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关键词： developable surface segmentation   CAD models   sparse normal discontinuity   dihedral angle  

摘要： Segmenting CAD models into developable surface patches is a fundamental problem in geometric modeling and manufacturing-oriented applications. Existing approaches often rely on discrete Gaussian curvature estimation or Gauss map analysis;however, their performance on CAD meshes is frequently hindered by numerical instability, sensitivity to mesh tessellation, and complex parameter tuning. In this work, we propose a simple and robust method for developable surface segmentation based on a sparse normal discontinuity prior. Our key observation is that industrial CAD models are typically composed of large developable regions separated by a sparse set of sharp creases and edges. Consequently, segmentation boundaries correspond to sparse discontinuities in the surface normal field rather than continuous variations in curvature. Based on this perspective, we formulate developable surface segmentation as the detection of sparse normal jump discontinuities. In the discrete setting of triangle meshes, this formulation naturally leads to a dihedral angle-based approach that avoids explicit curvature estimation and admits an efficient graph-based solution. The proposed algorithm consists of face normal computation, dihedral angle-based boundary detection, and connected component extraction on a thresholded face adjacency graph. The method requires only a single geometrically interpretable parameter and naturally aligns segmentation boundaries with sharp features commonly found in CAD models. Experimental results on a diverse set of industrial CAD meshes, including standard benchmarks widely used in related research, demonstrate that the proposed approach achieves robust and accurate segmentation, as validated by both visual coherence and quantitative developability metrics.

关键词： deep learning   diabetic retinopathy   fundus imaging   Grad-CAM   image classification  

摘要： Introduction Diabetic retinopathy (DR) is a leading cause of vision impairment among individuals with diabetes. Early detection and accurate grading are essential for timely clinical management. However, developing robust models for automated interpretation and grading of fundus images remains challenging due to variability in lesion appearance and image *** This study proposes a deep learning framework for DR classification from fundus images based on a DenseNet121 backbone initialized with CheXNet weights. A Convolutional Block Attention Module (CBAM) is integrated to enhance feature representation through channel and spatial attention mechanisms in a data-driven manner. In addition, Gradient-weighted Class Activation Mapping (Grad-CAM) is employed to provide post hoc visual explanations of model predictions. The proposed CheXNet_CBAM model is evaluated against several convolutional neural network architectures, including CheXNet, DenseNet121, MobileNetV2, VGG19, and ResNet50, using the APTOS 2019 and DDR *** On the APTOS 2019 dataset, the proposed model achieves an accuracy of 96.12%, while on the DDR dataset it attains 96.33%, outperforming the compared architectures on both *** The results indicate that incorporating CBAM improves discriminative feature learning within a DenseNet121-based framework. While the model demonstrates strong performance across two public datasets, further prospective evaluation and external validation are required to assess its clinical applicability in real-world settings.

关键词： Accuracy assessment, Validation   Computer-Aided Manufacturing   Mandibular reconstruction, Computer-Aided Design   Prosthesis  

摘要： The lack of a standardized methodology complicates accuracy assessment in computer-assisted mandibular reconstruction. Existing landmark-based methods are susceptible to operator variability, while surface-based comparisons can mask local deviations. This study validates a novel, automated protocol, the Global Positioning Layout (GPL), to quantify the 3D discrepancy between the virtual surgical plan and the postoperative outcome, by comparing its performance and reliability against Methods A and B. A retrospective cohort of 17 patients was analysed, with three operators performing all measurements on two occasions. The GPL method demonstrated complete reproducibility, with no inter- or intra-operator variability, providing a detailed, spatially-oriented assessment of deviations. In contrast, the landmark-based method showed poor reproducibility and systematic bias and was often inapplicable due to the absence of landmarks after resection. The surface-based method, while objective for its mean error metric, was operator-dependent for initial alignment and its non-directional output masked significant localized deviations. This study validates GPL as a robust and fully reproducible tool that overcomes the critical limitations of established techniques. The GPL method provides a strong foundation for a standardized protocol, essential for the reliable comparison of surgical outcomes, refinement of surgical techniques, and improvement of long-term patient outcomes.

