Search Results (727)

LaFeO₃ nanofibers and Ag-doped LaFeO₃ nanofibers were fabricated via an approach combining electrospinning with calcination. Their crystal structures, micro-morphologies, and chemical compositions were determined by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, and Fourier-transform infrared spectroscopy. In addition, the conduction mechanisms and magnetic properties of the two samples were investigated using a semiconductor analyzer and a vibrating sample magnetometer. Rietveld refined X-ray diffraction analyses confirmed the orthorhombic structure. The two samples showed a nanofibrous structure. For Ag-doped LaFeO₃, the conduction was dominated by the ohmic conduction mechanism in a low-resistance state, while it was governed by space-charge-limited current conduction in a high-resistance state. It also showed a high on/off ratio of 3.6 × 10³. The coercivity and remanence values of Ag-doped LaFeO₃ were 200 Oe and 0.000404 emu g⁻¹. This, thus, indicates the considerable application potential of Ag-doped LaFeO₃ for resistive random-access memory devices and magnetoresistive random-access memory devices. Full article

Background/Objectives: Accurate determination of active pharmaceutical ingredient (API) particle size within dry powder inhaler (DPI) formulations is essential for ensuring effective pulmonary delivery but remains analytically challenging due to low API content and micronized particle size. Methods: In this study, scanning electron microscopy (SEM) coupled with energy-dispersive X-ray microanalysis (EDX) was used to directly identify and calculate the API particle size within several different commercial DPI products fit for purpose under regulatory constraints. The method exploits unique elemental markers inherent to each API, enabling reliable discrimination from excipients without prior sample modification or API extraction. Results: Large-area SEM–EDX mapping was used to localize API particles, followed by high-magnification imaging and confirmatory spot microanalysis. Particle sizes were manually measured for at least 50 API particles per formulation using image analysis software, and particle size distribution parameters were calculated from equivalent spherical diameters. Conclusions: The methodology was successfully applied to Spiriva^®, Anoro^® Ellipta, and Relvar^® Ellipta inhalation powders, revealing micronized APIs with distinct morphological features and verifying systematic application across products. Cross-validation against laser diffraction measurements of pure APIs demonstrated statistical equivalence, confirming the robustness and analytical utility of the proposed method for particle size assessment in DPI formulations. Full article

This study assesses indicative technical correspondences and divergences between Francisco de Zurbarán’s painting practices and those observed in the seventeenth-century Óbidos workshop (Baltazar Gomes Figueira and Josefa d’Óbidos). We focus on the composition and function of priming layers, the shadow-to-light painting sequence, and pigment/binder usage. A multi-analytical approach was employed: portable X-ray Fluorescence (XRF), Optical Microscopy on polished cross-sections (OM), Scanning Electron Microscopy in backscattered mode with Energy-Dispersive X-ray analysis (SEM-BSE/EDS), Micro-Confocal Raman Spectroscopy (µ-Raman), and Micro-Fourier Transform Infrared Spectroscopy (µ-FTIR). Rather than treating single pigments as diagnostic, we compare patterns of application and stratigraphic behaviour—notably a two-layer priming, in which a finer, Fe-rich upper layer is actively used to build shadows, and a consistent exploitation of the priming as a value layer in a shadow-to-light sequence. Materials largely overlap, while priming compositions differ, plausibly reflecting local resources. Given the small corpus (two works by Zurbarán, one by Baltazar, and one by Josefa), conclusions are presented as indicative and contextualized within Iberian workshop practice. Full article

The TaiLing Mausoleum in Western Qing Tombs has great aesthetic value and a rich history. In this study, we conducted an analysis of the materials used in the architectural polychrome paintings of the TaiLing Mausoleum. Optical microscopy (OM), portable X-ray fluorescence (p-XRF), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM–EDX), micro-Raman spectroscopy (μ-RS), and X-ray diffraction (XRD) were used to analyze the paintings of Long’en Gate in TaiLing Mausoleum. The results indicate that the main minerals in the ground layer are quartz, augite, feldspars and illite. The gilding materials employed gold leaf. The red pigment is hematite, and the black pigment is carbon black. The green pigment is emerald green with barium sulfate as an extender. The blue pigments are smalt and synthetic ultramarine. In some areas, emerald green is observed overlaying smalt, suggesting that the paintings at Long’en Gate underwent overlay restoration or repainting from the late Qing Dynasty to modern times. These results can support future conservation of the polychrome paintings at the TaiLing Mausoleum. Full article

