Browsing by Author "Chang, Chia-Chen"

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Cholesteryl alpha-D-glucoside 6-acyltransferase enhances the adhesion of Helicobacter pylori to gastric epithelium
(2020-03-13)
Jan, Hau-Ming
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Chen, Yi-Chi
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Yang, Tsai-Chen
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Ong, Lih-Lih
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Chang, Chia-Chen
Helicobacter pylori, the most common etiologic agent of gastric diseases including gastric cancer, is auxotrophic for cholesterol and has to hijack it from gastric epithelia. Upon uptake, the bacteria convert cholesterol to cholesteryl 6 '-O-acyl-alpha-D-glucopyranoside (CAG) to promote lipid raft clustering in the host cell membranes. However, how CAG appears in the host to exert the pathogenesis still remains ambiguous. Herein we identified hp0499 to be the gene of cholesteryl alpha-D-glucopyranoside acyltransferase (CGAT). Together with cholesteryl glucosyltransferase (catalyzing the prior step), CGAT is secreted via outer membrane vesicles to the host cells for direct synthesis of CAG. This significantly enhances lipid rafts clustering, gathers adhesion molecules (including Lewis antigens and integrins alpha 5, beta 1), and promotes more bacterial adhesion. Furthermore, the clinically used drug amiodarone was shown as a potent inhibitor of CGAT to effectively reduce the bacterial adhesion, indicating that CGAT is a potential target of therapeutic intervention. Jan et al. identify cholesteryl alpha-D- glucopyranoside acyltransferase as a key enzyme in Helicobacter pylori's synthesis of cholesteryl 6'-O-acyl-alpha-D-glucopyranoside, which promotes bacterial adhesion. This study provides insights into the H. pylori-induced pathogenesis and therapeutic strategies against it.
Cooperative Traffic Control With Green Wave Coordination for Multiple Intersections Based on the Internet of Vehicles
(2017-07-01)
Chen, Lien-Wu
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Chang, Chia-Chen
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資訊工程學系
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Department of Computer Science
Traffic congestion is a critical concern in most cities. Inefficient traffic control wastes time and fuel, and causes harmful carbon emissions, road accidents, and many economic problems. This paper proposes a cooperative traffic control framework for optimizing the global throughput and travel time for multiple intersections. Adjacent intersections are considered in analyzing their joint passing rates and attempting to maximize the number of vehicles traveling through a road network. The proposed framework provides fairness for each road segment and realizes the green wave concept for arterial roads. This paper extends previous studies by considering the passing rates of continuous road segments and coordinating traffic signals of multiple intersections. The simulation results show that the approach outperforms existing schemes in that it achieves a high global throughput, reduces the average waiting time, lowers the total travel time, and decreases average CO2 emissions. To verify the feasibility of the proposed framework, a wireless access in vehicular environments/dedicated short-range communications-based prototype for lane-level dynamic traffic control is designed and implemented.
Demo Abstract: A Video-Based Metropolitan Positioning System with Centimeter-Grade Localization for VANETs
(2015)
Chen, Lien-Wu
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Ho, Yu-Fan
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Chang, Chia-Chen
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Tseng, Yu-Chee
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資訊工程學系
In this paper, we propose a video-based metropolitan positioning system (V-MPS) for providing centimeter-grade localization in vehicular networks. The V-MPS system integrates vehicular networks with installed roadside/intersection cameras to provide positioning information to vehicles on the road. V MPS can estimate the precise position of a vehicle and detect the located lane for each vehicle. To the best of our knowledge, V MPS is the first positioning system which provides the following features: 1) it achieves the centimeter-grade positioning accuracy for vehicular networks that can detect the located lanes of vehicles, 2) it employs existing roadside/intersection cameras that can keep additional construction cost low, and 3) it establishes an innovative infrastructure for applications of next-generation Intelligent Transportation System (ITS) that can make lane level traffic control, collision avoidance, and vehicle navigation possible. With vehicular networks, the estimated positions can be broadcast to nearby vehicles. With roadside/intersection cameras, the lane positions of vehicles can be detected even if GPS is not accurate enough to provide lane-level localization. In addition, the traffic condition can be continually monitored to optimize driving efficiency for next-generation ITS. This paper demonstrates our current prototype.