Search Results (163)

The sustainable valorization of lignocellulosic biomass offers a promising route for developing low-cost photothermal materials for solar water purification. This study investigates natural fibers from Opuntia ficus-indica, Agave sisalana, and cellulose sponge, which were chemically purified through alkaline–peroxide pretreatment and subsequently functionalized with biochar via immersion and crosslinking-assisted deposition. Structural analyses (SEM, FTIR, XRD, CHNS/O) confirmed the transition from heterogeneous lignocellulosic matrices to cellulose-rich scaffolds and finally to hierarchical composites in which crystalline cellulose cores are coated with amorphous carbon structures containing aromatic domains typically formed during biomass carbonization. The NaOH/urea/citric acid crosslinking system significantly improved biochar adhesion, producing uniform and mechanically stable photothermal layers. Under 500 W m⁻² illumination, the biochar-modified fibers exhibited rapid thermal response and enhanced surface heating, resulting in increased water evaporation rates, with cellulose sponge achieving the highest performance (1.12–1.25 kg m⁻² h⁻¹). Water-quality analysis of the condensate showed >97% TDS removal, complete rejection of hardness, fluoride, nitrates, arsenic, and barium, and turbidity <0.2 NTU, meeting NOM-127-SSA1-2021 standards. Overall, the findings demonstrate that biochar-functionalized natural fibers constitute a scalable, environmentally benign strategy for efficient solar-driven purification, supporting their potential for sustainable clean-water technologies in resource-limited settings. Full article

To improve the efficiency of CO₂ hydrogenation, it is essential to develop new catalysts as well as new methods of producing them. In our work, we propose a new Fe-, Co-, Cu-containing catalyst preparation technique based on depositing the active component through urea hydrolysis using microwave heating. We also compare catalysts produced with microwave synthesis to samples obtained through traditional synthesis methods, including impregnation and thermal deposition. The obtained catalysts were characterized by XRD, low-temperature N₂ adsorption, SEM., and UV-VIS methods. The catalytic properties of the catalysts depend not only on the nature of the active component, but also on the preparation method. The best results for CO₂ hydrogenation were achieved with Ni-containing catalysts produced by the impregnation method and microwave synthesis. Full article

Background/Objectives: To explore the protective effects of 7-Ketolithocholic acid (7-KLCA) against renal fibrosis and its mechanism, focusing on its interaction with farnesoid X receptor (FXR). Methods: In vitro, TGF-β-induced fibrosis in HK-2/NRK-49F cells and LPS-induced inflammation in HK-2 cells were detected by CCK-8, Western blot, and qPCR. In vivo, unilateral ureteral obstruction (UUO) and adenine (Ade)-induced mouse models were treated with a low/high-dose 7-KLCA or losartan. Renal injury was evaluated via H&E/Masson staining, serum creatinine (SCR), and blood urea nitrogen (BUN) levels. The 7-KLCA-FXR interaction was verified by molecular docking, CETSA, and DARTS. FXR downstream genes and related proteins were measured by WB and qPCR. Results: 7-KLCA inhibited the expression of fibrotic proteins (fibronectin, collagen-I) and reduced the LPS-induced release of inflammatory factors (IL-1β, IL-6). In mice, it alleviated renal swelling, collagen deposition, and tubular damage, while lowering serum SCR and BUN levels. Mechanistically, 7-KLCA stably bound to the FXR ligand-binding domain, enhanced its thermal stability and degradation resistance. It upregulated FXR and its downstream genes SHP and FGF15, thereby inhibiting the activation of TGF-β/Smad and Wnt/β-catenin pathways. Conclusions: This is the first study to clarify the molecular mechanism through which 7-KLCA targets FXR and dually suppresses the key pro-fibrotic pathways TGF-β/Smad and Wnt/β-catenin, thereby exerting anti-renal fibrosis effects. Full article

