Unveiling the cytotoxicity of phytosynthesised silver nanoparticles using Tinospora cordifolia leaves against human lung adenocarcinoma A549 cell line

Biosynthesis of silver nanoparticles (AgNPs) using plant extract is a cheap, easily accessible and natural process in which the phyto‐constituents of the plants act as capping, stabilising and reducing agent. The present study explored the biosynthesis of AgNPs using aqueous leaf extract of Tinospora cordifolia and characterised via various techniques such as Fourier transform infrared, scanning electron microscopy, transmission electron microscopy (TEM), energy dispersive X‐ray analysis and X‐ray diffraction. Here, TEM confirmed the spherical morphology with 25–50 nm size of synthesised AgNPs. Further, anticancer efficiency of AgNPs synthesised using T. cordifolia leaves were evaluated against human lung adenocarcinoma cell line A549 by MTT, trypan blue assay, apoptotic morphological changes using Annexin V‐FITC and Propidium iodide (PI), nuclear morphological changes by DAPI (4, 6‐diamidino‐2‐phenylindole dihydrochloride) staining, reactive oxygen species generation and mitochondrial membrane potential determination. Results confirmed the AgNPs synthesised using T. cordifolia leaves are found to be highly toxic against human lung adenocarcinoma cell line A549.Inspec keywords: toxicology, cellular biophysics, cancer, silver, biomembranes, drugs, nanofabrication, nanoparticles, transmission electron microscopy, drug delivery systems, nanomedicine, lung, biomedical materials, antibacterial activity, X‐ray diffraction, Fourier transform infrared spectra, scanning‐transmission electron microscopyOther keywords: cytotoxicity, phytosynthesised silver nanoparticles, A549 cell line, biosynthesis, aqueous leaf, transmission electron microscopy, TEM, X‐ray analysis, X‐ray diffraction, spherical morphology, human lung adenocarcinoma cell line, nuclear morphological changes, 4, 6‐diamidino‐2‐phenylindole dihydrochloride, Tinospora cordifolia leaves, scanning electron microscopy, Fourier transform infrared, energy dispersive X‐ray analysis, Ag, size 25.0 nm to 50.0 nm, anticancer efficiency, trypan blue assay, propidium iodide, Annexin V‐FITC, DAPI staining, reactive oxygen species generation, mitochondrial membrane potential determination     

Investigation of flow around a pair of side-by-side square cylinders using the lattice Boltzmann method

The low-Reynolds number flow around two square cylinders placed side-by-side is investigated using the lattice Boltzmann method (LBM). The effects of the gap ratio s/d (s is the separation between the cylinders and d is the characteristic dimension) on the flow are studied. These simulations reveal the existence of regimes with either synchronized or non-synchronized vortex-shedding, with transition occurring at s/d ≈ 2, which is larger than for circular cylinders. Detailed results are presented at Re = 73 for s/d = 2.5 and 0.7 corresponding to the synchronized and flip-flop regimes, respectively. Vortex-shedding from the cylinder occurs either in-phase or in-antiphase in the synchronized regime. However, linear stochastic estimate (LSE) calculations show that in-phase locking is the predominant mode. LSE is also employed to educe the underlying modes in the flip-flop regime, where evidence for both in-phase and anti-phase locked vortices is found, indicating that this regime is in a quasi-stable state between these two modes. The merging of the wakes, which is gradual for the synchronized regime, occurs rapidly in the flip-flop regime. The mean pressure on the upstream surface is symmetric and asymmetric for the synchronized and flip-flop regimes, respectively. Differences in results between the two regimes are interpreted in terms of the interaction of the jet formed between the cylinders with the adjoining wakes, the strength of this interaction depending on the spacing.     

The synthesis and characterization of novel coumarin dyes derived from 1,4-diethyl-1,2,3,4-tetrahydro-7-hydroxyquinoxalin-6-carboxaldehyde

1,4-Diethyl-1,2,3,4-tetrahydro-7-hydroxyquinoxalin-6-carboxaldehyde was synthesized and condensed with substituted active methylene compounds to obtain a series of novel coumarin compounds. Solutions of the dyes in various solvents exhibited an orange hue and brilliant fluorescence and displayed high thermal stability, as determined using thermogravimetric analysis. The dye having a heterocyclic benzimidazole ring as an electron withdrawing system was selected as a representative compound for comparison of its spectral characteristics with known analogues.     

On the elastic stability of simply supported anisotropic sandwich panels

Here, the elastic stability behavior of simply supported anisotropic sandwich flat panels subjected to mechanical in-plane loads is investigated using an analytical approach. The formulation is based on first-order shear deformation theory and the shear correction factors employed are based on energy consideration that depends on the lay-up as well as material properties. The governing equations are obtained using the Raleigh–Ritz method assuming a combination of sine and cosine functions in the form of double Fourier series for the displacement fields. The effectiveness of the integrated formulation is tested for global characteristics considering examples related to multi-layered laminates and sandwich panels for which solutions are available.     

Modeling of heterogeneous catalysts using simple geometry supports

The application of a novel model catalyst is demonstrated in this work. In this catalyst, oxide particles of simple geometric shape are used as a catalyst support. The simple geometry facilitates observations of the dispersed phase by transmission electron microscopy. We present our results on the effect of support and pretreatment on metal particle morphology and reactivity. This revised version was published online in June 2006 with corrections to the Cover Date.     

Recent studies of thin films and surfaces by high-Resolution electron microscopy

The technique of high-resolution electron microscopy represents a powerful method for characterizing the microstructure of thin films and surfaces. We demonstrate its usefulness by reference to some recent studies of metals, semiconductors, and oxides, in particular, showing that it can be used to follow physical and chemical changes inducedin situ by the electron beam orex situ as a result of annealing or chemical treatment. This invited critical overview paper is based on a presentation made in the symposium “Structure and Properties of Fine and Ultrafine Particles, Surfaces and Interfaces” presented as part of the 1989 Fall Meeting of TMS, October 1–5, 1989, in Indianapolis, IN, under the auspices of the Structures Committee of ASM/MSD.     

Joint Hypothesis Tests for a Unit Root When There is a Break in the Innovation Variance

Abstract. We develop extensions of the Dickey–Fuller F‐statistics for the joint null hypothesis of a unit root that allows for a break in the innovation variance. Our statistics are based on the modified generalized least squares (GLS) strategy outlined in Kim, Leybourne and Newbold [Journal of Econometrics (2002) Vol. 109, pp. 365–387] that requires estimation of the break‐date and corresponding pre‐break and post‐break variances. We derive the asymptotic distribution of the new F‐statistics, tabulate their finite sample and asymptotic critical values, and present finite sample simulation evidence regarding their size and power.     

On-line acquisition of link deformation for the robot of accuracy

No manipulator is rigid. The actual end-effector position deviates from the desired one. For the remedy, compensation methods have been investigated. This paper presents the on-line acquisition method of link deflection and bending angle necessary for compensation methods.