Search Results (5,378)

Compost instability and low nutrient content remain the primary constraints on the resource utilization of livestock manure compost. Although biochar and zeolite have individually demonstrated ameliorative effects, their combined application and the associated microbial mechanisms remain insufficiently understood. This study ran a 35-day composting trial with four treatments, which were a no-amendment control (CK); amended with 10% biochar (w/w, dry weight basis, T1); amended with 10% zeolite (w/w, dry weight basis, T2); and amended with 5% biochar plus 5% zeolite (w/w, dry weight basis, T3). The T3 group achieved an average thermophilic temperature of 58.37 °C, sustained a thermophilic phase for 10 days, and had the highest seed germination index (118.31%), exceeding those of the other groups. This group maintained higher observed total phosphorus and total potassium concentrations at compost maturity. It also presented a higher NH₄⁺-N concentration (410.00 mg/kg DM). Humic acid climbed to 57.67 g/kg DM by day 35. Microbial analysis showed that Actinobacteriota made up 60.54% of the bacterial community in T3, almost twice the share in CK (32.97%). These observational results indicate that biochar–zeolite co-addition provided complementary benefits for improving compost maturity and nutrient concentrations, offering a practical strategy for sustainable chicken manure management. Full article

Plants commonly encounter spatially heterogeneous distributions of nitrogen (N) forms and iron (Fe) in soils, but how N form modifies plant responses to heterogeneous Fe availability remains poorly understood. Using a split-root system, we examined the phenotypic responses of Arabidopsis thaliana and wheat to contrasting Fe availability combined with ammonium (NH₄⁺) or nitrate (NO₃⁻) supply. Plants were exposed to high (100 μM) or low (5 μM) Fe in combination with NH₄⁺ or NO₃⁻, either under homogeneous or spatially heterogeneous conditions. Within each species, NH₄⁺ and NO₃⁻ treatments were supplied at equivalent total N concentrations. In both species, high Fe combined with sole NH₄⁺ supply resulted in pronounced reductions in shoot and root growth, whereas spatial presence of NH₄⁺ and NO₃⁻ between root compartments was associated with improved growth. Under high-Fe conditions, sole NH₄⁺ supply to both root compartments (HAHA) resulted in pronounced reductions in shoot and root growth, whereas supplying NH₄⁺ and NO₃⁻ to separate root compartments (HAHN) was associated with improved growth. Under these conditions, shoot fresh weight in HAHN was 178% higher than that in HAHA in Arabidopsis and 231% higher in wheat. In wheat, root fresh weight under HAHN was 471% higher than under HAHA. Wheat exhibited stronger spatial differentiation of root growth between contrasting nutrient compartments, whereas Arabidopsis showed greater variation in whole-plant growth in response to N form. Chlorophyll accumulation also showed species- and Fe-dependent responses to N form. Overall, these results indicate that N form modifies plant phenotypic responses to heterogeneous Fe–N supply and that wheat exhibits greater root plasticity under spatially heterogeneous Fe–N conditions. The roles of plant Fe and N status, rhizosphere pH, and long-distance signaling in these responses remain to be determined. Full article

The sustainable management of olive pomace (OP) residues remains a major environmental challenge, requiring integrated strategies that enhance resource recovery while minimizing environmental impacts. This study evaluated the effects of OP-derived biochar (BC) produced at two pyrolysis temperatures (300 and 600 °C) and applied at two rates (5 and 10%, w/w) on composting performance and the physicochemical, biological, and nutrient characteristics of OP compost. Composting was initiated in a pilot-scale forced-aeration bioreactor to accelerate the decomposition of the composting mixture, after which the materials were transferred to indoor piles to complete the composting and maturation process. Two-way ANOVA showed that both BC pyrolysis temperature and application rate significantly affected several compost quality attributes, although their relative influence varied among the measured properties. The observed responses were consistent with differences in the physicochemical characteristics of the OP-derived BC resulting from the pyrolysis conditions. Compared with BC produced at 300 °C, BC produced at 600 °C significantly reduced moisture content (MC) from 17.81 to 11.44%, decreased bulk density (BD) from 0.69 to 0.52 g cm⁻³, increased organic matter (OM) from 70.61 to 82.78%, and raised compost pH from 7.67 to 8.43 (p < 0.001), and reduced microbial respiration from 2.00 to 1.60 CO₂ g⁻¹ OM day⁻¹ (p = 0.0270). Increasing the BC application rate from 5 to 10% significantly enhanced nitrogen (N) (1.64–1.79%), phosphorus (P) (0.57–0.67%), ammonium (NH₄⁺) (162–214 mg kg⁻¹), nitrate (NO₃⁻) (42.98–52.42 mg kg⁻¹), sulfur (S) (0.35–0.39%), and compost stability index (SI). Overall, the higher BC application rate, particularly when combined with BC produced at 600 °C, generally resulted in the most favourable compost characteristics, although several responses were statistically comparable with those obtained using BC produced at 300 °C and applied at 10%. Germination indices of 97.5–135.8% indicated that the final composts exhibited low phytotoxicity and generally mature. These findings indicate that integrating OP-derived BC into OP composting can improve the quality and stability of the resulting compost while providing an integrated strategy for the valorization of within circular bioeconomy approach. Full article

