Search Results (394)

Two novel multi-layer three-dimensional polymers (Polymer 1 and Polymer 2) were designed and synthesized via a multi-step coupling strategy. Their photophysical properties, aggregation-induced emission (AIE) behaviors, and metal ion sensing capabilities were systematically investigated. Both polymers exhibited typical aggregation-induced emission (AIE) characteristics with significantly enhanced fluorescence upon aggregation in tetrahydrofuran (THF)/water mixtures. Polymer 1 demonstrated selective and sensitive detection of Ag⁺ ions with a detection limit of 2.14 μM, while Polymer 2 showed exceptional recognition toward Ba²⁺ ions with a detection limit of 6.42 μM. Competitive experiments confirmed their good selectivity even in the presence of interfering metal ions. The distinct sensing behaviors were attributed to the different coordination environments provided by the polymer backbones. This work expands the family of multi-layer three-dimensional AIE-active polymers and demonstrates their utility as fluorescent probes for the detection of silver and barium ions. Full article

Lignin-derived carbon dots (CDs) are promising sustainable fluorescent nanomaterials for environmental sensing, yet precise regulation of their emission behavior and ion-recognition selectivity remains challenging. Herein, a solvent-free precursor–structure–engineering strategy was developed to prepare lignin-derived CDs with tunable photoluminescence and selective metal-ion sensing. Industrial alkali lignin, lysine, and oxalic acid were used as the carbon source, nitrogen source, and carbonization promoter, respectively, while cysteine, histidine, and p-phenylenediamine were introduced as functional precursors. The resulting C-CDs, H-CDs, and P-CDs showed distinct optical and sensing properties. H-CDs exhibited the highest photoluminescence quantum yield of 50.98%, attributed to enhanced graphitic nitrogen formation and electronic conjugation. P-CDs displayed a red-shifted emission at approximately 573 nm due to extended π-conjugated domains. Moreover, C-CDs, H-CDs, and P-CDs showed preferential fluorescence responses toward Fe³⁺, Cu²⁺, and Ag⁺, with detection limits of 0.26, 0.05, and 0.11 μM, respectively. The quenching behavior was inconsistent with a dominant dynamic collisional process and was instead associated primarily with metal–surface interactions. This work clarifies the precursor–structure–property relationship and provides a sustainable route for designing lignin-derived fluorescent probes. 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

This study investigated the effect of magnetic coupling of Fe³⁺ on Ho³⁺ luminescence in the double perovskite Cs₂NaScCl₆. Under 980 nm laser excitation, red emission from Ho³⁺ ions was observed in Cs₂NaScCl₆:Ho³⁺/Fe³⁺ samples. We propose that this arises from spin-selective up-conversion mediated by magnetic polarons (EMPs). However, green emission from the ⁵F₄/⁵S₂ levels was not observed in this system. The experimental results suggest that localized EMPs form via ferromagnetic short-range ordering between Fe³⁺ and Ho³⁺ or among Fe³⁺ ions. These EMPs can be directly excited to higher energy levels via a biexciton absorption transition, then relaxed to the ⁵F₅ level of Ho³⁺ through ferromagnetic coupling. Under X-ray excitation, the characteristic emission peaks of Ho³⁺ in Cs₂NaScCl₆:Ho³⁺/Fe³⁺ become smoother, lose fine structure, and significantly decrease in intensity with increasing Fe³⁺ concentration. Based on this, we prepared Fe³⁺-free Cs₂NaScCl₆:Ho³⁺ and explored its excellent scintillation performance, with a detection limit as low as 37.73 nGy_air s⁻¹, below the medical diagnostic dose, surpassing the performance of commercial scintillators such as LuAG:Ce and BGO. This work reports the phenomenon of using Fe³⁺ as a sensitizer to achieve up-conversion sensitization in chloride double perovskites and demonstrates the application potential of Fe-free systems in ultra-low-dose X-ray imaging. Full article

