Search Results (300)

Agrobacterium tumefaciens, a destructive pathogen causing crown gall disease, results in substantial agricultural losses. Traditional chemical and existing biocontrol methods are limited by environmental pollution, pesticide resistance, and low efficacy, while bacteriophages emerge as a promising alternative due to their high host specificity, environmental compatibility, and low resistance risk. In this study, we isolated and characterized a lytic phage (PAT-A) targeting A. tumefaciens, evaluating its biological traits, genomic features, and biocontrol potential. The host strain A. tumefaciens CL-1 was isolated from cherry crown gall tissue and identified by 16S rDNA sequencing. Phage PAT-A was recovered from orchard soil via the double-layer agar method, showing a tadpole-shaped morphology (60 nm head diameter, 30 nm tail length) under transmission electron microscopy (TEM). Nucleic acid analysis confirmed a double-stranded DNA genome, susceptible to DNase I but resistant to RNase A and Mung Bean Nuclease. PAT-A exhibited an optimal MOI of 0.01, tolerated wide pH and temperature ranges, but was sensitive to UV (titer declined after 15 min of irradiation) and chloroform (8% survival at a 5% concentration). Whole-genome sequencing revealed a 44,828 bp genome with a compact structure, and phylogenetic/collinearity analyses placed it in the Atuphduvirus genus (Autographiviridae). Biocontrol experiments on tobacco plants demonstrated that PAT-A significantly reduced crown gall incidence. Specifically, simultaneous inoculation of PAT-A and A. tumefaciens CL-1 resulted in the lowest tumor incidence (12.0%), while pre-inoculation of PAT-A 2 days before pathogen exposure achieved an incidence rate of 33.3%. In conclusion, PAT-A is a novel strictly lytic phage with favorable biological properties and potent biocontrol efficacy against A. tumefaciens, enriching phage resources for crown gall management and supporting phage-based agricultural biocontrol strategies. Full article

Accurately measuring the three-dimensional green quantity (3DGQ) of urban trees is crucial for quantifying carbon sequestration benefits (CSB) in high-density cities. In this study, 540 street trees across 18 species (30 per species) in Shanghai were analyzed to evaluate an Improved Simpson Model (ISM) for UAV-derived crown volume estimation against a traditional Approximate Geometry Model (AGM) and a LiDAR-based point cloud method (PCM). The ISM integrates UAV imagery, edge-based canopy profiling, and Simpson’s numerical integration to account for irregular crown shapes and internal leaf-stem gaps. Results show that ISM achieved consistently lower estimation errors than the benchmark methods. Overall, ISM’s 3DGQ estimates had a root mean square error (RMSE) of approximately 5.2 m³ and a mean absolute error (MAE) of about 4.1 m³, indicating a close match with PCM reference values. This represents a dramatic error reduction, on the order of 90%–95% improvement in RMSE, compared to the conventional AGM approach. Broadleaf species with dense, regular canopies (e.g., Cinnamomum camphora and Platanus × acerifolia) exhibited the highest accuracy, with ISM-predicted volumes deviating only ~1%–2% from field measurements. Even for species with more irregular or porous crowns, the ISM maintained robust performance, yielding smaller errors than AGM and nearly matching the LiDAR-based PCM “ground truth.” These findings demonstrate that the proposed ISM can provide highly accurate 3D crown volume and carbon sequestration estimates in complex urban environments, outperforming existing geometric models and offering a practical, efficient alternative to labor-intensive LiDAR surveys. Full article

Structural optimization focusing on the root fillet radius and the crown and band thicknesses was implemented to prevent rotor–stator interaction-induced resonance, with the objective of enhancing the frequency safety margin for the 4-nodal-diameter mode shape. An ultra-high-head pump–turbine runner is analyzed using an acoustic fluid–structure coupling method to investigate modal characteristics and identify effective design improvements. The results show that increasing the root fillet radius from 0 to 50 mm raises the frequency safety margin from 3.7% to 8.5%, thereby significantly reducing the resonance risk. Likewise, increasing the thickness of the crown, the band, or both leads to higher frequency safety margins, with simultaneous thickening of both components delivering the most improvement. Frequency safety margins continue to rise as the degree of thickening increases. When a runner’s natural frequency is only slightly higher than the corresponding excitation frequency, design measures such as enlarging the root fillet radius and jointly thickening the crown and band effectively expand the frequency safety margin. These findings can provide designers with both qualitative and quantitative references when modifying these structural parameters to mitigate resonance risk. Full article

