目的探究光谱CT联合磁共振弥散加权成像(DWI)参数对肝细胞癌经导管动脉栓塞(TACE)的疗效及预后转归的评估价值。方法前瞻性选取2022年6月至2024年2月拟于平煤神马集团总医院行TACE的128例肝细胞癌患者作为研究对象,治疗4周后根据疗效分...目的探究光谱CT联合磁共振弥散加权成像(DWI)参数对肝细胞癌经导管动脉栓塞(TACE)的疗效及预后转归的评估价值。方法前瞻性选取2022年6月至2024年2月拟于平煤神马集团总医院行TACE的128例肝细胞癌患者作为研究对象,治疗4周后根据疗效分为有效组(n=81)和无效组(n=47)。比较两组患者的基线资料、光谱CT、DWI定量参数,采用多因素Logistic回归分析法分析影响肝细胞癌TACE疗效的相关因素,采用Spearman相关性分析光谱CT、DWI定量参数与肝细胞癌TACE疗效的相关性,比较不同预后转归患者的光谱CT、DWI定量参数,采用受试者工作特征(ROC)曲线分析光谱CT、DWI定量参数对肝细胞癌TACE预后转归的预测价值。结果有效组和无效组患者的肿瘤分期、甲胎蛋白、门静脉癌栓、分化程度比较差异均有统计学意义(P<0.05);治疗4周后,动脉期标准化碘浓度(AP-NIC)(0.19±0.05 vs 0.28±0.07)、静脉期标准化碘浓度(PP-NIC)(0.39±0.11 vs 0.55±0.12)、能谱曲线斜率(λHU)(1.24±0.42 vs 1.87±0.34)比较,有效组明显低于无效组,表观扩散系数(ADC)[(1.62±0.45)×10^(-3)mm^(2)/s vs(1.25±0.32)×10^(-3)mm^(2)/s]比较有效组明显高于无效组,差异均有统计学意义(P<0.05);校正前多因素Logistic回归分析结果显示,肿瘤分期、甲胎蛋白、分化程度、门静脉癌栓,治疗4周后的AP-NIC、PP-NIC、λHU及ADC均是肝细胞癌TACE疗效的影响因素(P<0.05),校正后多因素Logistic回归分析结果显示,治疗4周后的AP-NIC、PP-NIC、λHU及ADC仍是肝细胞癌TACE疗效的影响因素(P<0.05);Spearman相关性分析结果显示,治疗4周后的AP-NIC、PP-NIC、λHU与肝细胞癌TACE疗效呈正相关(r=0.797、0.779、0.794,P<0.05),治疗4周后的ADC与肝细胞癌TACE疗效呈负相关(r=-0.770,P<0.05);治疗4周后的AP-NIC(0.20±0.06)vs(0.30±0.08)、PP-NIC(0.37±0.09)vs(0.50±0.13)、λHU(1.34±0.08)vs(1.78±0.14)比较,预后良好组明显低于预后不良组,ADC[(1.55±0.24)×10^(-3)mm^(2)/s vs(1.29±0.30)×10^(-3)mm^(2)/s]比较,预后良好组明显高于预后不良组,差异均有统计学意义(P<0.05);ROC分析结果显示,治疗4周后AP-NIC、PP-NIC、λHU及ADC联合预测肝细胞癌TACE预后转归曲线下面积(AUC)为0.932,敏感度、特异度分别为91.43%、84.09%,明显大于各定量参数单独预测(P<0.05)。结论AP-NIC、PP-NIC、λHU及ADC参数与肝细胞癌TACE疗效、预后转归密切相关,AP-NIC、PP-NIC、λHU及ADC联合预测肝细胞癌TACE预后转归具有良好的参考价值。展开更多
Large biases exist in real-time ENSO prediction, which can be attributed to uncertainties in initial conditions and model parameters. Previously, a 4D variational （4D-Vat） data assimilation system was developed for ...Large biases exist in real-time ENSO prediction, which can be attributed to uncertainties in initial conditions and model parameters. Previously, a 4D variational （4D-Vat） data assimilation system was developed for an intermediate coupled model （ICM） and used to improve ENSO modeling through optimized initial conditions. In this paper, this system is further applied to optimize model parameters. In the ICM used, one important process for ENSO is related to the anomalous temperature of subsurface water entrained into the mixed layer （Te）, which is empirically and explicitly related to sea level （SL） variation. The strength of the thermocline effect on SST （referred to simply as ＂the thermocline effect＂） is represented by an introduced parameter, （l＇Te. A numerical procedure is developed to optimize this model parameter through the 4D-Var assimilation of SST data in a twin experiment context with an idealized setting. Experiments having their initial condition optimized only, and having their initial condition plus this additional model parameter optimized, are compared. It is shown that ENSO evolution can be more effectively recovered by including the additional optimization of this parameter in ENSO modeling. The demonstrated feasibility of optimizing model parameters and initial conditions together through the 4D-Var method provides a modeling platform for ENSO studies. Further applications of the 4D-Vat data assimilation system implemented in the ICM are also discussed.展开更多
Using the method of undetermined function, a set of 12 parameter rectangular plate element with double set parameter and geometry symmetry is constructed. Their consistency error are O(h\+2) , one order higher than...Using the method of undetermined function, a set of 12 parameter rectangular plate element with double set parameter and geometry symmetry is constructed. Their consistency error are O(h\+2) , one order higher than the usual 12 parameter rectangular plate elements.展开更多
