Background:College students face significant academic and physiological changes,making them more susceptible to psychological issues such as depression,self-injury,and suicidal ideation.Feelings of defeat can exacerba...Background:College students face significant academic and physiological changes,making them more susceptible to psychological issues such as depression,self-injury,and suicidal ideation.Feelings of defeat can exacerbate these risks by increasing academic stress.However,interpersonal relationships can moderate the impact of academic stress on students’mental health.Utilizing the presage–process–product model,this study aims to empirically investigate how feelings of defeat influence depression,self-injury,and suicidal ideation among college students.Additionally,it explores the mediating role of academic stress and the moderating role of various types of interpersonal relationships.Methods:A total of 1612 college students(750 females,862 males,mean age=19.64±0.62 years)were recruited through cluster sampling.Data were collected via offline questionnaires administered by a trained psychology teacher and a postgraduate student,ensuring high reliability with two examiners per class.Latent profile analysis(LPA)was used to examine the impact of defeat on mental health outcomes,while mediation analysis was conducted to assess the roles of academic stress and interpersonal relationships.Results:1.Defeat is identified as a significant risk factor for mental health issues among college students;2.Four distinct patterns of interpersonal relationships were identified:the interpersonal-relationship risk group,the father–child-relationship high-risk group,the general interpersonal-relationship group,and the superior interpersonal-relationship group;3.Academic stress partially mediates the relationship between defeat and mental health issues such as depression,self-injury,and suicidal ideation;4.Different interpersonal relationship models moderate the impact of academic stress on depression and suicidal ideation.Conclusion:Defeat is a significant risk factor for mental health problems in college students.Academic stress partially mediates the negative impact of defeat on mental health,while patterns of interpersonal relationships moderate this impact.Effective early prevention and intervention should focus on monitoring students’stress levels and fostering warm,positive parent–child relationships.展开更多
Recent genome studies indicate that tree shrew is in the order or a closest sister of primates,and thus may be one of the best animals to model human diseases.In this paper,we report on a social defeat model of depres...Recent genome studies indicate that tree shrew is in the order or a closest sister of primates,and thus may be one of the best animals to model human diseases.In this paper,we report on a social defeat model of depression in tree shrew（Tupaia belangeri chinensis）.Two male tree shrews were housed in a pair-cage consisting of two independent cages separated by a wire mesh partition with a door connecting the two cages.After one week adaptation,the connecting door was opened and a brief fighting occurs between the two male tree shrews and this social conflict session consisted of 1 h direct conflict（fighting） and 23 h indirect influence（e.g.smell,visual cues） per day for 21 days.The defeated tree shrew was considered the subordinate.Compared with na？ve animals,subordinate tree shrews at the final week of social conflict session showed alterations in body weight,locomotion,avoidance behavior and urinary cortisol levels.Remarkably,these alterations persisted for over two weeks.We also report on a novel captive conditioning model of learning and memory in tree shrew.An automatic trapping cage was placed in a small closed room with a freely-moving tree shrew.For the first four trials,the tree shrew was not trapped when it entered the cage and ate the bait apple,but it was trapped and kept in the cage for 1 h on the fifth trial.Latency was defined as the time between release of the tree shrew and when it entered the captive cage.Latencies during the five trials indicated adaptation.A test trial 24 h later was used to measure whether the one-trial trapping during the fifth trial could form captive memory.Tree shrews showed much longer trapping latencies in the test trial than the adaptation trials.The N-methyl-d-aspartate（NMDA） receptor antagonist MK-801（0.2 mg/kg,i.p.）,known to prevent the formation of memory,did not affect latencies in the adaptation trails,but did block captive memory as it led to much shorter trapping latencies compared to saline treatment in the test trial.These results demonstrate a chronic social defeat model of depression and a novel one-trial captive conditioning model for learning and memory in tree shrews,which are important for mechanism studies of depression,learning,memory,and preclinical evaluation for new antidepressants.展开更多
