• Title/Summary/Keyword: Directed evolution

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Taxonomic Notes on the Genus Sinopoda (Araneae, Sparassidae), with Descriptions of Two New Species from Korea

  • Lee, Jun-Gi;Lee, Jun-Ho;Kim, Sam-Kyu
    • Animal Systematics, Evolution and Diversity
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    • v.32 no.4
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    • pp.281-292
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    • 2016
  • The genus Sinopoda (Araneae, Sparassidae) from Korea are taxonomically reviewed. As a result, Sinopoda aureola is removed from the synonymy of Sinopoda stellatops and treated as a valid species. In addition, two new species, Sinopoda biguttata sp. nov. and Sinopoda nigrobrunnea sp. nov. are described with accompanying photographs. The new species, S. biguttata sp. nov., can be distinguished from other congeners by the combination of following characteristics: a pair of large ivory patterns near posterior muscle sigilla on opisthosoma; relatively small internal genitalia and long, distally bifurcated fertilization duct. The new species, S. nigrobrunnea sp. nov., can be distinguished from other congeners by the combination of following characteristics: lateral edge of epigyne angled; edge of epigynal pocket linear; glandular appendages perpendicularly directed then curved posteriorly.

Application Prototyping to Support Learning from Online Lectures on Building Construction (건축시공 온라인강의 학습지원용 애플리케이션 프로토타이핑)

  • Kim, Seong-Bin;Jo, Min-Jin;Kim, Jae-Yeob
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2020.06a
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    • pp.38-39
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    • 2020
  • Currently, attempts are being made to introduce innovative teaching methods in architectural engineering education. However, there is still a lack of research supporting self-directed learners. In this regard, this study sought to develop an application prototype to support learning from online lectures on architectural engineering and conduct prototyping for its evolution. Menus in the application prototype consisted of four main categories: lecture operation, video lectures, eBooks and past exam questions. The lecture operation was classified into eight sub-categories, including assignment submission and notice, so as to support interactions between instructors and learners as well as confirmation of the delivery methods. With respect to video lectures, assignment submissions and notice functions, prototyping connecting the mobile web was implemented to enhance user convenience.

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Performance Analysis of Adaptive Channel Estimation Scheme in V2V Environments (V2V 환경에서 적응적 채널 추정 기법에 대한 성능 분석)

  • Lee, Jihye;Moon, Sangmi;Kwon, Soonho;Chu, Myeonghun;Bae, Sara;Kim, Hanjong;Kim, Cheolsung;Kim, Daejin;Hwang, Intae
    • Journal of the Institute of Electronics and Information Engineers
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    • v.54 no.8
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    • pp.26-33
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    • 2017
  • Vehicle communication can facilitate efficient coordination among vehicles on the road and enable future vehicular applications such as vehicle safety enhancement, infotainment, or even autonomous driving. In the $3^{rd}$ Generation Partnership Project (3GPP), many studies focus on long term evolution (LTE)-based vehicle communication. Because vehicle speed is high enough to cause severe channel distortion in vehicle-to-vehicle (V2V) environments. We can utilize channel estimation methods to approach a reliable vehicle communication systems. Conventional channel estimation schemes can be categorized as least-squares (LS), decision-directed channel estimation (DDCE), spectral temporal averaging (STA), and smoothing methods. In this study, we propose a smart channel estimation scheme in LTE-based V2V environments. The channel estimation scheme, based on an LTE uplink system, uses a demodulation reference signal (DMRS) as the pilot symbol. Unlike conventional channel estimation schemes, we propose an adaptive smoothing channel estimation scheme (ASCE) using quadratic smoothing (QS) of the pilot symbols, which estimates a channel with greater accuracy and adaptively estimates channels in data symbols. In simulation results, the proposed ASCE scheme shows improved overall performance in terms of the normalized mean square error (NMSE) and bit error rate (BER) relative to conventional schemes.

