1,721,196 research outputs found
Electronic excitations and optical absorption of oligoacenes
No full textElectronic excitations and optical absorption of oligoacene
Testing the "strong" PAHs hypothesis. I. Profile invariance of electronic transitions of interstellar PAH cations
No full textThe so-called "strong'' Polycyclic Aromatic Hydrocarbons (PAHs) hypothesis postulates that isolated PAHs, which are thought to be the carriers of the Unidentified Infrared Bands, ought to be also responsible for a large number of Diffuse Interstellar Bands (DIBs). In this framework, the spectral profile of such DIBs should be due to unresolved rotational structure of vibronic absorption bands, the rotation of the molecule being by and large governed by the interaction with the interstellar radiation field. In this paper we quantitatively test the above hypothesis against the observational constraint of DIBs profile invariance, by using Monte-Carlo methods to model the photophysics of a prototypical interstellar PAH, namely the ovalene cation (C32H14+). Our results show that the predicted rotational band profiles are remarkably insensitive to both the ambient conditions and the assumed values of some poorly known parameters. The present model therefore offers a quantitative link between any given PAH and the observed DIB profiles, providing a valuable tool for molecular identification
ESTIMATION OF MECHANOCHEMICAL EFFECTS IN HETEROGENEOUS PROCESSES
Full text linkThe present work focuses on the comparison of mechanochemical and thermal processes on a kinetic basis, with the aim of pointing out the higher efficiency of mechanically activated reactions in solid-solid, solid-liquid and solid-gas systems. The comparison relies upon the correlation between processing parameters, reaction kinetics and local deformation events. The obtained
results are ascribed to the coupling of mechanical deformation with thermodynamic driving forces
Electronic excitations of oligoacenes: A time dependent density functional theory study
No full textOligoacenes in their crystalline state are increasingly used in the field of electronics and photonics. Following a recent systematic theoretical study of the five smallest oligoacene molecules (naphthalene, anthracene, tetracene, pentacene, and hexacene), we evaluate their one- and two-particle properties (electron affinities, ionisation energies, quasiparticle correction to the highest occupied molecular orbital-lowest unoccupied molecular orbital gap, exciton binding energy, electronic absorption), using different exchange-correlation functionals in the framework of Density Functional Theory (DFT) and Time Dependent DFT. The hybrid functional B3LYP is found to yield the best agreement with the available experimental data
Studi preliminari sulla dermotossicità da pelagia noctiluca nell'animale da esperimento
No full textGolgi-Cox impregnation and immunofluorescence. Simultaneous labeling in brain slices by confocal microscopy
No full textIMMUNOCYTOCHEMICAL DETECTION OF PSD-95, TH AND GOLGI-COX STAINED ELEMENTS: VISUALIZATION IN THE SAME SLICE. DOPAMINE
No full textSimultaneous Golgi-Cox and immunofluorescence labeling in brain slices by confocal microscopy
No full textProper visualization of neuronal elements is of fundamental importance in modern neuroscience. The Golgi-Cox method, since its discovery, has been usefully applied for qualitative and quantitative analysis of neuronal morphology. This method is a widely employed and provides detailed information about morphological characteristics of neurons, but none regarding their neurochemical features. Instead, immunohistochemical procedures, due to the ability of antibodies to bind specific antigens with high affinity, can provide a high degree of biochemical specificity but with less morphological detail if compared to Golgi-Cox impregnation. Hence, the combined use of these two approaches is highly desirable especially for confocal users that, can exploit the advantages of both methods simultaneously. Here we show an innovative procedure of perfusion and fixation of brain tissue, that allows, by applying Golgi-Cox impregnation and immunofluorescence in the same histological section, to obtain high-quality histological material, with a very simple and inexpensive method. This procedure is based on three simple fixation steps: 1) a paraformaldehyde perfusion followed by a standard post-fixation to stabilize the subsequent immunofluorescence reaction; 2) the classical Golgi-Cox impregnation and 3) an immunofluorescence reaction in previously impregnated material. This combination allows simultaneous visualization of i) structural details (Golgi-Cox impregnated neurons), ii) antigens' characterization, iii) morphological-neurochemical interactions between discrete neuronal elements iv) 3-D reconstruction and modeling v) and reduction of animals required. The method is easy to perform and can be reproducibly applied by small laboratories and expanded through the use of different antibodies. Overall, the method presented in this study offers an innovative and powerful approach to study the nervous system especially by using confocal microscopy
Electronic and Optical properties of Piramidines
No full textElectronic and Optical properties of Piramidine
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