Search Results (353)

This paper presents a new, quick method for testing the content of magnetic forms of iron in organic soils. These forms are an important marker of changes occurring in the environment. This method is based on impedance spectroscopy of a measuring coil inside which the tested material is placed—the material serves as the core of the coil. Unlike EIS (electrochemical impedance spectroscopy), the new method does not use electrodes, is sensitive to magnetic forms of iron, and is non-contact (the measuring current does not flow through the tested material). The results of research on three materials, including brown peat and silt with plant detritus, are presented in this paper. The results showed that changes in the standardized components of the measuring coil impedance in the frequency range of 100–135 kHz enable the determination of the content of ferromagnetic iron oxide (Fe₃O₄). The proposed method is very sensitive to soil oxide content in the range of 0% to 8%. Additionally, elemental composition analysis was performed using ICP-AES (inductively coupled plasma–atomic emission spectroscopy), which allowed for comparison of iron and other metal content with impedance measurement results. The final results confirm the usefulness of impedance spectroscopy as a non-destructive method for studying sedimentary environments and assessing their mineral properties. Full article

This study investigated the metabolic mechanisms driving physiological functional remodeling in RFM by analyzing plasma biochemical parameters and metabolomic profiles at key peripartum timepoints (21 and 7 d prepartum and 4 h postpartum), integrated with placental and fetal membrane metabolic characteristics. The results revealed that RFM cows exhibited significant negative energy balance (NEB) as early as 21 days before parturition, characterized by elevated plasma levels of non-esterified fatty acids, β-hydroxybutyrate, and malondialdehyde, alongside reduced activity of antioxidant enzymes (GSH-Px, CAT) (p ≤ 0.05). Metabolomic analysis demonstrated persistent lipid metabolism dysregulation, amino acid imbalance, and nucleotide metabolism disturbances in RFM cows from 21 days prepartum to 4 h postpartum, indicating premature mobilization of adipose and muscle tissues. Further metabolomic analyses of the placenta and fetal membranes confirmed that metabolic dysfunction compromises energy supply during parturition, adversely affecting immune homeostasis and extracellular matrix degradation in the placenta and fetal membranes of RFM dairy cows. These physiological dysfunctions have the potential to impede the timely expulsion of fetal membranes after calving. In conclusion, RFM is closely associated with early-onset metabolic dysfunction during the periparturient period, where insufficient energy supply due to NEB, oxidative stress, and immune-endocrine disruptions collectively impair normal fetal membrane detachment. Full article

Polyhydroxybutyrate (PHB) is considered a coating material capable of limiting the corrosion of biodegradable metallic implants due to its biocompatibility and ability to form a physical barrier. In this study, PHB was deposited on commercial AZ91D magnesium alloy using the spin coating technique. To improve adhesion at the polymer–substrate interface, the magnesium substrates were subjected to atmospheric pressure plasma treatment for different exposure times (5, 10, or 15 min) before coating. The optimal treatment time of 5 min significantly increased substrate wettability and surface free energy, facilitating stronger PHB adhesion. In addition, the PHB coatings were subjected to atmospheric pressure plasma treatment for 5, 10, or 15 s to evaluate potential surface modifications. Corrosion behavior under simulated physiological conditions was assessed via potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) in HANK’s solution at 37 °C. Pull-off tests were used to evaluate the adhesion strength between the coating and the substrate under each treatment condition. The results showed a significant decrease in the corrosion rate (V_corr), from 4.083 mm/year for bare Mg-AZ91D to 0.001 mm/year when both the substrate and the polymer received plasma treatment. This indicates that the treatment modifies surfaces and improves interfacial bonding, enhancing polymer–metal interaction and producing durable, biocompatible coatings for medical implants. Full article

