Search Results (946)

In this work, the effect of aqueous dispersions of graphene oxide (GO) and nanosized graphene oxide (nGO) on the enzymatic polymerization of polyaniline (PANI) was studied. The enzymatic polymerization of PANI was carried out in aqueous medium using toluenesulfonic acid (TSA) as the dopant, horseradish peroxidase (HRP) as the catalyst, and hydrogen peroxide (H₂O₂) as the oxidant, using 1.0, 2.5, and 5.0 wt% of GO and nGO. The morphology of PANI-GO/nGO composites was studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Further characterization was performed by thermogravimetric analysis (TGA) and spectroscopic techniques such as ultraviolet–visible (UV–Vis), Fourier-transform infrared (FTIR), Raman and X-ray photoelectronics (XPS). SEM images showed that during enzymatic polymerization, PANI completely covers the GO/nGO sheets. Furthermore, physicochemical results confirmed the production of a hybrid PANI-GO/nGO material with Van der Waals-type interactions between the oxygen-based functional groups of GO and the secondary amino bond (-NH-) of PANI. Also, cyclic voltammetry experiments were carried out in situ during the polymerization of PANI-GO/nGO films. The electrochemical response of PANI-GO/nGO composites reflects two broad oxidation peaks around 300 mV and 500 mV during anodic scanning, with reversible oxidation during cathodic scanning. Classical molecular dynamics simulations were used to understand the mechanism of the composite film’s growth. Full article

Green synthesis methods of silver nanoparticles have gained great attention because they offer sustainable, eco-friendly, and less-toxic alternatives to traditional methods. This study sheds light on the green synthesis of chitosan silver nanoparticle composites, providing a comparative evaluation of microwave-assisted (M1) and a one-pot (M2) reduction methods. The morphological, crystallinity, and structural uniformity characteristics were evaluated by UV-Visible, Raman spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM) with employing image processing pipeline based on deep learning model for segmentation and particles size estimation. The UV-visible spectrum exhibited independent SPR peaks ranging from 400 to 450 nm for all samples; however, microwave assisted-synthesis possessed narrower and more intense peaks indicative of better crystallinity and mono-dispersity. SEM depicted smaller, more uniformly dispersed particles for microwave-assisted (M1), while deep learning segmentation showed lower particle size variability (σ ≈ 24–43 nm), compared to polydisperse (σ ≈ 16–59 nm) in M2 samples. XRD showed crystalline face-centered cubic (FCC) silver with dominant peaks in M1 samples, whereas M2 had broader, less intense peaks with amorphous features. Raman vibrations revealed more structural order and homogenous capping in M1 than M2. Therefore, microwave-assisted (M1) showed better control on nucleation, particle size, crystallinity, and homogeneity due to a faster and uniform energy distribution. The future research would focus on the antimicrobial evaluation of such nanoparticles in agronomy. Full article

To investigate the long-term water stability of graphene-modified permeable asphalt mixtures, in this study, we analysed the effects of single factors and multi-factor coupling. The single-factor water stability was investigated through the free thawing splitting test, standard Cantabro test, and immersion Cantabro test; the experimental indicators were the freeze–thaw cracking ratio (TSR), mass loss rate, and immersion mass loss rate, respectively. The multi-factor water stability was studied through immersion operation tests of mixtures with different degrees of ageing. The dispersion of graphene was examined through Raman mapping, the formation of three-dimensional network structures of graphene and SBS was evaluated via the dynamic shear rheometer test (DSR), and the elemental distribution was quantitatively analysed using energy-dispersive spectroscopy (EDS) and an image pixel algorithm (RGB). The results indicate that an unaged graphene-composite- and SBS-modified permeable asphalt mixture with an optimal graphene content of 0.05% demonstrated a 4.5% improvement in the TSR, alongside reductions in the mass loss rate and water immersion mass loss rate of 25.64% and 23.52%, respectively. Even after prolonged thermal oxygen ageing, its TSR, mass loss rate, and water immersion mass loss rate improved by 5.1%, 23.04%, and 20.70%, respectively. Multi-factor coupling tests confirmed that the water stability met requirements under severe conditions, with better performance at high temperatures. Graphene was uniformly dispersed in the modified asphalt. The appearance of a plateau region at low frequencies in graphene-composite- and SBS-modified asphalt verified the formation of a three-dimensional network structure, and the oxygen content was positively correlated with deepening thermal oxidative ageing. Full article

