19 research outputs found

    Reliable Multicast Transport for Heterogeneous Mobile IP environment using Cross-Layer Information

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    Reliable multicast transport architecture designed for heterogeneous mobile IP environment using cross-layer information for enhanced Quality of Service (QoS) and seamless handover is discussed. In particular, application-specific reliable multicast retransmission schemes are proposed, which are aimed to minimize the protocol overhead taking into account behaviour of mobile receivers (loss of connectivity and handover) and the specific application requirements for reliable delivery (such as carousel, one-to-many download and streaming delivery combined with recording). The proposed localized retransmission strategies are flexible configured for tree-based multicast transport. Cross layer interactions in order to enhance reliable transport and support seamless handover is discussed considering IEEE 802.21 media independent handover mechanisms. The implementation is based on Linux IPv6 environment. Simulations in ns2 focusing on the benefits of the proposed multicast retransmission schemes for particular application scenarios are presented

    Topical inflammasome inhibition with disulfiram prevents irritant contact dermatitis

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    Background: The pathogenesis of contact dermatitis, a common inflammatory skin disease with limited treatment options, is held to be driven by inflammasome activation induced by allergens and irritants. We here aim to identify inflammasome-targeting treatment strategies for irritant contact dermatitis. Methods: A high content screen with 41,184 small molecules was performed using fluorescent Apoptosis associated speck-like protein containing a CARD (ASC) speck formation as a readout for inflammasome activation. Hit compounds were validated for inhibition of interleukin (IL)-1β secretion. Of these, the approved thiuramdisulfide derivative disulfiram was selected and tested in a patch test model of irritant contact dermatitis in 25 healthy volunteers. Topical application of disulfiram, mometasone or vehicle was followed by application of sodiumdodecylsulfate (SDS) for 24 h each. Eczema induction was quantified by mexameter and laser speckle imaging. Corneocyte sampling of lesional skin was performed to assess inflammasome-mediated cytokines IL-1β and IL-18. Results: Disulfiram induced a dose-dependent inhibition of ASC speck formation and IL-1β release in cellular assays in vitro. In vivo, treatment with disulfiram, but not with vehicle and less mometasone, inhibited SDS-induced eczema. This was demonstrated by significantly lower erythema and total perfusion values assessed by mexameter and laser speckle imaging for disulfiram compared to vehicle (p < 0.001) and/or mometasone (p < 0.001). Also, corneocyte IL-18 levels were significantly reduced after application of disulfiram compared to vehicle (p < 0.001). Conclusion: We show that disulfiram is a dose-dependent inhibitor of inflammasome pathway activation in vitro and inhibitor of SDS-induced eczema in vivo. Topical application of disulfiram represents a potential treatment option for irritant contact dermatitis

    Reliable multicast transport services for content delivery in heterogeneous mobile environment

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    For efficient deployment of new reliable multicast applications in heterogeneous mobile Internet environments, appropriate retransmission strategies are proposed. The focus is the minimization of the protocol overhead for reliable transport taking into account behaviour in mobile networks (oss and handover behaviour) and application requirements (such as carousel file transfer, one-to-many download and media streaming combined with recording). The proposed techniques are designed as building blocks for localized multicast error control supported by access routers. Considering IETF RMT standardization work, the discussed retransmission approaches can be used for flexible configuration of tree-based reliable multicast protocols in converged wired and wireless Internet environment. The implementation developed for the European project DAIDALOS [1] is based on Linux IPv6 environment. Simulations in ns2 focusing on the benefits of the proposed multicast retransmission schemes for particular application scenarios are presented

    <b>Metastable <i>P</i>-Tellurium-Substituted Phosphaalkenes: Formation, <sup>125</sup>Te- and <sup>31</sup>P-NMR Spectroscopic Characterization, and Decomposition</b>

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    <div><p></p><p>The formation and decomposition of P-tellurium-substituted phosphaalkenes was followed by <sup>31</sup>P- and <sup>125</sup>Te-NMR spectroscopy. Acyclic compounds with C˭P-Te moieties are in general thermally labile, but bulky substituents enhance the lifetime of a number of species. The P-chlorophosphaalkene (Me<sub>3</sub>Si)<sub>2</sub>C˭PCl (1a) reacts with the disilyltelluride (iPrMe<sub>2</sub>Si)<sub>2</sub>Te (2) leading to the mixed-substituted telluride (Me<sub>3</sub>Si)<sub>2</sub>C˭PTeSiMe<sub>2</sub>iPr 3a which reacts with another equivalent of 1a furnishing the tellurobis(phosphaalkene) [(Me<sub>3</sub>Si)<sub>2</sub>C˭P]<sub>2</sub>Te (4a). 4a is a shortlived compound decomposing thermally with precipitation of elemental tellurium, leading to a known diphosphabicyclobutane 5a. In a similar way, the bulkier P-chlorophosphaalkene (iPrMe<sub>2</sub>Si)<sub>2</sub>C˭PCl (1b) reacts with (iPrMe<sub>3</sub>Si)<sub>2</sub>Te furnishing [(iPrMe<sub>2</sub>Si)<sub>2</sub>C˭P]<sub>2</sub>Te (4b), which loses tellurium much more slowly than 4a and can be kept in cold solutions for an extended time. Reactions of in situ-prepared lithium aryltellurolates LiTeAr 6 – 9 [Ar˭Ph: 6, Ar˭2,4,6-Me<sub>3</sub>Ph (˭Mes): 7, Ar˭2,4,6-iPr<sub>3</sub>Ph (˭TIP): 8, Ar˭2,4,6-tBu<sub>3</sub>Ph (˭Mes*): 9] with 1a provide P-aryltellurophosphaalkenes 10 – 13, which decompose with the loss of diarylditellurides leading to 5a. After a 2 + 4 cycloaddition trapping experiment of 12 with cyclopentadiene, a metastable P-aryltelluro phosphanorbornene 14 was detected by <sup>31</sup>P-NMR. Reactions of elemental tellurium with P-phosphanylphosphaalkenes (Me<sub>3</sub>Si)<sub>2</sub>C˭PPR′R′;′ 15 – 17 (R′, R′′˭iPr: 15; R′˭iPr, R′′˭tBu: 16; R′, R′′˭tBu: 17) lead to metastable insertion products (Me<sub>3</sub>Si)<sub>2</sub>C˭PTePR′R′′ 18 – 20 that decompose with formation of the tellurobisphosphanes (R′R′′P)<sub>2</sub>Te 21 – 23, and of the bicyclic diphosphane 5a, which isomerises thermally to the diphosphabicyclooctane 24. The P-di-i-propylphosphanyl-phosphanorbornene 25 dismutates under the action of tellurium into the symmetric diphosphanes iPr<sub>4</sub>P<sub>2</sub> and bis-phosphanorbornene 26. The tellurium-free products 24 and 26 were characterized by X-ray crystallography.</p></div
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