Vibrational energy exchange is a fundamental process that governs how proteins overcome energy barriers during their function, and heme proteins are excellent model systems for its investigation. The migration of excess energy released by the heme prosthetic group can be directly monitored using time-resolved anti-Stokes ultraviolet resonance Raman spectroscopy. Crucially, the anti-Stokes Raman intensity from a tryptophan residue acts as an exquisite probe for this excess energy, enabling its location to be mapped with single-amino-acid spatial resolution. Here, we investigated the dependence of vibrational energy transfer on the orientation of the heme and tryptophan residue within nitrobindin from Arabidopsis thaliana, a β-barrel protein containing a heme group. Tryptophan residues were systematically introduced into the protein's cylindrical structure to sample the excess energy in the heme's vicinity for different spatial orientations of the residues. By combining time-resolved anti-Stokes ultraviolet and visible resonance Raman spectroscopy-which selectively probe tryptophan residues and the heme group, respectively-we revealed that the vibrational energy transfer from the heme group to its immediate surroundings in nitrobindin is ultrafast and orientationally anisotropic, with atomic contacts within the protein playing a critical role.

Molecular interaction of pristine and photoaged polylactic acid microplastics with extracellular polymeric substances from Microcystis aeruginosa.

Silica nanoparticles (SiNPs) are widely explored as biocompatible platforms for the delivery of photosensitizers in photodynamic therapy (PDT). In this work, porphyrins bearing amine (PNH2) or carboxyl (PCOOH) groups were covalently conjugated onto functionalized SiNP surfaces via carbodiimide-mediated amide coupling, yielding the silica–porphyrin nanohybrids H-PNH2 and H-PCOOH. Successful surface functionalization was confirmed by Fourier-transform infrared spectroscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy. Photophysical studies demonstrated that both nanohybrids retained efficient singlet oxygen (1O2) generation. In vitro biological assays revealed a strong dependence of photodynamic activity on the nature of the conjugated porphyrin, with H-PCOOH exhibiting markedly enhanced photocytotoxicity with respect to the free porphyrins, while H-PNH2 showed an attenuated light-dose response. Notably, H-PCOOH induced pronounced cell death at low light doses (1 J/cm2), with a half-maximal inhibitory concentration (IC50) below 0.3 µM. These findings highlight the potential of silica–porphyrin nanohybrids as efficient photosensitizers for PDT applications.

The present work reports a novel borate layered CeMgB3O7 crystal with an orthorhombic lattice (Cmme) as determined by single-crystal X-ray diffraction, which was synthesized through high-pressure solid-state metathesis reaction, marking the first successful preparation of that type of structure under high pressure and high temperature. Using multimodal characterization techniques, including in situ high-pressure synchrotron radiation X-ray diffraction and Raman spectroscopy, the exceptional structural stability of CeMgB3O7 was confirmed up to 34 GPa. X-ray photoelectron spectroscopy measurements and the photoluminescence (PL) spectroscopy further identified a novel pathway for achieving near-infrared emission in Ce-based materials, highlighting the potential of defect engineering to directly activate luminescent centers within the host lattice in CeMgB3O7. The high-pressure PL spectroscopy indicates that applied pressure effectively modulates the crystal field splitting degree in [CeO10]17-, imposing a direct and tunable influence on its intrinsic luminescence. These findings advance the understanding of luminescence mechanisms in Ce-based systems and offer new insights for the future design of luminescent materials.

Applications of Raman and FTIR Spectroscopy in Monitoring Antibiotic Residues in Bovine Milk: A Critical Overview

Ophiocordyceps sinensis (Berk.) is a functional food with health. O. sinensis quality varies by geographical origins, and current identification methods are sophisticated and time-consuming. This study aims to develop a rapid and straightforward method for accurately identifying O. sinensis geographic origins. Surface-enhanced Raman spectroscopy (SERS) was applied to analyze O. sinensis from four major production areas in China. Liquid chromatography-mass spectrometry (LC-MS) was used as a reference method to characterize compositional differences among samples and to verify the geographical authenticity of O. sinensis from the four production areas. Six machine learning (ML) algorithms were introduced for predicting geographical origins, and evaluation metrics were used to assess model performance. According to the comparative analysis, the Support Vector Machine (SVM) model performed best with the highest discrimination accuracy. A feature importance map was constructed to understand further how the model makes predictive decisions, revealing the significant Raman shifts in classifying O. sinensis from different geographical origins. The SERS-SVM method developed in this study contributes to the authenticity identification of O. sinensis geographical origins. It shows the potential to serve as an effective quality control method for the valuable TCM (traditional Chinese medicine).

