Search Results (708)

The plasma-catalytic conversion of CO₂ is a promising route toward sustainable fuel and chemical production under mild operating conditions. However, many aspects still need to be better understood to improve performance and better understand the catalyst-plasma synergies. Among them, one aspect concerns understanding whether photons emitted by plasma discharges could induce changes in the catalyst, thereby promoting interaction between plasma species and the catalyst. This question was addressed by investigating the CO₂ splitting reaction in a planar dielectric barrier discharge (pDBD) reactor using titania-based catalysts that simultaneously act as discharge electrodes. Four systems were examined feeding pure CO₂ at different flow rates and applied voltage: bare titanium gauze, anodically formed TiO₂ nanotubes (TiNT), TiNT decorated with Ag–Au nanoparticles (TiNTAgAu), and TiNT supporting Ag–Au nanoparticles coated with polyaniline (TiNTAgAu/PANI). The TiNTAgAu exhibited the highest CO₂ conversion (35% at 10 mL min⁻¹ and 5.45 kV) and the most intense optical emission, even in the absence of external light irradiation, suggesting that the improvement is primarily attributed to plasma–nanoparticle interactions and self-induced localized surface plasmon resonance (si-LSPR) rather than conventional photocatalytic pathways. SEM analyses indicated severe plasma-induced degradation of TiNT and TiNTAgAu surfaces, leading to performance decay over time. In contrast, the TiNTAgAu/PANI catalyst retained structural integrity, with the polymeric coating mitigating plasma etching while maintaining competitive efficiency. There is thus a complex behavior with catalytic performance governed by nanostructure stability, plasmonic enhancement, and the interfacial protection. The results demonstrate how integrating plasmonic nanoparticles and conductive polymers can enable the rational design of durable and efficient plasma-photocatalysts for CO₂ valorization and other plasma-assisted catalytic processes. Full article

Metal ions exemplify one of the most harmful and environmentally detrimental contaminants of water systems. This work describes the creation of an innovative chelated carbon-doped nickel and titanium oxide (C-NiTiO₂) hybrid as an adsorbent for the effective elimination of metal ions. The dominance of the TiO₂ anatase phase with a ≈ 61 nm crystallite size was verified by XRD and Raman investigation. Morphology investigations exposed polygonal nanoparticles consisting of Ti, C, Ni, and O. The nanostructure exhibited a surface area of 17 m²·g⁻¹, a pore diameter of ≈1.5 nm, and a pore volume of 0.0315 cm³·g⁻¹. The nanostructure was evaluated for the elimination of Zn (II) ions from an aqueous solution. The metal ion adsorption onto the hybrid nanomaterial was described and comprehended using adsorption kinetics and equilibrium models. The adsorption data matched well with the pseudo-second-order kinetics and Langmuir adsorption models, indicating a monolayer chemisorption mechanism and achieving a maximum Zn (II) ion elimination of 369 mg·g⁻¹. Mechanistic investigation indicated film diffusion-controlled adsorption through inner-sphere complexation. The nanosorbent could be regenerated and reused for four rounds without appreciable activity loss, thus demonstrating its potential for water cleanup applications. Full article

The micromechanisms “slip transfer, slip irreversibility, microplasticity, and fatigue cracking” in titanium alloys are reviewed, with a special emphasis on near-α and α + β alloys. As the interplay between slip activity, microplasticity, and fatigue cracking governs both the microscale and macroscale mechanical response, we reveal how the slip irreversibility and localized dislocation activity at the grain boundaries (GBs) and α/β interfaces generate dislocation pile-ups and strain localization, subsequently driving fatigue crack initiation and propagation. The review highlights the favorable crack initiation along basal planes and the roles of α grain orientations, slip transfer barriers, and the β phase in governing fatigue cracking, while addressing unresolved questions about localized interactions and texture effects. It also explores the complex interactions that govern the effects of microstructures, textures, and defects on fatigue cracking. Ultimately, the review provides a unified framework for linking slip events to microplasticity and to fatigue failure, offering actionable insights for alloy design and fatigue prediction. Full article

