Search Results (3,153)

Modulating the electronic structure and surface properties of graphitic carbon nitride (g-C₃N₄) by chemically phosphorus doping is an effective strategy for improving its photocatalytic performance. However, in order to benefit from practical applications, the cost-effectiveness, efficiency, and optimization of the doping level need to be investigated further. Herein, we report a structural doping of P into g-C₃N₄ by in situ polymerization of the mixture of dicyandiamide (DCDA) and phosphorus pentoxide (P₂O₅). As an alternative to previous studies that used complex organic phosphorus precursors or post-treatment strategies, this work proposed a one-pot thermal polycondensation method that is low-cost, scalable, and enables controlled phosphorus substitutions at carbon sites of the g-C₃N₄ heptazine structure. Most of the structural features of g-C₃N₄ were well retained after doping, but the electronic structures and light harvesting capacity had been effectively altered, which provided not only a much better charge separation but also an improvement in photocatalytic activity toward H₂ evolution under irradiation of a simulated sunlight. The optimized sample with P-doping content of 9.35 at.% (0.5PGCN) exhibited an excellent photocatalytic performance toward H₂ evolution, which is over 5 times higher than that of bulk g-C₃N₄. This work demonstrates a facile one-step in situ route for producing high-yield photocatalysts using low-cost commercial precursors, offering practical starting materials for studies in solar cells, polymer batteries, and photocatalytic applications. Full article

The irradiation of atomic oxygen (AO) severely restricts the application of polymeric lubricating coatings in low Earth orbit (LEO). Herein, octa- and mono-amino polyhedral oligomeric silsesquioxanes (POSSs) were chemically bonded onto polyimide/molybdenum disulfide (PI/MoS₂) composite coatings with a gradient structure based on Si density. The gradient coatings presented better wear resistance under different loads; notably, the wear rate decreased by 83.5%. Additionally, the effects of AO exposure on the surface morphologies, chemical structure, and tribological properties of the gradient coatings were investigated in detail. The results indicated that the mass loss and wear rates under AO irradiation decreased significantly, which can be attributed to the passivated network-like SiO₂ layer that covered the coating surface after AO irradiation. As a result, the addition of POSS significantly improved the tribological properties and AO resistance. Full article

Background/Objectives: The clinical application of CAD/CAM restorative materials continues to evolve due to increasing demand for aesthetic, durable, and minimally invasive indirect restorations. Hybrid nanoceramics, such as Grandio disc (VOCO GmbH, Cuxhaven, Germany), are increasingly used in indirect restorative dentistry due to their favourable combination of mechanical strength, polishability, wear resistance, and bonding potential. One challenge associated with adhesive protocols for CAD/CAM materials lies in achieving durable bonds with resin cements. Extensive post-polymerization during fabrication reduces the number of unreacted monomers available for chemical interaction, thereby limiting the effectiveness of traditional adhesive strategies and necessitating specific surface conditioning approaches. This study aimed to evaluate, in a preliminary, non-inferential manner, the influence of several combined conditioning protocols on surface micromorphology, elemental composition, and descriptive SBS trends of a CAD/CAM hybrid nanoceramic. This work was designed as a preliminary pilot feasibility study. Due to the limited number of specimens (two discs per protocol, each providing two independent enamel bonding measurements), all bond strength outcomes were interpreted descriptively, without inferential statistical testing. This in vitro study investigated the effects of various surface conditioning protocols on the adhesive performance of CAD/CAM hybrid nanoceramics (Grandio disc, VOCO GmbH, Cuxhaven, Germany) to dental enamel. Hydrofluoric acid (HF) etching was performed to improve adhesion to indirect resin-based materials using two commercially available gels: 9.5% Porcelain Etchant (Bisco, Inc., Schaumburg, IL, USA) and 4.5% IPS Ceramic Etching Gel (Ivoclar Vivadent, Schaan, Liechtenstein), in combination with airborne-particle abrasion (APA), silanization, and universal adhesive application. HF may selectively dissolve the inorganic phase, while APA increases surface texture and micromechanical retention. However, existing literature reports inconsistent results regarding the optimal conditioning method for hybrid composites and nanoceramics, and the relationship between micromorphology, elemental surface changes, and adhesion remains insufficiently clarified. Methods: A total of ten composite specimens were subjected to five conditioning protocols combining airborne-particle abrasion with varying hydrofluoric acid (HF) concentrations and etching times. Bonding was performed using a dual-cure resin cement (BiFix QM) and evaluated by shear bond strength (SBS) testing. Surface morphology was examined through environmental scanning electron microscopy (ESEM), and elemental composition was analyzed via energy-dispersive X-ray spectroscopy (EDS). Results: indicated that dual treatment with HF and sandblasting showed descriptively higher SBS, with values ranging from 5.01 to 6.14 MPa, compared to 1.85 MPa in the sandblasting-only group. ESEM revealed that higher HF concentrations (10%) created more porous and irregular surfaces, while EDS indicated an increased fluorine presence trend and silicon reduction, indicating deeper chemical activation. However, extending HF exposure beyond 20 s did not further improve bonding, suggesting the importance of protocol optimization. Conclusions: The preliminary observations suggest a synergistic effect of mechanical and chemical conditioning on hybrid ceramic adhesion, but values should be interpreted qualitatively due to the pilot nature of the study. Manufacturer-recommended air abrasion alone may provide limited adhesion under high-stress conditions, although this requires confirmation in studies with larger sample sizes and ageing simulations. Future studies should address long-term durability and extend the comparison to other hybrid CAD/CAM materials and to other etching protocols. Full article

