Search Results (357)

The ATLAS lidar on NASA’s Earth-orbiting ICESat-2 satellite has operated continuously since its launch in September 2018, with no sign of degradation. Compared to previous international single-beam spaceborne lidars, which operated at a few tens of Hz, the single-photon-sensitive, six-beam ATLAS pushbroom lidar provides 60,000 surface measurements per second and has accumulated almost 3 trillion surface measurements during its six years of operation. It also features a 0.5 m² telescope aperture and a single, 5 Watt, frequency-doubled Nd:YAG laser generating a 10 KHz train of 1.5-nanosecond pulses at a green wavelength of 532 nm. The current paper investigates how, with minor modifications to the ATLAS lidar, this capability might be extended to other planets within our solar system. Crucial to this capability is the need to minimize the solar background seen by the lidar while simultaneously providing, for long time intervals (multiple months), an uninterrupted, modestly powered, multimegabit per second interplanetary laser communications link to a terminal in Earth orbit. The proposed solution is a pair of Earth and planetary satellites in high, parallel, quasi-synchronized orbits perpendicular to their host planet’s orbital planes about the Sun. High orbits significantly reduce the time intervals over which the interplanetary communications link is blocked by their host planets. Initial establishment of the interplanetary communications link is simplified during two specific time intervals per orbit when the sunlit image of the two planets are not displaced from their actual positions (“zero point ahead angle”). In this instance, sunlit planetary images and the orbiting satellite laser beacon can be displayed on the same pixelated detector array, thereby accelerating the coalignment of the two communication terminals. Various tables in the text provide insight for each of the eight planets regarding the impact of solar distance on the worst-case Signal-to-Noise Ratio (SNR), the effect of satellite orbital height on the duration of the unblocked interplanetary communications link, and the resulting planetary surface continuity and resolution in both the along-track and cross-track directions. For planets beyond Saturn, the laser power and/or transmit/receive telescope apertures required to transmit multimegabit-per-second lidar data back to Earth are major challenges given current technology. Full article

Aiming at the speed chattering problem caused by high-frequency square wave injection in permanent magnet synchronous motors (PMSMs) during low-speed operation (200–500 r/min), this study intends to improve the rotor position estimation accuracy of sensorless control systems as well as the system’s ability to resist harmonic interference and sudden load changes. The goal is to enhance the control performance of traditional control schemes in this scenario and meet the requirement of stable low-speed operation of the motor. First, the study analyzes the harmonic error propagation mechanism of high-frequency square wave injection and finds that the traditional PI phase-locked loop (PI-PLL) is susceptible to high-order harmonic interference during demodulation, which in turn leads to position estimation errors and periodic speed fluctuations. Therefore, the extended state observer phase-locked loop (ESO-PLL) is adopted to replace the traditional PI-PLL. A third-order extended state observer (ESO) is used to uniformly regard the system’s unmodeled dynamics, external load disturbances, and harmonic interference as “total disturbances”, realizing real-time estimation and compensation of disturbances, and quickly suppressing the impacts of harmonic errors and sudden load changes. Meanwhile, a dynamic pole placement strategy for the speed loop is designed to adaptively adjust the controller’s damping ratio and bandwidth parameters according to the motor’s operating states (loaded/unloaded, steady-state/transient): large poles are used in the start-up phase to accelerate response, small poles are switched in the steady-state phase to reduce errors, and a smooth attenuation function is used in the transition phase to achieve stable parameter transition, balancing the system’s dynamic response and steady-state accuracy. In addition, high-frequency square wave voltage signals are injected into the dq axes of the rotating coordinate system, and effective rotor position information is extracted by combining signal demodulation with ESO-PLL to realize decoupling of high-frequency response currents. Verification through MATLAB/Simulink simulation experiments shows that the improved strategy exhibits significant advantages in the low-speed range of 200–300 r/min: in the scenario where the speed transitions from 200 r/min to 300 r/min with sudden load changes, the position estimation curve of ESO-PLL basically overlaps with the actual curve, while the PI-PLL shows obvious deviations; in the start-up and speed switching phases, dynamic pole placement enables the motor to respond quickly without overshoot and no obvious speed fluctuations, whereas the traditional fixed-pole PI control has problems of response lag or overshoot. In conclusion, the “ESO-PLL + dynamic pole placement” cooperative control strategy proposed in this study effectively solves the problems of harmonic interference and load disturbance caused by high-frequency square wave injection in the low-speed range and significantly improves the accuracy and robustness of PMSM sensorless control. This strategy requires no additional hardware cost and achieves performance improvement only through algorithm optimization. It can be directly applied to PMSM control systems that require stable low-speed operation, providing a reliable solution for the promotion of sensorless control technology in low-speed precision fields. Full article

