Search Results (214)

Background: Bisphenol A (BPA) release from resin-based dental materials is a growing concern due to its potential endocrine-disrupting effects, particularly in pediatric patients. This in vitro study evaluated cumulative BPA release and elution kinetics from commonly used pediatric resin-based materials, due to the limited evidence available. Methods: Three restorative materials (Clearfil Majesty ES-2, Estelite Sigma Quick, and Stela Automix) and one orthodontic material (Transbond XT) were investigated. Eighteen disk-shaped specimens (5.5 mm in diameter and 2 mm in thickness) were prepared for each material and immersed in artificial saliva (pH 6.8) at 37 °C for 1, 7, and 28 days. BPA concentrations were quantified using liquid chromatography–tandem mass spectrometry (LC–MS/MS). BPA release kinetics were evaluated during the early (1–7 days) and late (7–28 days) release phases. Results: All investigated materials released measurable BPA concentrations, with cumulative BPA release progressively increasing up to 28 days. Clearfil Majesty ES-2 and Estelite Sigma Quick exhibited the highest cumulative BPA concentrations, whereas Stela Automix showed markedly lower values. Transbond XT also demonstrated measurable BPA release. For all materials, BPA release kinetics were significantly higher during the early phase than during the late phase (p < 0.001), indicating a non-linear release behavior over time. Conclusions: BPA release from pediatric restorative and orthodontic resin-based materials is material-dependent and characterized by progressive cumulative accumulation associated with significantly higher early-phase release rates. These findings highlight the importance of assessing the safety of resin-based materials used in pediatric dentistry. Full article

Grey cast iron brake discs remain standard in automotive braking systems due to their favourable thermal conductivity and mechanical strength. However, increasingly stringent environmental regulations, including Euro 7, necessitate enhanced surface durability to reduce particulate emissions and mitigate corrosion-related degradation. In this context, laser metal deposition (LMD) offers a promising route to engineer wear-resistant coating systems with tailored microstructures. This study investigates phase formation and microstructural evolution in a 316L/430L-WC multilayer coating deposited on grey cast iron (GJL) brake discs and subjected to brake-shock testing to replicate thermomechanical load cycles representative of real braking conditions. X-ray diffraction (XRD) performed on the interlayer region between the 316L and 430L-WC layers revealed clear evidence of σ-phase formation, indicating intermetallic transformations facilitated by thermal cycling. Microstructural characterization using scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS) identified localized enrichment of Cr- and Fe-rich regions that support the XRD-based interpretation of σ-phase development. These results provide insights into phase transformations and elemental diffusion in LMD-fabricated brake-disc coatings. The findings advance the understanding of thermally induced transformations in multilayer steel systems and support the optimization of LMD coatings for high-temperature and wear-intensive applications through advanced analytical evaluation. Full article

Transit delays can adversely affect passengers, operational efficiency, and daily lives. It is important to develop effective methods to identify and analyze train stations vulnerable to delays. This paper proposes a three-stage analytical framework for analyzing train station delays. In the first stage, the 3-sigma rule defines normal passenger volume ranges and establishes a time window affected by delays. Next, a multivariate time series clustering method identifies stations with stable demand and high volume, considering passenger volume differences both among and within stations. In the final stage, the effects of delays on these key stations are assessed by examining starting, duration, and ending times, and passenger volume variation, providing a comprehensive analysis of delay impact. The proposed framework is illustrated using two real-world incidents: the 2021 delay incident at Longyang Road Station of Shanghai Metro and the 2019 delay incident on the Taoyuan–Luohu section of Shenzhen Metro. Case studies revealed that affected stations are not limited to the specific line or direction of the delay, but also include opposite-direction and transfer stations. Station impacts exhibit phased onset and recovery patterns. Additionally, both increases and decreases in passenger volumes due to the delay present considerable implications. While both incidents exhibit common propagation and recovery patterns, the Shanghai incident displays wider passenger impacts and longer recovery periods, whereas the Shenzhen incident exhibits narrower impacts and faster recovery. Our results will aid transit managers in better managing delays, thereby improving passenger satisfaction and operational efficiency. This paper also offers an integrated station-level analytical framework and initial cross-case empirical evidence, while broader validation remains needed. Full article

