Search Results (364)

This work presents an analysis of the sub-ionospheric VLF transmitter signal disturbances which were detected more than one week before the Turkey–Syria EQ occurrence. We have applied the multi-terminator method when considering amplitude and phase variations of the TBB transmitter signal (Turkey), selected because of a good signal to noise ratio for the amplitude, a stable phase variation, and a ray-path propagation crossing the pre-seismic sensitive region, estimated from the combination of the Dobrovolsky area and the Fresnel zone. New spectral features, i.e., inflexions and jumps, are considered in this study, besides the minima and maxima investigated in. The spectral occurrence probabilities are derived at three specific locations: Graz facility, TBB station and EQ epicenter. We show that two main precursors occurred from 27 to 30 January, and from 31 January to 3 February. More important are the prior precursors detected from 23 January to 25/26 January, where anomaly fluctuations were found to be similar to those at the EQ epicenter area, approximately. A forecasting model is proposed, in which the main steps can provide, in the presence of spectral anomalies, first hints regarding the longitudinal locations of the seismic preparation zone. Full article

Onboard Vehicle-to-Everything (V2X) communication technology is being widely implemented in domains such as intelligent driving, vehicle–road cooperation, and smart transportation. Nevertheless, time synchronization in V2X systems suffers from instability due to the random loss of Global Navigation Satellite System (GNSS) Pulse-Per-Second (PPS) signals. To address this challenge, a model-driven local clock correction approach is proposed. Leveraging probability theory and mathematical statistics, models for the randomly lost GNSS PPS signals are developed. High-order polynomials are used to model local clocks. An optimized Kalman-filter-based time compensation algorithm is then devised to compensate for time errors during PPS signal loss. A software-based task-scheduling solution for precision-time synchronization is developed. An experimental testbed was then built to measure both terminal clocks and PPS signals. The proposed algorithm was integrated into the V2X terminals. Results show that the full-value PPS signals follow an exponential distribution. The onboard clock correction algorithm operates stably across three V2X terminals and accurately predicts clock variations. Furthermore, the virtual clocks achieve an average absolute error of 1.1 μs and a standard deviation of 16 μs, meeting the time synchronization requirements for V2X communication in intelligent connected vehicles. Full article

Cognitive impairment in subjects with Alzheimer’s disease correlates well with the loss of synaptic plasticity. This results from mitochondrial dysfunction and production of reactive oxygen species, which damage nerve terminals causing them to release ATP and adenosine. These purines activate receptors on microglia resulting in a change in morphology and release proinflammatory cytokines that exacerbate neuronal damage. The review describes retrospective studies with naturally occurring antioxidants, vitamin E, resveratrol, Ginkgo biloba and others that suggested they reduce the incidence of Alzheimer’s disease. They have antioxidant activity in cellular systems and rodent models, but most of them failed in clinical trials, probably because they were not absorbed after oral administration or, like anti-inflammatory drugs, were not given at the right time or for long enough to detect an effect on disease progression. Ladostigil is an aminoindan derivative that is well absorbed after oral administration. It has antioxidant effects in cells and prevents cytokine release from activated microglia. In a phase 2 trial in subjects with mild cognitive impairment, ladostigil significantly reduced number of converters to Alzheimer’s disease in ApoE4-ve subjects and delayed the decline in whole brain and hippocampal volumes without causing adverse effects related to drug intake. Full article

In this paper, we investigate a simultaneous wireless information and power transfer (SWIPT) communication system enhanced by an intelligent reflecting surface (IRS). Our study takes into account the imperfections in the phase shift of the IRS and the presence of interfering signals reflected by the IRS at the destination terminal. Additionally, our analysis incorporates both the presence of a line-of-sight path between the source and destination and a non-linear energy-harvesting model. In order to assess the influence of phase error and interference on the considered system, closed-form and asymptotic expression for the system’s outage probability, ergodic capacity, and energy efficiency (EE) are derived. Simulation results are presented to corroborate our analysis and illustrate the impact of phase error, interference, the number of reflecting elements, and various system parameters on the system performance. Full article

