Context. Many diseases are associated with oxidative stress caused by free radicals. Objective. The present study evaluated the in vitro antioxidant and antibacterial activities of various extracts of aerial parts of Periploca aphylla and Ricinus communis. Materials and Methods. In vitro antioxidant activities of the plant extract were determined by DPPH and NO scavenging method. Superoxide anion radical activity was measured by the reduction of nitro blue tetrazolium as compared with standard antioxidants. Total phenolic contents and antibacterial activities of these plants were determined by gallic acid equivalent (GAE) and serial tube dilution method, respectively. Results. Plants showed significant radical scavenging activity. The results were expressed as IC50. n-Propyl gallate and 3-t-butyl-4-hydroxyanisole were used as standards for antioxidant assay. All the extracts of both plants showed comparable IC50 to those of standards. Plants extract exhibited high phenolic contents and antibacterial activities were comparable with standard drug, Ciprofloxacin. Discussion and Conclusion. The present study provides evidence that Periploca aphylla and Ricinus communis prove to be potent natural antioxidants and could replace synthetic antioxidants. Plants can also be used against pathogenic bacterial strains.

In this work, we report the synthesis of composite system pNAC, composed of silver nanoparticles embedded in pure thermo-sensitive crosslinked polymer network of poly(N-isopropylacrylamide-co-acrylamide) (pNA), using as a catalyst for the reduction of methylene blue (MB) dye by sodium borohydride (NaBH 4 ). The pNA was prepared by conventional free radical polymerization technique using sodium dodecyl sulfate as stabilizing agent, followed by in situ reduction of AgNO 3 inside the polymer network by NaBH 4 for the synthesis of composite systems pNACs. The synthesized pNA and pNACs were characterized by FTIR, dynamic light scattering, thermogravimetric analysis, scanning electron microscopy and UV-visible spectroscopy techniques. The materials were found sensitive toward temperature change of the medium. The entrapment ability of pNA toward different amounts of AgNO 3 solution was studied, and effect of metal content on particle size of pNACs was analyzed. The pNACs were applied as a catalyst for the reduction of MB in which they exhibit high catalytic activity and reusability toward the reaction.

The binary nanocomposite (BNC) was synthesized by using SnCl 2 •5H 2 O and C 12 H 28 O 4 Ti precursors and characterized by Brunauer− Emmett−Teller analysis, X-ray diffraction, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis, Fouriertransform infrared spectroscopy, and transmission electron microscopy. The characterization results confirm the successful synthesis of binary nanocomposite with size of about 15 nm. The synthesized binary nanocomposite (BNC) was evaluated for lead ions (Pb 2+ ) removal from aqueous solution and antimicrobial activities. The maximum adsorption capacities of 68.36, 68.81, and 70.01 mgg −1 of lead (Pb 2+ ) ions were detected at 293, 303, and 313 K, respectively. Both the Langmuir and Freundlich models were applied to the adsorption data, and the high regression value (R 2 ) suggests that the Langmuir model describes the adsorption data better than the Freundlich model. The q m and K b values revealed that the binary nanocomposite exhibits good adsorption capacity for lead (Pb 2+ ) ions. Moreover, it was also observed that the binary nanocomposite bears good antimicrobial activities against selected stains.

In binary system consisting only of the oppositely charged surfactants, a single type of aggregates (mostly probably vesicles) was identified. Upon polymer addition, a shift in aggregation concentration was observed; however, no additional clustering occurred and single inflection point was visible in all property versus concentration plots. The binding behavior in ternary mixtures comprising of poly (ethylene oxide), sodium dodecyl sulfate, and acetyl trimethyl ammonium bromide has been studied by using conductivity. The aggregation and binding phenomena were thermodynamically feasible, unraveled by the negative values of Gibbs free energy. An increased amount of adsorbed poly (ethylene oxide) caused an increase in these values, showing an alteration in interfacial free energy due to release of water molecules from vesicles' surface. The area per molecule calculated for ternary system indicted the existence of compact packing in mixed clusters.

The main objective of this research work is to explore the complete and extensive rheological studies of cationic poly (3-acrylamidopropyl trimethyl ammonium chloride) P(APTMACl) hydrogel, prepared by free radical polymerization method at room temperature. Hydrogel was characterized by various techniques such as SEM, FTIR and TGA, whereas rheological properties of synthesized hydrogel were obtained using frequency sweep and frequency curve analysis in different temperature range. Storage modulus (G′) and loss modulus (G′′) were investigated as a function of angular frequencies and shear stress at various temperatures. Rheological models like Bingham plastic model, modified Bingham and Ostwald power law were applied to understand the rheological performance of the gels. Flow curves obtained at different temperatures indicate that P(APTMACl) hydrogel shows a non-Newtonian pseudo plastic behavior. All results concluded that rheology is a powerful tool to study the complete visco-elastic behavior of polymer hydrogel for multiple applications.