Search Results (1,117)

Luteolin and its derivative glycosides (cynaroside, orientin and isoorientin) are compounds with a flavonoid structure of plant origin. There are different studies in the literature on the antioxidant capacities of the structures and their inhibition effects on some enzymes. In this study, the antioxidant capacities of each structure were determined comparatively, and their inhibitory effects against enzymes associated with different diseases such as acetylcholinesterase, butyrylcholinesterase, α-glycosidase and α-amylase were evaluated by comparative investigation in vitro and in silico. Antioxidant capacities were determined for each structure by iron ions (Fe³⁺), cupric ions (Cu²⁺), Fe³⁺−Triphenyltetrazolium chloride (TPTZ) reduction methods and 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), N,N-dimethyl-p-phenylenediamine (DMPD) radical scavenging methods. According to the results obtained, it was determined that the antioxidant capacities of the structures were close to or better than butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), trolox, α tocopherol and ascorbic acid, which are used as standard antioxidants. The results of the study, which was conducted to determine the inhibition effects of the structures on the determined enzymes, were found to coincide experimentally and theoretically. According to the inhibition results, the best inhibitors were found as orientin (IC₅₀: 27.729 nM) for the human carbonic anhydrase I (hCA I), cynaroside (IC₅₀: 18.24 nM) for the human carbonic anhydrase I (hCA II), isoorientin (IC₅₀: 1.93 nM) for the acetylcholinesterase (AChE), and cynaroside (IC₅₀: 6.41 and 7.15 nM) for the butyrylcholinesterase (BChE) and α-glycosidase enzymes. Additionally, absorption, distribution, metabolism, and excretion (ADME) profiles and toxicity assessments of the structures were determined in a virtual environment. Full article

This study evaluates the effect of decorative ceramic screen printing on the optical and photovoltaic performance of glass covers intended for building-integrated photovoltaics (BIPV). Nine ceramic-printed glass samples with different colors and optical densities were compared with a 4 mm Optiwhite reference glass and a bare silicon solar cell. The samples were characterized by UV-VIS-NIR spectrophotometry, energy-dispersive X-ray spectroscopy (EDS), and electrical measurements under simulated AM 1.5G irradiation at 1000 W/m². The optical results showed that the Optiwhite reference provided the highest transmittance, whereas the printed samples exhibited lower transmission, typically in the range of 60–80% in the visible region, depending on the coating type. Among the decorative variants, sample 1 showed the highest transparency, while sample 6 exhibited the lowest transmittance. The spectral behavior of the coated glasses indicates that the ceramic layers modify the photon flux reaching the solar cell through wavelength-dependent absorption and scattering effects. The photovoltaic measurements confirmed a clear relationship between decorative coating and electrical performance. Relative to the Optiwhite-covered reference cell, the printed samples showed power losses ranging from approximately 17% to 32%, with sample 1 achieving the highest maximum power among the decorative variants at 1.41 W, and sample 4 the lowest at 1.16 W. The main electrical effect of the ceramic coatings was a reduction in short-circuit current, whereas the open-circuit voltage remained nearly constant across the tested samples. EDS analysis identified the presence of ceramic-layer constituents associated with silica-, zinc-, titanium-, iron-, cobalt-, aluminum-, and fluorine-containing compounds, supporting the interpretation of vitrified decorative coatings formed during high-temperature processing. Overall, the results demonstrate that decorative ceramic printing can provide a practical compromise between architectural appearance and photovoltaic output when the optical density of the coating is appropriately controlled. Full article

