The development of an efficient artificial H_(2)O_(2)photosynthesis system is a challenging work using H_(2)O and O_(2)as starting materials.Herein,3D In2.77S_(4)nanoflower precursor was in-situ deposited on K^(+)-dop...The development of an efficient artificial H_(2)O_(2)photosynthesis system is a challenging work using H_(2)O and O_(2)as starting materials.Herein,3D In2.77S_(4)nanoflower precursor was in-situ deposited on K^(+)-doped g-C_(3)N_(4)(KCN)nanosheets using a solvothermal method,then In2.77S_(4)/KCN(IS/KCN)het-erojunction with an intimate interface was obtained after a calcination process.The investigation shows that the photocatalytic H_(2)O_(2)production rate of 50IS/KCN can reach up to 1.36 mmol g^(-1)h^(-1)without any sacrificial reagents under visible light irradiation,which is 9.2 times and 4.1 times higher than that of KCN and In2.77S_(4),respectively.The enhanced activity of the above composite can be mainly attributed to the S-scheme charge transfer route between KCN and In2.77S_(4)according to density functional theory calculations,electron paramagnetic resonance and free radical capture tests,leading to an expanded light response range and rapid charge separation at their interface,as well as preserving the active electrons and holes for H_(2)O_(2)production.Besides,the unique 3D nanostructure and surface hydrophobicity of IS/KCN facilitate the diffusion and transportation of O_(2)around the active centers,the energy barriers of O_(2)protonation and H_(2)O_(2)desorption steps are ef-fectively reduced over the composite.In addition,this system also exhibits excellent light harvesting ability and stability.This work provides a potential strategy to explore a sustainable H_(2)O_(2)photo-synthesis pathway through the design of heterojunctions with intimate interfaces and desired reac-tion thermodynamics and kinetics.展开更多
We applied a spatial high-order finite-difference-time-domain (HO-FDTD) scheme to solve 2D Maxwell’s equations in order to develop a fluid model employed to study the production of terahertz radiation by the filament...We applied a spatial high-order finite-difference-time-domain (HO-FDTD) scheme to solve 2D Maxwell’s equations in order to develop a fluid model employed to study the production of terahertz radiation by the filamentation of two femtosecond lasers in air plasma. We examined the performance of the applied scheme, in this context, we implemented the developed model to study selected phenomena in terahertz radiation production, such as the excitation energy and conversion efficiency of the produced THz radiation, in addition to the influence of the pulse chirping on properties of the produced radiation. The obtained numerical results have clarified that the applied HO-FDTD scheme is precisely accurate to solve Maxwell’s equations and sufficiently valid to study the production of terahertz radiation by the filamentation of two femtosecond lasers in air plasma.展开更多
Rainfall and temperature are the important variables that are often used to trace climate variability and change. A Perception study and analysis of climatic data were conducted to assess the changes in rainfall and t...Rainfall and temperature are the important variables that are often used to trace climate variability and change. A Perception study and analysis of climatic data were conducted to assess the changes in rainfall and temperature and their impact on crop production in Moyamba district, Sierra Leone. For the perception study, 400 farmers were randomly selected from Farmer-Based Organizations (FBOs) in 4 chiefdoms and 30 Agricultural Extension Workers (AWEs) in the Moyamba district were purposely selected as respondents. Descriptive statistics and Kendall’s test of concordance was used to analyze the data collected from the farmers and AEWs. Data for the analysis of variability and trends of rainfall and temperature from 1991 to 2020 were obtained from the Sierra Leone Meteorological Agency and Njala University and grouped into monthly, seasonal and annual time series. Regression analyses were used to determine the statistical values and trend lines for the seasonal and annual time series data. The