Dye‐Doped Polyhedral Oligomeric Silsesquioxane (POSS)‐Modified Polymeric Matrices for Highly Efficient and Photostable Solid‐State Lasers

Here, the design, synthesis, and characterization of laser nanomaterials based on dye‐doped methyl methacrylate (MMA) crosslinked with octa(propyl‐methacrylate) polyhedral oligomeric silsesquioxane (8MMAPOSS) is reported in relation to their composition and structure. The influence of the silicon content on the laser action of the dye pyrromethene 567 (PM567) is analyzed in a systematic way by increasing the weight proportion of POSS from 1 to 50%. The influence of the inorganic network structure is studied by replacing the 8MMAPOSS comonomer by both the monofunctionalized heptaisobutyl‐methacryl‐POSS (1MMAPOSS), which defines the nanostructured linear network with the POSS cages appearing as pendant groups of the polymeric chains, and also by a new 8‐hydrogenated POSS incorporated as additive to the polymeric matrices. The new materials exhibit enhanced thermal, optical, and mechanical properties with respect to the pure organic polymers. The organization of the molecular units in these nanomaterials is studied through a structural analysis by solid‐state NMR. The domain size of the dispersed phase assures a homogeneous distribution of POSS into the polymer, thus, a continuous phase corresponding to the organic matrix incorporates these nanometer‐sized POSS crosslinkers at a molecular level, in agreement with the transparency of the samples. The silicon–oxygen core framework has to be covalently bonded into the polymer backbone instead of being a simple additive and both the silica content and crosslinked degree exhibit a critical influence on the laser action.     

Modified-atmosphere packaging (MAP) does not affect the bioavailability of tocopherols and carotenoids from broccoli in humans: A cross-over study

Aim of the study

Ready-to-eat and pre-packed vegetables are increasingly accepted by consumers but little is known about the effect of these technological approaches on the bioavailability of the nutrients. To assess the effect of modified-atmosphere packaging (MAP) on the bioavailability in humans of carotenoids and tocopherols from broccoli.

Results

Serum lutein increased significantly upon broccoli intake but those of β-carotene, α- and γ-tocopherol did not reach statistical significance. Serum changes were observed regardless of the type of broccoli consumed.

Conclusions

Modified-atmosphere packaging does not affect significantly the in vivo bioavailability of carotenoids and tocopherols from broccoli, supporting its convenience for use by the food industry and consumers.     

Sensory analysis integrated by palynological and physicochemical determinations plays a key role in differentiating unifloral honeys of similar botanical origins (Myrtaceae honeys from southern Spain)

Myrtaceae honeys produced in Sierra Morena (southern Spain, Andalusia) are obtained from both Eucalyptus camaldulensis and Myrtus communis, and honeys can be easily confused when classified as they come from the same botanical family. The characterisation was intended on the basis of their physicochemical, sensory and palynological properties. Cluster analysis (CA) and principal component analysis (PCA) allowed us to make a distinction between two honey profiles. The first one corresponds to the European sensory profile described for Eucalyptus unifloral honeys. The second profile, which sensory characteristics are absolutely different, has not been previously described. Classification of samples is proposed to be based on their pollen type and content and sensory attributes. Therefore, pollen type and content in E. camaldulensis and M. communis are required to distinguish Eucalyptus honey type from other honeys coming from Myrtaceae family. Sensory analysis identifies honey botanical source as well as palynological analysis: Eucalyptus sensory profile requires over 50% of E. camaldulensis and under 30% of M. communis pollen. Previously undefined sensory profile of myrtle honey is showed under 50% of E. camaldulensis and over 30% of M. communis pollen.     

Harmful effects of un-ionised ammonia on the zooplankton community in a deep waste treatment pond

The harmful effects of NH(3) on the zooplankton community in a deep waste treatment pond were evaluated under natural conditions. The pond, supplied with secondary effluent from a conventional urban wastewater treatment plant, was designed to improve water quality for agricultural reuse.The aim of the study was to verify the hypothesis suggested in Arauzo et al. (Water Environ. Res. 34(14), 3666) that during phytoplankton blooms in the stratification periods high un-ionised ammonia content values, due to an intense photosynthetic activity and high related pH, lead to a decrease in zooplankton biomass and, thus, to a collapse of the treatment process efficiency.Empirical models were developed to determine relationships between phytoplankton biomass, pH and NH(3) levels. They provided an easy and quick method of detecting when the system was liable to collapse due to the NH(3) effect on the zooplankton community and offered the possibility of adopting measures to guarantee water quality at the effluent. A significant decrease in zooplankton community biomass was observed at un-ionised ammonia levels over 2.5 mgL(-1).     

