Search Results (357)

The present review paper focuses on the peculiar environmental and health implications of fibrous amphibole “fluoro-edenite”, a new mineral first reported in Biancavilla (Etna Mount, Sicily, Italy). Its presence has been linked to an unusually high incidence of malignant pleural mesothelioma, as seen from national surveys during 1988–1997, marking the first case study of natural occurrence of fibrous amphibole in a volcanic context. Despite remediation efforts since the cessation of quarrying activities at the “Il Calvario” quarry, the risk of fiber exposure may extend beyond urban areas to surrounding soils and volcanic formation, not fully characterized yet. This review synthesizes relevant existing literature on mineralogical and chemical features of fluoro-edenite, while also enriching current understanding with new observations from optical microscopy, stereomicroscopy, and Scanning Electron Microscopy (SEM). Our analyses reveal the presence of fluoro-edenite amphibole not only in the altered samples but, significantly, within the massive rock samples. This finding expands its known distribution and offers initial consideration on public health implications related to massive lava rock, which crops out. This study highlights the importance of ongoing monitoring, detailed geological surveys, and further research into fiber occurrences and distribution in the volcanic systems, of which Mt. Etna represents the first case of natural occurrences, in order to fully assess their impact on public health. Full article

Atrazine (ATZ), a typical triazine herbicide with a long half-life and recalcitrant biodegradation, contaminates water and soil, necessitating efficient removal technologies. Conventional adsorbents have limited capacity and stability, while sesame straw-derived biochar realizes agricultural waste recycling and provides an efficient, economical, and eco-friendly adsorbent. Sepiolite, a natural mineral with a unique fibrous structure and a high specific surface area, has attracted widespread attention. Therefore, in this work, the agricultural waste of sesame hulls and sepiolite were used as precursors to prepare a composite material of sesame hull biochar/sepiolite (KNPB) through co-mixing heat treatment, followed by sodium hydroxide activation and pyrolysis. The results showed that, under the conditions of an adsorbent dosage of 3 g/L, pH of 6.8, and an adsorption time of 360 min, the removal rate of 3 mg/L ATZ by KNPB was 89.14%. Reusability experiments further demonstrated that KNPB has the potential for practical application in water treatment. Additionally, by integrating adsorption kinetics and isotherm analysis with a suite of characterization results from BET, FTIR, and XPS, the adsorption mechanism of KNPB for ATZ was further clarified to be primarily based on pore-filling, π–π interactions, and hydrogen bonding. This study not only provides a new idea for the resource utilization of waste sesame straw, but also provides scientific guidance for the solution of atrazine pollution, which has important environmental and economic significance. Full article

Ethyl butyrate is a typical flavor ester with pineapple-banana scents, but the poor yield from natural fruits limits its feasibility in food and fragrance industries. In this study, dendritic fibrous nano-silica (DFNS) was hydrophobically modified with octyl groups (DFNS-C₈) to immobilize Candida antarctica lipase B (CALB) for solvent-free esterification of ethyl butyrate. The immobilized lipase CALB@DFNS-C₈, with the enzyme loading of 354.6 mg/g and the enzyme activity of 0.064 U/mg protein, achieved 96.0% ethyl butyrate conversion under the optimum reaction conditions where the molar ratio of butyric acid to ethanol was 1:3, with a reaction temperature and time of 40 °C and 4 h. Under the solvent-free catalytic reactions, CALB@DFNS-C₈ presented the maximum catalytic efficiency of 35.1 mmol/g/h and retained 89% initial activity after ten reuse cycles. In addition, the immobilized lipase can efficiently catalyze the synthesis of various flavor esters (such as butyl acetate, hexyl acetate, butyl butyrate, etc.) and exhibits excellent thermostability and solvent tolerance. A molecular docking simulation reveals that the hydrophobic cavity around the catalytic triad stabilizes the acyl intermediate and ensures the precise orientation of both acid and alcohol substrates. This work provides new insights into the sustainable production of flavor esters using highly active and recyclable immobilized lipases through rational carrier hydrophobization and structural confinement design. Full article

