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Keywords = modal shape characterization

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37 pages, 1761 KiB  
Review
Iron–Immune Crosstalk at the Maternal–Fetal Interface: Emerging Mechanisms in the Pathogenesis of Preeclampsia
by Jieyan Zhong, Ruhe Jiang, Nan Liu, Qingqing Cai, Qi Cao, Yan Du and Hongbo Zhao
Antioxidants 2025, 14(7), 890; https://doi.org/10.3390/antiox14070890 - 19 Jul 2025
Viewed by 361
Abstract
Preeclampsia (PE) is a pregnancy-specific hypertensive disorder characterized by systemic inflammation, endothelial dysfunction, and placental insufficiency. While inadequate trophoblast invasion and impaired spiral artery remodeling have long been recognized as central to its pathogenesis, emerging evidence underscores the critical roles of dysregulated iron [...] Read more.
Preeclampsia (PE) is a pregnancy-specific hypertensive disorder characterized by systemic inflammation, endothelial dysfunction, and placental insufficiency. While inadequate trophoblast invasion and impaired spiral artery remodeling have long been recognized as central to its pathogenesis, emerging evidence underscores the critical roles of dysregulated iron metabolism and its crosstalk with immune responses, particularly macrophage-mediated inflammation, in driving PE development. This review systematically explores the dynamic changes in iron metabolism during pregnancy, including increased maternal iron demand, placental iron transport mechanisms, and the molecular regulation of placental iron homeostasis. We further explore the contribution of ferroptosis, an iron-dependent form of regulated cell death driven by lipid peroxidation, to trophoblast dysfunction and pregnancy-related diseases, including PE. Macrophages, pivotal immune regulators at the maternal–fetal interface, exhibit distinct polarization states that shape tissue remodeling and immune tolerance. We outline their origin, distribution, and polarization in pregnancy, and emphasize their aberrant phenotype and function in PE. The bidirectional crosstalk between iron and macrophages is also dissected: iron shapes macrophage polarization and function, while macrophages reciprocally modulate iron homeostasis. Notably, excessive reactive oxygen species (ROS) and pro-inflammatory cytokines secreted by M1-polarized macrophages may exacerbate trophoblast ferroptosis, amplifying placental injury. Within the context of PE, we delineate how iron overload and macrophage dysfunction synergize to potentiate placental inflammation and oxidative stress. Key iron-responsive immune pathways, such as the HO-1/hepcidin axis and IL-6/TNF-α signaling, are discussed in relation to disease severity. Finally, we highlight promising therapeutic strategies targeting the iron–immune axis, encompassing three key modalities—iron chelation therapy, precision immunomodulation, and metabolic reprogramming interventions—which may offer novel avenues for PE prevention and treatment. Full article
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23 pages, 2425 KiB  
Systematic Review
Emerging Image-Guided Navigation Techniques for Cardiovascular Interventions: A Scoping Review
by Majid Roshanfar, Mohammadhossein Salimi, Sun-Joo Jang, Albert J. Sinusas, Jiwon Kim and Bobak Mosadegh
Bioengineering 2025, 12(5), 488; https://doi.org/10.3390/bioengineering12050488 - 2 May 2025
Viewed by 813
Abstract
Background: Image-guided navigation has revolutionized precision cardiac interventions, yet current technologies face critical limitations in real-time guidance and procedural accuracy. Method: Here, we comprehensively evaluate state-of-the-art imaging modalities, from conventional fluoroscopy to emerging hybrid systems, analyzing their applications across coronary, structural, and electrophysiological [...] Read more.
