117,661 research outputs found
Self-assembly of doxorubicin into gels
No full textSelf-assembly of doxorubicin into gels
Elisamaria Tasca1*, Mauro Giustini1,2, Marco D’Abramo1, Luciano Galantini1,2, Gerardo Palazzo2,3
1 Chemistry Dept., “La Sapienza” University, P.le Aldo Moro 5, 00185-Rome, [Italy]
2 CSGI (O.U. of Bari), Chemistry Dept., University of Bari, 70126 Bari [Italy]
3 Chemistry Dept., University of Bari, Via Orabona 4, 70126-Bari, [Italy]
*[email protected]
The closely related anthracyclines doxorubicin (DX), daunomycin (DN) and epirubicin (EPI) in aqueous solution are present essentially as dimers at concentrations above or equal to 10-5M. However, DX, but not DN and EPI, in the presence of NaCl, at concentrations above a threshold value that depends also on the DX concentration, gives rise to gels [1-2].
The properties of these gels have been studied by UV-Vis, circular dichroism (Figure 1-A), steady-state and time resolved fluorescence (TCSPC - Figure 1-B) spectroscopy and SAXS (Figure 1-C), supported by MD simulations and fluorescence microscopy. The experimental results and the simulations suggest self-assembly of the somewhat distorted dimers in supramolecular aggregates, possibly in the form of fibrils, that would aggregate into larger structures to give the gels [3].
References
[1] M. Giomini, A.M. Giuliani, M. Giustini and E. Trotta, Biophys. Chem., 1992 (45) 31.
[2] E. Hayakawa, K. Furuya, T. Kuroda, M. Moriyama and A. Kondo, Chem. Pharm. Bull., 1991 (39) 1282.
[3] M. Giustini, A.M. Giuliani, E. Tasca, M. D’Abramo, L. Galantini and G. Palazzo, manuscript in preparation
Il Direttore Generale dell\u27Istruzione superiore invita il direttore di Ca\u27 Foscari a dare accoglienza a degli universitari giapponesi in viaggio (Roma, 28 luglio 1938)
No full textIl Direttore Generale dell\u27Istruzione superiore, Giuseppe Giustini, scrive al direttore del R. Istituto Superiore di Economia e commercio, Agostino Lanzillo, e per conoscenza al direttore del R. Istituto Superiore di Architettura, Guido Cirilli, per informarli della presenza in Italia di una comitiva di studenti e professori giapponesi dell\u27università di Kyoto per un viaggio di istruzione e di studio.
Durante la permanenza, gli studenti visiteranno le università e gli istituti superiori: trovandosi a Venezia dal 29 luglio all\u271 agosto [1938], Giustini prega Lanzillo e Cirilli di offrire la dovuta accoglienza agli studenti, avvertendoli che "l\u27organizzazione logistica" è affidata al GUF.Lettera dattiloscritta su carta intestata del Ministero dell\u27Educazione Nazionale . Direzione Generale della Istruzione Superiore, con firma autografa del Capo di Gabinetto del Ministro dell\u27Educazione Nazionale nonchè Direttore Generale dell\u27Istruzione Superiore e dell\u27Ordine Universitario (G. Giustini). Il verso del documento è privo di scrittura
The role of the cosurfactant in the CTAB/water/n-pentanol/n-hexane system: Pentanol effect on the phase equilibria and mesophases structure
No full textWe report on the effect of 1-pentanol loading on the phase behaviour of mixtures of CTAB/water/n-hexane at fixed mole ratios 1:80:47. The cosurfactant induces changes in the interfacial film curvature. By increasing the pentanol/CTAB mole ratio, the system evolves from oil-in-water to water-in-oil structures. For very large 1-pentanol loading some water is expelled from the reverse micelles resulting in a L(2) plus water equilibrium (emulsification failure). In the range of compositions investigated most of the phase equilibria reveals the coexistence of liquid crystals and hexane/pentanol solutions. In these cases, we estimate the interface composition by assuming a constant 1-pentanol concentration in all the oil domains, and by tacking into account the alcohol solubility in water. In the case of single-phase sample the interfacial composition was determined by means of turbidimetric titration. The adsorption of cosurfactant at the interface of direct micelles, planar lamellae, bicontinuous microemulsions, and spherical reverse micelles follows the same adsorption isotherm (independently from the curvature of the interface). Moreover, the results obtained unambiguously show that the interface composition dictates the spontaneous curvature of interfacial film. Actually positive, null, and negative curvatures correspond to different compositions of the interfacial film. Once the influence of cosurfactant on the spontaneous curvature of the interface is understood, the appearance of the emulsification failure upon pentanol loading can be rationalised within the framework of the flexible surface model
SYNTHESIS OF BENZOFURANONES VIA MALONATES DESYMMETRIZATION
No full textSYNTHESIS OF BENZOFURANONES VIA MALONATES DESYMMETRIZATION.
