Search Results (9,018)

Iron-based Fischer–Tropsch synthesis (Fe-FTS) catalysts are central to coal-to-liquid (CTL) processes but suffer from rapid and complex deactivation under industrial conditions. This review critically examines the key deactivation mechanisms, including carbon/wax deposition, hydrothermal sintering, chemical poisoning (S, Cl, As), and mechanical attrition, and evaluates modern regeneration strategies. These strategies include supercritical fluid extraction for wax removal, controlled oxidative decoking, reductive reconstruction of active iron carbides (χ-Fe₅C₂), chemical de-poisoning, and structural upcycling. We also discuss emerging techniques such as non-thermal plasma and supercritical fluid-assisted reactivation. Finally, we highlight challenges in irreversible phase transformation, in -situ regeneration engineering, and economic feasibility, and outline future directions toward regeneration-friendly catalyst design and advanced syngas purification for a circular CTL economy. Full article

This paper reports new results on the synthesis and comparative characterization of cellulose nitrates (CNs) derived from Miscanthus × giganteus stems and from commercial microcrystalline cellulose (MCC). Miscanthus CNs synthesized by nitration with mixed sulfuric–nitric acids containing 16–20% water exhibit new functional properties: a high solubility in organic solvents (100% in acetone and 97–99% in alcohol–ether solvent) and a high viscosity (17–51 mPa·s), with a nitrogen content of 10.54–12.08 wt%. CNs from Miscanthus × giganteus are similar in nitrogen content and solubility to those from MCC (11.54% and 99%) but have a significantly greater viscosity (3 mPa·s), which is an undoubted advantage and considerably expands their potential application range. The solubility test of CNs synthesized from both sources demonstrated that Miscanthus CNs have a better film-forming ability. SEM analysis revealed a great difference in fiber length, despite the same cylindrical shape and observed aggregation: 1.0–2.0 mm for CNs from Miscanthus versus 40–60 μm for CNs from MCC. IR spectra of CNs from both sources showed the appearance of five new characteristic frequencies (1632–1633, 1273–1274, 823–826, 748, 677–686 cm^–1 for Miscanthus CNs and 1659, 1277, 832, 747, 691 cm^–1 for CNs from MCC), allowing the obtained compounds to be identified as nitric acid esters of cellulose. According to TGA/DTA analysis, the synthesized polymers have similarly high values of the onset temperature of both intense decomposition (197–198 °C) and narrow exothermic peaks (209–211 °C and 212 °C), respectively, indicating their high thermal stability. The combination of high solubility, viscosity, thermal stability and chemical purity of CNs derived from Miscanthus × giganteus stems suggests that strong thin films can be obtained and recommended for use in the manufacture of nitrocellulose membranes. Full article

The development of efficient and sustainable photothermal catalytic systems is pivotal for modern organic transformations. Herein, we report the rational design and solvothermal synthesis of NH₂-MIL-101(Fe) metal–organic frameworks (NM-101) integrated with carbon nanotubes (CNTs) for the photothermal reduction in nitronaphthalene. The optimized NM-101/75C composites exhibit exceptional catalytic activity and high selectivity under NIR light irradiation, delivering a high yield of 84.4% within 1 h, which significantly outperforms its individual components. Systematic control experiments and detailed spectroscopic investigations reveal a powerful synergistic effect at the MOF-CNT interface, where the CNTs play a dual role in augmenting light harvesting and facilitating charge carrier separation. Furthermore, the high photothermal conversion efficiency of the composite enables rapid reaction kinetics. This work provides a robust and scalable strategy for constructing high-performance photothermal catalysts, offering critical insights into the interfacial engineering of MOF-based materials for industrial chemical manufacturing. Full article

The formation of carbon nanostructures and silicon carbide (SiC) using a single-source precursor offers a simplified route for material synthesis; however, the factors governing the transition between CNT-like structure formation and SiC growth remain unclear. In this study, the growth behavior of carbon-related structures using vinylsilane was systematically investigated by hot-wall chemical vapor deposition (CVD) on various substrates, including Fe bulk substrates and Fe thin films on SiO₂/Si. CNT-like structures were preferentially formed on Fe bulk substrates, whereas Fe thin-film substrates exhibited CNT-like growth at the initial stage followed by increased Si–C-related phase formation with increasing growth temperature and growth time. In contrast, on Fe thin films with limited catalyst amounts, CNT-like growth occurred initially, followed by increased Si–C-related phase formation with increasing growth temperature and growth time. These observations are consistent with a growth transition associated with the balance between Si uptake into the metal and surface SiC formation processes. By controlling catalyst amount, growth temperature, and growth time, the relative formation of CNT-like structures, SiC-rich coatings, and intermediate morphologies could be tuned within a single process. Furthermore, a SiC/CNT-like composite structure was directly formed on a conductive Fe substrate in a one-step CVD process. Electrochemical measurements showed an enhanced current response compared with a bare Fe substrate, indicating preliminary electrochemical activity and suggesting potential applicability as a high-surface-area electrode platform. Full article

