This work investigates the composition of the patina and state of preservation of an Etruscan bronze fibula from Tomb 129 of Vulci Archaeological Park (VT, Italy), dating back between the late eighth and early seventh centuries BC. Non-destructive analytical techniques, such as micro-Raman spectroscopy and energy-dispersive X-ray fluorescence (ED-XRF) combined with Monte Carlo simulations, were used to analyze the patina's mineralogy and the alloy's chemical composition. Monte Carlo simulation was applied to model the layered structure of the fibula accurately and distinguish between the alloy and the patina, allowing the elemental composition of the fibula to be known and excluding selective depletion phenomena. Innovative 3D reconstruction through X-ray microscopy (XRM) allowed the characterization of the internal structure of the artifact and its state of preservation. Micro-Raman results on the patina identified the occurrence of brochantite and sampleite due to interactions with the burial environment and the decomposition of organic matter. The fibula was a binary bronze alloy (Cu-Sn) with a low tin content and minimal lead concentration. XRM analysis detected fragility points and a small blind hole inside the fibula, probably related to the manufacturing processes. These findings provide insight into the artifact's conservation status and contribute to a better understanding of ancient Etruscan metalworking techniques. By integrating advanced analytical methods and non-invasive imaging, this study highlights the potential of combining scientific techniques to preserve cultural heritage and deepen our knowledge of metallurgical practices in ancient civilizations.
Over the last decade, Raman spectroscopy has established itself as a fundamental technique for planetary exploration and the geological characterization of bodies in our Solar System. ESA has been evaluating combinations of analytical methods combined in a portable, handheld analytical tool for planetary surface exploration missions, with the potential use-case being human missions to the surface of the Moon (e.g., in the frame of the NASA-led Artemis program). Based on the Raman technique, we report on a development that seeks to complement Raman with other techniques for determining chemical composition, such as LIBS or XRF, and also provided with a close-up imager integrated into the instruments to obtain context images of the analyzed samples, to determine their texture and help select the point of analysis. For this design, portability and ergonomic considerations are also being taken into account, since they must be operated by future astronauts quickly and efficiently. Breadboard instruments developed in the frame of an ESA contract are designed to interface wirelessly with an electronic field book and are usable not just in a laboratory environment but also as training equipment on Earth during the analogue field campaigns of its astronauts within the PANGAEA program. This work shows the performance obtained by one of the two Portable Handheld cOmbinEd RamaN-LIBS-XRF (PHOENIX) instruments developed within the framework of this ESA contract.
The article presents the results of a combined experimental and computational study by DFT methods of Raman and Mössbauer spectra, dynamical and nonlinear optical (NLO) properties of single-component and multicomponent garnets Y3Fe5O12 (YIG), LnIG (Ln = Eu, Gd, Dy, Er), and (Y0.2Gd0.2Er0.2Eu0.2Dy0.2)IG (YLnIG), synthesized by glycine–nitrate pyrolysis. The Raman band assignments to fundamental vibrational modes were held using an analysis of experimental data with the support of phonon spectra ab initio calculations. It was shown that displacements of all atoms except Fe in octahedra are involved in Raman active vibrational modes. The most intensive Raman bands are attributed to phonon modes related to atomic displacements in FeO4 tetrahedra. Raman spectra measurements performed for YIG and YLnIG garnets in the temperature and pressure ranges of 83–773 K and 0–13 GPa revealed their structural stability with the absence of any phase transition fingerprints. The analysis of temperature and baric behavior of vibrational modes disclose that the value of anharmonicity in multicomponent garnet YLnIG is of the same magnitude as the one in single-component YIG. The values of thermal expansion coefficients were estimated to be equal to 11.07·10−6 and 10.20·10−6 K−1 for YLnIG and YIG garnets respectively. The nonlinear properties of YIG and EuIG garnets were studied theoretically using the CPHF approach; the values of nonzero susceptibility tensor components were characterized by high values of diagonal components: the values were equivalent to = 35.8·10−22 and 38.4·10−22 m2/V2 and = 9.04·10−22 and 9.10·10−22 m2/V2, respectively, for YIG and EuIG.
This study evaluates the potential of surface-enhanced Raman spectroscopy (SERS) as a rapid and sensitive diagnostic tool for myasthenia gravis (MG). Blood serum from 120 participants, including patients with MG, thymoma-associated MG (T-MG), and a control group, was analyzed. Using substrates with implanted gold nanoparticles (5–6 nm), we identified specific spectral features distinguishing MG patients from healthy individuals. SERS spectral analysis revealed nitro-group vibrational modes at 798 and 1336 cm−1, absent in the control cohort. These peaks, associated with oxidative stress and protein nitration, form a potential biochemical signature of MG pathophysiology. Spectral characteristics remained stable regardless of patient sex or serum storage duration, confirming the method's reliability. Reproducibility of the enhanced signal was ensured through Fröhlich frequency optimization for stable plasmon resonance, as well as a controlled medium filling factor, stable nanoparticle coordinates, and molecular localization in dried serum droplets. These findings establish SERS as a promising tool for MG biomarker identification, providing a reproducible and sensitive method for differential diagnosis through stable signal enhancement. Moreover, this approach paves the way for expanding SERS applications in studying oxidative stress levels across various pathological conditions.
Emeralds frequently contain inclusions, and their study can provide valuable clues on their geological origin. For the present study, 11 emeralds containing elongated amphibole inclusions from four geographic origins (three from Austria, one from Russia, two from Zambia and five from Zimbabwe) were investigated with an optical microscope and Raman spectroscopy. The inclusions have various sizes and shapes; curved inclusions are frequently observed in emeralds from Zimbabwe and in one sample from Zambia. Most inclusions are of actinolite; tremolite is observed in Austrian samples and cummingtonite in samples from Zimbabwe. These subtle differences in amphibole inclusions in emeralds could help identify emeralds from these mining regions.
