Marche Polytechnic University

About: Marche Polytechnic University is a education organization based out in Ancona, Italy. It is known for research contribution in the topics: Population & Prostate cancer. The organization has 5905 authors who have published 15769 publications receiving 382286 citations. The organization is also known as: Universitá Politecnica delle Marche & Universita Politecnica delle Marche.

Effect of DIC Spatial Resolution, Noise and Interpolation Error on Identification Results with the VFM

Abstract: The use of experimental tests that involve full-field measurements to characterize mechanical material properties is becoming more widespread within the engineering community. In particular digital image correlation (DIC) on white light speckles is one of the most used tools, thanks to the relatively low cost of the equipment and the availability of dedicated software. Nonetheless the impact of measurement errors on the identified parameters is still not completely understood. To this purpose, in this paper, a simulator able to numerically simulate an experimental test, which involves DIC is presented. The chosen test is the Unnotched Iosipescu test used to identify the orthotropic elastic parameters of composites. Synthetic images are generated and then analysed by DIC. Eventually the obtained strain maps are used to identify the elastic parameters with the Virtual Fields Method (VFM). The numerical errors propagating through the simulation procedure are carefully characterized. Besides, the simulator is used to compare the performances of DIC and the grid method in the identification process with the VFM. Finally, the influence of DIC settings on the identification error is studied as a function of the camera digital noise level, in order to find the best testing configuration.

Presynaptic NMDA receptors in the neocortex are both auto- and heteroreceptors

Abstract: We used electron microscopic immunocytochemistry with antibodies against NR1 and NR2A and B subunits to study the distribution of N-methyl-D-aspartate (NMDA) receptors in presynaptic axon terminals in the rat cerebral cortex. In all sections examined, NR1 and NR2A/B immunoreactivities were observed in axon terminals: NR1- and NR2A/B-positive axon terminals made both symmetrical and asymmetrical synapses on unlabelled dendritic profiles. Combined pre- and postembedding studies showed that all NR1 and NR2A/B-positive axon terminals making symmetrical synapses were gamma-aminobutyric acid (GABA)-positive. These observations show that both auto- and hetero- NMDA receptors do exist in the cerebral cortex, and indicate that part of the effects of NMDA receptor activation might be determined by modulating glutamate and GABA release.