Agricultural biomass has potential as a renewable and versatile carbon feedstock for developing eco-friendly and biodegradable polymers capable of replacing conventional petrochemical plastics. To address the growing environmental concerns associated with plastic waste and carbon emissions, lignocellulosic residues, edible crop by-products, and algal biomass were utilized as sustainable raw materials. These biomasses provided carbohydrate-, lipid-, and lignin-rich fractions that were deconstructed through optimised physical, chemical, and enzymatic pretreatments to yield fermentable intermediates, such as reducing sugars, organic acids, and fatty acids. The intermediates were subsequently converted through tailored microbial fermentation processes into biopolymer precursors, primarily polyhydroxyalkanoates (PHAs) and lactate-based monomers. The resulting monomers underwent polymerization via polycondensation and ring-opening reactions to produce high-performance biodegradable plastics with tunable structural and mechanical properties. Additionally, the direct extraction and modification of naturally occurring polymers, such as starch, cellulose, and lignin, were explored to develop blended and functionalized bioplastic formulations. Comparative evaluation revealed that these biomass-derived polymers possess favourable physical strength, thermal stability, and biodegradability under composting conditions. Life-cycle evaluation further indicated a significant reduction in greenhouse gas emissions and improved carbon recycling compared to fossil-derived counterparts. The study demonstrates that integrating agricultural residues into bioplastic production not only enhances waste valorization and rural bioeconomy but also supports sustainable material innovation for packaging, farming, and consumer goods industries. These findings position agriculture-based biodegradable polymers as a critical component of circular bioeconomy strategies, contributing to reduced plastic pollution and improved environmental sustainability. Full article

Extracellular polymeric substances (EPS) play crucial roles in the growth and survival of microorganisms. However, the lack of effective evaluation for extraction methods has limited further investigations and applications of EPS. This study established a quantitative assessment system for algal EPS thermal extraction methods based on extraction yield, cell integrity, and EPS chemical properties. An extraction efficiency parameter (ε) was introduced to quantify the relationship between EPS yield and cell rupture. Thermal treatment proved to be an effective approach for algal EPS extraction. Using the proposed evaluation system, the extraction methods for EPS of Microcystis were compared and optimized, including the following treatments: NaOH, NaCl, and buffer solutions (borate, phosphate, Tris-HCl). The results demonstrated that heating at 55 °C for 30 min with borate buffer achieved the highest extraction efficiency for EPS, with an ε value of 11.06 ± 1.13. In contrast, NaOH treatment at 60 °C for 30 min resulted in 30.4% cell rupture and the lowest ε value (9.7 ± 0.81). Furthermore, the modeled cell rupture rates aligned with flow cytometry and three-dimensional fluorescence spectroscopy analyses. The EPS extraction evaluation system developed in this study was empirically validated as a robust tool for optimizing extraction protocols for algal EPS. Full article

