765 research outputs found
Granulocyte-derived extracellular vesicles activate monocytes and are associated with mortality in intensive care unit patients
Greenpeace cyberadvocacy: message strategies and the framing of the say no to genetic engineering campaign
A content analysis was conducted to examine campaign message characteristics and the framing of genetic engineering (GE) in news articles published in sites dedicated to two countries with different policy stances toward GE---Australia (precautionary) and Philippines (permissive).;The findings show the intent to generate awareness and encourage information seeking among audiences. Logical reasoning that highlighted risks using negative appeals indicate latent and aware publics as target audiences. The Australian and Philippine sites showed spikes in news items published preceding the commercial release of GM crops. In both countries, biotechnology policy was the most dominant frame used. The Philippines used significantly more frames and sources in longer articles
Characterization of Pro-Inflammatory Flagellin Proteins Produced by Lactobacillus ruminis and Related Motile Lactobacilli
peer-reviewedLactobacillus ruminis is one of at least twelve motile but poorly characterized species found in the genus Lactobacillus. Of these, only L. ruminis has been isolated from mammals, and this species may be considered as an autochthonous member of the gastrointestinal microbiota of humans, pigs and cows. Nine L. ruminis strains were investigated here to elucidate the biochemistry and genetics of Lactobacillus motility. Six strains isolated from humans were non-motile while three bovine isolates were motile. A complete set of flagellum biogenesis genes was annotated in the sequenced genomes of two strains, ATCC25644 (human isolate) and ATCC27782 (bovine isolate), but only the latter strain produced flagella. Comparison of the L. ruminis and L. mali DSM20444T motility loci showed that their genetic content and gene-order were broadly similar, although the L. mali motility locus was interrupted by an 11.8 Kb region encoding rhamnose utilization genes that is absent from the L. ruminis motility locus. Phylogenetic analysis of 39 motile bacteria indicated that Lactobacillus motility genes were most closely related to those of motile carnobacteria and enterococci. Transcriptome analysis revealed that motility genes were transcribed at a significantly higher level in motile L. ruminis ATCC27782 than in non-motile ATCC25644. Flagellin proteins were isolated from L. ruminis ATCC27782 and from three other Lactobacillus species, while recombinant flagellin of aflagellate L. ruminis ATCC25644 was expressed and purified from E. coli. These native and recombinant Lactobacillus flagellins, and also flagellate L. ruminis cells, triggered interleukin-8 production in cultured human intestinal epithelial cells in a manner suppressed by short interfering RNA directed against Toll-Like Receptor 5. This study provides genetic, transcriptomic, phylogenetic and immunological insights into the trait of flagellum-mediated motility in the lactobacilli.This work was supported by a Principal Investigator Award (07/IN.1/B1780) from Science Foundation Ireland to PWOT. BAN was the recipient of an Embark studentship from the Irish Research Council for Science Engineering and Technology. TD and KN were supported by the Alimentary Pharmabiotic Centre, funded by Science Foundation Ireland
Identification of plastic constitutive parameters at large deformations from three dimensional displacement fields
The aim of this paper is to provide a general procedure to extract the constitutive parameters of a plasticity model starting from displacement measurements and using the Virtual Fields Method. This is a classical inverse problem which has been already investigated in the literature, however several new features are developed here. First of all the procedure applies to a general three-dimensional displacement field which leads to large plastic deformations, no assumptions are made such as plane stress or plane strain although only pressure-independent plasticity is considered. Moreover the equilibrium equation is written in terms of the deviatoric stress tensor that can be directly computed from the strain field without iterations. Thanks to this, the identification routine is much faster compared to other inverse methods such as finite element updating. The proposed method can be a valid tool to study complex phenomena which involve severe plastic deformation and where the state of stress is completely triaxial, e.g. strain localization or necking occurrence. The procedure has been validated using a three dimensional displacement field obtained from a simulated experiment. The main potentialities as well as a first sensitivity study on the influence of measurement errors are illustrated
Experimental Behavior of Sulfur Under Primitive Planetary Differentiation Processes, the Sulfide Formations in Enstatite Meteorites and Implications for Mercury.
