Positive correlations between the health locus of control and self-management behaviors in hemodialysis patients in Xiamen

Objective:To investigate the association between the health locus of control and selfmanagement behaviors in patients receiving hemodialysis.Methods:Patients receiving hemodialysis in Xiamen,Fujian province,from December 2014 to March 2015 answered the Chinese version of the Multidimensional Health Locus of Control scale and the self-management behavior questionnaire.Results:The participants in this study indicated that they believed others exerted more control over their health than themselves or chance.In addition,the majority of participants had a medium to low level of self-management behaviors.Positive correlations were also observed between a participant's health locus of control and their level of selfmanagement behaviors.Internal health locus of control and external(others)health locus of control were significant predictors of self-management behaviors controlling for the effect of payment method.Conclusion:The results of this study provided evidence that there is a strong relationship between the health locus of control and self-management behaviors in hemodialysis patients.This study provides important information for medical professionals as they design strategies to educate hemodialysis patients on their health locus of control and selfmanagement behaviors.

The status quo and influence of self-management behaviors in convalescent stroke patients

Objective： The aims of this study were to investigate the status quo of self-management behaviors in stroke patients at the recovery stage and to explore its influencing factors.Methods： A total of 440 hospitalized convalescent stroke patients were recruited and investigated using the Basic Situation Questionnaire, Self-management Behavior Scale of Stroke, Stroke Prevention Knowledge Questionnaire and Social Support Rating Scale.Results： The mean self-management behavior score was （151.95±23.58）, and dimensions in descending order were as follows： dietary management, drug safety management, social function and interpersonal relationships, life management, emotion management, rehabilitation exercise management and disease management. Five regional self-management behavior scores were statistically significant, and the scores from Minnan and Minzhong of the Fujian province, China, were higher than the others. Gender, age, family income and self-management behavior were significantly correlated （P〈0.05）; educational level, stroke knowledge level, social support level and self-management behavior were positively correlated, and the difference was statistically significant （P〈0.01）. Conclusions： The overall self-management level of convalescent stroke patients should be improved to strengthen health education; focus on the educational level, which is relatively low; strengthen the social support system of patients; stimulate the enthusiasm and initiative of self-management disease patients to promote disease rehabilitation and improve the quality of life.

Awareness, self-management behaviors, health literacy and kidney function relationships in specialty practice

AIM To determine the relationship between chronic kidney disease(CKD) awareness(CKD-A), self-management behaviors(CKD-SMB) knowledge, performance of CKDSMBs, health literacy(HL) and kidney function. METHODS Participants were eligible patients attending an outpatient nephrology clinic. Participants were administered: Newest Vital Sign to measure HL, CKD self-managementknowledge tool(CKD-SMKT) to assess knowledge, past performance of CKD-SMB, CKD-A. Estimated GFR(e GFR) was determined using the MDRD-4 equation. Duration of clinic participation and CKD cause were extracted from medical charts. RESULTS One-hundred-fifty patients participated in the study. e GFRs ranged from 17-152 m L/min per 1.73 m2. Majority(83%) of respondents had stage 3 or 4 CKD, low HL(63%), and were CKD aware(88%). Approximately 40%(10/25) of patients in stages 1 and 2 and 6.4%(8/125) in stages 3 and 4 were unaware of their CKD. CKD-A differed with stage(P < 0.001) but not by HL level, duration of clinic participation, or CKD cause. Majority of respondents(≥ 90%) correctly answered one or more CKD-SMKT items. Knowledge of one behavior, "controlling blood pressure" differed significantly by CKD-A. CKD-A was associated with past performance of two CKD-SMBs, "controlling blood pressure"(P = 0.02), and "keeping healthy body weight"(P = 0.01). Adjusted multivariate analyses between CKD-A and:(1) HL; and(2) CKD-SMB knowledge were nonsignificant. However, there was a significant relationship between CKD-A and kidney function after controlling for demographics, HL, and CKD-SMB(P < 0.05). CONCLUSION CKD-A is not associated with HL, or better CKD-SMBs. CKD-A is significantly associated with kidney function and substantially lower e GFR, suggesting the need for focused patient education in CKD stages 1.