Flotation tailings and metallurgical slags from mining often contain toxic Pb, Cd, and Zn. In this study, we evaluated the in situ immobilization of Pb, Cd, and Zn in a Pb–Zn flotation tailing and a smelting slag by adding representative amendments: phosphate-based (ammonium phosphate, phosphoric acid, glassy fertiliser), cementitious (Portland cement), and iron-based (bog iron ore) materials at 1–10% (w/w). Treated samples underwent EPA-TCLP and pH-dependent leaching tests (pH 3–10), with Pb, Cd, and Zn measured by atomic absorption spectroscopy. The untreated tailing leached hazardous Pb (~60 mg/L) and elevated levels of Cd (~0.7 mg/L) and Zn (~53 mg/L), whereas the untreated slag leached negligible metal concentrations. All amendments reduced metal release in a dose-dependent manner. Phosphate amendments were most effective (e.g., 10% H₃PO₄ cut tailing Pb by 80%, Cd by 60%, and Zn by 30%), while cement and iron additions had much weaker effects. Solid-phase XRD and SEM-EDS analyses indicated the formation of stable calcium–phosphate minerals on sulfide surfaces after phosphate treatment. These findings suggest that low-cost phosphate additives (~5–10%) can substantially immobilize Pb, Cd, and Zn in such wastes. However, under strongly acidic conditions (pH < 3), some remobilization occurred, highlighting the need for further validation. This work provides practical guidance for waste managers on selecting in situ stabilization strategies for Pb–Zn mine wastes. Full article

Iron is an essential micronutrient that plays a central role in numerous biological processes. Despite its relatively low abundance in the human body, iron is particularly critical for brain function. Systemic and cerebral iron homeostasis is tightly regulated through coordinated mechanisms involving absorption, transport, storage, and recycling. Within the brain, iron metabolism is further controlled by the blood–brain barrier and specialized neural cell populations, including neurons, astrocytes, oligodendrocytes, and microglia. Iron is indispensable for neurodevelopment, supporting neurogenesis, myelination, and neurotransmitter synthesis. However, both iron deficiency and iron overload have detrimental consequences. Early-life iron deficiency disrupts neural development and leads to long-lasting cognitive, motor, and behavioral impairments, whereas excessive iron accumulation promotes oxidative stress, ferroptosis, and neuroinflammation. These mechanisms have been described to contribute to the pathogenesis of major neurodegenerative disorders, including Alzheimer’s disease, Parkinson’s disease, neurodegeneration with brain iron accumulation, and amyotrophic lateral sclerosis. This review first outlines systemic and brain iron metabolism, highlighting how neural cells regulate homeostasis. Next, it examines iron’s physiological roles, particularly in neurogenesis and neurodevelopment. Finally, it explores iron’s involvement in neurodegenerative diseases, emphasizing neuroinflammation as a primary mechanism of iron toxicity. Full article

This article focuses on the research and development of innovative polymer-concrete composites for the manufacture of precision machine tool frames and critical mechanical engineering components. The relevance of this work stems from the need to replace traditional cast iron and cement concrete with materials with superior damping properties and thermal stability. The polymer matrix used in this study was ED-20 epoxy-diane resin, modified with (FAM) furan resin and cured with polyethylenepolyamine (PEPA), which together ensured minimal linear shrinkage (less than 0.5–1%) during polymerization. The focus was on the effect of multimodal filler distribution, including quartz sand, gabbro, and basalt, as well as reinforcing additives such as silicon carbide and fiberglass, on the final performance characteristics of the material. Experimental studies determined the key physical and mechanical parameters of the obtained samples. The results showed that the optimized composition (Smp_001) exhibited compressive strength up to 92.3 MPa, significantly exceeding that of standard high-strength concrete. It was established that the use of silicon carbide and glass fiber promotes the formation of a dense heterogeneous microstructure characterized by extremely low porosity (1.2–2.5%) and record-low water absorption (less than 0.05%). These characteristics guarantee high dimensional stability of the frames during prolonged contact with process fluids and cutting fluids. The scanning electron microscopy (SEM) and (EDS) energy dispersive X-ray spectroscopy methods confirmed the dense packing and high degree of interaction of the polymer matrix with the crystalline phases of the filler. This condition of the interfacial boundaries guarantees stable stress transfer throughout the entire volume of the material, which minimizes the risk of local damage during operation. The study confirmed that the developed material has vibration damping properties 6–10 times more effective than gray cast iron, a critical factor in improving machining accuracy on modern metal-cutting machines. The scientific novelty of the study lies in its substantiation of the synergistic effect of the combined use of basalt fillers and silicon carbide to achieve the precision properties of a structural material. Its practical significance is confirmed by the possibility of producing large-scale parts by casting without the need for complex finishing, opening up new prospects for modernizing the machine tool industry. Full article

