Although antipsychotics that act via monoaminergic neurotransmitter modulation have considera ble therapeutic effect,they cannot completely relieve clinical symptoms in patients suffering from psychiatric disorde rs.T...Although antipsychotics that act via monoaminergic neurotransmitter modulation have considera ble therapeutic effect,they cannot completely relieve clinical symptoms in patients suffering from psychiatric disorde rs.This may be attributed to the limited range of neurotransmitters that are regulated by psychotropic drugs.Recent findings indicate the need for investigation of psychotropic medications that target less-studied neurotransmitte rs.Among these candidate neurotransmitters,lactate is developing from being a waste metabolite to a glial-neuronal signaling molecule in recent years.Previous studies have suggested that cerebral lactate levels change considerably in numerous psychiatric illnesses;animal experiments have also shown that the supply of exogenous la ctate exerts an antidepressant effect.In this review,we have described how medications targeting newer neurotransmitte rs offer promise in psychiatric diseases;we have also summarized the advances in the use of lactate(and its corresponding signaling pathways)as a signaling molecule.In addition,we have described the alterations in brain lactate levels in depression,anxiety,bipolar disorder,and schizophrenia and have indicated the challenges that need to be overcome before brain lactate can be used as a therapeutic target in psychopharmacology.展开更多
The plasmapause locations determined from the Chang'e-3(CE-3) Extreme Ultraviolet Camera(EUVC) images and the auroral boundaries determined from the Defense Meteorological Satellite Program(DMSP) Special Sensor Ul...The plasmapause locations determined from the Chang'e-3(CE-3) Extreme Ultraviolet Camera(EUVC) images and the auroral boundaries determined from the Defense Meteorological Satellite Program(DMSP) Special Sensor Ultraviolet Spectrographic Imager(SSUSI) images are used to investigate the plasmaspheric evolutions during substorms. The most important finding is a nightside pointing plasmaspheric plume observed at 23:05 UT on 21 April 2014 under quiet solar wind and geomagnetic conditions, which drifted from the dusk sector. High correlations between the plasmapause evolutions and the auroral signatures exist during substorms. After substorm onset, the plasmapause erosion and the equatorward expansion of the auroral oval occur almost simultaneously in both MLT and UT, and then both the erosion and the expansion propagate westward and eastward. It is suggested that the plasmaspheric erosion and its MLT propagations are induced by the enhanced earthward plasma convection during substorm period, and the substorm dipolarization causes pitch-angle scattering of plasma sheet electrons and the resulting precipitation excites aurora emissions at the same time.展开更多
A new analytical solution is proposed for steady seepage flow around twin circular tunnels in fully saturated anisotropic ground.The solution is an exact one that fully satisfies all the boundary conditions and precis...A new analytical solution is proposed for steady seepage flow around twin circular tunnels in fully saturated anisotropic ground.The solution is an exact one that fully satisfies all the boundary conditions and precisely considers the different permeabilities along two direc-tions and the interactions between twin tunnels.The solution provides a fast approach for the estimation of the seepage field and a useful tool for design optimization.The solution is successfully addressed using problem equivalence and the Schwartz alternating method com-bined with a mapping function.Using a coordinate transformation of the governing equation,the anisotropic problem of circular tunnels is first equivalent to that of isotropic elliptical tunnels,and the length of the ellipse along the anisotropic axis depends on the anisotropic permeability ratio.The Schwartz alternating method is then employed to address the solution of equivalent elliptical twin tunnel prob-lems,where a mapping function,with which an elliptical tunnel in the half-plane can be mapped into an annulus in the image plane,is introduced to solve the single tunnel problems in each iterative step.The iterative procedure is quite simple and efficient in its calculations and achieves good convergence,and the analytical solution agrees very well with the numerical results to reflect its high precision in the entire ground.Finally,parametric studies are performed to investigate the influences of the anisotropic permeability and tunnel spacing on the seepage field.This is the first study to provide the exact analytical solution of the seepage field of twin tunnel problems in aniso-tropic ground,and the procedure can be extended to multiple tunnel problems.展开更多
Rock bolt anchorage performance is crucial for tunnel support safety.We investigate the mechanical behaviour of reinforced rock and the bolts that reinforce it from the micro-scale to the macro-scale.Bolt pull-out tes...Rock bolt anchorage performance is crucial for tunnel support safety.We investigate the mechanical behaviour of reinforced rock and the bolts that reinforce it from the micro-scale to the macro-scale.Bolt pull-out tests were performed on soft rock using the distinct element method,in which a new contact model that considers bond size,is employed to constrain the main rock mechanical behaviour.The minimum sample width and height values for which the boundary effect can be neglected are first proposed through numerous tests on the influence of sample size on peak load and bond breakage.The influence of sample width is substantially greater than that of sample height.We then select an appropriate sample size to study the influence of bolt embedment length and confining pressure on the mechanical behaviours of the rock and bolt.The results show that increased rock bolt embedment length and confining pressure can increase the peak load;however,the bolt length effect is limited when exceeding the critical anchorage length.In cases without confining pressure,bond breakage occurs in the rock around the grout-rock interface and the breakage zone is rectangular,whereas in cases under confining pressure,the breakage zone presents an inverted cone shape.We use our results to discuss the influence of bond strength at the bolt-grout interface on the peak load and failure mode.The failure mode changes gradually from complex failure to single failure along the bolt-grout interface with decreasing interfacial bond strength.展开更多
基金financially supported by the National Nature Science Foundation of China,Nos.82271508(to YC)82001384(to YC)82271316(to HG)。
文摘Although antipsychotics that act via monoaminergic neurotransmitter modulation have considera ble therapeutic effect,they cannot completely relieve clinical symptoms in patients suffering from psychiatric disorde rs.This may be attributed to the limited range of neurotransmitters that are regulated by psychotropic drugs.Recent findings indicate the need for investigation of psychotropic medications that target less-studied neurotransmitte rs.Among these candidate neurotransmitters,lactate is developing from being a waste metabolite to a glial-neuronal signaling molecule in recent years.Previous studies have suggested that cerebral lactate levels change considerably in numerous psychiatric illnesses;animal experiments have also shown that the supply of exogenous la ctate exerts an antidepressant effect.In this review,we have described how medications targeting newer neurotransmitte rs offer promise in psychiatric diseases;we have also summarized the advances in the use of lactate(and its corresponding signaling pathways)as a signaling molecule.In addition,we have described the alterations in brain lactate levels in depression,anxiety,bipolar disorder,and schizophrenia and have indicated the challenges that need to be overcome before brain lactate can be used as a therapeutic target in psychopharmacology.
