Search Results (9,972)

The cross-linking process of collagen is one of the more important ways to improve the mineralization ability of collagen. However, the regulatory effect of dynamic cross-linking on biomineralization in vitro remains unclear. Dynamic-cross-linked mineralized collagen under different cross-linking processes, according to the process of cross-linking and mineralization of natural bone, was prepared in this study. Mineralization was performed for 12 h at 4, 8, and 12 h of collagen cross-linking. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed the characteristics of dynamic-cross-linked mineralization in terms of morphological transformation and distribution. Fourier transform infrared spectroscopy (FTIR) analysis showed the crystallinity characteristics of the hydroxyapatite (HA) crystal formation. Pre-cross-linked dynamic-cross-linked mineralization refers to the process of cross-linking for a period of time and then side cross-linked mineralization. The mineral content, enzyme stability, and mechanical properties of mineralized collagen were improved through a dynamic cross-linking process of pre-cross-linking. The swelling performance was reduced through the dynamic cross-linking process of pre-cross-linking. This study suggests that the dynamic cross-linking process through pre-cross-linking could make it easier for minerals to permeate and deposit between collagen fibers, improve mineralization efficiency, and, thus, enhance the mechanical strength of biomineralization. This study can provide new ideas and a theoretical basis for designing mineralized collagen scaffolds with better bone repair ability. Full article

The increasing prevalence of multidrug-resistant (MDR) pathogens, persistent biofilms, oxidative stress, and cancerous cell proliferation poses significant challenges in healthcare and environmental settings, highlighting the urgent need for innovative and sustainable therapeutic solutions. The exploration of nanotechnology, particularly the use of green-synthesized nanoparticles, offers a promising avenue to address these complex biological challenges due to their multifunctional properties and biocompatibility. Utilizing a green synthesis approach, Mauritia flexuosa Mf-Ag₂ONPs were synthesized and characterized using dynamic light scattering (DLS), transmission electron microscopy (TEM), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy coupled with scanning electron microscopy (EDS-SEM), UV-Vis spectroscopy, and Fourier transform infrared spectroscopy (FTIR). The Mf-Ag₂ONPs exhibited potent antibacterial effects against both non-resistant and MDR bacterial strains, with minimum inhibitory concentrations (MICs) ranging from 11.25 to 45 µg/mL. Mf-Ag₂ONPs also demonstrated significant antifungal efficacy, particularly against Candida glabrata, with an MIC of 5.63 µg/mL. Moreover, the nanoparticles showed strong biofilm inhibition capabilities and substantial antioxidant properties, underscoring their potential to combat oxidative stress. Additionally, Mf-Ag₂ONPs exhibited pronounced anticancer properties against various cancer cell lines, displaying low IC₅₀ values across various cancer cell lines while maintaining minimal hemolytic activity at therapeutic concentrations. These findings suggest that Mf-Ag₂ONPs synthesized via an eco-friendly approach offer a promising alternative for biomedical applications, including antimicrobial, antifungal, antioxidant, and anticancer therapies, warranting further in vivo studies to fully exploit their therapeutic potential. Full article

The purpose of this research is to design nanocomposite materials for biomedical applications. New conjugates of PEG derivatives of RGD peptides and magnetic nanoparticles, based on Fe₃O₄ (MNPs) with silica coating covalently labelled with fluorescent dye Cyanine5, were obtained. It was shown that a higher loading level of RGD peptides occurred in the case of MNPs with SiO₂/aminopropylsilane coating, synthesised using N-(phosphonomethyl)iminodiacetic acid (PMIDA) as a surfactant. To confirm the structure and chemical purity of the new RGD-PEG conjugate, a number of methods were used, including ¹H NMR, HRMS, and RP-HPLC. The characterisation of MNPs was carried out using the following physical methods: TEM, FTIR, EDX, CHN analysis, DLS, fluorescence spectrometry, vibration magnetometry, and relaxometry. Samples obtained from PMIDA-stabilised MNPs contained a greater amount of the peptide and possessed better hydrodynamic characteristics than samples obtained from non-stabilised MNPs. A comparative study of the MNP cytotoxicity was carried out towards 4T1 and MDA-MB231 cell lines (MTT test), and the possibility of cell labelling was assessed. The cellular uptake was more efficient for nanoconjugates obtained without PMIDA. The data obtained can be used for the design of materials for cell labelling and visualisation. Full article