Background: Although intracellular delivery via endocytosis is a promising strategy for drugs acting in the cytosol or nucleus, many macromolecular therapeutics remain trapped within endosomal/lysosomal compartments, limiting efficient cytosolic delivery. In this study, we designed a novel functional hyaluronic acid (HA)-based polymer, HA–octahistidine (His8), by conjugating His8 to CD44-targeting HA, and evaluated its physicochemical properties, cellular uptake, and endosomal escape capability. Methods: HA–His8 was synthesized via 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide/N-hydroxysuccinimide (EDC/NHS)-mediated coupling and characterized using ¹H NMR spectroscopy. Particle size and zeta potential were measured via dynamic light scattering, and buffering capacity was evaluated using acid–base titration. Cellular uptake and intracellular localization were investigated in CD44-high MDA-MB-231 and CD44-low MCF-7 cells via confocal laser scanning microscopy. Cytotoxicity was evaluated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Results: Successful conjugation of His8 was confirmed with a degree of substitution of 4.66 mol% relative to HA carboxyl groups. HA–His8 exhibited a nanoscale hydrodynamic diameter under physiological conditions, which increased under acidic conditions together with changes in zeta potential. HA–His8 exhibited higher buffering capacity than free His8 and was preferentially internalized by CD44-high MDA-MB-231 cells compared with MCF-7 cells. Compared with unmodified HA, HA–His8 exhibited lower colocalization with LysoTracker that decreased over time, indicating reduced retention within acidic vesicles. HA–His8 also exhibited low cytotoxicity over the tested concentration range. Conclusions: His8 modification alters HA intracellular localization while preserving CD44 targeting, thereby facilitating endosomal escape. These findings highlight HA–His8 as a potential platform for the cytosolic delivery of macromolecular therapeutics, including proteins, peptides, and nucleic acids. Full article

Nitrogen (N) availability strongly influences tea growth and the accumulation of quality-related metabolites, but long-term responses to withdrawal of external N can vary among cultivars. In this study, we characterized phenotypic, spectral, biochemical, and transcriptomic responses of four Camellia sinensis accessions—‘Kolkhida’, ‘Karatum’, and γ-irradiation-derived mutant forms #582 and #619—during two, four, or six months of complete withdrawal of exogenous NH₄NO₃ in greenhouse sand culture. Phenotypic, spectral, and biochemical measurements included all four accessions at all three time points; RNA-seq data were available for all four accessions were represented at four and six months, whereas two-month point were available only for ‘Kolkhida’ and ‘Karatum’. Nitrogen withdrawal decreased L-theanine and caffeine and generally increased simple and gallated catechins, consistent with a change in carbon/nitrogen balance towards phenolic metabolism. The four cultivars exhibited markedly distinct responses. ‘Karatum’ showed the optimum resilience, with minimal phenotypic alteration and a neutral transcriptional response, while #582 demonstrated a stronger stress-associated phenotype and metabolic response. Within the available RNA-seq comparisons, DEG counts were lower at four months than at six months, while the two-month datasets for ‘Kolkhida’ and ‘Karatum’ contained the largest DEG sets for those two cultivars, suggesting a phased acclimation process. CsELIP1, CsSRG1, CsHHO2/4, CsNRT2.4, and CsTAT2 were identified as potential candidate genes associated with nitrogen limitation, flavonoid regulation, and amino acid metabolism. Our findings show that N-deficiency reactions in tea are highly cultivar- and time-dependent, making single-time-point evaluations insufficient. We propose ‘Karatum’ as a promising candidate for further evaluation in low-nitrogen dose–response and field trials based on our combined biochemical and transcriptional findings. Full article

