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Search Results (408)

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20 pages, 5486 KiB  
Article
SE-TransUNet-Based Semantic Segmentation for Water Leakage Detection in Tunnel Secondary Linings Amid Complex Visual Backgrounds
by Renjie Song, Yimin Wu, Li Wan, Shuai Shao and Haiping Wu
Appl. Sci. 2025, 15(14), 7872; https://doi.org/10.3390/app15147872 - 14 Jul 2025
Viewed by 182
Abstract
Traditional manual inspection methods for tunnel lining leakage are subjective and inefficient, while existing models lack sufficient recognition accuracy in complex scenarios. An intelligent leakage identification model adaptable to complex backgrounds is therefore needed. To address these issues, a Vision Transformer (ViT) was [...] Read more.
Traditional manual inspection methods for tunnel lining leakage are subjective and inefficient, while existing models lack sufficient recognition accuracy in complex scenarios. An intelligent leakage identification model adaptable to complex backgrounds is therefore needed. To address these issues, a Vision Transformer (ViT) was integrated into the UNet architecture, forming an SE-TransUNet model by incorporating SE-Block modules at skip connections between the encoder-decoder and the ViT output. Using a hybrid leakage dataset partitioned by k-fold cross-validation, the roles of SE-Block and ViT modules were examined through ablation experiments, and the model’s attention mechanism for leakage features was analyzed via Score-CAM heatmaps. Results indicate: (1) SE-TransUNet achieved mean values of 0.8318 (IoU), 0.8304 (Dice), 0.9394 (Recall), 0.8480 (Precision), 0.9733 (AUC), 0.8562 (MCC), 0.9218 (F1-score), and 6.53 (FPS) on the hybrid dataset, demonstrating robust generalization in scenarios with dent shadows, stain interference, and faint leakage traces. (2) Ablation experiments confirmed both modules’ necessity: The baseline model’s IoU exceeded the variant without the SE module by 4.50% and the variant without both the SE and ViT modules by 7.04%. (3) Score-CAM heatmaps showed the SE module broadened the model’s attention coverage of leakage areas, enhanced feature continuity, and improved anti-interference capability in complex environments. This research may provide a reference for related fields. Full article
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17 pages, 373 KiB  
Review
Innovations in Stress Urinary Incontinence: A Narrative Review
by Tamas Szabo, Melinda-Ildiko Mitranovici, Liviu Moraru, Dan Costachescu, Laura Georgiana Caravia, Elena Bernad, Viviana Ivan, Adrian Apostol, Mihai Munteanu and Lucian Puscasiu
Medicina 2025, 61(7), 1272; https://doi.org/10.3390/medicina61071272 - 14 Jul 2025
Viewed by 311
Abstract
Urinary incontinence is characterized by the involuntary leakage of urine. The primary cause of stress urinary incontinence in women is the weakening of the pelvic floor muscles. Stress urinary incontinence (SUI) is a significant global health problem that impacts mainly middle-aged women, with [...] Read more.
Urinary incontinence is characterized by the involuntary leakage of urine. The primary cause of stress urinary incontinence in women is the weakening of the pelvic floor muscles. Stress urinary incontinence (SUI) is a significant global health problem that impacts mainly middle-aged women, with a severe impact on their quality of life. Traditional diagnostic methods and treatments often fail, although technological innovations have improved diagnostic accuracy, such as specific questionnaires or transperineal ultrasound. While medical therapies and surgical procedures are continuously being developed, controversies about the correct choices regarding diagnostic and treatment methods continue to exist. The aim of our review was to identify the innovative diagnostic tools and effective treatment procedures for SUI. A narrative review was conducted due to the heterogeneity of the studies. New methods for diagnosis and treatment have gained ground, and we have covered them in our review; however, the field continues to expand. A personalized approach to diagnosis is also a requirement because of the limitations of conventional urodynamic studies, and we emphasize the importance of such personalization in enhancing clinical decision making. Future medical strategies that combine both preventive and therapeutic care are desirable. Newer technologies were brought to light in this review, including stem cell therapy and laser therapy. Full article
(This article belongs to the Special Issue New Insights into Gynecological Disease)
28 pages, 7517 KiB  
Review
A Review of the Research Progress on Optical Fiber Sensors Based on C-Type Structures
by Zhijun Gao, Zhenbo Li and Yu Ying
Photonics 2025, 12(7), 695; https://doi.org/10.3390/photonics12070695 - 10 Jul 2025
Viewed by 348
Abstract
With the continuous advancement of optical fiber micromachining technology, C-type optical fibers have demonstrated significant potential in the field of optical fiber sensing. By partially or completely removing specific regions of the cladding, a “leakage window” is created, enabling interaction between the optical [...] Read more.
