Search Results (62)

Uveal melanoma is the most common primary intraocular malignancy in adults, most frequently arising from the choroid, followed by the ciliary body and iris. Its diagnosis and management require precise characterization of tumor morphology, localization, and associated complications to optimize visual and systemic outcomes. Recent advances in optical coherence tomography (OCT), anterior segment OCT (AS-OCT), and OCT angiography (OCTA) have expanded the ophthalmologist’s ability to non-invasively visualize structural and vascular changes associated with this disease. In fact, enhanced depth imaging (EDI) and swept-source (SS) OCT can provide detailed views of deep ocular structures, enabling early detection of hallmark features such as subretinal fluid, retinal pigment epithelium disruption, and dome- or mushroom-shaped choroidal elevations; AS-OCT improves evaluation of lesions of the anterior segment, revealing iris architecture distortion and angle involvement; OCTA facilitates the visualization of abnormal tumor vasculature and detection of radiation-induced microvascular changes, including capillary dropout and foveal avascular zone enlargement. Moreover, these imaging modalities have demonstrated utility in differentiating uveal melanoma from pseudomelanomas, such as choroidal nevi, hemangiomas, and metastases. The present review aims at objectively assessing the use of OCT and OCTA in the diagnosis, treatment, and follow up of ocular melanoma, emphasizing their crucial role in identifying pathologic biomarkers of this potentially fatal ocular disease. Full article

The findings of non-invasive, multi-analytical research on two wall paintings located in the Santuario della Beata Vergine dei Miracoli in Saronno (Varese, Italy)—The Marriage of the Virgin and The Adoration of the Christ Child—are presented in this paper. The authorship of the latter is up for controversy, while the former is unquestionably attributed to Bernardino Luini. The objective was to assess the compatibility of their color palettes through material comparison. A complementary suite of non-invasive techniques, including X-ray fluorescence (XRF), external reflection FTIR, Raman, visible reflectance spectroscopy and hyperspectral imaging, were employed to characterize pigments and surface materials without sampling. Results confirm the use of historically consistent pigments such as calcium carbonate, ochres, Naples yellow, smalt, azurite and lapis lazuli. Differences in the application of blue pigments—lapis lazuli in The Marriage of the Virgin and azurite in The Adoration of the Christ Child—may reflect workshop variation rather than separate authorship. Spectral imaging revealed pigment mixing and layering strategies, especially in skin tones and shadow modeling. This study underscores the significance of diagnostics as an interpretive instrument, capable of contextualizing Luini’s paintings within the context of Renaissance creative practice, providing a framework relevant to analogous inquiries. Full article

Plant gums have long served as essential binding media in polychrome cultural heritage, contributing to pigment adhesion, surface cohesion, and long-term stability. This review evaluates recent advances in analytical technologies, including FTIR, Raman spectroscopy, GC-MS, LC-MS/MS, MALDI-TOF MS, hyperspectral imaging, and immunological assays, for the identification of gums such as gum arabic, peach gum, and tragacanth in diverse cultural contexts. Drawing on case studies from 19th-century watercolours, ancient Egyptian coffins, and Maya murals, the paper demonstrates how these methods enable precise chemical characterization even in complex, aged, and mineral-rich matrices. Such information directly aids conservators in selecting compatible restoration materials, tailoring treatment protocols, and assessing deterioration mechanisms. Persistent challenges remain, including gum degradation, spectral interference from pigments and restoration materials, sample heterogeneity, and limited reference libraries, particularly for non-European species. Future research directions emphasize multi-modal, non-invasive workflows that integrate hyperspectral imaging with spectroscopic and chromatographic methods, drone-assisted micro-Raman for inaccessible surfaces, machine learning-assisted spectral databases, and bio-inspired adhesives replicating historical rheology. By linking molecular identification to conservation decision-making, plant gum analysis not only deepens our understanding of historical material practices but also strengthens the scientific basis for sustainable heritage preservation strategies. Full article

