196,118 research outputs found
Influence of long-term residue and fertilizer applications on soil humic substances: A study by electrofocusing
No full textSoil samples were taken from the plots of an experimental field that had been treated continuously for 22 years with different residue and fertilizer applications (cereal residues, cattle manure, NH4NO3). The electrofocusing (EF) technique was used to characterize the humic substances extracted from these soils with 0.5 M NaOH. The EF patterns of the organic matter extracted from the soil which had received applications of cattle manure showed many bands focused in the typical pH gradient region of the most humified compounds. The EF patterns of the organic matter extracted from both unfertilized soil and from soils amended with straw appeared to be much less complex. The addition of NH4NO3 did not affect the soil organic matter characteristics investigated with the EF technique. The results obtained show that electrofocusing is a promising technique for the characterization of humic substances and may well be particularly useful in the evaluation of differences that occur in the humic substances in soil due to residue and organic fertilizer applications. © 1992 Williams and Wilkins
Characterization of methylprednisolone esters of hyaluronan in aqueous solution: conformation and aggregation behaviour
No full textCONFORMATION AND AGGREGATION OF METHYLPREDNISOLONE ESTERS OF HYALURONAN BY MEANS OF 1H PULSED GRADIENT STIMULATED ECHO NMR
No full textStudies on coffee roasting process by means of nuclear magnetic resonance spectroscopy
No full textThe chemical composition of coffee has been widely investigated, focusing the attention both on main components and trace compounds. Most of these studies have been performed by using liquid and gas chromatography, eventually combined with mass spectroscometry. These techniques, although straight and effective, are time demanding due to the sample pretreatments. Here, we propose high-resolution-magic-angle spinning nuclear magnetic resonance spectroscopy (HR-MAS NMR), a system capable of acquiring highly resolved NMR spectra of gel-like and suspension samples. This approach allowed us to determine the chemical composition of coarsely ground coffee beans of two varieties: Arabica and Robusta. Variation of the concentration of relevant species was monitored as a function of roasting temperature, from green beans to completely roasted. The HR-MAS NMR tool demonstrated to be very powerful for quick chemical composition determination, opening up possibilities for novel applications of this approach in food quality control
Effects of a fire event on the soil organic matter of a pine forest and a pasture
No full textThe effects of a fire onto the organic components of soils from a pine forest and a pasture, one close to the other and both located in the Italian Presidential Estate of Castelporziano (Roma), have been investigated. Chemical and biochemical indicators of soil organic matter (SOM) from two horizons, i.e. 0-5 and 5-20 cm, have been considered. Data were correlated with those obtained by means of solid state NMR spectroscopy (CPMAS 13C-NMR). The latter was applied to both whole soil and selectively extracted SOM and the percentage of aromatic functional groups and the alkylic to O-alkylic carbon ratio were measured. In pine forest the formation of recalcitrant and hydrophobic molecules, e.g. resins, melanoidins and condensed polymers, occurred. In pasture soil TEC, TOC, CHA+FA and microbial biomass increased in inverse proportion to the carbonyl group amount estimated by CPMAS 13C-NMR
METHYLPREDNISOLONE ESTER OF HYALURONAN AS A DELIVERY SYSTEM: PROTEIN RESISTANCE, CELL ADHESION AND DRUG RELEASE
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Pomodoro di Pachino: An Authentication Study Using 1H-NMR and Chemometrics – Protecting its P.G.I. European Certification
No full textIn recent years the problem of the objective assessment of authenticity of agro-food products has increased drastically. Due to the global market, the spreading of foodstuffs that were previously localized to well-defined geographical areas is made possible, and with this globalisation attempts to imitate high-quality food products are ever increasing. The European logos identifying Protected Designation of Origin (PDO) and Protected Geographical Indication (PGI) collective marks have been developed and used for branding those European food products that fulfill the requested and certified characteristics. In the present work the authenticity of the Italian cherry tomato “pomodoro di Pachino” with respect to some other Italian cherry tomatoes has been investigated utilizing proton High Resolution Nuclear Magnetic Resonance (1H HR NMR) as the analytical method and chemometrics as a tool for analyzing and interpreting the acquired multivariate data. The results indicate that the tomatoes produced in the Pachino area, indeed, are different, in terms of chemical quality, from all the non-authentic tomatoes investigated in this study
Internal structure and quality assessment of fresh truffle Tuber melanosporum by means of magnetic resonance imaging spectroscopy
No full textIn the present article, magnetic resonance imaging spectroscopy (MRI) was used to study fresh black truffle, with the aim of elucidating the internal structure, the effects of fungal invasion, and physical changes occurring in post-harvest. MRI is a non-destructive and non-invasive analytical technique offering the almost unique opportunity of studying foodstuff while leaving it intact, without any sample preparation. The internal morphology and modifications induced by external agents (e.g. fungal invasion, diseases, dehydration) are some of the aspects addressed by means of this innovative analytical tool
3D Volumetric Tomography as an innovative bridge between medicine, diagnostic, scientific and industrial research
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