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Fused Filament Fabrication (FFF) is an additive manufacturing process with wide use. However, the optimization of certain parameters presents some uncertainties in the FFF process. In the present study, the effect of infill density (ID) on the flexural behavior of Polylactic Acid (PLA) parts printed by the FFF process was investigated. The experimental tests were performed on rectangular parts, according to the ISO 178 standard, with a test speed of 5 mm/min. Parts with several IDs in the 20–100% range were 3D printed, analyzed, and tested. Every sample was subjected to dimensional and mass analyses before the experimental tests. After testing, the failure mechanisms were highlighted depending on the ID. It was found that the ID of the printed parts strongly influences the flexural characteristics (elastic, strength, strain, and energy absorption). However, using the specific properties (specific modulus and specific strength), it was noted that 20%-ID is the optimal density for such AM structures. Slight dependencies on IDs were recorded for dimensional accuracy. It was obtained that at low IDs (⁢ [ 40%), the FFF-printed parts show a quasi-brittle fracture, and with its increase (IDs > 60%), a slight plastic deformation was observed.

Flexible and acrylic resins are used as denture bases. Acrylic resins derived from polymethyl methacrylate are the conventional approach. Flexible thermoplastic resins are the alternative, and of these, polyamides with low flexibility and ethylene propylene resins are often used in current practice. The biocompatibility, flexibility, non-allergenic properties, and ease of denture insertion all highlight the suitability of these materials. This study aims to evaluate the behavior of low flexibility polyamide, ethylene propylene resin, and polymethyl methacrylate resin, used as partial denture bases, by monitoring the specific parameters obtained. The evaluation of the behavior of the materials was carried out by clinical examination. Additionally, a questionnaire was used. The results with both flexible resins are almost similar and superior to conventional resins, in partially edentulous patients, in difficult clinical situations, on undercut prosthetic areas, and in extended edentulous, tilted teeth, or when the patient has a limited mouth opening. The prognosis over time with polyamides with low flexibility and ethylene propylene resins is more advantageous than with classic acrylic resins.

[b]Background:[/b] Barrier membranes prevent soft tissue invasion while promoting bone healing, suggesting a potential significance in guided bone regeneration (GBR). However, many resorbable membranes lack adequate mechanical strength and long-term stability. Polyethylene terephthalate (PET), a biostable polymer, exhibits promising properties for GBR but remains underexplored. [b]Methods:[/b] Electrospun PET nanofiber membranes (PET-1 to PET-4) were fabricated by systematically varying solution concentrations and processing conditions. Their morphology was analyzed by scanning electron microscopy (SEM), and mechanical properties were assessed via tensile testing. Surface wettability was reflected by the water contact angle. In vitro biocompatibility was evaluated using the CCK- 8 assay using L929 mouse fibroblasts. Barrier function was tested by Transwell and time-course fibroblast migration assays. [b]Results:[/b] All PET membranes exhibited uniform nanofiber structures with good mechanical integrity. PET-4 showed the highest tensile strength (13.5 MPa) and elastic modulus (190 MPa). Contact angles ranged from 85◦ to 93◦, which indicated moderate hydrophobicity. Cytocompatibility was high across all the groups, with PET-4 representing nearly 100% cell viability. In migration assays, PET-4 significantly suppressed fibroblast invasion over 48 h. [b]Conclusion:[/b] Electrospun PET nanofiber membranes demonstrated excellent mechanical performance, cytocompatibility, and barrier function. PET-4 emerged as a particularly promising candidate for GBR application, offering effective long-term soft tissue exclusion and bone regeneration support.

