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Surface patterning and modification of polyurethane biomaterials using silsesquioxane-gelatin additives for improved endothelial affinity

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Science China Chemistry 2014年第4期57卷 596-604页

作者： HOU LinXi PECK Yvonne wang xiaowen wang DongAn College of Chemistry and Chemical Engineering Fuzhou University Division of Bioengineering School of Chemical and Biomedical Engineering Nanyang Technological University

Polyurethanes(PUs) are well-known for their biocompatibility but their intrinsic inert property hampers cell-matrix interactions. Surface modifications are thus necessary to widen their use for biomedical applications. In this work, surface modifications of PU were achieved first by incorporating polyhedral oligomeric silsesquioxane(POSS), followed by alteration of the surface topography via the breath figures method. Subsequently, surface chemistry was also modified by immobilization of gelatin molecules through grafting, for the enhancement of the surface cytocompatibility. Scanning electron microscopy(SEM) was used to verify the formation of highly ordered microstructures while static contact angle, FTIR and XPS confirmed the successful grafting of gelatin molecules onto the surfaces. In vitro culture of human umbilical vein endothelial cells(HUVECs) revealed that endothelial cell adhesion and proliferation were significantly enhanced on the gelatin-modified surfaces, as shown by live/dead staining and WST-1 proliferation assay. The results indicated that the combination of the strategies yielded an interface that improves cell attachment and subsequent growth. This enhancement is important for the development of higher quality biomedical implants such as vascular grafts.

关键词： biomaterials surface modification pattern polyurethane silsesquioxane gelatin endothelization

Derivation of Plastic Work Rate Done per Unit Volume for Mean Yield Criterion and Its Application

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Journal of Materials Science & Technology 2005年第4期21卷 433-436页

作者： Dewen ZHAO Yingjie XIE xiaowen wang Xianghua LIU State Key Laboratory of Rolling and Automation Northeastern University Shenyang 110004 China

In Haigh Westergaard stress space linear combination of twin shear stress and Tresca yield functions is called the mean yield （MY） criterion. The mathematical relationship of the criterion and its plastic work rate done per unit volume were derived. A generalized worked example of slab forging was analyzed by the criterion and its corresponding plastic work rate done per unit volume. Then, the precision of the solution was compared with those by Mises and Twin shear stress yield criterions, respectively. It turned out that the calculated results by MY criterion were in good agreement with those by Mises criterion.

关键词： Mean yield criterion Plastic work rate done per unit volume Functional linearization Slab forging

Study of NMR porosity for terrestrial formation in China

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Science China(Physics,Mechanics & Astronomy) 2006年第3期49卷 313-320页

作者： wang xiaowen XIAO Lizhi XIE Ranhong ZHANG Yuanzhong Faculty of Natural Resource and Information Technology China University of Petroleum Beijing 102249 China Faculty of Natural Resource and Information Technology China University of Petroleum Beijing 102249 China Faculty of Natural Resource and Information Technology China University of Petroleum Beijing 102249 China Faculty of Natural Resource and Information Technology China University of Petroleum Beijing 102249 China

NMR logging is an effective method for porosity measurement. NMR-derived porosity only comes from the pore fluid and is, in principle, not affected by rock matrix. However, it is found that the difference between NMR-derived and conventional log-derived porosities is often between 2 to 6 pu, which is unacceptable, in terrestrial formation in China. In the paper, the theory of NMR porosity was reviewed. The influence factors on NMR porosity error were analyzed based on NMR core measurements. More than 30 core samples with a wide range of porosities including sandstone, limestone and artificial ceramic were chosen for the conventional and NMR porosity measurements. The current NMR data acquisition method was studied based on laboratory NMR core meas- urements and found to be not good for terrestrial formation. A new NMR data acquisition method suiting for terrestrial formation in China was proposed and much improved the accuracy of NMR porosity measurement. It is suggested that the analysis of core samples from different regions should be carried out before logging in order to obtain accurate NMR porosity.

关键词： NMR logging,terrestrial formation,porosity

Theoretical Study on the Kinetics for the Reactions of Heptyl Radicals with Methanol

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Chemical Research in Chinese Universities 2018年第5期34卷 786-791页

作者： ZHAO Zhongrui SONG Jinou SU Boyang wang xiaowen State Key Laboratory of Engines Tianjin University Tianjin 300072 R R. China

