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Chemical and Ecotoxicological Characterization of Averno Lake
No full textThe scope of present paper is to carry out a model study on the lake Averno, a nearly water closed basin polluted by waste waters of nearby communities and by agricultural activities. Lake Averno is a natural basin in the Phlegrean Fields region about 15 km west of Naples (Italy). This lake was formed as a consequence of the collapsing of a large volcano, named Archiflegreo, which was active until historic times. The area around Phlegrean Fields presents signs of thermo-mineral spring streams (at Bagnoli, Pozzuoli and Lucrino) and natural (at Averno and Fusaro) spring streams (Martini et al. 1991; Celico et al. 1992). The water flowing into Lake Averno is essentially soft, with an average a flow rate of 42 dm3/s during the rainy seasons and almost zero in the summer months. The water basin is nearly elliptic (1000 m long and 700 m wide), covering a 0.54 km2 surface, and is 34 m deep at the center, with a total water volume of roughly 6.000.000 m3. A canal which is almost 1 km long links the lake to the sea, carrying both spring and rain waters to the Lucrino coast in the Gulf of Pozzuoli (Cortini and Scandone 1987). The discharge into the sea trough this canal and the sedimentation constitute outputs of lake pollutants. Around the crater terraces with citrus fruits and vineyards are irrigated with the lake water. However Lake Averno is heavily polluted by the urban waste waters from overflows of the collector that carries residual waters into the Cuma Plant
Hydrophobic interactions in the aqueous solutions of alkane-1,2-diols. Calorimetric and spectroscopic studies at 298.15 K.
No full textEnthalpies of diln. in water were detd. for ternary aq. solns. contg. two of the following alkane-1,2-diols: ethane-1,2-diol, propane-1,2-diol, butane-1,2-diol, pentane-1,2-diol and hexane-1,2-diol. The derived enthalpic interaction coeffs. are interpreted in terms of the interaction of two hydrated mols. through a preferential orientation, side on, stabilized by the prefered interaction between the hydroxyl groups. Other effects are considered, which lead to a unifying rationalization, common to alkanols and other isomeric diols. Further evidence for a side on orientation is given by nuclear relaxation time studies on the binary and ternary aq. solns. of propane-1,2-diol and hexane-1,2-diol
Empirical correlations between thermodynamic and spectroscopic properties of aqueous solutions of alkan-m,n-diols: excess enthalpies and spin-lattice relaxation times at 298.15 K.
No full textThe heats of diln. in water and nuclear relaxation times at 298.15 were detd. for binary aq. solns. contg. alkan-a,w-diols and for ternary aq. solns. contg. the probe mol. hexane-1,2- or hexane-1,6-diol and one of the members of the homologous series of alkane-1,2-diols and of alkane-a,w-diols, up to heptane-1,7-diol. The results were interpreted through the model of preferential orientation, i.e. the "side-on" model, already proposed to explain the interactions in soln. between various positional isomers of hydroxylated substances. For binary solns., a correlation is presented between the relaxation times and the enthalpic self-interaction coeffs
Sintesi di blocchi poliesterammidici potenzialmente biodegradabili, contenenti segmenti di poli(L, L-Lattide).
No full textSynthesis, purification, NMR characterization and interaction with nucleotides of a fragement of a human protamine.
No full textThe peptide Arg-Arg-Ser-Ser-Ser-Arg-Pro-Ile-Arg-Arg (peptide I), which is a common fragment in many fish protamines, was previously suggested to promote strong purine nucleotide binding in these proteins. To verify this hypothesis, peptide I was synthesized by the solid-phase technique and purified by cation-exchange chromatog. The peptide was characterized by mono- and bi-dimensional NMR spectroscopy. NMR resonances were fully assigned both in the proton- and in the 13C-aliph. regions of the spectra. The interactions of the peptide with purine and pyrimidine mononucleotides in aq. solns. have been studied as a function of nucleotide concn. The addn. of pyrimidine nucleotides did not produce any relevant effect in the NMR spectrum. The presence of a purine nucleotide, on the contrary, produced remarkable upfield chem. shifts and a strong broadening of the peptide resonances. In the case of 5'-dGMP this broadening was accompanied by a very large redn. of the area of the peptide resonances. These results complement the behavior of fish protamines previously tested contg. the peptide I sequence, and fully support the original hypothesis
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