Search Results (761)

The production technology and provenance of 22 beads from the Dvāravatī-period site of Khok Phithak at Khu Bua, central Thailand (6th–11th centuries CE), was investigated using a multi-analytical approach combining VP-SEM-EDS, LA-ICP-MS, and micro-Raman spectroscopy. Macroscopic and microstructural evidence indicates that most of the glass beads were manufactured by the drawn-tube method, consistent with the supply of imported Indo-Pacific beads rather than local primary glass production at Khu Bua. However, the assemblage is not technologically homogeneous. From a compositional point of view, 19 beads belong to the m-Na-Al-1 subgroup, linking them to South Asian glassmaking traditions and the large-scale Indo-Pacific bead industry. One bead corresponds to plant-ash soda–lime glass, indicating an additional supply stream, while two outliers, a slag-derived ferruginous glass bead and a chalcedony/agate bead, demonstrate that bead circulation at Khu Bua also involved materials of distinct technological and geological origin. Coloring and opacification technologies, including Pb-Sn opacifiers in green and yellow-green beads and copper-based striking in orange beads, further indicate the use of technologically controlled recipes beyond simple bulk glass import. These results support the interpretation of Khu Bua as an inland consumer center embedded within long-distance Indian Ocean exchange networks. Full article

A rare carved lacquer (tixi) plate recovered from the Southern Song Dynasty Nanhai No. 1 shipwreck was examined to reconstruct its coating stratigraphy, raw materials, and manufacturing sequence. Detached fragments collected before conservation treatment were investigated by cross-sectional optical microscopy, micro-Raman spectroscopy, thermally assisted hydrolysis–methylation pyrolysis–gas chromatography/mass spectrometry (THM-Py-GC/MS), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), and wood-anatomical microscopy. The polished cross-section contains nine lacquer layers with a combined thickness of 387.3 μm above a heterogeneous ground, yielding ten visually distinguishable strata. Alternating dark, red, and yellow layers establish the technological basis for the carved polychrome effect. Raman bands identify cinnabar (HgS) in the red layer and orpiment (As₂S₃) in the yellow layer. THM-Py-GC/MS detected homologous alkenes, alkanes, and alkylbenzenes diagnostic of Chinese lacquer derived from Toxicodendron vernicifluum. Monocarboxylic acids were present, whereas no clear dicarboxylic-acid markers of a drying oil were observed; because the object was waterlogged and degraded, this absence is treated as a lack of positive evidence rather than proof that oil was never used. The ground is enriched in Ca and P and is therefore consistent with a bone-ash-based filler, although phase-specific confirmation remains necessary. Wood anatomy identifies the substrate as Chinese fir (Cunninghamia lanceolata, Cupressaceae). Together, the results document an organic–inorganic multilayer coating system and provide material evidence for Southern Song carved-lacquer technology, while defining conservation risks associated with a waterlogged wooden core and light-sensitive pigments. The marine archaeological context and the support-to-surface, layer-resolved design distinguish this case from most previous studies of Song-dynasty lacquerware. Beyond technological reconstruction, the findings identify conservation priorities for waterlogged wood, the wood–ground–lacquer interface, and light-sensitive pigmented layers, and provide a transferable evidence framework for comparative research on archaeological lacquer. Full article

Although traditional carbon-based supercapacitor electrode materials exhibit good cycling stability and conductivity, their specific capacitance and energy density are limited by the dual-layer capacitor storage mechanism, making it difficult to satisfy the growing demand for high-performance energy storage. Consequently, the introduction of pseudocapacitive materials with Faradaic charge transfer characteristics has become a research focus in the field of supercapacitors. Herein, Cu/Co metal-anchored carbon composites (IL-Cu@NC and IL-Co@NC) have been successfully synthesized using metal-functionalized ionic liquids as both precursors and dopants via a one-step carbonization process. The micro-morphology, crystallinity, surface chemical states, and pore structure of the prepared electrode materials have been systematically characterized using scanning electron microscopy (SEM), chronoamperometry, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and N₂ adsorption–desorption measurements. The energy storage performance of the fabricated electrode materials has been investigated using a three-electrode system in an alkaline solution. The optimized IL-Cu@NC electrode achieves a specific capacitance of 653 F g⁻¹ at 0.5 A g⁻¹, along with stable cycling performance. This research proposed a feasible strategy for developing high-performance supercapacitor electrodes by functionalizing metals with ionic liquids, achieving enhanced specific capacitance compared with conventional carbon materials. Full article

