Objective Long noncoding RNAs(lncRNAs)and microRNAs(miRNAs)are widely expressed in the brain and are associated with the development of neurological and neurodegenerative diseases.However,their roles and molecular mec...Objective Long noncoding RNAs(lncRNAs)and microRNAs(miRNAs)are widely expressed in the brain and are associated with the development of neurological and neurodegenerative diseases.However,their roles and molecular mechanisms in major depressive disorder(MDD)remain largely unknown.This study aimed to identify lncRNAs and miRNAs involved in the development of MDD and elucidate their molecular mechanisms.Methods Transcriptome and bioinformatic analyses were performed to identify miRNAs and lncRNAs related to MDD.C57 mice were subjected to chronic unpredictable mild stress(CUMS)to establish a depression model.Lentiviruses containing either lncRNA NPTN-IT1-201 or miR-142-5p were microinjected into the hippocampal region of these mice.Behavioral tests including the sucrose preference test(SPT),tail suspension test(TST),and forced swim test(FST)were conducted to evaluate depressive-like behaviors.Results The results revealed that overexpression of lncRNA NPTN-IT1-201 or inhibition of miR-142-5p significantly ameliorated depressive-like behaviors in CUMS-treated mice.Dual-luciferase reporter assays confirmed interactions between miR-142-5p with both brain-derived neurotrophic factor(BDNF)and NPTN-IT1-201.ELISA analysis revealed significant alterations in relevant biomarkers in the blood samples of MDD patients compared to healthy controls.Histological analyses,including HE and Nissl staining,showed marked structural changes in brain tissues following CUMS treatment,which were partially reversed by lncRNA NPTN-IT1-201 overexpression or miR-142-5p inhibition.Immunofluorescence imaging demonstrated significant differences in the levels of BAX,Bcl2,p65,Iba1 among different treatment groups.TUNEL assays confirmed reduced apoptosis in brain tissues following these interventions.Western blotting showed the significant differences in BDNF,BAX,and Bcl2 protein levels among different treatment groups.Conclusion NPTN-IT1-201 regulates inflammation and apoptosis in MDD by targeting BDNF via miR-142-5p,making it a potential therapeutic target for MDD.展开更多
Low salt intake is associated with depression, but the experimental evidence is not clear. Sixty adult mice were randomly divided into four groups (mild, moderate and severe salt deficiency groups and control) during ...Low salt intake is associated with depression, but the experimental evidence is not clear. Sixty adult mice were randomly divided into four groups (mild, moderate and severe salt deficiency groups and control) during the seasonal splitting from winter to spring. The mice in the control group were fed with standard ordinary diet (salt content 0.26%), while in the mild, moderate and severe groups, the mice were fed with 10%, 30% and 50% salt deficient feedstuff, lasting for approximately 3 months. The results showed that the salt content of feed was negatively correlated with the food intake and body weight of mice. The sucrose preference test found that only the mild salt deficiency group had no differ-ence between the beginning and the end of the experiment, and the other three groups in-cluding the control, showed a significant decrease. These results suggest that dietary salt content has an impact on the food intake and body weight of mice and is associated with the emergence of depressive-like behavior. Furthermore, the seasonal splitting from winter to spring may also have a differential synergistic effect on the change of depression-like behavior associated with low salt intake in mice.展开更多
The main objective of this work was to 1) study the influence of endogenous melatonin (Mel) abolishment via pinealectomy and 2) explore exogenous Mel effect on anxiety-like and depressive-like behavior in male and fem...The main objective of this work was to 1) study the influence of endogenous melatonin (Mel) abolishment via pinealectomy and 2) explore exogenous Mel effect on anxiety-like and depressive-like behavior in male and female rats. Rats were shamoperated (Sh) or pinealectomized (Px) and following subgroups were selected 1) Px/NaCl (0.9%) and Sh/NaCl (0.9%) : rats injected subcutaneously, once daily for 8 weeks, with saline solution NaCl (0.9%) as vehicle;2) Px/Mel (4 mg/Kg) and Sh/Mel (4 mg/Kg): Rats similarly injected with 4 mg/Kg of Mel. All animals were housed under a photoperiod of (LD:16/8). After different treatments animals were tested in the open-field test (OFT), elevated plus maze test (EPM) to determine anxiety-like behavior, and forced swimming test (FST) to evaluate depressive-like level. Our results revealed that level of anxiety-like and depressive-like behavior are significantly higher in Px/NaCl (0.9%) when compared to Sh/NaCl (0.9%) group, suggesting that pinelectomy induced an anxiogenic and depressant effects. The Px effects would be due to the absence of endogenous Mel synthesis and release. Additionally, we clearly demonstrated that the level of anxiety-like and depressive-like behavior are higher in Px/Mel (4 mg/Kg) and Sh/Mel when compared respectively to Px/NaCl (4 mg/Kg) and Sh/NaCl groups suggesting an anxiolytic and antidepressant effects of exogenous Mel. Behavioral responses were sex dependent since the difference between females and males, especially, after melatonin administration, were statistically significant. These experiments provide evidence that pinealectomy and Mel regulated emotionally behavior in male and female rats.展开更多
Aim To investigate the mechanisms underlying depressive-like behavior induced by chronic cerebral is- chemia in rats. Methods In the present study, a chronic cerebral hypoperfusion model was established by perma- 2VO...Aim To investigate the mechanisms underlying depressive-like behavior induced by chronic cerebral is- chemia in rats. Methods In the present study, a chronic cerebral hypoperfusion model was established by perma- 2VO） in rats. Two weeks after 2VO, GAB- nent bilateral common carotid arteries occlusion （two-vessel occlusion, AB receptor agonist baclofen （25 mg · kg^-1 . d^-1 i p ） was administrated for 21 days. The FST was performed to evaluate depressive-like behavior in which the immobility time was recorded. In addition, the expression of brain derived neurotrophic factor （BDNF） in hippocampal CA1 was measured by Western blot. Results The immobility time of 2VO group was significantly prolonged and the expression of BDNF was decreased by 28.95% compared with sham group. After activation of GABAB receptors by baclofen, the immobility time was significantly reduced and the expression of BDNF was increased by 47.91% compared with 2VO group. Conclusion 2VO induced ob- vious depressive-like behavior in rats. Activation of GABAB receptors alleviates the depressive-like behavior in- duced by chronic cerebral ischemia via upredulation of BDNF in hippocampal CA1 in rats.展开更多
OBJECTIVEα-Dstroglycan(α-DG)is a predominant component in the dystrophin-glycoprotein complex(DGC)and a recently char⁃acterized receptor for several extracellular matrix components with high affinity.Recent research...OBJECTIVEα-Dstroglycan(α-DG)is a predominant component in the dystrophin-glycoprotein complex(DGC)and a recently char⁃acterized receptor for several extracellular matrix components with high affinity.Recent research⁃es have reported that hypoglycosylation ofα-DG is associated with the pathophysiology of diseas⁃es,especially muscular dystrophy,but little is known about major depressive disorder(MDD).Like-acetylglucosaminyl transferase(Large)is a key enzyme for glycosylation ofα-DG,which mainly modifies two points in the middle domain ofα-DG:Thr-317 and Thr-319.Glycosylatedα-DG(GLY-α-DG)can bind with high affinity to extracellular matrix(ECM)molecules that con⁃tain laminin globular(LG)domains,including per⁃lecan,agrin and neurexin.Agrin is mainly derived from neurons rather than glial cells.In cultured hippocampal neurons,it was found that agrin could regulate the homeostatic plasticity of inhibi⁃tory neurons by acting on GLY-α-DG.Mdx mice are transgenetic models for the investigation of Duchenne muscular dystrophy.Many studies have shown that the expression of GLY-α-DG in the peripheral and brain tissues of Mdx mice is significantly down-regulated.Mdx mice show cognitive impairment and high levels of anxiety.In this study,we employed chronic social defeat stress(CSDS)to establish an animal model of depression and detected the expression of GLY-α-DG among the brain areas associated with the pathophysiology of depression.METHODS So⁃cial interaction test(SIT)and sucrose preference test(SPT)were used to evaluate depressive-like behavior.Open field(OF)and elevated plus maze(EPM)test were used to determine the anxiety-like behavior of Mdx mice.Novelty-sup⁃pressed feeding