Catalytic ozonation often suffers from a low ozone utilization rate and incomplete mineralization of organic pollutants. To address these challenges, we designed and prepared a novel catalyst via a one-step thermal polymerization method, anchoring single-atom manganese on a glucose-derived carbon network-modified C₃N₅ framework (Mn/C-C₃N₅). Aberration-corrected high-angle annular dark-field scanning transmission electron microscopy (AC-HAADF-STEM) on an FEI Titan Themis Z microscope confirmed the atomic dispersion of Mn sites, while Raman spectroscopy using a Renishaw inVia Reflex laser micro-Raman spectrometer verified the successful incorporation of a graphitic carbon network within the C₃N₅ matrix. Moreover, electrochemical analyses, including electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) performed on a Bio-Logic SP-150 electrochemical workstation, demonstrated that the integration of the conductive carbon matrix substantially enhanced the interfacial charge transfer capability. The optimized Mn/C-C₃N₅ catalyst demonstrated exceptional performance in phenol mineralization, achieving a 97% total organic carbon (TOC) removal within 60 min, a remarkable improvement compared to pristine C₃N₅ (30%). Furthermore, the catalyst exhibited excellent operational stability, preserving more than 95% of its original activity over five repeated runs. Mechanistic investigations, including electron paramagnetic resonance (EPR) spectroscopy and radical quenching experiments, revealed that the Mn/C-C₃N₅ system accelerated the generation of multiple oxidizing radicals (•O₂⁻, ¹O₂, and •OH), with •OH identified as the predominant reactive species responsible for complete mineralization. This work establishes an integrated catalytic platform and provides fundamental insights into electronic structure modulation for designing advanced oxidation catalysts. Full article

To investigate the influence of humus on the corrosion behavior of high-tin bronze in soil environments, potentiostatic polarization was applied to simulate early-stage corrosion under controlled conditions. Open-circuit potential and potentiodynamic polarization tests were performed, and corrosion products were characterized by stereo microscopy, SEM-EDS, and confocal Raman spectroscopy. A Cu–Sn–Pb ternary alloy was examined in simulated archaeological soil solutions with selective humus addition at different pH values. A bilayer structure, consisting of a secondary corrosion layer and a semi-corroded transition zone, developed in all media, with more extensive corrosion under weakly acidic conditions. In acidic environments, humus enhanced preferential α-phase corrosion, associated with copper depletion and tin enrichment as SnO₂. Under weakly alkaline conditions, humus mainly affected surface color and micro-morphology without altering the overall corrosion pattern. Electrochemical testing reproduced corrosion layer structures similar to those formed during early burials, but differences in morphology were observed. The results suggest that, as an accelerated corrosion technique, electrochemical methods can reproduce key features of early-stage corrosion in high-tin bronze and serve as an effective tool for monitoring corrosion behavior. Full article

Mitochondria play a crucial role in cellular bioenergetics, signaling, and metabolism; yet, many fundamental mechanisms such as the proton transfer along the membranes, the link between membrane curvature and oxidative phosphorylation, and the nanoscale organization of enzyme supercomplexes remain poorly understood due to the limitations of classical biochemical approaches. This review addresses this gap by systematically analyzing the contemporary physical methods used to investigate the mitochondrial structure and function from the micro to nano scale. It covers advanced fluorescence and super-resolution microscopy, electron and volume electron microscopy, and scanning probe techniques, as well as cryo-electron tomography for resolving supramolecular assemblies in near-native conditions. The review highlights the applications of the modern fluorescent probes, expansion and phase microscopy, and machine-learning-based image analysis for a quantitative assessment of the mitochondrial morphology, membrane potential, and dynamics in living cells and tissues. Complementary spectroscopic and scattering methods, including Raman spectroscopy, NMR, and X-ray and neutron scattering, are discussed as tools for probing the redox state, metabolite composition, and membrane organization. Emphasis is placed on integrating high-resolution experimental data with advanced computational frameworks to test competing models of mitochondrial function and pathology, and to guide the development of biomimetic and biomedical technologies. Full article