Background/Objectives: The rotation of maxillary canines represents one of the least predictable movements with clear aligners, particularly in cases requiring rotations greater than 10°, due to the rounded crown morphology and limited aligner grip. The aim of this retrospective study was to compare three different crescent-shaped attachment designs (vertical, horizontal, and oblique) for maxillary canine rotations greater than 10° with clear aligners. Methods: Seventy-eight maxillary canines were retrospectively selected and allocated into three equal groups (n = 26) according to the orientation of the applied attachment: vertical, horizontal, or oblique crescent-shaped attachments. Digital STL models (initial, predicted, and final) were imported into Dolphin 3D software 12.0.63 to assess the accuracy of maxillary canine’s rotation through the comparison between planned and achieved values. Results: Mean rotational accuracy was 55.10% ± 15.60 for the vertical group, 62.40% ± 16.10 for the horizontal group, and 64.60% ± 19.40 for the oblique group. One-way ANOVA showed no statistically significant differences among groups (p = 0.09). Pairwise analysis revealed a statistically significant difference between the oblique and vertical designs (p = 0.05). Conclusions: Attachment orientation may influence the accuracy of maxillary canine rotation with clear aligners, with oblique crescent-shaped attachments showing a trend toward improved rotational control. Full article

Objective: This study aimed to assess the psychosocial impact of stainless steel crowns (SSCs) among primary school children in Dammam, Saudi Arabia, focusing on bullying experiences, child satisfaction, and parental perception. Methods: A cross-sectional survey was conducted in June 2025 among 123 children (mean age 7.8 years; 52% male) from two randomly selected schools. Schools were chosen using simple random sampling from a Ministry of Education-approved list. All children aged 6–10 years with at least one SSC placed for six months or more were eligible. A validated, self-administered questionnaire completed by children and their parents assessed bullying related to SSCs, satisfaction with the crown’s appearance, and perceived impact. Statistical analyses included descriptive statistics, Chi-square tests, and logistic regression to evaluate associations between variables (p < 0.05). Results: Bullying was reported by 39.0% of children, primarily verbal (58.1%), followed by social exclusion (29.1%). Although gender differences in bullying were not statistically significant (p = 0.829), boys more often reported nickname-based teasing (p < 0.001). Only 35.0% of children were satisfied with the crown’s shape and 29.3% with its color. Nearly half (48.8%) felt uncomfortable when asked about it. In contrast, parental satisfaction was higher (69.1%), though only 42.3% believed their child had fully accepted the crown. Conclusions: While SSCs are clinically effective and accepted by most parents, a notable proportion of children experience bullying and aesthetic dissatisfaction. These findings highlight the need for child-centered care and consideration of esthetic alternatives. Full article

This study focuses on a large-span highway tunnel in argillaceous soft rock. Numerical simulations were conducted to investigate the mechanical characteristics of the tunnel, constructed using the Double Side Drift Method (DSDM), and the effects of the offset distance between drift faces. Subsequently, field monitoring was performed to analyze the deformation patterns of the primary support at typical cross-sections. The results indicate the following: (1) During DSDM construction in argillaceous soft rock, the crown settlement of the left drift is the largest, while that of the central drift is the smallest. The left and right drifts converge inward, whereas the central drift expands outward, resulting in overall inward convergence of the tunnel section, with the left drift exhibiting a larger convergence. The crown settlement and horizontal convergence induced by excavation of the upper benches of each drift are greater than those caused by the lower benches. (2) The stresses in the primary support increase rapidly after excavation of each segment and then tend to stabilize. The maximum tensile stress occurs at the left haunch, reaching 0.41 MPa, while the maximum compressive stress occurs at the left arch waist, reaching 14.56 MPa. After the tunnel excavation is completed and the section is enclosed, the stress on the left side is significantly higher than that on the right, indicating an eccentric stress state. The plastic zones in the surrounding rock exhibit a butterfly-shaped distribution, mainly concentrated at the haunches and arch springings on both sides. (3) As the offset distance decreases, the deformation of the primary support reduces, whereas the stress and the area of the surrounding rock plastic zones increase. When the offset distance is less than 15 m, both the stress in the primary support and the plastic zone area increase sharply, suggesting that the drift face offset distance should not be less than 15 m. (4) Field monitoring shows that the maximum cumulative crown settlement of the primary support reaches 30.2 mm, and the cumulative horizontal convergence of the section is 35.6 mm, both of which are below the reserved deformation allowance. Full article

