Scanning Electron Microscopy Analysis Research Articles

Optimisation of LPBF process parameters and residual stress analyses of Invar-10wt% TiC and Invar-10wt% TiN metal matrix composites

AbstractTo enhance the mechanical properties of Invar (Fe–36Ni) for a broader range of applications, reinforcement with Titanium Carbide (TiC) and Titanium Nitride (TiN) was investigated. Laser powder bed fusion was used to manufacture the Invar metal matrix composites with TiC and TiN respective additions. Optimization of the process parameters was conducted using response surface methodology. The optimal parameters for Invar-TiC are 180 W laser power with a scanning speed of 450 mm/s, while for Invar-TiN, the optimal parameters are 190 W laser power with a scanning speed of 400 mm/s. High densities (> 99%) and significant improvements in hardness were achieved. X-ray diffraction and scanning electron microscopy analyses confirmed the uptake of TiC and TiN into the Invar matrix, leading to the enhanced properties. Residual stress evaluation through non-destructive neutron diffraction (ND) measurements and inherent strain modelling (ISM) simulations was done. The addition of TiC and TiN to the Invar matrix influenced the stress distribution, with Invar-TiC showing higher tensile stresses due to its thermal conductivity properties, and higher compressive stresses due to grain refinement. Close agreement was found between the ISM simulation and ND-measured results, indicating predominantly compressive stresses in the interior and tensile stresses on the sample surfaces. These findings demonstrate the potential for developing Invar-based MMCs with enhanced mechanical properties through LPBF. Due to the enhancement in hardness and, thus, wear resistance, the investigated compositions offer applications in parts and tools used in rough and demanding conditions, such as mouthpieces for extrusion or turbine blades in water turbines.

Morphoanatomy and Histochemistry of Symplocos tetrandra (Mart.) Mart. (Symplocaceae).

The Symplocaceae family comprises 406 species, all of which are classified within a single genus, Symplocos Jacq., which is distributed across multiple continents. In Brazil, this genus is predominantly found in the Atlantic Forest and Cerrado regions and is characterized by the presence of secondary metabolites, such as iridoids, terpenoids, and saponins with biological activities. Moreover, the literature research has unveiled the potential of this genus for antimicrobial, antitumor, and anti-HIV applications. This research conducted morphoanatomical, histochemical studies using light microscopy and scanning electron microscopy (SEM) analysis of the leaves and stems of Symplocos tetrandra (Mart.) Mart. Cross-sections and paradermal were performed. The investigation revealed the presence of prismatic calcium oxalate crystal in petiole and druses calcium oxalate crystals, in petiole and leaf blade. Paracytic stomata on the abaxial surface, lignified pith in the stem, which was detected with the phloroglucinol staining. Oil bodies, uniseriate epidermis, and a thin lipidic cuticle were confirmed with Sudan III. These findings suggest potential anatomical markers for taxonomic classification of the species. The data obtained in this study contributes for species identification, and the presence of metabolites can guide future pharmacological investigation with S. tetrandra.

Islet-derived exosomal miR-204 accelerates insulin resistance in skeletal muscle by suppressing sirtuin 1: An in vivo study in a mouse model of high-fat diet-induced obesity.