MDR bacteria are an emerging global threat to public health, and the role of dogs in the rise of antimicrobial resistance is under investigation. This study investigated the fecal shedding of extended-spectrum β-lactamase (ESBL)-, AmpC- and carbapenemase (CP)-producing Escherichia coli and associated risk factors in dogs admitted to the Veterinary Teaching Hospital of Lodi, University of Milan, or other veterinary clinics and kennels in Northen Italy. Feces collected in 2020–2022 were microbiologically and molecularly analyzed. ESBL-/AmpC-/CP-producing E. coli was detected in 14/100 (14%) dogs. Eleven (11%), five (5%) and one (1%) dogs carried ESBL-, AmpC- and CP-producing E. coli phenotypes, respectively, supported by the PCR detection of bla_CTX-M and/or bla_TEM in ESBL-producing E. coli; bla_CMY-2 and the presence of putative low-level AmpC production in AmpC-producing E. coli; and bla_OXA-48 in CP-producing E. coli. Different combinations of resistance genes and genetic features were observed. Multidrug resistance was observed in 13/14 (92.9%) E. coli isolates. Binary logistic regression analysis showed that ESBL-/AmpC-/CP-producing E. coli fecal shedding tended to be associated with antibiotic treatment (p = 0.058; OR = 3.87). The detection of ESBL-/AmpC-producing E. coli, along with the presence of a carbapenemase-resistant E. coli isolate from domestic dogs, although still limited, emphasizes the need for antimicrobial stewardship and specific surveillance programs, particularly for CP-producing bacteria in companion animals. Full article

This study explored the preparation of pure silica KIT-6, as well as KIT-6 materials with an enhanced concentration of surface OH groups through aluminum incorporation or NH₄F treatment. These materials with various contents of surface OH groups were subsequently modified via the post-synthesis grafting of sulfonic groups using 3-mercaptopropyltrimethoxysilane as a precursor, followed by oxidation to introduce acidic sites. The catalysts were thoroughly characterized using XRD, nitrogen adsorption/desorption, SEM-EDS, TEM, and FT-IR techniques to confirm their structural and chemical properties. The catalytic activity of acid-functionalized mesoporous silicas of the KIT-6 structure was further evaluated in the acetalization of glycerol to produce solketal. The results demonstrated a significant influence of the surface OH group concentration and acidic site density on catalytic performance, with KIT-6_F_SO₃H showing the highest efficiency in glycerol-to-solketal conversion. This study provides valuable insights into the design of efficient catalytic systems for the valorization of biodiesel-derived glycerol into high-value chemicals, offering a sustainable approach to waste glycerol utilization. Full article

Titanium nitride and vanadium nitride–carbon-based composite systems, TiN/C and VN/C, were prepared using a new synthesis method based on the thermal decomposition of titanyl tetraphenyl porphyrin (TiOTPP) and vanadyl tetraphenyl porphyrin (VOTPP), respectively. The structure of the TiN/C and VN/C composite materials, as well as their precursors, were characterized using Fourier Transformed Infrared Spectroscopy, X-Ray diffraction (XRD), X-Ray energy dispersive (EDS) and X-Ray photoelectron spectroscopy (XPS). Morphologies of the TiN/C and VN/C composites were examined by means of scanning electron (SEM) and transmission electron (TEM) microscopy. The synthesis of the non-metalated tetraphenyl porphyrin, the titanium, and vanadium tetraphenyl porphyrin complexes were confirmed using FTIR. The thermal decomposition of the titanium and vanadium tetraphenyl porphyrin complexes produced the respective metal nitride encapsulated in a carbon matrix; this was confirmed by XRD, SEM, TEM, and XPS. From the XRD patterns, it was determined that the TiN and VN were presented in cubic form with expected space group FM-3M and 1:1 (metal:N) stoichiometry. The XPS results confirmed the presence of both TiN and VN in the carbon matrix without metal carbides. The SEM and TEM results showed that both TiN and VN nanoparticles formed small clusters throughout the carbon matrix; the EDS results revealed a uniform composition. The synthesis method presented in this work is novel and serves as an effective means to produce TiN and VN NPs with good structure and morphology embedded in a carbon matrix. Full article