With the continuous advancement of optical fiber micromachining technology, C-type optical fibers have demonstrated significant potential in the field of optical fiber sensing. By partially or completely removing specific regions of the cladding, a “leakage window” is created, enabling interaction between the optical field and external substances. This structure has facilitated the development of various sensors. This paper reviews recent progress in the research and applications of C-type optical fibers in optical sensing. Based on sensing principles and application scenarios, C-type optical fiber sensors can be categorized into two main types: interferometric and photonic crystal types. This article discusses the fundamental operating principles and structural characteristics of each type, and provides a detailed comparison of their respective advantages and disadvantages. Studies have shown that sensors based on C-type fiber structures offer notable benefits such as simple fabrication, excellent mechanical performance, strong anti-interference capability, and high sensitivity. Therefore, they hold great promise for applications in intelligent monitoring, environmental detection, and healthcare. Finally, this review outlines future research directions for C-type fiber sensors. As technology continues to evolve, future studies are expected to focus on improving sensor stability, expanding application scenarios, and addressing challenges in current fabrication techniques. Full article
(This article belongs to the Section Optoelectronics and Optical Materials)
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62 pages, 4192 KiB  
Review
Advancements in Magnetorheological Foams: Composition, Fabrication, AI-Driven Enhancements and Emerging Applications
by Hesamodin Khodaverdi and Ramin Sedaghati
Polymers 2025, 17(14), 1898; https://doi.org/10.3390/polym17141898 - 9 Jul 2025
Viewed by 461
Abstract
Magnetorheological (MR) foams represent a class of smart materials with unique tunable viscoelastic properties when subjected to external magnetic fields. Combining porous structures with embedded magnetic particles, these materials address challenges such as leakage and sedimentation, typically encountered in conventional MR fluids while [...] Read more.
Magnetorheological (MR) foams represent a class of smart materials with unique tunable viscoelastic properties when subjected to external magnetic fields. Combining porous structures with embedded magnetic particles, these materials address challenges such as leakage and sedimentation, typically encountered in conventional MR fluids while offering advantages like lightweight design, acoustic absorption, high energy harvesting capability, and tailored mechanical responses. Despite their potential, challenges such as non-uniform particle dispersion, limited durability under cyclic loads, and suboptimal magneto-mechanical coupling continue to hinder their broader adoption. This review systematically addresses these issues by evaluating the synthesis methods (ex situ vs. in situ), microstructural design strategies, and the role of magnetic particle alignment under varying curing conditions. Special attention is given to the influence of material composition—including matrix types, magnetic fillers, and additives—on the mechanical and magnetorheological behaviors. While the primary focus of this review is on MR foams, relevant studies on MR elastomers, which share fundamental principles, are also considered to provide a broader context. Recent advancements are also discussed, including the growing use of artificial intelligence (AI) to predict the rheological and magneto-mechanical behavior of MR materials, model complex device responses, and optimize material composition and processing conditions. AI applications in MR systems range from estimating shear stress, viscosity, and storage/loss moduli to analyzing nonlinear hysteresis, magnetostriction, and mixed-mode loading behavior. These data-driven approaches offer powerful new capabilities for material design and performance optimization, helping overcome long-standing limitations in conventional modeling techniques. Despite significant progress in MR foams, several challenges remain to be addressed, including achieving uniform particle dispersion, enhancing viscoelastic performance (storage modulus and MR effect), and improving durability under cyclic loading. Addressing these issues is essential for unlocking the full potential of MR foams in demanding applications where consistent performance, mechanical reliability, and long-term stability are crucial for safety, effectiveness, and operational longevity. By bridging experimental methods, theoretical modeling, and AI-driven design, this work identifies pathways toward enhancing the functionality and reliability of MR foams for applications in vibration damping, energy harvesting, biomedical devices, and soft robotics. Full article
(This article belongs to the Section Polymer Composites and Nanocomposites)
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26 pages, 808 KiB  
Review
A Review of Formulation Strategies for Cyclodextrin-Enhanced Solid Lipid Nanoparticles (SLNs) and Nanostructured Lipid Carriers (NLCs)
by Tarek Alloush and Burcu Demiralp
Int. J. Mol. Sci. 2025, 26(13), 6509; https://doi.org/10.3390/ijms26136509 - 6 Jul 2025
Viewed by 763
Abstract
The advancement of efficient drug delivery systems continues to pose a significant problem in pharmaceutical sciences, especially for compounds with limited water solubility. Lipid-based systems, including solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs), have emerged as viable options owing to their [...] Read more.