Background: Lipid peroxidation is a primary driver of biological membrane damage and mediates the relationship between environmental exposure and adverse health outcomes. Malondialdehyde (MDA) is a widely recognized biomarker for quantifying oxidative stress intensity. Despite numerous studies on oxidative stress and metal exposure, nonlinear relationships between physiological characteristics, serum metal profiles and MDA levels in pubertal children remain insufficiently studied. Methods: The study included 105 conditionally healthy children aged 12–14 years from urban and rural regions of Tatarstan, Russia. Serum MDA concentrations were determined spectrophotometrically using the thiobarbituric acid assay, while Zn, Cu, Fe, Sr and Pb concentrations were measured by atomic absorption spectrometry. A multilayer perceptron neural network was applied to model nonlinear relationships between MDA levels, environmental exposure indicators and morphophysiological characteristics. Because the original relational dataset contained partially replicated participant-derived relational structures, primary validation was performed using independently reconstructed datasets without repeated observations. Additional repeated cross-validation and SHAP-based feature importance analysis were performed. Results: Urban-residing children demonstrated significantly higher serum MDA levels than rural counterparts, independent of sex, with girls consistently showing higher values. Reduction of predictor dimensionality improved model generalization behaviour. Validation using independently reconstructed datasets without repeated observations demonstrated reproducible exploratory predictive behaviour of the reduced neural network model, with independently reconstructed validation datasets yielding mean R² values of 0.901 ± 0.052 and 0.914 ± 0.046, respectively. SHAP analysis demonstrated that zinc, copper and iron consistently represented the dominant contributors to the nonlinear model, although substantial variability in the relative ranking of zinc and copper was observed between validation datasets. Conclusions: The proposed neural network model demonstrated the ability to capture reproducible nonlinear relationships between oxidative stress markers and environmental exposure parameters in a limited biomedical dataset. The model should primarily be interpreted as an exploratory explanatory tool rather than an individual clinical prediction instrument. Because of the limited dataset size, partially reconstructed relational structure and exploratory study design, the findings require cautious interpretation and further external validation. Full article

Doxycycline (DOX) is a well-characterized antibiotic, and its pharmacokinetic behavior has recently attracted renewed scientific interest. Its absorption occurs mainly in the small intestine, while ions such as Fe³⁺ and Al³⁺ readily form complexes, particularly under acidic conditions, thereby reducing the fraction of free drug available for absorption. The present study provides a systematic investigation of how such interactions influence the dissolution and intestinal permeability of DOX. A dynamic in vitro protocol was implemented, incorporating an online transition from gastric to intestinal conditions in combination with Franz diffusion cells. This integrated system enables real-time monitoring of early DOX absorption-related processes, providing a more comprehensive understanding of potential pharmacokinetic interactions during its coadministration with iron or aluminum supplements. To ensure reliable quantification, a rapid, economical, and environmentally compatible HPLC-FLD method was developed and validated, employing a Hypersil Gold C18 column (50 mm × 4.6 mm, 5 μm; Thermo) and a mobile phase consisting of acetonitrile—20 mM NaH₂PO₄ (pH 2) 15:85 v/v. Overall, a practical and efficient framework was established for investigating factors that influence the bioavailability of doxycycline, supporting the broader evaluation of drug, excipient, and drug supplement interactions. Full article

