Background Globally,populations afflicted by armed conflict are known to have high rates of mental health disorders.Aims This meta-analysis aims to estimate the prevalence of post-traumatic stress disorder(PTSD)and de...Background Globally,populations afflicted by armed conflict are known to have high rates of mental health disorders.Aims This meta-analysis aims to estimate the prevalence of post-traumatic stress disorder(PTSD)and depressive symptoms among civilians residing in armed conflictaffected regions.Methods This meta-analysis was conducted in accordance with the Preferred Reporting Items forSystematic Reviews and Meta-Analyses.A literature search employing MEDLINE(R),Embase Classic+Embase,APA PsyclNFO,Ovid Healthstar,Journal@Ovid Full Text,Cochrane,PTSDpubs and CINAHL was conducted from inception until 19 March 2024 to identify relevant studies.Quality assessment was performed using the Joanna Briggs Institute Critical Appraisal Checklist for Prevalence Studies,and a Comprehensive Meta-Analysiswas usedto conduct the statistical analysis.Results The search yielded 38595 articles,of which 57 were considered eligible for inclusion.The included studies comprised data from 64596 participants.We estimated a prevalence of 23.70%(95%CI 19.50%to28.40%)forPTSD symptomsand 25.60%(95%Cl 20.70%to 31.10%)for depressive features among war-afflicted civilians.The subgroup analysis based on time since the war and the country's economic status revealed the highest prevalence for both PTSD and depressive symptoms was present during the years of war and in low/middle-incomecountries.Conclusions The results of this study provide conclusive evidence of the detrimental impacts of armed conflict on mental health outcomes.Hence,it is crucial to emphasise the significance of both physical and mental health in the aftermath of war and take appropriate humanistic measures to overcome challenges in the management of psychiatric illnesses.展开更多
In the design realm of fusion power supplies,structural components play a pivotal role in ensuring the safety of fusion devices.To verify the reliability of the converter structure design at the Comprehensive Research...In the design realm of fusion power supplies,structural components play a pivotal role in ensuring the safety of fusion devices.To verify the reliability of the converter structure design at the Comprehensive Research Facility for Fusion Technology(CRAFT),meticulous analysis of the converter's dynamic impact is carefully performed based on the worst fault current(400k A),firstly.Subsequently,the thermal stress analysis based on the maximum allowable steadystate temperature is finished,and the equivalent thermal stress,thermal deformation,maximum shear stress of a single bridge arm and the whole converter are studied.Furthermore,a simple research method involving the current-sharing characteristics of a bridge arm with multithyristor parallel connection is proposed using a combination of Simplorer with Q3D in ANSYS.The results show that the current-sharing characteristics are excellent.Finally,the structural design has been meticulously tailored to meet the established requirements.展开更多
Foam concrete is a prospective material in defense engineering to protect structures due to its high energy absorption capability resulted from the long plateau stage.However,stress enhancement rather than stress miti...Foam concrete is a prospective material in defense engineering to protect structures due to its high energy absorption capability resulted from the long plateau stage.However,stress enhancement rather than stress mitigation may happen when foam concrete is used as sacrificial claddings placed in the path of an incoming blast load.To investigate this interesting phenomenon,a one-dimensional difference model for blast wave propagation in foam concrete is firstly proposed and numerically solved by improving the second-order Godunov method.The difference model and numerical algorithm are validated against experimental results including both the stress mitigation and the stress enhancement.The difference model is then used to numerically analyze the blast wave propagation and deformation of material in which the effects of blast loads,stress-strain relation and length of foam concrete are considered.In particular,the concept of minimum thickness of foam concrete to avoid stress enhancement is proposed.Finally,non-dimensional analysis on the minimum thickness is conducted and an empirical formula is proposed by curve-fitting the numerical data,which can provide a reference for the application of foam concrete in defense engineering.展开更多
Genes in the glycogen synthase kinase 3(GSK3)family are essential in regulating plant response to stressful conditions.This study employed bioinformatics to uncover the GSK3 gene family from the sunflower genome datab...Genes in the glycogen synthase kinase 3(GSK3)family are essential in regulating plant response to stressful conditions.This study employed bioinformatics to uncover the GSK3 gene family from the sunflower genome database.The expressions of GSK3 genes in different tissues and stress treatments,such as salt,drought,and cold,were assessed using transcriptome sequencing and quantitative real-time PCR(qRT-PCR).The study results revealed that the 12 GSK3 genes of sunflower,belonging to four classes(Classes I–IV),contained the GSK3 kinase domain and 11–13 exons.The majority of GSK3 genes were highly expressed in the leaf axil and flower,while their expression levels were relatively lower in the leaf.As a result of salt stress,six of the GSK3 genes(HaSK11,HaSK22,HaSK23,HaSK32,HaSK33,and HaSK41)displayed a notable increase in expression,while HaSK14 and HaSK21 experienced a significant decrease.With regard to drought stress,five of the GSK3 genes(HaSK11,HaSK13,HaSK21,HaSK22,and HaSK33)experienced a remarkable rise in expression.When exposed to cold stress,seven of the GSK3 genes(HaSK11,HaSK12,HaSK13,HaSK32,HaSK33,HaSK41,and HaSK42)showed a substantial increase,whereas HaSK21 and HaSK23 had a sharp decline.This research is of great importance in understanding the abiotic resistance mechanism of sunflowers and developing new varieties with improved stress resistance.展开更多
