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Unveiling the brain’s symphony:exploring the necessity and sufficiency of neural networks in behavior control
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作者 Fernando Jose Bustos 《Neural Regeneration Research》 SCIE CAS 2025年第1期186-187,共2页
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
关键词 behavior CONNECTIVITY neural
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Effect of Nb-V microalloying on the hot deformation behavior of medium Mn steels
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作者 Yumeng Wang Qinyi Guo +1 位作者 Bin Hu Haiwen Luo 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS 2025年第2期360-368,共9页
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
关键词 medium manganese steel niobium-vanadium microalloying flow behavior dynamic recrystallization hot workability
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Machine Learning Techniques in Predicting Hot Deformation Behavior of Metallic Materials
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作者 Petr Opela Josef Walek Jaromír Kopecek 《Computer Modeling in Engineering & Sciences》 SCIE EI 2025年第1期713-732,共20页
In engineering practice,it is often necessary to determine functional relationships between dependent and independent variables.These relationships can be highly nonlinear,and classical regression approaches cannot al... In engineering practice,it is often necessary to determine functional relationships between dependent and independent variables.These relationships can be highly nonlinear,and classical regression approaches cannot always provide sufficiently reliable solutions.Nevertheless,Machine Learning(ML)techniques,which offer advanced regression tools to address complicated engineering issues,have been developed and widely explored.This study investigates the selected ML techniques to evaluate their suitability for application in the hot deformation behavior of metallic materials.The ML-based regression methods of Artificial Neural Networks(ANNs),Support Vector Machine(SVM),Decision Tree Regression(DTR),and Gaussian Process Regression(GPR)are applied to mathematically describe hot flow stress curve datasets acquired experimentally for a medium-carbon steel.Although the GPR method has not been used for such a regression task before,the results showed that its performance is the most favorable and practically unrivaled;neither the ANN method nor the other studied ML techniques provide such precise results of the solved regression analysis. 展开更多
关键词 Machine learning Gaussian process regression artificial neural networks support vector machine hot deformation behavior
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Understanding the local structure and thermophysical behavior of Mg-La liquid alloys via machine learning potential
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作者 Jia Zhao Taixi Feng Guimin Lu 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS 2025年第2期439-449,共11页
The local structure and thermophysical behavior of Mg-La liquid alloys were in-depth understood using deep potential molecular dynamic(DPMD) simulation driven via machine learning to promote the development of Mg-La a... The local structure and thermophysical behavior of Mg-La liquid alloys were in-depth understood using deep potential molecular dynamic(DPMD) simulation driven via machine learning to promote the development of Mg-La alloys. The robustness of the trained deep potential(DP) model was thoroughly evaluated through several aspects, including root-mean-square errors(RMSEs), energy and force data, and structural information comparison results;the results indicate the carefully trained DP model is reliable. The component and temperature dependence of the local structure in the Mg-La liquid alloy was analyzed. The effect of Mg content in the system on the first coordination shell of the atomic pairs is the same as that of temperature. The pre-peak demonstrated in the structure factor indicates the presence of a medium-range ordered structure in the Mg-La liquid alloy, which is particularly pronounced in the 80at% Mg system and disappears at elevated temperatures. The density, self-diffusion coefficient, and shear viscosity for the Mg-La liquid alloy were predicted via DPMD simulation, the evolution patterns with Mg content and temperature were subsequently discussed, and a database was established accordingly. Finally, the mixing enthalpy and elemental activity of the Mg-La liquid alloy at 1200 K were reliably evaluated,which provides new guidance for related studies. 展开更多
关键词 magnesium-lanthanum liquid alloys local structure macroscopic properties thermodynamic behavior deep potential mo-lecular dynamic simulation
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Increased excitatory amino acid transporter 2 levels in basolateral amygdala astrocytes mediate chronic stress–induced anxiety-like behavior
