Search Results (16,601)

Saturable absorbers (SAs) are critical for passive mode-locking in ultrafast fiber lasers. Although many materials have been studied as SAs, new candidates with broadband and stable performance are still needed. In this work, we report the synthesis and fabrication of Ti₂O-based SAs and present the first systematic investigation of their performance in broadband ultrafast fiber lasers. Specifically, phase-pure Ti₂O crystals were synthesized via solid-state sintering. High-performance Ti₂O SAs were then fabricated through a photodeposition method. The balanced synchronous twin-detector measurement method demonstrated that Ti₂O exhibited obvious and stable saturable absorption behavior. To validate their broadband mode-locking capability, the as-prepared Ti₂O SAs were integrated into the Yb-doped and Er-doped fiber lasers, respectively. Experimental results show that both laser systems deliver stable pulsed output, with pulse durations of 441.7 ps at 1 μm and 522.5 fs at 1.5 μm. This work pioneers the application of Ti₂O in ultrafast photonics, and provides an important reference and novel research insights for the design and development of advanced broadband optical devices and systems. Full article

Due to fractures in young and mature people, combined with aging and other factors increasing year by year, there is a demand for new materials to efficiently address fracture-healing-related issues. There are designs of new biodegradable Zn-based alloys whose chemical composition provides new opportunities to manufacture medical devices for supporting and assisting bones in their healing processes. To achieve this goal, it is well known that a strength–ductility balance and appropriate degradation are required. In this context, it is vital to know and understand how the addition of elements modifies the as-cast microstructure, which is the basis of further processing steps such as heat treatment and thermomechanical processing. In the present work, a broad characterization was performed of two as-cast hypoperitectic Zn-Ag-based alloys with Mg and Cu additions. First, cooling curves were presented, and a dissertation regarding the temperature appearance of their secondary phases was made. Also, XRD and SEM-EDS techniques were performed, and their mechanical and corrosion performance was analyzed to elucidate which third element is the best option for intended orthopedic applications. Full article

This paper studies a stochastic service system with N-policy, Bernoulli interruption vacations, and a patient server. When the number of waiting customers reaches the threshold N during a vacation, the server interrupts the vacation with probability $p(0\le p\le 1)$, otherwise continuing the vacation until its completion. If the system is empty when a vacation ends, the server waits for a patience period before starting a new vacation. Service station failures occur during service, and interrupted service resumes after repair. We derive the Laplace transform expressions for the transient queue length probabilities and recursive formulas for the stationary queue length distribution. In addition, cost optimization models for the threshold N and the vacation length T are developed, both without and with an average waiting time constraint. Using the Particle Swarm Optimization algorithm, numerical examples under phase-type distributions illustrate how the probability p affects the optimal control policy. Full article

Particle accelerators are complex facilities that collide particles at extreme high speed, aiming to discover new physics. In this context, high-energy calorimeter systems play a crucial role, as they provide the particle energy quantity, which is important information for the potential new discoveries. Therefore, this work evaluates the performance of the commonly used Optimal Filter (OF) method and several Convolutional Neural Network (CNN) architectures in reconstructing the amplitude and phase of simulated signals that represent the response pulses produced by high-energy calorimeters. The comparison is conducted using quantitative metrics—including RMS, MAE, MedAE, and Coefficient of Determination. The results show that different CNN architectures exhibit varying performances depending on the calorimeter cell occupancy rate but generally outperform the typical linear OF method, providing more accurate signal reconstructions. Considering all evaluated occupancy levels (10%, 50%, 80%, and 100%), the CNN-based approaches achieved an average improvement of approximately 79% in amplitude RMS and 62% in amplitude standard deviation when compared to the OF method. For phase estimation, the CNNs achieved improvements of approximately 26% for both RMS and standard deviation metrics. Although the proposed strategy requires a large execution time due to the training process across multiple folds, these findings indicate that CNNs are promising alternatives for calorimeter energy reconstruction, particularly in high-occupancy conditions such as those expected for high-luminosity experiments. Full article