The corrosion of tin amalgam reflective coatings on Qing Dynasty reverse glass paintings has traditionally been attributed to oxidation pathways. No other corrosion types have been reported for this artifact class to date. This study investigated two reverse glass paintings using Scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS) and micro-Raman spectroscopy (Raman). In one sample, the corrosion products are romarchite (SnO), tin tetroxide (Sn₃O₄), and cassiterite (SnO₂), confirming the conventional oxidation pathway. In the other sample, abhurite (Sn₂₁Cl₁₆(OH)₁₄O₆) and hydroromarchite (Sn₃O₂(OH)₂) are identified alongside tin oxides. This is the first report of chlorine-bearing corrosion products in Qing Dynasty reverse glass paintings. This finding indicates that the coating was exposed to a high-humidity, chloride-containing environment. The coexistence of chloride-mediated and oxidation-pathway products reflects microenvironmental heterogeneity on the coating surface. Preventive conservation for similar objects should prioritize maintaining a stable relative humidity at approximately 50%, excluding exogenous chloride sources, and avoiding acidic pollutants. Full article

Flexible electronic textiles hold potential applications across various fields, yet current functionalization methods frequently suffer from poor coating uniformity and severe aesthetic alteration. This study addresses these challenges by establishing a multi-analytical approach, based on Raman spectroscopy together with DLS, Zeta potential and XPS measurements, to optimize graphene oxide (GO) precursor selection prior to electrostatic deposition onto cotton fabrics using a polyethyleneimine linker. This coating strategy was inspired by layer-by-layer deposition technique and centrifugation was used to partition a heterogeneous commercial GO precursor into three distinct homogeneous fractions. Raman spectroscopy revealed that centrifugation acts not merely separating GO based on its size but effectively sorts GO sheets based on their chemical functionalization degree. Consequently, this approach allows for the identification of the optimal precursor fraction, balancing sheet dimensions with defect density, to ensure strong functionalization. Overall, this work established a foundational spectroscopic methodology for precursor selection, deposition monitoring and process optimization, which can also be extended to the characterizing and comparison of different commercial GO batches from different industrial suppliers. Finally, micro-Raman mapping and XPS were preliminary applied to verify the textile fiber functionalization. Full article

Nanoplastics and microplastics have become an increasing ecological and health concern due to their widespread presence in the environment and food chain. In this study, Caco-2 cells were used as an in vitro model of the human intestinal epithelium to investigate the cytotoxic effects of polystyrene nanoparticles and microparticles of varying sizes, concentrations, and surface modification. Oxidative stress and apoptosis were evaluated following particle exposure. Raman spectroscopy, combined with machine learning analysis, was employed to detect and characterize biochemical alterations in the cells. Several peak ratios were selected to cluster data depending on size. A correlation between apoptosis and both concentration and Raman score was established highlighting its potential as a non-invasive tool to monitor nanoparticle-induced cellular damage. Resveratrol pretreatment reduced some of these harmful effects of amine-modified nanoplastics, reducing reactive oxygen species generation. This study demonstrates the potential of combining Raman spectroscopy and machine learning to assess the cytotoxic effects of micro- and nanoplastics and identifies protective strategies such as antioxidant pretreatment. Full article