test(NSFT)forced swim test(FST)and tail suspension test(TST)were used to detect the depressive-like behavior of Mdx mice.Novel object recognition test(NOR)was applied to evaluate the cognition of Mdx mice.Subthreshold social defeat stress was used to explore the susceptibility to stress in Mdx mice.Stereotactic infusion of agrin into the ventral hippocampus(vHip),FST and TST were used to investigate the antidepressant effects of agrin.Adeno-associated virus(AAV)-mediated overex⁃pression techniques,behavior tests and whole-cell path-clamp technique were conducted to determine the impact of Large overexpression on CSDS susceptible mice.RESULTS The expres⁃sion ofα-DG and GLY-α-DG were significantly decreased in the vHip of CSDS susceptible mice.Mdx mice showed decreased expression of GLY-α-DG and increased anxiety-like behav⁃iors.Mdx mice displayed some depressive-like behaviors,and the susceptibility to stress was significantly increased.Downregulation of the expressionα-DG in the vHip by lentivirus increased the susceptibility to stress.Administra⁃tion of agrin to CSDS susceptible mice exerted antidepressant effects,and this effect could par⁃tially sustain for a week.The expression of Large was decreased in vHip.Overexpression of Large through AAV-Large reversed the depressive-like behaviors and restored the decreased frequency and amplitude of mIPSC.CONCLUSION GLY-α-DG and its glycosylase are significantly decreased in CSDS susceptible mice.Adminis⁃tration of agrin and overexpression of Large displays antidepressant effect,which may be related to its promotion of inhibitory synaptic transmission.展开更多
OBJECTIVE Alcohol dependence is not only the most common public health prob⁃lem worldwide,but also the cause of many alco⁃hol-related diseases,such as anxiety and depres⁃sion.However,the mechanism of these comor⁃bidit...OBJECTIVE Alcohol dependence is not only the most common public health prob⁃lem worldwide,but also the cause of many alco⁃hol-related diseases,such as anxiety and depres⁃sion.However,the mechanism of these comor⁃bidities is not clear.Recently,the role of phos⁃phodiesterases(PDEs)in anxiety-and depres⁃sion-like behavior induced by alcohol withdrawal has received increasing attentions.PDEs are a superfamily of enzymes that catalyze the hydroly⁃sis of intracellular cyclic AMP(cAMP)and(or)cyclic GMP(cGMP).There are 11 families(PDE1-PDE11),each of which has 1 to 4 sub⁃types encoded by different genes.In the present study,we identified the key PDEs involved in anxiety-and depression-like behavior induced by alcohol withdrawal.METHODS After withdrawal from short-term or chronic intermittent ethanol vapor exposure(STEVE and CIEVE,respectively),adult male C57BL/6J(B6)mice were tested for anxiety-and depression-like behavior using the sucrose preference,open field,elevated plus-maze,tail suspension,forced swimming,hole board and light-dark tests.In addition,the expression of PDE subtypes(PDE2,PDE4,and PDE7)in the hippocampus,amygdala,and stria⁃tum,which are considered as anxiety-and(or)depression-related brain regions,was detected by Western blotting.RESULTS①Differences in anxiety-and depression-like behaviors between STEVE and CIEVE mice.Compared to STEVE mice,CIEVE mice showed greater anxiety-and depression-like behavior in the tests described above.②The expression of PDE2,PDE4 and PDE7 in the anxiety-and depression-related brain regions of CIEVE mice.Compared to the STEVE mice,CIEVE mice showed significant higher expression of PDE4A and PDE7A in the hippo⁃campus(P<0.05)and PDE4D and PDE7A in the amygdala(P<0.05).However,the expres⁃sion of PDE2A,PDE4B,PDE4D and PDE7B in the hippocampus,PDE2A,PDE4A,PDE4B and PDE7B in the amygdala,PDE2A,PDE4A,PDE4B,PDE4D,PDE7A and PDE7B in the striatum was not significantly changed.CONCLUSION The model of CIEVE showed significant anxiety-and depression-like behavior,with concurrent increases in the expression of PDE4A and PDE7A in the hippocampus and PDE4D and PDE7A in the amygdala.These results suggest that PDE4A,PDE4D,and DE7A may play an important role in the regulation of anxiety-and depression-like behavior induced by alcohol withdrawal.展开更多
Olive flounder(Paralichthys olivaceus),a marine demersal flatfish species,exhibits obvious timid and depressive-like characteristics.Adult olive flounder bury themselves in the sand and present motionless behavior.How...Olive flounder(Paralichthys olivaceus),a marine demersal flatfish species,exhibits obvious timid and depressive-like characteristics.Adult olive flounder bury themselves in the sand and present motionless behavior.However,the detail mechanism of regulating the motionless behavior is not fully understood.In this study,using adult group(AG)and juvenile group(JG)flounder as a model,we compared the locomotor activity of AG and JG flounder,and analyzed the transcriptomic expression profiles in the spinal cord by RNA-seq methods.The behavioral experiment showed that AG flounder displayed lower locomotor activity.Transcriptome analysis found a total of 1711 significantly differential expressed genes(DEGs),among which 818 genes were up-regulated and 893 genes were down-regulated in AG flounder compared with JG flounder.Specifically,locomotor behavior related genes(parvalbumin,urotensin Ⅱ and creatine kinase)were down-regulated.Meanwhile glial fibrillary acidic protein,the biomarkers of astroglial pathology,and glutamatergic synaptic genes were significantly up-regulated in AG flounder.In addition,Gene Ontology(GO)enrichment analysis revealed that DEGs enriched in peptide biosynthetic process,translation procession were down-regulated in the AG flounder.The Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway analysis revealed that ribosome,oxidative phosphorylation and glutamatergic synapse pathway were over-represented.After treatment with antagonist of glutamate receptor LY341495,flounder more often swam out of the sand and displayed significantly more off-bottom swimming behavior,suggesting the anti-depressive effect of LY341495.Taken together,in combination with behavioral tests and transcriptomic analyses,we conclude that the glutamate receptor in spinal cord plays an important role in timid and depressive-like behavior in flounder.展开更多
Short-chain fatty acids(SCFAs)have been increasingly evidenced to be important bioactive metabolites of the gut microbiota and transducers in controlling diverse psychiatric or neurological disorders via the microbiot...Short-chain fatty acids(SCFAs)have been increasingly evidenced to be important bioactive metabolites of the gut microbiota and transducers in controlling diverse psychiatric or neurological disorders via the microbiota-gut-brain axis.However,the precise mechanism by which brain SCFAs extert multiple beneficial effects is not completely understood.Our previous research has demonstrated that the acetyl-coenzyme A synthetase short-chain family member 2(ACSS2)is a novel target of the rapid and long-lasting antidepressant responses.Here,we show that micromolar SCFAs significantly augment both total cellular and nuclear ACSS2 to trigger tryptophan hydroxylase 2(TPH2)promoter histone acetylation and its transcription in SH-SY5Y cells.In chronic-restraint-stress-induced depression mice,neuronal ACSS2 knockdown by stereotaxic injection of adeno-associated virus in the hippocampus abolished SCFA-mediated improvements in depressive-like behaviors of mice,supporting that ACSS2 is required for SCFA-mediated antidepressant responses.Mechanistically,the peroxisome-proliferator-activated receptor gamma(PPARγ)is identified as a novel partner of ACSS2 to activate TPH2 transcription.Importantly,PPARγis also responsible for SCFA-mediated antidepressant-like effects via ACSS2-TPH2 axis.To further support brain SCFAs as a therapeutic target for antidepressant effects,d-mannose,which is a naturally present hexose,can significantly reverse the dysbiosis of gut microbiota in the chronic-restraint-stress-exposure mice and augment brain SCFAs to protect against the depressive-like behaviors via ACSS2-PPARγ-TPH2 axis.In summary,brain SCFAs can activate ACSS2-PPARγ-TPH2 axis to play the antidepressive-like effects,and d-mannose is suggested to be an inducer of brain SCFAs in resisting depression.展开更多
