465 research outputs found
Corrigendum: Exploring the Niche Concept in a Simple Metaorganism
[This corrects the article DOI: 10.3389/fmicb.2020.01942.]
Off-stoichiometric softening and polytypic transformations in the plastic deformation of the C14 FeNb Laves phase
Plastic deformation of the brittle C14-FeNb Laves phase occurs mostly by
basal slip due to the complex crystal structure. Here, we compare the barriers
for basal slip for the known mechanisms of direct slip, synchroshear and
undulating slip using density functional theory calculations. According to our
calculated generalized stacking fault (SF) energies, the most favorable
mechanisms are synchroshear and undulating slip. Both mechanisms lead to stable
SF with a formation energy of 50 through the same unstable SF
configuration at the transition. The energy barrier of approximately 3
indicates a low dislocation mobility as expected from the brittle character. We
also determine the influence of vacancies and antisite defects on the formation
energy of stable and unstable SF. Both kinds of point defects tend to lower the
energy barrier on both sides of 2:1 stoichiometry. This explains the
experimentally observed off-stoichiometric softening of C14-FeNb. The small
energy differences between the FeNb Laves phase polytypes raises the
question if there are further deformation mechanisms with low barrier.
Therefore, we additionally consider transformations between C14, C15 and C36
Laves phases as further deformation mechanism. Our calculations for polytypic
transformations by successive synchroshear steps show that the corresponding
energy barriers are in fact very similar to the energy barrier for basal slip
in C14. This suggests that the energy needed to create a stable SF in C14 by
synchroshear is also sufficient to initiate polytypic transformations where
existing SFs in C14 are further transformed to form C15 or C36 Laves phases
OddzOn Products and Derivation of Invention: At Odds with the Purpose of Section 102(f) of the Patent Act of 1952?
Abstract Background Antimicrobial peptides are important components of the host defence with a broad range of functions including direct antimicrobial activity and modulation of inflammation. Lack of cathelin-related antimicrobial peptide (CRAMP) was associated with higher mortality and bacterial burden and impaired neutrophil granulocyte infiltration in a model of pneumococcal meningitis. The present study was designed to characterize the effects of CRAMP deficiency on glial response and phagocytosis after exposure to bacterial stimuli. Methods CRAMP-knock out and wildtype glial cells were exposed to bacterial supernatants from Streptococcus pneumoniae and Neisseria meningitides or the bacterial cell wall components lipopolysaccharide and peptidoglycan. Cell viability, expression of pro- and anti-inflammatory mediators and activation of signal transduction pathways, phagocytosis rate and glial cell phenotype were investigated by means of cell viability assays, immunohistochemistry, real-time RT-PCR and Western blot. Results CRAMP-deficiency was associated with stronger expression of pro-inflammatory and weakened expression of anti-inflammatory cytokines indicating a higher degree of glial cell activation even under resting-state conditions. Furthermore, increased translocation of nuclear factor ‘kappa-light-chain-enhancer’ of activated B-cells was observed and phagocytosis of S. pneumoniae was reduced in CRAMP-deficient microglia indicating impaired antimicrobial activity. Conclusions In conclusion, the present study detected severe alterations of the glial immune response due to lack of CRAMP. The results indicate the importance of CRAMP to maintain and regulate the delicate balance between beneficial and harmful immune response in the brain
Exploring the niche concept in a simple metaorganism
Organisms and their resident microbial communities - the microbiome - form a complex and mostly stable ecosystem. It is known that the composition of the microbiome and bacterial species abundances can have a major impact on host health and Darwinian fitness, but the processes that lead to these microbial patterns have not yet been identified. We here apply the niche concept and trait-based approaches as a first step in understanding the patterns underlying microbial community assembly and structure in the simple metaorganism Hydra. We find that the carrying capacities in single associations do not reflect microbiota densities as part of the community, indicating a discrepancy between the fundamental and realized niche. Whereas in most cases, the realized niche is smaller than the fundamental one, as predicted by theory, the opposite is observed for Hydra’s two main bacterial colonizers. Both, Curvibacter sp. and Duganella sp. benefit from association with the other members of the microbiome and reach higher fractions as compared to when they are the only colonizer. This cannot be linked to any particular trait that is relevant for interacting with the host or by the utilization of specific nutrients but is most likely determined by metabolic interactions between the individual microbiome members
Ab initio study of transition paths between (meta)stable phases of Nb and Ta-substituted Nb
Although Niobium is a well characterized material it still shows some
anomalies that are not yet understood. Therefore we revisit its metastable
phases using density functional theory. First, we systematically compare
energies and ground state volumes of chosen crystal structures and discuss
possible transition paths to the bcc ground state structure and the energy
landscape for tetragonal distortions. Furthermore, we discuss their stability
by means of their phonon spectra and vibronic free energies. Second we analyze
the impact of tantalum impurities on phase stability. Surprisingly we find new
aspects of the energy landscape of the material which have been overlooked so
far: A new local energy minimum on the bcc to omega transition path, a flat
energy landscape with respect to uniaxial strain along [111] and a considerable
stabilization of the sigma phase by Ta substitution
EcoSonic: Auditory Peripheral Monitoring of Fuel Consumption for Fuel-Efficient Driving
Hammerschmidt J, Hermann T. EcoSonic: Auditory Peripheral Monitoring of Fuel Consumption for Fuel-Efficient Driving. Displays. 2017;47(SI):40-50.In this paper, we propose to make use of an auditory fuel efficiency display as means to support car drivers in adopting an energy-efficient driving style. We report on the development of the EcoSonic system as a platform for evaluating such displays and present five design approaches to guide their realization. In a study with 30 participants, we evaluated two prototype auditory displays against the baseline of visual-only eco-driving feedback in a within-subject study. Our selected designs are described in full detail. Key findings include a significantly reduced fuel consumption as well as lower engine speeds compared to the visual display. Furthermore, questionnaire analysis results confirm that the auditory conditions are less obtrusive and also seem to allow a more subconscious processing and comprehension of the provided information. Finally, we have found that the affectiveness of the display design seems to have a positive impact on its perceived helpfulness and the ability to absorb its information subconsciously
- …