Search Results (20,191)

High denitration efficiency and strong adaptability to flue gas temperature fluctuations are the core properties of the NH₃-SCR catalyst. In this study, Fe₂O₃ modification is used as a means to explore the mechanism of adding Fe₂O₃ to broaden the temperature range of the 6CeO₂-40MnO₂/TiO₂ catalyst during the preparation process. The results show that the 6Fe₂O₃-6CeO₂-40MnO₂/TiO₂ catalyst exhibits excellent denitration performance, with a denitration efficiency higher than 90%. The temperature range is from 129 to 390 °C. N₂ selectivity and resistance to SO₂ and H₂O are good, and the denitration performance is significantly improved. When the Fe₂O₃ content is 6%, it promotes lattice shrinkage of TiO₂, improves its dispersion, refines the grain size, and increases the specific surface area of the catalyst. At the same time, Fe₂O₃ enhances the chemical adsorption of oxygen on the catalyst surface and increases the proportion of low-cost metal ions, thereby promoting electron transfer between active elements, generating more surface reactive oxygen species, increasing the oxygen vacancy content and adsorption sites for NO_x and NH₃, and significantly improving the redox performance of the catalyst. This effect is particularly conducive to the formation of strong acid sites on the catalyst surface. The NH₃-SCR reaction on the surface of the 6Fe₂O₃-6CeO₂-40MnO₂/TiO₂ catalyst follows both the L-H and E-R mechanisms, with the L-H mechanism being dominant. Full article

Ginger is a common spice found in many cuisines all over the world that is from the rhizome of Zingiber officinale. Additionally, it has been used in traditional medicinal practices as an aid in many ailments ranging from nausea to muscle pain. The non-volatile compounds of ginger, including zingerone, are responsible for pungency and they have widespread biomedical activities. The crystal structure of zingerone, a 6-gingerol degradation product and phenolic compound, reveals that the C4 hydroxyl group is the fulcrum for strong intermolecular interactions such as (O1-H2…O3) 2.737(2) Å. Our electrochemical results using rotating ring-disk electrode (RRDE) hydrodynamic voltammetry demonstrate that zingerone is an effective scavenger of superoxide radical anions and that zingerone, unlike powdered ginger, is a strong antioxidant with a collection efficiency slope of −6.5 × 10⁴ M⁻¹. The addition of vitamin C enhances scavenging activity for both zingerone and ginger powder, although the effect is more noticeable with zingerone. Correspondingly, the zingerone/vitamin C efficiency slope value is −5.40 × 10⁵ M⁻¹. Density Functional Theory (DFT) calculations permit the development of a plausible antioxidant mechanism for zingerone, and zingerone synergistic action with vitamin C, in which zingerone is capable of being regenerated with the assistance of protons that may be provided by ascorbic acid. This mechanism demonstrates that zingerone acts as a strong antioxidant agent by virtue of its C4 hydroxyl group and aromatic system. The scavenging chemical reaction is the same as that obtained through the dismutation of superoxide by superoxide dismutase (SOD) enzymes into hydrogen peroxide and molecular oxygen. Thus, zingerone behaves as a SOD mimic. Full article

In recent years CO₂ reforming of methane has attracted great interest as it produces high CO/H₂ ratio syngas suitable for the synthesis of higher hydrocarbons and oxygenated derivatives since it is a way for disposing and recycling two greenhouse gases with high environmental impact, CH₄ and CO₂, and because it is regarded as a potential route to store and transmit energy due to its strong endothermic effect. Along with noble metals, all the group VIII metals except for osmium have been studied for catalytic CO₂ reforming of methane. It was found that the catalytic activity of Ni, though lower than those of Ru and Rh, was higher than the catalytic activities of Pt and Pd. Although noble metals have been proven to be insensitive to coke, the high cost and restricted availability limit their use in this process. It is therefore valuable to develop stable Ni-based catalysts. In this contribution, we show how their activity and coking resistivity are greatly related to the size and dispersion of Ni particles. Well-dispersed Ni nanoparticles were achieved by multistep impregnation on a mesoporous silica support, namely SBA-15, obtained through a sol-gel method, using acetate as a nickel precursor and keeping the Ni loading between 5% and 11%. Significant catalytic activity was obtained at temperatures as low as 450 °C, a temperature well below their deactivation temperature, i.e., 700 °C. For the pre-reduced samples, a CO₂ conversion higher than 99% was obtained at approximately 680 °C. As such, their deactivation by sintering and coke formation was prevented. To the best of our knowledge, no Ni-based catalysts with complete CO₂ conversion at temperatures lower than 800 °C have been reported so far. Full article

