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13 pages, 4772 KiB  
Article
Design of Low-SAR High-Efficiency Terminal Antenna Using Magnetic Field Homogenization
by Sihan Xiao, Yong-Chang Jiao, Ziming Lv, Liupeng Zan and Zibin Weng
Micromachines 2025, 16(8), 856; https://doi.org/10.3390/mi16080856 - 25 Jul 2025
Viewed by 214
Abstract
A low-SAR high-efficiency terminal antenna based on the magnetic field homogenization is proposed in this paper. Starting from the spatial correlation between the antenna’s near-field tangential magnetic field hotspots and SAR distribution, the influence of hotspot distribution on SAR was analyzed, and we [...] Read more.
A low-SAR high-efficiency terminal antenna based on the magnetic field homogenization is proposed in this paper. Starting from the spatial correlation between the antenna’s near-field tangential magnetic field hotspots and SAR distribution, the influence of hotspot distribution on SAR was analyzed, and we found that a homogenized tangential magnetic field distribution can reduce the SAR without compromising the radiation efficiency. Based on the SAR reduction mechanism, a low-SAR high-efficiency terminal antenna was designed. By adjusting the magnetic field distributions on two planes with the highest initial SARs, 39% and 27% SAR reduction is achieved, respectively. Measurement results show that the antenna operates in the 3.3 GHz to 3.8 GHz band, with a radiation efficiency exceeding 69%, and a peak 10 g average SAR of 1.39 W/kg at 3.6 GHz. Full article
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14 pages, 3371 KiB  
Article
A Symmetry-Driven Broadband Circularly Polarized Magnetoelectric Dipole Antenna with Bandpass Filtering Response
by Xianjing Lin, Zuhao Jiang, Miaowang Zeng and Zengpei Zhong
Symmetry 2025, 17(7), 1145; https://doi.org/10.3390/sym17071145 - 17 Jul 2025
Viewed by 176
Abstract
This paper presents a symmetry-driven broadband circularly polarized magnetoelectric dipole antenna with bandpass filtering response, where the principle of symmetry is strategically employed to enhance both radiation and filtering performance. The antenna’s circular polarization is achieved through a symmetrical arrangement of two orthogonally [...] Read more.
This paper presents a symmetry-driven broadband circularly polarized magnetoelectric dipole antenna with bandpass filtering response, where the principle of symmetry is strategically employed to enhance both radiation and filtering performance. The antenna’s circular polarization is achieved through a symmetrical arrangement of two orthogonally placed metallic ME dipoles combined with a phase delay line, creating balanced current distributions for optimal CP characteristics. The design further incorporates symmetrical parasitic elements—a pair of identical inverted L-shaped metallic structures placed perpendicular to the ground plane at −45° relative to the ME dipoles—which introduce an additional CP resonance through their mirror-symmetric configuration, thereby significantly broadening the axial ratio bandwidth. The filtering functionality is realized through a combination of symmetrical modifications: grid slots etched in the metallic ground plane and an open-circuited stub loaded on the microstrip feed line work in tandem to create two radiation nulls in the upper stopband, while the inherent symmetrical properties of the ME dipoles naturally produce a radiation null in the lower stopband. This comprehensive symmetry-based approach results in a well-balanced bandpass filtering response across a wide operating bandwidth. Experimental validation through prototype measurement confirms the effectiveness of the symmetric design with compact dimensions of 0.96λ0 × 0.55λ0 × 0.17λ0 (λ0 is the wavelength at the lowest operating frequency), demonstrating an impedance bandwidth of 66.4% (2.87–5.05 GHz), an AR bandwidth of 31.9% (3.32–4.58 GHz), an average passband gain of 5.5 dBi, and out-of-band suppression levels of 11.5 dB and 26.8 dB at the lower and upper stopbands, respectively, along with good filtering performance characterized by a gain-suppression index (GSI) of 0.93 and radiation skirt index (RSI) of 0.58. The proposed antenna is suitable for satellite communication terminals requiring wide AR bandwidth and strong interference rejection in L/S-bands. Full article
(This article belongs to the Special Issue Symmetry Study in Electromagnetism: Topics and Advances)
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26 pages, 8642 KiB  
Article
Ultra-High Strength and Specific Strength in Ti61Al16Cr10Nb8V5 Multi-Principal Element Alloy: Quasi-Static and Dynamic Deformation and Fracture Mechanisms
by Yang-Yu He, Zhao-Hui Zhang, Yi-Fan Liu, Yi-Chen Cheng, Xiao-Tong Jia, Qiang Wang, Jin-Zhao Zhou and Xing-Wang Cheng
Materials 2025, 18(14), 3245; https://doi.org/10.3390/ma18143245 - 10 Jul 2025
Viewed by 356
Abstract
This study investigates the deformation and fracture mechanisms of a Ti61Al16Cr10Nb8V5 multi-principal element alloy (Ti61V5 alloy) under quasi-static and dynamic compression. The alloy comprises an equiaxed BCC matrix (~35 μm) with uniformly dispersed nano-sized [...] Read more.
