24,997 research outputs found
Iassus psudoulmi Kwon & Oh & Jung 2017, sp. nov.
No full textIassus psudoulmi sp. nov. Kwon et Jung (Figs. 15–21) Description. Head green. Vertex, pronotum and sculletum variegated with reddish brown spots. Pronotum dark brown with margins pale green. Scutellum pale brown with pale green spots posteriorly. Forewings translucent and pale green, with irregular dark spots and punctations; clavus with dark spot at apex of clavus. Legs green colored, without pattern or spot (Fig. 15). Male genitalia. Pygofer lobe process with ventral tooth near base, unbranched, apex curved; anal tube appendage short and blade-shaped (Fig. 16). Subgenital plate usually short, finger shaped with bent down apex, and without setae and bristles (Fig. 17). Aedeagus robust, apex with straight broadened lateral lobes, thickest at apex (Figs. 18–19). Measurements. Body length males 6.96–7.15 mm, females 6.47–7.15 mm. Specimens examined. Holotype: [CNU] ♂, Jichon-ri, Yanggang-myeon, Yeongdong-gun, Chungcheongbukdo, Korea, 18. VI. 2015, coll. S.M. Oh, Paratype: [CNU] 1♀, Chungnam National Univ., Yuseong-gu, Daejeon, Korea, 13. IV. 2014, coll. W.D. Lee; [CNU] 1♀, Sinbong-dong, Yuseong-gu, Daejeon, Korea, 23. V. 2015, coll. K.H. Kim; [CNU] 2♀♀, Jichon-ri, Yanggang-myeon, Yeongdong-gun, Chungcheongbuk-do, Korea, 17. VI. 2015, coll. S.A Kwon, light trap; [CNU] 2♂♂, 2♀♀, Jichon-ri, Yanggang-myeon, Yeongdong-gun, Chungcheongbuk-do, Korea, 18. VI. 2015, coll. S.M. Oh; [CNU] 1♀, Chungbuk National Univ., Seowon-gu, Cheongju-si, Chungcheongbuk-do, Korea, 21. VII. 2015, coll. E.J. Kim. Host plants. Unknown Distributions. Korea (Central)*. Remarks. This new species is similar to Iassus ulmi (Kusnezov, 1929), but differs as follows: 1) pygofer lobe process extended at posterior margin; 2) pygofer appendage small and unreachable at posterior margin. Etymology. The specific name is derived from the similar species Iassus ulmi (Kusnezov, 1929).Published as part of Kwon, Sua, Oh, Sumin & Jung, Sunghoon, 2017, A new species and two new records of the leafhopper genus Iassus Fabricius (Hemiptera: Auchenorrhyncha: Cicadellidae) from Korea, with a key to the Korean Iassus species in Zootaxa 4341 (1), DOI: 10.11646/zootaxa.4341.1.13, http://zenodo.org/record/103869
Impacts of glycans attached to therapeutic glycoproteins
No full textHigh value-added therapeutic proteins have been
leading the biologics industry and occupied major portion of
the market. More than 60% of the currently available protein
therapeutics are glycoproteins attached with glycans which
play crucial roles for the protein folding, therapeutic efficacy,
in vivo half-life and immunogenecity. This review
introduces the process of glycosylation and the impacts of
glycans in the aspects of therapeutics. The important glycan
structures in therapeutic performances were also summarized
focusing on three representative categories of glycoproteins,
cytokines, therapeutic antibody and enzyme. Currently,
mammalian expression systems such as Chinese hamster
ovary cells are preferred for the production of therapeutic
glycoproteins due to their ability to synthesize glycans
having similar structures with human type glycans. However,
recent advances of plant glycoengineering to overcome
the limitation originating from different glycan structures
will soon allow to develop more efficient and economic
plant-based production systems for therapeutic glycoproteins.open
EEG-based Emotion Classification using Bayesian Belief Networks in Pleasant and Unpleasant Odorant Stimuli
No full textIn this paper, we proposes an emotion classification method based on Bayesian Belief Networks (BBN) to classify
the EEG signals which are induced by the olfactory stimuli. In order to stimulate the olfactory organ, the citralva
is used as the pleasant smell and 2-melcaptoethanol is used as the unpleasant smell. We placed the 4-channel
EEG electrodes on F3, F4 at frontal lobe and T3, T4 at temporal lobe to acquire EEG signals in according to the
standard electrode placement, which is called international 10-20 system. The participants are five high school
students (4 male and 1 female) whose ages are from 17 to 18. To extract features from EEG signals, the timefrequency
analysis is performed by using the Event-Related Spectral Perturbation (ERSP). The average values of
relative power of the frequency in each time domain are used as the features for the BBN classifier. To evaluate
the performance of the proposed method, we compared the performance of the BBN and Naïve Bayesian
Networks (BN). As a result of the comparison, we confirm that the classification rate of the BBN is increased by
approximately 11%.1
7-DOF Horseback Riding Simulator based on a crank mechanism with variable radius and Its Inverse Kinematics Solution
No full textConstruction of an in vitro trans-sialylation system: surface display of Corynebacterium diphtheriae sialidase on Saccharomyces cerevisiae
