Synergistic evaluation of AgO2 nanoparticles with ceftriaxone against CTXM and blaSHV genes positive ESBL producing clinical strains of Uro‐pathogenic E. coli

The silver oxide nanoparticles (AgO₂ ‐NPs) were synthesised using silver foil as a new precursor in wet chemical method. X‐ray diffraction analysis shows crystallographic structures of AgO₂ ‐NPs with crystallite size of 35.54 nm well‐matched with standard cubic structure. Scanning electron microscopy analysis clearly shows the random distribution of spherical‐shaped nanoparticles. Energy dispersive X‐ray analysis confirmed the purity of the samples as it shows no impurity element. Fourier transforms infra‐red analysis confirmed the formation of AgO₂ ‐NPs with the presence of Ag‐O‐Ag stretching bond. All the techniques also confirmed the loading of ceftriaxone drug on the surface of AgO₂ ‐NPs. This study also described the effect of AgO₂ ‐NPs having synergistic activity with β lactam antibiotic i.e. ceftriaxone against ESBL generating Escherichia coli (E. coli). Among isolated strains of E. coli, 60.0% were found to be ESBL producer. The synergistic activities of AgO₂ ‐NPs with ceftriaxone suggest that these combinations are effective against MDR‐ESBL E. coli strains as evident by increase in zone sizes. The present study observed rise in MDR‐ESBL E. coli with polymorphism of blaCTXM and blaSHV causing UTI infections in Pakistani population. The antibiotic and AgO₂ ‐NPs synergistic effect can be used as an efficient approach to combat uro‐pathogenic infections.Inspec keywords: antibacterial activity, nanofabrication, nanomedicine, drugs, nanoparticles, microorganisms, crystallites, scanning electron microscopy, silver compounds, X‐ray diffraction, X‐ray chemical analysis, Fourier transform infrared spectra, organic compounds, geneticsOther keywords: synergistic evaluation, clinical strains, silver oxide nanoparticles, silver foil, wet chemical method, X‐ray diffraction analysis, crystallographic structures, standard cubic structure, spherical‐shaped nanoparticles, energy dispersive X‐ray analysis, ceftriaxone drug, synergistic activity, ESBL producer, scanning electron microscopy, Fourier transform infrared analysis, Escherichia coli, blaSHV gene positive ESBL, crystallite size, random distribution, β lactam antibiotics, MDR‐ESBL E. coli strains, polymorphism, blaCTXM, uro‐pathogenic infections, uro‐pathogenic E. coli, AgO₂      

Classification of M-QAM and M-PSK signals using genetic programming (GP)

With the popularity of software-defined radio and cognitive radio-technologies in wireless communication, radio frequency devices have to adapt to changing conditions and adjust its transmitting parameters such as transmitting power, operating frequency, and modulation schemes. Thus, automatic modulation classification becomes an essential feature for such scenarios where the receiver has a little or no knowledge about the transmitter parameters. This paper presents kth nearest neighbor (KNN)-based classification of M-QAM and M-PSK modulation schemes using higher-order cumulants as input features set. Genetic programming is used to enhance the performance of the KNN classifier by creating super features from the data set. Simulation result shows improved accuracy at comparatively lower signal-to-noise ratio for all the considered modulations.

     

Effect of Ti interlayer on corrosion behavior of nanostructured Ti/TiN multilayer coating deposited on TiAl6V4

To improve the corrosion properties of TiAl₆V₄ alloy, TiN monolayer and Ti/TiN multilayer coatings are deposited by reactive magnetron sputtering. The phase, structure, and morphology properties are investigated by grazing‐incidence X‐ray diffraction, field‐emission scanning electron microscopy, and atomic force microscopy, respectively, and the corrosion behavior is evaluated by electrochemical impedance spectroscopy and potentiodynamic polarization. The TiN monolayer and Ti/TiN multilayer with thickness of 1,350 and 1,410 nm have the (111) and (002) preferred orientation and crystallite size of 42.5 and 24.3 nm, respectively. Columnar growth in TiN is hindered by the Ti interlayers and no cracking is observed between the layers indicating strong adhesion. The nanostructured Ti/TiN coating forms stable surface titanium oxide which improves the corrosion resistance by approximately 80 and four times compared with TiAl₆V₄ alloy and TiN coating, respectively. Hindrance of the columnar structure in TiN by the Ti interlayer decreases the local corrosion rate and enhances the galvanic corrosion resistance by forming a layer on the β‐phase enriched with vanadium as well as a TiO₂ stable layer. The nanostructured Ti/TiN coating demonstrates capacitive behavior with phase angles approximately ?50° and high impedance values at low frequency to be the corrosion resistance mechanism.     

Implementation of IEEE 802.16e Standard on Xilinx ZC706: A C-RAN Prototype

Wireless Personal Communications - In this paper, we propose an architecture to implement IEEE 802.16e transmitter and receiver physical (PHY) layer on field programmable gate arrays. Several...     

