Since the outbreak of the Ukraine crisis,the EU has been under unprecedented geopolitical pressure and has encountered difficulties in both economic and diplomatic fields,with its external relations undergoing multipl...Since the outbreak of the Ukraine crisis,the EU has been under unprecedented geopolitical pressure and has encountered difficulties in both economic and diplomatic fields,with its external relations undergoing multiple changes.To address the new challenges and uncertainties that have emerged,the EU,on the one hand,is actively promoting strategic autonomy,striving to enhance its independent capabilities in areas such as defense and energy security.展开更多
目的:探讨核因子E2相关因子2(Nrf2)对小鼠神经干细胞(NSCs)增殖和分化能力的影响。方法:分离新生小鼠海马组织,培养NSCs,采用电穿孔法将Nrf2 siRNA序列转染至NSCs,分别用real time RT-PCR和Western Blot检测敲减效率;运用BrdU掺入实验、...目的:探讨核因子E2相关因子2(Nrf2)对小鼠神经干细胞(NSCs)增殖和分化能力的影响。方法:分离新生小鼠海马组织,培养NSCs,采用电穿孔法将Nrf2 siRNA序列转染至NSCs,分别用real time RT-PCR和Western Blot检测敲减效率;运用BrdU掺入实验、Tuj1免疫荧光染色和CCK-8法检测Nrf2靶向siRNA对NSCs的增殖、分化能力和细胞活力的影响。通过脑立体定位技术,在成年小鼠海马部位注射Nrf2抑制剂Brusatol,应用Western Blot检测Nrf2的蛋白表达水平;通过Ki67、DCX免疫荧光染色检测下调Nrf2对海马神经发生的影响。利用活性氧簇(ROS)水平测定法和real time RT-PCR分别检测活性氧水平和氧化应激相关通路超氧化物歧化酶(SOD1和SOD2)的表达。结果:Nrf2的siRNA序列转染至NSCs,real time RT-PCR结果显示siRNA的敲减效率为(54.56±7.05)%(P<0.01),Western Blot结果显示siRNA的敲减效率为(39.50±7.90)%(P<0.01);与NC-siRNA组相比,Nrf2-siRNA组的BrdU阳性率、细胞活力均下降(P<0.01),1%胎牛血清诱导分化后,Nrf2-siRNA组Tuj1阳性率下降(P<0.01);同时Nrf2-siRNA组SOD1和SOD2的mRNA水平均较NC-siRNA组下降(P<0.05),而ROS水平较NC-siRNA组升高(P<0.05)。脑内注射Nrf2抑制剂Brusatol后,与Control组相比,Brusatol组的海马组织Nrf2蛋白表达水平降低(P<0.01);Brusatol组Ki67阳性、DCX阳性细胞数量均减少(P<0.05和P<0.01);此外Brusatol组SOD1 mRNA和SOD2水平均较Control组下降(P<0.05),而ROS水平较Control组升高(P<0.05)。结论:Nrf2基因敲减导致NSCs氧化应激水平升高,进而抑制了NSCs增殖和分化能力。展开更多
The aerodynamic layout of the Canard Rotor/Wing(CRW) aircraft in helicopter flight mode differs significantly from that of conventional helicopters. In order to study the flight dynamics characteristics of CRW aircraf...The aerodynamic layout of the Canard Rotor/Wing(CRW) aircraft in helicopter flight mode differs significantly from that of conventional helicopters. In order to study the flight dynamics characteristics of CRW aircraft in helicopter mode, first, the aerodynamic model of the main rotor system is established based on the blade element theory and wind tunnel test results. The aerodynamic forces and moments of the canard wing, horizontal tail, vertical tail and fuselage are obtained via theoretical analysis and empirical formula. The flight dynamics model of the CRW aircraft in helicopter mode is developed and validated by flight test data. Next, a method of model trimming using an optimization algorithm is proposed. The flight dynamics characteristics of the CRW are investigated by the method of linearized small perturbations via Simulink. The trim results are consistent with the conventional helicopter characteristics, and the results show that with increasing forward flight speed, the canard wing and horizontal tail can provide considerable lift,which reflects the unique characteristics of the CRW aircraft. Finally, mode analysis is implemented for the linearized CRW in helicopter mode. The results demonstrate that the stability of majority modes increases with increasing flight speed. However, one mode that diverges monotonously,and the reason is that the CRW helicopter mode has a large vertical tail compared to the conventional helicopter. The results of the dynamic analysis provide optimization guidance and reference for the overall design of the CRW aircraft in helicopter mode, and the model developed can be used for control system design.展开更多
The interest in curtailing environmental pollution issues through physical separation processes has inspired an extensive search for novel nanoporous materials with exceptional adsorption capabilities.Covalent triazin...The interest in curtailing environmental pollution issues through physical separation processes has inspired an extensive search for novel nanoporous materials with exceptional adsorption capabilities.Covalent triazine frameworks(CTFs),emerged as a class of crystalline covalent organic frameworks(COFs),have been widely examined for various separation applications,owing to their large porosity,high stability,and rich nitrogen(N)doping.The development of CTFs for efficient adsorption of mercury(Ⅱ)(Hg^(2+))is of great importance for the field,whereas it is rarely attempted,on account of limited synthetic strategies and unknown structural-property relations of conventional CTFs derived from ionothermal approaches.Herein,we report rational synthesis of a crystalline CTF with methylthio pendant arms for efficient removal of Hg^(2+)with an exceptional capacity of 751 mg·g^(-1),ranking at the top among previously-reported adsorbents.This work may open up new possibility in the synthesis of COFs for various separations.展开更多
文摘Since the outbreak of the Ukraine crisis,the EU has been under unprecedented geopolitical pressure and has encountered difficulties in both economic and diplomatic fields,with its external relations undergoing multiple changes.To address the new challenges and uncertainties that have emerged,the EU,on the one hand,is actively promoting strategic autonomy,striving to enhance its independent capabilities in areas such as defense and energy security.
