Search Results (4,712)

Numerous studies have demonstrated that tooth-supported dental guides improve the accuracy of implant placement. However, current manufacturing procedures and available materials are not yet optimal and may still lead to deviations from the planned implant position. The influence of the surgeon’s manual force on the deformation of dental guides during implant placement has not yet been sufficiently investigated. Therefore, this study evaluates the mechanical behavior of dental guides using finite element analysis (FEA) in order to assess the influence of the surgeon’s hand force during clinical application. Finite element simulations of deformation and stress were performed for four types of tooth-supported dental guides, including cantilever dental guides with free ends and beam-type guides with a large span between the supporting teeth. The manual force applied by the surgeon was arbitrarily set to 30 N. Simulations were conducted for five commonly used biocompatible polymer materials: Stratasys MED610, VeroGlaze MED620, EOS PA2200, Formlabs FLSGAM01, and Stratasys ULTEM 1010. The numerical results quantified the deformation of dental guides caused by the applied manual force during surgical manipulation. For all analyzed guide designs, the deflection was primarily influenced by the arm length, i.e., the distance between the support and the point of force application. Based on the obtained results, design diagrams were developed to provide guidelines for the design of beam-type (A and A1) and cantilever-type (B and B1) tooth-supported dental guides. Full article

Background: Auricular keloids and ear helix deformities are undesirable and aesthetically unpleasing deformities that can cause significant patient psychologic and self-esteem problems. Pressure therapy for keloids is well documented to be an effective non-invasive treatment modality. However, current devices lack comfort and aesthetic appeal to deliver the pressure forces required effectively and uniformly. This work aims to highlight some different pressure therapy approaches for the management of keloids and irregularities in the ear helix morphology. Methods: A case series of four patients presenting with auricle keloids of various sizes and at different locations secondary to ear piercing and one case of congenital helix deformity were treated successfully with pressure therapy devices. The device designs varied based on the keloids’ characteristics and patients’ preferences and involved wire-based spring-activated appliances resembling ear rings for moderate keloid lesions, modified double-spring systems for large or elongated lesions, and magnet-based devices. A pair of inert magnetic discs of different diameters was positioned on the anterior and posterior aspects of the keloid lesion. The magnets were then encapsulated in acrylic resin to improve retention and adaptation, and the external surface was masked with gold glitter to enhance aesthetics and patient acceptance. The helix-deformity case was treated following a complete digital workflow integration where the sound contralateral ear was digitally scanned, mirror-imaged and then 3D-printed in resin to produce an ear model based on which an anatomically symmetrical pressure device was constructed. Results: All devices were successfully fitted and well tolerated, with no reported discomfort or adverse reactions. The wire spring devices were effective in reducing a large keloids volume; however, frequent reactivation every two weeks was required to ensure continuous pressure application. Incorporating magnets in the customised design allowed controlled and uniform pressure application to small keloid-lesion morphology, with enhanced aesthetics and improved patient acceptance and compliance. The digitally assisted case achieved near-perfect anatomical symmetry with the contralateral ear, reducing operator dependency and fabrication guesswork. Conclusions: Customised pressure therapy devices, of magnetic and spring-based systems, alongside utilising digital technologies, offer effective, non-invasive management for auricular keloids and irregular ear helices as long as the patient is committed to wearing the device. Full article

Objective: The aim of this systematic review was to evaluate the skeletal stability, predictability, and safety of using autogenous iliac crest bone grafts (ICBG) during large maxillary advancement performed with Le Fort I osteotomy. Methods: A systematic literature search was performed in November 2025 using PubMed, Scopus, Embase, Web of Science, and WorldCat databases. Clinical studies reporting large maxillary advancement performed with Le Fort I osteotomy and incorporating ICBG were included. Study selection followed PRISMA guidelines. Data extraction focused on the magnitude of maxillary advancement, surgical protocols, stabilization methods, skeletal stability, relapse patterns, graft integration, implant-related outcomes, and complications. Methodological quality was assessed using the Mixed-Methods Appraisal Tool (MMAT). Results: The review included clinical studies predominantly consisting of case reports, case series, and retrospective cohort studies. ICBG were consistently used in complex clinical scenarios, such as severe maxillary atrophy, hypoplasia, and congenital craniofacial deformities. Large maxillary advancements were generally associated with favorable postoperative skeletal stability, with most relapse occurring during the early healing phase and minimal changes observed during long-term follow-up when rigid fixation and adequate graft integration were achieved. Interpositional grafting facilitated predictable advancement by bridging extensive osteotomy gaps. Donor-site morbidity related to iliac crest harvesting was typically mild and transient. Implant-related outcomes, reported as secondary findings, were generally favorable when implants were placed after an adequate healing period. Conclusions: Despite predominantly observational evidence, ICBG during large maxillary advancement with Le Fort I osteotomy appears to offer predictable advancement, acceptable skeletal stability, and a favorable safety profile, warranting further prospective investigation. Full article