This paper reviews works on the dynamic analysis of flexible and rigid pavements under moving vehicles on the basis of continuum-based plane strain models and linear theories.The purpose of this review is to provide i...This paper reviews works on the dynamic analysis of flexible and rigid pavements under moving vehicles on the basis of continuum-based plane strain models and linear theories.The purpose of this review is to provide in-formation about the existing works on the subject,critically discuss them and make suggestions for further research.The reviewed papers are presented on the basis of the various models for pavement-vehicle systems and the various methods for dynamically analyzing these systems.Flexible pavements are modeled by a homogeneous or layered half-plane with isotropic or anisotropic and linear elastic,viscoelastic or poroelastic material behavior.Rigid pavements are modeled by a beam or plate on a homogeneous or layered half-plane with material properties like the ones for flexible pavements.The vehicles are modeled as concentrated or distributed over a finite area loads moving with constant or time dependent speed.The above pavement-vehicle models are dynamically analyzed by analytical,analytical/numerical or purely numerical methods working in the time or frequency domain.Representative examples are presented to illustrate the models and methods of analysis,demonstrate their merits and assess the effects of the various parameters on pavement response.The paper closes with con-clusions and suggestions for further research in the area.The significance of this research effort has to do with the presentation of the existing literature on the subject in a critical and easy to understand way with the aid of representative examples and the identification of new research areas.展开更多
A more accurate estimation of stress-strain relationships for martensite and ferrite was developed, and the modified law of mixture was used to investigate the stress-strain partitioning of constituent phases in dual ...A more accurate estimation of stress-strain relationships for martensite and ferrite was developed, and the modified law of mixture was used to investigate the stress-strain partitioning of constituent phases in dual phase (DP) steels with two different martensite volume fractions. The results show that there exist great differences in the stress-strain contribution of martensite and ferrite to DP steel. The stress-strain partitioning coefficient is not constant in the whole strain range, but decreases with increasing the true strain of DP steel. The softening effect caused by the dilution of carbon concentration in martensite with the increase of martensite volume fraction has great influence on the strain contribution of martensite. The strain ratio of ferrite to martensite almost linearly increases with increasing the true strain of DP steel when the martensite volume fraction is 22%, because martensite always keeps elastic. But the strain ratio of ferrite to martensite varies indistinctively with the further increase in true strain of DP steel above 0.034 when the martensite volume fraction is 50%, because plastic deformation happens in martensite. The stress ratio ofmartensite to ferrite decreases monotonously with increasing the true strain of DP steel whether the martensite volume fraction is 22% or 50%.展开更多
Objective:To understand the latent categories of perceived stress in colorectal cancer patients and analyze the characteristics of different categories of patients.Methods:A total of 255 colorectal cancer patients rec...Objective:To understand the latent categories of perceived stress in colorectal cancer patients and analyze the characteristics of different categories of patients.Methods:A total of 255 colorectal cancer patients receiving treatment in the gastrointestinal surgery and oncology depar tments of a ter tiary Grade A hospital in Sichuan Province,from January 2023 to June 2023,were selected as the study subjects.General information questionnaire,Chinese version of the Perceived Stress Scale(CPSS),and Comprehensive Score Table for Patient-Repor ted Outcome Measures of Economic Toxicity(COST-PROM)were used for data collection.Results:Perceived stress in colorectal cancer patients was classified into 3 latent categories:C1“Low stress-stable type”(19.2%),C2“Moderate stress-uncontrolled type”(23.9%),and C3“High stress-anxious type”(56.9%).The average score of perceived stress was(34.07±5.08).Compared with C1 type,patients with a monthly household income of≤3000 RMB were more likely to belong to the C2 and C3 types(P<0.05),and patients without a stoma were less likely to belong to C3 type(P<0.05).Compared with C2 type,male patients were more likely to belong to C3 type(P<0.05),and patients without a stoma were less likely to belong to C3 type(P<0.05).Compared with C3 type,patients with higher economic toxicity scores were more likely to be classified into C1 and C2 types(P<0.05).Conclusions:Perceived stress in colorectal cancer patients exhibits distinct categorical features.Male gender,lower income,presence of a stoma,and higher economic toxicity are associated with higher levels of perceived stress in colorectal cancer patients.展开更多
The magnitude of tensile stress and tensile strain at an anastomosis site under physiological stress is an important factor for the success of anastomosis following suturing in peripheral nerve injury treatment. Sciat...The magnitude of tensile stress and tensile strain at an anastomosis site under physiological stress is an important factor for the success of anastomosis following suturing in peripheral nerve injury treatment. Sciatic nerves from fresh adult cadavers were used to create models of sciatic nerve injury. The denervated specimens underwent epineurial and perineurial suturing. The elastic modulus (40.96 + 2.59 MPa) and Poisson ratio (0.37 + 0.02) of the normal sciatic nerve were measured by strain electrical measurement. A resistance strain gauge was pasted on the front, back left, and right of the edge of the anastomosis site after suturing. Strain electrical measurement results showed that the stress and strain values of the sciatic nerve following perineurial suturing were lower than those following epineurial suturing. Scanning electron microscopy revealed that the sciatic nerve fibers were disordered following epineurial compared with perineurial suturing. These results indicate that the effect of perineurial suturing in sciatic nerve injury repair is better than that of epineurial suturing.展开更多