关键词： Alpha angle   femoroacetabular impingement   hip arthroscopy   patient-reported outcomes   posterolateral cam lesion  

摘要： Background: Femoroacetabular impingement syndrome (FAIS) is a common hip disorder that can lead to joint degeneration and osteoarthritis. Posterolateral (PL) cam lesions, characterised by an alpha angle >60 degrees on anteroposterior (AP) pelvis and Dunn views, present significant surgical challenges due to their anatomical location and proximity to critical vascular structures. Effective surgical intervention relies on achieving optimal postoperative resection, yet clear radiographic thresholds for surgical success remain undefined. Objective: This study aimed to investigate the relationship between postoperative alpha angle measurements on pelvis AP radiographs and clinical outcomes in patients undergoing hip arthroscopy for PL cam lesions. Additionally, it seeks to determine an optimal postoperative alpha angle threshold that correlates with improved patient-reported outcomes at 2 years. Methods: A retrospective analysis was performed on a cohort of 117 patients (121 hips) who underwent hip arthroscopy for femoroacetabular impingement syndrome (FAIS) between the years 2013 and 2022, with a minimum follow-up period of 2 years. Preoperative and postoperative alpha angles were measured on the pelvis AP and Dunn views. Clinical outcomes were assessed using the Hip Outcome Score-Activities of Daily Living (HOS-ADL), the modified Harris Hip Score (mHHS), and the Non-Arthritic Hip Score (NAHS). Receiver operating characteristic (ROC) curve analysis was used to establish an alpha angle cutoff associated with better functional recovery. Results: Patients with a postoperative alpha angle below 55 degrees demonstrated significantly better functional outcomes across all scoring systems. ROC analysis confirmed that alpha < 55 degrees was a strong predictor of achieving a patient-acceptable symptomatic state (PASS), with an area under the curve (AUC) of 0.849 for mHHS, 0.741 for NAHS, and 0.721 for HOS-ADL (p < 0.001). Sensitivity and specificity values varied across scoring s

关键词： 3D printing   Bone cement   Antibiotics   Porogen   CAD   Infection management   Customized drug delivery   Osteomyelitis   Prosthetic joint infection  

摘要： IntroductionPolymethylmethacrylate (PMMA) antibiotic beads are widely used in orthopedic surgery for localized infection control, but inconsistent drug elution can limit efficacy. Three-dimensional (3D) printing offers a way to create implants with controlled architectures, enabling more predictable and customizable drug release. This study explores the use of internal structural variation to influence the elution profiles of vancomycin and tetracycline and assess their antibacterial *** specimens were 3D printed using a commercial resin mixed with 2% vancomycin or tetracycline. To evaluate the effects of composition and structure, additives such as sodium chloride (NaCl) and polyvinylpyrrolidone (PVP) were included, and four internal architectures-solid, hollow, large honeycomb, and small honeycomb-were tested. Elution was assessed over 7 days, and antibacterial activity was tested against S. epidermidis and E. coli using agar *** exhibited greater cumulative release than vancomycin, likely due to solubility and molecular weight differences. Honeycomb structures, especially the smaller variant, produced the most sustained and consistent elution profiles. NaCl decreased vancomycin but increased tetracycline release, while PVP enhanced release for both. All formulations showed antibacterial ***3D printing enables the design of antibiotic-eluting implants with tailored release profiles. The honeycomb architecture is especially promising for sustained delivery. Further in vivo studies are needed to confirm clinical relevance and optimize formulations for orthopedic use.

