Preparation of biomedical Ag incorporated hydroxyapatite/titania coatings on Ti6Al4V alloy by plasma electrolytic oxidation

Nano-Ag incorporated hydroxyapatite/titania(HA/TiO2) coatings were deposited on Ti6Al4V substrates by the plasma electrolytic oxidation process. Compared with the substrate, the deposited coatings display attractive mechanical and biomedical properties. First, the coatings have stronger wear resistance and corrosion resistance. Second, they show a strong antibacterial ability. The mean vitality of the P. gingivalis on the coating surfaces is reduced to about 21%.Third, the coatings have good biocompatibility. The mean viability of the fibroblast cells on the coating surface is increased to about 130%. With these attractive properties, Ag incorporated HA/TiO2 coatings may be useful in the biomedical field.     

硒蛋白M及其与重大疾病的关系

硒蛋白M(SelM)是2002年应用生物信息学方法发现的一种内质网硒蛋白,其二级结构中含有一个氧化还原调节基序CXXU,且该蛋白在脑中大量表达。SelM因具有维持机体氧化还原水平、保护神经细胞和调节钙稳态平衡等重要作用,近年成为研究热点。本文结合本课题组的研究结果,对硒蛋白M的最新研究进展、生物功能、与重大疾病的关系及今后研究方向等方面进行了综述和展望。     

简易旋转倒立摆及控制装置的系统设计简

采用ATmega128作为本旋转倒立摆控制装置的主控芯片,通过直流电机对旋转臂进行控制,实现对摆杆的旋转控制。用编码器对摆杆旋转角度进行测量,将旋转位移转换成数字脉冲实现控制。通过对编码器设定零点,运用PID算法实现精确控制摆杆的摆动角度与状态。测试结果表明,该简易旋转倒立摆及控制装置的系统设计方法科学,具有性能稳定、抗干扰能力强、控制精确,可靠性高,节能环保等优点。     

氦-氧等离子体针灭活肺癌A549细胞

研究了介质阻挡放电等离子体针对肺癌A549细胞的灭活机制, 探讨从不锈钢管注入到氦等离子体尾流区域的氧气含量对杀灭肺癌细胞A549的影响. 利用中性红吸收测试法定性观察了等离子体处理后死亡的细胞和活着的细胞的形态区别, 并且定量测定了不同条件下的细胞存活率. 在固定功率24 W的处理过程中, 氦-氧等离子体的灭活效率主要取决于等离子体曝光时间以及氦气中添加氧气的百分含量. 实验结果显示最好的处理参数为: 处理时间150 s, 800 mL/min的氦气添加3%氧气, 保持针距样品的距离为3 mm. 根据氦-氧等离子体发射光谱, 可以推断在细胞灭活过程中, 氦-氧等离子体中的活性粒子(如羟基和氧自由基)起主要作用.     

大气条件等离子体针处理Enterococcus faecalis菌

自行研制的等离子体针在大气压下通过介质阻挡放电产生的等离子体,再由喷嘴处安装的漏斗形装置聚焦形成针状等离子体. 然后对针状等离子体的基本特性和杀Enterococcus faecalis(E. faecalis)菌进行了研究,E. faecalis菌是一种引起完善充填根管再感染的主要微生物. 当等离子体针功率为5-28W时,对等离子体的温度进行了测量,表明它不同于其他热杀菌方式. 通过改变等离子体针内电极末端注入的氧气量,发现适当的氧气量,不仅增加等离子体内含氧粒子的浓度而且对等离子体的长度影响也不明显. 实验表明最佳参数为功率15W,0.1m3·h-1氦和2.5%氧气,间距12mm,处理时间30 s. 为了找出杀菌的关键粒子,进一步比较了大气压下的等离子体针的发射光谱与agar(琼脂)2mm下的光谱并找出关键粒子.     

Removal of NO Molecules by a Novel Atmospheric Pressure Plasma Apparatus

A novel atmospheric pressure plasma apparatus （APPA） is designed with a liquid electrode, and its discharging characteristics are studied. Relatively uniform and intense discharge can be realized in the APPA system. An experimental study on removal of NO molecules is carried out by using the APPA, and more than 95.5% of NO is decomposed when the NO initial concentration is lower than 400ppm. Removal of NO efficiency increases rapidly with the increasing discharge power. Compared with the absence of O2, more NO2 is generated with the increase of O2 concentration. However, most of the NO molecules are decomposed to N2 and O2 directly, when O2 concentration changes from 0 to 1.1 vol%.     

Effect of the Pulse Duty Cycle on Characteristics of Plasma Electrolytic Oxidation Coatings Formed on AZ31 Magnesium Alloy

Ceramic coatings are synthesized on AZ31 magnesium alloy in alkaline silicate solution by the method of plasma electrolytic oxidation. The effect of two different duty cycles （10% and 50%） on the structure and corrosive properties of the coatings is investigated. It is found that the coatings are mainly composed of MgO, Mg2SiO4 and MgF2 through XRD analysis. SEM images indicate that coatings formed at 50% duty cycle have a relatively coarse surface with larger pore size and fewer pores, and have a slower growth rate than those formed at 10% duty cycle with the same treatment time. However, the results of potentiodynamic polarization tests demonstrate that coatings formed at 50% duty cycle exhibit better corrosion resistance as a result of more compact microstructure.     

Microstructure and Corrosion Performance of Oxide Coatings on Aluminium by Plasma Electrolytic Oxidation in Silicate and Phosphate Electrolytes

Ceramic coatings are fabricated on pure aluminium by plasma electrolytic oxidation （PEO） in three kinds of electrolyte systems [E1： 0.05M NaOH＋0.033M Na2SiO3, E2： 0.025M NaOH＋0.008M （NAPO3）6 and E3： 0.025M NaOH＋0.066M Na2SiO3＋0.008M （NAPO3）6]. The voltage-time responses show that the PEO process of E2 has the highest discharging voltage, which results in the biggest pores and heaviest cracks on the surfaces. X-ray diffraction results show that coatings produced in E1 and E3 are mainly composed of γ-Al2O3 and mullite, while coatings produced in E2 are mainly composed of a-Al2O3. After PEO treatment the corrosion resistance of aluminium is improved significantly and the coatings produced in E3 perform the best corrosion resistance.     

异翅独尾草（百合科）的胚胎学研究

异翅独尾草子房内部结构特殊，子房壁内外表层细胞特化，腔内具贮水组织；胚珠外面覆以特殊附属物－假种皮；珠心组织在珠孔端及合点端细胞具明显的极性分化，胚囊为７细胞８核的蓼型结构。