As global agriculture shifts to intelligence and precision, crop attribute detection has become foundational for intelligent systems (harvesters, UAVs, sorters). It enables real-time monitoring of key indicators (maturity, moisture, disease) to optimize operations—reducing crop losses by 10–15% via precise cutting height adjustment—and boosts resource-use efficiency. This review targets harvesting-stage and in-field monitoring for grains, fruits, and vegetables, highlighting practical technologies: near-infrared/Raman spectroscopy (non-destructive internal attribute detection), 3D vision/LiDAR (high-precision plant height/density/fruit location measurement), and deep learning (YOLO for counting, U-Net for disease segmentation). It addresses universal field challenges (lighting variation, target occlusion, real-time demands) and actionable fixes (illumination compensation, sensor fusion, lightweight AI) to enhance stability across scenarios. Future trends prioritize real-world deployment: multi-sensor fusion (e.g., RGB + thermal imaging) for comprehensive perception, edge computing (inference delay < 100 ms) to solve rural network latency, and low-cost solutions (mobile/embedded device compatibility) to lower smallholder barriers—directly supporting scalable precision agriculture and global sustainable food production. Full article

This paper provides an overview of thin-layer chromatography (TLC) and high-performance thin-layer chromatography (HPTLC) methods for analyzing plant materials and herbal formulations, as described in scientific publications from January 2022 to July 2025. It describes the use of TLC in the qualitative and quantitative examination of plant materials and pharmaceutical preparations containing herbs, including profiling plant materials using TLC and applying it to HPTLC plates. It also describes other modern methods that improve component separations, such as applying TLC to profile plant formulations and detect adulterations and contaminants in them. Additionally, it discusses TLC coupled with other methods, such as principal component analysis (PCA), hierarchical cluster analysis (HCA), orthogonal partial least squares discriminant analysis (OPLS-DA), mass spectrometry (MS), nuclear magnetic resonance (NMR), surface-enhanced Raman spectroscopy (SERS), and image analysis (IA). The quantitative determination of biologically active compounds in herbs and herbal formulations is presented based on methods that combine TLC with densitometry. The paper also discusses TLC with effect-oriented analysis, including the detection of antimicrobial, antioxidant, enzyme-inhibiting, endocrine-disrupting, genotoxic, and cytotoxic substances. The advantages, disadvantages, and prospects of analyzing plant material using the TLC technique are indicated. TLC/HPTLC has great prospects for use by regulatory authorities due to the low cost of analysis and high throughput. Full article