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作者 Xirong Xu Shoumin Xuan +3 位作者 Shuai Chen Dan Liu Qian Xiao Jie Tu 《Neural Regeneration Research》 SCIE CAS 2025年第6期1721-1734,共14页
The conventional perception of astrocytes as mere supportive cells within the brain has recently been called into question by empirical evidence, which has revealed their active involvement in regulating brain functio... The conventional perception of astrocytes as mere supportive cells within the brain has recently been called into question by empirical evidence, which has revealed their active involvement in regulating brain function and encoding behaviors associated with emotions.Specifically, astrocytes in the basolateral amygdala have been found to play a role in the modulation of anxiety-like behaviors triggered by chronic stress. Nevertheless, the precise molecular mechanisms by which basolateral amygdala astrocytes regulate chronic stress–induced anxiety-like behaviors remain to be fully elucidated. In this study, we found that in a mouse model of anxiety triggered by unpredictable chronic mild stress, the expression of excitatory amino acid transporter 2 was upregulated in the basolateral amygdala. Interestingly, our findings indicate that the targeted knockdown of excitatory amino acid transporter 2 specifically within the basolateral amygdala astrocytes was able to rescue the anxiety-like behavior in mice subjected to stress. Furthermore, we found that the overexpression of excitatory amino acid transporter 2 in the basolateral amygdala, whether achieved through intracranial administration of excitatory amino acid transporter 2agonists or through injection of excitatory amino acid transporter 2-overexpressing viruses with GfaABC1D promoters, evoked anxiety-like behavior in mice. Our single-nucleus RNA sequencing analysis further confirmed that chronic stress induced an upregulation of excitatory amino acid transporter 2 specifically in astrocytes in the basolateral amygdala. Moreover, through in vivo calcium signal recordings, we found that the frequency of calcium activity in the basolateral amygdala of mice subjected to chronic stress was higher compared with normal mice.After knocking down the expression of excitatory amino acid transporter 2 in the basolateral amygdala, the frequency of calcium activity was not significantly increased, and anxiety-like behavior was obviously mitigated. Additionally, administration of an excitatory amino acid transporter 2 inhibitor in the basolateral amygdala yielded a notable reduction in anxiety level among mice subjected to stress. These results suggest that basolateral amygdala astrocytic excitatory amino acid transporter 2 plays a role in in the regulation of unpredictable chronic mild stress-induced anxiety-like behavior by impacting the activity of local glutamatergic neurons, and targeting excitatory amino acid transporter 2 in the basolateral amygdala holds therapeutic promise for addressing anxiety disorders. 展开更多
关键词 ANXIETY ASTROCYTES basolateral amygdala behavior dihydrokainic acid excitatory amino acid transporter 2 fiber photometry GLUTAMATE LDN-212320 TRANSPORTER
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Relationship between parenting stress and behavioral and emotional problems in preschool children: A mediation effect analysis
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作者 Zhi-Wei Fu Yue-Jing Li +3 位作者 Ran Yu Rui-Qing Guo Li-Xia Gao Sheng-Xia Zhao 《World Journal of Psychiatry》 SCIE 2025年第1期128-136,共9页
BACKGROUND Emotional reactions,such as anxiety,irritability,and aggressive behavior,have attracted clinical attention as behavioral and emotional problems in preschool-age children.AIM To investigate the current statu... BACKGROUND Emotional reactions,such as anxiety,irritability,and aggressive behavior,have attracted clinical attention as behavioral and emotional problems in preschool-age children.AIM To investigate the current status of family rearing,parental stress,and behavioral and emotional problems of preschool children and to analyze the mediating effect of the current status of family rearing on parental stress and behavioral/emo-tional problems.METHODS We use convenience sampling to select 258 preschool children in the physical examination center of our hospital from October 2021 to September 2023.The children and their parents were evaluated using a questionnaire survey.Pearson's correlation was used to analyze the correlation between child behavioral and emotional problems and parental stress and family rearing,and the structural equation model was constructed to test the mediating effect.RESULTS The score for behavioral/emotional problems of 258 preschool children was(27.54±3.63),the score for parental stress was(87.64±11.34),and the score for parental family rearing was(31.54±5.24).There was a positive correlation between the behavioral and emotional problems of the children and the“hostile/mandatory”parenting style;meanwhile,showed a negative correlation with the“support/participation”parenting style(all P<0.05).The intermediary effect value between the family upbringing of parents in parental stress and children's behavior problems was 29.89%.CONCLUSION Parental family upbringing has a mediating effect between parental stress and behavioral and emotional problems of children.Despite paying attention to the behavioral and emotional problems of preschool-age children,clinical medical staff should provide correct and reasonable parenting advice to their parents to promote the mental health of preschool-age children. 展开更多