The advancement of efficient drug delivery systems continues to pose a significant problem in pharmaceutical sciences, especially for compounds with limited water solubility. Lipid-based systems, including solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs), have emerged as viable options owing to their biocompatibility, capability to safeguard labile chemicals, and potential for prolonged release. Nonetheless, the encapsulation efficiency (EE) and release dynamics of these carriers can be enhanced by including cyclodextrins (CDs)—cyclic oligosaccharides recognized for their ability to form inclusion complexes with hydrophobic compounds. This article offers an extensive analysis of CD-modified SLNs and NLCs as multifunctional drug delivery systems. The article analyses the fundamental principles of these systems, highlighting the pre-complexation of the drug with cyclodextrins before lipid incorporation, co-encapsulation techniques, and surface adsorption after formulation. Attention is concentrated on the physicochemical interactions between cyclodextrins and lipid matrices, which influence essential factors such as particle size, encapsulation efficiency, and colloidal stability. The review includes characterization techniques, such as particle size analysis, zeta potential measurement, drug release studies, and Fourier-transform infrared spectroscopy (FT-IR)/Nuclear Magnetic Resonance (NMR) analyses. The study highlights the application of these systems across many routes of administration, including oral, topical, and mucosal, illustrating their adaptability and potential for targeted delivery. The review outlines current formulation challenges, including stability issues, drug leakage, and scalability concerns, and proposes solutions through advanced approaches, such as stimuli-responsive release mechanisms and computer modeling for system optimization. The study emphasizes the importance of regulatory aspects and outlines future directions in the development of CD-lipid hybrid nanocarriers, showcasing its potential to revolutionize the delivery of poorly soluble drugs. Full article
(This article belongs to the Special Issue Research on Cyclodextrin)
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23 pages, 1742 KiB  
Article
Regional Disparities, Spatial Effects, and the Dynamic Evolution of Distorted Energy Prices in China
by Zhiyuan Gao, Ziying Jia and Yu Hao
Energies 2025, 18(13), 3465; https://doi.org/10.3390/en18133465 - 1 Jul 2025
Viewed by 305
Abstract
The distortion of energy prices has become an important obstacle to the high-quality development of China’s economy. Moreover, energy price distortions are not merely a domestic issue. They may trigger carbon leakage by diverting emissions-intensive production to countries with cheaper energy. Although the [...] Read more.