Transformer-based models have accelerated EEG motor imagery (MI) decoding by using self-attention to capture long-range temporal structures while complementing spatial inductive biases. This systematic survey of Scopus-indexed works from 2020 to 2025 indicates that reported advances are concentrated in offline, protocol-heterogeneous settings; inconsistent preprocessing, non-standard data splits, and sparse efficiency frequently reporting cloud claims of generalization and real-time suitability. Under session- and subject-aware evaluation on the BCIC IV 2a/2b dataset, typical performance clusters are in the high-80% range for binary MI and the mid-70% range for multi-class tasks with gains of roughly 5–10 percentage points achieved by strong hybrids (CNN/TCN–Transformer; hierarchical attention) rather than by extreme figures often driven by leakage-prone protocols. In parallel, transformer-driven denoising—particularly diffusion–transformer hybrids—yields strong signal-level metrics but remains weakly linked to task benefit; denoise → decode validation is rarely standardized despite being the most relevant proxy when artifact-free ground truth is unavailable. Three priorities emerge for translation: protocol discipline (fixed train/test partitions, transparent preprocessing, mandatory reporting of parameters, FLOPs, per-trial latency, and acquisition-to-feedback delay); task relevance (shared denoise → decode benchmarks for MI and related paradigms); and adaptivity at scale (self-supervised pretraining on heterogeneous EEG corpora and resource-aware co-optimization of preprocessing and hybrid transformer topologies). Evidence from subject-adjusting evolutionary pipelines that jointly tune preprocessing, attention depth, and CNN–Transformer fusion demonstrates reproducible inter-subject gains over established baselines under controlled protocols. Implementing these practices positions transformer-driven BCIs to move beyond inflated offline estimates toward reliable, real-time neurointerfaces with concrete clinical and assistive relevance. Full article

Adventitious rooting is a key step for the clonal propagation of many economically important horticultural and woody species. Accumulating evidence suggests that nitric oxide (NO) serves as a key signaling molecule with key roles in root organogenesis. However, the role of NO in adventitious root development and its underlying mechanism in sweetpotato cuttings remain to be clarified. In this study, a pot experiment was conducted using hydroponically cultured sweetpotato cuttings (Ipomoea batatas cv. ‘Jin Ganshu No. 9’) treated with different concentrations of sodium nitroprusside (SNP, an NO donor) solution (0, 10, 50, 100, 200, and 500 μmol·L⁻¹). Three treatments were established: Control, SNP (the optimal concentration of SNP), and SNP + 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO, an NO scavenger). The results showed that NO promoted adventitious rooting in a dose-dependent manner, with the maximal biological response observed at 100 μM SNP. At this concentration, the root number and length of adventitious roots increased by 1.22 and 2.36 times, respectively, compared to the control. SNP treatment increased fresh root weight, dry root weight, the content of soluble sugar, soluble protein, chlorophyll a (Chl a), chlorophyll b (Chl b), and total chlorophyll (a + b) [Chl(a + b)], as well as the activities of peroxidase (POD), polyphenol oxidase (PPO), and indole acetic acid oxidase (IAAO). It also enhanced the levels of maximum fluorescence (Fm), maximum photochemical efficiency of photosystem II (Fv/Fm), absorbed light energy (ABS/RC), trapped energy flux (TRo/RC), and electron transport flux (ETo/RC), while decreasing starch content and initial fluorescence (Fo). On the 7th day, the SNP treatment significantly enhanced several biochemical parameters compared to the control. We observed an increase in many of the parameters: POD activity by 1.35 times, PPO activity by 0.55 times, chlorophyll content (Chl a by 0.66 times, Chl b by 0.22 times, and Chl a + b by 0.57 times), and photosynthesis parameters by 28–98%. Meanwhile, starch content and Fo in the SNP treatment decreased by 10.77% and 23.86%, respectively, compared to the control. Furthermore, the positive effects of NO on adventitious root development and associated biochemical parameters were reversed by the NO scavenger cPTIO. Additionally, significant and positive correlations were observed between morphological characteristics and most physiological indicators. Collectively, these results demonstrate that NO promotes adventitious root formation, which may be by enhancing rooting-related enzyme activities, improving photosynthetic performance in leaves, and accelerating the metabolism of soluble sugar, soluble protein, and starch. Full article