Battery engineers often work with repeated cycle-level monitoring signals that are related to ageing but are not direct capacity or resistance measurements. This paper studies how such a signal can be used to detect faster change and to decide whether the measured record is long enough to locate the transition reliably. We analyse 14 lithium-ion cell records from a processed Hawaii Natural Energy Institute (HNEI) cycle-level table, using the charging-to-discharge duration ratio (C/D) as a practical charge/discharge-duration indicator. The corresponding original HNEI measurement files were checked to improve the cell description and to examine whether a capacity-based comparison was possible. They confirm substantial capacity fade, but they also contain non-physical capacity entries near cycle 370; these entries are not used as validation of C/D transition cycles. We compare a linear reference, broken-line regression, a smoothing-spline curvature check, an aggregate Bayesian smooth-transition model, and a battery-level hierarchical Bayesian model. The hierarchical model estimates a mean battery-level transition cycle of 553.9 cycles (95% credible interval: 547.1–560.9), with substantial battery-to-battery variation (standard deviation about 142 cycles). All 14 batteries show a positive increase in the rate of change of C/D. Randomly removing about half of the measurements while retaining the full test span widens uncertainty but preserves the acceleration conclusion and nearly preserves battery ordering. In contrast, cutting off the late part of the test record strongly destabilizes transition timing and extrapolation. The approach is therefore useful as a retrospective screening and test-interpretation tool for a chosen ageing-related signal. It is not a direct capacity-knee detector, a mechanism diagnosis, or a remaining-useful-life predictor. Full article

Accurate discrimination of multiple heavy metal ions is essential for environmental monitoring. This study developed a simple fluorescent sensing array utilizing carbon dots derived from black plum peels (PCDs) for the precise identification of metal ions in environmental waters. Three structurally distinct PCDs were hydrothermally synthesized using phenylenediamine isomers as nitrogen dopants, exhibiting distinct fluorescence response patterns to target ions. Pattern recognition was performed using linear discriminant analysis (LDA) and hierarchical clustering analysis (HCA). The optimized system (pH 5–7) achieved high discrimination accuracy for eight metal ions (Sn²⁺, Ag⁺, Hg²⁺, Fe³⁺, Cr³⁺, Pb²⁺, Sb³⁺, and Cu²⁺) at 5–400 μM concentrations. The array effectively identified the binary and ternary mixtures of Hg²⁺/Cu²⁺/Cr³⁺ and successfully detected target ions in river water samples. This cost-effective and scalable approach demonstrates strong potential for applications in water quality monitoring and food safety. Full article

Background: Oxidative stress plays a key role in the pathogenesis of complications in preterm infants, including bronchopulmonary dysplasia (BPD). Thymosin β4 (Tβ4) and thymosin β10 (Tβ10) are proteins involved in tissue repair and responses to oxidative stress, but their role in extremely preterm neonates remains poorly understood. Methods: A total of 149 saliva samples from 18 infants with gestational age < 30 weeks were analyzed. Salivary proteins and their proteoforms were characterized using an integrated proteomic platform based on nano-HPLC-ESI-MS. Relative quantification was performed using extracted ion current (XIC) peak areas. Associations with postmenstrual age, oxygen requirement, and BPD development were assessed, including longitudinal analysis using generalized estimating equation (GEE) models. Results: Significant correlations were found between postmenstrual age and total Tβ4 (p = 0.001), oxidized Tβ4 percentage (p = 0.025), and total Tβ10 (p = 0.043). Higher oxygen requirement was associated with lower levels and percentages of oxidized Tβ10 (p = 0.005; p < 0.001). No significant differences were observed during the first week of life between neonates who later developed BPD and those who did not. However, longitudinal analysis showed that in neonates without BPD, total and oxidized Tβ10 and total Tβ4 increased over time, whereas in neonates with BPD, these biomarkers remained stable or decreased. The increase in oxidized Tβ10 percentage was slower in infants with BPD. Conclusions: Although no early differences were detected, longitudinal trajectories of Tβ4 and Tβ10 differed between infants with and without BPD. Postnatal changes in these proteins may be associated with differences in clinical course and exposure to postnatal oxidative stress. Full article

