Search Results (763)

Contemporary mural paintings contribute a significant part of urban cultural heritage, yet their conservation remains challenging due to the complex materials used and the aggressive conditions of the urban environment. Among the main deterioration factors, vandalic graffiti is particularly problematic, as its removal must be carried out without damaging the original paint layer, which often has a similar chemical composition. In this context, laser cleaning is a promising alternative to conventional mechanical and chemical methods. This study evaluates the effectiveness and selectivity of a nanosecond Nd:YAG laser (1064 nm) for the removal of a blue alkyd graffiti spray paint applied over mock-ups prepared with alkyd and polyvinyl acetate (PVA) paints on concrete substrates. The cleaning results were evaluated by stereomicroscopy, colour spectrophotometry, measurement of static contact angle, profilometry, near-infrared (NIR) hyperspectral imaging, Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS) to assess physical and chemical changes after laser treatment. The results show that the effectiveness and selectivity of the process depend strongly on the chemical composition of both the vandalism layer and the original paint system, highlighting the importance of preliminary material characterisation prior to laser cleaning interventions. Although laser cleaning enabled the partial or substantial removal of the blue alkyd graffiti in all cases, alkyd-based paints exhibited greater resistance to laser irradiation and allowed more effective graffiti removal with fewer surface alterations than PVA-based paints. Among them, the green alkyd paint achieved the highest cleaning efficiency. These results indicate that the interaction between laser radiation and the materials was governed not only by the binder type, but also by the pigment composition and the optical properties of the paint layers. Full article

Afghanistan’s Panjshir Valley is an important emerald-producing region in Asia. In this study, emeralds from Kamar Safid in Southeastern Panjshir were investigated by Fourier-transform infrared (FTIR), Raman spectroscopy, ultraviolet–visible–near-infrared (UV-Vis-NIR) spectroscopy, and laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS). These Kamar Safid emeralds are generally small, light-green-to-green crystals. Microscopic observations revealed abundant acicular and tubular three- or two-phase fluid inclusions, with transparent feldspar-group mineral inclusions. Solid phases in the fluid inclusions commonly consist of carbonate crystals or several transparent halite daughter crystals. FTIR spectra of samples indicated that the absorption of type II H₂O was higher than type I H₂O in the emeralds from Kamar Safid. The UV-Vis-NIR spectra are characterized by Cr- and V-related absorption bands, which are stronger than Fe-related absorptions. LA-ICP-MS results indicate slightly higher V contents and lower Cr contents than emeralds from other Panjshir mining areas. The relatively low total Cr and V contents of Kamar Safid emeralds account for the overall lighter color, suggesting that Cr and V are the principal chromophores, whereas Fe secondarily modifies hue. Rb, Cs, and Sc contents are 6.2–24.3 ppm, 11.9–141.6 ppm, and 92–1461 ppm, with total alkali contents of 4903.10–14,257.18 ppm. Cs-Rb, Cs-Sc, Li-Cs, and Li-Sc binary logarithmic diagrams indicate enrichment in Sc and Rb and depletion in Li and Cs. Full article

The beef industry is interested in quick, non-destructive methods to assess meat quality. This study evaluated the potential of laser-light backscattering imaging (LLBI) for assessing physicochemical properties and oxidative stress-related traits in Arouquesa beef, exploring its applicability as a non-invasive approach for detecting alterations potentially associated with pH. In 34 samples of Longissimus thoracis et lumborum (LTL) muscle from Arouquesa steers, the pH and oxidative stress biomarkers were quantified 24 h post-mortem, and backscatter images were obtained using green and red laser sources, with the areas corresponding to the core, inner ring, and outer ring of the diffusion patterns measured. After 7 days’ storage of the samples under vacuum at 4 °C, the measurements of oxidative stress biomarkers were repeated, and colour, water-holding capacity, sarcomere length (SL), and shear force (SF) were quantified. Significant correlations were found between LLBI parameters and pH 24 h post-mortem (pH_24h), colour coordinates, cooking losses (CL), drip losses (DL), and SF. Moreover, oxidative stress biomarkers also correlated with laser scattering parameters. Overall, LLBI demonstrated considerable potential as a rapid and non-invasive technique for assessing physicochemical quality attributes and oxidative stress-related traits in Arouquesa beef, supporting its application as an innovative tool for meat quality monitoring. Full article

