8,850 research outputs found

    Mechanical Systems: Symmetry and Reduction

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    Reduction theory is concerned with mechanical systems with symmetries. It constructs a lower dimensional reduced space in which associated conservation laws are taken out and symmetries are \factored out" and studies the relation between the dynamics of the given system with the dynamics on the reduced space. This subject is important in many areas, such as stability of relative equilibria, geometric phases and integrable systems

    Linomide blocks angiogenesis by breast carcinoma vascular endothelial growth factor transfectants.

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    The blocking of angiogenesis provides a novel therapeutic target to inhibit tumour spreading. In this study, we investigated the effect of linomide on angiogenesis induced in vivo by highly angiogenic breast carcinoma cells. The rabbit cornea was used to assess neovascular growth in the absence of a tumour mass. MCF-7 cells stably transfected with the cDNA encoding for vascular endothelial growth factor 121 (VEGF121) (V12 clone) were used to elicit a potent VEGF-dependent corneal angiogenesis. After tumour cell implant, albino rabbits received 100 mg kg(-1) day(-1) linomide for 5 consecutive days. Daily observation of neovascular progression indicated that linomide blocked angiogenesis. The antiangiogenic effect of linomide was apparent within 48 h from the beginning of the treatment and was both angiosuppressive and angiostatic. The block of neovascular growth lasted over 10 days from treatment suspension, and preformed vessels, which had regressed, remained dormant, suggesting the persistence of unfavourable conditions for capillary progression. Linomide (50-200 microg ml[-1]) was not cytotoxic in vitro on resting capillary endothelial cells but blocked endothelial cell replication induced by VEGF. Our data indicate that linomide can efficiently and persistently block VEGF-dependent angiogenesis in vivo in the absence of a growing tumour mass. These data suggest that linomide could be a chemopreventive drug in breast cancer patients and a valuable tool in clinical settings in which metastatic spreading occurs in the absence of a detectable tumour mass

    The Perugia (Italy) earthquake of April 29,1984: a seismic survey

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    International audienceA field study after the Perugia earthquake of 29 April 1984 provided more than 300 well-recorded events concentrated within two parallel clusters separated by 2 km and trending along the Apenninic direction. The length of the aftershock area is 14 km, focal depths being shallower than 8 km. Relocation of the main event places the epicenter at the southern end of the aftershock zone, suggesting a rupture propagation from SE to NW. Most focal mechanisms are consistent with normal faulting. The spatial distribution of seismicity suggests that the Gubbio normal fault was activated during the main shock. This earthquake, together with the Norcia 1979 and the Abruzzi 1984 shocks, is typical of the extension in the high Apennines generated by the flexure of the mountain chain in response to regional compression. The Parma 1983 event, a thrust, belongs to the compres- sion zone at the eastern flank of the chain. These results are consistent with the EW continental collision along the Apennines

    Comprehensive Review on the Dynamic and Seismic Behavior of Flat-Bottom Cylindrical Silos Filled With Granular Material

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    The seismic design of industrial flat-bottom ground-supported silos filled with granular material still presents several challenges to be addressed. They are related to the main aspects which differentiate silo structures containing granular material from other civil structural typologies: 1) the relatively low silo structure mass as compared to the ensiled content mass; 2) the granular nature of the ensiled material. Indeed, the internal actions in the structural members are governed by the complex dynamic interactions along the interfaces between granular content and silo wall or base, or even the internal interaction between particles. More in detail, even though the scientific interest in such complex interactions dates back to the middle of the 19th century, several issues are still unclear such as the dependency of the fundamental dynamic properties (period of vibration and damping ratio) on the characteristics of the dynamic excitation (intensity, frequency content, duration) or the amount of ensiled material mass activated during a seismic excitation and provoking extra pressures on the wall (effective mass). Therefore, most of current seismic code provisions for silos are grounded on rather approximate and simplified assumptions leading to often over-conservative evaluations. The present paper intends to provide a comprehensive summary of the mainly acknowledged experimental and theoretical advances in the dynamic and seismic behavior of silos, supporting the potential researcher in the field to understand the real differences between the code assumptions and recommendations and the actual conditions, as well as illustrating the open issues to be still further investigated

    Atypical mature T-cell neoplasms: The relevance of the role of flow cytometry

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    Lymphoproliferative disorders are a heterogeneous group of malignant clonal proliferations of lymphocytes whose diagnosis remains challenging, despite diagnostic criteria are now well established, due to their heterogeneity in clinical presentation and immunophenotypic profile. Lymphoid T-cell disorders are more rarely seen than B-cell entities and more difficult to diagnose for the absence of a specific immunophenotypic signature. Flow cytometry is a useful tool in diagnosing T-cell lymphoproliferative disorders since it is not only able to better characterize T-cell neoplasms but also to resolve some very complicated cases, in particular those in which a small size population of neoplastic cells is available for the analysis. Here, we report three patients with mature T-cell neoplasms with atypical clinical and biological features in which analysis of peripheral blood and bone marrow specimens by means of multicolor flow cytometry was very useful to identify and characterize three rare T-cell lymphoproliferative disorders, such as angioimmunoblastic T-cell lymphoma, peripheral T-cell lymphoma not otherwise specified and T-cell prolym-phocytic leukemia. The aim of this case series report is not only to describe three rare cases of lymphoproliferative neoplasms but also to raise awareness that a fast, highly sensitive, and reproducible procedure, such as flow cytometry immunophenotyping, can have a determinant diagnostic role in these patients