Well-dispersed Rh nanoparticles with high activity for the dry reforming of methane

Rh catalysts with low Rh content were prepared by incipient wetness impregnation using [NH₄]₃[RhCl₆]·3H₂O or RhCl₃·3H₂O as precursor salts, on CaO–SiO₂ supports. All solids showed a high stability after 48 h on stream for the dry reforming of methane with low carbon content, which made them suitable for obtaining ultrapure hydrogen in a membrane reactor. The methane conversion and hydrogen recovery were measured increasing the sweep gas flow rates to rise the driving force for hydrogen permeation. The catalyst with 0.36 wt.% of Rh showed a slight deactivation. However, the Rh(0.6)/CaO–SiO₂ solid, in which the Rh impregnation was performed using [NH₄]₃[RhCl₆]·3H₂O, exhibited an increase on CH₄ conversion of 77% and a hydrogen recovery equal to 84%.Nanoparticles of about 1.4–1.7 nm surface average diameter were detected for the reduced and used solids indicating that Rh is well dispersed and sintering was not produced after the catalytic tests. Rh particle sizes calculated by CO chemisorption were coincident with those measured by Transmission Electron Microscopy. Characterization by this technique and Laser Raman Spectroscopy of the solids used in membrane reactor revealed the formation of scarce carbon filaments. However, a surface re-oxidation was detected in the low loading catalyst used in the membrane reactor suggesting that it is the main cause for the decrease in the activity of the highly dispersed catalyst.     

Cloning and sequence analysis of the Pichia pastoris TRP1, IPP1 and HIS3 genes

The Pichia pastoris TRP1 and HIS3 genes were cloned by complementation of the Saccharomyces cerevisiae trp1 and his3 mutants, respectively, and their nucleotide sequence was determined. The P. pastoris TRP1 gene includes an open reading frame (ORF) of 714 nucleotides corresponding to a polypeptide of 237 amino acids whose sequence shares about 40% identity with that of TRP1 encoding proteins in other yeast species. DNA sequencing showed that an ORF of 858 nucleotides, encoding a protein of 285 amino acids with high homology to inorganic pyrophosphatases (IPP1), is located downstream of the P. pastoris TRP1 gene. Both genes converge in this chromosomal region, showing a genetic organization analogous to that found in the Kluyveromyces lactis genome. The P. pastoris HIS3 gene possesses an ORF of 675 nucleotides, encoding a polypeptide of 224 amino acids which shows 74·1% identity to the homologous S. cerevisiae protein. The hexameric consensus GCN4 binding sequence (TGACTC), characteristic of many amino acid biosynthetic genes, is present in the promoter region. The TRP1 and IPP1 sequences were deposited in the EMBL databank under Accession Number AJ001000. The Accession Number of the HIS3 gene is U69170. © 1998 John Wiley & Sons, Ltd.     

New Insights in the Involvement of the Endocannabinoid System and Natural Cannabinoids in Nicotine Dependence

Nicotine, the main psychoactive component in tobacco smoke, plays a major role in tobacco addiction, producing a high morbidity and mortality in the world. A great amount of research has been developed to elucidate the neural pathways and neurotransmitter systems involved in such a complex addictive behavior. The endocannabinoid system, which has been reported to participate in the addictive properties of most of the prototypical drugs of abuse, is also implicated in nicotine dependence. This review summarizes and updates the main behavioral and biochemical data involving the endocannabinoid system in the rewarding properties of nicotine as well as in nicotine withdrawal and relapse to nicotine-seeking behavior. Promising results from preclinical studies suggest that manipulation of the endocannabinoid system could be a potential therapeutic strategy for treating nicotine addiction.     

Foam aptitude of Bobal variety in white sparkling wine elaboration and study of volatile compounds

Fining agents can also have an effect on the flavor components of the must, and other compounds which are important for the sensory characteristics and in the case of sparkling wine, the foam quality. The influence of fining agents and tirage solution, on volatile compounds, and foam characteristics of sparkling wines made from grapes of the Bobal variety was studied. The data obtained show how the fining agent affects the foam properties and the final volatile composition of sparkling wines. In this study, it was bentonite with gelatine that produced amounts of acetates and esters. The use of Colle 2P in the tirage solution means that more aromatic sparkling wines with better foam characteristics can be obtained.