目的分析介入诊疗过程中散射线对操作人员的防护部位和暴露部位的年辐射剂量,探讨此种辐射对介入诊疗操作人员的危害及进一步加强防护措施。方法跟踪测量2015及2016年度南昌市三甲医院参与介入诊疗的100名医护人员的肘部、前臂、小腿中...目的分析介入诊疗过程中散射线对操作人员的防护部位和暴露部位的年辐射剂量,探讨此种辐射对介入诊疗操作人员的危害及进一步加强防护措施。方法跟踪测量2015及2016年度南昌市三甲医院参与介入诊疗的100名医护人员的肘部、前臂、小腿中部、足背部等未防护部位及躯干、肩部、大腿等穿戴有防护用品部位的辐射剂量进行对比并分析。结果监测南昌市三甲医院参与介入诊疗的100名医务人员情况,铅衣覆盖的躯干部位的年辐射剂量平均为0.009 m Sv,略低于本底值(科室环境本底值约为0.012 m Sv/年),肩部年辐射值0.01~0.14 m Sv,大腿部位为0.015~0.24 m Sv;暴露部位中,小腿中部及足背部年辐射剂量为0.18~2.4 m Sv,肘部和前臂以下为9~397 m Sv。其中各科技术骨干年辐射剂量均超出平均值1倍以上。防护区和暴露区比较,差异有统计学意义(P<0.05)。结论导致辐射剂量值差异的主要原因为防护服的防护作用明显及不同介入手术的辐射剂量差异较大,特别是冠脉介入技术骨干医生的前臂及以下部位年辐射剂量接近于年辐射剂量最大限值,应当进一步加强防护措施及合理安排人员轮换。展开更多
On the Loess Plateau of China, a dry soil layer may form due to excess transpiration, leading to degradation of black locust(Robinia pseudoacacia) stands. In order to better manage projects involving black locust, thi...On the Loess Plateau of China, a dry soil layer may form due to excess transpiration, leading to degradation of black locust(Robinia pseudoacacia) stands. In order to better manage projects involving black locust, this study was intended to investigate the response of black locust transpiration rate to soil water availability as affected by meteorological factors using two representative soils(loamy clay and sandy loam) on the Loess Plateau. Four soil water contents were maintained for black locust seedlings grown in pots initially outdoors and then in a climate-controlled chamber, by either drying or irrigating the pots. In both environments, daily transpiration rates were related by a power function to air temperature and by a logistic function to reference evapotranspiration(ET0). Transpiration rates were more susceptible to changes in the meteorological conditions in the sandy loam than in the loamy clay soil. The transpiration rate in the well-watered treatment was greater for black locust grown in the sandy loam than in the loamy clay soil. Normalized transpiration rates were unaffected by ET0 until a critical value of soil water content(θc) was attained; the θc value decreased significantly for the loamy clay soil but increased significantly for the sandy loam soil when ET0 increased. These suggested that the effect of the meteorological condition on the transpiration characteristics of black locust was dependent on soil texture.展开更多
Knowledge of plant responses to soil water availability is essential for the development of effcient irrigation strategies.However,notably different results have been obtained in the past on the responses of various p...Knowledge of plant responses to soil water availability is essential for the development of effcient irrigation strategies.However,notably different results have been obtained in the past on the responses of various physiological indices for different plants to soil water availability.In this study,the responses of various plant processes to soil water availability were compared with data from pot and field plot experiments conducted on maize(Zea mays L.).Consistent results were obtained between pot and field plot experiments for the responses of various relative plant indices to changes in the fraction of available soil water(FASW).A threshold value,where the relative plant indices began to decrease with soil drying,and a lower water limit,where the decline of relative plant indices changed to a very slow rate,were found.Evaporative demand not only influenced the transpiration rate over a daily scale but also determined the difference in transpirational response to soil water availability among the transient,daily and seasonal time scales.At the seasonal scale,cumulative transpiration decreased linearly with soil drying,but the decrease of transpiration from FASW = 1 in response to water deficits did not affect dry weight until FASW = 0.75.On the other hand,the decrease in dry weight was comparable with plant height and leaf area.Therefore,the plant responses to soil water availability were notably different among various plant indices of maize and were influenced by the weather conditions.展开更多
