Search Results (801)

Background: Hyaluronic acid (HA) hydrogels are the most widely used injectable fillers for facial rejuvenation. A new generation of HA fillers crosslinked with poly(ethylene glycol) diglycidyl ether (PEGDE) has been developed to enhance cohesiveness, tissue integration, stability, and longevity while minimizing swelling and immunogenicity. Owing to their distinct viscoelastic properties, PEGDE-crosslinked HA fillers may require product-specific selection and adapted injection techniques. Objective: The objective of this study is to provide practical, expert-based recommendations for the safe and effective use of PEGDE-crosslinked HA hydrogels in facial aesthetic treatments. Methods: A multidisciplinary panel of nine Italian experts in aesthetic medicine, each with more than 15 years of experience using HA fillers, developed consensus recommendations based on clinical practice and available evidence. A pre-meeting questionnaire informed structured discussions during a face-to-face meeting held in Paris in January 2024. The nominal group technique was applied, with consensus defined as agreement by at least 80% of panel members. Results: Consensus was reached on product selection, injection planes, delivery devices, techniques, and typical treatment volumes for PEGDE-HA hydrogels across multiple facial regions, including the forehead, temples, midface, nasolabial folds, chin, jawline, and lips. Recommended injection techniques included microbolus, macrobolus, and retrograde linear threading, with placement ranging from superficial subcutaneous to supraperiosteal planes depending on the anatomical area and clinical indication. Typical injection volumes generally ranged from 0.1 to 0.5 mL per side. Optional ultrasound mapping was considered beneficial in selected high-risk or superficial procedures to improve anatomical safety. Conclusions: These expert consensus recommendations provide practical guidance for clinicians using PEGDE-crosslinked HA hydrogels in facial rejuvenation. Tailoring product characteristics to injection depth, technique, and regional anatomy may help optimize clinical outcomes and procedural safety. Future research priorities include prospective comparative studies with other crosslinking technologies, standardized reporting of adverse events, long-term outcome registries, and further evaluation of ultrasound-guided injection strategies. Full article

To address the unobservability of distribution networks caused by insufficient coverage of measurement terminals as well as communication failures and missing data, and to cope with operating-state fluctuations induced by distributed generation integration and external environmental disturbances, this paper proposes an integrated state-estimation and voltage-regulation strategy that combines distribution-network-partitioning-based optimal PMU placement with pseudo-measurement construction using power transfer distribution factors (PTDFs). First, nodal reactive-power sensitivity information is derived from the power-flow Jacobian matrix, and an improved modularity function is employed to obtain the optimal partitioning of the distribution network, based on which PMUs are deployed at partition boundary buses. Second, PTDF-based power pseudo-measurements are constructed for unobservable buses and incorporated into the measurement model via a measurement transformation; a weighted least-squares method is then adopted to achieve system-wide state estimation. Finally, the estimated voltage states are fed into flexible voltage-regulation devices to enable fast and continuous voltage adjustment across buses. Case studies on the IEEE 33-bus system demonstrate that the proposed method effectively improves voltage quality. Full article

Long-term transthoracic echocardiogram (TTE) follow-up guidelines after muscular ventricular septal defect (mVSD) device closure are vague. The primary goal of this study was to perform a literature search to characterize the type and timing of complications that occur after mVSD device placement. The search was performed in Medline (PubMed) with English language and publication date (1983 to 2024) filters applied. Studies were included if they reported on patients who underwent mVSD device closure. Studies were excluded if they reported on other types of ventricular septal defect (VSD) device closures, were review papers, or did not report outcomes after the device procedure. A total of 139 articles met the criteria (retrospective, n = 63; prospective, n = 10; case reports, n = 66), encompassing 1668 patient cases. Age at the time of mVSD closure was 10.6 + 2.7 years. Incidence of complications was 17.9% (299/1668). Maximum follow-up was 160 months. Most complications were residual shunts (40.8%, 122/299), followed by valve dysfunction (13.7%, 41/299) and arrhythmias (13.7% 41/299). The vast majority of complications occurred ≤12 months post-device placement 98.0% (293/299). Only 1.3% (4/299) of complications occurred at >12 months (mild tricuspid regurgitation, n = 2; left bundle branch block, n = 1; atrial fibrillation, n = 1). Time until complication was not reported in 0.7% (2/299) of patients (residual shunts, n = 2). All clinically significant complications diagnosed via TTE occurred <12 months post-mVSD device procedure. The utility of repeat TTE beyond one year after mVSD device closure should be reassessed if no clinical concerns are present. Full article

