Different biological methods are gaining recognition for the production of silver nanoparticles (Ag-NPs) due to their multiple applications. The use of plants in the green synthesis of nanoparticles emerges as a cost effective and eco-friendly approach. In this study the green biosynthesis of silver nanoparticles using Callicarpa maingayi stem bark extract has been reported. Characterizations of nanoparticles were done using different methods, which include; ultraviolet-visible spectroscopy (UV-Vis), powder X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray fluorescence (EDXF) spectrometry, zeta potential measurements and Fourier transform infrared (FT-IR) spectroscopy. UV-visible spectrum of the aqueous medium containing silver nanoparticles showed absorption peak at around 456 nm. The TEM study showed that mean diameter and standard deviation for the formation of silver nanoparticles were 12.40 ± 3.27 nm. The XRD study showed that the particles are crystalline in nature, with a face centered cubic (fcc) structure. The most needed outcome of this work will be the development of value added products from Callicarpa maingayi for biomedical and nanotechnology based industries.

A MgB 2 microparticles modified glassy carbon electrode (MgB 2 /GCE) was fabricated by adhering microparticles of MgB 2 onto the electrode surface of GCE. It was used as a working electrode for the detection of paracetamol in 0.1 M KH 2 PO 4 aqueous solution during cyclic voltammetry. Use of the MgB 2 /GCE the oxidation process of paracetamol with a current enhancement significantly by about 2.1 times. The detection limit of this modified electrode was found to be 30 µM. The sensitivity under conditions of cyclic voltammetry is significantly dependent on pH, supporting electrolyte, temperature and scan rate. The current enhancement observed in different electrolytic media varied in the following order: KH 2 PO 4 > KCl > K 2 SO 4 > KBr. Interestingly, the oxidation of paracetamol using modified GC electrode remain constant even after 15 cycling. It is therefore evident that the MgB 2 modified GC electrode possesses some degree of stability. A slope of 0.52 dependent of scan rate on current indicates that the system undergoes diffusion-controlled process.

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We report the results of a laser-molecular beam scattering study of liquid surfaces. I, is used as a probe molecule and its internal quantum-state distribution is determined both before and after scattering from the surface of liquid samples. Time resolution of the laser-induced fluorescence signal allows us to distinguish the processes of direct inelastic scatter and trapping followed by desorption. Marked differences in the spectral patterns, are observed as laser timing is varied and also when the liquid sample is changed. The effect of the chemical nature of the surface is particularly marked in gallium for which reactive channels are likely. An analysis of surface-dependent trapping and desorption is presented based on the availability of acceptor and promoter modes of molecules in the liquid surface. Modes associated with the CH, group appear to be particulary efficient in absorbing the translational energy of small gas-phase molecules whilst those of the CF, group are less effective. Polydimethylsiloxane has a range of acceptor modes and hence is an efficient trap species. Furthermore it possesses effective promoter modes and torsional motions of the Si-0-Si link may be closely involved in this role.

We report the results of a laser molecular beam scattering study of liquid surfaces. Molecular iodine is used as a probe molecule and its number density and quantum-state distribution is determined before and after scattering from the surface of a liquid by laser-induced fluorescence (LIF). Time resolution of the LIF signal allows us to separate processes of direct inelastic scatter from trapping followed by desorption. Here we focus mainly on the latter process and obtain data on the kinetics of desorption and the activation energy of desorption together with insights into the dynamical processes that lead to trapping and desorption.