Ab initio study of the reactions ofn-heptyl radicals（1-C7H15, 2-C7H15, 3-C7H15, and 4-C7H15） with metha- nol was conducted over the temperature range of 300--1500 K. Transition states for the reaction channels producing CTH15OH, CH3, C7H15OCH3, H, C7H16, CH2OH and CH30 were identified and the geometries of all stationary points were calculated at BB1K/MG3S level of theory. The potential barrier heights of the corresponding transition states were predicted by the CBS-QB3//BB1K and G4//BB1K methods, indicating that the eight H-abstraction channels are more kinetically favorable than the channels where OH transfers from CH3OH to C7H15 and where the CTHIsOCH3＋H products are given. Tile rate constants of H-abstraction channels were calculated with TST and TST/Eck. Both the forward and reverse rate constants have positive temperature dependence and the ttmneling effect is only important at the temperature lower than 700 K. For the reactions of H-atom abstraction from methyl in CH3OH by n-heptyl, a reverse and the corresponding forward rate constant are roughly equal. For the reactions of H-atom abstraction from OH in CH3OH by n-heptyl, a reverse rate constant is larger by several orders of magnitude thin1 the corresponding forward one.

关键词： n-Heptane Methanol Ab initio calculation Conventional transition state theory Tunneling effect

The Influencing Factors of Disposable Acetylcholinesterase Biosensor for in Situ Detection of Organophosphorus Pesticide

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稀有金属材料与工程 2006年第A3期35卷 389-391页

作者： xiaowen Xu Xiaohao wang Fei Tang Zhaoying Zhou State Key Laboratory of Precision Measurement Technology and Instruments Tsinghua University Beijing 100084 China

An amperometric biosensor based on acetylcholinesterase (ACHE) is assembled by simple adsorption of the AChE on 7,7,8,8-tetracyanoquinodimethane (TCNQ) modified screen-printed *** biosensor is used to detect the inhibitory effect of organophosphorus pesticides on AChE *** detection of organophosphorus pesticides is done with acetylthiocboline chloride (ATCh) as *** order to obtain the optimized response to substrate,the influencing factors of the biosensor are investigated,including temperature,pH,incubation time,substrate concentration and AChE concentration. The measurements were performed after inhibition by immersing the enzyme electrode into the parathion methyl solution. Under the optimized conditions,that is,500 U/ml AChE concentration,pH 7.2,10 min incubation time,2 mmol/L substrate concentration and temperature of 37℃,from 5×10^(-8) mol/L to 5×10^(-5) mol/L is close to linear (regression equation: y(%)=124.055+15.7991gx,R^2=0.99644),which corresponds to 8.7%～56.1% AChE *** the optimized conditions, the lowest detectable amount of parathion methyl is 13×10^(-9).

关键词： biosensor AChE screen-printed electrodes influencing factors organophosphorus pesticides

Chemical Stability, Ionic Conductivity of BaCe0.9-xZrxSm0.10O3-α and Its Application to Ammonia Synthesis at Atmospheric Pressure

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Chinese Journal of Chemistry 2011年第6期29卷 1114-1118页

作者： wang, xiaowen Yin, Jinling XU, Jianhong wang, Hongtao Ma, Guilin Key Laboratory of Organic Synthesis of Jiangsu Province College of Chemistry Chemical Engineering and Materials Science Soochow University Suzhou Jiangsu 215123 China

Dense ceramic samples BaCe0.9-xZrxSm0.10O3-α （x=0.10, 0.15, 0.20, 0.30） were obtained by heat-treating the precursors prepared from a coprecipitation route. The phase structure, chemical stability and conduction behaviors of the ceramic samples have been investigated by X-ray powder diffraction and alternating current impedance spectroscopy methods. All the ceramic samples displayed a single phase of orthorhombic perovskite. The samples with x ≥0.20 were relatively stable after exposed to the flowing mixed gases： CO2 （φ=3%）＋H2O （φ=3%）＋N2 （φ= 94%） at 873 K for 12 h. Among the samples tested, the sample with x=0.20 exhibited both adequate conductivity and better chemical stability. The contribution of different charged species for x=0.20 sample to the conduction in wet hydrogen atmosphere was investigated by means of gas concentration cells. It was found that the sample of x= 0.20 was almost a pure ionic conductor, and the ionic conduction was contributed mainly by proton and partially by oxide ion in wet hydrogen atmosphere at 773--1073 K. The ammonia synthesis at atmospheric pressure in an electrolytic cell based on the sample of x=0.20 was successfully conducted and the peak ammonia formation rate achieved 2.67 × 10 ^-9 molos-locm 2 with direct current of 0.80 mA at 773 K.

