Angioarchitecture of the ventral surface of the tongue from Wistar rats

The goal of this study was to describe the angioarchitecture of the ventral surface of the tongue from Wistar rats using a vascular corrosion casting technique associated with scanning electron microscopy (SEM). Six Wistar rats were used for the vascular casting method with Mercox resin. Following the resin polymerization, the tongue of each animal was dissected and corroded in a 5% sodium hydroxide solution. Once the corrosion and drying of the specimens were completed, the specimens were mounted on aluminum stubs, coated with carbon and gold and analyzed under SEM. The results showed that the ventral surface of the tongue presents simple, even and abundant vasculature constituted by a vascular plexus consisting of a superficial vascular network and by the ranine veins. The superficial vascular network, made up of the ascending and descending branches, presents as a loose network, with little morphological variation between the capillary loops.     

Transfer studies of polystyrene nanoparticles in the ex vivo human placenta perfusion model: key sources of artifacts

Nanotechnology is a rapidly expanding and highly promising new technology with many different fields of application. Consequently, the investigation of engineered nanoparticles in biological systems is steadily increasing. Questions about the safety of such engineered nanoparticles are very important and the most critical subject with regard to the penetration of biological barriers allowing particle distribution throughout the human body. Such translocation studies are technically challenging and many issues have to be considered to obtain meaningful and comparable results. Here we report on the transfer of polystyrene nanoparticles across the human placenta using an ex vivo human placenta perfusion model. We provide an overview of several challenges that can potentially occur in any translocation study in relation to particle size distribution, functionalization and stability of labels. In conclusion, a careful assessment of nanoparticle properties in a physiologically relevant milieu is as challenging and important as the actual study of nanoparticle–cell interactions itself.     

Cost efficient preparation of lead aminoalkoxides directly from lead(II) oxide

The preparation of lead(II) aminoalkoxides has been demonstrated from the direct reaction of aminoalcohols with lead(II) oxide. The denticity of the aminoalcohols determined the facility of the reactions, the rate increasing with the number of hydroxyls. Thus, [Pb(dmae)₂], 1, [Pb(mdea)]_∞, 2, and [Pb(teaH)]₂, 3 (dmaeH = dimethylaminoethanol, mdeaH₂ = N-methyldiethanolamine, and teaH₃ = triethanolamine) have been prepared in high yields and characterized by ¹H and ¹³C NMR. The X-ray crystal structure analyses of 2 and 3 are described.     

Living free radical polymerization using cyclic trifunctional initiator

Free radical polymerization is a very robust route to produce polymers, however, it does not promote a control on the microstructure of the polymer: usually polymers with wide molecular weight distribution and polydispersity (PDI) greater than 1.5 are obtained. Ionic polymerization can be used to produce polymers with low PDI, however, this kind of route needs to be held with a high degree of purity. Living free radical polymerization (LFRP) is a promising technique to produce controlled polymers. In the literature, monofunctional conventional initiators have been used in LFRP process. In this study, the use of a cyclic trifunctional peroxide on controlled nitroxide mediated radical polymerization was investigated. The initiator used was Trigonox 301 (3,6,9‐triethyl‐3,6,9‐trimethyl‐1,4,7‐triperoxonane—41% solution in isoparaffinic hydrocarbons) and TEMPO (2,2,6,6‐tetramethyl‐1‐piperidin‐1‐oxyl) was used as controller agent. The results obtained show that it is possible to produce controlled polymers at certain operating conditions, when Trigonox 301 is used. It could be observed that the concentration of initiator and the ratio [TEMPO]/[Trigonox 301] have a huge effect on the polymer properties. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

In situ synthesis,morphology, and thermal properties of polystyrene—MgAl layered double hydroxide nanocomposites

Polystyrene (PS)/layered double hydroxide (LDH) nanocomposites were synthesized by in situ free radical bulk polymerization. LDH formed by magnesium and aluminum (Mg:Al—molar ratio of 2:1) was prepared by coprecipitation method and intercalated with sodium dodecyl sulfate (DDS). The nanocomposites were characterized by X‐ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and flammability test. The XRD and TEM demonstrated that synthesized nanocomposites in all compositions studied showed a high global dispersion of LDH in PS, suggesting exfoliation. The results of TGAs (when 50% mass loss was selected as a comparison point) and flammability tests for synthesized nanocomposites, presented a significant improvement in thermal stability and flammability property when compared with pure PS. This behavior and properties indicate application of the surfactant intercalated LDH reinforced PS in fields where thermal stability is an important characteristic. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers     

Improvement on direct ethanol fuel cell performance by using doped-Nafion 117 membranes with Pt and Pt–Ru nanoparticles

