Search Results (549)

Silicon (Si) accumulation is a widespread anti-herbivore defence in grasses, yet little is known about how insects counteract silicification, including via compensatory feeding, or whether Si-mediated changes in plant stoichiometry also influence herbivore performance. We examined how Si supplementation alters foliar Si, carbon (C), nitrogen (N), and phosphorus (P) in two grasses with contrasting accumulation strategies, Brachypodium distachyon (high accumulator) and Lolium arundinaceum (moderate accumulator), and the consequences for growth and feeding by Helicoverpa armigera. Plants were grown hydroponically with or without Si, and herbivore relative growth rate (RGR), relative consumption (RC), and Efficiency of Conversion of Ingested food (ECI) were measured. Si supplementation had stronger effects on herbivore performance in B. distachyon compared with L. arundinaceum. RGR declined by 126% on B. distachyon compared with 40% on L. arundinaceum. Herbivores increased RC on Si-supplemented L. arundinaceum, with RC positively correlated with foliar Si concentrations, but no compensatory feeding occurred on B. distachyon. N and P concentrations were positively correlated with RGR in L. arundinaceum and ECI in B. distachyon. In conclusion, the degree of Si accumulation in grasses influences both plant stoichiometry and has contrasting impacts on herbivore feeding strategies. Full article

Microbial nutrient cycling in afforested mine soils may be affected by the plant litter quality. This study investigated how different tree species—Scots pine (Pinus sylvestris), silver birch (Betula pendula), European larch (Larix decidua), and black alder (Alnus glutinosa)—influence microbial carbon (C), nitrogen (N), and phosphorus (P) limitations in reclaimed sandy mine soils. We combined substrate-induced respiration (SIR) and ecoenzymatic stoichiometry (EES) to diagnose these metabolic constraints. The SIR analysis revealed a universal primary limitation by labile C across all tree species, with glucose addition stimulating respiration by 271%–333%, regardless of the soil organic carbon content. However, EES revealed distinct secondary nutrient constraints driven by species-specific litter quality. Alder stands exhibited severe P limitation, likely due to high P demand for symbiotic N-fixation and intense competition for P between trees and microbes. In contrast, birch stands showed stoichiometric homeostasis and a slight N deficiency. Coniferous species exhibited P limitation and low enzymatic activity, indicating a strategy focused on intensive nutrient acquisition under low-energy conditions associated with recalcitrant needle litter. These findings demonstrate that while energy limitation is a universal constraint in mine soils, tree species determine the nature and intensity of secondary nutrient limitations due to differences in litter stoichiometry. Full article

Designing materials with superior corrosion resistance is critical for seawater electrolysis systems to achieve efficient and long-term stable hydrogen production. In the current study, CrAlN coatings were deposited on TA1 titanium substrates by reactive magnetron sputtering with nitrogen flow ratios ranging from 40%–70% to investigate the effect of nitrogen stoichiometry on corrosion behavior in simulated alkaline seawater (pH ≈ 14, chloride-containing). Microstructural characterization (Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS), Grazing Incidence X-Ray Diffraction (GIXRD), Transmission Electron Microscopy (TEM), X-Ray Photoelectron Spectroscopy (XPS), Atomic Force Microscopy (AFM)) reveals that a 60% nitrogen ratio promotes grain refinement, improved CrN/AlN phase stoichiometry, and reduced oxygen-related defects, resulting in a dense columnar structure with minimized diffusion pathways. Electrochemical measurements show that this condition yields the lowest corrosion current density (0.297 μA·cm⁻²) and the highest polarization resistance (123.9 kΩ·cm²). Electrochemical impedance spectroscopy confirms enhanced charge transfer resistance and suppressed ionic transport at the coating/electrolyte interface. The results establish a clear correlation between nitrogen-controlled phase evolution, defect density, and passivation kinetics in highly alkaline chloride environments relevant to seawater electrolysis. This study targets the fabrication of protective coatings for alkaline seawater electrolysis via nitrogen flow ratio optimization. The optimized CrAlN coating achieves remarkably improved corrosion resistance compared with existing coatings, showing promising practical value for long-term stable seawater electrolysis. Full article