Studying the relationships between understory plant diversity and soil physicochemical properties aids in understanding the sustainable development of plantation forests. Vegetation restoration in latosol gully erosion areas plays a key role in preventing soil erosion. Variations in understory plant diversity and soil physicochemical properties in areas that have undergone vegetation restoration subsequent to gully erosion are not well understood. In this study, we investigated the understory species composition, importance values, plant diversity, and soil physicochemical properties and explored their correlations following vegetation restoration using four forest types (Acacia mangium forest, Eucalyptus robusta forest, A. mangium–E. robusta mixed forest, and A. mangium–E. robusta–Schizostachyum pseudolima mixed forest) in the Mahuangling Watershed, Hainan Province. A total of 49 plant species belonging to 47 genera and 20 families were recorded. The E. robusta forest (31 species) and A. mangium–E. robusta mixed forest (27 species) had higher species richness and more complex community structures. The dominant shrub species were Rhodomyrtus tomentosa, Breynia fruticosa, Aporosa dioica, and Dodonaea viscosa, while the dominant herbaceous species were Ageratum conyzoides, Chromolaena odorata, Spermacoce alata, and Erigeron sumatrensis. In all four vegetation restoration forest types, the richness index in the herbaceous layer was higher than in the shrub layer, while the diversity index showed no significant difference between the shrub and herbaceous layers (p > 0.05). The soil bulk density ranged from 1.57 g·cm⁻³ to 1.63 g·cm⁻³, with the A. mangium forest having better soil total porosity (38.77%) and water-holding capacity (190.37 t·hm⁻²) than the other forests. NH₄⁺-N and NO₃⁻-N were lower in the E. robusta forest, while the A. mangium forest had significantly higher organic matter content (13.71 g·kg⁻¹). Correlation and redundancy analyses showed that soil water content, pH, and soil organic matter were key factors affecting herbaceous-layer and shrub-layer plant diversity. On the whole, we suggest that the planting of pure and mixed forests of A. mangium should be considered in future ecological restoration projects in the gully erosion area of Mahuangling in order to maintain the stability of understory plant diversity and improve latosol soil fertility. Full article

Selective degradation of antibiotics in complex wastewater is often hindered by the non-selective consumption of reactive oxygen species by coexisting organic matter. In this study, an adsorption-coupled heterogeneous Fenton-like strategy was developed to preferentially enrich tetracycline (TC) at the catalyst interface prior to oxidative degradation. MIL-53(Fe), MIL-101(Fe), and NH₂-MIL-101(Fe) were synthesized using a solvothermal method and systematically compared in terms of TC adsorption, catalytic degradation, and degradation selectivity in binary TC/glucose systems. Although MIL-101(Fe) exhibited the highest overall TC degradation efficiency, NH₂-MIL-101(Fe) showed the highest selectivity toward TC. At a TC/glucose concentration ratio of 2:2, NH₂-MIL-101(Fe) achieved a TC degradation selectivity of 73.1%, compared with 50.2% for MIL-101(Fe). Electron spin resonance and radical scavenging experiments demonstrated that ·OH was the dominant reactive species and that TC oxidation occurred predominantly at or near the catalyst surface. The enhanced selectivity was attributed to preferential TC adsorption followed by surface-localized oxidation and repeated adsorption–degradation cycles. Full-scan LC-MS analysis revealed several transformation-related ions, from which a tentative pathway involving possible N-demethylation, oxidative fragmentation, and ring-cleavage-related transformations was proposed; however, the individual product structures were not definitively identified. After five reuse cycles, the TC degradation efficiency remained above 75%, while the degradation selectivity decreased only from 74.7% to 68.7%. NH₂-MIL-101(Fe) also retained preferential TC removal in a TC-spiked domestic wastewater matrix. These results demonstrate that coupling preferential adsorption with localized Fenton-like oxidation provides an effective strategy for enhancing the selective removal of antibiotics from complex aqueous matrices. Full article

