Search Results (128)

The complex system of high-entropy materials makes it challenging to reveal the specific function of each site for oxygen evolution reaction (OER). Here, with nickel foam (NF) as the substrate, FeCoNiCrMo/NF is designed to be prepared by metal–organic frameworks (MOF) as a precursor under an argon atmosphere. XRD analysis confirms that it retains a partial MOF crystal structure (characteristic peak at 2θ = 11.8°) with amorphous carbon (peaks at 22° and 48°). SEM-EDS mapping and XPS demonstrate uniform distribution of Fe, Co, Ni, Cr, and Mo with a molar ratio of 27:24:30:11:9. Electrochemical test results show that FeCoNiCrMo/NF has excellent OER characteristics compared with other reference prepared samples. FeCoNiCrMo/NF has an overpotential of 285 mV at 100 mA cm⁻² and performs continuously for 100 h without significant decline. The OER mechanism of FeCoNiCrMo/NF further reveal that Co and Ni are true active sites, and the dissolution of Cr and Mo promote the conversion of active sites into MOOH following the lattice oxygen mechanism (LOM). The precipitation–dissolution equilibrium of Fe also plays an important role in the OER process. The study of different reaction sites in complex systems points the way to designing efficient and robust catalysts. Full article

This study aimed to reveal the lipid composition and distribution and characterize the lipid metabolism profile in the three distinct parts of four guava varieties with varying textures and colors using liquid chromatography–electrospray ionization–tandem mass spectrometry. The four varieties, collected from a guava cultivation base in Danzhou City, Hainan Province, were “Zhenzhu” (white-fleshed hard-crispy guava, YBSL), “Bendi” (white-fleshed soft-waxy guava, RBSL), “Xiguahong” (red-fleshed hard-crispy guava, YHSL), and “Hongxin” (red-fleshed soft-waxy guava, RHSL). A total of 8242 lipids were detected, which were classified into four categories and 20 subcategories. Glycerolipids and glycerophospholipids are the most abundant types of lipids in guava. The lipid composition showed significant differences between hard-crispy and soft-waxy guavas. The red-fleshed guava varieties had 98, 57, and 96 differential lipid metabolites, whereas white-fleshed varieties had 68, 108, and 41 lipid metabolites in the epicarp, mesocarp, and endocarp, respectively. Moreover, comparative analysis of hard-crispy versus soft-waxy guavas with different colors revealed common differential lipids in the epicarp (29), mesocarp (21), and endocarp (18). The common differential lipids, including phosphatidylcholine (PC) (16:0/18:1), PC (18:1/18:1), and phosphatidylethanolamine (PE) (18:1/18:2), were found to be upregulated across all fruit parts, with greater abundance in soft-waxy guavas. They were mainly enriched in metabolic pathways associated with glycerophosphocholine and glycerophosphoethanolamine. These differential lipids may serve as potential biomarkers for evaluating guava quality. This study unveiled the lipid distribution and metabolic variations among different guava varieties. It also established a scientific foundation for improving guava varieties and implementing quality control measures. Full article

The increasing global demand for protein underscores the necessity for sustainable alternatives to soybean-based animal feed, which poses a challenge to human food security. Thus, the search for sustainable, alternative protein sources is transforming the feed industry in its effort to sustainable operations. In this study, a microbial consortium was subjected to adaptive laboratory evolution using non-protein nitrogen (NPN) and wheat straw as the sole carbon source. The evolved microbial consortium was subsequently utilized to perform solid-state fermentation on wheat straw and NPN to produce feed protein. After 20 generations, the microbial consortium demonstrated tolerance to 5 g/L NPN, including ammonium sulfate, ammonium chloride, and urea, which represents a fivefold increase compared to the original microbial consortium. Among the three NPNs tested, the evolved microbial consortium exhibited optimal growth performance with ammonium sulfate. Subsequently, the evolved microbial consortium was employed for the solid-state fermentation (SSF) of wheat straw, and the fermentation conditions were optimized. It was found that the true protein content of wheat straw could be increased from 2.74% to 10.42% under specific conditions: ammoniated wheat straw (15% w/w), non-sterilization of the substrate, an inoculation amount of 15% (v/w), nitrogen addition amount of 0.5% (w/w), an initial moisture content of 70%, a fermentation temperature of 30 °C, and a fermentation duration of 10 days. Finally, the SSF process for wheat straw was successfully scaled up from 0.04 to 2.5 kg, resulting in an increased true protein content of 9.84%. This study provides a promising approach for the production of feed protein from straw and NPN through microbial fermentation, addressing protein resource shortages in animal feed and improving the value of waste straw. Full article