The distortion of energy prices has become an important obstacle to the high-quality development of China’s economy. Moreover, energy price distortions are not merely a domestic issue. They may trigger carbon leakage by diverting emissions-intensive production to countries with cheaper energy. Although the existing literature has extensively examined the effects of energy price distortions, two significant research gaps remain. First, most studies treat energy price distortions merely as an influencing factor, lacking a systematic analysis that places it at the core. Second, the spatial correlation characteristics of energy price distortions are often overlooked. This study measures the degree of energy price distortions across Chinese provinces from 2000 to 2022 and employs methods such as the Global Moran’s I, Local Moran’s I, and kernel density estimation to systematically analyze the spatial correlation, spatial distribution of coordination indices, and dynamic evolution patterns of these distortions. The results reveal that: (1) the overall degree of energy price distortions in China exhibited a trend of rising first and then declining, with significant regional disparities; (2) the regional gap followed an “expansion-contraction” trajectory; (3) there is notable spatial autocorrelation, with high-distortion areas concentrated in Northeast China, the middle reaches of the Yellow River, and Northwest China; and (4) the dynamic evolution suggests that distortion levels in high- and medium-value regions may continue to decline, while those in low-value regions may increase. This study fills a critical gap in the systematic spatial analysis of energy price distortions and provides new empirical evidence and policy insights for advancing market-oriented reforms in energy markets. Full article
(This article belongs to the Special Issue Environmental Sustainability and Energy Economy)
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13 pages, 1875 KiB  
Article
Quantitative Characterization of Carbonate Mineralogy in Lake Yangzong Sediments Using XRF-Derived Calcium Signatures and Inorganic Carbon Measurements
by Huayong Li, Lizeng Duan, Junhui Mo, Jungang Lin, Huayu Li, Han Wang, Jingwen Wu, Qifa Sun and Hucai Zhang
Water 2025, 17(13), 1949; https://doi.org/10.3390/w17131949 - 29 Jun 2025
Viewed by 262
Abstract
The carbonate content serves as a fundamental proxy in lacustrine sediments for reconstructing palaeoclimate and environmental changes. Although multiple analytical techniques exist for its quantification, systematic comparisons between different methodologies and the precise identification of carbonate mineralogy are still needed. In this study, [...] Read more.
The carbonate content serves as a fundamental proxy in lacustrine sediments for reconstructing palaeoclimate and environmental changes. Although multiple analytical techniques exist for its quantification, systematic comparisons between different methodologies and the precise identification of carbonate mineralogy are still needed. In this study, a 1020 cm continuous sediment core (YZH-1) from Lake Yangzong in Yunnan Province was employed. Initially, the semi-quantitative calcium (Ca) concentration was obtained via X-ray fluorescence (XRF) core scanning. Subsequently, the total inorganic carbon (TIC) content was determined using both the loss on ignition (LOI) and gasometric (GM) methods to evaluate methodological discrepancies and potential biases. Furthermore, a quantitative regression model was developed to estimate carbonate abundance based on the relationship between XRF-derived Ca data and the analytically determined carbonate content. A comparative analysis revealed a strong positive correlation (r = 0.97) between LOI and GM measurements, though LOI-derived values are systematically elevated by 2.6% on average. This overestimation likely stems from the thermal decomposition of non-carbonate minerals during LOI analysis. Conversely, GM measurements exhibit a ~5% underestimation relative to certified reference materials, attributable to instrumental limitations such as gas leakage. Strong covariation (r = 0.92) between XRF-Ca intensities and the TIC content indicates that carbonate minerals in Lake Yangzong sediments predominantly consist of calcite. A transfer function was established to convert XRF-Ca scanning data into absolute Ca concentrations, leveraging the robust Ca-TIC relationship. The proposed quantification model demonstrates high reliability when applied to standardized XRF-Ca datasets, offering a practical tool for paleolimnological studies in similar geological settings. Full article
(This article belongs to the Section Hydrology)
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11 pages, 672 KiB  
Article
A Multicenter, Randomized, Single-Blind Trial Evaluating a Multi-Porous Urethral Catheter with Continuous Local Ropivacaine Infusion for the Reduction of Postoperative Catheter-Related Bladder Discomfort
by Sangmin Lee, Kwang Taek Kim, Tae Beom Kim, Kyung Jin Chung, Kookjin Huh, Hwanik Kim and Sang Hoon Song
J. Clin. Med. 2025, 14(12), 4215; https://doi.org/10.3390/jcm14124215 - 13 Jun 2025
Viewed by 379
Abstract
Background/Objectives: Catheter-related bladder discomfort (CRBD) commonly occurs in patients undergoing urologic surgery and significantly affects patient comfort and recovery. We evaluated the efficacy and safety of continuous local ropivacaine infusion using a specialized multi-porous urethral catheter in reducing postoperative CRBD. Methods: This [...] Read more.
