• Microbiology and Biotechnology Letters
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• v.47 no.4
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• pp.667-672
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• 2019

We compared two integration systems for stable expression of heterologous genes in Saccharomyces cerevisiae. A Candida glabrata-derived gene was used as the selective marker for the Cre/loxP system, and XYLP, XYLB, GRE3, and XYL2 genes were used as model heterologous genes and ligated into the universal pRS-CMT vector. The resulting pRS-XylP, pRS-XylB, pRS-Gre3, and pRS-Xyl2 plasmids were sequentially integrated into yeast chromosome VII by four integration processes (marker rescue and gene integration). The four introduced genes were successfully expressed. Further, the pRS-PBG2 plasmid harboring expression cassettes for the four genes was constructed for one-step integration. The four genes that were introduced were stably maintained as a gene cluster and were simultaneously expressed. The one-step integration was more effective for the simultaneous integration and expression of the four genes related to xylan/xylose metabolism. This method will enable the generation of a useful biosystem through appropriate use of gene integration methods.

• Microbiology and Biotechnology Letters
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• v.34 no.1
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• pp.58-62
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• 2006

Rapid assay of enzyme is a primary requirement for successful application of directed evolution technology. Halo generation on a turbid plate would be a method of choice for high throughput screening of enzymes in this context. Here we report a new approach to prepare turbid plates, by controlling the crystallization of tyrosine to form needle-like particles. In the presence of tyrosine phenol-lyase (TPL), the needle-like tyrosine crystals were converted to soluble phenol rapidly than the usual rectangular tyrosine crystals. When an error-prone PCR library of Citrobacter freundii TPL was spread on the turbid plate, approximately 10% of the colonies displayed recognizable halos after 24 hours of incubation at $37^{\circ}C$. Representative positives from the turbid plates were transferred to LB-medium in 96-wellplates, cultivated overnight, and assayed for the enzyme activity with L-tyrosine as the substrate. The assay results were approximated to be proportional to the halo size on turbid plates, suggesting the screening system is directly applicable to the directed evolution of TPL. Actually, two best mutants on the turbid plates were identified to be $2{\sim}2.5$ and 1.5-fold improved in the activity.

• The Journal of the Korea Contents Association
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• v.17 no.2
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• pp.521-534
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• 2017

In 2013 the Netflix, an OTT in USA, launched all at once 13 episodes of the House of Cards season. Binge-watching is the word which means watching continuously 2~6 episodes of a TV program with one sitting, the new normal of TV watching behavior, cultural and social currents all over the world. This study has analyzed the factors and motivations which affect to the persistent intention to use binge-watching. It conducted an online survey from 333 Quota sample from Korean age groups between 20th~60th with 81 questionnaires. The 5 groups were induced as motivation factors to binge-watching. The 3 groups which consisted of , , are affecting as positive to intention to use binge-watching. But the other 2 groups which are and doing as negative. The survey has shown that the persistent intention to binge-watching is affected by ages more younger, whom doing binge watching more frequently, whom estimating more higher to the conceived usefulness to use. As a theoretical model, expanded technology acceptance model was adopted and US drama House of Cards. This study could promote the next generation contents planning and S-VOD service industry.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.2
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• pp.324-334
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• 2017

The simulators for a plant unit master control (UMC) developed by domestic or overseas researchers have been developed for operator-training purposes. UMC simulators normally constructed at the end of the plant construction, despite the UMC logics, should be simulated to pre-check many signal interfaces within the power generation systems. Because of the differences in construction schedule, it is difficult for logic designers or commissioning engineers to simulate the UMC logic during the design or commissioning stage. In this background, this paper proposes a simulation method that can be used easily by plant logic designers or operators in the MATLAB Simulink programming environment. The core of the UMC is realized with a unique simulation algorithm based on mathematical analysis and functional blocks combination. In addition, an integer-based configuration was proposed to realize the plant target value control for the equipment in the logic. With these simulation methods, functions, e.g., load distribution, high-low limitations, frequency compensation, etc. were simulated. The results showed that the plant UMC logic can be simulated in Simulink without a plant simulator. The various functions proposed in this paper can provide useful information about Simulink-based simulation design for plant logic designers or commissioning engineers during the power plant construction period.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.11
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• pp.589-595
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• 2016

