Search Results (7,876)

Sodium chloride (NaCl) was essential for making mianpi, a traditional Chinese wheat starch gel food. The production process included wheat flour/starch slurry preparation, steaming, cooling, and cutting. This study investigated how NaCl affected both the slurry’s properties and the quality of mianpi using three formulations: wheat flour (F100), a 50:50 (w/w) wheat flour–starch mix (F50), and wheat starch (F0). Our findings demonstrated that NaCl significantly altered the slurry rheology, pasting behavior, texture, and starch ordered structures. It notably reduced the slurry apparent viscosity, while it showed a divergent effect on its pasting properties. Regarding product quality, NaCl induced a measurable alteration in L*, a*, and b* values of mianpi, though visually imperceptible. F100 mianpi maintained texture except for when adding 2% NaCl, which reduced hardness. NaCl increased tensile strength (excluding F0). However, it caused irregular texture changes in F50 and F0 mianpi. Furthermore, NaCl modulated viscoelastic properties of mianpi products, as evidenced by reductions in storage and loss modulus. FT-IR showed NaCl disrupted starch short-range order in F100/F0 but improved it in F50, though Raman spectroscopy (480 cm⁻¹) did not detect this shift. Gluten protein secondary structure remained unaffected across all formulations. These results guide NaCl–starch–flour formulations in starch-gel-based foods. Full article

Graphene, a two-dimensional carbon material with a hexagonal lattice structure, possesses remarkable properties. Exceptional electrical conductivity, mechanical strength, and high surface area that make it a powerful platform for biosensing applications. Its sp²-hybridised network facilitates efficient electron mobility and enables diverse surface functionalisation through bio-interfacing. This review highlights the core detection mechanisms in graphene-based biosensors. Optical sensing techniques, such as surface plasmon resonance (SPR) and surface-enhanced Raman scattering (SERS), benefit significantly from graphene’s strong light–matter interaction, which enhances signal sensitivity. Although graphene itself lacks intrinsic piezoelectricity, its integration with piezoelectric substrates can augment the performance of piezoelectric biosensors. In electrochemical sensing, graphene-based electrodes support rapid electron transfer, enabling fast response times across a range of techniques, including impedance spectroscopy, amperometry, and voltammetry. Graphene field-effect transistors (GFETs), which leverage graphene’s high carrier mobility, offer real-time, label-free, and highly sensitive detection of biomolecules. In addition, the review also explores multiplexed detection strategies vital for point-of-care diagnostics. Graphene’s nanoscale dimensions and tunable surface chemistry facilitate both array-based configurations and the simultaneous detection of multiple biomarkers. This adaptability makes graphene an ideal material for compact, scalable, and accurate biosensor platforms. Continued advancements in graphene biofunctionalisation, sensing modalities, and integrated multiplexing are driving the development of next-generation biosensors with superior sensitivity, selectivity, and diagnostic reliability. Full article

In view of the need to increase the durability of working tools exposed to intense friction, this study analysed hybrid coatings (TiAlCN, AlTiCN, AlCrTiN, TiN, CrN) with a DLC (Diamond-Like Carbon) layer, deposited using PVD (Physical Vapour Deposition) methods (arc evaporation and magnetron sputtering). The structural characteristics of the coatings were determined using SEM (Scanning Electron Microscope) and AFM (Atomic Force Microscope) microscopy, as well as Raman spectroscopy, which confirmed the compact structure and amorphous nature of the DLC layer. Tribological tests were performed using a ball-on-disc test, revealing that DLC hybrid coatings significantly reduce the coefficient of friction (stabilisation in the range of 0.10 to 0.14 due to DLC graphitisation), limiting tool wear even under increased load. The SEM-EDS (Scanning Electron Microscope-Energy Dispersive Spectroscopy) microscopic examination revealed that the dominant wear mechanisms are abrasive and adhesive damage, and the AlCrTiN/DLC system is characterised by low wear and high adhesion (L_c = 10⁵ N), making it the optimal configuration for the given loads. Microhardness tests showed that high hardness does not always automatically translate into increased wear resistance (e.g., the AlTiCN coating with 4220 HV showed the highest wear), while coating systems with moderate hardness (TiAlCN/DLC, CrN/DLC) achieved very low wear values (~0.17 × 10⁻⁵ mm³/Nm), which highlights the importance of synergy between the hardness of the sublayer and the low friction of DLC in the design of protective coatings. 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