Objective:This study aimed to examine the reliability and validity of the Chinese version of the Behavioral Inhibition System/Behavioral Activation System(BIS/BAS)scales among stroke survivors.Methods:The cross-sectio...Objective:This study aimed to examine the reliability and validity of the Chinese version of the Behavioral Inhibition System/Behavioral Activation System(BIS/BAS)scales among stroke survivors.Methods:The cross-sectional study was conducted at four comprehensive hospitals in Taizhou,Jiangsu,China.A sample of 232 first-ever stroke survivors were recruited from June to August 2023.Validity was examined using face validity and construct validity,which used confirmatory factor analysis(CFA)and known-group analysis.Reliability was evaluated by internal consistency and test-retest reliability.Results:The BIS/BAS scales demonstrated satisfactory face validity.The findings of CFAs supported the original four-factor structure of BAS-reward,BAS-drive,BAS-fun seeking,and BIS with acceptable model fit indices.Discriminative validity,assessed via known-group analysis,indicated that stroke survivors with probable depression had significantly lower mean BAS-reward,BAS-drive,and BAS-fun seeking scores(P<0.001)and a higher mean BIS score(P=0.028)compared to those without probable depression.The internal consistency,measured by Cronbach’s a coefficients for the subscales,ranged from 0.669 to 0.964.Test-retest reliability,assessed using intra-class correlation coefficients,ranged from 0.61 to 0.93.Conclusions:The Chinese version of the BIS/BAS scales could be a reliable and valid instrument for measuring behavioral activation among stroke survivors.展开更多
Since the pioneering work by Broca and Wernicke in the 19th century,who examined individuals with brain lesions to associate them with specific behaviors,it was evident that behaviors are complex and cannot be fully a...Since the pioneering work by Broca and Wernicke in the 19th century,who examined individuals with brain lesions to associate them with specific behaviors,it was evident that behaviors are complex and cannot be fully attributable to specific brain areas alone.Instead,they involve connectivity among brain areas,whether close or distant.At that time,this approach was considered the optimal way to dissect brain circuitry and function.These pioneering efforts opened the field to explore the necessity or sufficiency of brain areas in controlling behavior and hence dissecting brain function.However,the connectivity of the brain and the mechanisms through which various brain regions regulate specific behaviors,either individually or collaboratively,remain largely elusive.Utilizing animal models,researchers have endeavored to unravel the necessity or sufficiency of specific brain areas in influencing behavior;however,no clear associations have been firmly established.展开更多
Magnesium matrix composites with both high strength and ductility have been achieved by introducing pure Ti particles.However,the properties of the surfaces of the composites need to be improved by surface technology,...Magnesium matrix composites with both high strength and ductility have been achieved by introducing pure Ti particles.However,the properties of the surfaces of the composites need to be improved by surface technology,such as micro-arc oxidation(MAO).In this study,we investigated the influence of the Ti-reinforcement phase on coating growth and evolution by subjecting both AZ91 alloy and AZ91/Ti composite to MAO treatment using silicate-based and phosphate-based electrolytes.Results revealed that the Ti-reinforcement phase influenced the MAO process,altering discharge behavior,and leading to a decreased cell voltage.The vigorous discharge of the Ti-reinforcement phase induced the formation of coating discharge channels,concurrently dissolving and oxidizing Ti-reinforcement to produce a composite ceramic coating with TiO2.The MAO coating on the AZ91/Ti composite exhibited a dark blue macromorphology and distinctive local micromorphological anomalies.In silicate electrolyte,a“volcano-like”localized morphology centered on the discharge channel emerged.In contrast,treatment in phosphate-based electrolyte resulted in a coating morphology similar to typical porous ceramic coatings,with visible radial discharge micropores at the reinforcement phase location.Compared to the AZ91 alloy,the coating on the AZ91/Ti composite exhibited lower thickness and higher porosity.MAO treatment reduced the self-corrosion current density of the AZ91/Ti surface by two orders of magnitude.The silicate coating demonstrated better corrosion resistance than the phosphate coating,attributed to its lower porosity.The formation mechanism of MAO coatings on AZ91/Ti composites in phosphate-based and silicate-based electrolytes was proposed.展开更多
The performance of Mg alloys is significantly influenced by the concentrations and solid solution behavior of the alloying elements.In this work,the solid solution behavior of 20 alloying elements in 190 ternary Mg al...The performance of Mg alloys is significantly influenced by the concentrations and solid solution behavior of the alloying elements.In this work,the solid solution behavior of 20 alloying elements in 190 ternary Mg alloy systems at 500℃are systematically investigated.The solid solution behavior of a set of two different alloying elements in Mg alloy systems are suggested to be classified into three categories:inclusivity,exclusivity and proportionality.Inclusivity classification indicates that the two alloying elements are inclusive inα-Mg,increasing the joint solubility of both elements.Exclusivity classification suggests that the two alloying elements have a low joint solid solubility inα-Mg,since they prefer to form stable second phases.For the proportionality classification,the solubility curve of the ternary Mg alloy systems is a straight line connecting the solubility points of the two sub-binary systems.The proposed classification theory was validated by key experiments and the calculation of formation energies.The interaction effects between alloying elements and the preference of formation of second phases are the main factors determining the solid solution behavior classifications.Based on the observed solid solution features of multi-component Mg alloys,principles for alloy design of different types of high-performance Mg alloys were proposed in this work.展开更多
Efficient lubrication of magnesium alloys is a highly challenging topic in the field of tribology.In this study,magnesium silicate hydroxide(MSH)nanotubes with serpentine structures were synthesized.The tribological b...Efficient lubrication of magnesium alloys is a highly challenging topic in the field of tribology.In this study,magnesium silicate hydroxide(MSH)nanotubes with serpentine structures were synthesized.The tribological behavior of AZ91D magnesium alloy rubbed against GCr15 steel was studied under lubricating oil with surface-modified MSH nanotubes as additives.The effects of the concentration,applied load,and reciprocating frequency on the friction and wear of the AZ91D alloy were studied using an SRV-4 sliding wear tester.Results show a decrease of 18.7–68.5%in friction coefficient,and a reduction of 19.4–54.3%in wear volume of magnesium alloy can be achieved by applying the synthetic serpentine additive under different conditions.A suspension containing 0.3 wt.%MSH was most efficient in reducing wear and friction.High frequency and medium load were more conducive to improving the tribological properties of magnesium alloys.A series of beneficial physical and chemical processes occurring at the AZ91D alloy/steel interface can be used to explain friction and wear reduction based on the characterization of the morphology,chemical composition,chemical state,microstructure,and nanomechanical properties of the worn surface.The synthetic MSH,with serpentine structure and nanotube morphology,possesses excellent adsorbability,high chemical activity,and good self-lubrication and catalytic activity.Therefore,physical polishing,tribochemical reactions,and physicalchemical depositions can occur easily on the sliding contacts.A dense tribolayer with a complex composition and composite structure was formed on the worn surface.Its high hardness,good toughness and plasticity,and prominent lubricity resulted in the improvement of friction and wear,making the synthetic MSH a promising efficient oil additive for magnesium alloys under boundary and mixed lubrication.展开更多
This study aims to explore the characteristics of novice teachers’inappropriate behaviors in classroom teaching and their intervention strategies.With the continuous improvement of education quality,novice teachers f...This study aims to explore the characteristics of novice teachers’inappropriate behaviors in classroom teaching and their intervention strategies.With the continuous improvement of education quality,novice teachers face increasing challenges in teaching practice.Their inappropriate behaviors not only affect the classroom atmosphere but may also negatively impact students’learning outcomes.Therefore,researching the characteristics of novice teachers’inappropriate behaviors and their intervention strategies holds significant scientific and social value.This study employs a combination of quantitative and qualitative methods to analyze the behavioral patterns of novice teachers in classroom teaching and proposes corresponding intervention strategies.The results indicate that novice teachers’inappropriate behaviors mainly manifest as poor classroom management,monotonous teaching methods,and insufficient interaction with students.Based on these findings,the study proposes a series of effective intervention strategies,including enhancing teacher training,optimizing teaching design,and promoting positive interactions between teachers and students.The conclusions of the study not only provide practical guidance for educational practice but also point out directions for future research,emphasizing the crucial role of teacher professional development in improving teaching quality.展开更多