关键词： angiography   percutaneous coronary intervention   prerandomization treatment plan   quantitative flow ratio   CAD   coronary artery disease   FFR   fractional flow reserve   iFR   instantaneous wave-free ratio   LCx   left circumflex coronary artery   MACE   major adverse cardiac event(s)   PCI   percutaneous coronary intervention   QFR   quantitative flow ratio   RCA   right coronary artery   SMD   standardized mean difference  

摘要： The optimization of a treatment plan developed on the basis of coronary angiography alone is recognized as one of the underlying rationales for the clinical benefits of physiology-guided percutaneous coronary intervention (PCI).

关键词： Bleach shades   CAD/CAM ceramics   CIEDE2000   Ceramic discs   Color thresholds   Spectrophotometer   Translucency   Try-in pastes  

摘要： This study evaluated the optical influence of try-in media (distilled water, glycerin, and commercial try-in pastes) on ultrathin (0.5-mm) CAD/CAM bleach-shade ceramic discs, focusing on CIEDE2000 color difference (ΔE₀₀), translucency parameter (TP₀₀; ΔE₀₀ between white- and black-backed measurements), and device-reported shade outputs across different ceramic systems. Forty-four 0.5-mm CAD/CAM ceramic discs were fabricated from Celtra Duo (BL2-LT, BL3-LT), VITA Suprinity (0M1-HT), and VITA Enamic (0M1-HT). Each specimen was measured over standardized white and black backgrounds using distilled water, glycerin, eight commercial try-in pastes, or no medium (control). Lab* values and VITA Classic/3D-Master shade outputs were recorded with a dental spectrophotometer under D65/2° conditions; a custom jig standardized specimen positioning and probe angulation. Repeated measurements (n = 5) were analyzed using linear mixed-effects models. Clinical interpretation used ΔE₀₀ perceptibility/acceptability (≈ 0.8/1.8) and translucency thresholds (TPT₀₀=0.62; TAT₀₀=2.62). Relative to the no-media condition, both water and glycerin produced large, clinically perceptible color shifts across all ceramics (mean ΔE₀₀ ≈ 3.2–5.6; p < 0.001), while direct water–glycerin differences were smaller (≈ 0.7–1.6). Translucency responses were material dependent: Celtra groups showed minimal ΔTP₀₀ relative to glycerin (typically |ΔTP₀₀| ≤ ~0.3), Suprinity showed a modest reduction ( ≈ − 1 to − 2), and Enamic exhibited pronounced translucency loss ( ≈ − 5 to − 7), frequently exceeding translucency acceptability (|ΔTP₀₀| ≥ 2.62). Only selected Celtra BL2/BL3 conditions with translucent/light try-in pastes approached ΔE₀₀ acceptability (≤ 1.8) on white backgrounds. Device-reported shade agreement sometimes masked clinically unacceptable differences: 11% of 3D-Master “matches” and 28% of Classic “matches” still corresponded to ΔE₀₀ > 1.8, particularly over black backgrounds. Try-in media are n

关键词： bladeless wind turbine   vortex-induced vibrations   mechanical rectification   cylindrical cam mechanism   urban wind energy   computational fluid dynamics   finite element analysis  

摘要： Global efforts to mitigate climate change and reduce reliance on fossil fuels have intensified interest in sustainable, urban-compatible wind energy technologies. Conventional wind turbines, however, remain limited in densely populated environments due to acoustic emissions, mechanical complexity, cost, and risks to avian wildlife. This study proposes and numerically evaluates a bladeless wind turbine concept based on vortex-induced vibrations (VIVs) as a simplified alternative to conventional bladed systems. The proposed design replaces rotating blades with a vertical mast that undergoes wind-induced oscillations, which are passively converted into unidirectional rotational motion using a cylindrical cam (CCAM) mechanism. The aerodynamic behavior and structural response of the system are investigated using computational fluid dynamics (CFD) and finite element analysis (FEA) under low-wind-speed conditions representative of urban environments. The numerical results indicate well-defined flow separation and wake formation conducive to VIV, along with low stress and displacement levels in the mast, supporting reliable mechanical engagement with the CCAM mechanism. These findings demonstrate the feasibility of mechanically rectified VIV-based bladeless wind turbines and highlight their potential as low-noise, low-impact solutions for decentralized and urban wind energy applications.

