Search Results (218)

Background: This preliminary case series aimed to evaluate the clinical and morphometric outcomes of maxillomandibular advancement (MMA) surgery in patients with severe obstructive sleep apnea (OSA) using virtual surgical planning (VSP), patient-specific cutting guides, and customized titanium plates. Primary outcomes included changes in the Apnea–Hypopnea Index (AHI), airway dimensions, surgical accuracy, and quality of life. Methods: In this preliminary case series, six patients with severe OSA underwent MMA surgery planned using three-dimensional VSP, and executed with the aid of CAD-/CAM-generated surgical guides and patient-specific osteosynthesis. Clinical variables included AHI, Epworth Sleepiness Scale (ESS), and computed tomography-based airway morphometry. Surgical accuracy was assessed by comparing planned and achieved skeletal movements. Statistical analysis was performed using Wilcoxon signed-rank tests and Spearman’s correlation. Results: The mean preoperative AHI decreased significantly from 48.8 ± 23.6 to 12.4 ± 10.0 (p = 0.035), and ESS scores improved from 14.5 ± 4.6 to 7.8 ± 2.1 (p = 0.029). Mean airway area increased significantly from 51.8 ± 9.0 mm² to 91.8 ± 26.6 mm² (p = 0.035). A strong but non-significant correlation was observed between airway gain and ESS improvement (p = 0.754, p = 0.084). No patients required CPAP at 6-month follow-up, and all were asymptomatic. The anteroposterior accuracy of skeletal movements was high: 82.6% for the maxilla and 85.8% for the pogonion, with mean absolute errors of 1.25 mm and 1.95 mm, respectively. Vertical accuracy was lower, particularly in the chin region, where error analysis showed greater variability. No statistically significant differences were found between planned and achieved movements in any vector. Conclusions: MMA surgery performed with VSP, cutting guides, and customized titanium plates offers a highly effective, safe, and precise treatment modality for selected OSA patients. This approach leads to a significant reduction in AHI, expansion of the upper airway, and improvement in patient-reported daytime functioning. High accuracy in skeletal repositioning—particularly in anteroposterior vectors—supports the reliability and reproducibility of digitally guided orthognathic surgery. These findings reinforce the role of technologically assisted MMA as a definitive treatment for severe OSA. Full article

To address the challenges of complex backgrounds, varying target scales, and dense targets in license plate detection within surveillance scenarios, we propose an enhanced method based on an improved YOLOv8n network. This approach involves redesigning key components of the YOLOv8n architecture, including the C2f module, the SPPF module, and the detection head. Additionally, we optimize the WIoU loss function, replacing the original CIoU loss function, which leads to improved bounding box feature extraction and enhanced regression accuracy. To evaluate the model’s robustness in complex environments with varying lighting, backgrounds, angles, and vehicle types, we created a custom surveillance license plate dataset. Experimental results show that the improved model achieves a notable increase in detection accuracy, with mAP@0.5 rising from 90.9% in the baseline model to 94.4%, precision improving from 90.2% to 92.8%, and recall increasing from 82.9% to 87.9%. Additionally, the model’s parameters are reduced from 3.1 M to 2.1 M, significantly enhancing computational efficiency. Moreover, the model achieves an inference speed FPS of 86, maintaining high precision and meeting real-time detection requirements. This demonstrates that our method provides an efficient and reliable solution for license plate detection in surveillance scenarios. Full article

