Search Results (393)

Background: Adhesive indirect restorations have become increasingly common in daily clinical routine in most dental practices. Before etching and adhesive application, a sandblasting procedure is essential to clean and increase the microporosity of the surface. Air abrasion with aluminum oxide particles significantly improves the bond strength. However, this procedure may have some limitations, such as the presence of powder particles. Recently, the Er:YAG laser in QSP mode has been proposed for conditioning build-ups prior to adhesive cementation. The aim of this study was a retrospective analysis of adhesive indirect restoration in which build-up was conditioned or using a traditional sandblaster with alumina powder or using the Er:YAG laser in QSP mode. Methods: 187 posterior indirect adhesive restorations were cemented using two different conditioning techniques: in 96 cases (51.34%) build-up conditioning was performed using an intraoral sandblaster with alumina oxide (Microetcher CD, Kavo, Biberach, Germany); in 91 cases (48.66%) build-up conditioning was performed using the Er:YAG laser (Fotona LighWalker^®, Ljubljana, Slovenia) in QSP modality (1 W, 10 Hz, 100 mJ). The clinical efficacy of the two techniques was evaluated and compared, assessing the occurrence of complications such as debonding, fracture, secondary leakage, and hypersensitivity over time. Results: The frequency of secondary complications was very low in both groups. Only one case of debonding and one case of restoration cracking was observed in the sandblasting group, with none in the laser group (p = 0.329). Secondary caries occurred in both groups. A difference was observed in postoperative hypersensitivity: 6% in the sandblasting group and 1% in the laser group (p = 0.064). The Kaplan–Meier curves of the two conditioning techniques showed comparable survival over time (Log-rank test χ² = 2.4864/p = 0.1148). The mean follow-up was 30 months. Conclusions: The success rates of these restorations are very high if adhesive cementation steps are properly followed. Conditioning the build-up before etching is essential. Among these, the Er:YAG laser in QSP mode seems to provide excellent results in the absence of dust and smear layer. Recurrence rates of complications such as decementation, leakage, and cracking resulted in less than 1%. Furthermore, it is interesting to note that using the laser to condition the build-up appears to reduce the recurrence of post-cementation hypersensitivity. These data require confirmation through prospective clinical trials. Full article

This study evaluated the effect of incorporating chia seed gel powder (CSGP) as a natural, clean-label stabilizer on the physicochemical, functional, microbiological, microstructural, antioxidant, and sensory properties of probiotic low-fat yogurt (PLFY) during 21 days of refrigerated storage. Six formulations were prepared using 0–2.5% CSGP, including Control (0% CSGP), YOG1 (0.5% CSGP), YOG2 (1.0% CSGP), YOG3 (1.5% CSGP), YOG4 (2.0% CSGP), and YOG5 (2.5% CSGP). Results showed that increasing CSGP levels noticeably enhanced the total solids, protein content, viscosity, hardness, and water-holding capacity of the PLFY (p < 0.05), while consistently reducing syneresis. Antioxidant activity also rose with higher CSGP concentrations, with YOG5 exhibiting the greatest DPPH scavenging activity (35.12%). Confocal laser scanning microscopy revealed a denser and more uniform protein network in PLFY fortified with CSGP, consistent with rheological measurements showing increased storage (G′) and loss (G″) moduli. Probiotic viability significantly increased (p < 0.05) in CSGP-added samples, indicating a potential prebiotic effect of CSGP. Sensory results demonstrated that although higher CSGP levels slightly darkened the yogurt color, body, texture, flavor, and total sensory scores improved markedly, with YOG5 gaining the highest total score (81.77). The results demonstrate that CSGP acts as a highly effective, multifunctional ingredient that enhances texture, stability, probiotic viability, and antioxidant capacity, making it a strong clean-label candidate for developing high-quality, functional probiotic low-fat yogurt. Full article