Background: Human respiratory exposure to microplastics (MPs) has recently been demonstrated, but their distribution within thoracic tissues and association with lung malignancy remain poorly characterised. We investigated the presence, burden, morphology, and spectroscopic characteristics of MPs in thoracic tissue specimens and their relationship with lung malignancy. Methods: In this prospective observational study, 50 adults undergoing diagnostic thoracic surgical procedures for suspected lung malignancy were enrolled. Lung, pleural, and mediastinal lymph node specimens underwent contamination-controlled processing, microscopy, and representative particle analysis by confocal micro-Raman spectroscopy. Associations between MPs and clinicopathological variables were analysed. Results: Sixty-two morphologically identified microplastic particles were detected in 50 specimens, with MPs detected in 32 patients (64%). Fragments accounted for 97% of particles, with a median burden of one particle per specimen (IQR, 2). MP detection was significantly more frequent in patients with primary lung malignancy than in patients without primary lung malignancy, including those with metastatic malignancy and benign disease (81.8% vs. 50.0%, p = 0.020), who also exhibited a higher tissue MP burden (p = 0.024). Primary lung malignancy remained independently associated with MP detection after adjustment for age and smoking exposure (OR 4.09, 95% CI 1.06–15.79; p = 0.041). Particle morphology varied by biopsy site, with significantly smaller particles identified in mediastinal lymph nodes (p = 0.006). Synthetic anthropogenic spectral signatures were identified in 71% of particles. Conclusions: MPs are frequently present in human thoracic tissues and are associated with primary lung malignancy. Compartment-specific particle characteristics suggest distinct patterns of respiratory MP deposition and retention, supporting multicentre mechanistic studies. Full article

This study investigates the atmospheric corrosion behavior of high-lead bronze alloys within a simulated aggressive environment characterized by high humidity, acidity, chlorides, oxygen, and CO₂. The evolution of surface morphology and corrosion products was systematically monitored using colorimetric analysis and micro-Raman spectroscopy. Results indicate that the initial patina primarily comprised cuprite (Cu₂O) and cassiterite (SnO₂), which are predominantly benign phases. During the early corrosion stage, lead oxidation and carbonation prevailed, generating abundant bright-white cerussite. Subsequently, as copper-driven corrosion became dominant, these white deposits diminished and were progressively replaced by characteristic green “bronze disease”, identified as atacamite (Cu₂(OH)₃Cl). The findings reveal that preferential lead corrosion is likely to induce localized pitting, thereby accelerating degradation of the copper substrate. Consequently, higher lead content may reduce the overall corrosion resistance of bronze artifacts under these specific conditions. These results offer experimental insights into atmospheric corrosion mechanisms and inform the development of evidence-based conservation strategies for bronze cultural heritage. Full article

Structural colors, generated by the physical interaction of light with micro- and nanostructured architectures, have emerged as an important platform in nanophotonics owing to their high color saturation, exceptional photostability, and long-term color durability. This review provides a comprehensive overview of recent advances in structural colors and establishes a unified classification framework based on their macroscopic angular optical responses. The intrinsic angular characteristics of four fundamental color-generation mechanisms are first distinguished, providing the physical basis for classifying structural colors into iridescent and non-iridescent systems. Representative iridescent architectures, including thin films, one-dimensional (1D) to three-dimensional (3D) photonic crystals, and diffraction gratings, are systematically reviewed, together with non-iridescent strategies based on independent plasmonic and dielectric resonators, quasi-amorphous structures, and engineered metasurfaces. Strategies for enhancing structural color visibility and saturation through absorption management are further discussed, particularly for suppressing undesired broadband and multiple-scattering backgrounds. Additionally, this review systematically summarizes quantitative methodologies for evaluating structural colors, including spectral metrics, CIE 1931 and CIE1976 color spaces, CIEDE2000 color difference, quantitative angular-response metrics, spatial resolution and pixel limits, and structural-order characterization using orientation parameters and two-dimensional fast Fourier transform (2D FFT) analysis. Particular attention is given to the quantitative assessment of angular stability through wavelength shifts and perceptual color differences, while recognizing that a universally accepted numerical boundary between iridescent and non-iridescent coloration has not yet been established. Representative functional applications are also reviewed, including self-cleaning coatings, passive daytime radiative cooling, label-free chemical and gas sensing, reflectometric interference spectroscopy (RIfS), surface-enhanced Raman scattering (SERS), and anti-counterfeiting. By integrating color-generation mechanisms, angular optical responses, quantitative evaluation methods, and functional applications, this review provides a unified framework for objectively comparing structural color platforms and highlights key trade-offs among color quality, angular stability, structural precision, durability, scalability, and multifunctionality, thereby providing design guidance for next-generation optical materials and devices. Full article

