Search Results (2,397)

Background/Objectives: Prepubertal localized aggressive periodontitis/LPP is an extremely rare but extremely fast-progressing form of periodontal disease involving systemically healthy children, starting in primary and mixed dentition. Our aim is to synthesize the data (January 2014–April 2026) on LPP progression description in systemically healthy children aged 2–13 years; clinical and biological responses to available treatment strategies, focusing on disease progression pattern, treatment efficacy and factors influencing treatment outcomes; and correlating findings with a report of a 24-month follow-up of a female prepubertal Caucasian patient during the primary and early stages of mixed dentition. Methods: A total of 489 studies were found after deduplication for the selected period. Due to the eligibility criteria, 9 studies plus another 10 contextual publications were included. Additionally, a 24-month follow-up of a previous LPP case was correlated. Results: LPP displayed rapid tissular destruction in primary dentition with risks to transfers to mixed and permanent dentition. The systemic antibiotic treatment reduced tissue loss, enabling fast periodontal regeneration. LPP is rare but severe, with a continuous biological trajectory, and with the window of opportunity remaining when the first symptoms appear. A few months (4–6 months) delay in diagnosis leads to irreversible tooth loss even in young patients with high biological healing potential. Conclusions: Systemic antibiotic treatment is mandatory in LPP/C-MIP cases from the primary dentition phase but does not reset host susceptibility. The Amoxicillin/Augmentin–Metronidazole association is recommended, with caution regarding dosage (adverse reactions). Periodontal gains are radiologically and clinically proven, but rebounding is possible. Full article

This paper presents a comprehensive numerical investigation into the transient thermo-structural response of axial bellows during start-up and shutdown cycles in long-distance heating pipelines. Using ANSYS-based transient thermal–structural coupling finite element analysis under the pure linear elasticity and constant internal pressure, the spatio-temporal evolution mechanisms of temperature fields, axial deformation, and equivalent stress are systematically analyzed. The results demonstrate the highly synchronized evolution between temperature and deformation fields, with maximum axial deformation and equivalent stress consistently concentrated at the convolution root and transition arcs. Under steady-state high-temperature conditions (130 °C), the maximum equivalent stress reaches 332.78 MPa. However, after complete cooling and unloading, minimal residual deformation (≤0.001 mm) and residual stress (8.86 MPa) are observed, satisfying the pressure vessel shakedown criteria and confirming the inherent self-limiting nature of thermal secondary stresses. A specific decoupling phenomenon is revealed during the high-temperature steady-state holding period, where the deformation stabilizes while the stress undergoes secondary redistribution. The comparative analysis of different temperature change rates indicates that the fast start-up/shutdown (0.55 °C/s) induces severe transient temperature gradients, causing a nearly 50% increase in the maximum equivalent stress compared to the slow start-up/shutdown (0.275 °C/s). This study provides theoretical foundations for the service safety assessment of axial bellows and recommends gradual heating/cooling operation strategies (≤0.3 °C/s) to mitigate structural thermal shock risks. Full article

With the digital economy advancing at a fast pace, digital transformation plays a pivotal role in reinforcing firms’ innovation capability and promoting high-quality development. This study analyzes Chinese non-financial publicly listed firms on the A-share market over the period 2009–2023. Based on text mining of annual reports, this study constructs an index capturing digital transformation and empirically evaluate its impact on innovation output with firm and year fixed effects. The estimates suggest that digital transformation meaningfully increases firms’ innovation output; the inference is unchanged when applying instrumental-variable approaches and conducting extensive robustness checks. Mechanism analysis reveals two parallel channels: (1) the R&D investment mechanism, characterized by improvements in R&D intensity, capitalization rate, per capita efficiency, and investment growth; (2) the governance environment mechanism, reflected in enhanced internal control, improved information disclosure quality, and strengthened audit supervision. Once firms are stratified by characteristics, the estimated positive effect of digital transformation is most pronounced for firms with low financial constraints, large size, eastern locations, and state ownership. This study identifies both direct and indirect mechanisms linking digital transformation to innovation and highlights how firm- and region-specific features condition the magnitude of this effect, thereby offering empirical implications for corporate digitalization strategies and policy design. Full article

