The effect of thermal stress on beneficial symbiosis, in the face of rapid climate change, remains poorly understood. We investigate this using the model system,Euprymna scolopes(Es), the Hawaiian bobtail squid, and its bioluminescent symbiont,Vibrio fischeri(Vf), which enables the squid to camouflage itself through counter-illumination. Successful colonization of the squid by Vf must occur hours after hatching and is mediated by fluid flow due to respiration within the squid mantle cavity. To study this process, we develop a mathematical model using the method of regularized stokeslets to simulate the flow and resulting bacterial trajectories within the squid. We explore how thermal stress, mediated by physiological changes in respiration, ciliary dynamics and internal geometry, affects early colonization by analysing the time bacteria spend in regions crucial to the establishment of symbioses in these simulations. A variance-based sensitivity analysis of physiologically relevant parameters on these metrics demonstrated that changes in the breath cycle significantly affect and reduce the time bacteria spend in the critical zone within the squid, hindering colonization.

The durability of concrete structures in salt lake regions is severely threatened by sulfate attack. This study investigated the effect of incorporating limestone powder (LP) on the sulfate resistance of sulfoaluminate cement (SAC) concrete under a semi-immersed environment. Concrete specimens with varying LP dosages (0%, 5%, 10%, 15%, and 20% by cement mass) were exposed to a 5% Na₂SO₄ solution. The deterioration was evaluated through macroscopic properties (compressive strength, mass, and relative dynamic elastic modulus) and microstructural characterization (XRD, SEM, MIP) over 180 days. Results indicated that the performance was highly dependent on the LP content and the exposure zone. Specimens with 5–10% LP exhibited superior resistance, demonstrated by the most stable mass and the smallest reduction in compressive strength (5.16% and 5.03%, respectively) in the critical crystallization zone. Microstructural analysis revealed that, at optimal dosages (5–10%), LP acted as a micro-filler and participated in the hydration process, leading to a denser matrix with fewer harmful pores and microcracks. However, a higher LP content (15–20%) introduced a dilution effect, increasing porosity and compromising the durability. The findings confirm that an incorporation of 5–10% LP is a viable strategy for producing high-performance sulfate-resistant SAC concrete in aggressive environments.

Unraveling nitrogen transport mechanisms and interface transfer zones within the surface water-groundwater continuum for targeted agricultural management.

Seagrass meadows support biodiversity, coastal protection and blue carbon services but are declining globally, with nutrient enrichment a pervasive driver of eutrophication. Effective management depends on detecting eutrophication before structural collapse occurs, yet widely used tissue nitrogen (N) benchmarks for seagrasses have never been formally validated. We assessed nutrient exposure and ecological condition across nine seagrass meadows in Northern Ireland using tissue carbon, nitrogen and phosphorus content, stoichiometric ratios and stable isotopes (δ13C, δ15N), and tested how tissue nitrogen relates to Zostera marina biomass at Northern Hemisphere scale by integrating regional, UK and global datasets. All Northern Ireland meadows exceeded the global 1.8% tissue nitrogen benchmark, indicating pervasive anthropogenic nitrogen exposure even within Marine Protected Areas. The combined datasets revealed a strong, nonlinear decline in Z. marina biomass with increasing tissue nitrogen that was consistent across sites. Biomass began to decline significantly above 1.8% N, identifying this value as the onset of functional degradation. The rate of biomass loss increased rapidly with further enrichment and peaked at 2.8% N, defining a critical point at which additional nitrogen causes the greatest marginal loss of seagrass biomass. These results provide quantitative support for existing tissue nitrogen benchmarks and refine their ecological interpretation, highlighting 1.8% N as an early-warning threshold and2.8% N as a high-risk range for rapid biomass loss. Tissue nitrogen therefore represents a integrative, biologically meaningful indicator of eutrophic stress applicable for management and restoration prioritisation in seagrass ecosystems.