Background and Objectives: Chemical androgen deprivation and estrogenization are essential components of clinical treatment for advanced prostate cancer and male-to-female sex transition. The aim of this study was to determine the effects of these therapies on anthropometric parameters, liver histology, and biochemical parameters, with the goal of establishing experimental models that accurately represent current clinical practice. Materials and Methods: Young adult Wistar rats were divided into nine groups: intact control (IC), control vehicle (CV), cyproterone acetate-treated (CA), flutamide-treated (F), control sesame oil (CO), estradiol valerate-treated (E), combined control (CC), flutamide + estradiol valerate (F + E), and cyproterone acetate + estradiol valerate (CA + E)-treated groups. Treatments were administered by subcutaneous injection for four weeks. Results: The administration of estradiol valerate, alone or combined with antiandrogens, reduced final body mass and white adipose tissue mass. Notable changes were observed in absolute and relative pituitary, liver, prostate, and testis mass in the E, F + E and CA + E groups. There were no significant changes in liver histology or glycogen deposition; however, the combined treatment groups showed an increased volume density of binucleated hepatocytes and fibrotic tissue. Regarding biochemical parameters, androgen deprivation and/or estrogenization caused marked changes in serum triglyceride, LDL (low-density lipoproteins), ALP (alkaline phosphatase), AST (aspartate aminotransferase), ALT (alanine aminotransferase), Bil-T (bilirubin), creatinine, and urea levels. Conclusions: Given the importance of these therapies in clinical practice, providing a model based on the evaluated parameters offers a solid platform for future research. Full article

Incorporating Cu into gold-based catalysts effectively reduced nanoparticle sintering and free carbonate accumulation, promoting long-term preservation of catalytic surface area over time. This study explores the catalytic activity of monometallic Au and bimetallic AuCu catalysts with varying Au:Cu atomic ratios (1:0.5, 1:1, and 1:1.5) that were synthesized on $\gamma$${\mathrm{-Al}}_2{\mathrm{O}}_3$ via sequential deposition–precipitation with urea. The catalysts were pretreated in either air or ${\mathrm{H}}_2$ and evaluated for CO oxidation activity and stability. A comprehensive characterization (EDS, BET, TEM, ${\mathrm{H}}_2$-TPR, ${\mathrm{O}}_2$-TPO, XPS, DRIFTS, and UV–Vis) was used to investigate particle size, metal oxidation states, and redox properties. Among all materials, the AuCu 1:1 catalyst exhibited the highest low-temperature CO conversion (>90% at 0 °C) and improved stability during 24 h tests, reflecting minimal nanoparticle sintering as confirmed by TEM analysis. In situ DRIFTS revealed that the presence of Cu⁺ and Cu²⁺ minimizes the accumulation of free carbonates (one of the main deactivation pathways in Au/$\gamma$${\mathrm{-Al}}_2{\mathrm{O}}_3$) while promoting the formation of reactive intermediates that facilitate ${\mathrm{CO}}_2$ production. Notably, air pretreatment at moderate temperature proved as effective as ${\mathrm{H}}_2$ pretreatment in activating both monometallic and bimetallic catalysts. These findings highlight the role of Cu as a structural and electronic promoter of gold, offering practical guidelines for designing durable, cost-effective catalysts for low-temperature CO oxidation on non-reducible supports. Full article

Porous Ni, Ni–Ir, and Ni–Pt electrodes were prepared on Ni substrates by molten-salt Al co-deposition followed by dealloying. SEM/EDS and XRD confirmed a Raney-type porous network with Ir or Pt present across the layer. A urea oxidation reaction (UOR) was tested in 1 M NaOH + 0.33 M urea by cyclic voltammetry and chronoamperometry at +0.40 V vs. SCE (60 min). Smooth Ni showed near-zero current. Porous Ni resulted in ~11 mA cm⁻² initially and ~9 mA cm⁻² after 60 min. Porous Ni–Ir started at ~7 mA cm⁻² and fell to ~2 mA cm⁻² within 5 min, indicating fast deactivation, likely due to Ir-oxide formation that suppresses the Ni²⁺/Ni³⁺ redox couple. Porous Ni–Pt remained at ~11 mA cm⁻² over 60 min, consistent with a stable Ni–Pt effect in which Pt aids urea adsorption/activation while Ni provides the redox path for oxidation. Overall, Pt improves UOR performance, whereas Ir lowers it under these conditions. Full article