Ten ukiyo-e woodblock prints from the collection of the Museo delle Culture in Lugano (Switzerland) were analyzed to identify the materials used in their production. These Japanese artworks were traditionally created with colors derived from minerals and plants, mixed with diluted animal glue and applied to paper using wooden matrices. Due to their fragility, non-invasive external reflection infrared spectroscopy and imaging analysis were employed. Spectral data were compared with reference samples of Japanese pigments and existing literature, reflecting the growing interest in the characterization of ukiyo-e prints. Within the limits of the non-invasive approach, several colorants were identified, including akane (madder), suo (sappanwood), yamahaji (Japanese sumac), kariyasu (Eulalia), and kio (orpiment), along with a proteinaceous binding medium. The extensive use of bero-ai (Prussian blue), applied both as a pure pigment and in mixtures, was confirmed. Notably, mica was detected in the background of one print, providing the first analytical evidence of the kirazuri decorative technique, which produces a sparkling, silver-like effect. Ultraviolet-induced fluorescence imaging further contributed to the assessment of conservation status, revealing faded decorative motifs and signs of previous water damage. Full article

Background: Age-related macular degeneration (AMD) is one of the leading causes of permanent vision loss in the elderly, particularly in higher-income countries. Fundus autofluorescence (FAF) imaging is a widely used, non-invasive technique that complements structural imaging in the assessment of retinal pigment epithelium (RPE) integrity. While optical coherence tomography (OCT) remains the gold standard for retinal imaging due to its high-resolution cross-sectional visualization, FAF offers unique metabolic insights. Among the FAF modalities, blue light FAF (B-FAF) is more commonly employed, whereas green light FAF (G-FAF) provides subtly different image characteristics, particularly improved visualization and contrast in the central macula. Despite identical acquisition times and nearly indistinguishable workflows, G-FAF is notably underutilized in clinical practice. Objectives: This narrative review critically compares green and blue FAF in terms of their diagnostic utility relative to OCT, with a focus on lesion detectability, macular pigment interference, and clinical decision-making in retinal disorders. Methods: A comprehensive literature search was performed using the PubMed database for studies published prior to February 2025. The search utilized the keywords fundus autofluorescence and age-related macular degeneration. The primary focus was on short-wavelength FAF and its clinical utility in AMD, considering three aspects: diagnosis, follow-up, and prognosis. The OCT findings served as the reference standard for anatomical correlation and diagnostic accuracy. Results: Both FAF modalities correlated well with OCT in detecting RPE abnormalities. G-FAF demonstrated improved visibility of central lesions due to reduced masking by macular pigment and enhanced contrast in the macula. However, clinical preference remained skewed toward B-FAF, driven more by tradition and device default settings than by evidence-based superiority. G-FAF’s diagnostic potential remains underrecognized despite its comparable practicality and subtle imaging advantages specifically for AMD patients. AMD stages were accurately characterized, and relevant images were used to highlight the significance of G-FAF and B-FAF in the examination of AMD patients. Conclusions: While OCT remains the gold standard, FAF provides complementary information that can guide management strategy. Since G-FAF is functionally equivalent in acquisition, it offers slight advantages. Broader awareness and more frequent integration of G-FAF that could optimize multimodal imaging strategies, particularly in the intermediate stage, should be developed. Full article

In recent decades, there has been an increase in the development of non-invasive and non-destructive analytical techniques in the field of cultural heritage. The present study aims to characterize the frescoes in the hypogeum environment of the San Pietro a Corte complex in Salerno (Campania, Italy) through a multi-analytical approach that couples Infrared Reflectography with X-Ray Fluorescence Spectrometry. Thermographic and hygrometric measurements were also performed to evaluate their state of conservation in relation to environmental parameters such as relative humidity and temperature at the frescoed walls. Spectroscopic investigations revealed a predominant use of natural pigments—chiefly iron-rich earths—and uncovered details invisible to the naked eye that aid art historians in refining stylistic attributions. Hygrometric data showed that the central zones of the frescoes retain the highest moisture levels, underscoring the need for a carefully tailored conservation plan. Overall, this multi-analytical methodology provides important information that enables conservators and restorers to understand both the materials and the preservation requirements of these artworks from a scientific and conservation perspective. Full article

