Search Results (692)

Germination is widely recognized as an effective strategy to enhance the nutritional quality and reduce anti-nutritional factors in plant foods. This study evaluated the impact of germination on Cruciferous vegetables (family Cruciferae or Brassicaceae) broccoli and kale by assessing changes in proximate composition, macro- and microelement profiles, total and individual polyphenols, phytic acid content, antimicrobial activity, and structural characteristics using Fourier Transform Infrared Spectroscopy (FTIR) and Small- and Wide-Angle X-ray Scattering (SAXS/WAXS) analyses. Germination significantly increased protein content (30.33% in broccoli sprouts and 30.21% in kale sprouts), total phenolic content (424.40 mg/100 g in broccoli sprouts and 497.94 mg/100 g in kale sprouts), and essential minerals, while reducing phytic acid levels in both species (up to 82.20%). Antimicrobial effects were matrix-dependent, being detected in broccoli and kale seed powders, while no inhibitory activity was observed for the corresponding sprout powders under the tested conditions. FTIR spectra indicated notable modifications in functional groups related to carbohydrates, proteins, and phenolic compounds, while SAXS analysis revealed structural reorganizations at the nanoscale. Overall, germination improved the nutritional and phytochemical quality of broccoli and kale while decreasing anti-nutritional compounds, highlighting its potential to enhance the health-promoting value of Brassica sprouts. Full article

Black crust and spalling are common deterioration phenomena affecting marble relics, yet their correlation remains inadequately understood. Hyperspectral imaging, reflectance spectroscopy, portable X-ray Fluorescence (p-XRF), infrared thermography, Scanning Electron Microscopy coupled with Energy-Dispersive Spectroscopy (SEM-EDS), and microbiological analysis was employed to connect these two types of deterioration on the Danbi stone carving of the Confucian Temple in Beijing. Spectral and thermal analyses reveal that black crust significantly reduces reflectance and increase solar absorption by 27%, resulting in thermal stress. p-XRF and SEM-EDS analyses indicated that black crust is enriched in Fe, Ti, Zn, Pb, As and clay minerals, while spalling areas display increase Ca, reflecting substrate exposure. Microscopy reveals microcracks at the layer–substrate interface. Microbiological analyses identify Cladosporium anthropophilum and Alternaria alternata as contributors to surface-darkening. These multi-scale datasets collectively demonstrate that alterations in surface chemistry and bio-mediated darkening promoting the formation of black crusts, which subsequently induce marble spalling due to solar absorption and thermal stress. These findings clarify the coupled physical–chemical–biological pathways through which black crust accelerates stone spalling. Full article

The Sar-e-Sang lapis lazuli deposit has a mining history exceeding 5000 years, producing the world’s finest lapis lazuli. Recently, gem-quality forsterite has been discovered in the marble containing spinel, dolomite, and phlogopite at the periphery of the lapis lazuli ore body at the Pitawak mine, located east of the Sar-e-Sang deposit. The mineral assemblage indicates that the protolith of this marble is dolomite with aluminous and siliceous components. These forsterite crystals occur as colorless, transparent anhedral grains, exhibiting distinct red fluorescence under 365 nm ultraviolet light. To investigate the gemological and spectroscopic characteristics of the Pitawak mine forsterite, this study conducted and analyzed data from basic gemological analysis, electron probe microanalysis (EPMA), Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), ultraviolet–visible absorption spectroscopy (UV-VIS), Fourier-transform infrared spectroscopy (FTIR), laser Raman spectroscopy (RAMAN), and photoluminescence spectroscopy (PL) on four forsterite samples from the Pitawak mine. The analysis results reveal that the samples indicate a composition close to ideal forsterite with a crystal chemical formula of (Mg_2.00Fe_0.02)_Σ2.02Si_0.99O₄. The trace elements present include Fe, Mn, Ca, and minor amounts of Cr and Ni. The UV-VIS spectroscopy results show that the samples possess high transmittance across the visible light range with very weak absorption bands, contributing to the colorless and transparent appearance of Pitawak mine forsterite. This phenomenon is attributed to the extremely low content of chromophoric elements, which have a negligible effect on the forsterite’s color. PL spectroscopy indicates that the red fluorescence of the samples is caused by an emission peak near 642 nm. This emission peak arises from the spin-forbidden ⁴T₁ → ⁶A₁ transition of Mn²⁺ ions situated in octahedral sites within the forsterite structure. Full article

