Mechanical Response Research Articles

Mechanical Behavior of 3D-Printed Zig-Zag Honeycomb Structures Made of BASF Ultrafuse 316L

The aim of this study is to determine the mechanical behavior of 2D honeycomb cellular structures with deformation initiators subject to quasi-static compression testing. Two different loading directions were studied: in-plane (IP) and out-of-plane (OP). The deformation initiators sought to stabilize the mechanical response by decreasing the initial peak force in the case of OP loading. The samples for testing were made using stainless steel 316L that was 3D-printed using material extrusion (MEX). The method enables fabrication of structures with high mechanical strength and ductility. The findings of the quasi-static compression testing showed that the additional deformation initiators were able to significantly reduce the orthotropy in the mechanical response of honeycomb cellular structures.

Dynamic Analysis for Enhancing Urban Resilience Against Public Health Emergencies of International Concern

The frequent occurrence of Public Health Emergencies of International Concern (PHEIC) has posed significant challenges to urban public health, economic, and social systems, exposing gaps in urban resilience. This study developed a dynamic urban resilience assessment framework against PHEIC based on the system dynamics method, integrating index analysis and the SEIR (susceptible–exposed–infectious–recovered) epidemiological model to investigate the interactions and dynamic evolution of urban subsystems in New York, Hong Kong, and Nanjing during the COVID-19 epidemic. The findings revealed significant differences in the response mechanisms and recovery capacities across subsystems. For example, the stringent lockdowns policy in New York curbed virus spread and heavily impacted economic activities; the “close to Dynamic zero of COVID-19” policy in Hong Kong demonstrated stronger resilience in balancing public health and economic recovery; the dynamic control measures in Nanjing China allowed for the rapid restoration of urban functions with minimal resilience fluctuations. Although strict control measures can effectively suppress disease spread, they can have profound economic and social impacts. More scientific strategies, such as those seen in Hong Kong and Nanjing, offer a more balanced approach to managing both epidemic control and urban function recovery, providing key insights for future PHEIC response strategies.

A biomathematical model of SARS-CoV-2 in Syrian hamsters

When infected with SARS-CoV-2, Syrian hamsters (Mesocricetus auratus) develop moderate disease severity presenting key features of human COVID-19. We here develop a biomathematical model of the disease course by translating known biological mechanisms of virus-host interactions and immune responses into ordinary differential equations. We explicitly describe the dynamics of virus population, affected alveolar epithelial cells, and involved relevant immune cells comprising for example CD4+ T cells, CD8+ T cells, macrophages, natural killer cells and B cells. We also describe the humoral response dynamics of neutralising antibodies and major regulatory cytokines including CCL8 and CXCL10. The model is developed and parametrized based on experimental data collected at days 2, 3, 5, and 14 post infection. Pulmonary cell composition and their transcriptional profiles were obtained by lung single-cell RNA (scRNA) sequencing analysis. Parametrization of the model resulted in a good agreement of model and data. The model can be used to predict, for example, the time course of the virus population, immune cell dynamics, antibody production and regeneration of alveolar cells for different therapy scenarios or after multiple-infection events. We aim to translate this model to the human situation in the future.

Rhizobacteria Enterobacter sp. LHB11 and Bacillus sp. PIXIE Induced Systemic Tolerance Against Drought Stress in Tomato (Solanum lycopersicum)