Mann-Kendall test and Sen’s Slope Estimator were used to analyze the significance and magnitude of the trends respectively. The results of both studies show evidence of climate change in the Moyamba district. A substantial number of farmers and AEWs perceived a decrease in the annual rainfall amount, length of the rainy season, a late start and end of the rainy season, an increase in the temperature during the day and night, and a shortened harmattan period over the last 30 years. Analysis of the meteorological data shows evidence of variability in the seasonal and annual distribution of rainfall and temperature, a decreasing and non-significant trend in the rainy season and annual rainfall and an increasing and significant trend in seasonal and annual temperature from 1991 to 2020. However, the observed changes in rainfall and temperature by the farmers and AEWs partially agree with the results of the analyzed meteorological data. The majority of the farmers perceived that;adverse weather conditions have negatively affected crop production in the district. Droughts, high temperatures, and irregular rainfall are the three major adverse weather events that farmers perceived to have contributed to a substantial loss in the yields of the major crops cultivated in the district. In response to the negative effects of adverse weather events, a substantial number of farmers take no action due to their lack of knowledge, technical or financial capacity to implement climate-sensitive agricultural (CSA) practices. Even though few farmers are practicing some CSA practices on their farms, there is an urgent need to build the capacity of farmers and AEWs to adapt to and mitigate the negative impacts of climate change. The most priority support needed by farmers is the provision of climate-resilient crop varieties whilst the AEWs need training on CSA practices.展开更多
目的评估鞘内合成相关标志物在轻度认知功能障碍(MCI)、阿尔茨海默病(AD)和其他类型痴呆患者中的应用价值。方法回顾性收集首都医科大学附属北京天坛医院2019年6月至2023年7月577例临床确诊为MCI(MCI组,178例)、AD(AD组,131例)、其他类...目的评估鞘内合成相关标志物在轻度认知功能障碍(MCI)、阿尔茨海默病(AD)和其他类型痴呆患者中的应用价值。方法回顾性收集首都医科大学附属北京天坛医院2019年6月至2023年7月577例临床确诊为MCI(MCI组,178例)、AD(AD组,131例)、其他类型痴呆(其他类型组,268例)患者的临床资料,查询各组寡克隆区带电泳(OCB)和24 h鞘内蛋白合成率(ISR),比较各组不同指标的差异,评估相关指标在不同疾病中的鉴别诊断价值。结果与AD组及其他类型组比较,AD组患者女性占比更高、年龄多分布在>50~70岁,脂代谢异常的发生率更高,差异有统计学意义(P<0.05)。不同疾病组血清IgG寡克隆区带[OB(S)]、脑脊液白蛋白、血清白蛋白和脑脊液IgG比较,差异均有统计学意义(P<0.05)。脑脊液特异IgG寡克隆区带[SOB(CSF)]阳性患者IgG指数和ISR高于阴性和弱阳性患者,差异均有统计学意义(P<0.001)。IgG指数和ISR呈正相关(r=0.878,P<0.001)。结论IgG指数、SOB(CSF)和24 h ISR等鞘内合成相关标志物在认知功能障碍及各类痴呆性疾病的诊断中具有协同作用,可共同用于疾病的诊断。展开更多
文摘The development of an efficient artificial H_(2)O_(2)photosynthesis system is a challenging work using H_(2)O and O_(2)as starting materials.Herein,3D In2.77S_(4)nanoflower precursor was in-situ deposited on K^(+)-doped g-C_(3)N_(4)(KCN)nanosheets using a solvothermal method,then In2.77S_(4)/KCN(IS/KCN)het-erojunction with an intimate interface was obtained after a calcination process.The investigation shows that the photocatalytic H_(2)O_(2)production rate of 50IS/KCN can reach up to 1.36 mmol g^(-1)h^(-1)without any sacrificial reagents under visible light irradiation,which is 9.2 times and 4.1 times higher than that of KCN and In2.77S_(4),respectively.The enhanced activity of the above composite can be mainly attributed to the S-scheme charge transfer route between KCN and In2.77S_(4)according to density functional theory calculations,electron paramagnetic resonance and free radical capture tests,leading to an expanded light response range and rapid charge separation at their interface,as well as preserving the active electrons and holes for H_(2)O_(2)production.Besides,the unique 3D nanostructure and surface hydrophobicity of IS/KCN facilitate the diffusion and transportation of O_(2)around the active centers,the energy barriers of O_(2)protonation and H_(2)O_(2)desorption steps are ef-fectively reduced over the composite.In addition,this system also exhibits excellent light harvesting ability and stability.This work provides a potential strategy to explore a sustainable H_(2)O_(2)photo-synthesis pathway through the design of heterojunctions with intimate interfaces and desired reac-tion thermodynamics and kinetics.