Biocomposites based on natural fibres represent a promising solution for the circular economy. The aim of this study was to develop and characterise a biodegradable composite based on sheep wool from herds raised in the Kyrgyz Republic and polylactide (PLA 4032D). Composite samples with a wool–PLA ratio of 50:50 were fabricated by thermoforming at a temperature of 168 °C for 30 s (n = 10). Mechanical properties tests were performed (PN-EN ISO 604—compression tests), for impact resistance (Charpy method), differential scanning calorimetry (DSC), and measurements of density and thermal conductivity. Biodegradation samples were subjected to enriched soil conditions for 6 weeks in two variants (with and without irrigation). The results showed that the addition of sheep wool to the PLA matrix significantly increased compressive strength (23.56 ± 5.23 MPa) and impact energy absorption (226.2 ± 23.8 kJ/m²) compared to neat PLA. After biodegradation, a 59% reduction in compressive strength was observed while maintaining an increase in fracture energy, suggesting a change in the failure mechanism. The density (0.27 ± 0.02 g/cm³) and the thermal conductivity (0.127 W/m·K) comparable to polymer foams indicate potential for thermal insulation applications. Microscopy and DSC analysis confirmed complete biodegradation under soil conditions. The developed biocomposite from Kyrgyz sheep wool demonstrates the potential for valorisation of local fibrous waste for biodegradable materials with functional insulation properties. Full article

Electrospun fibrous scaffolds based on cellulose acetate (CA), polycaprolactone (PCL), and poly (L-lactic acid) (PLLA) are versatile materials with applications spanning diverse fields, but in their pristine form, they typically lack significant inherent antibacterial properties. To address this limitation and expand their utility, this study explored the incorporation of xylitol, a natural antibacterial sugar alcohol, into these polymer matrices to enhance their physicochemical and antimicrobial properties. Electrospinning was employed to fabricate pristine and xylitol-loaded scaffolds with varying xylitol concentrations. Morphological analysis revealed polymer-dependent changes in fiber diameter and porosity. Mechanical testing assessed the impact of xylitol on tensile properties, while thermal analysis investigated alterations in melting temperature and crystallinity. The antibacterial efficacy against Staphylococcus aureus and Escherichia coli was evaluated using WST assay and live/dead staining. Notably, xylitol significantly enhanced the antibacterial activity against both bacterial species, with a more pronounced and rapid effect observed against S. aureus. The tailored scaffold properties and imparted antimicrobial characteristics highlight the potential of these xylitol-modified electrospun materials: they are easily produced, low-cost, and appropriate for a range of applications (dental applications, filters, masks, wound dressing, and packaging) where preventing bacterial contamination is crucial. Full article

The growing demand for sustainable alternatives to animal and synthetic leathers has accelerated interest in mycelium-based materials as an eco-friendly solution for the fashion industry. This study explores the potential of mushroom mycelium to create leather-like materials that align with circular fashion principles. Five species of edible and medicinal mushrooms were cultivated on sawdust substrates and evaluated for their growth performance, physical properties, and suitability as leather substitutes. Growth analysis revealed distinct species-specific behaviors: Cubamyces flavidus and Lentinus squarrosulus exhibited rapid colonization, achieving full substrate coverage within five days and forming dense mycelial networks at 14 days. In contrast, despite growing more slowly, Sanghuangporus vaninii and Ganoderma gibbosum formed thicker, more compact mats that might be suitable for strong leather-like materials. Visual and structural assessments showed diverse textures, colors, and hyphal architectures resembling natural leather. Physical characterization revealed shrinkage ranging from 13.17% to 24.09%, higher than for cow tanned leather (>5%) and PU microfiber (0.1–1.2%), suggesting a need for stabilization treatments. Apparent densities ranged from 0.13 g/cm³ to 0.30 g/cm³, lower than those of cow leather (0.49 g/cm³) and PU leather (0.38 g/cm³), highlighting species-specific hyphal structures that influence flexibility, porosity, and strength. SEM imaging confirmed the presence of interwoven hyphal mats resembling the fibrous architecture of natural leather, with S. vaninii showing the most uniform and continuous structure. Water absorption was significantly higher in mycelium sheets, consistent with their microporous nature, though S. vaninii showed the lowest uptake, reflecting possible natural water absorption. Thermogravimetric analysis revealed three-stage degradation profiles, with S. vaninii and G. gibbosum retaining >35% mass at 400 °C, indicating strong thermal stability for processing techniques such as hot pressing and finishing. Overall, the results demonstrate mycelium-based leathers as a biodegradable, low-impact alternative that can replicate the visual and functional characteristics of traditional leather, with opportunities for further improvement in substrate optimization, eco-tanning, surface coating, and scalable production toward a sustainable fashion future. Full article