Plant growth-promoting rhizobacteria (PGPR) induce changes in the plant metabolism, improving plant growth under drought stress conditions by employing different mechanisms of interaction. In this study, two bacterial strains (Enterobacter sp. LHB11 and Bacillus sp. PIXIE) were evaluated in vitro regarding their PGPR traits, including the ACC-Deaminase enzyme activity. Both PGPR strains produced indole acetic acid (40.65–75.81 µg−1mL−1), exopolysaccharides (39.23–40.20 µg eq CR mL−1), proline (61.5–106.1 mM), and volatile organic compounds. Furthermore, both solubilized phosphate (1.15–1.53 ratio, halo/colony) and fixed the atmospheric nitrogen. Only LHB11 showed ACC-Deaminase activity. Furthermore, both strains tolerated osmotic stress induced in liquid media with up to 20% of Polyethylene glycol-6000. In a drought stress pot experiment, both strains were applied to tomato roots, exposed to normal irrigation (100%) and drought stress (decreasing irrigation by 50%). The inoculation of both strains improved the plant growth parameters under stress conditions significantly, e.g., the root dry weight (+41.0–43.4%), while the proline content decreased to a level similar to the unstressed control. In addition, strain inoculation increased the total phenolic content and the antioxidant capacity measured as the inhibitions of the ABTS radical and as the reduction in ferric ions and increased the catalase and ascorbate peroxidase enzyme activity. The bacterial contribution to the changes in biochemical parameters is higher than in morphological parameters. At the same time, the strains modulate specific parameters depending on the stress condition, e.g., ABTS, catalase activity, and proline content. In conclusion, both strains Induced Systemic Tolerance (IST), regardless of their capacity to use the ACC-Deaminase mechanism, by modulating several mechanisms of plant response to drought stress. Our results showcase the relevance of considering the orchestration of several plant response mechanisms in order to fully assess the potential and efficiency of the plant–PGPR interaction under drought stress.

Penerapan Restorative Justice dalam Kasus Kekerasan Domestik di Indonesia: Studi Empiris di Wilayah Perkotaan dan Pedesaan

Domestic violence is a critical issue affecting many individuals and families in Indonesia, with varied impacts across urban and rural areas. This study examines the implementation of the Restorative Justice approach in resolving domestic violence cases in these contexts and identifies factors influencing its effectiveness. Using a mixed-methods approach, the research combines quantitative analysis through surveys and qualitative insights from in-depth interviews. Data were collected from 300 respondents, including victims, offenders, and mediators, from urban and rural settings, alongside interviews with key stakeholders. The findings reveal significant differences in acceptance and satisfaction with Restorative Justice processes between urban and rural populations. In urban areas, higher legal awareness and access to trained mediators contribute to a 70% satisfaction rate, reflecting better participation and understanding of the process. In contrast, rural areas exhibit a lower satisfaction rate of 50%, hindered by cultural norms, limited legal knowledge, and a shortage of qualified mediators. Despite these challenges, Restorative Justice shows promise in addressing domestic violence by fostering dialogue, accountability, and reconciliation, emphasizing victim empowerment and offender rehabilitation. This study underscores the necessity of adapting Restorative Justice practices to local socio-cultural contexts to enhance effectiveness. Recommendations include developing tailored mediator training programs, increasing public awareness, and integrating community leaders into the process to build trust and legitimacy. The research contributes to the discourse on legal reform by highlighting the potential of Restorative Justice to create a more inclusive, responsive, and sustainable mechanism for resolving domestic violence cases in Indonesia. These findings are pivotal for policymakers in designing adaptive strategies to bridge the urban-rural divide and strengthen the justice system.

Stability Analysis of DC Microgrids: Insights for Enhancing Renewable Energy Integration, Efficiency and Power Quality

In the current context of smart grids, microgrids have proven to be an effective solution to meet the energy needs of neighborhoods and collective buildings. This study investigates the voltage behavior and other critical parameters within a direct current (DC) microgrid to enhance system efficiency, stability, and reliability. The dynamic performance of a DC microgrid is analyzed under varying load and generation conditions, with particular emphasis on the voltage response and load-sharing mechanisms required to ensure stable operation. The findings indicate that specific control strategies, particularly droop methods, are effective in mitigating voltage fluctuations, enhancing power quality, and ensuring proper load distribution across multiple sources. This study also addresses significant challenges, including voltage regulation and fault resilience, to provide guidelines for designing robust and efficient DC microgrids. These insights are essential to inspire further advancements in control strategies and facilitate the practical deployment of DC microgrids as a sustainable solution for distributed energy systems, especially in scenarios prioritizing high DC load penetration and renewable energy integration.

