RESUMO
Previous studies have shown that the formation of new memories can be influenced by prior experience. This includes work using pavlovian fear conditioning in rodents that have shown that an initial fear conditioning experience can become associated with and facilitate the acquisition of new fear memories, especially when they occur close together in time. However, most of the prior studies used only males as subjects resulting in questions about the generalizability of the findings from this work. Here we tested whether prior contextual fear conditioning would facilitate later learning of cued fear conditioning in both male and female rats, and if there were differences based on the interval between the two conditioning episodes. Our results showed that levels of cued fear were not influenced by prior contextual fear conditioning or by the interval between training, however, females showed lower levels of cued fear. Freezing behavior in the initial training context differed by sex, with females showing lower levels of contextual fear, and by the type of initial training, with rats given delayed shock showing higher levels of fear than rats given immediate shock during contextual fear conditioning. These results indicate that contextual fear conditioning does not prime subsequent cued fear conditioning and that female rats express lower levels of cued and contextual fear conditioning than males.
RESUMO
Currently, to reduce the environmental problems associated with plastic waste, methods are being sought to use this waste as raw materials in different applications, such as fibers. In addition, to improve these materials and provide different properties, nanoparticles (NPs) are incorporated. In the present work, polymeric fibers made of recycled polyethylene terephthalate (r-PET) from post-consumer water bottles, functionalized with 0%, 1.5%, 3% and 6% zinc oxide nanoparticles (ZnO-NPs) in function of r-PET weight, were elaborated to evaluate their antibacterial and antifungal characteristics. The ZnO-NPs were synthesized by the solvothermal method, obtaining particles with a mean diameter of 38.15 nm, while the fibers were obtained by electrospinning with a diameter range between 200-5000 nm. The functionalized fibers were carried out against Escherichia coli and Bacillus subtilis through the agar diffusion method, obtaining the highest inhibition halo at 6% w/w ZnO-NPs, being 26.5 mm and 34.25 mm, respectively. In addition, the same method was used to evaluate the antifungal activity of Penicillium s.p. and Fusarium graminearum, observing antifungal properties due to the presence of nanoparticles in the fibers.
RESUMO
This study reports the occurrence of a poorly differentiated carcinoma in a captive-born 28 year-old male chimpanzee (Pan troglodytes) who has a familial history of cancer. Pathological findings, surgical interventions, and experimental treatments are discussed.