Cracks in concrete dam tunnels compromise structural safety, watertightness, and durability, while conventional repair materials such as epoxy and cement impose environmental burdens. This study investigates biomineralization methods, namely Microbially Induced Calcium Carbonate Precipitation (MICP) and Enzyme-Induced Carbonate Precipitation (EICP), for repairing fine cracks in a large hydropower dam tunnel. Laboratory tests and field applications were conducted by injecting urea–calcium solutions with Sporosarcina pasteurii for MICP and soybean-derived urease for EICP, applied twice daily over three days. Both techniques achieved effective sealing, with precipitation efficiencies of 93.75% for MICP and 84.17% for EICP. XRD analysis revealed that MICP produced a mixture of vaterite and calcite, reflecting biologically influenced crystallization, whereas EICP yielded predominantly calcite, the thermodynamically stable phase. SEM confirmed that MICP generated irregular layered clusters shaped by microbial activity, while EICP formed smoother spherical and more uniform deposits under enzyme-driven conditions. The results demonstrate that MICP provides higher efficiency and localized nucleation control, while EICP offers faster kinetics and more uniform deposition. Both methods present eco-friendly and field-applicable alternatives to conventional repair, combining technical performance with environmental sustainability for hydraulic infrastructure maintenance. Full article

The prevalence of hyperuricemia with elevated serum uric acid is increasing worldwide. However, the effects of high uric acid on diabetic patients with dyslipidemia and the mechanisms underlying these effects remain unexplored. This study aimed to develop a novel diabetic model of hyperuricemia and dyslipidemia in male hamsters to evaluate the effects of high uric acid on glucolipid metabolism, renal injury and the gut microbiota. Twelve healthy hamsters were randomly divided into two groups and fed with a normal diet and high-fat/cholesterol diet (HFCD), respectively. Twenty-four diabetic hamsters were randomly divided into four groups receiving a normal diet; HFCD; potassium oxonate (PO) treatment (intragastric PO at doses of 350 mg/kg and adenine at doses of 150 mg/kg with 5% fructose water); and PO treatment with HFCD, respectively. After 4 weeks, all animals were dissected for determining serum biochemical indicators, tissue antioxidant parameters, renal pathological changes, target gene expressions, fecal short-chain fatty acids content, and the gut microbiota composition. The results showed that a hamster model with hyperuricemia and dyslipidemia was successively established by the combination of PO treatment and HFCD, in which serum uric acid, glucose, triglyceride and total cholesterol levels reached 499.5 ± 61.96 μmol/L, 16.88 ± 2.81 mmol/L, 119.88 ± 27.14 mmol/L and 72.92 ± 16.62 mmol/L, respectively. PO treatment and HFCD had synergistic effects on increasing uric acid, urea nitrogen, creatinine levels, liver xanthine oxidase activity, plasminogen activator inhibitor-1 and transforming growth factor-β expressions, and the relative abundance of Lleibacterium (p < 0.05); in addition, they caused glomerular mesangial cells and matrix proliferation, protein casts and urate deposition. High uric acid was closely related to decreased antioxidant capacity; decreased renal vascular endothelial growth factor expression; increased acetic acid content; decreased butyric, propanoic, and isobutyric acid levels; decreased Firmicutes to Bacteroidetes ratios (p < 0.05); and altered epithelial integrity and structure of the gut microbiota in diabetic hamsters. The findings indicate that high uric acid affects the glucolipid metabolism, accelerates renal damage, and disrupts the balance of intestinal flora in diabetic animals, which provides a scientific basis for metabolic syndrome prevention and control in diabetes. Full article

Combustion processes in compression ignition engines lead to the inevitable generation of nitrogen oxides, which cannot be limited to the currently desired levels just by optimising the in-cylinder processes. Therefore, simulation-based engine development needs to include all engine-related aspects which contribute to tailpipe emissions. Among them, the SCR (selective catalytic reduction) aftertreatment-related processes, such as urea–water solution injection, urea decomposition, mixing, NOx catalytic reduction, and deposits’ formation, are the most challenging, and require as much attention as the processes taking place inside the cylinder. Over the last decade, the urea-SCR aftertreatment systems have evolved from underfloor designs to close-coupled (to the engine) architecture, characterised by the short mixing length. Therefore, they need to be tailor-made for each application. This study presents the CFD-based development of a multi-platform SCR system with a short mixing length for mobile non-road applications, compliant with Stage V NRE-v/c-5 emission standard. It combines multiphase dispersed flow, including wall wetting and urea decomposition kinetic reaction modelling to account for the critical aspects of the SCR system operation. The baseline system’s design was characterised by the severe deposit formation near the mixer’s outlet, which was attributed to the intensive cooling in the mounting area. Moreover, as the simulations suggested, the spray was not appropriately mixed with the surrounding gas in its primary zone. The proposed measures to reduce the wall film formation needed to account for the multi-platform application (ranging from 56 to 130 kW) and large-scale production capability. The performed simulations led to the system design, providing excellent UWS–exhaust gas mixing without a solid deposit formation. The developed system was designed to be manufactured and implemented in large-scale series production. Full article

