Search Results (772)

Femtosecond laser processing enables spatially controlled modification of the structure, composition, and functionality of advanced materials through highly localized energy deposition and laser–matter interaction mechanisms. This review discusses the role of ultrafast laser irradiation in the engineering of oxide-based functional systems, including functional oxides, oxide-containing layers, interfaces, and heterogeneous structures whose properties are substantially determined by an oxide component. The mechanisms governing laser-induced oxidation, phase transformation, elemental redistribution, defect generation, and hierarchical micro-/nanostructure formation are considered. Particular attention is given to the ability of femtosecond laser processing to create surfaces with tailored interactions with light, liquids, biological environments, and external stimuli, enabling responsive devices and advanced manufacturing strategies. Laser-modified oxide layers and nanostructured interfaces are analyzed as pathways for controlling surface energy, optical properties, chemical activity, and functional response. The relationship between laser-generated architectures and their applications in sensing, actuation, wetting control, and multifunctional systems is discussed. By connecting ultrafast laser surface engineering with emerging 4D manufacturing concepts, this review highlights femtosecond laser technologies as a versatile platform for designing systems with spatially programmed functionality and, where stimulus-dependent behavior is demonstrated, time-dependent performance. Such approaches provide opportunities for integrating adaptive oxide-based functional systems into advanced manufacturing. Full article

Background: The clinical translation of cell-based therapies for knee articular cartilage repair is fundamentally restricted by the severe biological unpredictability of autologous cell sources, inherent manufacturing bottlenecks, and the rapid phenotypic dedifferentiation of cells expanded in conventional 2D monolayers. To overcome these translational hurdles, this study engineered a scaffold-free, 3D formulation of highly characterized allogeneic FE002-Cart chondroprogenitor spheroids. Methods: We systematically investigated the specific microenvironmental cues and Good Manufacturing Practice (GMP) formulation parameters required to direct functional chondrogenesis. The structural and biochemical performance of this allogeneic formulation was benchmarked against multiple primary adult autologous chondrocyte types. Finally, we evaluated the phenotypic resilience of the microtissues in simulated osteoarthritic (OA) environments and investigated both short-term liquid storage and advanced terminal preservation strategies to establish off-the-shelf logistical viability. Results: Precise microenvironmental regulation proved to be a critical biological prerequisite. The synergistic combination of physiological hypoxia (2% O₂) and stringent glucocorticoid limitation (10 nM dexamethasone) induced robust glycosaminoglycan (GAG) deposition and a > 200-fold upregulation of ACAN and COL2, while suppressing the terminal hypertrophic drift observed in adult chondrocytes. Benchmarking revealed that the allogeneic FE002-Cart formulation substantially mitigates the profound morphological and biochemical unpredictability inherent to adult autologous cell sources. Furthermore, the scaffold-free spheroid geometry yielded a 10-fold increase in GAG production per cell compared to traditional matrix-seeded (MACI) platforms. Transitioning to a GMP-compatible manufacturing process revealed extreme cellular sensitivities; excipients within standard pharmaceutical-grade dexamethasone severely aborted chondrogenic differentiation, emphasizing the necessity of rigorous raw-material qualification. Functionally, the 3D architecture acted as a protective physical shield, sustaining high cellular viability when subjected to severe inflammatory stress and 100% OA patient synovial fluid. Logistically, the viable spheroids maintained matrix integrity and inter-spheroid fusion potential for up to 7 days at ambient temperature in transport medium. Finally, advanced spheroid preservation via lyophilization and high-dose gamma irradiation eliminated biological viability but successfully transitioned the microtissues into highly organized, terminally irradiated matrices capable of heterologous in vitro structural merging. Conclusions: These findings define the critical biological thresholds for manufacturing, demonstrate the enhanced in vitro biosynthetic efficiency of 3D allogeneic microtissues compared to specific autologous and matrix-dependent baselines, and establish a highly practical, off-the-shelf logistical framework for the regenerative treatment of large knee chondral defects. Full article

