改性羟基磷灰石/聚乳酸复合材料制备及其生物相容性评价

针对聚乳酸(PLLA)和羟基磷灰石(HA)两者复合时界面相容性差的问题,采用硅烷偶联剂十八烷基三氯硅烷(OTS)对HA颗粒进行了表面改性,通过热诱导相分离法制备了OTS-HA/PL-LA多孔复合材料.扫描电镜结果表明,OTS-HA/PLLA多孔复合材料中改性HA颗粒的分布较均匀,PLLA和改性HA颗粒之间的界面相容性得到了改善.孔隙率测试表明,OTS-HA/PLLA多孔复合材料的孔隙率均大于90%,适合骨修复材料对孔隙率的要求.细胞培养结果表明,复合材料对骨髓间充质干细胞的生长无抑制作用,细胞在材料表面能正常黏附、生长、增殖,具有良好的细胞附着形态和细胞增殖率,表现出了良好的生物相容性.     

丝素蛋白-聚乙烯醇复合凝胶对骨组织工程支架性能的影响

组织工程骨支架材料及制备对支架性能影响至关重要。同单一聚乙烯醇凝胶相比,丝素蛋白-聚乙烯醇复合凝胶不仅可以增加支架所承受应力而且可以提高支架韧性。研究证明,使用水浴加热方法,将丝素蛋白粉末与聚乙烯醇晶粒按照1∶4混合加热,制成丝素蛋白-聚乙烯醇复合凝胶。再与羟基磷灰石充分混合,基于低温冷冻干燥技术,制备成试验试样。压缩试验测量最大压缩强度为31.2 MPa,弹性模量为11.07 MPa,最大总变形低于单一聚乙烯醇/羟基磷灰石试样,且压缩时不易发生断裂及粉碎,综合力学性能较好。电镜实验观察得到羟基磷灰石/丝素蛋白-聚乙烯醇复合材料试样孔径为15~350μm,微孔分布均匀且连通性较好。水浴加热后的丝素蛋白-聚乙烯醇(1∶4)复合凝胶与羟基磷灰石按照1.5∶1混合时,3D打印复合材料支架成形好,无丝材膨胀,孔隙明显。使用此方法制备的羟基磷灰石/丝素蛋白-聚乙烯醇复合材料,力学性能及孔径大小利于负重部位骨缺损修复及骨细胞的生长。     

仿生增强制备聚乳酸基骨组织工程复合材料

依据仿生原理制备了纳米羟基磷灰石聚乳酸(nHA-PLA)复合的骨框架材料.此复合材料中的主要成分是纳米羟基磷灰石,纳米相的羟基磷灰石就是天然骨中主要的无机相.在保持高孔隙率(90%)的同时,复合材料的抗压性能达到2.07 MPa,高于单纯的聚乳酸框架材料(为0.89 MPa).分离成骨细胞并在三维框架材料上培养,用扫描电镜进行观察,复合材料具有很好的细胞贴附性能.仿生制备的三维纳米羟基磷灰石聚乳酸复合骨框架材料,无论从结构还是性能上,都是骨组织工程中的优选材料之一.     

胶原蛋白/壳聚糖/羟基磷灰石多孔复合材料的制备与表征

从猪皮中提取胶原蛋白,并成功地制备了多孔的胶原蛋白/壳聚糖/羟基磷灰石多重复合材料.利用傅立叶红外光谱(FTIR)、紫外光谱(UV-vis)、扫描电镜(SEM)和热重分析(TGA)对胶原蛋白和复合材料进行了分析.结果表明:该方法制备的多重复合材料,其平均孔径为200nm,羟基磷灰石的含量高(43%,w/w),具有良好的生物活性和界面粘接效果.     

羟基磷灰石/聚己内酯生物复合材料的制备及其生物活性

以聚己内酯(PCL)为基底、羟基磷灰石(HA)为增强剂,采用溶液浇铸法制备HA/PCL复合材料,考察了浸渍于模拟体液(SBF)中的复合材料生物活性,并用X衍射(XRD)和傅立叶变换红外光谱(FT IR)对材料的结构和组成进行表征。结果表明:HA/PCL(wHA=0.30)复合材料在SBF中浸渍14 d后,即在其表面形成一层弱结晶的碳磷灰石(CHA)覆盖层,显示良好的生物活性。     