This study investigates the deformation and fracture mechanisms of a Ti61Al16Cr10Nb8V5 multi-principal element alloy (Ti61V5 alloy) under quasi-static and dynamic compression. The alloy comprises an equiaxed BCC matrix (~35 μm) with uniformly dispersed nano-sized B2 precipitates and a ~3.5% HCP phase along grain boundaries, exhibiting a density of 4.82 g/cm3, an ultimate tensile strength of 1260 MPa, 12.8% elongation, and a specific strength of 262 MPa·cm3/g. The Ti61V5 alloy exhibits a pronounced strain-rate-strengthening effect, with a strain rate sensitivity coefficient (m) of ~0.0088 at 0.001–10/s. Deformation activates abundant {011} and {112} slip bands in the BCC matrix, whose interactions generate jogs, dislocation dipoles, and loops, evolving into high-density forest dislocations and promoting screw-dominated mixed dislocations. The B2 phase strengthens the alloy via dislocation shearing, forming dislocation arrays, while the HCP phase enhances strength through a dislocation bypass mechanism. At higher strain rates (960–5020/s), m increases to ~0.0985. Besides {011} and {112}, the BCC matrix activates high-index slip planes {123}. Intensified slip band interactions generate dense jogs and forest dislocations, while planar dislocations combined with edge dislocation climb enable obstacle bypassing, increasing the fraction of edge-dominated mixed dislocations. The Ti61V5 alloy shows low sensitivity to adiabatic shear localization. Under forced shear, plastic-flow shear bands form first, followed by recrystallized shear bands formed through a rotational dynamic recrystallization mechanism. Microcracks initiate throughout the shear bands; during inward propagation, they may terminate upon encountering matrix microvoids or deflect and continue when linking with internal microcracks. Full article
(This article belongs to the Special Issue Fatigue, Damage and Fracture of Alloys)
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19 pages, 395 KiB  
Article
Assessment of Serum suPAR Levels in Patients with Group 1 and Group 4 Pulmonary Hypertension
by Abdullah Tunçez, Muhammed Ulvi Yalçın, Hüseyin Tezcan, Bülent Behlül Altunkeser, Bahadır Öztürk, Canan Aydoğan, Aslıhan Toprak, Onur Can Polat, Nazif Aygül, Kenan Demir, Kadri Murat Gürses, Yasin Özen, Fikret Akyürek and Hatice Betül Tunçez
J. Clin. Med. 2025, 14(13), 4671; https://doi.org/10.3390/jcm14134671 - 2 Jul 2025
Viewed by 367
Abstract
Background/Objectives: Pulmonary hypertension (PH) is a progressive disorder with high morbidity and mortality, partly driven by chronic inflammation. Soluble urokinase plasminogen activator receptor (suPAR) reflects immune activation. We evaluated whether suPAR is altered in Group 1 and Group 4 PH and its association [...] Read more.
