Conformal PML-FDTD schemes for electromagnetic field simulations: adynamic stability study

We present a study on the dynamic stability of the perfectly matched layer (PML) absorbing boundary condition for finite-difference time-domain (FDTD) simulations of electromagnetic radiation and scattering problems in body-conformal orthogonal grids. This work extends a previous dynamic stability analysis of Cartesian, cylindrical and spherical PMLs to the case of a conformal PML. It is shown that the conformal PML defined over surface terminations with positive local radii of curvature (concave surfaces as viewed from inside the computational domain) is dynamically stable, while the conformal PML defined over surface terminations with a negative local radius (convex surfaces as viewed from inside the computational domain) is dynamically unstable. Numerical results illustrate the analysis     

Study of the myenteric and submucous plexuses after BAC treatment in the intestine of rats.

A morphological and quantitative study in the ileal and colonic myenteric and submucous plexuses of rats after BAC denervation was performed. Four groups were employed: SI--ileum control; CBI--denervated ileum; SC--colon control; and CBC--denervated colon. We used the Myosin-V immunohistochemistry technique to study the myenteric and submucous plexuses. In the submucous plexus of the ileum and colon there was not a significant decrease in the number of neurons/mm2 and of ganglia/mm2. The denervation of the myenteric plexus in the group CBI was 44.7% and in the group CBC, 68.3%. In the myenteric plexus there was also a significant decrease in the number of ganglia/mm2 (13.8% in group CBI and 52.14% in group CBC) and in the number of neurons/ganglion (33.9% in group CBI and 39.6% in group CBC). The morphological analyses showed that there was an alteration in the shape of the ganglia of the ileal and colonic myenteric plexus. The area of the cell bodies had a significant increase both in the myenteric and the submucous plexus in groups CBI and CBC. These data demonstrate that the BAC treatment causes morphologic and quantitative changes in the myenteric plexus and quantitative changes in the cell body area of the submucous plexus.     

Development of pullulan-based carriers for controlled release of hydrophobic ingredients

Polymeric nanoparticles have great potential for targeted and controlled delivery of drugs for several health treatments. In this work, pullulan-graft-poly(ε-caprolactone) (Pull-g-PCL) nanoparticles were prepared and used to encapsulate indomethacin via dialysis. The nanoparticles were characterized with respect to size, size distribution, and morphology, using dynamic light scattering and transmission electron microscopy. The average diameter of nanoparticles was 220.0 and 273.7 nm, with and without indomethacin, respectively. Encapsulation of indomethacin and its release from the nanoparticles were studied, and the calculated value of indomethacin efficiency encapsulation was 35.05 wt%. The ensuing release kinetics were evaluated in vitro at 37°C and pH 7.4 and evidenced the efficiency of polymer nanoparticles in reducing the release rate of the ingredient. Pull-g-PCL nanoparticles represent, therefore, promising materials with potential for application in controlled release systems of hydrophobic substances.     

CeO2 and CeO2:Pr nanocrystalline powders prepared by the polymeric precursor method: Yellow and red pigments with tunable color

The development of stable and reproducible inorganic pigments is noteworthy for industrial applications mainly considering more intense shades and low toxicity. Among the various candidates to substitute non-hazardous red and yellow pigments, CeO₂ and CeO₂:Pr have been attracting attention because of their opacity and high-temperature stability besides being environmental-friendly and health-friendly. In this study, nanostructured CeO₂ and CeO₂:Pr samples were synthesized using the polymeric precursor method and structural and optical characterizations were performed. Scanning electron microscopy reveals the morphology of CeO₂ nanoparticles in which the particle size ranges from 22 to 28 nm as a function of the annealing temperature. Pr-doping does not show influence on the particle size. XRD results show that CeO₂ and CeO₂:Pr samples crystallize in the cubic fluorite lattice with Fm3m space group. Raman spectra show the fluorite F_2g mode, confirming the XRD results. With Pr-doping and the annealing of the samples, two bands are observed between 550 and 600 cm⁻¹, which are related to the defects in the fluorite structure associated with oxygen vacancies. XPS spectra reveal an increase in the ratio of Ce³⁺ ions depending on the annealing temperature and Pr-doping. This increase is associated with the carbon removal from the lattice by annealing. This behavior causes a change in the hue of the powders as the annealing temperature increases. According to diffuse reflectance and colorimetric measurements, CeO₂ shows a light-yellow color due to the O 2p­Ce 4f transitions whose b* parameter mainly decreases with annealing, becoming almost white. The CeO₂:Pr sample exhibits a red-orange color because of the electronic transitions between 4f² → 5d¹ states of Pr³⁺. Upon annealing, L* and b* parameters decrease, resulting in a red-brown shade. The charge compensation or charge transfer is responsible for the modification of the hue of these pigments.     

Validation of Innovative Food Microbiological Methods According to the EN ISO 16140 Standard

Reference methods in food microbiology are mostly based on conventional microbiology. Innovative methods have been developed and commercialised, with several advantages, but their users need guarantees on their performance. Validation schemes have thus been established to assess whether these methods perform at least as well as the corresponding reference methods. In addition, a European and International Standard, EN ISO 16140, has been developed to provide a common reference protocol for the validation of alternative methods, as well as to determine general principles for their possible subsequent certification. The content of this standard is summarised, a technical protocol is defined separately for qualitative and quantitative methods and the validation study, which comprises two phases, a comparative study and an inter-laboratory study, is described. This standard is currently being revised and the main directions taken are presented. This paper then briefly introduces the validation/certification systems before addressing several aspects related to the links with laboratory accreditation and European regulations on microbiological criteria, as well as the use of alternative methods.     

Real-Time 3D Stereo Tracking and Localizing of Spherical Objects with the iCub Robotic Platform

Visual pattern recognition is a basic capability of many species in nature. The skill of visually recognizing and distinguishing different objects in the surrounding environment gives rise to the development of sensory-motor maps in the brain, with the consequent capability of object reaching and manipulation. This paper presents the implementation of a real-time tracking algorithm for following and evaluating the 3D position of a generic spatial object. The key issue of our approach is the development of a new algorithm for pattern recognition in machine vision, the Least Constrained Square-Fitting of Ellipses (LCSE), which improves the state of the art ellipse fitting procedures. It is a robust and direct method for the least-square fitting of ellipses to scattered data. In this work we applied it to the iCub humanoid robotics platform simulator and real robot. We used it as a base for a circular object localization within the 3D surrounding space. We compared its performance with the Hough Transform and the state of the art ellipse fitting algorithms, in terms of robustness (succes/failure in the object detection) and fitting precision. Our experiments involve robustness against noise, occlusion, and computational complexities analyses.