Search Results (414)

This paper reports the effects of formed perfluoroalkylsilane self-assembled monolayers (SAMs) on the tribological and corrosion properties of TiO_x-incorporated diamond-like carbon (TiO_x-DLC) coatings deposited on a Ti6Al4V substrate. The SAMs were formed using 1H,1H,2H,2H -perfluorodecyltrichlorosilane (FDTS) and (3,3,3 -trifluoropropyl) trichlorosilane (FPTS) compounds. Their presence was confirmed using techniques such as ellipsometry, time-of-flight secondary ion mass spectrometry, and Fourier-transform infrared spectroscopy. The results of the ball-on-disc test indicate the role of the structure of the created SAMs on their tribological properties. The FDTS compounds with longer alkyl chains favor the creation of a well-packed layer bonded to the TiO_x-DLC coating. This hydrophobic structure allows for obtaining the lowest coefficient of friction (0.180) during tribological tests. The results of electrochemical tests indicate that the SAM modification reduces the barrier properties of TiO_x-DLC and provides enhanced kinetic stability against carbon matrix oxidation at higher anodic potentials. Full article

Solid electrolyte interphase (SEI) characterization is needed to interpret the performance, degradation, and lifetime of graphite and Si-containing carbon-based negative electrodes in lithium-ion batteries. However, SEI claims are often difficult to compare because measured signals, inferred assignments, sample history, and electrode architecture are not always clearly separated. This review presents a claim-bounded framework for SEI characterization that distinguishes direct observables from inferred chemical, molecular, structural, morphological, and functional information. Photoelectron spectroscopy methods provide chemical-state and relative-depth-sensitivity constraints; secondary-ion mass spectrometry methods provide fragment and isotope distributions; vibrational spectroscopies support functional-group and local vibrational evidence; nuclear magnetic resonance and molecular mass spectrometry provide molecular or product-level constraints; and microscopy, tomography, and atomic force microscopy provide morphology, architecture, local thickness, topography, and mechanical response. Across these methods, rinsing, drying, sputtering, beam exposure, extraction, and limited sampling can alter the observable and therefore the defensible claim. The review emphasizes the distinction between native electrode-associated SEI features and extracted, soluble, or electrolyte-phase products, and between morphology-only evidence and chemically assigned morphology. It concludes by proposing claim-driven correlative workflows and reporting guidance for reproducible interpretation on graphite, Si/graphite, Si/C, and carbon-coated Si architectures where directly studied or present. Full article

Brassica crops, encompassing globally important vegetables and oilseeds, face severe threats from diverse biotic and abiotic stresses. Plant secondary metabolites constitute the chemical foundation of defence, and metabolomics has emerged as an effective systems biology tool for comprehensively dissecting stress-induced metabolic changes. Recent progress in applying metabolomics to elucidate defence mechanisms in Brassica crops is systematically synthesised here. Major stresses confronting Brassica crop production and the metabolic basis of plant defence are first outlined. Current analytical platforms, including liquid chromatography–mass spectrometry, gas chromatography–mass spectrometry, ion mobility spectrometry, and mass spectrometry imaging, are critically evaluated alongside data processing workflows and multi-omics integration strategies. Key defence-related metabolite classes identified in Brassica crops, notably glucosinolates (GSLs) and their hydrolysis products, phenolic compounds, and lipid-derived signalling molecules, are surveyed with emphasis on their respective functions in biotic and abiotic stress responses. Metabolomics has been instrumental in revealing distinct metabolic reprogramming patterns triggered by diverse stresses, including pathogen infection, insect herbivory, drought, salinity, temperature extremes, and heavy metal stress. Metabolomics-informed crop improvement strategies, including marker-assisted breeding, genetic and metabolic engineering, and precision agronomic practices, are discussed together with current technical bottlenecks and future directions involving artificial intelligence, metabolic modelling, and spatial metabolomics. The compiled knowledge provides a comprehensive reference for leveraging metabolomics to enhance stress resilience and sustainable production of Brassica crops. Full article