The interaction between pancreatic islets and skeletal muscle plays a pivotal role in the development of insulin resistance. The present study aimed to elucidate the impact of non-hormonal molecules from islets on the insulin sensitivity of skeletal muscle cells. We developed a mouse model of obesity through a high-fat diet, assessing glucose tolerance and conducting miRNA sequencing on skeletal muscle samples. An in vitro model was established by treating cells with palmitic acid, and exosomes in the supernatant were characterized using scanning electron microscopy and CD63 expression analysis. Intracellular miR-204-5p levels were quantified by RT-PCR. Our in vivo model demonstrated a robust correlation between miR-204-5p level alterations and obesity-induced insulin resistance. Elevated fatty acid levels were observed to increase miR-204-5p in both skeletal muscle and islets. In cellular studies, palmitic acid increased miR-204-5p in MIN-6 islet β-cells but not in C2C12 skeletal muscle cells. Exosomes containing miR-204-5p, secreted by palmitic acid-treated MIN6 cells, were identified through morphological examination, immunoblotting for the exosomal marker CD63, and intraexosomal miR-204-5p level measurement. C2C12 cells were shown to uptake islet-derived miR-204-5p exosomes, as evidenced by the uptake of Exo-Red labeled exosomes. TargetScan analysis identified a highly conserved binding site for miR-204-5p in the 3' UTR of Sirt mRNA. Functional studies indicated that miR-204-5p overexpression reduced glucose consumption and uptake in C2C12 cells, decreased Sirt expression, and impaired insulin signaling, as evidenced by reduced Akt phosphorylation and membrane Glut4 levels. Our findings reveal that miR-204-5p contributes to the development of insulin resistance in obesity and acts as a signaling molecule in the crosstalk between pancreatic islets and skeletal muscle.

Biodegradation and Thermomechanical Behavior of 3D-Printed PLA Scaffolds Under Static and Stirring Biomimetic Conditions

3D-printed biomedical polylactic acid (PLA) scaffolds were developed, and their biodegradation, as well as their thermomechanical behavior, were studied in a relevant in vitro environment. The scaffold’s biodegradability profile has been monitored after immersion in a cell culture medium that contains components of blood and body fluids. Two types of biodegradation experiments were performed—a standard static one and an adapted stirring one, mimicking the body fluids’ flow, respectively—to achieve a comparative investigation. The biodegradation experiment’s duration was one month. The measurements were performed between days 1 and 28. The scaffold microstructure was analyzed with scanning electron microscopy (SEM). The weight loss of the scaffolds has been monitored. Differential scanning calorimetry (DSC) has been used to evaluate the glass transition temperature (Tg) of the scaffolds and to draw useful conclusions about their thermal behavior. Finally, dynamic mechanical analysis (DMA) was applied to investigate the viscoelastic behavior of the samples. The SEM analysis demonstrated that the samples in a static experiment are more damaged, while those in the stirring experiment are more brittle. The maximum Tg value of the material measured by DSC is around 65 °C. This value is reached after 5 days of immersion in static conditions and after 14 days of immersion after stirring, indicating that some processes take place faster in the static experiment. The variation of the Tg vs. immersion time, as derived from DSC vs. DMA measurements, gives similar results for both static and fluid absorption conditions, demonstrating the reproducibility of the results.

Effect of Teak Wood Dust as Filler Material on Mechanical Properties of Abaca-Pineapple-Epoxy Hybrid Composite

ABSTRACT Composite manufacturers and consumers are increasingly turning to natural-based composites for their biocompatibility, cost-effectiveness, and widespread availability. This study investigates the potential of using teak wood dust as an economical filler material, combined with natural fibers, within an epoxy matrix to create a composite. Specifically, it examines how varying concentrations of teak wood dust—3 wt%, 6 wt%, and 9 wt%—affect the mechanical properties such as tensile strength, flexural strength, impact resistance, inter-laminar shear strength (ILSS), and hardness of an abaca-pineapple-epoxy hybrid composite. The composites were fabricated using the hand layup method followed by hot pressing. Among the different configurations, the composite with 6 wt% teak wood dust (SD-6) demonstrated superior performance, with improvements in tensile, flexural, ILSS, and impact strengths ranging from 3% to 35% compared to other variants. Scanning Electron Microscope (SEM) analysis of the fractured surfaces indicated that the inclusion of 6 wt% teak wood dust enhanced fiber-matrix adhesion, leading to improved mechanical properties of the composite.

Surface characteristics of resin composite cores and bond strength to CAD/CAM resin matrix glass-ceramic restorations after different treatment protocols.