Extracellular polymeric substances (EPSs) produced by actinomycetes of the genus Rhodococcus play crucial roles in their ecological success, metabolic versatility, and biotechnological value. This review summarizes existing studies of Rhodococcus EPSs, emphasizing the biochemical composition, functional attributes, and practical significance of EPSs, as well as their importance in biomedicine, bioremediation, and other applications (food industry, biomineralization) with respect to the EPS chemical composition and biological roles. Rhodococcus species synthesize complex EPSs composed primarily of polysaccharides, proteins and lipids that, like in other bacteria, support cell adhesion, aggregation, biofilm formation, and horizontal gene transfer (and can prevent exogenous DNA binding) and are highly important for resistance against toxicants and dissolution/assimilation of hydrophobic compounds. EPSs produced by different species of Rhodococcus exhibit diverse structures (soluble EPSs, loosely bound and tightly bound fractions, capsules, linear and branched chains, amorphous coils, rigid helices, mushroom-like structures, extracellular matrix, and a fibrillar structure with a sheet-like texture), leading to variations in their properties (rheological features, viscosity, flocculation, sorption abilities, compression, DNA binding, and interaction with hydrophobic substrates). Notably, the EPSs exhibit marked emulsifying and flocculating properties, contributing to their recognized role in bioremediation. Furthermore, EPSs possess antiviral, antibiofilm, anti-inflammatory, and anti-proliferating activities and high viscosity, which are valuable in terms of biomedical and food applications. Despite extensive industrial and environmental interest, the molecular regulation, biosynthetic pathways, and structural diversity of Rhodococcus EPSs remain insufficiently characterized. Advancing our understanding of these biopolymers could expand new applications in biomedicine, bioremediation, and biotechnology. Full article

This narrative review examines contemporary applications of polymeric materials in dentistry from 2020 to 2025, spanning prosthodontics, restorative dentistry, orthodontics, endodontics, implantology, diagnostics, and emerging technologies. We searched PubMed, Scopus, Web of Science, and Embase for peer reviewed English language articles and synthesized evidence on polymer classes, processing routes, mechanical and chemical behavior, and clinical performance. Approximately 116 articles were included. Polymers remain central to clinical practice: poly methyl methacrylate (PMMA) is still widely used for dentures, high performance systems such as polyether ether ketone (PEEK) are expanding framework and implant-related indications, and resin composites and adhesives continue to evolve through nanofillers and bioactive formulations aimed at improved durability and reduced secondary caries. Thermoplastic polyurethane and copolyester systems drive clear aligner therapy, while polymer-based obturation materials and fiber-reinforced posts support endodontic rehabilitation. Additive manufacturing and computer aided design computer aided manufacturing (CAD CAM) enable customized prostheses and surgical guides, and sustainability trends are accelerating interest in biodegradable or recyclable dental polymers. Across domains, evidence remains heterogeneous and clinical translation depends on balancing strength, esthetics, biocompatibility, aging behavior, and workflow constraints. Full article

Microplastics (MPs) and nanoplastics (NPs) are widespread environmental contaminants with documented impacts on human health, particularly on the female reproductive system. Defined as polymeric fragments smaller than 5 mm, MPs (typically ranging from 1 µm to 5 mm) and NPs (smaller than 1 µm, often <100 nm) originate either from primary sources—intentionally manufactured for specific industrial applications—or from secondary sources through physical, chemical, or biological degradation of macroplastics. Human exposure occurs via multiple routes, including ingestion, inhalation, dermal absorption, and iatrogenic introduction, with growing evidence that these particles can accumulate in the ovaries, oocytes, and placental tissue. Experimental studies in rodents demonstrate that MPs and NPs induce oxidative stress, trigger inflammatory responses, and promote granulosa cell apoptosis, ultimately diminishing ovarian reserve and impairing folliculogenesis. Clinical and pilot human studies have confirmed the presence of MPs in placentas, umbilical cord blood, and meconium, indicating exposure from the earliest stages of development. Moreover, MPs and NPs may disrupt the hypothalamic–pituitary–ovarian axis, contributing to endocrine dysregulation and hormonal imbalance. Analytical methods such as Fourier-transform infrared spectroscopy, Raman spectroscopy, and scanning electron microscopy enable detection of these particles in biological samples, although methodological standardization remains insufficient. This paper summarizes current evidence on the exposure pathways, toxicological effects, and reproductive consequences of MPs and NPs in women. It further highlights existing research gaps and evaluates available analytical approaches to support future studies and develop strategies aimed at mitigating their detrimental impact on women’s reproductive health and fertility. Full article

Tea’s chemical composition is influenced by cultivar, harvest maturity, and growing environment; however, processing remains the dominant factor shaping final quality. Despite the diversity of Taiwanese native teas, systematic comparisons of functional components across multiple manufacturing stages remain limited. In this study, nine representative Taiwanese teas were evaluated at four key processing stages—green tea (G), enzymatic fermentation (oxidative fermentation, F), semi-finished tea prior to roasting (S), and completed tea (C)—to clarify how enzymatic oxidation, rolling, and roasting alter major bioactive constituents. Green-tea-stage samples exhibited clear cultivar-dependent profiles: large-leaf cultivars contained higher catechins and gallic acid, whereas bud-rich small-leaf teas showed elevated caffeine and amino acids, with amino acids further enhanced at higher elevations. Fermentation intensity governed the major chemical transitions, including catechin depletion, gallic acid formation, accumulation of early stage catechin-derived paired oxidative polymerization compounds (POPCs), and pronounced increases in theasinensins in heavily fermented teas. L-theanine decreased most markedly in teas subjected to prolonged withering. Roasting further reduced amino acids but had minimal influence on caffeine, while rolling effects varied by tea type. Overall, this study provides the first stage-resolved chemical map of Taiwanese native teas, offering practical insights for optimizing processing strategies to enhance functional phytochemical profiles. Full article

