647 research outputs found

    Catalytic surface effects on space thermal protection system during Earth entry of flights STS-2 through STS-5

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    An on going orbiter experiment catalytic surface effects experiment being conducted on the Space Shuttle is discussed. The catalytic surface effects experiment was peformed on four of the five flights of Columbia. Temperature time histories and distributions along the midfuselage and wing of the orbiter were used to determine the surface catalytic efficiency of the baseline high temperature reusable surface insulation. Correlation parameters are shown that allow the comparison of all flight data with predictions from the design and surface emittance decreased as a result of contaminants during the five flights of the Space Shuttle

    Effect of gaseous and solid simulated jet plumes on a 040A space shuttle launch configuration at Mach numbers from 1.6 to 2.2

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    An experimental investigation was conducted in a 9- by 7-foot supersonic wind tunnel to determine the effect of plume-induced flow separation and aspiration effects due to operation of both the orbiter and the solid rocket motors on a 0.019-scale model of the launch configuration of the space shuttle vehicle. Longitudinal and lateral-directional stability data were obtained at Mach numbers of 1.6, 2.0, and 2.2 with and without the engines operating. The plumes exiting from the engines were simulated by a cold gas jet supplied by an auxiliary 200 atmosphere air supply system, and by solid body plume simulators. Comparisons of the aerodynamic effects produced by these two simulation procedures are presented. The data indicate that the parameters most significantly affected by the jet plumes are the pitching moment, the elevon control effectiveness, the axial force, and the orbiter wing loads

    Separation Dynamics of Multibody Clusters of Hinged and/or Linked Lifting-Entry Vehicles

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    A digital simulation has been developed to compute the kinematics of separation of as many as five auxiliary (boost) elements attached around the periphery of a central core (orbital) element in six rigid-body degrees of freedom for the core and three rigid-body degrees of freedom for each attached auxiliary element. Once separated, all vehicles have six degrees of freedom. All vehicles are assumed to be lifting-entry vehicles and calculations include the aerodynamic properties of both auxiliary and core elements, in addition to the aerodynamic interference obtained from wind tunnel tests. Several separation mechanism options, such as rear pivot, linkages, and lateral thrusters are provided

    Erectile dysfunction in men with chronic obstructive pulmonary disease.

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    Erectile dysfunction (ED) seems to be a widespread sexual issue in men affected by chronic obstructive pulmonary disease (COPD). Multiple causes appear to be involved such as hormonal imbalance, smoking habit, chronic inflammation, endothelial dysfunction, chronic hypoxia, psychiatric disorders (depression and anxiety), and medications. ED can have a significant impact on COPD men and consequently on their quality of life, which is usually already compromised. Given this situation, however, pneumologists usually do not properly care for the sexuality of COPD patients especially because men can be reluctant to talk about their intimate issues. The aim of this narrative review is to briefly summarize the evidence emerging from literature and to provide a wide point of view about sexual dysfunction in COPD men

    Editorial: Interactions of Plants With Bacteria and Fungi: Molecular and Epigenetic Plasticity of the Host

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    Editorial on the Research Topic 'Interactions of Plants with Bacteria and Fungi: Molecular and Epigenetic Plasticity of the Host

    Arbuscular Mycorrhizal Symbiosis Limits Foliar Transcriptional Responses to Viral Infection and Favors Long-Term Virus Accumulation

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    Tomato (Solanum lycopersicum) can establish symbiotic interactions with arbuscular mycorrhizal (AM) fungi, and can be infected by several pathogenic viruses. Here, we investigated the impact of mycorrhization by the fungus Glomus mosseae on the Tomato spotted wilt virus (TSWV) infection of tomato plants by transcriptomic and hormones level analyses. In TSWV-infected mycorrhizal plants, the AM fungus root colonization limited virus-induced changes in gene expression in the aerial parts. The virus-responsive upregulated genes, no longer induced in infected mycorrhizal plants, were mainly involved in defense responses and hormone signaling, while the virus-responsive downregulated genes, no longer repressed in mycorrhizal plants, were involved in primary metabolism. The presence of the AM fungus limits, in a salicylic acid-independent manner, the accumulation of abscissic acid observed in response to viral infection. At the time of the molecular analysis, no differences in virus concentration or symptom severity were detected between mycorrhizal and nonmycorrhizal plants. However, in a longer period, increase in virus titer and delay in the appearance of recovery were observed in mycorrhizal plants, thus indicating that the plant's reaction to TSWV infection is attenuated by mycorrhization. </jats:p

    Biochemical and nutritional traits of sea bass (Dicentrachus labrax) from different rearing systems.

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    Farmed European sea bass (Dicentrarchus labrax), sampled from three different culture systems (intensive in sea-cages, intensive in land-based basins and extensive in lagoon and storage basins of salt-work), of the Northern, Central and Southern Italy, were analyzed with the aim to employ nutritional trait to describe and to distinguish the "origin" of the product. Lipid and fatty acid profile, strongly affected by the feeding history and environmental factors, responsible of the nu- tritional and perceived quality of fish product, are proposed as marker of origin

    Gigaspora margarita and its endobacterium modulate symbiotic marker genes in tomato roots under combined water and nutrient stress

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    As members of the plant microbiota, arbuscular mycorrhizal fungi (AMF) may be effective in enhancing plant resilience to drought, one of the major limiting factors threatening crop productivity. AMF host their own microbiota and previous data demonstrated that endobacteria thriving in Gigaspora margarita modulate fungal antioxidant responses. Here, we used the G. margarita–Candidatus Glomeribacter gigasporarum system to test whether the tripartite interaction between tomato, G. margarita and its endobacteria may improve plant resilience to combined water/nutrient stress. Tomato plants were inoculated with spores containing endobacteria (B+) or not (B−), and exposed to combined water/nutrient stress. Plants traits, AM colonization and expression of AM marker genes were measured. Results showed that mycorrhizal frequency was low and no growth effect was observed. Under control conditions, B+ inoculated plants were more responsive to the symbiosis, as they showed an up-regulation of three AM marker genes involved in phosphate and lipids metabolism compared with B− inoculated or not-inoculated plants. When combined stress was imposed, the difference between fungal strains was still evident for one marker gene. These results indicate that the fungal endobacteria finely modulate plant metabolism, even in the absence of growth response

    Pseudo-outbreak of Mycobacterium gordonae in a teaching hospital: importance of strictly following decontamination procedures and emerging issues concerning sterilization

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    Aim of this study was to investigate a pseudo-outbreak of Mycobacterium gordonae analyzing isolates detected from clinical and environmental samples. Mycobacterium gordonae was detected in 7 out of 497 broncho-alveolar lavage (BAL) samples after bronchoscopy procedure in patients admitted to a teaching hospital between January and April 2013. During this pseudo-outbreak clinical, epidemiological, environmental and molecular investigations were performed. None of the patients met the criteria for non-tuberculous mycobacterial (NTM) lung disease and were treated for M. gordonae lung disease. Environmental investigation revealed M. gordonae in 3 samples: in tap water and in the water supply channel of the washer disinfector. All the isolates were subjected to genotyping by pulsed-field gel electrophoresis (PFGE). The PFGE revealed that only patients' isolates presented the same band pattern but no correlation with the environmental strain was detected. Surveillance of the outbreak and the strict adherence to the reprocessing procedure and its supplies resulted afterwards in no detection of M. gordonae in clinical respiratory samples. Clinical surveillance of patients was crucial to establish the start of NTM treatment. Regular screening of tap water and endoscopic equipment should be adopted to compare the clinical strains with the environmental ones when an outbreak occurs
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