Electro-oxidation of urea (UOR) in alkaline medium is one of the most effective alternative ways of producing green hydrogen, as the oxidation potential in UOR is less and thermodynamically more favorable than conventional water oxidation. The development of cost-effective materials in catalyzing UOR is recently seeking more attention in the research hotspot. Suitably modifying the Ni-based catalysts towards active site creation and preventing surface passivation is much important in this context, following which we reported the synthesis of Ni₃S₂ (NS) supported with CuCo (CC) bimetallic (NSCC). A simple hydrothermal route for NS synthesis and the electrodeposition method for CuCo (CC) deposition is adapted in a self-supported manner. The NS and CC catalysts exhibited sheet-like morphology, as confirmed by SEM and TEM analysis. The bimetallic CC deposition prevented the surface passivation of nickel sulfide (NS) over oxygen evolution reaction (OER) and improved the charge-transfer kinetics. The NSCC catalyst catalyzed UOR in an alkaline medium, which required a lower potential of 1.335 V vs. RHE to attain the current density of 10 mAcm⁻², with a lower Tafel slope value of 131 mVdec⁻¹. In addition, a two-electrode cell setup is constructed with an operating cell voltage of 1.512 V for delivering 10 mAcm⁻² current density. This study illustrates the new strategy of designing heterostructure catalysts for electrocatalytic UOR. Full article

Acid deposition, a major environmental issue causing soil acidification and microbial suppression, impacts forest nutrient cycling. Meanwhile, nitrogen (N) fertilization is widely applied in subtropical forests, yet its interaction with acid deposition on litter decomposition is unclear. We conducted a field experiment using two common tree species, Cunninghamia lanceolata and Cinnamomum camphora, and applied three acid deposition levels (0, 0.25, and 0.50 g H⁺ m⁻² month⁻¹) and four N fertilization levels (0, 3, 6, and 9 g N m⁻² year⁻¹) in a factorial design. Our results showed that acid deposition alone significantly reduced litter decomposition rates, with maximum mass loss decreasing by 23.6% for Cunninghamia and 36.3% for Cinnamomum (p < 0.05). Urea fertilization alone also suppressed decomposition, reducing maximum mass loss by 27.3% for Cunninghamia and 37.3% for Cinnamomum (p < 0.05). However, when combined, urea fertilization mitigated the suppressive effect of acid deposition, particularly under severe acid conditions, where maximum mass loss increased by 18.5% for Cunninghamia and 43.1% for Cinnamomum (p < 0.05). Acid deposition reduced microbial respiration and enzyme activities related to carbon cycling, while urea fertilization showed both positive and negative effects depending on the acid levels (p < 0.05). Urea can enhance the litter layer’s acid-buffering capacity, offering potential management insights for acid deposition-affected forests. Further research on microbial mechanisms across ecosystems is recommended. Full article

The simultaneous generation of hydrogen fuel and wastewater remediation via electrocatalytic urea oxidation has emerged as a promising approach for sustainable energy and environmental solutions. However, the practical application of this process is hindered by the limited active sites and high charge-transfer resistance of conventional anode materials. In this work, we introduce a novel CoP@P, N-CNTs/NF electrocatalyst, fabricated through a facile one-step thermal annealing technique. Comprehensive characterizations confirm the successful integration of CoP nanoparticles and phosphorus/nitrogen co-doped carbon nanotubes (P, N-CNTs) onto nickel foam, yielding a unique hierarchical structure that offers abundant active sites and accelerated electron transport. As a result, the CoP@P, N-CNTs/NF electrode achieves outstanding urea oxidation reaction (UOR) performance, delivering current densities of 158.5 mA cm⁻² at 1.5 V and 232.95 mA cm⁻² at 1.6 V versus RHE, along with exceptional operational stability exceeding 50 h with negligible performance loss. This innovative, multi-element-doped electrode design marks a significant advancement in the field, enabling highly efficient UOR and energy-efficient hydrogen production. Our approach paves the way for scalable, cost-effective solutions that couple renewable energy generation with effective wastewater treatment. Full article

