Search Results (301)

Cardiovascular disease encompasses a wide group of conditions that affect the heart and blood vessels. Of these diseases, cardiomyopathies and arrhythmias specifically have been well-studied in their relationship to cardiac dyads, nanoscopic structures that connect electrical signals to muscle contraction. The proper development and positioning of dyads is essential in excitation–contraction (EC) coupling and, thus, beating of the heart. Three proteins, namely CMYA5, JPH2, and BIN1, are responsible for maintaining the dyadic cleft between the T-tubule and junctional sarcoplasmic reticulum (jSR). Various other dyadic proteins play integral roles in the primary function of the dyad—translating a propagating action potential (AP) into a myocardial contraction. Ca²⁺, a secondary messenger in this process, acts as an allosteric activator of the sarcomere, and its cytoplasmic concentration is regulated by the dyad. Loss-of-function mutations have been shown to result in cardiomyopathies and arrhythmias. Adeno-associated virus (AAV) gene therapy with dyad components can rescue dyadic dysfunction, which results in cardiomyopathies and arrhythmias. Overall, the dyad and its components serve as essential mediators of calcium homeostasis and excitation–contraction coupling in the mammalian heart and, when dysfunctional, result in significant cardiac dysfunction, arrhythmias, morbidity, and mortality. Full article

It was unknown whether hyperthermia increased the efficacy of histamine to raise the force of cardiac contractions via human H1-histamine receptors. To that end, we measured the force in isolated human atrial preparations (HAPs) excised from the right atrium of patients who underwent cardiac surgery due to severe two- or three-vessel coronary heart disease. For comparison, we also measured the force in paced (1 Hz) left and spontaneously beating right atrial preparations of transgenic mice overexpressing cardiac human H1-histamine receptors (H1-TG). Histamine (100 µM) was less efficient in raising the force in left atrial preparations from H1 TG mouse atria under hyperthermia than under hypothermia. Oppositely, histamine was more efficient in augmenting force during hyperthermia than during hypothermia in isolated electrically stimulated (1 Hz) HAPs. In sum, the contractile response to activation of H1-histamine receptor in H1-TG mice and in HAPs are opposite with regard to hyperthermia dependence. In patients with fever, histamine might thus be important, to preserve cardiac contractile function as a compensatory mechanism. Full article

The possibility of collecting new archaeological elements useful in reconstructing the dynamics of population, production and commercial activities in the Bronze Age at the edge of the central-southern Venice Lagoon was provided between 2023 and 2024 thanks to an intervention of rescue archaeology planned during some water restoration works in the Giare–Mira area. Three small excavations revealed, approximately one meter below the current surface and covered by alluvial sediments, a rather complex palimpsest dated to the late Recent and the early Final Bronze Age. Three large circular pits containing exclusively purified grey/blue clay and very rare inclusions of vegetable fibres, and many large, fired clay vessels’ bases, walls and rims clustered in concentrated assemblages and random deposits point to potential on-site production. Two pyro-technological structures, one characterised by a sub-circular combustion chamber and a long inlet channel/praefurnium, and the second one with a sub-rectangular shape with arched niches along its southern side, complete the exceptional context here discovered. To analyse the relationship between the site and the natural sedimentary succession and to evaluate the possible extension of this site, three electrical resistivity tomography (ERT) and low-frequency electromagnetic (FDEM) measurements were collected. Several manual core drillings associated with remote sensing integrated the geophysical data in the analysis of the geomorphological evolution of this area, clearly related to different phases of fluvial activity, in a framework of continuous relative sea level rise. The typology and chronology of the archaeological structures and materials, currently undergoing further analyses, support the interpretation of the site as a late Recent/early Final Bronze Age productive site. Geophysical and geomorphological data provide information on the palaeoenvironmental setting, suggesting that the site was located on a fine-grained, stable alluvial plain at a distance of a few kilometres from the lagoon shore to the south-east and the course of the Brenta River to the north. The archaeological site was buried by fine-grained floodplain deposits attributed to the Brenta River. The good preservation of the archaeological structures buried by fluvial sediments suggests that the site was abandoned soon before sedimentation started. Full article

Both biosystems and engineering fields demand advanced friction-reducing and lubricating materials. Due to their hydrophilicity and tissue-mimicking properties, hydrogels are ideal candidates for use as lubricants in water-based environments. They are particularly well-suited for applications involving biocompatibility or interactions with intelligent devices such as soft robots. However, external environments, whether within the human body or in engineering applications, often present a wide range of dynamic conditions, including variations in shear stress, temperature, light, pH, and electric fields. Additionally, hydrogels inherently possess low mechanical strength, and their dimensional stability can be compromised by changes during hydration. This review focuses on recent advancements in using environmentally responsive hydrogels as lubricants. It explores strategies involving physical or structural modifications, as well as the incorporation of smart chemical functional groups into hydrogel polymer chains, which enable diverse responsive mechanisms. Drawing on both the existing literature and our own research, we also examine how composite friction materials where hydrogels serve as water-based lubricants offer promising solutions for demanding engineering environments, such as bearing systems in marine vessels. Full article

