检索结果-南通市图书馆

Science China(Technological Sciences) 2024年第4期67卷 1160-1169页

作者： NIU QingJing GAO ShuHui ZHU KongYing ren lixia YUAN XiaoYan School of Materials Science and Engineering Tianjin Key Laboratory of Composite and Functional MaterialsTianjin UniversityTianjin 300350China Analysis and Measurement Center Tianjin UniversityTianjin 300072China

Cryopreservation plays an essential role in biobanking and cell therapy,but the physiological toxicity of traditional cryoprotectants such as glycerol and dimethyl sulfoxide(DMSO)has raised safety issues for biomedical ***,a nonreducing disaccharide that accumulates in desiccation-or cold-tolerant organisms,has been considered as a biocompatible ***,a naturally occurring membrane-active cationic peptide,melittin,was utilized to facilitate membraneimpermeable trehalose entry into cells for effective cell ***(ethylene glycol)and poly(vinyl pyrrolidone)were applied as macromolecular protectants to improve the stabilization of cell *** the optimal protocol,the postthaw recovery of human red blood cells in freezing bags at a hematocrit of~50%could achieve 82.9%with favorable cell morphologies and physiological ***,the cryosurvival of L929 fibroblasts reached 84.3%compared to the conventional method using 10%(v/v)*** short,this work by using trehalose and melittin provides a biocompatible solvent-free approach for long-term cryostorage of cells.

关键词： melittin intracellular trehalose membrane stabilization macromolecular protectants cell cryopreservation

同方期刊数据库

Development of L-arginine-based poly(ester urethane)urea for enhanced vascular adaptability

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2022年第11期65卷 2751-2762页

作者： BAI Shan ZHANG XiangYu ZANG LeiLei ren lixia YUAN XiaoYan School of Materials Science and Engineering Tianjin Key Laboratory of Composite and Functional MaterialsTianjin UniversityTianjin300350China

Mismatched biomechanical properties between artificial vascular grafts and native blood vessels can result in intimal hyperplasia,especially for the implantation of small-diameter blood *** biomaterials for vascular repair still remain *** poly(ε-caprolactone)(PCL)has been applied for the preparation of electrospun vascular grafts,but more efforts are needed to improve its compliance with tissue ***,L-arginine-based poly(ester urethane)urea(PEUU)with both elasticity and biodegradability was synthesized so as to enhance the biomechanical properties of vascular grafts by blending electrospinning with PCL in a given mass *** was exhibited that the prepared electrospun PCL/PEUU fibrous membranes were suitable for cell proliferation with normal cell *** importantly,the electrospun membrane with 1/1 mass ratio of PCL/PEUU(PEUU50)showed specific flexibility,exhibiting more suitable mechanical properties matching to the native blood ***,the PEUU50 electrospun membrane demonstrated significantly lower Young’s modulus(9.3±0.8 MPa)and tensile strength(6.0±0.5 MPa),and extremely higher elongation(389%±24%)in wet state than those(16.3±3.0 MPa,11.4±7.1 MPa and 196%±57%,respectively)of the pristine PCL ***,this study demonstrated the great potential of amino acid-based PEUUs for the application in small-diameter vascular grafts.

关键词： poly(ester urethane)urea poly(e-caprolactone) electrospinning vascular grafts mechanical properties

Spatio-temporal differentiation of landscape ecological niche in western ecological frangible region： A case study of Yan＇an region in northwestern China

在线全文

学校读者我要写书评

暂无评论

Journal of Geographical Sciences 2007年第4期17卷 479-486页

作者： ren Zhiyuan WANG lixia College of Tourism and Environmental Sciences Shaanxi Normal University Xl＇an 710062 China