ABSTRACT Eco‐geology studies interactions between Earth's surface multi‐sphere structures and their feedback mechanisms under natural and anthropogenic influences. Eco‐geological environment elements maintain organic interconnections and dynamic equilibrium, with stability being crucial for human–nature harmony in urban agglomerations. However, few studies have focused on the integrated and comprehensive assessment of regional eco‐geological environments. Therefore, quantitatively analyzing the evolution of the eco‐geological environment in urban agglomerations and its driving mechanisms is of great significance for long‐term urban planning. Taking the Beijing‐Tianjin‐Hebei region as an example, this study developed a comprehensive evaluation model integrating ecosystem services, ecosystem vulnerability, and geological environment sensitivity and established an Eco‐Geological Environmental Security Index. In addition, spatial statistical methods were employed to uncover the driving mechanisms of eco‐geological environment evolution under multi‐factor causal cascades and interactions. The self‐organizing map (SOM) algorithm was further applied for eco‐geological environment zoning. Results showed the BTH's eco‐geological environment exhibited a spatial pattern of lower values in the northwest and higher values in the southeast, with an overall improving trend. The eco‐geological environment in the northwestern desert, southwestern mountainous, and southeastern plains was predominantly influenced by natural factors, while the northeast was significantly affected by human activities. Furthermore, SOM‐based clustering identified four distinct zones: Northwestern Long‐term Consolidation Zone, Taihang‐Yanshan Key Conservation Zone, Southeastern Stable Development Zone, and Critical Fragile Zone of the Mountain‐Plain Transition Belt. This framework provides a novel methodology for eco‐geology research and supports sustainable development of eco‐geological environments in large urban agglomerations.

The laryngotracheal junction (LTJ) is a functionally critical zone, due to its narrow anatomy, complex airflow dynamics, and proximity to the glottis and cricoid cartilage. Extensive stenoses, cricoid defects, and stomal anterior wall loss frequently exceed the possibilities of conventional resection and reconstruction. To outline the current role of microvascular reconstruction at the LTJ, with a focus on indications, techniques, and limitations from the perspective of otolaryngology and thoracic surgery. Narrative literature review of clinically established flap reconstruction techniques at the LTJ, including recent case series and key publications. For short, non-pretreated defects, cricotracheal resection and segmental tracheal resection with end-to-end anastomosis remain the standard of care. Microvascular reconstructions are mainly used for long, circumferential LTJ defects, extensive cricoid loss, previously irradiated or multiply operated regions, and complex treatment interventions. The radial forearm free flap is currently the best-established option for long tracheal and laryngotracheal defects and can be combined with cartilage reinforcement or a mucosal lining. Osseous flaps such as the medial femoral condyle flap and the thoracodorsal artery scapular tip flap allow larynx-preserving reconstruction, with restoration of a stable ring or posterior framework in selected cases. Prefabricated constructs, ALT-based flaps, jejunal grafts, and pedicled flaps play an adjunctive role in borderline and salvage situations. Microvascular reconstruction extends the therapeutic spectrum for LTJ surgery beyond conventional resection techniques and can provide a functional airway in highly complex situations and with acceptable morbidity. Given the limited evidence base from case series, interdisciplinary planning and centralisation of these procedures in experienced centres are essential.

Abstract The reuse of recycled materials in transportation infrastructure has gained significant popularity in recent years. Particularly, recent studies have explored the use of coal wash and rubber crumbs mixtures (CWRC) to create a synthetic, energy-absorbing railway capping layer, offering a sustainable and cost-effective alternative to traditional materials. Although previous studies have examined the mixture’s deformation characteristics, particle breakage, damping properties, and resilient behaviour under cyclic loading, its fatigue behaviour remains largely unexplored. The current research aims to investigate the effect of the applied cyclic deviator stress on the fatigue behaviour of this waste mixture, by evaluating permanent deformation, particle breakage, resilient modulus, and shear modulus through a series of cyclic triaxial tests. Three distinct zones, namely the plastic shakedown zone, critical dynamic stress zone, and low-cycle fatigue zone, are identified based on the accumulated permanent deformation and the stress–life diagram. A detailed analysis of particle breakage, resilient modulus, and shear modulus associated with these three zones is also conducted. The findings of this study will significantly impact future track design by integrating the concept of fatigue under cyclic loading based on plasticity and yield envelopes.

