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Chemical Modification of Chitosan as Gene Carriers In Vitro and In Vivo

  • Kim, Tae-Hee;Jin, Hua;Kim, Hyun-Woo;Cho, Myung-Haing;Nah, Jae-Woon;Cho, Chong-Su
    • Proceedings of the Polymer Society of Korea Conference
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    • 2006.10a
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    • pp.178-178
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    • 2006
  • Chitosan has been investigated as a non-viral vector because it has several advantages such as biocompatibility, biodegradability and low toxicity with high cationic potential. However, low specificity and low transfection efficiency of chitosan as a DNA carrier need to be overcome for clinical trials. In this study, chemical modification for enhancement of cell specificity and transfection efficiency was investigated. Also, the chitosan derivative formulations in vivo were included.

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A Case study on the construction badness for slope reinforcement (사면보강공법 시공불량사례 검토를 통한 개선방안 연구)

  • Kwon, Sung-Ju;Kim, Yong-Soo;Chang, Bum-Soo;Nah, Kwang-Hee
    • Proceedings of the Korean Geotechical Society Conference
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    • 2005.03a
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    • pp.739-744
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    • 2005
  • The construction road work are increasing now. And the domestic slope construction are steadily increased and changed the complicated and large-scale. Therefore ground reinforcement for slope stabilization has been increasingly used during the past few decades with a wide variety of techniques including soil nailing, rock bolt, anchor and different types. But in some cases which applied slope reinforcement construction by badness or mistake. So this paper is the study of construction badness for slope reinforcement.

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Theoretical Evaluation of Degradation in Superconducting Multistrands for AC Use (교류용초전도연선의 교류전류열화현상의 이론적 검토)

  • Oh, Bong-Hwan;Nah, Wan-Soo;Oh, Sang-Soo;Ryu, Kang-Sik
    • Proceedings of the KIEE Conference
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    • 1993.11a
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    • pp.76-78
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    • 1993
  • When an alternating current is supplied to a super-conducting multi-stranded cable, the quench current value of the cable was observed to be less than the simple summation of individual quench current value of each strand. One of the causes for such a degradation was attributed to the nonuniform of the current distribution in multi-stranded cable due to magnetic mutual coupling among the strands. The degradation of the superconducting cable is evaluated theoretically by taking into account the magnetic coupling among the strands.

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Steam Turbine Technology for Advanced Steam Condition (증기조건 향상에 따른 증기터빈 기술 동향)

  • Nah, U.H.;Cho, S.I.;Shin, H.;Kim, Y.S.;Yang, S.H.
    • Proceedings of the KSME Conference
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    • 2003.04a
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    • pp.2174-2179
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    • 2003
  • For many years, T/G Supplier has constructed a number of thermal power plants and researched to improve the performance and the reliability of steam turbine, which are achieved by advances in design and materials technology. In recent, interest is renewed in advanced steam condition as means of improving economy of thermal power plant and reducing environmental pollution. Improvements in the maximum power have been driven by the development of advanced rotor and bucket material and longer last stage bucket. Improvements in efficiency have been brought through advances in mechanical efficiency and thermodynamic efficiency. This paper describes a number of new steam path design features introduced to the steam turbine product. And also this paper describes new design technologies' development, new technologies' trend and technologies' development for ultra-super critical steam turbine.

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Measurement of Multi-Port S-Parameters using Four-Port Network Analyzer

  • Kim, Jongmin;Luong, Duc Long;Nah, Wansoo;Kim, SoYoung
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.13 no.6
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    • pp.589-593
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    • 2013
  • An efficient measurement methodology is proposed to construct the scattering parameters of a multi-port device using a four-port vector network analyzer (VNA) without the external un-terminated ports. By using the four-port VNA, the reflected waves from the un-terminated ports could be minimized. The proposed method significantly enhances the accuracy of the S-parameters with less number of measurements compared to the results of classical renormalization technique which uses two-port VNA. The proposed method is validated from the measured data with the coupled 8-port micro-strip lines.

HEV: A Review (하이브리드 전기 자동차(HEV) 기술동향)

  • Nah, Do-Baek;Shin, Hyo-Soon
    • Journal of Energy Engineering
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    • v.19 no.1
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    • pp.39-50
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    • 2010
  • Hybrid Electric Vehicle(HEV) and Plug-in Hybrid Electric Vehicle(PHEV) will replace Conventional Gasolene Engine Vehicle at a rapid rate to eliminate emission gases and improve fuel economy. This review describes Fuzzy Logic Control strategy and Optimization for Parallel Hybrid Electric Vehicle. Recent progress on Electric Motor and Li-ion Battery for HEV and PHEV are given. Analysis on competitiveness of Korean HEV and PHEV technology based on the number of papers published and patents registered are also performed.