This study presents a comprehensive investigation into the synthesis, characterization, and photocatalytic performance of NiTiO₃/TiO₂ nanocomposites for solar hydrogen production. Through a carefully optimized sol–gel method, we synthesized a heterojunction photocatalyst comprising 99.2% NiTiO₃ and 0.8% anatase TiO₂. Extensive characterization using XRD, Raman spectroscopy, FTIR, UV–visible spectroscopy, photoluminescence spectroscopy, and TEM revealed the formation of an intimate heterojunction between rhombohedral NiTiO₃ and anatase TiO₂. The nanocomposite demonstrated remarkable improvements in optical and electronic properties, including enhanced UV–visible light absorption and an 85% reduction in charge carrier recombination compared to pristine NiTiO₃. Crystallite size analysis showed a reduction from 53.46 nm to 46.35 nm upon TiO₂ incorporation, leading to increased surface area and active sites. High-resolution TEM confirmed the formation of well-defined interfaces between NiTiO₃ and TiO₂, with lattice fringes of 0.349 nm and 0.249 nm corresponding to their respective crystallographic planes. Under UV irradiation, the NiTiO₃/TiO₂ nanocomposite exhibited superior photocatalytic performance, achieving a hydrogen evolution rate of 9.74 μmol min⁻¹, representing a 17.1% improvement over pristine NiTiO₃. This enhancement is attributed to the synergistic effects of improved light absorption, reduced charge recombination, and efficient charge separation at the heterojunction interface. Our findings demonstrate the potential of NiTiO₃/TiO₂ nanocomposites as efficient photocatalysts for solar hydrogen production and contribute to the development of advanced materials for renewable energy applications. Full article

Nanotechnological methods for creating multifunctional fabrics are attracting global interest. The incorporation of nanoparticles in the field of textiles enables the creation of multifunctional textiles exhibiting UV irradiation protection, antimicrobial properties, self-cleaning properties and photocatalytic. Nanomaterials-loaded textiles have many innovative applications in pharmaceuticals, sports, military the textile industry etc. This study details the biosynthesis and characterization of silver nanoparticles (AgNPs) using the aqueous mycelial-free filtrate of Aspergillus flavus. The formation of AgNPs was indicated by a brown color in the extracellular filtrate and confirmed by UV-Vis spectroscopy with a peak at 426 nm. The Box-Behnken design (BBD) is used to optimize the physicochemical parameters affecting AgNPs biosynthesis. The desirability function was employed to theoretically predict the optimal conditions for the biosynthesis of AgNPs, which were subsequently experimentally validated. Through the desirability function, the optimal conditions for the maximum predicted value for the biosynthesized AgNPs (235.72 µg/mL) have been identified as follows: incubation time (58.12 h), initial pH (7.99), AgNO₃ concentration (4.84 mM/mL), and temperature (34.84 °C). Under these conditions, the highest experimental value of AgNPs biosynthesis was 247.53 µg/mL. Model validation confirmed the great accuracy of the model predictions. Scanning electron microscopy (SEM) revealed spherical AgNPs measuring 8.93–19.11 nm, which was confirmed by transmission electron microscopy (TEM). Zeta potential analysis indicated a positive surface charge (+1.69 mV), implying good stability. X-ray diffraction (XRD) confirmed the crystalline nature, while energy-dispersive X-ray spectroscopy (EDX) verified elemental silver (49.61%). Scanning electron microscopy (SEM) revealed uniformly sized spherical AgNPs. Transmission electron microscopy (TEM) revealed spherical particles measuring 8.93–19.11 nm. EDX spectrum revealed that silver is the dominant element in the AgNPs. The Zeta potential measurement revealed a positive surface charge (+1.69 mV). X-ray diffraction (XRD) confirmed the crystalline character. FTIR findings indicate the presence of phenols, proteins, alkanes, alkenes, aliphatic and aromatic amines, and alkyl groups which play significant roles in the reduction, capping, and stabilization of AgNPs. Cotton fabrics embedded with AgNPs biosynthesized using the aqueous mycelial-free filtrate of Aspergillus flavus showed strong antimicrobial activity. The disc diffusion method revealed inhibition zones of 15, 12, and 17 mm against E. coli (Gram-negative), S. aureus (Gram-positive), and C. albicans (yeast), respectively. These fabrics have potential applications in protective clothing, packaging, and medical care. In silico modeling suggested that the predicted compound derived from AgNPs on cotton fabric could inhibit Penicillin-binding proteins (PBPs) and Lanosterol 14-alpha-demethylase (L-14α-DM), with binding energies of −4.7 and −5.2 Kcal/mol, respectively. Pharmacokinetic analysis and sensitizer prediction indicated that this compound merits further investigation. Full article

