Adult neural stem cells are neurogenesis progenitor cells that play an important role in neurogenesis.Therefore,neural regeneration may be a promising target for treatment of many neurological illnesses.The regenerati...Adult neural stem cells are neurogenesis progenitor cells that play an important role in neurogenesis.Therefore,neural regeneration may be a promising target for treatment of many neurological illnesses.The regenerative capacity of adult neural stem cells can be chara cterized by two states:quiescent and active.Quiescent adult neural stem cells are more stable and guarantee the quantity and quality of the adult neural stem cell pool.Active adult neural stem cells are chara cterized by rapid proliferation and differentiation into neurons which allow for integration into neural circuits.This review focuses on diffe rences between quiescent and active adult neural stem cells in nutrition metabolism and protein homeostasis.Furthermore,we discuss the physiological significance and underlying advantages of these diffe rences.Due to the limited number of adult neural stem cells studies,we refe rred to studies of embryonic adult neural stem cells or non-mammalian adult neural stem cells to evaluate specific mechanisms.展开更多
Magnetic reconnection driven by a capacitor coil target is an innovative way to investigate low-βmagnetic reconnection in the laboratory,whereβis the ratio of particle thermal pressure to magnetic pressure.Low-βmag...Magnetic reconnection driven by a capacitor coil target is an innovative way to investigate low-βmagnetic reconnection in the laboratory,whereβis the ratio of particle thermal pressure to magnetic pressure.Low-βmagnetic reconnection frequently occurs in the Earth’s magnetosphere,where the plasma is characterized byβ≲0.01.In this paper,we analyze electron acceleration during magnetic reconnection and its effects on the electron energy spectrum via particle-in-cell simulations informed by parameters obtained from experiments.We note that magnetic reconnection starts when the current sheet is down to about three electron inertial lengths.From a quantitative comparison of the different mechanisms underlying the electron acceleration in low-βreconnection driven by coil targets,we find that the electron acceleration is dominated by the betatron mechanism,whereas the parallel electric field plays a cooling role and Fermi acceleration is negligible.The accelerated electrons produce a hardened power-law spectrum with a high-energy bump.We find that injecting electrons into the current sheet is likely to be essential for further acceleration.In addition,we perform simulations for both a double-coil co-directional magnetic field and a single-coil one to eliminate the possibility of direct acceleration of electrons beyond thermal energies by the coil current.The squeeze between the two coil currents can only accelerate electrons inefficiently before reconnection.The simulation results provide insights to guide future experimental improvements in low-βmagnetic reconnection driven by capacitor coil targets.展开更多
All dielectrics exhibit electrostriction,i.e.,display a quadratic strain response to an electric field compared to the linear strain dependence of piezoelectrics.As such,there is significant interest in discovering ne...All dielectrics exhibit electrostriction,i.e.,display a quadratic strain response to an electric field compared to the linear strain dependence of piezoelectrics.As such,there is significant interest in discovering new electrostrictors with enhanced electrostrictive coefficients,especially as electrostrictors can exhibit effective piezoelectricity when a bias electric field is applied.We present the results of a study combining data mining and first-principles computations that indicate that there exists a group of iodides,bromides,and chlorides that have electrostrictive coefficients exceeding 10 m^(4)C^(–2)which are substantially higher than typical oxide electrostrictive ceramics and polymers.The corresponding effective piezoelectric voltage coefficients are three orders of magnitude larger than lead zirconate titanate.展开更多
基金supported by the National Natural Science Foundation of China,No.82171336(to XX)。
文摘Adult neural stem cells are neurogenesis progenitor cells that play an important role in neurogenesis.Therefore,neural regeneration may be a promising target for treatment of many neurological illnesses.The regenerative capacity of adult neural stem cells can be chara cterized by two states:quiescent and active.Quiescent adult neural stem cells are more stable and guarantee the quantity and quality of the adult neural stem cell pool.Active adult neural stem cells are chara cterized by rapid proliferation and differentiation into neurons which allow for integration into neural circuits.This review focuses on diffe rences between quiescent and active adult neural stem cells in nutrition metabolism and protein homeostasis.Furthermore,we discuss the physiological significance and underlying advantages of these diffe rences.Due to the limited number of adult neural stem cells studies,we refe rred to studies of embryonic adult neural stem cells or non-mammalian adult neural stem cells to evaluate specific mechanisms.
基金This work was supported by the National Key R&D Program of China(Grant Nos.2022YFA1603200 and 2022YFA1603203)the National Natural Science Foundation of China(Grant Nos.12325305,12175018,12135001,and 12075030)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA25030700).We express our gratitude to X.-G.Wang,K.Huang,X.-X.Yuan,and C.-Q.Xing for their discussions.Thanks to Beijing Super Cloud Computing Center for providing the computational resources.
文摘Magnetic reconnection driven by a capacitor coil target is an innovative way to investigate low-βmagnetic reconnection in the laboratory,whereβis the ratio of particle thermal pressure to magnetic pressure.Low-βmagnetic reconnection frequently occurs in the Earth’s magnetosphere,where the plasma is characterized byβ≲0.01.In this paper,we analyze electron acceleration during magnetic reconnection and its effects on the electron energy spectrum via particle-in-cell simulations informed by parameters obtained from experiments.We note that magnetic reconnection starts when the current sheet is down to about three electron inertial lengths.From a quantitative comparison of the different mechanisms underlying the electron acceleration in low-βreconnection driven by coil targets,we find that the electron acceleration is dominated by the betatron mechanism,whereas the parallel electric field plays a cooling role and Fermi acceleration is negligible.The accelerated electrons produce a hardened power-law spectrum with a high-energy bump.We find that injecting electrons into the current sheet is likely to be essential for further acceleration.In addition,we perform simulations for both a double-coil co-directional magnetic field and a single-coil one to eliminate the possibility of direct acceleration of electrons beyond thermal energies by the coil current.The squeeze between the two coil currents can only accelerate electrons inefficiently before reconnection.The simulation results provide insights to guide future experimental improvements in low-βmagnetic reconnection driven by capacitor coil targets.
基金Authors A.G.,S.K.N.,and S.P.A.thank the Air Force Research Laboratory,Materials and Manufacturing Directorate(AFRL/RXMS)for support via Contract No.FA8650-18-C-5700J.Y.and P.E.J.have been supported by the ANR-19-ASTR-0024-01 and ANR-20-CE08-0012-1 grants.
文摘All dielectrics exhibit electrostriction,i.e.,display a quadratic strain response to an electric field compared to the linear strain dependence of piezoelectrics.As such,there is significant interest in discovering new electrostrictors with enhanced electrostrictive coefficients,especially as electrostrictors can exhibit effective piezoelectricity when a bias electric field is applied.We present the results of a study combining data mining and first-principles computations that indicate that there exists a group of iodides,bromides,and chlorides that have electrostrictive coefficients exceeding 10 m^(4)C^(–2)which are substantially higher than typical oxide electrostrictive ceramics and polymers.The corresponding effective piezoelectric voltage coefficients are three orders of magnitude larger than lead zirconate titanate.