A novel design of a proton exchange membrane electrolyzer is presented. In contrast to previous designs, the flow field plates are round and oriented horizontally with the feed water entering from a central hole and spreading evenly outward over the anode flow field in radial, interdigitated flow channels. The cathode flow field consists of a spiral channel with an outlet hole near the outside of the bipolar plate. This results in anode and cathode flow channels that run perpendicular to avoid shear stresses. The novel sealing concept requires only o-rings, which press against the electrolyte membrane and are countered by circular gaskets that are placed over the flow channels to prevent the membrane from penetrating the channels, which makes for a much more economical sealing concept compared to prior designs using custom-made gaskets. Hydrogen leaves the electrolyzer through a vertical outward pipe placed off-center on top of the electrolyzer. The electrolyzer stack is housed in a cylinder to capture the oxygen and water vapor, which is then guided into a heat exchanger section, located underneath the electrolyzer partition. The function of the heat exchanger is to preheat the incoming fresh water and condense the escape water, thus improving the efficiency. It also serves as internal phase separator in that a level sensor controls the water level and triggers a recirculation pump for the condensate, while the oxygen outlet is located above the water level and can be connected to a vacuum pump to allow for electrolyzer operation at sub-ambient pressure to further increase efficiency and/or reduce the iridium loading. Full article

Objective: Frontal sinus surgery is still challenging for surgeons; the frontal osteotomy with the preparation of a frontal bone flap to access the sinus is usually hand-crafted by experienced surgeons. The objective of our study is to present a fully digital protocol for the manufacturing of “in-house” surgical cutting guides, customized to the patient’s anatomy, to perform precise frontal sinus osteotomy, showing the costs, times, and intraoperative complications reduction. Materials and Methods: A prospective study was conducted on 12 patients with complex pathologies involving the frontal sinus who underwent frontal sinus osteotomy in the Maxillofacial Surgery Unit of the Federico II University of Naples, from January 2021 to April 2025, considering the last surgery in November 2023. The same digital protocol to manufacture the surgical cutting guide was used for all the 12 patients. The first step was to upload the preoperative CT images in DICOM format to the software Mimics Medical to perform a rapid segmentation of the skull region of interest to create a 3D object and to identify the frontal sinus margins and the osteotomy lines. The second step was to realize the surgical cutting guide, incorporating the design of titanium plates to fix onto the skull in order to make a precise osteotomy. The final digital step was to export the cutting guide 3D object in the software “Formlab-Form 3B” to print the model with a specific resin. The model was then used during the surgery to perform the precise frontal osteotomy by piezo surgery. The clinical outcomes, in terms of complications and recurrences, were then recorded. Results: In all the patients, no intraoperative complications occurred; the median follow-up was 31.7 months and at one year of follow-up only one patient experienced a recurrence. The mean operative time was about 4 h, with a frontal osteotomy time of about 23 min. Digital protocol time was about 4 h while printing times were between 2 and 4 h. Conclusions: This “in-house” protocol seems to demonstrate that the use of intraoperative templates for the realization of the frontal sinus osteotomy reduces preoperative and intraoperative costs and times, reducing the risk of intraoperative complications, and also allows less experienced surgeons to perform the procedure safely. Obviously, this study is to be considered a “pilot study”, and other studies with large cohorts of patients will have to confirm these promising results. Full article

The purpose of this study was to evaluate the bactericidal effect of 270 nm UV-C light-emitting diode (LED) light delivered through a newly designed prototype device with thin optical fiber against Enterococcus faecalis (E. faecalis). The prototype device, developed to integrate UV-C light into a thin optic fiber (diameter 124 µm) connected to a UV-C LED (Luminous Device; Sunnyvale, CA, USA) via a specialized double-lens system that focuses divergent light to achieve a 65 mm working distance and a numerical aperture of 0.22. E. faecalis, was cultured at 37 °C under aerobic conditions for 24 h. The UV-C LED optical fiber was positioned 10 mm above the bacterial culture prepared in the wells of a 96-well plate. The E. faecalis cells were exposed to UV-C irradiation for 0, 10, 30, 60, 90, 120 and 180 s. Following irradiation, the OD600 values were measured after incubation at 37 °C for an additional 24 h. The data were statistically analyzed using one-way ANOVA, followed by Tukey’s honestly significant difference (HSD) test at a significance level of 0.05. UV irradiation at 270 nm significantly reduced E. faecalis growth in a time-dependent manner (p < 0.05). No significant changes were observed at 0 and 10 s, while peak reductions occurred at 120 and 180 s, with effects beginning at 30 s and increasing over time. The 270 nm UV-C wavelength was highly effective in bactericidal action against E. faecalis. The custom-designed UV-C delivery system effectively integrated the light source into a thin optical fiber, allowing for efficient UV-C light transmission and demonstrating its potential for application in narrow spaces such as root canals. Full article

