Guiyang is a famous tourist city located in southwestern China. In this study, dust from eleven residential areas, seven city squares, and nine schools was collected to measure the heavy metal levels and evaluate its ...Guiyang is a famous tourist city located in southwestern China. In this study, dust from eleven residential areas, seven city squares, and nine schools was collected to measure the heavy metal levels and evaluate its risk. At each sampling site, 4–5 sub-samples were taken as a bulk sample. All samples were air-dried, ground, passed through a 0.105 mm nylon sieve, digested with HNO3-HClO4 to determine the concentrations of Cd, Cu, Ni, Pb and Zn by ICP-MS, and digested with 1:1 aqua regia to determine As by AFS. The results show that the concentrations of As, Cd, Cu, Ni, Pb and Zn in dust of Guiyang City follow normal distribution with means of 16.1, 1.54, 138, 47.7, 129 and 479 mg/kg, respectively. Levels of As, Cd, Cu, Ni, Pb and Zn exceed the background level of soil in Guizhou Province by 33%, 96%, 100%, 78%, 96%, and 100%, respectively. Cd, Cu, Pb and Zn are heavily accumulated in dust of living areas with accumulation factors of 4.10, 5.12, 4.12 and 5.51, respectively. City square possesses the highest geometric means of As, Cd, Cu, Pb, and Zn. The risks of heavy metal exposure to teenagers are not obvious and in an order of As>Pb>Cu>Ni>Zn(Cd).展开更多
针对带时间窗的时间依赖型同时取送货车辆路径问题(Time Dependent Vehicle Routing Problem with Simultaneous Pickup-Delivery and Time Windows,TDVRPSPDTW),本文建立以车辆固定成本、驾驶员成本、燃油消耗及碳排放成本之和为优化...针对带时间窗的时间依赖型同时取送货车辆路径问题(Time Dependent Vehicle Routing Problem with Simultaneous Pickup-Delivery and Time Windows,TDVRPSPDTW),本文建立以车辆固定成本、驾驶员成本、燃油消耗及碳排放成本之和为优化目标的数学模型;并在传统蚁群算法的基础上,利用节约启发式构造初始解初始化信息素,改进状态转移规则,引入局部搜索策略,提出一种带自适应大邻域搜索的混合蚁群算法(Ant Colony Optimization with Adaptive Large Neighborhood Search,ACO-ALNS)进行求解;最后,分别选取基准问题算例和改编生成TDVRPSPDTW算例进行实验。实验结果表明:本文提出的ACO-ALNS算法可有效解决TDVRPSPDTW的基准问题;相较于模拟退火算法和带局部搜索的蚁群算法,本文算法求解得到的总配送成本最优值平均分别改善7.56%和2.90%;另外,相比于仅考虑碳排放或配送时间的模型,本文所构建的模型综合多种因素,总配送成本平均分别降低4.38%和3.18%,可有效提高物流企业的经济效益。展开更多
目的:观察探讨0.03%他克莫司软膏联合多磺酸粘多糖乳膏治疗面部单纯糠疹的美学效果。方法:选取2019年11月-2022年1月门诊收治的105例面部单纯糠疹患儿为观察对象,通过随机数字法随机分为联合组(n=53)和对照组(n=52),对照组给予多磺酸粘...目的:观察探讨0.03%他克莫司软膏联合多磺酸粘多糖乳膏治疗面部单纯糠疹的美学效果。方法:选取2019年11月-2022年1月门诊收治的105例面部单纯糠疹患儿为观察对象,通过随机数字法随机分为联合组(n=53)和对照组(n=52),对照组给予多磺酸粘多糖乳膏治疗,联合组在对照组基础上加用0.03%他克莫司软膏治疗,比较两组治疗后的临床疗效、症状体征评分、皮肤生理功能指标[角质层含水量(Water content of stratum corneum,WCSC)、皮肤油脂(Skin sebum,SC)、经表皮水分流失(Transepidermal water loss,TEWL)]、复发情况、不良反应及美学效果满意度。结果:治疗4周后,联合组总有效率为88.68%,对照组为71.15%,差异有统计学意义(P<0.05)。治疗前两组患儿各项症状体征评分差异均无统计学意义(P>0.05);治疗4周后,两组患儿鳞屑、瘙痒、色素减退、皮损面积及皮损数量评分均较治疗前显著降低(P<0.05),且联合组各症状体征评分明显低于对照组(P<0.05);治疗前两组患儿皮肤生理功能指标差异均无统计学意义(P>0.05);治疗4周后,两组患儿WCSC和SC均显著升高(P<0.05),TEWL均显著降低(P<0.05),且联合组改善优于对照组(P<0.05);结束治疗随访4周,联合组患儿复发率(14.89%)低于对照组(27.03%),差异无统计学意义(P>0.05);治疗期间,两组患儿均未出现明显不良反应;联合组患儿美学效果总满意度(96.23%)显著高于对照组(82.69%)(P<0.05)。结论:0.03%他克莫司软膏联合多磺酸粘多糖乳膏治疗面部单纯糠疹疗效显著,可有效改善患儿皮损症状和皮肤生理功能,能有效预防复发,提高美学效果,且安全性好,值得临床推广应用。展开更多