Brain-derived neurotrophic factor is a key factor in stress adaptation and avoidance of a social stress behavioral response.Recent studies have shown that brain-derived neurotrophic factor expression in stressed mice ...Brain-derived neurotrophic factor is a key factor in stress adaptation and avoidance of a social stress behavioral response.Recent studies have shown that brain-derived neurotrophic factor expression in stressed mice is brain region–specific,particularly involving the corticolimbic system,including the ventral tegmental area,nucleus accumbens,prefrontal cortex,amygdala,and hippocampus.Determining how brain-derived neurotrophic factor participates in stress processing in different brain regions will deepen our understanding of social stress psychopathology.In this review,we discuss the expression and regulation of brain-derived neurotrophic factor in stress-sensitive brain regions closely related to the pathophysiology of depression.We focused on associated molecular pathways and neural circuits,with special attention to the brain-derived neurotrophic factor–tropomyosin receptor kinase B signaling pathway and the ventral tegmental area–nucleus accumbens dopamine circuit.We determined that stress-induced alterations in brain-derived neurotrophic factor levels are likely related to the nature,severity,and duration of stress,especially in the above-mentioned brain regions of the corticolimbic system.Therefore,BDNF might be a biological indicator regulating stress-related processes in various brain regions.展开更多
Old fisherman Santiago fight bravely,the battle he loses in the flesh can be one he wins in the spirit.The old man should be regarded as a noble hero,if tragic,a failure for his physical suffers and loses of the big f...Old fisherman Santiago fight bravely,the battle he loses in the flesh can be one he wins in the spirit.The old man should be regarded as a noble hero,if tragic,a failure for his physical suffers and loses of the big fish,not a failure for his spirit of optimism,confidence,wisdom of spirits,perseverance and bravery.He wins the interior triumph from physical defeat.Whether to be a triumphed hero or a defeated failure is up to a person's efforts.展开更多
Replica scaled impact experiments with unconfined ceramic targets have shown that the transition velocity,i.e.,the impact velocity at which interface defeat ceases and ceramic penetration occurs,decreased as the lengt...Replica scaled impact experiments with unconfined ceramic targets have shown that the transition velocity,i.e.,the impact velocity at which interface defeat ceases and ceramic penetration occurs,decreased as the length scale increased.A possible explanation of how this scale effect is related to the formation of a cone crack in the ceramic has been presented by the authors in an earlier paper.Here,the influence of confinement and prestress on cone cracking and transition velocity is investigated.The hypothesis is that prestress will suppress the formation and growth of the cone crack by lowering the driving stress.A set of impact experiments has been performed in which the transition velocity for four different levels of prestress has been determined.The transition velocities as a function of the level of confining prestress is compared to an analytical model for the influence of prestress on the formation and extension of the cone crack in the ceramic material.Both experiments and model indicate that prestress has a strong influence on the transition from interface defeat to penetration,although the model underestimates the influence of prestress.展开更多
OBJECTIVE Ginsenoside Rb1(Rb1),an important bioactive ingredient of Panax ginseng,has potent neuroprotective effects.The objective of the study is to elucidate the impact of Rb1 treatment on chronic social defeat stre...OBJECTIVE Ginsenoside Rb1(Rb1),an important bioactive ingredient of Panax ginseng,has potent neuroprotective effects.The objective of the study is to elucidate the impact of Rb1 treatment on chronic social defeat stress(CSDS)-induced depressive-like behaviors and its related mechanism.METHODS AND RE⁃SULTS The daily oral administration of Rb1(35 and 70 mg·kg-1)and imipramine(15 mg·kg-1)for 28 d significantly reversed the social avoidance behavior,anhedonia,and behavioral despair via CSDS exposure,as demonstrated by the consid⁃erable elevation in the time in the zone in social interaction test and consumption of sucrose solu⁃tion in sucrose preference test and decrease of immobility time in forced swim test.Moreover,Rb1 obviously restored the CSDS-induced decrease of BDNF-signaling pathway and hippo⁃campal neurogenesis.Rb1 significantly increased the hippocampal levels of ERK,AKT,and CREB phosphorylation and increased the number of DCX+cells in DG.Importantly,the antidepres⁃sant effects of Rb1 were completely blocked in mice by using K252a(the nonselective tyrosine kinase B inhibitor).CONCLUSION Rb1 exerts promising antidepressant-like effects in mice with CSDS-induced depression,and its effects was facilitated by enhancing the BDNF signaling cas⁃cade and up-regulation of hippocampal neuro⁃genesis.展开更多