Twelve sherds of blue-and-white Chinese porcelains recovered from archaeological excavations in the Santana Convent (Ming and Qing Dynasties) in Lisbon were studied using several non-invasive spectroscopies, namely micro-Raman, X-ray Fluorescence (XRF), Ground State Diffuse Reflectance (GSDR), and stereomicroscopy. The use of the X-ray diffraction technique (XRD) allowed us to complete the mineralogical characterization of the ceramic bodies and glazes of the porcelains. The sample selection ranges from the 16th to the 18th centuries. The micro-Raman spectra clearly showed two types of glazes, alkaline glaze and calcium-based glaze. The GSDR absorption spectra of the blue glazes point to the use of different cobalt pigments, but a strong dependence on the glaze type does not seem to exist. The kilns where the porcelains were produced also play an important role. Both the GSDR absorption and the micro-Raman spectroscopies allow us to differentiate the Iranian blue pigment from the Chinese pigment. A direct and simple correlation between the use of Iranian blue pigment, mixtures of Iranian and Chinese pigments, or simply Chinese pigments and the stylistic dating of each sample was established. Furthermore, several important spectroscopic characterizations could be achieved in this study. Full article

Background: Adaptive optics transscleral flood illumination (AO-TFI) enables in vivo, non-invasive, high-resolution imaging of retinal pigment epithelium (RPE) and photoreceptor (PR) cells, paving the way for a new potential characterization of retinal diseases. This study aimed to analyze RPE and PR cells in a case of acute zonal occult outer retinopathy (AZOOR) using AO-TFI. Methods: A patient affected by AZOOR underwent a comprehensive eye examination, perimetry, electroretinography (ERG), autofluorescence, and optical coherence tomography (OCT) during the acute phase (T0). After three years (T1), OCT angiography (OCTA) and AO-TFI were also performed. Voronoi analysis was utilized to quantify RPE and PR cells. Results: At T0, OCT revealed interruptions in the ellipsoid zone (EZ) of the right eye, while the structure of the left eye appeared normal. Perimetry and ERG were abnormal in both eyes. At T1, OCT indicated recovery of the EZ in the right eye, while thinning of the ONL persisted. Perimetry and mfERG values remained below normative limits. OCTA exhibited globally reduced vessel density in the inner retina of the right eye. AO-TFI demonstrated reduced PR density in affected areas despite preserved EZ, while RPE cell density appeared unaffected. Conclusion: AO-TFI enabled a detailed visualization and quantification of macular RPE and PR cells, providing valuable insights into the pathophysiology of AZOOR. Full article

This communication presents an approach to the chromatic study of rock painting scenes in the Tecsecocha sector, Ccorca district, Cusco, Peru, through the application of color spectrophotometry using Capsure by XRite, considered a portable device that facilitates reference measurements of color codes belonging to the visible spectrum (400–700 nm). It is evident that this methodology does not perform the physicochemical characterization of the pigments present in the rock paintings, which are cataloged as artistic heritage of the nation, making it unfeasible to extract physical samples or significantly alter the rock paintings. Therefore, the NCS color notation system allowed for the non-invasive recording of color tones. The results showed a predominance of white and red tones with variations in their shades; among the most frequent codes, S2030-Y70R and S3010-Y40R stand out, indicating yellow tones with red influences of 70% and 40%, respectively. In the anthropomorphic figures, a slight variation in the proportion of red was identified, suggesting differences in the application of pigments, while in the representations of camelids, the tones varied from S3005-Y20R (yellow with 20% red) to S2030-Y70R (greater red influence). Full article