Background: Image-guided navigation has revolutionized precision cardiac interventions, yet current technologies face critical limitations in real-time guidance and procedural accuracy. Method: Here, we comprehensively evaluate state-of-the-art imaging modalities, from conventional fluoroscopy to emerging hybrid systems, analyzing their applications across coronary, structural, and electrophysiological interventions. Results: We demonstrate that novel approaches combining optical coherence tomography with near-infrared spectroscopy or fluorescence achieve unprecedented plaque characterization and procedural guidance through simultaneous structural and molecular imaging. Our analysis reveals key challenges, including imaging artifacts and resolution constraints, while highlighting recent technological solutions incorporating artificial intelligence and robotics. We show that non-imaging alternatives, such as fiber optic real-shape sensing and electromagnetic tracking, complement traditional techniques by providing real-time navigation without radiation exposure. This paper also discusses the integration of image-guided navigation techniques into augmented reality systems and patient-specific modeling, highlighting initial clinical studies that demonstrate their significant promise in reducing procedural times and improving accuracy. These findings establish a framework for next-generation cardiac interventions, emphasizing the critical role of multimodal imaging platforms enhanced by AI-driven decision support. Conclusions: We conclude that continued innovation in hybrid imaging systems, coupled with advances in automation, will be essential for optimizing procedural outcomes and expanding access to complex cardiac interventions. Full article
(This article belongs to the Special Issue Advancements in Medical Imaging Technology)
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19 pages, 19634 KiB  
Article
Research on Forced Vibration Model of End Effector Under Low-Frequency Excitation and Vibration-Suppression Technology
by Changqi Li, Henan Song, Ruirui Li, Jianwei Wu, Xiaobiao Shan and Jiubin Tan
Micromachines 2025, 16(2), 131; https://doi.org/10.3390/mi16020131 - 23 Jan 2025
Viewed by 867
Abstract
The positioning accuracy of the end effector is the core index that affects the robot’s performance. However, to achieve lightweight and functional requirements, the construction of end effectors is becoming more complex. Lightweight design through slotting is becoming more common. This leads to [...] Read more.
The positioning accuracy of the end effector is the core index that affects the robot’s performance. However, to achieve lightweight and functional requirements, the construction of end effectors is becoming more complex. Lightweight design through slotting is becoming more common. This leads to the fact that the traditional mathematical model cannot accurately characterize the vibration of the end effector. This study proposed the multi-stepwise beam model. It employed the separation of variables and element transmitting method to obtain the mathematical model of the modal shape functions and the natural frequencies. Meanwhile, the vibration response of the end effector under fixed-end excitation was analyzed, and the conclusions were made through experimental research. The direct inverse controller was presented to achieve vibration suppression. The experimental results indicate that the amplitude suppression rate reaches 50%. The system’s equations of motion were solved numerically to analyze the exact relationships for the response and excitation of the beam considered. Full article
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20 pages, 18408 KiB  
Article
Vibration-Based Damage Prediction in Composite Concrete–Steel Structures Using Finite Elements
by Mario D. Cedeño-Rodríguez, Sergio J. Yanez, Erick I. Saavedra-Flores, Carlos Felipe Guzmán and Juan Carlos Pina
Buildings 2025, 15(2), 200; https://doi.org/10.3390/buildings15020200 - 10 Jan 2025
Cited by 1 | Viewed by 1156
Abstract
The prediction of structural damage through vibrational analysis is a critical task in the field of composite structures. Structural defects and damage can negatively influence the load-carrying capacity of the beam. Therefore, detecting structural damage early is essential to preventing catastrophic failures. This [...] Read more.
The prediction of structural damage through vibrational analysis is a critical task in the field of composite structures. Structural defects and damage can negatively influence the load-carrying capacity of the beam. Therefore, detecting structural damage early is essential to preventing catastrophic failures. This study addresses the challenge of predicting damage in composite concrete–steel beams using a vibration-based finite element approach. To tackle this complex task, a finite element model to a quasi-static analysis emulating a four-point pure bending experimental test was performed. Notably, the numerical model equations were carefully modified using the Newton–Raphson method to account for the stiffness degradation resulting from material strains. These modified equations were subsequently employed in a modal analysis to compute modal shapes and natural frequencies corresponding to the stressed state. The difference between initial and damaged modal shape curvatures served as the foundation for predicting a damage index. The approach effectively captured stiffness degradation in the model, leading to observable changes in modal responses, including a reduction in natural frequencies and variations in modal shapes. This enabled the accurate prediction of damage instances during construction, service, or accidental load scenarios, thereby enhancing the structural and operational safety of composite system designs. This research contributes to the advancement of vibration-based methods for damage detection, emphasizing the complexities in characterizing damage in composite structural geometries. Further exploration and refinement of this approach are essential for the precise classification of damage types. Full article
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14 pages, 4492 KiB  
Article
Conjugated Human Serum Albumin/Gold-Silica Nanoparticles as Multifunctional Carrier of a Chemotherapeutic Drug
by Elena Morrone, Lucie Sancey, Fabien Dalonneau, Loredana Ricciardi and Massimo La Deda
Int. J. Mol. Sci. 2024, 25(24), 13701; https://doi.org/10.3390/ijms252413701 - 21 Dec 2024
Cited by 1 | Viewed by 1318
Abstract
We report the design and development of a novel multifunctional nanostructure, RB-AuSiO2_HSA-DOX, where tri-modal cancer treatment strategies—photothermal therapy (PTT), photodynamic therapy (PDT), chemotherapy—luminescent properties and targeting are integrated into the same scaffold. It consists of a gold core with optical and [...] Read more.