The microstructure of surface peeling in finish rolled Cu-0.1Fe-0.03P sheetis analyzed by scanning electron microscope and energy dispersive spectroscope. Fe-rich areas ofdifferent contents are observed in the matrix....The microstructure of surface peeling in finish rolled Cu-0.1Fe-0.03P sheetis analyzed by scanning electron microscope and energy dispersive spectroscope. Fe-rich areas ofdifferent contents are observed in the matrix. The stress distributions and strain characteristicsat the interface between Cu matrix and Fe particle are studied by elastic-plastic finite elementplane strain model. Larger Fe particles and higher deforming extent of finish rolling are attributedto the intense stress gradient and significant non-homogeneity equivalent strain at the interfaceand accelerate surface peeling of Cu-0.1Fe-0.03P lead frame sheet.展开更多
The effect of strain hardening and strain softening behavior of flow stress changing with temperature on welding residual stress, plastic strain and welding distortion of ATN0 1-T4 aluminum alloy was studied by finite...The effect of strain hardening and strain softening behavior of flow stress changing with temperature on welding residual stress, plastic strain and welding distortion of ATN0 1-T4 aluminum alloy was studied by finite simulation method. The simulation results show that the weld seam undergoes strain hardening in the temperature range of 180-250 ℃, however, it exhibits strain softening at temperature above 250 ℃ during welding heating and cooling process. As a result, the strain hardening and strain softening effects counteract each other, introducing slightly influence on the welding residual stress, residual plastic strain and distortion. The welding longitudinal residual stress was determined by ultrasonic stress measurement method for the flat plates of A7N01-T4 aluminum alloy. The simulation results are well accordant with test ones.展开更多
We studied the effect of loose tenon dimensions on stress and strain distributions in T-shaped mortise and loose tenon (M&amp;LT) furni-ture joints under uniaxial bending loads, and determined the effects of loose ...We studied the effect of loose tenon dimensions on stress and strain distributions in T-shaped mortise and loose tenon (M&amp;LT) furni-ture joints under uniaxial bending loads, and determined the effects of loose tenon length (30, 45, 60, and 90 mm) and loose tenon thickness (6 and 8 mm) on bending moment capacity of M&amp;LT joints constructed with polyvinyl acetate (PVAc) adhesive. Stress and strain distributions in joint elements were then estimated for each joint using ANSYS finite element (FE) software. The bending moment capacity of joints increased significantly with thickness and length of the tenon. Based on the FE analysis results, under uniaxial bending, the highest shear stress values were obtained in the middle parts of the tenon, while the highest shear elastic strain values were estimated in glue lines between the tenon sur-faces and walls of the mortise. Shear stress and shear elastic strain values in joint elements generally increased with tenon dimensions and corre-sponding bending moment capacities. There was consistency between predicted maximum shear stress values and failure modes of the joints.展开更多
In this paper, we perform systematic calculations of the stress and strain distributions in InAs/GaAs truncated pyramidal quantum dots (QDs) with different wetting layer (WL) thickness, using the finite element me...In this paper, we perform systematic calculations of the stress and strain distributions in InAs/GaAs truncated pyramidal quantum dots (QDs) with different wetting layer (WL) thickness, using the finite element method (FEM). The stresses and strains are concentrated at the boundaries of the WL and QDs, are reduced gradually from the boundaries to the interior, and tend to a uniform state for the positions away from the boundaries. The maximal strain energy density occurs at the vicinity of the interface between the WL and the substrate. The stresses, strains and released strain energy are reduced gradually with increasing WL thickness. The above results show that a critical WL thickness may exist, and the stress and strain distributions can make the growth of QDs a growth of strained three-dimensional island when the WL thickness is above the critical value, and FEM can be applied to investigate such nanosystems, QDs, and the relevant results are supported by the experiments.展开更多
Light beam deflections caused by stress or strain gradients are inves- tigated analytically and experimentally in homogeneous beam specimens which are subjected to a particular case of flexure with shear. This study i...Light beam deflections caused by stress or strain gradients are inves- tigated analytically and experimentally in homogeneous beam specimens which are subjected to a particular case of flexure with shear. This study is a generalization of the prior an alytical-experimental examination of strain-gradient light deflections produced in stressed plates, which had concentrated on the simplest case where in- formation of interest is collected along a line of symmetry of the stress field. Main purpose of the present investigation is to document the efficacy of the strain-gradient method in analysis of the general case of stress state. The most interesting stress state is that in a beam subjected to the Saint-Venant bending, where the transversal and the longitudinal axes of the beam are in pure shear. The obtained results are compared with the predictions of the developed analytical models and with the pre- dictions of Filon's stress function. The procedures of evaluating the photoelastic and material coefficients using strain-gradient techniques were tested positively.展开更多