In this study, we attempt to put forward a conception of landscape ecological niche, enlightened by international scholars on extending the ecological niche theory from spatial niche to functional niche. That is helpful for comprehensively appraising landscape spatial patterns and ecological functions, also, presents a new method for analyzing landscape features from multidimensional aspects. The practice process is demonstrated by taking Yan＇an region in northwestern China as a case. Firstly, the indices system including spatial attribute and functional attribute is established for assessing landscape ecological niche. Additionally, two-dimensional figures are drawn for comparing the spatio-temporal features of landscape ecological niche in 1987 and 2000 among the 13 administrative counties. The results show that from 1987 to 2000, towards Yan＇an region, spatial attribute value of landscape ecological niche changes from 1.000 to 1.178 with an obvious increment, and functional attribute value changes from 0.989 to 1.069 with a little increment, both of which enhance the regional landscape ecological niche. Towards each county, spatial attribute value of landscape ecological niche increases to different extent while functional attribute value changes dissimilarly with an increment or a decrement.

关键词： Yah'an region landscape ecological niche spaflo-temporal differentiation

Spatial-temporal differences in in-stream flow requirement based on GIS： A case study of Yan＇an region, northern Shaanxi

在线全文

学校读者我要写书评

暂无评论

Journal of Geographical Sciences 2008年第1期18卷 107-114页

作者： WANG lixia ren Zhiyuan College of Tourism and Environmental Sciences Shaanxi Normal University Xi＇an 710062 China

Although water has the central function of the bloodstream in the biosphere especially in arid or semi-arid regions such as Yah＇an region in northwestern China, yet the very limited attention is paid to the role of the water-related processes in ecosystem. In this research, based on continuous nearly 50-year data including runoff volume, sediment discharge as well as sediment accretion from hydrographic stations, and 10-year information of water quality from pollution monitoring stations, the method for measuring in-stream flow requirement has been put forward supported by experiential models and GIS spatial analysis. Additionally, the changes of in-stream flow requirement for environment and economic development have been addressed from spatial-temporal dimensions. The results show that：（1） According to the central streams in Yan＇an region, mean annual in-stream flow requirement reaches 1.0619 billion m^3, and the surface water for economic exploitation is 0.2445 billion m3 （2） Mean annual in-stream flow requirement for sediment transfers in flood period occupies over 80% of the integrated volume in a year. （3） From the 1950s to 1970s, in-stream flow requirement for sediment transfers is comparatively higher, while from the 1980s to 1990s, this requirement presents a decreasing tendency.

关键词： GIS spatial analysis Yan'an region in-stream flow requirement spatial-temporal differences

Ceiling Degree of Polymerization for Brush Polymers Prepared via ROMP of Poly（tert-Butyl Acrylate） Macromonomers

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2018年第5期34卷 828-832页

作者： QIAO Yaping YUAN Xiaoyan ZHAO Yunhui ren lixia School of Materials Science and Engineering Tianjin Key Laboratory of Composite and Functional Materials Tianjin University Tianjin 300072 P. R. China

Controlled preparation of brush polymers is important in the design of functional materials. In this study, poly（tert-butyl acrylate） macromonomers functionalized with norbornenyl end group（NB-PtBA） were synthesized via atom transfer radical polymerization in three different molecular weights, 2000（NB-PtBA-2k）, 3000（NB-PtBA-3k）, and 8000（NB-PtBA-8k）. Additionally, brush polymers with PtBA as side chains were synthesized via ring-opening metathesis polymerization（ROMP）. Kinetic studies on ROMP of NB-PtBA showed that there was a ceiling degree of polymerization（CDP） for the brush polymers, beyond which the polymerization of NB-PtBA was out of control. For brush polymers of P[NB-PtBA-2k] and P[NB-PtBA-3k], CDPs were estimated to be ca. 400, but the value of P[NB-PtBA-8k] was ca. 100. Therefore, the controlled ROMP of brush polymers was critical at the CDP limit with increased macromonomer molecular weight.

