• 제목/요약/키워드: Molecular Polarity

검색결과 82건 처리시간 0.028초

Electro-optical devices from polymer-stabilized liquid crystals with molecular shape polarity

  • Kim, Sang-Hwa;Chien, Liang Chy;Komitov, Lachezar
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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    • pp.839-842
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    • 2004
  • We present a fast-switching electro-optical device based on flexoelectro-optic effect in short pitch cholesterics oriented in uniform lying helix texture. The device has two operating modes: amplitude and phase modulation mode. The amplitude modulation mode is a fast in-plane switching of the device optic axis that enables to achieve a high percent of modulation of the transmitted light intensity whereas the phase mode gives a continuous change of the refractive index and thus of the phase shift of the transmitted light. By using a small concentration of diacrylate monomer and selecting the illumination conditions we have been able to create a inhomogeneous polymeric network mostly localized at both substrate surfaces and stabilize the two switching modes.

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IPS-LCD의 전압-투과율 히스테리시스법을 이용한 잔류 DC 전압 특성 (Residual DC Voltage Property in the In-plane Switching Cell Using the Voltage-transmittance Hysteresis Method)

  • 김향율;서대식;김재형
    • 한국전기전자재료학회논문지
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    • 제14권6호
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    • pp.487-490
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    • 2001
  • Residual DC voltage of the in-plane switching (IPS)-liquid crystal display(LCD) by voltage-transmittance (V-T) hysteresis method was studied. Several IPS-LCD which have different concentrations of cynao LCs and different resistivities of fluorine LCs were fabricated. We found that the residual DC voltage of the IPS-LCD was decreasing with increasing concentration of cyano LCs and increasing with decreasing specific resistivity of fluorine LC materials. The residual DC voltage property can be improved by low molecular weight and high polarity of cyano LC.

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Membrane Proteins Involved in Epithelial-Mesenchymal Transition and Tumor Invasion: Studies on TMPRSS4 and TM4SF5

  • Kim, Semi;Lee, Jung Weon
    • Genomics & Informatics
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    • 제12권1호
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    • pp.12-20
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    • 2014
  • The epithelial-mesenchymal transition (EMT) is one mechanism by which cells with mesenchymal features can be generated and is a fundamental event in morphogenesis. Recently, invasion and metastasis of cancer cells from the primary tumor are now thought to be initiated by the developmental process termed the EMT, whereby epithelial cells lose cell polarity and cell-cell interactions, and gain mesenchymal phenotypes with increased migratory and invasive properties. The EMT is believed to be an important step in metastasis and is implicated in cancer progression, although the influence of the EMT in clinical specimens has been debated. This review presents the recent results of two cell surface proteins, the functions and underlying mechanisms of which have recently begun to be demonstrated, as novel regulators of the molecular networks that induce the EMT and cancer progression.

물-수증기 계면을 통한 전기방전에 의한 수소 제조 (Hydrogen Generation by Electrical Discharge across Water-Vapor Interface)

  • 강구진;이수창;최용만;이웅무
    • 한국수소및신에너지학회논문집
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    • 제8권4호
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    • pp.155-160
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    • 1997
  • Generation of hydrogen and oxygen gas from water is mostly accomplished by electrolysis. In this report, a scheme is presented regarding the gas generation based on plasmolysis. Unlike electrolysis water dissociation by electrical discharge (plasmolysis) requires a high voltage to cause either electron emission or electron capture, and subsequent ionization of involved molecular species. When electrical discharge is initiated between electrodes separated by water-vapor interface, a very large electric field(~100kV/cm) is developed at the tip of the electrode placed in the vapor phase. It is found that the efficiency of plasmolysis depends on the polarity of the electrode placed in the vapor phase. Also presented is the scheme of hydrogen and oxygen generation by such electrical discharge.

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Expression of a set of glial cell-specific markers in the Drosophila embryonic central nervous system

  • Ahn, Hui Jeong;Jeon, Sang-Hak;Kim, Sang Hee
    • BMB Reports
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    • 제47권6호
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    • pp.354-359
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    • 2014
  • The types of glia in the central nervous system (CNS) of the Drosophila embryo include longitudinal glia (LG), cell body glia (CBG), and peripheral glia (PG). Transcription factors, such as glial cell missing and reverse polarity, are well-established general glial cell markers. Only a few glial cell-specific markers have been identified in the Drosophila embryonic CNS, thus far. In the present study, we employed the glial cell-specific markers for LG (vir-1/CG5453 and CG31235), CBG (fabp/CG6783 and CG11902), and PG (CG2310 and moody/CG4322), and comprehensively analyzed their expression patterns, during the embryonic CNS development. Our study validated the specificity of a set of glial markers, and further revealed their spatio-temporal expression patterns, which will aid in the understanding of the developmental lineage, and investigating their role in the development and homeostasis of the Drosophila CNS in vivo.

