Multi-view 3D retrieval using silhouette intersection and multi-scale contour representation

We describe in this paper two methods for 3D shape indexing and retrieval that we apply on two data collections of the SHREC - SHape Retrieval Contest 2007: Watertight models and 3D CAD models. Both methods are based on a set of 2D multi-views after a pose and scale normalization of the models using PCA and the enclosing sphere. In all views we extract the models silhouettes and compare them pairwise. In the first method the similitude measure is obtained by integrating on the pairs of views the difference between the areas of the silhouettes union and the silhouettes intersection. In the second method we consider the external contour of the silhouettes, extract their convexities and concavities at different scale levels and build a multiscale representation. The pairs of contours are then compared by elastic matching achieved by using dynamic programming. Comparisons of the two methods are shown with their respective strengths and weaknesses

Fuel Tank Design Optimization in Extrusion Blow Moulding

Peer reviewed: YesNRC publication: Ye

Preform Shape and Operating Condition Optimization for the Stretch Blow Molding Process

Peer reviewed: YesNRC publication: Ye

Antigenic Properties of Recombinant Envelope Glycoproteins Derived from T-Cell-Line-Adapted Isolates or Primary Human Immunodeficiency Virus Isolates and Their Relationship to Immunogenicity

AbstractThe native envelope glycoproteins of primary HIV-1 virions have weaker antigenicity than do T-cell laboratory-adapted (TCLA) viruses. These antigenic properties require further evaluation if recombinant envelope glycoproteins are produced as part of a vaccine strategy. In this study, we compared the antigenicity of recombinant envelope glycoproteins derived from three primary isolates (PI) (HIV-1BX08, HIV-1CHA, and HIV-1133) and two TCLA viruses (HIV-1HXB2 and HIV-1MN) produced using the Semliki Forest virus (SFV) system. This analysis was performed by radioimmunoprecipitation assays and flow cytometry. The results suggest that the SFV produces envelope glycoproteins with features in common with the envelopes found in naturally occurring virions. In particular, the PI envelopes had weak heterogeneous antigenic properties. However, the cytometric analysis also showed that there was less envelope glycoprotein on the cell surface for the PI envelopes than for those of TCLA viruses, suggesting differences in their intracellular trafficking. The immunogenic properties of the various envelope glycoproteins were evaluated in mice using recombinant SFV particles as vaccine vectors. The PI envelopes were less immunogenic than the TCLA envelopes, probably due to both their low antigenicity and cell surface expression level. Thus, it may be difficult to design an effective vaccine based on native recombinant PI envelopes

Phenotypic plasticity in habitat use and growth of the European eel (Anguilla anguilla) in transitional waters in the Mediterranean area

Lagoons and estuaries are transitional waters (TW), saline in character but substantially influenced by freshwater (FW) flows and the most productive habitat after upwelling areas. The European eel, Anguilla anguilla, is a typical inhabitant of these habitats and a target of important lagoon fisheries since ancient times. Notwithstanding this, in the Mediterranean region, where the numerous coastal lagoons are the most eligible habitat for this species, eel habitat use and growth, which display a high inter-individual variability, are poorly studied. To gain knowledge about the migratory behaviour and the relative growth history of this species in TW in the Mediterranean area, the otolith Sr/Ca ratios of 56 individuals were analysed. The study sampling sites were two typical coastal lagoon environments, Caprolace lagoon and Lesina lagoon, located, respectively on the Tyrrhenian and the Adriatic coast of Italy, and the Tiber River (TR) estuary, in Central Italy. Otolith Sr/Ca profiles revealed that in all the sites, the resident contingent is substantial, while the proportion of nomad eels, or habitat inter-shifter, was different among sites. Mean annual grow rate of resident eels is higher in productive environments (TR and lagoon of Lesina), while in Caprolace lagoon, an oligotrophic lagoon, resident eels grow slower. The observed patterns of habitat use and growth seem linked to local ecological conditions: facultative movements of eels with a nomadic behaviour seem affected by food availability rather than by the salinity gradient. This consideration supports the hypothesis that the facultative catadromous migration of European eel in Mediterranean TW, and the trophic shifts that this species exhibits, depend primarily on the productivity of the environment rather than on its salinity gradient

Tests of the Equivalence Principle with Neutral Kaons

We test the Principle of Equivalence for particles and antiparticles, using CPLEAR data on tagged K0 and K0bar decays into pi^+ pi^-. For the first time, we search for possible annual, monthly and diurnal modulations of the observables |eta_{+-}| and phi_{+-}, that could be correlated with variations in astrophysical potentials. Within the accuracy of CPLEAR, the measured values of |eta_{+-}| and phi_{+-} are found not to be correlated with changes of the gravitational potential. We analyze data assuming effective scalar, vector and tensor interactions, and we conclude that the Principle of Equivalence between particles and antiparticles holds to a level of 6.5, 4.3 and 1.8 x 10^{-9}, respectively, for scalar, vector and tensor potentials originating from the Sun with a range much greater than the distance Earth-Sun. We also study energy-dependent effects that might arise from vector or tensor interactions. Finally, we compile upper limits on the gravitational coupling difference between K0 and K0bar as a function of the scalar, vector and tensor interaction range.Comment: 15 pages latex 2e, five figures, one style file (cernart.csl) incorporate

Functional cooperativity between the trigger factor chaperone and the ClpXP proteolytic complex

A functional association is uncovered between the ribosome-associated trigger factor (TF) chaperone and the ClpXP degradation complex. Bioinformatic analyses demonstrate conservation of the close proximity of tig, the gene coding for TF, and genes coding for ClpXP, suggesting a functional interaction. The effect of TF on ClpXP-dependent degradation varies based on the nature of substrate. While degradation of some substrates are slowed down or are unaffected by TF, surprisingly, TF increases the degradation rate of a third class of substrates. These include λ phage replication protein λO, master regulator of stationary phase RpoS, and SsrA-tagged proteins. Globally, TF acts to enhance the degradation of about 2% of newly synthesized proteins. TF is found to interact through multiple sites with ClpX in a highly dynamic fashion to promote protein degradation. This chaperone–protease cooperation constitutes a unique and likely ancestral aspect of cellular protein homeostasis in which TF acts as an adaptor for ClpXP

High-resolution and sensitivity bi-directional x-ray phase contrast imaging using 2D Talbot array illuminators

Two-dimensional (2D) Talbot array illuminators (TAIs) were designed, fabricated, and evaluated for high-resolution high-contrast x-ray phase imaging of soft tissue at 10–20 keV. The TAIs create intensity modulations with a high compression ratio on the micrometer scale at short propagation distances. Their performance was compared with various other wavefront markers in terms of period, visibility, flux efficiency, and flexibility to be adapted for limited beam coherence and detector resolution. Differential x-ray phase contrast and dark-field imaging were demonstrated with a one-dimensional, linear phase stepping approach yielding 2D phase sensitivity using unified modulated pattern analysis (UMPA) for phase retrieval. The method was employed for x-ray phase computed tomography reaching a resolution of 3 µm on an unstained murine artery. It opens new possibilities for three-dimensional, non-destructive, and quantitative imaging of soft matter such as virtual histology. The phase modulators can also be used for various other x-ray applications such as dynamic phase imaging, super-resolution structured illumination microscopy, or wavefront sensing