Objective To establish a body composition analysis system based on chest CT,and to observe its value for evaluating content of chest muscle and adipose.Methods T7—T8 layer CT images of 108 pneumonia patients were col...Objective To establish a body composition analysis system based on chest CT,and to observe its value for evaluating content of chest muscle and adipose.Methods T7—T8 layer CT images of 108 pneumonia patients were collected(segmented dataset),and chest CT data of 984 patients were screened from the COVID 19-CT dataset(10 cases were randomly selected as whole test dataset,the remaining 974 cases were selected as layer selection dataset).T7—T8 layer was classified based on convolutional neural network(CNN)derived networks,including ResNet,ResNeXt,MobileNet,ShuffleNet,DenseNet,EfficientNet and ConvNeXt,then the accuracy,precision,recall and specificity were used to evaluate the performance of layer selection dataset.The skeletal muscle(SM),subcutaneous adipose tissue(SAT),intermuscular adipose tissue(IMAT)and visceral adipose tissue(VAT)were segmented using classical fully CNN(FCN)derived network,including FCN,SegNet,UNet,Attention UNet,UNET++,nnUNet,UNeXt and CMUNeXt,then Dice similarity coefficient(DSC),intersection over union(IoU)and 95 Hausdorff distance(HD)were used to evaluate the performance of segmented dataset.The automatic body composition analysis system was constructed based on optimal layer selection network and segmentation network,the mean absolute error(MAE),root mean squared error(RMSE)and standard deviation(SD)of MAE were used to evaluate the performance of automatic system for testing the whole test dataset.Results The accuracy,precision,recall and specificity of DenseNet network for automatically classifying T7—T8 layer from chest CT images was 95.06%,84.83%,92.27%and 95.78%,respectively,which were all higher than those of the other layer selection networks.In segmentation of SM,SAT,IMAT and overall,DSC and IoU of UNet++network were all higher,while 95HD of UNet++network were all lower than those of the other segmentation networks.Using DenseNet as the layer selection network and UNet++as the segmentation network,MAE of the automatic body composition analysis system for predicting SM,SAT,IMAT,VAT and MAE was 27.09,6.95,6.65 and 3.35 cm 2,respectively.Conclusion The body composition analysis system based on chest CT could be used to assess content of chest muscle and adipose.Among them,the UNet++network had better segmentation performance in adipose tissue than SM.展开更多
Significance of body material and temperature variation on burning time and burning rate of Si/Pb O/Pb_3O_4/FG and B/BaCrO_4/FG pyrotechnic delay compositions were experimentally studied. Brass and stainless steel wer...Significance of body material and temperature variation on burning time and burning rate of Si/Pb O/Pb_3O_4/FG and B/BaCrO_4/FG pyrotechnic delay compositions were experimentally studied. Brass and stainless steel were used as delay body materials. High resolution oscilloscope and a customized chronometer were simultaneously used for the measurement of burning time and burning rate. Results reveal that brass material with controlled column dimensions reduced the variation in burning time of Si/Pb O/Pb_3O_4/FG delay mixture from 7.43% to 4.17% and that of B/Ba CrO_4/FG mixture from 16.83% to 9.39%.Similarly the variation in burning rate was reduced from 7.57% to 4.12% and from 17% to 9.69% for Si/Pb O/Pb_3O_4/FG and B/BaCrO_4/FG mixtures respectively. Si/PbO/Pb_3O_4/FG delay mixture was also subjected to temperature ranging from -54℃ up to+100℃. The burning rate of this composition varied linearly with temperature. Burning rate increased from 28.01 mm/s to 34.38 mm/s when the temperature was varied from -54℃ to +100℃.展开更多
