Search Results (323)

The totem-pole bridgeless power factor correction (PFC) circuit based on the triangular current mode (TCM) in the front-end PFC of a switching power supply has the advantage of realizing zero-voltage switching (ZVS) in the full working range. However, the TCM control based on the critical conduction mode (CRM) further increases the inductance current ripple, and the traditional input voltage AC sampling circuit increases the circuit complexity and device cost. Therefore, this paper studies the corresponding improvement technology from two dimensions. Firstly, the coordinated interleaved parallel technology is employed to design the system’s overall control-improvement strategy. This approach not only achieves full working-range ZVS but also reduces both the inductor current ripple and power device stress. Simultaneously, an optimized input voltage sampling circuit is designed to accommodate varying voltage requirements of control chip pins. This circuit demonstrates strong synchronization in both voltage and phase sampling, and the structural characteristics of the optocoupler can also suppress electrical signal interference. Finally, a 600 W totem-pole bridgeless PFC prototype is developed. The experimental results demonstrate the effectiveness of the proposed improved method. The prototype efficiency peak reaches 97.3%. Full article

Providing long-term care for a person with Alzheimer’s disease is associated with chronic stress and emotional overload. One of the key predictors of emotional burden is the amount of time devoted to caregiving, which intensifies the experienced stress. Additional risk factors include the stage of the illness, difficulties in the care recipient’s activities of daily living, the caregiver’s neglect of their own needs, and challenging behaviours exhibited by the person receiving care. Therefore, it is essential to identify the psychological protective resources of caregivers that can buffer the impact of stress. Background/Objectives: The objective of the study was to explore the psychological mechanisms underlying the involvement of caregivers supporting individuals with Alzheimer’s disease. A moderated mediation model was employed, in which stress indirectly affects caregiver involvement through a sense of coherence, and the strength of this relationship is moderated by the amount of time devoted to caregiving. Methods: The bootstrapping method was applied using 5000 resamples within a 95% bias-corrected confidence interval. The analysis accounted for variables such as stress levels, sense of coherence, involvement in caregiving, duration of care, education, gender, age, and stage of the illness. Results: The sense of coherence mediated the relationship between stress and involvement in caring (B = 0.0063, SE = 0.0031, 95% CI [0.0012, 0.0135]), and this indirect effect was contingent upon the amount of time devoted to helping. The relationship between sense of coherence and involvement in caring was significant at the mean level (B = 0.005, SE = 0.002, 95% CI [0.0004, 0.0101]) and became stronger at high levels of time devoted to caring (+1 SD; B = 0.009, SE = 0.003, 95% CI [0.0030, 0.0148]). These results indicate that the positive association between sense of coherence and caregiver involvement increases with the amount of time spent caring. Conclusions: The results highlight the importance of strengthening caregivers’ resilience resources—such as a sense of coherence—in preventing overload. The model may serve as a foundation for developing interventions aimed at supporting caregivers’ mental health. Full article

The current study demonstrates the buckling properties of composite laminates reinforced with MWCNT fillers using a novel higher-order shear and normal deformation theory (HSNDT), which considers the effect of thickness in its mathematical formulation. The hybrid HSNDT combines polynomial and hyperbolic functions that ensure the parabolic shear stress profile and zero shear stress boundary condition at the upper and lower surface of the plate, hence removing the need for a shear correction factor. The plate is made up of carbon fiber bounded together with polymer resin matrix reinforced with MWCNT fibers. The mechanical properties are homogenized by a Halpin–Tsai scheme. The MATLAB R2019a code was developed in-house for a finite element model using C⁰ continuity nine-node Lagrangian isoparametric shape functions. The geometric nonlinear and linear stiffness matrices are derived using the principle of virtual work. The solution of the eigenvalue problem enables estimation of the critical buckling loads. A convergence study was carried out and model efficiency was corroborated with the existing literature. The model contains only seven degrees of freedom, which significantly reduces computation time, facilitating the comprehensive parametric studies for the buckling stability of the plate. Full article