To address the limitations of traditional energy dissipation technologies, such as difficulty in arranging energy dissipators due to narrow river valleys and complex geological conditions and the low energy dissipation efficiency of existing air jet collision methods, this study proposes a novel structural form of a horizontal opposing jet energy dissipator. Water is diverted to the open area downstream of the reservoir hub via diversion pipelines, and energy dissipation is achieved through horizontal opposing collision of jets in the air. Focusing on this new energy dissipator, numerical simulations combined with physical experiments were conducted to investigate its energy dissipation characteristics, with the dimensionless parameters l/d (collision distance/pipeline diameter) and Reynolds number (Re) as the main variables. The results indicate that two opposing jets formed a crown-shaped water jet after horizontal collision in the air. The rising height in the Z-direction and expanding width in the Y-direction of the crown-shaped water jet exhibit a negative correlation with l/d and a positive correlation with Re. Energy dissipation was achieved through jet collision, mixing, friction, diffusion, aeration, and fragmentation in the air. This energy dissipation method improved the energy dissipation rate by extending the collision time and mixing length of jets in the air. The primary factors influencing the energy dissipation rate were l/d and Re. Under the study conditions, the energy dissipation rate of jet collision in the air ranged from 16.25% to 39.54%. The energy dissipation efficiency exhibits a negative correlation with l/d and a positive correlation with Re. This study provides a new approach for energy dissipation in hydraulic engineering. Full article

Against the backdrop of accelerating population aging, urban green spaces have become primary venues for elderly daily activities, with their winter thermal comfort emerging as a critical determinant of senior wellbeing. However, existing studies lack quantitative guidelines on how plant characteristics affect thermal comfort, limiting age-friendly design. Thirty representative landscape space sites (waterfront, square, dense forest, and sparse forest) in Beijing’s Zizhuyuan and Taoranting Parks were analyzed through microclimate measurements, 716 questionnaires, and scoring evaluations, supplemented by PET field data and ENVI-met simulations. A scoring system was developed based on tree density, plant traits (height, crown spread), and spatial features (canopy closure, structure, enclosure, and evergreen coverage). Key findings: (1) Sparse forests showed the best overall thermal comfort. Square building spaces were objectively comfortable but subjectively poor, while waterfront spaces showed the opposite. Dense forests performed worst in both aspects. (2) Wind speed and humidity were key drivers of both subjective and objective thermal comfort, and differences in plant configurations and landscape space types shaped how these factors were perceived. (3) Differentiated optimal scoring thresholds exist across the four landscape space types: waterfront (74 points), square building (52 points), sparse forest (61 points), and dense forest (88 points). (4) The landscape space design prioritizes sparse forest spaces, with moderate retention of waterfront and square areas and a reduction in dense forest zones. Optimization should proceed by first controlling enclosure and shading, then adjusting canopy closure and evergreen ratio, and finally refining tree traits to improve winter thermal comfort for the elderly. This study provides quantitative evidence and optimization strategies for improving both subjective and objective thermal comfort under diverse plant configurations. Full article

Despite the growing adoption of 3D-printed resin materials, limited evidence exists on how clinical procedures such as scaling impact their surface integrity. This in vitro study evaluated the effect of different scaling methods on the roughness of five 3D-printed resin materials. Disc-shaped specimens from five commercially available 3D-printed crown materials (Crowntec, Varseosmile, Freeprint, Ezprint, and C&B Nextdent) were fabricated. Each material group (N = 30) was subjected to three scaling techniques: stainless-steel manual, plastic, and piezoelectric ultra-sonic scalers. Surface roughness (Ra) was quantified using a non-contact profilometer before and after scaling. One-way ANOVA was used to analyze the data. All the crowns exhibited increased roughness when treated with ultra-sonic scalers compared to the other scalers, and this was significant (p < 0.05) for all except VarseoSmile. Compared to the other crowns, Freeprint crowns (0.07 ± 0.04 µm) showed the greatest roughness change with plastic scalers, which was significant (p < 0.05) compared to C&B Nextdent crowns (0.001 ± 0.03 µm). For hand and ultra-sonic scalers, no significant differences were found among the crown types (p > 0.05). In conclusion, ultra-sonic scalers, while efficient, may increase surface roughness, potentially enhance plaque retention, and compromise prosthesis longevity. Full article

