Unsteady three dimensional flow of couple stress fluid over a stretching surface with chemical reaction

The unsteady three-dimensional flow of couple stress fluid over a stretched surface is investigated. Analysis has been performed in the presence of mass transfer and chemical reaction. Nonlinear flow analysis is computed by a homotopic approach. Plots are presented and analyzed for the various parameters of interest. A comparative study with existing solutions in a limiting sense is made

Slip and Heat Transfer Effects on Peristaltic Motion of a Carreau Fluid in an Asymmetric Channel

An analysis has been carried out for peristaltic flow and heat transfer of a Carreau fluid in an asymmetric channel with slip effect. The governing problem is solved under long wavelength approximation. The variations of pertinent dimensionless parameters on temperature are discussed. Pumping and trapping phenomena are studied

Characterization of silver nanoparticles prepared by wet chemical method and their antibacterial and cytotoxicity activities

Purpose: To investigate the efficiency of silver nanoparticles synthesized by wet chemical method, and evaluate their antibacterial and anti-cancer activities.Methods: Wet chemical method was used to synthesize silver nanoparticles (AgNPs) from silver nitrate, trisodium citrate dehydrate (C6H5O7Na3.2H2O) and sodium borohydride (NaBH4) as reducing agent. The AgNPs and the reaction process were characterized by UV–visible spectrometry, zetasizer, transmission electron microscopy (TEM) and scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS). The antibacterial and cytotoxic effects of the synthesized nanoparticles were investigated by agar diffusion method and MTT assay respectively.Results: The silver nanoparticles formed were spherical in shape with mean size of 10.3 nm. The results showed good antibacterial properties, killing both Gram-positive and Gram-negative bacteria, and its aqueous suspension displayed cytotoxic activity against colon adenocarcinoma (HCT-116) cell line.Conclusion: The findings indicate that silver nanoparticles synthesized by wet chemical method demonstrate good cytotoxic activity in colon adenocarcinoma (HCT-116) cell lines and strong antibacterial activity against various strains of bacteria.Keywords: Wet chemical, Silver nanoparticles, Characterization, Diffusion method, Antibacterial, Cytotoxic activit

Novel Green Synthesis and Characterization of Nanopolymer Porous Gold Oxide Nanoparticles

Purpose: To develop a novel approach to green synthesis of nano-polymer porous gold oxide nanoparticles, and examine the effects of the temperatures on their surface.Methods: Green synthesis of nano-polymer porous gold oxide nanoparticles (GONPs) using cetyle trimethylammonium bromide (CTAB) surfactant with a mixture of Olea europaea fruit and Acacia Nilotica extracts, was performed using sol-gel method. The nanoporous particles were characterized by UV (ultraviolet (UV) visible spectroscopy and dynamic light scattering (DLS) while a zetasizer was applied to determine their average particle size. Their surface morphology and shape were assessed by transmission electron microscopy (TEM) and scanning election microscopy (SEM) while surface area was measured using nitrogen gas adsorption method.Results: TEM and SEM images showed a smooth, cylindrical or spherical, and cluster shapes, and porous surface morphology. Increase in calcination temperature resulted in increase in surface area and pore volume of nanoparticles. This feature yielded GONPs that were unique with a high surface area of 146.706 m2/g.Conclusion: The approach used in this study constitutes a new and rapid green synthesis of porous nanoparticles of gold oxide under simple conditions. Furthermore, increase in GONPs surface area is enhanced by increase in calcination temperature.Keywords: Gold oxide, Nanoporous, Green synthesis, Olea europaea, Acacia Nilotica, Surface area, Nanopolymer, Surface morpholog

Slip Effects on Peristaltic Transport in an Inclined Channel with Mass Transfer and Chemical Reaction

An analysis is carried out for the peristaltic flow in an inclined asymmetric channel when no-slip condition does not hold. The whole analysis has been carried out in the presence of mass transfer and chemical reaction. The channel asymmetry is generated because of peristaltic wave train on the walls through different amplitudes and phases. Long wavelength and low Reynolds number assumption is adopted in the whole mathematical analysis. Expressions for the stream function and longitudinal pressure gradient have been developed. Numerical integration is performed for the analysis of pressure rise per wavelength. Longitudinal velocity, pumping and trapping phenomena are analyzed in detail via plots

