Browsing by Author "Chen, Chien-Yu"

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2D/3D-Display Auto-Adjustment Switch System
(2018-05-01)
Lin, Bor-Shyh
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Wu, Pei-Jung
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Chen, Chien-Yu
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影像與生醫光電研究所
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Institute of Imaging and Biomedical Photonics
Recently, 2-D/3-D switchable displays have become the mainstream in 3-D display technologies, and people can now watch 3-D movies with a naked 2-D/3-D switchable display at home. However, some studies have indicated that people might encounter visual fatigue after enjoying a 3-D film in the theater. Although 2-D/3-D switchable technologies have been widely developed, 3-D display technologies are still lacking in ergonomic and human-care factors such as reducing visual fatigue. This study proposes a novel 2-D/3-D display autoadjustment switch system to provide biofeedback functions to reduce users' visual fatigue. In addition, the relationship between the blink rate and the visual fatigue state while watching 3-D films was investigated and quantified. In this study, liquid crystal barrier technology was used to develop a 2-D/3-D switchable display, and a wearable EOG acquisition device was also designed to monitor electro-oculography signals to estimate the blink rate. Here, the 2-D/3-D display autoadjustment criterion of the proposed system was designed according to the change in the visual fatigue state as estimated from the blink rate. Finally, the experimental results show that the proposed system could effectively reduce users' visual fatigue while watching 3-D films.
An Augmented Reality Head-Up Display System with a Wide-View Eyebox
(2020-06-30)
Wu, Pei-Jung
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Chuang, Chih-Hao
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Chen, Chien-Yu
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Wu, Jeng-Han
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Lin, Bor-Shyh
This study proposes to apply the combination of two 90-degree prisms and a holographic optical element to an image-dividing element, divide an image into three through the virtual image projection system, and accurately project the images to 160 cm behind the windshield. In order to distinguish the left image, middle image, and right image at the horizontal direction, the 90-degree prism is first utilized for horizontally deflecting the light, a holographic optical element is then used for presenting the vertical deflection of the image, and finally, the images are horizontally arranged as a real image on the diffuser. An image-dividing element is eventually integrated to the virtual image projection system. Then, the divided images are made as a virtual image which is projected to 160 cm behind the windshield to combine with the street scene. The horizontal angle of view of an eyebox is increased from 2.51 degrees to 7.22 degrees, and the size of the eyebox is 31.68 cm x 12.48 cm, allowing a wide-view laser-based head-up display with the large-angle beam-splitting function being successfully designed. It would not affect the field of view on the road, and this system could reduce the space and be arranged easily in a vehicle. Therefore, this proposed system is suitable for the aftermarket.
An Energy-Recycling (ER) Technique for Reducing Power Consumption of Field Color Sequential (FCS) RGB LEDs Backlight Module
(2009)
Huang, Ming-Hsin
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Tsai, Yueh-Chang
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Wang, Shih-Wei
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Wu, Dian-Rung
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Chen, Ke-Horng
A single driving module with field color sequential (FCS) LCD technology needs to dynamically switch output voltage between 40 V for 12 series G-and B-color LEDs and 26 V for 12 series R-color LEDs at related time cluster. Thus, an energy-recycling (ER) technology is proposed to accelerate voltage settling and save compressed energy when the driving voltage is pressed from 40 V to 26 V. Only one recycling capacitor and one Schottky diode are added into the power structure of synchronous boost converter for composing the proposed ER technology. A proposed energy-recycling mode (ERM) controller is plugged into a boundary current mode (BCM) controller to control energy delivering and recycling. The proposed ER technology was fabricated by TSMC 0.25 mu m 2.5/5 V BCD process. Experimental results demonstrate fast and efficient tracking performance of driving voltage is achieved.
Inhibition of p38 MAPK-dependent MutS homologue-2 (MSH2) expression by metformin enhances gefitinib-induced cytotoxicity in human squamous lung cancer cells
(2013-12-01)
Ko, Jen-Chung
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Chiu, Hsien-Chun
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Wo, Ting-Yu
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Huang, Yi-Jhen
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Tseng, Sheng-Chieh
Objectives: Gefitinib, a quinazoline-derived tyrosine kinase inhibitor, has anti-tumor activity in vivo and in vitro. Human MutS homologue-2 (MSH2) plays a central role in promoting genetic stability by correcting DNA replication errors. The present study investigated the effects of p38 mitogen-activated protein kinase (MAPK) signal on gefitinib-induced MSH2 expression in two human non-small cell lung squamous cancer cell lines. Materials and methods: After the gefitinib treatment, the expressions of MSH2 mRNA were determined by real-time PCR and RT-PCR analysis. Protein levels of MSH2, phospho-MKK3/6, phospho-p38 MAPK were determined by Western blot analysis. We used specific MSH2, and p38 MAPK small interfering RNA to examine the role of p38 MAPK-MSH2 signal in regulating the chemosensitivity of gefitinib. Cell viability was assessed by MTS assay, trypan blue exclusion, and colony-forming ability assay. Results: Exposure of gefitinib increased MSH2 protein and mRNA levels, which was accompanied by MKK3/6-p38 MAPK activation in H520 and H1703 cells. Moreover, blocking p38 MAPK activation by SB202190 significantly decreased gefitinib-induced MSH2 expression by increasing mRNA and protein instability. In contrast, enhancing p38 activation using constitutively active MKK6 (MKK6E) increased MSH2 protein and mRNA levels. Specific inhibition of MSH2 expression by siRNA enhanced gefitinib-induced cytotoxicity. Metformin, an anti-diabetic drug, might reduce cancer risk. In human lung squamous cancer cells, metformin decreased gefitinib-induced MSH2 expression and augmented the cytotoxic effect and growth inhibition by gefitinib. Transient expression of MKK6E or HA-p38 MAPK vector could abrogate metformin and gefitinib-induced synergistic cytotoxic effect in H520 and H1703 cells. Conclusion: Together, down-regulation of MSH2 expression can be a possible strategy to enhance the sensitivity of gefitinib to human lung squamous cancer cells. (C) 2013 Elsevier Ireland Ltd. All rights reserved.
