Behavior Of Mechanism Research Articles

Behavior modeling for a new flexure-based mechanism by Hunger Game Search and physics-guided artificial neural network

Compliant mechanism has some advantages and has been widely applied in many accurate positioning systems. However, modeling the compliant mechanism behavior has suffered from many challenges, such as unstable results, and the limitation of training data set. In the field of compliant mechanism modeling, there has been no research interested in applying meta-heuristics optimization algorithms to optimize the weights and biases of the neural network globally. Additionally, the Physics-Guided Artificial Neural Network, a research direction that has received much attention recently, has not been considered in problems related to compliant mechanisms. In order to surmount those drawbacks, this paper pioneers a new approach to model behaviors of a compliant mechanism using the Hunger Game Search and the Physics-Guided Artificial Neural Network. The Hunger Game Search can directly search the model’s weights and biases so that the target function that takes advantages of both physical and data information can be minimized. The investigations on diverse training set ratios and the ANOVA tests at the significance level reveal that using the Hunger Game Search can result in smaller errors than using the backpropagation method. Furthermore, applying the Hunger Game Search to a Physics-Guided Artificial Neural Network not only can reduce error but also can increase convergence speed compared to applying Hunger Game Search to conventional neural networks. Those results demonstrate the potential of the proposed method in modeling the behavior of compliant mechanisms.

Analysis of an unsteady mucus flow through an isothermal channel with thermal conduction: An analytical solution

The human body regularly produces mucus, and its presence does not mean that something bad is going on. The boundary tissues of mammals, including the nose, throat and lungs, serve as a barrier against pollution and are produced by our respiratory system. Our work describes the flow comprehension of the components moulding the fluid elements of respiratory irresistible infections. A mathematical model is introduced to concentrate on the mucus fluid flow driven by natural convection through asymmetric channel. This study also summarized biological disorder of human lung build-up fluid. The nonlinear governing equations contain importance of heat transfer and fluid motion of mucus fluid. The analytic solutions of unsteady mucus flow through an isothermal channel with thermal conduction are accomplished adopting Laplace transform method. Significance of mucus fluid heat source thermal conductivity on momentum distribution and energy distribution is enumerated. The comparison of various dimensionless parameters is shown graphically with the help of MATLAB software. In order to provide some understanding on the behavior of mucus fluids and heat transfer mechanisms, extension of this study explores at how temperature influences mucus flow properties.

Behavior and Mechanisms of Antimony Precipitation from Wastewater by Sulfate-Reducing Bacteria Desulfovibrio desulfuricans

The development of the non-ferrous metal industry is generating increasingly large quantities of wastewater containing heavy metals (e.g., Sb). The precipitation of heavy metals by microorganisms involves complex mechanisms that require further investigation to optimize bioremediation technologies. In this study, we employed a sulfate-reducing bacteria (SRB) strain Desulfovibrio desulfuricans CSU_dl to treat the antimony (Sb)-containing wastewater; the behavior of Sb and mechanisms underlying precipitation were investigated by characterizing the precipitates. The results showed that the abiotic factors constraining SRB bacterial growth greatly affect Sb forms and precipitation. For instance, Sb precipitation maximumly occurred at pH 6 and 7, or C:N ratio of 10:1 and 40:3 for Sb(III) and Sb(V), respectively, resulting in a maximum Sb removal rate of 94%. Interestingly, we found that substantial antimonate and antimonite were adsorbed on the SRB cell surface, indicating that cell surface is a critical reaction site of Sb transformation and precipitation. Sb was adsorbed to the cell surface by C-C and C=O groups, and was further precipitated by forming Sb2S3 and Sb2S5 or was coprecipitated with the P-containing group. Partial Sb(V) reduction was also observed on the SRB cell surface. These results provided a deep insight into the Sb bio-transformation and were an advancement with respect to understanding bioremediation of Sb-contaminated wastewater.

Effects of the Interaction of Salinity and Rare Earth Elements on the Health of Mytilus galloprovincialis: The Case of Praseodymium and Europium.

