• Journal of electromagnetic engineering and science
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• v.16 no.3
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• pp.143-149
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• 2016

This work presents a method used for designing a broadband class-E power amplifier that combines the two techniques of a nonlinear shunt capacitance and a low quality factor of a series resonator. The nonlinear shunt capacitance theory accurately extracts the value of class-E components. In addition, the quality factor of the series resonator was considered to obtain a wide bandwidth for the power amplifiers. The purpose of using this method was to produce a simple topology and a high efficiency, which are two outstanding features of a class-E power amplifier. The experimental results show that a design was created using from a 130 to 180 MHz frequency with a bandwidth of 32% and a peak measured power added efficiency of 84.8%. This prototype uses an MRF282SR1 MOSFET transistor at a 3-W output power level. Furthermore, a summary of the experimental results compared with other high-efficiency articles is provided to validate the advantages of this method.

• Journal of Korean Society for Atmospheric Environment
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• v.28 no.4
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• pp.423-434
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• 2012

This study was carried out to develop for the emission factor of greenhouse gas (GHG) from medium and smallscaled incineration facility using RPF which is considering as a part of renewable energy in UNFCC. The actual concentration of the exhaust gas and the fuel composition of RPF were measured for the calculation of GHG emission factor in RPF incinerators, and were compared with the IPCC guideline. The $CO_2$ and $N_2O$ emission factors by the actual concentration of exhaust gas were $2.3575{\pm}1.0070tCO_2/tRPF$ and $0.0014{\pm}0.0014tN_2O/tRPF$ respectively. Also, $CO_2$ emission factor by the RPF composition was $2.7057{\pm}0.0540tCO_2/tRPF$. The GHG emission factor per energy by the actual concentration was $83.0867{\pm}26.0346tCO_2e/TJ$ which showed higher consistency with the GHG emission factor ($80.3967tCO_2e/TJ$) of waste plastic in the IPCC guideline (2006b). The $CO_2$ and $N_2O$ emission factor calculated in this study is considered as a meaningful data for GHG emission factor of RPF incineration facility because of not being developed in ROK.

• Journal of The Korean Association For Science Education
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• v.34 no.4
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• pp.407-415
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• 2014

Genetic determinism of human behaviors is considered as a philosophical perspective that genes in humans determine biological as well as social traits. However, many biologists agree that human traits are determined by interactions between genes and genes, as well as between genes and environments. In this context, genetic determinism still affect ideas of the general public as well as research directions of biologists. According to Cl$\acute{e}$ment's KVP model (Cast$\acute{e}$ra & Cl$\acute{e}$ment, 2012), teachers' conceptions of genetic determinism influence students' concepts of genetics. This study intends to investigate teachers' conceptions on genetic determinism of human behaviors. For this end, a questionnaire adopted from a previous research (Cast$\acute{e}$ra & Cl$\acute{e}$ment, 2012) has been administered to 308 teachers including 151 pre-service and 157 in-service. Factor analysis has been conducted to extract major factors and one-way ANOVA has been employed to find out differences in extracted factors among different groups of teachers. Four factors have been extracted from 14 items of questionnaire, including factor 1, a perspective of genetic determinism of gender differences in intellectual ability, social status, and emotional traits; factor 2, a perspective of genetic determinism of individual differences in intellectual ability; factor 3, a perspective of genetic determinism of individual differences in biological immune function and behavioral trait; and factor 4, a perspective of genetic determinism of ethnic differences. From the results of One-way ANOVA among teacher groups on four factors, first, it has shown a significant difference in factor 1 (F=3.325, p=.006), factor 3 (F=3.320, p=.006) and factor 4 (F=4.325, p=.001) due to their subject matters. In post-hoc comparison there have been no significant difference between biology teachers and other teachers. It has also been found that there was a significant difference between pre-service and in-service teachers in factor 1 (t=-3.938, p=.000) and factor 4 (t=-3.121, p=.002) and in-service teachers are more genetic deterministic than pre-service teachers. Finally, different religions have no influence on teachers' conceptions of genetic determinism of human behaviors.

