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Conjugation of a zwitterionic polymer with dimethyl chains to lipase significantly increases the enzyme activity and stability

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Chinese Journal of Chemical Engineering 2022年第7期35卷 48-53页

作者： chunyu zhang Yan Sun Xiaoyan Dong Department of Biochemical Engineering School of Chemical Engineering and Technology and Key Laboratory of Systems Bioengineering and Frontiers Science Center for Synthetic Biology(Ministry of Education)Tianjin UniversityTianjin 300350China College of Life Sciences Yantai UniversityYantai 264005China

Enzyme-polymer conjugates are complex molecules with great practical *** work was designed to develop a novel enzyme-polymer conjugate by covalently coupling a zwitterionic polymer with side dimethyl chains(pID)to Candida rugosa lipase(CRL)via the reaction between the anhydrides of polymer chains with the amino groups of the *** resulting two CRL-pID conjugates with different pID grafting densities were investigated in term of the catalytic activity,stability and structural *** comparison with native CRL,both the CRL conjugates displayed 2.2 times higher activity than the native enzyme,and showed an increase in the maximum reaction rate(V_(max))and a decrease in the Michaelis constant(K_(m)),thus resulting in about three-fold increases in the catalytic efficiency(k_(cat)/K_(m)).These are mainly attributed to the activation of lipase by the hydrophobic alky side ***,the thermostability and pH tolerance of the lipase conjugates were significantly enhanced due to the stabilizing effect of the zwitterion *** instance,a five-fold increase of the enzyme half-life at 50℃ for the high-pID conjugated CRL was *** studies reveal that the pID conjugation protected the enzyme in the changes in its microenvironment and conformation,well correlating with enhanced activity and stability of lipase *** findings indicate that enzyme conjugation to the zwitterionic polymer is promising for improving enzyme performance and deserves further development.

关键词： Lipase Zwitterionic polymer Enzyme-polymer conjugate Stability Interfacial activation

Zwitterionic polymer-coated porous poly(vinyl acetate–divinyl benzene)microsphere: A new support for enhanced performance of immobilized lipase

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Chinese Journal of Chemical Engineering 2020年第1期28卷 242-248页

作者： Yifeng Li chunyu zhang Yan Sun Department of Biochemical Engineering and Key Laboratory of Systems Bioengineering(Ministry of Education) School of Chemical Engineering and TechnologyTianjin UniversityTianjin 300354China

Enzyme immobilization has attracted great attention for improving the performance of enzymes in industrial *** work was designed to create a new support for Candida rugosa lipase(CRL)immobilization.A porous poly(vinyl acetate–divinyl benzene)microsphere coated by a zwitterionic polymer,poly(maleic anhydride-alt-1-octadecene)and N,N-dimethylethylenediamine derivative,was developed for CRL immobilization via hydrophobic *** catalytic activity,reaction kinetics,stabilities and reusability of the immobilized CRL were *** demonstrated the success of the zwitterionic polymer coating and subsequent CRL immobilization on the porous *** immobilized lipase(p2-MS-CRL)reached27.6 mg·g^-1 dry carrier and displayed a specific activity 1.5 times higher than free *** increase of Vmax and decrease of Kmwere also observed,indicating the improvement of catalytic activity and enzyme-substrate affinity of the immobilized ***,p2-MS-CRL exhibited significantly enhanced thermal stability and pH *** improved performance was considered due to the interfacial activation regulated by the hydrophobic interaction and stabilization effect arisen by the zwitterionic polymer *** study has thus proved the advantages of the zwitterionic polymer-coated porous carrier for lipase immobilization and its potential for further development in various enzyme immobilizations.

关键词： Biocatalysis Lipase immobilization Zwitterionic polymer Hydrophobic binding Interfacial activation Stabilization

Research of robust adaptive trajectory linearization control based on T-S fuzzy system

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Journal of Systems Engineering and Electronics 2008年第3期19卷 537-545页

作者： Jiang Changsheng zhang chunyu Zhu Liang College of Automation Nanjing Univ. of Aeronautics and Astronautics Nanjing 210016 P. R. China National Key Laboratory of Fire Control Technology Luoyang 471009 P. R. China

A robust adaptive trajectory linearization control （RATLC） algorithm for a class of nonlinear systems with uncertainty and disturbance based on the T-S fuzzy system is presented. The unknown disturbance and uncertainty are estimated by the T-S fuzzy system, and a robust adaptive control law is designed by the Lyapunov theory. Irrespective of whether the dimensions of the system and the rules of the fuzzy system are large or small, there is only one parameter adjusting on line. Uniformly ultimately boundedness of all signals of the composite closed-loop system are proved by theory analysis. Finally, a numerical example is studied based on the proposed method. The simulation results demonstrate the effectiveness and robustness of the control scheme.

关键词： nonlinear system trajectory linearization control robust adaptive control T-S fuzzy system.