Background/Objectives: Pulmonary hypertension (PH) is a progressive disorder with high morbidity and mortality, partly driven by chronic inflammation. Soluble urokinase plasminogen activator receptor (suPAR) reflects immune activation. We evaluated whether suPAR is altered in Group 1 and Group 4 PH and its association with clinical, echocardiographic, and laboratory parameters. Methods: We enrolled 44 PH patients (36 in Group 1, 8 in Group 4) and 45 healthy controls. All underwent clinical and echocardiographic assessments; right heart catheterization was performed in the PH patients. Serum suPAR was measured by ELISA. N-terminal pro B-type natriuretic peptide (NT-proBNP) and C-reactive protein (CRP) were also assessed. Results: The suPAR plasma levels in the PH group were between 23.91 and 960.8 pg/mL (median: 73.14 p25: 62.77, p75: 167.13). suPAR was significantly higher in PH versus controls (73.14 [62.77–167.13] vs. 65.52 [53.06–80.91] pg/mL; p = 0.012). In logistic regression, systolic blood pressure, erythrocyte sedimentation rate, NT-proBNP, and suPAR independently predicted PH. suPAR correlated negatively with six-minute walk distance (r = −0.310) and tricuspid annular plane systolic excursion (r = −0.295) but positively with systolic pulmonary artery pressure (r = 0.241). On multivariate analysis, six-minute walk distance was the only independent correlate of suPAR (p = 0.004). suPAR levels did not differ between Group 1 and Group 4 PH. Conclusions: suPAR is elevated in Group 1 and Group 4 PH and correlates with functional and echocardiographic indices of disease severity. Larger prospective studies are needed to determine suPAR’s role in diagnosis, risk stratification, and therapeutic decision-making. Full article
(This article belongs to the Section Cardiovascular Medicine)
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21 pages, 2973 KiB  
Article
Machine Learning Approach for Ground-Level Estimation of Electromagnetic Radiation in the Near Field of 5G Base Stations
by Oluwole John Famoriji and Thokozani Shongwe
Appl. Sci. 2025, 15(13), 7302; https://doi.org/10.3390/app15137302 - 28 Jun 2025
Viewed by 255
Abstract
Electromagnetic radiation measurement and management emerge as crucial factors in the economical deployment of fifth-generation (5G) infrastructure, as the new 5G network emerges as a network of services. By installing many base stations in strategic locations that operate in the millimeter-wave range, 5G [...] Read more.
Electromagnetic radiation measurement and management emerge as crucial factors in the economical deployment of fifth-generation (5G) infrastructure, as the new 5G network emerges as a network of services. By installing many base stations in strategic locations that operate in the millimeter-wave range, 5G services are able to meet serious demands for bandwidth. To evaluate the ground-plane radiation level of electromagnetics close to 5G base stations, we propose a unique machine-learning-based approach. Because a machine learning algorithm is trained by utilizing data obtained from numerous 5G base stations, it exhibits the capability to estimate the strength of the electric field effectively at every point of arbitrary radiation, while the base station generates a network and serves various numbers of 5G terminals running in different modes of service. The model requires different numbers of inputs, including the antenna’s transmit power, antenna gain, terminal service modes, number of 5G terminals, distance between the 5G terminals and 5G base station, and environmental complexity. Based on experimental data, the estimation method is both feasible and effective; the machine learning model’s mean absolute percentage error is about 5.89%. The degree of correctness shows how dependable the developed technique is. In addition, the developed approach is less expensive when compared to measurements taken on-site. The results of the estimates can be used to save test costs and offer useful guidelines for choosing the best location, which will make 5G base station electromagnetic radiation management or radio wave coverage optimization easier. Full article
(This article belongs to the Special Issue Recent Advances in Antennas and Propagation)
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28 pages, 3529 KiB  
Article
A Coverage-Based Cooperative Detection Method for CDUAV: Insights from Prediction Error Pipeline Modeling
by Jiong Li, Xianhai Feng, Yangchao He and Lei Shao
Drones 2025, 9(6), 397; https://doi.org/10.3390/drones9060397 - 27 May 2025
Viewed by 342
Abstract
To address the challenges of detection and acquisition caused by trajectory prediction errors during the midcourse–terminal guidance handover phase in cross-domain unmanned aerial vehicles (CDUAV), this study proposes a collaborative multi-interceptor detection coverage optimization method based on predictive error pipeline modeling. Firstly, we [...] Read more.
