Health benefits of CLA – lessons from pig models in biomedical research

The objective of this review is to highlight the use of pig models for investigating safety, efficacy and the mechanisms of action of conjugated linoleic acid (CLA). Although CLA elicits positive effects in animal models and in vitro systems, a consistent concern in terms of translational research is that the health benefits observed by using these model systems cannot be extrapolated directly into humans. Conversely, the similarities between pigs and humans make the pig an ideal model for examining the health benefits of dietary supplements, functional foods and nutraceuticals. We have developed pig models of viral and bacterial infection to examine the preventive role of dietary CLA supplementation on virally induced immunosuppression and gut health, respectively. Results from these studies indicate that CLA significantly enhances the immune function while limiting the catabolic effects of uncontrolled immune and inflammatory responses. The scientific findings in pig models and human clinical trials demonstrate that CLA modulates immune responses in pigs and humans. Pig models of immunomodulation represent significant improvements over other animal models and in vitro systems because they mimic more closely the compartmentalization of the human immune system and the clinical presentation of human infectious, immune and inflammatory diseases.     

The production of a lead glaze with galena: Thermal transformations in the PbS–SiO2 system

Galena, also known as PbS, was widely used in the production of lead glazes from the beginning of the 18th century to the second half of the 20th century. Although the PbO‐SiO₂ system has been studied for years, the PbS–SiO₂ phase diagram, involved in the formation of a glaze with galena, has not yet been investigated. Temperature transformations for the system 75 wt% PbS‐25 wt% SiO₂ are investigated in a high‐temperature resolved X‐ray diffraction experiment with synchrotron radiation and compared to those of the equivalent system 70 wt% PbO‐30 wt% SiO₂. Lanarkite, PbO·PbSO₄, is the phase predominantly formed as soon as galena decomposes during the heating. The results show that the system melts at a temperature higher than the PbO–SiO₂ system, but far lower than those expected for the PbO–PbSO₄–PbS system. A historical misfired lead glaze produced with galena is also studied. The presence of galena, lanarkite, and mattheddleite, Pb₁₀(SiO₄)_3.5(SO₄)₂Cl_2, is determined and discussed in terms of the composition of the galena mineral used and the firing conditions in light of the high‐temperature transformations previously obtained.     

pH-responsive drug delivery system based on hollow silicon dioxide micropillars coated with polyelectrolyte multilayers

We report on the fabrication of polyelectrolyte multilayer-coated hollow silicon dioxide micropillars as pH-responsive drug delivery systems. Silicon dioxide micropillars are based on macroporous silicon formed by electrochemical etching. Due to their hollow core capable of being loaded with chemically active agents, silicon dioxide micropillars provide additional function such as drug delivery system. The polyelectrolyte multilayer was assembled by the layer-by-layer technique based on the alternative deposition of cationic and anionic polyelectrolytes. The polyelectrolyte pair poly(allylamine hydrochloride) and sodium poly(styrene sulfonate) exhibited pH-responsive properties for the loading and release of a positively charged drug doxorubicin. The drug release rate was observed to be higher at pH 5.2 compared to that at pH 7.4. Furthermore, we assessed the effect of the number of polyelectrolyte bilayers on the drug release loading and release rate. Thus, this hybrid composite could be potentially applicable as a pH-controlled system for localized drug release.     

The interpretation of X-ray photoelectron spectra of pyrolized S-containing carbonaceous materials

Theoretical models and ab initio Hartree-Fock wavefunctions have been used to investigate the S(2p) core level binding energies (BE), of pyrolized S-containing, carbonaceous materials. Comparison between experimental and calculated data for thiophene permits the accuracy of the present approach to be established. A systematic study of different situations demonstrates that, in these materials, non-oxidized S atoms can show peaks at very high BE relative to the C(1s) peak at 285.0 eV. This study confirms that the peak at 164.1 eV corresponds to ‘thiophenic’ S atoms. On the other hand, it shows that the peaks at higher BE could correspond to S atoms replacing C atoms in three-coordinated structures of graphene layers, in agreement with the arguments suggested in the experimental works. The energetic similarity between the two peaks at very high BE makes it difficult to differentiate between them, although the results of the present study seem to suggest that the peak at experimental BE ≈ 166 eV could correspond to S atoms coordinated to two C and one H atoms at the edge of graphene layers, while the peak at ≈ 169 eV would correspond to S atoms replacing C atoms in inner positions of the graphene layers, and it is bonded to three C atoms.     

