Search Results (271)

Event-based vision sensors (EVSs), often referred to as neuromorphic cameras, operate by responding to changes in brightness on a pixel-by-pixel basis. In contrast, traditional framing cameras employ some fixed sampling interval where integrated intensity is read off the entire focal plane at once. Similar to traditional cameras, EVSs can suffer loss of sensitivity through scenes with high intensity and dynamic clutter, reducing the ability to see points of interest through traditional event processing means. This paper describes a method to reduce the negative impacts of these types of EVS clutter and enable more robust target detection through the use of individual pixel frequency analysis, background suppression, and statistical filtering. Additionally, issues found in normal frequency analysis such as phase differences between sources, aliasing, and spectral leakage are less relevant in this method. The statistical filtering simply determines what pixels have significant frequency content after the background suppression instead of focusing on the actual frequencies in the scene. Initial testing on simulated data demonstrates a proof of concept for this method, which reduces artificial scene noise and enables improved target detection. Full article

Continuous SiC fiber-reinforced SiC matrix composites (SiC/SiC), as structural heat protection integrated materials, are often used in parts for large-area heat protection and sharp leading edges, and there are a variety of low-velocity impact events in their service. In this paper, a drop hammer impact test was conducted using narrow strip samples to simulate the low-velocity impact damage process of sharp-edged components. During the test, different impact energies and impact times were set to focus on investigating the low-velocity impact damage characteristics of 2.5D SiC/SiC composites. To further analyze the damage mechanism, computed tomography (CT) was used to observe the crack propagation paths and distribution states of the composites before and after impact, while scanning electron microscopy (SEM) was employed to characterize the differences in the micro-morphology of their fracture surfaces. The results show that the in-plane impact behavior of a 2.5D needled SiC/SiC composite strip samples differs from the conventional three-stage pattern. In addition to the three stages observed in the energy–time curve—namely in the quasi-linear elastic region, the severe load drop region, and the rebound stage after peak impact energy—a plateau stage appears when the impact energy is 1 J. During the impact process, interlayer load transfer is achieved through the connection of needled fibers, which continuously provide significant structural support, with obvious fiber pull-out and debonding phenomena. When the samples are subjected to two impacts, damage accumulation occurs inside the material. Under conditions with the same total energy, multiple impacts cause more severe damage to the material compared to a single impact. Full article

Efficient object detection is crucial to real-time monitoring applications such as autonomous driving or security systems. Modern RGB cameras can produce high-resolution images for accurate object detection. However, increased resolution results in increased network latency and power consumption. To minimise this latency, Convolutional Neural Networks (CNNs) often have a resolution limitation, requiring images to be down-sampled before inference, causing significant information loss. Event-based cameras are neuromorphic vision sensors with high temporal resolution, low power consumption, and high dynamic range, making them preferable to regular RGB cameras in many situations. This project proposes the fusion of an event-based camera with an RGB camera to mitigate the trade-off between temporal resolution and accuracy, while minimising power consumption. The cameras are calibrated to create a multi-modal stereo vision system where pixel coordinates can be projected between the event and RGB camera image planes. This calibration is used to project bounding boxes detected by clustering of events into the RGB image plane, thereby cropping each RGB frame instead of down-sampling to meet the requirements of the CNN. Using the Common Objects in Context (COCO) dataset evaluator, the average precision (AP) for the bicycle class in RGB scenes improved from 21.08 to 57.38. Additionally, AP increased across all classes from 37.93 to 46.89. To reduce system latency, a novel object detection approach is proposed where the event camera acts as a region proposal network, and a classification algorithm is run on the proposed regions. This achieved a 78% improvement over baseline. Full article

The transport of intensity equation enables quantitative phase imaging from only two axially displaced intensity images, facilitating the characterization of low-contrast samples like cells and microorganisms. However, the rapid selection of the correct defocused planes, crucial for real-time phase imaging of dynamic events, remains challenging. Additionally, the different images are normally acquired sequentially, further limiting phase-reconstruction speed. Here, we report on a system that addresses these issues and enables user-tuned defocusing with snapshot phase retrieval. Our approach is based on combining multi-color pulsed illumination with acousto-optic defocusing for microsecond-scale chromatic aberration control. By illuminating each plane with a different color and using a color camera, the information to reconstruct a phase map can be gathered in a single acquisition. We detail the fundamentals of our method, characterize its performance, and demonstrate live phase imaging of a freely moving microorganism at speeds of 150 phase reconstructions per second, limited only by the camera’s frame rate. Full article