Radiation detection technology is critical in medical diagnosis, high-energy physics experiments, nuclear environmental monitoring, and radiation safety protection. Its technological iteration stems from innovations in high-performance radiation detection materials. Traditional materials often have narrow dose–response intervals, insufficient high-precision measurement capability, low spatial resolution, and poor stability, failing to meet high-precision detection requirements. Ag-doped phosphate glass (Ag-PG), based on radio-photoluminescence (RPL), effectively addresses these limitations with its comprehensive advantages: high radiation sensitivity, a wide linear dose–response range, submicron spatial resolution for radiation imaging, write-erase-rewrite capability, and visualized dose monitoring potential, and it also boasts significant fundamental research value and engineering application prospects. Specifically, while existing RPL reviews mainly provide a comprehensive analysis from the perspective of RPL and present typical RPL material systems, this paper systematically analyzes the structural characteristics of the Ag-PG matrix and the coordination configuration and site occupation of Ag ions. It clarifies RPL luminescence properties, dose–response mechanisms, and the evolution of luminescence centers, while reviewing advancements in applications such as radiation dose detection and high-resolution X-ray imaging. By summarizing the current research status, technical advantages and existing challenges of Ag-PG, this study provides theoretical references and conceptual insights to promote breakthroughs in its fundamental research and practical applications in high-precision radiation dose detection, advanced medical imaging, micro-nano-scale radiation detection, and nuclear industry non-destructive testing. Full article

Metallic contamination is a critical manufacturing defect in lithium-ion batteries, but the degradation evolution and electrochemical signatures of Cu-contaminated cells remain insufficiently understood. In this study, Cu particles were intentionally introduced into graphite/NCM811 pouch cells to investigate Cu-induced internal short circuit, cycling degradation, and defect detection. The Cu-contaminated cells exhibit significantly higher initial self-discharge rates, indicating the formation of a cathode-to-anode type internal short circuit. X-ray microscopy and SEM/EDS characterization reveal local separator penetration, electrode deformation, Cu dissolution/migration/deposition, Al current collector dissolution, and deposit accumulation on the anode surface. After cycling, the Cu-contaminated cells showed accelerated capacity fade and increased direct current internal resistance, while their self-discharge rate gradually decreased, suggesting partial mitigation of the internal short circuit path. Incremental capacity analysis was used to evaluate the internal short circuit severity, while differential voltage analysis was further applied to distinguish a Cu-induced internal short circuit from normal aging. This work provides mechanistic insight into Cu-contamination-induced degradation and electrochemical signatures for identifying metallic-contamination defects in lithium-ion cells. Full article

Copper is an indispensable trace element for maintaining metabolic homeostasis; however, the dysregulation and subsequent accumulation of Cu²⁺ are critically linked to neurodegenerative pathologies, including Alzheimer’s disease in humans. Consequently, the development of robust analytical tools for Cu²⁺ monitoring is of paramount importance. Here, we report a 2,2′-dipicolylamine porphyrin (DPAP)-based fluorescent sensor designed for the precise detection of metal cations. Photophysical investigations reveal that DPAP operates via a rapid turn-off fluorescence mechanism, achieving high-performance sensing in the parts-per-million range. Notably, the probe demonstrates exceptional sensitivity with detection limits of 26.3 nM for Cu²⁺ and 34.8 nM for Ni²⁺. Interference studies demonstrated the selectivity of DPAP for Cu²⁺ over a diverse range of competing metal ions such as Na⁺, Ag⁺, Ni²⁺, Cr³⁺, Pb²⁺, Al³⁺, Fe²⁺, Cd²⁺, and Zn²⁺. These results indicate that DPAP is a sensitive and selective probe suitable for copper ion detection. Full article

