Search Results (5,929)

Forest fires cause societal damage, including injuries, burns, and the development and exacerbation of cardiorespiratory diseases. One of the damaging factors of forest fires is carbonaceous particles heated up to high temperatures. These particles are carried from the forest fire front and can interact with human tissue. Three scenarios for the interaction of a heated carbonaceous particle with human tissue are considered. The first scenario involves particle impact on the skin. The second scenario involves particle impact on the nasopharyngeal mucosa. The third scenario involves the impact on the tissues of the upper airways. A two-dimensional mathematical statement is considered in the “carbonaceous particle–human tissue” system. Mathematically, the heat transfer process is described by non-stationary parabolic partial differential equations with corresponding initial and boundary conditions. The problem is solved using locally one-dimensional and finite-difference methods. Difference analogs of the differential equations are solved using the marching method. Temperature distributions for particles of varying sizes and initial heat contents were obtained. The software realization was implemented using the high-level Object Pascal programming language in the RAD Studio environment. Conclusions were drawn regarding the potential practical applications of the developed software in healthcare and environmental protection. Full article

The fractal characteristics of coal pore–fracture networks and their evolution under compression are essential for predicting rock mass failure and fluid transport. This study combines micro-CT scanning with fractal theory and seepage mechanics to investigate the structural evolution of coal under uniaxial compression and its impact on fluid transport. CT scans were performed at four characteristic stages (initial, elastic, plastic, and failure) to reconstruct three-dimensional fracture networks. Quantitative analysis reveals that fracture porosity increases sequentially from 0.44% to 5.01%, with the failure stage reaching 11.4 times the initial value. Fracture length and aperture distributions follow power-law scaling, and their fractal dimensions exhibit distinct evolution patterns: length dimension increases from 2.43 to a peak of 2.56 in the plastic stage and then drops to 2.47 at failure, while aperture dimension decreases from 2.29 to a trough of 2.12 before rebounding to 2.26. These patterns reflect a dynamic adjustment of network complexity, transitioning from primary fractures to micro-fracture dominance and finally to main fracture coalescence. Based on the Knudsen number, three diffusion regimes of Fick, transition and Knudsen are identified. A fractal permeability model is developed by idealizing the pore space as tortuous capillaries, showing that permeability scales with the fourth power of the maximum pore diameter and is positively influenced by the fractal dimension and the number of large pores. Furthermore, a coupled seepage–stress model is derived, incorporating pressure transmission, shear transmission, and crack opening coefficients. The damage variable is expressed as a function of stress level and fractal dimension. These findings provide theoretical support for predicting gas transport and failure behavior in coal under coupled hydro-mechanical conditions. Full article

To investigate the dynamic impact performance of carbon fiber reinforced polymer (CFRP)-confined recycled concrete, this study designed four series comprising 80 specimens with parameters including strain rate, recycled coarse aggregate replacement ratio, and number of CFRP confinement layers. Split Hopkinson Pressure Bar (SHPB) impact tests were conducted to analyze the dynamic failure mode, stress–strain responses under dynamic loading, and variation in compressive strength of the CFRP-confined concrete specimens. Additionally, a modified Weibull statistical model and fractal theory were employed to analyze the dispersion characteristics of dynamic compressive strength. The results show that the dynamic compressive strength exhibits clear strain-rate sensitivity. The presence of CFRP confinement does not alter the fundamental shape of the stress–strain curves under different strain rates. The proposed modified Weibull statistical model accurately predicts the distribution of dynamic compressive strength at varying strain rates, with an average prediction error of 3.4% and a maximum error of 5.3%. Fractal dimension can quantitatively characterize the evolution trend and degree of crack-induced damage. Within the strain rate range of 52.85–138.42 s⁻¹, the fractal dimension of unconfined ordinary concrete specimens increases from 1.647 to 2.138; for unconfined recycled concrete, it increases from 1.612 to 2.158. The fractal dimension for CFRP-confined ordinary concrete specimens increases from 1.524 to 1.938, and for CFRP-confined recycled concrete specimens, from 1.503 to 2.019. The fractal dimension increases with the increase of strain rate, reflecting a typical strain rate effect. Full article