Extending the service life of nuclear power plant components beyond their originally designed operational period requires a detailed understanding of the microstructural stability of the materials used. This study focuses on low-temperature precipitation in the austenitic stainless steel 08CH18N10T, which is employed in the main circulation piping of pressurized water reactors. During long-term operation in the temperature range of 100–320 °C, secondary phases such as M₂₃C₆ carbides and intermetallic phase sigma (σ) can precipitate, which can lead to local chromium depletion at grain boundaries, subsequent sensitization of the steel, and susceptibility to intergranular corrosion. The research includes the analysis of samples taken from the decommissioned V1 unit of the Jaslovské Bohunice Nuclear Power Plant, which has been in operation for 28 years. The samples were subjected to thermal aging under laboratory conditions, with an emphasis on evaluating microstructural changes and their impact on corrosion resistance. Based on the experimental results, it can be concluded that the thermal stability of all tested materials is suitable for the operation of the main circulation piping, as the service temperatures to which the main circulation piping is exposed during operation remain below the activation of precipitation that would lead to sensitization and, consequently, susceptibility to intergranular corrosion. Activation of low-temperature precipitation was observed only at 450 °C, while at temperatures up to 400 °C, the structural stability of the material was confirmed, demonstrating its suitability for operation within the specified temperature range of the nuclear power plants’ main circulation piping. Full article

Accurate estimation of vehicle sideslip angle and lateral velocity is essential for the stability control of Advanced Driver Assistance Systems (ADASs). Traditional physics-based observers often exhibit dynamic response distortions under stability-limit conditions due to unmodeled tire relaxation effects, while data-driven methods lack physical interpretability. This paper proposes a Physics-Driven Hybrid Estimation Framework (PD-HEF) to bridge this gap. First, a nonlinear nominal model is constructed as a physical skeleton, and dynamic residual equations are derived to define learning targets. Second, a Spatio-Temporal Feature Coupled Residual Network is designed to capture time-domain phase lag and compensate for spatial nonlinear deviations. Furthermore, a hybrid unscented Kalman filter is developed to inject predicted residuals into the sigma-point evolution. A Dual-Layer Adaptive Mechanism is also introduced to regulate trust weights based on innovation statistics. Joint simulations demonstrate that the proposed framework reduces the root mean square error by over 60% compared to traditional observers while satisfying real-time constraints. Full article

The cigarette beetle, Lasioderma serricorne, is a globally important pest of stored products, and prolonged fumigant use has accelerated resistance development. Glutathione S-transferases (GSTs) are key phase II detoxification enzymes that mediate insect tolerance to xenobiotics. In this study, we identified nine GST genes (LsGSTs) in L. serricorne and classified them into four cytosolic classes, namely epsilon, delta, theta, and sigma, based on phylogenetic analysis. Most LsGSTs were predominantly expressed during larval stages, while LsGSTs7 showed peak expression in adults. Tissue-specific profiling revealed predominant expression in metabolically active organs, including the fat body, Malpighian tubules, and midgut. Inhibition of GST activity using diethyl maleate (DEM) significantly increased larval susceptibility to three emerging fumigants: ethyl formate, benzothiazole, and methyl isothiocyanate. Exposure to LC₃₀ and LC₅₀ concentrations of these fumigants induced up-regulation of multiple LsGSTs, highlighting fumigant-specific detoxification responses. RNA interference targeting nine fumigant-inducible LsGSTs markedly elevated mortality and decreased total GST activity under fumigant stress. Furthermore, recombinant LsGSTs6 protein effectively metabolized methyl isothiocyanate, confirming their direct role in fumigant detoxification. Collectively, these findings provide novel insights into the molecular mechanisms underlying GST-mediated tolerance in L. serricorne and identify specific GST isoenzymes as promising molecular targets for innovative resistance management strategies in stored-product pest control. Full article