The discharge of chromium-containing wastewater into natural aquatic systems poses a substantial risk to both ecosystem integrity and human health. In this study, a pyrite-amended Leersia hexandra Swartz (L. hexandra) constructed wetland was established to investigate the mechanisms underlying pyrite-mediated regulation of wetland processes. In normal conditions, the presence of L. hexandra enhanced the removal of NH₄⁺-N, NO₃⁻-N, TN, and TP, with the maximum removal efficiencies increased by up to 35.4%, 17.8%, 9.5%, and 25%, respectively, compared with the constructed wetland without L. hexandra. Although Cr(VI) led to a general decline in removal efficiencies, appreciable removal of NH₄⁺-N, TN, TP, and COD was still sustained. Notably, under Cr(VI) stress, pyrite amendment improved the removal of NH₄⁺-N and COD, with maximum removal efficiencies reaching 99% and 87.5%, respectively, and achieving optimal overall efficiency. Moreover, physiological and biochemical assessments indicated that L. hexandra exhibited superior performance in the pyrite-amended system compared with the unamended control following Cr(VI) exposure, with the peak SOD activity decreased by 27.6%, peak POD activity decreased by 21.9%, peak CAT activity increased by 29.6%, and peak MDA content decreased by 29.4%, suggesting that pyrite mitigated Cr(VI) stress. Given the pivotal role of microbial assemblages in nutrient transformation, shifts in microbial community structure were further analyzed after pyrite addition, revealing discernible alterations. Collectively, these findings demonstrate that pyrite incorporation into L. hexandra constructed wetlands enhances the removal of specific nitrogen species under Cr(VI) stress, while its promotive effect on phosphorus removal remains comparatively limited. Full article

Emergency treatment of algal blooms in lake and reservoir source waters requires coagulants that remain effective under changing raw water conditions. This study compared polyaluminum chloride (PAC) and chitosan (CTS) in raw water collected from Yangku Reservoir during wet and dry seasons. Jar tests evaluated algal density, algal biomass, and nitrogen and phosphorus fractions across a 3~15 mg/L reagent-mass dosage range. Treatment performance differed between seasons. Mean algal density and soluble reactive phosphorus (SRP) removals in the wet season were 63.12% and 68.51%, respectively, and an apparent 70.05% decrease in measured NH₄⁺-N concentration was also observed. Because the fate of dissolved inorganic nitrogen was not resolved, the NH₄⁺-N decrease should not be interpreted as direct coagulative removal. Dry season water had higher algal density and a higher SRP/TP ratio. PAC maintained relatively stable algal biomass removal across seasons and showed stronger phosphorus removal, whereas CTS was more sensitive to seasonal changes in the raw water matrix. These findings support season-specific preliminary screening of coagulants while highlighting the need for residual-Al, pilot-scale, and process-mechanism validation before full-scale application. Full article

Integrated organic–inorganic soil amendments have been proposed as a strategy to improve soil fertility while maintaining crop productivity, yet their effects on seasonal nutrient dynamics and chile (Capsicum annuum L.) performance remain unclear. Two chile cultivars (‘NuMex Odyssey’, ‘NuMex Sandia Select’) were tested to evaluate the effects of organic and inorganic amendments on soil nutrient dynamics, chile vegetative growth, and fruit yield and dimensions across key growth stages. The amendments included an unamended control (CK), half-rate (CF) and full-rate (CFCF) chemical fertilizer, and three integrated amendments consisting of composted manure–biochar blend (CFMB), composted manure (CFM), and pea residues (CFP) applied at a 1:1 ratio with chemical fertilizer on a plant-available nitrogen (PAN) basis. CFCF produced the highest early-season availability of N, P, and K, whereas CFP and CFM provided a more gradual nutrient release pattern, maintaining PAN comparable to CFCF through flowering and sustaining P and K availability through harvest. ‘NuMex Sandia Select’ exhibited greater yield responsiveness to soil amendments, while ‘NuMex Odyssey’ produced fewer but higher dimension fruits. CFP maintained fruit yields comparable to CFCF while producing lower vegetative biomass. Correlation analyses showed that significant nutrient–plant relationships were concentrated at harvest, with soil NO₃⁻-N associated with fruit number and NH₄⁺-N with fruit dimensions. These findings indicate that partial substitution of mineral fertilizer with organic amendments may sustain nutrient availability and chile productivity while providing a more gradual nutrient release throughout the growing season. Full article

