1,721,050 research outputs found
Non ci resta che il piano
No full textRecensione al volume di G.Ave "Città e interesse pubblico. Analisi e proposte per le città italiane 1989-2020" Gangemi editore, Roma 202
The sudden character of the sudden polarization effect
No full textThe evolution of the suggested sudden polarization parameter in excited singlet states in one-end pyramidalized ethylene, propylene and butadiene during geometrical relaxation of the double bond was investigated. As the sudden polarization parameter decreases the energy gap grows between the corresponding excited polar states. © 1984
13C spin-lattice relaxation study of some amino-acid, their phospho-derivatives and some small peptides
No full textCarbon C-13 spin-lattice relaxation times, T1, of Serine, Threonine, Phospho-serine and Phosphothreonine have been measured in D2O at neutral pD. Changes in over-all motions under phosphorylation has been detected. Segmental motions are not affected by phosphorylation. With the aid of T1(C-13) values of other amino acids an empirical relationship between NT1 and molecular weights (Mw) is tested that seems valid also for small peptides. Such relationship allows to interpret results from T1 measurements with the aid of a simple spherical model. © 1984, Taylor & Francis Group, LLC. All rights reserved
Study of (1-alkoxyethyl)diphenylphosphine Oxides .3. Nuclear-magnetic-resonance Analysis
No full textSelective measurements of heteronuclear overhauser effects: Structural applications
No full textA NMR method for determining internuclear distances between dipolarly coupled nuclei is here proposed. As a model system, salicylaldehyde has been investigated. A selective presaturation of C1H and O2′ H protons yields Overhauser effects on C1, C1′ and C2′ resonances. From a combined use of these Overhauser effects and13C spin-lattice relaxation rates, internuclear distances between irradiated protons and carbon nuclei dipolarly coupled to them can be calculated. Furthermore, the obtained selective Overhauser effects can simultaneously evidentiate donor and acceptor moieties of hydrogen bonds, as in the present study in which the hydrogen bonding between the C1 carbonyl and the O2′ H proton was clearly delineated. © 1984 Societá Italiana di Fisica
1H-NMR relaxation studies of glycopeptides: a dynamic structural investigation
No full textThe Glycopeptide Man5GlcNAc4Asn (ACCB2) in water solution has been studied by means of 1H NMR relaxation techniques in order to define molecular structure and dynamics. From the analysis of selective and non-selective proton relaxation rates of selected ACCB2 protons, a lack of internal mobility along the polysaccharide chain was observed. The presence of a conformationally well-defined molecular structure for ACCB2 is proposed
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