PP/PLA盆底复合补片的制备与性能

以医用聚乳酸(PLA)切片为原料,采用静电纺丝技术制备PLA纤维膜,然后将其作为隔离层直接喷到两种不同的聚丙烯(PP)经编网眼结构网片上,制备PP/PLA盆底复合补片.对PP/PLA复合补片的表观形态、纤维直径、孔径、亲水性、断裂强力,以及PLA纤维膜与PP补片间的剥离强度进行试验研究.试验结果表明:复合补片中PLA纤维的直径较均匀,PP网片的结构对静电纺纤维膜的形态有很大影响,纤维膜趋于模仿接收网片的形态结构;两种结构的PP/PLA复合补片的水接触角均大于90°,即亲水性较差;PP补片和PLA纤维膜之间的剥离强度主要依靠物理吸附作用;PLA纤维膜的断裂强度较大、而断裂伸长率较小.     

牦牛舍饲密度及营养水平对其生长环境和血液生化指标的影响

在牦牛养殖实践中,无论暖季的放牧半舍饲饲养还是冷季的舍饲饲养,牛舍有害气体对牦牛健康和生长的影响日益受到关注。本研究选取体重相近、体况相似的健康公牦牛,设置高营养高密度组和低营养低密度组,观测不同处理氨气排放水平和牦牛采食、体重变化及血液指标。结果表明:(1)高营养高密度组日增重和采食量高于低营养低密度组。(2)高营养高密度组氨气浓度(1. 09 mg/m~3)显著(P0. 05)高于低营养低密度组(0. 53 mg/m~3)。(3)酶活性指标中,除低营养低密度组的谷丙转氨酶含量与试验前相比降低外,其余的酶活性指标均上升。(4)蛋白指标中,低营养低密度组中球蛋白含量高于试验前的含量,总蛋白、白蛋白含量均低于试验前的含量,高营养高密度组的总蛋白升高显著(P0. 05)。(5)能量指标中,低营养低密度组和高营养高密度组的总胆固醇含量和葡萄糖含量在试验后均有所提高,但甘油三酯的含量降低。由此可见,高营养高密度的饲养条件导致较高的牛舍氨气浓度,在主要血液生理生化指标上表现为牦牛的肝脏等功能受到一定影响。因此,今后要特别注意牛舍有害气体对牦牛健康的影响。     

Effects of Porosity on Structure and Performance of PP Meshes for Reparing Pelvic Floor Defects

Currently, polypropylene （PP） synthetic mesh is a kind of common material used for pelvic floor＇s repairing and reconstruction. The repairing mesh is generally made with different hole shape and size. Porosity is one of the most important indicators of PP mesh. Two different-structure PP meshes are selected through adopting corresponding target density in the heat setting process for meshes owning different porosity. Then performance and structure of two kinds meshes with different porosity are tested. The results showed that： the increase of porosity leaded to the decreases of meshes＇ thickness, tensile strength and bursting strength. Meshes＇ bending stiffness was reduced and they became softer, but there was no significant change in suture pulling-out force, which maybe associated with the large aperture of PP meshes.     

Processing and Mechanical Characterization of Electro-spun Polycaprolactone Membrane Coated Hernia Mesh

Composite hernia meshes designed in this paper consist of polypropylene( PP) knitted meshes and polycaprolactone( PCL)nanofiber membranes,which are produced by electro-spinning the solution composed of PCL as a solute and the mixture of dimethylformamide( DMF) and dichloromethane( DCM) as a solvent. The morphology and diameter of nanofibers in the membrane are well performed when the 15% PCL solution is electrospun under the condition of 18 k V,15 cm,0. 7 m L/h. The poresize of the membranes is less than 10 μm, where such kinds of arrangement are extremely compact to prevent the cells from growing in. The mechanical properties of the membrane with better arrangement state can reach 68. 8 c N/mm~2. The cytotoxicity test of the composite mesh demonstrates the nontoxicity of the materials.However,the bonding fastness between the membrane and the PP mesh is extremely unsubstantial. The better ways to bond PP mesh with PCL membranes should be discussed in the future.     

聚乳酸经编盆底修补网片的制备与热定型工艺

聚乳酸(PLA)生物相容性较好,在人体内可降解且产物的安全性较高。采用直径为0.138mm的国产PLA单丝,选用编链衬纬的经编网孔组织结构,在机号为E20的经编小样机上进行编织,制备得到可降解的PLA盆底修补网片。探讨了热定型工艺中的时间、温度对PLA网片的结构参数和力学性能的影响。结果表明,随着热定型温度的升高,网片的断裂强力增加,顶破强力降低,抗弯刚度增加,缝线拉脱力降低。网片在过高温度定型后性能改变明显,即网片变得更加脆硬并且易受冲击影响而发生断裂。网片在120和130℃下热定型后力学性能相近,但是高温更有利于稳定网片的尺寸和形状。热定型时间对网片的性能的影响基本无固定规律可寻,但是时间过长易导致网片的纵向弯曲刚度增加。因此基于稳定的强力和较低的弯曲刚度,PLA网片的热定型工艺选择温度为130℃,热定型时间为10min。以此工艺定型后的网片生物相容性显示:PLA网片厚重的结构和刚硬的性能特点导致网片暴露(发生率为13.33%),但是也使网片具有较低的收缩率(2.15±0.26)%。     

会操作的小老鼠

饿了,你一定知遵打开冰箱、微波炉去找食物,可你知道吗,小老鼠也一样能按按钮找吃的呢!