Ex vivo digital microscopy uses light in the visible and adjacent spectra to obtain digital images of tissues. They are optical imaging techniques that allow the acquisition of digital images of tissues with minimal or no tissue preparation and are currently available for evaluation of fresh and/or fixed tissues. This review will provide an overview of the different types of ex vivo digital microscopy techniques, including confocal microscopy (CM), optical coherence tomography (OCT), stimulated Raman Spectroscopy (SRS), light sheet microscopy (LSM), microscopy with ultraviolet excitation (MUSE), structured illumination microscopy (SIM), and nonlinear microscopy (NLM). Except for OCT and SRS, all the other tissue imaging techniques require labeling of tissues with fluorescent dyes to obtain digital images. An advantage of several of these techniques, including fluorescence CM, SRS, LSM, MUSE, SIM, and NLM, is that they can produce hematoxylin and eosin-like images. The promising potential of ex vivo digital microscopy techniques in surgical pathology practice is supported by several retrospective and limited prospective studies. Applications of ex vivo digital microscopy techniques include real-time evaluation of fresh tissue at the bedside in clinics and radiology suites, as well as intraoperatively in pathology laboratories. These techniques have great potential for incorporation into standard-of-care surgical pathology practice.

Polymeric electrolyte membranes based on a low equivalent-weight Aquivion® commercial dispersion (D72-25BS; EW = 720 g eq−1, Syensqo) were fabricated using a standardized in-house doctor-blade casting technique for application in proton exchange membrane fuel cells (PEMFCs). The low equivalent-weight (EW) Aquivion® dispersion is a copolymer of tetrafluoroethylene (TFE) and sulfonyl fluoride vinyl ether (SFVE), commonly referred to as a short-side-chain (SSC) ionomer, which exhibits higher ion-exchange capacity (IEC) and proton conductivity than long-side-chain (LSC) perfluorosulfonic membranes. A home-made 30 wt.% Pt/CeO2 radical scavenger (denoted syn-scavenger) was synthesized via a colloidal method and incorporated into the Aquivion® membranes to investigate its mitigating effect on chemical degradation induced by peroxide radicals, a role typically associated with Ce-based scavengers. Particularly, the unique aspects of the Pt/CeO2 scavenger synthesis could be summarized in the following points: (i) the mild aqueous deposition approach enabling highly dispersed Pt species on CeO2 without the use of organic ligands; and (ii) the tailored redox interaction between Pt and ceria that enhances radical scavenging activity. Two Aquivion® membranes (denoted Aqu) containing different syn-scavenger loadings (1.0 and 1.5 wt.%) were prepared and compared with a pristine Aquivion® membrane and a membrane containing commercial CeO2 (1.0 wt.%). Physicochemical characterization of the scavenger was performed using transmission electron microscopy (TEM), BET surface area analysis, and X-ray diffraction (XRD). The membranes were characterized by micro-Raman spectroscopy, water uptake and hydration number (λ), IEC, and proton conductivity measurements. To assess membrane stability, exsitu chemical oxidative degradation tests were conducted using Fenton’s reagent. Overall, the membrane containing 1.0 wt.% syn-scavenger emerged as the most promising candidate, exhibiting favourable chemical–physical properties and the lowest reductions in IEC and proton conductivity following the degradation test.

Nickel-supported catalysts over SiO2-CeO2 mixed oxides were investigated as catalysts for syngas production via dry reforming of methane. SiO2-CeO2 supports were optimized by varying the preparation method and ceria loading with the aim of stabilizing nickel nanoparticles, enhancing the catalytic performance, and improving the resistance to coke formation under high-temperature reforming conditions. To investigate the effect of support composition, SiO2-CeO2 mixed oxides with ceria contents ranging from 5 to 30 wt% were prepared using two synthesis routes: sol–gel and wetness impregnation methods. A nickel loading of 5 wt% was deposited on the resulting supports. The catalysts were characterized by XRD, N2 physisorption, temperature-programmed reduction (TPR), and Raman spectroscopy. Catalytic activity tests were carried out over reduced catalysts in an H2-He stream at 750 °C, using a feed mixture containing 15 vol% CH4 and 15 vol% CO2 in He. The effect of temperature on catalytic performance was evaluated in the range of 450–750 °C. Thermogravimetric, XRD and Raman analyses of spent catalysts were used to assess carbon deposition and the nature of crystalline phases. The results highlight the role of CeO2 content and preparation method in determining nickel dispersion, reducibility, catalytic performance in DRM, and coke resistance.