The plane structure of bars jointed to a rigid-body is a complex and universal structure.Some other structure of bars can be considered as its special cases. Many material have different stress-strain relation in tens...The plane structure of bars jointed to a rigid-body is a complex and universal structure.Some other structure of bars can be considered as its special cases. Many material have different stress-strain relation in tension and compression, generally the relation is nonlinear. In this paper,we use the constitutive model of linearly elastic and power hardening of strength difference to analyze plane structure of bars. The displacement method is used to derive the universal expression of calculating stress and strain. The nonlinear equations for computing displacements of the rigid-body has been given and general computing program has been worked out. This problem has been solved satisfactorily.展开更多
In this paper, the stress-strain curve of material is fitted by polygonal line composed of three lines. According to the theory of proportional loading in elastoplasticity, we simplify the complete stress-strain relat...In this paper, the stress-strain curve of material is fitted by polygonal line composed of three lines. According to the theory of proportional loading in elastoplasticity, we simplify the complete stress-strain relations, which are given by the increment theory of elastoplasticity. Thus, the finite element equation with the solution of displacement is derived. The assemblage elastoplastic stiffness matrix can be obtained by adding something to the elastic matrix, hence it will shorten the computing time. The determination of every loading increment follows the von Mises yield criteria. The iterative method is used in computation. It omits the redecomposition of the assemblage stiffness matrix and it will step further to shorten the computing time. Illustrations are given to the high-order element application departure from proportional loading, the computation of unloading fitting to the curve and the problem of load estimation.展开更多
Estimation of in situ stresses based on back-analysis of measured stress changes and displacements has become an alternative to the direct stress measurement methods.In order to help users conduct own measurement and ...Estimation of in situ stresses based on back-analysis of measured stress changes and displacements has become an alternative to the direct stress measurement methods.In order to help users conduct own measurement and analysis,this paper presents in detail a field stress back-analysis approach directly from borehole strain changes measured during nearby underground excavation.Essential formulations in major steps and the procedure for the entire analysis process are provided to allow users to follow.The instrument for borehole strain change measurement can be the CSIR or CSIRO stress cells and other borehole strain cells that can measure strains on borehole walls.Strain changes corresponding to the stress changes at a borehole location are calculated in borehole environment.The stress changes due to nearby excavation can be calculated by an analytical model for a single circular opening and simulated by a numerical model for non-circular and multiple openings.These models are based on isotropic,homogeneous and linear elastic assumptions.The analysis of borehole strain changes is accomplished by multiple linear regression based on error minimization and an integrated process provides the best-fit solution directly to the in situ stresses.A statistical technique is adopted for screening outliers in the measurement data,checking measurement compatibility and evaluating the reliability of analysis results.An application example is included to demonstrate the practical application and the analysis procedure.展开更多
The design temperature of high plutonium concentration ZPPR fuel plates is 600°C. Cladding integrity of the 304 L stainless steel cladding is a significant concern with this fuel since even small holes can lead t...The design temperature of high plutonium concentration ZPPR fuel plates is 600°C. Cladding integrity of the 304 L stainless steel cladding is a significant concern with this fuel since even small holes can lead to substantial fuel degradation. Since the fuel has a higher coefficient of thermal expansion than the cladding, an investigation of the stress induced in the cladding due to the differential thermal expansion of fuel and cladding up to the design temperature was conducted. Small holes in the cladding envelope would be expected to lead to the fuel hydriding and oxidizing into a powder over a long period of time. This is the same type of chemical reaction chain that exists in the degradation of the high uranium concentration ZPPR fuel. Unfortunately, the uranium fuel was designed with vents which allowed this degradation to occur. The Pu cladding is sealed so only fuel with damaged cladding would be subject to this damage. The thermal stresses that can be developed in the fuel cladding have been calculated in this paper and compared to the ultimate tensile stress of the cladding. The conclusion is drawn that thermal stresses cannot induce holes in the cladding even for the highest storage temperatures predicted in calculations (292°C). In fact, thermal stress cannot cause cladding failure as long as the fuel temperatures are below the design limit of 600°C (1112°F).展开更多
A new method was denonstrated to determine stress in a single crystal for multicrystal material and this new method could be specially applied for any symmetric crystalline systems. The strain tensor e was determined ...A new method was denonstrated to determine stress in a single crystal for multicrystal material and this new method could be specially applied for any symmetric crystalline systems. The strain tensor e was determined by the change of the metric tensor G before the initial state and after the deformed state in the crystal reference system. Then stress tensor at grain scale was calculated by the HOOK's law. The stress evaluations were carried out in coarse grains of a thin galvanized coating on a steel substrate during tensile loading. This makes it possible to link the microstructure evolution to the elastic heterogeneity at grain scale or between the grains.展开更多