The association between stent design and patient exercise intensity: structural coupling effects and hemodynamic analysis

IntroductionIn-stent restenosis remains a significant challenge in coronary artery interventions. This study aims to explore the relationship between exercise intensity and stent design, focusing on the coupled response of the stent structure and hemodynamics at different exercise intensities.MethodsA coupled balloon-stent-plaque-artery model and a fluid domain model reflecting structural deformation were developed to investigate the interaction between coronary stents and stenotic vessels, as well as their impact on hemodynamics. The study examines the influence of stent connectors on the mechanical response of both the plaque and the coronary artery, with hemodynamic analyses conducted under three exercise intensities: rest, moderate exertion, and maximal exertion.ResultsThe model effectively simulates the gradual expansion of the stent, plaque, and artery, as well as the recoil behavior post-expansion. The gradual adaptation of the stent to the plaque during the initial expansion phase helps mitigate the adverse effects of the dog-boning phenomenon. Areas of low time-averaged wall shear stress (TAWSS) and high relative residence time (RRT) are observed at both ends and near the stent, with a general decreasing trend as exercise intensity increases. Additionally, the study quantifies the changes in hemodynamic characteristics across different physiological states. Specifically, the areas of low TAWSS and high RRT are significantly reduced during moderate exertion, with no further substantial reduction observed at maximal exertion.DiscussionThese findings provide valuable insights for the design of stent connectors and offer guidance on optimal exercise intensity for patients undergoing stent interventions. Future research, combining dynamic vascular wall deformation and advanced imaging techniques, could lead to more precise and effective stent designs tailored to individual patients.

Numerical Modeling of Engineering-Scale Jointed Coal Mass and Confining Pressure Effect

In coal masses, joints serve as crucial components influencing mechanical responses and failure mechanisms. The joint distribution complicates the acquisition of physical parameters for engineering-scale coal masses, and traditional laboratory or in situ tests often suffer from inaccuracies and high costs. Therefore, examination of the dynamic properties of engineering-scale coal mass is generally performed by numerical simulations. This paper proposes a model construction approach using two-dimension Particle Flow Code (PFC2D) software to study the mechanical properties of engineering-scale jointed coal mass, addressing the limitations of conventional models by integrating scale effects, accuracy, and computational efficiency. Firstly, the distribution characteristics and mechanical parameters of the joints in the coal mass were obtained based on field statistics and laboratory experiments. The parameters of the laboratory-scale model were calibrated by the numerical matching method. The discrete element model for the engineering-scale coal mass was constructed by the step-by-step matching method. The confining pressure effect on the coal mass under a biaxial loading condition was studied, while the strength change, fissure evolution, and failure mechanism under different confining pressures and fissure degrees were investigated. Based on the simulation results, a quantitative relationship was established between the mechanical parameters, fissure degree, and confining pressure under compression conditions. Ultimately, the failure zone ahead of the working face and the distribution of the abutment pressure were assessed using the mechanics parameters of coal masses with diverse joint distributions.

Investigations on mechanical responses of frozen soil–rock mixture under cyclic loading: experiments and binary-medium-based multiscale constitutive model

Investigations on mechanical responses of frozen soil–rock mixture under cyclic loading: experiments and binary-medium-based multiscale constitutive model

Quantitative method and influencing factors analysis of demand response performance of air conditioning load with rebound effect

AbstractUnder the emerging trend of the new power systems, enhancing the energy flexibility of air conditioning loads to promote electricity demand response is crucial for regulating the real-time balance. As a typical temperature-controlled loads, air conditioning loads can generate rebound effect when participating in demand response, resulting in sudden load increases and posing risks to grid security. However, the existing research mainly focuses on the energy flexibility, which leads to an imperfect demand response mechanism and thus affects the optimal scheduling strategy. Therefore, the study proposes a comprehensive quantification method in view of rebound effect for the demand response performance of air conditioning loads, by using probability distribution, Latin hypercube sampling, Monte Carlo simulation, and scenario analysis methods. The demand response event was divided into response phase and recovery phase, and by considering energy flexibility during the response phase and rebound effect during the recovery phase, three dimensionless evaluation indexes for comprehensive demand response performance were constructed. Using this quantification method, the impact patterns of three types of random variables were compared, including meteorological, design variables, and control variables. Additionally, considering the differences in building types (office and hotel buildings) and building capacities (small, medium, and large), the effectiveness of air conditioning load participation in demand response measures in different building application scenarios was explored. The results show that the influence of the design variables on the response performance is less than that of the control variables, but significant, reaching 45% compared to the control variables. Moreover, the influence varies with building type, capacity and climate zone, and building demand response design has more potential in the following scenarios: the cold climate, the hot summer and cold winter climate, the medium building and the hotel building.