Background/Objectives: Catheter-related bladder discomfort (CRBD) commonly occurs in patients undergoing urologic surgery and significantly affects patient comfort and recovery. We evaluated the efficacy and safety of continuous local ropivacaine infusion using a specialized multi-porous urethral catheter in reducing postoperative CRBD. Methods: This multicenter, prospective, randomized, single-blind trial enrolled 136 male patients undergoing short-term catheterization after urologic surgery. Participants were randomized into three groups—a control group receiving saline infusion, Group 1 receiving 0.5% ropivacaine at 1 mL/h, and Group 2 receiving 0.5% ropivacaine at 2 mL/h—for up to 48 h via a multi-porous urethral catheter. The primary outcome was the incidence of CRBD at 24 h postoperatively. Secondary outcomes included changes in urethral pain assessed by a visual analog scale (VAS), urinary symptom scores, complication rates, and patient-reported catheter inconvenience and reuse intention using Likert scales. Results: The incidence of CRBD was significantly lower in Group 1 (19.6%) and Group 2 (11.1%) compared to the control group (44.4%; p = 0.001), demonstrating a clear dose–response relationship. Changes in urethral pain scores (VAS) from baseline were significantly lower in the ropivacaine groups compared to the control (p = 0.023). Complication rates were similar among groups (control 13.3%, Group 1 6.5%, Group 2 15.6%; p = 0.378), although catheter leakage occurred more frequently in Group 2, without statistical significance (p = 0.122). Conclusions: Continuous local ropivacaine infusion using a multi-porous urethral catheter effectively reduces the incidence of postoperative CRBD without increasing side effects. This approach may improve patient comfort during perioperative catheter management. Full article
(This article belongs to the Section Nephrology & Urology)
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19 pages, 11510 KiB  
Article
Analytic Continual Learning-Based Non-Intrusive Load Monitoring Adaptive to Diverse New Appliances
by Chaofan Lan, Qingquan Luo, Tao Yu, Minhang Liang, Wenlong Guo and Zhenning Pan
Appl. Sci. 2025, 15(12), 6571; https://doi.org/10.3390/app15126571 - 11 Jun 2025
Viewed by 404
Abstract
Non-intrusive load monitoring (NILM) provides a cost-effective solution for smart services across numerous appliances by inferring appliance-level information from mains electrical measurements. With the rapid growth in appliance diversity, continual learning that adapts to new appliances while retaining knowledge of previously learned appliances [...] Read more.
Non-intrusive load monitoring (NILM) provides a cost-effective solution for smart services across numerous appliances by inferring appliance-level information from mains electrical measurements. With the rapid growth in appliance diversity, continual learning that adapts to new appliances while retaining knowledge of previously learned appliances is of great interest. However, existing methods can handle only a few new appliance types and suffer from high computational complexity and data leakage risks. Therefore, an analytic continual learning-based (ACL) NILM method is proposed. The method employs a lightweight model that is constructed with dual output branches using depthwise separable convolution for load identification and novelty detection. Meanwhile, a supervised contrastive learning strategy is applied to enhance the distinctiveness among appliance types in the feature extraction module. When the novelty detection branch determines that new data need to be learned, the parameters of the dual branches are updated by recursively calculating the analytical solution using only the current data. Experiments on four public datasets demonstrate superior performance on pre-collected appliances with lower computational effort. It also significantly outperforms existing methods during the continual learning process, as the number of appliance types increases to 56. The practicality of the proposed method is validated through a real-world application on an STM32F407-based smart socket. Full article
(This article belongs to the Topic Smart Electric Energy in Buildings)
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20 pages, 1462 KiB  
Systematic Review
A Systematic Review and Meta-Analysis on the Efficacy and Safety of Concomitant Laparoscopic Cholecystectomy and Sleeve Gastrectomy in Patients with Morbid Obesity
by Walid M. Abd El Maksoud, Khaled S. Abbas, Fahad S. Al Amri, Hassan A. Alzahrani, Abdullah Dalboh, Marei H. Alshandeer, Maha A. Alghamdi, Fadhl H. Yahya, Abdullrahman M. Bawahab, Haytham M. Fayed, Ahmad Jebril M. Bosaily and Mohammed A. Bawahab
J. Clin. Med. 2025, 14(12), 4108; https://doi.org/10.3390/jcm14124108 - 10 Jun 2025
Viewed by 481
Abstract
Background/Objectives: Rapid weight loss after bariatric surgery is linked to a higher risk of symptomatic gallstone disease, which could require a cholecystectomy. This meta-analysis aimed to assess the efficacy and safety of conducting laparoscopic cholecystectomy concurrently with sleeve gastrectomy in morbid obese patients. [...] Read more.