Self-Management Behaviors of Patients with Hypertension in Daily Life

Background: In a rapidly aging Japanese society, the number of patients with hypertension has seen a steady increase. The basic treatments for hypertension are maintaining blood pressure through medication and preventing complications. It is important for patients with hypertension to perform self-management. This improves their lifestyle while controlling their blood pressure to prevent complications and maintain good health. Purpose: This study aimed to examine the actual self-management behavior ability of patients with hypertension and to clarify the factors involved in their self-management behavior. Methods: A total of 150 patients with hypertension were included in this study. The following data were obtained from the patients as background information: sex, age, years with disease, whether they are receiving antihypertensive agents, type of antihypertensive agent, blood test data, heart thoracic ratio, left ventricular ejection fraction, pulse wave, pulse wave velocity, and height. The levels of self-management skills of the patients were also assessed using the “Instrument to Measure the Self-care of patients with Hypertension” developed by Tsuboi et al. Results: The associations among self-management behaviors in daily life, such as diet, exercise, stress, medication, alcohol intake, and smoking, were analyzed in patients with hypertension. The subjects were classified into the following three groups: aged 65 years or below (Group A), early stage elderly individuals (Group B), and late-stage elderly individuals aged 75 years or over (Group C). The results showed that the subjects in Group C had higher self-management scores for diet, exercise, stress, medication, and drinking than the subjects in the other two groups. The scores of smoking and self-management of the subjects in Group A were high but their other self-management scores were low. All the subjects were taking between 1 to 3 types of oral antihypertensive drugs. The rate of achievement of the target blood pressure was 50% or more in all the three groups. However, the pulse wave velocity was high in all the three groups. Conclusion: The results indicate that the risk of developing disorders of the brain and cardiovascular system is high in all the three groups, owing to the high degree of arteriosclerosis. Therefore, increasing the number of nursing interventions is expected to reduce blood pressure, maintain and promote self-management behavior in daily life, and prevent the onset of complications. The results suggest that nursing interventions involving lifestyle guidance for improving the self-management skills of patients are urgently needed by patients under 65 years of age.

Microstructures and micromechanical behaviors of high -entropy alloys investigated by synchrotron X-ray and neutron diffraction techniques: A review

High-entropy alloys(HEAs)possess outstanding features such as corrosion resistance,irradiation resistance,and good mechan-ical properties.A few HEAs have found applications in the fields of aerospace and defense.Extensive studies on the deformation mech-anisms of HEAs can guide microstructure control and toughness design,which is vital for understanding and studying state-of-the-art structural materials.Synchrotron X-ray and neutron diffraction are necessary techniques for materials science research,especially for in situ coupling of physical/chemical fields and for resolving macro/microcrystallographic information on materials.Recently,several re-searchers have applied synchrotron X-ray and neutron diffraction methods to study the deformation mechanisms,phase transformations,stress behaviors,and in situ processes of HEAs,such as variable-temperature,high-pressure,and hydrogenation processes.In this review,the principles and development of synchrotron X-ray and neutron diffraction are presented,and their applications in the deformation mechanisms of HEAs are discussed.The factors that influence the deformation mechanisms of HEAs are also outlined.This review fo-cuses on the microstructures and micromechanical behaviors during tension/compression or creep/fatigue deformation and the application of synchrotron X-ray and neutron diffraction methods to the characterization of dislocations,stacking faults,twins,phases,and intergrain/interphase stress changes.Perspectives on future developments of synchrotron X-ray and neutron diffraction and on research directions on the deformation mechanisms of novel metals are discussed.

Snap-through behaviors and nonlinear vibrations of a bistable composite laminated cantilever shell:an experimental and numerical study

The snap-through behaviors and nonlinear vibrations are investigated for a bistable composite laminated cantilever shell subjected to transversal foundation excitation based on experimental and theoretical approaches.An improved experimental specimen is designed in order to satisfy the cantilever support boundary condition,which is composed of an asymmetric region and a symmetric region.The symmetric region of the experimental specimen is entirely clamped,which is rigidly connected to an electromagnetic shaker,while the asymmetric region remains free of constraint.Different motion paths are realized for the bistable cantilever shell by changing the input signal levels of the electromagnetic shaker,and the displacement responses of the shell are collected by the laser displacement sensors.The numerical simulation is conducted based on the established theoretical model of the bistable composite laminated cantilever shell,and an off-axis three-dimensional dynamic snap-through domain is obtained.The numerical solutions are in good agreement with the experimental results.The nonlinear stiffness characteristics,dynamic snap-through domain,and chaos and bifurcation behaviors of the shell are quantitatively analyzed.Due to the asymmetry of the boundary condition and the shell,the upper stable-state of the shell exhibits an obvious soft spring stiffness characteristic,and the lower stable-state shows a linear stiffness characteristic of the shell.