Alginate oligosaccharide (AOS), a degradation product of alginate derived from marine brown algae, has attracted significant attention due to its potent ability to modulate gut microbiota and enhance human health. This review aims to systematically introduce current evidence on the interactions between AOS and gut microbial communities, focusing on how AOS improves health through regulating gut microbiota. Initially, the structural factors of AOS that influence their functions are highlighted, including molecular weight, monomer composition, terminal structure, and chemical modifications. Importantly, AOS primarily exerts beneficial effects by adjusting gut microbiota community and outputs, which include the promotion of probiotics, the inhibition of pathogens, the balance of microbiota composition, and the increase of short-chain fatty acid production. Moreover, the discovered mechanisms underlying AOS-mediated health promotion via microbiota modulation are detailed comprehensively, specifically emphasizing intestinal barrier maintenance, antioxidation, dual-regulation of immune and inflammatory responses, pathogenic infection inhibition, metabolic improvement, uric acid excretion promotion, anti-tumor effects, and anti-skin aging. Such beneficial effects make AOS valuable in keeping healthy, preventing disorders, and intervening in diseases. Despite these findings and research progress, there are yet limitations in studying AOS–gut microbiota interactions, such as precise microbiota-targeted structural optimization, personalized nutritional interventions based on microbial characteristics, and broadening the horizon of microbiota-derived metabolic metabolomic profiles. In conclusion, advancing our understanding of the gut microbiota-centered mechanisms of AOS would probably facilitate novel nutritional strategy development for health promotion. Full article

A three-terminal graph is defined as a simple graph comprising three specified target vertices. The reliability of three-terminal graphs represents the probability that these three target vertices remain connected, given that each edge fails independently with a constant probability q. In this paper, we focus on exploring the characteristics of more reliable three-terminal graphs when the edge failure probability approaches 1. Three reliability comparison criteria are proposed to characterize the locally most reliable three-terminal graph progressively when the number of edges m is in the range of $[5,4n-10]$ and $[\left({\displaystyle \genfrac{}{}{0pt}{}{n}{2}}\right)-n+4,\left({\displaystyle \genfrac{}{}{0pt}{}{n}{2}}\right)]$. At the same time, the locally optimal structures in the range of the edge number m with $(4n-10,\left({\displaystyle \genfrac{}{}{0pt}{}{n}{2}}\right)-n+4)$ are restricted to six specific classes of graphs. Furthermore, based on these criteria, a method is introduced to search local optimal structures and offer a theoretical foundation for constructing optimal networks and repairing faulty ones. Full article

Objective: To evaluate the economic impact associated with the use of specific brain biomarkers glial fibrillary acid protein (GFAP) and ubiquitin C-terminal hydrolase L1 (UCH-L1) in adult patients with suspected mild traumatic brain injury (TBI) in a standard Spanish hospital setting. Methods: We used a budget impact analysis (BIA) to compare the cost of standard of care using head computed tomography (CT) to evaluate intracranial injury with a scenario incorporating specific biomarkers GFAP and UCH-L1 in an estimated population of 3500 adult patients attending the hospital emergency department with a score of 13 to 15 on the Glasgow Coma Scale (GCS). The probabilities associated with clinical procedures were obtained from a multidisciplinary group of experts from Spanish hospitals and supplemented with data from the literature. Costs were estimated using hospital tariffs from the Spanish autonomous communities and other official sources. Results: The incorporation of specific biomarkers GFAP and UCH-L1 in the management of mild TBI could generate an estimated annual savings of EUR 696,634 in a standard Spanish hospital, mainly due to reduced CT use. The average savings per patient would be EUR 199.04, and the care time would be reduced by 111 min. Sensitivity analysis, with variations of ±20% in the parameters, confirms these savings. Conclusions: This study suggests that the use of specific biomarkers GFAP and UCH-L1 in the management of mild TBI patients in Spain could reduce the average cost per patient, generating significant savings for hospitals. Future studies that incorporate data from clinical records will help validate these results. Full article

