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31.
Alessandro D'Aprano Dorina Ines Donato Antonio Carrubba 《Journal of solution chemistry》1982,11(4):271-281
Conductance measurements of lithium picrate in solutions of water in n-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol and 3-methyl-1-butanol have been carried out at 25°C. Ionic association and conductance were found to change with water content and with the molecular structure of the alcohols (i.e. position of the OH group and degree of branching of the alkyl chain). These results indicate that both conductance and ion pair formation are not the consequence of the simple motion of ions in the electrical field as required by the continuum model. A more realistic approach, involving the internal structure of the solvent mixtures, has been considered. 相似文献
32.
Donato Bini Christian Cherubini Marco de Mattia Robert T. Jantzen 《General Relativity and Gravitation》2003,35(12):2249-2260
Accelerated circular orbits in the equatorial plane of the Taub-NUT spacetime are analyzed to investigate the effects of its gravitomagnetic monopole source. The effect of a small gravitomagnetic monopole on these orbits is compared to the corresponding orbits pushed slightly off the equatorial plane in the absence of the monopole. 相似文献
33.
34.
This paper is focused on the investigation of the Walrasian economic equilibrium problem involving utility functions. The
equilibrium problem is here reformulated by means of a quasi-variational inequality problem. Our goal is to give an existence
result without assuming strong monotonicity conditions. To this end, we make use of a perturbation procedure. In particular,
we will consider suitable perturbed utility functions whose gradient satisfies a strong monotonicity condition and whose associated
equilibrium problem admits a solution. Then, we will prove that the limit solution solves the unperturbed problem. We stress
out that our result allows us to consider a wide class of utility functions in which the Walrasian equilibrium problem may
be solved. 相似文献
35.
Donato Ercole Conte Abdelmaula Aboulaich Josette Olivier-Fourcade Christian Jordy 《Journal of solid state chemistry》2010,183(1):65-6650
A comparative study of two Sn-based composite materials as negative electrode for Li-ion accumulators is presented. The former SnB0.6P0.4O2.9 obtained by in-situ dispersion of SnO in an oxide matrix is shown to be an amorphous tin composite oxide (ATCO). The latter Sn0.72[BPO4]0.28 obtained by ex-situ dispersion of Sn in a borophosphate matrix consists of Sn particles embedded in a crystalline BPO4 matrix. The electrochemical responses of ATCO and Sn0.72[BPO4]0.28 composite in galvanostatic mode show reversible capacities of about 450 and 530 mAh g−1, respectively, with different irreversible capacities (60% and 29%). Analysis of these composite materials by 119Sn Mössbauer spectroscopy in transmission (TMS) and emission (CEMS) modes confirms that ATCO is an amorphous SnII composite oxide and shows that in the case of Sn0.72[BPO4]0.28, the surface of the tin clusters is mainly formed by SnII in an amorphous interface whereas the bulk of the clusters is mainly formed by Sn0. The determination of the recoilless free fractions f (Lamb-Mössbauer factors) leads to the effective fraction of both Sn0 and SnII species in such composites. The influence of chemical composition and especially of the surface-to-bulk tin species ratio on the electrochemical behaviour has been analysed for several Snx[BPO4]1−x composite materials (0.17<x<0.91). The cell using the compound Sn0.72[BPO4]0.28 as active material exhibits interesting electrochemical performances (reversible capacity of 500 mAh g−1 at C/5 rate). 相似文献
36.
Lysyl oxidases (LOXs) are enzymes that permit the covalent crosslinking of the component chains of collagen and elastin. These enzymes are present inside the nuclei of certain mammalian cells. Previous studies have proposed LOX binding to histone H1 in vitro, and histone H1 is known to control global chromatin compaction and mitotic chromosome architecture. Therefore, in the present study, we analyzed chromatin supraorganizational changes, mitotic abnormalities, mitotic indices and cell death ratios in COS-7 and NRK-49F cells with high and low lox expression levels, respectively. The objective was to support biochemical data of LOX-H1 interaction, by providing evidence of chromatin remodeling in vivo, under different lox expressions. Chromatin decondensation assessed by image analysis was observed in COS-7 cells with increased lox expression. This decondensation is suggested to be promoted by LOX actions on histone H1, which loosens the DNA-H1 complex. In NRK-49F cells transfected with antisense lox or subjected to treatment with beta-aminopropionitrile (BAPN), chromatin condensation and nuclear phenotypic variability were found, which may be due to reduced LOX-H1 interaction. When lox expression was increased in COS-7 cells, the frequency of irregular chromosome plates was not affected, but cell proliferation decreased and "cell death preceded by multinucleation" increased. In NRK-49F cells there was accelerated proliferation induced by transfection with the antisense lox, and confirmed when cells were treated with BAPN. Apoptosis increased in NRK-49F cells only with BAPN treatment whereas cell death preceded by multinucleation increased only after antisense lox transfection. The data presented herein regarding chromatin remodeling indirectly support the hypothesis that LOX binds to histone H1 in vivo. Cell proliferation in COS-7 and NRK-49F cells and cell death at least in COS-7 cells agree with predicted effects of LOX interference in these processes. 相似文献
37.