Additive manufacturing (AM) technologies have witnessed remarkable advancements, offering opportunities to produce complex components across various industries. This paper explores the potential of AM for fabricating bipolar plates (BPPs) in fuel cell or electrolysis cell applications. BPPs play a critical role in the performance and efficiency of such cells, and conventional manufacturing methods often face limitations, particularly concerning the complexity and customization of geometries. The focus here lies in two specific AM methods: the laser powder bed fusion of metals (PBF-LB/M) and material extrusion of metals (MEX/M). PBF-LB/M, tailored for high-performance applications, enables the creation of highly complex geometries, albeit at increased costs. On the other hand, MEX/M excels in rapid prototyping, facilitating the swift production of diverse geometries for real-world testing. This approach can facilitate the evaluation of geometries suitable for mass production via sinter-based manufacturing processes. The geometric deviations of different BPPs were identified by evaluating 3D scans. The PBF-LB/M method is more suitable for small features, while the MEX/M method has lower deviations for geometrically less complex BPPs. Through this investigation, the limits of the capabilities of these AM methods became clear, knowledge that can potentially enhance the design and production of BPPs, revolutionizing the energy conversion and storage landscape and contributing to the design of additive manufacturing technologies. Full article

Accurate inversion of geotechnical parameters is essential for assessing foundation-bearing capacity and stability, which directly impact structural safety and serviceability. Accurate prediction of load settlement behavior is crucial to prevent overdesign and underperformance, ensuring that foundations support anticipated loads without excessive deformation or failure. This paper presents an integrated optimization system combining ABAQUS (2022), Python (PyCharm21.3.3), and MATLAB (2022b) software, based on the Duncan–Chang (DC) model, for inversion of key geotechnical parameters. The ABAQUS UMAT subroutine customizes the DC model, facilitating its application in finite element simulations for soil–structure interaction analysis. To improve the optimization process, an adaptive genetic algorithm that dynamically adjusts crossover and mutation rates, thereby improving solution searches and parameter space exploration, is implemented. Key parameters of the DC model—the initial tangent stiffness (K) and nonlinear deformation characteristics (n) of soil—are inverted. The accuracy of this inversion is validated through comparisons with experimental pressure–settlement curves obtained from indoor bearing plate tests. Therefore, this optimization system effectively integrates intelligent algorithms with finite element analysis, serving as a reliable tool for precise geotechnical parameter inversion, with potential for improving foundation design accuracy, optimizing soil–structure interaction predictions, and improving the overall stability and safety of geotechnical structures. Full article

This study introduces a novel, low-cost, non-contact measurement system for heat flux estimation based on an enhanced thermometric method. The customized system was designed and assembled to implement a non-contact, indirect approach for heat flux assessment. Developed as an affordable alternative to conventional contact-based techniques, it is suitable for historical buildings, where invasive sensors could compromise structural integrity. The system integrates real-time data acquisition, remote access via a web-based interface, and automated data processing, enhancing both usability and efficiency. Laboratory tests were conducted to evaluate its performance, with results compared against data from widely used heat flow plates and air/surface temperature sensors. The results showed good agreement between the proposed method and the reference data. Small differences were observed between the values measured by the air temperature sensors (0.10 °C on average), as well as by the contact and non-contact surface temperature sensors (0.12 °C on average). Finally, percentage variations between −6% and −5% in terms of heat fluxes confirmed the reliability of the non-contact approach. These findings provide a strong foundation for further testing, including applications in real buildings. Full article