Polymeric electrolyte membranes based on a low equivalent-weight Aquivion^® commercial dispersion (D72-25BS; EW = 720 g eq⁻¹, Syensqo) were fabricated using a standardized in-house doctor-blade casting technique for application in proton exchange membrane fuel cells (PEMFCs). The low equivalent-weight (EW) Aquivion^® dispersion is a copolymer of tetrafluoroethylene (TFE) and sulfonyl fluoride vinyl ether (SFVE), commonly referred to as a short-side-chain (SSC) ionomer, which exhibits higher ion-exchange capacity (IEC) and proton conductivity than long-side-chain (LSC) perfluorosulfonic membranes. A home-made 30 wt.% Pt/CeO₂ radical scavenger (denoted syn-scavenger) was synthesized via a colloidal method and incorporated into the Aquivion^® membranes to investigate its mitigating effect on chemical degradation induced by peroxide radicals, a role typically associated with Ce-based scavengers. Particularly, the unique aspects of the Pt/CeO₂ scavenger synthesis could be summarized in the following points: (i) the mild aqueous deposition approach enabling highly dispersed Pt species on CeO₂ without the use of organic ligands; and (ii) the tailored redox interaction between Pt and ceria that enhances radical scavenging activity. Two Aquivion^® membranes (denoted Aqu) containing different syn-scavenger loadings (1.0 and 1.5 wt.%) were prepared and compared with a pristine Aquivion^® membrane and a membrane containing commercial CeO₂ (1.0 wt.%). Physicochemical characterization of the scavenger was performed using transmission electron microscopy (TEM), BET surface area analysis, and X-ray diffraction (XRD). The membranes were characterized by micro-Raman spectroscopy, water uptake and hydration number (λ), IEC, and proton conductivity measurements. To assess membrane stability, exsitu chemical oxidative degradation tests were conducted using Fenton’s reagent. Overall, the membrane containing 1.0 wt.% syn-scavenger emerged as the most promising candidate, exhibiting favourable chemical–physical properties and the lowest reductions in IEC and proton conductivity following the degradation test. Full article

A comprehensive study was conducted to determine the suitability of biochar produced from agricultural waste in the form of alfalfa (BL₅₀₀) and corn (BC₅₀₀) for methylene blue (MB) adsorption. As part of the research, biochar was produced at 500 °C by pyrolysis using a CO₂ atmosphere. BL₅₀₀ and BC₅₀₀ biochar were characterised in terms of their physicochemical and structural properties using FTIR spectroscopy, Raman spectroscopy, and N₂ adsorption–desorption. The produced biochars are characterised by a significant ash content and high carbon content. They have a specific surface area of 4.12 m²/g (BL₅₀₀) and 19.84 m²/g (BC₅₀₀), a micro-mesoporous structure and are rich in functional groups (including OH, COOH, CO). BL₅₀₀ biochar showed greater effectiveness in removing methylene blue (MB) than BC500, with maximum sorption capacities of 39.94 mg/g and 19.47 mg/g, respectively. Furthermore, kinetic model fitting indicated that the adsorption process follows a pseudo-second-order model and a Langmuir monolayer model. However, the intramolecular diffusion model (IPD) and Bangham models confirmed that the adsorption process does not occur in a single stage. The produced biochar can be used as a sustainable adsorbent for MB from aqueous solutions. Full article

Oral squamous cell carcinoma (OSCC) cytology involves extracting a cell sample consisting of single cells or small clusters of cells from patients’ head and neck area in order to identify abnormal morphological characteristics after staining it. This method is used to screen for early cancer and the formation of metastases within the oral cavity. OSCC diagnosis partly depends on pathologists’ skills and also laboratories’ instrumentation. The use of Raman spectroscopy could support diagnoses performed using traditional methods, providing information based on the cellular biochemical environment. Technical drawbacks related to low signal-to-noise ratios of Raman spectroscopy and the need to obtain diagnostic information within a reasonable time frame have recently led to the analysis of Raman spectra using machine learning (ML) methods in order to obtain reliable information about the correct attribution of unknown cellular spectra. So, we used Raman micro-spectroscopy combined with machine learning methods to build classification models, which allow the diagnosis of different grades of OSCC in cell samples. The Raman spectra were analysed in the 980–1800 cm⁻¹ range by focusing the laser beam onto the nucleus and the cytoplasm regions of single cells from different cell lines modelling healthy (HaCaT) and cancer (Cal-27, SAS and HSC-3) cytological samples. We considered six classification algorithms (k-Nearest Neighbours, Logistic Regression, Naïve Bayes, artificial Neural Network, Random Forest and Support Vector Machine) to classify unknown Raman spectra. We report two classification tasks: a 4-level classification, which encompasses healthy cells, two different types of cancer cells, and one type of metastatic cells, and a 3-level classification, which includes healthy cells, non-metastatic cancer cells, and metastatic cancer cells. Our findings show that both Neural Network and Support Vector Machine algorithms applied to Raman spectra measured in the cytoplasm region can achieve sensitivity, precision and F1-score values larger than 90% in the 3-groups classifications, whereas Support Vector Machine performs better in the 4-groups classification with respect to a Neural Network. These results contribute to increasing confidence in the clinical translation of ML-assisted Raman spectroscopy as a tool to support conventional cytological techniques. Full article