Impact of parenting styles on preschoolers’behaviors

In this editorial,I comment on the article“Association of preschool children behavior and emotional problems with the parenting behavior of both parents”which was published in the latest issue of“World Journal of Clinical Cases”that demonstrates the prevalence of behavioral disorders in preschool children.Therefore I am focused on parenting which is the most effective factor shown to affect the development and continuity of these behaviors.The management of child behavior problems is crucial.Children in early ages,especially preschoolers who are in the first 5 years of life,are influenced by dramatic changes in various aspects of development,such as social,emotional,and physical.Also,children experience many changes linked to different developmental tasks,such as discovering themselves,getting new friendships,and adapting to a new environment.In this period,parents have a critical role in supporting child development.If parents do not manage and overcome their child’s misbehavior,it could be transformed into psychosocial problems in adulthood.Parenting is the most powerful predictor in the social development of preschool children.Several studies have shown that to reduce the child’s emotional and behavioral problems,a warm relationship between parents and children is needed.In addition,recent studies have demonstrated significant relationships between family regulation factors and parenting,as well as with child behaviors.

Elastic-viscoplastic behaviors of polymer-blend geocell sheets:Numerical and experimental investigations

Polymer-blend geocell sheets(PBGS)have been developed as substitute materials for manufacturing geocells.Various attempts have been made to test and predict the behaviors of commonly used geogrids,geotextiles,geomembranes,and geocells.However,the elastic-viscoplastic behaviors of novel-developed geocell sheets are still poorly understood.Therefore,this paper investigates the elastic-viscoplastic behaviors of PBGS to gain a comprehensive understanding of their mechanical properties.Furthermore,the tensile load-strain history under various loading conditions is simulated by numerical calculation for widespread utilization.To achieve this goal,monotonic loading tests,short-term creep and stress relaxation tests,and multi-load-path tests(also known as arbitrary loading history tests)are performed using a universal testing machine.The results are simulated using the nonlinear three-component(NLTC)model,which consists of three nonlinear components,i.e.a hypo-elastic component,a nonlinear inviscid component,and a nonlinear viscid component.The experimental and numerical results demonstrate that PBGS exhibit significant elastic-viscoplastic behavior that can be accurately predicted by the NLTC model.Moreover,the tensile strain rates significantly influence the tensile load,with higher strain rates resulting in increased tensile loads and more linear load-strain curves.Also,parametric analysis of the rheological characteristics reveals that the initial tensile strain rates have negligible impact on the results.The rate-sensitivity coefficient of PBGS is approximately 0.163,which falls within the typical range observed in most geosynthetics.

Comparison of electrochemical behaviors of Ti-5Al-2Sn-4Zr-4Mo-2Cr-1Fe and Ti-6Al-4V titanium alloys in NaNO_(3) solution

The Ti-5Al-2Sn-4Zr-4Mo-2Cr-1Fe(β-CEZ)alloy is considered as a potential structural material in the aviation industry due to its outstanding strength and corrosion resistance.Electrochemical machining(ECM)is an efficient and low-cost technology for manufacturing theβ-CEZ alloy.In ECM,the machining parameter selection and tool design are based on the electrochemical dissolution behavior of the materials.In this study,the electrochemical dissolution behaviors of theβ-CEZ and Ti-6Al-4V(TC4)alloys in NaNO3solution are discussed.The open circuit potential(OCP),Tafel polarization,potentiodynamic polarization,electrochemical impedance spectroscopy(EIS),and current efficiency curves of theβ-CEZ and TC4 alloys are analyzed.The results show that,compared to the TC4 alloy,the passivation film structure is denser and the charge transfer resistance in the dissolution process is greater for theβ-CEZ alloy.Moreover,the dissolved surface morphology of the two titanium-based alloys under different current densities are analyzed.Under low current densities,theβ-CEZ alloy surface comprises dissolution pits and dissolved products,while the TC4 alloy surface comprises a porous honeycomb structure.Under high current densities,the surface waviness of both the alloys improves and the TC4 alloy surface is flatter and smoother than theβ-CEZ alloy surface.Finally,the electrochemical dissolution models ofβ-CEZ and TC4 alloys are proposed.