Tilting pad journal bearings are critical components in high-speed turbomachinery. The use of sensors within the bearing is crucial to ensure operational safety and to validate computational models. The objective of this study is to improve the experimental investigation of the performance of a tilting pad journal bearing by enhancing the selection and placement of conventional and non-conventional sensors based on the results of a thermohydrodynamic model. The multi-sensor system measures film pressure and pad temperature at multiple locations, as well as pad tilt and film thickness. Redundant measurements are also performed to evaluate the performance of new induction coils capable of detecting magnetic flux variations due to vibrations. This work contributes to the discussion of bearing instrumentation by proposing a synergic sensor system comprising a suitable number of appropriately located conventional sensors together with non-conventional, non-invasive sensors. The experimental results obtained with the refined conventional sensor system agree with the predicted results, with differences that can be attributed to manufacturing and assembly tolerances of the bearing and simplified assumptions in the model. The results of the non-conventional sensor device, although promising, need further investigation. Full article

Background/Objectives: The anterior cruciate ligament (ACL) plays a key role in knee stability, biomechanics, and proprioception, and is one of the most frequently injured and reconstructed ligaments in both athletes and the general population. The anatomical placement of femoral and tibial tunnels close to the native ACL insertion sites is critical for long-term clinical outcomes and graft survival. This study aimed to define sagittal and coronal ACL alignment and tibial footprint morphology on magnetic resonance imaging (MRI) in healthy knees, to explore sex- and side-related differences, and to provide population-specific reference values. Methods: In this retrospective cross-sectional study, knee MRIs acquired between 2018 and 2021 were screened, and knees with an intact ACL and without deformity or joint pathology that could alter alignment were included. After applying inclusion and exclusion criteria, 636 knees (320 right, 316 left) from 545 individuals (338 women, 298 men; 15–80 years, mean age 34.87 ± 11.65 years) were analyzed. On sagittal images, the sagittal ACL angle (S-ANGLE) was measured on the slice where the ligament appeared maximally visualized. The midpoints of the ACL were identified on two adjacent sagittal slices, and a line drawn through these midpoints was used to represent the central axis of the ligament; the angle between this line and the tibial plateau was recorded as the S-ANGLE. For anteroposterior localization of the tibial footprint, an anteroposterior reference distance (S-long) was defined as the length measured parallel to the tibial plateau, extending from the midpoint of the tibial tuberosity (corresponding to the insertion site of the patellar ligament and used as a topographic anterior landmark) toward the posterior aspect of the proximal tibia. A perpendicular line was drawn from the anterior end of S-long to establish the anterior reference boundary. The distance from this anterior reference line to the midpoint of the ACL tibial footprint along the same anteroposterior axis was defined as S-short. The sagittal footprint percentage (S-PERCENTAGE) was calculated as (S-short/S-long) × 100, representing the size-normalized sagittal anteroposterior position of the ACL tibial footprint midpoint. On coronal images, the ACL–tibial plateau angle (C-ANGLE), mediolateral tibial length (C-LONG), and distance from the medial edge to the ACL insertion (C-short) were obtained; C-PERCENTAGE was calculated analogously. Medial mechanical proximal tibial angle (mMPTA) was used to confirm physiological coronal alignment. Non-parametric tests were applied, with p < 0.05 considered statistically significant. Results: Women had significantly greater sagittal ACL angles than men, whereas anteroposterior distances measured from the midpoint of the tibial tuberosity (used as an anterior topographic landmark) and oriented parallel to the tibial plateau (S-LONG) and mediolateral tibial lengths (C-LONG) and absolute distances to the ACL tibial footprint were larger in men. In contrast, normalized sagittal and coronal footprint percentages (S-PERCENTAGE, C-PERCENTAGE) did not differ meaningfully between sexes, indicating the preservation of the relative ACL tibial insertion site despite size differences. Small but statistically significant side-to-side differences were observed in some coronal parameters; however, absolute differences were small and did not substantially modify the overall alignment pattern. Conclusions: This study provides large-sample, population-specific reference values for ACL orientation and tibial footprint location in both sagittal and coronal planes in healthy knees. The combination of higher sagittal ACL angles and shorter anteroposterior distances reference measured from the midpoint of the tibial tuberosity and oriented parallel to the tibial plateau (S-LONG) in women may represent a structural substrate contributing to the higher ACL injury rates reported in females. The morphometric data presented here may assist in individualized ACL reconstruction planning, MRI-based assessment of tibial tunnel position, and the design of knee-related biomedical implants and devices. Full article