Despite all the human efforts and monetary investment over the last few decades,cancer is still a devastating threat to our life expectancy and quality of life in many parts of the world.The etiology of cancer varies....Despite all the human efforts and monetary investment over the last few decades,cancer is still a devastating threat to our life expectancy and quality of life in many parts of the world.The etiology of cancer varies.The genetic and epigenetic causes of cancer are heterogeneous and multifaceted.Early detection is still a展开更多
The interface defeat phenomenon always occurs when a long-rod projectile impacting on the ceramic target with certain velocity,i.e.,the projectile is forced to flow radially on the surface of ceramic plates for a peri...The interface defeat phenomenon always occurs when a long-rod projectile impacting on the ceramic target with certain velocity,i.e.,the projectile is forced to flow radially on the surface of ceramic plates for a period of time without significant penetration.Interface defeat has a direct effect upon the ballistic performance of the armor piercing projectile,which is studied numerically and theoretically at present.Firstly,by modeling the projectiles and ceramic targets with the SPH(Smoothed Particle Hydrodynamics)particles and Lagrange finite elements,the systematic numerical simulations on interface defeat are performed with the commercial finite element program AUTODYN.Three different responses,i.e.,complete interface defeat,dwell and direct penetration,are reproduced in different types of ceramic targets(bare,buffered,radially confined and oblique).Furthermore,by adopting the validated numerical algorithms,constitutive models and the corresponding material parameters,the influences of projectile(material,diameter,nose shape),constitutive models of ceramic(JH-1 and JH-2 models),buffer and cover plate(thickness,constraints,material),as well as the prestress acted on the target(radial and hydrostatic) on the interface defeat(transition velocity and dwell time) are syste matically investigated.Finally,based on the energy conservation approach and taking the strain rate effect of ceramic material into account,a modified model for predicting the upper limit of transition velocity is proposed and validated.The present work and derived conclusions can provide helpful reference for the design and optimization of both the long-rod projectile and ceramic armor.展开更多
基金funded by the Humanities and Social Sciences Foundation of the Ministry of Education(23JDSZ3163)the 2023 Project of the“14th Five-Year Plan”for Education Science of Shandong Province and the Achievements of the Famous Tutors’Workshop in Shandong Province(202405).
文摘Background:College students face significant academic and physiological changes,making them more susceptible to psychological issues such as depression,self-injury,and suicidal ideation.Feelings of defeat can exacerbate these risks by increasing academic stress.However,interpersonal relationships can moderate the impact of academic stress on students’mental health.Utilizing the presage–process–product model,this study aims to empirically investigate how feelings of defeat influence depression,self-injury,and suicidal ideation among college students.Additionally,it explores the mediating role of academic stress and the moderating role of various types of interpersonal relationships.Methods:A total of 1612 college students(750 females,862 males,mean age=19.64±0.62 years)were recruited through cluster sampling.Data were collected via offline questionnaires administered by a trained psychology teacher and a postgraduate student,ensuring high reliability with two examiners per class.Latent profile analysis(LPA)was used to examine the impact of defeat on mental health outcomes,while mediation analysis was conducted to assess the roles of academic stress and interpersonal relationships.Results:1.Defeat is identified as a significant risk factor for mental health issues among college students;2.Four distinct patterns of interpersonal relationships were identified:the interpersonal-relationship risk group,the father–child-relationship high-risk group,the general interpersonal-relationship group,and the superior interpersonal-relationship group;3.Academic stress partially mediates the relationship between defeat and mental health issues such as depression,self-injury,and suicidal ideation;4.Different interpersonal relationship models moderate the impact of academic stress on depression and suicidal ideation.Conclusion:Defeat is a significant risk factor for mental health problems in college students.Academic stress partially mediates the negative impact of defeat on mental health,while patterns of interpersonal relationships moderate this impact.Effective early prevention and intervention should focus on monitoring students’stress levels and fostering warm,positive parent–child relationships.