采用粉末冶金模压烧结制备了Ti-15Mo/HA生物复合材料,研究了羟基磷灰石(HA)对复合材料的微观结构、显微硬度及摩擦磨损性能的影响。结果表明,随着HA含量的增加,Ti-15Mo/HA复合材料中的α-Ti增加、β-Ti减少,同时有多种陶瓷相(CaTiO_(3)...采用粉末冶金模压烧结制备了Ti-15Mo/HA生物复合材料,研究了羟基磷灰石(HA)对复合材料的微观结构、显微硬度及摩擦磨损性能的影响。结果表明,随着HA含量的增加,Ti-15Mo/HA复合材料中的α-Ti增加、β-Ti减少,同时有多种陶瓷相(CaTiO_(3)、Ca_(3)(PO_(4))_(2)、CaO等)生成。加入HA生成的多种硬质陶瓷相使得Ti-15Mo/HA复合材料的维氏硬度提高。由于Mo在Ti中的固溶强化和陶瓷相的弥散强化,以及液体的润滑作用,Ti-15Mo/HA复合材料在模拟体液(simulated body fluid,SBF)环境下的摩擦因数和磨损率较低。Ti-15Mo/5HA比其他复合材料具有更好的耐磨性能,其平均摩擦因数为0.42,磨损率约为2.51×10^(-4)mm^(3)/(N·m)。Ti-15Mo合金是黏着磨损和磨粒磨损共同作用,而Ti-15Mo/HA复合材料以磨粒磨损为主,黏着磨损为辅。粉末冶金制备的Ti-15Mo/5HA复合材料显示了良好的耐磨性能,在硬组织替代和修复材料领域具有潜在的应用前景。展开更多
The woven basalt fiber composites(WBFC) and the unidirectional [0°/90°/45°/-45°]s basalt fiber composites(UBFC) were prepared by hot-pressing.Three-point bending test,low velocity impact test,and b...The woven basalt fiber composites(WBFC) and the unidirectional [0°/90°/45°/-45°]s basalt fiber composites(UBFC) were prepared by hot-pressing.Three-point bending test,low velocity impact test,and ballistic test were performed to the prepared composites.After the tests,the specimens were recovered and analyzed for micromorphology.Three-point bending tests show that both the bending strength and stiffness of the WBFC surpass those of the UBFC.Low velocity impact test results show that the low velocity impact resistance to hemispherical impactor of the UBFC is higher than that of the WBFC,but the low velocity impact resistance to sharp impactor of the UBFC is lower than that of the WBFC.For the ballistic test,it can be found that the ballistic property of the UBFC is higher than that of the WBFC. After the tests,microscopic analysis of the specimens was applied,and their failure mechanism was discussed.The main failure modes of the UBFC are delamination and fibers breakage under the above loading conditions while the main failure mode of the WBFC is fibers breakage.Although delamination damage can be found in the WBFC under the above loading conditions,the degree of delamination is far less than that of the UBFC.展开更多
Direct carbon solid oxide fuel cells(DC-SOFCs)are promising,green,and efficient power-generating devices that are fueled by solid carbons and comprise all-solid-state structures.Developing suitable anode materials for...Direct carbon solid oxide fuel cells(DC-SOFCs)are promising,green,and efficient power-generating devices that are fueled by solid carbons and comprise all-solid-state structures.Developing suitable anode materials for DC-SOFCs is a substantial scientific challenge.Herein we investigated the use of La_(0.75)Sr_(0.25)Cr_(0.5)Mn_(0.5)O_(3)-δ−Ce_(0.8)Gd_(0.2)O_(1.9)(LSCM−GDC)composite electrodes as anodes for La_(0.9)Sr_(0.1)Ga_(0.8)Mg_(0.2)O_(3)-δelectrolyte-based DC-SOFCs,with Camellia oleifera shell char as the carbon fuel.The LSCM−GDC-anode DC-SOFC delivered a maximum power density of 221 mW/cm^(2) at 800℃ and it significantly improved to 425 mW/cm^(2) after Ni nanoparticles were introduced into the LSCM−GDC anode through wet impregnation.The microstructures of the prepared anodes were characterized,and the stability of the anode in a DC-SOFC and the influence of catalytic activity on open circuit voltage were studied.The above results indicate that LSCM–GDC anode is promising to be applied in DC-SOFCs.展开更多
