Search Results (434)

CeO₂ is widely studied in catalysis owing to its Ce⁴⁺/Ce³⁺ redox couple and oxygen storage capacity (OSC), but its low-temperature redox activity remains a challenge. To address this, this study investigates the effects of saturated In³⁺ doping (1 mol.%) on the structural, redox, and catalytic properties of nano-octahedral CeO₂. Structural and chemical analyses reveal that In³⁺ doping induces lattice contraction from 5.4171 to 5.4129 Å, increases oxygen vacancy concentration from 29.7% to 39.8%, and raises surface Ce³⁺ fraction from 27.6% to 30.0%. Consequently, H₂-TPR measurements show that the surface reduction peak temperature decreases from 548 to 406 °C and the onset reduction temperature shifts from 309 °C to 183 °C. Quantitative OSC analysis further demonstrates that the low-temperature OSC increases from 13.17 to 20.57 mmol O₂/mol and the high-temperature OSC from 53.36 to 59.38 mmol O₂/mol upon doping. As a result of these enhancements, CO-TPSR tests reveal improved low-temperature CO oxidation performance, with the CO₂ light-off temperature decreasing from 99 to 72 °C and the rapid oxidation temperature from 153 to 96 °C. Notably, H₂O and H₂ signals are detected during CO-TPSR, and FTIR analysis confirms the enrichment of surface hydroxyl groups in the doped sample, offering new mechanistic insights into the involvement of surface species in the reaction pathway. Overall, saturated In³⁺ doping effectively enhances the oxygen vacancy concentration, surface reducibility, and CO oxidation activity of nano-octahedral CeO₂. Full article

Layered sodium transition-metal oxides are promising cathode materials for sodium-ion batteries due to their high theoretical capacity; however, their practical application is often limited by sluggish Na⁺ diffusion kinetics and structural instability during cycling. P2/O3 phase coexistence has been proposed as an effective strategy to balance capacity and stability, yet it is typically achieved through precise Na-content tuning or complex synthesis conditions, which restrict compositional flexibility. Herein, we demonstrate a phase-engineering approach that induces stable P2/O3 phase coexistence without adjusting the overall Na stoichiometry by controlling the dopant incorporation pathway. Using Na_0.8(Ni_0.25Fe_0.33Mn_0.33Cu_0.07)O₂ (NaNFMC) as a model system, Mg doping via a wet chemical route enables homogeneous dopant distribution, which triggers local stacking rearrangement and the formation of prismatic Na⁺ diffusion channels characteristic of the P2 phase. In contrast, dry-doped samples with identical Mg content retain a predominantly O3-type structure, highlighting the decisive role of dopant incorporation in governing phase evolution. As a result of the phase-engineered P2/O3 coexisting framework, the Mg wet-doped cathode exhibits enhanced initial reversibility, superior rate capability, and improved long-term cycling stability compared to pristine and dry-doped counterparts. Voltage-resolved dQ/dV and cyclic voltammetry analyses reveal stabilized redox behavior with reduced polarization, while electrochemical impedance spectroscopy confirms suppressed impedance growth and improved Na⁺ transport kinetics after cycling. This study establishes that phase engineering through controlled dopant incorporation provides an effective alternative to conventional Na-content tuning strategies for layered sodium cathodes. The findings offer a scalable and versatile design principle for optimizing the electrochemical performance and structural durability of next-generation sodium-ion battery cathode materials. Full article

