Browsing by Author "Chen, Yu-Cheng"

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A fusion protein composed of receptor binding domain of vascular endothelial growth factor-A and constant region fragment of antibody: angiogenesis antagonistic activity
(2011-05-01)
Tseng, Feng-Jen
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Liu, Yen-Ku
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Chung, Yo-Shong
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Lin, Yu-Ling
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Chen, Chia-Hung
Vascular endothelial growth factor (VEGF) promotes the growth of solid tumor mainly via VEGF receptor-1 and receptor-2, which are expressed preferentially in proliferating endothelial cells. Therefore, a strategy for simultaneous blockage of both VEGF receptors may have a useful therapeutic effect in tumor growth. In this study, we utilized a fusion protein which is composed of receptor binding domain of VEGF-A (RBDV) and the constant region fragment (Fc) of a human immunoglobulin G1 (IgG1), to interfere with the growth of human umbilical vein endothelial cells (HUVECs) via VEGF receptors. The results showed that RBDV-IgG1 Fc was able to bind with both VEGF receptor-1 and receptor-2. In addition, RBDV-IgG1 Fc could decrease VEGF-induced proliferation and tube formation among HUVECs. Moreover, the cytotoxic test showed RBDV-IgG1 Fc could also enhance the cytotoxic activity of human natural killing cells. The data are suggesting that the fusion protein, RBDV-IgG1 Fc, may have potential as an angiogenesis antagonist for future tumor therapy.
A fusion protein with the receptor binding domain of vascular endothelial growth factor-A (VEGF-A) is an antagonist of angiogenesis in cancer treatment
(2010-11-01)
Tseng, Feng-Jen
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Chen, Yu-Cheng
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Lin, Yu-Ling
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Tsai, Nu-Man
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Lee, Ru-Ping
Vascular endothelial growth factor (VEGF) is an angiogenic factor that signals through VEGFR-1 and VEGFR-2, which are expressed preferentially in proliferating endothelial cells. Thus, simultaneous blockage of both VEGF receptors may provide a more efficient therapeutic response in cancer treatment. We created a recombinant fusion protein (RBDV-IgG1 Fc), which is composed of the receptor binding domain of human VEGF-A (residues 8-109) and the Fc region of human IgG1 immunoglobulin. The recombinant protein can bind to both mouse VEGFR-1 and VEGFR-2 to decrease VEGF-induced proliferation and tube formation of endothelial cells in vitro. In this study, the RBDV-IgG1 Fc fusion protein reduced the effects of proliferation, migration and tube formation induced by VEGF in murine endothelial cells in vitro. In vivo tumor therapy with RBDV-IgG1 Fc resulted in tumor inhibition by reducing angiogenesis. Pathological evidence also shows that RBDV-IgG1 Fc can seriously damage vessels, causing the death of tumor cells. These findings suggest that this chimeric protein has potential as an angiogenesis antagonist in tumor therapy.
CHIMNEY-ENHANCED DESIGN APPLIED ON THE THERMAL MANAGEMENT OF LED VEHICLE HEADLAMP
(2016)
Lin, Sheam-Chyun
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Chen, Yu-Cheng
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Wu, Yu-Chun
;
Yen, Hung-Cheng
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機械工程學系
LED vehicle headlamp consists of several high-power LEDs and thermal module inside an enclosed space, and locates near the high-temperature engine compartment. Certainly, these factors results in a challenging task on the thermal management of headlamp. Obviously, the temperature stratification inside this bounded region is an unfavorable phenomenon for the natural-convection thermal module. This study utilizes the chimney effect to achieve a more uniform temperature distribution and thus enhance the heat-dissipation ability. Firstly, an enclosed space is selected for executing the parametric study on the chimney geometry. Several effective alternatives are obtained and verified via both numerical and experimental means on the chimney design. Also, a significant 4.6 degrees C reduction on LED junction temperature is attained on the best chimney-enhanced module. Then, these guidelines are applied to a commercial LED headlamp. Consequently, a range of 3.8 similar to 4.6 degrees C decrease on LEDs is found for this innovative chimney thermal module.
Enhancement of anti-murine colon cancer immunity by fusion of a SARS fragment to a low-immunogenic carcinoembryonic antigen
(1970-01-01)
Lin, Chen-Si
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Kao, Shih-Han
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Chen, Yu-Cheng
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Li, Chi-Han
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Hsieh, Yuan-Ting
"Background: It is widely understood that tumor cells express tumor-associated antigens (TAAs), of which many are usually in low immunogenicity; for example, carcinoembryonic antigen (CEA) is specifically expressed on human colon cancer cells and is viewed as a low-immunogenic TAA. How to activate host immunity against specific TAAs and to suppress tumor growth therefore becomes important in cancer therapy development. Results: To enhance the immune efficiency of CEA in mice that received, we fused a partial CEA gene with exogenous SARS-CoV fragments. Oral vaccination of an attenuated Salmonella typhimurium strain transformed with plasmids encoding CEA-SARS-CoV fusion gene into BALB/c mice elicited significant increases in TNF-alpha and IL-10 in the serum. In addition, a smaller tumor volume was observed in CT26/CEA-bearing mice who received CEA-SARS-CoV gene therapy in comparison with those administered CEA alone. Conclusion: The administration of fusing CEA-SARS-CoV fragments may provide a promising strategy for strengthening the anti-tumor efficacy against low-immunogenic endogenous tumor antigens."