Polycyclic aromatic hydrocarbons (PAHs) are widespread, persistent pollutants that can be sequestered within human adipose tissue due to their lipophilic nature. While this accumulation poses toxicological risks depending on dose and individual susceptibility, the specific morphological impact of chronic PAH storage on tissue architecture remains poorly defined. Here, we performed a histopathological and morphometric analysis on human subcutaneous adipose tissue samples characterized by high pyrene levels. We evaluated tissue organization, collagen distribution, the presence of inflammatory, neural, and vascular alterations and adipocyte morphometry to assess the structural response to PAH sequestration. Despite high pyrene concentrations, PAH-positive tissues maintained preserved overall architecture with normal collagen distribution, absence of lymphocytic infiltration, low macrophages, unaltered nerve fiber patterns, without evidence of vascular remodeling. Morphometry revealed smaller adipocyte area in PAH-positive samples, although not statistically significant. Our experimental data indicate that high PAH accumulation does not necessarily induce subcutaneous adipose tissue remodeling, suggesting that biochemical or metabolic alterations might occur even in the absence of evident histological changes. Further studies, with a broadened cohort, are needed to define the threshold at which PAHs’ presence translates into permanent tissue damage. Full article

It is an accepted paradigm in the already matured industry of Quantum Key Distribution (QKD) implementations that when the quantum channel is attacked or unresponsive, the system reverts to classical security. Thus, in times of crises, when the quantum system is severely damaged, the saving resort is considered to be the classical solution. This paper explores the opposite approach. In the case of disaster, when parts of the classical part of the key distribution system are broken, are there any possible crisis management options to give some limited functionality? The result of this research shows that if the classical channel fails, the quantum channel can still produce and distribute keys. The experimental results of the contingency QKD show that, using positive operator-valued measurements (POVMs), keys can still be produced and shared. The scheme described in this paper uses the quantum channel only to distribute imperfect keys. Any one distributed key has a theoretical overlap of approximately $75\%$ between Alice’s key and Bob’s key, respectively. The experimental POVM circuit is implemented with two different Naimark dilation approximations: one using $R_z$ gates and the other using $R_y$ gates. The practical implementation results are close to the theoretical analysis. As the keys have a partial overlap, the encryption/ decryption algorithm also needs to adjust to this reality. The encryption/decryption algorithm used in the experiments is a repetition algorithm that is simple but shows the resilience of the scheme. Ultimately, the classical channel is not used during the contingency QKD at all, while the quantum channel is assumed trusted under a restricted adversary model in which Eve is limited to individual attacks. Under this model, partial secrecy is retained for all non-zero channel error rates below a pre-agreed threshold. Full article

The mechanical properties and real-time damage evolution of sustainable concrete (SC) containing 100% recycled concrete aggregate (RCA) under the combined action of hybrid steel and polyolefin fibers were studied. Inspired by solving the massive effects on the environment from construction waste, as well as to improve the lower mechanical performance of lower-grade RCA, the effect of combining high-stiffness hooked-end steel fibers and flexible macro-polyolefin fibers within RCA was investigated. Six different mix designs were considered: plain, single-fiber (100% steel and 100% polyolefin) and three hybrid composites with varying fractions of the steel/polyolefin fibers (25/75, 50/50, and 75/25). Compressive, tensile and flexural strengths were determined by mechanical testing. During compressive testing, the damage evolution was monitored using low-cost acoustic emission (AE) as a non-destructive technique. Cumulative hits analysis, amplitude distributions, and the statistical b-value parameter were used for damage characterization. The results show that steel fiber significantly increased compressive strength (an increase of up to 13.8%), and the 50/50 hybrid mix showed a high synergistic effect, yielding the highest tensile (4.86 MPa) and flexural (25.54 MPa) strengths. AE analysis identified different damage fingerprints: Based on amplitude analysis, steel-fiber composites exhibited high-amplitude events (which may be attributable to fiber pull-out); polyolefin-fiber composites generated medium-amplitude events (may have resulted from distributed microcracking); and hybrid mixes displayed a mixed amplitude distribution. The b-value analysis provided insight into progressive damage and revealed that the hybrid fibers induce stable, diffuse damage that prevents the brittle failure of plain recycled aggregate concrete (RAC). The results show that hybrid fiber reinforcement can be a reliable approach to enhance the mechanical performance and crack resistance of RAC. Furthermore, low-cost acoustic emission (AE) serves as an effective non-destructive method for monitoring damage progression within the material. Full article