• BMB Reports
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• v.45 no.4
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• pp.227-232
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• 2012

In vertebrates, there are two variants of eukaryotic peptide elongation factor 1A (eEF1A; formerly eEF-$1{\alpha}$), eEF1A1 and eEF1A2, which have three well-conserved domains ($D_I$, $D_{II}$, and $D_{III}$). In neurons, eEF1A1 is the embryonic type, which is expressed during embryonic development as well as the first two postnatal weeks. In the present study, EGFP-tagged eEF1A1 truncates were expressed in cortical neurons isolated from rat embryo (E18-19). Live cell images of transfected neurons showed that $D_{III}$-containing EGFP-fusion proteins (EGFP-$D_{III}$, -$D_{II-III}$, -$D_{I-III}$) formed clusters that were confined within somatodendritic domains, while $D_{III}$-missing ones (EGFP-$D_I$, -$D_{II}$, -$D_{I-II}$) and control EGFP were homogeneously dispersed throughout the neuron including axons. In dendrites, EGFP-$D_{III}$ was targeted to the heads of spine- and filopodia-like protrusions, where it was colocalized with $SynGAP{\alpha}$, a postsynaptic marker. Our data indicate that $D_{III}$ of eEF1A1 mediates formation of clusters and localization to spines.

• Information Systems Review
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• v.12 no.3
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• pp.19-48
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• 2010

This study focused on characterizing various factors in order for learners to maintain their interests in learning and to maximize learning effects as the top priority purpose of university e-Learning, on the basis of results of conceptual studies on existing e-Learning and practical studies, and then on examining them practically. It also analyzed which factors would have greater influence on learning effects of e-Learning in general. Moreover, in comparison with existing numerous studies which examined only factor such as learning effects of e-Learning, it analyzed such things in detail according to division into three items such as learning satisfaction, learning transfer and learning recommendation. To achieve such purposes of the study, it characterized and set 3 factors such as learning contents, instructional design and user convenience on the assumption that such factors have a significant influence on learning effects of e-Learning. Moreover, the factor of learning contents includes 3 detailed elements, i.e., learning issue and objective, knowledge information, and consistency and propriety, and the factor of instructional design includes 4 detailed elements, i.e., interest and sympathy, interaction, contents presentation and explanatory strategy. Lastly, the factor of user convenience includes 2 detailed elements such as screen configuration, and check-up of contents and teaching schedule. According to analytical results, it showed all 3 factors such as learning contents, instructional design and user convenience have a significant influence on learning effects of e-Learning(i.e., learning satisfaction, learning transfer and learning recommendation). In more detail, it showed the learning issue and objective from the factor of learning contents have the greatest influence on learning satisfaction of e-Learning. Then, it is the most important to set the learning issue and objective with given priority to learners and set the learning objective estimable, in order to raise the learning satisfaction. It showed the contents presentation from the factor of instructional design on the learning transfer. Therefore, it is the most important to structuralize mutual relation and presentation orders to promote learning systematically and to let learners access to such things, for the purpose of raising the learning transfer. Moreover, it showed the interest and sympathy from the factor of instructional design has the greatest influence on the learning recommendation. Thus, it is the most important to promote learners' interests to the maximum using well-timed media, and to give a lecture enough to arouse learners' sympathy.

• Asia pacific journal of information systems
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• v.23 no.4
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• pp.151-175
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• 2013

This study investigates the potential components for academic research collaboration, and the factors that make it possible to achieve higher academic productivity. The components include collaboration factors and a collaboration model. We use two major collaboration factors to develop a framework for understanding the mechanisms that influence academic research collaborations: motivational factors and mediating factors. Motivational factors include self-motivation and trust whereas mediating factors are collaboration orientation and peer support. We analyze the effect for use of e-collaboration with research performance, reward, and satisfaction with e-research output. A survey of academicians was conducted, and by using the factor analysis and the structural equation model with SPSS 20 AMOS, we illustrate the possible influence of these factors on research performance and satisfaction. We discovered that both motivational and mediating factors play important roles on the success of academic research. This study offers several implications for academicians. We develop a parsimonious research model, which is related to e-collaboration in academic research. This unique model offers academicians to achieve good publication output from the research team. The motivational factor, self-motivation and trust, are important factors which has received positive impact of mediating factor collaboration orientation and peer support. Our research sheds light on the crucial factors for use of e-collaboration which offer the ultimate effect on performance and satisfaction with e-research output. Satisfaction motivates people to work more and more on the field of their interest, thereby influencing the performance of academicians. Rewards should be distributed according to performance of the individual, which will motivate the person to become more enthusiastic for his work of interest. Our evidence suggests that in understating the collaborative process, one must account for the context in which the collaboration occurs, the motivation of the collaborators, the scope and nature of the project, the roles and activities undertaken, and interpersonal processes such as trust. Researchers' motivations for engaging in collaboration were both instrumental and intrinsic.