As global photovoltaic (PV) installation capacity grows rapidly, the environmental pollution and resource waste from the large-scale end-of-life (EOL) wave have drawn increasing attention. Traditional disposal methods such as landfilling and incineration are no longer viable, making green recycling a logical path for the PV industry. This paper reviews recent progress in the disassembly and recycling of EOL crystalline silicon (c-Si) PV modules. It first describes the structural material composition of c-Si PV modules and summarizes global recycling policies and regulatory frameworks. It then analyzes the mechanisms and process parameters of major delamination technologies, including mechanical crushing, pyrolysis, thermal cutting, high-voltage pulse fragmentation, solvent-based approaches, and laser peeling. Methods for purifying silicon and recovering precious metals such as silver and copper are also covered. Finally, key challenges in the recycling field and future development trends are discussed, with the aim of supporting the advancement of c-Si PV recycling technologies and the sustainable development of related industrial chains. Full article

Historic urban landscapes are at continuous risk of loss due to urban modernization and the demolition of built heritage. Scan-based documentation methods such as laser scanning and photogrammetry become inapplicable, leaving demolished sites undocumented and unrecoverable through existing digital heritage workflows. This study develops a documentary-based Urban Digital Twin (UDT) framework for reconstructing demolished historic urban landscapes through the integration of historical documentation, geospatial analysis, and parametric modeling within the Historic Urban Landscape (HUL) approach. As a feasibility study, the framework reconstructs Chahar-Bagh Bala Street in Isfahan, Iran, a four-century-old promenade among the oldest urban streets in the Middle East, whose royal garden entrances, towers, water features, and promenade have been almost entirely replaced by industrial and modern structures. The methodology applies a nine-step workflow, integrating georeferencing, viewpoint reconstruction, cross-source validation, and HBIM parametric modeling, using historical maps, travel account engravings, archival photographs, and measured plans. The reconstruction confirms the historical existence and spatial locations, established through convergent visual evidence, of two lost royal garden entrances. The study further quantifies long-term historic green infrastructure loss, finding that approximately 70% of the original garden cover has been replaced. This replicable framework supports evidence-based heritage governance and sustainable urban regeneration, including the reintegration of historic green infrastructure into contemporary urban planning, particularly for rapidly transforming cities of the Global South. Full article

Background: Hepatocellular carcinoma (HCC) remains challenging to treat because of the limited therapeutic efficacy and insufficient selectivity of conventional therapies. To overcome these limitations, multifunctional nanoplatforms integrating biomimetic strategies and combination therapy have attracted increasing attention. Single-modality therapies are often limited by insufficient therapeutic efficacy and restricted mechanisms of action, highlighting the need for biomimetic nanoplatforms that integrate combination therapeutic strategies for enhanced antitumor performance. Methods: Herein, a biomimetic strategy-based nanoplatform (DI-ZM) was constructed via a combination of ZIF-8 biomineralization, physical adsorption of dihydroartemisinin (DHA) and indocyanine green (ICG), followed by HepG2 cell membrane coating to achieve homologous interaction. This design enables integrated chemotherapy, photothermal therapy (PTT), and photodynamic therapy (PDT) within a single system. Results: The resulting DI-ZM nanoparticles exhibited a hydrodynamic diameter of approximately ~200 nm with good colloidal stability and high drug-loading capacity. Under 808 nm laser irradiation, DI-ZM achieved a temperature elevation to ~66 °C within 5 min, together with efficient ROS generation. Compared with uncoated nanoparticles, the biomimetic membrane coating significantly enhanced cellular uptake and homologous targeting ability, as confirmed by CLSM and flow cytometry analysis. Benefiting from the biomimetic membrane coating, DI-ZM further exhibited improved homologous targeting and cellular uptake, which contributed to enhanced intracellular ROS generation. This was accompanied by significant mitochondrial membrane depolarization and apoptosis rates exceeding 80% in HepG2 cells under laser irradiation, ultimately resulting in markedly enhanced cytotoxicity. In addition, the biomimetic membrane coating also enabled efficient penetration of DI-ZM into multicellular tumor spheroids, indicating its improved tumor-penetration capability. In vivo antitumor studies further revealed effective tumor suppression with a tumor inhibition rate of approximately 97%, along with acceptable systemic tolerance in HepG2 tumor-bearing mice. Conclusion: The biomimetic membrane-coated ZIF-8 nanoplatform integrating chemotherapy with ICG-mediated phototherapy (photothermal and photodynamic therapy) provides an effective strategy for the combination therapy against HCC. Full article

