• Journal of the Mineralogical Society of Korea
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• v.19 no.2 s.48
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• pp.81-88
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• 2006

The Yttria Partially Stabilized Zirconia powder was prepared by spontaneous precipitation method using $ZrOCl_2{\cdot}8H_O-YCl_33{\cdot}6H_2O$ solution as a starting materials. The optimal experimental conditions such as concentration and pH of starting solutions, the amounts of stabilizer $Y_2O_3$ used, and sintered temperature were carefully studied. The best condition for synthesizing $ZrO_2$ was experimentally selected and applied throughout this study for the preparation of the 3 mole% $Y_2O_3$ partially stabilized zirconia, 3YSZ. The physical properties of 3YSZ was examined by XRD, Raman, DT A, and SEM. The structural transition from pure monoclinic high temperature $ZrO_2$ to tetragonal room temperature 3YSZ was made possible by the added amount of $Y_2O_3$ in the $ZrO_2+Y_2O_3$ system. All Raman Spectrum band appeared in the lower wave numbers rather than in higher wave numbers as structure changes from monoclinic to tetragonal.

• Journal of Microbiology
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• v.43 no.3
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• pp.285-294
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• 2005

A bacterial strain M4-7 capable of degrading various polyesters, such as poly$(\varepsilon-caprolactone)$, poly(3-hydroxybutyrate-co-3-hydroxyvalerate), poly(3-hydroxyoctanoate), and poly(3-hydroxy-5-phenylvalerate), was isolated from a marine environment and identified as Pseudomonas alcaligenes. The relative molecular mass of a purified extracellular medium-chain-length poly(3-hydroxyalkanoate) (MCL-PHA) depolymerase $(PhaZ_{palM4-7})$ from P. alcaligenes M4-7 was 28.0 kDa, as determined by SDS-PAGE. The $PhaZ_{palM4-7}$ was most active in 50 mM glycine-NaOH buffer (pH 9.0) at $35^{\circ}C$. It was insensitive to dithiothreitol, sodium azide, and iodoacetamide, but susceptible to p-hydroxymercuribenzoic acid, N-bromosuccinimide, acetic anhydride, EDTA, diisopropyl fluorophosphate, phenylmethylsulfonyl fluoride, Tween 80, and Triton X-100. In this study, the genes encoding MCL-PHA depolymerase were cloned, sequenced, and characterized from a soil bacterium, P. alcaligenes LB19 (Kim et al., 2002, Biomacro-molecules 3, 291-296) as well as P. alcaligenes M4-7. The structural gene $(phaZ_{palLB19})$ of MCL-PHA depolymerase of P. alcaligenes LB19 consisted of an 837 bp open reading frame (ORF) encoding a protein of 278 amino acids with a deduced $M_r$ of 30,188 Da. However, the MCL-PHA depolymerase gene $(phaZ_{palM4-7})$ of P. alcaligenes M4-7 was composed of an 834 bp ORF encoding a protein of 277 amino acids with a deduced Mr of 30,323 Da. Amino acid sequence analyses showed that, in the two different polypeptides, a substrate-binding domain and a catalytic domain are located in the N-terminus and in the C-terminus, respectively. The $PhaZ_{palLB19}$ and the $PhaZ_{palM4-7}$ commonly share the lipase box, GISSG, in their catalytic domains, and utilize $^{111}Asn$ and $^{110}Ser$ residues, respectively, as oxyanions that play an important role in transition-state stabilization of hydrolytic reactions.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.31 no.2
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• pp.58-69
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• 2013

This research try to review about individuals' living culture place by record to before process of transition and modify of Bugundang village's forest in Itaewon. A result is as follows. First, Itaewon Bugundang is located in highest site of center building of twon forest, it has been preserve by double fence and taboo subject. Physical element of village forest is a factor which give sanctity of Buhundang. Second, it is connecting Namsan and Yongsan Family Park as green space. Also Itaewon Bugundang isolated from the current residential area. but in the past, the main beliefs and rituals of its area are responsible for a diverse community where public service was strong. Itaewon Bugundang have played a role presenting a local taboos and social norms. Therefore, these elements of the local community have the traditional cultural values. Third, Zelkova and Kalopanax pictus need to be preserved the value by the Seoul Metropolitan Government. Fourth, components of Bugundang are built by Hwajucheong, Dangjigi house, seonangdan, monument, fence, masonry and various trees. And the function and role of each of these elements remains as traditional culture. And the structural features of historic architectural properties has the value as a registered cultural properties. Fifth, due to these features, the traditional landscape of Itaewon bugundang play a role succeeding disappearing traditional culture and is worth as a potentially valuable landscape elements. This study has significance to the excavation community tradition disappearing landscape and excavation of candidate new tradition.