The pre-weld heat treatment was carried out to obtain different initial microstructures of the GH4169 superalloy,and then Linear Friction Welding(LFW)was performed.The effect of the pre-weld heat treatment on the micr...The pre-weld heat treatment was carried out to obtain different initial microstructures of the GH4169 superalloy,and then Linear Friction Welding(LFW)was performed.The effect of the pre-weld heat treatment on the microstructure evolution and mechanical properties of the joint was analyzed,and the joint electrochemical corrosion behavior as well as the hot corrosion behavior was studied.The results show that the joint hardness of Base Metal(BM)increases after pre-weld heat treatment,and the strengthening phasesγ′andγ″further precipitate.However,the precipitation phases dissolve significantly in the Weld Zone(WZ)due to the thermal process of LFW.The corrosion resistance in BM is reduced after the pre-weld heat treatment,while it is similar in WZ with a slight decrease.The surface morphology of the BM and WZ can be generally divided into a loose and porous matrix and a scattered oxide particle layer after hot corrosion.The joint cross section exhibits a Cr-depleted zone with the diffusion of Cr to form an oxide film.The corrosion product mainly consists of Fe_(2)O_(3)/Fe_(3)O_(4) as the outer layer and Cr_(2)O_(3) as the inner layer.展开更多
The undrained mechanical behavior of unsaturated completely weathered granite(CWG)is highly susceptible to alterations in the hydraulic environment,particularly under uniaxial loading conditions,due to the unique natu...The undrained mechanical behavior of unsaturated completely weathered granite(CWG)is highly susceptible to alterations in the hydraulic environment,particularly under uniaxial loading conditions,due to the unique nature of this soil type.In this study,a series of unconfined compression tests were carried out on unsaturated CWG soil in an underground engineering site,and the effects of varying the environmental variables on the main undrained mechanical properties were analyzed.Based on the experimental results,a novel constitutive model was then established using the damage mechanics theory and the undetermined coefficient method.The results demonstrate that the curves of remolded CWG specimens with different moisture contents and dry densities exhibited diverse characteristics,including brittleness,significant softening,and ductility.As a typical indicator,the unconfined compression strength of soil specimens initially increased with an increase in moisture content and then decreased.Meanwhile,an optimal moisture content of approximately 10.5%could be observed,while a critical moisture content value of 13.0%was identified,beyond which the strength of the specimen decreases sharply.Moreover,the deformation and fracture of CWG specimens were predominantly caused by shear failure,and the ultimate failure modes were primarily influenced by moisture content rather than dry density.Furthermore,by comparing several similar models and the experimental data,the proposed model could accurately replicate the undrained mechanical characteristics of unsaturated CWG soil,and quantitatively describe the key mechanical indexes.These findings offer a valuable reference point for understanding the underlying mechanisms,anticipating potential risks,and implementing effective control measures in similar underground engineering projects.展开更多
Natural cemented calcareous sand and limestone are highly complex and not well understood in terms of the me-chanical behavior due to the difficulty of obtaining undisturbed samples from far sea.This paper proposes an...Natural cemented calcareous sand and limestone are highly complex and not well understood in terms of the me-chanical behavior due to the difficulty of obtaining undisturbed samples from far sea.This paper proposes an artificial method in a laboratory setting using microbial-induced carbonate precipitation(MICP)to simulate the natural process of cementation of limestone.The artificially cemented sand has a high degree of similarity with the natural weakly limestone in three aspects:(1)the mineral composition of the cemented material is also granular calcite and acicular aragonite;(2)the microstructure in interconnected open pore network can be gradually closed and contracted with cementation.The porosity reaches to approximately 9.2%;(3)both the stress-strain relationship and the unconfined strength closely resemble that of natural weakly limestone.Furthermore,both static and dynamic behaviors of artificial limestone were studied by quasi-static compression tests and Split Hopkinson Pressure Bar(SHPB)tests,finding that the unconfined strength of weakly artifical limestone exponentially increases with increasing strain rate.A rate-dependent bond strength was proposed and implemented in software to reveal the mechanism of strain rate effects.It is found that the loading velocity is too high to keep in sync with the initiation and propagation of cracks under impact loading.This delay-induced viscosity may restrict the movement of the surrounding balls,thus increasing resistance.展开更多
The influence of Nb-V microalloying on the hot deformation behavior and microstructures of medium Mn steel(MMS)was investigated by uniaxial hot compression tests.By establishing the constitutive equations for simulati...The influence of Nb-V microalloying on the hot deformation behavior and microstructures of medium Mn steel(MMS)was investigated by uniaxial hot compression tests.By establishing the constitutive equations for simulating the measured flow curves,we successfully constructed deformation activation energy(Q)maps and processing maps for identifying the region of flow instability.We concluded the following consequences of Nb-V alloying for MMS.(i)The critical strain increases and the increment diminishes with the increasing deformation temperature,suggesting that NbC precipitates more efficiently retard dynamic recrystallization(DRX)in MMS compared with solute Nb.(ii)The deformation activation energy of MMS is significantly increased and even higher than that of some reported high Mn steels,suggesting that its ability to retard DRX is greater than that of the high Mn content.(iii)The hot workability of MMS is improved by narrowing the hot processing window for the unstable flow stress,in which fine recrystallized and coarse unrecrystallized grains are present.展开更多
Type 2 diabetes(T2D)is an insidious disease associated with neural and vascular complications,acceleration of cardiovascular disease,changes in heart function,and premature death.In the newly released article of the J...Type 2 diabetes(T2D)is an insidious disease associated with neural and vascular complications,acceleration of cardiovascular disease,changes in heart function,and premature death.In the newly released article of the Journal of Sport and Health Science,Liang et al.1 describe results from the UK Biobank data showing the benefits of moderate-to-vigorous intensity physical activity(MVPA)on reducing the risks for vascular events in 11,474 adults with T2D and prediabetes.展开更多
The ongoing revolution in information technology is reshaping human life. In the realm of health behavior, wearable technology emerges as a leading digital solution,capturing physical behaviors (i.e., physical activit...The ongoing revolution in information technology is reshaping human life. In the realm of health behavior, wearable technology emerges as a leading digital solution,capturing physical behaviors (i.e., physical activity, sedentary habits, sleep patterns) within the 24-h cycle of daily life. Wearables are applied in research, clinical practice, and as lifestyle devices;most obvious, they promise to be a key element for increasing human physical activity, one of the biggest health challenges nowadays.展开更多
基金supported by grants from the National Natural Science Foundation of China(No.82160311,No.82160225 and No.82060232)the Science and Technology Fund Project of Guizhou Health and Health Commission(No.gzwkj2021-356)+1 种基金Basic Science Technology Project of Guizhou Province[No.ZK(2021)412]the Special Project of Academic New Seedling Cultivation and Free Exploration Innovation-Post-project subsidy of the National Natural Science Foundation of China,“Thousand Levels”of Guizhou Province High Level Innovative Talents(No.gzwjrs 2023-012).