背景伴有超重或肥胖的2型糖尿病是一种日益严重的全球公共卫生问题,患者常伴有胰岛素抵抗、代谢异常及慢性炎症。尽管运动干预被广泛认为能改善这些状况,但同期有氧与抗阻训练对伴有超重或肥胖的2型糖尿病患者的具体效果及其机制尚存在...背景伴有超重或肥胖的2型糖尿病是一种日益严重的全球公共卫生问题,患者常伴有胰岛素抵抗、代谢异常及慢性炎症。尽管运动干预被广泛认为能改善这些状况,但同期有氧与抗阻训练对伴有超重或肥胖的2型糖尿病患者的具体效果及其机制尚存在争议。目的通过Meta分析评估同期训练对伴有超重或肥胖的2型糖尿病患者身体成分、心肺耐力、糖脂代谢、炎症因子指标的效果,为该类人群非药物无创疗法的制订提供参考。方法检索PubMed、Web of Science、Ebsco、Embase、中国知网、维普网、万方数据知识服务平台、中国生物医学文献数据库,检索同期训练运动对伴有超重或肥胖的2型糖尿病患者身体成分、心肺耐力、脂质代谢、糖尿病相关代谢标志物、炎症因子相关指标干预效果的随机对照试验,检索时间范围为2001年1月—2024年3月。基于Cochrane风险偏倚评估工具评估纳入文献质量,Meta分析由Stata16.0软件完成。结果共纳入12项随机对照试验,包括967例伴有超重或肥胖的2型糖尿病患者。Meta分析结果显示,与对照组相比,同期训练运动干预组身体成分[BMI:WMD=-0.46,P<0.001;体脂百分比(BF%):WMD=-3.49,P<0.001;去脂体质量(FFM%):WMD=3.26,P<0.001;腰围(WC):WMD=-2.73,P<0.001;臀围(HC):WMD=-2.78,P<0.001]、心肺耐力[最大摄氧量(VO_(2max)):WMD=3.85,P<0.001]、脂质代谢[三酰甘油(TG):SMD=-1.48,P=0.007;总胆固醇(TC):SMD=-1.66,P=0.002;高密度脂蛋白胆固醇(HDL-C):SMD=1.10,P=0.011;低密度脂蛋白胆固醇(LDL-C):SMD=-1.26,P=0.018]、糖尿病代谢标志物[糖化血红蛋白(HbA_(1c)):WMD=-0.86,P<0.001;胰岛素抵抗指数(HOMA-IR):SMD=-0.97,P<0.004;血糖(Glucose):SMD=-1.32,P=0.014]、炎症标志物[肿瘤坏死因子α(TNF-α):SMD=-1.98,P<0.001]显著改善。结论同期训练可显著改善伴有超重或肥胖2型糖尿病患者体质健康相关结局指标,包括BMI、BF%、FFM%、WC、HC、VO_(2max)、TG、TC、HDL-C、LDL-C、HbA_(1c)、HOMA-IR、TNF-α,具体干预效果受训练总量及训练顺序影响。展开更多
文摘Objective To establish a body composition analysis system based on chest CT,and to observe its value for evaluating content of chest muscle and adipose.Methods T7—T8 layer CT images of 108 pneumonia patients were collected(segmented dataset),and chest CT data of 984 patients were screened from the COVID 19-CT dataset(10 cases were randomly selected as whole test dataset,the remaining 974 cases were selected as layer selection dataset).T7—T8 layer was classified based on convolutional neural network(CNN)derived networks,including ResNet,ResNeXt,MobileNet,ShuffleNet,DenseNet,EfficientNet and ConvNeXt,then the accuracy,precision,recall and specificity were used to evaluate the performance of layer selection dataset.The skeletal muscle(SM),subcutaneous adipose tissue(SAT),intermuscular adipose tissue(IMAT)and visceral adipose tissue(VAT)were segmented using classical fully CNN(FCN)derived network,including FCN,SegNet,UNet,Attention UNet,UNET++,nnUNet,UNeXt and CMUNeXt,then Dice similarity coefficient(DSC),intersection over union(IoU)and 95 Hausdorff distance(HD)were used to evaluate the performance of segmented dataset.The automatic body composition analysis system was constructed based on optimal layer selection network and segmentation network,the mean absolute error(MAE),root mean squared error(RMSE)and standard deviation(SD)of MAE were used to evaluate the performance of automatic system for testing the whole test dataset.Results The accuracy,precision,recall and specificity of DenseNet network for automatically classifying T7—T8 layer from chest CT images was 95.06%,84.83%,92.27%and 95.78%,respectively,which were all higher than those of the other layer selection networks.In segmentation of SM,SAT,IMAT and overall,DSC and IoU of UNet++network were all higher,while 95HD of UNet++network were all lower than those of the other segmentation networks.Using DenseNet as the layer selection network and UNet++as the segmentation network,MAE of the automatic body composition analysis system for predicting SM,SAT,IMAT,VAT and MAE was 27.09,6.95,6.65 and 3.35 cm 2,respectively.Conclusion The body composition analysis system based on chest CT could be used to assess content of chest muscle and adipose.Among them,the UNet++network had better segmentation performance in adipose tissue than SM.