Blood glutathione (GSH), its oxidized form glutathione disulfide (GSSG), and especially the ratio of reduced to oxidized glutathione (GSH/GSSG) are recognized as robust biomarkers of oxidative stress. However, the broader application of these biomarkers has been limited by two major challenges: (1) the high risk of artifact formation during sample handling, which can artificially increase GSSG levels and bias redox balance measurements, and (2) the reliance on complex, instrument-intensive analytical procedures and the requirement for venous blood. We present an adaptation of the highly sensitive and easy-to-perform Tietze recycling method for microvolumes of blood. The challenge is to achieve accurate and precise measurements while avoiding artifacts, taking advantage of the high sensitivity of this enzymatic recycling analytical procedure. The method uses a simplified sample preparation protocol compatible with small blood volumes (up to 10 μL) and requires only basic laboratory equipment, such as a standard spectrophotometer or microplate reader. As this is an enzyme-based assay, we also carefully evaluate the main factors that can affect the measurements. This novel procedure provides a practical tool for monitoring GSH/GSSG as a biomarker of oxidative stress in various experimental settings by eliminating the need for trained personnel for blood sampling (it is suitable for capillary blood), minimizing discomfort for subjects, and avoiding complex procedures or instruments for analyte detection. Full article

Submarine volcanic-hosted iron oxide deposits are critical archives for reconstructing the interplay between hydrothermal activities and marine redox conditions, yet the genesis of these deposits remains controversial. Here, we present a comprehensive geochronological and geochemical study on the Shikebutai iron deposit in the Western Tianshan, northwestern China, to constrain the mineralization age, the source of iron, and deposit genesis. The stratiform-to-lenticular orebodies are hosted within the Late Carboniferous marine volcanic–sedimentary sequence of the Yishijilike Formation. The iron ores consist primarily of hematite and quartz, with minor siderite and barite, exhibiting massive to locally banded textures. SHRIMP zircon U-Pb dating of the overlying andesite yields an age of 315.8 ± 1.5 Ma, consistent with the Sm–Nd isochron age of the iron ore samples (319 ± 26 Ma), precisely constraining the mineralization age to the Late Carboniferous (ca. 315–320 Ma). The geochemical compositions of the iron ore samples indicate negligible syn-depositional detrital contamination, as evidenced by low Al₂O₃ (<1.00 wt%) and TiO₂ (<0.20 wt%) contents. Low abundances of trace elements, including Sr (0.33–31.18 ppm), Hf (0.05–1.77 ppm) and Rb (1.49–39.02 ppm), further support the minimal detrital influence. Geochemical signatures, such as pronounced positive Eu anomalies (Eu/Eu = 1.62–7.12, mean 4.14), LREE enrichment ((La/Yb) _(PAAS) = 0.58–4.78), and near-chondritic Y/Ho ratios (mean 28.5), suggest a significant high-temperature (>250 °C) hydrothermal contribution. Moreover, the ε_Nd(t) values of iron ore samples (+1.99 to +2.93) are comparable to those of coeval andesites (+2.75 to +3.44) but exceed those of associated metasiltstones (+0.41 to +0.95), suggesting that ore-forming materials were derived from hydrothermal fluids leaching juvenile crust. The Shikebutai iron deposit exhibits geochemical and mineralogical similarities to modern Red Sea and East Pacific Rise metalliferous sediments, establishing the deposit as a product of active vent-proximal hydrothermal systems rather than marine chemical sediments such as banded iron formations. Full article

Organophosphorus pesticide residues (OPPs) pose significant threats to ecological systems and human health, and conventional detection techniques are cumbersome, time-consuming, and costly. Herein, a facile electrochemical biosensor has been constructed based on a methyl green/chitosan (MG/Chi) composite membrane-modified electrode for the selective detection of OPPs, using isazofos (Isa) as the model analyte. Experimental results demonstrated that Isa significantly decreases the redox peak current of the modified electrode in buffer solution, and a good linear relationship was observed between the change in peak current and Isa concentration within a specific range. This biosensor exhibits excellent anti-interference capability and high sensitivity, with a limit of detection (LOD) as low as 0.60 μM. Furthermore, it was successfully applied for the quantitative determination of OPPs in real food and environmental samples, which confirms its reliable practical applicability and potential for on-site monitoring. Full article