Lignin constitutes a fundamental component of plant defense mechanisms against environmental stressors. 4-coumarate 3-hydroxylase (C3H) serves as a pivotal enzyme in lignin biosynthesis. However, its role in the halophyte Sesuvium portulacastrum remains uncharacterized. In this study, the SpC3H gene was cloned, and subsequent sequence alignment and phylogenetic analyses revealed the highest similarity (57.14%) with BvC3H from Beta vulgaris, exhibiting the closest evolutionary relationship with Beta vulgaris and Spinacia oleracea C3H protein. Quantitative real-time polymerase chain reaction demonstrated that SpC3H expression was markedly upregulated in both roots and leaves of S. portulacastrum under 800 mM NaCl treatment. Root expression peaked at 48 h (25.3-fold), whereas leaves displayed dual expression maxima at 12 h (7.9-fold) and 72 h (10.7-fold). Subcellular localization assays confirmed cytoplasmic distribution. Heterologous expression in Arabidopsis thaliana indicated that transgenic lines exhibited enhanced growth performance, higher fresh weight, and elevated lignin contents relative to wild-type plants under salt stress, accompanied by reduced reactive oxygen species (ROS) accumulation and lower relative electrical conductivity. Furthermore, activities of superoxide dismutase and peroxidase, together with expression of lignin biosynthesis-associated and antioxidant enzyme genes, were markedly elevated. Collectively, these findings establish that SpC3H confers salt tolerance by promoting lignin biosynthesis and activating antioxidant defenses to eliminate ROS, thereby providing a theoretical foundation for genetic improvement of plant salt tolerance. Full article

In this study, thermogravimetric analysis (TGA) was coupled with Fourier-transform infrared (FTIR) spectroscopy to systematically investigate the pyrolysis characteristics and mechanisms of cement fiberboard across varying heating rates. Experimental findings demonstrated that the thermal degradation process occurs in four distinct phases. Overlapping decomposition peaks in DTG curves were successfully resolved using a double-Gaussian deconvolution algorithm. A comprehensive kinetic analysis was conducted by integrating model-free iso-conversional methods (Flynn–Wall–Ozawa and Kissinger–Akahira–Sunose analysis) with a model-fitting technique (Coats–Redfern approximation) to determine the activation energies for each degradation stage. A subsequent FTIR spectroscopic analysis revealed that the evolution of gaseous products follows the sequence CO₂ > H₂O > CH₄. The CO₂ release was found to originate from multiple pathways, including the decomposition of organic components and high-temperature inorganic reactions. Notably, while the heating rate had a negligible impact on product speciation, it exhibited a statistically significant influence on CO₂ emission intensities. Finally, mechanistic interpretations integrating Arrhenius parameters with time-resolved infrared spectral features were proposed for each thermal decomposition stage. Full article

In vitro maturation (IVM) of oocytes is a pivotal step in assisted reproductive technologies for livestock. However, oxidative stress (OS) and mitochondrial dysfunction during in vitro culture often lead to oocyte aging, thereby limiting the efficiency of the technologies. To address these challenges, this study investigated the regulatory effects of 1-Palmitoyl-2-Oleoyl-sn-Glycero-3-Phosphocholine (POPC) on bovine oocyte IVM, aging, and developmental competence to determine the optimal concentration and explore underlying mechanisms. Cumulus–oocyte complexes (COCs) were collected from abattoir-derived bovine ovaries and cultured in IVM medium supplemented with 0 (control), 50, 100, 150, or 200 μmol/mL of POPC (n = 300 per group) at 38.5 °C under 5% CO₂ for 22 h. The optimal concentration was determined based on the first polar body extrusion rate, followed by in vitro fertilization (IVF), fluorescence staining, Smart-seq2 transcriptome sequencing, and quantitative PCR (qPCR) analysis. The results demonstrated that 150 μmol/mL of POPC yielded the highest maturation rate, significantly exceeding the control group (p < 0.05), and enhanced 2-4-cell cleavage rates after IVF. Furthermore, POPC markedly reduced intracellular reactive oxygen species (ROS) levels, increased glutathione (GSH) content, improved mitochondrial function, and restored normal spindle morphology. Transcriptomic analysis identified 350 upregulated and 280 downregulated differentially expressed genes (DEGs), which were enriched in pathways related to OS. qPCR validation confirmed upregulation of SIRT1/2 and BCL-2, along with downregulation of BAX and Caspase-1/3. Collectively, these findings suggest that 150 μmol/mL of POPC alleviates OS and activates the “SIRT–antioxidant–antiapoptotic” signaling axis, thereby providing valuable insights for optimizing assisted reproductive technologies in livestock. Full article