This study used time-of-flight secondary ion mass spectrometry (TOF-SIMS) to comprehensively analyze the elemental composition, ion distribution, and signal variations in potassium dihydrogen phosphate (KDP) crystals at various sputtering depths after laser irradiation. Positive ion mass spectra were employed to identify the characteristic ions K⁺, Ca⁺, Fe⁺, Si⁺, and P⁺. These ions were assigned to their corresponding chemical species. Large-area two-dimensional chemical mapping and maximum count/total count (MC/TC) analysis combined and showed clear depth-dependent trends; all detected ions had significantly higher MC and TC values at larger sputtering depths. At a depth of 1.3 nm, Fe-related and O-related ion signals exhibited overlapping localized hotspots, whereas Ca species showed ring-like enrichment at the edges of the damage pits. These changes are attributed to the laser-induced decomposition of KDP crystals, in which metal inclusions absorb laser energy, generate localized high temperature and pressure, and promote material ejection and ion redistribution. These findings provide direct experimental evidence for understanding laser-induced elemental redistribution in KDP crystals and offer useful guidance for further optimization of their performance. Full article

We demonstrate that dopant inhomogeneity strongly suppresses thermal conductivity in Cd/Eu co-doped, non-polar a-plane-oriented ZnO films grown on r-plane sapphire (Al₂O₃) by plasma-assisted molecular beam epitaxy. X-ray diffraction confirms the a-plane-oriented ZnO without detectable secondary phases. Cross-sectional scanning electron microscopy shows continuous films with well-defined interfaces, and secondary-ion mass spectrometry depth profiling identifies Cd/Eu incorporation through the film thickness and a sharp Zn/O drop at the substrate interface. Cross-plane thermal transport was measured at room temperature using frequency-domain photothermal infrared radiometry (PTR) and analyzed by fitting the complex PTR amplitude and phase with a multilayer heat-diffusion model. The extracted thermal conductivity ($\kappa$) spans ~3.7–6.3 W·m⁻¹·K⁻¹. The lowest $\kappa$ values correlate with increased Eu-distribution inhomogeneity, consistent with enhanced phonon scattering and reduced effective cross-plane heat transport. Full article

Volatile fingerprints provide useful information for characterizing Astragali Radix (AR), a food–medicine homologous plant material, but differences among wild, wild-simulated, and cultivated samples remain unclear. In this study, headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry (HS-SPME-GC–MS) and headspace gas chromatography–ion mobility spectrometry (HS-GC–IMS) were integrated with multivariate analysis and interpretable machine learning to characterize volatile profiles and identify candidate discriminatory compounds in 117 AR samples from different cultivation patterns. HS-SPME-GC–MS tentatively identified 29, 34, and 45 volatile compounds in wild, wild-simulated, and cultivated samples, respectively. Esters were the predominant class in all groups, although the relative abundance of esters and the overall chemical-class composition varied among cultivation patterns. HS-GC–IMS tentatively identified 57, 50, and 55 compounds, respectively, comprising mainly low-molecular-weight aldehydes, alcohols, and ketones and thereby providing complementary volatile fingerprint information. Partial least squares discriminant analysis (PLS-DA) showed that the volatile fingerprints captured cultivation-pattern-associated differences, with the HS-GC–IMS model showing clearer group separation. Random forest, support vector machine, and CatBoost models were further constructed using the HS-SPME-GC–MS profiling results. By integrating variable importance in projection (VIP) and SHapley Additive exPlanations (SHAP) values, γ-hexalactone, methyl eugenol, methyl (9Z,11E)-octadeca-9,11-dienoate, eugenol, and ethyl linoleate were selected as candidate discriminatory compounds. Based on the HS-GC–IMS results, 1-octen-3-one, pentyl acetate, (Z)-2-penten-1-ol, 2-heptanone, and the monomeric signal of 2-ethyl-6-methylpyrazine were also identified as candidate discriminatory compounds. These compounds may be related to fatty acid-derived metabolism, aromatic secondary metabolism, and terpenoid-related processes. The integration of two complementary volatile-analysis platforms with VIP- and SHAP-based interpretation provided broader coverage of volatile features and improved the interpretability of candidate-compound screening. These findings provide an interpretable analytical workflow and candidate discriminatory compounds that may support future rapid screening, cultivation-pattern authentication, and volatile-profile-based differentiation of AR, pending independent external validation. Full article