The purpose of this study was to evaluate the impact of various mechanical surface treatments on thesurface roughness and microtensile bond strength (µTBS) of aged composite resin cores bonded to CAD/CAM restorations. Composite resin specimens (Filtek Z350 XT, 3M-ESPE/Solventum) were thermally aged and subsequently divided into four groups (n = 36) according to surface treatments: UI-cleaning with ultrasonic diamond tip; AO-sandblasting with 50µm Al2O3; DB-cleaning with diamond burs; and CG-positive control group, without aging or surface treatment. Surface roughness was assessed using a profilometer and interferometer, with measurements taken on both sides of each specimen (n = 12). The surface characteristics were further analyzed through scanning electron microscopy (SEM) (n = 12). In addition, PMMA blocks were temporarily cemented (n = 12) onto the resin blocks, and after surface treatments, resin matrix glass-ceramic blocks were adhesively luted with dual-cure resin cement (RelyX Ultimate, 3&nbsp;M-ESPE/ Solventum, St. Paul, MN, USA) to the resin composite substrates. The CG specimens were adhesively luted to the indirect restorations without temporary restorations or surface treatment. After luting, the specimens were sectioned and tested for µTBS. The results (p = 0.05) from the profilometry and interferometry analyses indicated the highest surface roughness values for the DB group, followed by AO, UI, and CG. SEM analysis revealed marked morphological differences among the groups. Regarding µTBS, the GC specimens (25.78 ± 5.70MPa) and UI specimens (25.56 ± 11.36MPa) exhibited statisticallysimilar values, which were superior to those of the AO (12.25 ± 4.34MPa) and DB (13.16 ± 5.59MPa) groups (p < 0.001), which showed comparable results. In conclusion, the use of ultrasonic diamond tips resulted in the most favorable outcomes in terms of cleaning effectiveness, surface roughness, and bond strength among the surface treatments analyzed for resin composite cores.

Optimization of preparation parameters and testing verification of carbon nanotube suspensions used in concrete

Abstract Carbon nanotubes (CNTs) have received extensive attention due to their exceptional properties and wide range of applications. However, the agglomeration of CNTs in aqueous solutions and organic solvents significantly limits their large-scale application. In this study, the microscopic morphology and dispersion stability of the CNT suspensions were analyzed, and the most suitable surfactant in this study was selected. The preparation parameters of the CNT suspensions were optimized, and uniaxial compression tests were conducted on carbon nanotube concrete (CNTC) prepared using the optimized parameters. Scanning electron microscope analysis was used to investigate the improvement in the microstructure of the concrete by CNTs. Transmission electron microscope micrographs of the polyvinyl pyrrolidone (PVP)-CNT suspensions exhibited a uniformly distributed CNT cross-linked network. The absorbance reduction ratio of PVP-CNT suspensions after standing for 90 days was 13.75 and 22.41%, respectively. The absorbance reduction ratio of the suspensions first increased and then decreased with increasing dispersant ratio and ultrasonic dispersion time and increased with increasing ultrasonic power ratio. Compared with that of plain concrete, the uniaxial compressive strength of CNTC significantly improved, with a maximum increase of 18.15% when the content was 0.10%, and the failure mode exhibited typical shear failure characteristics. The optimized preparation parameters for the CNT suspensions were a PVP-to-multiwalled carbon nanotube mass ratio of 4:1, an ultrasonic dispersion time of 20 min, and an ultrasonic power of 60%. These optimized parameters are ideal choices for preparing CNT cement-based composite suspensions.