Public health concerns related to food contaminants, including biotoxins, pesticide and veterinary drug residues, illegal additives, foodborne pathogens, and heavy metals, have garnered significant public attention in recent years. Consequently, there is an urgent need to develop rapid and accurate technologies to detect these harmful substances. Surface-enhanced Raman spectroscopy (SERS), due to its characteristics of high sensitivity and specificity enabling the detection of food contaminants within complex matrices, has attracted widespread interest. This review focuses on the application of noble metal-based nanocomposites as SERS-active substrates for food contaminant detection. It particularly highlights the structure–performance relationships of metallic nanomaterials, including gold and silver nanoparticles (e.g., nanospheres, nanostars, nanorods), bimetallic structures (e.g., Au@Ag core–shell), as well as metal–nonmetal composite nanomaterials such as semiconductor-based, carbon-based, and porous framework-based materials. All of which play a crucial role in achieving effective Raman signal enhancement. Furthermore, the significant applications in detecting various contaminants and distinct advantages in terms of the sensitivity and selectivity of noble metal-based nanomaterials are also discussed. Finally, this review addresses current challenges associated with SERS technology based on noble metal-based nanomaterials and proposes corresponding strategies alongside future perspectives. Full article

Background/Objectives: Within the minimum intervention oral care (MIOC) delivery framework, the management and improvement in the esthetics of enamel white spot lesions (WSLs) are recommended. This study evaluated the chemomechanical and morphological characteristics of WSLs treated by four therapeutic approaches using Raman spectroscopy, Knoop microhardness (KH), and field-emission scanning electron microscopy (FESEM). Methods: Sixty human enamel slabs were divided into six groups: non-treated (baseline), WSLs (8% methylcellulose gel with 0.1 M lactic acid, pH 4.6 at 37 °C for 21 days), and four treated groups, namely bovine collagen supplement (Nutravita Ltd., Maidenhead, Berkshire, UK), Regenerate system (NR-5, Bordeaux, France), Sylc air abrasion (AquaCare, Denfotex Research Ltd., Edinburgh, UK), and CO₂ laser (JHC1180, Jinan, China). Treatment lasted 28 days, followed by four weeks of storage in artificial saliva (pH = 7.0, 37 °C). Bovine collagen was analyzed using Fourier-Transform Infrared Spectroscopy (FTIR). The mineral content, including the phosphate peak intensities (PO₄ ν₁, ν₂, and ν₄) and carbonate (CO₃), as well as tissue microhardness, were assessed at varying depths (50–200 µm), followed by morphological assessment. Results: The FTIR spectrum of bovine collagen powder confirms the presence of amide I, II, and III. It produced a statistically significant enhancement in the phosphate content and KHN compared to WSLs of up to 150 µm in depth (p < 0.001). Regenerate-treated surfaces recorded the highest phosphate content among groups at the superficial layer. All treatment interventions enhanced the morphology of lesions by covering the exposed prisms and inter-prismatic structure. Conclusions: Bovine collagen supplements can enhance the phosphate content and surface properties of enamel white spot lesions (WSLs) and could be considered a potential modality comparable to other micro-invasive approaches for addressing incipient enamel lesions. This could significantly impact dental care management. Full article