Meeting rising food demand under intensifying climate variability, soil degradation, and groundwater decline requires agriculture to produce more with less freshwater. We advance critical zone agrohydrology (CZA) as a unifying framework that treats agricultural landscapes as human-managed critical zones—coupled systems extending from canopy to bedrock and operating from seasons to decades. CZA is organized around the four deeps (deep time, deep depth, deep coupling, and deep practice) and operationalized through a 5M cycle of measuring, mapping, monitoring, modeling, and managing. This perspective expands conventional agrohydrology by accounting for long-term soil change, subsurface storage and flow, biogeochemical feedbacks, and human decision-making, thereby linking field efficiency with basin sufficiency. We illustrate implications for multifunctional soil management, nutrient-loss control, salinity rehabilitation, drought resilience, managed aquifer recharge, and cross-scale governance. By reframing agriculture as a potential contributor to aquifer stability, water quality, carbon storage, biodiversity, and durable productivity, CZA offers a practical pathway toward more resilient and basin-aware agricultural water management.

Toluene, as a common organic solvent in academic laboratories in university campuses, poses potential exposure concerns to students and staff in university campuses. Hence, by using a computational fluid dynamics simulation, we investigated the dispersion characteristics of toluene at a campus in Guangzhou under meteorological conditions and the impact of newly constructed buildings on toluene concentrations. The numerical simulation results reveal that toluene is readily accumulated in the free movement area under the prevailing east wind, in the administrative area under the prevailing north-northeast wind, and in the teaching area under the prevailing south wind. Therein, the teaching buildings (TB3-TB6) possess the highest average concentration of toluene compared with other functional areas. In the presence of newly constructed buildings, the toluene concentrations are decreased under the south-southeast wind but are aggravated under the southeast wind. As the height increases, under south-southeast winds, the merging of vortex structures continuously reduces toluene concentrations at TB3 and TB4 and the expansion of the wake region rebounds the toluene pollution at TB5 and TB6; under southeast winds, the expanding vertical vortex structures aggravate toluene pollution at TB3 and TB5 but attenuate toluene pollution at TB4 and TB6. Our results reveal that the teaching areas of the target campus represent a critical zone for potential student exposure during summer and require particular attention. This study provides new insights into the coupled effects of prevailing wind conditions and campus morphology on VOC dispersion characteristics and improves the understanding of airflow pollutant interactions in complex campus environments.

Graded ventilation with primary supply air confined in critical demand zone by overcoming negative and positive thermal buoyancies

Nanoparticle-rhizosphere crosstalk: Insights into transformation, microbial interaction, plant uptake and translocation.

Drivers, Trade-offs and Synergies of Ecosystem Services in Ecological Security Barrier Zones: Implications for Ecological Management.