PLS （Partial Least Squares regression） is introduced into an automatic estimation of fundamental stellar spectral parameters. It extracts the most correlative spectral component to the parameters （Teff, log g and [...PLS （Partial Least Squares regression） is introduced into an automatic estimation of fundamental stellar spectral parameters. It extracts the most correlative spectral component to the parameters （Teff, log g and [Fe/H]）, and sets up a linear regression function from spectra to the corresponding parameters. Considering the properties of stellar spectra and the PLS algorithm, we present a piecewise PLS regression method for estimation of stellar parameters, which is composed of one PLS model for Teff, and seven PLS models for log g and [Fe/H] estimation. Its performance is investigated by large experiments on flux calibrated spectra and continuum normalized spectra at different signal-to-noise ratios （SNRs） and resolutions. The results show that the piecewise PLS method is robust for spectra at the medium resolution of 0.23 nm. For low resolution 0.5 nm and 1 nm spectra, it achieves competitive results at higher SNR. Experiments using ELODIE spectra of 0.23 nm resolution illustrate that our piecewise PLS models trained with MILES spectra are efficient for O ～ G stars： for flux calibrated spectra, the systematic offsets are 3.8%, 0.14 dex, and -0.09 dex for Teff, log g and [Fe/H], with error scatters of 5.2%, 0.44 dex and 0.38 dex, respectively; for continuum normalized spectra, the systematic offsets are 3.8%, 0.12dex, and -0.13 dex for Teff, log g and [Fe/H], with error scatters of 5.2%, 0.49 dex and 0.41 dex, respectively. The PLS method is rapid, easy to use and does not rely as strongly on the tightness of a parameter grid of templates to reach high precision as Artificial Neural Networks or minimum distance methods do.展开更多
文摘目的探究光谱CT联合磁共振弥散加权成像(DWI)参数对肝细胞癌经导管动脉栓塞(TACE)的疗效及预后转归的评估价值。方法前瞻性选取2022年6月至2024年2月拟于平煤神马集团总医院行TACE的128例肝细胞癌患者作为研究对象,治疗4周后根据疗效分为有效组(n=81)和无效组(n=47)。比较两组患者的基线资料、光谱CT、DWI定量参数,采用多因素Logistic回归分析法分析影响肝细胞癌TACE疗效的相关因素,采用Spearman相关性分析光谱CT、DWI定量参数与肝细胞癌TACE疗效的相关性,比较不同预后转归患者的光谱CT、DWI定量参数,采用受试者工作特征(ROC)曲线分析光谱CT、DWI定量参数对肝细胞癌TACE预后转归的预测价值。结果有效组和无效组患者的肿瘤分期、甲胎蛋白、门静脉癌栓、分化程度比较差异均有统计学意义(P<0.05);治疗4周后,动脉期标准化碘浓度(AP-NIC)(0.19±0.05 vs 0.28±0.07)、静脉期标准化碘浓度(PP-NIC)(0.39±0.11 vs 0.55±0.12)、能谱曲线斜率(λHU)(1.24±0.42 vs 1.87±0.34)比较,有效组明显低于无效组,表观扩散系数(ADC)[(1.62±0.45)×10^(-3)mm^(2)/s vs(1.25±0.32)×10^(-3)mm^(2)/s]比较有效组明显高于无效组,差异均有统计学意义(P<0.05);校正前多因素Logistic回归分析结果显示,肿瘤分期、甲胎蛋白、分化程度、门静脉癌栓,治疗4周后的AP-NIC、PP-NIC、λHU及ADC均是肝细胞癌TACE疗效的影响因素(P<0.05),校正后多因素Logistic回归分析结果显示,治疗4周后的AP-NIC、PP-NIC、λHU及ADC仍是肝细胞癌TACE疗效的影响因素(P<0.05);Spearman相关性分析结果显示,治疗4周后的AP-NIC、PP-NIC、λHU与肝细胞癌TACE疗效呈正相关(r=0.797、0.779、0.794,P<0.05),治疗4周后的ADC与肝细胞癌TACE疗效呈负相关(r=-0.770,P<0.05);治疗4周后的AP-NIC(0.20±0.06)vs(0.30±0.08)、PP-NIC(0.37±0.09)vs(0.50±0.13)、λHU(1.34±0.08)vs(1.78±0.14)比较,预后良好组明显低于预后不良组,ADC[(1.55±0.24)×10^(-3)mm^(2)/s vs(1.29±0.30)×10^(-3)mm^(2)/s]比较,预后良好组明显高于预后不良组,差异均有统计学意义(P<0.05);ROC分析结果显示,治疗4周后AP-NIC、PP-NIC、λHU及ADC联合预测肝细胞癌TACE预后转归曲线下面积(AUC)为0.932,敏感度、特异度分别为91.43%、84.09%,明显大于各定量参数单独预测(P<0.05)。结论AP-NIC、PP-NIC、λHU及ADC参数与肝细胞癌TACE疗效、预后转归密切相关,AP-NIC、PP-NIC、λHU及ADC联合预测肝细胞癌TACE预后转归具有良好的参考价值。
基金supported by the National Natural Science Foundation of China (Grant Nos. 41705082, 41475101, 41690122(41690120))a Chinese Academy of Sciences Strategic Priority Project-the Western Pacific Ocean System (Grant Nos. XDA11010105 and XDA11020306)+1 种基金the National Programme on Global Change and Air–Sea Interaction (Grant Nos. GASI-IPOVAI06 and GASI-IPOVAI-01-01)the China Postdoctoral Science Foundation, and a Qingdao Postdoctoral Application Research Project
