Antimicrobial and anticoagulation activity of silver nanoparticles synthesized from the culture supernatant of Pseudomonas aeruginosa

Here, we describe biosynthesis of silver nanoparticles by reduction of aqueous Ag⁺ ions with the culture supernatant of Pseudomonas aeruginosa. The morphological, physiological, biochemical and molecular level identification of the strain GS1 resembles P. aeruginosa. The nanoparticles synthesized by P. aeruginosa were characterized by UV–vis spectroscopy, dynamic light scattering (DLS) and scanning electron microscopy (SEM). The size-distribution of nanoparticles was determined using a particle-size analyzer and the average particle-size was found to be 80 nm. The biological activities of the synthesized silver nanoparticles like antimicrobial activity were confirmed against Escherichia coli and Staphylococcus aureus and it have stable anti-coagulant effect.     

Performance Analysis of Reversed Binary Decision Diagram Pass Transistor Logic Synthesis

Binary decision diagrams (BDDs) are the most frequently used data structure for the representation and handling of Boolean functions because of their excellent time and space efficiencies. In this article, a reversed BDD‐based pass transistor logic (PTL) logic synthesis is presented for low‐power and high‐performance circuits without exploiting the canonical property of BDDs. The procedure of the reversed BDD transformation into PTL is achieved by a one‐to‐one correspondence with the BDD node and PTL cell. Layouts are generated for the benchmark circuits and simulated in terms of power dissipation, propagation delay and area. The reversed BDD technique performs better in terms of area, delay and power dissipation due to the regularity, a reduced critical path, less interconnection wires, a multiplexer‐based construction of PTL circuits, and less switching activities. Copyright © 2011 John Wiley & Sons, Ltd.     

Encrypted Network Traffic Classification and Resource Allocation with Deep Learning in Software Defined Network

Wireless Personal Communications - The climate has changed absolutely in every area in just a few years as digitized, making high-speed internet service a significant need in the future. Future...     

REDUCTION OF MACHINING VIBRATION BY USE OF RUBBER LAYERED LAMINATES BETWEEN TOOL HOLDER AND INSERT

The aim of the present study is to investigate chatter when using carbide inserts by measuring surface roughness of the workpiece. Dimensional accuracy of the workpiece is affected by vibration. In order to suppress chatter, the tool was provided with an ultra thin metal rubber laminate between the tool holder and insert. An experimental investigation has been carried out in CNC lathe using a “design of experiments” approach. In this study, vibration of the tool and surface roughness of the workpiece were measured. It has been observed that the vibration of the tool, as well as the tool insert, has been reduced by using ultra thin rubber layered laminates, and the surface finish of the workpiece has been improved.     

Remote Optical Non-Destructive Inspection Technique for Metal and Composite Structures

This paper presents a laser based non-destructive inspection technique which is purely non-contact. An acoustic device is used to remotely excite the material under inspection while a scanning laser vibrometer is employed to measure the resulting vibrations. The test materials, mostly aluminum or composite aircraft structures, have been successfully inspected from a standoff distance of at least a meter. The NDI system clearly shows the defect locations overlaid on the images of the test objects for ease of the end user. Metal and composite delamination and subsurface corrosion in aluminum structures are among the defects that were detected.     

Biocompatibility effects of biologically synthesized graphene in primary mouse embryonic fibroblast cells

Due to unique properties and unlimited possible applications, graphene has attracted abundant interest in the areas of nanobiotechnology. Recently, much work has focused on the synthesis and properties of graphene. Here we show that a successful reduction of graphene oxide (GO) using spinach leaf extract (SLE) as a simultaneous reducing and stabilizing agent. The as-prepared SLE-reduced graphene oxide (S-rGO) was characterized by ultraviolet–visible spectroscopy and Fourier transform infrared spectroscopy. Dynamic light scattering technique was used to determine the average size of GO and S-rGO. Scanning electron microscopy and atomic force microscopy images provide clear surface morphological evidence for the formation of graphene. The resulting S-rGO has a mostly single-layer structure, is stable, and has significant water solubility. In addition, the biocompatibility of graphene was investigated using cell viability, leakage of lactate dehydrogenase and alkaline phosphatase activity in primary mouse embryonic fibroblast (PMEFs) cells. The results suggest that the biologically synthesized graphene has significant biocompatibility with PMEF cells, even at a higher concentration of 100 μg/mL. This method uses a ‘green’, natural reductant and is free of additional stabilizing reagents; therefore, it is an environmentally friendly, simple, and cost-effective method for the fabrication of soluble graphene. This study could open up a promising view for substitution of hydrazine by a safe, biocompatible, and powerful reduction for the efficient deoxygenation of GO, especially in large-scale production and potential biomedical applications.     

Role of alkaline nitrites in the corrosion performance of steel in composite cements

The influence of alkaline nitrites on the inhibition of corrosion of steel in binary and ternary cement environments was tested. pH measurements carried out for binary and ternary cement extracts showed that the alkalinity of the cement was not affected by making use of binary and ternary cements. Gravimetric measurements showed that the decrease in the corrosion rate of steel in different systems follows the order: Ternary > (OPC + PSC) > (OPC + PPC) > (PPC + PSC). Potential–time studies indicated that the ability to maintain the passivity of steel in different systems also follows the order as above. Potentiodynamic polarisation studies for steel in binary and ternary cement environments showed the favourable influence of the presence of higher amounts of chlorides. Nitrites of sodium, potassium and calcium act as anodic inhibitors and they compete with chloride ions for the ferrous ions at the steel to form a film of ferric oxide. An efficiency as high as 91% is obtained for the ternary system containing 1% chloride and 0.5% nitrite. The degree of surface coverage showed a maximum value for the ternary system (>0.9) even in the presence of a higher amount of chloride thereby indicating the better performance of the system.     

Studies on phase formation,microstructure development and elastic properties of reduced NiO–8YSZ anode supported bi-layer half-cell structures of solid oxide fuel cells

Half-cell structures of solid oxide fuel cells (SOFCs) with a thin and dense electrolyte layer of 8YSZ supported by a thick and porous NiO–8YSZ anode precursor structure were reduced in a gas mixture of 5% H₂–95% Ar at 800 °C for selected time periods in order to fabricate cermets with desired microstructure and composition, and to study their effects on the elastic properties at ambient and reactive atmospheres. It appears that 2 h of exposure to the reducing conditions is enough to reduce ～80% of NiO with an enhanced porosity value of 35%. The Ni–8YSZ cermet phase formation in the anode was analyzed with X-ray diffraction (XRD) in correlation with its microstructure. The elastic properties were determined after the reduction, at room and elevated temperatures using the impulse excitation technique. At room temperature the decrease in the Young's modulus was about 44% (after 8 h of reduction) and can be attributed mainly to the changes in the microstructure, particularly the increase in porosity from ～12% to 37%. Young's moduli of the as-received precursor and reduced anodes were evaluated as a function of temperature in air and reducing atmosphere. The results were explained in correlation to the initial porosity, composition and oxidation of Ni at the elevated temperatures.     

Characterization of reduced graphene oxide obtained from vacuum-assisted low-temperature exfoliated graphite

Microsystem Technologies - Graphene consists of sheets of two-dimensional allotrope carbons and is a basic element of graphite. Herein, reduced graphene oxide (rGO) were exfoliated from graphite...