The Listen-in Technique for Blind Signals (블라인드 신호 감청기술)

  • Nah, Sun-Phil;Park, Cheol-Sun;Jang, Won
    • Journal of the Korea Institute of Military Science and Technology
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    • v.8 no.4 s.23
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    • pp.102-109
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    • 2005
  • In this paper, we propose a new listen-in technique to overcome the problems and the shortcomings which could possibly meet in the previous listen-in methods to deal with the blind signal manually according to operator's decision. In the proposed listen-in method, receiving the signals, classifying the modulation types, and demodulating the signals can be done automatically without operator's intervention. We realize the listen-in technology by developing the high speed frequency tuner, the automatic modulation recognizer, and the signal demodulator. In conclusion, we confirm and show that the developed equipment has a good performance in classifying the modulation type through the computer simulation and the field test.

Autophagy in Neurodegenerative Diseases: From Mechanism to Therapeutic Approach

  • Nah, Jihoon;Yuan, Junying;Jung, Yong-Keun
    • Molecules and Cells
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    • v.38 no.5
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    • pp.381-389
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    • 2015
  • Autophagy is a lysosome-dependent intracellular degradation process that allows recycling of cytoplasmic constituents into bioenergetic and biosynthetic materials for maintenance of homeostasis. Since the function of autophagy is particularly important in various stress conditions, perturbation of autophagy can lead to cellular dysfunction and diseases. Accumulation of abnormal protein aggregates, a common cause of neurodegenerative diseases, can be reduced through autophagic degradation. Recent studies have revealed defects in autophagy in most cases of neurodegenerative disorders. Moreover, deregulated excessive autophagy can also cause neurodegeneration. Thus, healthy activation of autophagy is essential for therapeutic approaches in neurodegenerative diseases and many autophagy-regulating compounds are under development for therapeutic purposes. This review describes the overall role of autophagy in neurodegeneration, focusing on various therapeutic strategies for modulating specific stages of autophagy and on the current status of drug development.

Computer Science Education and Use of Learning Materials (비전공자 컴퓨터교육과 학습보조 자료의 활용)

  • Nah, Jeong Eun
    • Journal of Engineering Education Research
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    • v.22 no.6
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    • pp.21-27
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    • 2019
  • In the last few years, interest in computer science education has increased significantly. The curriculum is being revised to introduce computer science. Although interest has focused on coding as the main subject, in fact the computer science includes much more than coding. It engages people in being creative with technology as well as understanding the fundamental principles of computer science. Therefore, it is important to consider the curriculum to provide a foundation by teaching and learning computer science. The curriculum is required the development of courses to teach computer science for non-majors in general education. To think like a computer scientist on the knowledge of computer science is computational thinking. In order to maximize the effectiveness of teaching and learning for computational thinking, various teaching methods and supplementary learning materials, and activities should be developed and provided.

The value of panoramic radiography in assessing maxillary sinus inflammation

  • Cho, Bong-Rae;Jung, Yun-Hoa;Nah, Kyung-Soo
    • Imaging Science in Dentistry
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    • v.38 no.4
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    • pp.215-218
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    • 2008
  • Purpose : To evaluate the value of panoramic radiography in diagnosing maxillary sinus inflammation. Materials and Methods : A total of 214 maxillary sinuses from 114 panoramic radiographs were assessed in this study. Two independent experienced oral radiologists evaluated the images in random order for sinus inflammation. Using Cone beam CT images as the gold standard, the sensitivity and specificity of panoramic radiography were calculated, and inter- and intraobserver agreement for panoramic interpretation were obtained. Results : The mean sensitivity and specificity of panoramic radiography were 81.0% and 85.6%, respectively. The weighted kappas for inter- and intraobserver agreement of panoramic radiography were 0.56 and 0.60, respectively. Conclusion : Panoramic radiography is a reasonably accurate method for diagnosing maxillary sinus inflammation and can be used for screening. However, additional examinations should be considered in patients with potentially significant pathology. (Korean J Oral Maxillofac Radiol 2008; 38: 215-8)

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