Search Results (34)

Microbial synthesis of selenium nanoparticles (SeNPs) offers a sustainable alternative to chemical routes, but the genetic basis of selenium handling in Bacillus remains poorly defined, which limits rational strain selection. Here, SeNP production, physicochemical characterization, and closed-genome sequencing are combined for Bacillus licheniformis BLN313. Selenite reduction peaked at 500 µg/mL Na₂SeO₃ (88.8% conversion; 444 ± 27 µg/mL Se⁰); at higher concentrations, conversion efficiency and viability diverged, indicating that tolerance and reductive capacity are distinct traits. Purified SeNPs were spherical and partially crystalline trigonal Se⁰ (TEM 190 ± 52 nm; DLS 166 nm, PDI 0.03; zeta potential −20.8 mV), carrying a proteinaceous capping layer confirmed by XPS, EDS, and FTIR and shown by LC-MS to be enriched in cell wall-derived metabolites. The particles were bactericidal against Micrococcus luteus (MIC 62.5 µg/mL) and Klebsiella pneumoniae (MIC 250 µg/mL) and reduced MCF-7 viability (IC50 2.7 µg/mL) while sparing MCF-10A cells. The 4.11 Mb genome (46.3% GC; ANI 99.7%, dDDH 97.8%) encodes SulP and Pit transporters, multiple trxB copies, and sulfur-metabolism and oxidative-stress genes, defining a candidate gene set for selenium uptake, reduction and detoxification. BLN313 thus provides a genetically defined platform for SeNP production in biomedical and environmental applications. Full article

Open-pit coal mining in arid and desert regions causes extensive and persistent surface disturbance, yet long-term monitoring of disturbance and backfilling processes remains challenging. Existing time-series change detection approaches can identify spectral changes but provide limited information on mining disturbance types and their evolution pathways. To address this issue, an automated surface disturbance detection method (Auto-SD) was developed for open-pit coal mines in arid and desert environments. This method integrates disturbance-type identification and temporal information extraction using the tasseled cap brightness (TCB) component to characterize changes associated with surface material exposure and accumulation. Using Landsat imagery from 1990 to 2023, Auto-SD was applied to 89 open-pit coal mines in China’s arid and desert regions, achieving an overall classification accuracy of 0.84. The cumulative disturbed area reached 423.10 km², while the internal dumping area reached 94.25 km², indicating limited backfilling recovery. Disturbance intensified after 2006, whereas backfilling lagged behind, forming a trajectory of rapid expansion, delayed recovery, and gradual stabilization. Spatially, mining areas exhibited a progressive transition from external dumping to internal dumping and backfilling. Furthermore, cumulative pit area generally followed an S-shaped growth pattern with mining duration. These findings provide new insights into long-term mining landscape evolution and support ecological restoration assessment and sustainable resource management in arid mining regions. Full article

This study addresses the safety and efficiency challenges of manual inspection in complex open-pit mining environments, where terrain steepness, limited coverage, and personnel exposure to hazards render conventional methods inadequate. We propose an integrated UAV inspection framework that combines 3D environmental modeling with a hierarchical optimization paradigm. The framework operates in three sequential stages. First, a high-fidelity 3D terrain model is constructed from point cloud data via skeletal feature extraction, which reduces computational complexity while preserving topographic structure. Second, an upper-layer Traveling Salesman Problem (TSP) solver determines the optimal inspection sequence across mandatory points (loading sites, dump sites, and crushing stations). Third, a lower-layer Chaotic Adaptive Population-based Grey Wolf Optimizer (CAP-GWO) refines the 3D path between consecutive TSP-ordered points, augmented by B-spline smoothing to ensure kinematic feasibility. Key inputs include: (i) raw LiDAR point cloud data of the mining site, (ii) facility coordinates and operational constraints (safety margins, maximum pitch angle, minimum turn radius), and (iii) UAV kinematic parameters. Outputs comprise a smooth, collision-free 3D trajectory with verified constraint satisfaction. Comparative experiments against eight metaheuristic algorithms (PSO, GA, ACO, BA, COA, GWO, SRA, SFOA) demonstrate that the proposed method reduces total path length by 15–20% on synthetic benchmark scenarios while maintaining zero constraint violations. Statistical validation via the Sign Test confirms the significance of these improvements (p < 0.05) across repeated independent trials. The framework is further validated on measured airborne LiDAR data of the Bingham Canyon open-pit copper mine (Utah, USA; USGS 3D Elevation Program), one of the largest operating open-pit mines in the world: on this real terrain, CAP-GWO achieves the best performance among the GWO-family algorithms, with a statistically significant 12.5% improvement over SRA (Wilcoxon p < 0.001) and 24% lower variance than the standard GWO, and all 210 experimental runs produce collision-free trajectories. Notably, the proposed hierarchical optimization framework achieves structural symmetry between the upper-layer sequencing task and the lower-layer path refinement task. This symmetric decomposition significantly reduces computational complexity while preserving solution quality, aligning with the principles of symmetry in engineering optimization. The framework offers a practical solution for autonomous, adaptive inspection scheduling in dynamic mining environments. Full article