Background/Objectives: DNA-targeting small molecules that induce replication stress represent a promising strategy in anticancer drug development. 1,8-Naphthalimide (NI) derivatives are well-established DNA-intercalating agents, and heterocyclic annulation offers a rational approach to enhancing their potency and tumor selectivity. Here, we report the synthesis and biological evaluation of a novel series of benzofuran-containing naphthalimide derivatives, with particular focus on the lead dinitro-substituted compound 5d. Methods: Cytotoxic activity was assessed using the MTT assay in A549 (p53 wild-type), H1299 (p53-null), and MRC-5 cells. Long-term antiproliferative effects were evaluated by clonogenic survival assay. Cell cycle distribution was analyzed by propidium iodide staining and flow cytometry. Replication stress and DNA damage were quantified by EdU incorporation and γH2AX immunofluorescence, respectively. Apoptosis was assessed by Annexin V/PI staining and caspase-3/7 activation assay. p53 nuclear accumulation and autophagy induction were evaluated by immunofluorescence and Western blot, using LC3 as an autophagic marker. Results: All compounds exhibited cytotoxic activity in the nanomolar range, with 5d emerging as the most potent and selective. Clonogenic survival was significantly reduced, indicating durable suppression of proliferative capacity. Treatment with 5d induced G₁ arrest in A549 cells and the accumulation of H1299 cells in G₂/M, consistent with p53-dependent and p53-independent checkpoint activation, respectively. EdU incorporation was markedly reduced, while γH2AX intensity increased, collectively supporting a replication stress-driven mechanism of DNA damage. Apoptosis was confirmed by increased Annexin V-positive populations and caspase-3/7 activation. LC3 puncta formation and LC3-I/LC3-II conversion were increased, indicating LC3 processing and autophagosome accumulation consistent with the activation of autophagy-related processes. Conclusions: 5d induces a cellular phenotype consistent with replication stress, including reduced EdU incorporation, γH2AX accumulation, cell cycle arrest, and apoptotic cell death in a p53 status-dependent manner. These findings establish benzofuran-annulated naphthalimides as a promising scaffold for the development of anticancer agents that exploit replication stress vulnerabilities in tumor cells. Full article

Preterm infants, especially extremely preterm infants under 28 weeks of gestation, face high mortality rates due to respiratory distress resulting from pulmonary immaturity. Conventional mechanical ventilation and extracorporeal membrane oxygenation (ECMO) therapy inevitably cause irreversible lung injury or severe complications, respectively. Here, we developed a microfluidic oxygenator (MO) mimicking the human alveolar-capillary barrier to provide respiratory support for preterm infants. These structures promoted uniform flow distribution, reduced high-shear stress and flow stagnation, and improved gas exchange efficiency. In vitro experiments demonstrated that a single-layer MO raised blood oxygen saturation from 64.7% to 96.5% at 8 mL/min, with a corrected vol% oxygen transfer of 5.24% (52.4 mL O₂/L blood). Hemolysis and coagulation measurements after a 6 h circulation confirmed good hemocompatibility, with most blood damage attributable to the pump. An eight-layer stacked MO was configured with a total priming volume of approximately 5.6 mL and a pressure drop of 25–35 mmHg at 24–40 mL/min, indicating its potential in pumpless extracorporeal circulation for preterm neonates. This MO holds promise for providing minimally invasive and customizable respiratory support in an artificial uterus system. Full article

