Search Results (4,167)

In the case of waveguide-based devices, once they are fabricated, their optical properties are already determined and cannot be dynamically controlled, which limits their applications in practice. In this paper, an isosceles triangular-coupling structure which consists of an isosceles triangle coupled with a two-bus waveguide is proposed and researched numerically and theoretically. The coupled mode theory (CMT) is introduced to verify the correctness of the simulation results, which are based on the finite difference time domain (FDTD). Due to the existence of the side mode and angular mode, the transmission spectrum presents two high transmittance peaks and two low transmittance peaks. In addition, the four transmission peaks exhibit different variation trends when the dimensions of the isosceles triangle are changed. The liquid crystal (LC) materials comprise anisotropic uniaxial crystal and exhibit a remarkable birefringence effect under the action of the external field. When the isosceles triangle coupling structure is filled with LC, the refractive index of the liquid crystal can be changed by changing the applied voltage, thereby achieving the function of an optical switch. Within a certain range, a linear relationship between refractive index and applied voltage can be obtained. Moreover, the proposed structure can be applied to biochemical sensing to detect glucose concentrations, and the sensitivity reaches as high as 0.283 nm·L/g, which is significantly higher than other values reported in the literature. The triangular coupling structure has advantages such as simple structure and ease of manufacturing, making it an ideal choice for the design of high-performance integrated plasmonic devices. Full article

The global trend of rapid economic development and urbanization has created questions regarding the quality of the environment. In the group of emerging economies (E7), environmental challenges have intensified due to specific dynamics unique to these nations. This research is focused on determining the influence of urbanization (UBNZ), renewable energy (RWNE), capital formation (CPFR), foreign direct investment (FDIN), and natural resources (NTRR) on the ecological footprint (ECLF) of the E7 economies. The study employs the Panel Autoregressive Distributed Lag (PMG-ARDL) approach to examine these relationships, utilizing data spanning the period of 1990–2022. The results reveal that a 1% increase in the CPFR, NTRR, and UBNZ leads to increases in the ECLF of 0.0581%, 0.0263%, and 0.0299%, respectively. Conversely, a 1% increase in RWNE and FDIN reduces the ECLF by 0.0207% and 0.0556%, respectively, in the E7 economies. The study’s findings are further validated through robustness testing via the fully modified ordinary least squares (FMOLS) method. The study concludes with actionable policy recommendations aimed at enhancing environmental quality within these economies. These recommendations include promoting renewable energy adoption, attracting environmentally sustainable foreign investments, and implementing strategies to manage urbanization and natural resource use effectively. Full article

Contrails, or condensation trails, left by aircraft, significantly contribute to global warming by trapping heat in the Earth’s atmosphere. Despite their critical role in climate dynamics, the environmental impact of contrails remains underexplored. This research addresses this gap by focusing on the use of CubeSats for real-time contrail monitoring, specifically over major air routes such as the Europe–North Atlantic Corridor. The study proposes a 3 × 3 CubeSat constellation in highly eccentric orbits, designed to maximize coverage and data acquisition efficiency. Simulation results indicate that this configuration can provide nearly continuous monitoring with optimized satellite handovers, reducing blackout periods and ensuring robust multi-satellite visibility. A machine learning-based system integrating space-based humidity and temperature data to predict contrail formation and inform flight path adjustments is proposed, thereby mitigating environmental impact. The findings emphasize the potential of CubeSat constellations to revolutionize atmospheric monitoring practices, offering a cost-effective solution that aligns with global sustainability efforts, particularly the United Nations Sustainable Development Goal 13 (Climate Action). This research represents a significant step forward in understanding aviation’s non-CO₂ climate impact and demonstrates the feasibility of real-time contrail mitigation through satellite technology. Full article

Self-organization in complex systems is a process associated with reduced internal entropy and the emergence of structures that may enable the system to function more effectively and robustly in its environment and in a more competitive way with other states of the system or with other systems. This phenomenon typically occurs in the presence of energy gradients, facilitating energy transfer and entropy production. As a dynamic process, self-organization is best studied using dynamic measures and principles. The principles of minimizing unit action, entropy, and information while maximizing their total values are proposed as some of the dynamic variational principles guiding self-organization. The least action principle (LAP) is the proposed driver for self-organization; however, it cannot operate in isolation; it requires the mechanism of feedback loops with the rest of the system’s characteristics to drive the process. Average action efficiency (AAE) is introduced as a potential quantitative measure of self-organization, reflecting the system’s efficiency as the ratio of events to total action per unit of time. Positive feedback loops link AAE to other system characteristics, potentially explaining power–law relationships, quantity–AAE transitions, and exponential growth patterns observed in complex systems. To explore this framework, we apply it to agent-based simulations of ants navigating between two locations on a 2D grid. The principles align with observed self-organization dynamics, and the results and comparisons with real-world data appear to support the model. By analyzing AAE, this study seeks to address fundamental questions about the nature of self-organization and system organization, such as “Why and how do complex systems self-organize? What is organization and how organized is a system?”. We present AAE for the discussed simulation and whenever no external forces act on the system. Given so many specific cases in nature, the method will need to be adapted to reflect their specific interactions. These findings suggest that the proposed models offer a useful perspective for understanding and potentially improving the design of complex systems. Full article