The advancement of efficient and stable perovskite solar cells (PSCs) increasingly depends on developing flexible, metal-free electrode architectures. Single-walled carbon nanotubes (SWCNTs) offer chemical robustness, high conductivity, and mechanical flexibility, making them promising candidates to replace brittle metal cathodes. However, pristine SWCNTs are intrinsically p-type, creating energy barriers and recombination losses in inverted (p–i–n) PSCs. Achieving stable n-type doping compatible with both SWCNTs and perovskites is therefore critical. Here, seven representative n-type dopants, small molecules (TBD and TPP), ionic salts (TBAI, TBABr, and B18C6·KCl), and polymers (PEI and PVP) were systematically investigated to elucidate their effects on doping efficiency and interfacial stability. Morphological, structural, and electronic analyses supported by DFT calculations reveal that strong bases and ionic dopants promote perovskite degradation, whereas polymeric and coordination-type dopants preserve crystallinity and surface uniformity. Among them, PEI- and TPP-doped SWCNT electrodes achieved the best device performance, with power conversion efficiencies of 9.6% and 8.1%, respectively, demonstrating efficient electron extraction and interfacial stability. These findings highlight that interfacial chemical compatibility rather than intrinsic donor strength governs the effectiveness of n-type SWCNT doping, providing rational design principles for stable, metal-free perovskite photovoltaics. Full article

Dielectric barrier discharge (DBD) plasma provides a solvent-free and energy-efficient approach for the in situ polymerization of styrene on cotton textiles. Traditional methods for polystyrene (PS) coating often require elevated temperatures, chemical initiators, or organic solvents, conditions that are incompatible with porous, heat-sensitive substrates such as cotton. In this work, we demonstrate that DBD plasma can initiate and sustain styrene polymerization directly on cotton fibers under ambient conditions. FT-IR spectroscopy confirms the consumption of the vinyl C=C bond and the formation of atactic, amorphous polystyrene. Thermogravimetric analysis indicates that the cotton coated with DBD polymerized PS exhibits enhanced thermal stability compared to cotton coated with commercial PS. Additionally, UV aging tests confirm that the plasma-deposited coating maintains its hydrophobicity after exposure to light. Together, these findings highlight DBD plasma as a sustainable and effective approach for producing hydrophobic, thermally robust, and UV-stable textile coatings without the need for solvents, initiators, or harsh processing conditions. Full article

Growing concern about the environmental impact of traditional packaging has driven the development of biodegradable edible films made from natural and functional biopolymers. Various by-products generated during harvesting can be subjected to valorization. Potato, a tuber with high starch content, and carrot, rich in β-carotene, represent important sources of polymeric matrix and bioactive compounds, respectively. Similarly, the use of biodegradable plasticizers such as pectin and polysaccharides derived from nopal mucilage is a viable alternative. This study assessed the physical and chemical properties of edible films composed of potato starch (PS), cactus mucilage (NM), carrot extract (CJ), citrus pectin (P), and glycerin (G). The films were produced by means of casting, with three mixtures prepared that had different proportions of CJ, P, and PS. The experiments were adjusted to a simple mixture design, and the data were analyzed in triplicate, using Pareto and Tukey diagrams at 5% significance. Results showed that adding CJ (between 5 to 6%), P (between 42 to 44%) and PS (between 43 to 45%) significantly affects all of the evaluated physical and chemical properties, resulting in films with luminosity values greater than 88.65, opacity ranging from 0.20 to 0.54 abs/mm, β-carotene content up to 26.11 μg/100 g, acidity between 0.22 and 0.31% and high solubility with a significant difference between treatments (p-value < 0.05) and low water activity (around of 0.47) (p-value > 0.05). These characteristics provide tensile strength up to 5.7 MPa and a suitable permeability of 1.6 × 10⁻² g·mm/h·m²·Pa (p-value < 0.05), which ensures low diffusivity through the film. Similarly, increasing the CJ addition enables the functional groups of the other components to interact. Using carrot extract and potato starch is a promising approach for producing edible films with good functional qualities but with high permeability. Full article

