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M. Belli A. Scafati A. Bianconi E. Burattini S. Mobilio C. R. Natoli L. Palladino A. Reale 《Il Nuovo Cimento D》1983,2(5):1281-1304
Summary The binding of Mn2+ ions to ATP molecules has been studied by means of the fine-structure analysis of X-ray absorption spectra (EXAFS and XANES)
at theK-edge of Mn using the synchrotron, radiation facility PULS in Frascati. The results obtained in both freeze-dried and liquid
samples of aqueous solutions at room temperature of the Mn-ATP complex under diffrent values ofpH and Mn:ATP ratio are reported and discussed. The Mn2+ ion appears to be octahedrally coordinated, the phosphate oxygen atoms being in the first co-ordination shell. Values of
(2.15±0.05) ? and (3.4±0.05) ?, respectively, have been found for Mn-O and Mn-P distances. Theoretical considerations together
with experimental results do not support the existence of a direct binding of the Mn to the N(7) atom of the adenine ring.
The coordination numbers for the first and second shell are consistent with the formation of a Mn(ATP)2 complex in solution atpH=9 and Mn: ATP=1:10, while a Mn-ATP 1:1 complex is found at lowerpH and higher Mn: ATP ratios.
To speed up publication, the authors of this paper have agreed to not receive the proofs for correction. 相似文献
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M. De Crescenzi A. Balzarotti F. Comin L. Incoccia S. Mobilio N. Motta 《Solid State Communications》1981,37(12):921-923
The EXAFS structure measured above the K-edge of Fe in the disordered Fe80B20 alloy is reported. Complete agreement is obtained with X-ray diffraction results in the position of the first neighbours coordination shell when the asymmetry of the Radial Distribution Function (R.D.F.) into the EXAFS formula is included. A Finney-like R.D.F. is used to describe the pair distribution of these metallic glasses. The weak temperature dependence of the spectra is discussed in terms of the structural properties of these amorphous alloys. 相似文献
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A two step sequence converts certain cyclic enones to fused methylenecyclopentanes using the annulation reagent 2-chloromethyl-3-trimethylsilylpropene. 相似文献
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R. Torchio C. Meneghini S. Mobilio G. Capellini J. Alonso V. Turco Liveri A.M. Ruggirello 《Journal of magnetism and magnetic materials》2010,322(21):3565-3571
The magnetic response of nanometer sized Co nanoparticles (NP) prepared using reverse micelle solutions are presented. The use of complementary structural and morphological probes (like transmission electron microscopy, high resolution electron microscopy, X-ray absorption spectroscopy) allowed to relate the magnetic properties to the size, morphology, composition and atomic structure of the nanoparticles. All data agree on the presence of a core-shell structure of NPs made of a metallic Co core surrounded by a thin Co-oxide layer. The core-shell microstructure of NPs affects its magnetic response mainly raising the anisotropy constant. 相似文献
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Four new benzo- and tetrahydrobenzo-psoralens have been examined in their reversible interaction toward DNA and in their DNA-photobinding properties. These compounds were also examined for their ability to produce singlet oxygen and in vivo skin photosensitization reaction. Fluorescence and equilibrium dialysis measurements show that the complexation ability of benzoderivatives is remarkably high. Binding is less effective in the case of the tetrahydrocongeners. All compounds photoreact quite effectively to DNA. The photoadducts were obtained by enzymatic hydrolysis of drug-modified DNA and were characterized by high performance liquid chromatographic elution techniques. The 3,4 position represents the unique photoreactive site for benzopsoralens. Denaturation-renaturation experiments confirm that the benzoderivatives are purely monofunctional, while the tetrahydrocongeners form interstrand cross-links, even though to a remarkably lesser extent than 8-methoxypsoraien (8-MOP). The new compounds, in the presence of long-wavelength ultraviolet radiation, are very moderately effective in forming reactive oxygen species; they are ineffective in promoting oxidation of tyrosine and 3-(3,4-dihydroxyphenyl)alanine to do-pachrome and melanin. Skin photosensitizing experiments on guinea pigs indicate that benzo- and tetrahydroben-zopsoralen derivatives are almost devoid of any phototoxic effects. Thus, this class of compounds appears to be interesting for the development of new, less phototoxic chemotherapeutic agents that interact with DNA better than 8-MOP. 相似文献
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Cu-Ni alloy nanocluster formation by ion implantation in silicate glasses: Structure and optical properties 总被引:1,自引:0,他引:1
F. D'Acapito G. Battaglin E. Cattaruzza F. Gonella C. Maurizio P. Mazzoldi S. Mobilio F. Zontone 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2000,10(1):123-129
Sequential ion implantation (copper and nickel) in silica and soda-lime glasses has been performed. The formation of copper-nickel
alloy nanocluster in the glass host has been evidenced by synchrotron radiation-based techniques, namely X-ray diffraction
and absorption spectroscopy. The nanocrystals' lattice parameter value was estimated, indicating the formation of Cu55Ni45 alloy particles. Optical absorption spectra are also discussed.
Received 6 May 1999 and Received in final form 22 September 1999 相似文献
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A. Balerna L. Liotta A. Longo A. Martorana C. Meneghini S. Mobilio G. Pipitone 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1999,6(1):89-97
Silver-palladium bimetallic clusters were synthesized on pumice by the reduction of aqueous solution of metal salts with different
Pd:Ag ratios. Used as bimetallic catalysts, in hydrogenation reactions, in situations where molecules can undergo several
different reactions, they eliminate undesired reactions and maximize the desired ones. To characterize the structure of these
bimetallic catalysts and control if the two metallic elements do mix or not to each other to form an alloy, the structure
of the Ag-Pd bimetallic clusters was investigated by means of X-ray-absorption fine-structure spectroscopy (XAFS) and anomalous
wide angle X-ray scattering (AWAXS) experiments performed at the European Synchrotron Radiation Facility (ESRF) using the
GILDA and the BM16 beamlines. A correlation between Ag and Pd was found but not a clear evidence of alloying.
Received: 21 December 1998 / Received in final form: 19 March 1999 相似文献
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Abstract— The sequence specificity of photobinding to DNA of two tetrahydrobenzopsoralen derivatives has been investigated by testing the photoreactivity toward a number of self-complementary oligonucleotides. The thermodynamic constant for noncovalent binding to each DNA sequence was evaluated. The extent of photoreactivity was greatly dependent upon base composition. The two tetracyclic compounds show similar behavior in comparison to other bifunctional derivatives. Their overall rate constants were greatly enhanced in comparison to classical psoralens. However, their high efficiency of covalent binding is counterbalanced by low affinity for noncovalent interaction with DNA. 相似文献