Background/Objective: Laser therapy has gained attention in dental practice to minimize bleeding and enhance blood clot formation. This study aimed to explore the utilization and to compare the clinical efficacy of laser-mediated hemostasis for older patients receiving routine dental treatment. Methods: A prospective observational study was conducted across research networks between October 2023 and August 2024, involving 60 patients aged 50 years and older (average = 63.35 years) at risk of postoperative bleeding following dental treatments. Additionally, laser therapy for hemostasis was selected and provided among calibrated operators. A single researcher performed data collection. Before statistical analysis, data verification and clinical assessment were conducted by the operators and researcher. A clinical cut-off for hemostasis was set at 5 min. Two diode laser machines were used namely, an 810 nm and dual wavelengths of 635 nm and 980 nm. Results: There were 94 extraction sockets, 28 procedures of scaling and root planing and 18 procedures of minor oral surgery. Combining laser ablating sulcular fiber and photobiomodulation initiating blood clot formation was a preferable hemostatic technique for extraction socket, while photobiomodulation alone was a preferred technique for soft tissue hemostasis (p < 0.001). All operators confirmed that 97.86 percent of bleeding events achieved more rapid hemostasis. 61.43 percent of bleeding events clinically achieved hemostasis within 5 min by using laser-mediated hemostasis alone (p = 0.092). Full recovery of the extraction socket was significantly observed during the 2- to 4-week follow-up period (p = 0.005). No clinical complications were reported. Conclusions: Laser-mediated hemostasis effectively reduced hemostatic duration, prevented postoperative bleeding and promoted wound healing in older patients undergoing routine dental treatment. Full article

Adobe churches are representative of Andean architectural heritage, yet their structural vulnerability to seismic events remains a significant concern. This study evaluates the seismic performance of the 17th-century Church of Santo Tomás de Aquino in Rondocan, Peru, an adobe building that underwent conservation work in the late 1990s. The assessment combines in situ inspections and experimental testing with advanced nonlinear numerical modeling. A finite-element macro-model was developed and calibrated using sonic and ambient vibration tests to replicate the observed structural behavior. Nonlinear static (pushover) analyses were performed in the four principal directions to identify failure mechanisms and to evaluate seismic capacity using the Peruvian seismic code. Kinematic limit analyses were conducted to assess out-of-plane mechanisms using force- and displacement-based criteria. The results revealed critical vulnerabilities in the rear façade and lateral walls, particularly in terms of out-of-plane collapse, while the main façade exhibited a higher capacity but a brittle failure mode. This study illustrates the value of advanced numerical simulations, calibrated with field data, as effective tools for assessing seismic vulnerability in historic adobe buildings. The outcomes highlight the necessity of strengthening measures to balance life safety requirements with preservation goals. Full article

This research addresses critical challenges in clinical gait analysis by developing an automated video quality assessment framework to support Edinburgh Visual Gait Score (EVGS) scoring. The proposed methodology uses the MoveNet Lightning pose estimation model to extract body keypoints from video frames, enabling detection of multiple persons, tracking the person of interest, assessment of plane orientation, identification of overlapping individuals, detection of zoom artifacts, and evaluation of video resolution. These components are integrated into a unified quality classification system using a random forest classifier. The framework achieved high performance across key metrics, with 96% accuracy in detecting multiple persons, 95% in assessing overlaps, and 92% in identifying zoom events, culminating in an overall video quality categorization accuracy of 95%. This performance not only facilitates the automated selection of videos suitable for analysis but also provides specific video improvement suggestions when quality standards are not met. Consequently, the proposed system has the potential to streamline gait analysis workflows, reduce reliance on manual quality checks in clinical practice, and enable automated EVGS scoring by ensuring appropriate video quality as input to the gait scoring system. Full article

Background: Periodontitis is linked to sleep-disordered breathing (SDB), including snoring, with 50–75% of cases involving mouth breathing (MB). Standard treatment includes scaling and root planing (SRP). Oral appliance therapy (OAT) is used to treat snoring and SDB. OAT plus a mouth shield (OAT+) worn during sleep may reduce MB to enhance periodontal health. This study evaluated whether OAT+, as an adjunct to SRP, improves periodontal health by reducing periodontal pathogens and facilitating upper airway patency. Methods: Fourteen participants with mild–moderate periodontitis were randomized to receive SRP on one side of the mouth at baseline (T0). Pocket depth (PD), bleeding on probing (BOP), and plaque index (PI) were recorded, and bacterial DNA from periodontal pockets were analyzed via PCR at baseline (T0) and 12 weeks (T3). At 4 weeks (T1), all participants received a self-titrated myTAP^® OA, followed by a mouth shield at 8 weeks (T2). Sleep metrics, including respiratory disturbance index (RDI), were recorded using the NOX T3 at T0–T3. Results: BOP and deep PD levels exhibited slight improvements from the baseline for both SRP and non-SRP (OAT+ only) treated sites but did not achieve significance. BOP decreased significantly more from the baseline in the SRP than in the non-SRP group at T3 (p = 0.028); P. gingivalis’ presence declined on both sides (p = 0.0135). Other periodontal and bacterial parameters showed no significant differences between or within groups. Snoring (p = 0.011), MB (p = 0.025), and RDI (p = 0.019) significantly decreased with OAT+ at T3. Conclusions: In mild–moderate periodontitis patients who snore, OAT+ reduces snoring, MB, and obstructive events, serving as an adjunct to SRP with no negative clinical effects over the short term. The combined therapy yielded similar results to OAT+ alone, likely due to minimization of MB. Its capacity to improve the oral environment is worthy of further investigation. Full article

