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1.
IEEE Trans Cybern ; 49(9): 3432-3442, 2019 Sep.
Article in English | MEDLINE | ID: mdl-30028720

ABSTRACT

Sharing vehicle journeys with other passengers can provide many benefits, such as reducing traffic congestion and making urban transportation more environmentally friendly. For the procedure of sharing empty seats, we need to consider increased ridership and driving distances incurred by carpool detours resulting from matching passengers to drivers, as well as maximizing the number of simultaneous matches. In accordance with these goals, this paper proposes and defines the multiobjective optimization carpool service problem (MOCSP). Previous studies have used evolutionary algorithms by combining multiple objectives into a single objective through a weighted linear or/and nonlinear combination of different objectives, thus turning to a single-objective optimization problem. These single-objective problems are optimized, but there is no guarantee of the performance of the respective objectives. By improving the individual representation and genetic operation, we developed a set-based simulated binary and multiobjective carpool matching algorithm that can more effectively solve MOCSP. Furthermore, the proposed algorithm can provide better driver-passenger matching results than can the binary-coded and set-based nondominated sorting genetic algorithms.

2.
Biochem Biophys Res Commun ; 505(2): 439-444, 2018 10 28.
Article in English | MEDLINE | ID: mdl-30268498

ABSTRACT

Dihydropyrimidinase (DHPase) is a member of the cyclic amidohydrolase family, which also includes allantoinase, dihydroorotase (DHOase), hydantoinase, and imidase. Almost all of these zinc metalloenzymes possess a binuclear metal center in which two metal ions are bridged by a post-translational carbamylated Lys. Crystal structure of Tetraodon nigroviridis DHPase reveals that one zinc ion is sufficient to stabilize Lys carbamylation. In this study, we found that one metal coordination was not sufficient to fix CO2 to the Lys in bacterial DHPase. We prepared and characterized mono-Zn DHPase from Pseudomonas aeruginosa (PaDHPase), and the catalytic activity of mono-Zn PaDHPase was not detected. The crystal structure of mono-Zn PaDHPase determined at 2.23 Šresolution (PDB entry 6AJD) revealed that Lys150 was no longer carbamylated. This finding indicated the decarbamylation of the Lys during the metal chelating process. To confirm the state of Lys carbamylation in mono-Zn PaDHPase in solution, mass spectrometric (MS) analysis was carried out. The MS result was in agreement with the theoretical value for uncarbamylated PaDHPase. Crystal structure of the human DHOase domain (huDHOase) K1556A mutant was also determined (PDB entry 5YNZ), and the structure revealed that the active site of huDHOase K1556A mutant contained one metal ion. Like mono-Zn PaDHPase, oxygen ligands of the carbamylated Lys were not required for Znα binding. Considering the collective data from X-ray crystal structure and MS analysis, mono-Zn PaDHPase in both crystalline state and solution was not carbamylated. In addition, structural evidences indicated that post-translational carbamylated Lys was not required for Znα binding in PaDHPase and in huDHOase.


Subject(s)
Amidohydrolases/chemistry , Dihydroorotase/chemistry , Lysine/metabolism , Protein Carbamylation , Bacterial Proteins/chemistry , Catalytic Domain , Crystallography, X-Ray , Humans , Mass Spectrometry , Mutant Proteins/chemistry , Protein Binding , Protein Processing, Post-Translational , Pseudomonas aeruginosa/enzymology , Zinc/metabolism
3.
Nano Lett ; 17(10): 6228-6234, 2017 10 11.
Article in English | MEDLINE | ID: mdl-28926272

ABSTRACT

We demonstrated a monolithic GaN-InGaN core-shell nanorod lattice lasing under room temperature. The threshold pumping density was as low as 140 kW/cm2 with a quality factor as high as 1940. The narrow mode spacing between lasing peaks suggested a strong coupling between adjacent whisper gallery modes (WGM), which was confirmed with the far-field patterns. Excitation area dependent photoluminescence revealed that the long-wavelength lasing modes dominated the collective lasing behavior under a large excitation area. The excitation-area-dependent lasing behavior resulted from the prominent optical coupling among rods. According to the optical mode simulations and truncated-rod experiments, we confirmed that the fine-splitting of lasing peaks originated from the coupled supermodes existing in the periodic nanorod lattices. With wavelength-tunable active materials and a wafer-level scalable processing, patterning optically coupled GaN-InGaN core-shell nanorods is a highly practical approach for building various on-chip optical components including emitters and coupled resonator waveguides in visible and ultraviolet spectral range.

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