510 research outputs found

    The Equation of State for QCD with 2+1 Flavors of Quarks

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    We report results for the interaction measure, pressure and energy density for nonzero temperature QCD with 2+1 flavors of improved staggered quarks. In our simulations we use a Symanzik improved gauge action and the Asqtad O(a2)O(a^2) improved staggered quark action for lattices with temporal extent Nt=4N_t=4 and 6. The heavy quark mass msm_s is fixed at approximately the physical strange quark mass and the two degenerate light quarks have masses mud=0.1msm_{ud} =0.1m_s or 0.2ms0.2m_s. The calculation of the thermodynamic observables employs the integral method where energy density and pressure are obtained by integration over the interaction measure.Comment: 6 pages, 1 figure, 3 tables, contribution to the XXIIIrd International Symposium on Lattice Field Theory, 25-30 July 2005, Trinity College, Dublin, Irelan

    Pressure Modulator Radiometer (PMR) tests

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    The pressure modulator technique was evaluated for monitoring pollutant gases in the Earth's atmosphere of altitude levels corresponding to the mid and lower troposphere. Using an experimental set up and a 110 cm sample cell, pressure modulator output signals resulting from a range of gas concentrations in the sample cell were examined. Then a 20 cm sample cell was modified so that trace gas properties in the atmosphere could be simulated in the laboratory. These gas properties were measured using an infrared sensor

    Revisiting the martensite/ferrite interface damage initiation mechanism:The key role of substructure boundary sliding

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    Martensite/ferrite (M/F) interface damage plays a critical role in controlling failure of dual-phase (DP) steels and is commonly understood to originate from the large phase contrast between martensite and ferrite. This however conflicts with a few, recent observations, showing that considerable M/F interface damage initiation is often accompanied by apparent martensite island plasticity and weak M/F strain partitioning. In fact, martensite has a complex hierarchical structure which induces a strongly heterogeneous and orientation-dependent plastic response. Depending on the local stress state, (lath) martensite is presumed to be hard to deform based on common understanding. However, when favourably oriented, substructure boundary sliding can be triggered at a resolved shear stress which is comparable to that of ferrite. Moreover, careful measurements of the M/F interface structure indicate the occurrence of sharp martensite wedges protruding into the ferrite and clear steps in correspondence with lath boundaries, constituting a jagged M/F interfacial morphology that may have a large effect on the M/F interface behaviour. By taking into account the substructure and morphology features, which are usually overlooked in the literature, this contribution re-examines the M/F interface damage initiation mechanism. A systematic study is performed, which accounts for different loading conditions, phase contrasts, residual stresses/strains resulting from the preceding martensitic phase transformation, as well as the possible M/F interfacial morphologies. Crystal plasticity simulations are conducted to include inter-lath retained austenite (RA) films enabling the substructure boundary sliding. The results show that the substructure boundary sliding, which is the most favourable plastic deformation mode of lath martensite, can trigger M/F interface damage and hence control the failure behaviour of DP steels. The present finding may change the way in which M/F interface damage initiation is understood as a critical failure mechanism in DP steels

    The Mycotoxin Deoxynivalenol Potentiates Intestinal Inflammation by Salmonella Typhimurium in Porcine Ileal Loops

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    Background and Aims: Both deoxynivalenol (DON) and nontyphoidal salmonellosis are emerging threats with possible hazardous effects on both human and animal health. The objective of this study was to examine whether DON at low but relevant concentrations interacts with the intestinal inflammation induced by Salmonella Typhimurium. Methodology: By using a porcine intestinal ileal loop model, we investigated whether intake of low concentrations of DON interacts with the early intestinal inflammatory response induced by Salmonella Typhimurium. Results: A significant higher expression of IL-12 and TNF alpha and a clear potentiation of the expression of IL-1 beta, IL-8, MCP-1 and IL-6 was seen in loops co-exposed to 1 mu g/mL of DON and Salmonella Typhimurium compared to loops exposed to Salmonella Typhimurium alone. This potentiation coincided with a significantly enhanced Salmonella invasion in and translocation over the intestinal epithelial IPEC-J2 cells, exposed to non-cytotoxic concentrations of DON for 24 h. Exposure of Salmonella Typhimurium to 0.250 mu g/mL of DON affected the bacterial gene expression level of a limited number of genes, however none of these expression changes seemed to give an explanation for the increased invasion and translocation of Salmonella Typhimurium and the potentiated inflammatory response in combination with DON. Conclusion: These data imply that the intake of low and relevant concentrations of DON renders the intestinal epithelium more susceptible to Salmonella Typhimurium with a subsequent potentiation of the inflammatory response in the gut