Enstatite meteorites are the most reduced naturally-occuring materials of the solar system. The cubic monosulfide series with the general formula (Mg,Mn,Ca,Fe)S are common phases in these meteorite groups. The importance of such minerals, their formation, composition and textural relationships for understanding the genesis of enstatite chondrites (EC) and aubrites, has long been recognized (e.g. [1]). However, the mechanisms of formation of these sulfides is still not well constrained certainly because of possible multiple ways to produce them. We propose to simulate different models of formation in order to check their mineralogical, chemical and textural relevancies. The solubility of sulfur in silicate melts is of primary interest for planetary mantles, particularly for the Earth and Mercury. Indeed, these two planets could have formed, at least partly, from EC materials (e.g. [2, 3, 4]). The sulfur content in silicate melts depends on the melt composition but also on pressure (P), temperature (T) and oxygen fugacity fO2. Unfortunately, there is no model of general validity in a wide range of P-T-fO2-composition which describes precisely the evolution of sulfur content in silicate melts, even if the main trends are now known. The second goal of this study is to constrain the sulfur content in silicate melts under reducing conditions and different temperatures
Mechanics-driven mechanobiological mechanisms of arterial tortuosity
[EN] Arterial tortuosity manifests in many conditions, including hypertension, genetic mutations predisposing to thoracic aortopathy, and vascular aging. Despite evidence that tortuosity disrupts efficient blood flow and that it may be an important clinical biomarker, underlying mechanisms remain poorly understood but are widely appreciated to be largely biomechanical. Many previous studies suggested that tortuosity may arise via an elastic structural buckling instability, but the novel experimental-computational approach used here suggests that tortuosity arises from mechanosensitive, cell-mediated responses to local aberrations in the microstructural integrity of the arterial wall. In particular, computations informed by multimodality imaging show that aberrations in elastic fiber integrity, collagen alignment, and collagen turnover can lead to a progressive loss of structural stability that entrenches during the development of tortuosity. Interpreted in this way, microstructural defects or irregularities of the arterial wall initiate the condition and hypertension is a confounding factor.This work was supported by grants from the U.S. NIH (R01 HL105297, P01 HL134605, and U01 HL142518)Weiss, D.; Cavinato, C.; Gray, A.; Ramachandra, AB.; Avril, S.; Humphrey, JD.; Latorre, M. (2020). Mechanics-driven mechanobiological mechanisms of arterial tortuosity. Science Advances. 6(49):1-26. https://doi.org/10.1126/sciadv.abd357412664
Observational constraints on the origin of the elements. V. Non-LTE abundance ratios of [Ni/Fe] in Galactic stars and enrichment by sub-Chandrasekhar mass SNe
We constrain the role of different SN Ia channels in the chemical enrichment
of the Galaxy by studying the abundances of nickel in Galactic stars. We
investigate four different SN Ia sub-classes, including the classical
single-degenerate near-Chandrasekhar mass SN Ia, the fainter SN Iax systems
associated with He accretion from the companion, as well as two sub-Ch mass SN
Ia channels. The latter include the double-detonation of a white dwarf
accreting helium-rich matter and violent white dwarf mergers. NLTE models of Fe
and Ni are used in the abundance analysis. In the GCE models, we include new
delay time distributions arising from the different SN Ia channels, as well as
recent yields for core-collapse supernovae and AGB stars. The data-model
comparison is performed using a Markov chain Monte Carlo framework that allows
us to explore the entire parameter space allowed by the diversity of explosion
mechanisms and the Galactic SN Ia rate, taking into account the uncertainties
of the observed data. We show that NLTE effects have a non-negligible impact on
the observed [Ni/Fe] ratios in the Galactic stars. The NLTE corrections to Ni
abundances are not large, but strictly positive, lifting the [Ni/Fe] ratios by
~+0.15 dex at [Fe/H] =-2. We find that that the distributions of [Ni/Fe] in LTE
and in NLTE are very tight, with a scatter of < 0.1 dex at all metallicities,
supporting earlier work. In LTE, most stars have scaled-solar Ni abundances,
[Ni/Fe] = 0, with a slight tendency for sub-solar [Ni/Fe] ratios at lower
[Fe/H]. In NLTE, however, we find a mild anti-correlation between [Ni/Fe] and
metallicity, and a slightly elevated [Ni/Fe] ratios at [Fe/H] < -1.0. The NLTE
data can be explained by the GCE models calculated with a substantial, ~ 75%,
fraction of sub-Ch SN Ia.Comment: accepted for publication in Astronomy & Astrophysics, abridged
version of the abstrac
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