Ribosomes are essential macromolecular complexes responsible for protein synthesis and have traditionally been regarded as uniform and passive components of translational machinery. However, accumulating evidence has revealed that ribosomes exhibit substantial heterogeneity in both composition and function. In this review, we summarize the major sources of ribosome heterogeneity in plants, including ribosomal protein (RP) paralog diversity, sequence variation in rDNA/rRNA, dynamic chemical modifications of rRNAs and RPs, alterations in RP stoichiometry, and the involvement of ribosome-associated factors. These mechanisms collectively generate structurally and functionally distinct ribosome populations. Emerging evidence suggests that these heterogeneous ribosomes can actively regulate gene expression by preferentially translating specific subsets of mRNAs in response to developmental cues and environmental conditions. We further discuss the potential biological implications of ribosome heterogeneity in plant growth, development, and stress adaptation, and highlight current challenges in the field. Advances in high-resolution structural and single-ribosome profiling technologies are expected to provide new insights into the regulatory roles of heterogeneous ribosomes. This review provides a comprehensive framework for understanding the causes and functional significance of ribosome heterogeneity in plants, offering new perspectives on translational regulation and plant adaptive biology. Full article

Per- and polyfluoroalkyl substances (PFAS) are ultra-persistent contaminants characterized by exceptional chemical stability, high mobility, and widespread environmental occurrence, posing significant challenges for remediation. Phytotechnology has emerged as a promising nature-based approach, yet its effectiveness is strongly governed by PFAS physicochemical properties and plant–soil interactions. This review provides a mechanistic synthesis linking PFAS environmental behavior with phytotechnology performance by examining PFAS sources, transport pathways, and structure-dependent properties that control persistence, partitioning, and mobility, with an emphasis on differences between short- and long-chain compounds. These characteristics determine bioavailability and influence treatment outcomes. Plant uptake mechanisms, including root absorption, xylem translocation, and tissue accumulation, are discussed alongside rhizosphere processes such as sorption, microbial interactions, and hydrological dynamics that regulate PFAS retention and redistribution. Current evidence indicates that phytotechnology functions primarily as a form of phytomanagement rather than a destructive solution, as mineralization is limited and field-scale treatment remains low. Instead, plant–soil–microbe systems reduce PFAS mobility and exposure through stabilization and sequestration. Future research should prioritize strategies for short-chain PFAS, integration with sorptive amendments, and data-driven approaches to optimize phytomanagement performance. Full article

Antibiotic resistance has emerged as a major global health challenge, underscoring the urgent need for alternative therapeutic strategies capable of enhancing the efficacy of existing antibiotics. In this context, saponin-based nanomaterials have attracted considerable attention due to their potential as antibiotic-modulating systems. This study investigated a saponin-enriched fraction obtained from the bark of Sarcomphalus joazeiro Mart. (SEF-4), its application in the green synthesis of silver nanoparticles, and the antibiotic-modulating potential of the resulting nanoformulation. SEF-4 was obtained from the ethanolic bark extract through liquid–liquid partitioning (52% yield), followed by column chromatographic purification and chemical characterization using LC-ESI-QTOF-MS. The purified fraction was subsequently employed as both a reducing and stabilizing agent for the synthesis of silver nanoparticles (putative AgNP-SEF-4), which were physicochemically characterized. Antibacterial activity and antibiotic-modulating effects were evaluated using the broth microdilution method against standard and multidrug-resistant bacterial strains. LC-ESI-QTOF-MS analysis enabled the putative identification of five jujubogenin-type triterpenoid saponins bearing tetra-, penta-, and hexasaccharide moieties with distinct glycosylation profiles; however, the precise sugar sequence, monosaccharide composition, and glycosidic linkage positions remain to be confirmed through complementary NMR and hydrolysis studies. Although neither SEF-4 nor putative AgNP-SEF-4 displayed clinically relevant intrinsic antibacterial activity, the nanoformulation significantly enhanced the activity of aminoglycoside antibiotics. The most pronounced modulatory effects were observed against Klebsiella pneumoniae ATCC 1705 in combination with amikacin and against both standard and multidrug-resistant Escherichia coli strains when combined with gentamicin or amikacin. These findings highlight the potential of putative AgNP-SEF-4 as an antibiotic adjuvant capable of potentiating aminoglycoside efficacy and increasing bacterial susceptibility, including in multidrug-resistant strains. Full article