Ultrafast laser processing enables the creation of functional surfaces in metals, semiconductors, ceramics, polymers and other materials through spatially controlled nonequilibrium energy deposition. However, the resulting surface functionality cannot be explained solely by laser parameters or geometric features. Femtosecond irradiation induces a sequence of coupled processes, including nanoscale structuring, phase transformation, chemical modification, defect formation, and relaxation, which define the final surface state. This review introduces the Surface-by-Design concept, where functional surfaces are considered as engineered material states formed through controlled laser–matter interaction rather than as predefined patterns. Representative examples including laser-induced periodic surface structures, hierarchical micro/nanotextures, modified oxide layers, and laser-generated functional interfaces are analyzed in relation to wettability, tribological behavior, corrosion resistance, optical response, and other properties. The review further examines how advanced characterization, digital engineering, beam shaping, in situ diagnostics, and data-driven methods contribute to controlling surface evolution. Remaining challenges include reproducibility, scalability, and reliable prediction of functional behavior during service conditions. Future progress in femtosecond laser surface engineering will depend on the ability to control not only the generated morphology but also the evolving structural and physicochemical state of functional interfaces. Full article

A homogeneous photocatalyst on a stable substrate is required for photocatalytic reactors in wastewater treatment. ZnO films were synthesized on stainless steel prepared by the spray pyrolysis technique at different deposition temperatures (350 to 500 °C in steps of 50 °C). Scanning electron microscopy showed microflowers formed by nanopetals with an average size of 2 μm. The ZnO wurtzite structure and its defects were studied by Raman spectroscopy, X-ray diffraction, diffuse reflectance, and photoluminescence spectroscopy. A deposition temperature of 400 °C was chosen due to the presence of a higher number of vibrational modes, better distribution of microflowers, smaller crystallite size and a higher number of defects than the other options. Lanthanides were incorporated into ZnO by solution spraying, and then thermal treatment was performed at 600 °C. The photocatalytic evaluation of ZnO showed the best photocatalytic activity under UV light at 365 nm with a 69.34% degradation efficiency at 120 min. Photocatalytic activity toward methylene blue degradation was enhanced in ZnO:Ce³⁺ (2 and 4 atom%) and ZnO:Nd³⁺ (0.05 and 2 atom%) samples, achieving degradation efficiencies above 90% within 30 min of UV–visible light irradiation. Full article

Refractory high-entropy and compositionally complex alloys are routinely compared by nominal composition and as-processed phase, yet processing changes the material that is actually tested. This is a critical, mechanism-led narrative review rather than a systematic review; the databases, complete search strings, screening sequence, inclusion and exclusion criteria, and evidence-grading rubric are reported so that coverage and selection bias can be assessed independently. This review synthesizes 186 publications around the NbTaV compositional core and compares alloys through directly measurable features of the processed state: interstitial content, local chemical order, grain-boundary chemistry, defect and grain architecture, phase morphology, compositional gradients and surfaces. Every source is assigned to a compositional tier and graded along four evidence axes: 96 of the 186 sources report Nb–Ta–V-containing states (Tier I), 58 are body-centered cubic refractory comparators (Tier II) and 32 are transferred-mechanism analogues (Tier III), and only 14 Tier I sources supply direct tensile, fracture or tensile-creep measurements. This asymmetry, rather than any disagreement between compositions, is the field’s binding evidence constraint. Direct tensile, fracture, and creep measurements are kept separate from compression, hardness, calculation, and screening evidence. This separation reconciles observations that otherwise appear to conflict: oxygen can strengthen or embrittle; lattice distortion can raise strength while lowering dislocation mobility; local order can harden the alloy, redirect defects or precede decomposition; and second phases help only within morphology- and service-specific compatibility windows. The strongest tensile behavior is obtained when mobile plasticity carriers are preserved, and interstitials, interfaces and phase continuity are simultaneously controlled. High-temperature, environmental, and irradiation performance depend additionally on the transition from the as-manufactured condition to the state that evolves during service. Quantitative matching tolerances for the convergent-state falsification test, service-condition-specific validation hierarchies, ordinal scoring rules for the phase-compatibility map, and a source-level audit of every quantitatively compared value are provided so that the framework can be tested and the synthesis independently checked. Full article

Zinc oxide (ZnO) is a wide-bandgap semiconductor with important optoelectronic, photonic, and radiation-related applications. In this work, hydrothermally grown ZnO bulk single crystals were irradiated with fast neutrons and characterized using low-temperature photoluminescence (PL) spectroscopy to investigate irradiation-induced changes in the Ga-related donor-bound exciton (I₈). The Zn-polar surfaces were exposed to fast neutrons for irradiation durations of 2 and 5 min. The PL measurements showed a reproducible enhancement of the Ga-related I₈ emission intensity, with increases of approximately 33% after 2 min and 82% after 5 min relative to the unirradiated reference crystal. The selective enhancement of the I₈ emission is consistent with increased Ga-related donor activity associated with the proposed Zn-to-Ga neutron transmutation mechanism, although irradiation-induced defect formation and redistribution may also contribute to the observed optical response. Under the irradiation conditions investigated, fast-neutron exposure produced substantial enhancement of the I₈ emission within only a few minutes. However, direct quantitative comparison with previously reported slow-neutron irradiation should be interpreted with caution because the two studies employed different neutron energies, fluences, and irradiation conditions. These findings demonstrate the potential of fast-neutron irradiation for modifying the low-temperature optical response of hydrothermally grown ZnO and provide a foundation for future investigations of neutron-induced defect and donor engineering in wide-bandgap oxide semiconductors. Full article

