3, 4-methylenedioxymethamphetamine （MDMA; also known as ＇ecstasy＇） has been shown to impair learning and spatial memory in adult and neonatal rats. Many studies have focused on the acute effects of MDMA on memory....3, 4-methylenedioxymethamphetamine （MDMA; also known as ＇ecstasy＇） has been shown to impair learning and spatial memory in adult and neonatal rats. Many studies have focused on the acute effects of MDMA on memory. In the present study, we intraperitoneally administered MDMA （0, 5, 10, 20 mg/kg） to adult male rats to investigate the effects of different doses on rat spatial memory in the Morris water maze, body temperature, and mortality, twice a day, for 7 successive days. The results indicated that MDMA impaired spatial memory dose-dependently, with the highest dose （20 mg/kg） exerting the strongest effects. In addition, MDMA also caused hyperthermia and increased mortality in rats展开更多
Learning processes are extensively studied in behavioral neuroscience. As experimental models, Morris Water Maze (MWM) and Spontaneous Alternation (SA) represent two of the most frequently used laboratory tests to res...Learning processes are extensively studied in behavioral neuroscience. As experimental models, Morris Water Maze (MWM) and Spontaneous Alternation (SA) represent two of the most frequently used laboratory tests to respectively address spatial vs non-spatial tasks. Several factors have been shown to impact on those learning, including strain, gender, apparatus, conditioning, vision, lighting conditions and stress level. In order to focus on the later, we compared the acquisition of two learning tasks (MWM and SA) in BALB/c and A/J mice, which are known as fearful and stress-sensitive strains. Here, we report that BALB/c mice exhibited higher performances than A/J mice in the MWM (i.e. spatial reference memory task), whereas A/J mice performed better in the SA (i.e. spatial working memory task). These results indicate dissociated processes in the acquisition of spatial vs non-spatial tasks, and emphasize a varying influence of emotional reactivity on different forms of cognition.展开更多
To study the water absorption of hollow glass microspheres(HGMs)composite epoxy resin solid buoyancy materials in the marine environment and its effect on the mechanical properties,the water absorption was measured by...To study the water absorption of hollow glass microspheres(HGMs)composite epoxy resin solid buoyancy materials in the marine environment and its effect on the mechanical properties,the water absorption was measured by immersing the material in distilled water for 36 days at ambient temperature and fitted to Fick’s second law.The strength of materials before and after water absorption were tested by uniaxial experiments,and the effects of the filling ratio and water absorption on the mechanical properties of the materials were analyzed and explained.Finally,the failure modes and mechanism of the hollow glass microspheres composite material were explicated from the microscopic level by scanning electron microscope(SEM).This research will help solve the problems of solid buoyancy materials in ocean engineering applications.展开更多
Water–rock interaction(WRI)is a topic of interest in geology and geotechnical engineering.Many geological hazards and engineering safety problems are severe under the WRI.This study focuses on the water weakening of ...Water–rock interaction(WRI)is a topic of interest in geology and geotechnical engineering.Many geological hazards and engineering safety problems are severe under the WRI.This study focuses on the water weakening of rock strength and its infuencing factors(water content,immersion time,and wetting–drying cycles).The strength of the rock mass decreases to varying degrees with water content,immersion time,and wetting–drying cycles depending on the rock mass type and mineral composition.The corresponding acoustic emission count and intensity and infrared radiation intensity also weaken accordingly.WRI enhances the plasticity of rock mass and reduces its brittleness.Various microscopic methods for studying the pore characterization and weakening mechanism of the WRI were compared and analyzed.Various methods should be adopted to study the pore evolution of WRI comprehensively.Microscopic methods are used to study the weakening mechanism of WRI.In future work,the mechanical parameters of rocks weakened under long-term water immersion(over years)should be considered,and more attention should be paid to how the laboratory scale is applied to the engineering scale.展开更多
A moderate stress such as cold water swimming can raise the tolerance of the body to potentially injurious events. However, little is known about the mechanism of beneficial effects induced by moderate stress. In this...A moderate stress such as cold water swimming can raise the tolerance of the body to potentially injurious events. However, little is known about the mechanism of beneficial effects induced by moderate stress. In this study, we used a classic rat model of traumatic brain injury to test the hypothesis that cold water swimming preconditioning improved the recovery of cognitive functions and explored the mechanisms. Results showed that after traumatic brain injury, pre-conditioned rats（cold water swimming for 3 minutes at 4℃） spent a significantly higher percent of times in the goal quadrant of cold water swim, and escape latencies were shorter than for non-pretreated rats. The number of circulating endothelial progenitor cells was significantly higher in pre-conditioned rats than those without pretreatment at 0, 3, 6 and 24 hours after traumatic brain injury. Immunohistochemical staining and Von Willebrand factor staining demonstrated that the number of CD34~＋ stem cells and new blood vessels in the injured hippocampus tissue increased significantly in pre-conditioned rats. These data suggest that pretreatment with cold water swimming could promote the proliferation of endothelial progenitor cells and angiogenesis in the peripheral blood and hippocampus. It also ameliorated cognitive deficits caused by experimental traumatic brain injury.展开更多