RNA interference (RNAi) represents a promising alternative to chemical insecticides, but its efficacy depends on efficient double-stranded RNA (dsRNA) uptake, a process poorly characterized in thrips. To enable sufficient dsRNA production for functional studies, we first optimized an E. coli expression system by constructing a vector containing three tandem terminators, which substantially enhanced dsRNA yield by approximately 11-fold. Using this optimized production system, this study identified a conserved muscle actin fragment for dsRNA synthesis and evaluated RNAi responses in Megalurothrips usitatus and Frankliniella occidentalis. Insect mortality, target-gene suppression, and transcriptomic responses were evaluated via RT-qPCR and RNA-seq analyses using artificial diets supplemented with muscle actin dsRNA. The designed dsactin shared > 97% sequence identity between the two species. Oral ingestion of 1500 ng µL⁻¹ dsRNA caused concentration-dependent mortality (72% in M. usitatus, 48% in F. occidentalis) and significant down-regulation of muscle actin mRNA within 72 h. Transcriptomic analysis in M. usitatus revealed upregulation of genes associated with clathrin-mediated endocytosis and SID-1-like transmembrane transport, suggesting a potential dual-pathway model for dsRNA uptake. These findings provide correlative insights into RNAi efficiency in thrips. Full article

MXenes, a rapidly expanding family of two-dimensional transition-metal carbides and nitrides, are increasingly viewed as strong candidates for defense-oriented multifunctional systems because they combine metallic conductivity, surface tunability, mechanical flexibility, and solution processability within a lightweight platform. Unlike conventional metals, ceramics, and semiconductors, which usually optimize one or two parameters at the expense of density, brittleness, or integration compatibility, MXenes offer a rare opportunity to coordinate electromagnetic, mechanical, thermal, and sensing functions within one material family. Different from existing reviews that focus on laboratory-level record performance or single-function optimization, this review presents an innovative deployment-oriented perspective and fills the research gap of systematic military-oriented evaluation for MXenes. In this review, we examine MXenes from a deployment-oriented perspective rather than through isolated record values. We first summarize their formation chemistry and major synthesis routes, including HF and in-situ HF etching, bifluoride and alkaline methods, molten-salt strategies, electrochemical approaches, and precursor-free chemical vapor deposition. We then discuss the principal levers of property regulation, focusing on composition design, surface-termination control, and heterostructure engineering, and show how these strategies shape the performance envelopes relevant to shielding, stealth, impact response, energy storage, and sensing. This review constructs a full-chain analytical framework from synthesis, property regulation to military application and deployment challenges for the first time. Finally, we identify the main barriers to translation, especially manufacturing inconsistency, termination heterogeneity, oxidation and interfacial degradation, and limited application-level validation, and outline the most realistic paths toward deployable defense technologies. Full article