文摘目的分析介入诊疗过程中散射线对操作人员的防护部位和暴露部位的年辐射剂量,探讨此种辐射对介入诊疗操作人员的危害及进一步加强防护措施。方法跟踪测量2015及2016年度南昌市三甲医院参与介入诊疗的100名医护人员的肘部、前臂、小腿中部、足背部等未防护部位及躯干、肩部、大腿等穿戴有防护用品部位的辐射剂量进行对比并分析。结果监测南昌市三甲医院参与介入诊疗的100名医务人员情况,铅衣覆盖的躯干部位的年辐射剂量平均为0.009 m Sv,略低于本底值(科室环境本底值约为0.012 m Sv/年),肩部年辐射值0.01~0.14 m Sv,大腿部位为0.015~0.24 m Sv;暴露部位中,小腿中部及足背部年辐射剂量为0.18~2.4 m Sv,肘部和前臂以下为9~397 m Sv。其中各科技术骨干年辐射剂量均超出平均值1倍以上。防护区和暴露区比较,差异有统计学意义(P<0.05)。结论导致辐射剂量值差异的主要原因为防护服的防护作用明显及不同介入手术的辐射剂量差异较大,特别是冠脉介入技术骨干医生的前臂及以下部位年辐射剂量接近于年辐射剂量最大限值,应当进一步加强防护措施及合理安排人员轮换。
基金supported by the National Natural Science Foundation of China(Nos.41171186 and 41101206)
文摘On the Loess Plateau of China, a dry soil layer may form due to excess transpiration, leading to degradation of black locust(Robinia pseudoacacia) stands. In order to better manage projects involving black locust, this study was intended to investigate the response of black locust transpiration rate to soil water availability as affected by meteorological factors using two representative soils(loamy clay and sandy loam) on the Loess Plateau. Four soil water contents were maintained for black locust seedlings grown in pots initially outdoors and then in a climate-controlled chamber, by either drying or irrigating the pots. In both environments, daily transpiration rates were related by a power function to air temperature and by a logistic function to reference evapotranspiration(ET0). Transpiration rates were more susceptible to changes in the meteorological conditions in the sandy loam than in the loamy clay soil. The transpiration rate in the well-watered treatment was greater for black locust grown in the sandy loam than in the loamy clay soil. Normalized transpiration rates were unaffected by ET0 until a critical value of soil water content(θc) was attained; the θc value decreased significantly for the loamy clay soil but increased significantly for the sandy loam soil when ET0 increased. These suggested that the effect of the meteorological condition on the transpiration characteristics of black locust was dependent on soil texture.
基金Supported by the CAS/SAFEA International Partnership Program for Creative Research Teamsthe Knowledge Innovation Program of the Chinese Academy of Sciences (No.KSCX1-YW-09-07)the National Natural Science Foundationof China (No.40671083)
文摘Knowledge of plant responses to soil water availability is essential for the development of effcient irrigation strategies.However,notably different results have been obtained in the past on the responses of various physiological indices for different plants to soil water availability.In this study,the responses of various plant processes to soil water availability were compared with data from pot and field plot experiments conducted on maize(Zea mays L.).Consistent results were obtained between pot and field plot experiments for the responses of various relative plant indices to changes in the fraction of available soil water(FASW).A threshold value,where the relative plant indices began to decrease with soil drying,and a lower water limit,where the decline of relative plant indices changed to a very slow rate,were found.Evaporative demand not only influenced the transpiration rate over a daily scale but also determined the difference in transpirational response to soil water availability among the transient,daily and seasonal time scales.At the seasonal scale,cumulative transpiration decreased linearly with soil drying,but the decrease of transpiration from FASW = 1 in response to water deficits did not affect dry weight until FASW = 0.75.On the other hand,the decrease in dry weight was comparable with plant height and leaf area.Therefore,the plant responses to soil water availability were notably different among various plant indices of maize and were influenced by the weather conditions.