Fabrication and characterization of epoxylated zwitterionic copolymergrafted silica nanoparticle as a new support for lipase immobilization

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Chinese Journal of Chemical Engineering 2020年第4期28卷 1129-1135页

作者： Ning Chen chunyu zhang Xiaoyan Dong Yan Sun Department of Biochemical Engineering and Key Laboratory of Systems Bioengineering(Ministry of Education) School of Chemical Engineering and TechnologyTianjin UniversityTianjin 300354China

Our previous work proved that the thermal stability of Candida rugosa lipase(CRL)immobilized on zwitterionic polymer(poly(carboxybetaine methacrylate))grafted silica nanoparticle(SNP)was much higher than that on poly(glycidyl methecrylate)(pGMA)grafted SNP,while the latter showed significantly increased *** by the research,we have herein proposed to synthesize copolymers of zwitterionic sulfobetaine methacrylate(SBMA)and GMA for CRL *** copolymers were grafted onto SNP surface at three GMA/SBMA(G/S)molar ratios(G100/S0,G50/S50,G10/S90),followed by the covalent coupling of CRL to the surface *** immobilized CRLs on the corresponding supports were denoted as p(G100-S0)-CRL,p(G50-S50)-CRL and p(G10-S90)-*** enzyme loading increased with the increase of GMA content in the copolymer,while the activity varied with the grafted copolymer *** study proved the improvement of enzyme-substrate affinity after *** comparison to p(G100-S0)-CRL,p(G50-S50)-CRL and p(G10-S90)-CRL presented remarkably enhanced thermal stability and pH tolerance,and p(G10-S90)-CRL showed the highest *** results suggest that the copolymer design is promising for development as a versatile platform for enzyme immobilization.

关键词： Lipase Immobilization Zwitterionic copolymer Interfacial activation Stabilization

Drivers of tree demographic trade-offs in a temperate forest

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Forest Ecosystems 2022年第4期9卷 475-482页

作者： Jianghuan Qin chunyu Fan Yan Geng chunyu zhang Xiuhai Zhao Lushuang Gao Research Center of Forest Management Engineering of State Forestry and Grassland Administration Beijing Forestry UniversityBeijing100083China

Background: The demographic trade-offs(i.e. growth and survival) play important roles in forest dynamics and they are driven by multiple factors, including species’ inherent life-history strategies(such as shade-tolerance and mycorrhizal type), neighborhood interactions(such as conspecific negative density dependence, CNDD), and abiotic environment pressures. Although studies found that CNDD occurred in tropical and temperate forest,attempts to identify how the variations in CNDD control their impacts on growth and survival remain debate. In the present study, we conducted an extensive field survey, and analyzed demographic rates from 24 co-occurring temperate tree species, in order to test the importance of CNDD in shaping the growth-survival ***: Our study found that density dependence and environmental filtering were strong predictors for individual growth-survival trade-offs, while they showed variations across shade-intolerant and ectomycorrhizal species, as well as saplings and juveniles with more negative CNDD. Species growth showed positive relationship with mortality. And our results also support the fact that CNDD drives species growth-survival trade-offs at the community level with environmental ***: Our study indicates that biotic interactions such as density dependence and environment filtering played an important role in growth-survival trade-offs, and confirmed that the Janzen-Connell hypothesis in temperate forest was associated with species life-history strategies. In addition, shade-tolerance, mycorrhizal type and life-stage of forest species responded differently to CNDD, thus providing insights regarding different community assembly mechanisms and their interactions. Therefore, it is important to take species survival with growth and species life-history strategies into account when focusing on forest dynamics.

关键词： Tree survival Density dependence Growth-survival trade-offs Life-history strategy Temperate forest

Morphology and Properties of PP In-reactor Alloys Prepared with a MgCl2/TiCl4/Diisobutyl Phthalate/Phosphate Tris-methylphenyl Ester Catalyst System

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Chemical Research in Chinese Universities 2018年第1期34卷 145-150页

作者： zhang chunyu DONG Bo zhang Hexin HU Yanming zhang Xuequan Key Laboratory of Synthetic Rubber of Chinese Academy of Sciences Changchun Institute of Applied Chemistry Chinese Academy of Sciences Changchun 130022 P. R. China

A series of polypropylene（PP）/poly（ethylene-co-propylene） in-reactor alloys with different ethylene contents was prepared through a two-stage polymerization process using a MgCl2/TiCl4/diisobutyl phthalate/phosphate tris-methylphenyl ester catalyst system. The ethylene content, particle shape, fractured surface, and glass-transition temperature（Tg） of the obtained PP in-reactor alloys were characterized by means of nuclear magnetic resonance, scanning electron microscopy（SEM）, and dynamic mechamcal analysis（DMA）. The ethylene content of the PP alloys increased from 2.34% to 26.69% when the propylene/ethylene feed ratio was increased from 66/34 to 54/46（molar ratio）. Morevoer, the increment in ethylene content increased the notched Izod impact strength of the resulting PP alloys. The impact strength of the PP alloy with an ethylene content of 26.69% was 55.8 kJ/m^2, which is 12.7 times that of isotactic polypropylene. The results of DMA and SEM analysis reveal that ethylene-propylene random copolymer（EPR） in the PP alloy has a low Tg of ca. -50℃ and a high interface compatibility with the PP matrix. The excellent impact performance of the PP alloy can be attributed to the uniform dispersal of EPR in the alloy particles and PP matrix.