文摘Significance of body material and temperature variation on burning time and burning rate of Si/Pb O/Pb_3O_4/FG and B/BaCrO_4/FG pyrotechnic delay compositions were experimentally studied. Brass and stainless steel were used as delay body materials. High resolution oscilloscope and a customized chronometer were simultaneously used for the measurement of burning time and burning rate. Results reveal that brass material with controlled column dimensions reduced the variation in burning time of Si/Pb O/Pb_3O_4/FG delay mixture from 7.43% to 4.17% and that of B/Ba CrO_4/FG mixture from 16.83% to 9.39%.Similarly the variation in burning rate was reduced from 7.57% to 4.12% and from 17% to 9.69% for Si/Pb O/Pb_3O_4/FG and B/BaCrO_4/FG mixtures respectively. Si/PbO/Pb_3O_4/FG delay mixture was also subjected to temperature ranging from -54℃ up to+100℃. The burning rate of this composition varied linearly with temperature. Burning rate increased from 28.01 mm/s to 34.38 mm/s when the temperature was varied from -54℃ to +100℃.
文摘采用粉末冶金模压烧结制备了Ti-15Mo/HA生物复合材料,研究了羟基磷灰石(HA)对复合材料的微观结构、显微硬度及摩擦磨损性能的影响。结果表明,随着HA含量的增加,Ti-15Mo/HA复合材料中的α-Ti增加、β-Ti减少,同时有多种陶瓷相(CaTiO_(3)、Ca_(3)(PO_(4))_(2)、CaO等)生成。加入HA生成的多种硬质陶瓷相使得Ti-15Mo/HA复合材料的维氏硬度提高。由于Mo在Ti中的固溶强化和陶瓷相的弥散强化,以及液体的润滑作用,Ti-15Mo/HA复合材料在模拟体液(simulated body fluid,SBF)环境下的摩擦因数和磨损率较低。Ti-15Mo/5HA比其他复合材料具有更好的耐磨性能,其平均摩擦因数为0.42,磨损率约为2.51×10^(-4)mm^(3)/(N·m)。Ti-15Mo合金是黏着磨损和磨粒磨损共同作用,而Ti-15Mo/HA复合材料以磨粒磨损为主,黏着磨损为辅。粉末冶金制备的Ti-15Mo/5HA复合材料显示了良好的耐磨性能,在硬组织替代和修复材料领域具有潜在的应用前景。
基金supported by the National Science Foundation of China(No.51571033)supported in part by the National Natural Science Foundation of China under Grant No.11521062。
文摘The woven basalt fiber composites(WBFC) and the unidirectional [0°/90°/45°/-45°]s basalt fiber composites(UBFC) were prepared by hot-pressing.Three-point bending test,low velocity impact test,and ballistic test were performed to the prepared composites.After the tests,the specimens were recovered and analyzed for micromorphology.Three-point bending tests show that both the bending strength and stiffness of the WBFC surpass those of the UBFC.Low velocity impact test results show that the low velocity impact resistance to hemispherical impactor of the UBFC is higher than that of the WBFC,but the low velocity impact resistance to sharp impactor of the UBFC is lower than that of the WBFC.For the ballistic test,it can be found that the ballistic property of the UBFC is higher than that of the WBFC. After the tests,microscopic analysis of the specimens was applied,and their failure mechanism was discussed.The main failure modes of the UBFC are delamination and fibers breakage under the above loading conditions while the main failure mode of the WBFC is fibers breakage.Although delamination damage can be found in the WBFC under the above loading conditions,the degree of delamination is far less than that of the UBFC.