关键词 Preschool children Parenting stress Children's behavioral and emotional problems Family rearing Mediating effect
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Macroscopic perspective on phase transition behavior of natural single-crystal graphite under different pressure environments
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作者 Xiaoshuang Yin Songyang Li +4 位作者 Lijuan Wang Peiyuan Liu Zhihai Cheng Huiyang Gou Liuxiang Yang 《Matter and Radiation at Extremes》 2025年第1期72-80,共9页
Comprehensive understanding of the direct transformation pathway from graphite to diamond under high temperature and high pressure has long been one of the fundamental goals in materials science.Despite considerable e... Comprehensive understanding of the direct transformation pathway from graphite to diamond under high temperature and high pressure has long been one of the fundamental goals in materials science.Despite considerable experimental and theoretical progress,current experimental studies have mainly focused on the local microstructural characterizations of recovered samples,which has certain limitations for hightemperature and high-pressure products,which often exhibit diversity.Here,we report on the pressure-induced phase transition behavior of natural single-crystal graphite under three distinct pressure-transmitting media from a macroscopic perspective using in situ two-dimensional Raman spectroscopy,scanning electron microscopy,and atomic force microscopy.The surface evolution process of graphite before and after the phase transition is captured,revealing that pressure-induced surface textures can impede the continuity of the phase transition process across the entire single crystal.Our results provide a fresh perspective for studying the phase transition behavior of graphite and greatly deepen our understanding of this behavior,which will be helpful in guiding further high-temperature and high-pressure syntheses of carbon allotropes. 展开更多
关键词 behavior TRANSITION phase
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What Is the Psychosocial Environment of Adolescents with High or Low Internalizing Behavior?
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作者 Changmin Yoo 《International Journal of Mental Health Promotion》 2025年第1期77-88,共12页
Objective:This study aimed to examine the developmental trajectories of internalizing behaviors among adolescents and to identify key personal and environmental factors associated with these developmental patterns ove... Objective:This study aimed to examine the developmental trajectories of internalizing behaviors among adolescents and to identify key personal and environmental factors associated with these developmental patterns over time.Methods:Data were collected from 2242 adolescents(49.6%girls,aged 13.9–18.9 years)in South Korea.Latent class growth analysis was used to identify distinct developmental patterns of internalizing behaviors.Multinomial logistic regression analyses were conducted to examine the associations between these developmental patterns and various factors including gender,self-esteem,abuse and neglect experiences,peer relationships,and media use.Results:The analysis revealed three latent classes of internalizing behavior trajectories among adolescents.The first group,the“mid decreasing group”,comprised 54.5%of the sample(1221 students),indicating a moderate level of internalizing behavior that declined over time.The second group,the“high decreasing group”,included 19.1%of the sample(429 students),characterized by initially high levels of internalizing behavior that decreased.The third group,the“low maintained group”,represented 26.4%of the sample(592 students),indicating consistently low levels of internalizing behavior.Factors such as gender,self-esteem,experiences of abuse and neglect,peer relationships(trust and alienation),smartphone dependency,and time spent watching TV/videos were significantly associated with these latent groups.Conclusion:Three distinct developmental patterns of internalizing behaviors were identified among adolescents:mid-decreasing(54.5%),high-decreasing(19.1%),and low-maintained(26.4%).Gender,self-esteem,abuse experiences,and peer relationships were significant predictors of these developmental patterns. 展开更多
关键词 Internalizing behavior adolescents longitudinal analysis
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Failure behaviors of anisotropic shale with a circular cavity subjected to uniaxial compression
