Chemical compositions of essential oils from two Artemisia species used in Mongolian traditional medicine

Essential oils of aromatic and medicinal plants generally have a diverse range of activities because they possess many active constituents that work through a several modes of action. Artemisia, the largest genus of the family Asteraceae, has a number of effects against human and plant diseases. The main purpose of the present study was to investigate chemical compositions of essential oils of two Artemisia species, Artemisia palustris L and Artemisia sericea Weber ex Stechm from the Mongolian steppe zone using gas chromatography and gas chromatography-mass spectrometry. The essential oil of A.palustris was characterized by the presence of monoterpene hydrocarbons such as  trans-β-ocimene (59.1%), cis-β-ocimene (11.6%) and myrcene (7.1%), while the oil of A.sericea was dominated by the presence of three oxygenated monoterpenoids as 1,8-cineole (25.8%), borneol (22.5%) and camphor (18.8%) which are used for preparation of a fragrance and medicinal products

Simple fabrication of Ag nanoparticle-impregnated electrospun nanofibres as SERS substrates

© Indian Academy of Sciences. A facile method for the fabrication of electrospun polyurethane (PU) nanofibres impregnated with Ag nanoparticles (NPs) as an efficient and free-standing surface-enhanced Raman scattering (SERS) substrates is reported here. Electrospinning was used to produce polymeric nanofibrous matrix, while a liquid polyol(ethylene glycol) solvent under low temperature was used not only to reduce Ag+ to Ag0, but also was employed as the in situ growth medium for well-dispersed Ag NPs on the surface of fibre nets. Large enhancement in Raman signals of 4-mercaptobenzoic acid analytes could be realized in the present Ag/PU nanofibres due to the presence of SERS 'hotspots' by means of appropriate interparticle gap

Effect of annealing on the phase transition and morphology of Ag NPs on/in TiO <inf>2</inf> rods synthesized by a polyol method

In this study, we report the effect of annealing (250-700 oC) on the phase transition and morphology of silver (Ag) nanoparticles (NPs) on/in titanium dioxide (TiO 2) rods prepared using a polyol method. The annealed samples showed not only morphological change, i.e.; a solid-to-liquid (melting) transition of Ag NPs due to its partial dissolution into the TiO 2 rods, but also early stage anatase crystallization and anatase-rutile transformation of TiO 2 rods under low annealing temperatures. Such findings, together with XRD and FE-SEM analyses, confirm that, upon higher annealing treatment, diffusion and coalescence leads to changes in the size and shape of the metal particles not only in the outermost regions, but also a random distribution and progressive growth of Ag clusters in the inner interface region. Here, it was shown that annealing can induce changes in morphology, as well as the chemical state and structure of Ag-TiO 2. The present polyol-synthesized Ag-TiO 2 composite also showed improved thermal stability. © 2012 Elsevier Ltd and Techna Group S.r.l

One-pot synthesis of silver-titanium dioxide nanocomposites using ethylene glycol medium and their antibacterial properties

We report here for the first time a one-pot simultaneous synthesis and antibacterial properties of Ag-TiO 2 nanocomposites via ethylene glycol medium. The salient features of this method include simple operation, large scale production and one medium (solvent) to produce two different nanoparticles. Clusters of Ag and TiO 2 nanoparticles with an average size of 20 - 30 nm and narrow size distribution are formed after annealing at 400 and 500 oC. The annealed Ag-TiO 2 nanoparticles show excellent antibacterial properties under visible-light irradiation

Simultaneous preparation of Ag/Fe<inf>3</inf>O<inf>4</inf> core-shell nanocomposites with enhanced magnetic moment and strong antibacterial and catalytic properties

In this study, core-shell Ag/Fe3O4 nanocomposites have been successfully prepared by modified co-precipitation route followed by facile hydrothermal treatment in one-pot synthesis under various (Ag(NH3)2+) ion concentrations without adding any reducing agents. A single crystal Ag core and polycrystallized Fe3O4 shell nanostructures could be obtained when high amount of AgNO3 precursor are used in the presence of Fe2+ ions source, i.e., ferrous salt alone. A mechanism leading to the formation of such morphologies was proposed and samples were characterized with several analytical techniques including field emission scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared (FT-IR) spectroscopy. Significant increase of saturation magnetic moment was observed for the Ag/Fe3O4 nanocomposite. The results showed enhanced magnetic moment and strong catalytic and antibacterial activities of the present Ag/Fe3O4 nanocomposite, demonstrating its importance for potential application in water treatment and biomedical application, with the ability of subsequent removal by means of an external magnetic field. © 2013 Elsevier B.V

Controlled assembly of superparamagnetic iron oxide nanoparticles on electrospun PU nanofibrous membrane: A novel heat-generating substrate for magnetic hyperthermia application

A facile method of fabricating novel heat-generating membranes composed of electrospun polyurethane (PU) nanofibers decorated with superparamagnetic iron oxide nanoparticles (NPs) is reported. Electrospinning was used to produce polymeric nanofibrous matrix, whereas polyol immersion technique allowed in situ assembly of well-dispersed Fe3O4 NPs on the nanofibrous membranes without any surfactant, and without sensitizing and stabilizing reagent. The assembly phenomena can be explained by the hydrogen-bonding interactions between the amide groups in the PU matrix and the hydroxyl groups capped on the surface of the Fe3O4 NPs. The prepared nanocomposite fibers showed acceptable magnetization value of 33.12 emu/g, after measuring the magnetic hysteresis loops using SQUID. Moreover, the inductive heating property of electrospun magnetic nanofibrous membranes under an alternating current (AC) magnetic field was investigated. We observed a progressive increase in the heating rate with the increase in the amount of magnetic Fe3O4 NPs in/on the membranes. The present electrospun magnetic nanofibrous membrane may be a potential candidate as a novel heat-generating substrate for localized hyperthermia cancer therapy. © 2013 Elsevier Ltd. All rights reserved

Simultaneous synthesis of TiO <inf>2</inf> microrods in situ decorated with Ag nanoparticles and their bactericidal efficiency

In this study, we report a simple and cost-effective method for in situ decoration of Ag NPs onto nanoporous TiO 2 microrods by one medium (ethylene glycol) that can produce two different morphologies. In order to investigate the morphology, phase composition, crystalline structure, and chemical state (valency) of samples before and after annealing in air at different temperatures, field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) were performed. The present results show that the size, morphology and crystallinity of both Ag NPs and TiO 2 microrod substrate depend on the post-annealing treatment temperatures. The annealed Ag-TiO 2 NP/microrod composites show large inhibition zones against E. coli bacteria. The obtained Ag-TiO 2 composites have the potential for use as a novel antibacterial material and in water treatment applications. © 2011 Elsevier B.V. All rights reserved