Enhancing high-order harmonic generation in light molecules by using chirped pulses

One of the current challenges in high-harmonic generation is to extend the harmonic cutoff to increasingly high energies while maintaining or even increasing the efficiency of the high-harmonic emission. Here we show that the combined effect of down-chirped pulses and nuclear dynamics in light molecules allows one to achieve this goal, provided that long enough IR pulses are used to allow the nuclei to move well outside the Franck-Condon region. We also show that, by varying the duration of the chirped pulse or by performing isotopic substitution while keeping the pulse duration constant, one can control the extension of the harmonic plateauWe gratefully acknowledge fruitful discussions with Y.Mairesse. This work has been accomplished with a generous allocation of computer time from Mare Nostrum BSC and CCC-UAM and has been partially supported by the European Research Council Advanced Grant No. XCHEM 290853, MINECO Project No. FIS2013-42002-R, ERA-Chemistry Project No. PIM2010EEC-00751, European Grant No. MC-ITN CORINF, European COST Action XLIC CM1204, and the CAM project NANOFRONTMAG. R. E. F. S. acknowledges FCT—Fundação para a Ciência e Tecnologia, Portugal, Grant No. SFRH/BD/84053/201

Effect of Associations of Additives on pH and NDF in Sugar Cane Silages (\u3cem\u3eSaccharum officinarum\u3c/em\u3e)

An alternative to the seasonality of forage production in grazing-lands is the maintenance of feed supplies through the use of silages (Carvalho et al. 2007). Sugar cane stands out for silage production, mainly because of its high yield per hectare. There are, however, restrictions to its use in cattle production systems including the daily cutting demands, low digestibility of fiber and low contents of protein and minerals. Sugar cane ensiling can solve, or even reduce the seasonality of the crop and the losses by fire or frost, and has been utilized in cattle raising for these logistic and operational benefits. The fermentative losses of sugar cane silage can, however, make its utilization unviable. The predominance of alcoholic fermentations in those silages requires additives to improve the aerobic stability and reduce dry matter losses. The additives act upon the fermentation of silage, alter the ensiled mass and inhibit the development of undesirable microorganisms in the fermentation (Santos 2007). In spite of the great volume of studies in recent years on the use of additives in sugar cane ensiling, whether it be bacterial, chemical or organic, there is still significant discrepancy between the results. The aim of this work was to evaluate the effect of different associations of additives on pH and on the neutral detergent fiber contents in sugar cane silages

Green processing of porous chitin structures for biomedical applications combining ionic liquids and supercritical fluid technology

The application of green chemistry principles in the processing of materials for advanced technologies is a steadily increasing field of research. In this work porous chitin-based materials were developed by combining the processing of chitin using ionic liquids (ILs)as a green solvent together with the use of super- critical fluid technology(SCF) as clean technology.Chitin was dissolved in 1-butyl-3-imidazolium acetate,followed by regeneration of the polymer in ethanol in specific moulds.The IL was removed using Soxhlet extraction and successive steps of extraction with SCF using carbon dioxide/ethanol ratios of 50/ 50 and70/30.The developed porous chitin-based structures (ChIL)can be classified as mesoporous materials,with very low density and high porosity.The cytotoxicity of ChIL extracts was investigated using L929 fibroblast like cells,and the results demonstrated that the produced materials have extremely lowcytotoxicityl evels.Therefore,the findings suggest that the porous chitin structures may be potential candidates for a number of biomedical applications,including tissue engineering.Fundação para a Ciência e Tecnologia (FCT)S.S.S. and A.R.C.D. thank the Portuguese Foundation for Science and Technology (FCT) for post-doctoral fellowships (SFRH/BPD/ 45307/2008 and SFRH/BDP/34994/2007, respectively). This work was partially supported by the FCT (Project PTDC/QUI/68804/ 2006) and was carried out under the scope of the European NoE EXPERTISSUES (NMP3-CT-2004-500283)

2,2′,5,5′-Tetra­methyl-1,1′-(hexane-1,6-di­yl)di-1H-pyrrole

The mol­ecule of the title compound, C18H28N2, composed of two 2,5-dimethyl­pyrrole groups linked by a hexane chain, lies across a crystallographic inversion centre. The mean plane of the pyrrole ring is almost perpendicular to the mean plane of the central chain, making a dihedral angle of 89.09 (8)°. The crystal structure is stabilized by inter­molecular C—H⋯π inter­actions