Immunosenescence, defined as the progressive decline of immune function with age, is increasingly recognized as a determinant of morbidity in people living with HIV (PLWH) and in individuals with metabolic dysfunction. The coexistence of chronic viral infection and systemic metabolic alterations—including metabolic dysfunction-associated steatotic liver disease (MASLD) and type 2 diabetes mellitus—creates a pro-inflammatory state (“metaflammation”) that accelerates immune aging. This narrative review synthesizes current clinical, translational, and experimental evidence on the cellular, molecular, and metabolic mechanisms underlying immunosenescence in HIV-positive and HIV-negative populations with metabolic dysfunction. Key converging pathways include chronic inflammation, mitochondrial dysfunction, microbial translocation, and altered immunometabolic signaling, leading to features such as CD8⁺CD28⁻ T-cell expansion, reduced CD4/CD8 ratios, and impaired vaccine responses. Biomarkers such as iAge, IMM-AGE, and the triglyceride–glucose (TyG) index have emerged as promising tools to quantify immune aging beyond chronological measures. Understanding these interconnected mechanisms offers opportunities for targeted interventions—such as metabolic reprogramming, microbiota modulation, and geroscience-based strategies—aimed at preserving immune resilience and promoting healthy aging in high-risk populations. Full article

The parallel global increase in obesity and Alzheimer’s disease (AD) underscores an urgent public health challenge, with converging evidence indicating that metabolic dysfunction strongly contributes to neurodegeneration. Obesity is now recognized not only as a systemic metabolic condition but also as a modifiable risk factor for AD, acting through mechanisms such as chronic low-grade inflammation, insulin resistance, and adipose tissue dysfunction. Among the molecular mediators at this interface, adipokines have emerged as pivotal regulators linking metabolic imbalance to cognitive decline. Adipokines are hormone-like proteins secreted by adipose tissue, including adiponectin, leptin, and resistin, that regulate metabolism, inflammation and can influence brain function. Resistin, frequently elevated in obesity, promotes neuroinflammation, disrupts insulin signaling, and accelerates β-amyloid (Aβ) deposition and tau pathology. Conversely, adiponectin enhances insulin sensitivity, suppresses oxidative stress, and supports mitochondrial and endothelial function, thereby exerting neuroprotective actions. The imbalance between resistin and adiponectin may shift the central nervous system toward a pro-inflammatory and metabolically compromised state that predisposes to neurodegeneration. Beyond their mechanistic relevance, adipokines hold translational promise as biomarkers for early risk stratification and therapeutic monitoring. Importantly, natural compounds, including polyphenols, alkaloids, and terpenoids, have shown the capacity to modulate adipokine signaling, restore metabolic homeostasis, and attenuate AD-related pathology in preclinical models. This positions adipokines not only as pathogenic mediators but also as therapeutic targets at the intersection of diabetes, obesity, and dementia. By integrating mechanistic, clinical, and pharmacological evidence, this review emphasizes adipokine signaling as a novel axis for intervention and highlights natural compound-based strategies as emerging therapeutic approaches in obesity-associated AD. Beyond nutraceuticals, antidiabetic agents also modulate adipokines and AD-relevant pathways. GLP-1 receptor agonists, metformin, and thiazolidinediones tend to increase adiponectin and reduce inflammatory tone, while SGLT2 and DPP-4 inhibitors exert systemic anti-inflammatory and hemodynamic benefits with emerging but still limited cognitive evidence. Together, these drug classes offer mechanistically grounded strategies to target the adipokine–inflammation–metabolism axis in obesity-associated AD. Full article