Continuous spatial reconstruction in highly fragmented landscapes remains a persistent challenge in remote sensing and geographic information systems. Standardized products such as MODIS Net Primary Productivity (NPP) provide temporally consistent ecological baselines, but their moderate spatial resolution can obscure abrupt transitions in disturbed environments. This study develops a biophysical index-guided 1 × 1 Convolutional Neural Network (CNN) framework for NPP reconstruction over a mega-scale open-pit mining landscape. The framework uses five Landsat-derived biophysical tensors—Vegetation Moisture Stress Index (VMSI), Anti-Vegetation Environment Index (AVEI), Soil Adjusted Vegetation Environment Index (SAVEI), AAI-VHI, and Tasseled Cap Wetness (WET)—as point-wise predictors aligned to the MODIS NPP baseline grid. By restricting convolutional kernels to 1 × 1, the model performs nonlinear channel-wise mapping without incorporating neighboring grid cells, thereby reducing boundary mixing that can occur in conventional multi-pixel CNNs. Benchmark comparisons with Random Forest and a standard 3 × 3 CNN showed that the 3 × 3 CNN achieved slightly higher global accuracy, whereas the 1 × 1 CNN provided stronger gradient correspondence and lower full-domain spatial error in the 2020 spatial fidelity assessment. The results indicate that point-wise convolution guided by physically interpretable indices provides a conservative and interpretable option for standardized ecological reconstruction at the MODIS baseline grid scale. Full article

Background and Objectives: Sessile serrated lesions (SSLs) are increasingly recognized as relevant precursors in alternative pathways of colorectal carcinogenesis, yet their endoscopic recognition remains challenging. Materials and Methods: We conducted a systematic review of studies reporting endoscopic and patient-related features associated with SSLs. PubMed/MEDLINE was searched for studies published between 2003 and November 2025. Eleven studies including 13,453 participants were identified. Results: Frequently reported endoscopic hallmarks included proximal colon location, larger lesion size, flat or slightly elevated morphology, indistinct borders, mucous cap, cloud-like surface, and pit-pattern features consistent with Kudo/Fujii types III–IV. Considerable heterogeneity in definitions and analytical reporting was observed. Conclusions: Although several features may raise suspicion for SSLs, standardized evidence remains limited, supporting a cautious and comprehensive approach to polyp assessment. Full article

This study investigates the influence of Ag addition on the microstructure, mechanical behavior, corrosion resistance, and antibacterial performance of Mg-Zn-Ca-Ag alloys and their micro-arc oxidation (MAO) coatings. Four casting alloys containing 0.2, 0.4, 0,6 and 0.8 wt.% Ag were fabricated and characterized by SEM, XRD, and TEM. The microstructure consisted mainly of α-Mg, Mg₂Ca, Mg₇Zn₃, and Mg₆Ca₂Zn₃ phases, and the elastic modulus (~25.8 GPa) was comparable to that of human bone. MAO coatings produced in a bio-functional electrolyte exhibited pit-like morphologies due to Ag-induced melt fluidity and self-sealing effects. The coatings were composed primarily of MgO, Mg₂SiO₄, Ca₃(PO₄)₂, CaCO₃, and Ag₂O, with the ZQ 0.8-MAO sample showing the highest Ca/P ratio (1.75), indicative of superior bioactivity. Electrochemical impedance spectroscopy revealed optimal corrosion resistance (2.56 × 10⁴ Ω·cm²), while antibacterial efficiency exceeded 96%. Overall, Ag alloying enhanced both the bulk and surface properties of Mg-Zn-Ca alloys, yielding robust, corrosion-resistant, and antibacterial coatings with excellent biocompatibility-highlighting their potential for biodegradable orthopedic implant applications. Full article