Wideband electromagnetic pulse detection is a crucial method for lightning disaster monitoring. However, the random nature of lightning events presents challenges in fulfilling real-time calibration requirements for electromagnetic pulse sensors. This paper introduces a segmented ultra-wideband TEM horn antenna tailored for portable calibration experiments in electromagnetic pulse detection systems. The radiating plates feature a four-section polygonal design, and an end-loaded metal plate is integrated to reduce reflection signal interference. Rigorous simulation analyses were performed on three key factors impacting antenna radiation performance: aperture impedance, tapering profile, and end loading configuration. Experimental results show that the designed antenna achieves a peak field strength of 48.9 V/m at a 10 m distance, with a rise time of 0.87 ns and a full width at half maximum of 1.75 ns. The operating frequency ranges from 48 MHz to 150 MHz, with main lobe beamwidths of 43° and 83° in the E-plane and H-plane radiation patterns, respectively. These parameters meet the technical requirements for electromagnetic pulse sensor calibration experiments. Full article

As populations age, particularly in countries like Japan, mobility impairments related to ankle joint dysfunction, such as foot drop, instability, and reduced gait adaptability, have become a significant concern. Active ankle–foot orthoses (AAFO) offer targeted support during walking; however, most existing systems rely on rule-based or threshold-based control, which are often limited to sagittal plane movements and lacking adaptability to subject-specific gait variations. This study proposes an approach driven by neuromuscular activation using surface electromyography (EMG) and a Gated Recurrent Unit (GRU)-based deep learning model to predict plantar pressure distributions at the heel, midfoot, and toe regions during gait. EMG signals were collected from four key ankle muscles, and plantar pressures were recorded using a customized sandal-integrated force-sensitive resistor (FSR) system. The data underwent comprehensive preprocessing and segmentation using a sliding window method. Root mean square (RMS) values were extracted as the primary input feature due to their consistent performance in capturing muscle activation intensity. The GRU model successfully generalized across subjects, enabling the accurate real-time inference of critical gait events such as heel strike, mid-stance, and toe off. This biomechanical evaluation demonstrated strong signal compatibility, while also identifying individual variations in electromechanical delay (EMD). The proposed predictive framework offers a scalable and interpretable approach to improving real-time AAFO control by synchronizing assistance with user-specific gait dynamics. Full article

Background: Hypotension is a common adverse event after the induction of general anesthesia and may lead to serious complications. The Tricuspid Annular Plane Systolic Excursion (TAPSE)/Pulmonary Arterial Systolic Pressure (PASP) ratio is an echocardiographic parameter reflecting right ventricular (RV) function and pulmonary circulation. This study aimed to evaluate the predictive value of the TAPSE/PASP ratio for hypotension after general anesthesia induction. Methods: This prospective observational study included 79 patients with no known cardiac disease who were scheduled for elective surgery and classified as having a physical status of I–III according to the American Society of Anesthesiologists (ASA). TAPSE, PASP, and RV function were assessed using transthoracic echocardiography (TTE) within 5–30 min before surgery, and their hemodynamic changes after general anesthesia induction were recorded. Results: Data analysis revealed a significant association between the TAPSE/PASP ratio and the occurrence of hypotension following the induction of general anesthesia (p < 0.001). In addition, a cut-off value of ≤1.98 was determined for predicting hypotension, which demonstrated a sensitivity of 72.5% and a specificity of 64.1% (AUC = 0.733, 95% CI: 0.621–0.826, p < 0.001). Conclusions: The TAPSE/PASP ratio is a potential predictor of hypotension following the induction of general anesthesia. Further studies are required to validate its predictive accuracy and clinical utility in perioperative hemodynamic management. Full article

