Search Results (2,440)

Ti-Mo-N coatings were deposited on GCr15 bearing steel using arc ion plating. The effect of deposition bias on the coating microstructure, mechanical properties, tribological behavior, and electrochemical corrosion resistance was systematically investigated. The coating prepared at −120 V bias showed optimal overall performance. It achieved the lowest friction coefficient (0.308) and lowest wear rate (1.99 × 10⁻⁶ mm³/N·m). The significant improvement in tribological performance is attributed to the lubricating phase formed during the friction process. XPS analysis confirmed the layered MoO₃ formation within the wear scar. Deposition bias also significantly influenced the coating texture. At −120 V, the coating exhibited the strongest (111) crystal plane preferred orientation. This texture strongly correlated with performance enhancement. Regarding electrochemical corrosion, the −120 V coating displayed the lowest corrosion current density (3.62 × 10⁻⁹ A/cm²) and best corrosion resistance. Its corrosion morphology showed no obvious pitting, grooves, or other damage features. The results demonstrate the critical role of deposition bias in tailoring Ti-Mo-N coating properties. This research provides essential experimental support and a theoretical basis for designing wear- and corrosion-resistant protective coatings on bearing steel. Full article

Aryl diazonium salt chemistry offers a robust and versatile approach for the modification of material surfaces via the covalent immobilization of reactive functional groups under mild conditions. In this study, this strategy was successfully applied to graft the chelating agent 4-(2-pyridylazo)resorcinol (PAR) onto Amberlite XAD-4 resin. Initially, 4-nitrobenzenediazonium tetrafluoroborate (NBDT) was covalently anchored onto the resin surface using hypophosphorous acid as a reducing catalyst to introduce aryl nitro groups. These nitro groups were subsequently reduced to aniline functionalities, enabling diazo coupling with PAR. The successful modification of the resin was confirmed by ATR-FTIR spectroscopy, thermogravimetric analysis (TGA), and X-ray photoelectron spectroscopy (XPS). The synthesized chelating resin exhibited sorption capacities of 0.152, 0.167, and 0.172 mM g⁻¹ for Co(II), Ni(II), and Cu(II), respectively. The functionalized resin was packed into standard SPE cartridges and employed as a selective sorbent for the extraction and preconcentration of trace metals from groundwater samples collected in Dhalamah Valley, Al-Madinah Al-Munawwarah, prior to quantification by inductively coupled plasma mass spectrometry (ICP-MS). These results demonstrate the effectiveness of rapid diazonium-based surface functionalization for the preparation of selective polymeric metal chelators suitable for the extraction of trace metals from complex groundwater matrices. Full article

This study investigated the influence of Cr, Mo, and W alloying elements incorporated into ferritic stainless steel on the characteristics of passive films formed under acidic chloride conditions. Electrochemical assessments demonstrated that increasing the amounts of Cr, Mo, and W reduces passive current density and enhances polarization resistance. Through XPS analysis, it was determined that the passive film exhibits a double-layer structure, consisting of an inner layer rich in metal oxides and an outer layer containing metal oxy-anions. Mott–Schottky analysis indicated the presence of both p-type and n-type semiconducting properties. To clarify the effect of these alloying elements on the passive films at the surface of stainless steel, this work introduces a new parameter termed the “Bipolar Index,” defined as |p-type slope| + |n-type slope|. With higher Cr, Mo, and W contents, the bipolar index increases, reflecting modifications in the semiconductive behavior. Consequently, the point defect concentration within the passive film decreases, causing a reduction in passive current density and a rise in polarization resistance. Full article