• Journal of Korea Technology Innovation Society
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• v.19 no.2
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• pp.324-357
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• 2016

As the transition to the knowledge-based economy has been accelerated in the 21st century, the importance of the service industry has been highlighted. As the proportion of knowledge service industry in the economy and the related employment rate are continuously growing, it is necessary to bring innovation to the industry in order to increase competitiveness. In this study, the innovation types are diversified into product, process, organization, and marketing and the influencing factors have been analyzed with knowledge service firms. The complex causal relationship that is linked to the innovation performance has been analyzed by the structural equation with each innovation types as the intervening variables. The results of this study can be summarized as follows. The innovation capacity of firms in knowledge service industry has very strong positive effects either directly or indirectly on product innovation, process innovation, organizational innovation, marketing innovation, and the revenue and employment of the firm. On the other hand, innovation support policy through government intervention produce negative impact on product innovation and they do not create meaningful impact on the total effect on the revenue nor the employment growth. The innovation should ultimately create effects on the revenue and the employment of the firm. And the government support policies should be carefully designed in consideration of the final destination point of this complex causal structure.

• Journal of Technology Innovation
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• v.21 no.2
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• pp.85-113
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• 2013

This study analyzes the government-funded research institutions as players which derive inner transition based on technology, policy and market environment changes. In this study, the main case is KRICT(Korea Research Institute of Chemical Technology) which tries to make post catch-up innovation in the organization. This institution has attempted to overcome the limitation such as change of technology paradigm and PBS(Project Based System) since 2000's. Responding to the needs of technology convergence and innovation by the paradigm change, KRICT has reformed organization and R&D management system prospectively. And this institution sets the goal like development of natural friendly technologies, small and medium-sized business support, and providing countermeasures of social problems. This case shows possibility of continuous innovation. There are some structural limitation like budget restriction, multiple organization structure, and biased quantitative assessment, but endogenous efforts of government -funded institutions make the new paradigm of post catch-up innovation.

• Journal of the Korean Society for Nondestructive Testing
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• v.21 no.4
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• pp.439-445
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• 2001

The destructive method is reliable and widely used lot the estimation of material degradation but, it have time-consuming and a great difficulty in preparing specimens from in-service industrial facilities. Therefore, the estimation of degraded structural materials used at high temperature by nondestructive evaluation such as electric resistance method, replica method, Barkhausen noise method, electro-chemical method and ultrasonic method are strongly desired. Ultrasonic nondestructive evaluation technique has been reported good to attain efficiency of measurement, high sensitivity of measurement, and rapidity and reliability of result interpretation. In this study, it was verified experimentally the feasibility of the evaluation of degraded 2.25Cr-1Mo steel specimens which were prepared by the isothermal aging heat treatment at $630^{\circ}C$ by high frequency longitudinal wave method investigating the change of attenuation coefficient by FFT analysis and wavelet transform. Because of carbide precipitation increase and spheroidization near grain boundary of microstructure to aging degradation, attenuation coefficient had a tendency to increase as degradation proceeded. It was identified possibly to evaluate degradation using the characteristics of high-frequency ultrasonics. Frequency dependence of ultrasonic attenuation coefficient to aging degradation appeared large, which made sure that attenuation coefficient is an important parameter for evaluation of aging degradation.

• Korean Journal of Microbiology
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• v.43 no.3
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• pp.159-165
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• 2007

For the development of basic genetic materials for specific and effective therapeutic approach to suppress multiplication of hepatitis C virus (HCV), HCV internal ribosome entry site (IRES)-targeting hammerhead ribozyme which activity is allosterically regulated by HCV regulatory protein, NS5B RNA replicase, was developed. The ribozyme targeted most effectively to +382 nucleotide (nt) site of HCV IRES RNA. The allosteric ribozyme was designed to be composed of sequence of RNA aptamer to HCV NS5B, communication module sequence which can transfer structural transition for inducing ribozyme activity upon binding NS5B to the aptamer, and sequence of ribozyme targeting +382 nt of HCV IRES. Noticeably, we employed in vitro selection technology to identify the most appropriate communication module sequence which can induce ribozyme activity depending on the US5B protein. We demonstrated that the ribozyme was nonfunctional either in the absence of any proteins or in the presence of control bovine serum albumin. In sharp contrast, the allosteric ribozyme can induce activity of cleavage reaction with HCV IRES RNA in the presence of the HCV NS5B protein. This allosteric ribozyme can be used as lead compound for specific and effective anti-HCV agent, tool for highthroughput screening to isolate lead chemicals for HCV therapeutics, and ligand for biosensor system for HCV diagnosis.

• Korean Journal of Microbiology
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• v.44 no.3
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• pp.186-192
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• 2008

For the development of specific and effective basic genetic materials to inhibit replication of hepatitis C virus (HCV), HCV genome-targeting trans-splicing aptazyme, which activity is allosterically regulated by a specific ligand, was developed. The aptazyme was designed to be comprised of sequence of RNA aptamer to the ligand, communication module sequence which can transfer structural transition for inducing ribozyme activity upon binding the ligand to the aptamer, and trans-splicing ribozyme targeting +199 nt of HCV IRES. Especially, when the aptamer and the communication module was inserted at both P6 and P8 catalytic domain of the specific ribozyme, allosteric activity of the aptazyme was the most induced. The aptazyme was shown to induce activity of trans-splicing reaction specifically and efficiently only in the presence of the specific ligand, but neither in the absence of any ligand nor in the presence of control ligand. This aptazyme can be used as a specific and effective genetic agent against HCV, and a tool for the isolation of anti-HCV lead compounds.