This paper addresses the errors that arise when calculating the convective heat transfer in concentric annular pipes by using the equivalent diameter and turbulent heat transfer formula for circular pipes. This approach employs numerical simulations to solve the Reynolds-averaged Navier–Stokes equations and uses the realizable k–ε turbulence model and a low Reynolds number model near a wall. This study conducts numerical simulations of turbulent convective heat transfer within a concentric annular pipe. The results show that the shear stress on the inner wall surface of the concentric annular pipe and the heat transfer Nusselt number are significantly higher than those on the outer wall surface. At the same Reynolds number, both the entrance length and the peak velocity increase upon increasing the inner-to-outer diameter ratio. A correction factor for the inner-to-outer diameter ratio is proposed to achieve differentiated and accurate predictions for the inner and outer wall surfaces. The results clearly demonstrate the effect of the inner-to-outer diameter ratio on heat transfer. Full article

Erythropoiesis, the process driving the differentiation of hematopoietic stem and progenitor cells to mature erythrocytes, unfolds through tightly orchestrated developmental stages, each defined by profound epigenetic remodeling. From the initial commitment of hematopoietic progenitors to the terminal enucleation of erythrocytes, dynamic changes in chromatin accessibility, transcription factor occupancy, and three-dimensional genome architecture govern lineage specification and stage-specific gene expression. Advances in our understanding of the regulatory genome have uncovered how non-coding elements, including enhancers, silencers, and insulators, shape the transcriptional landscape of erythroid cells. These elements work in concert with lineage-determining transcription factors to establish and maintain erythroid identity. Disruption of these epigenetic programs—whether by inherited mutations, somatic alterations, or environmental stress—can lead to a wide range of hematologic disorders. Importantly, this growing knowledge base has opened new therapeutic avenues, enabling the development of precision tools that target regulatory circuits to correct gene expression. These include epigenetic drugs, enhancer-targeted genome editing, and lineage-restricted gene therapies that leverage endogenous regulatory logic. As our understanding of erythroid epigenomics deepens, so too does our ability to design rational, cell-type-specific interventions for red blood cell disorders. Full article

Dewatering and excavation are fundamental processes influencing soil deformation in deep foundation pit construction. Excavation causes stress redistribution through unloading, while dewatering lowers the groundwater level, increases effective stress, and generates seepage forces and compressive deformation in the surrounding soil. To systematically investigate their combined influence, this study conducted a scaled physical model test under staged excavation and dewatering conditions within a layered multi-aquifer–aquitard system. Throughout the experiment, soil settlement, groundwater head, and pore water pressure were continuously monitored. Two dimensionless parameters were introduced to quantify the contributions of dewatering and excavation: the total dewatering settlement rate ${\eta }_{dw}$ and the cyclic dewatering settlement rate ${\eta }_{dw,i}$. Under different experimental conditions, ${\eta }_{dw}$ ranges from 0.35 to 0.63, while ${\eta }_{dw,i}$ varies between 0.32 and 0.82. Both settlement rates decrease with increasing diaphragm wall insertion depth and increase with greater dewatering depth inside the pit and higher soil permeability. An analytical formula for dewatering-induced soil settlement was developed using a modified layered summation method that accounts for deformation coordination between soil layers and includes correction factors for unsaturated zones. Although this approach is limited by scale effects and simplified boundary conditions, the findings offer valuable insights into soil deformation mechanisms under the combined influence of excavation and dewatering. These results provide practical guidance for improving deformation control strategies in complex hydrogeological environments. Full article