Background: Surgical removal of jaw cysts may result in bone defects that compromise local structural integrity and delay spontaneous regeneration. Photobiomodulation (PBM) has been proposed as a minimally invasive intraoperative adjunct capable of modulating osteogenic activity; however, translational evidence derived from freshly harvested human jawbone tissue remains limited. Objective: This study evaluated the effects of an intraoperative 980 nm PBM protocol on early osteogenic activity, osteoblast-like cell abundance, morphometric outcomes, and cell viability in primary human jawbone explants obtained during cystectomy. Materials and Methods: A comparative translational ex vivo study was conducted using cortical bone explants harvested from 40 patients undergoing surgical treatment of medium- to large-sized maxillary or mandibular cystic lesions. For each patient, one explant was exposed immediately after harvesting to pulsed 980 nm laser irradiation (20 J total energy; 40 J/cm² fluence), whereas the paired explant served as an untreated control. Explants were cultured using a primary outgrowth technique and subjected to osteogenic induction for 14 days. Osteogenic activity was evaluated by immunofluorescence staining for alkaline phosphatase (ALPL) and osteocalcin (OCN), followed by confocal microscopy and quantitative morphometric analysis. Cell viability was assessed using a live/dead fluorescence assay. Results: Viable cultures were successfully established from 34 patients (85% experimental yield). PBM-treated explants exhibited significantly greater osteoblast-like cell counts than paired controls (median: 2820 vs. 1525 cells; p < 0.001), together with greater cumulative osteoblastic area (median: 537,028 vs. 325,166 relative units; p < 0.001) and higher osteoblastic area occupancy (median: 19.00% vs. 11.75%; p < 0.001). Immunofluorescence analysis demonstrated qualitatively stronger ALPL and OCN expression in PBM-treated cultures. Cell viability did not differ significantly between paired PBM-treated and control cultures (Wilcoxon signed-rank test, p = 0.18). Conclusions: In this comparative ex vivo model, intraoperative 980 nm PBM significantly enhanced early osteogenic activity and increased osteoblast-like cellular abundance in human jawbone explants while maintaining cellular viability. These findings provide translational support for further investigation of PBM as a biostimulatory adjunct to enhance bone regeneration following cyst surgery. Full article

This study investigated twelve gem-quality color-change fluorite specimens exhibiting a purple–blue gradient from Nova Era, Brazil, using colorimetry, Raman spectroscopy, UV-Vis spectroscopy, photoluminescence spectroscopy, EDXRF, and DiamondView imaging to explore the relationship between color depth and coloration mechanism. Raman spectroscopy further revealed enhanced defect-related peaks in dark samples, indicating cumulative irradiation-induced lattice damage. EDXRF analysis revealed that the radioactive element Th was detected exclusively in dark samples, with the darkest specimen reaching 0.184 wt.% Th, confirming that long-term Th-induced irradiation is the primary driver of color deepening. In UV-Vis spectra, the ~583 nm plasmon resonance absorption band of calcium colloids progressively red-shifted and broadened with increasing color depth, indicating elevated colloid concentrations and enhanced aggregation that directly intensify body color. DiamondView fluorescence weakened with deepening color, attributed to the quenching effect of calcium colloids. Photoluminescence spectra showed that the Eu²⁺ emission peak intensified in dark samples, while the broad 700–900 nm emission band systematically blue-shifted, reflecting differential responses of luminescence centers to radiation damage. This study provides non-destructive spectroscopic criteria for the fluorite color-change mechanism without relying on micro-area compositional analysis, establishing an analytical paradigm linking color gradients with spectral characteristics. Full article