Rapid and reliable analytical methods are required to support quality control and decision-making in lithium-bearing mineral processing. In this study, the application of Fourier Transform Infrared (FTIR) spectroscopy combined with Partial Least Squares (PLS) chemometric modeling is evaluated for the simultaneous prediction of lithium oxide (Li₂O) and spodumene contents in pegmatitic samples. Two independent PLS models were developed using FTIR spectra preprocessed with first derivative and/or Standard Normal Variate (SNV). Spectral regions were selected based on the vibrational response of Al–O, Si–O, and OH⁻ groups, which are indirectly influenced by lithium-bearing phases. The spectral datasets were divided into calibration and independent external test sets, and model performance was assessed using statistical metrics and Principal Component Analysis (PCA). The Li₂O model achieved an R² of 0.9934 and an RMSEP of 0.185 in external validation, with a mean absolute error below 0.15%. The spodumene model achieved an R² of 0.9961, an RMSEP of 1.79, and a mean absolute error of 2.80%. These results demonstrate that the FTIR-PLS approach enables efficient quantitative estimation of lithium-bearing minerals, with reduced analytical time, good predictive accuracy, and suitability for application in process control and mineralogical sorting environments. PCA confirmed the statistical representativeness of the test sets, with no evidence of spectral extrapolation. Full article

Urban pollution—especially SO₂ and particulate matter—rapidly darkens and degrades outdoor-exposed wall paintings due to soiling. Laser cleaning has emerged as a cutting-edge solution, offering selective removal of contaminant layers while preserving the integrity of the underlying materials. This study explores the performance of a 355 nm Nd:YAG laser in cleaning artificially aged paint mock-ups coated with real diesel soot and exposed to an accelerated aging test with SO₂ exposure. Traditional mineral pigments—silicates (Egyptian blue, ultramarine blue, and green earth), oxides (chromium green, mars red), and a sulphide (cinnabar)—were applied following fresco and secco (egg yolk) techniques, allowing researchers to uncover how pigment chemistry and binders affect laser sensitivity. Damage thresholds were first determined for each pigment and painting technique via digital photography, stereomicroscopy, and colour spectrophotometry. Cleaning efficacy was then assessed by stereomicroscopy, colour spectrophotometry, Fourier-transform infrared spectroscopy, and scanning electron microscopy. The results revealed clear patterns: silicate pigments exhibit stability under laser irradiation, enabling safe cleaning, whereas mars red and cinnabar remain highly sensitive regardless of the technique. Generally, secco paintings were more susceptible to laser radiation than fresco. These finding provide practical guidance for optimising laser-cleaning protocols while safeguarding the delicate surfaces of historic wall paintings. Full article

Through this work, an experimental setup and pre-processing method for obtaining fluorescence and quasi-noise-free Raman spectra of minerals for in situ mineral identification in an underground environment is proposed. It uses a combination of methodologies like dual excitation wavelengths, Shifted Excitation Raman Difference Spectroscopy (SERDS), and deep learning-based U-Net model for background and noise correction. The dual excitation wavelengths technique employs a near-infrared SERDS laser for the fingerprint and a red laser for the large Raman shift region. The SERDS laser operates at two excitation wavelengths and is tuneable in the vicinity of 785 nm. The red laser uses 671 nm excitation wavelength. The obtained fingerprint and large Raman shift Raman spectra are then fed to a pre-processing method containing the trained U-Net model for obtaining a background-corrected and quasi-noise-free Raman spectrum. The proposed method addresses issues of existing handheld Raman systems in terms of spectrometer sensitivity, spectrum acquisition speed, pre-processing time, fluorescence effects, and other interferences due to surrounding light or vibration. The obtained final processed Raman spectrum is then deconstructed into pseudo-Voigt peaks. The identification of the minerals can be based on the number and the positions of the pseudo-Voigt peaks. Samples of gypsum (CaSO₄·2H₂O) and anhydrite (CaSO₄) were used for evaluating the performance of the proposed method. The influence of measurement time on the reproducibility and precision of the peak identification and, thus, mineral identification is also analyzed. Full article