A high-efficiency extra-cavity Raman generator is demonstrated using a potassium yttrium tungstate (KYW) crystal for the first time, achieving switchable yellow-green laser output at 556 nm and 560 nm. The KYW Raman crystal is single-pass pumped by 532 nm green light, which is obtained by the second-harmonic generation of a 1064 nm flash-lamp-pumped Nd:YAG electro-optic (EO) Q-switched laser. When the incident pump energy at 1064 nm is 156 mJ under a repetition rate of 1 Hz, the maximum output energy reaches 51.3 mJ at 532 nm with a slope efficiency of 41.5%. By adjusting the polarization direction of the 532 nm light, two characteristic Raman shifts of the KYW crystal can be selectively excited at 765 cm⁻¹ and 905 cm⁻¹. Furthermore, the 556 nm and 560 nm visible lasers are generated with the maximum output energies of 11.6 mJ and 16.2 mJ, corresponding to the slope efficiencies of 37.6% and 48.2%, respectively. Compared with the 532 nm pulse width (18.2 ns), an obvious Raman pulse width compression effect occurred (8.2 ns). Full article

The complexity and heterogeneity of tumors make monotherapy inadequate for effective tumor elimination, highlighting the urgent need for multifunctional synergistic therapeutic strategies. In this study, a near-infrared (NIR)-responsive multimodal therapeutic nanoplatform (FSINPs) was constructed by simple adsorption of indocyanine green (ICG) and Fe³⁺ onto silk fibroin nanoparticles. Molecular docking showed that ICG binds stably to silk fibroin mainly via hydrogen bonds. Density functional theory (DFT) calculations predicted that Fe³⁺ strongly coordinates with the sulfonate groups of ICG and quenches ICG fluorescence via intermolecular charge transfer. Under conditions mimicking the acidic and high-glutathione tumor microenvironment, the ICG-Fe³⁺ coordination is disrupted, leading to fluorescence recovery of FSINPs. Fe³⁺ catalyzes the Fenton reaction to generate hydroxyl radicals (·OH), thereby achieving chemodynamic therapy (CDT). Upon 808 nm laser irradiation, ICG acts as a dual photosensitizer capable of both photothermal therapy (PTT) and photodynamic therapy (PDT), generating local hyperthermia with a photothermal conversion efficiency as high as 48.7% and producing singlet oxygen (¹O₂). The photothermal effect facilitates ·OH production, and CDT enhances photodynamic efficacy. The synergistic action of the three therapeutic modalities results in potent light-activated cytotoxicity toward tumor cells. In vivo experiments demonstrated that FSINPs enable tumor microenvironment-responsive fluorescence imaging for over 48 h and achieve complete tumor eradication in a 4T1 tumor model without obvious systemic toxicity. This study provides a new strategy for constructing activatable imaging and highly synergistic PTT/CDT/PDT-integrated silk fibroin-based nanomedicines and offers computational chemistry references for their rational design and development. Full article

Pipe welding automation requires accurate weld seam extraction and reliable robotic weld path generation under complex geometric conditions. Existing vision-based approaches often rely on expensive laser sensing systems, multi-view sensing, or continuous seam tracking, resulting in increased hardware cost and system complexity. To address these limitations, this study proposes a deep learning-based offline robotic welding framework that generates a three-dimensional welding path from a single top-view Red–Green–Blue and Depth (RGB-D) image acquired prior to welding. The proposed framework integrates weld seam detection, semantic segmentation, morphology-based post-processing, RGB-D image alignment, coordinate transformation, and polynomial-based trajectory refinement into a unified pipeline for robotic weld path generation. A custom pipe welding dataset consisting of 1476 annotated images collected from representative industrial pipe materials with varying diameters was constructed to evaluate the proposed framework. The experimental results demonstrate that the proposed Region of Interest (ROI)-guided weld seam extraction pipeline improves the U-Net segmentation performance from 0.735 to 0.791 mean Intersection over Union (mIoU), while the detection model achieves a Recall of 0.988 and an mean Average Precision at an Intersection over Union threshold of 0.5 (${\mathrm{mAP}}_{50}$) of 0.995. Furthermore, polynomial-based trajectory refinement reduces the three-dimensional positional root mean square error (RMSE) to 0.333 mm, enabling continuous robotic welding over the entire visible weld seam without additional path modification. These results demonstrate that the proposed framework provides a practical and cost-effective solution for offline robotic weld seam extraction and weld path generation, while establishing a promising foundation for future extension toward online robotic welding through real-time weld seam tracking and adaptive trajectory correction. Full article

