聚丙烯相对分子质量对以马来酸酐/苯乙烯为接枝单体的聚丙烯长链支化改性的影响

以马来酸酐/苯乙烯混合物为接枝单体,采用反应挤出制备长链支化聚丙烯,研究了不同相对分子质量聚丙烯在自由基反应中的活性,通过红外光谱表征改性聚丙烯的相对接枝率,表明大分子聚丙烯接枝率高于小分子。通过流变性质表征接枝物支化结构,并且通过对改性聚丙烯凝胶渗透色谱结果进行高斯分解,分析聚合物中不同相对分子质量组分,表征改性前后聚合物接枝与降解反应程度,综合分析不同相对分子质量聚丙烯在接枝反应中的表现。结果表明,分子量分布窄、相对分子质量大的聚丙烯在自由基反应中更占优势,但相对分子质量过大也会导致降解反应加剧。

A review on the pathogenesis theory of cancerous toxin from the viewpoint of system theory

In recent years,traditional Chinese medicine(TCM)has made great progress in the prevention and treatment of cancer.It has gradually revealed its characteristics and advantages in clinical practice,including alleviating clinical symptoms,prolonging survival time,decreasing the adverse effects of chemotherapy,and improving living quality.However,clinical TCM treatment of cancer lacks systematic theoretical guidance,because ancient TCM has not formed a recognized theoretical system of cognitive cancer,and there still are different opinions on the pathogenesis of cancer.Due to the complexity of cancer,the essence of cancer pathogenesis has not been described accurately by using common pathogenic factors,such as pathogenic wind,cold,dampness,summer heat,dryness,and fire.Ancient and modern TCM physicians have a similar understanding that the occurrence of cancer is related to toxin.In the 1990s,the thought of cancerous toxin was first proposed by Prof Zhou Zhongying,a TCMmaster based onmore than 60 years of clinical practice,who used“pandemic Qi(Li-Qi)is a specific pathogenic factor of epidemic disease”in Wenyi Lun(Treatise on Pestilence)for references.The pathogenesis theory of cancerous toxin was gradually established under the guidance of the thought of cancerous toxin.It holds that the cancerous toxin,a special pathogenic factor of cancer,is the key pathogenesis of the occurrence of malignant tumors.According to the pathogenesis theory of cancerous toxin,the basic pathogenesis of malignant tumors is the accumulation of pathogenic factors and cancerous toxin,and the deficiency of the vital Qi(Zheng-Qi).Therefore,the treatment principle involves eliminating pathogenic factors,resolving cancerous toxin,and supporting the vital Qi.The anticancer detoxification methods and the classification of Chinese medicinal herbs with anticancer detoxification effects were put forward.System theory has much in common with the concepts in the theory system of TCM,such as the universal relation theory,asking for a concrete analysis of concrete conditions,the humanism thought,and so on.This article aims to describe,review,and analyze the pathogenesis theory of cancerous toxin based on system theory for clinical practices.

探讨数字化修复工艺技术在全口义齿复制中的应用1例

目的:通过全口牙列缺失应用数字化复制义齿完成修复的病例,探讨利用数字化技术改进传统方法,制作全口复制义齿的流程及临床应用。方法:采用数字化技术,利用模型扫描仪对旧义齿进行扫描,获取旧义齿的外形数据,使用五轴数控切削设备制作出蜡质暂时复制义齿;在患者口内重新确定垂直距离、颌位关系以及丰满度等;上架完成全口义齿人工牙一对一替换;医师试排牙验证颌位关系,边缘整塑制取闭口式印模;技师灌制终模型,再次上架调,制作蜡型、装盒装胶、热处理,制作完成最终复制义齿;患者戴牙。修复治疗完成。对患者进行满意度调查。结果:复制义齿顺利就位,美观效果好,固位力及稳定性好,少量调即实现平衡。复查无压痛,义齿咀嚼功能良好。复制义齿满意度视觉模拟评分在总体满意度、易清洁性、发音能力、舒适、美观及嚼碎功能等6个方面均高于96分。结论:对于长期戴用旧义齿无不适、对义齿咬合及外形满意、适合进行复制的患者,利用数字化修复工艺技术获取旧义齿表面形态,最终制作完成复制义齿。数字化复制义齿技术更利于患者尽快适应新义齿,减少患者临床就诊次数、简化临床和技工室操作步骤、优化修复效果,提高患者满意度。