文摘Objective Long noncoding RNAs(lncRNAs)and microRNAs(miRNAs)are widely expressed in the brain and are associated with the development of neurological and neurodegenerative diseases.However,their roles and molecular mechanisms in major depressive disorder(MDD)remain largely unknown.This study aimed to identify lncRNAs and miRNAs involved in the development of MDD and elucidate their molecular mechanisms.Methods Transcriptome and bioinformatic analyses were performed to identify miRNAs and lncRNAs related to MDD.C57 mice were subjected to chronic unpredictable mild stress(CUMS)to establish a depression model.Lentiviruses containing either lncRNA NPTN-IT1-201 or miR-142-5p were microinjected into the hippocampal region of these mice.Behavioral tests including the sucrose preference test(SPT),tail suspension test(TST),and forced swim test(FST)were conducted to evaluate depressive-like behaviors.Results The results revealed that overexpression of lncRNA NPTN-IT1-201 or inhibition of miR-142-5p significantly ameliorated depressive-like behaviors in CUMS-treated mice.Dual-luciferase reporter assays confirmed interactions between miR-142-5p with both brain-derived neurotrophic factor(BDNF)and NPTN-IT1-201.ELISA analysis revealed significant alterations in relevant biomarkers in the blood samples of MDD patients compared to healthy controls.Histological analyses,including HE and Nissl staining,showed marked structural changes in brain tissues following CUMS treatment,which were partially reversed by lncRNA NPTN-IT1-201 overexpression or miR-142-5p inhibition.Immunofluorescence imaging demonstrated significant differences in the levels of BAX,Bcl2,p65,Iba1 among different treatment groups.TUNEL assays confirmed reduced apoptosis in brain tissues following these interventions.Western blotting showed the significant differences in BDNF,BAX,and Bcl2 protein levels among different treatment groups.Conclusion NPTN-IT1-201 regulates inflammation and apoptosis in MDD by targeting BDNF via miR-142-5p,making it a potential therapeutic target for MDD.
文摘Low salt intake is associated with depression, but the experimental evidence is not clear. Sixty adult mice were randomly divided into four groups (mild, moderate and severe salt deficiency groups and control) during the seasonal splitting from winter to spring. The mice in the control group were fed with standard ordinary diet (salt content 0.26%), while in the mild, moderate and severe groups, the mice were fed with 10%, 30% and 50% salt deficient feedstuff, lasting for approximately 3 months. The results showed that the salt content of feed was negatively correlated with the food intake and body weight of mice. The sucrose preference test found that only the mild salt deficiency group had no differ-ence between the beginning and the end of the experiment, and the other three groups in-cluding the control, showed a significant decrease. These results suggest that dietary salt content has an impact on the food intake and body weight of mice and is associated with the emergence of depressive-like behavior. Furthermore, the seasonal splitting from winter to spring may also have a differential synergistic effect on the change of depression-like behavior associated with low salt intake in mice.
文摘The main objective of this work was to 1) study the influence of endogenous melatonin (Mel) abolishment via pinealectomy and 2) explore exogenous Mel effect on anxiety-like and depressive-like behavior in male and female rats. Rats were shamoperated (Sh) or pinealectomized (Px) and following subgroups were selected 1) Px/NaCl (0.9%) and Sh/NaCl (0.9%) : rats injected subcutaneously, once daily for 8 weeks, with saline solution NaCl (0.9%) as vehicle;2) Px/Mel (4 mg/Kg) and Sh/Mel (4 mg/Kg): Rats similarly injected with 4 mg/Kg of Mel. All animals were housed under a photoperiod of (LD:16/8). After different treatments animals were tested in the open-field test (OFT), elevated plus maze test (EPM) to determine anxiety-like behavior, and forced swimming test (FST) to evaluate depressive-like level. Our results revealed that level of anxiety-like and depressive-like behavior are significantly higher in Px/NaCl (0.9%) when compared to Sh/NaCl (0.9%) group, suggesting that pinelectomy induced an anxiogenic and depressant effects. The Px effects would be due to the absence of endogenous Mel synthesis and release. Additionally, we clearly demonstrated that the level of anxiety-like and depressive-like behavior are higher in Px/Mel (4 mg/Kg) and Sh/Mel when compared respectively to Px/NaCl (4 mg/Kg) and Sh/NaCl groups suggesting an anxiolytic and antidepressant effects of exogenous Mel. Behavioral responses were sex dependent since the difference between females and males, especially, after melatonin administration, were statistically significant. These experiments provide evidence that pinealectomy and Mel regulated emotionally behavior in male and female rats.
文摘Aim To investigate the mechanisms underlying depressive-like behavior induced by chronic cerebral is- chemia in rats. Methods In the present study, a chronic cerebral hypoperfusion model was established by perma- 2VO） in rats. Two weeks after 2VO, GAB- nent bilateral common carotid arteries occlusion （two-vessel occlusion, AB receptor agonist baclofen （25 mg · kg^-1 . d^-1 i p ） was administrated for 21 days. The FST was performed to evaluate depressive-like behavior in which the immobility time was recorded. In addition, the expression of brain derived neurotrophic factor （BDNF） in hippocampal CA1 was measured by Western blot. Results The immobility time of 2VO group was significantly prolonged and the expression of BDNF was decreased by 28.95% compared with sham group. After activation of GABAB receptors by baclofen, the immobility time was significantly reduced and the expression of BDNF was increased by 47.91% compared with 2VO group. Conclusion 2VO induced ob- vious depressive-like behavior in rats. Activation of GABAB receptors alleviates the depressive-like behavior in- duced by chronic cerebral ischemia via upredulation of BDNF in hippocampal CA1 in rats.
