic studies for the kinase activity of HPrK/P showed that the apparent $K_m$ values were 0.18 and $14.57{\mu}M$ for ATP and HPr, respectively. The $K_m$ value for the phosphorylase activity of HPrK/P was $14.16{\mu}M$ for P-Ser-HPr (HPr phosphorylated at the serine residue).

• Journal of Microbiology and Biotechnology
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• v.19 no.10
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• pp.1077-1084
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• 2009

A genomic library was constructed to clone a xylanase gene (Mxyn10) from Demequina sp. JK4 isolated from a deep sea. Mxyn10 encoded a 471 residue protein with a calculated molecular mass of 49 kDa. This protein showed the highest sequence identity (70%) with the xylanase from Streptomyces lividans. Mxyn10 contains a catalytic domain that belongs to the glycoside hydrolase family 10 (GH10) and a carbohydrate-binding module (CBM) belonging to family 2. The optimum pH and temperature for enzymatic activity were pH 5.5 and $55^{\circ}C$, respectively. Mxyn10 exhibited good pH stability, remaining stable after treatment with buffers ranging from pH 3.5 to 10.0. The protein was not significantly affected by a variety of chemical reagents, including some compounds that usually inhibit the activity of other related enzymes. In addition, Mxyn10 showed activity on cellulose. These properties mark Mxyn10 as a potential enzyme for industrial application and saccharification processes essential for bioethanol production.

• Journal of Microbiology and Biotechnology
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• v.20 no.1
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• pp.88-93
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• 2010

Superoxide dismutase (SOD), glutathione peroxidase (GPX), and catalase (CAT) play crucial roles in balancing the production and decomposition of reactive oxygen species (ROS) in living organisms. These enzymes act cooperatively and synergistically to scavenge ROS. In order to imitate the synergism of these enzymes, we designed and synthesized a novel 32-mer peptide (32P) on the basis of the previous 15-mer peptide with GPX activity and a 17-mer peptide with SOD activity. Upon the selenation and chelation of copper, the 32-mer peptide was converted to a new Se- and Cu-containing 32-mer peptide (Se-Cu-32P) that displayed both SOD and GPX activities, and its kinetics was studied. Moreover, the novel peptide was demonstrated to be able to better protect vero cells from the injury induced by the xanthine oxidase (XOD)/xanthine/$Fe^{2+}$ damage system than its parents. Thus, this bifunctional enzyme imitated the synergism of SOD and GPX and could be a better candidate of therapeutic medicine.

• Composites Research
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• v.17 no.6
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• pp.37-43
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• 2004

To determine the effect of chain length and chemical structure of linear amine curing agents on thermal and mechanical properties, a standard bifunctional linear DGEBF epoxy resin was cured with EDA and HMDA having amine group at the both ends of main chain in a stoichiometrically equivalent ratio in condition of preliminary and post cure. From this work, the effect of linear amine curing agents on the thermal and mechanical properties is significantly influenced by numbers of carbon atoms of main chain. In contrast, the results show that the DCEBF/EDA system having two carbons had higher values in the thermal stability, density, shrinkage (%), grass transition temperature, tensile modulus and strength, flexural modulus and strength than the DGEBF/HMDA system having six carbons, whereas the DGEBF/EDA cure system had relatively low values in maximum ekothermic temperature, maximum conversion of epoxide, thermal expansion coefficient than the DGEBF/HDMA cure system. These findings indicate that the packing capability (rigid property) in the EDA structure affects the thermal and mechanical properties predominantly. It shows that flexural fracture properties have a close relation to flexural modulus and strength.

• BMB Reports
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• v.35 no.3
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• pp.273-282
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• 2002

Sp3 is a bifunctional transcription factor that has been reported to stimulate or repress the transcription of numerous genes. Although the size of Sp3 mRNA is 4.0kb, the size of the known Sp3 cDNA sequence is 3.6kb. Thus, Sp3 functional studies have been performed with an artificially introduced start codon, and thus an amino-terminus that differs from the wild-type. Ideally, full-length cDNA expression vectors with the appropriate start codon should be utilized for these studies. Using 5'rapid amplification of cDNA ends, a full-length Sp3 cDNA clone was generated and the sequence verified in nine cell lines. No AUG initiation codon was present. However, stop codons were present in all three frames 5' to the known coding sequence. In vitro translation of this full-length cDNA clone produced the expected three isoforms-one at 100 kDa and two in the mid 60 kDa range. Electrophoretic mobility shift assays showed that the protein products had the ability to bind to the Sp1/3 consensus sequence. In vitro studies, using our Sp3 clone and site directed mutagenesis, identified the translation initiation site for the larger isoform as AUA. AUA has not been previously described as an endogenous initiation codon in eukaryotes.

• Journal of Electrochemical Science and Technology
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• v.8 no.1
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• pp.7-14
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• 2017

This study aims to examine the influences of substrates/diffusion layers (DL) and oxygen reduction reaction catalysts ($M_{ORR}$) on the performance of $M_{ORR}/IrO_2$/DL-type bifunctional oxygen electrodes for use in polymer electrolyte membrane (PEM)-type unitized regenerative fuel cells (URFC). The $M_{ORR}/IrO_2$/DL electrodes were prepared via two sequential steps: anodic electrodeposition of $IrO_2$ on various DLs and fabrication of $M_{ORR}$ layers (Pt, Pd, and Pt-Ru) by spraying on $IrO_2/DL$. Experiments using different DLs, with Pt as the $M_{ORR}$, revealed that the roughness factor of the DL mainly determined the electrode performance for both water electrolyzer (WE) and fuel cell (FC) operations, while the contributions of porosity and substrate material were insignificant. When Pt-Ru was utilized as the $M_{ORR}$ instead of Pt, WE performance was enhanced and the electrode performance was assessed by analyzing round-trip efficiencies (${\varepsilon}_{RT}$) at current densities of 0.2 and $0.4A/cm^2$. As a result, using Pt-Ru instead of Pt alone provided better ${\varepsilon}_{RT}$ at both current densities, while Pd resulted in very low ${\varepsilon}_{RT}$. Improved efficiency was related to the additional catalytic action by Ru toward ORR during WE operation.

• Clean Technology
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• v.20 no.2
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• pp.116-122
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• 2014

Various types of MOFs (metal-organic frameworks) were prepared via hydrothermal and post-grafting methods and applied as catalysts for the synthesis of jasminaldehyde, one of the representative perfume intermediates, by Aldol condensation of benzaldehyde with heptanal. Although both acid and base sites could catalyze the reaction, the catalytic performance was strongly dependent on the physical properties as well as the nature of functionalization on MOFs. While the use of sulfonated MOF catalysts led to decrease of jasminaldehyde selectivity regardless of MOFs used, the selectivity change was found to rely on the MOF types in the case of the amine-functionalization. Among the catalysts tested, MIL-101 shows the best catalytic performance, which may suggest that MIL-101 has suitable acid properties to promote the Aldol condensation and the large pore of MIL-101 is also advantageous to alleviate the diffusion problem of bulky products.