Backpacks play a pivotal role in facilitating the transportation of essential items, particularly within the realm of physical activities. In demanding physical environments such as mountain sports, effective thermoregulation, pressure absorption, and distribution become paramount due to the repetitive interaction between the athlete’s back and the corresponding area of the backpack. Given that the backpack pads serve as a crucial component of this system, acting as the intermediary layer between the human body and the backpack itself, this study delves into the mechanical and thermoregulatory properties of these components. Specifically, it compares a commercially available pad configuration with five lattice structures manufactured using additive manufacturing techniques. These methods include Large-Volume Filament printing, Multi-Jet Fusion, High-Speed Laser Sintering, and Laser Sintering, with an additional post-processing step—smoothening—for the Multi-Jet Fusion pads. All pads are evaluated on both standardized test protocols regarding mechanics, surface roughness, and humidity as well as a biomechanical setup. For continuous measurement during biomechanical testing, a sensor system including pressure, humidity, and temperature sensors is developed. In addition, a thermal camera was used to measure surface temperature at the back. Throughout the biomechanical testing, 20 male athletes performed a 15 min treadmill walk at 5 km/h and an incline of 6° with all pad configurations, wearing a commercially available backpack with an additional 8 kg of mass. The results revealed significant preferences regarding temperature and humidity uptake, backed up by the standardized test procedures. Furthermore, investigations with the customized sensor system show the irrelevance of the damping-improved back plate design. Overall, additively manufactured backpack pads can play a pivotal role in the thermoregulation and personalized design of backpack configurations. Full article

Design standards for manual handling equipment tend to measure maximal loads and moving forces using a smooth, flat, horizontal steel plate; yet, in everyday use, such equipment is used on floor coverings. Such test methods therefore overestimate the maximal loads acceptable for operators, which increases the risk of injury including the development of musculoskeletal disorders. This study presents a new approach for calculating the pushing force for manually handled equipment moving longitudinally on resilient floor coverings from the pushing force measured on a steel plate. This method combines corrective forces with the pushing force model presented in this study. Corrective force abaci, which describe corrective forces as functions of the hardness of the floor covering’s base foam, are provided for each type of tread and bearing in the cart’s wheels. These abaci have been elaborated from pushing force measurements obtained with 44 wheel designs (of varying diameters, treads and bearings) tested on five different floors on a custom-built test bench. A mean deviation between experimental results and model predictions of 5.1% is obtained for pushing forces. These results permit us to account for the real conditions in which manual handling equipment is used and help in reducing the incidence of musculoskeletal disorders. Full article

In elevator systems, pressure plates secure guide rails and limit displacement, but defects compromise their performance under stress. Current detection algorithms face challenges in achieving high localization accuracy and computational efficiency when detecting small defects in guide rail pressure plates. To overcome these limitations, this paper proposes a lightweight defect detection network (LGR-Net) for guide rail pressure plates based on the YOLOv8n algorithm. To solve the problem of excessive model parameters in the original algorithm, we enhance the baseline model’s backbone network by incorporating the lightweight MobileNetV3 and optimize the neck network using the Ghost convolution module (GhostConv). To improve the localization accuracy for small defects, we add a high-resolution small object detection layer (P2 layer) and integrate the Convolutional Block Attention Module (CBAM) to construct a four-scale feature fusion network. This study employs various data augmentation methods to construct a custom dataset for guide rail pressure plate defect detection. The experimental results show that LGR-Net outperforms other YOLO-series models in terms of overall performance, achieving optimal results in terms of precision (p = 98.7%), recall (R = 98.9%), mAP (99.4%), and parameter count (2,412,118). LGR-Net achieves low computational complexity and high detection accuracy, providing an efficient and effective solution for defect detection in elevator guide rail pressure plates. Full article

Traditional assessments of balance and postural control often face challenges related to accessibility, cost, subjectivity, and inter-rater reliability. With advancements in technology, smartphones equipped with inertial measurement units (IMUs) are emerging as a promising tool for assessing postural control, measuring both static and dynamic motion. This study aimed to develop and validate a novel smartphone application by comparing it with research-grade posturography instruments, including motion capture and force plate systems to establish construct- and criterion-related validity. Twenty-two participants completed the quiet stance under varying visual (eyes open—EO; eyes closed—EC) and surface (Firm vs. Foam) conditions, with data collected from the smartphone, force plate, and motion capture systems. Intraclass correlation coefficients (ICCs) and Pearson correlation coefficients assessed the reliability and validity for all outcome measures (sway area and sway velocity). The results demonstrated reliability, with strong validity between the devices. A repeated-measures ANOVA found no significant differences between the devices. Postural outcomes revealed the significant main effects of both the visual (EO vs. EC) and surface (Firm vs. Foam) conditions. In conclusion, the study demonstrated the validity, sensitivity, and accuracy of the custom-designed smartphone app, offering the potential for bridging the gap between at-home and clinical balance assessments. Full article

