• 제목/요약/키워드: Asymmetric division

검색결과 213건 처리시간 0.026초

Control of asymmetric cell division in early C. elegans embryogenesis: teaming-up translational repression and protein degradation

  • Hwang, Sue-Yun;Rose, Lesilee S.
    • BMB Reports
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    • 제43권2호
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    • pp.69-78
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    • 2010
  • Asymmetric cell division is a fundamental mechanism for the generation of body axes and cell diversity during early embryogenesis in many organisms. During intrinsically asymmetric divisions, an axis of polarity is established within the cell and the division plane is oriented to ensure the differential segregation of developmental determinants to the daughter cells. Studies in the nematode Caenorhabditis elegans have contributed greatly to our understanding of the regulatory mechanisms underlying cell polarity and asymmetric division. However, much remains to be elucidated about the molecular machinery controlling the spatiotemporal distribution of key components. In this review we discuss recent findings that reveal intricate interactions between translational control and targeted proteolysis. These two mechanisms of regulation serve to carefully modulate protein levels and reinforce asymmetries, or to eliminate proteins from certain cells.

대칭 및 비대칭 2차원 쐐기의 입수 충격에 관한 실험적 연구 (Experimental Study of Water Impact Loads on Symmetric and Asymmetric Wedges)

  • 김경환;이동엽;홍사영;김영식;김병완
    • 한국해양공학회지
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    • 제28권3호
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    • pp.209-217
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    • 2014
  • In the present study, the water impact loads on two-dimensional symmetric and asymmetric wedges were mainly studied. The impact pressure and force were measured during a vertical drop of the symmetric and asymmetric wedges. The measured pressure was compared with analytic solutions. The measured force at a local area of the wedge was compared with the integrated pressures and analytic solutions. Some findings on symmetric and asymmetrical wedge drops are presented, and the reliability of the force sensor used for the measurement of the local impact force is discussed.

Asymmetric Polymerase Chain Reaction-Single-Strand Conformation Polymorphism (Asymmetric PCR-SSCP) as a Simple Method for Allele Typing of HLA-DRB

  • Kang, Joo-Hyun;Kim, Kyeong-Hee;Maeng, Cheol-Young;Kim, Kil-Lyong
    • BMB Reports
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    • 제32권6호
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    • pp.529-534
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    • 1999
  • Asymmetric PCR and single-strand conformation polymorphism (SSCP) methods were combined to analyze human leukocyte antigen (HLA)-DRB allele polymorphism. Asymmetric PCR amplification was applied to generate single-stranded DNA (ssDNA) using the nonradioactive oligonucleotide primers desinged for the polymorphic exon 2 region. The conformational differences of ssDNAs, depending on the allele type, were analyzed by nondenaturing polyacrylamide gel electrophoresis and visualized by ethidium bromide staining. The ssDNAs were clearly separated from double-stranded DNA without interference and obviously migrated depending on their allele type. This method was applied to the genomic DNA either from homozygous or from heterozygous cell lines containing the DR4 allele as template DNA using DR4-specific primers, and satisfying results were obtained. Compared to the standard PCR-SSCP method, this asymmetric PCR-SSCP method has advantages of increased speed, reproducibility, and convenience. Along with PCR-SSP or sequence-based typing, this method will be useful in routine typing of HLA-DRB allele.

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비대칭 이중층 셔플넷 토폴로지를 이용한 파장분할다중화 링 (Wavelength Division Mutiplexing Ring using Asymmetric Bilayered ShuffleNet)

  • 지윤규
    • 대한전자공학회논문지SD
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    • 제41권5호
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    • pp.1-7
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    • 2004
  • 규칙적인 논리적 연결방법을 이용하면 노드에서 라우팅을 위한 프로세싱 시간이 단축되므로 고속의 네트워크에 적용이 가능하다. 규칙적인 논리적 연결방법의 하나인 셔플넷은 일반적으로 p개의 직접 연결이 다른 노드들과 이루어진다. 그러나 우리가 제안한 비대칭 이중층 셔플넷 토폴로지를 이용하면 2p개의 노드들과 직접 연결되므로 더욱 용량이 증대된 파장분할방식 링을 설계할 수 있다. 이 비대칭 이중층 셔플넷 토폴로지를 이용하여 파장분할방식 링에 파장을 할당하는 방법을 본 논문에서 연구하였다. 필요한 파장수를 최소화하는 것을 목표로 네트워크를 최적화하였다.