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作者 Xianhui Feng Huilin Liu +4 位作者 Peitao Wang Shichao Zhang Quanqi Zhu Chun'an Tang Yaxing Leng 《Journal of Rock Mechanics and Geotechnical Engineering》 2025年第1期357-369,共13页
Layered rock formations are frequently encountered during the excavation of underground structures. The stability of such structures is influenced not only by the stress concentration caused by the cavities in the str... Layered rock formations are frequently encountered during the excavation of underground structures. The stability of such structures is influenced not only by the stress concentration caused by the cavities in the strata but also by the anisotropy of the layered rock mass. The interaction between them can lead to critical structural failure, such as rupture, collapse, or significant deformation within the adjacent rock mass, thereby jeopardizing operational safety. However, the coupling law and mechanism between the stress concentration resulting from the cavities and the anisotropy of a layered rock mass remain unclear. In this study, a uniaxial compression test was performed on shale specimens containing a circular hole to investigate the effects of layer inclination and circular holes on the mechanical properties, elastic energy storage, and failure behaviors of these specimens. The failure mechanism of the rock surrounding the hole was analyzed on the basis of the single plane of weakness theory and the Kirsch solution. The test results indicated pronounced anisotropy in the compressive strength, elastic modulus, and elastic strain energy of the specimens, with distinct “V”, “M” and “U”-shaped patterns correlated with varying layer inclination angles. In addition, the combined effect of stress concentration and layer inclination resulted in different failure types, which were classified into four groups according to their failure behavior. Theoretical analysis revealed that failure around circular holes in layered rock is affected by a range of variables, such as layer inclination, layer strength, lateral pressure coefficient, azimuth, and loading stress. 展开更多
关键词 ANISOTROPY SHALE Circular hole Mechanical properties Failure behaviors
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Activation of zona incerta gamma-aminobutyric acid-ergic neurons alleviates depression-like and anxiety-like behaviors induced by chronic restraint stress
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作者 Si-Hai Chen Bo Lan +8 位作者 Ying-Ying Zhang Guo-Hui Li Yu-Long Qian Ming-Xing Hu Yin-Lin Tian Wei-Dong Zang Jing Cao Guang-Hai Wang Yi-Gang Wang 《World Journal of Psychiatry》 2025年第2期209-221,共13页
BACKGROUND Depression is a prevalent affective disorder,but its pathophysiology remains unclear.Dysfunction in the gamma-aminobutyric acid(GABA)-ergic system may contribute to its onset.Recently,antidepressants(e.g.,b... BACKGROUND Depression is a prevalent affective disorder,but its pathophysiology remains unclear.Dysfunction in the gamma-aminobutyric acid(GABA)-ergic system may contribute to its onset.Recently,antidepressants(e.g.,brexanolone,zuranolone)targeting the GABA-A receptor were introduced.The zona incerta(ZI),an inhibitory subthalamic region mainly composed of GABAergic neurons,has been implicated in emotional regulation.Deep brain stimulation of the ZI in humans affects anxiety and depression symptoms,while activation of ZI neurons in mice can either worsen or alleviate anxiety.Currently,there is no direct evidence linking GABAergic neurons in the ZI to depression-like behaviors in rodents.AIM To explore the relationship between GABAergic neurons in the ZI and depression-like behaviors in mice.METHODS A chronic restraint stress(CRS)model was utilized to induce depression in mice.Whole-cell patch-clamp recordings assessed the excitability changes of GABAergic neurons in the ZI.Additionally,chemogenetic techniques were employed to modulate ZI GABAergic neurons.The performance of the mice in behavioral tests for depression and anxiety was observed.RESULTS The findings indicated that GABAergic neurons in the ZI were closely associated with depression-like behaviors in mice.Twenty-eight days after the CRS model was established,depression-like and anxiety-like behaviors were observed in the mice.The excitability of GABAergic neurons in the ZI was reduced.Chemogenetic activation of these neurons alleviated CRS-induced depression-like and anxiety-like behaviors.Conversely,inhibition of GABAergic neurons in the ZI led to changes in emotion-related behavioral outcomes in mice.CONCLUSION Activity of GABAergic neurons in the ZI was closely associated with depression-like phenotypes in mice,suggesting that these neurons could be a potential therapeutic target for treating depression. 展开更多
关键词 Zona incerta Gamma-aminobutyric acid-ergic DEPRESSION ANXIETY Animal behavior studies Whole-cell patchclamp
