Behavior of MC3T3-E1 Osteoblast Cultured on Chitosan Modified with Polyvinylpyrrolidone

The physical and chemical properties of four kinds of modified chitosan materials made by blending chitosan with polyvinylpyrrolidone （PVP） were investigated. All four of these modified chitosan materials were hydrophilic with water contact angles ranging from 59°to 69°. Fourier transform-infrared spectra of the modified materials showed a new band at 1288 cm^-1, implying formation of a surface physical interpenetrating network structure. Enzyme linked immunosorbent assay results indicated that much less fibronectin was adsorbed on the modified materials than on only chitosan. The viability of MC3T3-E1 osteoblasts cultured on the materials was assessed by 3-（4,5-dimethyl-2-thiazolyl）-2,5-diphenyl- 2H-tetrazolium bromide assay. The results show that adding PVP10000 into the chitosan promotes adhesion of MC3T3-E1 osteoblasts on the modified materials, but has no effect on cell growth and proliferation; while adding PVP40000 reduces cell adhesion, growth, and proliferation. The results suggest that the increased hydrophilicity of the material surface does not always improve its biocompatibility, which will influence the selection and design of biomaterials.     

小学生语文学习习惯的培养

通过有选择的阅读，可以刺激学生的大脑，唤醒它、迫使它加强工作。而语文水平的高低直接与学生是否重视课外阅读有关。     

Compatibility of Chitosan-Gelatin Films with Adipose Tissue Derived Stromal Cells

Introduction Chitosan, the partially N-deacetylated form of chitin, is the second most abundant biomaterial after cellulose. Due to its biocompatibility, biodegradability, and bio- activity, chitosan and its derivant complexes have been studied in various…     

小学生语文学习习惯的培养

通过有选择的阅读,可以刺激学生的大脑,唤醒它,迫使它加强工作.而语文水平的高低直接与学生是否重视课外阅读有关.     

宁波市社区H型高血压患病率调查和危险因素分析

目的研究宁波市社区H型高血压患病率及其相关危险因素。方法2011-12-2012-01以宁波市海曙区西门、南门社区的高血压患者为研究对象,通过问卷调查、体格检查和实验室检查,采集研究对象的社会人口学特征、一般情况等,以2011年两个社区户籍人口构成计算成人H型高血压患病率,并对H型高血压的相关危险因素进行统计学分析。结果共2077例符合入选标准的高血压患者进入研究,1895例资料完整,其中男771例（40.69%）,女1124例（59.31%）;平均年龄（66.45±8.83）岁,高血压病程（10.73±8.18）年。高血压人群中H型高血压1489例,患病率78.58%,男性为91.96%,女性为69.40%。应用宁波市海曙区疾病预防与控制中心2011年末两社区18岁以上人口数统计结果进行计算,宁波市社区成人H型高血压患病率达15.41%。男性、高龄、高血压病程较长、卒中病史、高血压家族史患者的H型高血压患病率显著升高;logistic多元回归分析可见高龄、腰围、高血压家族史、吸烟、饮酒为H型高血压的独立危险因素。结论宁波市社区成人H型高血压患病率及高血压人群H型高血压患病率较高。积极控制血压、控制腰围、戒烟限酒是降低H型高血压发病率的关键。     

(3S,6S)-及(3S,6R)-3-苄氧甲基-6-甲基-吗啉-2,5-二酮的 制备及其晶体结构

以2-溴丙酸和N-叔丁氧羰基-O-苄基-L-丝氨酸为起始试剂首先制得N-(2-溴丙基)-O-苄基-L-丝氨酸(BPBS), 在N,N-二甲基甲酰胺(DMF)/三乙胺(Et3N)溶剂中80 ℃经9 h后BPBS发生分子内环化反应生成(3S,6S)-3-苄氧甲基-6-甲 基-吗啉-2,5-二酮[(3S,6S)-BMMD]及(3S,6R)-BMMD共存体, 产率70%. 将所制得的共存体以乙酸乙酯为重结晶溶剂, 采用微分重结晶法, 经4次“溶解-部分重结晶”操作循环制得两种纯光学构型的(3S,6S)-BMMD和(3S,6R)-BMMD. 将两种光学纯双手性中心的BMMD分别溶于乙酸乙酯, 室温下培养得(3S,6S)-BMMD和(3S,6R)-BMMD的单晶体, 以X射线衍射法测定上述两种BMMD的分子结构.     

Porous Chitosan Microcarriers for Large Scale Cultivation of Cells for Tissue Engineering： Fabrication and Evaluation

Introduction Regeneration of injured tissue on a man-made template has been used since the earlier 1980s[1]. Afterward, it was accepted as a tissue engineering technology[2,3]. Nowadays many kinds of damaged or dysfunctional tissues/organs such as bones, …