The extraction of deeply impacted lower third molars is a common yet challenging surgical procedure associated with complications such as mandibular fractures, pain, and swelling. This study evaluated the effectiveness of customized 3D-printed titanium plates in reducing the risk of intraoperative iatrogenic mandibular fractures. This innovative approach aims to improve surgical outcomes, enhance patient safety, and boost confidence for both surgeons and patients. Eighteen patients with Pell and Gregory class II/IIIC impacted lower third molars underwent preoperative CBCT scans, which facilitated the design and fabrication of customized plates and drilling guides. The surgical procedure involved incision, flap elevation, precise plate placement, osteotomy, odontotomy, extraction, and the postoperative assessment of pain, swelling, trismus, and anxiety using validated scales and facial scanning. The results show that customized titanium plates successfully prevented mandibular fractures in all cases. Although initial postoperative discomfort, including swelling, trismus, and pain, was observed, significant improvements occurred within one week. This technique provided structural reinforcement during surgery and healing without adverse events or fractures. Customized 3D-printed titanium plates represent a safe and effective solution for minimizing mandibular fractures, offering promising improvements in surgical outcomes. Full article

Gangue particle entrainment during flotation remains a significant challenge in mineral processing. Previous studies have shown that incorporating inclined plates into the froth zone can reduce the recovery of fine gangue particles. However, the effects of inclined channels on froth drainage have not been fully investigated. This study employed a custom-designed forced drainage system to systematically examine the impact of inclined channels on foam drainage and the underlying mechanisms. Results revealed that, at an SDS solution injection flow rate of 36 mL/min and an inclined channel angle of 30°, the foam drainage velocity in the inclined channel was significantly higher than that in the vertical channel for both two-phase and three-phase foams. This advantage became more pronounced as the SDS injection flow rate increased. A new drainage pathway formed between the inclined wall and the foam, facilitating faster liquid flow than within the foam structure. This mechanism was identified as the primary factor enhancing foam drainage velocity in inclined channels. These findings demonstrate that inclined channels can effectively improve foam drainage efficiency compared to vertical channels, providing valuable insights for optimizing froth zone structure. Full article

Cosmic ray muon tomography is a promising method for the non-invasive inspection of shipping containers and trucks. It leverages the highly penetrating cosmic muons and their interactions with various materials to generate three-dimensional images of large and dense objects, such as inter-modal shipping containers, which are typically opaque to conventional X-ray radiography techniques. One of the key tasks of customs and border security is verifying shipping container declarations to prevent illegal trafficking, and muon tomography offers a viable solution for this purpose. Common imaging methods using muons rely on data analysis of either muon scattering or absorption–transmission. We design a compact muon tomography system with dimensions of 3 × 3 × 3 m³, consisting of 2D position-sensitive detectors. These detectors include plastic scintillators, wavelength-shifting (WLS) fibers, and SiPMs. Through light transport modeling with GEANT4, we demonstrate that the proposed detector design—featuring 1 m × 1 m scintillator plates with 2 mm² square-shaped WLS fibers—can achieve a spatial resolution of approximately 0.7–1.0 mm. Through Monte Carlo simulations, we demonstrate that combining muon scattering and absorption data enables the rapid and accurate identification of cargo materials. In a smuggling scenario where tobacco is falsely declared as paper towel rolls, this combined analysis distinguishes the two with 3 $\sigma$ confidence at a spatial resolution of 1 mm (FWHM) for the muon detector, achieving results within a scanning time of 40 s for a 20-foot shipping container. Full article