In artificially controlled pot experiments,perennial ryegrass was mixed with other leguminous plants(white clo-ver and alfalfa)and treated with lead,zinc and cadmium(337 mg·kg^(-1),648 mg·kg^(-1),and 9 mg...In artificially controlled pot experiments,perennial ryegrass was mixed with other leguminous plants(white clo-ver and alfalfa)and treated with lead,zinc and cadmium(337 mg·kg^(-1),648 mg·kg^(-1),and 9 mg·kg^(-1),respectively)to simulate compound pollution conditions.The results showed that the concentrations of heavy metals,trans-port factors,and bioconcentration factors in mixed planting of ryegrass decreased compared with those in mono-culture.Regardless of whether heavy metal pollution was introduced,mixed planting increased the aboveground and underground biomasses of ryegrass.The different mixed planting treatments had no significant impact on the chlorophyll concentration of ryegrass.The mowing time,mixed planting treatment,and heavy metal treatment had impacts on antioxidant and osmotic adjustment substances,and there were some interactions.The mixed planting treatment did not significantly affect glutathione concentration,cysteine concentration,or nonprotein thiol.Mixed planting generally increased the nitrogen and phosphorus concentrations of ryegrass while reducing the stoichiometric ratio of carbon,nitrogen,and phosphorus.These results suggest that the mixed planting of ryegrass with legumes promotes the growth of ryegrass in the presence of high concentrations of heavy metal pollution.However,it does not enhance the ability of ryegrass to remediate heavy metal pollution in the soil.展开更多
近年来使用GNSS(global navigation satellite system)反射信号反演土壤湿度已成为研究热点,使用星载反射计数据反演土壤湿度是一种有潜力的新兴技术。以TDS-1(technology demonstrate satellite-1)卫星接收的数据为例,首先推导出反射...近年来使用GNSS(global navigation satellite system)反射信号反演土壤湿度已成为研究热点,使用星载反射计数据反演土壤湿度是一种有潜力的新兴技术。以TDS-1(technology demonstrate satellite-1)卫星接收的数据为例,首先推导出反射信号功率 P r与土壤湿度 M v间的理论关系,然后将SMAP(soil moisture active passive)卫星获得的 M v作为标准值,在空间上选择两条轨迹的 P r与 M v进行皮尔森相关处理,得到两条轨迹上的相关系数分别为0.55和0.60。之后对 P r和 M v分别进行相应的平滑预处理去除噪声,得到相关系数都增加为0.71,即 P r与土壤湿度强相关。取春夏秋冬四个季节的数据,计算 P r与 M v的相关系数为0.78,二者也表现为强相关。实验结果表明:星载(GNSS-reflections,GNSS-R)接收机得到的 P r与 M v有很强的相关性,具有估计土壤湿度的潜力。展开更多
目的研究诊断决策支持工具Kaiser评分系统中不同评分界值应用于乳腺病变MRI诊断中的效能,探索良恶性病变最佳参考评分界值从而避免过度的乳腺活检,并与传统的BI-RADS分类诊断标准进行诊断效能的比较。方法回顾并分析来自92例患者共101...目的研究诊断决策支持工具Kaiser评分系统中不同评分界值应用于乳腺病变MRI诊断中的效能,探索良恶性病变最佳参考评分界值从而避免过度的乳腺活检,并与传统的BI-RADS分类诊断标准进行诊断效能的比较。方法回顾并分析来自92例患者共101个术前行乳腺1.5 T MRI检查并被手术或穿刺病理证实的病灶的临床资料,由2位中级职称的影像科医生对所有病例独立根据Kaiser评分系统给出评分,探讨Kaiser评分系统应用于乳腺病变MRI中的诊断效能并与传统的BI-RADS分类诊断进行诊断效能比较,统计Kaiser评分在不同临界值下的敏感度、特异性和似然比,并分析2位阅片者之间的Kaiser评分一致性。结果92例患者共101个病灶,病理证实其中恶性病灶34个(33.66%),良性病灶67个(66.34%);应用Kaiser评分系统的曲线下面积值为0.969,BI-RADS分类的曲线下面积值为0.702,两种诊断方法的诊断效能差异有统计学意义(P<0.01),分别使用临界值≥4、≥5、≥6做为良恶性病变的分界值,可以准确识别100.00%、100.00%、91.98%的恶性病变,特异度分别为79.10%、80.60%、88.06%,以高截断值≥7分作为判断良恶性病变的参考界值,可以正确识别79.41%的恶性病变,特异性为98.51%,阳性似然比为53.21。2位阅片者之间的Kaiser评分一致性良好(Kappa值=0.89,P<0.01)。结论在乳腺病变MRI诊断中应用Kaiser评分对提高诊断准确性有益,同时以≥5为判断良恶性病变的诊断界值,可以获得最佳的综合诊断效能,针对特定诊断目标,在Kaiser评分中合理运用高诊断界值,可最大程度地避免过度乳腺活检。展开更多
基金funded through projects of the National Key Research and Development Program of China(2023YFD1301401)Cheng Wei received the grant.Ministry of Science and Technology of the People’s Republic of China(https://www.most.gov.cn/index.html,accessed on 19/03/2024)+1 种基金And the Guizhou Provincial Science and Technology Projects(QKHPTRC-CXTD[2022]1011)Chao Chen received the grant.Guizhou Provincial Department of Science and Technology(https://kjt.guizhou.gov.cn/,accessed on 19/03/2024).