Two-component systems (TCSs) in bacteria are often involved in the global regulation of various physiological activities and behaviours. This study investigated the GacSA TCS and DJ41_1407 transcriptional sensor adjacent to GacA in Acinetobacter baumannii ATCC 19606. The relationship between GacS, GacA, and DJ41_1407 and their functions and signal transduction mechanisms are described. A. baumannii ATCC 19606 mutants, ∆gacS, ∆gacA, and ∆DJ41_1407, were generated using markerless mutation and cultured in LB medium, then collected for RNA sequencing. It was found that GacS, GacA, and DJ41_1407 regulate a series of genes involved in carbon metabolism. Quantitative reverse transcription PCR (qRT-PCR) results showed that DJ41_1407 and GacA may regulate the expression of adh4, ipdC, iacH, and paa. Phos-tag™ results revealed that GacS plays a more significant role in GacA phosphorylation. GacA regulated colony size and growth conditions in rich medium. Compared to the wild-type strain, the ∆gacA and ∆gacSA mutants exhibited smaller colony sizes, and mutation of the gacS, gacA, and DJ41_1407 genes also reduced bacterial virulence as determined by the Galleria mellonella infection assay. GacA also plays a crucial role in modulating antibiotic resistance, and the ∆gacA∆DJ41_1407 mutant demonstrated greater susceptibility to antibiotics. These results highlight the multiple functions regulated by the GacSA global TCS in A. baumannii ATCC 19606. Full article

Hericium coralloides is a valuable medicinal and edible mushroom renowned for its unique bioactive compounds. This study focuses on the isolation of a wild strain (SH001) exhibiting promising cultivation potential and health promoting properties. A wild fungal strain from the Tibetan Plateau was isolated and identified as a novel H. coralloides based on its morphological and molecular characteristics. The optimal growth conditions were found to be 30 °C, pH 7.0, fructose as the preferred carbon source, and yeast extract as the optimal nitrogen source. Nutritional analysis revealed that the fruiting bodies were rich in protein (15.4 g/100 g dry weight), dietary fiber (34.7 g/100 g dry weight), and minerals, while being low in fat (3.5 g/100 g dry weight). The most abundant amino acids were glutamic acid, followed by aspartic acid. The polysaccharides exhibited significant antioxidant activity, with ABTS⁺ scavenging comparable to that of Vitamin C (Vc), achieving a clearance rate of 96.95% at concentrations between 0.25–5.00 mg/mL. At a concentration of 5 mg/mL, the DPPH and OH radical scavenging activities reached their peak (83.77% and 67.31%, respectively), along with the highest iron ion reducing capacity (FRAP value: 4.43 mmol/L. Polysaccharides also exhibited notable anticancer activity, inhibiting HepG2 liver cancer cells and MDA-MB-468 breast cancer cells, with IC₅₀ values of 3.896 mg/mL and 2.561 mg/mL, respectively. This study demonstrates that wild H. coralloides can be successfully cultivated in vitro. In conclusion, the fruiting bodies possess substantial nutritional value, and the polysaccharides extracted from them show promising antioxidant and anticancer activities, particularly against HepG2 liver cancer cells and MDA-MB-468 breast cancer cells. Full article

Feijoa (Acca sellowiana Berg) is an emerging Mediterranean crop valued for its nutraceutical potential but still underexplored with respect to cultivar and harvest stage. This study investigated two cultivars, ‘Mammoth’ and ‘Apollo’, harvested one week apart (4 and 11 November), to assess morphological traits, phenolic composition, antioxidant activity, vitamin C, and iodine. Fruit morphology, firmness, and basic quality indices (TSS, TA, pH, TSS/TA) were determined, while phenolic compounds were profiled by UHPLC–Q-Orbitrap HRMS. Antioxidant activity was measured by ABTS, DPPH, and FRAP assays; vitamin C by DCPIP titration; and iodine by iodometric analysis. ‘Apollo’ produced larger and firmer fruits, especially at the first harvest (105.6 g), while ‘Mammoth’ showed smaller and softer fruits. TSS remained stable (11 °Brix), whereas TA decreased and pH increased over time, raising the TSS/TA ratio and suggesting improved flavor balance at later harvests. Peel consistently contained higher bioactive levels than pulp, with catechin as the dominant phenolic compounds (up to 345 µg g⁻¹ dw in ‘Apollo’ peel). Antioxidant activity was markedly higher in peel, with ‘Mammoth’ showing stronger early FRAP values and ‘Apollo’ increasing at the later harvest. Vitamin C and iodine were about threefold higher in peel than pulp and increased over time, reaching maxima in late-harvest peel samples. Overall, cultivar and harvest stage significantly influenced fruit quality and nutraceutical value. Peel, particularly that of late-harvested ‘Apollo’, represents a promising resource for functional foods and the valorization of processing by-products. Full article