To clarify the roof shear slip movement mechanism of roadways subjected to strong dynamic pressure during ultrathick coal seam mining, this study investigates the return airways of the 5107 fully mechanized top-coal caving (FMTC) panel at Yushupo Mine as a case study. The deformation characteristics and structural instability of surrounding rock in high-stress roadways were systematically analyzed through field observations, theoretical modeling, numerical simulation, and engineering verification. Based on the limit equilibrium theory, a dynamic pressure thick coal seam roadway roof shear slip mechanics model was established, and the spatial distribution of the shear slip zone and the minimum effective anchorage thickness were quantitatively determined. A new integrated collaborative control strategy of "bending resistance shear control displacement" was proposed for ultra thick coal seam roadway, and on-site practice was carried out. The results indicate that the roof shear slip surface initiates approximately 0.53m from the roadway rib, propagates toward the centerline, and reaches its maximum development at a height of 4.58m, located only 0.06m from the centerline. The pronounced reduction in safety factors near the centerline reveals a critical zone highly susceptible to roof instability induced by strong mining-induced dynamic pressure. Discrete element method (DEM) simulations were employed to quantify the effects of key controlling parameters, including roof coal cohesion, parting layer position, and support configurations, on the evolution of roof shear slip movement. On this basis, a coordinated control strategy integrating bending resistance, shear strengthening, and displacement control was proposed. A full-length anchored cable reinforcement scheme tailored for ultrathick coal seams was developed and implemented in the field. Monitoring results demonstrate that the proposed support system effectively controls surrounding rock deformation, optimizes bolt-cable load transfer, suppresses bed separation, and significantly enhances roof stability. Field application confirms its effectiveness in mitigating large deformation in surrounding rock and ensuring the safe and efficient mining of ultrathick coal seams.

Microbial communities in the critical zone drive key geochemical processes, but many subsurface habitats remain poorly characterized. Ghost-rock karst systems in particular represent unexplored microbial niches. Here, we provide the first genome-resolved metagenomic comparison of ghost-rock and groundwater microbial communities from the Sterkfontein karst system (South Africa). Ghost-rock and groundwater communities host distinct taxonomic and metabolic assemblages. Groundwater communities are dominated by chemolithotrophs capable of oxidizing sulfur- and nitrogen-bearing compounds, and by heterotrophs degrading refractory, plant-derived organic matter. In contrast, primary producers in ghost-rocks likely rely on atmospheric chemosynthesis via trace gas oxidation, while glycogen metabolism and necromass recycling point to adaptations to oligotrophic and fluctuating hydrological conditions. Groundwater taxa with metal-interacting pathways may initiate bedrock colonization via metal oxidation, whereas ghost-rock communities include potential metal reducers that could drive iron and manganese oxide dissolution and influence trace element mobility. Together, these results underscore ghost-rocks as active microbial and geochemical hot spots within karst systems that may play a non-negligible role on biomineralization/bioweathering processes and on shaping (sub)terrestrial landscapes and global biogeochemical cycles.

This study investigates internal erosion in gap-graded gravelly soils, focusing on the critical fine content transition zone (30-35%). By integrating µ-CT imaging, geometric criteria analysis, and a novel predictive model based on the graded erosion principle, we demonstrate that fine particle content governs the transition between suffusion and piping erosion modes. Experimental results reveal that exceeding the 30-35% threshold shifts the soil fabric from a stable coarse-grained skeleton to an "over-filled" structure, where coarse particles float within a fine-dominated matrix, drastically increasing piping susceptibility. A multi-criteria assessment framework validates the limitations of traditional geometric criteria (e.g., Cu, Kenney & Lau) for transitional soils, while the grading entropy criterion offers enhanced robustness. The proposed graded erosion model successfully predicts particle size distribution evolution toward stable Fuller limits and porosity changes by incorporating particle-size-sensitive erosion rates with physical thresholds. This integrated methodology advances the understanding and prediction of internal erosion in gap-graded soils, supporting the design of resilient geotechnical structures and improving infrastructure risk assessment.

This study investigates the influence of specific heat input and weld configuration on heat affected zone hardness and residual stress of S960MC high strength steel welds. In total, five types of weld samples were manufactured by Tungsten Inert Gas (TIG) autogenous welding and Metal Active Gas (MAG) butt welding to simulate the effect of increasing heat input and constraining the relative motion of welded parts during the heating and cooling phase. The obtained results show that the highest axial tensile residual stresses with magnitude above 900 MPa, combined with a hardness drop in a range from 13 up to 18%, occur mostly in the sub-critical heat affected zone, making it the critical zone of the weld. Increasing the heat input during welding does not have a simple correlation with generating more residual stresses and the trends obtained on the surface are different from results evaluated at a depth of 0.2 mm. Restraining the relative part motion during the welding affects mostly the tangential residual stresses, causing an increase in their tensile magnitude localized in the middle of the heat-affected zone while almost no influence on the axial residual stress component was recorded.