Background/Objectives: Rapid weight loss after bariatric surgery is linked to a higher risk of symptomatic gallstone disease, which could require a cholecystectomy. This meta-analysis aimed to assess the efficacy and safety of conducting laparoscopic cholecystectomy concurrently with sleeve gastrectomy in morbid obese patients. Methods: Scopus, PubMed, ProQuest, Web of Science, and Google Scholar were searched for this review. Quality assessment was conducted using the Newcastle-Ottawa Scale for observational studies and ROB2 for randomized clinical trials. Eight of thirteen studies were high-quality. Pooling for BMI difference and LOS was used to measure efficacy, and the pooled proportion was utilized to assess safety through bleeding, wound infection, and leakage. Heterogeneity was explained via leave-one-out analysis and meta-regression. Results: The pooled standardized mean difference in BMI peri-operation was 3.26 (95% CI: 2.51–4.01, p < 0.01), where the age and initial BMI explained 98% of the heterogeneity through meta-regression. The pooled mean of LOS was 3.18 days (95% CI: 2.23–4.14, I2 = 99%, p < 0.001), where age explained 33.22% of the heterogeneity through meta-regression. The pooled proportion of bleeding was 0.03 (95% CI: 0.02–0.04, I2 = 2%, p = 0.42). The pooled wound infection was 0.04 (95% CI: 0.02–0.08, I2 = 80%, p < 0.001), where age accounted for 99% of the heterogeneity. The pooled biliary/gastric leakage was 0.02 (95% CI: 0.01–0.05, I2 = 0, p = 0.52). Conclusions: These findings indicate that the combined procedures can be executed with an acceptable safety profile. The heterogeneity in outcomes underscores the necessity of personalized patient care, standardized perioperative practices, and continuous research to enhance results and mitigate dangers. Full article
(This article belongs to the Section General Surgery)
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25 pages, 5547 KiB  
Article
Enhanced Aerosol Containment Performance of a Negative Pressure Hood with an Aerodynamic Cap Design: Multi-Method Validation Using CFD, PAO Particles, and Microbial Testing
by Seungcheol Ko, Kisub Sung, Min Jae Oh, Yoonjic Kim, Min Ji Kim, Jung Woo Lee, Yoo Seok Park, Yong Hyun Kim, Ju Young Hong and Joon Sang Lee
Bioengineering 2025, 12(6), 624; https://doi.org/10.3390/bioengineering12060624 - 9 Jun 2025
Viewed by 474
Abstract
Healthcare providers performing aerosol-generating procedures (AGPs) face significant infection risks, emphasizing the critical need for effective aerosol containment systems. In this study, we developed and validated a negative pressure chamber enhanced with an innovative aerodynamic cap structure designed to optimize aerosol containment. Initially, [...] Read more.