Traditional centennial olive groves represent ecologically valuable agroecosystems that support both biodiversity and cultural heritage across Mediterranean landscapes. On Lesvos Island, Greece, which marks the westernmost limit of the Persian squirrel (Sciurus anomalus) distribution, these centennial olive trees serve as essential nesting resources for this regionally Vulnerable species. However, the tree-level mechanisms determining den-site suitability remain insufficiently understood. We examined 288 centennial olive trees, including 36 with confirmed dens, integrating structural, physiological, and thermal metrics to identify the attributes influencing den occupancy. Our results showed that squirrels consistently selected older and taller olives with broad crowns and high photosynthetic activity, indicating a preference for vigorous, architecturally complex trees that provide stable microclimatic conditions. Infrared thermography revealed that occupied trees exhibited lower trunk temperature asymmetries and stronger thermal buffering capacity, highlighting the role of microclimatic stability in den-site selection. Overall, our findings show that den-site selection in S. anomalus is shaped by the interplay of structural maturity, physiological performance, and thermal coherence. By linking tree function to den-site suitability, our work advances a mechanistic understanding of microhabitat selection and emphasizes the importance of centennial olive trees as biophysical refugia within traditional Mediterranean agroecosystems. Full article

To investigate the impact of subsurface karst cavities on the stability of pipe jacking construction, this study utilizes the Yunnan Central Water Diversion Project as a real-world case. Employing ABAQUS finite element software to establish a numerical model, it systematically analyzes construction stability under the specific condition of “karst cavities present ahead of the excavation direction” in karst formations. The research focuses on examining the effects of four key scenarios on the displacement and stress response of surrounding rock and pipe segments. These conditions specifically include the following: tunnel burial depth (10 m, 15 m, 20 m, 25 m), cavity diameter beneath the tunnel (1–4 m), cavity filling status, and distance between the cavity and the tunnel (1–4 m). The study reveals that in composite stratum tunnel construction, when cavities exist in the strata ahead, multi-area displacements increase progressively with cavity size. Displacement changes accelerate and magnify when the cutting face of the jacking machine approaches within approximately 2.5 m of the cavity. However, no significant difference is observed between soft plastic clay reinforcement and slurry reinforcement effects. When composite stratum tunnels traverse beneath karst caves, the maximum upward bulge at tunnel bases occurs at 1-meter diameter caves, reaching approximately 2.5 mm. When the diameter of the cave increases to 4 m, the arching settles to a maximum. As tunnel burial depth increases, the arch base rises while the crown sinks, with settlement magnitude exceeding bulge amount. The displacement and stress fields from the initial excavation phase become disturbed, intensify, and then stabilize. When the jacking machine reaches directly above the cavern, stress at the crown base increases while stress at the crown top decreases. The pipe bottom exhibits uplift, and the pipe top shows reduced settlement directly above the cavern. Cavern filling has a minor effect on pipe-segment displacement, with segments deforming into an approximate elliptical shape. At the completion stage of excavation, the maximum Mises stress occurs at the top of the launch-end pipe segment. While cavern-related factors have a limited influence on the pipe-segment Mises stress, this stress gradually increases as excavation progresses. Full article

To explore new possibilities in topological materials, we designed a tetrafunctional crosslinker composed of a [c2]daisy-chain rotaxane framework. In this study, a novel topological network polymer was successfully synthesized via an addition reaction between 3,6-dioxa-1,8-octanedithiol (DODT) and a tetrafunctional crosslinker, a [c2]daisy-chain rotaxane constructed from dibenzo-24-crown-8 ether (DB24C8) units and bearing long-chain alkenes on its four benzene rings. The resulting network polymer exhibited both high stiffness and toughness, along with excellent shape-memory properties. These characteristics were governed by a balance between plastic and elastic deformation originating from the DODT and rotaxane domains, respectively, highlighting a new design strategy for the creation of advanced topological materials. Full article

