Browsing by Author "Lai, Yu-Cheng"

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Characterization of the Mechanodynamic Response of Cardiomyocytes with Atomic Force Microscopy
(2013-02-05)
Chang, Wei-Tien
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Yu, David
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Lai, Yu-Cheng
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Lin, Kuen-You
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Liau, Ian
Characterization of the Mechanodynamic Response of Cardiomyocytes with Atomic Force Microscopy
Direct View and Projection Switchable Mobile Display
(2009-01-01)
Huang, Hsin-Hsuan
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Chen, Cheng-Huan
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Lai, Yu-Cheng
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Chang, Yu-Cheng
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Huang, Yi-Pai
The function of mobile phone becomes more versatile as a personal assistant. In order to make display device optimized for different function of the mobile phone, this paper proposes a display device which can be switched among 2D direct view, 3D direct view and projection modes while using single liquid crystal(LC) panel as image source. The device features a highly collimated backlight unit and polymer dispersed liquid crystal(PDLC) diffuser at the back of the LC panel, and a switchable lenticular array as well as a stretchable projection lens in front. The ray tracing simulation has shown well controlled light path of the backlight module and sufficient image quality of the projection lens while maintaining the compactness of the device for mobile application.
Optical assessment of the cardiac rhythm of contracting cardiomyocytes in vitro and a pulsating heart in vivo for pharmacological screening
(2014-05-01)
Lai, Yu-Cheng
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Chang, Wei-Tien
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Lin, Kuen-You
;
Liau, Ian
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應用化學系
Our quest in the pathogenesis and therapies targeting human heart diseases requires assessment of the contractile dynamics of cardiac models of varied complexity, such as isolated cardiomyocytes and the heart of a model animal. It is hence beneficial to have an integral means that can interrogate both cardiomyocytes in vitro and a heart in vivo. Herein we report an application of dual-beam optical reflectometry to determine noninvasively the rhythm of two representative cardiac models-chick embryonic cardiomyocytes and the heart of zebrafish. We probed self-beating cardiomyocytes and revealed the temporally varying contractile frequency with a short-time Fourier transform. Our unique dual-beam setup uniquely records the atrial and ventricular pulsations of zebrafish simultaneously. To minimize the cross talk between signals associated with atrial and ventricular chambers, we particularly modulated the two probe beams at distinct frequencies and extracted the signals specific to individual cardiac chambers with phase-sensitive detection. With this setup, we determined the atrio-ventricular interval, a parameter that is manifested by the electrical conduction from the atrium to the ventricle. To demonstrate pharmacological applications, we characterized zebrafish treated with various cardioactive and cardiotoxic drugs, and identified abnormal cardiac rhythms and atrioventricular (AV) blocks of varied degree. In light of its potential capability to assess cardiac models both in vitro and in vivo and to screen drugs with cardioactivity or toxicity, we expect this approach to have broad applications ranging from cardiopharmacology to developmental biology. (C) 2014 Optical Society of America
Rayleigh-instability-driven morphology transformation of electrospun polymer fibers imaged by in situ optical microscopy and stimulated Raman scattering microscopy
(2014-01-01)
Lee, Ting-Hsien
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Chiu, Yu-Jing
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Lai, Yu-Cheng
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Fan, Ping-Wen
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Kuo, Tyng-Yow
Electrospinning is one of the most common methods to prepare polymer fibers with sizes ranging from several nanometers to hundreds of micrometers. In most studies of electrospun polymer fibers, the properties and morphologies of polymer fibers are controlled by changing the electrospinning conditions. Few studies focus on the post-treatments of polymer fibers, which are critical for many fiber-based applications. In this work, we investigate the morphology transformation of electrospun polystyrene (PS) fibers annealed on top of poly(methyl methacrylate) (PMMA) film-coated glass substrates. In situ optical microscopy and stimulated Raman scattering (SRS) microscopy are used to observe the transformation process, which is driven by the Rayleigh instability, the surface tensions, and the interfacial tensions of polymers. Depending on the thickness of the underlying PMMA films, the electrospun PS fibers may transform into hemispheres or disks. The growth rates of the undulating amplitude are also affected by the film thickness.
Toward Functional Screening of Cardioactive and Cardiotoxic Drugs with Zebrafish in Vivo Using Pseudodynamic Three-Dimensional Imaging
(2014-02-18)
Lin, Kuen-You
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Chang, Wei-Tien
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Lai, Yu-Cheng
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Liau, Ian
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應用化學系
Given the high mortality in patients with cardiovascular diseases and the life-threatening consequences of drugs with unforeseen adverse effects on hearts, a critical evaluation of the pharmacological response of cardiovascular function on model animals is important especially in the early stages of drug development. We report a proof-of-principle study to demonstrate the utility of zebrafish as an analytical platform to predict the cardiac response of new drugs or chemicals on human beings. With pseudodynamic 3D imaging, we derive individual parameters that are central to the cardiac function of zebrafish, including the ventricular stroke volume, ejection fraction, cardiac output, heart rate, diastolic filling function, and ventricular mass. We evaluate both inotropic and chronotropic responses of the heart of zebrafish treated with drugs that are commonly prescribed and possess varied known cardiac activities. We reveal deranged cardiac function of a zebrafish model of cardiomyopathy induced with a cardiotoxic drug. The cardiac function of zebrafish exhibits a pharmacological response similar to that of human beings. We compare also cardiac parameters obtained in this work with those derived with conventional 2D approximation and show that the latter tends to overestimate the cardiac parameters and produces results of greater variation. In view of the growing interest of using zebrafish in both fundamental and translational biomedical research, we envisage that our approach should benefit not only contemporary pharmaceutical development but also exploratory research such as gene, stem cell, or regenerative therapies targeting congenital or acquired heart diseases.