The 40~50Day Intraseasonal Oscillation of the Geostationary Meteorological Satellite High Cloud Amount (GMS 상층운량의 40~50일 계절만 진동)

  • 하경자;서애숙
    • Journal of Environmental Science International
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    • v.5 no.5
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    • pp.619-633
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    • 1996
  • Intraseasonal variability of the tropical convection over the Indian/western Pacific is studied using the Geostationary Meteorological Satellite high cloud amount. This study is directed to find the tropical-extratropical interaction in the frequency range of intraseasonal and interannual variabilities of the summer monsoon occured over the domain of 90E-171W and 495-50N. Especially, in order to investigate the intraseasonal interaction of last Asia summer monsoon associated with the tropical convections in the high cloud amounts, the spatial and time structure of the intraseasonal oscillation for the movement-and the evolution of the large-scale connections are studied. To describe the spatial and the time evolution, the extended empirical orthogonal function analysis is applied. The first mode may be considered to a normal structure, indicating that the strong convection band over 90E-120E is extended to sastward but this mode was detected as the intraseasonal variability during summer monsoon. It is found that the dominant intraseasonal mode of the tropical convection consists of the spatial changes over a broad period range centered around 40~50days.

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Professional Project and the Evolution of Non-Dominant Medicines;The Case of Osteopathy and Chiropractic

  • Kwon, Oh-Min;Ahn, Sang-Woo
    • Korean Journal of Oriental Medicine
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    • v.13 no.3
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    • pp.165-178
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    • 2007
  • This article explores how non-dominant medical practitioners shape their own self-images and the identity of relevant medicine and in what ways fashioning of self-images and accompanying modalities of medical practice informs the social evolution of the medicines at specific times and over specific places, by means of the historical configuration of osteopathy and chiropractic in the UK and the US. Attention is directed onto motivations and pursuits for professional recognition and actual strategies and activities of non-dominant medicines and its practitioners by turning to historical instances such as osteopathy and chiropractic in the UK and the US, not least drawing focus on professional desires with regard to circumstances it faces within and without. Some non-dominant medicines as a way with which to acquire and protect the exclusive monopoly of its knowledge and practical skills, adopted various forms of professionalism project, as dominant biomedical groups pressed up non-dominant medicines by virtue of marginalizing tactics. Meanwhile, non-dominant medicines took somewhat distinctive professionalisation strategies from each other. Strategies they took were diversified depending on medical philosophy, healing modality, the degree of occupational solidarity embodied as forms of medical organisation, and especially vocational aspiration and prospect. Change of socio-medical culture and the state's policy seems to have wielded critical influenceon the determination of the ups and downs of non-dominant medicines. From the perspective of long-term time span, dominant biomedicine eventually did not have much influence on the ups and downs of marginalized medicines in so far as in the case of osteopathy and chiropractic in Englandand the U. S.

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Potential Industrial Applications and Evolution of Carbohydrolases and Glycansucrases

  • Kim, Do-Man;Seo, Eun-Seong;Lee, Jin-Ha;Kang, Hee-Kyoung;Cho, Jae-Young
    • Proceedings of the Korean Society for Applied Microbiology Conference
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    • 2004.06a
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    • pp.215-218
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    • 2004
  • Dextrans make up a class of polysaccharides that are D-glucans of various structures with contiguous $\alpha$-1longrightarrow6 ~6 glycosidic linkages in the main chains and $\alpha$-1longrightarrow2, $\alpha$-1longrightarrow3, or $\alpha$-1longrightarrow4 branch glycosidic linkages, depending on the specificity of the particular dextransucrase. Glucansucrases that catalyze glucans synthesis from sucrose. When other carbohydrates, in addition to sucrose, are present in the enzyme digest, the enzyme transfers glucose to the carbohydrate acceptors in the secondary reaction that diverts some of the glucose from incorporation into glucan. Many carbohydrate acceptors have been recognized and the products that result are dependent on the particular enzyme and the structure of the particular acceptor. Because of these unique catalytic characteristics, various dextransucrases have many important industrial and medical uses. To improve the understanding of their action mode and extend their applications, this study describes mechanism of glucan synthesis and potential industrial uses of dextransucrases, and our recent findings on the structural, functional organization and directed evolution of the glucansucrases to offer for designing glucansucrases with improved properties.

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Relation Between Magnetization Easy Axis and Anisotropic Magnetoresistance in Permalloy Films (퍼멀로이 박막의 자화 용이축과 자기저항 변화와의 상관관계에 대한 연구)

  • Hwang, Tae-Jong;Ryu, Yeung-Shik;Kwon, Jin-Hyuk;Kim, Ki-Hyeon;Kim, Dong-Ho
    • Journal of the Korean Magnetics Society
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    • v.18 no.1
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    • pp.28-31
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    • 2008
  • We studied the effect of easy magnetization axis orientation with respect to the strip direction by measuring the magnetoresistance(MR), the magneto-optic Kerr effect(MOKE), and real-time domain evolution. The five strips were patterned on a single chip with the easy axis orientation of each strip relative to the longitudinal direction by around $0^{\circ}$, $18^{\circ}$, $36^{\circ}$, $54^{\circ}$ and $72^{\circ}$, respectively. The overall shape of field dependent MR was mostly governed by the anisotropy magnetoresistnace. The relative change of the longitudinal MR was significantly increased with increasing angle between the easy axis and strip direction, whereas, the transverse MR variation rate was decreased with increasing angle. Several MR steps were observed during the magnetization reversal, and the simultaneous measurement of the MOKE and the domain images identified that the MR steps were associated with evolution of the oppositely directed magnetic domain.