The thermal dissipation performance of the radiator is crucial for the stable operation of power electronic devices. Due to excellent thermal performance, copper pin-type heat sink substrates are widely adopted. However, the cold extrusion process for heat sink substrates suffers from low material utilization and high forming loads. To improve material utilization and reduce cold extrusion forming load, four blank shapes (rectangular, trapezoidal, trapezoidal cap, and stepped) were designed using finite-element simulation to investigate the effects of blank shape and placement method with orientation relative to the die cavity on forming quality. Further dimensional optimization was conducted to determine the optimal configuration. The results show that the stepped blank with front orientation exhibits the optimal forming performance, featuring the lowest forming load and the most sufficient pin-fin filling. Compared with back orientation, front orientation achieves higher and more uniform material flow velocity, and significantly reduces forming load. Through dimension optimization, the 7 mm-thick stepped blank is determined as the optimal solution, with the forming load reduced to 15,000 kN (a 35.3% decrease compared to the initial 7.5 mm stepped blank), and both the substrate thickness and pin-fin height meet the design requirements (4.5 mm and 6.5 mm). Experiments verify the feasibility of the optimized scheme, providing technical support for the low-cost, high-quality mass production of copper pin-type heat sink substrates. Full article

This study evaluated the biomechanically optimal insertion angle for miniscrew-assisted anterior intrusion by analyzing stress in the periodontal ligament (PDL) and alveolar bone. A three-dimensional finite element model from cone-beam computed tomography (CBCT) data, comprising maxillary bone, anterior dentition, and a bonded orthodontic appliance, and segmented 0.019 × 0.025-inch stainless-steel archwire were used. Titanium miniscrews (1.4 × 6 mm) were placed at 5 mm from the alveolar crest between the lateral incisor and canine. Four insertion angulations relative to the occlusal plane (30°, 60°, 90°, and 120°) were simulated under a 90 g intrusive force. Results demonstrated that while all configurations achieved intrusion with minor labial tipping and maintained miniscrew stability, stress localization was highly angle-dependent: the 90° insertion generated the highest central incisor PDL tensile stress and maximum cortical bone Von Mises stress; the 120° insertion yielded peak canine PDL Von Mises stress and maximum root displacement; and the 60° insertion localized peak stresses within the cancellous bone and the bone–implant interface. Miniscrews remained stable in all scenarios. While all tested miniscrew angulations provided stable anchorage for upper anterior teeth intrusion, the selection of insertion angle critically influenced stress patterns within the supporting tissues. Full article

The proliferation of distributed photovoltaic (PV) generation introduces significant operational challenges for distribution networks, including voltage instability and elevated technical losses. While modern PV inverters capable of static synchronous compensator (STATCOM) functionality—forming PV-STATCOM systems—offer a promising solution, their optimal integration remains a complex mixed-integer non-linear programming (MINLP) problem. This paper addresses this gap by proposing a novel hybrid evaluator–optimizer framework for the optimal daily placement and sizing of PV-STATCOM devices. The framework synergistically integrates the metaheuristic crow search algorithm (CSA) for global exploration of discrete device locations with a high-fidelity, multi-period optimal power flow (OPF) model—implemented efficiently in Julia with the Ipopt solver—for continuous operational evaluation and constraint validation. The methodology incorporates realistic 24 h load and solar irradiance profiles. Extensive validation on standard IEEE 33- and 69-bus test systems demonstrates the efficacy of the proposed approach. The results indicate substantial reductions in daily energy losses—by up to 70.4% and 72.9% for the 33- and 69-bus systems, respectively—and corresponding operational costs, outperforming recent state-of-the-art metaheuristic and convex optimization methods reported in the literature. The CSA also exhibits robust convergence and repeatability across multiple independent runs. This work contributes a computationally efficient, open-source planning tool that leverages modern optimization solvers, providing a scalable and effective strategy for enhancing the power quality and economic performance of PV-rich distribution networks. Full article

Conventional pneumatic precision planters still face challenges in combining high-speed operation with accurate seed placement and embryo protection under zero-velocity seeding conditions. This study presents a dual-motor rotating–throwing seed-metering device that simultaneously overcomes these challenges. Instead of relying on conventional imprecise airflow to generate initial velocity, seeds are accelerated and released by a motor-driven spoon with precisely defined kinematic profiles. By accurately controlling seed-throwing velocity and angle, the system compensates for the forward motion of the machine to achieve zero-velocity seeding and accurate landing point control across the full speed range. The elimination of seed tubes prevents frictional embryo damage, particularly benefiting fragile seeds such as cotton or peanuts. High-speed imaging (1000 fps) verified uniform initial seed ejection conditions, stable trajectories, and landing position errors below 1.5 cm at 7–13 km/h. The proposed electromechanical approach provides accurate metering, zero-velocity seeding, and seed protection under high-speed conditions, overcoming the inherent limitations of airflow-dependent systems and offering a robust alternative for precision agriculture. Compared with conventional pneumatic meters, the proposed system reduced seed landing variation by over 50%, demonstrating superior robustness under 7–13 km/h operation. Full article