Root morphology and uptake capacity are increasingly investigated as indicators of crop performance, yet their characterization remains challenging in laboratory. Soil or sand are opaque to most forms of radiation, while transparent medium fails to provide soil-relevant characteristics. Transparent soil (TS) is specifically designed to support root growth in the presence of air, water, and nutrients, enabling in situ root phenotyping. An indoor experiment was conducted, involving three growth mediums (natural soil, TS, hydroponics), two fibrous-root crop species (wheat, maize) and two taproot crop species (cotton, soybean), to evaluate the impact of TS on root morphology and water and nitrogen uptake of crops with different root types. Results showed that, compared with the average difference between hydroponics and natural soil, the average difference in root morphology and water and nitrogen uptake of maize between TS and natural soil was significantly decreased, as well as for cotton, soybeans, and wheat in turn. It was concluded that compared to those developed in hydroponics, the root developed in TS was significantly more similar to those developed in natural soil. Yet such similarity varied across crop species, with no clear correlation to root types. These findings provide a theoretical foundation for promoting the application of TS. Full article

Keratin is a fibrous structural protein found in various natural materials such as hair, feathers, and nails. Its high stability and cross-linked structure make it resistant to degradation by common proteases, leading to the accumulation of keratinous waste in various industries. In this study, we developed and validated an effective bioinformatics-driven strategy for mining novel keratinase genes from the Esmatlas (ESM Metagenomic Atlas) macrogenomic database. Two candidate genes, ker820 and ker907, were identified through sequence alignment, structural modeling, and phylogenetic analysis, and were subsequently heterologously expressed in Escherichia coli Rosetta (DE3) with the assistance of a solubility-enhancing chaperone system. Both enzymes belong to the Peptidase S8 family. Enzymatic characterization revealed that GST-tagged ker820 and ker907 exhibited strong keratinolytic activity, with optimal conditions at pH 9.0 and temperatures of 60 °C and 50 °C, respectively. Both enzymes showed significant degradation of feather and cat-hair keratin. Kinetic analysis showed favorable catalytic parameters, including $K_m$ values of 9.81 mg/mL (ker820) and 5.25 mg/mL (ker907), and $V_{max}$ values of 120.99 U/mg (ker820) and 89.52 U/mg (ker907). Stability tests indicated that GST-ker820 retained 70% activity at 60 °C for 120 min, while both enzymes remained stable at 4 °C for up to 10 days. These results demonstrate the high catalytic capacity, thermal stability, and substrate specificity of the enzymes, supporting their classification as active keratinases. This study introduces a promising strategy for efficiently discovering novel functional enzymes using an integrated computational and experimental approach. Beyond keratinases, this methodology could be extended to screen for enzymes with potential applications in environmental remediation. Full article

Background/Objectives: Skin wounds interrupt the natural anatomy and function of the skin. The body passes through four physiological phases to repair wounds after injury. Since the fibers are more closely related to the extracellular matrix structure, they can be used as scaffolds to accelerate wound closure. Shikonin is a botanical herbal remedy used as an anti-inflammatory agent and for its wound-healing characteristics. Cresols are known for their bactericidal and fungicidal properties, which promote their utilization as a disinfectant in soap. Therefore, this study aimed to formulate shikonin and cresol-loaded nanofibers for a dual wound-healing and antibacterial wound dressing in vitro. Methods: This study demonstrated the effectiveness of the drug-loaded nanofibers against diverse Gram-positive and Gram-negative bacteria using the minimum inhibitory concentration (MIC) and zone of inhibition assays. Results: Scanning electron microscopy images showed successful formulation of shikonin/cresol fibers with an average diameter of 772 ± 152 nm. The encapsulation efficiency and drug loading for the dual drug-loaded fibers were 44 ± 1% and 25 ± 1 µg/mg, respectively, for shikonin, and 38 ± 1% and 21 ± 0.5 µg/mg, respectively, for cresol, with a full release of both drugs achieved after 180 min. The combination of both compounds exhibited a safe concentration of ≤6 µg/mL, with cell viability of >50% in human dermal fibroblasts (HFF-1) after 24 h. The MIC results indicated that the combination was efficient as an antibacterial agent against Gram-positive bacteria at a safe concentration. The shikonin/cresol-loaded fibrous system showed an inhibition zone close to that of the control drugs, suggesting that the drugs have retained their antibacterial activity after electrospinning. Conclusions: This dual drug-loaded fiber system showed a high potential as an antibacterial wound dressing for skin infection injuries. However, in vivo studies are required to assess the safety and efficacy in an animal model of the dual drug-loaded fiber system. Full article

