Search Results (2,264)

The structural, electronic, magnetic, and optical properties are explored in the G-type antiferromagnetic BiFeO${}_3$ system by replacing the Fe cation with transition metals to form the BiFe${}_{0.834}$X${}_{0.166}$O${}_3$ compound (where X = Mn, Co, or Ni) by using first-principles DFT+U and TDDFT calculations. All the optimized structures preserve the rhombohedral (R3c) space group, showing moderate changes in the FeO${}_6$ octahedral distortions, lattice parameters, and Fe–O–Fe bond angles. Pristine G-type antiferromagnetic (AFM-G) BiFeO${}_3$ is a typical semiconductor material with a calculated bandgap energy $E_g=1.99$ eV. However, the inclusion of Ni, Co, and Mn at the Fe site introduces additional 3d states near the Fermi level, causing metallic behavior in every case. The local density of states (LDOS), density of states (DOS), and total magnetization results show that the inclusion of Ni, Co, and Mn promotes a transition from antiferromagnetic (AFM) to ferrimagnetic behavior in the modified BiFe${}_{0.834}$X${}_{0.166}$O${}_3$ compositions. On the other hand, in the visible spectral region, the time-dependent density functional theory (TDDFT) revealed that the pristine material has refractive index $n\left(\omega \right)$ values between 2.8 and 3.6, showing that the presence of Co and Ni enhances the extinction and absorption coefficients in both visible and ultraviolet regions, whereas the inclusion of Mn produces less significant effects. These results demonstrate that controlled substitution at the Fe site with transition metals simultaneously modifies the structural, electronic, magnetic, and optical properties of the BiFeO${}_3$ system, offering promising potential for applications in electronic devices with multifunctional properties. Full article

Activated carbon has shown good catalytic performance in water treatment, but its wide application is limited by its high price. Activated coke exhibits functional groups and is low-cost. However, there is limited research on activated coke as a catalyst. In our previous study, powdered activated coke (PAC) exhibited good catalytic performance in NH₃-N treatment with ozonation. Increasing nitrogen selectivity is the key to harmless degradation of NH₃-N, which has received little attention. In this paper, manganese-loaded powdered coke (Mn–PAC) was prepared, aiming to further improve the nitrogen selectivity. Under the same conditions, the PAC/O₃ system achieved 92.16% NH₃-N removal and 49.46% nitrogen selectivity, while the Mn–PAC/O₃ system achieved almost 100% NH₃-N removal and 79.31% N₂ selectivity. When Mn–PAC was reused for the sixth time, the system achieved about 70% and 46% NH₃-N removal and N₂ selectivity, both of which were about 10% higher than those of PAC. Complex redox and synergistic interactions existed in the Mn–PAC/O₃ system. The Mn–PAC surface contains reactive sites such as C=C, C=O, π–π bonds, ArOH, and various MnO_x. These components collectively facilitate ozone decomposition into ·OH, ·O₂⁻, and ¹O₂. The ¹O₂ may play a significant role in converting NH₃-N to N₂. Full article

Stapedotomy is performed to restore ossicular chain sound transmission by inserting a piston prosthesis that couples the long process of the incus to the oval window, thereby addressing conductive hearing loss associated with otosclerosis. This study investigates the effects of crimping force, prosthesis material, and loop geometry on incus to optimize fixation while minimizing complications such as incudal necrosis. Finite element analyses were performed to quantify interface pressures and von Mises stresses for titanium prostheses with loop-band widths of 0.2, 0.3, and 0.5 mm under crimping forces of 300–500 mN and for polytetrafluoroethylene (PTFE) prostheses with loop outer diameters (OD) of 1.2, 1.4, and 1.8 mm. The analysis results showed that PTFE prostheses generated significantly lower interface pressures and stress compared to titanium. For PTFE prostheses, the equivalent von Mises stresses remained well below the critical threshold, with values ranging from 3.5 MPa up to peaks of approximately 43 MPa depending on the loop’s outer diameter. In contrast, titanium prostheses exhibited a marked dependency on crimping force and band width. At a force of 300 mN, stresses were modest (approximately 16–24 MPa). However, when increasing the force to 400 mN, stresses approached the critical threshold (up to approximately 53 MPa). With crimping forces of 500 mN, especially with band widths greater than 0.3 mm, stresses exceeded the cortical bone strength threshold (approximately 61–64 MPa), indicating an increased risk of mechanical overload and potential incudal necrosis. These findings highlight the importance, in a clinical context, of controlling the crimping force and selecting the material and geometry of the prosthesis to achieve secure coupling while preserving the incus’s structural integrity. Full article