Aquatic organisms are exposed to multiple stressors, including microplastic pollution and rising temperatures. Bioplastics like Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) are considered sustainable alternatives to conventional plastics, although their biological effects remain poorly understood. This study evaluated the effects of PHBV microplastics on Artemia franciscana under different temperature and exposure conditions. Organisms were exposed to 25 and 100 mg·L⁻¹ PHBV for 7, 14, and 21 days at 25 °C and for 14 days at 29 °C. Growth, development, antioxidant enzyme (CAT, GST) and esterase activities (ChE, CbE), lipid peroxidation (LPO), gut histology, fatty acid profiles and polymer particle length distributions were assessed. Growth and development increased with PHBV concentration, exposure time, and temperature. Enzymatic activities and LPO were significantly affected by these factors, although no evidence of oxidative damage was detected. Marked gut lesions were observed at 100 mg·L⁻¹ PHBV at 29 °C after 14 days. Fatty acid profiles were mainly influenced by time and temperature, while high PHBV levels were associated with additional, more subtle changes in long-chain polyunsaturated fatty acids. PHBV particle length distributions also varied depending on exposure conditions. These findings suggest that PHBV induces physiological responses distinct from those typically reported for conventional microplastics and highlight the importance of considering multiple stressors in ecotoxicological studies. Full article

The study presents the results of research aimed at developing digital models for determining the operating parameters of railway power supply systems equipped with distributed generation plants based on renewable energy sources (RESs). RESs can be used in railway transport to increase the reliability of power supply to facilities located in areas with insufficiently developed power grids. This primarily applies to consumers, for whom a power failure can lead to significant damage, accidents, and a threat to human life. RES can serve as independent power sources for special-group consumers and can increase energy conversion efficiency. Furthermore, large-scale implementation of renewable energy sources can significantly reduce energy supply costs and improve power quality. The study employs phase-coordinate modeling, which is characterized by the following features: a systems approach, which implies determining operating conditions while considering the properties and characteristics of complex traction and supply networks; versatility, which enables modeling of power supply systems of various structures and designs; and comprehensiveness, which involves calculating normal, emergency, and special operating parameters—crucial for scenarios such as ice melting on catenary wires. The modeling results obtained using the Fazonord AC-DC software (ver. 5.3.5.2) show that RES-based distributed generation plants provide a variety of beneficial effects: reduction in electricity consumption from power system networks; decrease in voltage unbalance and harmonic distortion on the busbars of regional windings of traction substations; and stabilization of voltage levels on current collectors of electric locomotives. Full article

Background: Hexavalent chromium (Cr(VI)) is a widespread environmental toxic heavy metal with strong oxidative properties; however, its immunotoxicity and metabolic mechanisms in rabbit spleen remain largely unclear. Methods: In this study, New Zealand rabbits were exposed to 0, 12.5, 25, and 50 mg/L Cr(VI) (as potassium dichromate, K₂Cr₂O₇) via drinking water for four weeks to investigate splenic damage and the underlying molecular pathways. Spleen pathological injury was evaluated by hematoxylin and eosin (H&E) staining, and the distribution of T cells, B cells, and macrophages was assessed by immunohistochemistry. Antioxidant enzyme activities and antioxidant substance levels were determined using ELISA, and the relative mRNA expression of immune factor genes, antioxidant-related genes, and ferroptosis-related genes was quantified by quantitative real-time PCR (qRT-PCR). In addition, the distribution of iron in splenic tissue was detected by enhanced Prussian blue staining. Results: Our results demonstrate that high-dose Cr(VI) significantly inhibited body weight gain, induced lymphocyte atrophy, vacuolization, and widening of intercellular spaces in the splenic white pulp. Furthermore, Cr(VI) reduced T and B lymphocyte populations, promoted macrophage infiltration and inflammatory cytokine gene expression in a concentration-dependent manner, impaired total antioxidant capacity, and led to a decrease in glutathione (GSH) levels in the spleen. Additionally, Cr(VI) exposure increased iron accumulation, activated the ACSL4–NOX lipid peroxidation cascade, and downregulated GPX4 expression, ultimately triggering ferroptosis. Conclusions: These findings reveal that Cr(VI) causes splenic immune injury by disrupting oxidative homeostasis and inducing ferroptosis, providing novel insights for evaluating immunotoxicity and identifying metabolic targets under Cr(VI) pollution. Full article