The Edinburgh Visual Gait Score (EVGS) is a commonly used clinical scale for assessing gait abnormalities, providing insight into diagnosis and treatment planning. However, its manual implementation is resource-intensive and requires time, expertise, and a controlled environment for video recording and analysis. To address these issues, an automated approach for scoring the EVGS was developed. Unlike past methods dependent on controlled environments or simulated videos, the proposed approach integrates pose estimation with new algorithms to handle operational challenges present in the dataset, such as minor camera movement during sagittal recordings, slight zoom variations in coronal views, and partial visibility (e.g., missing head) in some videos. The system uses OpenPose for pose estimation and new algorithms for automatic gait event detection, stride segmentation, and computation of the 17 EVGS parameters across the sagittal and coronal planes. Evaluation of gait videos of patients with cerebral palsy showed high accuracy for parameters such as hip and knee flexion but a need for improvement in pelvic rotation and hindfoot alignment scoring. This automated EVGS approach can minimize the workload for clinicians through the introduction of automated, rapid gait analysis and enable mobile-based applications for clinical decision-making. Full article

This study focuses on the investigation of the Tepehan landslide triggered by the 6 February 2023, Kahramanmaraş earthquake in Türkiye. The overall goal of this study is to understand the slope condition and simulate the failure considering pre- and post-event geometry. Topographic variations in the landslide area were analyzed using digital elevation models (DEMs) derived from the Sentinel-1 Synthetic Aperture Radar (SAR) satellite data and geospatial analysis. Slope stability analyses were conducted over a representative alignment, including assessments of soil structure, geological history, and field features. A limit equilibrium back-analysis was performed under both static and pseudo-static conditions, where an earthquake load coefficient was considered in the analyses. A total of five scenarios were evaluated to determine factors of safety (FoS) based on fully softened and residual strength parameters. The resulting critical slip surfaces from the simulations were compared with the geomorphometric analysis, necessitating the adjustment of the subsurface hard clay layer for residual conditions. The analyses revealed that the slope behaves as a delayed first-time landslide, with bedding planes acting as localized weak layers, reducing mobilized shear strength. This integrated remote sensing–geotechnical approach advances landslide hazard evaluation by enhancing the precision of slip surface identification and post-seismic slope behavior modeling, offering a valuable framework for similar post-disaster geohazard assessments. Full article

Effective postoperative pain management is crucial for optimizing recovery and clinical outcomes in living donor kidney transplantation (LDKT). This retrospective study compared the efficacy and safety of transversus abdominis plane (TAP) block and local wound infiltration (LWI) for postoperative analgesia. A total of 524 LDKT recipients, matched through propensity scoring, were analyzed (262 per group). Pain intensity was assessed using the visual analog scale (VAS) at multiple postoperative time points, while opioid consumption was evaluated based on intravenous patient-controlled analgesia (IV-PCA) usage and rescue fentanyl doses. The TAP block group had significantly lower VAS pain scores at 1, 4, and 8 h postoperatively (p < 0.001) and required fewer opioids, as evidenced by reduced IV-PCA usage (55.9 ± 10.2 mL vs. 69.7 ± 18.2 mL; p < 0.001) and lower rescue fentanyl doses (67.7 ± 30.6 µg vs. 119.1 ± 71.8 µg; p < 0.001). Despite these differences in analgesic efficacy, no significant differences were observed between the groups in terms of postoperative nausea and vomiting or complications such as systemic toxicity and nerve injury. These findings suggest that the TAP block provides more effective early postoperative pain relief and reduces opioid requirements without increasing adverse events. Given its favorable safety profile and effectiveness, the TAP block is a valuable component of multimodal analgesia in LDKT recipients, supporting enhanced recovery while minimizing opioid-related complications. Full article

Background: An erector spinae plane block (ESPB) has gained popularity due to its effectiveness and simplicity for pain relief. However, it is uncertain whether an ESPB provides superior analgesia after a VATS or thoracotomy compared to other regional and systemic analgesic techniques. Methods: A retrospective cohort study was conducted from January to June 2023 comparing an ESPB with intravenous combination analgesia (IV–CA) in VATS patients and with thoracic epidural analgesia (TEA) in thoracotomy patients. The primary endpoint was the opioid demand during the first two hours in the post-anesthesia care unit (PACU). The secondary outcomes included the pain scores and adverse events. Results: A total of 61.2% of the 165 included VATS patients and 56.9% of the 72 thoracotomy patients were treated with an ESPB. Following a VATS, an ESPB decreased the median piritramide demand (7.5 [3.0 to 12.0] vs. 10.5 [6.5 to 15.5] mg, p < 0.01). However, after a thoracotomy, an ESPB increased the median piritramide demand (12.0 [6.0 to 15.0] vs. 3.0 [0.0 to 9.0] mg, p < 0.01). The pain scores and adverse events were similar between the groups. Conclusions: An ESPB reduces the piritramide demand in VATS patients compared with IV–CA, providing similar pain relief. However, in thoracotomy patients, an ESPB is associated with an increased piritramide demand compared to TEA. An ESPB is an attractive add-on to IV–CA after a VATS, while TEA remains the gold standard after a thoracotomy. Full article