An important challenge for materials researchers in the modern era is the fabrication of high-performance electrodes with novel designs and structures to enhance electrochemical sensing and energy storage performance. Recently, perovskite-structured bimetallic hydroxide materials, owing to their high conductivity, decent surface area, abundant redox activity, and good stability, have emerged as promising candidates for bifunctional electrochemical applications. In this study, we designed perovskite-type CuSn(OH)₆ microspheres via a facile coprecipitation method for nifedipine (NFD) sensing and supercapacitors (SCs). Various characterization techniques were employed to confirm the successful synthesis of CuSn(OH)₆. The uniform formation and distribution of CuSn(OH)₆ within the sphere structure provide rich reactive sites and enhance structural stability, thereby improving electrochemical activity. This architecture also induces a synergistic effect between Cu and Sn, which increases conductivity and accelerates redox kinetics. Consequently, the electrode modified with CuSn(OH)₆/GCE exhibited a wide linear concentration range of 0.4–303.3 µM and a low detection limit of 0.44 µM for NFD detection. This sensor further demonstrated superior analytical reliability, with selectivity of <5%, cycling stability of 84.79%, reproducibility of 3.3%, and recovery rates of 99.2–99.8% in the serum sample. Concurrently, the CuSn(OH)₆/NF showcased a high specific capacitance of 514 F g⁻¹ at 1 A g⁻¹, good longevity of 83.05% retention after 5000 cycles, and low charge transfer resistance of 6.56 Ω and solution resistance of 1.04 Ω, validating fast ion–electron transport. These results underscore that perovskite-based CuSn(OH)₆ is an efficient dual-functional electrocatalyst for sensitive electrochemical detection and high-performance SCs. Full article

Head and neck squamous cell carcinoma (HNSCC) continues to pose a major global health challenge, with over 600,000 new cases diagnosed annually and persistently poor survival outcomes despite advances in surgery, radiotherapy, and immunotherapy. Growing evidence implicates metabolic reprogramming, including enhanced glycolysis, glutaminolysis, lipid synthesis, and one-carbon/redox flux as a central driver of HNC initiation, progression, and therapy resistance. In contrast, metabolic crosstalk within the hypoxic, acidic tumor microenvironment (TME) further shapes immune evasion and stromal support. Recent innovations in mass spectrometry platforms (LC-MS, GC-MS, NMR) have attracted attention in clinical therapeutics, and spatial metabolomics imaging techniques now enable high-resolution in situ mapping of metabolites, revealing intratumoral heterogeneity and offering new insights into tumor-immune–stromal interactions and potential biomarkers for precision oncology. In this review, we integrate critical methodological considerations from sample collection and data-analysis workflows to analytical pitfalls with a balanced, pathway-focused analysis of HNSCC dysmetabolism, examine tumor immune stromal metabolic interactions, and highlight translational opportunities through emerging biomarkers, targeted inhibitors, and cutting-edge approaches such as single-cell and AI-driven metabolomics to chart a roadmap toward precision oncology for HNSCC. Full article

Vascular ageing is a complex process marked by progressive endothelial dysfunction, chronic low-grade inflammation (“inflammageing”), and reduced regenerative capacity, driven in part by an imbalance between protective endothelial autophagy and cellular senescence characterized by a proinflammatory senescence-associated secretory phenotype (SASP). Disruption of this autophagy–senescence axis accelerates vascular inflammation, arterial stiffening, and atherogenesis. High-intensity interval training (HIIT), consisting of repeated bouts of near-maximal anaerobic effort with recovery periods, is widely used by both elite and recreational athletes and is increasingly recognized as an effective nonpharmacological strategy to enhance endothelial function, arterial elasticity, and mitochondrial biogenesis. However, excessively intense or poorly structured HIIT, particularly in the absence of adequate recovery or in individuals with underlying cardiometabolic or vascular vulnerability, may induce endothelial stress and promote maladaptive vascular remodelling, including calcification and plaque instability. These considerations underscore the need for refined individualized exercise prescription strategies that balance performance benefits with endothelial protection. Based on these observations, here, we introduce a novel conceptual framework, “shear dose–calibrated HIIT,” designed to understand and define an optimal shear dose capable of maximizing autophagic flux while minimizing SASP activation. Experimental and clinical evidence of HIIT-induced effects on flow-mediated dilation (FMD), pulse wave velocity (PWV), and redox biomarkers is presented, followed by the proposal of a biomarker panel for assessing autophagic flux and cellular senescence in peripheral samples (peripheral blood mononuclear cells (PBMCs), extracellular vehicles (EVs), and plasma). This integrative approach, which combines vascular mechanotransduction, redox biology, and autophagic signalling, provides a novel translational perspective on how individually calibrated HIIT can promote vascular longevity and reduce cardiometabolic risk associated with aging and metabolic syndrome. Full article

