Chilling is one of the major abiotic stresses limiting yield and quality of many important crops. For better understanding of chilling stress responses in tobacco （Nicotiana tabacum）, growth rate and antioxidant enz...Chilling is one of the major abiotic stresses limiting yield and quality of many important crops. For better understanding of chilling stress responses in tobacco （Nicotiana tabacum）, growth rate and antioxidant enzymes of seedlings in 2 tobacco cultivars, viz., MSk326 （chilling sensitive variety） and Honghuadajinyuan （HHDJY, chilling tolerant variety） at chilling temperature （5℃） were studied. The results showed that the relative growth rate in chilling period to that in recovery period was significantly higher in roots than that in shoots for both cultivars, suggesting that shoots growth was more easily affected by chilling stress. Chilling stress increased peroxidase （POD） activity and reduced superoxide dismutase （SOD） activity in shoots of HHDJY, and catalase （CAT） activity was little affected. In the roots of HHDJY, chilling stress increased SOD and CAT activities, and had little effect on POD activity. For MSk326, chilling treatment increased SOD activity in shoots and declined CAT activity in roots. MDA concentration in both varieties was increased under the chilling stress, while it was decreased after seedlings were recovered growth for 4 d at normal temperature （25℃）. It showed that tobacco seedlings might have the capacity of recovering from chilling injury for a short term, The relationship between the growth rate and antioxidant enzyme activity was analyzed by stepwise regression. It was found that there was a close relationship between relative growth rate of tobacco seedlings and CAT activity under chilling stress condition and regression equations containing CAT could be used in predicting seedling growth rate of tobacco under chilling stress condition.展开更多
The structural and electronic properties of monovacancy,divacancy defects within crystalline silicon have been investigated systematically using a new tight-binding model with a 216-atom supercell.The formation energi...The structural and electronic properties of monovacancy,divacancy defects within crystalline silicon have been investigated systematically using a new tight-binding model with a 216-atom supercell.The formation energies and energy levels of all the defect configurations are carefully calculated.The results show that atoms nearer to the defects naturally contribute to gap states more,and are comparable with the experimental values.展开更多
目的探讨早发型子痫前期(early onset pre-eclampsia,EOSP)患者血清内皮细胞特异性分子-1(endothelial cell specific molecule-1,ESM1)及低密度脂蛋白受体相关蛋白-1(low-density lipoprotein receptor-related protein-1,LRP1)水平及...目的探讨早发型子痫前期(early onset pre-eclampsia,EOSP)患者血清内皮细胞特异性分子-1(endothelial cell specific molecule-1,ESM1)及低密度脂蛋白受体相关蛋白-1(low-density lipoprotein receptor-related protein-1,LRP1)水平及与病情严重程度的相关性。方法选取2019年2月~2021年2月盐城市妇幼保健院218例早发型子痫前期患者为研究对象(病例组),根据病情分为轻度组(n=117)和重度组(n=101),以同期健康体检的80例健康孕妇为对照组。比较各组血清ESM1和LRP1水平。采用多因素Logistic回归分析早发型子痫前期病情严重程度的影响因素。绘制受试者工作曲线分析血清ESM1和LRP1对早发型重度子痫前期的诊断价值。结果病例组血清ESM1(323.05±45.17 mmol/L),LRP1(12.25±0.97μg/ml)水平高于对照组(195.20±31.67 mmol/L,6.41±0.84μg/ml),差异具有统计学意义(t=23.291,47.677,均P<0.05)。