关键词： Polypropylene m-reactor alloy Phosphate Ziegler-Natta catalyst Ethylene-propylene random copolymer Toughening mechanism

Research status and challenges in the manufacturing of IR conformal optics

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Defence Technology（防务技术） 2024年第10期40卷 154-172页

作者： Jianbo Zhao Sheng Wang chunyu zhang Jinhu Wang Qingliang Zhao Center for Precision Engineering School of Mechatronics EngineeringHarbin Institute of TechnologyHarbin 150001China Laser Fusion Research Center China Academy of Engineering PhysicsMianyang 621900China Ultra-precision Machining Center College of Mechanical EngineeringZhejiang University of TechnologyHangzhou 310014China

The infrared conformal window is one of the most critical components in *** windows with high performance bring low aberrations,high aerodynamic performance,reliability in extreme working environments,and added value for *** the past decades,remarkable advances have been achieved in manufacturing technologies for conformal windows,where the machining accuracy approaches the nanometer level,and the surface form becomes more *** advances are critical to aircraft development,and these manufacturing technologies also have significant reference values for other directions of the ultra-precision machining *** this review,the infrared materials suitable for manufacturing conformal windows are introduced and compared with insights into their *** remarkable advances and concrete work accomplished by researchers are *** challenges in manufacturing conformal windows that should be faced in the future are discussed.

关键词： Conformal optics Window and dome Infrared material Ultra-precision grinding Polishing Measurement

Research on pavement cracking possibility based on the load mechanical response

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Science China(Technological Sciences) 2023年第12期66卷 3549-3561页

作者： WANG Meng LI ShuCai LIU RenTai zhang chunyu ZHU ZhiJing zhang LianZhen BAI JiWen School of Civil Engineering Geotechnical and Structural Engineering Research CenterShandong UniversityJinan 250061China College of Pipeline and Civil Engineering China University of Petroleum(East China)Qingdao 266580China

Cavities under roads are one of the main reasons for early structural damage to pavements. It is necessary to conduct a structural analysis of road sections with cavities and evaluate the possibility of pavement cracking caused by different cavity sizes. In this study, an analysis method for evaluating the possibility of pavement cracking based on the load-mechanical response is *** example library of the mechanical response of asphalt concrete(AC) pavements was established by numerical *** on the tensile cracking characteristics of pavements in the mechanical response research, the tensile strain at the bottom of the AC layer was selected as the key analysis parameter. Sensitivity analysis of the tensile strain was conducted, and the main factors controlling pavement cracking were determined. A tensile strain response prediction model was established using multiple linear regression, and its reliability was verified. The cavity influence coefficient(CIC) and pavement cracking factor(PCF) were constructed to analyze the cracking possibility. The variation in PCF with the cavity size and pavement structure parameters was studied. A quantitative relationship between the depth and length of the cavity for a given PCF was *** law conforms to a power function. The possibility of pavement cracking can be determined by measuring the cavity *** to the existing cavity management system, the proposed method provided analysis results of the cracking possibility that were more consistent when the cavity depth was small and the length was long. The findings of this study provide new insights for evaluating the possibility of pavement cracking.

关键词： pavement cracking cavity case base traffic load mechanical response risk analysis

NF-YCs modulate histone variant H2A.Z deposition to regulate photomorphogenic growth in Arabidopsis

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Journal of Integrative Plant Biology 2021年第6期63卷 1120-1132页

作者： chunyu zhang Qian Qian Xiang Huang Wenbin zhang Xu Liu Xingliang Hou Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement&Guangdong Provincial Key Laboratory of Applied Botany South China Botanical GardenThe Chinese Academy of SciencesGuangzhou 510650China Center of Economic Botany Core Botanical GardensThe Chinese Academy of SciencesGuangzhou 510650China College of Life Sciences University of the Chinese Academy of SciencesBeijing 100049China

Inplants,lightsignalstriggeraphotomorphogenic program involving transcriptome changes, epigenetic regulation, and inhibited hypocotyl elongation. The evolutionarily conserved histone variant H2 A.Z, which functions in transcriptional regulation, is deposited in chromatin by the SWI2/SNF2-RELATED 1 complex(SWR1 c). However, the role of H2 A.Z in photomorphogenesis and its deposition mechanism remain unclear. Here, we show that in Arabidopsis thaliana, H2 A.Z deposition at its target loci is induced by light irradiation via NUCLEAR FACTOR-Y, subunit C(NF-YC) proteins, thereby inhibiting photomorphogenic growth. NF-YCs physically interact with ACTIN-RELATED PROTEIN6(ARP6), a key component of the SWR1 c that is essential for depositing H2 A.Z, in a lightdependent manner. NF-YCs and ARP6 function together as negative regulators of hypocotyl growth by depositing H2 A.Z at their target genes during photomorphogenesis. Our findings reveal an important role for the histone variant H2 A.Z in photomorphogenic growth and provide insights into a novel transcription regulatory node that mediates H2 A.Z deposition to control plant growth in response to changing light conditions.

关键词： Arabidopsis light hypocotyl elongation NF-YC ARP6 H2A.Z deposition