A hyperbranched epoxy(AHEP)resin with terminal allyl groups was synthesized.The number average molecular weight of the synthesized AHEP is 1260,the multi-dispersion coefficient is 1.88,and the branching degree is 0.9....A hyperbranched epoxy(AHEP)resin with terminal allyl groups was synthesized.The number average molecular weight of the synthesized AHEP is 1260,the multi-dispersion coefficient is 1.88,and the branching degree is 0.9.The hyperbranched epoxy resin and bismaleimide(BMI)monomer were heated to extend the chain and then blended and cured with methyl nadic anhydride.Studies have found that when the molar ratio of AHEP:BDM is 1:2,the mechanical properties and heat resistance of the resin casting body reach the best.Among them,the impact toughness was 15.05 kg/m^(2),the bending strength was 101 MPa,and the heat resistance temperature index was 229.23℃.We used AHEP to toughen bismaleimide resin in three ways simultaneously:hyperbranched structure,allyl copolymerized brackets chain and flexible side chain(epoxy group)addition.Experiments have proved that AHEP can improve the flexibility of the BMI chain and maintain its heat resistance,thereby forming a matrix with excellent mechanical properties and processing properties.展开更多
目的探讨年龄≥55岁N1b期甲状腺乳头状癌(papillary carcinoma of the thyroid,PTC)患者癌症特异性生存期(cancer-specific survival,CSS)的影响因素,并构建随机生存森林(random survival forest,RSF)模型和进行风险分层,评估不同治疗...目的探讨年龄≥55岁N1b期甲状腺乳头状癌(papillary carcinoma of the thyroid,PTC)患者癌症特异性生存期(cancer-specific survival,CSS)的影响因素,并构建随机生存森林(random survival forest,RSF)模型和进行风险分层,评估不同治疗策略的生存获益。方法收集2004—2019年美国国家癌症研究所的监测、流行病学和最终结果(Surveillance,Epidemiology,and End Results,SEER)数据库中符合条件的2867例PTC患者的临床资料,按7∶3比例分为训练组(n=2008)和验证组(n=859)。采用Cox比例回归风险模型和Kaplan-Meier(K-M)生存分析法识别CSS的潜在危险因素。采用Lasso回归筛选关键变量,构建Lasso-Cox和RSF预测模型,并通过一致性C指数(C-index)、时间依赖受试者工作特征(time-dependent receiver operating characteristic,tROC)曲线及Brier评分评估模型的效能,进行风险分层,分析不同治疗策略的生存获益。结果Cox比例风险回归模型分析显示,年龄较大、远处转移、肿瘤直径较大、腺外侵犯程度高、已婚、不放疗、甲状腺腺叶切除及化疗是CSS的独立危险因素(均P<0.05)。Lasso回归筛选出年龄、肿瘤直径、腺外侵犯和远处转移4个关键变量。Lasso-Cox模型和RSF模型的区分度及校准度均较高,在训练组中RSF模型整体表现优于Lasso-Cox模型,在验证组中两者差异不明显。Log-rank分析显示,高风险组的3年、5年、10年CSS率分别为68.15%、58.63%、37.52%,而低风险组分别为96.86%、94.38%、88.87%。手术方式及放疗对低风险组生存无显著影响,而在高风险组中显示出显著的生存差异。结论本研究构建的RSF模型对年龄≥55岁N1b期PTC患者的CSS具有较好的预测能力,有助于其风险分层,为临床治疗决策提供依据。展开更多
基金Funded by National Natural Science Foundation of China(No.51672201)。
文摘A hyperbranched epoxy(AHEP)resin with terminal allyl groups was synthesized.The number average molecular weight of the synthesized AHEP is 1260,the multi-dispersion coefficient is 1.88,and the branching degree is 0.9.The hyperbranched epoxy resin and bismaleimide(BMI)monomer were heated to extend the chain and then blended and cured with methyl nadic anhydride.Studies have found that when the molar ratio of AHEP:BDM is 1:2,the mechanical properties and heat resistance of the resin casting body reach the best.Among them,the impact toughness was 15.05 kg/m^(2),the bending strength was 101 MPa,and the heat resistance temperature index was 229.23℃.We used AHEP to toughen bismaleimide resin in three ways simultaneously:hyperbranched structure,allyl copolymerized brackets chain and flexible side chain(epoxy group)addition.Experiments have proved that AHEP can improve the flexibility of the BMI chain and maintain its heat resistance,thereby forming a matrix with excellent mechanical properties and processing properties.
文摘目的探讨年龄≥55岁N1b期甲状腺乳头状癌(papillary carcinoma of the thyroid,PTC)患者癌症特异性生存期(cancer-specific survival,CSS)的影响因素,并构建随机生存森林(random survival forest,RSF)模型和进行风险分层,评估不同治疗策略的生存获益。方法收集2004—2019年美国国家癌症研究所的监测、流行病学和最终结果(Surveillance,Epidemiology,and End Results,SEER)数据库中符合条件的2867例PTC患者的临床资料,按7∶3比例分为训练组(n=2008)和验证组(n=859)。采用Cox比例回归风险模型和Kaplan-Meier(K-M)生存分析法识别CSS的潜在危险因素。采用Lasso回归筛选关键变量,构建Lasso-Cox和RSF预测模型,并通过一致性C指数(C-index)、时间依赖受试者工作特征(time-dependent receiver operating characteristic,tROC)曲线及Brier评分评估模型的效能,进行风险分层,分析不同治疗策略的生存获益。结果Cox比例风险回归模型分析显示,年龄较大、远处转移、肿瘤直径较大、腺外侵犯程度高、已婚、不放疗、甲状腺腺叶切除及化疗是CSS的独立危险因素(均P<0.05)。Lasso回归筛选出年龄、肿瘤直径、腺外侵犯和远处转移4个关键变量。Lasso-Cox模型和RSF模型的区分度及校准度均较高,在训练组中RSF模型整体表现优于Lasso-Cox模型,在验证组中两者差异不明显。Log-rank分析显示,高风险组的3年、5年、10年CSS率分别为68.15%、58.63%、37.52%,而低风险组分别为96.86%、94.38%、88.87%。手术方式及放疗对低风险组生存无显著影响,而在高风险组中显示出显著的生存差异。结论本研究构建的RSF模型对年龄≥55岁N1b期PTC患者的CSS具有较好的预测能力,有助于其风险分层,为临床治疗决策提供依据。