Micro- and nanoplastics (MNPs) are increasingly recognized as emerging contaminants in drinking water, yet quantitative data remain limited due to analytical challenges. In this study, the occurrence, morphology, and polymer composition of MNPs were investigated in commercial drinking water from Saxony-Anhalt, Germany, including ultrapure water, tap water, and five bottled mineral waters. A dual-stage cascade filtration system combining silicon filters (5 µm pore size) and aluminum oxide membranes (90 nm pore size) was employed for size-selective particle separation. Retained particles were characterized using optical microscopy, scanning electron microscopy (SEM), and Raman spectroscopy. Tap water exhibited the highest concentration of microparticles, whereas ultrapure water showed minimal microparticle contamination. Nanoparticles were detected in all samples, including ultrapure water, with mean particle sizes below 1 µm, highlighting the pervasive nature of nanoscale plastic contamination. Raman analysis identified polyethylene terephthalate (PET) as the most frequently detected synthetic polymer, together with polypropylene (PP), polystyrene (PS), and poly(methyl methacrylate) (PMMA). The results demonstrate that no drinking water source tested in this study was free of detectable MNPs and underline the need for standardized analytical approaches capable of reliably detecting MNPs in drinking water. Full article

Carbonate jade has emerged as a recently recognized commercial variety in the Chinese gemstone market. Systematic gemological and mineralogical investigations on carbonate jade, however, remain very scarce. Three Xinjiang calcite-dominated jade samples were investigated by using Fourier-transform infrared (FTIR) spectroscopy, Raman spectroscopy, ultraviolet-visible (UV-Vis) absorption spectroscopy, microbeam X-ray fluorescence (Micro-XRF) spectrometry, trace element analysis, in situ U-Pb dating, and C-O isotope analysis. The orange-red color originates from staining by hematite and magnetite inclusions, while the green color is produced by d-d electronic transitions of lattice-bound Fe³⁺ and Mn²⁺. The provenance comparison reveals systematic differences in trace element compositions between the Xinjiang carbonate jade and Pakistani Lvwen stone: the Xinjiang samples are characterized by extremely low Cu and Sr contents, whereas the Pakistani Lvwen stone has high Cu, Mn and Sr contents, and low Fe content. The U-Pb age obtained for the Xinjiang carbonate jade sample coincides with a Late Cretaceous rapid cooling event. Enriched light rare earth element (LREE) and C-O isotope (δ¹³C_V-PDB = −1.19–2.21‰, δ¹⁸O_V-SMOW = 15.00–20.01‰) signatures indicate that the carbonate-precipitating fluids were derived from marine carbonate wall rocks. These findings provide new mineralogical and geochemical constraints on the coloration mechanism, provenance, and fluid evolution of carbonate jade from Xinjiang. Full article

Three commercial red–white banded rhodochrosite samples sold as Argentine “Rosa del Inca” material were investigated using conventional gemological observation, mineralogical analysis, micro-area chemical analysis, and spectroscopy. The red and white bands differ in color, transparency, and microstructure. However, both bands are mainly rhodochrosite. No evidence indicates that calcite, dolomite, or other Ca-bearing carbonate minerals are the main phases in the white bands. Representative EPMA analyses of LMK-02 show that the analyzed white-band points tend to contain slightly lower Mn and relatively higher Fe and Mg than the red-band points, while CaO is below the detection limit at all representative EPMA positions. Micro-XRF mapping of LMK-02 reveals only local and discontinuous enrichments of Ca and Zn; however, the mineralogical identity and occurrence mode of these enriched domains remain unresolved. Combined with the EPMA data, the XRD, FTIR, Raman, and UV–Vis results do not support marked Ca enrichment, extensive Ca substitution for Mn, or abundant Ca-bearing carbonate phases in the analyzed white bands of LMK-02. Instead, the results indicate Ca-poor compositional variation within rhodochrosite, with the representative EPMA data showing a descriptive tendency toward slightly lower MnO and relatively higher FeO and MgO contents in the analyzed white-band points. 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