The growing use of products containing rare earth elements (REEs) may lead to higher environmental emissions of these elements, which can potentially enter aquatic systems. Praseodymium (Pr) and europium (Eu) are widely used REEs with various applications. However, their ecotoxicological impacts remain largely unexplored, with poorly understood risks to wildlife. Moreover, organisms also face environmental stressors like salinity fluctuations, and the nature of the interaction between salinity variations and contaminants is not yet clear. Therefore, this study aimed to evaluate the influence of salinity shifts on the impacts of Pr and Eu on adult mussels and the sperm of the species Mytilus galloprovincialis after 28 days and 30 min of exposure, respectively. To do so, biochemical and histopathological alterations were evaluated in adults, while biochemical and physiological changes were analysed in sperm. Additionally, the Integrated Biological Index (IBR) was calculated to understand the overall impact of each treatment. The results showed that adult mussels were most affected when exposed to the combination of high salinity and each element, which altered the behaviour of defence mechanisms causing redox imbalance and cellular damage. On the other hand, sperm demonstrated sensitivity to specific REE-salinity combinations, particularly Pr at lower salinity and Eu at higher salinity. These specific treatments elicited changes in sperm motility and velocity: Pr 20 led to a higher production of O2- and a decrease in velocity, while Eu 40 resulted in reduced motility and an increase in irregular movement. At both lower and higher salinity levels, exposure to Eu caused similar sensitivities in adults and sperm, reflected by comparable IBR scores. In contrast, Pr exposure induced greater alterations in sperm than in adult mussels at lower salinity, whereas the reverse was observed at higher salinity. These findings suggest that reproductive success and population dynamics could be modulated by interactions between salinity levels and REE pollution, highlighting the need for further investigation into how REEs and environmental factors interact. This study offers valuable insights to inform policymakers about the potential risks of REE contamination, emphasising the importance of implementing environmental regulations and developing strategies to mitigate the impact of these pollutants.

Monetary Policy and the Stock Market: Analysis and Proposals

The evolution of monetary policy in recent years can probably be explained by the different characteristics of the behavior of monetary policy transmission mechanisms in relation to changes in the structure of financial systems. These changes are related to developments in the international financial and economic environment. In particular, the development and liberalization of financial markets, the deregulation of the financial system and the emergence of financial innovations. Our literature review aims to identify the main findings of rigorous studies on the link between the stock market and monetary policy. In this article, we extend this intuition by trying to understand the mechanisms through which monetary policy influences stock market prices.

Shear Behaviour of the Post-tensioned Segmental Precast Concrete Pontoon Deck with the GFRP Rods

The present experimental and numerical study evaluated the structural performance of segmental concrete pontoon decks reinforced and post-tensioned with GFRP rods. Four large-scale decks were tested and the load-displacement response, strain behaviour of rods, concrete, and failure mechanism in four different prestressing levels were assessed. It was found that a small post-tensioning of 7.4% of the rod's ultimate tensile strength reduced the self-weight deflection by 92% and increased initial stiffness by 8.7 times compared to segmental decks without prestressing. Failure in prestressing decks typically began with concrete crushing at the joint with an increased compression depth due to increased initial post-tension; however, the ultimate failure mechanism of the hand-tight deck was governed by the interlaminar shear of the rod. A finite element model was developed and verified against test results A parametric study evaluating the influence of the post-tensioning at higher load, rod depth, concrete properties, rod number, and deck geometry was implemented. It was shown that increasing the post-tension load and depth of the rod improved the stiffness and reducing the spacing can result in a more uniform compression stress in the joint. This study provides design recommendations for ACI 440.4 R-04, by considering the concrete compression depth between joints rather than the depth of the FRP rod and contributes to a more accurate load estimation of the concrete crushing caused by joint openings. The results of this research could rectify the present problems with the construction design of maritime infrastructure and offer an innovative solution.