This study aimed to investigate the effects of dietary manganese deficiency and compare the impact of manganese macroparticles (MnCO₃) and nanoparticles (Mn₂O₃NPs) on bone remodeling and metabolism. Twenty-seven male Wistar rats were divided into three groups (n = 9): control (standard MnCO₃, 65 mg Mn/kg), manganese-deficient, and Mn₂O₃NPs-supplemented (65 mg Mn/kg). After a 12-week feeding period, bone-related markers and gene expression were analyzed in the femur and blood. Mn-deficient rats showed reduced plasma levels of bone-specific alkaline phosphatase (BALP), tartrate-resistant acid phosphatase 5b (TRAP5b), interferon-β (IFN-β), RANKL glycoprotein, 1,25-dihydroxyvitamin D₃ (1,25-(OH)₂D₃), vitamin K₂, and collagen turnover markers (PINP, CTX-1, NTX). Femur levels of BALP, TRAP5b, interferon-γ (IFN-γ), osteonectin, calcitonin, PICP, PINP, and CTX-1 were also decreased. Replacing MnCO₃ with Mn₂O₃NPs increased IFN-γ but lowered IFN-β and 1,25-(OH)₂D₃ levels in plasma. This treatment also decreased the femur level of BALP and calcitonin, and the RANKL:OPG ratio, while increasing the expression level of Sp7 and Ctsk genes. To conclude, our results suggest that manganese deficiency is associated with suppressed bone turnover and altered mineral metabolism. Furthermore, replacing MnCO₃ with Mn₂O₃ nanoparticles did not yield the anticipated benefits for bone remodeling, as evidenced by the observed imbalances in osteogenic and resorptive markers, indicating a need for cautious evaluation of nanoparticle-based supplementation. Full article

The aim of this work is to study the correlations of the elemental composition in the “soil–grape–wine” chain to determine the regional origin of Chardonnay grapes and wine. Soil samples (n = 40) from five vineyards in the Anapa region, Russia, taken from eight different depths, grapes from these vineyards (n = 75), and wines obtained from these grapes (n = 5) were analyzed using inductively coupled plasma atomic emission spectrometry and inductively coupled plasma mass spectrometry. The mineralogical composition of the soils was determined using thermal and X-ray phase analysis. The mineralogical composition of vineyard soils mainly consists of calcite, quartz, nontronite, vermiculite, and muscovite. According to spectrometric analysis, the distribution of both the total content and the mobile forms of elements in soil profiles turned out to be similar. The content of Na, Ca, and Sr increased with increasing sampling depth, while the content of Co, Cu, Fe, Ni, Mn, Pb, and Zn decreased. Regardless of the area of cultivation, the predominant elements in grapes are K, Ca, Na, and Mg. It is established that the elemental profiles of grapes and wine are correlated. At the same time, during the winemaking process, a decrease in the concentration of most elements (Al, Ba, Ca, Cu, K, Mg, Mn, Ni, Rb, Sr, Ti, and Zn) is observed. It has been shown that the vine is able to accumulate not only mobile but also less bioavailable forms of metals from the soil (Cu, Fe, K, Rb, Ti, and Zn), while the migration of Ca and Na remains low (<7%). Using discriminant analysis, a model of grape identification based on the concentrations of Al, Li, Mn, Na, Pb, and Rb was developed. This model demonstrated a high accuracy (100% for training and test datasets) in grape classification by region, confirming that the elemental “fingerprint” is a reliable marker of terroir. Full article

