Biofabrication of broad range antibacterial and antibiofilm silver nanoparticles

Silver nanoparticles (AgNPs) were biosynthesized via a green route using ten different plants extracts (GNP1‐ Caryota urens, GNP2‐Pongamia glabra, GNP3‐ Hamelia patens, GNP4‐Thevetia peruviana, GNP5‐Calendula officinalis, GNP6‐Tectona grandis, GNP7‐Ficus petiolaris, GNP8‐ Ficus busking, GNP9‐ Juniper communis, GNP10‐Bauhinia purpurea). AgNPs were tested against drug resistant microbes and their biofilms. These nanoparticles (NPs) were characterised using UV‐vis spectroscopy, transmission electron microscope, Fourier transform infrared spectroscopy, X‐ray diffraction and Image J software. Most of the AgNPs were distributed over a range of 1 of 60 nm size. The results indicated that AgNPs were antibacterial in nature without differentiating between resistant or susceptible strains. Moreover, the effect was more prominent on Gram negative bacteria then Gram positive bacteria and fungus. AgNPs inhibited various classes of microbes with different concentration. It was also evident from the results that the origin or nature of extract did not affect the activity of the NPs. Protein and carbohydrate leakage assays confirmed that the cells lysis is one of the main mechanisms for the killing of microbes by green AgNPs. This study suggests that the action of AgNPs on microbial cells resulted into cell lysis and DNA damage. Excellent microbial biofilm inhibition was also seen by these green AgNPs. AgNPs have proved their candidature as a potential antibacterial and antibiofilm agent against MDR microbes.Inspec keywords: silver, nanoparticles, antibacterial activity, nanofabrication, microorganisms, ultraviolet spectra, visible spectra, transmission electron microscopy, Fourier transform infrared spectra, X‐ray diffraction, proteins, DNA, nanomedicine, biomedical materials, cellular biophysicsOther keywords: biofabrication, broad range antibacterial nanoparticles, antibiofilm silver nanoparticles, plant extract contribution, drug resistant microbes, UV‐vis spectroscopy, transmission electron microscope, Fourier transform infrared spectroscopy, X‐ray diffraction, Image J software, resistant strains, susceptible strains, Gram positive bacteria, fungus, protein leakage assays, carbohydrate leakage assays, cell lysis, DNA damage, Ag     

Biomimetic production,characterisation, in vitro cytotoxic and anticancer assessment of aqueous extract‐mediated AgNPs of Teucrium stocksianum Boiss

Owing to the numerous biological applications, cost effectiveness and low cytotoxicity of the biomimetic nanoparticles (NPs), the authors optimised the production of silver NPs (AgNPs) using aqueous extract of Teucrium stocksianum Boiss. The NPs were characterised by ultraviolet‐visible (UV‐vis) spectroscopy, X‐ray diffraction (XRD), scanning electron microscopy (SEM), dynamic light scattering (DLS) and Fourier transform‐infrared spectroscopy (FTIR). The UV‐vis spectroscopy revealed a surface plasmon resonance (410‐440 nm) at an incubation temperature of 90°C when 1 mM Ag nitrate combined to 5 mg/ml extract concentration in the ratio of 1:10. DLS results show an average zeta size of ∼44.61 nm and zeta potential of −15.3 mV. SEM and XRD confirmed the high crystallinity and cubical symmetry with an average size below 100 nm. FTIR measurement shows the presence of various functional groups, responsible for the capping and reduction of Ag metal. The 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide cell viability assay shows that AgNPs are less cytotoxic to J774 and L929 cells as compared with enhanced anticancer activity with low IC50 concentrations (68.24 µg/ml) against Michigan Cancer Foundation‐7 (MCF‐7) cells. The ethidium bromide/acridine orange assay shows that the AgNPs kill the cell by apoptosis. Overall, the results show that AgNPs possesses potent anticancer activities.Inspec keywords: cellular biophysics, cancer, nanobiotechnology, nanomedicine, ultraviolet spectra, X‐ray diffraction, scanning electron microscopes, light scattering, patient treatmentOther keywords: anticancer assessment, in vitro cytotoxic assessment, aqueous extract‐mediated AgNPs, Teucrium stocksianum Boiss, nanoparticles, biological applications, biosynthesis, silver NPs, X‐ray diffraction, scanning electron microscopy, dynamic light scattering, Fourier transform‐infrared spectroscopy, UV‐vis spectroscopy, surface plasmon resonance, extract concentration, zeta potential, high crystallinity, FTIR measurement, amide molecules, viability assay, enhanced anticancer activity, potent anticancer activities     

Frequency Reconfigurable Antenna for Portable Wireless Applications

In this paper, the design and experimental evaluation of a hexagonal-shaped coplanar waveguide (CPW)-feed frequency reconfigurable antenna is presented using flame retardant (FR)-4 substrate with size of 37 × 35 × 1.6 mm³. The antenna is made tunable to three different modes through the status of two pin diodes to operate in four distinct frequency bands, i.e., 2.45 GHz wireless fidelity (Wi-Fi) in MODE 1, 3.3 GHz (5G sub-6 GHz band) in MODE 2, 2.1 GHz (3G Long Term Evolution (LTE)-advanced) and 3.50 GHz Worldwide Interoperability for Microwave Access (WiMAX) in MODE 3. The optimization through simulation modeling shows that the proposed antenna can provide adequate gain (1.44~2.2 dB), sufficient bandwidth (200~920 MHz) and high radiation efficiency (80%~95%) in the four resonating frequency bands. Voltage standing wave ratio (VSWR) < 1.5 is achieved for all bands with properly matched characteristics of the antenna. To validate the simulation results, fabrication of the proposed optimized design is performed, and experimental analysis is found to be in a considerable amount of agreement. Due to its reasonably small size and support of multiple frequency bands operation, the proposed antenna can support portable devices for handheld 5G and Wireless LAN (WLAN) applications.     