Accelerometer-based wearables offer a cost-effective solution for managing match and training loads in invasion team sports. However, a multitude of acceleration-derived metrics, each employing different algorithms, has led to inconsistent and incomparable outcomes across studies and devices. This article reviews the mathematical procedures underlying whole-body mechanical load metrics, clarifies their conceptual differences, and proposes refinements to enhance standardization. Synthetic data were employed to investigate conceptual differences, while experimental accelerometric data (463 time series) from a set of elite handball training sessions (involving 16 players) were used to implement the corrected equations and analyze statistical relationships. Analysis of synthetic data revealed that derivative-based metrics, such as Jerk Modulus (typically referred to as Player Load) and corrected Accel’Rate (cAccel’Rate), tend to amplify noise compared to acceleration-based metrics, such as universal Dynamic Stress Load (uDSL) and Body Load. Experimental results indicated that when metrics were summed, their values were nearly identical. In time-series comparisons, Jerk Modulus and cAccel’Rate were predictably found to be nearly identical, while Body Load was the most distinct. Acceleration-based metrics are preferable to derivative-based ones. Sports scientists should lead the design and validation of such metrics, ensuring methodological rigor, transparency, and innovation while preventing commercial interests from introducing rebranded variables with undisclosed scaling factors and unclear calculations. Full article

While the development of sustainable construction materials, such as green concrete made from glass waste or recycled concrete aggregate, has been extensively researched, much of the existing work has focused narrowly on these two components. This limited scope highlights the need for further investigation to comprehensively address their drawbacks and expand the available knowledge base. Moreover, the current study uniquely emphasizes the shear response of green concrete, a critical aspect that has not been previously explored. Push-off shear samples made of green concrete, a mixture of recycled concrete, and glass waste, were built and subjected to direct shear loading testing to investigate shear response. In different proportions (0, 10, 25, 50, and 100%), fine glass aggregate is used in place of river sand. At different ratios (0, 10, 20, and 40%), coarse glass aggregate was substituted for coarse natural aggregate to form four mixtures. Additionally, recycled concrete and coarse glass aggregates were utilized instead of coarse natural aggregates. In the last group, coarse natural aggregate was substituted with recycled concrete aggregates in different proportions (0, 16, 40, and 80%). Measurements were made of the applied shear force and the sliding of the shear transfer plane during the test. The tested mixtures’ failure, shear strength, shear slip, shear stiffness, and shear stress slip correlations were examined. According to the results, all of the samples failed in the shear transfer plane. The shear strength of mixes containing 10, 25, 50, and 100% fine glass was, respectively, 12.8%, 14.7%, 29.5%, and 39% lower than the control combination without fine glass. As the amount of recycled glass and concrete materials grew, so did the shear slip at the shear transfer plane. In recent years, numerous studies have proposed formulas to predict the push-off shear strength of plain concrete, primarily using compressive strength as the key parameter—often without accounting for the influence of infill materials. The present study introduces an improved predictive model that incorporates the contents of recycled concrete aggregate, coarse glass aggregate, or fine glass aggregate as correction factors to enhance accuracy. Full article

The high-pile beam slab structure is a commonly employed design for riverbank wharves; however, the wharf structure may incur damage due to various factors during long-term operation, resulting in potential safety concerns. To illustrate this, an investigation was conducted on a high-pile beam slab wharf, which included on-site examination, testing, and large-scale three-dimensional numerical simulation. The effects of gravity, ship impact, earthquake, lateral impact, water, and crane change were considered to explore the causes of cracking in the wharf concrete components. The results indicated that crane modification significantly augmented loads, precipitating notable deformation (92% increase in maximum vertical displacement), and the maximum tensile stress exceeded concrete tensile strength. The inadequate thickness of the steel reinforcement protective layer caused concrete carbonation, steel exposure, and corrosion, reducing structural capacity. The presence of defects in the pile foundation has been shown to result in high stress concentrations, which can lead to deformation and damage. There was a 58% increase in vertical displacement in the concrete components above the affected area compared to intact piles. Based on analysis of the results, appropriate measures for strengthening and correction have been proposed to ensure the safety and durability of the wharf. A comprehensive multifactor evaluation and 3D simulation of the actual dimensions are recommended to ensure the safety of wharf structures. Full article

