Aeromonas hydrophila cytosolic 5’-methylthioadenosine/S-adenosylhomocysteine nucleosidase MtaN-2

Jinli Chen,Fei Shang,Lulu Wang,Wei Liu,Yuanyuan Chen,Jing Lan,Liming Jin,Nam-Chul Ha,Chunshan Quan,Yongbin Xu 한국구조생물학회 2018 Biodesign Vol.6 No.3

5’-methylthioadenosine/S-adenosylhomocysteine nucleosidase (MTAN) plays a critical role in diverse pathways in bacterial cells such as biological methylation, polyamine biosynthesis, methionine recycling, and bacterial quorum sensing. It has been known that MtaN catalyzes the hydrolysis of N-ribosidic bond of adenosine-based substrates such as S-adenosyl-L-homocysteine (SAH), S-methyl-5’-thioadenosine (MTA) and 5’-deoxyadenosine (5’-DOA). In Aeromonas hydrophila, there are two MtnN subfamily proteins: MtaN-1, a periplasmic protein with an N-terminal signal peptide; and MtaN-2, a cytosolic protein. In this study, MtaN-2 from A. hydrophila was successfully expressed and purified using Ni-NTA affinity, Q anion-exchange, and gel-filtration chromatography. We first crystallized apo MtaN-2 but it diffracted to a low resolution of 5.1 Å. New crystals suitable for diffraction were obtained by adding 2 mM adenosine, a substrate analog of MtaN-2 during purification process and the crystals diffracted to the resolution of 2.0 Å. The crystals belong to the trigonal space group P31 or P32, with unit-cell parameters of a = b = 74.94 Å and c = 185.21 Å. The asymmetric unit contains four complexes of MtaN-2 with hydrolysis products of adenosine.

Study on the Mechanical Properties of Functional Graphene/Polyethylene Composites by Molecular Dynamics Simulation

Yuanyuan Qin,Yifei Wang,Jin Liu,Fengfeng Chen,Aiying Yao,Zhanchun Chen,Fu Junyu 한국고분자학회 2022 Macromolecular Research Vol.30 No.12

The mechanical properties of functionalized graphene/polyethylene (f- GRA/PE) composites and graphene/polyethylene (GRA/PE) composites were studied based on the crystallized models with the molecular dynamics simulation in this paper. The effects of GRA and f-GRA with different mass fractions on the mechanical properties of polyethylene were considered. The results showed that the adsorption capacity of polyethylene molecular chains of f-GRA is stronger, the compatibility of f-GRA/PE system is higher with decreasing the interface distance, and the dynamic property of molecular chain is weaker with reducing the radius of gyration of f-GRA/ PE. Furthermore, the reduction of mechanical energy consumption results in the increase of wear resistance of the system, which is more obvious when the mass fraction of f-GRA increases. Finally, the influence of different tensile rates on the composite system was studied. It was found that during the tensile process, the ability of the composite material to resist deformation in the stretching direction is enhanced, and the functionalized graphene inhibits the movement of the molecular chain due to the adsorption force, which improves the yield stress of the f-GRA/PE composite material, thereby increasing the tensile strength. Tensile rate has a certain effect on mechanical properties, and elastic modulus and yield stress increase with the increase of strain rate.

Synthesis and Gas Adsorption Properties of Carbide-Derived Carbons from Titanium Tin Carbide

Yuanyuan Zhu,Aiguo Zhou,Jin Jia,Junjun Wang,Jiang Liu,Baolin Xing,Chuanxiang Zhang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2016 NANO Vol.11 No.4