To address the challenges of detection and acquisition caused by trajectory prediction errors during the midcourse–terminal guidance handover phase in cross-domain unmanned aerial vehicles (CDUAV), this study proposes a collaborative multi-interceptor detection coverage optimization method based on predictive error pipeline modeling. Firstly, we employ nonlinear least squares to fit parameters for the motion model of CDUAV. By integrating error propagation theory, we derive a recursive expression for error pipelines under t-distribution and establish a parametric model for the target’s high-probability region (HPR). Next, we analyze target acquisition scenarios during guidance handover and reformulate the collaborative detection problem as a field-of-view (FOV) coverage optimization task on a two-dimensional detection plane. This framework incorporates the target HPR and the seeker detection FOV models, with an objective function defined for coverage optimization. Finally, inspired by wireless sensor network (WSN) coverage strategies, we implement the starfish optimization algorithm (SFOA) to enhance computational efficiency. Simulation results demonstrate that compared to Monte Carlo statistical methods, our parametric modeling approach reduces prediction error computation time from 15.82 s to 0.09 s while generating error pipeline envelopes with 99% confidence intervals, showing superior generalization capability. The proposed collaborative detection framework effectively resolves geometric coverage optimization challenges arising from mismatches between target HPR and FOV morphology, exhibiting rapid convergence and high computational efficiency. Full article
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16 pages, 12905 KiB  
Article
Experimental Investigation on Joint Effects in Rock Cutting with a Conical Pick Under Unrelieved Cutting Conditions
by Han-Eol Kim, Min-Seong Kim, Wan-Kyu Yoo, Chang-Yong Kim and Ji-Seok Yun
Appl. Sci. 2025, 15(10), 5578; https://doi.org/10.3390/app15105578 - 16 May 2025
Cited by 1 | Viewed by 336
Abstract
In this study, a series of unrelieved cutting tests was conducted to analyze the effect of joints on rock cutting using a conical pick. The tests were performed on jointed rock mass specimens with joint spacings (Js) of 30, 60, [...] Read more.
In this study, a series of unrelieved cutting tests was conducted to analyze the effect of joints on rock cutting using a conical pick. The tests were performed on jointed rock mass specimens with joint spacings (Js) of 30, 60, and 90 mm and at cutting depths of 3, 6, 9, and 12 mm. For each case, the distance between the cutting path and the joint plane (d) was varied from 0.1Js to 0.5Js. The cutting force decreased as the distance from the joint plane increased but reached the level observed in intact rock at the midpoint between adjacent joint planes (d = 0.5Js). Regardless of joint spacing, the cutting force reached its minimum when d was between 0.2Js and 0.3Js. The rock fragmentation zone extended beyond the joint plane when d was 0.1Js but became confined within the joint plane from around 0.2Js to 0.3Js. These results indicate that the influence of the joint is most pronounced within this range. Three types of crack propagation patterns were observed near the joint plane: (1) cracks that terminate at the joint along the shortest path, (2) cracks that pass through the joint and reach the opposite free surface, and (3) cracks that end at a free surface located just inside the joint plane. These observations suggest that the reduction in cutting force can be attributed to shorter crack propagation paths due to the presence of the joint. This study contributes to a better understanding of the cutting behavior of jointed rock masses when using a conical pick. Full article
(This article belongs to the Special Issue Novel Insights into Rock Mechanics and Geotechnical Engineering)
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14 pages, 1343 KiB  
Article
Comparing the Use of Transverse Abdominis Plane Block and Splash Block for Postoperative Pain Control in Dogs Undergoing Mastectomy—A Blinded Randomized Prospective Clinical Study
by Daniele Corona, Simone K. Ringer, Stefanie Keller, Iris M. Reichler, Regula Bettschart-Wolfensberger and Annette P. N. Kutter
Animals 2025, 15(9), 1323; https://doi.org/10.3390/ani15091323 - 2 May 2025
Viewed by 969
Abstract
To compare the use of postoperative analgesia for mastectomy, 44 dogs were randomly allocated to either the Splash treatment group (group A) or the Transverse Abdominis Plane block treatment group (TAP, group B). Following intramuscular (IM) premedication with pethidine (4 mg kg−1 [...] Read more.