Understanding the processes behind Earth’s CO₂ degassing is crucial for clarifying how carbon is cycled by geologic processes on our planet. Earth’s carbon degassing results from magmatic and metamorphic processes controlled by large-scale plate tectonics. However, the nature and amount of diffuse CO₂ fluxes from faults in continental rifts remain largely unconstrained. Recent research reports important CO₂ fluxes from deep faults over 17 × 10⁴ km² in the East African Rift System (EARS), highlighting the need for a more detailed inventory of diffuse soil emissions. Across such extensive regions, only satellite observations can provide the broad measurement range needed to meet the observational requirements for long-term, large-scale overlay datasets. While space-based data provide extended coverage for large-scale identification of CO₂ emission sources, to date, only the column-averaged total CO₂ atmospheric content has been measured from space. Range-resolved measurements of CO₂ concentration with the vertical accuracy needed to detect diffuse soil emissions are not available from space, preventing direct quantification of Earth degassing over large regions. In this paper, we focus on a new approach to measuring soil CO₂ fluxes by a statistical deconvolution of column measurements of global atmospheric CO₂ content. Anthropogenic increase, seasonal climatology at a small regional scale, and soil fluxes are measured without the use of ancillary measurements or model simulations. We combine petrology of fluid and melt phases in mantle rocks with a new satellite data analysis to reveal, for the first time, large CO₂ fluxes from the lithospheric mantle to the atmosphere in a much wider region than previously considered (22.4 × 10⁵ km²), including the Ethiopian and East African domes, where magmatism is no longer active or absent. We infer that diffuse soil emissions are measurable from space, and that Earth’s tectonic carbon fluxes are considerably more relevant than currently considered, with a crucial impact on the balance of the global carbon cycle. Full article

Airborne microplastics (AMPs) are recognized as emerging pollutants, exerting widespread impacts on both the ecological environment and human health. While existing research has predominantly focused on the occurrence characteristics, studies addressing human exposure patterns remain limited. In this study, a typical campus in Zhenjiang, a city in East China, was selected as the research site. By integrating students’ daily activity trajectories, active sampling methods were employed to estimate 24 h inhaled AMP intake, alongside simultaneous monitoring of environmental parameters such as temperature, relative humidity, and air pressure. Each participant used one filter throughout the 24 h monitoring period. The results revealed average AMPs abundances of 0.49 items/m³ and 0.82 items/m³ during the sampling period, with fibers being the most prevalent morphology (63%), followed by fragments (27%) and pellets (10%). μ-Raman spectroscopy analysis identified polypropylene (PP), polystyrene (PS), and polymethyl methacrylate (PMMA) as the primary polymer types, constituting 70% of the total. PP and PS were the dominant polymer types in the two trajectory-integrated samples; however, polymer identity alone did not permit definitive source attribution. A large proportion of the μ-Raman-identified particles fell within the 1–5 μm range; however, this fine-size fraction should be interpreted cautiously because representative spectra and particle-specific spectral matching records were not available for further verification. Based on the activity trajectories, the estimated daily inhalation intake of AMPs by students in campus micro-environments was approximately 91.5 items/day per person. PMMA was identified in Sample A, whose trajectory included the volleyball gym; however, the integrated sampling design did not permit location-specific source attribution or comparison of individual activity locations. This study provides preliminary information on AMP occurrence characteristics and estimated inhaled intake. This study is a preliminary pilot study, with 24 h personal exposure monitoring conducted on only two participants. We will increase the sample size in follow-up experiments to draw broader conclusions regarding airborne microplastic exposure across the campus. Full article