Background: To compare the biomechanical strength of three fixation techniques for the elbow anterior capsule and coronoid process using a synthetic ulna model. We hypothesize that a cortical suture button would be equivalent to the bone tunnel model but inferior to a screw-post construct. Methods: A biomechanical study was conducted using a composite ulna bone model to simulate coronoid process fixation with three techniques: traditional trans-osseous bone tunnel repair, suspensory fixation using a cortical button, and a screw-post construct using a 3.5 mm cortical screw. All constructs were assembled using high-strength suture. Each specimen underwent axial loading on an Instron machine until failure, defined as loss of fixation through the dorsal cortex. Peak ultimate strength was recorded. Statistical analysis was performed using one-way ANOVA and Tukey’s HSD test. Results: The suture button construct demonstrated the highest mean ultimate strength at 490.3 ± 125.2 N, significantly greater than both the bone tunnel (328.8 ± 86.4 N, p < 0.01) and screw-post constructs (273.4 ± 54.5 N, p < 0.001). While the bone tunnel construct exhibited a 20.3% higher strength than the screw-post construct, this difference was not statistically significant (p = 0.13). The screw-post construct showed the least variability in strength to failure but the lowest overall strength. The suture button demonstrated the greatest mechanical strength but also the most variability. Conclusions: Suspensory fixation using a titanium cortical suture button provides significantly greater mechanical strength compared to traditional bone tunnel and screw-post techniques in a synthetic ulna model. While variability was greatest with the suture button construct, its superior load-bearing capacity suggests potential advantages in stabilizing the elbow through anterior capsule and coronoid fracture repair. These findings support further clinical investigation of suture button fixation as a viable technique in complex elbow injuries. Full article

Background/Objectives: Peri-implantitis is a chronic inflammatory condition affecting tissues surrounding dental implants and is characterized by progressive marginal bone loss that can ultimately lead to implant failure. Reduced vascularization and impaired immune clearance in peri-implant tissues contribute to persistent inflammation and limited therapeutic efficacy. MicroRNAs (miRNAs), particularly miR-21, have emerged as key regulators of inflammatory responses and bone remodeling. The objective of this study was to develop a bioactive dental implant coating capable of locally delivering miR-21 to modulate inflammation and promote peri-implant tissue regeneration, thereby preventing peri-implantitis. Methods: Cationic nanoparticles were synthesized using lecithin and low-molecular-weight polyethylenimine (PEI) as a non-viral delivery system for miR-21. Lecithin was employed to enhance biocompatibility, while PEI functionalization provided a positive surface charge to improve miRNA complexation and cellular uptake. The resulting lecithin–PEI nanoparticles (LEC–PEI NPs) were incorporated into a chitosan-based coating and applied to titanium implant surfaces to obtain a sustained miR-21–releasing system (miR21-implant). Transfection efficiency and biological activity were evaluated in human periodontal ligament fibroblasts (hPDLFs) and compared with a commercial transfection reagent (Lipofectamine). Release kinetics and long-term activity of miR-21 from the coating were also assessed. Results: MiR-21-loaded LEC–PEI nanoparticles demonstrated significantly higher transfection efficiency than Lipofectamine and retained marked biological activity in hPDLFs relevant to peri-implantitis prevention. The chitosan-based nanoparticle coating enabled controlled and sustained miR-21 release over time, supporting prolonged modulation of inflammatory and osteogenic signaling pathways involved in peri-implant tissue homeostasis. Conclusions: The miR21-implant system, based on lecithin–PEI nanoparticles incorporated into a chitosan coating, represents a promising therapeutic strategy for peri-implantitis prevention. By enabling sustained local delivery of miR-21, this approach has the potential to preserve peri-implant bone architecture, modulate chronic inflammation, and enhance the osseointegration of titanium dental implants. Full article

Maxillofacial skeletal reconstruction presents significant challenges due to anatomical complexity, functional requirements, and aesthetic demands. Traditional materials such as titanium and autogenous bone grafts have limitations, prompting interest in Polyetheretherketone (PEEK), a versatile thermoplastic polymer with advantages like biocompatibility, radiolucency, and elasticity similar to human bone. This multi-year case series evaluates the clinical outcomes of PEEK implants used in 56 cases on 53 patients for maxillofacial reconstruction, primarily for trauma (44 patients) and deformity (9 patients). PEEK implants were applied to various facial regions including the orbit, zygoma, mandible, and maxilla. The majority of surgeries utilised virtual surgical planning. Patient-specific implants were fabricated using 3D imaging technologies, allowing customisation for optimal fit and functionality. The mean patient age was 37 years with a split of 37 to 16 females. Some complications were noted such as infection and paraesthesia. However, the majority of patients experienced positive outcomes. The findings support PEEK implants as a safe, effective, and adaptable material for maxillofacial surgery, with potential for further advancements in material properties and surgical technologies to improve long-term outcomes. Full article

