Search Results (51)

Background: Retinoid signaling is implicated in regulating membrane-bound polyunsaturated fatty acids (PUFAs), which serve as substrates for oxylipin biosynthesis. Dysregulated vitamin A status and altered oxylipin profiles have both been associated with the development of metabolic diseases. However, whether early-life vitamin A deficiency (VAD) causally influences oxylipin metabolism and liver health remains unclear. Methods: C57BL/6J mouse pups were exposed to either a vitamin A-deficient (VD) or vitamin A-replete (VR) AIN-93G-based diet during the fetal and suckling periods, and they weremaintained on the same diet from weaning (3 weeks of age) to 9 weeks of age. Oxylipin composition in plasma, liver and cerebral tissues was analyzed by liquid chromatography–mass spectrometry. Hepatic and cerebral expressions of genes involved in inflammation, phospholipid and PUFA catabolism, and oxylipin synthesis were analyzed using RT-qPCR. Results: Dietary deprivation induced severe VAD, which significantly altered 21 oxylipins in the liver and 34 oxylipins in the cerebrum, but did not affect the plasma oxylipin profile. In the liver, all altered oxylipins were elevated by VAD, the majority being ω-6-derived species with pro-inflammatory properties. In contrast, 27 altered oxylipins were lower in the VD cerebrum, including more ω-3-derived species. Multivariate analysis identified 11,12-EpETrE, 8,9-EpETrE, and 20-HETE as key hepatic oxylipins distinguishing VAD. VAD also altered hepatic expression of genes involved in membrane phospholipid remodeling (PNPLA8, PLA2G6, LPCAT3), and oxylipin metabolism (ALOX5, EPHX2), and it upregulated inflammatory signaling in the liver only, while fibrosis markers (TGFB1, COL1A1) remained unchanged. Conclusions: These findings demonstrate that early-life VAD is associated with tissue-specific alterations in oxylipin metabolism and hepatic inflammatory responses. Full article

Fish nutritional value is a complex trait, highly influenced by fatty acid composition, which is correspondingly affected by a variety of factors, such as seasonality, abiotic conditions, and genetic background. Herein, the seasonal variations in lipid metabolism and the composition of fatty acids in three economically important mullet species (Chelon auratus, Chelon ramada, and Mugil cephalus) in an appropriate fisheries model marine area, Klisova Lagoon, Greece, were investigated. From seasonal sampling across one year, data regarding the sea temperature, fatty acid profiles in fish fillet, lipid-related gene expression (acc, hoad, and atgl), and key enzymatic activities (citrate synthase, HOAD, and lipase) in liver and muscle were obtained. Biochemical, molecular, and enzymatic analyses revealed pronounced interspecific and seasonal differences in lipid metabolism and the composition of fatty acids among Chelon auratus, Chelon ramada, and Mugil cephalus. M. cephalus exhibited strong metabolic plasticity, with enhanced lipid oxidation during colder periods and increased lipid synthesis and mobilization during warmer months. In contrast, C. ramada and C. auratus generally showed higher PUFA and ω-3 contents, although nutritional quality across all species was largely season-dependent, with colder periods favoring unsaturated fatty acid accumulation. Coordinated seasonal shifts in gene expression and enzyme activities reflected these temperature-driven metabolic regulation and distinct thermal-adaptation strategies. These metabolic traits support the ecological success of mullets in Mediterranean environments and highlight underutilized C. ramada and C. auratus mullet species as nutritionally valuable, sustainable alternatives for regional fisheries and aquaculture, supporting both sustainable fisheries and consumer awareness within the EU seafood market. Full article

The effect of high-gravity fields, generated by rapid rotation, on CO₂ adsorption in activated carbon beds is examined. Adsorption-desorption kinetics is monitored before, during, and after short rotation periods at up to 5000 rpm. Rotation induced a reproducible transient bump in headspace pressure, quantitatively attributed to a centrifugal free energy shift (~12.2 J/mol) that overfilled weak adsorption sites beyond their static equilibrium. The bump mechanism is described by fold catastrophe theory, with a critical angular velocity (ω_c = 3500 rpm) triggering a sudden transition to a high-occupancy branch. Post-rotation, constant-rate zero-order desorption from shallow sites overlapped with a slower pseudo-first-order adsorption process as deep, previously inaccessible pores became available, increasing CO₂ capacity by 2.5%. Kinetic modeling produced an apparent diffusivity of 1.2 × 10⁻⁵ m²/s and a structural accessibility time constant of ~25 h. Thermodynamic analysis showed that rotation improved the overall free energy of adsorption and altered entropy in a manner consistent with the observed adsorption-desorption sequence. These results demonstrate that rotational fields can enhance CO₂ uptake, modify kinetic pathways, and trigger threshold phenomena in porous adsorbents. Full article

