Characterization of odour-active volatile compounds of acerola wine

The volatile compounds of acerola wine were isolated by headspace–solid phase microextraction (HS-SPME) and analysed by gas chromatography-flame ionization detector (GC-FID), gas chromatography-mass spectrometry (GC-MS), and gas chromatography-olfactometry (GC-O). The composition of acerola wine included 38 esters, 19 alcohols, 16 acids, 8 terpenes, 5 aldehydes, 5 ketones, 3 furans, and 8 miscellaneous compounds. The odour-active compounds were screened by application of the aroma extract dilution analysis and odour activity values. Nineteen odorants were considered as odour-active volatiles, from which methyl 2-methylbutanoate and 2-ethylhexan-1-ol were the most odour-active compounds

Highly cross-linked bifunctional magnesium porphyrin-imidazolium bromide polymer: Unveiling the key role of co-catalysts proximity for CO2 conversion into cyclic carbonates

Highly cross-linked materials containing an imidazolium salt and magnesium porphyrin, either in the absence (TSP-Mg-imi) or in the presence (7a and 7b) of multi-walled carbon nanotubes (MWCNTs), were synthesized and used as heterogeneous bifunctional catalysts for the conversion of CO2 into cyclic carbonates. The metalloporphyrin moiety acts both as a “covalent swelling agent”, generating hybrids with high surface area, and as a Lewis acid co-catalytic species. TSP-Mg-imi produced excellent conversion and TONMg values, under solvent-free conditions, even at room temperature and with low catalytic loading (0.003 mol%). In terms of conversion and TONMg, TSP-Mg-imi exhibited better catalytic performance compared to a reference homogeneous system, demonstrating that the proximity between the metal centers and the nucleophilic site results in a synergistic effect during the catalytic cycle. The results of the computational study confirmed both the cooperative function and the significance of incorporating a co-catalytic species into the system

Prevalencia relativa de los poliovirus en la ciudad de Lima (De enero de 1965 a enero de 1966)

Se realizó un intento de aislamiento de los virus de la Poliomielitis de muestras de heces de 174 pacientes internados en la Sección de Poliomielitis del Pabellón 7 del Hospital del Niño, cuyas edades fluctuaban entre los dos meses como mínimo y 12 años como máximo; 161 pacientes entre 2 meses, límite inferior y 2 años 6 meses, límite superior. El estudio fue realizado durante un año, de Enero de 1965 a Enero de 1966. Los aislamientos fueron hechos en cultivos de tejidos (cultivos primarios de riñón humano y cultivos de Hela). Se obtuvieron los siguientes resultados: de un total de 174 muestras de heces procesadas para aislar los poliovirus, 163 resultaron positivos (93.67%) y negativos 11 (6.33%). De las 163 cepas de poliovirus aisladas, 64 correspondieron al tipo I (39.26%), 64 al tipo II (39.26%) Y 35 cepas al tipo III (21.26%). Se hace un intento de explicación de esta modalidad de prevalencia relativa de los poliovirus (predominio de los tipos I y II sobre el III) en la ciudad de Lima y ocurrido en el lapso de un año, de Enero de 1965 a Enero de 1966

Surface-enhanced Raman scattering study of L-tryptophan

Surface-enhanced Raman scattering (SERS) spectra of tryptophan (Trp) were obtained. A unique SERS spectrum of Trp, corresponding to the most stable conformation and orientation on the metal surface, is observed after a stabilization period. The Trp molecules interact with the surface through both the carboxylate and amino groups; the aliphatic moiety is close to the surface. The pyrrole ring of the indolemoiety is farther from the surface than the benzene fragment. The observed spectra vary depending on both the preparation of the silver colloid and the aggregation time. The interpretation of the experimental results is supported by theoretical treatment of themolecule on the silver surface. Copyright © 2008 John Wiley & Sons, Ltd