To compare the use of postoperative analgesia for mastectomy, 44 dogs were randomly allocated to either the Splash treatment group (group A) or the Transverse Abdominis Plane block treatment group (TAP, group B). Following intramuscular (IM) premedication with pethidine (4 mg kg−1) and acepromazine (0.01 mg kg−1), anesthesia was induced with intravenous (IV) propofol and maintained with isoflurane by an anesthetist (DC) who was unaware of the treatment. In group A, ropivacaine 0.5% (2 mg kg−1) was administered prior to surgical wound closure. In group B, ropivacaine 0.5% (0.8–1 mg kg−1 per point) was administered by ultrasound-guided TAP block with two injection points per treated body side. At the end of the surgery, all dogs received pethidine (4 mg kg−1 IM), meloxicam (0.2 mg kg−1 IV), and acepromazine (0.005 mg kg−1 IV). The animals’ pain was assessed by the anesthetist, who remained unaware of the treatment type used, via the Short Form of the Glasgow Composite Pain Scale. When the pain scores were ≥6, methadone (0.2 mg kg−1 IV) and gabapentin (10 mg kg−1 per oral) were started. When the pain score remained ≥ 6, ketamine (1 mg kg−1 subcutaneously) was administered. The dogs in the TAP block group had lower postoperative pain scores 3–12 h after anesthesia administration was terminated and required significantly less rescue analgesia. Full article
(This article belongs to the Section Veterinary Clinical Studies)
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17 pages, 1026 KiB  
Article
Elevated Macrophage Migration Inhibitory Factor 1 Is Associated with Left and Right Ventricular Systolic Dysfunction in Heart Failure with Reduced Ejection Fraction
by Timea Magdolna Szabo, Mihály Vass, Márta Germán-Salló, Attila Frigy and Előd Ernő Nagy
Biomedicines 2025, 13(5), 1087; https://doi.org/10.3390/biomedicines13051087 - 30 Apr 2025
Viewed by 634
Abstract
Background/Objectives: Low-grade systemic inflammation, characteristic of heart failure (HF), is a nonspecific inflammatory syndrome that affects the entire body. Macrophage migration inhibitory factor 1 (MIF-1) is a pro-inflammatory cytokine, a key mediator of the innate immune response, and may serve as a [...] Read more.
Background/Objectives: Low-grade systemic inflammation, characteristic of heart failure (HF), is a nonspecific inflammatory syndrome that affects the entire body. Macrophage migration inhibitory factor 1 (MIF-1) is a pro-inflammatory cytokine, a key mediator of the innate immune response, and may serve as a potential biomarker of monocyte homing and activation in HF with reduced and mildly reduced ejection fraction (HFrEF, HFmrEF). Methods: We evaluated 70 hemodynamically stable patients with left ventricular EF (LVEF) < 50% by means of echocardiography and blood sampling. Results: We report significant correlations between MIF-1, LVEF (r = −0.33, p = 0.005), LV global longitudinal strain (LVGLS, r = 0.41, p = 0.0004), and tricuspid annular plane systolic excursion (TAPSE, r = −0.37, p = 0.001). MIF-1 levels in HFrEF patients were relatively higher, but not significantly different from those observed in HFmrEF. MIF-1 showed significant associations with TAPSE to systolic pulmonary artery pressure ratio (TAPSE/sPAP, p < 0.0001). Also, patients with TAPSE/sPAP < 0.40 mm/mmHg had significantly higher levels of MIF-1 (p = 0.009). Moreover, ischemic cardiomyopathy (ICM) was more frequent in patients with MIF-1 concentrations above 520 pg/mL (57.1% MIF-1hi vs. 28.6% MIF-1lo, p = 0.029). In terms of congestion, MIF-1 showed significant associations with the presence of peripheral edema (p = 0.007), but none was found with self-reported dyspnea (p = 0.307) and New York Heart Association (NYHA) class (p = 0.486). Also, no relationship was reported with N-terminal pro-B-type natriuretic peptide concentrations (NT-proBNP, r = 0.14, p = 0.263). However, the six-minute walk distance was greater in individuals in the MIF-1lo group when compared to those in the MIF-1hi group (404.0 ± 127.4 vs. 324.8 ± 124.1 m, p = 0.010). Conclusions: Beyond identifying inflammatory biomarkers related to disease severity, linking MIF-1 to various pathophysiological mechanisms may highlight the active involvement of the monocyte-macrophage system in HF. This system holds notable significance in congestion-related conditions, acting as a major source of reactive oxygen species that perpetuate inflammation. Full article
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6 pages, 228 KiB  
Article
Stellar Wind Parameters of Massive Stars in Accretion-Powered High-Mass X-Ray Binary Pulsars
by Nina Beskrovnaya, Nazar Ikhsanov and Vitaliy Kim
Galaxies 2025, 13(2), 37; https://doi.org/10.3390/galaxies13020037 - 5 Apr 2025
Viewed by 383
Abstract
The process of mass exchange between the components of High-Mass X-ray Binary (HMXB) systems with neutron stars undergoing wind-fed accretion is discussed. The X-ray luminosity of these systems allows us to evaluate the mass capture rate by the neutron star from the stellar [...] Read more.