Additive manufacturing (AM) has emerged as a key enabling technology in contemporary dental manufacturing, driven by its capacity for customization, geometric complexity, and seamless integration with digital design workflows. This article presents a technology-oriented narrative review of additive manufacturing in dental implant production, focusing on dominant processing routes, material systems, and emerging research trends rather than a systematic or critical appraisal of the literature. An indicative descriptive analysis of publications indexed in the Web of Science and Scopus databases between 2014 and 2024 was used to contextualize the technological development of the field and identify major research directions. Emphasis was placed on metal powder bed fusion technologies, specifically Selective Laser Melting (SLM) and Direct Metal Laser Sintering (DMLS), which enable the fabrication of titanium implants with controlled porosity and enhanced osseointegration. Ceramic AM approaches, including SLA, DLP, and PBF, are discussed in relation to their potential for aesthetic dental restorations and customized prosthetic components. The publication trend overview indicates a growing interest in ceramic AM after 2020, an increasing focus on hybrid and functionally graded materials, and persistent challenges related to standardization and the availability of long-term clinical evidence. Key technological limitations—including manufacturing accuracy, material stability, validated metrology, and process reproducibility—are highlighted alongside emerging directions such as artificial intelligence-assisted workflows, nanostructured surface modifications, and concepts enabling accelerated or immediate clinical use of additively manufactured dental restorations. Full article

Investment casting of aluminum alloys is widely used in the aeronautical and automotive sectors for manufacturing complex components. However, conventional alloys lack sufficient mechanical strength and high-temperature resistance, prompting the need for enhanced materials. This study investigated the addition of submicron TiC particles, introduced via stir casting process, to an AlSi7Mg0.3 alloy for investment casting. Chemical analysis confirmed the incorporation of up to 0.1 wt.% TiC, but no significant improvement in tensile properties was observed. High Resolution Scanning Electron Microscopy (HRSEM) and Transmission Electron Microscopy (TEM) revealed a complex microstructure with few TiC particles and needle-shaped intermetallic phases containing titanium, iron, silicon, or aluminum. The high mold temperature (700 °C) and slow solidification rate likely caused partial TiC dissolution and intermetallic precipitation, which may have offset strengthening mechanisms like the Hall–Petch effect. Notably, the partial dissolution of TiC particles in investment casting has not been previously reported in similar alloys. These findings highlight the challenges of using particle-reinforced alloys in this process and emphasize the need for further research into process–microstructure relationships. Full article

Additive manufacturing (AM) of titanium alloys enables the production of complex, high-performance components, but the steep thermal gradients and rapid solidification involved make it challenging to control crystallographic texture and phase evolution. This review synthesizes the current understanding of how these thermal conditions influence grain morphology, texture intensity, and solid-state transformations in key alloys such as Ti-6Al-4V (Ti64), Ti-6Al-2Sn-4Zr-2Mo (Ti6242), Ti-5Al-5Mo-5V-3Cr (Ti5553), and metastable β-Ti systems processed by powder bed fusion-based processes (PBF) such as laser powder bed fusion (LPBF) and electron beam powder bed fusion (EBPBF/EBM). Emphasis is placed on mechanisms governing epitaxial columnar β-grain growth, α′ martensite formation, and the development of heterogeneous α/β distributions. The impact of processing variables on texture development and transformation kinetics is critically examined, alongside phase fractions. Across studies, AM-induced textures are consistently linked to mechanical anisotropy, with performance strongly dependent on build direction and alloy chemistry. Post-processing strategies, including tailored heat treatments and hot isostatic pressing (HIP), show clear potential to modify grain structure, reduce texture intensity, and stabilize desirable phase balances in titanium alloys. These insights highlight the emerging ability to deliberately engineer microstructures for reliable, application-specific properties in powder-based AM titanium alloys. Full article