文摘OBJECTIVEα-Dstroglycan(α-DG)is a predominant component in the dystrophin-glycoprotein complex(DGC)and a recently char⁃acterized receptor for several extracellular matrix components with high affinity.Recent research⁃es have reported that hypoglycosylation ofα-DG is associated with the pathophysiology of diseas⁃es,especially muscular dystrophy,but little is known about major depressive disorder(MDD).Like-acetylglucosaminyl transferase(Large)is a key enzyme for glycosylation ofα-DG,which mainly modifies two points in the middle domain ofα-DG:Thr-317 and Thr-319.Glycosylatedα-DG(GLY-α-DG)can bind with high affinity to extracellular matrix(ECM)molecules that con⁃tain laminin globular(LG)domains,including per⁃lecan,agrin and neurexin.Agrin is mainly derived from neurons rather than glial cells.In cultured hippocampal neurons,it was found that agrin could regulate the homeostatic plasticity of inhibi⁃tory neurons by acting on GLY-α-DG.Mdx mice are transgenetic models for the investigation of Duchenne muscular dystrophy.Many studies have shown that the expression of GLY-α-DG in the peripheral and brain tissues of Mdx mice is significantly down-regulated.Mdx mice show cognitive impairment and high levels of anxiety.In this study,we employed chronic social defeat stress(CSDS)to establish an animal model of depression and detected the expression of GLY-α-DG among the brain areas associated with the pathophysiology of depression.METHODS So⁃cial interaction test(SIT)and sucrose preference test(SPT)were used to evaluate depressive-like behavior.Open field(OF)and elevated plus maze(EPM)test were used to determine the anxiety-like behavior of Mdx mice.Novelty-sup⁃pressed feeding test(NSFT)forced swim test(FST)and tail suspension test(TST)were used to detect the depressive-like behavior of Mdx mice.Novel object recognition test(NOR)was applied to evaluate the cognition of Mdx mice.Subthreshold social defeat stress was used to explore the susceptibility to stress in Mdx mice.Stereotactic infusion of agrin into the ventral hippocampus(vHip),FST and TST were used to investigate the antidepressant effects of agrin.Adeno-associated virus(AAV)-mediated overex⁃pression techniques,behavior tests and whole-cell path-clamp technique were conducted to determine the impact of Large overexpression on CSDS susceptible mice.RESULTS The expres⁃sion ofα-DG and GLY-α-DG were significantly decreased in the vHip of CSDS susceptible mice.Mdx mice showed decreased expression of GLY-α-DG and increased anxiety-like behav⁃iors.Mdx mice displayed some depressive-like behaviors,and the susceptibility to stress was significantly increased.Downregulation of the expressionα-DG in the vHip by lentivirus increased the susceptibility to stress.Administra⁃tion of agrin to CSDS susceptible mice exerted antidepressant effects,and this effect could par⁃tially sustain for a week.The expression of Large was decreased in vHip.Overexpression of Large through AAV-Large reversed the depressive-like behaviors and restored the decreased frequency and amplitude of mIPSC.CONCLUSION GLY-α-DG and its glycosylase are significantly decreased in CSDS susceptible mice.Adminis⁃tration of agrin and overexpression of Large displays antidepressant effect,which may be related to its promotion of inhibitory synaptic transmission.
文摘OBJECTIVE Alcohol dependence is not only the most common public health prob⁃lem worldwide,but also the cause of many alco⁃hol-related diseases,such as anxiety and depres⁃sion.However,the mechanism of these comor⁃bidities is not clear.Recently,the role of phos⁃phodiesterases(PDEs)in anxiety-and depres⁃sion-like behavior induced by alcohol withdrawal has received increasing attentions.PDEs are a superfamily of enzymes that catalyze the hydroly⁃sis of intracellular cyclic AMP(cAMP)and(or)cyclic GMP(cGMP).There are 11 families(PDE1-PDE11),each of which has 1 to 4 sub⁃types encoded by different genes.In the present study,we identified the key PDEs involved in anxiety-and depression-like behavior induced by alcohol withdrawal.METHODS After withdrawal from short-term or chronic intermittent ethanol vapor exposure(STEVE and CIEVE,respectively),adult male C57BL/6J(B6)mice were tested for anxiety-and depression-like behavior using the sucrose preference,open field,elevated plus-maze,tail suspension,forced swimming,hole board and light-dark tests.In addition,the expression of PDE subtypes(PDE2,PDE4,and PDE7)in the hippocampus,amygdala,and stria⁃tum,which are considered as anxiety-and(or)depression-related brain regions,was detected by Western blotting.RESULTS①Differences in anxiety-and depression-like behaviors between STEVE and CIEVE mice.Compared to STEVE mice,CIEVE mice showed greater anxiety-and depression-like behavior in the tests described above.②The expression of PDE2,PDE4 and PDE7 in the anxiety-and depression-related brain regions of CIEVE mice.Compared to the STEVE mice,CIEVE mice showed significant higher expression of PDE4A and PDE7A in the hippo⁃campus(P<0.05)and PDE4D and PDE7A in the amygdala(P<0.05).However,the expres⁃sion of PDE2A,PDE4B,PDE4D and PDE7B in the hippocampus,PDE2A,PDE4A,PDE4B and PDE7B in the amygdala,PDE2A,PDE4A,PDE4B,PDE4D,PDE7A and PDE7B in the striatum was not significantly changed.CONCLUSION The model of CIEVE showed significant anxiety-and depression-like behavior,with concurrent increases in the expression of PDE4A and PDE7A in the hippocampus and PDE4D and PDE7A in the amygdala.These results suggest that PDE4A,PDE4D,and DE7A may play an important role in the regulation of anxiety-and depression-like behavior induced by alcohol withdrawal.
基金supported by grants from the National Natural Science Foundation of China(32273103).
文摘Olive flounder(Paralichthys olivaceus),a marine demersal flatfish species,exhibits obvious timid and depressive-like characteristics.Adult olive flounder bury themselves in the sand and present motionless behavior.However,the detail mechanism of regulating the motionless behavior is not fully understood.In this study,using adult group(AG)and juvenile group(JG)flounder as a model,we compared the locomotor activity of AG and JG flounder,and analyzed the transcriptomic expression profiles in the spinal cord by RNA-seq methods.The behavioral experiment showed that AG flounder displayed lower locomotor activity.Transcriptome analysis found a total of 1711 significantly differential expressed genes(DEGs),among which 818 genes were up-regulated and 893 genes were down-regulated in AG flounder compared with JG flounder.Specifically,locomotor behavior related genes(parvalbumin,urotensin Ⅱ and creatine kinase)were down-regulated.Meanwhile glial fibrillary acidic protein,the biomarkers of astroglial pathology,and glutamatergic synaptic genes were significantly up-regulated in AG flounder.In addition,Gene Ontology(GO)enrichment analysis revealed that DEGs enriched in peptide biosynthetic process,translation procession were down-regulated in the AG flounder.The Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway analysis revealed that ribosome,oxidative phosphorylation and glutamatergic synapse pathway were over-represented.After treatment with antagonist of glutamate receptor LY341495,flounder more often swam out of the sand and displayed significantly more off-bottom swimming behavior,suggesting the anti-depressive effect of LY341495.Taken together,in combination with behavioral tests and transcriptomic analyses,we conclude that the glutamate receptor in spinal cord plays an important role in timid and depressive-like behavior in flounder.
基金supported by the National Natural Science Foundation of China(82101606,82173105,81771775,81971471,and 32270800)Shandong Excellent Young Scientists Fund Program(Overseas)(2022HWYQ-028)Shandong Provincial Natural Science Foundation(ZR2022MC012).
