Yung-Han Chen

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The functional role of cytochrome (cyt) b(559) in photosystem II (PSII) was investigated in H22K alpha and Y18S alpha cyt b(559) mutants of the cyanobacterium Synechocystis sp. PCC6803. H22K alpha and Y18S alpha cyt b(559) mutant carries one amino acid substitution on and near one of heme axial ligands of cyt b(559) in PSII, respectively. Both mutants grew(More)
WCDMA/WLAN interworking networks are considered to support high-data-rate multimedia services and high mobility. In this paper, we propose a utility function-based access selection method (UFAS) to determine which cell is most suitable for a mobile node’s service request in heterogeneous WCDMA and WLAN networks. The UFAS method contains three parts, cells(More)
The neurotoxicity of Aβ is associated with the formation of free radical by interacting with redox active metals such as Cu(2+). However, the relationship between ion-interaction, ion-driven free radical formation, and Aβ conformation remains to be further elucidated. In the present study, we investigated the correlation of Cu(2+) interaction and(More)
We demonstrate that the steady state reaction of lysine 5,6-aminomutase with substrate analogue 4-thia-l-lysine generates a radical intermediate, which accumulates in the enzyme to an electron paramagnetic resonance (EPR) detectable level. EPR line width narrowing of approximately 1 mT due to [4'-(2)H] labeling of the pyridoxal-5'-phosphate (PLP), an(More)
Iron is essential for pathogen survival, virulence, and colonization. Feo is suggested to function as the ferrous iron (Fe(2+)) transporter. The enterobacterial Feo system is composed of 3 proteins: FeoB is the indispensable component and is a large membrane protein likely to function as a permease; FeoA is a small Src homology 3 (SH3) domain protein that(More)
We performed spectroscopic and functional characterization on cyanobacterium Synechocystis PCC6803 with mutations of charged residues of the cytoplasmic side of cytochrome (Cyt) b559 in photosystem II (PSII). All of the mutant cells grew photoautotrophically and assembled stable PSII. However, R7Eα, R17Eα and R17Lβ mutant cells grew significantly slower and(More)
We identified a spontaneously generated mutant from Synechocystis sp. PCC6803 wild-type cells grown in BG-11 agar plates containing 5 mM Glu and 10 microM DCMU. This mutant carries an R7L mutation on the alpha-subunit of cyt b559 in photosystem II (PSII). In the recent 2.9 A PSII crystal structural model, the side chain of this arginine residue is in close(More)
− The paper proposes a utility function and game theory (UGT) based network selection scheme to maximize accommodated number of calls, minimize handoff occurrence frequency, and fulfill quality of service (QoS) requirements in heterogeneous wireless networks. When a new call or a handoff call arrives, UGT would calculate the utility value and preference(More)
In this paper, admission control by a fuzzy Q-learning technique is proposed for WCDMA/WLAN heterogeneous networks with multimedia traffic. The fuzzy Q-learning admission control (FQAC) system is composed of a neural-fuzzy inference system (NFIS) admissibility estimator, an NFIS dwelling estimator, and a decision maker. The NFIS admissibility estimator(More)
The assimilatory nitrate reductase (NarB) of N(2)-fixing cyanobacterium Cyanothece sp. PCC 8801 is a monomeric enzyme with dual affinity for substrate nitrate. We purified the recombinant NarB of Cyanothece sp. PCC 8801 and further investigated it by enzyme kinetics analysis, site-directed mutagenesis, inhibitor kinetics analysis, and electron paramagnetic(More)