Heavy metals such as copper and zinc serve as essential trace elements for photosynthetic organisms at appropriate concentrations. However, at elevated levels, these metals (along with non-essential metals like chromium, lead, mercury, and cadmium) exert severe toxic effects on aquatic life. Heavy metal toxicity primarily relates to oxidative damage in living systems through a direct increase in reactive oxygen species (ROS) and reduction in cellular antioxidant capacity. Previous research on algae of different types with different coverings led us to complete the comparative framework. For this purpose and to assess biotechnological potential, we investigated chromium effects on Euglena gracilis, which possesses a unique pellicle covering, to determine whether it could serve as a chromium biosensor or bioremediation agent. Using Raman spectroscopy and absorption microspectrophotometry (MSP), we found that chromium concentrations of up to 500 mu M had no effect on Euglena chlorophyll or carotenoid profiles, consistent with the pellicle preventing chromium entry and protecting the photosynthetic apparatus. However, concentrations > 10 mu M severely inhibited growth through extracellular interference with essential nutrient utilization (ammonium phosphate and vitamin B-12). Growth inhibition was reversible upon transfer to fresh medium, confirming that cellular machinery remained intact. These results suggest that E. gracilis cannot serve as a chromium biosensor (photosynthetic apparatus unaffected) or bioremediation agent (no chromium internalization), but its ability to maintain photosynthetic functionality in chromium-contaminated environments suggests the potential for alternative applications in polluted water biomass production.

In this study, we report the development and comprehensive characterization of novel poly(lactic-co-glycolic acid) (PLGA)-based nanocomposites incorporating phosphorene nanoflakes. Phosphorene was produced by ultrasound-assisted exfoliation of black phosphorus in the presence of sodium dodecyl sulfate (SDS) as a surfactant, and was then subsequently embedded into a PLGA matrix to fabricate phosphorene-PLGA nanocomposite films, prepared here for the first time, and emulsions. The structural, thermal, and photophysical properties of these hybrid materials were systematically investigated, with a focus on the interfacial interactions between the polymer matrix and the 2D nanofillers. The integration of phosphorene nanosheets significantly enhances the thermal stability of PLGA at elevated temperatures (with a notable shift of similar to 40 degrees C), while slightly accelerating its hydrolytic degradation at lower temperatures, resulting in a similar to 20 % reduction in molecular weight. More interestingly, the PLGA matrix plays a protective role, mitigating the degradation of phosphorene during the polymer hydrolytic degradation. Importantly, we study for the first time the photophysical behaviour of phosphorene nanoflakes embedded in PLGA emulsions, highlighting their potential for photodynamic therapy (PDT) applications. While free phosphorene nanoflakes exhibit outstanding photocatalytic activity in generating singlet oxygen, their embedding within PLGA micelles causes a marked suppression (similar to 90 %) of this activity, likely due to restricted oxygen diffusion in the polymeric environment. This previously unreported limitation is crucial for evaluating the applicability of phosphorene-PLGA systems in biomedical contexts, particularly in PDT.

The study of ancient sculptural polychromy increasingly relies on non-invasive analytical approaches capable of identifying pigments and reconstructing original decorative schemes while preserving the integrity of archaeological objects. This paper presents the investigation of the polychromy, extraordinarily preserved, on two Roman marble statues discovered in the forum of Formia (southern Latium) and currently housed in the National Archaeological Museum of Formia: a togate statue (inv. 147614) and a headless draped female figure (inv. 147680). Both sculptures retain exceptionally well-preserved traces of pigments, offering a rare opportunity to investigate materials and painting techniques applied to Roman marble statuary. The analytical protocol combined multiband imaging (Visible-Induced Luminescence and Ultraviolet Luminescence), optical microscopy, Fiber Optic Reflectance Spectroscopy (FORS), portable X-ray Fluorescence (XRF), and Surface Enhanced Raman Spectroscopy (Raman-SERS) applied to two micro-samples. The analyses allowed the identification of Egyptian blue, iron-based pigments, gilding, and an organic red lake on the palettes used for the statues. Raman-SERS measurements provided additional information on the composition of the organic lake detected on the female statue’s himation, supporting its attribution to a natural vegetal-derived dye, as madder lake. The results highlight the success of integrated non-destructive methodologies for the study of Roman sculptural polychromy and contribute to the reconstruction of complex decorative schemes on marble statuary.

LIBS is emerging as a powerful technique for phosphorus analysis in agricultural, environmental and industrial applications. This review critically discusses recent advances, current limitations and future strategies for robust quantitative analysis.