Tribology is a growing field concerning reductions in the environmental footprint of tribological systems while increasing their operational efficiency by minimizing friction, wear and lubrication in an environmentally conscious manner. This review aims to discuss in detail sustainable lubrication strategies, with particular emphasis on surface modification and coating-based strategies for advanced tribological applications. The surface engineering techniques covered in this study are critically reviewed with regard to their ability to improve wear resistance, reduce friction and increase the durability of components, such as laser surface texturing (LST), nitriding, plasma treatment and advanced coating technologies such as DLC-, TiN-, CrN- and PVD-based coatings. Another key focus is on the synergy of sustainable lubricants and engineered surface coatings. The tribochemical compatibility of eco-friendly lubricants, bio-lubricants, ionic liquids and advanced coated surfaces is explained in detail, because they are essential for the formation of stable tribofilms, lubricant retention, reductions in surface degradation, and the minimization of tribological losses. They are an important component of environmental footprint, energy consumption and the thermal stability and service life of tribological components. Recent developments in coating-assisted green tribology, sustainable tribochemistry and circular sustainability concepts of the design of tribological systems are also included in the review. In addition, the review briefly outlines the use of Life Cycle Assessment (LCA) as a potential tool for the future evaluation of the environmental sustainability of tribological systems. The proposed expanded set of Green Tribology principles offers useful guidance for the implementation of tribology-based solutions toward more sustainable engineering systems and responsible resource utilization. Full article

Despite rapid advances in laser display technology, existing evaluation frameworks remain confined to isolated physical metrics, decoupled from human visual perception. This study presents the laser display comprehensive testing system (LD-CTS003), a unified platform integrating physical characterization and visual perceptual assessment. Grounded in opponent-process theory, the system implements a complete color conversion pipeline from display RGB through CIE XYZ and LMS to the Derrington–Krauskopf–Lennie space, linking spectral output to retinal cone responses. The hardware architecture features five-axis precision motion and multi-sensor synchronous acquisition, while the software supports both conventional optical measurements and psychophysical experiments. Static image resolution was evaluated via stripe-pattern modulation analysis across viewing distances, and visual contrast sensitivity was measured using Gabor stimuli under varying luminance and eccentricity. The results demonstrate that reduced viewing distances enhance effective resolution, with text display imposing stricter requirements than image display. Contrast sensitivity functions exhibit band-pass profiles, with luminance and eccentricity strongly modulating achromatic and red–green channels, whereas yellow–violet responses remain relatively robust peripherally. By unifying objective metrology and subjective evaluation, this work establishes a perception-oriented framework for laser display quality assessment, providing a physiologically grounded foundation for display optimization and standard development. Full article

This study investigated the effect of magnetic coupling of Fe³⁺ on Ho³⁺ luminescence in the double perovskite Cs₂NaScCl₆. Under 980 nm laser excitation, red emission from Ho³⁺ ions was observed in Cs₂NaScCl₆:Ho³⁺/Fe³⁺ samples. We propose that this arises from spin-selective up-conversion mediated by magnetic polarons (EMPs). However, green emission from the ⁵F₄/⁵S₂ levels was not observed in this system. The experimental results suggest that localized EMPs form via ferromagnetic short-range ordering between Fe³⁺ and Ho³⁺ or among Fe³⁺ ions. These EMPs can be directly excited to higher energy levels via a biexciton absorption transition, then relaxed to the ⁵F₅ level of Ho³⁺ through ferromagnetic coupling. Under X-ray excitation, the characteristic emission peaks of Ho³⁺ in Cs₂NaScCl₆:Ho³⁺/Fe³⁺ become smoother, lose fine structure, and significantly decrease in intensity with increasing Fe³⁺ concentration. Based on this, we prepared Fe³⁺-free Cs₂NaScCl₆:Ho³⁺ and explored its excellent scintillation performance, with a detection limit as low as 37.73 nGy_air s⁻¹, below the medical diagnostic dose, surpassing the performance of commercial scintillators such as LuAG:Ce and BGO. This work reports the phenomenon of using Fe³⁺ as a sensitizer to achieve up-conversion sensitization in chloride double perovskites and demonstrates the application potential of Fe-free systems in ultra-low-dose X-ray imaging. Full article

