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11.
Margherita Bernardeschi Patrizia Guidi Vittoria Scarcelli Giada Frenzilli Marco Nigro 《Analytical and bioanalytical chemistry》2010,396(2):619-623
Titanium dioxide is extensively used in a variety of products, including industrial materials and cosmetics. Studies mainly
performed on human cell lines and in vivo exposure on experimental animals have raised concern about the toxic effects of
ultrafine titanium dioxide; however, scarce information is available about its impact on aquatic life. The aim of this article
was to assess the genotoxic potential of TiO2 (anatase and rutile) on bottlenose dolphin leukocytes. Blood samples were obtained from four male and one female specimens
reared at the Adriatic SeaWorld “Oltremare” (Riccione, Italy). Leukocytes were isolated by the lyses procedure and in vitro
exposed to TiO2 in RPMI. Experimental solutions were sonicated immediately before dosing the cells. Three exposure times (4, 24 and 48 h)
and three doses (20, 50 and 100 μg/ml) were tested. Genotoxicity was detected by the single-cell gel electrophoresis (or comet
assay) at pH ≥ 13, assessing single/double-strand breaks and alkali-labile sites. Cytotoxicity was also detected by the Trypan
blue exclusion method. Results showed that both the crystalline forms of TiO2 were genotoxic for bottlenose dolphin leukocytes, with a statistically significant increase of DNA fragmentation after exposure
to 50 and 100 μg/ml for 24 and 48 h. Although preliminary, these are the first data regarding the genetic susceptibility of
toothed cetaceans toward an “emerging” pollutant, such as TiO2 particles. 相似文献
12.
Atutov S. N. Biancalana V. Burchianti A. Calabrese R. Corradi L. Dainelli A. Guidi V. Mai B. Marinelli C. Mariotti E. Moi L. Rossi A. Scansani E. Stancari G. Tomassetti L. Veronesi S. 《Hyperfine Interactions》2003,146(1-4):83-89
Hyperfine Interactions - Laser cooling and trapping of radioactive atoms represent the new frontier in atomic physics and a new powerful tool in nuclear physics. We are setting up at the... 相似文献
13.
V. T. Baranov S. Bellucci V. M. Biryukov G. I. Britvich C. Balasubramanian V. Guidi G. Giannini V. N. Zapolsky V. I. Kotov A. E. Kushnirenko V. A. Maisheev G. Martinelli E. Milan V. A. Pikalov V. I. Terekhov U. Uggerhoj V. N. Chepegin Yu. A. Chesnokov 《JETP Letters》2005,82(9):562-564
Radiation emitted by positrons moving in a periodically deformed crystal has been experimentally observed for the first time. Radiation spectra have been measured in a wide energy range. Experimental evidence has been obtained for an undulator peak in a radiation spectrum, which is qualitatively consistent with calculations. Crystalline undulators ensure an equivalent magnetic field of 1000 T and a period in the submillimeter range and can therefore be used to generate x-ray and gamma radiation that is a hundred times harder than radiation in usual undulators. 相似文献
14.
C. Buci P. R. Crippa G. M. de'Munari G. Guidi M. Manfredi R. Tedeschi A. Vecli P. Podini 《Hyperfine Interactions》1979,6(1-4):425-429
Muonium's reaction constants with DNA and its constituents in water solutions are reported and compared with the available data for hydrogen. The low frequency spectrum of the resulting muonic radicals in low magnetic fields is recognized.This work was supported by Consiglio Nazionale delle Ricerche, contract no 75.00862.02 and by CERN, Experimental Physycs Division. Data analysis performed at CINECA computation facilities. 相似文献
15.