We report the synthesis and multifunctional characterization of copper-reinforced Ba_0.85Sr_0.15TiO₃ (BST) ceramic composites with Cu contents ranging from 0 to 40 wt%, prepared by a sol–gel route and densified using spark plasma sintering (SPS). X-ray diffraction and FT-IR analyses confirm the coexistence of cubic and tetragonal BST phases, while Cu remains as a chemically separate metallic phase without detectable interfacial reaction products. Microstructural observations reveal abnormal grain growth induced by localized liquid-phase-assisted sintering and progressive Cu agglomeration at higher loadings. Scanning electron microscopy reveals abnormal grain growth, with the average BST grain size increasing from approximately 3.1 µm in pure BST to about 5.2 µm in BST–Cu40% composites. Optical measurements show a continuous reduction in the effective optical bandgap (apparent absorption edge) from 3.10 eV for pure BST to 2.01 eV for BST–Cu40%, attributed to interfacial electronic states, defect-related absorption, and enhanced scattering rather than Cu lattice substitution. Electrical characterization reveals a percolation threshold at approximately 30 wt% Cu, where AC conductivity and dielectric permittivity reach their maximum values. Impedance spectroscopy and equivalent-circuit analysis demonstrate strong Maxwell–Wagner interfacial polarization, yielding a maximum permittivity of ~1.2 × 10⁵ at 1 kHz for BST–Cu30%. At higher Cu contents, conductivity and permittivity decrease due to disrupted Cu connectivity and increased porosity. These findings establish BST–Cu composites as tunable ceramic–metal systems with enhanced dielectric and optical responses, demonstrating potential for specialized high-capacitance decoupling applications where giant permittivity is prioritized over low dielectric loss. Full article

The intrinsic limitations of Ti₃C₂T_x electrodes, specifically low interfacial charge-transfer efficiency and structural degradation in strongly acidic environments, hinder their performance in high-rate aqueous supercapacitors. Herein, we report a synergistic strategy combining nitrogen plasma surface engineering with a redox-active ascorbic acid electrolyte to optimize the electrode/electrolyte interfacial kinetics. By systematic investigation, the Ti₃C₂T_x supercapacitor obtained by a 10-min plasma duration (N10P-AA) achieved the optimal balance between activating surface sites and preserving the conductive Ti–C framework integrity. The ascorbic acid electrolyte broadened the potential window to approximately 0.7 V, and N10P-AA exhibited the lowest charge-transfer impedance and superior rate capability, retaining a relatively high Coulombic efficiency (>72%) even at a high scan rate of 10,000 mV·s⁻¹. The EIS results and kinetics analysis (b values) confirmed that the moderate plasma activation effectively promoted more surface-dominated charge storage kinetics and mitigated diffusion limitation, consistent with reduced charge-transfer resistance and a smaller Warburg slope. The XPS results revealed that the 10-min treatment suppressed detrimental oxidation during cyclings and facilitated the formation of electrochemically favorable hydroxylated surface functional groups. This work demonstrates a feasible surface electrolyte co-engineering strategy for modulating the interfacial behavior of MXene, which is of great significance for future high-efficiency aqueous electrochemical energy storage and potential biosensing applications. Full article

The plant plasma membrane serves as the primary interface for perceiving extracellular signals, a function largely mediated by plasma membrane receptors (PMRs). In wheat (Triticum aestivum), the functional characterization of these receptors is impeded by the species’ large, hexaploid genome, which results in extensive gene duplication and functional redundancy. This review synthesizes current knowledge on wheat PMRs, covering their diversity, classification, and signaling mechanisms, with a particular emphasis on their central role in plant immunity. We highlight the remarkable structural and functional diversification of PMR families, which range in size from 10 members, as seen in the case of wheat leaf rust kinase (WLRK), to over 3424 members in the receptor-like kinase (RLK) family. Furthermore, we reviewed the role of PMRs in being critical for detecting a wide array of biotic stimuli, including pathogen-associated molecular patterns (PAMPs), herbivore-associated molecular patterns (HAMPs), and symbiotic signals. Upon perception, PMRs initiate downstream signaling cascades that orchestrate defense responses, including transcriptional reprogramming, cell wall reinforcement, and metabolic changes. The review also examines the complex cross-talk between immune receptors and other signaling pathways, such as those mediated by brassinosteroid and jasmonic acid receptors, which underpin the delicate balance between growth and defense. Finally, we bridge these fundamental insights to applications in crop improvement, delineating strategies like marker-assisted selection, gene stacking, and receptor engineering to enhance disease resistance. After identifying key obstacles such as genetic redundancy and pleiotropic effects, we propose future research directions that leverage multi-omics, systems biology, and synthetic biology to fully unlock the potential of wheat PMRs for sustainable agriculture. Full article