文摘Large biases exist in real-time ENSO prediction, which can be attributed to uncertainties in initial conditions and model parameters. Previously, a 4D variational （4D-Vat） data assimilation system was developed for an intermediate coupled model （ICM） and used to improve ENSO modeling through optimized initial conditions. In this paper, this system is further applied to optimize model parameters. In the ICM used, one important process for ENSO is related to the anomalous temperature of subsurface water entrained into the mixed layer （Te）, which is empirically and explicitly related to sea level （SL） variation. The strength of the thermocline effect on SST （referred to simply as ＂the thermocline effect＂） is represented by an introduced parameter, （l＇Te. A numerical procedure is developed to optimize this model parameter through the 4D-Var assimilation of SST data in a twin experiment context with an idealized setting. Experiments having their initial condition optimized only, and having their initial condition plus this additional model parameter optimized, are compared. It is shown that ENSO evolution can be more effectively recovered by including the additional optimization of this parameter in ENSO modeling. The demonstrated feasibility of optimizing model parameters and initial conditions together through the 4D-Var method provides a modeling platform for ENSO studies. Further applications of the 4D-Vat data assimilation system implemented in the ICM are also discussed.
文摘Using the method of undetermined function, a set of 12 parameter rectangular plate element with double set parameter and geometry symmetry is constructed. Their consistency error are O(h\+2) , one order higher than the usual 12 parameter rectangular plate elements.
基金Supported by the National Natural Science Foundation of China
文摘PLS （Partial Least Squares regression） is introduced into an automatic estimation of fundamental stellar spectral parameters. It extracts the most correlative spectral component to the parameters （Teff, log g and [Fe/H]）, and sets up a linear regression function from spectra to the corresponding parameters. Considering the properties of stellar spectra and the PLS algorithm, we present a piecewise PLS regression method for estimation of stellar parameters, which is composed of one PLS model for Teff, and seven PLS models for log g and [Fe/H] estimation. Its performance is investigated by large experiments on flux calibrated spectra and continuum normalized spectra at different signal-to-noise ratios （SNRs） and resolutions. The results show that the piecewise PLS method is robust for spectra at the medium resolution of 0.23 nm. For low resolution 0.5 nm and 1 nm spectra, it achieves competitive results at higher SNR. Experiments using ELODIE spectra of 0.23 nm resolution illustrate that our piecewise PLS models trained with MILES spectra are efficient for O ～ G stars： for flux calibrated spectra, the systematic offsets are 3.8%, 0.14 dex, and -0.09 dex for Teff, log g and [Fe/H], with error scatters of 5.2%, 0.44 dex and 0.38 dex, respectively; for continuum normalized spectra, the systematic offsets are 3.8%, 0.12dex, and -0.13 dex for Teff, log g and [Fe/H], with error scatters of 5.2%, 0.49 dex and 0.41 dex, respectively. The PLS method is rapid, easy to use and does not rely as strongly on the tightness of a parameter grid of templates to reach high precision as Artificial Neural Networks or minimum distance methods do.