Tool steels are critical for high-load applications, e.g., forging and metal-forming, where they face thermal cracking, fatigue, erosion, and wear. This study evaluates the impact of gas nitriding and S-phase PVD coatings on the mechanical and tribological properties of four tool steels: 40CrMnNiMo8-6-4, 60CrMoV18-5, X50CrMoV5-2, and X38CrMoV5-3. Samples were heat-treated (quenched and tempered at 600 °C), then gas-nitrided at 575 °C for 6 h with nitriding potentials (Kn) of 0.18, 0.79, or 2.18, or coated via reactive magnetron sputtering in Ar/N₂ or Ar/N₂/CH₄ atmospheres at 200 °C or 400 °C. Characterization involved XRD, LOM, FE-SEM, GDOES, Vickers hardness (HV0.1), and ball-on-disk wear testing with Al₂O₃_ counter-samples. Gas nitriding produced nitrogen diffusion layers (80–200 μm thick) and compound layers (ε-Fe_(2-3)N, γ’-Fe₄N) at higher Kn, increasing hardness by 80–100% (up to 1100 HV0.1 for steel X38CrMoV5-3). S-phase coatings (1.6–3.6 μm thick) formed expanded austenite with varying N content, achieving comparable hardness (up to 1100 HV0.1) in high-N₂ atmospheres, alongside substrate diffusion layers. Both types of treatment enhance load-bearing capacity, adhesion, and durability, offering superior wear resistance compared to conventional PVD coatings and addressing demands for extended tool life in industrial applications. Full article

No vaccines are licensed against enterotoxigenic Escherichia coli (ETEC), a leading diarrheal cause in children and travelers. ETEC adhesins and enterotoxins are the virulence determinants and become the primary targets in ETEC vaccine development. However, ETEC strains produce > 25 adhesins and two potent enterotoxins, particularly the poorly immunogenic heat-stable toxin (STa), greatly hindering ETEC vaccine development. To overcome these challenges, we developed a multiepitope-fusion-antigen (MEFA) platform. MEFA presented multiple adhesin epitopes on a backbone and generated a polyvalent adhesin immunogen, CFA/I/II/IV MEF. CFA/I/II/IV protected against the seven ETEC adhesins (CFA/I, CS1-CS6) associated with two-thirds of ETEC diarrheal cases. We further used toxoids as safe antigens and created a toxoid fusion, 3xSTa_N12S-mnLT_R192G/L211A. This antigen induced antibodies neutralizing the enterotoxicity of STa and heat-labile toxin (LT), which, alone or together, cause all ETEC diarrheal cases. By combining two polyvalent proteins, we developed a multivalent ETEC vaccine, MecVax, that protects against seven ETEC adhesins and two enterotoxins. MecVax is broadly immunogenic. MecVax prevents intestinal colonization by ETEC strains expressing any of the seven adhesins and protects against clinical diarrhea from ETEC strains producing LT or STa enterotoxin preclinically, becoming a broadly protective ETEC vaccine candidate against children’s diarrhea and travelers’ diarrhea. Full article

Background: Snipe eels (family Nemichthyidae) are a group of pelagic fishes with unique specializations; yet, species within this study are not well-studied due to a lack of molecular data. As typical mesopelagic-to-bathypelagic fishes, snipe eels exhibit extreme body elongation, reduced skeletal ossification, and highly specialized beak-like jaws that facilitate survival in deep-sea midwater environments. Methods: The complete mitochondrial genome of the deep-sea eel Nemichthys curvirostris (Anguilliformes: Nemichthyidae) was sequenced and annotated, representing the first mitogenomic resource for this species. The phylogenetic position of N. curvirostris was also explored. Results: The circular genome of N. curvirostris was determined to be 16,911 bp in length and contained 37 genes, including 13 protein-coding genes, 22 tRNAs, 2 rRNAs, and a single control region, with an overall A + T bias of 56.67%. The maximum-likelihood phylogeny inferred from concatenated mitochondrial protein-coding genes recovered a well-supported monophyletic Nemichthys clade, with N. curvirostris positioned as the sister taxon to N. scolopaceus. The genera Avocettina and Labichthys were recovered as sister taxa, and Nemichthys clustered within a broader clade alongside them. The COX1 haplotype phylogeny showed that the two public database sequences (HQ563894.1 and MN123435.1) appeared as long, isolated branches outside the main N. curvirostris lineage, with COX1 genetic distances from typical N. curvirostris haplotypes reaching 12–13%, far exceeding the expected range of intraspecific variation. Conclusions: This mitogenome provides a valuable molecular resource for phylogenetic, evolutionary, and population genetic studies of deep-sea Anguilliformes. Full article