In many industrial applications, engine, turbine, and rotor components are coated with thin layers that protect them from corrosion, high temperatures, or pressure. This paper presents a fast and effective method for testing such protective coatings. For this purpose, an eddy current probe consisting of a single coil was designed and constructed. The high sensitivity of the probe was achieved by using a pot core, which significantly reduced magnetic flux losses. In addition to the substrate, the test samples also contained carbide coatings or thermal barrier coatings (TBCs), which were sprayed with an Axial III triple-plasma torch or a single-electrode torch. The use of different process parameters made it possible to obtain coatings of varying thickness, which were determined using a scanning electron microscope (SEM). Measurements of the probe impedance components were performed in the frequency range from 500 Hz to 50 kHz. In all cases, based on the analysis of changes in resistance and reactance, it was possible to distinguish each of the tested samples. Even slight changes in thickness of only 9 μm caused significant changes in probe impedance, enabling effective testing of carbide coatings and TBCs. Full article

In this paper, the dependence of the microstructure and properties on Spark Plasma Sintering modes of an AlN-35 β-SiC (wt.%) composite is investigated. It was found that the use of a heating rate of 100 °C/min during the sintering process of the AlN-35 β-SiC (wt.%) composite leads to the formation of a solid solution (AlN)_x–(SiC)_x−1 at 1900 °C during 5 min, and under a pressure of 50 MPa. It was observed that, at a heating rate of 50 °C/min and a pressure of 25 MPa, yttrium oxide used as a sintering additive impedes the diffusion of SiC into AlN. This impedes the formation of a solid solution (AlN)_x–(SiC)_x−1 and helps preserve SiC grains, which act as the main absorbing phase in the obtained composites. It is shown that the use of sintering additives and SPS technology allows obtaining samples with a density of 3.26 g/cm³, which coincides with the theoretical value of the composite. The dielectric characteristics and absorbing properties of sintered materials are determined in the frequency bands from 5.6 to 26 GHz. It has been discovered that the reflection, transmission, and absorption coefficients can be regulated depending on the thickness of the sample. In addition, it is shown that composites containing solid solutions and silicon carbide grains in their structures have the best absorbing properties. On the other hand, the material containing only solid solutions is a promising material that can be used as microwave filters. Full article

In this work, plasma nitriding was carried out to improve the corrosion resistance of API 5L X70 steel. The process was conducted at different treatment times, 4, 6, 8, and 10 h, to determine which one provides greater resistance to corrosion. The conditions under which the nitriding was carried out were as follows: a mixture of 20% N₂ and 80% H₂ at 3 torr pressure, a current of 2.6 × 10⁻⁶ A, a voltage of 360 V, and the temperature inside the plasma chamber was 550 °C. The blank and nitrided materials were characterized using dispersive energy spectroscopy and scanning microscopy to study their morphology and chemical composition. In addition, open potential circuit, electrochemical impedance spectroscopy, and potentiodynamic polarization curves in simulated soil solution were performed to evaluate the materials’ corrosion resistance. The treatment achieved at 10 h presented the greatest corrosion resistance, reducing the corrosion current density up to three orders of magnitude. The thickness reached 678.75 µm for this condition. Full article

Background: Platelets have conventionally been viewed as cellular fragments crucial for hemostasis; nonetheless, their extensive secretome of cytokines and growth factors has been increasingly acknowledged as a significant regulator of inflammation and tissue healing at the ocular surface. Aims: The objective of this narrative review is to synthesize existing knowledge of platelet biology with new findings about the therapeutic use of platelet-derived products in dry eye disease (DED). Methods: A qualitative review of the PubMed, Scopus, and Web of Science databases up to June 2025 identified preclinical, translational, and clinical studies assessing platelet-rich plasma (PRP), plasma rich in growth factors (PRGF), platelet lysate, and autologous serum tears for dry eye disease (DED) and associated ocular surface disorders. Results: Platelet-derived formulations have exhibited reliable immunomodulatory and regenerative effects by diminishing inflammatory signaling, lowering cytokine expression, and facilitating epithelial and neurotrophic restoration. Clinical investigations have indicated enhancements in tear film stability, corneal staining, and patient-reported symptoms, especially in cases of moderate-to-severe or refractory illness. Nonetheless, methodological diversity, inconsistent preparation techniques, and restricted sample sizes have impeded comparability among experiments. Conclusions: Platelet-derived treatments constitute a biologically viable and clinically promising strategy for the management of dry eye disease (DED). Future research must emphasize the standardization of preparation protocols, the identification of predictive biomarkers such as transforming growth factor-β1 (TGF-β1), nerve growth factor (NGF), and matrix metalloproteinase-9 (MMP-9), as well as the design of multicenter randomized controlled trials to guarantee reproducible, GMP-compliant clinical applications. Full article