Quantitative assessment of self-management in patients with nonalcoholic fatty liver disease: An unmet clinical need

In this editorial we comment on the article titled“Establishment and validation of an adherence prediction system for lifestyle interventions in non-alcoholic fatty liver disease”by Zeng et al published in a recent issue of the World Journal of Gastroenterology.Non-alcoholic fatty liver disease(NAFLD)represents one of the current challenges in hepatology and public health,due to its continuous growing prevalence and the rising incidence of NAFLD-related fibrosis,non-alcoholic steatohepatitis and cirrhosis.The only effective therapeutic strategy for this dis-ease is represented by encouraging patients to improve their lifestyle through the modification of dietary intake and increased physical exercise,but the effective application of such modifications is often limited by various factors such as lack of information,psychological barriers or poor social support.While poor adherence to a healthy lifestyle can be decisive in determining the clinical outcome,in daily practice there is a lack of quantitative instruments aimed at identifying patients with the lowest adherence to lifestyle changes and higher risk of disease progre-ssion in the course of follow-up.In this article,Zeng et al propose a quantitative scale to assess the grade of adherence of patients with NAFLD to hea-lthy lifestyle intervention,called the Exercise and Diet Adherence Scale(EDAS).This scale,consisting of 33 items divided into 6 dimensions which relates to six subjective aspects in the self-management of NAFLD,has shown a good correlation with the identification of the sub-cohort of patients with the highest reduction in caloric intake,increase in physical exercise,probability of a reduction in liver stiffness measurement and alanine aminotransferase levels.The cor-relation among clinical outcomes and specific dimensions of this scale also highlights the pivotal role of a good and confidential doctor-patient relationship and of an effective communication.There is an urgent need for practical and effective instruments to assess the grade of self-management of NAFLD patients,together with the development of multidisciplinary teams with the aim of applying structured behavioral interventions.

Influencing factors of self-management ability among dry eye patients in west China

AIM:To investigate the current situation and influencing factors of self-management ability in dry eye patients in west China.METHODS:A total of 265 patients clinically diagnosed with dry eye received a convenience survey questionnaire at West China Hospital of Sichuan University.All participants completed the rating scale of health self-management skill for adults(AHSMSRS),Huaxi Emotional-Distress Index(HEI),e-health literacy scale(e-HEALS)and Brief Illness Perception Questionnaire(Brief-IPQ).A generalized linear model was employed to establish a multivariate linear model with demographic data,psychological state,e-HEALS,and illness perception as independent variables and health selfmanagement skill score as the dependent variable.RESULTS:The mean score for health self-management skill was 165.58±15.79.Multivariate analysis revealed that advanced age,better illness perception and improved psychological state were associated with better health selfmanagement ability among dry eye patients.Furthermore,the health self-management ability of patients with a disease duration less than 1y was found to be higher compared to those with a disease duration exceeding 1y.CONCLUSION:The health self-management ability of dry eye patients in west China is relatively high.Age,duration of disease,illness perception and psychological state are the influencing factors on the health selfmanagement ability of dry eye patients.