Plasma Electrolytic Polishing (PEP) is an advanced anodic process that enhances stainless steel surfaces through controlled electrochemical dissolution and plasma-mediated modification. This study demonstrates that PEP treatment of AISI 304 SS at 300 V in aqueous urea solution (3.0 wt.%)/NH₄NO₃ (0.25 wt.%) achieves remarkable improvements: surface roughness decreases by 54.6% (from 0.197 ± 0.023 μm to 0.0895 ± 0.0205 μm) with minimal mass loss (0.0035 g·cm⁻²) in just 20 min. Tafel analysis showed a 99% reduction in corrosion rate (0.00497 mm yr⁻¹) compared to untreated AISI 304 SS (0.094 mm yr⁻¹). Cyclic Potentiodynamic Polarization (CPDP) measurements indicated superior pitting resistance (E_pit = +0.423 vs. +0.486 V for PEP processing). XPS analysis elucidates the underlying mechanisms, showing a 91% increase in the Cr/Fe ratio (0.44 to 0.84) and complete transformation of surface oxides to protective Cr₂O₃ (57.34 wt.%) and Fe₃O₄ (55.88 wt.%), which collectively explain the enhanced corrosion resistance. Full article

Porous carbon-loaded MnO was prepared via a combination of the sol–gel method and the chemical blow molding method using polyvinylpyrrolidone (PVP) and manganese nitrate as starting materials. SEM, EDX, TEM, FTIR, XRD, XPS, nitrogen adsorption–desorption, and elemental analysis were used to assess its physical and chemical characteristics. Furthermore, the adsorption property of porous carbon-loaded MnO for hexavalent chromium (Cr(VI)) in polluted water was investigated in detail. The results demonstrated that large numbers of MnO nanoparticles were evenly mounted on the surfaces of carbon walls, with a uniform distribution of C, N, and O elements. The BET surface area was 46.728 m²/g, and the pore sizes of porous carbon ranged from 2 nm to 10 nm. Additionally, abundant surface functional groups were found in porous carbon-loaded MnO, a result consistent with XPS data and applicable to the adsorption of heavy metals from aqueous solutions containing Cr(VI). The Freundlich model fitted the adsorption isotherm well, and the pseudo−second−order model precisely matched the adsorption kinetics. According to the study results, the adsorption was multilayer, and the adsorption process involved an endothermic reaction. These results indicate that this is a feasible way to synthesize a high−efficiency adsorbent for the removal of harmful heavy−metal ions from wastewater. Full article

Speed is not only the primary objective of racehorse breeding but also a crucial indicator for evaluating racehorse performance. This study investigates a newly developed racehorse breed in China. Through whole-genome resequencing, we selected 60 offspring obtained from the crossbreeding of Thoroughbred horses and Xilingol horses for this study. This breed is tentatively named “Grassland-Thoroughbred”, and the samples were divided into two groups based on racing ability: 30 racehorses and 30 non-racehorses. Based on whole-genome sequencing data, the study achieved an average sequencing depth of 25.63×. The analysis revealed strong selection pressure on chromosomes (Chr) 1 and 3. Selection signals were detected using methods such as the nucleotide diversity ratio (π ratio), integrated haplotype score (iHS), fixation index (Fst), and cross-population extended haplotype homozygosity (XP-EHH). Regions ranked in the top 5% by at least three methods were designated as candidate regions. This approach detected 215 candidate genes. Additionally, the Fst method was employed to detect Indels, and the top 1% regions detected were considered candidate regions, covering 661 candidate genes. Functional enrichment analysis of the candidate genes suggests that pathways related to immune regulation, neural signal transmission, muscle contraction, and energy metabolism may significantly influence differences in performance. Among these identified genes, PPARGC1A, FOXO1, SGCD, FOXP2, PRKG1, SLC25A15, CKMT2, and TRAP1 play crucial roles in muscle function, metabolism, sensory perception, and neurobiology, indicating their key significance in shaping racehorse phenotypes. This study not only enhances understanding of the molecular mechanisms underlying racehorse speed but also provides essential theoretical and practical references for the molecular breeding of Grassland-Thoroughbreds. Full article