Most traditional photocatalysts exist in powder form and have the disadvantage of being difficult to recycle and causing secondary pollution to the environment after use. To overcome this drawback, this study combined natural biopolymer (silk fibroin (SF)) with a previously developed titanium-based photocatalytic material P/Ag/Ag₂O/Ag₃PO₄/TiO₂ (PAgT) and fabricated a novel SF/PAgT fiber membrane via electrospinning. During the synthesis process, through adjusting the mass concentration of the PAgT dopant (0–0.30 g/mL), a series of photocatalytic fiber membranes were prepared. The morphology and structure of the as-prepared membranes were characterized by various analytical methods, including scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR), contact angle (CA) and thermogravimetric analysis (TGA). The SEM images confirmed that the SF/PAgT composite membrane possessed a protrusive and spindle-shaped structure. FT-IR results verified that the primary structure of SF in all the as-prepared SF/PAgT membranes belonged to the Silk II type. The binding of SF with the PAgT photocatalyst did not disrupt the chemical structure and original properties of SF. Moreover, the XRD and CA measurements indicated that the SF/PAgT-4 fiber membrane exhibited the stronger diffraction peaks of anatase TiO₂ crystal structure and enhanced hydrophilicity. The experimental results clarified that the PAgT photocatalyst was successfully loaded onto the SF fiber membrane by electrospinning. To evaluate the performance of the developed visible-light-driven photocatalytic fiber membranes, Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus) were selected as representative bacteria strains. The results demonstrated that SF/PAgT-4 exhibited the optimal antibacterial activity and can completely inactivate 10⁷ CFU/mL of E. coli and S. aureus within just 30 min and 60 min treatment, respectively, indicating the optimal doping mass concentration of PAgT during the synthesis process was 0.20 g/mL. Furthermore, the scavenger study proved that during the photocatalytic disinfection process by SF/PAgT-4, all three radicals, including ·OH, h⁺ and ·O₂⁻, participated in the current photocatalytic disinfection system. They were capable of attacking the bacterial cells, causing the cell membrane injury, thereby leading to the intracellular component leakage and inducing extensive bacterial inactivation. Hence, by virtue of its excellent recyclability (during five cycles) and thermal stability (below 250 °C), the developed SF/PAgT-4 fiber membrane holds immense potential for highly efficient and sustainable utilization in practical water treatment applications. Full article

The shoots of ‘Ziyan’ (Camellia sinensis (L.) O. Kuntze) are rich in anthocyanins, making their flavor unique and providing health benefits. The problem is that ‘Ziyan’ has weak growth and low yield of the shoots. Nitrogen levels affect the yield and quality of tea shoots by regulating their growth and the metabolism of major quality components, but the underlying mechanism remains unclear. In this study, one-year-old seedlings of purple cultivar ‘Ziyan’ (Camellia sinensis) were grown hydroponically under three nitrogen levels (low nitrogen, moderate nitrogen, high nitrogen). The contents of quality-related chemical components and key enzyme activities were determined, combined with transcriptome analysis, to investigate the effects of nitrogen level on growth and quality component metabolism of ‘Ziyan’ tea seedlings. Results showed that compared with medium nitrogen (control), low nitrogen significantly decreased yield and total free amino acids, while high nitrogen did not markedly increase either index. Meanwhile, both low and high nitrogen significantly elevated phenylalanine content by 132.46% and 47.37%, respectively. Although the responses of EGCG and catechin contents to low nitrogen and high nitrogen are completely opposite. However, both low nitrogen and high nitrogen significantly reduced the anthocyanin content in shoots (8.15%, 25.26%), inhibiting anthocyanin synthesis. Kyoto Encyclopedia of Genes and Genome (KEGG) enrichment analysis revealed that flavonoid, phenylpropanoid and sucrose-related pathways were relatively active under both high and low nitrogen supply. Additionally, transcriptome analysis identified C4H, LAR and FLS as key genes, and transcription factors (e.g., GRF, bHLH, MYB) and auxins were actively involved in the nitrogen stress response related to ‘Ziyan’ shoot growth and major quality component metabolism. The findings help clarify the adaptive mechanisms of ‘Ziyan’ shoots under nitrogen stress and provide a scientific basis for the fertilization management. Full article

The removal of recalcitrant industrial dyes from wastewater has emerged as a critical environmental challenge, particularly in the context of the accelerating decline of global freshwater reserves. Given that these contaminants originate predominantly from the effluents of textile, chemical, and related manufacturing sectors, the deployment of advanced treatment technologies prior to discharge is imperative to mitigate their ecological impact. This study investigates the photocatalytic degradation of indigo carmine using a synthesized MgAl–LDH material. LDH is shown to act as an active photocatalytic component rather than a support, with its remarkably simple synthesis offering a practical alternative to the complex catalysts dominating the current literature. The catalyst’s structural, morphological, and surface characteristics were comprehensively validated through XRD, SEM, EDX, and BET analyses. The catalyst was evaluated under varying hydrogen peroxide doses and across an initial dye concentration range of 5 × 10⁻⁵ to 5 × 10⁻⁴ M. Increasing the H₂O₂ volume (3.5–20 mL, corresponding to H₂O₂ excess ratios of 17.5–100) significantly enhanced the oxidation rate, whereas higher dye concentrations reduced efficiency due to photon competition and partial saturation of catalytic sites. These experiments provided the basis for extracting kinetic parameters and assessing the mechanistic pathways governing the photocatalytic process. The kinetic behavior of indigo carmine degradation was evaluated by fitting the experimental data to zero-order, first-order, and second-order empirical models to identify the rate law that best describes the reaction. Reusability tests showed that MgAl–LDH maintains high activity over multiple cycles, with only a moderate decline, demonstrating its stability and suitability for practical wastewater treatment applications. Full article

