To study central nervous system airborne PM related subchronic toxicity, SD male rats were exposed for eight weeks to either coarse (32 µg/m3), fine (178 µg/m3) or ultrafine (107 µg/m3) concentrated PM or filtered air. Different brain regions (olfactory bulb, frontal cortex, striatum and hippocampus), were harvested from the rats following exposure to airborne PM. Subsequently, prooxidant (HO-1 and SOD-2), and inflammatory markers (IL-1β and TNFα), apoptotic (caspase 3), and unfolded protein response (UPR) markers (XBP-1S and BiP), were also measured using real-time PCR. Activation of nuclear transcription factors Nrf-2 and NF-κB, associated with antioxidant and inflammation processes, respectively, were also analyzed by GSMA. Ultrafine PM increased HO-1 and SOD-2 mRNA levels in the striatum and hippocampus, in the presence of Nrf-2 activation. Also, ultrafine PM activated NF-κB and increased IL-1β and TNFα in the striatum. Activation of UPR was observed after exposure to coarse PM through the increment of XBP-1S and BiP in the striatum, accompanied by an increase in antioxidant response markers HO-1 and SOD-2. Our results indicate that exposure to different size fractions of PM may induce physiological changes (in a neuroanatomical manner) in the central nervous system (CNS), specifically within the striatum, where inflammation, oxidative stress and UPR signals were effectively activated.

Here we present measurements on the gel time of inorganic-organic materials used for stone preservation by means of rheology and dynamic light scattering. Our hybrid material is composed of tetraethyl orthosilicate (TEOS) and polydimethylsiloxane (PDMS) using a nonionic surfactant (n-octylamine) as a template. Moreover, zinc oxide (ZnO) nanoparticles are dispersed in the medium with the aim of obtaining a nanocomposite with potential biocide properties. In our case, we use the ZnO particles as tracers to infer from their scattered intensity mechanical information of the suspending medium. We have found that dynamic light scattering experiments provide similar information on the gelling time, about 30 hours, to that obtained from rotational rheology and oscillatory rheology. This result confirms the validity of light scattering, which is a noninvasive technique, to characterize mechanical properties of time evolving hybrid materials through nonperturbative and well-controlled experiments.