Pyrolysis of cyclohexane was conducted with a plug flow tube reactor in the temperature range of 873-973 K. Based on the experimental data, the mechanism and kinetic model of cyclohexane pyrolysis reaction were propos...Pyrolysis of cyclohexane was conducted with a plug flow tube reactor in the temperature range of 873-973 K. Based on the experimental data, the mechanism and kinetic model of cyclohexane pyrolysis reaction were proposed. The kinetic analysis shows that overall conversion of cyclohexane is a first order reaction, of which the rate constant increased from 0.0086 to 0.0225 to 0.0623 s-1 with the increase of temperature from 873 to 923 to 973 K, and the apparent activation energy was determined to be 155.0±1.0 kJ mol-1. The mechanism suggests that the cyclohexane is consumed by four processes：the homolysis of C-C bond （Path I）, the homolysis of C-H bond （Path II） in reaction chain initia- tion, the H-abstraction of various radicals from the feed molecules in reaction chain propagation （Path III）, and the process associated with coke formation （Path IV）. The reaction path probability （RPP） ratio of XPath I：XPath II ： XPath III ： XPath IV was 0.5420：0.0045：0.3897：0.0638 at 873 K, and 0.4336 ： 0.0061 ： 0.4885 ： 0.0718 at 973 K, respectively.展开更多
Heteroarm star-shaped polymers were synthesized by conventional free radical polymerization in two steps by the use of polyfunctional chain transfer agent.In the first step,free radical polymerization of methyl methac...Heteroarm star-shaped polymers were synthesized by conventional free radical polymerization in two steps by the use of polyfunctional chain transfer agent.In the first step,free radical polymerization of methyl methacrylate was carried out in the presence of a polyfunctional chain transfer agent,pentaerythritol tetrakis(3-mercaptopropinate).At appropriate monomer conversions,two-arm PMMA having two residual thiol groups at the chain center or three-arm PMMA having one residual thiol group at the core were o...展开更多
目的:血清游离轻链(free light chain,FLC)在多种疾病中表达异常,但其在肺癌中的表达尚不清楚,本研究旨在探讨血清FLC在肺癌中的表达及诊断价值。方法:选取2021年1至12月湖南师范大学附属湘东医院收治的80例肺癌患者作为肺癌组,另选取...目的:血清游离轻链(free light chain,FLC)在多种疾病中表达异常,但其在肺癌中的表达尚不清楚,本研究旨在探讨血清FLC在肺癌中的表达及诊断价值。方法:选取2021年1至12月湖南师范大学附属湘东医院收治的80例肺癌患者作为肺癌组,另选取同时期的80例健康体检人员作为对照组。收集所有参与者的一般资料、血清κFLC和λFLC水平;收集肺癌组患者住院期间的相关临床指标[血清癌胚抗原(carcinoembryonic antigen,CEA)、细胞角蛋白-19片段抗原(cytokeratin fragment antigen 21-1,CYFRA21-1)水平,以及肿瘤直径、组织学分型、TNM分期、是否有淋巴结转移]。比较肺癌组和对照组血清FLC[κFLC、λFLC、FLC(κ+λ)]的表达水平。将80例肺癌患者按性别、年龄、吸烟史、肿瘤直径、TNM分期、组织学分型、淋巴结转移进行分组,比较组间血清κFLC、λFLC表达水平的差异。采用受试者操作特征(receiver operating characteristic,ROC)曲线评价血清FLC水平单独及联合其他指标在肺癌中的诊断价值。结果:肺癌组血清FLC(κ+λ)、κFLC表达水平均显著高于对照组,差异均有统计学意义(均P<0.001);而2组间血清λFLC表达水平的差异无统计学意义(P>0.05)。不同肿瘤直径、组织学分型、TNM分期的肺癌血清κFLC表达水平差异均无统计学意义(均P>0.05);但是,有淋巴结转移的肺癌患者血清κFLC水平高于无淋巴结转移的肺癌患者,且差异有统计学意义(P=0.033)。不同肿瘤直径、组织学分型肺癌患者的血清λFLC表达水平差异均无统计学意义(均P>0.05);但是,TNM分期III期+IV期、有淋巴结转移的肺癌患者血清λFLC表达水平分别高于TNM分期I期+II期、无淋巴结转移的肺癌患者,差异均有统计学意义(分别P=0.033,P=0.019)。κFLC、CEA诊断肺癌的曲线下面积(area under the curve,AUC)差异无统计学意义(P=0.333)。在2项联合诊断肺癌的指标中,κFLC+CYFRA21-1的诊断效能(AUC=0.875)及敏感性(71.3%)最高。κFLC+λFLC+CEA+CYFRA21-1联合诊断肺癌的AUC为0.915(95%CI 0.860~0.953,P<0.001)。结论:血清FLC在肺癌中高表达,并且与肺癌的浸润和转移有关。血清FLC尤其是κFLC对肺癌的诊断具有价值,FLC、CEA、CYFRA21-1联合检测的诊断效能最佳。展开更多