Rhenium (Re) is a critical metal indispensable to high-technology manufacturing, defense, and new energy industries. Molybdenite in porphyry deposits is one of the most important hosts of economically recoverable Re. However, the mechanisms controlling Re enrichment in molybdenite remain debated. Ore-forming fluids in Dabie-type porphyry Mo deposits are CO₂-rich and commonly occur as coexisting vapor and brine phases, favoring phase separation and boiling. Recent work on the Jinduicheng Dabie-type porphyry Mo deposit in the East Qinling–Dabie Mo metallogenic belt suggested that fluid boiling plays an important role in Re enrichment, but whether this mechanism also applies to other Dabie-type porphyry Mo deposits remains unclear. In this study, Mo and S isotopes of molybdenite from the Shapinggou porphyry Mo deposit were employed to investigate Re enrichment in Dabie-type porphyry Mo deposits. The results show that molybdenite contains 1.13–23.56 ppm Re, has δ^98/95Mo values of −0.28‰ to +1.02‰, and shows a negative correlation between δ^98/95Mo and δ³⁴S. From early- to late-stage molybdenite, δ^98/95Mo values decrease systematically. The systematic decrease in Mo isotopic compositions during mineralization indicates that fluid boiling was the key factor controlling their variation. The negative correlation between Re contents and Mo isotopic compositions further suggests that Re enrichment was also controlled by fluid boiling. During boiling, lighter Mo isotopes and Re partitioned into the vapor phase, whereas delayed vapor-phase Re precipitation and increased residual-fluid salinity enhanced Re mobility in the liquid phase, producing late-stage molybdenite with high Re contents and light Mo isotopic compositions. This study demonstrates that fluid boiling was an important process during mineralization at Shapinggou and may represent one of the factors controlling Re contents in Dabie-type porphyry Mo deposits. Full article

This manuscript will present an advancement of transformative research that has been conducted at Oak Ridge National Laboratory (ORNL) over a 25-year period (2000–2025) on a variety of environmental and biological matrices. These investigations derived a fundamental understanding of how elemental detection and analysis of these matrices led to the knowledge and discovery of natural processes in plants and the environment. Each project led to the initiation of a new research area which unearthed awesome and novel breakthroughs. Highlights are listed below: 1. The preliminary research at ORNL centered on the detection of aerosols utilizing Laser-induced Breakdown Spectroscopy (LIBS) technology. The Clean Air Act Amendment (CAAA) of 1990 highlighted the importance of identifying hazardous air pollutants (HAPs) due to their impact on environmental and human health, thereby underscoring the need to detect various toxic elements. Research in aerosol chemistry aimed to identify these harmful elements released by factories during periods of increased emissions in their manufacturing processes. LIBS emerged as the most effective method for real-time, in situ measurements of metal species in both gaseous and aerosol phases. 2. An understanding of the presence of total carbon in soils gives perspective on how to develop carbon sequestration strategies. The recognition that carbon sinks can evolve back to carbon sources to emit back to the atmosphere was an important consideration. Also, the concentration of carbon in soil indicates the health of land areas for growing crops successfully. 3. The direct detection of most of the elements in a wood sample in a single emission spectrum, without sample preparation, encouraged the research to use the LIBS technique for preservative treated wood coupled with use of multivariate statistical methodology. Additionally, it encouraged the researchers to try to differentiate natural woods from different parts of the country, and it was successfully demonstrated that LIBS coupled with MVA analysis could differentiate wood of different species from each other and of similar species grown in different environments based on their elemental spectra. This was a breakthrough since it revealed a systematic approach to connect elemental scarcity and abundance to either drought or typical rainfall conditions for the hardwood trees grown in specific areas. 4. Furthermore, the research progressed to reveal physiological and developmental processes contributing to biomass production such that the variation in leaf elemental composition increases our understanding of terrestrial nutrient cycles, as well as tracking the transfer of toxic elements from soils to living organisms. 5. Recently another breakthrough viz., ionomics initiated the correlation of elements to specific genes, uncovering the function that the element performed in the plant. More recently, this has been extended from plants to fungi as well as fungi growing in symbiotic relations with plants. Full article

