Adaptation of a microCT facility for automatic recognition of bioceramic-based sealers in molar root canals aimed at endodontic treatment quality control

Computed tomography (CT) technology has seen tremendous growth since its first medical applications in the early 1970s. Nowadays, high-spatial-resolution digital detectors enable the micro-computed tomography (μCT) technique, which has been introduced to a wide variety of applications, including biomedical sciences like odontological applications. Endodontic treatments stand as one of the most common dental procedures, and the quality of the treatment is essential to prevent and control any potential infection of root canals. This treatment is typically achieved by careful cleaning, shaping, and sealing steps. Often, endodontic treatments fail due to a poor seal, even if a meticulous root canal preparation is carried out. The present work reports on the spectrometric adaptation of a μCT facility for accurate quantification of root canal sealing with bioceramics, aimed at assessing the sealing performance of the new Bio-C Sealer product. A dedicated irradiation setup along with digital image processing techniques have been developed for the accurate and automatic recognition of dental samples root canal anatomy and bioceramic-based sealers. The performance of the proposed approaches has proved to be qualitatively and quantitatively robust for automatic characterization of the endodontic treatment sealing quality, satisfactorily identifying and segmenting canal root, gutta-percha cone, and bioceramics.     

A Survey on the Differential and Symplectic Geometry of Linking Numbers

The aim of the present survey mainly consists in illustrating some recently emerged differential and symplectic geometric aspects of the ordinary and higher order linking numbers of knot theory, within the modern geometrical and topological framework, constantly referring to their multifaceted physical origins and interpretations. Lecture held in the Seminario Matematico e Fisico on May 2, 2005 Received: May 2006     

Catalytic Membranes and Membrane Reactors： An Integrated Approach to Catalytic Process with a High Efficiency and a Low Environmental Impact

The design of new heterogeneous photooxygenation systems able to employ visible light,oxygen,mild temperatures,and solvent with a low environmental impact has been investigated. In particular,the heterogenization of decatungstate (W10O4-32),a polyoxometalate with photocatalytic activity in oxidation reactions,has been carried out in polymeric membranes of polyvinylidenefluoride. The polymeric catalytic membranes prepared by phase inversion technique have been successfully applied in the aerobic mineralization of phenol in water,which was used as an example of organic pollutant. In order to evaluate the effect of the polymeric environment on the overall catalyst behavior,we have also heterogenized the decatungstate (opportunely functionalized) in perfluorinated membrane made of Hyflon. The photocatalytic composite membranes are characterized by different and tuneable properties depending on the nature of the polymeric micro-environment,in which the catalyst is confined. Moreover,the selective separation function of the membrane results in enhanced performance in comparison with homogeneous reactions.     

A dynamical model of electoral competition

The paper presents the specific framework and a set of simulations computed on the basis of a kinetic model of interest in the field of the Social Sciences. The model is a reduced version of a comprehensive more general one, and it relates to the specific case of a competing bipartisan political system. The model structure contains terms with localized interactions and mean field terms. In the first part of the paper the mathematical details of the model are recalled. In the second part the simulations are presented with reference to the various scenarios examined. Finally a discussion on research perspectives is formulated.     

Causal Non-Stationary Thermodynamics of Non-Viscous Heat Conducting Fluids with Internal Variables

Relativistic non-viscous heat conducting fluids with a vectorial internal variable are modeled according to the dissipation and causality principles. A set of constitutive equations, ensuring the causal nature of the model, is postulated. The second law of thermodynamics is exploited by analyzing a suitable covariant form of the Clausius–Duhem inequality. A modification of the classical theory of heat conduction, allowing a finite speed of propagation of thermal disturbances, is considered.     

Gelatine sizing and discoloration: A comparative study of optical spectra obtained from ancient and artificially aged modern papers

The role of gelatine sizing in ancient paper discoloration is still subject to debate. In this report we have addressed this issue by comparing the optical reflectance of sized and non-sized artificially aged modern papers with reflectance data obtained from a set of ancient specimens. We have used different ageing procedures and prepared the gelatine following methods set down in ancient recipes. Gelatine-sized aged papers showed an optical response comparable with that of ancient paper specimens, while very small reflectance modifications were observed in pure cellulose unsized samples under the same ageing conditions. In addition, measurements carried out on pure gelatine films confirmed that gelatine plays a major role in paper discoloration. Some differences in discoloration effects induced by artificial and natural ageing on sized paper are discussed and a possible explanation is proposed.     

Large quartic groups on translation planes,II—Even order: Characterization of the Ott‐Schaeffer planes

A general theory of collineation groups generated by quartic groups of even order is considered. Applications are given to collineation groups generated by ‘large’ quartic groups. © 2005 Wiley Periodicals, Inc. J Combin Designs 13: 195–210, 2005.     

Oscillation of coupled nonlinear discrete systems

The problem of oscillation of a second order nonlinear difference system is considered and conditions for oscillation are derived by means of a complete analysis of nonoscillatory solutions. The case of systems with deviating arguments is also analyzed, and the results are shown to significantly generalize some existing ones.     

Numerical Modeling of PMD

A procedure for evaluating system performance considering all orders of polarization mode dispersion (PMD) is presented. The method provides engineering rules for computing system penalty introduced by PMD. Computer simulation of PMD induced penalty indicates that for generating a realistic system budget, effect of higher order PMD in presence of chromatic dispersion is essential. Considering all of these penalties, in order to obtain a system-reach of 3200 km at 40 Gb/s, a fiber PMD of less than 0.04 ps/km^1/2 is required when at the signal wavelength chromatic dispersion is 0. In presence of 18 ps/nm chromatic dispersion for the same system reach this PMD value reduces to about 0.02 ps/km^1/2.