This study introduces an efficient and sustainable catalytic system utilizing cobalt ferrite nanoparticles (CoFe₂O₄-NPs) for the synthesis of valuable 6-amino-2-oxo-4-phenyl (or 4-chlorophenyl)-1,2,3,4-tetrahydropyrimidine-5-carbonitrile derivatives. Recognizing the limitations of traditional methods for the Biginelli reaction, we thoroughly characterized CoFe₂O₄-NPs, alongside individual iron oxide nanoparticles (Fe₂O₃-NPs) and cobalt oxide nanoparticles (CoO-NPs), using FTIR, XRD, TEM, SEM, XPS, TGA, and BET analysis. These characterizations revealed the unique structural, morphological, and physicochemical properties of CoFe₂O₄-NPs, including an optimized porous structure and significant bimetallic synergy between Fe and Co ions. Catalytic studies demonstrated that CoFe₂O₄-NPs significantly outperformed individual Fe₂O₃-NPs and CoO-NPs under mild conditions. While the latter only catalyzed the Knoevenagel condensation, CoFe₂O₄-NPs uniquely facilitated the complete Biginelli reaction. This superior performance is attributed to the synergistic electronic environment within CoFe₂O₄-NPs, which enhances reactant activation, intermediate stabilization, and proton transfer during the multi-step reaction. This work highlights the potential of CoFe₂O₄-NPs as highly efficient and selective nanocatalysts for synthesizing biologically relevant 1,2,3,4-tetrahydropyrimidines, offering a greener synthetic route in organic chemistry. Full article

Pressure therapy combined with silicone has a significant effect on scar hyperplasia, but limitations such as long-term wearing of compression garments (CGs) can easily cause bacterial infection, cleanliness, and lifespan problems of CGs caused by the tedious operation of applying silicone. In this study, a compression garment fabric (CGF) with both inhibition of scar hyperplasia and antibacterial function was prepared. A polydimethylsiloxane (PDMS)-loaded microcapsule (PDMS-M) was prepared with chitosan quaternary ammonium salt (HACC) and sodium alginate (SA) as wall materials and PDMS as core materials by the complex coagulation method. The PDMS-Ms were finished on CGF and modified with (3-aminopropyl)triethoxysilane (APTES) to obtain PDMS-M CGF, which was further treated with HACC to produce PDMS-M-HACC CGF. X-ray Photoelectron Spectroscopy(XPS) and Fourier transform infrared spectroscopy (FTIR) analysis confirmed the formation of covalent bonding between PDMS-M and CGF. The PDMS-M CGF exhibited antibacterial rates of 94.2% against Gram-negative bacteria Escherichia coli (E. coli, AATCC 6538) and of 83.1% against Gram-positive bacteria Staphylococcus aureus (S. aureus, AATCC 25922). The antibacterial rate of PDMS-M-HACC CGF against both E. coli and S. aureus reached 99.9%, with wash durability reaching grade AA for E. coli and approaching grade A for S. aureus. The finished CGF maintained good biocompatibility and showed minimal reduction in moisture permeability compared to unfinished CGF, though with decreased elastic recovery, air permeability and softness. The finished CGF of this study is expected to improve the therapeutic effect of hypertrophic scars and improve the quality of life of patients with hypertrophic scars. Full article

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

The hybrid inorganic–organic material concept plays a bold role in multifunctional materials, combining different features on one platform. Once varying properties coexist without cancelling each other on one matrix, a new type of supermaterial can be formed. This concept showed that silver nanoparticles can be embedded together with inorganic and organic surface coatings and silicon quantum dots for symbiotic antibacterial character and UV-excited visible light fluorescent features. Additionally, fluorosilane material can be coupled with this prepolymeric structure to add the hydrophobic feature, showing water contact angles around 120°, providing self-cleaning features. Optical properties of the components and the final material were investigated by UV-Vis spectroscopy and PL analysis. Atomic investigations and structural variations were detected by XPS, SEM, and EDX atomic mapping methods, correcting the atomic entities inside the coating. FT-IR tracked surface features, and statistical analysis of the quantum dots and nanoparticles was conducted. Multifunctional final materials showed antibacterial properties against E. coli and S. aureus, exhibiting self-cleaning features with high surface contact angles and visible light fluorescence due to the silicon quantum dot incorporation into the sol-gel-produced nanocomposite hybrid structure. Full article