Graphene Oxide Based Nanocarrier Combined with a pH-Sensitive Tracer: A Vehicle for Concurrent pH Sensing and pH-Responsive Oligonucleotide Delivery
(2015-06-03)
Hsieh, Chia-Jung
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Chen, Yu-Cheng
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Hsieh, Pei-Ying
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Liu, Shi-Rong
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Wu, Shu-Pao
We chemically tuned the oxidation status of graphene oxide (GO) and constructed a GO-based nanoplatform combined with a pH-sensitive fluorescence tracer that is designed for both pH sensing and pH-responsive drug delivery. A series of GOs oxidized to distinct degrees were examined to optimize the adsorption of the model drug, poly dT(30). We determined that highly oxidized GO was a superior drug-carrier candidate in vitro when compared to GOs oxidized to lesser degrees. In the cell experiment, the synthesized pH-sensitive rhodamine dye was first applied to monitor cellular pH; under acidic conditions, protonated rhodamine fluoresces at 588 mm (lambda(ex) = 561 nm). When the nanocarrier was introduced into cells, a rhodamine-triggered competition reaction occurred, and this led to the release of the oligonucleotides and the quenching of rhodamine fluorescence by GO. Our results indicate high drug loading (FAM-dT(30)/GO = 25/50 mu g/mL) and rapid cellular uptake (<0.5 h) of the nanocarrier which can potentially be used for targeted RNAi delivery to the acidic milieu of tumors.
Non-metallic nanomaterials in cancer theranostics: a review of silica- and carbon-based drug delivery systems
(2013-08-01)
Chen, Yu-Cheng
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Huang, Xin-Chun
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Luo, Yun-Ling
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Chang, Yung-Chen
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Hsieh, You-Zung
The rapid development in nanomaterials has brought great opportunities to cancer theranostics, which aims to combine diagnostics and therapy for cancer treatment and thereby improve the healthcare of patients. In this review we focus on the recent progress of several cancer theranostic strategies using mesoporous silica nanoparticles and carbon-based nanomaterials. Silicon and carbon are both group IV elements; they have been the most abundant and significant non-metallic substances in human life. Their intrinsic physical/chemical properties are of critical importance in the fabrication of multifunctional drug delivery systems. Responsive nanocarriers constructed using these nanomaterials have been promising in cancer-specific theranostics during the past decade. In all cases, either a controlled texture or the chemical functionalization is coupled with adaptive properties, such as pH-, light-, redox- and magnetic field-triggered responses. Several studies in cells and mice models have implied their underlying therapeutic efficacy; however, detailed and long-term in vivo clinical evaluations are certainly required to make these bench-made materials compatible in real bedside circumstances.
Numerical investigation on noise reduction for an in-line fan equipped with Helmholtz resonator
(2016-11)
Lin, Sheam-Chyun
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Chen, Yu-Cheng
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Chen, Yen-Jiang
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Yen, Hung-Cheng
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機械工程學系
This research intends to analyze and improve the flow-induced noise of an in-line fan with Helmholtz resonator by the numerical simulation. At first, the flow and acoustic fields associated with the fan are simulated and analyzed via the CFD simulation. Subsequently, a thorough understanding on the aerodynamic and acoustic features of this mixed-flow fan is achieved. Later, to reduce the fan noise, a set of Helmholtz resonators for this inline-fan is designed and installed onto the critical regions inside the fan. Also, the flow-induced-noise reduction due to the resonator is examined and discussed in details. As a result, the maximum noise reductions on the 1st and the 2nd characteristic frequencies are obtained at 6.9 dBA and 9.8 dBA, respectively. Moreover, there is a minor noise-elimination effect found on the other harmonic frequency while the significant result appears on the designed characteristic frequency. However, all resonators used yield a significant noise reduction at the second BFF. In conclusions, a comprehensive parametric study on Helmholtz resonator is carried out and summarized for attaining a design guideline for its application on the in-line fan. The accomplishment of this study provides a systematic scheme of noise reduction for an inline-fan with the addition of Helmholtz resonator design.