Foodborne illnesses associated with Bacillus cereus represent a persistent public health concern. In this study, we described the isolation and characterization of a novel bacteriophage, ΦBc24, from mud samples, which showed lytic activity against foodborne pathogen B. cereus. Transmission electron microscopy revealed that ΦBc24 exhibited a myovirus morphotype. Biological assays demonstrated that its narrow host range was restricted to B. cereus strains and efficient lytic activity, characterized by a latent period of 10 min and a burst size of 40 PFU per infected cell. The phage exhibited high physicochemical stability, tolerating pH values of 2–12, temperatures of 4–50 °C, salinity up to 1 M NaCl, and ultraviolet exposure, while effectively suppressing host bacterial growth for up to six hours. Whole-genome sequencing showed that phage ΦBc24 possessed a double-stranded DNA genome of 160,311 bp, with 39.48% GC content, and 269 predicted open reading frames (ORFs). Remarkably, 11 tRNA genes were identified, whereas no genes associated with lysogeny, virulence, or antimicrobial resistance were detected. Phylogenetic analysis suggested that ΦBc24 belongs to the genus Caeruleovirus, subfamily Bastillervirinae, family Herelleviridae. Taken together, these results highlight the biological robustness and genomic safety of ΦBc24, supporting its potential as a biocontrol candidate against the foodborne pathogen B. cereus. Full article

Diabetic foot ulcers (DFUs) and other chronic wounds are major global health challenges, often complicated by infections and delayed healing due to excessive collagen accumulation. Microbial collagenases offer an enzymatic alternative to surgical debridement by selectively degrading collagen and potentially limiting microbial colonization. In this study, an isolated and characterized thermostable collagenase from Streptomyces scabies from rhizospheric soil in Al-Lith thermal springs, Saudi Arabia, is investigated. Identification was confirmed via 16S rRNA sequencing, and enzyme production was optimized on gelatin agar. Partial purification was achieved through ammonium sulfate precipitation and dialysis, and molecular weight (~25 kDa) was determined by Sodium dodecyl sulfate–polyacrylamide gel electrophoresis. Activity was assessed under varying temperatures, pH, substrates, and metal ions, while antibacterial potential was tested against Staphylococcus aureus, Klebsiella pneumoniae, and Pseudomonas aeruginosa. The collagenase exhibited optimal activity at 80 °C and pH 9, stability under thermophilic and alkaline conditions, activation by Fe²⁺, and notable antibacterial effects at higher concentrations. These results demonstrate that S. scabies collagenase exhibits selective antibacterial activity in vitro, suggesting its potential as an enzymatic tool for further evaluation in diabetic foot debridement and infection control. Full article

This study investigates the control of the phase-structural state in Ni–45Ti–xCu (x = 5, 7 at.%) shape memory alloys fabricated via a shortened powder metallurgy route: mechanical activation → spark plasma sintering (SPS) → heat treatment. Compact samples were produced from mechanically alloyed powders (650–750 rpm, up to 5 h) and sintered at 900 °C. The structure and microstructure were characterized using X-ray diffraction (to identify B2/B19′/Ni₄Ti₃ phases and assess ordering) and SEM–BSE/EDS (to analyze morphology, porosity, and Ni-rich precipitates). Two post-processing treatments were applied: single-stage annealing (500 °C, 2 h) and a three-stage treatment (900 °C/30 min → water quenching → 300 °C/20 min). Mechanical alloying transformed the initial elemental powder mixture (fcc-Ni, hcp-Ti, fcc-Cu) into a supersaturated fcc-(Ni, Cu, Ti) solid solution with emerging NiTi phases, with a minimum particle size achieved after ~300 min at 750 rpm. SPS compaction yielded a high-density matrix consisting predominantly of the B2 phase. Single-stage annealing preserved B19′ martensite and Ni₄Ti₃ precipitates, particularly in the 5 at.% Cu alloy. In contrast, the three-stage treatment dissolved the Ni₄Ti₃ precipitates, suppressed the formation of B19′ and R phases, and stabilized a highly ordered B2 matrix. Increasing the Cu content from 5 to 7 at.% significantly enhanced the B2 phase fraction, reduced secondary nickel-rich phases, and improved structural homogeneity, evidenced by a continuous neck network and closed porosity. The optimized condition—7 at.% Cu combined with the three-stage annealing—produced a microstructure with >95% B2 phase, <1% Ni₄Ti₃, and ~98% relative density. This forms the prerequisite microstructural state for a narrow transformation hysteresis and high functional cyclic stability. Full article