This study introduces a controlled laboratory setup for hyperspectral longwave infrared (LWIR) imaging of soils, designed to bridge the gap between laboratory measurements and remote sensing observations. A Fourier-transform hyperspectral LWIR imaging spectrometer (Telops Hyper-Cam LW) was employed, together with a specialized heating plate, rigorous calibration protocols, and a Spatial Averaging Before Blackbody Fitting (SABBF) method to enable accurate LWIR indoor measurements. Unlike established laboratory techniques that measure reflectance and calculate emissivity indirectly, this setup enables direct passive measurement of soil emissivity, replicating airborne and spaceborne LWIR measurements of the surface. The emissivity spectra of 12 variable soil samples obtained with the lab setup were compared and validated based on LWIR Hyper-Cam LW spectra acquired under outdoor conditions, then were subsequently analyzed to determine the mineral composition of each sample. Spectral features and indices were used to estimate the relative content of quartz, clay minerals, and carbonates, from the most to least abundant. The results demonstrate that the laboratory-based setup preserves spectral fidelity while offering improved repeatability, scheduling flexibility, and reduced dependence on weather. Beyond replicating outdoor measurements, this controlled setup is easy to install and provides a reproducible framework for LWIR soil spectroscopy that could be considered for standard laboratory protocols, enabling reliable mineral identification, calibration/validation of airborne and satellite LWIR data, and broader applications in soil monitoring and environmental remote sensing. Full article

Nickel ions (Ni²⁺) are persistent heavy metal pollutants that pose significant risks to human health due to their toxicity. Conventional treatment technologies, while effective, are often costly, energy-intensive, and limited in removing emerging pollutants. In this study, we report an eco-friendly, fluorescence-based sensing platform using carbon nanostructures (CNs) synthesized from coffee waste via pyrolysis at 600 °C. The CNs were characterized by Fourier transform infrared (FTIR) spectroscopy and evaluated for their fluorescence response toward Ni²⁺, Co²⁺, Cu²⁺, and Cd²⁺ ions. Distinct ion-specific behaviors were observed, with Ni²⁺ inducing the strongest fluorescence quenching. Sensitivity studies revealed reliable detection across 10⁻⁸–10⁻³ M, with a detection limit of 10⁻⁴ M (≈5.9 mg/L). Fluorescence stability was maintained for up to six hours, with one hour identified as the optimal detection window. Performance in real water samples highlighted consistent responses in mineral water, reflecting reliable sensing capability in a realistic aqueous matrix. While the current detection limit is above the World Health Organization guideline for drinking water, the CNs show promise for monitoring Ni²⁺ in contaminated or industrial effluents. Overall, this work demonstrates that coffee waste-derived CNs provide a cost-effective, sustainable approach to heavy metal sensing, linking waste valorization with environmental monitoring. Full article