Oligonucleotides as 'bio-solvent' for in situ extraction and functionalisation of carbon nanoparticles
(2014-01-01)
Chen, Yu-Cheng
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Wen, Cheng-Che
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Liau, Ian
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Hsieh, You-Zung
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Hsu, Hsin-Yun
A simple yet novel one-pot approach is developed to prepare carbon nanoparticles with diameters of similar to 2 nm and modified by oligonucleotides. We use single-stranded deoxyribonucleic acid (ssDNA), which serves as a unique 'bio-solvent' for carbon nanoparticle (CNP) preparation and as a target molecule for functionalisation. Proposed interactions relevant to the stabilisation of the final oligonucleotide-CNP complex include pi-pi stacking and pi-HN bonding with sp(2) carbon atoms on the CNP surface. Furthermore, oligonucleotide-enriched CNPs can be readily extracted within seconds from a crude mixture of single-walled carbon nanotubes (SWCNTs) without any need for post-synthesis chemical modification. The established CNPs are biocompatible, possess intrinsic fluorescence, and do not result in the undesirable photobleaching effect, rendering them potential candidates for in vivo biological applications.
Oligonucleotides as \'bio-solvent\' for in situ extraction and functionalisation of carbon nanoparticles
(2014-01-01)
Chen, Yu-Cheng
;
Wen, Cheng-Che
;
Liau, Ian
;
Hsieh, You-Zung
;
Hsu, Hsin-Yun
A simple yet novel one-pot approach is developed to prepare carbon nanoparticles with diameters of similar to 2 nm and modified by oligonucleotides. We use single-stranded deoxyribonucleic acid (ssDNA), which serves as a unique \'bio-solvent\' for carbon nanoparticle (CNP) preparation and as a target molecule for functionalisation. Proposed interactions relevant to the stabilisation of the final oligonucleotide-CNP complex include pi-pi stacking and pi-HN bonding with sp(2) carbon atoms on the CNP surface. Furthermore, oligonucleotide-enriched CNPs can be readily extracted within seconds from a crude mixture of single-walled carbon nanotubes (SWCNTs) without any need for post-synthesis chemical modification. The established CNPs are biocompatible, possess intrinsic fluorescence, and do not result in the undesirable photobleaching effect, rendering them potential candidates for in vivo biological applications.
Profile and interface control of hybrid organic-silicon nanorod solar cells
(2015)
Chen, Yu-Cheng
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Lin, Yi-Cheng
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Yu, Liang-Chian
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Yu, Peichen
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光電工程學系
Hybrid organic-silicon solar cells are promising candidates for next-generation photovoltaics due to their low fabrication cost and scalable roll-to-roll processes. However, the power conversion efficiency (PCE) cannot compete with those of traditional silicon solar cells yet mostly due to surface reflection and interface recombination losses. In this work, we investigate the sidewall profile and interface defects of silicon nanorod templates, fabricated by means of polystyrene lithography, followed by metal-assisted chemical etch (MACE), for hybrid photovoltaics. The control of nanorod sidewall profile is important to organic surface coverage, as well as optical absorption for thin-silicon substrates, whereas the control of interface defects is important to boost the open-circuit voltage of hybrid devices. We systematically compared the optical and electrical characteristics of hybrid organic-silicon nanorod (Si NR) devices made with different noble metal etching catalysts: gold (Au) and silver (Ag), which result in different surface morphologies. The preliminary results show that Si NRs made of Ag catalysts have lower interface defects than those of Au catalysts. After passivated by 10nm-Al2O3, the minority carrier lifetime is 157 mu sec (A g) versus 29 mu sec (Au). Moreover, a PCE of 11.9% is achieved with the hybrid solar cells using Ag catalysts without any post-etching surface treatment, where the short-circuit current is as high as >34 mA/cm(2) enhanced by the nearly periodical pillar arrangement. The Si NR template made with Au catalysts requires further damage removal etch (DRE), which also lead to a high PCE of 11.37% and Jsc of similar to 34 mA/cm(2) . Currently optimization of device structure and fabrication technique is still in process and more experimental and simulation data will be presented.
Pseudo-multicolor carbon dots emission and the dilution-induced reversible fluorescence shift
(2016-01-01)
Chen, Yu-Cheng
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Nien, Cheng-Yung
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Albert, Karunya
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Wen, Cheng-Che
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Hsieh, You-Zung
Size- and color-tunable carbon dots (CDs) that emit blue to red using a single precursor in pure water were achieved by simple concentration and reaction time control. Distinct from conventional fluorophores, a reversible spectra shift of CD was observed upon dilution which could be a result of altered CD-CD inter-particle interaction, leading to minimized self- absorption.