Background: L-tyrosine, classified as a dispensable amino acid, is widely consumed as a component of commonly consumed foods and as a dietary supplement. However, 4-week safety data on supplementation with this amino acid remain limited. Methods: The aim of this study was to evaluate the safety and tolerability of L-tyrosine supplementation over a 4-week period and to estimate the no-observed-adverse-effect level (NOAEL). In a randomized, double-blind, placebo-controlled crossover trial, 30 healthy adult men received L-tyrosine at graded daily doses (0, 1, 2, 3, or 4 g/day). Each participant received four of the five doses in a randomized sequence, with each intervention period separated by a 2-week washout period. The primary endpoints were clinical laboratory parameters, and the secondary endpoint was the incidence of adverse events. Anthropometric and dietary parameters were also assessed. In addition, plasma amino acid concentrations following L-tyrosine supplementation were evaluated as exploratory outcomes. Results: No clinically meaningful or statistically significant dose-related abnormalities were observed in hematological, biochemical, or electrolyte parameters at any dose. Anthropometric and dietary parameters remained unchanged. No serious adverse events occurred, and the incidence of mild-to-moderate adverse events was comparable to that observed with placebo. At the end of each supplementation period and under fasting conditions, plasma L-tyrosine concentrations modestly increased at the highest dose (4 g/day), whereas concentrations of other amino acids remained unchanged. Conclusions: Four-week supplementation with L-tyrosine at doses up to 4 g/day was well tolerated in healthy adult men and was not associated with biochemical and clinically relevant adverse effects under the conditions of this study. These findings suggest that 4 g/day represents the highest tested intake level without observable adverse effects and may serve as the NOAEL under the present 4-week study conditions. Full article

In modern radar and electronic countermeasure systems, frequency-agile (FA) signal generators with low phase noise are of vital importance. The optoelectronic oscillator (OEO) is restricted by the periodic boundary condition (PBC), despite its superior performance in phase noise and frequency tunability. This paper proposes a new FA optoelectronic hybrid oscillator scheme, which employs a reconfigurable aperiodic FA filter and a dynamic frequency compensation module to collaboratively break the PBC limitation. It achieves fast switching and fine-grained frequency hopping at the 100 kHz level while maintaining low phase noise. Theoretical and experimental verification show that the system can generate arbitrary FA radio frequency (RF) signals from 1.95 GHz to 2.05 GHz with a tuning range of 10³ times the free spectral range (FSR), and the phase noise reaches −120 dBc/Hz at 10 kHz offset. This study provides a novel technical route for generating narrow-step frequency-agile signals and effectively improves target detection accuracy and anti-jamming performance in electronic warfare applications. Full article

The circadian clock is closely linked to glucose regulation, but the dynamical consequences of specific metabolic feedback pathways on core clock regulation remain incompletely understood. In this study, we developed a theoretical metabolic-circadian model incorporating a REV-ERB$\mathrm{\alpha }$-glucagon-glucose feedback pathway. The model extends a previously established mammalian circadian clock framework by introducing glucagon-mediated regulation of blood glucose and glucose-dependent modulation of Rev-erbα transcription. Using this model, we examined how the feedback pathway affects circadian oscillations, the sensitivity of period and amplitude to parameter perturbations, and phase-related responses under light stimulation and light–dark cycles. Simulations of the feedback-related parameters showed that the glucose-to-clock feedback strength had a marked effect on oscillation period and amplitude, motivating a further assessment of whether regular circadian dynamics were preserved under parameter perturbations. We therefore analyzed both one-parameter perturbations and simultaneous perturbations of all model parameters. For one-parameter scans, we quantified not only the oscillatory boundaries but also the period variation and the amplitude variation of Per and Rev-erbα within the oscillatory ranges. For simultaneous all-parameter perturbations, Latin hypercube sampling was used to compare coupled and uncoupled models under bounded perturbation ranges. The coupled model showed a higher fraction of regular circadian oscillations under local perturbations, mainly by reducing the probability of rhythm loss. We further examined phase responses and light–dark entrainment to assess how the feedback affects dynamical properties beyond period and amplitude. In the phase-response analysis, the feedback reduced excessive phase shifts in the model, suggesting a possible phase-response robustness effect in this theoretical framework. These theoretical results suggest that the REV-ERB$\mathrm{\alpha }$-glucagon-glucose feedback pathway may be relevant to circadian regulation under fasting-associated metabolic conditions. Full article