文摘Short-chain fatty acids(SCFAs)have been increasingly evidenced to be important bioactive metabolites of the gut microbiota and transducers in controlling diverse psychiatric or neurological disorders via the microbiota-gut-brain axis.However,the precise mechanism by which brain SCFAs extert multiple beneficial effects is not completely understood.Our previous research has demonstrated that the acetyl-coenzyme A synthetase short-chain family member 2(ACSS2)is a novel target of the rapid and long-lasting antidepressant responses.Here,we show that micromolar SCFAs significantly augment both total cellular and nuclear ACSS2 to trigger tryptophan hydroxylase 2(TPH2)promoter histone acetylation and its transcription in SH-SY5Y cells.In chronic-restraint-stress-induced depression mice,neuronal ACSS2 knockdown by stereotaxic injection of adeno-associated virus in the hippocampus abolished SCFA-mediated improvements in depressive-like behaviors of mice,supporting that ACSS2 is required for SCFA-mediated antidepressant responses.Mechanistically,the peroxisome-proliferator-activated receptor gamma(PPARγ)is identified as a novel partner of ACSS2 to activate TPH2 transcription.Importantly,PPARγis also responsible for SCFA-mediated antidepressant-like effects via ACSS2-TPH2 axis.To further support brain SCFAs as a therapeutic target for antidepressant effects,d-mannose,which is a naturally present hexose,can significantly reverse the dysbiosis of gut microbiota in the chronic-restraint-stress-exposure mice and augment brain SCFAs to protect against the depressive-like behaviors via ACSS2-PPARγ-TPH2 axis.In summary,brain SCFAs can activate ACSS2-PPARγ-TPH2 axis to play the antidepressive-like effects,and d-mannose is suggested to be an inducer of brain SCFAs in resisting depression.
文摘Objective:This study aimed to examine the reliability and validity of the Chinese version of the Behavioral Inhibition System/Behavioral Activation System(BIS/BAS)scales among stroke survivors.Methods:The cross-sectional study was conducted at four comprehensive hospitals in Taizhou,Jiangsu,China.A sample of 232 first-ever stroke survivors were recruited from June to August 2023.Validity was examined using face validity and construct validity,which used confirmatory factor analysis(CFA)and known-group analysis.Reliability was evaluated by internal consistency and test-retest reliability.Results:The BIS/BAS scales demonstrated satisfactory face validity.The findings of CFAs supported the original four-factor structure of BAS-reward,BAS-drive,BAS-fun seeking,and BIS with acceptable model fit indices.Discriminative validity,assessed via known-group analysis,indicated that stroke survivors with probable depression had significantly lower mean BAS-reward,BAS-drive,and BAS-fun seeking scores(P<0.001)and a higher mean BIS score(P=0.028)compared to those without probable depression.The internal consistency,measured by Cronbach’s a coefficients for the subscales,ranged from 0.669 to 0.964.Test-retest reliability,assessed using intra-class correlation coefficients,ranged from 0.61 to 0.93.Conclusions:The Chinese version of the BIS/BAS scales could be a reliable and valid instrument for measuring behavioral activation among stroke survivors.
基金supported by ANID Fondecyt Iniciacion 11180540(to FJB)ANID PAI 77180077(to FJB)+2 种基金UNAB DI-02-22/REG(to FJB)Exploración-ANID 13220203(to FJB)ANID-MILENIO(NCN2023_23,to FJB)。
文摘Since the pioneering work by Broca and Wernicke in the 19th century,who examined individuals with brain lesions to associate them with specific behaviors,it was evident that behaviors are complex and cannot be fully attributable to specific brain areas alone.Instead,they involve connectivity among brain areas,whether close or distant.At that time,this approach was considered the optimal way to dissect brain circuitry and function.These pioneering efforts opened the field to explore the necessity or sufficiency of brain areas in controlling behavior and hence dissecting brain function.However,the connectivity of the brain and the mechanisms through which various brain regions regulate specific behaviors,either individually or collaboratively,remain largely elusive.Utilizing animal models,researchers have endeavored to unravel the necessity or sufficiency of specific brain areas in influencing behavior;however,no clear associations have been firmly established.
基金supported by the Guangdong Major Project of Basic and Applied Basic Research(Grant No.2020B0301030006).
文摘Magnesium matrix composites with both high strength and ductility have been achieved by introducing pure Ti particles.However,the properties of the surfaces of the composites need to be improved by surface technology,such as micro-arc oxidation(MAO).In this study,we investigated the influence of the Ti-reinforcement phase on coating growth and evolution by subjecting both AZ91 alloy and AZ91/Ti composite to MAO treatment using silicate-based and phosphate-based electrolytes.Results revealed that the Ti-reinforcement phase influenced the MAO process,altering discharge behavior,and leading to a decreased cell voltage.The vigorous discharge of the Ti-reinforcement phase induced the formation of coating discharge channels,concurrently dissolving and oxidizing Ti-reinforcement to produce a composite ceramic coating with TiO2.The MAO coating on the AZ91/Ti composite exhibited a dark blue macromorphology and distinctive local micromorphological anomalies.In silicate electrolyte,a“volcano-like”localized morphology centered on the discharge channel emerged.In contrast,treatment in phosphate-based electrolyte resulted in a coating morphology similar to typical porous ceramic coatings,with visible radial discharge micropores at the reinforcement phase location.Compared to the AZ91 alloy,the coating on the AZ91/Ti composite exhibited lower thickness and higher porosity.MAO treatment reduced the self-corrosion current density of the AZ91/Ti surface by two orders of magnitude.The silicate coating demonstrated better corrosion resistance than the phosphate coating,attributed to its lower porosity.The formation mechanism of MAO coatings on AZ91/Ti composites in phosphate-based and silicate-based electrolytes was proposed.
基金financially supported by National Natural Science Foundation of China(grant numbers:52171100,U20A20234)National Key R&D Program of China(grant number:2021YFB3701100)。
文摘The performance of Mg alloys is significantly influenced by the concentrations and solid solution behavior of the alloying elements.In this work,the solid solution behavior of 20 alloying elements in 190 ternary Mg alloy systems at 500℃are systematically investigated.The solid solution behavior of a set of two different alloying elements in Mg alloy systems are suggested to be classified into three categories:inclusivity,exclusivity and proportionality.Inclusivity classification indicates that the two alloying elements are inclusive inα-Mg,increasing the joint solubility of both elements.Exclusivity classification suggests that the two alloying elements have a low joint solid solubility inα-Mg,since they prefer to form stable second phases.For the proportionality classification,the solubility curve of the ternary Mg alloy systems is a straight line connecting the solubility points of the two sub-binary systems.The proposed classification theory was validated by key experiments and the calculation of formation energies.The interaction effects between alloying elements and the preference of formation of second phases are the main factors determining the solid solution behavior classifications.Based on the observed solid solution features of multi-component Mg alloys,principles for alloy design of different types of high-performance Mg alloys were proposed in this work.
基金support from the National Natural Science Foundation of China(grant number 52075544)Innovation Funds of Jihua Laboratory(X220971UZ230)+1 种基金Basic and Applied Basic Research Foundation of Guangdong Province(2022A1515110649)Funds from Research Platforms of Guangdong Higher Education Institutes(2022ZDJS038).
文摘Efficient lubrication of magnesium alloys is a highly challenging topic in the field of tribology.In this study,magnesium silicate hydroxide(MSH)nanotubes with serpentine structures were synthesized.The tribological behavior of AZ91D magnesium alloy rubbed against GCr15 steel was studied under lubricating oil with surface-modified MSH nanotubes as additives.The effects of the concentration,applied load,and reciprocating frequency on the friction and wear of the AZ91D alloy were studied using an SRV-4 sliding wear tester.Results show a decrease of 18.7–68.5%in friction coefficient,and a reduction of 19.4–54.3%in wear volume of magnesium alloy can be achieved by applying the synthetic serpentine additive under different conditions.A suspension containing 0.3 wt.%MSH was most efficient in reducing wear and friction.High frequency and medium load were more conducive to improving the tribological properties of magnesium alloys.A series of beneficial physical and chemical processes occurring at the AZ91D alloy/steel interface can be used to explain friction and wear reduction based on the characterization of the morphology,chemical composition,chemical state,microstructure,and nanomechanical properties of the worn surface.The synthetic MSH,with serpentine structure and nanotube morphology,possesses excellent adsorbability,high chemical activity,and good self-lubrication and catalytic activity.Therefore,physical polishing,tribochemical reactions,and physicalchemical depositions can occur easily on the sliding contacts.A dense tribolayer with a complex composition and composite structure was formed on the worn surface.Its high hardness,good toughness and plasticity,and prominent lubricity resulted in the improvement of friction and wear,making the synthetic MSH a promising efficient oil additive for magnesium alloys under boundary and mixed lubrication.