Detection of nanoplastics in drinking-water systems is only the first analytical step toward exposure interpretation; the next challenge is source attribution. This review examines molecular fingerprinting and transformation pathways that can link nanoscale polymer signals to source waters, drinking-water treatment, distribution infrastructure, packaging materials, laboratory background, or aging processes across the potable-water chain. Nanoplastics are treated here as operationally defined particles below 1 µm, including intentionally manufactured primary nanoplastics and secondary nanoplastics generated by fragmentation, abrasion, weathering, treatment, storage, or packaging stress. The synthesis evaluates how polymer identity, particle morphology, surface oxidation, additive and oligomer profiles, thermal degradation markers, matrix context, and quality assurance/quality control (QA/QC) can be combined into defensible source assignments. Analytical platforms considered include surface-enhanced Raman spectroscopy (SERS), atomic force microscopy–infrared spectroscopy (AFM-IR), optical photothermal infrared spectroscopy (O-PTIR), stimulated Raman scattering microscopy (SRS), pyrolysis–gas chromatography–mass spectrometry (Py-GC/MS), asymmetric flow field-flow fractionation coupled to Py-GC/MS (AF4-Py-GC/MS), matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS), and chemometric workflows. The central conclusion is that source attribution cannot be inferred from polymer identity alone; robust interpretation requires convergent evidence from particle-level chemistry, polymer-specific mass, additive or marker-ion signatures, aging state, blanks, recovery, and contextual sampling design. Full article

Background/Objectives: Marine microorganism metabolites are structurally unique secondary metabolites possessing therapeutic potential. The current study aims to identify a novel ATPase regulator using a newly established bidirectional activity evaluation system to screen for microbial metabolites that inhibit the activities of Na⁺-K⁺-ATPase or Ca²⁺-Mg²⁺-ATPase. Methods: A total of 1258 marine microbial strains were isolated from sea mud in Zhoushan, Zhejiang. Results: The extract of strain ZSDH2536 exhibited Na⁺-K⁺ and Ca²⁺-Mg²⁺-ATPase inhibitory activity and was identified as Sirastachys pandanicola based on morphological and molecular phylogenetic analyses. The secondary metabolite was tentatively identified in the ZSDH2536 strain as a bisindole compound, and named Pandanicoline based on ¹H-NMR, ¹³C-NMR and high-resolution mass spectrometry analysis. The chemical formula of Pandanicoline is C₅₁H₆₈N₂O₁₀, with an isotopic mass of 868.4874 Da. The maximum inhibition rate of Pandanicoline on Na⁺-K⁺ and Ca²⁺-Mg²⁺-ATPase was 36.37% and 37.27%, respectively. Moreover, in silico analysis also showed the binding energy of Pandanicoline with Na⁺-K⁺-ATPase was −9.124 kcal/mol and with the Ca²⁺-Mg²⁺-ATPase complex was −10.47 kcal/mol. Conclusions: The strain ZSDH2536 represents a promising source of dual inhibitors targeting Na⁺-K⁺ and Ca²⁺-Mg²⁺-ATPase. Pandanicoline exhibits potential as a lead compound for regulating ion homeostasis, providing new opportunities for further investigation into its mechanism and therapeutic applications. Full article

Peak annotation in Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) is a persistent bottleneck that typically requires the manual assignment of chemical formulas to hundreds of fragment ion peaks per spectrum. This work describes a physics-informed probabilistic framework that automates this task by combining five chemically motivated constraints—Gaussian mass accuracy, element composition priors, isotope pattern matching, nitrogen rule parity, and graded valence bounds—into a multiplicative belief score. We evaluate the framework on 643 ground-truth peaks from 151 compounds spanning both positive and negative ion modes, and we explicitly distinguish two regimes. As a scoring task—when the correct formula is present in the candidate list—the framework attains 52.3% Top-1 and 76.4% Top-3 accuracy, a 4.9-fold improvement over mass-only scoring. In fully automated end-to-end deployment, where candidates are generated de novo, Top-1 accuracy is 26.3%; the limiting factor is candidate generation rather than scoring, as only 46.5% of ground-truth formulas are currently produced by the database and combinatorial generator. Leave-One-Compound-Out Cross-Validation (59 compounds, 525 peaks) yields 51.8% Top-1 accuracy with fixed domain-knowledge weights, confirming generalization stability. Ablation analysis identifies element composition priors as the dominant non-mass constraint (−27.7 percentage points when removed), followed by isotope matching (−10.3 pp) and the nitrogen rule (−5.3 pp). The framework requires no labeled training spectra—relying instead on physically motivated priors and curated fragment databases—provides interpretable per-constraint scores (which represent relative rankings rather than calibrated probabilities), and supports polarity-specific configurations, offering a practical computational foundation for automated ToF-SIMS spectrum interpretation. Full article