Sacchetti A Guidi MC Arcangeletti E Nucara A Calvani P Piccinini M Marcelli A Postorino P 《Physical review letters》2006,96(3):035503
The first far-infrared absorption spectra of manganite samples at pressures P up to 10 GPa were obtained on La1-xCaxMnO3-y by use of synchrotron radiation. For x=0.25 and 0.20 (y=0), P promotes partial metallization at room temperature through a strong reduction of the insulating gap. An x=0.20 sample with y=0.08 does not show any charge delocalization effect up to 10 GPa. An Urbach-like model of disordered Jahn-Teller wells is shown to well fit the far-infrared band edge and allows one to obtain a reliable pressure dependence of the energy gap. 相似文献
16.
Carretta S Guidi T Santini P Amoretti G Pieper O Lake B van Slageren J El Hallak F Wernsdorfer W Mutka H Russina M Milios CJ Brechin EK 《Physical review letters》2008,100(15):157203
We study the spin dynamics in two variants of the high-anisotropy Mn6 nanomagnet by inelastic neutron scattering, magnetic resonance spectroscopy and magnetometry. We show that a giant-spin picture is completely inadequate for these systems and that excited S multiplets play a key role in determining the effective energy barrier for the magnetization reversal. Moreover, we demonstrate the occurrence of tunneling processes involving pair of states having different total spin. 相似文献
17.
We present the spectroscopy and photofragmentation dynamics of two isomeric protonated dipeptides, H+AlaTyr and H+TyrAla, in a cold ion trap. By a combination of infrared-ultraviolet double resonance experiments and density functional theory calculations, we establish the conformations present at low temperature. Interaction of the charge at the N-terminus with the carbonyl group and the tyrosine pi-cloud seems to be critical in stabilizing the low-energy conformations. H+AlaTyr has the flexibility to allow a stronger interaction between the charge and the aromatic ring than in H+TyrAla, and this interaction may be responsible for many of the differences we observe in the former: a significant redshift in the ultraviolet spectrum, a much larger photofragmentation yield, fewer stable conformations, and the absence of fragmentation in excited electronic states. 相似文献
18.
Orazio A. Attanasi Paolino Filippone Barbara Guidi Thomas Hippe Fabio Mantellini Lutz F. Tietze 《Tetrahedron letters》1999,40(52):827-9280
The first general protocol for the preparation of different polymer-bound 1,2-diaza-1,3-butadienes is reported. The utility of these supported reagents in the solid-phase synthesis of 4-triphenylphosphoranylidene-4,5-dihydropyrazol-5-ones by reaction with triphenylphosphine is presented. 相似文献
19.
I. V. Kirillin N. F. Shul’ga L. Bandiera V. Guidi A. Mazzolari 《The European Physical Journal C - Particles and Fields》2017,77(2):117
An investigation on stochastic deflection of high-energy negatively charged particles in a bent crystal was carried out. On the basis of analytical calculation and numerical simulation it was shown that there is a maximum angle at which most of the beam is deflected. The existence of a maximum, which is taken in the correspondence of the optimal radius of curvature, is a novelty with respect to the case of positively charged particles, for which the deflection angle can be freely increased by increasing the crystal length. This difference has to be ascribed to the stronger contribution of incoherent scattering affecting the dynamics of negative particles that move closer to atomic nuclei and electrons. We therefore identified the ideal parameters for the exploitation of axial confinement for negatively charged particle beam manipulation in future high-energy accelerators, e.g., ILC or muon colliders. 相似文献
20.
M. Riccò R. De Renzi G. Guidi C. Bucci P. Podini R. Tedeschi C. A. Scott 《Hyperfine Interactions》1986,32(1-4):757-762
Muonium adduct radicals have been studied in Norbornene and Bicyclooctene as a function of temperature from the liquid phase
down to the plastic phase and through the low temperature transition to a typical solid (brittle phase). The features of the
radical hyperfine spectra are discussed. The temperature coefficient for the hyperfine constants is 0.1 MHz/K for the NBE
exo isomer, 0.09 MHz/K for the BCOE radical and 0 for the NBE endo isomer. Regarding the dinamical features of the plastic
phase, the present data suggest the onset of anisotropy of the molecular reorientations prior to the transition to the brittle
phase. 相似文献