With the renewed interest in lunar exploration, evidenced by the increasing number of planned missions over the past decade, space agencies are investing in dedicated lunar communication and navigation systems, such as the European Space Agency’s (ESA) Moonlight Lunar Communication and Navigation System (LCNS), to support various types of missions. Other space agencies, such as NASA and JAXA, are also foreseeing to deploy similar infrastructure, which will all be interoperable according to the LunaNet Specification. One of the critical phases in both human and robotic lunar exploration is the landing of spacecrafts on the Moon’s surface. This operation is complex and challenging, as demonstrated by recent crashes like the Luna25 lander from the Russian Space Agency or the Intuitive Machine private lander. Reliable positioning capabilities during descent are among the various services offered by dedicated lunar navigation systems and shall enable safe and reliable landing to a 90 metres 3-sigma landing accuracy from a target point, as defined by the Global Exploration Roadmap Critical Technology Needs. Faulty landings can be due to several causes. This paper examines the achievable positioning accuracy for a lander targeting the Moon’s South Pole using satellite-based navigation services like Moonlight and how the impact of faulty sensors (such as a faulty IMU) can be mitigated using Moonlight LCNS. Full article

This paper presents an all-digital fractional-N phase-locked loop (ADPLL) operating in the 2.86–3.2 GHz range, optimized for IoT and high-frequency RF transceiver applications demanding stringent phase noise performance, fast settling time, and high integration capability. The key innovation lies in the introduction of a bandpass delta-sigma time-to-digital converter (BPDSTDC) that achieves high-resolution phase detection, an extended detection range of ±2$\pi$, and superior noise-shaping characteristics, completely eliminating the complex calibration procedures typically required in conventional TDC designs. The proposed architecture synergistically combines the BPDSTDC with digital down-conversion blocks to extract phase error at baseband, a divider chain integrated with phase interpolators achieving 1/4 fractional resolution to suppress in-band quantization noise, and a wide-bandwidth digital loop filter (>1 MHz) ensuring fast dynamic response and robust stability. The bandpass delta-sigma modulator is implemented with compact resonator structures and a flash quantizer, achieving an optimal balance among resolution, power consumption, and silicon area. The incorporation of highly linear phase interpolators extends fractional frequency synthesis capability without requiring complex digital-to-time converters (DTCs), significantly reducing design complexity and calibration overhead. Fabricated in a 180-nm CMOS technology, the proposed chip demonstrates robust measured performance. The band-pass delta-sigma TDC achieves a low integrated rms timing noise of 183 fs within a 1-MHz bandwidth. Leveraging this low TDC noise, the complete ADPLL exhibits a measured in-band phase noise of −120 dBc/Hz at a 1-MHz offset for a 3.2-GHz output frequency while operating with a loop bandwidth exceeding 1 MHz. This corresponds to a normalized phase noise of −216 dBc/Hz. The system operates from a 1.8-V supply and consumes 10 mW, achieving competitive performance compared with prior noise-shaping TDC-based all-digital PLLs. Full article

Background/Objectives: Fluvoxamine (FLU) is a selective serotonin reuptake inhibitor and one of the most potent agonists of the sigma-1 receptor. Emerging evidence shows that FLU exerts protective effects in multiple organs, making it a promising candidate for topical ocular therapy. Developing an FLU eyedrop for glaucoma can address a significant treatment gap with potentially fewer side effects compared with conventional therapies. To optimise formulation development, precise quantification of FLU in ocular compartments such as aqueous humour, as well as systemic circulation, is essential to characterise drug absorption, ocular bioavailability, and safety. Methods: We developed and validated a UHPLC-MS method for FLU detection in aqueous humour and serum using simple sample preparation steps. Results: The 11-min-long reverse phase chromatography followed by SRM-based mass spectrometry detection provides a highly selective and sensitive FLU detection method. Our method was proved to be linear in the 0.0625–1.5 µg/mL range and was validated according to the EMA guidelines. Conclusions: The simplicity of sample preparation, the tolerable matrix effects, and the favourable detection parameters provide a robust tool for preclinical pharmacokinetic and pharmacodynamic studies of FLU’s ocular protective effects. Full article