基金a grant from the Substance Abuse and Dependence Research Center University of Social Welfare and Rehabilitation Sciences, No. 313-126417Tehran University of Medical Sciences, No. P/664
文摘3, 4-methylenedioxymethamphetamine （MDMA; also known as ＇ecstasy＇） has been shown to impair learning and spatial memory in adult and neonatal rats. Many studies have focused on the acute effects of MDMA on memory. In the present study, we intraperitoneally administered MDMA （0, 5, 10, 20 mg/kg） to adult male rats to investigate the effects of different doses on rat spatial memory in the Morris water maze, body temperature, and mortality, twice a day, for 7 successive days. The results indicated that MDMA impaired spatial memory dose-dependently, with the highest dose （20 mg/kg） exerting the strongest effects. In addition, MDMA also caused hyperthermia and increased mortality in rats
文摘Learning processes are extensively studied in behavioral neuroscience. As experimental models, Morris Water Maze (MWM) and Spontaneous Alternation (SA) represent two of the most frequently used laboratory tests to respectively address spatial vs non-spatial tasks. Several factors have been shown to impact on those learning, including strain, gender, apparatus, conditioning, vision, lighting conditions and stress level. In order to focus on the later, we compared the acquisition of two learning tasks (MWM and SA) in BALB/c and A/J mice, which are known as fearful and stress-sensitive strains. Here, we report that BALB/c mice exhibited higher performances than A/J mice in the MWM (i.e. spatial reference memory task), whereas A/J mice performed better in the SA (i.e. spatial working memory task). These results indicate dissociated processes in the acquisition of spatial vs non-spatial tasks, and emphasize a varying influence of emotional reactivity on different forms of cognition.
基金financially supported by the Natural Science Foundation of Liaoning Province(Grant No.2021-MS-109)。
文摘To study the water absorption of hollow glass microspheres(HGMs)composite epoxy resin solid buoyancy materials in the marine environment and its effect on the mechanical properties,the water absorption was measured by immersing the material in distilled water for 36 days at ambient temperature and fitted to Fick’s second law.The strength of materials before and after water absorption were tested by uniaxial experiments,and the effects of the filling ratio and water absorption on the mechanical properties of the materials were analyzed and explained.Finally,the failure modes and mechanism of the hollow glass microspheres composite material were explicated from the microscopic level by scanning electron microscope(SEM).This research will help solve the problems of solid buoyancy materials in ocean engineering applications.
基金the National Natural Science Foundation of China(52104155)Natural Science Foundation of Beijing(8212032)Fundamental Research Funds for the Central Universities(2023YQNY).
文摘Water–rock interaction(WRI)is a topic of interest in geology and geotechnical engineering.Many geological hazards and engineering safety problems are severe under the WRI.This study focuses on the water weakening of rock strength and its infuencing factors(water content,immersion time,and wetting–drying cycles).The strength of the rock mass decreases to varying degrees with water content,immersion time,and wetting–drying cycles depending on the rock mass type and mineral composition.The corresponding acoustic emission count and intensity and infrared radiation intensity also weaken accordingly.WRI enhances the plasticity of rock mass and reduces its brittleness.Various microscopic methods for studying the pore characterization and weakening mechanism of the WRI were compared and analyzed.Various methods should be adopted to study the pore evolution of WRI comprehensively.Microscopic methods are used to study the weakening mechanism of WRI.In future work,the mechanical parameters of rocks weakened under long-term water immersion(over years)should be considered,and more attention should be paid to how the laboratory scale is applied to the engineering scale.
基金supported by a grant from the Incubation Project of Natural Science Foundation of Tianjin Medical University General Hospital in China,No.303071901401the Natural Science Foundation of Tianjin of China,No.13JCZDJC30800the National Natural Science Foundation of China,No.81271361 and 81330029
文摘A moderate stress such as cold water swimming can raise the tolerance of the body to potentially injurious events. However, little is known about the mechanism of beneficial effects induced by moderate stress. In this study, we used a classic rat model of traumatic brain injury to test the hypothesis that cold water swimming preconditioning improved the recovery of cognitive functions and explored the mechanisms. Results showed that after traumatic brain injury, pre-conditioned rats（cold water swimming for 3 minutes at 4℃） spent a significantly higher percent of times in the goal quadrant of cold water swim, and escape latencies were shorter than for non-pretreated rats. The number of circulating endothelial progenitor cells was significantly higher in pre-conditioned rats than those without pretreatment at 0, 3, 6 and 24 hours after traumatic brain injury. Immunohistochemical staining and Von Willebrand factor staining demonstrated that the number of CD34~＋ stem cells and new blood vessels in the injured hippocampus tissue increased significantly in pre-conditioned rats. These data suggest that pretreatment with cold water swimming could promote the proliferation of endothelial progenitor cells and angiogenesis in the peripheral blood and hippocampus. It also ameliorated cognitive deficits caused by experimental traumatic brain injury.