Healthcare providers performing aerosol-generating procedures (AGPs) face significant infection risks, emphasizing the critical need for effective aerosol containment systems. In this study, we developed and validated a negative pressure chamber enhanced with an innovative aerodynamic cap structure designed to optimize aerosol containment. Initially, computational fluid dynamics (CFD) simulations were performed to evaluate multiple structural improvement ideas, including air curtains, bidirectional suction, and aerodynamic cap structures. Among these, the aerodynamic cap was selected due to its superior predicted containment performance, practical feasibility, and cost-effectiveness. The CFD analyses employed realistic transient boundary conditions, precise turbulence modeling using the shear stress transport (SST) k–ω model, and detailed droplet evaporation dynamics under realistic humidity conditions. A full-scale prototype incorporating the selected aerodynamic cap was fabricated and evaluated using physical polyalphaolefin (PAO) particle leakage tests and biological aerosol validation with aerosolized Bacillus subtilis. For the physical leakage tests, the chamber opening was divided into nine sections, and the aerosol dispersion was tested in three distinct directions: ceiling-directed, toward the suction hole, and opposite the suction hole. These tests demonstrated significantly stabilized airflow and substantial reductions in aerosol leakage, consistently maintaining containment levels below the critical threshold of 0.3%, especially under transient coughing conditions. The biological aerosol experiments, conducted in a simulated emergency department environment, involved aerosolizing bacteria continuously for one hour. The results confirmed the effectiveness of the aerodynamic cap structure in achieving at least a one millionth (10−6) reduction in the aerosolized bacterial leakage compared to the control conditions. These findings highlight the importance and effectiveness of advanced CFD modeling methodologies in accurately predicting aerosol dispersion and improving containment strategies. Although further studies assessing the structural durability, long-term operational ease, and effectiveness against pathogenic microorganisms are required, the aerodynamic cap structure presents a promising, clinically practical infection control solution for widespread implementation during aerosol-generating medical procedures. Full article
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10 pages, 28452 KiB  
Article
Highly Linear 2.6 GHz Band InGaP/GaAs HBT Power Amplifier IC Using a Dynamic Predistorter
by Hyeongjin Jeon, Jaekyung Shin, Woojin Choi, Sooncheol Bae, Kyungdong Bae, Soohyun Bin, Sangyeop Kim, Yunhyung Ju, Minseok Ahn, Gyuhyeon Mun, Keum Cheol Hwang, Kang-Yoon Lee and Youngoo Yang
Electronics 2025, 14(11), 2300; https://doi.org/10.3390/electronics14112300 - 5 Jun 2025
Viewed by 416
Abstract
This paper presents a highly linear two-stage InGaP/GaAs power amplifier integrated circuit (PAIC) using a dynamic predistorter for 5G small-cell applications. The proposed predistorter, based on a diode-connected transistor, utilizes a supply voltage to accurately control the linearization characteristics by adjusting its dc [...] Read more.
This paper presents a highly linear two-stage InGaP/GaAs power amplifier integrated circuit (PAIC) using a dynamic predistorter for 5G small-cell applications. The proposed predistorter, based on a diode-connected transistor, utilizes a supply voltage to accurately control the linearization characteristics by adjusting its dc current. It is connected in parallel with an inter-stage of the two-stage PAIC through a series configuration of a resistor and an inductor, and features a shunt capacitor at the base of the transistor. These passive components have been optimized to enhance the linearization performance by managing the RF signal’s coupling to the diode. Using these optimized components, the AM−AM and AM−PM nonlinearities arising from the nonlinear resistance and capacitance in the diode can be effectively used to significantly flatten the AM−AM and AM−PM characteristics of the PAIC. The proposed predistorter was applied to the 2.6 GHz two-stage InGaP/GaAs HBT PAIC. The IC was tested using a 5 × 5 mm2 module package based on a four-layer laminate. The load network was implemented off-chip on the laminate. By employing a continuous-wave (CW) signal, the AM−AM and AM−PM characteristics at 2.55–2.65 GHz were improved by approximately 0.05 dB and 3°, respectively. When utilizing the new radio (NR) signal, based on OFDM cyclic prefix (CP) with a signal bandwidth of 100 MHz and a peak-to-average power ratio (PAPR) of 9.7 dB, the power-added efficiency (PAE) reached at least 11.8%, and the average output power was no less than 24 dBm, achieving an adjacent channel leakage power ratio (ACLR) of −40.0 dBc. Full article
(This article belongs to the Section Microwave and Wireless Communications)
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16 pages, 4079 KiB  
Article
Synthesis and Applications of Encapsulated Glycol-Stabilized Lyotropic Cholesteric Liquid Crystal Hydrogels
by Yan-Ting Lin, Chung-Yu Kuo, Yi Shen, Alexander V. Emelyanenko and Chun-Yen Liu
Gels 2025, 11(6), 388; https://doi.org/10.3390/gels11060388 - 25 May 2025
Viewed by 449
Abstract
The micro-phase segregation of two incompatible components on a nanometer scale results in a unique solvent-induced extended anisotropic arrangement. With the addition of a chiral dopant, lyotropic liquid crystals can be induced to adopt a helical structure, forming lyotropic cholesteric liquid crystals capable [...] Read more.