Probiotics, due to their multifaceted benefits to the host, are essential in medicine, agriculture, and aquaculture. The mechanisms of their action at the molecular level are complex and less explored. Both previous research and our own investigations have highlighted that incorporating probiotics into the feed of commercial fish can increase growth and influence the expression of genes related to stress and immunity. Additionally, probiotics with antioxidant properties often exert systemic effects. The aim of this work was to explore possible mechanisms of probiotic effects on stress-related proteins in African catfish C. gariepinus using molecular docking and dynamics approaches. Stress biomarker proteins such as catalase, cytochrome P450, HSP70, metallothionein 1, and superoxide dismutase were evaluated for possible interactions with bioactive non-ribosomal peptides (NRPs) from Bacillus subtilis R5, used as ligands. The study involved molecular docking and dynamics interactions between proteins and NRPs. The results of molecular docking and dynamics reveal multiple bindings between proteins and ligands, forming stable complexes, which may explain the mechanisms of action of probiotics and their particularly positive effects, such as the reduction in stress levels, which was demonstrated in the clarium catfish model in our previous work. Non-ribosomal peptides synthesized by probiotics may influence key signalling pathways underlying antioxidant and antimutagenic properties. Full article

Identifying the drivers of land use and cover change (LUCC) is crucial for sustainable land management. However, understanding spatial differentiation and conducting inter-regional comparisons of these drivers remains limited, particularly in regions like Malaysia, where complex interactions between human activities and natural conditions pose significant challenges. This study presents a novel analytical framework to examine the spatial variations and complexities of LUCC, specifically addressing the spatiotemporal patterns, driving factors, and pathways of LUCC in Malaysia from 2010 to 2020. Integrating the land use transfer matrix, GeoDetector model, and Structural Equation Modeling (SEM), we reveal a significant expansion of farmland and urban areas alongside a decline in forest cover, with notable regional variations in Malaysia. Human-driven factors, such as population growth and economic development, are identified as the primary forces behind these changes, outweighing the influence of natural conditions. Critically, the interactions among these drivers exert a stronger influence on LUCC dynamics in Malaysia than any single factor alone, suggesting increasingly complex LUCC predictions in the future. This complexity emphasizes the urgency of proactive, multifaceted, and region-specific land management policies to prevent irreversible environmental degradation. By proposing tailored land management strategies for Malaysia’s five subnational regions, this study addresses spatial variations in drivers and climate resilience, offering a strategic blueprint for timely action that can benefit Malaysia and other regions facing similar challenges in sustainable land management. Full article

Safety climate has been extensively studied using survey-based approaches, providing significant insights into safety perceptions and behaviors. However, understanding its dynamics in construction projects requires methods that address temporal and trade-specific variability. This study employs a longitudinal, mixed-methods design to explore safety climate dynamics. Quantitative data analyzed with ANOVA revealed stable overall safety climate scores across project phases, while Item Response Theory (IRT) identified survey items sensitive to safety climate changes. Positive perceptions were associated with management commitment and regular safety meetings, while negative perceptions highlighted challenges such as workplace congestion and impractical safety rules. Qualitative data from semi-structured interviews uncovered trade-specific and phase-specific safety challenges, including issues tied to site logistics and workforce dynamics. For instance, transitioning from structural to interior work introduced congestion-related risks and logistical complexities, underscoring the need for phase-adapted strategies. This combination of quantitative stability and qualitative variability provides empirical evidence of safety climate dynamics in construction. The findings emphasize the importance of tailoring safety interventions to address trade-specific and phase-specific risks. This study advances the understanding of the safety climate in dynamic work environments and offers actionable recommendations for improving construction safety management through targeted, proactive strategies. Full article