The increasing global demand for food caused by a growing world population has resulted in environmental problems, such as the destruction of ecologically significant biomes and pollution of ecosystems. At the same time, the intensification of crop production in modern agriculture has led to the extensive use of synthetic fertilizers to achieve higher yields. Although chemical fertilizers provide essential nutrients and accelerate crop growth, they also pose significant health and environmental risks, including pollution of groundwater and other bodies of water such as rivers and lakes. Soils that have been destabilized by indiscriminate clearing of vegetation undergo a desertification process that has profound effects on microbial ecological succession, impacting biogeochemical cycling and thus the foundation of the ecosystem. Tropical countries have positive aspects that can be utilized to their advantage, such as warmer climates, leading to increased primary productivity and, as a result, greater biodiversity. As an eco-friendly, cost-effective, and easy-to-apply alternative, biofertilizers have emerged as a solution to this issue. Biofertilizers consist of a diverse group of microorganisms that is able to promote plant growth and enhance soil health, even under challenging abiotic stress conditions. They can include plant growth-promoting rhizobacteria, arbuscular mycorrhizal fungi, and other beneficial microbial consortia. Bioremediators, on the other hand, are microorganisms that can reduce soil and water pollution or otherwise improve impacted environments. So, the use of microbial biotechnology relies on understanding the relationships among microorganisms and their environments, and, inversely, how abiotic factors influence microbial activity. The recent introduction of genetically modified microorganisms into the gamut of biofertilizers and bioremediators requires further studies to assess potential adverse effects in various ecosystems. This article reviews and discusses these two soil correcting/improving processes with the aim of stimulating their use in developing tropical countries. Full article

Spermatogenesis is a complex and highly regulated process involving the proliferation, differentiation, and apoptosis of germ cells. This process is controlled by various hormonal, genetic, and environmental factors, including temperature. In hormonal regulation, follicle-stimulating hormone (FSH), luteinizing hormone (LH), and testosterone (T) are essential for correct spermatogenesis development from the early stages and spermatogonia proliferation to germ cell maturation. Other hormones, like inhibin and activin, finely participate tuning the process of spermatogenesis. Genetic regulation involves various transcription factors, such as SOX9, SRY, and DMRT1, which are crucial for the development and maintenance of the testis and germ cells. MicroRNAs (miRNAs) play a significant role by regulating gene expression post-transcriptionally. Epigenetic modifications, including DNA methylation, histone modifications, and chromatin remodelling, are also vital. Temperature regulation is another critical aspect, with the testicular temperature maintained around 2–4 °C below body temperature, essential for efficient spermatogenesis. Heat shock proteins (HSPs) protect germ cells from heat-induced damage by acting as molecular chaperones, ensuring proper protein folding and preventing the aggregation of misfolded proteins during thermal stress. Elevated testicular temperature can impair spermatogenesis, increasing germ cell apoptosis and inducing oxidative stress, DNA damage, and the disruption of the blood–testis barrier, leading to germ cell death and impaired differentiation. The cellular mechanisms of germ cell proliferation, differentiation, and death include the mitotic divisions of spermatogonia to maintain the germ cell pool and produce spermatocytes. Spermatocytes undergo meiosis to produce haploid spermatids, which then differentiate into mature spermatozoa. Apoptosis, or programmed cell death, ensures the removal of defective germ cells and regulates the germ cell population. Hormonal imbalance, genetic defects, and environmental stress can trigger apoptosis during spermatogenesis. Understanding these mechanisms is crucial for addressing male infertility and developing therapeutic interventions. Advances in molecular biology and genetics continue to uncover the intricate details of how spermatogenesis is regulated at multiple levels, providing new insights and potential targets for treatment. Full article

This review evaluates the use of unmanned aerial vehicles (UAVs) in detecting and managing water stress in specialty crops through thermal, multispectral, and hyperspectral imaging. Based on 104 scholarly articles from 2012 to 2024, the review highlights the advantages, limitations, and evolution of these imaging systems. Vineyards are the most studied crops for precision irrigation compared to other crops. The paper traces the shift from standalone imaging to multi-sensor fusion approaches, integrating vegetation indices and machine learning models for improved accuracy, resolution, and real-time stress assessment. It also addresses knowledge gaps such as scalability, payload constraints, and computational demands. Issues like flight altitude, sensor angle, and lighting conditions can lead to data inconsistencies, affecting water stress detection and decision-making. Emerging technologies like LiDAR, AI, and machine learning are proposed to enhance UAV data processing and stress detection. Future research should focus on developing automated data correction, multi-sensor fusion, and AI-driven real-time analysis to address sensor calibration and environmental factors. The review also advocates for integrating UAV data with satellite and ground sensors into smart irrigation systems to create a multi-scale monitoring framework, thereby advancing precision agriculture and water resource management. Full article