Effect of Diabetes Self-Management Education on Glycaemic Control in Sudanese Adults with Type 2 Diabetes

Research Background: The high prevalence of diabetes in Sudan, estimated at 16%, highlights the importance of effective health education in diabetes management. Diabetes self-management education has been identified as a crucial tool in enhancing the knowledge, attitudes, and abilities necessary for self-management among individuals with diabetes. Aim: To assess the impact of diabetes self-management education on medication adherence and glycemic control in Sudanese adults with type 2 diabetes before and 3 months after the DSME intervention. Method: The study was conducted in Sudan between September 2022 and March 2023, it was an interventional, one-group, pre- and post-test study that aimed to assess the impact of diabetes self-management education (DSME) on medication adherence and diabetes control in Sudanese adults with type 2 diabetes. The research was conducted in primary health care centers in six cities in Sudan and involved 244 participants. The data entry and statistical analysis were conducted using the Statistical Package for Social Sciences version 27.0. A paired t test was used for analysis. Results: The study included 244 participants, 67% of whom were males. The age mean ± SD was 48.6 ± 9.3 years, and 85.3% of participants were married. Age at onset of diabetes mean ± SD was 40.60 ± 7.81 years;44.6% had diabetes for less than 5 years;and 84.1% had a positive family history of diabetes mellitus. The levels of poor, low, and partial adherence to medication decreased by 8.2%, 4%, and 20.6%, respectively, after the intervention. The levels of good and high medication regime adherence increased by 13% and 19.8%, respectively;BMI decreased by 1.1 ± 0.73 kg/m2 (p = 0.005). The fasting blood sugar decreased by 69 ± 32.9 mg/dl (p = 0.049), and the glycated hemoglobin decreased by 1.21 ± 0.28% (p = 0.001). Conclusions: The findings of this study reinforce the importance of patient education in improving glycemic control and enhancing self-management behaviors. Patient education plays a critical role in enhancing glycemic control and self-management behaviors. It is essential for healthcare providers to adopt a patient-centered approach, taking into account the individual's beliefs, attitudes, and knowledge about their illness and treatment. Overcoming these challenges necessitates a comprehensive approach, including enhancing healthcare professionals’ knowledge and communication skills, offering accessible and culturally sensitive diabetes education programs, and addressing barriers to resources and support for self-management.

The Impact of Social Media on Dietary Behaviors and Body Image of College Students: A Qualitative Approach

Background: The use of social media platforms for health and nutrition information has become popular among college students. Although social media made information readily accessible in different formats, nutritional misinformation promoted by influencers and non-experts caused negative impact on diet behavior and perception of body image. Previous research indicated that extensive use of social media was positively linked to disordered eating behaviors. Social media platforms like Facebook and Instagram that allow users to follow celebrities intensified exposure to influencers’ messages and images and resulted in negative moods and body dissatisfaction. Objective: This paper aims to explore the impact of social media on college students’ dietary behaviors and body image. Participants: 18 undergraduate students from a public university in the Southern United States were recruited through a mass email. Methods: A cross-sectional qualitative study of three focus groups was conducted. The focus groups were based on guiding open-ended questions. Atlas.ti was used to code and analyze the data using inductive and deductive codes. Results: Three main themes were identified. The conditions theme included elements that explain why and how social media influences the participants’ actions. The actions theme included eating behavior, physical activity, and dietary supplement intake. The consequences theme describes anticipated or actual outcomes of actions such as body image and ideal weight. Conclusions: Social media has had a negative influence on diet behaviors and a positive influence on physical activity. Evidence-based nutrition and weight management information is needed to thwart potential misinformation.

Xylooligosaccharides Alleviate Inflammatory Dermatoses and Related Depression-Like Behaviors in Atopic Dermatitis Mice Induced by 2,4-Dinitrofluorobenzene