Grokhovskyite, CuCrS₂, was observed in small sulfide inclusions (up to 50–80 µm) in Ni-rich iron (kamacite) of the Uakit iron meteorite (IIAB) in the Republic of Buryatia, Russia. The grain sizes of this mineral are usually less than 5 μm, and the biggest detected crystals are 10 × 5 μm in size. It is commonly associated with daubréelite, troilite, schreibersite, and, sometimes, with carlsbergite and uakitite. Within inclusions, the mineral forms elongated splintered crystals, or, rarely, needle-shaped grains in daubréelite. The grokhovskyite-containing associations in the Uakit meteorite seem to form due to high-temperature (>1000 °C) separation of Fe-Cr sulfide liquid, which is locally enriched in Cu, from Fe-Ni metal melt. Physical and optical properties of grokhovskyite are quite similar to those of synthetic CuCrS₂: yellow–brown and non-transparent phase with metallic luster; Mohs hardness ≈ 4; gray to light gray color with yellow tint in reflected light; weak to medium bireflectance, anisotropy, and pleochroism; density (calc.) = 4.559 g/cm³. Grokhovskyite is structurally related to the Cr-containing disulfide minerals with general formula Me⁺CrS₂ (where Me⁺ = Na, Cu, Ag), including caswellsilverite, NaCrS₂; schöllhornite, Na_0.3CrS₂·H₂O; and cronusite, Ca_0.2CrS₂·2H₂O. Structural data were obtained for one grokhovskyite crystal using the EBSD technique. Fitting of the EBSD patterns for a synthetic α-CuCrS₂ model (trigonal R3m; a = 3.4794(8) Å; c = 18.702(4) Å; V = 196.08(10) ų; Z = 3) resulted in the parameter MAD = 0.57–1.16° (good fit). Analytical data for grokhovskyite (n = 36, in wt.%) are as follows: Cu—32.97; Cr—27.65; Fe—3.69; Ni—0.16; S—35.71; Na, Zn, V, Mn, and Co—below detection limit (<0.005 wt.%). The empirical formula is (Cu_0.930Cr_0.952Fe_0.118Ni_0.005)_2.005S_1.995; however, different concentrations of Fe are indicated in two individual grains of grokhovskyite (0.09–0.17 apfu). Such variations may be explained by Fe incorporation in the grokhovskyite structure according to the scheme ^IVCu⁺ + ^VICr³⁺ → ^IVFe²⁺ + ^VIFe²⁺. The three main bands (near 110, 250, and 310 cm⁻¹), which are common of synthetic CuCrS₂, were observed in the Raman spectra of grokhovskyite. Full article

The floricultural value of Hydrangea macrophylla is significantly influenced by its distinctive blue flower coloration, which results from aluminum uptake and vacuolar complexation. However, commercial cultivation faces challenges in achieving consistent bluing while avoiding Al toxicity. This study investigated the effects of Al concentration (0–971.62 mg/L) and application period on six blue-modifiable cultivars. Optimal results were achieved with an Al₂(SO₄)₃·18H₂O concentration of 6 g/L applied from two weeks after pinching until bloom. This regimen successfully induced vibrant sepal bluing without impairing chlorophyll content or plant growth. Furthermore, it enhanced tissue concentration of essential nutrients, including N, K, Mg, Fe, Zn, Mn, Cu, B, and Co. This study proposes a robust technical and theoretical framework for optimizing Al application to ensure consistent sepal color, which provides technical support for commercial production. Full article

Bacground/Objectives: Cervical intraepithelial neoplasia (CIN) comprises a range of precancerous cervical lesions, and timely detection and intervention are essential to avert the development to invasive cervical cancer. Our previous study showed specific elemental alterations in the serum of patients with diagnosed CIN. In this study, we aimed to determine the levels of trace elements (Be, Cr, Mn, Co, Ni, Cu, Zn, Se, Cd, Tl, Pb, Rb, Sr, Mo, Th, and U) in more valuable materials, cervical tissue samples collected from patients diagnosed with CIN 2 and 3 (n = 60). Methods: The control group consisted of healthy, pathologically unaltered samples from the same patients (n = 60). The concentrations of all trace elements were determined using inductively coupled plasma–mass spectrometry (ICP-MS). Key demographic and clinical data were statistically analyzed in the context of trace element levels in cervical tissues. Results: We discovered that CIN 2 and CIN 3 tissues had significantly higher concentrations of essential trace elements Cr, Co, Se, and Mo, and toxic trace elements Be, Ni, and Cd compared to controls. The findings of this study highlight the differences in trace element concentrations in CIN tissue samples compared to controls. Conclusions: The presented results suggest the possible role of trace elements in the pathophysiological processes that lead to neoplasms in cervical tissues. The results provide initial and pivotal insight into the trace element concentrations in CIN tissues, which could aid further studies regarding cervical neoplasms and their pathogenesis. Full article