Paint manufacturing wastewater contains complex mixtures of solvents, resins, surfactants, pigments, and polymeric additives that result in high chemical oxygen demand (COD), toxicity, and poor biodegradability. Conventional physicochemical treatment provides limited removal of dissolved organics, and the pollutant-level behavior of paint effluents during biological treatment remains insufficiently characterized. This study addresses this gap by evaluating a sequential anaerobic–aerobic batch process treating three distinct synthetic paint wastewater samples. This study is a comparative investigation of sequential biological treatment across multiple paint wastewater variants, combined with high-resolution LC–MS to track compound-level transformations. Treatment performance was assessed through COD removal, biogas generation, pH and redox behavior, and LC–MS profiling of organic contaminants. The anaerobic stage achieved 70–95% COD removal depending on wastewater type. Aerobic polishing increased overall removal efficiencies, while PWW3 exhibited reduced stability during extended operation. LC–MS analysis showed substantial decreases in the number and intensity of chromatographic peaks and demonstrated degradation of phthalates, glycol ethers, organophosphate plasticizers, and solvent-derived compounds. The study provides integrated performance- and pollutant-level assessment of sequential anaerobic–aerobic treatment of paint wastewater and demonstrates the influences of wastewater heterogeneity in biological degradation pathways. Full article

In this study, an enzyme-free electrochemical sensor based on zinc oxide (ZnO) nanorods synthesized by the thermal decomposition of zinc acetate is presented. The suggested approach ensures simplicity, environmental friendliness, and scalability of the process without the use of an autoclave or high pressure. The morphology and structure of the samples are studied using SEM, TEM, XRD, Raman, FTIR, XPS, PL, and UV-Vis spectroscopy. It is found that heat treatment at 450 °C increases the degree of crystallinity, increases the size of crystallites, and reduces the concentration of surface defects, which leads to improved optical and electrochemical characteristics of the material. Beyond conventional sensitivity metrics, our study demonstrates that the selective detection of ascorbic acid (AA) and uric acid (UA) can be achieved by controlling the applied potential on a single ZnO electrode, an approach that leverages differences in redox energetics and surface interaction dynamics rather than complex surface functionalization. It is shown in this work that the synthesized ZnO samples subjected to heat treatment in air at 450 °C exhibit high sensitivity to ascorbic acid (9951.87 μA·mM⁻¹·cm⁻²; LoD = 1.11 μM) at a potential of 0.2 V and to uric acid (5762.48 μA·mM⁻¹·cm⁻²; LoD = 1.71 μM) in a phosphate buffer solution (pH 7) at a potential of 0.4 V with a linear range of 3 mM, offering a way to create simplified multicomponent electrochemical biosensors based on potential-controlled selectivity. Full article

