Search Results (86)

Background: Cardiac erosion after transcatheter closure of secundum atrial septal defect (ASD) is a rare (0.1–0.3%) but potentially life-threatening complication. Available evidence remains limited to isolated case reports and small case series. Methods: A case-based review was conducted in accordance with CABARET recommendations. PubMed, Scopus, Web of Science, and the Cochrane Central Register of Controlled Trials (CENTRAL) were searched from inception through January 2026. Adult cases with anatomically confirmed aortic or aorto-atrial erosion after transcatheter closure of a secundum ASD were included. Clinical, anatomical, procedural, imaging, management, and outcome data were synthesized descriptively. An illustrative case with aorto-atrial erosion was included. Results: A total of 40 cases, including the present case, were identified. Median age was 39.5 years, and 27 were female. Chest pain was the most common symptom, reported in 16 cases, whereas six patients were asymptomatic at diagnosis. Median time to erosion was 81 days (range, 0.25–4745 days). A deficient rim was reported in 22 patients, and device oversizing in 17 patients. All erosions involved the aortic wall, most frequently at the atrial roof adjacent to the non-coronary sinus. Aorta-right atrial and aorta-left atrial were the predominant anatomical patterns, reported in 21 and 14 patients, respectively. Surgical intervention was required in 36 cases, which consisted of device explantation with atrial and/or aortic repair. Conclusions: Aortic and aorto-atrial erosion after transcatheter secundum ASD closure is an uncommon but severe complication with heterogeneous clinical presentation and timing. Among published erosion cases, female sex, a deficient retro-aortic rim, device oversizing, and mild aortic root dilation were recurrent characteristics. Careful anatomical assessment, multimodality imaging, and continued follow-up remain essential for early recognition of cardiac erosions. Full article

Maintenance is crucial for the durability of the existing building stock and should be perceived as an opportunity to improve the built environment. The implementation of thermal retrofitting measures to the building’s envelope enhances global energy performance, which is economically and environmentally beneficial. Building-related energy consumption during the operation phase is key to tackling carbon neutrality and climate change. Introducing thermal retrofitting within the context of maintenance planning can be cost-optimizing, as it reveals the technical–economic synergy between building pathology and energy efficiency. Maintenance activities and energy demand throughout the building’s service life influence life-cycle costs (LCCs). Decision-making based on LCC awareness is an advantage for owners. This study discusses the impact of implementing an optimal retrofitting solution (ORS), according to different maintenance strategies, on the LCC of an existing single-family home. The ORS comprises the following measures: adding an external thermal insulation composite system (ETICS) to external walls, extruded polystyrene (XPS) panels to the roof, and replacing the existing windows with others with improved thermal performance. The three maintenance strategies involve different complexity levels, concerning the type, number and timing of activities. Moving beyond isolated assessments, this study develops an integrated framework that bridges based on two existing background methodologies, involving optimal thermal retrofitting and condition-based maintenance planning, which, combined with new research, enable the assessment of maintenance, energy and global LCC for a time horizon of 100 years. The evaluation of energy-related LCC is based on simulations. The results indicate that these costs represent the majority of the global LCC. The ORS has a considerable positive impact on energy and global LCC. Adopting a maintenance strategy characterized by fewer planned activities and an earlier schedule of replacement interventions, which determines the implementation of the retrofitting measures, is better in terms of LCC savings. Full article

Longwall paste backfilling mining is a core sustainable green mining technology for coal resources under buildings, railways and water bodies (BRW), yet its large-scale application is severely restricted by the sequential mining–isolation–backfilling–curing operation mode that causes low production efficiency and poor economic feasibility, which hinders the sustainable exploitation of BRW coal reserves and the ecological protection of mining areas. Taking the E1302-B paste backfilling face of Gaohe Coal Mine as the engineering background, this study systematically identified the key efficiency-restricting factors considering the face’s complex geological conditions (maximum roof–floor undulation 300 mm, 72.6% of roof–floor dip angle >1° and irregular cross-section), including low isolation efficiency, cumbersome backfilling process, prolonged paste curing time and insufficient system operation controllability. Technological innovations were carried out from four core dimensions: high-efficiency isolation, high-efficiency backfilling, accelerated curing and intelligent safety control, and a high-efficiency integrated technology system for longwall paste backfilling mining was thus formed, which realizes the synergistic improvement of mining efficiency, economic benefits and sustainability performance. Industrial test validation demonstrated that the technical system significantly boosts the efficiency of isolation, backfilling and solidification in the backfill mining cycle, cutting the time of a single backfill mining operation cycle by 57%. The annual production capacity of the E1302-B face was increased to 0.81 Mt, with a comprehensive backfilling mining cost of 466.63 CNY/t, an annual economic benefit of 108.03 million CNY and a static investment return rate of 48.96%. The E1306 face achieved an even higher annual production capacity of 1.12 Mt with a static investment return rate of 74.94%. This technology system effectively breaks the efficiency and economic bottlenecks of traditional longwall paste backfilling mining, realizes the dual improvement of backfilling mining efficiency and economic benefits, and further releases the ecological, resource and economic sustainability value of paste backfilling mining. It provides technical support and practical approaches for the large-scale application of longwall paste backfilling mining, and lays a solid foundation for the sustainable development of the coal industry under the dual-carbon goal, especially for the balanced development of coal resource exploitation and mining area ecological protection. Full article