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Work-family behavioral role conflict and daytime sleepiness on suicide risk among Chinese nurses:A cross-sectional study
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作者 Qing-Wen Gan Yi-Ling Yuan +2 位作者 Yuan-Ping Li Yi-Wen Du Li-Lan Zheng 《World Journal of Psychiatry》 2025年第2期152-160,共9页
BACKGROUND Work-family conflicts and daytime sleepiness are related to the risk of suicide.At present,no study has investigated the relationship between nurses’work-family behavioral role conflict and suicide risk.Mo... BACKGROUND Work-family conflicts and daytime sleepiness are related to the risk of suicide.At present,no study has investigated the relationship between nurses’work-family behavioral role conflict and suicide risk.Moreover,it has not been confirmed whether,considering the effect of daytime sleepiness on suicide risk,daytime sleepiness mediates the effect of work-family behavioral role conflict and suicide risk.AIM To explore the pathway relationships among nurses'work-family behavioral role conflict,daytime sleepiness,and suicide risk.METHODS Convenience and purposive sampling methods were used to select 750 nurses from six provinces,including Jiangxi,Sichuan,and Shanxi.The work-family behavioral role conflict scale,the Chinese adult daytime sleepiness scale,and the suicide behavior questionnaire were used for the survey.The data were statistically analyzed via SPSS 25.0 software,Pearson correlation analysis was used to explore the correlations between the variables,the PROCESS 4.0 program was used for the mediation effect analysis,and the mediation effect model was tested via the bootstrap method.RESULTS Nurses'work-family behavioral role conflict and daytime sleepiness were positively correlated with suicide risk(r=734,0.717).Work-family behavioral role conflict positively predicted suicide risk(β=0.118),and daytime sleepiness positively predicted suicide risk(β=0.152).Daytime sleepiness partially mediated the role of nurses'work-family behavioral role conflict and suicide risk,with a mediation effect value of 0.046 and a mediation effect accounting for 38.98%.CONCLUSION The results of the Pearson correlation analysis and mediation effect analysis revealed that nurses'work-family behavioral role conflict has a direct effect on suicide risk and indirectly affects suicide risk through daytime drowsiness symptoms. 展开更多
关键词 Work-family behavioral role conflict Daytime sleepiness Suicide risk Mediating effect Nurses
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Thermal effects on the strain rate-dependent behavior of highly compacted GMZ01 bentonite
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作者 Pengju Qin Weimin Ye +1 位作者 Qiong Wang Yonggui Chen 《Journal of Rock Mechanics and Geotechnical Engineering》 2025年第1期453-464,共12页
Investigation of thermal effects on the strain rate-dependent properties of compacted bentonite is crucial for the long-term safety assessment of deep geological repository for disposal of high-level radioactive waste... Investigation of thermal effects on the strain rate-dependent properties of compacted bentonite is crucial for the long-term safety assessment of deep geological repository for disposal of high-level radioactive waste.In the present work,cylindrical GMZ01 bentonite specimens were compacted with suction-controlled by the vapor equilibrium technique.Then,a series of temperature-and suction-controlled stepwise constant rate of strain(CRS)tests was performed and the rate-dependent compressibility behavior of the highly compacted GMZ01 bentonite was investigated.The plastic compressibility parameterλ,the elastic compressibility parameterκ,the yield stress p0,as well as the viscous parameterαwere determined.Results indicate thatλ,κandαdecrease and p0 increases as suction increases.Upon heating,parametersλ,αand p0 decrease.It is also found that p0 increases linearly with increasing CRS in a double-logarithm coordinate.Based on the experimental results,a viscosity parameterα(s,T)was fitted to capture the effects of suction s and temperature T on the relationship between yield stress and strain rate.Then,an elastic-thermo-viscoplastic model for unsaturated soils was developed to describe the thermal effects on the rate-dependent behavior of highly compacted GMZ01 bentonite.Validation showed that the calculated results agreed well to the measured ones. 展开更多
关键词 Highly compacted bentonite Rate-dependent behavior Constant rate of strain Temperature Elastic-thermo-viscoplastic model
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Enhancing orthodontic osteodilated arch treatment through comprehensive nursing interventions and cognitive behavioral therapy
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作者 Haewon Byeon 《World Journal of Clinical Cases》 2025年第12期1-4,共4页