Dopamine dysregulation is connected to several neurological disorders, including Parkinson’s disease, Huntington’s disease, and addiction. A new, precise, accurate, and specific reversed-phase high-performance liquid chromatographic method was developed for dopamine determination in different biological media (human/mouse plasma and mouse brain homogenate). The chromatographic assay was performed using Avantor ACE^® RP-18 (250 × 4.6 mm, 5 µm) column equipped with a suitable ODS pre-column. The temperature was ambient, and the mobile phase was composed of 10 mM potassium dihydrogen phosphate buffer (pH = 3) with 0.25 g/L sodium octanesulfonate, methanol, and acetonitrile at a volume-to-volume ratio of 75:20:5. Isocratic elution mode, flow rate 1.0 mL/min, and ultraviolet detection (280 nm) were applied. The procedure was validated for linearity, and all calibration curves were linear over the selected range with determination coefficients greater than 0.998. Intraday repeatability, expressed as the coefficient of variation, did not exceed 4.88% for the plasma and 3.32% for the mouse brain homogenate samples across all tested concentration levels. The proposed chromatographic method was evaluated in terms of greenness, whiteness, and blueness using three ecological metrics (the Analytical Greenness software, White Analytical Chemistry model, and Blue Applicability Grade Index). The optimized procedure was proven to be suitable for implementation in the routine analytical practice. Full article

As one of the core technologies of predictive maintenance, the development of remaining useful life (RUL) prediction is gradually transitioning from early single-mechanism modeling to a new phase characterized by the deep integration of physics-based approaches, data-driven methods, and uncertainty awareness. This paper first analyzes the fundamental challenges facing this development, such as multi-stress coupling, sensor degradation, and non-stationary noise. By comparing the core advantages and applicability boundaries of statistical models, data-driven models, and hybrid models, it constructs a capability map for RUL prediction. It further points out that current RUL prediction still faces critical capability gaps in areas such as physical consistency and uncertainty decoupling. Finally, the paper distills a new paradigm for engineering implementation, including mechanism-guided neural architecture design and digital twin-driven online parameter adaptation. The research indicates that future RUL prediction studies must transcend the competition over accuracy metrics and shift toward the coordinated development of robustness, interpretability, and decision adaptability—a trinity guided by the principles of “trustworthy AI.” Full article

Despite their high effectiveness in reducing material flammability, modern brominated flame retardants (BFRs) remain poorly understood with respect to the toxic substances they generate during combustion. BFRs such as 1,2-bis(pentabromodiphenyl)ethane (DBDPE) and tetrabromophthalate diol (PHT4-DIOL) have been introduced following the limitations on legacy brominated additives. However, their thermal decomposition pathways and toxic product emission profiles under real fire conditions remain poorly characterized. Exposure to elevated temperatures may promote the formation of halogenated toxicants and environmentally persistent compounds, raising concerns that extend beyond conventional fire-safety performance. The combustion behavior of DBDPE-, PHT4-DIOL-, and BFR-containing epoxy resins was investigated using a steady-state tube furnace designed to reproduce realistic fire scenarios. Controlled temperature and ventilation conditions were applied to simulate representative stages of fire. Combustion emissions were comprehensively characterized using Fourier transform infrared spectroscopy (FT-IR) to analyze asphyxiant and irritant gases and solid-phase microextraction gas chromatography–mass spectrometry (SPME-GC-MS) for volatile and semi-volatile organic compounds. The results presented that the incorporation of BFRs substantially altered combustion emission profiles, promoting the formation of brominated and mixed-halogenated species alongside toxic gaseous products. Significant differences in the composition and distribution of combustion byproducts were observed between non-modified and BFR-containing materials, indicating that the environmental and toxicological consequences of these additives cannot be adequately assessed solely through flammability-reduction metrics. These conclusions provide new knowledge of the environmental impacts of brominated flame retardants and highlight the importance of integrated fire-safety assessment strategies that simultaneously consider flame-inhibition efficiency, combustion toxicity, and environmental persistence. Full article

