31 research outputs found
The mechanisms of humic substances self-assembly with biological molecules: The case study of the prion protein
Humic substances (HS) are the largest constituent of soil organic matter and are considered as a key component of the terrestrial ecosystem. HS may facilitate the transport of organic and inorganic molecules, as well as the sorption interactions with environmentally relevant proteins such as prions. Prions enter the environment through shedding from live hosts, facilitating a sustained incidence of animal prion diseases such as Chronic Wasting Disease and scrapie in cervid and ovine populations, respectively. Changes in prion structure upon environmental exposure may be significant as they can affect prion infectivity and disease pathology. Despite its relevance, the mechanisms of prion interaction with HS are still not completely understood. The goal of this work is to advance a structural-level picture of the encapsulation of recombinant, non-infectious, prion protein (PrP) into different natural HS. We observed that PrP precipitation upon addition of HS is mainly driven by a mechanism of âsalting-outâ whereby PrP molecules are rapidly removed from the solution and aggregate in insoluble adducts with humic molecules. Importantly, this process does not alter the protein folding since insoluble PrP retains its α-helical content when in complex with HS. The observed ability of HS to promote PrP insolubilization without altering its secondary structure may have potential relevance in the context of âprion ecologyâ. These results suggest that soil organic matter interacts with prions possibly without altering the protein structures. This may facilitate prions preservation from biotic and abiotic degradation leading to their accumulation in the environment
Low-mass and sub-stellar eclipsing binaries in stellar clusters
We highlight the importance of eclipsing double-line binaries in our
understanding on star formation and evolution. We review the recent discoveries
of low-mass and sub-stellar eclipsing binaries belonging to star-forming
regions, open clusters, and globular clusters identified by ground-based
surveys and space missions with high-resolution spectroscopic follow-up. These
discoveries provide benchmark systems with known distances, metallicities, and
ages to calibrate masses and radii predicted by state-of-the-art evolutionary
models to a few percent. We report their density and discuss current
limitations on the accuracy of the physical parameters. We discuss future
opportunities and highlight future guidelines to fill gaps in age and
metallicity to improve further our knowledge of low-mass stars and brown
dwarfs.Comment: 30 pages, 5 figures, no table. Review pape
Teaching and supervising tracheal intubation in paediatric patients using videolaryngoscopy
A eficåcia organizacional na percepção do presidente da Federação Portuguesa de Canoagem
Making a Difference in ICT Research: Feminist Theorization of Sociomateriality and the Diffraction Methodology
Part 3: Hybrid Agency and the Performativity of TechnologyInternational audienceOver the last decade, sociomateriality appeared as a theme in IS research that has been interrogated with a variety of theoretical lenses. However, researchers have since raised methodological concerns regarding its application. This paper argues that a research methodology cannot be separated from either the theoretical lens that the research adopts or from its overarching purpose. Considering the broad range of theoretical lenses through which sociomateriality could be examined, this paper focuses on Baradâs theory of agential realism [25]. The paper provides a brief history of agential realism to shed light on the reasons behind IS researchers methodological difficulty and offers a diffraction methodology as a possible methodological guide to IS research adopting this lens. Implication for research is discussed