氧离子注入增强人工关节软骨材料-UHMWPE的耐磨性

用高能离子注入机对超高分子量聚乙烯 (U HMWPE)进行了 O+注入改性 ,注入能量为 4 5 0 ke V和 10 0ke V,剂量分别为 1× 10 1 5/cm2 ,5× 10 1 5/cm2和 1× 10 1 6 /cm2。以 Si3N4 球为上销样 ,UHMWPE为下盘样组成摩擦副 ,在销盘摩擦试验机上评价它们在干摩擦和蒸馏水润滑条件下的磨损性能。结果表明 ,几种注入工艺均增强了UHMWPE的耐磨性 ,但提高了其摩擦系数 ,其中以能量为 4 5 0 Ke V,剂量为 5× 10 1 5/cm2的注入样品耐磨性最好。未注入 U HMWPE的磨损主要表现为黏着、塑性变形和犁沟 ,注入 U HMWPE的磨损主要为表面硬化层疲劳裂纹的萌生、扩展、剥落及磨粒磨损     

人体体温下UHMWPE人工髋臼材料压缩性能的试验研究

模拟人体体温下对超高分子量聚乙烯（UHMWPE）人工髋臼材料进行了压缩力学性能的试验研究,并与室温下的试验结果进行了对比.当由室温22℃升高到体温37℃和40℃时,其屈服应力呈明显的下降趋势,分别下降了23.1%和31.9%,由体温37℃升高到40℃时,二者仅差3℃,其屈服应力亦下降了11.5%.同时还对不同加载速度下UHMWPE试件压缩变形过程进行了红外辐射温度的监测与分析.不同加载速度下试件压缩变形过程中的红外辐射温度均有明显升高,加载时间越长,试件平均红外辐射温度越高.试验结果分析表明,不能忽视植入人体后UHMWPE人工髋臼局部受压时温度的升高,特别不能忽视植入人体后在人体体温作用下其力学性能的改变和下降,人体体温的作用是UHMWPE人工髋臼出现过早失效的原因之一.本试验研究为UHMWPE材料在人体环境中的应用研究提供了参考.     

CGRP可以逆转由超高分子量聚乙烯引起鼠成骨细胞RANKL表达的实验研究

目的:探讨降钙素基因相关肽(CGRP)对超高分子聚乙烯(UHMWPE)引起的鼠成骨细胞RANKL代谢的影响。方法:将体外培养的鼠颅骨成骨细胞在UHMWPE微粒预处理后,加入外源性不同浓度的CGRP孵育48 h,提取各组细胞m RNA、蛋白,通过实时定量逆转录聚合酶链反应(RT-PCR)和western blot来观察成骨细胞OPG和RANKL m RNA、蛋白表达水平的变化。结果:微粒明显刺激了RANKL的表达,降低了OPG的表达;CGRP显著抑制了鼠成骨细胞RANKL的表达。结论:CGRP抑制微粒介导的骨质溶解作用是可能是通过下调RANKL的表达实现的。     

Tensile Behavior of High-Strength,Strain-Hardening Cement-Based Composites (HS-SHCC) Reinforced with Continuous Textile Made of Ultra-High-Molecular-Weight Polyethylene

The paper at hand presents an investigation of the tensile behavior of high-strength, strain-hardening cement-based composites (HS-SHCC), reinforced with a single layer of continuous, two-dimensional textile made of ultra-high molecular weight polyethylene (UHMWPE). Uniaxial tension tests were performed on the bare UHMWPE textiles, on plain HS-SHCC, and on the hybrid fiber-reinforced composites. The bond properties between the textile yarns and the surrounding composite were investigated in single-yarn pullout experiments. In order to assess the influence of bond strength between the yarn and HS-SHCC on the tensile behavior of the composites with hybrid fiber reinforcement, the textile samples were analyzed both with, and without, an additional coating of epoxy resin and sand. Compared to the composites reinforced with carbon yarns in previous studies by the authors, the high elongation capacity of the UHMWPE textile established the higher strain capacity of the hybrid fiber-reinforced composites, and showed superior energy absorption capacity up to failure. The UHMWPE textile limited the average crack width in comparison with that of plain HS-SHCC, but led to slightly larger crack widths when compared to equivalent composites reinforced with carbon textile, the reason for which was traced back to the lower Young’s modulus and the higher elongation capacity of the polymer textile.     

种植体应用于义颌修复上颌骨缺损的研究进展

义颌修复上颌骨缺损已有上百年历史,直至今日义颌修复依然被认为是评判上颌骨重建的金标准.1986年Branemark等首次将种植引入上颌骨缺损的义颌修复中.本文从种植体在义颌修复中的意义、放疗对颌骨内种植体的影响、植入时机和部位、成功率及修复效果等方面,综述种植体在上颌骨缺损的义颌修复中的应用.     