Hybrid-energy vessels offer significant advantages in reducing carbon emissions and air pollutants by integrating traditional internal combustion engines, electric motors, and new energy technologies. However, during operation, the high reliance of hybrid-energy ships on networks and communication systems poses serious data security risks. Meanwhile, the complexity of energy scheduling presents challenges in obtaining feasible solutions. To address these issues, this paper proposes an innovative two-stage security optimization scheduling framework aimed at simultaneously improving the security and economy of the system. Firstly, the framework employs a CNN-LSTM hybrid model (WOA-CNN-LSTM) optimized using the whale optimization algorithm to achieve real-time detection of false data injection attacks (FDIAs) and post-attack data recovery. By deeply mining the spatiotemporal characteristics of the measured data, the framework effectively identifies anomalies and repairs tampered data. Subsequently, based on the improved multi-objective whale optimization algorithm (IMOWOA), rapid optimization scheduling is conducted to ensure that the system can maintain an optimal operational state following an attack. Simulation results demonstrate that the proposed framework achieves a detection accuracy of 0.9864 and a recovery efficiency of 0.969 for anomaly data. Additionally, it reduces the ship’s operating cost, power loss, and carbon emissions by at least 1.96%, 5.67%, and 1.65%, respectively. Full article

This study presents a multi-objective predictive energy management system (EMS) for optimizing hybrid renewable energy systems (HRES) in autonomous marine vessels. The objective is to minimize fuel consumption and emissions while maximizing renewable energy usage and pure-electric sailing durations. The EMS combines nonlinear model predictive control (NMPC) with metaheuristic optimizers—Grey Wolf Optimization (GWO) and Genetic Algorithm (GA)—and is benchmarked against a conventional rule-based (RB) method. The HRES architecture comprises photovoltaic arrays, vertical-axis wind turbines (VAWTs), diesel engines, generators, and a battery storage system. A ship dynamics model was used to represent propulsion power under realistic sea conditions. Simulations were conducted using real-world operational and environmental datasets, with state prediction enhanced by an Extended Kalman Filter (EKF). Performance is evaluated using marine-relevant indicators—fuel consumption; emissions; battery state of charge (SOC); and emission cost—and validated using standard regression metrics. The NMPC-GWO algorithm consistently outperformed both NMPC-GA and RB approaches, achieving high prediction accuracy and greater energy efficiency. These results confirm the reliability and optimization capability of predictive EMS frameworks in reducing emissions and operational costs in autonomous maritime operations. Full article

Few studies have examined Hybrid Aquatic–Aerial Vehicles (HAAVs), autonomous vehicles designed to operate in both air and water, especially those that are aircraft-launched and recovered, with a variable-sweep design to free dive into a body of water and breach under buoyant and propulsive force to re-achieve flight. The novel design research examines the viability of a recoverable sonar-search child aircraft for maritime patrol, one which can overcome the prohibitive sea state limitations of all current HAAV designs in the research literature. This paper reports on the analysis from computational fluid dynamic (CFD) simulations of such an HAAV diving into static seawater at low speeds due to the reverse thrust of two retractable electric-ducted fans (EDFs) and its subsequent breach back into flight initially using a fast buoyancy engine developed for deep-sea research vessels. The HAAV model entered the water column at speeds around 10 ms⁻¹ and exited at 5 ms⁻¹ under various buoyancy cases, normal to the surface. Results revealed that impact force magnitudes varied with entry speed and were more acute according to vehicle mass, while a sufficient portion of the fuselage was able to clear typical wave heights during its breach for its EDF propulsors and wings to protract unhindered. Examining the medium transition dynamics of such a novel HAAV has provided insight into the structural, propulsive, buoyancy, and control requirements for future conceptual design iterations. Research is now focused on validating these unperturbed CFD dive and breach cases with pool experiments before then parametrically and numerically examining the effects of realistic ocean sea states. Full article