Despite significant improvement in long-term survival with the advent of immunotherapy, a substantial proportion of lung cancer patients develop primary and acquired resistance. Among emerging strategies to overcome this challenge, cancer vaccines represent a promising approach, especially for non-small-cell lung cancer (NSCLC). A variety of vaccine platforms have been investigated, including nucleic acid-based vaccines, peptide vaccines, dendritic cell vaccines, and viral vector-based approaches. To date, cancer vaccines have not demonstrated consistent survival benefit in large randomized trials, and their clinical application remains limited. Challenges include high production costs, complexity in manufacturing, and issues related to drug stability and scalability. However, several ongoing early-phase trials show promising signals for several platforms, as new tools and technology become available to optimize neoantigen selection, vaccine production, efficacy, and safety. In this review, we summarize the current evidence of vaccines in NSCLC treatment across different stages and therapeutic settings. Full article

Snakeflies (Raphidioptera) are generally assumed to have the most gradual (and plesiomorphic) type of holometabolous metamorphosis, often including saproxylic larvae. Herein we investigate the diversity of snakeflies over time. We explore morphological details that have rarely been in focus of scientific studies such as the clavate organs of the legs. In total, 165 new immature snakefly specimens, mostly from 100 million-year-old (Cretaceous) Kachin amber, are reported. Combined with data from the literature, we assembled a dataset of 550 specimens, including immatures and adults from Cretaceous (over 200 immatures) and Eocene amber and from the extant fauna. From these, we extracted shape data of different body regions—ten subsets in total with over 2500 analysed shapes. Our analysis supports earlier observations (based on relative lengths) that snakefly larvae were much more diverse in their morphology in the past compared to their modern representatives. Furthermore, we recognise a strong morphological separation of modern larvae and adults (with pupae being intermediate), while in fossils the overlap of representatives of both life phases is quite strong. This supports earlier qualitative observations that the ontogeny of Cretaceous snakeflies was even more gradual (and likely plesiomorphic for Raphidioptera and presumably Holometabola) than in extant snakeflies. The analyses revealed that some Cretaceous and Eocene snakeflies had a slender head and prothorax morphology that is absent nowadays. This supports a difference between the modern and Eocene fauna. Additionally, a gap analysis was performed for the best-sampled subsets to explore morphological constraints in snakefly morphology. Full article

To investigate the rutting resistance of Large Stone Asphalt Mixture (nominal maximum aggregate size of 53 mm, abbreviated as LSAM-50), this study evaluated the effects of temperature, load, and their interaction on the rutting performance of LSAM-50 through large-thickness rutting tests. It analyzed the characteristics of rutting deformation under varying thermal and loading conditions, established a permanent deformation-temperature-load dependency model, and explored the correlations between permanent deformation and high-temperature evaluation indicators. The findings indicate that the temperature-load interaction fundamentally alters the load-transfer mechanism between the viscoelastic matrix and coarse aggregates within LSAM-50, thereby activating the interlocking effect of its thick structural skeleton. The dynamic stability undergoes a pronounced reduction as temperature or load increases, peaking at a degradation rate of 40–57% within the 40–50 °C interval. Furthermore, the rutting deformation of the LSAM-50 mixture demonstrates significant temperature and load dependency; as the number of loading cycles increases, the deformation exhibits an initial rapid escalation before reaching a plateau. During temperature elevation and load escalation, the rutting deformation increases in a step-wise manner. Notably, the preliminary application of low temperatures and light loads imparts a substantial “training” effect on the material’s rutting resistance. Once the mixture is wheel-tracked to densification under high temperatures or heavy loads, negligible new deformation is generated during the subsequent cooling or unloading phases. Specifically, upon the initial unloading from 1.1 MPa to 0.9 MPa, the incremental deformation is merely 0.04 mm; upon further unloading to 0.7 MPa, the additional deformation approaches 0 mm. The established permanent deformation-temperature-load dependency model for LSAM-50 yields a high predictive correlation of 96%. Moreover, the permanent deformation exhibits robust linear relationships with 1-h rutting depth (R² = 0.95), compressive strength (R² = 0.91), and shear strength (R² = 0.97). These indicators can thus facilitate the rapid and precise estimation of permanent pavement deformation. Full article