Accurate electricity price forecasting (EPF) is essential for market participants to optimize trading strategies and for power systems to accommodate the increasing penetration of volatile renewable energy sources. However, electricity price series are characterized by strong nonlinearity, high volatility, and significant structural breaks, which pose substantial challenges to conventional forecasting models. Although numerous hybrid deep learning models have been proposed for EPF, most existing approaches either overlook structural breaks or treat them as outliers rather than as signals of regime shifts, often resulting in systematic forecasting degradation when market conditions change abruptly. To address this issue, this study proposes COCAL-TTL, a novel multi-stage structural break-aware forecasting framework that integrates regime-adaptive data partitioning with a functionally differentiated hybrid deep learning architecture. First, a joint detection scheme combining the Iterated Cumulative Sum of Squares (ICSS) algorithm and the Chow test is employed to partition Spanish electricity market data from 2014 to 2023 into distinct regimes. Within each regime, CEEMDAN is applied to extract multi-scale features, which are subsequently reconstructed into trend, periodic, and random components based on an independent sample t-test and Fast Fourier Transform (FFT). The CNN-SE Attention-LSTM (CAL) model, with hyperparameters optimized by the Osprey Optimization Algorithm (OOA), serves as the primary forecasting engine. In addition, a dedicated heterogeneous error correction module, namely TTL, is introduced, in which Temporal Convolutional Network, Transformer, and LSTM are designed to capture local transients, long-range dependencies, and transitional dynamics in the residual series, respectively. Empirical results demonstrate that compared with the Naive benchmark, COCAL-TTL achieves percentage MAPE improvements of 58.48% and 48.97% in low- and high-volatility regimes, respectively. These findings indicate that the proposed structural break-aware framework provides a robust data-driven solution for EPF under heterogeneous market conditions and offers technical support for stable electricity market operation in the context of renewable energy integration. Full article

Background: The increasing prevalence of overweight and obesity highlights the need for practical and sustainable dietary strategies for weight management. Although dietary fibre intake is associated with improved satiety and metabolic health, achieving recommended intake levels through whole foods alone remains challenging. Evidence supporting convenient, ready-to-consume fibre beverages in free-living overweight adults is also limited. Therefore, this study evaluated the effects of a soya-based dietary fibre beverage (SBB) on body composition and metabolic parameters in overweight adults. Methods: A 12-week parallel, cluster-randomized controlled trial was conducted on overweight university students and staff. An intervention group (IG) (n = 21) consumed the soya-based dietary fibre twice daily for 12 weeks, while the control group (CG) (n = 21) continued their habitual diet. Results: Significant group × time interactions were observed for body weight (p < 0.001), BMI (p = 0.021), waist circumference (p = 0.046), waist-to-hip ratio (p = 0.042), and body fat percentage (p = 0.004). The IG showed reductions in body weight (−1.12 kg), waist circumference (−4.29 cm), and body fat percentage (−0.73%), whereas the CG demonstrated minimal changes. No significant changes were observed in fasting glucose, lipid profile, CRP, or IL-6, suggesting no clinically significant adverse biochemical changes during the intervention period and supporting its short-term tolerability. Dietary analysis confirmed a marked increase in fibre intake in the IG (~50 g/day), indicating good adherence to the intervention. Conclusions: SBB supplementation improved body composition and central adiposity without affecting systemic inflammatory biomarkers and may represent a practical dietary approach for weight management in free-living overweight adults. Further studies are needed to confirm its long-term efficacy and safety. Full article