The formation and evolution of secondary phases, such as sigma (σ), chi (χ), Laves, carbides (M₂₃C₆), and nitrides (Cr₂N), have a fundamental impact on the corrosion resistance of stainless steels. These stages alter the matrix’s local chemistry, compromise the passive film’s quality, and promote micro-galvanic interaction, which enhances localized corrosion issues. The thermodynamic stability, precipitation kinetics, and corrosion consequences of secondary phases in austenitic, ferritic, duplex, and lightweight (Fe–Mn–Al–C) stainless-steel systems are thoroughly reviewed and discussed in this paper. Advances in high-resolution characterization techniques, such as TEM, EBSD, atom-probe tomography, and in situ synchrotron techniques, have made it possible to map corrosion problems caused by secondary phases at the nanoscale. Computational thermodynamics (CALPHAD, DICTRA, TC-PRISMA) and emerging machine-learning models now provide quantitative prediction of phase formation and dissolution. Strategies for mitigation through alloy design, thermal treatment, and surface engineering are summarized, together with additive-manufacturing approaches for microstructural tailoring. Finally, this review highlights the integration of multi-scale modeling and sustainable alloy design to ensure phase-stable, corrosion-resistant stainless steels that enhance asset integrity and infrastructure reliability as per Sustainable Development Goals. Full article

Occupational exposure to sharps waste represents a critical challenge for public health systems, directly affecting healthcare workers’ safety, institutional costs, and environmental sustainability. This study aimed to analyze sharps waste management practices and to structure improvement actions for biosafety governance in Brazilian Emergency Care Units (ECUs) through the application of the Lean Six Sigma (LSS) and DMAIC method (Define, Measure, Analyze, Improve, and Control). A single multiple-case study was conducted across three public units in different regions of Brazil, combining direct observation, regulatory checklists based on ANVISA Resolution No. 222/2018 (RDC), and cause–and–effect (5M) analysis. The diagnostic phase identified recurrent nonconformities in labeling, documentation, and internal transport routes, primarily due to managerial and behavioral gaps. Based on these findings, the DMAIC framework supported the development of a low-cost, evidence-based action plan that outlined proposed interventions, including visual checklists, standardized internal routes, and key performance indicators (KPIs), intended to strengthen biosafety traceability and occupational safety. The se proposed actions are expected to support continuous learning, staff engagement, and a culture of shared responsibility for safe practices. Overall, the study provides a structured basis for future implementation and empirical validation of continuous improvement initiatives, aimed at enhancing public health governance and occupational safety in resource-constrained healthcare environments. Full article

This study examines the high-temperature degradation of Hastelloy C276, a corrosion-resistant nickel-based alloy, during exposure to combustion products generated by methane and 99% cracked ammonia. Using a high-pressure optical combustor (HPOC) at 4 bar and exhaust temperatures of 815–860 °C, standard tensile specimens were exposed for five hours to fully developed post-flame exhaust gases, simulating real industrial turbine or burner conditions. The surfaces and subsurface regions of the samples were analysed using scanning electron microscopy (SEM; Zeiss Sigma HD FEG-SEM, Carl Zeiss, Oberkochen, Germany) and energy-dispersive X-ray spectroscopy (EDX; Oxford Instruments X-MaxN detectors, Oxford Instruments, Abingdon, United Kingdom), while mechanical properties were evaluated by tensile testing, and the gas-phase compositions were tracked in detail for each fuel blend. Results show that exposure to methane causes moderate oxidation and some grain boundary carburisation, with localised carbon enrichment detected by high-resolution EDX mapping. In contrast, 99% cracked ammonia resulted in much more aggressive selective oxidation, as evidenced by extensive surface roughening, significant chromium depletion, and higher oxygen incorporation, correlating with increased NO_x in the exhaust gas. Tensile testing reveals that methane exposure causes severe embrittlement (yield strength +41%, elongation −53%) through grain boundary carbide precipitation, while cracked ammonia exposure results in moderate degradation (yield strength +4%, elongation −24%) with fully preserved ultimate tensile strength (870 MPa), despite more aggressive surface oxidation. These counterintuitive findings demonstrate that grain boundary integrity is more critical than surface condition for mechanical reliability. These findings underscore the importance of evaluating material compatibility in low-carbon and hydrogen/ammonia-fuelled combustion systems and establish critical microstructural benchmarks for the anticipated mechanical testing in future work. Full article