A sedimentary profile consisting of blown sand capped by a sand-loam bedded interval was analysed in the Svätuše sand pit in the East Slovak Lowland. Stratigraphically, blown sands from this lowland have so far only been indirectly classified into the Weichselian glacial, mainly into its middle and upper stages. The age classification presented in this study results from the optically stimulated luminescence dating method. It identifies the blown sand from the Svätuše as originating during the Early Glacial and Early Pleniglacial phases of the Weichselian glacial (MIS 4–5d). At the end of the Early Glacial phase of the Weichselian glacial, palaeoenvironmental conditions changed. The deposition of blown sand became episodic rather than continuous. As a result, the analysed sedimentary record is composed of a sand-loam interbedded interval in the uppermost part. Full article

Due to high sedimentation rate up to ~1 m/year, mud-capped dredge pits (MCDP) are often considered natural laboratories for studying sedimentary processes, slope stability and the impacts of dredging activities on marine environments. Although many studies have been performed on the Louisiana shelf, there is a lack of high spatial resolution research covering the eastern, central and western Louisiana shelf to comprehensively investigate sediment infilling. Eighteen vibracores were collected from the Peveto Channel dredge pit (PC), Raccoon Island dredge pit (RI) and Sandy Point dredge pit (SP), and more than 1300 samples were analyzed to study the spatial variation in surficial sediment using statistical analyses. Our results indicate that the inner Louisiana continental shelf is silt-dominated, and there was no consistent grain size variation when comparing the sediment within the pits with that outside the pits. Skewness emerged as a prominent factor in the RI and SP, while standard deviation was the most influential in the PC. Our analysis shows also that two principal components are confirmed and account for more than 95% of the total grain size variance. Full article

Base Mine Lake (BML) is the first full-scale demonstration of water-capped tailing technology in a pit lake to reclaim lands impacted by surface mining in the Alberta Oil Sands Region (AOSR). Biogeochemical cycling and/or exchange near the fluid water interface (FWI) of the organic-rich fluid fine tailings (FFT) can hinder the reclamation process. To monitor this activity, sedimentary depth profiles were collected from three platforms (P1 to P3) at BML. Seventy-four chromatographically well-resolved petroleum hydrocarbon (PHC) isomers were quantified at each depth interval using comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GC × GC/TOFMS). The range of total concentrations of all isomers examined across the FFT was the highest at P1 (range = 3.6 × 10⁰–5.5 × 10³ ng/g TOC), second highest at P2 (range = 3.8 × 10⁰–1.9 × 10³ ng/g TOC), and lowest at P3 (range = 5.6 × 10⁰–7.1 × 10² ng/g TOC). The elevated levels of the same isomers across platforms suggest a consistent source fingerprint. While the source fingerprint was mostly consistent across the platforms and depths, Principal Component Analysis (PCA) identified small differences between geospatial locations caused by variations in specific isomer concentrations. Hierarchical Clustering Analysis (HCA) identified the isomers responsible for the PCA separation, showing that the concentrations of low-molecular-weight n-alkanes (C11–C13) and drimane varied compared to the heavier PHCs with depth. These alkanes are the most biodegradable of the compounds identified in this study, and their variations may reflect biogeochemical cycling within the FFT. Combining these statistical tools provided deeper insight into how isomer concentrations vary with depth, helping to identify possible influences like changing inputs, biogeochemical cycling, and species exchange with the water column. Full article