Objective:To investigate the influence of xylooligosaccharides on skin inflammation,behavioral characteristics,neurotransmitters,and gut flora in a mouse model of atopic dermatitis(AD)induced by 2,4-dinitrofluorobenzene(DNFB).Methods:The AD mouse model was created by administration of DNFB for 14 consecutive days.The scoring atopic dermatitis index,enzyme-linked immunosorbent assay(ELISA),histopathology,and immunohistochemical analyses were used to assess inflammation and depression-like behaviors.Furthermore,high-throughput 16S rRNA gene sequencing was used to determine the composition of fecal microbiota.Results:Xylooligosaccharides treatment reduced the number of scratches and skin thickness,mast cell infiltration and the levels of immunoglobulin(Ig)E and T-helper cytokines compared with the AD model group.Meanwhile,xylooligosaccharides treatment reduced the immobility time of mice in the forced swimming test and increased the total movement distance and movement distance in the center area in the open-field test.Furthermore,5-hydroxytryptamine and dopamine expression in the brain was increased following xylooligosaccharides treatment.Using network pharmacology,Gene Ontology analysis showed that the targets were mainly enriched in phosphatase binding and the regulation of leukocyte differentiation,which ameliorated AD mainly through the hypoxia inducible factor-1 and phosphatidylinositide 3-kinase-protein kinase B pathways.16S rRNA gene sequencing,diversity indices,and gut microbial taxonomic composition analysis showed DNFB-induced changes in intestinal microbiota diversity in AD mice.Comparative analysis indicated that xylooligosaccharides intake improved the gut microbiome by dramatically enhancing the concentration of Lactobacillus while decreasing the concentration of Bacteroides in mice.Conclusion:Xylooligosaccharides reduce inflammatory dermatosis and related depression-like behaviors via regulating intestinal homeostasis,having medicinal value as a nutritional and functional ingredient.

MD Simulation of Diffusion Behaviors in Collision Welding Processes of Al-Cu, Al-Al, Cu-Cu

To investigate the effects of material combinations and velocity conditions on atomic diffusion behavior near collision interfaces,this study simulates the atomic diffusion behavior near collision interfaces in Cu-Al,Al-Al and Cu-Cu combinations fabricated through collision welding using molecular dynamic(MD)simulation.The atomic diffusion behaviors are compared between similar metal combinations(Al-Al,Cu-Cu)and dissimilar metal combinations(Al-Cu).By combining the simulation results and classical diffusion theory,the diffusion coefficients for similar and dissimilar metal material combinations under different velocity conditions are obtained.The effects of material combinations and collision velocity on diffusion behaviors are also discussed.The diffusion behaviors of dissimilar material combinations strongly depend on the transverse velocity,whereas those of the similar material combinations are more dependent on the longitudinal velocity.These findings can provide guidance for optimizing welding parameters.

Dietary L-proline supplementation ameliorates autism-like behaviors and modulates gut microbiota in the valproic acid-induced mouse model of autism spectrum disorder

The effective intervention strategy for autism spectrum disorder(ASD)are currently limited.Herein,we attempted to evaluate the potential of L-proline(Pro),a multifunctional amino acid,in ameliorating autismlike behaviors and clarify the molecular mechanisms involved by using the typical valproic acid(VPA)-induced mouse model of ASD.Pro significantly attenuates repetitive behaviors and social dysfunction in ASD mice.The correlation analysis revealed that the beneficial effects of Pro on autism-like behaviors are related to the modulation of gut microbiota structure and composition.The histological analysis revealed that Pro could reverse the decrease of Nissl-positive cells in the prefrontal cortex(PFC)induced by VPA exposure.RNA sequencing demonstrated that Pro can also alter the PFC transcriptomic profile distinguished by the regulation of genes involved in Parkinson disease,neuroactive ligand-receptor interaction,oxidative phosphorylation,and mitogen activated protein kinase signaling pathway.Overall,dietary Pro supplementation may be a promising intervention strategy for ASD.

Liquefaction and post-liquefaction behaviors of sands affected by immersion-induced degradation of crushed mudstone

A series of undrained triaxial tests was conducted to investigate the effect of crushed mudstone with the immersion-induced degradation on the liquefaction and post-liquefaction properties,and the undrained shearing behavior without precedent cyclic-loading histories of sands containing crushed mudstone.The tested materials with a main particle diameter of 2-0.85 mm were prepared by mixing sands and crushed mudstone to reach the prescribed mudstone content defined by dry mass ranging from 0% to 50%.The mixtures were subjected to immersion under a certain stress level and were subsequently tested.In addition,one-dimensional compression tests were also supplementally performed to visually observe the immersion-induced degradation of crushed mudstone.The test results mainly showed that: (1) the liquefaction resistance,the post-liquefaction undrained strength,and the undrained strength without a precedent cyclic-loading history decreased significantly with increasing mudstone content,M c ,up to 20%;(2) even a small amount of crushed mudstone affected these strengths;(3) the above-mentioned large reductions in the strengths were attributed to the immersion-induced degradation of crushed mudstone;(4) at M_(c) >20%,the liquefaction resistance increased while the significant increase in the undrained static strengths with and without precedent cyclic-loading histories was not observed;and (5) the increase in the liquefaction resistance at M_(c) >20% may have been attributed to both the gradual increase in the plasticity and the formation of the soil aggregates among deteriorated crushed mudstone,while the increase in the specimen density did not play an important role in such behavior.

