Salmonella enterica serovar Typhimurium (S. Typhimurium) is a virulent pathogen that induces rapid host death. Here we observed that host survival after infection with S. Typhimurium was enhanced in the absence of type I interferon signaling, with improved survival of mice deficient in the receptor for type I interferons (Ifnar1(-/-) mice) that was attributed to macrophages. Although there was no impairment in cytokine expression or inflammasome activation in Ifnar1(-/-) macrophages, they were highly resistant to S. Typhimurium-induced cell death. Specific inhibition of the kinase RIP1 or knockdown of the gene encoding the kinase RIP3 prevented the death of wild-type macrophages, which indicated that necroptosis was a mechanism of cell death. Finally, RIP3-deficient macrophages, which cannot undergo necroptosis, had similarly less death and enhanced control of S. Typhimurium in vivo. Thus, we propose that S. Typhimurium induces the production of type I interferon, which drives necroptosis of macrophages and allows them to evade the immune response.

Neural task-oriented dialogue systems often struggle to smoothly interface with a knowledge base. In this work, we seek to address this problem by proposing a new neural dialogue agent that is able to effectively sustain grounded, multi-domain discourse through a novel key-value retrieval mechanism. The model is end-to-end differentiable and does not need to explicitly model dialogue state or belief trackers. We also release a new dataset of 3,031 dialogues that are grounded through underlying knowledge bases and span three distinct tasks in the in-car personal assistant space: calendar scheduling, weather information retrieval, and point-of-interest navigation. Our architecture is simultaneously trained on data from all domains and significantly outperforms a competitive rulebased system and other existing neural dialogue architectures on the provided domains according to both automatic and human evaluation metrics.

Metal-oxide-recast Nafion composite membranes were studied for operation in hydrogen/oxygen protonexchange membrane fuel cells (PEMFC) from 80 to 130 °C and at relative humidities ranging from 75 to 100%. Membranes of nominal 125 µm thickness were prepared by suspending a variety of metal oxide particles (SiO 2 , TiO 2 , Al 2 O 3 , and ZrO 2 ) in solubilized Nafion. The composite membranes were characterized using electrochemical, X-ray scattering, spectroscopic, mechanical, and thermal analysis techniques. Membrane characteristics were compared to fuel cell performance. These studies indicated a specific chemical interaction between polymer sulfonate groups and the metal oxide surface for systems that provide a good elevated-temperature (i.e., fuel-cell operation above 120 °C) performance. Composite systems that incorporate either a TiO 2 or a SiO 2 phase produced superior elevated-temperature, lowhumidity behavior compared to that of a simple Nafion-based fuel cell. Improved temperature tolerance permits the introduction of at least 500 ppm CO contaminant in the H 2 fuel stream without cell failure, in contrast to standard Nafion-based cells, which fail below 50 ppm of carbon monoxide.