Urban pollution—especially SO₂ and particulate matter—rapidly darkens and degrades outdoor-exposed wall paintings due to soiling. Laser cleaning has emerged as a cutting-edge solution, offering selective removal of contaminant layers while preserving the integrity of the underlying materials. This study explores the performance of a 355 nm Nd:YAG laser in cleaning artificially aged paint mock-ups coated with real diesel soot and exposed to an accelerated aging test with SO₂ exposure. Traditional mineral pigments—silicates (Egyptian blue, ultramarine blue, and green earth), oxides (chromium green, mars red), and a sulphide (cinnabar)—were applied following fresco and secco (egg yolk) techniques, allowing researchers to uncover how pigment chemistry and binders affect laser sensitivity. Damage thresholds were first determined for each pigment and painting technique via digital photography, stereomicroscopy, and colour spectrophotometry. Cleaning efficacy was then assessed by stereomicroscopy, colour spectrophotometry, Fourier-transform infrared spectroscopy, and scanning electron microscopy. The results revealed clear patterns: silicate pigments exhibit stability under laser irradiation, enabling safe cleaning, whereas mars red and cinnabar remain highly sensitive regardless of the technique. Generally, secco paintings were more susceptible to laser radiation than fresco. These finding provide practical guidance for optimising laser-cleaning protocols while safeguarding the delicate surfaces of historic wall paintings. Full article

Molten salt, as a phase change heat storage material, can be used to mitigate the volatility of clean energy. Increasing the specific heat of molten salts can help to increase heat storage density and reduce costs. In this study, nanoparticles with different potentials were prepared and doped into Solar Salt (NaNO₃-KNO₃). The modification results of the nanoparticles were evaluated by transmission electron microscopy, energy dispersive X-ray spectroscopy and infrared spectroscopy, and the modification process was analyzed by density functional theory. The specific heat, thermal diffusion coefficient, melting point, latent heat of the composites and their variation mechanism were analyzed using synchronized thermal analyzer, laser flash analyzer and scanning electron microscope. It was found that acidification was able to modify the SiO₂ nanoparticles and that the higher the acidity, the more the negative charge of the nanoparticles was neutralised. A 25.8% decrease in zeta potential to −23.17 mV was observed for the nano-SiO₂ after treatment with HCl at pH 1, compared to the non-acidified sample. The microelectric field generated by the charged nanoparticles affects the thermophysical properties such as the specific heat of the molten salt-nanoparticle composites, with one of the samples having the largest specific heat (1.79 J/(g·K)) and thermal diffusion coefficient (0.94 mm²/s), which were increased by 13.3% and 14.6%, respectively, compared to the Solar Salt. This study attributes the alterations in thermophysical properties to the variation in ion separation distance induced by the charge on nanoparticles. Full article

Silicon nanowires (SiNWs) fabricated by Ag-assisted metal-assisted chemical etching (MACE) exhibit excellent light-trapping performance, yet their fragile high-aspect-ratio morphology severely limits reliable metallization in photovoltaic devices. Conventional electrode deposition methods often fail on dense SiNW arrays due to poor mechanical stability of the nanowire tips, leading to delamination, inhomogeneous coverage, and high contact resistance. In this work, we introduce a maskless laser-based truncation technique that selectively shortens MACE-derived SiNWs to controlled residual heights of 300–500 nm exclusively within the regions intended for electrode formation, while preserving the full nanowire morphology in active areas. A detailed parametric study of laser power, scanning speed, and pulse repetition frequency allowed the identification of an optimal processing window enabling controlled tip melting without damaging the nanowire roots or the crystalline silicon substrate. High-resolution SEM imaging confirms uniform planarization, well-preserved structural integrity, and the absence of subsurface defects in the laser-processed tracks. Optical reflectance measurements further demonstrate that introducing 2% and 5% truncated surface fractions—corresponding to the minimum and maximum metallized front-grid coverage in industrial Si solar cells—results in only a minimal reflectance increase, preserving the advantageous the light-trapping behavior of the SiNW texture. The proposed laser truncation approach provides a clean, scalable, and industrially compatible route toward creating electrode-ready surfaces on nanostructured silicon, enabling reliable metallization while maintaining optical performance. This method offers strong potential for integration into silicon photovoltaics, photodetectors, and nanoscale electronic and sensing devices. Full article