Introduction: Populations of freshwater fish species of the Iberian Peninsula have been declining since the mid-20th century, and several types of actions (from in situ to ex situ actions) have been applied over the past decades. However, limited knowledge about their reproductive biology makes it necessary to investigate different aspects of the reproductive cycle for improving breeding programs. Objective: The main objective of this work was to advance knowledge in the sperm biology of two endemic fish from Portugal rivers, trying to check whether breeding in captivity is a factor able to modulate sperm subpopulations. Methodology: Populations of different endangered leuciscid species (Iberochondrostoma lusitanicum, IL, and Achondrostoma occidentale, AO) were sampled during the spring of 2022 both in captive populations kept at Aquário Vasco da Gama (AVG) and in wild populations (WILD) from different Portuguese rivers. Sperm samples were collected, and sperm motion parameters were assessed by using a CASA system (VSL, VAP, STR, LIN, WOB, ALH and BCF). Results: The application of a two-step cluster analysis yielded four sperm subpopulations (SP1, SP2, SP3 and SP4) in both species. SP1 comprised fast, linear spermatozoa (high VCL, LIN, STR). SP2 contained slow linear cells (low VCL, high LIN, STR). SP3 included fast nonlinear spermatozoa (high VCL, low LIN, STR). SP4 represented slow nonlinear cells, with low values for all three kinematic parameters. Regarding the origin of fish (wild and captive), and for both species, WILD leuciscids showed higher values of linear and fast sperm subpopulation (SP1) than captive fish (AVG), which showed a higher percentage of non-linear subpopulations (SP3 and SP4). Conclusions: In this context, and given that fast and linear spermatozoa (SP1) have traditionally been correlated with high fertilization success in many fish species, these results may indicate that breeding in captivity over a long period of time may affect gamete quality, making it necessary to renew the broodstock from time to time to avoid reproductive problems (i.e., loss of sperm quality and cases of inbreeding). Full article

Fast, convergent local-mode expansions of nonlinear water waves are discussed for the representation of the velocity and stream function. Subsequently, the representations are used to derive and study a novel nonlinear coupled-mode system of differential equations on the horizontal plane, with respect to unknown horizontal velocity modal amplitudes and free-surface elevation. The coupled-mode system, in conjunction with the convergence properties of the local-mode series, facilitates the numerical solution of the water wave propagation problem over general bottom topography. The efficiency of the present method is demonstrated through various examples, including the simulation of periodic waves in a constant depth and over trapezoidal bar test cases. The results show the robustness and accuracy of the coupled-mode system in capturing the complexities of wave transformations over non-uniform bathymetric features. Moreover, truncating the modal expansions of the wave velocity field by keeping only the first mode leads to a low-cost, single-mode nonlinear wave model with enhanced dispersion characteristics that is useful for engineering applications. Full article

Most detraining research in swimming has focused on competitive athletes, whereas less is known about recreational university swimmers, a population commonly exposed to temporary interruptions in structured training. This study examined the effects of 4 weeks of naturally occurring detraining on anthropometric, body composition, biochemical, kinematic, and performance variables in recreational university swimmers. Sixteen young swimmers were assessed before and after detraining, following at least one year of participation in a structured university swimming training program. Anthropometric, body composition, biochemical, kinematic, and performance variables were assessed before and after the detraining period. After detraining, waist and hip circumferences, fat mass, and total cholesterol increased. In contrast, fasting glucose, triglycerides, post-exercise lactate, 50 m performance, and kinematic variables showed no statistically significant changes. These findings suggest that, in recreational university swimmers, anthropometric, body composition, and metabolic variables may be more sensitive to short-term detraining than sprint performance-related outcomes. However, the absence of statistically significant performance changes should be interpreted with caution. Full article

Background: Post-COVID syndrome represents a significant medical and public health challenge, particularly among older adults and individuals with type 2 diabetes mellitus (T2DM), in whom disturbances in immune and metabolic homeostasis may contribute to the development and persistence of symptoms following SARS-CoV-2 infection. Objective: To investigate the clinical, immunological, and metabolic characteristics of post-COVID syndrome in older adults with T2DM. Methods: A cross-sectional comparative study was conducted involving 141 patients aged ≥ 60 years who were evaluated more than one year after SARS-CoV-2 infection. Clinical data, anthropometric measurements, complete blood count parameters, biochemical markers, glycated hemoglobin (HbA1c), and SARS-CoV-2-specific IgG antibodies were assessed. Statistical analyses were performed using nonparametric methods, while Pearson’s χ² test was applied for categorical variables. A p-value < 0.05 was considered statistically significant. Results: Symptoms consistent with post-COVID syndrome one year after SARS-CoV-2 infection were identified in 53.2% of participants. No significant differences in anthropometric characteristics, hematological parameters, or most biochemical markers were observed between patients with and without post-COVID syndrome. Patients with T2DM exhibited higher fasting glucose, HbA1c, and SARS-CoV-2–specific IgG antibody levels, reflecting underlying metabolic characteristics and differences in humoral immune responses during the late post-COVID period. Conclusions: Post-COVID syndrome symptoms were frequently observed among older adults at the time of assessment, more than one year after SARS-CoV-2 infection, despite normalization of most laboratory parameters. In patients with T2DM, higher glucose, HbA1c, and antibody levels likely reflect underlying metabolic characteristics rather than a direct effect of post-COVID syndrome. Further longitudinal studies are warranted to clarify the long-term clinical significance of the observed metabolic and immunological findings. Full article