Here we reported the synthesis of nanoporous carbide-derived carbons (CDCs) from a new precursor, titanium tin carbides (Ti2SnC), via chlorination at 400–1100℃. At low chlorination temperature (400–500℃), as-synthesized CDCs mainly consisted of amorphous carbon and chlorides. As the chlorination temperature increased up to 600℃, chlorides disappeared, and the main composition of CDCs was amorphous carbon. At high chlorination temperature, there was a trend of graphitization. The microstructure of CDCs was observed and characterized by scanning electron microscopy and transmission electron microscopy. Some graphite-like sheet structures in CDCs were found. Specific surface area (SSA) and pore volume of CDCs increased with chlorination temperature, except an abnormal decrease of the CDC chlorinated at 900℃. CDC chlorinated at 1100℃ had the largest SSA, 1580 m2 /g. In order to apply these materials as novel hydrogen/methane storage media in the area of energy efficient transport, gas adsorption properties of CDCs were measured. For CDC chlorinated at 1100℃, pore volume uptakes are 206 cm3 /g at 60 bar (25℃) for methane, and ~442 cm3 /g at 35 bar (-196℃) for hydrogen, respectively. It was suggested that CDCs from Ti2SnC are promising materials for hydrogen/ methane adsorptive storage.

Q-learning Algorithm Based Multi-Agent Coordinated Control Method for Microgrids

Yuanyuan Xi,Liuchen Chang,Meiqin Mao,Peng Jin,Nikos Hatziargyriou,Haibo Xu 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

This paper proposes a Q-learning algorithm (Q-LA) based multi-agent coordinated control method for microgrids. By the method, Q-LA is adopted to calculate the power to be regulated, which is called the microgrid regulation error (MRE), in secondary control for real-time operation. And the generation schedule of distributed generators (DGs) as well as batteries is modified in real time with the MRE by the fuzzy theory and particle swarm optimization method, taking the economy and environmental benefits into consideration together. The simulation platform of Q-LA based multi-agent hybrid energy management system for microgrid (HEMS-MG) is established in C++ Builder. The simulation results verify the effectiveness and feasibility of the proposed method.

First-principles studies of K₁ ₋ _xM_xMgH₃ (M = Li, Na, Rb, or Cs) perovskite hydrides for hydrogen storage

Li, Yuanyuan,Mi, Yiming,Chung, Jin Suk,Kang, Sung Gu Elsevier 2018 International journal of hydrogen energy Vol.43 No.4

<P><B>Abstract</B></P> <P>The structural stability and hydrogen release properties of M-doped KMgH<SUB>3</SUB> (M = Li, Na, Rb, or Cs) were examined using density functional theory (DFT) calculations. The reaction enthalpies (ΔH) of the four possible dehydrogenation reaction pathways were calculated using the doped structures with different phases ( P m 3 ¯ m , P<I>nma</I>, and R3<I>c</I>). The most favorable reaction pathway among these four pathways was found. Among the dopants investigated, the most promising dopant for this reaction was Li. In addition, the application of pressure was found to be useful for tuning the reaction enthalpies of the dehydrogenation reactions. Overall, the results present an efficient means of designing new promising perovskite-type hydrides for hydrogen storage.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Perovskite-type KMgH<SUB>3</SUB> is a promising candidate for hydrogen storage. </LI> <LI> The most favorable reaction pathway of dehydrogenation reactions was examined. </LI> <LI> Li was the most useful and effective dopant to release hydrogen. </LI> <LI> Pressure can be usefully employed for tuning the reaction enthalpies of dehydrogenation reactions. </LI> </UL> </P>

Union Dyeing of the Photografted PET/Wool Blend Fabrics with Dimethylaminopropyl Methacrylamide

Dong, Yuanyuan,Lyoo, Won-Seok,Jang, Jin-Ho 한국섬유공학회 2010 FIBERS AND POLYMERS Vol.11 No.2

Dimethylaminopropyl methacrylamide (DMAPMA) was grafted onto PET/wool blend fabrics by continuous UV irradiation. Union dyeing of the photografted fabrics was investigated using three reactive dyes of ${\alpha}$-bromoacrylamide reactive groups. The influence of grafting yield, DMAPMA concentration, NaCl amount, pH value, and dyeing temperature on the dyeability was evaluated. The dyeability of both PET and wool components was improved significantly by the DMAPMA photografting and successive reactive dyeing. Although the dyeability of the PET component in the blend substantially was improved with higher grafting, equal dyeability between PET and wool was difficult to achieve due to more facile grafting and higher reactivity of the wool component compared with the modified PET component. However, the color fastness of the PET/wool blend fabric was excellent for all three colors. This study may offer a way to achieve union dyeing of PET/wool blend fabrics.