This work responds to the objective of recovering, preserving and valorising ancient documents, with particular reference to those in Arabic, both manuscripts and small objects with Arabic inscriptions of significant historical-cultural interest, preserved in libraries and historical archives. The proposed approach aims to scientifically analyse both the form and content of the selected material in order to provide input for its conservation, digitisation, archiving, annotation and large-scale exploitation. To this end, the most advanced diagnostic and digital technologies will be adopted, integrated and tested with the aim of valorising and translating the uniqueness of the material objects into a format suitable for management and manipulation in innovative digital environments, while preserving all their complexity as objects of scientific analysis in the field of historical-cultural studies. The study presented here concerns the preliminary analysis of a copy of sacred texts in Arabic, Ms 566, dating from around the 15th century and currently held at the Biblioteca Nazionale of Pisa. The manuscript was chosen because it is representative of the material typology, state of preservation and content of the ancient manuscript, epigraphic and book heritage of the Arab world.

Enrico Van Lint (Pisa, 1808–1884) was a very prolific photographer, active in Pisa in the 19th century where he had a prominent photographic atelier. He was a meticulous experimenter, investigating the evolving photographic activity of his historical period. While his early works included calotypes using Fox Talbot’s methods, he rapidly adopted the collodion processes, becoming one of the most important Italian photographers that used this technique. At the present time, a vast number of examples of the works from Van Lint’s ateliers are preserved and archived in Pisa, under the supervision of the Italian Ministry of Culture in the Photographic Archive of the “Soprintendenza Archeologia, Belle Arti e Paesaggio per le provincie di Pisa e Livorno” (SABAP). This collection is composed of positive prints as well as glass plate negatives, from both Van Lint himself and his colleagues. To this day, Van Lint’s collection has not been studied using analytical techniques, and the identification of the photographic processes involved in the preparation of the positive prints has relied exclusively on thorough observation by historians and conservators. This provides a unique occasion for a first study of Van Lint’s collection, using multiple non-invasive and non-destructive techniques (multispectral imaging, XRF, and FTIR) that can identify the photographic process used to make the positives, as well as highlight significant differences or degradation phenomena. In this preliminary work, we investigated a selection of ten positive prints, attributed to both Van Lint himself and later reproductions from the original glass negatives. The selected samples include prints previously classified as albumen prints and gelatin prints, displaying slight differences in conservation status as well as in print finish. This analytical approach allowed for a proper characterization of these Van Lint’s prints, improving the historical and conservation knowledge to implement the best preventive preservation actions in the near future.

Although approximately half of global lithium consumption is used in the rechargeable battery industry, lithium is also in demand for other specialized applications, such as high-temperature lubricants, ceramics, glass, and pharmaceuticals. The growing need for efficient lithium recovery and recycling underscores the importance of fast and accurate analytical tools for determining lithium concentrations in non-compliant and waste materials generated by industrial processes. In this paper, we present a machine learning-based procedure utilizing Laser-Induced Breakdown Spectroscopy (LIBS) to accurately quantify lithium concentrations in lithium-rich non-compliant materials derived from the industrial production of enamels used for coating metallic surfaces. This procedure addresses challenges such as strong self-absorption and matrix effects, which limit the effectiveness of conventional univariate calibration methods. By employing a multivariate approach, we developed a single model capable of quantifying lithium content across a wide concentration range. A comparison of the LIBS results with those obtained using conventional laboratory analysis (Inductively Coupled Plasma–Optical Emission Spectrometry, ICP-OES) confirms that LIBS can deliver the speed, precision, and reliability required for potential routine applications in the lithium recovery and recycling industry.

Lithium has emerged as a pivotal material for the global energy transition, yet its supply security is challenged by limited geographical availability and growing demand. These constraints highlight the need for analytical methods that are not only accurate but also sustainable and deployable across the entire lithium value chain. In this context, Laser-Induced Breakdown Spectroscopy (LIBS) offers distinctive advantages, including minimal sample preparation, real-time and in situ analysis and the potential for portable and automated implementation. Such features make LIBS a valuable tool for monitoring and optimizing lithium extraction, refining and recycling processes. This review critically examines the recent progress in the use of LIBS for lithium detection and quantification in geological, industrial, biological and extraterrestrial matrices. It also discusses emerging applications in closed-loop recycling and highlights future prospects related to the integration of LIBS with artificial intelligence and machine learning to enhance analytical accuracy and material classification.