We report the design and development of a novel multifunctional nanostructure, RB-AuSiO2_HSA-DOX, where tri-modal cancer treatment strategies—photothermal therapy (PTT), photodynamic therapy (PDT), chemotherapy—luminescent properties and targeting are integrated into the same scaffold. It consists of a gold core with optical and thermo-plasmonic properties and is covered by a silica shell entrapping a well-known photosensitizer and luminophore, Rose Bengal (RB). The nanoparticle surface was decorated with Human Serum Albumin (HSA) through a covalent conjugation to confer its targeting abilities and as a carrier of Doxorubicin (DOX), one of the most effective anticancer drugs in clinical chemotherapy. The obtained nanostructure was fully characterized through transmission electron microscopy (TEM), dynamic light scattering (DLS) and UV-visible spectroscopy, with a homogeneous and spherical shape, an average diameter of about 60 nm and negative ζ-potential value Singlet oxygen generation and photothermal properties were explored under green light irradiation. The interaction between DOX-HSA anchored on the nanoplatform was investigated by fluorescence spectroscopy and compared to that of DOX-HSA, pointing out different accessibility of the drug molecules to the HSA binding sites, whether the protein is free or bound to the nanoparticle surface. To the best of our knowledge, there are no studies comparing a drug–HSA interaction with that of the same protein anchored to nanoparticles. Furthermore, the uptake of RB-AuSiO2_HSA-DOX into MDA-MB-231 mammary cells was assessed by confocal imaging, highlighting—at early time of incubation and as demonstrated by the increased DOX luminescence displayed within cells—a better internalization of the carried anticancer drug compared to the free one, making the obtained nanostructure a suitable and promising platform for an anticancer multimodal approach. Full article
(This article belongs to the Special Issue External Stimuli-Responsive Nanomaterials for Diagnosis and Treatment)
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15 pages, 11143 KiB  
Article
Toxicological Assessment of 2-Hydroxychalcone-Mediated Photodynamic Therapy: Comparative In Vitro and In Vivo Approaches
by Níura Madalena Bila, Carolina Orlando Vaso, Jenyffie Araújo Belizário, Letícia Ribeiro Assis, Luís Octávio Regasini, Carla Raquel Fontana, Ana Marisa Fusco-Almeida, Caroline Barcelos Costa-Orlandi and Maria José Soares Mendes-Giannini
Pharmaceutics 2024, 16(12), 1523; https://doi.org/10.3390/pharmaceutics16121523 - 26 Nov 2024
Viewed by 989
Abstract
Background: Photodynamic therapy (PDT) is a treatment modality that uses light to activate a photosensitizing agent, destroying target cells. The growing awareness of the necessity to reduce or eliminate the use of mammals in research has prompted the search for safer toxicity testing [...] Read more.
