186,921 research outputs found
P. Filippani-Ronconi. Canone buddhista, Discorsi brevi
No full textBareau André. P. Filippani-Ronconi. Canone buddhista, Discorsi brevi. In: Revue de l'histoire des religions, tome 179, n°1, 1971. pp. 90-91
Mlle. Ronconi
No full textTitle from unverified information on negative sleeve.Daughter of M. Ronconi (LC-BH82-4878) see Frank Leslie Oct. 20, 1866; p. 69; Prima Donna.Forms part of Brady-Handy Photograph Collection (Library of Congress)
Intervista a Luca Ronconi
No full textin BOSISIO P. (a cura di), I due gemelli veneziani, programma di sala dello spettacolo diretto da Luca Ronconi, MIlano, Piccolo Teatro di Milan
Mlle. Ronconi
No full textTitle from unverified information on negative sleeve.Daughter of M. Ronconi (LC-BH82-4878) see Frank Leslie Oct. 20, 1866; p. 69.Forms part of Brady-Handy Photograph Collection (Library of Congress)
Spin-dependent conductivity of nanosized magnetic inhomogeneities
No full textSpin-dependent scattering (SDS) originates at the interface between magnetic (M) and non-magnetic (NM) regions, and gives rise to the giant magnetoresistive effect (GMR), that is observed when M and NM regions are interleaved at the nanoscale level. The GMR intensity, i.e. the change in resistivity observed due to the application of an external magnetic field, is affected by the SDS strength that, in its turn, is inversely proportional to the lateral size of the magnetic regions [1]. Such a lateral scale is the effective size of the magnetic regions [2], Deff, that is the result of the effect of magnetic interactions on the real size of the magnetic regions, D. Similarly, if the magnetic morphology of the system is not uniform, the SDS strength changes with the lateral scale of the magnetization inhomogeneities [3].
The dependence of GMR on the external field is the counterpart of Deff, so direct indications about D are not easily accessed. However, if we resort to the GMR efficiency, gamma, [4], i.e. the change in GMR for a unit change of squared magnetization, the comparison between the values of gamma measured at low and at high applied field as a function of Deff enables one to evidence D with respect to Deff. Indeed, if Deff is larger than D, as soon as the external applied field overcomes the effect of magnetic interactions, the efficiency of the magnetic structure is expected to change, as the large effective magnetic volumes break into smaller parts. As a consequence of that, the lateral scale of the system decreases, and gamma is expected to increase accordingly.
In this work, we study different FexAg1-x nanogranular systems, where x is the relative Fe atomic concentration, 0.1 < x < 0.5. Under equilibrium conditions, Fe and Ag are not miscible, so using an out-of-equilibrium technique, in our case dc-magnetron sputtering, we obtain a deep intermixing of the two species. In this way, as a function of x, different samples with a different average magnetic length scale, namely with a different Deff, can be produced [3]. The evolution of the magnetic morphology of the systems was followed with zero-field-cooled and field-cooled magnetization measurements. Magnetization and GMR loops were recorded at two different temperatures, at 300 K and at 4 K. Indeed they represent two conditions were the contribution of interparticle interactions to systems dynamics is expected to be different. In this way, the effect of Deff can be better appreciated. We present the gamma dependence on x, measured both at low and at high applied field, gamma_L and gamma_H, respectively. For low values of x, gamma_L and gamma_H display the same dependence as a function of x, whilst for higher values gamma_L shows a broad maximum whilst gamma_L has a monotonic dependence that eventually approaches saturation. These data are presented and discussed and compared to magnetization loops and diffraction data in order to give an estimation of the Deff of the different samples.
[1] S. Zhang and P. M. Levy, J. Appl. Phys. 73, 5315, 1993.
[2] P. Allia, M. Coisson, F. Spizzo, P. Tiberto, F. Vinai, Phys. Rev. B 73 (2006) 054409
[3] P. Vavassori, E. Angeli, D. Bisero, F. Spizzo, F. Ronconi, J. Magn. Magn. Mater. 262 (2003) 52
[4] M. Tamisari, F. Spizzo, F. Ronconi, M. Sacerdoti, G. Battaglin, submitted to Journal of Applied Physics
Per Luca Ronconi (1933-2015): quasi una «leçon de ténèbres»
No full textThe recent death of Luca Ronconi (February 21st, 2015) became the occasion to retrace his artistic path, of a forever restless ‘adolescent’, and to understand better his typical traits. Among projects that will remain forever unfulfilled, titanic failures and visionary shows, the keystone of the poetics of Ronconi turns out to be an inexhaustible search of the infinite, in a dialectic between the exceeding of the limit and the strenuous comparison with its inescapable necessity. The theatre of Ronconi, in its giddy pursuit of ‘what has no end’, confesses its most genuine nature: an ‘anatomical’ theatre of death.</p
Applications of heteronuclear NMR spectroscopy in biological and medicinal inorganic chemistry
No full textThere is a wide range of potential applications of inorganic compounds, and metal coordination complexes in particular, in medicine but progress is hampered by a lack of methods to study their speciation. The biological activity of metal complexes is determined by the metal itself, its oxidation state, the types and number of coordinated ligands and their strength of binding, the geometry of the complex, redox potential and ligand exchange rates. For organic drugs a variety of readily observed spin I = 1/2 nuclei can be used (H-1, C-13, N-15, F-19, P-31), but only a few metals fall into this category. Most are quadrupolar nuclei giving rise to broad lines with low detection sensitivity (for biological systems). However we show that, in some cases, heteronuclear NMR studies can provide new insights into the biological and medicinal chemistry of a range of elements and these data will stimulate further advances in this area. (C) 2008 Elsevier B.V. All rights reserved
Using coordination chemistry to design new medicines
No full textThe rich diversity of coordination chemistry provides exciting prospects for the design of novel therapeutic agents with unique mechanisms of action. Central to such discovery is the understanding of both the kinetics and thermodynamics of reactions of metal complexes under conditions of biological relevance, and consideration of the roles of both the metal and its ligands in recognition processes. Examples from our recent work are reported here and discussed. Xylylbicyclam is a potent anti-HIV agent and is in clinical use as a stem-cell-mobilizing drug (AMD3100, "Mozobil"). Its target is the 7-helix membrane receptor CXCR4. Specific metallomacrocycle configurations can be recognized by proteins via metal coordination to specific amino acid side-chains, H-bonding and hydrophobic interactions, allowing optimisation of drug design. Photoactivation of octahedral cis and trans diam(m)ino diazido Pt(IV) complexes can lead to unusual redox and substitution reactions. Such activated complexes can kill cancer cells by novel mechanisms of action, providing a basis for a novel form of photochemotherapy. Substitution and redox reactions and the anticancer activity of Ru(II) arene complexes of the type [(η6-arene)Ru(X)(YZ)] are highly dependent on the nature of the arene, and monodentate (X) and chelated (YZ) ligands. Understanding of the factors which control such reactions has led to the rational design of analogous osmium anticancer complexes
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