Developing new nanomaterials and performing functionalization to increase their photocatalytic capacity are essential in developing low-cost, eco-friendly, and multipurpose-capacity catalysts. In this research, SnO₂/Se-doped quantum dots (QDs) covered with glycerol (SnO₂/Se-GLY) were synthesized using microwave irradiation. Then, their cover was replaced with glutaraldehyde through a ligand exchange procedure (SnO₂/Se-GLUT). The XRD analyses confirmed a tetragonal rutile structure of SnO₂. The HR-TEM analysis confirmed the generation of QDs with a size around 8 nm, and the optical analysis evidenced low bandgap energies of 3.25 and 3.26 eV for the SnO₂/Se-GLY and SnO₂/Se-GLUT QDs, respectively. Zeta-sizer analysis showed that the hydrodynamic sizes for both nanoparticles were around 230 nm (50 mg/L), and the zeta potential confirmed that SnO₂/Se-GLUT QDs were more stable than SnO₂/Se-GLY QDs. The cover-modified QDs (SnO₂/Se-GLUT) showed a higher and faster adsorption capacity, followed by a slower photocatalytic process than the original QDs (SnO₂/Se-GLY). The QTOF-LC-MS analysis confirmed MB degradation through the identification of intermediates such as azure A, azure B, azure C, and phenothiazine. Adsorption isotherm analysis indicated Langmuir model compliance, supporting the high monolayer adsorption capacity and efficiency of these QDs as adsorbent/photocatalytic agents for organic pollutant removal. This dual capability for adsorption and photodegradation, along with the demonstrated reusability, highlights the potential of SnO₂/Se QDs in wastewater treatment and environmental remediation. Full article

Wormlike micelles (WLMs) with tunable viscoelastic characteristics have emerged as indispensable smart materials with a wide range of applications, which have garnered intense interest over the past few decades. However, quantitatively predicting the effect of various hydrotropes on the rheological behaviors of WLMs remains a challenge. In this article, micelles were formed in a mixture of 3-hexadecyloxy-2-hydroxypropyltrimethylammonium bromide (R₁₆HTAB) and aromatic hydrotropes (e.g., sodium benzoate, sodium cinnamate and their derivatives, respectively) in an aqueous solution. The phase behavior, viscoelasticity and thickening mechanism were systematically studied by macroscopic observation, rheological measurements, electrostatic potential analysis and cryogenic transmission electron microscopy (Cryo-TEM). Rheological measurements were used to probe the remarkable viscoelastic properties of micelles stemming from their lengthening and entanglement under the interaction between R₁₆HTAB and hydrotropes with structural variations. For an equimolar system of R₁₆HTAB and cosolute (40 mM), the relaxation time decreases in the following order: SpMB > SoHB > S4MS > SmMB > S5MS > SB > SmHB > SoMB > SpHB. These results allow us to predict the possible rules for the self-assembly of R₁₆HTAB and aromatic hydrotropes, which is conductive to directionally designing and synthesizing smart wormlike micelles. Full article

The chemical engineering community has shown significant interest in investigating methods to decompose hydrogen sulfide into hydrogen and sulfur. However, there is still a lack of detailed experimental data enabling us to choose the optimal catalyst, reaction, and regeneration conditions, as well as the overall process design. The purpose of this work is to synthesize a series of catalysts and compare their catalytic activity under the same conditions, chosen on the basis of a possible large-scale H₂S conversion process. To achieve this, the obtained catalysts were characterized by BET, XRD, SEM, TEM, and XPS before and after the reaction. Decomposition was conducted in a laboratory fixed-bed reactor at a temperature of 500 °C, 10 vol% of H₂S in the feed, and a GHSV of 540–1000 h⁻¹. DFT calculations evaluated the H₂S bond cleavage on various catalyst surfaces. It was shown that the most promising catalyst was Ni₃S₂, offering an acceptable H₂S conversion of 40%. We also observed that Ni₃S₂ catalyst regeneration could be conducted at much milder conditions compared to those previously reported in the literature. These results highlight the viability of upscaling the process with the selected catalyst. Full article

In this study, the synthesis of hybrid photocatalysts of Zn-Al-In mixed metal oxides were activated by using visible light, derived from Zn-Al-In layered double hydroxide (ZnAlIn-LDH), and these nanocomposites demonstrated high efficiency for photocatalytic H₂ production under UV light when using methanol as a sacrificial agent. The most active photocatalytic material produced 372 μmol h⁻¹ g⁻¹ of H₂. The characterization of these materials included X-ray diffraction (DRX), infrared spectroscopy (FTIR), X-ray fluorescence spectroscopy (XRF), X-ray spectroscopy (XEDS), scanning electron microscopy analysis (SEM), transmission electron microscopy (TEM), diffuse reflectance spectroscopy, and N₂- physisorption. In addition, the materials were characterized by photoelectrochemical techniques to explain the photocatalytic behavior. Subsequently, the photocatalytic performance for the water-splitting reactions under visible irradiation was evaluated. The ZnAlIn-MMOs with an In/(Al + In) molar ratio of 0.45 exhibited the highest photocatalytic activity in tests under visible light, attributed to the efficient separation and transport of photogenerated charge carriers originating from the new nanocomposite. This discovery indicates a method for developing new types of heteronanostructured photocatalysts which are activated by visible light. Full article