文摘目的:探讨核因子E2相关因子2(Nrf2)对小鼠神经干细胞(NSCs)增殖和分化能力的影响。方法:分离新生小鼠海马组织,培养NSCs,采用电穿孔法将Nrf2 siRNA序列转染至NSCs,分别用real time RT-PCR和Western Blot检测敲减效率;运用BrdU掺入实验、Tuj1免疫荧光染色和CCK-8法检测Nrf2靶向siRNA对NSCs的增殖、分化能力和细胞活力的影响。通过脑立体定位技术,在成年小鼠海马部位注射Nrf2抑制剂Brusatol,应用Western Blot检测Nrf2的蛋白表达水平;通过Ki67、DCX免疫荧光染色检测下调Nrf2对海马神经发生的影响。利用活性氧簇(ROS)水平测定法和real time RT-PCR分别检测活性氧水平和氧化应激相关通路超氧化物歧化酶(SOD1和SOD2)的表达。结果:Nrf2的siRNA序列转染至NSCs,real time RT-PCR结果显示siRNA的敲减效率为(54.56±7.05)%(P<0.01),Western Blot结果显示siRNA的敲减效率为(39.50±7.90)%(P<0.01);与NC-siRNA组相比,Nrf2-siRNA组的BrdU阳性率、细胞活力均下降(P<0.01),1%胎牛血清诱导分化后,Nrf2-siRNA组Tuj1阳性率下降(P<0.01);同时Nrf2-siRNA组SOD1和SOD2的mRNA水平均较NC-siRNA组下降(P<0.05),而ROS水平较NC-siRNA组升高(P<0.05)。脑内注射Nrf2抑制剂Brusatol后,与Control组相比,Brusatol组的海马组织Nrf2蛋白表达水平降低(P<0.01);Brusatol组Ki67阳性、DCX阳性细胞数量均减少(P<0.05和P<0.01);此外Brusatol组SOD1 mRNA和SOD2水平均较Control组下降(P<0.05),而ROS水平较Control组升高(P<0.05)。结论:Nrf2基因敲减导致NSCs氧化应激水平升高,进而抑制了NSCs增殖和分化能力。
文摘The aerodynamic layout of the Canard Rotor/Wing(CRW) aircraft in helicopter flight mode differs significantly from that of conventional helicopters. In order to study the flight dynamics characteristics of CRW aircraft in helicopter mode, first, the aerodynamic model of the main rotor system is established based on the blade element theory and wind tunnel test results. The aerodynamic forces and moments of the canard wing, horizontal tail, vertical tail and fuselage are obtained via theoretical analysis and empirical formula. The flight dynamics model of the CRW aircraft in helicopter mode is developed and validated by flight test data. Next, a method of model trimming using an optimization algorithm is proposed. The flight dynamics characteristics of the CRW are investigated by the method of linearized small perturbations via Simulink. The trim results are consistent with the conventional helicopter characteristics, and the results show that with increasing forward flight speed, the canard wing and horizontal tail can provide considerable lift,which reflects the unique characteristics of the CRW aircraft. Finally, mode analysis is implemented for the linearized CRW in helicopter mode. The results demonstrate that the stability of majority modes increases with increasing flight speed. However, one mode that diverges monotonously,and the reason is that the CRW helicopter mode has a large vertical tail compared to the conventional helicopter. The results of the dynamic analysis provide optimization guidance and reference for the overall design of the CRW aircraft in helicopter mode, and the model developed can be used for control system design.
基金The National Natural Science Foundation of China(22078349,22005319,52170109)Self-deployment Program from Lanzhou Institute of Chemical Physics(E30159SQ).
文摘The interest in curtailing environmental pollution issues through physical separation processes has inspired an extensive search for novel nanoporous materials with exceptional adsorption capabilities.Covalent triazine frameworks(CTFs),emerged as a class of crystalline covalent organic frameworks(COFs),have been widely examined for various separation applications,owing to their large porosity,high stability,and rich nitrogen(N)doping.The development of CTFs for efficient adsorption of mercury(Ⅱ)(Hg^(2+))is of great importance for the field,whereas it is rarely attempted,on account of limited synthetic strategies and unknown structural-property relations of conventional CTFs derived from ionothermal approaches.Herein,we report rational synthesis of a crystalline CTF with methylthio pendant arms for efficient removal of Hg^(2+)with an exceptional capacity of 751 mg·g^(-1),ranking at the top among previously-reported adsorbents.This work may open up new possibility in the synthesis of COFs for various separations.