    A seismic array on Mt. Vesuvius

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    In November 1997 a seismic antenna (array) of short period seismometers was installed on the south-western flank of Mt. Vesuvius; aim of the experiment was to test the use of non-conventional devices for the seismic monitoring of this volcano. In 7 months local seismicity, regional earthquakes and samples of seismic noise were recorded by the array and organised in a data base. Local earthquakes and seismic noise have been analysed with array techniques to investigate the spectral, kinematic and polarization properties of the wavefield. Preliminary results show that the backazimuth of local earthquakes is oriented in the direction of the crater area. For some events, the source location has been constrained using a simplified back propagation in a 2-D velocity structure. The noise wavefield is characterized by the predominance of a sustained low frequency component (< 1Hz) whose source is located S-SE of the array. This low frequency signal has been interpreted as associated to the sea-loading in the gulf of Naples.Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio VesuvianoPublished1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attiveope

    A seismic array on Mt. Vesuvius

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    In November 1997 a seismic antenna (array) of short period seismometers was installed on the south-western flank of Mt. Vesuvius; aim of the experiment was to test the use of non-conventional devices for the seismic monitoring of this volcano. In 7 months local seismicity, regional earthquakes and samples of seismic noise were recorded by the array and organised in a data base. Local earthquakes and seismic noise have been analysed with array techniques to investigate the spectral, kinematic and polarization properties of the wavefield. Preliminary results show that the backazimuth of local earthquakes is oriented in the direction of the crater area. For some events, the source location has been constrained using a simplified back propagation in a 2-D velocity structure. The noise wavefield is characterized by the predominance of a sustained low frequency component (< 1Hz) whose source is located S-SE of the array. This low frequency signal has been interpreted as associated to the sea-loading in the gulf of Naples

    Sphingopyxis Species Isolated from Sand Filter Biofilm at an Australian Drinking Water Treatment Works

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    Three strains isolated by geosmin enrichment from a sand filter in an Australian drinking water treatment works were genome sequenced to identify their taxonomic placement, and a bench-scale batch experiment confirmed their geosmin-degrading capability. Using the average nucleotide identity based on the MUMmer algorithm (ANIm), pairwise digital DNA-DNA hybridization (dDDH), and phylogenomic analyses, the strains were identified as Sphingopyxis species

    The rumen microbiome:An underexplored resource for novel antimicrobial discovery

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    Antimicrobial peptides (AMPs) are promising drug candidates to target multi-drug resistant bacteria. The rumen microbiome presents an underexplored resource for the discovery of novel microbial enzymes and metabolites, including AMPs. Using functional screening and computational approaches, we identified 181 potentially novel AMPs from a rumen bacterial metagenome. Here, we show that three of the selected AMPs (Lynronne-1, Lynronne-2 and Lynronne-3) were effective against numerous bacterial pathogens, including methicillin-resistant Staphylococcus aureus (MRSA). No decrease in MRSA susceptibility was observed after 25 days of sub-lethal exposure to these AMPs. The AMPs bound preferentially to bacterial membrane lipids and induced membrane permeability leading to cytoplasmic leakage. Topical administration of Lynronne-1 (10% w/v) to a mouse model of MRSA wound infection elicited a significant reduction in bacterial counts, which was comparable to treatment with 2% mupirocin ointment. Our findings indicate that the rumen microbiome may provide viable alternative antimicrobials for future therapeutic applicationpublishersversionPeer reviewe

    Vulnerability of Polarised Intestinal Porcine Epithelial Cells to Mycotoxin Deoxynivalenol Depends on the Route of Application

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    BACKGROUND AND AIMS: Deoxynivalenol (DON) is a Fusarium derived mycotoxin, often occurring on cereals used for human and animal nutrition. The intestine, as prominent barrier for nutritional toxins, has to handle the mycotoxin from the mucosa protected luminal side (apical exposure), as well as already absorbed toxin, reaching the cells from basolateral side via the blood stream. In the present study, the impact of the direction of DON exposure on epithelial cell behaviour and intestinal barrier integrity was elucidated. METHODS: A non-transformed intestinal porcine epithelial cell line (IPEC-J2), cultured in membrane inserts, serving as a polarised in vitro model to determine the effects of deoxynivalenol (DON) on cellular viability and tight junction integrity. RESULTS: Application of DON in concentrations up to 4000 ng/mL for 24, 48 and 72 hours on the basolateral side of membrane cultured polarised IPEC-J2 cells resulted in a breakdown of the integrity of cell connections measured by transepithelial electrical resistance (TEER), as well as a reduced expression of the tight junction proteins ZO-1 and claudin 3. Epithelial cell number decreased and nuclei size was enlarged after 72 h incubation of 4000 ng/mL DON from basolateral. Although necrosis or caspase 3 mediated apoptosis was not detectable after basolateral DON application, cell cycle analysis revealed a significant increase in DNA fragmentation, decrease in G0/G1 phase and slight increase in G2/M phase after 72 hours incubation with DON 2000 ng/mL. CONCLUSIONS: Severity of impact of the mycotoxin deoxynivalenol on the intestinal epithelial barrier is dependent on route of application. The epithelium appears to be rather resistant towards apical (luminal) DON application whereas the same toxin dose from basolateral severely undermines barrier integrity
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