Atractylodes chinensis (DC.) Koidz is a pharmacologically significant medicinal plant that produces various bioactive metabolites, including β-eudesmol, which largely determines its medicinal quality and clinical efficacy. Treatment of A. chinensis hairy roots with 5-methoxyindole (5-MI), a chemical homolog of melatonin, revealed that 0.5 mmol·L⁻¹ 5-MI significantly enhanced β-eudesmol production. To investigate the underlying mechanism, we performed integrated transcriptomic and metabolomic analyses. Comprehensive targeted metabolomics identified ten upregulated terpenoids among the differentially expressed metabolites following 5-MI treatment in A. chinensis hairy roots, including β-eudesmol. The 5-MI treatment significantly influenced the expression levels of genes associated with metabolic regulation and secondary metabolite synthesis in A. chinensis hairy roots, particularly promoting the upregulation of genes involved in terpenoid biosynthesis. Notably, a putative sesquiterpene synthase gene, AcTPS1, was significantly upregulated after 5-MI treatment and was a strong candidate gene correlated with β-eudesmol. AcTPS1 belongs to the TPS-a subfamily and exhibits tissue-specific expression, with high transcript levels in root tissues, especially in one-year-old roots of A. chinensis. This study demonstrates that 5-MI serves as an effective elicitor, providing valuable insights for the production of medicinally active compounds and enhancing our understanding of the molecular mechanism by which 5-MI regulates plant secondary metabolism. Full article

Silicon carbide (SiC) nanowires possess unique one-dimensional structural features, excellent mechanical strength, thermal stability and wide bandgap properties, showing great potential in high-temperature electronics, catalysis, sensing and composite reinforcement. Nevertheless, pristine SiC nanowires suffer from inert surface activity, weak interfacial compatibility and limited optoelectronic and catalytic performance. Surface coating and heterojunction engineering are effective strategies to address these deficiencies. This review systematically summarizes the synthesis routes of pristine SiC nanowires, including carbothermal reduction, chemical vapor deposition, template-assisted growth and molten salt synthesis, as well as their morphological regulation, physicochemical properties and inherent limitations. Meanwhile, typical coating methods such as wet chemical, hydrothermal, CVD and PIP are elaborated, and the influences of coating thickness, uniformity, adhesion and lattice/thermal compatibility on performance are summarized. The classification and interfacial charge mechanism of Type II, Z-scheme and Schottky heterojunctions are discussed, and the advances of coated SiC nanowires in photodetection, photocatalysis, gas sensing, electromagnetic shielding and energy storage are reviewed. Current challenges including coating stability, scalable preparation and integration bottlenecks are pointed out, and future research directions focusing on interface control, multifunctional integration and AI-assisted material design are prospected. Full article

Biocatalysis has emerged as a mainstay in the field of sustainable chemical synthesis owing to its high selectivity, mild reaction conditions, and reduced environmental impact. Traditional enzyme engineering approaches, such as rational design and directed evolution, are often associated with limited throughput and a limited understanding of sequence–structure–function relationships, despite high experimental costs. In recent years, the integration of machine learning (ML) into enzyme engineering has emerged as a transformative approach, enabling data-driven prediction, design, and optimization of biocatalysts, thereby enhancing performance and applications. This review provides a comprehensive overview of ML-guided strategies to improve key enzymatic parameters, including the turnover number (k_cat), substrate affinity (K_m), and catalytic efficiency (k_cat/K_m), with a focus on mechanistic insights and performance outcomes. The integration of ML models into design–build–test–learn (DBTL) cycles accelerated directed evolution, reduced screening efforts, and enabled targeted mutagenesis. Beyond applications, this review also discusses the current limitations of ML-guided approaches, including data scarcity, model interpretability, and challenges in predicting complex mutations and allosteric effects. The gap between computational predictions and experimental outcomes is identified, and the role of ML integration with enzyme kinetics, molecular dynamics, and high-throughput experimentation is emphasized. Future directions, such as generative AI, explainable ML, and autonomous laboratories, are discussed for next-generation biocatalytic applications. Full article