583 research outputs found
Wave propagation in human long bones of arbitrary cross-section
No full textThe dynamic behavior of a dry long bone considered as a piezoelectric cylinder of crystal class 6 with arbitrary cross-section is presented. For the solution of the wave propagation problem we follow the procedure proposed in a previous work (D.I, Fotiadis, G. Foutsitzi, C.V. Massalas, Wave propogation modeling in human long bones, Acta Mechanica 137 (1-2) (1999) 65-82). The boundary conditions on the inner and outer lateral surface of the cylinder, which is of irregular shape, are satisfied by using the Fourier expansion collocation method. The obtained dispersion relation is solved numerically and results are presented for various cross-sections and geometrical parameters of the system. (C) 2000 Elsevier Science Ltd. All rights reserved.International Journal of Engineering Scienc
Optimal TNFS-secure pairings on elliptic curves with composite embedding degree
No full textIn this paper we present a comprehensive comparison between pairing-friendly elliptic curves, considering di erent curve forms and twists where possible. We de ne an additional measure of the e- ciency of a parametrized pairing-friendly family that takes into account the number eld sieve (NFS) attacks (unlike the -value). This measure includes an approximation of the security of the discrete logarithm problem in F pk , computed via the method of Barbulescu and Duquesne [4]. We compute the security of the families presented by Fotiadis and Konstantinou in [14], compute some new families, and compare the eciency of both of these with the (adjusted) BLS, KSS, and BN families, and with the new families of [20]. Finally, we recommend pairing-friendly elliptic curves for security levels 128 and 192
Optimal TNFS-secure pairings on elliptic curves with even embedding degree
No full textIn this paper we give a comprehensive comparison between pairing-friendly elliptic curves in Jacobi Quartic and Edwards form with quadratic, quartic, and sextic twists. Our comparison looks at the best choices to date for pairings on elliptic curves with even embedding degree on both G 1 ×G 2 \u3cbr/\u3eG1×G2\u3cbr/\u3e and G 2 ×G 1 \u3cbr/\u3eG2×G1\u3cbr/\u3e (these are the twisted Ate pairing and the optimal Ate pairing respectively). We apply this comparison to each of the nine possible 128-bit TNFS-secure families of elliptic curves computed by Fotiadis and Konstantinou; we compute the optimal choice for each family together with the fastest curve shape/pairing combination. Comparing the nine best choices from the nine families gives a optimal choice of elliptic curve, shape and pairing (given current knowledge of TNFS-secure families). We also present a proof-of-concept MAGMA implementation for each case. Additionally, we give the first analysis, to our knowledge, of the use of quadratic twists of both Jacobi Quartic and Edwards curves for pairings on G 2 ×G 1 \u3cbr/\u3eG2×G1\u3cbr/\u3e, and of the use of sextic twists on Jacobi Quartic curves on G 1 ×G 2 \u3cbr/\u3eG1×G2\u3cbr/\u3e
Organization of the G protein-coupled receptors rhodopsin and opsin in native membranes
No full textG protein-coupled receptors (GPCRs), which constitute the largest and structurally best conserved family of signaling molecules, are involved in virtually all physiological processes. Crystal structures are available only for the detergent-solubilized light receptor rhodopsin. In addition, this receptor is the only GPCR for which the presumed higher order oligomeric state in native membranes has been demonstrated (Fotiadis, D., Liang, Y., Filipek, S., Saperstein, D. A., Engel, A., and Palczewski, K. (2003) Nature 421, 127-128). Here, we have determined by atomic force microscopy the organization of rhodopsin in native membranes obtained from wild-type mouse photoreceptors and opsin isolated from photoreceptors of Rpe65-/- mutant mice, which do not produce the chromophore 11-cis-retinal. The higher order organization of rhodopsin was present irrespective of the support on which the membranes were adsorbed for imaging. Rhodopsin and opsin form structural dimers that are organized in paracrystalline arrays. The intradimeric contact is likely to involve helices IV and V, whereas contacts mainly between helices I and II and the cytoplasmic loop connecting helices V and VI facilitate the formation of rhodopsin dimer rows. Contacts between rows are on the extracellular side and involve helix I. This is the first semi-empirical model of a higher order structure of a GPCR in native membranes, and it has profound implications for the understanding of how this receptor interacts with partner proteins
Predicting lymphoma outcomes and risk factors in patients with primary Sjögren's Syndrome using gradient boosting tree ensembles
No full textHigh-resolution atomic force microscopy imaging of rhodopsin in rod outer segment disk membranes.
No full textAtomic force microscopy (AFM) is a powerful imaging technique that allows recording topographical information of membrane proteins under near-physiological conditions. Remarkable results have been obtained on membrane proteins that were reconstituted into lipid bilayers. High-resolution AFM imaging of native disk membranes from vertebrate rod outer segments has unveiled the higher-order oligomeric state of the G protein-coupled receptor rhodopsin, which is highly expressed in disk membranes. Based on AFM imaging, it has been demonstrated that rhodopsin assembles in rows of dimers and paracrystals and that the rhodopsin dimer is the fundamental building block of higher-order structures
Assessing the conservation status for the habitat 6210(*) Semi-natural dry grasslands and scrubland facies on calcareous substrates (Festuco-Brometalia)
No full textOne of the main goals of the protection and management of Natura 2000 habitat types is
the assessment of their conservation status. While some countries have already tested procedures to assess conservation status, many others, including Italy, still lack standard measures at the national level. The aim of our study was to address this lack of a national standard in Italy for habitat 6210(*) by adapting procedures used in other member states to
the Italian context. The dry grasslands of habitat 6210(*), determined by human activities, display very high species richness but are, at the same time, seriously threatened by current climatic trends and land-use changes. Although the conservation of this habitat is a priority, there is no policy regarding the conservation of such grasslands. On the basis of the parameters included in the Habitats Directive, we selected the indicators most suited to the assessment of conservation status. These indicators were inferred from floristic and vegetation data collected in 2010 and 2011. As structure parameters, we selected nongraminoid vs graminoid cover and shrub cover; as floristic and vegetation parameters, we
selected the occurrence and abundance of characteristic and abundant species, of species of conservation or biogeographic interest, and of weeds or invasive species. We identified three types of indicators, which represent a tool for conservation strategies aimed at grasslands included in habitat 6210(*)
The Po Plain, Adriatic and Eastern Mediterranean in the Late Bronze Age: fact, fancy and plausibility
No full textNo abstract available
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