Semiconductor-based photocatalytic water splitting is a promising pathway for sustainable hydrogen production; however, the reported performance depends not only on the intrinsic properties of the photocatalyst but also on reactor configuration and operating conditions. This systematic technical review examines the interplay between nanostructured semiconductor photocatalysts and the principal engineering variables governing photocatalytic hydrogen evolution. Particular attention is given to particle size, morphology, surface area, defect density, heterojunction design, cocatalyst incorporation, aggregation, and catalyst immobilization, as well as their interaction with reactor geometry, optical path length, photon distribution, catalyst loading, working volume, pH, sacrificial agents, mixing, thermal control, gas purging, and product quantification. The reviewed evidence indicates that these material and reactor parameters jointly determine light absorption, charge-carrier separation and transfer, suspension turbidity, mass transport, catalyst recovery, stability, and the measured hydrogen evolution rate. Batch slurry reactors remain the most widely used laboratory configuration, whereas annular, flat-panel, microreactor, fixed-bed, continuous-flow, and photofluidized systems offer specific advantages for photon utilization, catalyst reuse, product removal, and scale-up. The review also emphasizes the need to distinguish overall water splitting from sacrificial-agent-assisted hydrogen evolution. Standardized reporting of photocatalyst properties, irradiance, spectral distribution, illuminated area, reactor dimensions, reaction atmosphere, and gas-analysis procedures is essential to improve reproducibility and enable reliable comparisons among nanostructured photocatalytic systems. Full article

Chromium coatings with excellent corrosion resistance and strong Zr interfacial bonding are economical candidates for accident-tolerant fuel claddings. Irradiation-triggered elemental interdiffusion and interfacial voids severely degrade their service reliability. Ni alloying was introduced into the Cr matrix to obtain composite coatings with improved mechanical properties and irradiation resistance. CrNi coatings with different Ni contents were deposited using magnetron sputtering, whose microstructural features, phase composition, mechanical properties and irradiation behavior were comprehensively characterized by XRD, SEM, TEM and mechanical measurements. The pristine CrNi coatings display compact and uniform microstructural morphologies. Increasing Ni concentration significantly refines the columnar grain architecture and diminishes grain dimensions. Post-irradiation microstructural characterization reveals distinct structural evolution features of CrNi coatings with different Ni contents. Pure Cr and low-Ni coatings present enhanced XRD diffraction intensities and contain high-density irradiation-induced dislocation loops. The 27 at.% Ni coating after irradiation is indicative of irradiation-triggered local recrystallization and defect annihilation. Mechanical tests confirm that moderate Ni alloying (~17 at.%) achieves improved resistance to irradiation-induced hardening through solute–defect interaction effects, whereas excessive Ni (~27 at.%) degrades mechanical properties owing to aggravated lattice disorder, increased free volume, and soft Ni-phase dilution effects. Full article

The rapid development of Generation IV nuclear reactors has imposed stringent requirements on structural materials, demanding excellent irradiation resistance to withstand long-term exposure to complex radiation environments, including neutron and ion irradiation. Under irradiation, a large number of defects are generated inside materials via displacement cascades, and the dynamic evolution of these defects gradually leads to macroscopic property deterioration, potentially triggering major accidents such as equipment failure and even posing system safety hazards. Thus, understanding the law of defect evolution in materials under irradiation and exploring the microscopic mechanism of irradiation damage are core prerequisites for material service life prediction, radiation resistance optimization, and safety risk assessment. In recent years, computational simulation, leveraging its unique advantages in multiscale and multiphysics coupling research, has yielded numerous innovative achievements in the irradiation field. This review overviews the progress of computational simulation studies on irradiation damage in nuclear structural materials over the past few decades, focuses on summarizing the “generation-evolution-annihilation” process of irradiation defects, and further discusses the impact of irradiation on the macroscopic mechanical properties of materials. The content and outlook of this review can advance the microscopic-level comprehension of irradiation damage mechanisms in structural materials and provide guidance for the development of a new generation of materials with excellent irradiation resistance. Full article

Antibiotics have been extensively used in medicine and aquaculture, leading to severe environmental contamination. Among them, chlortetracycline (CTC) has attracted considerable attention due to its large consumption and high residual risk. MIL-125(Ti), as a representative titanium-based metal–organic framework, exhibits good structural stability and tunability; however, its intrinsically weak visible-light response and rapid charge recombination limit further photocatalytic applications. To improve its photocatalytic performance, MIL-125 was first synthesized via a hydrothermal method, and then Fe and S species were introduced through a combination of in situ coprecipitation and mild sulfuration, yielding an Fe/S-modified MIL-125 photocatalyst. The introduction of Na₂S induced defect sites and coordinatively unsaturated centers on the MIL-125 surface, while the cooperative participation of Fe species further regulated the surface electronic structure and active-site distribution, thereby enhancing visible-light absorption and interfacial charge transfer. Under AM 1.5 irradiation, the optimized Fe/S-MIL-125 achieved a CTC degradation efficiency of 98.6% within 120 min at an initial concentration of 40 mg L−1. In addition, the material exhibited broad applicability toward multiple antibiotics, with degradation efficiencies exceeding 87% for ciprofloxacin (CIP) and clindamycin (CLI). Cycling tests demonstrated that the catalyst retained high activity after five successive runs, indicating excellent stability. Radical scavenging experiments and ESR analyses revealed that superoxide radicals (·O²⁻) were the dominant reactive species. Overall, the Fe/S-modified strategy significantly enhanced the photocatalytic performance of MIL-125 through defect engineering and interfacial charge regulation, offering a promising approach for the design of MOF-based materials for antibiotic removal. Full article