基金supported by National Natural Science Foundation of China(41161079)
文摘Guiyang is a famous tourist city located in southwestern China. In this study, dust from eleven residential areas, seven city squares, and nine schools was collected to measure the heavy metal levels and evaluate its risk. At each sampling site, 4–5 sub-samples were taken as a bulk sample. All samples were air-dried, ground, passed through a 0.105 mm nylon sieve, digested with HNO3-HClO4 to determine the concentrations of Cd, Cu, Ni, Pb and Zn by ICP-MS, and digested with 1:1 aqua regia to determine As by AFS. The results show that the concentrations of As, Cd, Cu, Ni, Pb and Zn in dust of Guiyang City follow normal distribution with means of 16.1, 1.54, 138, 47.7, 129 and 479 mg/kg, respectively. Levels of As, Cd, Cu, Ni, Pb and Zn exceed the background level of soil in Guizhou Province by 33%, 96%, 100%, 78%, 96%, and 100%, respectively. Cd, Cu, Pb and Zn are heavily accumulated in dust of living areas with accumulation factors of 4.10, 5.12, 4.12 and 5.51, respectively. City square possesses the highest geometric means of As, Cd, Cu, Pb, and Zn. The risks of heavy metal exposure to teenagers are not obvious and in an order of As>Pb>Cu>Ni>Zn(Cd).
文摘针对带时间窗的时间依赖型同时取送货车辆路径问题(Time Dependent Vehicle Routing Problem with Simultaneous Pickup-Delivery and Time Windows,TDVRPSPDTW),本文建立以车辆固定成本、驾驶员成本、燃油消耗及碳排放成本之和为优化目标的数学模型;并在传统蚁群算法的基础上,利用节约启发式构造初始解初始化信息素,改进状态转移规则,引入局部搜索策略,提出一种带自适应大邻域搜索的混合蚁群算法(Ant Colony Optimization with Adaptive Large Neighborhood Search,ACO-ALNS)进行求解;最后,分别选取基准问题算例和改编生成TDVRPSPDTW算例进行实验。实验结果表明:本文提出的ACO-ALNS算法可有效解决TDVRPSPDTW的基准问题;相较于模拟退火算法和带局部搜索的蚁群算法,本文算法求解得到的总配送成本最优值平均分别改善7.56%和2.90%;另外,相比于仅考虑碳排放或配送时间的模型,本文所构建的模型综合多种因素,总配送成本平均分别降低4.38%和3.18%,可有效提高物流企业的经济效益。
文摘目的:观察探讨0.03%他克莫司软膏联合多磺酸粘多糖乳膏治疗面部单纯糠疹的美学效果。方法:选取2019年11月-2022年1月门诊收治的105例面部单纯糠疹患儿为观察对象,通过随机数字法随机分为联合组(n=53)和对照组(n=52),对照组给予多磺酸粘多糖乳膏治疗,联合组在对照组基础上加用0.03%他克莫司软膏治疗,比较两组治疗后的临床疗效、症状体征评分、皮肤生理功能指标[角质层含水量(Water content of stratum corneum,WCSC)、皮肤油脂(Skin sebum,SC)、经表皮水分流失(Transepidermal water loss,TEWL)]、复发情况、不良反应及美学效果满意度。结果:治疗4周后,联合组总有效率为88.68%,对照组为71.15%,差异有统计学意义(P<0.05)。治疗前两组患儿各项症状体征评分差异均无统计学意义(P>0.05);治疗4周后,两组患儿鳞屑、瘙痒、色素减退、皮损面积及皮损数量评分均较治疗前显著降低(P<0.05),且联合组各症状体征评分明显低于对照组(P<0.05);治疗前两组患儿皮肤生理功能指标差异均无统计学意义(P>0.05);治疗4周后,两组患儿WCSC和SC均显著升高(P<0.05),TEWL均显著降低(P<0.05),且联合组改善优于对照组(P<0.05);结束治疗随访4周,联合组患儿复发率(14.89%)低于对照组(27.03%),差异无统计学意义(P>0.05);治疗期间,两组患儿均未出现明显不良反应;联合组患儿美学效果总满意度(96.23%)显著高于对照组(82.69%)(P<0.05)。结论:0.03%他克莫司软膏联合多磺酸粘多糖乳膏治疗面部单纯糠疹疗效显著,可有效改善患儿皮损症状和皮肤生理功能,能有效预防复发,提高美学效果,且安全性好,值得临床推广应用。