Solid-state electrolytes have been identified as promising candidates to overcome limitations of lithium-sulfur batteries in polysulfide shuttle and lithium dendrite growth. However, an essential mechanistic understanding of composite sulfur (S) cathodes is still lacking in all-solid-state lithium-sulfur (ASSLS) batteries. Herein, in situ atomic force microscopy and Raman spectroscopy were conducted to unravel S cathode processes during cycling. The S particles gradually expand and fuse upon discharge, which is ascribed to the electrochemical conversion to lithium sulfide. The volume variation exhibits poor reversibility upon charge, which is the origin of the capacity fading of the S cathode. Moreover, side reactions occur at the interface of S/Li10GeP2S12 (LGPS) in the cathode, manifested as simultaneous S dissolution and LGPS decomposition, which aggravate consumption of active materials and increase ion transport resistance. These straightforward evidence and in-depth studies uncover the S cathode process and enrich fundamental comprehensions of reaction mechanisms in ASSLS batteries.

In this paper, a study on the development of indium-doped CuxS heterojunction-based conductometry sensors is presented. To fabricate the sensors, thick films of In-CuxS heterojunctions were sprayed directly on the alumina sensing platform provided with interdigitated Pt electrodes. The effect of the doping level with different nominal amounts of InCl3 additive (0%, 3%, and 5%) on the structural, morphological and optical properties of CuxS films was first studied by XRD, AFM, UV-Vis and Raman spectroscopy. Moreover, the electrical and sensing characteristics towards low concentrations of hydrogen sulfide (H2S) in air were investigated. The tests carried out clearly demonstrated the positive effect of In doping on the H2S sensing performance of CuxS. The 5%-doped CuxS sensor showed the highest sensitivity to the target gas compared to the other sensor, as well as good stability and selectivity properties.

Abstract Conductive inks play a vital role in the advancement of printed electronics, where high conductivity, flexibility, low cost, and substrate compatibility are essential. Conventional metal nanoparticle-based inks, however, remain constrained by high production costs and limited flexibility. In the present study, graphite recovered from waste dry-cell batteries was electrochemically exfoliated in ammonium persulfate (NH4)2S2O8 electrolyte to obtain graphene oxide (GO) through a sustainable, low-cost route. The exfoliated GO was subsequently subjected to thermal reduction to produce reduced graphene oxide (rGO), which served as the active conductive material for ink formulation. For preparing the graphene ink, rGO was dispersed in an 80:20 ethanol–deionized (DI) water mixture (100 mL) containing 2% (w/v) polyvinylpyrrolidone (PVP), which acted as both solvent medium and stabilizer to ensure long-term dispersion stability. Structural and morphological analyses (XRD, Raman spectroscopy and SEM) confirmed the formation of few-layer rGO with moderate disorder. The formulated rGO-based graphene ink exhibited suitable rheological and surface properties for screen printing, and printed films on polyethylene terephthalate (PET) substrates displayed uniform, well-adhered patterns with an electrical conductivity of 2.186 × 103 S/m. Overall, this work presents an environmentally sustainable and cost-effective approach to graphene ink preparation from waste resources, offering a promising platform for flexible and printed electronic applications.

Abstract Oxide scale formation during thin-slab continuous casting has a complex structure, which is influenced by mold flux contamination, that modifies interfacial reactions during solidification, subsequent reheating, and descaling. While individual aspects of the oxidation behavior of carbon steel have been previously examined, the synergetic effects of mold flux contamination during continuous casting and subsequent reheating on scale modification and the efficiency of hydraulic descaling remain inadequately studied. This study quantitatively examines the effect of flux composition on oxide scale evolution, adhesion, and hydraulic removal in low-carbon steel under simulated industrial conditions. Slab samples with as-cast, cleaned, and flux-coated surfaces were reheated to 1065 °C in a controlled oxidizing atmosphere and immediately descaled using a computer numerical control (CNC)-controlled high-pressure water-jet system. The developed procedures closely simulate industrial conditions. The resulting scale morphologies and residuals after descaling were analyzed using cross-sectional scanning electron microscopy (SEM), Raman spectroscope and quantified through image J analysis. The results demonstrate that the mold flux composition significantly affects the structural evolution and adhesion characteristics of the oxide scale, thereby influencing its hydraulic removal performance.