(1) Background: Idiopathic scoliosis is a three-dimensional deformity, yet clinical and research decision-making still relies largely on radiographic Cobb angle measurements. As a radiation-free alternative, clinical assessment of transverse and sagittal plane deformities has gained importance. This study evaluated the concurrent validity and intra- and interrater reproducibility of continuous measurements of rib hump, thoracic kyphosis, and lumbar lordosis obtained using a smartphone application in adolescents with spinal deformities. (2) Methods: Adolescents aged 10–17 years with scoliosis (>10° Cobb) or hyperkyphosis (>50° Cobb) were recruited. Continuous measurements of angle of trunk rotation (ATR) during the Adams forward bend test and in standing position, as well as sagittal profile, were collected using the ISICO app mounted on a standardized plastic tool. Concurrent validity was assessed against a scoliometer using Spearman correlation, root mean square error, and Bland–Altman analysis, while reproducibility was evaluated using intraclass correlation coefficients, standard error of measurement, and minimal detectable change. (3) Results: Thirty-two adolescents were included for validation and intrarater analyses and 34 for interrater analyses. ATR measured during the Adams test showed very high correlation with the scoliometer and minimal bias, while standing ATR showed moderate correlation. Reliability was excellent for rib hump during forward bending and moderate for sagittal parameters, with the lowest values observed for lumbar lordosis. (4) Conclusions: These findings support the clinical use of continuous app-based ATR assessment and suggest that sagittal measurements may be useful with appropriate examiner training. Full article

The extensive cultivation scale of sugar beet seedlings has resulted in the necessity for accurate identification and monitoring of the seedling count, a task which has become crucial and highly challenging in the sugar industry. However, sugar beet seedlings in UAV aerial photography scenarios are mostly small targets with complex backgrounds. Existing general detection models not only have insufficient detection accuracy, but also struggle to balance computational efficiency and resource consumption. To meet the practical needs of field monitoring, this paper proposes the LDH-RTDETR, a sugar beet seedling detection model that balances high accuracy and light weight. This model uses LSNet for feature extraction to reduce size, adds a deformable attention (DAttention) module to capture fine-grained seedling features, and adopts HS-FPN to improve multi-scale feature fusion in the neck network. Experimental results show that the improved model significantly outperforms the original RT-DETR model, with a 3.6% increase in accuracy, a 2.1% increase in mAP50, a recall rate of 86.0%, and a final model size of only 43.3 MB, thus achieving an effective balance between accuracy and model size. This study’s improved model offers an efficient solution for large-area identification and counting of sugar beet seedlings, and is highly significant for advancing the automation of sugar crop field management and agricultural digital transformation. Full article

Arch-suspended structures represent a distinctive form of hybrid suspension system. By combining an arch with a suspended floor system, this structural typology leverages the inherent advantages of both components while mitigating the limitations of each when used independently. This synergy effectively reduces peak internal forces and flexural deformations in structural members. Although widely applied in bridge engineering, research on arch-suspended building structures remains scarce. This paper investigates the construction techniques employed for a large-scale arch-suspended building. The stability of temporary support systems during construction is verified, and the mechanical behavior of critical joints—including the composite slab hanging pillar, arch support, and arch roof—is examined through both experimental testing and numerical simulation. The results demonstrate that a partitioned and segmented construction method is feasible for such complex structures. Structural internal forces and deformations can be effectively controlled by installing tubular temporary supports on both sides of the hanging pillars and lattice temporary supports at the base. Step-by-step unloading of these temporary supports ensures their stability throughout the construction process. Furthermore, the welds in the composite slab hanging pillar effectively transfer tensile forces from the middle plate to the side plates, enabling composite action and collaborative load-bearing among the steel plates. When subjected to loads of 2 times and 4.3 times the design load, localized plasticity was observed in the arch support and arch roof, respectively, while the overall structural integrity remained secure. This study provides a valuable reference for the design and construction of innovative long-span building structures, offering insights that can inform the development and practical application of arch-suspended systems in future architectural projects. Full article