Response mechanism of major secondary metabolites of Polygonatum kingianum to selenium nanoparticles

Selenium nanoparticles (SeNPs) can be absorbed by plants, thereby affecting plant physiological activity, regulating gene expression, and altering metabolite content. However, the molecular mechanisms by which exogenous selenium affects Polygonatum kingianum coll.et Hemsl plant secondary metabolites remain unclear. In this study, we exposed P. kingianum plants to SeNPs at 0, 10, 25, and 50 mg/L concentrations. Joint physiological, metabolomic, and transcriptomic analyses were performed to reveal the response mechanisms of major secondary metabolites of P. kingianum to SeNPs. Our data shows that under the treatment of 25 mg/L, the photosynthetic electron transfer rate of plants significantly increases and the carbon-nitrogen ratio significantly decreases. In parallel, the main active components, polysaccharides and saponins, showed a significant increase in content, while flavonoid content decreased. SeNPs affect polysaccharide accumulation mainly through up-regulation of SPS, UGPase, AGPase, UTP, and SUS genes in starch and sucrose metabolic pathways. The accumulation of saponins was affected by upregulating genes in the sesquiterpenoid and triterpenoid biosynthesis pathways, including PAD, ADH, PK, and GS. The accumulation of flavonoids was mainly regulated by metabolic pathways such as flavonoid biosynthesis, isoflavonoid biosynthesis, and the biosynthesis of phenylpropanoids. In summary, this study reveals the key metabolic pathways affected by SeNPs in the main secondary metabolic products of P. kingianum.

Sulforaphane and Benzyl Isothiocyanate Suppress Cell Proliferation and Trigger Cell Cycle Arrest, Autophagy, and Apoptosis in Human AML Cell Line

Isothiocyanates (ITCs) are naturally occurring sulfur-containing compounds with diverse biological effects. This study investigated the effects of sulforaphane (SFN, an aliphatic ITC) and benzyl isothiocyanate (BITC, an aromatic ITC) on human acute myeloid leukemia SKM-1 cells, focusing on cell proliferation, cell death, and drug resistance. Both drug-sensitive SKM-1 cells and their drug-resistant SKM/VCR variant, which overexpresses the drug transporter P-glycoprotein, were used. SFN and BITC reduced cell viability in a dose-dependent manner, with BITC showing greater potency. IC50 values ranged from 7.0–8.0 µM for SFN and 4.0–5.0 µM for BITC in both cell types, with only slight differences between the variants. Both ITCs induced autophagy as evidenced by increased LC3-II production and caused a significant increase in the sub-G0/G1 cell population, especially with BITC. Apoptosis was more pronounced after BITC treatment, whereas SFN had a weaker effect. These results suggest that autophagy may act as a defense mechanism in response to ITC-induced apoptosis in human AML cells.

Mechanical Response and Failure Analysis of Stainless-Steel Beams Exposed to Elevated Temperatures

This research investigates the structural behaviour of stainless-steel beams (SSBs) when subjected to extreme temperatures, specifically in the context of fire-induced deformations. High temperatures, typical of fire occurrences, exert large thermal loads on SSBs, leading in material property changes that make the metal more brittle, stiffer, and brittle. The objective of this study is to investigate extensively the behaviour of SSBs under the combined impact of heat transfer and applied loads, with a focus on substantial deflections. To completely assess the performance of SSBs, we undertake parametric investigations and systematic research efforts. The initial phase comprises a thorough review of relevant data about the behaviour of SSBs at increased temperatures. Afterwards, a parametric study of the web section is conducted to determine the performance of the SSBs under exposure to fire and applied stresses. In order to ease the numerical research, the finite element (FE) program ABAQUS CAE is used to simulate stainless steel I-section beams of varying diameters subjected to realistic fire conditions according to the ISO 834 standard fire curve. The average discrepancy between numerical forecasts and experimental data for six separate models about the final temperature readings is 2.74 percent. Prior to actual collapse, the axial displacement of the SSBs decreases by around 7.5%, showing significant temperature influences on their strength. In addition, the axial deformation of the SSBs exhibits greater displacements in the web portion than in the flange section following fire exposure and loading. This discovery highlights the need to take into account the unique thermal expansion and stiffness characteristics of the web and flange components during fire occurrences. Utilising the finite element approach in ABAQUS reveals the resistance of SSBs to increased temperatures. The findings highlight the potential advantages of using stronger SSBs to maximise the structural response under fire conditions. This study gives useful insights into the thermal behaviour of SSBs and has important implications for building fire-resistant structures, boosting the fire safety of constructions, and enhancing their resistance against fire risks.