Asbestos, consisting of six natural mineral fibrous silicate phases, was widely utilized in industrial development during the 20th century and has left a global legacy of health, environmental, and regulatory challenges. Its remarkable properties (e.g., heat resistance, sound absorption, and tensile strength) made it a useful material in numerous applications. However, scientific research revealed its serious health risks in the early 1900s, with growing evidence during the 1960s, and nowadays its role in the development of different diseases (e.g., respiratory diseases, such as lung cancer, mesothelioma, and asbestosis) is well defined. Mapping this complex history requires integrating heterogeneous and often inconsistent information from nearly 200 countries. In this study, we tested the use of generative artificial intelligence (AI) tools as exploratory and comparative instruments to support the collection of asbestos-related data worldwide. Using Google Gemini (version 2.5 flash) and OpenAI ChatGPT (GPT-4-turbo variant), we gathered historical, medical, and regulatory information and then systematically verified and contextualized it with expert analysis. This dual approach allowed us to assess both the global asbestos situation and the reliability, advantages, and limitations of AI-assisted research. Our results highlight how AI can accelerate data collection and provide useful first drafts while underscoring the necessity of human expertise for validation, interpretation, and critical integration. This study, therefore, contributes a dual perspective: a comprehensive overview of the asbestos legacy across countries and a methodological reflection on the opportunities and pitfalls of employing AI in geoscientific and environmental research. Full article

This study investigates the air filtration capabilities of fibrous membranes fabricated via electrospinning, with a focus on optimizing processing parameters. Specifically, Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), a well-characterized biodegradable polyester, was electrospun to produce membranes exhibiting precisely controlled surface microstructures. The optimal fiber morphology was attained under conditions of a 20 kV applied electric field, a solution flow rate of 0.5 mL·h⁻¹, a polymer concentration of 13 wt.%, and a needle inner diameter of 0.21 mm. The microstructural features of the electrospun PHBV membranes were characterized using scanning electron microscopy (SEM). Complementary analysis via ¹³C nuclear magnetic resonance (NMR) spectroscopy confirmed that the membranes comprised pure 3-hydroxyvalerate (3HV) copolymerized with 3-hydroxybutyrate (3HB) terminal units, with 3HV mole fractions ranging from 17% to 50%. The incorporation of different molar percentages of 3HV in PHBV membrane significantly enhances its durability, as evidenced by Ball Burst Strength (BBS) measurements, with an elongation at burst that is 65–86% greater than that of ASTM F2100 level 3 mask. The nanofibrous membranes exhibited a controlled pore size distribution, indicating their potential suitability for air filtration applications. Particle filtration efficiency (PFE) assessments under standard atmospheric pressure conditions showed that the optimized electrospun PHBV membranes achieved filtration efficiencies exceeding 98%. Additionally, the influence of 3HV content on biodegradation behavior was evaluated through soil burial tests conducted over 90 days. Results indicated that membranes with lower 3HV content (17 mol.%) experienced the greatest weight loss, suggesting accelerated degradation in natural soil environments. Full article

In response to environmental pressures and the growing demand for sustainable materials, this study investigates the use of lignocellulosic fillers derived from sorghum (Sorghum bicolor L. Moench) biomass, specifically stems and leaves, as reinforcements in biodegradable polylactic acid (PLA) composites. The aim was to assess the effect of filler type and content (5, 10, and 15 wt.%) on the physicochemical properties of the composites. Sorghum was manually harvested in Greater Poland, separated, dried, milled, and fractionated to particles <0.25 mm. Composites were produced via extrusion and injection molding, followed by characterization using differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), thermogravimetric analysis (TGA), tensile and impact testing, density measurements, optical microscopy, and scanning electron microscopy (SEM). Results showed that stem-based fillers provided a better balance between stiffness and ductility, along with improved dispersion and interfacial adhesion. In contrast, leaf-based fillers led to higher stiffness but greater brittleness and agglomeration. All composites exhibited decreased impact strength and thermal stability compared to neat PLA, with the extent of these decreases depending on the filler type and loading. The study highlights the potential of sorghum stems as a viable, renewable reinforcement in biopolymer composites, aligning with circular economy and bioeconomy strategies. Full article

