The single event transient effects of the operational amplifier LM124J and the optocoupler HCPL 5231 are investigated by a pulsed laser test facility. The relation of transient pulse shape to pulsed laser equivalent L...The single event transient effects of the operational amplifier LM124J and the optocoupler HCPL 5231 are investigated by a pulsed laser test facility. The relation of transient pulse shape to pulsed laser equivalent LET is tested,the sensitive areas of the SET effects are identified in voltage follower application mode of LM124J, and the mechanism is initially analyzed. The transient amplitude and duration of HCPL5231 at various equivalent LET are examined,and the SET cross-section is measured. The results of our test and heavy ion experimental data coincide closely,indicating that a pulsed laser test facility is a valid tool for single event effect evaluation.展开更多
A series of slow drain current recovery transients at different gate biases after a short-term stress are observed in an AIGaN/GaN HEMT. As the variation of the time constants of the transients is small, the working t...A series of slow drain current recovery transients at different gate biases after a short-term stress are observed in an AIGaN/GaN HEMT. As the variation of the time constants of the transients is small, the working trap is determined to be electronic. A numerical simulation verifies this conclusion and reproduces the measured transients. The electron traps at different spatial positions in the device-on the ungated surface of the AIGaN layer,in the AIGaN barrier, and in the GaN layer are considered;corresponding behaviors in the stress and the transients are discussed;and for the simulated transients, agreement with and deviation from the measured transients are explained. Based on this discussion, we suggest that the measured transients are caused by the combined effects of a deep surface trap and a bulk trap in the GaN layer.展开更多
AAV-PHP.eB is an artificial adeno-associated virus(AAV)that crosses the blood-brain barrier and targets neurons more efficiently than other AAVs when administered systematically.While AAV-PHP.eB has been used in vario...AAV-PHP.eB is an artificial adeno-associated virus(AAV)that crosses the blood-brain barrier and targets neurons more efficiently than other AAVs when administered systematically.While AAV-PHP.eB has been used in various disease models,its cellular tropism in cerebrovascular diseases remains unclear.In the present study,we aimed to elucidate the tropism of AAV-PHP.eB for different cell types in the brain in a mouse model of ischemic stroke and evaluate its effectiveness in mediating basic fibroblast growth factor(bFGF)gene therapy.Mice were injected intravenously with AAV-PHP.eB either 14 days prior to(pre-stroke)or 1 day following(post-stroke)transient middle cerebral artery occlusion.Notably,we observed a shift in tropism from neurons to endothelial cells with post-stroke administration of AAV-PHP.eB-mNeonGreen(mNG).This endothelial cell tropism correlated strongly with expression of the endothelial membrane receptor lymphocyte antigen 6 family member A(Ly6A).Furthermore,AAV-PHP.eB-mediated overexpression of bFGF markedly improved neurobehavioral outcomes and promoted long-term neurogenesis and angiogenesis post-ischemic stroke.Our findings underscore the significance of considering potential tropism shifts when utilizing AAV-PHP.eB-mediated gene therapy in neurological diseases and suggest a promising new strategy for bFGF gene therapy in stroke treatment.展开更多
Photosynthesis is a promising method for H_(2)O_(2)production,but its application in pure water is limited by slow oxidation kinetics and rapid photocarrier recombination of photocatalysts.Herein,a novel defective car...Photosynthesis is a promising method for H_(2)O_(2)production,but its application in pure water is limited by slow oxidation kinetics and rapid photocarrier recombination of photocatalysts.Herein,a novel defective carbon nitride photocatalyst(D-C3-xN4)containing the C vacancies and the frustrated Lewis pairs(B and N of cyano group)is designed for H_(2)O_(2)photosynthesis,and the role of C vacancies on the electron transfer mechanism during photocatalysis is systematically investigated.The D-C_(3-x)N_(4) exhibits a H_(2)O_(2)production rate of 140.1μmol·g^(-1)·h^(-1) in pure water,which is 87.6 times that of C_(3)N_(4).Such superior performance for H_(2)O_(2)photosynthesis is found to arise from the C vacancies and frustrated Lewis pairs(FLPs).The C vacancies have strong electron-trapping ability,which greatly enhances the separation of photocarriers.The C vacancies can also effectively reduce O_(2)to*OOH via a proton-coupled process,which significantly accelerates the O_(2)reduction kinetics.Meanwhile,the FLPs show an outstanding catalytic activity for H_(2)O oxidation.This study not only provides a new structure for highly active photocatalysts,but also deepens the understanding of the electron transfer mechanism of photocatalysts with trapped sites.展开更多