This paper presents an in-depth analysis of a non-isolated buck–boost DC–DC converter which uses coupled inductors. The converter is designed to achieve a high static conversion ratio while using a moderate number of semiconductor devices. The proposed topology, originally introduced in a former paper of the authors, under ideal operating conditions, is now evaluated taking into account non-ideal components, modeling the conduction losses of the semiconductor devices and the equivalent series resistance of the output capacitor. In order to get a regulated output voltage, closed-loop behavior is also investigated. By using the state-space modeling approach, the calculation of the converter static conversion ratio and control-to-output transfer functions is performed. Because the topology is of fourth order, a procedure for controller design is provided. A type III error amplifier is chosen, and the pole-zero placement technique is used for its design, demonstrating that the classical control strategy still works even with this fourth-order converter. Thus, a good phase margin of 62.3 degrees is achieved. The theoretical results are validated both on open-loop and closed-loop operation, in the presence of conduction losses. Furthermore, a laboratory prototype is implemented, and it validates the theoretical and simulation results. The study demonstrates that the proposed coupled inductors buck–boost converter is a good choice for step-up applications that need a large difference between input and output voltages. Full article

Interactive teleoperation offers an intuitive pathway for human–robot interaction, yet many existing systems rely on dedicated sensors or wearable devices, limiting accessibility and scalability. This paper presents a vision-based teleoperation framework that enables real-time control of an articulated robotic arm (five joints plus a gripper actuator) using human hand tracking from a single, typical laptop camera. Hand pose and gesture information are extracted using a real-time landmark estimation pipeline, and a set of compact kinematic descriptors—palm position, apparent hand scale, wrist rotation, hand pitch, and pinch gesture—are mapped to robotic joint commands through a calibration-based control strategy. Commands are transmitted over a lightweight network interface to an embedded controller that executes synchronized servo actuation. To enhance stability and usability, temporal smoothing and rate-limited updates are employed to mitigate jitter while preserving responsiveness. In a human-in-the-loop evaluation with 42 participants, the system achieved an 88% success rate (37/42), with a completion time of 53.48 ± 18.51 s, a placement error of 6.73 ± 3.11 cm for successful trials (n = 37), and an ease-of-use score of 2.67 ± 1.20 on a 1–5 scale. Results indicate that the proposed approach enables feasible interactive teleoperation without specialized hardware, supporting its potential as a low-cost platform for robotic manipulation, education, and rapid prototyping. Full article

Cardiogenic shock (CS) remains a life-threatening syndrome characterized by reduced cardiac output and end-organ hypoperfusion, most commonly resulting from acute myocardial infarction (AMI). Despite advances in early revascularization and increasing use of percutaneous mechanical circulatory support (MCS), short-term mortality in AMI-related CS (AMI-CS) remains high. This review summarizes the contemporary evidence on short-term percutaneous MCS in AMI-CS, with a focus on intra-aortic balloon pump (IABP), Impella microaxial flow pumps, and venoarterial extracorporeal membrane oxygenation (VA-ECMO), and provides insights into device selection and implementation in clinical practice. We performed a comprehensive analysis of the most relevant randomized controlled trials and key guideline recommendations from European and North American societies concerning the use of MCS. Despite its long-standing, IABP has not demonstrated a mortality benefit in contemporary trials and is no longer recommended for routine use in AMI-CS without mechanical complications. Nevertheless, it remains widely used due to its simplicity, safety profile, and broad availability. In contrast, Impella devices provide active left ventricular unloading and have shown promising hemodynamic effects, with the DanGer Shock trial suggesting a potential survival benefit in carefully selected patients, at the expense of higher complication rates. VA-ECMO offers full cardiopulmonary support but is associated with the highest complication rates and increases left ventricular afterload, often requiring adjunctive unloading with devices such as Impella (ECPELLA). However, recent randomized trials have not demonstrated a clear survival advantage for VA-ECMO, and concerns regarding its complications persist. In conclusion, CS continues to pose major therapeutic challenges, and no single MCS device has consistently shown a survival benefit across all AMI-CS patient populations. Individualized, phenotype-driven strategies that incorporate hemodynamic profiling and timely escalation of support are essential. Further randomized studies are urgently needed to define optimal device selection, the timing of placement, and appropriate patient selection criteria. Institutional protocols guided by clinical stage, etiology, and available expertise will be pivotal in improving outcomes. Full article