This research presents an experimental study of analysis of stress strain state SSS of X-60 pipe weld joints employing magnetic anisotropy indicator of mechanical stresses Stress Vision (IMS) using of “before and af...This research presents an experimental study of analysis of stress strain state SSS of X-60 pipe weld joints employing magnetic anisotropy indicator of mechanical stresses Stress Vision (IMS) using of “before and after” comparison approach taking readings on pipe base metal, weld area and heat affected zone (HAZ) before and after hydrotest. Test results were compared with X-ray testing results for welded joints and with metallographic testing. Test results demonstrate the relevance of applied test conditions and redistribution of residual stresses. A new equation was established for estimating the residual (technological) and operating stresses in other pipelines with a tolerance of 15% in the field of elastic deformation (up to the yield point), according to Hooke law.展开更多
Engineering members often include cutouts.Although the structural integrity of such members can be highly influenced by associated stresses,determining them may be very challenging for finite shapes operating in an in...Engineering members often include cutouts.Although the structural integrity of such members can be highly influenced by associated stresses,determining them may be very challenging for finite shapes operating in an industrial environment.This is particularly so if the loading is not well known,a common occurrence in practical situations.While photomechanical methods can be effective,they necessitate optical access to the component,something which is also often unavailable.Recognizing the above,this paper demonstrates ability to determine the complete stresses throughout a perforated tensile plate using only aligned,single-element strain gages rather than multi-element rosettes.Although reliability is verified using finite elements,an objective of the technique is for situations when finite element methods are not feasible,e.g.,the loading is inadequately known.The approach is applicable to members fabricated from isotropic,orthotropic or functionally-graded materials and is not restricted to a particular shape,cutout arrangement or loading condition.展开更多
文摘Background Globally,populations afflicted by armed conflict are known to have high rates of mental health disorders.Aims This meta-analysis aims to estimate the prevalence of post-traumatic stress disorder(PTSD)and depressive symptoms among civilians residing in armed conflictaffected regions.Methods This meta-analysis was conducted in accordance with the Preferred Reporting Items forSystematic Reviews and Meta-Analyses.A literature search employing MEDLINE(R),Embase Classic+Embase,APA PsyclNFO,Ovid Healthstar,Journal@Ovid Full Text,Cochrane,PTSDpubs and CINAHL was conducted from inception until 19 March 2024 to identify relevant studies.Quality assessment was performed using the Joanna Briggs Institute Critical Appraisal Checklist for Prevalence Studies,and a Comprehensive Meta-Analysiswas usedto conduct the statistical analysis.Results The search yielded 38595 articles,of which 57 were considered eligible for inclusion.The included studies comprised data from 64596 participants.We estimated a prevalence of 23.70%(95%CI 19.50%to28.40%)forPTSD symptomsand 25.60%(95%Cl 20.70%to 31.10%)for depressive features among war-afflicted civilians.The subgroup analysis based on time since the war and the country's economic status revealed the highest prevalence for both PTSD and depressive symptoms was present during the years of war and in low/middle-incomecountries.Conclusions The results of this study provide conclusive evidence of the detrimental impacts of armed conflict on mental health outcomes.Hence,it is crucial to emphasise the significance of both physical and mental health in the aftermath of war and take appropriate humanistic measures to overcome challenges in the management of psychiatric illnesses.
基金supported by the Talent Research Fund of Hefei University(No.21-22RC09)National Natural Science Foundation of China(No.U22A20225)。
文摘In the design realm of fusion power supplies,structural components play a pivotal role in ensuring the safety of fusion devices.To verify the reliability of the converter structure design at the Comprehensive Research Facility for Fusion Technology(CRAFT),meticulous analysis of the converter's dynamic impact is carefully performed based on the worst fault current(400k A),firstly.Subsequently,the thermal stress analysis based on the maximum allowable steadystate temperature is finished,and the equivalent thermal stress,thermal deformation,maximum shear stress of a single bridge arm and the whole converter are studied.Furthermore,a simple research method involving the current-sharing characteristics of a bridge arm with multithyristor parallel connection is proposed using a combination of Simplorer with Q3D in ANSYS.The results show that the current-sharing characteristics are excellent.Finally,the structural design has been meticulously tailored to meet the established requirements.
基金supported by the National Natural Science Foundation of China (Grant No.52178515)。
文摘Foam concrete is a prospective material in defense engineering to protect structures due to its high energy absorption capability resulted from the long plateau stage.However,stress enhancement rather than stress mitigation may happen when foam concrete is used as sacrificial claddings placed in the path of an incoming blast load.To investigate this interesting phenomenon,a one-dimensional difference model for blast wave propagation in foam concrete is firstly proposed and numerically solved by improving the second-order Godunov method.The difference model and numerical algorithm are validated against experimental results including both the stress mitigation and the stress enhancement.The difference model is then used to numerically analyze the blast wave propagation and deformation of material in which the effects of blast loads,stress-strain relation and length of foam concrete are considered.In particular,the concept of minimum thickness of foam concrete to avoid stress enhancement is proposed.Finally,non-dimensional analysis on the minimum thickness is conducted and an empirical formula is proposed by curve-fitting the numerical data,which can provide a reference for the application of foam concrete in defense engineering.
基金financed by the Anhui Provincial Central Leading Local Science and Technology Development Special Fund Project(202007d06020021)Project of Suzhou Science and Technology Bureau(2021143).