In this study, we report the fabrication and multi-technique characterization of pure and rare-earth (RE)-doped ZnO thin films using nanostructured microclusters synthesized via electrospinning followed by calcination. Lanthanum (La), erbium (Er), and samarium (Sm) were each incorporated at five concentrations (0.1–5 at.%) into ZnO, and the resulting powders were drop-cast as thin films on glass substrates. This approach enables the transfer of pre-engineered nanoscale morphologies into the final thin-film architecture. The morphological analysis by scanning electron microscopy (SEM) revealed a predominance of spherical nanoparticles and nanorods, with distinct variations in size and aspect ratio depending on dopant type and concentration. X-ray diffraction (XRD) and Rietveld analysis confirmed the wurtzite ZnO structure with increasing evidence of secondary phase formation at high dopant levels (e.g., Er₂O₃, Sm₂O₃, and La(OH)₃). Raman spectroscopy showed peak shifts, broadening, and defect-related vibrational modes induced by RE incorporation, in agreement with the lattice strain and crystallinity variations observed in XRD. Elemental mapping (EDX) confirmed uniform dopant distribution. Optical transmittance exceeded 70% for all films, with Tauc analysis revealing slight bandgap narrowing (Eg = 2.93–2.97 eV) compared to pure ZnO. This study demonstrates that rare-earth doping via electrospun nanocluster precursors is a viable route to engineer ZnO thin films with tunable structural and optical properties. Despite current limitations in film-substrate adhesion, the method offers a promising pathway for future transparent optoelectronic, sensing, or UV detection applications, where further interface engineering could unlock their full potential. Full article

Fiber-based black-and-white developing-out papers (DOPs) were among the most widely used photographic supports of the 20th century. Their broad use, structural complexity, and range of surface finishes, alongside evolving manufacturing practices, underscore the importance of understanding their material composition for authentication, dating, and conservation purposes. This study presents a multi-analytical characterization of three DOP sample sets: two from Ilford (ca. 1950) and one from Kodak (1972), complementing previous research with a deeper insight into general features, stratigraphy, and composition. Initial non-sampling techniques, including thickness measurements, colorimetry, optical microscopy, and UV–visible induced fluorescence, were used to classify papers into visually and physically distinct groups. This informed a targeted sampling strategy for further stratigraphic and compositional analysis using Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy (SEM-EDS), X-ray fluorescence (XRF), Raman spectroscopy, and fiber/pulp identification tests. Significant differences were observed in base tint, surface gloss, optical brightening agents, fillers, and fiber content. Notable findings include the presence of iron (III) oxide–hydroxide pigment in Ilford cream papers, anatase titanium dioxide (TiO₂) in a baryta-less Ilford sample, and the shift to more uniform tones and mixed pulps in Kodak papers by the 1970s. These results offer valuable insights into historical manufacturing and support improved dating and characterization of photographic papers. Full article

In the race for industrialization and urbanization, the concentration of greenhouse gases like CO₂ and CH₄ is growing rapidly and ultimately resulting in global warming. An Ni-based catalyst over MgO support (Ni/MgO) offers a catalytic method for the conversion of these gases into hydrogen and carbon monoxide through the dry reforming of methane (DRM) reaction. In the current research work, 1–4 wt% strontium is investigated as a cheap promoter over a 5Ni/MgO catalyst to modify the reducibility and basicity for the goal of excelling the H₂ yield and H₂/CO ratio through the DRM reaction. The fine catalytic activities’ correlations with characterization results (like X-ray diffraction, surface area porosity, photoelectron–Raman–infrared spectroscopy, and temperature-programmed reduction/desorption (TPR/TPD)) are established. The 5Ni/MgO catalyst with a 3 wt.% Sr loading attained the highest concentration of stable active sites and the maximum population of very strong basic sites. 5Ni3Sr/MgO surpassed 53% H₂ yield (H₂/CO ~0.8) at 700 °C and 85% H₂ yield (H₂/CO ratio ~0.9) at 800 °C. These outcomes demonstrate the catalyst’s effectiveness and affordability. Higher Sr loading (>3 wt%) resulted in a weaker metal–support contact, the production of free NiO, and a lower level of catalytic activity for the DRM reaction. The practical and cheap 5Ni3Sr/MgO catalyst is scalable in industries to achieve hydrogen energy goals while mitigating greenhouse gas concentrations. Full article