Structural and morphological behavior of Al-based hybrid composites reinforced by SiC and WS2 inorganic material

Abstract Aluminum-based composites exhibit significant potential in automotive engineering, especially in engine components, with potential to improve efficiency and lifespan. The potential and usability of developing high-performance aluminum-based hybrid composites with silicon carbide and tungsten disulfide for automotive applications were investigated in the present study. This study investigates a novel aluminum-based hybrid composite, incorporating 10 wt.% SiC and varying WS2 concentrations (0–12 wt.%). WS2 addition reduces friction, enhancing engine efficiency and lifespan. The structural and morphological features with mechanical behavior of the hybrid composites manufactured via powder metallurgy were examined. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis reveals the phase identification with topographical features. Microstructural analysis reveals uniform SiC distribution and WS2 clustering at aluminum grain boundaries. Microhardness increases from 52.86 ± 1.264 HV to 71.12 ± 2.175 HV with increase in WS2 (1–9 wt.%). Wear decreases from 70.56 to 8.48 μm, indicating better lubrication. After 120 h, corrosion rates drop from 0.041 to 0.013 mm a−1 with WS2 (up to 9 wt.%). The research findings suggest that with addition of WS2 and SiC improves corrosion resistance and hardness, minimizing wear.

Enhancing the mechanical properties of FDM 3D printed PETG parts with high pressure cold isostatic pressing

This study examined the effects of cold isostatic pressing (CIP) as a post-processing method for polyethylene terephthalate glycol-modified (PETG) parts produced by fused deposition modeling (FDM) 3D printing. To analyze the mechanical properties of CIP, 3D printed specimens were subjected to CIP at pressures ranging from 250 to 1000 bar with holding times of 1 to 10 min, followed by tensile, flexural, and interlaminar shear strength tests. Scanning electron microscope (SEM) and X-ray diffraction (XRD) analyses were performed for morphological and chemical property changes. The mechanical properties were generally optimal at 500–750 bar, indicating a significant improvement. SEM analysis revealed that the interlayer gaps and void areas decreased, with the porosity reduced by 4.46 times compared to the untreated samples. XRD analysis showed that the CIP treatment did not significantly alter the chemical structure of PETG and maintained its amorphous characteristics. These results suggest the potential of CIP as an effective post-processing technique that improves the mechanical properties while preserving the basic material characteristics of FDM-printed parts.

Synthetic conduits efficacy in neural repair: a comparative study of dip-coated polycaprolactone and electrospun polycaprolactone/ polyurethane conduits.

Peripheral nerve injuries represent the most common type of nervous system injuries, resulting in 5 million injuries per year. Current gold standard, autografts, still carry several limitations, including the inappropriate type, size, and function matches in grafted nerves, lack of autologous donor sites, neuroma formation, and secondary surgery incisions. Polymeric nerve conduits, also known as nerve guides, can help overcome the aforementioned issues that limit nerve recovery and regeneration by reducing tissue fibrosis, misdirection of regenerating axons, and the inability to maintain long- distance axonal growth. Polymer-based double-walled microspheres (DWMS) are designed to locally and in a sustainable fashion deliver bioactive agents. Lysozyme is a natural antimicrobial protein that shares similar physical and chemical properties to glial cell line-derived neurotrophic factor (GDNF), making it an ideal surrogate molecule to evaluate the release kinetics of encapsulated bioagent from polymeric biodegradable microspheres embedded in Polycaprolactone and Polycaprolactone/Polyurethane blend nerve conduits.&#xD;Approach: Lysozyme was encapsulated in poly(lactic-co-glycolic acid)/poly(L-lactide) (PLGA/PLLA) double-walled microspheres fabricated through a modified water-oil-water emulsion solvent evaporation method. Lysozyme-loaded DWMS were further embedded in PCL and PCL-PU based nerve guides constructed via polymer dip-coating and electrospinning method respectively. Lysozyme DWMS and nerve guides were imaged using scanning electron microscopy (SEM). Released lysozyme concentration was determined by using a colorimetric micro-BCA protein assay and spectrophotometric quantitation. Tensile and suture pull-out tests were utilized to evaluate the mechanical properties of both dip-coated and electrospun nerve guides, embedded and free of lysozyme DWMS.&#xD;Main Results: The study revealed significant distinctions in the lysozyme release profiles, and mechanical properties of the manufactured polymer nerve guides. Both PCL dip-coated and PCL/PU electrospun DWMS-embedded nerve guides revealed biphasic protein release profiles. PCL/PU electrospun and PCL dip-coated nerve guides released 16% and 29% of the total protein concentration within 72 hours, plateauing at week 16 and week 8, respectively. SEM analysis of the nerve guides confirmed the homogeneity and integrity of the polymer nerve guides' structures. The electrospun guides were found to be more flexible with a higher extension under stress bending, while the dip-coated PCL nerve guides displayed more rigid behavior.&#xD;Significance: This study provides useful insights on how to optimize nerve guide design and fabrication to enhance recovery progress of peripheral nerve injuries.&#xD.