Status epilepticus (SE) is a neurological emergency. Current evidence dictates a step-by-step approach with a first line of therapy consisting of benzodiazepines (BDZs). In many situations, the currently approved approach does not terminate a BDZ-resistant SE. This happens in Stage 1 Plus, a framework designed by the author to recognize cases of probable benzodiazepine-resistant status epilepticus even before treatment initiation. These cases include Prolonged SE (SE lasting > 10 min), the absence of prominent motor phenomena, and acute etiology (primary central nervous system etiologies most of all). BDZ-refractory SE cases (Stage 1 Plus) might require a different approach, one targeting the unresponsive GABA signaling state mediated by NMDA/AMPA receptors, such as combined polytherapy with Ketamine from the start. These considerations stem from the receptor trafficking hypotheses: in prolonged seizure activity and primary central nervous system etiologies, GABA receptors get internalized and move away from synapses, and therefore, SE becomes resistant to BDZ. A rational polytherapy that might restore the unresponsiveness to BDZ in SE should include NMDA antagonists, such as Ketamine. Ketamine has proven effective in many experimental models of status epilepticus, and much evidence is gathering supporting its use in humans, especially in refractory and super-refractory SE. We lack studies evaluating combined polytherapy in SE, especially in the early phases. The author suggests here that Ketamine should be used along with first-line BDZ in the early SE stage falling in the category of Stage 1 Plus and as a first-line anesthetic infusion drug in refractory SE, especially in cases progressing from Stage 1 Plus, eventually adding continuous midazolam/propofol infusion in later phases. This systematic review’s objective is to summarize the presently available evidence of the early use of combined polytherapy that includes Ketamine, along with the currently available evidence of Ketamine use in early, established, and refractory SE. Nine studies were included. Boluses of Ketamine and Midazolam are effective in pediatric convulsive Stage 1 Plus SE. The results show that earlier Ketamine administration (especially within 12 h of SE onset) was significantly associated with improved seizure control, with a more favorable safety profile than Midazolam in refractory SE. Notably, a dosage of less than 0.9 mg/kg/h proves ineffective in terminating SE. Ketamine has the advantage of preventing intubation, possibly shortening the length of stay in the intensive care unit. Full article

To address the challenges of detection and acquisition caused by trajectory prediction errors during the midcourse–terminal guidance handover phase in cross-domain unmanned aerial vehicles (CDUAV), this study proposes a collaborative multi-interceptor detection coverage optimization method based on predictive error pipeline modeling. Firstly, we employ nonlinear least squares to fit parameters for the motion model of CDUAV. By integrating error propagation theory, we derive a recursive expression for error pipelines under t-distribution and establish a parametric model for the target’s high-probability region (HPR). Next, we analyze target acquisition scenarios during guidance handover and reformulate the collaborative detection problem as a field-of-view (FOV) coverage optimization task on a two-dimensional detection plane. This framework incorporates the target HPR and the seeker detection FOV models, with an objective function defined for coverage optimization. Finally, inspired by wireless sensor network (WSN) coverage strategies, we implement the starfish optimization algorithm (SFOA) to enhance computational efficiency. Simulation results demonstrate that compared to Monte Carlo statistical methods, our parametric modeling approach reduces prediction error computation time from 15.82 s to 0.09 s while generating error pipeline envelopes with 99% confidence intervals, showing superior generalization capability. The proposed collaborative detection framework effectively resolves geometric coverage optimization challenges arising from mismatches between target HPR and FOV morphology, exhibiting rapid convergence and high computational efficiency. Full article

This paper proposes an optimization strategy for Feeder Terminal Unit (FTU) configuration in distribution networks, accounting for the influence of Distributed Generation (DG). Firstly, the impact of different FTU configurations on load interruption duration was analyzed. Regions were divided based on the planned installation locations of FTUs, and a model for calculating load interruption losses in different regions was established. Secondly, an all-probability model was introduced to calculate the probability of DG disconnection during faults. The importance weight of DG was determined based on its capacity, and a loss model for photovoltaic disconnection was constructed accordingly. Then, an optimization configuration model was established with the objective of minimizing the weighted sum of FTU installation costs, load interruption losses, and DG disconnection losses, while constraining the solution by supply reliability. Finally, the accuracy of the proposed optimization model was validated using Particle Swarm Optimization (PSO) through the IEEE 33-node distribution network model. Full article

The latest Versatile Video Coding(H.266/VVC) standard introduces the QTMT structure, enabling more flexible block partitioning and significantly enhancing coding efficiency compared to its predecessor, High-Efficiency Video Coding (H.265/HEVC). However, this new structure results in changes to the size of Coding Units (CUs). To accommodate this, VVC increases the number of intra-prediction modes from 35 to 67, leading to a substantial rise in computational demands. This study presents a fast intra-prediction mode selection algorithm that combines gradient analysis and CNN. First, the Laplace operator is employed to estimate the texture direction of the current CU block, identifying the most probable prediction direction and skipping over half of the redundant candidate modes, thereby significantly reducing the number of mode searches. Second, to further minimize computational complexity, two efficient neural network models, MIP-NET and ISP-NET, are developed to determine whether to terminate the prediction process for Matrix Intra Prediction(MIP) and Intra Sub-Partitioning(ISP) modes early, avoiding unnecessary calculations. This approach maintains coding performance while significantly lowering the time complexity of intra-prediction mode selection. Experimental results demonstrate that the algorithm achieves a 35.04% reduction in encoding time with only a 0.69% increase in BD-BR, striking a balance between video quality and coding efficiency. Full article