Objectives: This study aimed to employ a High Performance Liquid Chromatography coupled with Quadrupole Time-of-Flight Mass Spectrometry(HPLC-QTOF/MS) system to detect potential metabolites of 2-Fluorodeschloroketamine (2-FDCK) and 2-fluoro-N-ethylketamine (2-FXE) in rats, elucidate their metabolic pathways, and analyze the metabolic differences between the two compounds. Such exploration is vital for understanding their distinct drug effects and providing a reference for forensic toxicological assessment of new phencyclidine-class psychoactive substances. Methods: Twelve SD rats were randomly split into two groups. After a 12 h fast, each group was administered a single intraperitoneal injection of one drug at 0.045 mg/kg. At 1 h and 2 h post-dosing, the rats were euthanized, and blood, liver tissue, and urine samples were promptly collected. These samples underwent rapid solvent extraction for pretreatment and were then analyzed using HPLC-QTOF. Metabolites were identified through database searches and secondary mass spectrometry fragment ion analysis. Results: Comparative analysis of metabolite types, formation times, and chromatographic peak response intensities between the two groups showed that metabolic pathways were mostly consistent. However, significant differences were observed in metabolic reaction types, metabolite formation times, and response intensities, likely stemming from chemical structural disparities. Conclusions: The findings offer crucial insights into the drug effect differences between the two compounds and establish a valuable reference for forensic toxicological evaluation of new phencyclidine-class psychoactive substances. Full article

This study investigated the effects of different cultivation environments on melon quality development and the underlying metabolic regulatory mechanisms. Using ‘Yangjiaocui’ and ‘Boyang 9’ melons, we systematically compared their physicochemical properties, nutritional components, volatile compounds, and metabolites under saline–alkali versus normal conditions, employing an integrated multi-omics analytical model. The results showed that saline–alkali cultivation significantly increased several nutritional components (e.g., soluble solids, vitamin C, flavonoids, and polyphenols) compared to normal conditions. Gas chromatography–ion mobility spectrometry (GC-IMS) detected 36 volatiles, predominantly esters and ketones, with 13 key markers such as isovaleric acid isovaleryl ester and ethyl butyrate, effectively discriminating cultivars and growth origins. Liquid chromatography–mass spectrometry (LC-MS) detected 702 metabolites, chiefly organic acids and lipids. KEGG pathway enrichment analysis revealed that flavonoid biosynthesis was the most significantly enriched pathway (enrichment factor ~1, extreme significance), with coordinated regulation of tyrosine and phenylalanine metabolism redirecting metabolic flux toward defensive secondary metabolites. In conclusion, our results suggest that saline–alkali cultivation may contribute to improved nutritional profiles, and multi-omics analysis effectively differentiates melon varieties and origins. This study provides a theoretical basis for understanding the quality, flavor, and metabolite profiles of melon under saline–alkali stress, employing a multi-omics approach. Full article

In energy conversion semiconductor devices, radiation damage is directly related to the long-term stability of β-voltaic batteries. In this study, single-crystalline silicon P⁺NN⁺ devices and P⁺-silicon materials with SiO₂ surface passivation were irradiated using a ~70 keV accelerator electron beam in a nitrogen atmosphere for 2 min, 10 min, 1 h, 6 h, and 12 h. The tritium-voltaic output decreased rapidly within the first 2 min of electron beam irradiation and then decayed slowly. After 1 h of irradiation, both the output short-circuit current (Isc) and open-circuit voltage (Voc) remained stable. The effects of the damage were analyzed using typical samples irradiated for 1 h. Neutron reflectometry (NR) was employed as the primary characterization method, while X-ray photoelectron spectroscopy (XPS)—combined with Ar⁺ etching—and secondary ion mass spectrometry (SIMS) were used to verify radiation-induced structural changes at the SiO₂ surface and SiO₂/Si interface. It was found that nitrogen atoms from the atmosphere penetrated the SiO₂ layer to a depth of approximately 5–10 nm, forming a non-stoichiometric SiON structure, without further diffusion into deeper layers. Irradiation significantly increased the thickness of the SiO₂/Si interface transition layer to about 14–18.5 nm, and the SiO₂ structure within this layer became relatively loose. It can be inferred that tritium-voltaic batteries using SiO₂-surface-passivated single-crystalline silicon P⁺NN⁺ devices as energy-conversion units and packaged in a nitrogen atmosphere can stably provide power for 10 years, with an Isc reduction of no more than 12% and a Voc reduction of no more than 6%, excluding the spontaneous decay of tritium. Full article