The identification of the chemical species responsible for the anomalous near-ultraviolet (UV) opacity in the Venusian cloud for “unknown absorber” remains a paramount challenge in planetary science. This study presents a comprehensive quantum chemical investigation into a broad suite of candidate molecules, including isomers of thiosulfeno (S₂O₂), the hydroxysulfonyl radical (HSO₃), disulfur monoxide (S₂O), disulfur dichloride (S₂Cl₂), iron(III) chloride (FeCl₃), phosphine (PH₃), and structural isomers of polysulfur oxides (S₃O). Utilizing Time-Dependent Density Functional Theory (TD-DFT) at the CAM-B3LYP/def2-TZVPP level of theory, we systematically mapped electronic transitions across three distinct environmental phases: gas-phase (without solvent), supercritical CO₂, and concentrated H₂SO₄ aerosols. To establish confidence in the predicted results, our TD-DFT approach was rigorously benchmarked against high-level theoretical methods (CCSD(T), EOM-CCSD, and MRCI+Q) from recent literature. All these electronic transitions were modeled via the Solvation Model based on Density (SMD). Our results demonstrate a profound topological and environmental dependence on spectral signatures. Among the candidates, trans-OSSO (t-OSSO) emerged as the most viable near-UV absorber candidate, exhibiting a highly allowed π → π* transition at 379.37 nm (f = 0.1140) in H₂SO₄, providing a near-perfect alignment with the observed 365 nm planetary albedo drop. Conversely, the polysulfur oxide cis-S₃O was acknowledged as a primary visible-light chromophore, with an intense absorption at 436.31 nm (f = 0.1280) responsible for the characteristic yellow tint of the planet. Additionally, the photochemically maintained SSCl₂ isomer was identified as a critical broadband near-UV absorber. Species such as S₂O and planar S₃O were found to function as critical mid-UV shields (270–300 nm). This work establishes a multi-chromophore model of the Venusian atmosphere, where a chemically stratified network of sulfur-oxygen chains and chlorine-sulfur reservoirs, tuned by the acidic aerosol matrix, collectively governs radiative balance and atmospheric super-rotation of the planet. Furthermore, to account for massive continuum tailing into the visible region (>400 nm), we employed a semi-classical Reflection Principle approach to model 1D vibronic broadening. This analysis revealed that while standard solvent effects induce minor solvatochromic shifts, ground-state structural fluxionality in the OSSO isomers drives intense, symmetry-allowed transitions deep into the visible spectrum, an effect absent in structurally constrained or rigid control species. Full article

Effective absorption in the S-band usually requires relatively thick absorbing materials. However, growing application demands necessitate the development of high-performance materials with subwavelength thickness. This study presents a broadband absorbing metamaterial for the S-band, based on a novel structural design featuring a nested hexagonal metal resonant layer integrated with a carbonyl iron powder (CIP)/charcoal (CH)/epoxy resin (ER) composite slab. This structural innovation enables exceptional S-band absorption within a subwavelength thickness, effectively overcoming the inherent physical limitations of traditional materials. By combining the arch measurement method and simulations over the 2–18 GHz, we demonstrate that the metal resonant layer of the metamaterial plays a key role in controlling the electromagnetic field vector distribution. This work investigates the mechanism for enhancing S-band absorption in metamaterials through the redistribution of electromagnetic field vectors. Additionally, magnetic loss from CIP/CH/ER and dielectric loss from the resonators further enhance absorption performance. The designed absorbing metamaterial exhibits effective absorption at a thickness of only 2.25 mm, with a reflection loss (RL) below −10 dB from 2.2 to 3.8 GHz. Simultaneously, it can maintain a radar cross-section (RCS) below −10 dBm² in a wide-angle range of ±160°. Furthermore, a superhydrophobic coating with a contact angle of 152° was prepared for absorbing metamaterial. This coating allowed the metamaterial to preserve its microwave absorption performance while imparting self-cleaning capability. This study proposes a multifunctional absorbing metamaterial for efficient absorption in the S-band. Full article

To optimize the electromagnetic and mechanical properties, a resin-based coating with a bionic helical structure made by carbonyl iron fibers (CIF) was prepared by alternating spray and brushing with 0°/45°/90°. The morphologies of CIP and CIF were characterized by a scanning electron microscope (SEM). The electromagnetic parameters of CIP were measured in the frequency range of 2–18 GHz by the coaxial ring method, and microwave absorption properties of the coating were evaluated by reflection loss (RL). The mechanical properties of the coating with the bionic helical structure were investigated by the pull-off method. The effects of the CIP ratio, CIF content, and thickness on the microwave absorption were discussed, respectively. The results show that 6.5:3.5 is the optimal CIP-to-paraffin ratio with superior electromagnetic performance and RL. The coating with the triple helical structure, fiber content of 3 wt% and free of CIP (C4) exhibits optimal electromagnetic wave absorption performance with a minimum RL value of −10.66 dB and wide effective absorbing bandwidth (EAB) of 10.58 GHz at a thickness of 0.6 mm. Moreover, the adhesion strength of C4 reaches 13.52 MPa. The excellent absorption performance and mechanical properties of the resin-based coating with the bionic helical structure indicate that it has potential application value in the field of stealth materials. Full article

