888 research outputs found

    STUDIO NUMERICO DELL'EMODINAMICA IN PAZIENTI CON DISSECAZIONE AORTICA DI TIPO B

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    The development of type B aortic dissection (AoD) is caused by altered haemodynamic forces exerted on false and true lumina of dissected aorta. This work aims to study haemodynamic and morphological proprieties, which influence the progression or stability of type B AoD. Computational fluid-dynamic analyses were performed on three patients with type B AoD, whose two presented an aneurysm evolution and one presented no further complication connected with dissection. Blood flow features showed that the true lumen flow was laminar and uniform while false lumen flow lost the laminar characteristic with consequent vorticity formation. The entry point zone proximal to the aortic arch showed both high blood velocity and pressure connected with peaks of maximum WSS value. A negative pressure gradient between the false lumen entry and re-entry points was observed. This promotes the blood to flow towards the abdominal aorta reducing the risk of retrograde flow during systole. We concluded that fluid dynamics study of patients with type B AoD is a valid tool to identify the risk of aortic dissection progression as well as the formation of aortic dissection connected pathology

    Finite-element simulation of residual stress induced by split-sleeve cold-expansion process of holes

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    A three-dimensional finite-element simulation was conducted for a split-sleeve cold-expansion process in order to determine the residual stress field around an expanded hole. The commercial FEA software DEFORM-3D\u2122, a Lagrangian implicit code designed for metal forming processes, was used to model the cold-expansion process of a fastener hole. The results show a through-thickness residual stress field in good agreement with the analytical solution developed by Guo. Moreover, the simulation has highlighted the effect of the split sleeve and the plate thickness on the residual stress field. \ua9 2007 Elsevier B.V. All rights reserved

    Un nuovo caso di spontaneizzazione incipiente: Lagunaria patersonia (Andrews) G. Don (Malvaceae) in Sicilia

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    In questa nota si riporta l’incipiente processo di naturalizzazione in Sicilia di Lagunaria patersonia (Andrews) G. Don, un albero australiano sempreverde di media grandezza appartenente alla famiglia delle Malvaceae

    The impact of Pinus halepensis mill. afforestation on mediterranean spontaneous vegetation: do soil treatment and canopy cover matter?

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    We investigated central Mediterranean Pinus halepensis plantations under semi-arid climate in order to evaluate the combined effect of soil treatment and afforestation practices on spontaneous plant species composition, richness and evenness, and on the trend and speed of vegetation dynamics. Phytosociological relevés of three different plot typologies, i.e. (1) soil-treatment and plantation, (2) only soil-treatment, (3) no soil-treatment and no plantation, were compared by (a) multivariate analysis and (b) with reference to species richness and evenness. Moreover, in order to compare vegetation dynamics within the plantations with those ones ongoing in semi-natural garrigue communities, we compared life form and syntaxonomic spectra between phytosociological relevés taken at 8 years of distance. DCA showed that floristic species composition and similarity are influenced by the canopy cover of Pine trees as well as by soil-treatment practices. Although species richness and evenness are not clearly related to neither soil treatment nor Pine afforestation, canopy cover clearly plays a major role: in fact, the highest Ph cover rates correspond to the lowest values of understory species richness. This is true also if only species of biogeographical/conservation interest are considered. Regarding vegetation dynamics, sites with dense Pine canopy cover evolve much slower than the adjacent garrigue communities. The same factors invoqued to explain the patterns of floristic composition and similarity (i.e. allelopathy and competition for light, water and nutrients) may also explain the lowering of diversity of therophytes and the strong decline of the cover perfomed by both therophytes and hemicryptophytes underneath the canopy of dense Ph plantations. Thus, in sites where Ph cover exceeds about 80%, thinning is recommended not only in order to accelerate succession, but also to give a natural ‘shape’ to afforestations

    Acacia cyclops A. Cunn. ex G. Don (Leguminosae) in Italy: first cases of naturalization

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    Linosa (Pelagie Islands, Strait of Sicily). A decade later, this alien plant should no longer be considered as a casual, since a very intensive process of self-sown regeneration has been observed in some plantations on Lampedusa, the major island of the same Archipelago. The available literature suggests the need for careful monitoring of the ongoing invasion process, as A. cyclops has already shown a very invasive behaviour elsewhere within Mediterranean-type biomes due to its ability to withstand high environmental stresses. As migrating birds are suspected to have played an important role in facilitating the arrival of A. cyclops, further propagules are likely to reach the islands in the future. We recommend that new plantations of A. cyclops should be forbidden, but that extant naturalized populations should be managed instead of eradicating them. In fact, the effect of Acacia plantations warrants investigation at different scales in order to assess their impact on local plant-diversity and ecological succession processes