Gamma (${\gamma}$) Tubulin Reorganization during Bovine Fertilization and Parthenogenesis

  • Yung, Youn-Ji;Shin, Mi-Ra;Lee, Hwa-Young;Park, Sang-Hyun;Cui, Xiang-Sun;Kim, Nam-Hyung
    • 한국동물번식학회:학술대회논문집
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    • 한국동물번식학회 2002년도 춘계학술발표대회 발표논문초록집
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    • pp.49-49
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    • 2002
  • γ - tubulin is an essential, invariant constitutive centrosomal protein, which plays key roles in microtubule patterning and defining the microtubule intrinsic polarity. Although γ-tubulin was also present in cattle oocytes and zygotes, no details have been provided on its recruitment and localization to date. In this study, we determined γ-tubulin distribution chronologically in conjunction with microtubule dynamics during fertilization and parthenogenesis, with a view to understanding the molecular basis of zygotic centrosome reconstitution in cattle. (omitted)

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러빙된 폴리이미드 층에서의 전압-투과율 히스테리시스법 이용한 IPS-LCD의 잔류 DC 전압 특성에 관한 연구 (A Study on Residual DC in the IPS-LCD by Voltage-Transmittance Hysteresis Method on a Rubbed Polyimide Layer)

  • 이윤건;황정연;서대식;김향율;김재형
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2001년도 하계학술대회 논문집
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    • pp.656-659
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    • 2001
  • We investigated the residual DC in the in-plane switching (IPS)-liquid crystal display(LCD) by voltage-transmittance (V-T) hysteresis method. Several IPS-LCD which have different concentrations of cynao LCs and different resistivities of fluorine LCs were fabricated. We found that the residual DC voltage of the IPS-LCD was decreasing with increasing concentration of cyano LCs and increasing with decreasing specific resistivity of fluorine LC materials. The residual DC voltage property can be improved by low molecular weight and high polarity of cyano LC.

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Theoretical Study on the Conformations of Homooxacalix[4]arenes

  • Ham, Si-Hyun
    • Bulletin of the Korean Chemical Society
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    • 제25권12호
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    • pp.1911-1916
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    • 2004
  • The conformational preference of tetrahomodioxacalix[4]arenes with three different para substituents on the phenolic ring has been investigated by using ab initio molecular orbital theory (RHF/6-31$G^{\ast}$) and density functional theory (B3LYP/6-31$G^{\ast}$). The stability order is predicted to be cone > C-1,2-alternate > partial cone > 1,3-alternate > COC-1,2-alternate. The distorted cone conformation is found to be most stable in a gas phase and the calculated results are in agreement with the reported $^1$H NMR and X-ray experimental observations. The substitution of methylene with dimethyleneoxa bridges increases the size of the annulus of the molecule, its conformational mobility, and the number of hydrogen bonding patterns. The thermodynamic stability and the conformational characteristics of tetrahomodioxacalix[4]arenes are discussed in regards of the number of phenolic hydrogen bonding patterns and the polarity of a molecule. The substituent effects on the para position of the phenolic ring are also introduced.

The history and regulatory mechanism of the Hippo pathway

  • Kim, Wantae;Jho, Eek-hoon
    • BMB Reports
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    • 제51권3호
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    • pp.106-118
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    • 2018
  • How the organ size is adjusted to the proper size during development and how organs know that they reach the original size during regeneration remain long-standing questions. Based on studies using multiple model organisms and approaches for over 20 years, a consensus has been established that the Hippo pathway plays crucial roles in controlling organ size and maintaining tissue homeostasis. Given the significance of these processes, the dysregulation of the Hippo pathway has also implicated various diseases, such as tissue degeneration and cancer. By regulating the downstream transcriptional coactivators YAP and TAZ, the Hippo pathway coordinates cell proliferation and apoptosis in response to a variety of signals including cell contact inhibition, polarity, mechanical sensation and soluble factors. Since the core components and their functions of the Hippo pathway are evolutionarily conserved, this pathway serves as a global regulator of organ size control. Therefore, further investigation of the regulatory mechanisms will provide physiological insights to better understand tissue homeostasis. In this review, the historical developments and current understandings of the regulatory mechanism of Hippo signaling pathway are discussed.

아크릴산 단량체와 아지리딘 경화제 함량에 따른 점착제의 점착물성 변화 (Adhesive Property Changes Associated with the Content of Acrylic Acid Monomer and Aziridine Crosslinking Agent)

  • 최환석;황효연;정선경;이승구;이기윤
    • 폴리머
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    • 제36권1호
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    • pp.29-33
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    • 2012
  • 관능성 단량체로서 acrylic acid(AA)를 사용하였고, 기본 단량체로서는 2-ethylhexyl acrylate(2-EHA)를 사용하여 용액중합의 방법으로 점착제를 합성하였다. 점착제의 점착물성 중에 AA와 경화제 함량에 따른 점착제의 표면에너지와 물성변화 연구를 조사하였다. 합성된 점착제의 구조는 FTIR을 통하여 확인하였고 점도와 분자량은 Brookfield 점도계와 GPC를 사용하여 각각 측정하였다. 분자량과 점도는 AA가 6 wt%까지는 함량증가에 따라 증가하였으며 6 wt% 이상에서는 감소하였다. 이러한 경향은 표면에너지 역시 AA 함량증가에 따라 COOH 그룹에 의한 극성 강화로 표면에너지는 증가하였다. 반면, 점착력은 분자량과 반비례 관계를 보였으며 AA 함량과 경화제 함량 증가에 따라 감소하는 경향을 나타내었다.