In this study, dextran-based hydrogels were synthesized in dimethyl sulfoxide via free-radical polymerization with three structurally different crosslinking agents: divinyl benzene (DVB), diethylene glycol diacrylate (DEGDA), and 4,4′-di(methacryloylamino)azobenzene (DMAAazoB). Their morphology, swelling ability, mechanical properties, and potential for controlled release of the model substance (uracil) were examined, with the results showing that the chemical structure and chain length of the crosslinking agents significantly influence the structural and functional properties of hydrogels. Hydrogels crosslinked with DMAAazoB showed the highest swelling ability at pH 3 and pH 6 (2552 and 1696%, respectively), associated with protonation effects and sponge-like morphology, while simultaneously showing the lowest mechanical strength (20 and 47 MPa). In vitro simulations of gastrointestinal digestion showed that uracil was not released in the gastric phase, while in the intestinal environment, the release was significant, especially in Dex-DMAAzoB hydrogels (88.52%). The absence of azoreductases in the simulated system indicates that the release of the drug in real conditions would likely be even more pronounced. The Dex-DAAazoB hydrogel exhibited a slight antibacterial effect, producing inhibition zones of 8 and 7 mm against Escherichia coli ATCC 8739 and Staphylococcus epidermidis ATCC 12228, respectively. In contrast, the remaining hydrogel formulations showed no detectable antibacterial activity toward either bacterial strain, indicating their microbiological inertness and supporting their suitability as carrier matrices for antitumor drug delivery in colorectal cancer therapy. The obtained results confirm that azo-crosslinked dextran hydrogels, with an optimized amount of crosslinking agent, are promising carriers for the targeted and controlled delivery of antitumor drugs to the colorectal region. Full article

Naturally occurring bioactive compounds represent a promising option for cancer prevention and therapy due to their ability to modulate apoptosis, angiogenesis, inflammation, oxidative stress, and cell signaling. However, their clinical impact is limited by low bioavailability, chemical instability, rapid metabolism, and poor tumor microenvironment accumulation. Innovative delivery platforms, including lipid and polymeric nanoparticles, liposomes, micelles, nanoemulsions, hydrogels, and stimulus-responsive systems, have been developed to improve stability, absorption, tumor specificity, and therapeutic efficacy. This review integrates molecular mechanisms, preclinical and clinical evidence, and recent technological advances, highlighting both potential and limitations. Although several compounds show encouraging results in cell and animal models, only a small number have progressed to early clinical trials, where outcomes remain heterogeneous and often fail to replicate preclinical magnitudes. Regulatory barriers, a lack of formulation standardization, and the absence of predictive biomarkers persist. Sustainability is also addressed through the valorization of agrifood by-products and green extraction processes. This review provides an integrative framework linking molecular mechanisms, advanced delivery technologies, clinical translation, and sustainability, offering a broader perspective than conventional reviews. Future perspectives emphasize multicenter trials, comparative designs, and the development of regulatory guidelines for nanoformulated bioactive compounds. Full article

Electrospun polymeric nanofibers have emerged as promising materials for wound management owing to their high surface area, efficient exudate absorption and gas exchange, and extracellular-matrix-like architecture. This study investigates the fabrication of nanofiber dressings from poly(vinyl alcohol) (PVA) and hyaluronic acid (HA), prepared by fully aqueous electrospinning (without organic solvents) for potential wound-care applications. HA incorporation is expected to influence hydration and matrix interactions, properties that have been associated with modulation of wound healing in previous studies. However, the high solubility of PVA-based NFs in aqueous environments limits their use in biological applications. To address this issue, PVA/HA nanofibers were chemically crosslinked through a solid-state esterification process at 150 °C using biocompatible citric acid (CA). The electrospinning parameters were optimized to obtain PVA/HA fibers with diameters ranging from 130 to 200 nm, which were assembled to form mats with different porosity and intersection density. FTIR confirmed the formation of ester bonds, while DSC analysis showed an increase in Tg from 41 °C to about 55 °C and a slight decrease in Tm after crosslinking. Swelling and degradation analyses demonstrated a significant enhancement in hydrolytic stability, as the weight loss of the nanofiber mats decreased from ~90% in the non-crosslinked samples to less than 10% after 2 h of crosslinking. Dynamic mechanical analysis (DMA) showed an increase in Young’s modulus from ~70 MPa to 230 MPa after crosslinking. Overall, the results demonstrate the stabilizing effect of citric-acid crosslinking on PVA/HA nanofibers and support their potential use in wound dressings under physiological conditions. Full article