Background: Photodynamic therapy (PDT) is a treatment modality that uses light to activate a photosensitizing agent, destroying target cells. The growing awareness of the necessity to reduce or eliminate the use of mammals in research has prompted the search for safer toxicity testing models aligned with the new global guidelines and compliant with the relevant regulations. Objective: The objective of this study was to assess the impact of PDT on alternative models to mammals, including in vitro three-dimensional (3D) cultures and in vivo, in invertebrate animals, utilizing a potent photosensitizer, 2-hydroxychalcone. Methods: Cytotoxicity was assessed in two cellular models: monolayer (2D) and 3D. For this purpose, spheroids of two cell lines, primary dermal fibroblasts (HDFa) and adult human epidermal cell keratinocytes (HaCat), were developed and characterized following criteria on cell viability, shape, diameter, and number of cells. The survival percentages of Caenorhabditis elegans and Galleria mellonella were evaluated at 1 and 7 days, respectively. Results: The findings indicated that all the assessed platforms are appropriate for investigating PDT toxicity. Furthermore, 2-hydroxychalcone demonstrated low toxicity in the absence of light and when mediated by PDT across a range of in vitro (2D and 3D cultures) and in vivo (invertebrate animal models, including G. mellonella and C. elegans) models. Conclusion: There was a strong correlation between the in vitro and in vivo tests, with similar toxicity results, particularly in the 3D models and C. elegans, where the concentration for 50% viability was approximately 100 µg/mL. Full article
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16 pages, 4183 KiB  
Article
MEMS-Based Vibration Acquisition for Modal Parameter Identification of Substation Frame
by Ruochen Qiang, Ming Sheng, Dongxu Su, Yachen Wang, Xianghong Liu and Qing Sun
Appl. Sci. 2024, 14(18), 8190; https://doi.org/10.3390/app14188190 - 12 Sep 2024
Cited by 1 | Viewed by 3797
Abstract
As a critical component of substations, the substation frames are characterized by significant height and span, which presents substantial challenges and risks in conducting dynamic response tests using traditional sensors. To simplify these difficulties, this paper introduces an experimental method utilizing MEMS sensor-based [...] Read more.
As a critical component of substations, the substation frames are characterized by significant height and span, which presents substantial challenges and risks in conducting dynamic response tests using traditional sensors. To simplify these difficulties, this paper introduces an experimental method utilizing MEMS sensor-based vibration acquisition. In this approach, smartphones equipped with MEMS sensors are deployed on the target structure to collect vibration data under environmental excitation. This method was applied in a dynamic field test of a novel composite substation frame. During the test, the proposed MEMS-based vibration acquisition method was conducted in parallel with traditional ultra-low-frequency vibration acquisition methods to validate the accuracy of the MEMS data. The results demonstrated that the MEMS sensors not only simplified the testing process but also provided reliable data, offering greater advantages in testing convenience compared with traditional contact methods. The modal parameters of the substation frame, including modal frequencies, damping ratios, and mode shapes, were subsequently identified using the covariance-driven stochastic subspace identification method. The experimental methodology and findings presented in this paper offer valuable insights for structural dynamic response testing and the wind-resistant design of substation frames. Full article
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8 pages, 1673 KiB  
Case Report
Anterior Segment Optical Coherence Tomography for the Tailored Treatment of Mooren’s Ulcer: A Case Report
by Luca Lucchino, Elvia Mastrogiuseppe, Francesca Giovannetti, Alice Bruscolini, Marco Marenco and Alessandro Lambiase
J. Clin. Med. 2024, 13(18), 5384; https://doi.org/10.3390/jcm13185384 - 11 Sep 2024
Cited by 1 | Viewed by 1491
Abstract
Background: Mooren’s ulcer (MU) is a rare and debilitating form of peripheral ulcerative keratitis (PUK), characterized by a crescent-shaped ulcer with a distinctive overhanging edge at the corneal periphery. If left untreated, MU can lead to severe complications such as corneal perforation and [...] Read more.