Background: Liver regeneration is a complex process involving multiple signaling pathways that coordinate hepatocyte proliferation, survival, and tissue repair. Natural compounds like silymarin, ursolic acid, quercetin, and resveratrol have shown regenerative potential, though their precise molecular mechanisms remain unclear. 6-O-trans-feruloyl catalpol (6FC), a major bioactive compound from Catalpa ovata, exhibits anti-inflammatory and potential antioxidant effects via regulation of NF-κB signaling and redox-sensitive pathways such as Akt and MAPK, which are critical for cell survival and proliferation. Moreover, 6FC exhibits peroxynitrite-scavenging activity, suggesting its potential antioxidant properties that may protect hepatocytes from oxidative damage during regeneration. However, the role of 6FC in liver regeneration has not been elucidated, positioning it as a promising natural therapeutic candidate for hepatic repair. Purpose: This study aimed to determine whether 6FC promotes hepatocyte proliferation and liver regeneration in vivo using a 2/3 PHx mouse model, and to validate its proliferative effects in vitro with HGF-stimulated Hep3B cells. Methods: A 2/3 PHx liver regeneration model was used to evaluate 6FC-mediated liver regeneration. Histological and molecular analyses assessed hepatocyte proliferation and signaling activation. HGF-stimulated Hep3B cells were also used to examine 6FC proliferative effects in vitro. Results: 6FC significantly promoted liver regeneration by restoring the liver-to-body weight ratio and reducing serum ALT and AST levels without inducing excessive immune responses. Mechanistic studies revealed that 6FC activates Akt and MAPK pathways, increases the expression of critical growth factors, and upregulates cell cycle regulators. These effects were also observed in HGF-stimulated Hep3B cells, suggesting that 6FC may enhance hepatocyte proliferation without triggering excessive immune responses. Conclusions: 6FC accelerates hepatocyte proliferation and promotes liver regeneration by activating key redox-sensitive signaling pathways, highlighting its potential as a natural antioxidant-based therapeutic agent. Full article

Adipose tissue renewal requires precise coordination of stem/progenitor cell proliferation, preadipocyte commitment, and terminal adipocyte differentiation. T-cadherin (CDH13), an atypical GPI-anchored cadherin, is expressed in adipose tissue and functions as a receptor for high-molecular-weight (HMW) adiponectin—a key adipokine produced by adipose tissue and involved in metabolic regulation. While T-cadherin is implicated in cardiovascular and metabolic homeostasis, its role in adipogenesis still remains poorly understood. In this study, we used the 3T3-L1 preadipocyte model to investigate the function of T-cadherin in adipocyte differentiation. We analyzed T-cadherin expression dynamics during differentiation and assessed how T-cadherin overexpression or knockdown affects lipid accumulation, expression of adipogenic markers, and key signaling pathways including ERK, PI3K–AKT, AMPK, and mTOR. Our findings demonstrate that T-cadherin acts as a negative regulator of adipogenesis. T-cadherin overexpression ensured a proliferative, undifferentiated cell state, delaying early adipogenic differentiation and suppressing both lipid droplet accumulation and the expression of adipogenic markers. In contrast, T-cadherin downregulation accelerated differentiation, enhanced lipid accumulation, and increased insulin responsiveness, as indicated by PI3K–AKT pathway activation at specific stages of adipogenesis. These results position T-cadherin as a key modulator of adipose tissue plasticity, regulating the balance between progenitor expansion and terminal differentiation, with potential relevance to obesity and metabolic disease. Full article