Background/Objectives: Pyruvate kinase M2, a central regulator of cancer cell metabolism, has garnered significant attention as a promising target for disrupting the metabolic adaptability of tumor cells. This study explores the potential of the Mannich base derived from lawsone (MB-6a) to interfere with PKM2 enzymatic activity both in vitro and in silico. Methods: The antiproliferative potential of MB-6a was tested using MTT assay in various cell lines, including SCC-9, Hep-G2, HT-29, B16-F10, and normal human gingival fibroblast (HGF). The inhibition of PKM2 mediated by MB-6a was assessed using an LDH-coupled assay and by measuring ATP production. Docking studies and molecular dynamics calculations were performed using Autodock 4 and GROMACS, respectively, on the tetrameric PKM2 crystallographic structure. Results: The Mannich base 6a demonstrated selective cytotoxicity against all cancer cell lines tested without affecting cell migration, with the highest selectivity index (SI) of 4.63 in SCC-9, followed by B16-F10 (SI = 3.9), Hep-G2 (SI = 3.4), and HT-29 (SI = 2.03). The compound effectively inhibited PKM2 glycolytic activity, leading to a reduction of ATP production both in the enzymatic reaction and in cells treated with this naphthoquinone derivative. MB-6a showed favorable binding to PKM2 in the ATP-bound monomers through docking studies (PDB ID: 4FXF; binding affinity scores ranging from −6.94 to −9.79 kcal/mol) and MD simulations, revealing binding affinities stabilized by key interactions including hydrogen bonds, halogen bonds, and hydrophobic contacts. Conclusions: The findings suggest that MB-6a exerts its antiproliferative activity by disrupting cell glucose metabolism, consequently reducing ATP production and triggering energetic collapse in cancer cells. This study highlights the potential of MB-6a as a lead compound targeting PKM2 and warrants further investigation into its mechanism of action and potential clinical applications. Full article

This study explores the applications of extended Gauss–Hertz variational principles to determine the evolution of complex systems under the influence of impulse actions, coherent accelerations, and their application to electrophysical systems with fractal elements. Impulsive effects on systems initiate coherent accelerations (including higher-order accelerations, such as modes with intensification), leading to variations in connections, structure, symmetry, and inertia; the emergence of coherence; and the evolution of fractal elements in electrophysical circuits. The combination of results from the non-local Vlasov theory and modifications to the Gauss–Hertz principle allows for the formulation of a variational principle for the evolution of fractal systems. A key feature of this variational principle is the ability to simultaneously derive equations for both the system’s dynamics and the self-harmonizing evolution of its internal symmetry and structure (e.g., fractal parameters). Full article

Brazil’s wind power industry (WPI) has thrived since the early 2000s, driven by a successful auction-based expansion plan. However, the recent rise of cost-competitive solar power and policy shifts favoring other energy sources, such as natural gas, have created uncertainty about the future of wind energy in Brazil and reduced the wind sector’s legitimacy. Additionally, the cancellation of wind power auctions and support for other energy sources (evidenced by the new regulation for natural gas) has sent mixed signals to the market. These actions have sparked concerns regarding the future trajectory of the WPI. This paper focuses on the long-term effects of this energy policy decision on the so-called legitimacy function of the technological innovation systems (TIS) for the case of WPI in Brazil. The study aims to identify challenges arising from the growing appeal of solar power that may hinder wind energy adoption and to offer policy recommendations to strengthen the wind sector’s legitimacy. A system dynamics model is proposed to quantify such impacts in the long run, showing the interactions between the wind power capacity, wind generation costs, and the legitimacy function of the TIS. Results show the importance of policy consistency and institutional support in fostering a stable environment for renewable energy technologies like wind power to flourish. Full article

The adenosine A1 receptor (A₁R) is a promising target for pain treatment. However, the development of therapeutic agonists is hampered by adverse effects, mainly including sedation, bradycardia, hypotension, or respiratory depression. Recently discovered molecules able to overcome this impediment are the positive allosteric modulator MIPS521 and the A1R-selective agonist BnOCPA, which are both potent and powerful analgesics with fewer side effects. While BnOCPA directly activates the A₁R from the canonical orthosteric site, MIPS521 binds to an allosteric site, acting in concert with orthosteric adenosine and tuning its pharmacology. Given their overlapping profile in pain models but distinct mechanisms of action, we combined pharmacology and microsecond molecular dynamics simulations to address MIPS521 and BnOCPA activity and their reciprocal influence when bound to the A1R. We show that MIPS521 changes adenosine and BnOCPA G protein selectivity in opposite ways and propose a structural model where TM7 dynamics are differently affected and involved in the G protein preferences of adenosine and BnOCPA. Full article