文摘We applied a spatial high-order finite-difference-time-domain (HO-FDTD) scheme to solve 2D Maxwell’s equations in order to develop a fluid model employed to study the production of terahertz radiation by the filamentation of two femtosecond lasers in air plasma. We examined the performance of the applied scheme, in this context, we implemented the developed model to study selected phenomena in terahertz radiation production, such as the excitation energy and conversion efficiency of the produced THz radiation, in addition to the influence of the pulse chirping on properties of the produced radiation. The obtained numerical results have clarified that the applied HO-FDTD scheme is precisely accurate to solve Maxwell’s equations and sufficiently valid to study the production of terahertz radiation by the filamentation of two femtosecond lasers in air plasma.
文摘Rainfall and temperature are the important variables that are often used to trace climate variability and change. A Perception study and analysis of climatic data were conducted to assess the changes in rainfall and temperature and their impact on crop production in Moyamba district, Sierra Leone. For the perception study, 400 farmers were randomly selected from Farmer-Based Organizations (FBOs) in 4 chiefdoms and 30 Agricultural Extension Workers (AWEs) in the Moyamba district were purposely selected as respondents. Descriptive statistics and Kendall’s test of concordance was used to analyze the data collected from the farmers and AEWs. Data for the analysis of variability and trends of rainfall and temperature from 1991 to 2020 were obtained from the Sierra Leone Meteorological Agency and Njala University and grouped into monthly, seasonal and annual time series. Regression analyses were used to determine the statistical values and trend lines for the seasonal and annual time series data. The Mann-Kendall test and Sen’s Slope Estimator were used to analyze the significance and magnitude of the trends respectively. The results of both studies show evidence of climate change in the Moyamba district. A substantial number of farmers and AEWs perceived a decrease in the annual rainfall amount, length of the rainy season, a late start and end of the rainy season, an increase in the temperature during the day and night, and a shortened harmattan period over the last 30 years. Analysis of the meteorological data shows evidence of variability in the seasonal and annual distribution of rainfall and temperature, a decreasing and non-significant trend in the rainy season and annual rainfall and an increasing and significant trend in seasonal and annual temperature from 1991 to 2020. However, the observed changes in rainfall and temperature by the farmers and AEWs partially agree with the results of the analyzed meteorological data. The majority of the farmers perceived that;adverse weather conditions have negatively affected crop production in the district. Droughts, high temperatures, and irregular rainfall are the three major adverse weather events that farmers perceived to have contributed to a substantial loss in the yields of the major crops cultivated in the district. In response to the negative effects of adverse weather events, a substantial number of farmers take no action due to their lack of knowledge, technical or financial capacity to implement climate-sensitive agricultural (CSA) practices. Even though few farmers are practicing some CSA practices on their farms, there is an urgent need to build the capacity of farmers and AEWs to adapt to and mitigate the negative impacts of climate change. The most priority support needed by farmers is the provision of climate-resilient crop varieties whilst the AEWs need training on CSA practices.
文摘目的评估鞘内合成相关标志物在轻度认知功能障碍(MCI)、阿尔茨海默病(AD)和其他类型痴呆患者中的应用价值。方法回顾性收集首都医科大学附属北京天坛医院2019年6月至2023年7月577例临床确诊为MCI(MCI组,178例)、AD(AD组,131例)、其他类型痴呆(其他类型组,268例)患者的临床资料,查询各组寡克隆区带电泳(OCB)和24 h鞘内蛋白合成率(ISR),比较各组不同指标的差异,评估相关指标在不同疾病中的鉴别诊断价值。结果与AD组及其他类型组比较,AD组患者女性占比更高、年龄多分布在>50~70岁,脂代谢异常的发生率更高,差异有统计学意义(P<0.05)。不同疾病组血清IgG寡克隆区带[OB(S)]、脑脊液白蛋白、血清白蛋白和脑脊液IgG比较,差异均有统计学意义(P<0.05)。脑脊液特异IgG寡克隆区带[SOB(CSF)]阳性患者IgG指数和ISR高于阴性和弱阳性患者,差异均有统计学意义(P<0.001)。IgG指数和ISR呈正相关(r=0.878,P<0.001)。结论IgG指数、SOB(CSF)和24 h ISR等鞘内合成相关标志物在认知功能障碍及各类痴呆性疾病的诊断中具有协同作用,可共同用于疾病的诊断。
