Morphology of sealant/enamel interface after surface treatment with bioactive glass

The purpose of this study was to analyze, by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM), the morphology of sealant/enamel interface after surface treatment with Biosilicate. Before pits and fissures sealing, the occlusal surfaces of 10 sound human molars were sectioned perpendicularly at the fissures in order to obtain three slices for each tooth. Slices were randomly assigned into three groups (n = 10) according to sealing protocol: Group 1‐ Acid etching + Biosilicate + glass ionomer‐based sealant (Clinpro XT Varnish, 3M ESPE); Group 2‐ Acid etching + glass ionomer‐based sealant (Clinpro XT Varnish, 3M ESPE); Group 3‐ No sealing. All slices were subjected to thermal cycling (5,000 cycles; 5–55°C; dwell time: 30s). Half of the slices from each group (n = 5) were analyzed by CLSM and the other half by SEM. Groups 1 and 2 were also submitted to EDS analysis and their data were evaluated by Two‐Way ANOVA e Tukey's test (α=5%). EDS data analysis showed higher amounts of silicon (Si) ions than calcium (Ca) ions in Group 1 (P < 0.05); Group 2 presented higher amounts (P < 0.05) of Ca ions than Si ions. It may be concluded that the use of Biosilicate for surface treatment did not affect the morphology of glass ionomer‐based sealant/enamel interfaces. Microsc. Res. Tech. 78:1062–1068, 2015. © 2015 Wiley Periodicals, Inc.     

Seasonal variations of chemical composition in prickly pear (Opuntia ficus-indica (L.) miller)

The moisture, ash, free reducing sugar, starch, ether extractive, crude protein, amino acid and the heat energy contents of young and mature cladodes of Opuntia ficus-indica, with or without fruits, are described. The measurements were made in each of the following stages of development: vegetative growth (March), full vegetative development, and at the beginning of fructification (October). Independently of developmental stage (different cladode types) the highest values were reached always in young cladodes in the following months: moisture content in March and October; ash and free reducing sugars in March; starch and ether extractive in September and October; crude protein in March and July. Crude fibre was maximal in September and global heat energy in October. The nutritive and caloric value of cladodes are compared to other products used for livestock nutrition.     

Production of Nanoparticles in Thermal Plasmas: A Model Including Evaporation,Nucleation, Condensation,and Fractal Aggregation

In this work a coupled model for the production of nanoparticles in an inductively coupled plasma reactor is proposed. A Lagrangian approach is used to describe the evaporation of precursor particles and an Eulerian model accounting for particle nucleation, condensation, and fractal aggregation. The models of the precursor and nanoparticles are coupled with the magneto-hydrodynamic equations describing the plasma. The purpose of this study is to develop a model for the synthesis of particles in a thermal plasma reactor, which can be used to optimize industrial reactors. The growth of aggregates is considered by introducing a power law exponent D _f. Results are compared qualitatively and quantitatively with existing experimental data from plasma reactors at a relatively large laboratory scale. The results obtained from the model confirm the previously observed importance of the quench strategy in defining the morphology of the nanoparticles.     

Galerkin and Least Squares Methods to Solve a 3D Convection–Diffusion–Reaction Equation with Variable Coefficients

This study addresses how to implement the Galerkin finite element and least square finite element methods using auxiliary equations to solve the partial differential equation numerically, which models the convection–diffusion–reaction, set on a steady 3D domain. In the spatial discretization, hexahedral elements with eight (linear element) and 27 (quadratic element) nodes were used, in which Lagrange interpolation functions were adopted in local coordinates. Turning all the formulation of the problem of global coordinates into local coordinates, the Gauss–Legendre quadrature method was used to integrate coefficients of the element matrices numerically. In addition to the formulation by the two methods, a computer code was implemented to simulate the phenomenon proposed. By using analytical solutions, sundry numerical error analysis was performed from L₂ norm (domain–average error) and L_∞ norm (domain–top error), thus validating the numerical results. A real case is proposed and assessed.     

Long-Chain-Amine Metal Complexes as Hydrogenation Catalysts. Heterogenisation on Activated Carbon

The catalytic activity of [PdCl₂(NH₂(CH₂)₁₂CH₃)₂] (named [Pd(TDA)]) and [RhCl(NH₂(CH₂)₁₂CH₃)₃] (named [Rh(TDA)]) complexes for the hydrogenation of cyclohexene has been analysed both in homogeneous phase and heterogenised on activated carbon. The [Rh(TDA)] complex has been found to be more active than the [Pd(TDA)], both homogeneous and heterogenised. Experimental and modelled results indicate that these complexes follow a similar reaction mechanism, but with different rates. A clear positive effect of the carbon support has been found in the case of the complex [Rh(TDA)], which has been related to the anchorage of the aliphatic chains of the amine ligands on the activated carbon pores. Experiments in consecutive catalytic runs show that the heterogenised complexes can be used several times giving an acceptable conversion level.     

Book reviews

Shelter Is Not Enough: Transforming Multi-Storey Housing. Graham Towers. Policy, Bristol, 2000. ISBN 1861341563. 259 pp. RRP £19.99.

Social Policy in Aotearoa New Zealand: A Critical Introduction. Christine Cheyne, Mike O'Brien and Michael Belgrave. Oxford University Press, Auckland, 2000. ISBN 0195584422 (paperback). 275 pp.; bibliography and index. RRP NZ$37.95, A$28.95.

Citizenship and Migration: Globalization and the Politics of Belonging. Stephen Castles and Alastair Davidson. Macmillan, London, 2000. ISBN 0333643100. vii + 258 pp.; RRP $47.00.

Queer City: Gay and Lesbian Politics in Sydney. Craig Johnston and Paul van Reyk (eds). Pluto, Sydney, 2001. ISBN 1864031921. 322 pp. RRP $32.95.

Environmental Planning and Management in New Zealand. P. Ali Memon and Harvey C. Perkins (eds). Dunmore, Palmerston North, rev. edn, 2000. ISBN 086469363X (paperback). 401 pp.; bibliography and index. RRP NZ$66.00.

Resetting the Compass: Australia's Journey Towards Sustainability. David Yencken and Debra Wilkinson. CSIRO Publishing, Melbourne, 2000. ISBN 0643063854 (paperback). 416 pp.; endnotes and index. RRP $39.95.     

Photocatalytic production of hydrogen from electrodeposited film and sacrificial electron donors

A new approach to combining a p-type semiconductor photocathode with sacrificial electron donors in the anode compartment in a two-compartment cell is described for photocatalytic hydrogen production. This approach is demonstrated for electrodeposited p-Cu₂O film supported on a transparent conducting oxide substrate. The oxide semiconductor surface was photochemically modified in situ with an ultra-thin Ni layer prior to use. A variety of organic and organometallic electron donors was screened by cyclic voltammetry, and the optimal candidate was hydroquinone at pH 10. Importantly, no photocurrents were measured at zero bias voltage in the two-compartment cell in the absence of an electron donor, signaling that water photosplitting is not feasible with p-Cu₂O. Methyl viologen (MV²⁺) was effective as an electron relay in the photocathode chamber as shown by in situ spectroscopic monitoring of the MV⁺ radical cations. Finally, practical perspectives of this new approach and value-added options for combining it with pollutant destruction are described.