Space-deployable antennas have development requirements of an ultra-large aperture, high stiffness, and multi-frequency multiplexing. To address the challenge of stiffness characterization in the multi-closed-loop complex systems of deployable mechanisms, this paper proposes a parametric stiffness modeling method and a static stiffness model is established, ranging from components and limbs to the overall mechanism. The motion/force mapping model of the deployable mechanism is obtained using screw theory, and the stiffness mapping from joint space to workspace is achieved via the Jacobian matrix. A comprehensive stiffness model of the deployable mechanism incorporating joint effects is established based on the principle of virtual work and the superposition principle of deformations, and its validity is verified through finite element simulation. Building on this, stiffness characteristics based on structural configuration are investigated, and structural forms with excellent stiffness performance are selected through comprehensive evaluation. Six configurations of the deployable mechanism are derived topologically from this structure, and the optimal configuration is selected based on stiffness performance. The parametric stiffness modeling method proposed in this study can effectively characterize the contribution of each component to the overall system stiffness. It lays a theoretical foundation for establishing a quantitative relationship between stiffness performance and configuration, enabling performance-based configuration optimization and dimensional optimization. Full article

Hyperspectral image (HSI) classification faces significant challenges due to the spatial–spectral heterogeneity of land covers and the geometric rigidity of standard convolutions. Although Transformers offer powerful global modeling capabilities, their quadratic computational complexity limits practical efficiency. To address these limitations, this paper proposes a novel hierarchical framework named MDS³-Net (Multiscale Deformable Spectral–Spatial Sequence Network). Specifically, we design a Multiscale Spectral-Deformable Convolution (MSDC) module that adopts a cascaded strategy to sequentially extract discriminative spectral features and adaptively align spatial receptive fields with irregular object boundaries. To capture long-range dependencies efficiently, a Spectral–Spatial Sequence (S³) Encoder is introduced based on a gated large-kernel convolution mechanism, achieving global context modeling with linear complexity. Furthermore, a Dual-Path Feature Extraction (DPFE) module is proposed to perform semantics-preserving dimension reduction via spectral reorganization and spatial attention. Experimental results on four public datasets demonstrate that the proposed MDS³-Net achieves state-of-the-art classification performance and exhibits superior robustness under limited training samples compared to existing methods. Full article

Ionic polymer–metal composites consist of an ion-conducting polymer–gel membrane sandwiched between two flexible electrodes, representing a class of soft electroactive materials capable of large deformation under low voltage. The gel membrane, swollen with solvent, facilitates ion migration under an electric field, enabling actuation. Tailoring the interfacial architecture between the electrode and the polymer–gel membrane is pivotal for advancing high-performance IPMC actuators. This study presents a comparative investigation of three core–shell nanocomposite electrodes, fabricated via in situ polymerization, for IPMC applications. Among these, the polyaniline-coated multi-walled carbon nanotube composite exhibits a deliberately designed hierarchical structure, with a specific surface area of 32.345 m²·g⁻¹ and a conductive doped polyaniline shell, as confirmed through XPS analysis. This optimized interface enables superior charge storage and transport, endowing the corresponding electrode with a specific capacitance of 40.28 mF·cm⁻² at 100 mV·s⁻¹—3.2 times greater than that of conventional silver-based electrodes—along with a reduced sheet resistance. When integrated with a Nafion ion–gel membrane, the PANI@MWCNT electrode achieves a 67% increase in force density and a larger displacement output compared to standard devices, directly correlated with its enhanced electrical and electrochemical properties. This work highlights the critical role of core–shell interfacial engineering in governing electromechanical performance at the electrode–gel interface and offers a practical design strategy for developing high-performance, cost-effective IPMC actuators for soft robotics, flexible electronics, and related applications. Full article

