44 research outputs found

    Energy and Link Quality Based Routing for Data Gathering Tree in Wireless Sensor Networks Under TINYOS - 2.X

    Full text link
    Energy is one of the most important and scarce resources in Wireless Sensor Networks (WSN). WSN nodes work with the embedded operating system called TinyOS, which addresses the constrains of the WSN nodes such as limited processing power, memory, energy, etc and it uses the collection Tree Protocol (CTP) to collect the data from the sensor nodes. It uses either the four-bit link estimation or Link Estimation Exchange Protocol (LEEP) to predict the bi directional quality of the wireless link between the nodes and the next hop candidate is based on the estimated link quality. The residual energy of the node is an important key factor, which plays a vital role in the lifetime of the network and hence this has to taken as one of the metric in the parent selection. In this work, we consider the remaining energy of the node as one of the metric to decide the parent in addition to the link quality metrics. The proposed protocol was compared with CTP protocol in terms of number of packets forwarded by each node and packet reception ratio (PRR) of the network. This work was simulated in TOSSIM simulator and the same was tested in Crossbow IRIS radio test bed. The results show that our algorithm performs better than CTP in terms of load distribution and hence the increased lifetimeComment: 14 Pages, IJWM

    Production of mycobacterial cell wall glycopeptidolipids requires a member of the MbtH-like protein family

    Get PDF
    Background Glycopeptidolipids (GPLs) are among the major free glycolipid components of the outer membrane of several saprophytic and clinically-relevant Mycobacterium species. The architecture of GPLs is based on a constant tripeptide-amino alcohol core of nonribosomal peptide synthetase origin that is N-acylated with a 3-hydroxy/methoxy acyl chain synthesized by a polyketide synthase and further decorated with variable glycosylation patterns built from methylated and acetylated sugars. GPLs have been implicated in many aspects of mycobacterial biology, thus highlighting the significance of gaining an understanding of their biosynthesis. Our bioinformatics analysis revealed that every GPL biosynthetic gene cluster known to date contains a gene (referred herein to as gplH) encoding a member of the MbtH-like protein family. Herein, we sought to conclusively establish whether gplH was required for GPL production. Results Deletion of gplH, a gene clustered with nonribosomal peptide synthetase-encoding genes in the GPL biosynthetic gene cluster of Mycobacterium smegmatis, produced a GPL deficient mutant. Transformation of this mutant with a plasmid expressing gplH restored GPL production. Complementation was also achieved by plasmid-based constitutive expression of mbtH, a paralog of gplH found in the biosynthetic gene cluster for production of the siderophore mycobactin of M. smegmatis. Further characterization of the gplH mutant indicated that it also displayed atypical colony morphology, lack of sliding motility, altered capacity for biofilm formation, and increased drug susceptibility. Conclusions Herein, we provide evidence formally establishing that gplH is essential for GPL production in M. smegmatis. Inactivation of gplH also leads to a pleiotropic phenotype likely to arise from alterations in the cell envelope due to the lack of GPLs. While genes encoding MbtH-like proteins have been shown to be needed for production of siderophores and antibiotics, our study presents the first case of one such gene proven to be required for production of a cell wall component. Furthermore, our results provide the first example of a mbtH-like gene with confirmed functional role in a member of the Mycobacterium genus. Altogether, our findings demonstrate a critical role of gplH in mycobacterial biology and advance our understanding of the genetic requirements for the biosynthesis of an important group of constituents of the mycobacterial outer membrane

    Identification and Characterization of a New Orthoreovirus from Patients with Acute Respiratory Infections