Background/Objectives: Breast cancer (BC) has emerged as a significant threat among female malignancies, resulting in approximately 670,000 fatalities. The capacity to identify BC has advanced over the past two decades because of deep learning (DL), machine learning (ML), and artificial intelligence. The early detection of BC is crucial; yet, conventional diagnostic techniques, including MRI, mammography, and biopsy, are costly, time-intensive, less sensitive, incorrect, and necessitate skilled physicians. This narrative review will examine six novel imaging approaches for BC diagnosis. Methods: Optical coherence tomography (OCT) surpasses existing approaches by providing non-invasive, high-resolution imaging. Raman Spectroscopy (RS) offers detailed chemical and structural insights into cancer tissue that traditional approaches cannot provide. Photoacoustic Imaging (PAI) provides superior optical contrast, exceptional ultrasonic resolution, and profound penetration and visualization capabilities. Hyperspectral Imaging (HSI) acquires spatial and spectral data, facilitating non-invasive tissue classification with superior accuracy compared to grayscale imaging. Contrast-Enhanced Spectral Mammography (CESM) utilizes contrast agents and dual energy to improve the visualization of blood vessels, enhance patient comfort, and surpass standard mammography in sensitivity. Multispectral Imaging (MSI) enhances tissue classification by employing many wavelength bands, resulting in high-dimensional images that surpass the ultrasound approach. The imaging techniques studied in this study are very useful for diagnosing tumors, staging them, and guiding surgery. They are not detrimental to morphological or immunohistochemical analysis, which is the gold standard for diagnosing breast cancer and determining molecular characteristics. Results: These imaging modalities provide enhanced sensitivity, specificity, and diagnostic accuracy. Notwithstanding their considerable potential, the majority of these procedures are not employed in standard clinical practices. Conclusions: Validations, standardization, and large-scale clinical trials are essential for the real-time application of these approaches. The analyzed studies demonstrated that the novel modalities displayed enhanced diagnostic efficacy, with reported sensitivities and specificities often exceeding those of traditional imaging methods. The results indicate that they may assist in early detection and surgical decision-making; however, for widespread adoption, they must be standardized, cost-reduced, and subjected to extensive clinical trials. This study offers a concise summary of each methodology, encompassing the methods and findings, while also addressing the many limits encountered in the imaging techniques and proposing solutions to mitigate these issues for future applications. Full article

This review summarizes the application of spectroscopic techniques in pesticide residue analysis, with a focus on the principles, advancements, and challenges of surface-enhanced Raman spectroscopy (SERS), infrared spectroscopy, fluorescence spectroscopy, ultraviolet-visible (UV-Vis) spectroscopy, and hyperspectral imaging (HSI). Nanomaterials, serving as key enhancing substrates, significantly improve the sensitivity and selectivity of these detection methods. This article critically evaluates the strengths and limitations of each technique in practical applications—such as the exceptional sensitivity of SERS versus its dependence on substrate reproducibility, and the non-destructive nature of hyperspectral imaging against the complexity of data processing. Future research directions should emphasize the development of intelligent nanosubstrates, the construction of cross-modal spectral databases, and the miniaturization of integrated spectroscopic-mass spectrometric instruments. These advancements are essential for enhancing the efficiency and reliability of agricultural and food safety monitoring. Full article

Optical fiber technology is becoming essential in modern radiation therapy, enabling precise, real-time, and minimally invasive monitoring. As oncology moves toward patient-specific treatment, there is growing demand for adaptable and biologically compatible sensing tools. Fiber-optic systems meet this need by integrating into clinical workflows with highly localized dosimetric and spectroscopic feedback. Their small size and flexibility allow deployment within catheters, endoscopes, or treatment applicators, making them suitable for both external beam and internal therapies. This paper reviews the fundamental principles and diverse applications of optical fiber sensing technologies in radiation oncology, focusing on dosimetry, spectroscopy, imaging, and adaptive radiotherapy. Implementations such as scintillating and Bragg grating-based dosimeters demonstrate feasibility for in vivo dose monitoring. Spectroscopic techniques, such as Raman and fluorescence spectroscopy, offer real-time insights into tissue biochemistry, aiding in treatment response assessment and tumor characterization. However, despite such advantages of optical fiber sensors, challenges such as signal attenuation, calibration demands, and limited dynamic range remain. This paper further explores clinical application, technical limitations, and future directions, emphasizing multiplexing capabilities, integration and regulatory considerations, and trends in machine learning development. Collectively, these optical fiber sensing technologies show strong potential to improve the safety, accuracy, and adaptability of radiation therapy in personalized cancer care. Full article