While dissolution dominates the genesis of karst systems, physical erosion processes also play a significant role in their development. Lowering of the water table exposes caves to vadose conditions, reducing roof-supporting buoyancy and potentially leading to catastrophic conduit ceiling failure and cave collapse. The locations and extents of collapse areas are not always identifiable at the landscape surface. High-resolution topographic data derived from LiDAR were used to develop a digital elevation model (DEM) that isolates areas that may have sustained episodes of cave collapse and improves our understanding of past hydrogeological and geomorphological conditions of the system. Cave level delineation from LiDAR data was used to assign elevations to cave entrances. Spatial susceptibility to past collapse was evaluated using a weighted multi-criteria analysis that integrated terrain slope, proximity to mapped cave entrances, and distance to surface streams. Areas identified as having a high likelihood of collapse spatially coincide with cave level contacts and known karst windows and terraces, indicating that this replicated methodology is effective as an initial survey tool for identifying collapse-prone areas in karst landscapes. Full article

This study investigates direction-dependent roof speed-up factors for both isolated and interacting building configurations and evaluates their influence on the energy-yield potential of small wind turbines (SWTs) in urban environments. A combined approach was adopted: A theoretical framework and wind-tunnel experiments were developed to establish a general understanding of the meteorological, aerodynamic, and energetic parameters governing rooftop wind energy conversion and to derive characteristic roof speed-up factors for standardized flat-roof configurations. Wind-tunnel experiments were conducted for four distinct building scenarios, differing in layout and surrounding interaction, under three representative wind directions. High-resolution velocity measurements were acquired at multiple rooftop positions and elevations to capture detailed flow-acceleration and turbulence patterns. The resulting data were then applied in a case study for a representative urban site in Aachen, Germany. The measured directional speed-up factors were combined with a Weibull wind-speed distribution and a representative SWT power curve to estimate annual energy yields. The results reveal pronounced spatial and directional variability in wind acceleration, with localized increases of up to 25%. These variations translate into substantial differences in expected turbine performance depending on mounting height, placement, and prevailing wind direction. To facilitate further research and practical use, the complete dataset is published openly as a benchmark for computational fluid dynamics (CFD) validation and as a planning resource for rooftop turbine siting. The study underscores the importance of local aerodynamic effects in urban wind-energy design and provides a methodological framework that links controlled wind-tunnel data with real-world wind statistics. Full article

Passive building ventilation features, such as wind towers, can help meet rising cooling and ventilation demands in hot, arid regions. However, most prior studies rely on scaled models or isolate single design parameters, limiting holistic insight. This study conducts a full-scale, validated computational fluid dynamics (CFD) parametric analysis of wind tower geometry and its impact on ventilation efficiency in semi-enclosed spaces. Five geometric properties are investigated: tower shape, roof type, number of shafts, separator height, and number of louvres. Additionally, the sensitivity of the optimal configuration to wind speed, wind direction, and louvre orientation is assessed. Results from 88 CFD cases highlight strong interactions among design parameters and show that straight towers with curved roofs consistently perform best. Compared with a tower with six shafts, a flat internal roof, and downward-facing louvres, an optimized tower with four shafts, a convex internal roof, and upward-facing louvres increases airflow rate by a factor of 2.7 and occupied-zone air velocity by 45%, underscoring the importance of holistic geometric optimization. Full article