超高分子聚乙烯颗粒刺激单核细胞高表达CD147/EMMPRIN

目的探讨不同浓度磨损颗粒对单核细胞表达细胞外基质金属蛋白酶诱导剂（CD147/EMMPRIN）的影响。方法根据颗粒/细胞比值实验分为0、1、10、100、500、1000共6组,将不同浓度的超高分子聚乙烯（UHMWPE）颗粒与人单核细胞株THP-1共培养24h,台盼蓝染色检测THP-1细胞存活率,利用流式细胞术、Real-time PCR和Western blot检测THP-1细胞CD147/EMMPRIN的表达。结果加入UHMWPE颗粒前及共培养24h后THP-1细胞存活率均大于90%。流式细胞术、Real-timePCR和Westernblot结果均显示加入UHMWPE颗粒后,CD147/EMMPRIN表达较对照组（即颗粒/细胞比值为0）增加,当颗粒/细胞比值在1-100范围时,CD147/EMMPRIN表达与颗粒浓度正相关,颗粒/细胞比值大于或等于100时,CD147/EMMPRIN稳定保持在高表达水平,不随颗粒浓度升高而变化。结论 UHMWPE颗粒刺激单核细胞高表达CD147/EMMPRIN,并呈浓度依赖性。     

Novel SiO2‐Supported Chromium Oxide/Chromocene Dual Site Catalysts for Synthesis of Bimodal UHMWPE/HDPE in Reactor Alloys

Polyethylene (PE) with bimodal molecular weight distribution (MWD) has drawn attention from both academia and industry. Bimodal PE combines great processability with outstanding mechanical properties. The single‐reactor technology process through a dual site catalyst system is an optimal strategy considering the economic effect and the manufacturing technique. To satisfy the demand of the dual site catalyst system for producing bimodal PE, novel SiO₂‐supported chromium oxide/chromocene dual site catalysts for ethylene polymerization are successfully synthesized and systematically investigated. The novel catalysts are prepared by using the residual hydroxyl groups on the surface of SiO₂‐supported chromium oxide (CrO_x) Phillips catalyst to introduce chromocene. It is found that the novel dual site catalysts combine the advantages of chromocene catalyst (S‐9 catalyst) and Phillips CrO_x/SiO₂ catalyst. The activities of the dual site catalysts are doubled at least compared to the S‐9 catalyst due to the high activity of the CrO_x active center. The products of the dual site catalysts show significantly high molecular weight (MW) with bimodal MWD through ultrahigh molecular weight polyethylene/high‐density polyethylene in reactor alloys. The dual site catalysts show great hydrogen response according to the hydrogen experiment results, which lead to the easy control of MW.     

等离子接枝处理超高分子量聚乙烯纤维

利用等离子接枝法对超高分子量聚乙烯纤维进行表面处理，在纤维表面产生活性官能团，并用紫外分析、红外分析探讨了纤维表面官能团的产生及变化。通过测定纤维复合材料层间剪切强度验证结构与性能的关系。     

液态氧化法处理超高分子量聚乙烯纤维

用液态氧化法对超高分子量聚乙烯纤维进行了表面处理，研究了处理介质、处理时间对超高分子量聚乙烯／环氧复合材料层间剪切强度的影响，用扫描电子显微镜、ＸＰＳ表面元素分析、毛细浸润法测接触角等方法探讨了纤维表面性能处理前后的变化，以及纤维与树脂的界面结合情况。     

Increased oxidative protection by high active vitamin E content and partial radiation crosslinking of UHMWPE

Vitamin E stabilization successfully improved long‐term oxidation resistance of wear‐resistant ultra‐high‐molecular‐weight polyethylene (UHMWPE) used for joint implants. Stabilization can be achieved by blending an antioxidant into the UHMWPE resin powder before consolidation and irradiation. Balancing the wear resistance and vitamin E content in the blend is the current challenge with this approach, because vitamin E hinders crosslinking of UHMWPE during irradiation, which decreases wear resistance. The vitamin E concentration in the blend is generally limited to less than 0.3 wt%. Wear‐ and oxidation‐resistant UHMWPE has been obtained previously by consolidating blends of pre‐irradiated UHMWPE powders (XPE) into an unmodified polyethylene matrix (PE), where the improvement in wear rate depended on the radiation dose and fraction of XPE. We hypothesized that increasing the vitamin E content in the unirradiated matrix would not compromise wear and would further improve the oxidative stability of XPE/PE blends. Pin‐on‐disk wear testing showed that the XPE/PE blends containing 0.1–1.0 wt% vitamin E in the matrix had comparable wear rates. We used an aggressive accelerated aging test in the presence of the pro‐oxidant squalene and oxidation induction time (OIT) test and found that higher amounts of vitamin E resulted in stronger oxidation resistance for XPE/PE blends. The mechanical strength and toughness of the blends were not affected by changing the vitamin E content in the matrix. Stabilizing UHMWPE with higher vitamin E content may extend the service life of UHMWPE implants. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1860–1867, 2018.