• Development and Reproduction
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• v.13 no.3
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• pp.183-190
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• 2009

In mammals, puberty is a dynamic transition process from infertile immature state to fertile adult state. The neuroendocrine aspect of puberty is started with functional activation of hypothalamus-pituitary-gonadal hormone axis. The timing of puberty can be altered by many factors including hormones and/or hormone-like materials, social cues and metabolic signals. For a long time, attainment of a particular body weight or percentage of body fat has been thought as crucial determinant of puberty onset. However, the precise effect of high-fat (HF) diet on the regulation of hypothalamic GnRH neuron during prepubertal period has not been fully elucidated yet. The present study was undertaken to test the effect of a HF diet on the puberty onset and hypothalamic gene expressions in immature female rats. The HF diet (45% energy from fat, HF group) was applied to female rats from weaning to around puberty onset (postnatal days, PND 22-40). Body weight and vaginal opening (VO) were checked daily during the entire feeding period. In the second experiment, all animals were sacrificed on PND 36 to measure the weights of reproductive tissues. Histological studies were performed to assess the effect of HF diet feeding on the structural alterations in the reproductive tissues. To determine the transcriptional changes of reproductive hormone-related genes in hypothalamus, total RNAs were extracted and applied to the semi-quantitative reverse transcription polymerase chain reaction (RT-PCR). Body weights of HF group animals tend to be higher than those of control animals between PND 22 and PND 31, and significant differences were observed PND 32, PND 34, PND 35 and PND 36 (p<0.05). Advanced VO was shown in the HF group (PND $32.8{\pm}0.37$ p<0.001) compared to the control (PND $38.25{\pm}0.25$). The weight of ovaries (p<0.01) and uteri (p<0.05) from HF group animals significantly increased when compared to those from control animals. Corpora lutea were observed in the ovaries from the HF group animals but not in control ovaries. Similarly, hypertrophy of luminal and glandular uterine epithelia was found only in the HF group animals. In the semi-quantitative RT-PCR studies, the transcriptional activities of KiSS-1 in HF group animals were significantly higher than those from the control animals (p<0.001). Likewise, the mRNA levels of GnRH (p<0.05) were significantly elevated in HF group animals. The present study indicated that the feeding HF diet during the post-weaning period activates the upstream modulators of gonadotropin such as GnRH and KiSS-1 in hypothalamus, resulting early onset of puberty in immature female rats.

• Bulletin of the Korean Chemical Society
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• v.33 no.1
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• pp.48-54
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• 2012

The $[Fe_4S_4]^{2+}$ clusters with 2-, 3-, and 4-pyridinemethanethiolate (S2-Pic, S3-Pic, and S4-Pic, respectively) terminal ligands have been synthesized from the ligand substitution reaction of the $(^nBu_4N)_2[Fe_4S_4Cl_4]$ (I) cluster. The new $(^nBu_4N)_2[Fe_4S_4(SR)_4]$ (R = 2-Pic; II, 3-Pic; III, 4-Pic; IV) clusters were characterized by FTIR and UV-Vis spectroscopy. Cluster II was crystallized in the monoclinic space group C2/c with a = 24.530 (5) $\AA$, b = 24.636(4) $\AA$, c = 21.762(4) $\AA$, ${\beta}=103.253(3)^{\circ}$, and Z = 8. The X-ray structure of II showed two unique 2:2 site-differentiated $[Fe_4S_4]^{2+}$ clusters due to the bidentate-mode coordination by 2-pyridinemethanethiolate ligands. Cluster III was crystallized in the same monoclinic space group C2/c with a = 26.0740(18) $\AA$, b = 23.3195(16) $\AA$, c = 22.3720(15) $\AA$, ${\beta}=100.467(2)^{\circ}$, and Z = 8. The 3-pyridinemethanethiolate ligand of III was coordinated to the $[Fe_4S_4]^{2+}$ core as a terminal mode. Cluster IV with 4-pyridinemethanethiolate ligands was found to have a similar structure to the cluster III. Fully reversible $[Fe_4S_4]^{2+}/[Fe_4S_4]^+$ redox waves were observed from all three clusters by cyclic voltammetry measurement. The electrochemical potentials for the $[Fe_4S_4]^{2+}/[Fe_4S_4]^+$ transition decreased in the order of II, III and IV, and the reduction potential changes by the ligands were explained based on the structural differences among the complexes. The complex III was reacted with sulfonium salt of $[PhMeSCH_2-p-C_6H_4CN](BF_4)$ in MeCN to test possible radical-involving reaction as a functional model of the [$Fe_4S_4$]-SAM (S-adenosylmethionine) cofactor. However, the isolated reaction products of 3-pyridinemethanethiolate-p-cyanobenzylsulfide and thioanisole suggested that the reaction followed an ionic mechanism and the products formed from the terminal ligand attack to the sulfonium.