A facile and versatile strategy to obtain NPs@ZnAlO nanocomposite materials, comprising controlled-size nanoparticles (NPs) within a ZnAlO matrix is reported. The mono-(Au, Ni) and bimetallic (Ni-Au) NPs serving as an active phase were prepared by the polyol-alkaline method, while the ZnAlO support was obtained via the thermal decomposition of its corresponding layered double hydroxide (LDH) precursors. X-ray diffraction (XRD) patterns confirmed the successful fabrication of the nanocomposites, including the synthesis of the metallic NPs, the formation of LDH-like structure, and the subsequent transformation to ZnO phase upon LDH calcination. The obtained nanostructures confirmed the nanoplate-like morphology inherited from the original LDH precursors, which tended to aggregate after the addition of gold NPs. According to the UV-Vis spectroscopy, loading NPs onto the ZnAlO support enhanced the light absorption and reduced the band gap energy. ATR-DRIFT spectroscopy, H₂-TPR measurements, and XPS analysis provided information about the functional groups, surface composition, and reducibility of the materials. The catalytic performance of the developed nanostructures was evaluated by the photodegradation of bisphenol A (BPA), under simulated solar irradiation. The conversion of BPA over the bimetallic Ni-Au@ZnAlO reached up to 95% after 180 min of irradiation, exceeding the monometallic Ni@ZnAlO and Au@ZnAlO catalysts. Its enhanced activity was correlated with good dispersion of the bimetals, narrower band gap, and efficient charge carrier separation of the photo-induced e⁻/h⁺ pairs. Full article

This study presents the development of Cu-doped NiMo/TiO₂ photoelectrocatalysts for simultaneous green hydrogen production and pharmaceutical pollutant removal under simulated solar irradiation. The catalysts were synthesized via wet impregnation (15 wt.% total metal loading with 0.6 wt.% Cu) and thermally treated at 400 °C and 900 °C to investigate structural transformations and catalytic performance. Comprehensive characterization (XRD, BET, SEM, XPS) revealed phase transitions, enhanced crystallinity, and redistribution of redox states upon Cu incorporation, particularly the formation of NiTiO₃ and an increase in oxygen vacancies. Crystallite sizes for anatase, rutile, and brookite ranged from 21 to 47 nm at NiMoCu400, while NiMoCu900 exhibited only the rutile phase with 55 nm crystallites. BET analysis showed a surface area of 44.4 m²·g⁻¹ for NiMoCu400, and electrochemical measurements confirmed its higher electrochemically active surface area (ECSA, 2.4 cm²), indicating enhanced surface accessibility. In contrast, NiMoCu900 exhibited a much lower BET surface area (1.4 m²·g⁻¹) and ECSA (1.4 cm²), consistent with its inferior photoelectrocatalytic performance. Compared to previously reported binary NiMo/TiO₂ systems, the ternary NiMoCu/TiO₂ catalysts demonstrated significantly improved hydrogen production activity and more efficient photoelectrochemical degradation of paracetamol. Specifically, NiMoCu400 showed an anodic peak current of 0.24 mA·cm⁻² for paracetamol oxidation, representing a 60% increase over NiMo400 and a cathodic current of −0.46 mA·cm⁻² at −0.1 V vs. RHE under illumination, nearly six times higher than the undoped counterpart (–0.08 mA·cm⁻²). Mott–Schottky analysis further revealed that NiMoCu400 retained n-type behavior, while NiMoCu900 exhibited an unusual inversion to p-type, likely due to Cu migration and rutile-phase-induced realignment of donor states. Despite its higher photosensitivity, NiMoCu900 showed negligible photocurrent, confirming that structural preservation and surface redox activity are critical for photoelectrochemical performance. This work provides mechanistic insight into Cu-mediated photoelectrocatalysis and identifies NiMoCu/TiO₂ as a promising bifunctional platform for integrated solar-driven water treatment and sustainable hydrogen production. Full article