Recent Trend in Bioscavengers for Inactivation of Toxic Organophosphorus Compounds (유기인 계열 독성물질 분해를 위한 바이오스캐빈저 최신 연구 동향)

  • Kim, Heejeong;Jeong, Keunhong;Kye, Young-Sik
    • Applied Chemistry for Engineering
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    • v.31 no.2
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    • pp.125-137
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    • 2020
  • In recent years, toxic organophosphorus compounds (OPs) have been used for civilians, becoming a great threat to the world. Alternative to the current treatment policy unpredictable for any prevention, researches on bioscavenger as an improved treatment have been actively conducted. Bioscavengers refer to proteins and enzymes that prevent intoxication by inactivating or binding toxic OPs before they reaches the target. In particular, extensive efforts have been made to develop catalytic bioscavengers that quickly detoxify OPs even with a small dose of the protein by performing multiple binding and hydrolysis processes with OPs. This review introduces the latest studies and results for developing catalytic bioscavengers using molecular evolution and protein engineering techniques. We will briefly present some of the remaining challenges on developing enzymes into clinically approved drugs.

Increased mRNA Stability and Expression Level of Croceibacter atlanticus Lipase Gene Developed through Molecular Evolution Process

  • Jeong, Han Byeol;Kim, Hyung Kwoun
    • Journal of Microbiology and Biotechnology
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    • v.31 no.6
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    • pp.882-889
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    • 2021
  • In order to use an enzyme industrially, it is necessary to increase the activity of the enzyme and optimize the reaction characteristics through molecular evolution techniques. We used the error-prone PCR method to improve the reaction characteristics of LipCA lipase discovered in Antarctic Croceibacter atlanticus. Recombinant Escherichia coli colonies showing large halo zones were selected in tributyrin-containing medium. The lipase activity of one mutant strain (M3-1) was significantly increased, compared to the wild-type (WT) strain. M3-1 strain produced about three times more lipase enzyme than did WT strain. After confirming the nucleotide sequence of the M3-1 gene to be different from that of the WT gene by four bases (73, 381, 756, and 822), the secondary structures of WT and M3-1 mRNA were predicted and compared by RNAfold web program. Compared to the mean free energy (MFE) of WT mRNA, that of M3-1 mRNA was lowered by 4.4 kcal/mol, and the MFE value was significantly lowered by mutations of bases 73 and 756. Site-directed mutagenesis was performed to find out which of the four base mutations actually affected the enzyme expression level. Among them, one mutant enzyme production decreased as WT enzyme production when the base 73 was changed (T→ C). These results show that one base change at position 73 can significantly affect protein expression level, and demonstrate that changing the mRNA sequence can increase the stability of mRNA, and can increase the production of foreign protein in E. coli.

Hardness and Microstructure evolution of SUS630 Stainless steel Fabricated by Directed Energy Deposition (Direct energy deposition 공정으로 제조된 SUS630 스테인리스강 적층조형체의 경도 및 미세조직 연구)

  • Back, Seong Eun;Noh, Kyung-Ho;Park, Jin Yong;Cho, Yong Ju;Kim, Jeoung Han
    • Journal of Powder Materials
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    • v.25 no.3
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    • pp.220-225
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    • 2018
  • The microstructure and mechanical characteristics of SUS630 specimens fabricated using the direct energy deposition (DED) process are investigated. In DED, several process parameters such as laser scan speed, chamber gas flow, powder carrier gas flow, and powder feed rate are kept fixed; the laser power is changed as 150 W, 180 W, and 210 W. As the laser power increases, the surface becomes smooth, the thickness uniformity improves, and the size and number of pores decreases. With the increase in laser power, the hardness deviation decreases and the average hardness increases. The microstructure of the material is columnar; pores are formed preferentially along the columnar interface. The lath-martensite phase governs the overall microstructure. The volumetric fraction of the retained austenite phase is measured to increase with the increase of laser input power.