Urban heat islands pose intensifying threats to public health, equity, and urban livability as climate change amplifies temperature extremes. This systematic review synthesizes evidence from 33 primary studies (2021–2025) examining health impacts, mitigation strategies, and policy integration. The analysis focuses on interaction mechanisms, specifically how mitigation strategies differentially reduce health burdens across vulnerable populations, to advance systems-level understanding of urban heat dynamics. Following PRISMA guidelines, the review examined these mechanisms across three interconnected domains: health burdens, physical mitigation effectiveness, and post-pandemic policy synergies. Findings reveal profound inequities in heat exposure and associated health outcomes, with disadvantaged populations experiencing 26–45% higher heat-related mortality risk and 3–4 °C greater exposure than affluent communities, even after controlling for income. Physical mitigation strategies show measurable effectiveness, providing 1–6 °C cooling from green infrastructure and 2–22 °C from cool surfaces. Optimal interventions vary by socioeconomic context, with urban trees being more effective in disadvantaged areas, while cool roofs are better suited to affluent zones. COVID-19 natural experiments demonstrated 30–50% anthropogenic heat reductions, revealing strategic opportunities for integrating heat mitigation with 15-Minute City planning and work-from-home normalization. Effective implementation requires moving beyond isolated interventions toward spatially differentiated, equity-centered strategies aligned across planning, transportation, and governance domains. The post-pandemic period presents a critical window for embedding heat mitigation into broader urban transformation agendas. Full article

Background/Objectives: Pulsed field ablation (PFA) is increasingly used for pulmonary vein isolation (PVI). One of the emerging single-shot PFA catheters is the variable-loop circular catheter (VARIPULSE™, Biosense Webster, Inc.) which is fully integrated into a three-dimensional mapping system. However, the evidence for the feasibility of ablation of non-pulmonary vein targets is still limited using the VARIPULSE catheter. In this study, we summarize our experience in PVI and mapping/ablation of non-pulmonary vein sites in patients with atrial fibrillation (AF) and complex atrial substrate and arrhythmias using the VARIPULSE catheter. Methods: All patients with paroxysmal or persistent AF who underwent catheter ablation using the VARIPULSE catheter were retrospectively included. PVI was performed in all patients. Spontaneous or inducible atrial flutters were mapped and ablated. Empiric lines were performed at the operator’s discretion. Acute outcomes and complications were analyzed. Results: the study included 60 patients; 25 (41.6%) were females and mean age was 67.15 ± 9.01 years. Thirty four (60%) had persistent AF and six (10%) patients had atrial flutter as the initial rhythm during the index procedure. All patients had PVI using the PFA as per protocol. Most of the patients (76.7%) had non-pulmonary vein ablation sites; posterior wall isolation was performed in 25 (41.7%) patients, roof line in 9 (15%) patients, anterior line in 16 (26.7%) patients, cavotricupsid isthmus in 11 (18.3%) patients and superior vena cava isolation in two (3.3%) patients. Overall, 27 patients had atrial flutters during the index procedure that were mapped and ablated using the VARIPULSE catheter. All had termination of atrial flutter except for one patient. Major complications were not detected. Conclusions: Mapping and ablation of atypical atrial flutter and non-pulmonary vein targets are feasible and safe using the VARIPULSE platform. Full article

This study quantifies vertical earth pressure on the roofs of box culverts under high fills in valley terrain using centrifuge model tests with expanded polystyrene (EPS) geofoam for load mitigation. We compare buried-type culverts with valley-terrain high-fill culverts and isolate the effects of the EPS installation height and panel thickness on the roof pressure and the associated concentration factor. The analysis of fill settlement elucidates the terrain-dependent load reduction mechanism and the efficacy of EPS panels. The results show that the roof pressure increases with EPS installation height but decreases and then plateaus once the panel thickness exceeds 75 cm; the load reduction benefit weakens when the installation height exceeds 2 m. Optimal performance is achieved with panels installed at 2 m and with a 75 cm thickness, which lowers applied loads while maintaining structural stability. These findings clarify soil–structure interactions in complex topography and provide practical guidance for deploying EPS in high-fill valley projects. Full article

