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RISS 인기검색어
- 검색키워드
- 저자 : Cavallo, D.M. (검색결과 5 건)
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Accurate Free Vibration Analysis of Launcher Structures Using Refined 1D Models
Carrera, Erasmo,Zappino, Enrico,Cavallo, Tommaso The Korean Society for Aeronautical and Space Scie 2015 International Journal of Aeronautical and Space Sc Vol.16 No.2
This work uses different finite element approaches to the free vibration analysis of reinforced shell structures, and a simplified model of a typical launcher with two boosters is used as an example. The results obtained using a refined one-dimensional (1D) beam model are compared to those obtained with commercial finite element software. The 1D models that are used in the present work are based on the Carrera Unified Formulation (CUF), which assumes a variable kinematic displacement field over the cross-sections of the beam. Two different sets of polynomials that correspond to Taylor (TE) or Lagrange (LE) expansions were used. The analyses focused on three reinforced structures: a stiffened panel, a reinforced cylinder and the complete structure of the launcher. The frequencies and natural modes obtained using one-dimensional models are compared to those obtained from classical finite element analysis. The classical FE models were built using a beam-shell or solid elements, and the results indicate that the refined beam models can in fact be used to investigate the behavior of very complex reinforced structures. These models can predict the shell-like modes that are typical of thin-walled structures that cannot be detected using classical beam models. The refined 1D models used in the present work provide results that are as accurate as those from solid FE models, but the 1D models have a much lower computational cost.
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Cristina Nencini,Gian Gabriele Franchi,Federica Cavallo,Lucia Micheli 한국식품영양과학회 2010 Journal of medicinal food Vol.13 No.2
This study investigated the protective effect of Allium neapolitanum Cyr., a spontaneous species of the Italian flora, compared with garlic (Allium sativum L.) on liver injury induced by ethanol in rats. Male albino Wistar rats were orally treated with fresh Allium homogenates (leaves or bulbs, 250mg/kg) daily for 5 days, whereas controls received vehicle only. At the end of the experimental 5-day period, the animals received an acute ethanol dose (6mL/kg, i.p.) 2 hours before the last Allium administration and were sacrificed 6 hours after ethanol administration. The activities of catalase (CAT), superoxide dismutase (SOD), and glutathione reductase (GR) and the levels of malondialdehyde (MDA), ascorbic acid (AA), and reduced (GSH) and oxidized glutathione in liver tissue were determined. Administration of both Allium species for 5 days (leaves or bulbs) led to no statistical variation of nonenzymatic parameters versus the control group; otherwise Allium treatment caused an increase of GSH and AA levels compared with the ethanol group and a diminution of MDA levels, showing in addition that A. neapolitanum bulb had the best protective effect. Regarding to enzymatic parameters, GR and CAT activities were enhanced significantly compared with the ethanol group, whereas SOD activity showed a trend different from other parameters estimated. However, the treatment with both Allium species followed by acute ethanol administration reestablished the nonenzymatic parameters similar to control values and enhanced the activities of the enzymes measured. These results suggest that fresh Allium homogenates (leaves or bulbs) possess antioxidant properties and provide protection against ethanol-induced liver injury.
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Accurate Free Vibration Analysis of Launcher Structures Using Refined 1D Models
Erasmo Carrera,Enrico Zappino,Tommaso Cavallo 한국항공우주학회 2015 International Journal of Aeronautical and Space Sc Vol.16 No.2
This work uses different finite element approaches to the free vibration analysis of reinforced shell structures, and a simplified model of a typical launcher with two boosters is used as an example. The results obtained using a refined one-dimensional (1D) beam model are compared to those obtained with commercial finite element software. The 1D models that are used in the present work are based on the Carrera Unified Formulation (CUF), which assumes a variable kinematic displacement field over the cross-sections of the beam. Two different sets of polynomials that correspond to Taylor (TE) or Lagrange (LE) expansions were used. The analyses focused on three reinforced structures: a stiffened panel, a reinforced cylinder and the complete structure of the launcher. The frequencies and natural modes obtained using one-dimensional models are compared to those obtained from classical finite element analysis. The classical FE models were built using a beam-shell or solid elements, and the results indicate that the refined beam models can in fact be used to investigate the behavior of very complex reinforced structures. These models can predict the shell-like modes that are typical of thin-walled structures that cannot be detected using classical beam models. The refined 1D models used in the present work provide results that are as accurate as those from solid FE models, but the 1D models have a much lower computational cost.
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Surajit Pathak,Alessia Rosaria Grillo,Melania Scarpa,Paola Brun,Renata D’Incà,Laura Nai,Antara Banerjee,Donatella Cavallo,Luisa Barzon,Giorgio Palù,Giacomo Carlo Sturniolo,Andrea Buda,Ignazio Castagli 생화학분자생물학회 2015 Experimental and molecular medicine Vol.47 No.-
Abnormal levels of microRNA (miR)-155, which regulate inflammation and immune responses, have been demonstrated in the colonic mucosa of patients with inflammatory bowel diseases (IBD), although its role in disease pathophysiology is unknown. We investigated the role of miR-155 in the acquisition and maintenance of an activated phenotype by intestinal myofibroblasts (IMF), a key cell population contributing to mucosal damage in IBD. IMF were isolated from colonic biopsies of healthy controls, ulcerative colitis (UC) and Crohn’s disease (CD) patients. MiR-155 in IMF was quantified by quantitative reverse transcription-PCR in basal condition and following exposure to TNF-α, interleukin (IL)-1β, lipopolysaccharide (LPS) or TGF-β1. The effects of miR-155 mimic or inhibitor transfection on cytokine release and suppressor of cytokine signaling 1 (SOCS1) expression were assessed by enzyme-linked immunosorbent assay and western blot, respectively. Regulation of the target gene SOCS1 expression by miR-155 was assessed using luciferase reporter construct. We found that miR-155 was significantly upregulated in UC as compared with control- and CD-derived IMF. Moreover, TNF-α and LPS, but not TGF-β1 and IL-1β, significantly increased miR-155 expression in IMF. Ectopic expression of miR-155 in control IMF augmented cytokines release, whereas it downregulated SOCS1 expression. MiR-155 knockdown in UC-IMF reduced cytokine production and enhanced SOCS1 expression. Luciferase reporter assay demonstrated that miR-155 directly targets SOCS1. Moreover, silencing of SOCS1 in control IMF significantly increased IL-6 and IL-8 release. In all, our data suggest that inflammatory mediators induce miR-155 expression in IMF of patients with UC. By downregulating the expression of SOCS1, miR-155 wires IMF inflammatory phenotype.
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