几种骨组织工程复合支架材料在模拟生理溶液中的生物矿化性能比较

采用生物活性玻璃(BG)、磷酸三钙(TCP)、羟基磷灰石(HA)等生物活性陶瓷与3-羟基丁酸酯-3-羟基戊酸酯的共聚物(PHBV)复合,制备了性能良好的骨组织工程支架材料,分析了PHBV/BG,PHBV/TCP,PHBV/HA三种复合多孔支架在模拟生理溶液中的一系列化学反应,以及多孔材料在模拟生理溶液中浸泡后的成分、结构和微观形貌的变化.研究结果表明,三种复合支架材料在模拟生理溶液中发生了降解反应而失重;PHBV/BG和PHBV/TCP在模拟生理溶液中还发生了生物矿化反应,在表面形成矿化沉积层,为具有骨生物活性的结晶态类骨碳酸羟基磷灰石;而PHBV/HA在模拟生理溶液中没有明显的生物活性反应.     

羟基磷灰石陶瓷诱导成骨细胞的研究

通过定量检测在羟基磷灰石(HA)表面生长的成骨细胞骨涎蛋白和骨钙蛋白的表达,研究了羟基磷灰石陶瓷对成骨细胞的影响．研究结果表明,随着成骨细胞培养时间的延长,在羟基磷灰石表面生长的成骨细胞骨钙蛋白和骨涎蛋白的表达量相对于对照组有显著增加．由于骨钙蛋白和骨涎蛋白是成骨细胞分化晚期高度表达的两种标志性蛋白质,因此其表达量的显著提高意味着羟基磷灰石陶瓷可以诱导成骨细胞的成熟。这一结果可进一步为理解HA陶瓷的生物相容性和生物活性提供分子生物学依据。     

镁合金基HA材料生物相容性及生物活性的研究

采用电泳沉积法制备了镁合金基羟基磷灰石表面涂层生物复合材料.利用动物体内埋植实验和SBF浸泡实验分别对复合材料生物相容性及生物活性进行研究.将SD大鼠分为对照组和植入组,植入一定的时间后,取植入物周围组织进行切片、HE染色和组织分析;将复合材料恒温浸泡于SBF溶液四周后取出,通过检测复合材料表面生长磷灰石的能力作为评价该材料的生物活性.实验结果是植入物周围出现组织增生,有结缔组织及新生血管的形成,未见明显的组织炎症反应,无多核的巨细胞、淋巴细胞和中性粒细胞等炎细胞的浸润;复合材料浸泡于SBF溶液后,复合材料表面形成一层类骨磷灰石.表明镁合金基羟基磷灰石生物复合材料无细胞毒性,不引起机体免疫反应,能诱导磷灰石的形成,具有良好的生物相容性及生物活性.     

温敏水凝胶/磷酸三钙生物复合材料的制备及其在小鼠体内的成骨研究

为制备温敏水凝胶/磷酸三钙生物复合材料,并检测其成骨相关性能,将温敏水凝胶在4℃下溶解,按24∶76比例加入磷酸三钙粉体,在27℃以上混合形成复合材料;通过扫描电子显微镜测试和力学性能手段对样品进行检测,然后将复合材料植入BALB/c小鼠大腿肌肉中,并设置羟基磷灰石和β-磷酸三钙对照组;术后12周,收获材料、固定、石蜡包埋、切片后进行组织学染色,观察新生骨组织的形成情况.结果显示:合成的生物复合材料均匀可控、形态规则;其具有一定不规则孔结构,孔径范围在100μm左右;术后12周,温敏水凝胶/磷酸三钙和β-磷酸三钙组均有大量新生骨组织形成,但其形成方式不同,其中β-磷酸三钙组中新骨面积百分数为(10. 47±1. 57)%,温敏水凝胶/磷酸三钙组中新骨面积百分数为(8. 30±1. 38)%,P 0. 05,两组没有明显的统计学差异;而羟基磷灰石组没有发现任何骨组织.结果表明,温敏水凝胶/磷酸三钙是一种可根据不同需要塑形成任意形状的生物复合材料,其在BALB/c小鼠体内的具有较强的骨诱导能力.     

镁表面制备羟基磷灰石涂层方法研究

镁及其合金由于具有良好的生物学特性,成为潜在的可生物降解的植入材料;但是其低的抗腐蚀能力会导致植入失败。在镁基体表面获得羟基磷灰石(HA)涂层用以改善镁及其合金的抗腐蚀能力。以硝酸钙和五氧化二磷为前躯体,使用溶胶-凝胶法制备出羟基磷灰石,并使用旋涂法在工业纯镁表面合成羟基磷灰石(HA)涂层。样品利用X射线衍射仪(XRD)、扫描电镜(SEM)进行了表征,并探讨了热处理温度对涂层的影响以及涂层的生成机理。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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