基金supported by National Natural Science Foundation of China (41674155 and 41274147)Youth Innovation Promotion Association of Chinese Academy of Sciences (No.2017258)Key Research Project of Chinese Academy of Sciences:Application Research on the Scientific Data from Chang’E-3 Mission (KGZD-EW-603)
文摘The plasmapause locations determined from the Chang'e-3(CE-3) Extreme Ultraviolet Camera(EUVC) images and the auroral boundaries determined from the Defense Meteorological Satellite Program(DMSP) Special Sensor Ultraviolet Spectrographic Imager(SSUSI) images are used to investigate the plasmaspheric evolutions during substorms. The most important finding is a nightside pointing plasmaspheric plume observed at 23:05 UT on 21 April 2014 under quiet solar wind and geomagnetic conditions, which drifted from the dusk sector. High correlations between the plasmapause evolutions and the auroral signatures exist during substorms. After substorm onset, the plasmapause erosion and the equatorward expansion of the auroral oval occur almost simultaneously in both MLT and UT, and then both the erosion and the expansion propagate westward and eastward. It is suggested that the plasmaspheric erosion and its MLT propagations are induced by the enhanced earthward plasma convection during substorm period, and the substorm dipolarization causes pitch-angle scattering of plasma sheet electrons and the resulting precipitation excites aurora emissions at the same time.
基金supported by the National Natural Science Foundation of China(Grant Nos.11872281,51639008,51890911)the State Key Laboratory of Disaster Reduction in Civil Engineering(SLDRCE19-A-06).The supports are greatly appreciated.
文摘A new analytical solution is proposed for steady seepage flow around twin circular tunnels in fully saturated anisotropic ground.The solution is an exact one that fully satisfies all the boundary conditions and precisely considers the different permeabilities along two direc-tions and the interactions between twin tunnels.The solution provides a fast approach for the estimation of the seepage field and a useful tool for design optimization.The solution is successfully addressed using problem equivalence and the Schwartz alternating method com-bined with a mapping function.Using a coordinate transformation of the governing equation,the anisotropic problem of circular tunnels is first equivalent to that of isotropic elliptical tunnels,and the length of the ellipse along the anisotropic axis depends on the anisotropic permeability ratio.The Schwartz alternating method is then employed to address the solution of equivalent elliptical twin tunnel prob-lems,where a mapping function,with which an elliptical tunnel in the half-plane can be mapped into an annulus in the image plane,is introduced to solve the single tunnel problems in each iterative step.The iterative procedure is quite simple and efficient in its calculations and achieves good convergence,and the analytical solution agrees very well with the numerical results to reflect its high precision in the entire ground.Finally,parametric studies are performed to investigate the influences of the anisotropic permeability and tunnel spacing on the seepage field.This is the first study to provide the exact analytical solution of the seepage field of twin tunnel problems in aniso-tropic ground,and the procedure can be extended to multiple tunnel problems.
基金support for this study from the National Natural Science Foundation of China(Grant Nos.11872281,11572228)the State Key Laboratory of Disaster Reduction in Civil Engineering(SLDRCE19-A-06).
文摘Rock bolt anchorage performance is crucial for tunnel support safety.We investigate the mechanical behaviour of reinforced rock and the bolts that reinforce it from the micro-scale to the macro-scale.Bolt pull-out tests were performed on soft rock using the distinct element method,in which a new contact model that considers bond size,is employed to constrain the main rock mechanical behaviour.The minimum sample width and height values for which the boundary effect can be neglected are first proposed through numerous tests on the influence of sample size on peak load and bond breakage.The influence of sample width is substantially greater than that of sample height.We then select an appropriate sample size to study the influence of bolt embedment length and confining pressure on the mechanical behaviours of the rock and bolt.The results show that increased rock bolt embedment length and confining pressure can increase the peak load;however,the bolt length effect is limited when exceeding the critical anchorage length.In cases without confining pressure,bond breakage occurs in the rock around the grout-rock interface and the breakage zone is rectangular,whereas in cases under confining pressure,the breakage zone presents an inverted cone shape.We use our results to discuss the influence of bond strength at the bolt-grout interface on the peak load and failure mode.The failure mode changes gradually from complex failure to single failure along the bolt-grout interface with decreasing interfacial bond strength.