Ultrasound Treatment Combined with Rhamnolipids for Eliminating the Biofilm of Bacillus cereus

Biofilm formation by Bacillus cereus is a major cause of secondary food contamination, leading to significant economic losses. While rhamnolipids (RLs) have shown effectiveness against Bacillus cereus, their ability to remove biofilms is limited when used alone. Ultrasound (US) is a non-thermal sterilization technique that has been found to enhance the delivery of antimicrobial agents, but it is not highly effective on its own. In this study, we explored the synergistic effects of combining RLs with US for biofilm removal. The minimum biofilm inhibitory concentration (MBIC) of RLs was determined to be 32.0 mg/L. Using a concentration of 256.0 mg/L, RLs alone achieved a biofilm removal rate of 63.18%. However, when 32.0 mg/L RLs were combined with 20 min of US treatment, the removal rate increased to 62.54%. The highest biofilm removal rate of 78.67% was observed with 256.0 mg/L RLs and 60 min of US exposure. Scanning electron microscopy analysis showed that this combined treatment significantly disrupted the biofilm structure, causing bacterial deformation and the removal of extracellular polymeric substances. This synergistic approach not only inhibited bacterial metabolic activity, aggregation, and adhesion but also reduced early biofilm formation and decreased levels of extracellular polysaccharides and proteins. Furthermore, US treatment improved biofilm permeability, allowing better penetration of RLs and interaction with bacterial DNA, ultimately inhibiting DNA synthesis and secretion. The combination of RLs and US demonstrated superior biofilm removal efficacy, reduced the necessary concentration of RLs, and offers a promising strategy for controlling biofilm formation in the food industry.

Comparative study of the stridulatory groove in species of Triatoma (Hemiptera: Reduviidae) from Mexico.

The stridulation in the subfamily Triatominae has been identified as a means of communication between species, produced by the friction of the proboscis on the prosternal stridulatory groove. Despite its biological significance, this phenomenon remains understudied, with the signal's production seemingly contingent upon the morphology of the stridulatory groove. In this study, we examined the morphology of stridulatory grooves in females and males of five species and two subspecies of Mexican triatomines using morphometric and scanning electron microscopical analysis. Our findings reveal that all analyzed species exhibit triangular-shaped stridulatory grooves with parallel ridges covering the entire groove, bordered on each side, and covered with setae. Surprisingly, we observed noticeable differences in the number of ridges and inter-ridge distance between the species Triatoma lecticularia and Triatoma rubida (p < 0.001 and p < 0.009, respectively), indicating sexual dimorphism in this aspect, a phenomenon not previously reported in the morphology of this structure. Our findings shed light on the intricate morphology of the stridulatory groove in Mexican triatomines, suggesting potential implications for their behavior and intra-specific communication.