    Get PDF
    First discovered in the early 1950s, reoviruses (respiratory enteric orphan viruses) were not associated with any known disease, and hence named orphan viruses. Recently, our group reported the isolation of the Melaka virus from a patient with acute respiratory disease and provided data suggesting that this new orthoreovirus is capable of human-to-human transmission and is probably of bat origin. Here we report yet another Melaka-like reovirus (named Kampar virus) isolated from the throat swab of a 54 year old male patient in Kampar, Perak, Malaysia who was suffering from high fever, acute respiratory disease and vomiting at the time of virus isolation. Serological studies indicated that Kampar virus was transmitted from the index case to at least one other individual and caused respiratory disease in the contact case. Sequence analysis of the four small class genome segments indicated that Kampar and Melaka viruses are closely related. This was confirmed by virus neutralization assay, showing an effective two-way cross neutralization, i.e., the serum against one virus was able to neutralize the other. Although the exact origin of Kampar virus is unknown, epidemiological tracing revealed that the house of the index case is surrounded by fruit trees frequently visited by fruit bats. There is a high probability that Kampar virus originated from bats and was transmitted to humans via bat droppings or contaminated fruits. The discovery of Kampar virus highlights the increasing trend of emergence of bat zoonotic viruses and the need to expand our understanding of bats as a source of many unknown viruses

    Studies on Photocatalytic Degradation of Monocrotophos in an Annular Slurry Reactor Using Factorial Design of Experiments

    No full text
    ABSTRACT Pesticide contamination of natural waters is posing serious threats to water supplies in many parts of the world. Heterogenous photocatalytic Oxidation with TiO 2 photocatalyst is emerging as an attractive technique for pesticide removal. Studies on Monocrotophos (MCP) a widely used pesticide in India, in an annular slurry photoreactor, revealed that the degradation rate is significantly affected by the initial pesticide concentration, pH of the solution and the catalyst concentration. Using a 2 3 central composite factorial design of experiments a quadratic polynomial model was fitted to predict the removal efficiency. The statistical analysis revealed that the coefficients for the main effects are significant. The MCP removals were in the range of 11 to 78 percent depending on the levels of the parameters studied

    Finite element analysis of residual stresses and distortion in hard faced gate valve

    No full text
    129-134This paper studies establishing temperature distribution, distortion and residual stress field developed during plasma arc hard facing of Stellite 6 over low alloy steel (AISI 4140) gate valve by finite element analysis (FEA). In FEA, a three dimensional solid model was generated and simulated using ANSYS parametric design language (APDL) code. After simulation, residual stresses were compared and validated by stress measured by X-Ray diffraction technique. Numerical results showed good agreement with experimental test

    Effect of drought stress on biochemical contents and proline metabolizing enzymes of Pennisetum glaucum L.

    No full text
    Drought stress is one of the major environmental problem affecting agricultural production in arid and semi-arid regions of the world. In present study, the effect of drought stress on Pennisetum glaucum L. (Pearl millet) plants was studied. The seed were sown in plastic pots from 30 days after sowing (DAS). The plants were treated with 3 DID (Days Interval Droughts), 4 DID, 5 DID and 6DID and 30th to 60th DAS. The plants samples were collected from 40th, 50th and 60th DAS. The biochemical like, protein content decreased to increasing drought stress to a larger extent when compared to control plants and also increased the amino acids and proline content to the larger extent with increasing DID when compared to control. The proline metabolizing enzyme like g-glutamyl kinase activity was increased and decreased proline oxidase activity on drought stressed plants

    Effect of drought stress on biochemical contents and proline metabolizing enzymes of Pennisetum glaucum L.

    No full text
    Drought stress is one of the major environmental problem affecting agricultural production in arid and semi-arid regions of the world. In present study, the effect of drought stress on Pennisetum glaucum L. (Pearl millet) plants was studied. The seed were sown in plastic pots from 30 days after sowing (DAS). The plants were treated with 3 DID (Days Interval Droughts), 4 DID, 5 DID and 6DID and 30th to 60th DAS. The plants samples were collected from 40th, 50th and 60th DAS. The biochemical like, protein content decreased to increasing drought stress to a larger extent when compared to control plants and also increased the amino acids and proline content to the larger extent with increasing DID when compared to control. The proline metabolizing enzyme like g-glutamyl kinase activity was increased and decreased proline oxidase activity on drought stressed plants
    corecore