This study evaluated the environmental impacts for landfill treatment of the wastewater treatment sludge (WTS) from petrochemical firms by life cycle assessment (LCA) and reviewed the impact reduction by landfill gas (LFG) utilization. The functional unit was 'landfill of 1 ton of WTS', and the system boundary included the process of input and treatment for WTS in landfill site. The impacts were high at landfill process (LP) and leachate treatment process (LTP). Global warming (GWP) and photochemical oxidants creation (POCP) were high at LP, while abiotic depletion (ADP), acidification (AP), eutrophication (EP), ozone depletion (ODP) were high at LTP. The major substances of various impact categories were crude oil (ADP), $NO_X$ (AP, EP), $CH_4$ (GWP, POCP), $Cl_2$ (ODP), respectively. The major factor of ADP, AP, EP was attributed from the generation of electricity used in LTP, and the methane within uncollected LFG was main factor of GWP and POCP. Therefore, electricity consumption reduction is identified to be an impact improvement option, and the flaring system installation or enhanced LFG recovery could be an alternative to reduce impacts. Among the various categories, GWP accounted the highest impact (${\geq}90%$) followed by ADP, POCP. In the avoidance impact resulted from the utilization of LFG, to substitute B-C oil or LNG showed the impact reduction of 32.7% and 12.0%, respectively.

• The Korean Journal of Physiology and Pharmacology
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• v.7 no.6
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• pp.325-331
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• 2003

3-Nitropropionic acid (3-NP) inhibits electron transport in mitochondria, leading to a metabolic failure. In order to elucidate the mechanism underlying this toxicity, we examined a few biochemical changes possibly involved in the process, such as metabolic inhibition, generation of reactive oxygen species (ROS), DNA strand breakage, and activation of Poly(ADP-ribose) polymerase (PARP). Exposure of SK-N-BE(2)C neuroblastoma cells to 3-NP for 48 h caused actual cell death, while inhibition of mitochondrial function was readily observed when exposed for 24 h to low concentrations (0.2${\sim}$2 mM) of 3-NP. The earliest biochemical change detected with low concentration of 3-NP was an accumulation of ROS (4 h after 3-NP exposure) followed by degradation of DNA. PARP activation by damaged DNA was also detectable, but at a later time. The accumulation of ROS and DNA strand breakage were suppressed by the addition of glutathione or N-acetyl-L-cysteine (NAC), which also partially restored mitochondrial function and cell viability. In addition, inhibition of PARP also reduced the 3-NP-induced DNA strand breakage and cytotoxicity. These results suggest that oxidative stress and activation of PARP are the major factors in 3-NP-induced cytotoxicity, and that the inhibition of these factors may be useful in protecting neuroblastoma cells from 3-NP-induced toxicity.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.8
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• pp.4086-4092
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• 2013

Mycosporine-like amino acids (MAAs) are UV-absorbing substances, and diverse marine organisms have the evolved the capacity to diminished the direct and indirect damaging effects of environmental ultraviolet radiation by synthesis and accumulation of MAAs. In this study, we manufactured a radiofrequency (RF) generation device and applied to microalgal culture. $0.35{\pm}0.05$ mHz of RF was supplied to culture vessel for Chlamydomonas sp. and samples were harvested at the designated time intervals (1, 0.5, 1 and 2 hr). MAAs biosynthetic genes, dehydroquinate synthase homolog (DHQS-like) and nonribosomal peptide synthetase homolog (NRPS-like), were cloned from Chlamydomonas sp. and their gene expressions under the RF exposure were analyzed using qRT-PCR. DHQS-like and NRPS-like gene expressions of Chlamydomonas sp. exposed to RF were increased 1.46 and 1.19 fold at 1 hr, respectively. These results means that DHQS-like and NRPS-like genes can be good biomarker candidates for diagnosis of MAAs biosynthesis in the Chlamydomonas sp.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.8C
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• pp.633-641
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• 2008

Since WSNs encounter attacks, such as jamming or eavesdropping without physical access occurs, security is one of the important requirements for WSNs. The key pre-distribution scheme that was recently researched for advance of security in WSNs distributes the keys and probability with the use of q-composite random key pre-distribution method, but there is a high probability that no key shared between sensor nodes, and it takes a lot of time and energy to find out the shared key. Therefore, it is not suitable for WSNs. In order to enhance stability of a node that plays a role of gateway without depending on probabilistic key, this paper proposesa key pre-distribution scheme combined with random key pre-distribution scheme and double hash chain. Since the proposed scheme can maintain a small storage place and strong security strengths, it is more efficient than the existing schemes with the same security strengths. In addition, since it uses a small size of key generation key set, it can reduce a great deal of storage overhead.