Enhanced Unmanned Surface Vehicle Path Planning Based on the Pair Barracuda Swarm Optimization Algorithm: Implementation and Performance in Thousand Island Lake

The path planning problem for unmanned surface vehicles (USVs) is related to multiobjective optimization, including shortest path, minimum energy consumption, and obstacle avoidance, making it particularly complex in multi-island and multiobstacle environments such as Thousand Island Lake. An enhanced path planning method for USVs based on the pair barracuda swarm optimization (PBSO) algorithm is proposed, and the complex water environment of Thousand Island Lake is taken as an example. The PBSO algorithm simulates the social behaviour of pair barracuda innovative and deep memory mechanisms, which can enhance the algorithm’s global search ability and local optimal escape ability in high-dimensional space. The probabilistic roadmap (PRM) method was initially used to model complex environments with multiple islands and obstacles. Moreover, four evaluation indicators were proposed to evaluate the performance of the obtained path: total navigation distance (TND), number of returns (NT), average turning angle (ATA), and minimum safe distance (MSD) from obstacles. The PBSO algorithm is used to optimize the initial path to reduce frequent turns and turning amplitudes during navigation. Path planning experiments were conducted on four simulated map environments with different ranges and complexities. Compared with state-of-the-art heuristic path planning methods, our method can identify the optimal path faster and has better stability. The enhanced USV path planning method based on the PBSO algorithm provides a new path planning strategy for the practical application of USVs under the real Thousand Island Lake.

Wavelength-specific inactivation mechanisms and efficacies of germicidal UVC for airborne human coronavirus

Ultraviolet germicidal irradiation (UVGI) technology can inhibit the environmental transmission of airborne pathogens, but the dose-response behavior of airborne human coronavirus and wavelength-specific inactivation mechanisms are not well understood. This study investigated three competitive UVC sources for their inactivation efficacy and mechanisms against human coronavirus OC43 (HCoV-OC43). Results showed the following order of inactivation efficacy: 222-nm KrCl excimer lamp > 263-nm UV-LEDs > 254-nm low-pressure mercury lamp. The 222-nm KrCl excimer lamp achieved a 5-log inactivation of aerosolized HCoV-OC43 with a dose of less than 1 mJ/cm², while the 263-nm UV-LEDs had the highest genome damage rate constant at 7.08 ± 0.85 mJ/cm². Although 222-nm Far-UVC caused less genome damage, it affected viral proteins more significantly, specifically the nucleocapsid (N) and spike (S) proteins, which lead to compromising capsid integrity and binding ability to host cells. Capsid integrity RT-qPCR and binding assay RT-qPCR used in this study could better monitor infectivity of airborne coronavirus than standard RT-qPCR. Additionally, significant lipid oxidation of HCoV-OC43 was observed under 222-nm irradiation, potentially impacting overall inactivation efficacy. This study provides detailed evidence on the effects of different UVC wavelengths on airborne HCoV-OC43, contributing to the optimization of UVC irradiation for indoor bioaerosol disinfection.

Reaction-controlled triple O-isotope exchange trajectories during experimental alteration of olivine

The measurements and application of triple O-isotope system is a relatively new and powerful tool in tracing water-rock interaction, allowing to distinguish the temperature-dependent fractionation from the water amount that interacted with the rock. While the use of 18O/16O fractionation between minerals and fluids is well-established, most natural mineral-water reactions remain uncharacterized in terms of the triple isotope fractionation (17O/16O and18O/16O). The triple O-isotope approach is especially promising when it comes to natural samples, where an array of exchanged samples constrains the fluid endmembers. However, multiple exchange mechanisms are likely to occur between the reacting rock and water, which has not been investigated for triple O-isotopes. This study examines the triple O-isotope exchange between fluid and olivine experimentally, as this is a common reaction in nature and mechanisms/rates of reaction are societally important for CO2 sequestration. Water-olivine reaction in batch experiments was investigated at 275 °C at the saturated water vapor pressure of 59.5 bar. Reactants were loaded at mass ratios 0.6 to 2 and exchanged for periods of time between 44 and 1048 h. Local meteoric water and mantle olivine were taken as the initial reactants. The mineral products are brucite, serpentine and minor magnetite that occur as coatings on unreacted olivine as well as individual crystals. The progress of this dissolution-precipitation reaction was traced with the δD-δ′18O-Δ′17O values of reacted fluids and mineral products. After 1048 h of reaction, ∼50 wt% of unreacted olivine remained. In general, experimental data conforms with the triple O-isotope fractionation factors calculated for the co-existing secondary minerals forming in equilibrium with fluid. However, there is scatter and deviations in the reacted fluid compositions likely driven by the difference in relative rates of secondary mineral formation and changing modal and chemical mineral composition. We observe that brucite and magnetite form abundant aggregates early in the progress of the reaction, while chrysotile forms fine-grained coatings that become abundant later. Since individual mineral-water fractionation 103ln18/16α range over 10 ‰ with θ ranging between 0.51 and 0.53, the dynamic behavior of dissolution-precipitation mechanism during alteration of olivine is the main factor to the “wandering” triple O-isotope trajectories in our relatively short experiments.