Trace metal contamination in lotic freshwater systems exhibits pronounced heterogeneity arising from coupled hydrological connectivity, geochemical partitioning, and anthropogenic forcing, complicating exposure characterization in urban and peri-urban catchments. Addressing this complexity requires integrative analytical approaches capable of deciphering system-level controls, prompting an investigation of the environmental structuring and governing controls of dissolved trace metal signatures in a human-impacted stream using a system-oriented computational framework. To capture temporal variability associated with seasonal hydrological contrasts and heterogeneous pollution inputs, a station-based, season-resolved sampling strategy was implemented during the wet and dry seasons. Physicochemical gradients (pH, temperature, dissolved oxygen, and electrical conductivity), inorganic nitrogen species (NH₃, NO₂⁻, and NO₃⁻), and phosphorus fractions (total phosphorus, TP; total orthophosphate, TOP; soluble reactive P, SRP) were jointly analyzed with dissolved concentrations of chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), cadmium (Cd), mercury (Hg), and arsenic (As). Regression-based machine learning models were used to quantify element-specific sensitivities to hydrochemical drivers under wet–dry periods and to identify optimal predictive configurations. Predictive performance was consistently high for trace metals (R² generally >0.95), with Random Forest providing the best accuracy for Cr, Ni, Pb, Cd, As, and Hg, whereas Cu was most reliably captured by an XGBoost tree ensemble (R² = 0.994). Explainability analyses revealed heterogeneous, metal-specific control regimes: Cr was primarily driven by temperature, Ni by NO₂⁻ and redox-sensitive conditions, Cd by NH₃ and temperature, and As by Hg in combination with phosphorus-related and redox-linked proxies, while Pb showed comparatively lower predictability relative to other metals. Trace metal distributions are therefore structured primarily by differential environmental sensitivity rather than uniform source-driven inputs, reinforcing the need for integrative computational frameworks when interpreting freshwater contamination under intensifying anthropogenic and climatic pressures. Full article

The conversion of low-cost, widely available, and renewable agricultural and forestry biomass waste into high-performance electrode materials for supercapacitors has attracted significant research interest. In this study, bamboo was used as a raw material to prepare bamboo-derived activated carbon (BAC) and nitrogen-doped biomass activated carbon (N-BAC) via a two-step process involving carbonization and KOH activation. The obtained materials were subsequently evaluated as electrode materials for supercapacitors. The effects of carbonization temperature and time, activation temperature and time, and impregnation ratio on the structural properties and iodine adsorption capacity of the activated carbons were systematically examined. The results revealed that all process parameters influenced the iodine adsorption value of the samples in a volcano-type trend. The BAC prepared under optimized conditions (carbonization at 600 °C for 60 min, activation at 850 °C for 60 min, and an impregnation ratio of 6:1) exhibited the highest specific surface area (3013.30 m²/g), a total pore volume of 1.5813 cm³/g, and an average pore diameter of 2.0992 nm. Although nitrogen doping slightly reduced the specific surface area and pore volume of BAC, the introduced nitrogen-containing functional groups participated in redox reactions with the electrolyte, leading to a significant enhancement in the electrochemical performance of N-BAC. In a 6.0 M KOH electrolyte at a scan rate of 0.01 V/s, the specific capacitance of N-BAC reached 288.8 F/g, exceeding that of the optimized BAC (180.85 F/g). The supercapacitor assembled with N-BAC demonstrated a high energy density of 14.4 Wh/kg at a power density of 73.1 W/kg in aqueous electrolyte, the specific capacitance retention rate is about 90.3% after 5000 cycles between −1.2 V and 0 V at a scan rate of 10 mV/s. Overall, this work successfully developed high-performance supercapacitor electrode materials, providing a promising approach for the high-value utilization of biomass resources. Full article