Background: Mooren’s ulcer (MU) is a rare and debilitating form of peripheral ulcerative keratitis (PUK), characterized by a crescent-shaped ulcer with a distinctive overhanging edge at the corneal periphery. If left untreated, MU can lead to severe complications such as corneal perforation and blindness. Despite various treatment approaches, including anti-inflammatory and cytotoxic drugs, as well as surgical interventions, there is no clear evidence of the most effective treatment due to the lack of randomized controlled trials. AS-OCT is a non-invasive imaging technique that provides high-resolution cross-sectional images of the anterior segment, allowing for accurate evaluation of corneal ulcer characteristics, including depth, extent, and disease progression. Methods: We present the case of a 20-year-old male patient with MU managed using a stepladder approach, which included local and systemic corticosteroids, limbal conjunctival resection, and Cyclosporine A 1% eye drops. The patient underwent consecutive AS-OCT examinations and strict follow-up to tailor systemic and topical therapy. Results: Complete healing of the corneal ulcer with resolution of the inflammatory process was achieved. There was no recurrence of the disease at the 7-month follow-up. AS-OCT demonstrated progressive reorganization and thickening of the stromal tissue until the complete recovery of stromal thickness. Conclusions: The AS-OCT imaging modality allowed for the accurate evaluation of corneal ulcer characteristics, facilitating informed decision-making regarding the use of systemic immunosuppression, surgical interventions, and local immunomodulation and providing detailed and precise assessment of disease progression. This approach enabled a tailored and effective treatment strategy for the patient and played a critical role in guiding the therapeutic approach. Full article
(This article belongs to the Special Issue Clinical Utility of Optical Coherence Tomography in Ophthalmology)
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26 pages, 12522 KiB  
Article
A Vision–Language Model-Based Traffic Sign Detection Method for High-Resolution Drone Images: A Case Study in Guyuan, China
by Jianqun Yao, Jinming Li, Yuxuan Li, Mingzhu Zhang, Chen Zuo, Shi Dong and Zhe Dai
Sensors 2024, 24(17), 5800; https://doi.org/10.3390/s24175800 - 6 Sep 2024
Cited by 4 | Viewed by 2149
Abstract
As a fundamental element of the transportation system, traffic signs are widely used to guide traffic behaviors. In recent years, drones have emerged as an important tool for monitoring the conditions of traffic signs. However, the existing image processing technique is heavily reliant [...] Read more.
As a fundamental element of the transportation system, traffic signs are widely used to guide traffic behaviors. In recent years, drones have emerged as an important tool for monitoring the conditions of traffic signs. However, the existing image processing technique is heavily reliant on image annotations. It is time consuming to build a high-quality dataset with diverse training images and human annotations. In this paper, we introduce the utilization of Vision–language Models (VLMs) in the traffic sign detection task. Without the need for discrete image labels, the rapid deployment is fulfilled by the multi-modal learning and large-scale pretrained networks. First, we compile a keyword dictionary to explain traffic signs. The Chinese national standard is used to suggest the shape and color information. Our program conducts Bootstrapping Language-image Pretraining v2 (BLIPv2) to translate representative images into text descriptions. Second, a Contrastive Language-image Pretraining (CLIP) framework is applied to characterize not only drone images but also text descriptions. Our method utilizes the pretrained encoder network to create visual features and word embeddings. Third, the category of each traffic sign is predicted according to the similarity between drone images and keywords. Cosine distance and softmax function are performed to calculate the class probability distribution. To evaluate the performance, we apply the proposed method in a practical application. The drone images captured from Guyuan, China, are employed to record the conditions of traffic signs. Further experiments include two widely used public datasets. The calculation results indicate that our vision–language model-based method has an acceptable prediction accuracy and low training cost. Full article
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21 pages, 7190 KiB  
Article
Experimental and Simulation Studies on the Mn Oxidation State Evolution of a Li2O-MnOx-CaO-SiO2 Slag Analogue
by Sven Hampel, Iyad Alabd Alhafez, Alena Schnickmann, Sophie Wunderlich, Haojie Li, Michael Fischlschweiger, Thomas Schirmer, Nina Merkert and Ursula E. A. Fittschen
Minerals 2024, 14(9), 868; https://doi.org/10.3390/min14090868 - 26 Aug 2024
Cited by 2 | Viewed by 1367
Abstract
This manuscript presents the results from the synthesis and characterization of a slag analogue with a nominal composition of 17 wt% LiMnO2 and 83 wt% Ca2SiO4 encountering fairly high cooling rates in order to study the evolution of Mn-species. [...] Read more.