关键词： Ring-opening metathesis polymerization Macromonomer Brush polymer Ceiling degree of polymeriza- tion Kinetics study

From Polymerization Inhibition to Controlled Ring-Opening Metathesis Polymerization of Macromonomers with Tertiary Amine Groups:The Effect of Spacer Chain

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 2021年第7期39卷 1927-1935页

作者： Tengda Zhao Kongying Zhu Xiaoliang Yu Xiaoyan Yuan lixia ren School of Materials Science and Engineering Tianjin Key Laboratory of Composite and Functional MaterialsTianjin UniversityTianjin300350 China Analysis and Measurement Center Tianjin UniversityTianjin300072 China

Main observation and conclusion Ring-opening metathesis polymerization(ROMP)is a powerful toolbox in preparation of bottlebrush polymers for its high ***,the ROMP of macromonomers with repeating tertiary amine groups,... 详细信息

关键词： Bottlebrush polymers Metathesis Polymerization inhibition Ring-opening polymerization Amines

Combination of hydrophobically modified γ-poly(glutamic acid)and trehalose achieving high cryosurvival of RBCs

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2021年第4期64卷 806-816页

作者： ZHANG QiFa LIU Bo CHONG JingHui ren lixia ZHAO YunHui YUAN XiaoYan School of Materials Science and Engineering Tianjin Key Laboratory of Composite and Functional MaterialsTianjin UniversityTianjin 300350China Tianjin Blood Center Tianjin 300110China

Trehalose is expected to be an alternative for toxic glycerol as a biocompatible cryoprotectant of red blood cells(RBCs).In this work,γ-poly(glutamic acid)(PGA)is modified by grafting hydrophobic phenethylamine,3,4-dimethoxyphenylethylamine and dodecylamine,*** graft-modified PGA can significantly enhance cryosurvival of RBCs in combination with *** of dynamic light scattering,hemolysis assay,atomic force microscope and confocal laser scanning microscope suggest that the modified PGA polymers can self-assemble into nanoparticles in phosphate buffer saline solutions at the pH range of 6.0–7.4,and exhibit membrane-disruptive activity due to hydrogen bond,conjugation and hydrophobic interactions with cell *** is assumed that the modified PGA polymers can improve the cryosurvival of RBCs by promoting membrane permeability of *** the three graft-modified polymers,phenethylamine-grafted PGA(PGA-g-PEA)can significantly increase the intracellular trehalose-loading content to 11.3±2.4 m M at pH 7.4,much higher than the value0.17±0.66 m M when trehalose is used without any *** view of the aforementioned merit,the cryosurvival rate of sheep RBCs is increased to about 90%by incubation with 1.0 mg mL-1 PGA-g-PEA and 0.36 M *** vitro cell culture of L929 fibroblasts demonstrates low cytotoxicity of ***,hydrophobic PEA-modified PGA with enhanced intracellular trehalose-loading ability can be potentially applied in glycerol-free RBC cryopreservation or other related biomacromolecule delivery systems.

关键词： γ-poly(glutamic acid) membrane-disruptive activity trehalose cryosurvival red blood cells

Antifogging and antibacterial properties of amphiphilic coatings based on zwitterionic copolymers

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2021年第4期64卷 817-826页

作者： ZHAO ChiXu YUAN XiaoYan BAI Shan SUN PingChuan ZHAO YunHui ZHU KongYing ren lixia LI XiaoHui School of Materials Science and Engineering Tianjin Key Laboratory of Composite and Functional MaterialsTianjin UniversityTianjin 300350China Key Laboratory of Functional Polymer Materials of the Ministry of Education and College of Chemistry Nankai UniversityTianjin 300071China Analysis and Measurement Center Tianjin UniversityTianjin 300072China

Tackling fogging and microbial infection problems related to the endoscope lens remain challenges due to visual disturbances and bacterial threats to human ***,highly transparent antifogging and antibacterial coatings were developed in a facile way by thermal curing of zwitterionic copolymers poly(n-butyl methacrylate-co-2-aminoethyl methacrylate-co-sulfobetaine methacrylate)s with 1,3,*** of surface chemical composition and wettability suggested that the copolymer coatings exhibited amphiphilicity with a hydrophobic surface and internal *** prepared amphiphilic coating exhibited excellent antifogging properties both in vivo and in *** introduction of hydrophobic n-butyl methacrylate and cationic aminoethylmethacrylate could improve the stability and antibacterial capability of the *** growth inhibition rates of the coatings against Staphylococcus aureus and Escherichia coli were up to 99%and the copolymer coatings with the zwitterionic groups had low hemolytic rates less than 3%.The amphiphilic copolymer coatings combined antifogging and antibacterial properties may have a promising potential for applications in biomedical devices.