In physiological environments, several metallic alloys, including titanium, stainless steel, cobalt–chromium, and emerging biodegradable systems such as magnesium (Mg), zinc (Zn), and iron (Fe), offer mechanical properties and biocompatibility suitable for load-bearing implants. With the rapid advancement of 3D printing technologies, these alloys can now be fabricated into patient-specific, complex geometries that enhance both structural performance and functional integration. Beyond serving as structural supports, 3D-printed alloys are increasingly engineered as localized drug-delivery platforms to release anti-inflammatory, antibacterial, anticancer, and osteogenic agents at the implant–tissue interface, addressing the dual clinical needs of site-specific therapy and mechanical stabilization. Nevertheless, this field remains underexplored because studies differ widely in alloy chemistry, surface topography, porosity, coating strategy, drug-loading methods, and release profiles, as well as in how material degradation or passivation interacts with pharmacokinetics. For the first time, this review consolidates drug-loading and elution strategies across 3D-printed alloy platforms, compares therapeutic categories in relation to alloy and coating types, and critically evaluates how the surface microstructure or alloy geometry influences release behavior. Full article

Alkaline water electrolysis is a widely researched method for hydrogen generation due to its low cost, scalability and its advantage of being able to produce hydrogen using only renewable energy. Enhancing the efficiency of electrolysis systems relies mainly on the development of high-performance ion-conductive membranes. The incorporation of ceramic fillers into polyvinyl alcohol (PVA) membranes as a composite material has shown considerable promise in enhancing the performance of electrolyzers. In this work, novel composite separator membranes for use in alkaline electrolyzers were developed from aqueous PVA solutions and physically crosslinked through a freeze–thawing process. To enhance the membrane properties, two types of ceramic fillers—titanium dioxide (TiO₂) and zirconium dioxide (ZrO₂)—were incorporated into the starting crosslinking solution. The thermal stability of these membranes was studied by a Differential Scanning Calorimetry (DSC) technique where we can conclude that addition of TiO₂ and ZrO₂ significantly influences the thermal properties of PVA membranes. These metal oxides enhance thermal stability, as shown by the shift in exothermic peaks toward higher temperatures and alterations in the degradation mechanism, evidenced by changes in the intensity and number of DSC peaks. The effect is concentration-dependent for TiO₂, where higher contents produce more pronounced yet increasingly complex thermal behavior. Compared with commercial membrane (Zirfon Perl), these types of membranes exhibit better electrochemical performance at ambient temperature and pressure; however, the process of preparation is simpler, reducing the cost of the hydrogen production process. The polarization curves (U-I curves) indicated a decrease in voltage with the addition of an ionic activator based on cobalt and molybdenum. Conductivity measurements performed using electrochemical impedance spectroscopy utilizing a two-probe method revealed that PVA membranes with TiO₂ exhibit ionic conductivity comparable to that of the commercial membrane. Compared to the commercial membrane, these types of membranes demonstrated similar mechanical properties and improved electrochemical performance at ambient temperature and pressure, along with a simplified production process and lower cost of hydrogen production. Full article

Background/Objectives: Hydroxyapatite (HAp)-based implants and HAp–titanium (HApTi) composites are widely used in orthopedic and dental applications, but their long-term success is limited by peri-implant bone loss. Local delivery of osteoactive molecules from implant surfaces may enhance osseointegration and reduce periprosthetic osteolysis. This study combined in silico modeling and experimental assays to compare calcium fructoborate (CaFb), sodium alendronate, and calcium alendronate as functionalization agents for HAp and HApTi implants. Methods: Molecular docking (AutoDock 4.2.6) and 100 ns molecular dynamics (MD) simulations (AMBER14 force field, SPC water model) were performed to characterize ligand–substrate interactions and to calculate binding free energies (ΔG_binding) and root mean square deviation (RMSD) values for ligand–HAp/HApTi complexes. HAp and HApTi discs obtained by powder metallurgy were subsequently functionalized by surface adsorption with CaFb or alendronate salts. The amount of adsorbed ligand was determined gravimetrically, and in vitro release profiles were quantified by HPTLC–MS for CaFb and by HPLC after FMOC derivatization for alendronates. Results: CaFb–HAp and CaFb–HApTi complexes showed the lowest binding free energies (−1.31 and −1.63 kcal/mol, respectively), indicating spontaneous and stable interactions. For HAp-based complexes, the mean ligand RMSD values over 100 ns were 0.27 ± 0.17 nm for sodium alendronate, 0.72 ± 0.28 nm for calcium alendronate (range 0.35–1.10 nm), and 0.21 ± 0.19 nm for CaFb (range 0.15–0.40 nm). For HApTi-based complexes, the corresponding RMSD values were 0.30 ± 0.15 nm for sodium alendronate, 0.72 ± 0.38 nm for calcium alendronate and 0.26 ± 0.14 nm for CaFb. These distributions indicate that CaFb and sodium alendronate maintain relatively stable binding poses, whereas calcium alendronate shows larger conformational fluctuations, consistent with its less favorable binding energies. Experimentally, CaFb exhibited the greatest chemisorbed amount and percentage on both HAp and HApTi, followed by sodium and calcium alendronate. HApTi supported higher loadings than HAp for all ligands. Release studies demonstrated a pronounced burst and rapid plateau for both alendronate salts, whereas CaFb displayed a slower initial release followed by a prolonged, quasi-linear liberation over 14 days. Conclusions: The convergence between in silico and adsorption–release data highlights CaFb as the most promising candidate among the tested ligands for long-term functionalization of HAp and HApTi surfaces. Its stronger and more stable binding, higher loading capacity and more sustained release profile suggest that CaFb-coated HApTi implants may provide a favorable basis for future in vitro and in vivo studies aimed at improving osseointegration and mitigating periprosthetic osteolysis, although direct evidence for osteolysis prevention was not obtained in the present work. Full article