Iron deficiency (ID) is the most prevalent nutritional disorder worldwide, affecting diverse populations including children, women of reproductive age, older adults and patients with chronic conditions. Oral iron supplementation remains the cornerstone of treatment, together with management of the underlying causes. However, conventional ferrous and ferric salts are often associated with gastrointestinal side effects, poor adherence and limited efficacy, especially in inflammatory settings due to hepcidin-mediated absorption blockade. This review summarizes iron absorption physiology, limitations of traditional oral therapies, and the potential benefits of iron protein succinylate (IPS), a ferric complex bound to succinylated casein. IPS provides pH-dependent release and contains succinic acid, which may enhance absorption while reducing gastrointestinal adverse events. Clinical studies indicate that IPS achieves hematologic outcomes comparable or superior to standard oral salts, fewer gastrointestinal effects and better tolerability. These properties make IPS suitable for patients who do not tolerate or respond adequately to conventional therapy. Special attention is given to chronic inflammation, pregnancy, cancer, or gastrointestinal disorders, where oral iron often fails due to impaired absorption or poorer tolerance. Practical recommendations are included to optimize supplementation through dosing strategies and tailored approaches. Overall, IPS offers an effective, better-tolerated alternative to conventional oral iron therapy. Full article

Background/Objectives: Heart transplant recipients are particularly at risk for micronutrient deficiencies due to chronic immunosuppression, metabolic disorders, gastrointestinal absorption disorders, and increased postoperative demand. Despite a growing body of evidence suggesting their clinical relevance, the prevalence, characteristics, and consequences of these deficiencies remain poorly defined. The aim of this review was to assess of selected micronutrient deficiencies in personnel after heart vaccination and risk factors for their control. Methods: This scoping review was conducted in accordance with the Joanna Briggs Institute’s scope review methodology and presented in accordance with the PRISMA-ScR guidelines. A systematic search of PubMed, Scopus, EBSCO, Web of Science, Google Scholar, and Cochrane Library (January–February 2026) identified studies assessing micronutrient deficiencies in adult heart transplant recipients. Original publications, meta-analyses, and reviews available in full text in English were eligible for the review. Data extraction was carried out independently by two reviewers; using the PCC (Population–Concept–Context) model. Results: Of the 35 pre-identified records, 12 studies met the inclusion criteria. The most commonly reported deficiencies included iron, vitamin D, and B vitamins, and their incidence varied widely due to heterogeneous diagnostic criteria. Iron deficiency—both absolute and functional—was common and often associated with inflammation and impaired hepcidin regulation. Vitamin D deficiency persisted before and after transplantation and was associated with impaired bone health, inflammation, and a potentially increased risk of infection. Elevated homocysteine levels associated with low levels of folic acid and vitamin B6 have been identified as potential contributing factors to atherosclerotic and thrombotic complications. Limited evidence also points to deficiencies in iodine, zinc, and other trace elements. Conclusions: Micronutrient deficiencies are common among heart transplant recipients and can adversely affect immune system function, cardiovascular risk, and overall clinical outcomes. Routine evaluation and targeted correction of deficiencies should be considered in post-transplant care. Further prospective, multicenter, and interventional studies are needed to establish standardized diagnostic criteria and evidence-based supplementation strategies. Full article

