Synthesis and characterization of lanthanum bonded agar-carbomer hydrogel:a promising tool for biomedical research

Agar-Carbomer(branched poly(acrylic acid)) hydrogel,an injectable bio-resorbable scaffold with a controlled nanostructure specifically designed for neural cell housing,was developed together with a new protocol for building three dimensional biohybrid cell/hydrogel systems.In order to overcome classic structural analysis inconveniences due to the high water amount,which affects instruments results and reliability,agar-Carbomer hydrogels were synthesized by microwave-assisted block copolymerization together with La3+ salts.Propylene glycol,glycerol and buffered saline solution were used as cross-linking agents and solvent,respectively.Biomaterial properties were not affected by the presence of lanthanum,and were checked via swelling and rheological analysis.Moreover,the presence of La3+ within the polymeric network was characterized by thermogravimetric analysis,environmental scanning electron microscopy and Fourier transformed infrared spectroscopy.The results showed that the rare earth presented uniform distribution in the hydrogel network due to the formation of chemical bonds after polymerization without being modified its luminescence emission spectrum that allowed hydrogel detection.These results made the obtained host-guest system a useful tool for analytical research studies concerning regenerative medical applications that could also be potentially taken up with in vivo experiments.     

Space and time basis function design for the method of moments in time‐domain analysis of wire and planar structures

In this article, an algorithm able to deal at the same time with wire frame and surface patch models for the method of moments in time domain is presented. After a unified theory combining both models, attention is focused on stability dependence issues on the time basis function chosen and on other algorithm parameters. An accurate analysis of time interpolation functions and of their time filtering properties is provided. © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2011.     

Dietary citrus pulp improves protein stability in lamb meat stored under aerobic conditions

The antioxidant effects of dried citrus pulp on proteins in lamb meat, when used as a replacement of concentrate in the feed, was studied using meat from 26 male Comisana lambs. The lambs of age 90 days had been grouped randomly to receive one of the three dietary treatments: (1) commercial concentrate with 60% barley (Control, n = 8), (2) concentrate with 35% barley and 24% citrus pulp (Cp24, n = 9), or (3) concentrate with 23% barley and 35% citrus pulp (Cp35, n = 9). Slices from the longissimus thoracis et lomborum muscle were packed aerobically and stored for up to 6 days at 4°C in the dark. The citrus pulp groups, Cp24 and Cp35, significantly decreased protein radicals and carbonyls, and preserved more thiols within six days of storage compared to the Control group. The citrus pulp groups significantly slowed down the rate of protein oxidation, indicating that dietary citrus pulp reduced oxidative changes in meat proteins.     

A general framework for modeling long-term behavior of earth and concrete dams

Many problems are linked with the long-term behavior of both earthdams and concrete dams. They range from hydraulic fracturing to alkali-silica reaction (ASR) and to repair work in concrete dams, from seismic behavior to secondary consolidation in earthdams. A common framework for the simulation of such systems is shown, based on the mechanics of multiphase porous media. The general model is particularized to specific situations and several examples are shown.     

A new software architecture for developing and testing algorithms for space exploration missions

In recent years, planet exploration has received an increasing interest due to the possibility of exploiting planet resources and assuring a human–robotic colonized presence on suitable planetary surfaces. These goals can be reached through the development of smart robots, which are able to work on their own and without requiring a constant human supervision but, at the same time, assuring a great level of safety and reliability. To this aim, the development of effective architectures, concerning both software and hardware issues, could represent a great improvement toward this ambitious objective. This paper presents a novel modular architecture called Test Bench for Robotics and Autonomy (TBRA), the main objective of which is to create a test bench for rover autonomy missions where different implementations of a particular subsystem can be easily tested, while keeping the rest of the system unchanged. Thus, it allows the developers to be able to compare the results of tests and understand which version works better. Such architecture has been built on top of the Workframe, a generic middleware for real-time robotics. This two-layered approach allows the final user to deal only with the TBRA interface, which is designed to be extremely simple to use and takes care of most real-time programming problems, while allowing flexibility in the development, maintenance and future extension of the TBRA itself.     

Analytical solution for composite layered beam subjected to uniformly distributed load

The article presents an analytical theory for multilayered composite beams subjected to transverse uniformly distributed loads. The formulation is based on a layerwise model characterized by third-order approximation of the axial displacements and fourth-order approximation of the transverse displacements. The layerwise kinematical model is rewritten in terms of generalized variables. The beam equilibrium equations, expressed in terms of stress resultant, allow writing the boundary value governing problem. The layerwise fields are obtained by postprocessing steps. The main advantage is to ensure the accuracy level associated to the layerwise formulations preserving the computational efficiency of the equivalent-single-layer theories.     

Evaluation of Po River water quality in Torino (Italy): Effects of diffuse and local point loads

The aim of this paper is to examine the Po River water quality in a small stretch in Piedmont (northern Italy). In this stretch a large pollution load, derived from the wastewater treatment plant of Torino area (more than 2 million inhabitants), is discharged and diluted in the water. In this study this load has been quantified and modeled in order to understand the sources, destinations and effects of the emitted pollutants. The objective was to determine the impact produced by the Torino Wastewater Treatment Plant on the quality of the water, based on various hydrological conditions and the possible intervention on the point and diffuse loads.     

Nanoscale characterization of the biomechanical hardening of bovine zona pellucida

The zona pellucida (ZP) is an extracellular membrane surrounding mammalian oocytes. The so-called zona hardening plays a key role in fertilization process, as it blocks polyspermy, which may also be caused by an increase in the mechanical stiffness of the ZP membrane. However, structural reorganization mechanisms leading to ZP''s biomechanical hardening are not fully understood yet. Furthermore, a correct estimate of the elastic properties of the ZP is still lacking. Therefore, the aim of the present study was to investigate the biomechanical behaviour of ZP membranes extracted from mature and fertilized bovine oocytes to better understand the mechanisms involved in the structural reorganization of the ZP that may lead to the biomechanical hardening of the ZP. For that purpose, a hybrid procedure is developed by combining atomic force microscopy nanoindentation measurements, nonlinear finite element analysis and nonlinear optimization. The proposed approach allows us to determine the biomechanical properties of the ZP more realistically than the classical analysis based on Hertz''s contact theory, as it accounts for the nonlinearity of finite indentation process, hyperelastic behaviour and material heterogeneity. Experimental results show the presence of significant biomechanical hardening induced by the fertilization process. By comparing various hyperelastic constitutive models, it is found that the Arruda–Boyce eight-chain model best describes the biomechanical response of the ZP. Fertilization leads to an increase in the degree of heterogeneity of membrane elastic properties. The Young modulus changes sharply within a superficial layer whose thickness is related to the characteristic distance between cross-links in the ZP filamentous network. These findings support the hypothesis that biomechanical hardening of bovine ZP is caused by an increase in the number of inter-filaments cross-links whose density should be higher in the ZP inner side.