The invasive aquatic macrophyte Pontederia crassipes (water hyacinth) exhibits exceptional adaptability across a wide range of light environments, yet the mechanistic basis of its photosynthetic plasticity under both high- and low-light stress remains poorly resolved. This study integrated chlorophyll fluorescence and gas-exchange analyses to evaluate three photosynthetic models—rectangular hyperbola (RH), non-rectangular hyperbola (NRH), and the Ye mechanistic model—in capturing light-response dynamics in P. crassipes. The Ye model provided superior accuracy (R² > 0.996) in simulating the net photosynthetic rate (P_n) and electron transport rate (J), outperforming empirical models that overestimated P_nmax by 36–46% and J_max by 1.5–24.7% and failed to predict saturation light intensity. Mechanistic analysis revealed that P. crassipes maintains high photosynthetic efficiency in low light (LUE_max = 0.030 mol mol⁻¹ at 200 µmol photons m⁻² s⁻¹) and robust photoprotection under strong light (NPQ_max = 1.375, PSII efficiency decline), supported by a large photosynthetic pigment pool (9.46 × 10¹⁶ molecules m⁻²) and high eigen-absorption cross-section (1.91 × 10⁻²¹ m²). Unlike terrestrial plants, its floating leaves experience enhanced irradiance due to water-surface reflection and are decoupled from water limitation via submerged root uptake, enabling flexible stomatal and energy regulation. Distinct thresholds for carboxylation efficiency (CE_max = 0.085 mol m⁻² s⁻¹) and water-use efficiency (WUE_i-max = 45.91 μmol mol⁻¹ and WUE_inst = 1.96 μmol mmol⁻¹) highlighted its flexible energy management strategies. These results establish the Ye model as a reliable tool for characterizing aquatic photosynthesis and reveal how P. crassipes balances light harvesting and dissipation to thrive in fluctuating environments. These resulting insights have implications for both understanding invasiveness and managing eutrophic aquatic systems. Full article

The present study explores a multi-analytical non-invasive approach based on the application of terahertz continuous wave (THz-CW) spectroscopy for the non-invasive characterization of historically produced synthetic copper silicate pigments. For the first time, Han Blue, Han Purple and Egyptian Blue were examined within the THz spectral region using a compact and portable THz-CW spectrometer. The three pigments exhibit distinct absorption features, which facilitate the differentiation of molecular structures within the same chemical and mineralogical category. Moreover, the same compound was analyzed using Energy Dispersive X-Ray Fluorescence (ED-XRF) to determine its elemental composition, alongside Fiber Optics Reflectance Spectroscopy (FORS) in the range 350–2500 nm, providing crucial insights into its optical properties and molecular structure. To the best of the authors’ knowledge, the present study presents the first spectra for these copper silicates at these wavelengths, thereby expanding the shortwave infrared spectral database of Cultural Heritage materials. This synergistic approach enables a comprehensive characterization, offering a deeper understanding of the compounds’ chemical nature and paving the way for potential applications in the Cultural Heritage domain. Furthermore, the findings underscore the potential of THz-CW spectroscopy as an innovative and effective tool for Cultural Heritage research, providing a non-destructive method to investigate artistic materials. Full article

Raman spectroscopy is a spectral analysis technique based on molecular vibration. It has gained widespread acceptance as a practical tool for the non-invasive and rapid characterization or identification of multiple analytes and compounds in recent years. In fruit quality detection, Raman spectroscopy is employed to detect organic compounds, such as pigments, phenols, and sugars, as well as to analyze the molecular structures of specific chemical bonds or functional groups, providing valuable insights into fruit disease detection, pesticide residue analysis, and origin identification. Consequently, Raman spectroscopy techniques have demonstrated significant potential in agri-food analysis across various domains. Notably, the frontier of Raman spectroscopy is experiencing a surge in machine learning applications to enhance the resolution and quality of the resulting spectra. This paper reviews the fundamental principles and recent advancements in Raman spectroscopy and explores data processing techniques that use machine learning in Raman spectroscopy, with a focus on its applications in detecting fruit diseases, analyzing pesticide residues, and identifying origins. Finally, it highlights the challenges and future prospects of Raman spectroscopy, offering an effective reference for fruit quality detection. Full article