This study investigated the anti-corrosion performance of multilayer polymeric coatings applied on 6005A and 6082 aluminum alloys under the influence of the monsoon tropical climate of Thailand. The coated samples, which represented the material used for the vehicle body of high-speed trains, were exposed to real atmospheric conditions of urban (Bangkok City) and marine (Songkhla City) environments. The maximum duration of the continuous exposure test was 18 months. After the exposure test, the physical deterioration characteristics of the coatings were examined with the aid of scanning electron microscopy (SEM) and a pull-off adhesion test. Electrochemical impedance spectroscopy (EIS) was performed in 3.5 wt% NaCl solution at 25 °C to evaluate the coatings’ anti-corrosion performance after various atmospheric exposure periods. Based on the EIS results, the low-frequency impedance of the exposed coatings remained above 10⁹ Ω·cm², indicating that the anti-corrosion coatings provided sufficient protection against atmospheric corrosion for the alloy. However, gradual degradation of the anti-corrosion coatings was observed, particularly in the marine-coastal environment. Quantitative estimation results suggested that the anti-corrosion coatings used in this study could provide service lives of approximately 8 and 11 years in marine-coastal and urban environments, respectively. Full article

This study proposed an effective capacitance (C_ec) for bare and conducting polymer-covered electrodes using electrochemical impedance spectroscopy (EIS). Bare electrodes show three regimes: potential-dependent Helmholtz capacitance, Gouy–Chapman–Stern diffusion capacitance (1 MHz–10 Hz), and complex low-frequency responses, deviating from semi-infinite Warburg diffusion (1 Hz–10 mHz). Polyaniline (PANI) and poly(3,4-ethylenedioxythiophene) PEDOT-based electrodes exhibit larger potential-dependent diffusion pseudocapacitance (1 MHz–10 Hz) and the absence of a Warburg tail or a nearly horizontal low-frequency slope at 0.01–0.026 (1 Hz–10 mHz). A high-frequency C_ec of a PANI membrane correlates with bulk electrolyte concentration, while bare electrodes are less affected and dominated by Helmholtz capacitance. The equivalent circuit of the time-dependent EIS impedance spectrum for bare electrodes and PANI and PEDOT-based electrodes shows parallel capacitor behavior in combination with high-frequency capacitance (1 MHz–10 Hz) and a low-frequency response (1 Hz–10 mHz). The mathematical simulation of effective capacitance C_ec with respect to time period t (f⁻¹) follows two time constants (τ = RC), representing double-layer capacitance or pseudocapacitance (τ₁) and complex low-frequency responses or Warburg diffusion (τ₂) for bare electrodes and conducting polymer-based electrodes, respectively. This simulation analysis also elucidates the frequency dependence of the Warburg characteristic frequency (ω) and the extension of the double-layer capacitance diffuse distance L_D for H⁺ with GC electrodes to approximately 7.37–15.15 μm over a time interval of ca. 1 s (t = f⁻¹). The diffusion coefficient D_i of K⁺ ion transfer through a PEDOT solid contact from 1 mC (0.1 µm) to 10 mC (1 µm) is in the range of 0.57–12 × 10⁻¹⁰ cm²·s⁻¹, following a power law with an exponent of 1.75 with respect to the polymerization time of PEDOT, which is inconsistent with Fick’s law. Full article

We provide sufficient conditions for the existence of $(\omega ,c)$-periodic solutions of a general class of nonlinear functional integral equations. This study extends and generalizes previous contributions in the literature. As an application of the developed theory, we establish the existence of $(\omega ,c)$-periodic solutions for recurrent neural networks with time-varying coefficients and mixed delays, as well as for a class of nonlinear Volterra–Stieltjes integral equations with infinite delay. Full article