基金supported by grants KSCX2-EW-R-12 and KSCX2-EW-J-23 from the Chinese Academy of Sciences
文摘Recent genome studies indicate that tree shrew is in the order or a closest sister of primates,and thus may be one of the best animals to model human diseases.In this paper,we report on a social defeat model of depression in tree shrew（Tupaia belangeri chinensis）.Two male tree shrews were housed in a pair-cage consisting of two independent cages separated by a wire mesh partition with a door connecting the two cages.After one week adaptation,the connecting door was opened and a brief fighting occurs between the two male tree shrews and this social conflict session consisted of 1 h direct conflict（fighting） and 23 h indirect influence（e.g.smell,visual cues） per day for 21 days.The defeated tree shrew was considered the subordinate.Compared with na？ve animals,subordinate tree shrews at the final week of social conflict session showed alterations in body weight,locomotion,avoidance behavior and urinary cortisol levels.Remarkably,these alterations persisted for over two weeks.We also report on a novel captive conditioning model of learning and memory in tree shrew.An automatic trapping cage was placed in a small closed room with a freely-moving tree shrew.For the first four trials,the tree shrew was not trapped when it entered the cage and ate the bait apple,but it was trapped and kept in the cage for 1 h on the fifth trial.Latency was defined as the time between release of the tree shrew and when it entered the captive cage.Latencies during the five trials indicated adaptation.A test trial 24 h later was used to measure whether the one-trial trapping during the fifth trial could form captive memory.Tree shrews showed much longer trapping latencies in the test trial than the adaptation trials.The N-methyl-d-aspartate（NMDA） receptor antagonist MK-801（0.2 mg/kg,i.p.）,known to prevent the formation of memory,did not affect latencies in the adaptation trails,but did block captive memory as it led to much shorter trapping latencies compared to saline treatment in the test trial.These results demonstrate a chronic social defeat model of depression and a novel one-trial captive conditioning model for learning and memory in tree shrews,which are important for mechanism studies of depression,learning,memory,and preclinical evaluation for new antidepressants.
基金supported financially by the National Natural Science Foundation of China,No.82071272(to YZ).
文摘Brain-derived neurotrophic factor is a key factor in stress adaptation and avoidance of a social stress behavioral response.Recent studies have shown that brain-derived neurotrophic factor expression in stressed mice is brain region–specific,particularly involving the corticolimbic system,including the ventral tegmental area,nucleus accumbens,prefrontal cortex,amygdala,and hippocampus.Determining how brain-derived neurotrophic factor participates in stress processing in different brain regions will deepen our understanding of social stress psychopathology.In this review,we discuss the expression and regulation of brain-derived neurotrophic factor in stress-sensitive brain regions closely related to the pathophysiology of depression.We focused on associated molecular pathways and neural circuits,with special attention to the brain-derived neurotrophic factor–tropomyosin receptor kinase B signaling pathway and the ventral tegmental area–nucleus accumbens dopamine circuit.We determined that stress-induced alterations in brain-derived neurotrophic factor levels are likely related to the nature,severity,and duration of stress,especially in the above-mentioned brain regions of the corticolimbic system.Therefore,BDNF might be a biological indicator regulating stress-related processes in various brain regions.
文摘Old fisherman Santiago fight bravely,the battle he loses in the flesh can be one he wins in the spirit.The old man should be regarded as a noble hero,if tragic,a failure for his physical suffers and loses of the big fish,not a failure for his spirit of optimism,confidence,wisdom of spirits,perseverance and bravery.He wins the interior triumph from physical defeat.Whether to be a triumphed hero or a defeated failure is up to a person's efforts.