Volatile organic compound (VOC) monitoring is crucial for environmental safety and health, but conventional gas sensors often suffer from poor selectivity or lack spatial information. Here, we report a localized surface plasmon resonance (LSPR) gas sensor based on Au nano-urchins coated with a zeolitic imidazolate framework (ZIF-8) for both the quantitative detection and visualization of VOCs. Substrates were fabricated by immobilizing Au nano-urchins (~90 nm) on 3-aminopropyltriethoxysilane-modified glass and subsequently growing ZIF-8 crystals (~250 nm) for different durations. Scanning electron microscopy and optical analysis revealed that 90 min of ZIF-8 growth provided the optimal coverage and strongest plasmonic response. Using a spectrometer-based LSPR system, the optimized substrate exhibited clear, concentration-dependent responses to three representative VOCs, 2-pentanone, acetic acid, and ethyl acetate, over nine concentrations, with detection limits of 12.7, 14.5, and 36.3 ppm, respectively. Furthermore, a camera-based LSPR visualization platform enabled real-time imaging of gas plumes and evaporation-driven diffusion, with differential pseudo-color mapping providing intuitive spatial distributions and concentration dependence. These results demonstrate that ZIF-8-modified Au nano-urchin substrates enable sensitive and reproducible VOC detection and, importantly, transform plasmonic sensing into a visual modality, offering new opportunities for integrated LSPR–surface-enhanced Raman scattering dual-mode gas sensing in the future. Full article

In this work, molecular and elemental spectroscopic analyses were carried out on the preparation base, the paintings, the repaintings, and the gilding of an 18th century sacred sculpture of Our Lady found on Anhatomirim Island, where the Santa Cruz fortress was built in 1739 in the state of Santa Catarina, southern Brazil. The preparation base of the sculpture was characterized as gypsum (calcium sulfate dihydrate, (CaSO₄.2H₂O) [µ-Raman, SEM-EDS], applied directly to the wooden support. The blue paint comprised a mixture of Prussian blue (Fe₄[Fe(CN)₆]₃) and ultramarine (Na_xAl₆Si₆O₂₄S_x) [µ-Raman, FTIR, SEM-EDS]; hematite (Fe₂O₃) was identified in the brown paint [µ-Raman, SEM-EDS]; and the white paint consisted of lead white (2 PbCO₃·Pb(OH)₂) [µ-Raman, FTIR, SEM-EDS]. Repainted areas were identified by the presence of lithopone (ZnS + BaSO₄) [µ-Raman, SEM-EDS, FTIR], likely resulting from later interventions. In the gilded areas, gold was identified along with traces of iron [SEM-EDS], indicating a lower-quality gilding compared to, for example, silver alloys. Lead white was also identified in the polychrome areas, where it served to produce different tones in the painting. FTIR analyses revealed traces of aged oil used as a binder in the older layers. Mineral oil was detected in some samples, which may indicate that wax was used as a protective layer on the sculpture. The results will assist professionals in the iconographic characterization of the sacred image of Our Lady and in the conservation and restoration processes based on the identified constituent materials. Full article

Optical imaging technologies expand gastrointestinal endoscopy beyond white-light endoscopy (WLE), improving visualization of mucosal, vascular, and subsurface features. They are applied to the detection of neoplastic and premalignant lesions, inflammatory diseases, and small bowel and pancreatic disorders, though their validation and readiness for routine practice vary. This review critically evaluates both guideline-endorsed and investigational optical imaging techniques across major gastrointestinal indications, highlighting diagnostic performance, level of validation, current guideline recommendations, and practical challenges to adoption. In Barrett’s esophagus, narrow-band imaging (NBI) is guideline-endorsed, while acetic acid chromoendoscopy is validated in expert centers. For gastric intestinal metaplasia and early gastric cancer, magnifying NBI achieves diagnostic accuracies exceeding 90% and is guideline-recommended, with acetic acid chromoendoscopy aiding in margin delineation. In inflammatory bowel disease, dye-spray chromoendoscopy is the reference standard for dysplasia surveillance, with virtual methods such as NBI, FICE, and i-SCAN serving as practical alternatives when dye application is not feasible. In the colorectum, NBI supports validated optical diagnosis strategies (resect-and-discard, diagnose-and-leave), while dye-based chromoendoscopy improves detection of flat and serrated lesions. Capsule endoscopy remains the standard for small bowel evaluation of bleeding, Crohn’s disease, and tumors, with virtual enhancement, intelligent chromo capsule endoscopy, and AI-assisted interpretation emerging as promising adjuncts. Pancreaticobiliary applications of optical imaging are also advancing, though current evidence is still preliminary. Investigational modalities including confocal laser endomicroscopy, optical coherence tomography, autofluorescence, Raman spectroscopy, and fluorescence molecular imaging show potential but remain largely restricted to research or expert settings. Guideline-backed modalities such as NBI and dye-based chromoendoscopy are established for clinical practice and supported by robust evidence, whereas advanced techniques remain investigational. Future directions will rely on broader validation, integration of artificial intelligence, and adoption of molecularly targeted probes and next-generation capsule technologies, which together may enhance accuracy, efficiency, and standardization in gastrointestinal endoscopy. Full article