Arsenopyrite (FeAsS) is an important sulfide that holds gold in orogenic systems. Its arsenic content is often used as a proxy for gold fertility. However, arsenopyrite from the Um Rus gold deposit in Egypt’s Central Eastern Desert shows a complicated gold distribution that makes simple Au-As correlations hard to make. Integrated electron microprobe analysis (EMPA), laser ablation ICP-MS, and principal component analysis (PCA) reveal three unique textural and geochemical domains. Fine-grained arsenopyrite inclusions within pyrite aggregates (28–31 at% As) are devoid of detectable gold; PCA elucidates 84% of their variance through Fe–S versus Co-As substitution (PC1: 61.8%) and Pb-decoupled variability (PC2: 22.2%), suggesting crystallization from a Co-rich, Au-poor fluid. On the other hand, coarse oscillatory-zoned arsenopyrite can hold up to 6154 ppm of invisible gold. This is because of a moderate Au-As substitution (R = 0.41063, p = 0.08074) that was overprinted by a separate Au-Ag-Sb-Te hydrothermal pulse (Au–Ag: R = 0.97762; Au–Sb: R = 0.97608). PCA finds four parts (72.8% variance): Ag-Cu-As associations (PC1: 25.1%), Te versus Bi-Au signatures (PC2: 17.8%), Fe–S stoichiometry (PC3: 17.1%), and an Au versus Pb-decoupled event (PC4: 12.9%). This shows that minerals formed in more than one stage. Irregular As-rich overgrowths, containing ≤950 ppm gold and lacking significant Au–As correlation (R = −0.14011, p = 0.56726), show PCA (74.3% variance) that highlights S-As contrasts (PC1: 25.2%), Co-Ni enrichment (PC2: 18.8%), Cu-Fe-Ni associations (PC3: 16.2%), and a late Au-decoupled event (PC4: 14.2%), indicating barren recrystallization. These results show that just adding arsenic is not a good way to tell if gold is fertile. The highest amounts of invisible gold, on the other hand, are found in oscillatory-zoned domains with Ag-Sb-Te signatures. This research highlights the importance of combining PCA, geochemistry, and microtextures to differentiate auriferous from barren arsenopyrite, thereby enhancing exploration methodologies for structurally intricate orogenic gold systems. Full article

The clinical utility of the anticancer drug camptothecin (CPT) is limited by its poor aqueous solubility and instability in the bloodstream, hindering bioavailability and efficacy. This study explores the complexation of CPT with carboxymethyl-beta-cyclodextrin (cmβCD) to overcome these limitations. Fluorescence spectroscopy and molecular modeling demonstrated 1:1 inclusion complexes, with stability constants governed by electrostatic interactions that were inversely correlated with pH. To validate this effect, a cationic amino-beta-cyclodextrin (amβCD) was used as a mechanistic control, revealing that Coulombic forces significantly modulate binding strength and stoichiometry. Crucially, cmβCD enhanced CPT solubility by up to 11-fold at 14 × 10⁻³ moldm⁻³, enabling a 385-fold increase in drug loading into liposomal carriers compared to the cyclodextrin-free system. Fluorescence-based release studies indicated high liposomal stability at physiological pH and partial CPT release under acidic conditions. Furthermore, CPT-loaded liposomes demonstrated cytotoxicity against cancer cell lines, particularly BT-474, with IC₅₀ values generally comparable to or slightly higher than those of free CPT and the CPT:cmβCD complex, likely due to the distinct lysosomal cellular uptake pathway. This work highlights cmβCD complexation as a promising strategy to enhance CPT solubility and liposomal loading for improved drug delivery. Full article

Soil organic carbon (SOC) responses to straw return are strongly influenced by active carbon dynamics and extracellular enzyme responses, yet how these processes vary with initial SOC status and long-term straw-return history remains unclear. To address this question, we conducted a controlled incubation experiment using soils from long-term straw removal (CK) and straw return (SR) plots at two sites with contrasting SOC levels: a carbon-poor fluvo-aquic soil in Quzhou (QZ) and a carbon-rich black soil in Gongzhuling (GZL). Three fresh-straw input levels were imposed, and CO₂ release, SOC, labile C and N pools, extracellular enzyme activities, and ecoenzymatic stoichiometry were determined. Fresh-straw input markedly stimulated carbon mineralization in both soils, but SOC responses differed substantially. In QZ, SOC increased 12.1–15.7% at day 7 (vs. T0) and remained 6.7–12.1% above the control at day 90 under the long-term straw-return background. In contrast, GZL showed only minor early SOC responses, and doubled straw input reduced SOC 4.9–9.5% at day 90 despite a stronger dissolved organic carbon (DOC) pulse and greater cumulative CO₂ release. Enzyme responses also differed between soils: higher straw input in QZ enhanced β-cellobiohydrolase (CBH), β-xylosidase (BX), and especially L-leucine aminopeptidase (LAP), accompanied by lower ecoenzymatic C:P and higher vector angle, whereas GZL showed later activation of CBH, BX, and NAG with only slight changes in vector angle. Overall, our results indicate that initial SOC status and long-term straw-return history jointly regulate whether fresh-straw input promotes net SOC accumulation or enhanced mineralization. Full article

