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61.
Rocco Angelone Dr. Francesco Ciardelli Prof. Arturo Colligiani Prof. Francesco Greco Dr. Paolo Masi Prof. Annalisa Romano Dr. Giacomo Ruggeri Prof. 《Chemphyschem》2010,11(2):460-465
A derivative of 2‐methylindole, 3‐[2‐(4‐nitrophenyl)ethenyl]‐1‐allyl‐2‐methylindole, NPEMI‐A, is studied for its photoconductivity and photorefractivity behaviour. Its blends with the organic polymer poly‐(2,3‐dimethyl‐N‐vinylindole), PVDMI, are also investigated. Due to the expected and devised mutual solubility of the two components of the blends, it is possible to carry out measurements with the weight percent of the chromophore NPEMI‐A changing from zero to 100. Films were produced by a squeezing process between two ITO‐covered glass sheets. No opacity phenomena, that are so common for many other organic blends due to the segregation of the dissolved chromophore, are observed. The photorefractive optical gain Γ2 is obtained as a function of the chromophore content. Differential scanning calorimetry measurements (DSC) are also carried out to obtain the whole change of the glass transition temperature Tg as a function of the amount of chromophore contained in the blends. From the experimental trend of Tg a meaningful quantitative estimate of the value of the electrostatic interactions acting in the studied blends, is obtained. The importance of the value of Tg, and of the electrostatic interactions, in determining the extent of the photorefractivity is clearly evident. The results are compared for NPEMI‐A (Γ2=210 cm?1) and for NPEMI‐E (Γ2 ≈ 2000 cm?1) that has a N‐2‐ethylhexyl group instead of a N‐allyl group. The Pockels and Kerr contributions and—for the first time—a “collaborative effect” of the photorefractivity of NPEMI‐A are distinguished and quantitatively evaluated. 相似文献
62.
Cali F Ragalmuto A Chiavetta V Calabrese G Fichera M Vinci M Ruggeri G Schinocca P Sturnio M Romano S Romano V Elia M 《Experimental & molecular medicine》2010,42(12):842-848
Angelman syndrome (AS) is a severe neurobehavioural disorder caused by failure of expression of the maternal copy of the imprinted domain located on 15q11-q13. There are different mechanisms leading to AS: maternal microdeletion, uniparental disomy, defects in a putative imprinting centre, mutations of the E3 ubiquitin protein ligase (UBE3A) gene. However, some of suspected cases of AS are still scored negative to all the latter mutations. Recently, it has been shown that a proportion of negative cases bear large deletions overlapping one or more exons of the UBE3A gene. These deletions are difficult to detect by conventional gene-scanning methods due to the masking effect by the non-deleted allele. In this study, we have used for the first time multiplex ligation-dependent probe amplification (MLPA) and comparative multiplex dosage analysis (CMDA) to search for large deletions affecting the UBE3A gene. Using this approach, we identified a novel causative deletion involving exon 8 in an affected sibling. Based on our results, we propose the use of MLPA as a fast, accurate and inexpensive test to detect large deletions in the UBE3A gene in a small but significant percentage of AS patients. 相似文献
63.
Dragonetti R Ianniello C Romano RA 《The Journal of the Acoustical Society of America》2011,129(2):753-764
Air-flow resistivity is a main parameter governing the acoustic behavior of porous materials for sound absorption. The international standard ISO 9053 specifies two different methods to measure the air-flow resistivity, namely a steady-state air-flow method and an alternating air-flow method. The latter is realized by the measurement of the sound pressure at 2 Hz in a small rigid volume closed partially by the test sample. This cavity is excited with a known volume-velocity sound source implemented often with a motor-driven piston oscillating with prescribed area and displacement magnitude. Measurements at 2 Hz require special instrumentation and care. The authors suggest an alternating air-flow method based on the ratio of sound pressures measured at frequencies higher than 2 Hz inside two cavities coupled through a conventional loudspeaker. The basic method showed that the imaginary part of the sound pressure ratio is useful for the evaluation of the air-flow resistance. Criteria are discussed about the choice of a frequency range suitable to perform simplified calculations with respect to the basic method. These criteria depend on the sample thickness, its nonacoustic parameters, and the measurement apparatus as well. The proposed measurement method was tested successfully with various types of acoustic materials. 相似文献
64.
Stefano Romano 《Mathematische Annalen》2014,360(3-4):715-751
A Frobenius manifold has tri-Hamiltonian structure if it is even-dimensional and its spectrum is maximally degenerate. We study the case of the lowest nontrivial dimension \(n=4\) and show that, under the assumption of semisimplicity, the corresponding isomonodromic Fuchsian system is described by the Painlevé \(\hbox {VI}\mu \) equation. Since the solutions of this equation are known to parametrize semisimple Frobenius manifolds of dimension \(n=3\) , this leads to an explicit procedure mapping 3-dimensional Frobenius structures of 4-dimensional ones, and giving all tri-Hamiltonian structures in four dimensions. We illustrate the construction by computing two examples in the framework of Frobenius structures on Hurwitz spaces. 相似文献
65.