To address the issues of insufficient responsivity and low imaging contrast of carbon-based HGFET high-sensitivity short-wave infrared (SWIR) detectors under low-light conditions, this paper proposes a high-sensitivity and high-contrast image enhancement algorithm for low-light detection, with FPGA-based hardware verification. The proposed algorithm establishes a multi-stage cooperative enhancement framework targeting key challenges such as low signal-to-noise ratio (SNR), high dark-state noise, and weak target extraction. Unlike traditional direct enhancement methods, the proposed approach first performs defective row-column correction and background noise separation based on dark-state data, which provides a clean foundation for signal reconstruction. Furthermore, an adaptive gamma correction mechanism based on image maximum value is introduced to avoid unnecessary nonlinear transformations in high-contrast regions. During the contrast enhancement stage, an exposure-constrained adaptive histogram equalization strategy is adopted to effectively suppress noise amplification and saturation in low-light scenes. Finally, an innovative dual-mode threshold selection method based on image variance is proposed, which can dynamically integrate the OTSU algorithm with statistical moment analysis to ensure robust background noise separation across both high- and low-contrast scenarios. Experimental results demonstrate that the proposed algorithm significantly improves target contrast in infrared images while preventing detail loss due to overexposure. Under microwatt-level laser power, background noise is effectively suppressed, and both imaging quality and weak target detection capability are substantially enhanced. Full article

In this study, a kW-level high-power Nd:YAG nanosecond laser was adopted to eliminate a corrosion layer on a 304L stainless steel (SS304L) surface. Four different laser cleaning (LC) processes with various hatch distances and loop counts were adopted. The energy-dispersive X-ray spectroscopy (EDX) analysis revealed that the corrosion layer was successfully eliminated via the LC process. However, the electron probe X-ray microanalysis (EPMA) analysis confirmed that a Cr-based oxide layer with a thickness of a few micrometers had developed on the surface of SS304L by the LC process. Moreover, Cr-depleted regions were generated in the subsurface owing to the Cr consumption for oxide layer development. The surface temperature during the LC process strongly affected the thickness of oxide layers. The oxide layer and Cr-depletion formation can affect the subsequent manufacturing processes, including welding and molding. Moreover, those can influence the materials’ properties themselves, where the laser-cleaned workpieces may be used. Therefore, it is critical to characterize the relation between LC process parameters and microstructural alteration. Full article

This study investigates the effects of laser and cryogenic (dry ice) surface treatments on enhancing surface characteristics of Ti-6Al-4V titanium alloy components produced using the Selective Laser Melting (SLM) technique. Components produced via additive manufacturing often exhibit increased surface irregularities and residual unmelted powder, which can deteriorate their mechanical strength and resistance to corrosion. In this study, SLM samples manufactured with two laser powers (176 W and 220 W) were subjected to laser cleaning and dry ice blasting under various process parameters. Surface topography and morphology analyses were performed. The obtained results showed that both methods improved surface uniformity and removed contaminants. Dry ice treatment effectively removed loose powder particles and impurities without causing structural changes—the best results were obtained at a pressure of 10 bar. Laser treatment, depending on the focal length, produced varying degrees of surface remelting—from gentle smoothing (500 mm) to intensive thermal effects and microcracks (250 mm). The research confirmed that cryogenic cleaning is an environmentally friendly and safe post-processing method, while laser cleaning enables deeper surface structure modification, requiring further optimization. Full article

The denim production is among the most polluting processes in textiles due to its high consumption of water, energy, and chemicals. This study presents a Systematic Literature Review (PRISMA 2020) on sustainable treatments applied to denim, with emphasis on their environmental impacts, evaluation methodologies, and main implementation challenges. A total of 26 open-access articles published between 2020 and 2024 in Scopus and Web of Science, in English and Spanish, were analyzed. The most relevant treatments include enzymes, ozone, laser, nebulization, and recycled materials, which report reductions of up to 60% in water consumption, decreased use of chemicals, lower CO₂ emissions, and reduced solid waste generation, consolidating them as viable alternatives to conventional methods. Life Cycle Assessment (LCA) emerges as the main evaluation tool, although its application remains partial and inconsistent. The findings highlight the need to standardize methodologies and integrate economic, social, and regulatory dimensions in order to foster a sustainable transition aligned with the Sustainable Development Goals. Full article