The recent restoration of the painting "Enthroned Virgin Mary with Child, St. John the Baptist, St. Francis, St. Bartholomew and St. Jerome" (also known as "Madonna delle Grazie"- Oil on wood , 235 x 194 cm) carried out by the restorers of the Opera del Duomo in Pisa (2020-2021) provided the occasion for a multi-analytical study of this sixteenth-century masterpiece. We learn from Vasari's Lives of the Artists that the panel was commissioned to Andrea del Sarto (Andrea d'Agnolo, Florence 1486 - Florence 1530) by the friars of the Monastery of St. Francis in Pisa. The painting was left unfinished by Andrea del Sarto due to his sudden death during the plague in Florence in 1530 and was completed eight years later by Giovanni Antonio Sogliani (Florence, 1492 - Florence, 1544). The division of work between Andrea del Sarto and Sogliani in the painting remains a subject of debate. Art historians have largely agreed on the hypothesis that almost the entire painted surface, should be attributed to Sogliani. However, the attribution of the composition is still controversial; it is unclear whether the design is entirely by Andrea del Sarto, or if certain parts were reinterpreted by Giovanni Antonio Sogliani. To contribute analytical data to this debate, a novel multispectral approach incorporating the Interesting Feature Finding (IFF) method was utilized to examine the painting. Additionally, energy-dispersive Xray fluorescence (ED-XRF) and micro-Raman analyses were conducted to characterise the pigments used by the artist(s) in different parts of the masterpiece. The multispectral analysis revealed significant differences between the underdrawings - potentially attributable to Andrea del Sarto - and the painted surface. The ED-XRF and micro-Raman results do not exclude the possibility that parts of the painting were executed by del Sarto. The IFF method also uncovered several "pentimenti ", including a small (human?) figure, which opened intriguing comparisons with other works by Andrea del Sarto. (c) 2024 The Author(s). Published by Elsevier Masson SAS. This is an open access article under the CC BY license ( http://creativecommons.org/licenses/by/4.0/ )

Codex 462 of the Fondo Hortus Pisanus of the Biblioteca Universitaria of Pisa is a precious example of a 16th century illustrated herbal, Icones variarum plantarum, containing 35 tempera paintings by the German soldier Georg Dyckman, an amateur but highly talented artist. The manuscript was recently restored on the occasion of an international exhibition; the necessary preliminary studies for the restoration included a series of in situ diagnostic studies using contactless techniques (digital microscope, multispectral imaging, XRF, Raman and ER-FTIR). These analyses proved useful in deepening the knowledge of the materials and the execution technique of this type of illustrated herbals and in choosing the most appropriate solutions during the restoration phase. In view of the growing interest in this type of historical evidence, which involves both art history and the history of science, this study offers an interesting new perspective on the subject, useful both from a technical point of view for future conservation and for analytical and historical artistic studies.

The chemical investigation of modern art materials and synthetic paint materials has been a major focus of research in cultural heritage science over the past decade. Since the 1970s, street art has become an influential cultural movement with significant artistic and social impact in modern cities, and the conservation of relevant artworks related to urban neo-muralism has been increasingly recognized. Understanding these materials is critical to developing conservation strategies, as their composition continues to change with industrial innovation and regulatory changes. This study presents the application of an analytical approach that integrates chemical mapping based on spectroscopic approaches together with analytical pyrolysis, chromatography, and mass spectrometry to investigate two key case studies and provide insights into the evolution of street art materials over the past 30 years. This comprehensive approach provides a deeper understanding of the composition and transformation of urban art materials over time, overcoming the limitations of individual methods and revealing both organic and inorganic materials. This combined approach represents the state of the art in the study of synthetic paints used in modern art and provides new insights into the evolution of the formulation of materials used by street artists.

The unicellular microalga Euglena gracilis has always been considered the ideal alga to investigate photoreceptive responses and systems, and it has been the subject of hundreds of articles. Moreover, because of its detectable photoreceptor, it has been given a key role in the evolution of photoreception, from single and simple cells to complex visual system of higher organisms. In this article, we report the Raman spectra recorded in vivo on photoreceptors of E. gracilis and Bos taurus retina. The almost perfect superimposability (correlation coefficient r = 0.955) of these spectra states that the Euglena possesses a photoreceptor with the same structural characteristic of a vertebrate photoreceptor, i.e. a stack of membrane layers embedding rhodopsin‐like proteins. Raman spectra recorded in vivo on photoreceptors of E. gracilis after hydroxylamine treatment further confirm our findings, which should lead to a reconsideration of most of the scientific literature on algae photoreception and eye evolution.