Hubei Province is a significant center for cultural and trade exchange in Central China. However, since no nephrite deposit has been discovered in Hubei, nephrite artifacts excavated within its jurisdiction must have been obtained from other regions. Tracing their provenance can contribute to our understanding of the trade exchange between ancient Hubei and other regions. In this study, the appearance, spectroscopy, and chemical compositions of nephrite artifacts excavated from the Fangjiagang Cemetery of the Eastern Zhou Dynasty, Hubei Province, were systematically studied, and their provenance was discussed. The characteristics of a weathered layer of raw nephrite material retained in one of the jade artifacts (M22:5) indicate it should be made from the placer nephrite of Hetian, Xinjiang. Infrared and Raman spectroscopy confirms that both the whitened and unwhitened areas in the samples are composed of tremolite, indicating that the whitening mechanism should be attributed to the etched structures caused by weathering rather than a change in the major mineral composition caused by high temperature. When no obvious appearance-based characteristics remain, chemical compositions become a crucial tool for discussing the provenance of jade artifacts. The chondrite-normalized rare earth element patterns for the samples suggest that their formation is associated with granite intrusion, implying that the placer nephrite of Hetian, Xinjiang; Xiuyan nephrite, Liaoning; Golmud nephrite, Qinghai; Xiaomeiling nephrite, Jiangsu; Vitim nephrite, Russia; and Chuncheon nephrite, South Korea, are potential sources. However, the trace element spider diagrams for the samples show a better match with those of the placer nephrite of Hetian. The placer nephrite of Hetian was used in Fangjiagang Cemetery, indicating that the trade exchange between the Eastern Zhou dynasty and the Hetian area had already been established. Full article

In response to the increasing consumer demand for healthier diets and the needs of individuals with gluten intolerance, chestnut flour (CF) emerges as a valuable unconventional ingredient for sustainable and functional nutrition. This study evaluated the nutritional, phytochemical, and functional properties of gluten-free biscuits formulated with whole rice flour (RF), CF, and their mixtures, where RF was replaced by CF at 0% (control), 10%, 30%, 70%, 90%, and 100% (w/w). In addition, in the 50% CF formulation, 5% of RF was substituted with fruit powders rich in phenolic compounds and recognized as fortifying agents, such as chokeberry (CP), açaí (AP), and blueberry (BP). Proximate composition, macro- and microelement content, total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activity (DPPH and FRAP assays) were determined for the individual flours, composite flours, fruit powders, and biscuit formulations. Structural characteristics were assessed using Small- and Wide-Angle X-ray Scattering (SAXS/WAXS) analysis and Fourier Transform Infrared Spectroscopy (FTIR). Results showed that CF incorporation enhanced both the nutritional and functional profile of flours and biscuits, increasing protein, fiber, lipid, and mineral contents while reducing carbohydrates, and improving TPC, TFC, DPPH, and FRAP values. Fortification with 5% CP, AP, or BP further boosted the phytochemical content of the biscuits, with the chokeberry-enriched sample exhibiting the highest TPC (348.88 mg GAE/100 g d.s.), TFC (253.82 mg QE/100 g d.s.), DPPH (50.36%), and FRAP (21.07 μM Fe²⁺/g d.s.). The combination of 50% CF and 5% CP provided dual benefits, significant bioactive enrichment alongside the preservation of desirable technological properties. Complementary SAXS/WAXS and FTIR analyses indicated that CF and fruit powders enhanced molecular interactions and matrix cohesion, which may contribute to improved texture and antioxidant potential of the biscuits. Overall, this formulation offers a promising and practical approach to developing functional gluten-free biscuits with enhanced nutritional, phytochemical, functional, and structural characteristics. Full article

The study and preservation of illuminated manuscripts, particularly miniatures on parchment, are crucial for understanding the artistic, cultural, and technological history of the past. This research investigates the materials used in a 16th-century illuminated scroll, analyzing both the miniatures and the written text through non-invasive techniques. A multi-analytical approach was applied, including optical microscopy, Hypercolorimetric Multispectral Imaging (HMI), infrared reflectography in the 950–1700 nm range, Fiber Optics Reflectance Spectroscopy (FORS), macro X-ray fluorescence (MA-XRF) spectroscopy, Raman spectroscopy, and External Reflection Fourier Transform Infrared (ER-FTIR) spectroscopy. These methods provided a comprehensive characterization of the painting materials’ chemical composition and the artistic techniques utilized, revealing new information on Renaissance materials and practices. The detected mineral pigments primarily include smalt, vermilion, lead white, and minium, which are consistent with materials commonly found in illuminated manuscripts. Aluminosilicate and calcite were identified as fillers or substrates utilized for organic dyes, particularly those generating pink hues. An uncommon finding was the green pigment, which was identified as copper hydroxynitrate. Furthermore, gold and silver were extensively employed in the decorative elements, both as metal foils and in shell pigment form. Finally, the capital letters were executed using smalt and vermilion, while the black text ink was characterized as iron gall ink, a composition typically employed on parchment supports. Full article