Femtosecond laser has been widely utilized in functional microstructural surfaces for applications such as anti-reflection, radiative cooling, and self-cleaning. However, achieving high-efficiency manufacturing of high-consistency functional microstructures (with feature sizes ~1 μm) over large areas remains a challenge. Here, we report a femtosecond laser temporal and spatial modulation technique for fabricating large-area anti-reflective microholes on magnesium fluoride (MgF₂) windows. The beam was transformed into a Bessel beam to extend the Rayleigh length, enabling the fabrication of microhole arrays with sub-micron precision and surface roughness variations within 10 nm over a 6 μm focal position shift range (5–11 μm). By modulating MHz burst pulses, the aspect ratio of the microholes was increased from 0.3 to 0.7 without compromising a processing speed of 10,000 holes per second. As a proof of concept, large-area anti-reflective microholes were fabricated on a 20 mm × 20 mm surface of the MgF₂ window, forming a nanoscale refractive index gradient layer and achieving a transmittance increase to over 98%. This method provides a feasible solution for the efficient and high-consistency manufacturing of functional microstructures over large areas. Full article

Archeological ceramics represent values that necessitate preservation from various factors of deterioration. Cleaning processes are beneficial in the preservation of these ceramics. An abundance of cleaning technique and process information exists within the literature. This study examines the current state of both traditional and advanced cleaning techniques employed for archeological ceramics. The review discusses a wide range of commonly used cleaning techniques, including mechanical, dry and wet processes, as well as chemical approaches. Additionally, more recent laser, plasma, and biocleaning methods are discussed. The effectiveness of these techniques is examined, as well as potential damage or surface modifications to the ceramics. The selection of a cleaning method for ceramics depends on the specific characteristics of the ceramic (i.e., porosity, glaze, slip red-slipped, etc.), its state of conservation, and the nature and thickness of the fouling or encrustations. Careful selection and testing of chemical solutions are crucial to prevent damage. While chelating agents like EDTA effectively dissolve crusts and salts, uncontrolled application can weaken ceramic structures. Laponite, natural clay minerals, resins and organic gels (xanthan gum, agar, cellulose powder) are effective in removing contaminants from the surfaces of without causing damage. Environmentally friendly methods such as biocleaning, Pulsed Laser Cleaning, and plasma are effective but underutilized, requiring further investigation. This review emphasizes the growing potential of sustainable and non-invasive methods to complement or replace traditional approaches. Its main contribution lies in providing a critical synthesis that bridges conventional and innovative techniques, outlining research gaps for more effective and eco-responsible conservation of archeological ceramics. Full article

A cost-effective laser marker was employed to fabricate a superhydrophilic, photocatalytic Mg-Ti-based surface on glass under ambient conditions. The photocatalytic layer was first deposited via laser processing, followed by partial laser etching to generate micro/nanostructures on the surface. This method preserves partial photocatalytic functionality while enhancing surface roughness and introducing unique nanostructures, enabling the sample to simultaneously exhibit antifogging, self-cleaning capabilities, and high light transmittance. The optimal sample was achieved by tuning laser processing parameters, including repetition rate and scanning hatch distance. It maintained a water contact angle (WCA) of 0° after 15 days of outdoor exposure, which only increased to 21.2° after 30 days. In comparison, the WCA of reference glass increased from an initial 23.3° to 63.9° over the same period. Furthermore, the amount of dust accumulated on the optimal sample was significantly lower—by up to 43%—than that on the reference glass over one month under both indoor and outdoor conditions. After a single spray cleaning, the dust removal efficiency of the indoor-stored optimal sample reached 70%, which was 56% higher than that of the reference. For samples stored outdoors, a single spray removed 67% of the dust from the optimal surface, compared to only 26% for the reference, highlighting its excellent self-cleaning performance. Additionally, the optimal also showcased remarkable antifogging property, which had been maintained over the one-month exposure period without visible degradation. Moreover, the optimal sample exhibited a 2% enhancement in broadband light transmittance across the 400–1000 nm wavelength range, demonstrating strong potential for photovoltaic applications. The simultaneous achievement of antireflection, antifogging, and self-cleaning performance under both indoor and outdoor conditions over a one-month period has rarely been reported in the literature. Full article