Vegetation restoration profoundly impacts soil carbon (C)-nitrogen (N)-phosphorus (P) cycling in arid sandy lands, with vegetation type critically regulating accumulation patterns. However, the magnitudes of soil nutrients and stoichiometry for different vegetation types are still largely unknown. Thus, we conducted a regional-scale study to evaluate the soil nutrients and nutrient stoichiometry under four typical vegetation types in the Mu Us Sandy Land (MUS), including monoculture arbor (MA), monoculture shrub (MS), arbor-shrub mixed (MAS), and monoculture herbaceous (MH), with cropland (Cr) and bare sand (Bs) controls. Our results showed that vegetation type significantly affected SOC and TN content. MS (30–40 years), MA (>40 years), and MH exhibited significant increases of 285.5–305.8% in SOC and 293.6–374.6% in TN in the topsoil, respectively. MS (30–40 years) and MH demonstrated increases of 399.1% and 283.3% in SOC and 250.2% and 162.8% in TN in the subsoil. However, MAS had no significant effect on SOC and TN. MA (>40 years) resulted in a higher TP in the subsoil. Compared to Bs, humic substances significantly increased by 111.1–171.6% under MA (>40 years), MS (>40 years), and MH, exhibiting positive correlations with SOC. Moreover, MAS treatment resulted in a higher C:N, while the MH resulted in a higher C:P and N:P in the topsoil. Despite stable total phosphorus (TP), elevated C:P and N:P ratios under MH indicated emerging P limitation in restoration. Therefore, long-term monoculture shrub, arbor, and herbaceous vegetation effectively enhances soil fertility in arid sandy lands through long-term SOC accumulation and humic substance formation. 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

Lubricants are essential for water-based drilling fluids. Catechol-based lubricants provide improved lubrication performance owing to their strong adhesion ability through the formation of coordination bonds inspired by mussel adhesion. However, the conventional synthetic ester and amide lubricants suffer from loss of adhesive capability due to hydrolysis and autoxidation. Inspired by mussels and melanin biosynthesis, a biomimetic strategy was developed to synthesize a high-adhesion lubricant with good stability via thiol-quinone Michael addition to restore and stabilize the catechol moiety. Bisphenol A was oxidized to the corresponding quinone using 2-iodoxybenzoic acid. Subsequent Michael addition reaction with 1-octadecanethiol produced a thiol-functionalized lubricant containing catechol moieties and long alkyl chains through an S-catecholyl linkage. Biomimetic principles were incorporated into both the molecular structure and the synthetic route, emulating the structural and functional features of mussel adhesion and melanin biosynthesis. Octadecanethiol provided sulfur-containing extreme-pressure functionality and contributed to strong adsorption on metal surfaces. The molecular structure was confirmed by FTIR, ¹H NMR, and ¹³C NMR. The thiol-functionalized lubricant formed strong coordination with Fe³⁺ and Fe²⁺ ions across a wide pH range, with an apparent complexation stoichiometry of 1:1 and conditional stability constants of 4.09 and 5.02, respectively. Bis-coordination formed a cross-linking network. It exhibited good resistance toward autoxidation and thermal stability up to 350 °C. In bentonite-based drilling fluids, the extreme pressure lubrication coefficient and adhesion coefficient at a 1% addition were 0.06 and 0.07, respectively. The coefficient of friction and wear scar diameter were 0.09 and 0.63 mm, respectively. The increased contact angle confirmed strong adsorption of the lubricant on metal surfaces. The lubricant combined strong adhesion, high stability, and excellent compatibility with drilling fluids, highlighting its potential as an advanced biomimetic lubricant. This biomimetic thiol-quinone addition strategy provides an effective approach to overcome the instability of conventional catechol-based lubricants. Full article