关键词： Shear bond strength   Orthodontic brackets   CAD/CAM ceramics   Surface treatment   Lithium disilicate   Feldspathic porcelain  

摘要： ObjectivesThis study evaluated the shear bond strength (SBS) of two types of orthodontic brackets (ceramic and metal) bonded to two CAD/CAM ceramic materials (feldspathic ceramic and lithium disilicate glass-ceramic), each subjected to different surface treatments, and assessed adhesive remnant index (ARI) *** and methodsSixty-four ceramic discs (1 mm thick;n = 32 per material) were prepared. Surface pretreatments were alumina air abrasion followed by phosphoric acid etching or hydrofluoric acid etching. Each subgroup was bonded with metal or ceramic brackets using a light-cured adhesive. SBS was measured with a universal testing machine, and ARI was assessed under a stereomicroscope. Three-way ANOVA tested the effects of ceramic type, bracket type, and surface treatment (alpha = 0.05), and chi-square tests compared ARI *** results demonstrated that the ceramic type significantly influenced SBS (p = 0.004). Lithium disilicate glass-ceramic exhibited higher SBS values than feldspathic ceramic. Bracket type also had a significant effect on SBS, regardless of ceramic type or surface treatment (p = 0.001). However, the applied surface treatments did not produce a significant difference in SBS (p = 0.546);phosphoric acid etching after alumina air abrasion yielded comparable results to hydrofluoric acid etching. ARI scores did not differ significantly among groups, and debonded surfaces showed no gross ceramic damage under *** type and bracket type significantly affected SBS, whereas surface pretreatment did not under the tested *** relevanceBalancing adequate bracket retention with safe debonding is essential for ceramic restorations. Comparable SBS between the two pretreatments and the absence of visible ceramic damage support conservative, clinically oriented conditioning protocols.

关键词： Large language models   Coronary Stenosis   Coronary computed tomography angiography   Plaque burden   Management  

摘要： ObjectivesTo evaluate the performance of large language models (LLMs), including retrieval-augmented generation (RAG)-based approaches, in extracting components and management recommendations from structured coronary computed tomography angiography (CCTA) reports according to the Coronary Artery Disease Reporting and Data System (CAD-RADS 2.0). Materials and methodsA total of 320 fully structured CCTA reports were analyzed using LLM. Closed-source standard ChatGPT-5, NotebookLM (RAG-based model), and a RAG-adapted ChatGPT-5 model (ChatGPT-5-RAG) were used. Each model extracted the CAD-RADS category, plaque burden, presence of high-risk plaque (HRP), other modifiers, full score, and management recommendations in accordance with the CAD-RADS 2.0 guidelines. We compared LLM outputs with reference standards determined by two expert cardiovascular radiologists. ResultsChatGPT-5-RAG showed the highest accuracy for CAD-RADS classification (0.959, 95% CI: 0.932-0.976), plaque burden (0.912, 95% CI: 0.876-0.939), HRP detection (0.988, 95% CI: 0.968-0.995), other modifiers (0.950, 95% CI: 0.920-0.969), and full score (0.828, 95% CI: 0.783-0.866). Closed-source ChatGPT-5 showed the weakest performance across all components. Significant statistical differences were found among the three models (p < 0.001). Management recommendations were qualitatively rated on a three-point Likert scale;although agreement between models was low, ChatGPT-5-RAG and NotebookLM performed almost perfectly (median 3 points). ConclusionThis study demonstrates that RAG-enhanced LLMs significantly improve accuracy and reliability in extracting CAD-RADS 2.0 components and generating clinical management recommendations. The findings highlight the potential of RAG-based LLMs as innovative, explainable tools for automated and standardized CCTA reporting in clinical radiology workflows.