No full textSialidases can be used to transfer sialic acids from sialoglycans to asialoglycoconjugates via the trans-glycosylation reaction mechanism. Some pathogenic bacteria decorate their surfaces with sialic acids which were often scavenged from host sialoglycoconjugates using their surface-localized enzymes. In this study, we constructed an in vitro trans-sialylation system by reconstructing the exogenous sialoglycoconjugate synthesis system of pathogens on the surfaces of yeast cells. The nanH gene encoding an extracellular sialidase of Corynebacterium diphtheriae was cloned into the yeast surface display vector pYD1 based on the Aga1p-Aga2p platform to immobilize the enzyme on the surface of the yeast Saccharomyces cerevisiae. The surface-displayed recombinant NanH protein was expressed as a fully active sialidase and also transferred sialic acids from pNP-α-sialoside, a sialic acid donor substrate, to human-type asialo-N-glycans. Moreover, this system was capable of attaching sialic acids to the glycans of asialofetuin via α(2,3)- or α(2,6)-linkage. The cell surface-expressed C. diphtheriae sialidase showed its potential as a useful whole cell biocatalyst for the transfer of sialic acid as well as the hydrolysis of N-glycans containing α(2,3)- and α(2,6)-linked sialic acids for glycoprotein remodeling.open
Passivity Mimicking Control for a XENMA Gait Rehabilitation Robot with Rimless Wheel Model
No full textStability analysis of time delay control systems
No full text학위논문(석사) - 한국과학기술원 : 기계공학전공, 2001.8, [ iv, 75 p. ]시간지연제어기법은 시간지연추정방법을 사용하는 강인 비선형 제어기법이다. 뿐만 아니라 이 제어기법은 단순한 구조를 지니고 있다. 실제 시스템에 시간지연제어기법을 적용하기 위해서 우리는 안정성을 보장하도록 시간지연제어기를 설계하여야만 한다. 기존의 시간지연제어시스템에 대한 안정하기 위한 충분조건은 시간지연이 무한히 작다라는 가정하에서 제시되었다. 그러나 실제로 시간지연이 무한히 작다라는 가정을 구현하는 것에는 한계가 있다. 그래서 이 연구에서는 한정된 시간지연을 갖는 실제경우의 시간지연제어시스템에 대한 새로운 안정하기 위한 충분조건을 제시한다. 그리고 모의실험결과로부터 시간지연이 충분히 작을지라도 기존의 안정하기 위한 충분조건을 만족시키더라도 시스템이 불안정한 응답을 보이는 경우가 있는데 이 연구에서 제시하는 새로운 안정하기 위한 충분조건을 만족시키는 경우에는 시스템이 항상 안정한 응답을 보임을 알 수 있다.한국과학기술원 : 기계공학전공
4D Electron Tomography
No full textTemporal Tomography
Tomography is a widely used technique for visualizing three-dimensional objects by algorithmic reconstruction from multiple two-dimensional images from distinct vantage points. However, its application has largely been restricted to static imaging.
Kwon and Zewail
(p.
1668
) have now adapted an ultrafast electron microscope to perform tomography with subpicosecond resolution. The method relies on systematically varying the tilt angle of the sample with respect to the incoming electron beam, and enabled assembly of a detailed frame-by-frame record of the response of a curled carbon nanotube to sudden heating.
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Identification and functional characterization of the NanH extracellular sialidase from Corynebacterium diphtheriae
No full textCorynebacterium diphtheriae, a pathogenic Gram-positive bacterium, contains sialic acids on its cell surface, but no genes related to sialic acid decoration or metabolism have been reported in C. diphtheriae. In the present study, we have identified a putative sialidase gene, nanH, from C. diphtheriae KCTC3075 and characterized its product for enzyme activity. Interestingly, the recombinant NanH protein was secreted as a catalytically active sialidase into the periplasmic space in Escherichia coli, while the short region at its C-terminus was truncated by proteolysis. We reconstructed a truncated NanH protein His6-NanHΔN devoid of its signal sequence as a mature enzyme fused with the 6xHis tag at the N-terminal region. The purified His6-NanHΔN can cleave α-2,3- and α-2,6-linked sialic acid from sialic acid-containing substrates. In addition, even though the efficiency was low, the recombinant His6-NanHΔN was able to catalyse the transfer of sialic acid using several sialoconjugates as donor, suggesting that the reversible nature of C. diphtheriae NanH can be used for the synthesis of sialyl oligosaccharides via transglycosylation reaction.open
Features and applications of bacterial sialidases
No full textSialidases, or neuraminidases (EC 3.2.1.18), belong to a class of glycosyl hydrolases that release terminal N-acylneuraminate residues from the glycans of glycoproteins, glycolipids, and polysaccharides. In bacteria, sialidases can be used to scavenge sialic acids as a nutrient from various sialylated substrates or to recognize sialic acids exposed on the surface of the host cell. Despite the fact that bacterial sialidases share many structural features, their biochemical properties, especially their linkage and substrate specificities, vary widely. Bacterial sialidases can catalyze the hydrolysis of terminal sialic acids linked by the α(2,3)-, α(2,6)-, or α(2,8)-linkage to a diverse range of substrates. In addition, some of these enzymes can catalyze the transfer of sialic acids from sialoglycans to asialoglycoconjugates via a transglycosylation reaction mechanism. Thus, some bacterial sialidases have been applied to synthesize complex sialyloligosaccharides through chemoenzymatic approaches and to analyze the glycan structure. In this review article, the biochemical features of bacterial sialidases and their potential applications in regioselective hydrolysis reactions as well as sialylation by transglycosylation for the synthesis of sialylated complex glycans are discussed.open
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