基金Project(2019YFC1907405)supported by the National Key R&D Program of ChinaProject(GJJ200809)supported by the Education Department Project Fund of Jiangxi Province,ChinaProject(2020BAB214021)supported by the Natural Science Foundation of Jiangxi Province,China。
文摘Direct carbon solid oxide fuel cells(DC-SOFCs)are promising,green,and efficient power-generating devices that are fueled by solid carbons and comprise all-solid-state structures.Developing suitable anode materials for DC-SOFCs is a substantial scientific challenge.Herein we investigated the use of La_(0.75)Sr_(0.25)Cr_(0.5)Mn_(0.5)O_(3)-δ−Ce_(0.8)Gd_(0.2)O_(1.9)(LSCM−GDC)composite electrodes as anodes for La_(0.9)Sr_(0.1)Ga_(0.8)Mg_(0.2)O_(3)-δelectrolyte-based DC-SOFCs,with Camellia oleifera shell char as the carbon fuel.The LSCM−GDC-anode DC-SOFC delivered a maximum power density of 221 mW/cm^(2) at 800℃ and it significantly improved to 425 mW/cm^(2) after Ni nanoparticles were introduced into the LSCM−GDC anode through wet impregnation.The microstructures of the prepared anodes were characterized,and the stability of the anode in a DC-SOFC and the influence of catalytic activity on open circuit voltage were studied.The above results indicate that LSCM–GDC anode is promising to be applied in DC-SOFCs.
文摘背景伴有超重或肥胖的2型糖尿病是一种日益严重的全球公共卫生问题,患者常伴有胰岛素抵抗、代谢异常及慢性炎症。尽管运动干预被广泛认为能改善这些状况,但同期有氧与抗阻训练对伴有超重或肥胖的2型糖尿病患者的具体效果及其机制尚存在争议。目的通过Meta分析评估同期训练对伴有超重或肥胖的2型糖尿病患者身体成分、心肺耐力、糖脂代谢、炎症因子指标的效果,为该类人群非药物无创疗法的制订提供参考。方法检索PubMed、Web of Science、Ebsco、Embase、中国知网、维普网、万方数据知识服务平台、中国生物医学文献数据库,检索同期训练运动对伴有超重或肥胖的2型糖尿病患者身体成分、心肺耐力、脂质代谢、糖尿病相关代谢标志物、炎症因子相关指标干预效果的随机对照试验,检索时间范围为2001年1月—2024年3月。基于Cochrane风险偏倚评估工具评估纳入文献质量,Meta分析由Stata16.0软件完成。结果共纳入12项随机对照试验,包括967例伴有超重或肥胖的2型糖尿病患者。Meta分析结果显示,与对照组相比,同期训练运动干预组身体成分[BMI:WMD=-0.46,P<0.001;体脂百分比(BF%):WMD=-3.49,P<0.001;去脂体质量(FFM%):WMD=3.26,P<0.001;腰围(WC):WMD=-2.73,P<0.001;臀围(HC):WMD=-2.78,P<0.001]、心肺耐力[最大摄氧量(VO_(2max)):WMD=3.85,P<0.001]、脂质代谢[三酰甘油(TG):SMD=-1.48,P=0.007;总胆固醇(TC):SMD=-1.66,P=0.002;高密度脂蛋白胆固醇(HDL-C):SMD=1.10,P=0.011;低密度脂蛋白胆固醇(LDL-C):SMD=-1.26,P=0.018]、糖尿病代谢标志物[糖化血红蛋白(HbA_(1c)):WMD=-0.86,P<0.001;胰岛素抵抗指数(HOMA-IR):SMD=-0.97,P<0.004;血糖(Glucose):SMD=-1.32,P=0.014]、炎症标志物[肿瘤坏死因子α(TNF-α):SMD=-1.98,P<0.001]显著改善。结论同期训练可显著改善伴有超重或肥胖2型糖尿病患者体质健康相关结局指标,包括BMI、BF%、FFM%、WC、HC、VO_(2max)、TG、TC、HDL-C、LDL-C、HbA_(1c)、HOMA-IR、TNF-α,具体干预效果受训练总量及训练顺序影响。