The degradation of municipal solid waste (MSW) in landfills involves complex physical, chemical, and biological interactions that span multiple spatial and temporal scales. To better understand these dynamics, this study develops a comprehensive model that couples microbial, chemical, thermal, and hydraulic fields. The model captures bidirectional feedback mechanisms, such as heat and acid production from microbial metabolism, which in turn influence microbial activity and reaction pathways. A simplified one-dimensional formulation was solved using the finite difference method and validated against historical temperature data from real landfills. Simulation results indicate that temperature peaks at approximately 45 °C around the fifth year, followed by a gradual decline. pH and substrate concentration decrease over time but exhibit minimal variation with depth. The degradation rate reaches its maximum within two years and subsequently declines. These trends highlight the critical roles of temperature in initiating rapid degradation and substrate concentration in determining the endpoint of the reaction. This model provides a theoretical foundation for interpreting energy and mass transformation processes in landfills and offers practical insights for optimizing landfill management, reducing pollution, facilitating resource recovery and providing a theoretical model and prediction tool for sustainable waste management. Full article

Bacterial infections are a major complication in chronic obstructive pulmonary disease (COPD) and acute respiratory distress syndrome (ARDS), where mucus accumulation and pH fluctuations further hinder treatment. Nanostructured systems such as carbon dots (CDs) are increasingly investigated as antimicrobial agents due to their scalability, low cost, and biocompatibility, compared to conventional antibiotics. Here, CDs were synthesized by a one-step microwave-assisted method at three reaction temperatures (130 °C, 170 °C, and 185 °C, named LT-CDs, MT-CDs, HT-CDs, respectively) to explore the effect of carbonization on their structure and function. TEM, Raman, and FTIR analyses were employed to investigate the size and distribution of carbon groups. UV–vis confirmed distinct pH-dependent spectral responses, and mucoadhesion studies revealed stronger and more stable interactions for MT-CDs. Biological assays demonstrated high biocompatibility across all samples on lung fibroblasts, while antimicrobial tests highlighted a selective effect against Staphylococcus aureus, due to ROS generation. Overall, MT-CDs represented the best compromise in terms of size, functionalization, biocompatibility, mucoadhesion, and antimicrobial activity, emerging as promising nanoplatforms for respiratory infection management in COPD and ARDS. Full article

Lipases (EC 3.1.1.3) catalyze the hydrolysis of triacylglycerols into mono- and diacylglycerols and free fatty acids. This study investigated the production of lipase by Hypocrea pseudokoningii under solid-state fermentation (SSF), followed by its immobilization, purification, and biochemical characterization. Maximum activity was achieved using wheat fiber after 168 h of cultivation. Supplementation with oils enhanced production, particularly palm oil (315U; 1.58-fold increase) and soybean oil (Glycine max) (298U; 1.49-fold increase). The addition of micronutrients further improved yields, with Khanna (445U) and Vogel (400U) salts promoting more than a two-fold increase in activity. Immobilization on Octyl-Sepharose significantly altered the enzyme’s properties. The free lipase exhibited optimal activity at 45 °C and pH 4.5–5.5, while the immobilized enzyme showed maximum activity at 35–40 °C and pH 5.5. Thermal stability was notable enhanced: the free lipase had a half-life of 10 min at 50 °C, whereas the immobilized enzyme remained stable for 60 min and retained over 30% activity at 70 °C. Both the free and immobilized forms were stable across a broad pH range (4.0–10.0), maintaining more than 70% residual activity. The enzyme was stabilized by Tween 80 but inhibited by SDS. It was activated by Ca²⁺ and showed resistance to Pb²⁺, Zn²⁺, and Cu²⁺. Hydrolytic assays revealed murumuru (Astrocaryum murumuru), cupuaçu (Theobroma grandiflorum), and soybean oils as preferred substrates. TLC confirmed the formation of mono- and diglycerides, as well as the presence of fatty acids. Full article