In the context of China’s rural revitalization strategy, improving the livability and sustainability of traditional dwellings in border regions has become a critical priority. This study examines Chinese–Korean houses in border villages, where field investigations and quantitative analysis reveal persistent challenges: poor indoor thermal comfort and high energy consumption due to outdated building envelopes and inefficient heating systems. To address these issues, we propose an integrated retrofitting solution that combines building-integrated photovoltaics (BIPV) and ground-source heat pump (GSHP) technologies. Unlike previous studies focusing on isolated applications, our approach emphasizes the synergistic integration of active energy generation and high-efficiency thermal regulation, while preserving the architectural and cultural identity of traditional dwellings. Pilot results demonstrate significant improvements in PMV (Predicted Mean Vote) and economic viability, and achieve a high level of esthetic and cultural compatibility. Modular BIPV integration provides on-site renewable electricity without altering roof forms, while GSHP ensures stable, efficient heating and cooling year-round. This solution offers a replicable, regionally adaptive model for low-carbon rural housing transformation. By aligning technological innovation with cultural preservation and socioeconomic feasibility, the study contributes to a new paradigm of rural development, supporting ecological sustainability, ethnic unity, and border stability. Full article

By designing and conducting indoor model tests on single piles and 2 × 2 pile groups under four working conditions—underlying cave, overlying cave, pile penetrating underlying cave, and beaded caves—the failure mode of the roof was explored, and its ultimate bearing capacity was analyzed and compared. Unlike previous studies that focused on single piles in isolation, this paper combines scaled laboratory tests with validated 3D finite element analysis to systematically compare the bearing behaviors of single piles and pile groups under different karst roof conditions. After verifying the model in ABAQUS using the experimental parameters, the researchers established a 3D model of single piles and 2 × 2 pile groups, considering different roof thicknesses, roof spans, cave heights, pile-hole eccentricities, and roof inclination angles. The bearing capacities of single piles and pile groups were analyzed and compared, and the bearing-capacity-improvement factors of pile groups under various working conditions were proposed. The research results show that increasing roof thickness enhances the bearing capacity of both single piles and pile groups, with single piles experiencing more significant improvements. Pile groups boost roof bearing capacity by 455.6% compared to single piles. Conversely, larger roof spans reduce the bearing capacity of both pile types, though pile groups show greater vulnerability to span-related reductions. Notably, increasing pile-hole eccentricity significantly improves the bearing capacity of both configurations. When roof inclination increases, bearing capacity decreases for both systems, with single piles demonstrating greater susceptibility to inclination-induced weakening. These findings reveal distinct mechanical behaviors: pile groups offer stability advantages against span and inclination changes, while single piles benefit more from thickness increases. This divergence highlights the importance of aligning pile configuration with specific structural parameter requirements in engineering design; under different roof sensitivity factors, the bearing capacity improvement of 2 × 2 pile groups relative to single piles is different, and several pile group bearing-capacity-improvement coefficients for five roof sensitivity factors are summarized, and the corresponding and interpolated pile-group bearing-capacity-improvement coefficients are selected when selecting; the influence of the five sensitivity factors is ranked as follows: pile-hole eccentricity > roof thickness > inclination angle > roof span > cave height. Full article

Studies of microbial degradation of historic woods are essential to help protect and preserve these important cultural properties. The USS Cairo is a historic Civil War gunboat and one of the first steam-powered and ironclad ships used in the American Civil War. Built in 1861, the ship sank in the Yazoo River of Mississippi in 1862 after a mine detonated and tore a hole in the port bow. The ship remained on the river bottom and was gradually buried with sediments for over 98 years. After recovery of the ship, it remained exposed to the environment before the first roofed structure was completed in 1980, and it has been displayed under a tensile fabric canopy with open sides at the Vicksburg National Military Park in Vicksburg, Mississippi. Concerns over the long-term preservation of the ship initiated this investigation to document the current condition of the wooden timbers, identify the fungi that may be present, and determine the elemental composition resulting from past wood-preservative treatments. Micromorphological characteristics observed using scanning electron microscopy showed that many of the timbers were in advanced stages of degradation. Eroded secondary cell walls leaving a weak framework of middle lamella were commonly observed. Soft rot attack was prevalent, and evidence of white and brown rot degradation was found in some wood. DNA extraction and sequencing of the ITS region led to the identification of a large group of diverse fungi that were isolated from ship timbers. Soft rot fungi, including Alternaria, Chaetomium, Cladosporium, Curvularia, Xylaria and others, and white rot fungi, including Bjerkandera, Odontoefibula, Phanerodontia, Phlebiopsis, Trametes and others, were found. No brown rot fungi were isolated. Elemental analyses using induced coupled plasma spectroscopy revealed elevated levels of all elements as compared to sound modern types of wood. High concentrations of boron, copper, iron, lead, zinc and other elements were found, and viable fungi were isolated from this wood. Biodegradation issues are discussed to help long-term conservation efforts to preserve the historic ship for future generations. Full article