비대칭 활성화 확산 이론을 이용한 휴대폰 메뉴 구조 디자인 (Menu Structure Design using Asymmetric Spreading Activation in Mobile Phone)

  • 오세응;명노해
    • 대한인간공학회지
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    • 제28권1호
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    • pp.1-7
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    • 2009
  • As products are getting more diverse and new products are entering the market faster, customers have trouble learning how to use them. User-oriented menu structures may solve this problem. In order to design user-oriented menu structures, spreading activation theory has been studied. The spreading activation test shows that the strong associative relationship between words has shorter response times. Based on the spreading activation test, asymmetric spreading activation was introduced and a hypothesis that in a well-designed menu structure, association between upper-low menu pairs is not affected by an activation direction was tested for this study. In this study the menu of a cellular phone (Model: SPH-w2900) was extracted, and underwent 1st spreading activation tests. Then, on each menu pair, response time differences (asymmetric transition) by accuracy and directions were analyzed to find out problems in labels and improve menu structures and vocabulary. Second spreading activation tests were conducted to check whether asymmetric transitions decreased. The results showed that response time differences (asymmetric transition) for activation directions were found to be dropped significantly. Asymmetric transitions in spreading activation presented in this study will be helpful to define user-oriented menu structures.

Bimodal 방법을 이용한 하전입자 응집 모델링 (Development of Simple Bimodal Model for Charged Particle Coagulation)

  • 김상복;송동근;홍원석;신완호
    • 한국입자에어로졸학회지
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    • 제10권1호
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    • pp.27-31
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    • 2014
  • A simple bimodal model has been developed to analyze charged particle coagulation by modifying previously suggested bimdal model for evolution of particle generation and growth. In the present model, two monodisperse modes are used and 40 charge nodes are assigned to each mode to account both change of the particle size and charge distribution. In addition, we also implemented the effect of electrostatic dispersion loss in the present model. Based on the developed model, we analyzed coagulation of asymmetric bipolar charged particles by computing evolutions of particle number concentration, geometric mean diameter of particles, charge asymmetric ratio and geometric standard deviation of particle size distribution for various initial charge asymmetric ratios. The number concentration of asymmetric bipolar charged particles decreases faster than that of neutral particles but that does not give faster growth of particles since the electrostatic dispersion loss overwhelms particle growth by coagulation.

Optimal Design of a Two-phase BLDC Motor Considering Efficiency and Torque Ripple

  • Kim, Jae-Beom;You, Yong-Min;Kang, Sun-Il;Kwon, Byung-Il
    • Journal of Electrical Engineering and Technology
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    • 제8권5호
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    • pp.1131-1137
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    • 2013
  • This paper introduces novel a two-phase permanent magnet BLDC (PMBLDC) motor with both an asymmetric tooth and an auxiliary tooth in order to improve the dead point, efficiency and torque ripple. To calculate the merits of introducing each of the asymmetric tooth and the auxiliary tooth, characteristic analysis is performed respectively using finite element method (FEM). To maximize performance, we propose a novel model which combines the asymmetric tooth and the auxiliary tooth. To maximize the efficiency of the novel model, an optimal design is processed using the Kriging method and a genetic algorithm. Finally, an experiment is used to confirm the initial and optimal design results.

Highly Enantioselective Rh-catalyzed Transfer Hydrogenation of α-Functionalized Arylketones

  • Lee, Do-Min;Kwak, Se-Hun;Lee, Kee-In
    • Bulletin of the Korean Chemical Society
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    • 제30권6호
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    • pp.1317-1324
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    • 2009
  • Asymmetric transfer hydrogenation of α-functionalized arylketones has been studied. The chiral Rh-catalyst effectively performed in transfer hydrogenation of $\alpha$-mesyloxyketones with an azeotropic mixture of formic acid/triethylamine to produce optically active 1-arylethandiols with excellent enantioselectivity.

양식넙치 산지-도매가격간 비대칭적 가격전이 분석 (Asymmetric Transmission between Producer and Wholesale Prices in Farmed Olive Flounder Market)

  • 이헌동;마창모
    • 수산경영론집
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    • 제51권4호
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    • pp.69-83
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    • 2020
  • The purpose of this paper is to empirically investigate whether asymmetric price transmission exists in the distribution stage of farmed olive flounder market. For the analysis, time series data were used for the producer prices of Jeju and Wando, and the wholesale prices of Incheon, Hanam and Busan. Through the Granger causality test, the causal relationship from the producer price to the wholesale price was derived and the asymmetric price transmission was analyzed using the autoregressive distributed lag model (ARDL). As a result of the analysis, it was found that there is a phenomenon of 'positive asymmetric price transmission' from the producer price to the wholesale price. This result can be one evidence that excess profits are received in the intermediate distribution stage, and can be said to be a result showing the incompleteness and inefficiency of the distribution structure of the farmed olive flounder. In the future, it is required to establish an information-sharing system in all stages of production, distribution, and consumption that can create a competitive environment for distribution participants and resolve information asymmetry. Also, it is necessary to review the distribution center specializing in live fish from the viewpoint of the establishment of new distribution channels and sales diversification strategy under the rapidly changing fisheries environment.