Clarifying the responses of microbial communities in distinct microhabitats like roots, the soil, and litter layers to secondary succession is critical for predicting the effects of global climate change on ecosystem functions. We investigated the microbial activities, compositions, and networks in these microhabitats of Fagus lucida forests ranging from 40 to 200 years. The results showed that soil physicochemical properties decreased with forest succession, except for NH₄⁺-N and available phosphorus, which decreased at the early stage. All vector angles of extracellular enzyme stoichiometry that were greater than 45° indicated that phosphorus was the key limiting element for microorganisms. The microbial community shifted from r- to K-strategists with forest succession, displaying the replacement of most bacterial phyla by Proteobacteria and Acidobacteriota, and an increase in the Acidobacteriota: Proteobacteria ratio, especially in the soil and litter layers. Soil properties, particularly NH₄⁺-N and pH, significantly affected the bacterial diversity and structure. Moreover, the bacterial network complexity increased with succession, particularly in the litter layer, and the topological properties of bacterial networks showed a stronger influence on microbial activities compared with those of fungal networks. The richness of keystone taxa in the litter layer was higher than in the soil layer and roots. However, the fungal community dominated by symbiotrophs showed lower sensitivity to soil nutrient changes and greater resilience to forest succession, displaying stable diversity and decreased network complexity, particularly in the roots. Ectomycorrhizal fungi (e.g., Russula) dominated the fungal guilds, and their abundance increased with forest succession, accompanied by a decrease in pathogenic fungi. Plant roots with significantly higher phosphatase activities played a stronger role than soils in structuring the litter microbial community, as reflected by similar carbon- and nitrogen-acquiring enzyme activities, microbial compositions, a greater share of taxa, and closer community distance. Our results revealed the increasingly important role of plant roots with forest succession in structuring the microbial community and nutrient cycling in the soil and litter layers. Full article

P2/O3-type Ni/Mn-based layered oxides are regarded as promising cathode materials for sodium-ion batteries (SIBs) because of their high energy density. However, their practical application is limited by low initial Coulombic efficiency, sluggish Na⁺ kinetics, transition-metal dissolution/migration and irreversible phase transitions during cycling. Herein, a controlled P2 phase was achieved through elemental ratio regulation, enabling systematic synthesis of a series of Na_xNi_0.4Co_0.1Mn_0.5O₂(x-NCMO) materials with tailored P2/O3 ratios. The optimized composition (x = 0.8), containing 16.6% P2 and 83.4% O3 phases, achieves an optimal phase equilibrium, thereby maximizing the synergistic coupling between the two layered polymorphs. This biphasic architecture demonstrates significantly enhanced Na⁺ transport kinetics and exceptional electrochemical performance, high initial capacity of 168.65 mAh g⁻¹ and excellent rate performance, maintaining 84.88 mAh g⁻¹ at 10 C, outperforming most reported P2/O3 biphasic cathodes. Structural analysis and electrochemical analysis reveal that elemental ratio regulation modulates the TM–O electronic structure, promotes electronic transport, and accelerates Na⁺ migration. These effects collectively reduce polarization, stabilize the structure, and thereby improve rate capability and long-term cycling capacity retention. This work provides an effective design strategy for designing high-performance layered oxide cathodes with improved structural and interfacial stability. Full article

Wollastonite-1A from Băița Bihor occurs in distal calcic skarns developed in the contact zone of a mainly granodioritic batholith, of Upper Cretaceous age, with Mesozoic limestones and dolostones. Wollastonite generally occurs in the inner part of metasomatic columns, in monomineralic skarns or associated with grossular and molybdenite-2H as ore mineral. The physical properties (i.e., refraction indices α = 1.616, β = 1.629, and γ = 1.631, 2V_α = 39° and density D_m = 2.922(3) g/cm³) are typical for a term close to the stoichiometry, which is confirmed by the chemical analysis. The chemical structural formula of the analyzed wollastonite-1A is (Ca_1.000Mg_0.002Mn_0.001Fe_0.001)(Al_0.004Ti_0.001Si_0.994)O₃, which closely approximates the ideal CaSiO₃. The Gladstone–Dale compatibility indices account for an excellent agreement between physical and chemical data. The mineral can be satisfactorily refined as triclinic, space group $P\overline{1}$, with R₁ = 0.0678 and cell parameters a = 7.9233(3) Å, b = 7.3203(3) Å, c = 7.0651(3) Å, α = 90.053(3)°, β = 95.208(3)°, γ = 103.384(3)°. Both the IR and Raman spectra principally reveal bands related to vibrations of bridged and non-bridged oxygens pertaining to SiO₄ structural tetrahedra. At Băița Bihor, wollastonite-1A is part of the prograde paragenesis, marked by a peak temperature of 550–600 °C. Full article

