Browsing by Author "Lee, Yu-Ching"

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Acoustic realigment of nematic liquid crystals by guided waves
(2007)
Lee, Yu-Ching
;
Shih, Wun-Bin
;
Su, Yu-Wei
;
Yin, Ching-Chung
;
機械工程學系
This paper presents an experimental evidence to correlate the acousto-optic effect of nematic liquid crystals to modal excitations of guided acoustic waves. The optic axes of liquid crystal molecules in a cell can be tilted by ultrasound at oblique incidence. The cell filled with homeotropically aligned liquid crystal material, 5CB, is fully immersed in a water tank situated between two crossed polarizers. Multi-modal guided acoustic waves have been excited in cell by changing the angle of incidence and driving frequency. The liquid crystal material sandwiched between two glass plates is regarded as a Newtonian fluid and modeled to be an isotropic hypothetical solid. The phase velocity dispersion curves and associated modal strains within the liquid crystal cell are determined numerically. Comparison between measured data and prediction reveals that guided acoustic waves have influence on the acousto-optic response of liquid crystals rather than bulk acoustic waves. Simulated results show that homeotropically and homogeneously aligned liquid crystals can be affected by symmetric and antisymmetric modes, respectively.
PSPC1-interchanged interactions with PTK6 and beta-catenin synergize oncogenic subcellular translocations and tumor progression
(2019-12-16)
Lang, Yaw-Dong
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Chen, Hsin-Yi
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Ho, Chun-Ming
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Shih, Jou-Ho
;
Hsu, En-Chi
Hepatocellular carcinoma (HCC) is one of the most lethal cancers worldwide due to metastasis. Paraspeckle component 1 (PSPC1) upregulation has been identified as an HCC pro-metastatic activator associated with poor patient prognosis, but with a lack of targeting strategy. Here, we report that PSPC1, a nuclear substrate of PTK6, sequesters PTK6 in the nucleus and loses its metastasis driving capability. Conversely, PSPC1 upregulation or PSPC1-Y523F mutation promotes epithelial-mesenchymal transition, stemness, and metastasis via cytoplasmic translocation of active PTK6 and nuclear translocation of p-catenin, which interacts with PSPC1 to augment Wnt3a autocrine signaling. The aberrant nucleocytoplasmic shuttling of active PTK6/beta-catenin is reversed by expressing the PSPC1 C-terminal interacting domain (PSPC1-CT131), thereby suppressing PSPC1/PTK6/beta-catenin-activated metastasis to prolong the survival of HCC orthotopic mice. Thus, PSPC1 is the contextual determinant of the oncogenic switch of PTK6/beta-catenin subcellular localizations, and PSPC1-CT131 functions as a dual inhibitor of PSPC1 and PTK6 with potential for improving cancer therapy.
Rationalization and Design of the Complementarity Determining Region Sequences in an Antibody-Antigen Recognition Interface
(2012-03-22)
Yu, Chung-Ming
;
Peng, Hung-Pin
;
Chen, Ing-Chien
;
Lee, Yu-Ching
;
Chen, Jun-Bo
Protein-protein interactions are critical determinants in biological systems. Engineered proteins binding to specific areas on protein surfaces could lead to therapeutics or diagnostics for treating diseases in humans. But designing epitope-specific protein-protein interactions with computational atomistic interaction free energy remains a difficult challenge. Here we show that, with the antibody-VEGF (vascular endothelial growth factor) interaction as a model system, the experimentally observed amino acid preferences in the antibody-antigen interface can be rationalized with 3-dimensional distributions of interacting atoms derived from the database of protein structures. Machine learning models established on the rationalization can be generalized to design amino acid preferences in antibody-antigen interfaces, for which the experimental validations are tractable with current high throughput synthetic antibody display technologies. Leave-one-out cross validation on the benchmark system yielded the accuracy, precision, recall (sensitivity) and specificity of the overall binary predictions to be 0.69, 0.45, 0.63, and 0.71 respectively, and the overall Matthews correlation coefficient of the 20 amino acid types in the 24 interface CDR positions was 0.312. The structure-based computational antibody design methodology was further tested with other antibodies binding to VEGF. The results indicate that the methodology could provide alternatives to the current antibody technologies based on animal immune systems in engineering therapeutic and diagnostic antibodies against predetermined antigen epitopes.
Ripple phenomenon of displays with nematic liquid crystal
(2013-04-01)
Lee, Yu-Jung
;
Liu, Tzong-Shi
;
Lee, Yu-Ching
;
機械工程學系
;
Department of Mechanical Engineering
Liquid crystal displays will show ripple if the display surface or display bracket is subjected to tactile forces. In this paper, the ripple of liquid crystal displays is investigated by dealing with elastic wave propagation in a liquid crystal layer. The model proposed for a visco-elastic medium like liquid crystals (LCs) is generalized by combining the properties of a crystalline solid and an anisotropic fluid. The governing equation is derived by using visco-elastic and wave equations. In the experiments, a linear motor is used to touch the display panel for producing ripple. Displays of three different amounts of LCs are compared. Experimental results also show that each display panel has its own wave propagation velocity that is not changed by different motor touch speeds. In addition, both theoretical analysis and experimental results depict that displays with a larger amount of LCs lead to slower ripple speed.