Transparent CAD/CAM monolithic ceramics are increasingly used in dentistry due to their combination of high strength, esthetics, and durability, achieved through high yttria content and multilayered systems. This study evaluates the mechanical behavior of four widely used CAD/CAM ceramics, correlating their performance with microstructural characteristics. Bar-shaped specimens (n = 10 per material, for each test) of ZOLID^® FX ML (ZF), IPS E.MAX^® CAD (MC), E.MAX^® ZIRCAD (ZM), and KAT-ANA^® STML (KS) (all A2 shade) were prepared and sintered according to manufacturers’ protocols. Flexural strength and elastic modulus were measured using three-point bending, and Vickers hardness was determined separately. Statistical normality was confirmed with the Kolmogorov–Smirnov test. Flexural strength ranged from 252.8 ± 39.8 MPa (MC) to 547.6 ± 125.7 MPa (ZM), elastic modulus from 65.8 ± 6.5 GPa (MC) to 94.1 ± 5.8 GPa (KS), and hardness from 4.2 ± 0.2 GPa (MC) to 9.6 ± 0.6 GPa (ZF). High-elastic-modulus materials (KS, ZM) can better resist deformation under occlusal loads, improving long-term stability of posterior crowns, bridges, and implant-supported restorations. High hardness (ZF) provides superior wear resistance and preserves occlusal anatomy over time, making it suitable for thin-shell restorations and high-stress functional surfaces. Materials with lower modulus and hardness (MC) are more suitable for intra-coronal restorations or thin veneers where stress shielding and material compliance are advantageous. These findings support material selection based on mechanical demands, and further clinical studies are needed to confirm long-term performance. Full article

This study employs the UCMW (Universal crown mill with work roll shifting) cold rolling mill as the research object, focusing on the critical process parameter of single-taper profiles for both the work roll and intermediate roll. By establishing an integrated finite element model of the roll-strip system, this analysis examines the influence patterns of single-taper profiles applied to the work roll, the intermediate roll, and their combined configuration on strip shape. The research demonstrates that when the work roll utilizes a single-taper profile, the strip shape approximates a rectangular profile at a shift amount of −75 mm and exhibits a concave profile at −95 mm. For the intermediate roll employing a single-taper profile, the strip shape manifests a convex profile within the shift range of −150 mm and transitions to an M-shape at −180 mm. Utilizing the combined roll profiles induces a gradual transition in strip shape from convex to concave within the shift range of −50 mm to −95 mm. Comparative analysis indicates that at a shift of −50 mm, the combined roll profiles yield a shape closer to rectangular; at −75 mm, the work roll profile produces superior results; at −95 mm, both the work roll profile and the combined profiles result in concave shapes, with the combined configuration exerting the most pronounced effect. This investigation furnishes a theoretical foundation for roll profile optimization in rolling mills and the enhancement of strip dimensional precision. Full article

The fragile ancient ‘Shuikoulin’ forests, which provide critical habitats for the critically endangered Blue-crowned Laughingthrush, are increasingly degraded by soil contamination and heavy metal pollution. This study examines the rhizosphere environment of four key ancient tree species in the bird’s core habitat, focusing on soil properties, heavy metal accumulation, and the structure of arbuscular mycorrhizal (AM) fungal communities. The results revealed that Liquidambar formosana showed the highest total nitrogen (TN) and available phosphorus (AP), whereas Quercus chenii had the lowest soil organic matter (SOM). The primary heavy metal contaminant across all tree species was Cd (Igeo > 2), followed by the metalloid As. We detected 41 AM fungal species spanning 7 genera, with Glomus dominating (84.19% relative abundance). OTU richness was highest in Cinnamomum camphora and L. formosana (110 each), followed by Q. chenii (88) and Castanopsis sclerophylla (75). Structural equation modeling indicated that soil nutrients (TN, TP, AP, SOM) suppressed the accumulation of V, Cr, Ni, and Cu, thereby indirectly favoring Glomus and Paraglomus. In contrast, higher pH and total potassium (TK) levels promoted Co and Zn bioavailability and negatively affected Acaulospora and other minor genera. Tree species identity directly modulated these interactions. Our findings demonstrate that ancient tree species shape AM fungal assembly through distinct rhizosphere geochemical niches, providing a mechanistic basis for restoring degraded habitats critical to endangered species conservation. Full article