文摘This study aims to explore the characteristics of novice teachers’inappropriate behaviors in classroom teaching and their intervention strategies.With the continuous improvement of education quality,novice teachers face increasing challenges in teaching practice.Their inappropriate behaviors not only affect the classroom atmosphere but may also negatively impact students’learning outcomes.Therefore,researching the characteristics of novice teachers’inappropriate behaviors and their intervention strategies holds significant scientific and social value.This study employs a combination of quantitative and qualitative methods to analyze the behavioral patterns of novice teachers in classroom teaching and proposes corresponding intervention strategies.The results indicate that novice teachers’inappropriate behaviors mainly manifest as poor classroom management,monotonous teaching methods,and insufficient interaction with students.Based on these findings,the study proposes a series of effective intervention strategies,including enhancing teacher training,optimizing teaching design,and promoting positive interactions between teachers and students.The conclusions of the study not only provide practical guidance for educational practice but also point out directions for future research,emphasizing the crucial role of teacher professional development in improving teaching quality.
基金supported by the National Natural Science Foundation of China(Nos.52074228,52305420 and 51875470)the Practice and Innovation Funds for Graduate Students of Northwestern Polytechnical University,China(No.PF2024053)the Xi’an Beilin District Science and Technology Planning Project,China(No.GX2349).
文摘The pre-weld heat treatment was carried out to obtain different initial microstructures of the GH4169 superalloy,and then Linear Friction Welding(LFW)was performed.The effect of the pre-weld heat treatment on the microstructure evolution and mechanical properties of the joint was analyzed,and the joint electrochemical corrosion behavior as well as the hot corrosion behavior was studied.The results show that the joint hardness of Base Metal(BM)increases after pre-weld heat treatment,and the strengthening phasesγ′andγ″further precipitate.However,the precipitation phases dissolve significantly in the Weld Zone(WZ)due to the thermal process of LFW.The corrosion resistance in BM is reduced after the pre-weld heat treatment,while it is similar in WZ with a slight decrease.The surface morphology of the BM and WZ can be generally divided into a loose and porous matrix and a scattered oxide particle layer after hot corrosion.The joint cross section exhibits a Cr-depleted zone with the diffusion of Cr to form an oxide film.The corrosion product mainly consists of Fe_(2)O_(3)/Fe_(3)O_(4) as the outer layer and Cr_(2)O_(3) as the inner layer.
基金Project(42202318)supported by the National Natural Science Foundation of ChinaProject(252300421199)supported by the Natural Science Foundation of Henan Province,ChinaProject(2024JJ6219)supported by the Hunan Provincial Natural Science Foundation of China。
文摘The undrained mechanical behavior of unsaturated completely weathered granite(CWG)is highly susceptible to alterations in the hydraulic environment,particularly under uniaxial loading conditions,due to the unique nature of this soil type.In this study,a series of unconfined compression tests were carried out on unsaturated CWG soil in an underground engineering site,and the effects of varying the environmental variables on the main undrained mechanical properties were analyzed.Based on the experimental results,a novel constitutive model was then established using the damage mechanics theory and the undetermined coefficient method.The results demonstrate that the curves of remolded CWG specimens with different moisture contents and dry densities exhibited diverse characteristics,including brittleness,significant softening,and ductility.As a typical indicator,the unconfined compression strength of soil specimens initially increased with an increase in moisture content and then decreased.Meanwhile,an optimal moisture content of approximately 10.5%could be observed,while a critical moisture content value of 13.0%was identified,beyond which the strength of the specimen decreases sharply.Moreover,the deformation and fracture of CWG specimens were predominantly caused by shear failure,and the ultimate failure modes were primarily influenced by moisture content rather than dry density.Furthermore,by comparing several similar models and the experimental data,the proposed model could accurately replicate the undrained mechanical characteristics of unsaturated CWG soil,and quantitatively describe the key mechanical indexes.These findings offer a valuable reference point for understanding the underlying mechanisms,anticipating potential risks,and implementing effective control measures in similar underground engineering projects.
基金The authors would like to acknowledge the support of the National Natural Science Foundation of China(No.52279097,No.51779264)Blue and Green Project of Jiangsu Province.
文摘Natural cemented calcareous sand and limestone are highly complex and not well understood in terms of the me-chanical behavior due to the difficulty of obtaining undisturbed samples from far sea.This paper proposes an artificial method in a laboratory setting using microbial-induced carbonate precipitation(MICP)to simulate the natural process of cementation of limestone.The artificially cemented sand has a high degree of similarity with the natural weakly limestone in three aspects:(1)the mineral composition of the cemented material is also granular calcite and acicular aragonite;(2)the microstructure in interconnected open pore network can be gradually closed and contracted with cementation.The porosity reaches to approximately 9.2%;(3)both the stress-strain relationship and the unconfined strength closely resemble that of natural weakly limestone.Furthermore,both static and dynamic behaviors of artificial limestone were studied by quasi-static compression tests and Split Hopkinson Pressure Bar(SHPB)tests,finding that the unconfined strength of weakly artifical limestone exponentially increases with increasing strain rate.A rate-dependent bond strength was proposed and implemented in software to reveal the mechanism of strain rate effects.It is found that the loading velocity is too high to keep in sync with the initiation and propagation of cracks under impact loading.This delay-induced viscosity may restrict the movement of the surrounding balls,thus increasing resistance.
基金financial support from the National Natural Science Foundation of China(Nos.52233018 and 51831002)the China Baowu Low Carbon Metallurgy Innovation Foudation(No.BWLCF202213)。
文摘The influence of Nb-V microalloying on the hot deformation behavior and microstructures of medium Mn steel(MMS)was investigated by uniaxial hot compression tests.By establishing the constitutive equations for simulating the measured flow curves,we successfully constructed deformation activation energy(Q)maps and processing maps for identifying the region of flow instability.We concluded the following consequences of Nb-V alloying for MMS.(i)The critical strain increases and the increment diminishes with the increasing deformation temperature,suggesting that NbC precipitates more efficiently retard dynamic recrystallization(DRX)in MMS compared with solute Nb.(ii)The deformation activation energy of MMS is significantly increased and even higher than that of some reported high Mn steels,suggesting that its ability to retard DRX is greater than that of the high Mn content.(iii)The hot workability of MMS is improved by narrowing the hot processing window for the unstable flow stress,in which fine recrystallized and coarse unrecrystallized grains are present.
文摘Type 2 diabetes(T2D)is an insidious disease associated with neural and vascular complications,acceleration of cardiovascular disease,changes in heart function,and premature death.In the newly released article of the Journal of Sport and Health Science,Liang et al.1 describe results from the UK Biobank data showing the benefits of moderate-to-vigorous intensity physical activity(MVPA)on reducing the risks for vascular events in 11,474 adults with T2D and prediabetes.
基金funded in part by the German Research Foundation(Grant reference:496846758).
文摘The ongoing revolution in information technology is reshaping human life. In the realm of health behavior, wearable technology emerges as a leading digital solution,capturing physical behaviors (i.e., physical activity, sedentary habits, sleep patterns) within the 24-h cycle of daily life. Wearables are applied in research, clinical practice, and as lifestyle devices;most obvious, they promise to be a key element for increasing human physical activity, one of the biggest health challenges nowadays.