Modern oceanographic studies demonstrate that marginal seas and semi-restricted marine environments, including epicontinental seas and carbonate platforms, are highly sensitive to changes in circulation, freshwater input, stratification, and redox conditions, allowing climatic perturbations to be recorded with high fidelity. Understanding the behavior of such systems under icehouse conditions is therefore important for interpreting climate variability in both ancient and modern oceans. The Late Paleozoic Ice Age was a prolonged icehouse interval characterized by repeated glacial and interglacial oscillations, yet its climate dynamics are still mainly constrained by Gondwanan glacigenic records and low-latitude carbonate successions. High-resolution climate information from mid-latitude regions remains limited. The purpose of this study is to obtain high-resolution mid-latitude geochemical constraints on climate variability during the Late Paleozoic Ice Age using a semi-restricted marine carbonate succession. Specifically, this study aims to (1) establish high-resolution carbon and oxygen isotope records from well-preserved carbonate samples spanning the Visean to Asselian interval; (2) identify and characterize major glacial to interglacial cycles recorded in the succession; (3) evaluate the extent to which semi-restricted paleogeography amplifies isotopic responses relative to coeval low-latitude open-marine settings and (4) assess the climatic significance of a short-lived negative carbon isotope excursion during the middle Bashkirian. Here we present high-resolution carbon and oxygen isotope records from a Visean to Asselian marine carbonate succession deposited in a semi-restricted basin. Stable isotope analyses of well-preserved carbonate samples document temporal variations in carbonate carbon and oxygen isotopes. The records resolve at least three major glacial to interglacial cycles, with isotope shifts substantially larger than those reported from coeval low-latitude open-marine settings. Carbon isotope variations reach up to 7.7‰, while oxygen isotope variations reach up to 9.2‰. These pronounced responses are attributed to semi-restricted paleogeography, facies heterogeneity, and the sensitivity of marine carbonate systems to stratification, redox variability, and organic carbon cycling. A short-lived negative carbon isotope excursion during the middle Bashkirian may record a Northern Hemisphere deglaciation event superimposed on the broader Gondwanan icehouse background, a signal that is not clearly expressed in other regions. Overall, this study describes new mid-latitude geochemical constraints on Late Paleozoic climate variability and offers valuable analogs for understanding climate responses in modern marginal marine systems. Full article

(1) Background: Acidogenic Western-style diets disrupt gut bacteria promoting obesity-related diseases. Here, we investigated whether long-term feeding of alkalinized dietary casein as a protein source (ammonium hydroxide enhancement, AHE) modulates microbiome structure/functions under high-fat conditions, and normal diets, and whether these responses are sex-dimorphic. (2) Methods: C3H/HeJ mice (N = 256; equal sex distribution) received either control casein (CC), AHE casein (CCN), high-fat casein (HFC), or AHE high-fat casein (HFCN) diets from 6 to 18 months. Body mass and survival were tracked; fecal samples collected at 16 months were sequenced and underwent shotgun metagenomics. (3) Results: Diet and sex jointly shaped host metrics. AHE diets taxonomically showed an abundance of Verrucomicrobiota phyla predominating in most cohorts, notably Akkermansia muciniphila. Within Pseudomonadota, Christensenella was identified, along with other taxa associated with beneficial health outcomes, including Lactococcus lactis, Lactococcus cremoris, Pediococcus acidilactici, and families Lachnospiraceae/Oscillospiraceae. Additionally, sex- and diet-dependent advantageous enriched functions associated with AHE that enhanced electron transport, B-vitamin cofactor pathways, and mucosal/redox support were observed. (4) Conclusions: In the long term, pH-directed protein chemistry is a tractable lever for gut ecology during high-fat feeding, enriching and promoting the balance of beneficial taxa, providing a mechanistic bridge between dietary acid load and microbiome remodeling. Full article

Organic dye pollution in industrial wastewater poses a serious environmental challenge, with methylene blue (MB) serving as a typical persistent pollutant due to its stable chemical structure, recalcitrance to degradation, and eco-toxicity. Conventional physical, chemical, and biological treatment methods suffer from limitations such as insufficient efficiency, high cost, or the tendency to generate secondary pollution. Based on green and sustainable photocatalysis technology, this study designed and prepared a NiO/SrTiO₃ p-n heterojunction photocatalysts, aiming to broaden the light-response range and enhance charge-carrier separation efficiency. The optimal sample (NiO (10%)/SrTiO₃) achieved complete photocatalytic degradation of MB within 9 min, with an apparent rate constant 34.6 times that of pure SrTiO₃. It also showed good cyclic stability. Trapping experiments confirmed that •OH and •O₂⁻ were the key active species in the degradation process. Combined with band structure and PL analyses, an S-scheme charge-transfer mechanism was proposed, clarifying the critical role of the built-in electric field at the heterojunction interface in promoting carrier separation while maintaining high redox capability. This work not only provides a new pathway for developing efficient and stable SrTiO₃-based photocatalysts but also offers theoretical and experimental support for the practical application of p-n heterojunction photocatalysts in environmental pollution control. Full article