Low-temperature sintering flue gas contains both nitrogen oxides (NO_x) and carbon monoxide (CO), requiring bifunctional catalysts for concurrent pollutant abatement. Herein, CuSmTi composite oxides with an identical nominal composition were synthesized via impregnation, mechanical grinding, and sol–gel methods to examine the effects of preparation route on their structure, surface properties, and catalytic performance in coupled NH₃-SCR and CO oxidation. CuSmTi-SG exhibited the best performance, achieving >40% NO_x conversion at 125 °C, complete NO_x and CO conversion at 200 °C, and nearly 100% N₂ selectivity over 100–300 °C, with stable performance over 24 h. It possessed a higher surface area (131.4 m² g⁻¹), pore volume (0.230 cm³ g⁻¹), and smaller TiO₂ crystallite size (8.5 nm) than the other catalysts. Spectroscopic analyses showed that sol–gel synthesis altered the surface electronic states of Cu and Sm species, resulting in a higher Cu⁺ fraction and greater amounts of medium-to-strong Lewis acid sites and labile surface oxygen species. In situ DRIFTS indicated that CO oxidation proceeded predominantly via a Mars–van Krevelen mechanism over Cu⁺ sites, whereas NH₃-SCR mainly followed an Eley–Rideal pathway. CO and NH₃ preferentially interacted with different surface sites, resulting in limited mutual inhibition. These results demonstrate that the preparation route can modify the structure and surface chemistry of CuSmTi catalysts without changing their nominal composition, thereby affecting their performance in low-temperature NO_x and CO abatement. Full article

Background: Perfluorooctane sulfonate (PFOS) is a globally recognised persistent, bioaccumulative and toxic pollutant. Under China GB 5749-2022 and the US EPA 2024 drinking water MCL, permissible levels have fallen to 40 ng L⁻¹ and 4 ng L⁻¹, respectively, placing unprecedented demands on remediation technologies. Methods: An iron(III)–carboxylate metal–organic framework prepared from low-cost precursors (denoted MOF-LC, [Fe₃O(BDC)₃Cl]·x(solvent)) was synthesised via a one-pot solvothermal route from FeCl₃·6H₂O and terephthalic acid (H₂BDC). The material was characterised by PXRD, N₂ adsorption, FTIR, TGA, XPS, elemental analysis and ICP-OES. Adsorption performance was evaluated under varying initial concentrations, contact times, pH values, coexisting inorganic anions (Cl⁻, NO₃⁻, SO₄²⁻, HCO₃⁻, PO₄³⁻) and humic acid backgrounds, and by a panel of six water matrices. Results: MOF-LC exhibited a BET surface area of 1528 m² g⁻¹ and a dominant pore centred at 1.9 nm, which is geometrically compatible with the 1.36 nm molecular length of PFOS. Adsorption reached ≈95% of equilibrium capacity within 30 min and was best described by the pseudo-second-order model (R² = 0.998). Measured uptake reached 800.6 mg g⁻¹ at 298 K, corresponding to a Langmuir maximum capacity of 802 mg g⁻¹ (note that all adsorption experiments were conducted at mg L⁻¹ concentrations, several orders of magnitude above the regulatory limits cited above). Removal exceeded 88% across all six water matrices. PFOS removal efficiency fell from 99.2% to 85.8% over seven adsorption–regeneration cycles using a 1% NH₄Cl/methanol eluent, with 90.6% of the initial BET surface area retained and Fe leaching below 45 µg L⁻¹. Conclusions: Electrostatic, hydrophobic and pore confinement contributions are proposed as cooperative interpretations consistent with the observations. MOF-LC is identified as a technically promising laboratory-scale sorbent for PFOS removal from complex water matrices. Performance at environmentally relevant ng L⁻¹ concentrations and economic viability at scale remain to be established. Full article