重度组患者血清ESM1(672.44±83.61 pg/ml),血清LRP1(14.52±1.05μg/ml)、舒张压(113.17±12.24mmHg)、收缩压(165.19±16.63mmHg)、24h尿蛋白量(2.63±0.45g/24h)、血肌酐(74.47±20.82μmol/L)、血尿素氮(4.32±0.78mmol/L)、血尿酸(339.65±50.13μmol/L)高于轻度组(551.74±72.20 pg/ml,9.63±0.89μg/ml,92.41±9.29mmHg,147.25±14.66mmHg,1.42±0.33g/24h,69.64±15.07μmol/L,3.95±0.91mmol/L,303.82±41.71μmol/L),新生儿体质量低于轻度组(2.73±0.62 kg vs 3.20±0.62 kg),差异具有统计学意义(t=1.980~37.978,均P<0.05)。病例组患者血清ESM1及LRP1水平与舒张压、收缩压、24h尿蛋白定量、血肌酐、血尿素氮及血尿酸呈正相关(r=0.413~0.515,均P<0.05),与胎儿体质量呈负相关(r=-0.563,-0.604,均P<0.05)。高血清ESM1水平(OR=1.217,95%CI:1.036~1.429)和高血清LRP1水平(OR=1.486,95%CI:1.056~2.090)是影响早发型重度子痫前期发生的独立危险因素。血清ESM1联合LRP1诊断早发型重度子痫前期的曲线下面积(area under the curve,AUC)0.884(0.853~0.916)大于ESM1(AUC=0.749,95%CI:0.705~0.792)和LRP1(AUC=0.760,95%CI:0.712~0.807)单独诊断(Z=6.752,4.297,均P<0.05)。结论早发型子痫前期患者血清ESM1和LRP1水平升高,二者均与早发型子痫前期疾病严重程度有关,联合检测能提高早发型重度子痫前期的诊断效能。展开更多
攀枝花市矿产资源丰富,采矿历史悠久,开采活动强度大,地质结构复杂,生态环境脆弱,矿山地质灾害频发.基于2019年的三江(怒江,澜沧江,金沙江)北段矿产开发环境遥感监测调查资料,在分析矿山地质灾害发育规律与影响因素关系的基础上,选取坡...攀枝花市矿产资源丰富,采矿历史悠久,开采活动强度大,地质结构复杂,生态环境脆弱,矿山地质灾害频发.基于2019年的三江(怒江,澜沧江,金沙江)北段矿产开发环境遥感监测调查资料,在分析矿山地质灾害发育规律与影响因素关系的基础上,选取坡度、工程地质岩组、距断层的距离、降水量、植被覆盖度、距河流的距离以及距开采活动面的距离7个评价因子,借助ArcGIS软件平台,采用确定性系数(Certainty Factor,CF)模型、信息量模型以及CF与信息量耦合模型开展攀枝花市矿山地质灾害易发性评价研究.结果表明,工程地质岩组、植被覆盖度、距开采活动面的距离是影响矿山地质灾害分布的控制因子;经过ROC(Receiver Operating Characteristic Curve,ROC)曲线检验,CF与信息量耦合模型的AUC(Area Under the Curve,AUC)值高达0.909,表明耦合模型比单一模型的评价精度高,其精度为耦合模型>信息量模型>确定性系数模型;耦合模型的易发性分区为极高易发区(5.24%)、高易发区(11.67%)、中易发区(41.66%)和低易发区(41.43%),其中极高和高易发区主要分布在开采活动强度较大的煤矿、铁矿和花岗岩矿矿山,即主要分布在仁和区、东区、盐边县和米易县.展开更多
基金supported by the Yunnan Province Tobacco Company, China (07A02)the Science and Technology Special Project of Zhejiang Province, China(2008C12005-1)the Special Project of Ministry of Agriculture, China (2008ZX08005-005)
文摘Chilling is one of the major abiotic stresses limiting yield and quality of many important crops. For better understanding of chilling stress responses in tobacco （Nicotiana tabacum）, growth rate and antioxidant enzymes of seedlings in 2 tobacco cultivars, viz., MSk326 （chilling sensitive variety） and Honghuadajinyuan （HHDJY, chilling tolerant variety） at chilling temperature （5℃） were studied. The results showed that the relative growth rate in chilling period to that in recovery period was significantly higher in roots than that in shoots for both cultivars, suggesting that shoots growth was more easily affected by chilling stress. Chilling stress increased peroxidase （POD） activity and reduced superoxide dismutase （SOD） activity in shoots of HHDJY, and catalase （CAT） activity was little affected. In the roots of HHDJY, chilling stress increased SOD and CAT activities, and had little effect on POD activity. For MSk326, chilling treatment increased SOD activity in shoots and declined CAT activity in roots. MDA concentration in both varieties was increased under the chilling stress, while it was decreased after seedlings were recovered growth for 4 d at normal temperature （25℃）. It showed that tobacco seedlings might have the capacity of recovering from chilling injury for a short term, The relationship between the growth rate and antioxidant enzyme activity was analyzed by stepwise regression. It was found that there was a close relationship between relative growth rate of tobacco seedlings and CAT activity under chilling stress condition and regression equations containing CAT could be used in predicting seedling growth rate of tobacco under chilling stress condition.
基金Supported by the National Natural Science Foundation of China under Grant No.69876035,the Fund of Chinese Academy of Sciences and the Fund of University of Science and Technology of China.