Negative zero-field-cooled magnetization and magnetic switching in multiferroic Lu0.5Sc0.5FeO3 ceramics

In this study, we have investigated the negative magnetization of Lu_0.5Sc_0.5FeO₃ (LSFO) ceramics in the zero-field-cooled (ZFC) mode. The negative magnetization in ZFC measurement appears below the Neél temperature (T_N) in LSFO, which is probably caused by the residual negative trapping field in superconducting magnet, and is closely related to the giant coercivity in LSFO. By fitting the high-temperature paramagnetic data under nominal zero magnetic field, the negative trapping field in superconducting magnet is found to be −3.28 Oe. The giant coercivity is ascribed to the strong uniaxial magnetocrystalline anisotropy in LSFO, which can cause the strong magnetic domain wall pinning effect to limit the nucleation of reversed domains under reverse field. In addition, a switchable magnetization switching is realized in LSFO. The magnetization of LSFO can stably switch between positive and negative values when the applied magnetic field was switched between 0.5 and 3 kOe, which suggests that the LSFO samples are suitable for potential applications in magnetic storage.     

Thermoelastic vibration of doubly-curved nano-composite shells reinforced by graphene nanoplatelets

Abstract

The thermo-mechanical vibration characteristics of doubly-curved nano-composite shells reinforced by graphene nanoplatelets are investigated by considering a uniform distribution of graphene and a first-order shear deformation theory. The mechanical properties of the nano-composite shells are estimated by using the modified Halpin–Tsai model. The governing equations are first derived by a variational formulation using Hamilton’s principle and are solved using the Galerkin technique. Numerical results are presented for various shell curvatures and compared with those available in the archival literature. Furthermore, parametric studies are offered to highlight the significant influence of graphene nanoplatelets’ weight fraction, dimensions of graphene nanoplatelets, and temperature variation, on the free vibration of the nano-composite shells.     

Experimental study and FEM analysis of redundant strains in flow forming of tubes

Flow forming, as a kind of metal spinning processes, is mainly used to produce thin-walled high-precision tubular components. In this study a coupled set of experiments and numerical simulations using the commercial finite element code ABAQUS/Explicit was used to study the evolution of redundant strains in a single-roller flow forming process in one pass. The modified embedded pins were used to evaluate the shear strains. It is shown that high shear strains occur not only at the longitudinal but also at the cross section. Sketched longitudinal lines also show that ?_θz of the cylindrical coordinate system cannot be neglected. Beside of the shear strains, reversal straining is recognized as another type of redundant work. It is shown that this type of redundant strain results from the incremental nature of flow forming process in which the deformation is highly localized. Good agreements between the force measurements of frictionless model simulations with the experiment imply that the frictional work can be neglected in comparison to the redundant work.     

Effect of pH on Aerobic Granulation and Treatment Performance in Sequencing Batch Reactors

Two sequencing batch reactors were operated to investigate the effect of influent alkalinity and reactor pH on aerobic granulation. In the first reactor R1 with high influent alkalinity the pH was adjusted in the neutral range, and in the second reactor R2 with low alkalinity the pH was held within the acidic range. The R1‐dominating species were bacteria and the appearance time of granules was three weeks after reactor start‐up. On the other hand, the acidic environment of R2 provided favorable conditions for fungal growth, and rapid granule formation occurred within the first week of operation. The varying microbial structure of granules resulted in different reactor performance in terms of evolution time and morphology of granules, suspended solids in the reactors, settling ability of granules, effluent quality of treated wastewater, and physical strength of the granules.     

Quantification and Compositional Diversity of Fatty Acid Methyl Esters Profile in Nigella sativa L. Germplasm

Nigella sativa L. is an annual underutilized crop of enormous significance, it contains more than 100 bioactive constituents having both pharmaceutical and industrial applications. Nigella sativa L. germplasm consisting of 32 genotypes was quantified for palmitic acid, stearic acid, oleic acid, linoleic and linolenic acid and results obtained varied in percentage. Lipid extracted by chloroform methanol 2:1 (24–37 %) was higher compared to n-hexane (18–35 %) and chloroform methanol 1:3 (18–34 %). Extraction with solvent chloroform methanol 2:1 yielded a higher quantity of oil contents, hence recommended. The polyunsaturated fatty acids were higher than monounsaturated fatty acids. Stearic and palmitic acids were positively correlated as were stearic and linoleic acids. It is inferred that breeding for increased stearic acid, linolenic acid and reduced palmitic acid can be achieved through modern breeding methods. The genotypes rich in oil and oleic-linoleic acid, viz., Pk-020545, Pk-020576, Pk-020609, Pk-020620, Pk-020654, Pk-020699, Pk-020720, Pk-020780, Pk-020874 and Pk-020878, have been suggested for crop improvement programs and could augment the supply of edible oil as well as a biofuel substitute with large scale cultivation.     

Poly(lactic acid) stereocomplex formation: Application to PLA rheological property modification

Poly(lactic acid) (PLA) stereocomplex formation in isothermal conditions in the absence and presence of a nucleating agent was studied from a rheological point of view due to sensitivity of viscoelastic properties to structural changes during this process. PDLA was melt blended in low concentrations with PLLA to produce a stereocomplex. Amorphous samples were prepared and crystallization was carried out in a rheometer at high temperatures to simulate melt processing conditions. Stereocomplexation was explored over time by measuring rheological parameters in small deformation oscillatory shear mode at a low frequency using parallel plate geometry. Kinetic data obtained by this means was compared to data from calorimetric studies, showing a different trend depending on the characterization method. Moreover, after the completion of crystallization, final crystalline structure was probed over a wide range of frequencies to investigate the rheological modification role of PDLA on PLLA major component. Differences in rheological characteristics of asymmetric PLLA/PDLA blends as compared to neat PLLA were associated to the structural changes happening because of the formation of the stereocomplex. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41073.