Numerous pathological states of the nervous system involve alterations in neuronal excitability and synaptic dysfunction,which depend on the function of ion channels.Due to their critical involvement in health and dis...Numerous pathological states of the nervous system involve alterations in neuronal excitability and synaptic dysfunction,which depend on the function of ion channels.Due to their critical involvement in health and disease,the search for new compounds that modulate these proteins is still relevant.Traditional medicine has long been a rich source of neuroactive compounds.For example,the indigenous Mapuche people have used the leaves and bark of the Drimys winteri tree for centuries to treat various diseases.Consequently,several studies have investigated the biological effects of compounds in Drimys winteri,highlighting sesquiterpenes such asα-humulene,drimenin,polygodial,andα-,β-,γ-eudesmol.However,there is currently no literature review focusing on the ability of these sesquiterpenes to modulate ion channels.This review summarizes the current knowledge about neuroactive compounds found in Drimys winteri,with special emphasis on their direct actions on neuronal ion channels.Several Drimys winteri sesquiterpenes modulate a diverse array of neuronal ion channels,including transient receptor potential channels,gamma-aminobutyric acid A receptors,nicotinic acetylcholine receptors,and voltage-dependent Ca^(2+)and Na^(+)channels.Interestingly,the modulation of these molecular targets by Drimys winteri sesquiterpenes correlates with their therapeutic actions.The promiscuous pharmacological profile of Drimys winteri sesquiterpenes suggests they modulate multiple protein targets in vivo,making them potentially useful for treating complex,multifactorial diseases.Further studies at the molecular level may aid in developing multitargeted drugs with enhanced therapeutic effects.展开更多
目的:构建并验证基于磁共振增强平衡期(T1-delay MR)的机器学习模型(MR模型)无创评估肝脏纤维化分级,并与超声瞬时弹性成像肝硬度值(LSM)进行联合/对比,探讨MR模型对于LSM的附加价值。方法:回顾性单中心研究纳入了659例肝纤维化患者,随...目的:构建并验证基于磁共振增强平衡期(T1-delay MR)的机器学习模型(MR模型)无创评估肝脏纤维化分级,并与超声瞬时弹性成像肝硬度值(LSM)进行联合/对比,探讨MR模型对于LSM的附加价值。方法:回顾性单中心研究纳入了659例肝纤维化患者,随机拆分为训练集和测试集。经图像预处理后,通过层次化建模的方法筛选特征。通过将特征按层次结构划分子类并分别考察子类建模在验证集上的表现,筛选出重要的特征,建立MR模型分别对显著性(F≥2)和进展期肝纤维化(F≥3)进行分类,并与LSM联合构建MR-LSM模型。使用受试者工作特征曲线、瀑布图、决策曲线分析评估模型的性能。结果:分类F≥2时,MR-LSM在测试集中优于MR模型(0.824 vs 0.791,P=0.003)和LSM(0.694,P=0.005)。分类F≥3时,MR-LSM AUC高于MR模型(0.855 vs 0.819,P=0.004),且优于LSM(0.731,P<0.001)。结论:MR-LSM模型在肝纤维化分级中诊断效能优于单独的MR模型和LSM,MR模型对于LSM具有附加价值。展开更多
The influence of enlarged section parameters on pressure transients of high-speed train passing through a tunnel was investigated by numerical simulation.The calculation results obtained by the structured and unstruct...The influence of enlarged section parameters on pressure transients of high-speed train passing through a tunnel was investigated by numerical simulation.The calculation results obtained by the structured and unstructured grid and the experimental results of smooth wall tunnel were verified.Numerical simulation studies were conducted on three tunnel enlarged section parameters,the enlarged section distribution along circumferential direction,the enlarged section area and the enlarged section distribution along tunnel length direction.The calculation results show that the influence of the different enlarged section distributions along tunnel circumferential direction on pressure transients in the tunnel is basically consistent.There is an optimal enlarged section area for the minimum value of the pressure variation amplitude and the average pressure variation in the tunnel.The law of the pressure variation amplitude and the average pressure variation of the enlarged section distribution along tunnel length direction are obtained.展开更多
文摘The single event transient effects of the operational amplifier LM124J and the optocoupler HCPL 5231 are investigated by a pulsed laser test facility. The relation of transient pulse shape to pulsed laser equivalent LET is tested,the sensitive areas of the SET effects are identified in voltage follower application mode of LM124J, and the mechanism is initially analyzed. The transient amplitude and duration of HCPL5231 at various equivalent LET are examined,and the SET cross-section is measured. The results of our test and heavy ion experimental data coincide closely,indicating that a pulsed laser test facility is a valid tool for single event effect evaluation.