Gems, especially from remote areas, were highly demanded and valued in Byzantine times, often used for sacred Imperial purposes. Because of their imperishable nature, they were often re-used over time and many of them passed, one way or another, from East to Western Europe. The history of the gems set in Byzantine relics that survived in medieval Europe is often impossible to reconstruct. The exceptional opening of the relics of St. John the Baptist in Siena, 200 years after the last inspection, has made it possible to study the magnificent gems that adorn it. Spinels, rubies, sapphires and other gems from oriental geographies, along with high quality glasses used together regardless of their monetary value, were identified in the relic and its reliquary case through gemological analysis and portable Raman spectroscopy, once again demonstrating the vital contribution of the trans-disciplinary approach in the study of ancient art goldworkings. (c) 2024 The Author(s). Published by Elsevier Masson SAS on behalf of Consiglio Nazionale delle Ricerche (CNR). This is an open access article under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ )

In this paper, we will discuss a new method for obtaining information about the plasma temporal evolution in Laser-Induced Breakdown Spectroscopy (LIBS) experiments using a time-integrated spectrometer.The method, inspired to the Bredice 3D-Boltzmann plot formalism, allows a precise determination of the temporal evolution of the emission line intensity in a LIBS plasma, starting from a series of time-integrated measurements obtained at different delay times after the laser pulse.In this way the application of a calibration-free algorithm using a time-integrated spectrometer is made possible.Examples of the application of the method are given in the analysis of two Zamac (a zinc alloy containing aluminum, magnesium, and copper) certified samples. A good agreement is obtained between the calculated and nominal concentrations of the two samples.A further validation of the method was performed on a third Zamac sample, of unknown composition. The sample was first characterized using a conventional CF-LIBS approach on a time-resolved spectrum; the obtained composition was then compared with the one determined using the series of time-integrated spectra.

Liquid suspensions of phosphorene nanolayers (2D-bP) obtained through liquid phase exfoliation (LPE) of elemental black phosphorus (bP) have been prepared and extensively characterized. The exfoliating ability of deionized water (DI water), dihydrolevoglucosenone, (Cyrene), and N-methyl-2-pyrrolidone (NMP) has been investigated and compared along with the differences in the structure, concentration, and stability of the collected nanoflakes. Water was chosen as an exfoliating medium due to its harmlessness and cost-effectiveness and because it is the safest solvent for further potential biomedical applications. Cyrene is a new bio-based solvent still under study. NMP, which is among the most widely used solvents for the exfoliation of 2D systems including bP, has been employed for comparison. The obtained suspensions have been characterized by Dynamic Light Scattering (DLS), Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES), Phosphorus 31 Nuclear Magnetic Resonance (31P NMR), Transmission Electron Microscopy (TEM), Ultraviolet (UV)-Visible (Vis) (UV–Vis), and Raman spectroscopies. The stability of 2D-bP suspensions over time and their photoactivity, i.e., their ability to generate singlet oxygen species as a photosensitizer, have been investigated. The collected results evidenced that the exfoliation of bP in different solvents, including DI water, resulted in satisfactory and comparable nanoflake structures and features. The singlet oxygen generation through irradiation of 2D-bP in DI water suspensions, advantageously obtained directly from LPE, showed promising potential for use in photodynamic therapy (PDT). Preliminary data on the potential biomedical application of 2D-bP to inhibit the insulin self-assembly into amyloid aggregates as well as to cause fibrils disassembling through simple incubation or photoactivity, are also discussed.

Several samples coming from the recently discovered (February 2019) Late Bronze Age/Early Iron Age Chovdar necropolis in Azerbaijan were analysed using the X-ray fluorescence (XRF) technique. The analysis allowed a preliminary classification of the samples in eight groups based on their composition, obtained from the XRF spectra using the fundamental parameter method. A more detailed classification was then obtained using the graph clustering method.

• The Single-Sample Calibration LIBS (SSC-LIBS), proposed on this journal by Rui Yuan et al., in 2019, is discussed. • We show that non-declared assumptions make the method equivalent to a conventional calibration curve approach. • As a consequence, the method cannot provide better analytical results than the ones obtained from a normal calibration curve.

The objectives of this paper will be to discuss the issues related to the determination of the limits of detection (LOD) in laser-induced breakdown spectroscopy (LIBS) analytical applications. The derivation of the commonly used '3-sigma over slope' rule and its evolution towards the new official definition recently adopted by the International Union of Pure and Applied Chemistry (IUPAC) will be illustrated. Methods for extending the calculation of the LOD to LIBS multivariate analysis will also be discussed, using as an example the detection of Cu traces in cast iron samples by LIBS.

This review paper will present and critically discuss the evolution of the calibration-free LIBS (CF-LIBS) method and some of its new applications that appeared since the last extensive review on the topic, which was published more than 10 years ago.