Staphylococcus aureus is the most common pathogen causing osteomyelitis, a hardly recoverable bone infection that generates significant burden to patients. Osteomyelitis mouse models have long and successfully served to provide phenomenological insights into both pathogenesis and host response. However, direct in situ monitoring of bone microbial pathogenesis and immune response at the cellular level is still conspicuously missing in the published literature. Here, we update a standard pyogenic osteomyelitis in Wistar rat model, in order to investigate bacterial localization and immune response in osteomyelitis of rat tibia upon adding in situ analyses by spectrally resolved Raman spectroscopy. Raman experiments were performed one and five weeks post infections upon increasing the initial dose of bacterial inoculation in rat tibia. Label-free in situ Raman spectroscopy clearly revealed the presence of Staphylococcus aureus through exploiting peculiar signals from characteristic carotenoid staphyloxanthin molecules. Data were collected as a function of both initial bacteria inoculation dose and location along the tibia. Such strong Raman signals, which relate to single and double bonds in the carbon chain backbone of carotenoids, served as efficient bacterial markers even at low levels of infection. We could also detect strong Raman signals from cytochrome c (and its oxidized form) from bone cells in response to infection and inflammatory paths. Although initial inoculation was restricted to a single location close to the medial condyle, bacteria spread along the entire bone down to the medial malleolus, independent of initial infection dose. Raman spectroscopic characterizations comprehensively and quantitatively revealed the metabolic state of bacteria through specific spectroscopic biomarkers linked to the length of staphyloxanthin carbon chain backbone. Moreover, the physiological response of eukaryotic cells could be quantified through monitoring the level of oxidation of mitochondrial cytochrome c, which featured the relative intensity of the 1644 cm⁻¹ signal peculiar to the oxidized molecules with respect to its pyrrole ring-breathing signal at 750 cm⁻¹, according to the previously published literature. In conclusion, we present here a novel Raman spectroscopic approach indexing bacterial concentration and immune response in bone tissue. This new approach enables locating and characterizing in situ bone infections, inflammatory host tissue reactions, and bacterial resistance/adaptation. Full article

Extraction processes of alginates from Sargassum spp. generate a substantial number of solid residues that are commonly discarded. This study explores the sustainable transformation of these residues into nitrogen-doped biocarbon through chemical activation with KOH and nitrogen doping using urea. XRD, FTIR, SEM-EDX, Raman spectroscopy, BET surface area analysis, XPS, and CHNS elemental analysis were used to characterize the materials. The doped and activated biocarbon (BDA) demonstrated excellent physicochemical properties, including a specific surface area of 1790 m² g⁻¹ and a mesoporous structure. Electrochemical evaluation in alkaline media revealed a current density of −4.37 mA cm⁻², an onset potential of 0.922 E vs. RHE, and a half-wave potential of 0.775 E vs. RHE. Koutecky–Levich analysis indicated a two-electron reduction pathway. The superior performance was attributed to the synergistic effects of high surface area, nitrogen functionalities (pyridinic-N and pyrrolic-N), and enhanced accessibility of active sites. These results highlight the potential of waste-derived, nitrogen-doped biocarbon as a sustainable and low-cost alternative for ORR electrocatalysis in alkaline fuel cells. Full article

Background/Objectives: Acute lymphoblastic leukemia (ALL) is the most prevalent childhood cancer requiring cytotoxic methotrexate treatment. This always necessitates intravenous administration of rescue therapy consisting of calcium folinate and bicarbonate. Current recommendations advise against mixing these two drugs due to concerns regarding precipitate formation of calcium carbonate (CaCO₃) that could result in catheter and capillary obstruction. These recommendations are based on drug concentrations not clinically relevant in pediatric ALL settings. Our study investigated the effect of clinically relevant calcium folinate–bicarbonate concentrations on the risk of CaCO₃ precipitation. Methods: A theoretical prediction model provided estimates of final mixing concentrations in five scenarios: three simulated pediatric patient models (approx. 1, 9, and 14 years), an undiluted drug mix, and a high-risk control outlier case. Physical compatibility tests were conducted using validated methods for particle detection, complemented by Raman spectroscopy for particle identification. Results: Theoretical predictions suggested CaCO₃ precipitation with elevated bicarbonate concentrations and pH levels. Our simulated patient models and high-risk control outlier case showed that CaCO₃ precipitation may be avoided below certain serum methotrexate concentrations and thereby calcium folinate and bicarbonate concentrations. Physical testing demonstrated particle formation only in the undiluted mix with Raman spectroscopy confirming the finding. Conclusions: Mixing calcium folinate and bicarbonate appears safe under specific methotrexate-directed pediatric ALL treatment conditions. While high bicarbonate concentrations pose precipitation risks, protocol-based dosing regimens mitigate this. Switching to disodium folinate or using in-line filters could further enhance co-administration safety if bicarbonate concentrations exceed the safety limit suggested by our results. Full article