Global industrialization has intensified the emission of emerging contaminants (ECs), posing a serious threat to the environment and human health. Persulfate-based advanced oxidation processes (PS-AOPs) have become a research hotspot due to their efficient degradation capability and environmentally friendly features; carbon-based materials are ideal catalysts for activating persulfate (PS) due to their tunable electronic structure, abundant active sites, and low cost. This study summarizes the application of carbon-based materials (graphene, single-atom catalysts (SACs), etc.) in PS-AOPs, and provides insights into the degradation mechanisms of radicals (e.g., sulfate radical (SO₄^−·), hydroxyl radical (·OH)) and non-radicals (e.g., ¹O₂(singlet oxygen), electron transfer). The removal efficacy of carbon-based catalysts for antibiotics, phenols, and dyes was compared, and the key degradation pathways were elucidated. In addition, the activation of PS can be accelerated, and catalytic efficiency can be improved by synergizing with ancillary technologies (e.g., light, electricity). Despite the great potential of carbon-based catalysts, their large-scale application is limited by the complexity of the catalyst preparation process and the lack of selectivity for complex water qualities. Future studies can accelerate the practical application of PS-AOPs in wastewater treatment through the precise design of SACs and the construction of multi-mechanism synergistic activation systems. Full article

Psectrocladius, a genus within the species-rich subfamily Orthocladiinae (Diptera: Chironomidae), remains poorly resolved in molecular phylogenetics due to limited available molecular data. Here, we sequenced and analyzed the complete mitogenomes of five Psectrocladius species, using two Rheocricotopus species as outgroups. Our results reveal that the mitogenomes of Psectrocladius are structurally conserved and retain a presumed ancestral gene order. The nucleotide composition of these newly generated mitogenomes exhibits a pronounced A + T bias, which is characteristic of typical insect mitogenomes. The substitution rates, estimated using Ka/Ks ratios, indicate that all protein-coding genes are under purifying selection. The strongest purifying selection pressure was observed in the CO1 gene, while the weakest was in the ND5 gene. Both the maximum likelihood and Bayesian inference trees consistently show the following topology: ((((P. schlienzi + P. bisetus) + P. barbimanus) + P. oligosetus) + P. aquatronus). This study provides key insights into chironomid mitogenomes and their gene properties, offering valuable reference data for future research. Full article

Proton exchange membrane fuel cells (PEMFCs), recognized as promising sources of waste heat for space heating, domestic hot water supply, and industrial thermal applications, have garnered substantial interest owing to their environmentally benign operation and high energy conversion efficiency. Since the uniformity of oxygen diffusion toward catalytic layers critically governs electrochemical performance, this study establishes a three-dimensional, non-isothermal computational fluid dynamics (CFD) model to systematically optimize the cathode flow channel width distribution, targeting the maximization of power output through enhanced reactant homogeneity. Numerical results reveal that non-uniform flow channel geometries markedly improve oxygen distribution uniformity, reducing the flow inhomogeneity coefficient by 6.6% while elevating maximum power density and limiting current density by 9.1% and 7.8%, respectively, compared to conventional equal-width designs. There were improvements attributed to the establishment of longitudinal oxygen concentration gradients and we alleviated mass transfer limitations. Synergistic integration with gas diffusion layer (GDL) gradient porosity optimization further amplifies performance, yielding a 12.4% enhancement in maximum power density and a 10.4% increase in limiting current density. These findings validate the algorithm’s efficacy in resolving coupled transport constraints and underscore the necessity of multi-component optimization for advancing PEMFC design. Full article

Species of Ganoderma (Ganodermataceae, Polyporales) have been extensively utilized in traditional Chinese medicine for over two millennia, owing to their remarkable medicinal properties and diverse chemical constituents. Hainan Island, located in tropical China, harbors a rich diversity of Ganoderma species. Among these, certain varieties referred to as “Lingzhi Wang” or “Zhu Lingzhi” by indigenous communities are distinguished by their diminutive pilei and slender stipes. Despite their traditional recognition, these species have been subject to morphological confusion. In this study, specimens labeled as “Lingzhi Wang” or “Zhu Lingzhi” were subjected to comprehensive morphological examinations and molecular phylogenetic analyses. The findings reveal that the Ganoderma species characterized by small pilei and gracile stipes encompass at least five distinct species. Among these, two are new to science: G. baisuzhenii and G. shennongii. The remaining three species, G. bambusicola, G. flexipes, and G. subflexipes, have been previously described. Taxonomically, G. bambusicola was reported for the first time on the Chinese mainland. This study provides a clearer taxonomic framework for these medicinally significant fungi. Full article

