67 research outputs found

    Vertical cavity surface emitting laser based optoelectronic asynchronous transfer mode switch

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    Abstract. Large broadband asynchronous transfer mode (ATM) switching nodes require novel hardware solutions that could benefit from the inclusion of optical interconnect technology, since electronic solutions are limited by pin out and by the capacitance/inductance of the interconnections. We propose, analyze and demonstrate a new three stage free space optical switch that utilizes vertical cavity surface emitting lasers (VCSELs) for the optical interconnections, a liquid crystal spatial light modulator (SLM) as a reconfigurable shutter and relatively simple optics for fan out and fan in. A custom complementary metal oxide semiconductor (CMOS) chip is required to introduce a time delay in the optical bit stream and to drive the VCSELs. Analysis shows that the switch should be scalable to 1024ϫ1024, which would require 2048 ϳ2 mW VCSELs

    The Escherichia coli effector EspJ blocks Src kinase activity via amidation and ADP ribosylation

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    J.C.Y. was funded by an MRC PhD studentship. D.J.B. is supported by a London Research Institute, Cancer Research UK Postdoctoral Fellowship award and M.W. is supported by Cancer Research UK. K.A. was supported by the Deutsche Forschungsgemeinschaft (AK 6/22-1 and AK 6/22-2) and the Center for Biological Signaling Studies in Freiburg (Germany). This work was supported by grants from the Wellcome Trust to G.F. and S.J.M

    Impact of dietary organic acids and botanicals on intestinal integrity and inflammation in weaned pigs

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    BACKGROUND: Organic acids, such as citric and sorbic acid, and pure plant-derived constituents, like monoterpens and aldehydes, have a long history of use in pig feeding as alternatives to antibiotic growth promoters. However, their effects on the intestinal barrier function and inflammation have never been investigated. Therefore, aim of this study was to assess the impact of a microencapsulated mixture of citric acid and sorbic acid (OA) and pure botanicals, namely thymol and vanillin, (PB) on the intestinal integrity and functionality of weaned pigs and in vitro on Caco-2 cells. In the first study 20 piglets were divided in 2 groups and received either a basal diet or the basal diet supplemented with OA + PB (5 g/kg) for 2 weeks post-weaning at the end of which ileum and jejunum samples were collected for Ussing chambers analysis of trans-epithelial electrical resistance (TER), intermittent short-circuit current (I(SC)), and dextran flux. Scrapings of ileum mucosa were also collected for cytokine analysis (n = 6). In the second study we measured the effect of these compounds directly on TER and permeability of Caco-2 monolayers treated with either 0.2 or 1 g/l of OA + PB. RESULTS: Pigs fed with OA + PB tended to have reduced I(SC) in the ileum (P = 0.07) and the ileal gene expression of IL-12, TGF-β, and IL-6 was down regulated. In the in vitro study on Caco-2 cells, TER was increased by the supplementation of 0.2 g/l at 4, 6, and 14 days of the experiment, whereas 1 g/l increased TER at 10 and 12 days of treatment (P < 0.05). Dextran flux was not significantly affected though a decrease was observed at 7 and 14 days (P = 0.10 and P = 0.09, respectively). CONCLUSIONS: Overall, considering the results from both experiments, OA + PB improved the maturation of the intestinal mucosa by modulating the local and systemic inflammatory pressure ultimately resulting in a less permeable intestine, and eventually improving the growth of piglets prematurely weaned

    Ring Expansion of Cyclobutylmethylcarbenium Ions to Cyclopentane or Cyclopentene Derivatives and Metal-Promoted Analogous Rearrangements

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    Bristol's smart city agenda: vision, strategy, challenges and implementation

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