Radiation-induced defect engineering is an effective approach for modifying the vortex-pinning landscape in high-temperature superconductors, particularly REBCO-coated conductors and Bi-based cuprates. This review critically summarizes the relationship between irradiation parameters, defect morphology, and superconducting performance. The discussion covers point defects, defect clusters, columnar tracks, planar defects, and displacement cascades generated by electrons, gamma rays, light ions, heavy ions, and neutrons. Special attention is given to the dual role of irradiation: moderate defect concentrations can enhance the critical current density by introducing artificial pinning centers, whereas excessive disorder suppresses the superconducting transition temperature and degrades current transport. The review also discusses the relevance of irradiation effects for fusion magnets, space technologies, accelerator systems, and high-field applications. Finally, the review identifies key challenges for future HTS radiation engineering, including cryogenic in situ irradiation, coupled radiation–strain–field experiments, damage metrics beyond dpa, and multi-scale models capable of linking atomic defect production, oxygen disorder, vortex pinning, and macroscopic J_c/T_c degradation. Full article

Silicon carbide (SiC) is the leading wide-bandgap semiconductor material, providing mature doping and device fabrication. Additionally, SiC hosts a multitude of optically active point defects (color centers) and is relevant for many applications in quantum technologies. A crucial step towards harnessing the full potential of the SiC platform includes technologies to create color centers with defined localization and density, e.g., to facilitate their coupling to nano-photonic structures and to observe cooperative effects. Here, silicon vacancy centers and divacancies stand out, as no impurity atom is needed, and high-thermal budget annealing steps can be avoided. We characterize the effect of localized, femtosecond laser irradiation of SiC, investigating surface modifications and photoluminescence, including Raman spectroscopy and optical lifetime measurements. We employ commercial, high-purity, semi-insulating substrates and an industrial-grade laser system to explore broader applicability of the method. As a novel approach, we apply femtosecond laser irradiation to SiC substrates with an epitaxial graphene layer and find that the threshold for photoluminescence due to laser treatment is lowered. Full article

The growing demand for polymer recycling requires effective approaches to improve the performance of recycled materials and expand their practical applications. In this study, electron-beam irradiation was investigated as a method for modifying recycled polyethylene obtained from façade-fastening elements. Virgin PE-80 polyethylene was used as a reference material for comparison. Irradiation was carried out using an ILU-10 electron accelerator (5 MeV) at doses of 95–125 kGy. Structural, morphological, elemental, thermal, crosslinking, and mechanical characteristics were evaluated using FTIR spectroscopy, SEM/EDS analysis, differential scanning calorimetry (DSC), gel fraction determination, and tensile testing according to ISO 527. The results showed that irradiation promotes the formation of a crosslinked network structure in both materials, as confirmed by the increase in gel fraction with increasing dose. For recycled polyethylene, gel fraction values increased from 46.7 to 56.2%, indicating effective radiation-induced crosslinking despite the structural heterogeneity of the material. FTIR analysis revealed the formation of oxygen-containing functional groups associated with radiation-induced oxidation, which was more pronounced in recycled polyethylene due to the presence of pre-existing defects and degradation products. SEM observations revealed increased surface roughness and localized fibrillar features after irradiation, while DSC analysis indicated a decrease in the crystallinity of recycled polyethylene associated with radiation-induced crosslinking and restricted molecular chain rearrangement. Mechanical testing showed an increase in tensile strength and elastic modulus accompanied by a reduction in elongation at break. Among the investigated irradiation doses, 110 kGy provided the most favorable balance between crosslinking efficiency and preservation of structural integrity. These findings demonstrate that electron-beam irradiation is an effective strategy for upgrading recycled polyethylene by improving its mechanical performance while maintaining structural integrity, thereby expanding its potential for reuse in circular economy applications. Full article