The literature collected from various search engines and high-quality scientific databases reveals that amino acid (AA)-functionalized nanoparticles have emerged as a promising field for selective detection and remediation of heavy metals (HMs). Among the various nanoparticles (NPs), gold nanoparticles (AuNPs) and silver nanoparticles (AgNPs) have drawn considerable attention, attributed to their unique optical, catalytic, and surface plasmon resonance properties. Functionalization with amino acids significantly enhances nanoparticle stability, biocompatibility, and metal-binding affinity through diverse functional groups. AA-functionalized AuNPs, including glycine, cystine, leucine, methionine, tyrosine, aspartic acid, histidine, and lysine-capped systems, exhibit tunable selectivity toward heavy metal ions. Bifunctionalization strategies further enhance sensitivity by inducing nanoparticle aggregation or signal amplification. Beyond single amino acids, polypeptides and protein-functionalized AuNPs offer enhanced molecular recognition and multivalent binding, expanding their applicability in complex matrices. Similarly, amino acid-functionalized AgNPs, such as those capped with similar amino acids stated above, exhibit strong interactions with heavy metals, AA bifunctionalization, and bimetallic nanoparticles (BNPs), particularly amino acid-functionalized Au–Ag systems, which combine the advantages of both metals, leading to improved sensitivity, selectivity, and signal strength. Although these advances have been made, a major gap remains in the systematic comparison of different amino acids, peptides, and bimetallic systems under real-world conditions. This gap can be addressed by standardized testing methods, clearer structure–function relationships and combined experimentation to guide the rational design of more efficient AA-functionalized nanoparticles. Full article

Heavy metal ions are common environmental contaminants that threaten aquatic ecosystems and human health. However, conventional analytical techniques often require expensive instrumentation and complex sample pretreatment. This work presents a peptide-based multichannel solid-state potentiometric microelectrode array for simultaneous detection of Cu²⁺, Cd²⁺, and Pb²⁺. The array consists of one shared Ag/AgCl reference electrode and three groups of gold indicator microelectrodes (10 μm in diameter), with each group containing three parallel electrodes for replicate measurements. Each group is functionalized with a distinct peptide receptor specific to one target metal ion. The proposed array exhibits near-Nernstian responses and good selectivity against common interfering ions. Practical applicability is demonstrated by analyzing spiked lake water samples under a fixed chloride condition, with recoveries ranging from 94% to 105%. This work provides a miniaturized, reproducible, and versatile platform for simultaneous potentiometric detection of multiple heavy metal ions, and the peptide-based recognition strategy can be extended to other targets by simply replacing the peptide sequences. Full article

Background: Metallic and metal oxide nanoparticles are increasingly explored as antimicrobial biomaterials in endodontics due to their multi-target mechanisms of action, largely mediated by metal ion release (e.g., Ag⁺, Cu⁺). However, bacterial metal resistance systems, particularly efflux-related proteins, may influence their antimicrobial performance. This study aimed to analyze the prevalence and distribution of metal resistance-associated proteins in bacteria involved in endodontic infections using a bioinformatic approach. Methods: An in silico, cross-sectional bioinformatic analysis was conducted using publicly available genomes from the Bacterial and Viral Bioinformatics Resource Center (BV-BRC). Bacterial species associated with acute apical abscess (AAA), symptomatic apical periodontitis (SAP), asymptomatic apical periodontitis (AAP), and post-treatment apical periodontitis (PTAP) were included. The presence of selected metal resistance-related proteins (CutC, CopA, CzcA, CusA, SilA, P-type ATPase, and PA3920) was assessed using a binary presence/absence framework. Prevalence, group comparisons (Fisher’s exact test), and co-occurrence patterns (Phi coefficient) were analyzed. Results: Metal resistance-associated proteins were widely distributed across all infection types, with prevalence ranging from 70.0% to 82.9% and no significant differences between groups (p > 0.05). CutC was the most prevalent protein, followed by CopA and CzcA, whereas SilA and PA3920 were not detected. Correlation analysis revealed consistent co-occurrence patterns among key taxa, including Porphyromonas gingivalis, Fusobacterium nucleatum, and Prevotella spp. Conclusions: Metal resistance-related proteins are broadly distributed in endodontic microbiota, indicating a conserved genetic capacity for metal tolerance. These findings suggest that microbial resistance determinants may influence, but do not directly determine, the antimicrobial performance of nanoparticle-based biomaterials. This study provides a hypothesis-generating, bioinformatic framework to support the design and optimization of antimicrobial biomaterials, highlighting the need for experimental validation and integration of phenotypic and biofilm-based analyses. Full article