The process of mass exchange between the components of High-Mass X-ray Binary (HMXB) systems with neutron stars undergoing wind-fed accretion is discussed. The X-ray luminosity of these systems allows us to evaluate the mass capture rate by the neutron star from the stellar wind of its massive companion and set limits on the relative velocity between the neutron star and the wind. We found that the upper limit to the wind velocity in the orbital plane during the high state of the X-ray source is in the range of 120–1000 kms1, which is by a factor of 2–4 lower than both the terminal wind velocity and the speed of the wind flowing out from the polar regions of massive stars for all the objects under investigation. This finding is valid not only for the systems with Be stars, but also for the systems in which the optical components do not exhibit the Be phenomenon. We also show that the lower limit to the radial wind velocity in these systems can unlikely be smaller than a few percent of the orbital velocity of the neutron star. This provides us with a new constraint on the mass transfer process in the outflowing disks of Be-type stars. Full article
(This article belongs to the Special Issue Circumstellar Matter in Hot Star Systems)
12 pages, 1515 KiB  
Article
Early Postoperative Gait Analysis in Elderly Patients Following Hip Fracture Surgery
by Gereon Anton Hecht, Rachel Senden, Rik Marcellis, Matthias Mertes, Paul Willems, Kenneth Meijer, Martijn Poeze and Taco J. Blokhuis
Sensors 2025, 25(6), 1888; https://doi.org/10.3390/s25061888 - 18 Mar 2025
Viewed by 891
Abstract
Hip fractures in elderly patients significantly reduce independence and quality of life. Early postoperative gait performance remains poorly understood, particularly regarding differences between surgical treatments, such as proximal femur nailing and hemiarthroplasty. Identifying gait alterations early in rehabilitation could optimize clinical interventions. This [...] Read more.
Hip fractures in elderly patients significantly reduce independence and quality of life. Early postoperative gait performance remains poorly understood, particularly regarding differences between surgical treatments, such as proximal femur nailing and hemiarthroplasty. Identifying gait alterations early in rehabilitation could optimize clinical interventions. This prospective observational cohort study included 40 elderly patients hospitalized after acute hip fracture surgery. Relative peak force and step duration were assessed using the ambulant pressure biofeedback system during postoperative mobilization. Additionally, three-dimensional gait analysis evaluated spatiotemporal parameters and sagittal plane kinematics of the hip, knee, and ankle. Results demonstrated significant improvements in median peak force (45.32% to 70.00%, (p < 0.001)) and median step duration (2.96 s to 137 s, (p < 0.001)) at the end of the hospitalization period. No significant differences in step duration and peak force were observed between the different surgical procedures, proximal femur nail, and hemiarthroplasty. Three-dimensional gait analysis showed significantly reduced hip extension during terminal stance in the operated leg compared to the healthy leg. These findings highlight the utility of biofeedback systems for monitoring early rehabilitation progress and emphasize the importance of 3D gait analysis in identifying early postoperative gait deficits. Targeted interventions during hospitalization could enhance functional recovery and improve patient outcomes. Full article
(This article belongs to the Section Biomedical Sensors)
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10 pages, 426 KiB  
Review
The Blue Supergiant Problem and the Main-Sequence Width
by Jorick S. Vink and Rene D. Oudmaijer
Galaxies 2025, 13(2), 19; https://doi.org/10.3390/galaxies13020019 - 6 Mar 2025
Viewed by 752
Abstract
Using Gaia DR3 we derive new distances and luminosities for a sample of Galactic B supergiants which were thought to be post main-sequence (MS) objects from their HR diagram location beyond the terminal-age MS (TAMS). When applying the newer Gaia distances in addition [...] Read more.