This work presents a multifactorial strategy for reusing waste thermoplastics and generating multifunctional filaments for additive manufacturing. Acrylonitrile–butadiene–styrene (ABS) waste and commercial poly(methyl methacrylate) (PMMA) were compounded with carbon black (CB), graphene (G), or graphene foam (GF) at different loadings and extruded into composite filaments. The aim is to couple filler-induced bulk modifications with atmospheric pressure plasma jet (APPJ) surface coatings of TiO₂ and graphene oxide (GO) to obtain waste-derived filaments with tunable morphology, wettability, and thermal stability for advanced 3D-printed architectures. The filaments were subsequently coated with TiO₂ and/or GO using an APPJ process, which tailored surface wettability and enabled the formation of photocatalytically relevant interfaces. Digital optical microscopy and SEM revealed that CB, G, and GF were reasonably well dispersed in both polymer matrices but induced distinct surface and cross-sectional morphologies, including a carbon-rich outer crust in ABS and filler-dependent porosity in PMMA. For ABS composites, static contact-angle measurements show that APPJ coatings broaden the apparent wettability window from ~60–80° for uncoated filaments to ~40–50° (TiO₂/GO) up to >90° (GO), corresponding to a ≈150% increase in contact-angle span. For PMMA/CB composites, TiO₂/GO coatings expand the accessible contact-angle range to ~15–125° while maintaining surface energies around 50 mN m⁻¹. TGA/DSC analyses confirm that the composites and coatings remain thermally stable within typical extrusion and APPJ processing ranges, with graphene showing only ≈3% mass loss over the explored temperature range, compared with ≈65% for CB and ≈10% for GF. Fused deposition modeling trials verify the printability and dimensional fidelity of ABS-based composite filaments, whereas PMMA composites were too brittle for reliable FDM printing. Overall, combining waste polymer reuse, tailored carbonaceous fillers, and APPJ TiO₂/GO coatings provides a versatile route to design surface-engineered filaments for applications such as photocatalysis, microfluidics, and soft robotics within a circular polymer manufacturing framework. Full article

One of the main uses of carob pods ‘algarroba’ (Neltuma spp.) is flour for direct human consumption in indigenous and rural populations of the Gran Chaco. The flour contains antioxidant compounds such as anthocyanins, flavonoids and alkaloids, the concentrations of which can vary according to environmental and genetic factors of the species. This ancestral food is an excellent nutritional alternative as a gluten-free ingredient with antioxidant potential for various culinary preparations. Minerals have essential functions in the human body, so a balanced diet is key to ensuring adequate intake. The composition of carob beans from the Paraguayan Chaco has been little explored in terms of their mineral nutrient content. The aim of this study was to determine the Fe, Cu, Zn and Mn content of carob meal from different species of Neltuma spp. From the Paraguayan Chaco. The mineral elements were determined by atomic absorption spectrometry using official AOAC (2000) methods. Of the samples analysed, N. ruscifolia carob flour had the highest content of Zn (2.2 ± 0.8 mg/100 g), Mn (1.6 ± 0.1 mg/100 g) and Cu (1.5 ± 0.4 mg/100 g). N. nigra and N. alba flour showed higher Fe contents (4 ± 2 and 3 ± 2 mg/100 g, respectively). Consumption of 100 g of P. ruscifolia and P. nigra meal would cover up to 100% of the Recommended Daily Intake (RDI) for Cu and 55–72% of the RDI for Mn. This implies that carob-based foods from Paraguayan Chaco species could have a protective role against oxidative stress if incorporated as functional foods, as well as representing a natural and bioavailable source of antioxidant minerals, which is especially valuable in diets of vulnerable populations with deficiencies or increased requirements, such as in pregnancy, ageing, or chronic diseases. Full article