An electrochemical immunosensor for the quantification of prostate-specific antigens (PSAs) using silver nanocrystals (AgNCs) is reported. The silver nanocrystals were synthesized using a conventional citrate reduction protocol. The silver nanocrystals were characterized using scanning electron microscopy (SEM) and field effect scanning electron microscopy (FESEM), X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), Fourier-transform infrared spectroscopy (FTIR), UV-Vis spectroscopy, and small-angle X-ray scattering (SAXS). The proposed immunosensor was fabricated on a glassy carbon electrode (GCE), sequentially, by drop-coating AgNCs, the electro-deposition of EDC-NHS, the immobilization of anti-PSA antibody (Ab), and dropping of bovine serum albumin (BSA) to prevent non-specific binding sites. Each stage of the fabrication process was characterized by cyclic voltammetry (CV). Using square wave voltammetry (SWV), the proposed immunosensor displayed high sensitivity in detecting PSA over a concentration range of 1 to 10 ng/mL with a detection limit of 1.14 ng/mL and R² of 0.99%. The immunosensor was selective in the presence of interfering substances like glucose, urea, L-cysteine, and alpha-methylacyl-CoA racemase (AMACR) and it showed good stability and repeatability. These results compare favourably with some previously reported results on similar or related technologies for PSA detection. Full article

Cisplatin (Cis) is a widely used chemotherapy drug, but its nephrotoxicity limits its clinical application. Acute kidney injury (AKI) is a common complication, restricting long-term use. This study investigates the mechanisms of cisplatin-induced AKI and explores potential therapeutic targets. C57BL/6J mice were intraperitoneally injected with 20 mg/kg cisplatin to establish an AKI model. Serum creatinine, urea nitrogen, and tubular injury biomarkers (NGAL, KIM-1) progressively increased, indicating kidney dysfunction. Mitochondrial ATP levels significantly decreased, along with reduced mitochondrial fission and fusion, suggesting mitochondrial dysfunction. Increased oxidases and reduced antioxidants indicated redox imbalance, and metabolic reprogramming was observed, with lipid deposition, impaired fatty acid oxidation (FAO), and enhanced glycolysis in proximal tubular epithelial cells (PTECs). Nuclear factor erythroid 2-related factor 2 (NRF2) is a key transcriptional regulator of redox homeostasis and mitochondrial function. We found NRF2 levels increased early in AKI, followed by a decrease in vivo and in vitro, suggesting activation in the stress response. Nfe2l2 knockout mice showed aggravated kidney injury, characterized by worsened kidney function and histopathological damage. Mechanistically, Nfe2l2 knockout resulted in redox imbalance, reduced ATP synthesis, mitochondrial dysfunction and metabolic dysregulation. Furthermore, we activated NRF2 using dimethyl fumarate (DMF), observing a reduction in kidney damage and lipid deposition in mice. In conclusion, activating NRF2-dependent antioxidant pathways plays a crucial role in protecting against cisplatin-induced AKI. NRF2 may serve as a potential target for developing therapeutic strategies to prevent cisplatin nephrotoxicity. Full article

Transition metal-based catalysts designed for efficient urea oxidation reactions (UOR) are essential for hydrogen production via urea-assisted water electrolysis. A series of amorphous nickel–cobalt boride catalysts supported on nickel foam were in situ synthesized via a stepwise chemical deposition method (SCDM). The systematic investigation focused on the relationships between synthesis parameters (deposition cycles, reactant feed ratio), morphological characteristics, and UOR performance. Notably, the optimized Co-NiB@NF catalyst exhibits a porous hierarchical architecture composed of metallic nanoparticles encapsulated by surface-wrinkled nanosheets, forming abundant exposed active sites. Electrochemical measurements demonstrate that this catalyst requires a low cell potential of 1.29 V to achieve a current density of 10 mA cm⁻². Moreover, it maintains 83% of the initial current density after 10 h of continuous electrolysis, highlighting its superior durability. The structural-property relationship revealed here provides valuable insights into the rational design of efficient amorphous boride catalysts for urea-assisted hydrogen production. Full article