Background: This paper presents an analysis and a structured framework for improving inventory accuracy in an automotive factory, considering the current context of global disruptions. In 2023, the company recorded 20,340 inventory adjustments (1695 per month) and a 0.24% monthly net value discrepancy (EUR 256,594 YTD), with a baseline absolute discrepancy of 2.21% of sales. The project aimed to reduce adjustments to below 700 per month and the net value discrepancy to 0.1%. Methods: The research followed the Six Sigma methodology’s Define, Measure, Analyze, Improve and Control (DMAIC) phases, integrating Root Cause Analysis (RCA) and Failure Mode and Effects Analysis (FMEA) to enhance inventory accuracy in manufacturing operations. Results: Implementation significantly improved inventory accuracy: monthly adjustments decreased from 1695 to 971, the highest RPN was reduced from 576 to 144, and the absolute discrepancy-to-sales ratio stabilized at 0.98% (a 56% improvement). Financial variance was reduced to EUR 1948.10 in Q4 2024, while organizational discipline, role clarity and process control also increased. Conclusions: The integrated DMAIC–RCA–FMEA framework proved effective and replicable, enabling systematic identification of root causes, targeted corrective actions and sustainable KPI-driven improvements. The results demonstrate a scalable approach to inventory optimization that supports operational resilience and supply chain performance. Full article

High-nitrogen austenitic stainless steels (HNASS) require compositional strategies that simultaneously maximize corrosion resistance and microstructural stability while suppressing delta (δ) ferrite and deleterious precipitates. Here, an explainable multi-objective design workflow is developed that couples thermodynamic descriptors from the Calculation of Phase Diagrams (CALPHAD) approach—using both equilibrium and Scheil solidification calculations—with machine learning surrogate models, random forest (RF) and Extreme Gradient Boosting (XGBoost), trained on 60,480 compositions in the Fe–C–N–Cr–Mn–Mo–Ni–Si space. The physics-informed feature set comprises phase fractions; transformation and precipitation temperatures for δ-ferrite, chromium nitride (Cr₂N), sigma (σ) phase and M₂₃C₆ carbides; liquidus and solidus temperatures; and the pitting-resistance equivalent number (PREN). The RF model achieves consistently low prediction errors, with a PREN root-mean-square error (RMSE) of ≈0.004, and exhibits strong generalization. Shapley additive explanations (SHAP) reveal metallurgically consistent trends: increasing nitrogen (N) suppresses δ-ferrite and promotes Cr₂N; carbon (C) promotes M₂₃C₆; molybdenum (Mo) promotes the σ-phase; and C and silicon (Si) widen the freezing range. Using the trained surrogate as the objective evaluator, the non-dominated sorting genetic algorithm III (NSGA-III) builds Pareto fronts that minimize the δ-ferrite range, Cr₂N, σ-phase, M₂₃C₆ and the freezing range (ΔT) while maximizing PREN. The Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) is then applied to rank the Pareto-optimal candidates and to select compositions that combine elevated PREN with controlled precipitation windows. This workflow is efficient, reproducible and interpretable and provides actionable composition candidates together with a transferable methodology for data-driven stainless steel design. Full article

Insecticide resistance in insects poses a serious problem in population control of arthropod vectors and spreaders of human and animal diseases. Metabolic resistance to insecticides is facilitated by detoxification system enzymes, including glutathione-S-transferases (GSTs) involved in phase II of xenobiotic biotransformation. The aim of this study was to analyze the glutathione-S-transferase activity and the expression level of different class GST genes in Musca domestica. The test subjects were larvae and 3–5-day-old adults of a laboratory susceptible strain (LabTY) and a field deltamethrin-tolerant population (Nik). Based on the LC50 values, the Nik strain showed sensitivity to chlorpyrifos and chlorfenapyr and tolerance to deltamethrin with a remarkable increase in the level of resistance in males compared to females. Expression analysis of eight GST genes revealed that the expression of the GST-E12 gene (Epsilon class) was significantly elevated and the GST-S1 gene (Sigma class) was significantly decreased in the Nik strain across all groups (larvae, females, and males), with the most pronounced difference in females. A pronounced sexual dimorphism was observed: the expression of most GST genes was significantly higher in males than in females in both strains. For the first time, a consistent male-specific overexpression of multiple GST genes has been demonstrated in M. domestica. Full article