Background/Objectives: Hungry bone syndrome (HBS) is a frequent and potentially life-threatening complication following parathyroidectomy (PTX) for secondary hyperparathyroidism (SHPT) in dialysis patients, yet existing prediction tools offer limited discriminative accuracy. This study aimed to develop and internally validate an interpretable machine learning (ML) framework for preoperative HBS prediction and to derive a pragmatic bedside risk score from ML-derived feature importance. Methods: Ninety end-stage renal disease patients who underwent PTX for drug-refractory SHPT at a single center (2019–2023) were analyzed. Eight supervised ML classifiers were trained on 24 preoperative features (19 raw variables plus 5 engineered features) and evaluated under 5-fold stratified cross-validation repeated 10 times. SHapley Additive exPlanations (SHAP) analysis was applied for model interpretability, and a composite bedside risk score was constructed from SHAP-derived feature rankings. Results: HBS occurred in 41 patients (45.6%). Random forest achieved the numerically highest discrimination among multi-feature models (AUC = 0.933 ± 0.065), outperforming previously published models, though univariate alkaline phosphatase (ALP) alone achieved a comparable cross-validated AUC of 0.958. ALP overwhelmingly dominated all predictors (mean |SHAP| = 3.37, exceeding the next-ranked feature by approximately 6.5-fold). Partial dependence analysis revealed a sigmoid-shaped ALP–HBS relationship with a critical inflection zone between 250–350 U/L, and SHAP dependence plots demonstrated that total parathyroidectomy amplifies ALP-mediated risk. A SHAP-guided composite bedside risk score (range 0–9) achieved an AUC of 0.883, with observed HBS rates rising monotonically from 0% (score 0) to 100% (score ≥ 6). Decision-curve analysis showed that univariate ALP and the multi-feature pipeline yielded comparable net benefit, with ALP preferable in the high-sensitivity regime and the multi-feature model preferable at high-specificity thresholds; net reclassification improvement was negative for the multi-feature model vs. univariate ALP, supporting the framework’s role as an interpretive rather than discriminative advance. Conclusions: An interpretable ML framework substantially improves HBS prediction over conventional models, confirms ALP as the overwhelmingly dominant predictor through a nonlinear dose–response relationship, and yields a clinically interpretable bedside risk score that, pending external validation, may support preoperative risk stratification.

Microplastics (MPs) pollution constitutes a critically escalating global environmental challenge. Understanding dissolved organic matter (DOM)-MPs interactions and their transport behavior in soil and aquatic systems is of fundamental significance. However, contradictory observations regarding the impact of DOM on the fate of MPs exist in the literature, hindering our understanding of their risk and ecological impacts. To date, quantitative evidence explaining how DOM self-assembly influences the transport kinetics of MPs or other emerging particulate contaminants has not been explored. Here, we employed excitation-emission matrix spectroscopy, colloidal atomic force microscopy, and microfluidic systems to systematically elucidate DOM-mediated mechanisms controlling the fate of pristine and aged MPs from molecular, nano, and interfacial scales in a coherent manner. Direct evidence demonstrated that interactions among DOM components mediated the process of self-assembly on MPs and hematite surface, resulting in nonmonotonic deposition behavior in response to an increase in DOM concentration. The pristine MPs prefer to adsorb hydrophobic DOM fractions via nonspecific interactions, whereas aged MPs undergo a triphasic DOM self-assembly process due to the variation in DOM concentration and composition through specific interactions. Consequently, their deposition fluxes on hematite vary accordingly: pristine MPs flux decreased to (49.8 ± 2.9) × 10-4 μm/min then increased to (64.0 ± 4.5) × 10-4 μm/min, whereas aged MP flux decreased to (12.4 ± 1.8) × 10-4 μm/min, subsequently increased to (22.1 ± 0.8) × 10-4 μm/min, and finally declined to (4.0 ± 2.0) × 10-4 μm/min. Critical DOM concentrations serving as the "inflection point" of deposition fluxes for both pristine MPs and aged MPs were identified. Overall, this study establishes a novel framework for investigating the deposition mechanisms of MPs and other particulate pollutants, highlighting the critical role of DOM self-assembly in regulating the fate of contaminants in DOM-rich environments. The observed molecular fractionation of DOM, dictated by both concentration and composition, determines its interactions with minerals, thereby regulating the subsequent stabilization and biogeochemical cycling of carbon within the earth's critical zone.