von Willebrand factor (vWF) is a large glycoprotein in the circulation system, which senses hydrodynamic force at vascular injuries and then recruits platelets in assembling clots. How vWF mechanosenses shear flow for molecular unfolding is an important topic. Here, a Förster resonance energy transfer (FRET) biosensor was developed to monitor vWF conformation change to hydrodynamic force. The vWF-based biosensor is anchored on the cell surface, in which the A2 domain is flanked with a FRET pair. With 293T cells seeded into microfluidic channels, 2.8 dyn/cm² of shear force (i.e., 28 μN/cm², or 264.1/s in shear rate) induced a remarkable FRET change (~60%) in 30 min. A gradient micro-shear below 2.8 dyn/cm² demonstrated FRET responses positively related to flow magnitudes, with 0.14 dyn/cm² (1.4 μN/cm²) inducing an obvious change (~16%). The FRET increases indicate closer positioning of A2’s two terminals in vWF or the addition of a more parallel orientation of the FRET pair, supported with the high FRET of the A2-only-based biosensor, which probably resulted from flow-induced A2 dissociation from vWF intramolecular binding such as that in A1/A3 domains. Interestingly, gradient flow increases from 2.8 to 28 dyn/cm² led to decreasing FRET changes, suggesting the second-level unfolding in the A2 domain. The LOCK-vWF biosensor with bridged A2 two terminals or an A2-only biosensor could not sense the shear, indicating a structure-flexible A2 and large vWF molecules that are important in the mechanosensation. In conclusion, the developed vWF-based biosensor demonstrated the high mechanosensation of vWF with two-level unfolding to shear force: the dissociation of the A2 domain from vWF intramolecular binding under a micro-shear, and then the unfolding of A2 in vWF under a higher shear; the FRET response to shear force at a very low scale may support the observed clot formation at microvascular wounds. This study provides new insights into the vWF’s mechanosensitive feature for its physiological functions and implicated disorders. Full article

This paper investigates the outage performance of simultaneous wireless information and power transfer (SWIPT)-assisted device-to-device (D2D)-based hybrid satellite–terrestrial networks (HSTNs). In the considered system, an energy-constrained terrestrial user terminal (UT) harvests energy from the radio frequency (RF) signal of a terrestrial amplify-and-forward (AF) relay and utilizes the harvested energy to cooperate with the shadowed terrestrial Internet of Things (IoT) devices in a D2D communication. Both power splitting (PS)-based and time switching (TS)-based SWIPT-D2D schemes are adopted by the energy-constrained UT to obtain sustainable energy for transmitting information to the shadowed IoT device. Considering shadowed Rician fading for satellite–terrestrial links and Nakagami-m fading for terrestrial links, we analyze the system performance by deriving the closed-form expressions for the outage probability (OP) of both the UT and the IoT device. Our theoretical analyses are validated via Monte Carlo simulations. Full article

Space-to-ground laser communication (SGLC) offers a paradigm-shifting solution to overcome the bandwidth constraints of radio frequency systems by leveraging laser beams for ultra-high data throughput, although its link availability probability is significantly affected by atmospheric conditions such as cloud cover. Existing ground station (GS) placement methods decouple site selection from downlink scheduling, failing to effectively quantify the data throughput of candidate sites. This study proposes a data throughput-driven joint optimization framework that integrates downlink scheduling into the site selection model for the first time. Additionally, the site selection model also incorporates equipment cost constraints and service capacity limitations by introducing an integer variable Q to characterize the deployment scale of laser communication terminals (LCTs) at each GS. Through auxiliary variable linearization techniques, the site selection problem is transformed into a tractable integer linear programming (ILP) formulation. A branch-and-bound algorithm is proposed to achieve global optimal solution search. Numerical results demonstrate that the proposed approach improves data throughput compared to the existing method. Full article

We consider a queuing system with a finite number of servers and a finite pool of resources, where an arriving customer requires a server and random number of resources. During the service, each customer is associated with a Poisson flow of “signals”, where upon a signal arrival, the currently allocated resources for a customer are released, and an attempt is made to allocate a new random amount of resources. Recently, such systems have received significant attention for their use in the analysis of 5G/6G cellular systems with non-elastic traffic demands and blockage impairments. Such queuing systems do not allow closed-form analytical solutions, and are conventionally solved using numerical methods. These methods are sensitive to the dimensions of the state space and can lead to inaccuracies. In this paper, we propose a new method for the approximate analysis of performance metrics in resource systems with signals using analytical solutions for similar systems without signals. Our detailed comparison with simulations shows that the relative error is limited to 5–10% over a wide range of system and load parameters. Full article