Preparation, characterization and antibacterial effects of eco-friendly gold nanorods

Purpose: To synthesize and characterize eco-friendly gold nanorods (Au-NRs) and to assess their effects against two bacterial strains.Methods: Synthesis of eco-friendly gold nanorods was done from an aqueous solution of chloroauric acid and cetyltrimethylammonium bromide by mixing Olea europaea fruit and Acacia nilotica husk extracts with the latter as a reducing agent. The synthesis was monitored by ultraviolet–visible (UV) spectrophotmetry and a zetasizer, while the morphology of the resulting nanorods was assessed by transmission electron microscopy (TEM) and scanning electron microscopy (SEM) coupled with an energy-dispersive spectrophotometer (EDS). The effect of the prepared eco-nanorods on growth of Escherichia coli and Staphylococcus aureus bacteria were investigated by agar diffusion method.Results: The synthesized Au-NRs were mostly rod-shaped, with mean size of 96 nm. They exhibited a potent antibacterial activity against Gram-positive and  Gram-negative microorganisms (Escherichia coli and Staphylococcus aureus).Conclusion: The findings suggest that the nanoformulation of the biomaterial mix of Olea europaea fruit and Acacia nilotica husk extracts is a cost-effective, eco-friendly, and non-toxic synthesis of Au- NRs which has therpeautic potential.Keywords: Olea europaea, Acacia nilotica, Gold nanorods, Eco-friendly synthesis, Gram-positive and Gram-negative microorganism

Green Synthesis, Characterization, and Antibacterial Activity of Silver/Polystyrene Nanocomposite

A novel, nontoxic, simple, cost-effective and ecofriendly technique was used to synthesize green silver nanoparticles (AgNPs). The AgNPs were synthesized using orange peel extract as a reducing agent for silver nitrate salt (AgNO3). The particle size distribution of AgNPs was determined by Dynamic Light Scattering (DLS). The average size of silver nanoparticles was 98.43 nm. The stable dispersion of silver nanoparticles was added slowly to polystyrene solution in toluene maintaining the temperature at 70°C. The AgNPs/polystyrene (PS) nanocomposite solution was cast in a petri dish. The silver nanoparticles encapsulated within polymer chains were characterized by X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM) equipped with Energy Dispersive Spectroscopy (EDS) in addition to Transmission Electron Microscopy (TEM). The green AgNPs/PS nanocomposite film exhibited antimicrobial activity against Gram-negative bacteria Escherichia coli, Klebsiella pneumoniae and Salmonella, and Gram-positive bacteria Staphylococcus aureus. Thus, the key findings of the work include the use of a safe and simple AgNPs/PS nanocomposite which had a marked antibacterial activity which has a potential application in food packaging

New Exact Travelling Wave Solutions for some Nonlinear Evolution Equations

In this paper sub-equation method with symbolic computational method is used for constructing the new exact travelling wave solutions for some nonlinear evolution equations arising in mathematical physics namely,the WBK, Z–K equation, and coupled nonlinear equations . As a result,the traveling wave solutions are obtained include, solitons, kinks and plane periodic solutions. It worthwhile to mention that the proposed method can be applied in further works to establish more entirely new exact solutions for other kinds of nonlinear evolution equation

Silver nanoparticles mediate differential responses in some of liver and kidney functions during skin wound healing

Abstract Silver has been used for the treatment of medical ailments for over 100 years due to itsnatural antibacterial and antifungal properties. In this study, silver nanoparticles were synthesized,evaluated for its wound healing activity and its effect in some functions of the liver and kidney. Weinvestigated the wound-healing properties of silver nanoparticles in an animal model and found thatrapid healing and improved cosmetic appearance occur within 15 days. Furthermore, we showedthat silver nanoparticles exert positive effects through their antimicrobial properties, reduction inwound inflammation, and modulation in some of liver and kidney functions during skin woundhealing. These results have given insight into the actions of silver and have provided a novel therapeuticdirection for wound treatment in clinical practic