Advances in fetal diagnosis and molecular medicine have opened new opportunities for in utero molecular-targeted drug therapy, shifting fetal treatment from purely procedural interventions toward pharmacologic strategies that address disease mechanisms before irreversible organ damage occurs. In this review, we highlight recent advances in in utero drug therapy, focusing on molecular-targeted approaches with emerging clinical or trial-level evidence. Early clinical experience and ongoing trials have demonstrated the feasibility of achieving therapeutically relevant fetal drug exposure, although the strength of evidence varies considerably across therapeutic classes. However, significant challenges remain, including optimization of fetal drug delivery, characterization of fetal pharmacokinetics and pharmacodynamics, long-term safety assessment, and ethical considerations. The current evidence base ranges from single case reports to ongoing Phase 3 clinical trials, underscoring both the promise of prenatal molecular therapeutics and the need for further prospective evaluation. Continued integration of fetal imaging, genomics, ethics and pharmacology will be essential to advance safe and effective prenatal precision therapies. Full article

We present a theoretical study focused on the photoelectron spectrum of near-infrared (NIR) laser-driven ionization of hydrogen atoms by attosecond pulse trains composed of several HHs of the former. We analyze the effects of increasing the intensity of the NIR probe laser to account for the interference of multiple quantum pathways arising from mainbands formed in ionization by the attosecond pulse train within the strong-field approximation (SFA) beyond the commonly used first-order perturbative (in the NIR laser intensity) reconstruction of attosecond beating by interference of two-photon transitions (RABBIT). The structure of the energy bands formed in the photoelectron spectrum is governed by quantum interferences of the photoelectron wave packet released within one optical cycle of the NIR probe laser field—intracycle interference—and by the number of active high harmonic components, leading to higher-order Fourier contributions as a function of the NIR–XUV relative phase delay. We show that Fourier terms can be interpreted in terms of well-defined semiclassical trajectories. Our results demonstrate a significant departure from the standard two-path quantum-interference RABBIT picture, showing that both the phase-dependent oscillations of mainbands and sidebands and the extracted phase delays depend strongly on the probing laser intensity. The predictions of the SFA reveal that the above-threshold ionization bands exhibit systematic splitting and oscillation patterns as a function of the NIR intensity. SFA predictions are compared with results obtained within ab initio solutions of the time-dependent Schrödinger equation (TDSE), showing an excellent agreement, which evidences the minor effect of the Coulomb potential of the remaining ion on the escaping photoelectron for high energy above-threshold ionization. The precise study of the SFA reference phases is essential for the determination of the effect of the Coulomb potential on the escaping photoelectron for what these findings provide new insights into attosecond chronoscopy in the strong-field regime. Full article

Advanced Metering Infrastructure (AMI) over 5G New Radio (NR) massive machine-type communication (mMTC) networks require efficient and adaptive communication mechanisms to support reliable data delivery for large numbers of smart meters under dynamic traffic and channel conditions. In this work, we propose a framework in which each smart meter chooses, at runtime, whether to transmit directly to the base station (BS) or via a nearby Data Aggregation Point (DAP). The optimal choice is dynamic and depends on DAP buffer occupancy, periodic congestion, channel quality, and packet deadline pressure. Formulating this as a per-meter binary decision yields an action space of size $2^N$ for N meters, which is intractable for reinforcement learning (RL). We reformulate the problem as regional strategy composition: the RL agent selects one parameterized association strategy for each DAP region from a small library of interpretable rules, and a deterministic mapping expands the regional choice into per-meter modes. It reduces the policy action space from $2^N$ to $K^D$, where D is the number of DAPs and K the number of strategies, while preserving meter-level control granularity. We evaluate Proximal Policy Optimization (PPO) and Deep Q-Network (DQN) controllers against eight meter-level baselines on a 5G NR-calibrated simulator with 1500 m, six DAPs, deadline-bounded delivery, stale channel-state information, and phase-offset congestion cycles. Across three traffic regimes and five random seeds, PPO improves packet delivery ratio (PDR) over the strongest heuristic by +0.63, +2.41, and +2.66 percentage points under baseline, high-load, and bursty-cycle conditions, respectively; all gains are statistically significant (paired t-test, $p<0.001$; Cohen’s d up to 5.12), and the advantage grows with traffic stress. The results show that learned regional composition of classical heuristics outperforms any single fixed heuristic precisely when no individual rule is globally optimal. Full article