关键词： BaCe0.9-xZrxSm0.10O3-α chemical stability ion conduction proton transport ammonia synthesis

Disposable Amperometric Acetylcholinesterase Biosensor for the Detection of Organophosphorus Pesticides

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稀有金属材料与工程 2006年第A3期35卷 333-336页

作者： Xiaohao wang xiaowen Xu Fei Tang Zhaoying Zhou State Key Laboratory of Precision Measurement Technology and Instruments Tsinghua University Beijing 100084 China

A rapid,simple,disposable and inexpensive acetylcholinesterase (ACHE) amperometric biosensor for the detection of organophosphorus pesticides was developed by simple adsorption of the enzyme on screen-printed *** biosensor consisted of an Ag/AgCl reference electrode and a graphite working *** mixture of graphite and the 7,7,8,8-tetracyanoquinodimethane (TCNQ) was printed on *** detection of organophosphorus pesticides was done with acetylthiocholine chloride (ATCh) as *** biosensor was used to detect the inhibitory effect of organophosphorus pesticides on AChE *** 1μl of enzyme solution containing 0.1 U AChE and 1% bovine serum albumin (BSA) were simply dropped on the working electrode *** biosensor operated at a potential of 300 mV vs. Ag/AgCl in a pH 7.2 0.1 mol/L phosphate buffer and 0.1 mol/L *** obtained a calibration plot of the percentage inhibition versus the logarithm of parathion methyl concentration following an incubation time of 10 mix in parathion methyl solution. The lowest detectable amount of parathion methyl was 0.026 *** amperometric biosensor based on acetylcholinesterase was disposable and low cost (about 1 yuan RMB).

关键词： amperometric biosensor AChE screen-printed electrodes organophosphorus pesticides

Structural and mechanistic understanding of an active and durable graphene carbocatalyst for reduction of 4-nitrophenol at room temperature

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Nano Research 2015年第12期8卷 3992-4006页

作者： Huawen Hu John H. Xin Hong Hu xiaowen wang Nanotechnology Centre Institute of Textiles and Clothing The Hong Kong Polytechnic University Hong Kong SAR 999077 China

The development of an active, durable, and metal-free carbocatalyst that is able to replace metal-based catalysts is of increasing scientific and technological importance. The use of such a catalyst would avoid problems caused by metal- containing catalysts, for example, environmental pollution by heavy metals and depletion of rare metal resources. Herein, an active and durable graphene carbocatalyst is presented for the carbocatalytic conversion of 4-nitrophenol to 4-aminophenol at ambient temperature. The carbocatalyst was prepared via a mild, water-based reaction between L-ascorbic acid （AA） and graphene oxide （GO） and did not involve any other reactants. During the structure and catalytic property optimization, a series of carbocatalysts were fabricated at various reaction temperatures and AA/GO ratios. Using several characterization techniques, detailed structural features of these carbocatalysts were identified. Possible active species and sites on the carbocatalysts were also identified such as certain oxygen-containing groups, the ~x-conjugated system, and graphene sheet edges. In addition, the synergistic effect between these active species and sites on the resulting catalytic activity is highlighted. Furthermore, we clarified the origin of the high stability and durability of the optimized carbocatalyst. The work presented here aids the design of high-performance carbocatalysts for hydrogenation reactions, and increases understanding of the structural and mechanistic aspects at the molecular level that lead to high catalyst activity and durability.

关键词： metal-free graphene carbocatalyst activity and durability L-ascorbic acid active sites and domains synergistic effect carbocatalytic conversion of 4-nitrophenol (4NP) to 4-aminophenol (4AP)

Interferometric coherence and seasonal deformation characteristics analysis of saline soil based on Sentinel-1A time series imagery

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Journal of Systems Engineering and Electronics 2021年第6期32卷 1270-1283页

作者： ZHANG Rui XIANG Wei LIU Guoxiang wang xiaowen MAO Wenfei FU Yin CAI Jialun ZHANG Bo Faculty of Geosciences and Environmental Engineering Southwest Jiaotong UniversityChengdu 611756China State-Province Joint Engineering Laboratory of Spatial Information Technology of High-Speed Rail Safety Chengdu 611756China

Affected by the natural environmental and human activity factors,significant seasonal differences appear on the regional scattering characteristic and ground deformation of saline *** decorrelation due to season replacement limits the conventional multi-temporal interferometric synthetic aperture radar(MT-InSAR)technique and its application in such *** extend the monitoring capability in the salt desert area,we select a vast basin of saline soil around Howz-e-Soltan Salt Lake of Iran as the study area and present an improved MTInSAR for experimental *** on 131 C-band Sentinel-1 A images collected between October 2014 to July 2020,1896 refined interferograms in total are selected from all interferogram *** coherence analysis shows that the coherence in the saline soil area has an apparent seasonal variation,and the soil moisture affected by the precipitation may be the main factor that leads to the seasonal ***,the deformation characteristics of saline soil under different environmental conditions and human activity factors are compared and analyzed in *** deformation mechanisms of different saline soil types are initially revealed by combining interferometric coherence,meteorological data,and engineering geological characteristics of saline *** results would provide reference for the large-scale infrastructure construction engineering in similar saline soil areas.

关键词： Howz-e-Soltan Salt Lake saline soil multi-temporal InSAR interferometric coherence seasonal deformation Sentinel-1A