This study investigated the thermal maturity of the Pendência Formation (Lower Cretaceous) in the onshore Potiguar Basin, Brazil, using vitrinite reflectance (%Ro) and Raman spectroscopy. Nine fine-grained rock samples were collected from well 6-BRSA-588-RN, and their %Ro values were compared with previously unpublished data from two nearby wells. The results indicated a consistent maturation trend, with %Ro increasing with depth, reaching values indicative of the dry gas window in the deepest parts. The %Ro profile for well 6-BRSA-588-RN is consistent with oil and gas throughout the well, confirming that the Pendência Formation is a significant source rock in this basin portion. Raman spectroscopy was used to assess the thermal maturity of organic matter qualitatively; a narrowing of the G-band width in the spectra was observed with increasing maturity, ascribed to the reorganization of carbon into a more ordered structure, corroborating the %Ro trend. The spectral profile of organic matter depends on the excitation radiation: short-wavelength lasers have proven advantageous for low-maturity samples because of the resonance Raman enhancement with smaller aromatic systems, producing stronger Raman signals that remain visible despite fluorescence interference. However, alternative long-wavelength exciting lines can be used, and this influence was proved in the Raman spectral results. The integrated analysis of %Ro and Raman data suggests lateral variations in thermal maturity within the Pendência Formation. This study contributes to the limited database of the Potiguar Basin. It highlights the potential of Raman spectroscopy as a complementary tool for assessing source rock maturity, paving the way for a more comprehensive understanding of the basin's petroleum systems and their exploration.
Biomimetic designs are inspired by the complex and unique behavior of naturally occurring materials, and can be applied to many systems, including polymers. ZIPer polymers (Zwitter arene-ion like polymer) are inspired by byssal threads found on mussels, and their physical state is highly sensitive to various environmental conditions. Specifically, the ZIPer polymer undergoes chemospecific phase transitions, exhibiting potential for its use as an ionic responsive technology. Though this phenomenon has been observed with Raman spectroscopy, little is known about how salt identity or concentration affect polymer inter- and intra-chain interactions. Previous studies have used Raman spectroscopy to analyze ZIPer polymer behavior in the presence of salt; however, the effect is typically only observed with sodium chloride and often only compares spectra at two concentrations. Additionally, studies have mainly focused on the spectral evidence of cation–π interactions, significantly narrowing their spectral range. In order to develop a more predictive framework for ZIPer polymer behavior, a range of salt identities and concentrations need to be tested. This study uses Raman spectroscopy to investigate ZIPer polymer behavior in the presence of a series of salts, namely NaCl, NaOTFA, NaBr, NaBF4, and NaPF6, each at 0.1 M, 0.5 M, 1.0 M, and 1.5 M concentrations. Moreover, we observe spectral changes in a range from 550 to 2000 cm−1. Spectral evidence suggests that the cation–π interactions previously hypothesized to be the driver of ZIPer polymer behavior are not the only mechanism determining the chemoresponsive phase transitions. We hypothesize that cation–π interactions and dispersion forces are competing mechanisms controlling ZIPer polymer behavior. Furthermore, we suggest that at certain concentrations the dominating mechanism transitions, and this inflection point is salt identity dependent.
We carried out a detailed study of the texture, mineralogy, and spectroscopic properties of the Slobodka ordinary chondrite meteorite. Previous descriptions differ on the classification of this meteorite, so we re-evaluated its petrologic type and shock stage. The observed texture and mineral chemistry are most consistent with the L4 chondrites. It records features of strong shock metamorphism mostly consistent with shock stage S4, including irregular and planar fractures, undulatory extinction, and mosaicism in olivine, pyroxene, and plagioclase. The distribution of shock damage was further evaluated at the mesoscale, revealing significant heterogeneity: regions of shock stage S4 are located near shock melt veins, a few selected areas indicate shock stage S3, and areas farther away from shock melt veins exhibit shock stage S2. The application of a range of in-situ analytical techniques, including Raman spectroscopy and electron back-scatter diffraction as well as microprobe, revealed the presence of five preserved high-pressure phases within the investigated sample of Slobodka, namely albitic jadeite, tuite, majorite, wadsleyite, and xieite. Together, these findings demonstrate that Slobodka preserves textural and mineralogical characteristics indicative of the highly energetic impact that likely fragmented the parent body of the L-chondrites.
The formation of amyloid fibrils by different proteins and peptides is a well-studied topic. In the last decade, it has been reported that metabolites can also self-assemble into amyloid-like fibrils. The aggregation of single amino acids such as phenylalanine, tyrosine, and tryptophan has also been linked to tyrosinemia type II, hypertryptophanemia, and Hartnup diseases. It is a challenge to monitor the intermolecular interactions involved in the supramolecular self-assembling of metabolites in a time-dependent manner. Here, the surface-enhanced Raman scattering (SERS) technique was used to directly probe the changes in the molecular interactions during the self-assembling of tryptophan into amyloid-like structures, particularly in the initial stages. We showed that this simple and label-free nanoplasmonic-based methodology can be used to examine at the molecular level the formation of amyloid-like aggregates as a function of time. Specifically, the technique was shown to be sensitive and provide insights into the formation of hydrogen bonding, π-stacking interactions, and hydrophobicity changes during the self-assembling of tryptophan. Thus, this work can open new possibilities for the applications of SERS to describe in more detail the mechanisms of formation of other metabolites assembled structures, which may be valuable for understanding several related diseases.
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