Growth of InP nanostructures via reaction of indium droplets with phosphide ions: synthesis of InP quantum rods and InP-TiO2 composites

InP quantum rods were synthesized via the reaction of monodispersed colloidal indium droplets with phosphide ions. In(0) droplets, which do not act as a catalyst but rather a reactant, are completely consumed. The excess electrons that are produced in this reaction are most likely transferred to an oxide layer at the indium surface. For the synthesis of InP quantum rods with a narrow size distribution, a narrow size distribution of In(0) particles is also required because each indium droplet serves as a template to strictly limit the lateral growth of individual InP nanocrystals. Free-standing quantum rods, 60, 120, or 150 A in diameter, with aspect ratios of 1.6-3.5, and without the residual metallic catalyst at the rod tip, were synthesized from the diluted transparent solution of metallic indium particles. The same approach was used to synthesize InAs quantum rods. A photoactive InP-TiO(2) composite was also prepared by the same chemical procedure; InP nanocrystals grow as well-defined spherical or slightly elongated shapes on the TiO(2) surface.     

Antibacterial effect of silver nanoparticles deposited on corona‐treated polyester and polyamide fabrics

The possibility of using a corona treatment (electrical discharge at atmospheric pressure) for fiber surface activation, which can facilitate the loading of silver nanoparticles (NPs) from colloids onto the polyester (PES) and polyamide (PA) fabrics and thus improve their antibacterial properties, was studied. Bactericidal efficiency and its laundering durability on silver‐loaded fabrics for Gram‐positive bacterium Staphylococcus aureus and Gram‐negative bacterium Escherichia coli were evaluated. The fiber morphology after corona treatment and subsequent loading of silver NPs was followed by SEM. Corona‐treated fabrics loaded with silver NPs exhibited better antibacterial properties in comparison with untreated fabrics. In order to obtain acceptable laundering durability, it is necessary to use highly concentrated silver colloids. Copyright © 2008 John Wiley & Sons, Ltd.     

Photoluminescence of anatase and rutile TiO2 particles

Nonaqueous reactions between titanium(IV) chloride and alcohols (benzyl alcohol or n-butanol) were used for the synthesis of anatase TiO2 particles, while rutile TiO2 particles were synthesized in aqueous media by acidic hydrolysis of titanium(IV) chloride. The X-ray diffraction measurements proved the exclusive presence of either the anatase or the rutile phase in prepared samples. The photoluminescence of both kinds of particles (anatase and rutile) with several well-resolved peaks extending in the visible spectral region was observed, and the quantum yield at room temperature was found to be 0.25%. Photon energy up-conversion from colloidal anatase and rutile TiO2 particles was observed at low excitation intensities. The energy of up-converted photoluminescence spans the range of emission of normal photoluminescence. The explanation of photon energy up-conversion involves mid-gap energy levels originating from oxygen vacancies.     

Self-assembly of linear arrays of semiconductor nanoparticles on carbon single-walled nanotubes

Ligand-stabilized nanocrystals (NCs) were strongly bound to the nanotube surfaces by simple van der Waals forces. Linear arrays of CdSe and InP quantum dots were formed by self-assembly using the grooves in bundles of carbon single-walled nanotubes (SWNTs) as a one-dimensional template. A simple geometrical model explains the ordering in terms of the anisotropic properties of the nanotube surface. CdSe quantum rods were also observed to self-organize onto SWNTs with their long axis parallel to the nanotube axis. This approach offers a route to the formation of ordered NC/SWNT architectures that avoids problems associated with surface derivatization.     

Magnetic properties of ErxY1−xF3 solid solutions

The Er_xY_1−xF₃ (x=0.1, 0.2, 0.7, 0.9, 1) solid solutions were synthesized and characterized by X-ray powder diffraction and magnetic measurements. The crystal structure refinements done by the Rietveld profile method show that no significant change of the structure parameters with the erbium concentration occurs. On the basis of DC susceptibility measurements in the 2-300 K range the lowest four crystal field levels have been determined, giving the ground level magnetic moment value of 6.7 μ_B. Results of M(H) studies point to the presence of complex exchange interactions between erbium ions.     