Using Gaia DR3 we derive new distances and luminosities for a sample of Galactic B supergiants which were thought to be post main-sequence (MS) objects from their HR diagram location beyond the terminal-age MS (TAMS). When applying the newer Gaia distances in addition to enhanced amounts of core-boundary mixing, aka convective overshooting, we show that these Galactic B supergiants are likely enclosed within the MS band, indicating an evolutionary stage of steady core hydrogen burning. We discuss the importance of considering enhanced overshooting and how vectors in the mass-luminosity plane (ML-plane) can be used to disentangle the effects of wind mass loss from interior mixing. We finish with the key message that any proposed solution to the BSG problem should consider not only an explanation for the sheer number of B supergiants inside the Hertzsprung gap, but should at the same time also account for the steep drop in rotation rates identified at spectral type B1—corresponding to an effective temperature of ∼21 kK, and for which two distinct families of solutions have been proposed. Full article
(This article belongs to the Special Issue Circumstellar Matter in Hot Star Systems)
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19 pages, 2729 KiB  
Article
Social Image Security with Encryption and Watermarking in Hybrid Domains
by Conghuan Ye, Shenglong Tan, Jun Wang, Li Shi, Qiankun Zuo and Wei Feng
Entropy 2025, 27(3), 276; https://doi.org/10.3390/e27030276 - 6 Mar 2025
Cited by 6 | Viewed by 951
Abstract
In this digital era, social images are the most vital information carrier on multimedia social platforms. More and more users are interested in sharing social images with mobile terminals on multimedia social platforms. Social image sharing also faces potential risks from malicious use, [...] Read more.
In this digital era, social images are the most vital information carrier on multimedia social platforms. More and more users are interested in sharing social images with mobile terminals on multimedia social platforms. Social image sharing also faces potential risks from malicious use, such as illegal sharing, piracy, and misappropriation. This paper mainly concentrates on secure social image sharing. To address how to share social images in a safe way, a social image security scheme is proposed. The technology addresses the social image security problem and the active tracing problem. First, discrete wavelet transform (DWT) is performed directly from the JPEG image. Then, the high-bit planes of the LL, LH, and HL are permuted with cellular automation (CA), bit-XOR, and singular value decomposition (SVD) computing, and their low-bit planes are chosen to embed a watermark. In the end, the encrypted and watermarked image is again permuted with cellular automation in the discrete cosine transform (DCT) domain. Experimental results and security analysis show that the social image security method not only has good performance in robustness, security, and time complexity but can also actively trace the illegal distribution of social images. The proposed social image security method can provide double-level security for multimedia social platforms. Full article
(This article belongs to the Section Multidisciplinary Applications)
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14 pages, 1917 KiB  
Article
Sagittal Plane Kinematic Deviations and Spatio-Temporal Gait Characteristics in Children with Idiopathic Toe Walking: A Comparative Analysis Using Statistical Parametric Mapping
by Rocio Pozuelo-Calvo, Almudena Serrano-Garcia, Yolanda Archilla-Bonilla, Angel Ruiz-Zafra, Manuel Noguera-Garcia, Kawtar Benghazi-Akhlaki, Miguel Membrilla-Mesa, Carla DiCaudo and Jose Heredia-Jimenez
Diagnostics 2025, 15(5), 575; https://doi.org/10.3390/diagnostics15050575 - 27 Feb 2025
Viewed by 921
Abstract
Background/Objectives: Idiopathic Toe Walking (ITW) is a pediatric gait disorder characterized by persistent toe-to-heel ambulation in the absence of neurological, orthopedic, or developmental abnormalities. While spatio-temporal parameters often remain within normal ranges, subtle but clinically significant kinematic deviations may underlie compensatory mechanisms [...] Read more.