Failure analysis of a large coal chemical reactor exhibiting bulging and cracking

Reactors represent the core components of coal chemical plants. Reactor failures can lead to significant operational hurdles, substantial financial losses, and potential casualties. Given these critical implications of reactor failures, thorough failure analyses of failed reactors are essential. This study investigated a failure incident involving bulging and cracking of a large coal chemical plant reactor. The failure analysis relied on several techniques, including macroscopic inspection, wall thickness measurement, mechanical property testing, hardness testing, metallographic analysis, and scanning electron microscopy analysis. The investigation confirmed that the failure of the reactor was caused by local overheating, which triggered high-temperature short-term creep, ultimately leading to bulging and cracking. To identify the factors responsible for this local overheating, a process analysis involving flow field and structural numerical simulations under abnormal working conditions was performed. The results of the flow field simulation, combined with field investigation data, revealed that the local overheating resulted from deposition or clogging of the distributor disk. Additionally, the extent of overheating was determined through the structural numerical simulation. In this paper, physical and chemical inspection, numerical modeling, and other means are comprehensively used to deduce the failure position through numerical simulation, to find out the failure reason, and to deduce the temperature range of failure. Overall, we hope that the results of this comprehensive failure analysis will provide valuable and experiential insights into the operation and maintenance of coal chemical plant reactors.

MICRO-MESO CHARACTERIZATION OF PREFABRICATED CONCRETE-CLT ADHESIVE JOINTS

This study evaluates the use of five commercially available epoxy adhesives (EAs), from low to high cost, as a connection alternative of timber-concrete composites (TCCs) using cross-laminated timber (CLT) and medium-strength precast concrete (25MPa). Five alternative EAs were initially evaluated via pull-off tests to determine the adhesive strength of the interface CLT/concrete, with average results varying from 0.6MPa to 3.6MPa. Subsequently, optical and scanning electron microscopy analyses were implemented to assess the microstructure of post-tested TCC specimens, finding that usually the CLT/concrete interface was not fully glued by the EAs and that there was a positive correlation between the penetration of each EA with the corresponding tension strength of the TCCs. Then, the three EAs with the largest adhesive strengths were further tested by small double-shear (SDS) tests evaluating their shear strength and deformation, as well as damage evolution and failure modes, which were obtained using digital image correlation. The SDS test average results ranged from 2.4MPa to 8.8MPa, and the EA with the best behavior was not the one with the highest tensile strength, but rather with the highest EA penetration into concrete, demonstrating that this property highly positively impacted the shear strength of TCCs. Finally, cost/benefit analyses were obtained, and interestingly, the EA with the best adhesive/shear performance was not the most expensive alternative, opening the discussion that, even though mostly expensive EAs have been used in TCCs, the option of technically valid and low-cost EA is feasible.

From waste to sustainable production: Experimental design and optimization of sustainable concrete using response surface methodology and life cycle assessment

This study focuses on a holistic approach to investigate the engineering properties (microstructural, mechanical, environmental, and economic) of sustainable concretes produced using recycled aggregate and supplementary cementitious material (SCM). Compressive strength tests was conducted on 24 sustainable concrete series for the mechanical properties. Statistical analyses were performed using the response surface methodology, and mathematical models were developed considering the strength values obtained. Developed model-based optimization solutions were applied to determine the mix proportions of the optimization series containing lower cement dosage and SCM with the same hardened concrete properties as the reference concrete series. Considering these mix proportions, life cycle assessments were performed and environmental and economic properties were compared. A comparison of Ref-6 and Opt-6 series reveals that the global warming potential (GWP), energy consumption (EC), and waste generation (WG) values are 422.4-330.9 kg CO2 eq, 1294-1044 MJ, and 1294-1222 kg, respectively. This situation resulted in a reduction of 21.7% in GWP values, 19.3% in EC values, and 5.6% in WG values. Similarly, the economic comparison of these series indicates that the total cost values are 81.9-75.7 €, respectively, resulting in 7.7% reduction. Finally, Scanning Electron Microscopy analyses were conducted to examine the microstructural properties. The use of fly ash at 10% improved the microstructure properties and increased the C-S-H gel formation. It is thought that the process of transition from these waste materials to sustainable production is of critical importance, especially in places that are heavily damaged after devastating earthquakes and where large amounts of waste materials are generated.