The micro-phase segregation of two incompatible components on a nanometer scale results in a unique solvent-induced extended anisotropic arrangement. With the addition of a chiral dopant, lyotropic liquid crystals can be induced to adopt a helical structure, forming lyotropic cholesteric liquid crystals capable of reflecting incident light. In this study, to prevent fluid leakage in lyotropic materials, we encapsulated a series of hydrogel-stabilized lyotropic liquid crystals, presenting tunable structural colors visible in all directions, mimicking the color-changing characteristics of living organisms. Hydrogel scaffolds with controllable swelling behaviors were engineered by incorporating crosslinking monomers. To ensure stable integration of lyotropic liquid crystals, high-boiling-point ethylene glycol was employed as a fluid during the fabrication process. This study extensively explores the relationship between tensile force, temperature, and pressure and the color changes in lyotropic liquid crystals (LC). The results indicate that lyotropic LC membranes, stabilized by ethylene glycol and PDMS encapsulation, exhibit long-term stability, rendering them suitable for applications in temperature and pressure sensing. This approach ensures the continuous presence and stability of lyotropic liquid crystals within the hydrogel matrix. Full article
(This article belongs to the Section Gel Applications)
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24 pages, 1264 KiB  
Review
Indoor Abnormal Behavior Detection for the Elderly: A Review
by Tianxiao Gu and Min Tang
Sensors 2025, 25(11), 3313; https://doi.org/10.3390/s25113313 - 24 May 2025
Viewed by 778
Abstract
Due to the increased age of the global population, the proportion of the elderly population continues to rise. The safety of the elderly living alone is becoming an increasingly prominent area of concern. They often miss timely treatment due to undetected falls or [...] Read more.
Due to the increased age of the global population, the proportion of the elderly population continues to rise. The safety of the elderly living alone is becoming an increasingly prominent area of concern. They often miss timely treatment due to undetected falls or illnesses, which pose risks to their lives. In order to address this challenge, the technology of indoor abnormal behavior detection has become a research hotspot. This paper systematically reviews detection methods based on sensors, video, infrared, WIFI, radar, depth, and multimodal fusion. It analyzes the technical principles, advantages, and limitations of various methods. This paper further explores the characteristics of relevant datasets and their applicable scenarios and summarizes the challenges facing current research, including multimodal data scarcity, risk of privacy leakage, insufficient adaptability of complex environments, and human adoption of wearable devices. Finally, this paper proposes future research directions, such as combining generative models, federated learning to protect privacy, multi-sensor fusion for robustness, and abnormal behavior detection on the Internet of Things environment. This paper aims to provide a systematic reference for academic research and practical application in the field of indoor abnormal behavior detection. Full article
(This article belongs to the Section Wearables)
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17 pages, 4951 KiB  
Article
A 3-D Defect Profile Inversion Method Based on the Continuity Correction Strategy
by Chenlin Wang, Jianhua Tang, Yicheng Duan, Senxiang Lu and Hao Wen
Machines 2025, 13(6), 446; https://doi.org/10.3390/machines13060446 - 23 May 2025
Viewed by 356
Abstract
Magnetic flux leakage (MFL) detection is widely used in the non-destructive testing of pipelines. Inversion is a key step in MFL detection, and iterative inversion based on an optimization algorithm is an effective method for constructing the 3-D profile of defects in pipelines. [...] Read more.
Magnetic flux leakage (MFL) detection is widely used in the non-destructive testing of pipelines. Inversion is a key step in MFL detection, and iterative inversion based on an optimization algorithm is an effective method for constructing the 3-D profile of defects in pipelines. However, conventional inversion algorithms suffer from weak convergence ability and are prone to local optima, which can lead to significant errors in the results. To improve the algorithm’s convergence and result accuracy, this paper proposes a “continuity correction” strategy based on geometric features of defects, which examines the relative depth value of each depth point and corrects the values of implausible points. On this basis, this paper combines the secretary bird optimization algorithm (SBOA) with the differential evolution strategy and the perturbation strategy to enhance the search capability. Through an accuracy experiment and a robustness experiment on an experimental platform, it is demonstrated that the method outperforms conventional algorithms in terms of accuracy and robustness against interference when constructing the 3-D profile of defects. Full article
(This article belongs to the Section Machines Testing and Maintenance)
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