This manuscript presents the results from the synthesis and characterization of a slag analogue with a nominal composition of 17 wt% LiMnO2 and 83 wt% Ca2SiO4 encountering fairly high cooling rates in order to study the evolution of Mn-species. The Mn species was also simulated from 1223 K to 1773 K using a thermodynamic model, assuming a homogeneous melt. The micro-composition including the Mn species of the solidified slag was determined experimentally, and was used as basis for molecular dynamics (MD) simulation. The MD simulation provides information on structure and viscosity at high temperatures, which are otherwise difficult to access. These parameters significantly influence oxidation state of redox-active elements and the solidified product. The micro-composition analyzed by electron probe micro analysis (EPMA) and synchrotron-based micro-X-ray fluorescence (micro-XRF) showed that Mn-rich and Ca-Si-rich phases are separated. While the Mn-O phases did not contain noticeable Ca, the Ca2SiO4 phase had incorporated 0.6 wt% of Mn. The slag solidified into round-shaped and droplet-shaped grains of a Li-Mn-oxide, some Mn3O4 and Ca2SiO4. The powder X-ray diffraction (PXRD) confirmed the formation of larnite; the identity of the Li-Mn-oxide, however, remained inconclusive. The Mn oxidation state (OS) was identified using synchrotron-based micro-X-ray absorption near edge spectroscopy (micro-XANES). The Mn-O grains matched well with Li-Mn-oxides and a Mn OS: +3, e.g., LiMn3+O2. Small areas matching hausmannite (Mn2+Mn23+O4) were also identified. The OS of Mn in the silicate phase could not be identified. For comparison, a slowly cooled slag analogue with similar composition, but higher Si content, was also subjected to micro-XANES. The slowly cooled slag formed long Mn-rich needles in a matrix of large calcium silicate crystals. The Mn-rich crystals matched well with the XANES spectrum of a Mn3+ Li-oxide like LiMn3+O2. At the rim of the needles, the Mn-spectra matched well the hausmannite (Mn2+Mn23+O4) reference. In the silicate phases, Mn had an OS: +2, unambiguously. The melt structure at different temperatures of two compositions, i.e., LiMn3+O2 and Ca2SiO4, was simulated using molecular dynamics (MD). They serve as model compositions, assuming a heterogeneous melt. The results show significant different degrees of polymerization and viscosity. Information from MD simulations can support the identification of potentially different oxygen permeability and with that prediction of oxidation states. The bulk composition was identified by inductively coupled plasma optical emission spectrometry (ICP-OES), bulk structure by PXRD and bulk species by lab-XANES. The synchrotron micro analysis including micro-XRD were performed at the microfocus beamline I18 at the Diamond Light Source. Pure reference compounds were prepared and characterized with the same multi-modal approach. Full article
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15 pages, 2061 KiB  
Article
Transfer Learning-Based Approach for Thickness Estimation on Optical Coherence Tomography of Varicose Veins
by Maryam Viqar, Violeta Madjarova, Elena Stoykova, Dimitar Nikolov, Ekram Khan and Keehoon Hong
Micromachines 2024, 15(7), 902; https://doi.org/10.3390/mi15070902 - 10 Jul 2024
Viewed by 1109
Abstract
In-depth mechanical characterization of veins is required for promising innovations of venous substitutes and for better understanding of venous diseases. Two important physical parameters of veins are shape and thickness, which are quite challenging in soft tissues. Here, we propose the method TREE [...] Read more.
In-depth mechanical characterization of veins is required for promising innovations of venous substitutes and for better understanding of venous diseases. Two important physical parameters of veins are shape and thickness, which are quite challenging in soft tissues. Here, we propose the method TREE (TransfeR learning-based approach for thicknEss Estimation) to predict both the segmentation map and thickness value of the veins. This model incorporates one encoder and two decoders which are trained in a special manner to facilitate transfer learning. First, an encoder–decoder pair is trained to predict segmentation maps, then this pre-trained encoder with frozen weights is paired with a second decoder that is specifically trained to predict thickness maps. This leverages the global information gained from the segmentation model to facilitate the precise learning of the thickness model. Additionally, to improve the performance we introduce a sensitive pattern detector (SPD) module which further guides the network by extracting semantic details. The swept-source optical coherence tomography (SS-OCT) is the imaging modality for saphenous varicose vein extracted from the diseased patients. To demonstrate the performance of the model, we calculated the segmentation accuracy—0.993, mean square error in thickness (pixels) estimation—2.409 and both these metrics stand out when compared with the state-of-art methods. Full article
(This article belongs to the Special Issue Optical Tools for Biomedical Applications)
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20 pages, 6045 KiB  
Article
Static and Dynamic Response Analysis of Flexible Photovoltaic Mounts
by Yibing Lou, Jian Zhang and Yuxin Pan
Buildings 2024, 14(7), 2037; https://doi.org/10.3390/buildings14072037 - 4 Jul 2024
Cited by 5 | Viewed by 1635
Abstract
Traditional rigid photovoltaic (PV) support structures exhibit several limitations during operational deployment. Therefore, flexible PV mounting systems have been developed. These flexible PV supports, characterized by their heightened sensitivity to wind loading, necessitate a thorough analysis of their static and dynamic responses. This [...] Read more.
