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排序方式: 共有180条查询结果,搜索用时 31 毫秒
1.
F. de Candia L. Guadagno V. Vittoria 《Journal of Macromolecular Science: Physics》2013,52(3-4):347-356
Sorption and diffusion of dichloromethane vapor in the helical forms—that is, δ and γ—of syndiotactic polystyrene were investigated. The thermal transition from the δ to the γ form occurs through an intermediate mesomorphic form, also characterized by chains in helical conformation but lacking true crystalline order. The mesomorphic phase was found impermeable to the vapor at low activity, becoming permeable at higher activities. The presence of a mesomorphic phase, along with the crystalline and the amorphous forms, was suggested in the crystallized samples, too, and its fraction increases greatly going from the δ to the γ form. 相似文献
2.
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
3.
4.
Fabio Ferrini Daniele Fraternale Sabrina Donati Zeppa Giancarlo Verardo Andrea Gorassini Vittoria Carrabs Maria Cristina Albertini Piero Sestili 《Molecules (Basel, Switzerland)》2021,26(16)
Cannabis sativa L. has been used for a long time to obtain food, fiber, and as a medicinal and psychoactive plant. Today, the nutraceutical potential of C. sativa is being increasingly reappraised; however, C. sativa roots remain poorly studied, despite citations in the scientific literature. In this direction, we identified and quantified the presence of valuable bioactives (namely, β-sitosterol, stigmasterol, campesterol, friedelin, and epi-friedelanol) in the root extracts of C. sativa, a finding which might pave the way to the exploitation of the therapeutic potential of all parts of the C. sativa plant. To facilitate root harvesting and processing, aeroponic (AP) and aeroponic-elicited cultures (AEP) were established and compared to soil-cultivated plants (SP). Interestingly, considerably increased plant growth—particularly of the roots—and a significant increase (up to 20-fold in the case of β-sitosterol) in the total content of the aforementioned roots’ bioactive molecules were observed in AP and AEP. In conclusion, aeroponics, an easy, standardized, contaminant-free cultivation technique, facilitates the harvesting/processing of roots along with a greater production of their secondary bioactive metabolites, which could be utilized in the formulation of health-promoting and health-care products. 相似文献
5.
Riccardo Fazio Salvatore Iacono Alessandra Jannelli Giovanni Cavaccini Vittoria Pianese 《PAMM》2007,7(1):2150003-2150004
This is a mathematical and numerical study of liquid dynamics in a horizontal capillary. We present a two-liquids model which takes into account the effects of real phenomena like the outside flow dynamics. Moreover, we report on results obtained by an adaptive numerical method. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
6.
Vittoria Giunti 《Rendiconti del Circolo Matematico di Palermo》1940,63(1):65-90
7.
Vittoria de Nitto Personè 《Annals of Operations Research》2009,170(1):95-112
The aim of this paper is to improve the machine interference model with vacation to deal with more recent problems of the
communication area. To this scope the model is extended to include parallelism in the vacation station. The underlying Markov
process is analyzed and a state arrangement is found that yields an efficient matrix-analytic technique that substantially
lowers down the time- and space-complexity of standard methods. A numerical example of the method effectiveness is presented,
and an example of resource allocation is introduced that finds applications in the QoS management of wireless networks.
The author is thankful to the anonymous referees for the improvements their comments have earned to the quality of the presentation
and to the completeness of the paper. The author is thankful to Giuseppe Iazeolla, whose careful reading of the original draft
of this paper led to significant improvements in its overall quality. This work was partially supported by funds from the
FIRB project “Performance Evaluation of Complex Systems: Techniques Methodologies and Tools” and by the University of Roma
TorVergata project on High Performance ICT Platforms. 相似文献
8.
Assunta Esposito Pietro Filippo De Luca Vittoria Graziani Brigida DAbrosca Antonio Fiorentino Monica Scognamiglio 《Molecules (Basel, Switzerland)》2021,26(13)
Olea europaea germplasm is constituted by a huge number of cultivars, each one characterized by specific features. In this context, endemic cultivars evolved for a very long period in a precise local area, developing very specific traits. These characteristics include the production and accumulation of phytochemicals, many of which are also responsible for the nutraceutical value of the drupes and of the oils therefrom. With the aim of obtaining information on the phytochemical profile of drupes of autochthonous cultivars of Cilento, Vallo di Diano and Alburni National Park, a metabolomics-based study was carried out on 19 selected cultivars. Multivariate data analysis of 1H-NMR data and 2D NMR analyses allowed the rapid identification of metabolites that were qualitatively and/or quantitatively varying among the cultivars. This study allowed to identify the cultivars Racioppella, Guglia, Pizzulella, Oliva amara, and Racioppa as the richest in health-promoting phenolic compounds. Furthermore, it showed a significant variability among the different cultivars, suggesting the possibility of using metabolic fingerprinting approaches for cultivar differentiation, once that further studies aimed at assessing the influence of growing conditions and environmental factors on the chemical profiles of single cultivars are carried out. 相似文献
9.
V. Vittoria F. De Candia V. Capodanno A. Peterlin 《Journal of Polymer Science.Polymer Physics》1986,24(5):1009-1019
Quenched films of isotactic polypropylene were drawn at 110°C up to draw ratio λ = 18. The axial elastic modulus was measured as function of λ up to the highest achieved λ. The sorption and diffusion of CH2Cl2 at 25°C in the undrawn and drawn samples were studied. Exclusively transparent samples were used for the measurement of the density and transport properties. This reduces the maximum usable draw ratio to 15. The drawing process is inhomogeneous with neck propagation. In the neck the draw ratio increases by about 6. As a consequence of the increasing fraction of taut tie molecules the axial elastic modulus increases faster than the draw ratio. The transport parameters D, S, and λ indicate that the original lamellar morphology is completely transformed into the microfibrillar structure. 相似文献
10.
Ugo Azzena Giovanna DettoriMaria Vittoria Idini Luisa PisanoGrazia Sechi 《Tetrahedron》2003,59(40):7961-7966
Selective removal of the 4-methoxy group of 3,4,5-trimethoxystilbenes was performed under electron transfer conditions from Na metal in THF. Careful control of reaction conditions and quenching procedure allowed the synthesis of either (E)-3,5-dimethoxystilbenes or 3,5-dimethoxybibenzyls. 相似文献