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1,091 results on '"Martelli, S"'

204. In vitro replication of spontaneous fractures of the proximal human femur

Author

Cristofolini, L, Juszczyk, M, Martelli, S, Taddei, F, Viceconti, M, Cristofolini, L, Juszczyk, M, Martelli, S, Taddei, F, and Viceconti, M

Abstract

Spontaneous fractures (i.e. caused by sudden loading and muscle contraction, not by trauma) represent a significant percentage of proximal femur fractures. They are particularly relevant as may occur in elderly (osteoporotic) subjects, but also in relation to epiphyseal prostheses. Despite its clinical and legal relevance, this type of fracture has seldom been investigated. Studies concerning spontaneous fractures are based on a variety of loading scenarios. There is no evidence, nor consensus on the most relevant loading scenario. The aim of this work was to develop and validate an experimental method to replicate spontaneous fractures in vitro based on clinically relevant loading. Primary goals were: (i) repeatability and reproducibility, (ii) clinical relevance. A validated numerical model was used to identify the most critical loading scenario that can lead to head–neck fractures, and to determine if it is necessary to include muscle forces when the head–neck region is under investigation. The numerical model indicated that the most relevant loading scenario is when the resultant joint force is applied to the head at 8° from the diaphysis. Furthermore, it was found that it is not essential to include the muscles when investigating head–neck fractures. The experimental setup was consequently designed. The procedure included high-speed filming of the fracture event. Clinically relevant fracture modes were obtained on 10 cadaveric femurs. Failure load should be reported as a fraction of donor's body-weight to reduce variability. The proposed method can be used to investigate the reason and mechanism of failure of natural and operated proximal femurs.

Published
2007

205. Subject-specific finite element modelling of human bones: An in vitro evaluation of the overall accuracy

Author

Taddei, F, Cristofolini, L, Martelli, S., Gill, H S, Viceconti, M, Taddei, F, Cristofolini, L, Martelli, S., Gill, H S, and Viceconti, M

Abstract

The determination of the mechanical stresses induced in human bones is of great importance in both research and clinical practice. Since the stresses in bones cannot be measured non-invasively in vivo, the only way to estimate them is through subject-specific finite element modelling. Several methods exist for the automatic generation of these models from CT data, but before bringing them in the clinical practice it is necessary to assess their accuracy in the predictions of the bone stresses. Particular attention should be paid to those regions, like the epiphyseal and metaphyseal parts of long bones, where the automatic methods are typically less accurate. Aim of the present study was to implement a general procedure to automatically generate subject-specific finite element models of bones from CT data and estimate the accuracy of this general procedure by applying it to one real femur. This femur was tested in vitro under five different loading scenarios and the results of these tests were used to verify how the adoption of a simplified two-material homogeneous model would change the accuracy with respect to the density-based inhomogeneous one, with special attention paid to the epiphyseal and metaphyseal proximal regions of the bone. The results showed that the density-based inhomogeneous model predicts with a very good accuracy the measured stresses (R2=0.91, RMSE=8.6%, peak error=27%), while the two-material model was less accurate (R2=0.89, RMSE=9.6%, peak error=35%). The results showed that it is possible to automatically generate accurate finite element models of bones from CT data and that the strategy of material properties mapping has a significant influence on its accuracy.

Published
2006

233. A harmonised dataset of greenhouse gas emissions inventories from cities under the EU Covenant of Mayors initiative.

Author

Iancu, A., Martelli, S., Cerutti, A. K., Janssens-Maenhout, G., Melica, G., Rivas-Calvete, S., Kona, A., Zancanella, P., and Bertoldi, P.

Subjects
*GREENHOUSE gases, *EMISSIONS (Air pollution), *CLIMATE change, *CITIES & towns, *ENERGY consumption
Abstract

The realization of national climate change commitments, as agreed through international negotiations, requires local action. However, data is still insufficient to make accurate statements about the scale of urban emissions (UNHABITAT, 2011). The need of comparable emission inventories at city level, including smaller cities, is widely recognized to develop evidence-based policies accounting for the relation between emissions and institutional, socio-economic and demographic characteristics at city level. This paper presents a collection of harmonized greenhouse gases (GHG) emission inventories (the "CoM sample 2013") at municipal level directly computed by the cities and towns that participate in the EU Covenant of Mayors initiative. This is the mainstream European movement of local and regional authorities who voluntarily commit to reduce GHG emissions by 20% or more by 2020. The "CoM sample 2013" (http://edgar.jrc.ec.europa.eu/com/data/index.php? SECURE=123, doi:10.2904/EDGARcom2013) has been carefully checked to ensure its internal consistency and its congruity with respect to internationally accepted guide values for emission factors. Overall, it provides valuable data for the analysis of the heterogeneity of final energy consumption and greenhouse gas emissions of cities. [ABSTRACT FROM AUTHOR]

Published
2015
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235. On the growth of LiF films by Pulsed Laser Deposition

Author

Perea, Ángel, Gonzalo, J., Afonso, Carmen N., Martelli, S., Montereali, R.M., Perea, Ángel, Gonzalo, J., Afonso, Carmen N., Martelli, S., and Montereali, R.M.

Abstract

The production of Lithium fluoride (LiF) films by Pulsed Laser Deposition is reported for the first time. The influence of several deposition parameters such as the laser energy density, the presence of a gas pressure (10-1 mbar of He) and the substrate temperature on the film quality is studied by using in-situ reflectivity measurements, Scanning Electron Microscopy and X-ray diffraction. Films deposited in vacuum are polycrystalline and fully textured along the (100) orientation, whereas those grown in He pressure present a more complicated structure. Films are generally rough, the roughness decreasing as the substrate temperature increases or the laser energy density decreases. The origin of this roughness is discussed in terms of the ablation mechanism taking place at the target. © 1999 Elsevier Science B.V. All rights reserved.

Published
1999

238. REAL-TIME PCR PER LA RICERCA DI HCV RNA NEL PLASMA.

Author

Cerutti, F., primary, Allice, T., additional, Gabella, S., additional, Pittaluga, F., additional, Varetto, S., additional, Giliberto, G., additional, Martelli, S., additional, Smedile, A., additional, Ghisetti, V., additional, and Marchiaro, G., additional

Published
2006
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242. TIMING LIVER TX IN ALF WITH KCH COMBINATIONS AND MARS

Author

Novelli, G, primary, Rossi, M, additional, Pugliese, F, additional, Iappelli, M, additional, Novelli, L, additional, Antonellis, F, additional, di Folco, G, additional, Martelli, S, additional, Ferretti, G, additional, and Berloco, P, additional

Published
2006
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