Vitamin D deficiency (VDD) is a widespread human condition closely associated with musculoskeletal disorders, involving alterations in body composition and systemic inflammation. In this cross-sectional study, 1075 adults were classified into a VDD (n = 304) group and a VD sufficient (VDS) group (n = 771). Body composition measurements, including the fat mass-to-weight ratio (FM/WT), were assessed using bioelectrical impedance analysis. Plasma levels of IL-9, IL-34, and MCP-1 were also measured. Data on osteoporosis (OP) and knee osteoarthritis (KOA) were collected. Regression analyses indicated that FM/WT was independently associated with VDD, which in turn was linked to elevated IL-34 levels. Individuals with VDD had a significantly higher prevalence of OP and KOA compared with those with VDS. Structural equation modeling confirmed and quantified these associations, suggesting that FM/WT is a significant predictor of VDD status (β = 0.305, 95% CI: 0.231–0.367). VDD is directly associated with elevated IL-34 levels (β = 0.353, 95% CI: 0.308–0.398), while IL-34 levels, in turn, are a possible cause of KOA (β = 0.573, 95% CI: 0.460–0.687) and OP (β = 0.433, 95% CI: 0.329–0.536). Our data clearly demonstrate existence of a physiological-pathological continuum: obesity-VDD-IL-34 and both OP and KOA. Full article

This study investigates the influence of current density distribution on the hardening behavior of 20GL cast steel during electrolytic plasma processing (EPP). Experimental and numerical methods were combined to establish the relationship between discharge dynamics, heat flux, microstructural transformation. Electrolytic plasma hardening was carried out at cathodic voltages of 150 V and 250 V in a 20% Na₂CO₃ solution. The transient evolution of current density was analyzed using a 3D COMSOL Multiphysics model incorporating a vapor–gas shell (VGS) represented as a distributed impedance layer with realistic conductivity and permittivity. High-speed video confirmed that microdischarges preferentially initiate at sample corners, where modeling also predicts local current concentration and heat flux up to 12 MW/m². Experimental current density values (3–4 × 10⁴ A/m²) showed good agreement with the simulations. Microhardness tests revealed that increasing voltage from 150 V to 250 V increases the thickness of the hardened layer (from ~250 µm to ~600 µm) and raises surface hardness (up to 750 HV), while polarization tests showed a 40% reduction in corrosion rate. The results highlight that current density distribution governs the non-uniformity of thermal effects and surface strengthening during EPP, emphasizing the importance of electrode alignment and VGS stability for uniform hardening. Full article

There is a knowledge gap about the effect of pharmaceutical agents on the biodegradation of Mg-based resorbable implants. The present work investigates how three common antibiotics and three anti-inflammatory drugs affect the corrosion of high-purity Mg, with and without ceramic and hybrid ceramic/polymeric coatings, using electrochemical impedance spectroscopy and hydrogen evolution tests. A Ca-P-Si-based ceramic coating is developed using plasma electrolytic oxidation (PEO), after the AC voltage and frequency parameters are optimized. A hybrid coating included a PEO and a poly(ε-caprolactone) (PCL) top layer formed by dip coating. High-purity Mg exhibited an instantaneous onset of corrosion with a corrosion rate of 90 μm/year after 24 h of immersion in a modified α-MEM. A hybrid PEO/PCL coating prevents the onset of corrosion for at least 5 h and reduces the H₂ evolution during the following 90 h by two times by the precipitation of 5–40 μm thick Ca-P surface deposits. Gentamicin, naproxen, streptomycin, ciprofloxacin and paracetamol were found to be corrosion accelerators with respect to bare h.p. Mg, whereas aspirin was found to be an inhibitor. Streptomycin-functionalized PEO/PCL system exhibited an active protection mechanism, triggered upon the release of the coating and substrate cations, associated with the coating defect-blocking action of the insoluble Me(II)-streptomycin chelates. Full article

