108 research outputs found

    LEACH-CR: energy saving hierarchical network protocol based on low-energy adaptive clustering hierarchy for wireless sensor networks

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    Wireless Sensor Network consists of hundreds to thousands of tiny sensor nodes deployed in the large field of the target phenomenon. Sensor nodes have advantages for its size, multifunctional, and inexpensive features; unfortunately, the resources are limited in terms of memory, computational, and in energy, especially. Network transmission between nodes and base station (BS) needs to be carefully designed to prolong the network life cycle. As the data transmission is energy consuming compared to data processing, designing sensor nodes into hierarchical network architecture is preferable because it can limit the network transmission. LEACH is one of the hierarchical network protocols known for simple and energy saving protocols. There are lots of modification made since LEACH was introduced for more energy efficient purposed. In this paper, hybridization of LEACH-C and LEACH-R and the modification have been presented for a more energy saving LEACH called LEACH-CR. Experimental result was compared with previous LEACH variant and showed to has advantages over the existing LEACH protocols in terms of energy consumption, dead/alive nodes, and the packet sent to Base Station. The result reflects that the consideration made for residual energy to select the cluster head and proximity transmission lead to a better energy consumption in the network

    Effect of structured use of preoperative portal vein embolization on outcomes after liver resection of perihilar cholangiocarcinoma

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    BACKGROUND: Portal vein embolization (PVE) is performed to reduce the risk of liver failure and subsequent mortality after major liver resection. Although a cut-off value of 2·7 per cent per min per m2 has been used with hepatobiliary scintigraphy (HBS) for future remnant liver function (FRLF), patients with perihilar cholangiocarcinoma (PHC) potentially benefit from an additional cut-off of 8·5 per cent/min (not corrected for body surface area). Since January 2016 a more liberal approach to PVE has been adopted, including this additional cut-off for HBS of 8·5 per cent/min. The aim of this study was to assess the effect of this approach on liver failure and mortality. METHODS: This was a single-centre retrospective study in which consecutive patients undergoing liver resection under suspicion of PHC in 2000-20

    Recent Developments and Applications of the HYDRUS Computer Software Packages

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    The HYDRUS-1D and HYDRUS (2D/3D) computer software packages are widely used finite-element models for simulating the one- and two- or three-dimensional movement of water, heat, and multiple solutes in variably saturated media, respectively. In 2008, Šimůnek et al. (2008b) described the entire history of the development of the various HYDRUS programs and related models and tools such as STANMOD, RETC, ROSETTA, UNSODA, UNSATCHEM, HP1, and others. The objective of this manuscript is to review selected capabilities of HYDRUS that have been implemented since 2008. Our review is not limited to listing additional processes that were implemented in the standard computational modules, but also describes many new standard and nonstandard specialized add-on modules that significantly expanded the capabilities of the two software packages. We also review additional capabilities that have been incorporated into the graphical user interface (GUI) that supports the use of HYDRUS (2D/3D). Another objective of this manuscript is to review selected applications of the HYDRUS models such as evaluation of various irrigation schemes, evaluation of the effects of plant water uptake on groundwater recharge, assessing the transport of particle-like substances in the subsurface, and using the models in conjunction with various geophysical methods

    Lateral opening in the intact β-barrel assembly machinery captured by cryo-EM

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    The β-barrel assembly machinery (BAM) is a ~203 kDa complex of five proteins (BamA-E) which is essential for viability in E. coli. BAM promotes the folding and insertion of β-barrel proteins into the outer membrane via a poorly understood mechanism. Several current models suggest that BAM functions through a ‘lateral gating’ motion of the β-barrel of BamA. Here we present a cryo-EM structure of the BamABCDE complex, at 4.9 Å resolution. The structure is in a laterally open conformation showing that gating is independent of BamB binding. We describe conformational changes throughout the complex, and interactions between BamA, B, D, and E and the detergent micelle that suggest communication between BAM and the lipid bilayer. Finally, using an enhanced reconstitution protocol and functional assays, we show that for the outer membrane protein OmpT, efficient folding in vitro requires lateral gating in BAM

    Outer membrane protein folding from an energy landscape perspective

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    The cell envelope is essential for the survival of Gram-negative bacteria. This specialised membrane is densely packed with outer membrane proteins (OMPs), which perform a variety of functions. How OMPs fold into this crowded environment remains an open question. Here, we review current knowledge about OFMP folding mechanisms in vitro and discuss how the need to fold to a stable native state has shaped their folding energy landscapes. We also highlight the role of chaperones and the β-barrel assembly machinery (BAM) in assisting OMP folding in vivo and discuss proposed mechanisms by which this fascinating machinery may catalyse OMP folding
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