Better understanding the complex mechanisms underlying the variations in crop residue burning (CRB) intensity and patterns is crucial for evaluating control strategies and developing sustainable policies aimed at the efficient recycling of crop residues. However, the intricate interplay between the CRB practices, climate variability, and human activities poses a significant challenge in this endeavor. Here, we utilize the high spatiotemporal resolution of satellite observations to characterize and explore the dynamics of summer CRB in North China at multiple scales. Between 2003 and 2012, there was a significant intensification of summer CRB in North China, with the annual number of burning spots increasing by an average of 499 (95% confidence interval, 252–1426) spots/year. However, in 2013, China promulgated the stringent Air Pollution Prevention and Control Action Plan, which led to a rapid decrease in the intensity of summer CRB. Local farmers also adjusted their burning practices, shifting from concentrated and intense burning to a more dispersed and uniformly intense approach. Between 2003 and 2020, the onset of summer CRB shifted earlier in North China by 0.75 (0.5–1.1) days/year, which is attributed to the combined effects of climate change and anthropogenic controls. Specifically, the onset time is found to be significantly and negatively correlated with spring temperature anomalies and positively correlated with anomalies in the number of spring frost days. Climate change has led to a shortened crop growing season, resulting in an earlier start to summer CRB. Moreover, the enhanced anthropogenic controls on CRB expedited this process, making the trend of an earlier start time even more pronounced from 2013 to 2020. Contrary to the earlier onset of summer CRB, the termination of local wheat residue burning experienced a notable delay by 1.0 (0.8–1.4) days/year, transitioning from mid-June to early July. Full article

Despite the increasing concerns regarding meeting the world’s future food demand, there is still a substantial quantity of food loss and waste (FLW), particularly concerning fruits and vegetables. In the case of Kermanshah province, inefficiencies within the leafy vegetable supply chpain (LVSC) contribute to an alarming annual waste of 39% of leafy vegetables. Although several studies have proposed strategies and recommendations for mitigating this waste, the actual impact of these interventions on reducing FLW has not been thoroughly examined or quantified. Using System Dynamic Modeling, this study offers a novel approach to quantify the impact of interventions on waste reduction. The quantification results reveal four key interventions reducing vegetable waste at the production stage: biotic (31.2%) and abiotic stress control (14.4%), improved educational services (23.2%), and access to quality inputs (15.2%). Furthermore, the results suggest that early-stage factors in the LVSC play a crucial role in determining waste accumulation in later stages. Improvements in packaging facilities and cold supply chain infrastructure, along with better coordination and information sharing among stakeholders at the market stage, significantly help reduce waste. Additionally, effective planning for household food shopping is emphasized as a crucial strategy for minimizing waste at the consumption stage. This holistic approach focuses on the interconnectedness of actions across various stages of the supply chain and their combined effect on decreasing the overall waste of leafy vegetables. Full article

Dynamic facades allow for effective climate adaptability, representing a new trend in future building envelope design. Present research on dynamic facades often focuses solely on certain aspects of the built environment or relies entirely on simulation outcomes. Meanwhile, the real-time changing nature of dynamic facades poses challenges in accurately simulating these schemes. Therefore, it remains essential to quantify the energy consumption performances of different types of dynamic facades and their influence on the indoor environment comfort in response to ventilation, light, and thermal environment to improve energy savings. This study uses an energy management system to simulate the ability of five dynamic facades—an intelligent ventilated facade, a dynamic exterior shading, a dynamic interior shading, a buffer layer, and phase-change material (PCM) facades—to provide adequate comfort and reduce energy consumption in four climate zones in China. The simulation model of a nearly net-zero energy Solar Decathlon house “Nature Between” was validated with experimental data. Among the five dynamic facades, the energy-saving efficiency of intelligent ventilation was highest, followed by exterior shading. Compared with houses without dynamic facades, the use of the dynamic facades reduced energy consumption (and annual glare time) by 19.87% (90.65%), 22.37% (74.84%), 15.19% (72.09%), and 9.23% (75.53%) in Xiamen, Shanghai, Beijing, and Harbin, respectively. Findings regarding the dynamic facade-driven energy savings and favorable indoor environment comfort provide new and actionable insights into the design and application of dynamic facades in four climate regions in China. Full article

Wetlands play a crucial role in carbon sequestration. The integration of wetland carbon dynamics into landscape architecture, however, has been challenging, mainly due to gaps between scientific knowledge and landscape practice norms. While the carbon performance of different wetland types is well established in the ecological sciences literature, our study pioneers the translation of this scientific understanding into actionable landscape design guidance. We achieve this through a comprehensive, spatially explicit analysis of wetland carbon dynamics using 2024 National Wetlands Inventory data and other spatial datasets. We analyze carbon flux rates across 13 distinct wetland types in Illinois to help quantify useful information related to designing for carbon outcomes. Our analysis reveals that in Illinois, bottomland forests function as primary carbon sinks (709,462 MtC/year), while perennial deepwater rivers act as significant carbon emitters (−2,573,586 MtC/year). We also identify a notable north–south gradient in sequestration capacity, that helps demonstrate how regional factors influence wetland and other stormwater management design strategies. The work provides landscape architects with evidence-based parameters for evaluating carbon sequestration potential in wetland design decisions, while also acknowledging the need to balance carbon goals with other ecosystem services. This research advances the profession’s capacity to move beyond generic sustainable design principles toward quantifiable climate-responsive solutions, helping landscape architects make informed decisions about wetland type selection and placement in the context of climate change mitigation. Full article