This paper develops a model to calculate carbon emissions during the construction period of dredging projects. Carbon emission quotas for various types of dredgers and auxiliary vessels in different construction conditions and geotechnical soil types during the dredging project’s construction period are established, as well as the power consumption quota for management activities. Taking the construction of the main project of the cross-river channel from Shenzhen to Zhongshan (S09)’s foundation trench excavation and channel dredging, the Thilafushi Island reclamation project in Malé, and the second phase of the southern section of the Guangzhou Port Area channel maintenance project (2022–2023) as case studies, the validity of the quotas is verified. During the construction period, under the same dredging soil quality and the same working condition level, the carbon emissions of different types of dredgers are different. Conversely, under different dredging soil qualities and different working condition levels, the carbon emissions for the same dredger or auxiliary vessel are different. The carbon emissions of each dredger or auxiliary vessel increase with the increase in the ship’s specifications. The carbon emissions of dredging projects are huge, with direct carbon emissions accounting for 97%, and indirect carbon emissions from equipment deployment and management activities accounting for 3%, among which the carbon emissions from electricity consumption in management activities account for only 0.3%. Full article

This study develops a one-pot anodic templating electrodeposition strategy using dual-cation-crosslinking and interpenetrating networks, coupled with pulsed electrical signals, to fabricate a vessel-mimetic multilayered tubular hydrogel. Typically, the anodic electrodeposition is performed in a mixture of sodium alginate (SA) and carboxymethyl chitosan (CMC), with the ethylenediaminetetraacetic acid calcium disodium salt hydrate (EDTA·Na₂Ca) incorporated to provide a secondary ionic crosslinker (i.e., Ca²⁺) and modulate the cascade reaction diffusion process. The copper wire electrodes serve as templates for electrochemical oxidation and enable a copper ion (i.e., Cu²⁺)-induced tubular hydrogel coating formation, while pulsed electric fields regulate layer-by-layer deposition. The dual-cation-crosslinked interpenetrating hydrogels (CMC/SA-Cu/Ca) exhibit rapid growth rates and tailored mechanical strength, along with excellent antibacterial performance. By integrating the unique pulsed electro-fabrication with biomimetic self-assembly, this study addresses challenges in vessel-mimicking structural complexity and mechanical compatibility. The approach enables scalable production of customizable multilayered hydrogels for artificial vessel grafts, smart wound dressings, and bioengineered organ interfaces, demonstrating broad biomedical potential. Full article

The implementation of hybrid propulsion systems in vessels has gained prominence due to their significant advantages in energy efficiency and their reduction in harmful emissions, particularly during low engine load operations. This study evaluates hybrid propulsion system applications in two different tugboats, focusing on fuel consumption and engine load across eight distinct operational scenarios, including Istanbul Strait crossings and towing and pushing manoeuvres. The scenarios incorporate asynchronous electric motors with varying power ratings, lead-acid and lithium iron phosphate batteries with distinct storage capacities, and photovoltaic panels of different sizes. The highest fuel savings of 72.4% were recorded in the second scenario, which involved only towing and pushing operations using lithium iron phosphate batteries. In contrast, the lowest fuel savings of 5.2% were observed in the sixth scenario, focused on a strait crossing operation employing lead-acid batteries. Although integrating larger-scale batteries into hybrid propulsion systems is vital for extended ship operations, their adoption is often limited by space and weight constraints, particularly on tugboats. Nevertheless, ongoing advancements in hybrid system technologies are expected to enable the integration of larger, more efficient systems, thereby enhancing fuel-saving potential. Full article

Recently, as carbon emission regulations enforced by the International Maritime Organization (IMO) have become stricter and pressure from the World Trade Organization (WTO) to abolish tax-free fuel subsidies has increased, the demand for electric propulsion systems in the marine sector has grown. Most small domestic fishing vessels rely on tax-free fuel and have limited cruising ranges and constant-speed operation, which makes them well-suited for electric propulsion. This paper proposes replacing the internal combustion engine system of such vessels with an electric propulsion system. Based on real operating conditions, an Interior Permanent Magnet Synchronous Motor (IPMSM) was designed and optimized. The Savitsky method was used to calculate total resistance at a typical cruising speed, from which the required torque and output were determined. To reduce torque ripple, an asymmetric dummy slot structure was proposed, with two dummy slots of different widths and depths placed in each stator slot. These dimensions, along with the magnet angle, were set as optimization parameters, and a metamodel-based optimal design was carried out. As a result, while meeting the design constraints, torque ripple decreased by 2.91% and the total harmonic distortion (THD) of the back-EMF was lowered by 1.32%. Full article

In the aerospace, energy and nuclear energy sectors, dynamic pressure measurement of power equipment and pressure vessels in high-temperature environments is critical for validating design, manufacturing processes and operational condition monitoring. The existing electric sensors are resistant to temperature. It is difficult to meet the pressure measurement requirements of high temperature and high-frequency responses. In this paper, combining the material properties of high-temperature co-fired ceramics (HTCC) with the structural characteristics of Fabry–Perot, an all-ceramic fiber-optic Fabry–Perot high-temperature pulsating pressure sensor based on a HTCC pressure- sensing diaphragm and ceramic high-temperature sintering process, is proposed. Experimental results show that in the pressure range of 6 MPa, the static pressure sensitivity of the sensor is 1.30 nm/MPa, and the linear goodness of fit reaches 0.99913. The dynamic response frequency of the sensor reaches 598.5 kHz. The survival time at high temperature of 800 °C is more than 80 h. The sensitivity to temperature is 0.00475 nm/°C. Full article