The sustainable operation of hydroponic systems depends on maintaining the chemical stability of circulating nutrient solutions and preventing the accumulation of toxic compounds. The accumulation of phytotoxic ammonium, heavy metals, and organic metabolites in recirculating nutrient solutions remains one of the key challenges limiting the efficiency, sustainability, and scalability of hydroponic cultivation. This review provides a comprehensive comparative analysis of zeolites, activated carbons (ACs), and their functionalized and composite forms as key sorbents for nutrient management, contaminant removal, and environmental safety in hydroponic cultivation. Natural zeolites, with their well-defined crystalline structure and high ion-exchange selectivity toward ammonium and heavy metal cations, enable effective NH₄⁺/K⁺ balance regulation and phytotoxicity mitigation. ACs, characterized by high specific surface area and tunable surface chemistry, complement zeolites by offering extensive adsorption capacity for organic compounds, root exudates, and pesticide residues, thereby extending the operational lifespan of nutrient solutions and improving overall system performance. Further advancements include the integration of zeolites and ACs with two-dimensional (graphene, g-C₃N₄) and three-dimensional (MOF, COF) frameworks, yielding multifunctional materials that combine adsorption, ion exchange, photocatalysis, and nutrient regulation. Transition-metal modification, particularly with Fe, Mn, Cu, Ni, and Co, introduces redox-active centers that enhance sorption, catalysis, and phosphate stabilization. The comparative synthesis reveals that the combined application of zeolite- and carbon-based composites offers a synergistic strategy for developing adaptive and low-waste hydroponic systems. From a techno-economic and environmental standpoint, the judicious application of these materials paves the way for more resilient, efficient, and circular hydroponic systems, reducing fertilizer and water consumption, lowering contaminant discharge, and enhancing food security. This systematic review was conducted according to the PRISMA 2020 guidelines. Relevant studies were identified through Scopus, Web of Science, and Google Scholar databases using specific inclusion and exclusion criteria. Full article

Background: Conventional insulin injections cannot mimic physiological pancreatic function and often lead to dangerous hypoglycemic events that glucose-responsive systems aim to prevent. Glucose-responsive microneedles (MNs) offer a promising closed-loop alternative. We developed an enzyme-free, glucose-responsive MN patch composed of a PVA/Dextran hydrogel dynamically crosslinked with borax, and evaluated its performance, biosafety, and in vivo efficacy. Methods: MNs were fabricated from PVA/Dextran via micromolding and crosslinked with borax. The formulation was systematically optimized based on mechanical properties and glucose-responsive release kinetics. Physicochemical properties, biosafety (cytotoxicity, skin barrier recovery, boron leaching), and in vivo efficacy in a type 1 diabetic mouse model were evaluated in comparison to a subcutaneous (SC) insulin injection. Results: The optimized MNs showed robust mechanics (per-needle fracture force approximately 1.0 N) for reliable skin penetration. The system demonstrated clear glucose sensitivity, with a release flux ratio ≥1.5 between hyperglycemic (e.g., 400 mg·dL⁻¹) and normoglycemic (100 mg·dL⁻¹) conditions and exhibited excellent reversibility under alternating glucose levels. The patch was highly biocompatible, with >95% cell viability, the only transient skin barrier disruption that fully recovered within 24 h, and had low boron release from patches in vitro. In vivo, the optimized sI-MN patch demonstrated a sustained, glucose-responsive release profile, maintaining blood glucose in diabetic mice near 100 mg·dL⁻¹ for approximately 8 h. This pharmacokinetic profile contrasts markedly with the rapid hypoglycemic nadir and rebound hyperglycemia observed with a standard subcutaneous insulin bolus, highlighting the patch’s potential for mitigating hypoglycemia. Conclusions: The enzyme-free PVA/Dextran/borax MN patch enables autonomous, glucose-responsive insulin delivery. It provides more stable and safer glycemic control than conventional injections by mitigating the risk of hypoglycemia. By mitigating the hypoglycemic risk associated with bolus injections, this systematically optimized platform represents a potential step toward a safer, patient-friendly diabetes therapy, though significant challenges in duration and dose scaling remain. Full article