Water-capped tailings technology (WCTT) is a strategy where oil sand tailings are sequestered within a mined-out pit and overlayed with a layer of water in order to sequester tailings with the aim that the resulting pit lake will support aquatic plants and organisms over time. The Base Mine Lake Demonstration (BML) is the first full-scale demonstration of a pit lake in the Athabasca Oil Sands Region (AOSR). In the BML, the release of methane from the fluid tailings influences several key processes, including the flux of greenhouse gases, microbial oxygen consumption in the water column, and ebullition-facilitated transport of organics from the fluid tailings to the lake surface. It is hypothesized that the residual low molecular weight hydrocarbons (LMWHCs) derived from diluent naphtha used during bitumen extraction processes are the carbon sources fueling ongoing microbial methanogenesis within the BML. The aims of this study were to identify the LMWHCs in the BML fluid tailings, to elucidate their sources, and to assess the extent of biogeochemical cycling affecting them. A headspace GC/MS analysis identified 84, 44, and 56 LMWHCs (C4–C10) present in naphtha, unprocessed bitumen ore, and fluid tailings, respectively. Equilibrium mass balance assessment indicated that the vast majority (>95%) of LMWHCs were absorbed within residual bitumen rather than dissolving into tailings pore water. Such absorbed compounds would not be readily available to in situ microbial communities but would represent a long-term source for methanogenesis. Chromatographic analysis revealed that most biodegradable compounds (n-alkanes and BTEX) were present in the naphtha but not in fluid tailings or bitumen ore, implying they are sourced from the naphtha and have been preferentially biodegraded after being deposited. Among the LMWHCs observed in bitumen ore, naphtha, and fluid tailings, C2-cyclohexanes had the highest relative abundance in tailings samples, implying their relatively high recalcitrance to in situ biodegradation. Full article

To mitigate the impact of foundation pit construction on adjacent existing structures, grouting reinforcement techniques are often employed to enhance the deformation strength of the soil. This study focuses on the expansion project of the Dayun Comprehensive Hub in Shenzhen, conducting full-scale numerical simulations of the excavation of deep foundation pits adjacent to existing elevated railways and examining the effects of different grouting reinforcement schemes. The results indicate that the single-row and double-row grouting schemes increased the bearing capacity of the foundation piles by 23.7% and 31.9%, respectively, significantly enhancing the structural bearing performance. After reinforcement, the maximum deformation position of the elevated bridge foundation piles shifted upward, and the settlement distribution of the cap beam became more concentrated, indicating that grouting reinforcement effectively controlled the ground settlement and the deformation of the foundation piles. Furthermore, compared to controlling the deformation of the retaining structures, grouting reinforcement was more effective in controlling ground settlement and pile deformation, highlighting its advantages in complex environments. Although the double-row grouting scheme demonstrated superior technical performance, the single-row scheme remains the preferred option considering reinforcement efficiency and economic factors. Full article

This study investigated the combined effects of adding niobium–fluoride (NbF₅) nanoparticles to a pit-and-fissure sealant. One resin sealant was reinforced with varying amounts of nanoparticles (0.3, 0.6, and 0.9 wt%). The surface hardness (SH), energy-dispersive X-ray spectroscopy (EDX), surface roughness (Ra), color change (ΔE), and mineral deposition were assessed. Bovine enamel blocks were subjected to demineralization and pH-cycling for SH. The elemental composition and Ca/P ratio were evaluated using EDX, while the mineral deposition was measured using Fourier transform infrared spectroscopy (FTIR). Data were analyzed using ANOVA and Tukey’s test for the SH and EDX, ΔE, and Kruskal–Wallis for the Ra. The NbF₅ modification increased the SH, with the 0.9 wt% sealant exhibiting higher SH values, and the 0.3 wt% one exhibiting significant differences compared to the control and the 0.9 wt% (p = 0.00) samples, even after pH-cycling. For the EDX analysis, the 0.3 and 0.6 wt% samples exhibited higher Ca/P ratios, with the 0.3% one showing evidence of P-O crystal formation. There was no significant difference in the Ra (p = 0.458), and the 0.6 and 0.9 wt% ones showed lower ΔE values compared to the control. The 0.3 wt% NbF₅ demonstrated improved overall properties, making these results particularly promising for preventing tooth decay, reducing demineralization through increased ions release and promoting remineralization in posterior teeth. Full article