Orthodontic osteodilated arch treatment represents a pivotal approach in dental orthodontics to address dental crowding and misalignment.Integrating cognitive behavioral therapy(CBT)into comprehensive nursing interven... Orthodontic osteodilated arch treatment represents a pivotal approach in dental orthodontics to address dental crowding and misalignment.Integrating cognitive behavioral therapy(CBT)into comprehensive nursing interventions(CNI)aims to address these issues holistically.This editorial explores the effectiveness of CBTbased CNI in improving patient outcomes in orthodontic care.Innovations in remote CBT delivery,such as virtual reality,have also shown potential in reducing pain,anxiety,and depression,emphasizing CBT's adaptability in orthodontic settings.The findings underscore the importance of integrating psychological support into orthodontic care to enhance patient adherence,satisfaction,and overall treatment success.The editorial advocates for a holistic approach that combines psychological and physiological care,highlighting the transformative potential of CBT-based interventions in orthodontic treatment. 展开更多
关键词 Cognitive behavioral therapy Comprehensive nursing interventions Orthodontic care Patient compliance Psychological well-being
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An effective stress-based DSC model for predicting hydromechanical shear behavior of unsaturated collapsible soils subjected to initial shear stress
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作者 Saman Soleymani Borujerdi S.Mohsen Haeri +1 位作者 Amir Akbari Garakani Chandrakant SDesai 《Journal of Rock Mechanics and Geotechnical Engineering》 2025年第1期539-555,共17页
Evaluation of hydromechanical shear behavior of unsaturated soils is still a challenging issue. The time and cost needed for conducting precise experimental investigation on shear behavior of unsaturated soils have en... Evaluation of hydromechanical shear behavior of unsaturated soils is still a challenging issue. The time and cost needed for conducting precise experimental investigation on shear behavior of unsaturated soils have encouraged several investigators to develop analytical, empirical, or semi-empirical models for predicting the shear behavior of unsaturated soils. However, most of the previously proposed models are for specimens subjected to the isotropic state of stress, without considering the effect of initial shear stress. In this study, a hydromechanical constitutive model is proposed for unsaturated collapsible soils during shearing, with consideration of the effect of the initial shear stress. The model implements an effective stress-based disturbed state concept (DSC) to predict the stress-strain behavior of the soil. Accordingly, material/state variables were defined for both the start of the shearing stage and the critical state of the soil. A series of laboratory tests was performed using a fully automated unsaturated triaxial device to verify the proposed model. The experimental program included 23 suction-controlled unsaturated triaxial shear tests on reconstituted specimens of Gorgan clayey loess wetted to different levels of suctions under both isotropic and anisotropic stress states. The results show excellent agreement between the prediction by the proposed model and the experimental results. 展开更多
关键词 Unsaturated collapsible soil Initial shear stress Hydromechanical shear behavior Effective stress Disturbed state concept Critical state
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Plastic flow and interfacial bonding behaviors of embedded linear friction welding process:Numerical simulation combined with thermophysical experiment
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作者 Tiejun MA Zhenguo GUO +6 位作者 Xiawei YANG Junlong JIN Xi CHEN Jun TAO Wenya LI Achilles VAIRIS Liukuan YU 《Chinese Journal of Aeronautics》 2025年第1期87-98,共12页
In this study,a new linear friction welding(LFW)process,embedded LFW process,was put forward,which was mainly applied to combination manufacturing of long or overlong loadcarrying titanium alloy structural components ... In this study,a new linear friction welding(LFW)process,embedded LFW process,was put forward,which was mainly applied to combination manufacturing of long or overlong loadcarrying titanium alloy structural components in aircraft.The interfacial plastic flow behavior and bonding mechanism of this process were investigated by a developed coupling EulerianLagrangian numerical model using software ABAQUS and a novel thermo-physical simulation method with designed embedded hot compression specimen.In addition,the formation mechanism and control method of welding defects caused by uneven plastic flow were discussed.The results reveal that the plastic flow along oscillating direction of this process is even and sufficient.In the direction perpendicular to oscillation,thermo-plastic metals mainly flow downward along welding interface under coupling of shear stress and interfacial pressure,resulting in the interfacial plastic zone shown as an inverted“V”shape.The upward plastic flow in this direction is relatively weak,and only a small amount of flash is extruded from top of joint.Moreover,the wedge block and