Surface-enhanced Raman spectroscopy (SERS) enables ultra-sensitive molecular detection and has broad analytical and biomedical applications; recent advances focus on high-performance substrates and innovative detection strategies. However, achieving controllable and reproducible substrate fabrication—particularly using natural templates such as hair—remains challenging, limiting SERS application in trace analysis and on-site detection. This study developed a single-hair in situ SERS platform using a natural hair template. Confinement within hair cuticle grooves and capillary-evaporation assembly enables dense arrangement of cetyltrimethylammonium bromide-coated Au nanorods and polyvinylpyrrolidone-coated Au nanoparticles, forming uniform plasmonic nanoarrays. Spectroscopy and microscopy analyses confirmed the regular alignment of nanostructures along the hair axis with denser packing at the edges. The platform detected crystal violet at 10⁻⁹ M, yielding clear signals, negligible background, and stable peaks after repeated washing. For p-phenylenediamine, enhancement was observed down to 10⁻⁶ M. On the platform, a concentration-dependent response appeared within 10⁻³–10⁻⁵ M, with spatial Raman imaging along the hair axis. Capillary-evaporation coupling and interfacial wettability facilitated solute enrichment from larger to smaller gap hotspots, improving signal-to-noise ratio and reproducibility. This portable, low-cost, and scalable method supports rapid on-site screening in complex matrixes, offering a general strategy for hotspot engineering and programmable assembly on natural templates. Full article

The optical microscope is an indispensable observation instrument that has fundamentally contributed to progress in science and technology. Dark-field microscopy and scattered light imaging techniques enable high-contrast observation of nanoparticles in water. However, the scattered light is focused by the optical lenses, resulting in a blurred image of the nanoparticle structure. Here, we developed a projection optical microscope (PROM), which directly observes the scattered light from the nanoparticles without optical lenses. In this method, the sample is placed below the focus position of the microscope’s objective lens and the projected light is detected by an image sensor. This enables direct observation of the sample with a spatial resolution of approximately 20 nm. Using this method, changes in the aggregation state of nanoparticles in solution can be observed at a speed faster than the video frame rate. Moreover, the mechanism of such high-resolution observation may be related to the quantum properties of light, making it an interesting phenomenon from the perspective of optical engineering. We expect this method to be applicable to the observation and analysis of samples in materials science, biology and applied physics, and thus to contribute to a wide range of scientific, technological and industrial fields. Full article

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. Full article

Advancements in Raman spectroscopy have broadened the utilization possibilities for food applications. The present review covers the working principle and methodology of the emerging technique in the context of wheat (flour) as a bakery ingredient. Special attention is paid to the primary constituents of wheat flour, starch and gluten proteins, both in their isolated forms and within complex matrices such as flour, dough, and various end products. This review examines how compositional and structural variations in these components are reflected in their Raman spectra and imaging characteristics and how this can be interpreted in terms of quality and functionality. The review concludes by outlining prospective research directions and future opportunities for advancing Raman-based analysis in cereal and bakery science. Full article