To clarify the control mechanism of water quality parameters on metal particle release from pipe scales in aging ductile iron water supply pipelines (service life > 20 years), this study conducted single-factor experiments to explore the effects of pH, temperature, concentration of humic acid (HA) and Mn²⁺ on Fe, Mn, and Al particle release. Combined with inductively coupled plasma optical emission spectrometry (ICP-OES) for quantitative detection, first-order/second-order kinetic fitting, and X-ray diffraction (XRD) and scanning electron microscopy-energy dispersive spectrometry (SEM-EDS) characterization, the results showed that an increase in temperature generally promoted the aggregation and sedimentation of metal particles, among which Fe and Mn particles were more sensitive to temperature changes. pH affected the sedimentation process by controlling metal ion speciation and particle surface charge: low pH significantly accelerated pipe scale dissolution, while weakly alkaline conditions prolonged particle suspension time. Low-concentration HA (0.5 mg/L) promoted particle dissolution, whereas high-concentration HA (1.0–2.0 mg/L) extended particle retention time through surface coating. Mn²⁺ concentration exhibited an obvious concentration-dependent effect: the range of 20–50 μg/L enhanced particle suspension stability, while 80–100 μg/L accelerated particle aggregation and sedimentation. The pipe scales mainly consisted of Fe₃O₄, Fe₂O₃, Mn₃O₄, and Al₂O₃, with metal release regulated by the “element complexation–particle aggregation–crystal growth” pathway. Particle sedimentation followed first-order kinetics. Controlling pH at 7.0, temperature < 30 °C, and reducing HA/Mn²⁺ concentrations effectively weakened metal particle migration. This study reveals the coupled effect mechanism of water quality parameters, providing theoretical and technical support for optimizing water quality control and solving the “yellow water” problem. Full article

To address the inherent low voltage and poor energy density of LiFePO₄, LiFe_0.6Mn_0.4PO₄ (LFMP) has emerged as a promising cathode for next-generation lithium-ion batteries. However, its practical application is severely hindered by intrinsic limitations such as low electronic conductivity and sluggish Li⁺ diffusion. To address these challenges, this study investigates the effects of silver (Ag) doping on the structural and electrochemical performance of LFMP. Through a facile high-temperature solid-state approach, Ag⁺ ions are successfully incorporated into the LFMP matrix, and the resulting material (LFMP-Ag) is systematically characterized. The results reveal that partial Ag is doped into the LFMP lattice while an Ag-rich secondary phase within LFMP particles is detected, significantly enhancing the charge transfer kinetics. The Ag-doped LFMP cathodes exhibit superior discharge capacity of 142.1 mAh g⁻¹ at 0.1 C, enhanced rate capability, better cyclic stability (92.3% retention after 300 cycles) and enhanced thermal stability, surpassing the undoped LFMP counterparts. These findings demonstrate that Ag doping is an effective strategy for optimizing the electrochemical performance of LFMP cathodes, offering a viable pathway toward advanced battery technologies. Full article