Kinetics of radical polymerization of dimethylphenyl methacrylates

The kinetics of free radical polymerization of all six existing isomeric dimethylphenyl methacrylates were studied in bulk at 60°C, initiated by dilauroyl peroxide, using dilatometry. The different polymerization rates observed, resulting from the different monomer structures, are discussed in terms of steric and other effects, considering also the previous results for tolyl methacrylates. © 1993 John Wiley & Sons, Inc.     

Multifunctional PES fabrics modified with colloidal Ag and TiO2 nanoparticles

This study is aimed to highlight the possibility of engineering the multifunctional textile nanocomposite material based on the polyester (PES) fabric modified with colloidal Ag and TiO₂ nanoparticles (NPs). The effects of concentration of NPs as well as the order of Ag and TiO₂ NPs loading on antimicrobial, UV protective, and photocatalytic properties of PES fabrics were examined. The antimicrobial activity of differently modified PES fabrics was tested against Gram‐negative bacterium Escherichia coli, Gram‐positive bacterium Staphylococcus aureus, and fungus Candida albicans. The concentration of Ag colloid and the order of Ag and TiO₂ NPs loading considerably affected the antimicrobial efficiency of PES fabrics. The fabrics provided maximum UV protection upon surface modification with Ag and TiO₂ NPs. Ag NPs enhanced Ag NPs enhanced the photodegradation activity of TiO₂ NPs and total photodegradation of methylene blue was achieved after 24 hr of UV illumination. Copyright © 2010 John Wiley & Sons, Ltd.     

How to remove barriers to medicines trade in emerging economies: the role of medicines regulatory authority in Serbia

The primary role of European pharmaceutical legislation is to safeguard public health while encouraging the development of the pharmaceutical industry, creation of single market for pharmaceuticals with removed barriers to medicines trade. This article presents some important characteristics of pharmaceutical legislation in Serbia, the potential EU candidate country, and the latest improvements of existing national pharmaceutical legislation. Additional explanation is given for the Serbian negotiations with World Trade Organization and measures taken for the harmonisation with Agreements on Technical barriers to Trade (TBT), especially with Agreement on Trade-Related Intellectual Property Rights. Current status of Serbian pharmaceutical market is described, with the highlight of domestic manufacturers??capacity to comply with European Union requirements. National medicines agency is described in the framework of European medicines quality infrastructure. The role and responsibility of national medicines authority to assure access to quality, safe and efficacious medicines on Serbian market is described. The special emphasis is given to agency’s role in harmonisation process, in terms of removing unnecessary barriers to medicines trade in Serbia.     

Properties of surface dielectric barrier discharge plasma generator for fabrication of nanomaterials

This paper presents surface dielectric barrier discharge plasma generators as an efficient source of low-energy ions. Either positive or negative ions can be extracted from a plasma cloud with an external DC field created by the third electrode. Three different cross-section geometries of DBD generators were analyzed, simulated and fabricated. Currents of ions extracted from the plasma cloud were measured and the results were discussed. It was demonstrated that if the third electrode consists of liquid–gas interface, the presented arrangement can be used as a versatile reactor for nanomaterial synthesis (on the example of the synthesis of silver nanoparticles).     

Modelling the semi-batch vinyl acetate emulsion polymerization in a real-life industrial reactor

A detailed dynamic model of the polymerization reaction of vinyl acetate in a real-life industrial reactor is presented. With the recipe and the operating procedures observed in the factory as inputs, the model predicts with reasonable accuracy the final conversion, the average particle diameter, the solid content and the viscosity. The manual and semi-manual operations, and the decision process followed by the operator, are also modelled in order to replicate closely the process carried out in the factory. The model provides further insight into the reaction kinetics and allows us to make knowledge-based decisions. The model is intended to be used for the optimization of the policy of adding monomer in order to reduce the batch time.