文摘Genes in the glycogen synthase kinase 3(GSK3)family are essential in regulating plant response to stressful conditions.This study employed bioinformatics to uncover the GSK3 gene family from the sunflower genome database.The expressions of GSK3 genes in different tissues and stress treatments,such as salt,drought,and cold,were assessed using transcriptome sequencing and quantitative real-time PCR(qRT-PCR).The study results revealed that the 12 GSK3 genes of sunflower,belonging to four classes(Classes I–IV),contained the GSK3 kinase domain and 11–13 exons.The majority of GSK3 genes were highly expressed in the leaf axil and flower,while their expression levels were relatively lower in the leaf.As a result of salt stress,six of the GSK3 genes(HaSK11,HaSK22,HaSK23,HaSK32,HaSK33,and HaSK41)displayed a notable increase in expression,while HaSK14 and HaSK21 experienced a significant decrease.With regard to drought stress,five of the GSK3 genes(HaSK11,HaSK13,HaSK21,HaSK22,and HaSK33)experienced a remarkable rise in expression.When exposed to cold stress,seven of the GSK3 genes(HaSK11,HaSK12,HaSK13,HaSK32,HaSK33,HaSK41,and HaSK42)showed a substantial increase,whereas HaSK21 and HaSK23 had a sharp decline.This research is of great importance in understanding the abiotic resistance mechanism of sunflowers and developing new varieties with improved stress resistance.
文摘This paper reviews works on the dynamic analysis of flexible and rigid pavements under moving vehicles on the basis of continuum-based plane strain models and linear theories.The purpose of this review is to provide in-formation about the existing works on the subject,critically discuss them and make suggestions for further research.The reviewed papers are presented on the basis of the various models for pavement-vehicle systems and the various methods for dynamically analyzing these systems.Flexible pavements are modeled by a homogeneous or layered half-plane with isotropic or anisotropic and linear elastic,viscoelastic or poroelastic material behavior.Rigid pavements are modeled by a beam or plate on a homogeneous or layered half-plane with material properties like the ones for flexible pavements.The vehicles are modeled as concentrated or distributed over a finite area loads moving with constant or time dependent speed.The above pavement-vehicle models are dynamically analyzed by analytical,analytical/numerical or purely numerical methods working in the time or frequency domain.Representative examples are presented to illustrate the models and methods of analysis,demonstrate their merits and assess the effects of the various parameters on pavement response.The paper closes with con-clusions and suggestions for further research in the area.The significance of this research effort has to do with the presentation of the existing literature on the subject in a critical and easy to understand way with the aid of representative examples and the identification of new research areas.
文摘A more accurate estimation of stress-strain relationships for martensite and ferrite was developed, and the modified law of mixture was used to investigate the stress-strain partitioning of constituent phases in dual phase (DP) steels with two different martensite volume fractions. The results show that there exist great differences in the stress-strain contribution of martensite and ferrite to DP steel. The stress-strain partitioning coefficient is not constant in the whole strain range, but decreases with increasing the true strain of DP steel. The softening effect caused by the dilution of carbon concentration in martensite with the increase of martensite volume fraction has great influence on the strain contribution of martensite. The strain ratio of ferrite to martensite almost linearly increases with increasing the true strain of DP steel when the martensite volume fraction is 22%, because martensite always keeps elastic. But the strain ratio of ferrite to martensite varies indistinctively with the further increase in true strain of DP steel above 0.034 when the martensite volume fraction is 50%, because plastic deformation happens in martensite. The stress ratio ofmartensite to ferrite decreases monotonously with increasing the true strain of DP steel whether the martensite volume fraction is 22% or 50%.
基金supported by the Health and Humanities Research Center Project of Zigong City Key Research Base of Philosophy and Social Sciences(No.JKRWY22-26)。
文摘Objective:To understand the latent categories of perceived stress in colorectal cancer patients and analyze the characteristics of different categories of patients.Methods:A total of 255 colorectal cancer patients receiving treatment in the gastrointestinal surgery and oncology depar tments of a ter tiary Grade A hospital in Sichuan Province,from January 2023 to June 2023,were selected as the study subjects.General information questionnaire,Chinese version of the Perceived Stress Scale(CPSS),and Comprehensive Score Table for Patient-Repor ted Outcome Measures of Economic Toxicity(COST-PROM)were used for data collection.Results:Perceived stress in colorectal cancer patients was classified into 3 latent categories:C1“Low stress-stable type”(19.2%),C2“Moderate stress-uncontrolled type”(23.9%),and C3“High stress-anxious type”(56.9%).The average score of perceived stress was(34.07±5.08).Compared with C1 type,patients with a monthly household income of≤3000 RMB were more likely to belong to the C2 and C3 types(P<0.05),and patients without a stoma were less likely to belong to C3 type(P<0.05).Compared with C2 type,male patients were more likely to belong to C3 type(P<0.05),and patients without a stoma were less likely to belong to C3 type(P<0.05).Compared with C3 type,patients with higher economic toxicity scores were more likely to be classified into C1 and C2 types(P<0.05).Conclusions:Perceived stress in colorectal cancer patients exhibits distinct categorical features.Male gender,lower income,presence of a stoma,and higher economic toxicity are associated with higher levels of perceived stress in colorectal cancer patients.