关键词： zwitterionic copolymer amphiphilic coating antifogging antibacterial property hemolysis

PNDC-b-PNTPE自组装制备兼具结构色和荧光色的薄膜

在线全文

学校读者我要写书评

暂无评论

高等学校化学学报 2023年第11期44卷 167-172页

作者：段小丽韩慧敏赵明坤任丽霞鲁东大学化学与材料科学学院烟台264025 天津大学材料科学与工程学院天津300072

设计合成了含有聚集诱导发光四苯乙烯基的大位阻单体四苯乙烯基降冰片烯(NTPE),通过NTPE与含有双癸烷基的树状单体对苯二甲酸癸烷苯酯基降冰片烯(NDC)的顺序开环易位聚合(ROMP)制备具有聚集诱导发光性质的大位阻树状嵌段聚合物(PNDC-b-P... 详细信息

设计合成了含有聚集诱导发光四苯乙烯基的大位阻单体四苯乙烯基降冰片烯(NTPE),通过NTPE与含有双癸烷基的树状单体对苯二甲酸癸烷苯酯基降冰片烯(NDC)的顺序开环易位聚合(ROMP)制备具有聚集诱导发光性质的大位阻树状嵌段聚合物(PNDC-b-PNTPE).利用薄膜自组装制备了兼具结构色和荧光色的一维光子晶体薄膜.结果表明,PNDC-b-PNTPE在四氢呋喃(THF)中随着溶剂的挥发而快速自组装成为蓝色的一维光子晶体薄膜,其最大反射波长(λ_(max))为443 nm.一维光子晶体薄膜的横截面扫描电子显微镜照片表明,PNDC-bPNTPE组装为周期为133 nm的层状结构.荧光发射光谱分析结果表明,一维光子晶体薄膜在368 nm波长紫外光的激发下能够发射最大波长为425 nm的荧光.该兼具结构色和荧光色的薄膜在防伪和显示方面有潜在的应用前景.

关键词：嵌段共聚物自组装一维光子晶体聚集诱导发光

在线全文

学校读者我要写书评

暂无评论

矩形回路铅铋自然循环稳定性研究

核动力工程 2023年第S01期44卷 62-68页

作者：王欣匡波王舒婷胡文军任丽霞中广核研究院有限公司广东深圳518031 上海交通大学核科学与工程学院上海200240 中国原子能科学研究院北京102413

为了对矩形回路铅铋自然循环流动稳定性进行分析,得到影响自然循环流动的因素及其作用规律,采用时域法,开发一维系统程序FRTAC对铅铋自然循环进行数值计算,分析处理动态时序判定其稳定特性,获得了铅铋自然循环在相关工况条件下的稳定域... 详细信息

为了对矩形回路铅铋自然循环流动稳定性进行分析,得到影响自然循环流动的因素及其作用规律,采用时域法,开发一维系统程序FRTAC对铅铋自然循环进行数值计算,分析处理动态时序判定其稳定特性,获得了铅铋自然循环在相关工况条件下的稳定域与稳定性边界、铅铋自然循环回路的流动稳定性特性,以及影响因素与规律。研究表明,增大回路加热段长度会使系统的稳定性增强,而增大流道直径以及冷热段心位差均会使系统稳定性裕量降低,稳定性减弱。

关键词：铅铋自然循环稳定性时域法快堆瞬态分析程序(FRTAC)