Quartz and feldspar have similar physical, chemical, and surface properties. Effectively separating them in near-neutral systems has long been a challenging research focus. This study introduces 1-Dodecyl-3-methylimidazolium bromide (DMB), an ionic liquid, as a collector in a quartz–feldspar flotation separation system to investigate its effects on the flotation behavior of quartz and feldspar. The interaction between the collector and the minerals is explained through zeta potential measurements, infrared spectroscopy analysis, and DFT calculations. The flotation test results indicate that DMB exhibits selective flotation separation properties enabling the separation of quartz from feldspar. Across the pH range of 3 to 11, DMB demonstrates high collection capability for quartz, but lower capability for feldspar. In particular, at pH levels of 7 to 8, the recovery difference between the two minerals exceeds 80%, achieving optimal selective separation. Mechanistic studies indicate that DMB primarily adsorbs on quartz and feldspar through electrostatic adsorption. The adsorption energy between DMB and quartz reaches −340.59 kJ/mol, forming a stable adsorption layer on the quartz surface. However, electrostatic repulsion arises over a broad area due to the large volume and cationic nature of DMB’s polar group and the exposed cationic Al sites on the feldspar surface, thereby hindering the interaction between DMB and feldspar. This research establishes the foundation for achieving efficient selective flotation separation of quartz and feldspar in a neutral system. Full article

Molybdenite and chalcopyrite closely coexist and have good natural floatability. During the Cu-Mo separation process, it is necessary to enhance the inhibition of chalcopyrite to reduce its influence on molybdenite. In this paper, a combined inhibitor, sodium thioglycollate (HSCH₂COONa) and sodium sulfide (Na₂S), with a molar ratio of 2:1, was obtained through pure mineral flotation experiments. It could reduce the impact on molybdenite while maintaining a good inhibitory effect on chalcopyrite. In the artificial mixed minerals test, the use of the combined inhibitor (80 mg/L) can achieve good indicators with Mo grade and recovery rate of 54.34% and 88.12%, respectively, and Cu grade of 2.15%. The contact angle test shows that the combined inhibitor can significantly reduce the wettability of the chalcopyrite surface while having a relatively small effect on molybdenite. The infrared spectroscopy and SEM-EDS energy spectrum indicated that the combined inhibitor C = O and S-H groups underwent chemical reactions on the surface of chalcopyrite and squeezed out kerosene on the surface of chalcopyrite. Molecular dynamics simulations indicate that the HS⁻, S²⁻, and HSCH₂COO⁻ components in the combined inhibitor are more likely to act on the surface of chalcopyrite, exerting an enhanced inhibitory effect on chalcopyrite. Full article

Maw-sit-sit jade resembles kosmochlor-jadeitite in appearance and is spatially associated with it in the Myanmar Jade Belt. However, the mineral composition, microstructure, and petrogenesis of this type of jade remain unclear. To address this gap, this study investigated high-quality Maw-sit-sit jade using a range of analytical techniques, including conventional gemological tests, infrared spectroscopy, petrographic observations, electron probe microanalysis (EPMA), and backscattered electron (BSE) imaging. Results show that Maw-sit-sit jade primarily consists of albite and chromium-omphacite, with minor amphibole (eckermannite and richterite). Jadeite and relict chromite are absent in the studied samples. Its high albite content gives it lower refractive index (RI: 1.55–1.56) and specific gravity (SG: 2.69–2.73) compared to kosmochlor-jadeitite and jadeite jade. Additionally, Maw-sit-sit jade exhibits punctate or banded fluorescence under ultraviolet (UV) light, distinguishing it from kosmochlor-jadeitite and jadeite jade (both inert). Petrographically, euhedral albite fills interstices between early-formed Cr-omphacite and eckermannite, which is textural evidence of its late-stage origin. Eckermannite and Cr-omphacite occur as enclosed grains with embayed boundaries and dissolution pores, indicating they experienced mechanical disruption and chemical dissolution during subsequent geological processes. Petrogenetically, Maw-sit-sit jade (defined as “Cr-omphacite-albitite”) forms via a two-stage process: (1) Under high-pressure/low-temperature (HP/LT) conditions in the subduction zone, Na-Al-Si-rich fluids metasomatize chromite-bearing serpentinite protoliths, generating an early assemblage of jadeite, Cr-omphacite and amphiboles; (2) During subsequent plate exhumation and decompression, jadeite underwent retrograde metamorphism under low-pressure/low-temperature (LP/LT) conditions involving residual Na-Al-Si fluids, resulting in the formation of albite. This process led to the replacement of early-formed minerals by euhedral albite, ultimately generating the Ab+Cr-Omp+Eck symplectic texture. This study elucidates the mineralogical, gemological identity and petrogenesis of high-quality Maw-sit-sit jade, advancing our understanding of fluid evolution within a subduction zone. Full article