Maria D. Ruiz-Medina Rosa M. Espejo Elvira Romano 《Advances in Data Analysis and Classification》2014,8(3):257-285
This paper proposes a spatial functional formulation of the normal mixed effect model for the statistical classification of spatially dependent Gaussian curves, in both parametric and state space model frameworks. Fixed effect parameters are represented in terms of a functional multiple regression model whose regression operators can change in space. Local spatial homogeneity of these operators is measured in terms of their Hilbert–Schmidt distances, leading to the classification of fixed effect curves in different groups. Assuming that the Gaussian random effect curves obey a spatial autoregressive dynamics of order one [SARH(1) dynamics], a second functional classification criterion is proposed in order to detect local spatially homogeneous patterns in the mean quadratic functional variation of Gaussian random effect curve increments. Finally, the two criteria are combined to detect local spatially homogeneous patterns in the regression operators and in the functional mean quadratic variation, under a state space approach. A real data example in the financial context is analyzed as an illustration. 相似文献
66.
R. G. Pizzone C. Spitaleri A. M. Mukhamedzhanov L. D. Blokhintsev C. A. Bertulani B. F. Irgaziev M. La Cognata L. Lamia S. Romano 《Few-Body Systems》2011,50(1-4):319-321
The widths of the spectator momentum distributions in several nuclei, which have been used as Trojan Horses, have been obtained as a function of the transferred momentum. Applications of Trojan Horse method will also be discussed. 相似文献
67.
Agricultural vehicle operators are exposed to high levels of whole body vibrations (WBVs) which are related, above all, to surface irregularities, forward speed and vehicle setting. European Parliament Directive 2002/44/EEC sets the minimum requirements for the protection of workers from risks to their health and safety due to exposure to mechanical vibrations, and it is therefore of utmost to investigate any source of vibration during agricultural works and any machine-related transmission element. Tractor tires play a key role in damping vibrations; their response varies according to the tractor mass and tire inflation pressure and, during transport, they have to be taken into account at different forward speeds. The eccentricity of the tire is one of the factors thus influences the amplitude of the solicitations acting on the tire. This study was aimed at evaluating the influence of the “tire eccentricity” parameter on driver comfort and at introducing a test method for its assessment for validation purposes. 相似文献
68.
Dario Romano Efren Alberto Andablo‐Reyes Sara Ronca Sanjay Rastogi 《Journal of polymer science. Part A, Polymer chemistry》2013,51(7):1630-1635
The use of a hindered phenol to trap free trimethylaluminum (TMA) in methylaluminoxane (MAO) solutions has been reported to improve the performance of single‐site, homogeneous catalysts for olefin polymerization. In the present study, with the help of rheological analyses, we have investigated and compared the molecular weight, molecular weight distribution and entanglement density of ultrahigh molecular weight polyethylene synthesized with a single‐site catalyst activated by MAO and phenol‐modified MAO. While the number average molecular weight (Mn) of the obtained polymers remains the same for both activations, a higher yield and a higher entanglement density are found in the initial stages of polymerization on using phenol‐modified MAO as the cocatalyst. These results suggest that on using the phenol‐modified MAO as activator, a higher number of active sites are obtained. Surprisingly in the presence of untreated MAO, a tail in the higher molecular mass region is produced. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 相似文献
69.
70.
The oxidation of perfluorobutene‐2 (C4F8) initiated by trifluoromethyl hypofluorite (CF3OF) in presence of O2 has been studied at 323.1, 332.6, 342.5, and 352.0 K, using a conventional static system. The initial pressure of CF3OF was varied between 4.8 and 23.6 Torr, that of C4F8 between 48.7 and 302.4 Torr, and that of O2 between 51.5 and 270.4 Torr. Several runs were made in presence of 325.5–451.2 Torr of N2. The main products were COF2, CF3C(O)F, and CF3OC(O)F. Small amounts of compound containing ? CF(CF3)? O? C(O)CF3 group were also formed, as detected by 13C NMR spectroscopy. The oxidation is a homogeneous short‐chain reaction, attaining, at the pressure of O2 used, the pseudo‐zero‐order condition with respect to O2 as reactant. The reaction is independent of the total pressure. Its basic steps are as follows: the thermal generation of CF3O? radicals by the abstraction of fluorine atom of CF3OF by C4F8, the addition of CF3O? to the alkene, the formation of perfluoroalkoxy radicals RO? in presence of O2, and the decomposition of these radicals via the C? C bond scission, giving products containing ? C(O)F end group and reforming RO? and CF3O? radicals. The mechanism consistent with experimental results is postulated. © 2003 Wiley Periodicals, Inc. Int J Chem Kinet 35: 532–541, 2003 相似文献