“Heijin” (the literal translation from Chinese being “Black Gold”) seal stone represents a unique variety of sulfur-rich, dickite-dominant jade, yet its mineralogical genesis and structural properties remain insufficiently characterized. This study utilizes a multi-analytical approach comprising polarized light microscopy, X-Ray diffraction (XRD), Raman spectroscopy, Fourier-transform infrared spectroscopy (FTIR), Scanning Electron Microscopy coupled with Energy-Dispersive X-Ray Spectroscopy (SEM-EDS), Electron Probe Microanalysis (EPMA), and Thermogravimetry and Differential Scanning Calorimetry (TG-DSC) to investigate the phase composition, crystalline order, and thermal evolution of this material. The results demonstrate that “Heijin” stone is primarily composed of highly ordered 2M₁ dickite with a Hinckley index (HI) ranging from 0.92 to 1.50. Its distinctive black appearance originates from the disseminated distribution of micrometer-scale pyrite, which is accompanied by trace amounts of svanbergite. This aluminum phosphate–sulfate (APS) mineral serves as a critical indicator of high sulfur fugacity and acidic hydrothermal alteration environments. Furthermore, a significant correlation exists between the crystalline order of dickite, its micro-morphology, and its thermal stability. Samples characterized by high crystallinity (HI ≈ 1.50) exhibit well-developed, euhedral book-like aggregates and elevated dehydroxylation temperatures (T_m ≈ 665 °C), whereas samples with lower crystalline order correspond to fragmented microstructures and reduced thermal stability. This research defines the mineralogical identity of “Heijin” stone and provides a scientific basis for employing thermal analysis to evaluate the crystalline quality of dickite-based jade materials. Full article

Heart failure with preserved ejection fraction (HFpEF) is a complex and heterogeneous syndrome characterized by delayed diagnosis and limited therapeutic options, contributing to poor clinical outcomes. In the present study, we investigated the applicability of Raman micro-spectroscopy (RmS) as a label-free, rapid, and cost-effective approach for identifying molecular signatures associated with HFpEF and enabling reliable disease classification. RmS was applied to evaluate disease-related biochemical alterations in cardiac and renal tissues obtained from a clinically relevant HFpEF model (ZSF1 rat). Furthermore, the effects of three pharmacological interventions were analyzed and classified (five experimental groups—36 animals in total), highlighting organ-specific therapeutic responses. We developed a spectroscopic data analysis strategy in which second-derivative Raman spectral features serve as quantitative inputs to a supervised classification model, enabling micro-spectroscopic discrimination of HFpEF versus control tissues and achieving a classification accuracy of 92% (sensitivity 93% and specificity 91%) based on the protein-to-tryptophan ratio in cardiac tissue, while minimizing the need for extensive data preprocessing. The spectroscopic markers used in this study were derived from prior multivariate discovery analyses and are evaluated here within a validation and translational classification framework. Collectively, these findings support the integration of RmS into molecular and translational research settings and suggest its potential utility for improving HFpEF diagnosis and treatment monitoring. Full article

Objective: The aim of this study was to summarize the accuracy and efficacy of Raman spectroscopy (RS) technology in identifying Oral Potentially Malignant Disorders (OPMDs). Methods: This systematic review was registered in PROSPERO (CRD420251124866). A literature search was conducted in databases including PubMed, Embase, and Web of Science from inception up to September 2025. The risk of bias of included studies was evaluated using the QUADAS-2 tool. Appropriate statistical techniques were applied to perform heterogeneity analysis, subgroup analyses, and calculation of pooled diagnostic efficacy indices. Results: A total of 12 studies involving 2810 samples were included. In the “OPMDs vs. Normal” group, RS achieved a pooled sensitivity of 0.84 (95% CI: 0.78–0.88), specificity of 0.90 (95% CI: 0.73–0.97), and AUC of 0.89 (95% CI: 0.86–0.91). In the “OPMDs vs. Oral squamous cell carcinoma (OSCC)” group, the pooled sensitivity was 0.89 (95% CI: 0.82–0.94), specificity was 0.91 (95% CI: 0.85–0.95), and AUC was 0.94 (95% CI: 0.91–0.96). Heterogeneity analysis revealed low heterogeneity in the “OPMDs vs. OSCC” group (I² = 22.8%) and moderate heterogeneity in the “OPMDs vs. Normal oral mucosa” group (I² = 58.9%). Subgroup analyses were performed: sample type exerted no significant impact on heterogeneity (p > 0.19), while Raman type (micro vs. fiber) showed potential to modulate diagnostic efficacy, micro-Raman had higher sensitivity (0.916 vs. 0.811), and fiber-Raman had better specificity (0.917 vs. 0.843). No significant publication bias was observed (Egger’s p > 0.3). Conclusions: Raman spectroscopy is an effective and reliable tool for screening and differentiating OPMDs. Full article