The irregular and deep cracks induced by thermal shock in Al₂O₃ ceramics were repaired by applying Cu powder layer on their surface and heating at 1200 °C under an atmosphere of air. The Al-Cu-O liquid phase formed at 1200 °C by the reaction of molten Cu, oxygen, and Al₂O₃ phases penetrate deep into the narrow cracks, and the precipitation phases of Cu₂O and CuAlO₂ densely fill the crack interior. Our observation and analysis of the filled cracks and the surrounding areas of the repaired cracks, as well as the microstructural analysis results obtained through SEM-EDS and TEM observation, suggested the aforementioned crack repair mechanism. The bending strength of the coated surface after repairing the cracks is 301.8 MPa (ΔT = 300 °C), which is twice as strong as the specimen after thermal shock and 10% higher than the original strength of the base material. Full article

The strengthening mechanism of Nb, V, and Nb-V micro-alloyed high-strength bolt steels was investigated and compared using microstructural evolution and strength modeling. Optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD) were used to characterize the microstructure and precipitations. The results show that Nb-V composite micro-alloyed steel possessed a higher yield strength compared with Nb or V micro-alloyed steel when quenched at 870 °C and tempered at 450–650 °C. Furthermore, the strength increment of Nb-V micro-alloyed steel with respect to Nb or V micro-alloyed steel reached the maximum at a tempering temperature of 600 °C, and precipitation strengthening and dislocation strengthening presented higher strength contributions in Nb-V micro-alloyed steel than in Nb micro-alloyed steel and V micro-alloyed steel owing to the higher volume fraction and finer precipitate size. When V was added in combination with Nb in steel, the number of Nb-rich carbonitrides increased, which resulted in a higher volume fraction of the effective pinning particles-Nb-rich (Ti,Nb,V)(C,N) with diameters smaller than 50 nm and led to an enhanced refinement of the prior austenite grain. In addition, Nb could reduce the consumption of V during quenching, allowing more V to be solid-solved in the matrix after quenching, thereby further enhancing the precipitation strengthening effect of V during tempering. Full article

Nanoparticles derived from biological sources are currently garnering significant interest due to their diverse range of potential applications. The purpose of the study was to synthesize Al-doped nanoparticles of zinc oxide (ZnO) from leaf extracts of Cucumis maderaspatanus and assess their antioxidant and antimicrobial activity using some bacterial and fungal strains. These nanoparticles were analyzed using X-ray diffraction (XRD), ultraviolet–visible (UV-vis) spectroscopy, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDAX), transmission electron microscopy (TEM), and thermogravimetric analysis/differential thermal analysis (TG-DTA). The average crystalline size was determined to be 25 nm, as evidenced by the XRD analysis. In the UV-vis spectrum, the absorption band was observed around 351 nm. It was discovered that the Al-ZnO nanoparticles had a bandgap of 3.25 eV using the Tauc relation. Furthermore, by FTIR measurement, the presence of the OH group, C=C bending of the alkene group, and C=O stretching was confirmed. The SEM analysis revealed that the nanoparticles were distributed uniformly throughout the sample. The EDAX spectrum clearly confirmed the presence of Zn, Al, and O elements in the Al-ZnO nanoparticles. The TEM results also indicated that the green synthesized Al-ZnO nanoparticles displayed hexagonal shapes with an average size of 25 nm. The doping of aluminum may enhance the thermal stability of the ZnO by altering the crystal structure or phase composition. The observed changes in TG, DTA, and DTG curves reflect the impact of aluminum doping on the structural and thermal properties of ZnO nanoparticles. The antibacterial activity of the Al-ZnO nanoparticles using the agar diffusion method showed that the maximum zone of inhibition has been noticed against organisms of Gram-positive S. aureus compared with Gram-negative E. coli. Moreover, antifungal activity using the agar cup method showed that the maximum zone of inhibition was observed on Aspergilus flavus, followed by Candida albicans. Al-doping nanoparticles increases the number of charge carriers, which can enhance the generation of reactive oxygen species (ROS) under UV light exposure. These ROS are known to possess strong antimicrobial properties. Al-doping can improve the crystallinity of ZnO, resulting in a larger surface area that facilitates more interaction with microbial cells. The structural and biological characteristics of Al-ZnO nanoparticles might be responsible for the enhanced antibacterial activity exhibited in the antibacterial studies. Al-ZnO nanoparticles with Cucumis maderaspatanus leaf extract produced via the green synthesis methods have remarkable antioxidant activity by scavenging free radicals against DPPH radicals, according to these results. Full article