Realizing the Real-time Gaze Redirection System with Convolutional Neural Network
(2018-01-01)
Hsu, Chih-Fan
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Chen, Yu-Cheng
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Wang, Yu-Shuen
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Lei, Chin-Laung
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Chen, Kuan-Ta
Retaining eye contact of remote users is a critical issue in video conferencing systems because of parallax caused by the physical distance between a screen and a camera. To achieve this objective, we present a real-time gaze redirection system called Flx-gaze to post-process each video frame before sending it to the remote end. Specifically, we relocate and relight the pixels representing eyes by using a convolutional neural network (CNN). To prevent visual artifacts during manipulation, we minimize not only the L2 loss function but also four novel loss functions when training the network. Two of them retain the rigidity of eyeballs and eyelids; and the other two prevent color discontinuity on the eye peripheries. By leveraging the CPU and the GPU resources, our implementation achieves real-time performance (i.e., 31 frames per second). Experimental results show that the gazes redirected by our system are of high quality under this restrict time constraint. We also conducted an objective evaluation of our system by measuring the peak signal-to-noise ratio (PSNR) between the real and the synthesized images.
Solution p-doped fluorescent polymers for enhanced charge transport of hybrid organic-silicon nanowire photovoltaics
(2016-07)
Tsai, Pei-Ting
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Li, Ming-Chin
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Lai, Yi-Chun
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Tseng, Wei-Hsuan
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Wu, Chih-I
The solution p-type doping of various conjugated polymers and small molecules via blending with tetrafluorotetracyano-quinodimethane (F4-TCNQ) is investigated to facilitate hole transport for hybrid organic-silicon-nanowire solar cells. Among all, the highly-fluorescent conjugated polymers such as poly(9,9-dioctylfluorenyl-2,7-diyl) (PFO) demonstrate superior transport characteristics, where both the device fill-factor and power conversion efficiency (PCE) are positively correlated with the doping concentration. The best PCE achieves 13.66% from the device with 30% p-doped PFO, compared to the reference at 12.50%. The enhancement is ascribed to the efficient interfacial charge-carrier recombination with minimal energy losses. A vertically graded doping profile is further revealed with F4-TCNQ molecules preferentially accumulated near the silicon surface. (C) 2016 Elsevier B.V. All rights reserved.
Study on degradation of crystallized laterally grown poly-Si TFT under Dynamic Stress
(2007)
Lu, Hau-Yan
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Chung, Wan-Fang
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Tseng, Tzu-Yi
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Chen, Yu-Cheng
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Liu, Po-Tsun
The influence of protrusion grain boundary on the degradation of crystallized laterally grown poly-Si TFT under Dynamic Stress is investigated. The degradation of TFT with protrusion grain boundary is more severe and the different damage of the source/drain junction in the TFT with grain boundary closed to source side.
System gains configuration and coordination of redundant degrees of freedom by genetic algorithms for multi-axis machine system in manufacturing
(2007-05-01)
Chin, Jih-Hua
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Chen, Yu-Cheng
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機械工程學系
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Department of Mechanical Engineering
In multi-axis machine tool systems, the configuration of system gains and the coordination of redundant degrees of freedom are often a problem of insurmountable difficulty. This study explores the use of a nontraditional scheme, the genetic algorithm, in the configuration of system gains and exploitation of redundant degrees of freedom. The off-line gains configuration functioned as a kind of system design which may serve as a starting point for on-line adaptation. The allocation of redundant DOF was done on-line. The success in this work inspired the idea of future on-line GA application and the possibility of integration of GA with other non-traditional algorithms for manufacturing. (c) 2007 Elsevier Ltd. All rights reserved.
The treatment of propofol induced the TGF-beta 1 expression in human endothelial cells to suppress endocytosis activities of monocytes
(2010-12-01)
Li, Chi-Han
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Lee, Ru-Ping
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Lin, Yu-Ling
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Lin, Chen-Si
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Hsu, Bang-Gee
Propofol anesthesia and sedation are known to downregulate the functions of many hematopoietic cells, such as macrophages and neutrophils, in vivo. However, the effects of propofol on secretion of the regulatory cytokine transforming growth factor beta 1 (TGF-beta 1) in vivo are unknown. In this study, the effects of propofol on TGF-beta 1 expression in human peripheral blood mononuclear cells, umbilical vein endothelial cells (HUVECs), lymphocytes (Jurkat) and monocytes (THP-1) were tested. Moreover, these sera were also tested for regulatory activity on monocyte endocytosis with or without treatment with the TGF-beta 1 pathway inhibitor SB431542. Propofol raised levels of both total and activated TGF-beta 1 in propofol-treated patient sera after surgical operations. Furthermore, propofol induced secretion of latent TGF-beta 1 in HUVEC cells and enhanced TGF-beta 1 activation in THP-1 and Jurkat cells in vitro. Additionally, sera from propofol-treated patients suppressed monocyte endocytosis ex vivo, an effect that was abrogated by the TGF-beta 1 pathway inhibitor SB431542. (C) 2010 Elsevier Ltd. All rights reserved.