Effect of pre‐treatments based on UV photocatalysis and photo‐oxidation on toluene biofiltration performance

BACKGROUND: The integration of UV photocatalysis and biofiltration seems to be a promising combination of technologies for the removal of hydrophobic and poorly biodegradable air pollutants. The influence of pre‐treatments based on UV_{254 nm} photocatalysis and photo‐oxidation on the biofiltration of toluene as a target compound was evaluated in a controlled long‐term experimental study using different system configurations: a standalone biofilter, a combined UV photocatalytic reactor‐biofilter, and a combined UV photo‐oxidation reactor (without catalyst)‐biofilter. RESULTS: Under the operational conditions used (residence time of 2.7 s and toluene concentrations 600–1200 mg C m^?3), relatively low removal efficiencies (6–3%) were reached in the photocatalytic reactor and no degradation of toluene was found when the photo‐oxidation reactor was operated without catalyst. A noticeable improvement in the performance of the biofilter combined with a photocatalytic reactor was observed, and the elimination capacity of the biological process increased by more than 12 g C h^?1 m^?3 at the inlet loads studied of 50–100 g C h^?1 m^?3. No positive effect on toluene removal was observed for the combination of UV photoreactor and biofilter. CONCLUSIONS: Biofilter pre‐treatment based on UV_{254 nm} photocatalysis showed promising results for the removal of hydrophobic and recalcitrant air pollutants, providing synergistic improvement in the removal of toluene. Copyright © 2011 Society of Chemical Industry     

Electrical and mechanical characterization by instrumented indentation technique of La0.85Sr0.15Ga0.8Mg0.2O3−δ electrolyte for SOFCs

La_0.85Sr_0.15Ga_0.8Mg_0.2O_3?δ pellets obtained by the polymeric organic complex solution method, isostatic pressing and sintering at 1350 °C have been electrical and mechanically studied. Electrical measurements evidenced reasonable ionic conductivities (0.01 S cm^?1 at 800 °C), which were comparable to those reported for the La_1?xSr_xGa_1?yMg_yO_3?δ prepared by other synthesis methods. On the other hand, the mechanical properties (elastic modulus, E and hardness, H) have been determined at micro/nanometric scale using the instrumented indentation technique. While E did not vary significantly with the increasing indentation depth (h), H values strongly decreased with the indentation depth up to 500 nm. For h > 500 nm, both mechanical properties remained almost constant, thus obtaining E = 271 ± 6 GPa and H = 13.2 ± 0.4 GPa. Finally, the residual imprints and fracture mechanisms have been observed by atomic force microscopy (AFM).     

Testing for Panel Cointegration Using Common Correlated Effects Estimators

Spurious regression analysis in panel data when the time series are cross section dependent is analysed in the article. We show that consistent estimation of the long‐run average parameter is possible once we control for cross section dependence using cross section averages in the spirit of the common correlated effects approach proposed by Pesaran. This result is used to design a panel cointegration test statistic accounting for cross section dependence. The performance of the proposal is investigated in comparison with factor‐based methods to control for cross section dependence when strong, semi‐weak and weak cross section dependence may be present.     

New thermosets obtained by copolymerization of DGEBA with 1,5,7,11-tetraoxaspiro[5,5]undecane catalyzed by lanthanide triflates

DGEBA epoxy resin was cured with different proportions of 1,5,7,11-tetraoxaspiro[5,5]undecane (TOSU) with ytterbium and lanthanum triflates as catalysts. The curing was studied by differential scanning calorimetry (DSC) and Fourier transform infrared in the attenuated-total-reflexion mode (FTIR/ATR).FITR/ATR was used to monitor the competitive reactive processes and to quantify the evolution of the epoxide, orthocarbonate, linear carbonate and other groups formed in the curing process. The T_g of the cured materials decreased when the proportion of TOSU increased. The kinetics were studied by DSC experiments and analyzed with iso-conversional procedures. The systems catalyzed by ytterbium triflate had a higher curing rate and reached a higher degree of cross-linking. The addition of TOSU reduced the degree of overall shrinkage and even led to one material expanding. The flexibility and the degradability of these materials were improved by introducing higher proportions of TOSU.