Hydrophilic polymer–osmium complexes enhance electron transfer between enzymes and electrodes in biosensors. In this study, hydrophobic poly(4-vinylpyridine) (PVP) was quaternized with 2-bromoethanol to synthesize water-soluble PVP(Q)-C₂H₄OH polymers (MW 60,000 and 160,000). The resulting PVP(Q)-C₂H₄OH-Os(dmo-bpy)₂Cl complexes were verified by UV-Vis, FT-IR, 1H NMR, SEM-EDS, and zeta potential analyses, confirming successful quaternization and osmium coordination with good dispersion stability. Electrochemical tests (cyclic voltammetry, multi-potential step, amperometry) demonstrated that electrodes with quaternized mediators showed greatly enhanced catalytic currents for glucose (0–20 mM), with sensitivities of 6.9791 (MW 60,000) and 6.6279 μA·mM⁻¹·cm⁻² (MW 160,000), respectively, which were 6.6–10.3 times higher than those of non-quaternized polymers. Selectivity tests showed negligible interference from common species such as ascorbic acid, dopamine, uric acid, and serotonin. Continuous glucose monitoring (CGM) electrodes were fabricated by immobilizing the mediator and glucose dehydrogenase on silanized Au electrodes. SEM, scan rate, and impedance analyses confirmed stable binding. The modified electrodes showed strong linearity (R² = 0.992) and high sensitivity (2.56 μA·mM⁻¹·cm⁻²), and good stability, maintaining ~82% activity for seven days. Human plasma testing validated accurate glucose detection (6.05 mM), consistent with physiological levels. Overall, quaternized PVP(Q) mediators significantly improved solubility and electron transfer, enabling the development of a stable, selective glucose sensor suitable for CGM applications. Full article

Background: Right heart failure (RHF) in dogs is marked by pathological fluid redistribution and extracellular fluid (ECF) accumulation, which intensifies cardiac work-load and disrupts systemic homeostasis. This study aimed to validate the clinical utility of phase angle (PhA), a key biomarker derived from bioelectrical impedance analysis (BIA), as a non-invasive and real-time indicator of fluid distribution abnormalities in canine RHF. PhA reflects cellular integrity and fluid balance, making it a promising tool for detecting ECF accumulation, one of the hallmark features of RHF. Additionally, the study assessed the feasibility and clinical applicability of the InBody M20 device in veterinary cardiology, supporting its potential role in monitoring and managing fluid-related complications in dogs with RHF. Methods: A total of 110 canine patients presenting to the Tokyo University of Agriculture and Technology Veterinary Hospital were enrolled and categorized into three groups: right-sided heart failure (RHF), left-sided heart failure (LHF), and healthy controls. Phase angle (PhA) was measured using the InBody M20 device, and plasma osmolality (OSM) was also assessed. Additionally, the effects of body weight and age on PhA values were analyzed to account for potential confounding factors. Results: Dogs in the RHF group exhibited significantly lower phase angle (PhA) values and higher plasma osmolality (OSM) compared to those in the LHF and control groups. A strong positive correlation was observed between PhA and OSM (r = 0.9211, p < 0.0001). Additionally, PhA measured at 5 kHz demonstrated a significant negative correlation with body weight (r = –0.4536, p = 0.0007), while PhA at 50 kHz showed a significant negative correlation with age (r = –0.3219, p = 0.0176). Conclusions: PhA is a reliable and non-invasive biomarker for assessing extracellular fluid accumulation and diagnosing right heart failure in dogs. Its strong correlation with plasma osmolality, as well as its associations with body weight and age, highlights its clinical relevance for comprehensive fluid status evaluation. The findings support the feasibility and applicability of using the InBody M20 device in veterinary cardiology to monitor and manage fluid-related complications in canine patients. Full article