Safety monitoring in container hoisting operations within rail-road intermodal logistics parks is a critical task in industrial safety management. Such scenarios are characterized by complex environments, large variations in target scales, deformable object shapes, and frequent occlusions, which pose significant challenges to visual perception systems. Conventional single-task models suffer from inherent limitations in handling low recall rates for distant small targets and insufficient adaptability to geometric deformations, making them inadequate for high-precision, real-time safety warning applications. To address these challenges, this study proposes a unified visual analysis framework that integrates semantic segmentation and object detection to enhance the recognition performance of small and deformable targets in complex operational environments, enabling real-time perception and safety warning of key objects and hazardous regions within container yards. Specifically, we introduce FSD-YOLO, a fusion-based architecture composed of the following key components. First, a SegFormer-based semantic segmentation module is employed to achieve pixel-level delineation of different operational regions. Second, an improved object detection network is developed based on the YOLOv8n architecture, incorporating: (1) the integration of C2f modules in the shallow layers of the backbone to enhance high-resolution feature extraction; (2) the embedding of C2fDCN modules within the detection head to improve modeling capability for deformable objects via deformable convolution; (3) the adoption of CARAFE upsampling operators to optimize multi-scale feature fusion; and (4) a dynamic loss-weighting strategy for small objects, where loss weights are adaptively adjusted according to target area to increase training emphasis on small-scale targets. Finally, a decision-level fusion strategy is applied to combine segmentation and detection outputs, enabling real-time safety judgment based on semantic rules. Experimental results on a self-constructed container yard dataset demonstrate that the proposed detection model achieves an mAP50-95 of 0.6433 and an mAP50 of 0.9565, significantly outperforming the baseline YOLOv8n model (mAP50-95: 0.5394, mAP50: 0.8435), thereby validating the effectiveness of the proposed framework. Full article

In order to design a new type of long-life and reliable casing hanger, this paper studied the failure mechanisms of the rubber sealing structures of the slip hanger and the mandrel hanger. Through tensile and compressive tests, the tests and analyses of different rubber structures were completed, data fitting was carried out, and the constitutive relationship of the rubber material was obtained. A superior constitutive model was applied to the sealing materials of the hanger. Numerical calculations were used to obtain the strength and sealing performance variation laws of the rubber sealing components with different structures, and the reasons for the failure of the conventional hanger were found. The results show that the rubber components and the ball-shaped metal sealing components will lose their elastic deformation under high-pressure and large-load conditions, and the reliability will decrease. Finally, a new type of metal sealing structure was designed. Compared with the previous metal sealing structures, this paper conducts a more in-depth and detailed study, and further presents the superiority of metal sealing in terms of structural dimensions and working principles. Experiments were conducted, and the results showed that this sealing structure can meet the usage requirements of the casing hanger with large loads and high pressure. The research results provide theoretical and application guidance for the design of long-life and reliable performance hanger sealing structures. Full article

Future contributions to sea level rise from the Antarctic Ice Sheet due to climate change remain one of the largest uncertainties for future sea level. Improving predictions of ice mass loss is a major goal of numerical ice sheet models, but a major difficulty is that ice sheet models assume an empirical fit to modern-day observed speeds to infer sliding parameters. While this results in accurate modern-day comparisons, predictions for future or past climates that have substantially different conditions will be inaccurate if the empirical sliding law used is not appropriate. To help constrain which basal physics is most appropriate and therefore which basal parameterizations should be used in ice sheet models, here, we pursue an understanding of which physical mechanisms are most likely to explain the spatial variability in flowline speeds throughout the Antarctic Ice Sheet. Specifically, we compare observed flowline surface speeds with predictions of speeds from internal ice deformation and Weertman sliding using a conservative range of physical parameters. Despite large uncertainties, we find a number of flowlines where the predictions can be distinguished from each other and one can infer that one of the two mechanisms, or a third mechanism, Coulomb frictional failure, may likely be principally responsible. Geographic patterns in the dominant mechanism are observed. Weertman sliding appears dominant in several flowline clusters in East Antarctica, and there are regional consistencies in the estimated nearness to flotation at locations of inferred initiation of Coulomb failure. Weertman sliding at faster rates is also observed within regions of inferred Coulomb failure, consistent with theoretical expectations. The key finding that the dominant deformation mechanism varies along and between Antarctic flowlines may complicate how ice sheet models need to be parameterized if accurate predictions of future ice loss and sea level rise are to be accurate. Full article

