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Schaible B.,University College Dublin | Schaible B.,Queenss University | McClean S.,Institute of Technology Tallaght | Selfridge A.,University College Dublin | And 4 more authors.
PLoS ONE | Year: 2013

Pseudomonas aeruginosa (P. aeruginosa) is an opportunistic pathogen commonly associated with lung and wound infections. Hypoxia is a frequent feature of the microenvironment of infected tissues which induces the expression of genes associated with innate immunity and inflammation in host cells primarily through the activation of the hypoxia-inducible factor (HIF) and Nuclear factor kappaB (NF-κB) pathways which are regulated by oxygen-dependent prolyl-hydroxylases. Hypoxia also affects virulence and antibiotic resistance in bacterial pathogens. However, less is known about the impact of hypoxia on host-pathogen interactions such as bacterial adhesion and infection. In the current study, we demonstrate that hypoxia decreases the internalization of P. aeruginosa into cultured epithelial cells resulting in decreased host cell death. This response can also be elicited by the hydroxylase inhibitor Dimethyloxallyl Glycine (DMOG). Reducing HIF-2α expression or Rho kinase activity diminished the effects of hypoxia on P. aeruginosa infection. Furthermore, in an in vivo pneumonia infection model, application of DMOG 48 h before infection with P. aeruginosa significantly reduced mortality. Thus, hypoxia reduces P. aeruginosa internalization into epithelial cells and pharmacologic manipulation of the host pathways involved may represent new therapeutic targets in the treatment of P. aeruginosa infection. © 2013 Schaible et al.

Abdelal G.F.,Queenss University | Robotham A.,Auckland University of Technology | Carragher P.,United Technologies
Journal of Petroleum Science and Engineering | Year: 2015

For over 50 years bridge plugs and cement have been used for well abandonment, work over, and are still the material of choice. However the failures of cement abandonments using bridge plugs has been reported on many occasions, some of which have resulted in fatal consequences. A new patented product is designed to address the shortcomings associated with using bridge plugs and cement. The new developed tools use an alloy based on bismuth that is melted in situ using Thermite reaction. The tool uses the expansion properties of bismuth to seal the well. Testing the new technology in real field under more than 2. km deep sea water can be expensive. Virtual simulation of the new device under simulated thermal and mechanical environment can be achieved using nonlinear finite element method to validate the product and reduce cost. Experimental testing in the lab is performed to measure heat generated due to thermite reaction. Then, a sequential thermal mechanical explicit/implicit finite element solver is used to simulate the device under both testing lab and deep water conditions. © 2015 Elsevier B.V.

Hanshi S.M.,Universiti Sains Malaysia | Kadhum M.M.,Universiti Sains Malaysia | Kadhum M.M.,Queenss University
2013 IEEE International Conference on RFID-Technologies and Applications, RFID-TA 2013 | Year: 2013

Due to high mobility and nature of vehicular adhoc environment, routing decisions in such a network are becoming a hard task. Therefore, the routing protocol must be robust to frequent link disruptions and aware of the environment surrounding the network. It is noticeable that routing-based position protocols are more appropriate for high dynamic and fast topology change networks. Many routing protocols have been proposed to enhance the delivery of data packets in a vehicular network. The goal of this paper is to review the current position-based routing protocols, in order to get more insight on the capability of these routing protocols in handling different challenges of vehicular ad-hoc networks. © 2013 IEEE.

Khudayer B.,Al-Buraimi University College | Kadhum M.,Universiti Sains Malaysia | Kadhum M.,Queenss University
Proceedings - IEEE COMNETSAT 2014: 2014 IEEE International Conference on Communication, Network and Satellite | Year: 2014

Mobile Ad Hoc Networks (MANETs) are increasingly being used in various applications for civilian, commercial, and military uses. However, unique characteristics of MANETs introduce several challenges such as routing and mobility management. Nodes frequent movements make routing more difficult due to frequent topology changes. Dynamic Source Routing (DSR) routing protocol is among the common routing protocols that suffer from poor performance in highly dynamic environment. This paper presents an extensive study of the performance of DSR in heterogeneous scalable MANET that involves different nodes with different resources where no prior information about the destinations is available. The study shows that DSR performance suffers significantly over heterogeneous MANETs with respect to network sizes and resources. © 2014 IEEE.

Zastrau U.,Friedrich - Schiller University of Jena | Zastrau U.,Helmholtz Center for Heavy Ion Research | Vinko S.M.,University of Oxford | Wark J.S.,University of Oxford | And 11 more authors.
AIP Conference Proceedings | Year: 2012

We report on experiments aimed at the generation and characterization of solid density plasmas at the free-electron laser FLASH in Hamburg. Aluminum samples were irradiated with XUV pulses at 13.5 nm wavelength (92 eV photon energy). The pulses with duration of a few tens of femtoseconds and pulse energy up to 100 μJ are focused to intensities ranging from 10 13 to 10 17 W/cm 2. We investigate the absorption and temporal evolution of the sample under irradiation by use of XUV spectroscopy. We discuss the origin of saturable absorption, radiative decay, bremsstrahlung and ionic line emission. Our experimental results are in good agreement with hydrodynamic simulations. © 2012 American Institute of Physics.

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