This paper investigates the finite time blow-up of nonnegative solutions for a nonlinear diffusion system with a more complicated source term, which is a product of localized source, local source, and weight function,...This paper investigates the finite time blow-up of nonnegative solutions for a nonlinear diffusion system with a more complicated source term, which is a product of localized source, local source, and weight function, and complemented by homogeneous Dirichlet boundary conditions. The criteria are proposed to identify simultaneous and nonsimultaneous blow-up solutions. Moreover, the related classification for the four parameters in the model is optimal and complete. The results extend those in Zhang and Yang [12].展开更多
目的通过对同一组鼻咽癌病例两种不同感兴趣区(Region Of Interest,ROI)勾画方法:在原发灶最大层面沿病灶边缘手工绘制不规则形ROI整体测量法(Whole Measurement Method,W法)与大小为30mm2左右的圆形ROI置于病灶中心局部测量法(Regional...目的通过对同一组鼻咽癌病例两种不同感兴趣区(Region Of Interest,ROI)勾画方法:在原发灶最大层面沿病灶边缘手工绘制不规则形ROI整体测量法(Whole Measurement Method,W法)与大小为30mm2左右的圆形ROI置于病灶中心局部测量法(Regional Mesurement Method,R法)测量表观扩散系数值(apparent diffusion coefficient,ADC)的比较,寻求可重复性及稳定性较好的鼻咽癌ADC值测量方法。方法连续对100例经病理证实鼻咽癌初诊患者行MRI常规扫描和扩散加权成像(DW-MRI)扫描(b值取800s/mm2)。两名医师各自独立采用W法和R法测量鼻咽癌原发灶的ADC值。两种测量方法的ADC值比较采用配对设计t检验;相关性比较采用pearson相关分析;两位医师测量结果的重复性分析采用BlandAltman法。以P<0.05为差异有统计学意义。两种测量方法的稳定性比较用变异系数(coefficient of variations,CV)分析:由5位医生、在5个不同时间点分别用两种方法测量同一病人鼻咽病灶的ADC值,并计算出CV。结果医师1用W法和R法测得的鼻咽癌ADC值分别为(0.79±0.14)×10-3mm2/s和(0.76±0.15)×10-3mm2/s;医师2用W法和R法测得的鼻咽癌ADC值分别为(0.82±0.18)×10-3mm2/s和(0.78±0.20)×10-3mm2/s。两名观测者采用R法所测得ADC值均低于W法(医师1:t=-5.739,P<0.001;医师2:t=-5.221,P<0.001)。采用R法与W法两种测量方法的r值分别为0.675、0.763,W法略好于R法。Bland-Altman法分析两种测量方法的一致性结果为:用W法测量ADC值落在一致性界限外的数据点数为5个,占5%;用R法测量ADC值落在一致性界限外的数据点数为6个,占6%;W法略优于R法。5位医生、在5个不同时间点分别用两种方法测量同一鼻咽病灶的ADC值的比较:W法的CV为2%,R法为8%,用W法测量ADC值的稳定性优于R法。结论最大层面手工勾边整体测量法与圆形小ROI局部测量法所测得鼻咽癌原发病灶ADC值在不同观测者间的一致性均较好,但手工勾边整体测量法的可重复性、稳定性略优于圆形小ROI局部测量法。展开更多
基金Supported by the National Natural Science Foundation of China(11071100),supported by National Natural Science Foundation of ChinaNatural Science Foundation of Guangxi(2011jjA10044),Natural Science Foundation of Guangxi
文摘This paper investigates the finite time blow-up of nonnegative solutions for a nonlinear diffusion system with a more complicated source term, which is a product of localized source, local source, and weight function, and complemented by homogeneous Dirichlet boundary conditions. The criteria are proposed to identify simultaneous and nonsimultaneous blow-up solutions. Moreover, the related classification for the four parameters in the model is optimal and complete. The results extend those in Zhang and Yang [12].