• Molecules and Cells
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• v.43 no.3
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• pp.264-275
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• 2020

Reactive oxygen species (ROS) play a significant role in intracellular signaling and regulation, particularly when they are maintained at physiologic levels. However, excess ROS can cause cell damage and induce cell death. We recently reported that eIF2α phosphorylation protects hepatocytes from oxidative stress and liver fibrosis induced by fructose metabolism. Here, we found that hepatocyte-specific eIF2α phosphorylation-deficient mice have significantly reduced expression of the epidermal growth factor receptor (EGFR) and altered EGFR-mediated signaling pathways. EGFR-mediated signaling pathways are important for cell proliferation, differentiation, and survival in many tissues and cell types. Therefore, we studied whether the reduced amount of EGFR is responsible for the eIF2α phosphorylation-deficient hepatocytes' vulnerability to oxidative stress. ROS such as hydrogen peroxide and superoxides induce both EGFR tyrosine phosphorylation and eIF2α phosphorylation. eIF2α phosphorylation-deficient primary hepatocytes, or EGFR knockdown cells, have decreased ROS scavenging ability compared to normal cells. Therefore, these cells are particularly susceptible to oxidative stress. However, overexpression of EGFR in these eIF2α phosphorylation-deficient primary hepatocytes increased ROS scavenging ability and alleviated ROS-mediated cell death. Therefore, we hypothesize that the reduced EGFR level in eIF2α phosphorylation-deficient hepatocytes is one of critical factors responsible for their susceptibility to oxidative stress.

• Microbiology and Biotechnology Letters
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• v.33 no.3
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• pp.184-188
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• 2005

IgE-dependent histamine-releasing factor (HRF) is found extracellularly to regulate the degranulation process of histamine in mast cells and basophils and known to play a predominant role in the pathogenesis of chronic allergic disease. HRF has been also identified in the intracellular region of the cell. Previously, we reported that HRF interacts with the 3rd cytoplasmic domain of the alpha subunit of Na,K ATPase and inhibits Na,K-ATPase activity. The predicated phosphorylation site in HRF by PKC was mapped to one serine residues (S98) by the computer analysis. In this study, we identified that S98 residue of HRF was phosphorylated using anti-HRFpS98 antibody which specifically recognizes the phosphorylated serine residue of HRF and HRFS98A mutant construct. We also performed $^{86}Rb^{+}-uptake$ assay to understand the role of HRF wild-type and HRFS98A mutants on the regulation of Na,K-ATPase activity. Dephosphorylation of HRF at serine 98 residue recovers slightly the inhibitory function of HRF, suggesting that phosphorylated HRF at serine 98 may not suppress the Na,K-hfpase activity.

• Proceedings of the KIPE Conference
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• 2004.07b
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• pp.528-532
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• 2004

Novel single-stage power factor correction AC/DC converter with low DC link voltage using new magnetic feedback technique is proposed in this paper. The Proposed converter has high power factor, tight output voltage regulation and low link capacitor voltage less than 450V for all the load range through the universal input line. This converter has also no dead-zone in the input current, which is seen in the conventional converter using the previous magnetic feedback technique. In this paper, the analysis of operations and features of the proposed converter is provided, and the experimental results of 90W-prototype shows the low harmonic distortions satisfied with EN 61000-3-2 Class D, high power factor and low link voltage less than 450V.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.2
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• pp.251-256
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• 2001

An error probability analysis is performed far a hybrid DS/SFH spread-spectrum system using minimum shift keying(MSK) modulation. The channel is assumed to be a Rayleigh fading channel with partial-band noise interference. Expressions are derived for the bit error rate(BER) in the context of Rician and Rayleigh fading channels, as a function of the average signal-to-noise ratio(SNR) $E_b/N_0$, the average signal-to- interference ratio(SJR) $E_b/N_J$, and channel parameters. As a result, in the fading channel with large Rician factor, K, which denotes the ratio of power of the direct and the diffused components, the partial-band interference is the worst case. On the other hand, in Rayleigh fading channel(K=0), the full-band interference($\rho$=1) brings the system to the worst case. Performance comparisons among various channels show that the factor K has much large effect on overall performance. For example, in conditions of $\rho$=0.1 and BER=$10^-2$, the system in Rician channel with K=10 requires more 1.9 dB SNR than that in AWGN channel, whereas it is less 5 dB SNR than that in the Rayleigh channel with K=0.