Small-scale open-pit, non-artisanal mining of low-value ores is an understudied practice despite its widespread occurrence and potential impact on freshwater resources due to mining-induced land-use/cover changes (LUCCs). This research investigates the long-term impacts of andesite mining in Pasuruan, Indonesia, on the Umbulan Spring’s water discharge within its watershed. System Dynamics (SD) modeling captures the systemic and systematic impact of mining-induced LUCCs on discharge volumes and groundwater recharge. Agricultural and reservoir-based land reclamation scenarios then reveal post-mining temporal dynamics. The no-mining scenario sees the spring’s discharge consistently decrease until an inflection point in 2032. With mining expansion, reductions accelerate by ~1.44 million tons over two decades, or 65.31 thousand tons annually. LUCCs also decrease groundwater recharge by ~2.48 million tons via increased surface runoff. Proposed post-mining land interventions over reclaimed mining areas influence water volumes differently. Reservoirs on reclaimed land lead to ~822.14 million extra tons of discharge, 2.75 times higher than the agricultural scenario. Moreover, reservoirs can restore original recharge levels by 2039, while agriculture only reduces the mining impact by 28.64% on average. These findings reveal that small-scale non-artisanal andesite mining can disrupt regional hydrology despite modest operating scales. Thus, evidence-based guidelines are needed for permitting such mines based on environmental risk and site water budgets. Policy options include discharge or aquifer recharge caps tailored to small-scale andesite mines. The varied outputs of rehabilitation scenarios also highlight evaluating combined land and water management interventions. With agriculture alone proving insufficient, optimized mixes of revegetation and water harvesting require further exploration. Full article

In view of the safety of the construction of the long foundation pit of the new upper span to the existing subway under urban complex environment conditions, combined with the construction of the intersection section of the first line of the existing subway across the north–south Expressway in Shenyang, the mechanical properties during construction were studied by means of numerical simulation and on-site monitoring. The results showed that the general deformation characteristic of the existing metro tunnel was “uplift first, then restrain”. The local deformation characteristic was an unloading rebound in the cross region, and a compression deformation occurs outside the cross region. The index could be controlled in the range of the control value of the existing line protection by adopting the measures consisting of an uplift pile + capping beam balance, reinforcing the surrounding soil, the excavation of the foundation pit in sections, and the comprehensive construction. Full article

Increased food production and consumption patterns have resulted in higher urban food phosphorus footprints, leading to a series of resource and environmental problems worldwide. We quantified the food phosphorus footprint of the African city of Kisumu using substance flow analysis. Our aim was to develop Kisumu’s sustainable phosphorus management framework so that the city would reduce phosphorus losses into the food system. Our results show that in the year 2023, the import and export of food phosphorus in the Kisumu food system was 2730.26 ± 2.7% t P yr⁻¹ and 3297.05 ± 2.4% t P yr⁻¹, respectively. There was −566.79 ± −18% t P yr⁻¹ food phosphorus deficit in the Kisumu food system. Crop planting subsystem runoff/leaching/erosion loss, household consumption subsystem waste loss, and pit latrine subsystem blackwater loss are the major pathways of phosphorus losses into the environment and the main contributors to the food phosphorus footprint in the city. The 2030 scenario analysis shows that implementing a comprehensive scenario scheme throughout the entire lifecycle process from phosphorus input to waste disposal is the best choice for reducing phosphorus losses and suppressing the growth of food phosphorus footprint in the future. Our study shows that the food phosphorus footprint in the Kisumu food system was 0.67 kg P cap⁻¹yr⁻¹ in 2023, which is still at a low level but may enter a continuous upward trend with the improvement of socio-economic development of the city. In our framework, we have proposed a few essential measures that include urine separation, installation of septic tank, adjustment of dietary structure, flexible layout of sanitary disposal facilities, and separation of organic waste streams to reduce food phosphorus footprints in Kisumu. Given the similarity of cities along the shores of Lake Victoria, our calculation methods and management strategies can be applied to other cities in the region. Full article