    Transcribed ultraconserved noncoding RNAs (T-UCR) are involved in Barrett's esophagus carcinogenesis.

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    Barretts esophagus (BE) involves a metaplastic replacement of native esophageal squamous epithelium (Sq) by columnar-intestinalized mucosa, and it is the main risk factor for Barrett-related adenocarcinoma (BAc). Ultra-conserved regions (UCRs) are a class non-coding sequences that are conserved in humans, mice and rats. More than 90% of UCRs are transcribed (T-UCRs) in normal tissues, and are altered at transcriptional level in tumorigenesis. To identify the T-UCR profiles that are dysregulated in Barretts mucosa transformation, microarray analysis was performed on a discovery set of 51 macro-dissected samples obtained from 14 long-segment BE patients. Results were validated in an independent series of esophageal biopsy/surgery specimens and in two murine models of Barretts esophagus (i.e. esophagogastric-duodenal anastomosis). Progression from normal to BE to adenocarcinoma was each associated with specific and mutually exclusive T-UCR signatures that included up-regulation of uc.58-, uc.202-, uc.207-, and uc.223- and down-regulation of uc.214+. A 9 T-UCR signature characterized BE versus Sq (with the down-regulation of uc.161-, uc.165-, and uc.327-, and the up-regulation of uc.153-, uc.158-, uc.206-, uc.274-, uc.472-, and uc.473-). Analogous BE-specific T-UCR profiles were shared by human and murine lesions. This study is the first demonstration of a role for T-UCRs in the transformation of Barretts mucosa

    Age- and sex-related variations in platelet count in Italy: a proposal of reference ranges based on 40987 subjects' data

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    BACKGROUND AND OBJECTIVES: Although several studies demonstrated that platelet count is higher in women, decreases with age, and is influenced by genetic background, most clinical laboratories still use the reference interval 150-400×10(9) platelets/L for all subjects. The present study was to identify age- and sex-specific reference intervals for platelet count. METHODS: We analysed electronic records of subjects enrolled in three population-based studies that investigated inhabitants of seven Italian areas including six geographic isolates. After exclusion of patients with malignancies, liver diseases, or inherited thrombocytopenias, which could affect platelet count, reference intervals were estimated from 40,987 subjects with the non parametric method computing the 2.5° and 97.5° percentiles. RESULTS: Platelet count was similar in men and women until the age of 14, but subsequently women had steadily more platelets than men. The number of platelets decreases quickly in childhood, stabilizes in adulthood, and further decreases in oldness. The final result of this phenomenon is that platelet count in old age was reduced by 35% in men and by 25% in women compared with early infancy. Based on these findings, we estimated reference intervals for platelet count ×10(9)/L in children (176-452), adult men (141-362), adult women (156-405), old men (122-350) and, old women (140-379). Moreover, we calculated an extended reference interval that takes into account the differences in platelet count observed in different geographic areas. CONCLUSIONS: The age-, sex-, and origin-related variability of platelet count is very wide, and the patient-adapted reference intervals we propose change the thresholds for diagnosing both thrombocytopenia and thrombocytosis in Italy

    Integration of ARGO trajectories in the Mediterranean Forecasting System and impact on the regional analysis of the Western Mediterranean circulation

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    The impact of ARGO trajectory assimilation on the quality of ocean analyses is studied by means of an operational oceanographic model implemented in the Mediterranean Sea and a 3D-var assimilation scheme. For the first time, both ARGO trajectories and vertical profiles together with satellite data are assimilated to produce analyses for short term forecasts. The study period covers three months during winter 2005 when four ARGO trajectories were present in the northwestern Mediterranean Sea. It is shown that their integration is consistent with the other components of the assimilation system, and it contributes to refine the model error structure with new information on horizontal pressure gradients. So the analysis benefits of a more accurate description of the boundary currents and their instabilities that drive the mesoscale activity of regional circulations. As a consequence, the trajectory assimilation remotely and significantly influences the basin scale circulation. Changes can be depicted by intermediate water mass redistributions, mesoscale eddy relocations or net transports modulations. These impacts are detailed and assessed considering historical and contemporary datasets. The obtained qualitative and quantitative agreements motivate the integration of ARGO trajectories in the operational Mediterranean Forecasting System
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