The advancement of sustainable construction requires the development of earthen materials compatible with 3D printing (additive manufacturing), along with specified engineering standards. Many existing studies improve workability and early strength using chemical stabilizers such as cement; however, these additives increase embodied carbon and undermine sustainability objectives. Challenges remain in the formulation of an earthen mixture that satisfies both printability and structural requirements for large-scale construction. Previous earth-based mixes have reported excessive shrinkage and inadequate compressive strength. This study presents the systematic optimization of a low-carbon, 3D-printable earthen mixture using locally sourced clay-loam soil from Belén, New Mexico (NM). The soil was modified with graded concrete sand and rice hull fiber to improve printing parameters such as buildability, extrudability, and printability while meeting the NM Earthen Building Code requirements for compressive and flexural strength. Soil characterization tests (particle size distribution, consistency, optimal water content) guided iterative refinement to enhance dimensional stability and mechanical performance. A baseline 2:1 soil-to-sand ratio (max aggregate size No. 4) was established. Incorporating $2\%$ rice hull fiber and reducing max aggregate size to No. 16 (S67F2) early-age shrinkage was reduced from $12.33\%$ to $3.48\%$ ($72\%$ reduction) while maintaining a 28-day compressive strength exceeding 660 psi, more than twice the code minimum. The optimized mixture supported 24 printed layers without deformation, achieved 189 psi flexural strength (three times the code minimum), and produced a stable 2-ft-diameter dome with minimal cracking. Full article

Rotator cuff suture anchors have traditionally been inserted at the 45° “deadman” angle, but this recommendation was largely derived from single-row constructs and may not reflect the biomechanics of contemporary double-row suture bridge repairs. This study compared the biomechanical performance and stress distribution of medial row anchors inserted at 45° versus 90° in a double-row suture bridge construct. Sixteen ovine humeri with intact infraspinatus tendons were randomized to 45° or 90° medial anchor insertion (n = 8 each), and double-row suture bridge repair was performed using 3.5 mm metallic and PEEK anchors. Specimens underwent uniaxial tensile testing (10-N preload, 5 mm/min) to failure, measuring yield load, failure load, displacement, stiffness, and energy absorption; additionally, a CT-based finite element model of the human humerus assessed von Mises stress, strain, and deformation under 200 N loading. Mean failure load was 161.96 ± 50.99 N for 45° and 185.61 ± 60.97 N for 90° (p = 0.447), and stiffness was 31.63 ± 8.18 N/mm versus 36.79 ± 9.26 N/mm (p = 0.291). Displacement at failure was greater with 90° insertion (8.11 ± 0.51 mm vs. 6.65 ± 0.83 mm; p = 0.002), while energy absorption was higher but not significantly different (p = 0.255). Finite element analysis demonstrated lower bone von Mises stress with 90° insertion (14.03 MPa) compared with 45° (24.77 MPa), with similar deformation. In double-row suture bridge repair, 90° medial anchor insertion provides comparable fixation strength to that at 45° while reducing bone stress, suggesting a biomechanical advantage. Full article

Active support systems are being increasingly applied in the control of large deformation in soft rock tunnels, and exploring the bearing characteristics of prestressed anchor bolts is of great engineering value for improving the long-term stability of tunnel structures. To address the problems of insufficient quantitative characterization of the bearing performance of prestressed anchor bolt support in soft rock tunnels and the difficulty of small-scale model tests in revealing the synergistic bearing law of support and surrounding rock, this study took a 350 km/h double-line high-speed railway tunnel as the prototype and established a large-scale tunnel structure model test system to conduct comparative tests under three working conditions: unsupported, ordinary bolt support, and prestressed anchor bolt support. By monitoring the tunnel failure process and mechanical response of the support structure throughout the test, the failure modes, bearing capacity, deformation characteristics, and axial force distribution of anchor bolts of tunnels under different support forms were systematically analyzed to quantitatively reveal the active support mechanism and bearing strengthening effect of prestressed anchor bolts. The results show that the design bearing capacity of the tunnel model with prestressed anchor bolt support is increased by 127.3% and 31.6% compared with that of the unsupported and ordinary bolt support models, and the ultimate bearing capacity is increased by 120.0% and 43.5%, respectively. Its secant stiffness in the initial loading stage reaches 80.0 kPa/mm, which is five times that of the ordinary bolt support and can effectively restrain the early plastic deformation of the surrounding rock. When the design bearing capacity is reached, the tensile stress of prestressed anchor bolts accounts for 40.2~69.8% of the ultimate tensile strength, with a more uniform axial force distribution and a much higher utilization rate of material mechanical properties than ordinary anchor bolts, which can fully mobilize the bearing potential of deep rock mass and realize the synergistic bearing of support and surrounding rock. This study accurately quantifies the bearing strengthening law of prestressed anchor bolts on tunnel support systems and clarifies the core mechanism of their active support. The research results provide important experimental basis and theoretical reference for the optimal design and engineering application of prestressed anchor bolts in soft rock tunnel engineering. Full article