The rapid evolution of virtual reality systems and the broader metaverse landscape has prompted growing research interest in biometric authentication methods for user verification. These solutions offer an additional layer of access control that surpasses traditional password-based approaches by leveraging unique physiological or behavioral traits. Current literature emphasizes analyzing controller position and orientation data, which presents challenges when using convolutional neural networks (CNNs) with non-continuous Euler angles. The novelty of the presented approach is that it addresses this limitation. We propose a modality transformation approach that generates acceleration and angular velocity signals from trajectory and orientation data. Specifically, our work employs algebraic techniques—including quaternion algebra—to model these dynamic signals. Both the original and transformed data were then used to train various CNN architectures, including Vanilla CNNs, attention-enhanced CNNs, and Multi-Input CNNs. The proposed modification yielded significant performance improvements across all datasets. Specifically, F1-score accuracy increased from 0.80 to 0.82 for the Comos subset, from 0.77 to 0.82 for the Quest subset, and notably from 0.83 to 0.92 for the Vive subset. Full article

In ocean engineering, the demand for fiber-optic vector hydrophones (FOVHs) is increasing. The performance of a FOVH depends on phase consistency between its pressure and acceleration channels, which should match the acoustic field’s properties. Phase polarity, which refers to the alignment of the output signal with the acoustic field direction, is critical. Incorrect phase polarity during sensor assembly can disrupt phase consistency and invalidate directional measurements. This study investigates phase polarity in mandrel FOVHs that use the Phase Generated Carrier (PGC) technique. We develop a theoretical model combining the PGC algorithm with elastic mechanics to analyze the response of acoustic signals. Our model shows that correct demodulated signal polarity requires a specific physical setup: the pressure sensor’s long arm should be on the inner mandrel and the short arm on the outer, while the accelerometer’s positive axis should follow the vector from the long to its short arm. These results are validated through standing wave tube experiments and lake tests. This research provides practical guidelines for the installation and calibration of FOVHs, ensuring phase consistency in underwater acoustic sensing. Full article

Cancer remains a major global health concern, and thus, there is a growing demand for efficient and selective therapies with low systemic toxicity. Natural bioactive compounds have emerged as promising alternatives, and terpenoids have shown notable anticancer properties. They exert antiproliferative, proapoptotic, anti-invasive, and antimetastatic effects through the regulation of multiple molecular targets and signaling pathways, including modulation of apoptosis, suppression of angiogenesis, and inhibition of tumor-promoting inflammation. However, their clinical translation is constrained by poor aqueous solubility, low bioavailability, rapid systemic clearance, and inadequate tumor accumulation. Recent advances in nanotechnology offer strategies to overcome these limitations. Nanocarrier-based systems improve the solubility, stability, and pharmacokinetics of terpenoids, while enabling tumor-targeted delivery and controlled release. Various strategies, such as enhanced permeability and retention effect, ligand-mediated active targeting, and stimuli-responsive release have been used to achieve selective tumor accumulation and improved therapeutic outcomes. The purpose of this review is to provide a comprehensive evaluation of nanoformulated terpenoids in cancer with a special emphasis on their therapeutic applications and mechanisms of action. Preclinical studies demonstrate that nanocarrier-loaded terpenoids significantly increase bioavailability, enhance apoptosis, and suppress tumor angiogenesis compared with free terpenoids. The incorporation of artificial intelligence and machine learning further holds promise for the rational design of nanomedicines, accelerating their path toward clinical translation. Collectively, these developments position nanoformulated terpenoids as a powerful platform in precision oncology with strong potential for future application in cancer therapy. Full article

Despite the acknowledged importance of capital for start-up success, gender disparities persist when trying to raise funds from external sources, including angel investors, venture capitalists, and financial institutions. Many studies have shown that gender stereotypes are harmful and prevent women from gaining access to resources, e.g., capital, distorting their start-up valuations, and influencing the resulting financing decisions. In recent years, gender-specific support measures have emerged that attempt to overcome gender inequalities in early-stage entrepreneurship, including gender-specific accelerator programs. However, there remains a lack of research on the effects of these gender-specific support programs. This study therefore investigates the influence of participating in gender-specific accelerator programs on access to angel capital, as a highly relevant source for the early financing of (women-founded) start-ups, considering signaling theory and its influence by the role congruity theory in an entrepreneurial context. A laboratory experiment involving 227 participants was conducted to explore these dynamics, reflecting perceptions of signals for angel investors. Overall, the findings suggest that gender-specific accelerator programs may positively influence perceived investment decisions by enhancing perceived team competence. Furthermore, investor gender moderates the perception of team competence. The signaling effect that (gender-specific) accelerators have on angel investors does not appear to be as great for men investors as it is for women investors. The findings contribute to signaling theory by understanding the impact of participation in (gender-specific) accelerator programs on the investment decision of angel investors while advocating for more inclusive approaches to fostering diversity and inclusivity within the start-up ecosystem. Full article