Bacillus amyloliquefaciens NAD+-dependent protein deacetylase: purification, crystallization and X-ray crystallographic analysis

Fei Shang,Jinli Chen,Lulu Wang,Yuanyuan Chen,Jing Lan,Wei Liu,Liming Jin,하남철,Chunshan Quan,Yongbin Xu 한국구조생물학회 2019 Biodesign Vol.7 No.1

Sirtuins are NAD+-dependent deacetylase that are broadly conserved throughout bacteria, archaea, and eukaryotes. Themembers of sirtuins are important in regulating diverse biological pathways, including gene silencing, DNA repair, genomestability, longevity, metabolism, and cell physiology. Sirtuin from Bacillus amyloliquefaciens (BaSrtN) is a particularlyinteresting bacterial Sir2 homologue. In this study, to further understand the function and mechanisms of this protein,BaSrtN was successfully expressed and purified using Ni-NTA affinity, Q anion-exchange, and gel-filtration chromatography. Purified BaSrtN was crystallized and diffracted to the resolution of 1.45 Å. The preliminary crystallographic analysissuggested that BaSrtN crystal belongs to the trigonal space group P31 or P32, with unit-cell parameters of a = b = 90.115and c = 86.306 Å. Size-exclusion chromatography suggested that BaSrtN prefer to exit as monomers in solution.

Multiple frequency vibration of the micro lubricating gap geometry between cylinder block and valve plate in an axial piston pump

Zhiqiang Zhang,Yuanyuan Chen,Jianli Song,Kunshan Jin,Haibo Zhou 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.11

Refined models of the forces in the cylinder block/valve plate system along Z axis and the moments around X and Y axes were built, considering the pressure ripple due to the piston reciprocating motions (PRM) and pressure variations in the wedge film (PVF) and the chambers (PVC) caused by the silencing slots. The multi-frequency vibration models of the gap geometry owing to the forces and moments are proposed. The dynamic mechanical balance equations are presented. The frequency spectra of the test gap thickness show the vibration amplitudes at the first three frequencies are larger than those of the other frequencies. PVF and PVC have obvious influences on the gap at the second frequency, and PRM exerts an impact at the third. The moment fluctuations around X and Y axes, bending stiffness of the shaft, and the rough surfaces contact could affect the vibration amplitude of the wedge gap geometry.

Caption Region Detection in Video Images by Improved Corner Detector

Xin Liu,Jin Dai,Yuanyuan Jia,Rubin Liu 보안공학연구지원센터(IJSIP) 2014 International Journal of Signal Processing, Image Vol.7 No.4

Surface modification of co-doped reduced graphene oxide through alkanolamine functionalization for enhanced electrochemical performance

Khandelwal, Mahima,Li, Yuanyuan,Hur, Seung Hyun,Chung, Jin Suk The Royal Society of Chemistry 2018 NEW JOURNAL OF CHEMISTRY Vol.42 No.2

<P>This manuscript presents the facile synthesis of alkanolamine functionalized N,S co-doped reduced graphene oxide (NSrGO) using thiamine hydrochloride as a reducing and co-doping agent for N and S, and triethanolamine (TEA) as a functionalizing agent. The functionalization of TEA molecules on N,S co-doped rGO (TEA-NSrGO) was confirmed by FTIR and XPS analyses. Chemical functionalization of TEA on the surface of NSrGO minimizes restacking of the co-doped sheets and results in an enhanced surface area, as was evidenced by FESEM, TEM, and BET measurements. Moreover, the formation of oxygen-containing groups on NSrGO <I>via</I> covalent functionalization of TEA molecules effectively tunes the surface chemistry of NSrGO, making the electrode material accessible to electrolyte ions. Interestingly, the synergistic effect of TEA functionalization and co-doping in rGO results in impressive electrochemical performance, with a high specific capacitance value of 363 F g<SUP>−1</SUP> at 20 A g<SUP>−1</SUP>, outstanding cycling stability (91% retention after 10 000 cycles at 20 A g<SUP>−1</SUP>), high coulombic efficiency (99.5-100%), and high energy/power density (31.86 W h kg<SUP>−1</SUP>/7646 W kg<SUP>−1</SUP>). These electrochemical features suggest the potential of this electrode material for energy storage applications.</P>