文摘In artificially controlled pot experiments,perennial ryegrass was mixed with other leguminous plants(white clo-ver and alfalfa)and treated with lead,zinc and cadmium(337 mg·kg^(-1),648 mg·kg^(-1),and 9 mg·kg^(-1),respectively)to simulate compound pollution conditions.The results showed that the concentrations of heavy metals,trans-port factors,and bioconcentration factors in mixed planting of ryegrass decreased compared with those in mono-culture.Regardless of whether heavy metal pollution was introduced,mixed planting increased the aboveground and underground biomasses of ryegrass.The different mixed planting treatments had no significant impact on the chlorophyll concentration of ryegrass.The mowing time,mixed planting treatment,and heavy metal treatment had impacts on antioxidant and osmotic adjustment substances,and there were some interactions.The mixed planting treatment did not significantly affect glutathione concentration,cysteine concentration,or nonprotein thiol.Mixed planting generally increased the nitrogen and phosphorus concentrations of ryegrass while reducing the stoichiometric ratio of carbon,nitrogen,and phosphorus.These results suggest that the mixed planting of ryegrass with legumes promotes the growth of ryegrass in the presence of high concentrations of heavy metal pollution.However,it does not enhance the ability of ryegrass to remediate heavy metal pollution in the soil.
文摘近年来使用GNSS(global navigation satellite system)反射信号反演土壤湿度已成为研究热点,使用星载反射计数据反演土壤湿度是一种有潜力的新兴技术。以TDS-1(technology demonstrate satellite-1)卫星接收的数据为例,首先推导出反射信号功率 P r与土壤湿度 M v间的理论关系,然后将SMAP(soil moisture active passive)卫星获得的 M v作为标准值,在空间上选择两条轨迹的 P r与 M v进行皮尔森相关处理,得到两条轨迹上的相关系数分别为0.55和0.60。之后对 P r和 M v分别进行相应的平滑预处理去除噪声,得到相关系数都增加为0.71,即 P r与土壤湿度强相关。取春夏秋冬四个季节的数据,计算 P r与 M v的相关系数为0.78,二者也表现为强相关。实验结果表明:星载(GNSS-reflections,GNSS-R)接收机得到的 P r与 M v有很强的相关性,具有估计土壤湿度的潜力。
文摘目的研究诊断决策支持工具Kaiser评分系统中不同评分界值应用于乳腺病变MRI诊断中的效能,探索良恶性病变最佳参考评分界值从而避免过度的乳腺活检,并与传统的BI-RADS分类诊断标准进行诊断效能的比较。方法回顾并分析来自92例患者共101个术前行乳腺1.5 T MRI检查并被手术或穿刺病理证实的病灶的临床资料,由2位中级职称的影像科医生对所有病例独立根据Kaiser评分系统给出评分,探讨Kaiser评分系统应用于乳腺病变MRI中的诊断效能并与传统的BI-RADS分类诊断进行诊断效能比较,统计Kaiser评分在不同临界值下的敏感度、特异性和似然比,并分析2位阅片者之间的Kaiser评分一致性。结果92例患者共101个病灶,病理证实其中恶性病灶34个(33.66%),良性病灶67个(66.34%);应用Kaiser评分系统的曲线下面积值为0.969,BI-RADS分类的曲线下面积值为0.702,两种诊断方法的诊断效能差异有统计学意义(P<0.01),分别使用临界值≥4、≥5、≥6做为良恶性病变的分界值,可以准确识别100.00%、100.00%、91.98%的恶性病变,特异度分别为79.10%、80.60%、88.06%,以高截断值≥7分作为判断良恶性病变的参考界值,可以正确识别79.41%的恶性病变,特异性为98.51%,阳性似然比为53.21。2位阅片者之间的Kaiser评分一致性良好(Kappa值=0.89,P<0.01)。结论在乳腺病变MRI诊断中应用Kaiser评分对提高诊断准确性有益,同时以≥5为判断良恶性病变的诊断界值,可以获得最佳的综合诊断效能,针对特定诊断目标,在Kaiser评分中合理运用高诊断界值,可最大程度地避免过度乳腺活检。
