Concomitant Effect of Quercetin- and Magnesium-Doped Calcium Silicate on the Osteogenic and Antibacterial Activity of Scaffolds for Bone Regeneration

Quercetin is a bioflavonoid which has a broad spectrum of biological activity. Due to its lower chemical stability, it is usually encapsulated, or a metal–quercetin complex is formed to enhance its biological activity at a lower concentration. Here, our novel approach was to form a quercetin complex to magnesium-doped calcium silicate (CMS) ceramics through a coprecipitation technique so as to take advantage of quercetin’s antibacterial activity within the antibacterial and osteogenic potential of the silicate. Due to quercetin’s inherent metal-chelating ability, (Ca+Mg)/Si increased with quercetin concentration. Quercetin in magnesium-doped calcium silicate ceramic showed concentration-dependent pro-oxidant and antioxidant activity in SaOS-2 with respect to quercetin concentration. By optimizing the relative concentration, we were able to achieve 3-fold higher proliferation and 1.6-fold higher total collagen at day 14, and a 1.7-fold higher alkaline phosphatase production at day 7 with respect to polycaprolactone/polyvinylpyrrolidone (PCL/PVP) scaffold. Quercetin is effective against Gram-positive bacteria such as S. aureus. Quercetin is coupled with CMS provided similar effect with lower quercetin concentration than quercetin alone. Quercetin reduced bacterial adhesion, proliferation and biofilm formation. Therefore, quercetin-coupled magnesium-doped calcium silicate not only enhanced osteogenic potential, but also reduced bacterial adhesion and proliferation.

Kinetic and Thermal Studies of Adsorption of Allura Red Dye by Surface Functionalized Magnetite Nanoparticles

In the present study, chitosan functionalized magnetite nanoparticles (CS@MNPs) were synthesized by a simple and economical coprecipitation technique for efficient magnetic removal of allura red dye (ARD) by adsorption technique from the aqueous solution. Size and surface properties of the bare and surface functionalized MNPs were determined with the help of XRD and TEM technique. Surface functionalization of the bare MNPs was confirmed with the help of FT-IR spectroscopy and TGA techniques. Magnetic properties of the synthesized bare and functionalized MNPs were determined by VSM technique. The effect of various parameters including adsorbent dosages, contact time, temperature on adsorption capacity of the CS@MNPs for allura red dye were investigated with the help of UV-vis spectrophotometer. The pseudo second order kinetics and Langmuir adsorption isotherm model were found to fitted well with the adsorption process of dye onto the chitosan functionalized magnetite nanoparticles (CS@MNPs).

Two Scenarios of Dechlorination of the Chlorinated Hydrocarbons over Nickel-Alumina Catalyst

Dechlorination processes attract great interest since they are involved in environmental protection and waste disposal technologies. In this paper, the process of gas-phase dechlorination of 1,2-dichloroethane, chloroform, and chlorobenzene over Ni/Al2O3 catalyst (90 wt% Ni) prepared by a coprecipitation technique was investigated. The reduction behavior of the oxide precursor NiO/Al2O3 was studied by thermogravimetric analysis in a hydrogen medium. A thermodynamic assessment of the conditions under which metallic nickel undergoes deactivation due to the formation of nickel chloride was performed. The dechlorination of chlorinated substrates was studied using a gravimetric flow-through system equipped with McBain balances in a wide range of temperatures (350–650 °C) and hydrogen concentrations (0–98 vol%). The impact of these parameters on selectivity towards the products of hydrodechlorination (C2H4, C2H6, and C6H6) and catalytic pyrolysis (carbon nanomaterial and CH4) was explored. The relationship between the mechanisms of the catalytic hydrodechlorination and the carbide cycle was discussed, and the specific reaction conditions for the implementation of both scenarios were revealed. According to the electron microscopy data, the carbonaceous products deposited on nickel particles during catalytic pyrolysis are represented by nanofibers with a disordered structure formed due to the peculiarity of the process including the side carbon methanation reaction.

Multifunctional Hierarchically Architectured ZnO for Luminescence, Photocatalytic, Electrocatalytic, and Energy Storage Applications

Hierarchically ZnO nanoarchitecture synthesized through coprecipitation technique. Growth process has been analyzed by varying pH from 5.5 to 13 along with post heat treatment process through the observation of surface morphology from 2D plates, triangular, hexagonal rods, needles, and finally to hierarchical. X-ray diffraction (XRD) reveals many intermediate phases along with ZnO which has been eliminated through the proper pH and temperature. The native defects have been discussed by using Raman and positron annihilation spectroscopy. Further, multifunctional properties of synthesized material have been discussed by candle-like warm white luminescence, photocatalysis, electrocatalysis and energy storage applications. Specially hierarchically nanoarchitecture found suitable for warm white lighting along with effective for waste water treatment by visible light. The highly porous property of the same material made itself appropriate for effective oxygen evaluation reaction and hydrogen evolution reaction together with reduced overpotential and Tafel slope. The application for supercapacitor electrode (~780 F/g) also has been revealed which opened new dimension for hierarchical ZnO.

Altering the properties of the magnetic Co ferrite nanoparticles fabricated by modified inverse coprecipitation for high-frequency applications

Magnetic Co ferrite nanoparticles doped with non-magnetic ions (Zn2+) fabricated by modified inverse coprecipitation technique. X-ray calculations show that the average crystallite size (D) and the average lattice constant (a) of CoZn ferrite nanoparticles increase from 32.33 to 52.87 nm and from 8.39 to 8.41Ǻ respectively with increasing non-magnetic Zn2+ ions from 0.00 to 0.55. Morphological forms and M-O at A and B sites studied by SEM and FT-IR spectroscopy. Measurements of the structural, optical, electrical and magnetic characterization of the CoZn ferrite nanoparticles strongly depend on non-magnetic Zn2+ ions content (y). Non-magnetic ions transform Co ferrite from hard and dielectric nature to soft and semiconductor nature. Values of Coercivity and the remanence decrease as non-magnetic Zn2+ ions increases to the minimum values 955 Oe and 6 emu /g for the sample with Zn = 0.55. Co0.45Zn0.55Fe2O4 is might be suitable for high-frequency applications where it has the smallest value of optical gap, the largest value of resistivity and the lowest value of dielectric loss factor.