Impact of Alkali Concentration in Delignification Treatment for Cellulose Extraction from Rice Straw

Rice straw is an abundant agricultural byproduct with great potential as a sustainable source of cellulose. This study investigates the effect of sodium hydroxide concentration on the extraction of cellulose from rice straw through alkali delignification. Sodium hydroxide concentrations ranging from 3% to 11% were applied at a constant temperature of 60 °C for 60 minutes. The objective was to assess the impact of alkali concentration on cellulose yield and structural properties. Results showed that increasing alkali concentration led to a reduction in cellulose yield. Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM) confirmed the effective removal of lignin, hemicellulose, and impurities across all concentrations. Additionally, the crystallinity index (CI) increased from 47.85% to 51.37% as alkali concentration rose, indicating successful delignification. However, a balance must be considered, as lower alkali concentrations, while environmentally friendlier and yielding more cellulose, resulted in lower purity, with FTIR, SEM, and XRD analyses revealing residual impurities in the extracted cellulose. This eco-friendly process offers a promising method for converting agricultural waste into valuable cellulose, contributing to sustainable industrial practices.

A sustainable approach for the corrosion control of mild steel using Cocous nucifera gum: An electrochemical investigation

The study of corrosion inhibition on mild steel (MS) in an acid medium (1 M HCl) solution was performed using a crude extract of Cocousnucifera gum (CNG). Cocousnucifera develops gum exudates on its palm, the exudate process occurs mainly after some physical or microbiological injuries and is formed on the fruit of the palm. The gum was utilized to study the corrosion inhibition of MS by electrochemical and surface studies. The characterization of the crude gum was done by Fourier transform infrared spectroscopy (FT-IR) which revealed the presence of several active components (aromatic and oxygen-containing functional groups) in its structure. The electrochemical studies resulted in the maximum inhibition efficiency value of 75.64 % at the highest inhibitor concentration of 4000 ppm at 308 K. It was inferred that both the anodic dissolution of the metal and cathodic hydrogen evolution were effectively decreased in the presence of Cocous nucifera gum extract, revealing that inhibitor is of mixed type. From the adsorption studies, it was found that the best fit with R2 ∼ 0.9 followed Langmuir adsorption isotherm indicating the monolayer adsorption of the inhibitor on the metal surface. Gibb’s free energy of adsorption values was found <−20 kJ/mol, a characteristic of predominant physical adsorption. To support the electrochemical data SEM (scanning electron microscopy), AFM (Atomic force microscopy), and X-ray diffraction analysis were performed and these are in good agreement.

Enhanced chitosan fibres for skin regeneration: solution blow spinning and incorporation with platelet lysate and tannic acid

Abstract In this study, we developed and characterised enhanced chitosan/polyethylene oxide (PEO) nanofibre scaffolds using solution blow spinning (SBS) for potential application in skin tissue engineering. SBS enabled the efficient and scalable production of fibre matrices with precise morphology control, facilitating the integration of PEO to improve spinnability, 100X the speed of electron spinning. Following fabrication, fibres were subjected to potassium carbonate neutralisation to reduce PEO content, improving chitosan stability in aqueous environments. Characterisation by scanning electron microscopy (SEM) and attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR) confirmed structural integrity post-neutralisation and the successful incorporation with bioactive additives. Platelet lysate (PL) was incorporated to introduce growth factors, and tannic acid (TA) was added for antibacterial properties and enhanced mechanical stability through potential crosslinking. Mechanical testing showed that the optimised PL- and TA-enriched scaffolds exhibited the highest mechanical performance, with Young’s modulus of 7.0 ± 0.6 MPa, an ultimate tensile strength of 26.4 ± 2.3 MPa, elongation at break of 16.5 ± 1.7%, and toughness of 3.0 ± 0.3 MJ m−3 which is within the range of human skin. At the same time, SEM and ATR-FTIR analyses confirmed the stability and distribution of these functional agents within the fibre network. Biocompatibility tests with normal human dermal fibroblasts (NHDF) indicated low cytotoxicity, appropriate cell adhesion and proliferation over 14 days in culture, suggesting these scaffolds as promising candidates for wound healing and skin regeneration applications.