Lithography is a core-pattern transfer technique in micro/nanofabrication, among which electron-beam lithography (EBL) is a representative example. Polymethyl methacrylate (PMMA) has been widely employed as an electron-beam resist due to its high sensitivity, high resolution, and excellent contrast. However, commercial PMMA resists are relatively expensive and have complex formulations, thereby limiting process flexibility and cost control. Here, we demonstrate a rapid, low-cost preparation method for a PMMA resist suitable for micrometer-scale EBL. PMMA powder was dissolved in anisole to obtain a 4 wt% solution, which was spin-coated onto substrates to form uniform and smooth thin films. To evaluate resist performance, a custom-designed 5 × 5 array pattern was used to systematically study the effect of exposure dose on pattern quality. Results show that doses below 200 μC/cm² fail to induce complete scission of the PMMA molecular chains. Thermal evaporation and a lift-off process were employed to verify the dimensional accuracy of fabricated electrodes. Within the exposure dose range of 240–270 μC/cm², the electrode patterns were complete and exhibited straight edges. The optimal pattern fidelity was achieved at 260 μC/cm², with an absolute dimensional error below 0.2 μm, meeting the precision requirements of most micro/nanofabrication applications. This work provides a practical process reference for the preparation of PMMA electron-beam resists and their application in nanodevice fabrication.

[b]Background:[/b] Effective pain control is often limited by the short duration and systemic side effects of conventional lidocaine administration. Transdermal delivery systems offer a non-invasive alternative, but require materials that match skin mechanics and provide sustained drug release. [b]Methods:[/b] We designed a stretchable, biodegradable elastomer patch composed of a Poly(glycerol sebacate) (PGS) top layer and a lidocaine-loaded Poly(lactic-co-glycolic acid) (PLGA) reservoir. The patch’s mechanical properties, degradation behavior, drug release kinetics, transdermal permeation, and analgesic efficacy were systematically evaluated in vitro and in vivo. [b]Results:[/b] The patch exhibited a skin-like modulus and remained flexible during deformation. In vitro, it sustained lidocaine release over 48 h and degraded to ~20% mass over 30 days. Franz cell experiments confirmed effective skin permeation. In a rodent model, the patch significantly increased paw withdrawal thresholds compared to free drug. [b]Conclusion:[/b] This multilayer elastomer patch provides conformal adhesion, sustained lidocaine release, and enhanced local analgesia, offering a promising platform for non-invasive, long-acting pain management.

[b]Objective:[/b] To investigate and optimize the alkaline extraction process of Ganoderma lucidum polysaccharides, and to preliminarily explore their immunological activity. [b]Methods:[/b] Ganoderma lucidum was used as the raw material for the extraction of polysaccharides. A single-factor experiment was conducted to examine the effects of NaOH concentration, temperature, and extraction time on the total sugar content of the polysaccharides. Based on these results, response surface methodology was applied to optimize the extraction process. The total polysaccharide content, uronic acid content, monosaccharide composition, molecular weight, and cell viability were measured. [b]Results:[/b] The optimal extraction conditions were found to be a temperature of 93◦C, NaOH concentration of 0.40 mol/L, and extraction time of 172 min, yielding a total polysaccharide content of 47.66%. The monosaccharide composition of the extracted polysaccharides included mannose, glucuronic acid, glucose, galactose, arabinose, and fucose. Molecular weight analysis revealed two average molecular weights, 3.15 × 104 Da and 1.014 × 104 Da, indicating the polysaccharides were relatively small. Infrared spectroscopy showed the presence of β-type glycosidic linkages in the polysaccharides. In the cell viability assay, GLCP-1 enhanced the viability of RAW264.7 cells and significantly inhibited the viability of HepG2 cells. However, the specific regulatory mechanism remains unclear. [b]Conclusion:[/b] The study successfully optimized the alkaline extraction of Ganoderma lucidum polysaccharides and demonstrated their potential immunological activity, providing a foundation for the future exploration of their bioactivity and industrial production.

Clopidogrel is widely used for stroke prevention, but its oral administration is limited by poor patient adherence, gastrointestinal irritation, and hepatic first-pass metabolism. To address these limitations, we developed a biodegradable microneedle patch composed of poly(lactic-co-glycolic acid) (PLGA) and polyvinylpyrrolidone (PVP) for the transdermal delivery of clopidogrel. The patch exhibited sufficient mechanical strength to penetrate the skin simulant and fully dissolve within 6 h. Drug release was sustained over 48 h in vitro, and platelet aggregation was evaluated using a simulated human platelet-rich plasma (PRP) model. Compared to clopidogrel solution, the microneedle patch maintained longer antiplatelet activity, with significant inhibition observed up to 72 h. These findings suggest that dissolvable microneedle patches may serve as a non-invasive and sustained delivery strategy for clopidogrel, potentially improving therapeutic consistency and patient compliance in stroke prophylaxis.