Organic contaminants on optical components critically impair intense laser systems. Oxygen plasma cleaning is a promising non-contact method, yet the mechanism by which the initial kinetic energy of reactive oxygen species assists chemically driven removal remains unclear. This study employs ReaxFF molecular dynamics to elucidate how reactive oxygen species chemically decompose dibutyl phthalate and how kinetic energy assists chemical reactions by enhancing transport, penetration, and energy transfer. While the core removal mechanism is chemical, kinetic energy promotes plasma-contaminant encounters and facilitates access to otherwise sluggish pathways. The results show that kinetic energy is a key promoter that enhances chemical decomposition, with the contaminant decomposition rate enhanced by up to 1310% and residues reduced by 81.13% compared to pure chemical reactions. This study identifies and quantifies two dominant reaction pathways (butyl chain cleavage & benzene ring cleavage). The analysis of diffusion and energy transfer reveals that higher kinetic energy improves reactive oxygen species transport, enables deeper penetration, and selectively activates specific reaction pathways by overcoming energy barriers. Synergy with flux, dose, and temperature is also demonstrated. This work provides atomic-level insights into kinetic promotion mechanisms, supporting optimized plasma cleaning processes and contributing to the performance stability and operational longevity of intense laser systems. Full article

Surface roughness influences biofilm adhesion on denture base materials, impacting oral health. Despite advances in polymeric denture materials, the effects of common cleaning protocols on their surface texture remain inadequately characterized. This study investigated the influence of toothbrush abrasion on the surface texture of dimethyl methacrylate-based (DMA, printed: V-Print dentbase), polymethyl methacrylate (PMMA, milled: VITA Vionic Base, pressed: IvoBase Hybrid), polyamide (PA, pressed: Bre.flex), and polyether ether ketone (PEEK, milled: Juvora Disc). The specimens were fabricated as polished discs. The Vickers and Martens hardness, indentation modulus, elastic and plastic part of indentation work, and indentation creep were determined. Toothbrushing simulation and surface texture analysis were conducted in three steps: 1800, 1800, and 3600 cycles using water, dish detergent, or toothpaste slurry. The surface texture parameters Sa, Sal, Sdr, Sku, and Ssk were determined using confocal laser scanning microscopy and suitable filtering (S-F and S-L surface). Sa, Sal, and Sdr showed significant changes depending on the choice of medium and the material used. The duration had a small effect (three-way ANOVA; all p < 0.001). DMA showed minor surface changes. Milled and pressed PMMA exhibited similar surface deformities due to wide valleys that were not considered critical for biofilm adhesion. PA showed the lowest and PEEK the highest Vickers and Martens hardness. However, both PA and PEEK exhibited surface changes that could promote biofilm development. These findings suggest that denture cleaning recommendations should remain material-specific. Regular surface inspections and repolishing are necessary to reduce the risk of biofilm formation on PA or PEEK-containing dentures. Full article

Superhydrophobic surfaces, characterized by water contact angles greater than 150°, have attracted widespread interest due to their exceptional water repellency and multifunctional applications. However, traditional fabrication methods often rely on fluorinated compounds and petroleum-based polymers, raising environmental and health concerns. In response to growing environmental and health problems, recent research has increasingly focused on developing green superhydrophobic surfaces, employing eco-friendly materials, energy-efficient processes, and non-toxic modifiers. This review systematically summarizes recent progress in the development of green superhydrophobic materials, focusing on the use of natural substrates such as cellulose, chitosan, starch, lignin, and silk fibroin. Sustainable fabrication techniques, including spray coating, dip coating, sol–gel processing, electrospinning, laser texturing, and self-assembly, are critically discussed with regards to their environmental compatibility, scalability, and integration with biodegradable components. Furthermore, the functional performance of these coatings is explored in diverse application fields, including self-cleaning, oil–water separation, anti-corrosion, anti-icing, food packaging, and biomedical devices. Key challenges such as mechanical durability, substrate adhesion, and large-scale processing are addressed, alongside emerging strategies that combine green chemistry with surface engineering. This review provides a comprehensive perspective on the design and deployment of eco-friendly superhydrophobic surfaces, aiming to accelerate their practical implementation across sustainable technologies. Full article