Coastal regions in Indonesia are currently facing unprecedented risks from the convergence of global climatic shifts and localized geological instability. This study investigates the intensifying vulnerability of the Jakarta-Bekasi coastal corridor, highlighting it as a critical zone within the broader context of regional climate adaptation. The objective is to evaluate the synergistic impact of eustatic sea-level rise and aggressive land subsidence on permanent inundation projections through 2030. Utilizing a quantitative geospatial design, the research integrates satellite altimetry from the Sentinel-6 mission with terrestrial geodetic data from 12 Continuous Operating Reference Stations (CORS) across a 12,500-hectare study area. Key variables include vertical land motion rates and sea surface height anomalies, processed through high-resolution Digital Elevation Models (DEMNAS). Results indicate that localized land subsidence, peaking at 11.2 cm per year, is the primary driver of flood risk, rendering Relative Sea Level Rise () significantly more destructive than global eustatic averages. Statistical analysis confirms that subsidence accounts for 82% of the variance in coastal inundation expansion, with critical hotspots in the Penjaringan and Muara Gembong sectors. These findings imply that current coastal defense structures are nearing functional failure due to the rapid erosion of operational freeboards. Consequently, the study concludes that regional resilience necessitates a shift from static engineering to adaptive water management and the implementation of Nature-based Solutions. Future research should prioritize AI-driven predictive modeling and volumetric building load analysis to enhance long-term mitigation strategies.

Underground karst is a sensitive component of the Earth's Critical Zone (ECZ), capable of preserving changes in its dynamics driven by both natural and anthropogenic forces. In this study, we examine the Holocene sedimentary archive preserved in Tana della Mussina Cave (TdMC) in the northern Apennines of Italy. This archive includes clastic and chemical (speleothem) sediments, as well as archaeological deposits linked to human occupation of the site since the Copper Age. Our reconstruction indicates that sedimentation in the cave responded to changes in the hydrology of the karst system, alternating between phases of clastic deposition and periods of sedimentary hiatus, along with a documented phase of speleothem precipitation. Clastic sedimentation occurred particularly after the Greenlandian/Northgrippian boundary and again at the onset of the Meghalayan phase of the Holocene, likely in response to increased water availability, which led to the accumulation of fluvial sediments transported through the TdMC catchment. In contrast, speleothem deposition took place later, between 3800 and 2200 years BP. From around 5500 years BP, clastic sedimentation is marked by a significant accumulation of charcoal and lumps of heated sediment/soil. We interpret this evidence because of human activity, specifically extensive deforestation, which has been archaeologically documented in the region since the Copper Age. The slash-and-burn technique, used to clear land for pasture or agriculture, increased soil erosion rates, leading to a greater influx of sediments into the karst system, including charcoal and remnants of heated soils. This case study provides an example of early human land use change impacting surface processes and influencing the dynamics of the ECZ. • We investigate the clastic and anthropogenic deposits and speleothems in the Tana della Mussina Cave. • Clastic sediments developed following increased soil erosion in the karst catchment. • Soil erosion was intermittently triggered by human impact since the Early Holocene. • The slash and burn practice caused surface instability and increased sediment flux into the karst system. • This study confirms an early human impact on Earth's Critical Zone processes.