This article offers a discussion of the possibility of distinguishing ochres from Mars pigments. The discussion addresses technological, archaeological, and artistic aspects. Natural earth pigments such as ochres, siennas, and umbers have been widely used from the Paleolithic to the present day and still find wide application despite the development of synthetic iron oxide pigment synthesis processes, called Mars pigments. The potential ability of today’s analytical techniques to distinguish between two classes of pigments of the same color with very similar chemical composition—but perhaps sufficient for reliable recognition—is also discussed. The paper begins by addressing the proper use of the terms “ochres” and “Mars pigments” and their accurate identification in artworks. It reviews the literature on the chemical–mineralogical characterization of yellow and red iron pigments and analyzes pigment catalogs to understand how companies distinguish ochres from Mars pigments. An experimental analysis using External Reflection Infrared Spectroscopy (FTIR-ER) compared painting samples made with natural ochres and Mars pigments, confirming the literature findings and suggesting future research directions. Key differences such as hematite in yellow ochres and specific spectral peaks in red ochres support the potential of FTIR-ER spectroscopy as a noninvasive tool for distinguishing pigments, especially for fragile artifacts and archaeological applications. Full article

The ancient Roman town of Turris Libisonis was located on the northern coast of Sardinia and was known in the past as an important naval port. Located in the Gulf of Asinara, it was a Roman colony from the 1st century BCE and became one of the richest towns on the island. Among the archaeological finds in the area, the cippus exhibited in the Antiquarium Turritano is of great interest for its well-preserved traces of polychromy. The artefact dates back to the early Imperial Age and could have had a funerary or votive function. The artefact was first examined using a portable and non-invasive protocol involving multi-band imaging (MBI), portable X-ray fluorescence (p-XRF), portable FT-IR in external reflectance mode (ER FT-IR) and Raman spectroscopy. After this initial examination, a few microfragments were collected and investigated by optical microscopy (OM), X-ray powder diffraction (XRPD), Fourier-transform infrared spectroscopy in ATR mode (ATR FT-IR) and micro-ATR mode (μATR FT-IR) and Scanning Electron Microscopy/Energy Dispersive Spectroscopy (SEM-EDS) to improve our knowledge and characterize the materials and to determine their provenience. The results contribute to a better understanding of the provenance of materials and shed light on pigments on stone and their use outside the Italian peninsula and, in particular, Roman Sardinia. Full article

Even though X-ray fluorescence (XRF) is strictly an atomic method, this technique has been developed mostly at research centers for nuclear physics. One of its most valuable variations is the mapping mode that allows it to shift XRF from a punctual to an image technique. Macro X-ray Fluorescence (MA-XRF) is a widespread analytical technique applied in cultural heritage for characterizing the elemental composition of pigments with a non-destructive, rapid and green approach. When dealing with cultural heritage materials, the sustainability of the applied techniques is directly linked to the limited impact on the work of art. MA-XRF can reveal hidden sub-surface layers or restorations, but, nonetheless, it is hardly adopted for estimating the thickness of layers without resorting to complex Monte Carlo simulations or without combining information from other techniques. Exploiting the recurrent presence of lead white under pictorial layers in historical artworks, we perform a calibration on stand-alone layers produced ad hoc for the relative absorption of Pb L fluorescence lines, and then, their ratio is successfully used to estimate the thickness of azurite and ultramarine blue layers over lead white. The final result is rendered as a heatmap, easy to present to non-technical personnel frequently involved in the cultural heritage field. The new proposed procedure for calculating layer thickness extends the concept of non-invasive applications, paving the way to the possibility of performing stratigraphy without sampling. Full article