Divers’ navigation heavily depends on their experience and physical condition, and accidents caused by failure to return occur every year. To address this issue, we developed a navigation system for divers. This navigation system leverages Raspberry Pi and low-cost sensors, including an accelerometer, gyro sensor, geomagnetic sensor, and pressure gauge, to guide divers along predefined routes back to their starting point. The system employs a 20 Hz sampling frequency and applies high-pass filtering (HPF) to acceleration signals to eliminate gravitational interference. Velocity integration errors are corrected using the rate of pressure change, while impulse noise in accelerometer and geomagnetic sensors is removed via the Robust Kalman Filter (RKF). A time-varying system noise covariance matrix enhances accuracy during rotational states. Quaternion-based attitude avoids gimbal lock, with the Kalman Filter (KF) fusion of accelerometer/geomagnetic data mitigating gyro sensor drift. Forced oscillator trials achieved pitch/roll RMS errors of ±1.23° and ±0.26°. In Kanagawa, Japan, divers successfully navigated 44 waypoints (<5 m spacing) along a route with obstacles (30 m rope, Authors, reefs), with a start/end GNSS positioning error of 6.67 m. Full article

To address the issue of decreased positioning accuracy caused by interference or blockage of GNSS signals in vehicle navigation systems, this paper proposes a GNSS/MEMS IMU array fusion localization method based on an improved grey prediction model. First, a multi-feature fusion GNSS confidence evaluation algorithm is designed to assess the reliability of GNSS data in real time using indicators such as signal strength, satellite visibility, and solution consistency; second, to overcome the limitations of traditional grey prediction models in processing vehicle complex motion data, two key improvements are proposed: (1) a dynamic background value optimization method based on vehicle motion characteristics, which dynamically adjusts the weight coefficients in the background value construction according to vehicle speed, acceleration, and road curvature, enhancing the model’s sensitivity to changes in vehicle motion state; (2) a residual sequence compensation mechanism, which analyzes the variation patterns of historical residual sequences to accurately correct the prediction results, significantly improving the model’s prediction accuracy in nonlinear motion scenarios; finally, an adaptive fusion framework under normal and denied GNSS conditions is constructed, which directly fuses data when GNSS is reliable, and uses the improved grey model prediction results as virtual measurements for fusion during signal denial. Simulation and vehicle experiments verify that: compared to the traditional GM(1,1) model, the proposed method improves prediction accuracy by 31%, 52%, and 45% in straight, turning, and acceleration scenarios, respectively; in a 30-s GNSS denial scenario, the accuracy is improved by over 79% compared to pure INS methods. Full article

Ecology and adaptive differentiation of Epimedium are central to understanding both its taxonomic complexity and medicinal value. In this study, we integrate transcriptomic and plastid data from four natural populations of E. brevicornu (HZ, QLH, TS, WD) to reconstruct their phylogenetic relationships, estimate divergence times, and identify candidate genes associated with local adaptation. Nuclear gene-based phylogenies provide higher resolution and greater topological consistency than plastid data, underscoring the utility of nuclear data in lineages affected by hybridization and incomplete lineage sorting. Molecular dating indicated that major intraspecific divergence occurred during the mid-Quaternary (0.61–0.45 Ma), coinciding with climatic oscillations and montane isolation. Population structure showed strong correlations with temperature and precipitation gradients, suggesting environmentally driven selection. Signatures of positive selection and accelerated evolutionary rates revealed population-specific enrichment of genes involved in stress response, protein modification, signaling, and carbohydrate metabolism—key pathways linked to high-elevation adaptation. Protein–protein interaction networks further indicated a two-tier adaptation mechanism: ancestral network rewiring combined with population co-evolution of interacting genes. Together, these findings advance our understanding of alpine plant adaptation and provide candidate genes for further functional and breeding studies in Epimedium. Full article