welding components at top of joint are always in un-steady friction stage,leading to nonuniform temperature field distribution and un-welded defects.According to the results of numerical simulation,high oscillating frequency combined with low pressure and small amplitude is considered as appropriate parameter selection scheme to improve the upward interfacial plastic flow at top of joint and suppress the un-welded defects.The results of thermo-physical simulation illustrate that continuous dynamic recrystallization(CDRX)induces the bonding of interface,accompanying by intense dislocation movement and creation of many low-angle grain boundaries.In the interfacial bonding area,grain orientation is random with relatively low texture density(5.0 mud)owing to CDRX. 展开更多
关键词 Embedded linear friction welding Plastic flow Interfacial bonding behavior Numerical simulation Thermo-physical simulation Temperature field Dynamic recrystallization
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Eco-environmental Quality Evaluation of Manasi River Basin in Recent 30 Years 被引量:6
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作者 张建龙 王月健 +1 位作者 丁武泉 谢付杰 《Meteorological and Environmental Research》 CAS 2010年第4期109-112,共4页
Taking the Technical Specifications of Eco-environmental Quality Assessment enacted by the State Environmental Protection Administration in 2006 as the conceptual framework model and improving some indices and weights... Taking the Technical Specifications of Eco-environmental Quality Assessment enacted by the State Environmental Protection Administration in 2006 as the conceptual framework model and improving some indices and weights in the regulation,the eco-environmental assessment index system for Manas River Basin was established,and the eco-environmental quality index (EQI) of this basin from 1976 to 2005 was assessed based on the related data.The results indicated that the ecological quality index increased to 48.26 from 34.44 during 1976-2005.The biologic abundance index,vegetation coverage index and land deterioration index decreased,while there was an increase in water reticulation density index,environmental quality index and pollution load index,so the improvement and deterioration of the ecological environment coexisted in the basin.On the whole,the poor state of the basin ecological environment had turned into a general state,and the eco-environmental quality was developed towards favorable circle.The results also showed that the improved calculating method of EQI accorded with the actual situation of the research area. 展开更多
关键词 Manasi River Basin eco-environmental quality evaluation eco-environmental quality index China
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The features of soil aggregation and its eco-environmental effects under different subalpine forests on the east slope of Gongga Mountain, China 被引量:3
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作者 张保华 何毓蓉 +1 位作者 周红艺 程根伟 《Journal of Forestry Research》 SCIE CAS CSCD 2003年第1期80-82,共3页
Structural properties of forest soils have important hydro-ecological function and can influence the soil water-physical characters and soil erosion. The experimental soil samples were obtained in surface horizon (0-1... Structural properties of forest soils have important hydro-ecological function and can influence the soil water-physical characters and soil erosion. The experimental soil samples were obtained in surface horizon (0-10 cm) from different subalpine forest types on east slope of Gongga Mountain in the upriver area of Yangtze River China in May 2002. The soil bulk density, porosity, stable infiltration rate, aggregate distribution and particle-size distribution were analyzed by the routine methods in room, and the features and effects on eco-environment of soil aggregation were studied. The results showed that the structure of soil under mixed mature forest is in the best condition and can clearly enhance the eco-environmental function of soil, and the soil structure under the clear-cutting forest is the worst, the others are ranked between them. The study results can offer a basic guidance for the eco-environmental construction in the upper reaches of Yangtze River. 展开更多
关键词 Soil aggregation eco-environmental effects Subalpine forest Gongga Mountain China
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The eco-environmental guarantee for China's urbanization process 被引量:15
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作者 方创琳 蔺雪芹 《Journal of Geographical Sciences》 SCIE CSCD 2009年第1期95-106,共12页