基金funded by the Key Project of Clinical Specialty of Ministry of Public Health,No.2007-353
文摘The magnitude of tensile stress and tensile strain at an anastomosis site under physiological stress is an important factor for the success of anastomosis following suturing in peripheral nerve injury treatment. Sciatic nerves from fresh adult cadavers were used to create models of sciatic nerve injury. The denervated specimens underwent epineurial and perineurial suturing. The elastic modulus (40.96 + 2.59 MPa) and Poisson ratio (0.37 + 0.02) of the normal sciatic nerve were measured by strain electrical measurement. A resistance strain gauge was pasted on the front, back left, and right of the edge of the anastomosis site after suturing. Strain electrical measurement results showed that the stress and strain values of the sciatic nerve following perineurial suturing were lower than those following epineurial suturing. Scanning electron microscopy revealed that the sciatic nerve fibers were disordered following epineurial compared with perineurial suturing. These results indicate that the effect of perineurial suturing in sciatic nerve injury repair is better than that of epineurial suturing.
基金This project is supported by 863 Program of China (N0.2002AA331112)Doctoral Foundation of Northwestern Polytechnical University.
文摘The microstructure of surface peeling in finish rolled Cu-0.1Fe-0.03P sheetis analyzed by scanning electron microscope and energy dispersive spectroscope. Fe-rich areas ofdifferent contents are observed in the matrix. The stress distributions and strain characteristicsat the interface between Cu matrix and Fe particle are studied by elastic-plastic finite elementplane strain model. Larger Fe particles and higher deforming extent of finish rolling are attributedto the intense stress gradient and significant non-homogeneity equivalent strain at the interfaceand accelerate surface peeling of Cu-0.1Fe-0.03P lead frame sheet.
基金Project(2007DFR70070) supported by China-Russia Government-to-Government Scientific and Technical Cooperation Foundation
文摘The effect of strain hardening and strain softening behavior of flow stress changing with temperature on welding residual stress, plastic strain and welding distortion of ATN0 1-T4 aluminum alloy was studied by finite simulation method. The simulation results show that the weld seam undergoes strain hardening in the temperature range of 180-250 ℃, however, it exhibits strain softening at temperature above 250 ℃ during welding heating and cooling process. As a result, the strain hardening and strain softening effects counteract each other, introducing slightly influence on the welding residual stress, residual plastic strain and distortion. The welding longitudinal residual stress was determined by ultrasonic stress measurement method for the flat plates of A7N01-T4 aluminum alloy. The simulation results are well accordant with test ones.
文摘We studied the effect of loose tenon dimensions on stress and strain distributions in T-shaped mortise and loose tenon (M&amp;LT) furni-ture joints under uniaxial bending loads, and determined the effects of loose tenon length (30, 45, 60, and 90 mm) and loose tenon thickness (6 and 8 mm) on bending moment capacity of M&amp;LT joints constructed with polyvinyl acetate (PVAc) adhesive. Stress and strain distributions in joint elements were then estimated for each joint using ANSYS finite element (FE) software. The bending moment capacity of joints increased significantly with thickness and length of the tenon. Based on the FE analysis results, under uniaxial bending, the highest shear stress values were obtained in the middle parts of the tenon, while the highest shear elastic strain values were estimated in glue lines between the tenon sur-faces and walls of the mortise. Shear stress and shear elastic strain values in joint elements generally increased with tenon dimensions and corre-sponding bending moment capacities. There was consistency between predicted maximum shear stress values and failure modes of the joints.
基金Project supported by the National Natural Science Foundation of China (Grant No 90101004) and by the National Basic Research Program of China (Grant No G2000067102).
文摘In this paper, we perform systematic calculations of the stress and strain distributions in InAs/GaAs truncated pyramidal quantum dots (QDs) with different wetting layer (WL) thickness, using the finite element method (FEM). The stresses and strains are concentrated at the boundaries of the WL and QDs, are reduced gradually from the boundaries to the interior, and tend to a uniform state for the positions away from the boundaries. The maximal strain energy density occurs at the vicinity of the interface between the WL and the substrate. The stresses, strains and released strain energy are reduced gradually with increasing WL thickness. The above results show that a critical WL thickness may exist, and the stress and strain distributions can make the growth of QDs a growth of strained three-dimensional island when the WL thickness is above the critical value, and FEM can be applied to investigate such nanosystems, QDs, and the relevant results are supported by the experiments.
基金the Natural SciencesEngineering Research Council of Canadathe NATO Scientific Affairs Division
文摘Light beam deflections caused by stress or strain gradients are inves- tigated analytically and experimentally in homogeneous beam specimens which are subjected to a particular case of flexure with shear. This study is a generalization of the prior an alytical-experimental examination of strain-gradient light deflections produced in stressed plates, which had concentrated on the simplest case where in- formation of interest is collected along a line of symmetry of the stress field. Main purpose of the present investigation is to document the efficacy of the strain-gradient method in analysis of the general case of stress state. The most interesting stress state is that in a beam subjected to the Saint-Venant bending, where the transversal and the longitudinal axes of the beam are in pure shear. The obtained results are compared with the predictions of the developed analytical models and with the pre- dictions of Filon's stress function. The procedures of evaluating the photoelastic and material coefficients using strain-gradient techniques were tested positively.
