141 research outputs found

    One More Weight is Enough: Toward the Optimal Traffic Engineering with OSPF

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    Traffic Engineering (TE) leverages information of network traffic to generate a routing scheme optimizing the traffic distribution so as to advance network performance. However, optimize the link weights for OSPF to the offered traffic is an known NP-hard problem. In this paper, motivated by the fairness concept of congestion control, we firstly propose a new generic objective function, where various interests of providers can be extracted with different parameter settings. And then, we model the optimal TE as the utility maximization of multi-commodity flows with the generic objective function and theoretically show that any given set of optimal routes corresponding to a particular objective function can be converted to shortest paths with respect to a set of positive link weights. This can be directly configured on OSPF-based protocols. On these bases, we employ the Network Entropy Maximization(NEM) framework and develop a new OSPF-based routing protocol, SPEF, to realize a flexible way to split traffic over shortest paths in a distributed fashion. Actually, comparing to OSPF, SPEF only needs one more weight for each link and provably achieves optimal TE. Numerical experiments have been done to compare SPEF with the current version of OSPF, showing the effectiveness of SPEF in terms of link utilization and network load distribution

    Interferon-β-induced miR-155 inhibits osteoclast differentiation by targeting SOCS1 and MITF

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    AbstractIFN-β is induced via a c-fos dependent mechanism that is present downstream of the receptor activator of NF-κB ligand (RANKL)-RANK signal transduction cascade during osteoclast differentiation. Increased production of IFN-β in turn inhibits osteoclastogenesis. However, the mechanism by which IFN-β exerts its suppressive function remains unclear. In the present study, we found that miR-155, an IFN-β-induced miRNA, mediated the suppressive effect of IFN-β on osteoclast differentiation by targeting SOCS1 and MITF, two essential regulators of osteoclastogenesis. These findings have not only demonstrated that miR-155 inhibits osteoclast differentiation, but also provided a new therapeutic target for treatment of osteoclast-mediated diseases

    Recruitment of Endophilin to Clathrin-Coated Pit Necks Is Required for Efficient Vesicle Uncoating after Fission

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    SummaryEndophilin is a membrane-binding protein with curvature-generating and -sensing properties that participates in clathrin-dependent endocytosis of synaptic vesicle membranes. Endophilin also binds the GTPase dynamin and the phosphoinositide phosphatase synaptojanin and is thought to coordinate constriction of coated pits with membrane fission (via dynamin) and subsequent uncoating (via synaptojanin). We show that although synaptojanin is recruited by endophilin at bud necks before fission, the knockout of all three mouse endophilins results in the accumulation of clathrin-coated vesicles, but not of clathrin-coated pits, at synapses. The absence of endophilin impairs but does not abolish synaptic transmission and results in perinatal lethality, whereas partial endophilin absence causes severe neurological defects, including epilepsy and neurodegeneration. Our data support a model in which endophilin recruitment to coated pit necks, because of its curvature-sensing properties, primes vesicle buds for subsequent uncoating after membrane fission, without being critically required for the fission reaction itself

    The Mechanism of (R,R) ZX-5 on Increasing NO Release

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    (R,R) ZX-5 has been proven to have positive effects on choroidal blood flow without affecting the sclera and ciliary bodies in New Zealand white rabbits. This study was designed to investigate the mechanisms of (R,R) ZX-5 on improving the choroidal blood flow and promoting NO production. HUVECs (human umbilical vein endothelial cells) were used to determine the production of eNOS, p-eNOS, AKT and Erk1/2 by Western blot analysis. iNOS and eNOS mRNA levels were investigated by RT-PCR and the effect of (R,R) ZX-5 on NO production were determined by eNOS activity assay. We found (R,R) ZX-5 upregulated protein expression of eNOS and iNOS, increased NO production, and reduced ERK and Akt protein level. Therefore, (R,R) ZX-5 may promote the choroidal blood flow in New Zealand white rabbits without affecting the blood flow in the iris or ciliary bodies via increasing NO production. These results suggest that (R,R) ZX-5 may function to cure and prevent Age-related macular degeneration (AMD)
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