14,011 research outputs found

    TGFβ/BMP immune signaling affects abundance and function of C. elegans gut commensals.

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    The gut microbiota contributes to host health and fitness, and imbalances in its composition are associated with pathology. However, what shapes microbiota composition is not clear, in particular the role of genetic factors. Previous work in Caenorhabditis elegans defined a characteristic worm gut microbiota significantly influenced by host genetics. The current work explores the role of central regulators of host immunity and stress resistance, employing qPCR and CFU counts to measure abundance of core microbiota taxa in mutants raised on synthetic communities of previously-isolated worm gut commensals. This revealed a bloom, specifically of Enterobacter species, in immune-compromised TGFβ/BMP mutants. Imaging of fluorescently labeled Enterobacter showed that TGFβ/BMP-exerted control operated primarily in the anterior gut and depended on multi-tissue contributions. Enterobacter commensals are common in the worm gut, contributing to infection resistance. However, disruption of TGFβ/BMP signaling turned a normally beneficial Enterobacter commensal to pathogenic. These results demonstrate specificity in gene-microbe interactions underlying gut microbial homeostasis and highlight the pathogenic potential of their disruption

    Use of inhibitory solvents in multi-membrane bioreactor

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    An immobilized liquid membrane is employed to allow use of a product-extracting solvent which is normally toxic toward a cell layer which produces the product in a membrane-moderated biological reaction

    Graphene Spin Transistor

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    Graphitic nanostructures, e.g. carbon nanotubes (CNT) and graphene, have been proposed as ideal materials for spin conduction[1-7]; they have long electronic mean free paths[8] and small spin-orbit coupling[9], hence are expected to have very long spin-scattering times. In addition, spin injection and detection in graphene opens new opportunities to study exotic electronic states such as the quantum Hall[10,11] and quantum spin Hall[9] states, and spin-polarized edge states[12] in graphene ribbons. Here we perform the first non-local four-probe experiments[13] on graphene contacted by ferromagnetic Permalloy electrodes. We observe sharp switching and often sign-reversal of the non-local resistance at the coercive field of the electrodes, indicating definitively the presence of a spin current between injector and detector. The non-local resistance changes magnitude and sign quasi-periodically with back-gate voltage, and Fabry-Perot-like oscillations[6,14,15] are observed, consistent with quantum-coherent transport. The non-local resistance signal can be observed up to at least T = 300 K

    Urea Degradation by Electrochemically Generated Reactive Chlorine Species: Products and Reaction Pathways

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    This study investigated the transformation of urea by electrochemically generated reactive chlorine species (RCS). Solutions of urea with chloride ions were electrolyzed using a bismuth doped TiO_2 (BiOx/TiO_2) anode coupled with a stainless steel cathode at applied anodic potentials (E_a) of either +2.2 V or +3.0 V versus the normal hydrogen electrode. In NaCl solution, the current efficiency of RCS generation was near 30% at both potentials. In divided cell experiments, the pseudo-first-order rate of total nitrogen decay was an order of magnitude higher at E_a of +3.0 V than at +2.2 V, presumably because dichlorine radical (Cl_2–•) ions facilitate the urea transformation primary driven by free chlorine. Quadrupole mass spectrometer analysis of the reactor headspace revealed that N_2 and CO_2 are the primary gaseous products of the oxidation of urea, whose urea-N was completely transformed into N_2 (91%) and NO_3– (9%). The higher reaction selectivity with respect to N_2 production can be ascribed to a low operational ratio of free available chlorine to N. The mass-balance analysis recovered urea-C as CO_2 at 77%, while CO generation most likely accounts for the residual carbon. In light of these results, we propose a reaction mechanism involving chloramines and chloramides as reaction intermediates, where the initial chlorination is the rate-determining step in the overall sequence of reactions

    Stability of the Magnetic Monopole Condensate in three- and four-colour QCD

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    It is argued that the ground state of three- and four-colour QCD contains a monopole condensate, necessary for the dual Meissner effect to be the mechanism of confinement, and support its stability on the grounds that it gives the off-diagonal gluons an effective mass sufficient to remove the unstable ground state mode.Comment: jhep.cls, typos corrected, references added, some content delete

    Generating an Online Bottom Line

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    E-commerce is an approach to achieving business goals through information technology and is quickly changing the way hospitality business is planned, monitored, and conducted. No longer do buyers and sellers need to engage in interpersonal communications for transactions to occur. The future of transaction processing, which includes cyber cash and digital checking, are directly attributable to e-commerce which provides and efficient, reliable, secure, and effective platform for conducting hospitality business on the web
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