Modern optoelectronic devices, such as light-emitting diodes (LEDs) and laser diodes, rely on nitride-based (GaN, AlN, and InN) quantum structures, which underpin current technologies. These systems enable emission across a broad spectral range from ultraviolet to infrared with properties tunable via composition, strain, and quantum confinement. This review summarizes progress in the performance of nitride emitters across the full spectral range, with particular emphasis on the evolution of external quantum efficiency (EQE). Nitride emitters are primarily based on InGaN quantum wells, while AlGaN quantum wells are used for ultraviolet operation. Device performance is governed by the intrinsic properties of these structures, which also determine key physical challenges across different wavelength regions. Blue InGaN LEDs achieve the highest efficiencies (~60–80% EQE), while green devices are limited to ~20–35% due to the “green gap,” with further reduction (~5–20%) toward longer wavelengths. In the ultraviolet, AlGaN-based emitters exhibit lower performance due to material and structural challenges, although steady progress is being made. Special attention is given to mechanisms limiting EQE, including efficiency droop in the green–red region, and ongoing efforts to mitigate these effects. Finally, perspectives for future applications of [ are outlined. Full article

Background/Objectives: Acorus tatarinowii Schott volatile oil (ATVO), a bioactive component of traditional Chinese medicine, is susceptible to light-induced oxidation and compositional changes. This study aimed to develop a chitosan-modified Saigae Tataricae Cornu particle (MSTC)-stabilized Pickering emulsion (PE) to improve the light-oxidative stability and in vivo disposition of ATVO. Methods: Saigae Tataricae Cornu particles were modified with chitosan and used to prepare an oil-in-water PE encapsulating ATVO. Particle wettability, morphology, structural interactions, emulsion type, interfacial distribution, droplet size, and zeta potential were characterized. The light-oxidative stability of ATVO was evaluated under light using peroxide value, malondialdehyde content, and gas chromatography-mass spectrometry (GC-MS) analysis. The pharmacokinetic behavior of α-asarone and β-asarone was further investigated in rats. Results: Chitosan modification increased the contact angle of Saigae Tataricae Cornu particles from 65.37° to 83.23°, indicating improved wettability and interfacial affinity. The resulting PE showed good physical stability, with a droplet size of 2.51 μm and a zeta potential of +32.00 mV. Confocal laser scanning microscopy (CLSM) confirmed that MSTC particles adsorbed at the oil–water interface and encapsulated ATVO within the oil droplets. Compared with free ATVO and the physical mixture, the PE reduced peroxide and malondialdehyde formation, slowed light-induced changes in volatile components, and better preserved major bioactive constituents. Pharmacokinetic analysis showed that the plasma concentration-time curve from 0 to t (AUC_0–t) and maximum plasma concentration (C_max) of α-asarone increased by 2.02- and 2.47-fold, respectively, whereas the effect on β-asarone was relatively limited. Conclusions: MSTC-stabilized PE provides an effective interfacial-barrier strategy for protecting ATVO against light-oxidative deterioration. This study highlights the potential of modified natural medicinal particles as green stabilizers for improving the stability, quality consistency, and delivery performance of volatile-oil-containing traditional Chinese medicine preparations. Full article

Hollow mesoporous silica nanoparticles (HSNs) were synthesized via the Stöber method using resorcinol–formaldehyde resin as a template and further developed as a multifunctional nanocarrier for synergistic chemo–photothermal therapy. Docetaxel (DTX) and indocyanine green (ICG) were co-loaded into HSNs as the prodrug and photothermal agent. The loading sequence of these agents can critically affect encapsulation efficiency. Preloading DTX followed by ICG incorporation achieved the highest drug loading (38.65%) and preserved the photoactivity of ICG. The resulting ICG&DTX@NH₂-HSNs exhibited strong and stable near-infrared photothermal conversion, as well as pH- and laser-responsive drug release behavior. In vitro studies confirmed efficient cellular uptake by 4T1 tumor cells and enhanced cytotoxicity compared with single treatments. In vivo experiments demonstrated significant tumor growth suppression in 4T1 tumor-bearing mice, with the greatest effect observed under combined ICG&DTX@NH₂-HSNs and laser irradiation. Importantly, histological analysis of major organs revealed no obvious toxicity, confirming the biosafety of the present nanoplatform. This study confirmed the potential of hollow mesoporous silica-based nanocarriers as safe and effective platforms for combined chemotherapy and photothermal cancer therapy. Full article