文摘A series of slow drain current recovery transients at different gate biases after a short-term stress are observed in an AIGaN/GaN HEMT. As the variation of the time constants of the transients is small, the working trap is determined to be electronic. A numerical simulation verifies this conclusion and reproduces the measured transients. The electron traps at different spatial positions in the device-on the ungated surface of the AIGaN layer,in the AIGaN barrier, and in the GaN layer are considered;corresponding behaviors in the stress and the transients are discussed;and for the simulated transients, agreement with and deviation from the measured transients are explained. Based on this discussion, we suggest that the measured transients are caused by the combined effects of a deep surface trap and a bulk trap in the GaN layer.
基金supported by the National Natural Science Foundation of China,Nos.81870921(to YW),81974179(to ZZ),82271320(to ZZ),82071284(to YT)National Key R&D Program of China,No.2022YFA1603600(to ZZ),2019YFA0112000(to YT)+1 种基金Scientific Research and Innovation Program of Shanghai Education Commission,No.2019-01-07-00-02-E00064(to GYY)Scientific and Technological Innovation Act Program of Shanghai Science and Technology Commission,No.20JC1411900(to GYY).
文摘AAV-PHP.eB is an artificial adeno-associated virus(AAV)that crosses the blood-brain barrier and targets neurons more efficiently than other AAVs when administered systematically.While AAV-PHP.eB has been used in various disease models,its cellular tropism in cerebrovascular diseases remains unclear.In the present study,we aimed to elucidate the tropism of AAV-PHP.eB for different cell types in the brain in a mouse model of ischemic stroke and evaluate its effectiveness in mediating basic fibroblast growth factor(bFGF)gene therapy.Mice were injected intravenously with AAV-PHP.eB either 14 days prior to(pre-stroke)or 1 day following(post-stroke)transient middle cerebral artery occlusion.Notably,we observed a shift in tropism from neurons to endothelial cells with post-stroke administration of AAV-PHP.eB-mNeonGreen(mNG).This endothelial cell tropism correlated strongly with expression of the endothelial membrane receptor lymphocyte antigen 6 family member A(Ly6A).Furthermore,AAV-PHP.eB-mediated overexpression of bFGF markedly improved neurobehavioral outcomes and promoted long-term neurogenesis and angiogenesis post-ischemic stroke.Our findings underscore the significance of considering potential tropism shifts when utilizing AAV-PHP.eB-mediated gene therapy in neurological diseases and suggest a promising new strategy for bFGF gene therapy in stroke treatment.
基金supported by the Shaanxi Sanqin Scholars Innovation Team,the Science and Technology Project of Yan’an City(No.2023-CYL-193)the Key Science Research Plan of Department of Education in Shaanxi Province(No.23JS070)the Science Research Training Project(No.CLXZ2207).
文摘Photosynthesis is a promising method for H_(2)O_(2)production,but its application in pure water is limited by slow oxidation kinetics and rapid photocarrier recombination of photocatalysts.Herein,a novel defective carbon nitride photocatalyst(D-C3-xN4)containing the C vacancies and the frustrated Lewis pairs(B and N of cyano group)is designed for H_(2)O_(2)photosynthesis,and the role of C vacancies on the electron transfer mechanism during photocatalysis is systematically investigated.The D-C_(3-x)N_(4) exhibits a H_(2)O_(2)production rate of 140.1μmol·g^(-1)·h^(-1) in pure water,which is 87.6 times that of C_(3)N_(4).Such superior performance for H_(2)O_(2)photosynthesis is found to arise from the C vacancies and frustrated Lewis pairs(FLPs).The C vacancies have strong electron-trapping ability,which greatly enhances the separation of photocarriers.The C vacancies can also effectively reduce O_(2)to*OOH via a proton-coupled process,which significantly accelerates the O_(2)reduction kinetics.Meanwhile,the FLPs show an outstanding catalytic activity for H_(2)O oxidation.This study not only provides a new structure for highly active photocatalysts,but also deepens the understanding of the electron transfer mechanism of photocatalysts with trapped sites.