Molecular cloning, sequence analysis and functional characterization of the gene cluster for biosynthesis of K-252a and its analogs
(2009)
Chiu, Hsien-Tai
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Chen, Yi-Lin
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Chen, Chien-Yu
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Jin, Chyn
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Lee, Meng-Na
Among the indolocarbazole alkaloids of antitumor antibiotics, K-252a represents a structurally unique indolocarbazole glycoside and exhibits potent neuroprotective and broad anticancer activities. K-252a consists of K-252c and the unusual dihydrostreptose moiety, linked together with oxidative and glycosidic C-N bonds. Herein, we reported a complete sequence of an approximately 45 kb genomic fragment harboring the gene cluster for the biosynthesis of indolocarbazole alkaloids in Nocardiopsis sp. K-252 (NRRL15532). The sequence of 35 open reading frames discovered several new, critical genes, hence shedding new light on biosynthesis, resistance and regulation of K-252a and its analogs. To functionally characterize the gene cluster in vitro and in enzyme level, a multigene expression cassette containing the K-252c biosynthetic genes was constructed and successfully overexpressed in Escherichia coli to yield soluble proteins for cell-free tandem enzymatic assays. Consequently, the heterologous expression with soluble NokA and NokB led to in vitro production of chromopyrrolic acid (CPA), thereby providing functional evidence for K-252c biosynthesis. Moreover, a facile production of CPA in culture broth was successfully accomplished by using an in vivo biotransformation of L-tryptophan with E. coli harboring the gene cassette. Importantly, by sequence analysis and the functional characterization here and in the companion paper, biosynthetic pathways leading to formation of K-252a and its analogs were hence proposed. Together, the results provide critical information and materials useful for combinatorial biosynthesis of K-252a and its analogs for therapeutic applications.
Performance Characterization of Dye-Sensitized Photovoltaics under Indoor Lighting
(2017-04-20)
Chen, Chia-Yuan
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Jian, Zih-Hong
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Huang, Shih-Han
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Lee, Kun-Mu
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Kao, Ming-Hsuan
Indoor utilization of emerging photovoltaics is promising; however, efficiency characterization under room lighting is challenging. We report the first round-robin interlaboratory study of performance measurement for dye-sensitized photovoltaics (cells and mini-modules) and one silicon solar cell under a fluorescent dim light. Among 15 research groups, the relative deviation in power conversion efficiency (PCE) of the samples reaches an unprecedented 152%. On the basis of the comprehensive results, the gap between photometry and radiometry measurements and the response of devices to the dim illumination are identified as critical obstacles to the correct PCE. Therefore, we use an illuminometer as a prime standard with a spectroradiometer to quantify the intensity of indoor lighting and adopt the reverse-biased current voltage (I-V) characteristics as an indicator to qualify the I-V sampling time for dye-sensitized photovoltaics. The recommendations can brighten the prospects of emerging photovoltaics for indoor applications.
Sapphire surface patterning using femtosecond laser micromachining
(2012-11-01)
Chang, Cho-Wei
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Chen, Chien-Yu
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Chang, Tien-Li
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Ting, Chia-Jen
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Wang, Chien-Ping
This study presents an alternative method for micron-resolution patterning of a sapphire surface utilizing the characteristic of an ultra-short pulse (10(-15) s) from ytterbium (Yb) femtosecond laser (FS-laser) irradiation. Conventional processes often involve several steps, such as wet chemical or dry etching, for surface structuring of sapphire. In this study, two-dimensional array patterns on the sapphire surface with an area of 5x5 mm(2) and a depth of 1.2 +/- 0.1 mu m can be directly and easily fabricated by a single step of the FS-laser process, which involves 350-fs laser pulses with a wavelength of 517 nm at a repetition rate of 100 kHz. The measured ablation depths on the sapphire surface display that the proposed process can be under well-controlled conditions. Based on the design changes for being quickly implemented in the micromachining process, a FS laser can be a promising and competitive tool for patterning sapphire with an acceptable quality for industrial usage.