Finite Element Simulations on Failure Behaviors of Granular Materials with Microstructures Using a Micromechanics-Based Cosserat Elastoplastic Model

This paper presents a micromechanics-based Cosserat continuum model for microstructured granular materials.By utilizing this model,the macroscopic constitutive parameters of granular materials with different microstructures are expressed as sums of microstructural information.The microstructures under consideration can be classified into three categories:a medium-dense microstructure,a dense microstructure consisting of one-sized particles,and a dense microstructure consisting of two-sized particles.Subsequently,the Cosserat elastoplastic model,along with its finite element formulation,is derived using the extended Drucker-Prager yield criteria.To investigate failure behaviors,numerical simulations of granular materials with different microstructures are conducted using the ABAQUS User Element(UEL)interface.It demonstrates the capacity of the proposed model to simulate the phenomena of strain-softening and strain localization.The study investigates the influence of microscopic parameters,including contact stiffness parameters and characteristic length,on the failure behaviors of granularmaterials withmicrostructures.Additionally,the study examines themesh independence of the presented model and establishes its relationship with the characteristic length.A comparison is made between finite element simulations and discrete element simulations for a medium-dense microstructure,revealing a good agreement in results during the elastic stage.Somemacroscopic parameters describing plasticity are shown to be partially related to microscopic factors such as confining pressure and size of the representative volume element.

Thermally-induced cracking behaviors of coal reservoirs subjected to cryogenic liquid nitrogen shock

The benefits of using cryogenic liquid nitrogen shock to enhance coal permeability have been confirmed from experimental perspectives.In this paper,we develop a fully coupled thermo-elastic model in combination with the strain-based isotropic damage theory to uncover the cooling-dominated cracking behaviors through three typical cases,i.e.coal reservoirs containing a wellbore,a primary fracture,and a natural fracture network,respectively.The progressive cracking processes,from thermal fracture initiation,propagation or cessation,deflection,bifurcation to multi-fracture interactions,can be well captured by the numerical model.It is observed that two hierarchical levels of thermal fractures are formed,in which the number of shorter thermal fractures consistently exceeds that of the longer ones.The effects of coal properties related to thermal stress levels and thermal diffusivity on the fracture morphology are quantified by the fracture fractal dimension and the statistical fracture number.The induced fracture morphology is most sensitive to changes in the elastic modulus and thermal expansion coefficient,both of which dominate the complexity of the fracture networks.Coal reservoir candidates with preferred thermal-mechanical properties are also recommended for improving the stimulation effect.Further findings are that there exists a critical injection temperature and a critical in-situ stress difference,above which no thermal fractures would be formed.Preexisting natural fractures with higher density and preferred orientations are also essential for the formation of complex fracture networks.The obtained results can provide some theoretical support for cryogenic fracturing design in coal reservoirs.

Integrating linear and nonlinear models to assess the built environment’s impact on older adults’behaviors in China

China is experiencing rapid population aging.The one contributing factor affecting senior citizens’lives is the disconnect between the built environment in urban and rural areas and the behavioral preferences of older adults.However,research on the relation between the built environment and the behavior of older individuals has been limited.Thus,this paper uses the most recent health tracking data on factors influencing aging in China released in 2020(China Senior Health Survey Tracking Survey).Applying traditional regression,least absolute shrinkage and selection operator regression,and two decision tree optimization models from machine learning,a comprehensive comparative study is carried out to investigate the correlation between the built environment and the physical activity,dietary habits,and social interactions of older age groups.The findings reveal that built environment variables most significantly impact physical activity,accounting for 52.525%,followed by social interaction behaviors at 50.202%and dietary intake at 47.991%.Furthermore,the authors identify population density and greenness rate as the built environment factors having considerable effects on the behavior of older adults.Thus,this study establishes a theoretical foundation for developing age-friendly community environments for older adults.