Atrial fibrillation (AF), the most prevalent clinically significant cardiac arrhythmia, is characterized by chaotic atrial electrical activity and currently affects an estimated 2.5–3.5% of the global population. Its pathogenesis involves ion channel dysfunction, inflammatory cascades, and structural remodeling processes, notably fibrosis. Angiogenesis, the physiological/pathological process of new blood vessel formation, plays a multifaceted role in AF progression. This review synthesizes evidence highlighting angiogenesis’s dual role in AF pathogenesis: while excessive or dysregulated angiogenesis promotes atrial remodeling through fibrosis, and electrical dysfunction via VEGF, ANGPT, and FGF signaling pathways, compensatory angiogenesis exerts protective effects by improving tissue perfusion to alleviate ischemia and inflammation. Therapeutically, targeting angiogenic pathways—particularly VEGF—represents a promising strategy for modulating structural remodeling; however, non-selective VEGF inhibition raises safety concerns due to cardiovascular toxicity, necessitating cautious exploration. Emerging evidence highlights that anti-cancer agents (e.g., ibrutinib, bevacizumab) impair endothelial homeostasis and elevate AF risk, underscoring the need for cardio-oncology frameworks to optimize risk–benefit ratios. Preclinical studies on angiogenesis inhibitors and gene therapies provide mechanistic insights, but clinical validation remains limited. Future research should prioritize elucidating mechanistic complexities, developing biomarker refinement, and implementing interdisciplinary strategies integrating single-cell sequencing with cardio-oncology principles. This review emphasizes the imperative to clarify angiogenic mechanisms, optimize therapeutic strategies, and balance pro-arrhythmic versus compensatory angiogenesis, in pursuit of personalized AF management. Full article

The decommissioning of the Zion Nuclear Power Plant (NPP) provided a unique opportunity to harvest and study service-aged reactor pressure vessel (RPV) beltline materials. This work, conducted through the U.S. Department of Energy’s Light Water Reactor Sustainability (LWRS) Program, aims to improve the understanding of radiation-induced embrittlement to support extended nuclear plant operations. Material segments containing the Linde 80 flux, wire heat 72105 (WF-70) beltline weld and the A533B Heat B7835-1 base metal, obtained from the intermediate shell region with a peak fluence of 0.7 × 10¹⁹ n/cm² (E > 1.0 MeV), were extracted, cut into blocks, and machined into test specimens for mechanical and microstructural characterization. The segmentation process involved oxy-propane torch-cutting, followed by precision machining using wire saws and electrical discharge machining (EDM). A chemical composition analysis confirmed the expected variations in alloying elements, with copper levels being notably higher in the weld metal. The harvested specimens enable a detailed evaluation of through-wall embrittlement gradients, a comparison with the existing surveillance data, and the validation of predictive embrittlement models. This study provides critical data for assessing long-term reactor vessel integrity, informing aging-management strategies, and supporting regulatory decisions to extend the life of nuclear plants. This article is a revised and expanded version of a paper entitled, “Current Status of the Characterization of RPV Materials Harvested from the Decommissioned Zion Unit 1 Nuclear Power Plant”, PVP2017-65090, which was accepted and presented at the ASME 2017 Pressure Vessels and Piping Conference, Waikoloa, HI, USA, 16–20 July 2017. Full article

To address the challenge of detecting low-frequency electric field signals from vessels in complex marine environments, a vessel shaft frequency electric field feature extraction method based on intrinsic mode function energy arrangement entropy values is proposed, building upon a scaled model. This study initially establishes a measurement system for shaft frequency electric fields, utilizing a titanium-based oxide electrode to construct an equivalent dipole source simulating the shaft frequency electric field signals of different types of vessels. Subsequently, a comparative analysis of the time-domain and frequency-domain characteristics of signals after modal decomposition is conducted. A feature extraction method is then proposed that combines the maximum average energy of intrinsic mode functions with arrangement entropy values to achieve discrimination of target signals. Finally, the feasibility of the proposed method is validated through sea trials. The results indicate that the method can successfully screen different types of typical vessels and address the target screening failure caused by slight differences in the characteristic parameters of the shaft frequency electric field signal. The entropy difference has been improved from 0.05 to about 0.2, and the difference rate of the shaft frequency electric field signal has been improved by 75%. This has effectively reduced the false alarm rate of target detection. Full article