基金supported by the Natural Science Foundation of Zhejiang Province(Y4110276)for financial support
文摘Pyrolysis of cyclohexane was conducted with a plug flow tube reactor in the temperature range of 873-973 K. Based on the experimental data, the mechanism and kinetic model of cyclohexane pyrolysis reaction were proposed. The kinetic analysis shows that overall conversion of cyclohexane is a first order reaction, of which the rate constant increased from 0.0086 to 0.0225 to 0.0623 s-1 with the increase of temperature from 873 to 923 to 973 K, and the apparent activation energy was determined to be 155.0±1.0 kJ mol-1. The mechanism suggests that the cyclohexane is consumed by four processes：the homolysis of C-C bond （Path I）, the homolysis of C-H bond （Path II） in reaction chain initia- tion, the H-abstraction of various radicals from the feed molecules in reaction chain propagation （Path III）, and the process associated with coke formation （Path IV）. The reaction path probability （RPP） ratio of XPath I：XPath II ： XPath III ： XPath IV was 0.5420：0.0045：0.3897：0.0638 at 873 K, and 0.4336 ： 0.0061 ： 0.4885 ： 0.0718 at 973 K, respectively.
文摘Heteroarm star-shaped polymers were synthesized by conventional free radical polymerization in two steps by the use of polyfunctional chain transfer agent.In the first step,free radical polymerization of methyl methacrylate was carried out in the presence of a polyfunctional chain transfer agent,pentaerythritol tetrakis(3-mercaptopropinate).At appropriate monomer conversions,two-arm PMMA having two residual thiol groups at the chain center or three-arm PMMA having one residual thiol group at the core were o...
文摘目的:血清游离轻链(free light chain,FLC)在多种疾病中表达异常,但其在肺癌中的表达尚不清楚,本研究旨在探讨血清FLC在肺癌中的表达及诊断价值。方法:选取2021年1至12月湖南师范大学附属湘东医院收治的80例肺癌患者作为肺癌组,另选取同时期的80例健康体检人员作为对照组。收集所有参与者的一般资料、血清κFLC和λFLC水平;收集肺癌组患者住院期间的相关临床指标[血清癌胚抗原(carcinoembryonic antigen,CEA)、细胞角蛋白-19片段抗原(cytokeratin fragment antigen 21-1,CYFRA21-1)水平,以及肿瘤直径、组织学分型、TNM分期、是否有淋巴结转移]。比较肺癌组和对照组血清FLC[κFLC、λFLC、FLC(κ+λ)]的表达水平。将80例肺癌患者按性别、年龄、吸烟史、肿瘤直径、TNM分期、组织学分型、淋巴结转移进行分组,比较组间血清κFLC、λFLC表达水平的差异。采用受试者操作特征(receiver operating characteristic,ROC)曲线评价血清FLC水平单独及联合其他指标在肺癌中的诊断价值。结果:肺癌组血清FLC(κ+λ)、κFLC表达水平均显著高于对照组,差异均有统计学意义(均P<0.001);而2组间血清λFLC表达水平的差异无统计学意义(P>0.05)。不同肿瘤直径、组织学分型、TNM分期的肺癌血清κFLC表达水平差异均无统计学意义(均P>0.05);但是,有淋巴结转移的肺癌患者血清κFLC水平高于无淋巴结转移的肺癌患者,且差异有统计学意义(P=0.033)。不同肿瘤直径、组织学分型肺癌患者的血清λFLC表达水平差异均无统计学意义(均P>0.05);但是,TNM分期III期+IV期、有淋巴结转移的肺癌患者血清λFLC表达水平分别高于TNM分期I期+II期、无淋巴结转移的肺癌患者,差异均有统计学意义(分别P=0.033,P=0.019)。κFLC、CEA诊断肺癌的曲线下面积(area under the curve,AUC)差异无统计学意义(P=0.333)。在2项联合诊断肺癌的指标中,κFLC+CYFRA21-1的诊断效能(AUC=0.875)及敏感性(71.3%)最高。κFLC+λFLC+CEA+CYFRA21-1联合诊断肺癌的AUC为0.915(95%CI 0.860~0.953,P<0.001)。结论:血清FLC在肺癌中高表达,并且与肺癌的浸润和转移有关。血清FLC尤其是κFLC对肺癌的诊断具有价值,FLC、CEA、CYFRA21-1联合检测的诊断效能最佳。