A recently discovered turquoise deposit in the Fangshankou area of Dunhuang, Gansu Province, has been relatively understudied compared to turquoise from other sources due to its short mining history. Currently, no relevant research literature on this deposit has been identified. Therefore, a systematic mineralogical and spectroscopic study of Dunhuang turquoise samples was conducted using conventional gemological testing methods, combined with techniques such as X-ray powder diffraction (XRD), electron probe microanalysis (EPMA), Fourier transform infrared spectroscopy (FTIR), laser Raman spectroscopy, ultraviolet-visible spectroscopy (UV-Vis), and X-ray fluorescence (XRF) mapping. The test results indicate that the turquoise samples from this area have a density ranging from 2.40 to 2.77 g/cm³ and a refractive index between 1.59 and 1.65. The samples generally exhibit a cryptocrystalline structure, with some displaying spherulitic radial and radial fibrous structures. The texture is relatively dense and hard, with particle diameters less than 10 μm. Chemically, the turquoise samples from this region are characterized by high Fe and Si content and relatively low Cu content. Samples contain, in addition to the turquoise mineral, other minerals such as quartz, goethite and alunite, etc. The oxide content ranges are as follows: w(P₂O₅) between 23.83% and 33.66%, w(Al₂O₃) between 26.47% and 33.36%, w(CuO) between 5.26% and 7.91%, w(FeO) between 2.46% and 4.11%, and w(SiO₂) between 0.97% and 10.75%. In the infrared absorption spectra of Dunhuang turquoise, the bands at 3510 cm⁻¹ and 3464 cm⁻¹ are attributed to ν(OH)⁻ stretching vibrations, while the bands near 3308 cm⁻¹ and 3098 cm⁻¹ are assigned to ν(M-H₂O) stretching vibrations. The infrared absorption bands near 1110 cm⁻¹ and 1058 cm⁻¹ are due to v[PO₄]³⁻ stretching vibrations, and the bands near 651 cm⁻¹, 575 cm⁻¹, and 485 cm⁻¹ are attributed to δ[PO₄]³⁻ bending vibrations. A clear correlation exists between the Raman spectral features and the infrared spectra of this turquoise. The hue and chroma of the turquoise from this area are primarily influenced by the mass fractions of Fe³⁺, Cu²⁺, and Fe²⁺, as well as their bonding modes with water molecules. The ultraviolet-visible spectra are attributed to O²⁻–Fe³⁺ charge transfer, the ⁶A₁–⁴E_g + ⁴A₁ transition of Fe³⁺ ions (D⁵ configuration) in hydrated iron ions [Fe(H₂O)₆]³⁺, and the spin-allowed ²E_g–²T_2g transition of Cu²⁺ ions in hydrated copper ions [Cu(H₂O)₄]²⁺. Associated minerals include goethite, alunite, jarosite, and quartz. Fine-grained quartz often exists as secondary micron-sized independent mineral phases, which have a certain impact on the quality of the turquoise. Full article