    An association of boswellia, betaine and myo-inositol (Eumastós) in the treatment of mammographic breast density. A randomized, double-blind study

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    Mammographic breast density is a recognized risk factor for breast cancer. The causes that lead to the proliferation of the glandular breast tissue and, therefore, to an increase of breast density are still unclear. However, a treatment strategy to reduce the mammary density may bring about very relevant clinical outcomes in breast cancer prevention. Myo-inositol is a six-fold alcohol of cyclohexane, has already been proved to modulate different pathways: inflammatory, metabolic, oxidative and endocrine processes, in a wide array of human diseases, including cancer and the genesis of mammary gland and breast diseases, like fibrosis, as well as metabolic and endocrine cues. Similarly, boswellic acid and betaine (three-methyl glycine) both inhibit inflammation and exert protective effects on breast physiology. Based on this scientific background, we hypothesized that a combination including, boswellic acid, betaine and myo-inositol would be able to reduce breast density working on different pathways.OBJECTIVE: Mammographic breast density is a recognized risk factor for breast cancer. The causes that lead to the proliferation of the glandular breast tissue and, therefore, to an increase of breast density are still unclear. However, a treatment strategy to reduce the mammary density may bring about very relevant clinical outcomes in breast cancer prevention. Myo-inositol is a six-fold alcohol of cyclohexane, has already been proved to modulate different pathways: inflammatory, metabolic, oxidative and endocrine processes, in a wide array of human diseases, including cancer and the genesis of mammary gland and breast diseases, like fibrosis, as well as metabolic and endocrine cues. Similarly, boswellic acid and betaine (threemethyl glycine) both inhibit inflammation and exert protective effects on breast physiology. Based on this scientific background, we hypothesized that a combinat ion including, boswellic acid, betaine and myo-inositol would be able to reduce breast density working on different pathways. PATIENTS AND METHODS: In this study, seventy-six premenopausal women were randomly assigned to the placebo and the experimental drug arms (Eumastós®) for six months. RESULTS: After 6 months of treatment, statistically significant difference between the two groups was recorded on the breast density reduction (60% vs. 9%), using mammographic as well as ultrasound examination. CONCLUSIONS: Preliminary data collected here with support the starting assumptions,that the association comprising boswellic acid, betaine and myo-inositol significantly reduces mammary density, providing the first evidence for a new and safe approach for the management of mammographic density treatment

    The recent spread of the invasive woody alien plant Melia azedarach L. (Meliaceae) in Sicily

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    This paper aims at reporting the ongoing process of naturalization of Melia azedarach L. in Sicily. In fact, over half a century after the first detection of spontaneous self-sown seedlings, an abrupt increase of naturalization cases has been recorded by the authors during the last twenty years. More in detail, M. azedarach successfully colonized many suburban lowland areas along the coasts of the island which are characterised by thermo-Mediterranean bioclimate. According to both field and literature data, a gradual spread of M. azedarach in the island can be expected, although it is not possible to predict the speed with which this will occur. Historical information on its introduction at global and local scales and on the traditional use of its seeds is provided, too

    Nicodemia madagascariensis (Lam.) R. Parker (Family Scrophulariaceae), a casual alien plant new to Italy

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    In this note the authors report the first case of naturalization of the Malagasy smoke bush within Italian territory. Along with a description of the abiotic and biotic characteristics of the invaded site, the current demographic and dynamic trends of the detected population by means of growth-ring analysis was also assessed. Moreover, an overview on the history of its introduction in Europe is provided, underlining the key role played by the Mediterranean cities with respect to the acclimatization and spread of alien tropical and subtropical plants. Due to its low frequency under cultivation, the Malagasy smoke bush should not behave as an invader in the future; on the other hand, its ability to cover and smother neighbouring trees in very short times, make its spread within the whole Mediterranean area worth regular monitoring

    Primi casi di naturalizzazione del noce nero (Juglans nigra L.) (Juglandaceae) in Sicilia

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    Il presente studio riporta i primi casi di naturalizzazione del noce nero in Sicilia. Il possibile ruolo giocato dagli animali disseminatori e dalle condizioni climatiche locali sono stati discussi
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