Polypropylene (PP) is a commonly used raw material for the production of 3D printing composite filament, which has many advantages, such as low density, insulation, chemical resistance, and environmental friendliness, but its mechanical strength is poor, which affects the comprehensive performance of the 3D printing PP model. In order to effectively improve the flexural strength of material-extrusion-based 3D printing (ME-3DP) PP model, this study investigated the influence of three printing parameters (infill rate, extrusion speed, platform temperature) on the flexural strength of the 3D printed PP model through the three-point support flexural test. The results show that the flexural strength of 3D printed PP model gradually increases with the increase of the infill rate, the decrease of the extrusion speed, and the increase of the platform temperature; the degree of influence of the three parameters on the flexural strength of the 3D printed PP model is as follows: infill rate ] extrusion speed ] platform temperature; the optimal combination of the printing parameters is as follows: infill rate (90%), extrusion speed (20 mm/s), and platform temperature (70°C). The flexural strength of the 3D printed PP model fabricated according to the optimal printing parameters is 41.7 MPa, which is the maximum value in the orthogonal experiment, verifying the reliability of the experiment results.

This research describes the development of a new sustainable and high-performance hybrid polymer matrix composite (HPMC) that reduces ecological impact by adding waste-based piassava fiver as a key reinforcing, sustainable, and biodegradable material. The composite contains Kevlar and waste based-piassava fibers in an epoxy matrix with nanosilicon dioxide particles (SiO2 NPs) to have the desired mechanical properties for uses in aerospace, railway cabins, structural frameworks, sports, medical equipment, and so on. Employing the hand lay-up method and compression moulding, sixlayered composites were made with different stacking sequences (A to O type) and SiO2 nanoparticle content (0, 0.5, 1, 1.5, and 2 wt.%). N-type stacking (KKPPKK) at 1.5 wt.% SiO2 NPs achieved the highest level of performance. The optimized composition produced impressive tensile strength (336 MPa), and flexural strength (381 MPa). Further, M-type composites with 1 wt.% SiO2 NPs had the highest impact strength of 263 J/m. Among all the combinations, the N-type composites absorbed less water, with 8.96% absorption, making them more useful in wet conditions. By incorporating waste-based piassava fiber and optimal nano SiO2 filler, this research creates a new way to achieve lightweight, durable, and environmentally responsible composite hybrid materials, positioning with the aims of sustainable engineering and waste valorization.

Natural rubber is a material, of vital importance, which is formed not only by the Hevea brasiliensis tree but also by various plant species (Carica papaya, Ficus carica, Taraxacum kok-saghyz, Parthenium argentatum). Amongst these, only the species Taraxacum kok-saghyz and Parthenium argentatum are explored as alternative sources of natural products. The goal of this article was to assess the screening of latex extracts, the determination of density, the determination of total solids, the determination of alkalinity, the determination of conductivity, the determination of total polyphenol content, the determination of total flavonoid content, the determination of antioxidant activity, the rubber extraction and the determination of rubber moisture. The screening result revealed the presence of proteins, amino acids, fatty acids, carboxylic acids, resins, alkaloids, phytosterols, terpenes, diterpenes, terpenoids, coumarins, polyphenols, flavonoids, saponins, steroids and the absence of catechins, glycosides, xanthoproteins, and anthocyanins. Following the determinations, the following values of the determined parameters were obtained: density 0.977 g mL−1, total solids 43.5%, alkalinity 0.53%, conductivity 210 μS cm−1, total polyphenols 349.7 μg GAE mL−1, total flavonoids 13.4 mg EC g−1, DPPH antioxidant activity 59.75%, ABTS antioxidant activity 511 μg TEmL−1, rubber mass 3.78% and rubber moisture 98.2%.