Tamoxifen enhances erlotinib-induced cytotoxicity through down-regulating AKT-mediated thymidine phosphorylase expression in human non-small-cell lung cancer cells
(2014-03-01)
Ko, Jen-Chung
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Chiu, Hsien-Chun
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Syu, Jhan-Jhang
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Jian, Yi-Jun
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Chen, Chien-Yu
Tamoxifen is a triphenylethylene nonsteroidal estrogen receptor (ER) antagonist used worldwide as an adjuvant hormone therapeutic agent in the treatment of breast cancer. However, the molecular mechanism of tamoxifen-induced cytotoxicity in non-small cell lung cancer (NSCLC) cells has not been identified. Thymidine phosphorylase (TP) is an enzyme of the pyrimidine salvage pathway which is upregulated in cancers. In this study, tamoxifen treatment inhibited cell survival in two NSCLC cells, H520 and H1975. Treatment with tamoxifen decreased TP mRNA and protein levels through AKT inactivation. Furthermore, expression of constitutively active AKT (AKT-CA) vectors significantly rescued the decreased TP protein and mRNA levels in tamoxifen-treated NSCLC cells. In contrast, combination treatment with PI3K inhibitors (LY294002 or wortmannin) and tamoxifen further decreased the TP expression and cell viability of NSCLC cells. Knocking down TP expression by transfection with small interfering RNA of TP enhanced the cytotoxicity and cell growth inhibition of tamoxifen. Erlotinib (Tarceva, OSI-774), an orally available small molecular inhibitor of epidermal growth factor receptor (EGFR) tyrosine kinase, is approved for clinical treatment of NSCLC. Compared to a single agent alone, tamoxifen combined with erlotinib resulted in cytotoxicity and cell growth inhibition synergistically in NSCLC cells, accompanied with reduced activation of phospho-AKT and phospho-ERK1/2, and reduced TP protein levels. These findings may have implications for the rational design of future drug regimens incorporating tamoxifen and erlotinib for the treatment of NSCLC. (C) 2014 Elsevier Inc. All rights reserved.
The comparison of accommodative response and ocular movements in viewing 3D and 2D displays
(2017-09-01)
Cho, Ta-Hsiung
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Chen, Chien-Yu
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Wu, Pei-Jung
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Chen, Kun-Shiang
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Yin, Li-Te
Some people often appear asthenopia symptoms of eye fatigue, double vision, nausea, and dizziness while viewing 3D movies. By testing the changes of accommodation function and ocular movements during watching 3D and 2D movies, the factors in visual discomfort are confirmed in this study. 20 subjects with normal visual acuity and binocular vision function view 3D and 2D movies with the same content for 30 min, and the amplitude of accommodation, binocular vergence ability, stereo-acuity, and tear break-up time of the subjects before and after viewing the films are measured. Furthermore, an open-field auto-refractor is utilized for synchronously testing the change of accommodative response while viewing 3D and 2D films, and Skalar IRIS tracking system is applied to record ocular movements through infrared positioning. In comparison with viewing 2D movies, the accommodative response and ocular movements reveal obvious changes while viewing 3D movies. The accommodation ability and binocular vergence ability obviously drop after viewing 3D movies; moreover, the stability of stereo-acuity and tear film also gets worse. The changes of such physiological factors might be the major cause of asthenopia. (C) 2017 Elsevier B.V. All rights reserved.
Thermal and angular dependence of next-generation photovoltaics under indoor lighting
(1970-01-01)
Chen, Chia-Yuan
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Kuo, Ting-Yang
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Huang, Chien-Wu
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Jian, Zih-Hong
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Hsiao, Po-Tsung
Next-generation photovoltaic technologies such as dye-sensitized solar cells, organic thin-film photovoltaics and perovskite solar cells are promising to efficiently harvest ambient light energy. However, more and deeper understanding of their photovoltaic characteristics is essential to create new applications under room light illumination. In this study, for the first time, the difference in temperature coefficients and angular dependence of photovoltaic parameters for the large-area devices are investigated systematically under the compact fluorescent lamp and light-emitting diode light. These emerging photovoltaic devices, compared with the single crystalline silicon solar cells, not only have higher open-circuit voltage (up to approximate 1 V) and better power conversion efficiency (in the range of 9.2% similar to 22.6%) but also exhibit less temperature dependent voltage and output power (< -0.6% degrees C-1), as well as broader angular response (over 75 degrees). The state-of-the-art dye-sensitized and organic thin-film devices also show advantageously positive temperature coefficients of current, and the latter even has positive thermal dependence of fill factor. These features suggest the next-generation photovoltaic devices are more favorable than the conventional crystalline silicon solar cells for real-life indoor applications.