BODIPY‐Based Small‐Molecule Photoacoustic Probes for Biomedical Imaging

Advances in bioimaging technologies capable of visualizing physiological and pathological processes are of great significance for revealing diseases development and promoting clinical diagnosis and treatment. Photoacoustic (PA) imaging, utilizing small‐molecule probes, offers a promising approach for achieving high‐spatiotemporal‐imaging of dynamic biological process. The development of near‐infrared absorbing dyes has significantly contributed to the research of small‐molecule PA probes, particularly boron‐dipyrromethene derivatives (BODIPYs) known for their simple synthesis, tunable NIR photophysical properties and superior PA imaging abilities. This review highlights recent advances in biomedical applications of BODIPY‐based PA probes, including the design strategies, spectral characteristics, response mechanisms and applications for imaging biomarkers such as reactive oxygen/nitrogen species, gaseous signaling molecules and metal ions. The insights provided in this review are expected to guide future studies on small‐molecule PA probes for bioimaging and biosensing.

Quantitative analysis of septin Cdc10 & Cdc3-associated proteome during stress response in the fungal pathogen Cryptococcus neoformans.

Cryptococcus neoformans is a pathogenic basidiomycetous yeast that primarily infects immunocompromised individuals. Fatal outcome of cryptococcosis depends on the ability of C. neoformans to sense and adapt to 37°C. A complex of conserved filament forming GTPases, called septins, composed of Cdc3, Cdc10, Cdc11, and Cdc12, assembles at the mother-bud neck in C. neoformans. Septins Cdc3 and Cdc12 are essential for proliferation of C. neoformans at 37°C and for virulence in the Galleria mellonella model of infection, presumably due to their requirement for septin complex formation, and the involvement in cytokinesis. However, how exactly Cdc3, and Cdc12 contribute to C. neoformans growth at 37°C remains unknown. Based on studies investigating roles of septins in Saccharomyces cerevisiae, septin complex at the mother-bud neck of C. neoformans is predicted to interact with proteins involved in cell cycle control, morphogenesis, and cytokinesis, but the septin-associated proteome in C. neoformans has not been investigated. Here, we utilized tandem mass spectrometry to define C. neoformans proteins that associate with either Cdc3 or Cdc10 at ∼25°C or after the shift to 37°C. Our findings unveil a diverse array of septin-associated proteins, highlighting potential roles of septins in cell division, and stress response. Two proteins, identified as associated with both Cdc3 and Cdc10, the actin-binding protein profilin, which was detected at both temperatures, and ATP-binding multi-drug transporter Afr1, which was detected exclusively at 37°C, were further confirmed by co-immunoprecipitation. We also confirmed that association of Cdc3 with Afr1 was enhanced at 37°C. Upon shift to 37°C, septins Cdc3 and Cdc10 exhibited altered localization and Cdc3 partially co-localized with Afr1. In addition, we also investigated changes to levels of individual C. neoformans proteins upon shift from ∼25 to 37°C in exponentially grown culture and when cells entered stationary phase at ∼25°C. Our study reveals changes to C. neoformans proteome associated with heat and nutrient deprivation stresses and provides a landscape of septin-associated C. neoformans proteome, which will facilitate elucidating the biology of septins and mechanisms of stress response in this fungal pathogen.