S. Placidi,a A. Puglisi,a C. Giustini,a A. Ricucci,a E. Perrotti,a L. Massaro,a D. Morra,a F. Ciucci,a A. Zucchet,a A. Antenucci,a M. Moliterno,a R. Salvio,a,b M. Bellaa
aDepartment of Chemistry, “Sapienza” University of Roma, P.le Aldo Moro 5, 00185 Roma; bIMC-CNR, Sezione Meccanismi di Reazione, P.le Aldo Moro 5, 00185 Roma; e-mail: [email protected]
Benzofuranones are interesting molecules due to their biological activity.1 Up today few studies have been conducted with respect to their synthesis compared to the corresponding oxindoles. The enantioselective synthesis of these compounds is currently carried out starting from pre-assembled benzofuranone moiety.2 In this work we present the synthesis of chiral, non-racemic benzofuranones, based on an asymetric intramolecular desymmetrization, catalyzed by Cinchona alkaloids and derivates, like quinine and catalyst I.3 Benzofuranones 4 are achieved by the addiction of malonates 1 to quinones 2 to give arylated achiral malonates 3 that subsequently undergo a cyclization reaction (Scheme1). Desymmetrization is an efficient metod for the synthesis of enantioenriched compounds starting from prochiral molecules.4 This approach allows to obtain products with high yields, up to 95%, and enantiomeric ratios as high as 97.5:2.5, in the best cases.
Scheme 1. Synthesis of benzofuranones organocatalyzed by Cinchona alkaloids and proposed transition state leading to the major enantiomer (R).
References
1. For examples see: a) K. M. Dawood, Expert Opin. Ther. Patents 2013, 23, 1133; b) C. Charrier, J. Clarhaut, J.-P. Gesson, G. Estiu, O. Wiest, J. Roche, P. Bertrand, J. Med. Chem. 2009, 52, 3112. 2. Y. Li, X. Li, J.-P. Cheng, Adv. Synth. Catal. 2014, 356, 1172.
3. A. Puglisi, C. Giustini, A. Ricucci, E. Perrotti, L. Massaro, D. Morra, F. Ciucci, A. Zucchet, A. Antenucci, M. Moliterno, S. Placidi, F. Sciubba, L. Galantini, R. Salvio, M. Bella, Chem. Eur. J. 2018, 24, 6945.
4. X. P. Zeng, Z. Y. Cao, Y. H. Wang, F. Zhou, J. Zhou, Chem. Rev. 2016, 116, 7330
Theoretical-computational modelling of the L-alanine CD spectrum in water
No full textHere we present an advanced theoretical-computational approach to model the electronic circular dichroism (CD) spectrum of the smallest chiral amino acid in water solution. Combining quantum–mechanical calculations with molecular dynamics simulations the electronic and magnetic properties of L-alanine (L-Ala) in solution are obtained and compared with the corresponding experimental measurements in the same conditions. The calculation of the CD spectrum, in good agreement with the experimental data, revealed a remarkable dependence on the conformational behavior of the molecule in solution, which was properly treated by our approach
Size distribution in emulsions
No full textEmulsions are generally opaque and scatter light widely. This characteristic is a considerable obstacle to the use of optical techniques such as dynamic light scattering and optical microscopy.
However, the optical appearance of a sample is totally irrelevant for nuclear magnetic resonance (NMR) measurements. In this paper we use general methods to calculate the size distribution of a collection of droplets in dilute emulsion systems using NMR pulse gradient spin-echo measurements. We show that such methods are also successful in describing a bimodal distribution of droplets
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