Ultra-High Molecular Weight Polyethylene (UHMWPE), the standard base material in ski manufacturing, offers excellent gliding performance but exhibits limited mechanical and scratch resistance on hard and icy snow conditions. In this work, stainless steel is proposed as a mechanically robust alternative, and its inherently higher friction against snow is addressed through surface engineering. The snow friction behavior of 301H stainless steel surfaces decorated with fishbone-like microstructures combined with Laser-Induced Periodic Surface Structures (LIPSSs) was investigated using a custom-built snow tribometer. Several pattern designs, with different pitch distances and depths, were engraved using femtosecond laser pulse irradiation. We conducted morphological, physical, and chemical investigations through microscopy, static contact angle measurements, and X-ray Photoelectron Spectroscopy analyses. Results indicate that the gliding performance is not directly related to the modifications in surface chemistry and wetting behavior of the samples but is affected by the geometry and orientation with respect to the sliding direction of the specific micro- and nano-features. Overall, we achieved friction coefficient values comparable to those found in UHMWPE with a fast and economically sustainable single-step laser-texturing process. This approach allows the industrial up-scaling of the fishbone-texture design to real-size alpine ski prototypes. Full article

The growing use of wireless technology significantly increases the exposure of all living organisms to radiofrequency electromagnetic fields (RF-EMF). However, the physiological effects of RF-EMF on plants have not yet been sufficiently researched. In this study, we investigated the effects of RF-EMF radiation in the frequency ranges 1890–1900 MHz (DECT) and 2.4 GHz plus 5 GHz (Wi-Fi) on photosynthetic performance of Tilia plants (Tilia tomentosa). The recorded fast chlorophyll fluorescence transients were used to analyze the structure and function of PSII by the JIP-test. The analysis of the fluorescence of chlorophyll a showed that the RF-EMF interfered with the electron transport processes of photosynthesis. Tilia plants exposed to RF-EMF induced decrease in photosynthetic efficiency (F_V/F_M) and inactivation of part of PSII reaction centers (RC/CS_O). Observations of leaf senescence and lifespan over a period of 102 days showed that RF-EMF-exposed Tilia plants exhibited accelerated aging. Full article

In single-phase PWM rectifiers, due to the inherent time-varying characteristics of the source voltage and current as well as the periodic operation of the converter bridge, the instantaneous input power on the AC side inevitably exhibits a twice-fundamental-frequency pulsation. This phenomenon consequently generates a double-line-frequency (100 Hz) voltage ripple on the DC-link capacitor, which causes an inherent contradiction in conventional voltage outer-loop control between steady-state ripple suppression and dynamic response speed. To address this issue, this paper proposes a control strategy based on an Adaptive Time-Delayed Feedforward Neural Network (Adaptive TD-FNN). The proposed method explicitly introduces the delayed voltage error of half a ripple period into the network state input, thereby achieving time-domain decoupling of the 100 Hz low-frequency disturbance. In addition, a physics-driven training framework is constructed by integrating the rectifier’s discrete difference equation, thereby strengthening the network’s capacity to learn the dynamic characteristics of the system. On this basis, a dynamic adaptive smoothness-weight penalty mechanism is designed to adjust the weighting factor of the current command smoothness constraint in the loss function according to the system operating state. Specifically, the penalty weight is increased under steady-state conditions to suppress command oscillations caused by ripple disturbances, while it is rapidly reduced during load or grid-voltage transients to release the network’s transient optimization capability. Simulation and experimental results show that the proposed Adaptive TD-FNN controller can simultaneously achieve smooth steady-state current command output and fast dynamic voltage regulation without introducing additional complex digital notch-filtering algorithms. Compared with conventional dual-loop control, the proposed strategy reduces the total harmonic distortion (THD) of the grid-side input current from 8.45% to 3.42%, satisfying grid-connected power quality requirements. Meanwhile, under large load transients and grid-voltage disturbance conditions, the DC-link voltage recovery time is about 40 ms, verifying the comprehensive advantages of the proposed method in ripple suppression, dynamic response, and operating-condition adaptability. Full article