Computational Studies of Molybdenum-Containing Metal–Sulfur and Metal–Hydride Clusters

The development of transition metal clusters is an active area of research in inorganic chemistry, as they can be used as catalysts to perform chemically or biologically relevant reactions. Computational chemistry, employing density functional theory (DFT), plays a key role in rationalizing the electronic structure and properties of transition metal clusters. This article reviews recent quantum chemical studies of Mo3S4M clusters (M = Fe, Co, Ni), their CO- or N2-bound variants, and metal–hydride clusters. The ground state of the cluster systems was computed, and properties such as metal–metal bonding, orbital interactions, fluxional behavior of ligands, spectroscopy, and reaction mechanisms were rationalized and compared with available experimental results. Our research findings evidence that computational studies employing quantum chemical methods can guide experimental researchers to develop novel transition metal clusters for potential applications in catalysis.

Pressure distributions and flow regimes: An integrated approach for CO2 sequestration project design and evaluation in hydraulically fractured shale reservoirs

This paper introduces an integrated approach for estimating the key parameters of CO2 storage projects in depleted hydraulically fractured shale reservoirs. The approach focuses deep insights into evaluating these projects based on the pressure distribution and flow regimes. The objective is reducing the uncertainties in the design and evaluation criteria of CO2 storage by better understanding the flow mechanisms in the porous media. This understanding helps in perfectly modeling CO2 distribution and characterizing the expected flow regimes.Several analytical models are developed for the pressure behavior of CO2 multi-size scale flow mechanisms. Diffusion flow, slip flow, adsorption flow, and Darcy and non-Darcy flow are all considered. The flow in the nano-size organic particles, the micro-size kerogen particles, and the macro-size matrix is analytically described. The flow inside natural fractures in the stimulated and unstimulated reservoir volume as well as the flow of CO2 in the hydraulic fractures are modeled. Several rectangular reservoir configurations, hydraulic fracture characteristics, and petrophysical properties of the matrix, kerogen, and organic matter are examined. An estimation model for the total volume of CO2 that could be stored in the depleted fractured reservoirs is presented. The contribution of the unstimulated and stimulated porous media as well as the hydraulic fractures to the total volume is determined by characterizing the flow regimes. Different models are proposed for the time at which CO2 reaches the hydraulic fracture tips, the borders between stimulated and unstimulated porous media, and the reservoir boundary. Profound explanations are introduced for the impact of the constrained pressure on the total capacity of the reservoirs for CO2 storage.The study has reached several conclusions. The characteristics of the organic matter, kerogen, and the micro-size scale matrix do not significantly impact the pressure distribution and flow regimes. Conversely, the pressure distribution and flow regimes are significantly impacted by the characteristics of the hydraulic and natural fractures. The hydraulic fractures may offer a reasonable capacity for CO2 storage, meanwhile, the capacity of stimulated and unstimulated reservoir volume is controlled by reservoir configuration and fracture spacing. The constrained pressure may strictly reduce the total capacity of CO2 storage in the reservoir. The total volume of the injected CO2 can be determined from the pressure point when the injection pulse has reached to reservoir boundary. Beyond this point, it is not recommended to inject CO2 as it could increase reservoir pressure more than initial pressure. The pressure of the depleted reservoir before injection is a key parameter in the design and evaluation of the CO2 storage in shale reservoirs.This study introduces a novel approach for the design and evaluation criteria of CO2 storage in depleted shale reservoirs. The approach uses the pressure distribution and flow regimes that could be observed in the multi-size scale components of the reservoirs. The study proposes several models for estimating CO2 geosequestration capacity in the hydraulic fractures, stimulated and unstimulated reservoir volume as well as the total storage capacity of the reservoirs. The approach confidently addresses the concerns regarding the applicability of unconventional resources for CO2 storage and the total capacity offered by these reservoirs for this purpose.