Nafion^® 117 membranes doped with Pt (4 × 10⁻⁴ mol L⁻¹ or 8 × 10⁻⁴ mol L⁻¹ H₂PtCl₆ solution), and with Pt–Ru (4 × 10⁻⁴ mol L⁻¹ H₂PtCl₆ and 2 × 10⁻⁴ mol L⁻¹ RuCl₃ solutions) nanoparticles have been synthesized using a simple and scalable absorption-reduction method. The chemical integrity of the membranes was confirmed by ¹³C and ¹⁹F solid-state NMR. The pore microstructure of the membranes was preserved after the doping process, according to SAXS measurements. The tests of the direct ethanol fuel cells (DEFC) performance at 90 °C exhibited up to 38% and 56% increase at the maximum power densities for Pt doped-Nafion^® membrane from lower and higher concentration of H₂PtCl₆ solution, respectively, compared to bare Nafion^® membranes. Additionally, a Pt–Ru doped-membrane tested at 110 °C exhibited the highest power density. Such superior performances may be attributed to a synergistic effect between the extra amount of active catalytic sites inside the pore structure for the electrochemical oxidation of ethanol, thus preventing ethanol crossover, and the excellent proton migration properties conferred by the pore microstructure of Nafion^®. These results demonstrate that the doped-Nafion^® membrane has a good capacity to improve the performance of DEFC, and provided further clarification on the synthesis process of polymer electrolyte doped-membranes in fuel cell technology.     

Effect of the addition of inert or TEMPO‐capped prepolymer on polymerization rate and molecular weight development in the nitroxide‐mediated radical polymerization of styrene

The importance of diffusion‐controlled (DC) effects on controlled radical polymerization (CRP) processes has been rather controversial and usually considered only if there is some mismatch between experimental data and model predictions of polymerization rate and molecular weight averages. Results from an experimental study designed to create conditions in which DC effects may be present from the outset for the bimolecular nitroxide‐mediated radical polymerization (NMRP) of styrene in the presence of 2,2,6,6‐tetramethyl‐1‐piperidinyloxy (TEMPO) and dibenzoyl peroxide (BPO), are presented herein. The experiments consisted of adding size exclusion chromatography (SEC) polystyrene (PS) standards or nitroxyl‐capped PS (of different molecular weights, in several proportions), to a conventional recipe of bimolecular NMRP of styrene, and studying the effect of their presence on polymerization rate and molecular weight development. A previously developed kinetic model for NMRP of styrene was modified to take into account the presence of prepolymer as an inert “solvent,” or as a monomolecular “controller” of high molecular weight. The effects of DC reactions (propagation, termination, activation, and deactivation of polymer radicals) were modeled using conventional free‐volume theory. Reasonably, good agreement between experimental data and model predictions with either modeling approach was obtained. It was concluded that DC effects are weak in the NMRP of styrene, even in the presence of prepolymer. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis, structure and morphology of poly(dimethylsiloxane) networks filled with in situ generated silica particles

The morphology of silica particles generated in situ in PDMS networks in the presence of two types of catalysts is evaluated by using different techniques including solid-state ²⁹Si MAS NMR, near-infrared spectroscopies and small-angle X-ray scattering. The interactions with the poly(dimethylsiloxane) chains are examined through the swelling properties and thermal characteristics (in particular crystallization process) of the composites. In addition, ¹H NMR is used to investigate the adsorption layer of reduced mobility on the particle surface.     

Construction d'une échelle d'attachement au lieu de travail: Une démarche exploratoire.

The purpose of our article is to present a series of five studies on the development and validation of a workplace attachment scale, namely the "Echelle d'Attachement au Lieu de Travail" (éALT). Based upon the Theory of Place Attachment elaborated by Schumaker & Taylor (1983) and conceiving attachment to the workplace as an affective tie between a person and his/her work environment, this scale is derived from the Neighborhood Attachment Scale (Bonnes & al., 1997). More than 750 men and women working in different professional sectors participated in these studies. Preliminary results showed that the éALT has adequate levels of internal consistency and temporal stability. The construct validity of this unidimensional scale is moreover confirmed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

"Adaptation et validation en langue fran?aise d’une échelle de bien-être spirituel": Correction.

Reports an error in "Adaptation et validation en langue fran?aise d’une échelle de bien-être spirituel" by Lucy Velasco and Liliane Rioux (Canadian Journal of Behavioural Science/Revue canadienne des sciences du comportement, 2009[Apr], Vol 41[2], 102-108). The DOI printed in the article was incorrect. The correct DOI should be as follows: DOI: 10.1037/a0012555. (The following abstract of the original article appeared in record 2009-05252-001.) Spiritual well-being is a dimension of subjective well-being which has enjoyed renewed interest for about 10 years. As far as the authors know, there is no scale in French to assess it. Our research work therefore sets out to adapt and validate in French Spiritual Well-Being Scale (SWBS) by Paloutzian and Ellison, published in 1982. To that end, 368 first- and second-year students took part in three studies. Results confirm the three-dimension structure designed by Scott et al. in 1998, justifying its use with the French population. Yet, the change of items in each dimension, which is currently under discussion, could well display some differences in spiritual well-being between young North American people and young French people. (PsycINFO Database Record (c) 2010 APA, all rights reserved)