Cement-based construction in cold regions faces severe challenges due to the dramatic retardation of hydration and strength development under sub-zero temperatures. Joule curing as a novel curing method showed certain advantages in solving this problem, while the curing efficiency was low for Joule curing under severely cold temperatures. This study systematically investigates the performance of graphene nanoplatelet (GNP)-modified electrically conductive cementitious composites under sub-zero temperature curing conditions. Joule curing method was employed to ensure a high-quality curing at ambient temperatures of −20 °C, −40 °C, and −60 °C. The results demonstrate that GNP incorporation significantly enhances electro-thermal performance. For the electrical conductivity of the specimens, the specimens containing 0.5 wt% GNP showed a much stable electric resistance development under severely cold environment, illustrating the value of 1169 Ω after 1 day Joule curing at the environmental temperature of −60 °C, which was 36% lower than the Ref. group. As for the curing temperature, the specimen with 0.5 wt% GNP effectively maintained the internal temperature within 50–60 °C during the 24 h curing period, even under extreme conditions. Mechanical tests reveal that the GNP-modified specimens exhibit remarkable strength retention, with the 0.5% GNP composite maintaining 86.3% of its compressive strength and 95.9% of its flexural strength at −60 °C compared to standard curing values. Microstructural characterization through XRD and TG analyses confirms that while the crystalline phase composition remains unchanged across different curing regimes, the hydration degree directly correlates with the mechanical performance, explaining the observed strength variations. MIP analysis further proved the advantage of Joule curing on refining the microstructure for the specimens. The findings establish that GNP modification, combined with Joule curing, presents an effective strategy for winter concrete construction, ensuring adequate strength development through enhanced electrical conductivity and controlled internal curing temperature, without altering the fundamental hydration chemistry. Full article

This paper presents a nonlinear vertical dynamic model of an electromagnetic suspension (EMS) system in maglev trains regulated by a dual nonlinear saturation controller (DNSC) under simultaneous resonance ($\Omega \cong {\omega }_s, {\omega }_s\cong 2{\omega }_c$). The governing nonlinear differential equations of the system are addressed analytically utilizing the multiple time-scale technique (MTST), concentrating on resonance situations obtained from first-order approximations. The suggested controller incorporates two nonlinear saturation functions in the feedback and feedforward paths to improve system stability, decrease vibration levels, and enhance passenger comfort amidst external disturbances and parameter changes. The dynamic bifurcations caused by DNSC parameters are examined through phase portraits and time history diagrams. The goal of control is to minimize vibration amplitude through the implementation of a dual nonlinear saturation control law based on displacement and velocity feedback signals. A comparative analysis is performed on different controllers such as integral resonance control (IRC), positive position feedback (PPF), nonlinear integrated PPF (NIPPF), proportional integral derivative (PID), and DNSC to determine the best approach for vibration reduction in maglev trains. DNSC serves as an effective control approach designed to minimize vibrations and enhance the stability of suspension systems in maglev trains. Stability evaluation under concurrent resonance is conducted utilizing the Routh–Hurwitz criterion. MATLAB 18.2 numerical simulations (fourth-order Runge–Kutta) are employed to analyze time-history responses, the effects of system parameters, and the performance of controllers. The evaluation of all the derived solutions was conducted to verify the findings. Additionally, quadratic velocity feedback leads to intricate bifurcation dynamics. In the time domain, higher displacement and quadratic velocity feedback may destabilize the system, leading to shifts between periodic and chaotic movements. These results emphasize the substantial impact of DNSC on the dynamic performance of electromagnetic suspension systems. Frequency response, bifurcation, and time-domain evaluations demonstrate that the DNSC successfully reduces nonlinear oscillations and chaotic dynamics in the EMS system while attaining enhanced transient performance and resilience. Full article

This paper investigates the existence of square-mean S-asymptotically $(\omega ,c)$-periodic solutions for a class of neutral impulsive stochastic differential equations driven by fractional Brownian motion, addressing the challenge of modeling long-range dependencies, delayed feedback, and abrupt changes in systems like biological networks or mechanical oscillators. By employing semigroup theory to derive mild solution representations and the Banach contraction principle, we establish sufficient conditions–such as Lipschitz continuity of nonlinear terms and growth bounds on the resolvent operator—that guarantee the uniqueness and existence of such solutions in the space ${\mathcal{S}AP}_{\omega ,c}([0,\infty ),L^2(\Omega ,\mathbb{H}))$. The important results demonstrate that under these assumptions, the mild solution exhibits square-mean S-asymptotic $(\omega ,c)$-periodicity, enabling robust asymptotic analysis beyond classical periodicity. We illustrate these findings with examples, such as a neutral stochastic heat equation with impulses, revealing stability thresholds and decay rates and highlighting the framework’s utility in predicting long-term dynamics. These outcomes advance stochastic analysis by unifying neutral, impulsive, and fractional noise effects, with potential applications in control theory and engineering. Full article