Background/Objectives: Patients with hematologic malignancies undergo prolonged, intensive treatments involving frequent hospitalizations and experience debilitating side effects. Consequently, they are at increased risk of developing symptoms of depression, anxiety, and stress, which can undermine their quality of life. However, there is a scarcity of instruments validated for the simultaneous assessment of depression, anxiety, and stress within hematologic cancer populations. The aim of this study is to examine the construct validity, convergent and discriminant validity, and reliability of the Depression Anxiety Stress Scales (DASS-42 and DASS-21) among hematologic cancer patients. Methods: We collected data from 452 hematologic cancer patients across three studies. Results: Confirmatory factor analyses indicated that the theoretical correlated three-factor model and bifactor model for DASS-42 and DASS-21 responses were sufficient to explain the underlying factor structure of the scales in hematologic cancer patients. However, the bifactor model for DASS-42 and DASS-21 fit better with the data compared to the theoretical correlated three-factor model. In addition, we found the correlated three-factor model and the bifactor structure to exhibit scalar measurement invariance across gender for DASS-42 and DASS-21. DASS-42 and DASS-21 subscales demonstrated weak to strong negative correlations with measures of psychological well-being (happiness, well-being, life satisfaction) and strong positive correlations with measures of similar constructs (depression, anxiety, and stress), thereby supporting their convergent and discriminant validity with theoretically and empirically expected correlations with external criteria. The reliability analyses demonstrated that both DASS-42 and DASS-21 subscales exhibited strong internal consistency and test–retest reliability when assessing symptoms of depression, anxiety, and stress among patients with hematologic malignancies. Moreover, the item-scale convergent and discriminant validity analyses demonstrated that items exhibited higher corrected item–total correlations with their intended subscales than with other subscales across the DASS-42 and DASS-21, providing evidence for the distinct measurement properties of each subscale. Conclusions: The findings suggest that the DASS-42 and DASS-21 are psychometrically robust instruments for use in Turkish hematologic cancer patients. Full article

Autism spectrum disorder (ASD) is a neurodevelopmental disorder that affects over 2% of the population worldwide and is characterized by repetitive behaviors, restricted areas of interest, deficits in social communication, and high levels of anxiety. Currently, there are no known effective treatments for the core features of ASD. The previous literature has established erythropoietin (EPO) as a promising antidepressant, working as a potent neurogenic and neurotrophic agent with hematopoietic side effects. Carbamoylated erythropoietin (CEPO), a chemically engineered non-hematopoietic derivative of EPO, appears to retain the neuroprotective factors of EPO without the hematologic properties. Recent evidence shows that CEPO corrects stress-related depressive behaviors in BALB/cJ (BALB) mice, which also have face validity as an ASD mouse model. We investigated whether CEPO can recover deficient social and anxiety-related behavioral deficits compared to C57BL/6J controls. After administering CEPO (40 μg/kg in phosphate-buffered saline) or vehicle over 21 days, we analyzed the mice’s performance in the three-chamber social approach, the open field, the elevated plus maze, and the Porsolt’s forced swim tasks. CEPO appeared to correct sociability in the three-chamber social approach task to C57 levels, increasing the amount of time the mice interacted with novel, social mice overall rather than altering the overall amount of exploratory activity in the maze. Consistent with this finding, there was no concomitant increase in the distance traveled in the open field, nor were there any alterations in the anxiety-related measures in the task. On the other hand, CEPO administration improved exploratory behavior in the elevated plus maze. This study marks the first demonstration of the benefits of a non-erythropoietic EPO derivative for social behavior in a mouse model of autism and merits further investigation into the mechanisms by which this action occurs. Full article