Nitrogen-doped carbon quantum dots (NCQDs) were synthesized via a facile and optimized hydrothermal method. The as-prepared CQDs were comprehensively characterized using AFM, HRTEM, DLS, ζ-potential, EDX, XRD, Raman, FTIR, UV-Vis, and fluorescence spectroscopy, confirming their nanoscale dimensions, graphitic structure, abundant nitrogen- and oxygen-containing surface functionalities, and excellent aqueous dispersibility. The CQDs exhibited strong blue fluorescence with excitation-independent emission and a relatively high quantum yield of 37.8%. Their fluorescence stability was systematically evaluated over a wide range of pH values, ionic strengths, and solvent environments, demonstrating robust optical performance. Importantly, the fluorescence sensing behavior toward Fe3+ ions was critically examined under different pH conditions, revealing that Fe3+ detection in alkaline media is severely hindered by Fe(OH)3 precipitation, which leads to misleading quenching effects. By conducting sensing experiments under strongly acidic conditions (pH = 2), where Fe3+ remains fully soluble, a clear and reliable fluorescence quenching response was achieved over a wide linear range (20-1000 µM), with a detection limit of 10.25 µM. In addition, the practical applicability of the CQDs was demonstrated through fluorescent ink and CQDs/PVA composite films.

Enhancing the solubility and processability of graphene remains a critical challenge, limiting its integration into advanced materials systems. In this work, poly(tert-butyl acrylate) (PtBA) and poly(N-isopropyl acrylamide) (PNIPAM) were grafted onto graphene via controlled atom transfer radical polymerization (ATRP) to create well-defined polymer–graphene hybrids with tunable interfacial properties. ATRP enabled the synthesis of PtBA and PNIPAM homopolymers with narrow molecular weight distributions and systematically varied chain lengths (4–18 kDa), allowing direct correlation between polymer architecture and material performance. Notably, the thermos-responsive behavior of PNIPAM was strongly dependent on chain length, highlighting the importance of controlled polymer design. Raman and FTIR spectroscopy confirmed successful grafting and chemical modification of the graphene surface. In addition, pilot studies demonstrate the ATRP synthesis of PtBA-b-PNIPAM block copolymers and their hydrolysis to PAA-b-PNIPAM, providing a platform for future development of multifunctional graphene interfaces. Overall, this study establishes a versatile and precisely controlled route for engineering polymer-grafted graphene with enhanced solubility and tunable functionality, enabling broader applications in smart materials and hybrid nanocomposites.

Gluten proteins are key components in wheat flour that determine the formation of dough and the quality of flour-based products. Upon hydration and mixing, gluten proteins undergo complex structural transformations to form a gluten network, exhibiting a hierarchical multi-scale structure spanning molecular, aggregate, and network scales. Due to the extreme complexity of gluten proteins, accurately characterizing their multi-scale structures remains challenging, requiring the combined application of multiple techniques, which are still relatively limited and thus warrant further exploration. Therefore, this review presents the principles, operational details, and result presentations of current techniques at different structural scales, including electrophoresis, high-performance liquid chromatography, proteomics, Fourier transform infrared spectroscopy, and Fourier transform Raman spectroscopy at the molecular scale; size-exclusion chromatography, asymmetrical flow field-flow fractionation, dynamic light scattering, multi-angle light scattering, differential refractive index, and ultraviolet absorbance at the aggregate scale; and confocal laser scanning microscopy, scanning electron microscopy, confocal Raman microscopy, and two-photon excitation microscopy at the network scale, among others. It further compares the advantages and disadvantages of similar techniques, facilitating their scenario-based selective utilization. Finally, it outlines the ongoing challenges and future perspectives for the development and application of techniques for the multi-scale structural characterization of gluten proteins.