Background and Objectives: Midlife represents a critical window for the emergence of metabolic risk factors. This study aimed to investigate age- and sex-related changes in lipid profiles, body composition, oxidative stress, and fatty acid content. Materials and Methods: This cross-sectional study included adults grouped by age: <30, 30–39, and 40–49 years. The assessments covered body composition (fat mass, fat distribution, and lean mass), fasting lipids, inflammation markers measurements, and platelet fatty acids evaluation. Results: In total, 169 adults took part in this study (60 men and 109 women), aged 36.30 ± 6.25 years. Fat mass and its regional distribution were higher after age 40, especially in females. In women, fat mass was lower in the thirties and higher again in the forties, while, in men, fat accumulation was progressive. Participants aged 40–49 had a significantly worse metabolic profile than younger individuals. Statistically significant higher total cholesterol, LDL cholesterol, triglycerides, and glucose were shown in the 40–49-years group when compared to younger groups. Malondialdehyde was higher in the 40–49-years vs. 30–39-years group (105.83 vs. 99.72, p = 0.034). In women aged 40–49, a more adverse lipid and glycemic profile was observed compared to younger groups. Platelet fatty acids in the 40–49-years group showed higher polyunsaturated fatty acids and ω6 percentages (12.85% vs. 10.14%, p = 0.046 and 11.44% vs. 8.79%, p = 0.031), including higher linoleic (8.80 ± 5.18 vs. 6.97 ± 5.05, p = 0.045), arachidonic (2.64 ± 2.64 vs. 1.82 ± 1.73, p = 0.030), and docosahexaenoic (0.61 ± 0.86 vs. 0.31 ± 0.49, p = 0.008) acids, when compared to younger groups. Fat mass strongly correlated with insulin resistance, triglycerides, and CRP, and inversely with HDL-C. Conclusions: Significant age-related changes in body composition, metabolic biomarkers, and platelet fatty acid profiles occur after the age of 40, with distinct gender-specific patterns. The fifth decade of life is a transitional period characterized by central adiposity, deteriorating metabolic profiles, and altered fatty acid composition, especially in women. Full article

In this study, a carbon felt (CF)-based ternary composite anode was developed through the decoration of nickel cobaltite (NiCo₂O₄) nano-needles and subsequent in situ electropolymerization of polypyrrole (PPy). The structural and electrochemical properties of the modified electrodes were systematically characterized. The CF/NiCo₂O₄/PPy anode demonstrated significantly enhanced bioelectrochemical activity, achieving a peak current density of 96.0 A/m² and a steady-state current density of 28.9 A/m², which were 4.85 and 5.90 times higher than those of bare carbon felt, respectively. Geobacteriaceae is a type of electrogenic bacteria. It was hardly detected on the bare CF substrate; however, in the ternary CF/NiCo2O4/PPy electrode, the relative abundance of Geobacteriaceae significantly increased to 43%. Moreover, the composite electrode exhibited superior charge storage performance, with a total charge (Q_t) of 32,509.0 C/m² and a stored charge (Q_s) of 3609.0 C/m² measured under a 1000 s charging/discharging period. The MFC configured with the CF/NiCo₂O₄/PPy anode reached a maximum power density of 1901.25 mW/m² at an external resistance of 200 Ω, nearly six times that of the unmodified CF-based MFC. These improvements are attributed to the synergistic interaction between the pseudocapacitive NiCo₂O₄ and conductive PPy, which collectively facilitate electron transfer, promote microbial colonization, and enhance interfacial redox kinetics. This work provides an effective strategy for designing high-performance MFC electrodes with dual functionality in energy storage and power delivery. Full article

A new spectroscopic study of HR 4049, a post-AGB star in a binary system, based on échelle spectra taken between 2019 and 2025 with the 0.81 m telescope of the Three College Observatory (North Carolina, USA) at a resolution of R ≈ 12,000 is reported. A cross-correlation analysis of 73 spectra of a single C i multiplet in the 4760–4780 Å range yielded the following orbital parameters: the orbital period $P=428.474\pm 0.002$ days, eccentricity $e=0.29\pm 0.01$, argument of periastron $\omega ={242.3}^{\circ }\pm {0.3}^{\circ }$, epoch of periastron $T_0=\mathrm{2,458,383.2}\pm 0.6$, heliocentric systemic radial velocity $\gamma =-30.12\pm 0.09$ km s⁻¹, and semi-amplitude of the radial velocity curve $K_1=15.52\pm 0.13$ km s⁻¹. Phase-dependent variations of the Hα line profile indicate dynamic processes in the circumstellar environment. The luminosity of HR 4049 was refined using the Gaia EDR3 parallax ($0.71\pm 0.10$ mas), corresponding to a distance of $1397\pm 170$ pc, and the average visual magnitude in the brightest state ($m_V=5.35$ mag). The derived luminosity, $log(L/L_{\odot })=4.22\pm 0.12$, suggests an initial mass of 3.0–4.0 $M_{\odot }$. Analysis of the mass function and most probable orbital inclinations (60°–75°) leads to current masses of $\sim 0.75M_{\odot }$ for the primary and $0.70$–$0.82M_{\odot }$ for the secondary component. The results confirm the system’s long-term orbital stability and provide further insights for future research into the nature of post-AGB binaries. Full article

