Determination of chemical profile, antioxidant, DNA damage protection and antiamoebic activities of Teucrium polium and Stachys iberica

This work deals with the evaluation of in vitro antioxidant, DNA preventing and antiamoebic activities of the water extracts of Teucrium polium and Stachys iberica. In all systems, T. polium extract exhibited excellent activity potential than that of S. iberica. The amount of total phenolics and flavonoids were high in this extract. In the presence of 40 mg/ml T. polium extract, a significant protection was observed for native super coiled DNA of pBR322 plasmid DNA. In the presence of 32 mg/ml of T. polium extract, no trophozoite was after the 24th hour.     

Experimental observation of nonlinear traveling waves in turbulent pipe flow

Transition to turbulence in pipe flow is one of the most fundamental and longest-standing problems in fluid dynamics. Stability theory suggests that the flow remains laminar for all flow rates, but in practice pipe flow becomes turbulent even at moderate speeds. This transition drastically affects the transport efficiency of mass, momentum, and heat. On the basis of the recent discovery of unstable traveling waves in computational studies of the Navier-Stokes equations and ideas from dynamical systems theory, a model for the transition process has been suggested. We report experimental observation of these traveling waves in pipe flow, confirming the proposed transition scenario and suggesting that the dynamics associated with these unstable states may indeed capture the nature of fluid turbulence.     

Graphene Oxide/Alginate Quasi-Cryogels for Removal of Methylene Blue

Quasi-cryogelation technique is a simple yet effective technique for improving the adsorptive efficiency of biopolymer-based adsorbent materials. In this work, a biopolymer-based adsorbent material, graphene oxide alginate quasi-cryogel beads are reported. Alginate biopolymer was crosslinked and frozen at ??21 °C in order to obtain a gel with cryogel-like microstructure. Graphene oxide was included in the bead formulation in order to enhance the adsorptive characteristics. Beads were characterized using Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and swelling experiments. Removal of the model cationic dye, methylene blue, was studied by batch adsorption method. It is found that the adsorption follows the Freundlich isotherm model and pseudo-first order kinetics with reaching an adsorption capacity of 122.26 mg/g in 60 min. Results indicate that the physisorption might be due to the π–π interactions between graphene oxide and methylene blue, in addition to electrostatic interactions. Moreover, quasi-cryogelation technique significantly improved the dye removal properties.