Wrapping the walls of n-TiO2 nanotubes with p-CuInS2 nanoparticles using pulsed-electrodeposition for improved heterojunction photoelectrodes

The CuInS(2) (CIS) nanoparticles were wrapped uniformly throughout the inner and outer walls of TNTs (TNT) by using square wave pulsed-electrodeposition. This structure enables the CuInS(2)-TiO(2) (CIS-TNT) to exhibit p-n junction diode behavior and enhanced photoelectrochemical properties.     

Casbane diterpene as a promising natural antimicrobial agent against biofilm-associated infections

Croton nepetaefolius is a native plant from northeastern Brazil that belongs to the Euphorbiaceae family. The biological action of this plant has been extensively explored, being the secondary metabolites responsible for its properties alkaloids, diterpenes, and triterpenes. This study aimed to evaluate the ability of casbane diterpene (CD), isolated from the ethanolic extract of C. nepetaefolius, to inhibit microbial growth and biofilm formation of several clinical relevant species (bacteria and yeasts). It was found that CD possessed biocidal and biostatic activity against the majority of the species screened, with minimal active concentrations ranging between 125 and 500 μg/mL. In addition, it was observed that biofilm formation was inhibited even when the planktonic growth was not significantly affected. In conclusion, CD showed potential to be a natural tool for the treatment of diseases caused by different infectious microorganisms.     

Synthesis of Ge-imogolite: influence of the hydrolysis ratio on the structure of the nanotubes

The synthesis protocol for Ge-imogolite (aluminogermanate nanotubes) consists of 3 main steps: base hydrolysis of a solution of aluminum and germanium monomers, stabilization of the suspension and heating at 95 °C. The successful synthesis of these nanotubes was found to be sensitive to the hydrolysis step. The impact of the hydrolysis ratio (from n(OH)/n(Al) = 0.5 to 3) on the final product structure was examined using a combination of characterization tools. Thus, key hydrolysis ratios were identified: n(OH)/n(Al) = 1.5 for the formation of nanotubes with structural defects, n(OH)/n(Al) = 2 for the synthesis of a well crystallized Ge imogolite and n(OH)/n(Al) > 2.5 where nanotube formation is hindered. The capability of controlling the degree of the nanotube's crystallinity opens up interesting opportunities in regard to new potential applications.     

Visible light-induced charge storage, on-demand release and self-photorechargeability of WO3 film

Tungsten oxide (WO(3)) electrodes subjected to a positive bias are self-photorecharged with alkali cations in the electrolyte during visible light illumination. Upon photoexcitation, part of the photogenerated charges generated by WO(3) is stabilized by the cations and stored in situ within the WO(3) framework. This light-induced storage of charges is subsequently utilized in dark conditions in an on-demand manner and is able to be recharged in the successive illumination cycles. The amount of charges stored is shown to be dependent on the cation ionic radii and the presence of these intercalated cations is verified by X-ray diffraction (XRD) and inductively coupled plasma mass spectroscopy (ICP-MS). This self-photorecharge and on-demand charge-release phenomena demonstrate the ability of WO(3) to supply photoexcited charges under dark condition in a photoelectrochemical reaction with greater flexibility.     

The effect of unresolved transition arrays on plasma opacity calculations

Unresolved transition arrays (UTAs) are a method of approximating complex atomic physics in plasma opacity calculations, and as such are very important in modern plasma dynamic simulations. In this paper we use full atomic physics calculations to test various UTA models, paying particular attention to the lineshape and its effect on the mean opacity. We find that a Gaussian lineshape is sufficient provided that the line width is correctly determined. This width can be calculated using existing formulae, or approximated by neglecting correlations between term line energies and strengths or the selection rules on term - term transitions. We have quantified transition array narrowing due to correlations for a set of iron transitions and shown that a simple model for these incurs fairly large random errors. The neglect of the selection rules is also seen to result in random errors of up to an order of magnitude. These results may prove very useful in the future development of opacity codes, in particular those intended to run in line with hydrodynamic simulations.     

Weakly Closed Functions and Hausdorff Spaces

For weakly closed surjections between arbitrary topological spaces conditions are sought which assure a HAUSDORFF range. Some results of T. NOIRI are corrected and/or improved, and some results of J. K. KOHLI are slightly strengthened.     

Cessation of Aggregate Growth

Various methods are available for reducing or ceasing growth of aggregating suspensions including the addition of highly charged adsorbents (such as gelatin), reduction of ionic strength by dilution, increase in surface charge by alteration in pH and reduction in suspension temperature. The effectiveness of each of these methods in stopping the aggregation of colloidalhematite without altering the aggregate size distribution is examined in this study. Reduction in aggregate temperature is found to be a particularly effective way of stopping the aggregation of hematite while preserving size distribution information.