Dedicated to the memory of Professor Briton Chance on the ccasion of his 100th birthday(July24 th,2013),and remembering mary erciting discussions on the orygenation of breast cancer,ontumor hyporia in general and imag...Dedicated to the memory of Professor Briton Chance on the ccasion of his 100th birthday(July24 th,2013),and remembering mary erciting discussions on the orygenation of breast cancer,ontumor hyporia in general and imaging of the orygenation status of malignant tumors.Hypoxic tissue subvolumes are a hallmark feat ure of solid malignant tumors,relevant for cancertherapy and patient outcome because they increase both the intrinsic aggressiveness of tumor cells and their resist ance to several commonly used anticancer strategies.Pathogenetic mech-anisms leading to hypoxia are diverse,may coexist within the same tumor and are commonlygrouped according to the duration of their ffects.Chronic hypoxia is mainly caused by difusionlimitations resulting from enlarged intercapilary distances and adverse difusion geometriesand--to a lsser extent--by hypoxemia,compromised perfusion or long-lasting microregionalfow stops.Conversely,acute hypoxia preferentilly results from transient disruptions in per.fusion.While each of these features of the tumor microenvironment can contribute to a criticalreduction of oxy gen availability,the delivery of imaging agents(as well as nutrients and anti-cancer agents)may be compromised or remain unaffected,Thus,a critial appraisal of the ffectsof the various mechanisms leading to hypoxia with regard to the blood-bome delivery of imagingagents is necessary to judge their ability to correctly represent the hypoxic phenotype of solidmalignancies.展开更多
以无添加的低密度聚乙烯作为载体树脂,加入无胺爽滑剂、开口剂和抗氧化剂制成爽滑母料,然后添加一定比例的爽滑母料吹塑成 PE 热封膜,并对其进行无溶剂复合,研究了 PE 膜在复合及熟化后摩擦系数的变化。结果表明,在无溶剂复合过程中 PE...以无添加的低密度聚乙烯作为载体树脂,加入无胺爽滑剂、开口剂和抗氧化剂制成爽滑母料,然后添加一定比例的爽滑母料吹塑成 PE 热封膜,并对其进行无溶剂复合,研究了 PE 膜在复合及熟化后摩擦系数的变化。结果表明,在无溶剂复合过程中 PE 热封膜的摩擦系数始终保持在 0. 15 ~ 0. 25,并且在 40 ℃以内的熟化温度下,摩擦系数几乎保持不变,同时复合膜的热封强度保持在 63 N/15 mm 以上,剥离强度保持在 2. 2 N/15 mm 以上,60 μm PE 热封膜的透光率和雾度分别为 90. 8 和 0. 23,与相同厚度的普通 PE 膜的差距较小,完全符合 GB/T 10004—2008 中薄膜性能的要求,解决了采用胺类爽滑剂母料导致无溶剂复合产品摩擦系数变大的现象。展开更多
文摘Dedicated to the memory of Professor Briton Chance on the ccasion of his 100th birthday(July24 th,2013),and remembering mary erciting discussions on the orygenation of breast cancer,ontumor hyporia in general and imaging of the orygenation status of malignant tumors.Hypoxic tissue subvolumes are a hallmark feat ure of solid malignant tumors,relevant for cancertherapy and patient outcome because they increase both the intrinsic aggressiveness of tumor cells and their resist ance to several commonly used anticancer strategies.Pathogenetic mech-anisms leading to hypoxia are diverse,may coexist within the same tumor and are commonlygrouped according to the duration of their ffects.Chronic hypoxia is mainly caused by difusionlimitations resulting from enlarged intercapilary distances and adverse difusion geometriesand--to a lsser extent--by hypoxemia,compromised perfusion or long-lasting microregionalfow stops.Conversely,acute hypoxia preferentilly results from transient disruptions in per.fusion.While each of these features of the tumor microenvironment can contribute to a criticalreduction of oxy gen availability,the delivery of imaging agents(as well as nutrients and anti-cancer agents)may be compromised or remain unaffected,Thus,a critial appraisal of the ffectsof the various mechanisms leading to hypoxia with regard to the blood-bome delivery of imagingagents is necessary to judge their ability to correctly represent the hypoxic phenotype of solidmalignancies.