Metallic biomaterials play essential roles in modern medical devices, but their long-term performance depends critically on protein adsorption and subsequent cellular responses at material interfaces. This review examines the molecular mechanisms governing these interactions and discusses surface modification strategies for controlling biocompatibility. The physicochemical properties of oxide layers formed on metal surfaces—including Lewis acid-base chemistry, surface charge, surface free energy, and permittivity—collectively determine protein adsorption behavior. Titanium surfaces promote stable protein adsorption through strong coordination bonds with carboxylate groups, while stainless steel surfaces show complex formation with proteins that can lead to metal ion release. Surface modification strategies can be systematically categorized based on two key parameters: effective ligand density (σ_eff) and effective mechanical response (E_eff). Direct control approaches include protein immobilization, self-assembled monolayers, and ionic modifications. The most promising strategies involve coupled control of both parameters through hierarchical surface architectures and three-dimensional modifications. Despite advances in understanding molecular-level interactions, substantial challenges remain in bridging the gap between surface chemistry and tissue-level biological performance. Future developments must address three-dimensional interfacial interactions and develop systems-level approaches integrating multiple scales of biological organization to enable rational design of next-generation metallic biomaterials. Full article

Benzyl 2,4-dichlorophenyl sulfoxide was synthesized both in racemic and in an enantiopure form. This enantiopure sulfoxide is a further successful confirmation of our straightforward protocol to yield easily chiral aryl benzyl sulfoxides. We solved also the crystal structure of racemic benzyl 2,4-dichlorophenyl sulfoxide with a single crystal X-ray diffraction experiment. The main interactions building up the crystal structure were recognized and compared with other similar sulfoxides. Full article

The machining of Ti-6Al-4V thin-walled parts is characterized by high cutting temperatures, significant force fluctuations, and complex thermomechanical coupling. Cryogenic Minimum Quantity Lubrication Technology (CMQL) uses bio-lubricant as the lubrication carrier, combined with the cooling characteristics of cryogenic temperature medium, showing good cooling and lubrication performance and environmental friendliness. However, the cooling and lubrication mechanism of different cryogenic media in synergy with bio-lubricants is still unclear. This paper establishes convective heat transfer coefficient and penetration models for cryogenic media in the cutting zone, based on the jet core theory and the continuum medium assumption. The model results show that cryogenic air has a higher heat transfer coefficient, while cryogenic CO₂ exhibits a better penetration ability in the cutting zone. Further milling experiments show that compared with cryogenic air, the average temperature rise, average cutting force and surface roughness of workpiece surface with cryogenic CO₂ as cryogenic medium are reduced by 23.6%, 32.8%, and 11.8%, respectively. It is considered that excellent permeability is the key to realize efficient cooling and lubrication in the cutting zone by Cryogenic CO₂ Minimum Quantity Lubrication Technology. This study provides a theoretical basis and technical reference for efficient precision machining of titanium alloy thin-walled parts. Full article