基金supported by ANID-FONDECYT 1200908(to JF),ANID-FONDECYT 1211082 and 1250856(to GEY)by the Millennium Nucleus for the Study of Pain NCN19_038(Mi Nu SPain)(to GEY)funded by the ANID scholarship 21201176。
文摘Numerous pathological states of the nervous system involve alterations in neuronal excitability and synaptic dysfunction,which depend on the function of ion channels.Due to their critical involvement in health and disease,the search for new compounds that modulate these proteins is still relevant.Traditional medicine has long been a rich source of neuroactive compounds.For example,the indigenous Mapuche people have used the leaves and bark of the Drimys winteri tree for centuries to treat various diseases.Consequently,several studies have investigated the biological effects of compounds in Drimys winteri,highlighting sesquiterpenes such asα-humulene,drimenin,polygodial,andα-,β-,γ-eudesmol.However,there is currently no literature review focusing on the ability of these sesquiterpenes to modulate ion channels.This review summarizes the current knowledge about neuroactive compounds found in Drimys winteri,with special emphasis on their direct actions on neuronal ion channels.Several Drimys winteri sesquiterpenes modulate a diverse array of neuronal ion channels,including transient receptor potential channels,gamma-aminobutyric acid A receptors,nicotinic acetylcholine receptors,and voltage-dependent Ca^(2+)and Na^(+)channels.Interestingly,the modulation of these molecular targets by Drimys winteri sesquiterpenes correlates with their therapeutic actions.The promiscuous pharmacological profile of Drimys winteri sesquiterpenes suggests they modulate multiple protein targets in vivo,making them potentially useful for treating complex,multifactorial diseases.Further studies at the molecular level may aid in developing multitargeted drugs with enhanced therapeutic effects.
文摘目的:构建并验证基于磁共振增强平衡期(T1-delay MR)的机器学习模型(MR模型)无创评估肝脏纤维化分级,并与超声瞬时弹性成像肝硬度值(LSM)进行联合/对比,探讨MR模型对于LSM的附加价值。方法:回顾性单中心研究纳入了659例肝纤维化患者,随机拆分为训练集和测试集。经图像预处理后,通过层次化建模的方法筛选特征。通过将特征按层次结构划分子类并分别考察子类建模在验证集上的表现,筛选出重要的特征,建立MR模型分别对显著性(F≥2)和进展期肝纤维化(F≥3)进行分类,并与LSM联合构建MR-LSM模型。使用受试者工作特征曲线、瀑布图、决策曲线分析评估模型的性能。结果:分类F≥2时,MR-LSM在测试集中优于MR模型(0.824 vs 0.791,P=0.003)和LSM(0.694,P=0.005)。分类F≥3时,MR-LSM AUC高于MR模型(0.855 vs 0.819,P=0.004),且优于LSM(0.731,P<0.001)。结论:MR-LSM模型在肝纤维化分级中诊断效能优于单独的MR模型和LSM,MR模型对于LSM具有附加价值。
基金Project (2016YFB1200602-11) supported by National Key R&D Plan of China
文摘The influence of enlarged section parameters on pressure transients of high-speed train passing through a tunnel was investigated by numerical simulation.The calculation results obtained by the structured and unstructured grid and the experimental results of smooth wall tunnel were verified.Numerical simulation studies were conducted on three tunnel enlarged section parameters,the enlarged section distribution along circumferential direction,the enlarged section area and the enlarged section distribution along tunnel length direction.The calculation results show that the influence of the different enlarged section distributions along tunnel circumferential direction on pressure transients in the tunnel is basically consistent.There is an optimal enlarged section area for the minimum value of the pressure variation amplitude and the average pressure variation in the tunnel.The law of the pressure variation amplitude and the average pressure variation of the enlarged section distribution along tunnel length direction are obtained.