(1) Background: The extracellular matrix (ECM) is a natural scaffold for cells, creating a three-dimensional architecture composed of fibrous proteins (mainly collagen) and proteoglycans, which are synthesized by resident cells. In this study, a physiological hypoxic environment was utilized to enhance ECM production by human mesenchymal stem cells (hMSCs), a process relevant to tissue engineering and regenerative medicine. (2) Methods: hMSCs were treated with deferoxamine (DFO), a pharmaceutical hypoxia-mimetic agent that induces cellular responses similar to low-oxygen conditions through stabilization of hypoxia inducible factor-1α (HIF-1α). The time points 0 h 24 h, 3 h 24 h, and 24 h 24 h refer to DFO being added immediately after cell seeding (before cells adhesion), 3 h after cell seeding (during initial cells attachment), and 24 h after cell seeding (after focal adhesions formation and actin organization), respectively, to evaluate the influence of cell adhesion on ECM deposition. hMSCs incubated in culture media were subsequently exposed to DFO for 24 h. Samples were then subjected to cell viability tests, scanning electron microscopy (SEM), atomic force microscopy (AFM) and laser scanning confocal microscopy (CLSM) assessments. (3) Results: Viability tests indicated that DFO concentrations in the range of 0–300 µM were non-toxic over 24 h. The presence of collagen fibers in the DFO-derived ECM was confirmed with anti-collagen antibodies under CLSM. Increased ECM secretion was observed under the following conditions: 3 μM DFO (24 h 24 h), 100 μM DFO (0 h 24 h) and 300 μM DFO (3 h 24 h). SEM and AFM images revealed the morphology of various stages of collagen formation with both collagen fibrils and fibers identified. (4) Conclusions: Our preliminary study demonstrated enhanced ECM secretion by hMSC treated with DFO at concentrations of 3, 100, and 300 µM within a short cultivation period of 24–48 h without significant affecting cell viability. By mimicking physiological processes, it may be possible to stimulate endogenous tissue regeneration, for example, at an injury site. Full article

Shilajit, a natural herbo-mineral compound with potent antioxidant, anti-inflammatory, and osteogenic properties, has been traditionally used to promote tissue repair. However, limited experimental data exist on its localized application in bone regeneration. This study aimed to evaluate the combined effect of Shilajit and bovine-derived xenograft on bone healing in a rat tibial defect model. Twenty-eight male Sprague–Dawley rats were randomly assigned to four groups (n = 7): Control (defect left to heal spontaneously), Graft-only, Graft + Shilajit 150 mg/kg, and Graft + Shilajit 250 mg/kg. Standardized 3 mm tibial defects were created and filled with xenograft in all groups except the Control. Shilajit was administered intraperitoneally on days 0–3 postoperatively. After 4 weeks, serum total oxidant status (TOS), total antioxidant status (TAS), and TNF-α levels were measured. Tibial specimens underwent histopathological, histomorphometric, and TNF-α immunohistochemical analysis. High-dose Shilajit significantly increased TAS and reduced TOS compared with the Control and Graft-only groups (p < 0.001). Median TNF-α concentrations decreased in a dose-dependent manner, with the lowest values in the high-dose group (15.7 [14.3–17.1] pg/mL, p < 0.001). Histomorphometry revealed the highest new bone area percentage (78.1% [74.9–81.2]) and lowest fibrous tissue content (9.8% [8.1–11.6]) in the high-dose group. Immunohistochemistry confirmed marked suppression of TNF-α expression in Shilajit-treated groups, particularly at high doses. The combination of Shilajit and bovine-derived xenograft significantly enhanced bone regeneration in a dose-dependent manner, likely through antioxidative, anti-inflammatory, and osteogenic mechanisms. These findings suggest that Shilajit may serve as a promising adjunct in bone grafting procedures. Full article

The novel fibrous composites of Al₆₁Cu₂₇Fe₁₂ alloy with a single-crystalline matrix and quasi-crystal phase fraction obtained in situ by directional solidification by the Bridgman method were studied to characterize the voids and their role in composites cracking. The voids were analyzed using light-optical and scanning electron microscopy to study their nature before and after uniaxial tensile tests. Tension tests were performed on plate-like samples up to rupture. The tensile fracture surfaces were also observed and analyzed. The single-crystallinity and crystalographic parameters of composites were studied using the X-ray Laue diffraction method. It was stated that such new type of composite is characterized by a relatively high void content with a ratio of approximately 2.6%. The composite’s cracking is initiated at voids and progress through the voids and stair steps in the matrix and the reinforcing fibers. Full article