Coreius guichenoti, once widely distributed in the upper reaches of the Jinsha River, has become a nationally protected species in China due to the profound impacts of cascade reservoirs. To assess the influence of substrate on the suitability of spawning habitat for C. guichenoti, this study develops a substrate-inclusive habitat model using fuzzy logic based on expert knowledge. Taking the Pingdi Town section of the lower Jinsha River—a historical spawning site for C. guichenoti—as a case study from March to July 2020, we simulated changes in the spawning habitat suitability index (HSI) and compared the results with those from traditional models that exclude substrate factors. The results showed that in the first and second halves of May, Weighted Usable Area (WUA) and Overall Suitability Index (OSI) increased by 42.31% and 38.73%, respectively, while MSP exhibited dramatic increases of 236.04% and 614.56%. These improvements were primarily observed along the riverbanks, where HSI increased by approximately 0.25. From a management perspective, the HSI results provide a scientific basis for optimizing ecological flow regulation. Incorporating substrate factors into spawning habitat models offers a more objective and comprehensive assessment of habitat quality. Habitat restoration measures, such as targeted substrate improvement in key riverbank areas, may further increase habitat suitability, providing additional opportunities for conservation planning in regulated rivers. Full article

The temporal variations and spatial variations in the ionosphere during geomagnetic storms are exceptionally complex and drastic, significantly complicating ionospheric model construction. In this study, we present a multi-site, high-precision ionospheric vertical total electron content ($VTEC$) estimation method by constraining the $VTEC$ when the locations of ionospheric pierce points (IPPs), determined by multiple sites, are nearby. The root mean square error (RMSE) relative to the global ionospheric map (GIM) $VTEC$ is 3.22 TEC units (TECU), with a correlation coefficient of 0.98. This method enables the high-precision estimation of $VTEC$ at IPPs. Utilizing the Gauss–Markov Kalman filter data assimilation algorithm, we consider the relationship between various Dst indices and the ionospheric temporal scales, achieving a regional ionospheric total electron content $\left(TEC\right)$ Map during geomagnetic storms. This approach effectively monitors the impact of geomagnetic storms on the ionospheric total electron content $\left(TEC\right)$ and provides a more accurate representation of ionospheric changes during geomagnetic storms compared to the GIM $TEC$ Map and the International Reference Ionosphere (IRI)-2020 model. Full article

Currently, the existing high-pressure water mist fire protection systems in cold storage facilities face challenges in achieving efficient atomization and uniform water mist distribution, which may limit their effectiveness in rapid cooling and flame suppression. The objective of this investigation is to improve the performance of high-pressure fine water mist nozzles by integrating a Venturi microbubble generator to improve mist atomization and distribution, particularly in the context of flames involving combustible polyurethane foam insulation materials. The gas–liquid two-phase flow characteristics within Venturi tubes were investigated through numerical simulations using ANSYS-Fluent 2022 R1 software. This study focused on critical parameters, including the water inlet pressure (1–9 MPa), pharynx diameter (8–12 mm), contraction angle (15–45°), and expansion angle (15–45°). The average water mist droplet diameters at 1, 3, and 9 MPa were 169.890, 150.002, and 115.606 μm, respectively, in the absence of the Venturi tube, according to the experimental results. A reduction of up to 16.7% was achieved by reducing the particulate sizes to 141.462, 139.142, and 109.525 μm using the Venturi tube. The fire-extinguishing time and water consumption were substantially reduced at higher pressures, such as 9 MPa. Under high-pressure conditions, the results indicated that the Venturi microbubble technology was significantly more effective in suppressing fires. The novelty of this study lies in the application of Venturi microbubble technology to improve fine water mist systems for fire protection in cold storage facilities. This enhanced system achieves better atomization, uniform water mist distribution, faster cooling, and more efficient flame suppression, making it a viable solution for improving fire protection in such environments. Full article

Background: The postmortem diagnosis of fatal hypothermia presents a considerable challenge in forensic medicine. Metabolomics, a powerful tool reflecting comprehensive changes in endogenous metabolites, offers significant potential for exploring disease mechanisms and identifying diagnostic markers. Methods: In this study, we employed ultra-high-performance liquid chromatography–mass spectrometry (UHPLC–MS) to perform a non-targeted metabolomic analysis of liver, stomach, spleen, and musculus gastrocnemius tissues from mice subjected to fatal hypothermia. Result: A substantial number of differential metabolites were identified in each tissue: 1601 in the liver, 420 in the stomach, 732 in the spleen, and 668 in the gastrocnemius muscle. The most significantly altered metabolites were as follows: magnoflorine (liver, upregulated, ranked first in fold-change), gibberellic acid (stomach, downregulated, ranked first in fold-change), nitrofurantoin (spleen, upregulated, ranked first in fold-change), and isoreserpin (gastrocnemius muscle, downregulated, ranked first in fold-change). Glycerophospholipid metabolism exhibited notable enrichment in all tissues (spleen: second, liver: tenth, stomach: eleventh, gastrocnemius muscle: twenty-first), as did tryptophan metabolism (spleen: thirteenth, liver: eighth, stomach: third, gastrocnemius muscle: seventeenth). Conclusions: Our findings provide insights into the metabolic perturbations associated with fatal hypothermia in different tissues and lay a foundation for the identification of potential tissue biomarkers for forensic diagnosis. Full article