Deep Learning-Driven Analysis of a Six-Bar Mechanism for Personalized Gait Rehabilitation

Abstract Recent advances in robotics and artificial intelligence have highlighted the potential for the integration of computational intelligence in enhancing the functionality and adaptability of robotic systems, particularly in rehabilitation. Designing robotic exoskeletons for the lower limb rehabilitation of post-stroke patients requires frequent adjustments to accommodate individual differences in leg anatomy. This complex engineering challenge necessitates a deep understanding of human physiology, robotics, and optimization to develop adaptive robotic systems and also to swiftly quantify the required adjustments and implement them for each patient. The conventional approaches, which mostly rely on heuristics and manual tuning, often struggle to achieve optimal results. This paper presents a novel method that integrates a genetic algorithm with a deep learning approach to generate a gait trajectory of the ankle joint from a six-bar linkage mechanism of fixed dimensions. Later, using the same approach, the inverse kinematics solution for this mechanism is also devised whereby, the set of the link dimensions of the six-bar linkage mechanism is obtained for the given gait trajectory of an individual to achieve customization. We simulated the kinematic behavior of the six-bar linkage mechanism within defined mechanical constraints and utilized the generated data for training a feedforward neural network and long short-term memory models. The proposed model, when trained, can produce accurate lengths for the desired gait trajectories in the sagittal plane and vice versa, which further validates our proposed approach for inverse kinematics solution. Moreover, to evaluate the efficiency of deep learning models, we have conducted an extensive error-based, comparative, and sensitivity analysis using different performance indices. The results highlight the potential of the proposed deep-learning-driven approach in the design analysis of gait rehabilitation robots.

Investigation of Tensile Properties and In Situ Analysis of Fracture Behavior in High-Porosity Open-Cell Nickel Foam.

Nickel foam offers excellent conductivity, a high surface area, and lightweight structure, making it ideal for applications, like battery electrodes, catalysts, and filtration systems. Its durability and corrosion resistance further enhance its performance in various industries. However, few studies focus on the tensile anisotropy of nickel foam and its tensile fracture process. In this study, the anisotropic tensile behavior of nickel foam with varying relative densities has been investigated, along with its tensile fracture behavior using in situ techniques. The tensile properties of nickel foams show strong anisotropy due to the flattening process in the production process. The results show that the tensile properties, including the yield strength, tensile strength, and elastic modulus, increase with the increasing relative density, while the elongation percentage has no relationship with the relative density. The experiment data on tensile strength are in agreement with Gibson's formula and Liu's formula. In situ tensile tests are conducted to explore the microscopic fracture mechanism of nickel foam. The results show that the struts of nickel foam are tensile fractures or shear fractures near the joints, and the fracture process of struts is clearly recorded and analyzed. This study is significant as it provides critical insights into the anisotropic tensile behavior of nickel foam and fracture mechanism, enabling the optimization of production processes and broadening its potential applications.

Interaction of microstructure evolution mechanism in Ti-0.3Mo-0.8Ni alloy with initial lamellar microstructure during isothermal compression below the β-transus