Copper slag (CS) was considered a major by-product produced from the copper refining industry, which estimates about 2.2 to 3 tons generated during the production of every one ton of copper. At the same time, continuous dumping and improper disposal of this byproduct have led to serious environmental problems, especially due to the leaching of heavy metals into soil and water. This review carefully studies the potential of CS as a sustainable construction material through a clear distinction of its performance, especially when used as a fine aggregate and as a supplementary cementitious material (SCM). Due to the presence of higher content of iron and silica, higher hardness, and very low water absorption, it was found that CS helps in improving the density and durability of concrete. When used as a fine aggregate, CS enhances workability, strength, and durability at an optimum level of about 40%, mainly due to better particle packing and reduced pore connectivity. On the other hand, when used as an SCM, CS contributes to long-term strength through pozzolanic reactions and the formation of C–S–H gel, but its replacement level should be limited to about 20% to avoid loss of early-age strength caused by reduced alkalinity. In terms of durability, the use of CS can reduce water absorption by up to 60%, lower chloride penetration, and improve resistance to sulfate attack. Environmental Life Cycle Assessment studies show that CS can reduce global warming potential by about 12–19% and also decrease overall energy consumption. Statistical validation using multi-criteria decision analysis (MCDA) and separate regression modeling with an R² value of about 0.965, which supports these optimum replacement levels up to 40% for fine aggregate and 20% for cement, providing a good balance between strength, durability, environmental benefits, and cost. Overall, this review shows that CS is a valuable and multi-functional material that supports circular economy practices when used with a proper mix design based on specific applications. Full article

Since the synthesis of ferrocene in 1951, metallocenes have attracted attention, making the accurate prediction of their electronic structure and ionization energy crucial for understanding their photophysical and electrochemical behavior in materials and in biological systems. Here, we combined Density Functional Theory (DFT), Complete Active Space Self-Consistent Field (CASSCF), NEVPT2 (N-Electron Valence State Perturbation Theory) and Coupled Cluster approaches (CCSD, DLPNO-CCSD(T)) to study the electronic structure, ionization energies (IEs) and absorption spectra of metallocene and metallocenium complexes in the gas phase and in THF implicit solvent. DFT IEs agree closely with NEVPT2 and DLPNO-CCSD(T) values and with experiment values (deviations 0.02–0.3 eV). For CASSCF and NEVPT2, the minimal active space of the d electrons at six orbitals is not enough for the accurate prediction of the IEs, while an extended active space incorporating all 3d metal electrons plus four ligand valence electrons into 15 orbitals improves the calculated IE values. In solution, computed oxidation energies (OEs) in THF reproduce experimental values and follow the Fe > Ni > Co ordering. Substitution of metallocene complexes with chromophore units results in similar OEs. Overall, the substitution effects remain modest: the effect of substitution on OE values results in differences up to 0.2 eV. These results clarify the effect of the metal center on IE and OE values and UV–vis absorption behavior. Full article

Sandstone-type uranium deposits represent one of the most significant uranium deposit types in China, predominantly hosted in Meso-Cenozoic sedimentary basins in the northern part of the country. Due to characteristics such as deep burial of orebodies, fine grain size of ores, and strong heterogeneity, traditional geological logging methods have limitations in rapidly and accurately identifying alteration minerals and mineralization indicator information. Core spectral technology (wavelength range approximately 400–2500 nm), particularly short-wave infrared spectroscopy (SWIR, 1300–2500 nm), enables rapid, non-destructive, and quantitative extraction of alteration mineral information from drill cores. This provides robust technical support for reconstructing metallogenic environments, delineating oxidation–reduction zones, and prospecting and prediction in sandstone-type uranium deposits. This review systematically examines the spectral absorption characteristics and geological significance of key alteration minerals (e.g., clay minerals, carbonate minerals, iron oxides, and hydrocarbon substances) in sandstone-type uranium deposits. It elaborates on the current application status of core spectral technology in sandstone-type uranium exploration within typical basins in northern China, such as the Ordos, Songliao, Erlian, and Qaidam Basins. These applications include alteration mineral mapping, oxidation–reduction zone delineation, and metallogenic fluid tracing. Due to the unique characteristics of host rock lithology, alteration mineral assemblages, and fluid properties in sandstone-type uranium deposits, the application of this technology also faces certain challenges, such as difficulties in spectral interpretation and insufficient accuracy in quantitative inversion. Integrating this technique with multiple methods, including petrography and X-ray diffraction (XRD), will facilitate more effective applications in both metallogenic research and prospecting practices for sandstone-type uranium deposits in northern China. Full article