In this work, the deposition of graphene coatings on substrates of an ELI grade Ti-6Al-4V alloy was carried out using the Plasma Enhanced Chemical Vapor Deposition (PECVD) technique. The purpose of this study was to improve the surface properties of the material. The characterization of the material was carried out by non-destructive techniques, such as Raman Spectroscopy and Thermoelectric Potential. A preliminary characterization of Ti substrates was carried out by Raman spectroscopy. Conversely, thermoelectric potential tests were conducted using three distinct tip systems and four different temperature gradients. Lastly, some surface roughness measurements were conducted on all samples, both coated and uncoated. Graphene micro-structured coatings were obtained using a plasma-activated mixture of hydrogen and methane gases with an equimolar feed ratio (1:1 H₂:CH₄) at a temperature of 850 °C and a plasma exposure of 150 Watts and duration of 15 min. Raman spectra verified the presence of uniform micrometric graphene on the surface of Ti substrates. Graphene-coated Ti-6Al-4V ELI substrates exhibited Seebeck coefficient values indicating metallic-like behavior and suitability for thermoelectric sensing. In the eddy current analyses, it was found that low frequencies provided the highest sensitivity for differentiating between samples. An inverse relationship was identified between substrate thickness and phase angle, and a direct relationship with calculated electrical conductivity was also identified. This direct relation is attributed to penetration depth and interactions due to the chemical nature of the substrate and coating. Despite a slight increase in surface roughness after graphene deposition, values remained comparable to the base alloy, preserving compatibility for biomedical integration. Thermoelectric potential measurements revealed enhanced sensitivity to surface morphology and interfacial effects when high-sensitivity probe configurations were employed. These results support potential applications in implantable or wearable temperature sensors, energy harvesting devices, and smart biomedical interfaces. The thickness of the graphene coating was also characterized by SEM, which showed that the films deposited by PECVD are about 1 micron thick. Full article

In response to thermal failure risks in ultra-high voltage (UHV) bushing online monitoring devices and maintenance equipment—caused by high heat generation of electronic components and the intrinsically low thermal conductivity of conventional resin encapsulation materials—this study proposes a novel modification strategy based on flash Joule heating (FJH). Distinct from conventional interface modification methods, the proposed approach enables cross-scale, in situ microsoldering between multi-walled carbon nanotubes (MWCNTs) and carbon fibers (CFs), constructing a multiscale reinforcement network with integrated thermal transport and mechanical load transfer pathways. The transient ultra-high-temperature thermal shock generated by FJH not only effectively removes inert impurities on CF surfaces but also drives carbon structural reconstruction, enabling graphitic-level welding of MWCNTs onto the fiber surface. This micro-welded architecture fundamentally differs from traditional filler dispersion or interface coating strategies, which often suffer from the trade-off between interfacial thermal transport and mechanical bonding. By contrast, the FJH-induced carbon–carbon bonded nodes form a continuous conductive and load-bearing network at the micro–nano scale. Characterizations using scanning electron microscopy (SEM), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS) confirm successful in situ welding of MWCNTs onto CF surfaces. Meanwhile, FJH treatment effectively removes oxygen-containing functional groups and surface impurities. Analysis of carbon bonding evolution indicates that the welding efficiency reaches its maximum at 90 V. Macroscopic performance tests demonstrate that, compared with epoxy resin, the thermal conductivity of the multiscale reinforced system increases by approximately 168%, while the mechanical strength improves by 62.72%. This study provides new theoretical insights and technical pathways for the development of next-generation polymer composite materials with both high thermal conductivity and high mechanical strength. Full article