Steel pickling sludge serves as a valuable iron source for synthesizing Fe-based catalysts in heterogeneous advanced oxidation processes (AOPs). Here, MoS₂@CoFe₂O₄ catalyst derived from steel pickling sludge was prepared via a facile solvothermal approach and utilized to activate peroxymonosulfate (PMS) for tetracycline hydrochloride (TCH) degradation. Comprehensive characterization using scanning electron microscopy (SEM)-energy dispersive spectrometer (EDS), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) confirmed the supported microstructure, composition, and crystalline structure of the catalyst. Key operational parameters—including catalyst dosage, PMS concentration, and initial solution pH—were systematically optimized, achieving 81% degradation efficiency within 30 min. Quenching experiments and electron paramagnetic resonance (EPR) analysis revealed SO₄^∙− as the primary oxidative species, while the catalyst maintained high stability and reusability across cycles. TCH degradation primarily occurs through hydroxylation, decarbonylation, ring-opening, and oxidation reactions. This study presents a cost-effective strategy for transforming steel pickling sludge into a high-performance Fe-based catalyst, demonstrating its potential for practical AOP applications. Full article

Benzoxazine resins are gaining attention for their impressive thermal stability, low water uptake, and strong mechanical properties. In this work, two new bio-based benzoxazine monomers were developed using renewable arbutin: one combined with 3-(2-aminoethylamino) propyltrimethoxysilane (AB), and the other with furfurylamine (AF). Both were synthesized using a simple Mannich-type reaction and verified through FT-IR and ¹H-NMR spectroscopy. By blending these monomers in different ratios, copolymers with adjustable thermal, dielectric, and surface characteristics were produced. Thermal analysis showed that the materials had broad processing windows and cured effectively, while thermogravimetric testing confirmed excellent heat resistance—especially in AF-rich blends, which left behind more char. The structural changes obtained during curing process were monitored using FT-IR, and XPS verified the presence of key elements like carbon, oxygen, nitrogen, and silicon. SEM imaging revealed that AB-based materials had smoother surfaces, while AF-based ones were rougher; the copolymers fell in between. Dielectric testing showed that increasing AF content raised both permittivity and loss, and contact angle measurements confirmed that surfaces ranged from water-repellent (AB) to water-attracting (AF). Overall, these biopolymers (AB/AF copolymers) synthesized from arbutin combine environmental sustainability with customizability, making them strong candidates for use in electronics, protective coatings, and flame-resistant composite materials. Full article

AAA+ ATPases are ring-shaped hexameric protein complexes that operate as elaborate macromolecular motors, driving a variety of ATP-dependent cellular processes. AAA+ ATPases undergo large-scale conformational changes that lead to the conversion of chemical energy from ATP into mechanical work to perform a wide range of functions, such as unfolding and translocation of the protein substrate inside a proteolysis chamber of an AAA+-associated protease. Despite extensive biochemical studies on these macromolecular assemblies, the mechanism of substrate unfolding and degradation has long remained elusive. Indeed, until recently, structural characterization of AAA+ protease complexes remained hampered by the size and complexity of the machinery, harboring multiple protein subunits acting together to process proteins to be degraded. Additionally, the major structural rearrangements involved in the mechanism of this complex represent a crucial challenge for structural biology. Here, we report the main advances in deciphering molecular details of the proteolytic reaction performed by AAA+ proteases, based on the remarkable progress in structural biology techniques. Particular emphasis is placed on the latest findings from high-resolution structural analysis of the ClpXP proteolytic complex, using crystallographic and cryo-EM investigations. In addition, this review presents some additional dynamic information obtained using solution-state NMR. This information provides molecular details that help to explain the protein degradation process by such molecular machines. Full article