Environmental modification of cellulose fibers for reducing dye diffusion rate by anionic polyacrylamide

Reactive dyeing is the primary method for coloring cellulose fibers due to its vibrant colors, various hues, excellent colorfastness, and cost-effectiveness. However, this process consumes a large amount of water and chemicals, leading to significant environmental concerns due to the wastewater. Non-aqueous media/less water dyeing has emerged as a cleaner alternative, showing promising results in dyeing cotton fibers with reactive dyes. Nevertheless, the rapid adsorption rate of dyes can impact the evenness of dyeing. This study explores the use of anionic polyacrylamide (APAM) in the modification bath to reduce dye adsorption rate and enhance dye desorption during cellulose fibers dyeing. Fourier transform infrared spectroscopy (FT-IR) and field-emission scanning electron microscope (FSEM) analysis revealed effective interaction between APAM and cellulose fibers. Thermal gravimetric analysis (TGA), X-ray diffraction (XRD), and breaking strength tests indicated minimal impact on the thermal stability and physical properties of cellulose fibers with APAM modification. Zeta potential testing demonstrated that APAM modification reduced the surface potential of cellulose fibers and increased their negative charge. The adsorption rate of reactive dye decreased with APAM modification, while dye fixation, washing, and rubbing fastness remained largely unaffected. Adsorption isotherm results supported the weakening of the affinity between dyes and fibers after APAM treatment. Furthermore, the electrostatic potentials of fibers decreased after APAM modification. Compared to salt-free dyeing in non-aqueous media dyeing systems, anionic polymer modification not only improves the level dyeing performance of cotton fiber and reduces 0.9% in dyeing costs, but also increases production efficiency.

Implementation of Silver Nanoparticles Green Synthesized with Leaf Extract of Coccinia grandis as Antimicrobial Agents Against Head and Neck Infection MDR Pathogens.

Head and neck infections (HNI) associated with multidrug resistance (MDR) offer several health issues on a global scale due to inaccurate diagnosis. This study aimed to identify the bacteria and Candidal isolates and implement the silver nanoparticles green synthesized with leaf extract of Coccinia grandis (Cg-AgNPs) as a therapeutic approach against HNI pathogens. The Cg-AgNPs were characterized by the UV-visible spectrophotometer, FT-IR analysis, Zeta particle size, Zeta potential, and field emission scanning electron microscope (FESEM) analysis to validate the synthesis of nanoparticles. Additionally, the antimicrobial activity of Cg-AgNPs was presented by the zone of inhibition (ZOI), minimum inhibitory concentration (MIC), minimum bactericidal/fungicidal concentration (MBC/MFC), and antibiofilm assay. Moreover, the cell wall rupture assay was visualized on SEM for the morphological study of antimicrobial activities, and the in-vivo toxicity was performed in a swiss mice model to evaluate the impact of Cg-AgNPs on various biological parameters. Different bacterial strains (Staphylococcus aureus, Acinetobacter baumannii, Klebsiella pneumoniae, and Pseudomonas aeruginosa) and Candida sp. (Candida albicans, Candida tropicalis, Candida orthopsilosis, and Candida glabrata) were identified. The MIC, MBC, and antibiofilm potential of Cg-AgNPs were found to be highest against A. baumannii: 1.25 μg/ml, 5 μg/ml, and 85.01±5.19% respectively. However, C. albicans and C. orthopsilosis revealed 23 mm and 21 mm of ZOI. Subsequently, the micromorphology of the cell wall rupture assay confirmed the efficacy of Cg-AgNPs, and no significant alterations were seen in biochemical and hematological parameters on the swiss mice model in both acute and subacute toxicity studies. The green synthesized Cg-AgNPs have multifunctional activities like antibacterial, anticandidal, and antibiofilm activity with no toxicity and can be introduced against the HNI pathogens.