Soil carbon (C), nitrogen (N), and phosphorus (P) stoichiometry is essential for maintaining fertility and ecosystem functioning, yet its spatial patterns and drivers in large-scale agricultural regions remain unclear. We collected 225 topsoil samples across the Songnen Plain, Northeast China, and used geostatistical methods to map the spatial distributions of soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), and their ratios (C:N, C:P, N:P). Feature importance and correlation analyses were employed to assess the relative influence of environmental factors. Results revealed significant spatial heterogeneity, with a consistent north-high, south-low pattern for all elements and ratios. Mean C:N, C:P, and N:P ratios were 11.6, 32.8, and 2.8, respectively. SOC was the dominant controlling factor (importance: 0.5–0.6), showing strong positive correlations with all ratios. Mean annual temperature exerted significant negative effects, while precipitation had limited influence, primarily on C:N. Soil type also mattered, with black soils exhibiting the highest C:N and C:P ratios (11.8 and 36.7). We conclude that soil C:N:P stoichiometry in the Songnen Plain is governed by hierarchical interactions of SOC, climate, and soil type. These findings provide a mechanistic framework for understanding regional nutrient patterns and support the development of spatially targeted management strategies for sustainable soil health. Full article

The use of one-step products and their applications in sensory applications has gained much importance. Herein, Schiff’s base fluorescent turn-on sensor, namely FBTS, was synthesised via a condensation reaction between 6-fluorobenzo[d]thiazol-2-amine and 2-hydroxybenzaldehyde. The probe FBTS exhibits an intense “turn-on” blue fluorescence upon binding to Al³⁺ ions in a dimethyl sulfoxide–water (DMSO–H₂O (8:2, v/v)) medium. From photoluminescence (PL) titrations, the detection limit (LOD) for Al³⁺ is estimated to be 0.14 microM, and the Benesi–Hildebrand plot-based association constant (K_a) of 5.4 × 10⁴ M⁻¹ confirm a strong association between FBTS and Al³⁺. Negligible interference is observed in the presence of other metal ions. From the pH effect studies, the optimal pH range for Al³⁺ detection is 7–9. The recyclable reversibility of FBTS + Al³⁺ complex has been demonstrated via the sodium salt of ethylenediaminetetraacetic acid (Na₂-EDTA) chelation. A Job’s plot and interrogations, such as high-resolution mass spectrometry (HR-MS), ¹H-nuclear magnetic resonance (NMR) titration, and density functional theory (DFT), verified the 1:1 stoichiometry of binding between FBTS and Al³⁺. Based on multiple analyses, the binding mode and mechanism have been detailed. In addition, the practical application of FBTS for detecting Al³⁺ is demonstrated using the strip paper method, fish analysis, spiked real sample analysis, and cellular imaging. Full article

Excessive accumulation of copper ions (Cu²⁺) in the environment and biological systems poses severe risks to ecological balance and human health, necessitating accurate detection and monitoring of Cu²⁺. Schiff base derivatives with favorable optical properties provide an efficient strategy for copper ion recognition. In this paper, fluorescent probe L (5-methyl-2-hydroxybenzaldehyde-(7-diethylaminocoumarin-3-formyl) hydrazone) was synthesized through a three-step reaction using 4-diethylaminosalicylaldehyde and diethyl malonate as starting materials. The structure of probe L was confirmed by melting point analysis, infrared spectroscopy, and nuclear magnetic resonance. Single-crystal X-ray analysis revealed that probe L crystallized into a triclinic lattice with space group $P_1^{-}$. Optical investigations, including UV–Vis spectroscopy, fluorescence spectroscopy, and aggregation-induced emission studies, demonstrated highly sensitive and selective fluorescence “turn-off” behavior of probe L towards Cu²⁺ ions in DMSO, with negligible interference from other metal ions. Job’s plot and crystallographic analysis revealed a 1:1 binding stoichiometry between probe L and Cu²⁺, forming the complex [Cu(L)]. Fluorescence titration experiments revealed a binding constant (K_b) of 5.2 × 10⁶ L/mol and a detection limit of 7.8 × 10⁻⁷ mol/L, indicating excellent sensitivity. These results suggest that probe L has considerable promise for Cu²⁺ detection in aqueous environments, with potential applications in environmental monitoring and public health protection. Full article