The flow behavior and interaction of microstructure evolution mechanisms for a near α Ti-0.3Mo-0.8Ni alloy with as-cast lamellar microstructure are investigated at temperatures of 800∼880 °C in the α+β region with wide strain rate range from 0.01s−1 to 30s−1 during isothermal compression. It is demonstrated that the main reasons of flow softening in the true stress-true strain curves are the kinking of lamellar α, dynamic α→β transformation (DT), dynamic spheroidization (DS), and dynamic recovery (DRV) of β grain. The instability phenomena such as adiabatic shear band (ASB) and flow localization (FL) are the main causes of the stress collapse in the curves at higher strain rate. The dislocation density at the kinking position of initial lamellar α is higher. With the increase of strain rate, the mechanism of the DS changes from flat separation to slat shear. The diffusion of the β-stabilizer results in starting the DT, promoted by the thermodynamic coupling. The interactions between different microstructure evolution mechanisms are extremely complex. In the early stage of hot deformation, the DT promotes the kinking of lamellar α. With the increase of deformation amount, the DT inhibits the DS at higher strain rates, and conversely, the DS promotes the DT. At lower strain rates, the DT and DS accelerate each other in the middle and late stages of hot deformation. The DT and DS are restricted by the process of lamellar α kinking in the middle and late stages of hot deformation.

Multispacecraft Observations of Protons and Helium Nuclei in Some Solar Energetic Particle Events toward the Maximum of Cycle 25

The intricate behavior of particle acceleration and transport mechanisms complicates the overall efforts in formulating a comprehensive understanding of solar energetic particle (SEP) events; these efforts include observations of low-energy particles (from tens of keV to hundreds of MeV) by space-borne instruments and measurements by the ground-based neutron monitors of the secondary particles generated in the Earth atmosphere by SEPs in the GeV range. Numerous space-borne missions provided good data on the nature/characteristics of these solar particles in past solar cycles, but more recently—concurrently with the rise toward the maximum of solar cycle 25—the High-Energy Particle Detector (HEPD-01) proved to be well suited for the study of solar physics and space weather. Its nominal 30–300 MeV energy range for protons can enlarge the detection capabilities of solar particles at low Earth orbit, closer to the injection limit of many SEP events. In this work, we characterize three SEP events within the first six months of 2022 through spectral and velocity dispersion analysis, assessing the response of HEPD-01 to >M1 events.

A novel bi-level decision-making approach based on game theory for mechanism design

This study addresses the bi-level multi-objective optimization problems raised in reliability-based robust design optimization (RBRDO) of engineering applications through establishing a state-of-the-art game theoretic scenario. A novel bi-level decentralized decision-making approach is proposed using the synergy of RBRDO, game theory, Monte Carlo simulation (MCS), and genetic programming (GP). The application of the proposed approach is elaborated in a case study of robust synthesis of high-speed path-generating four-bar mechanisms. The four performance criteria, namely, accuracy ( TE), robustness ([Formula: see text] TE and [Formula: see text]2 TE), reliability ( f G) at the upper level, and quality of motion ( TA) at the lower level are assigned to four players so that each of whom is in charge of one objective criterion. The peak input driving torque ( T S) is associated with the upper-level problem. The GP meta-model is used to capture the Stackelberg protocol that is, constructing the follower’s rational reaction set (RRS) and the Nash bargaining function is hired to model the cooperative behavior. The obtained results show a considerable enhancement in reliability and robust behavior of mechanism, while the deterministic criteria of accuracy and quality of motion are preserved.

Synergistic interaction behavior of deformation mechanisms in a new metastable β-Ti alloy with high strain hardening rate

The present study successfully designed a novel metastable β titanium alloy, Ti–8.8Cr–1.9Sn, exhibiting exceptionally high strain-hardening rate (∼2.4 GPa) as well as significant total elongation (∼48.2 %). Detailed analysis of the microstructure revealed that the successive activation of primary mechanical twins and primary SIM α" within β phases, along with secondary mechanical twins and secondary SIM α" within twinning zones during deformation, which results in a highly intricate network of deformation microstructures. Meanwhile, during deformation the microstructure undergoes dynamic refinement through the continuous occurrence of mechanical twinning and phase transformations, leading to a reduction in dislocation mean free path, thereby enhancing the strain-hardening rate. Importantly, the microstructural heterogeneity is formed due to generation of numerous heterogeneous interfaces, including β/α'', β/twin, α''/twin as well as twin/twinnano, thereby inducing additional HDI hardening resulting from the formation of GNDs for accommodating strain gradients near these interfaces. Furthermore, the relative mobile dislocation density ρm/ρm0 is significantly high during deformation, due to a reduced exhaustion rate and a high nucleation rate of mobile dislocations. The values of activation volume Va and V∗ typically range from 1b3–100b3, indicating the occurrence of cross-slip and dislocation nucleation. The interaction and accumulation between GNDs and mobile dislocations further contribute to the improvement of strain hardening rate. Therefore, the synergistic interaction activities of multiple deformation mechanisms lead to enhanced strain-hardening rate along with the large plasticity.