The mismanagement of plastic waste, organic waste, and the shortage of electricity in remote villages has created significant challenges for industries and governments. Therefore, this research aims to utilize the fungus Trichoderma sp. as a catalyst in microbial fuel cells, where the novelty of the research is the generation of electricity and the degradation of plastic simultaneously. In this study, single-chamber microbial fuel cells were constructed using carbon (anode) and zinc (cathode) electrodes. The substrate consisted of 20 gr of potato waste and 1.5 × 1.5 cm samples of plastic waste, all combined in 390 mL of Bushnell broth, into which Trichoderma sp. was inoculated. The highest electrical readings were recorded on day 23, showing values of 5.648 ± 0.093 mA and 0.479 ± 0.025 V. On the same day, the pH level was measured at 7.046 ± 0.314, and the substrate’s electrical conductivity was found to be 155.135 ± 2.569 mS/cm. Over the 45-day monitoring period, the chemical oxygen demand decreased by 78.67%. The microbial fuel cells achieved a maximum power density of 68.140 ± 2.418 mW/cm² at a current density of 4.719 mA/cm², with an internal resistance of 23.647 ± 1.514 Ω. Analysis of the plastic using FTIR (Fourier Transform Infrared Spectroscopy) revealed a decrease in the intensity of spectral bands associated with hydroxyl groups, C-H structural groups, methyl groups, and C=C bonds. Additionally, SEM (Scanning Electron Microscopy) images demonstrated a reduction in the thickness of the plastic film and the formation of voids and sheets, highlighting the potential of Trichoderma sp. for plastic degradation. Full article

The study of long-term behavior in stochastic systems is critical for understanding the dynamics of complex processes influenced by randomness. This paper addresses the existence and uniqueness of Stepanov-like pseudo S-asymptotically $(\omega ,c)$-periodic solutions for a class of stochastic integro-differential equations. These equations model systems where the interplay between deterministic and stochastic components dictates the overall dynamics, making periodic analysis essential. The problem addressed in this study is the lack of a comprehensive framework to describe the periodic behavior of such systems in noisy environments. To tackle this, we employ advanced techniques in stochastic analysis, fixed-point theorems and the properties of $L^1$- and $L^2$-convolution kernels to establish conditions for the existence and uniqueness of mild solutions under these extended periodicity settings. The methodology involves leveraging the decay properties of the operator kernels and the boundedness of stochastic integrals to ensure well-posedness. The major outputs of this study include novel results on the existence, uniqueness and stability of Stepanov-like pseudo S-asymptotically $(\omega ,c)$-periodic solutions, along with illustrative example demonstrating their applicability in real-world stochastic systems. Full article

In this paper, we derive sufficient conditions that guarantee an description of long-time asymptotic behavior of the solution to the Cauchy problem governed by a linear neutron transport equation with a partially elastic collision operator under periodic boundary conditions. Our strategy involves showing that the strongly continuous semigroups ${\left(e^{t(T+K_e)}\right)}_{t\ge 0}$ and ${\left(e^{t(T+K_c+K_e)}\right)}_{t\ge 0}$, generated by the operators $T+K_e$ and $T+K_c+K_e$, respectively, have the same essential type. According to Proposition 1, it is sufficient to show that remainder term in the Dyson–Philips expansion is compact. Our analysis focuses on the compactness properties of the second-order remainder term in the Dyson–Phillips expansion related to the problem. We first show that $R_2\left(t\right)$ is compact on $L^2(\mathsf{\Omega }\times V,dxdv)$, and, using an interpolation argument (see Proposition 2), we establish the compactness of $R_2\left(t\right)$ on $L^p(\mathsf{\Omega }\times V,dxdv)$-spaces for $1<p<+\infty$. To the best of our knowledge, outside the one-dimensional case, this result is known only for vaccum boundary conditions in the multidimensional setting. However, our result, Theorem 1, is new for periodic boundary conditions. Full article