Infrared photodetectors are important for military, medical, and environmental applications. Dual-color quantum well infrared photodetectors (QWIPs) are attractive because they can provide multi-spectral information, but their performance is often limited by high dark current. In this study, we designed and fabricated two dual-color QWIPs. Sample A exhibits rectification-like dark-current behavior, whereas Sample B shows a nearly symmetric current–voltage characteristic together with an approximately two-order-of-magnitude reduction in dark current under the same operating condition. By combining secondary ion mass spectrometry (SIMS), scanning spreading resistance microscopy (SSRM), energy-band simulations, and optoelectronic characterization, we show that Sample B exhibits a larger disparity in effective carrier distribution between the two quantum-well groups than Sample A. The experimental results and simulations consistently indicate that this disparity, together with the higher barrier design, is associated with a redistribution of the internal potential and a stronger voltage drop across the lightly doped region, which is consistent with reduced thermally activated carrier transport. Although the lower carrier concentration in the lightly doped wells is accompanied by reduced blackbody responsivity, the stronger suppression of dark current leads to a higher peak blackbody detectivity under identical blackbody-illumination conditions. At 50 K and −1.5 V, the peak blackbody detectivity of Sample B is approximately four times that of Sample A. These results support the conclusion that combining barrier-height design with controlled inter-group carrier disparity is an effective strategy for tuning carrier transport and improving the peak blackbody detectivity trade-off in dual-color QWIPs within the conditions examined here. Full article

Since its introduction, focused ion beam (FIB) technology has expanded from micro/nanofabrication in the semiconductor industry to the field of multimodal characterization of metallic material microstructures. This article systematically reviews the latest research advances in FIB-SEM technology in the field of metallic materials science. The fundamental principles and system functions of FIB-SEM are introduced, with an emphasis on its key applications in two-dimensional and three-dimensional morphological characterization, as well as specimen preparation for transmission electron microscopy (TEM) and atom probe tomography (APT). The combined strategies of FIB-SEM with electron backscatter diffraction (EBSD), time-of-flight secondary ion mass spectrometry (TOF-SIMS), and other characterization techniques are also discussed. Current developments indicate that FIB-SEM technology is advancing toward multi-ion-source synergy and multimodal integration. In the future, combined with artificial intelligence and big data analysis, it is expected to enable high-throughput, correlative measurements of multidimensional properties at the micro scale, providing important technical support for “materials genome” research in metallic materials. Full article

Biofouling is an issue of global significance that impairs marine infrastructure, causes increased fuel consumption and greenhouse gas emissions, and threatens biodiversity. Since the year 2000, self-polishing copolymer (SPC) coatings and fouling release coatings (FRCs) dominate the fouling protection coatings market. SPC technology is based on the controlled release of biocides using a mixture of acrylic and natural binders as a delivery system. FRC technology is based on PDMS providing surface properties that resist attachment of fouling organisms. FRCs often contain surface modifying agents, such as free silicone oils, to tune the physicochemical properties of the surface. However, the long-term efficacy of these agents and their migration and distribution in PDMS-based coatings have not been well studied. In this study, we employed time-of-flight secondary ion mass spectrometry (ToF-SIMS) combined with multivariate analysis to examine the distribution of silicone oils as a function of exposure to artificial seawater (ASW). The results show that pure PDMS-based coatings allow uniform distribution of silicone oils with robust behavior upon ASW exposure. In contrast, epoxy–PDMS-based coatings displayed phase separation of the oils, which strongly altered their surface chemistry. Our findings suggest that the modification of mobile oils is critical to the performance of marine antifouling coatings. Furthermore, the presence of other ingredients of commercial coating formulations strongly affected the distribution of mobile oils. This study lays the foundation for future systematic research aimed at developing predictive models to optimize fouling protection coatings for the marine industry. Full article