The catalytic performance of copper-modified strontium titanate-based materials (SrTi_1−xCu_xO₃, where x = 0.02, 0.04, 0.06, and 0.10) in the NH₃-SCR and NH₃-SCO processes was studied. The catalytic materials were obtained by the modified Pechini method and characterized in terms of structural properties (XRD, XAS), surface composition (XPS), microstructural properties (SEM/EDS, SSA measurements), and reducibility (TPR). Catalytic activity, selectivity to N_2, and long-term stability in the NH₃-SCR and NH₃-SCO processes were experimentally verified. The catalytic materials consisted of agglomerates of nanocrystalline perovskite grains with homogeneously distributed copper, except for the material with the highest copper content. The catalytic activity of these materials was found to be highly dependent on copper loading, with STO_4Cu emerging as the optimal catalyst—the NO conversion in NH₃-SCR on the level of 88% and exceptional N₂ selectivity (>98%) was obtained at 275 °C, despite an extremely low Cu content (below 2 wt.%). Lower copper content (STO_2Cu) in catalysts appears to limit the low-temperature activity, which correlates with a higher Cu(I) contribution. On the other hand, the higher copper loading (STO_10Cu) triggers their aggregation. Twelve-hour isothermal stability tests confirmed robust long-term performance and stable N₂ selectivity for both the NH₃-SCR (at 250 °C) and NH₃-SCO (at 375 °C) reactions, demonstrating the potential of finely dispersed, low-loading copper perovskites for environmental catalysis. Full article

Paddy fields are a major agricultural hotspot for nitrous oxide (N₂O), contributing approximately 11% of global agricultural emissions. While elevated CO₂ and warming individually regulate N₂O emissions by modulating soil carbon, nitrogen (N) availability and microbial activity, the effects of concurrent elevated CO₂ and temperature (ECT) and the underlying microbial mechanisms under field conditions remain poorly understood. Here, we used a free-air CO₂ enrichment and temperature increase (T-FACE) system in a rice–wheat cropping system to investigate the impacts of ECT on N₂O emissions from rice paddies and identify the underlying biogeochemical and microbial mechanisms. Results showed that ECT increased area-scaled and yield-scaled N₂O emissions by 15.3% and 17.6%, respectively. Mechanistically, during the peak emission period, ECT significantly increased soil NH₄⁺–N content by 40.2% and the denitrification gene ratio [(nirK + nirS)/nosZ] by 27.5%. Furthermore, ECT increased the diversity of nitrifying communities but decreased that of denitrifying communities, while reshaping the composition of ammonia-oxidizing archaea and denitrifiers, thereby altering nitrification and denitrification. Overall, our field-based evidence suggests that ECT can stimulate N₂O emissions primarily by increasing soil N substrate availability and shifting denitrifier communities in ways that may favor N₂O accumulation. These findings offer mechanistic insights into climate-driven N₂O emissions. Full article

Distal-less homeobox 1 (DLX1) has emerged as a promising urinary biomarker for prostate cancer. This study developed a label-free piezoelectric acoustic biosensor for selective DLX1 detection using a quartz crystal microbalance (QCM). The QCM gold electrode was sequentially functionalized with L-cysteine, graphene oxide (GO), and an amine-terminated DLX1 capture probe covalently immobilized through EDC–NHS-mediated amide bond formation. Stepwise surface functionalization was characterized by X-ray photoelectron spectroscopy (XPS), supported by contact angle measurements, X-ray diffraction, and field-emission scanning electron microscopy. XPS provided multi-element evidence for Au–S thiolate formation, GO deposition, amide coupling, probe immobilization, and Watson–Crick hybridization with the synthetic DLX1 target. Under optimized conditions, the biosensor exhibited a linear response to DLX1 concentrations and achieved a limit of detection of 81.19 nM. Non-complementary sequences, including PCA3 and SARS-CoV-2, produced frequency shifts below 9 Hz, confirming high selectivity. Comparative experiments showed that GO-mediated covalent immobilization was essential for reliable detection, whereas direct DNA attachment to bare Au generated anomalous positive frequency shifts, which were attributed to weak physisorption. The proposed platform offers a sensitive and selective strategy for quantitative DLX1 detection and may support future point-of-care nucleic acid diagnostics. Full article