Flap and Wing Dynamics for a Light Sport Aircraft Analysis Using a Topological Model

This paper presents a more general method to study the dynamic behavior of a planar mechanism with joints. To do this, Graph Theory is used. A topological description is presented based on which a corresponding graph is attached to any mechanism. This method can be used for both kinematic and dynamic study in the same model, and many of the descriptors used in kinematic analysis can also be used for dynamic analysis. As a final result, the motion equations of the studied mechanical system can be obtained. An application is made to a flap and wing control system of a light sport aircraft. The graph associated with the mechanism first used to determine the field of velocities and accelerations of the mechanism elements is then used to obtain the motion equation for the control system. In this way, Graph Theory proves useful for the parallel study of both the kinematic and dynamic study of such problems.

Global research trends and hotspots in overweight/obese comorbid with depression among children and adolescents: A bibliometric analysis.

Overweight/obesity combined with depression among children and adolescents (ODCA) is a global concern. The bidirectional relationship between depression and overweight/obesity often leads to their comorbidity. Childhood and adolescence represent critical periods for physical and psychological development, during which the comorbidity of overweight/obesity and depression may increase the risk of adverse health outcomes. To evaluate the relationship between ODCA, we conduct a bibliometric analysis to aid in formulating prevention and treatment strategies. From 2004 to 2023, articles related to ODCA were selected using the Science Citation Index Expanded from the Web of Science Core Collection. Bibliometric analysis of relevant publications, including countries/regions, institutions, authors, journals, references, and keywords, was conducted using the online bibliometric analysis platforms, CiteSpace, VOSviewer, and bibliometrix. Between 2004 and 2023, a total of 1573 articles were published on ODCA. The United States has made leading contributions in this field, with Harvard University emerging as the leading contributor in terms of research output, and Tanofsky being the most prolific author. The J Adolescent Health has shown significant activity in this domain. Based on the results of the keyword and reference analyses, inequality, adverse childhood experiences, and comorbidities have become hot topics in ODCA. Moreover, the impact of balanced-related behavior and exploration of the biological mechanisms, including the potential role of key adipocytokines and lipokines, as well as inflammation in ODCA, have emerged as frontier topics. The trend of a significant increase in ODCA publications is expected to continue. The research findings will contribute to elucidating the pathogenic mechanisms of ODCA and its prevention and treatment.

The hydrogen-helium-vacancy interaction and hydrogen-vacancy clusters formation mechanisms in chromium: A first-principles study

Attributing to excellent corrosion resistance and low neutron absorption cross-section, chromium (Cr) has been considered as a promising advanced structural nuclear material. Under extreme radiation conditions, the coexistence of vacancies (Vac), hydrogen (H), and helium (He) modifies the evolution trajectory of H-defect clusters, and significantly impacts the performance of materials, all of which are under extensive investigations. Here, the occupancy mechanism of H atoms and influencing factors in Vac1/He1Vac1 systems are comprehensively studied by first-principles calculations. Based on the exhaustive investigation of H-He-Vac interactions, the equilibrium distance between H-H pairs is delineated. Serving as an effective trap center, the Vac1/He1Vac1 cluster exhibits robust attractive forces capable of luring dissociative H atoms within the crystal lattice. The accumulation of H atoms from remote regions towards the defects results in the formation of stable Hn-Vac1/Hn-He1Vac1 complexes. Moreover, it is revealed that the hydrogen-enhanced vacancy mechanism and meticulously examines the factors affecting defect-trapping capabilities and the growth of H-He-Vac complexes, providing an insight into the behavior of hydrogen-defects clusters formation mechanism and the H-He-Vac interaction in Cr.