文摘The plane structure of bars jointed to a rigid-body is a complex and universal structure.Some other structure of bars can be considered as its special cases. Many material have different stress-strain relation in tension and compression, generally the relation is nonlinear. In this paper,we use the constitutive model of linearly elastic and power hardening of strength difference to analyze plane structure of bars. The displacement method is used to derive the universal expression of calculating stress and strain. The nonlinear equations for computing displacements of the rigid-body has been given and general computing program has been worked out. This problem has been solved satisfactorily.
文摘In this paper, the stress-strain curve of material is fitted by polygonal line composed of three lines. According to the theory of proportional loading in elastoplasticity, we simplify the complete stress-strain relations, which are given by the increment theory of elastoplasticity. Thus, the finite element equation with the solution of displacement is derived. The assemblage elastoplastic stiffness matrix can be obtained by adding something to the elastic matrix, hence it will shorten the computing time. The determination of every loading increment follows the von Mises yield criteria. The iterative method is used in computation. It omits the redecomposition of the assemblage stiffness matrix and it will step further to shorten the computing time. Illustrations are given to the high-order element application departure from proportional loading, the computation of unloading fitting to the curve and the problem of load estimation.
文摘Estimation of in situ stresses based on back-analysis of measured stress changes and displacements has become an alternative to the direct stress measurement methods.In order to help users conduct own measurement and analysis,this paper presents in detail a field stress back-analysis approach directly from borehole strain changes measured during nearby underground excavation.Essential formulations in major steps and the procedure for the entire analysis process are provided to allow users to follow.The instrument for borehole strain change measurement can be the CSIR or CSIRO stress cells and other borehole strain cells that can measure strains on borehole walls.Strain changes corresponding to the stress changes at a borehole location are calculated in borehole environment.The stress changes due to nearby excavation can be calculated by an analytical model for a single circular opening and simulated by a numerical model for non-circular and multiple openings.These models are based on isotropic,homogeneous and linear elastic assumptions.The analysis of borehole strain changes is accomplished by multiple linear regression based on error minimization and an integrated process provides the best-fit solution directly to the in situ stresses.A statistical technique is adopted for screening outliers in the measurement data,checking measurement compatibility and evaluating the reliability of analysis results.An application example is included to demonstrate the practical application and the analysis procedure.
文摘The design temperature of high plutonium concentration ZPPR fuel plates is 600°C. Cladding integrity of the 304 L stainless steel cladding is a significant concern with this fuel since even small holes can lead to substantial fuel degradation. Since the fuel has a higher coefficient of thermal expansion than the cladding, an investigation of the stress induced in the cladding due to the differential thermal expansion of fuel and cladding up to the design temperature was conducted. Small holes in the cladding envelope would be expected to lead to the fuel hydriding and oxidizing into a powder over a long period of time. This is the same type of chemical reaction chain that exists in the degradation of the high uranium concentration ZPPR fuel. Unfortunately, the uranium fuel was designed with vents which allowed this degradation to occur. The Pu cladding is sealed so only fuel with damaged cladding would be subject to this damage. The thermal stresses that can be developed in the fuel cladding have been calculated in this paper and compared to the ultimate tensile stress of the cladding. The conclusion is drawn that thermal stresses cannot induce holes in the cladding even for the highest storage temperatures predicted in calculations (292°C). In fact, thermal stress cannot cause cladding failure as long as the fuel temperatures are below the design limit of 600°C (1112°F).
文摘A new method was denonstrated to determine stress in a single crystal for multicrystal material and this new method could be specially applied for any symmetric crystalline systems. The strain tensor e was determined by the change of the metric tensor G before the initial state and after the deformed state in the crystal reference system. Then stress tensor at grain scale was calculated by the HOOK's law. The stress evaluations were carried out in coarse grains of a thin galvanized coating on a steel substrate during tensile loading. This makes it possible to link the microstructure evolution to the elastic heterogeneity at grain scale or between the grains.
文摘This research presents an experimental study of analysis of stress strain state SSS of X-60 pipe weld joints employing magnetic anisotropy indicator of mechanical stresses Stress Vision (IMS) using of “before and after” comparison approach taking readings on pipe base metal, weld area and heat affected zone (HAZ) before and after hydrotest. Test results were compared with X-ray testing results for welded joints and with metallographic testing. Test results demonstrate the relevance of applied test conditions and redistribution of residual stresses. A new equation was established for estimating the residual (technological) and operating stresses in other pipelines with a tolerance of 15% in the field of elastic deformation (up to the yield point), according to Hooke law.
文摘Engineering members often include cutouts.Although the structural integrity of such members can be highly influenced by associated stresses,determining them may be very challenging for finite shapes operating in an industrial environment.This is particularly so if the loading is not well known,a common occurrence in practical situations.While photomechanical methods can be effective,they necessitate optical access to the component,something which is also often unavailable.Recognizing the above,this paper demonstrates ability to determine the complete stresses throughout a perforated tensile plate using only aligned,single-element strain gages rather than multi-element rosettes.Although reliability is verified using finite elements,an objective of the technique is for situations when finite element methods are not feasible,e.g.,the loading is inadequately known.The approach is applicable to members fabricated from isotropic,orthotropic or functionally-graded materials and is not restricted to a particular shape,cutout arrangement or loading condition.