文摘The structural and electronic properties of monovacancy,divacancy defects within crystalline silicon have been investigated systematically using a new tight-binding model with a 216-atom supercell.The formation energies and energy levels of all the defect configurations are carefully calculated.The results show that atoms nearer to the defects naturally contribute to gap states more,and are comparable with the experimental values.
文摘目的探讨早发型子痫前期(early onset pre-eclampsia,EOSP)患者血清内皮细胞特异性分子-1(endothelial cell specific molecule-1,ESM1)及低密度脂蛋白受体相关蛋白-1(low-density lipoprotein receptor-related protein-1,LRP1)水平及与病情严重程度的相关性。方法选取2019年2月~2021年2月盐城市妇幼保健院218例早发型子痫前期患者为研究对象(病例组),根据病情分为轻度组(n=117)和重度组(n=101),以同期健康体检的80例健康孕妇为对照组。比较各组血清ESM1和LRP1水平。采用多因素Logistic回归分析早发型子痫前期病情严重程度的影响因素。绘制受试者工作曲线分析血清ESM1和LRP1对早发型重度子痫前期的诊断价值。结果病例组血清ESM1(323.05±45.17 mmol/L),LRP1(12.25±0.97μg/ml)水平高于对照组(195.20±31.67 mmol/L,6.41±0.84μg/ml),差异具有统计学意义(t=23.291,47.677,均P<0.05)。重度组患者血清ESM1(672.44±83.61 pg/ml),血清LRP1(14.52±1.05μg/ml)、舒张压(113.17±12.24mmHg)、收缩压(165.19±16.63mmHg)、24h尿蛋白量(2.63±0.45g/24h)、血肌酐(74.47±20.82μmol/L)、血尿素氮(4.32±0.78mmol/L)、血尿酸(339.65±50.13μmol/L)高于轻度组(551.74±72.20 pg/ml,9.63±0.89μg/ml,92.41±9.29mmHg,147.25±14.66mmHg,1.42±0.33g/24h,69.64±15.07μmol/L,3.95±0.91mmol/L,303.82±41.71μmol/L),新生儿体质量低于轻度组(2.73±0.62 kg vs 3.20±0.62 kg),差异具有统计学意义(t=1.980~37.978,均P<0.05)。病例组患者血清ESM1及LRP1水平与舒张压、收缩压、24h尿蛋白定量、血肌酐、血尿素氮及血尿酸呈正相关(r=0.413~0.515,均P<0.05),与胎儿体质量呈负相关(r=-0.563,-0.604,均P<0.05)。高血清ESM1水平(OR=1.217,95%CI:1.036~1.429)和高血清LRP1水平(OR=1.486,95%CI:1.056~2.090)是影响早发型重度子痫前期发生的独立危险因素。血清ESM1联合LRP1诊断早发型重度子痫前期的曲线下面积(area under the curve,AUC)0.884(0.853~0.916)大于ESM1(AUC=0.749,95%CI:0.705~0.792)和LRP1(AUC=0.760,95%CI:0.712~0.807)单独诊断(Z=6.752,4.297,均P<0.05)。结论早发型子痫前期患者血清ESM1和LRP1水平升高,二者均与早发型子痫前期疾病严重程度有关,联合检测能提高早发型重度子痫前期的诊断效能。
文摘攀枝花市矿产资源丰富,采矿历史悠久,开采活动强度大,地质结构复杂,生态环境脆弱,矿山地质灾害频发.基于2019年的三江(怒江,澜沧江,金沙江)北段矿产开发环境遥感监测调查资料,在分析矿山地质灾害发育规律与影响因素关系的基础上,选取坡度、工程地质岩组、距断层的距离、降水量、植被覆盖度、距河流的距离以及距开采活动面的距离7个评价因子,借助ArcGIS软件平台,采用确定性系数(Certainty Factor,CF)模型、信息量模型以及CF与信息量耦合模型开展攀枝花市矿山地质灾害易发性评价研究.结果表明,工程地质岩组、植被覆盖度、距开采活动面的距离是影响矿山地质灾害分布的控制因子;经过ROC(Receiver Operating Characteristic Curve,ROC)曲线检验,CF与信息量耦合模型的AUC(Area Under the Curve,AUC)值高达0.909,表明耦合模型比单一模型的评价精度高,其精度为耦合模型>信息量模型>确定性系数模型;耦合模型的易发性分区为极高易发区(5.24%)、高易发区(11.67%)、中易发区(41.66%)和低易发区(41.43%),其中极高和高易发区主要分布在开采活动强度较大的煤矿、铁矿和花岗岩矿矿山,即主要分布在仁和区、东区、盐边县和米易县.