The greater wax moth (GWM, Galleria mellonella) is a prevalent pest of the honeybee and a significant risk to both honeybee populations and honeycomb storage. Research on the toxicity of essential oils (EOs) to GWM larvae has provided promising results, although their ovicidal effects and active ingredients require further study. Identifying effective plant compounds is essential for developing insecticides for GWM control. This study assessed the fumigation efficacy of 16 EOs on GWM eggs and fifth instar larvae and determined the effectiveness of these EOs and their primary components for fumigating fifth larvae. Wintergreen, star anise, and clove oils demonstrated significant insecticidal effects on GWM eggs and fifth instar larvae, resulting in a mortality rate exceeding 80% within 48 h. Gas chromatography-mass spectrometry analysis identified methyl salicylate (93.26%), trans-anethole (87.75%), and eugenol (77.75%) as the primary compounds in wintergreen, star anise, and clove oils, respectively. Further toxicity testing confirmed that these compounds were responsible for the observed insecticidal properties of the EOs. Notably, trans-anethole exhibited the lowest LC₅₀ value (25.22 μL/L) against the fifth instar larvae of GWM and significant toxicity against GWM eggs and fifth instar larvae, suggesting its potential as a viable option for the future control of GWM populations. Full article

We report a step-economic strategy for the direct synthesis of novel polycyclic N-heterocycle-fused naphthoquinones by merging intramolecular oxidative coupling and cascade [4 + 2] cycloaddition. In the protocol, mechanistic investigations suggest that the cascade reaction involves the intermediate spiro polycyclic N-heterocycles and [4 + 2] cycloaddition processes. This protocol is featured with moderate to excellent yields, wide substrate scope, and divergent structures of products. In addition, the photophysical properties of the synthesized products were evaluated. These products exhibit interesting fluorescence properties, and surprisingly, the compounds have the ability to selectively recognize trifluoroacetic acid. Full article

Biological soil crusts (biocrusts) promote plant growth by regulating soil nutrient dynamics and enhancing soil structure through the microorganisms they host. However, their impact on microbial nutrient limitation, a critical factor in nutrient cycling, remains underexplored. This study hypothesized that different types of biocrusts modulate soil nutrient limitations, influencing plant growth. A pot experiment was conducted to evaluate the effects of four treatments—control, diatom, Bacillus megatherium, and diatom–B. megatherium biocrusts—on soil structure, nutrient availability, microbial nutrient limitation, and ryegrass growth after 40 days of cultivation. The results indicated that the B. megatherium treatment exacerbated microbial C and N limitations and reduced available phosphorus (by 41.80%) and ryegrass biomass (by 29.19%) compared to the control. The diatom-B. megatherium treatment alleviated nutrient limitations but increased nutrient competition between soil microbes and plants, impairing plant performance. In contrast, the diatom treatment enhanced soil structure, alleviated microbial nutrient limitations, and significantly improved total capillary porosity (by 10%), available phosphorus (by 22.91%), saturated water content (by 21.81%), and ryegrass biomass (by 76.05%) while reducing soil bulk density (by 9.63%). These findings provide practical insights and a theoretical foundation for utilizing biocrusts to improve fluvo-aquic soil quality and promote sustainable plant growth. Full article

Eucalyptus cloeziana is an important, fast-growing, precious timber species in southern China, with tissue culture being the primary method for its propagation. However, the declining proliferation coefficient of adventitious shoots with multi-generation culture is a major constraint on its rapid propagation. This study aims to address this issue through the selection of suitable explants and optimizing the plant growth regulators’ formulation during the process of shoot proliferation. In this study, we cut shoots from the 21st generation of the tissue-cultured seedlings of ‘Chuanlinzhen 7523’ into apical, middle, and basal sections, and we measured their content of endogenous hormones. The proliferation coefficient (PC) and growth coefficient (GC) of explants under different concentrations of plant growth regulators were analyzed and ranked using the PCA method. The results indicated that the shoot basal sections were the best for proliferation when treated with 0.40 mg/L BAP (6-benzylaminopurine), 0.20 mg/L NAA (naphthaleneacetic acid), and 0.20 mg/L TDZ (thidiazuron), yielding a PC of 4.7 and a GC of 4.1. These basal sections ranked first with a rooting rate of up to 80%. When the rooted plantlets were acclimatized in the nursery, a survival rate of 100% was achieved. This protocol—from proliferation to acclimation—effectively improves the propagation efficiency of E. cloeziana ‘Chuanlinzhen 7523’ after multi-generation propagation. Full article