Magnetoencephalography (MEG) based on optically pumped magnetometers (OPMs) offers the flexibility to position sensors closer to the scalp, which improves the signal-to-noise ratio compared to conventional superconducting quantum interference device (SQUID) systems. However, the spatial resolution of OPM-MEG critically depends on sensor placement, especially when the number of sensors is limited. In this study, we present a methodology for optimizing OPM-MEG sensor layouts using each subject’s anatomical information derived from individual magnetic resonance imaging (MRI). We generated realistic forward models from reconstructed head surfaces and simulated magnetic fields produced by equivalent current dipoles (ECDs). We compared multiple simulation strategies, including ECDs randomly distributed across the cortical surface and ECDs constrained to regions of interest. For each simulated magnetic field map (MFM) database, we applied the sequential selection algorithm (SSA) to identify sensor positions that maximized information capture. Unlike previous approaches relying on large measurement databases, this simulation-driven strategy eliminates the need for extensive pre-existing recordings. We benchmarked the performance of the personalized layouts using OPM-MEG datasets of auditory evoked fields (AEFs) derived from real whole-head SQUID-MEG measurements. Our results show that simulation-based SSA optimization improves the coverage of cortical regions of interest, reduces the number of sensors required for accurate source reconstruction, and yields sensor configurations that perform comparably to layouts optimized using measured data. To evaluate the quality of estimated MFMs, we applied metrics such as the correlation coefficient (CC), root-mean-square error, and relative error. Our results show that the first 15 to 20 optimally selected sensors (CC > 0.95) capture most of the information contained in full-head MFMs. Additionally, we performed source localization for the highest auditory response (M100) by fitting equivalent current dipoles and found that localization errors were < 5 mm. The results further indicate that SSA performance is insensitive to individualized head geometry, supporting the feasibility of using representative anatomical models and highlighting the potential of this approach for clinical OPM-MEG applications. Full article

Cleanrooms are essential environments for the production of sterile pharmaceuticals and medical devices, where airflow stability and contamination control are critical. In this study, the influence of adjustable worktable height on air cleanliness was examined to determine whether height variation affects unidirectional airflow and particle concentration. Measurements were conducted under laboratory conditions in an ISO Class 6 cleanroom and in an industrial ISO Class 8 production line. Particle concentrations were recorded at table heights between 70 and 120 cm using a calibrated particle counter in accordance with ISO 14644-1 and ISO 21501-4. The measured data were evaluated against the classification limits defined in ISO 14644-1. Across all height levels, particle concentrations remained well below the permissible thresholds. In the ISO Class 6 cleanroom, measurement height showed a statistically significant effect on particles >5 μm, though this represented only a small contribution to the overall variance. In contrast, no significant height effect was observed in the ISO Class 8 cleanroom. Observed local differences were attributed to airflow distribution and the placement of air supply in-/outlets rather than table height. These results confirm that height-adjustable worktables can be implemented without affecting cleanroom classification, provided that uniform FFU placement and furniture positioning are considered during design and qualification. Full article

Dielectric barrier discharge (DBD) plasma actuators (PAs) are devices used to control airflow. DBD actuators generate an electric field that accelerates ionized air particles, inducing localized flow modifications. Among other applications, they are particularly effective for enhancing cooling, for aerodynamic drag reduction, and for lift enhancement, therefore capable of improving stall characteristics. In addition, they offer several distinct advantages, such as rapid response time, low power consumption, and no moving parts. The present review paper aims to summarize the main governing equations associated with the most common phenomenological PA Computational Fluid Dynamics (CFD) models, Shyy and Suzen-Huang, as well as highlight the major applications to flat plates, wind turbine airfoils and entire wind turbines. The application of DBD plasma actuators on individual wind turbine blades, as well as dynamic horizontal and vertical axis wind turbines, is reviewed, drawing from key numerical and experimental investigations. The simulated performance of various configurations of single and multiple PAs on representative airfoils at different chordwise locations is discussed. The overall findings indicate that the chordwise location of the actuators on airfoils and their optimum spanwise placement on small and large wind turbine blades, along with the geometry and excitation parameters of the actuators, play a crucial role in their performance, affecting the boundary layer and the flow pattern. The reader shall obtain an overall idea of the most recent aerodynamic applications of PAs as well as their expected efficiency. Full article