In this paper the question of finding infinitely many solutions to the problem −Δu+a(x)u=|u|p−2u, in RN, u∈H1(RN), is considered when N≥2, p∈(2,2N/(N−2)), and the potential a(x) is a positive function which is not required to enjoy symmetry properties. Assuming that a(x) satisfies a suitable “slow decay at infinity” condition and, moreover, that its graph has some “dips”, we prove that the problem admits either infinitely many nodal solutions or infinitely many constant sign solutions. The proof method is purely variational and allows to describe the shape of the solutions. 相似文献
38.
Riccardo Molle Donato Passaseo 《Calculus of Variations and Partial Differential Equations》2014,49(1-2):861-907
We present some multiplicity results concerning semilinear elliptic Dirichlet problems with jumping nonlinearities where the jumping condition involves a set of high eigenvalues not including the first one. Using a variational method we show that the number of solutions may be arbitrarily large provided the number of jumped eigenvalues is large enough. Indeed, we prove that for every positive integer $k$ there exists a positive integer $n(k)$ such that, if the number of jumped eigenvalues is greater than $n(k),$ then the problem has at least a solution which presents $k$ peaks. Moreover, we describe the asymptotic behaviour of the solutions as the number of jumped eigenvalues tends to infinity; in particular, we analyse some concentration phenomena of the peaks (near points or suitable manifolds), we describe the asymptotic profile of the rescaled peaks, etc $\ldots $ 相似文献
39.
Jussara de Araújo Gonçalves André Luis Dantas Ramos Layla L. L. Rocha Anderson Kurunczi Domingos Robson S. Monteiro José Sotolongo Peres Nelson C. Furtado Carlton A. Taft Donato A. G. Aranda 《Journal of Physical Organic Chemistry》2011,24(1):54-64
Biodiesel can be obtained from fatty acid raw materials through esterification. The reactivity of lauric, palmitic, stearic, oleic, and linoleic fatty acids with methanol using powdered niobic acid as a heterogeneous catalyst was investigated in this work, both experimentally (in a batch reactor) and theoretically. A 23 experimental design was used, with methanol/fatty acid molar ratio, catalyst concentration, and temperature as main factors. An empirical model demonstrated that temperature is the most important variable. Fourteen heterogeneous and 56 homogeneous‐like kinetic models were tested. A homogeneous‐like model considering zero order for all species and inhibition by water was the most adequate for experiments without catalyst. A homogeneous‐like model considering a second‐order reaction in relation to the fatty acid and no water inhibition was the most adequate for niobic acid catalyzed reaction. Molecular modeling confirmed the experimental results showing that the reactivity is directly related to the increase of unsaturated bonds and the reduction of carbon chain length. The polarity of the fatty acid is determinant in the reactivity. At the molecular level, reaction occurs between the HOMO orbital of methanol and LUMO orbitals of fatty acids and reactivity is higher when the energy difference between these orbitals is lower. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
40.
C. Bellecci G. E. M. L. Caputi F. De Donato P. Gaudio M. Valentini 《Il Nuovo Cimento C》1995,18(5):463-472
Summary In this report we introduce the infrared lidar-dial apparatus developed at the University of Calabria. It has been carried
out as a tool in the investigation of both the atmospheric pollution of trace gases and other atmospheric parameters as water
vapour. The general scheme of the station is described, as well as the performances of the home-made CO2 laser sources. Finally preliminary measurements of average concentration of ozone and water vapour over a range of about
3 km are presented and discussed in the report. 相似文献