• Progress in Superconductivity
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• v.12 no.2
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• pp.118-123
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• 2011

The properties of $2^{nd}$ generation high temperature superconducting wire, coated conductor strongly depend on the quality of superconducting oxide layer and property of metal substrate is one of the most important factors affecting the quality of coated conductor. Good mechanical and chemical stability at high temperature are required to maintain the initial integrity during the various process steps required to deposit several layers consisting coated conductor. And substrate need to be nonmagnetic to reduce magnetization loss for ac application. Hastelloy and stainless steel are the most suitable alloys for metal substrate. One of the obstacles in using stainless steel as substrate for coated conductor is its difficulties in making smooth surface inevitable for depositing good IBAD layer. Conventional method involves several steps such as electro polishing, deposition of $Al_2O_3$ and $Y_2O_3$ before IBAD process. Chemical solution deposition method can simplify those steps into one step process having uniformity in large area. In this research, we tried to improve the surface roughness of stainless steel(SUS310). The precursor coating solution was synthesized by using yttrium complex. The viscosity of coating solution and heat treatment condition were optimized for smooth surface. A smooth amorphous $Y_2O_3$ thin film suitable for IBAD process was coated on SUS310 tape. The surface roughness was improved from 40nm to 1.8 nm by 4 coatings. The IBAD-MgO layer deposited on prepared substrate showed good in plane alignment(${\Delta}{\phi}$) of $6.2^{\circ}$.

• Journal of the Korean Society of School Health
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• v.11 no.1
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• pp.63-74
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• 1998

The purposes of this study are to show in interpersonal relations what factors male students are stressed from, how they experience stress, how they cope With it in each situation, and what this results in It attempt to gam basic materials to promote male student health and positive coping methods, The subject of this study was 15 male students of C University located in Seoul and Kyeonggui-Do They were composed of 5 sophomores, 5 Juniors and 5 seniors The period for collecting materials was October 1997 to January 1998, and the interview time ranged from 50 minutes to two hours The interview frequency was one to three times as occasion demanded, The materials were analyzed by the methods and theory suggested by Strauss & Corbin (1990) The results were 130 categories grouped into 33 divisions by similarity Finally, they were united into 9 higher categories In interpersonal relations the core category of male student stress is "affliction", and it follows the course of generation-coping-resolution The types showed in the course of material analysis are as follows, (1) When the subject student is on good terms with the other and the stress is repeated- "affliction" is strong and continuous-and his ability sense is strong, he copes with "affliction" With his own will and solves It affirmatively, (2) When the subject student is on good terms with the other and the stress is repeated-so "affliction" is strong and continuous-and his ability sense is weak, he copes with "affliction" with an emotional bias and solves it negatively (3) When the subject student is on good terms with the other and the stress is temporary-"affliction" is strong and temporary-and his ability sense is strong, he copes with "affliction" with his own will and solves it affirmatively (4) When the subject student becomes estranged from the other and the stress is temporary-"affliction" is weak and temporary-and his ability sense is weak, he copes with "affliction" with an emotional bias and solves it negatively, (5) When the subject student becomes estranged from the other and the stress is repeated-"affliction" is strong-and continuous and his ability sense is strong, he copes with "affliction" with his own will and solves it affirmatively (6) When the subject student becomes estranged from the other and the stress is repeated-"affliction" is strong and continuous-and his ability sense is weak, he copes with "affliction" with an emotional bias and solves it negatively. According to the above results, the conditions of cause and effect for male students to generate "affliction" should be understood in order to help cope with stress caused by interpersonal relations A program for education and counseling should be developed for male students to strengthen their 'ability sense' in choosing coping strategies In addition, the individual estimation for ability sense should be performed when education and counseling them.