基金funded by the Swedish Armed Forces and by the Army Research Laboratory through US Naval Regional Contracting Centre,Contract No.W911NF0810271
文摘Replica scaled impact experiments with unconfined ceramic targets have shown that the transition velocity,i.e.,the impact velocity at which interface defeat ceases and ceramic penetration occurs,decreased as the length scale increased.A possible explanation of how this scale effect is related to the formation of a cone crack in the ceramic has been presented by the authors in an earlier paper.Here,the influence of confinement and prestress on cone cracking and transition velocity is investigated.The hypothesis is that prestress will suppress the formation and growth of the cone crack by lowering the driving stress.A set of impact experiments has been performed in which the transition velocity for four different levels of prestress has been determined.The transition velocities as a function of the level of confining prestress is compared to an analytical model for the influence of prestress on the formation and extension of the cone crack in the ceramic material.Both experiments and model indicate that prestress has a strong influence on the transition from interface defeat to penetration,although the model underestimates the influence of prestress.
基金Ministry of Science and Tech⁃nology of China(2017ZX09301029)and Space Medical Experiment Project of China Manned Space Program(HYZHXM05003)。
文摘OBJECTIVE Ginsenoside Rb1(Rb1),an important bioactive ingredient of Panax ginseng,has potent neuroprotective effects.The objective of the study is to elucidate the impact of Rb1 treatment on chronic social defeat stress(CSDS)-induced depressive-like behaviors and its related mechanism.METHODS AND RE⁃SULTS The daily oral administration of Rb1(35 and 70 mg·kg-1)and imipramine(15 mg·kg-1)for 28 d significantly reversed the social avoidance behavior,anhedonia,and behavioral despair via CSDS exposure,as demonstrated by the consid⁃erable elevation in the time in the zone in social interaction test and consumption of sucrose solu⁃tion in sucrose preference test and decrease of immobility time in forced swim test.Moreover,Rb1 obviously restored the CSDS-induced decrease of BDNF-signaling pathway and hippo⁃campal neurogenesis.Rb1 significantly increased the hippocampal levels of ERK,AKT,and CREB phosphorylation and increased the number of DCX+cells in DG.Importantly,the antidepres⁃sant effects of Rb1 were completely blocked in mice by using K252a(the nonselective tyrosine kinase B inhibitor).CONCLUSION Rb1 exerts promising antidepressant-like effects in mice with CSDS-induced depression,and its effects was facilitated by enhancing the BDNF signaling cas⁃cade and up-regulation of hippocampal neuro⁃genesis.
文摘Despite all the human efforts and monetary investment over the last few decades,cancer is still a devastating threat to our life expectancy and quality of life in many parts of the world.The etiology of cancer varies.The genetic and epigenetic causes of cancer are heterogeneous and multifaceted.Early detection is still a
基金supported by the National Natural Science Foundation of China(51878507)。
文摘The interface defeat phenomenon always occurs when a long-rod projectile impacting on the ceramic target with certain velocity,i.e.,the projectile is forced to flow radially on the surface of ceramic plates for a period of time without significant penetration.Interface defeat has a direct effect upon the ballistic performance of the armor piercing projectile,which is studied numerically and theoretically at present.Firstly,by modeling the projectiles and ceramic targets with the SPH(Smoothed Particle Hydrodynamics)particles and Lagrange finite elements,the systematic numerical simulations on interface defeat are performed with the commercial finite element program AUTODYN.Three different responses,i.e.,complete interface defeat,dwell and direct penetration,are reproduced in different types of ceramic targets(bare,buffered,radially confined and oblique).Furthermore,by adopting the validated numerical algorithms,constitutive models and the corresponding material parameters,the influences of projectile(material,diameter,nose shape),constitutive models of ceramic(JH-1 and JH-2 models),buffer and cover plate(thickness,constraints,material),as well as the prestress acted on the target(radial and hydrostatic) on the interface defeat(transition velocity and dwell time) are syste matically investigated.Finally,based on the energy conservation approach and taking the strain rate effect of ceramic material into account,a modified model for predicting the upper limit of transition velocity is proposed and validated.The present work and derived conclusions can provide helpful reference for the design and optimization of both the long-rod projectile and ceramic armor.