Traditional rigid photovoltaic (PV) support structures exhibit several limitations during operational deployment. Therefore, flexible PV mounting systems have been developed. These flexible PV supports, characterized by their heightened sensitivity to wind loading, necessitate a thorough analysis of their static and dynamic responses. This study involves the development of a MATLAB code to simulate the fluctuating wind load time series and the subsequent structural modeling in SAP2000 to evaluate the safety performance of flexible PV supports under extreme wind conditions. The research explores the critical wind speeds relative to varying spans and prestress levels within the system. Modal analysis reveals that the flexible PV support structures do not experience resonant frequencies that could amplify oscillations. The analysis also provides insights into the mode shapes of these structures. An analysis of the wind-induced vibration responses of the flexible PV support structures was conducted. The results indicated that the mid-span displacements and the axial forces in the wind-resistant cables are greater under wind-pressure conditions compared to wind-suction conditions. Conversely, for mid-span accelerations, the wind-suction conditions resulted in higher values than the wind-pressure conditions. Furthermore, the wind-induced vibration coefficients were computed, with findings suggesting a recommended coefficient range of 1.5 to 2.52. To mitigate wind-induced vibrations, structural reinforcement strategies were assessed. The results indicate that the introduction of support beams at the mid-span is the most effective measure to attenuate wind-induced vibrational responses. Conversely, increasing the diameter of the tensioned cables exhibited a negligible effect in reducing these responses. On the other hand, implementing stabilizing cables at the mid-span demonstrated a substantial reduction in wind-induced vibrational responses under suction wind-load conditions. Full article
(This article belongs to the Special Issue Advances in Research on Structural Dynamics and Health Monitoring)
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11 pages, 6862 KiB  
Communication
Ultrasonography and Postmortem Magnetic Resonance Imaging of Bilateral Ocular Disease in a Heifer
by Takeshi Tsuka, Yuji Sunden, Takehito Morita, Md Shafiqul Islam and Osamu Yamato
Ruminants 2024, 4(1), 125-135; https://doi.org/10.3390/ruminants4010008 - 8 Mar 2024
Viewed by 1806
Abstract
Bovine ocular diseases are typically characterized by the concurrent appearances of both macroscopic and intraocular abnormalities. This study examines the diagnostic efficacy of a combination of ultrasonography and magnetic resonance imaging (MRI) for the bilateral ocular disease observed in a 9-month-old Japanese Black [...] Read more.
Bovine ocular diseases are typically characterized by the concurrent appearances of both macroscopic and intraocular abnormalities. This study examines the diagnostic efficacy of a combination of ultrasonography and magnetic resonance imaging (MRI) for the bilateral ocular disease observed in a 9-month-old Japanese Black heifer. This case presented with bilateral strabismus and a white-colored lens structure in the right eye. A combination of ultrasonography and MRI revealed formations of corn-like and V-shaped membranous structures within the vitreous cavities of the left and right eyeballs, respectively. In the right eye, a cataract was suspected on both ultrasonogram and MRI. This case involved bilateral retinal detachments and strabismus similar to the signs of an autosomal recessive hereditary ocular disease; however, the cataract in the right eye differed from that hereditary disease. Finally, in genetic analysis, a known mutation of the WFDC1 gene was not detected. Ultrasonography is superior to MRI in demonstrating intraocular pathological changes. On the other hand, MRI is helpful for evaluating invasiveness of the ocular lesions to the peripheral structures. Thus, the combined use of these imaging modalities is recommended for diagnosing various bovine ocular diseases. Full article
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19 pages, 2047 KiB  
Article
Investigating the Influence of the Improved Multibody Rope Approach on the Structural Behavior of Dakar Mosque Gridshell Structure
by Jonathan Melchiorre, Stefano Invernizzi and Amedeo Manuello Bertetto
Buildings 2024, 14(3), 598; https://doi.org/10.3390/buildings14030598 - 23 Feb 2024
Cited by 1 | Viewed by 1128
Abstract
Gridshell structures are characterized by an impressive strength-to-weight ratio, allowing their application in large-span roofing structures. However, their complex construction process and maintenance limited their widespread application. In recent years, the development of parametric and computational design tools has rekindled interest in this [...] Read more.