Polymer-coated CoFe<Subscript>2</Subscript>O<Subscript>4</Subscript> nanoassemblies as biocompatible magnetic nanocarriers for anticancer drug delivery

In this work, we report the preparation of cobalt ferrite nanoparticles (CFNPs) coated with hydrophilic polymers guar gum, gum arabic and poly (methacrylic acid) as magnetic nanocarriers and study their conjugation with doxorubicin for the drug release under applied magnetic field. The effect of polymer coating on structural properties is studied using Fourier transform infrared spectroscopy and powder X-ray diffractometry (XRD). The XRD analysis revealed that the polymer coating on the as-synthesized CFNPs has no influence on their crystallite size and it remains between 18 nm and 19 nm. The characteristic morphology, topography and the evidences of polymer coating over the CFNPs are investigated using scanning electron microscopy, atomic force microscopy and thermogravimetric analysis, respectively. Vibrating sample magnetometry revealed the ferromagnetic nature of uncoated CFNPs with a significant saturation magnetization ～77.2 emu g^?1. The dynamic light scattering measurements are also performed to determine the size of uncoated and coated CFNPs. UV–Visible spectroscopy demonstrated a profound loading (70–75%) of doxorubicin onto the magnetic nanocarriers and the efficient release of drug in the presence of external applied magnetic field. In vitro cytotoxic studies confirmed the cytocompatibility mode of coated CFNPs against Chinese Hamster Ovary and Huh-7 cell line, while 0.2 mg mL^?1 dose of drug-loaded magnetic nanocarriers inhibited the cell viability of Huh-7 up to 60%. These results strongly encourage the utilization of biocompatible magnetic nanocarriers in targeted drug delivery territory.     

Synthesis and characterization of ZnO nanostructures with varying morphology

Uniform fine particles of zinc oxide were prepared in three different morphologies and sizes by the controlled precipitation process from aqueous solutions of zinc nitrate in the presence of ethylene glycol. Ammonium hydroxide solution was used as the precipitant. Composition of the reactant solution, pH and temperature significantly affected the particle uniformity with respect to shape and size. Uniformity in the particles morphological feature was achieved under a narrow set of experimental conditions. pH of the reactant solutions and isoelectric point of zinc oxide were considered the master variables, controlling the particle size. One of the batch of the as-prepared zinc oxide particles was calcined at \(750{^{\circ }}\hbox {C}\), which increased its crystallinity, changed its various lattice parameters, Zn–O bond length and preferred orientation of the crystal hkl planes. Calcination had little effect on the original morphology of the zinc oxide particles.     

Statistical modelling for falls count data

Falls and their injury outcomes have count distributions that are highly skewed toward the right with clumping at zero, posing analytical challenges. Different modelling approaches have been used in the published literature to describe falls count distributions, often without consideration of the underlying statistical and modelling assumptions. This paper compares the use of modified Poisson and negative binomial (NB) models as alternatives to Poisson (P) regression, for the analysis of fall outcome counts. Four different count-based regression models (P, NB, zero-inflated Poisson (ZIP), zero-inflated negative binomial (ZINB)) were each individually fitted to four separate fall count datasets from Australia, New Zealand and United States. The finite mixtures of P and NB regression models were also compared to the standard NB model. Both analytical (F, Vuong and bootstrap tests) and graphical approaches were used to select and compare models. Simulation studies assessed the size and power of each model fit. This study confirms that falls count distributions are over-dispersed, but not dispersed due to excess zero counts or heterogeneous population. Accordingly, the P model generally provided the poorest fit to all datasets. The fit improved significantly with NB and both zero-inflated models. The fit was also improved with the NB model, compared to finite mixtures of both P and NB regression models. Although there was little difference in fit between NB and ZINB models, in the interests of parsimony it is recommended that future studies involving modelling of falls count data routinely use the NB models in preference to the P or ZINB or finite mixture distribution. The fact that these conclusions apply across four separate datasets from four different samples of older people participating in studies of different methodology, adds strength to this general guiding principle.     

Ultra-Wideband Antenna Development to Enhance Gain for Surface Penetrating Radar

Wireless Personal Communications - The rapid procreation of internet of things (IoT) has invigorated massive research efforts with the purpose to save and use the lifetime of battery-powered sensor...     

Optimal quantum well width and the effect of quantum well position on the performance of transistor lasers

Transistor laser (TL) model based on InGaP/GaAs/InGaAs/GaAs is analyzed and presented. It is realized that quantum well (QW) with width of 10 nm may be formed for low base threshold current density J th . The emission wavelength is found to be 1.05 μm, and the indium (In) composition is 0.25 for optimal QW width. It is identified that J th decreases with the movement of QW towards the base-emitter (B-E) interface. Small signal optical response is calculated, and the effect of QW position is studied. The bandwidth is enhanced due to the movement of the QW towards the emitter base junction.