141 research outputs found

    Influence of food system conditions on N-acyl-L-homoserine lactones production by <i>Aeromonas</i> spp.

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    Eleven of 13 Aeromonas strains were shown to produce AHLs. Results of TLC showed that N-butanoyl-L-homoserine lactone (C4-HSL) was the main AHL produced in LB medium at 30 degrees C. The influence of different carbon sources, temperature, pH values and salt concentrations on AHL production was determined in eight A. hydrophila and one A. caviae strain. Additionally a quantitative study of C4-HSL production by A. hydrophila strain 519 under different conditions was performed. Positive results were found in the AHL induction assay for some Aeromonas strains in cultures in LB agar incubated at 12 degrees C after 72-96 h. The induction of the sensor strains by Aeromonas spp. occurred in LB medium supplemented with all carbon sources in a concentration of 0.5%. The production of C4-HSL by A. hydrophila 519 was found until 3.5% (w/v) of NaCl. For pHs close to the neutrality the C4-HSL production by A. hydrophila was evident after 24-48 h of incubation. A. hydrophila 519 produced C4-HSL under anaerobic conditions. Also, the AHL production by Aeromonas strains was studied in simulate agar of shrimp, fish and some vegetables. The production of AHLs was evident by almost all the test strains in shrimp simulated agar. In fish agar only for one of three fish species tested, positive results were found. Induction assay in vegetables simulated agar showed principally negative results, probably because of the presence of inhibitory compounds in these vegetables

    Microalgae biorefinery alternatives and hazard evaluation

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    Biodiesel production based on microalgae and using carbon dioxide as feedstock constitutes an attractive biofuel alternative. Technology development and process optimization are necessary to minimize the overall production cost. Moreover, in the framework of process sustainability, social and environmental impacts should include process safety aspects. In this context, the objective of this work is to develop a biodiesel production process based on microalgae and the subsequent estimation of the associated risks, thus contributing to more sustainable and safe processes. The biodiesel biorefinery is optimized, taking into account alternative configurations for algae cultivation and lipid extraction. Algae cultivation options are open ponds and tubular photobioreactors. Regarding lipid extraction, dewatering and subsequent n-hexane extraction, and combined ethanol/n-hexane extraction are the studied alternatives. Numerical results showed that open ponds and n-hexane extraction provide maximum net present value. However, n-hexane consumption dramatically rises, and industrial hazards have not been considered in the optimization process. To overcome this issue, a preliminary hazard analysis is carried out to identify hazardous materials and operations. Event trees are formulated to derive the frequencies of different accident scenarios, further determining the consequences. The major consequences of accidents involve toxic releases of high quantities of n-hexane. By comparing the proposed alternatives, this work aims to highlight the need to consider not only economic but also safety and environmental objectives in the development of a biodiesel production project.The authors are grateful for the financial support provided by CONICET and the Spanish MICINN under projects CTQ2013-48280-C3-1-R and CTM2014-57833-R. J. Pinedo would also like to thank the financial support provided by “Becas Iberoamérica JPI España 2014”

    Anisotropy studies around the galactic centre at EeV energies with the Auger Observatory

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    Data from the Pierre Auger Observatory are analyzed to search for anisotropies near the direction of the Galactic Centre at EeV energies. The exposure of the surface array in this part of the sky is already significantly larger than that of the fore-runner experiments. Our results do not support previous findings of localized excesses in the AGASA and SUGAR data. We set an upper bound on a point-like flux of cosmic rays arriving from the Galactic Centre which excludes several scenarios predicting sources of EeV neutrons from Sagittarius AA. Also the events detected simultaneously by the surface and fluorescence detectors (the `hybrid' data set), which have better pointing accuracy but are less numerous than those of the surface array alone, do not show any significant localized excess from this direction.Comment: Matches published versio

    Evidence for a mixed mass composition at the `ankle' in the cosmic-ray spectrum

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    We report a first measurement for ultra-high energy cosmic rays of the correlation between the depth of shower maximum and the signal in the water Cherenkov stations of air-showers registered simultaneously by the fluorescence and the surface detectors of the Pierre Auger Observatory. Such a correlation measurement is a unique feature of a hybrid air-shower observatory with sensitivity to both the electromagnetic and muonic components. It allows an accurate determination of the spread of primary masses in the cosmic-ray flux. Up till now, constraints on the spread of primary masses have been dominated by systematic uncertainties. The present correlation measurement is not affected by systematics in the measurement of the depth of shower maximum or the signal in the water Cherenkov stations. The analysis relies on general characteristics of air showers and is thus robust also with respect to uncertainties in hadronic event generators. The observed correlation in the energy range around the `ankle' at lg(E/eV)=18.519.0\lg(E/{\rm eV})=18.5-19.0 differs significantly from expectations for pure primary cosmic-ray compositions. A light composition made up of proton and helium only is equally inconsistent with observations. The data are explained well by a mixed composition including nuclei with mass A>4A > 4. Scenarios such as the proton dip model, with almost pure compositions, are thus disfavoured as the sole explanation of the ultrahigh-energy cosmic-ray flux at Earth.Comment: Published version. Added journal reference and DOI. Added Report Numbe

    Assessment of plasma chitotriosidase activity, CCL18/PARC concentration and NP-C suspicion index in the diagnosis of Niemann-Pick disease type C: A prospective observational study