Significant risk of water and sand inrushes is commonly encountered during coal seam mining when thin bedrock is directly overlain by thick, water-bearing, unconsolidated layers. Achieving effective strata control and establishing reliable water-isolating mechanisms under these conditions represent critical scientific and technological challenges for safe mining operations. Furthermore, this is a vital research direction for advancing the extraction limit (or recovery height) in coal seams. Initially, drawing on key stratum theory, ground pressure behavior patterns, and mining operation characteristics, the weathered zone was identified as the critical grouting horizon. During the initial mining stage, the first two periodic weighting intervals (approximately 60 m) were identified as the key area. Subsequently, a strategy of high-pressure grouting was proposed to modify the weathered stratum. Numerical simulation methods were employed to optimize the grouting parameters, with the core specifications determined as follows: grouting pressure ≥30 MPa, water–cement ratio of 0.7:1, and grouting hole spacing ≤30 m. Ultimately, a grouting system was designed that used directional drilling from the surface to access the weathered zone, followed by branched horizontal boreholes for staged high-pressure grouting. The borehole trajectory was predominantly L-shaped. Field implementation demonstrated that the grouting intervention increased the first weighting span by an average of 17.3%. Critically, no water inflow was observed throughout the initial caving period, and significant roof falls or rib spalling were effectively mitigated. This confirmed a substantial improvement in key stratum stability, ensuring the safe and efficient advancement of the mining face. This study provides essential technical support and a practical model for safely and efficiently extracting coal seams under thin bedrock under similar complex hydrogeological conditions. Full article

The mastic asphalt mixture (MA) is one of the first mineral and asphalt mixtures used in history. Its composition and structure allow it (the mixture) to be produced both in industrial conditions (in mineral and asphalt mixing plants) and in field conditions—in mobile boilers (especially when the produced mixture is used to repair damaged surface). The high proportion of the sand fraction makes the mixture highly workable, allowing it to be laid/incorporated without special equipment. MA, however, also has some drawbacks. The asphalt content is higher than in other mixtures, which can make it prone to plastic deformation. Mastic asphalt requires higher processing temperatures than other “hot” mixtures. Mastic asphalt mixtures are installed as road pavement layers and, because of their high density, as the protective layer on roof felt isolation on bridge decks. The high temperature of embedding creates a risk of damaging the roof felt, as its typical temperature resistance is lower than 180 °C, whereas the temperature of the mastic asphalt mixture is higher. The use of zeolites can enable reconciliation of technological requirements of mastic asphalt and asphalt roof isolation. The mixes MA 8 and MA 11 containing 0 and 5% of two types of zeolites and asphalt binders 35/50 or elastomer-SBS-modified asphalt binder PMB 25/55-60 were used in the research. Laboratory tests revealed that the addition of a 5% amount of zeolite by asphalt mass makes it possible to reduce the mastic asphalt laying temperature by up to 30 °C, which seems to be very important from ecological, economical, and pavement durability points of view. Full article

Hillside buildings are particularly vulnerable to earthquakes owing to their structural configuration; however, research addressing this issue remains limited. This study investigates the effectiveness of high-damping rubber bearings (HDRBs) in enhancing the seismic resilience of hillside structures. Five numerical models were analyzed using non-linear time-history (NTH) analysis, including two flat-plane structures (one isolated and one with a fixed base) and three dropped-layer structures on hillside terrain (one with base isolation, one with inter-story isolation, and one with a fixed base). Deformation history integral (DHI) modeling was employed to simulate the HDRBs. Six earthquake ground motions from the PEER database and one scaled from 0.2–0.8 g were used to assess the seismic responses of the buildings. The results indicate that HDRBs significantly improved the seismic performance. The flat-plane isolated system (FIS) model achieved a nearly 90% reduction in peak roof acceleration compared to fixed-base structures. The dropped-layer isolated system (DIS) and dropped-layer inter-story isolated system (DIIS) models exhibited reductions of approximately 80% in the peak roof acceleration. Furthermore, the isolated structures demonstrated up to 78% reduction in the maximum inter-story drift, along with significant decreases in the story shear forces and overturning moments. Compared with non-isolated dropped-layer structures, the DIS and DIIS models showed reductions of 70% and 55% in the base shear force, respectively. The results highlight the efficacy of HDRBs in energy dissipation and their significant role in enhancing the seismic resilience of mountain structures. Full article