The interplay of topology and chirality in non-symmorphic chiral crystals unveils novel quantum phenomena such as chiral anomalies and exotic fermionic excitations with extended Fermi arcs. In this study, we unify two seemingly distinct concepts topological phonons, arising from non-trivial band topology, and chiral phonons, associated with circular polarization and non-zero angular momentum through the lens of Weyl phonons in chiral CoGe phase. Using first-principles calculations, symmetry analysis, and effective modeling, we reveal the entanglement of chiral and topological phonons in the P 2 1 3 phase of CoGe. We show that crystal chirality dictates topological charge, mirror enantiomers host Weyl phonons with opposite charges, distinct surface states, and reversed arc connections. Remarkably, we identify quadruple two-fold degenerate Weyl nodes with a Chern number of ±4 the highest reported for phononic systems. Due to the C 3 rotational symmetry along the Γ-R direction, chiral phonon modes emerge naturally, with circular polarization reversing under mirror operations mirroring the topological charge reversal.We propose helicity-resolved Raman spectroscopy as a powerful tool to detect these chiral phonons, linking circular polarization to Berry curvature and phonon angular momentum.Additionally, we explore a distorted kagome lattice phase (space group P-62m) of CoGe, predicting Dirac nodal lines and triply degenerate phonon points. In this achiral structure, valley-selective chiral phonons emerge at ±K(±H) points, exhibiting opposite circular polarization. Our findings establish CoGe as a versatile platform to explore a wide range of phononic topological quasiparticles, including spin-1/2 Weyl, spin-1 Weyl, charge-2 Dirac, charge-4 Weyl, Dirac nodal lines,type-I and type-III quadratic nodal points, and triply degenerate nodal points.

Piezocatalysis has emerged as a promising technology for environmental remediation by harnessing mechanical energy to drive redox reactions. In this study, Sm2O3-doped (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 (BCZT) solid solutions have been synthesized via a facile solid-state reaction to systematically investigate the effects of Sm3+ doping on the phase structure, defect chemistry, and piezocatalytic activity. Rietveld refinement, transmission electron microscopy, and Raman spectroscopy all confirm the coexistence of rhombohedral, orthorhombic, and tetragonal phases. The morphotropic phase boundary (MPB) promotes polarization rotation and enhances the piezoelectric response. The thermally stimulated depolarization current (TSDC) measurements reveal that the lowest defect (particularly oxygen vacancy) density is found in the BCZT samples doped with 0.02 wt % Sm2O3, which enable the materials to possess exceptional piezocatalytic performance, yielding a high degradation efficiency (96.8%) of rhodamine B within 30 min at a rate constant of 0.1156 min-1. Carrier separation and migration capabilities have been boosted through electrochemical and band structure analyses. This work indicates that Sm2O3 doping introduces local structural heterogeneity and optimizes the defect state for the host materials, providing an effective strategy for designing high-performance eco-friendly piezocatalysts.

Mitochondria play a crucial role in cellular bioenergetics, signaling, and metabolism; yet, many fundamental mechanisms such as the proton transfer along the membranes, the link between membrane curvature and oxidative phosphorylation, and the nanoscale organization of enzyme supercomplexes remain poorly understood due to the limitations of classical biochemical approaches. This review addresses this gap by systematically analyzing the contemporary physical methods used to investigate the mitochondrial structure and function from the micro to nano scale. It covers advanced fluorescence and super-resolution microscopy, electron and volume electron microscopy, and scanning probe techniques, as well as cryo-electron tomography for resolving supramolecular assemblies in near-native conditions. The review highlights the applications of the modern fluorescent probes, expansion and phase microscopy, and machine-learning-based image analysis for a quantitative assessment of the mitochondrial morphology, membrane potential, and dynamics in living cells and tissues. Complementary spectroscopic and scattering methods, including Raman spectroscopy, NMR, and X-ray and neutron scattering, are discussed as tools for probing the redox state, metabolite composition, and membrane organization. Emphasis is placed on integrating high-resolution experimental data with advanced computational frameworks to test competing models of mitochondrial function and pathology, and to guide the development of biomimetic and biomedical technologies.

The thermal behavior of 2D materials is dominated by interfaces, but very few methods exist to probe such atomically sharp interfaces. This study uses Raman Spectroscopy to explore the thermal-induced strain at the interfaces between graphene and hexagonal boron nitride. By analyzing shifts in Raman peaks under varying excitation power and temperature, we demonstrate the interplay between strain and thermal behavior, particularly the influence of temperature-induced strain on the Raman peak position of graphene. Our study underscores the critical role of thermal expansion in governing interfacial behavior, which is also sensitive to the nature of the interface. Our study offers new insights into how Raman spectroscopy can be utilized to quantify the strain developed between various interfaces, and our findings pave the way for advancing the understanding of heat transfer mechanisms in next-generation nanodevices.