1,671 research outputs found

    Inactivation in ShakerB K+ channels: a test for the number of inactivating particles on each channel

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    Fast inactivation in ShakerB K channels results from pore-block caused by "ball peptides" attached to the inner part of each K channel. We have examined the question of how many functional inactivating balls are on each channel and how this number affects inactivation and recovery from inactivation. To that purpose we expressed ShakerB in the insect cell line Sf9 and gradually removed inactivation by perfusing the cell interior with the hydrolytic enzyme papain under whole cell patch clamp. Inactivation slows down as the balls are removed by an amount consistent with the presence of four balls on each channel. Recovery from inactivation has the same time course early and late in papain action; it does not depend on the number of balls remaining on the channel, consistent with the idea that reinactivation is not significant during recovery from inactivation. Our conclusion is that ShakerB has four ball peptides, each capable of causing inactivation. Statistically, the balls are identical and independent. The stability of N-type inactivation by the remaining balls is not appreciably affected by removing some of the balls from a channel

    Activating integrins isn't always "beta" for neutrophil migration!

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    The lungs possess extraordinary defenses against bacteria and other stimuli. Initial mechanisms of host defense include the very effective mucociliary escalator and the alveolar macrophages,which clearmany stimuli without inducing an inflammatory response and recruitment of circulating leukocytes. When these defenses are overwhelmed, epithelial cells andmacrophages call in help fromoutside the lungs. In response to bacteria, neutrophils are usually first to arrive, and their response is quick, recognizing a need within minutes

    From E_8 to F via T

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    We argue that T-duality and F-theory appear automatically in the E_8 gauge bundle perspective of M-theory. The 11-dimensional supergravity four-form determines an E_8 bundle. If we compactify on a two-torus, this data specifies an LLE_8 bundle where LG is a centrally-extended loopgroup of G. If one of the circles of the torus is smaller than sqrt(alpha') then it is also smaller than a nontrivial circle S in the LLE_8 fiber and so a dimensional reduction on the total space of the bundle is not valid. We conjecture that S is the circle on which the T-dual type IIB theory is compactified, with the aforementioned torus playing the role of the F-theory torus. As tests we reproduce the T-dualities between NS5-branes and KK-monopoles, as well as D6 and D7-branes where we find the desired F-theory monodromy. Using Hull's proposal for massive IIA, this realization of T-duality allows us to confirm that the Romans mass is the central extension of our LE_8. In addition this construction immediately reproduces the conjectured formula for global topology change from T-duality with H-flux.Comment: 25 pages, 4 eps figure

    320-to-10 Gbit/s all-optical demultiplexing using sum-frequency generation in PPLN waveguide

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    A 320-to-10 Gbit/s all-optical demultiplexer based on sum-frequency generation in a periodically-poled lithium niobate (PPLN) waveguide is demonstrated. A bit-error-rate of 10-9 is achieved with a power penalty of 1.5 dB

    Metabolic syndrome before puberty: Myth or reality?

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    Metabolic syndrome (MetS) is defined as a cluster of alterations related with insulin resistance (obesity, dyslipidemia, hypertension, and impaired glucose metabolism), which are associated with a higher risk of cardiovascular disease in adults. Several definitions have been proposed for older children and adolescents. However, no definitions have been made in accordance with pubertal status, and those in prepubertal state have not received attention enough, despite there are data suggesting the early presence of risk factors. The new insights concerning healthy and unhealthy metabolic status or the addition of novel metabolic risk biomarkers, may contribute to the knowledge about the development of MetS in children. This manuscript reviews the available evidence on MetS during childhood, focusing on the prepubertal period

    Twisted K-Theory from Monodromies

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    RR fluxes representing different cohomology classes may correspond to the same twisted K-theory class. We argue that such fluxes are related by monodromies, generalizing and sometimes T-dual to the familiar monodromies of a D7-brane. A generalized theta angle is also transformed, but changes by a multiple of 2pi. As an application, NS5-brane monodromies modify the twisted K-theory classification of fluxes. Furthermore, in the noncompact case K-theory does not distinguish flux configurations in which dG is nontrivial in compactly supported cohomology. Such fluxes are realized as the decay products of unstable D-branes that wrapped nontrivial cycles. This is interpreted using the E8 bundle formalism.Comment: 24 Pages, 6 eps figure

    Dynamic changes in lung responses after single and repeated exposures to cigarette smoke in mice

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    Cigarette smoke is well recognized to cause injury to the airways and the alveolar walls over time. This injury usually requires many years of exposure, suggesting that the lungs may rapidly develop responses that initially protect it from this repetitive injury. Our studies tested the hypotheses that smoke induces an inflammatory response and changes in mRNA profiles that are dependent on sex and the health status of the lung, and that the response of the lungs to smoke differs after 1 day compared to 5 days of exposure. Male and female wildtype (WT) and Scnn1b-transgenic (βENaC) mice, which have chronic bronchitis and emphysematous changes due to dehydrated mucus, were exposed to cigarette smoke or sham air conditions for 1 or 5 days. The inflammatory response and gene expression profiles were analyzed in lung tissue. Overall, the inflammatory response to cigarette smoke was mild, and changes in mediators were more numerous after 1 than 5 days. βENaC mice had more airspace leukocytes than WT mice, and smoke exposure resulted in additional significant alterations. Many genes and gene sets responded similarly at 1 and 5 days: genes involved in oxidative stress responses were upregulated while immune response genes were downregulated. However, certain genes and biological processes were regulated differently after 1 compared to 5 days. Extracellular matrix biology genes and gene sets were upregulated after 1 day but downregulated by 5 days of smoke compared to sham exposure. There was no difference in the transcriptional response to smoke between WT and βENaC mice or between male and female mice at either 1 or 5 days. Taken together, these studies suggest that the lungs rapidly alter gene expression after only one exposure to cigarette smoke, with few additional changes after four additional days of repeated exposure. These changes may contribute to preventing lung damage

    Improving the Accuracy of Action Classification Using View-Dependent Context Information

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    Proceedings of: 6th International Conference, HAIS 2011, Wroclaw, Poland, May 23-25, 2011This paper presents a human action recognition system that decomposes the task in two subtasks. First, a view-independent classifier, shared between the multiple views to analyze, is applied to obtain an initial guess of the posterior distribution of the performed action. Then, this posterior distribution is combined with view based knowledge to improve the action classification. This allows to reuse the view-independent component when a new view has to be analyzed, needing to only specify the view dependent knowledge. An example of the application of the system into an smart home domain is discussed.This work was supported in part by Projects CICYT TIN2008-06742-C02-02/ TSI, CICYT TEC2008-06732-C02-02/TEC, CAM CONTEXTS (S2009/ TIC-1485) and DPS2008-07029-C02-02.Publicad
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