Gridshell structures are characterized by an impressive strength-to-weight ratio, allowing their application in large-span roofing structures. However, their complex construction process and maintenance limited their widespread application. In recent years, the development of parametric and computational design tools has rekindled interest in this type of structure. Among these techniques, the Multibody Rope Approach (MRA) is a form-finding method based on the dynamic equilibrium of a system of masses (nodes) connected by ropes, which allows optimizing the structural shape starting from the dual geometry of the funicular network. To optimize the construction process, an improved version of the MRA, i-MRA, has been recently developed by the authors with the goal of uniforming the size of the structural components. To investigate the impact of the i-MRA method on the structural behavior of gridshell structures, the practical case of the design of a mosque roof is here analyzed. The comparison is carried out in terms of structural performance with respect to permanent and equivalent quasi-static loads. In addition, free-vibration natural-frequency shift is obtained by performing linear modal analysis. Finally, the global behavior with respect to buckling and elastic instability is assessed solving the relevant eigenvalue problem. The results demonstrate that for the roofing of the Dakar mosque, the structural configuration obtained through i-MRA is superior in terms of both construction efficiency and structural performance. The achieved shape exhibits a more uniform distribution of stresses induced by the applied loads together with very limited structural element typologies. Full article
(This article belongs to the Section Building Structures)
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17 pages, 2190 KiB  
Article
The Effectiveness of an Adaptive Method to Analyse the Transition between Tumour and Peritumour for Answering Two Clinical Questions in Cancer Imaging
by Margherita Mottola, Rita Golfieri and Alessandro Bevilacqua
Sensors 2024, 24(4), 1156; https://doi.org/10.3390/s24041156 - 9 Feb 2024
Cited by 1 | Viewed by 1383
Abstract
Based on the well-known role of peritumour characterization in cancer imaging to improve the early diagnosis and timeliness of clinical decisions, this study innovated a state-of-the-art approach for peritumour analysis, mainly relying on extending tumour segmentation by a predefined fixed size. We present [...] Read more.
Based on the well-known role of peritumour characterization in cancer imaging to improve the early diagnosis and timeliness of clinical decisions, this study innovated a state-of-the-art approach for peritumour analysis, mainly relying on extending tumour segmentation by a predefined fixed size. We present a novel, adaptive method to investigate the zone of transition, bestriding tumour and peritumour, thought of as an annular-like shaped area, and detected by analysing gradient variations along tumour edges. For method validation, we applied it on two datasets (hepatocellular carcinoma and locally advanced rectal cancer) imaged by different modalities and exploited the zone of transition regions as well as the peritumour ones derived by adopting the literature approach for building predictive models. To measure the zone of transition’s benefits, we compared the predictivity of models relying on both “standard” and novel peritumour regions. The main comparison metrics were informedness, specificity and sensitivity. As regards hepatocellular carcinoma, having circular and regular shape, all models showed similar performance (informedness = 0.69, sensitivity = 84%, specificity = 85%). As regards locally advanced rectal cancer, with jagged contours, the zone of transition led to the best informedness of 0.68 (sensitivity = 89%, specificity = 79%). The zone of transition advantages include detecting the peritumour adaptively, even when not visually noticeable, and minimizing the risk (higher in the literature approach) of including adjacent diverse structures, which was clearly highlighted during image gradient analysis. Full article
(This article belongs to the Special Issue Feature Papers in "Sensing and Imaging" Section 2023)
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