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    Background: Niemann-Pick disease type C (NP-C) is a rare, autosomal recessive neurodegenerative disease caused by mutations in either the NPC1 or NPC2 genes. The diagnosis of NP-C remains challenging due to the non-specific, heterogeneous nature of signs/symptoms. This study assessed the utility of plasma chitotriosidase (ChT) and Chemokine (C-C motif) ligand 18 (CCL18)/pulmonary and activation-regulated chemokine (PARC) in conjunction with the NP-C suspicion index (NP-C SI) for guiding confirmatory laboratory testing in patients with suspected NP-C. Methods: In a prospective observational cohort study, incorporating a retrospective determination of NP-C SI scores, two different diagnostic approaches were applied in two separate groups of unrelated patients from 51 Spanish medical centers (n = 118 in both groups). From Jan 2010 to Apr 2012 (Period 1), patients with =2 clinical signs/symptoms of NP-C were considered ''suspected NP-C'' cases, and NPC1/NPC2 sequencing, plasma chitotriosidase (ChT), CCL18/PARC and sphingomyelinase levels were assessed. Based on findings in Period 1, plasma ChT and CCL18/PARC, and NP-C SI prediction scores were determined in a second group of patients between May 2012 and Apr 2014 (Period 2), and NPC1 and NPC2 were sequenced only in those with elevated ChT and/or elevated CCL18/PARC and/or NP-C SI =70. Filipin staining and 7-ketocholesterol (7-KC) measurements were performed in all patients with NP-C gene mutations, where possible. Results: In total across Periods 1 and 2, 10/236 (4%) patients had a confirmed diagnosis o NP-C based on gene sequencing (5/118 4.2%] in each Period): all of these patients had two causal NPC1 mutations. Single mutant NPC1 alleles were detected in 8/236 (3%) patients, overall. Positive filipin staining results comprised three classical and five variant biochemical phenotypes. No NPC2 mutations were detected. All patients with NPC1 mutations had high ChT activity, high CCL18/PARC concentrations and/or NP-C SI scores =70. Plasma 7-KC was higher than control cut-off values in all patients with two NPC1 mutations, and in the majority of patients with single mutations. Family studies identified three further NP-C patients. Conclusion: This approach may be very useful for laboratories that do not have mass spectrometry facilities and therefore, they cannot use other NP-C biomarkers for diagnosis

    Definition, aims, and implementation of GA2LEN/HAEi Angioedema Centers of Reference and Excellence

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    The rapid atmospheric monitoring system of the Pierre Auger Observatory

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    The Pierre Auger Observatory is a facility built to detect air showers produced by cosmic rays above 10(17) eV. During clear nights with a low illuminated moon fraction, the UV fluorescence light produced by air showers is recorded by optical telescopes at the Observatory. To correct the observations for variations in atmospheric conditions, atmospheric monitoring is performed at regular intervals ranging from several minutes (for cloud identification) to several hours (for aerosol conditions) to several days (for vertical profiles of temperature, pressure, and humidity). In 2009, the monitoring program was upgraded to allow for additional targeted measurements of atmospheric conditions shortly after the detection of air showers of special interest, e. g., showers produced by very high-energy cosmic rays or showers with atypical longitudinal profiles. The former events are of particular importance for the determination of the energy scale of the Observatory, and the latter are characteristic of unusual air shower physics or exotic primary particle types. The purpose of targeted (or 'rapid') monitoring is to improve the resolution of the atmospheric measurements for such events. In this paper, we report on the implementation of the rapid monitoring program and its current status. The rapid monitoring data have been analyzed and applied to the reconstruction of air showers of high interest, and indicate that the air fluorescence measurements affected by clouds and aerosols are effectively corrected using measurements from the regular atmospheric monitoring program. We find that the rapid monitoring program has potential for supporting dedicated physics analyses beyond the standard event reconstruction

    Depth Of Maximum Of Air-shower Profiles At The Pierre Auger Observatory. I. Measurements At Energies Above 1017.8ev

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    Autoantibodies against type I IFNs in patients with life-threatening COVID-19

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    Interindividual clinical variability in the course of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is vast. We report that at least 101 of 987 patients with life-threatening coronavirus disease 2019 (COVID-19) pneumonia had neutralizing immunoglobulin G (IgG) autoantibodies (auto-Abs) against interferon-w (IFN-w) (13 patients), against the 13 types of IFN-a (36), or against both (52) at the onset of critical disease; a few also had auto-Abs against the other three type I IFNs. The auto-Abs neutralize the ability of the corresponding type I IFNs to block SARS-CoV-2 infection in vitro. These auto-Abs were not found in 663 individuals with asymptomatic or mild SARS-CoV-2 infection and were present in only 4 of 1227 healthy individuals. Patients with auto-Abs were aged 25 to 87 years and 95 of the 101 were men. A B cell autoimmune phenocopy of inborn errors of type I IFN immunity accounts for life-threatening COVID-19 pneumonia in at least 2.6% of women and 12.5% of men

    Techniques for measuring aerosol attenuation using the Central Laser Facility at the Pierre Auger Observatory

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    The Pierre Auger Observatory in Malargüe, Argentina, is designed to study the properties of ultra-high energy cosmic rays with energies above 10(18) eV. It is a hybrid facility that employs a Fluorescence Detector to perform nearly calorimetric measurements of Extensive Air Shower energies. To obtain reliable calorimetric information from the FD, the atmospheric conditions at the observatory need to be continuously monitored during data acquisition. In particular, light attenuation due to aerosols is an important atmospheric correction. The aerosol concentration is highly variable, so that the aerosol attenuation needs to be evaluated hourly. We use light from the Central Laser Facility, located near the center of the observatory site, having an optical signature comparable to that of the highest energy showers detected by the FD. This paper presents two procedures developed to retrieve the aerosol attenuation of fluorescence light from CLF laser shots. Cross checks between the two methods demonstrate that results from both analyses are compatible, and that the uncertainties are well understood. The measurements of the aerosol attenuation provided by the two procedures are currently used at the Pierre Auger Observatory to reconstruct air shower data
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