Background/Objectives: Idiopathic Toe Walking (ITW) is a pediatric gait disorder characterized by persistent toe-to-heel ambulation in the absence of neurological, orthopedic, or developmental abnormalities. While spatio-temporal parameters often remain within normal ranges, subtle but clinically significant kinematic deviations may underlie compensatory mechanisms that sustain gait functionality. This study aims to evaluate spatio-temporal and sagittal plane kinematic differences between children with ITW and typically developing peers using Statistical Parametric Mapping (SPM). Methods: A cohort of 30 children with ITW and 30 typically developing peers aged 6–12 years participated in this study. Spatio-temporal variables, including step length, cadence, stride length, walking speed, single support phase, and swing phase, were analyzed using a three-dimensional motion capture system. Sagittal plane kinematics of the pelvis, hip, knee, and ankle were compared between groups using SPM to identify significant deviations across the gait cycle. Results: Significant differences were identified in the single support and swing phases, with higher values observed in the ITW group (p < 0.05). Sagittal plane kinematics revealed a consistent reduction in anterior pelvic tilt (p = 0.002), reduced hip and knee flexion during stance and swing phases (p < 0.001), and excessive ankle plantarflexion during early stance and terminal swing phases (p < 0.001). The plantarflexion observed at the end of the gait cycle corresponded to early gait phases due to methodological considerations of the coordinate-based event detection algorithm. Conclusions: Children with ITW demonstrate distinct spatio-temporal adaptations, including increased single support and swing phases, along with reduced walking velocity compared to typically developing peers. These findings, coupled with significant sagittal plane kinematic deviations, suggest altered neuromuscular control and joint mechanics. These insights highlight the importance of detailed kinematic analyses to identify biomechanical deficits and inform targeted interventions. Future research should explore the long-term musculoskeletal consequences of these deviations and optimize therapeutic strategies, such as physical therapy and orthotic interventions, to improve gait functionality and quality of life. Full article
(This article belongs to the Section Clinical Diagnosis and Prognosis)
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18 pages, 13167 KiB  
Article
Research on Low-Profile Directional Flexible Antenna with 3D Coplanar Waveguide for Partial Discharge Detection
by Yan Mi, Wentao Liu, Yiqin Peng, Lei Deng, Benxiang Shu, Xiaopeng Wang and Songyuan Li
Micromachines 2025, 16(3), 253; https://doi.org/10.3390/mi16030253 - 24 Feb 2025
Viewed by 1393
Abstract
Due to the challenges in antenna installation and detection performance caused by metal obstruction along the propagation path at a Gas-Insulated Switchgear (GIS) cable terminal, as well as the adverse effects of environmental interference on the detection of partial discharge (PD) by existing [...] Read more.
Due to the challenges in antenna installation and detection performance caused by metal obstruction along the propagation path at a Gas-Insulated Switchgear (GIS) cable terminal, as well as the adverse effects of environmental interference on the detection of partial discharge (PD) by existing flexible antennas, this paper proposes a directional flexible antenna design to mitigate these issues and improve detection performance. The proposed design employs a coplanar waveguide (CPW)-fed monopole antenna structure, where the grounding plane is extended to the back of the antenna to enhance directional reception. The designed flexible antenna measures 88.5 × 70 × 20 mm, and its low-profile design allows it to be easily mounted on the outer wall of the epoxy sleeve at the GIS cable terminal. The measurement results show that the flexible antenna has a Voltage Standing Wave Ratio (VSWR) of less than 2 in the 0.541–3 GHz frequency range. It also maintains stable impedance characteristics across various bending radii, with an average effective height of 10.79 mm in the 0.3–1.5 GHz frequency range. A GIS cable terminal PD experimental platform was established, and the experimental results demonstrate that the bending has minimal impact on the detection performance of the flexible antenna, which can cover the detection range of the GIS cable terminal; metal obstruction significantly impacts the PD signal amplitude, and the designed flexible antenna is suitable for detecting PDs in confined spaces with metal obstruction. Full article
(This article belongs to the Section E:Engineering and Technology)
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