Effects of Density and Temperature on the Mechanical Shock Mitigation Response of Polymethylene Diisocyanate (PMDI) Based Rigid Polyurethane Foams

Effects of Density and Temperature on the Mechanical Shock Mitigation Response of Polymethylene Diisocyanate (PMDI) Based Rigid Polyurethane Foams

Cantilever steel tubular pile wall embedded in soft rock subjected to sequential loadings

A centrifuge model is developed to simulate sequential dynamic and static loadings with clear boundary conditions, aiming to comprehend the mechanical response of a cantilever-type retaining wall embedded into the soft rock. The model wall was made of steel tubular piles with a 2 m diameter and 25 mm thickness in a prototype scale under 50g. Wall retained height (H) and embedment depth (dr) into model soft rock (qu = 1.4 MPa) were 12 and 3 m, respectively. Sequential loadings (dynamic and static) were applied to the wall with dry and saturated backfill sand. It was found that the resilience of the wall created by the confinement of soft rock during the dynamic loading is a critical factor that controls the earth pressure and the dynamic and residual displacements of the wall, both during and after the dynamic loading and the static loading. Due to the resilience effect, an effective earth pressure ratio of more than the design active or even an at-rest pressure coefficient could be expected, especially after dynamic loading. However, a slight wall movement in the static loading and wall creep displacement after dynamic loading could reduce this resilience effect.

Effects of polystyrene microplastics on the growth and metabolism of highland barley seedlings based on LC-MS

Microplastics are widely present in the environment and can adversely affect plants. In this paper, the effects of different concentrations of microplastics on physiological indices and metabolites of highland barley were investigated for the first time using a metabolomics approach, and revealed the response mechanism of barley seedlings to polystyrene microplastics (PS-MPs) was revealed. The results showed that the aboveground biomass of highland barley exposed to low (10 mg/L) and medium (50 mg/L) concentrations of PS-MPs increased by 32.2% and 48.2%, respectively. The root length also increased by 16.4% and 21.6%, respectively. However, the aboveground biomass of highland barley exposed to high (100 mg/L) concentrations of PS-MPs decreased by 34.8%, leaf length by 20.7%, and root length by 25.9%. Microplastic exposure increased the levels of antioxidant activity, suggesting that highland barley responds to microplastic stress through oxidative stress. Metabolome analysis revealed that the contents of 4 metabolites increased significantly with increasing PS-MPs concentration in positive ionmode, while the contents of 8 metabolites increased significantly with increasing PS-MPs concentration in negative ionmode (P < 0.05), including prunin, dactylorhin E, and schisantherin B. Additionally, PS-MPs significantly interfered with highland barley flavonoid biosynthesis, pyrimidine metabolism, purine metabolism, fatty acid biosynthesis, and phenylpropanoid biosynthesis metabolic pathways. This study provides a new theoretical basis for a deeper understanding of the effects of different concentrations of PS-MPs on highland barley.

Frequency response mechanism of surface smoothing and material removal on fused silica

Frequency response mechanism of surface smoothing and material removal on fused silica

Projected Changes of Kuroshio in a Warming Climate

Abstract The projected changes in the Kuroshio and the associated mechanisms in response to future warming scenarios remain unclear. While some studies propose a negative midlatitude wind stress curl (WSC) tendency could expedite Kuroshio recirculation, others suggest that the isopycnal transport of warmer subtropical mode water (STMW) to the east of the Kuroshio enhances only the velocity in the upper ocean. In the future projections under the shared socioeconomic pathways 5-8.5 (SSP5-8.5) within phase 6 of Coupled Model Intercomparison Project (CMIP6) model ensemble, a consistent enhancement of the Kuroshio along the Japanese coast (JP-Kuroshio) is observed. Particularly, the response of the JP-Kuroshio to WSC changes is more pronounced in high-resolution (HR) models than low-resolution (LR) ones. However, diverse results emerge in the East China Sea (ECS-Kuroshio). While most CMIP6 HR models indicate a reduction of Kuroshio within the upper 1000 m in the ECS-Kuroshio, the ensemble of CMIP6 LR models shows an intensification of Kuroshio within the upper 300 m and a deceleration below, suggesting a consistent baroclinic feature in ECS-Kuroshio. Additional ocean model sensitivity experiments confirm that the WSC influences the Kuroshio throughout the entire water column, particularly below 300 m. Within the upper 300 m, the primary driver of Kuroshio changes is the surface warming, aligning with the STMW mechanism. Moreover, the surface salinity flux may also play an important role in the dynamics of Kuroshio changes.