Mo–Re alloys serve as critical structural components for high-temperature nuclear reactors, and their irradiation degradation is closely related to the evolution of vacancy-type defects. In this study, heavy-ion and He-ion irradiations were performed under RT to introduce an average displacement damage of 3.5 dpa within the 1 μm-thick surface layer of Mo–Re alloys with Re content up to 47 wt.%. PALS, SPB-DBS and CDB techniques were employed to characterize the size, concentration, depth distribution and local chemical environment of irradiation-induced vacancy-type defects. The results demonstrate that the longer lifetime component of irradiated Mo–Re alloys ranged from 262 to 280 ps, corresponding to medium-sized vacancy clusters. The S parameter of all specimens increased significantly from approximately 0.42 to 0.50, with negligible differences (<0.01) among various Mo–Re alloys. No distinct characteristic peak of Re was observed near 17 × 10⁻³ m₀c at the vacancy sites, which was inconsistent with simulation predictions. Mo–Re alloys exhibit similar vacancy-type defect features to pure Mo, implying weak interactions between Re solute atoms and vacancy-type defects under RT irradiation. Full article

Slamming-induced whipping has been recognized as a key contributor to fatigue damage of large ships operating under severe sea states. However, accurate prediction of whipping responses remains challenging because of complex nonlinear fluid–structure interactions. This study aims to investigate the characteristics of slamming-induced whipping and quantitatively analyze its influence on the fatigue damage of an ultra-large container ship. A three-dimensional fully nonlinear time-domain hydroelastic method, in which the boundary element model is coupled with a Timoshenko beam model, is employed to predict the slamming-induced whipping responses. Segmented model tests in long-crested irregular waves are conducted to provide wave loads of hull girders under severe sea states. The total and wave-frequency vertical bending moments are separated by the fast Fourier transform, and their statistical characteristics are evaluated through probability distributions. Fatigue damage is assessed on the basis of the rainflow counting method and the Palmgren–Miner cumulative damage rule. The contribution of high-frequency whipping responses to fatigue damage is quantitatively evaluated using a fatigue damage factor. It is demonstrated that slamming-induced whipping can significantly amplify fatigue damage by increasing stress amplitudes and cycle counts, particularly under high forward speeds and severe sea conditions. The findings provide a reliable reference for the fatigue design and safety assessment of ultra-large container ships. Full article

Based on measured data from a shale gas well, this study develops a wellbore temperature cycle model and a temperature–pressure coupled finite element model to evaluate cement sheath stress during multi-stage fracturing. Dynamic temperature and pressure boundaries are applied to calculate radial and tangential stresses, while cumulative mechanical degradation and failure modes are assessed using the modified Mohr–Coulomb criterion. The results show that cement sheath temperature changes significantly, and stresses vary periodically with fracturing stages. The injection period is the most critical stage for cement sheath failure. Lower casing pressure and reduced fracturing fluid displacement can improve stress distribution and reduce damage. Higher initial fluid temperature increases radial stress but decreases tangential stress, while shallower horizontal well depth weakens temperature–pressure coupling. Optimizing these parameters can mitigate cement sheath damage, enhance structural integrity, and ensure safe fracturing operations. Full article

Building extraction from disaster scenes is critical for emergency response and post-disaster assessment. Unlike conventional static remote sensing imagery, multi-phase disaster imagery contains scenes spanning early, middle, and late disaster stages, where building morphology, class distribution, and boundary characteristics exhibit significant cross-phase heterogeneity. Such phase-dependent variations substantially increase the difficulty of stable semantic segmentation, particularly under complex damage conditions. To address these challenges, we propose MSS-MambaNet for building extraction from multi-phase disaster imagery. A multi-scale architecture is designed to overcome the limitations of single-scale scanning in Mamba, enabling more effective perception of diverse building morphologies. To enhance feature discrimination, a Dual-Domain Cross-Gated Fusion (DDCGF) module is introduced through complementary interactions between spatial and frequency-domain representations. In addition, a Pixel-Aware Dynamic Weighting (PADW) strategy is developed to adaptively emphasize imbalanced foreground pixels and ambiguous boundary regions, thereby improving segmentation consistency under complex disaster conditions. Extensive experiments demonstrate that MSS-MambaNet consistently outperforms state-of-the-art methods, achieving an average mIoU of 92.78% and mF1 of 96.25% with only 12.37 M parameters. These results indicate that the proposed method effectively handles the heterogeneity of multi-phase data, providing a stable and efficient solution for building extraction from multi-phase disaster imagery. Full article