Objective(s): Despite a global increase in dental implant procedures -now exceeding one million annually-there remains significant potential for advancement in implant materials. In order to create a better substitute for the materials used in dental implants today, this study examines how reinforcement with silicon dioxide (SiO₂) nanoparticles can improve the mechanical and physical properties of polyetherketoneketone (PEKK).Methods: Biomedical composites were prepared by incorporating SiO₂ nanoparticles into a PEKK matrix at weight percentages of 0%, 2%, 3%, and 4% (n=5 per group). The nanoparticle and polymer powders were homogenized in ethanol, dried at 120°C, and compression-molded at 310°C under 15 MPa for 20 minutes. The resulting specimens were evaluated for their mechanical (flexural strength), physical (surface roughness, wettability), and morphological (SEM, AFM) properties.Results: The incorporation of SiO₂ nanoparticles, particularly at 3 wt%, led to significant improvements in both mechanical and physical characteristics of the PEKK composite. The 3% SiO₂/PEKK group demonstrated the maximum flexural strength and improved surface hydrophilicity and roughness, which was verified with the help of SEM and AFM analysis.Conclusions: The results indicate that PEKK/3%SiO₂ nanocomposites possess enhanced biomechanical and biological behavior over the neat PEKK. The PEKK/3%SiO₂ nanocomposites hold the potential to be used as biocompatible substitutes of titanium in the field of dental implants.

Effect of SiO2 nanoparticles on rangeland plant of Bromus kopetdaghensis Drobov organs is accomplished through factorial test in a completely randomized design with four replications at Ferdowsi University of Mashhad, in 2014. Treatments included two levels of application (spray and impregnated with seeds), 5 concentrations level of SiO2 nanoparticles (1, 2, 10, 50, and 80 mg/l), and control (no SiO2 nanoparticles). Results showed that increase in concentration of nanoparticles, the plant organs such as height and weight parameters were decreased. However, SiO2 nanoparticles at low concentrations at the application of SiO2 nanoparticles method impregnated with the seed at a concentration of 10 mg/l and spraying nanoparticles at a concentration of 2 mg/l were increased plant height and weight, compared to treatment the control. Application of SiO2 nanoparticles are coated with seed treatments with a concentration of 10 mg/l was shown 24, 66 and 34 percent incensement, respectively for shoot dry weight, root dry weight and height compared to the control treatment. Application of spraying nanoparticles treated with 2 mg was shown 27, 68 and 35 percent incensement respectively for shoot dry weight, root dry weight and height compared to the control treatment. According to Bromus kopetdaghensis D. yield, it is suggested the method of SiO2 nanoparticles application impregnated with seed at a concentration of 10 mg/l due to lower consumption of nanoparticles, ease of nanoparticles use and being economical at natural lands.

Research subject: The presence of heavy metal ions in surface and underground water, followed by their infiltration into drinking water at high concentrations, poses irreparable risks to human health and the environment. In this context, solid-phase extraction (SPE) has recently been recognized as a routine and practical method for removing heavy metals from water and wastewater samples. Consequently, the development of selective adsorbents for application in the SPE method is of significant importance in environmental studies. Research Approach: In the present study, polyvinyl alcohol (PVA) molecules were functionalized onto Fe₃O₄@SiO₂ core-shell nanoparticles using cyanuric chloride and triethoxysilyl propylamine compounds. The synthesized nanoparticles were then employed as an effective adsorbent for the removal of Pb²⁺ ions from aqueous solutions. The structural characteristics, morphology, and particle size were analyzed using Fourier-transform infrared (FTIR) spectroscopy, energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), thermogravimetric analysis (TGA), vibrating sample magnetometry (VSM), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). Furthermore, the key operational parameters affecting adsorption performance were evaluated to optimize the adsorption capacity for the effective removal of heavy metal contaminants. Main Results: The optimal adsorption capacity of 89% was achieved under the following conditions: pH 7, a contact time of 35 minutes, 32 mg of adsorbent in 50 mL of solution with an initial Pb²⁺ concentration of 72.52 mg/L (0.35 mmol/L), at ambient temperature. Additionally, the synthesized nanoadsorbent demonstrated recyclability for up to five adsorption-desorption cycles without a significant decline in functional efficiency.

Various magnetite heterogeneous catalysts for the organic reaction are increasingly recognized while their stability still is a critical challenge. In this regard, SiO2, ionic liquid (IL), and polyvinyl pyrrolidone (PVP) were applied as a three-layer stabilization system for modifying magnetic Fe3O4 to produce Fe3O4@SiO2@IL‐, PVP as a novel nanocatalyst. The Fe3O4@SiO2@IL‐, PVP as stabilized heterogeneous catalysts were utilized in a robust, and environmentally friendly strategy for the preparation of the spirooxindole derivatives by the one-pot condensation of isatin, malononitrile, and 1, 3-dicarbonyl in a water solvent. The proposed method revealed a high yield spirooxindole derivatives preparation (99%) at short reaction times (1. 0 min), low catalyst mass (0. 002 g), and satisfactory temperature (30 °, C) which confirm the lack of any tedious challenge and promising applicability and reusability. This work introduces a rational core-shell nanosystem design with a facile and novel construction strategy to arrive at nonexquisite metal-based composite catalysts with superior catalytic proficiency and prominent long-term stability.

In this paper, pure and Cr-doped SiO2 was prepared by sol-gel method and deposited on glass substrates by dip-coating and calcination of the resulting thin films at 500 °C. An X-ray diffraction examination was performed for the pure and doped films, where we note the appearance of a spectrum in the form of a wide band at the equivalent Bragg angle at 2θ = 22.6°, which indicates that the obtained material is amorphous silica. After that, field emission scanning electron microscopy was conducted to study the morphology of the pure SiO2 thin layer doped with chromium, as it appears that the prepared film is of good quality and free of cracks and holes, as we note that the crystals adopted certain geometric shapes with different sizes and shapes. Likewise, the particle distribution is uniform with the spherical shape. By examining the atomic force microscope to study the surface topography and roughness, we notice that the surface roughness increases with the increase in the doping percentage, where the surface roughness values ​​of the samples vary between (2.94-5.22) nm, and we will get the highest surface roughness values ​​at a concentration of 9%. After preparing the SiO2 nanoparticles, they are mixed with the pigment and deposited on the glass substrates using the dip-coating method to measure the contact angles and study the duration of the effect of SiO2 particles on the pigment. In addition, by measuring the contact angle between a drop of water and the coating surface, we notice that the contact angle increases after adjusting the coating by adding pure SiO2 doped with chromium and mixed with the pigment, as the contact angle increases from (95.71°) to (107.17°) depending on the surface roughness. The surface roughness and its energy are important factors affecting the contact angle.