Graphene quantum dots (GQDs) have emerged as promising nanomaterials due to their unique optical properties, high biocompatibility, and tunable surface functionalities. In this work, GQDs were synthesized via a one-pot hydrothermal method and further functionalized using polyethylene glycol (PEG) of various molecular weights and sodium hydroxide to tailor their photoluminescence (PL) behavior and enhance their applicability in thin-film illumination and biological staining. PEG-modified GQDs exhibited a pronounced red-shift and intensified fluorescence response due to aggregation-induced emission, with GQD-PEG (molecular weight: 300,000) achieving up to eight-fold enhancement in PL intensity compared to pristine GQDs. The influence of solvent environments on PL behavior was studied, revealing solvent-dependent shifts and emission intensities. Transmission electron microscopy confirmed the formation of core–shell GQD clusters, while Raman spectroscopy suggested improved structural ordering upon modification. The prepared GQD thin films demonstrated robust fluorescence stability under prolonged water immersion, indicating strong adhesion to glass substrates. Furthermore, the modified GQDs effectively labeled E. coli, Gram-positive, and Gram-negative bacteria, with GQD-PEG and GQD-NaOH displaying red and green emissions, respectively, at optimal concentrations. This study highlights the potential of surface-functionalized GQDs as versatile materials for optoelectronic devices and fluorescence-based bioimaging. Full article

Carbon nanotubes (CNTs) have remarkable mechanical, electrical, and thermal properties, making them highly attractive as foundational elements for advanced materials. However, translating their nanoscale potential into macroscale reliability and longevity requires a holistic design approach that integrates precise architectural control with robust damage mitigation strategies. This review presents a synergistic perspective on enhancing the durability of CNT-based systems by critically examining the interplay between molecular assembly, self-repair mechanisms, and the advanced characterization techniques required for their validation. We first establish how foundational architectural control—achieved through strategies like chemical functionalization, field-directed alignment, and dispersion—governs the ultimate performance of CNT materials. A significant focus is placed on advanced functionalization, such as fluorination, and its verification using high-powered spectroscopic tools, including X-ray photoelectron spectroscopy (XPS) and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. Subsequently, this manuscript delves into the mechanisms of self-repair, systematically analyzing both the intrinsic capacity of the carbon lattice to heal atomic-level defects and the extrinsic strategies that incorporate engineered healing agents into composites. This discussion is uniquely supplemented by an exploration of the experimental techniques, such as electron energy loss spectroscopy (EELS) and Auger electron spectroscopy (AES), that provide crucial evidence for irradiation-induced healing dynamics. Finally, we argue that a “characterization gap” has limited the field’s progress and highlight the critical role of techniques like in situ Raman spectroscopy for quantitatively monitoring healing efficiency at the molecular level. By identifying current challenges and future research frontiers, this review underscores that the creation of truly durable materials depends on an integrated understanding of how to build, repair, and precisely measure CNT-based systems. Full article

Food fraud in meat products presents serious economic and public health challenges, underscoring the need for rapid and reliable detection methods. This study investigates the potential of Raman spectroscopy combined with machine learning to accurately discriminate between pure and mixed minced meat preparations. We evaluated three classification algorithms: Support Vector Machines (SVMs), Artificial Neural Networks (ANNs), and Random Forests (RFs). Raman spectra were collected from 19 distinct samples consisting of different ratios of pork, beef, and lamb minced meat. Our findings suggest that homogenization markedly enhances spectral consistency and classification accuracy. In the pure meat samples case, all three models (SVM, ANN, and RF) achieved notable increases in classification accuracies (from 0.50–0.70 to above 0.85), a dramatic improvement over unhomogenized samples. In more complex homogenized mixtures, SVM delivered the highest performance, achieving an accuracy of up to 0.88 for 50:50 mixtures and 0.86 for multi-ratio samples, often outperforming both ANN and RF. While the underlying interpretation of the classification models remains complex, the findings consistently underscore the critical role of homogenization on model performance. This work demonstrates the robust potential of the Raman spectroscopy-coupled machine learning approach for the rapid and accurate identification of minced meat species. Full article