Studying the change of resources consumption and eco-environmental carrying capacity are of importance to the sustainable development of urbanization.Based on the China's economic and social statistical data from ... Studying the change of resources consumption and eco-environmental carrying capacity are of importance to the sustainable development of urbanization.Based on the China's economic and social statistical data from 1950 to 2006,the ecological footprint,eco-logical footprint intensity,ecological deficit and surplus,and eco-environment quality com-prehensive index are calculated,the correlation between urbanization and eco-environmental change is analyzed and the eco-environmental guarantee for China's urbanization in 2030 is forecasted.The major results could be summarized as follows:(1) there is a positive linear relation between urbanization and ecological footprint,negative linear relation between ur-banization and ecological footprint intensity,ecological deficit and surplus and the negative exponential relation between urbanization and eco-environment quality comprehensive index.(2) By 2030,the urbanization level will reach 61.32%,the ecological deficit will increase to 42.2866×108 hm2 and the eco-environment quality comprehensive index will drop to 0.3016 on the condition that the total quantity ecological footprint achieves 55.9348×108 hm2.(3) Under the existing urban development pattern,the ecological overload will be more serious in the next 24 years.Constructing the reasonable industrial structure and establishing the intensive resources utilization system to alleviate the eco-environmental pressure are the tough challenges in China's urbanization process. 展开更多
关键词 URBANIZATION eco-environmental guarantee coupling relationship ecological footprint China
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CATASTROPHIC ECO-ENVIRONMENTAL CHANGE IN THE SONGNEN PLAIN,NORTHEASTERN CHINA SINCE 1900S 被引量:6
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作者 WANGHai-xia WANZhong-juan +2 位作者 YUShao-peng LUOXin-zheng SUNGuang-you 《Chinese Geographical Science》 SCIE CSCD 2004年第2期179-185,共7页
Although the Songnen Plain in the northeastern China was developed relatively late in the temperate zone of the world, its eco-environment has changed greatly. This paper analyzes the changes of land cover and the rat... Although the Songnen Plain in the northeastern China was developed relatively late in the temperate zone of the world, its eco-environment has changed greatly. This paper analyzes the changes of land cover and the rates and trends ofdesertification during the past 100 years in the Songnen Plain. According to the macroscopic analysis, we find that the eco-environment in the plain has reached to the threshold of catastrophic change since the 1950s. The Thom Needle Catastrophic Model was used to determine and validate this conclusion. Human activities, including large-scale construction projects, such as huge dams and dikes, and excessive grazing were the primary factors contributing to regional eco-environmental catastrophe. And irrational reclamation of the wilderness also affected the eco-environmental change. The results reveal the complex human-land interactions. 展开更多
关键词 eco-environment CATASTROPHE modeling Songnen Plain
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Quantitative Evaluation of Sustainable Development and Eco-Environmental Carrying Capacity in Water-Deficient Regions:A Case Study in the Haihe River Basin,China 被引量:22
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作者 WANG Zhong-gen LUO Yu-zhou +1 位作者 ZHANG Ming-hua XIA Jun 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2014年第1期195-206,共12页
Quantitative assessment of development sustainability could be a challenge to regional management and planning, especially for areas facing great risks of water shortage. Surface-water decline and groundwater over-pum... Quantitative assessment of development sustainability could be a challenge to regional management and planning, especially for areas facing great risks of water shortage. Surface-water decline and groundwater over-pumping have caused serious environmental problems and limited economic development in many regions all around the world. In this paper, a framework for quantitatively evaluating development sustainability was established with water-related eco-environmental carrying capacity (EECC) as the core measure. As a case study, the developed approach was applied to data of the Haihe River Basin, China, during 1998 through 2007. The overall sustainable development degree (SDD) is determined to be 0.39, suggesting that this rate of development is not sustainable. Results of scenario analysis revealed that overshoot, or resource over- exploitation, of the Basin's EECC is about 20% for both population and economy. Based on conditions in the study area in 2007, in order to achieve sustainable development, i.e., SDD〉0.70 in this study, the EECC could support a population of 108 million and gross domestic product (GDP) of 2.72 trillion CNY. The newly developed approach in quantifying ecoenvironmental carrying capacity is anticipated to facilitate sustainable development oriented resource management in waterdeficient areas. 展开更多
关键词 eco-environmental carrying capacity development scenario Haihe River Basin sustainable development waterresources
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